产品说明

The ionophorous properties of a new antibiotic,ionomycin,have been studied. It was found that the antibiotic is capable of extracting calcium ion from the bulk of an aqueous phase into an organic phase. The antibiotic also acts as a mobile ion carrier to transport the cation across a solvent barrier. The divalent cation selectivity order for ionomycin as determined by ion competition experiments was found to be: Ca greater than Mg greater than Sr = Ba,where the binding of strontium and barium by the antibiotic is insignificant. The antibiotic also binds La3+ to some extent,but its complexation with monovalent alkali metal ions is negligible. Measurement of the binding of ionomycin with Ca2+ indicates that ionomycin complexes and transports calcium ion in a one to one stoichiometry. View Publication

BACKGROUND The robust generation of human hematopoietic progenitor cells from induced or embryonic pluripotent stem cells would be beneficial for multiple areas of research,including mechanistic studies of hematopoiesis,the development of cellular therapies for autoimmune diseases,induced transplant tolerance,anticancer immunotherapies,disease modeling,and drug/toxicity screening. Over the past years,significant progress has been made in identifying effective protocols for hematopoietic differentiation from pluripotent stem cells and understanding stages of mesodermal,endothelial,and hematopoietic specification. Thus,it has been shown that variations in cytokine and inhibitory molecule treatments in the first few days of hematopoietic differentiation define primitive versus definitive potential of produced hematopoietic progenitor cells. The majority of current feeder-free,defined systems for hematopoietic induction from pluripotent stem cells include prolonged incubations with various cytokines that make the differentiation process complex and time consuming. We established that the application of Wnt agonist CHIR99021 efficiently promotes differentiation of human pluripotent stem cells in the absence of any hematopoietic cytokines to the stage of hemogenic endothelium capable of definitive hematopoiesis. METHODS The hemogenic endothelium differentiation was accomplished in an adherent,serum-free culture system by applying CHIR99021. Hemogenic endothelium progenitor cells were isolated on day 5 of differentiation and evaluated for their endothelial,myeloid,and lymphoid potential. RESULTS Monolayer induction based on GSK3 inhibition,described here,yielded a large number of CD31(+)CD34(+) hemogenic endothelium cells. When isolated and propagated in adherent conditions,these progenitors gave rise to mature endothelium. When further cocultured with OP9 mouse stromal cells,these progenitors gave rise to various cells of myeloid lineages as well as natural killer lymphoid,T-lymphoid,and B-lymphoid cells. CONCLUSION The results of this study substantiate a method that significantly reduces the complexity of current protocols for hematopoietic induction,offers a defined system to study the factors that affect the early stages of hematopoiesis,and provides a new route of lymphoid and myeloid cell derivation from human pluripotent stem cells,thus enhancing their use in translational medicine. View Publication

Neural stem cells (NSCs) have the ability to self-renew and to differentiate into various cell types of the central nervous system. This potential can be recapitulated by human induced pluripotent stem cells (hiPSCs) in vitro. The differentiation capacity of hiPSCs is characterized by several stages with distinct morphologies and the expression of various marker molecules. We used the monoclonal antibodies (mAbs) 487(LeX),5750(LeX) and 473HD to analyze the expression pattern of particular carbohydrate motifs as potential markers at six differentiation stages of hiPSCs. Mouse ESCs were used as a comparison. At the pluripotent stage,487(LeX)-,5750(LeX)- and 473HD-related glycans were differently expressed. Later,cells of the three germ layers in embryoid bodies (hEBs) and,even after neuralization of hEBs,subpopulations of cells were labeled with these surface antibodies. At the human rosette-stage of NSCs (hR-NSC),LeX- and 473HD-related epitopes showed antibody-specific expression patterns. We also found evidence that these surface antibodies could be used to distinguish the hR-NSCs from the hSR-NSCs stages. Characterization of hNSCs(FGF-2/EGF) derived from hSR-NSCs revealed that both LeX antibodies and the 473HD antibody labeled subpopulations of hNSCs(FGF-2/EGF). Finally,we identified potential LeX carrier molecules that were spatiotemporally regulated in early and late stages of differentiation. Our study provides new insights into the regulation of glycoconjugates during early human stem cell development. The mAbs 487(LeX),5750(LeX) and 473HD are promising tools for identifying distinct stages during neural differentiation. View Publication

