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NIDDK Investigators
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Kidney Disease Section, Staff Clinician |
B.A., Harvard College, 1975 Research Statement Dr. Kopp is a principal investigator within the Kidney Disease Section of the Metabolic Diseases Branch. Work in his laboratory focuses on the study of focal segmental glomerulosclerosis (FSGS). FSGS occurs in several forms, including idiopathic FSGS, FSGS in association with HIV-1 infection, and FSGS occurring as a consequence of glomerular hyperfiltration due to reduced renal mass. FSGS is characterized by accumulation of glomerular extracellular matrix protein (fibrosis), with progressive loss of kidney function. (1) FSGS Genetic Study: In collaboration with nephrology
investigators around the country and with Dr. Cheryl Winkler,
NCI, NIH, we are collecting DNA samples from patients with
idiopathic and HIV-associated FSGS. We are studying candidate
genes and will initiate a random genome scan based on linkage
disequilibrium. Link
to trial Laboratory projects Publications 1. Dickie P Roberts A Uwiera R Witmer J Sharma K Kopp JB Focal glomerulosclerosis in proviral and c-fms transgenic mice links Vpr expression to HIV-associated nephropathy. Virology (322): 69-81 , 2004. [ Full Text/Abstract] 2. Yo Y Braun MC Barisoni L Mobaraki H Lu H Shrivastav S Owens J Kopp JB Anti-mouse mesangial cell serum induces acute glomerulonephropathy in mice. Nephron Exp Nephrol (93): e92-106 , 2003. [ Full Text/Abstract] 3. Kim JM Wu H Green G Winkler CA Kopp JB Miner JH Unanue ER Shaw AS CD2-associated protein haploinsufficiency is linked to glomerular disease susceptibility. Science (300): 1298-300 , 2003. [ Full Text/Abstract] 4. Shigehara T Zaragoza C Kitiyakara C Takahashi H Lu H Moeller M Holzman LB Kopp JB Inducible podocyte-specific gene expression in transgenic mice. J Am Soc Nephrol (14): 1998-2003 , 2003. [ Full Text/Abstract]
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Allan D. Kirk, M.D., Ph.D., F.A.C.S. Transplantation
Branch , Chief |
Biographical Sketch Multi-organ Transplant Fellowship,University of Wisconsin
1995-1997 Research Statement When patients undergo an organ transplant procedure, they are required to take immunosuppressive medications for life to prevent immune rejection of the transplanted organ. These drugs do not only alter the immune response against the transplanted organ, they also impair the response to infections and some types of cancers. Immunosuppressive drugs thus cause significant cost in terms of infectious, malignant and physiological side effects. In essence, transplant patients trade a disease for a condition. Conventional wisdom has held that since the immune system causes rejection, it must be suppressed to prevent graft loss. My lab, and those of others, is showing otherwise. The immune system is not an offensive system that acts without control. Rather, it is an elegant defensive network that is tightly regulated to provide protective immunity through carefully controlled responses to specific threats like infections. As such, it must turn responses off as well as turn them on. Indeed, the immune system is as capable of preventing rejection as it is of causing it. My research has been directed toward understanding the way the immune system regulates itself and using these methods to achieve transplant tolerance – a state in which the immune response favors acceptance of an organ rather than rejection. My primary goals lie in the transition of promising therapies from the laboratory into proof of concept clinical trials. My group thus uses animal models of transplantation to develop therapies for initial clinical use. Therapies that show promise are investigated in humans at the Clinical Center under approved kidney transplant protocols. My lab is currently investigating several methods for tolerance induction. One critical regulatory pathway involved in T cell immunity involves the costimulation receptor-ligand pair CD40: CD154. We have been successful in targeting CD154 with monoclonal antibodies to prevent allograft rejection in non-human primates without chronic immunosuppression. We are now evaluating multiple sources of anti-CD154 pre-clinically and evaluating other agents that behave synergistically to transition this approach into the clinic. Of particular interest is the expression of CD154 on activated platelets and the implications this has for immune activation caused by surgical trauma. We are particularly focused on platelet-monocyte interactions with the hypothesis that trauma induced platelet activation contributes to initial antigen presenting cell activation and maturation. Other costimulatory molecules being investigated include the B7 molecules CD80 and CD86. We have initiated three clinical trials based on the concept that transient depletion of immune cells prevents immune activation that is induced by the trauma of surgery, and pushes the immune response towards tolerance rather than rejection. Using the monoclonal antibody alemtuzumab (Campath-1H), or alternatively the polyclonal antibody preparation Thymoglobulin to achieve transient T cell depletion prior to allograft reperfusion, we have been able to substantially reduce the need for postoperative immunosuppression in humans and avoid the chronic use of steroids. This is presumably due to the avoidance of antigen presentation to T cells at the peak of immune activation (the surgical procedure itself). We are now modeling several variations of this approach in non-human primates to understand how a reconstituting immune system engages a transplanted organ. Again, monocyte activation plays a key role in this response and we are evaluating human allograft derived monocyte populations to gain clues into their regulation at the time of a traumatic insult. CD40 ligation clearly plays a role in this approach as well, though responses to reperfusion associated cytokines and responses to graft derived cellular debris or apoptosis appear to be important immune modulates that are receiving critical attention. Finally, our group is developing many new methods for evaluating transplant recipients to determine more precisely how much immunosuppression they need. Using the molecular technique polymerase chain reaction (PCR) we are studying the genes that are associated with organ rejection and acceptance. It is hoped that with new immune therapies, and more precise ways of following patients’ needs, we can “tailor-make” immune therapies to give patients only the medication they need to maintain good health. Publications 1. Kirk AD Crossing the bridge: large animal models in translational transplantation research. Immunol Rev (196): 176-96 , 2003. [ Full Text/Abstract] 2. Hoffmann SC Pearl JP Blair PJ Kirk AD Immune profiling: molecular monitoring in renal transplantation. Front Biosci (8): e444-62 , 2003. [ Full Text/Abstract] 3. Kirk AD Less is more: maintenance minimization as a step toward tolerance. Am J Transplant (3): 643-5 , 2003. [ Full Text/Abstract] 4. Gorbach A Simonton D Hale DA Swanson SJ Kirk AD Objective, real-time, intraoperative assessment of renal perfusion using infrared imaging. Am J Transplant (3): 988-93 , 2003. [ Full Text/Abstract]
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Gastrointestinal Cell Biology Section, Chief |
B.S., Washington State University, 1964 Research Statement The section on Gastrointestinal Cell Biology is involved in research involving the cellular basis of action of gastrointestinal hormones (primarily bombesin related peptides-gastrin-releasing peptide, neuromedin B, CCK related peptides and VIP-secretin related peptides) as well as clinical and laboratory studies on human gastric acid hypersecretory states such as Zollinger-Ellison syndrome. The studies on GI hormones involve intracellular signaling cascades especially tyrosine phosphorylation (primarily CCK, Bombesin), molecular pharmacology of their receptors (especially Bombesin related peptides), and structure function studies of various receptor ligands to develop selective agonists and antagonists. In addition laboratory studies characterizing the bombesin related receptor, BRS-3 as well as developing ligands to deliver receptor specific chemotherapy to tumors ectopically expressing these receptors is being studied. Studies of patients with Zollinger-Ellison syndrome involve clinical studies of the diagnosis, localization, and treament of the gastrinoma as well as Multiple endocrine Neoplasia thype 1 which occurs in a propostion of the patients. Laboratory studies involve the characterization of the molecular pathogenesis of gastrinomas and identification of useful prognostic factors. Publications 1. Moody TW Mantey SA Pradhan TK Schumann M Nakagawa T Martinez A Fuselier J Coy DH Jensen RT Development of high affinity camptothecin-bombesin conjugates that have targeted cytotoxicity for bombesin receptor-containing tumor cells. J Biol Chem (279): 23580-9 , 2004. [ Full Text/Abstract] 2. Norton JA Alexander HR Fraker DL Venzon DJ Gibril F Jensen RT Does the use of routine duodenotomy (DUODX) affect rate of cure, development of liver metastases, or survival in patients with Zollinger-Ellison syndrome? Ann Surg (239): 617-25; discussion 626 , 2004. [ Full Text/Abstract] 3. Gibril F Schumann M Pace A Jensen RT Multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome: a prospective study of 107 cases and comparison with 1009 cases from the literature. Medicine ( Baltimore) (83): 43-83 , 2004. [ Full Text/Abstract] 4. Chen YJ Vortmeyer A Zhuang Z Gibril F Jensen RT X-chromosome loss of heterozygosity frequently occurs in gastrinomas and is correlated with aggressive tumor growth. Cancer (100): 1379-87 , 2004. [ Full Text/Abstract]
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Molecular Recognition Section, Chief |
B.A., Reed College, 1976
