Ming Shi Chang

IL-19 Induces Production of IL-6 and TNF-α and Results in Cell Apoptosis Through TNF-α

IL-10 is an immunosuppressive cytokine in the immune system. It was in clinical trail as an anti-inflammatory therapy for inflammatory bowel disease and various autoimmune diseases such as psoriasis, rheumatoid arthritis, and multiple sclerosis. IL-19 belongs to the IL-10 family, which includes IL-10, IL-19, IL-20, IL-22, melanoma differentiation-associated gene (MDA-7, IL-24), and AK155 (IL-26). Despite a partial homology in their amino acid sequences, they are dissimilar in their biologic functions. Little is known about the biologic function and gene regulation of IL-19. To understand the gene regulation of human IL-19, we identified a human IL-19 genomic clone and analyzed its promoter region. Five fusion genes containing different regions upstream of exon 1 linked to a luciferase reporter gene were expressed in the canine kidney epithelial-like Madin-Darby canine kidney cells. A fusion gene containing 394 bp showed luciferase activity 7- to 8-fold higher than the negative control of the promoterless fusion gene. We also isolated a full-length mouse cDNA clone. Mouse IL-19 shared 71% amino acid identity with human IL-19. Treatment of monocytes with mouse IL-19 induced the production of IL-6 and TNF-α. It also induced mouse monocyte apoptosis and the production of reactive oxygen species. Taken together, our results indicate that mouse IL-19 may play some important roles in inflammatory responses because it up-regulates IL-6 and TNF-α and induces apoptosis.

Absence of an Essential Role for Thymic Stromal Lymphopoietin Receptor in Murine B-Cell Development

ABSTRACT The murine cytokine thymic stromal lymphopoietin (TSLP) supports the development of B220+ IgM+ immature B cells and induces thymocyte proliferation in vitro. Human TSLP, by contrast, activates CD11c+ dendritic cells, but not B or T cells. Recent studies have demonstrated that the receptor for TSLP consists of a heterodimer of the interleukin 7 (IL-7) α chain and a novel protein that resembles the hematopoietic cytokine receptor common γ chain. We examined signal transduction by the γ-like chains using chimeric receptor proteins. The cytoplasmic domain of the human, but not of the murine, γ-like chain, activates Jak2 and Stat5 and supports the proliferation of hematopoietic cell lines. In order to assess the role of the murine γ-like chain in vivo, we generated γ-like chain-deficient mice. Receptor-deficient mice are unresponsive to TSLP but exhibit no obvious phenotypic defects. In particular, hematopoietic cell development appeared normal. B-cell development, including the IgM+ compartment, was unaffected by loss of the TSLP pathway, as were T lymphopoiesis and lymphocyte proliferation in vitro. Cytokine receptors that utilize the common γ chain signal through the lymphocyte-specific kinase Jak3. Mice deficient in Jak3 exhibit a SCID phenotype but harbor a residual B220+ splenic lymphocyte population. We demonstrate here that this residual lymphocyte population is lost in mice lacking both the γ-like chain and Jak3.

IL-19 Induced Th2 Cytokines and Was Up-Regulated in Asthma Patients

IL-19 belongs to the IL-10 family, which includes IL-10, IL-19, IL-20, IL-22, melanoma differentiation-associated gene-7 (IL-24), and AK155 (IL-26). IL-10 has been shown to inhibit allergen-induced airway hyperreactivity and inflammation. To determine whether IL-19 was also associated with asthma, we used ELISA to analyze the serum level of IL-19 in patients with asthma and found that their serum IL-19 levels were twice those of healthy controls. Patients with a high level of IL-19 also had high levels of IL-4 and IL-13. In a dust mite-induced murine model of asthma, we found that IL-19 level in asthmatic BALB/cJ mice was also twice that of healthy control mice. IL-19 transcript was also induced in the lungs of asthmatic mice. Electroporation i.m. of the IL-19 gene into healthy mice up-regulated IL-4 and IL-5, but not IL-13. However, IL-19 up-regulated IL-13 in asthmatic mice. In vitro, IL-19 induced IL-4, IL-5, IL-10, and IL-13 production by activated T cells. Activation of T cells was required for induction of IL-13 because IL-19 did not induce IL-13 production on nonstimulated T cells. Taken together, these results demonstrated that IL-19 up-regulates Th2 cytokines on activated T cells and might play an important role in the pathogenesis of asthma.

