Cleavage of E-Cadherin Contributes to Defective Barrier Function in Neosquamous Epithelium

After ablation of Barrett’s esophagus (BE), the esophagus heals with neosquamous epithelium (NSE). Despite normal endoscopic appearance, NSE exhibits defective barrier function with similarities to defects noted in the distal esophageal epithelium in patients with gas-troesophageal reflux disease (GERD)

Defective Barrier Function in Neosquamous Epithelium

Radiofrequency ablation (RFA) of Barrett’s esophagus (BE) is a common strategy for the prevention of esophageal adenocarcinoma (EAC). After RFA, the ablated esophagus heals on acid suppressive therapy, and is re-populated with a stratified squamous epithelium, referred to as ‘neosquamous epithelium (NSE).’ Because the ability of the NSE to protect the underlying tissue from recurrent insult by reflux is unclear, we assessed the barrier function of NSE by comparing it to that of the native upper squamous epithelium (USE) in subjects having undergone RFA

Role of E-cadherin in the Pathogenesis of Gastroesophageal Reflux Disease

An early event in the pathogenesis of gastroesophageal reflux disease (GERD) is an acid-induced increase in junctional (paracellular) permeability in esophageal epithelium (EE). The molecular events that account for this change are unknown. E-cadherin is a junctional protein important in barrier function in EE. Therefore, defects in barrier function in EE were sought in GERD as well as whether their presence correlated with abnormalities in e-cadherin

Nrf2 deficiency impairs the barrier function of mouse oesophageal epithelium

As a major cellular defense mechanism, the Nrf2/Keap1 pathway regulates expression of genes involved in detoxification and stress response. Our previous study revealed activation of the Nrf2/Keap1 pathway at the maturation phase during mouse esophageal development, suggesting a potential function in epithelial defense. Here we hypothesize that Nrf2 is involved in the barrier function of esophageal epithelium, and plays a protective role against gastroesophageal reflux disease (GERD)

Enterococcus faecalis Gelatinase Mediates Intestinal Permeability via Protease-Activated Receptor 2

Microbial protease-mediated disruption of the intestinal epithelium is a potential mechanism whereby a dysbiotic enteric microbiota can lead to disease. This mechanism was investigated using the colitogenic, protease-secreting enteric microbe Enterococcus faecalis . Caco-2 and T-84 epithelial cell monolayers and the mouse colonic epithelium were exposed to concentrated conditioned media (CCM) from E. faecalis V583 and E. faecalis lacking the gelatinase gene ( gelE ). The flux of fluorescein isothiocyanate (FITC)-labeled dextran across monolayers or the mouse epithelium following exposure to CCM from parental or mutant E. faecalis strains indicated paracellular permeability. A protease-activated receptor 2 (PAR2) antagonist and PAR2-deficient (PAR2 −/− ) mice were used to investigate the role of this receptor in E. faecalis -induced permeability. Gelatinase (GelE) purified from E. faecalis V583 was used to confirm the ability of this protease to induce epithelial cell permeability and activate PAR2. The protease-mediated permeability of colonic epithelia from wild-type (WT) and PAR2 −/− mice by fecal supernatants from ulcerative colitis patients was assessed. Secreted E. faecalis proteins induced permeability in epithelial cell monolayers, which was reduced in the absence of gelE or by blocking PAR2 activity. Secreted E. faecalis proteins induced permeability in the colonic epithelia of WT mice that was absent in tissues from PAR2 −/− mice. Purified GelE confirmed the ability of this protease to induce epithelial cell permeability via PAR2 activation. Fecal supernatants from ulcerative colitis patients induced permeability in the colonic epithelia of WT mice that was reduced in tissues from PAR2 −/− mice. Our investigations demonstrate that GelE from E. faecalis can regulate enteric epithelial permeability via PAR2

Gut microbial communities from patients with anorexia nervosa do not influence body weight in recipient germ-free mice

Anorexia nervosa (AN) is a psychiatric disorder that presents with profound weight dysregulation, metabolic disturbances, and an abnormal composition of gut microbial communities. As the intestinal microbiota can influence host metabolism, the impact of enteric microbial communities from patients with AN on host weight and adiposity was investigated. Germ-free (GF) mice were colonized with fecal microbiotas from either patients with AN (n = 4) prior to inpatient treatment (AN T1, n = 50 recipient mice), the same 4 patients following clinical renourishment (AN T2, n = 53 recipient mice), or age- and sex-matched non-AN controls (n = 4 human donors; non-AN, n = 50 recipient mice). Biological and fecal microbiota data were analyzed with linear mixed-effects models. Body weight did not differ significantly between AN recipient mice (T1 and T2) and non-AN recipient mice following 4 weeks of colonization. Enteric microbiotas from recipient mice colonized with AN T1 and AN T2 fecal microbiotas were more similar to each other compared with enteric microbiotas from non-AN recipient mice. Specific bacterial families in the Actinobacteria, Bacteroidetes, and Firmicutes phyla were significantly associated with body weight, fat mass, and cecum weight irrespective of the donor group. These data suggest that body weight, fat mass, and cecum weight of colonized GF mice are associated with human fecal microbes and independent of donor AN status, although additional analyses with larger cohorts are warranted

Enterococcus faecalis Gelatinase Mediates Intestinal Permeability via Protease-Activated Receptor 2

Microbial protease-mediated disruption of the intestinal epithelium is a potential mechanism whereby a dysbiotic enteric microbiota can lead to disease. This mechanism was investigated using the colitogenic, protease-secreting enteric microbe Enterococcus faecalis. Caco-2 and T-84 epithelial cell monolayers and the mouse colonic epithelium were exposed to concentrated conditioned media (CCM) from E. faecalis V583 and E. faecalis lacking the gelatinase gene (gelE). The flux of fluorescein isothiocyanate (FITC)-labeled dextran across monolayers or the mouse epithelium following exposure to CCM from parental or mutant E. faecalis strains indicated paracellular permeability. A protease-activated receptor 2 (PAR2) antagonist and PAR2-deficient (PAR2(−/−)) mice were used to investigate the role of this receptor in E. faecalis-induced permeability. Gelatinase (GelE) purified from E. faecalis V583 was used to confirm the ability of this protease to induce epithelial cell permeability and activate PAR2. The protease-mediated permeability of colonic epithelia from wild-type (WT) and PAR2(−/−) mice by fecal supernatants from ulcerative colitis patients was assessed. Secreted E. faecalis proteins induced permeability in epithelial cell monolayers, which was reduced in the absence of gelE or by blocking PAR2 activity. Secreted E. faecalis proteins induced permeability in the colonic epithelia of WT mice that was absent in tissues from PAR2(−/−) mice. Purified GelE confirmed the ability of this protease to induce epithelial cell permeability via PAR2 activation. Fecal supernatants from ulcerative colitis patients induced permeability in the colonic epithelia of WT mice that was reduced in tissues from PAR2(−/−) mice. Our investigations demonstrate that GelE from E. faecalis can regulate enteric epithelial permeability via PAR2