技术资料

Ceramides are bioactive sphingolipids that have physiological effects on inflammation,apoptosis,and mitochondrial dysfunction. They may play a critical role in the harm of ischemia/reperfusion (IR). Ceramides and IR injury are not well-studied,and there is a lack of human data. Current studies aimed to investigate the role of ceramide buildup in cardiomyocytes (CMs) death using CMs derived from human induced pluripotent stem cell (hiPSC) as a model for simulating IR injury in vitro. In our model,serum- and glucose-free media was used to expose hiPSC-derived CMs to hypoxia (3% O 2 ) for 6 h (hrs),followed by reoxygenation (20% O 2 ) for 16 h. In contrast to normoxia (control) or hypoxia (ischemia),our data showed that following IR,there was an increase in the formation of mitochondrial superoxide and the mRNA levels of genes regulating ceramide synthesis,such as CerS2 and CerS4 in CMs. Further,there was a considerable rise in the levels of total ceramide,long-chain (C16:0,C18:0,and C18:1),and very long-chain (C22:0 and C24:1) ceramide species in CMs following reperfusion in comparison to control or ischemic CMs. Interestingly,compared to CMs exposed to IR without inhibitor,our data showed that inhibition of ceramide formation with fumonisin B1 (FB1) significantly lowered ceramide levels,reduced apoptosis,improved mitochondrial function,and enhanced survival of CMs exposed to IR. Furthermore,we used a transgenic mouse model,in which the CerS2 gene was overexpressed in the CMs of α-MHC-CerS2 mice,to validate the basic idea that ceramide contributes to heart disease in vivo. Our results showed that the heart tissues of α-MHC-CerS2 mice had significant levels of long-chain and very long-chain ceramides,which causes increased apoptosis,proinflammatory cytokines,interstitial inflammatory cell infiltration,and collagen deposition. Results from both in vitro and in vivo experiments show that ceramides have a significant role in either mediating or inducing damage to CMs. Additionally,in vitro findings show that ceramide reduction improves the outcome of IR injury by lowering intracellular Ca 2+ [Ca 2+ ] i concentration and improves mitochondrial function changes during IR. The online version contains supplementary material available at 10.1186/s13287-025-04340-3. View Publication

Adeno-associated viral (AAV) vector-based gene therapy is gaining foothold as treatment for genetic neurological diseases with encouraging clinical results. Nonetheless,dose-dependent adverse events have emerged in recent clinical trials through mechanisms that remain unclear. We have modelled here the impact of AAV transduction in cell models of the human central nervous system (CNS),taking advantage of induced pluripotent stem cells. Our work uncovers vector-induced innate immune mechanisms that contribute to cell death. While empty AAV capsids were well tolerated,the AAV genome triggered p53-dependent DNA damage responses across CNS cell types followed by the induction of inflammatory responses. In addition,transgene expression led to MAVS-dependent activation of type I interferon responses. Formation of DNA damage foci in neurons and gliosis were confirmed in murine striatum upon intraparenchymal AAV injection. Transduction-induced cell death and gliosis could be prevented by inhibiting p53 or by acting downstream on STING- or IL-1R-mediated responses. Together,our work identifies innate immune mechanisms of vector sensing in the CNS that can potentially contribute to AAV-associated neurotoxicity. Subject terms: Neuroimmunology,Innate immunity,Neural stem cells View Publication

