Abstract:Mesenchymal stem cells (MSCs) and their secreted exosomes exert a cardioprotective role in jeopardized myocardium. However, the specific effects and underlying mechanisms of exosomes derived from adipose-derived MSCs (ADMSCs) on myocardial ischemia/reperfusion (I/R) injury remain largely unclear. In this study, ADMSC-derived exosomes (ADMSCs-ex) were administrated into the rats subjected to I/R injury and H9c2 cells exposed to hypoxia/reoxygenation (H/R). Consequently, administration of ADMSCs-ex significantly reduced I/R-induced myocardial infarction, accompanied with a decrease in serum levels of creatine kinase-myocardial band, lactate dehydrogenase, and cardiac troponin I (cTnI). Simultaneously, ADMSCs-ex dramatically antagonized I/R-induced myocardial apoptosis, along with the upregulation of Bcl-2 and downregulation of Bax, and inhibition of Caspase 3 activity in rat myocardium. Similarly, ADMSCs-ex significantly reduced cell apoptosis and the expression of Bax, but markedly increased cell viability and the expression of Bcl-2 and Cyclin D1 under H/R. Furthermore, ADMSCs-ex observably induced the activation of Wnt/β-catenin signaling by attenuating I/R- and H/R-induced inhibition of Wnt3a, p-GSK-3β (Ser9), and β-catenin expression. Importantly, treatment with Wnt/β-catenin inhibitor XAV939 partly neutralized ADMSC-ex–induced antiapoptotic and prosurvival effects in H9c2 cells. In conclusion, we confirmed that ADMSCs-ex protect ischemic myocardium from I/R injury through the activation of Wnt/β-catenin signaling pathway.

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We study heteroclinic solutions of a generalized Frenkel-Kontorova model. Using the methods of Rabinowitz and Stredulinsky, we prove that if the rotation vector of the configuration is rational and if there is an adjacent pair of periodic configurations, then there is a solution that is heteroclinic in one fixed direction and periodic in other directions. Furthermore, if the above heteroclinic solutions have an adjacent pair, then there is a solution that is heteroclinic in two directions and periodic in other directions. The procedure can be repeated to produce more complex solutions. Thus we obtain a variational construction for these minimal and Birkhoff solutions.and κ( ) → 0 as → 0. By Proposition 3.1,by (3.50)-(3.52),Thus letting k → ∞ shows thatTo construct solutions heteroclinic in i 1 and i 2 , we need another renormalized functional J 2 (u). For u ∈Γ 2 and i ∈ Z, set J 2,i (u) = J 1 (τ 2 −i u) − c 1 , J 2;p,q (u) = q i=p J 2,i (u),

Background: Hypoxia is a well-known factor in the promotion of apoptosis, which contributes to the development of numerous cardiac diseases, such as heart failure and myocardial infarction. Inhibiting apoptosis is an important therapeutic strategy for the treatment of related heart diseases caused by ischemia/hypoxic injury. Previous studies have demonstrated that BAG3 plays an important role in cardiomyocyte apoptosis and survival. However, the role of BAG3 in hypoxia-induced cardiomyocyte apoptosis remains to be clarified. Here, we demonstrate that BAG3 is induced by hypoxia stimuli in cultured cardiomyocytes. Methods: BAG3 expression level was measured in H9c2 cells treated with hypoxia for 48 h. Cell proliferation and apoptosis were tested using MTT assay and Annexin V FITC-PI staining assay, respectively. The mRNA or protein expression level of BAG3, LC3-I, LC3-II, Atg5, NF-κB p65 and phosphorylated NF-κB p65 were assessed by qRT-PCR and western blot assay, respectively. Resluts: Overexpression of BAG3 inhibited cell apoptosis and promoted proliferation in hypoxia-injured H9c2 cells. Furthermore, autophagy and NF-κB were activated by BAG3 overexpression, and the NF-κB inhibitor PDTC could inhibit the activation of autophagy induced by BAG3 overexpression. In addition, the autophagy inhibitor 3-MA partly impeded the inhibitory effect of BAG3 on hypoxia-induced cardiomyocyte apoptosis. Conclusion: these results suggested that overexpression of BAG3 promoted cell proliferation and inhibited apoptosis by activating autophagy though the NF-κB signaling pathway in hypoxia-injured cardiomyocytes.

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