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A PI3Kδ-Foxo1-FasL signaling amplification loop rewires CD4+ T cell signaling and differentiation

Dominic P. Golec, Pamela L. Schwartzberg and colleagues (National Institute of Allergy and Infectious Diseases (NIAID)) describe a PI3 Kinase-Foxo1-FasL signaling circuit that promotes amplified signaling and rewires transcriptional and epigenetic programs driving IFN-γ and altered T helper cell differentiation in CD4+ T cells from mice expressing an activating mutant of phosphoinositide 3-kinase delta.

Immunodeficiency LymphocyteBiology


While inputs regulating CD4+ T helper (Th) cell differentiation are well defined, the integration of downstream signaling with transcriptional and epigenetic programs that define Th lineage identity remains incompletely resolved. PI3K signaling is a critical regulator of T cell function; activating mutations affecting PI3Kδ result in an immunodeficiency with multiple T cell defects. Using mice expressing activated PI3Kδ, we found aberrant expression of proinflammatory Th1 signature genes under Th2-inducing conditions, both in vivo and in vitro. This dysregulation was driven by a PI3Kδ-IL-2-Foxo1 signaling amplification loop, fueling Foxo1 inactivation, loss of Th2 lineage restriction, and extensive epigenetic reprogramming. Surprisingly, ablation of Fasl, a Foxo1-repressed gene, normalized both Th2 differentiation and TCR signaling. BioID and imaging revealed Fas interactions with TCR signaling components, which were supported by Fas-mediated potentiation of TCR signaling that could occur in the absence of FADD. Our results highlight Fas-FasL signaling as a critical intermediate in phenotypes driven by activated PI3Kδ, thereby linking two key pathways of immune dysregulation.

Immune checkpoint inhibitor–induced myocarditis is dependent on CD8 T cell–derived TNF and TNFR2 signaling

Kathrynne Warrick, Chandrashekhar Pasare et al. show that PD-1 blockade leads to de novo priming of self-reactive CD8 T cells resulting in immune related adverse events.


Immune checkpoint inhibitors (ICIs) improve cancer survival but can trigger immune-related adverse events. Among these, fulminant myocarditis is an often fatal complication with limited therapies. We developed a mouse model employing cardiomyocyte-restricted antigen expression to define how ICIs drive cardiac autoimmunity. Combined cytotoxic T cell antigen-4 (αCTLA-4) and programmed death-1 (αPD-1) blockade uniquely induced robust expansion of antigen-specific CD8 T cells, myocardial inflammation, and lethal arrhythmias. PD-1 blockade alone permitted the priming and effector differentiation of naive autoreactive CD8 T cells, whereas concomitant CTLA-4 inhibition amplified cardiac pathology. Unexpectedly, myocardial injury was independent of perforin-mediated cytotoxicity but critically depended on T cell–derived TNF, which promoted myeloid recruitment, cytokine production, and arrhythmogenesis. Genetic ablation of CD8 T cell–derived tumor necrosis factor (TNF) or TNF receptor 2 (TNFR2) blockade prevented cardiotoxicity while preserving antitumor efficacy. These findings establish a TNF-TNFR2–driven inflammatory circuit downstream of autoreactive CD8 T cells as a central mechanism of ICI myocarditis and a strategy to uncouple cardiotoxicity from immunotherapy benefits.

AI Tool Sets New Standard in Diagnosing Rare Diseases

A new system, which consists of a large LLM and a network of agentic tools, outperformed several other models and human physicians [1].

Too rare to easily diagnose

Rare diseases can be notoriously hard to diagnose. Patients average over 5 years to receive a correct diagnosis, enduring repeated referrals, misdiagnoses, and unnecessary interventions in what is known in rare disease medicine as ‘the diagnostic odyssey’ [2]. These rare diseases, defined as conditions affecting fewer than 1 in 2000 people, collectively impact over 300 million people worldwide. About 7,000 distinct disorders of this type have been identified, with 80% of them being genetic in origin [3].

Convergence of aging- and rejuvenation-related epigenetic alterations on PRC2 targets

Rejuvenation of tissues in physiologically aging mice can be accomplished by long-term partial reprogramming via expression of reprogramming factors (Oct4, Sox2, Klf4, and c-Myc). To investigate the epigenetic determinants of partial reprogramming-mediated rejuvenation, we used whole-genome bisulfite sequencing to carry out unbiased comprehensive profiling of DNA methylation changes in skin from mice subjected to partial reprogramming, as well as young and untreated old controls. We found a striking convergence of age- and rejuvenation-related epigenetic alterations on targets of the Polycomb repressive complex 2 (PRC2), with increased DNA methylation level and entropy over these regions. Native ChIP demonstrated extensive loss of H3K27me3 in aged epidermis compared to young, partially overlapping regions with age- and rejuvenation-related DNA methylation changes. In addition, large H3K9me2-marked “LOCK” heterochromatin domains defined the boundaries for hypomethylated highly entropic regions during aging. These results are also supported by a likewise prominent enrichment of PRC2 targets in gene expression data, suggesting that PRC2 activity can modulate aging and mediate tissue rejuvenation.

