搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

BACKGROUND Chronic kidney disease patients are at increased risk of mortality with cardiovascular diseases and infections as the two leading causes of death for end-stage kidney disease treated with hemodialysis (HD). Mortality from bacterial infections in HD patients is estimated to be 100-1000 times higher than in the healthy population. METHODS We comprehensively characterized highly pure circulating neutrophils from HD and healthy donors. RESULTS Protein levels and transcriptome of HD patients' neutrophils indicated massive neutrophil degranulation with a dramatic reduction in reactive oxygen species (ROS) production during an oxidative burst and defective oxidative cellular signaling. Moreover,HD neutrophils exhibit severely impaired ability to generate extracellular NET formation (NETosis) in NADPH oxidase-dependent or independent pathways,reflecting their loss of capacity to kill extracellular bacteria. Ectopic hydrogen peroxidase (H2O2) or recombinant human SOD-1 (rSOD-1) partly restores and improves the extent of HD dysfunctional neutrophil NET formation. CONCLUSIONS Our report is one of the first singular examples of severe and chronic impairment of NET formation leading to substantial clinical susceptibility to bacteremia that most likely results from the metabolic and environmental milieu typical to HD patients and not by common human genetic deficiencies. In this manner,aberrant gene expression and differential exocytosis of distinct granule populations could reflect the chronic defect in neutrophil functionality and their diminished ability to induce NETosis. Therefore,our findings suggest that targeting NETosis in HD patients may reduce infections,minimize their severity,and decrease the mortality rate from infections in this patient population. View Publication

BACKGROUND Novel therapies are urgently needed for ovarian cancer (OC),the fifth deadliest cancer in women. Preclinical work has shown that DNA methyltransferase inhibitors (DNMTis) can reverse the immunosuppressive tumor microenvironment in OC. Inhibiting DNA methyltransferases activate transcription of double-stranded (ds)RNA,including transposable elements. These dsRNAs activate sensors in the cytoplasm and trigger type I interferon (IFN) signaling,recruiting host immune cells to kill the tumor cells. Adenosine deaminase 1 (ADAR1) is induced by IFN signaling and edits mammalian dsRNA with an A-to-I nucleotide change,which is read as an A-to-G change in sequencing data. These edited dsRNAs cannot be sensed by dsRNA sensors,and thus ADAR1 inhibits the type I IFN response in a negative feedback loop. We hypothesized that decreasing ADAR1 editing would enhance the DNMTi-induced immune response. METHODS Human OC cell lines were treated in vitro with DNMTi and then RNA-sequenced to measure RNA editing. Adar1 was stably knocked down in ID8 Trp53-/- mouse OC cells. Control cells (shGFP) or shAdar1 cells were tested with mock or DNMTi treatment. Tumor-infiltrating immune cells were immunophenotyped using flow cytometry and cell culture supernatants were analyzed for secreted chemokines/cytokines. Mice were injected with syngeneic shAdar1 ID8 Trp53-/- cells and treated with tetrahydrouridine/DNMTi while given anti-interferon alpha and beta receptor 1,anti-CD8,or anti-NK1.1 antibodies every 3 days. RESULTS We show that ADAR1 edits transposable elements in human OC cell lines after DNMTi treatment in vitro. Combining ADAR1 knockdown with DNMTi significantly increases pro-inflammatory cytokine/chemokine production and sensitivity to IFN-$\beta$ compared with either perturbation alone. Furthermore,DNMTi treatment and Adar1 loss reduces tumor burden and prolongs survival in an immunocompetent mouse model of OC. Combining Adar1 loss and DNMTi elicited the most robust antitumor response and transformed the immune microenvironment with increased recruitment and activation of CD8+ T cells. CONCLUSION In summary,we showed that the survival benefit from DNMTi plus ADAR1 inhibition is dependent on type I IFN signaling. Thus,epigenetically inducing transposable element transcription combined with inhibition of RNA editing is a novel therapeutic strategy to reverse immune evasion in OC,a disease that does not respond to current immunotherapies. View Publication

