Epithelial Mucus Production Research Articles

A269 SEX-DEPENDENT EFFECT OF PANCREASTATIN INHIBITION ON COLON MUCOSAL INTEGRITY IN HOMEOSTATIC CONDITION

Abstract Background Sex bias in inflammatory bowel disease (IBD)-associated colorectal cancer (CRC) epidemiology is well known. Pancreastatin (PST), an epithelial cells-derived peptide overexpressed in IBD patients, regulates the endoplasmic reticulum (ER) and survival signalling involved in CRC. Pancreastatin inhibitor 8 (PSTi8), an inhibitor of PST, showed promising anti-inflammatory effects in IBD male mice model. However, no data exists regarding PST’s role in colon mucosal regeneration and epithelium maintenance. Aims Here, we investigated the impact of PSTi8 treatment on colonic epithelial cells in male and female mice under homeostatic conditions. Methods Male and female C57BL/6 mice were treated with PSTi8 (2.5mg/mL/kg, i.r.) or PBS for six days. Epithelial cells’ proliferation (Ki67) and differentiation (cytokeratin-20) were measured by immunofluorescence. Genetic markers for differentiated epithelial cells (goblet Muc2 and Tuft Dclk1), stem cells (fast-cycling Lgr5, reserve Hopx and fetal-like Ly6a), stem cell regulator (BMP4), epithelial cells lineage commitment (Atoh1, Hes1, Gfl1), ER activation (ATF6), and apoptosis (CHOP) were tested by qRT-PCR. Results PSTi8 treatment decreased epithelial cell proliferation in both sexes. The inhibition of PST lowered the differentiation of epithelial cells and mucus production and increased tuft cell gene expression in females but not in male mice. In females, PSTi8 treatment increased fast-cycling stem cells but lower reserve and fetal-like stem cells in both sexes. In addition, PST inhibition significantly downregulated BMP4, which regulates epithelial cell differentiation, in females while not altering its expression in males. In contrast, PSTi8 treatment significantly increased transcription factors regulating epithelial cells' self-renewal and lineage commitments Hes1 and GFI1 in females but decreased Atoh1 in both sexes. PST inhibition enhanced gene expression of ER stress molecules ATF6 and CHOP in female and ATF6 in male mice. CHOP remained unaltered by PST inhibition in males. Conclusions PSTi8 alters colonic epithelial regeneration, differentiation, and thus maintenance in a sex-dependent manner. Funding Agencies CIHRChildren’s Hospital Research Institute of Manitoba (CHRIM)/Research Manitoba

Modulation of gut microbiota and intestinal immune response in gilthead seabream (Sparus aurata) by dietary bile salt supplementation.

Given their role in lipid digestion, feed supplementation with bile salts could be an economic and sustainable solution to alterations in adiposity and intestinal inflammation generated by some strategies currently used in aquaculture. An important part of the metabolism of bile salts takes place in the intestine, where the microbiota transforms them into more toxic forms. Consequently, we aimed to evaluate the gut immune response and microbial populations in gilthead seabream (Sparus aurata) fed a diet supplemented with a blend of bile salts with proven background as a regulator of lipid metabolism and fat content. After the 90-day feeding trial, a differential modulation of the microbiota between the anterior and posterior intestine was observed. While in the anterior intestine the relative abundance of Desulfobacterota doubled, in the posterior intestine, the levels of Firmicutes increased and Proteobacteria, Actinobacteriota, and Campylobacterota were reduced when supplementing the diet with bile salts. Even so, only in the anterior intestine, there was a decrease in estimated richness (Chao1 and ACE indices) in presence of dietary bile salts. No significant differences were displayed in alpha (Shannon and Simpson indices) nor beta-diversity, showing that bile sales did not have a great impact on the intestinal microbiota. Regarding the gene expression profile in 2 h postprandial-fish, several changes were observed in the analyzed biomarkers of epithelial integrity, nutrient transport, mucus production, interleukins, cell markers, immunoglobulin production and pathogen recognition receptors. These results may indicate the development of an intestinal immune-protective status to tackle future threats. This work also suggests that this immune response is not only regulated by the presence of the dietary bile salts in the intestine, but also by the microbial populations that are in turn modulated by bile salts. After a fasting period of 2 days, the overall gene expression profile was stabilized with respect to fish fed the unsupplemented diet, indicating that the effect of bile salts was transient after short periods of fasting. On the balance, bile salts can be used as a dietary supplement to enhance S. aurata farming and production without compromising their intestinal health.

Maltodextrin Consumption Impairs the Intestinal Mucus Barrier and Accelerates Colitis Through Direct Actions on the Epithelium.

Food additives are common components of processed foods consumed in a Western diet. In inflammatory bowel disease patients, some diets that exclude food additives improved clinical disease parameters, suggesting a link between food additives and disease pathogenesis. Food additives also enhanced disease severity in mouse colitis models through incompletely described mechanisms. This study examined the mechanisms by which the food additive maltodextrin (MDX) alters the development of colitis in a murine model. Interleukin-10 knockout (IL10KO) mice were fed diets supplemented with MDX or carboxymethyl cellulose (CMC) to determine their impact on colitis onset and severity; microbiome composition, function, and location; colonic immune cell infiltrates; and mucus layer integrity. Primary IL10KO colonic epithelial monolayers were used to dissect the impact of MDX directly on epithelial differentiation and mucus production. MDX or CMC consumption increased the incidence and severity of colitis, as well as decreased microbiome diversity, altered microbial composition, and decreased fecal acetic acid levels. The number of mucus producing cells were decreased in food additive fed mice and resulted in increased microbial proximity to the intestinal epithelium. Additionally, MDX supplementation resulted in crypt hyperplasia and expansion of the HopX+ injury renewal stem cell niche. In primary intestinal epithelial-derived monolayers devoid of microbes and immune cells, MDX exposure decreased goblet cell number and mucus production in association with downregulated expression of the transcription factor Klf4, a marker of terminally differentiated goblet cells. These results suggest MDX disrupts the balance of epithelial cell differentiation and proliferation to contribute to disease pathogenesis through direct and indirect actions on the intestinal epithelial barrier.

Cross-talk of inflammatory mediators and airway epithelium reveals the cystic fibrosis transmembrane conductance regulator as a major target.

Airway inflammation, mucus hyperproduction and epithelial remodelling are hallmarks of many chronic airway diseases, including asthma, COPD and cystic fibrosis. While several cytokines are dysregulated in these diseases, most studies focus on the response of airways to interleukin (IL)-4 and IL-13, which have been shown to induce mucus hyperproduction and shift the airway epithelium towards a hypersecretory phenotype.We hypothesised that other cytokines might induce the expression of chloride (Cl−) channels/transporters, and regulate epithelial differentiation and mucus production. To this end, fully differentiated human airway basal cells (BCi-NS1.1) were treated with cytokines identified as dysregulated in those diseases, namely IL-8, IL-1β, IL-4, IL-17A, IL-10 and IL-22, and tumour necrosis factor-α.Our results show that the cystic fibrosis transmembrane conductance regulator (CFTR) is the main Cl− channel modulated by inflammation, in contrast to transmembrane protein 16A (TMEM16A), whose levels only changed with IL-4. Furthermore, we identified novel roles for IL-10 and IL-22 by influencing epithelial differentiation towards ciliated cells and away from pulmonary ionocytes. In contrast, IL-1β and IL-4 reduced the number of ciliated cells while increasing club cells. Interestingly, while IL-1β, IL-4 and IL-10 upregulated CFTR expression, IL-4 was the only cytokine that increased both its function and the number of CFTR-expressing club cells, suggesting that this cell type may be the main contributor for CFTR function. Additionally, all cytokines assessed increased mucus production through a differential upregulation of MUC5AC and MUC5B transcript levels.This study reveals a novel insight into differentiation resulting from the cross-talk of inflammatory mediators and airway epithelial cells, which is particularly relevant for chronic airway diseases.

Cystic Fibrosis Clinical Isolates of Aspergillus fumigatus Induce Similar Muco-inflammatory Responses in Primary Airway Epithelial Cells.

Aspergillus is increasingly associated with lung inflammation and mucus plugging in early cystic fibrosis (CF) disease during which conidia burden is low and strains appear to be highly diverse. It is unknown whether clinical Aspergillus strains vary in their capacity to induce epithelial inflammation and mucus production. We tested the hypothesis that individual colonising strains of Aspergillus fumigatus would induce different responses. Ten paediatric CF Aspergillus isolates were compared along with two systemically invasive clinical isolates and an ATCC reference strain. Isolates were first characterised by ITS gene sequencing and screened for antifungal susceptibility. Three clusters (A−C) of Aspergillus isolates were identified by ITS. Antifungal susceptibility was variable, particularly for itraconazole. Submerged CF and non-CF monolayers as well as differentiated primary airway epithelial cell cultures were incubated with conidia for 24 h to allow germination. None of the clinical isolates were found to significantly differ from one another in either IL-6 or IL-8 release or gene expression of secretory mucins. Clinical Aspergillus isolates appear to be largely homogenous in their mucostimulatory and immunostimulatory capacities and, therefore, only the antifungal resistance characteristics are likely to be clinically important.

Harnessing Colon Chip Technology to Identify Commensal Bacteria That Promote Host Tolerance to Infection.

Commensal bacteria within the gut microbiome contribute to development of host tolerance to infection, however, identifying specific microbes responsible for this response is difficult. Here we describe methods for developing microfluidic organ-on-a-chip models of small and large intestine lined with epithelial cells isolated from duodenal, jejunal, ileal, or colon organoids derived from wild type or transgenic mice. To focus on host-microbiome interactions, we carried out studies with the mouse Colon Chip and demonstrated that it can support co-culture with living gut microbiome and enable assessment of effects on epithelial adhesion, tight junctions, barrier function, mucus production, and cytokine release. Moreover, infection of the Colon Chips with the pathogenic bacterium, Salmonella typhimurium, resulted in epithelial detachment, decreased tight junction staining, and increased release of chemokines (CXCL1, CXCL2, and CCL20) that closely mimicked changes previously seen in mice. Symbiosis between microbiome bacteria and the intestinal epithelium was also recapitulated by populating Colon Chips with complex living mouse or human microbiome. By taking advantage of differences in the composition between complex microbiome samples cultured on each chip using 16s sequencing, we were able to identify Enterococcus faecium as a positive contributor to host tolerance, confirming past findings obtained in mouse experiments. Thus, mouse Intestine Chips may represent new experimental in vitro platforms for identifying particular bacterial strains that modulate host response to pathogens, as well as for investigating the cellular and molecular basis of host-microbe interactions.

A229 PROMOTION OF COLONIC ANASTOMOTIC HEALING WITH PERIOPERATIVE SUPPLEMENTATION WITH OLIGOSACCHARIDES

Abstract Background Colorectal resection is a standard procedure in the management of colorectal cancer (CRC) and inflammatory bowel disease. Anastomotic leak (AL) is a major complication in colorectal resections, and the gut microbiota may play a role in the healing and development of AL. Short-chain fatty acids (SCFAs), namely butyrate, have been involved in anastomotic healing when administered into the bowel via enema. Due to the mechanical stress associated with enemas after the confection of a fresh and fragile anastomosis, other butyrate-increasing strategies are required. Aims To promote anastomotic healing and prevent AL by using inulin and galacto-oligosaccharides (GOS) supplementation to modulate the microbiota toward a butyrate-producing profile. Methods Mice were fed diets supplemented with inulin, GOS or cellulose, as a non-fermentable control, for two weeks and underwent a proximal colonic anastomosis under general anesthesia. Healing of the anastomosis, both macroscopically and microscopically, was assessed six days after surgery. Epithelial proliferation, mucus production and integrity of the gut barrier were assessed. Results Inulin and GOS supplementation increased SCFAs in the colon and were associated with better postoperative weight recovery and macroscopic anastomotic healing. Microscopically, mucosal continuity was promoted by inulin and GOS. Mucus production was found to be similar in all groups. The gut barrier was found to be improved with inulin and GOS as shown by less bacterial translocation. Conclusions Inulin and GOS may prevent AL and promote anastomotic healing. This effect appears to be mediated by improved mucosal proliferation. Funding Agencies CIHRNatural Sciences and Engineering Research Council of Canada; Institut du cancer de Montréal; Fonds de recherche du Québec en santé

Mechanisms and regulation of IL-22-mediated intestinal epithelial homeostasis and repair

AimsUlcerative colitis and Crohn's disease, collectively known as inflammatory bowel disease (IBD), are chronic inflammatory disorders of the intestine for which key elements in disease initiation and perpetuation are defects in epithelial barrier integrity. Achieving mucosal healing is essential to ameliorate disease outcome and so new therapies leading to epithelial homeostasis and repair are under investigation. This study was designed to determine the mechanisms by which IL-22 regulates intestinal epithelial cell function. Main methodsHuman intestinal organoids and resections, as well as mice were used to evaluate the effect of IL-22 on stem cell expansion, proliferation and expression of mucus components. IL-22 effect on barrier function was assessed in polarized T-84 cell monolayers. Butyrate co-treatments and organoid co-cultures with immune cells were performed to monitor the impact of microbial-derived metabolites and inflammatory environments on IL-22 responses. Key findingsIL-22 led to epithelial stem cell expansion, proliferation, barrier dysfunction and anti-microbial peptide production in human and mouse models evaluated. IL-22 also altered the mucus layer by inducing an increase in membrane mucus but a decrease in secreted mucus and goblet cell content. IL-22 had the same effect on anti-microbial peptides and membrane mucus in both healthy and IBD human samples. In contrast, this IL-22-associated epithelial phenotype was different when treatments were performed in presence of butyrate and organoids co-cultured with immune cells. SignificanceOur data indicate that IL-22 promotes epithelial regeneration, innate defense and membrane mucus production, strongly supporting the potential clinical utility of IL-22 as a mucosal healing therapy in IBD.

Short-term whole body cigarette smoke exposure induces regional differences in cellular response in the mouse larynx.

The larynx is an essential organ in the respiratory tract and necessary for airway protection, respiration, and phonation. Cigarette smoking is a significant risk factor associated with benign and malignant laryngeal diseases. Despite this association, the underlying mechanisms by which cigarette smoke (CS) drives disease development are not well elucidated. In the current study, we developed a short-term murine whole body inhalation model to evaluate the first CS-induced cellular responses in the glottic [i.e. vocal fold (VF)] and subglottic regions of the larynx. Specifically, we investigated epithelial cell proliferation, cell death, surface topography, and mucus production, at various time points (1 day, 5 days, 10 days) after ∼ 2 h exposure to 3R4F cigarettes (Delivered dose: 5.6968 mg/kg per cigarette) and following cessation for 5 days after a 5 day CS exposure (CSE). CSE elevated levels of BrdU labeled proliferative cells and p63 labeled epithelial basal cells on day 1 in the VF. CSE increased proliferative cells in the subglottis at days 5, 10 and following cessation in the subglottis. Cleaved caspase-3 apoptotic activity was absent in VF at all time points and increased at day 1 in the subglottis. Evaluation of the VF surface by scanning electron microscopy (SEM) revealed significant epithelial microprojection damage at day 10 and early signs of necrosis at days 5 and 10 post-CSE. SEM visualizations additionally indicated the presence of deformed cilia at days 5 and 10 after CSE and post-cessation in the respiratory epithelium lined subglottis. In terms of mucin content, the impact of short-term CSE was observed only at day 10, with decreasing acidic mucin levels and increasing neutral mucin levels. Overall, these findings reveal regional differences in murine laryngeal cellular responses following short-term CSE and provide insight into potential mechanisms underlying CS-induced laryngeal disease development.

A Descriptive Review of Epidemiology of COVID-19 in Smokers

Background: COVID-19 is an ongoing global pandemic with paucity of the understanding of the natural history of the disease and how it affects smokers. We aim to study the outcomes of COVID-19 in smokers in this descriptive review. Coronavirus disease 2019 caused by severe acute respiratory syndrome Coronavirus 2, gains entry to bronchial epithelial cells by attachment of the viral spike protein to Angiotensin-Converting Enzyme-2 (ACE-2) receptors. Accordingly, this review aims to understand the associated risk and worsen disease in relation to smoking and explore conflicting information regarding nicotine as well as its potential protective role. Methods: We conducted a non-systematic review of databases with search engines such as, PubMed, Google Scholar with keywords like “COVID-19,” “SARS-CoV-2,” “novel coronavirus,” smoking,” “smokers,” “nicotine.” It included English articles related to the epidemiology of COVID-19 in adult smokers, containing systematic reviews, meta-analysis, prospective and retrospective cohort studies, cross-sectional studies, case series, and case reports based on the relevance of titles and abstracts to the topic. Results: A total of 33 articles were reviewed. Smokers were 1.4 times more likely to have severe COVID-19 (RR = 1.4, 95% CI: 0.98 - 2.00), and 2.4 times more likely to require an ICU admission (RR = 2.4, CI: 1.43 - 4.04) when compared to non-smokers (n = 926). Current smokers were less likely to experience an adverse outcome (OR: 0.42, 95% CI: 0.24 - 0.74), compared to former smokers. 22% of current smokers and 46% of former smokers had more severe complications compared to non-smokers with COVID-19 infection. Current smokers had a case fatality rate of 38.5% (n = 1790). They had higher odds of mortality compared to non-smokers (OR = 1.25), especially males > 65 years age (OR = 2.51). Tobacco smoke upregulates inflammatory cytokines like TNF-α, IL-1β, and neutrophils by activating NF-k. Hence, it leads to increased epithelial cell permeability, mucus production, and impaired mucociliary clearance. The pro-inflammatory action of tobacco smoke impairs the basal laminar cells and causes endothelial dysfunction of the BBB and blood vessels, which leads to neurological, cerebrovascular, and thrombotic complications. Conclusion: Smoking is associated with worse outcomes and mortality in COVID-19. Public education about smoking cessation should be implemented along with standard guidelines to prevent disease progression in this susceptible population.

An unusual case of infected uterus masculinus in a dog

BackgroundParaprostatic cysts are large structures that develop between the prostate gland and urinary bladder, usually in older, intact dogs. Their incidence is reported to be 1.1–5.3% in dogs with prostatic disease. The aetiology of paraprostatic cysts is not fully understood, but they are believed to develop from the uterus masculinus. Whereas the uterus masculinus has been reported to communicate with the urethra in men and horses, no communication between the uterus masculinus and urethra has been identified in dogs.Case presentationAn entire male dog was presented with a bloody discharge from its penis and tenesmus of 5 days’ duration. A diagnosis of cystic uterus masculinus was made on the basis of the findings of abdominal ultrasonography and histopathology of tissues obtained during an exploratory laparotomy. In addition, a Sertoli cell tumour affecting both testes was diagnosed following scrotal castration. The cystic uterus masculinus was completely resected, after which the tenesmus and bloody discharge resolved. Thus, cystic uterus masculinus should be considered as a differential diagnosis for a paraprostatic cyst when such a lesion develops as part of the feminising effect of a Sertoli cell tumour.ConclusionsCystic uterus masculinus should be considered as a differential diagnosis for tenesmus and penile discharge, and for structures resembling paraprostatic cysts. This case report confirms that a uterus masculinus can communicate with the urethra in dogs, as in other species, and demonstrates endocrine responsiveness, manifesting as epithelial and glandular metaplasia and mucus production, with the potential for subsequent infection.

Intestine-on-chip device increases ECM remodeling inducing faster epithelial cell differentiation.

An intestine-on-chip has been developed to study intestinal physiology and pathophysiology as well as intestinal transport absorption and toxicity studies in a controlled and human similar environment. Here, we report that dynamic culture of an intestine-on-chip enhances extracellular matrix (ECM) remodeling of the stroma, basement membrane production and speeds up epithelial differentiation. We developed a three-dimensional human intestinal stromal equivalent composed of human intestinal subepithelial myofibroblasts embedded in their own ECM. Then, we cultured human colon carcinoma-derived cells in both static and dynamic conditions in the opportunely designed microfluidic system until the formation of a well-oriented epithelium. This low cost and handy microfluidic device allows to qualitatively and quantitatively detectepithelial polarization andmucus production as well as monitorbarrier function and ECM remodeling after nutraceutical treatment.

Intestinal epithelial deletion of the glucocorticoid receptor NR3C1 alters expression of inflammatory mediators and barrier function.

Glucocorticoids (GCs) are important hormones involved in the regulation of multiple physiologic functions. GCs are also widely used in anti-inflammatory/immunosuppressant drugs. GCs are synthesized by the adrenal cortex as part of the hypothalamus-pituitary-adrenal axis and also by intestinal epithelial cells, among other peripheral sites. GCs are one of the main therapy choices for the exacerbations of inflammatory bowel disease, but they are not useful to prolong remission, and development of tolerance with secondary treatment failure is frequent. Thus, GC actions at the intestinal epithelial level are of great importance, both physiologically and pharmacologically. We generated a tamoxifen-inducible nuclear receptor subfamily 3 group C member 1 (NR3C1)ΔIEC mouse model to study the effects of GCs on epithelial cells in vivo. Nr3c1 deletion in epithelial cells of the small intestine and colon was associated with limited colonic inflammation at 1 wk postdeletion, involving augmented epithelial proliferation and mucus production, plus local and systemic immune/inflammatory changes. This phenotype regressed substantially, but not completely, after 2 wk. The mechanism may involve augmented inflammatory signaling by epithelial cells or defective barrier function. We conclude that the epithelial GC receptor plays a significant role in colonic homeostasis in basal conditions, but its deficiency can be compensated in the short term. Future studies are required to assess the impact of Nr3c1 deletion in other conditions such as experimental colitis.-Aranda, C. J., Arredondo-Amador, M., Ocón, B., Lavín, J. L., Aransay, A. M., Martínez-Augustin, O., Sánchez de Medina, F. Intestinal epithelial deletion of the glucocorticoid receptor NR3C1 alters expression of inflammatory mediators and barrier function.

Inhibition of MAPK and STAT3-SOCS3 by Sakuranetin Attenuated Chronic Allergic Airway Inflammation in Mice.

Asthma allergic disease is caused by airway chronic inflammation. Some intracellular signaling pathways, such as MAPK and STAT3-SOCS3, are involved in the control of airway inflammation in asthma. The flavonoid sakuranetin demonstrated an anti-inflammatory effect in different asthma models. Our aim was to clarify how sakuranetin treatment affects MAPK and STAT3-SOCS3 pathways in a murine experimental asthma model. Mice were submitted to an asthma ovalbumin-induction protocol and were treated with vehicle, sakuranetin, or dexamethasone. We assayed the inflammatory profile, mucus production, and serum antibody, STAT3-SOCS3, and MAPK levels in the lungs. Morphological alterations were also evaluated in the liver. LPS-stimulated RAW 264.7 cells were used to evaluate the effects of sakuranetin on nitric oxide (NO) and cytokine production. In vivo, sakuranetin treatment reduced serum IgE levels, lung inflammation (eosinophils, neutrophils, and Th2/Th17 cytokines), and respiratory epithelial mucus production in ovalbumin-sensitized animals. Considering possible mechanisms, sakuranetin inhibits the activation of ERK1/2, JNK, p38, and STAT3 in the lungs. No alterations were found in the liver for treated animals. Sakuranetin did not modify in vitro cell viability in RAW 264.7 and reduced NO release and gene expression of IL-1β and IL-6 induced by LPS in these cells. In conclusion, our data showed that the inhibitory effects of sakuranetin on eosinophilic lung inflammation can be due to the inhibition of Th2 and Th17 cytokines and the inhibition of MAPK and STAT3 pathways, reinforcing the idea that sakuranetin can be considered a relevant candidate for the treatment of inflammatory allergic airway disease.

NLRP6 Deficiency in CD4 T Cells Decreases T Cell Survival Associated with Increased Cell Death.

The nucleotide-binding oligomerization domain (NOD)-like receptors belong to the family of pattern recognition receptors (PRRs). NOD-like receptors play a role in regulation of innate immune response by recognition of both pathogen-associated molecular patterns that are engulfed during phagocytic process and danger-associated molecular patterns that are mainly byproducts of cell stress mediated response. NOD-like family pyrin domain containing 6 (NLRP6) is one of the 14 pyrin domain-containing receptors. NLRP6 is highly expressed by epithelial and goblet cells to regulate epithelial renewal and mucus production in mice and humans, but its function in T cells is rather unknown. Increased caspase-1 activation and cell death were observed in mouse Nlrp6-deficient T cells following adoptive transfer into Rag2-deficient mice, indicating that Nlrp6 deficiency in CD4+ T cells led to decreased survival.

