Intestinal commensal microbiota and cytokines regulate Fut2+ Paneth cells for gut defense

Paneth cells are intestinal epithelial cells that release antimicrobial peptides, such as α-defensin as part of host defense. Together with mesenchymal cells, Paneth cells provide niche factors for epithelial stem cell homeostasis. Here, we report two subtypes of murine Paneth cells, differentiated by their production and utilization of fucosyltransferase 2 (Fut2), which regulates α(1,2)fucosylation to create cohabitation niches for commensal bacteria and prevent invasion of the intestine by pathogenic bacteria. The majority of Fut2− Paneth cells were localized in the duodenum, whereas the majority of Fut2+ Paneth cells were in the ileum. Fut2+ Paneth cells showed higher granularity and structural complexity than did Fut2− Paneth cells, suggesting that Fut2+ Paneth cells are involved in host defense. Signaling by the commensal bacteria, together with interleukin 22 (IL-22), induced the development of Fut2+ Paneth cells. IL-22 was found to affect the α-defensin secretion system via modulation of Fut2 expression, and IL-17a was found to increase the production of α-defensin in the intestinal tract. Thus, these intestinal cytokines regulate the development and function of Fut2+ Paneth cells as part of gut defense.

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Beta-Defensin-2 and Beta-Defensin-3 Reduce Intestinal Damage Caused bySalmonella typhimuriumModulating the Expression of Cytokines and Enhancing the Probiotic Activity ofEnterococcus faecium

Journal of Immunology Research ◽

10.1155/2017/6976935 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 16

Author(s):

Alessandra Fusco ◽

Vittoria Savio ◽

Marcella Cammarota ◽

Alberto Alfano ◽

Chiara Schiraldi ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Intestinal Tract ◽

Intestinal Wall ◽

Intestinal Damage ◽

Intestinal Epithelial ◽

Intestinal Colonization ◽

Gene Encoding ◽

Key Factor ◽

Health And Disease ◽

Probiotic Activity

The intestinal microbiota is a major factor in human health and disease. This microbial community includes autochthonous (permanent inhabitants) and allochthonous (transient inhabitants) microorganisms that contribute to maintaining the integrity of the intestinal wall, modulating responses to pathogenic noxae and representing a key factor in the maturation of the immune system. If this healthy microbiota is disrupted by antibiotics, chemotherapy, or a change in diet, intestinal colonization by pathogenic bacteria or viruses may occur, leading to disease. To manage substantial microbial exposure, epithelial surfaces of the intestinal tract produce a diverse arsenal of antimicrobial peptides (AMPs), including, of considerable importance, theβ-defensins, which directly kill or inhibit the growth of microorganisms. Based on the literature data, the purpose of this work was to create a line of intestinal epithelial cells able to stably express gene encoding humanβ-defensin-2 (hBD-2) and humanβ-defensin-3 (hBD-3), in order to test their role inS. typhimuriuminfections and their interaction with the bacteria of the gut microbiota.

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Diverse Mechanisms Underlie Enhancement of Enteric Viruses by the Mammalian Intestinal Microbiota

Viruses ◽

10.3390/v11080760 ◽

2019 ◽

Vol 11 (8) ◽

pp. 760 ◽

Cited By ~ 5

Author(s):

Alexa N. Roth ◽

Katrina R. Grau ◽

Stephanie M. Karst

Keyword(s):

Intestinal Microbiota ◽

Pathogenic Bacteria ◽

Enteric Viruses ◽

Enteric Virus ◽

Commensal Bacteria ◽

Virus Infections ◽

Virus Binding ◽

Host Immune Responses ◽

And Function ◽

The Impact

Over the past two decades, there has been tremendous progress in understanding the impact of the intestinal microbiota on mammalian metabolism, physiology, and immune development and function. There has also been substantial advancement in elucidating the interplay between commensal and pathogenic bacteria. Relatively more recently, researchers have begun to investigate the effect of the intestinal microbiota on viral pathogenesis. Indeed, a growing body of literature has reported that commensal bacteria within the mammalian intestinal tract enhance enteric virus infections through a variety of mechanisms. Commensal bacteria or bacterial glycans can increase the stability of enteric viruses, enhance virus binding to host receptors, modulate host immune responses in a proviral manner, expand the numbers of host cell targets, and facilitate viral recombination. In this review, we will summarize the current literature exploring these effects of the intestinal microbiota on enteric virus infections.

