The long term objective of this project is to develop a clear understanding of the process of glomerular monocyte infiltration, which is believed to be an important cause of acute glomerular dysfunction and chronic glomerular sclerosis. This laboratory has shown that the production of monocyte chemoattractant protein-1 (MCP-1), a monocyte specific chemotactic peptide, may be induced in glomerular mesangial cells. It was thus postulated that the glomerular mesangial cell regulates monocyte traffic via the production of MCP-1. This hypothesis will initially be studied using an in vitro model of glomerular injury, created by exposing cultured human mesangial cells to complement components, immune complexes, and lipoproteins, stimuli which have been shown to initiate glomerular injury in vivo. Mesangial MCP-1 expression will be assessed by Northern analysis of mesangial mRNA. MCP-1 secretion into the culture supernatants will be confirmed by immunoadsorption with a specific anti-human MCP-1beta antibody, and functional activity will be measured using a monocyte chemotaxis assay. To understand how such diverse stimuli may activate mesangial MCP-1 synthesis, a common mechanism of action will be sought. Possibilities which will be investigated include: 1) stimulus induction of another mesangial cytokine (e.g. IL-1, PDGF) which ultimately regulates MCP-1 gene expression, and 2) signal transduction through a common second messenger system (e.g. protein kinase C). this model will also be used to investigate mesangial elaboration of chemotaxis inhibitors, providing further evidence for a regulatory role of the mesangial cell in glomerular inflammation. The effect of anti-inflammatory agents in this system will be examined in order to test the susceptibility of MCP-1 expression to pharmacologic interventions. Further studies will be conducted using tissue obtained from human renal biopsy specimens and rodent kidneys. Evidence for the presence of MCP-1 in human glomerular disease will be sought using immunohistochemical analysis of the renal biopsy material; in situ hybridization for MCP-1 mRNA will also be performed to identify the glomerular source of MCP-1 as the mesangial cell. The time course of glomerular MCP-1 mRNA expression following induction of glomerulonephritis will be assessed (by Northern analysis and in situ hybridization) in a rodent model of monocyte-dependent glomerular injury, and correlated to the evolving leukocyte infiltration. Finally, neutralizing antibodies to MCP-1 will be given to rodents during the induction of glomerulonephritis in an attempt to abrogate the monocyte infiltration and the subsequent development of proteinuria. These studies will thus define a central role for the mesangial cell in the regulation of the initial phase of glomerular injury, and document the importance of the novel pro-inflammatory cytokine MCP-1 in recruiting monocytes to the glomerulus. Understanding the mechanisms of mesangial expression of MCP-1 could provide a basis for therapeutically modulating the release of this cytokine, thus preventing or ameliorating the acute glomerular damage and progressive renal insufficiency caused by infiltrating monocytes.

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 #
1R29DK046055-01A1
Application #
3464830
Study Section
Pathology A Study Section (PTHA)
Project Start
1993-08-01
Project End
1998-07-31
Budget Start
1993-08-01
Budget End
1994-07-31
Support Year
1
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Ohio State University
Department
Type
Schools of Medicine
DUNS #
098987217
City
Columbus
State
OH
Country
United States
Zip Code
43210
Rovin, B H; Wilmer, W A; Danne, M et al. (1999) The mitogen-activated protein kinase p38 is necesssary for interleukin 1beta-induced monocyte chemoattractant protein 1 expression by human mesangial cells. Cytokine 11:118-26
Rovin, B H; Phan, L T (1998) Chemotactic factors and renal inflammation. Am J Kidney Dis 31:1065-84
Rovin, B H; Dickerson, J A; Tan, L C et al. (1997) Modulation of IL-1-induced chemokine expression in human mesangial cells through alterations in redox status. Cytokine 9:178-86
Wilmer, W A; Tan, L C; Dickerson, J A et al. (1997) Interleukin-1beta induction of mitogen-activated protein kinases in human mesangial cells. Role of oxidation. J Biol Chem 272:10877-81
Rovin, B H; Doe, N; Tan, L C (1996) Monocyte chemoattractant protein-1 levels in patients with glomerular disease. Am J Kidney Dis 27:640-6
Rovin, B H; Tan, L C; Leonhart, K L et al. (1995) Cyclic adenosine monophosphate and protein kinase C modulate fibronectin production in cultured human mesangial cells. J Lab Clin Med 126:216-23
Rovin, B H; Dickerson, J A; Tan, L C et al. (1995) Activation of nuclear factor-kappa B correlates with MCP-1 expression by human mesangial cells. Kidney Int 48:1263-71
Rovin, B H; Tan, L C (1994) Role of protein kinase pathways in IL-1-induced chemoattractant expression by human mesangial cells. Kidney Int 46:1059-68
Rovin, B H; Rumancik, M; Tan, L et al. (1994) Glomerular expression of monocyte chemoattractant protein-1 in experimental and human glomerulonephritis. Lab Invest 71:536-42