HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 294/3/C833    most recent 00313.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Shan, D. Articles by Chatham, J. C. Search for Related Content PubMed PubMed Citation Articles by Shan, D. Articles by Chatham, J. C.

GROWTH, DIFFERENTIATION, AND APOPTOSIS

Overexpression of TRPC3 increases apoptosis but not necrosis in response to ischemia-reperfusion in adult mouse cardiomyocytes

¹Division of Cardiovascular Disease, Department of Medicine and ²Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama

Submitted 20 July 2007 ; accepted in final form 7 January 2008

An increase in cytosolic Ca²⁺ via a capacitative calcium entry (CCE)-mediated pathway, attributed to members of the transient receptor potential (TRP) superfamily, TRPC1 and TRPC3, has been reported to play an important role in regulating cardiomyocyte hypertrophy. Increased cytosolic Ca²⁺ also plays a critical role in mediating cell death in response to ischemia-reperfusion (I/R). Therefore, we tested the hypothesis that overexpression of TRPC3 in cardiomyocytes will increase sensitivity to I/R injury. Adult cardiomyocytes isolated from wild-type (WT) mice and from mice overexpressing TRPC3 in the heart were subjected to 90 min of ischemia and 3 h of reperfusion. After I/R, viability was 51 ± 1% in WT mice and 42 ± 5% in transgenic mice (P < 0.05). Apoptosis assessed by annexin V was significantly increased in the TRPC3 group compared with WT (32 ± 1% vs. 21 ± 3%; P < 0.05); however, there was no significant difference in necrosis between groups. Treatment of TRPC3 cells with the CCE inhibitor SKF-96365 (0.5 µM) significantly improved cellular viability (54 ± 4%) and decreased apoptosis (15 ± 4%); in contrast, the L-type Ca²⁺ channel inhibitor verapamil (10 µM) had no effect. Calpain-mediated cleavage of -fodrin was increased approximately threefold in the transgenic group following I/R compared with WT (P < 0.05); this was significantly attenuated by SKF-96365. The calpain inhibitor PD-150606 (25 µM) attenuated the increase in both -fodrin cleavage and apoptosis in the TPRC3 group. Increased TRPC3 expression also increased sensitivity to Ca²⁺ overload stress, but it did not affect the response to TNF--induced apoptosis. These results suggest that CCE mediated via TRPC may play a role in cardiomyocyte apoptosis following I/R due, at least in part, to increased calpain activation.

capacitative calcium entry; calpain; tumor necrosis factor-; transient receptor potential