Research Statement Dr. Jacobson is a medicinal chemist with interests in the structure and pharmacology of receptors and in developing drugs that act as agonists or antagonists of G protein-coupled receptors (GPCRs). The current focus is on receptors for purines, encompassing both adenosine receptors and P2 receptors, which are activated by ATP and UTP. Dr. Jacobson has taken an interdisciplinary approach to studying the chemical and biological aspects of these receptors. He has developed a "functionalized congener approach" to drug design. Novel ligands (small molecules) for these receptors are developed using classical synthetic approaches and also by semi-rational methods based on molecular modeling and template design. Receptors are computer-modeled by homology to rhodopsin, and the models for ligand recognition are tested and refined using site-directed mutagenesis of the receptor proteins. Recently, the involvement of extracellular loops of GPCRs have been implicated in the receptor binding of small molecules, as demonstrated through the mutagenesis and modeling of P2Y1 receptors. Substances developed as potent and selective agents acting through adenosine and P2 receptors have proven useful as pharmacological probes and have potential for treating diseases of the central nervous system, immune system, and cardiovascular system. Recent accomplishments include the design and synthesis of the first A3 adenosine receptor agonists and antagonists, using a combination of library screening and optimization of known adenosine receptor ligands. These substances have been shown to be effective in models of treatment of glaucoma, cancer, stroke, and cardiac ischemia. A selective A3 adenosine receptor agonists is currently in clinical trials for colon carcinoma. We have synthesized the first P2Y1 receptor-selective antagonists, through functionalization of adenine nucleotides. The antagonists were optimized with the aid of receptor homology modeling. These substances have been shown to be effective in models of antithrombotic treatment, due to blockade of the proaggregatory effects of ADP. The pharmacological probes designed in our section have been used to demonstrate the connection between purine receptors and apoptosis (programmed cell death). A3 adenosine receptor agonists at low concentrations and P2Y6 receptor agonists have antiapoptotic effects. Another potential means of using the protective effects of AR activation was achieved through receptor engineering. Constitutively active mutant A3 adenosine receptors, in principle, could be delivered by tissue-targeted vectors for gene therapy. In addition, we have introduced the approach of “neoceptors”, also intended for eventual use in gene therapy, in which the putative agonist binding site is redesigned to accept only agonist molecules altered in a complementary fashion. Insight into the recognition of agonist by the receptors may be gained using site-directed mutagenesis and molecular modeling. We are exploring this approach conceptually with tailor-made agonist ligands (“neoligands” that are selective for the neoceptor and not the native receptor) in combination with receptor mutagenesis. The neoceptor concept has so far been applied to A2A and A3 adenosine receptors. Publications 1. Kim HS Ohno M Xu B Kim HO Choi Y Ji XD Maddileti S Marquez VE Harden TK Jacobson KA 2-Substitution of adenine nucleotide analogues containing a bicyclo[3.1.0]hexane ring system locked in a northern conformation: enhanced potency as P2Y1 receptor antagonists. J Med Chem (46): 4974-87 , 2003. [ Full Text/Abstract] 2. Gao ZG Chen A Barak D Kim SK Muller CE Jacobson KA Identification by site-directed mutagenesis of residues involved in ligand recognition and activation of the human A3 adenosine receptor. J Biol Chem (277): 19056-63 , 2002. [ Full Text/Abstract] 3. Jacobson KA Jarvis MF Williams M Purine and pyrimidine (P2) receptors as drug targets. J Med Chem (45): 4057-93 , 2002. [ Full Text/Abstract] 4. Gao ZG Kim SK Biadatti T Chen W Lee K Barak D Kim SG Johnson CR Jacobson KA Structural determinants of A(3) adenosine receptor activation: nucleoside ligands at the agonist/antagonist boundary. J Med Chem (45): 4471-84 , 2002. [ Full Text/Abstract] |
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Biology of the Mammary Gland Section, Chief
Research Statement Identify and explore genetic switches and biochemical pathways that control organogenesis, with an emphasis on the mammary gland. Investigate pathways that control oncogenic transformation in the mammary gland and prostate. We have identified genes, which are critical for normal mammary development, and their role is being studied through their deletion from the mouse genome by homologous recombination and their deregulated expression in mammary tissue of transgenic mice. We have established that the prolactin - Jak2/Stat5 pathway is critical for the specification, proliferation and differentiation of mammary epithelium. Current projects include the analysis of the prolactin/Jak2/Stat5 and b-catenin signaling pathway in cell specification and cell fate determination, the roles of inhibinbB and C/EBPb in mammary development and function, and the role of Bcl-2 family members on mammary gland remodeling during involution. Experimental emphasis is on the establishment of genetic systems that permit the cell-specific and temporal inactivation and reactivation of genes in the mouse. In addition, LGP has established public resource for the field of mammary gland biology, the 'Biology of the Mammary Gland' web site, and the NIH Histobank, a repository for high-resolution images from mouse models and human disease. Publications 1. Miyoshi K Shillingford JM Le Provost F Gounari F Bronson R von Boehmer H Taketo MM Cardiff RD Hennighausen L Khazaie K Activation of beta -catenin signaling in differentiated mammary secretory cells induces transdifferentiation into epidermis and squamous metaplasias. Proc Natl Acad Sci U S A (99): 219-24 , 2002. [ Full Text/Abstract] 2. Shillingford JM Miyoshi K Robinson GW Grimm SL Rosen JM Neubauer H Pfeffer K Hennighausen L Jak2 is an essential tyrosine kinase involved in pregnancy-mediated development of mammary secretory epithelium. Mol Endocrinol (16): 563-70 , 2002. [ Full Text/Abstract] 3. Miyoshi K Shillingford JM Smith GH Grimm SL Wagner KU Oka T Rosen JM Robinson GW Hennighausen L Signal transducer and activator of transcription (Stat) 5 controls the proliferation and differentiation of mammary alveolar epithelium. J Cell Biol (155): 531-42 , 2001. [ Full Text/Abstract] 4. Hennighausen L Robinson GW Signaling pathways in mammary gland development. Dev Cell (1): 467-75 , 2001. [ Full Text/Abstract] |
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Laboratory
of Cell Biochemistry and Biology , Chief |
B.S., University of Tulsa, 1976 Research Statement
Publications 1. Vocadlo DJ, Hang HC, Kim EJ, Hanover JA, Bertozzi CR. A chemical approach for identifying O-GlcNAc-modified proteins in cells. Proc Natl Acad Sci U S A (100): 9116-21, 2003. 2. Love DC, Kochan J, Cathey RL, Shin SH, Hanover JA Mitochondrial and nucleocytoplasmic targeting of O-linked GlcNAc transferase. J Cell Sci(116): 647-54, 2003. 3. McClain, DA, Lubas, WA, Cooksey, RC, Hazel, M, Parker, GJ, Love DC, Hanover, JA Altered glycan-dependent signaling induces insulin resistance and hyperleptinemia. Proc Natl Acad Sci U S A(99): 10695-9, 2002. 4. Hanover, JA Glycan-Dependent Signaling: O-linked N-acetylglucosamine FASEB J(15): 1865-1876, 2001. |
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Transplantation
Branch , Investigator |
Biographical Sketch Education
Research Statement While the results of organ transplantation have improved considerably over the past decade, these results are predicated upon the need to take potent immunosuppressive drugs for as long as the transplanted organ continues to function. Unfortunately, while these drugs can hold the immune system at bay to a certain extent, they are associated with adverse effects that can reduce the function of the transplanted organ and even shorten the life of the patient. As a consequence, we are attempting to develop methods of reducing and eventually eliminating the requirement for long-term immunosuppression. To accomplish this, the transplant recipient’s immune system must be manipulated in such a way that it does not mount an attack against the transplanted organ. When this state is achieved it is termed tolerance. The current focus of research conducted in this laboratory is the refinement and clinical adaptation of a donor bone marrow based tolerance induction protocol. Through decades of experimental work in animals and humans conducted by investigators at a variety of research institutions, we know that if donor bone marrow can be made to, at least transiently coexist within the recipient’s bone marrow, the recipient will not reject an organ transplant obtained from the same donor. The difficulty in this approach lies in attaining a state of stable co-existence (called mixed chimerism). To date, the methods that have had to be employed to achieve mixed chimerism in animal studies have either been considered too radical (i.e. radiation or strong chemotherapy) to justify application in humans or required drugs/agents not available for use in humans. We have developed a method of achieving mixed chimerism in mice using a relatively non-toxic conditioning regimen using a combination of anti-lymphocyte antibodies, sirolimus, low dose busulfan and donor bone marrow. A major focus of our laboratory effort is the further refinement and successful adaptation of this approach to higher animal models and eventually, humans. Work conducted in nonhuman primates has indicated several potential areas where the regimen may require modification in order to maximize safety and efficacy in humans. Moreover, we have initiated a clinical study that seeks to determine whether the administration of donor bone marrow to patients treated with anti-lymphocyte antibodies and sirolimus will eventually permit immunosuppression to be withdrawn. We consider this a first step in the development of a safe and reliable method for inducing tolerance though the administration of donor bone marrow and fully expect to modify the conditioning regimen as the accumulated experience with it warrants. Publications 1. Akpinar E, Craighead N, Smoot D, Hale DA. Potent skin allograft survival prolongation using a committed progenitor fraction of bone marrow in mice. Transplantation, 2004. 2. Hale DA Gottschalk R Umemura A Maki T Monaco AP Immunologic mechanisms in tolerance produced in mice with nonradiation-based lymphoablation and donor-specific bone marrow. Transplantation (74): 477-84 , 2002. [ Full Text/Abstract] 3. Swanson SJ Hale DA Mannon RB Kleiner DE Cendales LC Chamberlain CE Polly SM Harlan DM Kirk AD Kidney transplantation with rabbit antithymocyte globulin induction and sirolimus monotherapy. Lancet (360): 1662-4 , 2002. [ Full Text/Abstract] 4. Hale DA Gottschalk R Umemura A Maki T Monaco AP Establishment of stable multilineage hematopoietic chimerism and donor-specific tolerance without irradiation. Transplantation (69): 1242-51 , 2000. [ Full Text/Abstract] |
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Division
of Intramural Research, Director |
B.S., City College of the City University of New York, 1967
Research Statement 1) Conducts research aimed at characterizing the progenitors of the cells of the endocrine pancreas (islets of Langerhans) including insulin-producing beta cells, glucagon-producing alpha cells, somatostatin-producing delta cells and pancreatic polypeptide-producing cells. 2) Investigates the extracellular regulatory factors and the signal transduction mechanisms that mediate insulin secretion from the islets of Langerhans. 3) Studies the structure-function relationships of G protein-coupled receptors; in particular, receptors for thyrotropin-releasing hormone and glucagon-like peptide 1 Publications 1. Couty JP Gershengorn MC Insights into the viral G protein-coupled receptor encoded by human herpesvirus type 8 (HHV-8). Biol Cell (96): 349-54 , 2004. [ Full Text/Abstract] 2. Hardikar AA Marcus-Samuels B Geras-Raaka E Raaka BM Gershengorn MC Human pancreatic precursor cells secrete FGF2 to stimulate clustering into hormone-expressing islet-like cell aggregates. Proc Natl Acad Sci U S A (100): 7117-22 , 2003. [ Full Text/Abstract] 3. Jain R Singh J Perlman JH Gershengorn MC Synthesis and biology of new thyrotropin-releasing hormone (TRH) analogues. Bioorg Med Chem (10): 189-94 , 2002. [ Full Text/Abstract]
