Elevated COX2 expression and PGE2 production by downregulation of RXRα in senescent macrophages.
Increased systemic level of inflammatory cytokines leads to numerous age-related diseases. In senescent macrophages, elevated prostaglandin E2 (PGE2) production contributes to the suppression of T cell function with aging, which increases the susceptibility to infections. However, the regulation of these inflammatory cytokines and PGE2 with aging still remains unclear. We have verified that cyclooxygenase (COX)-2 expression and PGE2 production are higher in LPS-stimulated macrophages from old mice than that from young mice. Downregulation of RXRα, a nuclear receptor that can suppress NF-κB activity, mediates the elevation of COX2 expression and PGE2 production in senescent macrophages. We also have found less induction of ABCA1 and ABCG1 by RXRα agonist in senescent macrophages, which partially accounts for high risk of atherosclerosis in aged population. Systemic treatment with RXRα antagonist HX531 in young mice increases COX2, TNF-α, and IL-6 expression in splenocytes. Our study not only has outlined a mechanism of elevated NF-κB activity and PGE2 production in senescent macrophages, but also provides RXRα as a potential therapeutic target for treating the age-related diseases.
Department of Geratology, Liaoning Jinqiu Hospital, Shenyang 110015, PR China. Electronic address: huiminchen.jq@gmail.com.
Huimin
H
Chen
Feng
F
Ma
Xiaona
X
Hu
Ting
T
Jin
Chuhui
C
Xiong
Xiaochun
X
Teng
D000375:Aging; D000818:Animals; D002460:Cell Line; D016922:Cellular Senescence; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000276:immunology; D015232:Dinoprostone / Q000276:immunology*; D015536:Down-Regulation; D008070:Lipopolysaccharides / Q000276:immunology; D008264:Macrophages / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000276:immunology; D047490:Retinoid X Receptor alpha / Q000235:genetics* / Q000276:immunology; D015854:Up-Regulation
D008070:Lipopolysaccharides; D016328:NF-kappa B; D047490:Retinoid X Receptor alpha; D051546:Cyclooxygenase 2; D015232:Dinoprostone
9-cis-retinoid acid; 9cRA; ABCA1; ABCG1; ATP-binding cassette transporter A1; ATP-binding cassette transporter G1; Aging; COX2; Macrophage; NF-κB; PGE2; RXR; RXRα; TLR; cyclooxygenase 2; prostaglandin E2; retinoid X receptor alpha; toll-like receptor