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Engineering a CRISPRoff Platform to Modulate Expression of Myeloid Cell Leukemia (MCL-1) in Committed Oligodendrocyte Neural Precursor Cells. Bio Protoc 2024; 14:e4913. [PMID: 38213321 PMCID: PMC10777056 DOI: 10.21769/bioprotoc.4913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 01/13/2024] Open
Abstract
In vitro differentiation of human pluripotent stem cell (hPSC) model systems has furthered our understanding of human development. Techniques used to elucidate gene function during early development have encountered technical challenges, especially when targeting embryonic lethal genes. The introduction of CRISPRoff by Nuñez and collaborators provides an opportunity to heritably silence genes during long-term differentiation. We modified CRISPRoff and sgRNA Sleeping Beauty transposon vectors that depend on tetracycline-controlled transcriptional activation to silence the expression of embryonic lethal genes at different stages of differentiation in a stable manner. We provide instructions on how to generate sgRNA transposon vectors that can be used in combination with our CRISPRoff transposon vector and a stable hPSC line. We validate the use of this tool by silencing MCL-1, an anti-apoptotic protein, which results in pre-implantation embryonic lethality in mice; this protein is necessary for oligodendrocyte and hematopoietic stem cell development and is required for the in vitro survival of hPSCs. In this protocol, we use an adapted version of the differentiation protocol published by Douvaras and Fossati (2015) to generate oligodendrocyte lineage cells from human embryonic stem cells (hESCs). After introduction of the CRISPRoff and sgRNAs transposon vectors in hESCs, we silence MCL-1 in committed oligodendrocyte neural precursor cells and describe methods to measure its expression. With the methods described here, users can design sgRNA transposon vectors targeting MCL-1 or other essential genes of interest to study human oligodendrocyte development or other differentiation protocols that use hPSC model systems. Key features • Generation of an inducible CRISPRoff Sleeping Beauty transposon system. • Experiments performed in vitro for generation of inducible CRISPRoff pluripotent stem cell line amenable to oligodendrocyte differentiation. • Strategy to downregulate an essential gene at different stages of oligodendrocyte development.
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Leptomeningeal Neural Organoid (LMNO) Fusions as Models to Study Meninges-Brain Signaling. RESEARCH SQUARE 2023:rs.3.rs-3694849. [PMID: 38168409 PMCID: PMC10760226 DOI: 10.21203/rs.3.rs-3694849/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Neural organoids derived from human induced pluripotent stem cells (iPSCs) provide a model to study the earliest stages of human brain development, including neurogenesis, neural differentiation, and synaptogenesis. However, neural organoids lack supportive tissues and some non-neural cell types that are key regulators of brain development. Neural organoids have instead been co-cultured with non-neural structures and cell types to promote their maturation and model interactions with neuronal cells. One structure that does not form de novo with neural organoids is the meninges, a tri-layered structure that surrounds the CNS and secretes key signaling molecules required for mammalian brain development. Most studies of meninges-brain signaling have been performed in mice or using two-dimensional (2D) cultures of human cells, the latter not recapitulating the architecture and cellular diversity of the tissue. To overcome this, we developed a co-culture system of neural organoids generated from human iPSCs fused with fetal leptomeninges from mice with fluorescently labeled meninges (Col1a1-GFP). These proof-of-concept studies test the stability of the different cell types in the leptomeninges (fibroblast and macrophage) and the fused brain organoid (progenitor and neuron), as well as the interface between the organoid and meningeal tissue. We test the longevity of the fusion pieces after 30 days and 60 days in culture, describe best practices for preparing the meninges sample prior to fusion, and examine the feasibility of single or multiple meninges pieces fused to a single organoid. We discuss potential uses of the current version of the LMNO fusion model and opportunities to improve the system.
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Leptomeningeal Neural Organoid (LMNO) Fusions as Models to Study Meninges-Brain Signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569648. [PMID: 38077064 PMCID: PMC10705555 DOI: 10.1101/2023.12.01.569648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Neural organoids derived from human induced pluripotent stem cells (iPSCs) provide a model to study the earliest stages of human brain development, including neurogenesis, neural differentiation, and synaptogenesis. However, neural organoids lack supportive tissues and some non-neural cell types that are key regulators of brain development. Neural organoids have instead been co-cultured with non-neural structures and cell types to promote their maturation and model interactions with neuronal cells. One structure that does not form de novo with neural organoids is the meninges, a tri-layered structure that surrounds the CNS and secretes key signaling molecules required for mammalian brain development. Most studies of meninges-brain signaling have been performed in mice or using two-dimensional (2D) cultures of human cells, the latter not recapitulating the architecture and cellular diversity of the tissue. To overcome this, we developed a co-culture system of neural organoids generated from human iPSCs fused with fetal leptomeninges from mice with fluorescently labeled meninges (Col1a1-GFP). These proof-of-concept studies test the stability of the different cell types in the leptomeninges (fibroblast and macrophage) and the fused brain organoid (progenitor and neuron), as well as the interface between the organoid and meningeal tissue. We test the longevity of the fusion pieces after 30 days and 60 days in culture, describe best practices for preparing the meninges sample prior to fusion, and examine the feasibility of single or multiple meninges pieces fused to a single organoid. We discuss potential uses of the current version of the LMNO fusion model and opportunities to improve the system.
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Emerging mitochondrial-mediated mechanisms involved in oligodendrocyte development. J Neurosci Res 2023; 101:354-366. [PMID: 36461887 PMCID: PMC9851982 DOI: 10.1002/jnr.25151] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 10/19/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022]
Abstract
Oligodendrocytes are the myelinating glia of the central nervous system and are generated after oligodendrocyte progenitor cells (OPCs) transition into pre-oligodendrocytes and then into myelinating oligodendrocytes. Myelin is essential for proper signal transmission within the nervous system and axonal metabolic support. Although the intrinsic and extrinsic factors that support the differentiation, survival, integration, and subsequent myelination of appropriate axons have been well investigated, little is known about how mitochondria-related pathways such as mitochondrial dynamics, bioenergetics, and apoptosis finely tune these developmental events. Previous findings suggest that changes to mitochondrial morphology act as an upstream regulatory mechanism of neural stem cell (NSC) fate decisions. Whether a similar mechanism is engaged during OPC differentiation has yet to be elucidated. Maintenance of mitochondrial dynamics is vital for regulating cellular bioenergetics, functional mitochondrial networks, and the ability of cells to distribute mitochondria to subcellular locations, such as the growing processes of oligodendrocytes. Myelination is an energy-consuming event, thus, understanding the interplay between mitochondrial dynamics, metabolism, and apoptosis will provide further insight into mechanisms that mediate oligodendrocyte development in healthy and disease states. Here we will provide a concise overview of oligodendrocyte development and discuss the potential contribution of mitochondrial mitochondrial-mediated mechanisms to oligodendrocyte bioenergetics and development.
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DRP1 mutations associated with EMPF1 encephalopathy alter mitochondrial membrane potential and metabolic programs. J Cell Sci 2023; 136:jcs260370. [PMID: 36763487 PMCID: PMC10657212 DOI: 10.1242/jcs.260370] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 12/22/2022] [Indexed: 02/11/2023] Open
Abstract
Mitochondria and peroxisomes are dynamic signaling organelles that constantly undergo fission, driven by the large GTPase dynamin-related protein 1 (DRP1; encoded by DNM1L). Patients with de novo heterozygous missense mutations in DNM1L present with encephalopathy due to defective mitochondrial and peroxisomal fission (EMPF1) - a devastating neurodevelopmental disease with no effective treatment. To interrogate the mechanisms by which DRP1 mutations cause cellular dysfunction, we used human-derived fibroblasts from patients who present with EMPF1. In addition to elongated mitochondrial morphology and lack of fission, patient cells display lower coupling efficiency, increased proton leak and upregulation of glycolysis. Mitochondrial hyperfusion also results in aberrant cristae structure and hyperpolarized mitochondrial membrane potential. Peroxisomes show a severely elongated morphology in patient cells, which is associated with reduced respiration when cells are reliant on fatty acid oxidation. Metabolomic analyses revealed impaired methionine cycle and synthesis of pyrimidine nucleotides. Our study provides insight into the role of mitochondrial dynamics in cristae maintenance and the metabolic capacity of the cell, as well as the disease mechanism underlying EMPF1.
