Cell Discovery最新文献

SARS-CoV-2 infection has raised significant concerns regarding its impact on assisted reproductive technology. We found that oocyte retrieval during acute SARS-CoV-2 infection significantly reduced the rates of good-quality blastocyst formation, but the underlying molecular mechanisms remain poorly understood. To address this, we investigated the effects of maternal acute SARS-CoV-2 infection on preimplantation embryo development and the early offspring hematopoietic system. Using single-cell RNA sequencing (scRNA-seq), we identified developmental delays in morphologically normal blastocysts from infected mothers, characterized by prolonged expression of zygotic genome activation-related genes, downregulation of mTORC1 signaling, and altered energy metabolism, including suppressed oxidative phosphorylation (OXPHOS) and enhanced glycolysis. We further revealed that maternal acute infection induced abnormal methylation/demethylation patterns in preimplantation embryos. To assess the potential long-term impact on offspring, we conducted integrated multi-tissue analyses, including bulk RNA-seq and genome-wide DNA methylation profiling of placental tissues, along with scRNA-seq of umbilical cord blood (UCB) cells from neonates delivered by SARS-CoV-2-infected mothers. Neonates exhibited elevated levels of inflammatory cytokines and an increased abundance of monocytes, indicating an activated myelopoiesis response. In addition, hematopoietic stem and progenitor cells (HSPCs) from UCB showed reduced OXPHOS activity and a skewed differentiation bias toward the myeloid lineage, potentially impacting long-term immune function. Collectively, these findings reveal that maternal acute SARS-CoV-2 infection impairs preimplantation embryo development and leaves a lasting imprint on offspring hematopoietic health through dysregulated energy metabolism, epigenetic modifications, and altered immune responses.

Receptor-like kinases (RLKs) reside on the cell surface and recognize apoplastic colonization by plant-infecting microbes to initiate immune responses. Whether RLKs can also recognize intracellular colonization by viruses to activate antiviral defense mechanisms in plants remains unknown. Here, we report the identification and characterization of a trans-Golgi network/early endosome (TGN/EE)-localized RLK that recognizes viral proteins and inhibits infection in rice. OsVIRK1, a cysteine-rich receptor-like kinase, promotes rice resistance to rice stripe virus (RSV), one of the most devastating viruses of rice. OsVIRK1 transcription is induced in RSV-infected rice, and its protein accumulates through autophosphorylation and redox-mediated regulation. OsVIRK1 physically interacts with the RSV coat protein (CP), a known immune elicitor, and nonstructural protein 3 (NS3), an antiviral RNA-silencing suppressor, at the TGN/EE. OsVIRK1 is required for CP-triggered defense gene expression. It phosphorylates NS3, reducing NS3 accumulation in the cytoplasm and thus repressing its activity as an RNA-silencing suppressor. Our findings suggest that OsVIRK1 recognizes viral proteins at the TGN/EE to inhibit infection by activating plant antiviral immunity and dampening viral counterdefense.

DNA unwinding and primer synthesis are fundamental processes in genome replication. The human herpes simplex virus type 1 (HSV-1) helicase-primase forms a unique heterotrimeric primosome that is essential for viral DNA unwinding and primer synthesis and represents an ideal drug target. However, its molecular mechanism remains poorly understood. Here we report the cryo-electron microscopic structure of the primosome in complex with single-stranded DNA, ADP and Mg²⁺ to 3.47 Å resolution, which reveals that the primosome forms an unprecedented architecture in a fully open DNA binding groove between the helicase domains 1A and 2A-2B and that the primase subunit UL52 interacts extensively with the helicase subunit UL5 and accessory protein subunit UL8. Integrating mutagenesis, biochemical assays, structural analysis and 3D variability display analysis, we have identified the active sites of the ATPase, helicase and primase and critical interfaces between UL52, UL5 and UL8. Our work suggests that the primosome unwinds and translocates DNA via bidirectional rotation, and proposes a mechanistic model for DNA-dependent ATPase activation and alternating activity between helicase and primase. Herpesviridae family viruses pose significant threats to human health worldwide, and this trimeric assembly of primosomes is conserved. Our work provides a framework for understanding replication mechanisms across related viruses and for the rational design of broad-spectrum antivirals.

In cancer, extrachromosomal DNA (ecDNA) contributes to tumor heterogeneity and is associated with poor prognosis, but studies on patient-derived ecDNA are relatively limited at single-cell resolution. Here, we introduce scCirclehunter, a framework designed to identify ecDNA from scATAC-seq data and assign ecDNA to specific cell populations. Leveraging scCirclehunter and available glioblastoma (GBM) datasets, we uncover the inter-cellular heterogeneity of ecDNA-carrying cells across GBM patients and trace the trajectories of malignant cells within a single patient that harbors multiple ecDNAs. By integrating scRNA-seq data, we use ecNR2E1 as an example to demonstrate that ecDNA drives tumor progression in GBM through several mechanisms. Additionally, our findings suggest a potential link between ecDNA and increased mitochondrial transfer frequency. Overall, scCirclehunter provides a novel framework for analyzing patient-specific ecDNAs with single-cell precision, offering insights into the role of ecDNA-carrying cells in driving GBM heterogeneity.

