Age-associated CD4+ T cells with B cell-promoting functions are regulated by ZEB2 in autoimmunity

Targeting T-cell Aging to Remodel the Aging Immune System and Revitalize Geriatric Immunotherapy

The aging immune system presents profound challenges, notably through the decline of T cell function, which is critical for effective immune responses. As age-related changes lead to diminished T cell diversity and heighten immunosuppressive environments, older individuals face increased susceptibility to infections, autoimmune diseases, and reduced efficacy of immunotherapies. This review investigates the intricate mechanisms by which T cell aging drives immunosenescence, including immune suppression, immune evasion, reduced antigen reactivity, and the overexpression of immune checkpoint molecules. By delving into innovative therapeutic strategies aimed at rejuvenating T cell populations and modifying the immunological landscape, we highlight the potential for enhancing immune resilience in the elderly. Ultimately, our goal is to outline actionable pathways for restoring immune function, thereby improving health outcomes for aging individuals facing immunological decline.

Polarization of the memory B-cell response

Memory B cells are long-lived cells that are induced following infection or vaccination. Upon antigen re-encounter, memory B cells rapidly differentiate into antibody-secreting or germinal center B cells. While memory B cells are an important component of long-term protective immunity following vaccination, they also contribute to the progression of diseases such as autoimmunity and allergy. Numerous subsets of memory B cells have been identified in mice and humans that possess important phenotypic and functional differences. Here, we review the transcriptional circuitry governing memory B-cell differentiation and function. We then summarize emerging evidence that the inflammatory environment in which memory B cells develop has an important role in shaping their phenotype and examine the pathways regulating the development of memory B cells during a type 1-skewed and type 2-skewed immune response.

Redox regulation: mechanisms, biology and therapeutic targets in diseases

Redox signaling acts as a critical mediator in the dynamic interactions between organisms and their external environment, profoundly influencing both the onset and progression of various diseases. Under physiological conditions, oxidative free radicals generated by the mitochondrial oxidative respiratory chain, endoplasmic reticulum, and NADPH oxidases can be effectively neutralized by NRF2-mediated antioxidant responses. These responses elevate the synthesis of superoxide dismutase (SOD), catalase, as well as key molecules like nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH), thereby maintaining cellular redox homeostasis. Disruption of this finely tuned equilibrium is closely linked to the pathogenesis of a wide range of diseases. Recent advances have broadened our understanding of the molecular mechanisms underpinning this dysregulation, highlighting the pivotal roles of genomic instability, epigenetic modifications, protein degradation, and metabolic reprogramming. These findings provide a foundation for exploring redox regulation as a mechanistic basis for improving therapeutic strategies. While antioxidant-based therapies have shown early promise in conditions where oxidative stress plays a primary pathological role, their efficacy in diseases characterized by complex, multifactorial etiologies remains controversial. A deeper, context-specific understanding of redox signaling, particularly the roles of redox-sensitive proteins, is critical for designing targeted therapies aimed at re-establishing redox balance. Emerging small molecule inhibitors that target specific cysteine residues in redox-sensitive proteins have demonstrated promising preclinical outcomes, setting the stage for forthcoming clinical trials. In this review, we summarize our current understanding of the intricate relationship between oxidative stress and disease pathogenesis and also discuss how these insights can be leveraged to optimize therapeutic strategies in clinical practice.

The role of polyreactive memory B cells in systemic lupus erythematosus

In systemic lupus erythematosus (SLE), the production of autoantibodies is a crucial characteristic, and B cells play a significant role in its pathogenesis. B cells are the immune cells most associated with the genetic predispositions of SLE, and recent clinical studies showing that anti-CD19 chimeric antigen receptor (CAR)-T cell therapy induces drug-free remission have underscored the importance of B cells in SLE. Meanwhile, various B-cell subsets exist across different stages of differentiation, from naive B cells to plasma cells, and identifying the important subpopulations within SLE remains a critical future challenge. Years of B-cell repertoire analyses have revealed the importance of polyreactive B-cell receptors (BCRs) and autoantibodies that react to various self-antigens and microbial antigens. Particularly, memory B cells with polyreactive BCRs, which play a crucial role in biological defense during the fetal stage, are characteristically differentiated in SLE. Type I interferon-mediated expression of CXCL13 and IL-21 in CD4+ T cells is associated with the development of polyreactive memory B cells. The expansion of the polyreactive B-cell repertoire, vital for defending against infections such as viruses, may exert an intrinsic function in SLE.

