Open AccessP2X7 Receptors Mediate Innate Phagocytosis by Human Neural Precursor Cells and Neuroblasts
Author(s) -
Lovelace Michael D.,
Gu Ben J.,
Eamegdool Steven S.,
Weible Michael W.,
Wiley James S.,
Allen David G.,
ChanLing Tailoi
Publication year - 2015
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1002/stem.1864
Subject(s) - neuroblast , neurogenesis , biology , phagocytosis , microbiology and biotechnology , neural stem cell , doublecortin , neun , gene knockdown , apoptosis , immunology , stem cell , neuroscience , biochemistry , dentate gyrus , immunohistochemistry , central nervous system
Abstract During early human neurogenesis there is overproduction of neuroblasts and neurons accompanied by widespread programmed cell death (PCD). While it is understood that CD68 + microglia and astrocytes mediate phagocytosis during target‐dependent PCD, little is known of the cell identity or the scavenger molecules used to remove apoptotic corpses during the earliest stages of human neurogenesis. Using a combination of multiple‐marker immunohistochemical staining, functional blocking antibodies and antagonists, we showed that human neural precursor cells (hNPCs) and neuroblasts express functional P2X7 receptors. Furthermore, using live‐cell imaging, flow cytometry, phagocytic assays, and siRNA knockdown, we showed that in a serum‐free environment, doublecortin + (DCX) neuroblasts and hNPCs can clear apoptotic cells by innate phagocytosis mediated via P2X7. We found that both P2X7 high DCX low hNPCs and P2X7 high DCX high neuroblasts, derived from primary cultures of human fetal telencephalon, phagocytosed targets including latex beads, apoptotic ReNcells, and apoptotic hNPC/neuroblasts. Pretreatment of neuroblasts and hNPCs with 1 mM adenosine triphosphate (ATP), 100 µM OxATP (P2X7 antagonist), or siRNA knockdown of P2X7 inhibited phagocytosis of these targets. Our results show that P2X7 functions as a scavenger receptor under serum‐free conditions resembling those in early neurogenesis. This is the first demonstration that hNPCs and neuroblasts may participate in clearance of apoptotic corpses during pre target‐dependent neurogenesis and mediate phagocytosis using P2X7 as a scavenger receptor. S tem C ells 2015;33:526–541