Lysosomes are essential regulators of cellular homeostasis. Emerging evidence positions lysosomes as both vulnerable targets and active drivers of ageing biology. During ageing, lysosomes exhibit impaired biogenesis, defective acidification, reduced hydrolytic activity and compromised membrane integrity. These defects impair the clearance of damaged organelles and macromolecules and promote cellular stress responses, inflammageing and senescence, causing age-dependent functional decline across tissues. Lysosomal dysfunction has been increasingly linked to age-related diseases, including neurodegeneration, cardiometabolic disorders and increased susceptibility to infection, among others. Thus, lysosomal dysfunction is a hallmark of ageing that drives age-related pathology. Here we review recent progress in lysosomal biogenesis and quality control, discuss how lysosomes intersect with fundamental ageing mechanisms and evaluate emerging therapeutic strategies that target lysosomes to promote healthy ageing and potentially ameliorate age-associated pathologies.

Coronary atherosclerosis underlies life-threatening conditions such as myocardial infarction and stroke, yet its cellular dynamics remain incompletely understood. Here, through single-cell RNA sequencing of 27,941 cells from 56 human coronary segments, we constructed a disease-stage-resolved cellular atlas, revealing pathological remodelling of endothelial cells (ECs) into a progenitor-like state (EC5[SLCO4A1+]) with low expression of canonical EC dysfunction signatures. EC5[SLCO4A1+] abundance increased with atherosclerotic stage, and its emergence is driven by PRDM15 through direct transcriptional activation. Analysis of the EC5[SLCO4A1+] interaction network revealed extensive crosstalk with immune cell types, the interaction between which contributed to atherosclerotic progression. Endothelial overexpression of Prdm15 in vivo exacerbated atherosclerosis, while its suppression ameliorated the disease phenotype, with diminished EC5[SLCO4A1+]-like cells and immune infiltration. Our findings underscore the central role of EC subtype remodelling in the progression of human coronary atherosclerosis and reveal tractable targets for therapeutic intervention.

Early embryogenesis is accompanied by dynamic epigenetic modifications. Although such dynamics are important in cell intrinsic regulation of gene expression, their extrinsic roles in mediating intercellular communication during early embryogenesis are less understood. Here, using the dTAG system, we reveal previously underappreciated stage-specific functions of PRC2 in regulating preimplantation and primordial germ cell (PGC) development. We demonstrate that PRC2 plays important roles in regulating maternal-to-zygotic transition and epiblast formation. By systematically analysing H3K27me3 and H3K4me3 dynamics, we redefine the timing of bivalency establishment and uncover a stepwise mechanism governing bivalency acquisition in early embryogenesis. Moreover, PRC2 regulates proper PGC numbers in the epiblast by controlling Esrrb expression in the extraembryonic ectoderm. Thus, our study uncovers a previously unknown cell-autonomous function of PRC2 in preimplantation development and its non-cell-autonomous impact in PGC number regulation, both through interplays between epigenetic-epigenetic and epigenetic-transcription factors networks.

Nucleotides are essential for life, serving not only as the building blocks of the genome but also as cellular energy providers, metabolic cofactors and signalling molecules. To sustain cellular function and proliferation, cells must continuously generate, recycle and precisely balance nucleotide pools in response to fluctuating metabolic and environmental demands. Nucleotide metabolism is therefore not a static biosynthetic pathway, but a dynamic system tightly integrated with cell signalling and physiology. Here we highlight the regulatory logic of nucleotide metabolism, from acute post-translational regulation to transcriptional scaling, feedback control and higher-order spatial organization into multi-enzyme assemblies and filaments. Through the lens of human genetic disorders and cancer, we examine how nucleotide depletion, pool imbalance or intermediate toxicity produce striking tissue-selective pathologies. Together, these principles position nucleotide metabolism as a central regulatory axis linking cellular metabolism, signalling and fate in health and disease.

