GDF15 promotes weight loss by enhancing energy expenditure in muscle

Funding Information: We thank R. Seeley for sharing GFRAL-null mice; B. Lowell for sharing β-less mice; and J. Wu for shipping β-less mice to us. G.R.S. was supported by a Diabetes Canada Investigator Award (DI-5-17-5302-GS), a Canadian Institutes of Health Research Foundation Grant (201709FDN-CEBA-116200), a Tier 1 Canada Research Chair in Metabolic Diseases and a J. Bruce Duncan Endowed Chair in Metabolic Diseases; D.W. by Fellowship Grants from the McMaster Institute for Research on Aging (MIRA) at McMaster University; S.R. by a postdoctoral fellowship supported by MITACS and Novo Nordisk; L.K.T. by a CIHR Post-Doctoral Fellowship Award and Michael DeGroote Fellowship Award in Basic Biomedical Science; E.M.D. by a Vanier Canada Graduate Scholarship; G.P.H. by the Natural Sciences and Engineering Research Council of Canada (NSERC: 400362); G.J.D. and S.M.F. by NSERC-CGSM scholarships; L.D. by the Fonds de Recherche du Québec-Santé doctoral training award; D.P.B. by the GSK Chair in Diabetes of Université de Sherbrooke and a FRQS J1 salary award. The Genotype-Tissue Expression (GTEx) Project was supported by the Common Fund of the Office of the Director of the National Institutes of Health, and by the NCI, NHGRI, NHLBI, NIDA, NIMH and NINDS. Funding Information: S.B.J. and R.E.K. are employees of Novo Nordisk, a pharmaceutical company producing and selling medicine for the treatment of diabetes and obesity. G.R.S. is a co-founder and shareholder of Espervita Therapeutics. McMaster University has received funding from Espervita Therapeutics, Esperion Therapeutics, Poxel Pharmaceuticals and Nestle for research conducted in the laboratory of G.R.S. S.R. is supported by a MITACS postdoctoral fellowship sponsored by Novo Nordisk. H.C.G. holds the McMaster-Sanofi Population Health Institute Chair in Diabetes Research and Care. G.R.S., G.P. and H.C.G. are inventors listed on a patent for identifying GDF15 as a biomarker for metformin. G.R.S. has received consulting/speaking fees from Astra Zeneca, Eli Lilly, Esperion Therapeutics, Merck, Poxel Pharmaceuticals and Cambrian Biosciences. The other authors declare no competing interests. Publisher Copyright: © 2023, The Author(s).Peer reviewedPublisher PD

