PDF(Pubmed)
Abstract：
Autoantibodies directed against the N-methyl-D-aspartate receptor (NMDAR-Ab) are pathogenic immunoglobulins detected in patients suffering from NMDAR encephalitis. NMDAR-Ab alter the receptor membrane trafficking, synaptic transmission and neuronal network properties, leading to neurological and psychiatric symptoms in patients. Patients often have very little neuronal damage but rapid and massive (treatment-responsive) brain dysfunctions related to an unknown early mechanism of NMDAR-Ab. Our understanding of this early molecular cascade remains surprisingly fragmented. Here, we used a combination of single molecule-based imaging of membrane proteins to unveil the spatiotemporal action of NMDAR-Ab on live hippocampal neurons. We first demonstrate that different clones of NMDAR-Ab primarily affect extrasynaptic (and not synaptic) NMDARs. In the first minutes, NMDAR-Ab increase extrasynaptic NMDAR membrane dynamics, declustering its surface interactome. NMDAR-Ab also rapidly reshuffle all membrane proteins located in the extrasynaptic compartment. Consistent with this alteration of multiple proteins, effects of NMDAR-Ab were not mediated through the sole interaction between the NMDAR and EphB2 receptor. In the long term, NMDAR-Ab reduce the NMDAR synaptic pool by slowing down receptor membrane dynamics in a cross-linking-independent manner. Remarkably, exposing only extrasynaptic NMDARs to NMDAR-Ab was sufficient to produce their full-blown effect on synaptic receptors. Collectively, we demonstrate that NMDAR-Ab initially impair extrasynaptic proteins, then the synaptic ones. These data thus shed new and unsuspected light on the mode of action of NMDAR-Ab and, probably, our understanding of (extra)synaptopathies.
摘要：
针对N-甲基-D-天冬氨酸受体(NMDAR-Ab)的自身抗体是在患有NMDAR脑炎的患者中检测到的致病性免疫球蛋白。NMDAR-Ab改变受体膜运输，突触传递和神经元网络特性，导致患者出现神经和精神症状。患者通常具有非常少的神经元损伤,但是与NMDAR-Ab的未知早期机制相关的快速和大量(治疗响应性)脑功能障碍。我们对这种早期分子级联的理解仍然令人惊讶地支离破碎。这里,我们使用了基于单分子的膜蛋白成像组合,以揭示NMDAR-Ab对活海马神经元的时空作用.我们首先证明了NMDAR-Ab的不同克隆主要影响突触外-而不是突触-NMDAR。在第一分钟,NMDAR-Ab增加突触外NMDAR膜动力学，对其表面相互作用组进行去聚类。NMDAR-Ab还快速重组位于突触外室的所有膜蛋白。与多种蛋白质的这种改变一致，NMDAR-Ab效应不是通过NMDAR和EphB2受体之间的唯一相互作用介导的。从长远来看，NMDAR-Ab通过以交联独立的方式减慢受体膜动力学来减少NMDAR突触池。值得注意的是,仅将突触外NMDAR暴露于NMDAR-Ab就足以对突触受体产生全面影响。总的来说，我们证明NMDAR-Ab首先损害突触外蛋白，然后是突触。这些数据如此新，没有怀疑，点亮NMDAR-Ab的作用模式，并可能有助于我们对(额外)突触病理学的理解。
