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STIM2 variants regulate Orai1/TRPC1/TRPC4-mediated store-operated Ca 2+ entry and mitochondrial Ca 2+ homeostasis in cardiomyocytes. Cell Calcium 2024; 119:102871. [PMID: 38537434 DOI: 10.1016/j.ceca.2024.102871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 02/29/2024] [Accepted: 03/07/2024] [Indexed: 04/05/2024]
Abstract
The stromal interaction molecules (STIMs) are the sarcoplasmic reticulum (SR) Ca2+ sensors that trigger store-operated Ca2+ entry (SOCE) in a variety of cell types. While STIM1 isoform has been the focus of the research in cardiac pathophysiology, the function of the homolog STIM2 remains unknown. Using Ca2+ imaging and patch-clamp techniques, we showed that knockdown (KD) of STIM2 by siRNAs increased SOCE and the ISOC current in neonatal rat ventricular cardiomyocytes (NRVMs). Within this cardiomyocyte model, we identified the transcript expression of Stim2.1 and Stim2.2 splice variants, with predominance for Stim2.2. Using conventional and super-resolution confocal microscopy (STED), we found that exogenous STIM2.1 and STIM2.2 formed pre-clusters with a reticular organization at rest. Following SR Ca2+ store depletion, some STIM2.1 and STIM2.2 clusters were translocated to SR-plasma membrane (PM) junctions and co-localized with Orai1. The overexpression strategy revealed that STIM2.1 suppressed Orai1-mediated SOCE and the ISOC current while STIM2.2 enhanced SOCE. STIM2.2-enhanced SOCE was also dependent on TRPC1 and TRPC4. Even if STIM2 KD or splice variants overexpression did not affect cytosolic Ca2+ cycling, we observed, using Rhod-2/AM Ca2+ imaging, that Orai1 inhibition or STIM2.1 overexpression abolished the mitochondrial Ca2+ (mCa2+) uptake, as opposed to STIM2 KD. We also found that STIM2 was present in the mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) by interacting with the inositol trisphosphate receptors (IP3Rs), voltage-dependent anion channel (VDAC), mitochondrial Ca2+ uniporter (MCU), and mitofusin-2 (MNF2). Our results suggested that, in NRVMs, STIM2.1 constitutes the predominant functional variant that negatively regulates Orai1-generated SOCE. It participates in the control of mCa2+ uptake capacity possibly via the STIM2-IP3Rs-VDAC-MCU and MNF2 complex.
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EPAC1 inhibition protects the heart from doxorubicin-induced toxicity. eLife 2023; 12:e83831. [PMID: 37551870 PMCID: PMC10484526 DOI: 10.7554/elife.83831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 08/03/2023] [Indexed: 08/09/2023] Open
Abstract
Anthracyclines, such as doxorubicin (Dox), are widely used chemotherapeutic agents for the treatment of solid tumors and hematologic malignancies. However, they frequently induce cardiotoxicity leading to dilated cardiomyopathy and heart failure. This study sought to investigate the role of the exchange protein directly activated by cAMP (EPAC) in Dox-induced cardiotoxicity and the potential cardioprotective effects of EPAC inhibition. We show that Dox induces DNA damage and cardiomyocyte cell death with apoptotic features. Dox also led to an increase in both cAMP concentration and EPAC1 activity. The pharmacological inhibition of EPAC1 (with CE3F4) but not EPAC2 alleviated the whole Dox-induced pattern of alterations. When administered in vivo, Dox-treated WT mice developed a dilated cardiomyopathy which was totally prevented in EPAC1 knock-out (KO) mice. Moreover, EPAC1 inhibition potentiated Dox-induced cell death in several human cancer cell lines. Thus, EPAC1 inhibition appears as a potential therapeutic strategy to limit Dox-induced cardiomyopathy without interfering with its antitumoral activity.
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The role of hyperglycaemia in the development of diabetic cardiomyopathy. Arch Cardiovasc Dis 2021; 114:748-760. [PMID: 34627704 DOI: 10.1016/j.acvd.2021.08.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 01/08/2023]
Abstract
Diabetes mellitus is a metabolic disorder with a chronic hyperglycaemic state. Cardiovascular diseases are the primary cause of mortality in patients with diabetes. Increasing evidence supports the existence of diabetic cardiomyopathy, a cardiac dysfunction with impaired cardiac contraction and relaxation, independent of coronary and/or valvular complications. Diabetic cardiomyopathy can lead to heart failure. Several preclinical and clinical studies have aimed to decipher the underlying mechanisms of diabetic cardiomyopathy. Among all the co-factors, hyperglycaemia seems to play an important role in this pathology. Hyperglycaemia has been shown to alter cardiac metabolism and function through several deleterious mechanisms, such as oxidative stress, inflammation, accumulation of advanced glycated end-products and upregulation of the hexosamine biosynthesis pathway. These mechanisms are responsible for the activation of hypertrophic pathways, epigenetic modifications, mitochondrial dysfunction, cell apoptosis, fibrosis and calcium mishandling, leading to cardiac stiffness, as well as contractile and relaxation dysfunction. This review aims to describe the hyperglycaemic-induced alterations that participate in diabetic cardiomyopathy, and their correlation with the severity of the disease and patient mortality, and to provide an overview of cardiac outcomes of glucose-lowering therapy.
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ESC working group on cardiac cellular electrophysiology position paper: relevance, opportunities, and limitations of experimental models for cardiac electrophysiology research. Europace 2021; 23:1795-1814. [PMID: 34313298 DOI: 10.1093/europace/euab142] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias are a major cause of death and disability. A large number of experimental cell and animal models have been developed to study arrhythmogenic diseases. These models have provided important insights into the underlying arrhythmia mechanisms and translational options for their therapeutic management. This position paper from the ESC Working Group on Cardiac Cellular Electrophysiology provides an overview of (i) currently available in vitro, ex vivo, and in vivo electrophysiological research methodologies, (ii) the most commonly used experimental (cellular and animal) models for cardiac arrhythmias including relevant species differences, (iii) the use of human cardiac tissue, induced pluripotent stem cell (hiPSC)-derived and in silico models to study cardiac arrhythmias, and (iv) the availability, relevance, limitations, and opportunities of these cellular and animal models to recapitulate specific acquired and inherited arrhythmogenic diseases, including atrial fibrillation, heart failure, cardiomyopathy, myocarditis, sinus node, and conduction disorders and channelopathies. By promoting a better understanding of these models and their limitations, this position paper aims to improve the quality of basic research in cardiac electrophysiology, with the ultimate goal to facilitate the clinical translation and application of basic electrophysiological research findings on arrhythmia mechanisms and therapies.
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Functional study of a N-terminal CPVT mutation RyR2R420Q in patient specific hiPSC-CMs model. Europace 2021. [DOI: 10.1093/europace/euab116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ANR (Agence Nationale de la Rercherche)
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal genetic arrhythmia that manifests by syncope or sudden death in children and young adults under stress conditions without obvious cardiac structural abnormality. A novel CPVT mutation located in the RyR2 N terminal portion has been identified in a Spanish family (RyR2R420Q). According to the studies of RyR2 function in HEK293 cell line, this mutation presented gain of function at low cytosolic intracellular Ca2+ concentration ([Ca2+]i) and loss of function at high [Ca2+]i. Moreover, KI mice heterozygous for this mutation presented bradycardia and sino-atrial node (SAN) dysfunction. Here we generated induced pluripotent stem cell (hiPSC) from two brothers (one with mutation, the other without mutation as control) of this family and differentiated them into cardiomyocytes (hiPSC-CM). In order to verify that the differentiated cells were well cardiomyocytes, we did immunofluorescence labelling to detect the α-actinin expression and found that around 90% cells were α-actinin positive in both groups of hiPS-CMs. Then the calcium transient was studied by confocal microscopy and the action potential (AP) by micro-electrode technique. The characteristics of spontaneous AP of mutated cells were mostly similar to that of control cells, but more mutated cells presented proarrhythmic behaviors under adrenergic stimulation. hiPSC-CM are immature cardiomyocytes and contract spontaneously. In order to be able to analyze [Ca2+]i transient characteristics, we paced the cells at a constant rate of 1 Hz by field stimulation through two Pt electrodes. Sarcoplasmic reticulum (SR) Ca2+ load was estimated by rapid caffeine (10 mM) application. hiPSC-CMs from the RyR2R420Q carrier presented smaller SR Ca2+ load than those from the control person, whereas their fractional release (the [Ca2+]i transient normalized by the amount of Ca2+ stored in the SR) was higher than that in control group, indicating a gain-of-function mutation. Even if SR Ca2+ load was smaller in RyR2R420Q cells, they often presented proarrhythmogenic behavior such as Ca2+ waves. The fact was further enhanced during β-adrenergic stimulation, pointing to this model as a valuable tool to study the CPVT disease in human cells.
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Ca2+ handling in induced-pluripotent cardiomyocytes from female CPVT patient, and comparison to male. Europace 2021. [DOI: 10.1093/europace/euab116.536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Agence Nationale de la Recherche
Introduction
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is an inherited disease manifested as syncope or sudden death in apparently healthy children or young adults, in the absence of structural cardiac disease. The ryanodine receptor (RyR2) R420Q mutation was identified in a Spanish 14-year-old boy who died suddenly due to emotional stress. We generated human induced-pluripotent (h-iPS) derived cardiomyocytes from two brothers (see Yin’s poster in this meeting). As most of sudden death occurs in males, we had the hypothesis that there might be some sex-dependent differences.
Purpose and methods
We aim to elucidate the key role of [Ca2+]i in the genesis of cardiac arrhythmia in female RyR2R420Q CPVT patients . We generated here hiPSC-CM from two sisters of the same family, one exhibiting the mutation RyR2R420Q and the other without the mutation used as control. The experiments were conducted at 30-35 days after differentiation into cardiomyocytes. Using confocal microscopy, we assessed intracellular [Ca2+]i handling both spontaneous and during electrical pacing. To record [Ca2+]i transients, h-iPS-CMs were electrically field stimulated by two Pt electrodes at 1Hz. Spontaneous Ca2+ sparks and Ca2+ waves were recorded in quiescent cells, after [Ca2+]i transients recordings. For SR Ca2+ load quantification, h-iPS-CMs were rapidly perfused with 10 mmol/L caffeine. To induce β-adrenergic activation, 100nM isoproterenol (ISO) was added in some experiments. All confocal Ca2+ images analyses were performed by home-made routines using IDL software.
