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

A rapid,ultrasensitive,and practical label-free impedimetric immunoassay for measuring trace levels of total polychlorinated biphenyls (PCBs) in insulating oil was developed. First,we developed a novel monoclonal antibody (RU6F9) for PCBs by using a designed immunogen and characterized its binding affinity for a commercial mixtures of PCBs and its main congeners. A micro comblike gold electrode was fabricated,and the antibody was covalently immobilized on the electrode through a self-assembled monolayer formed by dithiobis-N-succinimidyl propionate. The antigen-binding event on the surface of the functionalized electrode was determined as the change in charge transfer resistance by using electrochemical impedance spectroscopy. The resulting impedimetric immunoassay in aqueous solution achieved a wide determination range (0.01-10 μg/L) and a low detection limit (LOD) of 0.001 μg/L,which was 100-fold more sensitive than a conventional flow-based immunoassay for PCBs. By combining the impedimetric immunoassay with a cleanup procedure for insulating oil utilizing a multilayer cleanup column followed by DMSO partitioning,an LOD of 0.052 mg/kg-oil was achieved,which satisfied the Japanese regulation criterion of 0.5 mg/kg-oil. Finally,the immunoassay was employed to determine total PCB levels in actual used insulating oils (n = 33) sampled from a used transformer containing trace levels of PCBs,and the results agreed well with the Japanese official method (HRGC/HRMS). View Publication

The mechanisms by which megakaryocytes (MKs) differentiate and release platelets into the circulation are not well understood. However,growing evidence indicates that a complex regulatory mechanism involving MK-matrix interactions may contribute to the quiescent or permissive microenvironment related to platelet release within bone marrow. To address this hypothesis,in this study we demonstrate that human MKs express and synthesize cellular fibronectin (cFN) and transglutaminase factor XIII-A (FXIII-A). We proposed that these 2 molecules are involved in a new regulatory mechanism of MK-type I collagen interaction in the osteoblastic niche. In particular,we demonstrate that MK adhesion to type I collagen promotes MK spreading and inhibits pro-platelet formation through the release and relocation to the plasma membrane of cFN. This regulatory mechanism is dependent on the engagement of FN receptors at the MK plasma membrane and on transglutaminase FXIII-A activity. Consistently,the same mechanism regulated the assembly of plasma FN (pFN) by adherent MKs to type I collagen. In conclusion,our data extend the knowledge of the mechanisms that regulate MK-matrix interactions within the bone marrow environment and could serve as an important step for inquiring into the origins of diseases such as myelofibrosis and congenital thrombocytopenias that are still poorly understood. View Publication

BackgroundPrimary cilia mediate vertebrate development and growth factor signalling. Defects in primary cilia cause inherited developmental conditions termed ciliopathies. Ciliopathies often present with cystic kidney disease,a major cause of early renal failure. Currently,only one drug,Tolvaptan,is licensed to slow the decline of renal function for the ciliopathy polycystic kidney disease. Novel therapeutic interventions are needed.MethodsWe screened clinical development compounds to identify those that reversed cilia loss due to siRNA knockdown. In parallel,we undertook a whole genome siRNA-based reverse genetics phenotypic screen to identify positive modulators of cilia formation.ResultsUsing a clinical development compound screen,we identify fasudil hydrochloride. Fasudil is a generic,off-patent drug that is a potent,broadly selective Rho-associated coiled-coil-containing protein kinase (ROCK) inhibitor. In parallel,the siRNA screen identifies ROCK2 and we demonstrate that ROCK2 is a key mediator of cilium formation and function through its possible effects on actin cytoskeleton remodelling.ConclusionsOur results indicate that specific ROCK2 inhibitors (e.g. belumosudil) could be repurposed for cystic kidney disease treatment. We propose that ROCK2 inhibition represents a novel,disease-modifying therapeutic approach for heterogeneous ciliopathies. Plain language summaryPrimary cilia are antennae-like structures on cells that are important for early development and healthy cell function. Defects in primary cilia can cause inherited diseases called ciliopathies. Ciliopathies often cause fluid-filled sacs,called cysts,that are a major cause of kidney disease and failure. There is currently one drug licensed to slow kidney disease progression,but it is poorly tolerated in patients. Therefore,new drugs are needed. In this study,we used screening assays to identify potential drugs and their targets that are effective in promoting the formation of primary cilia. Our results identified ROCK2 (Rho-associated coiled-coil-containing protein kinase 2),an inhibitor of protein signalling,as a key mediator of cilium function. These findings suggest that drugs that specifically target ROCK2 could be a potential treatment option for cystic kidney disease. Smith et al. use clinical development screen and whole genome siRNA-reverse genetics phenotypic screen to identify ROCK2,as a modulator of cilia formation and function via its effects on actin cytoskeleton remodelling. Repurposing ROCK2 is a viable treatment for ciliopathies,for which a limited therapeutic option is available. View Publication

