Biology subjects

Valerio, V.

Publications and source records attributed to Valerio, V..

3 recordsLinked to original sources

bioRxiv2025

Sirtuin 1 modulation unlocks the therapeutic potential of sodium-glucose co-transporter 2 inhibitors (SGLT2i) in calcific aortic valve stenosis

BackgroundCalcific aortic valve stenosis (AS) affects 3% of older adults and lacks medical treatment. The deacetylase Sirtuin 1 (SIRT1) could be involved in many pathways linked to AS progression. Sodium-glucose co-transporter 2 inhibitors (SGLT2i), glucose-lowering agents, have been shown to reduce cardiovascular events (likely via SIRT1), but their possible benefits in AS are unknown. Our study aims to uncover the role of SIRT1 in AS progression and assess the benefit of SGLT2i to slow down the aortic valve fibro-calcification processes. MethodsRNA-seq data of human aortic valve specimens were collected from ARChS4 database. SIRT1 knockdown (SIRT1 KD) and overexpressing (SIRT1 Over) valve interstitial cells (VIC) were generated by CRISPR/Cas9. Real-time PCR, immunofluorescence, and calcification assays were used to characterized mutant VICs. Conditioned medium experiments were implemented to evaluate SGLT2i effect on cellular cross-talk and calcification. Diabetic patients data from the Lombardy regional healthcare database, treated with sulphonylureas (SU; no effect on SIRT1) and SGLT2i (acting on SIRT1), were selected and matched 1:1 by age, sex, and multisource comorbidity score. Cumulative incidence of hospitalization for non-rheumatic aortic valve disease was assessed by Kaplan-Meier and multivariable Cox proportional hazards models were used to estimate hazard ratios. ResultsRNA-seq showed that SIRT1 could be a master regulator of multiple AS-related pathways. Functional studies on mutant VICs revealed that SIRT1 directly regulates antioxidant processes, extracellular-matrix remodeling and calcification by modulating key transcription factors. Moreover, calcification assays further support this role, revealing an increased calcification in SIRT1 KD VICs and a concomitant decrease in VIC SIRT1 Over when compared to wild type. Then, exploring SGLT2i impact on calcification, we showed that VICs cultured in SGLT2i-treated-endothelial medium exhibited reduced calcification associated with endothelial-increased nitric oxide levels, while SIRT1 inhibition enhanced VIC calcification. The real-world data analysis revealed that SGLT2i-treated group had a lower incidence of hospitalized patients for non-rheumatic aortic valve disease compared to SU-treated group. ConclusionsOur data identify SIRT1 as a key regulator of fibro-calcific processes in AS and suggest that SGLT2i may slow the aortic valve degeneration through SIRT1 modulation. These findings highlight SGLT2i as a promising therapeutic option for AS prevention and care. Clinical PerspectivesO_ST_ABSWhat is new?C_ST_ABSO_LISirtuin 1 (SIRT1) downregulation is linked to the progression of aortic stenosis (AS) pathological processes and plays a crucial role in mitigating oxidative stress, fibrosis, and calcification. C_LIO_LISodium-glucose co-transporter 2 inhibitor (SGLT2i) treatment of valve endothelial cells results in the secretion of protective factors that reduce valve interstitial cell calcification, highlighting the valuable role of endothelial health in preventing valve degeneration. C_LIO_LIReal-world data indicate that the use of SGLT2i is associated with a lower incidence of hospitalization rate for aortic valve disease as compared to sulfonylureas, suggesting a protective effect against AS in diabetic patients. C_LI What are the clinical implications?O_LIThis study highlights the potential of restoring SIRT1 activity as a therapeutic strategy to mitigate pro-calcific and pro-fibrotic processes in AS. C_LIO_LISGLT2i may offer a breakthrough therapeutic option for AS, a condition currently lacking effective pharmacological treatments, providing new hope for slowing disease progression and improving clinical outcomes. C_LI

cell biology↗

bioRxiv2024

Immortalization of human valve interstitial cells: an in vitro tool for studying fibro-calcific aortic valve degeneration

Human primary valve interstitial cells (VIC) are essential for studying the detrimental fibrocalcification processes typical of aortic valve degeneration. However, their limited lifespan poses a significant challenge. To address this, we immortalized VICs to extend their lifespan and facilitate genetic manipulation, enabling the study of dysregulated molecular and cellular pathways in this pathology and the test of potential drugs in vitro. We achieved immortalization by transducing primary VICs with simian virus 40 gene and human telomerase large T gene. Post-immortalization, we conducted RNA sequencing on both primary and immortalized VICs to identify pathways regulation following infection. Additionally, we assessed whether immortalized VICs retained their mesenchymal markers and responded to the pro-osteogenic and pro-calcific stimuli similarly to primary VICs. Given the comparable data obtained from both cell types, we propose using immortalized VICs as a reliable tool for in vitro study of fibro-calcific aortic valve degeneration.

cell biology↗

bioRxiv2019

Genetic inhibition of PCSK9, atherogenic lipoprotein concentrations, and calcific aortic valve stenosis

BackgroundProprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition reduces plasma concentrations of low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (apoB) and lipoprotein(a) [Lp(a)]. Atherogenic lipoprotein levels have been linked with calcific aortic valve stenosis (CAVS). Our objectives were to determine the association between variants in PCSK9 and lipoprotein-lipid levels, coronary artery disease (CAD) and CAVS, and to evaluate if PCSK9 could be implicated in aortic valve interstitial cells (VICs) calcification. MethodsWe built a genetic risk score weight for LDL-C levels (wGRS) using 10 independent PCSK9 single nucleotide polymorphisms and determined its association with lipoprotein-lipid levels in 9692 participants of the EPIC-Norfolk study. We investigated the association between the wGRS and CAD and CAVS in the UK Biobank, as well as the association between the PCSK9 R46L variant and CAVS in a meta-analysis of published prospective, population-based studies (Copenhagen studies, 1463 cases/101,620 controls) and unpublished studies (UK Biobank, 1350 cases/349,043 controls, Malmo Diet and Cancer study, 682 cases/5963 controls and EPIC-Norfolk study, 508 cases/20,421 controls). We evaluated PCSK9 expression and localization in explanted aortic valves by capillary Western blot and immunohistochemistry in patients with and without CAVS. Von Kossa staining was used to visualize aortic leaflet calcium deposits. PCSK9 expression under oxidative stress conditions in VICs was assessed. ResultsThe wGRS was significantly associated with lower LDL-C and apoB (p<0.001), but not with Lp(a). In the UK Biobank, the association of PCSK9 variants with CAD were positively correlated with their effects on apoB levels. CAVS was less prevalent in carriers of the PCSK9 R46L variant [odds ratio=0.71 (95% confidence interval, 0.57-0.88), p<0.001]. PCSK9 expression was elevated in the aortic valves of patients with aortic sclerosis and CAVS compared to controls. In calcified leaflets, PCSK9 co-localized with calcium deposits. PCSK9 expression was induced by oxidative stress in VICs. ConclusionGenetic inhibition of PCSK9 is associated with lifelong reductions in the levels of non-Lp(a) apoB-containing lipoproteins as well as lower odds of CAD and CAVS. PCSK9 is abundant in fibrotic and calcified aortic leaflets. Oxidative stress increases PCSK9 expression in VICs. These results provide a rationale for performing randomized clinical trials of PCSK9 inhibition in CAVS.

genetics↗