Identification of cuproptosis-related molecular classification and characteristic genes in ulcerative colitis.

Ulcerative colitis (UC) is a refractory inflammatory disease with imbalances in intestinal mucosal homeostasis. Cuproptosis serves as newly identified programmed cell death (PCD) form involved in UC. In the study, UC-related datasets were extracted from the Gene Expression Omnibus (GEO) database. A comparison of UC patients and healthy controls identified 11 differentially expressed cuproptosis-related genes (DE-CRGs), where FDX1, LIAS, and DLAT were differentially expressed in UC groups from the mouse models and clinical samples, with their expression correlating with disease severity. By comprehending weighted gene co-expression network analysis (WGCNA) and differential expression analysis, the key genes common to the module genes relevant to different cuproptosis-related clusters and differentially expressed genes (DEGs) both in different clusters and patients with and without UC were identified using several bioinformatic analysis. Furthermore, the mRNA levels of four characteristic genes with diagnostic potential demonstrated significant decrease in both mouse models and clinical UC samples. Our discoveries offer a theoretical foundation for cuproptosis effect in UC.

Transferrin Is Up-Regulated by Microbes and Acts as a Negative Regulator of Immunity to Induce Intestinal Immunotolerance.

Cross-talks (e.g., host-driven iron withdrawal and microbial iron uptake between host gastrointestinal tract and commensal microbes) regulate immunotolerance and intestinal homeostasis. However, underlying mechanisms that regulate the cross-talks remain poorly understood. Here, we show that bacterial products up-regulate iron-transporter transferrin and transferrin acts as an immunosuppressor by interacting with cluster of differentiation 14 (CD14) to inhibit pattern recognition receptor (PRR) signaling and induce host immunotolerance. Decreased intestinal transferrin is found in germ-free mice and human patients with ulcerative colitis, which are characterized by impaired intestinal immunotolerance. Intestinal transferrin and host immunotolerance are returned to normal when germ-free mice get normal microbial commensalism, suggesting an association between microbial commensalism, transferrin, and host immunotolerance. Mouse colitis models show that transferrin shortage impairs host's tolerogenic responses, while its supplementation promotes immunotolerance. Designed peptide blocking transferrin-CD14 interaction inhibits immunosuppressive effects of transferrin. In monkeys with idiopathic chronic diarrhea, transferrin shows comparable or even better therapeutic effects than hydrocortisone. Our findings reveal that by up-regulating host transferrin to silence PRR signaling, commensal bacteria counteract immune activation induced by themselves to shape host immunity and contribute for intestinal tolerance.

Constructing a prediction model of inflammatory bowel disease recurrence based on factors affecting the quality of life.

Aim: This study aimed to determine the factors affecting the quality of life of patients with inflammatory bowel disease (IBD) and to construct a disease recurrence prediction model based on these influencing factors. Methods: A prospective, single-center study in China was conducted between October 2020 and March 2021. The quality of life of patients was assessed using the Inflammatory Bowel Disease Questionnaire (IBDQ). Multiple stepwise regression analysis was used to analyze the factors influencing the quality of life of patients with IBD. The chi-square test and the point-biserial correlation analysis were performed to identify factors associated with clinical recurrence. A binary logistic regression model was constructed to predict the recurrence. The receiver operating characteristic curve was used to evaluate the prediction model. Patients with IBD from April 2021 to June 2021 were randomly included for model verification to evaluate the disease recurrence prediction model. Results: The average IBDQ score of patients with IBD was 172.2 ± 35.0 (decreased by 23.2%). The scores of all dimensions of the IBDQ were decreased, especially emotional function and systemic symptoms. Disease activity, age, extraintestinal manifestations (EIMs), and annual household income were important factors influencing the IBDQ scores of patients with ulcerative colitis, and these accounted for ~57.0% of the factors affecting the quality of life. Disease activity, EIMs, and occupational stress were important factors influencing the IBDQ scores of patients with Crohn's disease, and they accounted for approximately 75.1% of the factors affecting the quality of life. Annual household income, occupational stress, and IBDQ scores were independent risk factors for recurrence. The area under the curve of the recurrence prediction model was 81.1%. The sensitivity and specificity were 81.7 and 71.7%, respectively. The Youden index of the model was 0.534. The established recurrence prediction model has good discriminant validity in the validation cohort. Conclusion: The quality of life of patients with IBD was generally poor. The use of factors affecting the quality of life to predict disease recurrence has high predictive value and can support the management of IBD by selecting patients at a higher risk for relapse.

