Wang Yuan, Wang Mengyang, Zhang Xiumin, Luo Ming
Department of Neurosurgery, Wuhan NO.1 Hospital, Wuhan 432000, China.
Department of Neurosurgery, Wuhan NO.1 Hospital, Wuhan 432000, China. *Corresponding author, E-mail:
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi. 2025 Jan;41(1):31-37.
Objective To investigate the effects and molecular mechanism of Homer protein homolog 1a (Homer 1a) overexpression on nerve injury in mice with traumatic brain injury (TBI). Methods Sixty male C57BL/6 mice were randomly divided into five groups: sham group, TBI group, empty lentivirus (Lv-NC) group, Homer 1a overexpression lentivirus (Lv-Homer 1a) group and Lv-Homer 1a + 740 Y-P group, with 12 mice in each group. The lentivirus was orthotopic injected into the cerebral cortex of mice 5 d before modeling, while 740 Y-P was injected intraperitoneally 1 d before modeling. The TBI model was established using the free-fall impact method, and the modified neurological severity scores (mNSS) of the mice was assessed 72 h post-surgery. The water content of brain tissue was quantified, and the histopathological damage and neuronal loss in brain tissue were assessed using HE staining and Nissl staining respectively. The formation of autophagosomes in brain tissue was observed by transmission electron microscopy. The protein expression levels of Homer 1a, microtubule-associated protein 1 light chain 3B (LC3B), Beclin 1, phosphatidylinositol 3-kinase (PI3K), phosphorylation PI3K(p-PI3K), protein kinase B (AKT), p-AKT, mammalian target of rapamycin (mTOR), and p-mTOR in brain tissue were detected by Western blot analysis. Results Compared to the sham group, the mice in the TBI group exhibited a significant increase in mNSS and cerebral water content. Moreover, severe brain tissue pathological damage was observed, accompanied by a substantial loss of neurons and an increase in autophagosome formation. The protein expressions of Homer 1a and Beclin 1, as well as the protein ratio of LC3B-II/LC3B-I, in brain tissues were significantly elevated, while the protein ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR were significantly reduced. Compared to the TBI group, the Lv-Homer 1a group exhibited reduced mNSS and brain water content. Additionally, there was an improvement in pathological brain tissue damage and neuron loss. Furthermore, there was an increase in autophagosome formation and expression of autophagy-related proteins, while the protein ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR were decreased. Compared to the Lv-Homer 1a group, the nerve injury in the Lv-Homer 1a+740 Y-P group was exacerbated, accompanied by a reduction in autophagosome formation and expression of autophagy-related proteins, while the PI3K/AKT/mTOR signaling pathway was activated. Conclusion Overexpression of Homer 1a effectively mitigates neurological damage in TBI mice, potentially through modulation of autophagy mediated by the PI3K/AKT/mTOR signaling pathway.
目的 探讨同源蛋白1a（Homer 1a）过表达对创伤性脑损伤（TBI）小鼠神经损伤的影响及其分子机制。方法 将60只雄性C57BL/6小鼠随机分为五组：假手术组、TBI组、空载体慢病毒（Lv-NC）组、Homer 1a过表达慢病毒（Lv-Homer 1a）组和Lv-Homer 1a + 740 Y-P组，每组12只。建模前5天将慢病毒原位注射到小鼠大脑皮层，建模前1天腹腔注射740 Y-P。采用自由落体撞击法建立TBI模型，术后72小时评估小鼠的改良神经功能缺损评分（mNSS）。定量脑组织含水量，分别采用HE染色和尼氏染色评估脑组织的组织病理学损伤和神经元丢失情况。通过透射电子显微镜观察脑组织中自噬体的形成。采用蛋白质免疫印迹法检测脑组织中Homer 1a、微管相关蛋白1轻链3B（LC3B）、Beclin 1、磷脂酰肌醇3激酶（PI3K）、磷酸化PI3K（p-PI3K）、蛋白激酶B（AKT）、p-AKT、哺乳动物雷帕霉素靶蛋白（mTOR）和p-mTOR的蛋白表达水平。结果 与假手术组相比，TBI组小鼠的mNSS和脑含水量显著增加。此外，观察到严重的脑组织病理损伤，伴有大量神经元丢失和自噬体形成增加。脑组织中Homer 1a和Beclin 1的蛋白表达以及LC3B-II/LC3B-I的蛋白比值显著升高，而p-PI3K/PI3K、p-AKT/AKT和p-mTOR/mTOR的蛋白比值显著降低。与TBI组相比，Lv-Homer 1a组小鼠的mNSS和脑含水量降低。此外，脑组织病理损伤和神经元丢失有所改善。此外，自噬体形成和自噬相关蛋白的表达增加，而p-PI3K/PI3K、p-AKT/AKT和p-mTOR/mTOR的蛋白比值降低。与Lv-Homer 组相比，Lv-Homer 1a + 74 Y-P组的神经损伤加重，伴有自噬体形成和自噬相关蛋白表达减少，而PI3K/AKT/mTOR信号通路被激活。结论 Homer 1a过表达可有效减轻TBI小鼠的神经损伤，可能是通过调节PI3K/AKT/mTOR信号通路介导的自噬实现的。