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Functional Overlap of Inborn Errors of Immunity and Metabolism Genes Define T Cell Immunometabolic Vulnerabilities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.24.525419. [PMID: 36747715 PMCID: PMC9900827 DOI: 10.1101/2023.01.24.525419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inborn Errors of Metabolism (IEM) and Immunity (IEI) are Mendelian diseases in which complex phenotypes and patient rarity can limit clinical annotations. Few genes are assigned to both IEM and IEI, but immunometabolic demands suggest functional overlap is underestimated. We applied CRISPR screens to test IEM genes for immunologic roles and IEI genes for metabolic effects and found considerable crossover. Analysis of IEM showed N-linked glycosylation and the de novo hexosamine synthesis enzyme, Gfpt1 , are critical for T cell expansion and function. Interestingly, Gfpt1 -deficient T H 1 cells were more affected than T H 17 cells, which had increased Nagk for salvage UDP-GlcNAc synthesis. Screening IEI genes showed the transcription factor Bcl11b promotes CD4 + T cell mitochondrial activity and Mcl1 expression necessary to prevent metabolic stress. These data illustrate a high degree of functional overlap of IEM and IEI genes and point to potential immunometabolic mechanisms for a previously unappreciated set of these disorders. HIGHLIGHTS Inborn errors of immunity and metabolism have greater overlap than previously known Gfpt1 deficiency causes an IEM but also selectively regulates T cell subset fate Loss of Bcl11b causes a T cell deficiency IEI but also harms mitochondrial function Many IEM may have immune defects and IEI may be driven by metabolic mechanisms.
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Uropathogenic Escherichia coli subverts mitochondrial metabolism to enable intracellular bacterial pathogenesis in urinary tract infection. Nat Microbiol 2022; 7:1348-1360. [PMID: 35995841 PMCID: PMC9756876 DOI: 10.1038/s41564-022-01205-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 07/19/2022] [Indexed: 01/18/2023]
Abstract
Urinary tract infections are among the most common human bacterial infections and place a significant burden on healthcare systems due to associated morbidity, cost and antibiotic use. Despite being a facultative anaerobe, uropathogenic Escherichia coli, the primary cause of urinary tract infections, requires aerobic respiration to establish infection in the bladder. Here, by combining bacterial genetics with cell culture and murine models of infection, we demonstrate that the widely conserved respiratory quinol oxidase cytochrome bd is required for intracellular infection of urothelial cells. Through a series of genetic, biochemical and functional assays, we show that intracellular oxygen scavenging by cytochrome bd alters mitochondrial physiology by reducing the efficiency of mitochondrial respiration, stabilizing the hypoxia-inducible transcription factor HIF-1 and promoting a shift towards aerobic glycolysis. This bacterially induced rewiring of host metabolism antagonizes apoptosis, thereby protecting intracellular bacteria from urothelial cell exfoliation and preserving their replicative niche. These results reveal the metabolic basis for intracellular bacterial pathogenesis during urinary tract infection and identify subversion of mitochondrial metabolism as a bacterial strategy to facilitate persistence within the urinary tract.
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Human iPSC-derived cerebral organoids model features of Leigh syndrome and reveal abnormal corticogenesis. Development 2022; 149:275911. [PMID: 35792828 PMCID: PMC9357378 DOI: 10.1242/dev.199914] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 05/18/2022] [Indexed: 01/12/2023]
Abstract
Leigh syndrome (LS) is a rare, inherited neurometabolic disorder that presents with bilateral brain lesions caused by defects in the mitochondrial respiratory chain and associated nuclear-encoded proteins. We generated human induced pluripotent stem cells (iPSCs) from three LS patient-derived fibroblast lines. Using whole-exome and mitochondrial sequencing, we identified unreported mutations in pyruvate dehydrogenase (GM0372, PDH; GM13411, MT-ATP6/PDH) and dihydrolipoyl dehydrogenase (GM01503, DLD). These LS patient-derived iPSC lines were viable and capable of differentiating into progenitor populations, but we identified several abnormalities in three-dimensional differentiation models of brain development. LS patient-derived cerebral organoids showed defects in neural epithelial bud generation, size and cortical architecture at 100 days. The double mutant MT-ATP6/PDH line produced organoid neural precursor cells with abnormal mitochondrial morphology, characterized by fragmentation and disorganization, and showed an increased generation of astrocytes. These studies aim to provide a comprehensive phenotypic characterization of available patient-derived cell lines that can be used to study Leigh syndrome.
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Mitochondrial Fission is Essential to Maintain Cristae Morphology and Bioenergetics. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Revealing the Impact of Mitochondrial Fitness During Early Neural Development Using Human Brain Organoids. Front Mol Neurosci 2022; 15:840265. [PMID: 35571368 PMCID: PMC9102998 DOI: 10.3389/fnmol.2022.840265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial homeostasis -including function, morphology, and inter-organelle communication- provides guidance to the intrinsic developmental programs of corticogenesis, while also being responsive to environmental and intercellular signals. Two- and three-dimensional platforms have become useful tools to interrogate the capacity of cells to generate neuronal and glia progeny in a background of metabolic dysregulation, but the mechanistic underpinnings underlying the role of mitochondria during human neurogenesis remain unexplored. Here we provide a concise overview of cortical development and the use of pluripotent stem cell models that have contributed to our understanding of mitochondrial and metabolic regulation of early human brain development. We finally discuss the effects of mitochondrial fitness dysregulation seen under stress conditions such as metabolic dysregulation, absence of developmental apoptosis, and hypoxia; and the avenues of research that can be explored with the use of brain organoids.
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Stem cell conversion to the cardiac lineage requires nucleotide signalling from apoptosing cells. Nat Cell Biol 2022; 24:434-447. [PMID: 35414019 PMCID: PMC9054036 DOI: 10.1038/s41556-022-00888-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 03/04/2022] [Indexed: 12/22/2022]
Abstract
Pluripotent stem cells can be driven by manipulation of Wnt signalling through a series of states similar to those that occur during early embryonic development, transitioning from an epithelial phenotype into the cardiogenic-mesoderm lineage and ultimately into functional cardiomyocytes. Strikingly, we observed that initiation of differentiation in induced pluripotent stem cells (iPSCs) and embryonic stem cells triggers widespread apoptosis, followed by a synchronous epithelial-mesenchymal transition (EMT). Apoptosis is caused by the absence of bFGF in the differentiation medium. EMT requires induction of the transcription factors SNAI1 and SNAI2 downstream of MESP1 expression, and double knockout of SNAI1 and SNAI2 or loss of MESP1 in iPSCs blocks EMT and prevents cardiac differentiation. Remarkably, blockade of early apoptosis, either chemically or by ablation of pro-apoptotic genes, also completely prevents EMT, suppressing even the earliest events in mesoderm conversion, including T/BRA, TBX6 and MESP1 induction. Conditioned medium from WNT-activated wild-type iPSCs overcomes the block to EMT by cells incapable of apoptosis, suggesting involvement of soluble factors from apoptotic cells in mesoderm conversion. Knockout of the PANX1 channel blocked EMT, whereas treatment with a purinergic P2-receptor inhibitor or addition of apyrase demonstrated a requirement for nucleotide triphosphate signalling. ATP and/or UTP was sufficient to induce a partial EMT in apoptosis-incapable cells treated with WNT activator. Notably, knockout of the ATP/UTP-specific P2Y2 receptor blocked EMT and mesoderm induction. We conclude that in addition to acting as chemo-attractants for clearance of apoptotic cells, nucleotides can function as essential paracrine signals that, with WNT signalling, create a logical AND gate for mesoderm specification.
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A taste of the early steps in BAX activation with FLAMBE. CELL REPORTS METHODS 2022; 2:100190. [PMID: 35475223 PMCID: PMC9017131 DOI: 10.1016/j.crmeth.2022.100190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The activation of BAX through intricate intramolecular changes is critical for apoptosis. In this issue of Cell Reports Methods, Gelles et al. report engineering FLAMBE, an elegant fluorescence polarization ligand assay for monitoring the early activation of monomeric BAX via real-time release of a peptide probe, expanding the repertoire of BAX activation assays to the single-molecule level.