Thalidomide combined with endoscopy in the treatment of Cronkhite-Canada syndrome: A case report.

BACKGROUND: Cronkhite-Canada syndrome (CCS) is a rare non-hereditary disease with a poor prognosis and a mortality rate of up to 55%. Currently, there is no standard treatment for CCS. The department of gastroenterology of our hospital admitted a patient with CCS whose symptoms improved significantly after treatment with thalidomide combined with endoscopy, and there was no obvious adverse reaction during the 2-year follow-up. CASE SUMMARY: A 47-year-old Chinese man presented with diarrhea for more than 4 mo, accompanied by loss of taste, fatigue, and weight loss. Physical examination demonstrated that the patient's skin and hands were hyperpigmented, the front edges of the nails of both hands were notably thickened and yellow, and the nails were partially atrophied. Gastrointestinal endoscopy identified a diffuse polypoid bulge, and the patient bore an albumin level of 27.3 g/L. The level of the calcium correction amount was (2.164 mM) which allowed for a comprehensive diagnosis of Cronkhite-Canada syndrome, combined with hypoalbuminemia and hypocalcemia. Thalidomide of 150 mg per day was administered to regulate immunity, and the symptoms were relieved after 1 wk. During the follow-up period, polyps were still found that had not been resolved by thalidomide treatment, and endoscopic therapy was performed. This resulted in further improvement of his condition and no particular discomfort during the 2 years of follow-up. CONCLUSION: The patient's symptoms were significantly relieved by thalidomide 2 years after treatment, proposing it as a potential treatment for CCS.

Rare primary rectal mucosa-associated lymphoid tissue lymphoma with curative resection by endoscopic submucosal dissection: A case report and review of literature.

BACKGROUND: Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) occurs in approximately 9% of non-Hodgkin B-cell lymphomas. The gastrointestinal tract is the most commonly affected site of the extranodal forms of primary non-Hodgkin's lymphomas. However, it rarely occurs within the rectum, and at present, there is no consensus on its diagnosis and treatment at this site. CASE SUMMARY: We report a rare laterally spreading tumour-like rectal MALT lymphoma case in which the diagnosis and the depth of infiltration were determined by magnifying endoscopy and ultrasonic endoscopy. Then, the lesion was en bloc resected by endoscopic submucosal dissection (ESD) alone. The lesion was confirmed as MALT lymphoma by haematoxylin and eosin staining, immunohistochemical staining and gene arrangement analysis. Surveillance exams have indicated a 2-year disease-free survival for this patient. CONCLUSION: We report a rare primary rectal MALT lymphoma that was curable with resection by ESD. ESD is a safe and effective therapeutic option for rectal MALT lymphoma.

Processed Food as a Risk Factor for the Development and Perpetuation of Crohn's Disease-The ENIGMA Study.

