New immunosenescence targets for preventing senescence-associated pathological cardiac hypertrophy (SA-PCH) need to be explored. In the present study, with physiologically aged human and mouse samples, the IL-17A level increased with physiological aging, heart failure (HF), and SA-PCH and was negatively correlated with thymic Bmi-1 expression. Bmi-1f/fLckCre+ mice and Bmi-1f/f littermates were generated to determine whether Bmi-1 delayed T cell aging by maintaining thymic T cell development to prevent SA-PCH. As a result, Bmi-1 promoted thymic T cell development by upregulating Notch signaling and prevented DN1 T cells from differentiating into γδT17 cells by downregulating γδT17 cell differentiation signaling. Bmi-1 upregulated Notch signaling by inhibiting p53-mediated Ikzf1 transcription at the -1,863 to -1,849 Ikzf1 promoter region. Bmi-1-RING1B promoted RORγt ubiquitination and degradation by proteasome to inhibit the production of IL-17A in γδT17 cells. Bmi-1 also downregulated Rorc transcribed by c-Maf by trimethylating H3K27 at the -1,511 to -1,497 Rorc promoter region. Subsequently, the number of peripheral γδT17 cells infiltrating the heart tissues was reduced, while alleviating IL-17A-dependent cardiac aging, hypertrophy, dysfunction, senescence-associated secretory phenotype (SASP), and macrophage-myofibroblast transition, ultimately improving SA-PCH. The RORγt inhibitor SR1001 and IL-17A neutralizing antibody ixekizumab prevented thymic RORγt-IL-17A-dependent SA-PCH. Furthermore, RORγt bound to Bmi-1 through ARG237 and to RING1B through GLU235, which could be used as a therapeutic strategy for SA-PCH to construct binding peptides promoting Bmi-1-RING1B binding to RORγt and degrading RORγt for inhibiting γδT17 cell differentiation and IL-17A production. Thus, thymic Bmi-1 prevented IL-17A-dependent SA-PCH by decreasing γδT17 cell numbers.

T helper 17 and Regulatory T cells (Th17 and Treg, respectively) are two well-described lymphocyte subsets with opposing actions. The divergent fates of Th17 and Treg cells are accounted for, at least in part, by molecular antagonism that occurs between their respective specific transcription factors, RORγt and Foxp3. An imbalance between Th17 and Treg cells may lead to tissue inflammation and is associated with certain types of autoimmunity. In order to understand the heterogeneity and dynamics of the differentiation process, we studied Th17/Treg cell differentiation of naïve cells in vitro, using RORγtGFPFoxp3RFP dual-reporter mouse. Flow cytometry revealed the consistent emergence of a population of double positive RORγt+Foxp3+ (DP) cells during the early stages of Th17 cell differentiation. These DP cells are closely related to RORγt+ single positive (SPR) cells in terms of global gene expression. Nevertheless, for some genes, DP cells share an expression pattern with Foxp3+ single positive (SPF) Treg cells, most importantly by reducing IL17 levels. Using time-lapse microscopy, we could delineate the expression dynamics of RORγt and Foxp3 at a clonal level. While the RORγt expression level elevates early during differentiation, Foxp3 rises later and is more stable upon environmental changes. These distinct expression profiles are independent of each other. During differentiation and proliferation, individual cells transit between SPR, DP, and SPF states. Nevertheless, the differentiation of sister cells within a clone progeny was highly correlated. We further demonstrated that sorted SPR and DP populations were not significantly affected by changes in their environment, suggesting that the correlated fate decision emerged at early time points before the first division. Overall, this study provides the first quantitative analysis of differentiation dynamics during the generation of DP RORγt+Foxp3+ cells. Characterizing these dynamics and the differentiation trajectory could provide a profound understanding and be used to better define the distinct fates of T cells, critical mediators of the immune response.

The retinoic acid receptor-related orphan receptor gamma t (RORγt) is a nuclear transcription factor expressed in both innate and adaptive immune cells, driving Th17 cell differentiation and IL-17 production. The IL-23/IL-17 pathway is implicated in autoimmune and inflammatory diseases, and biologics that target IL-23/IL-17 signaling are efficacious in the treatment of psoriasis and psoriatic arthritis. RORγt, at the core of this pathway, represents an attractive opportunity for small-molecule intervention; however, combining high potency, nuclear receptor selectivity, and good physicochemical properties remains a challenge for RORγt inverse agonists. Recently, thiazole amides have been identified as potent RORγt inverse agonists; however, they often suffer from CYP450 autoinduction in the rat, precluding further development. Herein, we describe the discovery and development of potent and selective thiazole bisamide RORγt inverse agonists that avoid autoinduction in the rat. This effort culminated in the discovery of JNJ-61803534, which advanced into phase 1 clinical trials.

The RORγt (nuclear receptor retinoid-related orphan receptor γt) has been identified as a master transcription factor critical for the differentiation of T helper 17 cells, the primary source of IL-17A (interleukin-17A). We previously demonstrated that IL-17A promotes neuroinflammation and sympathetic excitation, contributing to cardiac dysfunction in heart failure and angiotensin II (ANG II)-induced hypertension. The present study sought to determine whether inhibiting RORγt, thereby reducing IL-17A production, could attenuate microglial activation, neuroinflammation, and sympathetic excitation by preserving the integrity of the blood-brain barrier (BBB) in ANG II-induced hypertensive rats.

