参考文献

The nucleocapsid N is one of four structural proteins of the coronaviruses. Its essential role in genome encapsidation makes it a critical therapeutic target for COVID-19 and related diseases. However,the inherent disorder of full-length N hampers its structural analysis. Here,we describe a stepwise method using viral-derived RNAs to stabilize SARS-CoV-2 N for EM analysis. We identify pieces of RNA from the SARS-CoV-2 genome that promote the formation of structurally homogeneous N dimers,intermediates of assembly,and filamentous capsid-like structures. Building on these results,we engineer a symmetric RNA to stabilize N protein dimers,the building block of high-order assemblies,for EM studies. We combine domain-specific monoclonal antibodies against N with chemical cross-linking mass spectrometry to validate the spatial arrangement of the N domains within the dimer. Additionally,our cryo-EM analysis reveals novel antigenic sites on the N protein. Our findings provide insights into N protein´s architectural and antigenic principles,which can guide design of pan-coronavirus therapeutics. The authors stabilize the SARS-CoV-2 nucleocapsid (N) dimer assembly using a short RNA and chemical crosslinker for EM analysis,revealing its domain arrangement and antigenic sites to advance understanding and guide pan-coronavirus therapeutic design. View Publication

Anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis (DM) is often complicated by rapidly progressive interstitial lung disease (RP-ILD),leading to early mortality. Previous studies on the pathogenesis of anti-MDA5-positive DM highlighted type I interferons (IFNs),while recent investigations reported the significance of a type III IFN,IFN-λ3. We investigated a range of cytokines,including type I/II/III IFNs,in serum samples from anti-MDA5-positive DM patients collected at diagnosis before treatment introduction. Elevations of IFN-β and λ3 were identified as the hallmark of anti-MDA5-positive DM,in comparison with other myositis subtypes,systemic lupus erythematosus,and COVID-19 pneumonia. The elevation of IFN-λ3 was associated with decreased CD56dimCD16pos NK cells in circulation. The unique cytokine profile with type I/III IFN upregulation in anti-MDA5-positive DM was replicated in independent validation cohorts. A cluster analysis using serum type I/III IFN levels identified three subgroups in anti-MDA5-positive DM: mild elevations of IFN-α/β and λ3; a marked increase in IFN-λ3 alone; and pronounced elevations of IFN-α/β with mild to moderate increase in IFN-λ3. Patients in the cluster with a marked elevation of IFN-λ3 alone tended to present with RP-ILD and decreased survival. The combination of serum type I/III IFN levels could serve as a prognostic biomarker in anti-MDA5-positive DM. View Publication

Aging is associated with immune dysfunction,but long-term endurance training may confer protective effects on immune cell function. This study investigates how natural killer (NK) cell phenotypes,functional markers,and metabolism differ between endurance-trained and untrained older adults. Ex vivo expanded NK cells from endurance-trained (63.6 ± 2.1 years) and untrained (64.3 ± 3.3 years) males were exposed to adrenergic blockade (propranolol; 0–200 ng/mL) or mTOR inhibition (rapamycin; 10–100 ng/mL),both with or without PMA-induced inflammatory stimulation. Flow cytometry assessed NK subsets,activation (CD38,CD57,CD107a,NKG2D),senescence (KLRG1),and inhibitory markers (PD-1,LAG-3,TIM-3,NKG2A). Seahorse analysis measured metabolic parameters. Trained participants displayed healthier immune profiles (lower NLR,SII) and higher effector NK cells with lower cytotoxic subsets. Propranolol at 100 ng/mL blunted PMA-driven increases in CD57,CD107a,and NKG2D,while potentiating regulatory markers KLRG1,LAG-3,and PD-1 in the trained group,indicating stronger immunoregulation. With rapamycin,trained NK cells preserved NKG2D and CD107a at 10 ng/mL,maintaining cytotoxicity and degranulation. In contrast,at 100 ng/mL rapamycin plus PMA,trained NK cells shifted toward an effector phenotype with higher CD57 and CD107a,yet a blunted PMA-increased LAG-3 and TIM-3,suggesting resistance to exhaustion. PD-1 and KLRG1 remained elevated,reflecting balanced immune control. Mitochondrial analysis revealed that trained NK cells exhibited higher basal and maximal OCR,greater spare respiratory capacity,and OCR/ECAR ratio,reflecting superior metabolic fitness. These findings indicate that endurance-trained older adults have NK cells with greater functional adaptability,reduced senescence,and enhanced metabolism under inflammatory and pharmacological stress.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-06057-y. View Publication

