Polymorphisms of the TNF Gene and Three Susceptibility Loci Are Associated with Crohn's Disease and Perianal Fistula Crohn's Disease: A Study among the Han Population from South China

Interaction of Th17 differentiations-related gene polymorphisms and environmental factors contributing to the disease classification, complications, and surgical risks of Crohn's disease in the Chinese Han population

OBJECTIVES

Few studies have been conducted on gene-environment interactions in the Chinese population with Crohn's disease (CD). We aimed to investigate the association between single nucleotide polymorphisms (SNPs) on the T helper 17 (Th17) cell and CD susceptibility/performance in Chinese individuals.

METHODS

We conducted a case-control and case-only study at the Peking Union Medical College Hospital. Four SNPs related to the Th17 cell pathway genes were prioritized, including rs2284553 (interferon gamma receptor 2), rs7517847 (interleukin 23 receptor), rs7773324 (interferon regulatory factor 4), and rs4263839 (tumor necrosis factor superfamily 15). SNP frequency was calculated, and gene-environment interaction was assessed by multifactor dimensionality reduction analysis.

RESULTS

Altogether 159 CD patients and 316 healthy controls were included. All analyzed SNPs were found in Hardy-Weinberg equilibrium (P > 0.05). The frequency of rs2284553-A allele and rs4263839-A allele were lower in CD patients compared with controls (P < 0.05). While the rs4263839-A allele was more prevalent in ileocolonic CD patients than in those with isolated small intestinal or colonic disease (P = 0.035). Gene-environment interactions revealed associations between rs2284553 and breastfeeding, sunshine exposure, and fridge-stored food, affecting age at diagnosis, intestinal involvement, and intestinal stricture. Interaction of rs4263839 and breastfeeding influenced small intestinal lesions and intestinal stricture in CD.

CONCLUSIONS

This study provided information on the genetic background in Chinese CD patients. Incorporating these SNPs into predictive models may improve risk assessment and outcome prediction. Gene-environment interaction contributes to the understanding of CD pathogenesis.

Transcriptome-wide association studies associated with Crohn's disease: challenges and perspectives

Crohn's disease (CD) is regarded as a lifelong progressive disease affecting all segments of the intestinal tract and multiple organs. Based on genome-wide association studies (GWAS) and gene expression data, transcriptome-wide association studies (TWAS) can help identify susceptibility genes associated with pathogenesis and disease behavior. In this review, we overview seven reported TWASs of CD, summarize their study designs, and discuss the key methods and steps used in TWAS, which affect the prioritization of susceptibility genes. This article summarized the screening of tissue-specific susceptibility genes for CD, and discussed the reported potential pathological mechanisms of overlapping susceptibility genes related to CD in a certain tissue type. We observed that ileal lipid-related metabolism and colonic extracellular vesicles may be involved in the pathogenesis of CD by performing GO pathway enrichment analysis for susceptibility genes. We further pointed the low reproducibility of TWAS associated with CD and discussed the reasons for these issues, strategies for solving them. In the future, more TWAS are needed to be designed into large-scale, unified cohorts, unified analysis pipelines, and fully classified databases of expression trait loci.

The Relation of VEGFA, VEGFR2, VEGI, and HIF1A Genetic Variants and Their Serum Protein Levels with Breast Cancer in Egyptian Patients

Breast cancer is the most common type of cancer in Egyptian females. Polymorphisms in the angiogenesis pathway have been implicated previously in cancer risk and prognosis. The aim of the current study was to determine whether certain polymorphisms in the genes of vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2), vascular endothelial growth inhibitor (VEGI), and hypoxia-inducible factor-1α (HIF1A) associated with breast cancer development. The study included 154 breast cancer patients and 132 apparently healthy age-matched females as a control group. VEGFA rs25648 genotyping was performed using (ARMS) PCR technique; while VEGFR2 rs2071559, VEGI rs6478106, and HIF-1α rs11549465 were genotyped by the PCR-RFLP method. Serum levels of VEGF, VEGFR2, VEGI, and HIF1A proteins in breast cancer patients and controls were measured by ELISA. There was a significant association between the VEGFA rs25648 C allele and breast cancer risk (OR 2.5, 95% CI 1.7-3.6, p < 0.001). VEGFA rs25648 C/C genotype was statistically significantly higher in breast cancer patients vs. control (p < 0.001). Participants with the T/T and T/C VEGFR2 rs2071559 genotypes had 5.46 and 5 higher odds, respectively, of having breast cancer than those with the C/C genotype. For the VEGI rs6478106 polymorphism, there was a higher proportion of C allele in breast cancer patients vs. control (p = 0.003). Moreover, the C/C genotype of VEGI rs6478106 was statistically significantly higher in breast cancer patients vs. control (p = 0.001). There was no significant difference in genotypes and allele frequencies of HIF1A rs11549465 polymorphism between breast cancer cases and control individuals (p > 0.05). Serum levels of VEGFA, VEGI, and HIF1A were considerably greater in women with breast cancer than in the control (p < 0.001). In conclusion, the genetic variants VEGFA rs25648, VEGFR2 rs2071559, and VEGI rs6478106 revealed a significant association with increased breast cancer risk in Egyptian patients.

