技术资料

Current long term cryopreservation of cell stocks routinely requires the use of liquid nitrogen (LN2),because commonly used cryopreservation media containing cell membrane permeating cryoprotectants are thermally unstable when frozen at higher storage temperatures,e.g. -80 °C. This instability leads to ice recrystallization,causing progressive loss of cell viability over time under the storage conditions provided by most laboratory deep freezers. The dependency on LN2 for cell storage significantly increases operational expense and raises issues related to impaired working efficiency and safety. Here we demonstrate that addition of Ficoll 70 to cryoprotectant solutions significantly improves system thermal stability at the working temperature (˜-80 °C) of laboratory deep freezers. Moreover,a medium comprised of Ficoll 70 and dimethyl sulfoxide (DMSO) in presence or absence of fetal bovine serum (FBS) can provide reliable cryopreservation of various kinds of human and porcine pluripotent stem cells at -80 °C for periods that extend up to at least one year,with the post-thaw viability,plating efficiency,and full retention of pluripotent phenotype comparable to that achieved with LN2 storage. These results illustrate the practicability of a promising long-term cryopreservation method that completely eliminates the need for LN2. View Publication

Wnt signaling plays essential roles in both embryonic pattern formation and postembryonic tissue homoestasis. High levels of Wnt activity repress foregut identity and facilitate hindgut fate through forming a gradient of Wnt signaling activity along the anterior-posterior axis. Here,we examined the mechanisms of Wnt signaling in hindgut development by differentiating human embryonic stem cells (hESCs) into the hindgut progenitors. We observed severe morphological changes when Wnt signaling was blocked by using Wnt antagonist Dkk1. We performed deep-transcriptome sequencing (RNA-seq) and identified 240 Wnt-activated genes and 2023 Wnt-repressed genes,respectively. Clusters of Wnt targets showed enrichment in specific biological functions,such as gastrointestinal or skeletal development" in the Wnt-activated targets and "neural or immune system development" in the Wnt-repressed targets. Moreover� View Publication

Redirecting T cells to attack cancer using engineered chimeric receptors provides powerful new therapeutic capabilities. However,the effectiveness of therapeutic T cells is constrained by the endogenous T cell response: certain facets of natural response programs can be toxic,whereas other responses,such as the ability to overcome tumor immunosuppression,are absent. Thus,the efficacy and safety of therapeutic cells could be improved if we could custom sculpt immune cell responses. Synthetic Notch (synNotch) receptors induce transcriptional activation in response to recognition of user-specified antigens. We show that synNotch receptors can be used to sculpt custom response programs in primary T cells: they can drive a la carte cytokine secretion profiles,biased T cell differentiation,and local delivery of non-native therapeutic payloads,such as antibodies,in response to antigen. SynNotch T cells can thus be used as a general platform to recognize and remodel local microenvironments associated with diverse diseases. View Publication

Adverse effect of alcohol on neural function has been well documented. Especially,the teratogenic effect of alcohol on neurodevelopment during embryogenesis has been demonstrated in various models,which could be a pathologic basis for fetal alcohol spectrum disorders (FASDs). While the developmental defects from alcohol abuse during gestation have been described,the specific mechanisms by which alcohol mediates these injuries have yet to be determined. Recent studies have shown that alcohol has significant effect on molecular and cellular regulatory mechanisms in embryonic stem cell (ESC) differentiation including genes involved in neural development. To test our hypothesis that alcohol induces molecular alterations during neural differentiation we have derived neural precursor cells from pluripotent human ESCs in the presence or absence of ethanol treatment. Genome-wide transcriptomic profiling identified molecular alterations induced by ethanol exposure during neural differentiation of hESCs into neural rosettes and neural precursor cell populations. The Database for Annotation,Visualization and Integrated Discovery (DAVID) functional analysis on significantly altered genes showed potential ethanol's effect on JAK-STAT signaling pathway,neuroactive ligand-receptor interaction,Toll-like receptor (TLR) signaling pathway,cytokine-cytokine receptor interaction and regulation of autophagy. We have further quantitatively verified ethanol-induced alterations of selected candidate genes. Among verified genes we further examined the expression of P2RX3,which is associated with nociception,a peripheral pain response. We found ethanol significantly reduced the level of P2RX3 in undifferentiated hESCs,but induced the level of P2RX3 mRNA and protein in hESC-derived NPCs. Our result suggests ethanol-induced dysregulation of P2RX3 along with alterations in molecules involved in neural activity such as neuroactive ligand-receptor interaction may be a molecular event associated with alcohol-related peripheral neuropathy of an enhanced nociceptive response. View Publication

