Xin-Ji-Er-Kang Inhibits Endothelial-to-mesenchymal Transition In Myocardial Infarction Induced Heart Failure By Regulating The TGF-β/Smad Signaling Pathway

Background: Myocardial infarction（MI）,a serious cardiovascular disease,has long been one of the main causes of disability and death in the global population.As a Chinese herbal formula,Xin-Ji-Er-Kang（XJEK）has been proven to protect heart function in myocardial infarction（MI）mouse models.Aim: To investigate the protective effect of XJEK on heart failure（HF）induced by MI and the molecular mechanisms involved by inhibiting endothelial-to-mesenchymal transition（End MT）and the related mechanism.Methods: Serum and cardiac tissue were collected from patients with HF and healthy people,and the pathological changes of the myocardium between the HF group and the healthy control group were compared by Masson staining.Immunofluorescence（IF）was used to observe whether the End MT occurred in the HF group.Enzyme-linked immunosorbent assay（ELISA）to measure Tumor necrosis factor-α（TNF-α）and Transforming growth factor-β1（TGF-β1）in serum content changes.26 male Kunming（KM）mice survived modeled were randomized divided into three groups: MI group,MI+XJEK group and MI+SB431542 group.The other 16 mice had the identical surgical step but without ligation of the left coronary artery were randomized divided into Sham group and Sham+XJEK group.XJEK was administered via oral gavage for 4 weeks,and its effects on cardiovascular function parameters,cardiac function-related biomarkers and End MT were evaluated.In order to determine the possible potential mechanism of XJEK in the context of End MT and MI-induced HF,the regulatory effects of XJEK on TGF-β/Smad3 pathway were further studied in human umbilical vein endothelial cells（HUVECs）upon the combined challenge of TGF-β1 and TNF-αSmad3 lentiviral transfection was conducted in HUVECs to specifically up-regulate Smad3 gene expression in the context of End MT.Results: Compared to control,serum levels of End MT inducers,TNF-α as well as TGF-β1 were significantly increased in HF patients,and immunostaining analysis revealed a higher End MT event in HF patients.Similarly,we also observed increased End MT during MI-induced HF.Importantly,we found that XJEK significantly improved cardiac dysfunction induced by MI,which probable partly due to the inhibitory effect of XJEK on End MT.A similar effect was observed with SB431542,a potent and selective TGF-β/Smad inhibitor.Additionally,we observed that XJEK inhibited End MT in TGF-β1 and TNF-α induced HUVECs in vitro by inhibiting TGF-β/Smad signaling.In the end,we observed that Smad3 overexpression promoted End MT,and such promotive effect was partially abolished by XJEK.Conclusion: XJEK can have a protective effect on mouse models of HF induced by MI and TGF-β1 and TNF-α-induced HUVECs.Its mechanism may be attributed to the regulation of the TGF-β/Smad signaling pathway to inhibit End MT.