Runt-related transcription factor 3 is associated with ulcerative colitis and shows epistasis with solute carrier family 22, members 4 and 5

N-ethyl-N-nitrosourea (ENU)-induced C-terminal truncation of Runx3 results in autoimmune colitis associated with Th17/Treg imbalance

Inflammatory bowel disease (IBD) is a chronic and progressive inflammatory intestinal disease that affects people around the world. The primary cause of IBD is an imbalance in the host immune response to intestinal flora. Several human genes, including IL10, STAT3, IRGM, ATG16L1, NOD2 and RUNX3, are associated with inappropriate immune responses in IBD. It has been reported that homozygous Runx3-knockout (ko) mice spontaneously develop colitis. However, the high mortality rate in these mice within the first two weeks makes it challenging to study the role of Runx3 in colitis. To address this issue, a spontaneous colitis (SC) mouse model carrying a C-terminal truncated form of Runx3 with Tyr319stop point mutation has been generated. After weaning, SC mice developed spontaneous diarrhea and exhibited prominent enlargement of the colon, accompanied by severe inflammatory cell infiltration. Results of immunofluorescence staining showed massive CD4+ T cell infiltration in the inflammatory colon of SC mice. Colonic IL-17A mRNA expression and serum IL-17A level were increased in SC mice. CD4+ T cells from SC mice produced stronger IL-17A than those from wildtype mice in Th17-skewing conditions in vitro. In addition, the percentages of Foxp3+ Treg cells as well as the RORγt+Foxp3+ Treg subset, known for its role in suppressing Th17 response in the gut, were notably lower in colon lamina propria of SC mice than those in WT mice. Furthermore, transfer of total CD4+ T cells from SC mice, but not from wildtype mice, into Rag1-ko host mice resulted in severe autoimmune colitis. In conclusion, the C-terminal truncated Runx3 caused autoimmune colitis associated with Th17/Treg imbalance. The SC mouse model is a feasible approach to investigate the effect of immune response on spontaneous colitis.

Inflammation and Organic Cation Transporters Novel (OCTNs)

Inflammation is a physiological condition characterized by a complex interplay between different cells handled by metabolites and specific inflammatory-related molecules. In some pathological situations, inflammation persists underlying and worsening the pathological state. Over the years, two membrane transporters namely OCTN1 (SLC22A4) and OCTN2 (SLC22A5) have been shown to play specific roles in inflammation. These transporters form the OCTN subfamily within the larger SLC22 family. The link between these proteins and inflammation has been proposed based on their link to some chronic inflammatory diseases such as asthma, Crohn's disease (CD), and rheumatoid arthritis (RA). Moreover, the two transporters show the ability to mediate the transport of several compounds including carnitine, carnitine derivatives, acetylcholine, ergothioneine, and gut microbiota by-products, which have been specifically associated with inflammation for their anti- or proinflammatory action. Therefore, the absorption and distribution of these molecules rely on the presence of OCTN1 and OCTN2, whose expression is modulated by inflammatory cytokines and transcription factors typically activated by inflammation. In the present review, we wish to provide a state of the art on OCTN1 and OCTN2 transport function and regulation in relationships with inflammation and inflammatory diseases focusing on the metabolic signature collected in different body districts and gene polymorphisms related to inflammatory diseases.

Methylation of RUNX3 Promoter 2 in the Whole Blood of Children with Ulcerative Colitis