Human pluripotent stem cell (hPSC) derived tissues often remain developmentally immature in vitro,and become more adult-like in their structure,cellular diversity and function following transplantation into immunocompromised mice. Previously we have demonstrated that hPSC-derived human lung organoids (HLOs) resembled human fetal lung tissue in vitro (Dye et al.,2015). Here we show that HLOs required a bioartificial microporous poly(lactide-co-glycolide) (PLG) scaffold niche for successful engraftment,long-term survival,and maturation of lung epithelium in vivo. Analysis of scaffold-grown transplanted tissue showed airway-like tissue with enhanced epithelial structure and organization compared to HLOs grown in vitro. By further comparing in vitro and in vivo grown HLOs with fetal and adult human lung tissue,we found that in vivo transplanted HLOs had improved cellular differentiation of secretory lineages that is reflective of differences between fetal and adult tissue,resulting in airway-like structures that were remarkably similar to the native adult human lung. View Publication

Human embryonic stem cells (hESCs) is a potential unlimited ex vivo source of ventricular (V) cardiomyocytes (CMs),but hESC-VCMs and their engineered tissues display immature traits. In adult VCMs,sarcolemmal (sarc) and mitochondrial (mito) ATP-sensitive potassium (KATP) channels play crucial roles in excitability and cardioprotection. In this study,we aim to investigate the biological roles and use of sarcKATP and mitoKATP in hESC-VCM. We showed that SarcIK,ATP in single hESC-VCMs was dormant under baseline conditions,but became markedly activated by cyanide (CN) or the known opener P1075 with a current density that was ˜8-fold smaller than adult; These effects were reversible upon washout or the addition of GLI or HMR1098. Interestingly,sarcIK,ATP displayed a ˜3-fold increase after treatment with hypoxia (5% O2). MitoIK,ATP was absent in hESC-VCMs. However,the thyroid hormone T3 up-regulated mitoIK,ATP,conferring diazoxide protective effect on T3-treated hESC-VCMs. When assessed using a multi-cellular engineered 3D ventricular cardiac micro-tissue (hvCMT) system,T3 substantially enhanced the developed tension by 3-folds. Diazoxide also attenuated the decrease in contractility induced by simulated ischemia (1% O2). We conclude that hypoxia and T3 enhance the functionality of hESC-VCMs and their engineered tissues by selectively acting on sarc and mitoIK,ATP. View Publication

Human neocortex expansion likely contributed to the remarkable cognitive abilities of humans. This expansion is thought to primarily reflect differences in proliferation versus differentiation of neural progenitors during cortical development. Here,we have searched for such differences by analysing cerebral organoids from human and chimpanzees using immunohistochemistry,live imaging,and single-cell transcriptomics. We find that the cytoarchitecture,cell type composition,and neurogenic gene expression programs of humans and chimpanzees are remarkably similar. Notably,however,live imaging of apical progenitor mitosis uncovered a lengthening of prometaphase-metaphase in humans compared to chimpanzees that is specific to proliferating progenitors and not observed in non-neural cells. Consistent with this,the small set of genes more highly expressed in human apical progenitors points to increased proliferative capacity,and the proportion of neurogenic basal progenitors is lower in humans. These subtle differences in cortical progenitors between humans and chimpanzees may have consequences for human neocortex evolution. View Publication