Results
First, we verify by immunofluorescence the expression of alpha-actinin in the differentiated h-iPS-CMs. Then, by confocal microscopy we found that woman CPVT h-iPS-CMs presented longer cycle length than wt h-iPS-CMs, correlating with the bradycardia observed in CPVT patients. The amplitude of the Ca2+ transients were significantly higher for CPVT h-iPS-CMs compared to wt; however, after ISO perfusion Ca2+ transients did not show a significant increase in CPVT h-iPS-CMs compared to CPVT h-iPS-CMs before ISO. SR Ca2+ load presented no differences between groups but the time decay constant of the caffeine-evoked Ca2+ transients were significantly faster in CPVT h-iPS-CMs whereas it became slower after ISO perfusion. In addition, analysis of Ca2+ pro-arrhythmogenic events were significantly augmented in CPVT h-iPS-CMs compared to wt h-iPS-CMs. After ISO perfusion, pro-arrhythmogenic events in CPVT cells presented no significant difference compared to CPVT cell before ISO perfusion. Although proarrhythmogenic events were similarly higher in both male and female hiPSC-CM, the Ca2+ handling characteristics were slightly different.
Conclusion
The RyR2R420Q mutation in woman CPVT h-iPS-CMs provides a reliable model to study CPVT in human context.
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Targeting Orai1-Mediated Store-Operated Ca 2+ Entry in Heart Failure. Front Cell Dev Biol 2020; 8:586109. [PMID: 33117812 PMCID: PMC7578222 DOI: 10.3389/fcell.2020.586109] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
The archetypal store-operated Ca2+ channels (SOCs), Orai1, which are stimulated by the endo/sarcoplasmic reticulum (ER/SR) Ca2+ sensor stromal interaction molecule 1 (STIM1) upon Ca2+ store depletion is traditionally viewed as instrumental for the function of non-excitable cells. In the recent years, expression and function of Orai1 have gained recognition in excitable cardiomyocytes, albeit controversial. Even if its cardiac physiological role in adult is still elusive and needs to be clarified, Orai1 contribution in cardiac diseases such as cardiac hypertrophy and heart failure (HF) is increasingly recognized. The present review surveys our current arising knowledge on the new role of Orai1 channels in the heart and debates on its participation to cardiac hypertrophy and HF.
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Abstract
BACKGROUND Orai1 is a critical ion channel subunit, best recognized as a mediator of store-operated Ca2+ entry (SOCE) in nonexcitable cells. SOCE has recently emerged as a key contributor of cardiac hypertrophy and heart failure but the relevance of Orai1 is still unclear. METHODS To test the role of these Orai1 channels in the cardiac pathophysiology, a transgenic mouse was generated with cardiomyocyte-specific expression of an ion pore-disruptive Orai1R91W mutant (C-dnO1). Synthetic chemistry and channel screening strategies were used to develop 4-(2,5-dimethoxyphenyl)-N-[(pyridin-4-yl)methyl]aniline (hereafter referred to as JPIII), a small-molecule Orai1 channel inhibitor suitable for in vivo delivery. RESULTS Adult mice subjected to transverse aortic constriction (TAC) developed cardiac hypertrophy and reduced ventricular function associated with increased Orai1 expression and Orai1-dependent SOCE (assessed by Mn2+ influx). C-dnO1 mice displayed normal cardiac electromechanical function and cellular excitation-contraction coupling despite reduced Orai1-dependent SOCE. Five weeks after TAC, C-dnO1 mice were protected from systolic dysfunction (assessed by preserved left ventricular fractional shortening and ejection fraction) even if increased cardiac mass and prohypertrophic markers induction were observed. This is correlated with a protection from TAC-induced cellular Ca2+ signaling alterations (increased SOCE, decreased [Ca2+]i transients amplitude and decay rate, lower SR Ca2+ load and depressed cellular contractility) and SERCA2a downregulation in ventricular cardiomyocytes from C-dnO1 mice, associated with blunted Pyk2 signaling. There was also less fibrosis in heart sections from C-dnO1 mice after TAC. Moreover, 3 weeks treatment with JPIII following 5 weeks of TAC confirmed the translational relevance of an Orai1 inhibition strategy during hypertrophic insult. CONCLUSIONS The findings suggest a key role of cardiac Orai1 channels and the potential for Orai1 channel inhibitors as inotropic therapies for maintaining contractility reserve after hypertrophic stress.
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P3510Cardiac function and Ca2+-cycling are different according to the level of cardiac-specific FKBP12.6 overexpression. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz745.0374] [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: 11/14/2022] Open
Abstract
Abstract
Cardiac ryanodine receptors (RyR2) have a key role in excitation-contraction coupling by releasing Ca2+ from sarcoplasmic reticulum (SR). In cardiomyocytes, two FK506 binding protein (FKBP) isoforms have been shown to bind and to stabilize RyR2 opening: FKBP12 and FKBP12.6, the later having a stronger affinity for RyR2 despite its lower abundance. Cardiac-specific FKBP12.6 overexpressing mice have fewer arrhythmias induced by β-adrenergic stimulation than wild type (WT) mice, suggesting an implication of FKBP12.6 in an antiarrhythmic mechanism. Heart failure (HF) syndrome has a high incidence of arrhythmias, which may be explained by a decrease of FKBP isoform expression.
The precise mechanism of the antiarrhythmic effect of FKBP12.6 overexpression remains unknown.
To gain insight into this mechanism, we developed 2 transgenic mouse lines with cardiac-specific moderate- (TG1) and high- (TG2) FKBP12.6 overexpression levels. We characterized cardiac function, [Ca2+]i cycling and its response to β-adrenergic stimulation in both mouse lines.
TG1 and TG2 mice developed mild and marked cardiac hypertrophy, respectively, associated with basal cardiac function increase in TG1 mice only. In stimulated cardiomyocytes, [Ca2+]i transient amplitude, measured by confocal microscopy, was higher in TG1 than in WT mice, without a significant difference in their SR Ca2+ content. The effect of β-adrenergic stimulation (50 nM isoproterenol) was attenuated in TG1 mice compared to WT mice, in association with the prevention of pro-arrhythmogenic Ca2+ release events, such as Ca2+ waves. In contrast, TG2 mice showed [Ca2+]i handling characteristics similar to HF, with slower [Ca2+]i transient relaxation. Interestingly, and contrary to HF, pro-arrhythmogenic Ca2+ release events were also reduced in TG2.
These results indicate that the level of FKBP12.6 overexpression has distinct effects on cardiac function and on Ca2+-cycling and its response to β-adrenergic stimulation.
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P2558PDE4 regulates cardiac pacemaker function. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.0886] [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: 11/14/2022] Open
Abstract
Abstract
Background
Numerous epidemiological and clinical studies have revealed a positive correlation between heart rate (HR) and cardiovascular morbimortality. The autonomic nervous system is the major extracardiac determinant of HR. During sympathetic stimulation, the activation of β-adrenergic receptors (βAR) induces an increase in cAMP levels, leading to positive chronotropic effect. Among the 5 cardiac cAMP-PDE families, PDE4 is critical for controlling excitation-contraction coupling (ECC) during βAR stimulation in atrial and ventricular cells. PDE4 may also be important for automaticity. 3 genes encode for PDE4s: pde4a, pde4b, pde4d. Their respective contribution to the regulation of pacemaker activity remains ill-defined.
Purpose
Define the role of PDE4 isoforms in the regulation of cardiac pacemaker activity
Methods
Total PDE activity was determined in mouse sinoatrial node (SAN) tissue as the cAMP-hydrolytic activity measured in the absence of PDE inhibitor and the fraction corresponding to PDE4 activity was assessed by including the PDE4 inhibitor Ro-20-1724. The in vitro pacemaker activity was assessed by measuring spontaneous Ca2+ transients in Fluo4-loaded-SAN tissue. Images were obtained using confocal microscopy.
Results
Ro-20-1724 increased beating rate of intact SAN and increased PKA-phosphorylation of key ECC actors (ryanodine receptor, phospholamban and contractile proteins). PDE4 activity was found to account for 60% of the total cAMP-PDE activity in SAN (n=3 independent experiments). PDE4A, PDE4B and PDE4D isoforms were found to be expressed in mouse SAN (n=5 independent experiments). In PDE4D-, but not in PDE4B-deficient mice, Ca2+ homeostasis was altered in control conditions (ctrl) and after βAR stimulation with isoprenaline (iso). Indeed, ablation of PDE4D induced decreased beating rate (ctrl: 1.00±0.08 s–1 vs 1.57±0.05 s–1; iso: 1.71±0.17 s–1 vs 2.39±0.08 s–1, p<0.0001) and increased Ca2+ spark frequency (ctrl: 15.9±5.2 sparks/s/100 μm vs 1.9±0.4 sparks/s/100 μm; iso: 22.9±7.1 sparks/s/100 μm vs 0.6±0.2 sparks/s/100 μm, p<0.0001) (Figure).
Calcium Homeostasis in SAN cells
Conclusion
PDE4 controls pacemaker function in mice and PDE4D ablation strongly perturbs normal SAN activity.
Acknowledgement/Funding
ANR, Fondation Lefoulon Delalande, CORDDIM
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1178Unsuspected role of the cardiac PKA type I in excitation-contraction coupling and in heart failure development. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.0020] [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
The cAMP-dependent protein kinase (PKA) consists of two regulatory (R) and two catalytic (C) subunits and comprises two subtypes, PKAI and PKAII, defined by the nature of their regulatory subunits, RIα and RIIα respectively. Whereas PKAII is thought to play a key role in β-adrenergic (β-AR) regulation of cardiac contractility, the function of PKAI is unclear. To address this question, we generated mice with cardiomyocyte-specific and conditional invalidation of the RIα subunit of PKA. Tamoxifen injection in 8 weeks-old mice resulted in a >70% decrease in RIα protein without modification of other PKA subunits, which was associated with ∼2-fold increased basal PKA activity in RIα-KO mice (p<0.05, N=6/group). This translated into enhanced cardiac contraction and relaxation, as observed in vivo by increased fractional shortening and E-wave velocity (p<0.05, N=10/group) and ex vivo by increased LV pressure and maximal rate of contraction and relaxation (p<0.05, N=9/group). L-type Ca2+ current density was increased in ventricular myocytes from RIα-KO, and β-AR stimulation was decreased by ∼50% (p<0.05, n=38 cells for WT, and, n=40 for RIα-KO). Consistently, Ca2+ transients amplitude and relaxation kinetics were increased, along with increased occurrence of Ca2+ sparks and waves (p<0.05, n=44 cells for WT, and, n=50 for RIα KO). Phosphorylation of Ca2+ channels (CaV1.2), PLB, RyR2 and cMyBP-C at PKA sites was increased >2-fold (p<0.05, N=6/group) in RIα KO without modification of total protein expression. With age, these mice developed a congestive heart failure (HF) phenotype with massive hypertrophy and fibrosis which eventually led to death in 50% of RIα-KO mice at 50 weeks (versus 0% in WT, p<0.01). These results reveal a previously unsuspected role of PKA type I in cardiac excitation-contraction coupling and HF.
