Biology subjects

Verano-Braga, T.

Publications and source records attributed to Verano-Braga, T..

7 recordsLinked to original sources

bioRxiv2026

Oral administration of Angiotensin-(1-7) included in hydroxypropyl β-cyclodextrin attenuates cardiac hypertrophy and inflammation in a mouse model of Takotsubo cardiomyopathy

Background Takotsubo cardiomyopathy (TTC) is a stress-induced cardiomyopathy characterized by acute cardiac dysfunction, inflammation, and hypertrophy, yet no therapy directly targets the underlying myocardial injury. Clinical studies have reported elevated circulating Angiotensin II (Ang II) levels in TTC patients, suggesting dysregulation of the renin-angiotensin system (RAS). Given the established cardioprotective effects of Angiotensin-(1-7) [Ang-(1-7)] in other cardiovascular diseases, we hypothesized that oral administration of Ang-(1-7) could attenuate acute cardiac remodeling during TTC. Methods Female C57BL/6J mice were subjected to a single high-dose isoproterenol (ISO) injection (300 mg/Kg, intraperitoneal) to induce TTC and received daily oral treatment with Ang-(1-7) complexed with hydroxypropyl {beta}-cyclodextrin [Ang-(1-7)-CD] or vehicle (CD), for 4 days, beginning one day before ISO administration. Cardiac proteome alterations were characterized by tandem mass tag (TMT)-based quantitative proteomics. Cardiac hypertrophy was assessed by heart weight normalized to tibial length and cardiomyocyte cross-sectional area. Myocardial inflammation was evaluated by histopathology, CD68 immunostaining, and flow cytometric analysis of infiltrating leukocyte populations. Results We observed a distinct cardiac proteome signature in Ang-(1-7)-treated ISO mice, predicting inhibition of pathways associated with cardiac hypertrophy and adverse remodeling. These molecular changes were accompanied by reduced heart weight normalized to tibial length and smaller cardiomyocyte cross-sectional area compared with vehicle-treated ISO mice. Oral Ang-(1-7) also attenuated myocardial inflammation, as evidenced by lower inflammatory scores, reduced CD68+ macrophage infiltration, decreased numbers of CD45+ leukocytes, and marked suppression of Ly6G+ neutrophil and CCR2+ monocyte recruitment to the heart. These protective effects were associated with improved survival following ISO challenge. MS data are available via ProteomeXchange (PXD082872). Conclusions Oral administration of Ang-(1-7) attenuated acute cardiac hypertrophy and inflammation in experimental TTC while inducing cardiac proteome changes consistent with reduced adverse remodeling. These findings identify activation of the protective RAS axis as a promising therapeutic strategy for limiting myocardial injury during TTC.

physiology↗

bioRxiv2025

MrgD Receptor Modulates Neurotransmission in the Nigrostriatal Pathway

The Mas-related G protein-coupled receptor D (MrgD) is primarily known for its role in peripheral nociception and, more recently, as a receptor for alamandine, influencing cardiovascular function and exhibiting antidepressant-like effects. However, its function within the central nervous system, particularly in motor and reward-related circuits, remains largely unexplored. Here, we investigate the role of MrgD in the nigrostriatal pathway using proteomic approaches focused on post-translational modifications in MrgD-knockout (KO) mice. Integrated proteomic, phosphoproteomic, and N-glycoproteomic analyses revealed significant alterations in synaptic vesicle-associated proteins, pointing to impaired neurotransmission in the nigrostriatal system of KO mice. These molecular findings were supported by neurotransmitter quantification and functional assays demonstrating impaired synaptic vesicle exocytosis. Pharmacodynamic analyses showed that MrgD modulates synaptic exocytosis in an agonist-selective manner, being responsive to alamandine but not {beta}-alanine. Furthermore, behavioral analyses revealed increased locomotor activity and compulsive-like behavior in MrgD-deficient mice, without impairments in short- or long-term memory. Together, these findings uncover a new role for MrgD beyond its involvement in nociception, highlighting this receptor as a potential therapeutic target for neurological disorders involving motor hyperactivity and compulsivity.

neuroscience↗

bioRxiv2024

Identification and characterization of alamandine-(1-5), a new component of the Renin-Angiotensin System with unique properties

The renin-angiotensin system (RAS) comprises a biochemical cascade that hydrolyzes angiotensinogen into several different bioactive peptides, which can activate different receptors promoting plenty of specific effects. The aim of this study was to evaluate the presence of the putative product of alamandine, the pentapeptide alamandine-(1-5) in the circulation and its biological activity. To accomplish this we have used mass spectrometry (MALDI/TOF/TOF, LC-MS/MS) and several methodologies including isolated blood vessels, isolated perfused hearts, isolated cardiomyocytes, blood pressure recording in freely-moving normotensive and hypertensive rats (SHR), high resolution echocardiography (VEVO 2100), central administration (ICV infusion and microinjection in the insular cortex), cell culture (endothelial cells and GPCR-transfected CHO cells) and wild type and Mas, MrgD or AT2R deficient mice. Our results show that alamandine-(1-5) circulates in the human and rodent blood and promotes many biological central and peripheral actions. More importantly, its plasma concentration is increased in pediatric nephropathic patients. A major role for plasma ACE activity in the formation of alamandine-(1-5) from alamandine was observed using plasma samples from Angiotensinogen-KO mice. Alamandine-(1-5) increased Baroreflex sensitivity and produced a long-lasting ([~]6 hours) anti-hypertensive effect in SHR, associated with a significant reduction in cardiac output. A particularly important effect of this pentapeptide was observed in isolated perfused heart and cardiomyocyte contractility (reduced inotropism). It was capable of stimulating NO production through all receptors from the renin-angiotensin protective arm, (MAS, MrgD and AT2R) in CHO-transfected cells. Our data shows that Alamandine-(1-5) exhibits selective actions that set it apart from traditional concepts of the vasodilatory axis of the RAS and that are possibly intricately linked to a complex interplay between Mas, MrgD and AT2 receptors. This novel finding suggests that RAS may possess a complexity that surpasses our current understanding.

physiology↗

bioRxiv2024

Angiotensin-(1-5) is a Potent Endogenous Angiotensin AT2-Receptor Agonist

BackgroundThe renin-angiotensin system involves many more enzymes, receptors and biologically active peptides than originally thought. With this study, we investigated whether angiotensin-(1-5) [Ang-(1-5)], a 5-amino acid fragment of angiotensin II, has biological activity, and through which receptor it elicits effects. MethodsThe effect of Ang-(1-5) (1{micro}M) on nitric oxide release was measured by DAF-FM staining in human aortic endothelial cells (HAEC), or Chinese Hamster Ovary (CHO) cells stably transfected with the angiotensin AT2-receptor (AT2R) or the receptor Mas. A potential vasodilatory effect of Ang-(1-5) was tested in mouse mesenteric and human renal arteries by wire myography; the effect on blood pressure was evaluated in normotensive C57BL/6 mice by Millar catheter. These experiments were performed in the presence or absence of a range of antagonists or inhibitors or in AT2R-knockout mice. Binding of Ang-(1-5) to the AT2R was confirmed and the preferred conformations determined by in silico docking simulations. The signaling network of Ang-(1-5) was mapped by quantitative phosphoproteomics. ResultsKey findings included: (1) Ang-(1-5) induced activation of eNOS by changes in phosphorylation at Ser1177eNOS and Tyr657eNOS and thereby (2) increased NO release from HAEC and AT2R-transfected CHO cells, but not from Mas-transfected or non-transfected CHO cells. (3) Ang-(1-5) induced relaxation of preconstricted mouse mesenteric and human renal arteries and (4) lowered blood pressure in normotensive mice - effects which were respectively absent in arteries from AT2R-KO or in PD123319-treated mice and which were more potent than effects of the established AT2R-agonist C21. (5) According to in silico modelling, Ang-(1-5) binds to the AT2R in two preferred conformations, one differing substantially from where the first five amino acids within angiotensin II bind to the AT2R. (6) Ang-(1-5) modifies signaling pathways in a protective RAS-typical way and with relevance for endothelial cell physiology and disease. ConclusionsAng-(1-5) is a potent, endogenous AT2R-agonist.

pharmacology and toxicology↗

bioRxiv2024

Evidence that the monoamine oxidase B (MAO-B) plays a central role in the inotropic dysfunction induced by genetic deletion of the Mas-related-G protein-coupled receptor D (MrgD) in mice

The renin-angiotensin system (RAS) plays a critical role in the regulation of the cardiovascular system. The Mas-related G protein receptor member D (MrgD) is the receptor of alamandine, and both are components of the RAS noncanonical arm. Alamandine/MrgD induces vasodilation, anti-inflammatory, anti-fibrotic and anti-oxidative effects. In contrast, Mrgd gene deletion leads to a remarkable dilated cardiomyopathy (DCM) in mice. Here, we aimed to investigate the molecular mechanisms of DCM triggered by the deletion of MrgD in the left ventricle and isolated ventricular cardiomyocytes from 8-12 weeks old mice using phosphoproteomics. Our findings revealed an increased oxidative stress not caused by angiotensin II/AT1 hyperactivation but instead due to the up-regulation of the monoamine oxidase B (MAO-B), leading to a higher catabolism of dopamine and epinephrine in the MrgD-KO cardiac tissues. The oxidative environment induced by MAO-B hyperactivation seems to be the cause of the observed alteration in ionic dynamics - altered Ca2+ transient and Na+/K+-ATPase activity - leading to altered resting membrane potential (RMP) and decreased contraction of MrgD-KO cardiomyocytes. In addition, cardiac Troponin-I phosphorylation, and Titin dephosphorylation seem to contribute to the contractile dysfunction observed in MrgD-KO. The treatment of cardiomyocytes from MrgD-KO mice with the MAO-B inhibitor Pargyline reverted the observed impaired contraction, corroborating the hypothesis that MAO-B hyperactivation is, at least partially, the cause of the failing heart observed in MrgD-KO mouse. The findings reported here provide important insights into the pathogenesis of heart failure and suggest a potential therapeutic target (MrgD activation) for managing failing hearts.

physiology↗

bioRxiv2023

Vagus nerve mediated liver-brain axis is a major regulator of the metabolic landscape in the liver

BackgroundThe liver serves as a major energetic reservoir for other tissues and its metabolic function is controlled by humoral and neural factors. The vagus nerve innervating the gastrointestinal tract plays an important role in regulating peripheral metabolism and energy expenditure. Although the liver receives vagus nerve fibers, the impact of this circuitry in the regulation of hepatic metabolism is still poorly understood. MethodsHerein, we used a combination of quantitative proteomics and in vivo imaging techniques to investigate the impact of the vagus nerve on liver metabolism. ResultsVagus nerve shapes the metabolic framework of the liver, as surgical ablation (vagotomy; VNX) of this circuitry led to a significant alteration of the hepatic proteome landscape. Differential protein expression and pathway enrichment analyses showed that glycolytic and fatty acid biosynthesis were increased following VNX, whereas {beta}-oxidation was decreased. This metabolic shift facilitated lipid accumulation in hepatocytes. Furthermore, VNX worsened liver steatosis following high-carbohydrate or high-fat dietary challenges. ConclusionsThis study describes the liver-brain axis mediated by the vagus nerve as an important regulator of the hepatic metabolic landscape. HighlightsO_LIVagus nerve is a novel regulator of the hepatic metabolic landscape. C_LIO_LIAblation of vagus nerve neural circuit by vagotomy resulted in a metabolic shift towards glycolysis and fatty acid biosynthesis. C_LIO_LILipid accumulation was increased in vagotomized mice fed with a standard diet. C_LIO_LILiver steatosis was increased following dietary challenges with high-carbohydrate or high-fat diets. C_LIO_LIVagus nerve can be a promising new target for NAFLD treatment. C_LI

physiology↗

bioRxiv2020

The kallikrein-kinin system is falling into pieces: bradykinin fragments are biological active peptides

Background and purposeBradykinin [BK-(1-9)] is an endogenous peptide involved in many physiological and pathological processes, such as cardiovascular homeostasis and inflammation. The central dogma of the kallikrein-kinin system is that BK-(1-9) fragments are biologically inactive. In this manuscript, we proposed to test whether these fragments were indeed inactive. Experimental ApproachNitric oxide (NO) was quantified in human, mouse and rat cells loaded with DAF-FM after stimulation with BK-(1-9), BK-(1-7), BK-(1-5) and BK-(1-3). We used adult male rat aortic ring preparation to test vascular reactivity mediated by BK-(1-9) fragments. Changes in blood pressure and heart rate was measured in conscious adult male rats by intraarterial catheter method. Key resultsBK-(1-9) induced NO production in all cell types tested by B2 receptor activation. BK-(1-7), BK-(1-5) and BK-(1-3) also induced NO production in all tested cell types but this response was independent of the activation of B1 receptor and/or B2 receptor. BK-(1-7), BK-(1-5) or BK-(1-3) induced only vasorelaxant effect and in a concentration-dependent fashion. Vasorelaxant effects for BK-(1-7), BK-(1-5) or BK-(1-3) were independent of the kinin receptors. Different administration routes (i.e., intravenous or intra-arterial) did not affect the observed hypotension induced by BK-(1-7), BK-(1-5) or BK-(1-3). Importantly, these observations diverged from the BK-(1-9) results, highlighting that indeed the BK-(1-9) fragments do not seem to act via the classical kinin receptors. Conclusions and implicationsIn conclusion, BK-(1-7), BK-(1-5) and BK-(1-3) are biologically active components of the kallikrein-kinin system. Importantly, observed pathophysiological outcomes of these peptides are independent of B1R and/or B2R activation.

pharmacology and toxicology↗