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

The receptor tyrosine kinase c-Kit plays a critical role in hematopoiesis,and gain-of-function mutations of the receptor are frequently seen in several malignancies,including acute myeloid leukemia,gastrointestinal stromal tumors,and testicular carcinoma. The most common mutation of c-Kit in these disorders is a substitution of the aspartic acid residue in position 816 to a valine (D816V),leading to constitutive activation of the receptor. In this study,we aimed to investigate the role of Src family kinases in c-Kit/D816V signaling. Src family kinases are necessary for the phosphorylation of wild-type c-Kit as well as of activation of downstream signaling pathways including receptor ubiquitination and the Ras/Mek/Erk pathway. Our data demonstrate that,unlike wild-type c-Kit,the phosphorylation of c-Kit/D816V is not dependent on Src family kinases. In addition,we found that neither receptor ubiquitination nor Erk activation by c-Kit/D816V required activation of Src family kinases. In vitro kinase assay using synthetic peptides revealed that c-Kit/D816V had an altered substrate specificity resembling Src and Abl tyrosine kinases. We further present evidence that,in contrast to wild-type c-Kit,Src family kinases are dispensable for c-Kit/D816V cell survival,proliferation,and colony formation. Taken together,we demonstrate that the signal transduction pathways mediated by c-Kit/D816V are markedly different from those activated by wild-type c-Kit and that altered substrate specificity of c-Kit circumvents a need for Src family kinases in signaling of growth and survival,thereby contributing to the transforming potential of c-Kit/D816V. View Publication

To investigate the influence of antibody structure and specificity on antibody efficacy against Streptococcus pneumoniae,human monospecific antibodies (MAbs) to serotype 3 pneumococcal capsular polysaccharide (PPS-3) were generated from transgenic mice reconstituted with human immunoglobulin loci (XenoMouse mice) vaccinated with a PPS-3-tetanus toxoid conjugate and their molecular genetic structures,epitope specificities,and protective efficacies in normal and complement-deficient mice were determined. Nucleic acid sequence analysis of three MAbs (A7,1A2,and 7C5) revealed that they use two different V(H)3 genes (A7 and 1A2 both use V3-15) and three different V(kappa) gene segments. The MAbs were found to have similar affinities for PPS-3 but different epitope specificities and CDR3 regions. Both A7 and 7C5 had a lysine at the V(H)-D junction,whereas 1A2 had a threonine. Challenge experiments with serotype 3 S. pneumoniae in BALB/c mice revealed that both 10- and 1- micro g doses of A7 and 7C5 were protective,while only a 10- micro g dose of 1A2 was protective. Both A7 and 7C5 were also protective in mice lacking either an intact alternative (FB(-/-)) or classical (C4(-/-)) complement pathway,but 1A2 was not protective in either strain. Our data suggest that PPS-3 consists of epitopes that can elicit both highly protective and less protective antibodies and that the superior efficacies of certain antibodies may be a function of their structures and/or specificities. Further investigation of relationships between structure,specificity,and efficacy for defined MAbs to PPS may identify antibody features that might be useful surrogates for antibody (and vaccine) efficacy. View Publication

Cell type-specific surface markers offer a powerful tool for purifying defined cell types for restorative therapies and drug screenings. Midbrain dopaminergic neurons (mesDA) are the nerve cells preferentially lost in the brains of Parkinson's disease patients. Clinical trials of transplantation of fetal neural precursors suggest that cell therapy may offer a cure for this devastating neurological disease. Many lines of preclinical studies demonstrate that neural progenitors committed to dopaminergic fate survive and integrate better than postmitotic DA neurons. We show that the folate-receptor 1 (FolR1),a GPI-anchored cell surface molecule,specifically marks mesDA neural progenitors and immature mesDA neurons. FolR1 expression superimposes with Lmx1a,a bona-fide mesDA lineage marker,during the active phase of mesDA neurogenesis from E9.5 to E14.5 during mouse development,as well as in ESC-derived mesDA lineage. FolR1(+) neural progenitors can be isolated by FACS or magnetic sorting (MAC) which give rise to dopamine neurons expressing TH and Pitx3,whilst FolR1 negative cells generate non-dopaminergic neurons and glia cells. This study identifies FolR1 as a new cell surface marker selectively expressed in mesDA progenitors in vivo and in vitro and that can be used to enrich in vitro differentiated TH neurons. View Publication

