Testosterone antagonizes paraquat-induced cardiomyocyte senescence via the mIGF-1/SIRT1 signaling pathway.

Xing Yu,Guiping Zhu,Zhijian Wang,Jianyi Zheng,Tengfei Cai

doi:10.1590/1414-431x20209849

Abstract

Testosterone has been demonstrated to antagonize doxorubicin-induced cardiomyocyte senescence. However, whether testosterone prevents the paraquat-induced cardiomyocyte senescence is largely unknown. The detection of SA-β-gal activity was performed using senescence β-gal staining kit and the reactive oxygen species levels were determined by reactive oxygen species assay kit. The plasmids for insulin-like growth factor 1 shRNA (sh-mIGF-1), sirtuin-1 shRNA (sh-SIRT1), scramble shRNA (sh-NC), overexpressing mIGF-1 (mIGF-1), overexpressing SIRT1 (SIRT1), and negative controls (NC) were obtained for this study. The expression of target genes was detected using quantitative real-time PCR, immunolabeling, and western blot. We found that testosterone significantly delayed the paraquat-induced HL-1 cardiomyocyte senescence as evidenced by decreasing senescence-associated β-galactosidase activity and reactive oxygen species generation, which were accompanied by the up-regulated expression of mIGF-1 and SIRT1. RNA interference to reduce mIGF-1 and SIRT1 expression showed that testosterone prevented paraquat-induced HL-1 senescence via the mIGF-1/SIRT1 signaling pathway. Furthermore, myocardial contraction was evaluated by expression of genes of the contractile proteins/enzymes, such as α-myosin heavy chain 6 (MHC6), α-myosin heavy chain 7 (MHC7), α-skeletal actin (ACTA-1), and sarco/endoplasmic reticulum calcium ATPase-2 (SERCA2). Testosterone adjusted the above four gene expressions and the adjustment was blocked by mIGF-1 or SIRT1 inhibition. Our findings suggested that the mIGF-1/SIRT1 signaling pathway mediated the protective function of testosterone against the HL-1 cardiomyocyte senescence by paraquat, which provided new clues for the mechanisms underlying the anti-aging role of testosterone in cardiomyocytes.

Highlights

With the rapid aging of the world’s population, heart failure, of which the incidence increases with age, is calling for attention [1,2]
The results showed that testosterone inhibited PQ-induced HL-1 cell senescence in a concentrationdependent manner, as evidenced by the decreasing ratio of SA-b-gal positive cells as well as reactive oxygen species (ROS) level (Figure 1A and B)
We confirmed that testosterone prevented PQ-induced cardiomyocyte senescence, and further studies indicated that the protection was by regulating gene expression of the contractile proteins/ enzymes via mIGF-1/SIRT1 signaling pathway

Summary

Introduction

With the rapid aging of the world’s population, heart failure, of which the incidence increases with age, is calling for attention [1,2]. The heart undergoes a series of physiological and morphological changes with aging, which is called cardiac aging. The modulation of cardiomyocyte aging is of great significance to prevent the occurrence of heart failure. Plasma testosterone level is inversely correlated with the incidence of multiple age-related diseases in elderly men [5]. Some testosterone replacement therapies have suggested that testosterone is able to improve cognitive ability [6], enhance cardiac function [7], and delay cardiomyocyte senescence [8,9]. Testosterone has multiple functions, the relationship between testosterone’s effect of delaying cardiomyocyte senescence and the mIGF-1/ SIRT1 pathway has not been elucidated

Methods

Results

Conclusion