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Although a number of growth factors have been shown to be involved in neurogenesis,the role of inflammatory cytokines remains relatively unexplored in the normal brain. Here we investigated the effect of interferon gamma (IFNgamma) in the regulation of neural precursor (NP) activity in both the developing and the adult mouse brain. Exogenous IFNgamma inhibited neurosphere formation from the wild-type neonatal and adult subventricular zone (SVZ). More importantly,however,these effects were mirrored in vivo,with mutant mice lacking endogenous IFNgamma displaying enhanced neurogenesis,as demonstrated by an increase in proliferative bromodeoxyuridine-labeled cells in the SVZ and an increased percentage of newborn neurons in the olfactory bulb. Furthermore,NPs isolated from IFNgamma null mice exhibited an increase in self-renewal ability and in the capacity to produce differentiated neurons and oligodendrocytes. These effects resulted from the direct action of IFNgamma on the NPs,as determined by single-cell assays and the fact that nearly all the neurospheres were derived from cells positive for major histocompatibility complex class I antigen,a downstream marker of IFNgamma-mediated activation. Moreover,the inhibitory effect was ameliorated in the presence of SVZ-derived microglia,with their removal resulting in almost complete inhibition of NP proliferation. Interestingly,in contrast to the results obtained in the adult,exogenous IFNgamma treatment stimulated neurosphere formation from the embryonic brain,an effect that was mediated by sonic hedgehog. Together these findings provide the first direct evidence that IFNgamma acts as a regulator of the active NP pool in the non-inflammatory brain. View Publication

Hantaviruses are zoonotically transmitted from rodents to humans through the respiratory route,with no currently approved antivirals or widely available vaccines. The recent discovery of interhuman-transmitted Andes virus (ANDV) necessitates the systematic identification of cell tropism,infective potential,and potent therapeutic agents. We utilized human primary lung endothelial cells,various pluripotent stem cell-derived heart and brain cell types,and established human lung organoid models to evaluate the tropisms of Old World Hantaan (HTNV) and New World ANDV and Sin Nombre (SNV) viruses. ANDV exhibited broad tropism for all cell types assessed. SNV readily infected pulmonary endothelial cells,while HTNV robustly amplified in endothelial cells,cardiomyocytes,and astrocytes. We also provide the first evidence of hantaviral infection in human 3D distal lung organoids,which effectively modeled these differential tropisms. ANDV infection transcriptionally promoted cell injury and inflammatory responses,and downregulated lipid metabolic pathways in lung epithelial cells. Evaluation of selected drug candidates and pharmacotranscriptomics revealed that the host-directed small molecule compound urolithin B inhibited ANDV infection and restored cellular metabolism with minimal changes in host transcription. Given the scarcity of academic BSL-4 facilities that enable in vivo hantaviral studies,this investigation presents advanced human cell-based model systems that closely recapitulate host cell tropism and responses to infection,thereby providing critical platforms to evaluate potential antiviral drug candidates. Author summaryHantaviruses are fatal human pathogens that cause hemorrhagic fevers and are classified into either Old World or New World groups. Though most hantaviruses utilize zoonotic transmission,the New World Andes virus (ANDV) is unique in its ability to spread between humans. This distinct transmission mode underscores the need to investigate its cell tropism,pathogenicity,and therapeutic targets. Thus,we performed a systems-level comparison of the Old World Hantaan virus (HTNV) and New World hantaviruses,ANDV and Sin Nombre virus (SNV),using human lung,heart,and brain cell models,alongside lipidomic and transcriptomic profiling. We observed that ANDV exhibits broad tropism,infecting all tested cell types,including lung epithelial cells. HTNV replicated in lung endothelial,heart,and brain cells,whereas SNV replication was largely confined to lung endothelial cells. Notably,ANDV infection induced stronger host transcriptional changes,promoted cell injury and inflammatory responses,and suppressed lipid metabolic pathways in lung epithelial cells. Further drug testing and pharmacotranscriptomic analysis identified effective inhibitors of ANDV infection,including urolithin B,that restored cellular metabolism with minimal transcriptional disruption. This study provides a comparative framework for understanding hantavirus cell tropism and host responses and highlights potential antiviral candidates for treating these severe viral infections. View Publication

