| 1. |
- Anderson, JD, et al.
(författare)
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Comprehensive Proteomic Analysis of Mesenchymal Stem Cell Exosomes Reveals Modulation of Angiogenesis via Nuclear Factor-KappaB Signaling
- 2016
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 34:3, s. 601-613
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Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stem cells (MSC) are known to facilitate healing of ischemic tissue related diseases through proangiogenic secretory proteins. Recent studies further show that MSC derived exosomes function as paracrine effectors of angiogenesis, however, the identity of which components of the exosome proteome responsible for this effect remains elusive. To address this we used high-resolution isoelectric focusing coupled liquid chromatography tandem mass spectrometry, an unbiased high throughput proteomics approach to comprehensively characterize the proteinaceous contents of MSCs and MSC derived exosomes. We probed the proteome of MSCs and MSC derived exosomes from cells cultured under expansion conditions and under ischemic tissue simulated conditions to elucidate key angiogenic paracrine effectors present and potentially differentially expressed in these conditions. In total, 6,342 proteins were identified in MSCs and 1,927 proteins in MSC derived exosomes, representing to our knowledge the first time these proteomes have been probed comprehensively. Multilayered analyses identified several putative paracrine effectors of angiogenesis present in MSC exosomes and increased in expression in MSCs exposed to ischemic tissue-simulated conditions; these include platelet derived growth factor, epidermal growth factor, fibroblast growth factor, and most notably nuclear factor-kappaB (NFkB) signaling pathway proteins. NFkB signaling was identified as a key mediator of MSC exosome induced angiogenesis in endothelial cells by functional in vitro validation using a specific inhibitor. Collectively, the results of our proteomic analysis show that MSC derived exosomes contain a robust profile of angiogenic paracrine effectors, which have potential for the treatment of ischemic tissue-related diseases.
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| 2. |
- Blanchart, A, et al.
(författare)
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UHRF1 Licensed Self-Renewal of Active Adult Neural Stem Cells
- 2018
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 36:11, s. 1736-1751
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Tidskriftsartikel (refereegranskat)abstract
- Adult neurogenesis in the brain continuously seeds new neurons throughout life, but how homeostasis of adult neural stem cells (NSCs) is maintained is incompletely understood. Here, we demonstrate that the DNA methylation adapter ubiquitin-like, containing PHD and RING finger domains-1 (UHRF1) is expressed in, and regulates proliferation of, the active but not quiescent pool of adult neural progenitor cells. Mice with a neural stem cell-specific deficiency in UHRF1 exhibit a massive depletion of neurogenesis resulting in a collapse of formation of new neurons. In the absence of UHRF1, NSCs unexpectedly remain in the cell cycle but with a 17-fold increased cell cycle length due to a failure of replication phase entry caused by promoter demethylation and derepression of Cdkn1a, which encodes the cyclin-dependent kinase inhibitor p21. UHRF1 does not affect the proportion progenitor cells active within the cell cycle but among these cells, UHRF1 is critical for licensing replication re-entry. Therefore, this study shows that a UHRF1-Cdkn1a axis is essential for the control of stem cell self-renewal and neurogenesis in the adult brain.
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| 3. |
- Blank Savukinas, Ulrika, et al.
(författare)
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The Bystander Effect : Mesenchymal Stem Cell-Mediated Lung Repair
- 2016
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 34:6, s. 1437-1444
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Forskningsöversikt (refereegranskat)abstract
- Mesenchymal stem or stromal cells (MSCs), a heterogeneous subset of adult stem/progenitor cells, have surfaced as potential therapeutic units with significant clinical benefit for a wide spectrum of disease conditions, including those affecting the lung. Although MSCs carry both self-renewal and multilineage differentiation abilities, current dogma holds that MSCs mainly contribute to tissue regeneration and repair by modulating the host tissue via secreted cues. Thus, the therapeutic benefit of MSCs is thought to derive from so called bystander effects. The regenerative mechanisms employed by MSCs in the lung include modulation of the immune system as well as promotion of epithelial and endothelial repair. Apart from secreted factors, a number of recent findings suggest that MSCs engage in mitochondrial transfer and shedding of membrane vesicles as a means to enhance tissue repair following injury. Furthermore, it is becoming increasingly clear that MSCs are an integral component of epithelial lung stem cell niches. As such, MSCs play an important role in coupling information from the environment to stem and progenitor populations, such that homeostasis can be ensured even in the face of injury. It is the aim of this review to outline the major mechanisms by which MSCs contribute to lung regeneration, synthesizing recent preclinical findings with data from clinical trials and potential for future therapy
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| 4. |
- Bosman, A, et al.
