Differential β₂-adrenergic receptor expression defines the phenotype of non-tumorigenic and malignant human breast cell lines

Breast cancer is the most frequent malignancy in women. Several reports demonstrated that adrenergic receptors (ARs) are involved in breast cancer. Here we observed that epinephrine (Epi), an endogenous AR agonist, caused opposite effects in non-tumorigenic (MCF-10A and HBL-100) and tumor cells (MCF-7 and MDA-MB-231). Thus, Epi, in non-tumor breast cells, as well as isoproterenol (β-agonist), in all cell lines, maintained a benign phenotype, decreasing cell proliferation and migration, and stimulating cell adhesion. β-AR expression and cAMP levels were higher in MCF-10A than in MCF-7 cells. β₂-AR knock-down caused a significant increase of cell proliferation and migration, and a decrease of cell adhesion both in basal and in Iso-stimulated conditions. Coincidently, β₂-AR over-expression induced a significant decrease of cell proliferation and migration, and an increase of cell adhesion. Therefore, β₂-AR is implied in cell phenotype and its agonists or antagonists could eventually complement cancer therapy.Fil: Gargiulo, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Copsel, Sabrina Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Rivero, Ezequiel Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Galés, Céline. Inserm; FranciaFil: Sénard, Jean Michel. Inserm; FranciaFil: Luthy, Isabel Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Davio, Carlos Alberto. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Bruzzone, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Monitoring Cognitive and Emotional Processes Through Pupil and Cardiac Response During Dynamic Versus Logical Task

The paper deals with the links between physiological measurements and cognitive and emotional functioning. As long as the operator is a key agent in charge of complex systems, the definition of metrics able to predict his performance is a great challenge. The measurement of the physiological state is a very promising way but a very acute comprehension is required; in particular few studies compare autonomous nervous system reactivity according to specific cognitive processes during task performance and task related psychological stress is often ignored. We compared physiological parameters recorded on 24 healthy subjects facing two neuropsychological tasks: a dynamic task that require problem solving in a world that continually evolves over time and a logical task representative of cognitive processes performed by operators facing everyday problem solving. Results showed that the mean pupil diameter change was higher during the dynamic task; conversely, the heart rate was more elevated during the logical task. Finally, the systolic blood pressure seemed to be strongly sensitive to psychological stress. A better taking into account of the precise influence of a given cognitive activity and both workload and related task-induced psychological stress during task performance is a promising way to better monitor operators in complex working situations to detect mental overload or pejorative stress factor of error

Interest of alpha2-adrenergic agonists and antagonists in clinical practice: background, facts and perspectives.

International audienceThe family of alpha(2)-adrenergic receptors (alpha(2)-ARs) comprises three subtypes which are each endowed with specific functions. alpha(2)-agonists and alpha(2)-antagonists are part of the clinician armamentarium since several decades; however, none of the compounds so far available is subtype selective. For long, clonidine and yohimbine have been used for the treatment of hypertension and impotence respectively, but both have been superseded by newer drugs. This review attempts, by a comprehensive analysis of the literature, to cover the present clinical use and the potential therapeutic interest of alpha(2)-agonists or antagonists. From the clinical data, it is concluded that, with the exception of a few particular situations, alpha(2)-agonists are only of limited utility as a monotherapy. By contrast, they offer several powerful advantages when used in adjunctive therapy. In perioperative settings, alpha(2)-agonists are extremely valuable adjuncts to anesthetics and analgesics for the induction of anxiolysis, maintenance of sedation, management of pain and prevention of shivering. In the ophthalmic clinic, they are used to lower intra-ocular pressure during laser surgery of the eye. As a daily medication, alpha(2)-agonists are also of interest for the treatment of glaucoma, muscle spasticity, opiate withdrawal, and behavior disorders. The alpha(2)-antagonists are useful antidotes for reversing the threatening effects of agonist overdose, but currently there are very few indications. New applications are under investigation, and new molecules with more refined subtype-selectivity may emerge, so the clinical utility of both alpha(2)-agonists and antagonists will undoubtedly expand in the future

Probing heterotrimeric G protein activation: applications to biased ligands.

