Scientific Resources

BACKGROUND Humanized mouse models are still under development,and various protocols exist to improve human cell engraftment and function. METHODS Fourteen NOD/SCID/IL-2Rγnull (NSG) mice (4‒5 wk old) were conditioned with busulfan and injected with human umbilical cord blood (hUCB)-derived CD34(+) hematopoietic stem cells (HSC) via retro-orbital sinuses. The bone marrow (BM),spleen,and peripheral blood (PB) were analyzed 8 and 12 weeks after HSC transplantation. RESULTS Most of the NSG mice tolerated the regimen well. The percentage of hCD45(+) and CD19(+) cells rose significantly in a time-dependent manner. The median percentage of hCD45(+)cells in the BM was 55.5% at week 8,and 67.2% at week 12. The median percentage of hCD45(+) cells in the spleen at weeks 8 and 12 was 42% and 51%,respectively. The median percentage of hCD19(+) cells in BM at weeks 8 and 12 was 21.5% and 39%,respectively (P=0.04). Similarly,the median percentage of hCD19(+) cells in the spleen at weeks 8 and 12 was 10% and 24%,respectively (P=0.04). The percentage of hCD19(+) B cells in PB was 23% at week 12. At week 8,hCD3(+) T cells were barely detectable,while hCD7(+) was detected in the BM and spleen. The percentage of hCD3(+) T cells was 2‒3% at week 12 in the BM,spleen,and PB of humanized NSG mice. CONCLUSION We adopted a simplified protocol for establishing humanized NSG mice. We observed a higher engraftment rate of human CD45(+) cells than earlier studies without any significant toxicity. And human CD45(+) cell engraftment at week 8 was comparable to that of week 12. View Publication

We have established an in vitro 3D system which recapitulates the human tracheo-bronchial mucosa comprehensive of the pseudostratified epithelium and the underlying stromal tissue. In particular,we reported that the mature model,entirely constituted of primary cells of human origin,develops key markers proper of the native tissue such as the mucociliary differentiation of the epithelial sheet and the formation of the basement membrane. The infection of the pseudo-tissue with a strain of NonTypeable Haemophilus influenzae results in bacteria association and crossing of the mucus layer leading to an apparent targeting of the stromal space where they release large amounts of vesicles and form macro-structures. In summary,we propose our in vitro model as a reliable and potentially customizable system to study mid/long term host-pathogen processes. View Publication

BACKGROUND The Tbx3 transcription factor is over-expressed in breast cancer,where it has been implicated in proliferation,migration and regulation of the cancer stem cell population. The mechanisms that regulate Tbx3 expression in cancer have not been fully explored. In this study,we demonstrate that Tbx3 is repressed by the tumour suppressor miR-206 in breast cancer cells. METHODS Bioinformatics prediction programmes and luciferase reporter assays were used to demonstrate that miR-206 negatively regulates Tbx3. We examined the impact of miR-206 on Tbx3 expression in breast cancer cells using miR-206 mimic and inhibitor. Gene/protein expression was examined by quantitative reverse-transcription-PCR and immunoblotting. The effects of miR-206 and Tbx3 on apoptosis,proliferation,invasion and cancer stem cell population was investigated by cell-death detection,colony formation,3D-Matrigel and tumorsphere assays. RESULTS In this study,we examined the regulation of Tbx3 by miR-206. We demonstrate that Tbx3 is directly repressed by miR-206,and that this repression of Tbx3 is necessary for miR-206 to inhibit breast tumour cell proliferation and invasion,and decrease the cancer stem cell population. Moreover,Tbx3 and miR-206 expression are inversely correlated in human breast cancer. Kaplan-Meier analysis indicates that patients exhibiting a combination of high Tbx3 and low miR-206 expression have a lower probability of survival when compared with patients with low Tbx3 and high miR-206 expression. These studies uncover a novel mechanism of Tbx3 regulation and identify a new target of the tumour suppressor miR-206. CONCLUSIONS The present study identified Tbx3 as a novel target of tumour suppressor miR-206 and characterised the miR-206/Tbx3 signalling pathway,which is involved in proliferation,invasion and maintenance of the cancer stem cell population in breast cancer cells. Our results suggest that restoration of miR-206 in Tbx3-positive breast cancer could be exploited for therapeutic benefit. View Publication