(1) Background: Developing countries have experienced a rapid recent rise in Inflammatory Bowel Disease (IBD) incidence and emerging evidence suggests processed foods and food additives may predispose one to the development and perpetuation of Crohn's disease (CD). The aim of this study was to evaluate processed food and food additive intake in CD patients and controls, in Australia (high CD incidence), Hong Kong (intermediate incidence) and mainland China (emerging incidence). (2) Methods: In 274 CD patients (CD), 82 first-degree relatives (FDR), 83 household members (HM) and 92 healthy unrelated controls (HC) from Australia (n = 180), Hong Kong (HK) (n = 160) and mainland China (n = 191) we estimated early life (0-18 years), recent (12 months), and current processed and food additive intake, using validated questionnaires and a 3-day-food diary. (3) Results: Early life processed food intake: Combining all regions, CD were more likely to have consumed soft drinks and fast foods than HM, more likely to have consumed processed fruit and snacks than their FDR, and more likely to have consumed a range of processed foods than HC. HK and China CD patients were more likely to have consumed a range of processed foods than HC. Recent food-additive intake (12-months): Combining all regions, CD patients had significantly higher intakes of aspartame and sucralose, and polysorbate-80, than HC, and more total emulsifiers, artificial sweeteners, and titanium dioxide than FDR and HC. HK and China CD patients had a higher intake of almost all food additives than all controls. Current additive intake (3-days): Australian and HK CD patients had higher total food-additive intake than FDR, and HK CD patients had a higher intake of total food-additives and emulsifiers than HM. (4) Conclusions: CD patients have been exposed to more processed food and food additives than control groups, which may predispose them to CD development and ongoing inflammation.

Childhood antibiotics as a risk factor for Crohn's disease: The ENIGMA International Cohort Study.

Background and Aim: Environmental factors play a key role in development of Crohn's disease (CD), thought to be mediated by changes in the gut microbiota. We aimed to delineate the potential contribution of antibiotic exposure to subsequent development of CD, across diverse geographical populations. Methods: This case-control study in Australia and three cities in China (Hong Kong, Guangzhou, and Kunming) included four groups: patients with CD, at-risk individuals including non-affected first-degree relatives (FDRs) and household members of CD patients (HM), and unrelated healthy controls (HCs). Environmental risk factors, including childhood antibiotic use and 13 other categories, were assessed using a self-developed questionnaire. Logistic regression and conditional logistic regression were used to determine environmental factors associated with CD development. Results: From 2017 to 2019, a total of 254 patients with CD (mean age: 37.98 ± 13.76 years; 58.3% male), 73 FDR (mean age: 49.35 ± 13.28 years; 46.6% male), 122 HMs (including FDR) (mean age: 45.50 ± 13.25 years; 47.5% male), and 78 HC (mean age: 45.57 ± 11.24; 47.4% male) were included. Comparing CD patients with their FDR and HMs, antibiotic use before 18 years old was a risk factor for CD development (adjusted odds ratio [OR] 3.46, 95% confidence interval [CI] 1.38-8.69; P = 0.008). There were no significant differences in other childhood environmental risk factors between CD and their FDR or HMs. Subgroup analysis showed that antibiotic use <18 years old was a risk factor for CD development in the Chinese (adjusted OR 4.80, 95% CI 1.62-12.24; P = 0.005) but not in Australian populations (OR 1.80, 95% CI 0.33-9.95; P = 0.498). Conclusion: Use of antibiotics <18 years was a risk factor for CD development. Attention should be paid to identifying modifiable environmental risk factors in early childhood, especially in at-risk families.

Heat Shock Transcription Factor 2 Promotes Mitophagy of Intestinal Epithelial Cells Through PARL/PINK1/Parkin Pathway in Ulcerative Colitis.

The overactivation of NLRP3 inflammasome in intestinal epithelial cells (IECs) is among the important reasons for severe inflammation in ulcerative colitis (UC). We found that heat shock transcription factor 2 (HSF2), which is highly expressed in UC, could inhibit the activation of NLRP3 inflammasome and reduce IL-1ß in IECs, but the mechanisms were still not clear. It has been reported that HSP72 regulated by HSF2 can enhance the mitophagy mediated by Parkin. The number of damaged mitochondria and the mitochondrial derived ROS (mtROS) can be reduced by mitophagy, which means the activity of NLRP3 inflammasome is inhibited. Therefore, we speculate that HSF2 might regulate the activation of NLRP3 inflammasome of IECs in UC through the mitophagy mediated by Parkin. This study proves that the number of damaged mitochondria in IECs, the level of mitophagy, and the level of ROS in intestinal mucosa are positively correlated with the severity of UC. In mice and cells, mitophagy was promoted by HSF2 through the PARL/PINK1/Parkin pathway. This study reveals the potential mechanisms of HSF2 decreasing mtROS of IECs in UC.