Protease-activated receptor 2 (PAR2) is a transmembrane receptor that is irreversibly activated by proteolytic cleavage of its N-terminus via extracellular proteases, resulting in the release of the tethered ligand (TL), which binds to and activates the receptor. PAR2 plays a pivotal role in the inflammatory response and pain sensation and is a promising drug target for treating arthritis, asthma, and neuronal pain. Here, we present the cryo-electron microscopy structures of active PAR2 complexed with miniG_s/q and miniG₁₃. Combining functional assays with structural analysis, our study revealed that TL forms a parallel β-sheet with the extracellular loop 2 of PAR2 to engage the receptor. The binding of TL triggers a conformational rearrangement in the transmembrane core, releasing the inhibitory ion lock and allowing receptor activation. Furthermore, we provide structural insights into the engagement of G_q and G₁₃ with PAR2, highlighting that a hydrophobic interaction mediated by the last methionine residue of Gα₁₃ is crucial for G₁₃ coupling selectivity. In combination with molecular dynamics simulations and mutagenesis, we identified the I39^TL3/D62^N-term interaction at the pocket side of the receptor as a key determinant of G₁₃ signaling. Disrupting this interaction significantly inhibits G₁₃ signaling while preserving G_q activity, enabling us to design a biased peptide ligand that selectively activates G_q signaling. The information revealed in this study provides a framework for understanding PAR2 signaling and offers a rational basis for the design of biased PAR2 ligands.

Myopia is a leading cause of visual impairment, with its prevalence rising rapidly worldwide. Our prior investigations suggest that cross-organ communication, involving the eye, brain, and gut, may play a role in myopia. However, the extent of this cross-organ communication in myopia remains unclear. To elucidate the underlying mechanisms, this study generates a comprehensive pan-tissue transcriptome profile of myopic mice covering eye, brain, blood, bone marrow, spleen, thymus, intestines, liver, kidney, lung, and adrenal gland using single-cell RNA sequencing (scRNA-seq). Widespread immunologic alterations in myopia are identified, characterized by a significant increase in macrophage abundance and macrophage-mediated cell communications across multiple tissues. Notably, these macrophages exhibit a cross-tissue proinflammatory phenotype, which is marked by significant activation of the hypoxia pathway, with upregulation of key markers, including Car1, HIF-1α, and reactive oxygen species, a pattern also observed in the blood of myopic patients. Further analysis suggested that hypoxia stress likely regulates the energy metabolism of proinflammatory macrophages. Inhibition of the hypoxia pathway suppressed the proinflammatory phenotype of macrophages and their hypoxia-related gene expression in myopic mice, reducing the degree of myopia. More importantly, analysis of a large cohort of 114,661 patients reveals 16 extraocular diseases with a myopia-biased prevalence. Our findings underscore the link between myopia and extraocular diseases and suggest that proinflammatory macrophages may potentially serve as the shared mechanism across organs.

Immunochemotherapy has shown promising outcomes in treating small-cell lung cancer. To explore whether surgery after immunochemotherapy benefits patients with stage I‒III small-cell lung cancer, we conducted a phase II trial (NCT04539977). Eligible patients received four cycles of anti-PD-L1 antibody (TQB2450) therapy and chemotherapy, followed by surgery or radiotherapy and one-year maintenance immunotherapy (TQB2450). Forty patients were enrolled between December 2020 and January 2023. Thirty-eight (95.0%) patients had stage III disease. We found that the objective response rate, as the primary endpoint of this study, was 92.5% (95% CI: 83.9%‒100%) in the intention-to-treat population. At a median follow-up of 25.8 months, the median event-free survival (EFS) was 16.2 months. The median overall survival (OS) was not reached. The major pathological response and pathological complete response rate of operative patients (n = 21) were 61.9% and 42.9%, respectively. The 24-month EFS and 24-month OS of operative patients were 61.9% and 85.7%, respectively. All patients with N1 disease (n = 9) underwent surgery, with the 24-month EFS of 66.7% and 24-month OS of 88.9%. The most common TQB2450-specific adverse event was rash of grade 1‒2 (12.5%). We further explored the biomarker of immunochemotherapy and molecular changes during immunochemotherapy through bulk-RNA sequencing and whole-exome sequencing. We demonstrated that PRSS8 was a potential biomarker for poor effectiveness of immunochemotherapy. In conclusion, surgery after neoadjuvant immunochemotherapy is feasible for treating patients with stage I‒III small-cell lung cancer.