T cell-derived cancers are hallmarked by heterogeneity,aggressiveness,and poor clinical outcomes. Available targeted therapies are severely limited due to a lack of target antigens that allow discrimination of malignant from healthy T cells. Here,we report a novel approach for the treatment of T cell diseases based on targeting the clonally rearranged T cell receptor displayed by the cancerous T cell population. As a proof of concept,we identified an antibody with unique specificity toward a distinct T cell receptor (TCR) and developed antibody-drug conjugates,precisely recognizing and eliminating target T cells while preserving overall T cell repertoire integrity and cellular immunity. Our anti-TCR antibody-drug conjugates demonstrated effective receptor-mediated cell internalization,associated with induction of cancer cell death with strong signs of apoptosis. Furthermore,cell proliferation-inhibiting bystander effects observed on target-negative cells may contribute to the molecules’ anti-tumor properties precluding potential tumor escape mechanisms. To our knowledge,this represents the first anti-TCR antibody-drug conjugate designed as custom-tailored immunotherapy for T cell-driven pathologies. Graphical abstract Harald Kolmar and colleagues report a novel approach for the treatment of the difficult-to-treat T cell lymphoma/leukemia based on targeting the clonally rearranged T cell receptor expressed by the malignant T cell population. The developed antibody-drug conjugates precisely eliminate target T cells while preserving the integrity of the T cell repertoire and cellular immunity. View Publication

Telomeres as the protective ends of linear chromosomes,are synthesized by the enzyme telomerase (TERT). Critically short telomeres essentially contribute to aging-related diseases and are associated with a broad spectrum of disorders known as telomeropathies. In cardiomyocytes,telomere length is strongly correlated with cardiomyopathies but it remains ambiguous whether short telomeres are the cause or the result of the disease. In this study,we employed an inducible CRISPRi human induced pluripotent stem cell (hiPSC) line to silence TERT expression enabling the generation of hiPSCs and hiPSC-derived cardiomyocytes with long and short telomeres. Reduced telomerase activity and shorter telomere lengths of hiPSCs induced global transcriptomic changes associated with cardiac developmental pathways. Consequently,the differentiation potential towards cardiomyocytes was strongly impaired and single cell RNA sequencing revealed a shift towards a more smooth muscle cell like identity in the cells with the shortest telomeres. Poor cardiomyocyte function and increased sensitivity to stress directly correlated with the extent of telomere shortening. Collectively our data demonstrates a TERT dependent cardiomyogenic differentiation defect,highlighting the CRISPRi TERT hiPSCs model as a powerful platform to study the mechanisms and consequences of short telomeres in the heart and also in the context of telomeropathies. The online version contains supplementary material available at 10.1007/s00018-024-05239-7. View Publication

Many biological tissues,such as cardiac muscle,tendons,and the cornea,exhibit highly organized microstructural alignment that is critical for mechanical and physiological functions. Disruptions in this structural organization are commonly associated with pathological conditions such as fibrosis,infarction,and cancer. However,conventional histological imaging techniques rely on immunofluorescence or histochemical staining,and they evaluate tissue alignment via non-physical 2D gradient-based calculation,which is labor-intensive,antibody-dependent,and prone to variability. Here,we demonstrate label-free mid-infrared dichroism-sensitive photoacoustic microscopy (MIR-DS-PAM),an analytical imaging system for cardiac tissue assessments. By combining molecular specificity with polarization sensitivity,this method selectively visualizes protein-rich engineered heart tissue (EHT) and quantifies the extracellular matrix (ECM) alignment without any labeling. The extracted dichroism-sensitive parameters,such as the degree of dichroism and the orientation angle,enable histostructural evaluation of tissue integrity and reveal diagnostic cues in fibrotic EHT. This technique offers a label-free analytical tool for fibrosis research and tissue engineering applications. Mid-infrared dichroism-sensitive photoacoustic microscopy enables label-free,quantitative histostructural analysis by combining spectral specificity and polarization sensitivity to visualize protein-rich components and evaluate anisotropic tissue alignment. View Publication

