技术资料

The biological effects of low-dose ionizing radiation (LDIR) exposure in humans are not comprehensively understood,generating a high degree of controversy in published literature. The earliest stages of human development are known to be among the most sensitive to stress exposures,especially genotoxic stresses. However,the risks stemming from exposure to LDIR,particularly within the clinical diagnostic relevant dose range,have not been directly evaluated in human embryonic stem cells (hESCs). Here,we describe the dynamics of the whole genome transcriptional responses of different hESC lines to both LDIR and,as a reference,high-dose IR (HDIR). We found that even doses as low as 0.05 Gy could trigger statistically significant transient changes in a rather limited subset of genes in all hESCs lines examined. Gene expression signatures of hESCs exposed to IR appear to be highly dose-,time-,and cell line-dependent. We identified 50 genes constituting consensus gene expression signature as an early response to HDIR across all lines of hESC examined. We observed substantial differences in biological pathways affected by either LDIR or HDIR in hESCs,suggesting that the molecular mechanisms underpinning the responses of hESC may fundamentally differ depending on radiation doses. View Publication

PURPOSE To investigate the effects and mechanisms of fasudil hydrochloride (fasudil) on and in alkali burn-induced corneal neovascularization (CNV) in mice. METHODS To observe the effect of fasudil,mice with alkali-burned corneas were treated with either fasudil eye drops or phosphate-buffered saline (PBS) four times per day for 14 consecutive days. After injury,CNV and corneal epithelial defects were measured. The production of reactive oxygen species (ROS) and heme oxygenase-1(HO-1) was measured. The infiltration of polymorphonuclear neutrophils (PMNs) and the mRNA expressions of CNV-related genes were analyzed on day 14. RESULTS The incidence of CNV was significantly lower after treatment with 100 μM and 300 μM fasudil than with PBS,especially with 100 μM fasudil. Meanwhile,the incidences of corneal epithelial defects was lower (n=15,all ptextless0.01). After treatment with 100 μM fasudil,the intensity of DHE fluorescence was reduced in the corneal epithelium and stroma than with PBS treatment (n=5,all ptextless0.01),and the number of filtrated PMNs decreased. There were significant differences between the expressions of VEGF,TNF-a,MMP-8,and MMP-9 in the 100 μM fasudil group and the PBS group (n=8,all ptextless0.05). The production of HO-1 protein in the 100 μM fasudil group was 1.52±0.34 times more than in the PBS group (n=5 sample,ptextless0.05). CONCLUSIONS 100 μM fasudil eye drops administered four times daily can significantly inhibit alkali burn-induced CNV and promote the healing of corneal epithelial defects in mice. These effects are attributed to a decrease in inflammatory cell infiltration,reduction of ROS,and upregulation of HO-1 protein after fasudil treatment. View Publication

Reprogramming of patient cells to human induced pluripotent stem cells (hiPSC) has facilitated in vitro disease modeling studies aiming at deciphering the molecular and cellular mechanisms that contribute to disease pathogenesis and progression. To fully exploit the potential of hiPSC for biomedical applications,technologies that enable the standardized generation and expansion of hiPSC from large numbers of donors are required. Paralleled automated processes for the expansion of hiPSC could provide an opportunity to maximize the generation of hiPSC collections from patient cohorts while minimizing hands-on time and costs. In order to develop a simple method for the parallel expansion of human pluripotent stem cells (hPSC) we established a protocol for their cultivation as undifferentiated aggregates in a bench-top bioreactor system (BioLevitator™). We show that long-term expansion (10 passages) of hPSCs either in mTeSR or E8 medium preserved a normal karyotype,three-germ-layer differentiation potential and high expression of pluripotency-associated markers. The system enables the expansion from low inoculation densities (0.3 × 10(5) cells/mL) and provides a simplified,cost-efficient and time-saving method for the provision of hiPSC at midi-scale. Implementation of this protocol in cell production schemes has the potential to advance cell manufacturing in many areas of hiPSC-based medical research. View Publication