Purinergic signaling mediated by P2 receptors (P2Rs) plays important roles in embryonic and stem cell development. However,how it mediates Ca2+ signals in human embryonic stem cells (hESCs) and derived cardiovascular progenitor cells (CVPCs) remains unclear. Here,we aimed to determine the role of P2Rs in mediating Ca2+ mobilizations of these cells. hESCs were induced to differentiate into CVPCs by our recently established methods. Gene expression of P2Rs and inositol 1,4,5-trisphosphate receptors (IP3Rs) was analyzed by quantitative/RT-PCR. IP3R3 knockdown (KD) or IP3R2 knockout (KO) hESCs were established by shRNA- or TALEN-mediated gene manipulations,respectively. Confocal imaging revealed that Ca2+ responses in CVPCs to ATP and UTP were more sensitive and stronger than those in hESCs. Consistently,the gene expression levels of most P2YRs except P2Y1 were increased in CVPCs. Suramin or PPADS blocked ATP-induced Ca2+ transients in hESCs but only partially inhibited those in CVPCs. Moreover,the P2Y1 receptor-specific antagonist MRS2279 abolished most ATP-induced Ca2+ signals in hESCs but not in CVPCs. P2Y1 receptor-specific agonist MRS2365 induced Ca2+ transients only in hESCs but not in CVPCs. Furthermore,IP3R2KO but not IP3R3KD decreased the proportion of hESCs responding to MRS2365. In contrast,both IP3R2 and IP3R3 contributed to UTP-induced Ca2+ responses while ATP-induced Ca2+ responses were more dependent on IP3R2 in the CVPCs. In conclusion,a predominant role of P2Y1 receptors in hESCs and a transition of P2Y-IP3R coupling in derived CVPCs are responsible for the differential Ca2+ mobilization between these cells. View Publication

Inducing cardiomyocyte proliferation in post-mitotic adult heart tissue is attracting significant attention as a therapeutic strategy to regenerate the heart after injury. Model animal screens have identified several candidate signalling pathways,however,it remains unclear as to what extent these pathways can be exploited,either individually or in combination,in the human system. The advent of human cardiac cells from directed differentiation of human pluripotent stem cells (hPSCs) now provides the ability to interrogate human cardiac biology in vitro,but it remains difficult with existing culture formats to simply and rapidly elucidate signalling pathway penetrance and interplay. To facilitate high-throughput combinatorial screening of candidate biologicals or factors driving relevant molecular pathways,we developed a high-density microbioreactor array (HDMA) - a microfluidic cell culture array containing 8100 culture chambers. We used HDMAs to combinatorially screen Wnt,Hedgehog,IGF and FGF pathway agonists. The Wnt activator CHIR99021 was identified as the most potent molecular inducer of human cardiomyocyte proliferation,inducing cell cycle activity marked by Ki67,and an increase in cardiomyocyte numbers compared to controls. The combination of human cardiomyocytes with the HDMA provides a versatile and rapid tool for stratifying combinations of factors for heart regeneration. View Publication

Adipose-derived stem cells (ASCs) have received considerable attention in oncology because of the known direct link between obesity and cancer as well as the use of ASCs in reconstructive surgery after tumor ablation. Previous studies have documented how cancer cells commandeer ASCs to support their survival by altering extracellular matrix (ECM) composition and stiffness,migration,and metastasis. This study focused on delineating the effects of ASCs and adipocytes on the self-renewal of stem/progenitor cells and hierarchy of breast epithelial cells. The immortalized breast epithelial cell line MCF10A,ductal carcinoma in situ (DCIS) cell lines MCF10DCIS.com and SUM225,and MCF10A overexpressing SRC oncogene were examined using a mammosphere assay and flow cytometry for the effects of ASCs on their self-renewal and stem-luminal progenitor-differentiated cell surface marker profiles. Interestingly,ASCs promoted the self-renewal of all cell types except SUM225. ASC co-culture or treatment with ASC conditioned media (CM) altered the number of CD49fhigh/EpCAMlow basal/stem-like and CD49fmedium/EpCAMmedium luminal progenitor cells. Among multiple factors secreted by ASCs,IFN$$ and HGF displayed unique actions on epithelial cell hierarchy. IFN$$ increased stem/progenitor-like cells while simultaneously reducing the size of mammospheres,whereas HGF increased the size of mammospheres with an accompanying increase in luminal progenitor cells. ASCs expressed higher levels of HGF,whereas adipocytes expressed higher levels of IFN$$. Since luminal progenitor cells are believed to be prone for transformation,IFN$$ and HGF expression status of ASCs may influence susceptibility for developing breast cancer as well as on outcomes of autologous fat transplantation on residual/dormant tumor cells. IMPLICATIONS This study suggests that the ratio of adipose-derived stem cells to adipocytes influences cancer cell hierarchy,which may impact incidence and progression. View Publication

