Severe Intestinal Inflammation Research Articles

Colonic crypt stem cell functions are controlled by tight junction protein claudin-7 through Notch/Hippo signaling.

The tight junction protein claudin-7 is essential for tight junction function and intestinal homeostasis. Cldn7 deletion in mice leads to an inflammatory bowel disease-like phenotype exhibiting severe intestinal epithelial damage, weight loss, inflammation, mucosal ulcerations, and epithelial hyperplasia. Claudin-7 has also been shown to be involved in cancer metastasis and invasion. Here, we test our hypothesis that claudin-7 plays an important role in regulating colonic intestinal stem cell function. Conditional knockout of Cldn7 in the colon led to impaired epithelial cell differentiation, hyperproliferative epithelium, a decrease in active stem cells, and dramatically altered gene expression profiles. In 3D colonoid culture, claudin-7-deficient crypts were unable to survive and form spheroids, emphasizing the importance of claudin-7 in stem cell survival. Inhibition of the Hippo pathway or activation of Notch signaling partially rescued the defective stem cell behavior. Concurrent Notch activation and Hippo inhibition resulted in restored colonoid survival, growth, and differentiation to the level comparable to those of wild-type derived crypts. In this study, we highlight the essential role of claudin-7 in regulating Notch and Hippo signaling-dependent colonic stem cell functions, including survival, self-renewal, and differentiation. These new findings may shed light on potential avenues to explore for drug development in colorectal cancer.

Milk: A Natural Guardian for the Gut Barrier.

The gut barrier plays an important role in health maintenance by preventing the invasion of dietary pathogens and toxins. Disruption of the gut barrier can cause severe intestinal inflammation. As a natural source, milk is enriched with many active constituents that contribute to numerous beneficial functions, including immune regulation. These components collectively serve as a shield for the gut barrier, protecting against various threats such as biological, chemical, mechanical, and immunological threats. This comprehensive review delves into the active ingredients in milk, encompassing casein, α-lactalbumin, β-lactoglobulin, lactoferrin, the milk fat globular membrane, lactose, transforming growth factor, and glycopeptides. The primary focus is to elucidate their impact on the integrity and function of the gut barrier. Furthermore, the implications of different processing methods of dairy products on the gut barrier protection are discussed. In conclusion, this study aimed to underscore the vital role of milk and dairy products in sustaining gut barrier health, potentially contributing to broader perspectives in nutritional sciences and public health.

Pericytes modulate endothelial inflammatory response during bacterial infection.

A previously unknown mechanism by which pericytes modulate inflammation was discovered. The absence of pericytes or blocking interaction between pericytes and endothelium through connexin 43 results in stronger inflammation, which shifts our understanding of pericyte biology, from a structural cell to a player in controlling inflammation.

Canagliflozin ameliorates ulcerative colitis via regulation of TLR4/MAPK/NF-κB and Nrf2/PPAR-γ/SIRT1 signaling pathways

Ulcerative colitis (UC) is one of the most common subtypes of inflammatory bowel disease (IBD) that affects the colon and is characterized by severe intestinal inflammation. Canagliflozin is a widely used antihyperglycemic agent, a sodium-glucose cotransporter-2 (SGLT2) inhibitor that enhances urinary glucose excretion. This study aims to provide insights into the potential benefits of canagliflozin as a treatment for UC by addressing possible cellular signals. Acetic acid (AA; 4% v/v) was administered intrarectally to induce colitis. Canagliflozin is given orally at a dose of 10 mg/kg/day. Canagliflozin attenuates inflammation in AA-induced colitis, evidenced by significant and dose-dependently downregulation of p38 MAPK, NF-κB-p65, IKK, IRF3, and NADPH-oxidase as well as colonic levels of IL-6 and IL-1β and MPO enzymatic activity. Canagliflozin mitigates colonic oxidative stress by decreasing MDA content and restoring SOD enzymatic activities and GSH levels mediated by co-activating of Nrf2, PPARγ, and SIRT1 pathways. Moreover, an in-silico study confirmed that canagliflozin was specific to all target proteins in this study. Canagliflozin's binding affinity with its target proteins indicates and confirms its effectiveness in regulating these pathways. Also, network pharmacology analysis supported that canagliflozin potently attenuates UC via a multi-target and multi-pathway approach.

