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The Qatar International Conference on Stem Cell Science and Policy
- Conference date: 27-01 Feb-Mar 2012
- Location: Qatar National Convention Center, Doha, Qatar
- Volume number: 2012
- Published: 01 February 2012
41 - 60 of 61 results
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Subependymal zone stem cells and progenitor migration to brain injuries: a critical analysis
More LessAbstractAdult neurogenesis in mammals was rediscovered over twenty years ago and has generated a huge amount of interest as a developmental biology system to study stem cells, proliferation, fate determination and migration. It has also raised hope that these cells may be harnessed to help repair brain injury and disease. Indeed subependymal zone (SEZ) progenitors actively migrate to brain injuries and help replace dead cells and provide protective trophic support. Whereas human neurogenesis after infancy is quite minimal it seems to increase after most degenerative brain diseases. I will argue that more post mortem examination of human neurogenesis is needed. I will also present data from my laboratory that has shown the epidermal growth factor receptor and galectin-3 both modulate migration of SEZ cells. These and other molecular mechanisms may be manipulated to increase the reparative response. We are examining SEZ migration with 2-Photon time-lapse microscopy a technique which allows high temporal spatial resolution of dynamic events. This is helping us discern the natural history of these fascinating tissue specific stem and progenitor cells. We believe this is essential for the field to develop their potential clinical use.
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Clinical translation of human neural stem cells, promise for the future
More LessAbstractCurrently, there are few effective therapies for the treatment of neurodegenerative diseases or injuries to the brain, spinal cord and eye. Human neural stem cell transplants offer the prospect to treat such conditions and represent a potential exciting new medical therapy. A highly purified composition of human neural stem cells has been isolated, expanded and stored as banks of cells, HuCNS-SC®. When transplanted into the brain of immunodeficient rodents, human neural stem cells reside and proliferate in host neurogenic sites, such as the subventricular zone and dentate gyrus of the hippocampus. Their progeny migrate globally throughout the brain and differentiate in a site-appropriate manner into neurons, astrocytes and oligodendrocytes. When transplanted into the spinal cord above and below the injury site, these cells also migrate extensively and differentiate, remyelinate and make synaptic connections with host neurons. HuCNS-SC have also been shown to produce soluble proteins such as housekeeping lysosomal enzymes, neurotrophic factors, and chemokines which may protect damaged host cells and also become mature oligodendrocytes which myelinate dys- or demyelinated host axons. Moreover, these human cells survive long-term in the host brain with no signs of tumor formation or adverse effects and unlike ESC or iPSC, HuCNS-SC do not require pre-differentiation prior to transplant nor do they form teratomas. Therefore, a single transplant of human neural stem cells offers the prospect of a durable clinical benefit. Studies transplanting HuCNS-SC into animal models of human diseases or injury have been performed to assess the cells’ biological properties including their impact on these specific targets. These preclinical efficacy studies have demonstrated protection of host cells and/or improvements in specific functional deficits and provided the foundation for the neuroprotection and neural replacement strategies to support initiation of our clinical studies. Three clinical studies have been initiated to date. The first clinical study in Batten disease, a fatal lysosomal storage disease, has been completed and the surviving patients are now ~4-5 years post-transplant with no safety concerns. A trial in PMD, a fatal myelination disorder, is completing and will examine evidence of de novo myelin formation from transplanted HuCNS-SC. A trial in chronic spinal cord injury has completed dosing of the most severely injured patients and will now enrol those with incomplete thoracic injuries. The Company has recently filed regulatory documents to begin a trial in dry AMD. Preclinical studies in a rat model of retinal degeneration, the RCS rat, have shown cone photoreceptor protection following subretinal transplants of HuCNS-SC. The clinical data derived from these studies should facilitate future clinical testing of HuCNS-SC cells in a broad range of other neurological disorders including Alzheimer’s disease, stroke, and cerebral palsy. In addition to its pioneering efforts in the discovery and development of its proprietary human neural stem cell, the Company’s scientists have also identified a rare cell population from non ideal human adult livers that display the key hallmarks of a therapeutic product for treating liver diseases. Efforts are underway to define optimal expansion conditions to create cell banks of liver-engrafting cells.
