Qin Jian, He Ye, Yu Weiyi, Zhang Zhaoyong, Chen Xiaodan, Hu Yafang, Jiang Haishan
Nanfang Hospital, Southern Medical University, No.1023, South Shatai Road, Baiyun District, Guangzhou, Guangdong, China.
Nanfang Hospital, Southern Medical University, No.1023, South Shatai Road, Baiyun District, Guangzhou, Guangdong, China; Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, Guangdong, China.
Arch Biochem Biophys. 2025 Sep;771:110499. doi: 10.1016/j.abb.2025.110499. Epub 2025 Jun 5.
Amyotrophic lateral sclerosis (ALS) is a progressive fatal neurodegenerative disease characterized by severe dysfunction in upper and lower motor neurons. Previous studies have reported that the optineurin gene (OPTN) downregulation is one of the causative genetic factors for ALS, leading to the dysfunction of optineurin (OPTN), a multifunctional protein implicated in several cellular processes. Herein, we found that conditional knockout of the Optn gene in mouse microglia leads to activation of microglia. In subsequent studies, we also found that OPTN knockdown in BV2 cells leads to the activation of BV2 cells and promotes the apoptosis of co-cultured NSC34 cells via exosomes derived from BV2 cells in vitro. In contrast, OPTN knockdown in NSC34 cells did not cause apoptosis of the NSC34 cells themselves. It was suggested that microglia activation is involved in ALS initiation and development, but the nature of microglial-neuronal interactions remained elusive, requiring further exploration. Exosomes have been proven to be essential mediators. Notably, increased miRNA-125b-5p expression was uncovered in BV2 cells with the OPTN gene silenced, their derived exosomes, as well as the cocultured NSC34 cells. Interestingly, we proved that increased miRNA-125b-5p enhanced the apoptosis of NSC34 cells. We further noted that the overexpression of miRNA-125b-5p in BV2 cells can be regulated by an NF-κB activator (LPS) or inhibitor (withaferin A). Altogether, this study showed that silencing the OPTN gene may overexpress miRNA-125b-5p levels via the classical NF-κB pathway in BV2 cells. Up-regulated miRNA-125b-5p might be transmitted from exosomes to NSC34 cells, resulting in NSC34 cells apoptosis. Microglial-neuronal interactions mediated by exosomes were the crucial mechanism of OPTN gene downregulation leading to ALS, and this conclusion had been verified in cell models.
肌萎缩侧索硬化症（ALS）是一种进行性致命性神经退行性疾病，其特征是上下运动神经元严重功能障碍。先前的研究报道，视紫质神经元基因（OPTN）下调是ALS的致病遗传因素之一，导致视紫质神经元（OPTN）功能障碍，OPTN是一种参与多种细胞过程的多功能蛋白质。在此，我们发现小鼠小胶质细胞中Optn基因的条件性敲除会导致小胶质细胞活化。在后续研究中，我们还发现BV2细胞中OPTN基因敲低会导致BV2细胞活化，并通过体外BV2细胞衍生的外泌体促进共培养的NSC34细胞凋亡。相比之下，NSC34细胞中OPTN基因敲低并未导致NSC34细胞自身凋亡。提示小胶质细胞活化参与ALS的发生发展，但小胶质细胞与神经元相互作用的本质仍不清楚，需要进一步探索。外泌体已被证明是重要的介质。值得注意的是，在OPTN基因沉默的BV2细胞、其衍生的外泌体以及共培养的NSC34细胞中，发现miRNA-125b-5p表达增加。有趣的是，我们证明增加的miRNA-125b-5p会增强NSC34细胞的凋亡。我们进一步注意到，BV2细胞中miRNA-125b-5p的过表达可由NF-κB激活剂（脂多糖）或抑制剂（白屈菜红碱）调节。总之，本研究表明，沉默OPTN基因可能通过经典的NF-κB途径在BV2细胞中使miRNA-125b-5p水平过表达。上调的miRNA-125b-5p可能从外泌体传递到NSC34细胞，导致NSC34细胞凋亡。外泌体介导的小胶质细胞与神经元相互作用是OPTN基因下调导致ALS的关键机制，这一结论已在细胞模型中得到验证。