Study of the apelinergic system: Molecular determinants of biased signaling

Les principes de pharmacologie moderne suggèrent qu’en liant un récepteur à 7 domaines transmembranaires (7DTM), différents ligands peuvent activer préférentiellement l’une ou l’autre des voies signalétiques en aval du récepteur à l’étude. Afin d’appuyer ce concept de signalisation biaisée, aussi appelé sélectivité fonctionnelle, nous avons émis l’hypothèse que l’effet différentiel de deux ligands endogènes du récepteur APJ, soit l’apéline-13 et l’ELABELA, puisse découler des changements spatiotemporels de l’interactome protéique de ces complexes récepteur-ligand respectifs. Considérant que le récepteur APJ est exprimé in vivo de façon abondante chez les cellules endothéliales, notre objectif était aussi d’en identifier l’interactome propre à ce contexte cellulaire particulier. Afin de valider cette hypothèse, nous avons couplé le récepteur APJ avec une ascorbate peroxydase mutée (APEX2) pour effectuer un essai de proximité en surexprimant cette protéine chimérique chez des cellules endothéliales cardiaques de souris (MCEC) en culture. Nous avons confirmé, par buvardage à la streptavidine-HRP, l’efficacité de la biotinylation des protéines environnantes générée par le récepteur APJ-APEX2 en conditions basale et activée à l’apéline-13 ou l’ELABELA. La détection des étiquettes incluses de part et d’autre de la construction chimérique nous a permis de vérifier par immunobuvardage l’intégrité de celle-ci ainsi que la localisation cellulaire par microscopie confocale. Les protéines biotinylées ont été purifiées via des billes-streptavidine et détectées par spectrométrie de masse. Nos résultats d’analyse démontrent les partenaires d’interaction communs et distincts du récepteur APJ selon ses deux ligands endogènes indiquant une signalisation propre à chaque ligand. Nous avons également comparé nos résultats avec deux différentes bases de données d’interactions protéine-protéine pour y observer des différences et des similitudes. Nous retrouvons entre autres des protéines de mêmes familles pour l’ATPase vacuolaire et le complexe rétromère qui sont des protéines connues pour être impliquées dans la signalisation cellulaire des récepteurs à 7DTM. De plus, nous avons comparé les interactomes pour un même ligand selon les différents temps de stimulation qui révèle un changement dynamique de l’interactome du récepteur dans le temps. En somme, nos travaux démontrent pour la toute première fois l’interactome du récepteur APJ en condition basale et stimulée pour les deux ligands endogènes, l’Apéline-13 et l’ELABELA, dans des cellules endothéliales cardiaques de souris. La validation des partenaires de liaison dans le futur permettra d’approfondir nos connaissances au niveau de la signalisation du récepteur APJ.Abstract: The principles of modern pharmacology suggest that by binding a seven-transmembrane domain (7TM) receptor, different ligands can preferentially activate one or the other of the signaling pathways downstream of the receptor under study. In order to support this concept of biased signaling, also called functional selectivity, we hypothesized that the differential effect of two endogenous APJ receptor ligands, apelin-13 and ELABELA, may result from spatiotemporal changes of the protein interactome of these respective receptor-ligand complexes. Considering that the APJ receptor is abundantly expressed in vivo in endothelial cells, our objective was also to identify the interactome specific to this particular cellular context. In order to validate this hypothesis, we coupled the APJ receptor with a mutated ascorbate peroxidase (APEX2) to perform a proximity assay by overexpressing this chimeric protein in cultured mouse cardiac endothelial cells (MCEC). We have confirmed, by streptavidin-HRP blotting, the efficiency of biotinylation of the surrounding proteins generated by the APJ-APEX2 receptor under basal and activated conditions apelin-13 or ELABELA. The detection of the labels included on both sides of the chimeric construction allowed us to verify by immunoblotting the integrity of the protein as well as its cellular localization by confocal microscopy. The biotinylated proteins were purified via streptavidin beads and detected by mass spectrometry. Our analysis results demonstrate the common and distinct interaction partners of the APJ receptor according to its two endogenous ligands indicating a signaling specific to each ligand. We also compared our results with two different protein-protein interaction databases to find differences and similarities. Among other things, we have found proteins of the same family for vacuolar ATPase and the retromer complex which are proteins known to be involved in cellular signaling of 7TM receptor. In addition, we compared the interactomes for the same ligand according to the different stimulation times, which demonstrates a dynamic change in the receptor interactome over time. In short, our work demonstrates for the very first time the interactome of the APJ receptor in basal conditions and stimulated for the two endogenous ligands, Apelin-13 and ELABELA, in mouse cardiac endothelial cells. The validation of some of these newly identified protein partners in the future will allow us to deepen our knowledge in terms of APJ receptor signaling

The apelinergic system as an alternative to catecholamines in low-output septic shock

Abstract Catecholamines, in concert with fluid resuscitation, have long been recommended in the management of septic shock. However, not all patients respond positively and controversy surrounding the efficacy-to-safety profile of catecholamines has emerged, trending toward decatecholaminization. Contextually, it is time to re-examine the “maintaining blood pressure” paradigm by identifying safer and life-saving alternatives. We put in perspective the emerging and growing knowledge on a promising alternative avenue: the apelinergic system. This target exhibits invaluable pleiotropic properties, including inodilator activity, cardio-renal protection, and control of fluid homeostasis. Taken together, its effects are expected to be greatly beneficial for patients in septic shock

Additional file 1: Table S1. of Dual leucine zipper kinase regulates expression of axon guidance genes in mouse neuronal cells

Primers used in this study. (PDF 60 kb

Additional file 3: Table S3. of Dual leucine zipper kinase regulates expression of axon guidance genes in mouse neuronal cells

Genes up-regulated by two-fold or more in DLK-depleted cells. (PDF 103 kb