title: Peroxisome proliferator-activated receptor-alpha agonist fenofibrate regulates IL-12 family cytokine expression in the CNS: relevance to multiple sclerosis.
abstract: The interleukin-12 (IL-12) family of cytokines which includes IL-12, IL-23, and IL-27 play critical roles in T cell differentiation and are important modulators of multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Previously, we demonstrated that peroxisome proliferator-activated receptor (PPAR) -alpha agonists suppress the development of EAE. The present studies demonstrated that the PPAR-alpha agonist fenofibrate inhibited the secretion of IL-12p40, IL-12p70 (p35/p40), IL-23 (p19/p40), and IL-27p28 by lipopolysaccharide-stimulated microglia. The cytokines interferon-gamma and tumor necrosis factor-alpha also stimulated IL-12 p40 and IL-27 p28 expression by microglia, which was suppressed by fenofibrate. Furthermore, fenofibrate inhibited microglial expression of CD14 which plays a critical role in TLR signaling, suggesting a mechanism by which this PPAR-alpha agonist regulates the production of these pro-inflammatory molecules. In addition, fenofibrate suppressed the secretion of IL-12p40, IL-23, and IL-27p28 by lipopolysaccharide-stimulated astrocytes. Importantly, fenofibrate suppression of EAE was associated with decreased expression of IL-12 family cytokine mRNAs as well as mRNAs encoding TLR4, CD14, and MyD88 known to play critical roles in MyD88-dependent TLR signaling. These novel observations suggest that PPAR-alpha agonists including fenofibrate may modulate the development of EAE, at least in part, by suppressing the production of IL-12 family cytokines and MyD88-dependent signaling.
authors.affiliation: Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
authors.forename: Jihong
authors.initials: J
authors.lastname: Xu
authors.forename: Michael K
authors.initials: MK
authors.lastname: Racke
authors.forename: Paul D
authors.initials: PD
authors.lastname: Drew
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D011345:Fenofibrate / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D018664:Interleukin-12 / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000187:drug effects*; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D047493:PPAR alpha / Q000819:agonists*; D011134:Polysaccharides / Q000494:pharmacology
chemical_list: D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D053594:Myeloid Differentiation Factor 88; D047493:PPAR alpha; D011134:Polysaccharides; D018664:Interleukin-12; D011345:Fenofibrate