Activation of microglial P2Y12 receptor is required for outward potassium currents in response to neuronal injury

• Type of Material: Article
• Authors: Przemyslaw Swiatkowski, Rutgers University; Madhuvika Murugan, Rutgers University; Ukpong B. Eyo, Rutgers University; Yuanyin Wang, Anhui Medical University; Srikant Rangaraju, Emory University; Seog Bae Oh, Seoul National University; Long-Jun Wu, Rutgers University
• Language: English
• Date: 2016-03-24
• Publisher: PERGAMON-ELSEVIER SCIENCE LTD
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016 IBRO.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.neuroscience.2016.01.008
• Title of Journal or Parent Work: Neuroscience
• Volume: 318
• Start Page: 22
• End Page: 33
• Grant/Funding Information: This work is supported by National Institute of Health (R01NS088627, T32GM8339, T32ES007148), New Jersey Commission on Spinal Cord Research (CSCR15ERG015), National Natural Science Foundation of China (81271162), and Korean National Research Foundation grant (2012R1A3A2048834).
• Keywords: SPINAL MICROGLIA; NEUROPATHIC PAIN; BRAIN-SLICES; microglia; IN-VIVO; OPERATED CALCIUM-ENTRY; EXTRACELLULAR ATP; P2Y12 receptor; Neurosciences & Neurology; Neurosciences; P2Y(12) RECEPTOR; STATUS EPILEPTICUS; Life Sciences & Biomedicine; ADENYLYL-CYCLASE; K+ channels; PROCESS EXTENSION; ATP; Science & Technology
• Research Categories: Biology, Cell; Biology, Neuroscience

Abstract

Microglia, the resident immune cells in the central nervous system (CNS), constantly survey the surrounding neural parenchyma and promptly respond to brain injury. Activation of purinergic receptors such as P2Y12 receptors (P2Y12R) in microglia has been implicated in chemotaxis toward ATP that is released by injured neurons and astrocytes. Activation of microglial P2Y12R elicits outward potassium current that is associated with microglial chemotaxis in response to injury. This study aimed at investigating the identity of the potassium channel implicated in microglial P2Y12R-mediated chemotaxis following neuronal injury and understanding the purinergic signaling pathway coupled to the channel. Using a combination of two-photon imaging, electrophysiology and genetic tools, we found the ATP-induced outward current to be largely dependent on P2Y12R activation and mediated by G-proteins. Similarly, P2Y12R-coupled outward current was also evoked in response to laser-induced single neuron injury. This current was abolished in microglia obtained from mice lacking P2Y12R. Dissecting the properties of the P2Y12R-mediated current using a pharmacological approach revealed that both the ATP and neuronal injury-induced outward current in microglia was sensitive to quinine (1 mM) and bupivacaine (400 μM), but not tetraethylammonium (TEA) (10 mM) and 4-aminopyridine (4-AP) (5 mM). These results suggest that the quinine/bupivacaine-sensitive potassium channels are the functional effectors of the P2Y12R-mediated signaling in microglia activation following neuronal injury.