Plaque associated microglia hyper-secrete extracellular vesicles and accelerate tau propagation in a humanized APP mouse model.
Plaque associated microglia hyper-secrete extracellular vesicles and accelerate tau propagation in a humanized APP mouse model.
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DOI：
10.1186/s13024-021-00440-9
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发表时间：
2021-03-22
影响因子：
15.1
通讯作者：
Ikezu T
中科院分区：
文献类型：
--
作者：
Clayton K;Delpech JC;Herron S;Iwahara N;Ericsson M;Saito T;Saido TC;Ikezu S;Ikezu T
最近的研究表明，小胶质细胞有助于阿尔茨海默病的tau病理进展。淀粉样斑块的积累将小胶质细胞（大脑中的原发性先天免疫细胞）转化为神经退行性小胶质细胞（MGnD），其表现出对斑块、凋亡神经元和含有聚集和磷酸化tau （p-tau）的营养不良神经突的增强吞噬。目前尚不清楚小胶质细胞如何在积极吞噬病理蛋白的同时促进疾病进展，从而改善病理。将表达P301L tau突变体的腺相关病毒（AAV-P301L-tau）立体定向注射到C57BL/6 （WT）和人源化APP突变敲入纯合子（AppNL-G-F）小鼠的内侧内鼻皮层（MEC）中。从4到6个月大的小鼠分别喂食含有集落刺激因子-1受体抑制剂（PLX5622）的食物或对照食物，以测试小胶质细胞消耗的效果。动物在6月龄时进行免疫荧光、生化和小胶质细胞的FACS检测。为了在体内监测小胶质细胞外囊泡分泌，设计了一种新的慢病毒EV报告系统，在小胶质细胞中特异性表达mE-CD9，并将其注射到MEC的同一区域。MEC中表达P301L tau突变体诱导tau向海马齿状回颗粒细胞层增殖，与WT对照小鼠相比，AppNL-G-F小鼠的tau向齿状回颗粒细胞层增殖明显加剧。虽然PLX5622增加了斑块负担和斑块相关的p-tau+营养不良神经突，但它几乎耗尽了小鼠大脑中所有的小胶质细胞，并显著减少了WT和AppNL-G-F小鼠中p-tau的增殖。斑块相关的MGnD小胶质细胞强烈表达EV标记物，肿瘤易感基因101，表明EV合成增加。皮质内注射mE-CD9慢病毒成功诱导了mE-CD9+ EV颗粒的小胶质细胞特异性表达，与Mac2 -稳态小胶质细胞相比，Mac2+ MGnD小胶质细胞中mE-CD9+ EV颗粒的表达显著增强。最后，在AppNL-G-F小鼠皮层内连续注射mE-CD9慢病毒和AAV-P301L-tau，通过超分辨显微镜和免疫电镜观察，发现小胶质细胞特异性mE-CD9+ ev中p-tau被包封。我们的研究结果表明，MGnD小胶质细胞在压实a β斑块和清除NP tau的同时超分泌p-tau+ ev，我们认为这是AppNL-G-F小鼠淀粉样斑块沉积和tau增殖加剧之间的一种新的机制联系。在线版本包含补充材料，可在10.1186/s13024-021-00440-9获得。
Recent studies suggest that microglia contribute to tau pathology progression in Alzheimer’s disease. Amyloid plaque accumulation transforms microglia, the primary innate immune cells in the brain, into neurodegenerative microglia (MGnD), which exhibit enhanced phagocytosis of plaques, apoptotic neurons and dystrophic neurites containing aggregated and phosphorylated tau (p-tau). It remains unclear how microglia promote disease progression while actively phagocytosing pathological proteins, therefore ameliorating pathology. Adeno-associated virus expressing P301L tau mutant (AAV-P301L-tau) was stereotaxically injected into the medial entorhinal cortex (MEC) in C57BL/6 (WT) and humanized APP mutant knock-in homozygote (AppNL-G-F) mice at 5 months of age. Mice were fed either chow containing a colony stimulating factor-1 receptor inhibitor (PLX5622) or control chow from 4 to 6 months of age to test the effect of microglia depletion. Animals were tested at 6 months of age for immunofluorescence, biochemistry, and FACS of microglia. In order to monitor microglial extracellular vesicle secretion in vivo, a novel lentiviral EV reporter system was engineered to express mEmerald-CD9 (mE-CD9) specifically in microglia, which was injected into the same region of MEC. Expressing P301L tau mutant in the MEC induced tau propagation to the granule cell layer of the hippocampal dentate gyrus, which was significantly exacerbated in AppNL-G-F mice compared to WT control mice. Administration of PLX5622 depleted nearly all microglia in mouse brains and dramatically reduced propagation of p-tau in WT and to a greater extent in AppNL-G-F mice, although it increased plaque burden and plaque-associated p-tau+ dystrophic neurites. Plaque-associated MGnD microglia strongly expressed an EV marker, tumor susceptibility gene 101, indicative of heightened synthesis of EVs. Intracortical injection of mE-CD9 lentivirus successfully induced microglia-specific expression of mE-CD9+ EV particles, which were significantly enhanced in Mac2+ MGnD microglia compared to Mac2− homeostatic microglia. Finally, consecutive intracortical injection of mE-CD9 lentivirus and AAV-P301L-tau into AppNL-G-F mice revealed encapsulation of p-tau in microglia-specific mE-CD9+ EVs as determined by super-resolution microscopy and immuno-electron microscopy. Our findings suggest that MGnD microglia hyper-secrete p-tau+ EVs while compacting Aβ plaques and clearing NP tau, which we propose as a novel mechanistic link between amyloid plaque deposition and exacerbation of tau propagation in AppNL-G-F mice. The online version contains supplementary material available at 10.1186/s13024-021-00440-9.
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影响因子：
4.3
作者：
DeVos SL;Corjuc BT;Oakley DH;Nobuhara CK;Bannon RN;Chase A;Commins C;Gonzalez JA;Dooley PM;Frosch MP;Hyman BT
通讯作者：
Hyman BT
影响因子：
5.1
作者：
Fu, Ruying;Shen, Qingyu;Xu, Pengfei;Luo, Jin Jun;Tang, Yamei
通讯作者：
Tang, Yamei
影响因子：
3.4
作者：
Hanslik KL;Ulland TK
通讯作者：
Ulland TK
影响因子：
11.2
作者：
Butovsky, Oleg;Jedrychowski, Mark P.;Cialic, Ron;Krasemann, Susanne;Murugaiyan, Gopal;Fanek, Zain;Greco, David J.;Wu, Pauline M.;Doykan, Camille E.;Kiner, Olga;Lawson, Robert J.;Frosch, Matthew P.;Pochet, Nathalie;El Fatimy, Rachid;Krichevsky, Anna M.;Gygi, Steven P.;Lassmann, Hans;Berry, James;Cudkowicz, Merit E.;Weiner, Howard L.
通讯作者：
Weiner, Howard L.
影响因子：
8.3
作者：
Ito, D;Tanaka, K;Fukuuchi, Y
通讯作者：
Fukuuchi, Y