Inhibition of acetylation of histones 3 and 4 attenuates aortic valve calcification

HDAC2 counteracts vascular calcification by activating autophagy in chronic kidney disease

Vascular calcification is a major risk factor for cardiovascular disease mortality, with a significant prevalence in chronic kidney disease (CKD). Pharmacological inhibition of histone acetyltransferase has been proven to protect against from vascular calcification. However, the role of Histone Deacetylase 2 (HDAC2) and molecular mechanisms in vascular calcification of CKD remains unknown. An in vivo model of CKD was established using mouse fed with a high adenine and phosphate diet, and an in vitro model was produced using human aortic vascular smooth muscle cells (VSMCs) stimulated with β-glycerophosphate (β-GP). HDAC2 expression was found to be reduced in medial artery of CKD mice and β-GP-induced VSMCs. Overexpression of HDAC2 attenuated OPN and OCN upregulation, α-SMA and SM22α downregulation, and calcium deposition in aortas of CKD. The in vitro results also demonstrated that β-GP-induced osteogenic differentiation was inhibited by HDAC2. Furthermore, we found that HDAC2 overexpression caused an increase in LC3II/I, a decrease in p62, and an induction of autophagic flux. Inhibition of autophagy using its specific inhibitor 3-MA blocked HDAC2's protective effect on osteogenic differentiation in β-GP-treated VSMCs. Taken together, these results suggest that HDAC2 may protect against vascular calcification by the activation of autophagy, laying out a novel insight for the molecular mechanism in vascular calcification of CKD.

DNA methylation and histone post-translational modifications in atherosclerosis and a novel perspective for epigenetic therapy

Atherosclerosis, which is a vascular pathology characterized by inflammation and plaque build-up within arterial vessel walls, acts as the important cause of most cardiovascular diseases. Except for a lipid-depository and chronic inflammatory, increasing evidences propose that epigenetic modifications are increasingly associated with atherosclerosis and are of interest from both therapeutic and biomarker perspectives. The chronic progressive nature of atherosclerosis has highlighted atherosclerosis heterogeneity and the fact that specific cell types in the complex milieu of the plaque are, by far, not the only initiators and drivers of atherosclerosis. Instead, the ubiquitous effects of cell type are tightly controlled and directed by the epigenetic signature, which, in turn, is affected by many proatherogenic stimuli, including low-density lipoprotein, proinflammatory, and physical forces of blood circulation. In this review, we summarize the role of DNA methylation and histone post-translational modifications in atherosclerosis. The future research directions and potential therapy for the management of atherosclerosis are also discussed. Video Abstract.

Vascular calcification: from the perspective of crosstalk

Vascular calcification (VC) is highly correlated with cardiovascular disease morbidity and mortality, but anti-VC treatment remains an area to be tackled due to the ill-defined molecular mechanisms. Regardless of the type of VC, it does not depend on a single cell but involves multi-cells/organs to form a complex cellular communication network through the vascular microenvironment to participate in the occurrence and development of VC. Therefore, focusing only on the direct effect of pathological factors on vascular smooth muscle cells (VSMCs) tends to overlook the combined effect of other cells and VSMCs, including VSMCs-VSMCs, ECs-VMSCs, Macrophages-VSMCs, etc. Extracellular vesicles (EVs) are a collective term for tiny vesicles with a membrane structure that are actively secreted by cells, and almost all cells secrete EVs. EVs docked on the surface of receptor cells can directly mediate signal transduction or transfer their contents into the cell to elicit a functional response from the receptor cells. They have been proven to participate in the VC process and have also shown attractive therapeutic prospects. Based on the advantages of EVs and the ability to be detected in body fluids, they may become a novel therapeutic agent, drug delivery vehicle, diagnostic and prognostic biomarker, and potential therapeutic target in the future. This review focuses on the new insight into VC molecular mechanisms from the perspective of crosstalk, summarizes how multi-cells/organs interactions communicate via EVs to regulate VC and the emerging potential of EVs as therapeutic methods in VC. We also summarize preclinical experiments on crosstalk-based and the current state of clinical studies on VC-related measures.