Rats underwent a 2-week subcutaneous infusion of ANG II, with concurrent daily subcutaneous administration of the RORγt inhibitor digoxin or vehicle.

Compared with controls, ANG II-infused rats exhibited elevated IL-17A levels in both the periphery and brain, along with increased blood pressure and sympathetic tone-effects that were significantly attenuated by inhibiting RORγt with digoxin. ANG II-infused rats also displayed heightened BBB permeability, decreased expression of the BBB regulator Mfsd2a (major facilitator superfamily domain-containing protein 2a), increased caveolar transcytosis, and degradation of tight junction proteins in BBB endothelial cells within the hypothalamic paraventricular nucleus, a key autonomic regulatory brain center, all of which were alleviated by digoxin. Additionally, ANG II-infused rats showed marked microglial activation and elevated expression of proinflammatory cytokines within the paraventricular nucleus, both of which were mitigated by digoxin.

These findings suggest that RORγt inhibition reduces neuroinflammation and sympathetic activation to ameliorate ANG II-induced hypertension, likely by mitigating IL-17A-induced BBB disruption and microglial activation in the paraventricular nucleus.

T helper (Th) 17 and regulatory T (Treg) cells are highly plastic CD4+ Th cell subsets, being able not only to actively adapt to their microenvironment, but also to interconvert, acquiring mixed identity markers. These phenotypic changes are underpinned by transcriptional control mechanisms, chromatin reorganization events and epigenetic modifications, that can be hereditable and stable over time. The Ikaros family of transcription factors have a predominant role in T cell subset specification through mechanisms of transcriptional program regulation that enable phenotypical diversification. They are crucial factors in maintaining Th17/Treg balance and therefore, homeostatic conditions in the tissues. However, they are also implicated in pathogenic processes, where their transcriptional repression contributes to the control of autoimmune processes. In this review, we discuss how T cell fate, specifically in humans, is regulated by the Ikaros family and its interplay with additional factors like the Notch signaling pathway, gut microbiota and myeloid-T cell interactions. Further, we highlight how the transcriptional activity of the Ikaros family impacts the course of T cell mediated chronic inflammatory diseases like rheumatoid and psoriatic arthritis, inflammatory bowel disease, systemic lupus erythematosus and multiple sclerosis. We conclude by discussing recently developed therapeutics designed to target Ikaros family members.

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Acute upper respiratory tract infections are a major public health issue, with uncontrolled inflammation triggered by upper respiratory viruses being a significant cause of patient deterioration or death. This study focuses on the Janus kinase-signal transducer and activator of transcription Rho-associated coiled-coil containing protein kinase (JAK-STAT-ROCK) signaling pathway, providing an in-depth analysis of the interplay between uncontrolled inflammation after upper respiratory tract infections and the development of neurodegenerative diseases. It offers a conceptual framework for understanding the lung-brain-related immune responses and potential interactions. The relationship between the ROCK-JAK-STAT signaling pathway and inflammatory immunity is a complex and multi-layered research area and exploring potential common targets could open new avenues for the prevention and treatment of related inflammation.

Oral microecological imbalance is closely linked to oral mucosal inflammation and is implicated in the development of both local and systemic diseases, including those caused by viral infections. This review examines the critical role of the interleukin (IL)-17/helper T cell 17 (Th17) axis in regulating immune responses within the oral mucosa, focusing on both its protective and pathogenic roles during inflammation. We specifically highlight how the IL-17/Th17 pathway contributes to dysregulated inflammation in the context of respiratory viral infections. Furthermore, this review explores the potential interactions between respiratory viruses and the oral microbiota, emphasizing how alterations in the oral microbiome and increased production of proinflammatory factors may serve as early, non-invasive biomarkers for predicting the severity of respiratory viral infections. These findings provide insights into novel diagnostic approaches and therapeutic strategies aimed at mitigating respiratory disease severity through monitoring and modulating the oral microbiome.

Atherosclerosis serves as the primary catalyst for numerous cardiovascular diseases. Growing evidence suggests that the immune response is involved in every stage of atherosclerotic plaque evolution. Rapid, but not specific, innate immune arms, including neutrophils, monocytes/macrophages, dendritic cells (DCs) and other innate immune cells, as well as pattern-recognition receptors and various inflammatory mediators, contribute to atherogenesis. The specific adaptive immune response, governed by T cells and B cells, antibodies, and immunomodulatory cytokines potently regulates disease activity and progression. In the inflammatory microenvironment, the heterogeneity of leukocyte subpopulations plays a very important regulatory role in plaque evolution. With advances in experimental techniques, the fine mechanisms of immune system involvement in atherosclerotic plaque evolution are becoming known. In this review, we examine the critical immune responses involved in atherosclerotic plaque evolution, in particular, looking at atherosclerosis from the perspective of evolutionary immunobiology. A comprehensive understanding of the interplay between plaque evolution and plaque immunity provides clues for strategically combating atherosclerosis.