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Genetics
of Development and Disease Branch , Senior Investigator |
B.S., Nanchong Normal University, China, 1981
Research Statement The primary interest of my group is mammalian development
and tumorigenesis using animal model systems. We have the following
three projects. Functions of Smad genes Functions of Brca1 gene Publications 1. Tang Y Katuri V Dillner A Mishra B Deng CX Mishra L Disruption of transforming growth factor-beta signaling in ELF beta-spectrin-deficient mice. Science (299): 574-7 , 2003. [ Full Text/Abstract] 2. Bachelier R Xu X Wang X Li W Naramura M Gu H Deng CX Normal lymphocyte development and thymic lymphoma formation in Brca1 exon-11-deficient mice. Oncogene (22): 528-37 , 2003. [ Full Text/Abstract] 3. Cao L Li W Kim S Brodie SG Deng CX Senescence, aging, and malignant transformation mediated by p53 in mice lacking the Brca1 full-length isoform. Genes Dev (17): 201-13 , 2003. [ Full Text/Abstract] 4. Li W Qiao W Chen L Xu X Yang X Li D Li C Brodie SG Meguid MM Hennighausen L Deng CX Squamous cell carcinoma and mammary abscess formation through squamous metaplasia in Smad4/Dpc4 conditional knockout mice. Development (130): 6143-53 , 2003. [ Full Text/Abstract]
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Laboratory
of Cellular and Developmental Biology , Chief |
B.A., Columbia College, Columbia University, 1969
Research Statement We study the developmental biology of the mammalian ovary using mouse as an experimental system. In particular, we investigate molecular mechanisms used by oocyte-specific, maternal factors to promote folliculogenesis, ensure fertilization and activate the embryonic genome. At birth the ovary contains its full complement of germ cells, each surrounded by a single layer of granulosa cells which together form the primordial follicles. We have identified a novel, oocyte-specific, basic helix-loop-helix transcription factor, FIGa (Factor In the Germline, alpha). The single-copy Figa gene has been disrupted in embryonic stem cells and these cells have been used to establish mouse lines. Female mice lacking FIGa are sterile because of germ cell depletion secondary to an inability to form primordial follicles perinatally. Identification of downstream targets of FIGa should provide additional insights into the molecular basis of follicle formation. After the onset of folliculogenesis, FIGa also modulates the oocyte-specific expression of the single-copy genes that encode ZP1, ZP2 and ZP3. Normally, the three zona glycoproteins are secreted during folliculogenesis to form the zona pellucida, an extracellular matrix that mediates order-specific sperm binding to the egg. Using transgenesis, we have determined that mouse ZP1 is not required for formation of the zona pellucida, taxon-specific sperm binding or fertility. In contrast, ZP2 and ZP3 are required for matrix formation without which mice are infertile. Although the replacement of mouse ZP2 and/or ZP3 with human homologues restores the zona pellucida matrix, it does not affect the taxon-specificity of sperm binding (i.e., mouse, but not human, sperm bind and fertilize eggs enclosed in ´humanized´ zonae pellucidae). The post-fertilization persistence of sperm binding and the presence of intact human ZP2 supports a model in which the pre-fertilization zona pellucida has a supramolecular structure that is permissive for sperm binding. The normal post-fertilization cleavage of ZP2 modifies the three-dimensional structure making it non-permissive for sperm binding without obligatory loss of constitutive zona components. Molecular biology and transgenesis is being used to validate this model and determine the molecular basis of sperm-egg recognition. In collaboration with others, we have also identified an oocyte-specific cytoplasmic protein, MATER (Maternal Antigen That Embryos Require), and have shown that it is required for progression of the embryo beyond the early cleavage stage. Efforts are underway to define the molecular basis of this maternal effect phenotype. Publications 1. Dean J Reassessing the molecular biology of sperm-egg recognition with mouse genetics. Bioessays (26): 29-38 , 2004. [ Full Text/Abstract] 2. Rankin TL Coleman JS Epifano O Hoodbhoy T Turner SG Castle PE Lee E Gore-Langton R Dean J Fertility and taxon-specific sperm binding persist after replacement of mouse sperm receptors with human homologs. Dev Cell (5): 33-43 , 2003. [ Full Text/Abstract] 3. Zhao M Gold L Dorward H Liang LF Hoodbhoy T Boja E Fales HM Dean J Mutation of a conserved hydrophobic patch prevents incorporation of ZP3 into the zona pellucida surrounding mouse eggs. Mol Cell Biol (23): 8982-91 , 2003. [ Full Text/Abstract] 4. Boja ES Hoodbhoy T Fales HM Dean J Structural characterization of native mouse zona pellucida proteins using mass spectrometry. J Biol Chem (278): 34189-202 , 2003. [ Full Text/Abstract]
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Laboratory
of Cellular and Developmental Biology , Senior Investigator |
B.A., Bucknell University,, 1966
Research Statement The laboratory studies how enhancers activate transcription during development and differentiation, with particular interest in the role played by chromatin structure in this process. The model system employed is the family of human globin genes that are expressed in a tissue specific and developmentally regulated fashion under the influence of the beta-globin locus control region enhancer (LCR). Studies are being carried out to map the precise changes in nucleosome organization that accompany gene activation, and to understand the role of transcription factors, and transcription and replication per se. Other studies using mutagenesis, and in vitro and in vivo ligation approaches, are addressing the extent to which the interaction of a promoter and an enhancer involves close contact. Another area of interest is in establishing which transcription factors and mediators are actually bound in vivo to a transcribing gene promoter or enhancer by using cross linking and immunoprecipitation. The goal of these studies is to understand the complex interplay between nuclear genes and their modulators. Understanding the role of chromatin structure in gene regulation is important to gene therapy efforts. Publications 1. Kim A Dean A A human globin enhancer causes both discrete and widespread alterations in chromatin structure. Mol Cell Biol (23): 8099-109 , 2003. [ Full Text/Abstract] 2. Gui CY Dean A A major role for the TATA box in recruitment of chromatin modifying complexes to a globin gene promoter. Proc Natl Acad Sci U S A (100): 7009-14 , 2003. [ Full Text/Abstract] 3. Jackson DA McDowell JC Dean A Beta-globin locus control region HS2 and HS3 interact structurally and functionally. Nucleic Acids Res (31): 1180-90 , 2003. [ Full Text/Abstract] 4. Gui CY Dean A Acetylation of a specific promoter nucleosome accompanies activation of the epsilon-globin gene by beta-globin locus control region HS2. Mol Cell Biol (21): 1155-63 , 2001. [ Full Text/Abstract] ]
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Pharmacology Section, Senior Investigator |
B.A., Talladega College, 1964
Research Statement Our research focuses on the understanding of the mechanisms of bacterial pathogenesis and antibiotic resistance of gram-negative bacteria, specifically as they relate to ulcer disease and other bacterial infections. We perform basic research on enzymes responsible for lipopolysaccharide (LPS) synthesis in gram-negative bacteria, utilizing techniques in bacterial genetics, molecular biology, protein chemistry, enzymology, and x-ray crystallography. The goal is to characterize enzymic processes that have therapeutic implications for human disease. Our current research initiatives emphasize the understanding of the structure and function of LPS biosynthetic enzymes, the role of LPS in the pathology of E. coli and Helicobacter pylori and the evaluation of specific enzymes in the LPS biosynthesis pathway as potential novel antibiotic targets. L-Glycero-D-mannoheptose (heptose) is a 7-carbon sugar present in the lipopolysaccharide of a wide variety of gram-negative bacteria. Heptose provides a link between lipid A-KDO, the outer core and the O-antigen regions of LPS. ADP-L-glycero-D- mannoheptose 6-epimerase (epimerase) is required for the synthesis of the heptose precursor, ADP-L-glycero-D-mannoheptose. Gram-negative bacteria without epimerase activity have the following characteristics: severely truncated LPS, increased sensitivity to gastric bile and serum killing, hypersensitivity to a number of hydrophobic agents including antibiotics, decreased pathogenicity. The essential role of the epimerase in the synthesis of LPS and the ability of gram-negative bacteria to thrive in human hosts makes it an attractive target for antimicrobial agents. To fully realize the potential of the epimerase as a novel target for therapeutic attack requires detailed knowledge of the structure and catalytic mechanism of this enzyme. Therefore, we have undertaken X-ray crystallographic studies to determine the three-dimension structure and catalytic mechanism of the E. coli K-12 epimerase. Helicobacter pylori plays a major role in gastritis, peptic ulcer disease and gastric carcinoma. Although several pathogenic determinants have been proposed, the mechanism of pathogenesis is not yet known. Studies are ongoing to identify and characterize novel targets for the development of antibiotics and protective vaccines directed against Helicobacter pylori. The Helicobacter pylori studies are collaborative efforts between my research group and the Diagnon Corporation. Publications 1. Nyan DC Welch AR Dubois A Coleman WG Jr Development of a Nonivasive Method for Detecting and Monitoring the Time Course of Helicobacter pylori Infection Infect. Immun.(72), 2004. [In Press] 2. Read JA Ahmed RA Morrison JP Coleman WG Jr Tanner ME The Mechanism of the Reaction Catalyzed by ADP-beta-l-glycero-d-manno-heptose 6-Epimerase. J Am Chem Soc (126): 8878-8879 , 2004. [ Full Text/Abstract] 3. Ni Y McPhie P Deacon A Ealick S Coleman WG Jr Evidence that NADP+ is the physiological cofactor of ADP-L-glycero-D-mannoheptose 6-epimerase. J Biol Chem (276): 27329-34 , 2001. [ Full Text/Abstract] 4. Deacon AM Ni YS Coleman WG Jr Ealick SE The crystal structure of ADP-L-glycero-D-mannoheptose 6-epimerase: catalysis with a twist. Structure Fold Des (8): 453-62 , 2000.]
