Tongxinluo Activates PI3K/AKT Signaling Pathway to Inhibit Endothelial Mesenchymal Transition and Attenuate Myocardial Fibrosis after Ischemia-Reperfusion in Mice

Objective To investigate the potential role of Tongxinluo(TXL)in attenuating myocardial fibrosis after myocardial ischemia-reperfusion injury(MIRI)in mice.Methods A MIRI mouse model was established by left anterior descending coronary artery ligation for 45 min.According to a random number table,66 mice were randomly divided into 6 groups(n=11 per group):the sham group,the model group,the LY-294002 group,the TXL group,the TXL+LY-294002 group and the benazepril(BNPL)group.The day after modeling,TXL and BNPL were administered by gavage.Intraperitoneal injection of LY-294002 was performed twice a week for 4 consecutive weeks.Echocardiography was used to measure cardiac function in mice.Masson staining was used to evaluate the degree of myocardial fibrosis in mice.Qualitative and quantitative analysis of endothelial mesenchymal transition(EndMT)after MIRI was performed by immunohistochemistry,immunofluorescence staining and flow cytometry,respectively.The protein expressions of platelet endothelial cell adhesion molecule-1(CD31),α-smoth muscle actin(α-SMA),phosphatidylinositol-3-kinase(PI3K)and phospho protein kinase B(p-AKT)were assessed using Western blot.Results TXL improved cardiac function in MIRI mice,reduced the degree of myocardial fibrosis,increased the expression of CD31 and inhibited the expression ofα-SMA,thus inhibited the occurrence of EndMT(P<0.05 or P<0.01).TXL significantly increased the protein expressions of PI3K and p-AKT(P<0.05 or P<0.01).There was no significant difference between TXL and BNPL group(P>0.05).In addition,the use of the PI3K/AKT pathway-specific inhibitor LY-294002 to block this pathway and combination with TXL intervention,eliminated the protective effect of TXL,further supporting the protective effect of TXL.Conclusion TXL activated the PI3K/AKT signaling pathway to inhibit EndMT and attenuated myocardial fibrosis after MIRI in mice.

27-Hydroxycholesterol-induced EndMT acts via STAT3 signaling to promote breast cancer cell migration by altering the tumor microenvironment

Objective:The endothelial to mesenchymal transition(EndMT)plays a major role in cancer metastasis by regulating the complexity of the tumor microenvironment(TME).Here,we investigated whether 27-hydroxycholesterol(27 HC)induces EndMT in endothelial cells(ECs).Methods:EndMT markers in the human microvascular endothelial cell-1(HMEC-1)cell line and human umbilical vein endothelial cells(HUVECs)stimulated with 27 HC were evaluated with Western blot.Epithelial to mesenchymal transition(EMT)markers in breast cancer(BC)cells cultured in conditioned medium were investigated with quantitative real time polymerase chain reaction(qRT-PCR).The MMP-2 and MMP-9 mRNA expression and activity were detected with qRT-PCR and gelatin zymography assays,respectively.The effect of activated STAT3 on 27 HC-induced EndMT was validated by Western blot,immunofluorescence staining,and cell transfection assays.The migration ability of BC cells was evaluated with Transwell assays.Results:We found that 27 HC induced EndMT in HMEC-1 and HUVECs,and 27 HC-induced EndMT facilitated EMT and BC cell migration.The 27 HC-induced EMT of BC cells also promoted EndMT and HUVEC migration.Investigation of the underlying molecular mechanisms revealed that STAT3 knockdown repressed EndMT in HUVECs as well as migration in BC cells induced with 27 HC.In addition,C646 and resveratrol,inhibitors of STAT3 acetylation,repressed the expression of Ac-STAT3,p-STAT3,and EndMT markers in HUVECs exposed to 27 HC;these HUVECs in turn attenuated the migration ability of BC cells in 27 HC-induced EndMT.Conclusions:Cross-talk between 27 HC-induced EndMT and EMT was observed in the TME.Moreover,activation of STAT3 signaling was found to be involved in 27 HC-induced EndMT.