ObjectiveBifidobacterium is known to be depleted in patients with atopic dermatitis (AD). This study aims to investigate the potential prophylactic effects of Bifidobacterium animalis subsp. lactis BX-BC08 (B. lactis BX-BC08) in a murine model of AD.DesignThe immunosuppressive and anti-inflammatory effects of BX-BC08 were evaluated in a MC903-induced AD mouse model. Gut microbiota composition was analyzed by metagenomic sequencing,while high-performance liquid chromatography-mass spectrometry (HPLC-MS) was employed to identify anti-inflammatory molecules produced by B. lactis BX-BC08.ResultsBX-BC08 significantly attenuated pro-inflammatory responses,scaling and swelling in the MC903-induced AD like murine model compared to controls. Fecal microbial profiling revealed an enrichment of probiotics and a reduction of pro-inflammatory bacteria in BX-BC08 treated mice. Metabolic analysis of BX-BC08 bacteria culture supernatant and treated mice identified a significant enrichment of alpha-Ketoglutaric acid (AKG). Functional validation in the murine AD model demonstrated that AKG strongly suppressed T helper 2 (Th2)-driven pro-inflammatory responses.ConclusionBX-BC08 mitigates AD-like inflammation by producing the anti-inflammatory metabolite AKG. BX-BC08 could serve as a novel prophylactic agent for AD prevention.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12967-025-06769-9. View Publication

The long-term maintenance of hematopoietic stem cells (HSCs) relies on the regulation of endoplasmic reticulum (ER) stress at a low level,but the underlying mechanism remains poorly understood. Here,we demonstrate that suppression of ER stress improves the functions of HSCs and protects HSCs against ionizing radiation (IR)-induced injury. We identify epithelial membrane protein 1 (EMP1) as a key regulator that mitigates ER stress in HSCs. Emp1 deficiency leads to the accumulation of protein aggregates and elevated ER stress,ultimately resulting in impaired HSC maintenance and self-renewal. Mechanistically,EMP1 is located within the ER and interacts with ceramide synthase 2 (CERS2) to limit the production of a class of sphingolipids,dihydroceramides (dhCers). DhCers accumulate in Emp1-deficient HSCs and induce protein aggregation. Furthermore,Emp1 deficiency renders HSCs more susceptible to IR,while overexpression of Emp1 or inhibition of CERS2 protects HSCs against IR-induced injury. These findings highlight the critical role played by the EMP1-CERS2-dhCers axis in constraining ER stress and preserving HSC potential. A new study shows EMP1 protects hematopoietic stem cells by suppressing sphingolipid metabolism and ER stress. EMP1 interacts with CERS2 to limit dihydroceramide production,which causes protein aggregation when elevated. View Publication

IntroductionCD8+ T cells are vital in the immune control of cancer and a key player in cell-based cancer immunotherapy. Recent studies have shown that microbial short-chain fatty acids (SCFA) can promote both effector and memory phenotypes in CD8+ T cells and may thereby enhance protection against cancer.MethodsIn this study,we determined the effect of SCFA butyrate on mouse CD8+ T cell function in vitro and in vivo,using the OT-I model.ResultsButyrate co-culture with anti-CD3 + anti-CD28 activated T cells in vitro enhanced the frequency of effector CD8+ IFN-γ-producing cells,and the amount of cytokine produced per cell. Culture with butyrate also enhanced the activation,TCR expression,and levels of phosphorylated mTOR proteins within CD8+ T cells but reduced proliferation rate and increased apoptosis. Butyrate-treated activated cells conferred tumor protection after adoptive transfer. Butyrate-treated cells were present at higher frequencies within the tumor compared to non-butyrate treated cells,and expressed IFN-γ. When analyzed using high dimensional cytometry,the tumors of mice that received butyrate-treated cells were enriched in clusters displaying an effector memory phenotype with high expression of IL-15Rβ and T-bet.DiscussionOur findings show that butyrate promotes the effector activity of CD8+ T cells in culture,which can persist in vivo while also stimulating memory phenotypes. Consequently,butyrate treatment may have strong application in T cell-based immunotherapies to improve protective cell functions and patient outcomes. View Publication

