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Pubblicazioni recenti - cardiac stem
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Integrated paired-end enhancer profiling and whole-genome sequencing reveals recurrent and enhancer hijacking in primary gastric adenocarcinoma.
Gut2019 Sep;():. doi: gutjnl-2018-317612.
Ooi Wen Fong, Nargund Amrita M, Lim Kevin Junliang, Zhang Shenli, Xing Manjie, Mandoli Amit, Lim Jing Quan, Ho Shamaine Wei Ting, Guo Yu, Yao Xiaosai, Lin Suling Joyce, Nandi Tannistha, Xu Chang, Ong Xuewen, Lee Minghui, Tan Angie Lay-Keng, Lam Yue Ning, Teo Jing Xian, Kaneda Atsushi, White Kevin P, Lim Weng Khong, Rozen Steven G, Teh Bin Tean, Li Shang, Skanderup Anders J, Tan Patrick,
Abstract
OBJECTIVE:
Genomic structural variations (SVs) causing rewiring of -regulatory elements remain largely unexplored in gastric cancer (GC). To identify SVs affecting enhancer elements in GC (), we integrated epigenomic enhancer profiles revealed by paired-end H3K27ac ChIP-sequencing from primary GCs with tumour whole-genome sequencing (WGS) data (PeNChIP-seq/WGS).
DESIGN:
We applied PeNChIP-seq to 11 primary GCs and matched normal tissues combined with WGS profiles of >200 GCs. Epigenome profiles were analysed alongside matched RNA-seq data to identify tumour-associated enhancer-based SVs with altered cancer transcription. Functional validation of candidate enhancer-based SVs was performed using CRISPR/Cas9 genome editing, chromosome conformation capture assays (4C-seq, Capture-C) and Hi-C analysis of primary GCs.
RESULTS:
PeNChIP-seq/WGS revealed ~150 enhancer-based SVs in GC. The majority (63%) of SVs linked to target gene deregulation were associated with increased tumour expression. Enhancer-based SVs targeting , a key driver of therapy resistance, occurred in 8% of patients frequently juxtaposing diverse distal enhancers to proximal regions. -rearranged GCs were associated with high expression, disrupted topologically associating domain (TAD) boundaries, and novel TAD interactions in -rearranged primary tumours. We also observed enhancer-based SVs, previously noted in colorectal cancer, highlighting a common non-coding genetic driver alteration in gastric and colorectal malignancies.
CONCLUSION:
Integrated paired-end NanoChIP-seq and WGS of gastric tumours reveals tumour-associated regulatory SV in regions associated with both simple and complex genomic rearrangements. Genomic rearrangements may thus exploit enhancer-hijacking as a common mechanism to drive oncogene expression in GC.
© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.
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Key Regulators of Cardiovascular Differentiation and Regeneration: Harnessing the Potential of Direct Reprogramming to Treat Heart Failure.
J Card Fail2019 Sep;():. doi: S1071-9164(19)30366-5.
Ieda Masaki,
Abstract
Cardiovascular diseases remain a leading cause of death worldwide, with the number of patients with heart failure increasing rapidly in aging societies. As adult cardiomyocytes are terminally differentiated cells and opportunities for heart transplantation are very limited, regenerative medicine may become a game changer in heart failure treatment. To develop strategies for generating cardiomyocytes, vascular cells, and other supporting cells, it is necessary to understand the mechanism of cardiovascular differentiation during development and from pluripotent stem cells. Master regulators for cardiovascular differentiation can generate new cardiomyocytes and vascular cells directly from other differentiated cells such as fibroblasts. Fibroblasts can be directly reprogrammed into cardiomyocytes by overexpressing a combination of three cardiac-specific transcription factors (Gata4, Mef2c, Tbx5) both in vitro and in vivo, which restores cardiac function after myocardial infarction in mice. Moreover, a direct reprogramming-based approach can be used to identify new key regulators of the cardiovascular mesoderm, which can differentiate into all three types of cardiovascular cells including cardiomyocytes, endothelial cells, and smooth muscle cells. This review provides a perspective on how key regulators for cardiovascular differentiation and regeneration can be identified and used to develop new treatments for heart failure.
Copyright © 2019. Published by Elsevier Inc.
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Bioreactor-based 3D human myocardial ischemia/reperfusion in vitro model: a novel tool to unveil key paracrine factors upon AMI.
Transl Res2019 Sep;():. doi: S1931-5244(19)30194-X.