Ulcerative colitis (UC) results from a complex interplay between the environment, gut microbiota, host genetics, and immunity. Runt-related transcription factor 3 (RUNX3) regulates Th1/Th2 balance and, thus, the synthesis of cytokines and inflammation. We aimed to analyze the dependence of RUNX3 promoter 2 (P2) methylation level on: age, sex, body mass index (BMI), C-reactive protein (CRP), serum albumin, disease duration, Pediatric Ulcerative Colitis Activity Index (PUCAI), the Paris classification, and exposure to medications. This multicenter, cross-sectional study recruited hospitalized children with UC. Methylation of RUNX3 P2 was measured with methylation-sensitive restriction enzymes in the whole blood DNA. Sixty-four children were enrolled, with a mean age of 14.5 ± 2.8 years. Half of them were female (51.6%), and the average BMI Z-score was −0.44 ± 1.14. The mean methylation of RUNX3 P2 was 54.1 ± 13.3%. The methylation level of RUNX3 P2 did not correlate with age, sex, nutritional status, CRP, albumin, PUCAI, or the extent of colitis (Paris E1–E4). RUNX3 P2 methylation did not differ between patients recruited within two and a half months of diagnosis and children who had UC for at least a year. Current or past exposure to biologics, immunosuppressants, or steroids was not associated with RUNX3 P2 methylation. Methylation of RUNX3 promoter 2 in whole blood DNA does not seem to be associated with the characteristics of UC in children.

RUNX3 is up-regulated in abdominal aortic aneurysm and regulates the function of vascular smooth muscle cells by regulating TGF-β1

Abdominal aortic aneurysm (AAA) has been associated with the dysfunction of vascular smooth muscle cells (VSMCs) and extracellular matrix (ECM) remodelling. Runt-related transcription factor 3 (RUNX3) has been reported to be up-regulated in aneurysmal aorta samples compared with normal aorta. However, its function in VSMCs and the mechanism of function remains unknown. Therefore, our study aimed to investigate the role of RUNX3 in ECM remodelling and VSMC function, and further explore the underlying mechanism. Our results verified that RUNX3 was increased in aortic samples of AAA compared with healthy controls. Overexpression vectors of RUNX3 (ov-RUNX3) and siRNA of RUNX3 (si-RUNX3) were transfected into Human aortic smooth muscle cells (HAoSMCs). The results indicated that ov-RUNX3 promoted cell proliferation, migration, and MMP-2/3/9 secretion, and suppressed TIMP-1, collagen I/III, SM22, MYH11 and CNN1 expression in HAoSMCs. The silencing of RUNX3 has the opposite effect. Furthermore, we found that RUNX3 targets TGF-β1 and suppressed its transcription. The silencing of TGF-β1 increased cell proliferation, migration and MMP-2/3/9 expression, and inhibited TIMP-1, Collagen I/III, SM22, MYH11 and CNN1 expression. In addition, TGF-β1 reversed the effect of RUNX3 overexpression on HAoSMCs. Hence, our study indicated that RUNX3 promotes cell proliferation, migration, and ECM remodelling through suppressing TGF-β1.

A dual role for DNA binding by Runt in activation and repression of sloppy paired transcription

This work investigates the role of DNA binding by Runt in regulating the sloppy paired 1 (slp1) gene and in particular two distinct cis-regulatory elements that mediate regulation by Runt and other pair-rule transcription factors during Drosophila segmentation. We find that a DNA-binding-defective form of Runt is ineffective at repressing both the distal (DESE) and proximal (PESE) early stripe elements of slp1 and is also compromised for DESE-dependent activation. The function of Runt-binding sites in DESE is further investigated using site-specific transgenesis and quantitative imaging techniques. When DESE is tested as an autonomous enhancer, mutagenesis of the Runt sites results in a clear loss of Runt-dependent repression but has little to no effect on Runt-dependent activation. Notably, mutagenesis of these same sites in the context of a reporter gene construct that also contains the PESE enhancer results in a significant reduction of DESE-dependent activation as well as the loss of repression observed for the autonomous mutant DESE enhancer. These results provide strong evidence that DNA binding by Runt directly contributes to the regulatory interplay of interactions between these two enhancers in the early embryo.

Waiting in the wings: RUNX3 reveals hidden depths of immune regulation with potential implications for inflammatory bowel disease

BACKGROUND

Complex interactions between the environment and the mucosal immune system underlie inflammatory bowel disease (IBD). The involved cytokine signalling pathways are modulated by a number of transcription factors, one of which is runt-related transcription factor 3 (RUNX3).

