IL-10 subfamily members: IL-19, IL-20, IL-22, IL-24 and IL-26

Hydrodynamic-based delivery of an interleukin-22-Ig fusion gene ameliorates experimental autoimmune myocarditis in rats

IL-22 is one of several cytokines with limited homology to IL-10. However, the biological activities of IL-22 are mostly unknown. The purpose of this study was to evaluate the effect of IL-22 on rat experimental autoimmune myocarditis (EAM) and elucidate an aspect of the biological activities of IL-22. Rats were immunized on day 0; IL-22-Ig-treated rats were injected with pCAGGS-IL-22-Ig and control rats with pCAGGS-Ig using hydrodynamics-based gene delivery on day 1 or day 6. IL-22-Ig gene therapy administered on day 1 or day 6 after immunization was effective in controlling EAM as monitored by the heart weight to body weight ratio, and the myocarditis area in rats was sacrificed on day 17. Examination of the expression of IL-22-related genes in purified cells from EAM hearts suggested that IL-22-Ig acting target cells were noncardiomyocytic (NC) noninflammatory cells such as fibroblasts, smooth muscle cells, and endothelial cells. Therefore, we examined the effect of rIL-22 or serum containing IL-22-Ig on the expression of immune-relevant genes in IL-1-stimulated NC cells cultured from EAM hearts. Results showed that the expression of immunologic molecules (PGE synthase, cyclooxygenase-2, MIP-2, MCP-1, IL-6, and cytokine-induced neutrophil chemoattractant-2) in IL-1-stimulated NC cells was significantly decreased by rIL-22 or serum containing IL-22-Ig. EAM was suppressed by hydrodynamics-based delivery of plasmid DNA encoding IL-22-Ig, and the reason for this effectiveness may be that IL-22 suppressed gene expression of PG synthases, IL-6, and chemokines in activated NC noninflammatory cells.

Tissue microarray analysis of interleukin-20 expression

Knowledge about the biological functions and clinical implications of interleukin (IL)-20, a recently discovered cytokine in the IL-10 family, is still incomplete. Our aim was to determine the distribution of IL-20 expression and to delineate the cell types that express IL-20 in healthy and neoplastic tissue, because this information will significantly affect the exploration of its pathophysiological roles. We used tissue microarray technology and an immunohistochemical survey using an anti-IL-20 monoclonal antibody to examine IL-20 expression in 36 non-neoplastic and 14 neoplastic tissues. IL-20 protein was positively stained in 30 non-neoplastic tissue types and five major cell types: epithelial cells, myoepithelial cells, endothelial cells, macrophages, and skeletal muscle cells. We also found that several types of tumor cells stained positive for IL-20, especially in squamous cell carcinoma of the skin, tongue, esophagus, and lung. Our data provide valuable references for further investigation of the biological functions and clinical implications of IL-20 in humans.

Dynamic and transient remodeling of the macrophage IL-10 promoter during transcription

To gain insight into the molecular mechanism(s) whereby macrophages produce large amounts of IL-10, we analyzed IL-10 gene expression and temporally correlated it with modifications to chromatin associated with the IL-10 promoter. In resting cells, which make essentially no cytokines, the IL-10 promoter is associated with histones containing little or no detectable modifications. Macrophages stimulated in the presence of immune complexes begin to produce high levels of IL-10 pre-mRNA transcripts within minutes of stimulation. Coincident with this transcription was a rapid and dynamic phosphorylation of histone H3 at specific sites in the IL-10 promoter. Histone phosphorylation was closely followed by the binding of transcription factors to the IL-10 promoter. Blocking the activation of ERK prevented histone phosphorylation and transcription factor binding to the IL-10 promoter. In contrast to histone phosphorylation, the peak of histone acetylation at this promoter did not occur until after transcription had peaked. Inhibition of histone deactylase did not alter IL-10 gene expression, suggesting that phosphorylation but not acetylation was the proximal event responsible for IL-10 transcription. Our findings reveal a rapid and well-orchestrated series of events in which ERK activation causes a rapid and transient phosphorylation of histone H3 at specific regions of the IL-10 promoter, resulting in a transient exposure of the IL-10 promoter to the transcription factors that bind there. This exposure is essential for the efficient induction of IL-10 gene expression in macrophages. To our knowledge, this represents a unique way in which the expression of a cytokine gene is regulated in macrophages.