(författare)
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Perturbations of heart development and function in cardiomyocytes from human embryonic stem cells with trisomy 21
- 2015
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 33:5, s. 1434-1446
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Tidskriftsartikel (refereegranskat)abstract
- Congenital heart defects (CHD) occur in approximately 50% of patients with Down syndrome (DS); the mechanisms for this occurrence however remain unknown. In order to understand how these defects evolve in early development in DS, we focused on the earliest stages of cardiogenesis to ascertain perturbations in development leading to CHD. Using a trisomy 21 (T21) sibling human embryonic stem cell (hESC) model of DS, we show that T21-hESC display many significant differences in expression of genes and cell populations associated with mesodermal, and more notably, secondary heart field (SHF) development, in particular a reduced number of ISL1+ progenitor cells. Furthermore, we provide evidence for two candidate genes located on chromosome 21, ETS2 and ERG, whose overexpression during cardiac commitment likely account for the disruption of SHF development, as revealed by downregulation or overexpression experiments. Additionally, we uncover an abnormal electrophysiological phenotype in functional T21 cardiomyocytes, a result further supported by mRNA expression data acquired using RNA-Seq. These data, in combination, revealed a cardiomyocyte-specific phenotype in T21 cardiomyocytes, likely due to the overexpression of genes such as RYR2, NCX, and L-type Ca2+ channel. These results contribute to the understanding of the mechanisms involved in the development of CHD. Stem Cells 2015;33:1434–1446
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| 5. |
- Bottcher, M, et al.
(författare)
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Mesenchymal Stromal Cells Disrupt mTOR-Signaling and Aerobic Glycolysis During T-Cell Activation
- 2016
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 34:2, s. 516-521
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Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stromal cells (MSCs) possess numerous regenerative and immune modulating functions. Transplantation across histocompatibility barriers is feasible due to their hypo-immunogenicity. MSCs have emerged as promising tools for treating graft-versus-host disease following allogeneic stem cell transplantation. It is well established that their clinical efficacy is substantially attributed to fine-tuning of T-cell responses. At the same time, increasing evidence suggests that metabolic processes control T-cell function and fate. Here, we investigated the MSCs' impact on the metabolic framework of activated T-cells. In fact, MSCs led to mitigated mTOR signaling. This phenomenon was accompanied by a weaker glycolytic response (including glucose uptake, glycolytic rate, and upregulation of glycolytic machinery) toward T-cell activating stimuli. Notably, MSCs express indoleamine-2,3-dioxygenase (IDO), which mediates T-cell suppressive tryptophan catabolism. Our observations suggest that IDO-induced tryptophan depletion interferes with a tryptophan-sufficiency signal that promotes cellular mTOR activation. Despite an immediate suppression of T-cell responses, MSCs foster a metabolically quiescent T-cell phenotype characterized by reduced mTOR signaling and glycolysis, increased autophagy, and lower oxidative stress levels. In fact, those features have previously been shown to promote generation of long-lived memory cells and it remains to be elucidated how MSC-induced metabolic effects shape in vivo T-cell immunity.
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| 6. |
- Davies, LC, et al.
(författare)
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Mesenchymal Stromal Cell Secretion of Programmed Death-1 Ligands Regulates T Cell Mediated Immunosuppression
- 2017
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 35:3, s. 766-776
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Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stromal cells (MSCs) exert broad immunosuppressive potential, modulating the activity of cells of innate and adaptive immune systems. As MSCs become accepted as a therapeutic option for the treatment of immunological disorders such as Graft versus Host Disease, our need to understand the intricate details by which they exert their effects is crucial. Programmed death-1 (PD-1) is an important regulator in T cell activation and homeostatic control. It has been reported that this pathway may be important in contact-dependent mediated immunomodulation by MSCs. The aim of this study was to establish whether MSCs, in addition to their cell-surface expression, are able to secrete PD-1 ligands (PD-L1 and PD-L2) and their potential importance in modulating contact-independent mechanisms of MSC immunosuppression. Here we report that MSCs express and secrete PD-L1 and PD-L2 and that this is regulated by exposure to interferon γ and tumor necrosis factor α. MSCs, via their secretion of PD-1 ligands, suppress the activation of CD4+ T cells, downregulate interleukin-2 secretion and induce irreversible hyporesponsiveness and cell death. Suppressed T cells demonstrated a reduction in AKT phosphorylation at T308 and a subsequent increase in FOXO3 expression that could be reversed with blockade of PD-L1. In conclusion, we demonstrate for the first time, that MSCs are able to secrete PD-1 ligands, with this being the first known report of a biological role for PD-L2 in MSCs. These soluble factors play an important role in modulating immunosuppressive effects of MSCs directly on T cell behavior and induction of peripheral tolerance.