Advances of Heat Shock Family in Ulcerative Colitis.

Ulcerative Colitis (UC) is a non-specific and chronic inflammatory disease of colonic mucosa whose exact etiology and mechanisms remain unclear. The incidence rate of UC is increasing year by year worldwide. What followed is that the medical costs are also rising rapidly. Therefore, it is urgent to understand the pathogenesis and find promising therapeutic targets for UC. Intestinal mucosal homeostasis is essential for normal bowel function, and its imbalance may be an important pathogenesis of UC. Endogenous homeostatic regulators play roles in repairing intestinal mucosa injury after stress. Heat shock family proteins are essential endogenous homeostasis factors. They can inhibit inflammation, regulate intestinal epithelial cells' survival and death, and promote mucosal healing. Thus, they play important roles in sustaining intestinal mucosal homeostasis and protecting against UC progression. However, the heat shock family may promote UC carcinogenesis. Here, we summarize the advances in the research of the functions of the heat shock family in UC. And this review is an attempt to light on the etiopathogenesis of UC, highlighting the endogenous protective mechanisms, hoping to provide a novel therapeutic target for UC treatment.

Keratin 1 maintains the intestinal barrier in ulcerative colitis.

BACKGROUND: The intestinal mechanical barrier plays a key role in the pathogenesis of ulcerative colitis (UC). Our previous study showed keratin 1 (KRT1) was downregulated in UC, but the mechanism by which KRT1 affects the intestinal barrier remains unknown. OBJECTIVES: To explore the mechanism of KRT1 in the intestinal barrier in UC. METHODS: Colonic tissues were collected from 20 UC patients before and after mucosal healing (MH) and 15 healthy controls. The expression of KRT1 was measured by PCR, western blotting and immunohistochemistry (IHC). A dextran sulfate sodium (DSS)-induced colitis model was established in krt1 transgenic (TG) mice, and the mice were treated with methylprednisolone (MP) to explore the role of KRT1 in the intestinal barrier. Inflammation was evaluated through the DAI score, colon, spleen and H&E. The expression of KRT1 and tight junction (TJ) proteins in mouse was analysed by the same methods. RESULTS: The transcription and expression of KRT1 in UC was decreased and recovered after MH but did not reach the level of the healthy controls. Similar to the clinical results, the expression of krt1 was decreased in DSS-induced colitis and upregulated after MP. Moreover, the krt1 TG group exhibited less inflammation than wild-type (WT) group. The expression of Occludin and ZO-1 decreased after DSS induction, the decreases in Occludin and ZO-1 in the krt1 TG group were lower than WT group, which was significantly increased after MP, while the expression of Claudin-2 exhibited the opposite effect. CONCLUSIONS: Keratin 1 maintains the intestinal barrier by upregulating TJ proteins in UC.

Alterations in the Gut Virome in Obesity and Type 2 Diabetes Mellitus.