The gene expression profile in refractory periodontitis patients

BACKGROUND

There are no specific bacterial profiles or diagnostic tests capable of identifying refractory periodontitis patients before a treatment regimen is initiated. Therefore, in this high-risk cohort of patients who do not respond appropriately, host factors that might be partly under genetic control may play a crucial role in their susceptibility. Specifically, we tested the hypothesis that patients with refractory periodontitis have multiple upregulated and/or downregulated genes that might be important in influencing clinical risk.

METHODS

Oral subepithelial connective tissues were harvested aseptically from seven refractory periodontitis and seven periodontally well-maintained patients. An RNA isolation kit was used to isolate total RNA from tissue samples that had been stabilized in the RNA stabilizing reagent. The isolated total RNA was then subjected to gene expression profiling using the microarray to measure gene expression levels. The retrieved data were analyzed with a computer program for the differential analysis of gene expression microarray experiments. In addition, real-time polymerase chain reaction (PCR) analysis was performed on selected samples to confirm the microarray data's gene expression patterns.

RESULTS

A total of 68 upregulated and six downregulated genes were identified that were differentially expressed at least two-fold out of 22,283 genes we analyzed. The selected model provided a 93% intrinsic validation along with a 93% extrinsic validation. To validate the microarray data, five upregulated genes (lactotransferrin [LTF], matrix metalloproteinase-1 [MMP-1], MMP-3, interferon induced-15 [IFI-15], and Homo sapiens hypothetical protein MGC5566) and two downregulated genes (keratin 2A [KRT2A] and desmocollin-1 [DSC-1]) were randomly selected for further analysis by real-time PCR. The relative RNA expression level of these genes measured by real-time PCR was similar to those measured by microarrays.

CONCLUSION

The combined use of microarray technology with the computer program for the differential analysis of gene expression microarray experiments provided a set of candidate genes that may serve as novel therapeutic intervention points and improved diagnostic and screening procedures for high-risk individuals.

NF-kappaB1 (p50) homodimers differentially regulate pro- and anti-inflammatory cytokines in macrophages

NF-kappaB/Rel is a family of transcription factors whose activation has long been linked to the production of inflammatory cytokines. Here, we studied NF-kappaB signaling in the regulation of the anti-inflammatory cytokine, interleukin-10 (IL-10). We identified a role for a single NF-kappaB family member, NF-kappaB1 (p50), in promoting the transcription of IL-10. The NF-kappaB ciselement on IL-10 proximal promoter was located to -55/-46, where p50 can homodimerize and form a complex with the transcriptional co-activator CREB-binding protein to activate transcription. The other Rel family members appear to play a negligible role in IL-10 transcription. Mice lacking p50 were more susceptible to lethal endotoxemia, and macrophages taken from p50-/- mice exhibit skewed cytokine responses to lipopolysaccharide, characterized by decreased IL-10 and increased tumor necrosis factor and IL-12. Taken together, our studies demonstrate that NF-kappaB1 (p50) homodimers can be transcriptional activators of IL-10. The reciprocal regulation of pro- and anti-inflammatory cytokine production by NF-kappaB1 (p50) may provide potential new ways to manipulate the innate immune response.

Induction of interleukin-19 and interleukin-22 after cardiac surgery with cardiopulmonary bypass

BACKGROUND

Interleukin (IL)-19, IL-20, and IL-22, three novel cytokines in the IL-10 family, have recently been discovered. The biological functions and clinical implications of these cytokines are not clear. We aimed to analyze if serum levels of these cytokines were altered in inflammatory responses of postoperative cardiopulmonary bypass (CPB) and investigate the molecular mechanism involved in cytokine induction.

METHODS

Twenty-five patients undergoing elective aortic-coronary bypass grafting with CPB were enrolled in this study. Blood samples withdrawn at (T1) before anesthesia, (T2) CPB start, (T3) CPB end, (T4) 4 hours post-CPB, (T5) 8 hours post-CPB, (T6) 12 hours post-CPB, (T7) 24 hours post-CPB, and (T8) 48 hours post-CPB were assayed for IL-6, IL-10, IL-19, IL-20, IL-22, and tumor necrotic factor-alpha (TNF-alpha). Transcripts of IL-19, IL-20, and IL-22 from monocytes were analyzed. In vitro, levels of IL-19, IL-20, and IL-22 production in monocytes incubated with IL-6 and TNF-alpha were determined.

