Differential Gene Expression Patterns in Chicken Cardiomyocytes during Hydrogen Peroxide-Induced Apoptosis.

Youwen Li,Dingzong Guo,Rodrigo Franco,Chunyun Wan,Jinmei Xiang

doi:10.1371/journal.pone.0147950

Abstract

Hydrogen peroxide (H2O2) is both an exogenous and endogenous cytotoxic agent that can reliably induce apoptosis in numerous cell types for studies on apoptosis signaling pathways. However, little is known of these apoptotic processes in myocardial cells of chicken, a species prone to progressive heart failure. Sequencing of mRNA transcripts (RNA-Seq) allows for the identification of differentially expressed genes under various physiological and pathological conditions to elucidate the molecular pathways involved, including cellular responses to exogenous and endogenous toxins. We used RNA-seq to examine genes differentially expressed during H2O2-induced apoptosis in primary cultures of embryonic chicken cardiomyocytes. Following control or H2O2 treatment, RNA was extracted and sequencing performed to identify novel transcripts up- or downregulated in the H2O2 treatment group and construct protein−protein interaction networks. Of the 19,268 known and 2,160 novel transcripts identified in both control and H2O2 treatment groups, 4,650 showed significant differential expression. Among them, 55.63% were upregulated and 44.37% downregulated. Initiation of apoptosis by H2O2 was associated with upregulation of caspase-8, caspase-9, and caspase-3, and downregulation of anti-apoptotic genes API5 and TRIA1. Many other differentially expressed genes were associated with metabolic pathways (including ‘Fatty acid metabolism’, ‘Alanine, aspartate, and glutamate metabolism’, and ‘Biosynthesis of unsaturated fatty acids’) and cell signaling pathways (including ‘PPAR signaling pathway’, ‘Adipocytokine signaling pathway’, ‘TGF-beta signaling pathway’, ‘MAPK signaling pathway’, and ‘p53 signaling pathway’). In chicken cardiomyocytes, H2O2 alters the expression of numerous genes linked to cell signaling and metabolism as well as genes directly associated with apoptosis. In particular, H2O2 also affects the biosynthesis and processing of proteins and unsaturated fatty acids. These results highlight the value of RNA-seq for revealing unexpected molecular contributors to oxidative stress responses, thereby identifying novel potential therapeutic targets.

Highlights

Cell apoptosis was first described in 1972 [1] and soon thereafter implicated in myocardial cell death associated with heart failure [2]
Many strains of rapidly growing chickens are susceptible to cardiomyocyte apoptosis and progressive of rapidly growing chickens are susceptible to heart disease, including heart failures to see if etnclude context-aheart failure as a result of diseases such as broiler pulmonary hypertension syndrome [6]
Our results showed that apoptosis initiation predominantly relies on caspase-8 and caspase-9 upregulation, leading to caspase-3 activation, so H2O2-induced apoptosis in chicken cardiomyocytes depends on the canonical apoptosis pathway

Summary

Introduction

Cell apoptosis was first described in 1972 [1] and soon thereafter implicated in myocardial cell death associated with heart failure [2]. Hydrogen peroxide (H2O2) has well known cytotoxic effects. It is a common exogenous toxin, but is produced endogenously (e.g., by superoxide dismutase), which can lead to cellular apoptosis. Myocardial cells are terminally differentiated; if these cells undergo apoptosis, they are not regenerated, leading to a progressive reduction in overall heart function and possible heart failure [2]. Describing the mechanisms of apoptosis in cardiomyocytes is critical for understanding the pathogenesis of heart failure and for developing ameliorative treatments. Cardiomyocyte apoptosis and heart failure are common in chickens. Many strains of rapidly growing chickens are susceptible to cardiomyocyte apoptosis and progressive of rapidly growing chickens are susceptible to heart disease, including heart failures to see if etnclude context-aheart failure as a result of diseases such as broiler pulmonary hypertension syndrome [6]

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