When transmitted through the oral route,Toxoplasma gondii first interacts with its host at the small intestinal epithelium. This interaction is crucial to controlling initial invasion and replication,as well as shaping the quality of the systemic immune response. It is therefore an attractive target for the design of novel vaccines and adjuvants. However,due to a lack of tractable infection models,we understand surprisingly little about the molecular pathways that govern this interaction. The in vitro culture of small intestinal epithelium as 3D enteroids shows great promise for modeling the epithelial response to infection. However,the enclosed luminal space makes the application of infectious agents to the apical epithelial surface challenging. Here,we have developed three novel enteroid-based techniques for modeling T. gondii infection. In particular,we have adapted enteroid culture protocols to generate collagen-supported epithelial sheets with an exposed apical surface. These cultures retain epithelial polarization,and the presence of fully differentiated epithelial cell populations. They are susceptible to infection with,and support replication of,T. gondii. Using quantitative label-free mass spectrometry,we show that T. gondii infection of the enteroid epithelium is associated with up-regulation of proteins associated with cholesterol metabolism,extracellular exosomes,intermicrovillar adhesion,and cell junctions. Inhibition of host cholesterol and isoprenoid biosynthesis with Atorvastatin resulted in a reduction in parasite load only at higher doses,indicating that de novo synthesis may support,but is not required for,parasite replication. These novel models therefore offer tractable tools for investigating how interactions between T. gondii and the host intestinal epithelium influence the course of infection. View Publication

Introduction: Pathogenic variants in canonical transforming growth factor β (TGFβ) signaling genes predispose patients to thoracic aortic aneurysm and dissection (TAAD),predominantly in aortic root. Although TAAD pathogenesis associated with TGFβ receptor defects is well characterized,distinct and redundant mechanisms of TGFβ isoforms in TAAD incidence and severity remain elusive. Objective: Here we examined the biological role of TGFB2 in smooth muscle cell (SMC) differentiation and investigated how TGFB2 defects can lead to regional TAAD manifestations. Methods: To characterize the role of TGFB2 in SMC differentiation and function,we employed human-induced pluripotent stem cell (hiPSC)-derived SMC differentiation,CRISPR/Cas9 gene editing,three-dimensional SMC constructs,and human aortic tissue samples. Results: Despite the similar effects of different TGFβ isoforms on hiPSC-derived SMC differentiation,siRNA experiments revealed that TGFB2 distinctively displays TGFBR3 dependence for signal transduction,an understudied TGFβ receptor in TAAD. Molecular evaluation of different thoracic aorta regions suggested TGFB2 and TGFBR3 enrichment in the aortic root tunica media. TGFB2 haploinsufficiency (TGFB2KO/+) and TGFB2 neutralization impaired the differentiation of second heart field-derived SMCs. TGFBR3KO/KO prevented the molecular rescue of TGFB2KO/+ by TGFB2 supplementation indicating the involvement of TGFBR3 in TGFB2-mediated SMC differentiation. Lastly,a missense TGFB2 variant (TGFB2G276R/+) caused mechanical defects in SMC tissue ring constructs that were rescued by TGFB2 supplementation or genetic correction. Conclusion: Our data suggests the distinct regulation and action of TGFB2 in SMCs populating the aortic root,while redundant activities of TGFβ isoforms provide implications about the milder TAAD aggressiveness of pathogenic TGFB2 variants. View Publication

Idorn et al. characterized a mouse strain harboring a mutation identified in an HSE patient. Defective IFN-driven antiviral responses led to hyperactivation of inflammatory responses,which contributed to disease development. The study identifies immunopathology as an important contributor to HSE pathogenesis. View Publication

