Attenuation of TGF-beta-induced apoptosis in primary cultures of hepatocytes by calpain inhibitors.
Apoptosis induced in primary cultures of rat hepatocytes by transforming growth factor beta 1 (TGF-beta 1) was greatly attenuated by inhibitors (5 microM) of calpain I and calpain II, respectively. Both inhibitors prevented the TGF-beta-elicited increase of nucleosomal DNA fragments and the occurrence of DNA-breaks in the TUNEL reaction. The detrimental effect of TGF-beta on cell viability measured by the WST-1 test was strongly reduced by calpain inhibitors. Calpain II > I inhibitors suppressed spontaneous DNA cleavage in hepatocytes during culture and prevented the appearance of immunocytochemically visible TGF-beta (APAAP staining), which occurs in untreated parenchymal cell cultures. The data show that inactivation of calpains attenuates both the TGF-beta-elicited and the spontaneous apoptosis of cultured hepatocytes; the latter effect is likely due to the suppression of endogenous TGF-beta activation. It is suggested that calpains participate in these processes.
Gressner
A M
AM
Department of Clinical Chemistry, Philipps University, Marburg, Germany. gressner@mailer.uni-marburg.de
Lahme
B
B
Roth
S
S
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002154:Calpain / Q000037:antagonists & inhibitors*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D053938:DNA Fragmentation; D007150:Immunohistochemistry; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology
D015853:Cysteine Proteinase Inhibitors; D016212:Transforming Growth Factor beta; D002154:Calpain