Liu Gaoxiang, Ni Jie, Mao Lei, Yan Ming, Pang Tao, Liao Hong
Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing 210009, China.
Department of Neurosurgery, Jinling Hospital, Nanjing 210000, China.
Brain Res. 2015 Nov 19;1627:41-51. doi: 10.1016/j.brainres.2015.09.006. Epub 2015 Sep 11.
As the receptor of myelin associated inhibitory factors Nogo receptor 1 (NgR1) plays an important role in central nervous system (CNS) injury and regeneration. It is found that NgR1 complex acts in neurons to transduce the signals intracelluarly including induction of growth cone collapse, inhibition of axonal regeneration and regulation of nerve inflammation. In recent studies, NgR1 has also been found to be expressed in the microglia. However, NgR1 expressed in microglia in the developing nervous systems and following CNS injury have not been widely investigated. In this study, we detected the expression and cellular localization of NgR1 in microglia during development and following traumatic brain injury (TBI) in mice. The results showed that NgR1 was mainly expressed in microglia during embryonic and postnatal periods. The expression levels peaked at P4 and decreased thereafter into adulthood, while increased significantly with aging representatively at 17 mo. On the other hand, there was no significant difference in the number of double positive NgR1(+)Iba1(+) cells between normal and TBI group. In summary, we first detected the expression of NgR1 in microglia during development and found that NgR1 protein expression increased significantly in microglia with aging. These findings will contribute to make a foundation for subsequent study about the role of NgR1 expressed in microglia on the CNS disorders.
作为髓磷脂相关抑制因子的受体，Nogo受体1（NgR1）在中枢神经系统（CNS）损伤和再生中发挥着重要作用。研究发现，NgR1复合物在神经元中起作用，在细胞内转导信号，包括诱导生长锥塌陷、抑制轴突再生和调节神经炎症。在最近的研究中，还发现NgR1在小胶质细胞中表达。然而，在发育中的神经系统和中枢神经系统损伤后小胶质细胞中表达的NgR1尚未得到广泛研究。在本研究中，我们检测了小鼠发育过程中和创伤性脑损伤（TBI）后小胶质细胞中NgR1的表达和细胞定位。结果表明，NgR1在胚胎期和出生后主要在小胶质细胞中表达。表达水平在出生后第4天达到峰值，此后下降至成年期，而在17个月时随着年龄增长显著增加。另一方面，正常组和TBI组之间双阳性NgR1(+)Iba1(+)细胞数量没有显著差异。总之，我们首次检测了发育过程中小胶质细胞中NgR1的表达，发现随着年龄增长，小胶质细胞中NgR1蛋白表达显著增加。这些发现将为后续研究小胶质细胞中表达的NgR1对中枢神经系统疾病的作用奠定基础。
