title: Leptin modulates innate and adaptive immune cell recruitment after cigarette smoke exposure in mice.
abstract: Leptin, a pleiotropic type I cytokine, was recently demonstrated to be expressed by resident lung cells in chronic obstructive pulmonary disease patients and asymptomatic smokers. To elucidate the functional role of leptin in the onset of chronic obstructive pulmonary disease, we tested leptin-deficient ob/ob mice (C57BL/6), leptin receptor-deficient db/db mice (C57BKS), and littermates in a model of cigarette smoke (CS)-induced pulmonary inflammation. Wild-type (WT) C57BL/6 mice were exposed for 4 or 24 wk to control air or CS. Pulmonary leptin expression was analyzed by immunohistochemistry and real-time PCR. Pulmonary inflammation upon 4 wk CS exposure was evaluated in bronchoalveolar lavage fluid (BALF) and lung tissue of WT, ob/ob, and db/db mice. Immunohistochemical analysis revealed leptin expression in bronchial epithelial cells, pneumocytes, alveolar macrophages, and bronchial/vascular smooth muscle cells. The 4 and 24 wk CS exposure increased leptin expression in bronchial epithelial cells and pneumocytes versus air-exposed WT mice (p<0.05). The 4 wk CS exposure resulted in increased accumulation of neutrophils, dendritic cells, macrophages, and lymphocytes in BALF and lung tissue of WT, ob/ob, and db/db mice. CS-exposed ob/ob and db/db mice showed in general higher numbers of neutrophils and lower numbers of CD4+, CD8+, and dendritic cells versus CS-exposed WT mice. Consistently, CXCL1 levels were enhanced in BALF of CS-exposed ob/ob and db/db mice versus WT mice (p<0.05). Exogenous leptin administration completely restored the skewed inflammatory profile in ob/ob mice. These data reveal an important role of leptin in modulating innate and adaptive immunity after CS inhalation in mice.
authors.affiliation: Department of Respiratory Medicine, NUTRIM School for Nutrition, Toxicology and Metabolism, Horn, The Netherlands. j.vernooy@pul.unimaas.nl
authors.forename: Juanita H J
authors.initials: JH
authors.lastname: Vernooy
authors.forename: Ken R
authors.initials: KR
authors.lastname: Bracke
authors.forename: Nadja E A
authors.initials: NE
authors.lastname: Drummen
authors.forename: Nele S A
authors.initials: NS
authors.lastname: Pauwels
authors.forename: Lennart
authors.initials: L
authors.lastname: Zabeau
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: van Suylen
authors.forename: Jan
authors.initials: J
authors.lastname: Tavernier
authors.forename: Guy F
authors.initials: GF
authors.lastname: Joos
authors.forename: Emiel F M
authors.initials: EF
authors.lastname: Wouters
authors.forename: Guy G
authors.initials: GG
authors.lastname: Brusselle
mesh_terms: D056704:Adaptive Immunity / Q000276:immunology*; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D007113:Immunity, Innate / Q000276:immunology*; D007150:Immunohistochemistry; D020738:Leptin / Q000276:immunology* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011014:Pneumonia / Q000209:etiology* / Q000276:immunology* / Q000378:metabolism; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology / Q000276:immunology; D054411:Receptors, Leptin / Q000172:deficiency / Q000276:immunology; D020545:Respiratory Mucosa / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D020738:Leptin; D054411:Receptors, Leptin; D014028:Tobacco Smoke Pollution