OBJECTIVE

To systematically review the immune roles of RUNX3 in immune regulation, with a focus on the context of IBD.

METHODS

Relevant articles and reviews were identified through a Scopus search in April 2020. Information was categorized by immune cell types, analysed and synthesized. IBD transcriptome data sets and FANTOM5 regulatory networks were processed in order to complement the literature review.

RESULTS

The available evidence on the immune roles of RUNX3 allowed for its description in twelve cell types: intraepithelial lymphocyte, Th1, Th2, Th17, Treg, double-positive T, cytotoxic T, B, dendritic, innate lymphoid, natural killer and macrophages. In the gut, the activity of RUNX3 is multifaceted and context-dependent: it may promote homeostasis or exacerbated reactions via cytokine signalling and regulation of receptor expression. RUNX3 is mostly engaged in pathways involving ThPOK, T-bet, IFN-γ, TGF-β/IL-2Rβ, GATA/CBF-β, SMAD/p300 and a number of miRNAs. RUNX3 targets relevant to IBD may include RAG1, OSM and IL-17B. Moreover, in IBD RUNX3 expression correlates positively with GZMM, and negatively with IFNAR1, whereas in controls, it strongly associates with TGFBR3.

CONCLUSIONS

Dysregulation of RUNX3, mostly in the form of deficiency, likely contributes to IBD pathogenesis. More clinical research is needed to examine RUNX3 in IBD.

Transcription Factors That Regulate the Pathogenesis of Ulcerative Colitis

Ulcerative colitis (UC) is one of the inflammatory bowel diseases (IBD) characterized by occurrence in the rectum and sigmoid colon of young adults. However, the functional roles of transcription factors (TFs) and their regulating target genes and pathways are not fully known in ulcerative colitis (UC). In this study, we collected gene expression data to identify differentially expressed TFs (DETFs). We found that differentially expressed genes (DEGs) were significantly enriched in the target genes of HOXA2, IKZF1, KLF2, XBP1, EGR2, ETV7, BACH2, CBFA2T3, HLF, and NFE2. TFs including BACH2, CBFA2T3, EGR2, ETV7, NFE2, and XBP1, and their target genes were significantly enriched in signaling by interleukins. BACH2 target genes were enriched in estrogen receptor- (ESR-) mediated signaling and nongenomic estrogen signaling. Furthermore, to clarify the functional roles of immune cells on the UC pathogenesis, we estimated the immune cell proportions in all the samples. The accumulated effector CD8 and reduced proportion of naïve CD4 might be responsible for the adaptive immune response in UC. The accumulation of plasma in UC might be associated with increased gut permeability. In summary, we present a systematic study of the TFs by analyzing the DETFs, their regulating target genes and pathways, and immune cells. These findings might improve our understanding of the TFs in the pathogenesis of UC.

Difference in Pathomechanism Between Crohn's Disease and Ulcerative Colitis Revealed by Colon Transcriptome

BACKGROUND

We aim to identify the differences in colonic mucosal transcriptome between Crohn's disease (CD) and ulcerative colitis (UC) for a better understanding of the molecular pathology.

METHODS

Differentially expressed genes (DEG) in the colonic mucosa of CD and UC were identified with a global gene expression microarray dataset generated from the colon biopsies of CD and UC patients and normal controls. The DEGs were then processed to identify altered pathways and modularized DEGs and pathways. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis with an independent cohort of samples was performed to validate the microarray data.

RESULTS

At the pathway level, virus infection and autoimmune pathways were upregulated in CD but not in UC when compared with controls. Some of the relevant DEGs (such as TAP1 and TAP2) were elevated in both CD and UC, with CD exhibiting more pronounced elevations. Gene expression levels in viral infection pathways were correlated with those of autoimmune pathways. In contrast, pattern recognition-mediated innate immune pathways (TLR4 and TLR2) were significantly elevated in UC but not in CD. Similar results were observed with an independent cohort by qRT-PCR.