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| 7. |
- Delsing, Louise, et al.
(författare)
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Barrier properties and transcriptome expression in human iPSC-derived models of the blood-brain barrier
- 2018
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Ingår i: Stem Cells. - : AlphaMed Press, Inc.. - 1066-5099 .- 1549-4918. ; 36:12, s. 1816-1827
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Tidskriftsartikel (refereegranskat)abstract
- Cell-based models of the blood-brain barrier (BBB) are important for increasing the knowledge of BBB formation, degradation and brain exposure of drug substances. Human models are preferred over animal models because of inter-species differences in BBB structure and function. However, access to human primary BBB tissue is limited and has shown degeneration of BBB functions in vitro. Human induced pluripotent stem cells (iPSCs) can be used to generate relevant cell types to model the BBB with human tissue. We generated a human iPSC-derived model of the BBB that includes endothelial cells in co-culture with pericytes, astrocytes and neurons. Evaluation of barrier properties showed that the endothelial cells in our co-culture model have high transendothelial electrical resistance, functional efflux and ability to discriminate between CNS permeable and non-permeable substances. Whole genome expression profiling revealed transcriptional changes that occur in co-culture, including upregulation of tight junction proteins such as claudins and neurotransmitter transporters. Pathway analysis implicated changes in the WNT, TNF and PI3K-Akt pathways upon co-culture. Our data suggests that co-culture of iPSC-derived endothelial cells promotes barrier formation on a functional and transcriptional level. The information about gene expression changes in co-culture can be used to further improve iPSC-derived BBB models through selective pathway manipulation.
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| 8. |
- Draganova, Kalina, et al.
(författare)
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Wnt/β‐Catenin Signaling Regulates Sequential Fate Decisions of Murine Cortical Precursor Cells
- 2015
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Ingår i: Stem Cells. - Durham, United States : AlphaMed Press, Inc.. - 1066-5099 .- 1549-4918. ; 33:1, s. 170-182
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Tidskriftsartikel (refereegranskat)abstract
- The fate of neural progenitor cells (NPCs) is determined by a complex interplay of intrinsic programs and extrinsic signals, very few of which are known. β-Catenin transduces extracellular Wnt signals, but also maintains adherens junctions integrity. Here, we identify for the first time the contribution of β-catenin transcriptional activity as opposed to its adhesion role in the development of the cerebral cortex by combining a novel β-catenin mutant allele with conditional inactivation approaches. Wnt/β-catenin signaling ablation leads to premature NPC differentiation, but, in addition, to a change in progenitor cell cycle kinetics and an increase in basally dividing progenitors. Interestingly, Wnt/β-catenin signaling affects the sequential fate switch of progenitors, leading to a shortened neurogenic period with decreased number of both deep and upper-layer neurons and later, to precocious astrogenesis. Indeed, a genome-wide analysis highlighted the premature activation of a corticogenesis differentiation program in the Wnt/β-catenin signaling-ablated cortex. Thus, β-catenin signaling controls the expression of a set of genes that appear to act downstream of canonical Wnt signaling to regulate the stage-specific production of appropriate progenitor numbers, neuronal subpopulations, and astroglia in the forebrain.
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| 9. |
- Gao, H, et al.
(författare)
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CD36 Is a Marker of Human Adipocyte Progenitors with Pronounced Adipogenic and Triglyceride Accumulation Potential
- 2017
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 35:7, s. 1799-1814
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Tidskriftsartikel (refereegranskat)abstract
- White adipose tissue (WAT) expands in part through adipogenesis, a process involving fat cell generation and fatty acid (FA) storage into triglycerides (TGs). Several findings suggest that inter-individual and regional variations in adipogenesis are linked to metabolic complications. We aimed to identify cellular markers that define human adipocyte progenitors (APs) with pronounced adipogenic/TG storage ability. Using an unbiased single cell screen of passaged human adipose-derived stromal cells (hADSCs), we identified cell clones with similar proliferation rates but discordant capabilities to undergo adipogenic differentiation. Transcriptomic analyses prior to induction of differentiation showed that adipogenic clones displayed a significantly higher expression of CD36, encoding the scavenger receptor CD36. CD36+ hADSCs, in comparison with CD36-cells, displayed almost complete adipogenic differentiation while CD36 RNAi attenuated lipid accumulation. Similar findings were observed in primary CD45-/CD34+/CD31-APs isolated from human WAT where the subpopulation of MSCA1+/CD36+ cells displayed a significantly higher differentiation degree/TG storage capacity than MSCA1+/CD36-cells. Functional analyses in vitro and ex vivo confirmed that CD36 conferred APs an increased capacity to take up FAs thereby facilitating terminal differentiation. Among primary APs from subcutaneous femoral, abdominal and visceral human WAT, the fraction of CD36+ cells was significantly higher in depots associated with higher adipogenesis and reduced metabolic risk (i.e., femoral WAT). We conclude that CD36 marks APs with pronounced adipogenic potential, most probably by facilitating lipid uptake. This may be of value in developing human adipocyte cell clones and possibly in linking regional variations in adipogenesis to metabolic phenotype.
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| 10. |
- Lu, J, et al.
(författare)
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Polycystin-2 Plays an Essential Role in Glucose Starvation-Induced Autophagy in Human Embryonic Stem Cell-Derived Cardiomyocytes
- 2018
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 36:4, s. 501-513
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Tidskriftsartikel (refereegranskat)abstract
- Autophagy is a process essential for cell survival under stress condition. The patients with autosomal dominant polycystic kidney disease, which is caused by polycystin-1 or polycystin-2 (PKD2) mutation, display cardiovascular abnormalities and dysregulation in autophagy. However, it is unclear whether PKD2 plays a role in autophagy. In the present study, we explored the functional role of PKD2 in autophagy and apoptosis in human embryonic stem cell-derived cardiomyocytes. HES2 hESC line-derived cardiomyocytes (HES2-CMs) were transduced with adenoviral-based PKD2-shRNAs (Ad-PKD2-shRNAs), and then cultured with normal or glucose-free medium for 3 hours. Autophagy was upregulated in HES2-CMs under glucose starvation, as indicated by increased microtubule-associated protein 1 light chain 3-II level in immunoblots and increased autophagosome and autolysosome formation. Knockdown of PKD2 reduced the autophagic flux and increased apoptosis under glucose starvation. In Ca2+ measurement, Ad-PKD2-shRNAs reduced caffeine-induced cytosolic Ca2+ rise. Co-immunoprecipitation and in situ proximity ligation assay demonstrated an increased physical interaction of PKD2 with ryanodine receptor 2 (RyR2) under glucose starvation condition. Furthermore, Ad-PKD2-shRNAs substantially attenuated the starvation-induced activation of AMP-activated protein kinase (AMPK) and inactivation of mammalian target of rapamycin (mTOR). The present study for the first time demonstrates that PKD2 functions to promote autophagy under glucose starvation, thereby protects cardiomyocytes from apoptotic cell death. The mechanism may involve PKD2 interaction with RyR2 to alter Ca2+ release from sarcoplasmic reticulum, consequently modulating the activity of AMPK and mTOR, resulting in alteration of autophagy and apoptosis.
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| 11. |
- Malinverno, Matteo, et al.
(författare)
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Peg3/PW1 Is a Marker of a Subset of Vessel Associated Endothelial Progenitors
- 2017
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Ingår i: Stem Cells. - : WILEY. - 1066-5099 .- 1549-4918. ; 35:5, s. 1328-1340
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Tidskriftsartikel (refereegranskat)abstract
- Vascular associated endothelial cell (ECs) progenitors are still poorly studied and their role in the newly forming vasculature at embryonic or postnatal stage remains elusive. In the present work, we first defined a set of genes highly expressed during embryo development and strongly downregulated in the adult mouse. In this group, we then concentrated on the progenitor cell marker Peg3/PW1. By in vivo staining of the vasculature we found that only a subset of cells coexpressed endothelial markers and PW1. These cells were quite abundant in the embryo vasculature but declined in number at postnatal and adult stages. Using a reporter mouse for PW1 expression, we have been able to isolate PW1-positive (PW1posECs) and negative endothelial cells (PW1negECs). PW1-positive cells were highly proliferative in comparison to PW1negECs and were able to form colonies when seeded at clonal dilution. Furthermore, by RNAseq analysis, PW1posECs expressed endothelial cell markers together with mesenchymal and stem cell markers. When challenged by endothelial growth factors in vitro, PW1posECs were able to proliferate more than PW1negECs and to efficiently form new vessels in vivo. Taken together these data identify a subset of vessel associated endothelial cells with characteristics of progenitor cells. Considering their high proliferative potential these cells may be of particular importance to design therapies to improve the perfusion of ischemic tissues or to promote vascular repair.