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The Embryonic Stem (ES)-specific microRNA, miR-302, is highly expressed in a rare subpopulation of glioma cell lines
More LessAbstractMiR-302s is a cluster of polycistronic microRNAs that are exclusively expressed in embryonic stem (ES) cells. MiR-302s' promoter is functional during embryonic development, but it is turned off in later stages. Based on cancer stem cell hypothesis, some pluripotency-associated genes are re-expressed in some tumor tissues and cell lines. In the present study, we have tried to expand our knowledge about the expression pattern and functionality of miR302s by quantifying its expression in a series of glioma (A-172, 1321N1, U87MG) and medulloblastoma (DAOY) cell lines. Furthermore, to assess the functionality of miR-302 in these cell lines, we cloned its promoter core region upstream of the EGFP or luciferase encoding genes. Our data revealed a very low expression of miR-302s in glioma cell lines, compared to that of embryonal carcinoma cell line NT2 being used as a positive control. The expression of miR-302 promoter-EGFP construct in the aforementioned cell lines demonstrated GFP expression in a rare subpopulation of the cells. Serum deprivation led to the generation of tumorospheres, enrichment of miR-302 positive cells, and upregulation of a number of pluripotency genes. To find out whether miR-302 has a causative role in these events, we transfected the 1321N1 cell line with an expression vector containing the sequences of all miR-302 members. MiR-302s expression caused tumorospheres formation as well as a significant upregulation of pluripotency genes. Taken together, our data introduces a novel putative cancer stem cell marker that could potentially be used to identify and target cancer stem cells within tumor tissues.
Afsaneh Malekzadeh Shafaroudi1, Mahmoud-Reza Rafiee2, Sara Rohban3, Hamid Reza Kalhor4, Seyed Javad Mowla1,3*
1 Parsgenome Company, Tehran, Iran 2 Nanomedicine and Tissue Engineering Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3 Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran 4 Omics Research Center, Golestan University of Medical Sciences, Gorgan, Iran
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Establishing a Legal Foundation for Public Oversight of Clinical Trials
By Mark FrankelAbstractPublic (government) oversight reflects the way society perceives and responds to risk, which is intrinsic to the conduct of experimental research. Such oversight typically takes the form of regulation, which combines organizations, rules and sanctions intended to produce desired behaviors in support of clear objectives. Ensuring a rigorous clinical trial process that also offers proper protections of research subjects requires a legal framework that features the following qualities: (1) must act, and be seen to act, in the public interest; (2) comprised of clear and explicit objectives and requirements; (3) fairness in its application and enforcement; (4) based on dialogue among regulators, the regulated community, and the beneficiaries of regulation; (5) sustains public confidence and trust; and (6) is more likely than other options to achieve its goals. While these features will be applied to stem cell clinical trials, they are also relevant in other areas where science and technology are perceived as posing risks to individuals and/or the larger society.
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The Tragedy of Translation: Epistemological and Ethical Challenges Pertaining to Bringing Stem Cells to the Clinic
More LessAbstractThere is a profound moral question at the heart of all translational research: who should go first in human trials when the risks are not possible to estimate, the trial highly observed, and the effects of failure far-reaching?
This paper aims to address this question by unveiling the epistemological problem at its core. Second, the paper will draw attention to some of the unresolvable ethical challenges underlying any type of translational research involving human beings.
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A Multiple Perspectives Approach to Stem Cell-Based Clinical Trials
By Insoo HyunAbstractPatients, scientists, regulators, and the public may each view early stage stem cell-based clinical trials from varying perspectives and interests. In this talk I explain these various points of view, their differences, and their importance to the ethics of stem cell-based clinical trials. Based on this multiple perspectives analysis, I conclude with some ethical recommendations for the conduct of early stage human trials necessary to advance stem cell science.
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What We Need in the GCC States to Catch-up with Evolving Stem Cell and Regenerative Medicine Research
More LessAbstractEvery year we witness the introduction of new drugs and medical technologies that improve the health and lives of individuals around the world. Stem cell research holds an awesome potential for restructuring the way we practise medicine. One day, stem cell researches will dramatically alter the way we treat diseases.
Since the first human ES cell lines were derived more than a decade ago, hundreds have been created worldwide, including lines suitable for clinical application. As such, it involves questions of ethics that are commonly raised in research, such as preserving research integrity and the use of human tissue and animals in research. Moreover, there is much to be investigated about the specific characteristics of stem cells and about the efficacy and safety of the new drugs based on this type of cells, both embryonic and adult stem cells, for several therapeutic indications.