In a previous study, it has been shown that the population of Th17 lymphocytes was increased in patients with FMF. IL-21 and IL-23 play significant roles in the production and differentiation of Th17 cells. In this study, we aimed to evaluate serum levels of IL-21 and IL-23 in FMF patients both at diagnosis and after treatment, and to compare these levels with those of healthy controls. Twenty-seven newly diagnosed patients with FMF in attack-free periods and twenty-seven healthy volunteers enrolled in the study. The groups were comparable with respect to age and gender. IL-21 and IL-23 levels in serum samples from patients at the time of diagnosis, in remission after treatment, and from the control groups were analysed using the ELISA method. There was no significant difference between the cytokine levels of the patient group at the time of diagnosis and the cytokine levels of the control group (for IL-21, p: 0.28 and for IL-23, p: 0.56). Similarly, there was no significant difference between the patients' cytokine levels at the time of diagnosis and after treatment (for IL-21, p: 0.99 and for IL-23, p: 0.08). Interleukin levels at the time of diagnosis did not differ among patient groups based on the presence of clinical findings or the M694V genotype. Our results suggest that IL-21 and IL-23 do not play a role in the pathogenesis of the disease. However, while interpreting these findings, it should be considered that patients with active episodes were excluded and cytokine levels were not measured in tissue samples.

Single-gene missense mutations remain challenging to interpret. Here, we deploy scalable functional screening by sequencing (SEUSS), a Perturb-seq method, to generate mutations at protein interfaces of RUNX1 and quantify their effect on activities of downstream cellular programs. We evaluate single-cell RNA profiles of 115 mutations in myelogenous leukemia cells and categorize them into three functionally distinct groups, wild-type (WT)-like, loss-of-function (LoF)-like, and hypomorphic, that we validate in orthogonal assays. LoF-like variants dominate the DNA-binding site and are recurrent in cancer; however, recurrence alone does not predict functional impact. Hypomorphic variants share characteristics with LoF-like but favor protein interactions, promoting gene expression indicative of nerve growth factor (NGF) response and cytokine recruitment of neutrophils. Accessible DNA near differentially expressed genes frequently contains RUNX1-binding motifs. Finally, we reclassify 16 variants of uncertain significance and train a classifier to predict 103 more. Our work demonstrates the potential of targeting protein interactions to better define the landscape of phenotypes reachable by missense mutations.

Association of HLA-B27 with spondyloarthritis (SpA) has been known for 50 years, but still remains unexplained. We recently showed that HLA-B27 expressed in wing imaginal disc from HLA-B27/human-β2 microglobulin (hβ2m) transgenic Drosophila deregulated bone morphogenetic protein (BMP) pathway by interacting physically with type I BMP receptor (BMPR1) Saxophone (Sax), leading to crossveinless phenotype.

Genetic interaction was studied between activin/transforming growth factor β (TGFβ) pathway and HLA-B27/hβ2m in transgenic Drosophila wings. The HLA-B27-bound peptidome was characterized in wing imaginal discs. In mesenteric lymph node (mLN) T cells from HLA-B27/hβ2m rat (B27 rat), physical interaction between HLA-B27 and activin receptor-like kinase-2 (ALK2), ALK3 and ALK5 BMPR1s, phosphorylation of small mothers against decapentaplegic (SMADs) and proteins of the non-canonical BMP/TGFβ pathways induced by its ligands, and the transcript level of target genes of the TGFβ pathway, were evaluated.

In HLA-B27/hβ2m transgenic Drosophila, inappropriate signalling through the activin/TGFβ pathway, involving Baboon (Babo), the type I activin/TGFβ receptor, contributed to the crossveinless phenotype, in addition to deregulated BMP pathway. We identified peptides bound to HLA-B27 with the canonical binding motif in HLA-B27/hβ2m transgenic Drosophila wing imaginal disc. We demonstrated specific physical interaction, between HLA-B27/hβ2m and mammalian orthologs of Sax and Babo, i.e. ALK2 and ALK5 (i.e. TGFβ receptor I), in the mLN cells from B27 rat. The magnitude of phosphorylation of SMAD2/3 in response to TGFβ1 was increased in T cells from B27 rats, showing evidence for deregulated TGFβ pathway. Accordingly, expression of several target genes of the pathway was increased in T cells from B27 rats, in basal conditions and/or after TGFβ exposure, including Foxp3, Rorc, Runx1 and Maf. Interestingly, Tgfb1 expression was reduced in naive T cells from B27 rats, even premorbid, an observation consistent with a pro-inflammatory pattern.

This study shows that HLA-B27 alters the TGFβ pathways in Drosophila and B27 rat. Given the importance of this pathway in CD4 + T cells differentiation and regulation, its disturbance could contribute to the abnormal expansion of pro-inflammatory T helper 17 cells and altered regulatory T cell phenotype observed in B27 rats.

Transcription factors (TFs) regulate gene expression by binding to specific DNA sequences and gating access to genes. Even when the binding of TFs and their cofactors to DNA is reversible, indicating a reversible control of gene expression, there is little knowledge about the molecular effect DNA has on TFs. Using single-molecule multiparameter fluorescence spectroscopy, molecular dynamics simulations, and biochemical assays, we find that the monomeric form of the forkhead (FKH) domain of the human FoxP1 behaves as a disordered protein and increases its folded population when it dimerizes. Notably, DNA binding promotes a disordered FKH dimer bound to DNA, negatively controlling the stability of the dimeric FoxP1:DNA complex. The DNA-mediated reversible regulation on FKH dimers suggests that FoxP1-dependent gene suppression is unstable, and it must require the presence of other dimerization domains or cofactors to revert the negative impact exerted by the DNA.

