Analysis of astrocyte response mechanism after brain injury

众所周知，脑损伤可激活星形胶质细胞，然而，尚不清楚它们是如何被调节以对局灶性脑损伤表现出定向反应的。本研究表明，脑损伤后星形胶质细胞P2Y1受体下调可加速星形胶质细胞反应和神经保护。抑制或敲除P2Y1受体可加速体外星形胶质细胞反应。P2Y1受体敲除（P2Y1KO）小鼠在脑损伤后早期星形胶质细胞激活加速，选择性敲除P2Y1受体使星形胶质细胞再生的死亡神经元数量减少。我们的数据强调P2Y1受体介导的脑损伤后星形胶质细胞反应对神经保护作用至关重要。

Brain injury is known to activate astrocytes, however, it is unclear how they are regulated to show an oriented response to the focal brain injury. Here we demonstrate that down-regulation in astrocytic P2Y1 receptor accelerates astrocyte responses and neuroprotection after brain injury. Inhibition or knockout of P2Y1 receptor accelerated astrocyte reaction in vitro. P2Y1 receptor knockout (P2Y1KO) mouse showed accelerated astrocyte activation at early phase after brain injury and reduced a number of dead neurons which were reproduced by selective knockout of P2Y1 receptor in astrocytes. Our data highlight P2Y1 receptor-mediated-astrocyte reaction after brain injury that is essential for neuroprotective action.