DUSP26 induces aortic valve calcification by antagonizing MDM2-mediated ubiquitination of DPP4 in human valvular interstitial cells

The N6-methyladenosine demethylase ALKBH5 is a novel epigenetic regulator of aortic valve calcification

AIMS

Calcific aortic valve disease (CAVD) is a common heart valve disease with significant clinical consequences. The mechanisms that drive the pathogenesis of CAVD remain to be fully elucidated. N6-methyladenosine (m6A), the most prevalent RNA epigenetic regulator, has recently been implicated in cardiovascular disease, but its role in CAVD has yet to be investigated. In this study, we investigated the potential function of m6A modification in CAVD.

METHODS AND RESULTS

Using clinical samples from CAVD patients in combination with human valve interstitial cell (hVIC) calcification model, we screened the expression of m6A modulators and discovered that alkB homolog 5, RNA demethylase (ALKBH5), a key m6A demethylase, was significantly down-regulated in calcified hVICs and human aortic valves. Consistently, increased m6A levels were seen in calcified hVICs, and treatment with 3-deazaadenosine (DAA), an inhibitor of m6A modification, significantly reduced hVIC osteogenic differentiation and calcification. In addition, we showed that silencing of ALKBH5 expression increased global m6A levels and accelerated hVIC osteogenic differentiation and calcification, whereas overexpression of ALKBH5 resulted in the opposite effect. We demonstrated that ALKBH5 directly modulate m6A levels of TGFBR2 and its mRNA stability, leading to altered TGFBR2 expression and SMAD2 signalling in hVICs. We further showed that inhibition of TGFBR2 or knockdown of SMAD2 attenuated ALKBH5 knockdown-induced hVIC osteogenic differentiation and calcification. The expression of the m6A reader protein YTH N6-methyladenosine RNA binding protein F1 (YTHDF1) was up-regulated during the process of hVIC calcification. Intriguingly, we revealed that the ALKBH5 silencing-induced increased hVIC osteogenic differentiation and calcification were abolished after knockdown of YTHDF1. These data suggest a potential role YTHDF1 in aortic valve calcification.

CONCLUSION

This study showed that ALKBH5 attenuated aortic valve calcification through the TGFBR2/SMAD2 signalling pathway via direct m6A modification of TGFBR2.

Identification and Experimental Validation of NETosis-Mediated Abdominal Aortic Aneurysm Gene Signature Using Multi-omics, Machine Learning, and Mendelian Randomization

Abdominal aortic aneurysm (AAA) is a life-threatening disorder with limited therapeutic options. Neutrophil extracellular traps (NETs) are formed by a process known as "NETosis" that has been implicated in AAA pathogenesis, yet the roles and prognostic significance of NET-related genes in AAA remain poorly understood. This study aimed to identify key AAA- and NET-related genes (AAA-NETs-RGs), elucidate their potential mechanisms in contributing to AAA, and explore potential therapeutic compounds for AAA therapy. Through bioinformatics analysis of multiomics and machine learning, we identified six AAA-NETs-RGs: DUSP26, FCN1, MTHFD2, GPRC5C, SEMA4A, and CCR7, which exhibited strong diagnostic potential for predicting AAA progression, were significantly enriched in pathways related to cytokine-cytokine receptor interaction and chemokine signaling. Immune infiltration analysis revealed a causal association between AAA-NETs-RGs and immune cell infiltration. Cell-cell communication analysis indicated that AAA-NETs-RGs predominantly function in smooth muscle cells, B cells, T cells, and NK cells, primarily through cytokine and chemokine signaling. Gene profiling revealed that CCR7 and MTHFD2 exhibited the most significant upregulation in AAA patients compared to non-AAA controls, as well as in in vitro AAA models. Notably, genetic depletion of CCR7 and MTHFD2 strongly inhibited Ang II-induced phenotypic switching, functional impairment, and senescence in vascular smooth muscle cells (VSMCs). Based on AAA-NETs-RGs, molecular docking analysis combined with the Connectivity Map (CMap) database identified mirdametinib as a potential therapeutic agent for AAA. Mirdametinib effectively alleviated Ang II-induced phenotypic switching, biological dysfunction, and senescence. These findings provide valuable insights into understanding the pathophysiology of AAA and highlight promising therapeutic strategies targeting AAA-NETs-RGs.

Thrombospondin-1 Silencing Ameliorates Osteoblastic Differentiation of Aortic Valve Interstitial Cells via Inhibiting Nuclear Factor-κB Pathway

Objective: Calcific aortic valve disease (CAVD) is a progressive cardiovascular condition driven by the osteogenic differentiation of valve interstitial cells (VICs), with no effective drug therapies currently available. Hence, our objective is to investigate the impact of thrombospondin-1 (TSP-1) silencing on CAVD progression. Methods: In vitro experiments were employed using human primary VICs with TSP-1 knockdown, cultured in osteogenic induction medium, and followed by analyses including western blot, alkaline phosphatase staining, alizarin red staining, immunofluorescence, and flow cytometry. In vivo experiments used two murine models of CAVD to determine the role of TSP-1 silencing on aortic valve calcification. Results: We observed that silencing of TSP-1 reduced the osteogenic differentiation of VICs. Subsequent experiments demonstrated that TSP-1 knockdown suppressed nuclear factor-κB (NF-κB)-mediated inflammation during osteoblastic differentiation of VICs. Consistent findings were also observed in two murine models of CAVD. Conclusions: The present study has shown that TSP-1 silencing could mitigate the development of CAVD by inhibiting NF-κB-mediated inflammation. We propose that targeting TSP-1-mediated NF-κB pathway could provide a potential therapeutic method for treating CAVD.

Regulatory roles of PIWI-interacting RNAs in cardiovascular disease

Cardiovascular disease remains the number one cause of death worldwide. Across the spectrum of cardiovascular pathologies, all are accompanied by changes in gene expression profiles spanning a variety of cellular components of the myocardium. Alterations in gene expression are regulated by small noncoding RNAs (sncRNAs), with P-element-induced WImpy testis (PIWI)-interacting RNAs (piRNAs) being the most abundant of the sncRNAs in the human genome. Composed of 21-35 nucleotides in length with a protective methyl group at the 3' end, piRNAs complex with highly conserved RNA-binding proteins termed PIWI proteins to recruit enzymes used for histone, DNA, RNA, and protein modifications. Thus, specific piRNA expression patterns can be exploited for early clinical diagnosis of cardiovascular disease and the development of novel RNA therapeutics that may improve cardiac health outcomes. This review summarizes the latest progress made on understanding how piRNAs regulate cardiovascular health and disease progression, including a discussion of their potential in the development of biomarkers and therapeutics.

Navigating the Landscape of Translational Medicine of Calcific Aortic Valve Disease: Bridging Bench to Bedside

Calcific aortic valve disease (CAVD) is a prevalent condition characterized by pathological thickening and calcification of the aortic valve, leading to increased pressure overload and cardiac remodeling, particularly in individuals aged 65 and older. This review synthesizes recent advances in understanding the pathogenesis of CAVD, focusing on key mechanisms including hemodynamic alterations, endothelial dysfunction, lipid deposition, inflammation, and fibrotic calcification. We evaluate emerging therapeutic targets based on pivotal basic research and clinical trials, highlighting the potential for mechanism-oriented interventions. Furthermore, we explore the implications of lipid-lowering therapies, anti-inflammatory strategies, and antifibrocalcific agents, as well as novel bioprosthetic designs aimed at enhancing patient outcomes. Additionally, we discuss the inherent genetic and molecular backgrounds influencing individual susceptibility to CAVD, emphasizing the promise of personalized therapy. By bridging the gap between basic science and clinical application, this review aims to guide future research efforts toward more effective prevention and treatment strategies for CAVD.

