Microarray analysis of differentially expressed transcripts in porcine intestinal epithelial cells (IPEC-J2) infected with porcine sapelovirus as a model to study innate immune responses to enteric viruses

ABSTRACT Enterohepatic Helicobacter species infect the intestinal tracts and biliary trees of various mammals, including mice and humans, and are associated with chronic inflammatory diseases of the intestine, gallstone formation, and malignant transformation. The recent analysis of the whole genome sequence of the mouse enterohepatic species Helicobacter hepaticus allowed us to perform a functional analysis of bacterial factors that may play a role in these diseases. We tested the hypothesis that H. hepaticus suppresses or evades innate immune responses of mouse intestinal epithelial cells, which allows this pathogen to induce or contribute to chronic inflammatory disease. We demonstrated in the present study that the innate immune responses of intestinal epithelial cells to lipopolysaccharide (LPS) via Toll-like receptor 4 (TLR4) and to flagellin-mediated activation via TLR5 are reduced by H. hepaticus infection through soluble bacterial factors. In particular, H. hepaticus lysate and the soluble component LPS antagonized TLR4- and TLR5-mediated immune responses of intestinal epithelial cells. H. hepaticus lysate and LPS inhibited development of endotoxin tolerance to Escherichia coli LPS. Suppression of innate immune responses by H. hepaticus LPS thus may affect intestinal responses to the resident microbial flora, epithelial homeostasis, and intestinal inflammatory conditions.

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A30 DIFFERENCES BETWEEN HUMAN AND MOUSE INTESTINAL EPITHELIAL CELLS IN THEIR INNATE IMMUNE RESPONSES TO BACTERIAL AND HOST STIMULI.

Journal of the Canadian Association of Gastroenterology ◽

10.1093/jcag/gwab002.029 ◽

2021 ◽

Vol 4 (Supplement_1) ◽

pp. 2-3

Author(s):

J M Allaire ◽

A Poon ◽

S M Crowley ◽

X Han ◽

M Stahl ◽

...

Keyword(s):

Epithelial Cells ◽

Immune Responses ◽

Inflammatory Responses ◽

Intestinal Epithelial Cells ◽

Innate Immune ◽

Negative Regulator ◽

Intestinal Epithelial ◽

Innate Immune Responses ◽

Transformed Cell Lines ◽

First Time

Abstract Background Intestinal epithelial cells (IEC) reside in close contact with the gut microbiota. It is thus important that IEC are hypo-responsive to bacterial products to prevent maladaptive inflammatory responses in the gut, such as those seen in Inflammatory bowel diseases (IBD). This suppression of innate immune signaling in IEC is in part due to their strong expression of Single Ig IL1 related receptor (SIGIRR), a negative regulator of interleukin (IL)-1 and toll-like receptor (TLR) signaling. IL37, a newly recognized anti-inflammatory cytokine has been shown to strongly inhibit innate signaling in cells by binding to, and signaling through SIGIRR, leading to suppression of various forms of inflammation in mice. Few studies have looked at the function of IL-37/SIGIRR in IEC and their potential use to balance inflammatory responses. Notably, while many groups have studied IEC immune response in vitro, using transformed IEC lines, our focus is on primary-derived IEC which more accurately reflect in vivo responses. Aims To characterize IEC intrinsic and species-specific immune responses elicited by bacteria and host products as well as the role of IL37/SIGIRR in regulating this innate signaling. Methods We used organoid to study the innate immune responses of primary IEC derived from human or mouse colon (colonoids). After stimulation with inflammatory stimuli (IL1β, FliC and LPS), qPCR, ELISA, Milliplex Multiplex Assay and Western blot were used to determine modification in signalling pathway and cytokine/chemokine secretion. Results Using colonoids derived from healthy donors, we demonstrated that unlike transformed cell lines or mouse IEC, human IEC respond only to the bacterial product FliC, and not to LPS or IL1β. We further characterized human colonoid innate immune responses and despite significant inter-individual variability upon FliC stimulation, all organoids released several chemokines (IL8, CXCL1, CXCL2, CCL2 and CCL20). We showed for the first time that IL37 attenuated these innate immune responses through inhibition of intracellular signaling pathways (p38 and NFkB). Using colonoids derived from wildtype and Sigirr deficient mice, we found that mice IEC were responsive to IL1b and FliC and that the suppressive effects of IL37 were Sigirr dependent. Conclusions Our results show that human IEC show variability among individuals in the magnitude of their innate immune responses, and these responses differ from those obtained from transformed cells and primary mouse IEC. For the first time, we show that IL37 suppresses IEC innate immune responses, through its ability to signal through Sigirr. Further investigations will assess the ability of IL37 to control inflammation of IEC derived from IBD patients, as a potential therapeutic to promote gut health. Funding Agencies CAG, CIHRMSFHR

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The Bacterial Species Campylobacter jejuni Induce Diverse Innate Immune Responses in Human and Avian Intestinal Epithelial Cells

Frontiers in Microbiology ◽

10.3389/fmicb.2017.01840 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 8

Author(s):

Daniel A. John ◽

Lisa K. Williams ◽

Venkateswarlu Kanamarlapudi ◽

Thomas J. Humphrey ◽

Thomas S. Wilkinson

Keyword(s):

Epithelial Cells ◽

Immune Responses ◽

Campylobacter Jejuni ◽

Intestinal Epithelial Cells ◽

Bacterial Species ◽

Innate Immune ◽

Intestinal Epithelial ◽

Innate Immune Responses

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Ligilactobacillus salivarius Strains Isolated From the Porcine Gut Modulate Innate Immune Responses in Epithelial Cells and Improve Protection Against Intestinal Viral-Bacterial Superinfection

Frontiers in Immunology ◽

10.3389/fimmu.2021.652923 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yuhki Indo ◽

Shugo Kitahara ◽

Mikado Tomokiyo ◽

Shota Araki ◽

Md. Aminul Islam ◽

...

Keyword(s):

Immune Response ◽

Epithelial Cells ◽

Immune Responses ◽

Innate Immune ◽

Intestinal Epithelial ◽

Innate Immune Responses ◽

Rotavirus Infection ◽

Intestinal Infections ◽

Immune Health

Previously, we constructed a library of Ligilactobacillus salivarius strains from the intestine of wakame-fed pigs and reported a strain-dependent capacity to modulate IFN-β expression in porcine intestinal epithelial (PIE) cells. In this work, we further characterized the immunomodulatory activities of L. salivarius strains from wakame-fed pigs by evaluating their ability to modulate TLR3- and TLR4-mediated innate immune responses in PIE cells. Two strains with a remarkable immunomodulatory potential were selected: L. salivarius FFIG35 and FFIG58. Both strains improved IFN-β, IFN-λ and antiviral factors expression in PIE cells after TLR3 activation, which correlated with an enhanced resistance to rotavirus infection. Moreover, a model of enterotoxigenic E. coli (ETEC)/rotavirus superinfection in PIE cells was developed. Cells were more susceptible to rotavirus infection when the challenge occurred in conjunction with ETEC compared to the virus alone. However, L. salivarius FFIG35 and FFIG58 maintained their ability to enhance IFN-β, IFN-λ and antiviral factors expression in PIE cells, and to reduce rotavirus replication in the context of superinfection. We also demonstrated that FFIG35 and FFIG58 strains regulated the immune response of PIE cells to rotavirus challenge or ETEC/rotavirus superinfection through the modulation of negative regulators of the TLR signaling pathway. In vivo studies performed in mice models confirmed the ability of L. salivarius FFIG58 to beneficially modulate the innate immune response and protect against ETEC infection. The results of this work contribute to the understanding of beneficial lactobacilli interactions with epithelial cells and allow us to hypothesize that the FFIG35 or FFIG58 strains could be used for the development of highly efficient functional feed to improve immune health status and reduce the severity of intestinal infections and superinfections in weaned piglets.

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Luminal-Applied Flagellin Is Internalized by Polarized Intestinal Epithelial Cells and Elicits Immune Responses via the TLR5 Dependent Mechanism

PLoS ONE ◽

10.1371/journal.pone.0024869 ◽

2011 ◽

Vol 6 (9) ◽

pp. e24869 ◽

Cited By ~ 10

Author(s):

Tonyia Eaves-Pyles ◽

Heng-Fu Bu ◽

Xiao-di Tan ◽

Yingzi Cong ◽

Jignesh Patel ◽

...

Keyword(s):

Epithelial Cells ◽

Immune Responses ◽

Intestinal Epithelial Cells ◽

Intestinal Epithelial ◽

Dependent Mechanism

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Intrinsic pollen NADPH oxidases induce genes by activating innate immune responses in human bronchial epithelial cells*1

Journal of Allergy and Clinical Immunology ◽

10.1016/j.jaci.2004.01.694 ◽

2004 ◽

Vol 113 (2) ◽

pp. S330

Author(s):

R BLOEBAUM

Keyword(s):

Epithelial Cells ◽

Immune Responses ◽

Bronchial Epithelial Cells ◽

Innate Immune ◽

Innate Immune Responses ◽

Human Bronchial Epithelial Cells ◽

Nadph Oxidases ◽

Bronchial Epithelial

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Herpes Simplex Virus 1 Infection of Neuronal and Non-Neuronal Cells Elicits Specific Innate Immune Responses and Immune Evasion Mechanisms

Frontiers in Immunology ◽

10.3389/fimmu.2021.644664 ◽

2021 ◽

Vol 12 ◽

Author(s):

Amanda L. Verzosa ◽

Lea A. McGeever ◽

Shun-Je Bhark ◽

Tracie Delgado ◽

Nicole Salazar ◽

...

