Activation of Dopamine D2 Receptor Suppresses Neuroinflammation Through αB-Crystalline by Inhibition of NF-κB Nuclear Translocation in Experimental ICH Mice Model.
BACKGROUND AND PURPOSE
Inflammatory injury plays a critical role in intracerebral hemorrhage (ICH)-induced secondary brain injury. Recently, dopamine D2 receptor (DRD2) is identified as an important component controlling innate immunity and inflammatory response in central nervous system, and αB-crystallin (CRYAB) is a potent negative regulator on inflammatory pathways. Here, we sought to investigate the role of DRD2 on neuroinflammation after experimental ICH and the potential mechanism mediated by CRYAB.


METHODS
Two hundred and twenty-four (224) male CD-1 mice were subjected to intrastriatal infusion of bacterial collagenase or autologous blood. Two DRD2 agonists quinpirole and ropinirole were administrated by daily intraperitoneal injection starting at 1 hour after ICH. DRD2 and CRYAB in vivo knockdown was performed 48 hours before ICH insult. Behavioral deficits and brain water content, Western blots, immunofluorescence staining, coimmunoprecipitation (Co-IP) assay, and proteome cytokine array were evaluated.


RESULTS
Endogenous DRD2 and CRYAB expressions were increased after ICH. DRD2 knockdown aggravated the neurobehavioral deficits and the pronounced cytokine expressions. DRD2 activation by quinpirole and ropinirole ameliorated neurological outcome, brain edema, interleukin-1β, and monocyte chemoattractant protein-1 expression, as well as microglia/macrophages activation, in the perihematomal region. These effects were abolished by pretreatment with CRYAB siRNAs. Quinpirole enhanced cytoplasmic binding activity between CRYAB and NF-κB and decreased nuclear NF-κB expression. Similar therapeutic benefits were observed using autologous blood injection model and intranasal delivery of quinpirole.


CONCLUSIONS
DRD2 may have anti-inflammatory effects after ICH. DRD2 agonists inhibited neuroinflammation and attenuated brain injury after ICH, which is probably mediated by CRYAB and enhanced cytoplasmic binding activity with NF-κB.
['Zhang|Yang|Y|', 'Chen|Yujie|Y|', 'Wu|Jiang|J|', 'Manaenko|Anatol|A|', 'Yang|Peng|P|', 'Tang|Jiping|J|', 'Fu|Weiling|W|', 'Zhang|John H|JH|']
D021581:Active Transport, Cell Nucleus D000818:Animals D002467:Cell Nucleus D002543:Cerebral Hemorrhage D004195:Disease Models, Animal D007249:Inflammation D008297:Male D051379:Mice D008815:Mice, Inbred Strains D016328:NF-kappa B D017448:Receptors, Dopamine D2 D038203:alpha-Crystallin B Chain
dopamine D2 receptor neuroinflammation NF-κB intracerebral hemorrhage B-crystalline