The gastrointestinal tract is known as the largest endocrine organ that encounters and integrates various immune stimulations and neuronal responses due to constant environmental challenges. ...Enterochromaffin (EC) cells, which function as chemosensors on the gut epithelium, are known to translate environmental cues into serotonin (5-HT) production, contributing to intestinal physiology. However, how immune signals participate in gut sensation and neuroendocrine response remains unclear. Interleukin-33 (IL-33) acts as an alarmin cytokine by alerting the system of potential environmental stresses. We here demonstrate that IL-33 induced instantaneous peristaltic movement and facilitated Trichuris muris expulsion. We found that IL-33 could be sensed by EC cells, inducing release of 5-HT. IL-33-mediated 5-HT release activated enteric neurons, subsequently promoting gut motility. Mechanistically, IL-33 triggered calcium influx via a non-canonical signaling pathway specifically in EC cells to induce 5-HT secretion. Our data establish an immune-neuroendocrine axis in calibrating rapid 5-HT release for intestinal homeostasis.
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•IL-33-ST2 signaling regulates gut motility and intestinal host defense•Enterochromaffin (EC) cell-derived ST2 responds to IL-33 for 5-HT release•TRPA1 is required for IL-33-mediated 5-HT release•IL-33 induces PLC-γ1 activation for 5-HT release in both mouse and human EC cells
Enterochromaffin (EC) cells are known to act as chemosensors on the gut epithelium, translating environmental cues into serotonin (5-HT) production. Chen et al. demonstrate that an alarmin cytokine IL-33 could be sensed by EC cells, inducing release of 5-HT, regulating intestinal homeostasis and host defense.
Gut-innervating nociceptor sensory neurons respond to noxious stimuli by initiating protective responses including pain and inflammation; however, their role in enteric infections is unclear. Here, ...we find that nociceptor neurons critically mediate host defense against the bacterial pathogen Salmonella enterica serovar Typhimurium (STm). Dorsal root ganglia nociceptors protect against STm colonization, invasion, and dissemination from the gut. Nociceptors regulate the density of microfold (M) cells in ileum Peyer’s patch (PP) follicle-associated epithelia (FAE) to limit entry points for STm invasion. Downstream of M cells, nociceptors maintain levels of segmentous filamentous bacteria (SFB), a gut microbe residing on ileum villi and PP FAE that mediates resistance to STm infection. TRPV1+ nociceptors directly respond to STm by releasing calcitonin gene-related peptide (CGRP), a neuropeptide that modulates M cells and SFB levels to protect against Salmonella infection. These findings reveal a major role for nociceptor neurons in sensing and defending against enteric pathogens.
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•Nociceptors mediate enteric defense against Salmonella colonization and PP invasion•Nociceptors shape the gut microbiota and SFB levels to resist Salmonella infection•Nociceptors suppress M cell density to regulate SFB and limit bacterial invasion•Nociceptors directly sense Salmonella to release CGRP to promote host defense
Extrinsic nociceptor neurons mediate protection from Salmonella infection by direct sensing and release of CGRP, which leads to suppression of M cell density and maintenance of SFB colonization of the ileum.
A balance between Th17 and regulatory T (Treg) cells is critical for immune homeostasis and tolerance. Our previous work has shown Serum- and glucocorticoid-induced kinase 1 (SGK1) is critical for ...the development and function of Th17 cells. Here, we show that SGK1 restrains the function of Treg cells and reciprocally regulates development of Th17/Treg balance. SGK1 deficiency leads to protection against autoimmunity and enhances self-tolerance by promoting Treg cell development and disarming Th17 cells. Treg cell-specific deletion of SGK1 results in enhanced Treg cell-suppressive function through preventing Foxo1 out of the nucleus, thereby promoting Foxp3 expression by binding to Foxp3 CNS1 region. Furthermore, our data suggest that SGK1 also plays a critical role in IL-23R-mediated inhibition of Treg and development of Th17 cells. Therefore, we demonstrate that SGK1 functions as a pivotal node in regulating the reciprocal development of pro-inflammatory Th17 and Foxp3+ Treg cells during autoimmune tissue inflammation.
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•SGK1 restrains Treg cell expansion and function•SGK1 represses Foxp3 expression via regulating IL-23R•SGK1 reciprocally regulates development of Th17/Treg balance•SGK1 restrains Foxp3 expression via reduced Foxo1 nuclear exclusion
Wu et al. demonstrated that SGK1 regulates Treg function in a cell-intrinsic manner. SGK1 functions as a pivotal node in regulating the balance of pro-inflammatory Th17 cells and regulatory Foxp3+ T cells during autoimmune reactions.
Significance Treg cells suppress excessive and aberrant immune responses. Impaired function or homeostasis of Treg cells would induce severe autoimmune and inflammatory diseases. Forkhead box P3 ...(FOXP3), as a master regulator of Treg cells, forms a large complex with other binding factors to modulate Treg-cell function subtly in pathological and physiological conditions. We identified that Deleted in breast cancer 1 (DBC1) is an essential subunit of the FOXP3 complex in human CD4 ⺠Treg cells. Our results show that the inflammatory cytokines TNF-α or IL-6 trigger FOXP3 degradation, whereas downregulation of DBC1 expression prevents FOXP3 degradation and maintains Treg-cell function under inflammatory stimuli in vitro and in vivo. These findings unveil a previously unidentified pathway for therapeutically modulating FOXP3 ⺠Treg-cell stability under inflammation.
Forkhead box P3 (FOXP3)-positive Treg cells are crucial for maintaining immune homeostasis. FOXP3 cooperates with its binding partners to elicit Treg cellsâ signature and function, but the molecular mechanisms underlying the modulation of the FOXP3 complex remain unclear. Here we report that Deleted in breast cancer 1 (DBC1) is a key subunit of the FOXP3 complex. We found that DBC1 interacts physically with FOXP3, and depletion of DBC1 attenuates FOXP3 degradation in inflammatory conditions. Treg cells from Dbc1-deficient mice were more resistant to inflammation-mediated abrogation of Foxp3 expression and function and delayed the onset and severity of experimental autoimmune encephalomyelitis and colitis in mice. These findings establish a previously unidentified mechanism regulating FOXP3 stability during inflammation and reveal a pathway for potential therapeutic modulation and intervention in inflammatory diseases.
Mucus produced by goblet cells in the gastrointestinal tract forms a biological barrier that protects the intestine from invasion by commensals and pathogens. However, the host-derived regulatory ...network that controls mucus secretion and thereby changes gut microbiota has not been well studied. Here, we identify that Forkhead box protein O1 (Foxo1) regulates mucus secretion by goblet cells and determines intestinal homeostasis. Loss of Foxo1 in intestinal epithelial cells (IECs) results in defects in goblet cell autophagy and mucus secretion, leading to an impaired gut microenvironment and dysbiosis. Subsequently, due to changes in microbiota and disruption in microbiome metabolites of short-chain fatty acids, Foxo1 deficiency results in altered organization of tight junction proteins and enhanced susceptibility to intestinal inflammation. Our study demonstrates that Foxo1 is crucial for IECs to establish commensalism and maintain intestinal barrier integrity by regulating goblet cell function.
Interleukin-9 (IL-9)-producing CD4
T helper cells (Th9) have been implicated in allergy/asthma and anti-tumor immunity, yet molecular insights on their differentiation from activated T cells, driven ...by IL-4 and transforming growth factor-beta (TGF-β), is still lacking. Here we show opposing functions of two transcription factors, D-binding protein (DBP) and E2F8, in controlling Th9 differentiation. Specifically, TGF-β and IL-4 signaling induces phosphorylation of the serine 213 site in the linker region of the Smad3 (pSmad3L-Ser
) via phosphorylated p38, which is necessary and sufficient for Il9 gene transcription. We identify DBP and E2F8 as an activator and repressor, respectively, for Il9 transcription by pSmad3L-Ser
. Notably, Th9 cells with siRNA-mediated knockdown for Dbp or E2f8 promote and suppress tumor growth, respectively, in mouse tumor models. Importantly, DBP and E2F8 also exhibit opposing functions in regulating human TH9 differentiation in vitro. Thus, our data uncover a molecular mechanism of Smad3 linker region-mediated, opposing functions of DBP and E2F8 in Th9 differentiation.
The helper CD4
T cell-type 17 (Th17) cells and regulatory CD4
T cells (Tregs) are balanced through numerous molecular regulators, particularly metabolic factors, and their alteration causes immune ...dysregulation. Herein, we report that peroxisome proliferator of activated receptor-alpha (Pparα), a lipid metabolism regulator, suppresses Th17 differentiation. We demonstrated that Pparα ablation improves Th17 and pro-Th17 factor HIF-1α by enhancing the expression and nuclear localization of NFκB-activator IκB kinase-alpha (IKKα). Unexpectedly, we found that IKKα directly interacts with RORγt and enhances the expression of Il17a gene. Meanwhile, IKKα also interacts with Foxp3, leading to the post-translational regulation of Foxp3 by elevating its proteasomal degradation, and influencing Th17 development. Pparα deficiency leads to enhanced Th17 development in vivo and is associated with enhanced pathology in a murine experimental autoimmune encephalomyelitis (EAE) model. Overall, our data indicate that Pparα may serve as a potential therapeutic target for autoimmune and inflammatory diseases.
FOXP3
+CD4
+CD25
+ Regulatory T (Treg) cells and IL-17 producing helper T cells (Th17) are critical subsets of T cells which play essential roles in immune homeostasis. The Forkhead family ...transcription factor FOXP3 is predominantly expressed in Treg cells, where the FOXP3 ensemble is essential for Treg cell development and function. As FOXP3 is to Treg cells, the orphan retinoic acid nuclear receptor (ROR) family transcription factor RORγt is essential for Th17 development and function. In this review, we summarize recent progress of our understanding towards the molecular mechanisms underlying the differentiation and function of FOXP3
+ Treg cells and RORγt expressing Th17 cells. These may provide new insights into therapeutic intervention and targeting of human immune-deficient diseases.
Although lysine methylation is classically known to regulate histone function, its role in modulating antiviral restriction factor activity remains uncharacterized. Interferon-induced transmembrane ...protein 3 (IFITM3) was found monomethylated on its lysine 88 residue (IFITM3-K88me1) to reduce its antiviral activity, mediated by the lysine methyltransferase SET7. Vesicular stomatitis virus and influenza A virus infection increased IFITM3-K88me1 levels by promoting the interaction between IFITM3 and SET7, suggesting that this pathway could be hijacked to support infection; conversely, IFN-α reduced IFITM3-K88me1 levels. These findings may have important implications in the design of therapeutics targeting protein methylation against infectious diseases.
Background: IFITM3 is a general antiviral host restriction factor against RNA viruses.
Results: SET7-mediated monomethylation of IFITM3 at Lys-88 negatively affected its antiviral activity toward vesicular stomatitis virus (VSV) and influenza A virus (IAV) infection.
Conclusion: The monomethylation of antiviral host restriction factors may perturb their function.
Significance: Targeting the SET7 pathway could provide new antiviral therapeutic strategies.
Particulate Matter (PM) is known to cause inflammatory responses in human. Although prior studies verified the immunogenicity of PM in cell lines and animal models, the effectors of PM exposure in ...the respiratory system and the regulators of the immunogenicity of PM is not fully elucidated.
To identify the potential effector of PM exposure in human respiratory system and to better understand the biology of the immunogenicity of PM, We performed gene-expression profiling of peripheral blood mononuclear cells from 171 heathy subjects in northern China to identify co-expressed gene modules associated with PM exposure. We inferred transcription factors regulating the co-expression and validated the association to T-cell differentiation in both primary T-cells and mice treated with PM.
We report two transcription factors, IRF4 and STAT3, as regulators of the gene expression in response to PM exposure in human. We confirmed that the activation of IRF4 and STAT3 by PM is strongly associated with imbalanced differentiation of T-cells in the respiratory tracts in a time-sensitive manner in mouse. We also verified the consequential inflammatory responses of the PM exposure. Moreover, we show that the protein levels of phosphorylated IRF4 and STAT3 increase with PM exposure.
Our study suggests the regulatory activities of IRF4 and STAT3 are associated with the Th17-mediated inflammatory responses to PM exposure in the respiratory tracts, which informs the biological background of the immunogenicity of particulate matters.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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