The current reality is that, although extensive researches are ongoing and encouraging partial results are being achieved, there is still much to do in the GCC states to orchestrate the stem cell and regenerative medicine research.
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Reconciling Multiple Standards
Authors: Kip Kantelo and Pablo Rodriguez Del PozoAbstractStem cell research by Weill Cornell Medical College in Qatar (WCMC-Q) is subject to the ethical standards of both the Qatar Supreme Council of Health (SCH) and the National Academies of Sciences (NAS) in the United States (US). The authors examined their personal experiences with the policy-making process in Qatar and the ethical review process in both Qatar and the US. The objectives of this examination were to characterize different approaches to ethical oversight of stem cell research; consider factors underlying the different approaches; identify advantages and shortcomings of the approaches;and suggest areas where the approaches could enrich each other.
The authors identified two different approaches. First, Top-down, in which a centralized agency passes a set of regulations, often drawn from different international experiences and intended to be complete and stable. This is the model followed in Qatar. Secondly, Bottom-up, in which various agents (researchers, universities, funders, and others) reach a level of consensus and produce non-mandatory guidelines including a set of principles and accompanying specific points. Institutions later adopt the guidelines. This is the approach of the NAS.
Each approach results from the interplay of several factors, including Local experience, Organization of the state, and Political culture.
Top-down is rapidly available and provides a clear, monolithic framework, generally with few internal contradictions.
However, speed and consistency may limit flexibility. There may not be room for ethically acceptable alternative solutions if the framework poses scientific or practical difficulties. Top-down regulation runs the risk of rapid obsolescence in a dynamic field.
Bottom-up, being the product of deliberation, tends to be more flexible. However, this approach risks being hijacked by interminable discussions. Guidelines are not always immediately available. In a decentralized environment, competing guidelines may emerge. Approaches can enrich each other by establishingbasic guiding principles to inform detailed rules; avoiding too much detail that will be difficult to change; maintaining a mix of guidelines and regulation to provide certainty and flexibility while avoiding arbitrariness; adjusting according to experience of and feedback from stakeholders; and accepting imperfection in details and implementation.
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Attachment of Embryonic Stem Cells-derived Cardiomyocytes in Cultispher-S Microcarriers by using Spinner flask
More LessAbstractEmbryonic Stem cells have the ability to differentiate under in vitro conditions into cardiomyocytes. A transgenic α-myosin heavy chain (α-MHC+) ES cell line was generated, exhibiting puromycin resistance and expressing enhanced green fluorescent protein (EGFP) under control of the α-MHC+ promoter. A puromycin-resistant, EGFP-positive α-MHC+ cardiomyocyte population was isolated with over 92 percent purity.
The cultivation of these cardiomyocytes, in macroporous gelatine microsphere beads in a spinner flask bioreactor has been studied. The average number of cultivated cells per microsphere was optimised after we specified the most suitable agitation conditions and the optimal time frames of cultivation. Our study shows that 80 percent of microspheres were colonised by cardiomyocytes under optimal conditions. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to show that the population of the beads was not limited to the microcarrier surface, but some cells invaded the inner surfaces of the microspheres as well.
The present findings demonstrate the successful culture of α-MHC+ cardiomyocytes in macroporous biodegradable microcarriers while maintaining the typical morphological and electrophysiological properties of cardiomyocytes. Our perspective significantly improves survival of grafted cardiomyocytes and thus helps to overcome current limitations of cell replacement approaches
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Comparative Analysis of Major World Religious Doctrines on Human Stem Cell Research
By Alan WeberAbstractThe objective was to compare the religious doctrine on human stem cell research in the faiths of: Christianity, Islam, Judaism, Hinduism, and Buddhism. The method used was the analysis of theology texts. Results showed that Locus = human potentiality, sanctity of life, soul and conceptus, subject vulnerability, cell line ownership, eugenics. We concluded that an international co-operative agreement is difficult to achieve.
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Propagation and Osteogenic Differentiation of Human Mesenchymal Stem Cells derived from Prenatal and Postnatal Sources
More LessAbstractThe application of mesenchymal stem cells differentiated into osteogenic cells is an attractive care modality to enhance the healing process of orthopedics and spinal injuries. Objectives of the in-vitro part of our study are: 1. To isolate and propagate Mesenchymal stem cells ( MSCs) derived from different sources; Bone Marrow (BM), Dental Pulp (DP), and Amniotic Fluid (AF) and 2. Induce their osteogenic differentiation in vitro.
Methods used were the generation and optimization of in-vitro cultures for DP- BM- and AF-MSCs, followed by their osteogenic differentiation by applying three independent induction protocols; osteogenic reagents containing media, bone morphologic protein2 (BMP2), and combined BMP2 and insulin growth factor (IGF).
The results showed that MSCs derived from different sources showed a significant difference both in the proliferation rate and osteogenic differentiation potentials. Whereas, DP-MSCs showed the highest proliferation rate, the AF-MSCs showed the greatest potential to osteogenic differentiation, whereas, BM-MSCs have the least potential toward osteogenic differentiation. In conclusion, the tissue of origin of derived MSCS is greatly influenced by the lineage of differentiation of derived stem cells.
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Understanding Families and Communities Hold the Key of Implementing New Technologies
By Anna RajabAbstractOver the past few years, GCC countries have witnessed remarkable social and economic growth, which is best reflected in their well-organized and efficient health care systems. With these achievements, a shift in the pattern of disease has become evident. There has been a change in a disease pattern with a falling incidence of communicable diseases, decrease of mortality and morbidity rates of infants and children and a rise in noncommunicable conditions.
Families in GCC states can benefit from new genetic approaches, but these need to be designed to conform with the community beliefs and culture. Presently, GCC communities need help in coping with the changes and challenges that genetic knowledge brings to their lives.
Understanding social beliefs, respect of the traditions set up in an Islamic community, and understanding the psychological difficulties faced by families are essential for acceptance of new technological advances. The difficulties faced by families and proposed solutions are discussed.
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Identification of Two Novel Splice variants of SOX2OT which are Co-expressed with Pluripotency Genes during Neural Differentiation of Stem Cells
More LessAbstractOur objectives were: Long non-coding RNAs (lncRNAs) are emerging as new regulators of stem cell pluripotency and neurogenesis. Recent studies revealed that the expression of several lncRNAs correlates with the expression of pluripotency regulators such as OCT4 and Nanog. Surprisingly, the SOX2 gene, another master regulator of pluripotency, is embedded within an intron of an lncRNA, known as SOX2OT. SOX2OT and has been suspected to participate in regulation of the SOX2 expression and related processes; nevertheless, its function has still remained untested. In this study, we investigated a potential correlation between the expression pattern of SOX2OT, also its newly discovered splice variants (SOX2OT-S1 and SOX2OT-S2) and master regulators of stem cell pluripotency (SOX2 and OCT4) in mesenchymal stem cells, as well as during the course of neural differentiation of the human EC cell line, NTERA2 (NT2).
We treated the NT2 cells with all-trans retinoic acid (ATRA) for four weeks to differentiate into neural phenotype. By designing specific primers for real-time PCR, we evaluated the expression pattern of SOX2OT, SOX2OT-S1, SOX2OT-S2, SOX2 and OCT4 in mesenchymal stem cells and also during the induction of neural differential of NT2 cells.
Our results showed that by using a different set of primers, we discovered two novel variants of SOX2OT, named SOX2OT-S1 (lacking exon4) and SOX2OT-S2 (lacking exons3 and 4). The expression pattern of SOX2OT variants was positively correlated with the expression of SOX2 and OCT4 in NT2 cells. Surprisingly, SOX2OT variants showed a distinct expression pattern during the course of neural differentiation of NT2 cells. The expression pattern of SOX2OT variants was similar to that of OCT4 and SOX2 during early differentiation of NT2 cells. However, in contrast to OCT4 and SOX2, a low expression of SOX2OT variants persist in later time points of neural differentiation of NT2 cells.
We found that close correlation between the expression pattern of SOX2OT variants and master regulators of pluripotency (OCT4 and SOX2) suggests that they may be involved in similar regulatory pathways including: self-renewal, pluripotency, and differentiation.