Keyword(s):

Herpes Simplex ◽

Epithelial Cells ◽

Immune Responses ◽

Host Cell ◽

Signaling Pathways ◽

Sensory Neurons ◽

Immune Evasion ◽

Innate Immune ◽

Innate Immune Responses ◽

Hsv 1

Alphaherpesviruses (α-HV) are a large family of double-stranded DNA viruses which cause many human and animal diseases. There are three human α-HVs: Herpes Simplex Viruses (HSV-1 and HSV-2) and Varicella Zoster Virus (VZV). All α-HV have evolved multiple strategies to suppress or exploit host cell innate immune signaling pathways to aid in their infections. All α-HVs initially infect epithelial cells (primary site of infection), and later spread to infect innervating sensory neurons. As with all herpesviruses, α-HVs have both a lytic (productive) and latent (dormant) stage of infection. During the lytic stage, the virus rapidly replicates in epithelial cells before it is cleared by the immune system. In contrast, latent infection in host neurons is a life-long infection. Upon infection of mucosal epithelial cells, herpesviruses immediately employ a variety of cellular mechanisms to evade host detection during active replication. Next, infectious viral progeny bud from infected cells and fuse to neuronal axonal terminals. Here, the nucleocapsid is transported via sensory neuron axons to the ganglion cell body, where latency is established until viral reactivation. This review will primarily focus on how HSV-1 induces various innate immune responses, including host cell recognition of viral constituents by pattern-recognition receptors (PRRs), induction of IFN-mediated immune responses involving toll-like receptor (TLR) signaling pathways, and cyclic GMP‐AMP synthase stimulator of interferon genes (cGAS-STING). This review focuses on these pathways along with other mechanisms including autophagy and the complement system. We will summarize and discuss recent evidence which has revealed how HSV-1 is able to manipulate and evade host antiviral innate immune responses both in neuronal (sensory neurons of the trigeminal ganglia) and non-neuronal (epithelial) cells. Understanding the innate immune response mechanisms triggered by HSV-1 infection, and the mechanisms of innate immune evasion, will impact the development of future therapeutic treatments.

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Long Non-coding RNAs RN7SK and GAS5 Regulate Macrophage Polarization and Innate Immune Responses

Frontiers in Immunology ◽

10.3389/fimmu.2020.604981 ◽

2020 ◽

Vol 11 ◽

Author(s):

Imran Ahmad ◽

Araceli Valverde ◽

Raza Ali Naqvi ◽

Afsar R. Naqvi

Keyword(s):

Immune Responses ◽

Epigenetic Regulation ◽

Innate Immune ◽

Differentially Expressed ◽

Immune Functions ◽

Innate Immune Responses ◽

Antigen Uptake ◽

Non Coding Rnas

Macrophages (Mφ) are immune cells that exhibit remarkable functional plasticity. Identification of novel endogenous factors that can regulate plasticity and innate immune functions of Mφ will unravel new strategies to curb immune-related diseases. Long non-coding RNAs (lncRNAs) are a class of endogenous, non-protein coding, regulatory RNAs that are increasingly being associated with various cellular functions and diseases. Despite their ubiquity and abundance, lncRNA-mediated epigenetic regulation of Mφ polarization and innate immune functions is poorly studied. This study elucidates the regulatory role of lncRNAs in monocyte to Mφ differentiation, M1/M2 dichotomy and innate immune responses. Expression profiling of eighty-eight lncRNAs in monocytes and in vitro differentiated M2 Mφ identified seventeen differentially expressed lncRNAs. Based on fold-change and significance, we selected four differentially expressed lncRNAs viz., RN7SK, GAS5, IPW, and ZFAS1 to evaluate their functional impact. LncRNA knockdown was performed on day 3 M2 Mφ and the impact on polarization was assessed on day 7 by surface marker analysis. Knockdown of RN7SK and GAS5 showed downregulation of M2 surface markers (CD163, CD206, or Dectin) and concomitant increase in M1 markers (MHC II or CD23). RN7SK or GAS5 knockdown showed no significant impact on CD163, CD206, or CD23 transcripts. M1/M2 markers were not impacted by IPW or ZFAS1 knockdown. Functional regulation of antigen uptake/processing and phagocytosis, two central innate immune pathways, by candidate lncRNA was assessed in M1/M2 Mφ. Compared to scramble, enhanced antigen uptake and processing were observed in both M1/M2 Mφ transfected with siRNA targeting GAS5 and RN7SK but not IPW and ZFAS1. In addition, knockdown of RN7SK significantly augmented uptake of labelled E. coli in vitro by M1/M2 Mφ, while no significant difference was in GAS5 silencing cells. Together, our results highlight the instrumental role of lncRNA (RN7SK and GAS5)-mediated epigenetic regulation of macrophage differentiation, polarization, and innate immune functions.

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