Regulation of the actin cytoskeleton by actin-binding proteins is essential for cellular homeostasis, and the mode of actin binding determines the activity of actin-binding proteins. Here we identify a 'short linear actin filament-binding motif' (SFM) based on the cryo-electron microscopy structure of the ITPKA-actin filament complex. Using the computational pipeline SLiMFold, we discovered 103 human proteins containing SFMs with diverse cellular roles. Phylogenetic analysis suggests that SFMs arose de novo and are conserved across eukaryotes, exhibiting actin filament-binding affinities of 2-12 µM. Critical residues mediating binding and modulating affinity were defined, and the cryo-electron microscopy structures of two SFM-actin filament complexes revealed that SFM binding decreases actin-filament stiffness. These findings indicate that SFMs regulate actin-filament conformation and serve as anchoring modules that connect actin dynamics to a broad variety of cellular functions, providing a framework for understanding the actin-associated roles of numerous proteins.

Cells under high confinement migrate efficiently in low-adhesion environments by forming stable, polarized, hydrostatic pressure-driven leader blebs. Here we investigated the basis of polarized bleb morphology in metastatic melanoma cells migrating under low-adhesive and highly confined microenvironments. Using high-resolution live imaging, molecular perturbations and biosensors, we show that EGF signalling through PI3K stabilizes and maintains polarized leader blebs. EGFR and PI3K activities form a gradient within leader blebs that decreases from rear to front, promoting phosphatidylinositol 3,4,5-trisphosphate and Rac1-GTP accumulation at the bleb rear, whereas phosphatidylinositol 4,5-bisphosphate and RhoA-GTP concentrate at the bleb tip, the inverse of the organization observed in integrin-dependent mesenchymal migration. Optogenetic disruption of this gradient triggers bleb retraction, underscoring its functional importance. Mathematical modelling and experiments identified a mechanism whereby during bleb initiation, CD44 and ERM proteins restrict EGFR mobility within a membrane-apposed cortical actin meshwork at the bleb rear, establishing the EGFR-PI3K-Rac gradient. Together, these findings define the biophysical and molecular mechanisms that underlie polarity in bleb-based migration and highlight how alternative spatial organization of signalling modules supports distinct migration modes in different microenvironments.

The anterior insular cortex (AIC) is a critical hub integrating exteroceptive and interoceptive information into high-order cognition, yet its neural basis remains incompletely understood. Here, by combining whole-cell-based single-cell transcriptomics with Patch-seq recordings, we resolved and characterized 78 detailed cell types in the macaque AIC, revealing the diversity and specialization of this region in cell type, connectivity profile, signal-processing strategy and metabolic characteristics. Among these, we identified two transcriptomically and morphoelectrically defined von Economo neuron (VEN) subtypes, DSG2-expressing VEN-L and POC5-expressing VEN-S, transcriptomically relating to extratelencephalic and corticothalamic projection neurons, respectively. We also uncovered a previously underappreciated signal-processing strategy by VENs, whereby the geometry of the dendrite-originating axon reshapes action potential dynamics and enhances somatic responsiveness to deep-layer synaptic inputs. Our multimodal atlas establishes a molecular and functional framework for investigating the circuit principles underlying cognitive processes in the primate AIC.

Lipid-binding domains, traditionally isolated from natural proteins, are essential tools for probing membrane lipid dynamics and specialized cellular compartments. Despite diverse applications, a general strategy for their engineering remains elusive. Here we present a robust and high-throughput method for monitoring protein-lipid interactions, named the cell surface liposome binding (CLiB) assay. Using the assay, we conducted directed evolution of the PX domain from SnxA, isolating high-affinity variants specific for phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). Combining the CLiB assay with next-generation sequencing enabled parallel analysis of >6,000 clones, comprehensively identifying key residues critical for lipid binding. An engineered variant, PX-SnxA[GV], functioned as a lipid biosensor in yeast and mammalian cells, visualizing PI(3,5)P2-enriched membrane subdomains upon hyperosmotic shock and during microautophagy, thereby suggesting localized PI(3,5)P2 synthesis within spatially restricted regions. This study provides a framework for on-demand generation of lipid-binding probes, facilitating the discovery of membrane compartments characterized by unique lipid compositions.