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Unravelling Ovarian Cancer Stem Cells Physiology
Authors: H Al Farsi, R Lis, H Al Thawadi, D Azzazen, J Soria, A Therwat, E Pujade Laurain and M MirshahiAbstractOvarian cancer is a highly metastatic disease. Epithelial ovarian cancer is the most lethal gynecologic malignancy with the majority of cases being diagnosed after the disease has become metastatic. Recent reports have shown that 25% of cancerous cells within tumors have features of cancer stem cells (CSCs). CSCs have been identified on the basis of their ability for self-renewal and to have the capacity to differentiate into cancer cells and also form tumors in animal models. EMT describes a mechanism by which cells lose their epithelial characteristics and acquire more migratory mesenchymal properties. It also seems to have a key role in the acquisition of invasive and migratory properties in many types of carcinoma cells. The aim of this study is to understand the molecular changes and signaling pathways associated with ovarian cancer cell transformation which may lead to the identification of targets for novel therapeutic interventions.
OVCAR-3 and hospicells were cultured in vitro according to standard procedure. OVCAR cells were stained using anti CD133 –prominin-1 and anti CD117-APC and sorted by FACS system as positive and negative. The supernatant of OVCAR CD117+ and CD117- were analyzed by cytokine array And 174 different membrane coupled anti-cytokines along with appropriate controls were studied. The gene expression patterns of OVCAR-3 cultured with supernatant of Hospicells (clone M16) or control cells were analysed and compared by a two-colour topic-defined microarray. The products of microarray consisted of genes related to cytokines, interleukins and growth factors. The up regulated 86 codes genes were analysed by DAVID functional annotation tool.
We demonstrated that OVCAR-3 cell line for several reasons did not appear to be monoclonal. It contains tow subpopulations: one expressing CD117 and the other not. The fact that OVCAR-3 expresses at the same time CD133 and CD117 is indicative of the stem cell nature of this cell line. The cytokines secreted by CD117+ and CD117- were not the same and indicate the different profile of these cells in cell behavior. Analysis was of OVCAR gene array after 8h incubation of Hospicells by DAVID functional annotation tool intricate gpl 130 (IL6 ST) cytokine receptor interaction (IL6, IL11, OSM, LIF, CNTF ligands) and angiogenic factors expression.
We found that OVCAR-3 is apparently a suitable model for studying ovarian cancer stem cells and Epithelial to Mesenchymal Transition in Ovarian Cancer Cells.
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Influence of Active and Non-active Protein C on Human Ovarian Cancer Stem Cells
Authors: H Al Thawadi, S Mirshahi, H Al Farsi, D Azzazen, S Besbes, E Pujade-Laurain, A Therwath, J Soria and M MirshahiAbstractIntroduction: The coagulation/fibrinolysticsystem control the intravascular fibrin hemostasis;in addition to participating in a wide variety of physio-pathological processes. The components of the system have an influence on tumor growth, invasion and metastasis. This is a result of their involvement in tumor matrix construction, angiogenesis and cell migration. Several homeostatic markers are currently used to predict the advent of thrombosis. However, none of these markers directly indicate the course and progression of the disease. Destabilization of peri-tumoral matrix enhances the malignant phenotype of cancer cells. The characterization of cytokines and proteolytic enzymes, secreted in tumor microenvironment, plays an important role in the mechanism of the escape phenomenon. However, the consequence of interaction of protein C on cancer stem cells is poorly investigated.
Objective: The aim of our study was to analyze the physio-pathological response of human ovarian cancer stem cells (OVCAR-3) to active and non-active protein C.
OVCAR-3 cells were cultured in DMEM medium containing 10% fetal calf serum, penicillin (50 U/ml), and streptomycin (50 μg/ml) and incubated in a humidified atmosphere containing 5% CO2 at 37°C, as recommended by the supplier (PAA Laboratories Inc, Etobicoke, ON, USA). Cells were characterized by flow cytometry for their propriety of stem cell like with specific anti CD133 and CD117 antibodies. The influence of active and non-active protein C (10 µg/ml, Eli Lilly) on this cell was performed by cytokine array (Ray Biotech, CliniScience) and in parallel by a wound healing test.
We demonstrated by a wound healing test that the migration of ovarian cancer cells enhanced when incubated with Active protein C compared to the cells that were incubated with Non-active protein C. Also the cytokine array showed different cytokines secreted by cells incubated with Active protein C and Non-active protein C.