Microbes influence cancer initiation, progression and therapy responsiveness. IL-17 signaling contributes to gut barrier immunity by regulating microbes but also drives tumor growth. A knowledge gap remains regarding the influence of enteric IL-17-IL-17RA signaling and their microbial regulation on the behavior of distant tumors. We demonstrate that gut dysbiosis induced by systemic or gut epithelial deletion of IL-17RA induces growth of pancreatic and brain tumors due to excessive development of Th17, primary source of IL-17 in human and mouse pancreatic ductal adenocarcinoma, as well as B cells that circulate to distant tumors. Microbial dependent IL-17 signaling increases DUOX2 signaling in tumor cells. Inefficacy of pharmacological inhibition of IL-17RA is overcome with targeted microbial ablation that blocks the compensatory loop. These findings demonstrate the complexities of IL-17-IL-17RA signaling in different compartments and the relevance for accounting for its homeostatic host defense function during cancer therapy.

Nuclear receptor subfamily 1, group D, member 1 (NR1D1, also known as REV-ERBα) belongs to the nuclear receptor (NR) family, and is a heme-binding component of the circadian clock that consolidates circadian oscillators. In addition to repressing the transcription of multiple clock genes associated with circadian rhythms, NR1D1 has a wide range of downstream target genes that are intimately involved in many physiopathological processes, including autophagy, immunity, inflammation, metabolism and aging in multiple organs. This review focuses on the pivotal role of NR1D1 as a key transcription factor in the gene regulatory network, with particular emphasis on the milestones of the latest discoveries of NR1D1 ligands. NR1D1 is considered as a promising drug target for treating diverse diseases and may contribute to research on innovative biomarkers and therapeutic targets for organ injury-related diseases. Further research on NR1D1 ligands in prospective human trials may pave the way for their clinical application in many organ injury-related disorders.

Our previous study had demonstrated that Runx1 promoted LPS-induced macrophage inflammatory response, however, the role of Runx1 in M2 macrophage polarization still remains largely unknown. This study was conducted to investigate the role of Runx1 in IL-4/IL-13-induced M2 macrophage polarization and its potential regulatory mechanism. We found that exposure of macrophages to IL-4/IL-13 induced a remarkable increasement in Runx1 expression level. Specifically, we established genetically modified mice lacking Runx1 in myeloid cells, including macrophages. RNA-Seq was performed to identify differentially expressed genes (DEGs) between Runx1 knockout and WT control bone marrow-derived macrophages (BMDMs). We identified 686 DEGs, including many genes which were highly expressed in M2 macrophage. In addition, bioinformatics analysis indicated that these DEGs were significantly enriched in extracellular matrix-related processes. Moreover, RT-qPCR analysis showed that there was an obvious upregulation in the relative expression levels of M2 marker genes, including Arg1, Ym1, Fizz1, CD71, Mmp9, and Tgm2, in Runx1 knockout macrophages, as compared to WT controls. Consistently, similar results were obtained in the protein and enzymatic activity levels of Arg1. Finally, we found that the STAT6 phosphorylation level was significantly enhanced in Runx1 knockout macrophages, and the STAT6 inhibitor AS1517499 partly reduced the upregulated effect of Runx1 deficiency on the M2 macrophage polarization. Taken together, Runx1 deficiency facilitates IL-4/IL-13-induced M2 macrophage polarization through enhancing STAT6 phosphorylation.

The NR superfamily comprises 48 transcription factors in humans that control a plethora of gene network programs involved in a wide range of physiologic processes. This review will summarize and discuss recent progress in NR biology and drug development derived from integrating various approaches, including biophysical techniques, structural studies, and translational investigation. We also highlight how defective NR signaling results in various diseases and disorders and how NRs can be targeted for therapeutic intervention via modulation via binding to synthetic lipophilic ligands. Furthermore, we also review recent studies that improved our understanding of NR structure and signaling. SIGNIFICANCE STATEMENT: Nuclear receptors (NRs) are ligand-regulated transcription factors that are critical regulators of myriad physiological processes. NRs serve as receptors for an array of drugs, and in this review, we provide an update on recent research into the roles of these drug targets.

Dysregulation of CD4+ T cell differentiation is linked to autoimmune diseases. Metabolic reprogramming from oxidative phosphorylation to glycolysis and accumulation of lactate are involved in this process. However, the underlying mechanisms remain unclear. Our study showed that lactate-derived lactylation regulated CD4+ T cell differentiation. Lactylation levels in CD4+ T cells increased with the progression of experimental autoimmune uveitis (EAU). Inhibition of lactylation suppressed TH17 differentiation and attenuated EAU inflammation. The global lactylome revealed the landscape of lactylated sites and proteins in the CD4+ T cells of normal and EAU mice. Specifically, hyperlactylation of Ikzf1 at Lys164 promoted TH17 differentiation by directly modulating the expression of TH17-related genes, including Runx1, Tlr4, interleukin-2 (IL-2), and IL-4. Delactylation of Ikzf1 at Lys164 impaired TH17 differentiation. These findings exemplify how glycolysis regulates the site specificity of protein lactylation to promote TH17 differentiation and implicate Ikzf1 lactylation as a potential therapeutic target for autoimmune diseases.