Anorexia nervosa (AN) is a complex and multifactorial disorder occurring predominantly in women. Despite having the highest mortality among psychiatric conditions,it still lacks robust and effective treatment. Disorders such as AN are most likely syndromes with multiple genetic contributions,however,genome-wide studies have been underpowered to reveal associations with this uncommon illness. Here,we generated induced pluripotent stem cells (iPSCs) from adolescent females with AN and unaffected controls. These iPSCs were differentiated into neural cultures and subjected to extensive transcriptome analysis. Within a small cohort of patients who presented for treatment,we identified a novel gene that appears to contribute to AN pathophysiology,TACR1 (tachykinin 1 receptor). The participation of tachykinins in a variety of biological processes and their interactions with other neurotransmitters suggest novel mechanisms for how a disrupted tachykinin system might contribute to AN symptoms. Although TACR1 has been associated with psychiatric conditions,especially anxiety disorders,we believe this report is its first association with AN. Moreover,our human iPSC approach is a proof-of-concept that AN can be modeled in vitro with a full human genetic complement,and represents a new tool for understanding the elusive molecular and cellular mechanisms underlying the disease. View Publication

GABAergic interneurons are essential for neural circuit function,and their loss or dysfunction is implicated in human neuropsychiatric disease. In vitro methods for interneuron generation hold promise for studying human cellular and functional properties and,ultimately,for therapeutic cell replacement. Here we describe a protocol for generating cortical interneurons from hESCs and analyze the properties and maturation time course of cell types using single-cell RNA-seq. We find that the cell types produced mimic in vivo temporal patterns of neuron and glial production,with immature progenitors and neurons observed early and mature cortical neurons and glial cell types produced late. By comparing the transcriptomes of immature interneurons to those of more mature neurons,we identified genes important for human interneuron differentiation. Many of these genes were previously implicated in neurodevelopmental and neuropsychiatric disorders. View Publication

Embryonic stem cells (ESC) are derived from the inner cell mass (ICM) of preimplantation blastocysts. To date,it has been challenging to establish pluripotent ESC lines for domestic animals,which could be important for biotechnological applications,such as genetic engineering and SCNT,and biomedical research. The aim of this work was to derive and characterise bovine embryonic stem-like cells (bESC) from in vitro-produced bovine blastocysts. Embryos were produced by in vitro fertilization of in vitro-matured oocytes aspirated from abattoir ovaries and cultured in groups of 25 in 50-μL drops of KSOM (Evolve,Zenith Biotech) with 4mgmL(-1) BSA for 7 days until they reached the blastocyst stage (Ross et al.,2009 Reproduction 137,427-437). At that point,the zona pellucida (ZP) was removed using 1mgmL(-1) Pronase (Sigma,St. Louis,MO),and ZP-free blastocysts were washed 6 times in SOF-HEPES. Three derivation approaches were tested: ZP-free whole blastocysts,mechanically isolated ICM,and immunosurgery-derived ICM. In each case,individual blastocysts/ICM were placed in 1 well of a 12-well dish seeded with a monolayer of mouse embryo fibroblasts (MEF) and cultured in mTeSR1 basal medium (without growth factors) supplemented with 20ngmL(-1) FGF2 and 2.5μM IWR1 (CTFR) (Wu et al. 2015 Nature 521,316-321). After 48h,blastocysts/ICM that failed to adhere were physically pressed against the bottom of the culture dish with a 22-gauge needle under a stereoscope to aid attachment. Thereafter,the media was changed daily. Outgrowths (after 6-7 days in culture) were dissociated and passaged using TrypLE and re-seeded in the presence of ROCK inhibitor (Y-27632,10μM) onto newly prepared wells containing MEF. Established bESC lines were cultured on MEF and passaged every 4 to 5 days at a 1:10 split ratio. The bESC lines were characterised by immunofluorescence (IF),RNA-seq,and teratoma formation. The efficiency of cell line derivation (evaluated at passage 3) was similar for the 3 approaches: whole blastocysts (9/16,56.3%),mechanical ICM isolation (7/12,58.3%),and immunosurgical ICM isolation (7/16,43.8%). The bESC were passaged and cultured long-term (more than 15 passages) and were subjected to several rounds of freezing and thawing while retaining their morphology and characteristics. IF analysis showed that long-term cultured bESC expressed the markers SOX2 and OCT4 (pluripotency),but did not express CDX2 (trophectoderm) or GATA6 (primitive endoderm). RNAseq analysis of 2 bESC lines showed that ICM markers (POU5F1,NANOG,SOX2,LIN28B,DNAMT3B,UTF1,SALL4) were expressed (RPKMtextgreater0.4),while trophectoderm markers (CDX2,GATA2,GATA3,FGF4,TFAP2A) and primitive endoderm markers (GATA6,HNF4A) were not expressed (RPKMtextless0.4). Finally,bESC lines (n=2) were able to form teratomas in immunodeficient mice. The teratomas contained tissues representative of the 3 germ lineages and expressed lineage-specific markers (ectoderm: TUJ1,endoderm: FOXA2,and mesoderm: ASM). In conclusion,the culture condition used in this work (CTFR) enables robust derivation and long-term in vitro propagation of pluripotent bESC. View Publication

