Lin28a protects against hypoxia/reoxygenation induced cardiomyocytes apoptosis by alleviating mitochondrial dysfunction under high glucose/high fat conditions.

Mingming Zhang,Dongdong Sun,Shuhong Sun,Chen Wang,Jianqiang Hu,Haichang Wang,Wenjun Yu,Xiaolin Niu,Yuan Yuan,Jiaxing Wang

doi:10.1371/journal.pone.0110580

Mingming Zhang, Dongdong Sun + Show 8 more

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https://doi.org/10.1371/journal.pone.0110580

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Journal: PloS one	Publication Date: Oct 14, 2014
Citations: 21	License type: CC BY 4.0

Affiliation: Air Force Medical University, Xijing Hospital

Abstract

AimThe aim of the present study was to investigate the role of Lin28a in protecting against hypoxia/reoxygenation (H/R)-induced cardiomyocytes apoptosis under high glucose/high fat (HG/HF) conditions.MethodsPrimary cardiomyocytes which were isolated from neonatal mouse were randomized to be treated with lentivirus carrying Lin28a siRNA, Lin28acDNA 72 h before H/R (9 h/2 h). Cardiomyocytes biomarkers release (LDH and CK), cardiomyocytes apoptosis, mitochondria biogenesis and morphology, intracellular reactive oxygen species (ROS) production, ATP content and inflammatory cytokines levels after H/R injury in high glucose/high fat conditions were compared between groups. The target proteins of Lin28a were examined by western blot analysis.ResultsOur results revealed that Lin28a cDNA transfection (overexpression) significantly inhibited cardiomyocyte apoptotic index, improved mitochondria biogenesis, increased ATP production and reduced ROS production as compared with the H/R group in HG/HF conditions. Lin28a siRNA transfection (knockdown) rendered the cardiomyocytes more susceptible to H/R injury as evidenced by increased apoptotic index, impaired mitochondrial biogenesis, decreased ATP production and increased ROS level. Interestingly, these effects of Lin28a were blocked by pretreatment with the PI3K inhibitor wortmannin. Lin28a overexpression increased, while Lin28a knockdown inhibited IGF1R, Nrf-1, Tfam, p-IRS-1, p-Akt, p-mTOR, p-p70s6k, p-AMPK expression levels after H/R injury in HG/HF conditions. Moreover, pretreatment with wortmannin abolished the effects of Lin28a on the expression levels of p-AKT, p-mTOR, p-p70s6k, p-AMPK.ConclusionsThe present results suggest that Lin28a inhibits cardiomyocytes apoptosis by enhancing mitochondrial biogenesis and function under high glucose/high fat conditions. The mechanism responsible for the effects of Lin28a is associated with the PI3K/Akt dependent pathway.

Highlights

The escalating epidemic of diabetes (DM) represents one of the most pressing and costly biomedical challenges confronting modern society [1]
We investigated whether the effects of Lin28a in protecting against cardiomyocyte H/R injury in high glucose/high fat (HG/HF) condition was related to insulinPI3K-mTOR pathway
The results showed that Lin28a overexpression increased, while Lin28a knockdown decreased IGF1R, pIRS-1, p-Akt, p-mTOR and p-p70s6k expression levels after cardiomyocytes H/R injury in HG/HF incubation

Summary

Introduction

The escalating epidemic of diabetes (DM) represents one of the most pressing and costly biomedical challenges confronting modern society [1]. This growth in diabetes prevalence is occurring in both developing and developed countries. The World Health Organization (WHO) predicts the number of diabetic patients will increase to at least 366 million by the year 2030 [2]. Cardiovascular diseases (CVD) are the most prevalent cause of mortality and morbidity among diabetic patients [3,4,5]. The efficacy of glycemic control and other cardiovascular risk factors in diabetic patients have been demonstrated, the majority of diabetic patients never achieve the goals established by guidelines issued by diabetes societies [6,7,8]. Mitochondria are involved in many other cellular processes including cell death, and are regarded as a major target of MI/R injury [9,10]

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