Regions of the normal arterial intima predisposed to atherosclerosis are sites of ongoing monocyte trafficking and also contain resident myeloid cells with features of dendritic cells. However,the pathophysiological roles of these cells are poorly understood. Here we found that intimal myeloid cells underwent reverse transendothelial migration (RTM) into the arterial circulation after systemic stimulation of pattern-recognition receptors (PRRs). This process was dependent on expression of the chemokine receptor CCR7 and its ligand CCL19 by intimal myeloid cells. In mice infected with the intracellular pathogen Chlamydia muridarum,blood monocytes disseminated infection to the intima. Subsequent CCL19-CCR7-dependent RTM was critical for the clearance of intimal C. muridarum. This process was inhibited by hypercholesterolemia. Thus,RTM protects the normal arterial intima,and compromised RTM during atherogenesis might contribute to the intracellular retention of pathogens in atherosclerotic lesions. View Publication

While a third of the world carries the burden of tuberculosis,disease control has been hindered by a lack of tools,including a rapid,point-of-care diagnostic and a protective vaccine. In many infectious diseases,antibodies (Abs) are powerful biomarkers and important immune mediators. However,in Mycobacterium tuberculosis (Mtb) infection,a discriminatory or protective role for humoral immunity remains unclear. Using an unbiased antibody profiling approach,we show that individuals with latent tuberculosis infection (Ltb) and active tuberculosis disease (Atb) have distinct Mtb-specific humoral responses,such that Ltb infection is associated with unique Ab Fc functional profiles,selective binding to FcγRIII,and distinct Ab glycosylation patterns. Moreover,compared to Abs from Atb,Abs from Ltb drove enhanced phagolysosomal maturation,inflammasome activation,and,most importantly,macrophage killing of intracellular Mtb. Combined,these data point to a potential role for Fc-mediated Ab effector functions,tuned via differential glycosylation,in Mtb control. View Publication

We report a method of high-speed phase contrast and bright field microscopy which permits large cell culture vessels to be scanned at much higher speed (up to 30 times faster) than when conventional methods are used without compromising image quality. The object under investigation moves continuously and is captured using a flash illumination which creates an exposure time short enough to prevent motion blur. During the scan the object always stays in focus due to a novel hardware-autofocus system. View Publication

Mitochondria are critical to neurogenesis,but the mechanisms of mitochondria in neurogenesis have not been well explored. We fully characterized mitochondrial alterations and function in relation to the development of human induced pluripotent stem cell (hiPSC)-derived dopaminergic (DA) neurons. Following directed differentiation of hiPSCs to DA neurons,mitochondria in these neurons exhibit pronounced changes during differentiation,including mature neurophysiology characterization and functional synaptic network formation. Inhibition of mitochondrial respiratory chains via application of complex IV inhibitor KCN (potassium cyanide) or complex I inhibitor rotenone restricted neurogenesis of DA neurons. These results demonstrated the direct importance of mitochondrial development and bioenergetics in DA neuronal differentiation. Our study also provides a neurophysiologic model of mitochondrial involvement in neurogenesis,which will enhance our understanding of the role of mitochondrial dysfunctions in neurodegenerative diseases. View Publication

T cell activation in response to Ag is largely regulated by protein posttranslational modifications. Although phosphorylation has been extensively characterized in T cells,much less is known about the glycosylation of serine/threonine residues by O-linked N-acetylglucosamine (O-GlcNAc). Given that O-GlcNAc appears to regulate cell signaling pathways and protein activity similarly to phosphorylation,we performed a comprehensive analysis of O-GlcNAc during T cell activation to address the functional importance of this modification and to identify the modified proteins. Activation of T cells through the TCR resulted in a global elevation of O-GlcNAc levels and in the absence of O-GlcNAc,IL-2 production and proliferation were compromised. T cell activation also led to changes in the relative expression of O-GlcNAc transferase (OGT) isoforms and accumulation of OGT at the immunological synapse of murine T cells. Using a glycoproteomics approach,we identified textgreater200 O-GlcNAc proteins in human T cells. Many of the identified proteins had a functional relationship to RNA metabolism,and consistent with a connection between O-GlcNAc and RNA,inhibition of OGT impaired nascent RNA synthesis upon T cell activation. Overall,our studies provide a global analysis of O-GlcNAc dynamics during T cell activation and the first characterization,to our knowledge,of the O-GlcNAc glycoproteome in human T cells. View Publication