International audienceCell surface G protein-coupled receptors (GPCRs) drive numerous signaling pathways involved in the regulation of a broad range of physiologic processes. Today, they represent the largest target for modern drugs development with potential application in all clinical fields. Recently, the concept of "ligand-directed trafficking" has led to a conceptual revolution in pharmacological theory, thus opening new avenues for drug discovery. Accordingly, GPCRs do not function as simple on-off switch but rather as filters capable of selecting the activation of specific signals and thus generating texture responses to ligands, a phenomenon often referred to as ligand-biased signaling. Also, one challenging task today remains optimization of pharmacological assays with increased sensitivity so to better appreciate the inherent texture of ligands. However, considering that a single receptor has pleiotropic signaling properties and that each signal can crosstalk at different levels, biased activity remains thus difficult to evaluate. One strategy to overcome these limitations would be examining the initial steps following receptor activation. Even, if some G protein independent functions have been recently described, heterotrimeric G protein activation remains a general hallmark for all GPCRs families and the first cellular event subsequent to agonist binding to the receptor. Herein, we review the different methodologies classically used or recently developed to monitor G protein activation and discussed them in the context of G protein biased-ligands

Le réveil des cardiomyocytes adultes résidents

Les pathologies cardiaques, et en particulier l’infarctus du myocarde, conduisent inéluctablement à la mort des cardiomyocytes adultes favorisant le développement de l’insuffisance cardiaque. Les efforts en médecine cardiaque régénératrice se sont concentrés jusqu’à présent sur l’utilisation des cellules souches, laissant de côté les cardiomyocytes préexistants, considérés comme étant dans un état postmitotique. Néanmoins, des données récentes obtenues chez le poisson zèbre et les mammifères relancent le débat sur la capacité proliférative de ces cellules. Dans cette revue, nous proposons un état des lieux des connaissances de la capacité proliférative et régénératrice des cardiomyocytes résidents, et discutons certains aspects mécanistiques. Dans le futur, l’identification précise des mécanismes moléculaires permettant à ces cellules de reprendre leur prolifération devrait permettre d’ouvrir de nouvelles perspectives thérapeutiques en régénération cardiaque

Étude pharmacoépidémiologique française de l'utilisation des triptans en médecine générale

Cette étude pharmacoépidémiologique décrit l'utilisation des triptans en médecine générale, auprès de migraineux "naïfs" (n'ayant jamais utilisé un triptan) et "non naïfs" de triptans (expérience antérieure d'un traitement par cette classe thérapeutique). Elle montre que 95 % des patients inclus sont migraineux selon les critères de l'International Headache Society (IHS), ce qui confirme le bon usage des triptans en médecine générale. Les patients bénéficiant de triptans sont des migraineux ayant un profil de sévérité supérieur à celui des migraineux en population générale. Les patients "naïfs" et "non naïfs" ont un profil comparable en termes de diagnostic IHS et de sévérité de la maladie mais les patients "non naïfs" ont une histoire de la maladie plus ancienne et un impact plus marqué sur la qualité de vie. Les raisons des modifications de traitements avancées le plus fréquemment sont la recherche d'une meilleure efficacité de leur nouveau traitement, une action plus rapide, une moindre récurrence et une meilleure tolérance

Dosage-dependent regulation of cell prolifration and adhesion through dual beta2-adrenergic receptor/cAMP signals

The role of Beta-adrenergic receptors (B-ARs) remains controversial in normal and tumor breast. Herein we explore the cAMP signaling involved in B-AR-dependent control of proliferation and adhesion of nontumor human breast cell line MCF-10A. Low concentrations of a B-agonist, isoproterenol (ISO), promote cell adhesion (87.5% cells remaining adherent to the plastic dishes following specific detachment vs. 35.0% in control, P 0.001), while increasing concentrations further engages an additional 36% inhibition of Erk1/2 phosphorylation (p-Erk1/2) -dependent cell proliferation (P 0.01). Isoproterenol dose response on cell adhesion was fitted to a 2-site curve (EC50(1): 16.5 +/-11.5 fM, EC50(2): 4.08 +/- 3.09 nM), while ISO significantly inhibited p-Erk1/2 according to a 1-site model (EC50: 0.25 +/- 0.13 nM). Using B-AR-selective agonist/antagonists and cAMP analogs/inhibitors, we identified a dosage-dependent signaling in which low ISO concentrations target a B2-AR population localized in raft microdomains and stimulate a Gs/cAMP/Epac/adhesion-signaling module, while higher concentrations engage a concomitant activation of another B2-AR population outside rafts and inhibit the proliferation by a Gs/cAMP/PKA-dependent signaling module. Our data provide a new molecular basis for the dose-dependent switch of B-AR signaling. This study also sheds light on a new cAMP pathway core mechanism with a single receptor triggering dual cAMP signaling controlled by PKA or Epac but with different cellular outputs.Fil: Bruzzone, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Saulière, Aude. Inserm; FranciaFil: Finana, Frédéric . Institut de Recherche Pierre Fabre; FranciaFil: Sénard, Jean Michel. Inserm; Francia. Toulouse University Hospital; FranciaFil: Luthy, Isabel Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Galés, Céline. Inserm; Franci

Atomic force microscopy-single-molecule force spectroscopy unveils GPCR cell surface architecture

International audienceG protein-coupled receptors (GPCRs) form the largest family of cell surface receptors. Despite considerable insights into their pharmacology, the GPCR architecture at the cell surface still remains largely unexplored. Herein, we present the specific unfolding of different GPCRs at the surface of living mammalian cells by atomic force microscopy-based single molecule force spectroscopy (AFM-SMFS). Mathematical analysis of the GPCR unfolding distances at resting state revealed the presence of different receptor populations relying on distinct oligomeric states which are receptor-specific and receptor expression-dependent. Moreover, we show that the oligomer size dictates the receptor spatial organization with nanoclusters of high-order oligomers while lower-order complexes spread over the whole cell surface. Finally, the receptor activity reshapes both the oligomeric populations and their spatial arrangement. These results add an additional level of complexity to the GPCR pharmacology until now considered to arise from a single receptor population at the cell surface.Atomic force microscopy-based single molecule force spectroscopy reveals the unfolding of G-protein coupled receptors on the surface of living mammalian cells

Short-term effects of a 3-week interval training program on heart rate variability in chronic heart failure. A randomised controlled trial

International audienceBackground: Exaggerated sympathetic nervous system activity associated with low heart rate variability (HRV) is considered to trigger cardiac arrhythmias and sudden death. Regular exercise training is efficient to improve autonomic balance.Objective: We aimed to verify the superiority of high-intensity interval training (HIIT) to enhance HRV, cardiorespiratory fitness and cardiac function as compared with moderate intensity continuous training (MICT) in a short, intense cardiac rehabilitation program.Methods: This was a prospective, monocentric, evaluator-blinded, randomised (1:1) study with a parallel two-group design. Overall, 31 individuals with voluntary chronic heart failure (CHF) (left ventricular ejection fraction [LVEF]<45%) were allocated to MICT (n=15) or HIIT (n=16) for a short rehabilitation program (mean [SD] 27 [4] days). Participants underwent 24-hr electrocardiography, echocardiography and a cardiopulmonary exercise test at entry and at the end of the study.Results: High-frequency power in normalized units (HFnu%) measured as HRV increased with HIIT (from 21.2% to 26.4%, P<0.001) but remained unchanged with MICT (from 23.1% to 21.9%, P=0.444, with a significant intergroup difference, P=0.003). Resting heart rate (24-hr Holter electrocardiography) decreased significantly for both groups (from 68.2 to 64.6 bpm and 66.0 to 63.5 bpm for MICT and HIIT, respectively, with no intergroup difference, P=0.578). The 2 groups did not differ in premature ventricular contractions. Improvement in peak oxygen uptake was greater with HIIT than MICT (+21% vs. +5%, P=0.009). LVEF improved with only HIIT (from 36.2% to 39.5%, P=0.034).Conclusions: In this short rehabilitation program, HIIT was significantly superior to the classical MICT program for enhancing parasympathetic tone and peak oxygen uptake. CLINICALTRIALS.Gov identifier: NCT03603743