An expanded hexanucleotide repeat in a noncoding region of the C9orf72 gene is a major cause of amyotrophic lateral sclerosis (ALS),accounting for up to 40% of familial cases and 7% of sporadic ALS in European populations. We have generated induced pluripotent stem cells (iPSCs) from fibroblasts of patients carrying C9orf72 hexanucleotide expansions,differentiated these to functional motor and cortical neurons and performed an extensive phenotypic characterization. In C9orf72 iPSC-derived motor neurons,decreased cell survival is correlated with dysfunction in Ca(2+) homeostasis,reduced levels of the anti-apoptotic protein Bcl-2,increased endoplasmic reticulum (ER) stress and reduced mitochondrial membrane potential. Furthermore,C9orf72 motor neurons,and also cortical neurons,show evidence of abnormal protein aggregation and stress granule formation. This study is an extensive characterization of iPSC-derived motor neurons as cellular models of ALS carrying C9orf72 hexanucleotide repeats,which describes a novel pathogenic link between C9orf72 mutations,dysregulation of calcium signalling and altered proteostasis and provides a potential pharmacological target for the treatment of ALS and the related neurodegenerative disease frontotemporal dementia (FTD). This article is protected by copyright. All rights reserved. View Publication

Pronase treatment is used in the flow cytometry crossmatch (FCXM) to prevent nonspecific antibody binding on B cells. However,we have observed unexpected positive results with pronase-treated T cells in human immunodeficiency virus (HIV)-infected patients. In this study,25 HIV-infected patients without HLA antibodies were tested with pronase-treated and nontreated cells. HIV-positive sera were pretreated with reducing agents and preabsorbed with pronase-treated and nontreated T or B cells before crossmatching. All patients displayed FCXM reactivity with pronase-treated T cells but not with nontreated T cells. None of the patients exhibited FCXM reactivity with pronase-treated and nontreated B cells. These patients displayed FCXM reactivity with pronase-treated CD4+ and CD8+ T cells but not with their nontreated counterparts. Preabsorption with pronase-treated T cells reduced the T cell FCXM reactivity. Preabsorption with pronase-treated B cells or nontreated T and B cells did not have any effect on the T cell FCXM reactivity. Pretreatment with reducing agents did not affect the T cell FCXM reactivity. 15 of 21 HIV-infected kidney allograft recipients with pronase-treated T cell FCXM reactivity display long-term graft survival (1193±631days). These data indicate that HIV-infected patients have nondeleterious autoantibodies recognizing cryptic epitopes exposed by pronase on T cells. View Publication

