title: Evidence suggesting a role for cathepsin L in an experimental model of glomerulonephritis.
abstract: We have utilized specific, irreversible inhibitors of cysteine proteinases to examine the role of renal cathepsin B and cathepsin L in the proteinuria which occurs in an experimental model of human glomerular disease. Administration of trans-epoxysuccinyl-L-leucylamido-(3-methyl)butane (Ep475) a specific, irreversible inhibitor of cysteine proteinases, including cathepsins B and L, significantly reduced proteinuria in rats with experimentally induced, neutrophil-independent, anti-GBM antibody disease (controls: 10 +/- 1 mg/24 h, N = 8; anti-GBM antibody disease: 203 +/- 30 mg/24 h, N = 8; anti-GBM antibody disease + Ep475: 112 +/- 13 mg/24 h, mean +/- SEM, N = 6, P less than 0.05). There was a marked reduction in the activity of both cathepsin B and cathepsin L in renal cortices obtained from Ep475-treated rats compared to either saline-treated controls or rats treated with anti-GBM IgG only. Administration of Z-Phe-Tyr(O-t-butyl)CHN2, a specific, irreversible cysteine proteinase inhibitor with a high degree of selectivity toward cathepsin L, also caused a reduction in anti-GBM antibody-induced proteinuria (90 +/- 18 mg/24 h, N = 6, P less than 0.05). This reduction in proteinuria was accompanied by a marked decrease (-84%) in the specific activity of renal cortical cathepsin L in Z-Phe-Tyr(O-t-butyl)CHN2-treated rats. However, cathepsin B activity was unchanged. There was no significant change in the renal anti-GBM antibody uptake, plasma urea nitrogen, or plasma creatinine values in the Z-Phe-Tyr(O-t-butyl)CHN2-treated rats compared to rats treated with anti-GBM IgG only or saline-treated controls. These data document the ability of cysteine proteinase inhibitors to decrease the proteinuria which occurs in a neutrophil-independent model of human anti-GBM antibody disease and suggest an important role for cathepsin L in the pathophysiology of the proteinuria which occurs in this model.
authors.affiliation: Department of Biochemistry, Tulane Medical School, New Orleans, Louisiana 70112.
authors.forename: W H
authors.initials: WH
authors.lastname: Baricos
authors.forename: S L
authors.initials: SL
authors.lastname: Cortez
authors.forename: Q C
authors.initials: QC
authors.lastname: Le
authors.forename: L T
authors.initials: LT
authors.lastname: Wu
authors.forename: E
authors.initials: E
authors.lastname: Shaw
authors.forename: K
authors.initials: K
authors.lastname: Hanada
authors.forename: S V
authors.initials: SV
authors.lastname: Shah
mesh_terms: D000818:Animals; D002401:Cathepsin B / Q000378:metabolism; D004195:Disease Models, Animal; D005921:Glomerulonephritis / Q000201:enzymology* / Q000652:urine; D007074:Immunoglobulin G; D007672:Kidney Cortex / Q000201:enzymology*; D008297:Male; D011507:Proteinuria; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
chemical_list: D007074:Immunoglobulin G; D002401:Cathepsin B