This study aimed to assess the efficacy of Quality and Quantity media-cultured mononuclear cells (QQ-MNCs) for promoting nerve regeneration in a mouse sciatic nerve transection model. Human peripheral blood mononuclear cells (PB-MNCs) and QQ-MNCs derived from healthy volunteers were used/compared. The left sciatic nerve was surgically transected in 27 mice. After complete nerve transection was confirmed,end-to-end direct epineurial nerve repair was performed using 9–0 nylon. Fibrin glue was applied to the tissue around the injury site to limit diffusion of the study treatment followed by application of 0.5 ml phosphate buffered saline (PBS) or PB-MNCs (2x10 6 cells) or QQ-MNCs (2x10 6 cells) to the injury site. The skin was then closed using 6–0 nylon. Histomorphology,immunohistochemistry,electrophysiologic examination,and functional assessment were evaluated at 12-weeks followed by euthanasia and subsequent harvesting of the left sciatic nerves and the left and right gastrocnemius muscles for examination. QQ-MNCs mice exhibited significant improvement in all histomorphologic parameters (axon fiber diameter,myelin thickness,percentage of nerve density) and immunohistochemistry assays (S100,SOX10,GFAP,neurofilament,IL-1β,VEGF,anti-HNA,TNF-α,vWF) compared to PBS mice (all p < 0.05). QQ-MNCs mice also had a significantly higher Basso Mouse Scale score compared to PBS mice ( p = 0.018). The percentage of nerve density adjacent to the injury site was significantly higher in QQ-MNCs mice than in PB-MNCs mice ( p = 0.049). IL-1β expression was significantly lower in QQ-MNCs mice than in PB-MNCs mice ( p = 0.01). QQ-MNCs mice demonstrated significantly better functional and histomorphologic outcomes of nerve regeneration compared to PB-MNCs mice and PBS mice. View Publication

The CEBPA transcription factor is frequently mutated in acute myeloid leukemia (AML). Mutations in the CEBPA gene,which are typically biallelic,result in the production of a shorter isoform known as p30. Both the canonical 42-kDa isoform (p42) and the AML-associated p30 isoform bind chromatin and activate transcription,but the specific transcriptional programs controlled by each protein and how they are linked to a selective advantage in AML is not well understood. Here,we show that cells expressing the AML-associated p30 have reduced baseline inflammatory gene expression and display altered dynamics of transcriptional induction in response to LPS,consequently impacting cytokine secretion. This confers p30-expressing cells an increased resistance to the adverse effects of prolonged exposure to inflammatory signals. Mechanistically,we show that these differences primarily arise from the differential regulation of AP-1 family proteins. In addition,we find that the impaired function of the AP-1 member ATF4 in p30-expressing cells alters their response to ER stress. Collectively,these findings uncover a link between mutant CEBPA,inflammation and the stress response,potentially revealing a vulnerability in AML. Subject terms: Gene regulation,Acute myeloid leukaemia,Transcriptional regulatory elements,Epigenetics in immune cells View Publication

Osteoporosis diagnoses are increasing in the ageing population,and although some treatments exist,these have several disadvantages,highlighting the need to identify new drug targets. G protein-coupled receptors (GPCRs) are transmembrane proteins whose surface expression and extracellular activation make them desirable drug targets. Our previous studies have identified 144 GPCR genes to be expressed in primary human osteoclasts,which could provide novel drug targets. The development of high-throughput assays to assess osteoclast activity would improve the efficiency at which we could assess the effect of GPCR activation on human bone cells and could be utilised for future compound screening. Here,we assessed the utility of a high-content imaging (HCI) assay that measured cytoplasmic-to-nuclear translocation of the nuclear factor of activated T cells-1 (NFATc1),a transcription factor that is essential for osteoclast differentiation,and resorptive activity. We first demonstrated that the HCI assay detected changes in NFATc1 nuclear translocation in human primary osteoclasts using GIPR as a positive control,and then developed an automated analysis platform to assess NFATc1 in nuclei in an efficient and unbiased manner. We assessed six GPCRs simultaneously and identified four receptors (FFAR2,FFAR4,FPR1 and GPR35) that reduced osteoclast activity. Bone resorption assays and measurements of TRAP activity verified that activation of these GPCRs reduced osteoclast activity,and that receptor-specific antagonists prevented these effects. These studies demonstrate that HCI of NFATc1 can accurately assess osteoclast activity in human cells,reducing observer bias and increasing efficiency of target detection for future osteoclast-targeted osteoporosis therapies. View Publication

