Neuroprotective effects of leptin have been shown in mouse model of cerebral ischemia/reperfusion injury and primary cortical neuronal culture with oxygen-glucose deprivation (OGD), while the underlying mechanisms are less understood. In the present study, we investigated whether leptin modulated mitochondrial function through JAK2/STAT3 in vivo mouse model of transient middle cerebral artery occlusion (MCAO) and in OGD-challenged primary neuronal cultures. JAK2/STAT3; mitochondrial biogenesis markers (PGC-1α); and apoptosis-associated proteins (caspase-3, BCL-2, BCL-XL, and cytochrome c) were detected by western blotting and reverse transcription-polymerase chain reaction at 1 h before and after ischemia/reperfusion. P-STAT3 and PGC-1α in neurons and astrocytes were detected. Moreover, mitochondrial morphology of the ischemic ipsilateral penumbra is examined using transmission electron microscopy. Primary cerebral cortical neurons were evaluated for viability, mitochondrial membrane potential (MMP), and apoptosis to assess whether dose-dependent neuroprotective effects of leptin during OGD were mitigated by the JAK2/STAT3 inhibitor AG490. Leptin activated JAK2/STAT3 signaling in neurons and astrocytes distributed in the ischemic ipsilateral penumbra, with peak p-STAT3 levels observed at 1 h after reperfusion. Leptin increased PGC-1α, BCL-2, and BCL-XL protein levels, cell viability, and MMP and decreased apoptosis both in vitro and in vivo; these effects were reversed by AG490 treatment. Our findings suggest that leptin-mediated neuroprotective effects in tMCAO may peak at 1 h to induce the transcription of its target gene PGC-1α, stabilization of MMP, inhibition of mitochondrial permeability transition pore opening, release of cytochrome c, and apoptosis.

中文翻译：

---

瘦素通过 JAK2/STAT3/PGC-1 介导的线粒体功能调节对脑缺血的神经保护作用。

瘦素的神经保护作用已在脑缺血/再灌注损伤小鼠模型和缺氧葡萄糖剥夺 (OGD) 的原代皮质神经元培养中显示出来，但其潜在机制尚不清楚。在本研究中，我们研究了瘦素是否通过 JAK2/STAT3 体内瞬时大脑中动脉闭塞 (MCAO) 小鼠模型和 OGD 挑战的原代神经元培养物来调节线粒体功能。JAK2/STAT3；线粒体生物发生标记（PGC-1α）；在缺血/再灌注前后 1 小时，通过蛋白质印迹和逆转录聚合酶链反应检测细胞凋亡相关蛋白（caspase-3、BCL-2、BCL-XL 和细胞色素 c）。在神经元和星形胶质细胞中检测到 P-STAT3 和 PGC-1α。此外，使用透射电子显微镜检查缺血同侧半影的线粒体形态。评估原代大脑皮层神经元的活力、线粒体膜电位 (MMP) 和细胞凋亡，以评估 JAK2/STAT3 抑制剂 AG490 是否减轻了 OGD 期间瘦素的剂量依赖性神经保护作用。瘦素激活分布在缺血同侧半暗带的神经元和星形胶质细胞中的 JAK2/STAT3 信号传导，在再灌注后 1 小时观察到峰值 p-STAT3 水平。瘦素增加了 PGC-1α、BCL-2 和 BCL-XL 蛋白水平、细胞活力和 MMP，并减少了体外和体内的细胞凋亡；这些影响被 AG490 治疗逆转。