Increased expression of S100B and its specific receptor for advanced glycation end products (RAGE) has been described in patients with multiple sclerosis (MS), being associated with an active demyelinating process. We previously showed that a direct neutralization of S100B reduces lysophosphatidylcholine (LPC)-induced demyelination and inflammation using an ex vivo demyelinating model. However, whether S100B actions occur through RAGE and how oligodendrogenesis and remyelination are affected are not clarified. To evaluate the role of the S100B–RAGE axis in the course of a demyelinating insult, organotypic cerebellar slice cultures (OCSC) were demyelinated with LPC in the presence or absence of RAGE antagonist FPS-ZM1. Then, we explored the effects of the S100B–RAGE axis inhibition on glia reactivity and inflammation, myelination and neuronal integrity, and on oligodendrogenesis and remyelination. In the present study, we confirmed that LPC-induced demyelination increased S100B and RAGE expression, while RAGE antagonist FPS-ZM1 markedly reduced their content and altered RAGE cellular localization. Furthermore, FPS-ZM1 prevented LPC-induced microgliosis and astrogliosis, as well as NF-κB activation and pro-inflammatory cytokine gene expression. In addition, RAGE antagonist reduced LPC-induced demyelination having a beneficial effect on axonal and synaptic protein preservation. We have also observed that RAGE engagement is needed for LPC-induced oligodendrocyte (OL) maturation arrest and loss of mature myelinating OL, with these phenomena being prevented by FPS-ZM1. Our data suggest that increased levels of mature OL in the presence of FPS-ZM1 are related to increased expression of microRNAs (miRs) associated with OL differentiation and remyelination, such as miR-23a, miR-219a, and miR-338, which are defective upon LPC incubation. Finally, our electron microscopy data show that inhibition of the S100B–RAGE axis prevents axonal damage and myelin loss, in parallel with enhanced functional remyelination, as observed by the presence of thinner myelin sheaths when compared with Control. Overall, our data implicate the S100B–RAGE axis in the extent of myelin and neuronal damage, as well as in the inflammatory response that follows a demyelinating insult. Thus, prevention of RAGE engagement may represent a novel strategy for promoting not only inflammatory reduction but also neuronal and myelin preservation and/or remyelination, improving recovery in a demyelinating condition as MS.

在患有多发性硬化症（MS）的患者中，S100B及其晚期糖基化终末产物（RAGE）的特异性受体的表达增加，这与活跃的脱髓鞘过程有关。我们以前的研究表明，使用S100B直接中和S100B可减少溶血磷脂酰胆碱（LPC）引起的脱髓鞘和炎症。离体脱髓鞘模型。但是，尚不清楚S100B的作用是否通过RAGE发生，以及少突胶质细胞生成和髓鞘再生如何受到影响。为了评估S100B–RAGE轴在脱髓鞘损伤过程中的作用，在有或没有RAGE拮抗剂FPS-ZM1的情况下，用LPC使器官型小脑切片培养物（OCSC）脱髓鞘。然后，我们探索了S100B–RAGE轴抑制作用对胶质细胞反应性和炎症，髓鞘形成和神经元完整性以及少突胶质生成和髓鞘形成的影响。在本研究中，我们证实LPC诱导的脱髓鞘作用增加了S100B和RAGE的表达，而RAGE拮抗剂FPS-ZM1则明显减少了它们的含量并改变了RAGE的细胞定位。此外，FPS-ZM1预防了LPC引起的小胶质细胞增生和星形胶质细胞增生，以及NF-κB激活和促炎细胞因子基因表达。另外，RAGE拮抗剂减少了LPC诱导的脱髓鞘作用，对轴突和突触蛋白的保存具有有益作用。我们还观察到，LPC诱导的少突胶质细胞（OL）的成熟停滞和成熟髓鞘性OL的丧失需要RAGE参与，而FPS-ZM1可以防止这些现象。我们的数据表明，存在FPS-ZM1时，成熟OL的水平增加与与OL分化和髓鞘再生相关的microRNA（miR）的表达增加有关，例如miR-23a，miR-219a和miR-338， LPC孵育时有缺陷。最后，我们的电子显微镜数据显示，抑制S100B–RAGE轴可防止轴突损伤和髓磷脂损失，同时增强功能性髓鞘形成，与对照相比，有较薄的髓鞘鞘所观察到。总体而言，我们的数据表明S100B–RAGE轴涉及髓鞘和神经元损害的程度以及脱髓鞘性损伤后的炎症反应。因此，防止RAGE参与可能代表一种新的策略，不仅可以促进炎症减少，而且可以促进神经元和髓鞘的保存和/或髓鞘再生，从而改善在脱髓鞘状态下MS的恢复。