Reduced SRSF1 Expression Correlates with LCK Exon Skipping and Impaired Treg Induction in Immune Thrombocytopenia.

Splicing-mediated control of hnRNPD isoform switching by SRSF2 drives PD-L1-dependent immune evasion in gallbladder cancer

A specific protein (SRSF2) acts like a rogue editor, altering the genetic instructions of another molecule (hnRNPD) and creates a “shield” (PD-L1) on the surface of the cancer cell, effectively blinding the immune system and allowing the tumor to grow unchecked.

An Increased Circular RNA, circRNPS1, in T Cells of Ankylosing Spondylitis Patients Enhances the MEK/ERK Signaling and Inflammation Mediated by T Cell Activation via Stabilization of hnRNPK and VAV1

Disrupting the interaction between circRNPS1 and hnRNPK therefore warrants further investigation as a potential therapeutic strategy for AS.

A novel FLNA p.Pro2469Ser variant is associated with impaired T and NK cell function and immune dysregulation

ANKRD49 promotes immune evasion in lung adenocarcinoma by activating the MEF2A/PD‑L1 axis.

Non‑small cell lung cancer (NSCLC), particularly lung adenocarcinoma (LUAD), exhibits a high rate of primary resistance to immune checkpoint inhibitors, underscoring the need to decipher the molecular mechanisms of immune evasion. Here, we identify ANKRD49 as a critical regulator of PD‑L1 expression and immunosuppression in LUAD. Immunohistochemical analysis of clinical LUAD specimens revealed that high ANKRD49 expression correlates with reduced CD4+ and CD8+ T cell infiltration, increased FOXP3+ regulatory T cells, and elevated PD‑L1 levels. Functional experiments demonstrated that ANKRD49 overexpression in LUAD cells suppresses T cell cytotoxicity, promotes T cell apoptosis, and impairs granzyme B and IFN‑γ production in vitro. Mechanistically, ANKRD49 directly binds the transcription factor MEF2A via its second ankyrin repeat domain, upregulates MEF2A expression, and promotes its transcriptional activity at two specific sites within the PD‑L1 promoter. Chromatin immunoprecipitation and luciferase reporter assays confirmed that MEF2A directly activates PD‑L1 transcription in an ANKRD49‑dependent manner. In subcutaneous and metastatic mouse models, ANKRD49 overexpression accelerates tumor growth and metastasis, while PD‑L1 blockade reverses these effects and restores antitumor immunity. Collectively, our findings establish the ANKRD49-MEF2A-PD‑L1 axis as a novel driver of immune evasion in LUAD, and identify ANKRD49 ankyrin repeat domain 2 as a potential therapeutic target for overcoming immunotherapy resistance.

A distal transcribed enhancer of KRAS fine-tunes Tfh-mediated vaccine response 2308711

Enhancer RNAs (eRNAs) are noncoding transcripts from active enhancers whose functions in adaptive immunity are poorly defined. Because small changes in signaling strength can alter T cell fate and B cell help, we hypothesized that eRNAs act as rheostats for key fate decisions and signaling modules shaping antigen-induced immune responses. We integrated rRNA-depleted RNA-seq, ATAC-seq, and ChIP-seq to map transcribed enhancers in human B, CD4, and CD8 T cells. We then focused on a conserved eRNA ∼140 kb upstream of KRAS (eKRAS) and tested its function using si/shRNA, CRISPR perturbations, and phospho-signaling assays in human T cells, together with eKras—/— mice, mixed bone marrow chimeras, influenza infection, and SARS-CoV-2 mRNA vaccination with downstream cellular and serologic analyses. We catalogued and characterized ∼2,000 eRNAs in human adaptive immune cells; eKRAS was among the most highly expressed and conserved and functioned as a cis-acting enhancer of KRAS. Disruption of eKRAS reduced KRAS mRNA and attenuated RAS-ERK activation. Although eKras—/— mice developed normally, immunized mixed chimeras revealed a cell-intrinsic defect in T follicular helper (Tfh) differentiation, with impaired germinal center formation, reduced Tfh effector programs, and defective neutralizing antibody responses to protein antigens and influenza. Following SARS-CoV-2 mRNA vaccination, eKras—/— mice showed reduced class-switched anti-spike antibodies. An eKRAS-dependent Tfh transcriptional program was conserved in human blood and associated with neutralizing antibody titers after COVID-19 vaccination. We define a systematic catalog of eRNAs in human adaptive immune cells and identify a distal transcribed enhancer that fine-tunes KRAS signaling in Tfh cells to support effective vaccine responses. These findings establish eRNAs as noncoding regulators of T cell circuits controlling antibody production and nominate the eKRAS-KRAS axis as a target to optimize humoral immunity. N/A Immune Response Regulation: Molecular Mechanisms (IRM)

Proteomic insights into human induced regulatory T cells: the role of LPXN and CD160 in immune suppression.

Regulatory T cells (Treg) play a central role in maintaining immune homeostasis, and the implementation of in vitro induced Treg cells (iTreg) to control immune function has significant potential in clinical medicine. The clinical application of iTreg has been limited by their poor stability. To better define the molecular characteristics of human iTreg, we performed a data-independent acquisition proteomics, detecting over 8000 proteins and providing a quantitative comparison of their relative levels in iTreg and activated Th0 cells. Consistent with the known molecular characteristics of Treg, several Treg signature proteins, including FOXP3, IKZF4, IL2RA, CTLA4, PD-1, IKZF3, LAG3, RUNX1 and HIC1, were identified and validated using Tier 2 targeted SRM and/or qRT-PCR. Notably, Leupaxin (LPXN) level was upregulated during Treg cell differentiation. Functional studies demonstrated that LPXN-deficient cells showed impaired expression of Treg protein markers FOXP3, IKZF4 and IKZF3 and impaired suppression of effector T cells. In addition, we identified a distinct CD160+ iTreg subpopulation characterized by a distinct proteomic signature as compared to CD160- iTreg. Together, these findings provide a high-resolution proteomic landscape of human iTreg and identified a novel role of LPXN in the development and suppressive activity of iTreg.