Project description:Non-steroidal anti-inflammatory drugs (NSAIDs) are used extensively as therapeutic agents, despite their well-documented gastrointestinal (GI) toxicity. Presently, the mechanisms responsible for NSAID-associated GI damage are incompletely understood. In this study, we used Microarray analysis to generate a novel hypothesis about cellular mechanisms that underlie the GI toxicity of NSAIDs. Monolayers of intestinal epithelial; cells (IEC-6) were treated with NSAIDs that either exhibit indomethacin, NS-398) or lack (SC-560) inhibitory effects on intestinal epithelial cell migration. Bioinformatic analysis of array data suggested that NSAIDs with adverse GI effects either decrease the gene expression of the calpains or increase the gene expression of the calpain engodenous; inhibitor, calpastatin. Calpains have been shown previously to modulate the migration of a variety of cells in different physiological contexts. Our experimental results suggest that the altered expression of calpain genes may contribute to the adverse effects of NSAIDs on intestinal; epithelial restitution. Microarray analysis has generated the novel hypothesis that the GI toxicity of NSAIDs may be attributed in part to drug-induced changes in the expression and activity of calpains. Experiment Overall Design: Monolayers of intestinal epithelial cells (IEC-6) were treated with NSAIDs that either exhibit (indomethacin, NS-398) or lack (SC-560) inhibitory effects on intestinal epithelial cell migration. Samples were then pooled to obtain sufficient material for gene array analysis. The pooled samples were used to hybridize 4 gene array chips for each biological sample.
Project description:Non-steroidal anti-inflammatory drugs (NSAIDs) are used extensively as therapeutic agents, despite their well-documented gastrointestinal (GI) toxicity. Presently, the mechanisms responsible for NSAID-associated GI damage are incompletely understood. In this study, we used Microarray analysis to generate a novel hypothesis about cellular mechanisms that underlie the GI toxicity of NSAIDs. Monolayers of intestinal epithelial cells (IEC-6) were treated with NSAIDs that either exhibit indomethacin, NS-398) or lack (SC-560) inhibitory effects on intestinal epithelial cell migration. Bioinformatic analysis of array data suggested that NSAIDs with adverse GI effects either decrease the gene expression of the calpains or increase the gene expression of the calpain engodenous inhibitor, calpastatin. Calpains have been shown previously to modulate the migration of a variety of cells in different physiological contexts. Our experimental results suggest that the altered expression of calpain genes may contribute to the adverse effects of NSAIDs on intestinal epithelial restitution. Microarray analysis has generated the novel hypothesis that the GI toxicity of NSAIDs may be attributed in part to drug-induced changes in the expression and activity of calpains. Keywords: dose response
Project description:To explore the effect of butyrate on intestinal epithelial cells in collagen-induced arthritis (CIA) mouse model, we conducted Single-Cell RNA Sequencing profiling of intestinal tissue in response to butyrate treatment.
Project description:The balance between tolerogenic and inflammatory responses determines immune homeostasis in the gut. Dysbiosis and a defective host defense against invading intestinal bacteria can shift this balance via bacterial-derived metabolites and trigger chronic inflammation. We show that the short chain fatty acid butyrate modulates monocyte to macrophage differentiation by promoting antimicrobial effector functions. The presence of butyrate modulates antimicrobial activity via a shift in macrophage metabolism and reduction in mTOR activity. This mechanism is furthermore dependent on the inhibitory function of butyrate on histone deacetylase 3 (HDAC3) driving transcription of a set of antimicrobial peptides including calprotectin. The increased antimicrobial activity against several bacterial species is not associated with increased production of conventional cytokines. Butyrate imprints antimicrobial activity of intestinal macrophages in vivo. Our data suggest that commensal bacteria derived butyrate stabilize gut homeostasis by promoting antimicrobial host defense pathways in monocytes that differentiate into intestinal macrophages.
Project description:Intestinal epithelial cells and the intestinal microbiota are in a mutualistic relationship that is dependent on communication. This communication is multifaceted, but one aspect is communication through compounds produced by the microbiota such as the short-chain fatty acids (SCFAs) butyrate, propionate and acetate. Studying the effects of SCFAs and especially butyrate in intestinal epithelial cell lines like Caco-2 cells has been proven problematic. In contrast to the in vivo intestinal epithelium, Caco-2 cells do not use butyrate as an energy source, leading to a build-up of butyrate. Therefore, we used human induced pluripotent stem cell derived intestinal epithelial cells, grown as a cell layer, to study the effects of butyrate, propionate and acetate on whole genome gene expression in the cells. For this, cells were exposed to concentrations of 1 and 10 mM of the individual short-chain fatty acids for 24 hours. Unique gene expression profiles were observed for each of the SCFAs in a concentration-dependent manner. Evaluation on both an individual gene level and pathway level showed that butyrate induced the biggest effects followed by propionate and then acetate. Several known effects of SCFAs on intestinal cells were confirmed, such as effects on metabolism and immune responses. The changes in metabolic pathways in the intestinal epithelial cell layers in this study demonstrate that there is a switch in energy source from glucose to SCFAs, thus induced pluripotent stem cell derived intestinal epithelial cell are responding in a similar manner to SCFAs as in vivo intestinal tissues.