RESULTS

The serum levels of IL-19 and IL-22 significantly increased at T3, peaked at T5, and remained increased at T8 (p<0.001). Induction of IL-19 and IL-22 was concomitant with the change in IL-10, IL-6, and TNF-alpha levels. Interleukin-19, IL-20, and IL-22 transcripts in monocytes from patients increased after CPB. In vitro experiments showed that IL-6 and TNF-alpha upregulated IL-19 protein expression in monocytes.

CONCLUSIONS

Serum IL-19 and IL-22 were induced in cardiac surgery with CPB and concomitant with induction of IL-6 and TNF-alpha. The IL-19 and these proinflammatory cytokines may interactively contribute to systemic inflammatory responses after CPB.

What makes a good anti-inflammatory drug target?

This review focuses on the major, 'successful' target families in inflammation and attempts to identify some of the key features of what makes a good anti-inflammatory target. The review is based on a systematic analysis of approved anti-inflammatory drugs grouped according to their drug-target family. The cytokine family is a drug-dense area. They have yielded and continue to yield a rich stream of drugs. As in other therapeutic areas, G-protein-coupled receptors (GPCRs), also known as seven-transmembrane pass receptors, have provided significant drug targets. In addition, the superfamilies of cell adhesion molecules and co-stimulatory molecules, which have special relevance to immune processes, have begun to provide the first approved drugs and might yield many more. The recent, rapid increase in the number of defined targets in the immune system -- leukocyte surface antigens, cytokines, GPCRs, adhesion molecules and co-stimulatory molecules -- will ensure a rich stream of future anti-inflammatory drug targets.

IL-22 is increased in active Crohn's disease and promotes proinflammatory gene expression and intestinal epithelial cell migration

IL-22 is produced by activated T cells and signals through a receptor complex consisting of IL-22R1 and IL-10R2. The aim of this study was to analyze IL-22 receptor expression, signal transduction, and specific biological functions of this cytokine system in intestinal epithelial cells (IEC). Expression studies were performed by RT-PCR. Signal transduction was analyzed by Western blot experiments, cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and Fas-induced apoptosis by flow cytometry. IEC migration was studied in wounding assays. The IEC lines Caco-2, DLD-1, SW480, HCT116, and HT-29 express both IL-22 receptor subunits IL-22R1 and IL-10R2. Stimulation with TNF-alpha, IL-1beta, and LPS significantly upregulated IL-22R1 without affecting IL-10R2 mRNA expression. IL-22 binding to its receptor complex activates STAT1/3, Akt, ERK1/2, and SAPK/JNK MAP kinases. IL-22 significantly increased cell proliferation (P = 0.002) and phosphatidylinsitol 3-kinase-dependent IEC cell migration (P < 0.00001) as well as mRNA expression of TNF-alpha, IL-8, and human beta-defensin-2. IL-22 had no effect on Fas-induced apoptosis. IL-22 mRNA expression was increased in inflamed colonic lesions of patients with Crohn's disease and correlated highly with the IL-8 expression in these lesions (r = 0.840). Moreover, IL-22 expression was increased in murine dextran sulfate sodium-induced colitis. IEC express functional receptors for IL-22, which increases the expression of proinflammatory cytokines and promotes the innate immune response by increased defensin expression. Moreover, our data indicate intestinal barrier functions for this cytokine-promoting IEC migration, which suggests an important function in intestinal inflammation and wound healing. IL-22 is increased in active Crohn's disease and promotes proinflammatory gene expression and IEC migration.

Neonatal local noxious insult affects gene expression in the spinal dorsal horn of adult rats

