Yu Mingchen, Ou Yiqing, Wang Hongmei, Gu Weidong
Department of Orthopedics, Changzhou Seventh People's Hospital, Changzhou, Jiangsu Province, China.
Nantong University, Nantong, Jiangsu Province, China.
Int J Neurosci. 2023 Apr;133(4):389-402. doi: 10.1080/00207454.2021.1923017. Epub 2021 Sep 21.
Secondary spinal cord injury is the inflammatory damage to surrounding tissues caused by activated microglial-mediated neuroinflammatory responses. The nuclear factor-κB (p65/p50) pathway and PU.1 are closely correlated with inflammatory responses; thus, we examined the relationship and function between PU.1 and p50 in secondary spinal cord injury. In this study, we established an adult rat acute spinal cord injury model to simulate the pathological process of spinal cord injury.: We found that the expression of PU.1 was significantly increased at three days after spinal cord injury and mainly expressed in activated microglia. Moreover, p-p50 expression was increased in SCI rats and the protein interacted with PU.1. Lipopolysaccharide was used to induce microglia activation in vitro.: The results showed that PU.1 and p-p50 expression was significantly increased and PU.1 interacted with p50 in the nucleus. The levels of tumor necrosis factor-α and interleukin-1β secreted by microglia were detected by enzyme-linked immunosorbent assay. The results showed that when both PU.1 and p50 were overexpressed, tumor necrosis factor-α and interleukin-1β secretion was significantly increased to levels higher than in cells overexpressing PU.1 or p50 alone. These results suggest that PU.1 and p50 interact to promote p65 transcription and the expression of inflammatory factors, which is an important mechanism of the microglial-mediated inflammatory response to secondary injury after spinal cord injury.
继发性脊髓损伤是由活化的小胶质细胞介导的神经炎症反应对周围组织造成的炎性损伤。核因子-κB（p65/p50）信号通路与PU.1均与炎症反应密切相关；因此，我们研究了PU.1与p50在继发性脊髓损伤中的关系及作用。在本研究中，我们建立了成年大鼠急性脊髓损伤模型以模拟脊髓损伤的病理过程。我们发现，脊髓损伤后3天PU.1表达显著增加，且主要表达于活化的小胶质细胞中。此外，脊髓损伤大鼠中p-p50表达增加，且该蛋白与PU.1相互作用。体外实验中使用脂多糖诱导小胶质细胞活化。结果显示，PU.1与p-p50表达均显著增加，且PU.1在细胞核中与p50相互作用。采用酶联免疫吸附测定法检测小胶质细胞分泌的肿瘤坏死因子-α及白细胞介素-1β水平。结果显示，当PU.1与p50均过表达时，肿瘤坏死因子-α及白细胞介素-1β分泌显著增加，高于单独过表达PU.1或p50的细胞。这些结果表明，PU.1与p50相互作用以促进p65转录及炎性因子表达，这是脊髓损伤后小胶质细胞介导的继发性损伤炎症反应的重要机制。