BACKGROUND & AIMS: Obesity and type 2 diabetes mellitus (T2DM) are associated with changes in the gut bacterial composition, but little is known about the role of the viral community (virome) in disease development. This study aims to characterize the gut virome alterations in obese subjects with or without T2DM. METHODS: There were 128 obese subjects (body mass index ≥28 kg/m2) and 101 lean controls (body mass index ≥18.5 and <23 kg/m2) recruited from 2 regions in China (Hong Kong and Kunming). Fecal virome and bacteriome were profiled by shotgun metagenomic sequencing. Gut virome, bacteriome, and viral-bacterial correlations were compared between obese subjects and lean controls. RESULTS: Obese subjects, especially those with T2DM (ObT2), had a decreased gut viral richness and diversity compared with lean controls in the Hong Kong cohort (P < .05), while no significant differences were observed in the Kunming cohort. Eleven viruses, including Escherichia phage, Geobacillus phage, and Lactobacillus phage were enriched in obese subjects (q < .1). Besides, 17 differentially abundant viruses were identified between ObT2 and lean controls (q < .1). Further ecologic analysis revealed that intensive transkingdom correlations between viruses and bacteria observed in lean controls were significantly decreased in ObT2 subjects (P < .001). CONCLUSIONS: Obesity is characterized by altered viral taxonomic composition and weakened viral-bacterial correlations compared with lean controls. Obesity accompanied with T2DM may aggravate the obesity-associated virus signatures, signifying that the gut virome may play an important role in the development of obesity and T2DM. Geographic factors also contributed to the variations of gut virome in obesity and T2DM.

Ecological and network analyses identify four microbial species with potential significance for the diagnosis/treatment of ulcerative colitis (UC).

BACKGROUND: Ulcerative colitis (UC) is one of the primary types of inflammatory bowel disease (IBD), the occurrence of which has been increasing worldwide. Although IBD is an intensively studied human microbiome-associated disease, research on Chinese populations remains relatively limited, particularly on the mucosal microbiome. The present study aimed to analyze the changes in the mucosal microbiome associated with UC from the perspectives of medical ecology and complex network analysis. RESULTS: In total, 56 mucosal microbiome samples were collected from 28 Chinese UC patients and their healthy family partners, followed by amplicon sequencing. Based on sequencing data, we analyzed species diversity, shared species, and inter-species interactions at the whole community, main phyla, and core/periphery species levels. We identified four opportunistic "pathogens" (i.e., Clostridium tertium, Odoribacter splanchnicus, Ruminococcus gnavus, and Flavonifractor plautii) with potential significance for the diagnosis and treatment of UC, which were inhibited in healthy individuals, but unrestricted in the UC patients. In addition, we also discovered in this study: (i) The positive-to-negative links (P/N) ratio, which measures the balance of species interactions or inhibition effects in microbiome networks, was significantly higher in UC patients, indicating loss of inhibition against potentially opportunistic "pathogens" associated with dysbiosis. (ii) Previous studies have reported conflicting evidence regarding species diversity and composition between UC patients and healthy controls. Here, significant differences were found at the major phylum and core/periphery scales, but not at the whole community level. Thus, we argue that the paradoxical results found in existing studies are due to the scale effect. CONCLUSIONS: Our results reveal changes in the ecology and network structure of the gut mucosal microbiome that might be associated with UC, and these changes might provide potential therapeutic mechanisms of UC. The four opportunistic pathogens that were identified in the present study deserve further investigation in future studies.

Heat shock transcription factor 2 reduces the secretion of IL-1ß by inhibiting NLRP3 inflammasome activation in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory disease with unknown aetiology. As a pro-inflammatory cytokine, interleukin-1ß (IL-1ß) plays a critical, damaging role in UC. Heat shock proteins (HSPs) are important anti-inflammatory factors that maintain intestinal epithelial cells (IECs) homeostasis. Heat shock transcription factor 2 (HSF2) is an important regulator of HSPs. In our previous research, we found that HSF2 is highly expressed in UC, is negatively related to colon inflammation of mice, and inhibits the expression of IL-1ß, but the specific mechanism is still unclear. As a product of the NLRP3 inflammasome, the expression of IL-1ß is closely related to NLRP3 inflammasome activation. Therefore, we hypothesised that HSF2 affects the secretion of IL-1ß by regulating activation of the NLRP3 inflammasome. In this study, hsf-/- DSS model mice showed highest levels of expression of the NLRP3 inflammasome and the secretion of IL-1ß. In Caco-2 cells, the levels of expression of the NLRP3 inflammasome and the secretion of IL-1ß were inhibited by overexpression of HSF2, and inhibited HSF2 increased activation of the NLRP3 inflammasome and the secretion of IL-1ß. These findings indicated that HSF2 might be an important target for inflammatory modulation in UC.