Puberty is a critical developmental period of life characterized by marked physiological changes, including changes in the immune system and gut microbiota development. Exposure to inflammation induced by immune stressors during puberty has been found to stimulate central inflammation and lead to immune disturbance at distant sites from the gut; however, its enduring effects on gut immunity are not well explored. Therefore, in this study, we used a pubertal lipopolysaccharides (LPS)-induced inflammation mouse model to mimic pubertal exposure to inflammation and dysbiosis. We hypothesized that pubertal LPS-induced inflammation may cause long-term dysfunction in gut immunity by enduring dysregulation of inflammatory signaling and epigenetic changes, while prebiotic/probiotic intake may mitigate the gut immune system deregulation later in life. To this end, four-week-old female Balb/c mice were fed prebiotics/probiotics and exposed to LPS in the pubertal window. To better decipher the acute and enduring immunoprotective effects of biotic intake, we addressed the effect of treatment on interleukin (IL)-17 signaling related-cytokines and pathways. In addition, the effect of treatment on gut microbiota and epigenetic alterations, including changes in microRNA (miRNA) expression and DNA methylation, were studied. Our results revealed a significant dysregulation in selected cytokines, proteins, and miRNAs involved in key signaling pathways related to IL-17 production and function, including IL-17A and F, IL-6, IL-1β, transforming growth factor-β (TGF-β), signal transducer and activator of transcription-3 (STAT3), p-STAT3, forkhead box O1 (FOXO1), and miR-145 in the small intestine of adult mice challenged with LPS during puberty. In contrast, dietary interventions mitigated the lasting adverse effects of LPS on gut immune function, partly through epigenetic mechanisms. A DNA methylation analysis demonstrated that enduring changes in gut immunity in adult mice might be linked to differentially methylated genes, including Lpb, Rorc, Runx1, Il17ra, Rac1, Ccl5, and Il10, involved in Th17 cell differentiation and IL-17 production and signaling. In addition, prebiotic administration prevented LPS-induced changes in the gut microbiota in pubertal mice. Together, these results indicate that following a healthy diet rich in prebiotics and probiotics is an optimal strategy for programming immune system function in the critical developmental windows of life and controlling inflammation later in life.

The three major mitogen-activated protein kinase (MAPK) pathways (ERK1/2, p38, and JNK/SAPK) are upstream regulators of the nuclear receptor superfamily (NRSF). These ligand-activated transcription factors are divided into subclasses comprising receptors for endocrine hormones, metabolic compounds (e.g., vitamins, diet), xenobiotics, and mediators released from host immune reactions such as tissue injury and inflammation. These internal and external cues place the NRSF at the frontline as sensors and translators of information from the environment towards the genome. For most of the former "orphan" receptors, physiological and synthetic ligands have been identified, opening intriguing opportunities for combination therapies with existing cancer medications. Hitherto, only preclinical data are available, warranting further validation in clinical trials in patients. The current review summarized the existing literature covering the expression and function of NRSF subclasses in human solid tumors and hematopoietic malignancies and their modulatory effects on innate (e.g., macrophages, dendritic cells) and adaptive (i.e., T cell subsets) immune cells, encouraging mechanistic and pharmacological studies in combination with current clinically approved therapeutics against immune checkpoint molecules (e.g., PD1).

Balanced immunity is pivotal for health and homeostasis. CD4+ helper T (Th) cells are central to the balance between immune tolerance and immune rejection. Th cells adopt distinct functions to maintain tolerance and clear pathogens. Dysregulation of Th cell function often leads to maladies, including autoimmunity, inflammatory disease, cancer, and infection. Regulatory T (Treg) and Th17 cells are critical Th cell types involved in immune tolerance, homeostasis, pathogenicity, and pathogen clearance. It is therefore critical to understand how Treg and Th17 cells are regulated in health and disease. Cytokines are instrumental in directing Treg and Th17 cell function. The evolutionarily conserved TGF-β (transforming growth factor-β) cytokine superfamily is of particular interest because it is central to the biology of both Treg cells that are predominantly immunosuppressive and Th17 cells that can be proinflammatory, pathogenic, and immune regulatory. How TGF-β superfamily members and their intricate signaling pathways regulate Treg and Th17 cell function is a question that has been intensely investigated for two decades. Here, we introduce the fundamental biology of TGF-β superfamily signaling, Treg cells, and Th17 cells and discuss in detail how the TGF-β superfamily contributes to Treg and Th17 cell biology through complex yet ordered and cooperative signaling networks.