CONCLUSIONS

Our data support the hypothesis that viral infection induced autoimmunity may represent a pathomechanism for IBD, especially CD. However, pattern recognition-mediated innate immunity targeting microbiome may play a more important role in UC compared with CD. Our findings identified different intervention targets for CD and UC, which may lead to more effective treatments for IBD patients.

Validation of epigenetic markers to identify colitis associated cancer: Results of module 1 of the ENDCAP-C study

BACKGROUND

Chronic inflammation caused by ulcerative colitis (UC) causes a pro-neoplastic drive in the inflamed colon, leading to a markedly greater risk of invasive malignancy compared to the general population. Despite surveillance protocols, 50% of cases proceed to cancer before neoplasia is detected. The Enhanced Neoplasia Detection and Cancer Prevention in Chronic Colitis (ENDCaP-C) trial is an observational multi-centre test accuracy study to ascertain the role of molecular markers in improving the detection of dysplasia. We aimed to validate previously identified biomarkers of neoplasia in a retrospective cohort and create predictive models for later validation in a prospective cohort.

METHODS

A retrospective analysis using bisulphite pyrosequencing of an 11 marker panel (SFRP1, SFRP2, SRP4, SRP5, WIF1, TUBB6, SOX7, APC1A, APC2, MINT1, RUNX3) in samples from 35 patients with cancer, 78 with dysplasia and 343 without neoplasia undergoing surveillance for UC associated neoplasia across 6 medical centres. Predictive models for UC associated cancer/dysplasia were created in the setting of neoplastic and non-neoplastic mucosa.

FINDINGS

For neoplastic mucosa a five marker panel (SFRP2, SFRP4, WIF1, APC1A, APC2) was accurate in detecting pre-cancerous and invasive neoplasia (AUC = 0.83; 95% CI: 0.79, 0.88), and dysplasia (AUC = 0.88; (0.84, 0.91). For non-neoplastic mucosa a four marker panel (APC1A, SFRP4, SFRP5, SOX7) had modest accuracy (AUC = 0.68; 95% CI: 0.62,0.73) in predicting associated bowel neoplasia through the methylation signature of distant non-neoplastic colonic mucosa.

INTERPRETATION

This multiplex methylation marker panel is accurate in the detection of ulcerative colitis associated dysplasia and neoplasia and is currently being validated in a prospective clinical trial.

FUNDING

The ENDCAP-C study was funded by the National Institute for Health Research Efficacy and Mechanism Evaluation (EME) Programme (11/100/29).

Viewpoint: Toward the Genetic Architecture of Disease Severity in Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is characterized by uneven disease courses with various clinical outcomes. A few prognostic markers of disease severity may help stratify patients and identify those who will benefit the most from early aggressive treatment. The concept of disease severity remains too broad and vague, mainly because the definition must embrace several disease mechanisms, mainly inflammation and fibrosis, with various rates of disease progression. The magnitude of inflammation is an obvious key driver of disease severity in IBD that ultimately influence disease behavior. Advances in the genetics underlying disease severity are currently emerging, but attempts to overlap the genetics of disease susceptibility and severity have until now been unsatisfactory, suggesting that the genetic architecture of disease severity may be distinct from the genetics of disease susceptibility. In this review, we report on the current knowledge on disease severity and on the main research venues to decipher the genetic architecture of disease severity.

