Tumor necrosis factor alpha, citrullination, and peptidylarginine deiminase 4 in lung and joint inflammation
Warner, Thomas F.
Nicholas, Anthony P.
Lundblad, Lennart K. A
Thompson, Paul R
Shelef, Miriam A.
UMass Chan AffiliationsDepartment of Biochemistry and Molecular Pharmacology
Document TypeJournal Article
Peptidylarginine deiminase 4
Enzymes and Coenzymes
MetadataShow full item record
AbstractBACKGROUND: The relationship between lung and joint inflammation in rheumatoid arthritis is poorly understood. Lung inflammation with resultant protein citrullination may trigger anti-citrullinated protein antibodies, inflammation, and arthritis. Alternatively, lung and joint inflammation may be two manifestations of a single underlying pathology. The lung has increased citrullination and TNF-alpha levels are high in rheumatoid arthritis; however, it is unknown if TNF-alpha can induce lung protein citrullination. The citrullinating enzyme peptidylarginine deiminase 4 (PAD4) exacerbates TNF-alpha-induced arthritis, but a role for PAD4 in lung citrullination and TNF-alpha-induced lung inflammation has not been explored. Our aim was to use TNF-alpha-overexpressing mice to clarify the intersection of TNF-alpha, citrullination, PAD4, arthritis, and lung inflammation. METHODS: Lung protein citrullination in wild-type mice, mice that overexpress TNF-alpha systemically (TNF(+)), TNF(+)PAD4(+/+), and TNF(+)PAD4(-/-) mice was quantified by both gel electrophoresis using a citrulline probe and western blot. Hematoxylin and eosin (HandE)-stained lung sections from TNF(+)PAD4(+/+) and TNF(+)PAD4(-/-) mice were scored for lung inflammation. HandE-stained ankle joint sections from mice that overexpress TNF-alpha only in the lungs were assessed for arthritis. RESULTS: TNF(+) mice have increased lung protein citrullination. TNF(+)PAD4(-/-) mice do not have significantly reduced lung protein citrullination, but do have decreased lung inflammation compared to TNF(+)PAD4(+/+) mice. Mice that overexpress TNF-alpha only in the lungs do not develop arthritis. CONCLUSIONS: PAD4 exacerbates lung inflammation downstream of TNF-alpha without having a major role in generalized protein citrullination in inflamed lungs. Also, TNF-alpha-induced lung inflammation is not sufficient to drive murine arthritis.
SourceArthritis Res Ther. 2016 Jul 22;18(1):173. doi: 10.1186/s13075-016-1068-0. Link to article on publisher's site
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/39976
RightsCopyright © The Author(s). 2016. Open Access.
Except where otherwise noted, this item's license is described as Copyright © The Author(s). 2016. Open Access.