C3a receptor modulation of granulocyte infiltration after murine focal cerebral ischemia is reperfusion dependent.
The complement anaphylatoxin C3a contributes to injury after cerebral ischemia in mice. This study assesses the effect of C3a receptor antagonist (C3aRA) on leukocyte infiltration into the ischemic zone. Transient or permanent middle cerebral artery occlusion (MCAO) was induced in wild-type C57Bl/6 mice. Intraperitoneal C3aRA or vehicle was administered 45 mins before or 1 h after occlusion. Twenty-four hours after occlusion, we harvested brain tissue and purified inflammatory cells using flow cytometry. Soluble intercellular adhesion molecule (ICAM)-1 protein levels were assessed using enzyme-linked immunosorbent assays, and ICAM-1 and C3a receptor (C3aR) expression was confirmed via immunohistochemistry. In the transient MCAO model, animals receiving C3aRA showed smaller strokes, less upregulation of C3aR-positive granulocytes, and less ICAM-1 protein on endothelial cells than vehicle-treated animals; no significant differences in other inflammatory cell populations were observed. C3a receptor antagonist-treated and vehicle-treated animals showed no differences in stroke volume or inflammatory cell populations after permanent MCAO. These data suggest that blocking the binding of C3a to C3aR modulates tissue injury in reperfused stroke by inhibiting the recruitment of neutrophils to the ischemic zone. It further establishes antagonism of the C3a anaphylatoxin as a promising strategy for ameliorating injury after ischemia/reperfusion.
Ducruet
Andrew F
AF
Department of Neurological Surgery, Columbia University, New York, New York 10032, USA. afd12@columbia.edu
Hassid
Benjamin G
BG
Mack
William J
WJ
Sosunov
Sergei A
SA
Otten
Marc L
ML
Fusco
David J
DJ
Hickman
Zachary L
ZL
Kim
Grace H
GH
Komotar
Ricardo J
RJ
Mocco
J
J
Connolly
E Sander
ES
D000706:Anaphylatoxins / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001559:Benzhydryl Compounds / Q000494:pharmacology*; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D015926:Complement C3a / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004195:Disease Models, Animal; D005434:Flow Cytometry; D006098:Granulocytes / Q000473:pathology*; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018696:Neuroprotective Agents / Q000494:pharmacology; D011951:Receptors, Complement / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology
D000706:Anaphylatoxins; D001559:Benzhydryl Compounds; D018696:Neuroprotective Agents; D011951:Receptors, Complement; C431907:SB 290157; D018799:Intercellular Adhesion Molecule-1; D015926:Complement C3a; D001120:Arginine