Lipid dyshomeostasis and tau pathology are present in frontotemporal lobar degeneration (FTLD) and Alzheimer’s disease (AD). However,the relationship between lipid dyshomeostasis and tau pathology remains unclear. We report that GRAM Domain Containing 1B (GRAMD1B),a nonvesicular cholesterol transporter,is increased in excitatory neurons of human neural organoids (HNOs) with the MAPT R406W mutation. Human FTLD,AD cases,and PS19 tau mice also have increased GRAMD1B expression. We show that overexpression of GRAMD1B increases levels of free cholesterol,lipid droplets,and impairs autophagy flux. Modulating GRAMD1B in iPSC-derived neurons also alters key autophagy-related components such as PI3K,phospho-AKT,and p62,as well as phosphorylated tau,and CDK5R1. Blocking GRAMD1B function decreases free cholesterol and lipid droplets. Knocking down GRAMD1B additionally reduces phosphorylated tau,and CDK5R1 expression. Our findings elucidate the role of GRAMD1B in the nervous system and highlight its relevance to FTLD and AD. Subject terms: Diseases of the nervous system,Ageing View Publication

Trogocytosis is the process by which a recipient cell siphons small membrane fragments and proteins from a donor cell and can be utilized by cancer cells to avoid immune detection. We observed lymphocyte specific protein expressed by triple negative breast cancer (TNBC) cells via immunofluorescence imaging of patient samples. Image analysis of Cluster of Differentiation 45RA (CD45RA) expression,a naïve T cell specific protein,revealed that all stages of TNBCs express CD45RA. Flow cytometry revealed TNBC cells trogocytose CD45 protein from T cells. We also showed that the acquisition of these lymphoid markers is contact dependent. Confocal and super-resolution imaging further revealed CD45+ spherical structures containing T cell genomic DNA inside TNBC cells after co-culture. Trogocytosis between T cells and TNBC cells altered tumor cell expression of PTPRC,the gene that encodes for CD45. Our results revealed that CD45 is obtained by TNBC cells from T cells via trogocytosis and that TNBC cells express CD45 intracellularly and on the membrane. View Publication

Suppression of anticancer immune function is a key driver of tumorigenesis. Identifying molecular pathways that inhibit anticancer immunity is critical for developing novel immunotherapeutics. One such molecule that has recently been identified is the carbohydrate polysialic acid (polySia),whose expression is dramatically upregulated on both cancer cells and immune cells in breast cancer patient tissues. The role of polySia in the anticancer immune response,however,remains incompletely understood. In this study,we profile polySia expression on both healthy primary immune cells and on infiltrating immune cells in the tumour microenvironment (TME). These studies reveal polySia expression on multiple immune cell subsets in patient breast tumors. We find that stimulation of primary T-cells and macrophages in vitro induces a significant upregulation of polySia expression. We subsequently show that polySia is appended to a range of different carrier proteins within these immune cells. Finally,we find that selective removal of polySia can significantly potentiate killing of breast cancer cells by innate immune cells. These studies implicate polySia as a significant negative regulator of anticancer immunity. View Publication

To produce pluripotent stem cells from peripheral blood mononuclear cells (PBMCs) of a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and culture and differentiate them into vascular organoids,producing a disease model for cerebral small vessel disease (CSVD). (1) PMBCs from patients clinically diagnosed with CADASIL ( NOTCH3 p.R141C) were induced to differentiate into pluripotent stem cells (iPSCs); the quality and differentiation ability of the iPSCs were determined. (2) CADASIL-derived iPSCs and control iPSCs were cultured and differentiated into vascular organoids. The differences in the morphological structure of the two differentiated groups of vascular organoids were observed,and both were identified. (1) No mycoplasma infections were detected in the iPSCs prepared from the PBMCs of patients with CADASIL. The short tandem repeat (STR) identification verified that the iPSCs originated from the patient,and the karyotype was normal. Flow cytometry and immunofluorescence detection revealed that the iPSCs expressed SSEA4,OCT4,and NANOG stem proteins. Tri-germ differentiation testing confirmed that the iPSCs expressed the endoderm markers SOX17 and FOXA2,the mesoderm markers Brachyury and α-SMA,and the ectoderm markers Pax6 and β-III Tubulin. (2) CADASIL-derived iPSCs and control iPSCs were induced to differentiate and produce endothelial networks and vascular networks,ultimately forming vascular organoids. Compared with control vascular organoids,CADASIL vascular organoids exhibited lower growth density,earlier blood vessel sprouting,longer and thinner vascular filaments,and smaller final vascular organoids. The vascular organoids from the two sources expressed the endothelial cell marker CD31,the vascular smooth muscle marker α-SMA,and the pericyte marker PDGFR-β. Reprogramming technology can be used to induce PBMCs to become iPSCs,and a CSVD disease model can be successfully constructed by culturing and differentiating the iPSCs into CADASIL vascular organoids. The NOTCH3 p.R141C mutation suppresses the vascular differentiation process in CADASIL. View Publication