Astragalus polysaccharide protects experimental colitis through an aryl hydrocarbon receptor-dependent autophagy mechanism.

Disruption of intestinal barriers plays a vital role in the pathogenesis of colitis. The aryl hydrocarbon receptor (AhR) is a recognition sensor that mediates intestinal immune homeostasis and minimizes intestinal inflammation. Astragalus polysaccharide (APS) exerts pharmacological actions in colitis; however, the mechanism has not been elucidated. We investigated whether APS protects through AhR-dependent autophagy. The symptoms of dextran sulfate sodium (DSS)-induced colitis in mice involving intestinal barrier function and inflammatory injury were evaluated after APS administration. Intestinal-specific Becn1 conditional knockout (Becn1 cKO) mice were constructed and compared with wild-type mice. Autophagy and the effects of APS were investigated after the deactivation of AhRs. The relationship between APS-induced AhRs and autophagic Becn1 was investigated using a dual-luciferase reporter system and chromatin immunoprecipitation (ChIP)-quantitative polymerase chain reaction assay. Caco-2 cells were used to investigate inflammatory responses and AhR-dependent autophagy. APS improved intestinal barrier function in inflammatory injury in colitis mice. APS triggered autophagic flow; however, knockout of Becn1 in the gut increased susceptibility to colitis, leading to diminished epithelial barrier function and severe intestinal inflammation, impairing the protective effects of APS. Mechanistically, APS-triggered autophagy depends on AhR expression. Activated AhR binds to the promoter Becn1 to operate transcription of genes involved in anti-inflammation and intestinal barrier repair, while deactivation of AhR correlated with intestinal inflammation and the therapeutic function of APS. APS protects colitis mice by targeting autophagy, especially as the AhR stimulates the repair of damaged intestinal barrier functions.

Paneth cells protect intestinal stem cell niche to alleviate deoxynivalenol-induced intestinal injury

Deoxynivalenol (DON) is a common toxin in grains and feeds, and DON exposure triggers severe small intestinal injury and inflammation, which harms the health of humans and livestock. DON treatment leads to a decrease in Paneth cells, whereas the role of Paneth cells in DON-induced intestinal injury is poorly understood. We utilized dithizone (40 mg/kg) to keep murine Paneth cell number at a low level. The results showed that dithizone-mediated long-term disruption of Paneth cells aggravated intestinal injury, intestinal stem cell (ISC) loss, and microbiota disorder in DON (2 mg/kg)-treated mice. Unexpectedly, the number of goblet cells and proliferative cells was boosted in mice treated with dithizone and DON. After dithizone and DON treatments, the Firmicutes/Bacteroidetes (F/B) ratio was reduced, and the increased abundance of Dubosiella and the decreased abundance of Lactobacillus were observed in mice. The functional recovery of Paneth cells by lysozyme (200 U/day) supplementation improved intestinal injury and ISC loss in mice after DON challenge. In addition, lysozyme also promoted the growth and ISC activity of intestinal organoids. Taken together, these results demonstrate the protective role of Paneth cells in DON-induced intestinal injury. Our study raises a novel target, Paneth cell, for the treatment of DON exposure.

TRAF5 regulates intestinal mucosal Th1/Th17 cell immune responses via Runx1 in colitis mice.

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disease associated with CD4+ Th1 and Th17 cell immune responses. Tumour necrosis factor-associated factor 5 (TRAF5) deficiency has been shown to aggravate DSS-induced colitis. However, the potential role of TRAF5 in regulating CD4+ T cell immune responses in the pathogenesis of IBD remains unclear. TRAF5-/- CD4+ CD45RBhigh T cells and WT CD4+ CD45RBhigh T cells were transferred to Rag2-/- mice via intravenous (i.v.) tail injection, respectively, to establish a chronic colitis model. Adeno-associated virus (AAV)-mediated gene knockout technique was used to knock out runt-associated transcription factor 1 (Runx1) expression in vivo. Specific cytokines of Th1 and Th17 cells were detected by quantitative RT-PCR, immunohistochemistry, ELISA, and flow cytometry. In T-cell transfer colitis mice, the Rag2-/- mice reconstituted with TRAF5-/- CD4+ CD45RBhigh T cells showed more severe intestinal inflammation than the WT control group, which was characterised by increased expression of INF-γ, TNF-α, IL-17a. Furthermore, we found that the INF-γ+ CD4+ , IL17a+ CD4+ , and INF-γ+ IL17a+ CD4+ T cells in the intestinal mucosa of Rag2-/- mice reconstituted with TRAF5-/- CD4+ CD45RBhigh T cells were significantly higher than those of the WT control group by flow cytometry. Mechanistically, knockout Runx1 inhibited the differentiation of TRAF5-/- CD4+ T cells into Th1 and Th17 cells in the intestinal mucosa of T-cell transfer colitis mice. TRAF5 regulates Th1 and Th17 cell differentiation and immune response through Runx1 to participate in the pathogenesis of colitis. Thus targeting TRAF5 in CD4+ T cells may be a novel treatment for IBD.

