Abstract：
Microglial phagocytosis of myelin debris is a crucial process for promoting myelin regeneration in conditions such as multiple sclerosis (MS). Vacuolar-ATPase B2 (V-ATPase B2) has been implicated in various cellular processes, but its role in microglial phagocytosis and its potential impact on MS-related responses remain unclear. In this study, we employed BV-2 murine microglial cells to investigate the influence of V-ATPase B2 on the phagocytosis of myelin debris by microglia. The results revealed that V-ATPase B2 expression increased in response to myelin debris exposure. Overexpression of V-ATPase B2 significantly enhanced BV-2 phagocytosis of myelin debris. Additionally, V-ATPase B2 overexpression shifted microglial polarization towards an anti-inflammatory M2 phenotype, coupled with decreased lysosomal pH and enhanced lysosome degradation capacity. Moreover, endoplasmic reticulum (ER) stress inhibitor, 4-PBA, reversed the effects of V-ATPase B2 silencing on ER stress, M2 polarization, and lysosomal degradation of BV-2 cells. The MAPK pathway was inhibited upon V-ATPase B2 overexpression, contributing to heightened myelin debris clearance by BV-2 cells. Notably, MAPK pathway inhibition partially attenuated the inhibitory effects of V-ATPase B2 knockdown on myelin debris clearance. In conclusion, our findings reveal a pivotal role for V-ATPase B2 in promoting microglial phagocytosis of myelin debris by regulating microglial polarization and lysosomal function via the MAPK signaling pathway, suggesting that targeting V-ATPase B2 may hold therapeutic potential for enhancing myelin debris clearance and modulating microglial responses in MS and related neuroinflammatory disorders.
摘要：
髓鞘碎片的小胶质细胞吞噬作用是在诸如多发性硬化(MS)的病症中促进髓鞘再生的关键过程。液泡ATPaseB2（V-ATPaseB2）参与了各种细胞过程，但其在小胶质细胞吞噬作用中的作用及其对MS相关反应的潜在影响仍不清楚。在这项研究中,我们使用BV-2鼠小胶质细胞来研究V-ATPaseB2对小胶质细胞吞噬髓鞘碎片的影响。结果显示,V-ATP酶B2表达响应于髓鞘碎片暴露而增加。V-ATPaseB2的过表达显着增强了BV-2对髓鞘碎片的吞噬作用。此外,V-ATPaseB2过表达将小胶质细胞极化向抗炎M2表型转移，再加上降低溶酶体pH和增强溶酶体降解能力。此外，内质网（ER）应激抑制剂，4-PBA,逆转了V-ATPaseB2沉默对内质网应激的影响，M2极化，和BV-2细胞的溶酶体降解。V-ATPaseB2过表达后，MAPK通路受到抑制，有助于BV-2细胞清除髓鞘碎片。值得注意的是,MAPK通路抑制部分减弱了V-ATPaseB2敲低对髓磷脂碎片清除的抑制作用。总之,我们的发现揭示了V-ATPaseB2在通过MAPK信号通路调节小胶质细胞极化和溶酶体功能促进髓鞘碎片的小胶质细胞吞噬中的关键作用,提示靶向V-ATPaseB2可能具有增强MS和相关神经炎性疾病中髓磷脂碎片清除和调节小胶质细胞反应的治疗潜力.
