Peroxisome proliferator-activated receptor gamma(PPARγ) mediates porcine angiogenesis through VEGF signals

【摘要】：Peroxisome proliferator-activated receptor gamma(PPARγ) plays a vital role in placental development of mice and human,but its role and mechanism in pig placentation has not been reported.In the present study,PPARγ expression were investigated in uterus-placenta tissues which were collected from sows on gestation days(GD) 25,40 and 70 using real-time quantitative polymerase chain reaction(qPCR),Western blot and immunohistochemistry(IHC).And PPARγ over-expression and deficience were performed in the porcine vascular endothelial cells(VECs) for possible role and mechanism using pIC-neo mammal expression system and CRISPR/Cas9 genome editing system,respectively.Then the angiogenic potential of modified VECs were determined using ICELLegance assay,woud healing assay and capillary-like tube formation assay,followed by determination of the mRNA levels of angiogenic factors,including HIFs-VEGF and angiopoietins signals using qPCR.Results showed that the level of PPARγ mRNA was higher in fetal placenta than that in maternal endometrium on the matched GD40 and 70.In maternal endometrium,expression of PPARγ mRNA was decreased on GD25 and 40 when compared to that of the GD70;in fetal placenta,the level of PPARγ mRNA was also higher on GD40 than that of the GD25,and kept a high level on GD70.The expression of PPARγprotein had a similar trend as its mRNA,kept a higher level on GD40 when compared to those of the GD25 and 70 in both maternal endometrium and fetal placenta.Meanwhile,PPARγ protein was mainly located in the endometrial glandular epithelium and trophoblasts,vascular endothelium and amniotic chorion epithelial cells,with a highest expression in trophoblasts on GD40.In vitro,PPARγ deficience inhibited VECs proliteration and migration,and abrogated the tubes formation.The mRNA levels of HIF1α,HIF2α,VEGF188,Flt1 and Ang-1 were significantly up-regulated in PPARγ over-expression VECs,and Ang-2 with down-regulation.Whereas,the mRNA levels of VEGF isoforms and their receptors were down-regulated in PPARγ null VECs,but HIFs and angiopoietins with insignificantly change.These results suggest that PPARγmediates porcine angiogenesis through VEGF signals,adjustment of VEGF transcription and interaction with their receptors.