The Role Of P53 In Atrial Fibrosis Induced By Crosstalk Between Ang? Signaling Pathway And PPAR-gamma Signaling Pathway

Objective:(1)To validate the effects of Angiotensin ?(Ang?)signaling pathway and Peroxidase proliferator activated receptor-gamma(PPAR-?)signaling pathway on atrial fibrosis in vitro experiment;(2)To validate there was crosstalk between Ang? signaling pathway and PPAR-gamma signaling pathway in atrial fibrosis in vitro experiment,P53 protein may be a key factor in the crosstalk.Methods:The primary atrial fibroblasts of suckling mice were cultured and passaged in vitro,and the second to third generation cells were taken for experiment.Cells were divided into four groups:(1)Negative control group(CON);(2)Ang? group(Ang);(3)Ang?+p53 inhibitor pifithrin-alpha group(PFT);(4)Ang?+Pioglitazone group(PIO).Cell Counting Kit-8 was used to detect the proliferation of fibroblasts.Western Blot was used to detect Angiotensin type 1 receptor(AT1R)?Extracelluar signal-regulated kinase1/2(ERK1/2)?Transforming growth factor-?1(TGF-?1)? Connective tissue growth factor(CTGF)? P53 ? PPAR-? ?Phosphatidylinositol 3-kinase(PI3K)?Protein kinase B(AKT)?Type ? collagen(Collagen ?)?Type ? collagen(Collagen III)protein Expression.Real-Time PCR was used to detect the mRNA expression of p53?collagen ? and collagen ?.Results:(1)Compared with the CON group,the phosphorylation of ERK1/2 protein was increased in the Ang group(P<0.01),the expression of AT1R?TGF-?1?CTGF?P53 protein were increased(P<0.01),and the expression of PPAR-? protein was decreased(P<0.01).The phosphorylation degree of PI3 K protein decreased(P<0.05),the phosphorylation degree of AKT protein decreased significantly(P<0.01),the expression of Collagen ? protein increased(P<0.05),and the expression of Collagen III protein increased(P<0.01),p53 mRNA expression increased(P<0.05),collagen ? mRNA expression increased(P<0.01),collagen ? mRNA expression increased(P<0.05),atrial fibroblasts increased(P<0.01);Compared with CON group,the phosphorylation of ERK1/2 protein in PFT group and PIO group was enhanced(P<0.01),the expression of AT1R?CTGF protein were significantly increased(P<0.01),and the expression of TGF-?1 protein was increased(P<0.05),the expression of P53 protein was decreased(P<0.01),in PFT group,PPAR-? protein expression decreased(P<0.01),PI3 K protein phosphorylation decreased(P<0.05),AKT protein phosphorylation decreased significantly(P<0.01),and in PIO group,PPAR-? protein expression increased(P<0.05),the phosphorylation degree of PI3 K protein was enhanced(P<0.01),and the phosphorylation degree of AKT protein was significantly enhanced(P<0.01),the expression of Collagen ??Collagen III protein were also significantly decreased in PFT group?PIO group(P<0.01),the expression of p53?collagen ??collagen ? mRNA were decreased(P<0.01),and the proliferation of atrial fibroblasts were decreased(P<0.01).(2)Compared with Ang group,the phosphorylation of ERK1/2 protein in PFT group and PIO group was significantly decreased(P<0.01),the expression of AT1R?CTGF and P53 protein were significantly decreased(P<0.01),and the expression of TGF-?1 protein was decreased(P<0.05),the expression of PPAR-? protein was increased(P<0.01),the phosphorylation of PI3K?AKT protein in PIO group were decreased(P<0.01),the expression of Collagen ??Collagen III protein were also significantly decreased in PFT group?PIO group(P<0.01),the expression of p53?collagen ??collagen ? mRNA were decreased(P<0.01),and the proliferation of fibroblasts in PFT group and PIO group were decreased(P<0.01).Conclusions:(1)Ang? promotes atrial fibrosis by up-regulating its downstream AT1R?ERK1/2 ? TGF-?1 and CTGF signaling molecules and inhibiting the PPAR-?/PI3K/AKT signaling pathway;(2)PPAR-? attenuates atrial fibrosis by activating PI3K/AKT and inhibiting the Ang?/AT1R/ERK1/2/TGF-?1/CTGF signaling pathway;(3)There is a crosstalk between the Ang? signaling pathway and the PPAR-? signaling pathway in atrial fibrosis,and the P53 protein may be its crosstalk factor.