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Metformin improves diastolic dysfunction of non-diabetic patients with metabolic syndrome: the MET-DIME randomized trial. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.0913] [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: 11/12/2022] Open
Abstract
Abstract
Background
Metabolic syndrome (MetS) is a cluster of cardiovascular risk factors, including abdominal obesity, dyslipidaemia, arterial hypertension and abnormal glucose homeostasis, which occur together more frequently than by chance. Diastolic dysfunction (DD) is one of the most frequent manifestations of subclinical cardiac involvement of MetS, ultimately leading to heart failure with preserved ejection fraction. Metformin's new potential therapeutic actions include prevention of cardiac remodeling and fibrosis.
Purpose
We aimed to evaluate if metformin improves diastolic function (DF) in non-diabetic patients with MetS.
Methods
A prospective, randomized, open-label, blinded-endpoint trial was conducted over 24 months. Fifty-four non-diabetic adults with MetS and DD (defined as mean e'<10.2cm/s or <7.2cm/s for individuals 40–59 and 60–65 years old, respectively) were randomized to lifestyle counseling (control arm) or lifestyle counseling plus metformin (intervention arm) on a target dose of 1000 mg bid (figure 1). The primary endpoint was the change in mean e' velocity, assessed at 6, 12 and 24 months. Secondary endpoints included improvements in insulin resistance (HOMA-IR), functional capacity (peak oxygen uptake – VO2) and QoL (SF-36 score). Linear mixed effects modelling was used for longitudinal data analysis based on modified intention-to-treat (mITT) and per-protocol (PP) approaches.
Results
Forty-nine patients (mean age=51.8±6.4; 55% males) were included in the mITT analysis. Metformin use, on top of lifestyle counseling, led to an increase in mean e' velocity during follow-up (figure 2), with results at 24 months of +0.67±1.90cm/s (vs. −0.33±1.50cm/s in the control group, p=0.056), which reached statistical significance in PP analysis (+0.80±1.99cm/s vs. −0.37±1.52cm/s, p=0.039). In a random intercept linear mixed model adjusting for age, gender, treatment with drugs targeting the renin-angiotensin-aldosterone axis, presence of heart failure and baseline degree of DD, both mITT and PP analysis showed a statistically significant improvement of DF with metformin over time (β-coefficient=0.28, standard error (SE)=0.13, p=0.034, and β-coefficient=0.35, SE=0.14, p=0.011, respectively). This effect was independent of the observed reduction in insulin resistance. There were no differences regarding peak VO2 nor SF-36 score.
Conclusions
Treatment with metformin of non-diabetic MetS patients with DD, on top of lifestyle counseling, was associated with improved diastolic function.
Funding Acknowledgement
Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Merck Study algorithmPrimary endpoint results
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Common molecular mechanisms of SLC6A1 variant-mediated neurodevelopmental disorders in astrocytes and neurons. Brain 2021; 144:2499-2512. [PMID: 34028503 PMCID: PMC8418336 DOI: 10.1093/brain/awab207] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Solute carrier family 6 member 1 (SLC6A1) is abundantly expressed in the developing brain even before the CNS is formed. Its encoded GABA transporter 1 (GAT-1) is responsible for the reuptake of GABA into presynaptic neurons and glia, thereby modulating neurotransmission. GAT-1 is expressed globally in the brain, in both astrocytes and neurons. The GABA uptake function of GAT-1 in neurons cannot be compensated for by other GABA transporters, while the function in glia can be partially replaced by GABA transporter 3. Recently, many variants in SLC6A1 have been associated with a spectrum of epilepsy syndromes and neurodevelopmental disorders, including myoclonic atonic epilepsy, childhood absence epilepsy, autism, and intellectual disability, but the pathomechanisms associated with these phenotypes remain unclear. The presence of GAT-1 in both neurons and astrocytes further obscures the role of abnormal GAT-1 in the heterogeneous disease phenotype manifestations. Here we examine the impact on transporter trafficking and function of 22 SLC6A1 variants identified in patients with a broad spectrum of phenotypes. We also evaluate changes in protein expression and subcellular localization of the variant GAT-1 in various cell types, including neurons and astrocytes derived from human patient induced pluripotent stem cells. We found that a partial or complete loss-of-function represents a common disease mechanism, although the extent of GABA uptake reduction is variable. The reduced GABA uptake appears to be due to reduced cell surface expression of the variant transporter caused by variant protein misfolding, endoplasmic reticulum retention, and subsequent degradation. Although the extent of reduction of the total protein, surface protein, and the GABA uptake level of the variant transporters is variable, the loss of GABA uptake function and endoplasmic reticulum retention is consistent across induced pluripotent stem cell-derived cell types, including astrocytes and neurons, for the surveyed variants. Interestingly, we did not find a clear correlation of GABA uptake function and the disease phenotypes, such as myoclonic atonic epilepsy versus developmental delay, in this study. Together, our study suggests that impaired transporter protein trafficking and surface expression are the major disease-associated mechanisms associated with pathogenic SLC6A1 variants. Our results resemble findings from pathogenic variants in other genes affecting the GABA pathway, such as GABAA receptors. This study provides critical insight into therapeutic developments for SLC6A1 variant-mediated disorders and implicates that boosting transporter function by either genetic or pharmacological approaches would be beneficial.
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Precise Tuning of Cortical Contractility Regulates Cell Shape during Cytokinesis. Cell Rep 2021; 31:107477. [PMID: 32268086 DOI: 10.1016/j.celrep.2020.03.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/27/2020] [Accepted: 03/13/2020] [Indexed: 01/30/2023] Open
Abstract
The mechanical properties of the actin cortex regulate shape changes during cell division, cell migration, and tissue morphogenesis. We show that modulation of myosin II (MII) filament composition allows tuning of surface tension at the cortex to maintain cell shape during cytokinesis. Our results reveal that MIIA generates cortex tension, while MIIB acts as a stabilizing motor and its inclusion in MII hetero-filaments reduces cortex tension. Tension generation by MIIA drives faster cleavage furrow ingression and bleb formation. We also show distinct roles for the motor and tail domains of MIIB in maintaining cytokinetic fidelity. Maintenance of cortical stability by the motor domain of MIIB safeguards against shape instability-induced chromosome missegregation, while its tail domain mediates cortical localization at the terminal stages of cytokinesis to mediate cell abscission. Because most non-muscle contractile systems are cortical, this tuning mechanism will likely be applicable to numerous processes driven by myosin-II contractility.
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A proteomics approach for the identification of cullin-9 (CUL9) related signaling pathways in induced pluripotent stem cell models. PLoS One 2021; 16:e0248000. [PMID: 33705438 PMCID: PMC7951927 DOI: 10.1371/journal.pone.0248000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/17/2021] [Indexed: 12/13/2022] Open
Abstract
CUL9 is a non-canonical and poorly characterized member of the largest family of E3 ubiquitin ligases known as the Cullin RING ligases (CRLs). Most CRLs play a critical role in developmental processes, however, the role of CUL9 in neuronal development remains elusive. We determined that deletion or depletion of CUL9 protein causes aberrant formation of neural rosettes, an in vitro model of early neuralization. In this study, we applied mass spectrometric approaches in human pluripotent stem cells (hPSCs) and neural progenitor cells (hNPCs) to identify CUL9 related signaling pathways that may contribute to this phenotype. Through LC-MS/MS analysis of immunoprecipitated endogenous CUL9, we identified several subunits of the APC/C, a major cell cycle regulator, as potential CUL9 interacting proteins. Knockdown of the APC/C adapter protein FZR1 resulted in a significant increase in CUL9 protein levels, however, CUL9 does not appear to affect protein abundance of APC/C subunits and adapters or alter cell cycle progression. Quantitative proteomic analysis of CUL9 KO hPSCs and hNPCs identified protein networks related to metabolic, ubiquitin degradation, and transcriptional regulation pathways that are disrupted by CUL9 deletion in both hPSCs. No significant changes in oxygen consumption rates or ATP production were detected in either cell type. The results of our study build on current evidence that CUL9 may have unique functions in different cell types and that compensatory mechanisms may contribute to the difficulty of identifying CUL9 substrates.
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Abstract
Mitochondria are signaling hubs responsible for the generation of energy through oxidative phosphorylation, the production of key metabolites that serve the bioenergetic and biosynthetic needs of the cell, calcium (Ca2+) buffering and the initiation/execution of apoptosis. The ability of mitochondria to coordinate this myriad of functions is achieved through the exquisite regulation of fundamental dynamic properties, including remodeling of the mitochondrial network via fission and fusion, motility and mitophagy. In this Review, we summarize the current understanding of the mechanisms by which these dynamic properties of the mitochondria support mitochondrial function, review their impact on human cortical development and highlight areas in need of further research.
