Overexpression of TRPC3 increases apoptosis but not necrosis in response to ischemia-reperfusion in adult mouse cardiomyocytes.
Am J Physiol Cell Physiol
; 294(3): C833-41, 2008 Mar.
Article
em En
| MEDLINE
| ID: mdl-18184877
ABSTRACT
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 microM) significantly improved cellular viability (54 +/- 4%) and decreased apoptosis (15 +/- 4%); in contrast, the L-type Ca2+ channel inhibitor verapamil (10 microM) had no effect. Calpain-mediated cleavage of alpha-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 microM) attenuated the increase in both alpha-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-alpha-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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Traumatismo por Reperfusão Miocárdica
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Apoptose
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Sinalização do Cálcio
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Miócitos Cardíacos
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Canais de Cátion TRPC
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol Cell Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos