ATF3 regulates SPHK1 in cardiomyocyte injury via endoplasmic reticulum stress

AimEndoplasmic reticulum (ER) stress is common in different human pathologies, including cardiac diseases. Sphingosine kinase-1 (SPHK1) represents an important player in cardiac growth and function. Nevertheless, its function in cardiomyocyte ER stress remains vague. This study sought to evaluate the mechanism through which SPHK1 might influence ER stress during myocardial infarction (MI).MethodsMI-related GEO data sets were queried to screen differentially expressed genes. Murine HL-1 cells exposed to oxygen-glucose deprivation (OGD) and mice with MI were induced, followed by gene expression manipulation using short hairpin RNAs and overexpression vectors. The activating transcription factor 3 (ATF3) and SPHK1 expression was examined in cells and tissues. Cell counting kit-8, TUNEL, DHE, HE, and Masson's staining were conducted in vitro and in vivo. The inflammatory factor concentrations in mouse serum were measured using ELISA. Finally, the transcriptional regulation of SPHK1 by ATF3 was validated.ResultsATF3 and SPHK1 were upregulated in vivo and in vitro. ATF3 downregulation reduced the SPHK1 transcription. ATF3 and SPHK1 downregulation increased the viability of OGD-treated HL-1 cells and decreased apoptosis, oxidative stress, and ER stress. ATF3 and SPHK1 downregulation narrowed the infarction area and attenuated myocardial fibrosis in mice, along with reduced inflammation in the serum and ER stress in the myocardium. In contrast, SPHK1 reduced the protective effect of ATF3 downregulation in vitro and in vivo.ConclusionsATF3 downregulation reduced SPHK1 expression to attenuate cardiomyocyte injury in MI. Stimulation of activating transcription factor 3 (ATF3) exerts pro-fibrotic and proinflammatory effect and expedite endoplasmic reticulum (ER) stress in cardiomyocytes via sphingosine kinase 1 (SPHK1). Thus, the inhibition of ATF3 and SPHK1 may have therapeutic potential for MI. Our understanding of ER stress during MI are still rudimentary, and more research is needed to support our conclusion.image

Automated summary

ATF3 downregulation reduces SPHK1 expression and attenuates cardiomyocyte injury in MI. Stimulation of activating transcription factor 3 (ATF3) exerts pro-fibrotic and proinflammatory effect and expedite endoplasmic reticulum (ER) stress in cardiomyocytes via sphingosine kinase 1 (SPHK1). The inhibition of ATF3 and SPHK1 may have therapeutic potential for MI.