IntroductionAmid the persistent threat of future pandemics,the continuous evolution of SARS-CoV-2 exposed critical challenges for vaccine efficacy and therapeutic interventions,highlighting the need for rapid and adaptable approaches to respond to immune escape variants.MethodsHere,we report the use of immortalized B cell libraries from human peripheral blood mononuclear cells (PBMCs) and tonsil tissues to uncover B cell clones exhibiting cross-reactive neutralization against various SARS-CoV-2 variants and perform directed evolution of immortalized B cell clones to produce antibodies with improved binding and neutralization against emerging SARS-CoV-2 variants.ResultsImmortalization of PBMC and tonsil-derived human B cells was achieved through transduction with retroviral vectors encoding apoptosis inhibitors,yielding transduction efficiencies of 67.5% for PBMCs and 50.2% for tonsil-derived cells. Analysis revealed that immortalized B cell libraries produced with this method retain diverse immunoglobulin isotype representations. Through high-throughput functional screening of approximately 40,000 B cells per library,we identified 12 unique clones with neutralization activity for SARS-CoV-2,leading to selection of monoclonal antibodies with robust neutralization activity against Delta and BA.5 variants. We applied our directed evolution approach to libraries generated by ex vivo AID-induced somatic hypermutation (SHM) of immortalized B cell clones to enhance the affinity and cross-reactivity,resulting in improved binding and neutralization potency to escape variants such as EG.5.1 and JN.1. Furthermore,we engineered a bi-paratopic antibody combining KBA2401,a broadly neutralizing antibody binding to highly conserved epitope on Spike-RBD,and KBA2402,a broadly binding non-neutralizing antibody,resulting in enhanced potency against SARS-CoV-2 variant JN.1 and KP.3.DiscussionOur findings illustrate the use of immortalized B cell libraries for development of therapeutics that adapt to viral evolution and highlight the application of ex vivo directed evolution in refining antibody responses against emerging immune escape SARS-CoV-2 variants. The approach here described offers a promising pathway for rapid therapeutic development in the face of evolving viral threats. View Publication

The selection of genetically engineered immune or hematopoietic cells in vivo after gene editing remains a clinical problem and requires a method to spare on-target toxicity to normal cells. Here,we develop a base editing approach exploiting a naturally occurring CD33 single nucleotide polymorphism leading to removal of full-length CD33 surface expression on edited cells. CD33 editing in human and nonhuman primate hematopoietic stem and progenitor cells protects myeloid progeny from CD33-targeted therapeutics without affecting normal hematopoiesis in vivo,thus demonstrating potential for improved immunotherapies with reduced off-leukemia toxicity. For broader application to gene therapies,we demonstrate highly efficient (>70%) multiplexed adenine base editing of the CD33 and gamma globin genes,resulting in long-term persistence of dual gene-edited cells with HbF reactivation in nonhuman primates. Using the CD33 antibody-drug conjugate Gemtuzumab Ozogamicin,we show resistance of engrafted,multiplex edited human cells in vivo,and a 2-fold enrichment for edited cells in vitro. Together,our results highlight the potential of adenine base editors for improved immune and gene therapies. Subject terms: Haematopoietic stem cells,Bone marrow transplantation,Cell biology View Publication

Reduced serum testosterone (T),or hypogonadism,affects millions of men and is associated with many pathologies,including infertility,cardiovascular diseases,metabolic syndrome,and decreased libido and sexual function. Administering T-replacement therapy (TRT) reverses many of the symptoms associated with low T levels. However,TRT is linked to side effects such as infertility and increased risk of prostate cancer and cardiovascular diseases. Thus,there is a need to obtain T-producing cells that could be used to treat hypogonadism via transplantation and reestablishment of T-producing cell lineages in the body. T is synthesized by Leydig cells (LCs),proposed to derive from mesenchymal cells of mesonephric origin. Although mesenchymal cells have been successfully induced into LCs,the limited source and possible trauma to donors hinders their application to clinical therapies. Alternatively,human induced pluripotent stem cells (hiPSCs),which are expandable in culture and have the potential to differentiate into all somatic cell types,have become the emerging source of autologous cell therapies. We have successfully induced the differentiation of hiPSCs into either human Leydig-like (hLLCs) or adrenal-like cells (hALCs) using chemically defined culture conditions. Factors critical for the development of LCs were added to both culture systems. hLLCs expressed all steroidogenic genes and proteins important for T biosynthesis,synthesized T rather than cortisol,secreted steroid hormones in response to dibutyryl-cAMP and 22(R)-hydroxycholesterol,and displayed ultrastructural features resembling LCs. By contrast,hALCs synthesized cortisol rather than T. The success in generating hiPSC-derived hLLCs with broad human LC (hLC) features supports the potential for hiPSC-based hLC regeneration. View Publication