The blood?brain barrier (BBB) is a critical selective interface between the central nervous system (CNS) and the blood circulation. BBB dysfunction plays an important role in the neurological damage caused by sepsis. However,the mechanisms underlying the disruption of the BBB during sepsis remain unclear. We established a human induced pluripotent stem cell (iPSC)-derived BBB model and reported that treating with sepsis patient serum leads to structural and functional disruption of the BBB. In a cecal ligation and puncture (CLP)-induced mouse model of sepsis,we also observed disruption of the BBB,inflammation in the brain,and impairments in cognition. In both models,we found that the expression of TREM-1 was significantly increased in endothelial cells. TREM-1 knockout specifically in endothelial cells alleviated BBB dysfunction and cognitive impairments. Further study revealed that TREM-1 affects the expression of genes involved in the PI3K/Akt signaling pathway. The protective effects of TREM-1 inhibition on the BBB and cognition were abrogated by PI3K inhibitors. Our findings suggest that endothelial TREM-1 induces sepsis-induced BBB disruption and cognitive impairments via the PI3K/Akt signaling pathway. Targeting endothelial TREM-1 or the PI3K/Akt signaling pathway may be a promising strategy to maintain BBB integrity and improve cognitive function in sepsis patients.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12974-025-03469-5. View Publication

The work highlights the different calcium channels involved in controlling protein synthesis in neurons,and shows the dysfunction of this process in Alzheimer’s disease neurons. Calcium signaling is integral for neuronal activity and synaptic plasticity. We demonstrate that the calcium response generated by different sources modulates neuronal activity–mediated protein synthesis,another process essential for synaptic plasticity. Stimulation of NMDARs generates a protein synthesis response involving three phases—increased translation inhibition,followed by a decrease in translation inhibition,and increased translation activation. We show that these phases are linked to NMDAR-mediated calcium response. Calcium influx through NMDARs elicits increased translation inhibition,which is necessary for the successive phases. Calcium through L-VGCCs acts as a switch from translation inhibition to the activation phase. NMDAR-mediated translation activation requires the contribution of L-VGCCs,RyRs,and SOCE. Furthermore,we show that IP3-mediated calcium release and SOCE are essential for mGluR-mediated translation up-regulation. Finally,we signify the relevance of our findings in the context of Alzheimer’s disease. Using neurons derived from human fAD iPSCs and transgenic AD mice,we demonstrate the dysregulation of NMDAR-mediated calcium and translation response. Our study highlights the complex interplay between calcium signaling and protein synthesis,and its implications in neurodegeneration. View Publication

BackgroundThree common isoforms of the apolipoprotein E (APOE) gene - APOE2,APOE3,and APOE4 - hold varying significance in Alzheimer’s Disease (AD) risk. The APOE4 allele is the strongest known genetic risk factor for late-onset Alzheimer’s Disease (AD),and its expression has been shown to correlate with increased central nervous system (CNS) amyloid deposition and accelerated neurodegeneration. Conversely,APOE2 is associated with reduced AD risk and lower CNS amyloid burden. Recent clinical data have suggested that increased blood-brain barrier (BBB) leakage is commonly observed among AD patients and APOE4 carriers. However,it remains unclear how different APOE isoforms may impact AD-related pathologies at the BBB.MethodsTo explore potential impacts of APOE genotypes on BBB properties and BBB interactions with amyloid beta,we differentiated isogenic human induced pluripotent stem cell (iPSC) lines with different APOE genotypes into both brain microvascular endothelial cell-like cells (BMEC-like cells) and brain pericyte-like cells. We then compared the effect of different APOE isoforms on BBB-related and AD-related phenotypes. Statistical significance was determined via ANOVA with Tukey’s post hoc testing as appropriate.ResultsIsogenic BMEC-like cells with different APOE genotypes had similar trans-endothelial electrical resistance,tight junction integrity and efflux transporter gene expression. However,recombinant APOE4 protein significantly impeded the “brain-to-blood” amyloid beta 1–40 (A?40) transport capabilities of BMEC-like cells,suggesting a role in diminished amyloid clearance. Conversely,APOE2 increased amyloid beta 1–42 (A?42) transport in the model. Furthermore,we demonstrated that APOE-mediated amyloid transport by BMEC-like cells is dependent on LRP1 and p-glycoprotein pathways,mirroring in vivo findings. Pericyte-like cells exhibited similar APOE secretion levels across genotypes,yet APOE4 pericyte-like cells showed heightened extracellular amyloid deposition,while APOE2 pericyte-like cells displayed the least amyloid deposition,an observation in line with vascular pathologies in AD patients.ConclusionsWhile APOE genotype did not directly impact general BMEC or pericyte properties,APOE4 exacerbated amyloid clearance and deposition at the model BBB. Conversely,APOE2 demonstrated a potentially protective role by increasing amyloid transport and decreasing deposition. Our findings highlight that iPSC-derived BBB models can potentially capture amyloid pathologies at the BBB,motivating further development of such in vitro models in AD modeling and drug development.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12987-024-00580-2. View Publication