Cardiac progenitor cells (CPCs) have the capacity to differentiate into cardiomyocytes,smooth muscle cells (SMC),and endothelial cells and hold great promise in cell therapy against heart disease. Among various methods to isolate CPCs,differentiation of embryonic stem cell (ESC) into CPCs attracts great attention in the field since ESCs can provide unlimited cell source. As a result,numerous strategies have been developed to derive CPCs from ESCs. In this protocol,differentiation and purification of embryonic CPCs from both mouse and human ESCs is described. Due to the difficulty of using cell surface markers to isolate embryonic CPCs,ESCs are engineered with fluorescent reporters activated by CPC-specific cre recombinase expression. Thus,CPCs can be enriched by fluorescence-activated cell sorting (FACS). This protocol illustrates procedures to form embryoid bodies (EBs) from ESCs for CPC specification and enrichment. The isolated CPCs can be subsequently cultured for cardiac lineage differentiation and other biological assays. This protocol is optimized for robust and efficient derivation of CPCs from both mouse and human ESCs. View Publication

Hematologic stem cell rescue after high-dose cytotoxic therapy is extensively used for the treatment of many hematopoietic and solid cancers. Gene marking studies suggest that occult tumor cells within the autograft may contribute to clinical relapse. To date purging of autografts contaminated with cancer cells has been unsuccessful. The selective oncolytic property of reovirus against myriad malignant histologies in in vitro,in vivo,and ex vivo systems has been previously demonstrated. In the present study we have shown that reovirus can successfully purge cancer cells within autografts. Human monocytic and myeloma cell lines as well as enriched ex vivo lymphoma,myeloma,and Waldenström macroglobulinemia patient tumor specimens were used in an experimental purging model. Viability of the cell lines or purified ex vivo tumor cells of diffuse large B-cell lymphoma,chronic lymphocytic leukemia,Waldenström macroglobulinemia,and small lymphocytic lymphoma was significantly reduced after reovirus treatment. Further,[35S]-methionine labeling and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of cellular proteins demonstrated reovirus protein synthesis and disruption of host cell protein synthesis as early as 24 hours. Admixtures of apheresis product with the abovementioned tumor cells and cell lines treated with reovirus showed complete purging of disease. In contrast,reovirus purging of enriched ex vivo multiple myeloma,Burkitt lymphoma,and follicular lymphoma was incomplete. The oncolytic action of reovirus did not affect CD34+ stem cells or their long-term colony-forming assays even after granulocyte colony-stimulating factor (G-CSF) stimulation. Our results indicate the ex vivo use of an unattenuated oncolytic virus as an attractive purging strategy for autologous stem cell transplantations. View Publication

The chicken anemia virus-derived protein apoptin induces apoptosis in a variety of human malignant and transformed cells but not in normal cells. However,the mechanisms through which apoptin achieves its selective killing effects are not well understood. We developed a lentiviral vector encoding a green fluorescent protein-apoptin fusion gene (LV-GFP-AP) that can efficiently deliver apoptin into hematopoietic cells. Apoptin selectively killed the human multiple myeloma cell lines MM1.R and MM1.S,and the leukemia cell lines K562,HL60,U937,KG1,and NB4. In contrast,normal CD34(+) cells were not killed and maintained their differentiation potential in multilineage colony formation assays. In addition,dexamethasone-resistant MM1.R cells were found to be more susceptible to apoptin-induced cell death than the parental matched MM1.S cells. Death susceptibility correlated with increased phosphorylation and activation of the apoptin protein in MM1.R cells. Expression array profiling identified differential kinase profiles between MM1.R and MM1.S cells. Among these kinases,protein kinase Cβ (PKCβ) was found by immunoprecipitation and in vitro kinase studies to be a candidate kinase responsible for apoptin phosphorylation. Indeed,shRNA knockdown or drug-mediated inhibition of PKCβ significantly reduced apoptin phosphorylation. Furthermore,apoptin-mediated cell death proceeded through the upregulation of PKCβ,activation of caspase-9/3,cleavage of the PKCδ catalytic domain,and downregulation of the MERTK and AKT kinases. Collectively,these results elucidate a novel pathway for apoptin activation involving PKCβ and PKCδ. Further,they highlight the potential of apoptin and its cellular regulators to purge bone marrow used in autologous transplantation for multiple myeloma. View Publication

