The Expression Changes Of Tumor-associated Long Non-coding RNAs In Neointimal Formation

Objective: Long non-coding RNA (lncRNA) is a class of ncRNAs withthe length more than200nt, which have no open reading frame (ORF)encoding proteins. Initially, the non-coding transcripts were thought to be"transcriptional noise", which didn’t play any role in cell development andmetabolic processes. Recently, a large numbers of lncRNAs were found ineukaryotic cells, and the specific expressions of these lncRNAs were relatedto cancer and many other diseases. However, their expression profile invascular injury and repair is still unclear.By database retrieval, we screened four tumor-associated lncRNAs:growth arrest specific5(Gas5), nuclear paraspeckle assembly transcript1(Neat1), taurine up-regulated gene1(TUG1) and lnc1385. In this study, weinvestigated the expression changes and the roles of these lncRNAs inneointimal hyperplasia induced by balloon injury.Methods and results:1Establishment of rat models of carotid artery balloon injurySD rats were killed for3,14and28days after the left carotid arteryballoon injury, respectively. The vessel segments were analyzed with HEstaining. The results showed that the neointimal hyperplasia in the injuredarteries occurred after balloon injury for14and28days.2The expression changes of the smooth muscle markers in neointimalhyperplasiaThe frozen segments were homogenized. The lysates containing equalamounts of protein were separated by SDS-PAGE and detected by westernblotting. The expression of smooth muscle differentiation markers SM22α andMYH11were down-regulated, and the expression of proliferation markerPCNA was up-regulated at day3and14after balloon injury. At day28after injury, the expression of SM22αand MYH11decreased.3The expression changes of the lncRNAs in neointimal hyperplasiaTotal RNA isolated from the injured and control vessels was subjected toreverse transcription, and then analyzed by real time PCR. The results showedthat the level of lncRNA Gas5, Neat1v2, TUG1and lnc1385in the vasculartissues progressively elevated after injury3and14days, and weaklydecreased at28days. The results suggest that the expression of these fourlncRNAs is positively correlated with cellular proliferation.Conclusion:1Balloon injury induces neointimal hyperplasia.2Smooth muscle marker genes were down-regulated in the process ofneointimal hyperplasia.3Intimal injury induces the expression of lncRNA Gas5, Neat1v2, TUG1,lnc1385.