Many vital organs, including the kidney, form as a result of a mesenchymal-epithelial interaction. A mediator of these interactions is hepatocyte growth factor, a. k. a. scatter factor, (HGF SF). HGFISF is mesenchymally-derived growth factor and ligand for the epithelial c- rnet receptor. Though HGFISF is not the only inducer of renal development and tubulogenesis, it induces tubulogenesis both in vivo and in vitro ii Madin-Darby canine kidney (MDCK) cells, which are derived from canine renal tubular epithelium. Generation and maintenance of cell polarity is essential to epithelial cell function. To establish and maintain their polarity, epithelial, including MDCK, cells must send plasma membrane (PM) proteins to th( correct apical or basolateral PM. Preliminary results show that when HGF/SF induced tubulogenesis occurs MDCK cells lose their polarity as they branch out and then regain their polarity as the new tubules form. A major discovery in recent years is that almost all intracellular membrane traffic uses a common machinery for membrane fusion. Syntaxins are a gene family and component of the membrane fusion machinery that appear to specify correct delivery to the different PM surfaces. Syntaxins 2, 3, and 4 are abundant in epithelial organs, e.g. kidney. Syntaxins 2, 3, and 4 were found to be differentially expressed in MDCK cells, with syntaxins 3 and 4 having a completely non- overlapping distribution. Syntaxins are the first molecules that are part of the membrane fusion machinery, whose isoforms are differentially localized and whose overexpression has differential effects on polarized membrane traffic. Hence, they are the leading candidates for containing at least part of the information needed for the maintenance of cell polarity. The hypothesis is that transient loss of cell polarity i crucial for renal tubulogenesi: and syntaxins are involved in controlling cell poladty and therefore tubulogenesis. The expression and localization of syntaxins will be examined during HUF/SF induced tubulogenesis in MDCK cells, normal development of rodent kidneys, and abnormal development in disease states such a polycystic kidney disease and renal cell carcinoma. To directly test the hypothesis, the expression an function of different syntaxins will be perturbed by overexpression, inhibition of expression, and dominar negative mutants. If the expression of syntaxins is important for tubulogenesis, consideration can be given t finding ways to alter syntaxin expression in disease states, perhaps by gene therapy using viral vectors.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08DK002509-02
Application #
2733834
Study Section
Special Emphasis Panel (SRC)
Program Officer
Bishop, Terry Rogers
Project Start
1997-09-15
Project End
2002-06-30
Budget Start
1998-07-31
Budget End
1999-06-30
Support Year
2
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of California San Francisco
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Rogers, Katherine K; Wilson, Patricia D; Snyder, Richard W et al. (2004) The exocyst localizes to the primary cilium in MDCK cells. Biochem Biophys Res Commun 319:138-43
Berman, Elisheva; Merz, Jon F; Rudnick, Michael et al. (2004) Religiosity in a hemodialysis population and its relationship to satisfaction with medical care, satisfaction with life, and adherence. Am J Kidney Dis 44:488-97
Rogers, Katherine K; Jou, Tzuu-Shuh; Guo, Wei et al. (2003) The Rho family of small GTPases is involved in epithelial cystogenesis and tubulogenesis. Kidney Int 63:1632-44
Smyth, Brendan J; Snyder, Richard W; Balkovetz, Daniel F et al. (2003) Recent advances in the cell biology of polycystic kidney disease. Int Rev Cytol 231:51-89
Mangravite, L M; Lipschutz, J H; Mostov, K E et al. (2001) Localization of GFP-tagged concentrative nucleoside transporters in a renal polarized epithelial cell line. Am J Physiol Renal Physiol 280:F879-85
Lipschutz, J H (1999) To clone or not to clone--a Jewish perspective. J Med Ethics 25:105-7
Balkovetz, D F; Lipschutz, J H (1999) Hepatocyte growth factor and the kidney: it is not just for the liver. Int Rev Cytol 186:225-60
Lipschutz, J H; Kissil, J L (1998) Expression of beta-catenin and gamma-catenin in epithelial tumor cell lines and characterization of a unique cell line. Cancer Lett 126:33-41
Lipschutz, J H (1998) Molecular development of the kidney: a review of the results of gene disruption studies. Am J Kidney Dis 31:383-97