Curcumin Improves Cardiac Fibrosis By Inhibiting The Endothelial-Mesenchymal Transition Through NRF2-DDAH-ADMA-NO Pathway

Background:Myocardial remodeling induced by myocardial fibrosis plays a strinkly role in the continuous development of heart failure.Endothelial-Mesenchymal Transition(EndMT),participated by many factors,is one of the important mechanisms of myo-cardial fibrosis.The nuclear factor NF-E2-related factor(NF-E2-relatedfactor2,NRF2),a key factor regulated in cellular oxidative stress response,is regulated by Keap1 and then regulates the expression of oxidized proteins via the interaction with the antioxi-dant response elements(ARE).It is named the Keapl-NRF2-ARE signaling pathway.Asymmetric dimethyl arginine(ADMA),as an endogenous inhibitor of NOS,reduces the synthesis of NO,leading to the endothelial insufficiency.Cellular ADMA level is directly controlled by its metabolic enzyme,dimethyl arginine dimethylamino hydro-lase(DDAH).NRF2 can regulates the DDAH level and increases the NO synthe-sis.Accumulated evidence has uncovered that Curcumin has many functions,including anti-oxidative stress,alleviating inflammatory response and protecting cardiovascular system,is considered as a potential drug for the treatment of myocardial fibrosis.How-ever,the role of Cur in the inhibition of myocardial fibrosis and its role in the NRF2-DDAH-ADMA-NO pathway and EndMT during the myocardial fibrosis,thus far,has been rarely reported yet.Objectives:Umbilical vein endothelial cells and rat myocardial fibrosis models were used to investigate the role of Cur in NRF2-DDAH-ADMA-NO pathway and EndMT during myocardial fibrosis.MethodsAt the cellular level:1)The effect of ADMA on cell phenotype during EndMT and DDAH,NOS,NO was observed in the umbilical vein endothelial cells predisposed of TGF.2)umbilical vein endothelial cells treated by transforming growth factor-?(TGF-?)correspondently were divided into the following four groups:control group,Nrf overexpression group and Nrf overexpression+ DDAH knockdown group.The change of the cell phenotype during EndMT and the effect on ADMA and DDAH were detected.3)NRF2 was overexpressed or inhibited correspondently in umbilical vein endothe-lial cells pre-treated with TGF,and subsequently the effect of Cur on EndMT,NRF2 and DDAH were performed.At the animal level:Myocardial fibrosis rats were treated with Cur,then the myocardial fibrosis indi?cators such as collagen ? and collagen ?,cell phenotypic alteration during EndMT and the effect on DDAH,ADMA,eNOS were detected.Results:At the cellular level:1)ADMA decreased the expression of CD31 in EndMT cells as well as NOS and NO,whereas increases the expression of vimentin and ?-SMA.2)In the Nrf-overexpressed group,treating with the TGF-?,the expression of DDAH and VE-cadherin during EndMT were increased,meanwhile ADMA and vimentin??-SMA expression were decreased.Compared with the Nrf-overexpressed group,the expressin of DDAH and VE-cadherin involved EndMT,and CD31 expression were declined while ADMA and vimentin??-SMA were elevated in the Nrf over-expression+DDAH silenced group.3)Cur treatment increased the expression of NRF2,DDAH,VE-cadherin and CD31,while the expression of vimentin and ?-SMA were decreased in progress of EndMT in umbilical vein endothelial cells.Compared with the control group,VE-cadherin,CD31,NRF2,and DDAH were decreased while vimentin and ?-SMA were increased in the Nrf inhibited group.At the animal level:Cur treatment decreased the expression of collage ?/?,vimentin,?-SMA and ADMA,while increased VE-cadherin,CD31,NRF2,DDAH,NOS and NO ex-pression.Conclusion:At the cellular level:1)ADMA promotes the process of EndMT through the DDAH-ADMA-NO pathway.2)NRF2 inhibits the process of EndMT by interferng with DDAH.The NRF2-DDAH-ADMA-NO signaling pathway is involved in EndMT.3)Cur inhibits endothelial cells EndMT through NRF2-DDAH-ADMA-NO pathway At the animal level:Cur supresses EndMT during myocardial fibrosis through NRF2-DDAH-ADMA-NO pathway in the rat modelSummary:Curcumin improves cardiac fibrosis by inhibiting the endothelial-mesenchymal transition through NRF2-DDAH-ADMA-NO pathway.This study provides a basis for further research and treatment of myocardial fibrosis.