It was found that Active protein C not only provides cancer cells cytoprotective effects, it may also participate in extracellular matrix local destabilization, thereby promoting metastatic dissemination.
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Gene Expression Profiling of Embryonic Human Neural Stem Cells and Dopaminergic Neurons from Adult Human Substantia Nigra
AbstractNeural stem cells (NSC) with self-renewal and multipotent properties serve as an ideal cell source for transplantation to treat neurodegenerative insults such as Parkinson's disease. We used Agilent's and Illumina Whole Human Genome Oligonucleotide Microarray to compare the genomic profiles of human embryonic NSC at a single time point in culture, and a multicellular tissue from postmortem adult substantia nigra (SN) which are rich in dopaminergic (DA) neurons. We identified 13525 up-regulated genes in both cell types of which 3737 (27.6%) genes were up-regulated in the hENSC, 4116 (30.4%) genes were up-regulated in the human substantia nigra dopaminergic cells, and 5672 (41.93%) were significantly up-regulated in both cell population. Careful analysis of the data that emerged using DAVID has permitted us to distinguish several genes and pathways that are involved in dopaminergic (DA) differentiation, and to identify the crucial signaling pathways that direct the process of differentiation.
The set of genes expressed more highly at hENSC is enriched in molecules known or predicted to be involved in the M phase of the mitotic cell cycle. On the other hand, the genes enriched in SN cells include a different set of functional categories, namely synaptic transmission, central nervous system development, structural constituents of the myelin sheath, the internode region of axons, myelination, cell projection, cell somata, ion transport, and the voltage-gated ion channel complex. Our results were also compared with data from various databases, and between different types of arrays, Agilent versus Illumina. This approach has allowed us to confirm the consistency of our obtained results for a large number of genes that delineate the phenotypical differences of embryonic NSCs, and SN cells.
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Programming Human Pluripotent Stem Cells into White and Brown Adipocytes
More LessAbstractThe utility of human pluripotent stem cells is dependent on efficient differentiation protocols that convert these cells into relevant adult cell types. Here we report the robust and efficient differentiation of human pluripotent stem cells into white or brown adipocytes. We found that inducible expression of PPARG2 alone or combined with CEBPB and/or PRDM16 in mesenchymal progenitor cells derived from pluripotent stem cells programmed their development towards a white or brown adipocyte cell fate with efficiencies of 85–90 percent. These adipocytes retained their identity independent of transgene expression, could be maintained in culture for several weeks, expressed mature markers and had mature functional properties such as lipid catabolism and insulin-responsiveness. When transplanted into mice, the programmed cells gave rise to ectopic fat pads with the morphological and functional characteristics of white or brown adipose tissue. These results indicate that the cells could be used to faithfully model human disease.
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Ethical, Legal, and Social Issues on the Recruit Process of Healthy Volunteers for Induced Pluripotent Stem Cell bank at Kyoto University
By Ken OkadaAbstractBanking of biomedical tissues or information related to them has been conducted around the world for clinical, research and/or commercial purposes. In addition to stem cells in the differentiated tissues such as cord blood and bone marrow, pluripotent stem cells are also subjects of banking. Human embryonic stem cells (hES cells) are one type of these cells, but induced pluripotent stem cells (iPS cells) are now also subjects of banking for various purposes.
In Japan, the Center for iPS Cell Research and Application (CiRA), led by Dr Shinya Yamanaka, was established in 2010 to conduct research on iPS cells. In order to realize iPS cell based therapies, CiRA is now working to establish a new iPS cell bank. The bank aims to establish clinical-grade, HLA-matched iPS cell lines from healthy volunteers and store them to provide for therapeutic or research use. Although some iPS cell banks in Japan or in other countries, including the one in CiRA, are already established, these banks store and provide basically disease-specific iPS cell lines. Therefore, the planned iPS cell bank at CiRA is unique in that it is going to store and provide clinical-grade iPS cells derived from healthy volunteers.