Sebastião Maria J, Gomes-Alves Patrícia, Reis Ivo, Sanchez Belén, Palacios Itziar, Serra Margarida, Alves Paula M,
Abstract
During acute myocardial infarction (AMI), Ischemia/Reperfusion (I/R) injury causes cardiomyocyte (CM) death and loss of tissue function, making AMI one of the major causes of death worldwide. Cell-based in vitro models of I/R injury have been increasingly used as a complementary approach to preclinical research. However, most approaches use murine cells in 2D culture setups, which are not able to recapitulate human cellular physiology, as well as nutrient and gas gradients occurring in the myocardium. In this work we established a novel human in vitro model of myocardial I/R injury using CMs derived from human induced pluripotent stem cells (hiPSC-CMs), which were cultured as 3D aggregates in stirred tank bioreactors. We were able to recapitulate important hallmarks of AMI, including loss of CM viability with disruption of cellular ultrastructure, increased angiogenic potential, and secretion of key proangiogenic and proinflammatory cytokines. Conditioned medium was further used to probe human cardiac progenitor cells (hCPCs) response to paracrine cues from injured hiPSC-CMs through quantitative whole proteome analysis (SWATH-MS). I/R injury hiPSC-CM conditioned media incubation caused upregulation of hCPC proteins associated with migration, proliferation, paracrine signaling, and stress response-related pathways, when compared to the control media incubation. Our results indicate that the model developed herein can serve as a novel tool to interrogate mechanisms of action of human cardiac populations upon AMI.
Copyright © 2019. Published by Elsevier Inc.
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YAP/TEAD3 signal mediates cardiac lineage commitment of human-induced pluripotent stem cells.
J Cell Physiol2019 Sep;():. doi: 10.1002/jcp.29179.
Han Zhenbo, Yu Ying, Cai Benzhi, Xu Zihang, Bao Zhengyi, Zhang Ying, Bamba Djibril, Ma Wenya, Gao Xinlu, Yuan Ye, Zhang Lai, Yu Meixi, Liu Shenzhen, Yan Gege, Jin Mengyu, Huang Qi, Wang Xiuxiu, Hua Bingjie, Yang Fan, Pan Zhenwei, Liang Haihai, Liu Yu,
Abstract
Cardiomyocytes differentiated from human-induced pluripotent stem cells (hiPSCs) hold great potential for therapy of heart diseases. However, the underlying mechanisms of its cardiac differentiation have not been fully elucidated. Hippo-YAP signal pathway plays important roles in cell differentiation, tissue homeostasis, and organ size. Here, we identify the role of Hippo-YAP signal pathway in determining cardiac differentiation fate of hiPSCs. We found that cardiac differentiation of hiPSCs were significantly inhibited after treatment with verteporfin (a selective and potent YAP inhibitor). During hiPSCs differentiation from mesoderm cells (MESs) into cardiomyocytes, verteporfin treatment caused the cells retained in the earlier cardiovascular progenitor cells (CVPCs) stage. Interestingly, during hiPSCs differentiation from CVPC into cardiomyocytes, verteporfin treatment induced cells dedifferentiation into the earlier CVPC stage. Mechanistically, we found that YAP interacted with transcriptional enhanced associate domain transcription factor 3 (TEAD3) to regulate cardiac differentiation of hiPSCs during the CVPC stage. Consistently, RNAi-based silencing of TEAD3 mimicked the phenotype as the cells treated with verteporfin. Collectively, our study suggests that YAP-TEAD3 signaling is important for cardiomyocyte differentiation of hiPSCs. Our findings provide new insight into the function of Hippo-YAP signal in cardiovascular lineage commitment.
© 2019 Wiley Periodicals, Inc.
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Simultaneous measurement of excitation-contraction coupling parameters identifies mechanisms underlying contractile responses of hiPSC-derived cardiomyocytes.
Nat Commun2019 Sep;10(1):4325. doi: 10.1038/s41467-019-12354-8.
van Meer Berend J, Krotenberg Ana, Sala Luca, Davis Richard P, Eschenhagen Thomas, Denning Chris, Tertoolen Leon G J, Mummery Christine L,
Abstract
Cardiomyocytes from human induced pluripotent stem cells (hiPSC-CMs) are increasingly recognized as valuable for determining the effects of drugs on ion channels but they do not always accurately predict contractile responses of the human heart. This is in part attributable to their immaturity but the sensitivity of measurement tools may also be limiting. Measuring action potential, calcium flux or contraction individually misses critical information that is captured when interrogating the complete excitation-contraction coupling cascade simultaneously. Here, we develop an hypothesis-based statistical algorithm that identifies mechanisms of action. We design and build a high-speed optical system to measure action potential, cytosolic calcium and contraction simultaneously using fluorescent sensors. These measurements are automatically processed, quantified and then assessed by the algorithm. Multiplexing these three critical physical features of hiPSC-CMs allows identification of all major drug classes affecting contractility with detection sensitivities higher than individual measurement of action potential, cytosolic calcium or contraction.
