Expansion of tumor-infiltrating lymphocytes from head and neck squamous cell carcinoma to assess the potential of adoptive cell therapy.

BACKGROUND: Adoptive transfer of in vitro expanded tumor-infiltrating lymphocytes (TILs) has been effective in regressing several types of malignant tumors. This study assessed the yield and factors influencing the successful expansion of tumor-infiltrating lymphocytes (TILs) from head and neck squamous cell carcinoma (HNSCC), along with their immune phenotypes. METHODS: TILs were expanded from 47 surgically resected HNSCC specimens and their metastasized lymph nodes. The cancer tissues were cut into small pieces (1-2 mm) and underwent initial expansion for 2 weeks. Tumor location, smoking history, stromal TIL percentage, human papillomavirus infection, and programmed death-ligand 1 score were examined for their impact on successful expansion of TILs. Expanded TILs were evaluated by flow cytometry using fluorescence-activated cell sorting. A second round of TIL expansion following the rapid expansion protocol was performed on a subset of samples with successful TIL expansion. RESULTS: TILs were successfully expanded from 36.2% samples. Failure was due to contamination (27.6%) or insufficient expansion (36.2%). Only the stromal TIL percentage was significantly associated with successful TIL expansion (p = 0.032). The stromal TIL percentage also displayed a correlation with the expanded TILs per fragment (r = 0.341, p = 0.048). On flow cytometry analysis using 13 samples with successful TIL expansion, CD4 + T cell dominancy was seen in 69.2% of cases. Effector memory T cells were the major phenotype of expanded CD4 + and CD8 + T cells in all cases. CONCLUSION: We could expand TILs from approximately one-third of HNSCC samples. TIL expansion could be applicable in HNSCC samples with diverse clinicopathological characteristics.

Characterization of Th17 tissue-resident memory cells in non-inflamed intestinal tissue of Crohn's disease patients.

Crohn's disease (CD) is a chronic inflammatory disorder affecting the bowel wall. Tissue-resident memory T (Trm) cells are implicated in CD, yet their characteristics remain unclear. We aimed to investigate the transcriptional profiles and functional characteristics of Trm cells in the small bowel of CD and their interactions with immune cells. Seven patients with CD and four with ulcerative colitis as controls were included. Single-cell RNA sequencing and paired T cell receptor sequencing assessed T cell subsets and transcriptional signatures in lamina propria (LP) and submucosa/muscularis propria-enriched fractions (SM/MP) from small bowel tissue samples. We detected 58,123 T cells grouped into 16 populations, including the CD4+ Trm cells with a Th17 signature and CD8+ Trm clusters. In CD, CD4+ Trm cells with a Th17 signature, termed Th17 Trm, showed significantly increased proportions within both the LP and SM/MP areas. The Th17 Trm cluster demonstrated heightened expression of tissue-residency marker genes (ITGAE, ITGA1, and CXCR6) along with elevated levels of IL17A, IL22, CCR6, and CCL20. The clonal expansion of Th17 Trm cells in CD was accompanied by enhanced transmural dynamic potential, as indicated by significantly higher migration scores. CD-prominent Th17 Trm cells displayed an increased interferon gamma (IFNγ)-related signature possibly linked with STAT1 activation, inducing chemokines (i.e., CXCL10, CXCL8, and CXCL9) in myeloid cells. Our findings underscored the elevated Th17 Trm cells throughout the small bowel in CD, contributing to disease pathogenesis through IFNγ induction and subsequent chemokine production in myeloid cells.

Newly isolated Lactobacillus paracasei strain modulates lung immunity and improves the capacity to cope with influenza virus infection.

