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Changing the public perception of human embryology. Nat Cell Biol 2023; 25:1717-1719. [PMID: 37985870 DOI: 10.1038/s41556-023-01289-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
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Author Correction: Changing the public perception of human embryology. Nat Cell Biol 2023; 25:1884. [PMID: 38012405 DOI: 10.1038/s41556-023-01319-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
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Happy 10 th anniversary, Stem Cell Reports! Stem Cell Reports 2023; 18:1252-1254. [PMID: 37315518 DOI: 10.1016/j.stemcr.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 05/18/2023] [Indexed: 06/16/2023] Open
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Getting to the heart of stem cell research: an interview with Christine Mummery. Dis Model Mech 2023; 16:dmm050270. [PMID: 37218469 PMCID: PMC10233713 DOI: 10.1242/dmm.050270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023] Open
Abstract
Professor Christine Mummery has pioneered the use of pluripotent stem cell models to investigate heart development and disease, and pushed the boundaries of what can be achieved with these versatile cells. In 2008, she became Chair of Developmental Biology at Leiden University Medical Centre, where she has refined and advanced in vitro models of the heart and now harnesses their clinical potential to screen drugs and personalise treatments for patients with various types of heart disease. Christine has become integral to the stem cell community by promoting cross-disciplinary research and serving on several Ethical Councils, Scientific Advisory Boards and Editorial Boards. Her influence in the field of stem cell research led her to become the president of International Society for Stem Cell Research in 2020, and she has won numerous awards, including the Hans Bloemendal Medal 2014 for innovative interdisciplinary research, with Gordon Keller, the prestigious Lefoulon-Delalande Prize 2021 and the International Society for Stem Cell Research (ISSCR) Public Service Award 2023. In this interview, Christine shares her career trajectory, how disease modelling is shifting towards advanced in vitro systems and what challenges the field has yet to overcome.
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The EHA Research Roadmap: Hematopoietic Stem Cells and Allotransplantation. Hemasphere 2022; 6:e0714. [PMID: 35509429 PMCID: PMC9061153 DOI: 10.1097/hs9.0000000000000714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/30/2022] [Indexed: 11/27/2022] Open
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Mutation in the CCAL1 locus accounts for bidirectional process of human subchondral bone turnover and cartilage mineralization. Rheumatology (Oxford) 2022; 62:360-372. [PMID: 35412619 PMCID: PMC9788812 DOI: 10.1093/rheumatology/keac232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/11/2022] [Accepted: 03/25/2022] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES To study the mechanism by which the readthrough mutation in TNFRSF11B, encoding osteoprotegerin (OPG) with additional 19 amino acids at its C-terminus (OPG-XL), causes the characteristic bidirectional phenotype of subchondral bone turnover accompanied by cartilage mineralization in chondrocalcinosis patients. METHODS OPG-XL was studied by human induced pluripotent stem cells expressing OPG-XL and two isogenic CRISPR/Cas9-corrected controls in cartilage and bone organoids. Osteoclastogenesis was studied with monocytes from OPG-XL carriers and matched healthy controls followed by gene expression characterization. Dual energy X-ray absorptiometry scans and MRI analyses were used to characterize the phenotype of carriers and non-carriers of the mutation. RESULTS Human OPG-XL carriers relative to sex- and age-matched controls showed, after an initial delay, large active osteoclasts with high number of nuclei. By employing hiPSCs expressing OPG-XL and isogenic CRISPR/Cas9-corrected controls to established cartilage and bone organoids, we demonstrated that expression of OPG-XL resulted in excessive fibrosis in cartilage and high mineralization in bone accompanied by marked downregulation of MGP, encoding matrix Gla protein, and upregulation of DIO2, encoding type 2 deiodinase, gene expression, respectively. CONCLUSIONS The readthrough mutation at CCAL1 locus in TNFRSF11B identifies an unknown role for OPG-XL in subchondral bone turnover and cartilage mineralization in humans via DIO2 and MGP functions. Previously, OPG-XL was shown to affect binding between RANKL and heparan sulphate (HS) resulting in loss of immobilized OPG-XL. Therefore, effects may be triggered by deficiency in the immobilization of OPG-XL Since the characteristic bidirectional pathophysiology of articular cartilage calcification accompanied by low subchondral bone mineralization is also a hallmark of OA pathophysiology, our results are likely extrapolated to common arthropathies.
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Microphysiological stem cell models of the human heart. Mater Today Bio 2022; 14:100259. [PMID: 35514437 PMCID: PMC9062349 DOI: 10.1016/j.mtbio.2022.100259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/08/2022] [Accepted: 04/10/2022] [Indexed: 11/10/2022] Open
Abstract
Models of heart disease and drug responses are increasingly based on human pluripotent stem cells (hPSCs) since their ability to capture human heart (dys-)function is often better than animal models. Simple monolayer cultures of hPSC-derived cardiomyocytes, however, have shortcomings. Some of these can be overcome using more complex, multi cell-type models in 3D. Here we review modalities that address this, describe efforts to tailor readouts and sensors for monitoring tissue- and cell physiology (exogenously and in situ) and discuss perspectives for implementation in industry and academia.
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Extraordinary challenge, extraordinary achievement: 2020-2021 year in review. Stem Cell Reports 2021; 16:1391-1393. [PMID: 34107242 PMCID: PMC8185985 DOI: 10.1016/j.stemcr.2021.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Abstract
Organs-on-chips (OoCs), also known as microphysiological systems or 'tissue chips' (the terms are synonymous), have attracted substantial interest in recent years owing to their potential to be informative at multiple stages of the drug discovery and development process. These innovative devices could provide insights into normal human organ function and disease pathophysiology, as well as more accurately predict the safety and efficacy of investigational drugs in humans. Therefore, they are likely to become useful additions to traditional preclinical cell culture methods and in vivo animal studies in the near term, and in some cases replacements for them in the longer term. In the past decade, the OoC field has seen dramatic advances in the sophistication of biology and engineering, in the demonstration of physiological relevance and in the range of applications. These advances have also revealed new challenges and opportunities, and expertise from multiple biomedical and engineering fields will be needed to fully realize the promise of OoCs for fundamental and translational applications. This Review provides a snapshot of this fast-evolving technology, discusses current applications and caveats for their implementation, and offers suggestions for directions in the next decade.
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Monitoring Undifferentiated and Potentially Malignant Human Pluripotent Stem Cells for Clinical Applications. J Comp Pathol 2020. [DOI: 10.1016/j.jcpa.2019.10.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Building blocks for a European Organ-on-Chip roadmap. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2019; 36:481-492. [PMID: 31329263 DOI: 10.14573/altex.1905221] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 06/27/2019] [Indexed: 11/23/2022]
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Activation of both transforming growth factor-β and bone morphogenetic protein signalling pathways upon traumatic brain injury restrains pro-inflammatory and boosts tissue reparatory responses of reactive astrocytes and microglia. Brain Commun 2019; 1:fcz028. [PMID: 32954268 PMCID: PMC7425383 DOI: 10.1093/braincomms/fcz028] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/24/2019] [Accepted: 10/07/2019] [Indexed: 02/06/2023] Open
Abstract
Various ligands and receptors of the transforming growth factor-β superfamily have been found upregulated following traumatic brain injury; however, the role of this signalling system in brain injury pathophysiology is not fully characterized. To address this, we utilized an acute stab wound brain injury model to demonstrate that hallmarks of transforming growth factor-β superfamily system activation, such as levels of phosphorylated Smads, ligands and target genes for both transforming growth factor-β and bone morphogenetic protein pathways, were upregulated within injured tissues. Using a bone morphogenetic protein-responsive reporter mouse model, we showed that activation of the bone morphogenetic protein signalling pathway involves primarily astrocytes that demarcate the wound area. Insights regarding the potential role of transforming growth factor-β superfamily activation in glia cells within the injured tissues were obtained indirectly by treating purified reactive astrocytes and microglia with bone morphogenetic protein-4 or transforming growth factor-β1 and characterizing changes in their transcriptional profiles. Astrocytes responded to both ligands with considerably overlapping profiles, whereas, microglia responded selectively to transforming growth factor-β1. Novel pathways, crucial for repair of tissue-injury and blood-brain barrier, such as activation of cholesterol biosynthesis and transport, production of axonal guidance and extracellular matrix components were upregulated by transforming growth factor-β1 and/or bone morphogenetic protein-4 in astrocytes. Moreover, both ligands in astrocytes and transforming growth factor-β1 in microglia shifted the phenotype of reactive glia cells towards the anti-inflammatory and tissue reparatory 'A2'-like and 'M0/M2'-like phenotypes, respectively. Increased expression of selected key components of the in vitro modulated pathways and markers of 'A2'-like astrocytes was confirmed within the wound area, suggesting that these processes could also be modulated in situ by the integrated action of transforming growth factor-β and/or bone morphogenetic protein-mediated signalling. Collectively, our study provides a comprehensive comparative analysis of transforming growth factor-β superfamily signalling in reactive astrocytes and microglia and points towards a crucial role of both transforming growth factor-β and bone morphogenetic protein pathways in modulating the inflammatory and brain injury reparatory functions of activated glia cells.
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Simultaneous measurement of contraction, voltage and calcium in HIPSC-CMS for the detection of inotropic effects under blinded conditions. J Pharmacol Toxicol Methods 2019. [DOI: 10.1016/j.vascn.2019.05.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
AIM This paper outlines the transformation of youth mental health services in Edmonton, Alberta, a large city in Western Canada. We describe the processes and challenges involved in restructuring how services and care are delivered to youth (11-25 years old) with mental health needs based on the objectives of the pan-Canadian ACCESS Open Minds network. METHODS We provide a narrative review of how youth mental health services have developed since our engagement with the ACCESS Open Minds initiative, based on its five central objectives of early identification, rapid access, appropriate care, continuity of care, and youth and family engagement. RESULTS Building on an initial community mapping exercise, a service network has been developed; teams that were previously age-oriented have been integrated together to seamlessly cover the age 11 to 25 range; early identification has thus far focused on high-school populations; and an actual drop-in space facilitates rapid access and linkages to appropriate care within the 30-day benchmark. CONCLUSIONS Initial aspects of the transformation have relied on restructuring and partnerships that have generated early successes. However, further transformation over the longer term will depend on data demonstrating how this has impacted clinical outcomes and service utilization. Ultimately, sustainability in a large urban centre will likely involve scaling up to a network of similar services to cover the entire population of the city.