A self-organizing organoid model provides a new approach to study the mechanism of human liver organogenesis. Previous animal models documented that simultaneous paracrine signaling and cell-to-cell surface contact regulate hepatocyte differentiation. To dissect the relative contributions of the paracrine effects,we first established a liver organoid using human induced pluripotent stem cells (iPSCs),mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as previously reported. Time-lapse imaging showed that hepatic-specified endoderm iPSCs (HE-iPSCs) self-assembled into three-dimensional organoids,resulting in hepatic gene induction. Progressive differentiation was demonstrated by hepatic protein production after in vivo organoid transplantation. To assess the paracrine contributions,we employed a Transwell system in which HE-iPSCs were separately co-cultured with MSCs and/or HUVECs. Although the three-dimensional structure did not form,their soluble factors induced a hepatocyte-like phenotype in HE-iPSCs,resulting in the expression of bile salt export pump. In conclusion,the mesoderm-derived paracrine signals promote hepatocyte maturation in liver organoids,but organoid self-organization requires cell-to-cell surface contact. Our in vitro model demonstrates a novel approach to identify developmental paracrine signals regulating the differentiation of human hepatocytes. View Publication

Generation of midbrain dopaminergic (mDA) neurons from human pluripotent stem cells provides a platform for inquiry into basic and translational studies of Parkinson's disease (PD). However,heterogeneity in differentiation in vitro makes it difficult to identify mDA neurons in culture or in vivo following transplantation. Here,we report the generation of a human embryonic stem cell (hESC) line with a tyrosine hydroxylase (TH)-RFP (red fluorescent protein) reporter. We validated that RFP faithfully mimicked TH expression during differentiation. Use of this TH-RFP reporter cell line enabled purification of mDA-like neurons from heterogeneous cultures with subsequent characterization of neuron transcriptional and epigenetic programs (global binding profiles of H3K27ac,H3K4me1,and 5-hydroxymethylcytosine [5hmC]) at four different stages of development. We anticipate that the tools and data described here will contribute to the development of mDA neurons for applications in disease modeling and/or drug screening and cell replacement therapies for PD. View Publication

