ApoA-1 Inhibits Endothelial Mesenchymal Transition By Promoting TTP-mediated Degradation Of Snail And Slug MRNA

[purpose] The transition of endothelial cells to mesenchymal cells(EndMT)is accompanied by changes in the expression of transcription factors and cytokines,which is closely related to the damage of vascular endothelial cells.According to related research reports,transforming growth factor β1(TGF-β1)plays a key role in inducing the formation of EndMT.Recent studies have found that EndMT can promote the development of atherosclerosis(As).Epidemiological studies have shown that apolipoprotein A-I(ApoA-I)levels are inversely related to cardiovascular disease risk.According to the previous research of our research group and related literature reports,it has been confirmed that ApoA-I shows a significant anti-As effect,and overexpression of ApoA-I can significantly inhibit the progress of As.ApoA-I can inhibit TGF-β1-induced EndMT,but the exact role of ApoA-I in TGF-β1-induced EndMT is not fully understood.Zinc finger protein 36(TTP)can recognize and bind to the corresponding mRNA 3’UTR AU-rich elements(AREs),resulting in increased instability of its corresponding mRNA,promoting its degradation,and studies have found that ApoA-I canupregulate the expression of TTP.Whether ApoA-I regulates other pathways to inhibit TGF-β1-induced EndMT is unclear.Therefore,the purpose of this study is to verifiy whether ApoA-I can regulate the degradation of Snail / Slug mRNA through TTP and inhibit EndMT.[Methods] With or without the addition of ApoA-I(50μg / mL),TGF-β1(10 ng / mL)was used to induce Human Umbilical Vein Endothelial Cells(HUVECs)to establish an EndMT cell model,with HUVECs as the control group,without ApoA-TGF-β1 of I induces HUVECs to form EndMT as TGF-β1 group,and TGF-β1 exogenously added to ApoA-I induces HUVECs to form EndMT as TGF-β1 + ApoA-1 group,and then conduct the following series of experiments.First,the angiogenesis experiment was used to analyze the changes in the cell morphology of the TGF-β1 group and the phenotype and tube type of the TGF-β1 + ApoA-1 group;immunofluorescence was used to detect the changes in the cell phenotype of the TGF-β1 group;In the group,Western Blot technology was used to detect CD31,VE-cadherin,α-SMA,JAK2,p-JAK2,STAT3,p-STAT3,TTP,Snail and Slug protein levels,and PCR technology was used to detect TTP,Snail and Slug mRNA expression levels..Use the luciferase reporter gene experiment to observe whether TTP binds to AREs of Snail mRNA and Slug mRNA 3’UTR;use TTP interfering RNA(TTP siRNA),AG490 and STAT3 interfering RNA(STAT3 siRNA)to interfere with TTP,JAK2 and STAT3,or Inhibition,detect the expression of related proteins and mRNA during ApoA-1 inhibition of TGF-β1-induced EndMT.[Results] 1.ApoA-I inhibits TGF-β1 induced EndMT by reducing Snail and Slug.2.ApoA-I degrades Snail and Slug mRNA through TTP and inhibits EndGF induced by TGF-β1.3.ApoA-I promotes TTP to inhibit EndGF induced by TGF-β1 through JAK2 / STAT3 signaling pathway.[Conclusion]: ApoA-I can inhibit EndMT by promoting the degradation of Snail mRNA and Slug mRNA by TTP,and affect TTP through JAK2/STAT3 signaling pathway.