Mib2 Regulates Lipid Metabolism in Heart Failure With Preserved Ejection Fraction via the Runx2-Hmgcs2 Axis

Obesity and the mismanagement of lipids significantly contribute to the development of heart failure with preserved ejection fraction (HFpEF). However, the underlying molecular mechanisms that regulate the metabolic changes and disruptions in lipid balance within HFpEF remain to be fully understood. Transcriptome data for HFpEF were sourced from the National Center for Biotechnology Information (NCBI) database. A mouse model for HFpEF was developed utilising leptin-deficient (ob/ob) mice. The cardiac-specific mind bomb E3 ubiquitin protein ligase 2 (Mib2) overexpression in ob/ob mice was achieved by tail vein injection of a recombinant adeno-associated virus serotype 9 vector carrying Mib2 with a cTNT promoter (AAV9-cTNT-Mib2). In vitro, neonatal rat ventricular myocytes were exposed to fatty acid to induce lipotoxicity. The molecular mechanisms were investigated through proteomic analysis, dual luciferase reporter gene assay, and immunoprecipitation assays. GO and KEGG enrichment analyses indicated that the differentially expressed proteins (DEPs) in HFpEF were prominently enriched in pathways related to the fatty acid metabolic process. The transcriptomic and proteomic analyses of heart tissues from HFpEF mice presented a notable elevation in the expression of 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2). Immunoprecipitation assays revealed that mind bomb 2 (Mib2) directly interacted with runt-related transcription factor 2 (Runx2), ubiquitinating and degrading Runx2 to inhibit Hmgcs2 transcription, impeding the fatty acid metabolic process. Mice with cardiac-specific overexpression of Mib2 displayed a more pronounced progression of cardiac dysfunction and an accumulation of lipids compared to the control group. Our research uncovers a mechanism by which Mib2 modulates cardiac lipid metabolic homeostasis in HFpEF, implicating the Runx2-Hmgcs2 axis.

Establishment and characterization of a novel immortalized human aortic valve interstitial cell line

Primary human aortic valvular interstitial cells (pHAVICs) play crucial roles in maintaining the mechanical structure and microenvironmental homeostasis of aortic valves. Pathologic processes such as inflammation, senescence, apoptosis, and metabolic disorders of valvular interstitial cells often lead to calcified aortic valve disease (CAVD). However, the lack of clinically relevant cellular models has impeded our understanding of CAVD. Here, we immortalized primary HAVICs with SV40 LTA. The iHAVICs (immortalized human aortic valvular interstitial cells) were maintained in a nonsenescent state and still had the potential to be induced into a senescent phenotype. In calcification induction experiments, iHAVICs can be induced to transform into osteogenic phenotypes via different stimuli via different pathways, accompanied by variations in different markers. In conclusion, we established and characterized a novel human immortalized aortic valve interstitial cell line as a practical in vitro experimental tool for the study of aortic valve calcification disease.

MARCH5 ameliorates aortic valve calcification via RACGAP1-DRP1 associated mitochondrial quality control

BACKGROUND

Mitochondrial E3 ubiquitin ligase (MARCH5) as an important regulator in maintaining mitochondrial function. Our aims were to investigate the role and mechanism of MARCH5 in aortic valve calcification.

METHODS

Human aortic valves, both calcified and non-calcified, were analyzed for MARCH5 expression using western blotting. Mitochondrial fragmentation was evaluated using transmission electron microscope. Osteogenic differentiation of human aortic valvular interstitial cells (HVICs) was induced with osteoblastic medium (OM), confirmed by western blotting and Alizarin red staining. Mitochondrial morphology and oxidative phosphorylation were assessed using MitoTracker and Seahorse, respectively. MARCH5-knockdown and ApoE-knockout mice fed high-fat diet were used to study aortic valve calcification.

RESULTS

The mitochondrial quality control was impaired in calcified valves, and the level of MARCH5 protein was also decreased in calcified valves. Inhibition of MARCH5 impaired mitochondrial quality control, increased mitochondrial stress and accelerates osteogenic transformation in OM treated HVICs. While, overexpression MARCH5 has the opposite effects. Co-immunoprecipitation, mass spectrometry and molecular docking found MARCH5 interacted Rac GTPase-activating protein 1 (RACGAP1) and promoted its ubiquitination, leading to impaired mitochondrial quality control. Inhibiting RACGAP1 reversed osteogenic transformation induced by MARCH5 silencing in OM treated HVICs. Silencing dynamin-related protein 1 (DRP1) under RACGAP1 inhibition had no additional benefit. In vivo, deficiency of MARCH5 promoted aortic valve calcification, while inhibition RACGAP1 reversed aortic valve calcification in MARCH5 deficiency mice.

CONCLUSION

Downregulation of MARCH5 promotes RACGAP1 ubiquitination, activating DRP1 and impairing mitochondrial quality control, which contributes to aortic valve calcification. This identifies a potential therapeutic target for aortic valve calcification.

Insights into the Molecular Mechanisms of Bushen Huoxue Decoction in Breast Cancer via Network Pharmacology and in vitro experiments

AIMS

Breast cancer (BC) is by far seen as the most common malignancy globally, with 2.261 million patients newly diagnosed, accounting for 11.7% of all cancer patients, according to the Global Cancer Statistics Report (2020). The luminal A subtype accounts for at least half of all BC diagnoses. According to TCM theory, Bushen Huoxue Decoction (BSHXD) is a prescription used for cancer treatment that may influence luminal A subtype breast cancer (LASBC).

OBJECTIVES

To analyze the clinical efficacy and underlying mechanisms of BSHXD in LASBC.

MATERIALS AND METHODS

Network pharmacology and in vitro experiments were utilized to foresee the underlying mechanism of BSHXD for LASBC.

RESULTS

According to the bioinformatics analysis, BSHXD induced several proliferation and apoptosis processes against LASBC, and the presumed targets of active components in BSHXD were mainly enriched in the HIF-1 and PI3K/AKT pathways. Flow cytometry assay and western blotting results revealed that the rate of apoptosis enhanced in a dose-dependent manner with BSHXD concentration increasing, respectively. BSHXD notably downregulated the expressions of HIF-1α, P-PI3K, PI3K, P-AKT and AKT proteins. However, adding an HIF-1α agonist restored those protein levels.

CONCLUSION

The study proved that the mechanism of BSHXD in LASBC may be connected to suppressing proliferation by inhibiting the activity of the HIF-1α/PI3K/AKT signaling pathway and promoting apoptosis via the Caspase cascade in LASBC cells.

Unprecedented nor-seco-diterpene lactones inhibited osteogenic differentiation of valve interstitial cells

The first examples of ent-atisane and ent-isopimarane diterpene lactones with an unusual 2,3-seco-2-nor-tetrahydro-2H-pyran-2-one nucleus, eufislactones A (1) and B (2), were isolated from the roots of Euphorbia fischeriana, together with a new (3) and fifteen known biosynthetic congeners (4-18). Their structures incorporating absolute configurations were elucidated via the comprehensive spectroscopic analyses, electronic circular dichroism (ECD) calculation, and single-crystal X-ray diffraction analyses. Biogenetically, compounds 1 and 2 were constructed by the plausible monomeric precursors, ent-atis-16-ene-3,14-dione (6) and ent-isopimara-8(14),15-dien-3-one (17), respectively, via key Baeyer-Villiger oxidation, decarboxylation, and semi-acetalization reactions to create a unique 2,3-seco-2-nor-tetrahydro-2H-pyran-2-one core. Our bioassays have revealed that eufislactone A (EFA, 1) displayed significant inhibitory effect on the osteogenic differentiation of human valvular interstitial cells (VICs), highlighting its potential as a preventive agent against the progression of human calcific aortic valve disease (CAVD).