Lymphocyte apoptosis is a latent factor for immunosuppression in sepsis. Forkhead box protein P3 (FOXP3) can interact with RUNX family transcription factor 1 (RUNX1) in regulatory T cells. Our research was to probe whether RUNX1/FOXP3 axis affects immunosuppression in the process of sepsis by modulating T and B lymphocyte apoptosis. We constructed sepsis model in mice and mouse CD4+ T and CD19+ B lymphocytes. RUNX1 and FOXP3 expressions and apoptosis in cells were assessed by western blot, quantitative real-time PCR, and flow cytometer. Inflammation of serum and pathological damage was assessed by ELISA and H&E staining. Relationship between RUNX1 and FOXP3 was assessed by co-immunoprecipitation. The findings showed that RUNX1 ameliorated the survival rate, pathological damage, and decreased inflammation-related factors, and inhibited apoptosis of CD4+ T and CD19+ B cells in cecal ligation and puncture mice. Furthermore, RUNX1 up-regulated the viability and down-regulated apoptotic rate with the changed expressions of apoptosis-related molecules in lipopolysaccharide (LPS)-mediated CD4+ T and CD19+ B cells. Additionally, FOXP3 interacted with RUNX1, and its silencing decreased RUNX1 expression and reversed the inhibitory effect of RUNX1 on apoptosis of LPS-mediated CD4+ T and CD19+ B cells. In summary, the RUNX1/FOXP3 axis alleviated immunosuppression in sepsis progression by weakening T and B lymphocyte apoptosis.

Understanding the consequences of single amino acid substitutions in cancer driver genes remains an unmet need. Perturb-seq provides a tool to investigate the effects of individual mutations on cellular programs. Here we deploy SEUSS, a Perturb-seq like approach, to generate and assay mutations at physical interfaces of the RUNX1 Runt domain. We measured the impact of 115 mutations on RNA profiles in single myelogenous leukemia cells and used the profiles to categorize mutations into three functionally distinct groups: wild-type (WT)-like, loss-of-function (LOF)-like and hypomorphic. Notably, the largest concentration of functional mutations (non-WT-like) clustered at the DNA binding site and contained many of the more frequently observed mutations in human cancers. Hypomorphic variants shared characteristics with loss of function variants but had gene expression profiles indicative of response to neural growth factor and cytokine recruitment of neutrophils. Additionally, DNA accessibility changes upon perturbations were enriched for RUNX1 binding motifs, particularly near differentially expressed genes. Overall, our work demonstrates the potential of targeting protein interaction interfaces to better define the landscape of prospective phenotypes reachable by amino acid substitutions.

T cells are crucial for immune functions to maintain health and prevent disease. T cell development occurs in a stepwise process in the thymus and mainly generates CD4+ and CD8+ T cell subsets. Upon antigen stimulation, naïve T cells differentiate into CD4+ helper and CD8+ cytotoxic effector and memory cells, mediating direct killing, diverse immune regulatory function, and long-term protection. In response to acute and chronic infections and tumors, T cells adopt distinct differentiation trajectories and develop into a range of heterogeneous populations with various phenotype, differentiation potential, and functionality under precise and elaborate regulations of transcriptional and epigenetic programs. Abnormal T-cell immunity can initiate and promote the pathogenesis of autoimmune diseases. In this review, we summarize the current understanding of T cell development, CD4+ and CD8+ T cell classification, and differentiation in physiological settings. We further elaborate the heterogeneity, differentiation, functionality, and regulation network of CD4+ and CD8+ T cells in infectious disease, chronic infection and tumor, and autoimmune disease, highlighting the exhausted CD8+ T cell differentiation trajectory, CD4+ T cell helper function, T cell contributions to immunotherapy and autoimmune pathogenesis. We also discuss the development and function of γδ T cells in tissue surveillance, infection, and tumor immunity. Finally, we summarized current T-cell-based immunotherapies in both cancer and autoimmune diseases, with an emphasis on their clinical applications. A better understanding of T cell immunity provides insight into developing novel prophylactic and therapeutic strategies in human diseases.

Colorectal cancer is one of the malignant tumors with the highest mortality rate in the world. Survival rates vary significantly among patients at various stages of the disease. A biomarker capable of early diagnosis is required to facilitate the early detection and treatment of colorectal cancer. Human endogenous retroviruses (HERVs) are abnormally expressed in various diseases, including cancer, and have been involved in cancer development. Real-time quantitative PCR was used to detect the transcript levels of HERV-K(HML-2) gag, pol, and env in colorectal cancer to systematically investigate the connection between HERV-K(HML-2) and colorectal cancer. The results showed that HERV-K(HML-2) transcript expression was significantly higher than healthy controls and was consistent at the population and cell levels. We also used next-generation sequencing to identify and characterize HERV-K(HML-2) loci that were differentially expressed between colorectal cancer patients and healthy individuals. The analysis revealed that these loci were concentrated in immune response signaling pathways, implying that HERV-K impacts the tumor-associated immune response. Our results indicated that HERV-K might serve as a screening tumor marker and a target for tumor immunotherapy in colorectal cancer.

Although the activator protein-1 (AP-1) factor Batf is required for Th17 cell development, its mechanisms of action to underpin the Th17 program are incompletely understood. Here, we find that Batf ensures Th17 cell identity in part by restricting alternative gene programs through its actions to restrain IL-2 expression and IL-2-induced Stat5 activation. This, in turn, limits Stat5-dependent recruitment of Ets1-Runx1 factors to Th1- and Treg-cell-specific gene loci. Thus, in addition to pioneering regulatory elements in Th17-specific loci, Batf acts indirectly to inhibit the assembly of a Stat5-Ets1-Runx1 complex that enhances the transcription of Th1- and Treg-cell-specific genes. These findings unveil an important role for Stat5-Ets1-Runx1 interactions in transcriptional networks that define alternate T cell fates and indicate that Batf plays an indispensable role in both inducing and maintaining the Th17 program through its actions to regulate the competing actions of Stat5-assembled enhanceosomes that promote Th1- and Treg-cell developmental programs.

We aimed to evaluate the expression levels and the prognostic value of growth arrest specific 5 (GAS5) and runt-related transcription factor 1 (RUNX1) genes in children with ITP. This prospective cohort study included 100 patients with newly diagnosed ITP (patient group) and 100 healthy children of matched age and sex (control group). We evaluated the expression levels of both GAS5 and RUNX1 genes at the time of diagnosis before the introduction of treatment. GAS5 was under-expressed, while RUNX1 was over-expressed among the newly diagnosed ITP children compared with the control group. Patients with GAS5 levels >0.50 had a significantly faster recovery compared with patients with levels≤0.50 while patients with levels of RUNX1≤2.6 had a significantly faster recovery compared with patients with levels >2.6. The best cut-off values of GAS5 and RUNX1 to predict complete recovery of ITP were ˃0.40 and ˂3.18, respectively, yielding a sensitivity of 76.47% and 79.41%, respectively. The best cut-off values of GAS5 and RUNX1 expression that predict chronic ITP were ˂0.17 and ˃4.1, respectively, yielding sensitivity of 88.89% and 77.78%, respectively. GAS5 and RUNX1 could be useful markers in children with primary ITP to predict disease course.

Disease modifying antirheumatic drugs (DMARDs) have improved the prognosis of autoimmune inflammatory arthritides but a large fraction of patients display partial or nonresponsiveness to front-line DMARDs. Here, an immunoregulatory approach based on sustained joint-localized release of all-trans retinoic acid (ATRA), which modulates local immune activation and enhances disease-protective T cells and leads to systemic disease control is reported. ATRA imprints a unique chromatin landscape in T cells, which is associated with an enhancement in the differentiation of naïve T cells into anti-inflammatory regulatory T cells (Treg ) and suppression of Treg destabilization. Sustained release poly-(lactic-co-glycolic) acid (PLGA)-based biodegradable microparticles encapsulating ATRA (PLGA-ATRA MP) are retained in arthritic mouse joints after intra-articular (IA) injection. IA PLGA-ATRA MP enhance migratory Treg which in turn reduce inflammation and modify disease in injected and uninjected joints, a phenotype that is also reproduced by IA injection of Treg . PLGA-ATRA MP reduce proteoglycan loss and bone erosions in the SKG and collagen-induced arthritis mouse models of autoimmune arthritis. Strikingly, systemic disease modulation by PLGA-ATRA MP is not associated with generalized immune suppression. PLGA-ATRA MP have the potential to be developed as a disease modifying agent for autoimmune arthritis.

Regulatory T (Treg) cells are critical for tolerance to self-antigens and for preventing autoimmunity. Foxp3 has been identified as a Treg cell lineage-defining transcription factor controlling Treg cell differentiation and function. In this article, we review the current mechanistic and systemic understanding of Foxp3 function enabled by experimental and computational advances in high-throughput genomics.

Retinoic acid receptor-related orphan nuclear receptor (ROR)γt regulates the transcription of interleukin-17 and other cytokines implicated in inflammatory and autoimmune diseases. We assessed the safety, tolerability, and pharmacokinetics (PK) of IMU-935, an inverse agonist of RORγt, in a first-in-human phase 1 study. This was a double-blind, placebo-controlled trial that randomly assigned healthy subjects single ascending doses (25-400 mg) or multiple ascending doses (150 mg once or twice daily for 14 days) of IMU-935 or placebo. Dose escalation was determined by the safety, tolerability, and PK. Twenty-four and 70 subjects received placebo or IMU-935, respectively. Of the 70 subjects who received IMU-935, 59 received a single dose and 11 received multiple doses. Treatment-emergent adverse events (TEAEs) occurred in 21 subjects (88%) and 58 (83%) given any dose of placebo or IMU-935, respectively. Treatment-related TEAEs occurred in 6 (30%) and 25 (42%) subjects given a single dose of placebo and IMU-935, respectively. All treatment-related TEAEs were mild except for 2 moderate TEAEs and 1 moderate TEAE in the IMU-935 group and placebo group, respectively. No treatment-related discontinuations or serious adverse events occurred. The PK of IMU-935 were dose proportional with a half-life of ≈24 hours. In conclusion, IMU-935 was safe with no dose-limiting toxicities and had a PK profile that supports once-daily dosing.

Functional mutations or polymorphisms affecting forkhead box P3 (FOXP3) can lead to their abnormal FOXP3 gene expression and/or defective Treg cells generation, thus resulting in autoimmune disease and inflammatory disorders. FOXP3 also plays a key role in Type 2 diabetes mellitus (T2DM) and its complications, because the disease usually involves chronic low-grade inflammatory disorders and is associated with long-term immune system imbalance. This study aimed to investigate the association between FOXP3 polymorphisms and the susceptibility to T2DM and type 2 diabetes nephropathy (T2DN) within the Han Chinese populations.

Polymorphisms in rs3761548C/A and rs2294021C/T were examined in 400 patients (which include an equal number of T2DM and T2DN groups) and 200 healthy controls using PCR-HRM and sequence analysis.