Abstract TMP118: The Gut Microbiota Can Protect Against the Onset of Symptoms in an Animal Model of Cerebral Small Vessel Disease

It has become increasingly evident that disruption of the gut microbiota plays an important role in multiple host disease states. We hypothesize that maintaining a healthy gut microbiome protects against the development of cerebral small vessel disease (CSVD), an inflammatory disease accompanied by blood-brain barrier (BBB) breakdown and neuroinflammation. To test our hypothesis, we altered the gut microbiota of spontaneously hypertensive stroke-prone rats (SHRSPs), a model of CSVD associated with hypertension, to resemble that of healthy/asymptomatic WKY control rats. At birth SHRSP pups were removed from their birth moms and nursed by either WKY (SW rats) or SHRSP (SS) foster dams until 21 days of age. At 20 weeks, markers associated with neuroinflammation were significantly decreased in SW rats compared to SS rats (NF-κB1 by 68%, TLR-2 by 58%, and TLR-4 by 54%, P≤ 0.01, n=5-6/ group). When compared to SS rats, SW rats showed a 33% (P=0.045) decrease in IgG extravasation into brain indicating greater BBB integrity. Systolic blood pressure at 20 weeks in SW was 173±6 mm Hg compared to 201±6 mm Hg in SS rats (P=0.003) and these pressures remained stable for until at least 30 weeks. Analysis of microbiota in feces revealed that gut microbiota of SW rats were significantly different from SS rats (P<0.05, principal components analysis of weighted Unifrac distances, n=5-6), resembled the microbiome in WKY rats, and showed > 2-fold increase in the abundance of the genus, Akkermansia, in SW compared to SS rats (6.1% vs 3.0%, P=0.01). Akkermansia can enhance gut integrity by stimulating epithelial cell mucus production and enhancing tight junctions. We conclude that the gut microbiota can influence the onset of CSVD-like symptoms even in the genetic SHRSP model. Maintaining a microbiota similar to WKY control rats, which includes an increased abundance of Akkermansia, appears to protect against the onset of CSVD. Altering the gut microbiota in humans could be an effective prophylactic measure to protect against CSVD.

Butyrate Attenuates Lung Inflammation by Negatively Modulating Th9 Cells

Th9 cells orchestrate allergic lung inflammation by promoting recruitment and activation of eosinophils and mast cells, and by stimulating epithelial mucus production, which is known to be mainly dependent on IL-9. These cells share developmental pathways with induced regulatory T cells that may determine the generation of one over the other subset. In fact, the FOXP3 transcription factor has been shown to bind il9 locus and repress IL-9 production. The microbiota-derived short-chain fatty acids (SCFAs) butyrate and propionate have been described as FOXP3 inducers and are known to have anti-inflammatory properties. While SCFAs attenuate lung inflammation by inducing regulatory T cells and suppressing Th2 responses, their effects on Th9 cells have not been addressed yet. Therefore, we hypothesized that SCFAs would have a protective role in lung inflammation by negatively modulating differentiation and function of Th9 cells. Our results demonstrated that butyrate is more effective than propionate in promoting FOXP3 expression and IL-9 repression. In addition, propionate was found to negatively impact in vitro differentiation of IL-13-expressing T cells. Butyrate treatment attenuated lung inflammation and mucus production in OVA-challenged mice, which presented lower frequency of lung-infiltrated Th9 cells and eosinophils. Both Th9 cell adoptive transfer and IL-9 treatment restored lung inflammation in butyrate-treated OVA-challenged mice, indicating that the anti-inflammatory effects of butyrate may rely on suppressing Th9-mediated immune responses.

The airway epithelium in asthma.

