Vitamin D reduces oxidative stress-induced procaspase-3/ROCK1 activation and mp release by placental trophoblasts

Abstract

Context: Increased microparticle (MP) shedding by placental trophoblasts contributes to maternal vascular inflammatory response and endothelial dysfunction in preeclampsia. Vitamin D has beneficial effects in pregnancy; however, its effect on trophoblast MP release has not been investigated. Objective: To investigate if Vitamin D could protect trophoblasts from oxidative stress-induced MP release. Design: Placental trophoblasts were isolated from uncomplicated and preeclamptic placentas. Effects of Vitamin D on MP release induced by oxidative stress inducer CoCl2 were studied. Main Outcome Measures: Annexin V+ MPs were assessed by flow cytometry. Expression of caveolin-1, endothelial nitric oxide synthase (eNOS), procaspase-3, cleaved caspase-3, and Rho-associated coiledcoil protein kinase 1 (ROCK1) in trophoblasts and trophoblast-derived MPs were determined by Western blot. Results: Trophoblasts from preeclamptic pregnancies released significantly more MPs than cells from uncomplicated pregnancies (P , 0.01). CoCl2-induced increase in MP release was associated with upregulation of caveolin-1 and downregulation of eNOS expression in trophoblasts (P , 0.05), which could be attenuated by 1,25(OH)2D3. Moreover, 1,25(OH)2D3 could also inhibit CoCl2-induced procaspase-3 cleavage and ROCK1 activation in trophoblasts. Consistently, CoCl2-induced upregulation of procaspase-3, cleaved caspase-3, and ROCK1 expression in trophoblast-derived MPs were also reduced in cells treated with 1,25(OH)2D3. Conclusions: Placental trophoblasts from preeclamptic pregnancies released more MP than cells from uncomplicated pregnancies. Oxidative stress-induced increase in MP shedding is associated with upregulation of caveolin-1 and downregulation of eNOS expression in placental trophoblasts. Inhibition of caspase-3 cleavage and ROCK1 activation, together with upregulation of eNOS expression, could be the potential cellular/molecular mechanism(s) of Vitamin D protective effects on placental trophoblasts.