title: Suppression of protein phosphatase 2 differentially modulates VEGF- and FGF2-induced signaling in ovine fetoplacental artery endothelial cells.
abstract: Vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) elicit cellular responses via activation of protein kinases and phosphatases. We have reported that the MEK1/2/ERK1/2 and PI3K/AKT1 pathways are critical for VEGF- and FGF2-stimulated ovine fetoplacental artery endothelial (OFPAE) cell proliferation. We have also shown that protein phosphatase 3 (PPP3) differentially modulates VEGF- and FGF2-stimulated cell proliferation and activation of ERK1/2 and AKT1 in OFPAE cells. Herein, we investigated if protein phosphatase 2 (PPP2) modulated VEGF- and FGF2-induced ERK1/2, AKT1, and p38 MAPK activation and VEGF- and FGF2-stimulated cell proliferation in OFPAE cells. Small interfering RNA (siRNA) specifically targeting human PPP2CA catalytic subunit alpha (PPP2CA) was used to suppress PPP2CA expression in OFPAE cells. When compared with scrambled siRNA, PPP2CA siRNA decreased (p<0.05) PPP2CA protein levels (approximately 70%) and activity (approximately 50%) without altering protein levels of PPP3 catalytic subunit alpha (PPP3CA), nitric oxide synthase 3 (NOS3), ERK1/2, AKT1, and p38 MAPK. FGF2, but not VEGF rapidly (< or =5 min) induced p38 MAPK phosphorylation. Suppression of PPP2CA enhanced (p<0.05) VEGF-induced AKT1, but not ERK1/2 phosphorylation, whereas inhibited (p<0.05) FGF2-induced ERK1/2 and p38 MAPK and slightly attenuated FGF2-induced AKT1 phosphorylation. Suppression of PPP2CA did not significantly affect VEGF- and FGF2-stimulated OFPAE cell proliferation. Thus, suppression of PPP2CA alone differentially modulated VEGF- and FGF2-induced ERK1/2, AKT1, and p38 MAPK activation, without altering VEGF- and FGF2-stimulated cell proliferation in OFPAE cells. These data also suggest that signaling molecules other than ERK1/2, AKT1, and p38 MAPK are important mediators for VEGF- and FGF2-stimulated OFPAE cell proliferation after PPP2CA suppression.
authors.affiliation: Department of Obstetrics and Gynecology, Perinatal Research Laboratories, University of Wisconsin, Madison, WI 53715, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Song
authors.forename: K
authors.initials: K
authors.lastname: Wang
authors.forename: D-B
authors.initials: DB
authors.lastname: Chen
authors.forename: R R
authors.initials: RR
authors.lastname: Magness
authors.forename: J
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000818:Animals; D001158:Arteries / Q000166:cytology*; D002384:Catalysis; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010920:Placenta / Q000098:blood supply* / Q000166:cytology; D011247:Pregnancy; D020033:Protein Isoforms / Q000378:metabolism; D054648:Protein Phosphatase 2 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D012756:Sheep; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D052250:Nitric Oxide Synthase Type III; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D054648:Protein Phosphatase 2
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