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Perlecan regulates pericyte dynamics in the maintenance and repair of the blood-brain barrier.
J Cell Biol2019 Sep;():. doi: jcb.201807178.
Nakamura Kuniyuki, Ikeuchi Tomoko, Nara Kazuki, Rhodes Craig S, Zhang Peipei, Chiba Yuta, Kazuno Saiko, Miura Yoshiki, Ago Tetsuro, Arikawa-Hirasawa Eri, Mukouyama Yoh-Suke, Yamada Yoshihiko,
Abstract
Ischemic stroke causes blood-brain barrier (BBB) breakdown due to significant damage to the integrity of BBB components. Recent studies have highlighted the importance of pericytes in the repair process of BBB functions triggered by PDGFR? up-regulation. Here, we show that perlecan, a major heparan sulfate proteoglycan of basement membranes, aids in BBB maintenance and repair through pericyte interactions. Using a transient middle cerebral artery occlusion model, we found larger infarct volumes and more BBB leakage in conditional perlecan ()-deficient (TG) mice than in control mice. Control mice showed increased numbers of pericytes in the ischemic lesion, whereas TG mice did not. At the mechanistic level, pericytes attached to recombinant perlecan C-terminal domain V (perlecan DV, endorepellin). Perlecan DV enhanced the PDGF-BB-induced phosphorylation of PDGFR?, SHP-2, and FAK partially through integrin ?5?1 and promoted pericyte migration. Perlecan therefore appears to regulate pericyte recruitment through the cooperative functioning of PDGFR? and integrin ?5?1 to support BBB maintenance and repair following ischemic stroke.
This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply.
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Longitudinal dissociation and transition in thickness of the His-Purkinje system cause various QRS waveforms of surface ECG under His bundle pacing: a simulation study based on clinical observations.
J Cardiovasc Electrophysiol2019 Sep;():. doi: 10.1111/jce.14191.
Okada Jun-Ichi, Fujiu Katsuhito, Washio Takumi, Sugiura Seiryo, Hisada Toshiaki, Hasumi Eriko, Komuro Issei,
Abstract
AIMS:
His bundle pacing (HBP) is a feasible and reliable alternative to conventional right ventricular pacing (RVP), but associated ECG changes have not been well studied. This study aimed to determine the mechanisms underlying ECG changes associated with HBP using patient-specific multi-scale heart simulations.
METHODS:
ECGs were recorded in two patients who were treated by HBP under a native rhythm and HBP at high and low voltages. We created patient-specific multi-scale simulation heart models of these patients and performed ECG simulation under these conditions. Using these results and detailed information on the electrical field around the pacing lead, we investigated mechanisms underlying the observed ECG changes.
RESULTS:
Heart simulations successfully reproduced ECGs under a native rhythm for both cases. In case 1, nonselective HBP produced a left bundle branch (LBB) block pattern, which was reproduced as selective right bundle branch (RBB) pacing. However, in case 2, ECG under nonselective HBP showed a RBB block pattern, which could not be reproduced by the commonly used framework. Findings on the electrical field and anatomy of the His bundle and its branches suggested that longitudinal dissociation of the His bundle and transition of thickness in the stem of the LBB caused a conduction delay in the RBB to produce these ECG changes in this patient.
CONCLUSION:
Variations in the anatomy of the His bundle and its branches may underlie the diverse ECG responses to HBP. These variations should be taken into account when performing this therapy. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
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A Meta-analysis of Arrhythmia Endpoints in Randomized Controlled Trials of Transendocardial Stem Cell Injections for Chronic Ischemic Heart Disease.
J Cardiovasc Electrophysiol2019 Sep;():. doi: 10.1111/jce.14185.
Fernandes Gilson C, Fernandes Amanda D F, Rivera Manuel, Khan Aisha, Schulman Ivonne H, Lambrakos Litsa K, Myerburg Robert J, Goldberger Jeffrey J, Hare Joshua M, Mitrani Raul D,
Abstract
INTRODUCTION:
The electrophysiologic impact of cell-based therapy on the injured myocardium remains highly controversial. To perform a meta-analysis of studies comparing arrhythmia burden following transendocardial stem cell therapy versus placebo in patients with chronic ischemic heart disease (CIHD).
METHODS AND RESULTS:
PubMed, Embase and Cochrane Central Register of Controlled Trials were searched. No restriction of stem cell type was specified. The outcomes included sustained supraventricular or ventricular arrhythmias (VA), sudden cardiac death (SCD) and resuscitated sudden cardiac arrest (SCA). Effect sizes were reported as odds-ratio (OR) and 95% CI. Poisson regression was used to account for zero-events data. Twelve randomized trials that included 736 patients (384 in the cell therapy group and 352 in the placebo group) were analyzed. Six different cell types were used. Follow-up ranged from 6 to 12 months. There was a significant decrease in risk of SCD in the cell therapy group, [FE OR 0.19 (0.04, 0.93); p=0.04]. In subgroup analysis, there was a significantly lower risk of SCD or resuscitated SCA in the cell therapy group limited to studies that did not use skeletal myoblasts, [FE OR 0.23 (0.06, 0.83); p=0.03]. There was no significant difference in the incidence of sustained VA between groups [FE OR 0.91 (0.47, 1.77); p=0.8], even after stratifying by cell type. There was no difference in supraventricular arrhythmias between groups.
CONCLUSION:
Non-skeletal myoblast transendocardial cell therapy was associated with a significantly lower risk of SCD or resuscitated SCA compared to control, with no proarrhythmic effects. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
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Glyoxalase 1 Prevents Chronic Hyperglycemia Induced Heart-Explant Derived Cell Dysfunction.
Theranostics2019 ;9(19):5720-5730. doi: 10.7150/thno.36639.
Villanueva Melanie, Michie Connor, Parent Sandrine, Kanaan Georges N, Rafatian Ghazaleh, Kanda Pushpinder, Ye Bin, Liang Wenbin, Harper Mary-Ellen, Davis Darryl R,
Abstract
Decades of work have shown that diabetes increases the risk of heart disease and worsens clinical outcomes after myocardial infarction. Because diabetes is an absolute contraindication to heart transplant, cell therapy is increasingly being explored as a means of improving heart function for these patients with very few other options. Given that hyperglycemia promotes the generation of toxic metabolites, the influence of the key detoxification enzyme glyoxalase 1 (Glo1) on chronic hyperglycemia induced heart explant-derived cell (EDC) dysfunction was investigated. EDCs were cultured from wild type C57Bl/6 or Glo1 over-expressing transgenic mice 2 months after treatment with the pancreatic beta cell toxin streptozotocin or vehicle. The effects of Glo1 overexpression was evaluated using and models of myocardial ischemia. Chronic hyperglycemia reduced overall culture yields and increased the reactive dicarbonyl cell burden within EDCs. These intrinsic cell changes reduced the angiogenic potential and production of pro-healing exosomes while promoting senescence and slowing proliferation. Compared to intra-myocardial injection of normoglycemic cells, chronic hyperglycemia attenuated cell-mediated improvements in myocardial function and reduced the ability of transplanted cells to promote new blood vessel and cardiomyocyte growth. In contrast, Glo1 overexpression decreased oxidative damage while restoring both cell culture yields and EDC-mediated repair of ischemic myocardium. The latter was associated with enhanced production of pro-healing extracellular vesicles by Glo1 cells without altering the pro-healing microRNA cargo within. Chronic hyperglycemia decreases the regenerative performance of EDCs. Overexpression of Glo1 reduces dicarbonyl stress and prevents chronic hyperglycemia-induced dysfunction by rejuvenating the production of pro-healing extracellular vesicles.
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Protective Effects of Aqueous Extract of Stem Bark on Dexamethasone-Induced Insulin Resistance in Rats.
Adv Pharmacol Sci2019 ;2019():8075163. doi: 10.1155/2019/8075163.
Wego Marius Trésor, Poualeu Kamani Sylviane Laure, Miaffo David, Nchouwet Moise Legentil, Kamanyi Albert, Wansi Ngnokam Sylvie Léa,
Abstract
The aim of this study was to evaluate the effects of the aqueous extract of stem bark on dexamethasone-induced insulin resistance in rats. A quantitative phytochemical study was done on the aqueous extract of for the total phenol, flavonoid, and flavonol determination. Insulin resistance was induced by intraperitoneal injection of dexamethasone (1?mg/kg) for 8?days, one hour before oral administration of different treatments (extract at doses of 60, 120, and 240?mg/kg and metformin at 40?mg/kg). During the test, body weight and blood glucose level were evaluated on days 1 and 8. At the last day of treatment, the glucose tolerance test was performed in rats; after that, blood samples were collected for triglycerides, total cholesterol, LDL and HDL cholesterols, transaminases (ALT and AST), and total protein level determination. Organs (heart, liver, pancreas, and kidneys) were also collected for the relative organ weight determination. The results showed that the aqueous extract of is rich in total phenols, flavonoids, and flavonols. This extract significantly reversed the metabolic alterations (lipid profile, protein level, and transaminase activity) induced by dexamethasone in rats. At doses of 120 and 60?mg/kg, also significantly decreases ( < 0.05; < 0.01) postprandial hyperglycemia in insulin resistance rats. The results suggest that can manage insulin resistance and may be useful for the treatment of type 2 diabetes mellitus.
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Use of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes in Preclinical Cancer Drug Cardiotoxicity Testing: A Scientific Statement From the American Heart Association.
Circ Res2019 Sep;():RES0000000000000291. doi: 10.1161/RES.0000000000000291.
Gintant Gary, Burridge Paul, Gepstein Lior, Harding Sian, Herron Todd, Hong Charles, Jalife José, Wu Joseph C, ,
Abstract
It is now well recognized that many lifesaving oncology drugs may adversely affect the heart and cardiovascular system, including causing irreversible cardiac injury that can result in reduced quality of life. These effects, which may manifest in the short term or long term, are mechanistically not well understood. Research is hampered by the reliance on whole-animal models of cardiotoxicity that may fail to reflect the fundamental biology or cardiotoxic responses of the human myocardium. The emergence of human induced pluripotent stem cell-derived cardiomyocytes as an in vitro research tool holds great promise for understanding drug-induced cardiotoxicity of oncological drugs that may manifest as contractile and electrophysiological dysfunction, as well as structural abnormalities, making it possible to deliver novel drugs free from cardiac liabilities and guide personalized therapy. This article briefly reviews the challenges of cardio-oncology, the strengths and limitations of using human induced pluripotent stem cell-derived cardiomyocytes to represent clinical findings in the nonclinical research space, and future directions for their further use.
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Therapeutic Modulation of the Immune Response in Arrhythmogenic Cardiomyopathy.
Circulation2019 Sep;():. doi: 10.1161/CIRCULATIONAHA.119.040676.
Chelko Stephen P, Asimaki Angeliki, Lowenthal Justin, Bueno-Beti Carlos, Bedja Djahida, Scalco Arianna, Amat-Alarcon Nuria, Andersen Peter, Judge Daniel P, Tung Leslie, Saffitz Jeffrey E,
Abstract
Inflammation is a prominent feature of arrhythmogenic cardiomyopathy (ACM), but whether it contributes to the disease phenotype is not known. To define the role of inflammation in the pathogenesis of ACM, we characterized NF?B signaling in ACM models in vitro and in vivo, and in cardiac myocytes from patient induced pluripotent stem cells (hiPSCs). Activation of NF?B signaling, indicated by increased expression and nuclear accumulation of phospho-RelA/p65, occurred in both an in vitro model of ACM (expression of in neonatal rat ventricular myocytes), and in a robust murine model of ACM (homozygous knock-in of mutant desmoglein-2; ) that recapitulates the cardiac manifestations seen in ACM patients. Bay 11-7082, a small molecule inhibitor of NF?B signaling, prevented development of ACM disease features in vitro (abnormal redistribution of intercalated disk proteins, myocyte apoptosis, release of inflammatory cytokines) and in vivo (myocardial necrosis and fibrosis, LV contractile dysfunction, ECG abnormalities). Hearts of mice expressed markedly increased levels of inflammatory cytokines and chemotactic molecules which were attenuated by Bay 11-7082. Salutary effects of Bay 11-7082 correlated with the extent to which production of selected cytokines had been blocked. NF?B signaling was also activated in cardiac myocytes derived from a patient with ACM. These cells produced and secreted abundant inflammatory cytokines under basal conditions, and this was also greatly reduced by Bay 11-7082. Inflammatory signaling is activated in ACM and it drives key features of the disease. Targeting inflammatory pathways may be an effective new mechanism-based therapy for ACM.
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Mesenchymal stem cell-derived extracellular vesicles improve the molecular phenotype of isolated rat lungs during ischemia/reperfusion injury.
J Heart Lung Transplant2019 Aug;():. doi: S1053-2498(19)31634-1.
Lonati Caterina, Bassani Giulia Alessandra, Brambilla Daniela, Leonardi Patrizia, Carlin Andrea, Maggioni Marco, Zanella Alberto, Dondossola Daniele, Fonsato Valentina, Grange Cristina, Camussi Giovanni, Gatti Stefano,
Abstract
BACKGROUND:
Lung ischemia/reperfusion (IR) injury contributes to the development of severe complications in patients undergoing transplantation. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) exert beneficial actions comparable to those of MSCs without the risks of the cell-based strategy. This research investigated EV effects during IR injury in isolated rat lungs.
METHODS:
An established model of 180-minutes ex vivo lung perfusion (EVLP) was used. At 60 minutes EVs (n?=?5) or saline (n?=?5) were administered. Parallel experiments used labeled EVs to determine EV biodistribution (n?=?4). Perfusate samples were collected to perform gas analysis and to assess the concentration of nitric oxide (NO), hyaluronan (HA), inflammatory mediators, and leukocytes. Lung biopsies were taken at 180 minutes to evaluate HA, adenosine triphosphate (ATP), gene expression, and histology.
RESULTS:
Compared with untreated lungs, EV-treated organs showed decreased vascular resistance and a rise of perfusate NO metabolites. EVs prevented the reduction in pulmonary ATP caused by IR. Increased medium-high-molecular-weight HA was detected in the perfusate and in the lung tissue of the IR?+?EV group. Significant differences in cell count on perfusate and tissue samples, together with induction of transcription and synthesis of chemokines, suggested EV-dependent modulation of leukocyte recruitment. EVs upregulated genes involved in the resolution of inflammation and oxidative stress. Biodistribution analysis showed that EVs were retained in the lung tissue and internalized within pulmonary cells.
CONCLUSIONS:
This study shows multiple novel EV influences on pulmonary energetics, tissue integrity, and gene expression during IR. The use of cell-free therapies during EVLP could constitute a valuable strategy for reconditioning and repair of injured lungs before transplantation.
Copyright © 2019 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.
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Changes of metabolic phenotype of cardiac progenitor cells during differentiation: Neutral effect of stimulation of AMP-activated protein kinase.
Stem Cells Dev2019 Sep;():. doi: 10.1089/scd.2019.0129.
André Emilie, De Pauw Aurélia, Verdoy Roxane, Brusa Davide, Bouzin Caroline, Timmermans Aurélie, Bertrand Luc, Balligand Jean-Luc,
Abstract
Cardiac progenitor cells (CPC) in the adult mammalian heart, as well as exogenous CPC injected at the border zone of infarcted tissue, display very low differentiation rate into cardiac myocytes and marginal repair capacity in the injured heart. Emerging evidence supports an obligatory metabolic shift from glycolysis to oxidative phosphorylation during stem cells differentiation, suggesting that pharmacologic modulation of metabolism may improve CPC differentiation and, potentially, healing properties. In this study, we investigated the metabolic transition underlying CPC differentiation towards cardiac myocytes. In addition, we tested whether activators of AMP-activated protein kinase (AMPK), known to promote mitochondrial biogenesis in other cell types would also improve CPC differentiation. Sca1+ CPC were isolated from adult mouse hearts and their phenotype compared to more mature cardiac myocytes from neonatal hearts (NRCM). Under normoxia, glucose consumption and lactate release were significantly higher in CPC than in NRCM. Both parameters were increased in hypoxia together with increased abundance of Glut1 (glucose transporter), of the monocarboxylic transporter Mct4 (lactate efflux mediator) and of Pfkfb3 (key regulator of glycolytic rate). CPC proliferation was critically dependent on glucose and glutamine availability in the media. Oxygen consumption analysis indicates that, compared to NRCM, CPC exhibited lower basal and maximal respirations with lower Tomm20 protein expression and mitochondrial DNA content. This CPC metabolic phenotype profoundly changed upon in vitro differentiation, with a decrease of glucose consumption and lactate release together with increased abundance of Tnnt2, Pgc-1?, Tomm20 and mitochondrial DNA content. Proliferative CPC express both alpha1 and -2 catalytic subunits of AMPK that is activated by A769662. However, A769662 or resveratrol (an activator of Pgc-1? and AMPK) did not promote either mitochondrial biogenesis or CPC maturation during their differentiation. We conclude that while CPC differentiation is accompanied with an increase of mitochondrial oxidative metabolism, these are not potentiated by activation of AMPK in these cells.
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Combination of Chemical and Neurotrophin Stimulation Modulates Neurotransmitter Receptor Expression and Activity in Transdifferentiating Human Adipose Stromal Cells.
Stem Cell Rev Rep2019 Sep;():. doi: 10.1007/s12015-019-09915-1.
Nery Arthur A, Pereira Ricardo L, Bassaneze Vinicius, Nascimento Isis C, Sherman Lauren S, Rameshwar Pranela, Lameu Claudiana, Ulrich Henning,
Abstract
Adipose stromal cells are promising tools for clinical applications in regeneration therapies, due to their ease of isolation from tissue and its high yield; however, their ability to transdifferentiate into neural phenotypes is still a matter of controversy. Here, we show that combined chemical and neurotrophin stimulation resulted in neuron-like morphology and regulated expression and activity of several genes involved in neurogenesis and neurotransmission as well as ion currents mediated by NMDA and GABA receptors. Among them, expression patterns of genes coding for kinin-B1 and B2, ?7 nicotinic, M1, M3 and M4 muscarinic acetylcholine, glutamatergic (AMPA2 and mGlu2), purinergic P2Y1 and P2Y4 and GABAergic (GABA-A, ?3-subunit) receptors and neuronal nitric oxide synthase were up-regulated compared to levels of undifferentiated cells. Simultaneously, expression levels of P2X1, P2X4, P2X7 and P2Y6 purinergic and M5 muscarinic acetylcholine receptors were down-regulated. Agonist-induced activity levels of the studied receptor classes also augmented during neuronal transdifferentiation. Transdifferentiated cells expressed high levels of neuronal ?3-tubulin, NF-H, NeuN and MAP-2 proteins as well as increased ASCL1, MYT1 and POU3F2 gene expression known to drive neuronal fate determination. The presented work contributes to a better understanding of transdifferentiation induced by neurotrophins for a prospective broad spectrum of medical applications.