PURPOSE We conducted an open-label,single-arm Phase I/II clinical trial in metastatic CRPC (mCRPC) patients eligible for docetaxel combined with treatment with autologous mature dendritic cells (DCs) pulsed with killed LNCaP prostate cancer cells (DCVAC/PCa). The primary and secondary endpoints were safety and immune responses,respectively. Overall survival (OS),followed as a part of the safety evaluation,was compared to the predicted OS according to the Halabi and MSKCC nomograms. EXPERIMENTAL DESIGN Twenty-five patients with progressive mCRPC were enrolled. Treatment comprised of initial 7 days administration of metronomic cyclophosphamide 50 mg p.o. DCVAC/PCa treatment consisted of a median twelve doses of 1 × 107 dendritic cells per dose injected s.c. (Aldara creme was applied at the site of injection) during a one-year period. The initial 2 doses of DCVAC/PCa were administered at a 2-week interval,followed by the administration of docetaxel (75 mg/m2) and prednisone (5 mg twice daily) given every 3 weeks until toxicity or intolerance was observed. The DCVAC/PCa was then injected every 6 weeks up to the maximum number of doses manufactured from one leukapheresis. RESULTS No serious DCVAC/PCa-related adverse events have been reported. The median OS was 19 months,whereas the predicted median OS was 11.8 months with the Halabi nomogram and 13 months with the MSKCC nomogram. Kaplan-Meier analyses showed that patients had a lower risk of death compared with both MSKCC (Hazard Ratio 0.26,95% CI: 0.13-0.51) and Halabi (Hazard Ratio 0.33,95% CI: 0.17-0.63) predictions. We observed a significant decrease in Tregs in the peripheral blood. The long-term administration of DCVAC/PCa led to the induction and maintenance of PSA specific T cells. We did not identify any immunological parameter that significantly correlated with better OS. CONCLUSIONS In patients with mCRPC,the combined chemoimmunotherapy with DCVAC/PCa and docetaxel was safe and resulted in longer than expected survival. Concomitant chemotherapy did not preclude the induction of specific anti-tumor cytotoxic T cells. View Publication

Monomeric clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated 9 (Cas9) nucleases have been widely adopted for simple and robust targeted genome editing but also have the potential to induce high-frequency off-target mutations. In principle,two orthogonal strategies for reducing off-target cleavage,truncated guide RNAs (tru-gRNAs) and dimerization-dependent RNA-guided FokI-dCas9 nucleases (RFNs),could be combined as tru-RFNs to further improve genome editing specificity. Here we identify a robust tru-RFN architecture that shows high activity in human cancer cell lines and embryonic stem cells. Additionally,we demonstrate that tru-gRNAs reduce the undesirable mutagenic effects of monomeric FokI-dCas9. Tru-RFNs combine the advantages of two orthogonal strategies for improving the specificity of CRISPR-Cas nucleases and therefore provide a highly specific platform for performing genome editing. View Publication

Human embryonic stem cells (hESC) and induced pluripotent stem cells (hiPSC) assert a great future for the cardiovascular diseases,both to study them and to explore therapies. However,a comprehensive assessment of the viral vectors used to modify these cells is lacking. In this study,we aimed to compare the transduction efficiency of recombinant adeno-associated vectors (AAV),adenoviruses and lentiviral vectors in hESC,hiPSC,and the derived cardiomyocytes. In undifferentiated cells,adenoviral and lentiviral vectors were superior,whereas in differentiated cells AAV surpassed at least lentiviral vectors. We also tested four AAV serotypes,1,2,6,and 9,of which 2 and 6 were superior in their transduction efficiency. Interestingly,we observed that AAVs severely diminished the viability of undifferentiated cells,an effect mediated by induction of cell cycle arrest genes and apoptosis. Furthermore,we show that the transduction efficiency of the different viral vectors correlates with the abundance of their respective receptors. Finally,adenoviral delivery of the calcium-transporting ATPase SERCA2a to hESC and hiPSC-derived cardiomyocytes successfully resulted in faster calcium reuptake. In conclusion,adenoviral vectors prove to be efficient for both differentiated and undifferentiated lines,whereas lentiviral vectors are more applicable to undifferentiated cells and AAVs to differentiated cells. View Publication

Human pluripotent stem cells (hPSCs),such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs),provide a powerful model system for studies of cellular identity and early mammalian development,which hold great promise for regenerative medicine. It is necessary to develop a convenient method to discriminate hPSCs from other cells in clinics and basic research. Herein,a simple and reliable biosensor for stem cell detection was established. In this biosensor system,stage-specific embryonic antigen-3 (SSEA-3) and stage-specific embryonic antigen-4 (SSEA-4) were used to mark human pluripotent stem cells (hPSCs). Antibody specific for SSEA-3 was coated onto magnetic beads for hPSCs enrichment,and antibody specific for SSEA-4 was conjugated with carboxyl-modified tDNA sequence which was used as template for strand displacement amplification (SDA). The amplified single strand DNA (ssDNA) was detected with a lateral flow biosensor (LFB). This biosensor is capable of detecting a minimum of 19 human embryonic stem cells by a strip reader and 100 human embryonic stem cells by the naked eye within 80min. This approach has also shown excellent specificity to distinguish hPSCs from other types of cells,showing that it is promising for specific and handy detection of human pluripotent stem cells. View Publication

Human Embryonic Stem Cells (hESC) offer an important resource as a limitless supply of any differentiated cell type of the human body. Keratocytes,cells from the corneal stroma,may have the potential for restoration of vision in cell therapy and biomedical engineering applications,but these specialized cells are not readily expanded in vitro. Here we describe a two-part method to produce keratocytes from the H1 hESC cell line. The hESC cells,maintained and expanded in feeder-free culture medium are first differentiated to neural crest cells using the stromal-derived inducing activity (SDIA) of the PA6 mouse embryonic fibroblast cell line. The resulting neural crest cells are selected by their expression of cell-surface CD271 and subsequently cultured as 3D pellets in a defined differentiation medium to induce a keratocyte phenotype. View Publication

