title: Enhanced expression of complement C5a receptor mRNA in human diseased kidney assessed by in situ hybridization.
abstract: BACKGROUND
  Anaphylatoxin C5a mediates inflammatory responses through interaction with a specific C5a receptor (C5aR), the expression of which is thought to be restricted to peripheral blood leukocytes. Although the presence of C5aR on cultured mesangial cells and tubular epithelial cells has recently been documented, the tissue distribution of C5aR in diseased kidney has not yet been determined.
  
  
  METHODS
  Immunohistochemistry and nonradioactive in situ hybridization for C5aR were performed in 34 tissue samples of kidneys from patients with various renal diseases, including 4 with minimal change nephrotic syndrome (MCNS), 5 with membranous nephropathy (MN), and 25 with mesangial proliferative glomerulonephritis (mesGN; 15 patients with IgA nephropathy, 5 with non-IgA mesGN, and 5 with lupus nephritis). Normal portions of surgically resected kidney served as the control.
  
  
  RESULTS
  In normal kidneys, C5aR protein was detected in tubular epithelial cells, while C5aR mRNA was detected in a few glomerular cells, tubular epithelial cells, and vascular endothelial and smooth muscle cells. In MCNS, the distribution of C5aR protein and mRNA was similar to that in normal kidneys. In MN and mesGN, C5aR protein and mRNA were detected in mesangial cells, glomerular epithelial and endothelial cells, Bowman's capsule cells, tubular cells, infiltrating cells, and vascular endothelial and smooth muscle cells. The glomerular expression of C5aR mRNA and protein correlated positively with the degree of mesangial hypercellularity and mesangial matrix expansion in mesGN. In the tubulointerstitium, interstitial expression of C5aR mRNA correlated positively with the degree of tubular atrophy and interstitial broadening in mesGN. Furthermore, the interstitial expression of C5aR mRNA correlated positively with the level of serum creatinine.
  
  
  CONCLUSIONS
  Our results indicate that renal cells produce C5aR and that activation of C5a/C5aR pathway on renal cells may be involved in tissue injury in mesGN.
authors: Division of Nephrology, Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan. rukonyan@ga2.so-net.ne.jp
authors: K
authors: K
authors: Abe
authors: M
authors: M
authors: Miyazaki
authors: T
authors: T
authors: Koji
authors: A
authors: A
authors: Furusu
authors: T
authors: T
authors: Nakamura-Kurashige
authors: T
authors: T
authors: Nishino
authors: Y
authors: Y
authors: Ozono
authors: T
authors: T
authors: Harada
authors: H
authors: H
authors: Sakai
authors: S
authors: S
authors: Kohno
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D007674:Kidney Diseases / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism*; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000235:genetics* / Q000378:metabolism; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D015703:Antigens, CD; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D003404:Creatinine