IntroductionGlucose Transporter 1-Deficiency Syndrome (GLUT1-DS) is a rare genetic disorder caused by mutations in the gene encoding for GLUT1 and characterized by impaired glucose uptake in the brain. This leads to brain hypometabolism and the development of symptoms that include epilepsy,motor dysfunctions and cognitive impairment. The development of patient-specific in vitro models is a valuable tool for understanding the pathophysiology of rare genetic disorders and testing new therapeutic interventions.MethodsIn this study,we generated brain organoids from induced pluripotent stem cells (iPSCs) derived either from a GLUT1-DS patient or a healthy individual. The functional organoids were analyzed for cellular composition,maturity,and electrophysiological activity using a custom-made microelectrode array (MEA) platform,which allowed for the detection of spikes,burst patterns,and epileptiform discharges.ResultsImmunostaining revealed a similar distribution of neurons and astrocytes in both healthy and GLUT1-DS brain organoids,though GLUT1-DS brain organoids exhibited reduced cellular density and smaller overall size. Electrophysiological recordings demonstrated functional spike profiles in both organoid types. Notably,our study demonstrates that brain organoids derived from a GLUT1-DS patient exhibit distinct epileptiform activity and heightened sensitivity to glucose deprivation,reflecting key features of the disorder.DiscussionThese findings validate the use of brain organoids as a model for studying GLUT1-DS and highlight their potential for testing novel therapeutic strategies aimed at improving glucose metabolism and managing epilepsy in patients. View Publication

Venoms comprise highly sophisticated bioactive molecules modulating ion channels,receptors,coagulation factors,and the cellular membranes. This array of targets and bioactivities requires advanced high-content bioassays to facilitate the development of novel envenomation treatments and biotechnological and pharmacological agents. In response to the existing gap in venom research,we developed a cutting-edge fluorescence-based high-throughput and high-content cellular assay. This assay enables the simultaneous identification of prevalent cellular activities induced by venoms such as membrane lysis,pore formation,and ion channel modulation. By integrating intracellular calcium with extracellular nucleic acid measurements,we have successfully distinguished these venom mechanisms within a single cellular assay. Our high-content bioassay was applied across three cell types exposed to venom components representing lytic,ion pore-forming or ion channel modulator toxins. Beyond unveiling distinct profiles for these action mechanisms,we found that the pore-forming latrotoxin ?-Lt1a prefers human neuroblastoma to kidney cells and cardiomyocytes,while the lytic bee peptide melittin is not selective. Furthermore,evaluation of snake venoms showed that Elapid species induced rapid membrane lysis,while Viper species showed variable to no activity on neuroblastoma cells. These findings underscore the ability of our high-content bioassay to discriminate between clades and interspecific traits,aligning with clinical observations at venom level,beyond discriminating among ion pore-forming,membrane lysis and ion channel modulation. We hope our research will expedite the comprehension of venom biology and the diversity of toxins that elicit cytotoxic,cardiotoxic and neurotoxic effects,and assist in identifying venom components that hold the potential to benefit humankind. Graphical abstractImage 1 Highlights•Optimization of bioassays to study venoms strengthens the discovery of novel drugs and envenomation treatments•We developed a high-content bioassay measuring DNA and [Ca2+]i that investigates multiple mechanisms in venom biology•This bioassay monitored membrane integrity,ion channels and ion pore formation to unravel venom's mechanism of action•We found the latrotoxin ?-Lt1a strikingly prefers neuron-like cells while the ?-helical melittin is non-selective•Evaluation of Elapid and Viper snake venoms demonstrates that this bioassay predicts the phylogeny and clinical findings View Publication