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Safety and efficacy of inactivated varicella zoster virus vaccine in immunocompromised patients with malignancies: a two-arm, randomised, double-blind, phase 3 trial. THE LANCET. INFECTIOUS DISEASES 2019; 19:1001-1012. [DOI: 10.1016/s1473-3099(19)30310-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/02/2019] [Accepted: 05/03/2019] [Indexed: 12/25/2022]
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Gender-Dependent Alteration of Ca 2+ and TNFα Signaling in db/ db Mice, an Obesity-Linked Type 2 Diabetic Model. Front Physiol 2019; 10:40. [PMID: 30792662 PMCID: PMC6374335 DOI: 10.3389/fphys.2019.00040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/14/2019] [Indexed: 01/11/2023] Open
Abstract
Cardiovascular complications are the primary death cause in type 2 diabetes, where inflammation can play a role. We, and others, have previously shown that, in diabetic cardiomyopathy, cardiac dysfunction is associated with Ca2+ mishandling. It is possible that diabetic cardiomyopathy differently affects men and women, as the latter present higher risk to develop heart failure and a higher plasmatic level of the pro-inflammatory cytokine, tumor necrosis factor alpha (TNFα), than men. However, the gender-dependent regulation of Ca2+ signaling in diabetes and its relationship with TNFα signaling are still unclear. Here, we analyzed TNFα signaling pathway and its role in Ca2+ signaling dysfunction in male and female rodent models of type 2 diabetes linked to obesity (db/db mice) using confocal microscopy in freshly isolated cardiomyocytes. TNFα increased [Ca2+]i transient amplitude and accelerated its decay without affecting SR Ca2+ load or Ca2+ spark frequency in cells from control mice. All TNFα effects on Ca2+ handling were prevented by the inhibition of the ceramidase and the phospholipase A2 (PLA2). While the plasmatic level of TNFα was similar in male and female db/db mice, only male db/db hearts over-expressed both TNFα converting enzyme (TACE) and the protective TNFα receptors 2 (TNF-R2). TNFα receptor 1 (TNF-R1) expression, involved in negative inotropic response of TNFα, was unchanged in both male and female db/db mice compared to controls. We found that male db/db mice cardiomyocytes presented a decrease in [Ca2+]i transient amplitude associated to a drop of sarcoplasmic reticulum Ca2+ load, not seen in female db/db mice. Interestingly, sustained incubation with TNFα did not restored Ca2+ signaling alteration observed in male db/db mice but still induces an increase in Ca2+ spark frequency as seen in control littermates. In cardiomyocytes from female db/db mice, TNFα had no visible effects on Ca2+ handling. In conclusion, our study shows that the alteration of Ca2+ signaling and TNFα, seen in db/db mice, is gender specific presenting an increase in TNFα cardio-protective pathway in male mice.
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QSOX1, a novel actor of cardiac protection upon acute stress in mice. J Mol Cell Cardiol 2018; 119:75-86. [DOI: 10.1016/j.yjmcc.2018.04.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/07/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022]
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What would you do? The relationship between state abortion restrictions and expectations of unintended pregnancy resolution. Contraception 2018. [DOI: 10.1016/j.contraception.2018.03.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ca 2+ handling remodeling and STIM1L/Orai1/TRPC1/TRPC4 upregulation in monocrotaline-induced right ventricular hypertrophy. J Mol Cell Cardiol 2018; 118:208-224. [PMID: 29634917 DOI: 10.1016/j.yjmcc.2018.04.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 01/07/2023]
Abstract
BACKGROUND Right ventricular (RV) function is the most important prognostic factor for pulmonary arterial hypertension (PAH) patients. The progressive increase of pulmonary vascular resistance induces RV hypertrophy (RVH) and at term RV failure (RVF). However, the molecular mechanisms of RVH and RVF remain understudied. In this study, we gained insights into cytosolic Ca2+ signaling remodeling in ventricular cardiomyocytes during the pathogenesis of severe pulmonary hypertension (PH) induced in rats by monocrotaline (MCT) exposure, and we further identified molecular candidates responsible for this Ca2+ remodeling. METHODS AND RESULTS After PH induction, hypertrophied RV myocytes presented longer action potential duration, higher and faster [Ca2+]i transients and increased sarcoplasmic reticulum (SR) Ca2+ content, whereas no changes in these parameters were detected in left ventricular (LV) myocytes. These modifications were associated with increased P-Ser16-phospholamban pentamer expression without altering SERCA2a (Sarco/Endoplasmic Reticulum Ca2+-ATPase) pump abundance. Moreover, after PH induction, Ca2+ sparks frequency were higher in hypertrophied RV cells, while total RyR2 (Ryanodine Receptor) expression and phosphorylation were unaffected. Together with cellular hypertrophy, the T-tubules network was disorganized. Hypertrophied RV cardiomyocytes from MCT-exposed rats showed decreased expression of classical STIM1 (Stromal Interaction molecule) associated with increased expression of muscle-specific STIM1 Long isoform, glycosylated-Orai1 channel form, and TRPC1 and TRPC4 channels, which was correlated with an enhanced Ca2+-release-activated Ca2+ (CRAC)-like current. Pharmacological inhibition of TRPCs/Orai1 channels in hypertrophied RV cardiomyocytes normalized [Ca2+]i transients amplitude, the SR Ca2+ content and cell contractility to control levels. Finally, we showed that most of these changes did not appear in LV cardiomyocytes. CONCLUSIONS These new findings demonstrate RV-specific cellular Ca2+ cycling remodeling in PH rats with maladaptive RVH and that the STIM1L/Orai1/TRPC1/C4-dependent Ca2+ current participates in this Ca2+ remodeling in RVH secondary to PH.
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Abstract
BACKGROUND Twenty states currently require that women seeking abortion be counseled on possible psychological responses, with six states stressing negative responses. The majority of research finds that women whose unwanted pregnancies end in abortion do not subsequently have adverse mental health outcomes; scant research examines this relationship for young women. METHODS Four waves of data from the National Longitudinal Study of Adolescent Health were analyzed. Population-averaged lagged logistic and linear regression models were employed to test the relationship between pregnancy resolution outcome and subsequent depressive symptoms, adjusting for prior depressive symptoms, history of traumatic experiences, and sociodemographic covariates. Depressive symptoms were measured using a nine-item version of the Center for Epidemiologic Studies Depression scale. Analyses were conducted among two subsamples of women whose unwanted first pregnancies were resolved in either abortion or live birth: (1) 856 women with an unwanted first pregnancy between Waves 2 and 3; and (2) 438 women with an unwanted first pregnancy between Waves 3 and 4 (unweighted n's). RESULTS In unadjusted and adjusted linear and logistic regression analyses for both subsamples, there was no association between having an abortion after an unwanted first pregnancy and subsequent depressive symptoms. In fully adjusted models, the most recent measure of prior depressive symptoms was consistently associated with subsequent depressive symptoms. CONCLUSIONS In a nationally representative, longitudinal dataset, there was no evidence that young women who had abortions were at increased risk of subsequent depressive symptoms compared with those who give birth after an unwanted first pregnancy.
