Astrocytic Yes-associated protein attenuates cerebral ischemia-induced brain injury by regulating signal transducer and activator of transcription 3 signaling.

Astrocytic Yes-associated protein (YAP) has been implicated in astrocytic proliferation and differentiation in the developing neocortex. However, the role of astrocytic YAP in diseases of the nervous system remains poorly understood. Here, we hypothesized that astrocytic YAP exerted a neuroprotective effect against cerebral ischemic injury in rats by regulating signal transducer and activator of transcription 3 (STAT3) signaling. In this study, we investigated whether the expression of nuclear YAP in the astrocytes of rats increased significantly after middle cerebral artery occlusion (MCAO) and its effect on cerebral ischemic injury. We used XMU-MP-1 to trigger localization of YAP into the nucleus and found that XMU-MP-1 treatment decreased ischemia/stroke-induced brain injury including reduced neuronal death and reactive astrogliosis, and extenuated release of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Mechanically, XMU-MP-1 treatment suppressed the expression of phospho-STAT3 (P-STAT3). We established an in-vitro oxygen-glucose deprivation/reperfusion (OGD/R) model to simulate an ischemic condition and further explore the function of astrocytic YAP. We found that nuclear translocation of astrocytic YAP in rats could improve cell vitality, decrease the release of inflammatory cytokines and reduce the expression of P-STAT3 in vitro. In contrast, we also found that inhibition of YAP by verteporfin further aggravated the injury induced by OGD/R via STAT3 signaling. In summary, our results showed that nuclear localization of astrocytic YAP exerted a neuroprotective effect after cerebral ischemic injury in rats via inhibition of the STAT3 signaling.