Immune thrombocytopenia (ITP) is a hemorrhagic autoimmune disease characterized by antibody-mediated platelet injury. ITP has complicated immunopathological mechanisms that need further elucidation. It is well known that the costimulatory molecules OX40 ligand (OX40L) and OX40 play essential roles in the immunological mechanisms of autoimmune diseases. Previously, we discovered that the expression of OX40L and OX40 is significantly increased in the peripheral blood mononuclear cells (PBMCs) of ITP patients. In our present study, OX40L-induced follicular helper T (Tfh) cells exhibited an activated phenotype with elevated expression of inducible T-cell costimulator (ICOS), programmed cell death protein-1 (PD-1), and cluster of differentiation 40 ligand (CD40L) in vitro. Moreover, aberrant OX40L‒OX40 expression might promote the Tfh1-to-Tfh2 shift in vivo, inducing the generation of autoantibodies by enhancing the helper function of Tfh cells for B lymphocytes in a mouse model, which might accelerate the progression of ITP. Additionally, signal transduction through the OX40L‒OX40 axis might be related to the activation of tumor necrosis factor receptor-associated factor (TRAF)‒nuclear factor-κB (NF-κB) and Janus kinase (JAK)‒signal transducer and activator of transcription (STAT) signaling pathways. Overall, OX40L‒OX40 signaling is proposed as a potential novel therapeutic target for ITP.
Animals ; OX40 Ligand/physiology* ; Purpura, Thrombocytopenic, Idiopathic/immunology* ; Cell Differentiation ; Mice ; T-Lymphocytes, Helper-Inducer/cytology* ; T Follicular Helper Cells/cytology* ; Signal Transduction ; Receptors, OX40 ; Mice, Inbred C57BL ; Humans ; Female

OBJECTIVES: To investigate the therapeutic effects of cimifugin on Crohn's disease (CD)-like colitis in mice and its possible mechanism. METHODS: Thirty adult male C57BL/6 mice were randomized equally into control group, 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced CD-like colitis model group, and cimifugin treatment (daily gavage at 12.5 mg/kg) group. The therapeutic effect of cimifugin was evaluated by observing changes in body weight, disease activity index (DAI) scores, colon length, histopathological inflammation scores, and inflammatory cytokine levels in the colonic mucosa. Intestinal barrier integrity in the mice was assessed using immunofluorescence assay and Western blotting for claudin-1 and ZO-1; T-helper (Th) cell subset ratios in the mesenteric lymph nodes were analyzed with flow cytometry. Network pharmacology, KEGG enrichment analysis and molecular docking were used to predict the targets of cimifugin and analyze the key pathways and cimifugin-MAPK protein interactions, which were validated by Western blotting in the mouse models. RESULTS: In mice with TNBS-induced colitis, cimifugin treatment significantly attenuated body weight loss and colon shortening, lowered DAI and histopathological scores, decreased IFN-γ and IL-17 levels, and increased IL-4 and IL-10 levels in the colonic mucosa. Cimifugin treatment also significantly improved TNBS-induced claudin-1 dislocation and reduction of goblet cells, upregulated claudin-1 and ZO-1 expressions, reduced Th1 and Th17 cell percentages, and increased Th2 and Treg cell percentages in the colonic mucosa of the mice. KEGG analysis suggested a possible connection between the effect of cimifugin and MAPK signaling, and molecular docking showed strong binding affinity between cimifugin and MAPK core proteins. Western blotting demonstrated significantly decreased phosphorylation levels of JNK, ERK, and p38 in the colonic mucosa of cimifugin-treated mouse models. CONCLUSIONS Cimifugin alleviates TNBS-induced CD-like colitis by repairing intestinal barrier damage and restoring Th1/Th2 and Th17/Treg balance via suppressing MAPK pathway activation.
Animals ; Mice, Inbred C57BL ; Male ; Mice ; Crohn Disease/immunology* ; Colitis/immunology* ; MAP Kinase Signaling System/drug effects* ; Trinitrobenzenesulfonic Acid ; T-Lymphocytes, Helper-Inducer/drug effects* ; Intestinal Mucosa ; Disease Models, Animal

OBJECTIVES: To investigate the characteristics of immune cell infiltration in tumor samples from Chinese patients with clear cell renal cell carcinoma (ccRCC) and the correlation of immune cell infiltration with tumor stage and response to immunotherapy. METHODS: Tumor samples and clinicopathological data were collected from 154 ccRCC patients treated in Nanfang Hospital, Southern Medical University from October, 2020 to October, 2023. The immune cell types infiltrating the tumor tissues were identified using immunohistochemistry and immunofluorescence staining, and their correlations with the patients' clinicopathological characteristics were analyzed. Patient-derived tumor tissue fragment models (PDTF) models, constructed using tumor tissues from 22 patients, were treated with PD-1 monoclonal antibody, and T cell activation was detected using flow cytometry to assess the patients' responses to immunotherapy. RESULTS: In Chinese ccRCC patients included in this study, CD8⁺ T cells, CD4⁺ T cells, and CD3⁺ T cells were the most abundant in the tumor tissues. Higher infiltration levels of CD3⁺ T cells (P=0.004), PD-1⁺ T cells (P=0.020), CD68⁺ T cells (P=0.049), CD79⁺ T cells (P=0.049), and Tryptase⁺ cells (P=0.049) were all positively correlated with a larger tumor size (≥5 cm). A higher infiltration level of CD4⁺ T cells was associated with a lower tumor stage. Patients with higher International Society of Urological Pathology (ISUP) grades had higher infiltration levels of CD3⁺ T cells (P=0.023), CD8⁺ T cells (P=0.045), PD-1⁺ T cells (P=0.014), CD20⁺ B cells (P=0.020) and CD79⁺ B cells (P=0.049), and lower levels of Tryptase⁺ cells (P=0.001). Patients with abundant infiltrating immune cells tended to have better responses to immunotherapy. CONCLUSIONS The infiltrating immune cells are heterogeneous in Chinese ccRCC patients, and immune cell infiltration characteristics are closely correlated with clinicopathological parameters of the patients.
Humans ; Carcinoma, Renal Cell/pathology* ; Kidney Neoplasms/pathology* ; Immunotherapy ; Male ; Lymphocytes, Tumor-Infiltrating/immunology* ; Female ; Middle Aged ; CD8-Positive T-Lymphocytes/immunology* ; Aged ; T-Lymphocytes/immunology* ; Programmed Cell Death 1 Receptor/immunology* ; Adult ; CD4-Positive T-Lymphocytes/immunology* ; Neoplasm Staging

OBJECTIVES: To investigate the inhibitory effect of pirfenidone (PFD) on growth of bladder cancer xenograft and its regulatory effect on Treg cells in tumor-bearing mice. METHODS: Thirty-two C57BL/6 mice bearing ectopic bladder tumors were randomized into control and PFD groups (n=16). In PFD group, PFD was administered orally at the daily dose of 500 mg/kg, and tumor growth and survival of the mice were monitored. After treatment for 21 days, the tumors and vital organs were harvested for analysis. Immunohistochemistry was used to assess CD3, CD4, CD8, and FOXP3 expressions in the tumors. Flow cytometry and RT-qPCR were used to analyze the percentage of CD4⁺CD25⁺FOXP3⁺ Treg cells and IL-2, IL-10, and IL-35 expressions in the tumors and spleens; organ damage of the mice was examined with HE staining. RESULTS: Compared with the control group, the PFD-treated mice exhibited significantly lower tumor growth rate with smaller tumor volumes at day 21, along with improved survival at day 28. Immunohistochemistry revealed no significant differences in the infiltration of CD3⁺ and CD8⁺ cells between the two groups, but the percentages of CD4⁺ and FOXP3⁺ cells were significantly lower in the tumors of PFD-treated mice. Flow cytometric analysis confirmed a decrease in CD4⁺CD25⁺FOXP3⁺ Treg cells in the tumors from PFD-treated mice, which also had reduced expression levels of IL-2, IL-10 and IL-35 mRNAs in the tumors. No significant differences were found in Treg cell populations or cytokine expressions in the spleen tissues between the two groups. HE staining showed obvious organ damage in neither of the groups. CONCLUSIONS PFD inhibits bladder cancer growth and enhances survival of tumor-bearing mice possibly by suppressing Treg cells in the tumor microenvironment.
Animals ; Urinary Bladder Neoplasms/drug therapy* ; Mice ; T-Lymphocytes, Regulatory/metabolism* ; Mice, Inbred C57BL ; Interleukins/metabolism* ; Interleukin-10/metabolism* ; Cell Line, Tumor ; Interleukin-2/metabolism* ; Xenograft Model Antitumor Assays ; Female

Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model, experimental autoimmune encephalomyelitis (EAE). This study investigates the role of high mobility group box 1 (HMGB1) in oligodendrocyte precursor cells (OPCs) in modulating pathogenic T cells infiltrating the central nervous system through the blood-brain barrier (BBB) by using OPC-specific HMGB1 knockout (KO) mice. We found that HMGB1 released from OPCs promotes BBB disruption, subsequently allowing increased immune cell infiltration. The migration of CD4+ T cells isolated from EAE-induced mice was enhanced when co-cultured with OPCs compared to oligodendrocytes (OLs). OPC-specific HMGB1 KO mice exhibited lower BBB permeability and reduced immune cell infiltration into the CNS, leading to less damage to the myelin sheath and mitigated EAE progression. CD4+ T cell migration was also reduced when co-cultured with HMGB1 knock-out OPCs. Our findings reveal that HMGB1 secretion from OPCs is crucial for regulating immune cell infiltration and provides insights into the immunomodulatory function of OPCs in autoimmune diseases.
Animals ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; HMGB1 Protein/deficiency* ; Mice, Knockout ; Oligodendrocyte Precursor Cells/immunology* ; Mice, Inbred C57BL ; CD4-Positive T-Lymphocytes/immunology* ; Cell Movement ; Blood-Brain Barrier/immunology* ; Mice ; Myelin Sheath/pathology* ; Disease Models, Animal ; Coculture Techniques ; Oligodendroglia/metabolism* ; Female ; Cells, Cultured

Extensive epigenetic reprogramming involves in memory CD8+ T-cell differentiation. The elaborate epigenetic rewiring underlying the heterogeneous functional states of CD8+ T cells remains hidden. Here, we profile single-cell chromatin accessibility and map enhancer-promoter interactomes to characterize the differentiation trajectory of memory CD8+ T cells. We reveal that under distinct epigenetic regulations, the early activated CD8+ T cells divergently originated for short-lived effector and memory precursor effector cells. We also uncover a defined epigenetic rewiring leading to the conversion from effector memory to central memory cells during memory formation. Additionally, we illustrate chromatin regulatory mechanisms underlying long-lasting versus transient transcription regulation during memory differentiation. Finally, we confirm the essential roles of Sox4 and Nrf2 in developing memory precursor effector and effector memory cells, respectively, and validate cell state-specific enhancers in regulating Il7r using CRISPR-Cas9. Our data pave the way for understanding the mechanism underlying epigenetic memory formation in CD8+ T-cell differentiation.
CD8-Positive T-Lymphocytes/metabolism* ; Cell Differentiation ; Chromatin/immunology* ; Animals ; Mice ; Immunologic Memory ; Epigenesis, Genetic ; SOXC Transcription Factors/immunology* ; NF-E2-Related Factor 2/immunology* ; Mice, Inbred C57BL ; Gene Regulatory Networks ; Enhancer Elements, Genetic

Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable efficacy in treating hematological malignancies and is expanding into other indications such as autoimmune diseases, fibrosis, aging and viral infection. However, clinical challenges persist in treating solid tumors, including physical barriers, tumor heterogeneity, poor in vivo persistence, and T-cell exhaustion, all of which hinder therapeutic efficacy. This review focuses on the critical role of tonic signaling in CAR-T therapy. Tonic signaling is a low-level constitutive signaling occurring in both natural and engineered antigen receptors without antigen stimulation. It plays a pivotal role in regulating immune cell homeostasis, exhaustion, persistence, and effector functions. The "Peak Theory" suggests an optimal level of tonic signaling for CAR-T function: while weak tonic signaling may result in poor proliferation and persistence, excessively strong signaling can cause T cell exhaustion. This review also summarizes the recent progress in mechanisms underlying the tonic signaling and strategies to fine-tune the CAR tonic signaling. By understanding and precisely modulating tonic signaling, the efficacy of CAR-T therapies can be further optimized, offering new avenues for treatment across a broader spectrum of diseases. These findings have implications beyond CAR-T cells, potentially impacting other engineered immune cell therapies such as CAR-NK and CAR-M.
Humans ; Immunotherapy, Adoptive/methods* ; Receptors, Chimeric Antigen/immunology* ; Signal Transduction/immunology* ; T-Lymphocytes/immunology* ; Neoplasms/immunology* ; Animals

