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This study aimed to investigate whether exosomes secreted by mouse GATA-4-expressing bone marrow mesenchymal stem cells (BMSCs) could induce BMSC differentiation into myocyte precursors, decrease cardiomyocyte apoptosis, and improve cardiac function following myocardial infarction (MI). BMSCs were transduced with a lentivirus carrying a doxycycline (DOX)-inducible GATA-4 or control lentivirus, and secreted exosomes from these BMSCs were collected and co-cultured with BMSCs or cardiomyocytes under hypoxic and serum free conditions. Furthermore, exosomes were injected into mice 48 h after MI. Cardiac function was evaluated by echocardiography at 48, 72, and 96 h after exosome treatment. Quantitative PCR showed that co-culture of BMSCs with GATA-4-BMSC exosomes increased cardiomyocyte-related marker expression. Co-culture of GATA-4-BMSC exosomes with cardiomyocytes in anoxic conditions decreased apoptosis as detected by flow cytometry. Injection of GATA-4-BMSC exosomes in mice 48 h after MI increased cardiac function over the next 96 h; increased cardiac blood vessel density and number of c-kit-positive cells and decreased apoptotic cardiomyocyte cells were also observed. Differential expression of candidate differentiation- and apoptosis-related miRNAs and proteins that may mediate these effects was also identified. Exosomes isolated from GATA-4-expressing BMSCs induce differentiation of BMSCs into cardiomyocyte-like cells, decrease anoxia-induced cardiomyocyte apoptosis, and improve myocardial function after infarction.

BackgroundEndothelial-to-mesenchymal transition (EndMT) plays significant roles in atherosclerosis, but the regulatory mechanisms involving lncRNAs remain to be elucidated. Here we sort to identify the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in ox-LDL-induced EndMT.MethodsThe atherosclerosis model was established by feeding ApoE−/− mice with high-fat diet, and the levels of lncRNA MALAT1 in mouse arterial tissue were detected by RT-qPCR. Cell model was established by treating human umbilical vein endothelial cells (HUVECs) with ox-LDL, and the levels of EndMT markers, such as CD31, vWF, α-SMA and Vimentin and lncRNA MALAT1 levels were detected and their correlations were analyzed. The role of MALAT1 in EndMT and its dependence on Wnt/β-catenin signaling pathway was further detected by knocking down or overexpressing MALAT1.ResultsMALAT1 was upregulated in high-fat food fed ApoE−/− mice. HUVECs treated with ox-LDL showed a significant decrease in expression of CD31 and vWF, a significant increase in expression of α-SMA and vimentin, and upregulated MALAT1. An increased MALAT1 level facilitated the nuclear translocation of β-catenin induced by ox-LDL. Inhibition of MALAT1 expression reversed nuclear translocation of β-catenin and EndMT. Moreover, overexpression of MALAT1 enhanced the effects of ox-LDL on HUVEC EndMT and Wnt/β-catenin signaling activation.ConclusionsOur study revealed that the pathological EndMT required the activation of the MALAT1-dependent Wnt/β-catenin signaling pathway, which may be important for the onset of atherosclerosis.Trial registrationNot applicable.

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