PI3K AND MAPK SIGNALING PATHWAYS ARE INVOLVED IN LEPTIN SURVIVAL EFFECT IN PLACENTAL CELLS UNDER HYPOXIC CONDITION

SALINAS, SEBASTÍAN; CASALE, ROBERTO; DE DIOS, NATALY; JAIME, MARIANA; VARONE, CECILIA L.; RIEDEL, RODRIGO N.; MAYMÓ, JULIETA L.

Mar del Plata

Congreso; LXVII Reunión anual SAIC. SAI. SAFIS 2022; 2022

SOCIEDAD ARGENTINA DE INVESTIGACION CLÍNICA

Leptin acts as a regulatory hormone in the maternal fetal interface. Leptin promotes proliferation and survival of trophoblastic cells, and prevents cellular stress in trophoblastic cells. In this sense, leptin is incremented in different pregnancy pathologies such as preeclampsia, as a compe nsatory response to hypoxia or oxidative stress present in placental cells. As a model of hypoxia we use CoCl2 treatment that stabilizes HIF-1α transcription factor, involved in hypoxia response. In the present study, we evaluated MAPK and PI3K signaling pathway, on leptin actions after CoCl2 treatment. We used Swan-71 cells, a first trimester cytotrophoblast human cell line and human term placental explants. Both cell models were treated with 100 μM PD98059 and 50 nM Wortmannin pharmacological inhibitors of MAPK and PI3K respectively, combined with or without, CoCl2 (100 or 250 μM) in the presence of leptin (100 ng/ml). The expression of Caspase-8 and Cytochrome C was determined by Western blot. Apoptotic DNA fragmentation was determined by the DNA ladder assay, cell proliferation was analyzed by Ki67 expression determined by IF and cell counter, and finally, MTT assay was used to evaluate cell survival. Leptin diminished Caspase-8 and Cytochrome C expression in placental explants under simil-hypoxic condition; the presence of Wortmannin, completely reverted leptin effect on Cytochrome C levels (1.4 ± 0.04). Leptin prevented CoCl2 apoptosis in placental explants determined by DNA ladder assay and this effect was blocked with PI3K signaling pathway inhibitor (1.2 ± 0.3) On the other hand, cell proliferation was diminished after CoCl2 treatment, analyzed by the expression of Ki67 and cell counting. Leptin significantly reversed this effect and Wortmannin blocked leptin proliferative effect in Swan-71 cells (0.84 ± 0.34) under hypoxia stress. Similar results were obtained when analyzing leptin enhanced cytotrophoblast cell survival that was diminished by PD98059 or Wortmannin inhibitors. All these results suggest that HIF-1α stabilization has negative effects on cell survival; and leptin protects trophoblastic cells from the hypoxic condition involving MAPK and PI3K pathways.