The Role Of LncRNA XR007793 In Vascular Smooth Muscle Cell Proliferation Induced By High Cyclic Strain

Abnormal proliferation of vascular smooth muscle cells(VSMCs)plays an important role in the development of cardiovascular diseases.Cyclic strain induced by pulse blood flow is an important factor in modulating VSMC proliferation.In hypertension and some other vascular diseases,vascular walls withstand abnormally high cyclic strain,which could activate mechanical sensors in VSMC,transforming mechanical stimulation signal to biological signal and regulating gene expression and cell functions.However,the mechanical biological mechanisms need to be further clarified.In the field of vascular mechanobiology,most researches focues on the role of protein-coding genes as well as small non-coding microRNAs(miRNA).Whereas the functions of long non-coding RNA(lncRNA)are still in its infant.This study sought to filter the proliferation-related lncRNA by high-throughput screening of gene microarray,study the role of functional lncRNA in VSMC proliferation using siRNA in both static and pathologically elevated cyclic strain and explore the possible downstream signaling molecules.Firstly,we constructed the lncRNA and mRNA expression profiles between spontaneously hypertensive rats(SHR)and wistar kyoto rats(WKY)by high-throughput gene microarray.With the informations of fold change,length feature,coding-non-coding co-expression network(CNC),bioinformatics clusters and IPA analysis,we selected proliferation-related lncRNA XR007793 and the possible downstream signaling molecules,inculding signal transducer and activator of transcription 2(Stat2),cell division cycle associated 8(Cdca8),LIM domain only 2(Lmo2)and interferon regulatory factor(Irf7).Secondly,we downregulated the XR007793 expression by siRNA in static to see if XR007793 get involved in the modulation of VSMC proliferation and the possible downstream signaling molecules in this process.Additionally,we applied 5% physiological cyclic strain and 15% pathological cyclic strain on VSMCs by Flexcell-4000 in vitro and investgated the changes of VSMC proliferation and XR007793 expression.Thus,XR007793 specific siRNA transfection was used to futher study the role of XR007793 in the VSMC proliferation induced by pathologically elevated cyclic strain.Microarray analysis revealed that there are 67 upregulated and 167 downregulated lncRNAs,255 upregulated and 272 downregulated mRNAs in VSMC of SHR compared to WKY.Real time RT-PCR results showed that XR007793 specific siRNA transfection significantly decreased XR007793 expression level.Brdu and WST-1 results revealed that XR007793 specific siRNA transfection delevated VSMC proliferation,along with mRNA level of Stat2 ?Lmo2?Irf7 and protein level of Stat2,suggesting that co-expressed gene Stat2 may participate in the modulation of VSMC proliferation induced by XR007793 specific siRNA transfection in static.Lmo2?Irf7 might also engage in this process.Western blot and WST-1 results showed that pathological cyclic strain remarkably elevated VSMC proliferation compared to 5% physiological cyclic strain.Parallel experiments revealed that the expression level of XR007793 was increased undergoing pathological cyclic strain for 3 h and 6 h,while the expression level of XR007793 was decreased on 24 h,with no significant change on 12 h.To futher study the role of XR007793 in the proliferation of VSMC induced by pathologically-elevated cyclic strain,XR007793 specific siRNA transfection was applied undergoing 15% pathological cyclic strain.Our results showed that XR007793 specific siRNA transfection strain upregulated VSMC proliferation compared to non-sense siRNA transfection undergoing 15% pathological cyclic strain.The expression of Stat2?Cdca8?Lmo2?Irf7 was also deteted by real time RT-PCR and found an increase of Cdca8 mRNA level.These results suggested that Cdca8 might participate in modulating VSMC proliferation by XR007793 undergoing 15% pathological cyclic strain.In summary,we provided the different profiles of lncRNAs between SHR and WKY and revealed XR007793 is closely related to VSMC proliferation.In Static,XR007793 may decrease VSMC proliferation by influencing the expression of Stat2,Lmo2,Irf7.Undergoing 15% pathological cyclic strain,XR007793 may increase VSMC proliferation by influencing Cdca8 expression.These results provide new experimental evidence for the study of mechanobiological mechanism during hypertension and the research of potential targets for hypertension therapy.