Project description:BACKGROUND: Appendicitis followed by appendectomy (AA) at a young age protects against later inflammatory bowel disease (IBD). Using a novel murine appendicitis model we earlier demonstrated that AA proffered significant protection against subsequent experimental colitis. AIM: To delineate genes and biological pathways involved in the protective effect of AA against subsequent colitis using gene set enrichment analysis (GSEA) of DNA microarray data. METHODS: Appendicitis and appendicectomy was done (5 week old male BALB/c mice) near the most proximal colon (caecal lymphoid follicles) and colonic samples were harvested from the most distal colon. Two consecutive laparotomies were done in control Sham-Sham (SS) mice. RNA was extracted (TRIzol®) from 4 individual colonic samples per group (AA group vs. SS group) with each sample taken independently through Affymetrix® microarray hybridization. For GSEA, data for more than 23,000 genes were exported from Partek and analyzed with GSEA software (with 2852 gene sets encoded) to establish correlates with phenotypes of the gene sets. RESULTS: Distal colonic expression of 636 gene-sets were significantly upregulated in AA group samples (False Discovery Rates (FDR) values < 1 % and p value < 0.001; stringent statistical selection). These were validated by quantitative PCR of 14 selected genes across the immunological spectrum and over time-intervals of 3 days, 14 days and 28 days. CONCLUSIONS: Many key immunological, apoptosis-related and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. Further analysis of these profiles and biological pathways will assist utilizing these gene products and manipulating various aspects of these pathways to develop better therapeutic strategies in the management of intractable IBD. Appendicitis and appendicectomy was done (5 week old male BALB/c mice) near the most proximal colon (caecal lymphoid follicles) and colonic samples were harvested from the most distal colon. Two consecutive laparotomies were done in control Sham-Sham (SS) mice. RNA was extracted (TRIzol®) from 4 individual colonic samples per group (AA group vs. SS group) with each sample taken independently through Affymetrix® microarray hybridization. variable_protocol: appendicitis and appendectomy: AA1, AA2, AA3, AA4 variable_protocol: sham/sham surgery: SS1, SS2, SS3, SS4 repeat_biological replicate: AA1, AA2, AA3, AA4 repeat_biological replicate: SS1, SS2, SS3, SS4 Upregulated gene-set linked as supplementary file.
Project description:BACKGROUND: Appendicitis followed by appendectomy (AA) at a young age protects against later inflammatory bowel disease (IBD). Using a novel murine appendicitis model we earlier demonstrated that AA proffered significant protection against subsequent experimental colitis. AIM: To delineate genes and biological pathways involved in the protective effect of AA against subsequent colitis using gene set enrichment analysis (GSEA) of DNA microarray data. METHODS: Appendicitis and appendicectomy was done (5 week old male BALB/c mice) near the most proximal colon (caecal lymphoid follicles) and colonic samples were harvested from the most distal colon. Two consecutive laparotomies were done in control Sham-Sham (SS) mice. RNA was extracted (TRIzol®) from 4 individual colonic samples per group (AA group vs. SS group) with each sample taken independently through Affymetrix® microarray hybridization. For GSEA, data for more than 23,000 genes were exported from Partek and analyzed with GSEA software (with 2852 gene sets encoded) to establish correlates with phenotypes of the gene sets. RESULTS: Distal colonic expression of 636 gene-sets were significantly upregulated in AA group samples (False Discovery Rates (FDR) values < 1 % and p value < 0.001; stringent statistical selection). These were validated by quantitative PCR of 14 selected genes across the immunological spectrum and over time-intervals of 3 days, 14 days and 28 days. CONCLUSIONS: Many key immunological, apoptosis-related and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. Further analysis of these profiles and biological pathways will assist utilizing these gene products and manipulating various aspects of these pathways to develop better therapeutic strategies in the management of intractable IBD.
