Peroxisome proliferator-activated receptor γ mediates porcine placental angiogenesis through hypoxia inducible factor-, vascular endothelial growth factor- and angiopoietin-mediated signaling

Abstract

Peroxisome proliferator-activated receptor (PPAR) γ has been reported to be implicated in placentation in mice. Previous studies have demonstrated that PPARγ is also expressed in porcine placenta, primarily localized in vascular endothelial cells (VECs). The present study aimed to investigate the roles of PPARγ during porcine placental angiogenesis and examine the molecular mechanisms involved in its actions. VECs were incubated with the PPARγ agonist rosiglitazone and the antagonist T0070907, and their angiogenic potential was evaluated using cellular impedance, wound healing and tube formation assays. Reverse transcription-quantitative polymerase chain reaction was used to assess the mRNA expression levels of angiogenic factors, including hypoxia-inducible factors (HIFs), vascular endothelial growth factor (VEGF) isoforms, VEGF receptors (VEGFRs) and angiopoietins (Angs). The results demonstrated that the adhesive, proliferative and migratory capabilities of VECs were potentiated by rosiglitazone and suppressed by T0070907. Notably, tube formation was invariably promoted during PPARγ activation and blockade. The mRNA expression levels of HIF1α, HIF2α, VEGFR2, VEGF188 and Ang-1 were revealed to be upregulated following treatment of VECs with rosiglitazone, whereas they were downregulated following treatment with T0070907. However, the mRNA expression levels of placental growth factor and VEGF120 were consistently downregulated following PPARγ activation and blockade, whereas VEGF164 mRNA levels remained unaltered. The results of the present study suggested that PPARγ may mediate porcine placental angiogenesis, by interfering with HIF-, VEGF- and angiopoietin-mediated signaling pathways.

Spatiotemporal heterogeneity of PPARγ expression in porcine uteroplacenta for regulating of placental angiogenesis through VEGF‐mediated signalling

“…Among them, the adiporegulatory factor PPARγ may be a key factor. Our and others previous studies have illustrated that PPARγ is expressed in porcine placenta with unaltered expression patterns from GD15 to GD30 (Blitek & Szymanska, 2019;Zhang et al, 2017). However, the location and spatiotemporal distribution of PPARγ expression needs further investigation.…”

“…As described in a previous study (Zhang et al., 2017), PUVECs were cultured in RPMI 1640 medium supplemented with 10% foetal calf serum and 100 µg/ml penicillin/streptomycin (Gibco, Thermo Fisher Scientific, Inc.) at 37°C in a 5% CO 2 atmosphere. The PPARγ knockout (PPARγ −/− ) cell model was constructed with a CRISPR/Cas9 system using the pspCas9(BB)‐2A vector (PX458 for GFP expression, PX459 for puromycin selection; Addgene, Beijing Zhongyuan, Ltd.).…”

“…The proliferative ability of PUVECs (negative control cell line and PPARγ −/− cell line) was assessed through a cellular impedance assay (Koval et al., 2015; Zhang et al., 2017). Briefly, prepared cells were seeded into 8‐well E‐plates (ACEA Biosciences, Inc.) at a density of 7,500 cells/well, and their proliferative ability was dynamically monitored using the iCELLigence™ real‐time cell analysis (RTCA) system (ACEA Biosciences, Inc.) at 37°C in a 5% CO 2 atmosphere for 100 hr.…”

“…The migration ability of PUVECs (negative control cell line and PPARγ −/− cell line) was assessed with a scratch‐wound assay (Martinotti & Ranzato, 2020; Zhang et al., 2017). Briefly, cells cultured to 90% confluence were serum‐starved in RPMI 1640 medium for 9 hr.…”

“…As described in a previous study (Zhang et al, 2017), PUVECs were cultured in RPMI 1640 medium supplemented with 10% foetal calf serum and 100 µg/ml penicillin/streptomycin (Gibco, Thermo Fisher Scientific, Inc.) at 37°C in a 5% CO 2 atmosphere.…”