Population-Level Configurations of Gut Mycobiome Across 6 Ethnicities in Urban and Rural China.

BACKGROUND & AIMS: Beyond bacteria, the human gastrointestinal tract is host to a vast diversity of fungi, collectively known as the gut mycobiome. Little is known of the impact of geography, ethnicity, and urbanization on the gut mycobiome at a large population level. We aim to delineate the variation of human gut mycobiome and its association with host factors, environmental factors, and diets. METHODS: Using shotgun metagenomic sequencing, we profiled and compared the fecal mycobiome of 942 healthy individuals across different geographic regions in China (Hong Kong and Yunnan), spanning 6 ethnicities: Han, Zang, Bai, Hani, Dai, and Miao (including both urban and rural residents of each ethnicity). In parallel to fecal sampling, we collected participant metadata (environmental exposure, bowel habits, anthropometrics, and medication), diet, and clinical blood measurement results (a total of 118 variables) and investigated their impact on the gut mycobiome variation in humans. RESULTS: The human gut mycobiome was highly variable across populations. Urbanization-related factors had the strongest impact on gut mycobiome variation, followed by geography, dietary habit, and ethnicity. The Hong Kong population (highly urbanized) had a significantly lower fungal richness compared with Yunnan population. Saccharomyces cerevisiae was highly enriched in urban compared with rural populations and showed significant inverse correlations with liver pathology-associated blood parameters, including aspartate transaminase, alanine transaminase, gamma-glutamyltransferase, and direct bilirubin. Candida dubliniensis, which was decreased in urban relative to rural populations, showed correlations with host metabolism-related parameters in blood, including a positive correlation with fasting high-density lipoprotein cholesterol levels and a negative correlation with fasting glucose levels. The fungal-blood parameter correlations were highly geography- and ethnicity-specific. Food choices had differential influences on gut mycobiome and bacterial microbiome, where taxa from the same genus tended to be coregulated by food and thereby cobloom. Ethnicity-specific fungal signatures were associated with distinct habitual foods in each ethnic group. CONCLUSIONS: Our data highlight, for the first time to our knowledge, that geography, urbanization, ethnicity, and habitual diet play an important role in shaping the gut mycobiome composition. Gut fungal configurations in combination with population characteristics (such as residing region, ethnicity, diet, lifestyle) influence host metabolism and health.

Does Ulcerative Colitis Influence the Inter-individual Heterogeneity of the Human Intestinal Mucosal Microbiome?

The dysbiosis of the gut microbiome associated with ulcerative colitis (UC) has been extensively studied in recent years. However, the question of whether UC influences the spatial heterogeneity of the human gut mucosal microbiome has not been addressed. Spatial heterogeneity (specifically, the inter-individual heterogeneity in microbial species abundances) is one of the most important characterizations at both population and community scales, and can be assessed and interpreted by Taylor's power law (TPL) and its community-scale extensions (TPLEs). Due to the high mobility of microbes, it is difficult to investigate their spatial heterogeneity explicitly; however, TPLE offers an effective approach to implicitly analyze the microbial communities. Here, we investigated the influence of UC on the spatial heterogeneity of the gut microbiome with intestinal mucosal microbiome samples collected from 28 UC patients and healthy controls. Specifically, we applied Type-I TPLE for measuring community spatial heterogeneity and Type-III TPLE for measuring mixed-species population heterogeneity to evaluate the heterogeneity changes of the mucosal microbiome induced by UC at both the community and species scales. We further used permutation test to determine the possible differences between UC patients and healthy controls in heterogeneity scaling parameters. Results showed that UC did not significantly influence gut mucosal microbiome heterogeneity at either the community or mixed-species levels. These findings demonstrated significant resilience of the human gut microbiome and confirmed a prediction of TPLE: that the inter-subject heterogeneity scaling parameter of the gut microbiome is an intrinsic property to humans, invariant with UC disease.