General and individualized changes in T cell immunity during aging

Functional alterations with age are observed in all human systems, but the aging of the adaptive immune system displays both general changes affecting all individuals, and idiosyncratic changes that are unique to individuals. In the T cell compartment, general aging manifests in three ways: (1) the reduction of naïve T cells, (2) the accumulation of differentiated memory T cells, and (3) a reduced overall T cell receptor (TCR) repertoire. Idiosyncratic impacts of aging, such as changes in the TCR repertoires of altered memory and naïve T cells are shaped by each person's life exposures. Recent advancements in single-cell sequencing provide new information including the identification of new subpopulations of T cells, characteristics of transcriptome changes in T cells and their TCR clonotype with age, and measurement of individual cell age. Here, we focus on the changes in T cell subpopulations, transcriptomes and TCR repertoires in overall and antigen-specific T cell population with aging.

CX3CR1+ age-associated CD4+ T cells contribute to synovial inflammation in late-onset rheumatoid arthritis

BACKGROUND

Recent evidence suggests that clonally expanded cytotoxic T cells play a role in various autoimmune diseases. Late-onset rheumatoid arthritis (LORA) exhibits unique characteristics compared to other RA forms, suggesting distinct immunological mechanisms. This study aimed to examine the involvement of cytotoxic T cells in LORA.

METHODS

Fresh peripheral blood samples were collected from 78 treatment-naïve active RA patients, 12 with difficult-to-treat RA, and 16 healthy controls. Flow cytometry was employed to measure the proportions of CX3CR1+cytotoxic CD4+ and CD8+ T cells in these samples. Additionally, immunohistochemical staining was performed on lymphoid node and synovial biopsy samples from patients with RA.

RESULTS

CX3CR1+cytotoxic CD4+ T cells were specifically increased in untreated, active patients with LORA, displaying features of CXCR3mid age-associated T helper cells known as "ThA". CX3CR1⁺CD4⁺ T cells were identified as a cytotoxic ThA subset, as nearly all of these cells specifically expressed granzyme B. These cells were observed in enlarged lymph nodes and were found to infiltrate synovial tissues from patients with LORA. The proportions of CX3CR1+CD4+ T cells positively correlated with arthritis activity in LORA. The number of cells decreased after treatment with methotrexate, tumor necrosis factor inhibitors, and interleukin-6 inhibitors, whereas T-cell activation modulators did not affect them. Moreover, PD-1+CD38+CX3CR1+CD4+ T cells were identified as a treatment-resistant T cell subset that was characteristically increased in difficult-to-treat RA. CX3CR1+CD8+ T cells showed no significant difference between RA patients and healthy individuals, and no correlation with disease activity was observed. However, a correlation with age was observed in RA patients.

CONCLUSIONS

Our findings suggest that the immunopathogenesis of RA differs by age of onset, with CX3CR1+ age-associated cytotoxic CD4+ T cells playing a significant role in LORA. Additionally, the presence of a specific CX3CR1+ T cell subset may be linked to treatment resistance.

An abnormal increase in CD26(-)CD28(-) cytotoxic effector CD4 and CD8 T cell populations in patients with systemic lupus erythematosus

CD26 is a human T cell costimulatory molecule as well as a T cell subset marker, and the increase of CD26+ T cells in inflamed tissues and peripheral blood has been reported in diverse autoimmune diseases. In contrast, our group has previously shown that levels of circulating CD26+ T cells are decreased in patients with systemic lupus erythematosus (SLE), although the role of reduced CD26 T cell surface expression in SLE pathology remains to be elucidated. In the present study, we conducted CD26-based T cell subset analyses utilizing peripheral blood mononuclear cells from 57 SLE patients and 31 healthy adult volunteers. We show that the increase in the CD26(-) T cell population reflects the abnormal expansion of CD26(-)CD28(-) cytotoxic subsets of both CD8 T cells and CD4 T cells in SLE patients. Single-cell RNA sequencing analysis of the CD26(-)CD28(-) CD4 and CD8 T cell populations reveals unique characteristics with similarities to natural killer T cells. In addition, the level of CD26(-)CD28(-) T cells is increased in some active-stage SLE patients with renal manifestation. Meanwhile, the effect of prednisolone treatment on these populations varies from patient to patient, with levels of these cytotoxic effector populations still being elevated in some inactive-stage SLE patients. Taken together, our data suggest that analysis of these populations in SLE may be a useful tool to classify this markedly heterogeneous condition.