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Diverse conditions support near-zero growth in yeast: Implications for the study of cell lifespan.
Microb Cell2019 Aug;6(9):397-413. doi: 10.15698/mic2019.09.690.
Gulli Jordan, Cook Emily, Kroll Eugene, Rosebrock Adam, Caudy Amy, Rosenzweig Frank,
Abstract
Baker's yeast has a finite lifespan and ages in two ways: a mother cell can only divide so many times (its replicative lifespan), and a non-dividing cell can only live so long (its chronological lifespan). Wild and laboratory yeast strains exhibit natural variation for each type of lifespan, and the genetic basis for this variation has been generalized to other eukaryotes, including metazoans. To date, yeast chronological lifespan has chiefly been studied in relation to the rate and mode of functional decline among non-dividing cells in nutrient-depleted batch culture. However, this culture method does not accurately capture two major classes of long-lived metazoan cells: cells that are terminally differentiated and metabolically active for periods that approximate animal lifespan (e.g. cardiac myocytes), and cells that are pluripotent and metabolically quiescent (e.g. stem cells). Here, we consider alternative ways of cultivating so that these different metabolic states can be explored in non-dividing cells: (i) yeast cultured as giant colonies on semi-solid agar, (ii) yeast cultured in retentostats and provided sufficient nutrients to meet minimal energy requirements, and (iii) yeast encapsulated in a semisolid matrix and fed in bioreactors. We review the physiology of yeast cultured under each of these conditions, and explore their potential to provide unique insights into determinants of chronological lifespan in the cells of higher eukaryotes.
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Unnecessary Cervical Epidural Injection in An Octogenarian.
Surg Neurol Int2019 ;10():108. doi: 10.25259/SNI-197-2019.
Epstein Nancy E,
Abstract
Background:
Epidural spine injections (ESI) have no documented long-term efficacy. Furthermore, cervical ESI uniquely risk intramedullary injections with resultant neurological deficits (e.g. monoplegia to quadriplegia), and intravascular vertebral injections (e.g. which potentially contribute to stroke, brain stem infarction).
Case Description:
A patient in his mid-eighties presented with 1 year's duration of neck pain without any accompanying numbness, tingling or weakness in the upper or lower extremities. He had no radiculopathy, myelopathy, or neurological deficit. Two years earlier, the patient sustained a myocardial infarction (MI), requiring over 5 stents and a defibrillator. At the time of presentation, he was still on a baby ASA (81 mg/day), on anti-hypertensives, and cholesterol-lowering medications. His non-contrast cervical CT scan (patient had a pacemaker/defibrillator and could not have an MR) from the summer of 2018 showed no significant spinal cord or nerve root compression at any level. Nevertheless, he was subjected to two cervical epidural injections in the early fall; his baby ASA was stopped 5 days prior to each of these injections. Notably, this placed him at increased risk of MI and/or stroke. When he was seen by neurosurgery, without any neurological deficit or significant cervical radiographic findings, he was referred back to neurology for continued conservative management.
Conclusions:
Patients are increasingly subjected to epidural cervical spinal injections that have no documented long-term efficacy, and expose them to significant risks/complications. This 80+ year-old patient, without a neurological deficit or significant cervical CT-documented pathology, underwent 2 cervical ESI that unnecessarily exposed him to potential cardiac-stent related thrombosis (e.g. stopping ASA for 5 days-a bona-fide requirement for ESI to avoid acute epidural hematomas).
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?-Adrenergic Blocker, Carvedilol, Abolishes Ameliorating Actions of Adipose-Derived Stem Cell Sheets on Cardiac Dysfunction and Remodeling After Myocardial Infarction.
Circ J2019 Sep;():. doi: 10.1253/circj.CJ-19-0261.
