The innate immune sensor AIM2 detects cytosolic DNA and initiates inflammatory responses, yet its activation mechanism remains incompletely understood. Here, we show that AIM2 undergoes liquid–liquid phase separation upon DNA binding, forming dynamic condensates both in vitro and in cells. These condensates serve as platforms for inflammasome and PANoptosome assembly, promoting immune activation across multiple pathways. Direct structural determination from condensates reveals the assembly of active-form ASC filaments. Mechanistically, liquid-phase condensation is governed by multivalent interactions involving different AIM2 domains, including previously uncharacterized regions and species-specific elements. In vitro and in vivo assays show that mutants specifically disrupting condensation impair immune complex assembly, cell death initiation, antimicrobial defense, and intestinal homeostasis. Moreover, AIM2-DNA condensates function as regulatory hubs targeted by host- and pathogen-derived factors to balance immune homeostasis or facilitate immune evasion. These findings establish liquid-phase condensation as a fundamental mechanism of AIM2 activation and a potential therapeutic target.

Breast cancer is the most frequently diagnosed cancer, with metastasis accounting for the majority of cancer-related deaths. The mechanisms of early-stage breast cancer metastasis to regional immune sites like lymph nodes remain elusive. Here, we performed an in-depth proteomic and phosphoproteomic analyses of a substantial series of breast cancer samples, alongside genomic and transcriptomic evaluations. This cohort encompasses 195 specimens: 65 primary breast tumors, their corresponding normal tissues, and metastatic axillary lymph nodes. We offer an overview of the molecular alterations at the transcriptomic, proteomic, and phosphoproteomic levels during lymph node metastasis. Notably, the findings indicate that regional lymph node metastasis is primarily influenced by proteomic and phosphoproteomic alterations, rather than genomic or transcriptomic changes. We found that ANGPTL4 and HMGB1 could serve as biomarkers of lymph node metastasis. Data analysis and cell experiments involving silencing of the alternative splicing (AS) factor HNRNPU demonstrated that AS plays a significant role in modulating protein expression, phosphorylation profiles, and cell proliferation. The key phosphorylation sites, including MARCKSL1-S104 and FKBP15-S320, as well as the upstream kinase PRKCB, were identified as playing crucial roles in breast cancer lymph node metastasis. Targeted intervention of the kinase PRKCB resulted in effectively suppressing the proliferation and metastasis of breast cancer tumor cells. Immune profiling analysis and experimental validation of breast cancer cell co-cultured with CD8⁺ T cell reveals correlations between phosphorylation of MARCKSL1-S104 and FKBP15-S320 with immune checkpoint PD-L1 expression, and their impact on tumor cell apoptosis, suggesting a potential mechanism of immune evasion in metastasis. This study systematically characterizes the molecular landscape and features of primary breast tumors and their matched metastatic lymph nodes. These insights enhance our understanding of early-stage breast cancer metastasis and may pave the way for improved diagnostic tools and targeted therapeutic strategies.

Aging of the male reproductive system is characterized by declining fertility, with epididymal dysfunction being a critical yet poorly understood contributor. Through a multimodal analysis in non-human primates that integrated histology and transcriptomics, we delineated a coherent epididymal aging phenotype encompassing epithelial senescence, chronic inflammation, fibrosis, and functional decline. Single-nucleus transcriptomics revealed principal cells (PCs) as the predominant and most transcriptionally perturbed epithelial cell type. Within PCs, the longevity-associated transcription factor FOXO1 was markedly downregulated with age. Functional studies in human epididymal epithelial cells demonstrated that FOXO1 deficiency drives cellular senescence. Mechanistically, FOXO1 transcriptionally activates LHX1, and this axis is essential for counteracting senescence. Furthermore, intervention with senescence-resistant mesenchymal progenitor cells or their exosomes mitigated epididymal aging phenotypes and restored FOXO1 expression in vivo and in vitro. Our study establishes the FOXO1-LHX1 axis as a key protective pathway against primate epididymal aging, providing mechanistic insights and potential therapeutic targets for preserving male reproductive health.

The acquisition of totipotency requires transcriptional activation of endogenous retroviruses (MERVL/HERVL) and zygotic genome activation (ZGA) related genes, yet the molecular mechanisms linking chromatin architecture to this process remain elusive. Here, we demonstrate that mouse Dux and human DUX4, double homeobox transcription factors essential for totipotency, form liquid–liquid phase-separated (LLPS) condensates through conserved arginine residues within intrinsically disordered regions (IDRs) in the Homeobox domain. These condensates recruit CBP/p300 and CTCF to establish super-enhancers (SEs) at MERVL/MT2 loci, enabling H3K27ac deposition and chromatin accessibility. Hi-C analysis revealed that DUX-driven phase separation facilitates 3D genome reorganization, including de novo formation of enhancer-promoter loops and TAD boundary shifts. Disruption of LLPS (DUX^R70A) abolished SE assembly, transcriptional activation, and embryonic chimerism. Strikingly, human DUX4 required phase separation for both myotoxic gene activation and cytotoxicity in facioscapulohumeral muscular dystrophy (FSHD) models. Our study establishes a paradigm wherein phase separation integrates transcriptional control with 3D genome remodeling to license totipotency, with direct implications for developmental biology and disease therapy.