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Poster session 3Cell growth, differentiation and stem cells - Heart511The role of the endocannabinoid system in modelling muscular dystrophy cardiac disease with induced pluripotent stem cells.512An emerging role of T lymphocytes in cardiac regenerative processes in heart failure due to dilated cardiomyopathy513Canonical wnt signaling reverses the ‘aged/senescent’ human endogenous cardiac stem cell phenotype514Hippo signalling modulates survival of human induced pluripotent stem cell-derived cardiomyocytes515Biocompatibility of mesenchymal stem cells with a spider silk matrix and its potential use as scaffold for cardiac tissue regeneration516A snapshot of genome-wide transcription in human induced pluripotent stem cell-derived hepatocyte-like cells (iPSC-HLCs)517Can NOS/sGC/cGK1 pathway trigger the differentiation and maturation of mouse embryonic stem cells (ESCs)?518Introduction of external Ik1 to human-induced pluripotent stem cell-derived cardiomyocytes via Ik1-expressing HEK293519Cell therapy of the heart studied using adult myocardial slices in vitro520Enhancement of the paracrine potential of human adipose derived stem cells when cultured as spheroid bodies521Mechanosensitivity of cardiomyocyte progenitor cells: the strain response in 2D and 3D environments522The effect of the vascular-like network on the maturation of the human induced pluripotent stem cell derived cardiomyocytes.Transcriptional control and RNA species - Heart525Gene expression regulation in heart failure: from pathobiology to bioinformatics526Human transcriptome in idiopathic dilated cardiomyopathy - a novel high throughput screening527A high-throghput approach unveils putative miRNA-mediated mitochondria-targeted cardioprotective circuits activated by T3 in the post ischemia reperfusion setting528The effect of uraemia on the expression of miR-212/132 and the calcineurin pathway in the rat heartCytokines and cellular inflammation - Heart531Lack of growth differentiation factor 15 aggravates adverse cardiac remodeling upon pressure-overload in mice532Blocking heteromerization of platelet chemokines ccl5 and cxcl4 reduces inflammation and preserves heart function after myocardial infarction533Is there an association between low-dose aspirin use and clinical outcome in HFPEF? Implications of modulating monocyte function and inflammatory mediator release534N-terminal truncated intracellular matrix metalloproteinase-2 expression in diabetic heart.535Expression of CD39 and CD73 on peripheral T-cell subsets in calcific aortic stenosis536Mast cells in the atrial myocardium of patients with atrial fibrillation: a comparison with patients in sinus rhythm539Characteristics of the inflammatory response in patients with coronary artery disease and arterial hypertension540Pro-inflammatory cytokines as cardiovascular events predictors in rheumatoid arthritis and asymptomatic atherosclerosis541Characterization of FVB/N murinic bone marrow-derived macrophage polarization into M1 and M2 phenotypes542The biological expression and thoracic anterior pain syndromeSignal transduction - Heart545The association of heat shock protein 90 and TGFbeta receptor I is involved in collagen production during cardiac remodelling in aortic-banded mice546Loss of the inhibitory GalphaO protein in the rostral ventrolateral medulla of the brainstem leads to abnormalities in cardiovascular reflexes and altered ventricular excitablitiy547Selenoprotein P regulates pressure overload-induced cardiac remodeling548Study of adenylyl cyclase activity in erythrocyte membranes in patients with chronic heart failure549Direct thrombin inhibitors inhibit atrial myocardium hypertrophy in a rat model of heart failure and atrial remodeling550Tissue factor / FVIIa transactivates the IGF-1R by a Src-dependent phosphorylation of caveolin-1551Notch signaling is differently altered in endothelial and smooth muscle cells of ascending aortic aneurysm patients552Frizzled 5 expression is essential for endothelial proliferation and migration553Modulation of vascular function and ROS production by novel synthetic benzopyran analogues in diabetes mellitusExtracellular matrix and fibrosis - Heart556Cardiac fibroblasts as inflammatory supporter cells trigger cardiac inflammation in heart failure557A role for galectin-3 in calcific aortic valve stenosis558Omega-3 polyunsaturated fatty acids- can they decrease risk for ventricular fibrillation?559Serum levels of elastin derived peptides and circulating elastin-antielastin immune complexes in sera of patients with coronary artery disease560Endocardial fibroelastosis is secondary to hemodynamic alterations in the chick model of hypoplastic left heart syndrome561Dynamics of serum levels of matrix metalloproteinases in primary anterior STEMI patients564Deletion of the alpha-7 nicotinic acetylcholine receptor changes the vascular remodeling induced by transverse aortic constriction in mice.565Extracellular matrix remodelling in response to venous hypertension: proteomics of human varicose veinsIon channels, ion exchangers and cellular electrophysiology - Heart568Microtubule-associated protein RP/EB family member 1 modulates sodium channel trafficking and cardiac conduction569Investigation of electrophysiological abnormalities in a rabbit athlete's heart model570Upregulation of expression of multiple genes in the atrioventricular node of streptozotocin-induced diabetic rat571miR-1 as a regulator of sinoatrial rhythm in endurance training adaptation572Selective sodium-calcium exchanger inhibition reduces myocardial dysfunction associated with hypokalaemia and ventricular fibrillation573Effect of racemic and levo-methadone on action potential of human ventricular cardiomyocytes574Acute temperature effects on the chick embryonic heart functionVasculogenesis, angiogenesis and arteriogenesis577Clinical improvement and enhanced collateral vessel growth after monocyte transplantation in mice578The role of HIF-1 alpha, VEGF and obstructive sleep apnoea in the development of coronary collateral circulation579Initiating cardiac repair with a trans-coronary sinus catheter intervention in an ischemia/reperfusion porcine animal model580Early adaptation of pre-existing collaterals after acute arteriolar and venular microocclusion: an in vivo study in chick chorioallantoic membraneEndothelium583EDH-type responses to the activator of potassium KCa2.3 and KCa3.1 channels SKA-31 in the small mesenteric artery from spontaneously hypertensive rats584The peculiarities of endothelial dysfunction in patients with chronic renocardial syndrome585Endothelial dysfunction, atherosclerosis of the carotid arteries and level of leptin in patient with coronary heart disease in combination with hepatic steatosis depend from body mass index.586Role of non-coding RNAs in thoracic aortic aneurysm associated with bicuspid aortic valve587Cigarette smoke extract abrogates atheroprotective effects of high laminar flow on endothelial function588The prognostic value of anti-connective tissue antibodies in coronary heart disease and asymptomatic atherosclerosis589Novel potential properties of bioactive peptides from spanish dry-cured ham on the endothelium.Lipids592Intermediate density lipoprotein is associated with monocyte subset distribution in patients with stable atherosclerosis593The characteristics of dyslipidemia in rheumatoid arthritisAtherosclerosis596Macrophages differentiated in vitro are heterogeneous: morphological and functional profile in patients with coronary artery disease597Palmitoylethanolamide promotes anti-inflammatory phenotype of macrophages and attenuates plaque formation in ApoE-/- mice598Amiodarone versus esmolol in the perioperative period: an in vitro study of coronary artery bypass grafts599BMPRII signaling of fibrocytes, a mesenchymal progenitor cell population, is increased in STEMI and dyslipidemia600The characteristics of atherogenesis and systemic inflammation in rheumatoid arthritis601Role of adenosine-to-inosine RNA editing in human atherosclerosis602Presence of bacterial DNA in thrombus aspirates of patients with myocardial infarction603Novel E-selectin binding polymers reduce atherosclerotic lesions in ApoE(-/-) mice604Differential expression of the plasminogen receptor Plg-RKT in monocyte and macrophage subsets - possible functional consequences in atherogenesis605Apelin-13 treatment enhances the stability of atherosclerotic plaques606Mast cells are increased in the media of coronary lesions in patients with myocardial infarction and favor atherosclerotic plaque instability607Association of neutrophil to lymphocyte ratio with presence of isolated coronary artery ectasiaCalcium fluxes and excitation-contraction coupling610The coxsackie- and adenovirus receptor (CAR) regulates calcium homeostasis in the developing heart611HMW-AGEs application acutely reduces ICaL in adult cardiomyocytes612Measuring electrical conductibility of cardiac T-tubular systems613Postnatal development of cardiac excitation-contraction coupling in rats614Role of altered Ca2+ homeostasis during adverse cardiac remodeling after ischemia/reperfusion615Experimental study of sarcoplasmic reticulum dysfunction and energetic metabolism in failing myocardium associated with diabetes mellitusHibernation, stunning and preconditioning618Volatile anesthetic preconditioning attenuates ischemic-reperfusion injury in type II diabetic patients undergoing on-pump heart surgery619The effect of early and delayed phase of remote ischemic preconditioning on ischemia-reperfusion injury in the isolated hearts of healthy and diabetic rats620Post-conditioning with 1668-thioate leads to attenuation of the inflammatory response and remodeling with less fibrosis and better left ventricular function in a murine model of myocardial infarction621Maturation-related changes in response to ischemia-reperfusion injury and in effects of classical ischemic preconditioning and remote preconditioningMitochondria and energetics624Phase changes in myocardial mitochondrial respiration caused by hypoxic preconditioning or periodic hypoxic training625Desmin mutations depress mitochondrial metabolism626Methylene blue modulates mitochondrial function and monoamine oxidases-related ROS production in diabetic rat hearts627Doxorubicin modulates the real-time oxygen consumption rate of freshly isolated adult rat and human ventricular cardiomyocytesCardiomyopathies and fibrosis630Effects of genetic or pharmacologic inhibition of the ubiquitin/proteasome system on myocardial proteostasis and cardiac function631Suppression of Wnt signalling in a desmoglein-2 transgenic mouse model for arrhythmogenic cardiomyopathy632Cold-induced cardiac hypertrophy is reversed after thermo-neutral deacclimatization633CD45 is a sensitive marker to diagnose lymphocytic myocarditis in endomyocardial biopsies of living patients and in autopsies634Atrial epicardial adipose tissue derives from epicardial progenitors635Caloric restriction ameliorates cardiac function, sympathetic cardiac innervation and beta-adrenergic receptor signaling in an experimental model of post-ischemic heart failure636High fat diet improves cardiac remodelling and function after extensive myocardial infarction in mice637Epigenetic therapy reduces cardiac hypertrophy in murine models of heart failure638Imbalance of the VHL/HIF signaling in WT1+ Epicardial Progenitors results in coronary vascular defects, fibrosis and cardiac hypertrophy639Diastolic dysfunction is the first stage of the developing heart failure640Colchicine aggravates coxsackievirus B3 infection in miceArterial and pulmonary hypertension642Osteopontin as a marker of pulmonary hypertension in patients with coronary heart disease combined with chronic obstructive pulmonary disease643Myocardial dynamic stiffness is increased in experimental pulmonary hypertension partly due to incomplete relaxation644Hypotensive effect of quercetin is possibly mediated by down-regulation of immunotroteasome subunits in aorta of spontaneously hypertensive rats645Urocortin-2 improves right ventricular function and attenuates experimental pulmonary arterial hypertension646A preclinical evaluation of the anti-hypertensive properties of an aqueous extract of Agathosma (Buchu)Biomarkers648The adiponectin level in hypertensive females with rheumatoid arthritis and its relationship with subclinical atherosclerosis649Markers for identification of renal dysfunction in the patients with chronic heart failure650cardio-hepatic syndromes in chronic heart failure: North Africa profile651To study other biomarkers that assess during myocardial infarction652Interconnections of apelin levels with parameters of lipid metabolism in hypertension patients653Plasma proteomics in hypertension: prediction and follow-up of albuminuria during chronic renin-angiotensin system suppression654Soluble RAGE levels in plasma of patients with cerebrovascular events. Cardiovasc Res 2016. [DOI: 10.1093/cvr/cvw150] [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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DI-089 New approach to the management of the hereditary fructose intolerance hypoglycaemia: Treatment with oral mannose. Eur J Hosp Pharm 2016. [DOI: 10.1136/ejhpharm-2016-000875.355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Store Operated Calcium Channels, New Targets of Aldosterone in Cardiomyocytes. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.3264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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A sparse digital signal model for ultrasonic nondestructive evaluation of layered materials. ULTRASONICS 2015; 62:160-173. [PMID: 26092090 DOI: 10.1016/j.ultras.2015.05.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 12/02/2014] [Accepted: 05/19/2015] [Indexed: 06/04/2023]
Abstract
Signal modeling has been proven to be an useful tool to characterize damaged materials under ultrasonic nondestructive evaluation (NDE). In this paper, we introduce a novel digital signal model for ultrasonic NDE of multilayered materials. This model borrows concepts from lattice filter theory, and bridges them to the physics involved in the wave-material interactions. In particular, the proposed theoretical framework shows that any multilayered material can be characterized by a transfer function with sparse coefficients. The filter coefficients are linked to the physical properties of the material and are analytically obtained from them, whereas a sparse distribution naturally arises and does not rely on heuristic approaches. The developed model is first validated with experimental measurements obtained from multilayered media consisting of homogeneous solids. Then, the sparse structure of the obtained digital filter is exploited through a model-based inverse problem for damage identification in a carbon fiber-reinforced polymer (CFRP) plate.
