title: Major role of adipocyte prostaglandin E2 in lipolysis-induced macrophage recruitment.
abstract: Obesity induces accumulation of adipose tissue macrophages (ATMs), which contribute to both local and systemic inflammation and modulate insulin sensitivity. Adipocyte lipolysis during fasting and weight loss also leads to ATM accumulation, but without proinflammatory activation suggesting distinct mechanisms of ATM recruitment. We examined the possibility that specific lipid mediators with anti-inflammatory properties are released from adipocytes undergoing lipolysis to induce macrophage migration. In the present study, we showed that conditioned medium (CM) from adipocytes treated with forskolin to stimulate lipolysis can induce migration of RAW 264.7 macrophages. In addition to FFAs, lipolytic stimulation increased release of prostaglandin E2(PGE2) and prostaglandin D2(PGD2), reflecting cytosolic phospholipase A2α activation and enhanced cyclooxygenase (COX) 2 expression. Reconstituted medium with the anti-inflammatory PGE2potently induced macrophage migration while different FFAs and PGD2had modest effects. The ability of CM to induce macrophage migration was abolished by treating adipocytes with the COX2 inhibitor sc236 or by treating macrophages with the prostaglandin E receptor 4 antagonist AH23848. In fasted mice, macrophage accumulation in adipose tissue coincided with increases of PGE2levels and COX1 expression. Collectively, our data show that adipocyte-originated PGE2with inflammation suppressive properties plays a significant role in mediating ATM accumulation during lipolysis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, Jiangsu, 215123, China Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO 63110 Department of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China.
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Hu
authors.affiliation: Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Vincenza
authors.initials: V
authors.lastname: Cifarelli
authors.affiliation: Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, Jiangsu, 215123, China.
authors.forename: Shishuo
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 14220 Prague 4, Czech Republic.
authors.forename: Ondrej
authors.initials: O
authors.lastname: Kuda
authors.affiliation: Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO 63110 nabumrad@dom.wustl.edu xsu@suda.edu.cn.
authors.forename: Nada A
authors.initials: NA
authors.lastname: Abumrad
authors.affiliation: Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, Jiangsu, 215123, China Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO 63110 nabumrad@dom.wustl.edu xsu@suda.edu.cn.
authors.forename: Xiong
authors.initials: X
authors.lastname: Su
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002633:Chemotaxis; D051545:Cyclooxygenase 1 / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000235:genetics; D015232:Dinoprostone / Q000378:metabolism*; D004789:Enzyme Activation; D005215:Fasting; D015971:Gene Expression Regulation, Enzymologic; D054513:Group IV Phospholipases A2 / Q000378:metabolism; D008066:Lipolysis; D008264:Macrophages / Q000166:cytology*; D051379:Mice; D000067996:RAW 264.7 Cells
chemical_list: D016718:Arachidonic Acid; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D054513:Group IV Phospholipases A2; D015232:Dinoprostone
keywords: adipose tissue; cyclooxygenase; eicosanoids; extracellular signal-regulated kinase; fatty acid; inflammation; lipase