Biology subjects

Guatimosim, S.

Publications and source records attributed to Guatimosim, S..

3 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↗

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↗

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↗