The Roles And Mechanisms Of PPAR? And GATA Family Interaction On Myocardial Differentiation

BackgroundPeroxisome proliferator-activated receptors(PPARs)are ligand-dependent nuclear transcription factors that belong to the type II nuclear receptor superfamily.Current researches indicated that PPARs family have three members:PPARa,PPAR?/? and PPAR?.They are involved in regulating various metabolic processes in different cells.PPARs can be activited when bind to ligands,thereby they form heterodimers with the retinoic acid receptor RXR,and then bind to the specific DNA binding element PPRE in the promoter region of the target genes,and finally regulate the transcription of target genes.It has been shown that PPAR? plays an important role in glycometabolism by regulating the expression of target genes or influencing the activity of transcription factors,kinase signaling pathway and so on.Many studies have shown that PPAR? has a protective effect on cardiovascular disease,but its specific molecular mechanism is not completely clear.The GATA family are transcription factors that contain zinc finger structure,of which six members have been known.Among them,GATA4 and GATA6 are important transcription factors that regulate the expression and cardiac differentiation of cardiac gene.Our previous studies showed that one of the PPARs family members PPARa combined with GATA6,which could recruit PcG family proteins to form a complex,and inhibited the differentiation of P19CL6 cells into cardiomyocytes.PPAR?/? interacts with GATA4 or GATA6,which affects the differentiation of P19CL6 cells into cardiomyocytes.Based on the similarity of the structure and function of proteins in the same family,we speculate that PPAR? may also interact with the GATA family to affect myocardial differentiation.In order to verify this speculation,we conducted this research.PurposeThe aim of this study is to explore the effects of PPAR? with the members of GATA family proteins GATA4 and GATA6 on myocardial differentiation,which will be helpful to provide theoretical basis for cardiovascular diseases at the molecular level.Methods1.Induced differentiation experiments were used to verify the effect of PPAR?,GATA4,GATA6 alone or their co-effect on myocardial differentiation in P19CL6 cells and E14TG2a cells.2.Protein Co-immunoprecipitation(Co-IP)experiments were used to verify whether PPAR? interacts with GATA4 or GATA6 in vivo.3.GST pull-down experiments were used to verify whether PPAR? interacts with GATA4 or GATA6 in vitro.4.Luciferase Assay were used to verify the effect of PPAR?,GATA4,GATA6 alone or their co-effect on the promoter activity of ?-MHC,which is a marker gene of cardiomyocyte.Results1.The results of induced differentiation experiments showed that:(1)PPAR?,GATA4 and GATA6 promoted the differentiation of P19CL6 cells into myocardium when they acted alone or collectively;compared with their respective effects,when PPAR? worked with GATA4 or GATA6 collaboratively,the promotion effects of myocardial differentiation were not obvious.(2)When PPAR?,GATA4 or GATA6 acted alone,they could promote the differentiation of E14TG2a cells into cardiomyocytes;when PPAR? worked with GATA4 or GATA6 collectively,the promotion effects were not obvious.2.The results of protein Co-immunoprecipitation experiments showed that PPAR?could combine with GATA4 or GATA6 to form protein complexes in the cell.3.GST pull-down experiments indicated that PPAR? could combine with GATA4 or GATA6 through specific domains.4.Luciferase Assay results indicated that PPAR?,GATA 4 or GATA 6 alone could activate the promoter of ?-MHC,and when PPAR? worked with GATA4 or GATA6 collectively could also promote the activity of ?-MHC promoter.ConclusionPPAR? could combine with GATA4 or GATA6 through specific domains to form protein complexes,which regulate the process of myocardial differentiation.