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The MicroRNA-371 Family as Plasma Biomarkers for Monitoring Undifferentiated and Potentially Malignant Human Pluripotent Stem Cells in Teratoma Assays. Stem Cell Reports 2018; 11:1493-1505. [PMID: 30503260 PMCID: PMC6294243 DOI: 10.1016/j.stemcr.2018.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 11/01/2018] [Accepted: 11/01/2018] [Indexed: 01/09/2023] Open
Abstract
Predicting developmental potency and risk of posttransplantation tumor formation by human pluripotent stem cells (hPSCs) and their derivatives largely rely on classical histological analysis of teratomas. Here, we investigated whether an assay based on microRNAs (miRNA) in blood plasma is able to detect potentially malignant elements. Several hPSCs and human malignant germ cell tumor (hGCT) lines were investigated in vitro and in vivo after mouse xenografting. The multiple conventional hPSC lines generated mature teratomas, while xenografts from induced hPSCs (hiPSCs) with reactivated reprogramming transgenes and hGCT lines contained undifferentiated and potentially malignant components. The presence of these elements was reflected in the mRNA and miRNA profiles of the xenografts with OCT3/4 mRNA and the miR-371 and miR-302 families readily detectable. miR-371 family members were also identified in mouse plasma faithfully reporting undifferentiated elements in the xenografts. This study demonstrated that undifferentiated and potentially malignant cells could be detected in vivo.
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The Next Chapter for Stem Cell Reports. Stem Cell Reports 2018; 11:1303-1304. [PMID: 30540956 PMCID: PMC6294170 DOI: 10.1016/j.stemcr.2018.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Regenerative medicine funding policies in Europe and The Netherlands. NPJ Regen Med 2018; 2:1. [PMID: 29302338 PMCID: PMC5677946 DOI: 10.1038/s41536-016-0006-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 11/15/2016] [Indexed: 11/09/2022] Open
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Z-disc protein CHAPb induces cardiomyopathy and contractile dysfunction in the postnatal heart. PLoS One 2017; 12:e0189139. [PMID: 29206857 PMCID: PMC5716575 DOI: 10.1371/journal.pone.0189139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 11/20/2017] [Indexed: 12/17/2022] Open
Abstract
Aims The Z-disc is a crucial structure of the sarcomere and is implicated in mechanosensation/transduction. Dysregulation of Z-disc proteins often result in cardiomyopathy. We have previously shown that the Z-disc protein Cytoskeletal Heart-enriched Actin-associated Protein (CHAP) is essential for cardiac and skeletal muscle development. Furthermore, the CHAP gene has been associated with atrial fibrillation in humans. Here, we studied the misregulated expression of CHAP isoforms in heart disease. Methods and results Mice that underwent transverse aortic constriction and calcineurin transgenic (Tg) mice, both models of experimental heart failure, displayed a significant increase in cardiac expression of fetal isoform CHAPb. To investigate whether increased expression of CHAPb postnatally is sufficient to induce cardiomyopathy, we generated CHAPb Tg mice under the control of the cardiac-specific αMHC promoter. CHAPb Tg mice displayed cardiac hypertrophy, interstitial fibrosis and enlargement of the left atrium at three months, which was more pronounced at the age of six months. Hypertrophy and fibrosis were confirmed by evidence of activation of the hypertrophic gene program (Nppa, Nppb, Myh7) and increased collagen expression, respectively. Connexin40 and 43 were downregulated in the left atrium, which was associated with delayed atrioventricular conduction. Tg hearts displayed both systolic and diastolic dysfunction partly caused by impaired sarcomere function evident from a reduced force generating capacity of single cardiomyocytes. This co-incided with activation of the actin signalling pathway leading to the formation of stress fibers. Conclusion This study demonstrated that the fetal isoform CHAPb initiates progression towards cardiac hypertrophy, which is accompanied by delayed atrioventricular conduction and diastolic dysfunction. Moreover, CHAP may be a novel therapeutic target or candidate gene for screening in cardiomyopathies and atrial fibrillation.
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Abstract
This SnapShot presents a timeline of key advances in directed differentiation and disease modeling using human pluripotent stem cells. The selected papers are color-coded for different systems and show progress in the field, from making disease- and tissue-specific hiPSC derivatives to the development of disease models for drug screening and therapeutics and the generation of complex systems that mimic tissue architecture and self-organized structures. To view this SnapShot, open or download the PDF.
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Organ-on-Chip: A synthetic mimic for human myocardium. J Pharmacol Toxicol Methods 2016. [DOI: 10.1016/j.vascn.2016.02.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Improved functional maturation of human induced pluripotent stem cell (hiPSC) derived ventricular cardiomyocytes in vitro: Multi-electrode array (MEA) based electrophysiological characterization. J Pharmacol Toxicol Methods 2016. [DOI: 10.1016/j.vascn.2016.02.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cytostretch, an Organ-on-Chip Platform. MICROMACHINES 2016; 7:mi7070120. [PMID: 30404293 PMCID: PMC6189941 DOI: 10.3390/mi7070120] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/30/2016] [Accepted: 07/07/2016] [Indexed: 12/31/2022]
Abstract
Organ-on-Chips (OOCs) are micro-fabricated devices which are used to culture cells in order to mimic functional units of human organs. The devices are designed to simulate the physiological environment of tissues in vivo. Cells in some types of OOCs can be stimulated in situ by electrical and/or mechanical actuators. These actuations can mimic physiological conditions in real tissue and may include fluid or air flow, or cyclic stretch and strain as they occur in the lung and heart. These conditions similarly affect cultured cells and may influence their ability to respond appropriately to physiological or pathological stimuli. To date, most focus has been on devices specifically designed to culture just one functional unit of a specific organ: lung alveoli, kidney nephrons or blood vessels, for example. In contrast, the modular Cytostretch membrane platform described here allows OOCs to be customized to different OOC applications. The platform utilizes silicon-based micro-fabrication techniques that allow low-cost, high-volume manufacturing. We describe the platform concept and its modules developed to date. Membrane variants include membranes with (i) through-membrane pores that allow biological signaling molecules to pass between two different tissue compartments; (ii) a stretchable micro-electrode array for electrical monitoring and stimulation; (iii) micro-patterning to promote cell alignment; and (iv) strain gauges to measure changes in substrate stress. This paper presents the fabrication and the proof of functionality for each module of the Cytostretch membrane. The assessment of each additional module demonstrate that a wide range of OOCs can be achieved.
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BMP and Hedgehog Regulate Distinct AGM Hematopoietic Stem Cells Ex Vivo. Stem Cell Reports 2016; 6:383-95. [PMID: 26923823 PMCID: PMC4788785 DOI: 10.1016/j.stemcr.2016.01.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022] Open
Abstract
Hematopoietic stem cells (HSC), the self-renewing cells of the adult blood differentiation hierarchy, are generated during embryonic stages. The first HSCs are produced in the aorta-gonad-mesonephros (AGM) region of the embryo through endothelial to a hematopoietic transition. BMP4 and Hedgehog affect their production and expansion, but it is unknown whether they act to affect the same HSCs. In this study using the BRE GFP reporter mouse strain that identifies BMP/Smad-activated cells, we find that the AGM harbors two types of adult-repopulating HSCs upon explant culture: One type is BMP-activated and the other is a non-BMP-activated HSC type that is indirectly controlled by Hedgehog signaling through the VEGF pathway. Transcriptomic analyses demonstrate that the two HSC types express distinct but overlapping genetic programs. These results revealing the bifurcation in HSC types at early embryonic stages in the AGM explant model suggest that their development is dependent upon the signaling molecules in the microenvironment. AGM explants contain two HSC types, BMP-activated and non-BMP-activated Non-BMP-activated HSCs are dependent on Hedgehog/VEGF Changes in the microenvironment ex vivo contribute to novel HSC composition
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Assessing Pluripotency of Human Pluripotent Stem Cells: Challenges for the Pathologist. J Comp Pathol 2016. [DOI: 10.1016/j.jcpa.2015.10.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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BMP-SMAD Signaling Regulates Lineage Priming, but Is Dispensable for Self-Renewal in Mouse Embryonic Stem Cells. Stem Cell Reports 2015; 6:85-94. [PMID: 26711875 PMCID: PMC4720007 DOI: 10.1016/j.stemcr.2015.11.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 01/10/2023] Open
Abstract
Naive mouse embryonic stem cells (mESCs) are in a metastable state and fluctuate between inner cell mass- and epiblast-like phenotypes. Here, we show transient activation of the BMP-SMAD signaling pathway in mESCs containing a BMP-SMAD responsive reporter transgene. Activation of the BMP-SMAD reporter transgene in naive mESCs correlated with lower levels of genomic DNA methylation, high expression of 5-methylcytosine hydroxylases Tet1/2 and low levels of DNA methyltransferases Dnmt3a/b. Moreover, naive mESCs, in which the BMP-SMAD reporter transgene was activated, showed higher resistance to differentiation. Using double Smad1;Smad5 knockout mESCs, we showed that BMP-SMAD signaling is dispensable for self-renewal in both naive and ground state. These mutant mESCs were still pluripotent, but they exhibited higher levels of DNA methylation than their wild-type counterparts and had a higher propensity to differentiate. We showed that BMP-SMAD signaling modulates lineage priming in mESCs, by transiently regulating the enzymatic machinery responsible for DNA methylation. BMP-SMAD signaling in mESCs is more prominent in naive than ground state BMP-SMAD signaling is dispensable for pluripotency in mESCs BMP-SMAD signaling facilitates lineage priming in mESCs BMP-SMAD signaling regulates Dnmt3b and hence levels of DNA methylation
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International coordination of large-scale human induced pluripotent stem cell initiatives: Wellcome Trust and ISSCR workshops white paper. Stem Cell Reports 2015; 3:931-9. [PMID: 25496616 PMCID: PMC4263998 DOI: 10.1016/j.stemcr.2014.11.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
There is growing recognition of the potential value of human induced pluripotent stem cells (hiPSC) for understanding disease and identifying drugs targets. This has been reflected in the establishment of multiple large-scale hiPSC initiatives worldwide. Representatives of these met recently at a workshop supported by the Welcome Trust in the UK and in a focus session at the 2014 ISSCR annual meeting in Vancouver. The purpose was to discuss strategies for making thousands of hiPSC lines widely available with as few restrictions as possible while retaining financial viability and donor privacy. The outcome of these discussions is described here.
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A panel of nine cerebrospinal fluid biomarkers may identify patients with atypical parkinsonian syndromes. J Neurol Neurosurg Psychiatry 2015; 86:1240-7. [PMID: 25589779 PMCID: PMC4564944 DOI: 10.1136/jnnp-2014-309562] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/15/2014] [Indexed: 11/04/2022]
Abstract
BACKGROUND Patients presenting with parkinsonian syndromes share many clinical features, which can make diagnosis difficult. This is important as atypical parkinsonian syndromes (APSs) such as progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and corticobasal syndrome (CBS) carry a poor prognosis, compared with patients with Parkinson's disease (PD). In addition, there is overlap between APS and dementia diseases, such as Alzheimer's disease (AD) and frontotemporal dementia (FTD). OBJECTIVE To use a panel of cerebrospinal fluid (CSF) biomarkers to differentiate patients with APS from PD and dementia. METHODS A prospective cohort of 160 patients and 30 control participants were recruited from a single specialist centre. Patients were clinically diagnosed according to current consensus criteria. CSF samples were obtained from patients with clinical diagnoses of PD (n=31), PSP (n=33), CBS (n=14), MSA (n=31), AD (n=26) and FTD (n=16). Healthy, elderly participants (n=30) were included as controls. Total τ (t-τ), phosphorylated τ (p-τ), β-amyloid 1-42 (Aβ42), neurofilament light chain (NFL), α-synuclein (α-syn), amyloid precursor protein soluble metabolites α and β (soluble amyloid precursor protein (sAPP)α, sAPPβ) and two neuroinflammatory markers (monocyte chemoattractant protein-1 and YKL-40) were measured in CSF. A reverse stepwise regression analysis and the false discovery rate procedure were used. RESULTS CSF NFL (p<0.001), sAPPα (p<0.001) and a-syn (p=0.003) independently predicted diagnosis of PD versus APS. Together, these nine biomarkers could differentiate patients with PD from APS with an area under the curve of 0.95 and subtypes of APS from one another. There was good discriminatory power between parkinsonian groups, dementia disorders and healthy controls. CONCLUSIONS A panel of nine CSF biomarkers was able to differentiate APS from patients with PD and dementia. This may have important clinical utility in improving diagnostic accuracy, allowing better prognostication and earlier access to potential disease-modifying therapies.
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Corrigendum: BMP signalling differentially regulates distinct haematopoietic stem cell types. Nat Commun 2015; 6:8793. [PMID: 26510935 PMCID: PMC7188459 DOI: 10.1038/ncomms9793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Points to consider in the development of seed stocks of pluripotent stem cells for clinical applications: International Stem Cell Banking Initiative (ISCBI). Regen Med 2015; 10:1-44. [PMID: 25675265 DOI: 10.2217/rme.14.93] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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Transcribed enhancers lead waves of coordinated transcription in transitioning mammalian cells. Science 2015; 347:1010-4. [PMID: 25678556 PMCID: PMC4681433 DOI: 10.1126/science.1259418] [Citation(s) in RCA: 405] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Although it is generally accepted that cellular differentiation requires changes to transcriptional networks, dynamic regulation of promoters and enhancers at specific sets of genes has not been previously studied en masse. Exploiting the fact that active promoters and enhancers are transcribed, we simultaneously measured their activity in 19 human and 14 mouse time courses covering a wide range of cell types and biological stimuli. Enhancer RNAs, then messenger RNAs encoding transcription factors, dominated the earliest responses. Binding sites for key lineage transcription factors were simultaneously overrepresented in enhancers and promoters active in each cellular system. Our data support a highly generalizable model in which enhancer transcription is the earliest event in successive waves of transcriptional change during cellular differentiation or activation.
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Modelling sarcomeric cardiomyopathies in the dish: from human heart samples to iPSC cardiomyocytes. Cardiovasc Res 2015; 105:424-38. [PMID: 25618410 PMCID: PMC4349163 DOI: 10.1093/cvr/cvv017] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
One of the obstacles to a better understanding of the pathogenesis of human cardiomyopathies has been poor availability of heart-tissue samples at early stages of disease development. This has possibly changed by the advent of patient-derived induced pluripotent stem cell (hiPSC) from which cardiomyocytes can be derived in vitro. The main promise of hiPSC technology is that by capturing the effects of thousands of individual gene variants, the phenotype of differentiated derivatives of these cells will provide more information on a particular disease than simple genotyping. This article summarizes what is known about the ‘human cardiomyopathy or heart failure phenotype in vitro’, which constitutes the reference for modelling sarcomeric cardiomyopathies in hiPSC-derived cardiomyocytes. The current techniques for hiPSC generation and cardiac myocyte differentiation are briefly reviewed and the few published reports of hiPSC models of sarcomeric cardiomyopathies described. A discussion of promises and challenges of hiPSC-modelling of sarcomeric cardiomyopathies and individualized approaches is followed by a number of questions that, in the view of the authors, need to be answered before the true potential of this technology can be evaluated.
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BMP4 promotes EMT and mesodermal commitment in human embryonic stem cells via SLUG and MSX2. Stem Cells 2014; 32:636-48. [PMID: 24549638 DOI: 10.1002/stem.1592] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 10/08/2013] [Accepted: 10/12/2013] [Indexed: 01/05/2023]
Abstract
Bone morphogenetic proteins (BMPs) initiate differentiation in human embryonic stem cells (hESCs) but the exact mechanisms have not been fully elucidated. We demonstrate here that SLUG and MSX2, transcription factors involved in epithelial-mesenchymal transitions, essential features of gastrulation in development and tumor progression, are important mediators of BMP4-induced differentiation in hESCs. Phosphorylated Smad1/5/8 colocalized with the SLUG protein at the edges of hESC colonies where differentiation takes place. The upregulation of the BMP target SLUG was direct as shown by the binding of phosphorylated Smad1/5/8 to its promoter, which interrupted the formation of adhesion proteins, resulting in migration. Knockdown of SLUG by short hairpin RNA blocked these changes, confirming an important role for SLUG in BMP-mediated mesodermal differentiation. Furthermore, BMP4-induced MSX2 expression leads to mesoderm formation and then preferential differentiation toward the cardiovascular lineage.