The COVID-19 pandemic has created a global health crisis,with challenges arising from the ongoing evolution of the SARS-CoV-2 virus,the emergence of new strains,and the long-term effects of COVID-19. Aiming to overcome the development of viral resistance,our study here focused on developing broad-spectrum pan-coronavirus antiviral therapies by targeting host protein quality control mechanisms essential for viral replication. Screening an in-house compound library led to the discovery of three candidate compounds targeting cellular proteostasis. The three compounds are (1) the nucleotide analog cordycepin,(2) a benzothiozole analog,and (3) an acyldepsipeptide analog initially developed as part of a campaign to target the mitochondrial ClpP protease. These compounds demonstrated dose-dependent efficacy against multiple coronaviruses,including SARS-CoV-2,effectively inhibiting viral replication in vitro as well as in lung organoids. Notably,the compounds also showed efficacy against SARS-CoV-2 delta and omicron strains. As part of this work,we developed a BSL2-level cell-integrated SARS-CoV-2 replicon,which could serve as a valuable tool for high-throughput screening and studying intracellular viral replication. Our study should aid in the advancement of antiviral drug development efforts. Subject terms: High-throughput screening,Small molecules View Publication

Robust in vitro lung models are required for risk assessment to measure key events leading to respiratory diseases. Primary normal human bronchial epithelial cells (NHBE) represent a good lung model but obtaining well-differentiated 3D cultures can be challenging. Here,we evaluated the ability to expand primary NHBE cells in different culture conditions while maintaining their 3D culture characteristics such as ciliated and goblet cells,and ion channel function. Differentiated cultures were optimally obtained with PneumaCult-Ex Plus (expansion medium)/PneumaCult-ALI (differentiation medium). Primary cells passaged up to four times maintained airway epithelial characteristics as evidenced by ciliated pseudostratified columnar epithelium with goblet cells,trans-epithelial electrical resistance (TEER) ({\textgreater}400 Ohms.cm2),and cystic fibrosis transmembrane conductance regulator-mediated short-circuit currents ({\textgreater}3 µA/cm2). No change in ciliary beat frequency (CBF) or airway surface liquid (ASL) meniscus length was observed up to passage six. For the first time,this study demonstrates that CFTR ion channel function and normal epithelial phenotypic characteristics are maintained in passaged primary NHBE cells. Furthermore,this study highlights the criticality of evaluating expansion and differentiation conditions for achieving optimal phenotypic and functional endpoints (CBF,ASL,ion channel function,presence of differentiated cells,TEER) when developing in vitro lung models. View Publication

We evaluate the effect of most FDA-approved drugs (>7,000 conditions) on double-strand DNA break repair pathways by analyzing mutational outcomes in human induced pluripotent stem cells. We identify drugs that can be repurposed as inhibitors and enhancers of repair outcomes attributed to non-homologous and microhomology-mediated end joining (NHEJ,MMEJ),and homology-directed repair (HDR). We also identify functions of the proteins estrogen receptor 2 (ESR2) and aldehyde oxidase 1 (AOX1),affecting several key DNA repair proteins,such as ATM and 53BP1. Silencing of ESR2 can have a synergistic effect on increasing HDR when combined with NHEJ inhibition (mean 4.6-fold increase). We further identify drugs that induce synthetic lethality when NHEJ or HDR is blocked and may therefore be candidates for precision medicine. We anticipate that the ability to modulate the DNA repair outcomes with clinically safe drugs will help disease modeling,gene therapy,chimeric antigen receptor immunotherapy,and cancer treatment. DNA repair pathways shape CRISPR editing outcomes. Here,authors identified FDA approved drugs that can be repurposed as repair modulators or to induce synthetic lethality,and uncovered new roles for ESR2 and AOX1 in DNA repair,enhancing editing and offering potential therapeutic applications. View Publication

5-Azacytidine was first synthesized almost 40 years ago. It was demonstrated to have a wide range of anti-metabolic activities when tested against cultured cancer cells and to be an effective chemotherapeutic agent for acute myelogenous leukemia. However,because of 5-azacytidine's general toxicity,other nucleoside analogs were favored as therapeutics. The finding that 5-azacytidine was incorporated into DNA and that,when present in DNA,it inhibited DNA methylation,led to widespread use of 5-azacytidine and 5-aza-2'-deoxycytidine (Decitabine) to demonstrate the correlation between loss of methylation in specific gene regions and activation of the associated genes. There is now a revived interest in the use of Decitabine as a therapeutic agent for cancers in which epigenetic silencing of critical regulatory genes has occurred. Here,the current status of our understanding of the mechanism(s) by which 5-azacytosine residues in DNA inhibit DNA methylation is reviewed with an emphasis on the interactions of these residues with bacterial and mammalian DNA (cytosine-C5) methyltransferases. The implications of these mechanistic studies for development of less toxic inhibitors of DNA methylation are discussed. View Publication