Maternal Western diet mediates susceptibility of offspring to Crohn’s-like colitis by deoxycholate generation

BackgroundThe Western dietary pattern, characterized by high consumption of fats and sugars, has been strongly associated with an increased risk of developing Crohn’s disease (CD). However, the potential impact of maternal obesity or prenatal exposure to a Western diet on offspring’s susceptibility to CD remains unclear. Herein, we investigated the effects and underlying mechanisms of a maternal high-fat/high-sugar Western-style diet (WD) on offspring’s susceptibility to 2,4,6-Trinitrobenzenesulfonic acid (TNBS)-induced Crohn’s-like colitis.MethodsMaternal dams were fed either a WD or a normal control diet (ND) for eight weeks prior to mating and continued throughout gestation and lactation. Post-weaning, the offspring were subjected to WD and ND to create four groups: ND-born offspring fed a normal diet (N–N) or Western diet (N-W), and WD-born offspring fed a normal (W–N) or Western diet (W-W). At eight weeks of age, they were administered TNBS to induce a CD model.ResultsOur findings revealed that the W–N group exhibited more severe intestinal inflammation than the N–N group, as demonstrated by a lower survival rate, increased weight loss, and a shorter colon length. The W–N group displayed a significant increase in Bacteroidetes, which was accompanied by an accumulation of deoxycholic acid (DCA). Further experimentation confirmed an increased generation of DCA in mice colonized with gut microbes from the W–N group. Moreover, DCA administration aggravated TNBS-induced colitis by promoting Gasdermin D (GSDMD)-mediated pyroptosis and IL-1beta (IL-1β) production in macrophages. Importantly, the deletion of GSDMD effectively restrains the effect of DCA on TNBS-induced colitis.ConclusionsOur study demonstrates that a maternal Western-style diet can alter gut microbiota composition and bile acid metabolism in mouse offspring, leading to an increased susceptibility to CD-like colitis. These findings highlight the importance of understanding the long-term consequences of maternal diet on offspring health and may have implications for the prevention and management of Crohn’s disease.5QpfrGmZ82qRXNutofRZ7nVideo

Tetramerization of STAT5 regulates monocyte differentiation and the dextran sulfate sodium-induced colitis in mice.

In response to external stimuli during immune responses, monocytes can have multifaceted roles such as pathogen clearance and tissue repair. However, aberrant control of monocyte activation can result in chronic inflammation and subsequent tissue damage. Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces monocyte differentiation into a heterogenous population of monocyte-derived dendritic cells (moDCs) and macrophages. However, the downstream molecular signals that dictate the differentiation of monocytes under pathological conditions is incompletely understood. We report here that the GM-CSF-induced STAT5 tetramerization is a critical determinate of monocyte fate and function. Monocytes require STAT5 tetramers to differentiate into moDCs. Conversely, the absence of STAT5 tetramers results in a switch to a functionally distinct monocyte-derived macrophage population. In the dextran sulfate sodium (DSS) model of colitis, STAT5 tetramer-deficient monocytes exacerbate disease severity. Mechanistically, GM-CSF signaling in STAT5 tetramer-deficient monocytes results in the overexpression of arginase I and a reduction in nitric oxide synthesis following stimulation with lipopolysaccharide. Correspondingly, the inhibition of arginase I activity and sustained supplementation of nitric oxide ameliorates the worsened colitis in STAT5 tetramer-deficient mice. This study suggests that STAT5 tetramers protect against severe intestinal inflammation through the regulation of arginine metabolism.

S-adenosyl-L-methionine supplementation alleviates damaged intestinal epithelium and inflammatory infiltration caused by Mat2a deficiency.

Methionine is important for intestinal development and homeostasis in various organisms. However, the underlying mechanisms are poorly understood. Here, we demonstrate that the methionine adenosyltransferase gene Mat2a is essential for intestinal development and that the metabolite S-adenosyl-L-methionine (SAM) plays an important role in intestinal homeostasis. Intestinal epithelial cell (IEC)-specific knockout of Mat2a exhibits impaired intestinal development and neonatal lethality. Mat2a deletion in the adult intestine reduces cell proliferation and triggers IEC apoptosis, leading to severe intestinal epithelial atrophy and intestinal inflammation. Mechanistically, we reveal that SAM maintains the integrity of differentiated epithelium and protects IECs from apoptosis by suppressing the expression of caspases 3 and 8 and their activation. SAM supplementation improves the defective intestinal epithelium and reduces inflammatory infiltration sequentially. In conclusion, our study demonstrates that methionine metabolism and its intermediate metabolite SAM play essential roles in intestinal development and homeostasis in mice.

GPR120 promotes neutrophil control of intestinal bacterial infection

ABSTRACT G-protein coupled receptor 120 (GPR 120) has been implicated in anti-inflammatory functions. However, how GPR120 regulates the neutrophil function remains unknown. This study investigated the role of GPR120 in the regulation of neutrophil function against enteric bacteria. 16S rRNA sequencing was used for measuring the gut microbiota of wild-type (WT) mice and Gpr120 −/− mice. Citrobacter rodentium infection and dextran sulfate sodium (DSS)-induced colitis models were performed in WT and Gpr120 −/− mice. Mouse peritoneal-derived primary neutrophils were used to determine the neutrophil functions. Gpr120 −/− mice showed altered microbiota composition. Gpr120 −/− mice exhibited less capacity to clear intestinal Citrobacter rodentium and more severe intestinal inflammation upon infection or DSS insults. Depletion of neutrophils decreased the intestinal clearance of Citrobacter rodentium. GPR120 agonist, CpdA, enhanced WT neutrophil production of reactive oxygen species (ROS) and extracellular traps (NETs), and GPR120-deficient neutrophils demonstrated a lower level of ROS and NETs. CpdA-treated neutrophils showed an enhanced capacity to inhibit the growth of Citrobacter rodentium, which was abrogated by the inhibition of either NETs or ROS. CpdA promoted neutrophil inhibition of the growth of commensal bacteria Escherichia coli O9:H4 and pathobiont Escherichia coli O83:H1 isolated from a Crohn’s disease patient. Mechanically, mTOR activation and glycolysis mediated GPR120 induction of ROS and NETs in neutrophils. Additionally, CpdA promoted the neutrophil production of IL-17 and IL-22, and treatment with a conditioned medium of GPR120-activated neutrophils increased intestinal epithelial cell barrier functions. Our study demonstrated the critical role of GPR120 in neutrophils in protection against enteric bacterial invasion.

Evidence for a Causal Role for Escherichia coli Strains Identified as Adherent-Invasive (AIEC) in Intestinal Inflammation.

Enrichment of adherent-invasive Escherichia coli (AIEC) has been consistently detected in subsets of inflammatory bowel disease (IBD) patients. Although some AIEC strains cause colitis in animal models, these studies did not systematically compare AIEC with non-AIEC strains, and causal links between AIEC and disease are still disputed. Specifically, it remains unclear whether AIEC shows enhanced pathogenicity compared to that of commensal E. coli found in the same ecological microhabitat and if the in vitro phenotypes used to classify strains as AIEC are pathologically relevant. Here, we utilized in vitro phenotyping and a murine model of intestinal inflammation to systematically compare strains identified as AIEC with those identified as non-AIEC and relate AIEC phenotypes to pathogenicity. Strains identified as AIEC caused, on average, more severe intestinal inflammation. Intracellular survival/replication phenotypes routinely used to classify AIEC positively correlated with disease, while adherence to epithelial cells and tumor necrosis factor alpha production by macrophages did not. This knowledge was then applied to design and test a strategy to prevent inflammation by selecting E. coli strains that adhered to epithelial cells but poorly survived/replicated intracellularly. Two E. coli strains that ameliorated AIEC-mediated disease were subsequently identified. In summary, our results show a relationship between intracellular survival/replication in E. coli and pathology in murine colitis, suggesting that strains possessing these phenotypes might not only become enriched in human IBD but also contribute to disease. We provide new evidence that specific AIEC phenotypes are pathologically relevant and proof of principle that such mechanistic information can be therapeutically exploited to alleviate intestinal inflammation. IMPORTANCE Inflammatory bowel disease (IBD) is associated with an altered gut microbiota composition, including expansion of Proteobacteria. Many species in this phylum are thought to contribute to disease under certain conditions, including adherent-invasive Escherichia coli (AIEC) strains, which are enriched in some patients. However, whether this bloom contributes to disease or is just a response to IBD-associated physiological changes is unknown. Although assigning causality is challenging, appropriate animal models can test the hypothesis that AIEC strains have an enhanced ability to cause colitis in comparison to other gut commensal E. coli strains and to identify bacterial traits contributing to virulence. We observed that AIEC strains are generally more pathogenic than commensal E. coli and that bacterial intracellular survival/replication phenotypes contributed to disease. We also found that E. coli strains lacking primary virulence traits can prevent inflammation. Our findings provide critical information on E. coli pathogenicity that may inform development of IBD diagnostic tools and therapies.

Novel evaluation indicators of MOG35∼55 induced experimental autoimmune encephalomyelitis in C57BL/6J mice

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS), characterized by demyelinating neuropathy. Despite a long period of research on the immune mechanisms involved in CNS diseases, the etiology of MS remains unknown. MS may present with different clinical and pathological manifestations due to the involvement of different pathogenic processes, including balance and mobility disorders, psychiatric abnormalities, and intestinal dysfunction. We used an animal model of MS, experimental autoimmune encephalomyelitis (EAE), to assess clinical symptoms of MS with the aim of creating new indicators for the assessment of EAE. Our results show that EAE mice develop severe bone loss, anxiety-like moods, and intestinal inflammation in addition to clinical phenomena such as inflammatory infiltration and demyelination of the spinal cord. Our new indicators aim to provide a more comprehensive assessment of MS to avoid the pitfalls of a single intervention and also to provide a more systematic assessment of the effectiveness of drugs used to treat MS.

Outcome of patients with primary sclerosing cholangitis and ulcerative colitis undergoing colectomy

Background and Aim: Patients with ulcerative colitis (UC) are at risk of developing primary sclerosing cholangitis (PSC). As a form of continence preservation, ileal pouch-anal anastomosis or ileorectal anastomosis are used for patients undergoing colectomy. The present study aimed to determine the patient outcomes following colectomy for primary sclerosing cholangitis and ulcerative colitis. Patients and Methods: 64 patients with PSC and UC undergoing colectomy were enrolled and investigated in the Department of Gastroenterology, Lady Reading Hospital, Peshawar from January 2018 to June 2020. Study protocol was approved by the institutional research and ethical committee. Patient’s data regarding clinical information, preoperative liver tests, colectomy date, pathological findings, and follow-up liver tests were reviewed from medical records. The colectomy-leading indications such as colonic dysplasia, bowel perforation, and colonic inflammation etc. were recorded. Several preoperative tests were conducted, including total bilirubin, albumin levels, direct bilirubin and ALP. SPSS version 26 was used for data analysis. Results: The overall mean age was 40.42±3.6 years. Of the total 64 patients, there were 42 (65.6%) male and 22 (34.4%) females. Colectomy was most commonly indicated by severe intestinal inflammation (52%), bowel perforations (4%), and dysplastic colons (38%). The incidence of postoperative complications were 43.8% (n=28).