Activating interferon responses with STING agonists (STINGa) is a current cancer immunotherapy strategy,and therapeutic modalities that enable tumor-targeted delivery via systemic administration could be beneficial. Here we demonstrate that tumor cell-directed STING agonist antibody-drug-conjugates (STINGa ADCs) activate STING in tumor cells and myeloid cells and induce anti-tumor innate immune responses in in vitro,in vivo (in female mice),and ex vivo tumor models. We show that the tumor cell-directed STINGa ADCs are internalized into myeloid cells by Fcγ-receptor-I in a tumor antigen-dependent manner. Systemic administration of STINGa ADCs in mice leads to STING activation in tumors,with increased anti-tumor activity and reduced serum cytokine elevations compared to a free STING agonist. Furthermore,STINGa ADCs induce type III interferons,which contribute to the anti-tumor activity by upregulating type I interferon and other key chemokines/cytokines. These findings reveal an important role for type III interferons in the anti-tumor activity elicited by STING agonism and provide rationale for the clinical development of tumor cell-directed STINGa ADCs. Activation of the STING pathway can promote anti-tumor immunity. Here the authors generate tumor cell-directed STING agonist antibody-drug conjugates that activate STING in tumor and myeloid cells,promoting anti-tumor innate immune responses in preclinical cancer models. View Publication

Although chimeric antigen receptor (CAR) T cells are effective against B-lineage malignancies,post-CAR relapse is common,and efficacy in other tumors is limited. These challenges may be addressed through rational manipulations to control CAR T cell function. Here we examine the impact of cognate T cell antigen experience on subsequent CD8+ CAR T cell activity. Prior antigen encounter resulted in superior effector function against leukemia expressing low target antigen density at the expense of reduced proliferative capacity and susceptibility to dysfunction at limiting CAR doses. Distinctive temporal transcriptomic and epigenetic profiles in naive-derived and memory-derived CAR T cells identified RUNX family transcription factors as potential targets to augment the function of naive-derived CD8+ CAR T cells. RUNX2 overexpression enhanced antitumor efficacy of mouse CAR T cells,dependent on prior cell state,and heightened human CAR T cell functions. Our data demonstrate that prior antigen experience of CAR T cells determines functional attributes and amenability to transcription factor-mediated functional enhancement. Here,Fry and colleagues examine the impact of antigen experience on subsequent CD8+ CAR T cell activity during the antileukemia response and show that RUNX2 overexpression enhances antitumor activity of these cells. View Publication

IntroductionT cells are major components of the immune system. Their activation requires interaction between the T cell receptor and co-stimulatory molecules,crucial during infection,inflammation,and allogeneic rejection. Monomeric CRP (mCRP) is a known modulator of inflammation and particularly the innate immune response,however its interaction with T cells as part of the adaptive immune response remains unclear.MethodsPeripheral blood mononuclear cells (PBMC) and T cells were isolated. Flow cytometric analysis was conducted to evaluate Fcγ receptor CD16 expression on T cells,the binding of CRP to T cells,and its impact on proliferation and apoptosis. T cell activation was assessed after 1,2,3,5 and 7 days by assessing CD69 and CD25 expression,and under various conditions including coculture with monocytes and several inhibitory factors.ResultsT cells express CD16 that binds mCRP in a concentration-dependent manner,and particularly on activated T cells. While mCRP reduces apoptosis and accelerates proliferation in T cells,it does not independently activate them. However,activation of monocytes by mCRP leads to T cell activation,indicating a direct cell to cell interaction during CRP-induced activation. This effect could be alleviated by inhibition of the CD80/CD28 pathway.ConclusionCRP does not activate T Cells directly but via PI3-kinase-dependent activation of monocytes and subsequent CD80/CD28 cell to cell contact. The findings suggest the effects of CRP on T cells depend on their environment and the presence of other proinflammatory agents. View Publication

