Crosstalk between CD8+ T cells and mesenchymal stromal cells in intestine homeostasis and immunity.

The intestine represents the most complex cellular network in the whole body. It is constantly faced with multiple types of immunostimulatory agents encompassing from food antigen, gut microbiome, metabolic waste products, and dead cell debris. Within the intestine, most T cells are found in three primary compartments: the organized gut-associated lymphoid tissue, the lamina propria, and the epithelium. The well-orchestrated epithelial-immune-microbial interaction is critically important for the precise immune response. The main role of intestinal mesenchymal stromal cells is to support a structural framework within the gut wall. However, recent evidence from stromal cell studies indicates that they also possess significant immunomodulatory functions, such as maintaining intestinal tolerance via the expression of PDL1/2 and MHC-II molecules, and promoting the development of CD103+ dendritic cells, and IgA+ plasma cells, thereby enhancing intestinal homeostasis. In this review, we will summarize the current understanding of CD8+ T cells and stromal cells alongside the intestinal tract and discuss the reciprocal interactions between T subsets and mesenchymal stromal cell populations. We will focus on how the tissue residency, migration, and function of CD8+ T cells could be potentially regulated by mesenchymal stromal cell populations and explore the molecular mediators, such as TGF-ß, IL-33, and MHC-II molecules that might influence these processes. Finally, we discuss the potential pathophysiological impact of such interaction in intestine hemostasis as well as diseases of inflammation, infection, and malignancies.

Acoustic Metagrating Holograms.

Metasurface holograms represent a common category of metasurface devices that utilize in-plane phase gradients to shape wavefronts, forming holographic images through the application of the generalized Snell's law (GSL). While conventional metasurfaces focus solely on phase gradients, metagratings, which incorporate higher-order wave diffraction, further expand the GSL's generality. Recent advances in certain acoustic metagratings demonstrate an updated GSL extension capable of reversing anomalous transmission and reflection, whose reversal is characterized by the parity of the number of wave propagation trips through the metagrating. However, the current extension of GSL remains limited to 1D metagratings, unable to access 2D holographic images in 3D spaces. Here, the GSL extension to 2D metagratings for manipulating waves within 3D spaces is investigated. Through this analysis, a series of acoustic metagrating holograms is experimentally demonstrated. These holographic images exhibit the unique ability to switch between transmission and reflection types independently. This study introduces an additional dimension to modern holography design and metasurface wavefront manipulation.

DEPDC5 protects CD8+ T cells from ferroptosis by limiting mTORC1-mediated purine catabolism.

Peripheral CD8+ T cell number is tightly controlled but the precise molecular mechanism regulating this process is still not fully understood. In this study, we found that epilepsy patients with loss of function mutation of DEPDC5 had reduced peripheral CD8+ T cells, and DEPDC5 expression positively correlated with tumor-infiltrating CD8+ T cells as well as overall cancer patient survival, indicating that DEPDC5 may control peripheral CD8+ T cell homeostasis. Significantly, mice with T cell-specific Depdc5 deletion also had reduced peripheral CD8+ T cells and impaired anti-tumor immunity. Mechanistically, Depdc5-deficient CD8+ T cells produced high levels of xanthine oxidase and lipid ROS due to hyper-mTORC1-induced expression of ATF4, leading to spontaneous ferroptosis. Together, our study links DEPDC5-mediated mTORC1 signaling with CD8+ T cell protection from ferroptosis, thereby revealing a novel strategy for enhancing anti-tumor immunity via suppression of ferroptosis.

Observation of vortex-string chiral modes in metamaterials.

As hypothetical topological defects in the geometry of spacetime, vortex strings could have played many roles in cosmology, and their distinct features can provide observable clues about the early universe's evolution. A key feature of vortex strings is that they can interact with Weyl fermionic modes and support massless chiral-anomaly states along strings. To date, despite many attempts to detect vortex strings in astrophysics or to emulate them in artificially created systems, observation of these vortex-string chiral modes remains experimentally elusive. Here we report experimental observations of vortex-string chiral modes using a metamaterial system. This is implemented by inhomogeneous perturbation of Yang-monopole phononic metamaterials. The measured linear dispersion and modal profiles confirm the existence of topological modes bound to and propagating along the string with the chiral anomaly. Our work provides a platform for studying diverse cosmic topological defects in astrophysics and offers applications as topological fibres in communication techniques.

Three-dimensional flat Landau levels in an inhomogeneous acoustic crystal.

