Specific binding of collagen Q to the neuromuscular junction is exploited to cure congenital myasthenia and to explore bases of myasthenia gravis.
Specific binding of collagen Q to the neuromuscular junction is exploited to cure congenital myasthenia and to explore bases of myasthenia gravis.
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DOI：
10.1016/j.cbi.2012.08.020
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发表时间：
2013-03-25
影响因子：
5.1
通讯作者：
Engel, Andrew G.
中科院分区：
文献类型：
--
作者：
Ohno, Kinji;Ito, Mikako;Kawakami, Yu;Krejci, Eric;Engel, Andrew G.
神经肌肉接头 (NMJ) 处的乙酰胆碱酯酶 (AChE) 通过不对称 AChE (AChE/ColQ) 形式的三螺旋胶原蛋白 Q (ColQ) 锚定到突触基底层。 ColQ 的 C 端结构域与 MuSK（肌肉特异性受体酪氨酸激酶）结合，介导 NMJ 处乙酰胆碱受体 (AChR) 聚集的信号。 ColQ 还与硫酸乙酰肝素蛋白聚糖（包括基底膜聚糖）结合。 ColQ 先天性缺陷导致终板 AChE 缺陷。对 Colq−/− 小鼠单次静脉注射腺相关病毒血清型 8 (AAV8)-COLQ 可恢复运动功能、突触传递和 NMJ 超微结构。我们还将 AAV1-COLQ-IRES-EGFP 注射到左胫骨前肌，并观察到 AChE/ColQ 在所有检查的非注射肢体 NMJ 上的共定位。此外，将纯化的重组AChE/ColQ蛋白复合物注射到臀大肌中，未注射的前肢中积累了AChE。这些观察结果表明，可以利用 ColQ 的组织靶向信号将转基因产物特异性递送至靶组织。 MuSK 抗体阳性重症肌无力 (MG) 占自身免疫性 MG 的 5-15%。由于 AChR 缺乏通常是轻微的，并且胆碱酯酶抑制剂通常无效或加重肌无力症状，因此我们询问患者的 MuSK-IgG 是否干扰 ColQ 与 MuSK 的结合。在体外将 AChE/ColQ 覆盖到 Colq−/− 小鼠的肌肉切片上表明 MuSK-IgG 阻断 ColQ 与 NMJ 的结合。 MuSK 与 ColQ 的体外板结合表明 MuSK-IgG 对 MuSK-ColQ 相互作用产生剂量依赖性阻断。此外，将 MuSK-IgG 被动转移至小鼠体内，可使 ColQ 的大小和密度减少至对照的 10% 左右，并且对 AChR 和 MuSK 的大小和密度影响较小。阐明 ColQ 与 NMJ 特异性结合的分子机制使我们能够改善 Colq−/− 小鼠的毁灭性肌无力症状，并揭示抗 MuSK MG 的基础。
Acetylcholinesterase (AChE) at the neuromuscular junction (NMJ) is anchored to the synaptic basal lamina via a triple helical collagen Q (ColQ) in the form of asymmetric AChE (AChE/ColQ). The C-terminal domain of ColQ binds to MuSK, the muscle-specific receptor tyrosine kinase, that mediates a signal for acetylcholine receptor (AChR) clustering at the NMJ. ColQ also binds to heparan sulfate proteoglycans including perlecan. Congenital defects of ColQ cause endplate AChE deficiency. A single intravenous administration of adeno-associated virus serotype 8 (AAV8)-COLQ to Colq−/− mice rescued motor functions, synaptic transmission, and the ultrastructure of NMJ. We also injected AAV1-COLQ-IRES-EGFP to the left tibialis anterior and observed colocalization of AChE/ColQ at all the examined NMJs of the non-injected limbs. Additionally, injection of purified recombinant AChE/ColQ protein complex into gluteus maximus accumulated AChE in non-injected forelimbs. These observations suggest that the tissue-targeting signal of ColQ can be exploited to specifically deliver the transgene product to the target tissue. MuSK antibody-positive myasthenia gravis (MG) accounts for 5–15% of autoimmune MG. As AChR deficiency is typically mild and as cholinesterase inhibitors are generally ineffective or worsen myasthenic symptoms, we asked if the patient's MuSK-IgG interferes with binding of ColQ to MuSK. In vitro overlay of AChE/ColQ to muscle sections of Colq−/− mice revealed that MuSK-IgG blocks binding of ColQ to the NMJ. In vitro plate-binding of MuSK to ColQ disclosed that MuSK-IgG exerts a dose-dependent block of MuSK-ColQ interaction. In addition, passive transfer of MuSK-IgG to mice reduced the size and density of ColQ to ~10% of controls and had a lesser effect on the sizes and densities of AChR and MuSK. Elucidation of molecular mechanisms of specific binding of ColQ to the NMJ enabled us to ameliorate devastating myasthenic symptoms of Colq−/− mice and to reveal bases of anti-MuSK MG.
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影响因子：
7.8
作者：
Feng, G;Krejci, E;Molgo, J;Cunningham, J M;Massoulie, J;Sanes, J R
通讯作者：
Sanes, J R
影响因子：
5.1
作者：
Riviere, C.;Danos, O.;Douar, A. M.
通讯作者：
Douar, A. M.
DOI：
10.1083/jcb.145.4.911
发表时间：
1999-05-17
期刊：
The Journal of cell biology
影响因子：
--
作者：
Peng HB;Xie H;Rossi SG;Rotundo RL
通讯作者：
Rotundo RL
DOI：
10.1073/pnas.95.16.9654
发表时间：
1998-08-04
影响因子：
11.1
作者：
Ohno, K;Brengman, J;Engel, AG
通讯作者：
Engel, AG
影响因子：
14.5
作者：
Farrugia, Maria Elena;Robson, Matthew D.;Vincent, Angela
通讯作者：
Vincent, Angela