Targeting DUSP26 to drive cardiac mitochondrial dynamics via FAK-ERK signaling in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a severe cardiac complication of diabetes mellitus, characterized by structural and functional myocardial abnormalities. The molecular mechanisms underlying DCM, particularly the role of dual-specificity phosphatase 26 (DUSP26), remain insufficiently understood. Our study reveals that DUSP26 expression is markedly downregulated in the cardiomyocytes of diabetic db/db mice and under glucolipotoxic stress. Overexpression of DUSP26 in db/db mice significantly improved cardiac function, as demonstrated by enhanced left ventricular ejection fraction and fractional shortening, alongside reduced myocardial fibrosis and hypertrophy. Mitochondrial analysis indicated that DUSP26 overexpression led to increased ATP production, enhanced mitochondrial fusion, and improved structural integrity. In addition, lipid accumulation was reduced, reflecting enhanced metabolic function. We also discovered that DUSP26 is necessary for regulating the focal adhesion kinase (FAK)-extracellular signal-regulated kinase (ERK) pathway, with pharmacological activation of FAK partially offsetting the benefits of DUSP26 overexpression in rescue experiments. These findings underscore the pivotal role of DUSP26 as a potential therapeutic target, highlighting the importance of developing targeted molecular interventions to address diabetic cardiac complications.

DPP-IV as a potential candidate in anti-obesity and obesity-related diseases treatment

Along with social development and lifestyle changes, the number of overweight and obese patients worldwide is rising annually. Obesity is a chronic metabolic disease with complex etiology. Dipeptidyl peptidase IV (DPP-IV) is a novel adipokine with significantly elevated expression in the visceral fat of obese patients. DPP-IV is a molecule that regulates metabolic homeostasis and inflammatory processes. Through its enzymatic activity, it plays a significant part in achieving hypoglycemic and weight loss effects through various pathways. DPP-IV and DPP-IV inhibitors also have pleiotropic effects in modulating obesity-related diseases by reducing obesity-related inflammation, ameliorating inflammatory bowel disease (IBD), improving hepatic steatosis and lowering cardiovascular risk, and even decreasing the risk of novel coronavirus disease-19 (COVID-19). This paper reviews the mechanisms of action based on DPP-IV targets in obesity and metabolic homeostasis, as well as their active role in the treatment of chronic diseases associated with obesity.

Lumican promotes calcific aortic valve disease through H3 histone lactylation

BACKGROUND AND AIMS

Valve interstitial cells (VICs) undergo a transition to intermediate state cells before ultimately transforming into the osteogenic cell population, which is a pivotal cellular process in calcific aortic valve disease (CAVD). Herein, this study successfully delineated the stages of VIC osteogenic transformation and elucidated a novel key regulatory role of lumican (LUM) in this process.

METHODS

Single-cell RNA-sequencing (scRNA-seq) from nine human aortic valves was used to characterize the pathological switch process and identify key regulatory factors. The in vitro, ex vivo, in vivo, and double knockout mice were constructed to further unravel the calcification-promoting effect of LUM. Moreover, the multi-omic approaches were employed to analyse the molecular mechanism of LUM in CAVD.

RESULTS

ScRNA-seq successfully delineated the process of VIC pathological transformation and highlighted the significance of LUM as a novel molecule in this process. The pro-calcification role of LUM is confirmed on the in vitro, ex vivo, in vivo level, and ApoE-/-//LUM-/- double knockout mice. The LUM induces osteogenesis in VICs via activation of inflammatory pathways and augmentation of cellular glycolysis, resulting in the accumulation of lactate. Subsequent investigation has unveiled a novel LUM driving histone modification, lactylation, which plays a role in facilitating valve calcification. More importantly, this study has identified two specific sites of histone lactylation, namely, H3K14la and H3K9la, which have been found to facilitate the process of calcification. The confirmation of these modification sites' association with the expression of calcific genes Runx2 and BMP2 has been achieved through ChIP-PCR analysis.

CONCLUSIONS

The study presents novel findings, being the first to establish the involvement of lumican in mediating H3 histone lactylation, thus facilitating the development of aortic valve calcification. Consequently, lumican would be a promising therapeutic target for intervention in the treatment of CAVD.

Unmet needs and knowledge gaps in aortic stenosis: A position paper from the Heart Valve Council of the French Society of Cardiology

Nowadays, valvular heart disease remains a significant challenge among cardiovascular diseases, affecting millions of people worldwide and exerting substantial pressure on healthcare systems. Within the spectrum of valvular heart disease, aortic stenosis is the most common valvular lesion in developed countries. Despite notable advances in understanding its pathophysiological processes, improved cardiovascular imaging techniques and expanding therapeutic options in recent years, there are still unmet needs and knowledge gaps regarding aortic stenosis pathophysiology, severity assessment, management and decision-making strategy. This review, prepared on behalf of the Heart Valve Council of the French Society of Cardiology, describes these gaps and future research perspectives to improve the outcome of patients with aortic stenosis.

Cellular and molecular biology of posttranslational modifications in cardiovascular disease

Cardiovascular disease (CVD) has now become the leading cause of death worldwide, and its high morbidity and mortality rates pose a great threat to society. Although numerous studies have reported the pathophysiology of CVD, the exact pathogenesis of all types of CVD is not fully understood. Therefore, much more research is still needed to explore the pathogenesis of CVD. With the development of proteomics, many studies have successfully identified the role of posttranslational modifications in the pathogenesis of CVD, including key processes such as apoptosis, cell metabolism, and oxidative stress. In this review, we summarize the progress in the understanding of posttranslational modifications in cardiovascular diseases, including novel protein posttranslational modifications such as succinylation and nitrosylation. Furthermore, we summarize the currently identified histone deacetylase (HDAC) inhibitors used to treat CVD, providing new perspectives on CVD treatment modalities. We critically analyze the roles of posttranslational modifications in the pathogenesis of CVD-related diseases and explore future research directions related to posttranslational modifications in cardiovascular diseases.

Overexpression of DUSP26 gene suppressed the proliferation, migration, and invasion of human prostate cancer cells

Prostate cancer (PCa) is threatening the health of millions of people, the pathological mechanism of prostate cancer has not been fully elaborated, and needs to be further explored. Here, we found that the expression of DUSP26 is dramatically suppressed, and a positive connection of its expression with PCa prognosis was also observed. In vitro, overexpression of DUSP26 significantly inhibited the proliferative, migrative, and invasive capacities of PC3 cells, DUSP26 silencing presented opposite results. Tumor formation experiments in subcutaneous nude mice demonstrated that DUSP26 overexpression could significantly suppress PC3 growth in vivo. Moreover, the mechanism of DUSP26 gene and PCa was discovered by RNA-Seq analysis. We found that DUSP26 significantly inhibited MAPK signaling pathway activation, and further experiments displayed that DUSP26 could impair TAK1, p38, and JNK phosphorylation. Interestingly, treatment with the TAK1 inhibitor (iTAK1) attenuated the effect of DUSP26 on PC3 cells. Together, these results suggested that DUSP26 may serve as a novel therapeutic target for PC3 cell type PCa, the underlying mechanism may be through TAK1-JNK/p38 signaling.

Nesfatin-1 mitigates calcific aortic valve disease via suppressing ferroptosis mediated by GSH/GPX4 and ZIP8/SOD2 axes

OBJECTIVE

Calcific aortic valve disease (CAVD) predominantly affects the elderly and currently lacks effective medical treatments. Nesfatin-1, a peptide derived from the cleavage of Nucleobindin 2, has been implicated in various calcification processes, both physiological and pathological. This study explores the impact of Nesfatin-1 on the transformation of aortic valve interstitial cells (AVICs) in CAVD.

METHODS AND RESULTS

In vitro experiments showed that Nesfatin-1 treatment mitigated the osteogenic differentiation of AVICs. Corresponding in vivo studies demonstrated a deceleration in the progression of CAVD. RNA-sequencing of AVICs treated with and without Nesfatin-1 highlighted an enrichment of the Ferroptosis pathway among the top pathways identified by the Kyoto Encyclopedia of Genes and Genomes analysis. Further examination confirmed increased ferroptosis in both calcified valves and osteoblast-like AVICs, with a reduction in ferroptosis following Nesfatin-1 treatment. Within the Ferroptosis pathway, ZIP8 showed the most notable modulation by Nesfatin-1. Silencing ZIP8 in AVICs increased ferroptosis and osteogenic differentiation, decreased intracellular Mn2+ concentration, and reduced the expression and activity of superoxide dismutase (SOD2). Furthermore, the silencing of SOD2 exacerbated ferroptosis and osteogenic differentiation. Nesfatin-1 treatment was found to elevate the expression of glutathione peroxidase 4 (GPX4) and levels of glutathione (GSH), as confirmed by Western blotting and GSH concentration assays.