Heat shock transcription factor 2 predicts mucosal healing and promotes mucosal repair of ulcerative colitis.

Background: Mucosal healing(MH) is a treatment goal in ulcerative colitis (UC). Our previous studies showed heat shock transcription factor 2 (HSF2) was positively correlated with the activity of UC and had anti-inflammatory potential in DSS-induced colitis, but the role of HSF2 in MH remains unknown. This study aimed to reveal the predictive value and mechanisms of HSF2 in the MH of UC.Methods: Fecal samples were collected from 51 UC patients and 10 healthy controls. Correlation analyses among HSF2, fecal calprotectin(FC) and Mayo endoscopic subscore(MES) were conducted by Pearson correlation coefficient. Diagnostic accuracy and cutoffs to predict MH were analyzed by ROC curves. 231 UC patients were enrolled to verify the diagnostic validity of the cutoffs. HSF2 siRNA and HSF2-FLAG recombinant plasmids were transfected into HT-29 cells. IL-1ß, TNF-α and TGF-ß levels in supernatants were determined by ELISA. The expression and phosphorylation levels of MAPKs and Smad2/3 were detected by Western blotting.Results: Positive correlations existed between HSF2 and MES (r = 0.81), FC and MES (r = 0.85), and HSF2 and FC (r = 0.91). Optimal cutoffs of HSF2 was 1.97 ng/ml (AUC 0.919) and that of FC was 678 µg/g (AUC 0.958). HSF2 and FC achieved high sensitivity (73.7% vs 84.2%) and negative predictive value (89.1% vs 93.9%). HSF2 decreased IL-1ß and TNF-α secretion via suppression of MAPK signaling pathway activation. HSF2 promoted the expression of TGF-ß via increasing phosphorylation of Smad2/3.Conclusions: HSF2 may be a predictor of MH in UC patients. HSF2 inhibited inflammation and promoted mucosal repair.

Heat shock transcription factor 2 inhibits intestinal epithelial cell apoptosis through the mitochondrial pathway in ulcerative colitis.

UC is a chronic inflammatory disease of the colonic mucosa and lacks effective treatments because of unclear pathogenesis. Excessive apoptosis of IECs damages the intestinal epithelial barrier and is involved in the progression of UC, but the mechanism is unknown. HSPs are important in maintaining homeostasis and regulate apoptosis through the mitochondrial pathway. In our previous studies, HSF2, an important regulator of HSPs, was highly expressed in UC patients and negatively correlated with inflammation in mice and IECs. Therefore, we hypothesized that HSF2 may protect against intestinal mucositis by regulating the apoptosis of IECs. In this study, a DSS-induced colitis model of hsf2-/- mice was used to explore the relationship between HSF2 and apoptosis in IECs for the first time. The expression of HSF2 increased in the WT + DSS group compared with that in the WT + H2O group. Moreover, the extent of apoptosis was more severe in the KO + DSS group than in the WT + DSS group. The results showed that HSF2 was negatively correlated with apoptosis in vivo. The expression of HSF2 in Caco-2 cells was changed by lentiviral transfection, and the expression of Bax, cytoplasmic Cyto-C, Cleaved Caspase-9 and Cleaved Caspase-3 were negatively correlated with the different levels of HSF2. These results suggest that HSF2 negatively regulates apoptosis of IECs through the mitochondrial pathway. This may be one of the potential mechanisms to explain the protective role of HSF2 in UC.

Heat-shock transcription factor 2 promotes sodium butyrate-induced autophagy by inhibiting mTOR in ulcerative colitis.

