The long-term goal of this project is to define the role of tyrosine phosphatases in glomerular cell injury. Different growth factors and cytokines are secreted or expressed in the diseased glomerulus and act on glomerular cells including mesangial cells. Signal transduction through tyrosine phosphorylation is a major pathway that mediates the biologic effects of these mediators. The level of total tyrosine phosphate content in the cell depends upon the balanced activities of protein tyrosine kinases and recently recognized protein tyrosine phosphatases (PTPases). Their plan to study molecular mechanisms of tyrosine phosphorylation/dephosphorylation that determine the activation or deactivation state of mesangial cells. They hypothesis is that, along with tyrosine kinases, alteration in the expression and/or activation of mesangial cell specific as well as other more ubiquitous tyrosine phosphatases are responsible for mesangial cell injury during renal, especially glomerular injury. They have employed a polymerase chain reaction based strategy to isolate 1.5 kb of a unique PTPase and are attempting to clone the full-length cDNA. This phosphatase will be expressed in E. coli using a plasmid expression vector under inducible conditions. PTPase will be purified and its activity will be tested and characterized. Antipeptide antibodies and antibody against bacterially produced PTPase will be raised and used to immunoprecipitate and subsequently to assay activity in mesangial cells. To understand the role of cytoplasmic and nuclear factors, they will study regulation of cloned mesangial cell specific PTPase cDNA as well as two other cytoplasmic PTPases, PTP1B and PTP1C. Role of growth factors and cytokines in regulating the activity of these phosphatases will be studied. cDNAs encoding for these PTPases will be transfected into mesangial cells and explored for their ability to activate or deactivate signals necessary for mesangial cell function. Preliminary studies in mesangial cells overexpressing PTP1C demonstrate that this PTPase enhances the proliferative potential of the cells. Regulatory effects of PTPases on signal transducing enzymes such as phospholipase Cg1, phosphatidylinositol 3 kinase, mitogen activated protein kinase and other tyrosine phosphorylated proteins will be explored. They will study a recently identified group of cytoplasmic proteins that undergo tyrosine phosphorylation and function as transcription factors for certain target genes. These proteins are called signal transducers and activators of transcription (STATs). They are tyrosine phosphorylated and show that PDGF stimulates STAT1 and also induces tyrosine phosphorylation of JAK1. Using a gel mobility shift assay, they plan to study activation of other family members of STATs in mesangial cells that overexpress PTPases. The effect of growth factors such as PDGF alone or in combination with selected relevant cytokines will also be studied. Effect of PTPases on activation of STATs and JAKs will be determined in PTPase transfected mesangial cells using immunoprecipitation and immunoblotting.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29DK050190-03
Application #
2713416
Study Section
General Medicine B Study Section (GMB)
Project Start
1996-06-10
Project End
2001-05-31
Budget Start
1998-06-01
Budget End
1999-05-31
Support Year
3
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Texas Health Science Center San Antonio
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Lee, Hak Joo; Lee, Doug Yoon; Mariappan, Meenalakshmi M et al. (2017) Hydrogen sulfide inhibits high glucose-induced NADPH oxidase 4 expression and matrix increase by recruiting inducible nitric oxide synthase in kidney proximal tubular epithelial cells. J Biol Chem 292:5665-5675
Lee, Hak Joo; Feliers, Denis; Mariappan, Meenalakshmi M et al. (2015) Tadalafil Integrates Nitric Oxide-Hydrogen Sulfide Signaling to Inhibit High Glucose-induced Matrix Protein Synthesis in Podocytes. J Biol Chem 290:12014-26
Mariappan, Meenalakshmi M; Prasad, Sanjay; D'Silva, Kristin et al. (2014) Activation of glycogen synthase kinase 3? ameliorates diabetes-induced kidney injury. J Biol Chem 289:35363-75
Lee, Hak Joo; Mariappan, Meenalakshmi M; Feliers, Denis et al. (2012) Hydrogen sulfide inhibits high glucose-induced matrix protein synthesis by activating AMP-activated protein kinase in renal epithelial cells. J Biol Chem 287:4451-61
Sataranatarajan, Kavithalakshmi; Feliers, Denis; Mariappan, Meenalakshmi M et al. (2012) Molecular events in matrix protein metabolism in the aging kidney. Aging Cell 11:1065-73
Mariappan, Meenalakshmi M; D'Silva, Kristin; Lee, Myung Ja et al. (2011) Ribosomal biogenesis induction by high glucose requires activation of upstream binding factor in kidney glomerular epithelial cells. Am J Physiol Renal Physiol 300:F219-30
Lee, Hsiang-Ying; Johnson, Kirby D; Boyer, Meghan E et al. (2011) Relocalizing genetic loci into specific subnuclear neighborhoods. J Biol Chem 286:18834-44
Lee, Myung-Ja; Feliers, Denis; Sataranatarajan, Kavithalakshmi et al. (2010) Resveratrol ameliorates high glucose-induced protein synthesis in glomerular epithelial cells. Cell Signal 22:65-70
Block, Karen; Gorin, Yves; New, David D et al. (2010) The NADPH oxidase subunit p22phox inhibits the function of the tumor suppressor protein tuberin. Am J Pathol 176:2447-55
Kasinath, Balakuntalam S; Feliers, Denis; Sataranatarajan, Kavithalakshmi et al. (2009) Regulation of mRNA translation in renal physiology and disease. Am J Physiol Renal Physiol 297:F1153-65

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