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| 12. |
- Moya, A, et al.
(författare)
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Quiescence Preconditioned Human Multipotent Stromal Cells Adopt a Metabolic Profile Favorable for Enhanced Survival under Ischemia
- 2017
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 35:1, s. 181-196
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Tidskriftsartikel (refereegranskat)abstract
- A major impediment to the development of therapies with mesenchymal stem cells/multipotent stromal cells (MSC) is the poor survival and engraftment of MSCs at the site of injury. We hypothesized that lowering the energetic demand of MSCs by driving them into a quiescent state would enhance their survival under ischemic conditions. Human MSCs (hMSCs) were induced into quiescence by serum deprivation (SD) for 48 hours. Such preconditioned cells (SD-hMSCs) exhibited reduced nucleotide and protein syntheses compared to unpreconditioned hMSCs. SD-hMSCs sustained their viability and their ATP levels upon exposure to severe, continuous, near-anoxia (0.1% O2) and total glucose depletion for up to 14 consecutive days in vitro, as they maintained their hMSC multipotential capabilities upon reperfusion. Most importantly, SD-hMSCs showed enhanced viability in vivo for the first week postimplantation in mice. Quiescence preconditioning modified the energy-metabolic profile of hMSCs: it suppressed energy-sensing mTOR signaling, stimulated autophagy, promoted a shift in bioenergetic metabolism from oxidative phosphorylation to glycolysis and upregulated the expression of gluconeogenic enzymes, such as PEPCK. Since the presence of pyruvate in cell culture media was critical for SD-hMSC survival under ischemic conditions, we speculate that these cells may utilize some steps of gluconeogenesis to overcome metabolic stress. These findings support that SD preconditioning causes a protective metabolic adaptation that might be taken advantage of to improve hMSC survival in ischemic environments.
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| 13. |
- Peric, D, et al.
(författare)
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Cytostatic Effect of Repeated Exposure to Simvastatin: A Mechanism for Chronic Myotoxicity Revealed by the Use of Mesodermal Progenitors Derived from Human Pluripotent Stem Cells
- 2015
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 33:10, s. 2936-2948
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Tidskriftsartikel (refereegranskat)abstract
- Statin treatment of hypercholesterolemia can lead to chronic myotoxicity which is, in most cases, alleviated by drug withdrawal. Cellular and molecular mechanisms of this adverse effect have been elusive, in particular because of the lack of in vitro models suitable for long-term exposures. We have taken advantage of the properties of human pluripotent stem cell-derived mesodermal precursors, that can be maintained unaltered in vitro for a long period of time, to develop a model of repeated exposures to simvastatin during more than 2 weeks. This approach unveiled major differences, both in functional and molecular terms, in response to single versus repeated-dose exposures to simvastatin. The main functional effect of the in vitro simvastatin-induced long-term toxicity was a loss of proliferative capacity in the absence of concomitant cell death, revealing that cytostatic effect could be a major contributor to statin-induced myotoxicity. Comparative analysis of molecular modifications induced by simvastatin short-term versus prolonged exposures demonstrated powerful adaptive cell responses, as illustrated by the dramatic decrease in the number of differentially expressed genes, distinct biological pathway enrichments, and distinct patterns of nutrient transporters expressed at the cell surface. This study underlines the potential of derivatives of human pluripotent stem cells for developing new approaches in toxicology, in particular for chronic toxicity testing. Stem Cells 2015;33:2936–2948
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| 14. |
- Rönn, Roger E., et al.
