Role Of LncRNA Fendrr In Activation And Proliferation Of Cardiac Fibroblasts

Background Atrial fibrillation(Atrialfibrillation,AF)refers to the rules,sequential atrial department normal physiological activity completely,instead of frequency up to300-600 times/min disorderly,uncoordinated tiny vibration wave,so that the lost all effective atrial part or contraction,heart can't pump out the backflow of blood normally,is a very common rapid arrhythmia.Atrial fibrillation is closely related to the occurrence and development of heart failure,and is an important factor leading to cardiac shock,stroke,pulmonary embolism and other fatal diseases.Up to now,the causes of the occurrence and persistence of atrial fibrillation have not been fully explored.Long noncoding RNA as a length of more than 200 nt don't participate in protein-coding RNA,originally thought it do not have any biological significance,with the growing understanding,find its influence chromatin configuration again,biological protein translation,translation and then modify key processes,directly or indirectly affect gene expression in the role.More and more studies have shown that LncRNAs have a certain degree of correlation with the progression and maintenance of many kinds of diseases,including myocardial fibrosis,which to a certain extent proves that LncRNAs can play a potential role in the diagnosis of some diseases.Purpose To clarify the FOXF1 adjacent non-coding developmental regulatory RNA(long non-coding RNA FOXF1 adjacent non-coding developmental regulatory RNA,The expression of LncRNA Fendrr),DNA methyl transferase 3B(DNMT3B)and ras association domain family 1A gene(RASSF1A)in cardiac fibrosis specimens and models,The function of LncRNA Fendrr in the process of activation and proliferation of cardiac fibroblasts was preliminarily clarified,and it was further explained that LncRNA Fendrr may enhance RASSF1A methylation through DNMT3B,thus having a lasting influence on the continuous progress of cardiac fibrosis.Methods SD(Sprague-Dawley)atrial fibrillation animal model of myocardial fibrosis in rats with SD rats left lower abdominal subcutaneous injections isopropyl adrenaline hydrochloride(Isoprenaline Hydrochloride,ISO)method.A total of 100 SD rats without specific pathogen free(SPF)were numbered successively,and divided into normal control group and experimental group by random selection,with 50 rats in each group.SD rats in the experimental group were subcutaneously injected with ISO in the left middle and lower abdomen,and SD rats in the normal control group were subcutaneously injected with the same dose of normal saline in the left middle and lower abdomen.After 14 days of modeling,the animal models were sacrificed and the heart specimens were taken out.The primary myocardial fibroblasts of newborn SD rats were extracted by mixed enzyme digestion and cultured in the medium of 10%fetal bovine serum at 37?and 5%CO₂.The heart specimens obtained in phosphate buffer solution(Phosphatebufferedsalinesolution,PBS)after cleaning,after into universal organization fixed fluid specimen slice,line Hematoxylin-eosin staining method(Hematoxylin-eosinstaining,HE staining),Sirius red staining and Masson staining.Immunohistochemical method was used to observe the expression of DNMT3B,RASSF1A and?-smooth muscle actin(?-SMA).Overexpression plasmids of DNMT3B small interfering RNA(si RNA)and LncRNA Fendrr were constructed and acted on primary cardiac fibroblasts by transient transfection.The expressions of DNMT3B and RASSF1A were detected by immunofluorescence after the primary cardiac fibroblasts were treated with universal cell fixative.The proliferation activity of cardiac fibroblasts was detected by 5-bromodeoxyuridine(Brd U)test,Cell Counting Kit-8(CCK-8)test and thiazole blue(MTT)test.The m RNA expressions of LncRNA Fendrr,DNMT3,RASSF1A and Collagen I(Col1A1)were detected by quantificational rt-PCR.The proteins of tissue and primary cardiac fibroblasts were extracted,and the expressions of DNMT3B,RASSF1A,?-SMA,Col1A1 and mammalian sterile 20-like kinase 1(Mst1)were observed by Western blotting.Results Heart tissue in atrial fibrillation(AF),the expression of LncRNA Fendrr quantity is obviously lower than that of patients with sinus rhythm heart tissue,but relative to the patients with sinus rhythm,atrial fibrillation patients heart tissue in DNMT3B,?-SMA,and the expression of Col1A1 volume increased significantly,HE staining,Sirius red staining and Masson staining also said myocardial tissue in patients with atrial fibrillation in chaos,total collagen hyperplasia significantly.The expression levels of DNMT3B,?-SMA and Col in the ISO treated SD rats were significantly higher than those in the normal control group.He staining,Sirius red staining and Masson staining also showed that the myocardial tissue of the SD rats in the experimental group was disordered and the collagen fiber proliferation was extremely significant in the interstitium.Compared with normal cultured primary cardiac fibroblasts,the proliferation activity of primary cardiac fibroblasts treated with TGF-?1 was significantly increased,the expression of LncRNA Fendrr was decreased,and the expressions of DNMT3B,?-SMA and Col1A1 were increased.The proliferation activity of primary myocardial fibroblasts transfected with LncRNA Fendrr overexpressing plasmid was significantly reduced,and the expressions of DNMT3B,?-SMA and Col1A1 were decreased compared with the no-load plasmid transfected group and the normal group.The expression levels of?-SMA and Col1A1in primary myocardial fibroblasts transfected with DNMT3B-si RNA decreased compared with the negative control group and the normal group.5-nitrogen hetero-2-deoxidation cytidine(5-Azad C)treated with primary cardiac fibroblasts proliferation activity significantly decreased,?-SMA and Col1A1 expression decreased,transfection DNMT3B-si RNA primary myocardial fibroblasts,relative to the negative control group and normal group,the expression of RASSF1A volume increased significantly,5-Azad C treated the original generation of cardiac fibroblasts,expression of RASSF1A volume increased significantly.Atrial fibrillation in patients with cardiac tissue,the expression of RASSF1A quantity is obviously lower than that of patients with sinus rhythm cardiac tissue,the expression of Mst1 quantity is obviously higher than that of patients with sinus rhythm heart tissue,through ISO processing of experimental SD rats,the expression of RASSF1A amount of SD rat heart tissue significantly lower than the normal control group,the expression of Mst1 amount of SD rat heart tissue is significantly higher than normal control group,treated with TGF-beta 1 original generation of cardiac fibroblasts,the expression of RASSF1A volume significantly lower than the normal control group of the original generation of cardiac fibroblasts,The expression level of MST1 was significantly higher than that of the primary myocardial fibroblasts in the normal control group.The expression level of MST1 in the primary myocardial fibroblasts transfected with RASSF1A-si RNA was significantly higher than that of the normal group and the negative control group.The cell proliferation activity was significantly enhanced,and the expressions of?-SMA and Col1A1 were increased.Conclusion In conclusion,this study provides a new idea for the mechanism by which LncRNA Fendrr affects the methylation of RASSF1A by interfering with DNMT3B,and then regulates the proliferation and activation of myocardial fibroblasts and myocardial fibrosis.LncRNA Fendrr can be used as an important target for the regulation of myocardial fibrosis.Therefore,it can be inferred that restoring the epigenetic control of RASSF1A may be a potential therapeutic method for the treatment of myocardial fibrosis,and its targeted regulator can be used as an effective clinical drug to block the development of cardiac fibrosis.