title: Proteinases in renal cell death.
abstract: The role of proteinases in renal proximal tubule (RPT) cellular death was examined using specific inhibitors of proteinases. Rabbit RPT suspensions were incubated with antimycin A for 1 h or tetrafluoroethyl-L-cysteine (TFEC) for 4 h in the absence or presence of the specific cysteine proteinase inhibitor L-trans-epoxysuccinyl-leucylamido (4-guanidino)butane (E-64), the serine proteinase inhibitors N-p-tosyl-L-lysine chloromethyl ketone (TLCK) or 3,4-dichloroisocoumarin (DCS), the serine and cysteine proteinase inhibitors leupeptin or antipain, or the aspartic proteinase inhibitor pepstatin. E-64 and pepstatin decreased lactate dehydrogenase (LDH) release, a marker of cell death, from RPT exposed either to antimycin A or TFEC. TLCK, DCS, leupeptin, or antipain did not decrease antimycin A- or TFEC-induced cell death. Bromohydroquinone- or t-butylhydroperoxide-induced cell death was not decreased by any of the proteinase inhibitors. Loss of lysosomal membrane potential, indicated by neutral red release, occurred prior to the onset of antimycin A-induced cell death. Extensive inhibition of lysosomal cathepsins B and L by E-64 was correlated with cytoprotection. However, E-64 was only protective after some cell death had occurred. These results suggest that lysosomal cysteine and aspartic proteinases, but not serine proteinases, play a role in RPT cell death induced by antimycin A or TFEC. The observation that E-64 was only protective after some cell death had occurred suggests that lysosomal cathepsins are released from dying cells and subsequently attack the remaining viable cells.
authors.affiliation: Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, USA.
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: R G
authors.initials: RG
authors.lastname: Schnellmann
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity; D000968:Antimycin A / Q000633:toxicity; D000976:Antipain / Q000494:pharmacology; D002268:Carboxypeptidases / Q000378:metabolism; D043402:Cathepsin A; D002401:Cathepsin B / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D003374:Coumarins / Q000494:pharmacology; D003545:Cysteine / Q000031:analogs & derivatives / Q000633:toxicity; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D010450:Endopeptidases / Q000502:physiology*; D006845:Hydrocarbons, Fluorinated / Q000633:toxicity; D006873:Hydroquinones / Q000633:toxicity; D049934:Isocoumarins; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D007976:Leupeptins / Q000494:pharmacology; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D010436:Pepstatins / Q000494:pharmacology; D010545:Peroxides / Q000633:toxicity; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000633:toxicity; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D014107:Tosyllysine Chloromethyl Ketone / Q000494:pharmacology; D020122:tert-Butylhydroperoxide; D005466:Fluorocarbons
chemical_list: D000900:Anti-Bacterial Agents; D000968:Antimycin A; D000976:Antipain; D002268:Carboxypeptidases; D043402:Cathepsin A; D002401:Cathepsin B; D003374:Coumarins; D003545:Cysteine; D015853:Cysteine Proteinase Inhibitors; D010450:Endopeptidases; D006845:Hydrocarbons, Fluorinated; D006873:Hydroquinones; D049934:Isocoumarins; D007770:L-Lactate Dehydrogenase; D007930:Leucine; D007976:Leupeptins; D010436:Pepstatins; D010545:Peroxides; D017382:Reactive Oxygen Species; D015842:Serine Proteinase Inhibitors; D014107:Tosyllysine Chloromethyl Ketone; D020122:tert-Butylhydroperoxide; C014195:Streptomyces pepsin inhibitor; C046235:3,4-dichloroisocoumarin; C042377:2-bromohydroquinone; C064116:S-(1,1,2,2-tetrafluoroethyl)cysteine; D005466:Fluorocarbons; C032854:leupeptin; C024974:E 64; C031375:pepstatin