We asked this question: in normal humans,is either a normal dietary intake or normal serum concentration of phosphorus a determinant of the serum concentration of 1,25(OH)2D? In seven normal men whose dietary phosphorus was decreased from 2,300 to 625 mg/d,each intake for 8-9 d,under strictly controlled,normal metabolic conditions,we measured serum concentrations of 1,25(OH)2D daily,and concentrations of phosphorus hourly throughout a 24-h period,before and after restriction. Decreasing dietary phosphorus induced: (a) a 58% increase in serum levels of 1,25(OH)2D; (b) a 35% decrease in serum levels of phosphorus measured in the afternoon; (c) a 12% decrease in the 24-h mean serum level of phosphorus; but,(d) no decrease in morning fasting levels of phosphorus. Serum concentrations of 1,25(OH)2D varied inversely and significantly with 24-h mean concentrations of phosphorus (r = -0.77,P less than 0.001). When these data are combined with those of our prior study in which dietary phosphorus was varied over an extreme range,the relationship between serum levels of 1,25(OH)2D and 24-h mean serum levels of phosphorus is even stronger (r = -0.90,P less than 0.001). In the aggregate,the results demonstrate that in normal men,dietary phosphorus throughout a normal range and beyond,can finely regulate the renal production and serum concentration of 1,25(OH)2D,and provide evidence that this regulation is mediated by fine modulation of the serum concentration of phosphorus. View Publication

BACKGROUND Neuritic degeneration is an important early pathological step in neurodegeneration. AIM The purpose of this study was to explore the mechanisms connecting neuritic degeneration to the functional and morphological remodeling of endoplasmic reticulum (ER) and mitochondria. METHODS Here,we set up neuritic degeneration models by neurite cutting-induced neural degeneration in human-induced pluripotent stem cell-derived neurons. RESULTS We found that neuritic ER becomes fragmented and forms complexes with mitochondria,which induces IP3R-dependent mitochondrial Ca(2+) elevation and dysfunction during neuritic degeneration. Furthermore,mitochondrial membrane potential is required for ER fragmentation and mitochondrial Ca(2+) elevation during neuritic degeneration. Mechanically,tightening of the ER-mitochondria associations by expression of a short synthetic linker" and ER Ca(2+) releasing together could promote mitochondrial Ca(2+) elevation� View Publication

Background: Huntington's disease (HD) is an incurable hereditary neurodegenerative disorder,which manifests itself as a loss of GABAergic medium spiny (GABA MS) neurons in the striatum and caused by an expansion of the CAG repeat in exon 1 of the huntingtin gene. There is no cure for HD,existing pharmaceutical can only relieve its symptoms. Results: Here,induced pluripotent stem cells were established from patients with low CAG repeat expansion in the huntingtin gene,and were then efficiently differentiated into GABA MS-like neurons (GMSLNs) under defined culture conditions. The generated HD GMSLNs recapitulated disease pathology in vitro,as evidenced by mutant huntingtin protein aggregation,increased number of lysosomes/autophagosomes,nuclear indentations,and enhanced neuronal death during cell aging. Moreover,store-operated channel (SOC) currents were detected in the differentiated neurons,and enhanced calcium entry was reproducibly demonstrated in all HD GMSLNs genotypes. Additionally,the quinazoline derivative,EVP4593,reduced the number of lysosomes/autophagosomes and SOC currents in HD GMSLNs and exerted neuroprotective effects during cell aging. Conclusions: Our data is the first to demonstrate the direct link of nuclear morphology and SOC calcium deregulation to mutant huntingtin protein expression in iPSCs-derived neurons with disease-mimetic hallmarks,providing a valuable tool for identification of candidate anti-HD drugs. Our experiments demonstrated that EVP4593 may be a promising anti-HD drug. [ABSTRACT FROM AUTHOR] View Publication

AIM To evaluate the tumor localization and efficacy pH-responsive expansile nanoparticles (eNPs) as a drug delivery system for pancreatic peritoneal carcinomatosis (PPC) modeled in nude rats. METHODS & MATERIALS A Panc-1-cancer stem cell xeno1graft model of PPC was validated in vitro and in vivo. Tumor localization was tracked via in situ imaging of fluorescent eNPs. Survival of animals treated with paclitaxel-loaded eNPs (PTX-eNPs) was evaluated in vivo. RESULTS The Panc-1-cancer stem cell xenograft model recapitulates significant features of PPC. Rhodamine-labeled eNPs demonstrate tumor-specific,dose- and time-dependent localization to macro- and microscopic tumors following intraperitoneal injection. PTX-eNPs are as effective as free PTX in treating established PPC; but,PTX-eNPs result in fewer side effects. CONCLUSION eNPs are a promising tool for the detection and treatment of PPC. View Publication