TRPM2 is elevated in the tMCAO stroke model, transcriptionally regulated, and functionally expressed in C13 microglia.
We report the detailed expression profile of TRPM2 mRNA within the human central nervous system (CNS) and demonstrate increased TRPM2 mRNA expression at 1 and 4 weeks following ischemic injury in the rat transient middle cerebral artery occlusion (tMCAO) stroke model. Microglial cells play a key role in pathology produced following ischemic injury in the CNS and possess TRPM2, which may contribute to stroke-related pathological responses. We show that TRPM2 mRNA is present in the human C13 microglial cell line and is reduced by antisense treatment. Activation of C13 cells by interleukin-1beta leads to a fivefold increase of TRPM2 mRNA demonstrating transcriptional regulation. To confirm mRNA distribution correlated with functional expression, we combined electrophysiology, Ca2+ imaging, and antisense approaches. C13 microglia exhibited, when stimulated with hydrogen peroxide (H2O2), increased [Ca2+]i, which was reduced by antisense treatment. Moreover, patch-clamp recordings from C13 demonstrated that increased intracellular adenosine diphosphoribose (ADPR) or extracellular H2O2 induced an inward current, consistent with activation of TRPM2. In addition we confirm the functional expression of a TRPM2-like conductance in primary microglial cultures derived from rats. Activation of TRPM2 in microglia during ischemic brain injury may mediate key aspects of microglial pathophysiological responses.
Fonfria
Elena
E
Neurology and GI CEDD, GlaxoSmithKline, Harlow, UK.
Mattei
Cesar
C
Hill
Kerstin
K
Brown
Jon T
JT
Randall
Andrew
A
Benham
Christopher D
CD
Skaper
Stephen D
SD
Campbell
Colin A
CA
Crook
Barry
B
Murdock
Paul R
PR
Wilson
Jennifer M
JM
Maurio
Frank P
FP
Owen
Davina E
DE
Tilling
Paula L
PL
McNulty
Shaun
S
D000818:Animals; D001483:Base Sequence; D020013:Calcium Signaling / Q000187:drug effects; D002460:Cell Line; D002490:Central Nervous System / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D008297:Male; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D020768:Middle Cerebral Artery; D016372:RNA, Antisense / Q000008:administration & dosage / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020521:Stroke / Q000235:genetics* / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000235:genetics* / Q000378:metabolism*; D014018:Tissue Distribution
D007375:Interleukin-1; D016372:RNA, Antisense; D012333:RNA, Messenger; D050053:TRPM Cation Channels; D006861:Hydrogen Peroxide