Cell最新文献

Hepatitis D-like satellite viruses, known as deltaviruses, have been recently discovered in a wide range of animals. These viruses are thought to expropriate glycoproteins from helper viruses to form infectious particles. Here, we challenge this paradigm and demonstrate that deltaviruses are packaged within helper virus particles, using them as viral Trojan Horses for cell entry. By leveraging orthogonal electron and optical super-resolution microscopy, we visualize deltaviruses enclosed within virions from rhabdo-, herpes-, and arenavirus families. We show that this conserved hitchhiking mechanism ensures concomitant deltavirus-helper virus spread, thereby promoting the dissemination of deltaviruses, broadening their host range, and expanding their tropism. Our findings reveal a previously unrecognized mode of viral transmission, providing a framework to investigate overlooked deltavirus infections outside of the human liver.

Therapeutic delivery to the brain after stroke is limited by the blood-brain barrier. In this issue of Cell, Gao et al. bypass this obstacle by harnessing skull bone marrow immune cells to deliver drug-loaded nanoparticles to injured brain regions, improving outcomes and revealing a feasible translational strategy for targeted CNS therapy.

Rosacea, an inflammatory skin disorder, poses a dilemma owing to limited effectiveness of treatments for pathological vasodilation-mediated erythema. Here, we identify oxoglutaric acid (α-KG) as a rosacea-associated metabolite elevated in patients and correlated with erythema severity. Exogenous α-KG administration ameliorates rosacea-like manifestations in murine models. Mechanistically, α-KG activates OXGR1, a vascular smooth muscle cell (VSMC)-enriched G protein-coupled receptor (GPCR) to induce Gq signaling and enhance MYL9 phosphorylation, promoting VSMC contraction and limiting vasodilation. Cryo-electron microscopy (cryo-EM) structures of OXGR1-Gq complexes bound to α-KG or itaconate reveal a specific bipartite-acid pocket recognizing its endogenous agonist and an activation mechanism distinct from classical GPCRs. Building on these structures, we developed A-1, a synthetic selective OXGR1 agonist that mitigates erythema and inflammation with efficacy comparable to first-line therapy while offering enhanced safety in rosacea-like models. These findings link a metabolite to vascular dysfunction and nominate OXGR1 agonism for precision treatment of erythema and vascular disorders.

Aggregation of the protein tau defines tauopathies, the most common age-related neurodegenerative diseases, which include Alzheimer's disease and frontotemporal dementia. Specific neuronal subtypes are selectively vulnerable to tau aggregation, dysfunction, and death. However, molecular mechanisms underlying cell-type-selective vulnerability are unknown. To systematically uncover the cellular factors controlling the accumulation of tau aggregates in human neurons, we conducted a genome-wide CRISPRi screen in induced pluripotent stem cell (iPSC)-derived neurons. The screen uncovered both known and unexpected pathways, including UFMylation and GPI anchor biosynthesis, which control tau oligomer levels. We discovered that the E3 ubiquitin ligase CRL5^SOCS4 controls tau levels in human neurons, ubiquitinates tau, and is correlated with resilience to tauopathies in human disease. Disruption of mitochondrial function promotes proteasomal misprocessing of tau, generating disease-relevant tau proteolytic fragments and changing tau aggregation in vitro. These results systematically reveal principles of tau proteostasis in human neurons and suggest potential therapeutic targets for tauopathies.

Insulating sheaths of myelin accelerate neuronal communication in the mammalian brain. Oligodendrocytes that produce myelin are generated throughout life to gradually increase myelin coverage, but these dynamics have not been defined brain-wide across the lifespan. We developed a cellular mapping pipeline involving tissue clearing, lightsheet microscopy, and AI-assisted analysis to identify the precise location of millions of oligodendrocytes and assess regional myelin density in the mouse brain. These atlases revealed the diversity of oligodendrocyte patterning, which was consistent between brain hemispheres, individuals, and sexes but displayed both age- and region-specific differences. Integration of these atlases with transcriptomic and ultrastructural datasets highlighted underlying mechanisms that may control this patterning. In models of demyelination and disease, we identified regions of enhanced oligodendrocyte resilience and vulnerability and white matter injury near β-amyloid plaques, demonstrating the utility of this pipeline for defining brain-wide oligodendrocyte dynamics in both health and disease.

Higher organisms spread external stimuli from the perceptive tissues to the whole body to achieve systemic responses. In plants, guard cells sense pathogens and close stomata to prevent their entry. We observed that pathogen-infected local leaves transmit the danger status to uninfected distal systemic leaves and trigger their stomatal closure as a global defense termed systemic stomatal immunity (SSIM). The underlying mobile signals remain unknown. Here, we report that an upstream open reading frame (uORF)-encoded systemic stomatal immune conductor (USIC) acts as a long-distance mobile peptide inducing SSIM. In local leaves, USIC increases upon pathogen/pattern signals and is secreted into the apoplast for long-distance transport. In systemic leaves, USIC is perceived by the cell surface SUCROSE-INDUCED RECEPTOR KINASE 1 (SIRK1)-KINASE 7 (KIN7) receptor complex and induces METACASPASE 4 (MC4)-mediated KIN7 cleavage. KIN7 associates with proton pumps/aquaporins to regulate stomatal closure. This study reveals a systemic signaling mechanism whereby an uORF-encoded mobile signal and its receptor pathway activate SSIM.

Approximately one-third of clinical drugs mediate their therapeutic effects through G protein-coupled receptors (GPCRs), highlighting their immense therapeutic relevance. Novel approaches to modulate GPCR activity have the potential to yield unique pharmacological profiles. Conventionally, the G protein and β-arrestin signaling pathways downstream of GPCRs have been viewed as mutually exclusive. Using the in-house developed survival pressure selection (SPS) method, a high-throughput platform for GPCR agonist discovery, we identified an allosteric ligand that stabilizes a GPCR-G protein-β-arrestin megacomplex, thereby mediating sustained receptor signaling following internalization. Remarkably, this compound, atazanavir, exhibits pan-receptor activation across multiple family A GPCRs, including GPR119, β₁AR, and β₂AR, demonstrating the broad applicability of this regulatory mechanism. This discovery uncovers a distinct mechanism of GPCR regulation, opening alternative avenues for the development of therapeutics targeting GPCRs.