Neonatal noxious insult produces a long-term effect on pain processing in adults. Rats subjected to carrageenan (CAR) injection in one hindpaw within the sensitive period develop bilateral hypoalgesia as adults. In the same rats, inflammation of the hindpaw, which was the site of the neonatal injury, induces a localized enhanced hyperalgesia limited to this paw. To gain an insight into the long-term molecular changes involved in the above-described long-term nociceptive effects of neonatal noxious insult at the spinal level, we performed DNA microarray analysis (using microarrays containing oligo-probes for 205 genes encoding receptors and transporters for glutamate, GABA, and amine neurotransmitters, precursors and receptors for neuropeptides, and neurotrophins, cytokines and their receptors) to compare gene expression profiles in the lumbar spinal dorsal horn (LDH) of adult (P60) male rats that received neonatal CAR treatment within (at postnatal day 3; P3) and outside (at postnatal 12; P12) of the sensitive period. The data were obtained both without inflammation (at baseline) and during complete Freund's adjuvant induced inflammation of the neonatally injured paw. The observed changes were verified by real-time RT-PCR. This study revealed significant basal and inflammation-associated aberrations in the expression of multiple genes in the LDH of adult animals receiving CAR injection at P3 as compared to their expression levels in the LDH of animals receiving either no injections or CAR injection at P12. In particular, at baseline, twelve genes (representing GABA, serotonin, adenosine, neuropeptide Y, cholecystokinin, opioid, tachykinin and interleukin systems) were up-regulated in the bilateral LDH of the former animals. The baseline condition in these animals was also characterized by up-regulation of seven genes (encoding members of GABA, cholecystokinin, histamine, serotonin, and neurotensin systems) in the LDH ipsilateral to the neonatally-injured paw. The largest aberration in gene expression, however, was observed during inflammation of the neonatally injured hindpaws in the ipsilateral LDH, which included thirty-six genes (encoding numerous members of glutamate, serotonin, GABA, calcitonin gene-related peptide, neurotrophin, and interleukin systems). These findings suggest that changes in gene expression may be involved in the long-term nociceptive effects of neonatal noxious insult at the spinal level.

Interleukin-22, a member of the IL-10 subfamily, induces inflammatory responses in colonic subepithelial myofibroblasts

BACKGROUND & AIMS

Interleukin (IL)-22, a member of the IL-10 subfamily, is a recently identified T-cell-derived cytokine. We investigated IL-22 expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD) and analyzed its biologic activities in human colonic subepithelial myofibroblasts (SEMFs).

METHODS

Mucosal IL-22 expression was evaluated by immunohistochemical procedures. The effects of IL-22 on colonic SEMFs were investigated by cDNA microarrays, Northern blots, enzyme-linked immunosorbent assay, and electrophoretic gel mobility shift assays (EMSAs).

RESULTS

IL-22 was not detectable in normal colonic mucosa. In IBD mucosa, IL-22 expression was detectable in CD4-positive T cells. IL-22-positive cells were increased in ulcerative colitis and even more so in Crohn's disease. IL-22 receptor expression colocalized with a marker of SEMFs. IL-22 did not modulate SEMF proliferation and collagen synthesis. cDNA microarray analyses demonstrated that, in colonic SEMFs, IL-22 increased the messenger RNA (mRNA) expression of inflammatory cytokines (IL-6, IL-8, IL-11, and leukemia inhibitory factor [LIF]), chemokines, and matrix metalloproteinases. IL-22 induced an activation of nuclear factor (NF)-kappaB and activating protein (AP)-1 within 1 hour, and a blockade of NF-kappaB and AP-1 activation markedly reduced IL-22 induction of IL-6, IL-8, IL-11, and LIF mRNA. MAP-kinase inhibitors (PD98059, U0216, and SB202190) significantly reduced IL-22 induction of cytokine secretion. The combination of either IL-17 plus IL-22 or IL-19 plus IL-22 additively up-regulated cytokine secretion.

CONCLUSIONS

IL-22 derived from activated T cells acts on SEMFs to elicit expression of proinflammatory cytokines and matrix-degrading molecules indicating proinflammatory/remodeling roles in IBD.

Human IL-19 regulates immunity through auto-induction of IL-19 and production of IL-10

IL-19 is a novel, recently identified member of the IL-10 family of cytokines. We identified IL-10 as a cytokine that was strongly induced in IL-19-stimulated PBMC. IL-19-induced IL-10 secretion was dose-dependent and could be detected in culture supernatants after 3 h of stimulation. Furthermore, quantitative RT-PCR analysis demonstrated that IL-19 stimulation increased the level of IL-10 mRNA present within cells, suggesting that IL-19 is a transcriptional activator of IL-10. IL-19 was also able to induce its own expression, with IL-10 potently down-regulating this IL-19 'auto-induction'. LPS induction of IL-19 expression was also regulated by IL-10, demonstrating that IL-10 is likely an important regulator of human IL-19 induction. Maturation of dendritic cells from human PBMC in the presence of IL-19 resulted in an increase in IL-10 levels within these cells, whereas IL-12 was not affected. These results advance our understanding of the function of this novel cytokine and its regulation within the human immune system, in addition to providing a new insight into the control of the important immunoregulatory cytokine, IL-10.