(författare)
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Reactive Oxygen Species Impair the Function of CD90+ Hematopoietic Progenitors Generated from Human Pluripotent Stem Cells
- 2017
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1066-5099 .- 1549-4918. ; 35:1, s. 197-206
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Tidskriftsartikel (refereegranskat)abstract
- Cell stressors, such as elevated levels of reactive oxygen species (ROS), adversely affect hematopoietic stem cell (HSC) reconstituting ability. However, the effects of ROS have not been evaluated in the context of hematopoietic development from human pluripotent stem cells (hPSCs). Using our previously described in vitro system for efficient derivation of hematopoietic cells from hPSCs, we show that the vast majority of generated hematopoietic cells display supraphysiological levels of ROS compared to fresh cord blood cells. Elevated ROS resulted in DNA damage of the CD34+ hematopoietic fraction and, following functional assays, reduced colony formation and impaired proliferative capacity. Interestingly, all the proliferative potential of the most primitive hematopoietic cells was limited to a small fraction with low ROS levels. We show that elevation of ROS in hPSC-derived hematopoietic cells is contributed by multiple distinct cellular processes. Furthermore, by targeting these molecular processes with 4 unique factors, we could reduce ROS levels significantly, yielding a 22-fold increase in the most primitive CD90+ CD34+ hematopoietic cells with robust growth capacity. We demonstrate that the ROS reducing factors specifically reduced ROS in more primitive hematopoietic fractions, in contrast to endothelial cells that maintained low ROS levels in the cultures. We conclude that high levels of ROS in in vitro differentiation systems of hPSCs is a major determinant in the lack of ability to generate hematopoietic cells with similar proliferation/differentiation potential to in vivo hematopoietic progenitors, and suggest that elevated ROS is a significant barrier to generating hPSC-derived repopulating HSCs. Stem Cells 2017;35:197–206.
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| 15. |
- Tirinato, L, et al.
(författare)
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Lipid droplets: a new player in colorectal cancer stem cells unveiled by spectroscopic imaging
- 2015
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 33:1, s. 35-44
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Tidskriftsartikel (refereegranskat)abstract
- The cancer stem cell (CSC) model is describing tumors as a hierarchical organized system and CSCs are suggested to be responsible for cancer recurrence after therapy. The identification of specific markers of CSCs is therefore of paramount importance. Here, we show that high levels of lipid droplets (LDs) are a distinctive mark of CSCs in colorectal (CR) cancer. This increased lipid content was clearly revealed by label-free Raman spectroscopy and it directly correlates with well-accepted CR-CSC markers as CD133 and Wnt pathway activity. By xenotransplantation experiments, we have finally demonstrated that CR-CSCs overexpressing LDs retain most tumorigenic potential. A relevant conceptual advance in this work is the demonstration that a cellular organelle, the LD, is a signature of CSCs, in addition to molecular markers. A further functional characterization of LDs could lead soon to design new target therapies against CR-CSCs. Stem Cells 2015;33:35–44
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| 16. |
- Williams, K. E., et al.
(författare)
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Focal Adhesion Kinase and Wnt Signaling Regulate Human Ductal Carcinoma In Situ Stem Cell Activity and Response to Radiotherapy
- 2015
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1066-5099 .- 1549-4918. ; 33:2, s. 327-341
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Tidskriftsartikel (refereegranskat)abstract
- Cancer stem cells (CSCs) can avoid or efficiently repair DNA damage from radio and chemotherapy, which suggests they play a role in disease recurrence. Twenty percentage of patients treated with surgery and radiotherapy for ductal carcinoma in situ (DCIS) of the breast recur and our previous data show that high grade DCIS have increased numbers of CSCs. Here, we investigate the role of focal adhesion kinase (FAK) and Wnt pathways in DCIS stem cells and their capacity to survive irradiation. Using DCIS cell lines and patient samples, we demonstrate that CSC-enriched populations are relatively radioresistant and possess high FAK activity. Immunohistochemical studies of active FAK in DCIS tissue show high expression was associated with a shorter median time to recurrence. Treatment with a FAK inhibitor or FAK siRNA in nonadherent and three-dimensional matrigel culture reduced mammosphere formation, and potentiated the effect of 2 Gy irradiation. Moreover, inhibition of FAK in vitro and in vivo decreased self-renewal capacity, levels of Wnt3a and B-Catenin revealing a novel FAK-Wnt axis regulating DCIS stem cell activity. Overall, these data establish that the FAK-Wnt axis is a promising target to eradicate self-renewal capacity and progression of human breast cancers.
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