Leader: Tommaso Angelone (UNICAL); Other collaborator(s):
Within this task murine and human cell models of cardiac aging will be employed for testing novel cardioprotective therapies and individuate early biomarker of cardiovascular aging. This will allow to investigate the effects of combination therapy directed to multiple molecular targets aiming to booster the endogenous antioxidant capacity, target both cardiomyocyte and non-cardiomyocyte components (endothelial cells and fibroblasts), and act with a combined pharmacological action (novel antioxidants, such as selenoproteins, and anti-inflammatory agents). Finally, a proof-of-concept clinical study for testing canonical and novel biomarkers of aging predisposing to cardiovascular diseases will be set up.
Brief description of the activities and of the intermediate results
Maladaptive cardiac hypertrophy contributes to the development of heart failure (HF). The oxidoreductase Selenoprotein T (SELENOT) emerged as a key regulator during rat cardiogenesis and acute cardiac protection. However, its action in chronic settings of cardiac dysfunction is not understood. We investigated the role of SELENOT in the pathophysiology of HF: i) by designing a small peptide (PSELT), recapitulating SELENOT activity via the redox site, and assessed its beneficial action in a preclinical model of HF [aged spontaneously hypertensive heart failure (SHHF) rats] and against isoproterenol (ISO)-induced hypertrophy in rat ventricular H9c2 and adult human AC16 cardiomyocytes; ii) by evaluating the SELENOT intra-cardiomyocyte production and secretion under hypertrophied stimulation. Results showed that PSELT attenuated systemic inflammation, LPS-induced macrophage M1 polarization, myocardial injury, and severe ultrastructural alterations, while counteracting key mediators of cardiac fibrosis and aging, and restoring desmin downregulation and SELENOT upregulation in the failing hearts. In the hemodynamic assessment, PSELT improved the contractile impairment at baseline and following ischemia/reperfusion injury, and reduced infarct size in normal and failing hearts. At cellular level, PSELT counteracted ISO-mediated hypertrophy and ultrastructural alterations through its redox motif, while mitigating ISO-triggered SELENOT intracellular production and secretion, a phenomenon that presumably reflects the extent of cell damage. Our findings indicate that SELENOT could represent a novel sensor of hypertrophied cardiomyocytes and a potential PSELT-based new therapeutic approach in myocardial hypertrophy and HF.
Selected contribution in Age-It General Meeting (20-21 May 2024, Venice):
Molecular analyses were conducted on human AC16 cardiomyocytes exposed to low doses of doxorubicin (DOX) to induce a senescent phenotype and treated with PSELT and/or NLRP3 inflammasome inhibitors. These analyses aimed to assess the expression levels of senescence hallmarks (i.e., p53 and p21) and markers of mitochondrial dysfunction caused by imbalances in fusion/fission processes (i.e., OPA1 and DRP1). Additionally, the expression levels of SELENOT and NLRP3 were evaluated to elucidate their pathophysiological role in the context of senescence. A paper entitled: "Elucidating emerging signaling pathways driving endothelial dysfunction in cardiovascular aging" was drafted, addressing the latest evidence on the emerging molecular events underlying cardiac and vascular dysfunction during ageing. The aim is to provide insights into the therapeutic potential of targeting novel molecular determinants to develop strategies capable of controlling and reducing cardiovascular risk in the elderly population.
Molecular analyses were conducted to assess the potential protective action of the selenoprotein T (SELENOT)-derived mimetic peptide, PSELT, in mitigating endoplasmic reticulum stress (ERS) and DNA damage in senescent human cardiomyocytes. These analyses focused on evaluating the expression levels of specific molecular markers of ERS (i.e BiP, IRE1α, ERO1α, and Calnexin) and indicators of DNA damage (e.g., Lamin B1 and p-γH2AX). In the context of doxorubicin (Dox)-induced senescence, the role of PSELT as a post-conditioning agent was further examined by analyzing molecular markers of the senescent phenotype. To gain deeper insights into the potential protective effect of PSELT in the context of cardiac senescence and aging, alternative cellular senescence models, beyond doxorubicin, were established. These included exposure to D-galactose for 48 hours and an assessment of PSELT’s impact on distinct molecular traits of cellular senescence. Additionally, in vivo experimental protocols were started on a physiologically ageing mouse model (C57BL/6J at 22-24 months of age) to explore the role of the endogenous protein SELENOT in the intracellular mechanisms underlying cardiovascular ageing.
Scientific papers:
Abstract to national/international conferences:
2024