The Notch pathway controls fibrotic and regenerative repair in the adult heart

Aims In the adult heart, Notch signalling regulates the response to injury. Notch inhibition leads to increased cardiomyocyte apoptosis, and exacerbates the development of cardiac hypertrophy and fibrosis. The role of Notch in the mesenchymal stromal cell fraction, which contains cardiac fibroblasts and cardiac precursor cells, is, however, largely unknown. In the present study, we evaluate, therefore, whether forced activation of the Notch pathway in mesenchymal stromal cells regulates pathological cardiac remodelling. Methods and results We generated transgenic mice overexpressing the Notch ligand Jagged1 on the surface of cardiomyocytes to activate Notch signalling in adjacent myocyte and non-myocyte cells. In neonatal transgenic mice, activated Notch sustained cardiac precursor and myocyte proliferation after birth, and led to increased numbers of cardiac myocytes in adult mice. In the adult heart under pressure overload, Notch inhibited the development of cardiomyocyte hypertrophy and transforming growth factor-β/connective tissue growth factor-mediated cardiac fibrosis. Most importantly, Notch activation in the stressed adult heart reduced the proliferation of myofibroblasts and stimulated the expansion of stem cell antigen-1-positive cells, and in particular of Nkx2.5-positive cardiac precursor cells. Conclusions We conclude that Notch is pivotal in the healing process of the injured heart. Specifically, Notch regulates key cellular mechanisms in the mesenchymal stromal cell population, and thereby controls the balance between fibrotic and regenerative repair in the adult heart. Altogether, these findings indicate that Notch represents a unique therapeutic target for inducing regeneration in the adult heart via mobilization of cardiac precursor cell

Développement d'une échelle interdisciplinaire bilingue évaluant l'auto-efficacité à participer à l'aide médicale à mourir

Medical Assistance in Dying (MAiD) is a complex process involving the person seeking care and their relatives. MAiD involves physical, psychosocial and spiritual needs, and consequently the involvement of an interdisciplinary team is beneficial. Therefore, updating the knowledge and skills of healthcare and social services professionals is critical. An interdisciplinary team from Laval University (Quebec, Canada) has developed a continuous training program for all health care and social services professionals who could be involved in the care of persons who request MAiD and their loved ones. It is crucial to assess whether the objectives of the continuous training program are being met, especially since this new training addresses several complex issues (legal, ethical, and clinical). Bandura's self-efficacy theory has been widely used to develop scales for assessing the impact of training programs and identifying knowledge gaps. Bandura's theory states that feeling secure in one's self-efficacy leads to self-determined motivation. Although there are various scales intended to measure self-efficacy in palliative care, none include self-efficacy for participating in the process surrounding MAiD. As a result, we aim to create a bilingual (English-French) interdisciplinary scale to assess self-efficacy for participating in the process surrounding MAiD. The scale will allow decision-makers and researchers to identify current knowledge gaps. It will also be useful for assessing the impact of current and future training programs addressing this end-of-life practice. In this work in progress, we briefly introduce the training program and the future steps in the development and validation of the scale.L'aide médicale à mourir (AMM) est un processus complexe impliquant la personne qui demande le soin et ses proches. L'AMM implique des besoins physiques, psychosociaux et spirituels. Par conséquent, l'implication d'une équipe interdisciplinaire est bénéfique et la mise à niveau des connaissances et des compétences des professionnel.es est essentielle. Une équipe interdisciplinaire de l'Université Laval (Québec, Canada) a développé un programme de formation continue destiné aux professionnelles de la santé et des services sociaux susceptible d'être impliqué es dans ls soins et services des personnes qui demandent l’AMM et de leurs proches. Il est crucial d'évaluer si les objectifs du programme de formation continue sont atteints, d'autant plus que cette nouvelle formation aborde plusieurs questions complexes (juridiques, éthiques et cliniques). La théorie du sentiment d'auto efficacité de Bandura a été largement utilisée pour développer des échelles permettant d'évaluer l'impact des programmes de formation et d'identifier les lacunes en matière de connaissances. Cette théorie stipule que le fait de se sentir sûre de son efficacité personnelle conduit à une motivation intrinsèque à accomplir le comportement visé. Bien qu'il existe plusieurs échelles destinées à mesurer l'auto-efficacité dans le domaine des soins palliatifs, aucune n'inclut l'auto-efficacité pour la participation au processus entourant l’AMM. Par conséquent, nous développons une échelle interdisciplinaire bilingue (anglais-français) pour évaluer l'auto-efficacité à participer au processus entourant l’AMM. L'échelle permettra aux décideuses, décideurs et aux chercheuses et chercheurs d'identifier les lacunes actuelles en matière de connaissances. Elle sera également utile pour évaluer l'impact des programmes de formation actuels et futurs portant sur cette pratique de fin de vie. Dans cet article, nous présentons brièvement le programme de formation et les étapes futures du développement et de la validation de l'échelle

A transposable element into the human long noncoding RNA CARMEN is a switch for cardiac precursor cell specification.

AIMS The major cardiac cell types composing the adult heart arise from common multipotent precursor cells. Cardiac lineage decisions are guided by extrinsic and cell-autonomous factors, including recently discovered long noncoding RNAs (lncRNAs). The human lncRNA CARMEN, which is known to dictate specification towards the cardiomyocyte (CM) and the smooth muscle cell (SMC) fates, generates a diversity of alternatively spliced isoforms. METHODS AND RESULTS The CARMEN locus can be manipulated to direct human primary cardiac precursor cells (CPCs) into specific cardiovascular fates. Investigating CARMEN isoform usage in differentiating CPCs represents therefore a unique opportunity to uncover isoform-specific function in lncRNAs. Here, we identify one CARMEN isoform, CARMEN-201, to be crucial for SMC commitment. CARMEN-201 activity is encoded within an alternatively-spliced exon containing a MIRc short interspersed nuclear element. This element binds the transcriptional repressor REST (RE1 Silencing Transcription Factor), targets it to cardiogenic loci, including ISL1, IRX1, IRX5, and SFRP1, and thereby blocks the CM gene program. In turn, genes regulating SMC differentiation are induced. CONCLUSIONS These data show how a critical physiological switch is wired by alternative splicing and functional transposable elements in a long noncoding RNA. They further demonstrated the crucial importance of the lncRNA isoform CARMEN-201 in SMC specification during heart development

Assessment of bleeding risk in cancer patients treated with anticoagulants for venous thromboembolic events

IntroductionAnticoagulant is the cornerstone of the management of VTE at the cost of a non-negligible risk of bleeding. Reliable and validated clinical tools to predict thromboembolic and hemorrhagic events are crucial for individualized decision-making for the type and duration of anticoagulant treatment. We evaluate the available risk models in real life cancer patients with VTE. The objectives of the study were to describe the bleeding of cancer patients with VTE and to evaluate the performance of the different bleeding models to predict the risk of bleeding during a 6-month follow-up.Materials and MethodsVTE-diagnosed patient's demographic and clinical characteristics, treatment regimens and outcomes for up to 6 months were collected. The primary endpoint was the occurrence of a major bleeding (MB) or a clinically relevant non major bleeding (CRNMB) event, categorized according to the ISTH criteria.ResultsDuring the 6-months follow-up period, 26 out of 110 included patients (26.7%) experienced a bleeding event, with 3 recurrences of bleeding. Out of the 29 bleeding events, 19 events were CRNMB and 10 MB. One patient died because of a MB. Bleeding occurred in 27 % of the patients treated with DOACs and 22% of the patients treated with LMWH. Most of the bleedings were gastrointestinal (9 events, 31%); 26.9% of the bleedings occurred in patient with colorectal cancer and 19.6% in patients with lung cancer. In our cohort, none of the 10 RAMs used in our study were able to distinguish cancer patients with a low risk of bleeding, from all bleeding or non-bleeding patients. The Nieto et al. RAM had the best overall performance (C-statistic = 0.730, 95% CI (0.619–0.840)). However, it classified 1 out of 5 patients with major bleeding in the low risk of bleeding group. The rest of the RAMs showed a suboptimal result, with a range of C-statistic between 0.489, 95%CI (0.360–0.617)) and 0.532, 95%CI (0.406–0.658)).ConclusionsThe management of CAT patients is challenging due to a higher risk of both recurrent VTE and bleeding events, as compared with non-cancer patients with VTE. None of the existing RAMs was able to consistently identify patients with risk of anticoagulant associated bleeding events

The long noncoding RNA Wisper controls cardiac fibrosis and remodeling

Long noncoding RNAs (lncRNAs) are emerging as powerful regulators of cardiac development and disease. However, our understanding of the importance of these molecules in cardiac fibrosis is limited. Using an integrated genomic screen, we identified Wisper (Wisp2 super-enhancer–associated RNA) as a cardiac fibroblast–enriched lncRNA that regulates cardiac fibrosis after injury. Wisper expression was correlated with cardiac fibrosis both in a murine model of myocardial infarction (MI) and in heart tissue from human patients suffering from aortic stenosis. Loss-of-function approaches in vitro using modified antisense oligonucleotides (ASOs) demonstrated that Wisper is a specific regulator of cardiac fibroblast proliferation, migration, and survival. Accordingly, ASO-mediated silencing of Wisper in vivo attenuated MI-induced fibrosis and cardiac dysfunction. Functionally, Wisper regulates cardiac fibroblast gene expression programs critical for cell identity, extracellular matrix deposition, proliferation, and survival. In addition, its association with TIA1-related protein allows it to control the expression of a profibrotic form of lysyl hydroxylase 2, implicated in collagen cross-linking and stabilization of the matrix. Together, our findings identify Wisper as a cardiac fibroblast–enriched super-enhancer–associated lncRNA that represents an attractive therapeutic target to reduce the pathological development of cardiac fibrosis in response to MI and prevent adverse remodeling in the damaged heart

Cardiomyocyte Lineage Specification in Adult Human Cardiac Precursor Cells Via Modulation of Enhancer-Associated Long Noncoding RNA Expression

SummaryThe mechanisms controlling differentiation in adult cardiac precursor cells (CPCs) are still largely unknown. In this study, CPCs isolated from the human heart were found to produce predominantly smooth muscle cells but could be redirected to the cardiomyocyte fate by transient activation followed by inhibition of NOTCH signaling. NOTCH inhibition repressed MIR-143/145 expression, and blocked smooth muscle differentiation. Expression of the microRNAs is under control of CARMEN, a long noncoding RNA associated with an enhancer located in the MIR-143/145 locus and target of NOTCH signaling. The CARMEN/MIR-145/143 axis represents, therefore, a promising target to favor production of cardiomyocytes in cell replacement therapies

ALDH1A3 Is the Key Isoform That Contributes to Aldehyde Dehydrogenase Activity and Affects <i>in Vitro</i> Proliferation in Cardiac Atrial Appendage Progenitor Cells.

High aldehyde dehydrogenase (ALDH &lt;sup&gt;hi&lt;/sup&gt; ) activity has been reported in normal and cancer stem cells. We and others have shown previously that human ALDH &lt;sup&gt;hi&lt;/sup&gt; cardiac atrial appendage cells are enriched with stem/progenitor cells. The role of ALDH in these cells is poorly understood but it may come down to the specific ALDH isoform(s) expressed. This study aimed to compare ALDH &lt;sup&gt;hi&lt;/sup&gt; and ALDH &lt;sup&gt;lo&lt;/sup&gt; atrial cells and to identify the isoform(s) that contribute to ALDH activity, and their functional role. &lt;b&gt;Methods and Results:&lt;/b&gt; Cells were isolated from atrial appendage specimens from patients with ischemic and/or valvular heart disease undergoing heart surgery. ALDH &lt;sup&gt;hi&lt;/sup&gt; activity assessed with the Aldefluor reagent coincided with primitive surface marker expression (CD34 &lt;sup&gt;+&lt;/sup&gt; ). Depending on their ALDH activity, RT-PCR analysis of ALDH &lt;sup&gt;hi&lt;/sup&gt; and ALDH &lt;sup&gt;lo&lt;/sup&gt; cells demonstrated a differential pattern of pluripotency genes (Oct 4, Nanog) and genes for more established cardiac lineages (Nkx2.5, Tbx5, Mef2c, GATA4). ALDH &lt;sup&gt;hi&lt;/sup&gt; cells, but not ALDH &lt;sup&gt;lo&lt;/sup&gt; cells, formed clones and were culture-expanded. When cultured under cardiac differentiation conditions, ALDH &lt;sup&gt;hi&lt;/sup&gt; cells gave rise to a higher number of cardiomyocytes compared with ALDH &lt;sup&gt;lo&lt;/sup&gt; cells. Among 19 ALDH isoforms known in human, ALDH1A3 was most highly expressed in ALDH &lt;sup&gt;hi&lt;/sup&gt; atrial cells. Knocking down ALDH1A3, but not ALDH1A1, ALDH1A2, ALDH2, ALDH4A1, or ALDH8A1 using siRNA decreased ALDH activity and cell proliferation in ALDH &lt;sup&gt;hi&lt;/sup&gt; cells. Conversely, overexpressing ALDH1A3 with a retroviral vector increased proliferation in ALDH &lt;sup&gt;lo&lt;/sup&gt; cells. &lt;b&gt;Conclusions:&lt;/b&gt; ALDH1A3 is the key isoform responsible for ALDH activity in ALDH &lt;sup&gt;hi&lt;/sup&gt; atrial appendage cells, which have a propensity to differentiate into cardiomyocytes. ALDH1A3 affects &lt;i&gt;in vitro&lt;/i&gt; proliferation of these cells

Development of a bilingual interdisciplinary scale assessing self-efficacy for participating in Medical Assistance in Dying

Medical Assistance in Dying (MAiD) is a complex process involving the person seeking care and their relatives. MAiD involves physical, psychosocial and spiritual needs, and consequently the involvement of an interdisciplinary team is beneficial. Therefore, updating the knowledge and skills of healthcare and social services professionals is critical. An interdisciplinary team from Laval University (Quebec, Canada) has developed a continuous training program for all health care and social services professionals who could be involved in the care of persons who request MAiD and their loved ones. It is crucial to assess whether the objectives of the continuous training program are being met, especially since this new training addresses several complex issues (legal, ethical, and clinical). Bandura's self-efficacy theory has been widely used to develop scales for assessing the impact of training programs and identifying knowledge gaps. Bandura's theory states that feeling secure in one's self-efficacy leads to self-determined motivation. Although there are various scales intended to measure self-efficacy in palliative care, none include self-efficacy for participating in the process surrounding MAiD. As a result, we aim to create a bilingual (English-French) interdisciplinary scale to assess self-efficacy for participating in the process surrounding MAiD. The scale will allow decision-makers and researchers to identify current knowledge gaps. It will also be useful for assessing the impact of current and future training programs addressing this end-of-life practice. In this work in progress, we briefly introduce the training program and the future steps in the development and validation of the scale

Development of a bilingual interdisciplinary scale assessing self-efficacy for participating in Medical Assistance in Dying

Medical Assistance in Dying (MAiD) is a complex process involving the person seeking care and their relatives. MAiD involves physical, psychosocial and spiritual needs, and consequently the involvement of an interdisciplinary team is beneficial. Therefore, updating the knowledge and skills of healthcare and social services professionals is critical. An interdisciplinary team from Laval University (Quebec, Canada) has developed a continuous training program for all health care and social services professionals who could be involved in the care of persons who request MAiD and their loved ones. It is crucial to assess whether the objectives of the continuous training program are being met, especially since this new training addresses several complex issues (legal, ethical, and clinical). Bandura's self-efficacy theory has been widely used to develop scales for assessing the impact of training programs and identifying knowledge gaps. Bandura's theory states that feeling secure in one's self-efficacy leads to self-determined motivation. Although there are various scales intended to measure self-efficacy in palliative care, none include self-efficacy for participating in the process surrounding MAiD. As a result, we aim to create a bilingual (English-French) interdisciplinary scale to assess self-efficacy for participating in the process surrounding MAiD. The scale will allow decision-makers and researchers to identify current knowledge gaps. It will also be useful for assessing the impact of current and future training programs addressing this end-of-life practice. In this work in progress, we briefly introduce the training program and the future steps in the development and validation of the scale

Importance du cytosquelette et des processus de phosphorylation/déphosphorylation des protéines dans la régulation fonctionnelle des canaux intercellulaires formés de connexine 43

Les jonctions gap (JG), zones spécialisées de la membrane plasmique où sont localisés des canaux intercellulaires (CJ), qui permettent le passage direct de cellule à cellule d'ions et de petites molécules. Dans le cœur, les JG permettent la synchronisation des activités électriques et donc des activités mécaniques, et leur dysfonctionnement est à l'origine de troubles du rythme cardiaque. Au cours de ce travail nous avons montré une implication du cytosquelette d'actine dans la régulation de l'activité des CJ composé de connexine 43. La régulation par les mécanismes de phosphorylation/déphosphorlation des protéines pourrait se faire soit par déphosphorylation directe des CJ, soit par l'intermédiaire d'une protéine régulatrice associée qui reste à déterminer. Nous avons également mis en évidence des propriétés indirectes d'un inhibiteur métabolique, l'antimycine A, qui est capable de provoquer la fermeture des CJ indépendamment des concentrations en calcium et en ATP intracellullaires.Gap junctions (GJ), specialised areas of membrane where intercellular channels (IC) are clustered, mediates the direct cell-to-cell exchange of small cytoplasmic molecules and of inorganic ions. In the heart, GJ form low-resistance pathway for cell-to-cell conduction of electrical impulses which mediates the synchronisation of electrical and mechanical activities. Dysfunctions of these GJ induce arrhythmias. In this study we demonstrate that actin cytoskeleton is involved in regulation of GJ channels made of connein 43. Regulation of GJ communication by phosphorylation/dephosphorylation processes can occur by dephosphorylating directly connexin 43 or a regulatory protein associated with gap junction channels. We also show that the metabolic inhibitor antymincine A, is able to directly interrupt cell-to-cell communication, even both ATP and calcium concentrations are kept stable.POITIERS-BU Sciences (861942102) / SudocSudocFranceF