ATG16L1 rs2241880/T300A increases susceptibility to perianal Crohn's disease: An updated meta-analysis on inflammatory bowel disease risk and clinical outcomes

BACKGROUND

ATG16L1 plays a fundamental role in the degradative intracellular pathway known as autophagy, being a mediator of inflammation and microbial homeostasis. The variant rs2241880 can diminish these capabilities, potentially contributing to inflammatory bowel disease (IBD) pathogenesis.

OBJECTIVES

To perform an updated meta-analysis on the association between ATG16L1 rs2241880 and IBD susceptibility by exploring the impact of age, ethnicity, and geography. Moreover, to investigate the association between rs2241880 and clinical features.

METHODS

Literature searches up until September 2022 across 7 electronic public databases were performed for all case-control studies on ATG16L1 rs2241880 and IBD. Pooled odds ratios (ORP ) and 95% CI were calculated under the random effects model.

RESULTS

Our analyses included a total of 30,606 IBD patients, comprising 21,270 Crohn's disease (CD) and 9336 ulcerative colitis (UC) patients, and 33,329 controls. ATG16L1 rs2241880 was significantly associated with CD susceptibility, where the A allele was protective (ORP : 0.74, 95% CI: 0.72-0.77, p-value: <0.001), while the G allele was a risk factor (ORP : 1.23, 95% CI: 1.09-1.39, p-value: 0.001), depending on the minor allele frequencies observed in this multi-ancestry study sample. rs2241880 was predominantly relevant in Caucasians from North America and Europe, and in Latin American populations. Importantly, CD patients harbouring the G allele were significantly more predisposed to perianal disease (ORP : 1.21, 95% CI: 1.07-1.38, p-value: 0.003).

CONCLUSIONS

ATG16L1 rs2241880 (G allele) is a consistent risk factor for IBD in Caucasian cohorts and influences clinical outcomes. As its role in non-Caucasian populations remains ambiguous, further studies in under-reported populations are necessary.

Where Are We and Where to Next?-The Future of Perianal Crohn's Disease Management

Perianal fistulizing Crohn's Disease (pCD) affects about 25% of patients with Crohn's Disease (CD). It remains a difficult entity to manage with a therapeutic ceiling of treatment success despite improving medical and surgical management. The refractory nature of the disease calls for an imminent need to better understand its immunopathogenesis and classification to better streamline our treatment options. In this article, we overview the current state of pCD management and discuss where the future of its management may lie.

A Review on Inflammatory Bowel Diseases: Recent Molecular Pathophysiology Advances

Inflammatory bowel diseases are considered immune disorders with a complex genetic architecture involving constantly changing endogenous and exogenous factors. The rapid evolution of genomic technologies and the emergence of newly discovered molecular actors are compelling the research community to reevaluate the knowledge and molecular processes. The human intestinal tract contains intestinal human microbiota consisting of commensal, pathogenic, and symbiotic strains leading to immune responses that can contribute and lead to both systemic and intestinal disorders including IBD. In this review, we attempted to highlight some updates of the new IBD features related to genomics, microbiota, new emerging therapies and some major established IBD risk factors.

Cell Type-Specific Induction of Inflammation-Associated Genes in Crohn’s Disease and Colorectal Cancer

Based on the rapid increase in incidence of inflammatory bowel disease (IBD), the identification of susceptibility genes and cell populations contributing to this condition is essential. Previous studies suggested multiple genes associated with the susceptibility of IBD; however, due to the analysis of whole-tissue samples, the contribution of individual cell populations remains widely unresolved. Single-cell RNA sequencing (scRNA-seq) provides the opportunity to identify underlying cellular populations. We determined the enrichment of Crohn’s disease (CD)-induced genes in a publicly available Crohn’s disease scRNA-seq dataset and detected the strongest induction of these genes in innate lymphoid cells (ILC1), highly activated T cells and dendritic cells, pericytes and activated fibroblasts, as well as epithelial cells. Notably, these genes were highly enriched in IBD-associated neoplasia, as well as sporadic colorectal cancer (CRC). Indeed, the same six cell populations displayed an upregulation of CD-induced genes in a CRC scRNA-seq dataset. Finally, after integrating and harmonizing the CD and CRC scRNA-seq data, we demonstrated that these six cell types display a gradual increase in gene expression levels from a healthy state to an inflammatory and tumorous state. Together, we identified cell populations that specifically upregulate CD-induced genes in CD and CRC patients and could, therefore, contribute to inflammation-associated tumor development.