技术资料

Retinoic acid (RA) exerts its pleiotropic effects on cell growth and differentiation through the activation of a family of transcription factors-the RA receptors (RARs). Three subtypes of these receptors exist,RAR alpha,RAR beta,and RAR gamma. The receptors are differentially expressed in different cell types and stages of development,suggesting that they may regulate different sets of genes. We have identified a synthetic retinoid with the characteristics of a selective RAR alpha antagonist. This antagonist counteracts RA effects on HL-60 cell differentiation and on B-lymphocyte polyclonal activation. Beyond its potential practical relevance,this and other specific antagonists will be useful to dissect the RAR system and to assign to one given receptor each of the many RA-regulated functions. View Publication

Blood-brain barrier (BBB) models are often used to investigate BBB function and screen brain-penetrating therapeutics,but it has been difficult to construct a human model that possesses an optimal BBB phenotype and is readily scalable. To address this challenge,we developed a human in vitro BBB model comprising brain microvascular endothelial cells (BMECs),pericytes,astrocytes and neurons derived from renewable cell sources. First,retinoic acid (RA) was used to substantially enhance BBB phenotypes in human pluripotent stem cell (hPSC)-derived BMECs,particularly through adherens junction,tight junction,and multidrug resistance protein regulation. RA-treated hPSC-derived BMECs were subsequently co-cultured with primary human brain pericytes and human astrocytes and neurons derived from human neural progenitor cells (NPCs) to yield a fully human BBB model that possessed significant tightness as measured by transendothelial electrical resistance (˜5,000 $\$(2)). Overall,this scalable human BBB model may enable a wide range of neuroscience studies. View Publication

Organogenesis of the trachea and lungs requires a complex series of mesoderm-endoderm interactions mediated by WNT,BMP,retinoic acid (RA),and hedgehog (Hh),but how these pathways interact in a gene regulatory network is less clear. Using Xenopus embryology,mouse genetics,and human ES cell cultures,we identified a conserved signaling cascade that initiates respiratory lineage specification. We show that RA has multiple roles; first RA pre-patterns the lateral plate mesoderm and then it promotes Hh ligand expression in the foregut endoderm. Hh subsequently signals back to the pre-patterned mesoderm to promote expression of the lung-inducing ligands Wnt2/2b and Bmp4. Finally,RA regulates the competence of the endoderm to activate the Nkx2-1+ respiratory program in response to these mesodermal WNT and BMP signals. These data provide insights into early lung development and a paradigm for how mesenchymal signals are coordinated with epithelial competence during organogenesis. View Publication

Enzymatic dissociation of human pluripotent stem cells (hPSCs) into single cells during routine passage leads to massive cell death. Although the Rho-associated protein kinase inhibitor,Y-27632 can enhance hPSC survival and proliferation at high seeding density,dissociated single cells undergo apoptosis at clonal density. This presents a major hurdle when deriving genetically modified hPSC lines since transfection and genome editing efficiencies are not satisfactory. As a result,colonies tend to contain heterogeneous mixtures of both modified and unmodified cells,making it difficult to isolate the desired clone buried within the colony. In this study,we report improved clonal expansion of hPSCs using a retinoic acid analogue,TTNPB. When combined with Y-27632,TTNPB synergistically increased hPSC cloning efficiency by more than 2 orders of magnitude (0.2% to 20%),whereas TTNPB itself increased more than double cell number expansion compared to Y-27632. Furthermore,TTNPB-treated cells showed two times higher aggregate formation and cell proliferation compared to Y-27632 in suspension culture. TTNPB-treated cells displayed a normal karyotype,pluripotency and were able to stochastically differentiate into all three germ layers both in vitro and in vivo. TTNBP acts,in part,by promoting cellular adhesion and self-renewal through the upregulation of Claudin 2 and HoxA1. By promoting clonal expansion,TTNPB provides a new approach for isolating and expanding pure hPSCs for future cell therapy applications. A retinoic acid analogue,TTNPB,improves clonal expansion in adherent and suspension culture of hPSCs by promoting cellular adhesion and self-renewal through the upregulation of Claudin 2 and HoxA1. View Publication