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Metformin in non-diabetic patients with metabolic syndrome and diastolic dysfunction: the MET-DIME randomized trial. Eur Heart J Cardiovasc Imaging 2021. [DOI: 10.1093/ehjci/jeaa356.022] [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: 11/13/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Merck
Background
Metabolic syndrome (MetS) affects one out of 3 adults in the western world and is associated with preclinical diastolic dysfunction that impairs functional capacity and quality of life (QoL).
Purpose
This randomized trial was designed to evaluate if the addition of metformin to the standard treatment of non-diabetic patients with MetS improves diastolic dysfunction.
Methods
Prospective, randomized, open-label, blinded-endpoint trial. Fifty-four non-diabetic adults with MetS and diastolic dysfunction were randomized to lifestyle counseling or lifestyle counseling plus metformin (target dose 1000 mg bid). The primary endpoint was the change in mean e’ velocity (assessed at baseline, 6, 12 and 24 months). Secondary endpoints were improvements in insulin resistance, functional capacity and QoL. Linear mixed effects modelling was used for longitudinal data analysis using modified intention-to-treat (mITT) and per-protocol (PP) approaches.
Results
Forty-nine patients were included in the mITT analysis (mean age = 51.8 ± 6.4; 55% males). Metformin treatment was associated with a significant decrease in HOMA-IR. There was a significantly different mean change in e’ velocity during the study period between trial arms, both in the mITT (at 24 months, change of +0.67 ± 1.90cm/s in metformin arm vs. -0.33 ± 1.50cm/s in control arm) and PP populations (+0.80 ± 1.99cm/s in metformin arm vs. -0.37 ± 1.52cm/s in control arm), using a random intercept linear mixed model. There were no significant differences in peak oxygen uptake and SF-36 scores between trial arms.
Conclusion
Treatment with metformin of non-diabetic MetS patients with diastolic dysfunction, on top of lifestyle counseling, is associated with improved diastolic function.
Abstract Figure.
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Cover Image, Volume 77, Issue 9. Cytoskeleton (Hoboken) 2020. [DOI: 10.1002/cm.21636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Modeling the function of BAX and BAK in early human brain development using iPSC-derived systems. Cell Death Dis 2020; 11:808. [PMID: 32978370 PMCID: PMC7519160 DOI: 10.1038/s41419-020-03002-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 12/27/2022]
Abstract
Intrinsic apoptosis relies on the ability of the BCL-2 family to induce the formation of pores on the outer mitochondrial membrane. Previous studies have shown that both BAX and BAK are essential during murine embryogenesis, and reports in human cancer cell lines identified non-canonical roles for BAX and BAK in mitochondrial fission during apoptosis. BAX and BAK function in human brain development remains elusive due to the lack of appropriate model systems. Here, we generated BAX/BAK double knockout human-induced pluripotent stem cells (hiPSCs), hiPSC-derived neural progenitor cells (hNPCs), neural rosettes, and cerebral organoids to uncover the effects of BAX and BAK deletion in an in vitro model of early human brain development. We found that BAX and BAK-deficient cells have abnormal mitochondrial morphology and give rise to aberrant cortical structures. We suggest crucial functions for BAX and BAK during human development, including maintenance of homeostatic mitochondrial morphology, which is crucial for proper development of progenitors and neurons of the cortex. Human pluripotent stem cell-derived systems can be useful platforms to reveal novel functions of the apoptotic machinery in neural development.
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Inhibition of focal adhesion kinase increases myofibril viscosity in cardiac myocytes. Cytoskeleton (Hoboken) 2020; 77:342-350. [PMID: 32885903 DOI: 10.1002/cm.21632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 11/06/2022]
Abstract
The coordinated generation of mechanical forces by cardiac myocytes is required for proper heart function. Myofibrils are the functional contractile units of force production within individual cardiac myocytes. At the molecular level, myosin motors form cross-bridges with actin filaments and use ATP to convert chemical energy into mechanical forces. The energetic efficiency of the cross-bridge cycle is influenced by the viscous damping of myofibril contraction. The viscoelastic response of myofibrils is an emergent property of their individual mechanical components. Previous studies have implicated titin-actin interactions, cell-ECM adhesion, and microtubules as regulators of the viscoelastic response of myofibrils. Here we probed the viscoelastic response of myofibrils using laser-assisted dissection. As a proof-of-concept, we found actomyosin contractility was required to endow myofibrils with their viscoelastic response, with blebbistatin treatment resulting in decreased myofibril tension and viscous damping. Focal adhesion kinase (FAK) is a key regulator of cell-ECM adhesion, microtubule stability, and myofibril assembly. We found inhibition of FAK signaling altered the viscoelastic properties of myofibrils. Specifically, inhibition of FAK resulted in increased viscous damping of myofibril retraction following laser ablation. This damping was not associated with acute changes in the electrophysiological properties of cardiac myocytes. These results implicate FAK as a regulator of mechanical properties of myofibrils.
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Abstract
Mitochondrial fission is sustained through contact with several organelles, including the endoplasmic reticulum, lysosomes, and the actin cytoskeleton. Nagashima et al. (2020) now demonstrate that PI(4)P-containing Golgi-derived vesicles also modulate mitochondrial fission, driven by Arf1 and PI(4)KIIIβ activity, identifying a new organelle contact involved in maintaining mitochondrial homeostasis.
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Impaired Mitochondrial Respiration in Hermansky‐Pudlak Syndrome 1‐Defective Alveolar Type 2 Cells is Associated with Enhanced Mitochondrial Fission. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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MCL-1 Inhibition by Selective BH3 Mimetics Disrupts Mitochondrial Dynamics Causing Loss of Viability and Functionality of Human Cardiomyocytes. iScience 2020; 23:101015. [PMID: 32283523 PMCID: PMC7155208 DOI: 10.1016/j.isci.2020.101015] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 02/25/2020] [Accepted: 03/24/2020] [Indexed: 12/17/2022] Open
Abstract
MCL-1 is a well-characterized inhibitor of cell death that has also been shown to be a regulator of mitochondrial dynamics in human pluripotent stem cells. We used cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) to uncover whether MCL-1 is crucial for cardiac function and survival. Inhibition of MCL-1 by BH3 mimetics resulted in the disruption of mitochondrial morphology and dynamics as well as disorganization of the actin cytoskeleton. Interfering with MCL-1 function affects the homeostatic proximity of DRP-1 and MCL-1 at the outer mitochondrial membrane, resulting in decreased functionality of hiPSC-CMs. Cardiomyocytes display abnormal cardiac performance even after caspase inhibition, supporting a nonapoptotic activity of MCL-1 in hiPSC-CMs. BH3 mimetics targeting MCL-1 are promising anti-tumor therapeutics. Progression toward using BCL-2 family inhibitors, especially targeting MCL-1, depends on understanding its canonical function not only in preventing apoptosis but also in the maintenance of mitochondrial dynamics and function. BH3 mimetics targeting MCL-1 disrupt the mitochondrial network of human iPSC-CMs The BH3-mimetic-mediated effects on mitochondrial dynamics are DRP-1-dependent Targeting MCL-1 affects the survival and function of human cardiomyocytes Human iPSC-derived cardiomyocytes can be used to reveal toxicity of MCL-1 inhibitors
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Uncovering cell biology in the third dimension. Mol Biol Cell 2020; 31:319-323. [PMID: 32105584 PMCID: PMC7183789 DOI: 10.1091/mbc.e19-04-0211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 12/24/2019] [Accepted: 01/03/2020] [Indexed: 01/08/2023] Open
Abstract
Developmental biology has long benefited from studies of classic model organisms. These model systems have provided the fundamental understanding of general principles of development, as well as insight into genes and signaling pathways that control unique aspects of cell fate specification and tissue morphogenesis. Because human brain development cannot be studied in vivo, scientists have relied on these model systems to study basic principles underlying the development of this complex organ as many of these genes and signaling pathways play conserved roles in human development. However, recent studies have shown species-specific signatures in neurodevelopment such as the transcriptome of outer-radial glia, suggesting use of a human-derived model remains imperative. Over the past decade, human stem cell-derived brain organoids have emerged as a biologically relevant model system to study normal human brain development and neurological diseases. Here, we provide a historical perspective of this emerging model system, discuss current systems and limitations, and propose that new mechanistic insight into cell biology can be revealed using these three-dimensional brain structures.
