Reduced chromatin accessibility to CD4 T cell super-enhancers encompassing susceptibility loci of rheumatoid arthritis

Mitochondrial Control of Proteasomal Psmb5 Drives the Differentiation of Tissue-Resident Memory T Cells in Patients with Rheumatoid Arthritis

OBJECTIVE

To explore T cell-intrinsic mechanisms underpinning the mal-differentiation of tissue-resident memory T (Trm) cells in patients with rheumatoid arthritis (RA).

METHODS

Circulating T cells from patient with RA and healthy individuals were used for Trm cell differentiation. The role of Hobit in Trm differentiation was investigated through targeted silencing experiments. Psmb5 expression regulation was explored by identifying BRD2 as a key transcription factor, with the interaction validated through chromatin immunoprecipitation-quantitative polymerase chain reaction. The impact of BRD2 succinylation on Trm differentiation was examined by manipulating succinyl-CoA levels in T cells. Humanized NSG chimeras representing synovitis provided insights into Trm infiltration in RA synovitis and were used for translational experiments.

RESULTS

In patients with RA, a notable predisposition of CD4+ T cells toward differentiation into Trm cells was observed, demonstrating a positive correlation with the disease activity score 28. Remarkably, Hobit was a pivotal facilitator in the formation of RA CD4+ Trm cells. Mechanistic studies unveiled the dysregulation of proteasomal Psmb5 in T cells of patients with RA as the key factor contributing to elevated Hobit protein levels. The deficiency of proteasomal Psmb5 was intricately linked to BRD2, with succinylation exerting a significant impact on Psmb5 transcription and Trm cell differentiation. This heightened BRD2 succinylation was attributed to elevated levels of mitochondrial succinyl-CoA in RA T cells. Consequently, targeting succinyl-CoA within CD4+ T cells controlled the inflammation of synovial tissues in humanized chimeras.

CONCLUSION

Mitochondrial succinyl-CoA fosters the succinylation of BRD2, resulting in compromised transcription of proteasomal Psmb5 and the differentiation of Trm cells in RA.

Hepatocellular carcinoma-specific epigenetic checkpoints bidirectionally regulate the antitumor immunity of CD4 + T cells

Hepatocellular carcinoma (HCC) is a highly malignant tumor with significant global health implications. The role of CD4+ T cells, particularly conventional CD4+ T cells (Tconvs), in HCC progression remains unexplored. Furthermore, epigenetic factors are crucial in immune regulation, yet their specific role in HCC-infiltrating Tconv cells remains elusive. This study elucidates the role of MATR3, an epigenetic regulator, in modulating Tconv activity and immune evasion within the HCC microenvironment. Reanalysis of the scRNA-seq data revealed that early activation of CD4+ T cells is crucial for establishing an antitumor immune response. In vivo and in vitro experiments revealed that Tconv enhances cDC1-induced CD8+ T-cell activation. Screening identified MATR3 as a critical regulator of Tconv function, which is necessary for antitumour activity but harmful when overexpressed. Excessive MATR3 expression exacerbates Tconv exhaustion and impairs function by recruiting the SWI/SNF complex to relax chromatin in the TOX promoter region, leading to aberrant transcriptional changes. In summary, MATR3 is an HCC-specific epigenetic checkpoint that bidirectionally regulates Tconv antitumour immunity, suggesting new therapeutic strategies targeting epigenetic regulators to enhance antitumour immunity in HCC.

CD305 participates in abnormal activation of memory CD4+ T cells in patients with RA and attenuates collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that mainly affects the joints. Studies have shown that memory CD4+ T cells play an important role in the pathogenesis of RA. This study investigated the expression and function of CD305 on human memory CD4+ T cells and the effects of CD305 activating antibody on collagen-induced arthritis. The results showed that CD305 expression was significantly decreased on circulating memory CD4+ T cells from patients with RA and its mean fluorescence intensity (MFI) was negatively correlated with DAS28. Moreover, CD305 inhibited the activation of memory CD4+ T cells by down-regulating CD69 and CD25 and the production of IFN-γ, IL-4, and IL-17A induced by anti-CD3/CD28 antibodies. In addition, activation of CD305 inhibited the severity of disease in collagen-induced arthritis. In summary, CD305 reduction may mediate the excessive activation of memory CD4+ T cells and participate in the development of RA. It can be used as a predictive marker of disease activity and has potential medicinal value in the treatment of RA.

Rheumatoid arthritis: pathogenesis and therapeutic advances

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the unresolved synovial inflammation for tissues-destructive consequence, which remains one of significant causes of disability and labor loss, affecting about 0.2-1% global population. Although treatments with disease-modifying antirheumatic drugs (DMARDs) are effective to control inflammation and decrease bone destruction, the overall remission rates of RA still stay at a low level. Therefore, uncovering the pathogenesis of RA and expediting clinical transformation are imminently in need. Here, we summarize the immunological basis, inflammatory pathways, genetic and epigenetic alterations, and metabolic disorders in RA, with highlights on the abnormality of immune cells atlas, epigenetics, and immunometabolism. Besides an overview of first-line medications including conventional DMARDs, biologics, and small molecule agents, we discuss in depth promising targeted therapies under clinical or preclinical trials, especially epigenetic and metabolic regulators. Additionally, prospects on precision medicine based on synovial biopsy or RNA-sequencing and cell therapies of mesenchymal stem cells or chimeric antigen receptor T-cell are also looked forward. The advancements of pathogenesis and innovations of therapies in RA accelerates the progress of RA treatments.