The search for an effective cell replacement therapy for diabetes has driven the development of “perfect” pancreatic islets from human pluripotent stem cells (hPSCs). These hPSC-derived pancreatic islet-like β cells can overcome the limitations for disease modelling,drug development and transplantation therapies in diabetes. Nevertheless,challenges remain in generating fully functional and mature β cells from hPSCs. This review underscores the significant efforts made by researchers to optimize various differentiation protocols aimed at enhancing the efficiency and quality of hPSC-derived pancreatic islets and proposes methods for their improvement. By emulating the natural developmental processes of pancreatic embryogenesis,specific growth factors,signaling molecules and culture conditions are employed to guide hPSCs towards the formation of mature β cells capable of secreting insulin in response to glucose. However,the efficiency of these protocols varies greatly among different human embryonic stem cell (hESC) and induced pluripotent stem cell (hiPSC) lines. This variability poses a particular challenge for generating patient-specific β cells. Despite recent advancements,the ultimate goal remains to develop a highly efficient directed differentiation protocol that is applicable across all genetic backgrounds of hPSCs. Although progress has been made,further research is required to optimize the protocols and characterization methods that could ensure the safety and efficacy of hPSC-derived pancreatic islets before they can be utilized in clinical settings. View Publication

Allogeneic transplantation of CCR5 null hematopoietic stem and progenitor cells (HSPCs) is the only known cure for HIV-1 infection. However,this treatment is limited because of the rarity of CCR5 -null matched donors,the morbidities associated with allogeneic transplantation,and the prevalence of HIV-1 strains resistant to CCR5 knockout (KO) alone. Here,we propose a one-time therapy through autologous transplantation of HSPCs genetically engineered ex vivo to produce both CCR5 KO cells and long-term secretion of potent HIV-1 inhibiting antibodies from B cell progeny. CRISPR-Cas9-engineered HSPCs engraft and reconstitute multiple hematopoietic lineages in vivo and can be engineered to express multiple antibodies simultaneously (in pre-clinical models). Human B cells engineered to express each antibody secrete neutralizing concentrations capable of inhibiting HIV-1 pseudovirus infection in vitro. This work lays the foundation for a potential one-time functional cure for HIV-1 through combining the long-term delivery of therapeutic antibodies against HIV-1 and the known efficacy of CCR5 KO HSPC transplantation. Subject terms: Stem-cell biotechnology,Haematopoietic stem cells,CRISPR-Cas9 genome editing View Publication

Motor axon regeneration following peripheral nerve injury is critical for motor recovery but therapeutic interventions enhancing this are not available. We conduct a phenotypic screen on human motor neurons and identified blebbistatin,a non-muscle myosin II inhibitor,as the most effective neurite outgrowth promotor. Despite its efficacy in vitro,its poor bioavailability limits in vivo application. We,therefore,utilize a blebbistatin analog,NMIIi2,to explore its therapeutic potential for promoting axon regeneration. Local NMIIi2 application directly to injured axons enhances regeneration in human motor neurons. Furthermore,following a sciatic nerve crush injury in male mice,local NMIIi2 administration to the axonal injury site facilitates motor neuron regeneration,muscle reinnervation,and functional recovery. NMIIi2 also promotes axon regeneration in sensory,cortical,and retinal ganglion neurons. These findings highlight the therapeutic potential of topical NMII inhibition for treating axon damage. Subject terms: Regeneration and repair in the nervous system,Movement disorders View Publication