Postmenopausal osteoporosis (PMOP) is a systemic metabolic bone disease caused by the decrease in estrogen levels after menopause. It leads to bone loss, microstructural damage, and an increased risk of fractures. Studies have found that the gut microbiota and its metabolites can regulate bone metabolism through the gut-bone axis and the gut-brain axis. As research progresses, PMOP has been found to be associated with gut microbiota dysbiosis and Th17/Treg imbalance. The gut microbiota is closely related to the development and differentiation of Treg and Th17 cells. Among them, the metabolites of the gut microbiota such as short-chain fatty acids (SCFAs) can regulate the differentiation of effector T cells by acting on molecular receptors on immune cells, thereby regulating the bone immune process. The multifaceted relationship among the gut microbiota, SCFAs, Th17/Treg cell-mediated bone immunity, and bone metabolism is eliciting attention from researchers. Through a review of existing literature, we have comprehensively summarized the effects of the gut microbiota and SCFAs on PMOP, especially from the perspective of Th17/Treg balance. Regulating this balance may provide new opportunities for PMOP treatment.
Humans ; Gastrointestinal Microbiome/immunology* ; Fatty Acids, Volatile/metabolism* ; Osteoporosis, Postmenopausal/immunology* ; Female ; T-Lymphocytes, Regulatory/metabolism* ; Th17 Cells/metabolism* ; Dysbiosis/immunology* ; Bone and Bones/metabolism*

Objective This study investigated the regulatory effect of high mobility group protein B1 (HMGB1) in the peripheral blood of patients with primary immune thrombocytopenia (ITP) on myeloid dendritic cells (mDC) and Th17/regulatory T cells (Treg) balance. Methods The study enrolled 30 newly diagnosed ITP patients and 30 healthy controls.Flow cytometry was used to measure the proportion of mDC, Th17, and Treg cells in the peripheral blood of ITP patients and healthy controls. ELISA was conducted to quantify the serum levels of HMGB1, interleukin 6 (IL-6), IL-23, IL-17, and transforming growth factor β(TGF-β). The mRNA levels of retinoic acid-related orphan receptor γt(RORγt) and forehead box P3(FOXP3) were detected by real-time PCR. The correlation between the abovementioned cells, cytokines, and platelet count was assessed using Pearson linear correlation analysis. Results The proportion of Th17 cells and the expression levels of HMGB1, IL-6, IL-23, IL-17 and the level of RORγt mRNA in the peripheral blood of ITP patients were higher than those in healthy controls. However, the Treg cell proportion and TGF-β level were lower in ITP patients than those in healthy controls. In patients with ITP, the proportion of mDC and the level of FOXP3 mRNA did not show significant changes. The proportion of mDC cells was significantly correlated with the expression of IL-6 and IL-23. Moreover, the expression of HMGB1 showed a significant correlation with the expression of mDC, IL-6, IL-23, RORγt mRNA, and IL-17. Notably, both the proportion of mDC cells and the expression of HMGB1 were negatively correlated with platelet count. Conclusion The high expression of HMGB1 in peripheral blood of ITP patients may induce Th17/Treg imbalance by promoting the maturation of mDC and affecting the secretion of cytokines, thereby potentially playing a role in the immunological mechanism of ITP.
Humans ; Th17 Cells/cytology* ; HMGB1 Protein/genetics* ; T-Lymphocytes, Regulatory/cytology* ; Female ; Male ; Dendritic Cells/metabolism* ; Adult ; Middle Aged ; Purpura, Thrombocytopenic, Idiopathic/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 3/genetics* ; Young Adult ; Interleukin-23/blood* ; Interleukin-17/blood* ; Interleukin-6/blood* ; Forkhead Transcription Factors/genetics* ; Myeloid Cells/cytology* ; Aged

Cytotoxic CD4⁺ T cells (CD4⁺ CTLs) represent a novel subset of T cells with cytotoxic effects. They recognize target cells in an antigen-specific manner, relying on class II major histocompatibility complex (MHC-II) interactions. CD4⁺ CTLs exert cytotoxic effects on target cells by secreting cytotoxic molecules such as granzymes, perforin, and granulysin. Recent studies have revealed their significant roles in various autoimmune diseases. This review focuses on the differentiation, phenotypic characteristics, and roles of CD4⁺ CTLs in different types of autoimmune disorders, aiming to provide new insights for the prevention and treatment of these diseases.
Humans ; Autoimmune Diseases/immunology* ; CD4-Positive T-Lymphocytes/immunology* ; Animals ; T-Lymphocytes, Cytotoxic/immunology* ; Perforin/immunology* ; Granzymes/immunology*