The genotype and allelic frequencies of the two single nucleotide polymorphisms (SNPs) were significantly different in T2DM and the progression of diabetes developing to T2DN. The further gender-based evaluation showed that in female subjects, rs3761548C/A was associated with an approximately 3-fold higher threat for T2DM and 4.5-fold for T2DN, while there was no noticeable association with rs2294021C/T; in males, the promoter polymorphism showed an increased predisposition of 5.4-fold and 3.4-fold predisposition to T2DM and T2DN, respectively, while rs2294021 polymorphism could impart a nearly 2-fold risk of developing T2DN. An additional analysis of combined genotypes (rs3761548 C/A-rs2294021C/T) revealed that CC-CC and CC-CT can be considered protective combinations in the predisposition of males with diabetes towards T2DN, while AA-CC and AA-TT have the opposite effect.

This study demonstrated the possible involvement of individual and combined genetic associations of rs3761548C/A and rs2294021C/T polymorphisms with the susceptibility to diabetes and diabetic nephropathy in the Han Chinese population, as well as gender bias.

CD4 T helper (Th) cell subsets, including Th1, Th2 and Th17 cells, and their innate counterparts innate lymphoid cell (ILC) subsets consisting of ILC1s, ILC2s and ILC3s, display similar effector cytokine-producing capabilities during pro-inflammatory immune responses. These lymphoid cell subsets utilize the same set of lineage-determining transcription factors (LDTFs) for their differentiation, development and functions. The distinct ontogeny and developmental niches between Th cells and ILCs indicate that they may adopt different external signals for the induction of LDTF during lineage commitment. Increasing evidence demonstrates that many conserved cis-regulatory elements at the gene loci of LDTFs are often preferentially utilized for the induction of LDTF expression during Th cell differentiation and ILC development at different stages. In this review, we discuss the functions of lineage-related cis-regulatory elements in inducing T-bet, GATA3 or RORγt expression based on the genetic evidence provided in recent publications. We also review and compare the upstream signals involved in LDTF induction in Th cells and ILCs both in vitro and in vivo. Finally, we discuss the possible mechanisms and physiological importance of regulating LDTF dynamic expression during ILC development and activation.

T helper 17 (Th17) cells represent a specialized subgroup of effector CD4+ T cells known for their role in provoking neutrophil-driven tissue inflammation, particularly within mucosal tissues. Although they are pivotal for defending the host against extracellular bacteria and fungi, they have also been associated with development of various T cell-mediated inflammatory conditions, autoimmune diseases, and even cancer. Notably, Th17 cells exhibit a dual nature, with different Th17 cell subtypes showcasing distinct effector functions and varying capacities to incite autoimmune tissue inflammation. Furthermore, Th17 cells exhibit significant plasticity, which carries important functional implications, both in terms of their expression of cytokines typically associated with other effector T cell subsets and in their interactions with regulatory CD4+ T cells. The intricate balance of Th17 cytokines can also be a double-edged sword in inflammation, autoimmunity, and cancer. Within this article, we delve into the mechanisms that govern the differentiation, function, and adaptability of Th17 cells. We culminate with an exploration of therapeutic potentials in harnessing the power of Th17 cells and their cytokines. Targeted interventions to modulate Th17 responses are emerging as promising strategies for autoimmunity, inflammation, and cancer treatment. By precisely fine-tuning Th17-related pathways, we may unlock new avenues for personalized therapeutic approaches, aiming to restore immune balance, alleviate the challenges of these disorders, and ultimately enhance the quality of life for individuals affected by them.

The pleiotropic actions of the Farnesoid X Receptor (FXR) are required for gut health, and reciprocally, reduced intestinal FXR signaling is seen in inflammatory bowel diseases (IBDs). Here, we show that activation of FXR selectively in the intestine is protective in inflammation-driven models of IBD. Prophylactic activation of FXR restored homeostatic levels of pro-inflammatory cytokines, most notably IL17. Importantly, these changes were attributed to FXR regulation of innate lymphoid cells (ILCs), with both the inflammation-driven increases in ILCs, and ILC3s in particular, and the induction of Il17a and Il17f  in ILC3s blocked by FXR activation. Moreover, a population of ILC precursor-like cells increased with treatment, implicating FXR in the maturation/differentiation of ILC precursors. These findings identify FXR as an intrinsic regulator of intestinal ILCs and a potential therapeutic target in inflammatory intestinal diseases.

Mycobacterium leprae is a kind of disease-causing bacteria and results in leprosy in human. Gamma delta (γδ) T cell is a T-cell subset that is presented in both human dermis and epidermis. These cells bridge innate and adaptive immune responses and play critical roles in regulating anti-microbial defense, wound healing, and skin inflammation. Here, we investigated skin resident γδ T cells in patients with leprosy. Our data showed that γδ T cells significantly accumulated in skin lesions of leprosy patients with tuberculoid (TT) form. IL-23 can predominantly stimulate dermal γδ T cells to produce interleukin 17 (IL-17), a cytokine which may lead to disease protection. These γδ T cells expressed a specific set of surface molecules, and majority of these cells were Vδ1+. Also, IL-23 can stimulate the expansion of dermal γδ T cells expansion. Moreover, our results revealed that the transcription factor RORγt was responsible for IL-17A expression in leprosy lesion. Therefore, these data indicated that IL-23-responsive dermal γδ T cells were the major resource of IL-17A production in the skin and could be a potential target in the treatment of leprosy.