Neutrophils are highly abundant in the oral mucosal tissues,and their balanced activation and clearance are essential for immune homeostasis. Here,we demonstrate that neutrophils infected with the bacterial pathogen Porphyromonas gingivalis (Pg) are captured alive by macrophages in a manner that bypasses all known receptor-ligand interactions involved in the phagocytosis of either live or dead cells. Mechanistically,upon interaction with Pg,or its protease RgpB (gingipains),live neutrophils undergo rapid remodeling of their proteomes,generating neoepitopes. N-terminomics-based proteomic profiling identified multiple RgpB cleavage sites on several azurophilic granule proteins that are translocated to the surface of live neutrophils via low-level degranulation and activate macrophage αMβ2 integrin receptors,thus mediating internalization of non-apoptotic neutrophils within macrophage phagosomes. Macrophages with entrapped live neutrophils exhibit phenotypic and transcriptional reprogramming,consistent with inflammatory outcomes in vitro and in vivo. In contrast to the immunosuppressive outcomes associated with efferocytosis of apoptotic neutrophils,live neutrophil entrapment failed to fully activate several catabolic and metabolic processes and exhibited a defective activation of PPAR-γ mediated pro-resolution pathways,thereby promoting bacterial persistence and hindering the resolution of inflammation. Thus,our data demonstrate a novel immune subversion strategy unique to Pg and reveal a previously unknown mode of live neutrophil sequestration into macrophages during an infection. View Publication

The human bone marrow (BM) microenvironment involves hematopoietic and non-hematopoietic cell subsets organized in a complex architecture. Tremendous efforts have been made to model it in order to analyze normal or pathological hematopoiesis and its stromal counterpart. Herein,we report an original,fully-human in vitro 3D model of the BM microenvironment dedicated to study interactions taking place between mesenchymal stromal cells (MSC) and hematopoietic stem and progenitor cells (HSPC) during the hematopoietic differentiation. This fully-human Artificial Marrow Organoid (AMO) model is highly efficient to recapitulate MSC support to myeloid differentiation and NK cell development from the immature CD34 + HSPCs to the most terminally differentiated CD15 + polymorphonuclear neutrophils,CD64 + monocytes or NKG2A-KIR2D + CD57 + NK subset. Lastly,our model is suitable for evaluating anti-leukemic NK cell function in presence of therapeutic agents. Overall,the AMO is a versatile,low cost and simple model able to recapitulate normal hematopoiesis and allowing more physiological drug testing by taking into account both immune and non-immune BM microenvironment interactions.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-07717-9. View Publication

Myelodysplastic syndrome disease (MDS) is caused by the successive acquisition of mutations and thus displays a variable risk for progression to AML. Mutations in CEBPA are commonly associated with a high risk of disease progression,but whether they are causative for AML development is unclear. To analyse the molecular basis of disease progression we generated MDS patient-derived induced pluripotent stem cells from a low risk male patient harbouring RUNX1/SRSF2 mutations. This experimental model faithfully recapitulates the patient disease phenotypes upon hematopoietic differentiation. Introduction of a frameshift mutation affecting the C/EBPα bZIP domain in cells from low-risk stages mimicks disease progression by reducing clonogenicity of myeloid cells,blocking granulopoiesis and increasing erythroid progenitor self-renewal capacity. The acquisition of this mutation reshapes the chromatin landscape at distal cis-regulatory regions and promotes changes in cellular composition as observed by single cell RNAseq. Mutant C/EBPα is therefore causative for MDS disease progression. Our work identifies mutant CEBPA as causative for MDS disease progression,providing a new isogenic MDS experimental model for drug screening to improve diagnostic and therapeutic strategies. In Myeloiddysplastic syndromes,CEBPA mutations are linked to disease progression and AML. Here,the authors use somatic reprogramming and genome editing to generate isogenic cell lines from an MDS patient,identifying CEBPA bZIP domain disruption as causative for disease progression. View Publication

DEAD-box helicase 41 (DDX41) is implicated in germline (GL)-predisposed myeloid neoplasms,where pathogenic GL variants often lead to disease following the acquisition of a somatic variant in trans,most commonly p.R525H. However,the precise molecular mechanisms by which DDX41 variants contribute to the pathogenesis of myeloid neoplasms remain poorly understood,partly due to challenges in establishing cellular and animal models that faithfully recapitulate the human disease phenotype. This limitation highlights the necessity of directly analyzing primary human disease cells. In this case report,conducted to pursue this objective,we implemented single-cell RNA sequencing integrated with genotyping at the p.R525 locus in a myelodysplastic neoplasm (MDS) harboring both germline and somatic DDX41 variants,leveraging highly efficient Terminator-Assisted Solid-phase cDNA amplification and sequencing. We found that acquiring p.R525H induced G2/M cell cycle arrest selectively in colony-forming unit-erythroid cells,accompanied by R-loop accumulation,which impaired erythropoiesis through DNA damage. In hematopoietic stem and myeloid progenitor populations,gene expression profiles were largely similar between p.R525H-positive and -negative cells. However,ligand-receptor interaction and transcriptional regulation analyses suggested a non-cell-autonomous influence from p.R525H-expressing cells on GL variant-only cells. This interaction drove convergence toward a shared expression profile,highlighting an intricate interplay shaping the patient’s MDS phenotype. View Publication