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Experimental Diabetes, Metabolism, and Nutrition Section,
Investigator |
B.S., Bowdoin College,, 1963
Research Statement Insulin stimulates glucose transport in its target tissues through the translocation of intracellular glucose transporters, primarily GLUT4, to the plasma membrane. This process is further modulated by the counterregulatory hormones (eg. isoproterenol and adenosine) and other agents which activate the heterotrimeric G-proteins Gs and Gi. Insulin appears to stimulate GLUT4 translocation primarily through an increase in exocytosis. The counterregulatory hormones appear to modulate the fusion of GLUT4-containing vesicles docked to the plasma membrane. Studies are in progress using photoaffinity labeling, subcellular fractionation and immunoblotting, transient transfection, and confocal microscopy to study the regulation of glucose transporter subcellular trafficking by insulin and the counterregulatroy hormones, in isolated rat adipose cells and skeletal muscle. The mechanisms of insulin resistant glucose transport in diabetes mellitus and obesity are also under investigation. Back to TopBack to Top Publications 1. Dawson K Aviles-Hernandez A Cushman SW Malide D Insulin-regulated trafficking of dual-labeled glucose transporter 4 in primary rat adipose cells. Biochem Biophys Res Commun (287): 445-54 , 2001. [ Full Text/Abstract] 2. Malide D Yewdell JW Bennink JR Cushman SW The export of major histocompatibility complex class i molecules from the endoplasmic reticulum of rat brown adipose cells is acutely stimulated by insulin. Mol Biol Cell (12): 101-14 , 2001. [ Full Text/Abstract] 3. Lampson MA Racz A Cushman SW McGraw TE Demonstration of insulin-responsive trafficking of GLUT4 and vpTR in fibroblasts. J Cell Sci 113 ( Pt 22): 4065-76 , 2000. [ Full Text/Abstract] 4. Malide D Ramm G Cushman SW Slot JW Immunoelectron microscopic evidence that GLUT4 translocation explains the stimulation of glucose transport in isolated rat white adipose cells. J Cell Sci (113 Pt 23): 4203-10 , 2000. [ Full Text/Abstract]
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| Rafael Daniel Camerini-Otero, M.D., Ph.D.
Genetics
and Biochemistry Branch , Chief |
B.S., Massachusetts Institute of Technology, 1966 Research Statement My laboratory is interested in the biochemistry and molecular biology of homologous recombination in prokaryotes and eukaryotes. The focus had been on the first homology-dependent step in homologous recombination, the homologous pairing of DNAs. We have been studying the underlying biochemical mechanism for its own sake, to understand the biology of genetic recombination and to devise new strategies to manipulate complex genomes in vitro and, in the future, in vivo.- Specific projects include biophysical and structural studies of some of the proteins, protein domains and DNA-protein complexes involved, new methods for gene mapping and cloning (e.g., RARE and sequence-specific ligation of DNA) and gene targeting in mammalian cells, gene rearrangements in eukaryotes, novel approaches to gene therapy (including the use of small molecules that promote gene targeting, such as miniRecAs)and, most recently, mouse meiosis and evolutionary genomics. Publications 1. Khil PP Smirnova NA Romanienko PJ Camerini-Otero RD The mouse X chromosome is enriched for sex-biased genes not subject to selection by meiotic sex chromosome inactivation. Nat Genet (36): 642-6 , 2004. [ Full Text/Abstract] 2. Voloshin ON Vanevski F Khil PP Camerini-Otero RD Characterization of the DNA damage-inducible helicase DinG from Escherichia coli. J Biol Chem (278): 28284-93 , 2003. [ Full Text/Abstract] 3. Petukhova GV Romanienko PJ Camerini-Otero RD The Hop2 protein has a direct role in promoting interhomolog interactions during mouse meiosis. Dev Cell (5): 927-36 , 2003. [ Full Text/Abstract] 4. Khil PP Camerini-Otero RD Over 1000 genes are involved in the DNA damage response of Escherichia coli. Mol Microbiol (44): 89-105 , 2002. [ Full Text/Abstract]
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Genetics
of Development and Disease Branch , Investigator |
B.S., SUNY at Buffalo, 1989 Research Statement The primary interest of this laboratory is to understand how perturbations during normal development process can lead to cancer. In particular, Wilms' tumor, a childhood kidney cancer, serves as a paradigm for studying development and cancer in our laboratory. The Wilms' tumor suppressor gene, WT1, is mutated in 10-15% of Wilms' tumor and it encodes a transcription factor with four C2H2 zinc fingers as its DNA binding domain. In addition to Wilms' tumor, mutations inWT1 are found in other human diseases such as WAGR, Danys-Drash and Frasier syndromes, all of which display developmental defects in both kidneys and gonads. WAGR and Danys-Drash patients also suffer from an increased risk of Wilms' tumor. WT1 is proposed to regulate the transcription of genes that are critical for the initiation and differentiation of kidneys, gonads, spleen, and the adrenal gland since wt1-null mouse embryos lack all of these organs. Our laboratory is focused on the identification of WT1 target genes that initiate and coordinate organogenesis of the affected tissues, as well as identifying WT1-containing complexes. We are using microarray and chromatin-IP techniques to identify and verify potential WT1-target genes. Identification of the target genes and defining their role during development will provide further insights to the development of Wilms' tumor and organogenesis in general. Ewing's sarcoma and related small round cell tumors have distinct characteristics, which involve translocation (fusion of two different chromosomes) of the Ewing's sarcoma gene (EWS) to various transcription factor-encoding genes. The prototype is the EWS/Fli-I translocation found in about 80% of Ewing's sarcoma. Desmoplastic small round cell tumor (DSRCT) is another example of such translocation found in the tumor cells where it fuses EWS gene to the WT1 gene. Currently, there is no effective treatment for DSRCT and the pathways that are responsible for generating the tumor are largely undefined. To identify the mechanisms of tumorigenesis in DSRCT, we are attempting to generate a mouse model of DSRCT by expressing the EWS/WT1 translocated gene product in mouse embryonic stem cells. The mouse model, if successful, will then be used to dissect molecular pathways that are responsible for the formation of DSRCT, which can lead to the development of new therapeutics against DSRCT-specific molecular targets. Publications 1. Srichai MB Konieczkowski M Padiyar A Konieczkowski DJ Mukherjee A Hayden PS Kamat S El-Meanawy MA Khan S Mundel P Lee SB Bruggeman LA Schelling JR Sedor JR A WT1 co-regulator controls podocyte phenotype by shuttling between adhesion structures and nucleus. J Biol Chem (279): 14398-408 , 2004. [ Full Text/Abstract] 2. Palmer RE Lee SB Wong JC Reynolds PA Zhang H Truong V Oliner JD Gerald WL Haber DA Induction of BAIAP3 by the EWS-WT1 chimeric fusion implicates regulated exocytosis in tumorigenesis. Cancer Cell (2): 497-505 , 2002. [ Full Text/Abstract] 3. Wong JC Lee SB Bell MD Reynolds PA Fiore E Stamenkovic I Truong V Oliner JD Gerald WL Haber DA Induction of the interleukin-2/15 receptor beta-chain by the EWS-WT1 translocation product. Oncogene (21): 2009-19 , 2002. [ Full Text/Abstract] 4. Wang W Lee SB Palmer R Ellisen LW Haber DA A functional interaction with CBP contributes to transcriptional activation by the Wilms tumor suppressor WT1. J Biol Chem (276): 16810-6 , 2001. [ Full Text/Abstract] |
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Diabetes
Branch , Chief |
M.D., Cape Town, South Africa, 1967 Research Statement The Section on Molecular and Cellular Physiology, Clinical Endocrinology Branch is involved in researching the role of the Insulin-like Growth Factors (IGFs) in normal physiology and disease states including diabetes and cancer.These studies include IGF-I receptor signaling, regulation of the IGF-I receptor gene expression and tissue-specific, conditional knockouts of the genes for IGF-I and the IGF-I receptor. In addition, the laboratory studies the role of the newly characterized sulfonylurea receptor in pancreatric and extra-pancreatic tissues and the regulation of this receptor. Publications 1. Yakar S Liu JL Stannard B Butler A Accili D Sauer B LeRoith D Normal growth and development in the absence of hepatic insulin-like growth factor I. Proc Natl Acad Sci U S A (96): 7324-9 , 1999. [ Full Text/Abstract] 2. Derek LeRoith Insulin-like growth factors. New England J. Medicine (336): 633-640, 1997. 3. Werner H Karnieli E Rauscher FJ LeRoith D Wild-type and mutant p53 differentially regulate transcription of the insulin-like growth factor I receptor gene. Proc Natl Acad Sci U S A (93): 8318-23 , 1996. [ Full Text/Abstract] 4. LeRoith D Werner H Beitner-Johnson D Roberts CT Jr Molecular and cellular aspects of the insulin-like growth factor I receptor. Endocr Rev (16): 143-63 , 1995. [ Full Text/Abstract]
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Molecular and Clinical Nutrition Section, Chief |
B.A., Brandeis University, 1973 Research Statement Recommended dietary allowances (RDAs) for vitamin C (ascorbate) have been based on preventing the deficiency disease scurvy. We proposed that new RDAs for vitamin C and other vitamins could be determined using in situ kinetics, a concept developed by this laboratory. In situ kinetics has biochemical and clinical goals. The biochemical goals are to determine vitamin C molecular functions in relation to vitamin concentrations. For these studies vitamin C is investigated in human tissues such as fibroblasts and neutrophils. To determine how intracellular concentration is regulated, two mechanisms of vitamin transport were characterized. Ascorbate is transported as such by carriers that are sodium-dependent, saturable, energy-dependent, and inhibited by newly synthesized ascorbate analogs. The two human ascorbate transporters hSVCT1 and hSVCT2 were cloned and characterized, and genomic characterization and studies of nucleotide polymorphisms are underway. In contrast, the oxidized form of vitamin C, dehydroascorbic acid, is transported by glucose transporters GLUT I, III, and IV, and immediately reduced intracellularly to ascorbate. The protein responsible for reduction in neutrophils was isolated, sequenced, identified as thioltransferase (glutaredoxin), and cloned. The full-length human glutaredoxin gene was cloned and its promoter characterized. These studies indicate that vitamin C function in neutrophils may be to protect neutrophils from their own oxidants. Overall findings suggest that vitamin C function can be determined in relation to its concentration in living tissues. The clinical goals of in situ kinetics are to determine
how vitamin concentrations are achieved in normal humans as
a function of dose and whether concentrations humans achieve
are those that regulate molecular functions of the vitamin.