ERAP1/ERAP2 and RUNX3 polymorphisms are not associated with ankylosing spondylitis susceptibility in Chinese Han

Previous studies show that endoplasmic reticulum‐associated aminopeptidase (ERAP1/ERAP2) and runt‐related transcription factor 3 (RUNX3) gene polymorphisms are associated with AS (ankylosing spondylitis) in European Caucasians. However, contradictory results were reported in different Asian populations. The purpose of this study was to determine whether eleven candidate single nucleotide polymorphisms (SNPs) in ERAP1/ERAP2 and six in RUNX3 genes confer susceptibility to AS with or without acute anterior uveitis (AAU) [AS⁺AAU⁺ or AS⁺AAU^–] in Chinese Han. Therefore, a case–control association study was performed in 882 AS⁺AAU^–, 884 AS⁺AAU⁺ and 1727 healthy controls. Genotyping was performed using the iPLEXGold genotyping assay. A meta‐analysis was performed to assess the association of polymorphisms of ERAP1 with AS susceptibility in Asian populations. No association was found between SNPs of ERAP1/ERAP2/RUNX3 and susceptibility of AS with or without AAU. A case–control study between patients with human leucocyte antigen HLA‐B27‐positive and healthy controls also failed to demonstrate an association of the tested SNP with AS with or without AAU. Moreover, a meta‐analysis showed that there was no association of rs30187, rs27037, rs27980, rs27434 and rs27582 in ERAP1 with AS in Chinese Han. Taken together, 17 SNPs in ERAP1/ERAP2 and RUNX3 genes did not confer disease susceptibility to AS in Chinese Han.

Runx3 in Immunity, Inflammation and Cancer

In this chapter we summarize the pros and cons of the notion that Runx3 is a major tumor suppressor gene (TSG). Inactivation of TSGs in normal cells provides a viability/growth advantage that contributes cell-autonomously to cancer. More than a decade ago it was suggested that RUNX3 is involved in gastric cancer development, a postulate extended later to other epithelial cancers portraying RUNX3 as a major TSG. However, evidence that Runx3 is not expressed in normal gastric and other epithelia has challenged the RUNX3-TSG paradigm. In contrast, RUNX3 is overexpressed in a significant fraction of tumor cells in various human epithelial cancers and its overexpression in pancreatic cancer cells promotes their migration, anchorage-independent growth and metastatic potential. Moreover, recent high-throughput quantitative genome-wide studies on thousands of human samples of various tumors and new investigations of the role of Runx3 in mouse cancer models have unequivocally demonstrated that RUNX3 is not a bona fide cell-autonomous TSG. Importantly, accumulating data demonstrated that RUNX3 functions in control of immunity and inflammation, thereby indirectly influencing epithelial tumor development.

Genetically engineered mouse models for studying inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that is mediated by very complex mechanisms controlled by genetic, immune, and environmental factors. More than 74 kinds of genetically engineered mouse strains have been established since 1993 for studying IBD. Although mouse models cannot fully reflect human IBD, they have provided significant contributions for not only understanding the mechanism, but also developing new therapeutic means for IBD. Indeed, 20 kinds of genetically engineered mouse models carry the susceptibility genes identified in human IBD, and the functions of some other IBD susceptibility genes have also been dissected out using mouse models. Cutting-edge technologies such as cell-specific and inducible knockout systems, which were recently employed to mouse IBD models, have further enhanced the ability of investigators to provide important and unexpected rationales for developing new therapeutic strategies for IBD. In this review article, we briefly introduce 74 kinds of genetically engineered mouse models that spontaneously develop intestinal inflammation.

Runx3 specifies lineage commitment of innate lymphoid cells

Subsets of innate lymphoid cells (ILCs) reside in the mucosa and regulate immune responses to external pathogens. While ILCs can be phenotypically classified into ILC1, ILC2 and ILC3 subsets, the transcriptional control of commitment to each ILC lineage is incompletely understood. Here we report that the transcription factor Runx3 was essential for the normal development of ILC1 and ILC3 cells but not of ILC2 cells. Runx3 controlled the survival of ILC1 cells but not of ILC3 cells. Runx3 was required for expression of the transcription factor RORγt and its downstream target, the transcription factor AHR, in ILC3 cells. The absence of Runx3 in ILCs exacerbated infection with Citrobacter rodentium. Therefore, our data establish Runx3 as a key transcription factor in the lineage-specific differentiation of ILC1 and ILC3 cells.