Project description:The intestinal epithelium senses and responds to the myriad of signals from gut microbiota, but it remains unclear how these signals are integrated to drive physiological responses. In this work, we found that enterochromaffin (EC) cells in the gut serve as signal integration hubs for microbial metabolites. EC cells coordinate responses to combinations of microbial metabolites, resulting in complex alterations in serotonin signaling that drive changes in GI physiology. We found that microbial metabolites either directly trigger responses or alter the expression of receptors for other microbial metabolites in EC cells. The microbiota-derived purine derivative hypoxanthine triggers a signaling pathway by activating G-protein coupled receptor A1R, which in turn activates the calcium channel TRPC4, resulting in increased serotonin release and accelerated GI transit. On the other hand, bacteria-derived butyrate does not evoke EC cell calcium influx by itself, but drives epigenetic changes that upregulate TRPC4 expression, thereby enhancing response to metabolites like hypoxanthine and norepinephrine that act via TRPC4. Since the expression TRPC4 is limited to EC cells, these cells function as specialized epithelial sensors that integrate signals from regulatory (butyrate) and effector metabolites like hypoxanthine and norepinephrine. These findings offer new microbiota-driven therapeutic avenues for conditions associated with altered GI function.
Project description:Gut bacterial β-glucuronidases (GUS) promote the toxic side effects of therapeutics by reactivating drugs from their inactive glucuronide conjugates. It is increasingly clear that the interindividual variability of bacterial GUS-producing species in the gut microbiota contributes to differential drug responses. Indeed, the anticancer drug irinotecan exhibits variable clinical toxicity outcomes that have been linked to interindividual differences in the composition of the gut microbiota. However, identification of the specific GUS enzymes responsible for drug metabolism in the context of the complexity of the human fecal microbiota has not been achieved. Here we pinpoint the specific bacterial GUS enzymes that reactivate SN-38, the active metabolite of irinotecan, from complex human fecal microbiota samples with activity-based protein profiling (ABPP). We identify and quantify gut bacterial GUS enzymes from human feces with ABPP-enabled proteomics and then integrate this information with ex vivo kinetics to reveal the specific GUS enzymes responsible for the reactivation of SN-38. The same ABPP approach also reveals the molecular basis for differential gut bacterial GUS inhibition between human fecal samples. Taken together, this work provides an unprecedented pipeline to identify the specific bacterial GUS enzymes responsible for drug-induced GI toxicity from the complexity of human feces, which may serve as highly precise biomarkers of clinical outcomes for irinotecan and other therapeutics.
Project description:A growing body of evidence suggests that particulate matter (PM10) enters the gastrointestinal (GI) tract directly, causing the GI epithelial cells to function less efficiently, leading to inflammation and an imbalance in the gut microbiome. PM10 may, however, act as an exacerbation factor in patients with inflamed intestinal epithelium, which is associated with inflammatory bowel disease. In this study, we established chronically inflamed intestinal epithelium models utilizing two-dimensional (2D) human intestinal epithelial cells (hIECs) and 3D human intestinal organoids (hIOs), which mimic in vivo cellular diversity and function, in order to examine the deleterious effects of PM10 in human intestine-like in vitro models. Inflamed 2D hIECs and 3D hIOs exhibited pathological features, such as inflammation, decreased intestinal markers, and defective epithelial barrier function. In addition, we found that PM10 exposure induced a more severe disturbance of peptide uptake in inflamed 2D hIECs and 3D hIOs than in control cells. This was due to the fact that it interferes with calcium signaling, protein digestion, and absorption pathways. The findings demonstrate that PM10-induced epithelial alterations contribute to the exacerbation of inflammatory disorders caused by the intestine. According to our findings, 2D hIEC and 3D hIO models could be powerful in vitro platforms for the evaluation of the causal relationship between PM exposure and abnormal human intestinal functions.
Project description:Caudal type homeobox 2 (CDX2) is a transcription factor expressed in the gastrointestinal (GI) epithelial (IEC) and stromal cells .CDX2 along with APC can regulate Lgr5 intestinal stem cell (ISC) differentiation to control GI tract development or intestinal neoplasia. CDX2 or APC loss function is associated with colorectal cancer (CRC) advance. However, whether APC directly regulates CRC metastasis is not clear. We aim to determine the role of inactive Apc gene in Cdx2 GI cells on Lgr5 ISC metastasis.
Project description:Mycophenolate mofetil (MMF) has been widely prescribed for neuromyelitis optica spectrum disorders (NMOSD) although some patients experience severe gastrointestinal (GI) side effects following MMF administration. Our study investigated the potential mechanisms of this toxicity in NMOSD patients. We constructed MMF-induced colitis mouse model and produced a multi-omic dataset in which microbiome and metabolome analysis from the mouse GI tract to decipher the mechanisms of MMF GI toxicity. Further, 17 female NMOSD patients treated with MMF were prospectively enrolled and grouped according to the diarrhea symptom as non-diarrhea NMOSD group (NM) and diarrhea NMOSD group (DNM) as well as healthy controls (HC, 12 female). The gut microbiota was analyzed using 16S rRNA sequencing of stool samples. In the mouse model, we found that vancomycin administration drastically altered the colon content metabolomes and microbiomes and prevented MMF-induced body weight loss, cecal and colon tissue injury. Bacteroidetes and Firmicutes converted phenyl-beta-D-glucuronide (MPAG) to mycophenolic acid (MPA) that could result in damaged intestinal tissue. We also demonstrated that the alpha diversity in the DNM group was increased and this was accompanied by increased Firmicutes and Proteobacteria abundance. Collectively, these results reveal that alterations of the gut microbiome and metabolome contribute to MMF-induced colitis. Modifying of the gut microbiome and metabolome may alleviate MMF-induced GI toxicity in NMOSD patients.