Abstract
BackgroundGestational diabetes mellitus is a risk factor for congenital heart defects. The article aimed to investigate the expression and roles of MST1, YAP1, Last1/2 and Survivin in modulating HG-induced cardiomyocyte apoptosis and maternal diabetes-induced heart abnormality.MethodsDiabetes mellitus was induced in rats using streptozotocin. The protein expression and phosphorylation analysis in fetal heart tissue was assessed by western blot and immunohistochemical staining. Hoechst 33342 staining assay was performed to explore H9C2 apoptosis. The gene and protein expression in H9C2 cells was assessed by quantitative PCR and western blot. Knockdown of gene expression was assessed by RNA interference.ResultsOur results revealed that increased MST1 protein levels in the heart tissues of the offspring of diabetic rats in vivo and in H9C2 cardiomyocytes under HG treatment in vitro, respectively. Knockdown and overexpression experiments showed that MST1 played a key role in mediating HG-induced apoptosis in cardiomyocytes. Downregulation of YAP1 was associated with HG-induced, MST1-mediated cardiomyocyte apoptosis. Further study showed that MST1 downregulated the protein level of YAP1 through mediation of YAP1 phosphorylation on Ser127 and Ser397; this process also required LATS1/2 participation. MST1 overexpression increased the phosphorylation levels of LATS1/2, which were also shown to be increased in the heart tissues of diabetic offspring. We also found that YAP1 mediated the expression of Survivin during HG-induced apoptosis, and the Survivin-inhibitor YM155 partially inhibited the role of YAP1 in suppressing apoptosis induced by HG in cardiomyocytes.ConclusionThese findings reveal a regulatory mechanism of MST1/YAP1/Survivin signaling in modulating cardiomyocyte apoptosis in vitro and maternal diabetes-induced congenital heart defects in vivo.
Highlights
Congenital heart disease (CHD) is a common defect that clinically manifests as anomalies in the heart and great vessels (Miller et al 2016)
By analyzing the expression pattern of Mammalian sterile 20-like kinase 1 (MST1), Yes-associated protein 1 (YAP1) and Survivin after exposure to high glucose (HG), we aimed to identify the molecular mechanism of these proteins and the Hippo pathway in modulating HG-induced cardiomyocyte apoptosis and maternal diabetes-induced CHD
Upregulation of MST1 in cardiomyocytes of diabetic offspring in vivo and in vitro IHC revealed an increase in MST1 protein level in the heart tissues of diabetes-exposed embryos (Fig. 1a), that was confirmed by western blotting (Fig. 1b and Additional file 1: Fig. S1A)
Summary
Congenital heart disease (CHD) is a common defect that clinically manifests as anomalies in the heart and great vessels (Miller et al 2016). Postnatal studies have revealed that the mothers of many infants with abnormalities involving CHD have diabetes (Priest et al 2015; Correa et al 2008). The molecular basis of CHD pathogenesis in pregestational diabetes remains largely uncharacterized. Previous studies described diabetes-induced congenital malformations that occur during heart development, with some reporting increased numbers of apoptotic myocardial cells that participate in gestational diabetes mellitus-induced heart abnormalities (Moazzen et al 2014; Bohuslavova et al 2013; Gutierrez et al 2009). The molecular mechanisms and factors responsible for the high incidence of CHD in pregestational diabetes require further elucidation. Gestational diabetes mellitus is a risk factor for congenital heart defects. The article aimed to investigate the expression and roles of MST1, YAP1, Last1/2 and Survivin in modulating HG-induced cardiomyocyte apoptosis and maternal diabetes-induced heart abnormality
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