Disruptor of telomeric silencing 1-like (Dot1l) is a histone 3 lysine 79 methyltransferase. Studies of constitutive Dot1l knockout mice show that Dot1l is essential for embryonic development and prenatal hematopoiesis. DOT1L also interacts with translocation partners of Mixed Lineage Leukemia (MLL) gene,which is commonly translocated in human leukemia. However,the requirement of Dot1l in postnatal hematopoiesis and leukemogenesis of MLL translocation proteins has not been conclusively shown. With a conditional Dot1l knockout mouse model,we examined the consequences of Dot1l loss in postnatal hematopoiesis and MLL translocation leukemia. Deletion of Dot1l led to pancytopenia and failure of hematopoietic homeostasis,and Dot1l-deficient cells minimally reconstituted recipient bone marrow in competitive transplantation experiments. In addition,MLL-AF9 cells required Dot1l for oncogenic transformation,whereas cells with other leukemic oncogenes,such as Hoxa9/Meis1 and E2A-HLF,did not. These findings illustrate a crucial role of Dot1l in normal hematopoiesis and leukemogenesis of specific oncogenes. View Publication

Lymphatic endothelial cells (LECs) chemoattract na{\{i}}ve T cells and promote their survival in the lymph nodes and can cross-present antigens to na{\"{i}}ve CD8+ T cells to drive their proliferation despite lacking key costimulatory molecules. However the functional consequence of LEC priming of CD8+ T cells is unknown. Here we show that while many proliferating LEC-educated T cells enter early apoptosis the remainders comprise a long-lived memory subset with transcriptional metabolic and phenotypic features of central memory and stem cell-like memory T cells. In vivo these memory cells preferentially home to lymph nodes and display rapid proliferation and effector differentiation following memory recall and can protect mice against a subsequent bacterial infection. These findings introduce a new immunomodulatory role for LECs in directly generating a memory-like subset of quiescent yet antigen-experienced CD8+ T cells that are long-lived and can rapidly differentiate into effector cells upon inflammatory antigenic challenge.""" View Publication

Diffuse intrinsic pontine gliomas (DIPGs) represent a particularly lethal type of pediatric brain cancer with no effective therapeutic options. Our laboratory has previously reported the development of genetically engineered DIPG mouse models using the RCAS/tv-a system,including a model driven by PDGF-B,H3.3K27M,and p53 loss. These models can serve as a platform in which to test novel therapeutics prior to the initiation of human clinical trials. In this study,an in vitro high-throughput drug screen as part of the DIPG preclinical consortium using cell-lines derived from our DIPG models identified BMS-754807 as a drug of interest in DIPG. BMS-754807 is a potent and reversible small molecule multi-kinase inhibitor with many targets including IGF-1R,IR,MET,TRKA,TRKB,AURKA,AURKB. In vitro evaluation showed significant cytotoxic effects with an IC50 of 0.13 μM,significant inhibition of proliferation at a concentration of 1.5 μM,as well as inhibition of AKT activation. Interestingly,IGF-1R signaling was absent in serum-free cultures from the PDGF-B; H3.3K27M; p53 deficient model suggesting that the antitumor activity of BMS-754807 in this model is independent of IGF-1R. In vivo,systemic administration of BMS-754807 to DIPG-bearing mice did not prolong survival. Pharmacokinetic analysis demonstrated that tumor tissue drug concentrations of BMS-754807 were well below the identified IC50,suggesting that inadequate drug delivery may limit in vivo efficacy. In summary,an unbiased in vitro drug screen identified BMS-754807 as a potential therapeutic agent in DIPG,but BMS-754807 treatment in vivo by systemic delivery did not significantly prolong survival of DIPG-bearing mice. View Publication