title: Interactions between IL-32 and tumor necrosis factor alpha contribute to the exacerbation of immune-inflammatory diseases.
abstract: IL-32 is a newly described cytokine in the human found to be an in vitro inducer of tumor necrosis factor alpha (TNFalpha). We examined the in vivo relationship between IL-32 and TNFalpha, and the pathologic role of IL-32 in the TNFalpha-related diseases - arthritis and colitis. We demonstrated by quantitative PCR assay that IL-32 mRNA was expressed in the lymphoid tissues, and in stimulated peripheral T cells, monocytes, and B cells. Activated T cells were important for IL-32 mRNA expression in monocytes and B cells. Interestingly, TNFalpha reciprocally induced IL-32 mRNA expression in T cells, monocyte-derived dendritic cells, and synovial fibroblasts. Moreover, IL-32 mRNA expression was prominent in the synovial tissues of rheumatoid arthritis patients, especially in synovial-infiltrated lymphocytes by in situ hybridization. To examine the in vivo relationship of IL-32 and TNFalpha, we prepared an overexpression model mouse of human IL-32beta (BM-hIL-32) by bone marrow transplantation. Splenocytes of BM-hIL-32 mice showed increased expression and secretion of TNFalpha, IL-1beta, and IL-6 especially in response to lipopolysaccharide stimulation. Moreover, serum TNFalpha concentration showed a clear increase in BM-hIL-32 mice. Cell-sorting analysis of splenocytes showed that the expression of TNFalpha was increased in resting F4/80+ macrophages, and the expression of TNFalpha, IL-1beta and IL-6 was increased in lipopolysaccharide-stimulated F4/80+ macrophages and CD11c+ dendritic cells. In fact, BM-hIL-32 mice showed exacerbation of collagen-antibody-induced arthritis and trinitrobenzen sulfonic acid-induced colitis. In addition, the transfer of hIL-32beta-producing CD4+ T cells significantly exacerbated collagen-induced arthritis, and a TNFalpha blockade cancelled the exacerbating effects of hIL-32beta. We therefore conclude that IL-32 is closely associated with TNFalpha, and contributes to the exacerbation of TNFalpha-related inflammatory arthritis and colitis.
authors.affiliation: Department of Allergy and Rheumatology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. shoda-tky@umin.ac.jp
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shoda
authors.forename: Keishi
authors.initials: K
authors.lastname: Fujio
authors.forename: Yumi
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Akiko
authors.initials: A
authors.lastname: Okamoto
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Sawada
authors.forename: Yuta
authors.initials: Y
authors.lastname: Kochi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D003092:Colitis / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D017403:In Situ Hybridization; D053583:Interleukin-1beta / Q000276:immunology / Q000378:metabolism; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism; D007378:Interleukins / Q000276:immunology / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013583:Synovial Membrane / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014302:Trinitrobenzenesulfonic Acid / Q000633:toxicity; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism*
chemical_list: C496971:IL32 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D007378:Interleukins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D014302:Trinitrobenzenesulfonic Acid