We have been collaborating with researchers at CiRA to establish appropriate procedures for the recruitment of healthy volunteers. We have found that there are a variety of ethical, legal, and social issues (ELSI) that need to be addressed. Since iPS cells are pluripotent stem cells, some ELSI are similar to those already identified in hES cell banks. However, there are other issues that are relatively novel and specific to iPS cells, especially when the donor is a healthy volunteer, not a patient. These ELSI identified arise because: 1. these cells are derived from healthy volunteers; 2. these cells expand infinitely; and 3. the bank deals not only with information such as genome sequence but also with other aspects of the cells.
In this presentation, we will summarize and discuss the ELSI we encountered while establishing the process of healthy-volunteer recruitment for the iPS cell bank.
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Soluble CD40 Ligand Stimulates the Pro-Angiogenic Function of Early Endothelial Progenitor Cells by Increasing Matrix Metalloproteinase 9 Release via the p38 Mitogen Activated Protein Kinase Pathway
Authors: Lara Bou Khzam, Haissam Abou-Saleh, Ahmed Hachem, Younes Zaid, Walid Mourad and Yahye MerhiAbstractEndothelial progenitor cells (EPCs) have recently been regarded as potential therapeutic targets in vascular repair. The effects of EPCs are related to their incorporation at sites of vascular lesions and to their release of various angiogenic factors. It has been shown that soluble CD40 ligand (sCD40L) levels are elevated in patients suffering from cardiovascular disease, which may influence the function of EPCs. We have identified the expression of the inflammatory receptor CD40 on early EPCs and aimed to study the effect of its ligand, sCD40L, on the function of early EPCs in angiogenesis.
Early EPCs derived from cultured peripheral blood mononuclear cells express CD40, and their stimulation with sCD40L increased the binding of the tumor necrosis factor receptor-associated factors, TRAF1, TRAF2, but not TRAF3, to CD40, indicating the existence of a functional signaling pathway via the CD40L/CD40 axis in early EPCs. Early EPCs alone do not display any tube formation potential on matrigel, but following stimulation with sCD40L, they significantly increased the angiogenic potential of cultured human umbilical vein endothelial cells (HUVECs), as determined by wound healing assay. Stimulation of early EPCs with sCD40L increased, in a concentration-dependent manner, the release of matrix metalloproteinase 9 (MMP-9) via the p38 mitogen activated protein kinase (MAPK) pathway. Inhibition of p38 MAPK, by SB203580, in sCD40L-treated early EPCs, reversed their release of MMP-9 and their pro-angiogenic effect on HUVECs.
We have shown that sCD40L increases the pro-angiogenic function of early EPCs on cultured HUVECs by inducing a significant increase in MMP-9 release via the p38 MAPK signaling pathway.
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Mechanotransduction Modulates the Effect of Mechanical Forces (fluid shear stress and cyclic strain) on Embryonic Stem Cell Differentiation toward Vascular Endothelial and Smooth Muscle Cells
Authors: Maria Nikmanesh, Zhong-Dong Shi and John TarbellAbstractIt has been shown that shear stress plays a critical role in promoting endothelial cell (EC) differentiation from embryonic stem cell (ESC)-derived ECs. However, the underlying mechanisms mediating shear stress effects in this process have yet to be investigated. It has been reported that the glycocalyx component heparan sulfate proteoglycan (HSPG) mediates shear stress mechanotransduction in mature EC.
In this study, we investigated whether cell surface HSPG plays a role in shear stress modulation of EC phenotype. ESC-derived EC were subjected to shear stress (5 dyn/cm(2) ) for 8h with or without heparinase III (Hep III) that digests heparan sulfate. Immunostaining showed that ESC-derived EC surfaces contain abundant HSPG, which could be cleaved by Hep III. We observed that shear stress significantly increased the expression of vascular EC-specific marker genes (vWF, VE-cadherin, PECAM-1. The effect of shear stress on expression of tight junction protein genes (ZO-1, OCLD, CLD5) was also evaluated. Shear stress increased the expression of ZO-1 and CLD5, while it did not alter the expression of OCLD. Shear stress increased expression of vasodilatory genes (eNOS, COX-2), while it decreased the expression of the vasoconstrictive gene ET1. After reduction of HSPG with Hep III, the shear stress-induced expression of vWF, VE-cadherin, ZO-1, eNOS, and COX-2, were abolished, suggesting that shear stress-induced expression of these genes depends on HSPG. These findings indicate for the first time that HSPG is a mechanosensor mediating shear stress-induced EC differentiation from ESC-derived EC cells.
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