TOXIC EPIDERMAL NECROLYSIS IN A PATIENT WITH GRAFT-VERSUS-HOST DISEASE

<h3>Introduction</h3> Toxic epidermal necrolysis (TEN) is a type 4 hypersensitivity reaction leading to extensive skin detachment. TEN occurs 1-3 weeks after offending drug exposure and shares clinical similarities with grade IV graft-versus-host disease (GVHD). We present a case of TEN in a patient with previously diagnosed GVHD, with suspecting culprit agents being oxacillin or oral vancomycin. <h3>Case Description</h3> A 59-year-old man with a history of primary myelofibrosis status-post allogeneic stem-cell transplant complicated by GVHD was evaluated for new-onset desquamative rash. He initially presented with MSSA sepsis, for which oxacillin was administered. His course was complicated by C. difficile colitis requiring oral vancomycin. The patient's rash involved 80% body surface area with tense bullae and denuded skin, Asboe-Hansen sign positive. He had leukopenia to 0.9 and his creatinine peaked at 4.0. Biopsy of this new eruption revealed bullous epidermal necrolytic dermatosis with pustulosis and notable absence of prior cellular infiltration, favoring TEN. His SCORTEN score was 4. He received supportive care including burn unit transfer, but was transitioned to comofort measures shortly thereafter. <h3>Discussion</h3> This case poses with two diagnostic challenges. First, the clinical overlap between grade IV GVHD and TEN highlights the diagnostic utility of biopsy which favored TEN as the etiology of this new eruption versus another flare of cutaneous GVHD. The proper diagnosis is important to direct care and discontinue implicated drugs. Second, while oxacillin seemed the most likely culprit, consideration was give to oral vancomycin as well, given his severe intestinal inflammation making systemic absorption possible.

The miR-181 family regulates colonic inflammation through its activity in the intestinal epithelium.

The intestinal epithelium is a key physical interface that integrates dietary and microbial signals to regulate nutrient uptake and mucosal immune cell function. The transcriptional programs that regulate intestinal epithelial cell (IEC) quiescence, proliferation, and differentiation have been well characterized. However, how gene expression networks critical for IECs are posttranscriptionally regulated during homeostasis or inflammatory disease remains poorly understood. Herein, we show that a conserved family of microRNAs, miR-181, is significantly downregulated in IECs from patients with inflammatory bowel disease and mice with chemical-induced colitis. Strikingly, we showed that miR-181 expression within IECs, but not the hematopoietic system, is required for protection against severe colonic inflammation in response to epithelial injury in mice. Mechanistically, we showed that miR-181 expression increases the proliferative capacity of IECs, likely through the regulation of Wnt signaling, independently of the gut microbiota composition. As epithelial reconstitution is crucial to restore intestinal homeostasis after injury, the miR-181 family represents a potential therapeutic target against severe intestinal inflammation.

Mechanosensory channel Piezo1 is essential in pathogenic T cell-mediated intestinal inflammation

Abstract Inflammatory bowel disease (IBD) is a chronic inflammatory disorder in the gastrointestinal tract. CD4+ T cells are especially known to be the main drivers of IBD when they show an elevated level of activation. Elevation of intracellular Ca2+ is one of the key triggering signals for T cell activation. Piezo1 is a mechanosensitive nonselective Ca2+-permeable cation channel, which is broadly expressed in mammalian cells. However, the role of Piezo1 in the pathogenesis of T cell-mediated colitis remains unknown. We have generated T cell-specific Piezo1 knockout (Piezo1fl/flxCD4-cre) mice and observed that loss of Piezo1 in CD4+ T cell increased Th1 and Th17 cell polarization. RNA-sequence analysis of Piezo1fl/flxCD4-cre T cells identified elevated pathogenic Th17 cell pathway, IFN-γ signaling pathways and inflammatory response gene signature compared to that of wild type. These results suggest that Piezo1 controls the inflammatory response of pathogenic T cells. Next, we examined the function of Piezo1 on intestinal inflammation in vivo using acute and chronic colitis mouse model. For the acute colitis mouse model, we used a chemically induced mouse model of colitis using DSS in drinking water. Piezo1fl/flxCD4-cre mice with DSS developed severe colitis compared to Piezo1fl/fl mice with DSS. However, in chronic colitis mouse model, which is the adaptive transfer of naïve CD4+ T cells (CD4+CD45RBhigh) from Piezo1fl/fl or Piezo1fl/flxCD4cre into Rag1−/− mice, T cells from Piezo1fl/flxCD4cre mice failed to induce colon inflammation, while mice that received T cells from Piezo1fl/fl mice developed severe intestinal inflammation. Thus, our data demonstrate a critical role of Piezo1 in CD4+ T cell-mediated intestinal inflammation. Supported by R03 CA230840, P30 CA043703, St. Baldrick’s Foundation, Hyundai Hope-on-Wheels Scholar Hope Grant, Andrew McDonough B+ Foundation, Curing Kids Cancer, Center for Pediatric Immunotherapy at Rainbow

P034 DISRUPTive liquid biopsies in Inflammatory Bowel Disease (DISRUPT-IBD): Release of exosomal and molecular tissue signals by transabdominal ultrasound?

Abstract Background A major drawback in diagnosis and monitoring of IBD are insufficient biomarkers that do not correlate well with tissue disease activity. Inflammation and cellular stress lead to an increased release of exosomes (Lipinski et al, 2019, EMBO J) carrying inflammatory signal proteins as cargo (Wozniak et al, 2020, J Cell Biol). Interestingly, colorectal cancer cells strongly release tumor markers after stimulation by sonography waves, probably through the disruptive energy of standard ultrasound (D’Souza et al, 2009, PNAS). We thus hypothesize that application of ultrasound waves on inflamed intestinal tissue in active IBD induces the release of tissue-specific exosomes that can be detected in the peripheral blood and used as novel biomarkers. Methods 26 patients with different degrees of disease activity and various ongoing therapies with IBD were included in a pilot trial. Serum was taken before and 30 minutes after diagnostic transabdominal ultrasound. Serum exosomes were precipitated (using ExoQuick) and exosomal (exo-)miRNA were isolated for miRNA sequencing using SeraMir protocol. Exosomal proteins were isolated for quantification of inflammatory markers (as exosomal cargo). Results We found a correlation between exo-miRNA concentration and disease severity, determined by clinical assessment scores and sonographic findings. Exo-miRNA sequencing revealed a select few miRNAs to be induced by sonography. However, the overall composition of annotated miRNA transcripts did not separate samples according to sampling timepoints. Among these “inducible” exo-miRNA, we found hsa-miR-942, which is involved in cell cycle and Wnt signaling in intestinal epithelial cells, to be significantly induced in higher grade intestinal inflammation. The exosomal protein concentrations did not correlate with disease severity at baseline, but were increased after sonography in severe intestinal inflammation. We did not find markers of the inflammasome apparatus as inducible exosomal cargos. Conclusion Sonography-induced exosomal markers, e.g., exo-miRNAs, could become novel biomarkers for intestinal inflammation in IBD. Further exploration of the functional role of inducible biomarkers and continued investigation of exosomal miRNA and protein profiling will be performed.

Vibrio cholerae was found in cultured bullfrog.

Bullfrog is one of the most important economic aquatic animals in China that is widely cultured in southern China and is a key breed recommended as an industry of poverty alleviation in China. During recent years, a fatal bacterial disease has often been found in cultured bullfrogs. The clinical manifestations of the diseased bullfrogs were severe intestinal inflammation and an anal prolapse. A bacterial pathogen was isolated from the diseased bullfrog intestines. The bacterium was identified as Vibrio cholerae using morphological, biochemical and 16S rRNA phylogenetic analysis. In this study, V. cholerae was isolated and identified in diseased bullfrogs for the first time, providing a basis for the diagnosis and control of the disease. Therefore, attention should be paid to the modes of transmission of V. cholerae from bullfrog and formulate reasonable safety measures.

Oxytocin suppresses epithelial cell-derived cytokines production and alleviates intestinal inflammation in food allergy

Food allergy is a growing healthcare problem worldwide, but prophylactic options and regulatory therapies are limited. Oxytocin (OXT), conventionally acknowledged as a hormone, was recently proven to have potent anti-inflammatory and immunomodulatory activities in certain diseases. Here, we reported the novel function and its underlying mechanisms of OXT on food allergy in vivo and in vitro. We showed that the levels of OXT were elevated in ovalbumin (OVA)-allergic mice and patients with food allergy. In HT-29 cells, OXT inhibited the production of the epithelial cell-derived cytokines thymic stromal lymphopoietin (TSLP), interleukin (IL)-25 and IL-33 by suppressing NF-κB signaling, in which β-arrestin2 participated. These functions of OXT were abolished by oxytocin receptor (OXTR) depletion. Treating OVA-induced BALB/c mice with OXT suppressed TSLP, IL-25 and IL-33 production and attenuated systemic anaphylaxis and intestinal inflammation. OXTR-/- mice showed extreme increases in TSLP, IL-25 and IL-33 levels as well as severe systemic anaphylaxis and intestinal inflammation. In conclusion, through OXTRs, OXT has a promising antiallergic effect on experimental food allergy by suppressing epithelial TSLP, IL-25 and IL-33 production via inhibiting NF-κB signaling and upregulating β-arrestin2 expression. Our study provides a new therapeutic perspective for food allergy in humans.