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The Anti‐Inflammatory Cytokine IL‐19 Reduces mRNA‐Stability Protein HuR Function in Human Vascular Smooth Muscle Cells
Author(s) -
Herman Allison,
Haines Dale,
Autieri Michael V.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1209.11
Subject(s) - vascular smooth muscle , inflammation , messenger rna , cytoplasm , microbiology and biotechnology , proinflammatory cytokine , transfection , cytokine , downregulation and upregulation , rna binding protein , tumor necrosis factor alpha , biology , chemistry , immunology , cell culture , endocrinology , biochemistry , gene , smooth muscle , genetics
Vascular diseases such as atherosclerosis and restenosis are often exacerbated by associated inflammation. Vascular smooth muscle cells (VSMCs) respond to injury and are capable of producing pro‐inflammatory cytokines which amplify the inflammatory response. Identification of compounds which attenuate this response is an important therapeutic goal. Presently, little is known about the potential for endogenously expressed anti‐inflammatory cytokines to attenuate inflammation and have vascular protective effects. Interleuken‐19 (IL‐19) is a newly identified member of the IL‐10 anti‐inflammatory family. IL‐19 expression can be induced in VSMCs by pro‐inflammatory cytokines and is capable of reducing the stability and abundance of pro‐inflammatory mRNA transcripts. HuR is an mRNA stability protein which functions to stabilize pro‐inflammatory transcripts by shuttling from the nucleus to the cytoplasm where it binds to AU‐rich elements within the 3′ UTR of transcripts. Nuclear to cytoplasmic shuttling is essential for HuR activity. We previously determined that treatment of VSMCs with IL‐19 transiently reduces HuR abundance in the cytoplasm, by a presently unknown mechanism. In the present study we show that overexpression of HuR significantly increases VSMC proliferation. We hypothesize that IL‐19 inhibits HuR translocation to the cytoplasm by altering chaperone protein function, abundance, or both. To test this hypothesis, VSMCs were transfected with epitope‐tagged HuR expression plasmids, followed by treatment with TNFα alone, IL‐19, or both, to determine if any HuR‐interacting proteins are differentially regulated by inflammation or IL‐19 to alter HuR activity. Protein extracts were prepared from each treatment group and HuR was immunoprecipitated and proteomic analysis (MASS SPEC) was performed to identify HuR‐interacting proteins in each of these conditions. Numerous novel protein interactions with HuR are altered by the different inflammatory treatment conditions. The roles of many of these novel interacting proteins involve RNA‐binding and post‐transcriptional regulation based on the literature. Inflammation‐modulated differential HuR protein‐ protein interactions provide a framework showing mRNA stability can be modified by HuR chaperone proteins VSMCs, which is a novel direction of study for inflammation. The proteins identified could lead to a better understanding of the mechanisms associated with vascular inflammatory diseases such as atherosclerosis and provide targets for new therapeutic agents. Support or Funding Information This work was supported by grants HL115575 and HL117724 from the National Heart Lung, and Blood Institute of the National Institutes of Health, and Grant 13GRNT1685003 from the American Heart Association to MVA