Air-liquid interface (ALI) culture of nasal epithelial cells is a valuable tool in the diagnosis and research of primary ciliary dyskinesia (PCD). Ex vivo samples often display secondary dyskinesia from cell damage during sampling,infection or inflammation confounding PCD diagnostic results. ALI culture enables regeneration of healthy cilia facilitating differentiation of primary from secondary ciliary dyskinesia. We describe a revised ALI culture method adopted from April 2018 across three collaborating PCD diagnostic sites,including current University Hospital Southampton COVID-19 risk mitigation measures,and present results. Two hundred and forty nasal epithelial cell samples were seeded for ALI culture and 199 (82.9{\%}) were ciliated. Fifty-four of 83 (63.9{\%}) ex vivo samples which were originally equivocal or insufficient provided diagnostic information following in vitro culture. Surplus basal epithelial cells from 181 nasal brushing samples were frozen in liquid nitrogen; 39 samples were ALI-cultured after cryostorage and all ciliated. The ciliary beat patterns of ex vivo samples (by high-speed video microscopy) were recapitulated,scanning electron microscopy demonstrated excellent ciliation,and cilia could be immuno-fluorescently labelled (anti-alpha-tubulin and anti-RSPH4a) in representative cases that were ALI-cultured after cryostorage. In summary,our ALI culture protocol provides high ciliation rates across three centres,minimising patient recall for repeat brushing biopsies and improving diagnostic certainty. Cryostorage of surplus diagnostic samples was successful,facilitating PCD research. View Publication

Fasudil,a Rho-kinase inhibitor,may improve insulin signaling. However,its long-term effect on metabolic abnormalities and its preventive effect on diabetic nephropathy are still unknown. We assessed these effects of fasudil in insulin-resistant diabetic rats,comparing them with those of an angiotensin II receptor blocker,olmesartan. Male Otsuka Long-Evans Tokushima fatty (OLETF) and Long-Evans Tokushima Otsuka,non-diabetic control,rats at 15 weeks of age were used. OLETF rats were randomized to receive a low or a high dose of fasudil or olmesartan for 25 weeks. To examine the therapeutic effects after the development of diabetes,OLETF rats at 30 weeks of age were given fasudil for 10 weeks. Administration of high-dose fasudil completely suppressed the development of diabetes,obesity,and dyslipidemia and increased serum adiponectin levels in OLETF rats. High-dose olmesartan also decreased hemoglobin A1c and increased serum adiponectin. There was a significant correlation between hemoglobin A1c and serum adiponectin or free fatty acid levels. The treatment with high-dose fasudil ameliorated proteinuria,glomerulosclerosis,renal interstitial fibrosis,and macrophage infiltration in OLETF rats. Olmesartan,even at the low dose,suppressed renal complications. The treatment with fasudil after the development of diabetes improved the metabolic abnormalities in OLETF rats,but could not suppress the progression of nephropathy. We conclude that the long-term treatment with fasudil prevents the development of diabetes,at least in part,by improving adipocyte differentiation in insulin-resistant diabetic rats. Early use of fasudil may prevent diabetic nephropathy. View Publication

Neural crest (NC) cells contribute to the development of many complex tissues of all three germ layers during embryogenesis,and its abnormal development accounts for several congenital birth defects. Generating NC cells-including specific subpopulations such as cranial,cardiac,and trunk NC cells-from human pluripotent stem cells will provide a valuable model system to study human development and disease. Here,we describe a rapid and robust NC differentiation method called LSB-short" that is based on dual SMAD pathway inhibition. This protocol yields high percentages of NC cell populations from multiple human induced pluripotent stem and human embryonic stem cell lines in 8 days. The resulting cells can be propagated easily View Publication

Poor survival of human embryonic stem (hES) cells after cell dissociation is an obstacle to research,hindering manipulations such as subcloning. Here we show that application of a selective Rho-associated kinase (ROCK) inhibitor,Y-27632,to hES cells markedly diminishes dissociation-induced apoptosis,increases cloning efficiency (from approximately 1% to approximately 27%) and facilitates subcloning after gene transfer. Furthermore,dissociated hES cells treated with Y-27632 are protected from apoptosis even in serum-free suspension (SFEB) culture and form floating aggregates. We demonstrate that the protective ability of Y-27632 enables SFEB-cultured hES cells to survive and differentiate into Bf1(+) cortical and basal telencephalic progenitors,as do SFEB-cultured mouse ES cells. View Publication