An extensive clinical study was completed in healthy male inpatients
hospitalized at the Clinical Center. For the first time, the
following were described: the relationship between vitamin
C doses over a wide range and its concentration in plasma and
tissues; true bioavailability of vitamin C; vitamin urinary
excretion in relation to dose; and potential adverse effects
in relation to dose. A clinical study in healthy women is underway. Publications 1. Rumsey SC, Daruwala R, Al-Hasani H, Zarnowski M, Simpson IA, Levine M. Dehydroascorbic acid transport by GLUT4 in Xenopus oocytes and isolated rat adipocytes. Journal of Biological Chemistry(275): 28246-28253, 2000. [ Full Text/Abstract] 2. Daruwala R, Song J, Koh WS, Rumsey SC, Levine M. Cloning and functional characterization of the human sodium-dependent vitamin C transporters hSVCT1 and hSVCT2. FEBS Letters (460): 480-484, 1999. [ Full Text/Abstract] 3. Levine M, Rumsey SC, Daruwala R, Park JB, Wang Y. Criteria and recommendations for vitamin C intake. Journal of the American Medical Association(281): 1415-1423, 1999. [ Full Text/Abstract] 4. Rumsey SC, Welch RW, Garraffo HM, Ge P, Lu S-F, Crossman AT, Kirk KL, Levine M. Specificity of ascorbate analogs for ascorbate transport: synthesis and detection of [125I]-6-deoxy-6-iodo-L-ascorbic acid and characterization of its ascorbate-specific transport properties. Journal of Biological Chemistry(274): 23215-23222, 1999. [ Full Text/Abstract] |
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Liver
Diseases Branch , Chief |
B.A., Harvard College, 1980 Research Statement Hepatitis B (HBV) and C (HCV) viruses are the leading causes of chronic liver diseases in the world. Chronic infection with these viruses has been linked to the development of hepatocellular carcinoma, a major leading cause of death from cancer worldwide. The overall goals of our laboratory are to understand the basic mechanisms of hepatocellular injury, recovery from viral infection, persistent infection, progression of disease, and development of hepatocellular carcinoma. Other research efforts are directed at molecular strategies for vaccine and antiviral development and animal models of viral hepatitis. Publications 1. Promrat K Lutchman G Uwaifo GI Freedman RJ Soza A Heller T Doo E Ghany M Premkumar A Park Y Liang TJ Yanovski JA Kleiner DE Hoofnagle JH A pilot study of pioglitazone treatment for nonalcoholic steatohepatitis. Hepatology (39): 188-96 , 2004. [ Full Text/Abstract] 2. Rahman F Heller T Sobao Y Mizukoshi E Nascimbeni M Alter H Herrine S Hoofnagle J Liang TJ Rehermann B Effects of antiviral therapy on the cellular immune response in acute hepatitis C. Hepatology (40): 87-97 , 2004. [ Full Text/Abstract] 3. Cai Z Liang TJ Luo G Effects of mutations of the initiation nucleotides on hepatitis C virus RNA replication in the cell. J Virol (78): 3633-43 , 2004. [ Full Text/Abstract] 4. Keck ZY Sung VM Perkins S Rowe J Paul S Liang TJ Lai MM Foung SK Human monoclonal antibody to hepatitis C virus E1 glycoprotein that blocks virus attachment and viral infectivity. J Virol (78): 7257-63 , 2004. [ Full Text/Abstract] ] |
Constantine Londos, D.D.S., Ph.D. Membrane Regulation Section, Chief |
D.D.S., The Ohio State University, 1963 Research Statement All cells package neutral lipids in discrete storage droplets that are characterized by unique surface proteins. In adipose cells, the enormous droplets contain triacylglycerols, the primary bodily energy stores, whereas in steroidogenic cells, much smaller droplets contain cholesteryl esters, the precursors for steroid hormone synthesis. In the general cell population, available fatty acids are captured in even smaller droplets and are used eventually as energy sources or for membrane remodeling. The adipocyte remains our primary model system, and we focus on the processes whereby hormones regulate both the packaging and hydrolysis of stored neutral lipids. Obesity is characterized by a surfeit of stored adipose lipids, and the wasting syndrome, cachexia, is associated with a marked loss of these important energy stores. Moreover, type 2 diabetes (NIDDM, adult onset) is characterized by elevated plasma fatty acids, which are thought to result from unchecked lipolysis in adipose cells. Current evidence indicates that suppression of this lipolytic response ameliorates many of the symptoms associated with type 2 diabetes. Our fundamental approach to the questions, outlined below, involves manipulation of cultured cell systems using molecular biological tools complemented with biochemical and cellular biological techniques. We also employ transgenesis and knock out technology. One important goal is to dissect the molecular events subsequent to stimulation of adipose cells by lipolytic and antilipolytic hormones, such as epinephrine and insulin, respectively. Stimulation by catecholamines involves activation of adenylyl cyclase, elevation of cAMP, and activation protein kinase A. Hormone-sensitive lipase, the rate-limiting enzyme of lipolysis, is phosphorylated by protein kinase A. Although the structure and PKA phosphorylation sites of HSL are known, there is little information on the process whereby cytoplasmic HSL gains access to its substrate, the triacylglycerols housed within the lipid storage droplets. We have found that activated HSL rapidly translocates and adheres to the surface of lipid droplets, but nothing is known of its cytoplasmic location in unstimulated cells, the translocation process, or the target locus on the droplet surface. A number of approaches are aimed at dissecting this process, including (1) construction of a fusion library for identifying possible HSL binding proteins; (2) use of retroviral systems to introduce HSL constructs that encode a variety of mutagenized forms, especially those in which the various phosphorylation sites are mutated either singly or in combination; and (3) identification of lipolytic inhibitors that act downstream of PKA activation. To this end, in collaboration with a biotech company we have established a screening system that has identified compounds that are both strongly antilipolytic and exhibit considerable efficacy in reversing a number of symptoms in diabetic animal models. Such compounds are not only useful in our biochemical research but also represent potential therapeutic agents. An important, but largely overlooked, component in the lipolytic
equation is the lipid droplet. Previously thought to be merely
an amorphous accumulation of neutral lipids, we have discovered
a family of proteins, termed perilipins, that are found exclusively
at lipid droplet surfaces. Perilipin is a single copy gene
that gives rise, by alternative splicing, to three isoforms,
A, B, and C. The perilipin gene is expressed most strongly
in adipose cells where the A and B isoforms coat the triacylglycerol-containing
droplets. The gene is expressed also in steroidogenic cells
where perilipins A and C coat the cholesteryl ester-containing
droplets. Like adipocytes, steroidogenic cells use a cAMP stimulated
process and an HSL-like enzyme to release cholesterol, which
serves as a substrate for steroid hormone synthesis. Perilipins
are polyphosphorylated by PKA and, thus, their occurrence in
only those cells in which lipolysis is mediated by increased
cAMP points to a role for perilipin in the process of lipid
breakdown. We have found that a related protein, adipose differentiation-related
protein (ADRP), also termed adipophilin, coats the lipid droplet
in all other cells. However, expression of perilipin in fibroblastic
cells leads to the disappearance of ADRP, after which the lipid
droplets acquire a coating of perilipin. The non-phosphorylated
perilipin exerts a protective effect and suppresses lipolysis
in such cells. Upon activation of PKA and subsequent phosphorylation
of perilipin, a robust lipolysis ensues, which is due solely
to perilipin phosphorylation, since the fibroblastic cells
contain no PKA-mediated lipases. A further manifestation of
the protective effect of non-phosphorylated perilipin is the
normal deposition of fat reserves in adipose tissue. We found
that the perilipin null mouse had a 70% decrease adipose
tissue, but are of normal weight and have similar caloric intake
as wild type mice. Oddly, despite their greatly diminished