Spinal muscular atrophy (SMA),an autosomal recessive neuromuscular disease,is the leading monogenic cause of infant mortality. Homozygous loss of the gene survival of motor neuron 1 (SMN1) causes the selective degeneration of lower motor neurons and subsequent atrophy of proximal skeletal muscles. The SMN1 protein product,survival of motor neuron (SMN),is ubiquitously expressed and is a key factor in the assembly of the core splicing machinery. The molecular mechanisms by which disruption of the broad functions of SMN leads to neurodegeneration remain unclear. We used an antisense oligonucleotide (ASO)-based inducible mouse model of SMA to investigate the SMN-specific transcriptome changes associated with neurodegeneration. We found evidence of widespread intron retention,particularly of minor U12 introns,in the spinal cord of mice 30 d after SMA induction,which was then rescued by a therapeutic ASO. Intron retention was concomitant with a strong induction of the p53 pathway and DNA damage response,manifesting as γ-H2A.X positivity in neurons of the spinal cord and brain. Widespread intron retention and markers of the DNA damage response were also observed with SMN depletion in human SH-SY5Y neuroblastoma cells and human induced pluripotent stem cell-derived motor neurons. We also found that retained introns,high in GC content,served as substrates for the formation of transcriptional R-loops. We propose that defects in intron removal in SMA promote DNA damage in part through the formation of RNA:DNA hybrid structures,leading to motor neuron death. View Publication

Activation of thermogenic beige adipocytes has recently emerged as a promising therapeutic target in obesity and diabetes. Relevant human models for beige adipocyte differentiation are essential to implement such therapeutic strategies. We report a straightforward and efficient protocol to generate functional human beige adipocytes from human induced pluripotent stem cells (hiPSCs). Without overexpression of exogenous adipogenic genes,our method recapitulates an adipogenic developmental pathway through successive mesodermal and adipogenic progenitor stages. hiPSC-derived adipocytes are insulin sensitive and display beige-specific markers and functional properties,including upregulation of thermogenic genes,increased mitochondrial content,and increased oxygen consumption upon activation with cAMP analogs. Engraftment of hiPSC-derived adipocytes in mice produces well-organized and vascularized adipose tissue,capable of β-adrenergic-responsive glucose uptake. Our model of human beige adipocyte development provides a new and scalable tool for disease modeling and therapeutic screening. View Publication

The pig is the large animal model of choice for study of nerve regeneration and wound repair. Availability of porcine sensory neural cells would conceptually allow for analogous cell-based peripheral nerve regeneration in porcine injuries of similar severity and size to those found in humans. After recently reporting that porcine (or pig) induced pluripotent stem cells (piPSCs) differentiate into neural rosette (NR) structures similar to human NRs,here we demonstrate that pig NR cells could differentiate into neural crest cells and other peripheral nervous system-relevant cell types. Treatment with either bone morphogenetic protein 4 or fetal bovine serum led to differentiation into BRN3A-positive sensory cells and increased expression of sensory neuron TRK receptor gene family: TRKA,TRKB,and TRKC. Porcine sensory neural cells would allow determination of parallels between human and porcine cells in response to noxious stimuli,analgesics,and reparative mechanisms. In vitro differentiation of pig sensory neurons provides a novel model system for neural cell subtype specification and would provide a novel platform for the study of regenerative therapeutics by elucidating the requirements for innervation following injury and axonal survival. View Publication

Ion channels and transporters have increasingly recognized roles in cancer progression through the regulation of cell proliferation,migration,and death. Glioblastoma stem-like cells (GSCs) are a source of tumor formation and recurrence in glioblastoma multiforme,a highly aggressive brain cancer,suggesting that ion channel expression may be perturbed in this population. However,little is known about the expression and functional relevance of ion channels that may contribute to GSC malignancy. Using RNA sequencing,we assessed the enrichment of ion channels in GSC isolates and non-tumor neural cell types. We identified a unique set of GSC-enriched ion channels using differential expression analysis that is also associated with distinct gene mutation signatures. In support of potential clinical relevance,expression of selected GSC-enriched ion channels evaluated in human glioblastoma databases of The Cancer Genome Atlas and Ivy Glioblastoma Atlas Project correlated with patient survival times. Finally,genetic knockdown as well as pharmacological inhibition of individual or classes of GSC-enriched ion channels constrained growth of GSCs compared to normal neural stem cells. This first-in-kind global examination characterizes ion channels enriched in GSCs and explores their potential clinical relevance to glioblastoma molecular subtypes,gene mutations,survival outcomes,regional tumor expression,and experimental responses to loss-of-function. Together,the data support the potential biological and therapeutic impact of ion channels on GSC malignancy and provide strong rationale for further examination of their mechanistic and therapeutic importance. View Publication