Interleukin-20 promotes angiogenesis in a direct and indirect manner

IL-20 belongs to the IL-10 family and is involved in the pathogenesis of keratinocyte hyperproliferation in vivo. Endothelial cells express IL-20 receptors. To explore the function of IL-20 on endothelial cells, we treated human umbilical vein endothelial cells (HUVECs) and human microvascular endothelial cells (HMECs) with human IL-20 and analyzed its effect on endothelial cells. IL-20 induced proliferation of endothelial cells and the activity was specifically blocked by anti-human-IL-20 monoclonal antibody and soluble (s)IL-20 receptor (R)1 and sIL-20R2. An alternatively spliced variant of IL-20 was isolated and also was shown to induce proliferation of HUVECs and HMECs. Treatment of HUVECs with both IL-10 and IL-20 demonstrated that IL-10 antagonized the activity of IL-20 because it diminished IL-20-induced proliferation of HUVECs. IL-20 significantly induced HUVECs migration and vascular tube formation on Matrigel in vitro. In vivo, IL-20 also enhanced tumor angiogenesis. Incubation of IL-20 with HUVECs induced transcripts of bFGF, VEGF, MMP-2, MMP-9, and IL-8. Furthermore, incubation of HUVECs with IL-20 induced phosphorylation of ERK1/2, p38, and JNK. Thus, IL-20 is a pleiotropic cytokine and promotes angiogenesis.

Molecular Cloning and Functional Characterization of a Novel CC Chemokine, Stimulated T Cell Chemotactic Protein (STCP-1) That Specifically Acts on Activated T Lymphocytes

A novel human chemokine STCP-1 (stimulated T cell chemotactic protein) was isolated from an activated macrophage cDNA library. The chemokine has four cysteines positioned in a manner that identifies STCP-1 as a member of the CC chemokine family. The amino acid sequence shows 34% identity with RANTES. The gene consists of 3 exons and 2 introns with the position of intron/exon boundaries similar to that of RANTES. The gene is expressed as a 3.4-kilobase transcript on lymph node, thymus, and Appendix. STCP-1 induces Ca2+ mobilization in a small percentage of primary activated T lymphocytes, but on repeated stimulation the percentage of T lymphocytes that respond to STCP-1 increases. The chemokine STCP-1 does not induce Ca2+ mobilization in monocytes, dendritic cells, neutrophils, eosinophils, lipopolysaccharide-activated B lymphocytes, and freshly isolated resting T lymphocytes. Similarly, STCP-1, while acting as a mild chemoattractant for primary activated T lymphocytes, is a potent chemoattractant for chronically activated T lymphocytes but has no chemoattractant activity for monocytes, neutrophils, eosinophils, and resting T lymphocytes. As STCP-1 acts specifically on activated T lymphocytes, it may play a role in the trafficking of activated/effector T lymphocytes to inflammatory sites and other aspects of activated T lymphocyte physiology.

IL-20 is expressed in atherosclerosis plaques and promotes atherosclerosis in apolipoprotein E-deficient mice

Objective—Atherosclerosis is a chronic inflammatory disease with immune cell infiltration. Various cytokines and chemokines have been characterized as pro- or antiatherogenic factors. Interleukin-20 (IL-20) belongs to the IL-10 family and is a proinflammatory cytokine involved in the pathogenesis of psoriasis. However, the association between IL-20 and atherosclerosis is undetermined. Therefore, we sought to investigate whether IL-20 is associated with atherosclerosis. Methods and Results—We examined the expression of IL-20 and its receptor complex IL-20R1/IL-20R2 in atherosclerotic lesions of humans and mice using immunohistochemical staining. IL-20 was expressed in macrophage-rich areas. Both IL-20 and IL-20R1/IL-20R2 were expressed by endothelial cells lining the intimal microvessels, vasa vasorum, but rarely in nonatherosclerotic arteries. We used reverse-transcription polymerase chain reaction to analyze gene expression. IL-20 transcripts increased in hypoxic monocytes and monocytes treated with oxidized low-density lipoprotein. The expression of IL-20R1 and IL-20R2 was also upregulated by human umbilical vein endothelial cells in response to hypoxic treatment. Incubating IL-20 with human umbilical vein endothelial cells upregulated CXCL9 and CXCL11 transcripts. Furthermore, in vivo administration of IL-20 expression vector using intramuscular electroporation promoted atherosclerosis in apolipoprotein E-deficient mice. Conclusions—Our data suggest that IL-20 is a proatherogenic cytokine that contributes to the progression of atherosclerosis.

