title: In situ localization of C3 synthesis in experimental acute renal allograft rejection.
abstract: Recent evidence has implicated complement in renal transplant injury and identified the kidney as a source of complement components. We therefore investigated the local gene expression of complement component C3, pivotal to complement activation pathways and a mediator of inflammatory injury, in a rat renal transplant model. By reverse transcriptase-polymerase chain reaction, the expression of C3 mRNA increased in two phases. The first phase coincided with post-ischemic injury over 2 days post-transplantation and was localized by in situ hybridization to vessels and glomerular mesangial cells in allogeneic and syngeneic (control) kidney transplants. In allografts only, a second phase was found in tubular epithelial cells, glomerular parietal cells, vessel walls and some infiltrating cells, which peaked on day 4 together with rapid influx of leukocytes, tubule cell damage, the induction of interleukin-2 and interferon-gamma mRNA, and the up-regulation of tumor necrosis factor-alpha and interleukin-1beta mRNA in the graft. In vitro studies showed that interleukin-2 and interferon-gamma up-regulate C3 production in renal tubule cells. We conclude that post-ischemic injury led to transient up-regulation of glomerular expression of C3 mRNA. Subsequent cellular rejection was associated with tubulointerstitial/glomerular parietal cell expression of C3 mRNA. This differential expression of local C3, immediately post-transplant or associated with acute rejection, may have implications for putative therapeutic complement inhibition in clinical transplantation.
authors.affiliation: Department of Nephrology and Transplantation, King's College, University of London, Guy's Hospital, London, United Kingdom. julian.pratt@kcl.ac.uk
authors.forename: J R
authors.initials: JR
authors.lastname: Pratt
authors.forename: K
authors.initials: K
authors.lastname: Abe
authors.forename: M
authors.initials: M
authors.lastname: Miyazaki
authors.forename: W
authors.initials: W
authors.lastname: Zhou
authors.forename: S H
authors.initials: SH
authors.lastname: Sacks
mesh_terms: D000208:Acute Disease; D000818:Animals; D002461:Cell Line, Transformed; D003176:Complement C3 / Q000096:biosynthesis* / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D019084:Fluorescent Antibody Technique, Indirect; D006084:Graft Rejection / Q000378:metabolism* / Q000473:pathology; D017403:In Situ Hybridization; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D007375:Interleukin-1 / Q000096:biosynthesis / Q000235:genetics; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D016030:Kidney Transplantation; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014184:Transplantation, Homologous; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics; D015854:Up-Regulation
chemical_list: D003176:Complement C3; D017931:DNA Primers; D007375:Interleukin-1; D007376:Interleukin-2; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma