Role of inflammation and macrophages in early adaptive cardiac remodeling and transition towards heart failure

L’hypertrophie cardiaque est un processus adaptatif précoce permettant le maintien de la fonction cardiaque en réponse à une atteinte chronique ou aiguë. Cependant, la persistance du stress peut conduire, à long terme, à l’insuffisance cardiaque (IC). A ce jour, la compréhension des mécanismes impliqués dans le remodelage adaptatif demeure incomplète. Mon objectif de thèse a été d’identifier certains mécanismes moléculaires et cellulaires qui initient et régulent l’hypertrophie cardiaque adaptative (HCA) déclenchée par stimulation β-adrénergique. Ce travail établit le rôle essentiel de la protéine Orai3 dans le maintien de l’HCA et la protection contre l’évolution vers l’IC. Nous identifions la signalisation TNF-α/TNFR2 comme stimulus de l’influx calcique Orai3-dépendant dans les cardiomyocytes hypertrophiés, et montrons que les cellules immunes CD11b/c+ sont une source potentielle de TNF-α dans le cœur en HCA. Plus précisément, nous avons caractérisé les macrophages cardiaques présents dans le cœur sain, en HCA et en IC par des approches cytométrique, transcriptomique, sécrétomique et lipidomique. Nous montrons que l’expansion d’une population macrophagique au stade précoce du remodelage est essentielle à la réponse hypertrophique. Nos résultats identifient l’axe fractalkine/CX3CR1 comme signal médiateur clé de l’expansion de ces macrophages, de l’induction de l’HCA et de la protection contre l’IC. En résumé, ce travail renforce le concept selon lequel les cellules immunes influencent la réponse adaptative du cœur au stress en interagissant de façon paracrine avec les cardiomyocytes, et ouvre de nouvelles perspectives pour le traitement de l’IC.Cardiac hypertrophy is an early adaptive process to preserve cardiac function in response to chronic or acute injury. However, chronic excessive stress triggers transition to heart failure (HF). To date, mechanisms involved in early adaptive cardiac hypertrophy (EACH) are poorly understood. The aim of my PhD project was to identify molecular and cellular events that initiate and regulate EACH in response to β-adrenergic stimulation. My results establish the essential protective role of the Orai3 protein in EACH, limiting the evolution towards HF. We identify the TNF-α/TNFR2 signaling pathway as a stimulus of Orai3-dependent calcium influx in hypertrophied cardiomyocytes, and we show that CD11b/c+ immune cells are a potential source of TNF-α in EACH hearts. More specifically, we characterized cardiac macrophages from healthy, EACH and HF hearts using cytometric, transcriptomic, secretomic and lipidomic approaches. We show that a macrophage expansion during early stage of remodeling promotes the hypertrophic response. Our results identify the fractalkine/CX3CR1 axis as a key signal driving macrophage expansion, EACH induction and protection against HF. In summary, this work further strengthens the concept that immune cells influence the cardiac adaptive response to stress by paracrine interaction with cardiomyocytes and opens new perspectives for HF treatments

Transcriptomic and Lipidomic Mapping of Macrophages in the Hub of Chronic Beta-Adrenergic-Stimulation Unravels Hypertrophy-, Proliferation-, and Lipid Metabolism-Related Genes as Novel Potential Markers of Early Hypertrophy or Heart Failure

International audienceSympathetic nervous system overdrive with chronic release of catecholamines is the most important neurohormonal mechanism activated to maintain cardiac output in response to heart stress. Beta-adrenergic signaling behaves first as a compensatory pathway improving cardiac contractility and maladaptive remodeling but becomes dysfunctional leading to pathological hypertrophy and heart failure (HF). Cardiac remodeling is a complex inflammatory syndrome where macrophages play a determinant role. This study aimed at characterizing the temporal transcriptomic evolution of cardiac macrophages in mice subjected to beta-adrenergic-stimulation using RNA sequencing. Owing to a comprehensive bibliographic analysis and complementary lipidomic experiments, this study deciphers typical gene profiles in early compensated hypertrophy (ECH) versus late dilated remodeling related to HF. We uncover cardiac hypertrophy- and proliferation-related transcription programs typical of ECH or HF macrophages and identify lipid metabolism-associated and Na+ or K+ channel-related genes as markers of ECH and HF macrophages, respectively. In addition, our results substantiate the key time-dependent role of inflammatory, metabolic, and functional gene regulation in macrophages during beta-adrenergic dependent remodeling. This study provides important and novel knowledge to better understand the prevalent key role of resident macrophages in response to chronically activated beta-adrenergic signaling, an effective diagnostic and therapeutic target in failing hearts

Cardiac inflammatory CD11b/c cells exert a protective role in hypertrophied cardiomyocyte by promoting TNFR2- and Orai3- dependent signaling

International audienceAbstract Early adaptive cardiac hypertrophy (EACH) is initially a compensatory process to optimize pump function. We reported the emergence of Orai3 activity during EACH. This study aimed to characterize how inflammation regulates store-independent activation of Orai3-calcium influx and to evaluate the functional role of this influx. Isoproterenol infusion or abdominal aortic banding triggered EACH. TNFα or conditioned medium from cardiac CD11b/c cells activated either in vivo [isolated from rats displaying EACH], or in vitro [isolated from normal rats and activated with lipopolysaccharide], were added to adult cardiomyocytes before measuring calcium entry, cell hypertrophy and cell injury. Using intramyocardial injection of siRNA, Orai3 was in vivo knockdown during EACH to evaluate its protective activity in heart failure. Inflammatory CD11b/c cells trigger a store-independent calcium influx in hypertrophied cardiomyocytes, that is mimicked by TNFα. Pharmacological or molecular (siRNA) approaches demonstrate that this calcium influx, depends on TNFR 2 , is Orai3-driven, and elicits cardiomyocyte hypertrophy and resistance to oxidative stress. Neutralization of Orai3 inhibits protective GSK3β phosphorylation, impairs EACH and accelerates heart failure. Orai3 exerts a pathophysiological protective impact in EACH promoting hypertrophy and resistance to oxidative stress. We highlight inflammation arising from CD11b/c cells as a potential trigger of TNFR 2 - and Orai3-dependent signaling pathways

Cardiac inflammatory CD11b/c cells exert a protective role in hypertrophied cardiomyocyte by promoting TNFR2- and Orai3- dependent signaling

Abstract Early adaptive cardiac hypertrophy (EACH) is initially a compensatory process to optimize pump function. We reported the emergence of Orai3 activity during EACH. This study aimed to characterize how inflammation regulates store-independent activation of Orai3-calcium influx and to evaluate the functional role of this influx. Isoproterenol infusion or abdominal aortic banding triggered EACH. TNFα or conditioned medium from cardiac CD11b/c cells activated either in vivo [isolated from rats displaying EACH], or in vitro [isolated from normal rats and activated with lipopolysaccharide], were added to adult cardiomyocytes before measuring calcium entry, cell hypertrophy and cell injury. Using intramyocardial injection of siRNA, Orai3 was in vivo knockdown during EACH to evaluate its protective activity in heart failure. Inflammatory CD11b/c cells trigger a store-independent calcium influx in hypertrophied cardiomyocytes, that is mimicked by TNFα. Pharmacological or molecular (siRNA) approaches demonstrate that this calcium influx, depends on TNFR2, is Orai3-driven, and elicits cardiomyocyte hypertrophy and resistance to oxidative stress. Neutralization of Orai3 inhibits protective GSK3β phosphorylation, impairs EACH and accelerates heart failure. Orai3 exerts a pathophysiological protective impact in EACH promoting hypertrophy and resistance to oxidative stress. We highlight inflammation arising from CD11b/c cells as a potential trigger of TNFR2- and Orai3-dependent signaling pathways

Tocolysis after preterm premature rupture of membranes and neonatal outcome: a propensity-score analysis

International audienceBackground: There are conflicting results regarding tocolysis in cases of preterm premature rupture of membranes. Delaying delivery may reduce neonatal morbidity because of prematurity and allow for prenatal corticosteroids and, if necessary, in utero transfer. However, that may increase the risks of maternofetal infection and its adverse consequences.Objective: The objective of the study was to investigate whether tocolytic therapy in cases of preterm premature rupture of membranes is associated with improved neonatal or obstetric outcomes.Study Design: Etude Epidémiologique sur les Petits Ages Gestationnels 2 is a French national prospective, population-based cohort study of preterm births that occurred in 546 maternity units in 2011. Inclusion criteria in this analysis were women with preterm premature rupture of membranes at 24–32 weeks’ gestation and singleton gestations. Outcomes were survival to discharge without severe morbidity, latency prolonged by ≥48 hours and histological chorioamnionitis. Uterine contractions at admission, individual and obstetric characteristics, and neonatal outcomes were compared by tocolytic treatment or not. Propensity scores and inverse probability of treatment weighting for each woman were used to minimize indication bias in estimating the association of tocolytic therapy with outcomes.Results: The study population consisted of 803 women; 596 (73.4%) received tocolysis. Women with and without tocolysis did not differ in neonatal survival without severe morbidity (86.7% vs 83.9%, P = .39), latency prolonged by ≥48 hours (75.1% vs 77.4%, P = .59), or histological chorioamnionitis (50.0% vs 47.6%, P = .73). After applying propensity scores and assigning inverse probability of treatment weighting, tocolysis was not associated with improved survival without severe morbidity as compared with no tocolysis (odds ratio, 1.01 [95% confidence interval, 0.94–1.09], latency prolonged by ≥48 hours (1.03 [95% confidence interval, 0.95–1.11]), or histological chorioamnionitis (1.03 [95% confidence interval, 0.92–1.17]). There was no association between the initial tocolytic drug used (oxytocin receptor antagonists or calcium-channel blockers vs no tocolysis) and the 3 outcomes. Sensitivity analyses of women with preterm premature rupture of membranes at 26–31 weeks’ gestation, women who delivered at least 12 hours after rupture of membranes, women with direct admission after the rupture of membranes and the presence or absence of contractions gave similar results.Conclusion: Tocolysis in cases of preterm premature rupture of membranes is not associated with improved obstetric or neonatal outcomes; its clinical benefit remains unproven

CRISPR/Cas9 Editing of the Mouse Thra Gene Produces Models with Variable Resistance to Thyroid Hormone

International audienceResistance to thyroid hormone due to THRA mutations (RTHα) is a recently discovered genetic disease, displaying important variability in its clinical presentation. The mutations alter the function of TRα1, one of the two nuclear receptors for thyroid hormone

iGEM REPORT: Gotta Detect ‘Em All: a multi-STI sensor based on aptamers

/International audienceNowadays, STIs constitute a major public health issue. Indeed, treatments are often started too late because of belated diagnosis resulting in health problems, such as sterility. If prevention is probably the most effective action one can take to prevent the spread of STIs, early detection could help limit their deleterious effects. In this work, a new diagnosis approach based on aptamers is presented. Bound to paper, they allow the detection of HIV and Hepatitis B biomarkers from a blood sample. The associated device is composed of an anchor, the streptavidin protein, allowing the fixation of the aptamer to the paper via biotin (see graphical abstract). With this system, the HIV-1 Reverse Transcriptase (BBa_K1934060 and BBa_K1934061: protein subunits p51 and p66) and HBsAg (surface antigen of Hepatitis B) are specifically targeted. Then, the biomarker/aptamer complex is detected by two methods. The first one is based on fluorescence. As a proof of concept, a paired ATP/aptamer was used and enabled to successfully detect ATP up to 10 µmol.L-1. However, the signal was not detectable with naked eyes or with a cell phone equipped with blue and green filters either. Therefore, a lateral flow assay with nano-sized latex black beads was tested. This second technique showed that a protein biomarker, such as thrombin, could be complexed with latex beads coated with aptamers, in liquid. Finally, the ultimate step, migration of the latex beads inside paper, needs further optimization. Moreover, to easily handle several STI-tests on a single paper strip, an innovative bio-sourced PLA casing was designed and 3D printed to offer an additional intuitive user-interface

iGEM REPORT: Gotta Detect ‘Em All: a multi-STI sensor based on aptamers

/International audienceNowadays, STIs constitute a major public health issue. Indeed, treatments are often started too late because of belated diagnosis resulting in health problems, such as sterility. If prevention is probably the most effective action one can take to prevent the spread of STIs, early detection could help limit their deleterious effects. In this work, a new diagnosis approach based on aptamers is presented. Bound to paper, they allow the detection of HIV and Hepatitis B biomarkers from a blood sample. The associated device is composed of an anchor, the streptavidin protein, allowing the fixation of the aptamer to the paper via biotin (see graphical abstract). With this system, the HIV-1 Reverse Transcriptase (BBa_K1934060 and BBa_K1934061: protein subunits p51 and p66) and HBsAg (surface antigen of Hepatitis B) are specifically targeted. Then, the biomarker/aptamer complex is detected by two methods. The first one is based on fluorescence. As a proof of concept, a paired ATP/aptamer was used and enabled to successfully detect ATP up to 10 µmol.L-1. However, the signal was not detectable with naked eyes or with a cell phone equipped with blue and green filters either. Therefore, a lateral flow assay with nano-sized latex black beads was tested. This second technique showed that a protein biomarker, such as thrombin, could be complexed with latex beads coated with aptamers, in liquid. Finally, the ultimate step, migration of the latex beads inside paper, needs further optimization. Moreover, to easily handle several STI-tests on a single paper strip, an innovative bio-sourced PLA casing was designed and 3D printed to offer an additional intuitive user-interface

iGEM REPORT: Gotta Detect ‘Em All: a multi-STI sensor based on aptamers

/International audienceNowadays, STIs constitute a major public health issue. Indeed, treatments are often started too late because of belated diagnosis resulting in health problems, such as sterility. If prevention is probably the most effective action one can take to prevent the spread of STIs, early detection could help limit their deleterious effects. In this work, a new diagnosis approach based on aptamers is presented. Bound to paper, they allow the detection of HIV and Hepatitis B biomarkers from a blood sample. The associated device is composed of an anchor, the streptavidin protein, allowing the fixation of the aptamer to the paper via biotin (see graphical abstract). With this system, the HIV-1 Reverse Transcriptase (BBa_K1934060 and BBa_K1934061: protein subunits p51 and p66) and HBsAg (surface antigen of Hepatitis B) are specifically targeted. Then, the biomarker/aptamer complex is detected by two methods. The first one is based on fluorescence. As a proof of concept, a paired ATP/aptamer was used and enabled to successfully detect ATP up to 10 µmol.L-1. However, the signal was not detectable with naked eyes or with a cell phone equipped with blue and green filters either. Therefore, a lateral flow assay with nano-sized latex black beads was tested. This second technique showed that a protein biomarker, such as thrombin, could be complexed with latex beads coated with aptamers, in liquid. Finally, the ultimate step, migration of the latex beads inside paper, needs further optimization. Moreover, to easily handle several STI-tests on a single paper strip, an innovative bio-sourced PLA casing was designed and 3D printed to offer an additional intuitive user-interface

iGEM REPORT: Gotta Detect ‘Em All: a multi-STI sensor based on aptamers

/International audienceNowadays, STIs constitute a major public health issue. Indeed, treatments are often started too late because of belated diagnosis resulting in health problems, such as sterility. If prevention is probably the most effective action one can take to prevent the spread of STIs, early detection could help limit their deleterious effects. In this work, a new diagnosis approach based on aptamers is presented. Bound to paper, they allow the detection of HIV and Hepatitis B biomarkers from a blood sample. The associated device is composed of an anchor, the streptavidin protein, allowing the fixation of the aptamer to the paper via biotin (see graphical abstract). With this system, the HIV-1 Reverse Transcriptase (BBa_K1934060 and BBa_K1934061: protein subunits p51 and p66) and HBsAg (surface antigen of Hepatitis B) are specifically targeted. Then, the biomarker/aptamer complex is detected by two methods. The first one is based on fluorescence. As a proof of concept, a paired ATP/aptamer was used and enabled to successfully detect ATP up to 10 µmol.L-1. However, the signal was not detectable with naked eyes or with a cell phone equipped with blue and green filters either. Therefore, a lateral flow assay with nano-sized latex black beads was tested. This second technique showed that a protein biomarker, such as thrombin, could be complexed with latex beads coated with aptamers, in liquid. Finally, the ultimate step, migration of the latex beads inside paper, needs further optimization. Moreover, to easily handle several STI-tests on a single paper strip, an innovative bio-sourced PLA casing was designed and 3D printed to offer an additional intuitive user-interface