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ENDOGLIN is dispensable for vasculogenesis, but required for vascular endothelial growth factor-induced angiogenesis. PLoS One 2014; 9:e86273. [PMID: 24489709 PMCID: PMC3904881 DOI: 10.1371/journal.pone.0086273] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 12/10/2013] [Indexed: 01/10/2023] Open
Abstract
ENDOGLIN (ENG) is a co-receptor for transforming growth factor-β (TGF-β) family members that is highly expressed in endothelial cells and has a critical function in the development of the vascular system. Mutations in Eng are associated with the vascular disease known as hereditary hemorrhagic telangiectasia type l. Using mouse embryonic stem cells we observed that angiogenic factors, including vascular endothelial growth factor (VEGF), induce vasculogenesis in embryoid bodies even when Eng deficient cells or cells depleted of Eng using shRNA are used. However, ENG is required for the stem cell-derived endothelial cells to organize effectively into tubular structures. Consistent with this finding, fetal metatarsals isolated from E17.5 Eng heterozygous mouse embryos showed reduced VEGF-induced vascular network formation. Moreover, shRNA-mediated depletion and pharmacological inhibition of ENG in human umbilical vein cells mitigated VEGF-induced angiogenesis. In summary, we demonstrate that ENG is required for efficient VEGF-induced angiogenesis.
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Abstract
Understanding the molecular basis of many cardiac diseases has been hampered by the lack of appropriate in vitro cell culture models that accurately reflect the human disease phenotypes. In the past few years, remarkable advances in stem cell biology have made possible this long-standing ambition-the generation of human and even patient-specific cellular models of diseases. Combined with other novel technologies in the fields of human genetics, tissue engineering, and gene-targeted manipulation, disease modeling with pluripotent stem cells has the promise to influence modern cardiovascular medicine on several fronts: molecular understanding of pathological mechanisms, early diagnosis, drug development, and effective treatment.
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Regulation of stem cell therapies under attack in Europe: for whom the bell tolls. EMBO J 2013; 32:1489-95. [PMID: 23644381 PMCID: PMC3671253 DOI: 10.1038/emboj.2013.114] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 04/29/2013] [Indexed: 02/02/2023] Open
Abstract
At the time of writing, the Italian Parliament is debating a new law that would make it legal to practice an unproven stem cell treatment in public hospitals. The treatment, offered by a private non-medical organization, may not be safe, lacks a rationale, and violates current national laws and European regulations. This case raises multiple concerns, most prominently the urgent need to protect patients who are severely ill, exposed to significant risks, and vulnerable to exploitation. The scientific community must consider the context-social, financial, medical, legal-in which stem cell science is currently situated and the need for stringent regulation. Additional concerns are emerging. These emanate from the novel climate, created within science itself, and stem cell science in particular, by the currently prevailing model of 'translational medicine'. Only rigorous science and rigorous regulation can ensure translation of science into effective therapies rather than into ineffective market products, and mark, at the same time, the sharp distinction between the striving for new therapies and the deceit of patients.
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AVOIDING UNPLANNED HOSPITAL ADMISSIONS IN PATIENTS WITH NEUROMUSCULAR DISEASES: A REGIONAL COLLABORATIVE AUDIT OF HOSPITAL ADMISSIONS. J Neurol Psychiatry 2012. [DOI: 10.1136/jnnp-2012-304200a.88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Genetically Engineered Mesenchymal Stem Cells Influence Gene Expression in Donor Cardiomyocytes and the Recipient Heart. ACTA ACUST UNITED AC 2012; S1. [PMID: 23125947 DOI: 10.4172/2157-7633.s1-005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
AIMS: Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) or mesenchymal stem cells (MSCs) facilitate post-infarct recovery, but the potential benefit of combination therapy using MSCs and hESC-CMs has not been examined. Our objective was to define the gene expression changes in donor and host-derived cells that are induced in vivo after co-transplantation of cardiomyocytes with and without mesenchymal stem cells expressing the prosurvival gene heme oxygenase 1. METHODS AND RESULTS: Human MSCs were engineered to over-express heme oxygenase-1 (HO-1) following lentiviral vector-mediated transduction. Athymic nude rats were subjected to myocardial infarction and received hESC-CMs alone, hESC-CMs plus human MSCs, hESC-CMs plus MSCs overexpressing HO-1, or saline. Real time PCR identified gene expression changes. Cardiac function was assessed by angiography. Co-transplantation of unmodified MSCs plus hESC-CMs elevated CXCR4, HGF, and IGF expression over levels induced by injection of hESC-derived cardiomyocytes alone. In animals co-transplanted with MSC over-expressing HO-1, the expression of these genes was further elevated. Gene expression levels of VEGF, TGF-β, CCL2, SMAD7, STAT3 and cardiomyocyte transcription factors were highest in the HO-1 MSC plus hESC-CM group at 30 days. Human CD31+, CD34+, isl-1+, NXK2.5 and c-kit+ transcripts were elevated. Rodent genes encoding NKX2.5, troponin T and CD31 were elevated and cell cycle genes were induced. Ejection fraction improved by six to seven percent. CONCLUSIONS: Co-administration of HO-1 MSCs plus hESC-CMs increased expression of pro-survival and angiogenesis-promoting genes in human cells and transcripts of cardiac and endothelial cell markers in rodent cells, consistent with activation of tissue repair in both transplanted hESC-CMs and the host heart.
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Cytoskeletal heart-enriched actin-associated protein (CHAP) is expressed in striated and smooth muscle cells in chick and mouse during embryonic and adult stages. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2012; 55:649-55. [PMID: 21948713 DOI: 10.1387/ijdb.103207wv] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We recently identified a new Z-disc protein, CHAP (Cytoskeletal Heart-enriched Actin-associated Protein), which is expressed in striated muscle and plays an important role during embryonic muscle development in mouse and zebrafish. Here, we confirm and further extend these findings by (i) the identification and characterization of the CHAP orthologue in chick and (ii) providing a detailed analysis of CHAP expression in mouse during embryonic and adult stages. Chick CHAP contains a PDZ domain and a nuclear localization signal, resembling the human and mouse CHAPa. CHAP is expressed in the developing heart and somites, as well as muscle precursors of the limb buds in mouse and chick embryos. CHAP expression in heart and skeletal muscle is maintained in adult mice, both in slow and fast muscle fibers. Moreover, besides expression in striated muscle, we demonstrate that CHAP is expressed in smooth muscle cells of aorta, carotid and coronary arteries in adult mice, but not during embryonic development.
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Proteomic analysis of stem cell differentiation and early development. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a008177. [PMID: 22317846 DOI: 10.1101/cshperspect.a008177] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genomics methodologies have advanced to the extent that it is now possible to interrogate the gene expression in a single cell but proteomics has traditionally lagged behind and required much greater cellular input and was not quantitative. Coupling protein with gene expression data is essential for understanding how cell behavior is regulated. Advances primarily in mass spectrometry have, however, greatly improved the sensitivity of proteomics methods over the last decade and the outcome of proteomic analyses can now also be quantified. Nevertheless, it is still difficult to obtain sufficient tissue from staged mammalian embryos to combine proteomic and genomic analyses. Recent developments in pluripotent stem cell biology have in part addressed this issue by providing surrogate scalable cell systems in which early developmental events can be modeled. Here we present an overview of current proteomics methodologies and the kind of information this can provide on the biology of human and mouse pluripotent stem cells.
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Activation of the canonical bone morphogenetic protein (BMP) pathway during lung morphogenesis and adult lung tissue repair. PLoS One 2012; 7:e41460. [PMID: 22916109 PMCID: PMC3423416 DOI: 10.1371/journal.pone.0041460] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 06/22/2012] [Indexed: 02/05/2023] Open
Abstract
Signaling by Bone Morphogenetic Proteins (BMP) has been implicated in early lung development, adult lung homeostasis and tissue-injury repair. However, the precise mechanism of action and the spatio-temporal pattern of BMP-signaling during these processes remains inadequately described. To address this, we have utilized a transgenic line harboring a BMP-responsive eGFP-reporter allele (BRE-eGFP) to construct the first detailed spatiotemporal map of canonical BMP-pathway activation during lung development, homeostasis and adult-lung injury repair. We demonstrate that during the pseudoglandular stage, when branching morphogenesis progresses in the developing lung, canonical BMP-pathway is active mainly in the vascular network and the sub-epithelial smooth muscle layer of the proximal airways. Activation of the BMP-pathway becomes evident in epithelial compartments only after embryonic day (E) 14.5 primarily in cells negative for epithelial-lineage markers, located in the proximal portion of the airway-tree, clusters adjacent to neuro-epithelial-bodies (NEBs) and in a substantial portion of alveolar epithelial cells. The pathway becomes activated in isolated E12.5 mesenchyme-free distal epithelial buds cultured in Matrigel suggesting that absence of reporter activity in these regions stems from a dynamic cross-talk between endoderm and mesenchyme. Epithelial cells with activated BMP-pathway are enriched in progenitors capable of forming colonies in three-dimensional Matrigel cultures.As lung morphogenesis approaches completion, eGFP-expression declines and in adult lung its expression is barely detectable. However, upon tissue-injury, either with naphthalene or bleomycin, the canonical BMP-pathways is re-activated, in bronchial or alveolar epithelial cells respectively, in a manner reminiscent to early lung development and in tissue areas where reparatory progenitor cells reside. Our studies illustrate the dynamic activation of canonical BMP-pathway during lung development and adult lung tissue-repair and highlight its involvement in two important processes, namely, the early development of the pulmonary vasculature and the management of epithelial progenitor pools both during lung development and repair of adult lung tissue-injury.
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Shedding new light on the mechanism underlying stem cell therapy for the heart. Mol Ther 2011; 19:1186-8. [PMID: 21720378 DOI: 10.1038/mt.2011.117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Abstract P028: The Effect of Cotransplantation of Human Embryonic Stem Cell--Derived Cardiomyocytes and Mesenchymal Stem Cells on Ventricular Function and Remodeling After Myocardial Infarction in Nude Rats. Circ Res 2011. [DOI: 10.1161/res.109.suppl_1.ap028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We determined whether co-transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and mesenchymal stem cells (MSCs) had additive effects on left ventricular (LV) function and remodeling compared with hESC-CMs treatment alone in a rat myocardial infarction model. One week after myocardial infarction induced by left coronary ligation, nude rats received hESC-CMs (n=15), hESC-CMs + MSCs (n=16), hESC-CMs + MSCs transduced to over-express hemeoxygenase 1(HO-1) (n=14), or saline (n=19). At 4 weeks after treatment, LV function was assessed by left ventriculography, echocardiography and Millar catheter. Some hearts were processed for histology. The LV ejection fraction (LVEF) in sham noninfarcted hearts was 78.1±1.8% (n=5) in the nude rat model. LVEF in the 3 cell treated groups (hESC-CMs: 67.6±1.4%; hESC-CMs + MSCs: 67.2±1.6%; and hESC-CMs + MSCs with HO-1: 66.3±1.7%) were comparable, and significantly higher than in the saline group (60.6±1.2%, n=19; p=0.0022). There was a trend for less left ventricular akinesis and dyskinesis (expressed as % of LV circumference) assessed by left ventriculography at 8.96±1.9% in hESC-CMs group, 8.37±1.67% in hESC-CMs + MSCs group and 4.57±1% in hESC-CMs + MSCs with HO-1 group compared to 10.73±1.76% in the control group (p=0.056). There was a nonsignificant trend for LV fractional shortening assessed by echocardiography to be greater in the 3 cell groups (32.1±3.9% in hESC-CMs; 30.2±2% in hESC-CMs + MSCs; 31.0±1.9% in hESC-CMs + MSCs with HO-1) compared to 24.8±2.2% in the saline group (p=0.18). Expansion index reflecting thinning and dilatation of the infarct was significantly worse in the control group at 0.71±0.05 versus the other 3 groups at 0.32±0.05 (p=0.0039). Thus, cell therapy by hESC-CMs alone or combination transplantation of hESC-CMs and MSCs (with or without HO-1) significantly improved LV function assessed by left ventriculography and reduced expansion index. However, co-transplantation of hESC-CMs and MSCs did not provide better functional improvement compared with hESC-CMs treatment alone after left coronary artery occlusion in nude rats over a period of 4 weeks, suggesting that there may be a ceiling effect above which LV function can not further improve after cell therapy.
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Screening ethnically diverse human embryonic stem cells identifies a chromosome 20 minimal amplicon conferring growth advantage. Nat Biotechnol 2011; 29:1132-44. [PMID: 22119741 PMCID: PMC3454460 DOI: 10.1038/nbt.2051] [Citation(s) in RCA: 405] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 10/26/2011] [Indexed: 02/07/2023]
Abstract
The International Stem Cell Initiative analyzed 125 human embryonic stem (ES) cell lines and 11 induced pluripotent stem (iPS) cell lines, from 38 laboratories worldwide, for genetic changes occurring during culture. Most lines were analyzed at an early and late passage. Single-nucleotide polymorphism (SNP) analysis revealed that they included representatives of most major ethnic groups. Most lines remained karyotypically normal, but there was a progressive tendency to acquire changes on prolonged culture, commonly affecting chromosomes 1, 12, 17 and 20. DNA methylation patterns changed haphazardly with no link to time in culture. Structural variants, determined from the SNP arrays, also appeared sporadically. No common variants related to culture were observed on chromosomes 1, 12 and 17, but a minimal amplicon in chromosome 20q11.21, including three genes expressed in human ES cells, ID1, BCL2L1 and HM13, occurred in >20% of the lines. Of these genes, BCL2L1 is a strong candidate for driving culture adaptation of ES cells.
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Abstract
TGF-β is the primary inducer of extracellular matrix proteins in scleroderma (systemic sclerosis, SSc). Previous studies indicate that in a subset of SSc fibroblasts TGF-β signaling is activated via elevated levels of activin receptor-like kinase (ALK) 1 and phosphorylated Smad1 (pSmad1). The goal of this study was to determine the role of endoglin/ALK1 in TGF-β/Smad1 signaling in SSc fibroblasts. In SSc fibroblasts, increased levels of endoglin correlated with high levels of pSmad1, collagen, and connective tissue growth factor (CCN2). Endoglin depletion via siRNA in SSc fibroblasts inhibited pSmad1 but did not affect pSmad2/3. Following endoglin depletion mRNA and protein levels of collagen and CCN2 were significantly decreased in SSc fibroblasts but remained unchanged in normal fibroblasts. ALK1 was expressed at similar levels in SSc and normal fibroblasts. Depletion of ALK1 resulted in inhibition of pSmad1 and a moderate but significant reduction of mRNA and protein levels of collagen and CCN2 in SSc fibroblasts. Furthermore, constitutively high levels of endoglin were found in complexes with ALK1 in SSc fibroblasts. Overexpression of constitutively active ALK1 (caALK1) in normal and SSc fibroblasts led to a moderate increase of collagen and CCN2. However, caALK1 potently induced endothelin 1 (ET-1) mRNA and protein levels in SSc fibroblasts. Additional experiments demonstrated that endoglin and ALK1 mediate TGF-β induction of ET-1 in SSc and normal fibroblasts. In conclusion, this study has revealed an important profibrotic role of endoglin in SSc fibroblasts. The endoglin/ALK1/Smad1 pathway could be a therapeutic target in patients with SSc if appropriately blocked.
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