Telomere length in non-neoplastic colonic mucosa in ulcerative colitis (UC) and its relationship to the severe clinical phenotypes

ERCC4: a potential regulatory factor in inflammatory bowel disease and inflammation-associated colorectal cancer

The pathogenesis of inflammatory bowel disease (IBD) remains unclear and is associated with an increased risk of developing colitis-associated cancer (CAC). Under sustained inflammatory stimulation in the intestines, loss of early DNA damage response genes can lead to tumor formation. Many proteins are involved in the pathways of DNA damage response and play critical roles in protecting genes from various potential damages that DNA may undergo. ERCC4 is a structure-specific endonuclease that participates in the nucleotide excision repair (NER) pathway. The catalytic site of ERCC4 determines the activity of NER and is an indispensable gene in the NER pathway. ERCC4 may be involved in the imbalanced process of DNA damage and repair in IBD-related inflammation and CAC. This article primarily reviews the function of ERCC4 in the DNA repair pathway and discusses its potential role in the processes of IBD-related inflammation and carcinogenesis. Finally, we explore how this knowledge may open novel avenues for the treatment of IBD and IBD-related cancer.

A new face of old cells: An overview about the role of senescence and telomeres in inflammatory bowel diseases

Cellular senescence is a pivotal factor contributing to aging and the pathophysiology of age-related diseases. Despite the presence of inflammation and abnormal immune system function in both inflammatory bowel diseases (IBD) and senescence, the relationship between the two remains largely unexplored. Therefore, our study aimed to investigate the intricate connection between cellular senescence, telomeres, and IBD. The review highlights the presence of senescence markers, particularly p16 and p21, in IBD patients, suggesting their potential association with disease progression and mucosal inflammation. We emphasize the critical role of macrophages in eliminating senescent cells and how disturbance in effective clearance may contribute to persistent senescence and inflammation in IBD. Additionally, we shed light on the involvement of telomeres in IBD, as their dysfunction impairs enterocyte function and disrupts colonic barrier integrity, potentially exacerbating the pathogenesis of the disease. Targeting senescence and telomere dysfunctions holds promise for the development of innovative therapeutic approaches to mitigate intestinal inflammation and alleviate symptoms in IBD patients. By unraveling the precise role of senescence in IBD, we can pave the way for the discovery of novel therapeutic interventions that effectively address the underlying mechanisms of intestinal inflammation, offering hope for improved management and treatment of IBD patients.

Importance of Telomere Shortening in the Pathogenesis of Ulcerative Colitis: A New Treatment From the Aspect of Telomeres in Intestinal Epithelial Cells

BACKGROUND AND AIMS

Ulcerative colitis [UC] is a chronic inflammatory disease of the colon with frequent relapses. Telomere shortening in intestinal epithelial cells has been reported in severe or longstanding cases. However, its influence on UC pathogenesis remains unelucidated. To this end, we evaluated telomere shortening using a long-term organoid inflammation model that we had originally established.

METHODS

A UC model using human colon organoids was established to assess telomere changes chronologically. MST-312 was used for the telomerase inhibition assay. The potential of telomerase activators as a novel UC treatment was evaluated with an in vitro model, including microarray analysis, and histological changes were assessed using xenotransplantation into mouse colonic mucosa.

RESULTS

Our UC model reproduced telomere shortening in vitro, which was induced by the continuous suppression of telomerase activity via P53. MST-312-based analysis revealed that telomere shortening was involved in the pathogenesis of UC. Madecassoside [MD] improved the telomere length of the UC model and UC patient-derived organoids, which further promoted cell proliferation in vitro and improved the graft take-rate of xenotransplantation. Moreover, histological analysis revealed that MD induced normal crypt structure with abundant goblet cells.

CONCLUSIONS

This study is the first to reveal the mechanism and importance of telomere shortening in the pathogenesis of UC. MD could be a novel candidate for UC treatment beyond endoscopic mucosal healing.

Telomeres: New players in immune-mediated inflammatory diseases?

Telomeres are repetitive DNA sequences located at the ends of linear chromosomes that preserve the integrity and stability of the genome. Telomere dysfunctions due to short telomeres or altered telomere structures can ultimately lead to replicative cellular senescence and chromosomal instability, both mechanisms being hallmarks of ageing. Chronic inflammation, oxidative stress and finally telomere length (TL) dynamics have been shown to be involved in various age-related non-communicable diseases (NCDs). Immune-mediated inflammatory diseases (IMIDs), including affections such as inflammatory bowel disease, psoriasis, rheumatoid arthritis, spondyloarthritis and uveitis belong to this group of age-related NCDs. Although in recent years, we have witnessed the emergence of studies in the literature linking these IMIDs to TL dynamics, the causality between these diseases and telomere attrition is still unclear and controversial. In this review, we provide an overview of available studies on telomere dynamics and discuss the utility of TL measurements in immune-mediated inflammatory diseases.