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy characterized by desmoplastic stroma,immunosuppressive tumor microenvironment (TME),and resistance to standard therapies. Natural killer (NK) cell-based immunotherapies have shown limited efficacy due to impaired persistence,infiltration,and function in PDAC. Methods: We established a direct reprogramming strategy to generate cytotoxic NK cells (1 F-NKs) by targeting BCL11B,a transcription factor essential for T cell lineage commitment,using shRNA or CRISPR/Cas9 in peripheral blood mononuclear cells (PBMCs). A genome-wide CRISPR/Cas9 screen identified tumor-intrinsic modulators of NK resistance. Functional and in vivo studies assesses the efficacy of 1 F-NKs alone and in combination with mesothelin (MSLN)-CAR engineering and PKMYT1 inhibition. Results: BCL11B depletion enabled the generation of CD56brightCD16bright 1 F-NKs with potent cytotoxicity and elevated NKG2D and CX3CR1 expression. Site-specific integration of a mesothelin (MSLN)-CAR into BCL11B locus generated MSLN-1 F-NKs with stable antigen specific activity. A genome-wide screen identified PKMYT1 as a modulator of tumor resistance to NK cell-mediated killing; its inhibition by RP6306 upregulated NKG2D ligands (MICA/B) and CX3CL1,sensitizing PDACs to 1 F-NK cytotoxicity. In PDAC xenograft models,1 F-NKs alone or combined with CAR engineering and RP6306 significantly reduced tumor growth and prolonged survival. Notably,this triple combination elicited a synergistic antitumor effect,outperforming each monotherapy or dual combination. Conclusions: This study presents a synergistic immunotherapy platform that integrates NK reprogramming,CAR engineering,and tumor sensitization. The combinatorial approach significantly enhances antitumor efficacy in PDAC and offers a promising strategy for overcoming immune resistance in solid tumors. View Publication

Diseases affecting the kidney constitute a major health issue worldwide. Their incidence and poor prognosis affirm the urgent need for the development of new therapeutic strategies. Recently,differentiation of pluripotent cells to somatic lineages has emerged as a promising approach for disease modelling and cell transplantation. Unfortunately,differentiation of pluripotent cells into renal lineages has demonstrated limited success. Here we report on the differentiation of human pluripotent cells into ureteric-bud-committed renal progenitor-like cells. The generated cells demonstrated rapid and specific expression of renal progenitor markers on 4-day exposure to defined media conditions. Further maturation into ureteric bud structures was accomplished on establishment of a three-dimensional culture system in which differentiated human cells assembled and integrated alongside murine cells for the formation of chimeric ureteric buds. Altogether,our results provide a new platform for the study of kidney diseases and lineage commitment,and open new avenues for the future application of regenerative strategies in the clinic. View Publication

Human pluripotent stem cell (hPSC) differentiation typically yields heterogeneous populations. Knowledge of signals controlling embryonic lineage bifurcations could efficiently yield desired cell types through exclusion of alternate fates. Therefore,we revisited signals driving induction and anterior-posterior patterning of definitive endoderm to generate a coherent roadmap for endoderm differentiation. With striking temporal dynamics,BMP and Wnt initially specified anterior primitive streak (progenitor to endoderm),yet,24 hr later,suppressed endoderm and induced mesoderm. At lineage bifurcations,cross-repressive signals separated mutually exclusive fates; TGF-?? and BMP/MAPK respectively induced pancreas versus liver from endoderm by suppressing the alternate lineage. We systematically blockaded alternate fates throughout multiple consecutive bifurcations,thereby efficiently differentiating multiple hPSC lines exclusively into endoderm and its derivatives. Comprehensive transcriptional and chromatin mapping of highly pure endodermal populations revealed that endodermal enhancers existed in a surprising diversity of pre-enhancer" states before activation� View Publication

Human pluripotent stem cells (hPSCs) are a promising cell source with pluripotency and capacity to differentiate into all human somatic cell types. Designing simple and safe biomaterials with an innate ability to induce osteoblastic lineage from hPSCs is desirable to realize their clinical adoption in bone regenerative medicine. To address the issue,here we developed a fully defined synthetic peptides-decorated two dimensional (2D) microenvironment assisted via polydopamine (pDA) chemistry and subsequent carboxymethyl chitosan (CMC) grafting to enhance the culture and osteogenic potential of hPSCs in vitro. The hPSCs including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) were successfully cultured on the peptides-decorated surface without Matrigel- and ECM protein-coating and underwent promoted osteogenic differentiation in vitro,determined from the alkaline phosphate (ALP) activity,gene expression,and protein production as well as calcium deposit amount. It was found that directed osteogenic differentiation of hPSCs could be achieved through a peptides-decorated niche. This chemical-defined and safe 2D microenvironment which facilitates proliferation and osteo-differentiation of hPSCs,not only helps to accelerate the translational perspectives of hPSCs,but also provides tissue-specific functions such as directing stem cell differentiation commitment,having great potential in bone tissue engineering and presenting new avenues for bone regenerative medicine. View Publication