adipose tissue, these animals have elevated plasma leptin values. Publications 1. Tansey JT Huml AM Vogt R Davis KE Jones JM Fraser KA Brasaemle DL Kimmel AR Londos C Functional studies on native and mutated forms of perilipins. A role in protein kinase A-mediated lipolysis of triacylglycerols. J Biol Chem (278): 8401-6 , 2003. [ Full Text/Abstract] 2. Su CL Sztalryd C Contreras JA Holm C Kimmel AR Londos C Mutational analysis of the hormone-sensitive lipase translocation reaction in adipocytes. J Biol Chem (278): 43615-9 , 2003. [ Full Text/Abstract] 3. Sztalryd C Xu G Dorward H Tansey JT Contreras JA Kimmel AR Londos C Perilipin A is essential for the translocation of hormone-sensitive lipase during lipolytic activation. J Cell Biol (161): 1093-103 , 2003. [ Full Text/Abstract] |
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Transplantation
and Autoimmunity Branch , Investigator |
Ph.D., State University of New York, Albany, New York, 1984 Research Statement Transplantation of pancreatic islets can provide a long-term insulin independence for types I diabetics. The islets necessary for this procedure are obtained from cadaveric pancreata and therefore are in a short supply. In principle, this problem could be overcome by generating new islets ex vivo from pancreatic stem and progenitor cells. Alternatively and in addition, strategies allowing controlled expansion of already differentiated islet cell types can also be employed for generation of endocrine hormone-producing cells. We have recently developed a strategy for in vitro differentiation of pluripotent murine embryonic stem (ES) cells into insulin-producing islet-like cell clusters. We are now extending this work to cultures of adult pancreas. When cultured on adhesive substrates adult islets sprout an actively proliferating cell population. During the course of the culture, these cells aggregate to form new three-dimensional cell clusters and begin to express insulin. Glucagon and somatostatin-expressing cells are also generated. We are using these embryonic and adult in vitro systems for addressing questions of pancreatic cell development and for designing strategies for generation of physiologically competent pancreatic islets for possible future use in transplantation. Publications 1. Kim JH Auerbach JM Rodriguez-Gomez JA Velasco I Gavin D Lumelsky N Lee SH Nguyen J Sanchez-Pernaute R Bankiewicz K McKay R Dopamine neurons derived from embryonic stem cells function in an animal model of Parkinson's disease. Nature (418): 50-6 , 2002. [ Full Text/Abstract] 2. Lumelsky N. Pancreatic differentiation of pluripotent stem cells. Book chapter in Human embryonic stem cells. Humana Press, Inc., 2002. [In Press] 3. Lumelsky N Blondel O Laeng P Velasco I Ravin R McKay R Differentiation of embryonic stem cells to insulin-secreting structures similar to pancreatic islets. Science (292): 1389-94 , 2001. [ Full Text/Abstract] 4. Lee SH Lumelsky N Studer L Auerbach JM McKay RD Efficient generation of midbrain and hindbrain neurons from mouse embryonic stem cells. Nat Biotechnol (18): 675-9 , 2000. [ Full Text/Abstract] |
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Transplantation
Branch |
Biographical Sketch Education Research Statement Despite dramatic improvements in acute rejection rates and short term graft survival, long term graft loss remains a significant problem after kidney transplantation. The leading cause of late graft loss is chronic allograft nephropathy (CAN). This disease can occur months to years after transplantation, and is manifested by a progressive decline in graft function, protein in the urine, and hypertension. The etiology of this disorder is multifactorial and includes both immunologic and non-immunologic etiologies. Moreover, there are no specific therapies for CAN beyond controlling blood pressure and cholesterol levels, similar to other forms of kidney failure. Our research program utilizes a series of rat and kidney models of kidney and heart transplantation to study the cellular, molecular, and physiologic events following transplantation. By manipulating the donor and recipient combinations, we have found that recipient and donor matching can alter graft the course of CAN. Further, we have detected the expression of a number of genes for new growth factors that are elevated in these models. We have used these models as platforms for study in our human patients following kidney transplantation. Similar to our findings in mice, we are detecting elevated levels of these growth factors, prior to the development of clinical disease. We are also investigating the role of BK polyomavirus infection,
following kidney transplantation in altering graft outcomes
by studying the molecular and cellular events of infection,
and how they may contribute to graft scaring (fibrosis). To
date, this work has resulted in a critical surveillance program
to monitor recipients before and after transplantation to avoid
infection of the graft with BK polyomavirus. Publications 1. Mannon RB Polyomavirus nephropathy: what have we learned? Transplantation (77): 1313-8 , 2004. [ Full Text/Abstract] 2. Franceschini N Cheng O Zhang X Ruiz P Mannon RB Inhibition of prolyl-4-hydroxylase ameliorates chronic rejection of mouse kidney allografts. Am J Transplant (3): 396-402 , 2003. [ Full Text/Abstract] 3. Mannon RB Griffiths R Ruiz P Platt JL Coffman TM Absence of donor MHC antigen expression ameliorates chronic kidney allograft rejection. Kidney Int (62): 290-300 , 2002. [ Full Text/Abstract] 4. Li RM Mannon RB Kleiner D Tsokos M Bynum M Kirk AD Kopp JB BK virus and SV40 co-infection in polyomavirus nephropathy. Transplantation (74): 1497-504 , 2002. [ Full Text/Abstract] |
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Mechanisms of Gene Regulation Section, Chief |
B.S., Charles University Czech Republic, 1961 Research Statement Biology of nuclear receptors. Publications 1. Castillo SO Baffi JS Palkovits M Goldstein DS Kopin IJ Witta J Magnuson MA Nikodem VM Dopamine biosynthesis is selectively abolished in substantia nigra/ventral tegmental area but not in hypothalamic neurons in mice with targeted disruption of the Nurr1 gene. Mol Cell Neurosci (11): 36-46 , 1998. [ Full Text/Abstract] 2. Huo B Dozin B Nikodem VM Identification of a nuclear protein from rat developing brain as heterodimerization partner with thyroid hormone receptor-beta. Endocrinology (138): 3283-9 , 1997. [ Full Text/Abstract] 3. Castillo SO Xiao Q Lyu MS Kozak CA Nikodem VM Organization, sequence, chromosomal localization, and promoter identification of the mouse orphan nuclear receptor Nurr1 gene. Genomics (41): 250-7 , 1997. [ Full Text/Abstract] 4. Hallenbeck PL Minucci S Lippoldt R Phyillaier |
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Liver
Diseases Branch , Investigator |
Biographical Sketch MD, Medizinische Hochschule, Hannover, Germany, 1991
Research Statement Our group studies the immunology of viral hepatitis B and C, the most common forms of liver disease that affects more than 500 million people worldwide. The spectrum of disease ranges from acute to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The clinical course of disease not only reflects the biologic properties and pathogenicity of these two hepatitis viruses, but is the result of the specific interaction between each virus and the immune system of the infected host. In addition to virus-specific antibodies, T cells are considered key players in the defense against these viruses, because of their ability to recognize viral antigens in and to eliminate virus from infected cells. However, once chronic infection is established, the virus specific immune response seems to be unable to terminate persistent infection in most cases and, instead, contributes to liver injury and chronic hepatitis. Our group focuses on the role of the virus specific immune response in viral clearance as well as disease pathogenesis using multidisciplinary approaches that include research with infected patients, transgenic mice, and infectious animal models. Publications 1. Racanelli V Behrens SE Aliberti J Rehermann B Dendritic cells transfected with cytopathic self-replicating RNA induce crosspriming of CD8+ T cells and antiviral immunity. Immunity (20): 47-58 , 2004. [ Full Text/Abstract] 2. Nascimbeni M Rehermann B Determination of hepatitis B virus-specific CD8+ T-cell activity in the liver. Methods Mol Med (96): 65-83 , 2004. [ Full Text/Abstract] 3. Rahman F Heller T Sobao Y Mizukoshi E Nascimbeni M Alter H Herrine S Hoofnagle J Liang TJ Rehermann B Effects of antiviral therapy on the cellular immune response in acute hepatitis C. Hepatology (40): 87-97 , 2004. [ Full Text/Abstract] 4. Rahman F Rehermann B Ethnicity and hepatitis C virus infection. Clin Gastroenterol Hepatol (2): 456-8 , 2004. [ Full Text/Abstract]
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| Robert Star, M.D.