Interleukin-19 upregulates keratinocyte growth factor and is associated with psoriasis

Background  Interleukin (IL)‐19, a member of the IL‐10 family, signals through the IL‐20R1/IL‐20R2 heterodimer, which is shown to be involved in abnormal keratinocyte differentiation and proliferation. Little is known about its in vitro biological functions or its role in psoriasis.

Cloning and characterization of mouse IL-22 binding protein

Interleukin-22 (IL-22), a member of IL-10 family, plays some important roles in immune response through activation of the STAT 3 signal transduction pathway. Two types of IL-22-binding receptor have been discovered, a membrane-bound receptor and a soluble receptor, both encoded by different genes. IL-22 may be involved in inflammatory processes specifically regulated by soluble receptors. By screening a mouse genomic library for a human IL-22 binding protein homologue, we identified the mouse genomic clone of IL-22 binding protein. Its coding sequence was verified and isolated by RT–PCR. The gene encodes a protein of 230 amino acids that share 67.1% amino-acid sequence identity with human IL-22 binding protein. We designated this receptor ‘mouse IL-22 binding protein’ (mIL-22BP). mIL-22BP could be upregulated by LPS stimulation in mouse monocytes. mIL-22BP binds to mouse and human IL-22 and neutralizes STAT3 activation induced by both cytokines in human and rat hepatoma cell lines. Treating B cells with mouse IL-22 induces production of reactive oxygen species, which mIL-22BP blocks.

IL-20 Is regulated by hypoxia-inducible factor and up-regulated after experimental ischemic stroke

IL-20, an IL-10 family member, is involved in various inflammatory diseases, such as psoriasis, rheumatoid arthritis, and atherosclerosis. We investigated whether hypoxia in vitro and an in vivo model of ischemic stroke would up-regulate IL-20 expression. In vitro, IL-20 expression increased in hypoxic HaCaT, HEK293 cells, chondrocytes, monocytes, and glioblastoma cells. Inhibition of hypoxia-inducible factor 1α inhibited CoCl2-induced IL-20 expression. We identified two putative hypoxia response elements in the human il20 gene promoter. Promoter activity assays showed that CoCl2 mimicked hypoxia-activated luciferase reporter gene expression. In vivo, experimental ischemic stroke up-regulated IL-20 in the sera and brain tissue of rats. IL-20 stained positively in glia-like cells in peri-infarcted lesions, but not in contralateral tissue. Administration of IL-20 mAb ameliorated ischemia-induced brain infarction of rats after experimental ischemic stroke. In vitro, RT-PCR analysis showed that glioblastoma cells, GBM8901, expressed IL-20 and its receptor subunits IL-20R1, IL-20R2, and IL-22R1. IL-20 induced cell proliferation in GBM8901 cells by activating the JAK2/STAT3 and ERK1/2 pathways. IL-20 also induced production of IL-1β, IL-8, and MCP-1 in GBM8901 cells. We conclude that IL-20 was responsive to hypoxia in vitro and in the ischemic stroke model and that up-regulation of IL-20 in the ischemic brain may contribute to brain injury.

Anti–IL-20 monoclonal antibody inhibits the differentiation of osteoclasts and protects against osteoporotic bone loss

IL-20 promotes osteoclast differentiation by inducing RANK and RANKL expression in osteoclast precursors and osteoblasts, respectively.