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Entamoeba histolyticaAlters Ileal Paneth Cell Functions in Intact and Muc2 Mucin Deficiency

Infection and Immunity ◽

10.1128/iai.00208-18 ◽

2018 ◽

Vol 86 (7) ◽

pp. e00208-18 ◽

Cited By ~ 1

Author(s):

Eduardo R. Cobo ◽

Ravi Holani ◽

France Moreau ◽

Kiminori Nakamura ◽

Tokiyoshi Ayabe ◽

...

Keyword(s):

Entamoeba Histolytica ◽

Host Defense ◽

Cysteine Proteinase ◽

Paneth Cell ◽

Active Form ◽

Paneth Cells ◽

Content Type ◽

Cell Functions ◽

Pathogen Invasion ◽

And Function

ABSTRACTEnteric α-defensins, termed cryptdins (Crps) in mice, and lysozymes secreted by Paneth cells contribute to innate host defense in the ileum. Antimicrobial factors, including lysozymes and β-defensins, are often embedded in luminal glycosylated colonic Muc2 mucin secreted by goblet cells that form the protective mucus layer critical for gut homeostasis and pathogen invasion. In this study, we investigated ileal innate immunity againstEntamoeba histolytica, the causative agent of intestinal amebiasis, by inoculating parasites in closed ileal loops inMuc2+/+andMuc2−/−littermates and quantifying Paneth cell localization (lysozyme expression) and function (Crp secretion). Relative toMuc2+/+littermates,Muc2−/−littermates showed a disorganized mislocalization of Paneth cells that was diffusely distributed, with elevated lysozyme secretion in the crypts and on villi in response toE. histolytica. Inhibition ofE. histolyticaGal/GalNAc lectin (Gal-lectin) binding with exogenous galactose andEntamoeba histolyticacysteine proteinase 5 (EhCP5)-negativeE. histolyticahad no effect on parasite-induced erratic Paneth cell lysozyme synthesis. Although the basal ileal expression ofCrpgenes was unaffected inMuc2−/−mice in response toE. histolytica, there was a robust release of proinflammatory cytokines and Crp peptide secretions in luminal exudates that was also present in the colon. Interestingly,E. histolytica-secreted cysteine proteinases cleaved the proregion of Crp4 but not the active form. These findings define Muc2 mucin as an essential component of ileal barrier function that regulates the localization and function of Paneth cells critical for host defense against microbes.

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Proteomic analysis of the enterocyte brush border

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00005.2011 ◽

2011 ◽

Vol 300 (5) ◽

pp. G914-G926 ◽

Cited By ~ 49

Author(s):

Russell E. McConnell ◽

Andrew E. Benesh ◽

Suli Mao ◽

David L. Tabb ◽

Matthew J. Tyska

Keyword(s):

Brush Border ◽

Intestinal Tract ◽

Molecular Mechanisms ◽

Actin Dynamics ◽

Intestinal Epithelial ◽

Future Studies ◽

Nutrient Processing ◽

Shotgun Mass Spectrometry ◽

Membrane Bending ◽

And Function

The brush border domain at the apex of intestinal epithelial cells is the primary site of nutrient absorption in the intestinal tract and the primary surface of interaction with microbes that reside in the lumen. Because the brush border is positioned at such a critical physiological interface, we set out to create a comprehensive list of the proteins that reside in this domain using shotgun mass spectrometry. The resulting proteome contains 646 proteins with diverse functions. In addition to the expected collection of nutrient processing and transport components, we also identified molecules expected to function in the regulation of actin dynamics, membrane bending, and extracellular adhesion. These results provide a foundation for future studies aimed at defining the molecular mechanisms underpinning brush border assembly and function.

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Rules of Engagement: Epithelial-Microbe Interactions and Inflammatory Bowel Disease

Frontiers in Medicine ◽

10.3389/fmed.2021.669913 ◽

2021 ◽

Vol 8 ◽

Author(s):

Albert E. Jergens ◽

Shadi Parvinroo ◽

Jamie Kopper ◽

Michael J. Wannemuehler

Keyword(s):

Pathogenic Bacteria ◽

Intestinal Inflammation ◽

Disease Onset ◽

Intestinal Epithelial ◽

Bowel Diseases ◽

Exact Etiology ◽

Mucosal Homeostasis ◽

Inflammatory Bowel ◽

And Function ◽

Iga Production

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are complex, multifactorial disorders that lead to chronic and relapsing intestinal inflammation. The exact etiology remains unknown, however multiple factors including the environment, genetic, dietary, mucosal immunity, and altered microbiome structure and function play important roles in disease onset and progression. Supporting this notion that the gut microbiota plays a pivotal role in IBD pathogenesis, studies in gnotobiotic mice have shown that mouse models of intestinal inflammation require a microbial community to develop colitis. Additionally, antimicrobial therapy in some IBD patients will temporarily induce remission further demonstrating an association between gut microbes and intestinal inflammation. Finally, a dysfunctional intestinal epithelial barrier is also recognized as a key pathogenic factor in IBD. The intestinal epithelium serves as a barrier between the luminal environment and the mucosal immune system and guards against harmful molecules and microorganisms while being permeable to essential nutrients and solutes. Beneficial (i.e., mutualists) bacteria promote mucosal health by strengthening barrier integrity, increasing local defenses (mucin and IgA production) and inhibiting pro-inflammatory immune responses and apoptosis to promote mucosal homeostasis. In contrast, pathogenic bacteria and pathobionts suppress expression and localization of tight junction proteins, cause dysregulation of apoptosis/proliferation and increase pro-inflammatory signaling that directly damages the intestinal mucosa. This review article will focus on the role of intestinal epithelial cells (IECs) and the luminal environment acting as mediators of barrier function in IBD. We will also share some of our translational observations of interactions between IECs, immune cells, and environmental factors contributing to maintenance of mucosal homeostasis, as it relates to GI inflammation and IBD in different animal models.

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Nod2 is required for the regulation of commensal microbiota in the intestine

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0907722106 ◽

2009 ◽

Vol 106 (37) ◽

pp. 15813-15818 ◽

Cited By ~ 375

Author(s):

Tanja Petnicki-Ocwieja ◽

Tomas Hrncir ◽

Yuen-Joyce Liu ◽

Amlan Biswas ◽

Tomas Hudcovic ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Bacterial Flora ◽

Intestinal Bacteria ◽

Feedback Mechanism ◽

Commensal Bacteria ◽

Germ Free ◽

Commensal Microbiota ◽

Mucosal Homeostasis ◽

Deficient Mice

Mutations in the Nod2 gene are among the strongest genetic risk factors in the pathogenesis of ileal Crohn's disease, but the exact contributions of Nod2 to intestinal mucosal homeostasis are not understood. Here we show that Nod2 plays an essential role in controlling commensal bacterial flora in the intestine. Analysis of intestinal bacteria from the terminal ilea of Nod2-deficient mice showed that they harbor an increased load of commensal resident bacteria. Furthermore, Nod2-deficient mice had a diminished ability to prevent intestinal colonization of pathogenic bacteria. In vitro, intestinal crypts isolated from terminal ilea of Nod2-deficient mice were unable to kill bacteria effectively, suggesting an important role of Nod2 signaling in crypt function. Interestingly, the expression of Nod2 is dependent on the presence of commensal bacteria, because mice re-derived into germ-free conditions expressed significantly less Nod2 in their terminal ilea, and complementation of commensal bacteria into germ-free mice induced Nod2 expression. Therefore, Nod2 and intestinal commensal bacterial flora maintain a balance by regulating each other through a feedback mechanism. Dysfunction of Nod2 results in a break-down of this homeostasis.

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IL-22 receptor signaling in Paneth cells is critical for their maturation, microbiota colonization, Th17-related immune responses, and anti-Salmonella immunity

Mucosal Immunology ◽

10.1038/s41385-020-00348-5 ◽

2020 ◽

Author(s):

Stephen J. Gaudino ◽

Michael Beaupre ◽

Xun Lin ◽

Preet Joshi ◽

Sonika Rathi ◽

...

Keyword(s):

Immune Responses ◽

Host Defense ◽

Knockout Mice ◽

Paneth Cell ◽

Cell Types ◽

Paneth Cells ◽

Lineage Tracing ◽

Interleukin 22 ◽

Serovar Typhimurium ◽

Small Intestinal

Abstract Interleukin-22 (IL-22) signaling in the intestines is critical for promoting tissue-protective functions. However, since a diverse array of cell types (absorptive and secretory epithelium as well as stem cells) express IL-22Ra1, a receptor for IL-22, it has been difficult to determine what cell type(s) specifically respond to IL-22 to mediate intestinal mucosal host defense. Here, we report that IL-22 signaling in the small intestine is positively correlated with Paneth cell differentiation programs. Our Il22Ra1fl/fl;Lgr5-EGFP-creERT2-specific knockout mice and, independently, our lineage-tracing findings rule out the involvement of Lgr5+ intestinal stem cell (ISC)-dependent IL-22Ra1 signaling in regulating the lineage commitment of epithelial cells, including Paneth cells. Using novel Paneth cell-specific IL-22Ra1 knockout mice (Il22Ra1fl/fl;Defa6-cre), we show that IL-22 signaling in Paneth cells is required for small intestinal host defense. We show that Paneth cell maturation, antimicrobial effector function, expression of specific WNTs, and organoid morphogenesis are dependent on cell-intrinsic IL-22Ra1 signaling. Furthermore, IL-22 signaling in Paneth cells regulates the intestinal commensal bacteria and microbiota-dependent IL-17A immune responses. Finally, we show ISC and, independently, Paneth cell-specific IL-22Ra1 signaling are critical for providing immunity against Salmonella enterica serovar Typhimurium. Collectively, our findings illustrate a previously unknown role of IL-22 in Paneth cell-mediated small intestinal host defense.

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Search for Compounds Suppressing Intestinal α-Glucosidase Expression in Caco-2 Cells

ICONIET PROCEEDING ◽

10.33555/iconiet.v2i2.18 ◽

2019 ◽

Vol 2 (2) ◽

pp. 96-101

Author(s):

Kota Noda ◽

Eisuke Kato ◽

Jun Kawabata

Keyword(s):

Blood Glucose ◽

Intestinal Tract ◽

Cell Model ◽

Epigallocatechin Gallate ◽

Calluna Vulgaris ◽

Active Principle ◽

Intestinal Epithelial ◽

Mrna Expression Level ◽

Epicatechin Gallate ◽

Control Post

Diabetes is a chronic disease characterized by elevated blood glucose level.Reducing carbohydrate absorption from the intestinal tract is an effective strategy to control post-meal blood glucose level. Inhibition of intestinal α-glucosidase, involved in digestion of carbohydrates, is known as an approach to accomplish this. On the other hand, reduction of α-glucosidase amount is expected to work in the similar manner. However, none of the previousstudy pursues this approach. A convenient assay was developed to evaluate α-glucosidase amount employing Caco-2 cells, the intestinal epithelial cell model reported to express α-glucosidase. Sixty plants were screened and two candidate plants, Calluna vulgaris and Perilla frutescens var. crispa were found to reduce α-glucosidase expression. C. vulgaris extract was subjected to activity guided isolation. Proanthocyanidin was identified as the active principle which was analyzed by thiol decomposition to reveal the components as a mixture ofcatechin, epicatechin, epigallocatechin, and A type procyanidin dimer. The proanthocyanidin suppressed about 30% of α-glucosidase amount evaluated through convenient assay, and suppressed bulk of mRNA expression level of sucrase-isomaltase (SI) at 0.125 mg/mL. Several flavan-3-ol monomers were also tested, and epicatechin gallate and epigallocatechin gallate were found to suppress α-glucosidase amount significantly.

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