The Cannabinoid 2 Receptor (CB2R) Alleviates Inflammatory and Oxidative Stress in Lipopolysaccharide-Induced BV-2 Cells and Regulates M1/M2 Polarization
JOURNAL OF BIOMATERIALS AND TISSUE ENGINEERING
Authors: Wang, Lei; Zhao, Jing; Yan, Hong-Yan; Peng, Qiang; Dai, Yong; Zhang, Yi
Background : Microglia, which participates in the inflammatory responses in the CNS, can be polarized into M1 and M2 phenotypes, showing many functional properties such as the production of inflammation association molecules. The main aim of this study is to explore whether CB2R is involved in the transformation of BV-2 cells from M1 to M2 to reduce inflammation and oxidative stress, thus promoting the repair of damaged nerves. Material and Methods: The viability of BV-2 cells was detected by CCK-8 assay. For the analysis of the phenotypic properties of BV-2 cells, we further detected the expression of M1 markers (CD32, iNOS), M2 marker (Arg1) and CB2R using western blot or immunofluorescence. After transfection into cells, the overexpressed CB2R was treated with CB2R inhibitor (AM630), then the functional properties of BV-2 cell types regarding cytokine expression profiles were assessed by measuring the production of IL-6, IL-1 beta, TNF-alpha, and ROS with ELISA assay. In addition, the neurotrophic factors, including NRF-2, HO-1 and NGF, were detected by western blot. Results : Under M1 conditions, BV-2 cells were overexpressed with CD32 and iNOS, and M1-polarizing conditions induced the production of pro-inflammatory cytokines and ROS. The overexpression of CB2R promotes the transformation from M1 into M2 phenotype in BV-2 cells, following with the upregulation of Arg-1. Meanwhile, the neurotrophic factors were increased in LPS-induced BV-2 cells after CB2R transfection. All these effects were attenuated by AM630. Conclusion : Targeting CB2R might be a new therapeutic option for the treatment of nerve injury and neurological diseases associated with neuroinflammation.
DIFFERENTIAL RESPONSE TO INTRAHIPPOCAMPAL INTERLEUKIN-4/INTERLEUKIN-13 IN AGED AND EXERCISE MICE
Authors: Littlefield, Alyssa; Kohman, Rachel A.
Normal aging is associated with low-grade neuroinflammation that results from age-related priming of microglial cells. Further, aging alters the response to several anti-inflammatory factors, including interleukin (IL)-4 and IL-13. One intervention that has been shown to modulate microglia activation in the aged brain, both basally and following an immune challenge, is exercise. However, whether engaging in exercise can improve responsiveness to anti-inflammatory cytokines is presently unknown. The current study evaluated whether prior exercise training increases sensitivity to anti-inflammatory cytokines that promote the M2 (alternative) microglia phenotype in adult (5-month-old) and aged (23-month-old) C57BL/6J mice. After 8 weeks of exercise or control housing, mice received bilateral hippocampal injections of an IL-411L-13 cocktail or vehicle. Twenty-four hours later hippocampal samples were collected and analyzed for expression of genes associated with the M1 (inflammatory) and M2 microglia phenotypes. Results show that IL-4/IL-13 administration increased expression of the M2-associated genes found in inflammatory zone 1 (Fizz1), chitinase-like 3 (Ym1), Arginase-1 (Arg1), SOCS1, IL-1ra, and CD206. In response to IL-4/IL-13 administration, aged mice showed increased hippocampal expression of the M2 -related genes Arg1, SOCS1, Ym1, and CD206 relative to adult mice. Aged mice also showed increased expression of IL-1 beta relative to adults, which was unaffected by wheel running or IL-4/IL-13. Wheel running was found to have modest effects on expression of Ym1 and Fizz1 in aged and adult mice. Collectively, our findings indicate that aged mice show a differential response to anti-inflammatory cytokines relative to adult mice and that exercise has limited effects on modulating this response. (C) 2016 IBRO. Published by Elsevier Ltd. All rights reserved.