Karamita Maria, Barnum Christopher, Möbius Wiebke, Tansey Malú G, Szymkowski David E, Lassmann Hans, Probert Lesley
Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, Greece.
Department of Physiology, Emory University, Atlanta, Georgia, USA.
JCI Insight. 2017 Apr 20;2(8). doi: 10.1172/jci.insight.87455.
Multiple sclerosis (MS) is an inflammatory CNS demyelinating disease in which remyelination largely fails. Transmembrane TNF (tmTNF) and TNF receptor 2 are important for remyelination in experimental MS models, but it is unknown whether soluble TNF (solTNF), a major proinflammatory factor, is involved in regeneration processes. Here, we investigated the specific contribution of solTNF to demyelination and remyelination in the cuprizone model. Treatment with XPro1595, a selective inhibitor of solTNF that crosses the intact blood-brain barrier (BBB), in cuprizone-fed mice did not prevent toxin-induced oligodendrocyte loss and demyelination, but it permitted profound early remyelination due to improved phagocytosis of myelin debris by CNS macrophages and prevented disease-associated decline in motor performance. The beneficial effects of XPro1595 were absent in TNF-deficient mice and replicated in tmTNF-knockin mice, showing that tmTNF is sufficient for the maintenance of myelin and neuroprotection. These findings demonstrate that solTNF inhibits remyelination and repair in a cuprizone demyelination model and suggest that local production of solTNF in the CNS might be one reason why remyelination fails in MS. These findings also suggest that disinhibition of remyelination by selective inhibitors of solTNF that cross the BBB might represent a promising approach for treatment in progressive MS.
多发性硬化症(MS)是一种中枢神经系统炎症性脱髓鞘疾病,在这种疾病中髓鞘再生大多失败。跨膜TNF(tmTNF)和TNF受体2对实验性MS模型中的髓鞘再生很重要,但尚不清楚主要促炎因子可溶性TNF(solTNF)是否参与再生过程。在此,我们研究了solTNF在铜螯合剂模型中对脱髓鞘和髓鞘再生的具体作用。在喂食铜螯合剂的小鼠中,用可穿过完整血脑屏障(BBB)的solTNF选择性抑制剂XPro1595进行治疗,并未阻止毒素诱导的少突胶质细胞丢失和脱髓鞘,但由于中枢神经系统巨噬细胞对髓鞘碎片的吞噬作用改善,它允许早期进行深度髓鞘再生,并防止了与疾病相关的运动功能下降。在TNF缺陷小鼠中未观察到XPro1595的有益作用,而在tmTNF基因敲入小鼠中则重现了该作用,表明tmTNF足以维持髓鞘和神经保护作用。这些发现表明,solTNF在铜螯合剂脱髓鞘模型中抑制髓鞘再生和修复,并提示中枢神经系统中solTNF的局部产生可能是MS中髓鞘再生失败的原因之一。这些发现还表明,可穿过血脑屏障的solTNF选择性抑制剂对髓鞘再生的去抑制作用可能是进行性MS治疗中一种有前景的方法。