Chronic obstructive pulmonary disease (COPD) is a highly prevalent,chronic inflammatory lung disease with limited existing therapeutic options. While modulation of peroxisome proliferator-activating receptor (PPAR)-$$ activity can modify inflammatory responses in several models of lung injury,the relevance of the PPARG pathway in COPD pathogenesis has not been previously explored. Mice lacking Pparg specifically in airway epithelial cells displayed increased susceptibility to chronic cigarette smoke (CS)-induced emphysema,with excessive macrophage accumulation associated with increased expression of chemokines,Ccl5,Cxcl10,and Cxcl15. Conversely,treatment of mice with a pharmacological PPAR$$ activator attenuated Cxcl10 and Cxcl15 expression and macrophage accumulation in response to CS. In vitro,CS increased lung epithelial cell chemokine expression in a PPAR$$ activation-dependent fashion. The ability of PPAR$$ to regulate CS-induced chemokine expression in vitro was not specifically associated with peroxisome proliferator response element (PPRE)-mediated transactivation activity but was correlated with PPAR$$-mediated transrepression of NF-$$B activity. Pharmacological or genetic activation of PPAR$$ activity abrogated CS-dependent induction of NF-$$B activity. Regulation of NF-$$B activity involved direct PPAR$$-NF-$$B interaction and PPAR$$-mediated effects on IKK activation,I$$B$$ degradation,and nuclear translocation of p65. Our data indicate that PPARG represents a disease-relevant pathophysiological and pharmacological target in COPD. Its activation state likely contributes to NF-$$B-dependent,CS-induced chemokine-mediated regulation of inflammatory cell accumulation. View Publication

Non-viral gene delivery into human embryonic stem cells (hESCs)is an important tool for controlling cell fate. However,the delivery efficiency remains low due in part to the tight colony structure of the cells which prevents effective exposure towards delivery vectors. We herein report a novel approach to enhance non-viral gene delivery to hESCs by transiently altering the cell and colony structure. (R)-(+)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide (Y-27632),a small molecule that inhibits the rho-associated protein kinase pathway,is utilized to induce transient colony spreading which leads to increased transfection efficiency by 1.5 to 2 folds in a spectrum of non-viral transfection reagents including Lipofectamine 2000 and Fugene HD. After removal of Y-27632 post-transfection,cells can revert back to its normal state and do not show alteration of pluripotency. This approach provides a simple,effective tool to enhance non-viral gene delivery into adherent hESCs for genetic manipulation. View Publication

Dysbindin is a schizophrenia susceptibility factor and subunit of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) required for lysosome-related organelle biogenesis,and in neurons,synaptic vesicle assembly,neurotransmission,and plasticity. Protein networks,or interactomes,downstream of dysbindin/BLOC-1 remain partially explored despite their potential to illuminate neurodevelopmental disorder mechanisms. Here,we conducted a proteome-wide search for polypeptides whose cellular content is sensitive to dysbindin/BLOC-1 loss of function. We identified components of the vesicle fusion machinery as factors downregulated in dysbindin/BLOC-1 deficiency in neuroectodermal cells and iPSC-derived human neurons,among them the N-ethylmaleimide-sensitive factor (NSF). Human dysbindin/BLOC-1 coprecipitates with NSF and vice versa,and both proteins colocalized in a Drosophila model synapse. To test the hypothesis that NSF and dysbindin/BLOC-1 participate in a pathway-regulating synaptic function,we examined the role for NSF in dysbindin/BLOC-1-dependent synaptic homeostatic plasticity in Drosophila. As previously described,we found that mutations in dysbindin precluded homeostatic synaptic plasticity elicited by acute blockage of postsynaptic receptors. This dysbindin mutant phenotype is fully rescued by presynaptic expression of either dysbindin or Drosophila NSF. However,neither reduction of NSF alone or in combination with dysbindin haploinsufficiency impaired homeostatic synaptic plasticity. Our results demonstrate that dysbindin/BLOC-1 expression defects result in altered cellular content of proteins of the vesicle fusion apparatus and therefore influence synaptic plasticity. View Publication

Unintended exposure to teratogenic compounds can lead to various birth defects; however current animal-based testing is limited by time,cost and high inter-species variability. Here,we developed a human-relevant in vitro model,which recapitulated two cellular events characteristic of embryogenesis,to identify potentially teratogenic compounds. We spatially directed mesoendoderm differentiation,epithelial-mesenchymal transition and the ensuing cell migration in micropatterned human pluripotent stem cell (hPSC) colonies to collectively form an annular mesoendoderm pattern. Teratogens could disrupt the two cellular processes to alter the morphology of the mesoendoderm pattern. Image processing and statistical algorithms were developed to quantify and classify the compounds' teratogenic potential. We not only could measure dose-dependent effects but also correctly classify species-specific drug (Thalidomide) and false negative drug (D-penicillamine) in the conventional mouse embryonic stem cell test. This model offers a scalable screening platform to mitigate the risks of teratogen exposures in human. View Publication