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Epac contributes to cardiac hypertrophy and amyloidosis induced by radiotherapy but not fibrosis. Radiother Oncol 2014; 111:63-71. [PMID: 24721545 DOI: 10.1016/j.radonc.2014.01.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 01/06/2014] [Accepted: 01/28/2014] [Indexed: 01/22/2023]
Abstract
BACKGROUND Cardiac toxicity is a side-effect of anti-cancer treatment including radiotherapy and this translational study was initiated to characterize radiation-induced cardiac side effects in a population of breast cancer patients and in experimental models in order to identify novel therapeutic target. METHODS The size of the heart was evaluated in CO-HO-RT patients by measuring the Cardiac-Contact-Distance before and after radiotherapy (48months of follow-up). In parallel, fibrogenic signals were studied in a severe case of human radiation-induced pericarditis. Lastly, radiation-induced cardiac damage was studied in mice and in rat neonatal cardiac cardiomyocytes. RESULTS In patients, time dependent enhancement of the CCD was measured suggesting occurrence of cardiac hypertrophy. In the case of human radiation-induced pericarditis, we measured the activation of fibrogenic (CTGF, RhoA) and remodeling (MMP2) signals. In irradiated mice, we documented decreased contractile function, enlargement of the ventricular cavity and long-term modification of the time constant of decay of Ca(2+) transients. Both hypertrophy and amyloid deposition were correlated with the induction of Epac-1; whereas radiation-induced fibrosis correlated with Rho/CTGF activation. Transactivation studies support Epac contribution in hypertrophy stimulation and showed that radiotherapy and Epac displayed specific and synergistic signals. CONCLUSION Epac-1 has been identified as a novel regulator of radiation-induced hypertrophy and amyloidosis but not fibrosis in the heart.
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Complications of chemotherapy, a basic science update. Presse Med 2013; 42:e352-61. [PMID: 23972551 DOI: 10.1016/j.lpm.2013.06.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 06/12/2013] [Indexed: 11/25/2022] Open
Abstract
Anthracyclines, discovered 50 years ago, are antibiotics widely used as antineoplastic agents and are among the most successful anticancer therapies ever developed to treat a wide range of cancers, including hematological malignancies, soft tissue sarcomas and solid tumors. However, some anthracyclines, including doxorubicin, exhibit major signs of cardiotoxicity that may ultimately lead to heart failure (HF). Despite intensive research on doxorubicine-induced cardiotoxicity, the underlying mechanisms responsible for doxorubicin-induced cardiotoxicity have not been fully elucidated yet. Published literature so far has focused mostly on mitochondria dysfunction with consequent oxidative stress, Ca(2+) overload, and cardiomyocyte death as doxorubicin side effects, leading to heart dysfunction. This review focuses on the current understanding of the molecular mechanisms underlying doxorubicin-induced cardiomyocyte death (i.e.: cardiomyocyte death, mitochondria metabolism and bioenergetic alteration), but we will also point to new directions of possible mechanisms, suggesting potent prior or concomitant alterations of specific signaling pathways with molecular actors directly targeted by the anticancer drugs itself (i.e. calcium homeostasis or cAMP signaling cascade). The mechanisms of anticancer cardiac toxicity may be more complex than just mitochondria dysfunction. Partnership of both basic and clinical research is needed to promote new strategies in diagnosis, therapies with concomitant cardioprotection in order to achieve cancer treatment with acceptable cardiotoxicity along life span.
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Robust anti-arrhythmic efficacy of verapamil and flunarizine against dofetilide-induced TdP arrhythmias is based upon a shared and a different mode of action. Br J Pharmacol 2010; 161:162-75. [PMID: 20718748 DOI: 10.1111/j.1476-5381.2010.00883.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The high predisposition to Torsade de Pointes (TdP) in dogs with chronic AV-block (CAVB) is well documented. The anti-arrhythmic efficacy and mode of action of Ca(2+) channel antagonists, flunarizine and verapamil against TdP were investigated. EXPERIMENTAL APPROACH Mongrel dogs with CAVB were selected based on the inducibility of TdP with dofetilide. The effects of flunarizine and verapamil were assessed after TdP and in different experiments to prevent dofetilide-induced TdP. Electrocardiogram and ventricular monophasic action potentials were recorded. Electrophysiological parameters and short-term variability of repolarization (STV) were determined. In vitro, flunarizine and verapamil were added to determine their effect on (i) dofetilide-induced early after depolarizations (EADs) in canine ventricular myocytes (VM); (ii) diastolic Ca(2+) sparks in RyR2(R4496+/+) mouse myocytes; and (iii) peak and late I(Na) in SCN5A-HEK 293 cells. KEY RESULTS Dofetilide increased STV prior to TdP and in VM prior to EADs. Both flunarizine and verapamil completely suppressed TdP and reversed STV to baseline values. Complete prevention of TdP was achieved with both drugs, accompanied by the prevention of an increase in STV. Suppression of EADs was confirmed after flunarizine. Only flunarizine blocked late I(Na). Ca(2+) sparks were reduced with verapamil. CONCLUSIONS AND IMPLICATIONS Robust anti-arrhythmic efficacy was seen with both Ca(2+) channel antagonists. Their divergent electrophysiological actions may be related to different additional effects of the two drugs.
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Substance use among university students at the St Augustine campus of the University of the West Indies. W INDIAN MED J 2010; 59:641-649. [PMID: 21702236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE Substance use and abuse is a well known public health risk that peaks in persons between 18 and 25 years of age and is prevalent among university students. While this has been repeatedly documented in developed nations, there have been limited studies in the English-speaking Caribbean. This study therefore sought to assess the prevalence of alcohol, tobacco and marijuana use among university students in the English-speaking Caribbean and any associated risk factors. METHODS The study was designed as a descriptive, cross-sectional study to assess substance use in full-time, undergraduate students of The University of the West Indies (UWI), Trinidad and Tobago, over a six-month period. Questionnaires were distributed and students asked to self-report on their use of alcohol, tobacco and marijuana during the preceding six months. RESULTS The six-month prevalence rate for alcohol was 70% and 28% of students were identified as regular users. Binge drinking was estimated at 31%. Muslims were least likely to have used alcohol when compared to other religious groupings. The prevalence rate for tobacco and marijuana was 17% and 13%, respectively Ten per cent used all three substances. The use of all three substances was associated with multiple problems. CONCLUSION We conclude that substance use is common among many students of the UWI but generally lower than reports from other regions of the world. Despite this, substance use is associated with a number of problems and immediate educational interventions may be necessary to assist students in making informed and responsible choices.
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Functional characterization of the cAMP-binding proteins Epac in cardiac myocytes. Pharmacol Rep 2009; 61:146-53. [PMID: 19307703 DOI: 10.1016/s1734-1140(09)70017-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 01/15/2009] [Indexed: 11/29/2022]
Abstract
The cyclic AMP (cAMP)-binding proteins, Epac, are guanine nucleotide exchange factors for the Ras-like small GTPases. Since their discovery in 1998 and with the development of specific Epac agonists, many data in the literature have illustrated their critical role in multiple cellular events mediated by the second messenger cAMP. Given the importance of cAMP in cardiovascular physiology and physiopathology, there is a growing interest to delineate the role of these multi-domain Epac in the cardiovascular system. This review will focus on recent pharmacological and biochemical studies aiming at understanding the role of Epac in cardiomyocyte signaling and hypertrophy.
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The impact of steroids given with macrolide therapy on experimental Mycoplasma pneumoniae respiratory infection. J Infect Dis 2008; 198:1180-8. [PMID: 18717637 DOI: 10.1086/591915] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Systemic steroids have been advocated in addition to antimicrobial therapy for severe Mycoplasma pneumoniae pneumonia. We evaluated the efficacy of clarithromycin, dexamethasone, and combination therapy for M. pneumoniae respiratory infection. METHODS Mice infected with M. pneumoniae were treated with clarithromycin, dexamethasone, combined clarithromycin/dexamethasone, or placebo daily; mice were evaluated at baseline and after 1, 3, and 6 days of therapy. Outcome variables included M. pneumoniae culture, lung histopathologic score (HPS), and bronchoalveolar lavage cytokine, chemokine, and growth factor concentrations. RESULTS Clarithromycin monotherapy resulted in the greatest reductions in M. pneumoniae concentrations. After 3 days of treatment, combination therapy significantly reduced lung HPS compared with placebo, clarithromycin, and dexamethasone alone, whereas, after 6 days of therapy, clarithromycin alone and combination therapy significantly reduced lung HPS compared with placebo. Concentrations of interleukin (IL)-12 p40, RANTES, macrophage chemotactic protein-1, and cytokine-induced neutrophil chemoattractant were significantly lower in mice treated with clarithromycin alone and/or combination therapy compared with dexamethasone alone and/or placebo; combination therapy resulted in a significantly greater reduction than clarithromycin alone for IL-12 p40 and RANTES. CONCLUSIONS Although monotherapy with clarithromycin had the greatest effect on reducing concentrations of M. pneumoniae, combination therapy had the greatest effect on decreasing levels of cytokines and chemokines as well as pulmonary histologic inflammation.