When electrons moving in two dimensions (2D) are subjected to a strong uniform magnetic field, they form flat bands called Landau levels (LLs). LLs can also arise from pseudomagnetic fields (PMFs) induced by lattice distortions. In three-dimensional (3D) systems, there has been no experimental demonstration of LLs  as a type of flat band thus far. Here, we report the experimental realization of a flat 3D LL in an acoustic crystal. Starting from a lattice whose bandstructure exhibits a nodal ring, we design an inhomogeneous distortion corresponding to a specific pseudomagnetic vector potential (PVP). This distortion causes the nodal ring states to break up into LLs, including a zeroth LL that is flat along all three directions. These findings suggest the possibility of using nodal ring materials to generate 3D flat bands, allowing access to strong interactions and other attractive physical regimes in 3D.

Integration of Pan-Cancer Single-Cell and Spatial Transcriptomics Reveals Stromal Cell Features and Therapeutic Targets in Tumor Microenvironment.

Stromal cells are physiologically essential components of the tumor microenvironment (TME) that mediates tumor development and therapeutic resistance. Development of a logical and unified system for stromal cell type identification and characterization of corresponding functional properties could help design antitumor strategies that target stromal cells. Here, we performed a pan-cancer analysis of 214,972 nonimmune stromal cells using single-cell RNA sequencing from 258 patients across 16 cancer types and analyzed spatial transcriptomics from 16 patients across seven cancer types, including six patients receiving anti-PD-1 treatment. This analysis uncovered distinct features of 39 stromal subsets across cancer types, including various functional modules, spatial locations, and clinical and therapeutic relevance. Tumor-associated PGF+ endothelial tip cells with elevated epithelial-mesenchymal transition features were enriched in immune-depleted TME and associated with poor prognosis. Fibrogenic and vascular pericytes (PC) derived from FABP4+ progenitors were two distinct tumor-associated PC subpopulations that strongly interacted with PGF+ tips, resulting in excess extracellular matrix (ECM) abundance and dysfunctional vasculature. Importantly, ECM-related cancer-associated fibroblasts enriched at the tumor boundary acted as a barrier to exclude immune cells, interacted with malignant cells to promote tumor progression, and regulated exhausted CD8+ T cells via immune checkpoint ligand-receptors (e.g., LGALS9/TIM-3) to promote immune escape. In addition, an interactive web-based tool (http://www.scpanstroma.yelab.site/) was developed for accessing, visualizing, and analyzing stromal data. Taken together, this study provides a systematic view of the highly heterogeneous stromal populations across cancer types and suggests future avenues for designing therapies to overcome the tumor-promoting functions of stromal cells. SIGNIFICANCE: Comprehensive characterization of tumor-associated nonimmune stromal cells provides a robust resource for dissecting tumor microenvironment complexity and guiding stroma-targeted therapy development across multiple human cancer types.

Mechanism of Innate Immune Response Induced by Albizia julibrissin Saponin Active Fraction Using C2C12 Myoblasts.

Albizia julibrissin saponin active fraction (AJSAF), is a prospective adjuvant with dual Th1/Th2 and Tc1/Tc2 potentiating activity. Its adjuvant activity has previously been proven to be strictly dependent on its spatial co-localization with antigens, highlighting the role of local innate immunity in its mechanisms. However, its potential targets and pathways remain unclear. Here, its intracellular molecular mechanisms of innate immune response were explored using mouse C2C12 myoblast by integrative analysis of the in vivo and in vitro transcriptome in combination with experimental validations. AJSAF elicited a temporary cytotoxicity and inflammation towards C2C12 cells. Gene set enrichment analysis demonstrated that AJSAF regulated similar cell death- and inflammatory response-related genes in vitro and in vivo through activating second messenger-MAPK-CREB pathways. AJSAF markedly enhanced the Ca2+, cAMP, and reactive oxygen species levels and accelerated MAPK and CREB phosphorylation in C2C12 cells. Furthermore, Ca2+ chelator, CREB inhibitor, and MAPK inhibitors dramatically blocked the up-regulation of IL-6, CXCL1, and COX2 in AJSAF-treated C2C12 cells. Collectively, these results demonstrated that AJSAF induced innate immunity via Ca2+-MAPK-CREB pathways. This study is beneficial for insights into the molecular mechanisms of saponin adjuvants.

Structural characterization and adjuvant action of Paulownia tomentosa flower polysaccharide on the immune responses to classical swine fever vaccine in mice.

Paulownia tomentosa flower polysaccharide (PTFP) from dried cultured P. tomentosa flowers, is widely known for its immunomodulatory activities. Here, PTFP was extracted from Paulownia tomentosa flower using hot water extraction, followed by ethanol precipitation methods. Structural characterization of PTFP was revealed by scanning electron microscope, high-performance anion-exchange chromatography, gel chromatography, ultraviolet and infrared spectral. Meanwhile, adjuvant action of PTFT on the immune responses to classical swine fever vaccine in mice was evaluated to further proclaim the immune regulatory effect of PTFP. The results showed that PTFP was a type of heteropolysaccharide with a dense, rough surface and high molecular weight (667.02 kDa), mainly composed of glucose (30.93%), rhamnose (29.99%), galactose (15.66%), arabinose (6.95%), mannose (5.52%), and xylose (4.80%). The results of gel chromatography suggested that the molecular configuration of PTFP may be a spherical structure. The infrared spectrum results confirmed that the functional groups and chemical bond of PTFP contained -OH, O-H, C-H, C=O, C-O, etc. Moreover, PTFP exhibited obvious immune enhancement effect by improving concanavalin A (ConA), lipopolysaccharide (LPS), and CSFV E2-stimulated splenocyte growth and natural killer cell activity in CSFV-immunized mice. Similarly, the titers of CSFV E2-specific IgG, IgG1, IgG2a, and IgG2b antibodies and IFN-γ and IL-10 levels in CSFV-immunized mice were distinctly increased by PTFP treatment. Overall, PTFP was a macromolecular heteropolysaccharide primarily containing glucose and rhamnose, and possessed the auxiliary effect of immune enhancement on the immune responses to classical swine fever vaccine.

Isorhamnetin as a novel inhibitor of pneumolysin against Streptococcus pneumoniae infection in vivo/in vitro.

The increasing incidence of Streptococcus pneumoniae (S. pneumoniae) infection severely threatened the global public heath, causing a significant fatality in immunocompromised hosts. Notably, pneumolysin (PLY) as a pore-forming cytolysin plays a crucial role in the pathogenesis of pneumococcal pneumonia and lung injury. In this study, a natural flavonoid isorhamnetin was identified as a PLY inhibition to suppress PLY-induced hemolysis by engaging the predicted residues and attenuate cytolysin PLY-mediated A549 cells injury. Underlying mechanisms revealed that PLY inhibitor isorhamnetin further contributed to decrease the formation of bacterial biofilms without affecting the expression of PLY. In vivo S. pneumoniae infection confirmed that the pathological injury of lung tissue evoked by S. pneumoniae was ameliorated by isorhamnetin treatment. Collectively, these results presented that isorhamnetin could inhibit the biological activity of PLY, thus reducing the pathogenicity of S. pneumoniae. In summary, our study laid a foundation for the feasible anti-virulence strategy targeting PLY, and provided a promising PLY inhibitor for the treatment of S. pneumoniae infection.

3ß-Hydroxy-12-oleanen-27-oic Acid Exerts an Antiproliferative Effect on Human Colon Carcinoma HCT116 Cells via Targeting FDFT1.

3ß-hydroxy-12-oleanen-27-oic acid (ATA), a cytotoxic oleanane triterpenoid with C14-COOH isolated from the rhizome of Astilbe chinensis, has been previously proven to possess antitumor activity and may be a promising antitumor agent. However, its molecular mechanisms of antitumor action were still unclear. This study explored the underlying mechanisms of cytotoxicity and potential target of ATA against human colorectal cancer HCT116 cells via integrative analysis of transcriptomics and network pharmacology in combination with in vitro and in vivo experimental validations. ATA significantly inhibited the proliferation of HCT116 cells in a concentration- and time-dependent manner and induced the cell cycle arrest at the G0/G1 phase, apoptosis, autophagy, and ferroptosis. Transcriptomic analysis manifested that ATA regulated mRNA expression of the genes related to cell proliferation, cell cycle, and cell death in HCT116 cells. The integrated analysis of transcriptomics, network pharmacology, and molecular docking revealed that ATA exerted cytotoxic activity via interactions with FDFT1, PPARA, and PPARG. Furthermore, FDFT1 was verified to be an upstream key target mediating the antiproliferative effect of ATA against HCT116 cells. Of note, ATA remarkably suppressed the growth of HCT116 xenografts in nude mice and displayed an apparent attenuation of FDFT1 in tumor tissues accompanied by the alteration of the biomarkers of autophagy, cell cycle, apoptosis, and ferroptosis. These results demonstrate that ATA exerted in vitro and in vivo antiproliferative effects against HCT116 cells through inducing cell apoptosis, autophagy, and ferroptosis via targeting FDFT1.

Actinidia eriantha polysaccharide exerts adjuvant activity by targeting linc-AAM.

Actinidia eriantha polysaccharide (AEPS) is a potent adjuvant with dual Th1 and Th2 potentiating activity. linc-AAM has been previously proved to facilitate the expression of immune response genes (IRGs) in AEPS-activated RAW264.7 macrophages. However, its role in mediating adjuvant activity of AEPS remains to be elucidated. In this study, bone marrow-derived macrophages (BMDMs) from wide-type (WT) and linc-AAM knockout C57BL/6J mice treated with AEPS were subjected to transcriptome sequencing and bioinformatic analysis. linc-AAM deficiency inhibited M1 and M2 immune responses in BMDMs induced by AEPS. In mechanisms, AEPS facilitated the expression of IRGs and activated BMDMs through NF-κB-linc-AAM-JAK/STAT axis. Furthermore, linc-AAM knockout inhibited cytokine and chemokine production, immune cell recruitment as well as immune cell migration to draining lymph nodes at peritoneal cavity in mice induced by AEPS. More importantly, linc-AAM deletion reduced the adjuvant activity of APES on antigen-specific cellular and humoral immune responses to ovalbumin in mice. This study has for the first time demonstrated the role of lncRNAs in regulating the adjuvant activity of polysaccharides and its mechanisms. These findings expanded current knowledge on the mechanism of action of adjuvant and provide a new target for the design and development of vaccine adjuvants.

Regulation of CD8+ T memory and exhaustion by the mTOR signals.

CD8+ T cells are the key executioners of the adaptive immune arm, which mediates antitumor and antiviral immunity. Naïve CD8+ T cells develop in the thymus and are quickly activated in the periphery after encountering a cognate antigen, which induces these cells to proliferate and differentiate into effector cells that fight the initial infection. Simultaneously, a fraction of these cells become long-lived memory CD8+ T cells that combat future infections. Notably, the generation and maintenance of memory cells is profoundly affected by various in vivo conditions, such as the mode of primary activation (e.g., acute vs. chronic immunization) or fluctuations in host metabolic, inflammatory, or aging factors. Therefore, many T cells may be lost or become exhausted and no longer functional. Complicated intracellular signaling pathways, transcription factors, epigenetic modifications, and metabolic processes are involved in this process. Therefore, understanding the cellular and molecular basis for the generation and fate of memory and exhausted CD8+ cells is central for harnessing cellular immunity. In this review, we focus on mammalian target of rapamycin (mTOR), particularly signaling mediated by mTOR complex (mTORC) 2 in memory and exhausted CD8+ T cells at the molecular level.

Anti-tumor effect of Crocus sativus petals polysaccharides by reconstructing tumor microenvironment.

Two polysaccharides from Crocus sativus petals (PCSPs), PCSPA and PCSPB have been previously reported to possess the immunopotentiation activity and improve innate immunity in mice. In this study, PCSPB was evaluated for the anti-tumor activity and explored its immunological mechanisms based on tumor microenvironment (TME) using S180 sarcoma-bearing mice. Although PCSPB showed the lower toxicity to a series of tumor cells, it significantly and dose-dependently suppressed the growth of S180 sarcomas transplanted in mice. HE staining, immunohistochemical analysis, and TUNEL assay revealed that PCSPB significantly induced tumor cell necrosis, apoptosis, and vessel disruption in sarcoma tissues. Meanwhile, PCSPB markedly decreased the levels of inflammatory factors TGF-ß, IFN-γ, IL-10 and TNF-α and down-regulated the mRNA expression levels of TGF-ß and TNF-α in tumor tissues. Flow cytometric analysis showed that PCSPB significantly increased the proportion of CD8+ T cells and NK cells, but decreased that of regulatory T cells (Tregs), total myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs) in sarcoma tissues. Furthermore, immunofluorescence assay demonstrated that PCSPB noteworthily reprogrammed TAMs from a tumorigenic M2 towards an antitumorigenic M1 phenotype in S180 tissues. These findings demonstrated that PCSPB might exert the anti-tumor activity by reconstructing TME and could act as an anti-tumor candidate with low toxicity.

A novel reporter mouse line for studying alveolar macrophages.

Alveolar macrophages (AMs) are self-maintained immune cells that play vital roles in lung homeostasis and immunity. Although reporter mice and culture systems have been established for studying macrophages, an accurate and specific reporter line for alveolar macrophage study is still not available. Here we reported a novel Rspo1-tdTomato gene reporter mouse line that could specifically label mouse AMs in a cell-intrinsic manner. Using this reporter system, we visualized the dynamics of alveolar macrophages intravitally under steady state and characterized the alveolar macrophage differentiation under in vitro condition. By performing ATAC-seq, we found that insertion of the tdTomato cassette in the Rspo1 locus increased the accessibility of a PPARE motif within the Rspo1 locus and revealed a potential regulation by key transcription factor PPAR-γ for alveolar macrophage differentiation in vitro and in vivo. Consistently, perturbation of PPAR-γ by its agonist rosiglitazone or inhibitor GW9662 resulted in corresponding alteration of tdTomato expression in alveolar macrophages together with the transcription of PPAR-γ downstream target genes. Furthermore, global transcriptomic analyses of AMs from the wild type mice and the Rspo1-tdTomato mice showed comparable gene expression profiles, especially those AM-specific genes, confirming that the insertion of the tdTomato cassette in the Rspo1 locus does not impact the cell identity and biological function of AMs under normal condition. Taken together, our study provides an alternative tool for in vivo and in vitro labeling of alveolar macrophages with high specificity which could also be utilized as an indicator of PPAR-γ activity for future development of PPAR-γ specific targeting drugs.

Adjuvant activity of tubeimosides by mediating the local immune microenvironment.

Rhizoma Bolbostemmatis, the dry tuber of Bolbostemma paniculatum, has being used for the treatment of acute mastitis and tumors in traditional Chinese medicine. In this study, tubeimoside (TBM) I, II, and III from this drug were investigated for the adjuvant activities, structure-activity relationships (SAR), and mechanisms of action. Three TBMs significantly boosted the antigen-specific humoral and cellular immune responses and elicited both Th1/Th2 and Tc1/Tc2 responses towards ovalbumin (OVA) in mice. TBM I also remarkably facilitated mRNA and protein expression of various chemokines and cytokines in the local muscle tissues. Flow cytometry revealed that TBM I promoted the recruitment and antigen uptake of immune cells in the injected muscles, and augmented the migration and antigen transport of immune cells to the draining lymph nodes. Gene expression microarray analysis manifested that TBM I modulated immune, chemotaxis, and inflammation-related genes. The integrated analysis of network pharmacology, transcriptomics, and molecular docking predicted that TBM I exerted adjuvant activity by interaction with SYK and LYN. Further investigation verified that SYK-STAT3 signaling axis was involved in the TBM I-induced inflammatory response in the C2C12 cells. Our results for the first time demonstrated that TBMs might be promising vaccine adjuvant candidates and exert the adjuvant activity through mediating the local immune microenvironment. SAR information contributes to developing the semisynthetic saponin derivatives with adjuvant activities.

Herba Origani alleviated DSS-induced ulcerative colitis in mice through remolding gut microbiota to regulate bile acid and short-chain fatty acid metabolisms.

This study aimed to investigate the protective effect of Herba Origani, the dried whole herb of Origanum vulgare L., on dextran sodium sulfate (DSS)-induced ulcerative colitis in mice and explore its mechanisms of action through analyzing the intestinal microbiota in cecum contents and metabolites in colonic tissues. HOEP alleviated colitis symptoms, colonic inflammation and pathological injury as well as repaired intestinal barrier function in DSS-induced UC mice. The intestinal microbiota analysis showed that HOEP restored the gut microbiota dysbiosis in DSS-treated mice by increasing the alpha diversity of the intestinal microbiota, increasing the abundance of the Bacteroidota community and adjusting short-chain fatty acids (SCFAs), which maintain mucosal immunity and intestinal barrier. Metabolomic analysis revealed that HOEP promoted bile acids absorption and regulated bile acids metabolism in the intestine, thereby maintaining intestinal mucosal immune homeostasis. In addition, HOEP might also regulate the intestinal immune system through the phosphatidylinositol signaling system. These findings suggested that HOEP exerted promising protection against DSS-induced ulcerative mice through remolding gut microbiota to regulate bile acid and SCFA metabolism, and that HOEP have a potential to be utilized for the treatment of inflammatory intestinal diseases.

Spinful Topological Phases in Acoustic Crystals with Projective PT Symmetry.

For the classification of topological phases of matter, an important consideration is whether a system is spinless or spinful, as these two classes have distinct symmetry algebra that gives rise to fundamentally different topological phases. However, only recently has it been realized theoretically that in the presence of gauge symmetry, the algebraic structure of symmetries can be projectively represented, which possibly enables the switch between spinless and spinful topological phases. Here, we report the experimental demonstration of this idea by realizing spinful topological phases in "spinless" acoustic crystals with projective space-time inversion symmetry. In particular, we realize a one-dimensional topologically gapped phase characterized by a 2Z winding number, which features double-degenerate bands in the entire Brillouin zone and two pairs of degenerate topological boundary modes. Our Letter thus overcomes a fundamental constraint on topological phases by spin classes.

scRNA-seq profiling of neonatal and adult thymus-derived CD4+ T cells by a T cell origin-time tracing model.

It is well documented that the neonatal thymus-derived (neonatal-TD) regulatory T cells (Treg) are essential to prevent lethal autoimmune diseases and allergies, and neonatal and adult thymus possesses distinct output potentials for naïve T cells, including Treg. However, the molecular features and detailed functional differences between neonatal-TD and adult thymus-derived (adult-TD) T cells in terms of their ability to maintain immune homeostasis during long-term environmental influences are still largely unknown, partially due to the lack of appropriate animal models to precisely trace these cells at specific time points. In this study, neonatal-TD and adult-TD CD4+ T cells from the spleen and Peyer's patches were traced for 9 weeks by a T cell origin-time tracing mouse model and analysed by single-cell RNA sequencing. More Treg but fewer naïve T cells were found in neonatal-TD CD4+ T cells from both tissues than those from adult-TD counterparts. Interestingly, the neonatal-TD Treg in both the spleen and Peyer's patches exhibited augmented expression of Foxp3, Gata3, Ctla4, Icos, Il2ra, Tgfb1, and Nrp1, as well as enriched Gene Ontology terms like T cell activation and tolerance induction, indicating an enhanced immunosuppressive function. These results were further confirmed by flow cytometry analysis and in vitro immune suppression assays. Flow cytometry also revealed a significantly higher proportion of neonatal-TD Treg in total Treg than that of adult-TD counterparts, suggesting the longer lifespan of neonatal-TD Treg. To investigate the intrinsic features of neonatal-TD and adult-TD CD4+ T cells, a shortened tracing time was performed. Surprisingly, the neonatal-TD and adult-TD CD4+ T cells had similar proportions of Treg and did not exhibit significant differences in Foxp3, Gata3, Ctla4, Icos, Il2ra, and Tgfb1 expression levels after tracing for 12 days. On the other hand, neonatal-TD Treg present an increased Nrp1 expression level compared with adult-TD counterparts, indicating the enhanced stability. Together, our work reveals that the neonatal-TD Treg are more immunosuppressive, which is likely shaped primarily by environmental factors.

Dietary ingredient change induces a transient MyD88-dependent mucosal enteric glial cell response and promotes obesity.

OBJECTIVE: Consumption of a modern Western-type high-fat low-fiber diet increases the risk of obesity. However, how a host responds to such a diet, especially during the early period of dietary transition from a previous low-fat and fiber-rich diet, remains poorly explored. METHODS: Wild-type C57BL/6 mice were fed a normal chow diet or a high-fat diet. Enteric glial cell (EGC) activation was detected through quantitative real-time PCR (qRT-PCR), immunoblotting and immunohistology analysis. Fluorocitrate or genetic deletion of glial fibrillary acidic protein (GFAP)-positive glial-intrinsic myeloid differentiation factor 88 (Myd88) was used to inhibit EGC activation, and the effect of a high-fat diet on obesity was further investigated. The role of MYD88-dependent sensing of commensal products in adipocyte was observed to analyze the effect of obesity. RESULTS: A dietary shift from a normal chow diet to a high-fat diet in mice induced a transient early-phase emergence of a GFAP-positive EGC network in the lamina propria of the ileum, accompanied with an increase in glial-derived neurotrophic factor production. Inhibition of glial cell activity blocked this response. GFAP-positive glial Myd88 knockout mice gained less body weight after high-fat diet (HFD) feeding than littermate controls. In contrast, adipocyte deletion of Myd88 in mice had no effect on weight gain but instead exacerbated glucose intolerance. Furthermore, short-term fluorocitrate intervention during HFD feeding attenuated body weight gain. CONCLUSIONS: Our findings indicate that EGCs are early responders to intestinal ecosystem changes and the GFAP-positive glial Myd88 signaling participates in regulating obesity.