Pathogenic Interleukin-10 Receptor Alpha Variants in Humans - Balancing Natural Selection and Clinical Implications

Balancing natural selection is a process by which genetic variants arise in populations that are beneficial to heterozygous carriers, but pathogenic when homozygous. We systematically investigated the prevalence, structural, and functional consequences of pathogenic IL10RA variants that are associated with monogenic inflammatory bowel disease. We identify 36 non-synonymous and non-sense variants in the IL10RA gene. Since the majority of these IL10RA variants have not been functionally characterized, we performed a systematic screening of their impact on STAT3 phosphorylation upon IL-10 stimulation. Based on the geographic accumulation of confirmed pathogenic IL10RA variants in East Asia and in Northeast China, the distribution of infectious disorders worldwide, and the functional evidence of IL-10 signaling in the pathogenesis, we identify Schistosoma japonicum infection as plausible selection pressure driving variation in IL10RA. Consistent with this is a partially augmented IL-10 response in peripheral blood mononuclear cells from heterozygous variant carriers. A parasite-driven heterozygote advantage through reduced IL-10 signaling has implications for health care utilization in regions with high allele frequencies and potentially indicates pathogen eradication strategies that target IL-10 signaling.

CCR2 promotes monocyte recruitment and intestinal inflammation in mice lacking the interleukin-10 receptor

Macrophages are a heterogeneous population of mononuclear phagocytes abundantly distributed throughout the intestinal compartments that adapt to microenvironmental specific cues. In adult mice, the majority of intestinal macrophages exhibit a mature phenotype and are derived from blood monocytes. In the steady-state, replenishment of these cells is reduced in the absence of the chemokine receptor CCR2. Within the intestine of mice with colitis, there is a marked increase in the accumulation of immature macrophages that demonstrate an inflammatory phenotype. Here, we asked whether CCR2 is necessary for the development of colitis in mice lacking the receptor for IL10. We compared the development of intestinal inflammation in mice lacking IL10RA or both IL10RA and CCR2. The absence of CCR2 interfered with the accumulation of immature macrophages in IL10R-deficient mice, including a novel population of rounded submucosal Iba1+ cells, and reduced the severity of colitis in these mice. In contrast, the absence of CCR2 did not reduce the augmented inflammatory gene expression observed in mature intestinal macrophages isolated from mice lacking IL10RA. These data suggest that both newly recruited CCR2-dependent immature macrophages and CCR2-independent residual mature macrophages contribute to the development of intestinal inflammation observed in IL10R-deficient mice.

Autosomal recessive 333 base pair interleukin 10 receptor alpha subunit deletion in very early-onset inflammatory bowel disease

BACKGROUND

Interleukin 10 receptor alpha subunit (IL10RA) dysfunction is the main cause of very early-onset inflammatory bowel disease (VEO-IBD) in East Asians.

AIM

To identify disease-causing gene mutations in four patients with VEO-IBD and verify functional changes related to the disease-causing mutations.

METHODS

From May 2016 to September 2020, four young patients with clinically diagnosed VEO-IBD were recruited. Before hospitalization, using targeted gene panel sequencing and trio-whole-exome sequencing (WES), three patients were found to harbor a IL10RA mutation (c.301C>T, p.R101W in one patient; c.537G>A, p.T179T in two patients), but WES results of the fourth patient were not conclusive. We performed whole-genome sequencing (WGS) on patients A and B and reanalyzed the data from patients C and D. Peripheral blood mononuclear cells (PBMCs) from patient D were isolated and stimulated with lipopolysaccharide (LPS), interleukin 10 (IL-10), and LPS + IL-10. Serum IL-10 levels in four patients and tumor necrosis factor-α (TNF-α) in the cell supernatant were determined by enzyme-linked immunosorbent assay. Phosphorylation of signal transducer and activator of transcription 3 (STAT3) at Tyr705 and Ser727 in PBMCs was determined by western blot analysis.

RESULTS

The four children in our study consisted of two males and two females. The age at disease onset ranged from 18 d to 9 mo. After hospitalization, a novel 333-bp deletion encompassing exon 1 of IL10RA was found in patients A and B using WGS and was found in patients C and D after reanalysis of their WES data. Patient D was homozygous for the 333 bp deletion. All four patients had elevated serum IL-10 levels. In vitro, IL-10-stimulated PBMCs from patient D failed to induce STAT3 phosphorylation at Tyr705 and only minimally suppressed TNF-α production induced by LPS. Phosphorylation at Ser727 in PBMCs was not affected by LPS or LPS + IL-10 in both healthy subjects and in patient D.

CONCLUSION

WGS revealed a novel 333-bp deletion of IL10RA in four patients with VEO-IBD, whereas the WES results were inconclusive.

Importance of early detection of infantile inflammatory bowel disease with defective IL-10 pathway: A case report

RATIONALE

Infantile inflammatory bowel disease (IBD) is an extremely rare subgroup of IBD that includes patients whose age of onset is younger than 2 years old. These patients can have more surgical interventions, and a severe and refractory disease course with higher rates of conventional treatment failure. Monogenic defects play an important role in this subgroup of IBD, and identification of the underlying defect can guide the therapeutic approach.

PATIENT CONCERNS

In 2007, a 4-month-old girl from a nonconsanguineous family presenting with anal fistula, chronic diarrhea, and failure to thrive. She underwent multiple surgical repairs but continued to have persistent colitis and perianal fistulas.

DIAGNOSIS

Crohn's disease was confirmed by endoscopic and histologic finding.

INTERVENTION

Conventional pediatric IBD therapy including multiple surgical interventions and antitumor necrosis factor alpha agents were applied.

OUTCOMES

The patient did not respond to conventional pediatric IBD therapy. Interleukin-10 (IL-10) receptor mutation was discovered by whole-exome sequencing and defective IL-10 signaling was proved by functional test of IL-10 signaling pathway by the age of 12. The patient is currently awaiting hematopoietic stem cell transplantation.

LESSONS

Early detection of underlying genetic causes of patients with infantile-IBD is crucial, since it may prevent patients from undergoing unnecessary surgeries and adverse effects from ineffective medical therapies. Moreover, infantile-IBD patients with complex perianal disease, intractable early onset enterocolitis and extraintestinal manifestations including oral ulcers and skin folliculitis, should undergo genetic and functional testing for IL-10 pathway defect.

