title: Existence of a regulatory loop between MCP-1 and TGF-beta in glomerular immune injury.
abstract: Glomerular upregulation of monocyte chemotactic protein-1 (MCP-1), followed by an influx of monocytes resulting eventually in extracellular matrix deposition is a common sequel of many types of glomerulonephritis. However, it is not entirely clear how early expression of MCP-1 is linked to the later development of glomerulosclerosis. Because transforming growth factor-beta (TGF-beta) is a key regulator of extracellular matrix proteins, we hypothesized that there might be a regulatory loop between early glomerular MCP-1 induction and subsequent TGF-beta expression. To avoid interference with other cytokines that may be released from infiltrating monocytes, isolated rat kidneys were perfused with a polyclonal anti-thymocyte-1 antiserum (ATS) and rat serum (RS) as a complement source to induce glomerular injury. Renal TGF-beta protein and mRNA expressions were strongly stimulated after perfusion with ATS-RS. This effect was attenuated by coperfusion with a neutralizing anti-MCP-1 but was partly mimicked by perfusion with recombinant MCP-1 protein. On the other hand, renal MCP-1 expression and production were stimulated by administration of ATS-RS. Additional perfusion with an anti-TGF-beta antibody further aggravated this increase, whereas application of recombinant TGF-beta protein reduced MCP-1 formation. Our data demonstrate an intrinsic regulatory loop in which increased MCP-1 levels stimulate TGF-beta formation in resident glomerular cells in the absence of infiltrating immune competent cells.
authors.affiliation: Division of Nephrology, Department of Medicine, University of Hamburg, 20246 Hamburg, Germany. Wolf@uke.uni-hamburg.de
authors.forename: Gunter
authors.initials: G
authors.lastname: Wolf
authors.forename: Thomas
authors.initials: T
authors.lastname: Jocks
authors.forename: Gunther
authors.initials: G
authors.lastname: Zahner
authors.forename: Ulf
authors.initials: U
authors.lastname: Panzer
authors.forename: Rolf A K
authors.initials: RA
authors.lastname: Stahl
mesh_terms: D000818:Animals; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000276:immunology / Q000378:metabolism; D015870:Gene Expression / Q000502:physiology; D005921:Glomerulonephritis / Q000276:immunology* / Q000378:metabolism*; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D054390:Receptors, CCR2; D019707:Receptors, Chemokine / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D014556:Urine
chemical_list: C515336:Ccr2 protein, rat; D018932:Chemokine CCL2; D012333:RNA, Messenger; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D016212:Transforming Growth Factor beta