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Treatment of carotid cavernous fistulas using covered stents: midterm results in seven patients. AJNR Am J Neuroradiol 2007; 28:1762-8. [PMID: 17885249 PMCID: PMC8134221 DOI: 10.3174/ajnr.a0636] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND PURPOSE Carotid cavernous fistulas (CCF) can be effectively treated by using different therapeutic alternatives such as detachable balloons and detachable coils, alone or in combination with N-butyl-2-cyanoacrylate (n-BCA) or Onyx. Stents have also been used in an attempt to improve preservation of the parent artery while still occluding the fistula. We present our experience using balloon-expandable covered stents to treat CCF, focusing on arterial wall reconstruction. To our knowledge, this is the first series with midterm follow-up between 3 months and 3.5 years. MATERIALS AND METHODS From the 46 CCF treated at our institution between November 1998 and September 2006, a total of 7 posttraumatic direct CCF were treated using polytetrafluoroethylene (PTFE)-covered stents between April 2003 and September 2006. Five were treated with covered stents alone. One patient with transection of the internal carotid artery (ICA) first underwent bare stent placement to provide support for the covered stent. One patient had to be treated with coils and n-BCA. RESULTS Control angiograms obtained in the 7 patients demonstrated occlusion of the fistula and preservation of the ICA in all cases. There was no mortality and no immediate postprocedural morbidity. There was 1 case of morbidity identified at 1-month follow-up with asymptomatic occlusion of the ICA; the other 6 patients had angiographic follow-up between 3 and 42 months (mean, 18.4 months), with persistent occlusion of the fistulas, patent stent grafts, and no significant intimal hyperplasia. CONCLUSIONS PTFE-covered stents are evolving as a promising intracranial therapeutic alternative to treat CCF and preserve the parent artery by reconstructing the arterial wall. They should be considered in patients in whom fistulas cannot be successfully occluded with detachable balloons or detachable coils. More investigation is required to further develop their specifications and indications.
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Respiratory tract infection with Mycoplasma pneumoniae in interleukin-12 knockout mice results in improved bacterial clearance and reduced pulmonary inflammation. Infect Immun 2006; 75:236-42. [PMID: 17074851 PMCID: PMC1828434 DOI: 10.1128/iai.01249-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycoplasma pneumoniae is a leading cause of pneumonia and is associated with asthma. Evidence links M. pneumoniae respiratory disease severity with interleukin-12 (IL-12) concentration in respiratory secretions. We evaluated the microbiologic, inflammatory, and pulmonary function indices of M. pneumoniae pneumonia in IL-12 (p35) knockout (KO) mice and wild-type (WT) mice to determine the role of IL-12 in M. pneumoniae respiratory disease. Eight-week-old wild-type BALB/c mice and 8-week-old IL-12 (p35) KO BALB/c mice were inoculated once intranasally with 10(7) CFU of M. pneumoniae. Mice were evaluated at days 2, 4, and 7 after inoculation. Outcome variables included quantitative bronchoalveolar lavage (BAL) M. pneumoniae culture, lung histopathologic scores (HPS), BAL cytokine concentrations determined by enzyme-linked immunosorbent assay (tumor necrosis factor alpha [TNF-alpha], gamma interferon [IFN-gamma], IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-10, and granulocyte-macrophage colony-stimulating factor) and plethysmography, before and after methacholine, to assess airway obstruction (AO) and airway hyperreactivity (AHR). IL-12 (p35) KO mice infected with M. pneumoniae were found to have significantly lower BAL M. pneumoniae concentrations compared with M. pneumoniae-infected WT mice. Lung HPS and the parenchymal pneumonia subscores (neutrophilic alveolar infiltrate), as well as AO, were significantly lower in infected KO mice. No difference was found for AHR. Infected KO mice had significantly lower BAL concentrations of IFN-gamma than WT mice; a trend toward lower BAL concentrations was observed for IL-10 (P = 0.065) and TNF-alpha (P = 0.078). No differences were found for IL-1beta, IL-2, IL-4, IL-5, or IL-6. The lack of IL-12 in experimental M. pneumoniae pneumonia was associated with less severe pulmonary disease and more rapid microbiologic and histologic resolution.
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Abstract
Endothelin-1 (ET-1), a powerful vasoconstrictor, is involved in vasospastic diseases such as coronary artery disease and subarachnoidal hemorrhage, as well as in renal and cardiovascular fibrotic remodeling. Transactivation of the epidermal growth factor receptor (EGFR) mediates ET-1 signaling in vascular smooth muscle cells (VSMCs) and isolated arteries. Moreover, EGFR is required for a full constrictive response to ET-1. However, the relevant mechanisms mediating EGFR transactivation in response to ET-1 have not been identified. The present study used isolated arteries and VSMCs to investigate the role of the EGFR ligand heparin binding-epidermal growth factor (HB-EGF) in ET-1-induced transactivation of EGFR, intracellular calcium mobilization, and VSMCs contraction. While baseline blood pressures were similar in HB-EGF-deficient and in wild-type littermate mice, the vasoconstrictor actions of ET-1 were attenuated in HB-EGF-/- animals. In isolated mouse carotid artery segments mounted in an arteriograph, ET-1 caused only a weak increase in isovolumetric tone in HB-EGF-deficient vessels, and this effect was mimicked by inhibition of EGFR tyrosine kinase or phosphoinositide 3-kinase (PI3K) in wild-type arteries with or without endothelium, indicating a specific role in VSMCs. EGFR or PI3K inhibitors had no effect on KCl-induced contraction, which was normal in HB-EGF-deficient mice. To confirm that the abnormal responses in HB-EGF-deficient mice were due to impaired EGFR signaling, we studied VSMCs from waved-2 (wa2) mice; these animals have a mutation causing a partial loss of function of EGFR tyrosine kinase activity. The ET-1-induced calcium peak was reduced by 30% in VSMCs from wa2 mice and from HB-EGF-/- mice. This effect was reproduced by preincubation of wild-type VSMCs with EGFR inhibitor AG1478 and PI3K inhibitors LY294002 and wortmannin. ProHB-EGF is bound to the cell membrane and released after cleavage by metalloproteinases; its action may contribute to effects of GPCR agonists on cell growth. Pretreatment of mouse VSMCs with batimastat, a metalloproteinase inhibitor, significantly attenuated ET-1-induced [Ca(2+)](i) response in wild-type cells. Human proHB-EGF has been shown to be the endogenous receptor for Corynebacterium diphteriae toxin (DT). Mutated DT toxin (CRM197) is devoid of toxicity but it neutralizes HB-EGF binding to EGFR. Pretreatment of human VSMCs from internal mammary arteries with CRM197 significantly blunted ET-1-stimulated calcium transients. In conclusion, these findings suggest that the mechanism of ET-1-induced vasoconstriction involves HB-EGF-mediated transactivation of the EGFR. This functional cascade requires modulation of agonist-induced calcium transient by EGFR and PI3K with extremely fast kinetics, suggesting a novel paradigm for GPCR-mediated calcium signaling, which may offer future therapeutic targets.
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New perspectives on the key role of calcium in the progression of heart disease. J Muscle Res Cell Motil 2003; 24:275-83. [PMID: 14620741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The heart continuously adapts to adjust its output to a continuum of pathophysiological situations ensuring adequate blood distribution. These situations range from high performance in well-trained athletes to failure in a variety of cardiac syndromes. Changes in the concentration of intracellular Ca2+ ([Ca2+]i) are crucial. They have immediate and late effects that can be oversimplified as follows. Immediate effects result from abrupt and large variations in [Ca2+]i triggering contraction after binding to the contractile proteins. These variations are involved in the process known to as excitation-contraction (EC) coupling. In contrast, the late effects involve a process that is, by analogy, referred to as excitation-transcription (ET) coupling. This process involves activation of gene expression by Ca2+. In this scheme, specific and localised elevations of Ca2+ can be converted into changes in gene expression with long-term effects on the adaptation of the heart to a sustained stimulus. There is emerging evidence of an extraordinary diversity of responses, depending on the location, intensity, and duration of Ca2+ signals that can be activated during pathology. Whereas alterations of cellular and molecular mechanisms underlying chronic pathology are relatively well defined, the initial changes and their hierarchy are unknown. However, the actual picture suggests promising perspectives for new therapeutic interventions on old targets or new strategies. Some of these aspects are reviewed here.
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A pilot C282Y hemochromatosis screening in Italian newborns by TaqMan technology. GENETIC TESTING 2001; 4:177-81. [PMID: 10953958 DOI: 10.1089/10906570050114894] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hereditary hemochromatosis (HH) is a disorder of iron metabolism that leads to iron overload in middle age and can be caused by homozygosity for the C282Y mutation in the HFE gene. Preliminary studies have estimated the frequency of this mutation at 0.5-1% in Italy, but this has not been verified on a large sample. We analyzed 1,331 Italian newborns for the C282Y mutation in the HFE gene using dried blood spots (DBS) from the Neonatal Screening Center in Turin, Italy. The mutation was assessed using a semi-automatable 5'-nuclease assay (TaqMan technology). We detected 55 heterozygotes and no homozygotes in our sampling, resulting in an overall frequency of 2.1% +/- 0.6 for the C282Y allele. Differences in allele frequency were observed, and ranged from 2.7% +/- 1.3 in samples from Northern Italy, to 1.7% +/- 0.9 in samples from Central-Southern Italy. The low frequency of the at-risk genotype for iron overload suggests that genetic screening for HFE in Italy would not be cost effective. The present study, in addition to defining C282Y frequency, documents detection of the major HFE mutation on routine DBS samples from neonatal screening programs using a semi-automatable, rapid, reliable, and relatively inexpensive approach.
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Suppression of voltage-gated L-type Ca2+ currents by polyunsaturated fatty acids in adult and neonatal rat ventricular myocytes. Proc Natl Acad Sci U S A 1997; 94:4182-7. [PMID: 9108126 PMCID: PMC20596 DOI: 10.1073/pnas.94.8.4182] [Citation(s) in RCA: 265] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/1997] [Indexed: 02/04/2023] Open
Abstract
Our recent data show that in cardiac myocytes polyunsaturated fatty acids (PUFAs) are antiarrhythmic. They reduce I(Na), shorten the action potential, shift the threshold for excitation to more positive potentials, and prolong the relative refractory period. In this study we use patch-clamp techniques in whole-cell mode and confocal Ca2+ imaging to examine the effects of PUFAs on the voltage-gated L-type Ca2+ current (I(Ca,L)), elementary sarcoplasmic reticulum Ca2+-release events (Ca2+-sparks), and [Ca2+]i transients in isolated rat ventricular myocytes. Extracellular application of eicosapentaenoic acid (EPA; C20:5 n - 3) produced a prompt and reversible concentration-dependent suppression of I(Ca,L). The concentration of EPA to produce 50% inhibition of I(Ca) was 0.8 microM in neonatal rat heart cells and 2.1 microM in adult ventricular myocytes. While the EPA induced suppression of I(Ca,L), it did not significantly alter the shape of the current-voltage relation but did produce a small, but significant, negative shift of the steady-state inactivation curve. The inhibition of I(Ca,L) was voltage- and time-dependent, but not use- or frequency-dependent. Other PUFAs, such as docosahexaenoic acid, arachidonic acid, linolenic acid, linoleic acid, conjugated linoleic acid, and eicosatetraynoic acid had similar effects on I(Ca,L) as EPA. All-trans-retinoic acid, which had been shown to suppress induced arrhythmogenic activity in rat heart cells, also produced a significant inhibition of I(Ca,L). The saturated stearic acid and the monounsaturated oleic acid had no effect on I(Ca,L). Because both I(Ca,L) and sarcoplasmic reticulum Ca2+-release underlie many cardiac arrhythmias, we examined the effects of EPA on I(Ca,L) and Ca2+-sparks. While EPA suppressed both, it did not change the temporal or spatial character of the Ca2+-sparks, nor did it alter the ability of I(Ca,L) to trigger Ca2+-sparks. We conclude that PUFAs may act as antiarrhythmic agents in vivo in normal and Ca2+-overloaded cells principally because they reduce Ca2+ entry by blocking I(Ca,L). Furthermore, PUFAs act directly to decrease I(Na) and I(Ca,L), but indirectly to reduce the [Ca2+]i transients and [Ca2+]i-activated membrane current. Although a negative inotropic action is associated with application of PUFAs, it is clear that by reducing I(Ca,L), I(Na) and Ca2+-sparks, PUFAs can reduce spontaneous extrasystoles in the heart. The mechanisms by which PUFAs act are discussed.
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Actin plays a role in both changes in cell shape and gene-expression associated with Schwann cell myelination. J Neurosci 1997; 17:241-50. [PMID: 8987752 PMCID: PMC6793673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Schwann cell (SC) differentiation into a myelinating cell requires concurrent interactions with basal lamina and an axon destined for myelination. As SCs differentiate, they undergo progressive morphological changes and initiate myelin-specific gene expression. We find that disrupting actin polymerization with cytochalasin D (CD) inhibits myelination of SC/neuron co-cultures. Basal lamina is present, neurons are healthy, and the inhibition is reversible. Electron microscopic analysis reveals that actin plays a role at two stages of SC differentiation. At 0.75-1.0 microg/ml CD, SCs do not differentiate and appear as "rounded" cells in contact with axons. This morphology is consistent with disruption of actin filaments and cell shape changes. However, at 0.25 microg/ml CD, SCs partially differentiate; they elongate and segregate axons but generally fail to form one-to-one relationships and spiral around the axon. In situ hybridizations reveal that SCs in CD-treated cultures do not express mRNAs encoding the myelin-specific proteins 2',3'-cyclic nucleotide phosphodiesterase (CNP), myelin-associated glycoprotein (MAG), and P0. Our results suggest that at the lower CD dose, SCs commence differentiation as evidenced by changes in cell shape but are unable to elaborate myelin lamellae because of a lack of myelin-specific mRNAs. We propose that F-actin influences myelin-specific gene expression in SCs.
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Inhibition of HIV-1-induced syncytia formation and infectivity by lipophosphoglycan from Leishmania. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1995; 10:496-505. [PMID: 8548328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In HIV-1 infection, the appearance of syncytia-inducing (SI) isolates is associated with a more rapid decline of CD4+ cells and progression to AIDS. Agents that inhibit either virus infection or syncytia formation have the potential to be therapeutically useful. Lipophosphoglycan (LPG), the major glycoconjugate of Leishmania, was recently shown to be a potent nonspecific inhibitor of viral membrane fusion. In this study, LPG demonstrated a dose-dependent inhibition of HIV-1-induced syncytia formation in CD4+ MT-2 cells infected with distinct SI isolates. Fragments of LPG were used to show that inhibition of syncytia formation was dependent on the length of the LPG fragment. Treatment of CD4+ cells or HIV-1 isolates with LPG inhibited infection in vitro. Furthermore, LPG inhibited the replication of SI viral isolates in CD4+ T cells in vitro. LPG had no toxic effects on peripheral blood mononuclear cells at the highest concentrations used in these assays. Further, LPG rapidly associated with the surface membrane of a human T cell line and subsequently disassociated over a 24-h period. The development of compounds capable of inhibiting HIV-induced syncytia formation should provide novel therapeutic approaches to control the spread of virus and disease progression.
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Cyclization Reactions of Tethered Radicals Derived From 4-O-Substituted α-D-erythro-Octa-2,6-dienopyranosides: Stereoselective Access to Carbocycles and Branched-Chain Sugars. Aust J Chem 1995. [DOI: 10.1071/ch9950333] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The chemo- and stereo- selectivities in the cyclization of tethered radicals, derived from α-D-erythro-octa-2,6-dienopyranosides, in which there is competition between 5-exo and 6-exo ring closures, have been examined. Use of silicon tethers resulted in a preferred 6-exo-trig addition. However, tethered mixed iodo acetals have shown an unprecedented relation between the stereogenic centre in the acetal and the preferred addition pathway. In addition, changes in the oxidation state at the termini of the olefins have a profound effect upon site selectivity, thus leading to 3-deoxy 3-C-substituted carbohydrates, off-template branched-chain sugars, or functionalized cyclopentanes.
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Early detection of HIV-1 in men from Kenya using a synthetic peptide and a p24 antigen enzyme-linked immunosorbent assay. AIDS 1994; 8:1625-6. [PMID: 7848603 DOI: 10.1097/00002030-199411000-00019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Heterogeneity of the early outward current in ventricular cells isolated from normal and hypertrophied rat hearts. J Physiol 1993; 469:111-38. [PMID: 7505822 PMCID: PMC1143864 DOI: 10.1113/jphysiol.1993.sp019807] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
1. The nature, magnitude and kinetics of the 4-aminopyridine-sensitive early outward current (Ito) were analysed in isolated ventricular myocytes from the septum, the apex and the left ventricular free wall of rat ventricles using the whole-cell voltage clamp method. The modulatory effect of pressure overload-induced cardiac hypertrophy on the regional variations of Ito was assessed in each topographical class of cells. 2. Voltage clamp experiments were performed at room temperature (20-25 degrees C) in the absence of Na+ on both sides of the membrane and in the presence of 3 mM CoCl2. Ito was studied from a holding potential of -80 mV and determined by subtraction of total outward currents elicited by the same protocols in the presence of 3 mM 4-aminopyridine (4-AP) from those obtained in its absence. 3. In normal hearts, membrane passive properties were very similar in each topographical class of cells. Our results confirmed that the predominant early outward current in rat ventricular cells was 4-AP-sensitive, time and voltage dependent, and demonstrated that the magnitude of the current varied on a regional basis: current density of Ito in left ventricular free wall cells (30.1 +/- 9.2 pA/pF at +60 mV) was larger than in apex cells (20.2 +/- 1.7 pA/pF) or in septum cells (11.9 +/- 3.3 pA/pF). We noticed a larger variability in data from left ventricular free wall compared with other regions. 4. No shift in steady-state voltage dependence of Ito activation and inactivation was found. However, the maximal computed chord conductances were (in microS/pF): 0.18 +/- 0.07 for left ventricular free wall cells, 0.13 +/- 0.02 for apex cells, and 0.08 +/- 0.02 for septum cells. These findings might reflect a differential distribution in functional channel densities. 5. No difference in voltage-dependent Ito activation kinetics was present with respect to topography. However, inactivation time constants in septum were longer than those of both other groups. 6. Left ventricular hypertrophy was induced by abdominal aortic constriction and its effects compared to the findings from normal rats. Hypertrophied cells had similar resting potentials but higher capacitance values than normal cells. Although Ito magnitude appeared not to be modified, the current density-voltage curves were slightly shifted to more positive potentials and significantly decreased as compared to normal cells (in pA/pF, at +60 mV): 8.4 +/- 5.0 in the left free wall group, 11.6 +/- 2.0 in the apex group, and 3.8 +/- 1.5 in the septum group.(ABSTRACT TRUNCATED AT 400 WORDS)
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An 80-kilodalton antigen from Histoplasma capsulatum that has homology to heat shock protein 70 induces cell-mediated immune responses and protection in mice. Infect Immun 1992; 60:2565-71. [PMID: 1612726 PMCID: PMC257204 DOI: 10.1128/iai.60.7.2565-2571.1992] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An extract of the cell wall and cell membrane from Histoplasma capsulatum yeast cells was assayed by Western blot (immunoblot) for reactivity with two monoclonal antibodies to heat shock protein 70. Four bands with molecular masses of 80, 66, 54, and 32 kDa bound both antibodies. The 80-kDa protein was isolated, analyzed for homology to heat shock protein 70, and tested for antigenicity and immunogenicity in C57BL/6 mice. The 80-kDa protein reacted with monoclonal antibody to heat shock protein 70. Sera from mice immunized with the antigen recognized H. capsulatum heat shock protein 70. Moreover, the amino-terminal sequence of the 80-kDa protein revealed substantial homology with heat shock protein 70 from several species. The 80-kDa protein induced delayed-type hypersensitivity responses in mice immunized with either viable yeast cells or antigen. Splenocytes from mice immunized with yeast cells or with antigen responded in vitro to the 80-kDa antigen. Immunization of mice with the antigen enhanced host resistance against a sublethal inoculum of H. capsulatum yeast cells, but it did not reduce the mortality of mice given a lethal challenge of yeast cells. Thus, this antigen manifests homology with members of the heat shock protein 70 family. Furthermore, the 80-kDa protein elicits cellular immune responses to H. capsulatum, and it mediates protective immunity.