Senescence-associated T cells in immunosenescence and diseases

Age-related changes in the immune system, referred to as immunosenescence, appear to evolve with rather paradoxical manifestations, a diminished adaptive immune capacity, and an increased propensity for chronic inflammation often with autoimmunity, which may underlie the development of diverse disorders with age. Immunosenescent phenotypes are associated with the emergence of unique lymphocyte subpopulations of both T and B lineages. We report that a CD153+ programmed cell death protein 1 (PD-1)+ CD4+ T-cell subpopulation with severely attenuated T-cell receptor (TCR)-responsiveness, termed senescence-associated T (SAT) cells, co-evolve with potentially autoreactive CD30+ B cells, such as spontaneous germinal center B cells and age-associated B cells, in aging mice. SAT cells and CD30+ B cells are reciprocally activated with the aid of the interaction of CD153 with CD30 in trans and with the TCR complex in cis, resulting in the restoration of TCR-mediated proliferation and secretion of abundant pro-inflammatory cytokines in SAT cells and the activation and production of autoantibodies by CD30+ B cells. Besides normal aging, the development of SAT cells coupled with counterpart B cells may be robustly accelerated and accumulated in the relevant tissues of lymphoid or extra-lymphoid organs under chronic inflammatory conditions, including autoimmunity, and may contribute to the pathogenesis and aggravation of the disorders. This review summarizes and discusses recent advances in the understanding of SAT cells in the contexts of immunosenescent phenotypes, as well as autoimmune and chronic inflammatory diseases, and it provides a novel therapeutic clue.

Cytotoxic Response of CD4+ T Cells Orchestrated by SLAMF4 in Rheumatoid Arthritis

OBJECTIVE

This study aimed to assess whether signaling lymphocytic activation molecule family receptors (SLAMFs) are involved in the shaping of the pathologic response of CD4+ T cells in rheumatoid arthritis (RA).

METHODS

Peripheral blood (PB) and synovial fluid (SF) mononuclear cells from patients with RA were freshly isolated. In RA, we used a multimodal approach to determine the involvement of numerous subpopulations of CD4+ T cells expressing SLAMFs. Experimentally, multiple flow cytometry panels, RNA sequencing, and stimulations were used. Analyses involved high-dimensional unsupervised clustering of flow cytometry data and pathway enrichment analyses of transcriptomic data.

RESULTS

In PB of patients with RA with active disease, SLAMF4+ effector memory CD4+ T cells (Tem) represented the only overrepresented subpopulation of CD4+ T cells expressing SLAMFs. This positive correlation between RA activity and SLAMF4+ Tem was restricted to those coexpressing the intracellular molecule SLAM-associated protein (SAP) and the tissue-homing receptor CCR5. Gene Set Enrichment Analysis of RNA sequencing data reveals that SLAMF4+ CCR5+ Tem display a cytotoxicity-related gene signature. Moreover, based on the differential expression of cytotoxicity markers (GPR56, CX3CR1, granzyme-B, perforin, and granulysin), unsupervised clustering of flow cytometry data identified distinct subpopulations of PB cytotoxic Tem. Among them, only SLAMF4high SAP+ CCR5+ Tem (Cytotox-F4high Tem) were correlated with RA activity. Remarkably, Cytotox-F4high Tem emerged as the only cytotoxic population of CD4+ T cells (CD4+ CTLs) present in SF of patients with active disease.

CONCLUSION

This study emphasizes that Cytotox-F4high Tem represent a significant CD4+ CTL subpopulation involved in RA, suggesting that their inhibition represent a promising therapeutic interest.

Muscle Tissue Transcriptome of Idiopathic Inflammatory Myopathy Reflects the Muscle Damage Process by Monocytes and Presence of Skin Lesions

OBJECTIVE

We aim to investigate transcriptomic and immunophenotypic features of muscle specimens from patients with idiopathic inflammatory myopathy (IIM).

METHODS

Bulk RNA-sequencing was performed on muscle biopsy samples from 16 patients with dermatomyositis (DM) and 9 patients with polymyositis (PM). Seven tested positive for anti-aminoacyl transfer RNA synthetase antibodies in the patients with DM (ARS-DM). We conducted weighted gene coexpression network analysis (WGCNA), differentially expressed gene (DEG) analysis, and gene set variation analysis to assess contributions of specific pathways. Cell proportions in muscle specimens were estimated using a deconvolution approach.

