Exploring key regulators involved in cardiac ischemic preconditioning through proteomic analysis in ischemia reperfusion mice models

Background Reperfusion therapy improved acute coronary syndrome (ACS) patients’ prognosis. However, the ischemia-reperfusion (IR) injury remains unsolved. During clinical practice, patients with recurrent angina manifested better outcomes after ACS, suggesting brief periods of sublethal ischemia separated by periods of short bursts of reperfusion delivered before the ischemic insult, known as ischemic preconditioning (IPC) could provide the cardio-myocardium with a means of protecting against ACS. However, the exact physiological mechanism remains controversial. Based on proteomic analysis, this study explored the role of mitochondrial metabolism in IPC and potential targets of IPC. Methods IR and IPC mice models were established as protocol, and myocardium tissue was acquired from animal models as samples. Mass spectrometry analysis was employed to acquire the protein expression profile. Comprehensive proteomic analysis was performed for differentially expressed protein acquisition, functional enrichment, hub gene identification, etc. GSE45818 was obtained from NCBI GEO for external validation. Results After the left anterior descending artery ligation, the myocardial blush was diminished and restored after untied. The following hematoxylin-eosin staining of cardiac slices demonstrating IPC and IR mice models were well established. After that, the rest of the cardiac samples were further proceeded through mass spectrometry analysis, and 3034 effective proteins were identified by mass spectrometry analysis. Among them, 145 proteins were significantly expressed between IPC and IR groups, and their corresponding genes’ function was enriched in mitochondrial translation and gene expression, ribosome component, etc. Differentially expressed genes (DEG) intersecting with mitochondrial genes were 19 mitochondria-related DEGs. Based on that, nine hub genes were obtained via PPI network analysis ( Cox4i1, Cox5a, Cox7b, Ndufa2, Ndufa11, Ndufs2, Ndufs3, Ndufv1 , and Uqcr11 ). Combined with protein expression data, 3 hub genes ( Cox4i1, Cox7b , and Ndufa2 ) were differentially expressed between IR and IPC groups. The Cox4i1 showed adequate discrimination ability in external validation. Conclusions Our findings suggest that IPC may exert therapeutic effects through up-regulating Cox4i1 expression in alleviating IR injury, and COX4 isoform changing could be a promising regulatory target of IR.