Butyrate-induced autophagy and anti-inflammatory effects of IECs plays an important role in UC. HSP has been proved to be associated with autophagy. HSF2, as an important regulator of HSP, has been determined to be highly expressed in UC. This study was designed to elucidate the relationship between HSF2, butyrate and epithelial autophagy and the potential mechanism of HSF2-related autophagy in UC. The autophagy levels and HSF2 expression in intestinal mucosa were increased in UC patients compared to controls. In DSS colitis models, hsf2-/- mice exhibited more severe intestinal inflammation and lower autophagy levels than wild-type mice. HSF2 expression could be induced by sodium butyrate and LPS as a dose-response relationship in HT-29 cells, epigenetically via increasing histone acetylation levels at the promoter region by sodium butyrate. Autophagy induced by sodium butyrate was promoted by overexpression HSF2 in HT-29 cells. Moreover, overexpression HSF2 decreased the expression and phosphorylation levels of PI3K, Akt and mTOR induced by sodium butyrate. HSF2 might induced by sodium butyrate and inflammation and played protective roles in UC by enhancing autophagy of IECs. This indicated that HSF2 may be a critical target for autophagy modulation and a new potential therapeutic target in UC.

Differential expression of serum microRNAs in glucocorticoid-resistant patients with ulcerative colitis.

Inflammatory bowel disease (IBD) includes ulcerative colitis (UC) and Crohn's disease (CD). Glucocorticoids (GCs) are the most effective treatment for moderate to severe active UC. However, one-third of patients are not sensitive to GCs (i.e., they are GC resistant). The mechanism of GC resistance in IBD is unknown, and it remains unclear how to predict resistance in IBD patients. This study aimed to explore the possible correlation between miRNA expression and variability in GC-resistant and GC-sensitive patients with ulcerative colitis. A comparative serum microRNA analysis in GC-resistant and GC-sensitive patients with ulcerative colitis was conducted by microarray. Differential microRNA expression was further validated in serum samples by quantitative real-time PCR. We found that downregulated microRNAs had a significant correlation with several signal transduction pathways (the PI3K-Akt and MAPK signaling pathways) and target genes (HSP90B1, MAPK13, MAPK9, PIK3AP1 and TLR4) related to GC resistance. Eight downregulated microRNAs were chosen for further validation in 76 serum samples. The results showed that miR-16-2-3p, miR-30e-3p, miR-32-5p, miR-642a-5p, miR-150-5p, and miR-224-5p were significantly downregulated in the GC-resistant group. Receiver operating characteristic analysis showed that the area under the curves (AUCs) for those microRNAs were 0.94, 0.93, 0.85, 0.87, 0.92, and 0.99, with specificities of 97.30%, 89.20%, 59.50%, 73.00%, 97.30%, and 97.30% and sensitivities of 74.40%, 84.60%, 97.40%, 92.30%, 66.70%, and 89.70%, respectively. Our study provides preliminary evidence for the pathogenic mechanism of GC resistance and shows that serum microRNAs might serve as biomarkers for GC resistance in IBD.

Antimicrobial peptide LL-37 forms complex with bacterial DNA to facilitate blood translocation of bacterial DNA and aggravate ulcerative colitis.

Bacterial DNA (bacDNA) is frequently found in serum of patient with ulcerative colitis (UC) and Crohn's disease, even blood bacterial culture is negative. How bacDNA evades immune elimination and is translocated into blood remain unclear. Here, we showed that bacDNA avoids elimination and disables bacteria-killing function of antimicrobial peptide LL-37 (Cramp in mice) by forming complex with LL-37, which is inducible after culture with bacteria or bacterial products. Elevated LL-37-bacDNA complex was found in plasma and lesions of patients with UC. LL-37-bacDNA promoted inflammation by inducing Th1, Th2 and Th17 differentiation and activating toll-like receptor-9 (TLR9). The complex also increased paracellular permeability, which possibly combines its inflammatory effects to promote local damage and bacDNA translocation into blood. Cramp-bacDNA aggravated mouse colitis severity while interference with the complex ameliorated the disease. The study identifies that inflammatogenic bacDNA utilizes LL-37 as a vehicle for blood translocation and to evade immune elimination. Additionally, bacteria may make a milieu by releasing bacDNA to utilize and resist host antimicrobial peptides as a 'trojan horse'.