Accumulating evidence implicates growth factors that bind to receptors with protein tyrosine kinase (PTK) activity in the pathogenesis of chronic renal failure. Recent evidence from this laboratory and others suggests that vasoactive peptides binding to G protein-coupled receptors constitute a novel group of growth factors. This class of growth factors (i.e., endothelin, angiotensin II) has also been implicated in diverse vascular disorders and in renal failure. But in contrast to growth factors that bind to receptor PTK, relatively little is known about the signals by which activated G protein-coupled receptors stimulate cell growth. The long-term goal of this project is to understand the signal transduction pathways mediating transcription and mitogenesis by growth factors that bind to G protein-coupled receptors. The focus is on endothelin (ET) peptides and cytosolic and nuclear effectors that lead to mitogenesis in glomerular mesangial cells. First, we will use pharmacological and molecular biological approaches to characterize the ET receptor subtype mediating mitogenic signaling. We will also test the hypothesis that protein kinase C (PKC) and PTK activity are necessary for stimulating the serum response cis-element and mitogenesis by ET-1. We have chosen to study the serum response element (SRE) because it is a dominant cis- element in the promoters of many immediate-early genes, whose expression are required for the G-o-G-l transition. PKC inhibition and depletion will be used to test whether PKC mediates the increase in SRE activity and mitogenesis by ET-1. SRE activity will be measured in transient transactivation assays with reporter constructs linked to the bacterial chloramphenicol acetyltransferase gene. We will also test the hypothesis that ET-1 stimulates a PTK activity, perhaps the nonreceptor PTK pp60c- src, and that this PTK activity is required for SRE activation and mitogenesis. The demonstration that ET-1 increases pp6Oc-src activity suggests that cross-talk between G protein-coupled receptors and non- receptor PTK contribute to mitogenic signaling. Activation of pp60c-src by ET-1 considerably enlarges on potential candidates for downstream effectors of ET receptors; potential effectors linked to pp60c-src include phosphatidyl inositol 3-kinase, ras GAP, and phospholipase C-gamma. The experiments outlined in this proposal will enable us to construct a molecular model of mitogenic signals evoked by ET-1. Predictions derived from this model might be useful in designing novel pharmacological interventions aimed at preventing the growth factor actions of ET-1. Because ET-1 has been implicated the vascular response to injury and in renal failure, the ability to block the mitogenic actions of ET might be relevant in clinical settings.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK046939-02
Application #
2146239
Study Section
Pathology A Study Section (PTHA)
Project Start
1993-08-01
Project End
1998-07-31
Budget Start
1994-08-01
Budget End
1995-07-31
Support Year
2
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Case Western Reserve University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Mishra, Rangnath; Wang, Yuan; Simonson, Michael S (2005) Cell cycle signaling by endothelin-1 requires Src nonreceptor protein tyrosine kinase. Mol Pharmacol 67:2049-56
Wang, Yuan; Mishra, Rangnath; Simonson, Michael S (2003) Ca2+/calmodulin-dependent protein kinase II stimulates c-fos transcription and DNA synthesis by a Src-based mechanism in glomerular mesangial cells. J Am Soc Nephrol 14:28-36
Mishra, Rangnath; Leahy, Patrick; Simonson, Michael S (2003) Gene expression profile of endothelin-1-induced growth in glomerular mesangial cells. Am J Physiol Cell Physiol 285:C1109-15
Mishra, Rangnath; Leahy, Patrick; Simonson, Michael S (2002) Gene expression profiling reveals role for EGF-family ligands in mesangial cell proliferation. Am J Physiol Renal Physiol 283:F1151-9
Simonson, Michael S; Robinson, Ann V; Schulak, James A et al. (2002) Inhibition of endothelin-1 improves survival and vasculopathy in rat cardiac transplants treated with cyclosporine. Transplantation 73:1054-9
Chareandee, C; Herman, W H; Hricik, D E et al. (2000) Elevated endothelin-1 in tubular epithelium is associated with renal allograft rejection. Am J Kidney Dis 36:541-9
Simonson, M S; Herman, W H; Robinson, A et al. (1999) Inhibition of endothelin-converting enzyme attenuates transplant vasculopathy and rejection in rat cardiac allografts. Transplantation 67:1542-7
Simonson, M S; Hricik, D E (1999) Nitric oxide upregulates HLA-DR in human vascular endothelial cells. Transplant Proc 31:737-8
Simonson, M S; Herman, W H; Knauss, T C et al. (1999) Macrophages--but not T-cell--derived cytokines stimulate endothelin-1 secretion by endothelial cells. Transplant Proc 31:806-7
Herman, W H; Holcomb, J M; Hricik, D E et al. (1999) Interleukin-1 beta induces endothelin-1 gene by multiple mechanisms. Transplant Proc 31:1412-3

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