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A connection in life and death: The BCL-2 family coordinates mitochondrial network dynamics and stem cell fate. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 353:255-284. [PMID: 32381177 DOI: 10.1016/bs.ircmb.2019.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The B cell CLL/lymphoma-2 (BCL-2) family of proteins control the mitochondrial pathway of apoptosis, also known as intrinsic apoptosis. Direct binding between members of the BCL-2 family regulates mitochondrial outer membrane permeabilization (MOMP) after an apoptotic insult. The ability of the cell to sense stress and translate it into a death signal has been a major theme of research for nearly three decades; however, other mechanisms by which the BCL-2 family coordinates cellular homeostasis beyond its role in initiating apoptosis are emerging. One developing area of research is understanding how the BCL-2 family of proteins regulate development using pluripotent stem cells as a model system. Understanding BCL-2 family-mediated regulation of mitochondrial homeostasis in cell death and beyond would uncover new facets of stem cell maintenance and differentiation potential.
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P789 Reverse left atrial functional remodeling after surgical aortic valve replacement is dependent on impaired left atrial function and reverse left ventricular remodeling. Eur Heart J Cardiovasc Imaging 2020. [DOI: 10.1093/ehjci/jez319.446] [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: 11/13/2022] Open
Abstract
Abstract
Funding Acknowledgements
Fundação Portuguesa para a Ciência e Tecnologia (SFRH/BD/104369/2014) and Sociedade Portuguesa de Cardiologia (“Bolsa de investigação João Porto”)
OnBehalf
EPICHEART Study
Background
Left atrial (LA) functional remodeling is an important mechanism in the pathophysiology of aortic stenosis (AS), and readily-assessable using speckle-tracking echocardiography (STE). It is uncertain whether and how surgical aortic valve replacement (SAVR) affects reverse LA functional remodeling.
Aims
We aimed to evaluate LA functional remodeling post-SAVR using STE and to explore potential underlying mechanisms.
Methods
73 symptomatic severe AS patients (72.6 ± 8.14 years, 53.4% male) were assessed before and six months after SAVR (Fig.1-A). LA function was evaluated using STE-derived LA longitudinal strain during reservoir (LASr), conduit (LAScd) and contraction (LASct) phases (Fig1.-B); reverse LA remodeling was represented by their relative percentual changes. LA structure was assessed by LA area and indexed volume.
Results
LA structure and left ventricle (LV) indexed mass, end-diastolic diameter (LVEDD) and mean E/e" improved after SAVR (Table 1). Although paired-samples analysis did not show significant changes in LA function, multiple linear regression revealed that preoperative LA strain parameters were the sole baseline predictors of reverse LA remodeling: lower baseline LASr, LAScd and LASct were related to improved LASr, LAScd and LASct, respectively (Fig.1-C); mean E/e’ decrease was associated with LAScd improvement (Fig.1-D2). LV mass and LVEDD decrease were not associated with LA functional recovery.
Conclusion
Reverse LA functional remodeling is compromised after SAVR, and increased in patients with impaired baseline LA function. LV diastolic function recovery was linked to improved LA conduit function. An optimal echocardiographic cut-off should be further explored in order to better adjudicate surgical timing, and foster LA functional recovery.
Echocardiographic assessment Baseline 6-months post-SAVR Paired t-test (p-value) Mean aortic gradient (mmHg) 49.6 ± 12.2 11.2 ± 5.1 <0.0001 LA area (cm2) 20.9 ± 4.9 19.5 ± 4.1 0.02 LA indexed volume (mL/m2) 37.4 ± 12.4 30.7 ± 8.3 <0.0001 LASr (%) 30.0 ± 10.4 29.3 ± 11.2 0.57 LAScd (%) 14.3 ± 7.4 14.3 ± 6.8 0.95 LASct (%) 15.6 ± 6.5 15.0 ± 7.2 0.50 LV indexed mass (g/m2) 128.6 ± 31.8 124.5 ± 30.0 <0.0001 LV end-diastolic diameter (mm) 45.7 ± 5.19 44.7 ± 5.7 0.03 LV ejection fraction (%) 66.0 ± 6.0 64.6 ± 5.5 0.54 Mean E/e´ ratio 14.2 ± 5.5 11.2 ± 4.3 0.0004 Values are mean ± SD
Abstract P789 Figure. Left atrial remodeling after SAVR
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Abstract
Juxtaglomerular (JG) cells, major sources of renin, differentiate from metanephric mesenchymal cells that give rise to JG cells or a subset of smooth muscle cells of the renal afferent arteriole. During periods of dehydration and salt deprivation, renal mesenchymal stromal cells (MSCs) differentiate from JG cells. JG cells undergo expansion and smooth muscle cells redifferentiate to express renin along the afferent arteriole. Gene expression profiling comparing resident renal MSCs with JG cells indicates that the transcription factor Sox6 is highly expressed in JG cells in the adult kidney. In vitro, loss of Sox6 expression reduces differentiation of renal MSCs to renin-producing cells. In vivo, Sox6 expression is upregulated after a low-Na+ diet and furosemide. Importantly, knockout of Sox6 in Ren1d+ cells halts the increase in renin-expressing cells normally seen during a low-Na+ diet and furosemide as well as the typical increase in renin. Furthermore, Sox6 ablation in renin-expressing cells halts the recruitment of smooth muscle cells along the afferent arteriole, which normally express renin under these conditions. These results support a previously undefined role for Sox6 in renin expression.
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Spin∞: an updated miniaturized spinning bioreactor design for the generation of human cerebral organoids from pluripotent stem cells. HARDWAREX 2019; 6:e00084. [PMID: 32864515 PMCID: PMC7451502 DOI: 10.1016/j.ohx.2019.e00084] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Three-dimensional (3D) brain organoids derived from human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs), have become a powerful system to study early development events and to model human disease. Cerebral organoids are generally produced in static culture or in a culture vessel with active mixing, and the two most widely used systems for mixing are a large spinning flask and a miniaturized multi-well spinning bioreactor (also known as Spin Omega (SpinΩ)). The SpinΩ provides a system that is amenable to drug testing, has increased throughput and reproducibility, and utilizes less culture media. However, technical limitations of this system include poor stability of select components and an elevated risk of contamination due to the inability to sterilize the device preassembled. Here, we report a new design of the miniaturized bioreactor system, which we term Spinfinity (Spin∞) that overcomes these concerns to permit long-term experiments. This updated device is amenable to months-long (over 200 days) experiments without concern of unexpected malfunctions.
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Abstract
Research in the stem cell field has traditionally focused on understanding key transcriptional factors that provide pluripotent cell identity. However, much less is known about other critical non-transcriptional signaling networks that govern stem cell identity. Although we continue to gain critical insights into the mechanisms underlying mitochondrial morphology and function during cellular reprogramming – the process of reverting the fate of a differentiated cell into a stem cell, many uncertainties remain. Recent studies suggest an emerging landscape in which mitochondrial morphology and function have an active role in maintaining and regulating changes in cell identity. In this review, we will focus on these emerging concepts as crucial modulators of cellular reprogramming. Recognition of the widespread applicability of these concepts will increase our understanding of the mitochondrial mechanisms involved in cell identity, cell fate and disease.
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31
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Computational Immune Monitoring Reveals Abnormal Double-Negative T Cells Present across Human Tumor Types. Cancer Immunol Res 2018; 7:86-99. [PMID: 30413431 DOI: 10.1158/2326-6066.cir-17-0692] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 07/17/2018] [Accepted: 11/05/2018] [Indexed: 12/22/2022]
Abstract
Advances in single-cell biology have enabled measurements of >40 protein features on millions of immune cells within clinical samples. However, the data analysis steps following cell population identification are susceptible to bias, time-consuming, and challenging to compare across studies. Here, an ensemble of unsupervised tools was developed to evaluate four essential types of immune cell information, incorporate changes over time, and address diverse immune monitoring challenges. The four complementary properties characterized were (i) systemic plasticity, (ii) change in population abundance, (iii) change in signature population features, and (iv) novelty of cellular phenotype. Three systems immune monitoring studies were selected to challenge this ensemble approach. In serial biopsies of melanoma tumors undergoing targeted therapy, the ensemble approach revealed enrichment of double-negative (DN) T cells. Melanoma tumor-resident DN T cells were abnormal and phenotypically distinct from those found in nonmalignant lymphoid tissues, but similar to those found in glioblastoma and renal cell carcinoma. Overall, ensemble systems immune monitoring provided a robust, quantitative view of changes in both the system and cell subsets, allowed for transparent review by human experts, and revealed abnormal immune cells present across multiple human tumor types.
