b3-adrenergic agonist counters oxidative stress and Na1 -K1 pump inhibitory S-glutathionylation of placental cells: implications for preeclampsia

Oxidative stress from placental ischemia/reperfusion and hypoxia/reoxygenation (H/R) in preeclampsia is accompanied by NaþKþ pump inhibition and S-glutathionylation of its b1 subunit (GSS-b1), a modification that inhibits the pump. b3-adrenergic receptor (b3-AR) agonists can reverse GSS-b1. We examined the effects of the agonist CL316,243 on GSS-b1 and sources of H/R-induced oxidative stress in immortalized first-trimester human trophoblast (HTR-8/SVneo) and freshly isolated placental explants from normal-term pregnancies. H/R increased GSS-b1 and, reflecting compromised a1/b1 subunit interaction, reduced a1/b1 pump subunit coimmunoprecipitation. H/R increased p47phox/p22phox NADPH oxidase subunit coimmunoprecipitation, reflecting membrane translocation of cytosolic p47phox that is needed to activate NADPH oxidase. Fluorescence of O2"¢--sensitive dihydroethidium increased in parallel. H/R increased S-glutathionylation of endothelial nitric oxide synthase (GSS-eNOS) that uncouples nitric oxide synthesis toward the synthesis of O2"¢- and reduced trophoblast migration. Oxidative stress induced by tumor necrosis factor a increased soluble fms-like tyrosine kinase receptor 1 (sFlt-1) trophoblast release, a marker of preeclampsia, and reduced trophoblast integration into endothelial cellular networks. CL316,243 eliminated H/R-induced GSS-b1 and decreases of a1/b1 subunit coimmunoprecipitation, eliminated NADPH oxidase activation and increases in GSS-eNOS, restored trophoblast migration, eliminated increased sFlt-1 release, and restored trophoblast integration in endothelial cell networks. H/R-induced GSS-b1, a1/b1 subunit coimmunoprecipitation, and NADPH oxidase activation of placental explants reflected effects of H/R for trophoblasts and CL316,243 eliminated these changes. We conclude a b3-AR agonist counters key pathophysiological features of preeclampsia in vitro. b3 agonists already in human use for another purpose are potential candidates for repurposing to treat preeclampsia.