Abstract
The goal of the present study was to determine the role of calpain in changes in plasma membrane permeability and cytoskeleton-associated paxillin, vinculin, talin, and α-actinin levels during acute renal cell death. The mitochondrial inhibitor antimycin A or hypoxia produced graded plasma membrane permeability in renal proximal tubules (RPTs), first allowing propidium iodide (PI, molecular mass 668 Da) influx and then lactate dehydrogenase (LDH, molecular mass 130 kDa) release. Cytoskeleton-associated paxillin levels decreased concomitantly with PI influx and before LDH release, whereas cytoskeleton-associated talin and vinculin levels decreased concomitantly with LDH release. Cytoskeleton-associated α-actinin levels did not change during antimycin A exposure or hypoxia. Purified μ-calpain cleaved paxillin, talin, vinculin, but not α-actinin. The dissimilar calpain inhibitors 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606) or chloroacetic acidN′-[6,7-dichloro-4-phenyl)-3-oxo-3,4-dihydroquinoxalin-2-yl] hydrazide (SJA7029) preserved cytoskeleton-associated paxillin, talin, and vinculin levels and prevented PI influx and LDH release in antimycin A-exposed or hypoxic RPTs. These results suggest that calpain mediates increased plasma membrane permeability and hydrolysis of cytoskeleton-associated paxillin, vinculin, and talin during renal cell death.
Footnotes
-
This work was supported by National Institute of Environmental Heath Grant NIH ES-09129 (to R.G.S.) and predoctoral fellowship (to X.L.) from the American Heart Association, Heartland Affiliate. Portions of this work were presented at the 41st Annual Meeting of the Society of Toxicology in Nashville, TN, March 2001.
-
DOI: 10.1124/jpet.102.043406
- Abbreviations:
- RPT
- renal proximal tubule
- PI
- propidium iodide
- LDH
- lactate dehydrogenase
- MDCK
- Madin-Darby canine kidney
- PD150606
- 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid
- SJA7019
- chloroacetic acidN′-[6,7-dichloro-4-phenyl)-3-oxo-3,4-dihydroquinoxalin-2-yl]hydrazide
- DMSO
- dimethyl sulfoxide
- DAPI
- 4′,6-diamidino-2-phenylindole
- Received August 20, 2002.
- Accepted September 11, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|