Evolution of the Class 2 cytokines and receptors, and discovery of new friends and relatives

The sequencing of a wide variety of genomes and their transcripts has allowed researchers to determine how proteins or protein families evolved and how strongly during evolution a protein has been conserved. In this report, we analyze the evolution of the Class 2 ligands and their cognate receptors by analyzing Class 2 ligand and receptor chain gene sequences from a variety of DNA sequence databases. Both the Class 2 cytokines and receptor chains appear to have developed during the evolution of the chordate phyla: distant homologues of type I interferon (IFN) receptors are the only Class 2 cytokine receptors identified in the Ciona genomes, while a wide variety of Class 2 ligands and receptor chains are encoded in the currently available genomes of bony vertebrates (teleost fish, amphibians, reptiles, birds, mammals). Phylogenetic trees of ligands and ligand-binding receptor chains demonstrate that proteins involved in conferring antiviral activity diverged before those involved in adaptive immunity. Genes encoding IFNs and IFN receptors duplicated multiple times during chordate evolution, suggesting that duplication of genes encoding IFN activity conveyed an evolutionary advantage. Altogether, these data support a model whereby the original Class 2 cytokines and receptors evolved and duplicated during the evolution of the chordate innate immune response system; new receptor and ligand duplications evolved into signaling molecules to fulfill communication requirements of a highly specialized and differentiated vertebrate immune system. In addition, the genomic analysis led to the discovery of some new members of this family.

Polarized monocyte response to cytokine stimulation

A comprehensive study of the transcriptional response of mononuclear phagocytes to cytokines reveals distinct classes of cytokines that elicit either the classical or alternative pathway of monocyte activation.

Background

Mononuclear phagocytes (MPs) stand at the crossroads between the induction of acute inflammation to recruit and activate immune effector cells and the downmodulation of the inflammatory process to contain collateral damage. This decision is extensively modulated by the cytokine microenvironment, which includes a broad array of cytokines whose direct effect on MPs remains largely unexplored. Therefore, we tested whether polarized responses of MPs to pathogens are related to the influence of selected cytokines or represent a mandatory molecular switch through which most cytokines operate.

Results

Circulating CD14⁺ MPs were exposed to bacterial lipopolysaccharide (LPS) followed by exposure to an array of cytokines, chemokines and soluble factors involved in the immune response. Gene expression was studied by global transcript analysis. Two main classes of cytokines were identified that induced a classical or an alternative pathway of MP activation. Expression of genes affected by NFκB activation was most predictive of the two main classes, suggesting that this pathway is a fundamental target of cytokine regulation. As LPS itself induces a classical type of activation, the most dramatic modulation was observed toward the alternative pathway, suggesting that a broad array of cytokines may counteract the pro-inflammatory effects of bacterial components.

Conclusions

This analysis is directly informative of the primary effect of individual cytokines on the early stages of LPS stimulation and, therefore, may be most informative of the way MP maturation may be polarized at the early stages of the immune response.

Promoter haplotypes of the interleukin-10 gene influence proliferation of peripheral blood cells in response to helminth antigen

Since interleukin (IL)-10 is a key mediator of immunosuppression, and immunosuppression is considered an important element of helminth infection, we studied variants of the putative IL-10 gene promoter in 337 individuals from 130 families heavily exposed to infection by the tissue nematode Onchocerca volvulus. As shown by transmission disequilibrium tests, variants of the IL-10 promoter at positions -1082(G/A), -819(C/T), and -592(C/A) in the haplotype of ATA were significantly associated with high peripheral blood cell (PBC) proliferative responses to O. volvulus antigen (OvAg). No associations were observed using phytohemagglutinin-induced PBC proliferation or with qualitative or quantitative phenotypes of onchocerciasis or onchocerciasis-related skin disease. The findings are compatible with the hypothesis that the ATA haplotype causes a decrease in IL-10 production by OvAg-reactive type-1 regulatory T-lymphocytes, thereby alleviating the suppression of other T cells. To our knowledge, this is the first time that an influence of IL-10 promoter variants is shown on the adaptive immune response.