Mechanical Dialogues of Life and Death: How External Molecules Entry Triggers a Chromatin‐Cytoskeleton Morphogenetic Duel in Cancer Cells

The next-generation anti-cancer therapeutics must disrupt intracellular mechanics, efficiently eradicating cancer cells, rather than simply intoxicating them. We evaluate the mechanism of action of PCMS, a PAMAM-based supramolecule that eradicates cancer cells by reorganizing their internal mechanics rather than their genes. Once internalized, PCMS self-assembles into a perinuclear ring that severs nucleus-cytoskeleton communication. We observed PCMS’s dual-intelligent mechanisms of action: Cytoskeletal rescue, where actin-microtubule filaments move towards the PCMS ring, treating it as a surrogate plasma membrane, attempting to restore vesicular trafficking; Nuclear counter-expansion, where chromatin-lamina condensates undergo stepwise viscoelastic transitions that push the nuclear envelope outward to reestablish membrane contact. These contradictory forces amplify mechanical stress, driving super-critical strain and nuclear lysis without broad transcriptional modulations. By geometry alone, PCMS collapses the actin-microtubule-nucleus continuum and turns the cell’s adaptive machinery into its own executioner. The discovery that life and death decisions can be reprogrammed through spatial conflict establishes a paradigm of mechanical deception, inaugurating a new class of cellular adaptive feedback-targeted mechanotherapeutics that overcome resistance by exploiting the cell’s own morphogenetic logic.

Abstract: A therapeutic target for terminating the long-lived autoimmune response!

Maureen A. Su find the epigenetic regulator UTX complexes with transcription factors TCF1 and STAT3 to promote pathogenicity of long-lived, stem-like progenitor T cells in models of type 1 diabetes (T1D)


1Department of Microbiology, Immunology, and Molecular Genetics, UCLA David Geffen School of Medicine, Los Angeles, California, USA.

2Department of Pediatrics and.

3Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

DOT1L provides transcriptional memory through PRC1.1 antagonism

Genetic off switch for cancer face_with_colon_three #cancer #cure


Neville, Ferguson et al. show that non-canonical Polycomb repressive complex 1.1-mediated gene silencing is antagonized by DOT1L and is required for the therapeutic efficacy of Menin and DOT1L inhibitors in mixed-lineage leukaemia.

Identifying aggressive prostate cancer with multi-omics

Prostate cancer often develops very slowly. For the vast majority, this is a disease that you live well with, without the need for treatment, but some get an aggressive variant with recurrence of cancer even after surgery. The disease behaves very differently from patient to patient. Understanding what makes the cancer aggressive is crucial for better diagnostics and treatment, says the author.

Aggressive cancer has its own gene expression: The researchers identified a pattern in the gene expression of the tumor itself in prostate tissue in patients with a high risk of recurrence and spread. This signature can become a new tool for distinguishing between patients who need intensive care and those who can manage with less intensive follow-up.

Inflammation of apparently healthy tissue: Signs of inflammation and changes in metabolic processes were also found in the normal tissue close to the cancerous tumor. These glands had high activity of neurotransmitters that attract immune cells, and an increased occurrence of a cell type that can trigger inflammatory reactions. At the same time, the levels of important substances had decreased, suggesting that the gland had lost its normal function.

“Aggressive prostate cancer appears to be associated with inflammation in the area around the cancer cells, combined with specific genetic signatures and metabolic changes in the prostate tissue. This knowledge can provide better methods for early identification of patients at high risk,” says the author. ScienceMission sciencenewshighlights.


The research lays a foundation for the possibility that aggressive prostate cancer can probably be detected through a few drops of semen or blood in the long term.

Prostate cancer is the most common form of cancer among men in Western countries.

Germline mutations in DICER1 and DGCR8 can lead to a range of thyroid conditions

Here, Barbara Rivera & team report on the benign-to-malignant progression route in DICER1/DGCR8-thyroid lesions, identifying a DICER1-cancer epi-signature using multi-omic profiling:

The image depicts a thyroid lesion from a sporadic DICER1 case with immunofluorescent staining for pan-cytokeratin (green) and vimentin (red). Enclosed areas represent selected regions of interest.


1Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona, Spain.

2Genetics Program, Faculty of Biology, and.

3Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.

Comparative single-cell lineage bias in human and murine hematopoietic stem cells

A comparative single-cell analysis reveals similarities and differences in lineage bias between human and murine hematopoietic stem cells. This work deepens our understanding of how lineage commitment is regulated across species and provides a valuable framework for translating insights from mouse models to human hematopoiesis.


The commitment of hematopoietic stem cells (HSC) to myeloid, erythroid, and lymphoid lineages is influenced by microenvironmental cues, and governed by cell-intrinsic and epigenetic characteristics that are unique to the HSC population. To investigate the nature of lineage commitment bias in human HSC, mitochondrial single-cell assay for transposase-accessible chromatin (ATAC)-sequencing was used to identify somatic mutations in mitochondrial DNA to act as natural genetic barcodes for tracking the ex vivo differentiation potential of HSC to mature cells. Clonal lineages of human CD34+ cells and their mature progeny were normally distributed across the hematopoietic lineage tree without evidence of significant skewing. To investigate commitment bias in vivo, mice were transplanted with limited numbers of long-term HSC (LT-HSC). Variation in the ratio of myeloid and lymphoid cells between donors was suggestive of a skewed output but was not altered by increasing numbers of LT-HSC. These data suggest that the variation in myeloid and lymphoid engraftment is a stochastic process dominated by the irradiated recipient niche with minor contributions from cell-intrinsic lineage biases of LT-HSC.

Hematopoietic stem cells (HSC) are classically considered to have the capacity for complete regeneration of the hematopoietic compartment. More recent analyses indicate additional complexity and heterogeneity in the HSC compartment, with lineage-restricted or lineage-biased HSC considered a feature of mammalian hematopoiesis.1–13 A partial differential equation model to study relationships between hematopoietic stem and progenitor cells (HSPC) emphasizes that myeloid bias cannot be accounted for solely by short-term HSC bias during inflammation but rather involves a combination of HSC and progenitor cell biases.14 Central to the concept of lineage bias is an assumption that cells used for studying HSC commitment are HSC and not multipotent progenitors or lineage-committed progenitors. Changes in differentiation of cells downstream of the long-term HSC (LT-HSC) must also be evaluated when considering the potential lineage bias of a LT-HSC.

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