Vascular calcification in CKD: New insights into its mechanisms

Vascular calcification (VC) is a common complication of chronic kidney disease (CKD) and contributes to an increased risk of cardiovascular morbidity and mortality. However, effective therapies are still unavailable at present. It has been well established that VC associated with CKD is not a passive process of calcium phosphate deposition, but an actively regulated and cell-mediated process that shares many similarities with bone formation. Additionally, numerous studies have suggested that CKD patients have specific risk factors and contributors to the development of VC, such as hyperphosphatemia, uremic toxins, oxidative stress and inflammation. Although research efforts in the past decade have greatly improved our knowledge of the multiple factors and mechanisms involved in CKD-related VC, many questions remain unanswered. Moreover, studies from the past decade have demonstrated that epigenetic modifications abnormalities, such as DNA methylation, histone modifications and noncoding RNAs, play an important role in the regulation of VC. This review seeks to provide an overview of the pathophysiological and molecular mechanisms of VC associated with CKD, mainly focusing on the involvement of epigenetic modifications in the initiation and progression of uremic VC, with the aim to develop promising therapies for CKD-related cardiovascular events in the future.

Perspectives on pediatric congenital aortic valve stenosis: Extracellular matrix proteins, post translational modifications, and proteomic strategies

In heart valve biology, organization of the extracellular matrix structure is directly correlated to valve function. This is especially true in cases of pediatric congenital aortic valve stenosis (pCAVS), in which extracellular matrix (ECM) dysregulation is a hallmark of the disease, eventually leading to left ventricular hypertrophy and heart failure. Therapeutic strategies are limited, especially in pediatric cases in which mechanical and tissue engineered valve replacements may not be a suitable option. By identifying mechanisms of translational and post-translational dysregulation of ECM in CAVS, potential drug targets can be identified, and better bioengineered solutions can be developed. In this review, we summarize current knowledge regarding ECM proteins and their post translational modifications (PTMs) during aortic valve development and disease and contributing factors to ECM dysregulation in CAVS. Additionally, we aim to draw parallels between other fibrotic disease and contributions to ECM post-translational modifications. Finally, we explore the current treatment options in pediatrics and identify how the field of proteomics has advanced in recent years, highlighting novel characterization methods of ECM and PTMs that may be used to identify potential therapeutic strategies relevant to pCAVS.

Epigenetics: a new warrior against cardiovascular calcification, a forerunner in modern lifestyle diseases

Arterial and aortic valve calcifications are the most prevalent pathophysiological conditions among all the reported cases of cardiovascular calcifications. It increases with several risk factors like age, hypertension, external stimuli, mechanical forces, lipid deposition, malfunction of genes and signaling pathways, enhancement of naturally occurring calcium inhibitors, and many others. Modern-day lifestyle is affected by numerous environmental factors and harmful toxins that impair our health rather than providing benefits. Applying the combinatorial approach or targeting the exact mechanism could be a new strategy for drug designing or attenuating the severity of calcification. Most of the non-communicable diseases are life-threatening; thus, altering the phenotype and not the genotype may reveal the gateway for fighting with upcoming hurdles. Overall, this review summarizes the reason behind the generation of arterial and aortic valve calcification and its related signaling pathways and also the detrimental effects of calcification. In addition, the individual process of epigenetics and how the implementation of this process becomes a novel approach for diminishing the harmful effect of calcification are discussed. Noteworthy, as epigenetics is linked with genetics and environmental factors necessitates further clinical trials for complete and in-depth understanding and application of this strategy in a more specific and prudent manner.

Role of endothelial cells in vascular calcification

Vascular calcification (VC) is active and regulates extraosseous ossification progress, which is an independent predictor of cardiovascular disease (CVD) morbidity and mortality. Endothelial cells (ECs) line the innermost layer of blood vessels and directly respond to changes in flow shear stress and blood composition. Together with vascular smooth muscle cells, ECs maintain vascular homeostasis. Increased evidence shows that ECs have irreplaceable roles in VC due to their high plasticity. Endothelial progenitor cells, oxidative stress, inflammation, autocrine and paracrine functions, mechanotransduction, endothelial-to-mesenchymal transition (EndMT), and other factors prompt ECs to participate in VC. EndMT is a dedifferentiation process by which ECs lose their cell lineage and acquire other cell lineages; this progress coexists in both embryonic development and CVD. EndMT is regulated by several signaling molecules and transcription factors and ultimately mediates VC via osteogenic differentiation. The specific molecular mechanism of EndMT remains unclear. Can EndMT be reversed to treat VC? To address this and other questions, this study reviews the pathogenesis and research progress of VC, expounds the role of ECs in VC, and focuses on the regulatory factors underlying EndMT, with a view to providing new concepts for VC prevention and treatment.

Mammalian Sirtuins and Their Relevance in Vascular Calcification

Cardiovascular diseases are a group of diseases with high morbidity and mortality that affect millions of people each year. Vascular calcification (VC) is an active process that involves the mineral deposition of calcium-phosphate complexes. VC is closely related to cardiovascular diseases, such as hypertension, heart failure, and calcific aortic stenosis, and is a type of ectopic calcification that occurs in the vessel walls. The sirtuins (silent mating-type information regulation 2; SIRTs), are a family of histone deacetylases whose function relies on nicotinamide adenine dinucleotide (NAD+). They have non-negligible functions in the regulation of energy metabolism, senescence, apoptosis, and other biological processes. Sirtuins have important effects on bone homeostasis and VC processes that share many similarities with bone formation. Sirtuins have been confirmed to deacetylate a variety of target proteins related to the occurrence and development of VC, thereby affecting the process of VC and providing new possibilities for the prevention and treatment of cardiovascular diseases. To facilitate the understanding of vascular calcification and accelerate the development of cardiovascular drugs, we reviewed and summarized recent research progress on the relationship between different types of sirtuins and VC.

The Complex Interplay of Inflammation, Metabolism, Epigenetics, and Sex in Calcific Disease of the Aortic Valve

Calcification of the aortic valve is one of the most rapidly increasing pathologies in the aging population worldwide. Traditionally associated to cardiovascular risk conditions, this pathology is still relatively unaddressed on a molecular/cellular standpoint and there are no available treatments to retard its progression unless valve substitution. In this review, we will describe some of the most involved inflammatory players, the metabolic changes that may be responsible of epigenetic modifications and the gender-related differences in the onset of the disease. A better understanding of these aspects and their integration into a unique pathophysiology context is relevant to improve current therapies and patients management.

Towards Personalized Therapy of Aortic Stenosis

Calcific aortic stenosis (CAS) is the most common cause of acquired valvular heart disease in adults with no available pharmacological treatment to inhibit the disease progression to date. This review provides an up-to-date overview of current knowledge of molecular mechanisms underlying CAS pathobiology and the related treatment pathways. Particular attention is paid to current randomized trials investigating medical treatment of CAS, including strategies based on lipid-lowering and antihypertensive therapies, phosphate and calcium metabolism, and novel therapeutic targets such as valvular oxidative stress, coagulation proteins, matrix metalloproteinases, and accumulation of advanced glycation end products.

Acetyltransferase p300 Is a Putative Epidrug Target for Amelioration of Cellular Aging-Related Cardiovascular Disease

Cardiovascular disease is the leading cause of accelerated as well as chronological aging-related human morbidity and mortality worldwide. Genetic, immunologic, unhealthy lifestyles including daily consumption of high-carb/high-fat fast food, lack of exercise, drug addiction, cigarette smoke, alcoholism, and exposure to environmental pollutants like particulate matter (PM)-induced stresses contribute profoundly to accelerated and chronological cardiovascular aging and associated life threatening diseases. All these stressors alter gene expression epigenetically either through activation or repression of gene transcription via alteration of chromatin remodeling enzymes and chromatin landscape by DNA methylation or histone methylation or histone acetylation. Acetyltransferase p300, a major epigenetic writer of acetylation on histones and transcription factors, contributes significantly to modifications of chromatin landscape of genes involved in cellular aging and cardiovascular diseases. In this review, the key findings those implicate acetyltransferase p300 as a major contributor to cellular senescence or aging related cardiovascular pathologies including vascular dysfunction, cardiac hypertrophy, myocardial infarction, cardiac fibrosis, systolic/diastolic dysfunction, and aortic valve calcification are discussed. The efficacy of natural or synthetic small molecule inhibitor targeting acetyltransferase p300 in amelioration of stress-induced dysregulated gene expression, cellular aging, and cardiovascular disease in preclinical study is also discussed.

Telocytes-derived extracellular vesicles alleviate aortic valve calcification by carrying miR-30b

AIMS

Calcific aortic valve disease (CAVD) is frequent in the elderly. Telocytes (TCs) are implicated in intercellular communication by releasing extracellular vesicles (EVs). This study investigated the role of TC-EVs in aortic valve calcification.

