N Nature Immunology · Sep 29, 2025 Chemotherapy-induced CA-repeat DNA fragments in breast cancer trigger antitumor immune responses Damage-associated molecular patterns generated by cancer treatment can modulate antitumor immunity, but the underlying mechanisms of this effect are unclear. Here we show that CA-enriched DNA fragments resulting from DNA-damaging chemotherapy in MSH2-low tumors preferentially bind cGAS with strong affinity and form biomolecular condensates by phase separation in the cytoplasm, resulting in antitumor immunity. However, classical CA-poor DNAs released from MSH2-high tumor cells engage AIM2, resulting in immunosuppression by upregulating PD-L1 and IDO. Intratumoral administration of CA-rich DNA fragments enhanced antitumor immunity in syngrafted PyMT tumors. Clinically, CA-rich DNA abundance in breast cancer following chemotherapy was associated with increased tumor-antigen-reactive T cells and better chemotherapeutic responses. Therefore, different tumor DNA fragments can trigger opposing immune responses depending on their preference for differential sensors. This study highlights another mechanistic link between genome instability and immune modulation and the therapeutic potential of CA-rich DNAs to enhance antitumor immunity. Adjuvants Cancer therapy Tumour immunology Cancer Immunology Mouse Human Drug Development
N Nature Immunology · Sep 24, 2025 A single-cell and spatial genomics atlas of human skin fibroblasts reveals shared disease-related fibroblast subtypes across tissues Fibroblasts sculpt the architecture and cellular microenvironments of various tissues. Here we constructed a spatially resolved atlas of human skin fibroblasts from healthy skin and 23 skin diseases, with comparison to 14 cross-tissue diseases. We define six major skin fibroblast subtypes in health and three that are disease-specific. We characterize two fibroblast subtypes further as they are conserved across tissues and are immune-related. The first, F3: fibroblastic reticular cell-like fibroblast (CCL19+CD74+HLA-DRA+), is a fibroblastic reticular cell-like subtype that is predicted to maintain the superficial perivascular immune niche. The second, F6: inflammatory myofibroblasts (IL11+MMP1+CXCL8+IL7R+), characterizes early human skin wounds, inflammatory diseases with scarring risk and cancer. F6: inflammatory myofibroblasts were predicted to recruit neutrophils, monocytes and B cells across multiple human tissues. Our study provides a harmonized nomenclature for skin fibroblasts in health and disease, contextualized with cross-tissue findings and clinical skin disease profiles. Cancer Immunological disorders Immunology Immunology Single-cell Genomics Human Clinical
N Nature Immunology · Sep 15, 2025 A spatial map of MAPK-activated immunosuppressive myeloid populations in pediatric low-grade glioma Pediatric low-grade gliomas (pLGGs) are mitogen-activated protein kinase (MAPK) pathway-activated brain tumors prevalent in children and are associated with morbidity despite favorable survival. Here using imaging mass cytometry, we spatially characterized at the single-cell level the tumor microenvironment (TME) of 120 pLGG cases, considering age, molecular drivers, brain location and tumor subtype. Our analysis identified myeloid cells—including resident microglia and bone marrow-derived macrophages—as the predominant immune population in the TME, particularly in optic pathway tumors. Additionally, we discovered an immune signature predictive of progression-free survival. Spatial analysis identified specific cellular interactions, notably myeloid–myeloid contacts and macrophage-enriched regions harboring MAPK-activated, TIM-3+myeloid cells, suggesting an immunosuppressive TME. Our study provides a comprehensive resource on the immune landscape of these pLGGs and underscores the immunosuppressive role of diverse myeloid infiltrates. These findings also indicate that combining TIM-3 blockade with MAPK inhibition might be a promising therapeutic strategy to target both the TME and oncogenic MAPK activation in pLGG tumors. Cancer therapy Imaging the immune system Tumour immunology Cancer Immunology Single-cell Human Drug Development
N Nature Immunology · Aug 18, 2025 Loss of YTHDF2 enhances Th9 programming and CAR-Th9 cell antitumor efficacy CD4+T cells differentiate into various subsets, including T helper 1 (Th1), Th2, Th9, Th17 and regulatory T (Treg) cells, which are essential for immune responses and cancer immunotherapy. However, the role of RNAN6-methyladenosine (m6A) modification in this differentiation is unclear. Here we show that YTHDF2, an important m6A reader protein known to destabilize m6A-modified mRNA, negatively regulates Th9 cell differentiation. Ablation ofYthdf2in both mouse and human naive CD4+T cells promotes Th9 differentiation by stabilizingGata3andSmad3mRNA under interleukin-4 (IL-4) and transforming growth factor β (TGF-β) signaling, respectively.Ythdf2-deficient Th9 cells produce increased amounts of IL-9 and IL-21, leading to increased tumor infiltration and cytotoxicity by CD8+T cells and natural killer (NK) cells, thereby improving antitumor activity compared with wild-type Th9 cells. Moreover, YTHDF2 depletion in CAR-Th9 cells enhances their immune activation, reduces their terminal differentiation and augments their antitumor efficacy. Targeting YTHDF2 is thereby a promising strategy to enhance Th9 and CAR-Th9 cell-based cancer immunotherapies. Cancer immunotherapy CD4-positive T cells Lymphocyte differentiation Immunology Cancer Mouse Human Drug Development
