TREM2 regulates purinergic receptor-mediated calcium signaling and motility in human iPSC-derived microglia.
TREM2 regulates purinergic receptor-mediated calcium signaling and motility in human iPSC-derived microglia.
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TREM2调节人iPSC衍生的小胶质细胞中嘌呤能受体介导的钙信号传导和运动性
DOI：
10.7554/elife.73021
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发表时间：
2022-02-22
期刊：
影响因子：
7.7
通讯作者：
Cahalan MD
中科院分区：
文献类型：
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作者：
Jairaman A;McQuade A;Granzotto A;Kang YJ;Chadarevian JP;Gandhi S;Parker I;Smith I;Cho H;Sensi SL;Othy S;Blurton-Jones M;Cahalan MD
膜蛋白TREM 2（髓样细胞表达的触发受体2）调节关键的小胶质细胞功能，包括吞噬作用和趋化性。TREM 2的功能丧失变体与阿尔茨海默病（AD）风险增加相关。由于在几种AD模型中观察到Ca 2+信号传导异常，我们研究了TREM 2基因缺失的人诱导多能干细胞衍生的小胶质细胞（iPSC-小胶质细胞）中TREM 2对Ca 2+信号传导的调节。我们发现，缺乏TREM 2的iPSC-小胶质细胞（TREM 2 KO）响应于嘌呤能激动剂（例如ADP）显示出夸大的Ca 2+信号，其形成小胶质细胞损伤反应。由P2 Y12和P2 Y13受体的表达增加驱动的这种ADP超敏性导致从内质网储存中释放更多的Ca 2+，这触发通过奥赖通道的持续Ca 2+内流并改变TREM 2 KO小胶质细胞中的细胞运动性。使用表达遗传编码的Ca 2+探针Salsa 6 f的iPSC-小胶质细胞，我们发现胞质Ca 2+在TREM 2 KO小胶质细胞中更大程度地调节运动性。尽管显示出更大的整体位移，TREM 2 KO小胶质细胞表现出降低的方向趋化性沿着ADP梯度。因此，TREM 2 KO小胶质细胞中的趋化缺陷通过使用P2 Y12受体拮抗剂减少胞质Ca 2+来挽救。我们的研究结果表明，TREM 2的损失赋予的缺陷，在小胶质细胞的Ca 2+响应嘌呤能信号，这表明一个窗口的Ca 2+信号的最佳小胶质细胞运动。
The membrane protein TREM2 (Triggering Receptor Expressed on Myeloid cells 2) regulates key microglial functions including phagocytosis and chemotaxis. Loss-of-function variants of TREM2 are associated with increased risk of Alzheimer’s disease (AD). Because abnormalities in Ca2+ signaling have been observed in several AD models, we investigated TREM2 regulation of Ca2+ signaling in human induced pluripotent stem cell-derived microglia (iPSC-microglia) with genetic deletion of TREM2. We found that iPSC-microglia lacking TREM2 (TREM2 KO) show exaggerated Ca2+ signals in response to purinergic agonists, such as ADP, that shape microglial injury responses. This ADP hypersensitivity, driven by increased expression of P2Y12 and P2Y13 receptors, results in greater release of Ca2+ from the endoplasmic reticulum stores, which triggers sustained Ca2+ influx through Orai channels and alters cell motility in TREM2 KO microglia. Using iPSC-microglia expressing the genetically encoded Ca2+ probe, Salsa6f, we found that cytosolic Ca2+ tunes motility to a greater extent in TREM2 KO microglia. Despite showing greater overall displacement, TREM2 KO microglia exhibit reduced directional chemotaxis along ADP gradients. Accordingly, the chemotactic defect in TREM2 KO microglia was rescued by reducing cytosolic Ca2+ using a P2Y12 receptor antagonist. Our results show that loss of TREM2 confers a defect in microglial Ca2+ response to purinergic signals, suggesting a window of Ca2+ signaling for optimal microglial motility.