The inhibitory effect of prostaglandin E-1 on oxidative stress-induced hepatocyte injury evaluated by calpain-mu activation

Citation
S. Kishimoto et al., The inhibitory effect of prostaglandin E-1 on oxidative stress-induced hepatocyte injury evaluated by calpain-mu activation, TRANSPLANT, 69(11), 2000, pp. 2314-2319
Citations number
50
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Medical Research Diagnosis & Treatment
Journal title
TRANSPLANTATION
ISSN journal
0041-1337 → ACNP
Volume
69
Issue
11
Year of publication
2000
Pages
2314 - 2319
Database
ISI
SICI code
0041-1337(20000615)69:11<2314:TIEOPE>2.0.ZU;2-B
Abstract
Background. Prostaglandin E-1 (PGE(1)) is known to inhibit ischemia-reperfu sion injury of the liver. The calcium dependent neutral proteinase, calpain -mu, is involved in oxidative stress-induced hepatocyte injury. We investig ated the mechanisms of cytoprotection by PGE(1), focusing on the elevation of intracellular calcium ([Ca2+](i)), activation of calpain-mu, and calpain -mu-mediated activation of protein kinase C-alpha (PKC-alpha), Methods. Cultured hepatocytes were treated with various amounts of PGE(1) ( 0, 0.1, 1.0, 10, and 100 ng/ml) for 30 min and subsequently with 0.5 mM ter t-butyl hydroperoxide (TBHP), Cell injury was evaluated by the release of l actate dehydrogenase, Plasma membrane bleb formation was examined by phase contrast microscopy, Activation of calpain-mu and limited degradation of PK C-alpha was evaluated by Western blotting using antibodies that specificall y recognize the aminoterminal regions of calpain-mu and PKC-alpha, [Ca2+](i ) was measured by confocal microscopy using Fluo-3AM. Results, LDH release from cells treated with 10 ng/ml PGE, was significantl y lower than from untreated cells (135+/-12 vs. 258+/-18 IU/L, respectively ; P<0.05), Morphologically, many blebs were observed in untreated cells, bu t very few were seen in those treated with 10 ng/ml PGE(1). Western blottin g revealed that the amount of activated calpain-mu and [Ca2+](i) increased up to 1,300 nM at 35 min after the addition of TBHP (0.5 mmol/L) in control experiments (without PGE(1)). PGE(1) (10 ng/ml) delayed the rise in [Ca2+] (i) for about 30 min, but did not suppress it completely. PKC-alpha decreas ed in experiments using PGE(1) (10 ng/ml), Conclusion, PGE(1) exerts its cytoprotective effect in TBHP-induced hepatoc yte injury partly by inhibiting Ca2+-calpain-mu-mediated mechanisms.