CONCLUSION

In summary, Nesfatin-1 effectively inhibits the osteogenic differentiation of AVICs by attenuating ferroptosis, primarily through the GSH/GPX4 and ZIP8/SOD2 pathways.

Schisandrol B inhibits calcification of aortic valve by targeting p53 related inflammatory and senescence

Calcific aortic valve disease (CAVD) primarily involves osteogenic differentiation in human aortic valve interstitial cells (hVICs). Schisandrol B (SolB), a natural bioactive constituent, has known therapeutic effects on inflammatory and fibrotic disorders. However, its impact on valve calcification has not been reported. We investigated the effect of SolB on osteogenic differentiation of hVICs. Transcriptome sequencing was used to analyze potential molecular pathways affected by SolB treatment. The study also included an in vivo murine model using aortic valve wire injury surgery to observe SolB's effect on valve calcification. SolB inhibited the osteogenic differentiation of hVICs, reversing the increase in calcified nodule formation and osteogenic proteins. In the murine model, SolB significantly decreased the peak velocity of the aortic valve post-injury and reduced valve fibrosis and calcification. Transcriptome sequencing identified the p53 signaling pathway as a key molecular target of SolB, demonstrating its role as a molecular glue in the mouse double minute 2 (MDM2)-p53 interaction, thereby promoting p53 ubiquitination and degradation, which further inhibited p53-related inflammatory and senescence response. These results highlighted therapeutic potential of SolB for CAVD via inhibiting p53 signaling pathway and revealed a new molecular mechanism of SolB which provided a new insight of theraputic mechanism for CAVD.

Ex vivo model of pathological calcification of human aortic valve

The development of drug therapy for the pathological calcification of the aortic valve is still an open issue due to the lack of effective treatment strategies. Currently, the only option for treating this condition is surgical correction and symptom management. The search for models to study the safety and efficacy of anti-calcifying drugs requires them to not only be as close as possible to in vivo conditions, but also to be flexible with regard to the molecular studies that can be applied to them. The ex vivo model has several advantages, including the ability to study the effect of a drug on human cells while preserving the original structure of the valve. This allows for a better understanding of how different cell types interact within the valve, including non-dividing cells. The aim of this study was to develop a reproducible ex vivo calcification model based on valves from patients with calcific aortic stenosis. We aimed to induce spontaneous calcification in valve tissue fragments under osteogenic conditions, and to demonstrate the possibility of significantly suppressing it using a calcification inhibitor. To validate the model, we tested a Notch inhibitor Crenigacestat (LY3039478), which has been previously shown to have an anti-calcifying effect on interstitial cell of the aortic valve. We demonstrate here an approach to testing calcification inhibitors using an ex vivo model of cultured human aortic valve tissue fragments. Thus, we propose that ex vivo models may warrant further investigation for their utility in studying aortic valve disease and performing pre-clinical assessment of drug efficacy.

Post-translational modifications in kidney diseases and associated cardiovascular risk

Patients with chronic kidney disease (CKD) are at an increased cardiovascular risk compared with the general population, which is driven, at least in part, by mechanisms that are uniquely associated with kidney disease. In CKD, increased levels of oxidative stress and uraemic retention solutes, including urea and advanced glycation end products, enhance non-enzymatic post-translational modification events, such as protein oxidation, glycation, carbamylation and guanidinylation. Alterations in enzymatic post-translational modifications such as glycosylation, ubiquitination, acetylation and methylation are also detected in CKD. Post-translational modifications can alter the structure and function of proteins and lipoprotein particles, thereby affecting cellular processes. In CKD, evidence suggests that post-translationally modified proteins can contribute to inflammation, oxidative stress and fibrosis, and induce vascular damage or prothrombotic effects, which might contribute to CKD progression and/or increase cardiovascular risk in patients with CKD. Consequently, post-translational protein modifications prevalent in CKD might be useful as diagnostic biomarkers and indicators of disease activity that could be used to guide and evaluate therapeutic interventions, in addition to providing potential novel therapeutic targets.

FOXO1 regulates RUNX2 ubiquitination through SMURF2 in calcific aortic valve disease

The prevalence of calcific aortic valve disease (CAVD) remains substantial while there is currently no medical therapy available. Forkhead box O1 (FOXO1) is known to be involved in the pathogenesis of cardiovascular diseases, including vascular calcification and atherosclerosis; however, its specific role in calcific aortic valve disease remains to be elucidated. In this study, we identified FOXO1 significantly down-regulated in the aortic valve interstitial cells (VICs) of calcified aortic valves by investigating clinical specimens and GEO database analysis. FOXO1 silencing or inhibition promoted VICs osteogenic differentiation in vitro and aortic valve calcification in Apoe-/- mice, respectively. We identified that FOXO1 facilitated the ubiquitination and degradation of RUNX2, which process was mainly mediated by SMAD-specific E3 ubiquitin ligase 2 (SMURF2). Our discoveries unveil a heretofore unacknowledged mechanism involving the FOXO1/SMURF2/RUNX2 axis in CAVD, thereby proposing the potential therapeutic utility of FOXO1 or SMURF2 as viable strategies to impede the progression of CAVD.

Noncoding RNA regulates the expression of Krm1 and Dkk2 to synergistically affect aortic valve lesions

Calcific aortic valve disease (CAVD) is becoming an increasingly important global medical problem, but effective pharmacological treatments are lacking. Noncoding RNAs play a pivotal role in the progression of cardiovascular diseases, but their relationship with CAVD remains unclear. Sequencing data revealed differential expression of many noncoding RNAs in normal and calcified aortic valves, with significant differences in circHIPK3 and miR-182-5p expression. Overexpression of circHIPK3 ameliorated aortic valve lesions in a CAVD mouse model. In vitro experiments demonstrated that circHIPK3 inhibits the osteogenic response of aortic valve interstitial cells. Mechanistically, DEAD-box helicase 5 (DDX5) recruits methyltransferase 3 (METTL3) to promote the N6-methyladenosine (m6A) modification of circHIPK3. Furthermore, m6A-modified circHIPK3 increases the stability of Kremen1 (Krm1) mRNA, and Krm1 is a negative regulator of the Wnt/β-catenin pathway. Additionally, miR-182-5p suppresses the expression of Dickkopf2 (Dkk2), the ligand of Krm1, and attenuates the Krm1-mediated inhibition of Wnt signaling. Activation of the Wnt signaling pathway significantly contributes to the promotion of aortic valve calcification. Our study describes the role of the Krm1-Dkk2 axis in inhibiting Wnt signaling in aortic valves and suggests that noncoding RNAs are upstream regulators of this process.

miR-548ag promotes DPP4 expression in hepatocytes through activation of TLR(7/8)/NF-κB pathway

OBJECTIVE

In our previous study, we identified a notable increase in miR-548ag content after obesity, which contributes to the progression of Type 2 diabetes Mellitus(T2DM) through the up-regulation of Dipeptidyl Peptidase-4(DPP4) expression within the liver. However, the precise molecular mechanisms underlying the upregulation of DPP4 by miR-548ag remain elusive. Mature miRNAs rich in GU sequences can activate the TLR(7/8)/NF-κB signalling pathway, which transcriptionally activates DPP4 expression. Notably, the proportion of GU sequences in hsa-miR-548ag was found to be 47.6%. The study proposes a hypothesis suggesting that miR-548ag could potentially increase DPP4 expression in hepatocytes by activating the TLR(7/8)/NF-κB signalling pathway.

METHODS

Male C57BL/6J mice were fed normal chow diet (NCD, n = 16) or high-fat diet (HFD, n = 16) for 12 weeks. For a duration of 6 weeks, NCD mice received intraperitoneal injections of a miR-548ag mimic, while HFD mice and db/db mice (n = 16) were administered intraperitoneal injections of a miR-548ag inhibitor. qRT-PCR and Western Blot were used to detect the expression level of miR-548ag, DPP4 and the activation of TLR(7/8)/NF-κB signalling pathway. HepG2 and L02 cells were transfected with miR-548ag mimic, miR-548ag inhibitor, TLR7/8 interfering fragment, and overexpression of miR-548ag while inhibiting TLR7/8, respectively.

RESULTS

(1) We observed elevated levels of miR-548ag in the serum, adipose tissue, and liver of obese mice, accompanied by an upregulation of TLR7/8, pivotal protein in the NF-κB pathway, and DPP4 expression in the liver. (2) miR-548ag promotes DPP4 expression in hepatocytes via the TLR(7/8)/NF-κB signalling pathway, resulting in a reduction in the glucose consumption capacity of hepatocytes. (3) The administration of a miR-548ag inhibitor enhanced glucose tolerance and insulin sensitivity in db/db mice.

CONCLUSIONS

MiR-548ag promotes the expression of DPP4 in hepatocytes by activating the TLR(7/8)/NF-κB signalling pathway. MiR-548ag may be a potential target for the treatment of T2DM.

AVCAPIR: A Novel Procalcific PIWI-Interacting RNA in Calcific Aortic Valve Disease

BACKGROUND

Calcification of the aortic valve leads to increased leaflet stiffness and consequently results in the development of calcific aortic valve disease (CAVD). However, the underlying molecular and cellular mechanisms of calcification remain unclear. Here, we identified a novel aortic valve calcification-associated PIWI-interacting RNA (piRNA; AVCAPIR) that increases valvular calcification and promotes CAVD progression.

METHODS

Using piRNA sequencing, we identified piRNAs contributing to the pathogenesis of CAVD that we termed AVCAPIRs. High-cholesterol diet-fed ApoE-/- mice with AVCAPIR knockout were used to examine the role of AVCAPIR in aortic valve calcification (AVC). Gain- and loss-of-function assays were conducted to determine the role of AVCAPIR in the induced osteogenic differentiation of human valvular interstitial cells. To dissect the mechanisms underlying AVCAPIR-elicited procalcific effects, we performed various analyses, including an RNA pulldown assay followed by liquid chromatography-tandem mass spectrometry, methylated RNA immunoprecipitation sequencing, and RNA sequencing. RNA pulldown and RNA immunoprecipitation assays were used to study piRNA interactions with proteins.

RESULTS

We found that AVCAPIR was significantly upregulated during AVC and exhibited potential diagnostic value for CAVD. AVCAPIR deletion markedly ameliorated AVC in high-cholesterol diet-fed ApoE-/- mice, as shown by reduced thickness and calcium deposition in the aortic valve leaflets, improved echocardiographic parameters (decreased peak transvalvular jet velocity and mean transvalvular pressure gradient, as well as increased aortic valve area), and diminished levels of osteogenic markers (Runx2 and Osterix) in aortic valves. These results were confirmed in osteogenic medium-induced human valvular interstitial cells. Using unbiased protein-RNA screening and molecular validation, we found that AVCAPIR directly interacts with FTO (fat mass and obesity-associated protein), subsequently blocking its N6-methyladenosine demethylase activity. Further transcriptomic and N6-methyladenosine modification epitranscriptomic screening followed by molecular validation confirmed that AVCAPIR hindered FTO-mediated demethylation of CD36 mRNA transcripts, thus enhancing CD36 mRNA stability through the N6-methyladenosine reader IGF2BP1 (insulin-like growth factor 2 mRNA binding protein 1). In turn, the AVCAPIR-dependent increase in CD36 stabilizes its binding partner PCSK9 (proprotein convertase subtilisin/kexin type 9), a procalcific gene, at the protein level, which accelerates the progression of AVC.

CONCLUSIONS

We identified a novel piRNA that induced AVC through an RNA epigenetic mechanism and provide novel insights into piRNA-directed theranostics in CAVD.

SIRT6-mediated Runx2 downregulation inhibits osteogenic differentiation of human aortic valve interstitial cells in calcific aortic valve disease

Calcific aortic valve disease (CAVD) is a progressive cardiovascular disorder involving multiple pathogenesis. Effective pharmacological therapies are currently unavailable. Sirtuin6 (SIRT6) has been shown to protect against aortic valve calcification in CAVD. The exact regulatory mechanism of SIRT6 in osteoblastic differentiation remains to be determined, although it inhibits osteogenic differentiation of aortic valve interstitial cells. We demonstrated that SIRT6 was markedly downregulated in calcific human aortic valves. Mechanistically, SIRT6 suppressed osteogenic differentiation in human aortic valve interstitial cells (HAVICs), as confirmed by loss- and gain-of-function experiments. SIRT6 directly interacted with Runx2, decreased Runx2 acetylation levels, and facilitated Runx2 nuclear export to inhibit the osteoblastic phenotype transition of HAVICs. In addition, the AKT signaling pathway acted upstream of SIRT6. Together, these findings elucidate that SIRT6-mediated Runx2 downregulation inhibits aortic valve calcification and provide novel insights into therapeutic strategies for CAVD.

Models for calcific aortic valve disease in vivo and in vitro

Calcific Aortic Valve Disease (CAVD) is prevalent among the elderly as the most common valvular heart disease. Currently, no pharmaceutical interventions can effectively reverse or prevent CAVD, making valve replacement the primary therapeutic recourse. Extensive research spanning decades has contributed to the establishment of animal and in vitro cell models, which facilitates a deeper understanding of the pathophysiological progression and underlying mechanisms of CAVD. In this review, we provide a comprehensive summary and analysis of the strengths and limitations associated with commonly employed models for the study of valve calcification. We specifically emphasize the advancements in three-dimensional culture technologies, which replicate the structural complexity of the valve. Furthermore, we delve into prospective recommendations for advancing in vivo and in vitro model studies of CAVD.

(Pro)renin receptor mediates tubular epithelial cell pyroptosis in diabetic kidney disease via DPP4-JNK pathway

BACKGROUND

(Pro)renin receptor (PRR) is highly expressed in renal tubules, which is involved in physiological and pathological processes. However, the role of PRR, expressed in renal tubular epithelial cells, in diabetic kidney disease (DKD) remain largely unknown.

METHODS

In this study, kidney biopsies, urine samples, and public RNA-seq data from DKD patients were used to assess PRR expression and cell pyroptosis in tubular epithelial cells. The regulation of tubular epithelial cell pyroptosis by PRR was investigated by in situ renal injection of adeno-associated virus9 (AAV9)-shRNA into db/db mice, and knockdown or overexpression of PRR in HK-2 cells. To reveal the underlined mechanism, the interaction of PRR with potential binding proteins was explored by using BioGrid database. Furthermore, the direct binding of PRR to dipeptidyl peptidase 4 (DPP4), a pleiotropic serine peptidase which increases blood glucose by degrading incretins under diabetic conditions, was confirmed by co-immunoprecipitation assay and immunostaining.

RESULTS

Higher expression of PRR was found in renal tubules and positively correlated with kidney injuries of DKD patients, in parallel with tubular epithelial cells pyroptosis. Knockdown of PRR in kidneys significantly blunted db/db mice to kidney injury by alleviating renal tubular epithelial cells pyroptosis and the resultant interstitial inflammation. Moreover, silencing of PRR blocked high glucose-induced HK-2 pyroptosis, whereas overexpression of PRR enhanced pyroptotic cell death of HK-2 cells. Mechanistically, PRR selectively bound to cysteine-enrich region of C-terminal of DPP4 and augmented the protein abundance of DPP4, leading to the downstream activation of JNK signaling and suppression of SIRT3 signaling and FGFR1 signaling, and then subsequently mediated pyroptotic cell death.

CONCLUSIONS

This study identified the significant role of PRR in the pathogenesis of DKD; specifically, PRR promoted tubular epithelial cell pyroptosis via DPP4 mediated signaling, highlighting that PRR could be a promising therapeutic target in DKD.