Project description:Transcription profiling by array of mice which have undergone appendicitis followed by appendectomy (AA) at a young age against those with sham surgery to study the potential protective effect of AA against inflammatory bowel disease
Project description:We unveiled the disease relevance of the C. rodentium induced colitis model to IBD and demonstrated the protective role of the mucosal healing therapy IL-22.Fc in ameliorating the epithelial dysfunction
Project description:Transcription profiling of patients with four neurodegenerative disorders distinguishes tauopathies and identifies shared molecular pathways
Project description:Ulcerative colitis (UC), a form of inflammatory bowel disease, is characterized by a Q7 recurrent and persistent nonspecific inflammatory response. Polydatin (PD), a natural stilbenoid polyphenol with potent properties, exhibits unexpected beneficial effects beyond its well-documented anti-inflammatory and antioxidant activities. In this study, we presented evidence that PD confers protection against dextran sodium sulfate (DSS)-induced ulcerative colitis. Our findings demonstrated that PD mitigated the DSS-induced increases in proinflammatory cytokines (IL-6, TNF-α, and IL-1β), alleviated colon length shortening, reduced morphological damage to the intestinal mucosa, and preserved tight junction proteins (TJ) occludin and Zonula occludens-1 (ZO-1) in both Caco-2 cells and murine models of colitis. Results from bulk RNA sequencing and differential gene analysis suggested a potential role for ferroptosis in the protective mechanisms of PD against UC. Further investigations revealed that PD modulated the expression levels of several ferroptosis-related proteins and transcription factors within the DSS-induced colitis model. Notably, treatment with PD enhanced nuclear translocation of Nrf2, which inhibits ferroptosis while ameliorating oxidative stress through upregulation of Slc7a11 and Gpx4 expression. Additionally, erastin—a known inducer of ferroptosis—reversed the protective effects conferred by PD in the DSS-induced colitis model by downregulating Slc7a11 expression. These findings underscore that PD protects against DSS-induced ulcerative colitis via the Nrf2/ Slc7a11/Gpx4 signaling axis, highlighting its potential as a novel therapeutic agent for UC.
Project description:Background: The diagnosis of acute appendicitis can be surprisingly difficult without computed tomography, which carries significant radiation exposure. Genome-wide expression profiling was applied to whole blood RNA of acute appendicitis patients versus patients with other abdominal disorders, in order to identify biomarkers of appendicitis. From a large cohort of emergency patients, a discovery set of patients with surgically confirmed appendicitis, or abdominal pain from other causes, was identified. RNA from whole blood was profiled by microarrays, and RNA levels were filtered by a combined fold-change (>2) and p value (<0.05). A separate set of patients, including patients with respiratory infections, was used to validate a partial least squares discriminant (PLSD) prediction model. Results: Transcript profiling identified 37 differentially expressed genes (DEG) in appendicitis versus abdominal pain patients. The DEG list contained 3 major ontologies: infection-related, inflammation-related, and ribosomal processing. Appendicitis patients had lower level of neutrophil defensin mRNA (DEFA1,3), but higher levels of alkaline phosphatase (ALPL) and interleukin-8 receptor-ß (IL8RB), which was confirmed in a larger cohort of 60 patients using droplet digital PCR (ddPCR). Conclusions: Patients with acute appendicitis have detectable changes in the mRNA expression levels of factors related to neutrophil inate defense systems. The low defensin mRNA levels suggest that appendicitis patient's immune cells are not directly activated by pathogens, but are primed by diffusible factors in the microenvironment of the infection. The detected biomarkers are consistent with prior evidence that biofilm-forming bacteria in the appendix may be an important factor in appendicitis.
Project description:Appendicitis is the most common condition necessitating emergency abdominal surgery. While most cases are localized, 20% are complicated and result in appendix perforation. The management of non-complicated appendicitis varies across different medical centers, encompassing both surgical and non-surgical options, whereas complicated appendicitis is predominantly managed surgically. Differentiating them poses a clinical challenge, especially in pediatric patients, crucial for guiding appropriate treatment strategies. Therefore, there is an unmet need for biomarkers to distinguish the two entities. Here we examined the utility of epigenetic liquid biopsies in appendicitis. We used DNA methylation markers specific to immune and gastrointestinal epithelial cells to assess the tissue origins of plasma cell-free DNA (cfDNA) in patients with appendicitis. Appendix epithelium cfDNA was not detected in plasma samples from children with appendicitis relative to patients with abdominal pain and controls. In contrast, neutrophil and regulatory T-cell cfDNA were elevated in appendicitis enhancing the specificity and sensitivity of appendicitis diagnosis beyond the information provided by neutrophil counts. Notably, eosinophil cfDNA was most significantly elevated in children with perforated compared with non-perforated appendicitis. This finding was cross-validated using a machine-learning approach. In conclusion, eosinophil cfDNA can serve as a non-invasive biomarker for diagnosing perforated appendicitis.