Thymosin beta 4 protects cardiomyocytes from oxidative stress by targeting anti-oxidative enzymes and anti-apoptotic genes.

ABSTRACT:

Background

Thymosin beta-4 (T?4) is a ubiquitous protein with many properties relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory mediators. The mechanism by which T?4 modulates cardiac protection under oxidative stress is not known. The purpose of this study is to dissect the cardioprotective mechanism of T?4 on H(2)O(2) induced cardiac damage.

Methods

Rat neonatal cardiomyocytes with or without T?4 pretreatment were exposed to H(2)O(2) and expression of antioxidant, apoptotic, and anti-inflammatory genes was evaluated by quantitative real-time PCR and western blotting. ROS levels were estimated by DCF-DA using fluorescent microscopy and fluorimetry. Selected antioxidant, anti-inflammatory and antiapoptotic genes were silenced by siRNA transfections in neonatal cardiomyocytes and effect of T?4 on H(2)O(2)-induced cardiac damage was evaluated.

Results

Pre-treatment of T?4 resulted in reduction of the intracellular ROS levels induced by H(2)O(2) in cardiomyocytes. T?4 pretreatment also resulted in an increase in the expression of antiapoptotic proteins and reduction of Bax/BCl(2) ratio in the cardiomyocytes. Pretreatment with T?4 resulted in stimulating the expression of antioxidant enzymes copper/zinc SOD and catalase in cardiomyocytes at both transcription and translation levels. T?4 treatment resulted in the increased expression of anti-apoptotic and anti-inflammatory genes. Silencing of Cu/Zn SOD and catalase gene resulted in apoptotic cell death in the cardiomyocytes which was prevented by treatment with T?4.

Conclusion

This is the first report that demonstrates the effect of T?4 on cardiomyocytes and its capability to selectively upregulate anti-oxidative enzymes, anti-inflammatory genes, and antiapoptotic enzymes in the neonatal cardiomyocytes thus preventing cell death thereby protecting the myocardium. T?4 treatment resulted in decreased oxidative stress and inflammation in the myocardium under oxidative stress.

SUBMITTER: Wei C 

PROVIDER: S-EPMC3411836 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature