Intestinal CD4 Research Articles

From Gut to Blood: Redistribution of Zonulin in People Living with HIV.

Gastrointestinal mucosal damage due to human immunodeficiency virus (HIV) infection leads to microbial translocation and immune activation, contributing to the development of non-infectious comorbidities (NICM) in people living with HIV (PLWH). Additionally, persistent proviral HIV-1 in the gut-associated lymphatic tissue (GALT) can trigger immunological changes in the epithelial environment, impacting the mucosal barrier. However, the role of zonulin, a modulator of epithelial tight junctions in GALT during HIV infection, remains poorly understood. We measured zonulin in serum and intestinal tissue sections from five treatment-naive (HIV+NAIVE) and 10 cART-treated (HIV+cART) HIV+ individuals, along with 11 controls (CTRL). We compared zonulin levels with clinical characteristics, inflammatory markers (IFN-α, CXCR3, and PD-1), and the viral reservoir in peripheral blood (PB) and terminal ileum (TI). Upon HIV infection, TI was found to harbor more HIV DNA than PB. Circulating zonulin levels were highest in HIV+NAIVE compared to HIV+cART or CTRL. Surprisingly, in the gut tissue sections, zonulin levels were higher in CTRL than in HIV+ individuals. Elevated circulating zonulin levels were found to be correlated with CD4+T-cell depletion in PB and TI, and with intestinal IFN-α. The findings of this study indicate a shift in zonulin levels from the gut to the bloodstream in response to HIV infection. Furthermore, elevated systemic zonulin levels are associated with the depletion of intestinal CD4+ T cells and increased gut inflammation, suggesting a potential link between systemic zonulin and intestinal damage. Gaining insight into the regulation of gut tight junctions during HIV infection could offer valuable understanding for preventing NICM in PLWH.

Peroxisome Proliferator-Activated Receptor δ Suppresses the Cytotoxicity of CD8+ T Cells by Inhibiting RelA DNA-Binding Activity.

The molecular mechanisms regulating CD8+ cytotoxic T lymphocytes (CTL) are not fully understood. Here, we show that the peroxisome proliferator-activated receptor δ (PPARδ) suppresses CTL cytotoxicity by inhibiting RelA DNA binding. Treatment of ApcMin/+ mice with the PPARδ agonist GW501516 reduced the activation of normal and tumor-associated intestinal CD8+ T cells and increased intestinal adenoma burden. PPARδ knockout or knockdown in CTLs increased their cytotoxicity against colorectal cancer cells, whereas overexpression of PPARδ or agonist treatment decreased it. Correspondingly, perforin, granzyme B, and IFNγ protein and mRNA levels were higher in PPARδ knockout or knockdown CTLs and lower in PPARδ overexpressing or agonist-treated CTLs. Mechanistically, we found that PPARδ binds to RelA, interfering with RelA-p50 heterodimer formation in the nucleus, thereby inhibiting its DNA binding in CTLs. Thus, PPARδ is a critical regulator of CTL effector function. Significance: Here, we provide the first direct evidence that PPARδ plays a critical role in suppressing the immune response against tumors by downregulating RelA DNA-binding activity. This results in decreased expression of perforin, granzyme B, and IFNγ. Thus, PPARδ may serve as a valuable target for developing future cancer immunotherapies.

Beneficial effects of Dendrobium officinale National Herbal Drink on metabolic immune crosstalk via regulate SCFAs-Th17/Treg

The development of gut-liver axis metabolic immune crosstalk is intimately associated with intestinal barrier disorder, intestinal SCFAs-Th17/Treg immunological imbalance, and disorders of the gut microbiota. Prior research has discovered that Dendrobium officinale National Herbal Drink (NHD), a traditional Chinese medicine drink with enhanced immunity, may enhance the immunological response in animals with impaired immune systems brought on by cyclophosphamide by repairing intestinal barrier function and controlling turbulence in the gut microbiota. However, whether NHD can further improve the gut-liver axis metabolic immune crosstalk and its related mechanisms need to be systematically studied. The purpose of this study is to clarify the function and mechanism of NHD in enhancing the gut-liver axis metabolic immunological crosstalk brought on by excessive alcohol intake. In this work, we set up a mouse model to analyze the metabolic and immunological crosstalk involving the gut-liver axis across 7 weeks of continuous, excessive drinking. At the same time, high and low doses (20,10 ml/kg) of NHD were given by gavage. The effect of NHD on improving the metabolism of gut-liver axis was evaluated by blood lipid, liver lipid deposition, liver function and intestinal pathophysiology. By measuring serum immunological indices, intestinal barrier, and intestinal immune barrier, the impact of NHD on enhancing immune and intestinal barrier function was assessed. Furthermore, immunohistochemistry, immunofluorescence, 16S rRNA, Western blot, q-PCR and other methods were used to detect gut microbiota, SCFAs-GPR41/43 pathway, intestinal Th17/Treg immune cells and PPAR-α-NPC1L1/SREBP1 pathway to elucidate the mechanism by which NHD enhances the gut-liver axis' metabolic immune crosstalk. Our study demonstrated that NHD has the potential to improve the pathophysiological damage caused by gut-liver axis in model mice. NHD also ameliorated the disorder of lipid metabolism. In addition, it regulated the levels of peripheral blood T cell immunity and serum immune factors. And NHD can restore intestinal mechanical and immune barrier damage. NHD has a favorable impact on the quantity of beneficial bacteria, including uncultured_bacterium_g__norank_f__muribaculacea and uncultured_bacterium_g__Turicibacter. Additionally, it raised the model mice's levels of SCFAs (n-butyric acid, isovaleric acid, etc.). This resulted in the promotion of intestinal GPR41/43-ERK1/2 expression and the reshaping of intestinal CD4+T cell Th17/Treg homeostasis. As a consequence, colon IL-22 and IL-10 levels increased, while colon IL-17A levels decreased. Lastly, NHD raised the amount of intestinal IAP/LPS, regulated the development of PPAR-α-NPC1L1/SREBP1 pathway in gut-liver axis, and improve lipid metabolism disorder. Our study found that NHD can improve the gut-liver axis metabolic immune crosstalk in model mice caused by excessive drinking. The mechanism might be connected to how NHD controls gut microbiota disorders in model mice, the activation of intestinal SCFAs-GPR41/43 pathway, the remodeling of Th17/Treg immune homeostasis of intestinal CD4+T cells, the improvement of IAP/LPS abnormality, and further mediating the PPAR-α-NPC1L1/SREBP1 pathway of lipid metabolism in gut-liver axis.

Therapeutic microbiome modulation: new frontiers in HIV treatment.

Dysbiosis may be a key driver of systemic inflammation, which increases the risk of non-AIDS events in people living with HIV (PLWH). Modulation of the microbiome to reverse this dysbiosis may be a novel approach to decrease inflammation and therefore morbidity and mortality in PLWH. Fecal microbiota transplantation (FMT), probiotics, prebiotics, synbiotics, postbiotics, and dietary modifications have the potential to modulate the microbiome. These interventions have been well tolerated in clinical trials to date. However, these interventions have not resulted in consistent or lasting changes to the microbiome or consistent changes in biomarkers of intestinal permeability, microbial translocation, inflammation, immune activation, or CD4 + T cell counts. Sustained engraftment may require prebiotics and/or dietary modifications added to either probiotics or FMT. Adequately powered randomized controlled trials are needed to elucidate whether microbiome modulation can be achieved and impact systemic inflammation in PLWH.

CD4+ T Cell Effector Status Is Dependent on Aryl Hydrocarbon Receptor Activation during High Salt Diet

Recent studies suggest that patients with hypertension and individuals that consume a HSD are depleted of numerous tryptophan-derived indoles and other AHR-binding metabolites that are key in intestinal CD4+ T cell homeostasis. Thus, the inappropriate immunologic response by CD4+ T cells, and their role in hypertension, may be due in part to loss of AHR activation. Therefore, we hypothesized that AHR activation contributes to maintaining effector T cell status in salt-sensitive mice. To examine the influence of a representative homeostatic or proinflammatory environment and the subsequent response to salt, we cultured naïve CD4+ T cells under homeostatic cytokine or pathogenic cytokine conditions and exposed the cultures to increased NaCl conditions with or without the AHR-activating metabolite, FICZ (6-Formylindolo(3,2-b)-carbazole). TH17 cells cultured under homeostatic high salt conditions were depressed with a concomitant increase in response to FICZ. In contrast, TH17 cells cultured under pathogenic high salt conditions had augmented IL-17A-expressing cells without a response to AHR activation. These data suggest that excess salt is disrupting the ability to induce IL-17A and increasing AHR activity overcomes this disruption to promote IL-17A, without expansion of the pathogenic TH17 pool, and this observation was specific to non-pathogenic microenvironments (homeostatic TH17: media: 11±0.6%, +NaCl: 4.9±0.3%*, +NaCl/FICZ: 9.9±0.8%, of CD4; pathogenic TH17: media: 1.0±0.2%, +NaCl: 2.2±0.2%*, +NaCl/FICZ: 2.2±0.2%*, *vs respective media, n=8/group). Given these data, we then fed salt-sensitive mice (nitric oxide synthase inhibition) a HSD or a HSD supplemented with the AHR agonist indole-3-carbinol (I3C) and examined Peyer’s patches, a lymphoid tissue in close proximity to intestinal lumen contents enriched with salt and the I3C-metabolites and noted expansion of non-pathogenic TH17 cells. In conclusion, increasing AHR ligand availability through supplementing I3C may provide a gut-centric experimental approach in targeting experimental salt-sensitivity as it relates to immunologic disturbances. F31HL151264. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Unraveling the early transcriptional signature of peripheral blood NK cell transition to uterine residency

Abstract Tissue-resident uterine NK cells are essential for successful pregnancy, yet the molecular mechanisms guiding their tissue residency programming early after infiltration of blood-based precursors remain unknown. We examined the transition of CD56+ peripheral blood NK cells to a uterine resident state by performing scRNA-seq on enriched CD56+ cells from a matched peripheral blood (pb) and endometrial (e) biopsy taken during the secretory phase. Our integrated analysis comparing eNK vs pbNK cells identified a tissue adaptation signature. Key components of this signature included NR4A2 (94% vs 0%, p=9.46e-22), FOS (90% vs 9%, p=9.05e-14), and JUNB (77% vs 16%, p=3.15e-07) respectively. This signature also mirrored genes previously identified in activated murine intestinal CD8+ TRM cells early after LCMV infection. This signature was found in all endometrial CD56+ cells, including CD56bright CD16- eNKs, NKTs, and conventional eNKs (CD56dimCD16+). Pathway analysis implicated IL-17 and IL-18 cytokines, along with NFAT and VEGF signals in tissue residency programming. In conclusion, these data expand our understanding of early transcriptional programs in lymphocyte tissue adaptation, revealing the involvement of cytokines beyond TGF-β. Our data further indicate that signals associated with early tissue adaptation are conserved across species and cell types independent of an antigen receptor.

Probiotic Consortium Confers Synergistic Anti-Inflammatory Effects in Inflammatory Disorders.

The composition and diversity of gut microbiota significantly influence the immune system and are linked to various diseases, including inflammatory and allergy disorders. While considerable research has focused on exploring single bacterial species or consortia, the optimal strategies for microbiota-based therapeutics remain underexplored. Specifically, the comparative effectiveness of bacterial consortia versus individual species warrants further investigation. In our study, we assessed the impact of the bacterial consortium MPRO, comprising Lactiplantibacillus plantarum HY7712, Bifidobacterium animalis ssp. lactis HY8002, and Lacticaseibacillus casei HY2782, in comparison to its individual components. The administration of MPRO demonstrated enhanced therapeutic efficacy in experimental models of atopic dermatitis and inflammatory colitis when compared to single strains. MPRO exhibited the ability to dampen inflammatory responses and alter the gut microbial landscape significantly. Notably, MPRO administration led to an increase in intestinal CD103+CD11b+ dendritic cells, promoting the induction of regulatory T cells and the robust suppression of inflammation in experimental disease settings. Our findings advocate the preference for bacterial consortia over single strains in the treatment of inflammatory disorders, carrying potential clinical relevance.