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A comparative study of electronic stethoscopes for cardiac auscultation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2017:2610-2613. [PMID: 29060434 DOI: 10.1109/embc.2017.8037392] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
There are several electronic stethoscopes available on the market today, with a very high potential for healthcare namely telemedicine, assisted decision and education. However, there are no recent comparatives studies published about the recording quality of auscultation sounds. In this study we aim to: a) define a ranking, according to experts opinion of 6 of the most relevant electronic stethoscopes on the market today; b) verify if there are any relations between a stethoscope's performance and the type of pathology present; c) analyze if some pathologies are more easily identified than others when using electronic auscultation. Our methodology consisted in creating two study groups: the first group included 18 cardiologists and cardiology house officers, acting as the gold standard of this work. The second included 30 medical students. Using a database of heart sounds recorded in real hospital environments, we applied questionnaires to observers from each group. The first group listened to 60 cardiac auscultations recorded by the 6 stethoscopes, and each one was asked to identify the pathological sound present: aortic stenosis, mitral regurgitation or normal. The second group was asked to choose, between two auscultation recordings, using as criteria the best sound quality for the identification of pathological sounds. Results include a total of 1080 evaluations, in which 72% of cases were correctly diagnosed. A detailed breakdown of these results is presented in this paper. As conclusions, results showed that the impact of the differences between stethoscopes is very small, given that we did not find statistically significant differences between all pairs of stethoscopes. Normal sounds showed to be easier to identify than pathological sounds, but we did not find differences between stethoscopes in this identification.
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P4682Myocardial deformation in hypertrophic cardiomyopathy: association with ventricular arrhythmias. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p4682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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35
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P2796Percutaneous treatment of severe mitral regurgitation with mitraclip device: potential role of NT-proBNP in prognosis assessment. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p2796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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P3601Pre-existent vs. new-onset atrial fibrillation after transcatheter aortic valve implantation: predictors and outcomes. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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57Impact of cardiac rehabilitation programs among myocardial infarction survivors not undergoing revascularization. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P4210Impact of myocardial fibrosis in left ventricular remodeling after aortic valve replacement (AVR) for severe aortic stenosis (AS). Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p4210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Background
Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.
Methods and Results
A random subcohort of 349 participants was selected from the
DCCT
/
EDIC
(Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from
DCCT
baseline, year 1, and closeout of
DCCT
, and 1 to 2 years post‐
DCCT
(
EDIC
years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F
2α
isoprostanes, and its metabolite, 2,3 dinor‐8
iso
prostaglandin F
2α
. Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8
iso
prostaglandin F
2α
, an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase,
P
<0.003; −5.3% risk for 10% higher 2,3 dinor‐8
iso
prostaglandin F
2α
,
P
=0.0092). In contrast, the oxidative markers myeloperoxidase and F
2α
isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between
DCCT
intensive and conventional treatment groups in the change in all biomarkers across time segments.
Conclusions
Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.
Clinical Trial Registration
URL
:
https://www.clinicaltrials.gov
. Unique identifiers:
NCT
00360815 and
NCT
00360893.
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Wnt Signaling and Its Impact on Mitochondrial and Cell Cycle Dynamics in Pluripotent Stem Cells. Genes (Basel) 2018; 9:genes9020109. [PMID: 29463061 PMCID: PMC5852605 DOI: 10.3390/genes9020109] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/17/2022] Open
Abstract
The core transcriptional network regulating stem cell self-renewal and pluripotency remains an intense area of research. Increasing evidence indicates that modified regulation of basic cellular processes such as mitochondrial dynamics, apoptosis, and cell cycle are also essential for pluripotent stem cell identity and fate decisions. Here, we review evidence for Wnt regulation of pluripotency and self-renewal, and its connections to emerging features of pluripotent stem cells, including (1) increased mitochondrial fragmentation, (2) increased sensitivity to cell death, and (3) shortened cell cycle. We provide a general overview of the stem cell–specific mechanisms involved in the maintenance of these uncharacterized hallmarks of pluripotency and highlight potential links to the Wnt signaling pathway. Given the physiological importance of stem cells and their enormous potential for regenerative medicine, understanding fundamental mechanisms mediating the crosstalk between Wnt, organelle-dynamics, apoptosis, and cell cycle will be crucial to gain insight into the regulation of stemness.
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A Non-apoptotic Function of MCL-1 in Promoting Pluripotency and Modulating Mitochondrial Dynamics in Stem Cells. Stem Cell Reports 2018; 10:684-692. [PMID: 29429957 PMCID: PMC5918190 DOI: 10.1016/j.stemcr.2018.01.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 01/15/2023] Open
Abstract
Human pluripotent stem cells (hPSCs) maintain a highly fragmented mitochondrial network, but the mechanisms regulating this phenotype remain unknown. Here, we describe a non-cell death function of the anti-apoptotic protein, MCL-1, in regulating mitochondrial dynamics and promoting pluripotency of stem cells. MCL-1 is induced upon reprogramming, and its inhibition or knockdown induces dramatic changes to the mitochondrial network as well as loss of the key pluripotency transcription factors, NANOG and OCT4. Aside from localizing at the outer mitochondrial membrane like other BCL-2 family members, MCL-1 is unique in that it also resides at the mitochondrial matrix in pluripotent stem cells. Mechanistically, we find MCL-1 to interact with DRP-1 and OPA1, two GTPases responsible for remodeling the mitochondrial network. Depletion of MCL-1 compromised the levels and activity of these key regulators of mitochondrial dynamics. Our findings uncover an unexpected, non-apoptotic function for MCL-1 in the maintenance of mitochondrial structure and stemness. Downregulation or inhibition of MCL-1 causes loss of OCT4 and NANOG expression MCL-1 downregulation or inhibition causes elongation of the mitochondrial network MCL-1 binds and modulates DRP-1 and OPA1 expression and activity Interactions between MCL-1 and DRP-1/OPA1 are disrupted by MCL-1 inhibitor
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Apical polarization and lumenogenesis: The apicosome sheds new light. J Cell Biol 2017; 216:3891-3893. [PMID: 29138252 PMCID: PMC5716292 DOI: 10.1083/jcb.201710028] [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] [Indexed: 11/22/2022] Open
Abstract
Romero-Morales et al. preview work from the Taniguchi et al. describing the role of a new structure, the apicosome, in lumenogenesis. Establishment of apico–basal polarity is critical for the lumenal epiblast-like morphogenesis of human pluripotent stem cells (hPSCs). In this issue, Taniguchi et al. (2017. J Cell Biol.https://doi.org/10.1083.jcb201704085) describe a structure called the apicosome, generated in single hPSCs, that allows them to self-organize and form the lumenal epiblast-like stage.
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P4500Late gadolinium enhancement distribution assessed by magnetic resonance and arrhythmogenic risk in patients with hypertrophic cardiomyopathy. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx504.p4500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P6391Impact of transcatheter aortic valve implantation on cardiac electrical conduction: the “all or nothing” effect? Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx493.p6391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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The Molecular Basis for the Lack of Inflammatory Responses in Mouse Embryonic Stem Cells and Their Differentiated Cells. THE JOURNAL OF IMMUNOLOGY 2017; 198:2147-2155. [PMID: 28130495 DOI: 10.4049/jimmunol.1601068] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 12/30/2016] [Indexed: 12/12/2022]
Abstract
We reported previously that mouse embryonic stem cells do not have a functional IFN-based antiviral mechanism. The current study extends our investigation to the inflammatory response in mouse embryonic stem cells and mouse embryonic stem cell-differentiated cells. We demonstrate that LPS, TNF-α, and viral infection, all of which induce robust inflammatory responses in naturally differentiated cells, failed to activate NF-κB, the key transcription factor that mediates inflammatory responses, and were unable to induce the expression of inflammatory genes in mouse embryonic stem cells. Similar results were obtained in human embryonic stem cells. In addition to the inactive state of NF-κB, the deficiency in the inflammatory response in mouse embryonic stem cells is also attributed to the lack of functional receptors for LPS and TNF-α. In vitro differentiation can trigger the development of the inflammatory response mechanism, as indicated by the transition of NF-κB from its inactive to active state. However, a limited response to TNF-α and viral infection, but not to LPS, was observed in mouse embryonic stem cell-differentiated fibroblasts. We conclude that the inflammatory response mechanism is not active in mouse embryonic stem cells, and in vitro differentiation promotes only partial development of this mechanism. Together with our previous studies, the findings described in this article demonstrate that embryonic stem cells are fundamentally different from differentiated somatic cells in their innate immunity, which may have important implications in developmental biology, immunology, and embryonic stem cell-based regenerative medicine.
