Role of AT1 R-CaN signaling pathway in regulation of Nav1.5 protein ex-pression in hypertrophic ventricular myocytes from neonatal rats / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effect of angiotensin II type 1 receptor (AT1R)-calcineurin (CaN) signa-ling pathway on the expression of sodium current channel Nav 1.5 at mRNA and protein levels in the hypertrophic ventricu-lar myocytes from neonatal rats .METHODS:The ventricular myocytes were isolated from the ventricles of 1-day-old neo-natal Sprague-Dawley rats and were divided into 4 groups according to different drug intervention as control group , pheny-lephrine (PE) group, losartan (Los)+PE group and cyclosporin A (CsA)+PE group.The method of RNA interference mediated by adenovirus carrying short hairpin RNA ( shRNA) was used to knock down the gene which encodes the beta subtype of CaN A subunit (CnAβ) and the cells were divided into 4 groups as Ad-Null group, Ad-Null+PE group, Ad-CnAβshRNA1 group and Ad-CnAβshRNA1+PE group.The mRNA expression of brain natriuretic peptide ( BNP) ,β-my-osin heavy chain (β-MHC) and Nav1.5 was detected by RT-qPCR.The protein levels of CnAβand Nav1.5 in the whole-cell extracts were determined by Western blot analysis .RESULTS:Treatment of the neonatal rat ventricular myocytes with PE for 24 h increased the protein-to-DNA ratio and the mRNA expression of BNP and β-MHC.The size of the cell surface was also increased after PE treatment .Treatment of the cells with PE increased the protein expression of CnAβ, and re-duced the protein expression of Nav 1.5.Both Los and CsA prevented those effects of PE .The mRNA expression of Nav1.5 was reduced by PE , and no significant difference of Nav 1.5 mRNA expression among PE group , Los+PE group and CsA+PE group was observed .Silencing of CnAβin the neonatal rat ventricular myocytes using Ad-CnAβshRNA1 inhibited the ability of PE to increase the mRNA expression of BNP , and diminished the ability of PE to reduce the protein expression of Nav1.5.CONCLUSION:AT1 R-CaN signaling pathway participates in regulating protein expression of Nav 1.5 in the hy-pertrophic ventricular myocytes from neonatal rats .