Telomere dysfunction activates YAP1 to drive tissue inflammation

Germline telomere maintenance defects are associated with an increased incidence of inflammatory diseases in humans, yet whether and how telomere dysfunction causes inflammation are not known. Here, we show that telomere dysfunction drives pATM/c-ABL-mediated activation of the YAP1 transcription factor, up-regulating the major pro-inflammatory factor, pro-IL-18. The colonic microbiome stimulates cytosolic receptors activating caspase-1 which cleaves pro-IL-18 into mature IL-18, leading to recruitment of interferon (IFN)-γ-secreting T cells and intestinal inflammation. Correspondingly, patients with germline telomere maintenance defects exhibit DNA damage (γH2AX) signaling together with elevated YAP1 and IL-18 expression. In mice with telomere dysfunction, telomerase reactivation in the intestinal epithelium or pharmacological inhibition of ATM, YAP1, or caspase-1 as well as antibiotic treatment, dramatically reduces IL-18 and intestinal inflammation. Thus, telomere dysfunction-induced activation of the ATM-YAP1-pro-IL-18 pathway in epithelium is a key instigator of tissue inflammation.

Role of telomere shortening in anticipation of inflammatory bowel disease

BACKGROUND

The existence of genetic anticipation has been long disputed in inflammatory bowel disease (IBD) in the absence of the explanatory mechanism.

AIM

To determine whether it was predictive of genetic anticipation, we evaluated telomere length in IBD. We hypothesized that multiplex IBD families exhibit a genetic defect impacting telomere maintenance mechanisms.

METHODS

We studied three IBD families with multiple affected members in three successive generations. We determined telomere length (TL) in lymphocytes and granulocytes from peripheral blood of the affected members using flow cytometry and fluorescence in-situ hybridization (flow FISH). We also performed whole exome sequencing in the blood of all available family members and used PhenoDB to identify potential candidate gene variants with recessive or dominant modes of inheritance.

RESULTS

Out of twenty-four patients of European descent selected to participate in the study, eleven patients, eight parent-child pairs affected by IBD, were included in the genetic anticipation analysis. Median difference in age at diagnosis between two successive generations was 16.5 years, with earlier age at onset in the younger generations. In most of the affected members, the disease harbored similar gastrointestinal and extraintestinal involvement but was more aggressive among the younger generations. TL was not associated with earlier age at onset or more severe disease in members of successive generations affected by IBD. NOD2 gene mutations were present in the Crohn’s disease patients of one family. However, no gene variants were identified as potential candidates for inheritance.

CONCLUSION

Telomere shortening appears unlikely to be involved in mechanisms of possible genetic anticipation in IBD. Further studies using a larger sample size are required to confirm or refute our findings.

Telomere Maintenance-Associated PML Is a Potential Specific Therapeutic Target of Human Colorectal Cancer

Telomere length maintenance is essential for cell proliferation, which is particularly prominent in cancer. We validate that the primary colorectal tumors exhibit heterogeneous telomere lengths but mostly (90%) short telomeres relative to normal tissues. Intriguingly, relatively short telomeres are associated with tumor malignancy as indicated by poorly differentiated state, and these tumors contain more cancer stem-like cells (CSLCs) identified by several commonly used markers CD44, EPHB2 or LGR5. Moreover, promyelocytic leukemia (PML) and ALT-associated PML nuclear bodies (APBs) are frequently found in tumors with short telomeres and high proliferation. In contrast, distant normal tissues rarely or only minimally express PML. Inhibition of PML and APBs by an ATR inhibitor decreases proliferation of CSLCs and organoids, suggesting a potential therapeutic target to progressive colorectal tumors. Together, telomere maintenance underling tumor progression is connected with CSLCs.

