Rab7-dependent regulation of goblet cell protein CLCA1 modulates gastrointestinal homeostasis.

Inflammation in ulcerative colitis is typically restricted to the mucosal layer of distal gut. Disrupted mucus barrier, coupled with microbial dysbiosis, has been reported to occur prior to the onset of inflammation. Here, we show the involvement of vesicular trafficking protein Rab7 in regulating the colonic mucus system. We identified a lowered Rab7 expression in goblet cells of colon during human and murine colitis. In vivo Rab7 knocked down mice (Rab7KD) displayed a compromised mucus layer, increased microbial permeability, and depleted gut microbiota with enhanced susceptibility to dextran sodium-sulfate induced colitis. These abnormalities emerged owing to altered mucus composition, as revealed by mucus proteomics, with increased expression of mucin protease chloride channel accessory 1 (CLCA1). Mechanistically, Rab7 maintained optimal CLCA1 levels by controlling its lysosomal degradation, a process that was dysregulated during colitis. Overall, our work establishes a role for Rab7-dependent control of CLCA1 secretion required for maintaining mucosal homeostasis.

Turning Lemons into Lemonade: Social Support as a Moderator of the Relationship Between Technostress and Quality of Life Among University Students.

Purpose: The overuse of internet-based technologies as a means of coping with the stress they generate has resulted in an alarming level of addiction, adversely impacting the quality of life and overall health of younger individuals. This social detachment, in turn, contributes to both physical and mental health deterioration. The potential remedy for this predicament lies in the application of social support as an antidote to internet addiction. In this context, our present study employs the Stress-Strain-Outcome model to explore the indirect effects of internet addiction and the moderating role of social support in relation to the influence of technostress on the quality of life of adults. Methods: We adopted a time-lagged design to collect data from university graduates and evaluated our study hypotheses using Mplus. Results: Our empirical findings highlight the significant influence of technostress on internet addiction, with the latter significantly mediating the relationship between technostress and quality of life. Furthermore, our results reveal that social support effectively moderates the indirect effects of technostress on quality of life through its impact on internet addiction. Conclusion: These findings can help researchers and educators better understand the underlying mechanisms between technostress and quality of life with social support as the silver lining. This form of social support holds the potential not only to alleviate internet addiction but also to positively enhance the quality of life and overall wellbeing of individuals facing these challenges. The implications of these findings and avenues for future research are also discussed.

The Quantification of Radiation Fibrosis Using Clinically Indicated Magnetic Resonance Imaging for Head and Neck Cancer Patients.

Currently, no objective method exists to measure the extent of fibrosis in swallowing musculature in head and neck cancer (HNC) patients. We developed and psychometrically tested a method of quantifying fibrosis volume using magnetic resonance imaging (MRI). The overall aim of this study was to determine if clinical MRI is a reliable tool to measure fibrosis of the pharyngeal musculature in patients with HNC managed with RT and to assess its potential to capture changes in fibrosis over time. Eligible participants were adults with HNC treated with radiation therapy (RT) who received minimally two MRIs and videofluoroscopic swallow (VFS) studies from baseline (pre-RT) up to 1-year post-RT. Two neuroradiologists independently contoured fibrosis volume in batches from MRIs using Vitrea™. Sufficient inter-rater reliability was set at Intraclass Correlation Coefficient (ICC) > 0.75. Two speech-language pathologists independently rated VFSs for swallowing impairment using standardized scales, with discrepancies resolved by consensus. MRI and VFS scores were correlated using Spearman's rank coefficient. Participants included 42 adults (male = 33); mean age 59 (SD = 8.8). ICC (95% Confidence Interval) for fibrosis volume was 0.34 (0, 0.76) for batch one and 0.43 (0, 0.82) for batch two. Consensus meetings were held after each batch. Sufficient reliability was reached by batch three (ICC = 0.95 (0.79, 0.99)). Fibrosis volume increased significantly from 3 to 12 months (mean change = 1.28 mL (SD = 5.21), p = 0.006), as did pharyngeal impairment from baseline to 12 months (mean score change = 3.05 (SD = 3.02), p = 0.003). Fibrosis volume moderately correlated with pharyngeal impairment at 3 and 12 months (0.49, p = 0.004 and 0.59, p = 0.005, respectively). We demonstrated a reliable measure of fibrosis volume in swallowing musculature from existing clinical MRIs and identified that larger fibrosis volume was associated with worse swallowing function. The reliable capture of fibrosis volume offers a pragmatic method for early detection of fibrosis and concomitant dysphagia.

DeSUMOylase SENP7-Mediated Epithelial Signaling Triggers Intestinal Inflammation via Expansion of Gamma-Delta T Cells.

Inflammatory bowel disease (IBD) is a complex autoimmune disorder recently shown to be associated with SUMOylation, a post-translational modification mechanism. Here, we have identified a link between epithelial deSUMOylases and inflammation in IBD. DeSUMOylase SENP7 was seen to be upregulated specifically in intestinal epithelial cells in both human IBD and a mouse model. In steady state, but not IBD, SENP7 expression was negatively regulated by a direct interaction and ubiquitination by SIAH2. Upregulated SENP7 in inflamed tissue displayed a distinct interactome. These changes led to an expansion of localized proinflammatory γδ T cells. Furthermore, in vivo knockdown of SENP7 or depletion of γδ T cells abrogated dextran sulfate sodium (DSS)-induced gut inflammation. Strong statistical correlations between upregulated SENP7 and high clinical disease indices were observed in IBD patients. Overall, our data reveal that epithelial SENP7 is necessary and sufficient for controlling gut inflammation, thus highlighting its importance as a potential drug target.