Herpud1 deficiency alleviates homocysteine-induced aortic valve calcification

OBJECTIVES

To evaluate the role and therapeutic value of homocysteine (hcy)-inducible endoplasmic reticulum stress (ERS) protein with ubiquitin like domain 1 (Herpud1) in hcy-induced calcific aortic valve disease (CAVD).

BACKGROUND

The morbidity and mortality rates of calcific aortic valve disease (CAVD) remain high while treatment options are limited.

METHODS

In vivo, we use the low-density lipoprotein receptor (LDLR) and Herpud1 double knockout (LDLR-/-/Herpud1-/-) mice and used high methionine diet (HMD) to assess of aortic valve calcification lesions, ERS activation, autophagy, and osteogenic differentiation of aortic valve interstitial cells (AVICs). In vitro, the role of Herpud1 in the Hcy-related osteogenic differentiation of AVICs was investigated by manipulating of Herpud1 expression.

RESULTS

Herpud1 was highly expressed in calcified human and mouse aortic valves as well as primary aortic valve interstitial cells (AVICs). Hcy increased Herpud1 expression through the ERS pathway and promoted CAVD progression. Herpud1 deficiency inhibited hcy-induced CAVD in vitro and in vivo. Herpud1 silencing activated cell autophagy, which subsequently inhibited hcy-induced osteogenic differentiation of AVICs. ERS inhibitor 4-phenyl butyric acid (4-PBA) significantly attenuated aortic valve calcification in HMD-fed low-density lipoprotein receptor-/- (LDLR-/-) mice by suppressing ERS and subsequent Herpud1 biosynthesis.

CONCLUSIONS

These findings identify a previously unknown mechanism of Herpud1 upregulation in Hcy-related CAVD, suggesting that Herpud1 silencing or inhibition is a viable therapeutic strategy for arresting CAVD progression.

HIGHLIGHTS

• Herpud1 is upregulated in the leaflets of Hcy-treated mice and patients with CAVD. • In mice, global knockout of Herpud1 alleviates aortic valve calcification and Herpud1 silencing activates cell autophagy, inhibiting osteogenic differentiation of AVICs induced by Hcy. • 4-PBA suppressed Herpud1 expression to alleviate AVIC calcification in Hcy treated AVICs and to mitigate aortic valve calcification in mice.

Tumor-associated macrophage-derived exosomes LINC01592 induce the immune escape of esophageal cancer by decreasing MHC-I surface expression

BACKGROUND

TAMs (tumor-associated macrophages) infiltration promotes the progression of esophageal cancer (EC). However, the underlying mechanisms remain unclear.

METHODS

Abnormal expression of LINC01592 from EC microarrays of the TCGA database was analyzed. LINC01592 expression level was validated in both EC cell lines and tissues. Stable LINC01592 knockdown and overexpression of EC cell lines were established. In vitro and in vivo trials were conducted to test the impact of LINC01592 knockdown and overexpression on EC cells. RNA binding protein immunoprecipitation (RIP), RNA pulldown assays, and Immunofluorescence (IF) were used to verify the combination of E2F6 and LINC01592. The combination of E2F6 and NBR1 was verified through the utilization of ChIP and dual luciferase reporter assays.

RESULTS

LINC01592 is carried and transferred by exosomes secreted by M2-TAMs to tumor cells. The molecular mechanism underlying the promotion of NBR1 transcription involves the direct binding of LINC01592 to E2F6, which facilitates the nuclear entry of E2F6. The collaborative action of LINC01592 and E2F6 results in improved NBR1 transcription. The elevation of NBR1 binding to the ubiquitinated protein MHC-I via the ubiquitin domain caused a higher degradation of MHC-I in autophagolysosomes and a reduction in MHC-I expression on the exterior of cancerous cell. Consequently, this caused cancerous cells to escape from CD8+ CTL immune attack. The tumor-promoting impacts of LINC01592, as well as the growth of M2-type macrophage-driven tumors, were significantly suppressed by the interruption of E2F6/NBR1/MHC-I signaling through the effect of siRNA or the corresponding antibody blockade. Significantly, the suppression of LINC01592 resulted in an upregulation of MHC-I expression on the tumor cell membrane, thereby enhancing the efficacy of CD8+ T cell reinfusion therapy.

CONCLUSIONS

The investigation conducted has revealed a significant molecular interaction between TAMs and EC via the LINC01592/E2F6/NBR1/MHC-I axis, which facilitates the progression of malignant tumors. This suggests that a therapeutic intervention targeting this axis may hold promise for the treatment of the disease.

Human antigen R regulates autophagic flux by stabilizing autophagy-associated mRNA in calcific aortic valve disease

AIMS

The incidence of calcific aortic valve disease (CAVD) has risen over the last decade and is expected to continue rising; however, pharmacological approaches have proven ineffective. In this study, we evaluated the role and underlying mechanisms of human antigen R (HuR)-mediated post-transcriptional regulation in CAVD.

METHODS AND RESULTS

We found that HuR was significantly upregulated in human calcified aortic valves and primary aortic valvular interstitial cells (VICs) following osteogenic stimulation. Subsequent functional studies revealed that HuR silencing ameliorated calcification both in vitro and in vivo. For the first time, we demonstrated that HuR directly interacted with the transcript of phosphatidylinositol-5-phosphate 4-kinase, type II, alpha (PIP4K2A), which mediates phosphatidylinositol signalling, facilitates autophagy, and acts as an mRNA stabilizer. HuR positively modulated PIP4K2A expression at the post-transcriptional level and consequently influenced the AKT/mTOR/ATG13 pathway to regulate autophagy and CAVD progression.

CONCLUSION

Our study provides new insights into the post-transcriptional regulatory role of HuR in modulating autophagy-positive factors to regulate the pathogenesis of CAVD. Our findings highlight the potential of HuR as an innovative therapeutic target in CAVD treatment.

Sam68 promotes osteogenic differentiation of aortic valvular interstitial cells by TNF-α/STAT3/autophagy axis

Calcified aortic valve disease (CAVD) is a major non-rheumatic heart valve disease in the world, with a high mortality rate and without suitable pharmaceutical therapy due to its complex mechanisms. Src-associated in mitosis 68-KD (Sam68), an RNA binding protein, has been reported as a signaling adaptor in numerous signaling pathways (Huot in Mol Cell Biol, 29(7), 1933-1943, 2009), particularly in inflammatory signaling pathways. The effects of Sam68 on the osteogenic differentiation process of hVICs and its regulation on signal transducer and activator of transcription 3 (STAT3) signaling pathway have been investigated in this study. Human aortic valve samples detection found that Sam68 expression was up-regulated in human calcific aortic valves. We used tumor necrosis factor α (TNF-α) as an activator for osteogenic differentiation in vitro and the result indicated that Sam68 was highly expressed after TNF-α stimulation. Overexpression of Sam68 promoted osteogenic differentiation of hVICs while Sam68 knockdown reversed this effect. Sam68 interaction with STAT3 was predicted by using String database and was verified in this study. Sam68 knockdown reduced phosphorylation of STAT3 activated by TNF-α and the downstream gene expression, which further influenced autophagy flux in hVICs. STAT3 knockdown alleviated the osteogenic differentiation and calcium deposition promoted by Sam68 overexpression. In conclusion, Sam68 interacts with STAT3 and participates in its phosphorylation to promote osteogenic differentiation of hVICs to induce valve calcification. Thus, Sam68 may be a new therapeutic target for CAVD. Regulatory of Sam68 in TNF-α/STAT3/Autophagy Axis in promoting osteogenesis of hVICs.

Targeted inhibition of PTPN22 is a novel approach to alleviate osteogenic responses in aortic valve interstitial cells and aortic valve lesions in mice

BACKGROUND

Calcific aortic valve disease (CAVD) is the most prevalent valvular disease and has high morbidity and mortality. CAVD is characterized by complex pathophysiological processes, including inflammation-induced osteoblastic differentiation in aortic valve interstitial cells (AVICs). Novel anti-CAVD agents are urgently needed. Protein tyrosine phosphatase nonreceptor type 22 (PTPN22), an intracellular nonreceptor-like protein tyrosine phosphatase, is involved in several chronic inflammatory diseases, including rheumatoid arthritis and diabetes. However, it is unclear whether PTPN22 is involved in the pathogenesis of CAVD.

METHODS

We obtained the aortic valve tissue from human and cultured AVICs from aortic valve. We established CAVD mice model by wire injury. Transcriptome sequencing, western bolt, qPCR, and immunofluorescence were performed to elucidate the molecular mechanisms.

RESULTS

Here, we determined that PTPN22 expression was upregulated in calcific aortic valve tissue, AVICs treated with osteogenic medium, and a mouse model of CAVD. In vitro, overexpression of PTPN22 induced osteogenic responses, whereas siRNA-mediated PTPN22 knockdown abolished osteogenic responses and mitochondrial stress in the presence of osteogenic medium. In vivo, PTPN22 ablation ameliorated aortic valve lesions in a wire injury-induced CAVD mouse model, validating the pathogenic role of PTPN22 in CAVD. Additionally, we discovered a novel compound, 13-hydroxypiericidin A 10-O-α-D-glucose (1 → 6)-β-D-glucoside (S18), in a marine-derived Streptomyces strain that bound to PTPN22 with high affinity and acted as a novel inhibitor. Incubation with S18 suppressed osteogenic responses and mitochondrial stress in human AVICs induced by osteogenic medium. In mice with aortic valve injury, S18 administration markedly alleviated aortic valve lesions.

CONCLUSION

PTPN22 plays an essential role in the progression of CAVD, and inhibition of PTPN22 with S18 is a novel option for the further development of potent anti-CAVD drugs. Therapeutic inhibition of PTPN22 retards aortic valve calcification through modulating mitochondrial dysfunction in AVICs.

The Emerging Role of Protein Phosphatase in Regeneration

Maintaining normal cellular behavior is essential for the survival of organisms. One of the main mechanisms to control cellular behavior is protein phosphorylation. The process of protein phosphorylation is reversible under the regulation of protein kinases and protein phosphatases. The importance of kinases in numerous cellular processes has been well recognized. In recent years, protein phosphatases have also been demonstrated to function actively and specifically in various cellular processes and thus have gained more and more attention from researchers. In the animal kingdom, regeneration frequently occurs to replace or repair damaged or missing tissues. Emerging evidence has revealed that protein phosphatases are crucial for organ regeneration. In this review, after providing a brief overview of the classification of protein phosphatases and their functions in several representative developmental processes, we highlight the critical roles that protein phosphatases play in organ regeneration by summarizing the most recent research on the function and underlying mechanism of protein phosphatase in the regeneration of the liver, bone, neuron, and heart in vertebrates.

Rho A/ROCK1 signaling-mediated metabolic reprogramming of valvular interstitial cells toward Warburg effect accelerates aortic valve calcification via AMPK/RUNX2 axis

The aberrant differentiation of valvular interstitial cells (VICs) to osteogenic lineages promotes calcified aortic valves disease (CAVD), partly activated by potentially destructive hemodynamic forces. These involve Rho A/ROCK1 signaling, a mechano-sensing pathway. However, how Rho A/ROCK1 signaling transduces mechanical signals into cellular responses and disrupts normal VIC homeostasis remain unclear. We examined Rho A/ROCK1 signaling in human aortic valves, and further detected how Rho A/ROCK1 signaling regulates mineralization in human VICs. Aortic valves (CAVD n = 22, normal control (NC) n = 12) from patients undergoing valve replacement were investigated. Immunostaining and western blotting analysis indicated that Rho A/ROCK1 signaling, as well as key transporters and enzymes involved in the Warburg effect, were markedly upregulated in human calcified aortic valves compared with those in the controls. In vitro, Rho A/ROCK1-induced calcification was confirmed as AMPK-dependent, via a mechanism involving metabolic reprogramming of human VICs to Warburg effect. Y-27632, a selective ROCK1 inhibitor, suppressed the Warburg effect, rescued AMPK activity and subsequently increased RUNX2 ubiquitin-proteasome degradation, leading to decreased RUNX2 protein accumulation in human VICs under pathological osteogenic stimulus. Rho A/ROCK1 signaling, which is elevated in human calcified aortic valves, plays a positive role in valvular calcification, partially through its ability to drive metabolic switching of VICs to the Warburg effect, leading to altered AMPK activity and RUNX2 protein accumulation. Thus, Rho A/ROCK1 signaling could be an important and unrecognized hub of destructive hemodynamics and cellular aerobic glycolysis that is essential to promote the CAVD process.

Hepatic Glucose Metabolism Disorder Induced by Adipose Tissue-Derived miR-548ag via DPP4 Upregulation

The present study aimed to explore the molecular mechanism underlying the regulation of glucose metabolism by miR-548ag. For the first time, we found that miR-548ag expression was elevated in the abdominal adipose tissue and serum of subjects with obesity and type 2 diabetes mellitus (T2DM). The conditional knockout of adipose tissue Dicer notably reduced the expression and content of miR-548ag in mouse adipose tissue, serum, and liver tissue. The combined use of RNAseq, an miRNA target gene prediction software, and the dual luciferase reporter assay confirmed that miR-548ag exerts a targeted regulatory effect on DNMT3B and DPP4. miR-548ag and DPP4 expression was increased in the adipose tissue, serum, and liver tissue of diet-induced obese mice, while DNMT3B expression was decreased. It was subsequently confirmed both in vitro and in vivo that adipose tissue-derived miR-548ag impaired glucose tolerance and insulin sensitivity by inhibiting DNMT3B and upregulating DPP4. Moreover, miR-548ag inhibitors significantly improved the adverse metabolic phenotype in both obese mice and db/db mice. These results revealed that the expression of the adipose tissue-derived miR-548ag increased in obese subjects, and that this could upregulate the expression of DPP4 by targeting DNMT3B, ultimately leading to glucose metabolism disorder. Therefore, miR-548ag could be utilized as a potential target in the treatment of T2DM.

Gene signature and prognostic value of ubiquitination-related genes in endometrial cancer

Protein ubiquitination is closely related to tumor occurrence and development. The specific role of ubiquitination in endometrial cancer remains largely unclear. Therefore, we constructed a novel endometrial cancer prognostic model based on ubiquitination-related genes. We extracted the expression matrices of ubiquitination-related genes from the Cancer Genome Atlas database, upon which we performed univariate Cox regression and least absolute shrinkage and selection operator (LASSO) regression analyses to obtain 22 ubiquitination-related genes for the construction of the prognostic model. Survival, regression, clinical correlation, and principal component analyses were performed to assess the performance of the model. Drug sensitivity analysis was performed based on these ubiquitination-related genes. Finally, a prognostic nomogram was constructed based on the prognostic model to quantify patient outcomes. Survival, regression, clinical correlation, and principal component analyses revealed that the performance of the prognostic model was satisfactory. Drug sensitivity analysis provided a potential direction for the treatment of endometrial cancer. The prognostic nomogram could be used to effectively estimate the survival rate of patients with endometrial cancer. In summary, we constructed a new endometrial cancer prognostic model and identified 5 differentially expressed, prognosis-associated, ubiquitination-related genes. These 5 genes are potential diagnostic and treatment targets for endometrial cancer.

Abnormally elevated EZH2-mediated H3K27me3 enhances osteogenesis in aortic valve interstitial cells by inhibiting SOCS3 expression

BACKGROUND AND AIMS

The osteogenic transition of aortic valve interstitial cells (AVICs) plays a critical role for the progression of calcific aortic valve disease (CAVD). Enhancer of zeste homolog 2 (EZH2) is an important methyltransferase for histone H3 Lys27 (H3K27) that has been found to be involved in osteogenesis. Here, we investigated the effect and mechanism of EZH2 in CAVD progression.