Hyperactivation and enhanced cytotoxicity of reduced CD8+ gamma delta T cells in the intestine of patients with Crohn’s disease correlates with disease activity

Background and aimsWe aimed to investigate the immune characteristics of intestinal CD8+ gamma delta T (CD8+ γδ T) cells in Crohn’s disease (CD) and their correlation with disease activity.MethodsThe study cohorts included 21 CD patients and 21 healthy individuals. CD8+ γδ T cells were isolated from human ileal mucosa for detection by flow cytometry. The activation or inhibition status of cells was detected by detecting the expression of activation marker HLA-DR and the immunosuppressive molecule PD-1 on cells. The cytotoxicity of cells was assessed by detecting the expression of cytotoxic molecules (Perforin, Granzyme B, and TRAIL) in cells. Ratios of investigated cells were calculated as prediction factors by receiver operating characteristic curve (ROC) analysis.ResultsThe study revealed a reduction in intestinal CD8+ γδT cells among active CD patients, with a more pronounced reduction observed in moderately active patients compared to mildly active patients. Moreover, active CD patients exhibited heightened activation levels in their intestinal CD8+ γδT cells, whereas the activation was comparatively weakened in moderately active patients compared with mildly active patients. Additionally, the cytotoxicity of intestinal CD8+ γδT cells was enhanced solely in mildly active patients, while it was impaired in moderately active patients compared with mildly active patients. Furthermore, HLA-DR+ CD8+ γδT cell ratio, CD8+ γδT ratio, and CD8+ γδT count were identified as indicators in the diagnosis of active CD. Meanwhile, the ratios of Granzyme B+ CD8+ γδT cell and Perforin+ CD8+ γδT cell were identified as indicators that distinguish mildly moderately active CD cases.ConclusionsIntestinal CD8+ γδT was reduced in active CD patients, but their activation and cytotoxicity were enhanced. However, with increased disease activity, intestinal CD8+ γδ T cells became dysfunctional. CD-specific perturbations observed in various phenotypic markers in CD8+ γδ T cells can be used as indicators to assist in diagnosing CD patients.

GRANZYME A-PRODUCING CD4 T CELLS ARE DRIVERS OF IMMUNE CHECKPOINT BLOCKADE-INDUCED COLITIS

Abstract Immune checkpoint blockade (ICB) (i.e. anti-CTLA4 and/or anti-PD-1) is a type of cancer immunotherapy that is broadly and effectively used across multiple cancer types. Despite this efficacy, ~60% of individuals of ICB recipients develop autoimmune-like inflammation in the skin, lungs and intestines. Of these barrier sites, an inflamed intestine is the most common form of severe disease that requires cessation of immunotherapy and potential tumor rebound. ICB-induced colitis therefore represents a significant health concern in an increasing population of cancer patients receiving this otherwise effective immunotherapy. Previous work has shown evidence of a dysregulated intestinal CD4 T cell response in ICB colitis patients, however, how CD4 T cells might contribute to disease has remained unclear. Here, we identify a unique subset of T helper (Th) 1-like CD4 T cells that express the serine protease granzyme A (GZMA) that are specifically elevated in ICB-induced colitis patients, suggesting a pathogenic role for GZMA-expressing Th cells in disease. As mouse models for ICB-induced colitis are virtually non-existent, we have profiled existing mouse models of intestinal inflammation for the presence of colonic GZMA-expressing CD4 T cells for more in-depth functional studies. Using this approach, we have identified the T cell transfer model of colitis as a model that mimics the GZMA CD4 T cell phenotype observed in human ICB colitis patients. Within this model, GZMA-expressing CD4 T cells arise early in the intestines after transfer and only minimally express other CD4 T helper (Th) cell lineage cytokines (i.e. IFN-γ or IL-17) indicating that these cells may represent a unique Th cell subtype that are associated with intestinal disease. Indeed, transfer of GZMA-deficient CD4 T cells into colitis-prone mice resulted in reduced intestinal inflammation and damage, despite efficient trafficking of these cells to the intestines. Mechanistically, CD4 T cell-derived GZMA promoted an exaggerated intestinal epithelial cell response to the microbiota, but was not required for immune-editing of the microbiota in this setting. Taken together, our data indicate that GZMA-producing Th cells are likely major contributors to ICB-induced colitis and may represent a valuable therapeutic target for limiting intestinal disease during ICB therapy.

Prostaglandin E2 controls the metabolic adaptation of T cells to the intestinal microenvironment

Immune cells must adapt to different environments during the course of an immune response. Here we study the adaptation of CD8+ T cells to the intestinal microenvironment and how this process shapes the establishment of the CD8+ T cell pool. CD8+ T cells progressively remodel their transcriptome and surface phenotype as they enter the gut wall, and downregulate expression of mitochondrial genes. Human and mouse intestinal CD8+ T cells have reduced mitochondrial mass, but maintain a viable energy balance to sustain their function. We find that the intestinal microenvironment is rich in prostaglandin E2 (PGE2), which drives mitochondrial depolarization in CD8+ T cells. Consequently, these cells engage autophagy to clear depolarized mitochondria, and enhance glutathione synthesis to scavenge reactive oxygen species (ROS) that result from mitochondrial depolarization. Impairing PGE2 sensing promotes CD8+ T cell accumulation in the gut, while tampering with autophagy and glutathione negatively impacts the T cell pool. Thus, a PGE2-autophagy-glutathione axis defines the metabolic adaptation of CD8+ T cells to the intestinal microenvironment, to ultimately influence the T cell pool.

B cell-mediated CD4 T-cell costimulation via CD86 exacerbates pro-inflammatory cytokine production during autoimmune intestinal inflammation

Dysregulated B cell responses have been described in inflammatory-bowel disease (IBD) patients; however, the role of B cells in IBD pathology remained incompletely understood. We here provide evidence for a detrimental role of activated B cells during the onset of autoimmune intestinal inflammation. Using Wiskott-Aldrich Syndrome interacting protein deficient (Wipf1-/-) mice as a mouse model of chronic colitis, we identified CD86 expression on activated B cells as a crucial factor exacerbating pro-inflammatory cytokine production of intestinal CD4 T cells. Depleting B cells through anti-CD20 antibody treatment or blocking co-stimulatory signals mediated by CD86 through CTLA-4-Ig diminished intestinal inflammation in our mouse model of chronic IBD at the onset of disease. This was due to a reduction in aberrant humoral immune responses and reduced CD4 T cell pro-inflammatory cytokine production, especially IFN-γ and GM-CSF. Interestingly, in addition to B cells isolated from the inflamed colon of Wipf1-/- mice, we also found CD86 mRNA and protein expression up-regulated on activated B cells isolated from inflamed tissue of human IBD patients. B cell activation and CD86 expression was boosted by soluble CD40L in vitro, which we found in the serum of mice and human IBD patients. In summary, our data provides detailed insight into the contribution of B cells to intestinal inflammation, with implications for the treatment of IBD.

A tryptophan metabolite made by a gut microbiome eukaryote induces pro-inflammatory T cells.

The large intestine harbors microorganisms playing unique roles in host physiology. The beneficial or detrimental outcome of host-microbiome coexistence depends largely on the balance between regulators and responder intestinal CD4+ T cells. We found that ulcerative colitis-like changes in the large intestine after infection with the protist Blastocystis ST7 in a mouse model are associated with reduction of anti-inflammatory Treg cells and simultaneous expansion of pro-inflammatory Th17 responders. These alterations in CD4+ T cells depended on the tryptophan metabolite indole-3-acetaldehyde (I3AA) produced by this single-cell eukaryote. I3AA reduced the Treg subset in vivo and iTreg development in vitro bymodifying their sensing of TGFβ, concomitantly affecting recognition of self-flora antigens by conventional CD4+ T cells. Parasite-derived I3AA also induces over-exuberant TCR signaling, manifested by increased CD69 expression and downregulation of co-inhibitor PD-1. We have thus identified a new mechanism dictating CD4+ fate decisions. The findings thus shine a new light on the ability of the protist microbiome and tryptophan metabolites, derived from them or other sources, to modulate the adaptive immune compartment, particularly in the context of gut inflammatory disorders.

Screening single-cell trajectories via continuity assessments for cell transition potential.

Advances in single-cell sequencing and data analysis have made it possible to infer biological trajectories spanning heterogeneous cell populations based on transcriptome variation. These trajectories yield a wealth of novel insights into dynamic processes such as development and differentiation. However, trajectory analysis relies on an assumption of trajectory continuity, and experimental limitations preclude some real-world scenarios from meeting this condition. The current lack of assessment metrics makes it difficult to ascertain if/when a given trajectory deviates from continuity, and what impact such a divergence would have on inference accuracy is unclear. By analyzing simulated breaks introduced into in silico and real single-cell data, we found that discontinuity caused precipitous drops in the accuracy of trajectory inference. We then generate a simple scoring algorithm for assessing trajectory continuity, and found that continuity assessments in real-world cases of intestinal stem cell development and CD8 + T cells differentiation efficiently identifies trajectories consistent with empirical knowledge. This assessment approach can also be used in cases where a priori knowledge is lacking to screen a pool of inferred lineages for their adherence to presumed continuity, and serve as a means for weighing higher likelihood trajectories for validation via empirical studies, as exemplified by our case studies in psoriatic arthritis and acute kidney injury. This tool is freely available through github at qingshanni/scEGRET.

Maternal polysorbate 80 exposure causes intestinal ILCs and CD4+ T cell developmental abnormalities in mouse offspring

This study aimed to investigate the transgenerational impacts of maternal intake of polysorbate 80 (P80), an emulsifier widely used in modern society, on the development of offspring immunity. Our results revealed that maternal P80 treatment led to impaired differentiation of innate lymphoid cells (ILCs) and CD4+ T cells in the small intestinal lamina propria (SiLP), resulting in intestinal dyshomeostasis in female offspring. Furthermore, we found that SiLP ILCs abundances were significantly altered in 0-day-old fetuses from P80-treated mothers, indicating a prenatal impact of P80-treated mothers on offspring immunity. Additionally, cesarean section and foster-nursing studies demonstrated that P80-induced altered SiLP ILCs in 0-day-old fetuses could further induce dysregulation of ILCs and CD4+ T cells in the SiLP, thus promoting intestinal dysregulation in offspring later in life. Overall, our findings suggest that maternal P80 intake could prenatally program the development of offspring immunity, exerting a significant and long-lasting impact.

Compartment-driven imprinting of intestinal CD4 T cells in inflammatory bowel disease and homeostasis.

The mucosal immune system is implicated in the etiology and progression of inflammatory bowel diseases. The lamina propria and epithelium of the gut mucosa constitute two separate compartments, containing distinct T-cell populations. Human CD4 T-cell programming and regulation of lamina propria and epithelium CD4 T cells, especially during inflammation, remain incompletely understood. We performed flow cytometry, bulk, and single-cell RNA-sequencing to profile ileal lamina propria and intraepithelial CD4 T cells (CD4CD8αα, regulatory T cells (Tregs), CD69- and CD69high Trm T cells) in controls and Crohn's disease (CD) patients (paired non-inflamed and inflamed). Inflammation results in alterations of the CD4 T-cell population with a pronounced increase in Tregs and migrating/infiltrating cells. On a transcriptional level, inflammation within the epithelium induced T-cell activation, increased IFNγ responses, and an effector Treg profile. Conversely, few transcriptional changes within the lamina propria were observed. Key regulators including the chromatin remodelers ARID4B and SATB1 were found to drive compartment-specific transcriptional programming of CD4 T(reg) cells. In summary, inflammation in CD patients primarily induces changes within the epithelium and not the lamina propria. Additionally, there is compartment-specific CD4 T-cell imprinting, driven by shared regulators, between the lamina propria and the epithelium. The main consequence of intraepithelial adaptation, irrespective of inflammation, seems to be an overall dampening of broad (pro-inflammatory) responses and tight regulation of lifespan. These data suggest differential regulation of the lamina propria and epithelium, with a specific regulatory role in the inflamed epithelium.

The chromatin and single-cell transcriptional landscapes of CD4 T cells in inflammatory bowel disease link risk loci with a proinflammatory Th17 cell population.

The imbalance between Th17 and regulatory T cells in inflammatory bowel diseases (IBD) promotes intestinal epithelial cell damage. In this scenario, T helper cell lineage commitment is accompanied by dynamic changes to the chromatin that facilitate or repress gene expression. Here, we characterized the chromatin landscape and heterogeneity of intestinal and peripheral CD4 T cellsfrom IBD patients using in house ATAC-Seq and single cell RNA-Seq libraries. We show that chromatin accessibility profiles of CD4 T cells from inflamed intestinal biopsies relate to genes associated with a network of inflammatory processes. After integrating the chromatin profiles of tissue-derived CD4 T cells and in-vitro polarized CD4 T cell subpopulations, we found that the chromatin accessibility changes of CD4 T cells were associated with a higher predominance of pathogenic Th17 cells (pTh17 cells) in inflamed biopsies. In addition, IBD risk loci in CD4 T cells were colocalized with accessible chromatin changes near pTh17-related genes, as shown in intronic STAT3 and IL23R regions enriched in areas of active intestinal inflammation. Moreover, single cell RNA-Seq analysis revealed a population of pTh17 cells that co-expresses Th1 and cytotoxic transcriptional programs associated with IBD severity. Altogether, we show that cytotoxic pTh17 cells were specifically associated with IBD genetic variants and linked to intestinal inflammation of IBD patients.

Glycolytic Activation of CD14+ Intestinal Macrophages Contributes to the Inflammatory Responses via Exosomal Membrane Tumor Necrosis Factor in Crohn's Disease.

Macrophage (Mφ) activation plays a critical role in the inflammatory response. Activated Mφ go through profound reprogramming of cellular metabolism. However, changes in their intracellular energy metabolism and its effect on inflammatory responses in Crohn's disease (CD) remain currently unclear. The aim of this study is to explore metabolic signatures of CD14+ Mφ and their potential role in CD pathogenesis as well as the underlying mechanisms. CD14+ Mφ were isolated from peripheral blood or intestinal tissues of CD patients and control subjects. Real-time flux measurements and enzyme-linked immunosorbent assay were used to determine the inflammatory states of Mφ and metabolic signatures. Multiple metabolic routes were suppressed to determine their relevance to cytokine production. Intestinal CD14+ Mφ in CD patients exhibited activated glycolysis compared with those in control patients. Specifically, macrophagic glycolysis in CD largely induced inflammatory cytokine release. The intestinal inflammatory microenvironment in CD elicited abnormal glycolysis in Mφ. Mechanistically, CD14+ Mφ derived exosomes expressed membrane tumor necrosis factor (TNF), which engaged TNFR2 and triggered glycolytic activation via TNF/nuclear factor κB autocrine and paracrine signaling. Importantly, clinically applicable anti-TNF antibodies effectively prevented exosomal membrane TNF-induced glycolytic activation in CD14+ Mφ. CD14+ Mφ take part in CD pathogenesis by inducing glycolytic activation via membrane TNF-mediated exosomal autocrine and paracrine signaling. These results provide novel insights into pathogenesis of CD and enhance understanding of the mechanisms of anti-TNF agents.

Comprehensive Analysis of the miRNA-mRNA Pathological Regulatory Network of Intestinal CD4 + T Cells in Parkinson's Disease.

Infiltration of CD4 + T cells was found in brain tissue samples from PD patients, suggesting their involvement in developing central nervous system (CNS) disease. The idea of the gut-brain axis further corroborates intestinal T cells' activation as the central immune response initiation. However, the specific factors and molecular pathways regulating intestinal T-cell activation are unclear. We used the GSE156287 and GSE145814 datasets from the GEO database to analyze and obtain the miRNAs, which are aberrantly expressed in intestinal CD4 + T cells in PD patients and predict their regulatory target mRNAs. Further, combined with the GSE174473 dataset of CD4 + T cells sequencing in PD patients, we finally clarified the aberrant genes expressed in CD4 + T cells from the intestine of PD patients and constructed a miRNA-mRNA regulatory network. The highlight of our findings showed pathways, networks, biological functions, and key molecules potentially involved in the miRNA-mediated functional effects in CD4 + T cell from the intestine of PD patients. The hsa-miR-3180-3p mediated CBX8, etc. were determined as most effective in enhancing T cell survival. PEG10, etc. regulated by hsa-miR-20a-3p targets were possibly involved in T cell differentiation. The JPT2 regulated by hsa-miR-1281 were involved in influencing T cell infiltration. The discovery of this interaction between miRNA and mRNA in CD4 + T cell has important implications for understanding the intestinal initial of PD pathological molecular and anti-inflammation of T cell activation.

Hypomethylation and Overexpression of Th17-Associated Genes is a Hallmark of Intestinal CD4+ Lymphocytes in Crohn's Disease.

The development of Crohn's disease [CD] involves immune cell signalling pathways regulated by epigenetic modifications. Aberrant DNA methylation has been identified in peripheral blood and bulk intestinal tissue from CD patients. However, the DNA methylome of disease-associated intestinal CD4+ lymphocytes has not been evaluated. Genome-wide DNA methylation sequencing was performed from terminal ileum CD4+ cells from 21 CD patients and 12 age- and sex-matched controls. Data were analysed for differentially methylated CpGs [DMCs] and methylated regions [DMRs]. Integration was performed with RNA-sequencing data to evaluate the functional impact of DNA methylation changes on gene expression. DMRs were overlapped with regions of differentially open chromatin [by ATAC-seq] and CCCTC-binding factor [CTCF] binding sites [by ChIP-seq] between peripherally derived Th17 and Treg cells. CD4+ cells in CD patients had significantly increased DNA methylation compared to those from the controls. A total of 119 051 DMCs and 8113 DMRs were detected. While hypermethylated genes were mostly related to cell metabolism and homeostasis, hypomethylated genes were significantly enriched within the Th17 signalling pathway. The differentially enriched ATAC regions in Th17 cells [compared to Tregs] were hypomethylated in CD patients, suggesting heightened Th17 activity. There was significant overlap between hypomethylated DNA regions and CTCF-associated binding sites. The methylome of CD patients shows an overall dominant hypermethylation yet hypomethylation is more concentrated in proinflammatory pathways, including Th17 differentiation. Hypomethylation of Th17-related genes associated with areas of open chromatin and CTCF binding sites constitutes a hallmark of CD-associated intestinal CD4+ cells.

Dietary protein shapes the profile and repertoire of intestinal CD4+ T cells.

The intestinal immune system must tolerate food antigens to avoid allergy, a process requiring CD4+ T cells. Combining antigenically defined diets with gnotobiotic models, we show that food and microbiota distinctly influence the profile and T cell receptor repertoire of intestinal CD4+ T cells. Independent of the microbiota, dietary proteins contributed to accumulation and clonal selection of antigen-experienced CD4+ T cells at the intestinal epithelium, imprinting a tissue-specialized transcriptional program including cytotoxic genes on both conventional and regulatory CD4+ T cells (Tregs). This steady state CD4+ T cell response to food was disrupted by inflammatory challenge, and protection against food allergy in this context was associated with Treg clonal expansion and decreased proinflammatory gene expression. Finally, we identified both steady-state epithelium-adapted CD4+ T cells and tolerance-induced Tregs that recognize dietary antigens, suggesting that both cell types may be critical for preventing inappropriate immune responses to food.