The RUNX complex: reaching beyond haematopoiesis into immunity

Among their diverse roles as transcriptional regulators during development and cell fate specification, the RUNX transcription factors are best known for the parts they play in haematopoiesis. RUNX proteins are expressed throughout all haematopoietic lineages, being necessary for the emergence of the first haematopoietic stem cells to their terminal differentiation. Although much progress has been made since their discoveries almost two decades ago, current appreciation of RUNX in haematopoiesis is largely grounded in their lineage-specifying roles. In contrast, the importance of RUNX to immunity has been mostly obscured for historic, technical and conceptual reasons. However, this paradigm is likely to shift over time, as a primary purpose of haematopoiesis is to resource the immune system. Furthermore, recent evidence suggests a role for RUNX in the innate immunity of non-haematopoietic cells. This review takes a haematopoiesis-centric approach to collate what is known of RUNX's contribution to the overall mammalian immune system and discuss their growing prominence in areas such as autoimmunity, inflammatory diseases and mucosal immunity.

Runx3 at the interface of immunity, inflammation and cancer

Inactivation of tumor suppressor genes (TSG) in normal cells provides a viability/growth advantage that contributes cell-autonomously to cancer. More than a decade ago claims arose that the RUNX3 member of the RUNX transcription factor family is a major TSG inactivated in gastric cancer, a postulate extended later to other cancers. However, evidence that Runx3 is not expressed in normal gastric and other epithelia has challenged the RUNX3-TSG paradigm. Here we critically re-appraise this paradigm in light of recent high-throughput, quantitative genome-wide studies on thousands of human samples of various tumors and new investigations of the role of Runx3 in mouse cancer models. Collectively, these studies unequivocally demonstrate that RUNX3 is not a bona fide cell-autonomous TSG. Accordingly, RUNX3 is not recognized as a TSG and is not included among the 2000 cancer genes listed in the "Cancer Gene Census" or "Network for Cancer Genes" repositories. In contrast, RUNX3 does play important functions in immunity and inflammation and may thereby indirectly influence epithelial tumor development.

Thiopurine treatment in patients with Crohn's disease leads to a selective reduction of an effector cytotoxic gene expression signature revealed by whole-genome expression profiling

Crohn's disease (CD) is characterized by chronic inflammation of the gastrointestinal tract, as a result of aberrant activation of the innate immune system through TLR stimulation by bacterial products. The conventional immunosuppressive thiopurine derivatives (azathioprine and mercaptopurine) are used to treat CD. The effects of thiopurines on circulating immune cells and TLR responsiveness are unknown. To obtain a global view of affected gene expression of the immune system in CD patients and the treatment effect of thiopurine derivatives, we performed genome-wide transcriptome analysis on whole blood samples from 20 CD patients in remission, of which 10 patients received thiopurine treatment, compared to 16 healthy controls, before and after TLR4 stimulation with LPS. Several immune abnormalities were observed, including increased baseline interferon activity, while baseline expression of ribosomal genes was reduced. After LPS stimulation, CD patients showed reduced cytokine and chemokine expression. None of these effects were related to treatment. Strikingly, only one highly correlated set of 69 genes was affected by treatment, not influenced by LPS stimulation and consisted of genes reminiscent of effector cytotoxic NK cells. The most reduced cytotoxicity-related gene in CD was the cell surface marker CD160. Concordantly, we could demonstrate an in vivo reduction of circulating CD160(+)CD3(-)CD8(-) cells in CD patients after treatment with thiopurine derivatives in an independent cohort. In conclusion, using genome-wide profiling, we identified a disturbed immune activation status in peripheral blood cells from CD patients and a clear treatment effect of thiopurine derivatives selectively affecting effector cytotoxic CD160-positive cells.

Single-nucleotide polymorphisms in inflammatory bowel disease

Strong evidence indicates that inflammatory bowel disease, including Crohn disease and ulcerative colitis, is a result of an inappropriate inflammatory response in which genetic and environmental factors play important roles. This review discusses several single-nucleotide polymorphisms with either susceptibility or protective effects on inflammatory bowel disease.

Colonic expression of Runx3 protein and TGF-β(1) and their correlation in patients with irritable bowel syndrome

OBJECTIVE

To investigate the role of Runx3 protein and TGF-β(1) in the pathogenesis of irritable bowel syndrome (IBS), as well as the correlation of these two proteins.

METHODS

Colonic tissue was collected from patients with IBS and normal persons. The colonic expression of Runx3 protein and TGF-β(1) was detected with immunohistochemistry method. Semi-quantitative analysis was used to evaluate the staining degree of these two proteins.

RESULTS

Compared with their counterparts, patients with IBS did not show any changes in the colonic expression of Runx3 protein and TGF-β(1) (P>0.05). Interestingly, there was a significant correlation between Runx3 protein and TGF-β(1) in patients with IBS(P<0.05).

CONCLUSIONS

The role of Runx3 protein and TGF-β(1) in the pathogenesis of IBS remains to be further studied.

Association between OCTN1/2 gene polymorphisms (1672C-T, 207G-C) and susceptibility of Crohn's disease: a meta-analysis

PURPOSE

Although a number of genetic studies have attempted to link organic cation transporter 1/2 (OCTN1/2) polymorphisms to susceptibility of Crohn's disease (CD), the results were often inconsistent. The present study aimed at investigating the associations.

METHODS

The PubMed, EBSCO, and BIOSIS databases were searched to identify eligible studies which were published in English before April 2011. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI).

RESULTS

A total of 15 case-control studies, containing 4,489 cases/5,351 controls for OCTN1 and 4,474 cases/5,377 controls for OCTN2 were included. Overall, significant associations were found between OCTN1/2 polymorphisms and susceptibility of Crohn's disease for all genetic models. In the subgroup analyses, significant associations were found in the Caucasian population for OCTN1 (TT vs. CC: OR = 1.425, 95% CI 1.247-1.628; TT vs. CT: OR = 1.299, 95% CI 1.149-1.468; dominant model: OR = 1.344, 95% CI 1.197-1.508; and recessive model: OR = 1.179, 95% CI 1.066-1.305) and for OCTN2 (CC vs. GG: OR = 1.309, 95% CI 1.078-1.588; CC vs. CG: OR = 1.200, 95% CI 1.002-1.438; dominant model (OR = 1.231, 95% CI 1.036-1.462; recessive model: OR = 1.148, 95% CI 1.031-1.279). Significant associations were not found in the East Asian population.

CONCLUSIONS

This meta-analysis suggests that OCTN1/2 polymorphisms were associated with susceptibility of CD in the Caucasian population but not in the East Asian population.

Haplotype in the IBD5 region is associated with refractory Crohn's disease in Slovenian patients and modulates expression of the SLC22A5 gene

BACKGROUND

The IBD5 locus (OMIM ID 606348) on chromosome 5 was suggested to be one of the most important genetic factors involved in the pathogenesis of inflammatory bowel diseases (IBDs). However the main contributor from this region is still unknown.

METHODS

We investigated the possible association of the IBD5 locus with IBD in Slovenian patients and correlation between disease-associated single nucleotide polymorphisms (SNPs) and quantitative gene expression (eQTL) of candidate genes from the IBD5 locus in peripheral blood lymphocytes and colon tissue biopsies from IBD patients. We genotyped SNPs from the IBD5 locus in 312 healthy controls and 632 IBD patients.

