miR-130b-3p is high-expressed in polycystic ovarian syndrome and promotes granulosa cell proliferation by targeting SMAD4

•miR-130b-3p was high-expressed while SMAD4 was low-expressed in polycystic ovarian syndrome.•SMAD4 was directly targeted by miR-130b-3p.•Elevated miR-130b-3p/reduced SMAD4 promoted cell viability and proliferation, inhibited apoptosis in PCOS.•Reduced miR-130b-3p inhibited cell viability and proliferation, promoted apoptosis in PCOS.•Reduced miR-130b-3p could reverse the effect of SMAD4 silencing on PCOS.