Telomere length in the colon is related to colorectal adenoma prevalence

Telomere length has been associated with risk of several cancers. However, studies of the relationship between telomere length and colorectal cancer risk have been inconsistent. This study examined the relationship between telomere length in normal colon tissue and the prevalence of colorectal adenoma, a precursor to colorectal cancer. This nested case-control study consisted of 85 patients aged 40 to 65 undergoing a screening colonoscopy: 40 cases with adenoma(s) detected at colonoscopy and 45 controls with normal colonoscopy. During the colonoscopy, two pinch biopsies of healthy, normal appearing mucosa were obtained from the descending colon. Relative telomere length (rTL) was quantified in DNA extracted from colon mucosa using quantitative real-time PCR. Logistic regression was used to assess the relationship between telomere length and adenoma prevalence and estimate odds ratios and 95% confidence intervals. rTL was significantly longer in colon tissue of individuals with adenomas compared to healthy individuals (p = 0.008). When rTL was categorized into quartiles according to the distribution of rTL among controls, individuals with the longest telomeres had increased odds of adenoma when compared to individuals with shortest telomeres (OR = 4.58, 95% CI: 1.19, 17.7). This study suggests that long telomeres in normal colon tissue are associated with increased colorectal cancer risk.

CD177+ neutrophils as functionally activated neutrophils negatively regulate IBD

BACKGROUND

Neutrophils are accumulated in inflamed mucosa of IBD and play an important role in the pathogenesis. CD177 is expressed in neutrophils specifically and upregulated during inflammation. However, the role of CD177⁺ neutrophils in pathogenesis of IBD remains elusive.

MATERIALS AND METHODS

Expression of CD177 was analysed in peripheral blood and intestinal mucosa from patients with IBD using quantitative RT-PCR, flow cytometry and immunohistochemistry. CD177⁺ and CD177^- neutrophils were isolated to determine gene differences by RNA sequencing. Colitis was established in CD177^-/- and wild-type mice in response to dextran sulfate sodium (DSS) insults to determine the role of CD177⁺ neutrophils in IBD.

RESULTS

CD177⁺ neutrophils were markedly increased in peripheral blood and inflamed mucosa from patients with active IBD compared with healthy controls. RNA sequencing revealed that differential gene expression between CD177⁺ and CD177^- neutrophils from patients with IBD was associated with response to bacterial defence, hydrogen peroxide and reactive oxygen species (ROS). CD177⁺ neutrophils produced lower levels of proinflammatory cytokines (ie, interferon-γ, interleukin (IL)-6, IL-17A), but higher levels of IL-22 and transforming growth factor-β, and exhibited increased bactericidal activities (ie, ROS, antimicrobial peptides, neutrophil extracellular trap) compared with CD177^- subset. CD177^-/- mice developed more severe colitis on DSS insults compared with wild-type mice. Moreover, CD177 deficiency led to compromised intestinal barrier and impaired antibacterial immunity through decreased production of IL-22 by CD177^- neutrophils.

CONCLUSIONS

CD177⁺ neutrophils represent functionally activated population and play a protective role in IBD through increased bactericidal activity and IL-22 production. Targeting CD177⁺ neutrophils may be beneficial for treatment of IBD.

Precancer in ulcerative colitis: the role of the field effect and its clinical implications

Cumulative evidence indicates that a significant proportion of cancer evolution may occur before the development of histological abnormalities. While recent improvements in DNA sequencing technology have begun to reveal the presence of these early preneoplastic clones, the concept of 'premalignant field' was already introduced by Slaughter more than half a century ago. Also referred to as 'field effect', 'field defect' or 'field cancerization', these terms describe the phenomenon by which molecular alterations develop in normal-appearing tissue and expand to form premalignant patches with the potential to progress to dysplasia and cancer. Field effects have been well-characterized in ulcerative colitis, an inflammatory bowel disease that increases the risk of colorectal cancer. The study of the molecular alterations that define these fields is informative of mechanisms of tumor initiation and progression and has provided potential targets for early cancer detection. Herein, we summarize the current knowledge about the molecular alterations that comprise the field effect in ulcerative colitis and the clinical utility of these fields for cancer screening and prevention.

Potential link between Fusobacterium enrichment and DNA methylation accumulation in the inflammatory colonic mucosa in ulcerative colitis

BACKGROUND AND AIM

Fusobacterium enrichment has been associated with colorectal cancer development. Ulcerative colitis (UC) associated tumorigenesis is characterized as high degree of methylation accumulation through continuous colonic inflammation. The aim of this study was to investigate a potential link between Fusobacterium enrichment and DNA methylation accumulation in the inflammatory colonic mucosa in UC.

