TRPM2 contributes to LPC-induced intracellular Ca2+ influx and microglial activation
TRPM2 contributes to LPC-induced intracellular Ca2+ influx and microglial activation
复制标题
DOI：
10.1016/j.bbrc.2017.02.087
复制
发表时间：
2017-04-01
影响因子：
3.1
通讯作者：
Oh, Seog Bae
中科院分区：
文献类型：
--
作者：
Jeong, Heejin;Kim, Yong Ho;Oh, Seog Bae
小胶质细胞是中枢神经系统(CNS)在某些病理条件下被激活的常驻免疫细胞。溶血磷脂酰胆碱(LPC)是一种内源性炎性磷脂，参与中枢神经系统神经胶质细胞的免疫调节功能。尽管已有研究发现LPC可诱导小胶质细胞内钙内流和形态改变，但仍没有直接证据表明LPC对小胶质细胞激活标志物丝裂原活化蛋白激酶(MAPK)p38(p-p38)的磷酸化有影响。此外，LPC诱导小胶质细胞激活的细胞机制尚不清楚。在这项研究中，我们发现LPC诱导原代培养的小胶质细胞内钙离子增加，而非选择性瞬时受体电位(Trp)通道阻断剂Gd3+可以阻断这一作用。RT-PCR和全细胞膜片钳记录显示Trp Melastatin 2(TRPM2)在小胶质细胞中的分子和功能表达。通过Western blotting，我们还观察到LPC增加了TRPM2基因敲除小胶质细胞中p38MAPK的磷酸化，并且p38表达的增加也被逆转。此外，LPC诱导的膜转运TRPM2和鞘内注射LPC增加了脊髓LBA-1的免疫反应性，而在KO小鼠中LBA-1的免疫反应性明显降低。此外，LPC诱导的TRPM2-KO小胶质细胞内钙升高和内向电流被取消。综上所述，我们的结果提示LPC通过TRPM2诱导细胞内钙内流，增加p38MAPK的磷酸化，进而激活小胶质细胞。(C)2017 Elsevier Inc.保留所有权利。
Microglia are the resident immune cells which become activated in some pathological conditions in central nervous system (CNS). Lysophosphatidylcholine (LPC), an endogenous inflammatory phospholipid, is implicated in immunomodulatory function of glial cells in the CNS. Although several studies uncovered that LPC induces intracellular Ca2+ influx and morphologic change in microglia, there is still no direct evidence showing change of phosphorylation of mitogen-activated protein kinase (MAPK) p38 (p-p38), a widely used microglia activation marker, by LPC. Furthermore, the cellular mechanism of LPC-induced microglia activation remains unknown. In this study, we found that LPC induced intracellular Ca2+ increase in primary cultured microglia, which was blocked in the presence of Gd3+, non-selective transient receptor potential (TRP) channel blocker. RT-PCR and whole cell patch clamp recordings revealed molecular and functional expression of TRP melastatin 2 (TRPM2) in microglia. Using western blotting, we also observed that LPC increased phosphorylation of p38 MAPK, and the increase of p-p38 expression is also reversed in TRPM2-knockout (KO) microglia. Moreover, LPC induced membrane trafficking of TRPM2 and intrathecal injection of LPC increased lba-1 immunoreactivity in the spinal cord, which were significantly reduced in KO mice. In addition, LPC-induced intracellular Ca2+ increase and inward currents were abolished in TRPM2-KO microglia. Taken together, our results suggest that LPC induces intracellular Ca2+ influx and increases phosphorylation of p38 MAPK via TRPM2, which in turn activates microglia. (C) 2017 Elsevier Inc. All rights reserved.