title: Eosinophil Peroxidase Catalyzed Protein Carbamylation Participates in Asthma.
abstract: The biochemical mechanisms through which eosinophils contribute to asthma pathogenesis are unclear. Here we show eosinophil peroxidase (EPO), an abundant granule protein released by activated eosinophils, contributes to characteristic asthma-related phenotypes through oxidative posttranslational modification (PTM) of proteins in asthmatic airways through a process called carbamylation. Using a combination of studies we now show EPO uses plasma levels of the pseudohalide thiocyanate (SCN-) as substrate to catalyze protein carbamylation, as monitored by PTM of protein lysine residues into Nϵ-carbamyllysine (homocitrulline), and contributes to the pathophysiological sequelae of eosinophil activation. Studies using EPO-deficient mice confirm EPO serves as a major enzymatic source for protein carbamylation during eosinophilic inflammatory models, including aeroallergen challenge. Clinical studies similarly revealed significant enrichment in carbamylation of airway proteins recovered from atopic asthmatics versus healthy controls in response to segmental allergen challenge. Protein-bound homocitrulline is shown to be co-localized with EPO within human asthmatic airways. Moreover, pathophysiologically relevant levels of carbamylated protein either incubated with cultured human airway epithelial cells in vitro, or provided as an aerosolized exposure in non-sensitized mice, induced multiple asthma-associated phenotypes including induction of mucin, Th2 cytokines, IFNγ, TGFβ, and epithelial cell apoptosis. Studies with scavenger receptor-A1 null mice reveal reduced IL-13 generation following exposure to aerosolized carbamylated protein, but no changes in other asthma-related phenotypes. In summary, EPO-mediated protein carbamylation is promoted during allergen-induced asthma exacerbation, and can both modulate immune responses and trigger a cascade of many of the inflammatory signals present in asthma.
authors: From the Departments of Cellular and Molecular Medicine.
authors: Zeneng
authors: Z
authors: Wang
authors: From the Departments of Cellular and Molecular Medicine.
authors: Joseph A
authors: JA
authors: DiDonato
authors: From the Departments of Cellular and Molecular Medicine.
authors: Jennifer
authors: J
authors: Buffa
authors: Pathobiology.
authors: Suzy A
authors: SA
authors: Comhair
authors: Pathobiology.
authors: Mark A
authors: MA
authors: Aronica
authors: Pathobiology, Pulmonary Medicine, and.
authors: Raed A
authors: RA
authors: Dweik
authors: the Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona 85259.
authors: Nancy A
authors: NA
authors: Lee
authors: the Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona 85259.
authors: James J
authors: JJ
authors: Lee
authors: the Division of Pulmonary, Critical Care & Sleep Medicine, East Carolina University, Greenville, North Carolina 27834, and.
authors: Mary Jane
authors: MJ
authors: Thomassen
authors: the Division of Pulmonary and Critical Care Medicine, Thomas Jefferson University and Hospital, Philadelphia, Pennsylvania 19107.
authors: Mani
authors: M
authors: Kavuru
authors: Pathobiology, Pulmonary Medicine, and.
authors: Serpil C
authors: SC
authors: Erzurum
authors: From the Departments of Cellular and Molecular Medicine, Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio 44195, hazens@ccf.org.
authors: Stanley L
authors: SL
authors: Hazen
mesh_terms: D000072283:A549 Cells; D000818:Animals; D001249:Asthma / Q000276:immunology* / Q000473:pathology; D002956:Citrulline / Q000031:analogs & derivatives* / Q000276:immunology; D047209:Eosinophil Peroxidase / Q000276:immunology*; D004804:Eosinophils / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D018793:Interleukin-13 / Q000276:immunology; D051379:Mice; D011499:Protein Processing, Post-Translational / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000276:immunology
chemical_list: C573415:IFNG protein, human; C000611649:IFNG protein, mouse; D018793:Interleukin-13; D016212:Transforming Growth Factor beta; C001352:homocitrulline; D002956:Citrulline; D007371:Interferon-gamma; D047209:Eosinophil Peroxidase
keywords: asthma; eosinophil; inflammation; peroxidase; post-translational modification (PTM)