Renal Diagnostics and Therapeutics Section, Chief |
B.A., Harvard, 1976 Research Statement The morbidity and mortality of acute renal failure (ARF) have remained high despite numerous attempts at novel therapies. Many agents have worked in animals but failed in clinical trials. Effective treatment likely requires early detection and a better understanding of the pathophysiology of human ARF. Our long_term goals are to find markers to detect ARF and to therapies to treat and prevent ARF. We have recently found: Therapeutics: Whereas many agents can prevent experimental renal injury when started before the insult, only a few agents are capable of treating ARF in animals. We found that the anti-inflammatory cytokines alpha_melanocyte stimulating hormone (MSH) and interleukin-10 (IL-10) inhibit renal injury in mouse ischemia and cisplatin injury models. "-MSH decreases injury even when given 6 hrs after ischemia; IL-10 is effective when started 1 hr after cisplatin. We initiated a Phase 1 safety trial of "-MSH at UT-Southwestern. Single doses of "-MSH (at levels used in the animal experiments) were safe; the only side effect was that "-MSH increased blood pressure, which might be helpful in ARF. "-MSH inhibits key maladaptive steps such as leukocyte infiltration, induction of IL_8, ICAM_1, inducible NO synthase, activation of Nf-kB and the p38 MAP kinase pathway. Unfortunately, neither "-MSH nor IL-10 protect against mercuric chloride nephrotoxic ARF in mice. However, we recently found that DMSO inhibits mercuric chloride nephrotoxicity, even when DMSO is started 4 hrs after mercury. Detection of ARF: ARF is diagnosed by a progressive
rise in serum creatinine over several days. However, patients
are typically volume overloaded which dilutes creatinine and
delays diagnosis. Therapeutic agents must be started early;
therefore, early detection is critical. By RNA subtraction,
we found that one gene, cyr61, was markedly increased 2 hrs
in proximal straight tubules but not in other organs after
renal ischemia. Cyr61 protein was increased in mouse and rat
kidneys within 1 hr, and was detected in urine at 3-6 hrs after
ischemia. Cyr61 was not detected volume depletion, which is
often difficult to differentiate from ARF. We hypothesize that
cyr61, a secreted growth factor-inducible immediate early gene,
is rapidly induced in proximal tubules following ischemia and
excreted in the urine. Urinary cyr61 might detect subtle renal
injury after chemotherapy, transplantation, vascular surgery,
multi-organ failure, or in kidney donors. Publications 1. Miyaji T Hu X Star RA alpha-Melanocyte-simulating hormone and interleukin-10 do not protect the kidney against mercuric chloride-induced injury. Am J Physiol Renal Physiol (282): F795-801 , 2002. [ Full Text/Abstract] 2. Muramatsu Y Tsujie M Kohda Y Pham B Perantoni AO Zhao H Jo SK Yuen PS Craig L Hu X Star RA Early detection of cysteine rich protein 61 (CYR61, CCN1) in urine following renal ischemic reperfusion injury. Kidney Int (62): 1601-10 , 2002. [ Full Text/Abstract] 3. Miyaji T Hewitt SM Liotta LA Star RA Frozen protein arrays: a new method for arraying and detecting recombinant and native tissue proteins. Proteomics (2): 1489-93 , 2002. [ Full Text/Abstract] 4. Star R Hostetter T Hortin GL New markers for kidney disease. Clin Chem (48): 1375-6 , 2002. [ Full Text/Abstract]
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Laboratory
of Molecular and Cellular Biology |
B.S., Natal, South Africa, 1980 Research Statement Fragile X syndrome and Friedreich's ataxia These diseases are interesting not only because they provide a window into critical processes such as learning and memory, but also because there is evidence to suggest that some aspects of disease pathology may involve novel mechanisms including defects in transcription elongation and RNA toxicity. We are using a number of approaches to look at both the mechanism of expansion and the consequences of expansion in these two disorders. These include biochemical studies of the unusual nucleic acid structures formed by disease associated trinucleotide repeats, and the development of various in vitro, bacterial, tissue culture, and transgenic animal models for different aspects of these diseases. This may ultimately allow us to develop rational approaches to the prevention or treatment of this group of genetic disorders. Publications 1. Grabczyk E Kumari D Usdin K Fragile X syndrome and Friedreich's ataxia: two different paradigms for repeat induced transcript insufficiency. Brain Res Bull (56): 367-73 , 2001. [ Full Text/Abstract] 2. Kumari D Usdin K Interaction of the transcription factors USF1, USF2, and alpha -Pal/Nrf-1 with the FMR1 promoter. Implications for Fragile X mental retardation syndrome. J Biol Chem (276): 4357-64 , 2001. [ Full Text/Abstract] |
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Kidney Disease Section, Senior Investigator |
M.D., Freiburg ( Germany), 1962 Research Statement The general aim of our research is to study renal mechanisms of extracellular fluid volume homeostasis and blood pressure regulation. The laboratory focuses specifically on the role of the juxtaglomerular apparatus, an intrarenal control mechanism that regulates the renin-angiotensin system and renal vascular tone through tubuloglomerular feedback. The role of specific gene products involved in juxtaglomerular signal transmission is studied in transgenic mouse models. Current work focuses on the roles of the angiotensin 1A receptor, adenosine 1 receptor, neuronal and endothelial nitric oxide synthases, phospholipase A2, and cyclooxygenase-2 in control of renin gene expression and renin secretion as well as renal hemodynamic and transport functions using knockout mice. Special emphasis is on the role of purinergic signal transmission through ATP, AMP, and adenosine using mice with deletions of ecto-nucleotidase, adenosine deaminase, NTPDases, and nucleoside transporters. Furthermore, the laboratory uses knockout mice to study the
effects of deficiencies in specific renal transporters or transport
regulators on renal and systemic functions as models for fluid
and electrolyte disturbances caused by loss or gain of function
mutations in humans. Current work focuses on the effects of
Na/H exchanger and its regulation by angiotensin II, ROMK,
and K and Cl channel knockouts on fluid and ion transport rates
in the proximal tubule and loop of Henle. Another project aims
at the generation and characterization of mice with NKCC2 knockout
mutations that are specific for the threee major isoforms of
this transporter (A,B, or F). Publications 1. Hashimoto S Huang Y Mizel D Briggs J Schnermann J Compensation of proximal tubule malabsorption in AQP1-deficient mice without TGF-mediated reduction of GFR. Acta Physiol Scand (181): 455-62 , 2004. [ Full Text/Abstract] 2. Castrop H Huang Y Hashimoto S Mizel D Hansen P Theilig F Bachmann S Deng C Briggs J Schnermann J Impairment of tubuloglomerular feedback regulation of GFR in ecto-5''-nucleotidase/CD73-deficient mice. J Clin Invest (114): 634-42 , 2004. [ Full Text/Abstract] 3. Castrop H Schweda F Mizel D Huang Y Briggs J Kurtz A Schnermann J Permissive role of nitric oxide in macula densa control of renin secretion. Am J Physiol Renal Physiol (286): F848-57 , 2004. [ Full Text/Abstract] 4. Hansen PB Castrop H Briggs J Schnermann J Adenosine induces vasoconstriction through Gi-dependent activation of phospholipase C in isolated perfused afferent arterioles of mice. J Am Soc Nephrol (14): 2457-65 , 2003. [ Full Text/Abstract] |
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Molecular Pathophysiology Section, Chief |
B.A., Columbia, 1967 Research Statement My research has focused primarily on G protein-mediated signal transduction. My lab has identified naturally occurring mutations in G protein alpha subunits and in G protein-coupled receptors in human diseases, particularly endocrine disorders. Germline loss of function mutations in the ubiquitously expressed Gs-alpha gene that couples numerous receptors to stimulation of cAMP formation have been identified as the cause of generalized hormone resistance and dysmorphic features in the inherited disorder pseudohypoparathyroidism type Ia. Somatic gain of function mutations in Gs-alpha have been identified as the cause of the McCune-Albright syndrome, a sporadic disorder in which affected individuals have varying combinations of endocrine hyperfunction, café-au-lait skin pigmentation, and polyostotic fibrous dysplasia. We have also identified and studied the consequences of germline loss- and gain-of-function mutations in G protein coupled receptor genes, e.g. inactivating mutations of the V2 vasopressin receptor gene in subjects with nephrogenic diabetes insipidus. In particular, we have recently focused on the structure and function of a G protein-coupled calcium-sensing receptor that plays a central role in extracellular calcium homeostasis. We have generated a panel of monoclonal antibodies to the extracellular domain of this receptor that have proved useful in defining functional features. We are also doing detailed expression studies of naturally occurring, activating receptor mutants. We have identified the cysteine residues responsible for receptor dimerization, and we have begun to define the role of dimerization in receptor activation. Our goal is to understand how calcium binding to the receptor leads to receptor and G protein activation, and to identify sites on the receptor extracellular domain that could serve as targets for therapeutic intervention in disorders such as hyperparathyroidism. Finally, we also collaborate with other investigators in the NIDDK Metabolic Diseases Branch and in NHGRI on studies of the multiple endocrine neoplasia type 1 (MEN1) gene. After the successful positional cloning of the gene, we are pursuing a wide-ranging series of studies to elucidate its structure and function. The sequence of this 610 amino acid protein, menin, shows no similarity to other known proteins and does not contain defined functional motifs. Recent work shows, however, that menin is localized to the nucleus. We expect that ongoing studies will provide insights into menin's function and provide an opportunity to test the consequences of the many different germline mutations that have already been identified in subjects with MEN1 and somatic mutations identified in sporadic endocrine tumors. Indeed, we have generated conventional and conditional mouse knockout models that recapitualte all the features of the human disease, including pituitary, parathyroid, and pancreatic islet tumors. Publications 1. Spiegel AM Weinstein LS Inherited diseases involving g proteins and g protein-coupled receptors. Annu Rev Med (55): 27-39 , 2004. [ Full Text/Abstract] 2. Hu J Spiegel AM Naturally occurring mutations of the extracellular Ca2+-sensing receptor: implications for its structure and function. Trends Endocrinol Metab (14): 282-8 , 2003. [ Full Text/Abstract] 3. Crabtree JS Scacheri PC Ward JM McNally SR Swain GP Montagna C Hager JH Hanahan D Edlund H Magnuson MA Garrett-Beal L Burns AL Ried T Chandrasekharappa SC Marx SJ Spiegel AM Collins FS Of mice and MEN1: Insulinomas in a conditional mouse knockout. Mol Cell Biol (23): 6075-85 , 2003. [ Full Text/Abstract] 4. Libutti SK Crabtree JS Lorang D Burns AL Mazzanti C Hewitt SM O''Connor S Ward JM Emmert-Buck MR Remaley A Miller M Turner E Alexander HR Arnold A Marx SJ Collins FS Spiegel AM Parathyroid gland-specific deletion of the mouse Men1 gene results in parathyroid neoplasia and hypercalcemic hyperparathyroidism. Cancer Res (63): 8022-8 , 2003. [ Full Text/Abstract] |
