title: Elevated MicroRNA-33 in Sarcoidosis and a Carbon Nanotube Model of Chronic Granulomatous Disease.
abstract: We established a murine model of multiwall carbon nanotube (MWCNT)-induced chronic granulomatous disease, which resembles human sarcoidosis pathology. At 60 days after oropharyngeal MWCNT instillation, bronchoalveolar lavage (BAL) cells from wild-type mice exhibit an M1 phenotype with elevated proinflammatory cytokines and reduced peroxisome proliferator-activated receptor γ (PPARγ)-characteristics also present in human sarcoidosis. Based upon MWCNT-associated PPARγ deficiency, we hypothesized that the PPARγ target gene, ATP-binding cassette (ABC) G1, a lipid transporter with antiinflammatory properties, might also be repressed. Results after MWCNT instillation indicated significantly repressed ABCG1, but, surprisingly, lipid transporter ABCA1 was also repressed, suggesting a possible second pathway. Exploration of potential regulators revealed that microRNA (miR)-33, a lipid transporter regulator, was strikingly elevated (13.9 fold) in BAL cells from MWCNT-instilled mice but not sham control mice. Elevated miR-33 was also detected in murine granulomatous lung tissue. In vitro studies confirmed that lentivirus-miR-33 overexpression repressed both ABCA1 and ABCG1 (but not PPARγ) in cultured murine alveolar macrophages. BAL cells of patients with sarcoidosis also displayed elevated miR-33 together with reduced ABCA1 and ABCG1 messenger RNA and protein compared with healthy control subjects. Moreover, miR-33 was elevated within sarcoidosis granulomatous tissue. The findings suggest that alveolar macrophage miR-33 is up-regulated by proinflammatory cytokines and may perpetuate chronic inflammatory granulomatous disease by repressing antiinflammatory functions of ABCA1 and ABCG1 lipid transporters. The results also suggest two possible pathways for transporter dysregulation in granulomatous disease-one associated with intrinsic PPARγ status and the other with miR-33 up-regulation triggered by environmental challenges, such as MWCNT.
authors.affiliation: 1 Division of Pulmonary, Critical Care, and Sleep Medicine, East Carolina University, Greenville, North Carolina.
authors.forename: Barbara P
authors.initials: BP
authors.lastname: Barna
authors.affiliation: 1 Division of Pulmonary, Critical Care, and Sleep Medicine, East Carolina University, Greenville, North Carolina.
authors.forename: Matthew
authors.initials: M
authors.lastname: McPeek
authors.affiliation: 1 Division of Pulmonary, Critical Care, and Sleep Medicine, East Carolina University, Greenville, North Carolina.
authors.forename: Anagha
authors.initials: A
authors.lastname: Malur
authors.affiliation: 2 Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Fessler
authors.affiliation: Departments of 3 Physiology.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wingard
authors.affiliation: 4 Pathology, and.
authors.forename: Larry
authors.initials: L
authors.lastname: Dobbs
authors.affiliation: 5 Surgery, East Carolina University, Greenville, North Carolina; and.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Verbanac
authors.affiliation: 1 Division of Pulmonary, Critical Care, and Sleep Medicine, East Carolina University, Greenville, North Carolina.
authors.forename: Mark
authors.initials: M
authors.lastname: Bowling
authors.affiliation: 6 Division of Pulmonary and Critical Care, Medical College of Albany, Albany, New York.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Judson
authors.affiliation: 1 Division of Pulmonary, Critical Care, and Sleep Medicine, East Carolina University, Greenville, North Carolina.
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: Thomassen
mesh_terms: D064286:ATP Binding Cassette Transporter 1; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1 / Q000378:metabolism; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D004195:Disease Models, Animal; D006105:Granulomatous Disease, Chronic / Q000139:chemically induced* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008055:Lipids / Q000737:chemistry; D016676:Macrophages, Alveolar / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism*; D008954:Models, Biological; D037742:Nanotubes, Carbon / Q000009:adverse effects*; D012507:Sarcoidosis / Q000235:genetics*
chemical_list: D064286:ATP Binding Cassette Transporter 1; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D008055:Lipids; C550416:MIRN33a microRNA, human; D026901:Membrane Transport Proteins; D035683:MicroRNAs; C550417:Mirn33 microRNA, mouse; D037742:Nanotubes, Carbon
keywords: carbon nanotube; lipid transporters; microRNA; murine model; sarcoidosis