ABSTRACTGenetic variants in multiple sphingolipid biosynthesis genes cause human brain disorders. A recent study looked at people from 12 unrelated families with variants in the gene SMPD4,a neutral sphingomyelinase that metabolizes sphingomyelin into ceramide at an early stage of the biosynthesis pathway. These individuals have severe developmental brain malformations,including microcephaly and cerebellar hypoplasia. The disease mechanism of SMPD4 was not known and so we pursued a new mouse model. We hypothesized that the role of SMPD4 in producing ceramide is important for making primary cilia,a crucial organelle mediating cellular signaling. We found that the mouse model has cerebellar hypoplasia due to failure of Purkinje cell development. Human induced pluripotent stem cells lacking SMPD4 exhibit neural progenitor cell death and have shortened primary cilia,which is rescued by adding exogenous ceramide. SMPD4 production of ceramide is crucial for human brain development. Summary: Mouse and human stem cell models of SMPD4 loss of function demonstrate that SMPD4 promotes cilia function and neural development. View Publication

IntroductionBAP1 is a deubiquitinase (DUB) of the Ubiquitin C-terminal Hydrolase (UCH) family that regulates gene expression and other cellular processes,through its direct catalytic activity on the repressive epigenetic mark histone H2AK119ub,as well as on several other substrates. BAP1 is also a highly important tumor suppressor,expressed and functional across many cell types and tissues. In recent work,we demonstrated a cell intrinsic role of BAP1 in the B cell lineage development in murine bone marrow,however the role of BAP1 in the regulation of B cell mediated humoral immune response has not been previously explored. Methods and resultsIn the current study,we demonstrate that a B-cell intrinsic loss of BAP1 in activated B cells in the Bap1 fl/fl Cγ1-cre murine model results in a severe defect in antibody production,with altered dynamics of germinal centre B cell,memory B cell,and plasma cell numbers. At the cellular and molecular level,BAP1 was dispensable for B cell immunoglobulin class switching but resulted in an impaired proliferation of activated B cells,with genome-wide dysregulation in histone H2AK119ub levels and gene expression. Conclusion and discussionIn summary,our study establishes the B-cell intrinsic role of BAP1 in antibody mediated immune response and indicates its central role in the regulation of the genome-wide landscapes of histone H2AK119ub and downstream transcriptional programs of B cell activation and humoral immunity. View Publication

Humanized mice are limited in terms of modeling human immunity,particularly with regards to antibody responses. Here we constructed a humanized (THX) mouse by grafting non-γ-irradiated,genetically myeloablated KitW-41J mutant immunodeficient pups with human cord blood CD34+ cells,followed by 17β-estradiol conditioning to promote immune cell differentiation. THX mice reconstitute a human lymphoid and myeloid immune system,including marginal zone B cells,germinal center B cells,follicular helper T cells and neutrophils,and develop well-formed lymph nodes and intestinal lymphoid tissue,including Peyer’s patches,and human thymic epithelial cells. These mice have diverse human B cell and T cell antigen receptor repertoires and can mount mature T cell-dependent and T cell-independent antibody responses,entailing somatic hypermutation,class-switch recombination,and plasma cell and memory B cell differentiation. Upon flagellin or a Pfizer-BioNTech coronavirus disease 2019 (COVID-19) mRNA vaccination,THX mice mount neutralizing antibody responses to Salmonella or severe acute respiratory syndrome coronavirus 2 Spike S1 receptor-binding domain,with blood incretion of human cytokines,including APRIL,BAFF,TGF-β,IL-4 and IFN-γ,all at physiological levels. These mice can also develop lupus autoimmunity after pristane injection. By leveraging estrogen activity to support human immune cell differentiation and maturation of antibody responses,THX mice provide a platform to study the human immune system and to develop human vaccines and therapeutics. Humanized mice have been a valuable tool for modeling human immunology but are limited in their ability to model human antibody responses. Here the authors present their THX humanized mouse that does model human antibody responses and test its suitability for vaccination and autoimmunity studies. View Publication