Department of Critical Care Medicine, General Hospital of Guangzhou Military Command, Guangzhou, China.
Departement of Pathophysiology, Southern Medical University, Guangzhou, China.
J Cell Physiol. 2019 Apr;234(4):3775-3789. doi: 10.1002/jcp.27143. Epub 2018 Sep 7.
Heatstroke is a devastating condition that is characterized by severe hyperthermia and central nervous system dysfunction. However, the mechanism of thermoregulatory center dysfunction of the hypothalamus in heatstroke is unclear. In this study, we established a heatstroke mouse model and a heat-stressed neuronal cellular model on the pheochromocytoma-12 (PC12) cell line. These models revealed that HS promoted obvious neuronal injury in the hypothalamus, with high pathological scores. In addition, PC12 cell apoptosis was evident by decreased cell viability, increased caspase-3 activity, and high apoptosis rates. Furthermore, 14 differentially expressed proteins in the hypothalamus were analyzed by fluorescence two-dimensional difference gel electrophoresis and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Expression changes in hippocalcin (HPAC), a downregulated neuron-specific calcium-binding protein, were confirmed in the hypothalamus of the heatstroke mice and heat-stressed PC12 cells by immunochemistry and western blot. Moreover, HPAC overexpression and HPAC-targeted small interfering RNA experiments revealed that HPAC functioned as an antiapoptotic protein in heat-stressed PC12 cells and hypothalamic injury. Lastly, ulinastatin (UTI), a cell-protective drug that is clinically used to treat patients with heatstroke, was used in vitro and in vivo to confirm the role of HPAC; UTI inhibited heat stress (HS)-induced downregulation of HPAC expression, protected hypothalamic neurons and PC12 cells from HS-induced apoptosis and increased heat tolerance in the heatstroke animals. In summary, our study has uncovered and demonstrated the protective role of HPAC in heatstroke-induced hypothalamic injury in mice.
中暑是一种严重的疾病，其特征为严重的体温过高和中枢神经系统功能障碍。然而，中暑时下丘脑体温调节中枢功能障碍的机制尚不清楚。在本研究中，我们建立了中暑小鼠模型和 PC12 细胞系的热应激神经元细胞模型。这些模型表明，HS 促进了下丘脑明显的神经元损伤，病理评分较高。此外，PC12 细胞活力降低、caspase-3 活性增加和凋亡率升高表明细胞凋亡明显。此外，通过荧光二维差异凝胶电泳分析了下丘脑的 14 种差异表达蛋白，并通过基质辅助激光解吸电离飞行时间质谱进行了鉴定。通过免疫组织化学和 Western blot 验证了热射病小鼠和热应激 PC12 细胞下丘脑中海马钙结合蛋白（HPAC）这种下调的神经元特异性钙结合蛋白的表达变化。此外，HPAC 过表达和 HPAC 靶向的小干扰 RNA 实验表明，HPAC 在热应激 PC12 细胞和下丘脑损伤中作为一种抗凋亡蛋白发挥作用。最后，乌司他丁（UTI）是一种临床上用于治疗中暑患者的细胞保护药物，我们在体外和体内研究了 HPAC 的作用；UTI 抑制了热应激（HS）诱导的 HPAC 表达下调，保护了下丘脑神经元和 PC12 细胞免受 HS 诱导的凋亡，并提高了中暑动物的耐热性。总之，我们的研究揭示并证实了 HPAC 在中暑诱导的小鼠下丘脑损伤中的保护作用。