METHODS AND RESULTS

TCs were obtained and identified using enzymolysis method and flow cytometry. EVs were isolated from TCs using differential high-speed centrifugation method and identified using transmission electron microscope, western blot, and qNano analysis. The mouse model of CAVD was established. The changes of aortic valve activity-related indicators were analysed by ultrasound, and the expressions of TC markers CD34 and vimentin in mouse valve tissues were detected using RT-qPCR and western blot. The model mice were injected with TC-derived EVs. The expressions of Runx2, osteocalcin, and caspase-3 were detected using RT-qPCR and western blot. The calcification model of valvular interstitial cells (VICs) was established. TC-EVs were co-cultured with calcified VICs, and calcium deposition was detected using alizarin red S staining. miR-30b expression in calcified valvular tissues and cells was detected after EV treatment. miR-30b expression in TCs was knocked down and then EVs were extracted and co-cultured with calcified VICs. The target of miR-30b was predicted through bioinformatics website and verified using dual-luciferase assay. The levels of Wnt/β-catenin pathway-related proteins were detected. ApoE^-/- mice fed with a high-fat diet showed decreased aortic valve orifice area, increased aortic transvalvular pressure difference and velocity, reduced left ventricular ejection fraction, decreased CD34 and vimentin, and increased caspase-3, Runx2, and osteocalcin. The levels of apoptosis- and osteogenesis- related proteins were inhibited after EV treatment. TC-EVs reduced calcium deposition and osteogenic proteins in calcified VICs. EVs could be absorbed by VICs. miR-30b expression was promoted in calcified valvular tissues and cells after EV treatment. Knockdown of miR-30b weakened the inhibitory effects of TC-EVs on calcium deposition and osteogenic proteins. miR-30b targeted Runx2. EV treatment inhibited the Wnt/β-catenin pathway, and knockdown of miR-30b in TCs attenuated the inhibitory effect of TC-EVs on the Wnt/β-catenin pathway.

CONCLUSION

TC-EVs played a protective role in aortic valve calcification via the miR-30b/Runx2/Wnt/β-catenin axis.

Piperlongumine Attenuates High Calcium/Phosphate-Induced Arterial Calcification by Preserving P53/PTEN Signaling

Vascular calcification frequently occurs in the process of chronic kidney disease, atherosclerosis and aging, resulting in an increased prevalence of cardiovascular events. Piperlongumine (PLG) is a natural product isolated from Piper longum L. Here, we aimed to explore the effect of PLG in high calcium- and phosphate-induced vascular calcification and the associated mechanism. Flow cytometry assays showed that PLG at concentrations <10 μM did not promote vascular smooth muscle cells (VSMCs) apoptosis, and PLG at concentrations >2.5 μM inhibited VSMCs proliferation. Thus, 2.5 μM PLG was selected for subsequent experiments. Alizarin red staining and ALP activity assays showed that PLG inhibited calcium deposition of VSMCs treated with high calcium/phosphate medium. PLG also decreased the expression of osteogenic genes and proteins, including Runx2, Bmp2, and OPN, as determined by qRT-PCR and western blotting. In a vitamin D-induced aortic calcification mouse model, a 5 mg/kg dose of PLG decreased calcium deposition in the aortic wall as well as Runx2 expression. With regard to the mechanism, we found that the levels of P53 mRNA and protein in both VSMCs and mouse aortic tissues were decreased in the calcification models, and we observed that PLG preserved the levels of P53 and its downstream gene PTEN. Concurrent treatment of VSMCs with P53 ShRNA and PLG blunted the anti-calcific effect of PLG. In conclusion, PLG attenuates high calcium/phosphate-induced vascular calcification by upregulating P53/PTEN signaling in VSMCs. PLG may act as a promising herbal extract for the clinical management of vascular calcification.

Piperlongumine attenuates angiotensin-II-induced cardiac hypertrophy and fibrosis by inhibiting Akt-FoxO1 signalling

BACKGROUND

Cardiac hypertrophy and fibrosis are closely related to cardiac dysfunction, especially diastolic dysfunction. Limited medications can be used to simultaneously delay cardiac hypertrophy and fibrosis in clinical practice. Piperlongumine (PLG) is an amide alkaloid extracted from Piper longum and has been shown to have multiple biological effects, including anticancer and antioxidant effects. However, the role of PLG in cardiac hypertrophy and fibrosis is not clear.

PURPOSE

The aim of this study was to reveal the role of PLG in cardiac hypertrophy and fibrosis and the associated mechanism.

METHODS

Cardiac hypertrophy and fibrosis were induced by angiotensin II (Ang II) in vivo and in vitro. The effect of PLG in vivo, in vitro and its mechanism were investigated by proliferation and apoptosis assays, western blot, real-time PCR, immunofluorescence, histochemistry, echocardiography, flow cytometry and chromatin immunoprecipitation.

RESULTS

Proliferation and apoptosis assays showed that 2.5 μM PLG slightly inhibited proliferation and did not promote apoptosis. Treatment with 5 mg/kg PLG obviously inhibited Ang II-induced cardiac hypertrophy and fibrosis in vivo. In vitro studies of neonatal rat cardiomyocytes (NRCMs) showed that the anti-hypertrophic effect of PLG was mediated by reducing the phosphorylation of Akt and thereby preserving the level of Forkhead box transcription factor O1 (FoxO1), since knockdown of FoxO1 by siRNA reversed the protective effect of PLG on NRCMs. In addition, PLG significantly decreased the Ang II-induced expression of profibrotic proteins in neonatal cardiac fibroblasts by reducing the expression of Krüppel-like factor 4 (KLF4) and the recruitment of KLF4 to the promoter regions of transforming growth factor-β and connective tissue growth factor.

CONCLUSION

We demonstrate the cardioprotective effects of PLG in both cardiac hypertrophy and fibrosis and the potential value of PLG for developing novel medications for pathological cardiac hypertrophy and heart failure.

Upregulated microRNA‑330‑3p promotes calcification in the bicuspid aortic valve via targeting CREBBP

One key risk factor of aortic valve stenosis in clinical practice is bicuspid aortic valve (BAV). Increasing evidence indicates that numerous microRNAs (miRs/miRNAs) are involved in BAV calcification via their target genes. miR-330-3p was found to be involved in the deterioration of BAV calcification by miR profiling in human calcified BAV and tricuspid aortic valve (TAV) tissues in the present study and the underlying mechanism was investigated. RNA sequencing was performed on four BAV and four TAV tissues from patients with aortic stenosis before these leaflets were examined for the expression levels of miR-330-3p and CREB-binding protein (CREBBP) by reverse transcription-PCR. The alteration of functional factors associated with calcification was also assessed by Western blotting and immunohistochemistry in human aortic tissue samples. The putative target of miR-330-3p was detected by dual-luciferase assay in 293 cells. Furthermore, the influence of miR-330-3p expression on osteogenic progression was explored in cultured porcine valve interstitial cells (VICs). Rescue experiments of CRBBP were performed to confirm the influence of the miR-330-3p-CREBBP pathway in the calcification progress in porcine VICs. RNA sequencing indicated distinct expression of miR-330-3p in human BAV tissues compared with TAV, which was then confirmed by PCR. CREBBP expression levels in human BAV and TAV leaflets also demonstrated the opposite alterations. This negative correlation was then confirmed in cultured porcine VICs. Under an osteogenic environment, cellular calcification was promoted in miR-330-3p-overexpressed porcine VICs expressing higher bone morphogenetic protein 2, Runt-related transcription factor 2, matrix metalloproteinase (MMP)-2, MMP-9 and collagen I compared with controls. Rescue experiments further confirmed that miR-330-3p played its role via targeting CREBBP in porcine VICs. Collectively, miR-330-3p was upregulated in calcified BAV compared with TAV. The upregulation of miR-330-3p promotes the calcification progress partially via targeting CREBBP.

Roles of Histone Acetylation Modifiers and Other Epigenetic Regulators in Vascular Calcification

Vascular calcification (VC) is characterized by calcium deposition inside arteries and is closely associated with the morbidity and mortality of atherosclerosis, chronic kidney disease, diabetes, and other cardiovascular diseases (CVDs). VC is now widely known to be an active process occurring in vascular smooth muscle cells (VSMCs) involving multiple mechanisms and factors. These mechanisms share features with the process of bone formation, since the phenotype switching from the contractile to the osteochondrogenic phenotype also occurs in VSMCs during VC. In addition, VC can be regulated by epigenetic factors, including DNA methylation, histone modification, and noncoding RNAs. Although VC is commonly observed in patients with chronic kidney disease and CVD, specific drugs for VC have not been developed. Thus, discovering novel therapeutic targets may be necessary. In this review, we summarize the current experimental evidence regarding the role of epigenetic regulators including histone deacetylases and propose the therapeutic implication of these regulators in the treatment of VC.