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Metabolic
Diseases Branch , Senior Investigator |
B.S., Massachusetts Institute of Technology, 1979 Research Statement Our laboratory studies the genetic regulation, biochemistry, and physiological roles of the heterotrimeric G protein Gs, which is required for hormone-stimulated intracellular cAMP accumulation. Using the human genetic model Albright hereditary osteodystrophy (AHO), which is associated with heterozygous inactivating mutations in the Gs alpha-subunit gene (GNAS), and a mouse model with heterozygous inactivation of Gnas, we have demonstrated that Gs-alpha is imprinted in a tissue-specific manner with the paternal allele poorly expressed in some tissues. This most likely explains why maternal transmission of AHO leads to multihormone resistance while paternal transmission does not. By examining naturally occurring AHO mutations, we have identified amino acid residues in Gs-alpha that are required for normal guanine nucleotide binding, activation, and inactivation. The phenotype of the Gnas knockout mice suggests that this gene plays a major role in many developmental and metabolic processes, including the regulation of energy metabolism and insulin action. Present studies in additional germline and tissue-specific knockout lines are examining the roles of Gs-alpha and other Gnas gene products in these processes and the mechanism by which Gs-alpha is imprinted in a tissue-specific manner. Studies in mouse models and patients with isolated parathyroid hormone resistance (pseudohypoparathyroidism type 1B) have identified a region important for Gs-alpha imprinting, and studies are ongoing to define the mechanisms involved. Publications 1. Chen M Haluzik M Wolf NJ Lorenzo J Dietz KR Reitman ML Weinstein LS Increased Insulin Sensitivity in Paternal Gnas Knockout Mice is Associated with Increased Lipid Clearance. Endocrinology , 2004. [ Full Text/Abstract] 2. Spiegel AM Weinstein LS Inherited diseases involving G proteins and G protein-coupled receptors. Annu Rev Med(55): 27-39, 2004. [ Full Text/Abstract] |
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Molecular Signaling Section, Chief |
B.S., University of Frankfurt, Germany, 1982 Research Statement My laboratory pursues two different lines of work that deal with the molecular, biochemical, and physiological analysis of muscarinic acetylcholine receptors and other G protein-coupled receptors. 1. DELINEATION OF MOLECULAR MECHANISMS GOVERNING SIGNALING
THROUGH G PROTEIN-COUPLED RECEPTORS 2. GENERATION AND ANALYSIS OF RECEPTOR KNOCK-OUT MICE Publications 1. Wess J Novel insights into muscarinic acetylcholine receptor function using gene targeting technology. Trends Pharmacol Sci (24): 414-20 , 2003. [ Full Text/Abstract] 2. Schmidt C Li B Bloodworth L Erlenbach I Zeng FY Wess J Random mutagenesis of the M3 muscarinic acetylcholine receptor expressed in yeast. Identification of point mutations that J Biol Chem (278): 30248-60 , 2003. [ Full Text/Abstract] |
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Digestive
Diseases Branch , Senior Investigator |
B.A., Duke University, 1974 Research Statement Molecular and cellular biology of brain and gastrointestinal hormones and their receptors. Special interest in the receptors for cholecystokinin and gastrin; pituitary adenylate cyclase activated polypeptide and calcitonin gene related peptide. |
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Transplantation
and Autoimmunity Branch , Chief |
B.S., University of Michigan, 1977 Research Statement Dr. David Harlan is interested in identifying the immunological mechanisms that underlie the pathogenesis of type 1 diabetes mellitus (T1DM) and/or the rejection organs/tissues transplanted to treat that disease. To those ends, his group utilizes molecular, cellular, and small animal models to elucidate immunological mechanisms. In addition, he is actively involved in clinical protocols to test whether immune modifying reagents can ameliorate disease severity in individuals with recently diagnosed T1DM, and to transplant pancreatic islets into individuals with long standing and "brittle" T1DM. For the latter, he and his colleagues have developed a non-human primate model to test novel approaches to improve islet transplant technology. Publications 1. Pechhold K Patterson NB Blum C Fleischacker CL Boehm BO Harlan DM Low dose streptozotocin-induced diabetes in rat insulin promoter-mCD80-transgenic mice is T cell autoantigen-specific and CD28 dependent. J Immunol (166): 2531-9 , 2001. [ Full Text/Abstract] 2. Blair PJ Riley JL Harlan DM Abe R Tadaki DK Hoffmann SC White L Francomano T Perfetto SJ Kirk AD June CH CD40 ligand (CD154) triggers a short-term CD4(+) T cell activation response that results in secretion of immunomodulatory cytokines and apoptosis. J Exp Med (191): 651-60 , 2000. [ Full Text/Abstract] |
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Molecular and Cell Biology Section, Chief |
B.A., University of California, Berkeley, 1970 Research Statement The role of cytokines in maintaining stem/progenitor cell characteristics is being investigated. Molecular structure and processing related to cellular function, differentiation, and development are studied using molecular and cell biology, biochemical, and biophysical approaches. Emphasis is on transcriptional regulation and models of proliferation and differentiation including stem cell marking studies and transplantation with particular interest in the function of the erythropoietin receptor and stress response in hematopoietic, neuronal, muscle, endothelial and other stem/progenitor cells. Other studies include differential globin gene expression related to the pathophysiology of sickle cell disease and other hemoglobinopathies. Publications 1. Haley JD Smith DE Schwedes J Brennan R Pearce C Moore C Wang F Petti F Grosveld F Jane SM Noguchi CT Schechter AN Identification and characterization of mechanistically distinct inducers of gamma-globin transcription. Biochem Pharmacol (66): 1755-68 , 2003. [ Full Text/Abstract] 2. Yu X Shacka JJ Eells JB Suarez-Quian C Przygodzki RM Beleslin-Cokic B Lin CS Nikodem VM Hempstead B Flanders KC Costantini F Noguchi CT Erythropoietin receptor signalling is required for normal brain development. Development (129): 505-16 , 2002. [ Full Text/Abstract] 3. Yu X Lin CS Costantini F Noguchi CT The human erythropoietin receptor gene rescues erythropoiesis and developmental defects in the erythropoietin receptor null mouse. Blood (98): 475-7 , 2001. [ Full Text/Abstract] 4. Ogilvie M Yu X Nicolas-Metral V Pulido SM Liu C Ruegg UT Noguchi CT Erythropoietin stimulates proliferation and interferes with differentiation of myoblasts. J Biol Chem (275): 39754-61 , 2000. [ Full Text/Abstract]
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Genetics
of Development and Disease Branch , Chief |
B.S., Bates College, 1976 Research Statement Sphingolipids are emerging as important mediators and regulators of cell signaling pathways. Our studies have focused on the actions of two classes of sphingolipids represented by glycosphingolipids and sphingosine-1-phosphate. Our work is aimed at defining the normal functions of these sphingolipids and understanding their roles in disease processes. Glycosphingolipids (GSLs) are found in the outer leaflet
of the plasma membrane and are concentrated in specialized
signaling structures called rafts. They are particularly abundant
in neuronal cells in the form of gangliosides (sialic acid
containing GSLs). Through genetic disruption of genes that
encode synthetic enzymes for GSLs, we have created a series
of mice that express limited glycosphingolipid structures.
We are using these mice to discover the function of GSLs.
Publications 1. Proia RL Wu YP Blood to brain to the rescue. J Clin Invest (113): 1108-10 , 2004. [ Full Text/Abstract] 2. Wu YP Proia RL Deletion of macrophage-inflammatory protein 1 alpha retards neurodegeneration in Sandhoff disease mice. Proc Natl Acad Sci U S A (101): 8425-30 , 2004. [ Full Text/Abstract] 3. Allende ML Dreier JL Mandala S Proia RL Expression of the sphingosine 1-phosphate receptor, S1P1, on T-cells controls thymic emigration. J Biol Chem (279): 15396-401 , 2004. [ Full Text/Abstract] 4. Matloubian M Lo CG Cinamon G Lesneski MJ Xu Y Brinkmann V Allende ML Proia RL Cyster JG Lymphocyte egress from thymus and peripheral lymphoid organs is dependent on S1P receptor 1. Nature (427): 355-60 , 2004. [ Full Text/Abstract]
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Molecular
and Clinical Hematology Branch , Chief |
B.S., Brown, 1976 Research Statement Molecular and Clinical Hematology Branch Molecular Hematology Section Publications 1. Steinberg MH Rodgers GP Pharmacologic modulation of fetal hemoglobin. Medicine ( Baltimore) (80): 328-44 , 2001. [ Full Text/Abstract] 2. Tang DC Fucharoen S Ding I Rodgers GP Rapid differentiation of five common alpha-thalassemia genotypes by polymerase chain reaction. J Lab Clin Med (137): 290-5 , 2001. [ Full Text/Abstract] 3. Drew LR Tang DC Berg PE Rodgers GP The role of trans-acting factors and DNA-bending in the silencing of human beta-globin gene expression. Nucleic Acids Res (28): 2823-30 , 2000. [ Full Text/Abstract |