RESULTS

We found statistically significant association of polymorphisms rs1050152 in gene SLC22A4 (p = 0.005, OR = 2.177, 95% CI = 1.270-3.526) and rs2631372 in gene SLC22A5 (p = 0.001, OR = 0.473, 95% CI = 0.307-0.731) and TC haplotype of both polymorphisms (p = 0.006, OR = 1,541, 95% CI = 1.130-2.100) with refractory Crohn's disease (CD) in Slovenian patients who do not respond to standard therapy, including patients who develop fistulas. We found decreased expression of SLC22A4 and SLC22A5 genes in peripheral blood lymphocytes from IBD patients compared to control group and decreased expression of SLC22A5 gene in inflamed tissue biopsies compared to noninflamed colon (p = 0.009). We found lower expression of SLC22A5 gene in IBD patients with disease-susceptible genotypes for both disease-associated SNPs.

CONCLUSIONS

Our data suggest that SNPs and haplotype in the IBD5 SLC22A4/SLC22A5 region contribute to the development of particularly refractory Crohn's disease in the Slovenian population, and expression studies in blood lymphocytes and colon tissue biopsies and eQTL analysis suggest that SLC22A5 is the main gene in the IBD5 region contributing to the IBD pathogenesis.

Chromatin immunoprecipitation and association study revealed a possible role of Runt-related transcription factor 3 in the ulcerative colitis of Chinese population

RUNX3 was recently found to be associated with ulcerative colitis. In this study, downstream target genes of RUNX3 were identified by chromatin immunoprecipitation and promoter sequence microarray chips. Polymorphisms of RUNX3 and its 2 putative downstream (OCTN1 and PPAR-gamma) target genes were genotyped by PCR-SSP and sequencing in 144 Chinese UC patients and 151 healthy controls. Expression of RUNX3 in colonic mucosa of UC patients was detected by immunohistochemical staining. Twelve genes involved in IBD were identified as the downstream target genes of RUNX3. The RUNX3 rs2236851 CT genotype was associated significantly with UC susceptibility and risk of early onset in Chinese population. No association of OCTN1 and PPAR-gamma with UC susceptibility or subphenotypes was identified. RUNX3 expression was significantly increased in UC mucosa. Therefore, RUNX3 might be involved in UC pathogenesis by regulating the expression of genes related with immune response.

Genetic variants in the Runt-related transcription factor 3 gene contribute to gastric cancer risk in a Chinese population

Runt-related transcription factor 3 (RUNX3) is a well known gene for its functions in gastric cancer suppression, but the effect of its genetic variations on the risk of gastric cancer remains unclear. In this study, ten tagging single nucleotide polymorphisms (tSNPs) of the RUNX3 gene were selected and genotyped in a hospital-based case-control study of 312 gastric cancer patients and 329 cancer-free controls in a Chinese population. In the single-locus analysis, three RUNX3 intronic tSNPs associated with significantly increased risk of gastric cancer were observed: the SNP3 rs11249206 CC genotype (adjusted odds ratio [OR] = 1.75, 95% confidence interval [CI] = 1.03-2.99), compared with the TT genotype; the SNP7 rs760805 AA genotype (adjusted OR = 1.82, 95% CI = 1.14-2.92), compared with the TT genotype; and the SNP8 rs2236852 GG genotype (adjusted OR = 1.69, 95% CI = 1.05-2.72), compared with the AA genotype. In the combined analyses of these three tSNPs, we found that the combined genotypes with four to six variant (risk) alleles (i.e. SNP3 C, SNP7 A, and SNP8 G alleles) were associated with an increased risk of gastric cancer compared with those with one to three variant (risk) alleles (adjusted OR = 2.00, 95% CI = 1.41-2.85), and this increased risk was more pronounced among subgroups of age > or =65 years, never smokers, and never drinkers. However, no significant association was observed in the clinicopathological features analyses. In conclusion, the RUNX3 genetic variants may modulate the risk of gastric cancer in a Chinese population. Further larger and functional studies are warranted to validate the findings.