Department of Pharmacology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China.
Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China.
Biochem Pharmacol. 2018 Sep;155:110-123. doi: 10.1016/j.bcp.2018.06.028. Epub 2018 Jun 23.
Sulfasalazine (SF) promotes remyelination and improves the outcome of multiple sclerosis (MS) patients. However, the underlining mechanism remains elusive. Here, we examined whether SF blocks microglia switching to a pro-inflammatory M1-like phenotype through a competing endogenous RNA (ceRNA) effects in cuprizone-induced demyelination. The microglia reprogramming effects of SF in the mice model of cuprizone-induced demyelination was measured by histological, immunohistochemical and molecular biological methods. We also measured the effects of the condition media from SF-treated microglia on the differentiation of OLN-93 cells. Insights of the mechanism of ceRNAs of miR-136-5p and long non-coding RNA (lncRNA) HOTAIR were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation. Microglia switched to a pro-inflammatory M1-like phenotype in cuprizone induced-demyelination. Conversely, SF inhibited the M1-like polarization with the increased remyelination which was attenuated by microglia depletion. SF inhibited production of M1-like factors TNF-α and INF-γ in microglia, and thereby promoted the differentiation of OLN-93 oligodendrocytes. SF down-regulated lncRNA HOTAIR but up-regulated miR-136-5p, and thus inactivated AKT2-NF-κB in cuprizone-treated microglia. Importantly, lncRNA HOTAIR overexpression reversed the increased miR-136-5p expression by SF and thereby attenuated the inhibition of AKT2-mediated NF-κB activation. Mimic of miR-136-5p inhibited cuprizone-induced activation of AKT2-NF-κB in the microglia. In summary, SF blocks microglia switching to a pro-inflammatory M1-like phenotype by ceRNA effect of miR-136-5p and lncRNA HOTAIR in cuprizone-induced demyelination. Our findings show the therapeutic potential of SF for human MS probably by targeting epigenetic regulation in microglia.
柳氮磺胺吡啶（SF）可促进髓鞘再生，改善多发性硬化症（MS）患者的预后。然而，其潜在机制尚不清楚。本研究旨在探讨 SF 是否通过竞争性内源性 RNA（ceRNA）在铜诱导脱髓鞘中的作用来阻止小胶质细胞向促炎 M1 样表型的转变。通过组织学、免疫组织化学和分子生物学方法检测 SF 在铜诱导脱髓鞘小鼠模型中小胶质细胞重编程的作用。我们还测量了 SF 处理的小胶质细胞条件培养基对 OLN-93 细胞分化的影响。通过生物信息学分析、荧光素酶测定和 RNA 结合蛋白免疫沉淀获得了 miR-136-5p 和长链非编码 RNA（lncRNA）HOTAIR 的 ceRNA 机制的见解。小胶质细胞在铜诱导脱髓鞘中向促炎 M1 样表型转变。相反，SF 抑制 M1 样极化，促进髓鞘再生，而小胶质细胞耗竭则减弱这种作用。SF 抑制小胶质细胞中 M1 样因子 TNF-α和 INF-γ的产生，并促进 OLN-93 少突胶质细胞的分化。SF 下调 lncRNA HOTAIR 但上调 miR-136-5p，从而使铜处理小胶质细胞中的 AKT2-NF-κB 失活。重要的是，lncRNA HOTAIR 的过表达逆转了 SF 引起的 miR-136-5p 表达增加，并由此减弱了 AKT2 介导的 NF-κB 激活的抑制作用。miR-136-5p 的模拟物抑制了铜诱导的小胶质细胞中 AKT2-NF-κB 的激活。总之，SF 通过 ceRNA 效应阻断 miR-136-5p 和 lncRNA HOTAIR 在铜诱导脱髓鞘中小胶质细胞向促炎 M1 样表型的转变。我们的研究结果表明，SF 通过针对小胶质细胞中的表观遗传调控，为人类 MS 提供了治疗潜力。