RESULTS

WGCNA revealed significant positive correlations between serum creatine kinase (CK) levels and gene modules involved in cellular respiration, phagocytosis, and oxidative phosphorylation (OXPHOS). Significant positive correlations were also observed between CK levels and proportions of CD16-positive and negative monocytes and myeloid dendritic cells. Notably, patients with DM demonstrated enrichment of complement and interferon-α and γ pathway genes compared with those with PM. Furthermore, ARS-DM demonstrated a higher proportion of Th1 cells and DEGs related to OXPHOS. Additionally, serum Krebs von den Lungen-6 levels correlated with gene modules associated with extracellular matrix and the transforming growth factor-β signaling pathway.

CONCLUSION

Our study highlights a significant involvement of monocytes in muscle damage and delineates pathologic differences among IIM subtypes. DM was characterized by complement and interferon-α and γ signaling, whereas ARS-DM was associated with OXPHOS. Distinctive gene expression variations in muscle specimens suggest that different pathologic mechanisms underlie muscle damage in each IIM phenotype.

Fine-tuning SLE treatment: the potential of selective TYK2 inhibition

In systemic lupus erythematosus (SLE), adaptive immunity is activated by the stimulation of innate immunity, leading to the development of autoreactive T cells and activation and differentiation of B cells. Cytokine signalling plays an essential role in the pathogenesis and progression of this disease. In particular, the differentiation and function of CD4+ T cell subsets, which play a central role in SLE pathology, are significantly altered by cytokine stimulation. Many cytokines transmit signals via the Janus-activated kinase (JAK)-STAT pathway, but there is no one-to-one correspondence between cytokine receptors and JAK/TYK2. Multiple cytokines activate JAK/TYK2, and multiple JAK/TYK2 molecules are simultaneously activated by a single cytokine. Therefore, the modulation of the JAK-STAT pathway has the potential to control immune responses in SLE. Although several JAK/TYK2 inhibitors are currently undergoing clinical trials, more selective drugs that can target cytokine signals according to the specific pathology of the disease are required. TYK2 inhibitors, which are involved in the signal transduction of type I interferon and interleukin-12/23 pathways and are linked to disease susceptibility genes in SLE, may have the potential to fine-tune the differentiation and function of immune cells, particularly CD4+ T cells.

The immunology of systemic lupus erythematosus

Understanding the pathogenesis and clinical manifestations of systemic lupus erythematosus (SLE) has been a great challenge. Reductionist approaches to understand the nature of the disease have identified many pathogenetic contributors that parallel clinical heterogeneity. This Review outlines the immunological control of SLE and looks to experimental tools and approaches that are improving our understanding of the complex contribution of interacting genetics, environment, sex and immunoregulatory factors and their interface with processes inherent to tissue parenchymal cells. Efforts to advance precision medicine in the care of patients with SLE along with treatment strategies to correct the immune system hold hope and are also examined.

Epigenetic signature and key transcriptional regulators of human antigen-specific type 1 regulatory T cells

Human adaptive immunity is orchestrated by effector and regulatory T (Treg) cells. Natural Tregs arise in the thymus where they are shaped to recognize self-antigens, while type 1 Tregs or Tr1 cells are induced from conventional peripheral CD4 + T cells in response to peripheral antigens, such as alloantigens and allergens. Tr1 cells have been developed as a potential therapy for inducing antigen-specific tolerance, because they can be rapidly differentiated in vitro in response to a target antigen. However, the epigenetic landscape and the identity of transcription factors (TFs) that regulate differentiation, phenotype, and functions of human antigen-specific Tr1 cells is largely unknown, hindering Tr1 research and broader clinical development. Here, we reveal the unique epigenetic signature of antigen-specific Tr1 cells, and TFs that regulate their differentiation, phenotype and function. We showed that in vitro induced antigen-specific Tr1 cells are distinct both clonally and transcriptionally from natural Tregs and other conventional CD4 + T cells on a single-cell level. An integrative analysis of Tr1 cell epigenome and transcriptome identified a TF signature unique to antigen-specific Tr1 cells, and predicted that IRF4, BATF, and MAF act as their transcriptional regulators. Using functional genomics, we showed that each of these TFs play a non-redundant role in regulating Tr1 cell differentiation, suppressive function, and expression of co-inhibitory and cytotoxic proteins. By using the Tr1-specific TF signature as a molecular fingerprint, we tracked Tr1 cells in peripheral blood of recipients of allogeneic hematopoietic stem cell transplantation treated with adoptive Tr1 cell therapy. Furthermore, the same signature identified Tr1 cells in resident CD4 + T cells in solid tumors. Altogether, these results reveal the epigenetic signature and the key transcriptional regulators of human Tr1 cells. These data will guide mechanistic studies of human Tr1 cell biology and the development and optimization of adoptive Tr1 cell therapies.