METHODS

In the candidate analysis, inflamed colonic mucosa from 86 UC patients were characterized the methylation status of colorectal a panel of cancer related 24 genes. In the genome-wide analysis, an Infinium HumanMethylation450 BeadChip array was utilized to characterize the methylation status of >450,000 CpG sites for fourteen UC patients. Results were correlated with Fusobacterium status.

RESULTS

UC with Fusobacterium enrichment (FB-high) was characterized as high degree of type C (for cancer-specific) methylation compared to other (FB-low/neg) samples (P<0.01). Genes hypermethylated in FB-high samples included well-known type C genes in colorectal cancer, such as MINT2 and 31, P16 and NEUROG1. Multivariate analysis demonstrated that the FB high status held an increased likelihood for methylation high as an independent factor (odds ratio: 16.18, 95% confidence interval: 1.94-135.2, P=0.01). Genome-wide methylation analysis demonstrated a unique methylome signature of FB-high cases irrespective of promoter, outside promoter, CpG and non-CpG sites. Group of promoter CpG sites that were exclusively hypermethylated in FB-high cases significantly codified the genes related to the catalytic activity (P=0.039).

CONCLUSION

Our findings suggest that Fusobacterium accelerates DNA methylation in specific groups of genes in the inflammatory colonic mucosa in UC.

CD99 refers to the activity of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD), composed of Crohn's disease (CD) and ulcerative colitis (UC), is an inflammatory autoimmune disease. CD99 has been reported to participate in migration of leukocytes and T cell activation. However, the roles of CD99 in IBD are obscure.

MATERIALS AND METHODS

CD99 expression was examined in peripheral blood mononuclear cells (PBMCs) and inflamed mucosa from IBD patients by qRT-PCR. Serum TNF-α and IL-17A levels were detected by ELISA. Correlations of CD99 expression with TNF-α, IL-17A, Crohn's disease activity index (CDAI), simple endoscopic score for CD (SES-CD), Mayo index, and Truelove grading were performed by Pearson's correlation.

RESULTS

CD99 expression was increased in PBMCs and inflamed mucosa from active CD and UC patients, and CD99 expression was also increased in the inflamed mucosa compared with unaffected control from the same patients. Serum TNF-α and IL-17A levels were increased in active CD or UC patients, and positively correlated with CD99 expression in PBMCs (CD: r = .402, p = .009; r = .350, p = .025. UC: r = .289, p = .028; r = .322, p = .014). Moreover, CD99 expression in inflamed mucosa was correlated with CDAI, SES-CD, Mayo index, and Truelove grading (r = .410, p = .012; r = .341, p = .005; r = .366, p = .002; r = .312, p = .011).

CONCLUSION

CD99 expression is increased in patients with active IBD, and positively correlated with disease activity. Therefore, CD99 expression can be used as an index to evaluate the activity of IBD.

Comprehensive DNA Methylation Profiling of Inflammatory Mucosa in Ulcerative Colitis

INTRODUCTION

Aberrant DNA methylation frequently occurs in the inflammatory mucosa in ulcerative colitis (UC) and is involved in UC-related tumorigenesis. We performed comprehensive DNA methylation profiling of the promoter regions of the inflamed rectal mucosae of patients with UC.

DESIGN

The methylation status of the promoter CpG islands (CGIs) of 45 cancer/inflammation or age-related candidate genes and the LINE1 repetitive element were examined in the colonic mucosae of 84 cancer-free patients with UC by bisulfite pyrosequencing. Methylation status of selected genes (DPYS, N33, MIR1247, GSTP1, and SOX11) was also determined in 14 neoplastic lesions (5 with high-grade dysplasia and 9 with carcinoma) and 8 adjacent tissues derived from 12 patients. An Infinium HumanMethylation450 BeadChip array was used to characterize the methylation status of >450,000 CpG sites for 10 patients with UC.

RESULTS

Clustering analysis based on the methylation status of the candidate genes clearly distinguished the inflammatory samples from the noninflammatory samples. The hypermethylation of the promoter CGIs strongly correlated with increased disease duration, which is a known risk factor for the development of colon cancer. Genome-wide methylation analyses revealed a high rate of hypermethylation in the severe phenotype of UC, particularly at the CGIs. Exclusively hypermethylated promoter CGIs in the severe phenotypes were significantly related to genes involved in biosynthetic processes, the regulation of metabolic processes, and nitrogen compound metabolic processes.

CONCLUSION

Our findings suggest the potential utility of DNA methylation as a molecular marker and therapeutic target for UC-related tumorigenesis.