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Simplified technique for subarachnoid anesthesia. REGIONAL ANESTHESIA 1992; 17:116. [PMID: 1581256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Protective efficacy of a 62-kilodalton antigen, HIS-62, from the cell wall and cell membrane of Histoplasma capsulatum yeast cells. Infect Immun 1991; 59:4459-64. [PMID: 1937804 PMCID: PMC259063 DOI: 10.1128/iai.59.12.4459-4464.1991] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We reported previously that a detergent extract of the cell wall and cell membrane of Histoplasma capsulatum yeast cells contains antigens recognized by T cells. In T-cell immunoblot analysis, a region encompassing 62 kDa was stimulatory for an H. capsulatum-reactive T-cell line and T-cell clones derived from C57BL/6 mice. In this study, we isolated a 62-kDa band, termed HIS-62, from electrophoresed cell wall and cell membrane of H. capsulatum yeast cells and examined its antigenicity and immunogenicity. C57BL/6, BALB/c, and CBA/J mice that were immunized with viable H. capsulatum yeast cells mounted a delayed-type hypersensitivity response to HIS-62 that was stronger than that of normal controls. Spleen cells from each strain of mouse immunized with viable yeast cells proliferated vigorously in response to HIS-62; conversely, splenocytes from control animals did not recognize this antigen. A T-cell line and 5 of 5 T-cell clones from C57BL/6 mice, 10 of 15 BALB/c T-cell hybridomas, and 8 of 12 CBA/J T-cell hybridomas recognized HIS-62. A cutaneous delayed-type hypersensitivity response to the antigen was apparent in each strain of mouse that was injected with 80 micrograms of HIS-62 mixed with Freund adjuvant. In addition, spleen cells from HIS-62-immunized mice proliferated in vitro in response to this antigen. Vaccination of each strain of mouse with 80 micrograms of HIS-62 conferred protection against a lethal intravenous challenge with H. capsulatum yeast cells. Thus, HIS-62 appears to be an important target of the cellular immune response to H. capsulatum and induces a protective immune response in mice.
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Inhibition of the pituitary-gonadal axis by a single intramuscular administration of D-Trp-6-LH-RH (decapeptyl) in a sustained-release formulation in patients with prostatic carcinoma. Prostate 1989; 14:291-300. [PMID: 2526325 DOI: 10.1002/pros.2990140402] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
For the past 6 years we used daily injection of luteinizing hormone-releasing hormone (LH-RH) agonists to treat patients with advanced prostate carcinoma. In this study we determined the hormonal response of the pituitary-testicular axis over a 2-month period and evaluated the safety and tolerance of the single intramuscular administration of sustained-release formulations of D-Trp-6-LH-RH microcapsules designed to release 50, 100, or 200 micrograms/day for over 1 month. Serum levels of LH, testosterone, and D-Trp-6-LH-RH were measured by RIA for up to 60 days in 10 patients with advanced prostatic carcinoma who had not received any previous drug therapy. After the administration of the microcapsules there was a biphasic increase in D-Trp-6-LH-RH serum levels. The maximal peak was obtained between 1 and 3 hr, and a second peak occurred between weeks 4 and 6. LH levels increased initially, with a maximal peak at 60 min, and elevated serum LH values persisted for more than 24 hr. LH levels began to fall on the second day, reaching subnormal values after 1 week. Serum testosterone rose during the first week and fell subsequently to less than 100 ng/dl. A rebound in LH and testosterone was seen about the 50th day after the microcapsule administration. Following the first week of therapy, we observed in all patients a significant decrease in bone pain, improvement in urinary flow obstruction, and a reversal of the signs of prostatism. No side effects were observed, and acceptance of the microcapsules was very good. Our results show that a single dose of D-Trp-6-LH-RH microcapsules suppresses of the pituitary-testicular axis for at least 50 days. D-Trp-6-LH-RH microcapsules facilitate the treatment and should lead to an improvement in the therapeutic response.
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Allelic variants of acetylcholinesterase: genetic evidence that all acetylcholinesterase forms in avian nerves and muscles are encoded by a single gene. Proc Natl Acad Sci U S A 1988; 85:7805-9. [PMID: 3174665 PMCID: PMC282282 DOI: 10.1073/pnas.85.20.7805] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Two acetylcholinesterase (AcChoEase) polypeptide chains, alpha and beta, are expressed in avian nerves and muscles with apparent molecular masses of 110 and 100 kDa, respectively. We now show that individual quails express alpha, beta, or both AcChoEase polypeptide chains. By mating studies we show that the two AcChoEase polypeptides are autosomal and segregate as codominant alleles in classical Mendelian fashion. Biochemical studies of the two allelic AcChoEase polypeptides indicate that they have the same turnover number, have the same Km for acetylcholine, are immunoprecipitated to the same extent with a monoclonal anti-AcChoEase antibody, and can assemble with equal efficiency into multimeric forms. Thus there are no obvious functional differences between the two alleles. In heterozygotes, the rates of synthesis of the two polypeptides are identical, suggesting that there are no differences in expression of these two genes. Within an individual, nerves and muscles always express the same AcChoEase forms isolated from muscle indicates that all AcChoEase forms are comprised of the same allelic polypeptide chains. In contrast to the nicotinic acetylcholine receptors that appear to be encoded by complex multigene families, our studies on AcChoEase show that all forms of this important synaptic component in electrically excitable cells are encoded by a single gene. Thus differences in assembly and localization of the multiple synaptic forms of AcChoEase must arise through posttranscriptional events, posttranslational modifications of a similar AcChoEase polypeptide chain or both.
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Tooth scaling and evolutionary dwarfism: an investigation of allometry in human pygmies. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1988; 77:117-32. [PMID: 3189517 DOI: 10.1002/ajpa.1330770117] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Gould has predicted that in rapidly dwarfed lineages the postcanine teeth exhibit a different scaling pattern than is the normal interspecific trend. His prediction of strong negative allometry has not been frequently tested in quantitative detail. Here we present results of scaling analyses of the molar teeth in African pygmies compared with other Africans of larger size and in Philippine pygmies compared with Filipinos of larger size. We find a pattern of strong negative allometry of tooth size to skull and body size in both these comparisons. This scaling pattern is explained by recourse to the developmental bases (known or inferred) of dwarfing in these populations. Body size decrease is related to low levels of the growth control substance insulin-like growth factor I (IGF-I), which does not appear to affect the size of the dentition. The implications of such developmental information for our understanding of allometric patterns in general, and dwarfing events in particular, are discussed.
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Detection of histoplasmal antigens in mice undergoing experimental pulmonary histoplasmosis. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1985; 132:752-6. [PMID: 4051311 DOI: 10.1164/arrd.1985.132.4.752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A micro-ELISA assay was developed for the quantitation of Histoplasma capsulatum antigen in lungs, bronchoalveolar lavage fluid (BALF), and serum of intranasally infected mice. As little as 0.2 ng of antigen/ml could be detected. During the course of experimental histoplasmosis, immunologically intact, thymus-containing mice (nu/+) had detectable histoplasmal antigens in their lungs, serum, and BALF within 1 day of challenge. Lung, BALF, and serum antigen concentration rose to a peak 2 wk after challenge; in nu/+ mice, antigen concentration then declined through the next 2 wk. In contrast, athymic nude mice have depressed cell-mediated immunity; their antigen concentration continued to rise throughout the course of progressive, ultimately lethal, illness. Antigen concentrations correlated with quantitative cultures of the lungs and BALF. There was little cross reactivity in mice challenged intranasally with Candida albicans or Blastomyces dermatitidis. The sensitivity of this test, and the apparently minimal cross reactivity, suggest that the micro-ELISA for histoplasmal antigen might have significant clinical application in diagnosing and monitoring the course of histoplasmosis.
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Murine model of paracoccidioidomycosis. Production of fatal acute pulmonary or chronic pulmonary and disseminated disease: immunological and pathological observations. JOURNAL OF EXPERIMENTAL PATHOLOGY 1984; 1:241-255. [PMID: 6599939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A model of fatal acute pulmonary or chronic pulmonary and disseminated paracoccidioidomycosis was developed by intranasal challenge of young (3-4-week-old) mice with high doses (2.5-10 X 10(7) units) or low doses (0.1-1 X 10(7)) of yeast-phase Paracoccidioides brasiliensis. Fatal acute paracoccidioidomycosis was dose dependent; 10, 5, and 2.5 X 10(7) viable units of P. brasiliensis produced 100%, 66%, and 17% mortality, respectively, within 11 days. The pathologic picture was that of consolidation with a neutrophil infiltrate. Infection of adult (7-8-week-old) mice with even 10 X 10(7) units did not produce acute fatal paracoccidioidomycosis. The model of fatal acute paracoccidioidomycosis lends itself well to studies of therapeutic intervention. Increasing degrees of chronic pulmonary-disseminated paracoccidioidomycosis were produced by pulmonary infection of young mice with 0.1-1 X 10(7) viable units of P. brasiliensis. Although mice in all groups appeared healthy, pathology in lungs, liver, and spleen was evident at 7 and 10 weeks postinfection. Histopathologic observation revealed acinonodular granulomatous inflammation. At 12 weeks postinfection, there was evidence of less pathology, and of clearing of abscesses. In contrast to the pathology produced by 0.1 X 10(7) P. brasiliensis in young mice, no pathology evident on gross examination was produced by a similar dose in adult mice. Immunological evaluations of mice with chronic pulmonary-disseminated disease showed that spleen cells, but not lymph node cells, had significantly depressed blastogenic responses to concanavalin A (ConA) early after infection. However, at 12 weeks postinfection, when pathological examination indicated beginning resolution of infection, spleen cell responses to ConA were normal. The model of chronic disease is of interest for further immunological studies as well.
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[Significance of lymphocytotoxic antibodies in kidney transplantation revisited (author's transl)]. LA NOUVELLE PRESSE MEDICALE 1981; 10:303-7. [PMID: 7015277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Lymphocytotoxic antibodies against peripheral blood lymphocytes (LT anti-PBL) were investigated in sera obtained before and after 148 kidney transplantations. Reactivity was assayed on a panel of unrelated donor cells and, in 15 cases, on the kidney donor's lymphocytes. Pretransplant LT anti-PBL, whether they persisted or not after grafting, were of no prognostic value. However, they were associated with longer periods of treatment by chronic hemodialysis, due to an increased frequency of positive cross-matches against potential donors. De novo occurrence of LT anti-PBL after transplantation was more frequently observed in mismatched kidney recipients, and they were significantly correlated to graft failure. In this respect, LT specifically directed to the kidney donor are of more avail than those directed to the panel. Anti-B lymphocyte LT do not seem to be more specific or more predictive for the follow-up of these patients.
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