Asthma is a genetically and phenotypically complex disease that has a major impact on global health. Signs and symptoms of asthma are caused by the obstruction of airflow through the airways. The epithelium that lines the airways plays a major role in maintaining airway patency and in host defense. The epithelium initiates responses to inhaled or aspirated substances, including allergens, viruses, and bacteria, and epithelial-derived cytokines are important in the recruitment and activation of immune cells in the airway. Changes in the structure and function of the airway epithelium are a prominent feature of asthma. Approximately half of individuals with asthma have evidence of active type 2 immune responses in the airway. In these individuals, epithelial cytokines promote type 2 responses, and responses to type 2 cytokines result in increased epithelial mucus production and other effects that cause airway obstruction. Recent work also implicates other epithelial responses, including interleukin-17, interferon and ER stress responses, that may contribute to asthma pathogenesis and provide new targets for therapy.

Vesicular acetylcholine transport deficiency potentiates some inflammatory responses induced by diesel exhaust particles

Endogenous acetylcholine (ACh), which depends of the levels of vesicular ACh transport (VAChT) to be released, is the central mediator of the cholinergic anti-inflammatory system. ACh controls the release of cytokine in different models of inflammation. Diesel exhaust particles (DEP) are one of the major environmental pollutants produced in large quantity by automotive engines in urban center. DEP bind the lung parenchyma and induce inflammation. We evaluated whether cholinergic dysfunction worsens DEP-induced lung inflammation. Male mice with decreased ACh release due to reduced expression of VAChT (VAChT-KD mice) were submitted to DEP exposure for 30 days (3 mg/mL of DEP, once a day, five days a week) or saline. Pulmonary function and inflammation as well as extracellular matrix fiber deposition were evaluated. Additionally, airway and nasal epithelial mucus production were quantified. We found that DEP instillation worsened lung function and increased lung inflammation. Higher levels of mononuclear cells were observed in the peripheral blood of both wild-type (WT) and VAChT-KD mice. Also, both wild-type (WT) and VAChT-KD mice showed an increase in macrophages in bronchoalveolar lavage fluid (BALF) as well as increased expression of IL-4, IL-6, IL-13, TNF-α, and NF-κB in lung cells. The collagen fiber content in alveolar septa was also increased in both genotypes. On the other hand, we observed that granulocytes were increased only in VAChT-KD peripheral blood. Likewise, increased BALF lymphocytes and neutrophils as well as increased elastic fibers in alveolar septa, airway neutral mucus, and nasal epithelia acid mucus were observed only in VAChT-KD mice. The cytokines IL-4 and TNF-α were also higher in VAChT-KD mice compared with WT mice. In conclusion, decreased ability to release ACh exacerbates some of the lung alterations induced by DEP in mice, suggesting that VAChT-KD animals are more vulnerable to the effects of DEP in the lung.

Intestinal barrier dysfunction orchestrates the onset of inflammatory host-microbiome cross-talk in a human gut inflammation-on-a-chip.

The initiation of intestinal inflammation involves complex intercellular cross-talk of inflammatory cells, including the epithelial and immune cells, and the gut microbiome. This multicellular complexity has hampered the identification of the trigger that orchestrates the onset of intestinal inflammation. To identify the initiator of inflammatory host-microbiome cross-talk, we leveraged a pathomimetic "gut inflammation-on-a-chip" undergoing physiological flow and motions that recapitulates the pathophysiology of dextran sodium sulfate (DSS)-induced inflammation in murine models. DSS treatment significantly impaired, without cytotoxic damage, epithelial barrier integrity, villous microarchitecture, and mucus production, which were rapidly recovered after cessation of DSS treatment. We found that the direct contact of DSS-sensitized epithelium and immune cells elevates oxidative stress, in which the luminal microbial stimulation elicited the production of inflammatory cytokines and immune cell recruitment. In contrast, an intact intestinal barrier successfully suppressed oxidative stress and inflammatory cytokine production against the physiological level of lipopolysaccharide or nonpathogenic Escherichia coli in the presence of immune elements. Probiotic treatment effectively reduced the oxidative stress, but it failed to ameliorate the epithelial barrier dysfunction and proinflammatory response when the probiotic administration happened after the DSS-induced barrier disruption. Maintenance of epithelial barrier function was necessary and sufficient to control the physiological oxidative stress and proinflammatory cascades, suggesting that "good fences make good neighbors." Thus, the modular gut inflammation-on-a-chip identifies the mechanistic contribution of barrier dysfunction mediated by intercellular host-microbiome cross-talk to the onset of intestinal inflammation.