Adachi Maya, Watanabe Mai, Kurata Yasutaka, Inoue Yumiko, Notsu Tomomi, Yamamoto Kenshiro, Horie Hiromu, Tanno Shogo, Morita Maki, Miake Junichiro, Hamada Toshihiro, Kuwabara Masanari, Nakasone Naoe, Ninomiya Haruaki, Tsuneto Motokazu, Shirayoshi Yasuaki, Yoshida Akio, Nishimura Motonobu, Yamamoto Kazuhiro, Hisatome Ichiro,
Abstract
BACKGROUND:
Treatment of myocardial infarction (MI) includes inhibition of the sympathetic nervous system (SNS). Cell-based therapy using adipose-derived stem cells (ASCs) has emerged as a novel therapeutic approach to treat heart failure in MI. The purpose of this study was to determine whether a combination of ASC transplantation and SNS inhibition synergistically improves cardiac functions after MI.Methods?and?Results:ASCs were isolated from fat tissues of Lewis rats. In in vitro studies using cultured ASC cells, mRNA levels of angiogenic factors under normoxia or hypoxia, and the effects of norepinephrine and a ?-blocker, carvedilol, on the mRNA levels were determined. Hypoxia increased vascular endothelial growth factor (VEGF) mRNA in ASCs. Norepinephrine further increased VEGF mRNA; this effect was unaffected by carvedilol. VEGF promoted VEGF receptor phosphorylation and tube formation of human umbilical vein endothelial cells, which were inhibited by carvedilol. In in vivo studies using a rat MI model, transplanted ASC sheets improved contractile functions of MI hearts; they also facilitated neovascularization and suppressed fibrosis after MI. These beneficial effects of ASC sheets were abolished by carvedilol. The effects of ASC sheets and carvedilol on MI heart functions were confirmed by Langendorff perfusion experiments using isolated hearts.
CONCLUSIONS:
ASC sheets prevented cardiac dysfunctions and remodeling after MI in a rat model via VEGF secretion. Inhibition of VEGF effects by carvedilol abolished their beneficial effects.
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Stem cell secretome as a new booster for regenerative medicine.
Biosci Trends2019 ;13(4):299-307. doi: 10.5582/bst.2019.01226.
Xia Jufeng, Minamino Shuichi, Kuwabara Kazuma, Arai Shunichi,
Abstract
Stem cells are an undifferentiated cell population that has the ability to develop into many different cell types and also has the ability to repair damaged tissues in some cases. For a long time, the stem cell regenerative paradigm has been based on the assumption that progenitor cells play a critical role in tissue repair by means of their plasticity and differentiation potential. However, recent works suggest that the mechanism underlying the benefits of stem cell transplantation might relate to a paracrine modulatory effect rather than the replacement of affected cells at the site of injury. This paracrine modulatory effect derives from secretome which comprises a diverse host of growth factors, cytokines, chemokines, angiogenic factors, and exosomes which are extracellular vesicles that are produced in the endosomal compartment of most eukaryotic cells and are from about 30 to several hundred nanometers in diameter. The role of these factors is being increasingly recognized as key to the regulation of many physiological processes including leading endogenous and progenitor cells to sites of injury as well as mediating apoptosis, proliferation, migration, and angiogenesis. In reality, the immunomodulatory and paracrine role of these factors may mainly account for the therapeutic effects of stem cells and a number of in vitro and in vivo researches have proved limited stem cell engraftment at the site of injury. As a cell-free way for regenerative medicine therapies, stem cell secretome has shown great potential in a variety of clinical applications including prevention of cardiac disfunction, neurodegenerative disease, type 1 diabetes, hair loss, tumors, and joint osteoarthritis.
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Recent progress in induced pluripotent stem cell-derived cardiac cell sheets for tissue engineering.
Biosci Trends2019 ;13(4):292-298. doi: 10.5582/bst.2019.01227.
Gao Botao, Matsuura Katsuhisa, Shimizu Tatsuya,
Abstract
The past decade has witnessed remarkable development in tissue engineering technologies and stem cells. Our lab has developed a novel technology - "cell sheet technology" for tissue engineering. After the confluent cells are cultured on an innovative temperature-responsive culture dish, the cells can be harvested as an intact sheet by lowering temperature. We have successfully created multiple cell sheet-based tissues for therapies of a vast variety of diseases, in particular, myocardial diseases. On the other side, the discovery of human induced pluripotent stem cells (hiPSC) enables stable production of defined tissue-specific cell types and thus makes it possible to regenerate tissues or even organs for clinical application and in vitro drug screening/disease modeling. Recently, we have combined cell sheet technology and hiPSC-derived cardiac cells for fabrication of functional human cardiac tissues. This review summarizes ongoing challenges in this field and our progresses in solving issues, such as large scale culture of hiPSC-derived cardiac cells, elimination of undifferentiated iPSCs to decrease the risk of tumor formation as well as myocardial tissue fabrication technologies.
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