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Obesity is an established risk factor for many diseases including intestinal cancer. One of the responsible mechanisms is the chronic inflammation driven by obesity. However, it remains to be defined whether diet-induced obesity exacerbates the intestinal inflammatory status by cytokines produced in adipose tissue or the high fat diet first alters the gut microbiota and then drives intestinal inflammation. To address this question, we fed C57BL/6 mice with a high fat diet (HF, 60%) and sacrificed them sequentially after 8, 12, and 16 weeks, and then compositions of gut microbiota and expressions of antimicrobial peptides were determined. The compositions of gut microbiota were altered at 8 wk HF feeding, followed with reduced Paneth antimicrobial peptides lysozyme and Reg IIIγ after 12 and 16 wk HF feeding (p<0.05), whereas elevations of circulating inflammatory cytokines IFNγ and TNF-α were observed until feeding a HF diet for 16 weeks (p<0.05). These results indicated that high fat diet may stimulate intestinal inflammation via altering gut microbiota, and it occurs prior to the potential influence by circulating inflammatory cytokines. These findings emphasized the importance of microbiota, in addition to adipose tissue per se, in driving intestinal inflammation, which may thereafter promote intestinal tumorigenesis. [ABSTRACT FROM AUTHOR]

The cytokine TNF drives inflammatory diseases, e.g., Crohn's disease. In a mouse model of TNF‐induced systemic inflammatory response syndrome (SIRS), severe impact on intestinal epithelial cells (IECs) is observed. Zinc confers complete protection in this model. We found that zinc no longer protects in animals which lack glucocorticoids (GCs), or express mutant versions of their receptor GR in IECs, nor in mice which lack gut microbiota. RNA‐seq studies in IECs showed that zinc caused reduction in expression of constitutive (STAT1‐induced) interferon‐stimulated response (ISRE) genes and interferon regulatory factor (IRF) genes. Since some of these genes are involved in TNF‐induced cell death in intestinal crypt Paneth cells, and since zinc has direct effects on the composition of the gut microbiota (such as several Staphylococcus species) and on TNF‐induced Paneth cell death, we postulate a new zinc‐related anti‐inflammatory mechanism. Zinc modulates the gut microbiota, causing less induction of ISRE/IRF genes in crypt cells, less TNF‐induced necroptosis in Paneth cells, and less fatal evasion of gut bacteria into the system. Synopsis: This study provides genetic and biochemical evidence that the intestinal health promoting effects of zinc supplementation is based on a specific, direct effect on members of the microbial community in the ileum. The cytokine TNF has dramatic effects on the viability of ileal crypt Paneth cellsThe TNF effect depends on expression of Interferon Stimulated Response Element (ISRE) and Interferon Regulatory Factor (IRF) genes which are induced by gut microbesBy killing bacteria such as several Staphylococci species, zinc reduces this ISRE/IRF expression, preventing Paneth cell death during inflammationSince glucocorticoids, like dexamethasone, reduce ISRE/IRF on the transcriptional level, zinc works in concert with such steroids [ABSTRACT FROM AUTHOR]

The IκB kinase (IKK)–NF‐κB signaling pathway plays a multifaceted role in inflammatory bowel disease (IBD): on the one hand, it protects from apoptosis; on the other, it activates transcription of numerous inflammatory cytokines and chemokines. Although several murine models of IBD rely on disruption of IKK–NF‐κB signaling, these involve either knockouts of a single family member of NF‐κB or of upstream kinases that are known to have additional, NF‐κB‐independent, functions. This has made the distinct contribution of NF‐κB to homeostasis in intestinal epithelium cells difficult to assess. To examine the role of constitutive NF‐κB activation in intestinal epithelial cells, we generated a mouse model with a tissue‐specific knockout of the direct inhibitor of NF‐κB, Nfkbia/IκBα. We demonstrate that constitutive activation of NF‐κB in intestinal epithelial cells induces several hallmarks of IBD including increased apoptosis, mucosal inflammation in both the small intestine and the colon, crypt hyperplasia, and depletion of Paneth cells, concomitant with aberrant Wnt signaling. To determine which NF‐κB‐driven phenotypes are cell‐intrinsic, and which are extrinsic and thus require the immune compartment, we established a long‐term organoid culture. Constitutive NF‐κB promoted stem‐cell proliferation, mis‐localization of Paneth cells, and sensitization of intestinal epithelial cells to apoptosis in a cell‐intrinsic manner. Increased number of stem cells was accompanied by a net increase in Wnt activity in organoids. Because aberrant Wnt signaling is associated with increased risk of cancer in IBD patients and because NFKBIA has recently emerged as a risk locus for IBD, our findings have critical implications for the clinic. In a context of constitutive NF‐κB, our findings imply that general anti‐inflammatory or immunosuppressive therapies should be supplemented with direct targeting of NF‐κB within the epithelial compartment in order to attenuate apoptosis, inflammation, and hyperproliferation. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Background: Different studies have shown the key role of endoplasmic reticulum (ER) stress in autoimmune and chronic inflammatory disorders, as well as in neurodegenerative diseases. ER stress leads to the formation of misfolded proteins which affect the secretion of different cell types that are crucial for the intestinal homeostasis. Purpose: In this review, we discuss the role of ER stress and its involvement in the development of inflammatory bowel diseases, chronic conditions that can cause severe damage of the gastrointestinal tract, focusing on the alteration of Paneth cells and goblet cells (the principal secretory phenotypes of the intestinal epithelial cells). ER stress is also discussed in the context of neurodegenerative diseases, in which protein misfolding represents the signature mechanism. ER stress in the bowel and consequent accumulation of misfolded proteins might represent a bridge between bowel inflammation and neurodegeneration along the gut‐to‐brain axis, affecting intestinal epithelial homeostasis and the equilibrium of the commensal microbiota. Targeting intestinal ER stress could foster future studies for designing new biomarkers and new therapeutic approaches for neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Interleukin-22 (IL-22) is an important cytokine in the intestinal environment. IL-22 is mainly produced by immune cells and targeted at nonimmune cells such as epithelial and stromal cells in a broad array of tissues such as - but not restricted to- the liver and adipose tissue. IL-22 therefore connects immune functions with metabolic functions of the host, and since it is induced by the microbiota, connects host functioning to the outside environment. IL-22 induces epithelial cell proliferation aiding in rapid epithelium regeneration and wound healing. Additionally, IL-22 activates antiapoptotic genes and DNA damage response pathways, enhancing epithelial cell survival. Recently, it has also been shown that IL-22 induces Paneth cell differentiation in humans. However, IL-22 can also contribute to intestinal epithelium damage and reduces microbial diversity in the intestine directly or indirectly by inducing excessive antimicrobial peptide production by epithelial cells. Moreover, IL-22 enhances angiogenesis and may therefore support tumorigenesis in the intestine. In conclusion, it appears that whether IL-22 has a beneficial or harmful effect in the mammalian intestine largely depends on its regulation. This review aims to provide a comprehensive overview of the current literature and emphasizes that IL-22 signaling outcome depends on the timing and duration of IL-22 production, the presence of it regulators such as IL-22BP, and the specific location of the cytokine production in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

The discovery that polymorphisms in the NOD2 (nucleotide-binding oligomerization domain containing 2) gene are associated with a greatly increased risk for the development of Crohn's disease has provided a means to achieve a deeper understanding of the dysregulation of mucosal immune responses to the commensal intestinal organisms that is thought to underlie this disease. NOD2 is a NOD-like receptor ( NLR) family member that senses and responds to bacterial wall peptides; thus, the most widely held view of the relation of the NOD2 polymorphisms with Crohn's disease is that these polymorphisms lead to deficient immune responses to gut bacteria, and these, in turn, lead to quantitative or qualitative changes in the bacterial population in the gut lumen or lamina propria that cause inflammation at this site. Initially, this view was based mainly on the observation that defective NOD2 function can result in reduced α-defensin production by intestinal Paneth cells and that such impairment leads to loss of host defense against gut bacteria. In this review, we reconsider this possibility and marshal evidence that it is not in fact likely to be a prime element of Crohn's disease causation. More recently, evidence has been accumulating that the NOD2 dysfunction leads to Crohn's inflammation by inducing changes in the gut microbiome that influence immune effector or regulatory function. We review the strengths and weaknesses of this emerging hypothesis. Finally, we consider the possibility that NOD2 dysfunction can lead to inflammation because of a second and somewhat overlooked aspect of its function, that as an immunoregulator of innate immune responses. In particular, we review the body of evidence that NOD2 stimulation activates a cross-tolerance response that downregulates and thus prevents excessive TLR responses that cause Crohn's inflammation. [ABSTRACT FROM AUTHOR]

The human gut barrier is the tissue exposed to the highest load of microorganisms, harbouring 100 trillion bacteria. In addition, the gut's renewal rate outruns that of any other human tissue. Antimicrobial peptides (AMPs) are highly optimized defense molecules in the intestinal barrier optimized to maintain gastrointestinal homeostasis. Alterations in AMPs activity can lead to or result from human gastrointestinal diseases. In this review, unique, conserved, or otherwise regular alterations in the expression patterns of human AMPs across gastrointestinal inflammatory and infectious diseases were analyzed for pattern elucidation. Human gastrointestinal diseases are associated with alterations in gut AMPs' expression patterns in a peptide‐specific, disease‐specific, and pathogen‐specific way, modulating human gastrointestinal functioning. Across diseases, there is a (i) marked reduction in otherwise constitutively expressed AMPs, leading to increased disease susceptibility, and a (ii) significant increase in the expression of inducible AMPs, leading to tissue damage and disease severity. Infections and inflammatory conditions are associated with altered gene expression in the gut, whose patterns may favour cellular metaplasia, mucosal dysfunction, and disease states. Altered expression of AMPs can thus thrive disease severity and evolution since its early stages. Nevertheless, the modulation of AMP expression patterns unveils promising therapeutic targets. [ABSTRACT FROM AUTHOR]

Background: Heavy alcohol consumption disrupts gut epithelial integrity, leading to increased permeability of the gastrointestinal tract and subsequent translocation of microbes. Regenerating islet‐derived protein 3α (REG3α) and Trefoil factor 3 (TFF3) are mainly secreted to the gut lumen by Paneth and Goblet cells, respectively, and are functionally linked to gut barrier integrity. Circulating levels of REG3α and TFF3 have been identified as biomarkers for gut damage in several human diseases. We examined whether plasma levels of REG3α and TFF3 were dysregulated and correlated with conventional markers of microbial translocation (MT) and pro‐inflammatory mediators in heavy drinkers with and without alcoholic hepatitis (AH). Methods: Cross‐sectional and longitudinal studies were performed to monitor plasma levels of REG3α and TFF3 in 79 AH patients, 66 heavy drinkers without liver disease (HDC), and 46 healthy controls (HC) at enrollment and at 6‐ and 12‐month follow‐ups. Spearman correlation was used to measure the relationships of REG3α and TFF3 levels with MT, disease severity, inflammation, and effects of abstinence from alcohol. Results: At enrollment, AH patients had significantly higher levels of REG3α and TFF3 than HDC and HC. The elevated REG3α levels were positively correlated with the 30‐day fatality rate. Plasma levels of REG3α and TFF3 in AH patients differentially correlated with conventional MT markers (sCD14, sCD163, and LBP) and several highly up‐regulated inflammatory cytokines/chemokines/growth factors. At follow‐ups, although REG3α and TFF3 levels were decreased in AH patients with alcohol abstinence, they did not fully return to baseline levels. Conclusions: Circulating levels of REG3α and TFF3 were highly elevated in AH patients and differentially correlated with AH disease severity, MT, and inflammation, thereby serving as potential biomarkers of MT and gut epithelial damage in AH patients. [ABSTRACT FROM AUTHOR]

Defensins are antimicrobial peptides produced at a variety of epithelial surfaces. In the intestinal tract, they contribute to host immunity and assist in maintaining the balance between protection from pathogens and tolerance to normal flora. However, attenuated expression of defensins compromises host immunity and hence may alter the balance toward inflammation. Altered defensin production is suggested to be an integral element in the pathogenesis of inflammatory bowel disease (IBD). Evidence for this is shown in Crohn's disease where reduced α-defensin levels are seen in patients with ileal disease and reduced β-defensin levels in those with colonic involvement. Further evidence is provided by research linking nucleotide oligomerization domain 2 (NOD2) mutations and deficient defensin expression. However, alternate studies suggest that NOD2 status and defensin expression are independent, and that defensin deficiency is due to mucosal surface destruction as a result of inflammatory changes, indicating that reduced defensin expression is a symptom of the disease and not the cause. Although it is clear that defensin expression is altered in IBD, it is less clear whether defensin deficiency is implicated in the pathogenesis of IBD or is a consequence of the disease process. The aim of this article is to review the current knowledge of defensins in IBD and discuss their potential role in IBD pathogenesis. [ABSTRACT FROM AUTHOR]

Mice deficient in intestinal epithelial TLR9 develop small intestinal Paneth cell hyperplasia and higher Paneth cell IL-17A levels. Since small intestinal Paneth cells and IL-17A play critical roles in hepatic ischemia reperfusion (IR) injury, we tested whether mice lacking intestinal TLR9 have increased hepatic IR injury. Mice lacking intestinal TLR9 had profoundly increased liver injury after hepatic IR compared to WT mice with exacerbated hepatocyte necrosis, apoptosis, neutrophil infiltration, and inflammatory cytokine generation. Moreover, we observed increased small intestinal inflammation and apoptosis after hepatic IR in intestinal TLR9 deficient mice. As a potential explanation for increased hepatic IR injury, fecal short-chain fatty acids butyrate and propionate levels were lower in intestinal TLR9 deficient mice. Suggesting a potential therapy for hepatic IR, exogenous administration of butyrate or propionate protected against hepatic IR injury in intestinal TLR9 deficient mice. Mechanistically, butyrate induced small intestinal IL-10 expression and downregulated the claudin-2 expression. Finally, IL-10 neutralization abolished the protective effects of butyrate against hepatic IR injury. Our studies show intestinal TLR9 deficiency results in exacerbated hepatic IR injury with increased small intestinal apoptosis and inflammation. Furthermore, short-chain fatty acids butyrate and propionate protect against hepatic IR injury and intestinal apoptosis/inflammation in intestinal TLR9 deficient mice. [ABSTRACT FROM AUTHOR]

Summary: Background: The inflammatory bowel diseases, Crohn's disease and ulcerative colitis are related multifactorial diseases. Their pathogenesis is influenced by each individual's immune system, the environmental factors within exposome and genetic predisposition. Smoking habit is the single best‐established environmental factor that influences disease phenotype, behaviour and response to therapy. Aim: To assess current epidemiological, experimental and clinical evidence that may explain how smoking impacts on the pathogenesis of inflammatory bowel disease. Methods: A Medline search for 'cigarette smoking', in combination with terms including 'passive', 'second‐hand', 'intestinal inflammation', 'Crohn's disease', 'ulcerative colitis', 'colitis'; 'intestinal epithelium', 'immune system', 'intestinal microbiota', 'tight junctions', 'mucus', 'goblet cells', 'Paneth cells', 'autophagy'; 'epigenetics', 'genes', 'DNA methylation', 'histones', 'short noncoding/long noncoding RNAs'; 'carbon monoxide/CO' and 'nitric oxide/NO' was performed. Results: Studies found evidence of direct and indirect effects of smoking on various parameters, including oxidative damage, impairment of intestinal barrier and immune cell function, epigenetic and microbiota composition changes, that contribute to the pathogenesis of inflammatory bowel disease. Conclusions: Cigarette smoking promotes intestinal inflammation by affecting the function and interactions among intestinal epithelium, immune system and microbiota/microbiome. [ABSTRACT FROM AUTHOR]

Although a chronic inflammation-carcinoma sequence has been proposed in cases of longstanding ulcerative colitis (UC), the relationship of morphological alteration or remodeling of regenerated mucosa to carcinoma development is yet to be clarified. Therefore, mucosae of 49 resected rectae from individuals with UC were histologically and quantitatively analyzed, with regard to thickness and morphological parameters of crypts, in relation to the disease duration, clinical disease activity and neoplastic development. An immunohistochemical examination of Ki-67, p53, p21WAF1 and ssDNA labeling was also included. Significant correlations of number, height, angle, fusion and Paneth cell metaplasia of crypts, as well as thickness of the muscularis mucosae, were revealed with disease duration, as confirmed by three-dimensional reconstructed image analysis. p53 and p21WAF1-positive cells increased with disease duration and were significantly more frequent in cases with neoplasia, suggesting more DNA damage. However, this was not the case for ssDNA labeling, assessed as an indicator of apoptosis. In general, histological changes and p53, p21WAF1 and Ki-67 labeling were correlated. In conclusion, histological parameters for mucosal remodeling correlate well with UC duration, indicating accumulation of structural alterations. Accumulated damage to DNA, reflected by increased p53 and p21WAF1 labeling indices, might be involved in cancer development, as well as longstanding inflammation. [ABSTRACT FROM AUTHOR]

Aims Autologous intestinal grafts are used to (re)create a vagina in selected patients. The risk of diversion colitis is mentioned as a disadvantage, although its prevalence remains unclear. This study aimed to assess the histopathological characteristics of the sigmoid-derived neovaginal epithelial lining after diverting surgery and correlate these with clinical findings. Methods and results Biopsy specimens were obtained from the epithelial lining of the sigmoid-derived neovagina and remaining rectosigmoid as regular follow-up from 26 patients with a median age of 22 years (range 19-52) and median postoperative follow-up of 13 months (range 6-52). Medical history, neovaginal symptoms and sexual activity were documented. An experienced gastrointestinal histopathologist assessed the specimens using a descriptive item-score, comprising signs of chronic and active inflammation. Inflammatory changes were observed in 21 (80.7%) neovaginal and one (3.8%) rectosigmoid specimens. The neovaginal appearance was characterized by an increase of lymphoid aggregates and lymphoplasmacellular infiltrate. Other common features were the presence of polymorphonuclear neutrophils and Paneth cell metaplasia. Neovaginal discharge was correlated with the presence of inflammatory changes ( P = 0.008, Spearman's rho = 0.506). Discussion Acute and chronic inflammation of the sigmoid-derived neovagina was commonly observed and consistent with a proposed diagnosis of diversion neovaginitis. Neovaginal discharge correlates with this histopathological entity. [ABSTRACT FROM AUTHOR]

The dermatological manifestations of the coronavirus cause severe acute respiratory syndrome. The current study investigates the morphological and histopathological relationship between the emergence of skin lesions and the severity of COVID‐19 across the course of the disease via a cross‐sectional study. There were skin lesions (maculopapular rash, vesiculobullous lesions, urticarial lesions, cutaneous thromboembolic "CT," and erythema multiforme‐like lesions "EM‐like") in confirmed COVID‐19 instances. A total of 150 patients of both sexes were evaluated morphologically and were classified as early (44% of the total) or late based on the emergence of respiratory symptoms (one week before or two weeks after, respectively). The early and late diagnostic groups represented 44% and 56% of the total patients, respectively. Patients with no skin lesion and one skin lesion showed a significant correlation with disease timeline early and late stages (X2 = 22.38, P < 0.001; X2 = 4.432, P < 0.001, respectively). CT and EM‐like were correlated with the disease severity, X2 = 50.51, P < 0.001; X2 = 19.186, P ≤ 0.001, respectively. In conclusion, our data suggested that the onset of dermatological lesions that developed during the COVID‐19 pandemic may be a useful diagnostic and prognostic tool for COVID‐19 severity. Therefore, a thorough examination of the skin may save time and bring physicians to an accurate diagnosis and, as a result, prompt treatment. [ABSTRACT FROM AUTHOR]

Apoptosis and autophagy are dynamic processes that determine the fate of cells. Vitamin D receptor (VDR) deficiency in the intestine leads to abnormal Paneth cells and impaired autophagy function. Here, we will elucidate the mechanisms of the intestinal epithelial VDR regulation of autophagy and apoptosis. We used in vivo VDRlox and VDR∆IEC mice and ex vivo organoids generated from small intestine and colon tissues. We found that VDR deficiency induced more apoptotic cells and significantly increased cell death in the small intestine and colon of VDR∆IEC mice. The proapoptotic protein B-cell lymphoma 2 (BCL-2) associated X protein (Bax) was enhanced, whereas autophagy related 16 like 1 (ATG16L1) and Beclin-1 were decreased in the intestines of VDRΔIEC mice. Apoptosis induced by Bax reduced autophagy by decreasing Beclin-1. Physical interactions between Beclin-1 and Bcl-2 were increased in the VDR-deficient epithelia from mice. The growth of VDR∆IEC organoids was significantly slower with fewer Paneth cells than that of VDR+/+ organoids. The expression levels of Beclin-1 and lysozyme were decreased in VDR∆IEC organoids. Bacterial endotoxin levels were high in the serum from VDR∆IEC mice and made mice susceptible to colitis. In the organoids and colitis IL-10-/- mice, vitamin D3 treatment increased VDR and ATG16L1 protein expression levels, which activated autophagic responses. In summary, intestinal epithelial VDR regulates autophagy and apoptosis through ATG16L1 and Beclin-1. Our studies provide fundamental insights into the tissue-specific function of VDR in modulating the balance between autophagy and apoptosis. [ABSTRACT FROM AUTHOR]

Background: Intestinal inflammation has various causes and leads to some inflammatory diseases, of which autophagy pathway dysfunction could be considered as one of them. Probiotics could have a positive effect on reducing inflammation by activating the autophagy pathway. To evaluate the precise effects of probiotics as preventive and therapeutic agents to control the symptoms of inflammatory diseases, we aimed to investigate the efficacy of Lactobacillus spp. in regulating the autophagy signaling pathway. Methods: A quantitative real‐time polymerase chain reaction assay was used to analyze the expression of autophagy genes involved in the formation of phagophores, autophagosomes, and autolysosomes after exposing the HT‐29 cell line to sonicated pathogens and adding Lactobacillus spp. before, after, and simultaneously with inflammation. A cytokine assay was also accomplished to evaluate the interleukin (IL)‐6 and IL‐1β level following the probiotic treatment. Results: Lactobacillus spp. generally increased autophagy gene expression and consumption of Lactobacillus spp. before, simultaneously, and after inflammation, ultimately leading to activate autophagy pathways. The proinflammatory cytokines including IL‐6 and IL‐1β decreased after probiotic treatment. Conclusions: Our native probiotic Lactobacillus spp. showed beneficial effects on HT‐29 cells by increasing autophagy gene expression and decreasing the proinflammatory cytokines production in all treatments. Therefore, this novel probiotic cocktail Lactobacillus spp. can prevent and treat inflammation‐related diseases. [ABSTRACT FROM AUTHOR]

Continuous exposure of intestinal mucosal surfaces to diverse microorganisms and their metabolites reflects the biological necessity for a multifaceted, integrated epithelial and immune cell-mediated regulatory system. The development and function of the host cells responsible for the barrier function of the intestinal surface (e.g., M cells, Paneth cells, goblet cells, and columnar epithelial cells) are strictly regulated through both positive and negative stimulation by the luminal microbiota. Stimulation by damage-associated molecular patterns and commensal bacteria-derived microbe-associated molecular patterns provokes the assembly of inflammasomes, which are involved in maintaining the integrity of the intestinal epithelium. Mucosal immune cells located beneath the epithelium play critical roles in regulating both the mucosal barrier and the relative composition of the luminal microbiota. Innate lymphoid cells and mast cells, in particular, orchestrate the mucosal regulatory system to create a mutually beneficial environment for both the host and the microbiota. Disruption of mucosal homeostasis causes intestinal inflammation such as that seen in inflammatory bowel disease. Here, we review the recent research on the biological interplay among the luminal microbiota, epithelial cells, and mucosal innate immune cells in both healthy and pathological conditions. [ABSTRACT FROM AUTHOR]

Bark protects the tree against environmental insults. Here, we analyzed whether this defensive strategy could be utilized to broadly enhance protection against colitis. As a proof of concept, we show that exosome‐like nanoparticles (MBELNs) derived from edible mulberry bark confer protection against colitis in a mouse model by promoting heat shock protein family A (Hsp70) member 8 (HSPA8)‐mediated activation of the AhR signaling pathway. Activation of this pathway in intestinal epithelial cells leads to the induction of COP9 Constitutive Photomorphogenic Homolog Subunit 8 (COPS8). Utilizing a gut epithelium‐specific knockout of COPS8, we demonstrate that COPS8 acts downstream of the AhR pathway and is required for the protective effect of MBELNs by inducing an array of anti‐microbial peptides. Our results indicate that MBELNs represent an undescribed mode of inter‐kingdom communication in the mammalian intestine through an AhR‐COPS8‐mediated anti‐inflammatory pathway. These data suggest that inflammatory pathways in a microbiota‐enriched intestinal environment are regulated by COPS8 and that edible plant‐derived ELNs may hold the potential as new agents for the prevention and treatment of gut‐related inflammatory disease. Synopsis: Mulberry bark derived exosome‐like nanoparticles (MBELNs) prevent gut inflammation via plant heat shock protein HSPA8‐mediated activation of AhR/COPS8 pathways. Treatment with MBELNs promotes the restoration of gut microbiome homeostasis, ameliorating intestinal inflammatory pathologies. Mulberry bark derived exosome‐like nanoparticles (MBELNs) prevent mouse colitis via the AhR/COPS8 pathway.Binding of MBELN‐derived heat shock protein HSPA8 to AhR leads to the activation of AhR signaling.Activation of AhR leads to the induction of an array of anti‐microbial peptides (AMPs) via COP9/COPS8.AhR/COPS8‐dependent induction of AMPs inhibits intestinal inflammation and alters fecal gut microbiota composition. [ABSTRACT FROM AUTHOR]

Aims Diversion colitis (DC) is a localized, relatively benign, iatrogenic condition which occurs in almost 100% of diverted colonic segments in patients who undergo ileostomy/colostomy for various reasons. The aim of this study was to establish histological features of DC in children. Methods and results Twenty-three cases of DC following colostomy for Hirschsprung's disease in young children were analysed. The distinguishing features included prominent follicular lymphoid hyperplasia (100%), chronic mucosal inflammation (100%), accompanied by a variable degree of acute inflammation (78%) and Paneth cell metaplasia (26%). Less frequent histological findings were as follows: mild goblet cell depletion (22%), foci of cryptitis (13%), crypt abscesses (13%) and mild architectural distortion (22%). A previously unrecognized feature was the presence of mucosal aggregates of eosinophils, found in 43% of cases. A striking similarity between the normal appearance of the vermiform appendix and pathological features in DC was noted and the possible relationship between the two is discussed. Conclusions Histological features of DC in children are very similar to those described in adults. They should help to distinguish it from ulcerative colitis and Hirschsprung's-associated enterocolitis in order to prevent inappropriate therapy and follow-up. There are many similarities between DC and the normal appendix vermiformis. [ABSTRACT FROM AUTHOR]

Bowel diseases reveal the complex interplay of sensing and signalling pathways in maintaining healthy homeostasis of the intestine. Recent studies of the xenobiotic nuclear receptor, pregnane X receptor and the inflammatory mediator nuclear transcription factor kappaB (NF-κB) reveal a functional link between xenobiotic neutralization and inflammation and explain how certain xenobiotics can affect the immune response. Furthermore, another nuclear receptor, peroxisome proliferator-activated receptor γ (PPARγ) has been shown to produce beneficial effects in experimental inflammatory bowel diseases by repression of NF-κB thereby reducing inflammation, whilst its close relative PPARβ/δ appears at a central position in signalling pathways involved in the progression of colon cancer. Recently accumulated knowledge on the action of these nuclear receptors and NF-κB in intestinal homeostasis may provide the rationale for the development of innovative treatment strategies with selective receptor modulators. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease causes a major burden to patients and healthcare systems, raising the need to develop effective therapies. Technological advances in cell culture, allied with ethical issues, have propelled in vitro models as essential tools to study disease aetiology, its progression, and possible therapies. Several cell‐based in vitro models of intestinal inflammation have been used, varying in their complexity and methodology to induce inflammation. Immortalized cell lines are extensively used due to their long‐term survival, in contrast to primary cultures that are short‐lived but patient‐specific. Recently, organoids and organ‐chips have demonstrated great potential by being physiologically more relevant. This review aims to shed light on the intricate nature of intestinal inflammation and cover recent works that report cell‐based in vitro models of human intestinal inflammation, encompassing diverse approaches and outcomes. [ABSTRACT FROM AUTHOR]

Summary: Obesity is characterized by chronic low‐grade inflammatory responses in the adipose tissue, accompanied by pronounced insulin resistance and metabolic anomalies. It affects almost all body organs and eventually leads to diseases such as fatty liver disease, type 2 diabetes mellitus, and atherosclerosis. Recently, T cells have emerged as interesting therapeutic targets because the dysfunction of T cells and their cytokines in the adipose tissue is implicated in obesity‐induced inflammation and their complicated onset. Although several recent narrative reviews have provided a brief overview of related evidence in this area, they have mainly focused on either obesity‐associated T cell metabolism or modulation of T cell activation in obesity. Moreover, at present, no published review has reported on the multifaceted roles of T cells in obesity and obesity‐related complications, even though there has been a significant increase in studies on this topic since 2019. Therefore, this narrative review aims to comprehensively summarize current advances in the mechanistic roles of T cells in the development of obesity and its related complications. Further, we aim to discuss relevant drugs for weight loss as well as the contradictory role of T cells in the same disease so as to highlight key findings regarding this topic and provide a valid basis for future treatment strategies. [ABSTRACT FROM AUTHOR]

Ulcerative colitis (UC) is an inflammatory bowel disorder (IBD) characterized by relapsing chronic inflammation of the colon that causes continuous mucosal inflammation. The global incidence of UC is steadily increasing. Immune mechanisms are involved in the pathogenesis of UC, of which complement is shown to play a critical role by inducing local chronic inflammatory responses that promote tissue damage. However, the function of various complement components in the development of UC is complex and even paradoxical. Some components (e.g. C1q, CD46, CD55, CD59, and C6) are shown to safeguard the intestinal barrier and reduce intestinal inflammation, while others (e.g. C3, C5, C5a) can exacerbate intestinal damage and accelerate the development of UC. The complement system was originally thought to function primarily in an extracellular mode; however, recent evidence indicates that it can also act intracellularly as the complosome. The current study provides an overview of current studies on complement and its role in the development of UC. While there are few studies that describe how intracellular complement contributes to UC, we discuss potential future directions based on related publications. We also highlight novel methods that target complement for IBD treatment. [ABSTRACT FROM AUTHOR]

The present project aimed to improve our understanding of potential effect of nanocellulose (NC) ingestion on human health, addressing some key objectives set by the European Food Safety Authority (EFSA). In particular, the use and improvement of not yet validated advanced in vitro models of human gut, both static and in tubular microfluidic format, was explored for assessing the interaction of the intestinal epithelium with nanocelluloses. NCs (nanofibers and nanocrystals) were examined as pristine material and upon exposure to digestive fluids and interaction with oro‐gastro‐intestinal enzymes. The NC local effects on the intestinal epithelium were assessed in terms of cytotoxicity, inflammation, and intestinal barrier integrity. Assessment of NC uptake and crossing of intestinal barrier was also explored. A specific focus was on immune reactivity at intestinal barrier site; the complex in vitro models were refined by complementation with primary innate immune cells. Exposure of intestinal tissues to inflammatory cytokines allowed to mimic the effect associated with disease condition and to address inflammation‐induced secondary toxicity. [ABSTRACT FROM AUTHOR]

The polymorphic microbiome has been proposed as a new hallmark of cancer. Intratumor microbiome has been revealed to play vital roles in regulating tumor initiation and progression, but the regulatory mechanisms have not been fully uncovered. In this review, we illustrated that similar to other components in the tumor microenvironment, the reside and composition of intratumor microbiome are regulated by tumor cells and the surrounding microenvironment. The intratumor hypoxic, immune suppressive, and highly permeable microenvironment may select certain microbiomes, and tumor cells may directly interact with microbiome via molecular binding or secretions. Conversely, the intratumor microbiomes plays vital roles in regulating tumor initiation and progression via regulating the mutational landscape, the function of genes in tumor cells and modulating the tumor microenvironment, including immunity, inflammation, angiogenesis, stem cell niche, etc. Moreover, intratumor microbiome is regulated by anti‐cancer therapies and actively influences therapy response, which could be a therapeutic target or engineered to be a therapy weapon in the clinic. This review highlights the intratumor microbiome as a vital component in the tumor microenvironment, uncovers potential mutual regulatory mechanisms between the tumor microenvironment and intratumor microbiome, and points out the ongoing research directions and drawbacks of the research area, which should broaden our view of microbiome and enlighten further investigation directions. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effects of plasma exchange on the biomolecular profiles and histology of ileum and colon tissues in young and aged Sprague–Dawley male rats. Fourier transform infrared (FTIR) spectroscopy, linear discriminant analysis and support vector machine (SVM) techniques were employed to analyse the lipid, protein, and nucleic acid indices in young and aged rats. Following the application of young plasma, aged rats demonstrated biomolecular profiles similar to those of their younger counterparts. Histopathological and immunohistochemical assessments showed that young plasma had a protective effect on the intestinal tissues of aged rats, increasing cell density and reducing inflammation. Additionally, the expression levels of key inflammatory mediators tumour necrosis factor‐alpha and cyclooxygenase‐2 significantly decreased after young plasma administration. These findings underscore the therapeutic potential of young plasma for mitigating age‐related changes and inflammation in the intestinal tract. They highlight the critical role of plasma composition in the ageing process and suggest the need for further research to explore how different regions of the intestines respond to plasma exchange. Such understanding could facilitate the development of innovative therapies targeting the gastrointestinal system, enhancing overall health during ageing. [ABSTRACT FROM AUTHOR]

Inflammation plays an important role in the initiation and progression of colorectal cancer (CRC) and leads to β‐catenin accumulation in colitis‐related CRC. However, the mechanism remains largely unknown. Here, pancreatic progenitor cell differentiation and proliferation factor (PPDPF) is found to be upregulated in CRC and significantly correlated with tumor‐node‐metastasis (TNM) stages and survival time. Knockout of PPDPF in the intestinal epithelium shortens crypts, decreases the number of stem cells, and inhibits the growth of organoids and the occurrence of azoxymethane (AOM)/dextran sodium sulfate (DSS)‐induced CRC. Mechanistically, PPDPF is found to interact with Casein kinase 1α (CK1α), thereby disrupting its binding to Axin, disassociating the β‐catenin destruction complex, decreasing the phosphorylation of β‐catenin, and activating the Wnt/β‐catenin pathway. Furthermore, interleukin 6 (IL6)/Janus kinase 2 (JAK2)‐mediated inflammatory signals lead to phosphorylation of PPDPF at Tyr16 and Tyr17, stabilizing the protein. In summary, this study demonstrates that PPDPF is a key molecule in CRC carcinogenesis and progression that connects inflammatory signals to the Wnt/β‐catenin signaling pathway, providing a potential novel therapeutic target. Synopsis: The pancreatic progenitor cell differentiation and proliferation factor PPDPF activates the Wnt/β‐catenin pathway and promotes colorectal cancer progression. PPDPF connects inflammatory signals to Wnt/β‐catenin signaling, providing a new therapeutic target for CRC. PPDPF is upregulated in colorectal cancer and its levels correlate with clinical pathology.PPDPF knockout disrupts the homeostasis of the intestinal epithelium.PPDPF activates the Wnt/β‐catenin pathway by binding to CK1α, promoting tumorigenesis of colorectal cancer.Inflammatory conditions promote PPDPF phosphorylation by JAK2, thereby preventing degradation of PPDPF by HUWE1. [ABSTRACT FROM AUTHOR]

Summary: Among the phospholipase A2 (PLA2) superfamily, which typically catalyzes the sn‐2 hydrolysis of phospholipids to yield fatty acids and lysophospholipids, the secreted PLA2 (sPLA2) family contains 11 isoforms in mammals. Individual sPLA2s have unique enzymatic specificity toward fatty acids and polar heads of phospholipid substrates and display distinct tissue/cellular distributions, suggesting their distinct physiological functions. Recent studies using knockout and/or transgenic mice for a full set of sPLA2s have revealed their roles in modulation of immunity and related disorders. Application of mass spectrometric lipidomics to these mice has enabled to identify target substrates and products of individual sPLA2s in given tissue microenvironments. sPLA2s hydrolyze not only phospholipids in the plasma membrane of activated, damaged or dying mammalian cells, but also extracellular phospholipids such as those in extracellular vesicles, microbe membranes, lipoproteins, surfactants, and dietary phospholipids, thereby exacerbating or ameliorating various diseases. The actions of sPLA2s are dependent on, or independent of, the generation of fatty acid‐ or lysophospholipid‐derived lipid mediators according to the pathophysiological contexts. In this review, we make an overview of our current understanding of the roles of individual sPLA2s in various immune responses and associated diseases. [ABSTRACT FROM AUTHOR]

Autophagy, a highly conserved cellular self‐degradation pathway, has emerged with novel roles in the realms of immunity and inflammation. Genome‐wide association studies have unveiled a correlation between genetic variations in autophagy‐related genes and heightened susceptibility to autoimmune and inflammatory diseases. Subsequently, substantial progress has been made in unraveling the intricate involvement of autophagy in immunity and inflammation through functional studies. The autophagy pathway plays a crucial role in both innate and adaptive immunity, encompassing various key functions such as pathogen clearance, antigen processing and presentation, cytokine production, and lymphocyte differentiation and survival. Recent research has identified novel approaches in which the autophagy pathway and its associated proteins modulate the immune response, including noncanonical autophagy. This review provides an overview of the latest advancements in understanding the regulation of immunity and inflammation through autophagy. It summarizes the genetic associations between variants in autophagy‐related genes and a range of autoimmune and inflammatory diseases, while also examining studies utilizing transgenic animal models to uncover the in vivo functions of autophagy. Furthermore, the review delves into the mechanisms by which autophagy dysregulation contributes to the development of three common autoimmune and inflammatory diseases and highlights the potential for autophagy‐targeted therapies. [ABSTRACT FROM AUTHOR]

Regulated cell death pathways have important functions in host defense and tissue homeostasis. Studies in genetic mouse models provided evidence that cell death could cause inflammation in different tissues. Inhibition of RIPK3- MLKL-dependent necroptosis by FADD and caspase-8 was identified as a key mechanism preventing inflammation in epithelial barriers. Moreover, the interplay between IKK/ NF-κB and RIPK1 signaling was recognized as a critical determinant of tissue homeostasis and inflammation. NEMO was shown to regulate RIPK1 kinase activity-mediated apoptosis by NF-κB-dependent and -independent functions, which are critical for averting chronic tissue injury and inflammation in the intestine and the liver. In addition, RIPK1 was shown to exhibit kinase activity-independent functions that are essential for preventing cell death, maintaining tissue architecture and inhibiting inflammation. In the intestine, RIPK1 acts as a scaffold to prevent epithelial cell apoptosis and preserve tissue integrity. In the skin, RIPK1 functions via its RHIM to counteract ZBP1/ DAI-dependent activation of RIPK3- MLKL-dependent necroptosis and inflammation. Collectively, these studies provided evidence that the regulation of cell death signaling plays an important role in the maintenance of tissue homeostasis, and suggested that cell death could be causally involved in the pathogenesis of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Lipids play a major role in inflammatory diseases by altering inflammatory cell functions, either through their function as energy substrates or as lipid mediators such as oxylipins. Autophagy, a lysosomal degradation pathway that limits inflammation, is known to impact on lipid availability, however, whether this controls inflammation remains unexplored. We found that upon intestinal inflammation visceral adipocytes upregulate autophagy and that adipocyte‐specific loss of the autophagy gene Atg7 exacerbates inflammation. While autophagy decreased lipolytic release of free fatty acids, loss of the major lipolytic enzyme Pnpla2/Atgl in adipocytes did not alter intestinal inflammation, ruling out free fatty acids as anti‐inflammatory energy substrates. Instead, Atg7‐deficient adipose tissues exhibited an oxylipin imbalance, driven through an NRF2‐mediated upregulation of Ephx1. This shift reduced secretion of IL‐10 from adipose tissues, which was dependent on the cytochrome P450‐EPHX pathway, and lowered circulating levels of IL‐10 to exacerbate intestinal inflammation. These results suggest an underappreciated fat‐gut crosstalk through an autophagy‐dependent regulation of anti‐inflammatory oxylipins via the cytochrome P450‐EPHX pathway, indicating a protective effect of adipose tissues for distant inflammation. Synopsis: Cell‐extrinsic effects of autophagy on inflammation remain poorly understood. This study identifies adipocyte autophagy as an important contributor to an adipose‐driven anti‐inflammatory response to intestinal inflammation. Adipocyte autophagy is induced by DSS‐induced colitis in mice and in Crohn's disease patients.Loss of autophagy in mature adipocytes results in an exacerbation of DSS‐induced intestinal inflammation.Augmented DSS‐induced intestinal inflammation upon adipocyte‐specific autophagy inhibition was not due to reduced adipose tissue lipolysis.Adipocyte‐specific autophagy loss resulted in altered oxylipin metabolism via activation of the cytochrome P450‐EPHX pathway.Oxylipin imbalance impaired IL‐10 secretion from adipose tissues of DSS‐treated mice. [ABSTRACT FROM AUTHOR]

Interleukin (IL)‐1β is a key innate cytokine that is essential for immune activation and promoting the inflammatory process. However, abnormal elevation in IL‐1β levels has been associated with unwanted clinical outcomes. IL‐1β is the most extensively studied cytokine among the IL‐1 family of cytokines and its role in pathology is well established. During the course of human immunodeficiency virus type 1 (HIV‐1) infection, the level of this proinflammatory cytokine is increased in different anatomical compartments, particularly in lymphatic tissues, and this elevation is associated with disease progression. The aim of this review is to address the pathological roles play by IL‐1β in the light of enhancing HIV‐1 replication, driving immune cell depletion, and chronic immune activation. The role of IL‐1β in HIV‐1 transmission (sexually or vertically 'from mother‐to‐child') will also be discussed. Additionally, the impact of the available antiretroviral therapy regimens on the levels of IL‐1β in HIV‐1 treated patients is also discussed. Finally, we will provide a glance on how IL‐1β could be targeted as a therapeutic strategy. [ABSTRACT FROM AUTHOR]

Exposure of mitochondrial DNA (mtDNA) to the cytosol activates innate immune responses. But the mechanisms by which mtDNA crosses the inner mitochondrial membrane are unknown. Here, we found that the inner mitochondrial membrane protein prohibitin 1 (PHB1) plays a critical role in mtDNA release by regulating permeability across the mitochondrial inner membrane. Loss of PHB1 results in alterations in mitochondrial integrity and function. PHB1‐deficient macrophages, serum from myeloid‐specific PHB1 KO (Phb1MyeKO) mice, and peripheral blood mononuclear cells from neonatal sepsis patients show increased interleukin‐1β (IL‐1β) levels. PHB1 KO mice are also intolerant of lipopolysaccharide shock. Phb1‐depleted macrophages show increased cytoplasmic release of mtDNA and inflammatory responses. This process is suppressed by cyclosporine A and VBIT‐4, which inhibit the mitochondrial permeability transition pore (mPTP) and VDAC oligomerization. Inflammatory stresses downregulate PHB1 expression levels in macrophages. Under normal physiological conditions, the inner mitochondrial membrane proteins, AFG3L2 and SPG7, are tethered to PHB1 to inhibit mPTP opening. Downregulation of PHB1 results in enhanced interaction between AFG3L2 and SPG7, mPTP opening, mtDNA release, and downstream inflammatory responses. Synopsis: The inner mitochondrial membrane protein Prohibitin 1 (PHB1) restrains mitochondrial DNA release and inflammation by binding to the mitochondrial membrane proteins AFG3L2 and SPG7. Inflammatory stresses enhance the interaction between AFG3L2 and SPG7, mPTP opening, mtDNA release and downstream inflammatory responses. Inflammatory stresses downregulate PHB1 levels in murine and human macrophages, which promotes inflammatory responses.PHB1 deficiency perturbs mitochondrial homeostasis, including increased mitochondrial permeability transition pore (mPTP) opening and mtDNA release.PHB1 regulates the formation of mPTP by modulating the interaction between the inner mitochondrial membrane proteins SPG7 and AFG3L2. [ABSTRACT FROM AUTHOR]

The NOD1/2‐RIPK2 is a key cytosolic signaling complex that activates NF‐κB pro‐inflammatory response against invading pathogens. However, uncontrolled NF‐κB signaling can cause tissue damage leading to chronic diseases. The mechanisms by which the NODs‐RIPK2‐NF‐κB innate immune axis is activated and resolved remain poorly understood. Here, we demonstrate that bacterial infection induces the formation of endogenous RIPK2 oligomers (RIPosomes) that are self‐assembling entities that coat the bacteria to induce NF‐κB response. Next, we show that autophagy proteins IRGM and p62/SQSTM1 physically interact with NOD1/2, RIPK2 and RIPosomes to promote their selective autophagy and limit NF‐κB activation. IRGM suppresses RIPK2‐dependent pro‐inflammatory programs induced by Shigella and Salmonella. Consistently, the therapeutic inhibition of RIPK2 ameliorates Shigella infection‐ and DSS‐induced gut inflammation in Irgm1 KO mice. This study identifies a unique mechanism where the innate immune proteins and autophagy machinery are recruited together to the bacteria for defense as well as for maintaining immune homeostasis. Synopsis: Bacterial infection induces the formation of RIPosomes (RIPK2 oligomers) that are recruited to the bacteria to enhance the NF‐κB response. To maintain innate immune homeostasis, RIPosomes undergo selective autophagy mediated by autophagy proteins, IRGM, and p62/SQSTM1. RIPosomes are self‐assembling structures that are formed upon bacterial infection and coat bacteria to induce NF‐κB response.IRGM‐ and p62‐mediated selective autophagy degrades NODs, RIPK2, and RIPosomes to suppress NF‐κB response.IRGM suppresses RIPK2‐dependent NF‐κB and interferon responses upon Shigella‐ and Salmonella infection.RIPK2 inhibition using GSK583 ameliorates shigellosis‐ and DSS‐induced gut inflammation in Irgm1KO mice [ABSTRACT FROM AUTHOR]

Aims: Several types of nonconventional dysplasia have been described in inflammatory bowel disease. Hypermucinous, goblet cell-deficient, and crypt cell dysplasias are considered high-risk subtypes, as they often have molecular features of advanced neoplasia (e.g. aneuploidy) and are more frequently associated with advanced neoplasia than conventional dysplasia. This study investigated if increased colonic inflammation is a risk factor for nonconventional dysplasia. Methods and Results: A cohort of 125 patients with ulcerative colitis (UC)-associated dysplasia were analyzed and compared with 50 control UC patients without a history of neoplasia. For each patient, all biopsies prior to the initial detection of dysplasia were scored using a 4-point inflammatory activity score. Both mean and maximum scores from all biopsies taken during each colonoscopy were derived. Inflammation burden was calculated by multiplying the average maximum score between each pair of surveillance episodes by length of surveillance interval in years. The average scores of all colonoscopies were used to calculate overall mean, maximum, and inflammation burden scores. In multivariate analyses, higher maximum (odds ratio [OR] 3.4) and inflammation burden (OR 4.2) scores were significantly associated with the detection of dysplasia (P < 0.05). Similarly, higher mean and maximum scores increased the odds of nonconventional dysplasia by 2.7 and 4.9, respectively (P < 0.05). There was a stronger association between these two scores and high-risk subtypes (ORs 4.0 and 7.5, respectively, P < 0.05). Conclusion: The risk of nonconventional dysplasia is significantly associated with increased colonic inflammation, which may contribute to its higher rates of aneuploidy and malignancy. [ABSTRACT FROM AUTHOR]

Polycystic ovarian syndrome (PCOS) is a complicated neuro‐endocrinal, reproductive, and metabolic condition. It encompasses patterns such as hyperandrogenism, recurrent cysts triggered by steroidogenic functional aberrations in the ovaries, overweight, chronic inflammation, and more. The underlying cause of this heterogeneous illness is obscure, although it is suspected to be driven by a blend of environmental and hereditary factors. In recent years, the connection between the microbiome and PCOS has been acknowledged and is thought to be involved in the genesis of the syndrome's emergence. Microbiota vary in different pathological features of PCOS, and fundamental pathways linked to their involvement in the commencement of diverse clinical presentations in PCOS open up a new avenue for its management. Prebiotic, probiotic, synbiotic, and fecal‐microbiota‐transplant, by promoting eubiosis and nullifying the effect caused by the altered microbial profile in PCOS women, can aid in management of diverse phenotypes associated with the syndrome. These microbiota‐mediated treatments improve PCOS women's metabolic, inflammatory, and hormonal profiles. However, more studies are needed to elucidate the mechanisms that drive this positive effect. [ABSTRACT FROM AUTHOR]

A commensal microbial community is established in the mammalian gut during its development, and these organisms protect the host against pathogenic invaders. The hallmark of noninvasive Salmonella gut infection is the induction of inflammation via effector proteins secreted by the type III secretion system, which modulate host responses to create a new niche in which the pathogen can overcome the colonization resistance imposed by the microbiota. Several studies have shown that endogenous microbes are important to control Salmonella infection by competing for resources. However, there is limited information about antimicrobial mechanisms used by commensals and pathogens during these in vivo disputes for niche control. This review aims to revisit the steps that Salmonella needs to overcome during gut colonization—before and after the induction of inflammation—to achieve an effective infection. We focus on a series of reported and hypothetical antagonistic interbacterial interactions in which both contact‐independent and contact‐dependent mechanisms might define the outcome of the infection. [ABSTRACT FROM AUTHOR]

Helicobacter pylori is a pathogen that colonizes the stomach and causes chronic gastritis. Helicobacter pylori can colonize deep inside gastric glands, triggering increased R‐spondin 3 (Rspo3) signaling. This causes an expansion of the "gland base module," which consists of self‐renewing stem cells and antimicrobial secretory cells and results in gland hyperplasia. The contribution of Rspo3 receptors Lgr4 and Lgr5 is not well explored. Here, we identified that Lgr4 regulates Lgr5 expression and is required for H. pylori‐induced hyperplasia and inflammation, while Lgr5 alone is not. Using conditional knockout mice, we reveal that R‐spondin signaling via Lgr4 drives proliferation of stem cells and also induces NF‐κB activity in the proliferative stem cells. Upon exposure to H. pylori, the Lgr4‐driven NF‐κB activation is responsible for the expansion of the gland base module and simultaneously enables chemokine expression in stem cells, resulting in gland hyperplasia and neutrophil recruitment. This demonstrates a connection between R‐spondin‐Lgr and NF‐κB signaling that links epithelial stem cell behavior and inflammatory responses to gland‐invading H. pylori. Synopsis: The R‐spondin 3–Lgr4 receptor pathway controls gastric gland‐invading pathogen by triggering epithelial expansion and release of pro‐inflammatory mediators. Conditional depletion of Lgr4 in the mouse stomach exhausts Lgr5 expression in the gland base and impairs gland response to Helicobacter pylori.Conditional depletion of Lgr5 alone does not affect epithelial homeostasis and responses to H. pylori.Rspo3 triggers epithelial self‐renewal and hyperplasia via Lgr4, increasing NF‐kappaB signaling‐dependent release of pro‐inflammatory cytokines in stem cells. [ABSTRACT FROM AUTHOR]

The innate immune system instructs the host on microbial exposure and infection. This information is critical to mount a protective innate and adaptive host response to microbial challenge, but is also involved in homeostatic and adaptive processes that adjust the organism to meet environmental requirements. This is of particular importance for the neonatal host during the transition from the protected fetal life to the intense and dynamic postnatal interaction with commensal and pathogenic microorganisms. Here, we discuss both adaptive and developmental mechanisms of the mucosal innate immune system that prevent inappropriate stimulation and facilitate establishment of a stable homeostatic host-microbial interaction after birth. [ABSTRACT FROM AUTHOR]

The intestine is the most densely colonized region of the body, inhabited by a diverse community of microbes. The functional significance of the intestinal microbiota is not yet fully understood, but it is known that the microbiota is implicated in numerous physiological processes of the host, such as metabolism, nutrition, the immune system, and regulation of behavior and mood. This article reviews recent findings on how bacteria of the intestinal microbiota interact with the host. Microbiota‐microbiota and microbiota‐host interactions are mediated by direct cell contact and by metabolites either produced by bacteria or produced by the host or the environment and metabolized by bacteria. Among them are short‐chain fatty, including butyrate, propionate, and acetate. Other examples include polyamines, linoleic acid metabolites, tryptophan metabolites, trimethylamine‐N‐oxide, vitamins, and secondary bile acids. These metabolites are involved in regulating the cell cycle, neurobiological signaling, cholesterol and bile acid metabolism, immune responses, and responses to antioxidants. Understanding the host‐microbiota pathways and their modulation will allow the identification of individualized therapeutic targets for many diseases. This overview helps to facilitate and promote further research in this field. [ABSTRACT FROM AUTHOR]

Defensin Alpha 4 (DEFA4) is the fourth member of the Alpha Defensins family known as a part of antimicrobial peptides in the innate immune system. DEFA4 has a strong preference to kill Gram-negative bacteria more than Gram-positive bacteria. In addition, DEFA4 exhibits antiviral activity against human immunodeficiency virus type 1 (HIV-1) in vitro. Moreover, DEFA4 can act as an inhibitor of corticosterone production (Corticostatin). On the other hand, alternations in DEFA4 gene expression have been reported in different disorders such as diseases related to inflammation and immunity dysfunction, brain-related disorders, and various cancers. The up-regulation of DEFA4 appears to be involved in the malignant transformation or aggressive form of cancer. Interestingly, the modified version of DEFA4 fragment (1–11) was potent and efficient against antibiotic-resistant bacteria. This review provides a general background abSaudi Arabia out DEFA4 and sheds light on changes in DEFA4 gene expression in different diseases. The paper also discusses other aspects related to DEFA4 as an antimicrobial and antiviral agent. The research was conducted based on available articles obtained from databases starting from 1988 to the present. [ABSTRACT FROM AUTHOR]

Aims: To review the literature on the histopathological diagnosis of the condition termed ‘autistic enterocolitis’. Methods and results: We have reviewed all published works where mucosal biopsy specimens from autistic children have been examined histopathologically. Abstracts were excluded. Our review of the published works, nearly all from a single centre, identifies major inconsistencies between studies, lack of appropriate controls and misinterpretation of normal findings as pathology. Ileal lymphoid hyperplasia may be more prevalent in children with regressive autism but is also seen in children with food allergies and severe constipation, the latter being an extremely common finding in autistic children. Conclusion: The histopathological diagnosis of autistic enterocolitis should be treated with caution until a proper study with appropriate methodology and controls is undertaken. [ABSTRACT FROM AUTHOR]

Vitamin D and its receptor are involved in health and diseases through multiple mechanisms including the immune system and gut microbiota modulations. Gut microbiota variations have huge implications in intestinal and extra‐intestinal disorders such as colorectal cancer (CRC). This review highlights the preventive role of vitamin D in colorectal tumorigenesis through the effects on the immune system and gut microbiota modulation. The different associations between vitamin D, gut microbial homeostasis, immune system, and CRC, are dissected. Vitamin D is supposed to exert several chemopreventive effects on CRC including direct antineoplastic mechanisms, the effects on the immune system, and gut microbiota modulation. Large clinical studies with a randomized design, are required to confirm the role of vitamin D in CRC, confirming its key role in the complex interplay between the gut immune system and microbiota. [ABSTRACT FROM AUTHOR]

Acute pancreatitis (AP) is an inflammatory gastrointestinal disorder affecting the pancreas. Previous study reported that tetraspanin 1 (TSPAN1) expression was significantly upregulated in the pancreas of AP patients. However, the underlying molecular mechanism of TSPAN1 in the pathogenesis of AP remains unclear. Thus, the aim of the present study was to investigate the potential role of TSPAN1 in development of AP. RT‐qPCR was carried out to quantify the relative mRNA levels of TSPAN1 and anterior gradient‐2 (AGR2). The CCK‐8 assay was used to detect the cell viability. The TUNEL assay was performed to visualize the apoptotic cells. Western blot was performed to determine the expressions of proteins related to endoplasmic reticulum (ER) stress and apoptosis. ELISA kits were adopted to detect the concentration of inflammatory cytokines including TNF‐α and IL‐6. Finally, immunoprecipitation (IP) was used to verify the interaction between TSPAN1 and AGR2. TSPAN1 was upregulated in serum of AP patients and AP cell models. TSPAN1 silencing promoted the cell proliferation and inhibited inflammatory response in cerulein‐induced AR42J cells. Moreover, TSPAN1 induced endoplasmic reticulum stress by binding AGR2. Interestingly, the overexpression of AGR2 abolished the effects of TSPAN1 silencing on cell proliferation and inflammatory response in cerulein‐induced AR42J cells. In summary, TSPAN1 silencing protects against cerulein‐induced pancreatic acinar cell injury through inhibiting ER stress‐mediated by AGR2. Hence, TSPAN1 may serve as a promising therapeutic target for AP treatment. [ABSTRACT FROM AUTHOR]

Inflammatory bowel diseases (IBDs) are a group of inflammatory conditions of the colon and small intestine, including Crohn's disease and ulcerative colitis. Since Danio rerio is a promising animal model to study gut function, we developed a soy‐dependent model of intestinal inflammation in adult zebrafish. The soya bean meal diet was given for 4 weeks and induced an inflammatory process, as demonstrated by morphological changes together with an increased percentage of neutrophils infiltrating the intestinal wall, which developed between the second and fourth week of treatment. Pro‐inflammatory genes such as interleukin‐1beta, interleukin‐8 and tumour necrosis factor alpha were upregulated in the second week and anti‐inflammatory genes such as transforming growth factor beta and interleukin‐10. Interestingly, an additional expression peak was found for interleukin‐8 at the fourth week. Neuronal genes, OTX1 and OTX2, were significantly upregulated in the first two weeks, compatible with the development of the changes in the gut wall. As for the genes of the p53 family such as p53, DNp63 and p73, a statistically significant increase was observed after two weeks of treatment compared with controls. Interestingly, DNp63 and p73 were shown an additional peak after four weeks. Our data demonstrate that soya bean meal diet negatively influences intestinal morphology and immunological function in adult zebrafish showing the features of acute inflammation. Data observed at the fourth week of treatment may suggest initiation of chronic inflammation. Adult zebrafish may represent a promising model to better understand the mechanisms of food‐dependent intestinal inflammation. [ABSTRACT FROM AUTHOR]

The therapeutic goal in inflammatory bowel disease (IBD) patients has shifted from controlling the clinical activity alone to managing other associated problems. The concept of mucosal healing (MH) and deep remission (DR) are advocated and regarded as new therapeutic goals in IBD. However, the definition of MH still remains controversial. It is unclear whether or not the histological structures or functional factors should be included in the definition of DR in addition to clinical remission and MH. The classifications of white‐light imaging (e.g. Mayo endoscopic subscore, UCEIS, CD Endoscopic Index of Severity, simple Endoscopic Score‐CD) have been proposed and are now widely used to assess the severity as well as the MH of inflammation in IBD. In ulcerative colitis, magnifying chromoendoscopy has been shown to be useful to assess the MH of inflammation while other types of image‐enhanced endoscopy, such as narrow‐band imaging, have not. Endocytoscopy and confocal laser endomicroscopy (CLE) are also applied to assess the activity in IBD. These endoscopic procedures can estimate MH with more precision through observing the details of superficial structures, such as crypt openings. In addition, CLE can partially assess the mucosal function by detecting fluorescence leakage. Molecular imaging can possibly detect the molecules associated with inflammation, intestinal regeneration and differentiation, and various functions including the intestinal barrier and mucus secretion. These novel procedures may improve the diagnosis strategy of DR through the assessment of DR‐associated factors such as the histological structures and functional factors in the near future. [ABSTRACT FROM AUTHOR]

Autophagy is a core molecular pathway for the preservation of cellular and organismal homeostasis. Pharmacological and genetic interventions impairing autophagy responses promote or aggravate disease in a plethora of experimental models. Consistently, mutations in autophagy‐related processes cause severe human pathologies. Here, we review and discuss preclinical data linking autophagy dysfunction to the pathogenesis of major human disorders including cancer as well as cardiovascular, neurodegenerative, metabolic, pulmonary, renal, infectious, musculoskeletal, and ocular disorders. [ABSTRACT FROM AUTHOR]

The intestinal microbiota influences mammalian host physiology in health and disease locally in the gut but also in organs devoid of direct contact with bacteria such as the liver and brain. Extracellular vesicles (EVs) or outer membrane vesicles (OMVs) released by microbes are increasingly recognized for their potential role as biological shuttle systems for inter‐kingdom communication. However, physiologically relevant evidence for the transfer of functional biomolecules from the intestinal microbiota to individual host cells by OMVs in vivo is scarce. By introducing Escherichia coli engineered to express Cre‐recombinase (E. coliCre) into mice with a Rosa26.tdTomato‐reporter background, we leveraged the Cre‐LoxP system to report the transfer of bacterial OMVs to recipient cells in vivo. Colonizing the intestine of these mice with E. coliCre, resulted in Cre‐recombinase induced fluorescent reporter gene‐expression in cells along the intestinal epithelium, including intestinal stem cells as well as mucosal immune cells such as macrophages. Furthermore, even far beyond the gut, bacterial‐derived Cre induced extended marker gene expression in a wide range of host tissues, including the heart, liver, kidney, spleen, and brain. Together, our findings provide a method and proof of principle that OMVs can serve as a biological shuttle system for the horizontal transfer of functional biomolecules between bacteria and mammalian host cells. [ABSTRACT FROM AUTHOR]

Aim: To explore the current literature on prenatal inflammation‐associated risk factors for retinopathy of prematurity (ROP). Methods: Subjective summary of selected experimental and epidemiological publications that support the authors' central hypothesis that the aetiology of ROP begins before birth. Results: Based on current evidence we suggest that, contrary to current aetiological models, the process of ROP development begins with a prephase in utero. This beginning is likely initiated by inflammatory responses that are associated with intrauterine infection. Conclusion: We propose a novel aetio‐pathogenetic model of ROP and suggest that the effects of postnatal exposure to inflammatory stressors (resulting from infection or hyperoxia or both) as well as those of other pre‐ and postnatal contributors to the complex pathogenesis of ROP might be modified by the prenatal phase of the disease. [ABSTRACT FROM AUTHOR]

The human microbiome is essential for the correct functioning of many host physiological processes, including metabolic regulation and immune responses. Increasing evidence indicates that the microbiome may also influence cancer development, progression, and the response to therapy. Although most studies have focused on the effect of the gut microbiome, many other organs such as the skin, vagina, and lungs harbor their own microbiomes that are different from the gut. Tumor development has been associated with dysbiosis not only in the gut but also in the tissue from which the tumor originated. Furthermore, the intratumoral microbiota has a distinct signature in each tumor type. Here, we review the mechanisms by which the organ-specific microbiome can contribute to carcinogenesis: release of toxins that cause DNA damage and barrier failure; alteration of immune responses to create a local inflammatory or immunosuppressive environment; and regulation of nutrient levels in the tumor microenvironment through metabolite production and consumption. Solving the puzzle of how the microbiome influences the carcinogenesis process and treatment response requires an understanding of the two ways the microbiome can interact with cancer cells and the tumor microenvironment: through systemic effects exerted by the gut microbiota and local effects of the intratumoral microbiota. [ABSTRACT FROM AUTHOR]