Initial presentation of lung cancer in the emergency department: a descriptive analysis.

BACKGROUND: Guidelines aimed at improving care for lung cancer, the leading cause of cancer-related death in Canada and worldwide, require accurate knowledge of the diagnostic setting or pathway. We sought to determine how often lung cancer is initially diagnosed through the emergency department. METHODS: We performed a descriptive study that included all cases of primary lung cancer diagnosed in residents of Nova Scotia in 2014. Cancer registry data included diagnostic data and date of death to Aug. 31, 2016. We reviewed linked hospital records, including laboratory and imaging results, to identify the first positive diagnostic study and the route of presentation (emergency department v. other). We evaluated time from diagnosis to death as a function of presentation route using Kaplan-Meier curves and Cox regression (hazard rate ratios [HRRs]). RESULTS: Sufficient data were available for 946 of 951 cases identified, of which 336 (35.5%) were diagnosed through the emergency department. Cases diagnosed via the emergency department were more likely to be at an advanced stage (stage IV, 59.5% v. 43.4%), with patients experiencing shorter survival (1-yr survival, 28.4% v. 49.5%), including stage-specific survival. Mortality for cases diagnosed in the emergency department was 54% higher than for the non-emergency department group after adjusting for age and stage (HRR 1.54, 95% confidence interval 1.32-1.81). Few patients (7.1%, n = 24) who presented to the emergency department reported having no family physician. INTERPRETATION: The emergency department is a common route of presentation for lung cancer and is associated with advanced stage at diagnosis and reduced survival time. Strategies are needed to encourage pre-emergent diagnosis and to ensure that emergency providers are supported in the initial care of patients with lung cancer.

SUMOylation pathway alteration coupled with downregulation of SUMO E2 enzyme at mucosal epithelium modulates inflammation in inflammatory bowel disease.

Post-translational modification pathways such as SUMOylation are integral to all cellular processes and tissue homeostasis. We investigated the possible involvement of SUMOylation in the epithelial signalling in Crohn's disease (CD) and ulcerative colitis (UC), the two major forms of inflammatory bowel disease (IBD). Initially in a murine model of IBD, induced by dextran-sulfate-sodium (DSS mice), we observed inflammation accompanied by a lowering of global SUMOylation of colonic epithelium. The observed SUMOylation alteration was due to a decrease in the sole SUMO E2 enzyme (Ubc9). Mass-spectrometric analysis revealed the existence of a distinct SUMOylome (SUMO-conjugated proteome) in DSS mice with alteration of key cellular regulators, including master kinase Akt1. Knocking-down of Ubc9 in epithelial cells resulted in dramatic activation of inflammatory gene expression, a phenomenon that acted via reduction in Akt1 and its SUMOylated form. Importantly, a strong decrease in Ubc9 and Akt1 was also seen in endoscopic biopsy samples (N = 66) of human CD and UC patients. Furthermore, patients with maximum disease indices were always accompanied by severely lowered Ubc9 or SUMOylated-Akt1. Mucosal tissues with severely compromised Ubc9 function displayed higher levels of pro-inflammatory cytokines and compromised wound-healing markers. Thus, our results reveal an important and previously undescribed role for the SUMOylation pathway involving Ubc9 and Akt1 in modulation of epithelial inflammatory signalling in IBD.

Adiponectin-induced ERK and Akt phosphorylation protects against pancreatic beta cell apoptosis and increases insulin gene expression and secretion.

The functional impact of adiponectin on pancreatic beta cells is so far poorly understood. Although adiponectin receptors (AdipoR1/2) were identified, their involvement in adiponectin-induced signaling and other molecules involved is not clearly defined. Therefore, we investigated the role of adiponectin in beta cells and the signaling mediators involved. MIN6 beta cells and mouse islets were stimulated with globular (2.5 µg/ml) or full-length (5 µg/ml) adiponectin under serum starvation, and cell viability, proliferation, apoptosis, insulin gene expression, and secretion were measured. Lysates were subjected to Western blot analysis to determine phosphorylation of AMP-activated protein kinase (AMPK), Akt, or ERK. Functional significance of signaling was confirmed using dominant negative mutants or pharmacological inhibitors. Participation of AdipoRs was assessed by overexpression or siRNA. Adiponectin failed to activate AMPK after 10 min or 1- and 24-h stimulation. ERK was significantly phosphorylated after 24-h treatment with adiponectin, whereas Akt was activated at all time points examined. 24-h stimulation with adiponectin significantly increased cell viability by decreasing cellular apoptosis, and this was prevented by dominant negative Akt, wortmannin (PI3K inhibitor), and U0126 (MEK inhibitor). Moreover, adiponectin regulated insulin gene expression and glucose-stimulated insulin secretion, which was also prevented by wortmannin and U0126 treatment. Interestingly, the data also suggest adiponectin-induced changes in Akt and ERK phosphorylation and caspase-3 may occur independent of the level of AdipoR expression. This study demonstrates a lack of AMPK involvement and implicates Akt and ERK in adiponectin signaling, leading to protection against apoptosis and stimulation of insulin gene expression and secretion in pancreatic beta cells.