BACKGROUND: The modulation of immune responses by probiotics is crucial for local and systemic immunity. Recent studies have suggested a correlation between gut microbiota and lung immunity, known as the gut-lung axis. However, the evidence and mechanisms underlying this axis remain elusive. RESULTS: In this study, we screened various Lactobacillus (L.) strains for their ability to augment type I interferon (IFN-I) signaling using an IFN-α/ß reporter cell line. We identified L. paracasei (MI29) from the feces of healthy volunteers, which showed enhanced IFN-I signaling in vitro. Oral administration of the MI29 strain to wild-type B6 mice for 2 weeks resulted in increased expression of IFN-stimulated genes and pro-inflammatory cytokines in the lungs. We found that MI29-treated mice had significantly increased numbers of CD11c+PDCA-1+ plasmacytoid dendritic cells and Ly6Chi monocytes in the lungs compared with control groups. Pre-treatment with MI29 for 2 weeks resulted in less weight loss and lower viral loads in the lung after a sub-lethal dose of influenza virus infection. Interestingly, IFNAR1-/- mice did not show enhanced viral resistance in response to oral MI29 administration. Furthermore, metabolic profiles of MI29-treated mice revealed changes in fatty acid metabolism, with MI29-derived fatty acids contributing to host defense in a Gpr40/120-dependent manner. CONCLUSIONS: These findings suggest that the newly isolated MI29 strain can activate host defense immunity and prevent infections caused by the influenza virus through the gut-lung axis. Video Abstract.

Gut microbiome on immune checkpoint inhibitor therapy and consequent immune-related colitis: a review.

Immune checkpoint inhibitors have dramatically revolutionized the therapeutic landscape for patients with advanced malignancies. Recently, convincing evidence has shown meaningful influence of gut microbiome on human immune system. With the complex link between gut microbiome, host immunity and cancer, the variations in the gut microbiota may influence the efficacy of immune checkpoint inhibitors. Indeed, some bacterial species have been reported to be predictive for cancer outcome in patients treated with immune checkpoint inhibitors. Although immune checkpoint inhibitors are currently proven to be an effective anti-tumor treatment, they can induce a distinct form of toxicity, termed immune-related adverse events. Immune-related colitis is one of the common toxicities from immune checkpoint inhibitors, and it might preclude the cancer therapy in severe or refractory cases. The manipulation of gut microbiome by fecal microbiota transplantation or probiotics administration has been suggested as one of the methods to enhance anti-tumor effects and decrease the risk of immune-related colitis. Here we review the role of gut microbiome on immune checkpoint inhibitor therapy and consequent immune-related colitis to provide a new insight for better anti-cancer therapy.

Forkhead box protein D2 suppresses colorectal cancer by reprogramming enhancer interactions.

Somatic stem cells contribute to normal tissue homeostasis, and their epigenomic features play an important role in regulating tissue identities or developing disease states. Enhancers are one of the key players controlling chromatin context-specific gene expression in a spatial and temporal manner while maintaining tissue homeostasis, and their dysregulation leads to tumorigenesis. Here, epigenomic and transcriptomic analyses reveal that forkhead box protein D2 (FOXD2) is a hub for the gene regulatory network exclusive to large intestinal stem cells, and its overexpression plays a significant role in colon cancer regression. FOXD2 is positioned at the closed chromatin and facilitates mixed-lineage leukemia protein-4 (MLL4/KMT2D) binding to deposit H3K4 monomethylation. De novo FOXD2-mediated chromatin interactions rewire the regulation of p53-responsive genes and induction of apoptosis. Taken together, our findings illustrate the novel mechanistic details of FOXD2 in suppressing colorectal cancer growth and suggest its function as a chromatin-tuning factor and a potential therapeutic target for colorectal cancer.

Gut microbiota alterations in critically Ill patients with carbapenem-resistant Enterobacteriaceae colonization: A clinical analysis.

Background: Carbapenem-resistant Enterobacteriaceae (CRE) are an emerging concern for global health and are associated with high morbidity and mortality in critically ill patients. Risk factors for CRE acquisition include broad-spectrum antibiotic use and microbiota dysbiosis in critically ill patients. Therefore, we evaluated the alteration of the intestinal microbiota associated with CRE colonization in critically ill patients. Methods: Fecal samples of 41 patients who were diagnosed with septic shock or respiratory failure were collected after their admission to the intensive care unit (ICU). The gut microbiota profile determined using 16S rRNA gene sequencing and quantitative measurement of fecal short-chain fatty acids were evaluated in CRE-positive (n = 9) and CRE negative (n = 32) patients. The analysis of bacterial metabolic abundance to identify an association between CRE acquisition and metabolic pathway was performed. Results: CRE carriers showed a significantly increased proportion of the phyla Proteobacteria and decreased numbers of the phyla Bacteroidetes as compared to the CRE non-carriers. Linear discriminant analysis (LDA) with linear discriminant effect size showed that the genera Erwinia, Citrobacter, Klebsiella, Cronobacter, Kluyvera, Dysgomonas, Pantoea, and Alistipes had an upper 2 LDA score in CRE carriers. The alpha-diversity indices were significantly decreased in CRE carriers, and beta-diversity analysis demonstrated that the two groups were clustered significantly apart. Among short-chain fatty acids, the levels of isobutyric acid and valeric acid were significantly decreased in CRE carriers. Furthermore, the PICRUSt-predicted metabolic pathways revealed significant differences in five features, including ATP-binding cassette transporters, phosphotransferase systems, sphingolipid metabolism, other glycan degradation, and microbial metabolism, in diverse environments between the two groups. Conclusion: Critically ill patients with CRE have a distinctive gut microbiota composition and community structure, altered short-chain fatty acid production and changes in the metabolic pathways. Further studies are needed to determine whether amino acids supplementation improves microbiota dysbiosis in patients with CRE.

LKB1 in Intestinal Epithelial Cells Regulates Bile Acid Metabolism by Modulating FGF15/19 Production.

BACKGROUND & AIMS: Liver kinase B1 (LKB1) is a master upstream protein kinase involved in nutrient sensing and glucose and lipid metabolism in many tissues; however, its metabolic role in intestinal epithelial cells (IEC) remains unclear. In this study, we investigated the regulatory role of LKB1 on bile acid (BA) homeostasis. METHODS: We generated mice with IEC-specific deletion of LKB1 (LKB1ΔIEC) and analyzed the characteristics of IEC development and BA level. In vitro assays with small interfering RNA, liquid chromatography/mass spectrometry, metagenomics, and RNA-sequencing were used to elucidate the regulatory mechanisms underlying perturbed BA homeostasis. RESULTS: LKB1 deletion resulted in abnormal differentiation of secretory cell lineages. Unexpectedly, BA pool size increased substantially in LKB1ΔIEC mice. A significant reduction of the farnesoid X receptor (FXR) target genes, including fibroblast growth factor 15/19 (FGF15/19), known to inhibit BA synthesis, was found in the small intestine (SI) ileum of LKB1ΔIEC mice. We observed that LKB1 depletion reduced FGF15/19 protein level in human IECs in vitro. Additionally, a lower abundance of bile salt hydrolase-producing bacteria and elevated levels of FXR antagonist (ie, T-ßMCA) were observed in the SI of LKB1ΔIEC mice. Moreover, LKB1ΔIEC mice showed impaired conversion of retinol to retinoic acids in the SI ileum. Subsequently, vitamin A treatment failed to induce FGF15 production. Thus, LKB1ΔIEC mice fed with a high-fat diet showed improved glucose tolerance and increased energy expenditure. CONCLUSIONS: LKB1 in IECs manages BA homeostasis by controlling FGF15/19 production.

PET Imaging of System xC - in Immune Cells for Assessment of Disease Activity in Mice and Patients with Inflammatory Bowel Disease.

We aimed to explore whether the imaging of antiporter system xC - of immune cells with (4S)-4-(3-18F-fluoropropyl)-l-glutamate (18F-FSPG) PET can assess inflammatory bowel disease (IBD) activity in murine models and patients (NCT03546868). Methods: 18F-FSPG PET imaging was performed to assess IBD activity in mice with dextran sulfate sodium-induced and adoptive T-cell transfer-induced IBD and a cohort of 20 patients at a tertiary care center in South Korea. Immunohistochemical analysis of system xC - and cell surface markers was also studied. Results: Mice with experimental IBD showed increased intestinal 18F-FSPG uptake and xCT expression in cells positive (+) for CD11c, F4/80, and CD3 in the lamina propria, increases positively associated with clinical and pathologic disease activity. 18F-FSPG PET studies in patients, most of whom were clinically in remission or had mildly active IBD, showed that PET imaging was sufficiently accurate in diagnosing endoscopically active IBD and remission in patients and bowel segments. 18F-FSPG PET correctly identified all 9 patients with superficial or deep ulcers. Quantitative intestinal 18F-FSPG uptake was strongly associated with endoscopic indices of IBD activity. The number of CD68+xCT+ and CD3+xCT+ cells in 22 bowel segments from patients with ulcerative colitis and the number of CD68+xCT+ cells in 7 bowel segments from patients with Crohn disease showed a significant positive association with endoscopic indices of IBD activity. Conclusion: The assessment of system xC - in immune cells may provide diagnostic information on the immune responses responsible for chronic active inflammation in IBD. 18F-FSPG PET imaging of system xC - activity may noninvasively assess the IBD activity.

A High-Fat Diet Activates the BAs-FXR Axis and Triggers Cancer-Associated Fibroblast Properties in the Colon.

BACKGROUND & AIMS: Dietary signals are known to modulate stemness and tumorigenicity of intestinal progenitors; however, the impact of a high-fat diet (HFD) on the intestinal stem cell (ISC) niche and its association with colorectal cancer remains unclear. Thus, we aimed to investigate how a HFD affects the ISC niche and its regulatory factors. METHODS: Mice were fed a purified diet (PD) or HFD for 2 months. The expression levels of ISC-related markers, ISC-supportive signals, and Wnt2b were assessed with real-time quantitative polymerase chain reaction, in situ hybridization, and immunofluorescence staining. RNA sequencing and metabolic function were analyzed in mesenchymal stromal cells (MSCs) from PD- and HFD-fed mice. Fecal microbiota were analyzed by 16s rRNA sequencing. Bile salt hydrolase activity and bile acid (BA) levels were measured. RESULTS: We found that expression of CD44 and Wnt signal-related genes was higher in the colonic crypts of HFD-fed mice than in those fed a PD. Within the ISC niche, MSCs were expanded and secreted predominant levels of Wnt2b in the colon of HFD-fed mice. Of note, increased energy metabolism and cancer-associated fibroblast (CAF)-like properties were found in the colonic MSCs of HFD-fed mice. Moreover, colonic MSCs from HFD-fed mice promoted the growth of tumorigenic properties and accelerated the expression of cancer stem cell (CSC)-related markers in colon organoids. In particular, production of primary and secondary BAs was increased through the expansion of bile salt hydrolase-encoding bacteria in HFD-fed mice. Most importantly, BAs-FXR interaction stimulated Wnt2b production in colonic CAF-like MSCs. CONCLUSIONS: HFD-induced colonic CAF-like MSCs play an indispensable role in balancing the properties of CSCs through activation of the BAs-FXR axis.

Bleomycin-Induced Lung Injury Increases Resistance to Influenza Virus Infection in a Type I Interferon-Dependent Manner.

Acute lung injury (ALI) results in acute respiratory disease that causes fatal respiratory diseases; however, little is known about the incidence of influenza infection in ALI. Using a ALI-mouse model, we investigated the pro-inflammatory cytokine response to ALI and influenza infection. Mice treated with bleomycin (BLM), which induces ALI, were more resistant to influenza virus infection and exhibited higher levels of type I interferon (IFN-I) transcription during the early infection period than that in PBS-treated control mice. BLM-treated mice also exhibited a lower viral burden, reduced pro-inflammatory cytokine production, and neutrophil levels. In contrast, BLM-treated IFN-I receptor 1 (IFNAR1)-knockout mice failed to show this attenuated phenotype, indicating that IFN-I is key to the antiviral response in ALI-induced mice. The STING/TBK1/IRF3 pathway was found to be involved in IFN-I production and the establishment of an antiviral environment in the lung. The depletion of plasmacytoid dendritic cells (pDCs) reduced the effect of BLM treatment against influenza virus infection, suggesting that pDCs are the major source of IFN-I and are crucial for defense against viral infection in BLM-induced lung injury. Overall, this study showed that BLM-mediated ALI in mice induced the release of double-stranded DNA, which in turn potentiated IFN-I-dependent pulmonary viral resistance by activating the STING/TBK1/IRF3 pathway in association with pDCs.

Microbiota-derived lactate promotes hematopoiesis and erythropoiesis by inducing stem cell factor production from leptin receptor+ niche cells.

Although functional interplay between intestinal microbiota and distant sites beyond the gut has been identified, the influence of microbiota-derived metabolites on hematopoietic stem cells (HSCs) remains unclear. This study investigated the role of microbiota-derived lactate in hematopoiesis using mice deficient in G-protein-coupled receptor (Gpr) 81 (Gpr81-/-), an established lactate receptor. We detected significant depletion of total HSCs in the bone marrow (BM) of Gpr81-/- mice compared with heterogenic (Gpr81+/-) mice in a steady state. Notably, the expression levels of stem cell factor (SCF), which is required for the proliferation of HSCs, decreased significantly in leptin receptor-expressing (LepR+) mesenchymal stromal cells (MSCs) around the sinusoidal vessels of the BM from Gpr81-/- mice compared with Gpr81+/- mice. Hematopoietic recovery and activation of BM niche cells after irradiation or busulfan treatment also required Gpr81 signals. Oral administration of lactic acid-producing bacteria (LAB) activated SCF secretion from LepR+ BM MSCs and subsequently accelerated hematopoiesis and erythropoiesis. Most importantly, LAB feeding accelerated the self-renewal of HSCs in germ-free mice. These results suggest that microbiota-derived lactate stimulates SCF secretion by LepR+ BM MSCs and subsequently activates hematopoiesis and erythropoiesis in a Gpr81-dependent manner.

Mucin degrader Akkermansia muciniphila accelerates intestinal stem cell-mediated epithelial development.

Mucin-degrading bacteria are densely populated in the intestinal epithelium; however, their interaction with intestinal stem cells (ISCs) and their progeny have not been elucidated. To determine whether mucin-degrading bacteria play a role in gut homeostasis, mice were treated with Akkermansia muciniphila, a specialized species that degrades mucin. Administration of A. muciniphila for 4 weeks accelerated the proliferation of Lgr5+ ISCs and promoted the differentiation of Paneth cells and goblet cells in the small intestine (SI). We found similar effects of A. muciniphila in the colon. The levels of acetic and propionic acids were higher in the cecal contents of A. muciniphila-treated mice than in PBS-treated mice. SI organoids treated with cecal contents obtained from A. muciniphila-treated mice were larger and could be diminished by treatment with G protein-coupled receptor (Gpr) 41/43 antagonists. Pre-treatment of mice with A. muciniphila reduced gut damage caused by radiation and methotrexate. Further, a novel isotype of the A. muciniphila strain was isolated from heathy human feces that showed enhanced function in intestinal epithelial regeneration. These findings suggest that mucin-degrading bacteria (e.g., A. muciniphila) may play a crucial role in promoting ISC-mediated epithelial development and contribute to intestinal homeostasis maintenance.

Geranylgeranyl pyrophosphate amplifies Treg differentiation via increased IL-2 expression to ameliorate DSS-induced colitis.

Blocking the mevalonate pathway for cholesterol reduction by using statin may have adverse effects including statin-induced colitis. Moreover, one of the predisposing factors for colitis is an imbalanced CD4+ T cell, which can be observed on the complete deletion of HMG-CoA reductase (HMGCR), a target of statins. In this study, we inquired geranylgeranyl pyrophosphate (GGPP) is responsible for maintaining the T-cell homeostasis. Following dextran sulfate sodium (DSS)-induced colitis, simvastatin increased the severity of disease, while cotreatment with GGPP, but not with cholesterol, reversed the disease magnitude. GGPP ameliorated DSS-induced colitis by increasing Treg cells. GGPP amplified Treg differentiation through increased IL-2/STAT 5 signaling. GGPP prenylated Ras protein, a prerequisite for extracellular signal-regulated kinase (ERK) pathway activation, leading to increased IL-2 production. Higher simvastatin dose increased the severity of colitis. GGPP ameliorated simvastatin-increased colitis by increasing Treg cells. Treg cells, which have the capacity to suppress inflammatory T cells and were generated through IL-2/STAT5 signaling, increased IL-2 production through prenylation and activation of the Ras/ERK pathway.

Plasmacytoid dendritic cells regulate colitis-associated tumorigenesis by controlling myeloid-derived suppressor cell infiltration.

Toll-like receptor (TLR)3 and TLR7 are important for stimulating plasmacytoid dendritic cells (pDCs), which secrete type I interferon. Mice deficient for TLR3 and TLR7 (TLR3-/-TLR7-/-) reportedly exhibit deteriorated colitis because of impaired pDCs. However, the role of pDCs in tumorigenesis-associated inflammation progression has not been studied. We treated wild-type or TLR3-/-TLR7-/- mice with dextran sulfate sodium (DSS) and/or azoxymethane (AOM) and examined colon mucosa, measured body weight and colon length of mice, and examined pDC and myeloid-derived suppressor cell (MDSC) accumulation. Further, we depleted pDCs in AOM/DSS-treated wild-type mice by treating them with anti-PDCA-1 antibodies. We found that MDSCs significantly increased, while pDCs decreased in TLR3-/-TLR7-/- mice. Moreover, TLR3-/-TLR7-/- mice developed colitis-associated colon cancer following AOM/DSS treatment. Additionally, we showed that a defect in TLR7 of pDCs is responsible for the aggravation of colitis-associated colon cancer. Further, we showed that TLR7 ligand mitigates colitis-associated colon cancer. Collectively, our results demonstrate that gut pDCs play a crucial role in reducing colorectal cancer development via the regulation of infiltrating MDSCs.

Iroquois Homeobox Protein 2 Identified as a Potential Biomarker for Parkinson's Disease.

The diagnosis of Parkinson's disease (PD) is initiated after the occurrence of motor symptoms, such as resting tremors, rigidity, and bradykinesia. According to previous reports, non-motor symptoms, notably gastrointestinal dysfunction, could potentially be early biomarkers in PD patients as such symptoms occur earlier than motor symptoms. However, connecting PD to the intestine is methodologically challenging. Thus, we generated in vitro human intestinal organoids from PD patients and ex vivo mouse small intestinal organoids from aged transgenic mice. Both intestinal organoids (IOs) contained the human LRRK2 G2019S mutation, which is the most frequent genetic cause of familial and sporadic PD. By conducting comprehensive genomic comparisons with these two types of IOs, we determined that a particular gene, namely, Iroquois homeobox protein 2 (IRX2), showed PD-related expression patterns not only in human pluripotent stem cell (PSC)-derived neuroectodermal spheres but also in human PSC-derived neuronal cells containing dopaminergic neurons. We expected that our approach of using various cell types presented a novel technical method for studying the effects of multi-organs in PD pathophysiology as well as for the development of diagnostic markers for PD.

Dietary cellulose prevents gut inflammation by modulating lipid metabolism and gut microbiota.

A Western diet comprising high fat, high carbohydrate, and low fiber content has been suggested to contribute to an increased prevalence of colitis. To clarify the effect of dietary cellulose (an insoluble fiber) on gut homeostasis, for 3 months mice were fed a high-cellulose diet (HCD) or a low-cellulose diet (LCD) based on the AIN-93G formulation. Histologic evaluation showed crypt atrophy and goblet cell depletion in the colons of LCD-fed mice. RNA-sequencing analysis showed a higher expression of genes associated with immune system processes, especially those of chemokines and their receptors, in the colon tissues of LCD-fed mice than in those of HCD-fed mice. The HCD was protective against dextran sodium sulfate-induced colitis in mice, while LCD exacerbated gut inflammation; however, the depletion of gut microbiota by antibiotic treatment diminished both beneficial and non-beneficial effects of the HCD and LCD on colitis, respectively. A comparative analysis of the cecal contents of mice fed the HCD or the LCD showed that the LCD did not influence the diversity of gut microbiota, but it resulted in a higher and lower abundance of Oscillibacter and Akkermansia organisms, respectively. Additionally, linoleic acid, nicotinate, and nicotinamide pathways were most affected by cellulose intake, while the levels of short-chain fatty acids were comparable in HCD- and LCD-fed mice. Finally, oral administration of Akkermansia muciniphila to LCD-fed mice elevated crypt length, increased goblet cells, and ameliorated colitis. These results suggest that dietary cellulose plays a beneficial role in maintaining gut homeostasis through the alteration of gut microbiota and metabolites.

IκBζ controls NLRP3 inflammasome activation via upregulation of the Nlrp3 gene.

Inflammasome activation induces the maturation and secretion of interleukin (IL)-1ß and -18, and is dependent on NF-κB signaling to induce the transcription of the inflammasome components, called the priming step. This study elucidated the role of IκBζ, an atypical IκBs (inhibitor of κB) and a coactivator of NF-κB target genes, on the activation of inflammasome. Bone marrow-derived macrophages (BMDMs) that originated from IκBζ-encoding Nfkbiz gene depletion mice presented a defect in NLRP3 inflammasome activation. In addition, the Nfkbiz+/- and Nfkbiz-/- mice significantly attenuated serum IL-1ß secretion in response to a monosodium urate injection, a NLRP3 trigger, when compared with Nfkbiz-+/+ mice. The lack of IκBζ in BMDMs produced a disability in the expression of Nlrp3 and pro-Il1ß mRNAs during the priming step. In addition, ectopic IκBζ expression enhanced the Nlrp3 promoter activity, and Nlrp3 and pro-Il1ß transcription. Overall, IκBζ controlled the activation of NLRP3 inflammasome by upregulating the Nlrp3 gene during the priming step.

Roseburia spp. Abundance Associates with Alcohol Consumption in Humans and Its Administration Ameliorates Alcoholic Fatty Liver in Mice.

Although a link between the gut microbiota and alcohol-related liver diseases (ALDs) has previously been suggested, the causative effects of specific taxa and their functions have not been fully investigated to date. Here, we analyze the gut microbiota of 410 fecal samples from 212 Korean twins by using the Alcohol Use Disorders Identification Test (AUDIT) scales to adjust for host genetics. This analysis revealed a strong association between low AUDIT scores and the abundance of the butyrate-producing genus Roseburia. When Roseburia spp. are administered to ALD murine models, both hepatic steatosis and inflammation significantly improve regardless of bacterial viability. Specifically, the flagellin of R. intestinalis, possibly through Toll-like receptor 5 (TLR5) recognition, recovers gut barrier integrity through upregulation of the tight junction protein Occludin and helps to restore the gut microbiota through elevated expression of IL-22 and REG3γ. Our study demonstrates that Roseburia spp. improve the gut ecosystem and prevent leaky gut, leading to ameliorated ALDs.

Anoctamin 1/TMEM16A controls intestinal Cl- secretion induced by carbachol and cholera toxin.

Calcium-activated chloride channels (CaCCs) mediate numerous physiological functions and are best known for the transport of electrolytes and water in epithelia. In the intestine, CaCC currents are considered necessary for the secretion of fluid to protect the intestinal epithelium. Although genetic ablation of ANO1/TMEM16A, a gene encoding a CaCC, reduces the carbachol-induced secretion of intestinal fluid, its mechanism of action is still unknown. Here, we confirm that ANO1 is essential for the secretion of intestinal fluid. Carbachol-induced transepithelial currents were reduced in the proximal colon of Ano1-deficient mice. Surprisingly, cholera toxin-induced and cAMP-induced fluid secretion, believed to be mediated by CFTR, were also significantly reduced in the intestine of Ano1-deficient mice. ANO1 is largely expressed in the apical membranes of intestines, as predicted for CaCCs. The Ano1-deficient colons became edematous under basal conditions and had a greater susceptibility to dextran sodium sulfate-induced colitis. However, Ano1 depletion failed to affect tumor development in a model of colorectal cancer. We thus conclude that ANO1 is necessary for cAMP- and carbachol-induced Cl- secretion in the intestine, which is essential for the protection of the intestinal epithelium from colitis.

Virome-host interactions in intestinal health and disease.

The enteric virome consists largely of bacteriophages and prophages related to commensal bacteria. Bacteriophages indirectly affect the host immune system by targeting their associated bacteria; however, studies suggest that bacteriophages also have distinct pathways that enable them to interact directly with the host. Eukaryotic viruses are less abundant than bacteriophages but are more efficient in the stimulation of host immune responses. Acute, permanent, and latent viral infections are detected by different types of pattern recognition receptors and induce host immune responses, including the antiviral type I interferon response. Understanding the complex interplay between commensal microorganisms and the host immune system is a prerequisite to elucidating their role in intestinal diseases.