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Moderated Posters session: cardiovascular magnetic resonanceP967Simplified segmental calculation of extracellular volume with T1 mapping for evaluation of diffuse interstitial fibrosisP968Diffuse myocardial fibrosis quantification by magnetic resonance imaging in patients with aortic valve diseasesP969Occult anthracycline cardiac injury in adolescents and young adults cancer survivors with normal left ventricular ejection fractionP970Reference values for regional and global myocardial T2 mapping with cardiovascular magnetic resonance at 1.5T vs 3TP971The accuracy of a real-time MR method in the assessment of right ventricular volume and functionP972Can blunted heart rate response to adenosine vasodilator stress have prognostic implications on myocardial perfusion imaging by cardiovascular magnetic resonance?P973Association of vitamin d with left atrial fibrosis in patients with lone AF undergoing cryoablationP974Left ventricular remodelling after mitral valve reconstruction: a 1-year prospective cMRI studyP975Abnormal regional myocardial motion in patients with left ventricular pressure overload detected by MR tissue phase mapping at rest and during stressP976Potential utility of splenic switch-off to improve the diagnostic performance of vasodilator stress cardiac magnetic resonance. Preliminary study. Eur Heart J Cardiovasc Imaging 2015. [DOI: 10.1093/ehjci/jev273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Poster session 5The imaging examinationP1097Correlation between visual and quantitative assessment of left ventricle: intra- and inter-observer agreementP1099Incremental prognostic value of late gadolinium-enhanced by cardiac magnetic resonance in patients with heart failureAnatomy and physiology of the heart and great vesselsP1100Left ventricular geometry and diastolic performance in erectile dysfunction patients; a topic of differential arterial stiffness influenceAssessment of diameters, volumes and massP1101Impact of the percutaneous closure of atrial septal defect on the right heart "remodeling"P1102Left Ventricular Mass Indexation in Infants, Children and Adolescents: a Simplified Approach for the Identification of Left Ventricular Hypertrophy in Clinical PracticeP1103Impact of trabecules while quantifying cardiac magnetic resonance exams in patients with systemic right ventricleP1104Detection of subclinical atherosclerosis by carotid intima-media thickness: correlation with leukocytes telomere shorteningAssessments of haemodynamicsP1105Flow redirection towards the left ventricular outflow tract: vortex formation is not affected by variations in atrio-ventricular delayAssessment of systolic functionP1106Reproducibility and feasibility of cardiac MRI feature tracking in Fabry diseaseP1107Normal left ventricular strain values by two-dimensional strain echocardiography; result of normal (normal echocardiographic dimensions and functions in korean people) studyP1108Test-retest repeatability of global strain following st-elevation myocardial infarction - a comparison of tagging and feature trackingP1109Cardiotoxicity induced by tyrosine kinase inhibitors in patients with gastrointestinal stromal tumors (GIST)P1110Finite strain ellipses for the analysis of left ventricular principal strain directions using 3d speckle tracking echocardiographyP1111Antihypertensive therapy reduces time to peak longitudinal strainP1112Right ventricular systolic function as a marker of prognosis after inferior myocardial infarction - 5-year follow-upP1113Is artery pulmonary dilatation related with right but also early left ventricle dysfunction in pulmonary artery hypertension?P1114Right ventricular mechanics changes according to pressure overload increasing, a 2D-speckle tracking echocardiographic evaluationAssessment of diastolic functionP1115Paired comparison of left atrial strain from P-wave to P-wave and R-wave to R-waveP1116Diagnostic role of Tissue Doppler Imaging echocardiographic criteria in obese heart failure with preserved ejection fraction patientsP1117Evaluation of diastolic function of right ventricle in idiopathic pulmonary arterial hypertensionP1118Severity and predictors of diastolic dysfunction in a non-hypertensive non-ischemic cohort of Egyptian patients with documented systemic autoimmune disease; pilot reportP1119correlation between ST segment shift and cardiac diastolic function in patients with acute myocardial infarctionIschemic heart diseaseP1120Computed tomography coronary angiography verSus sTRess cArdiac magneTic rEsonance for the manaGement of sYmptomatic revascularized patients: a cost effectiveness study (STRATEGY study)P1121Utility of transmural myocardial mechanic for early infarct size prediction after primary percutaneous coronary intervention in STEMI patientsP1122Progressive Improvements of the echocardiographic deformation parameters in ST Elevation Myocardial Infarction after five years follow-upP1123Long-term prognostic value of left ventricular dyssynchrony as assessed by cardiac magnetic resonance feature-tracking imaging after a first st-segment elevation myocardial infarctionP1124Differences in mitral annulus remodeling in acute anterior ST elevation and acute inferior ST elevation myocardial infarctionP1125Reduction of microvascular injury using a novel theragnostic ultrasound strategy: a first in men feasibility and safety studyP1126Impact of focused echocardiography in clinical decision of patient presented with st elevation myocardial infarction underwent primary angioplastyHeart valve DiseasesP1127Aortic valve area calculation in aortic stenosis: a comparison among conventional and 3D-transesophageal echocardiography and computed tomographyP1128Myocardial fibrosis and microRNA-21 expression in patients with severe aortic valve stenosis and preserved ejection fraction: a 2D speckle tracking echocardiography, tissutal and plasmatic studyP1129Quantification of calcium amount in a new experimental model: a comparison between calibrated integrated backscatter of ultrasound and computed tomographyP1130Altered diffusion capacity in aortic stenosis: role of the right heartP1131Osteoprotegerin predicts all-cause mortality in calcific aortic stenosis patients with preserved left ventricle ejection fraction in long term observationP1132Mitral regurgitation as a risk factor for pulmonary hypertension in patients with aortic stenosisP1133The relationship between the level of plasma B-type natriuretic peptide and mitral stenosisP1134Aortic regurgitation, left ventricle mechanics and vascular load: a single centre 2d derived-speckle tracking studyP1135Feasibility and reproducibility issues limit the usefulness of quantitative colour Doppler parameters in the assessment of chronic aortic and mitral regurgitation severityP1136Predictors of postoperative outcome in degenerative mitral regurgitationP1137Left ventricular mechanical dyssynchrony in patients with severe mitral regurgitation of rheumatic etiology; three dimensional echocardiography studyP1138Functional mitral regurgitation and left atrial dysfunction concur in determining pulmonary hypertension and functional status in subjects with left ventricular systolic dysfunctionP11393D echocardiography allows more effective quantitative assessment of the severity of functional tricuspid regurgitation than conventional 2D/Doppler echocardiographyP1140Prosthetic valve thrombosis: still a severe disease? 10-years experience in a university hospitalP1141Validity of echocardiography in the hospital course of patients with feverP1142Do baseline 3DTEE characteristics of mitral valve apparatus predict long term result in patients undergoing percutaneous valve repair for degenerative regurgitation?P1143Influence of baseline aortic regurgitation on mitral regurgitation change after transcatheter aortic valve replacement for aortic stenosisP1144Prevalence of echocardiography detected significant valvular regurge in subclinical rheumatic carditis in assiut childrenCardiomyopathiesP1145Can we early detect left ventricular systolic dysfunction in patients with Duchenne muscular dystrophy using global longitudinal strain assessment?P1146Prevalence of isolated papillary muscle hypertrophy in young competitive athletesP1147Troponin release after exercise in patients with hypertrophic cardiomyopathy: associations with clinical and mr imaging characteristicsP1148Atrial fibrillation in hypertrophic cardiomyopathy: can we score the risk?P1149Impact of hypertrophy on multiple layer longitudinal deformation in hypertrophy cardiomyopathy and cardiac amyloidosis compared to controlsP1150Functional evaluation in hypertrophic cardiomyopathy combining cardiopulmonary exercise testing combined with exercise-echocardiographyP1151Refinement of the old diagnostic criteria of left ventricular noncompaction cardiomyopathy (LVNC) based on cardiac magnetic resonance (CMR)P1152Differences of clinical characteristics and outcomes between acute myocarditis with preserved and reduced left ventricular systolic functionP1153Value of longitudinal strain for distinguishing left ventricular non-compaction from idiopathic dilated cardiomyopathyP1154Speed of recovery of left ventricular function is not related to the