METHODS

High throughout mRNA sequencing, qRT-PCR and immunoblot were performed to screen differentially expressed genes in non-CAVD and CAVD aortic valves. To investigate the role of EZH2 and SOCS3 in osteogenesis, AVICs were treated with siRNA, adenovirus and specific inhibitors, then osteogenic markers and mineralized deposits were examined. In vivo, the morphology and function of aortic valves were investigated by HE stain and echocardiography in ApoE^-/- mice fed a long-term western diet (WD).

RESULTS

We discovered that EZH2 was upregulated and SOCS3 was downregulated in calcified aortic valves. In AVICs, inhibition or silencing of EZH2 attenuated the osteogenic responses. On the other hand, demethylases inhibitor (GSK-J4) enhanced osteogenic transition of AVICs. Moreover, SOCS3 knockdown enhanced the expression of osteogenic markers, while SOCS3 overexpression suppressed osteogenesis and calcification. The chromatin immunoprecipitation and restored experiments indicated that EZH2 directly targeted SOCS3 to promote osteogenic responses of AVICs. In vivo, treatment with EZH2 inhibitor through intraperitoneal injection attenuated aortic valve thickening, calcification and dysfunction induced by WD.

CONCLUSIONS

Collectively, we found that EZH2-mediated H3K27me3 enhanced osteogenesis and microcalcification of AVICs via inhibiting SOCS3 expression, which provides potential targets for future therapeutic interventions of CAVD.

Dihydromyricetin ameliorates osteogenic differentiation of human aortic valve interstitial cells by targeting c-KIT/interleukin-6 signaling pathway

Aims: Calcific aortic valve disease (CAVD) is a chronic cardiovascular disease with high morbidity that lacks effective pharmacotherapeutics. As a natural flavonoid extracted from Ampelopsis grossedentata, dihydromyricetin (DHM) has been shown to be effective in protecting against atherosclerosis; yet, the therapeutic role of DHM in CAVD remains poorly understood. Herein, we aimed to clarify the therapeutic implications of DHM in CAVD and the underlying molecular mechanisms in human valvular interstitial cells (hVICs). Methods and Results: The protein levels of two known osteogenesis-specific genes (alkaline phosphatase, ALP; runt-related transcription factor 2, Runx2) and calcified nodule formation in hVICs were detected by Western blot and Alizarin Red staining, respectively. The results showed that DHM markedly ameliorated osteogenic induction medium (OM)-induced osteogenic differentiation of hVICs, as evidenced by downregulation of ALP and Runx2 expression and decreased calcium deposition. The SwissTargetPrediction database was used to identify the potential AVC-associated direct protein target of DHM. Protein-protein interaction (PPI) analysis revealed that c-KIT, a tyrosine-protein kinase, can act as a credible protein target of DHM, as evidenced by molecular docking. Mechanistically, DHM-mediated inhibition of c-KIT phosphorylation drove interleukin-6 (IL-6) downregulation in CAVD, thereby ameliorating OM-induced osteogenic differentiation of hVICs and aortic valve calcification progression. Conclusion: DHM ameliorates osteogenic differentiation of hVICs by blocking the phosphorylation of c-KIT, thus reducing IL-6 expression in CAVD. DHM could be a viable therapeutic supplement to impede CAVD.

Tripartite motif 25 ameliorates doxorubicin-induced cardiotoxicity by degrading p85α

Doxorubicin (DOX)-based chemotherapy is widely used to treat malignant tumors; however, the cardiotoxicity induced by DOX restricts its clinical usage. A therapeutic dose of DOX can activate ubiquitin-proteasome system. However, whether and how ubiquitin-proteasome system brings out DOX-induced cardiotoxicity remains to be investigated. Here we conducted a proteomics analysis of a DOX-induced cardiotoxicity model to screen the potentially ubiquitination-related molecules. Dysregulated TRIM25 was found to contribute to the cardiotoxicity. In vivo and in vitro cardiotoxicity experiments revealed that TRIM25 ameliorated DOX-induced cardiotoxicity. Electron microscopy and endoplasmic reticulum stress markers revealed that TRIM25 mitigated endoplasmic reticulum stress and apoptosis in DOX-induced cardiomyocytes. Mechanistically, the Co-immunoprecipitation assays and CHX pulse-chase experiment determined that TRIM25 affected p85α stability and promoted its ubiquitination and degradation. This leads to increase of nuclear translocation of XBP-1s, which mitigates endoplasmic reticulum stress. These findings reveal that TRIM25 may have a therapeutic role for DOX-induced cardiotoxicity.

Uncoupling the Vicious Cycle of Mechanical Stress and Inflammation in Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD) is a common acquired valvulopathy, which carries a high burden of mortality. Chronic inflammation has been postulated as the predominant pathophysiological process underlying CAVD. So far, no effective medical therapies exist to halt the progression of CAVD. This review aims to outline the known pathways of inflammation and calcification in CAVD, focussing on the critical roles of mechanical stress and mechanosensing in the perpetuation of valvular inflammation. Following initiation of valvular inflammation, dysregulation of proinflammatory and osteoregulatory signalling pathways stimulates endothelial-mesenchymal transition of valvular endothelial cells (VECs) and differentiation of valvular interstitial cells (VICs) into active myofibroblastic and osteoblastic phenotypes, which in turn mediate valvular extracellular matrix remodelling and calcification. Mechanosensitive signalling pathways convert mechanical forces experienced by valve leaflets and circulating cells into biochemical signals and may provide the positive feedback loop that promotes acceleration of disease progression in the advanced stages of CAVD. Mechanosensing is implicated in multiple aspects of CAVD pathophysiology. The mechanosensitive RhoA/ROCK and YAP/TAZ systems are implicated in aortic valve leaflet mineralisation in response to increased substrate stiffness. Exposure of aortic valve leaflets, endothelial cells and platelets to high shear stress results in increased expression of mediators of VIC differentiation. Upregulation of the Piezo1 mechanoreceptor has been demonstrated to promote inflammation in CAVD, which normalises following transcatheter valve replacement. Genetic variants and inhibition of Notch signalling accentuate VIC responses to altered mechanical stresses. The study of mechanosensing pathways has revealed promising insights into the mechanisms that perpetuate inflammation and calcification in CAVD. Mechanotransduction of altered mechanical stresses may provide the sought-after coupling link that drives a vicious cycle of chronic inflammation in CAVD. Mechanosensing pathways may yield promising targets for therapeutic interventions and prognostic biomarkers with the potential to improve the management of CAVD.

Calcific aortic valve disease: from molecular and cellular mechanisms to medical therapy

Calcific aortic valve disease (CAVD) is a highly prevalent condition that comprises a disease continuum, ranging from microscopic changes to profound fibro-calcific leaflet remodelling, culminating in aortic stenosis, heart failure, and ultimately premature death. Traditional risk factors, such as hypercholesterolaemia and (systolic) hypertension, are shared among atherosclerotic cardiovascular disease and CAVD, yet the molecular and cellular mechanisms differ markedly. Statin-induced low-density lipoprotein cholesterol lowering, a remedy highly effective for secondary prevention of atherosclerotic cardiovascular disease, consistently failed to impact CAVD progression or to improve patient outcomes. However, recently completed phase II trials provide hope that pharmaceutical tactics directed at other targets implicated in CAVD pathogenesis offer an avenue to alter the course of the disease non-invasively. Herein, we delineate key players of CAVD pathobiology, outline mechanisms that entail compromised endothelial barrier function, and promote lipid homing, immune-cell infiltration, and deranged phospho-calcium metabolism that collectively perpetuate a pro-inflammatory/pro-osteogenic milieu in which valvular interstitial cells increasingly adopt myofibro-/osteoblast-like properties, thereby fostering fibro-calcific leaflet remodelling and eventually resulting in left ventricular outflow obstruction. We provide a glimpse into the most promising targets on the horizon, including lipoprotein(a), mineral-binding matrix Gla protein, soluble guanylate cyclase, dipeptidyl peptidase-4 as well as candidates involved in regulating phospho-calcium metabolism and valvular angiotensin II synthesis and ultimately discuss their potential for a future therapy of this insidious disease.