Mesenteric lymph node (mLN) CD103 (alphaE integrin)(+) dendritic cells (DCs) induce regulatory T cells and gut tolerance. However,the function of intestinal CD103(-) DCs remains to be clarified. CD47 is the ligand of signal regulatory protein alpha (SIRPalpha) and promotes SIRPalpha(+) myeloid cell migration. We first show that mucosal CD103(-) DCs selectively express SIRPalpha and that their frequency was augmented in the lamina propria and mLNs of mice that developed Th17-biased colitis in response to trinitrobenzene sulfonic acid. In contrast,the percentage of SIRPalpha(+)CD103(-) DCs and Th17 responses were decreased in CD47-deficient (CD47 knockout [KO]) mice,which remained protected from colitis. We next demonstrate that transferring wild-type (WT),but not CD47 KO,SIRPalpha(+)CD103(-) DCs in CD47 KO mice elicited severe Th17-associated wasting disease. CD47 expression was required on the SIRPalpha(+)CD103(-) DCs for efficient trafficking to mLNs in vivo,whereas it was dispensable on both DCs and T cells for Th17 polarization in vitro. Finally,administration of a CD47-Fc molecule resulted in reduced SIRPalpha(+)CD103(-) DC-mediated Th17 responses and the protection of WT mice from colitis. We thus propose SIRPalpha(+)CD103(-) DCs as a pathogenic DC subset that drives Th17-biased responses and colitis,and the CD47-SIRPalpha axis as a potential therapeutic target for inflammatory bowel disease. View Publication

The repertoire of receptors that is expressed by NK cells is critical for their ability to kill virally infected or transformed cells. However,the molecular mechanisms that determine whether and when NK receptor genes are transcribed during hemopoiesis remain unclear. In this study,we show that hypomethylation of a CpG-rich region in the mouse NKG2A gene is associated with transcription of NKG2A in ex vivo NK cells and NK cell lines. This observation was extended to various developmental stages of NK cells sorted from bone marrow,in which we demonstrate that the CpGs are methylated in the NKG2A-negative stages (hemopoietic stem cells,NK progenitors,and NKG2A-negative NK cells),and hypomethylated specifically in the NKG2A-positive NK cells. Furthermore,we provide evidence that DNA methylation is important in maintaining the allele-specific expression of NKG2A. Finally,we show that acetylated histones are associated with the CpG-rich region in NKG2A positive,but not negative,cell lines,and that treatment with the histone deacetylase inhibitor trichostatin A alone is sufficient to induce NKG2A expression. Treatment with the methyltransferase inhibitor 5-azacytidine only is insufficient to induce transcription,but cotreatment with both drugs resulted in a significantly greater induction,suggesting a cooperative role for DNA methylation and histone acetylation status in regulating gene expression. These results enhance our understanding of the formation and maintenance of NK receptor repertoires in developing and mature NK cells. View Publication

We have tracked the fate of immature human B cells at a critical stage in their development when the mature B cell repertoire is shaped. We show that a major subset of bone marrow emigrant immature human B cells,the transitional 2 (T2) B cells,homes to gut-associated lymphoid tissue (GALT) and that most T2 B cells isolated from human GALT are activated. Activation in GALT is a previously unknown potential fate for immature human B cells. The process of maturation from immature transitional B cell through to mature naive B cell includes the removal of autoreactive cells from the developing repertoire,a process which is known to fail in systemic lupus erythematosus (SLE). We observe that immature B cells in SLE are poorly equipped to access the gut and that gut immune compartments are depleted in SLE. Thus,activation of immature B cells in GALT may function as a checkpoint that protects against autoimmunity. In healthy individuals,this pathway may be involved in generating the vast population of IgA plasma cells and also the enigmatic marginal zone B cell subset that is poorly understood in humans. View Publication

Natural killer (NK) cells have been originally defined by their naturally occurring" effector function. However View Publication