prognosis of Takotsubo cardiomyopathy. A Portuguese multicentre studyP1155Predictors of in-hospital left ventricular systolic function recovery after admission with takotsubo cardiomyopathy. Portuguese multicentre studyP1156Mid-ventricular takotsubo detected by initial echocardiogram associates with recurrence of takotsubo cardiomyopathy - a portuguese multicentre studySystemic diseases and other conditionsP1157Relations between left ventricle remodelling and expression of angiotensin 2 AT2R1 geneP1158Impact of renal denervation on long-term blood pressure variability and surrogate markers of target organ damage in individuals with drug-resistant arterial hypertensionP1159Greater improvement of coronary artery function, left ventricular deformation and twisting by IL12/23 compared to TNF-a inhibition in psoriasisP1160Advanced glycation end products play a role in adverse LV remodeling following MIP1161Incidence of subclinical myocardial dysfunction in patients with systemic sclerosis and normal left ventricular systolic and diastolic functionP1162Left atrial remodeling and dysfunction occur early in patients with systemic sclerosis and normal left ventricular functionP1163Intrinsic vortex formation : a unique performance indicatorP1164P-wave morphology is unaffected by training-induced biatrial dilatation: a prospective, longitudinal study in healthy athletesP1165Usefulness of transthoracic echocardiography in diagnosis of young patients with ischemic strokeP1166Primary cardiac lymphoma: role of echocardiography in the clinical managementP1167Abnormal echocardiographic findings in cancer patients before chemotherapyMasses, tumors and sources of embolismP1168Three-dimensional transesophageal echocardiography of the left atrial appendage reduces rate of postpone electrical cardioversionP1169Detection of ventricular thrombus by cmr after reperfused st-segment elevation myocardial infarction correlated with echocardiographyP1170Clinical and transthoracic echocardiographic predictors of left atrial appendage thrombus in patients with atrial fibrillationStress echocardiographyP1171Pharmacological stress echocardiography complications: a 4-year single center experienceP1172Myocardial functional and perfusion reserve in type I diabetesP1173Feasibility of incorporating 3D Dobutamine stress echocardiography into routine clinical practiceP1174Right ventricular isovolumic acceleration at rest and during exercise in children after heart transplantP1175Right ventricular systolic and diastolic response to exercise in children after heart transplant -a bicycle exercise studyP1176Determinants of functional capacity in heart failure patients with reduced ejection fractionP1177Handgrip stress echocardiography with emotional component compared to conventional isometric exercise in coronary artery disease diagnosisP1178The relationship between resting transthoracic echocardiography and exercise capacity in patients with paroxysmal atrial fibrillationP1179Correlation between NT-proBNP and selected echocardiography parameters at rest and after exercise in patients with functional ischemic mitral regurgitation qualified for cardiosurgical treatmentReal-time three-dimensional TEEP1180Vena contracta area for severity grading in functional and degenerative mitral regurgitation: A study based on transesophageal 3D colour Doppler in 419 patientsP1181Proximal flow convergence by 3D echocardiography in the evaluation of mitral valve area in rheumatic mitral stenosisP1182Quantification of valve dimensions by transesophageal 3D echocardiography in patients with functional and degenerative mitral regurgitationTissue Doppler and speckle trackingP1183Automatic calculation of left ventricular volume changes over a cardiac cycle from echocardiography images by nonlinear dimensionality reductionP1184Effect of the mitral valve repairs on the left ventricular blood flow formationP1185Quantification of left atrial strain using cardiovascular magnetic resonance. a comparison between hypertrophic cardiomyopathy and healthy controlsP1186The role of early systolic lengthening in patients with non-ST elevation acute coronary syndrome and its relation to syntax scoreP1187Different standard two dimensional strain methods to quantity left ventricular mechanicsP1188Atrial function and electrocardiography caracteristics in sportsmen with or without paroxysmal atrial fibrillationP1189Right ventricular outflow premature contractions induce regional left ventricular dysfunctionP1190Ultrasound guided venous access for pacemaker and defibrillators. Randomized TrialP1191Atrial function analysis correlates with symptoms and quality of life of heart failure patientsP1192The use of tissue doppler echocardiography in myocardial iron overload in patients with thalassaemia majorP1193Independent association between pulse pressure and left ventricular global longitudinal strainP1194Global and regional longitudinal strain identifies the presence of coronary artery disease in patients with suspected reduction of coronary flow reserve and absence of wall motion abnormalitiesP1195Prognostic value of invasive and noninvasive parameters of right ventricular function in patients with pulmonary arterial hypertension receiving specific vasodilator therapyP1196Myocardial deformation analysis to improve arrhythmic risk stratificationP1197Quantitative assessment of regional systolic and diastolic function parameters for detecting prior transient ischemia in normokinetic segmentsP1198Left atrial function in patients with corrected tetralogy of Fallot - a three-dimensional speckle-tracking echocardiographic studyP1199Left atrial ejection force correlates with left atrial strain and volume-based functional properties as assessed by three-dimensional speckle tracking echocardiographyP1200Acute angulation of the aortic arch late after the arterial switch operation for transposition of the great arteries: impact on cardiac mechanicsP1201Circumferential deformation of the ascending thoracic aorta in hypertensive patients by three-dimensional speckle tracking echocardiographyCardiac Magnetic ResonanceP1202The incremental value of cardiac magnetic resonance on diagnosis myocardial infarction and non-obstructed coronary arteriesP1204Reference ranges of global and regional myocardial T1 values derived from MOLLI and shMOLLI at 3TComputed Tomography & Nuclear CardiologyP1205Deformation of the left atrial appendage after percutaneous closure with the Amplatzer cardiac plugP1206Prognostic impact of non-obstructive coronary artery disease on coronary computed tomographic angiography: A single-center study. Eur Heart J Cardiovasc Imaging 2015. [DOI: 10.1093/ehjci/jev275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Erratum: Bax deficiency prolongs cerebellar neurogenesis, accelerates medulloblastoma formation and paradoxically increases both malignancy and differentiation. Oncogene 2015; 34:3881. [DOI: 10.1038/onc.2015.204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
In this and a recent issue of Molecular Cell, Liu et al. (2015) and Ichim et al. (2015) report that low levels of caspase activity triggered by limited mitochondrial outer membrane permeabilization (MOMP) promote genomic instability that drives tumorigenesis, providing a novel and unexpected link between these effectors of apoptosis and cancer initiation.
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The E3 ligase PARC mediates the degradation of cytosolic cytochrome c to promote survival in neurons and cancer cells. Sci Signal 2014; 7:ra67. [PMID: 25028717 DOI: 10.1126/scisignal.2005309] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ability to withstand mitochondrial damage is especially critical for the survival of postmitotic cells, such as neurons. Likewise, cancer cells can also survive mitochondrial stress. We found that cytochrome c (Cyt c), which induces apoptosis upon its release from damaged mitochondria, is targeted for proteasome-mediated degradation in mouse neurons, cardiomyocytes, and myotubes and in human glioma and neuroblastoma cells, but not in proliferating human fibroblasts. In mouse neurons, apoptotic protease-activating factor 1 (Apaf-1) prevented the proteasome-dependent degradation of Cyt c in response to induced mitochondrial stress. An RNA interference screen in U-87 MG glioma cells identified p53-associated Parkin-like cytoplasmic protein (PARC, also known as CUL9) as an E3 ligase that targets Cyt c for degradation. The abundance of PARC positively correlated with differentiation in mouse neurons, and overexpression of PARC reduced the abundance of mitochondrially-released cytosolic Cyt c in various cancer cell lines and in mouse embryonic fibroblasts. Conversely, neurons from Parc-deficient mice had increased sensitivity to mitochondrial damage, and neuroblastoma or glioma cells in which PARC or ubiquitin was knocked down had increased abundance of mitochondrially-released cytosolic Cyt c and decreased viability in response to stress. These findings suggest that PARC-mediated ubiquitination and degradation of Cyt c is a strategy engaged by both neurons and cancer cells to prevent apoptosis during conditions of mitochondrial stress.
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