RRC ID 34814
Author Toyomitsu E, Tsuda M, Yamashita T, Tozaki-Saitoh H, Tanaka Y, Inoue K.
Title CCL2 promotes P2X4 receptor trafficking to the cell surface of microglia.
Journal Purinergic Signal.
Abstract P2X4 receptors (P2X4Rs), a subtype of the purinergic P2X family, play important roles in regulating neuronal and glial functions in the nervous system. We have previously shown that the expression of P2X4Rs is upregulated in activated microglia after peripheral nerve injury and that activation of the receptors by extracellular ATP is crucial for maintaining nerve injury-induced pain hypersensitivity. However, the regulation of P2X4R expression on the cell surface of microglia is poorly understood. Here, we identify the CC chemokine receptor CCR2 as a regulator of P2X4R trafficking to the cell surface of microglia. In a quantitative cell surface biotinylation assay, we found that applying CCL2 or CCL12, endogenous ligands for CCR2, to primary cultured microglial cells, increased the levels of P2X4R protein on the cell surface without changing total cellular expression. This effect of CCL2 was prevented by an antagonist of CCR2. Time-lapse imaging of green fluorescent protein (GFP)-tagged P2X4R in living microglial cells showed that CCL2 stimulation increased the movement of P2X4R-GFP particles. The subcellular localization of P2X4R immunofluorescence was restricted to lysosomes around the perinuclear region. Notably, CCL2 changed the distribution of lysosomes with P2X4R immunofluorescence within microglial cells and induced release of the lysosomal enzyme β-hexosaminidase, indicating lysosomal exocytosis. Moreover, CCL2-stimulated microglia enhanced Akt phosphorylation by ATP applied extracellularly, a P2X4R-mediated response. These results indicate that CCL2 promotes expression of P2X4R protein on the cell surface of microglia through exocytosis of P2X4R-containing lysosomes, which may be a possible mechanism for pain hypersensitivity after nerve injury.
Volume 8(2)
Pages 301-10
Published 2012-6
DOI 10.1007/s11302-011-9288-x
PMID 22222817
PMC PMC3350584
MeSH Animals Animals, Newborn Cell Membrane / metabolism* Cells, Cultured Chemokine CCL2 / physiology* Microglia / metabolism* Protein Transport / physiology Rats Rats, Wistar Receptors, Purinergic P2X4 / metabolism*
IF 3.19
Times Cited 38
WOS Category BIOCHEMISTRY & MOLECULAR BIOLOGY NEUROSCIENCES
Resource
DNA material pCAG-HIVgp (RDB04394) pCMV-VSV-G-RSV-Rev (RDB04393) CSII-EF-MCS (RDB04378).