Tongue sole (Cynoglossus semilaevis) interleukin 10 receptors are involved in the immune response against bacterial infection

Interleukin (IL)-10, an immune-regulatory cytokine, exerts various biological functions through interaction with IL-10 receptors. In teleost, very limited functional studies on IL-10 receptors have been documented. In this study, we reported the expression patterns of IL-10 receptor 1 (CsIL-10R1) and receptor 2 (CsIL-10R2) of tongue sole (Cynoglossus semilaevis) and examined their biological properties. The expression of CsIL-10R1 and CsIL-10R2 occurred in multiple tissues and were regulated by bacterial challenge. In vitro binding studies showed that recombinant extracellular region of CsIL-10R1 (rCsIL-10R1ex) rather than rCsIL-10R2ex could bind with rCsIL-10. Cellular study showed that both CsIL-10R1 and CsIL-10R2 were expressed on peripheral blood leukocytes (PBLs), and blockade of CsIL-10R1 or CsIL-10R2 by antibody could reduce inhibitory effect of CsIL-10 on ROS production of PBLs. When injected in vivo, anti-rCsIL-10R1 or anti-rCsIL-10R2 antibody dramatically promoted the expression of proinflammatory cytokines and suppressed bacterial dissemination in tongue sole tissues. Consistently, the overexpression of CsIL-10R1 or CsIL-10R2 significantly enhanced bacterial dissemination, and the overexpression of CsIL-10R1M bearing STAT3 site mutation reduced bacterial dissemination. Overall, these results demonstrate for the first time teleost IL-10 receptors play a negative role in antibacterial immunity and add insight into the function of CsIL-10 receptors.

Functional characterization of IL-10 and its receptor subunits in a perciform fish, the mandarin fish, Siniperca chuatsi

Interleukin (IL)-10 is an immune-regulatory cytokine with multiple functions. In the current study, IL-10 and its two receptors, IL-10R1 and IL-10R2 were identified in mandarin fish, Siniperca chuatsi. The inhibitory effect of mandarin fish IL-10 was investigated on pro-inflammatory cytokine expression and the ligand-receptor relationship. This IL-10 possesses conserved cysteine residues, predicted α-helices and a typical IL-10 family signature motif, similar to its mammalian orthologue, and IL-10R1 harbours predicted JAK1 and STAT3 binding sites in the intracellular region. The fish IL-10 and IL-10R1 exhibit high expression levels in several immune-related organs/tissues, such as spleen, trunk kidney and head kidney, and IL-10R2 possesses a constitutive expression pattern. The expression of IL-10 shows significant increase in spleen from infectious spleen and kidney necrosis virus (ISKNV) infected mandarin fish, where the two receptors also exhibit different levels of induced expression. Mandarin fish IL-10 also exhibits significant response to the stimulation of LPS, PHA and PMA, with the two receptors exhibiting an interesting decrease in expression following the treatment of PMA. The pro-inflammatory cytokines, IL-6, IL-1β, IL-8, TNF-α, show diminished up-regulation in LPS-stimulated splenocytes pre-incubated with IL-10, indicating the anti-inflammatory roles of mandarin fish IL-10. In EPC cells transfected with different combinations of receptors, IL-10 can enhance the expression of suppressor of cytokine signalling 3 (SOCS3) only when IL-10R1 and IL-10R2 are both expressed, suggesting the participation of the two receptors in signal transduction of mandarin fish IL-10. Similar results are observed with the usage of chimeric receptors, IL-10R1/CRFB1 and IL-10R2/CRFB5. Overall, mandarin fish IL-10 shares conserved ligand-receptor system and the prototypical inhibitory activities on pro-inflammatory cytokine expression with mammalian IL-10, implying the evolutionary conservation of this cytokine.

[Clinical and genotypic characteristics of infantile inflammatory bowel disease]

Objective: To analyze the clinical and genotypic characteristics of infantile inflammatory bowel disease (IBD). Methods: The age of onset, family history, clinical manifestations, and treatment effect were retrospectively analyzed in 39 infants (male 23 cases, female 16 cases) with IBD who were admitted to the Department of Gastroenterology in Children's Hospital, Capital Institute of Pediatrics from January 2007 to December 2017. Next generation sequencing (NGS) based on target gene panel was used for gene analysis in 17 patients. Results: The median age of onset was 0.5 (0.5, 1.0) month. The most common clinical symptoms included diarrhea (39, 100%), malnutrition (38, 97%), hematochezia (34, 87%), fever (25, 64%), and perianal diseases (24, 61%). Four children had associated family history. Among the 17 patients whose gene was analyzed, 10 were found to have the pathogenic gene variation, within whom 7 had interleukin-10 receptor α subunit (IL-10RA) mutation, 2 had CYBB heterozygous mutation, 1 had interleukin-10 receptor β subunit (IL-10RB) mutation. The therapeutic medicine included mesalazine, steroids, and thalidomide. Eighteen children (46%) reached clinical remission (10 cases) or partial remission (8 cases). Conclusions: The incidence of single gene mutation in infants with IBD is high, with IL-10RA mutation as the most common. Refractory diarrhea and malnutrition may indicate infantile IBD.

Association of IL-10 and IL-10RA single nucleotide polymorphisms with the responsiveness to HBV vaccination in Chinese infants of HBsAg(+)/HBeAg(-) mothers: a nested case-control study

OBJECTIVES

To investigate the association of interleukin (IL)-10 and IL-10 receptor A (IL-10RA) single nucleotide polymorphisms with the responsiveness to hepatitis B virus (HBV) vaccination in newborns whose mothers were hepatitis B surface antigen (HBsAg)(+)/hepatitis B e antigen (HBeAg)(-).

DESIGN

Nested case-control study.

SETTING

Changchun, China.

PARTICIPANTS

713 infants from a Han Chinese population whose mothers were HBsAg(+)/HBeAg(-) and participated in the prevention of mother-to-child transmission of HBV at the First Hospital of Jilin University from July 2012 to July 2015 were included. Infants were excluded for HBsAg-positive; unstandardised vaccination process; inadequate blood samples; not Han Chinese and failed genotyping.

RESULTS

Infants with artificial feeding pattern were correlated with low responsiveness to HBV vaccination (p=0.009). The GG genotype of IL-10 rs3021094 was correlated with a higher risk of low responsiveness to HBV vaccination (OR 2.80, 95% CI 1.35 to 5.83). No haplotype was found to be correlated with responsiveness to HBV vaccination. No gene-gene interaction was found between IL-10 and IL-10RA.

CONCLUSIONS

Our study found that IL-10 gene variants were significantly associated with the immune response to the HBV vaccine. Identifying these high-risk infants who born to HBsAg(+)/HBeAg(-) mothers and low responses to hepatitis B vaccination will provide evidence for individualised prevention strategies.

Genetic association and epistatic interaction of the interleukin-10 signaling pathway in pediatric inflammatory bowel disease

AIM

To study the genetic association and epistatic interaction of the interleukin (IL)-10 and IL-10/STAT3 pathways in pediatric inflammatory bowel disease (IBD).

METHODS

A total of 159 pediatric inflammatory IBD patients (Crohn’s disease, n = 136; ulcerative colitis, n = 23) and 129 matched controls were studied for genetic association of selected single nucleotide polymorphisms (SNPs) of the IL-10 gene and the genes IL10RA, IL10RB, STAT3, and HO1, from the IL-10/STAT3 signaling pathway. As interactions between SNPs from different loci may significantly affect the associated risk for disease, additive (a) and dominant (d) modeling of SNP interactions was also performed to examine high-order epistasis between combinations of the individual SNPs.

RESULTS

The results showed that IL-10 rs304496 was associated with pediatric IBD (P = 0.022), but no association was found for two other IL-10 SNPs, rs1800872 and rs2034498, or for SNPs in genes IL10RA, IL10RB, STAT3, and HO1. However, analysis of epistatic interaction among these genes showed significant interactions: (1) between two IL-10 SNPs rs1800872 and rs3024496 (additive-additive P = 0.00015, Bonferroni P value (Bp) = 0.003); (2) between IL-10RB rs2834167 and HO1 rs2071746 (dominant-additive, P = 0.0018, Bp = 0.039); and (3) among IL-10 rs1800872, IL10RB rs2834167, and HO1 rs2071746 (additive-dominant-additive, P = 0.00015, Bp = 0.005), as well as weak interactions among IL-10 rs1800872, IL-10 rs3024496, and IL-10RA (additive-additive-additive, P = 0.003; Bp = 0.099), and among IL10RA, IL10RB, and HO1 genes (additive-dominant-additive, P = 0.008, Bp = 0.287).

CONCLUSION

These results indicate that both the IL-10 gene itself, and through epistatic interaction with genes within the IL-10/STAT3 signaling pathway, contribute to the risk of pediatric IBD.

Systematic analysis of chromatin interactions at disease associated loci links novel candidate genes to inflammatory bowel disease

BACKGROUND

Genome-wide association studies (GWAS) have revealed many susceptibility loci for complex genetic diseases. For most loci, the causal genes have not been identified. Currently, the identification of candidate genes is predominantly based on genes that localize close to or within identified loci. We have recently shown that 92 of the 163 inflammatory bowel disease (IBD)-loci co-localize with non-coding DNA regulatory elements (DREs). Mutations in DREs can contribute to IBD pathogenesis through dysregulation of gene expression. Consequently, genes that are regulated by these 92 DREs are to be considered as candidate genes. This study uses circular chromosome conformation capture-sequencing (4C-seq) to systematically analyze chromatin-interactions at IBD susceptibility loci that localize to regulatory DNA.

RESULTS

Using 4C-seq, we identify genomic regions that physically interact with the 92 DRE that were found at IBD susceptibility loci. Since the activity of regulatory elements is cell-type specific, 4C-seq was performed in monocytes, lymphocytes, and intestinal epithelial cells. Altogether, we identified 902 novel IBD candidate genes. These include genes specific for IBD-subtypes and many noteworthy genes including ATG9A and IL10RA. We show that expression of many novel candidate genes is genotype-dependent and that these genes are upregulated during intestinal inflammation in IBD. Furthermore, we identify HNF4α as a potential key upstream regulator of IBD candidate genes.

CONCLUSIONS

We reveal many novel and relevant IBD candidate genes, pathways, and regulators. Our approach complements classical candidate gene identification, links novel genes to IBD and can be applied to any existing GWAS data.

Synthetic Lethal Screen Demonstrates That a JAK2 Inhibitor Suppresses a BCL6-dependent IL10RA/JAK2/STAT3 Pathway in High Grade B-cell Lymphoma

We demonstrate the usefulness of synthetic lethal screening of a conditionally BCL6-deficient Burkitt lymphoma cell line, DG75-AB7, with a library of small molecules to determine survival pathways suppressed by BCL6 and suggest mechanism-based treatments for lymphoma. Lestaurtinib, a JAK2 inhibitor and one of the hits from the screen, repressed survival of BCL6-deficient cells in vitro and reduced growth and proliferation of xenografts in vivo BCL6 deficiency in DG75-AB7 induced JAK2 mRNA and protein expression and STAT3 phosphorylation. Surface IL10RA was elevated by BCL6 deficiency, and blockade of IL10RA repressed STAT3 phosphorylation. Therefore, we define an IL10RA/JAK2/STAT3 pathway each component of which is repressed by BCL6. We also show for the first time that JAK2 is a direct BCL6 target gene; BCL6 bound to the JAK2 promoter in vitro and was enriched by ChIP-seq. The place of JAK2 inhibitors in the treatment of diffuse large B-cell lymphoma has not been defined; we suggest that JAK2 inhibitors might be most effective in poor prognosis ABC-DLBCL, which shows higher levels of IL10RA, JAK2, and STAT3 but lower levels of BCL6 than GC-DLBCL and might be usefully combined with novel approaches such as inhibition of IL10RA.

Comprehensive mutation screening for 10 genes in Chinese patients suffering very early onset inflammatory bowel disease

AIM

To perform sequencing analysis in patients with very early-onset inflammatory bowel disease (VEO-IBD) to determine the genetic basis for VEO-IBD in Chinese pediatric patients.

METHODS

A total of 13 Chinese pediatric patients with VEO-IBD were diagnosed from May 2012 and August 2014. The relevant clinical characteristics of these patients were analyzed. Then DNA in the peripheral blood from patients was extracted. Next generation sequencing (NGS) based on an Illumina-Miseq platform was used to analyze the exons in the coding regions of 10 candidate genes: IL-10, IL-10RA, IL-10RB, NOD2, FUT2, IL23R, GPR35, GPR65, TNFSF15, and ADAM30. The Sanger sequencing was used to verify the variations detected in NGS.

RESULTS

Out of the 13 pediatric patients, ten were diagnosed with Crohn's disease, and three diagnosed with ulcerative colitis. Mutations in IL-10RA and IL-10RB were detected in five patients. There were four patients who had single nucleotide polymorphisms associated with IBD. Two patients had IL-10RA and FUT2 polymorphisms, and two patients had IL-10RB and FUT2 polymorphisms. Gene variations were not found in the rest four patients. Children with mutations had lower percentile body weight (1.0% vs 27.5%, P = 0.002) and hemoglobin (87.4 g/L vs 108.5 g/L, P = 0.040) when compared with children without mutations. Although the age of onset was earlier, height was shorter, and the response to treatment was poorer in the mutation group, there was no significant difference in these factors between groups.

CONCLUSION

IL-10RA and IL-10RB mutations are common in Chinese children with VEO-IBD. Patients with mutations have an earlier disease onset, lower body weight and hemoglobin, and poorer prognosis.

Monogenic autoinflammatory diseases: Cytokinopathies

Rapid advances in genetics are providing unprecedented insight into functions of the innate immune system with identification of the mutations that cause monogenic autoinflammatory disease. Cytokine antagonism is profoundly effective in a subset of these conditions, particularly those associated with increased interleukin-1 (IL-1) activity, the inflammasomopathies. These include syndromes where the production of IL-1 is increased by mutation of innate immune sensors such as NLRP3, upstream signalling molecules such as PSTPIP1 and receptors or downstream signalling molecules, such as IL-1Ra. Another example of this is interferon (IFN) and the interferonopathies, with mutations in the sensors STING and MDA5, the upstream signalling regulator AP1S3, and a downstream inhibitor of IFN signalling, ISG15. We propose that this can be extended to cytokines such as IL-36, with mutations in IL-36Ra, and IL-10, with mutations in IL-10RA and IL-10RB, however mutations in sensors or upstream signalling molecules are yet to be described in these instances. Additionally, autoinflammatory diseases can be caused by multiple cytokines, for example with the activation of NF-κB/Rel, for which we propose the term Relopathies. This nosology is limited in that some cytokine pathways may be degenerate in their generation or execution, however provides insight into likely autoinflammatory disease candidates and the cytokines with which newly identified mutations may be associated, and therefore targeted.

Novel missense mutation in the NOD2 gene in a patient with early onset ulcerative colitis: causal or chance association?

Deregulated immune response to gut microflora in genetically predisposed individuals is typical for inflammatory bowel diseases. It is reasonable to assume that genetic association with the disease will be more pronounced in subjects with early onset than adult onset. The nucleotide-binding oligomerization domain containing-2 gene, commonly involved in multifactorial risk of Crohn’s disease, and interleukin 10 receptor genes, associated with rare forms of early onset inflammatory bowel diseases, were sequenced in an early onset patient. We identified a novel variant in the NOD2 gene (c.2857A > G p.K953E) and two already described missense variants in the IL10RA gene (S159G and G351R). The new NOD2 missense variant was examined in silico with two online bioinformatics tools to predict the potentially deleterious effects of the mutation. Although cumulative effect of these variations in the early onset of the disease can be only hypothesized, we demonstrated that family information and in silico studies can be used to predict association with the disease.

Synergistic effect of interleukin-10-receptor variants in a case of early-onset ulcerative colitis

AIM: To investigated the molecular cause of very early-onset ulcerative colitis (UC) in an 18-mo-old affected child.

METHODS: We analysed the interleukin-10 (IL10) receptor genes at the DNA and RNA level in the proband and his relatives. Beta catenin and tumor necrosis factor-α (TNFα) receptors were analysed in the proteins extracted from peripheral blood cells of the proband, his relatives and familial adenomatous polyposis (FAP) and PTEN hamartoma tumor syndrome (PHTS) patients. Samples were also collected from the proband’s inflamed colorectal mucosa and compared to healthy and tumour mucosa collected from a FAP patient and patients affected by sporadic colorectal cancer (CRC). Finally, we examined mesalazine and azathioprine effects on primary fibroblasts stabilised from UC and FAP patients.

RESULTS: Our patient was a compound heterozygote for the IL10RB E47K polymorphism, inherited from his father, and for a novel point mutation within the IL10RA promoter (the -413G->T), inherited from his mother. Beta catenin and tumour necrosis factor α receptors-I (TNFRI) protein were both over-expressed in peripheral blood cells of the proband’s relatives more than the proband. However, TNFRII was over-expressed only in the proband. Finally, both TNFα-receptors were shown to be under-expressed in the inflamed colon mucosa and colorectal cancer tissue compared to healthy colon mucosa. Consistent with this observation, mesalazine and azathioprine induced, in primary fibroblasts, IL10RB and TNFRII over-expression and TNFRI and TNFα under-expression. We suggest that β-catenin and TNFRI protein expression in peripheral blood cells could represent molecular markers of sub-clinical disease in apparently healthy relatives of patients with early-onset UC.

CONCLUSION: A synergistic effect of several variant alleles of the IL10 receptor genes, inherited in a Mendelian manner, is involved in UC onset in this young child.

IL-27 receptor signalling restricts the formation of pathogenic, terminally differentiated Th1 cells during malaria infection by repressing IL-12 dependent signals

The IL-27R, WSX-1, is required to limit IFN-γ production by effector CD4⁺ T cells in a number of different inflammatory conditions but the molecular basis of WSX-1-mediated regulation of Th1 responses in vivo during infection has not been investigated in detail. In this study we demonstrate that WSX-1 signalling suppresses the development of pathogenic, terminally differentiated (KLRG-1⁺) Th1 cells during malaria infection and establishes a restrictive threshold to constrain the emergent Th1 response. Importantly, we show that WSX-1 regulates cell-intrinsic responsiveness to IL-12 and IL-2, but the fate of the effector CD4⁺ T cell pool during malaria infection is controlled primarily through IL-12 dependent signals. Finally, we show that WSX-1 regulates Th1 cell terminal differentiation during malaria infection through IL-10 and Foxp3 independent mechanisms; the kinetics and magnitude of the Th1 response, and the degree of Th1 cell terminal differentiation, were comparable in WT, IL-10R1^−/− and IL-10^−/− mice and the numbers and phenotype of Foxp3⁺ cells were largely unaltered in WSX-1^−/− mice during infection. As expected, depletion of Foxp3⁺ cells did not enhance Th1 cell polarisation or terminal differentiation during malaria infection. Our results significantly expand our understanding of how IL-27 regulates Th1 responses in vivo during inflammatory conditions and establishes WSX-1 as a critical and non-redundant regulator of the emergent Th1 effector response during malaria infection.

The cytokine interleukin 27 (IL-27), a member of the IL-12 family, is produced by cells of the innate immune system and has been shown to exert mainly suppressive effects during a wide range of inflammatory conditions, including malaria infection, where it suppresses the development of CD4⁺ T cell-dependent immunopathology. In this study we show that IL-27 suppresses the production of IFN-gamma by CD4⁺ T cells during blood stage malaria infection by preventing the development of terminally differentiated Th1 cells. We investigated the molecular mechanisms by which IL-27 inhibits the formation of terminally differentiated Th1 cells and found that it does so specifically by restricting IL-12 signals. Importantly, we demonstrate that IL-27 mediates its regulatory effects on the Th1 response through IL-10 and Foxp3⁺ regulatory T cell independent mechanisms. Thus, we have identified a new pathway though which IL-27 signalling regulates the size and quality of the Th1 response during malaria infection, which we believe will have relevance to many other pro-inflammatory conditions. Manipulation of the IL-27 pathway may therefore represent an amenable therapeutic approach during chronic inflammatory disorders.

Association between IL10, IL10RA, and IL10RB SNPs and ischemic stroke with hypertension in Korean population

The pathogenesis of stroke is associated with the immune and inflammatory responses. Cytokines, such as interleukin 10 (IL10), play an important role in the process of inflammation. To investigate whether IL10, IL10RA, and IL10RB polymorphisms are associated with the risk of ischemic stroke (IS), selected two IL10 SNPs (rs1518111 and rs1554286), three IL10RA SNPs (rs2256111, rs4252243, and rs2228054), and two IL10RB SNPs (rs999788 and rs2834167) were analyzed in 120 patients with IS and 285 control subjects. All IS patients were classified into the clinical subgroups, according to the levels of blood pressure (hypertension, present and absent), fasting plasma glucose (diabetes mellitus, present and absent), and lipids (dyslipidemia, present and absent). SNPStats and SPSS 18.0 program were used to obtain the odds ratios, 95 % confidence intervals, and P values. Multiple logistic regression models (codominant1, codominant2, dominant, recessive, and log-additive models) were performed to analyze the genetic data. Seven polymorphisms were not associated with the IS, but showed significant associations with hypertension, in the risk of IS. These results suggest that the IL10, IL10RA, and IL10RB genes may be contributed to the hypertension in the risk of IS in the Korean population.

Type I and III interferons enhance IL-10R expression on human monocytes and macrophages, resulting in IL-10-mediated suppression of TLR-induced IL-12

Currently, only about 30-50% of chronic hepatitis C virus (HCV) and hepatitis B virus (HBV) patients respond to IFN-based therapy. It has been suggested that IL-10 is involved in suppressing the activity of type I IFNs on antigen-presenting cells (APCs). However, the interaction between type I IFNs and IL-10 is still not clear. Here we report that IFN-α priming upregulated the expression of IL-10R1 on monocytes, and subsequently IL-10 induced a higher level of STAT3 phosphorylation in IFN-primed cells. This indicates that IFN-α increased the sensitivity of monocytes to IL-10, and as a result, TLR-induced IL-12p70 by IFN-pretreated cells was suppressed. Interestingly, both IFN-β and IL-29, a member of the type III IFN family, comparably sensitized monocytes and macrophages to IL-10 stimulation, indicating a general effect of IFN on the activity of IL-10 in APCs. In summary, we demonstrate that one of the consequences of priming human APCs with IFN is to promote the cells' sensitivity to IL-10, which leads to the inhibition of TLR-induced IL-12p70 production. Therefore, type I and III IFNs induce a suboptimal activation of immune cells. These findings are relevant for the development of strategies to further improve IFN-based therapy for patients with multiple sclerosis or viral hepatitis.

Genetic polymorphisms in IL10RA and TNF modify the association between blood transfusion and risk of non-Hodgkin lymphoma

We conducted a population-based case-control study in Connecticut women to test the hypothesis that genetic variations in Th1 and Th2 cytokine genes may modify the association between blood transfusion and risk of non-Hodgkin lymphoma (NHL). Compared with women without blood transfusion, women with a history of transfusion had an increased risk of NHL if they carried IL10RA (rs9610) GG genotype [odds ratio (OR) = 1.9, 95% confidence interval (CI): 1.1-3.2] or TNF (rs1800629) AG/AA genotypes (OR = 1.6, 95% CI: 0.9-2.7). We also found women with a history of transfusion had a decreased risk of NHL if they carried IL10RA (rs9610) AG/AA genotypes (OR = 0.6, 95% CI: 0.4-0.9) or TNF (rs1800629) GG genotype (OR = 0.7, 95% CI: 0.5-1.0). A similar pattern was also observed for B-cell lymphoma but not for T-cell lymphoma. Statistically significant interactions with blood transfusion were observed for IL10RA (rs9610) (P(forinteraction) = 0.003) and TNF (rs1800629) (P(forinteraction) = 0.012) for NHL overall and IL10RA (rs9610) (P(forinteraction) = 0.001) and TNF (rs1800629) (P(forinteraction) = 0.019) for B-cell lymphoma. The results suggest that genetic polymorphisms in TNF and IL10RA genes may modify the association between blood transfusion and NHL risk.

Identification and molecular characterization of the interleukin-10 receptor 1 of the zebrafish (Danio rerio) and the goldfish (Carassius auratus L.)

This is the first report of the identification and molecular characterization of an interleukin-10 receptor 1 in bony fish. By gene synteny analysis, we identified the zebrafish interleukin-10 receptor 1 (IL10R1) and using this IL10R1 sequence, we cloned the goldfish IL10R1 cDNA transcript. The identified fish IL10R1 protein sequences had a putative JAK1 binding site, only one of the two STAT3 binding sites, that are present in all other vertebrates IL10R1 proteins as well as C-terminal serine rich areas, believed to be responsible for the anti-inflammatory properties of IL10R1. Phylogenetically, the fish IL10R1 proteins grouped independently of the amphibian, avian and mammalian IL10R1s. Quantitative gene expression analysis of the IL10R1 of zebrafish and goldfish revealed highest mRNA levels in the spleen tissues. High mRNA levels were also observed in the zebrafish muscle in contrast to low mRNA levels in the muscle of the goldfish. Moderate IL10R1 mRNA levels were seen in most other tissues examined and lowest gene expression was in the liver of both fish species. Goldfish monocytes stimulated with a recombinant goldfish interleukin-10 (rgIL-10) or with heat killed fish pathogens, Aeromonas salmonicida or Trypanosoma carassii, exhibited significantly reduced mRNA levels of the IL10R1. Furthermore, we produced a recombinant form of the goldfish IL10R1 (rgIL10R1) and using in vitro binding studies, demonstrated that the dimerized rgIL-10 specifically interacted with rgIL10R1. Our results suggest that interleukin-10 system has been highly conserved throughout evolution.

IL-10 elicits IFNγ-dependent tumor immune surveillance

Tumor immune surveillance and cancer immunotherapies are thought to depend on the intratumoral infiltration of activated CD8(+) T cells. Intratumoral CD8(+) T cells are rare and lack activity. IL-10 is thought to contribute to the underlying immune suppressive microenvironment. Defying those expectations we demonstrate that IL-10 induces several essential mechanisms for effective antitumor immune surveillance: infiltration and activation of intratumoral tumor-specific cytotoxic CD8(+) T cells, expression of the Th1 cytokine interferon-γ (IFNγ) and granzymes in CD8(+) T cells, and intratumoral antigen presentation molecules. Consequently, tumor immune surveillance is weakened in mice deficient for IL-10 whereas transgenic overexpression of IL-10 protects mice from carcinogenesis. Treatment with pegylated IL-10 restores tumor-specific intratumoral CD8(+) T cell function and controls tumor growth.

Association of IL10, IL10RA, and IL10RB polymorphisms with benign prostate hyperplasia in Korean population

Cytokines such as interleukin 10 (IL10) may play an important role in the process of inflammation. The aim of this study was to analyze the association between IL10, IL10RA and IL10RB single nucleotide polymorphisms (SNPs), and benign prostate hyperplasia (BPH) in Korean population. All patients with BPH were divided into two groups according to international prostate symptom score (IPSS), prostate specific antigen (PSA) level, Q(max), and prostate volume. We selected two IL10 SNPs (rs1518111 and rs1554286), three IL10RA SNPs (rs2256111, rs4252243, and rs2228054), and two IL10RB SNPs (rs999788 and rs2834167). Genotypes of seven SNPs were determined through direct sequencing. The G/G genotype of IL10RB polymorphism (rs2834167) was associated with a high PSA level compared with the A/G + A/A genotypes (P = 0.009). Of IL10 SNP, the A/A genotype of rs1518111 and T/T genotype of rs1554286 were associated with small prostate volume, respectively (P = 0.011, P = 0.014). Moreover, the T/T genotype of IL10RB polymorphism (rs999788) was associated with high prostatic volume compared with the T/C + C/C genotypes (P = 0.033). The linkage disequilibrium (LD) blocks were formed in IL10 and IL10RA. However, haplotypes in the LD block were not associated with BPH. It is concluded that there is a strong association between the IL10 and IL10RB SNPs, and BPH in Korean population.

Inflammatory bowel disease and mutations affecting the interleukin-10 receptor

BACKGROUND

The molecular cause of inflammatory bowel disease is largely unknown.

METHODS

We performed genetic-linkage analysis and candidate-gene sequencing on samples from two unrelated consanguineous families with children who were affected by early-onset inflammatory bowel disease. We screened six additional patients with early-onset colitis for mutations in two candidate genes and carried out functional assays in patients' peripheral-blood mononuclear cells. We performed an allogeneic hematopoietic stem-cell transplantation in one patient.

RESULTS

In four of nine patients with early-onset colitis, we identified three distinct homozygous mutations in genes IL10RA and IL10RB, encoding the IL10R1 and IL10R2 proteins, respectively, which form a heterotetramer to make up the interleukin-10 receptor. The mutations abrogate interleukin-10-induced signaling, as shown by deficient STAT3 (signal transducer and activator of transcription 3) phosphorylation on stimulation with interleukin-10. Consistent with this observation was the increased secretion of tumor necrosis factor alpha and other proinflammatory cytokines from peripheral-blood mononuclear cells from patients who were deficient in IL10R subunit proteins, suggesting that interleukin-10-dependent "negative feedback" regulation is disrupted in these cells. The allogeneic stem-cell transplantation performed in one patient was successful.

CONCLUSIONS

Mutations in genes encoding the IL10R subunit proteins were found in patients with early-onset enterocolitis, involving hyperinflammatory immune responses in the intestine. Allogeneic stem-cell transplantation resulted in disease remission in one patient.

Human interleukin 10 receptor 1/IgG1-Fc fusion proteins: immunoadhesins for human IL-10 with therapeutic potential

Interleukin 10 (IL-10) is produced by various types of human cancer, including malignant melanoma, and plays an important role in negative regulation of cell-mediated immune responses against tumors. We have developed chimeric molecules (immunoadhesins), combining the extracellular domain of human interleukin 10 receptor 1 (IL-10R1) with the Fc regions of human IgG1 heavy chain and investigated their capability of blocking the biological activities of human IL-10. Monomeric and dimeric immunoadhesins (IL-10R1/IgG1) constructs were tested for capturing human IL-10 and blocking its biological activities. Plasmid vectors that contained the IL-10 immunoadhesin constructs were directly transfected into human melanoma cell lines. Transfection of plasmid vectors into melanoma cell lines resulted in capturing of exogenously added as well as endogeneously produced IL-10. The supernatants obtained from an IL-10 non-producing melanoma cell line transfected with monomeric IL-10 immunoadhesin plasmids most efficiently captured exogenously added IL-10, compared to those obtained with the dimeric IL-10R1/IgG1 plasmid vector. Transfection of IL-10-producing melanoma cells with the monomeric IL-10 immunoadhesin plasmids totally captured endogenously produced IL-10 and enhanced T cell responses against allogeneic melanoma cells. Furthermore, purified monomeric IL-10 immunoadhesin protein showed IL-10 capturing efficacy compatible with that of IL-10-specific monoclonal antibodies. Collectively, these studies indicate that IL-10 immunoadhesins, especially in monomeric form, are potent inhibitors of biological activities of IL-10 and suggest that these molecules, alone or in conjunctions with other immunotherapeutic approaches, can be utilized for the immuno-targeting of IL-10 producing tumors.

[The effect of IL-10 on proliferation of primary cultured hepatocytes]

AIM

To investigate the effect of IL-10 on proliferation of rat primary cultured hepatocytes.

METHODS

Rat hepatocytes were isolated from rat liver by in situ digestion of collagenase IV and cryopreserved, resuscitated, cultured in vitro. Reverse-transcription polymerase chain reaction (RT-PCR) was used to characterize the purity of hepatocytes and analyze IL-10/IL10Ralpha mRNA from freshly isolated cells. The primary cultured hepatocytes were divided into 3 groups and treated with nothing (group N), Insulin (group C), and IL-10 in combination with Insulin (group I), respectively. Nuclear cell cycle analysis, MTT, and Trypan Blue cell count was assayed.

RESULTS

RT-PCR showed expression of characterization genes in primary hepatocytes group and liver tissue are different. RT-PCR showed an expression of IL-10/IL10Ralpha mRNA in rat primary hepatocytes. Trypan Blue cell count showed an depression of cell quantity in group I at 48h (71.96% contrast to group C, P<0.05). MTT analyse also showed absorbance of group I was declined contrast to group C at 24 h and 48 h (88.41% and 90.24%, P<0.05). Cell cycle analysis via FCM showed a decline at 24h in group I than group C and group N (59.06% and 70.18%, P<0.01).

CONCLUSION

The primary hepatocytes we isolated is quite purity. Rat primary hepatocytes express IL-10/IL10Ralpha mRNA. IL-10 has an suppression effect on proliferation of primary cultured hepatocytes.

Preterm birth in Caucasians is associated with coagulation and inflammation pathway gene variants

Spontaneous preterm birth (<37 weeks gestation—PTB) occurs in ∼12% of pregnancies in the United States, and is the largest contributor to neonatal morbidity and mortality. PTB is a complex disease, potentially induced by several etiologic factors from multiple pathophysiologic pathways. To dissect the genetic risk factors of PTB a large-scale high-throughput candidate gene association study was performed examining 1536 SNP in 130 candidate genes from hypothesized PTB pathways. Maternal and fetal DNA from 370 US Caucasian birth-events (172 cases and 198 controls) was examined. Single locus, haplotype, and multi-locus association analyses were performed separately on maternal and fetal data. For maternal data the strongest associations were found in genes in the complement-coagulation pathway related to decidual hemorrhage in PTB. In this pathway 3 of 6 genes examined had SNPs significantly associated with PTB. These include factor V (FV) that was previously associated with PTB, factor VII (FVII), and tissue plasminogen activator (tPA). The single strongest effect was observed in tPA marker rs879293 with a significant allelic (p = 2.30×10⁻³) and genotypic association (p = 2.0×10⁻⁶) with PTB. The odds ratio (OR) for this SNP was 2.80 [CI 1.77–4.44] for a recessive model. Given that 6 of 8 markers in tPA were statistically significant, sliding window haplotype analyses were performed and revealed an associating 4 marker haplotype in tPA (p = 6.00×10⁻³). The single strongest effect in fetal DNA was observed in the inflammatory pathway at rs17121510 in the interleukin-10 receptor antagonist (IL-10RA) gene for allele (p = 0.01) and genotype (p = 3.34×10⁻⁴). The OR for the IL-10RA genotypic additive model was 1.92 [CI 1.15–3.19] (p = 2.00×10⁻³). Finally, exploratory multi-locus analyses in the complement and coagulation pathway were performed and revealed a potentially significant interaction between a marker in FV (rs2187952) and FVII (rs3211719) (p<0.001). These results support a role for genes in both the coagulation and inflammation pathways, and potentially different maternal and fetal genetic risks for PTB.

Influence of IL-10RA and IL-22 polymorphisms on outcome of hepatitis C virus infection

BACKGROUND

Two receptor chains, IL-10RA and IL-10RB, are known to mediate the functions of interleukin-10 (IL-10), which has been shown to be involved in the progression of persistent hepatitis C virus (HCV) infection. Little information is available on the role of host genetic variation in IL-10 receptor genes and outcome of HCV infection. IL-22, an IL-10 homologue, shares the IL-10RB receptor chain with IL-10 and has antiviral properties. We investigated the possible role of polymorphisms in the IL-10RA and IL-22 genes in hepatitis C disease pathogenesis.

METHODS

This study population consisted of 631 HCV patients, recruited from several hepatology clinics across Europe. We genotyped four single-nucleotide polymorphisms (SNPs) in the IL-10RA and six SNPs in the IL-22 gene by ligation detection reaction or restriction fragment length polymorphism. Outcome of HCV infection was assessed according to viral clearance, treatment response, severity of fibrosis and overall inflammation.

CONCLUSIONS

Variation in IL-10RA appeared to be correlated with response to treatment and inflammation. Two SNPs in IL-22 affected treatment response and viral clearance respectively. We furthermore report on allele and haplotype frequencies and linkage disequilibrium for IL-10RA and IL-22. Our results indicate that genetic variation in these genes may play a modulatory role in the outcome of hepatitis C infection.

Homozygosity of the interleukin-10 receptor 1 G330R allele is associated with schizophrenia

Infections of unknown origin and an altered immune response have been hypothesized to play a role in the pathogenesis of schizophrenia. We have previously identified two single nucleotide polymorphisms (SNPs) of the IL-10 receptor 1 (IL-10R1) causing a substitution of glycine 330 to arginine (G330R) and of serine 138 to glycine (S138G). A possible association between these IL-10R1 variants and schizophrenia has been investigated in the present study. DNA of 101 unrelated Austrian patients with a DSM-III-R (Diagnostic and Statistical Manual of Mental Disorders) consensus diagnosis of schizophrenia (n = 70) or schizoaffective disorder (n = 31) and DNA of 121 German schizophrenic patients (DSM-III-R) was analyzed for the presence of S138G and G330R by allele-specific multiplex PCRs. Data from patients were compared with 250 unrelated, psychiatric healthy controls. No difference in allele frequency was detected between patients and controls (G330R: 34.0% vs. 30.0%, P = 0.208; S138G: 19.7% vs. 16.6%, P = 0.235; by Fisher's exact test). However, there was a significant difference in genotype distribution (wt/wt, wt/mut, mut/mut) for G330R between patients (46.8%, 38.3%, 14.9%) and controls (47.6%, 44.8%, 7.6%; Fisher's test P = 0.032). No such difference was seen for S138G. Our results suggest that homozygosity of the IL-10R1 G330R allele is associated with schizophrenia and may contribute to the expression of disease phenotype in susceptible individuals.

Polymorphisms of interleukin-10 and its receptor and lung function in COPD

Interleukin (IL)-10 is a type-2 T-helper cell cytokine with a broad spectrum of anti-inflammatory actions. Inflammation plays an important role in the pathogenesis of chronic obstructive pulmonary disease. It was hypothesised that single nucleotide polymorphisms (SNPs) of the genes encoding IL-10 (IL10) and the alpha subunit of its receptor (IL10RA) are associated with changes in, or value of, forced expiratory volume in one second (FEV1) in smoking-induced chronic obstructive pulmonary disease. In total, eleven SNPs of IL10 and IL10RA were studied in 586 White subjects, selected from continuous smokers followed for 5 yrs in the Lung Health Study, who showed the fastest (n=280) and slowest (n=306) decline in FEV1. These 11 SNPs were also studied in 1,072 participants exhibiting the lowest (n=538) and highest (n=534) baseline FEV1 at the beginning of the Lung Health Study. No association was found in the primary analyses. Although a subgroup analysis showed that the IL-10 3368A allele was associated with a fast decline in FEV1, the association did not pass correction for multiple comparisons. No gene-gene interaction of IL10 with IL10RA was found. There was no association of polymorphisms of the genes encoding interleukin-10 and the alpha subunit of its receptor with the rate of decline in, or value of, forced expiratory volume in one second in smoking-induced chronic obstructive pulmonary disease.

Interleukin (IL)-19, IL-20 and IL-24 are produced by and act on keratinocytes and are distinct from classical ILs

Due to their structural similarity, interleukin (IL)-19, IL-20, IL-22, IL-24 and IL-26 were combined with IL-10 in the so-called IL-10 family. To expand the knowledge on IL-19, IL-20 and IL-24, we systematically and quantitatively analysed the expression of these mediators and their receptor chains in vitro and in vivo under various conditions and in comparison with other IL-10 family members. In vitro, IL-19, IL-20 and IL-24 were produced not only by activated immune cells, particularly monocytes, but also to a similar extent by keratinocytes. IL-1beta increased the expression of these mediators 1000-fold (IL-19) and 10-fold (IL-20 and IL-24) in keratinocytes. In vivo, these cytokines were expressed preferentially in inflamed tissues. The absence of either R1 chain for the two types of receptor complexes for these cytokines (IL-20R1/IL-20R2 and IL-22R1/IL-20R2) on immune cells implies that they cannot act on these cells. In fact, IL-19, IL-20 and IL-24 did not induce activation of signal transducer and activator of transcription (STAT) molecules in immune cells. Instead, several tissues, particularly the skin, tissues from the reproductive and respiratory systems, and various glands appeared to be the main targets of these mediators. Keratinocytes expressed both receptor complexes; however, the expression of IL-22R1 was 10 times higher than that of IL-20R1. Interferon-gamma further increased the expression of IL-22R1 and decreased that of IL-20R1, suggesting that under T1 cytokine conditions these mediators primarily affect keratinocytes via the IL-22R1/IL-20R2 complex. In summary, these data support the notion that IL-19, IL-20 and IL-24 are distinct from classical ILs and constitute a separate subfamily of mediators within the IL-10 family.

Gene polymorphisms in Toll-like receptors, interleukin-10, and interleukin-10 receptor alpha and lymphoma risk

Interactions between environment and immune system play an essential role in the aetiology of immunopathologies, including lymphomas. Toll-like receptors (TLR) belong to a group of pattern recognition receptors, with importance for innate immune response and inflammatory processes. Interleukin-10 (IL-10) is a key regulatory cytokine and has been implicated in lymphomagenesis. Functional polymorphisms in these inflammation-associated genes may affect the susceptibility towards lymphoma. To test this hypothesis, we have genotyped DNA of 710 lymphoma cases and 710 controls within the context of a population-based epidemiological study for 11 functionally important single-nucleotide polymorphisms in TLR1, -2, -4, -5, -9, IL10 and IL10 receptor (IL10RA). The IL10RA Ser138Gly variant was underrepresented among lymphoma cases (odds ratio (OR)=0.81, 95 per cent confidence interval (95% CI)=0.65-1.02), mainly owing to an inverse association with Hodgkin's lymphoma (HL). The TLR2 -16933T>A variant was associated with a 2.8-fold increased risk of follicular lymphoma (95% CI=1.43-5.59) and a decreased risk of chronic lymphocytic leukaemia (OR=0.61, 95% CI=0.38-0.95). Furthermore, the TLR4 Asp299Gly variant was positively associated with the risk of mucosa-associated lymphoid tissue lymphoma (OR=2.76, 95% CI=1.12-6.81) and HL (OR=1.80, 95% CI=0.99-3.26). In conclusion, this study suggests an effect of polymorphisms in factors of the innate immune response in the aetiology of some lymphoma subtypes.