Blockade of PLD2 Ameliorates Intestinal Mucosal Inflammation of Inflammatory Bowel Disease

Background. Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronically remittent and progressive inflammatory disorders. Phospholipase D2 (PLD2) is reported to be involved in the pathogenesis of several inflammatory diseases. However, the exact role of PLD2 in IBD is obscure. Methods. PLD2 expression was determined in peripheral blood cells and inflamed mucosa from patients with IBD by qRT-PCR. Colonic biopsies were also obtained from CD patients before and after infliximab (IFX) treatment to examine PLD2 expression. PLD2 selective inhibitor (CAY10594) was administrated daily by oral gavage in DSS-induced colitis mice. Bone marrow neutrophils from colitis mice were harvested to examine the migration using Transwell plate. Results. PLD2 was found to be significantly increased in peripheral blood cells and inflamed mucosa in patients with active IBD. Treatment with IFX could significantly decrease PLD2 expression in intestinal mucosa in patients with CD. Moreover, blockade of PLD2 with CAY10594 could markedly ameliorate DSS-induced colitis in mice and promote neutrophil migration. Conclusions. PLD2 plays a critical role in the pathogenesis of IBD. Blockade of PLD2 may serve as a new therapeutic approach for treatment of IBD.

Identifying molecular features associated with psychoneurological symptoms in women with breast cancer using multivariate mixed models

Breast cancer (BC) is the second most common cancer among women. Research shows many women with BC experience anxiety, depression, and stress (ADS). Epigenetics has recently emerged as a potential mechanism for the development of depression.1 Although there are growing numbers of research studies indicating that epigenetic changes are associated with ADS, there is currently no evidence that this association is present in women with BC. The goal of this study was to identify high-throughput methylation sites (CpG sites) that are associated with three psychoneurological symptoms (ADS) in women with BC. Traditionally, univariate models have been used to examine the relationship between methylation sites and each psychoneurological symptom; nevertheless, ADS can be treated as a cluster of related symptoms and included together in a multivariate linear model. Hence, an overarching goal of this study is to compare and contrast univariate and multivariate models when identifying methylation sites associated with ADS in women with BC. When fitting separate linear regression models for each ADS scale, 3 among 285,173 CpG sites tested were significantly associated with depression. Two significant CpG sites are located on their respective genes FAM101A and FOXJ1, and the third site cannot be mapped to any known gene at this time. In contrast, the multivariate models identified 8,535 ADS-related CpG sites. In conclusion, when analyzing correlated psychoneurological symptom outcomes, multivariate models are more powerful and thus are recommended.

DNA methylation status of epithelial-mesenchymal transition (EMT)--related genes is associated with severe clinical phenotypes in ulcerative colitis (UC)

Background

Epithelial-to-mesenchymal transition (EMT) is a phenomenon that allows the conversion of adherent epithelial cells to a mesenchymal cell phenotype, which enhances migratory capacity and invasiveness. Recent studies have suggested that EMT contributes to the pathogenesis of ulcerative colitis (UC). We investigated the promoter DNA methylation status of EMT-related genes in the colonic mucosa in UC.

Methods

Colonic biopsies were obtained from the rectal inflammatory mucosa of 86 UC patients and the non-inflammatory proximal colonic mucosa of 10 paired patients. Bisulfite pyrosequencing was used to quantify the methylation of 5 candidate CpG island promoters (NEUROG1, CDX1, miR-1247, CDH1, and CDH13) and LINE1.

Results

Using an unsupervised hierarchical clustering analysis, inflamed rectal mucosa was well separated from mucosa that appeared normal. The CDH1 and CDH13 promoters were significantly associated with patient age (p = 0.04, 0.03, respectively). A similar trend was found between those genes and the duration of disease (CDH1: p = 0.07, CDH13: p = 0.0002, mean of both: p<0.00001). Several positive associations were found between hypermethylation and severe clinical phenotypes (CDX1 and miR-1247 and a refractory phenotype: p = 0.04 and 0.006, respectively. miR-1247 and CDH1 hyper methylation and a more severe Mayo endoscopic subscore: miR-1247: p = 0.0008, CDH1: p = 0.03, mean of both: p = 0.003). When the severe clinical phenotype was defined as having any of five phenotypes (hospitalized more than twice, highest Mayo endoscopic subscore, steroid dependence, refractory, or a history of surgery) miR-1247 hypermethylation was associated with the same phenotype (p = 0.008).

Conclusions

Our data suggest that variability in the methylation status of EMT-related genes is associated with more severe clinical phenotypes in UC.