Celastrol Alleviates Aortic Valve Calcification Via Inhibition of NADPH Oxidase 2 in Valvular Interstitial Cells

Diabetes and calcific aortic valve disease: implications of glucose-lowering medication as potential therapy

Calcific aortic valve disease (CAVD) is a progressive disease, of which the 2-year mortality is >50% for symptomatic disease. However, there are currently no pharmacotherapies to prevent the progression of CAVD unless transcatheter or surgical aortic valve replacement is performed. The prevalence of diabetes among CAVD has increased rapidly in recent decades, especially among those undergoing aortic valve replacement. Diabetes and its comorbidities, such as hypertension, hyperlipidemia, chronic kidney disease and ageing, participated jointly in the initiation and progression of CAVD, which increased the management complexity in patients with CAVD. Except from hyperglycemia, the molecular links between diabetes and CAVD included inflammation, oxidative stress and endothelial dysfunction. Traditional cardiovascular drugs like lipid-lowering agents and renin-angiotensin system blocking drugs have proven to be unsuccessful in retarding the progression of CAVD in clinical trials. In recent years, almost all kinds of glucose-lowering medications have been specifically assessed for decelerating the development of CAVD. Based on the efficacy for atherosclerotic cardiovascular disease and CAVD, this review summarized current knowledge about glucose-lowering medications as promising treatment options with the potential to retard CAVD.

Cardiac protection of wogonin in mice with pulmonary fibrosis by regulating Sirt1/ γ-H2AX pathway

Background

Clinical evidence suggests that pulmonary fibrosis (PF) and heart failure (HF) often co-exist; however, the specific impact of PF on HF remains underexplored. This gap in understanding complicates the management and treatment of HF in patients with PF.

Objectives

To investigate the effects of PF on cardiac function and myocardial fibrosis using a mouse PF model and evaluate the therapeutic potential of wogonin, a flavonoid compound known for its anti-PF properties.

Methods

A PF mouse model was established via intratracheal administration of bleomycin (BLM). Starting on day 8 post-BLM treatment, wogonin (50 mg/kg) was intraperitoneally administered every 2 days for 2 weeks. Cardiac function was assessed using echocardiography, while myocardial fibrosis was evaluated through Masson staining. In vitro, H9C2 cardiomyocytes were exposed to CoCl2 or H2O2 for 24 h with or without wogonin (20 μM) treatment. Apoptosis and DNA damage markers were analysed using immunofluorescence, immunoblotting, and the Comet assay. The interaction between wogonin and Sirt1 was examined using biotin-affinity pulldown assays and molecular docking simulations.

Results

Mice with PF exhibited significant cardiac dysfunction and myocardial fibrosis. Wogonin treatment markedly improved ejection fraction and attenuated myocardial fibrosis in PF mice. Mechanistic studies revealed that wogonin alleviated DNA damage and cardiomyocyte apoptosis by upregulating Sirt1 and downregulating γ-H2AX expression. Docking simulations predicted that wogonin forms a stable complex with Sirt1 through hydrogen-bonding and hydrophobic interactions, which was further validated by biotin-affinity pulldown assays.

Conclusion

Wogonin exerts protective effects against cardiac dysfunction and fibrosis in PF mice by modulating Sirt1/γ-H2AX-mediated pathways to reduce DNA damage and apoptosis. These findings suggest the potential of wogonin as a therapeutic agent for managing HF associated with PF.

Understanding chronic inflammation: couplings between cytokines, ROS, NO, Cai 2+, HIF-1α, Nrf2 and autophagy

Chronic inflammation is an important component of many diseases, including autoimmune diseases, intracellular infections, dysbiosis and degenerative diseases. An important element of this state is the mainly positive feedback between inflammatory cytokines, reactive oxygen species (ROS), nitric oxide (NO), increased intracellular calcium, hypoxia-inducible factor 1-alpha (HIF-1α) stabilisation and mitochondrial oxidative stress, which, under normal conditions, enhance the response against pathogens. Autophagy and the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant response are mainly negatively coupled with the above-mentioned elements to maintain the defence response at a level appropriate to the severity of the infection. The current review is the first attempt to build a multidimensional model of cellular self-regulation of chronic inflammation. It describes the feedbacks involved in the inflammatory response and explains the possible pathways by which inflammation becomes chronic. The multiplicity of positive feedbacks suggests that symptomatic treatment of chronic inflammation should focus on inhibiting multiple positive feedbacks to effectively suppress all dysregulated elements including inflammation, oxidative stress, calcium stress, mito-stress and other metabolic disturbances.

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.

Niclosamide attenuates calcification in human heart valvular interstitial cells through inhibition of the AMPK/mTOR signaling pathway

Calcific aortic valve disease (CAVD) is a considerable health burden with a lack of effective therapeutic options. There is an urgent need to develop interventions that inhibit the osteogenic transformation of valvular interstitial cells (VICs) and delay the calcification process. Niclosamide, an FDA-approved anti-helminthic drug, has emerged as a promising candidate that demonstrates a negative regulatory effect on porcine VICs calcification. However, its molecular mechanism in human VICs (hVICs) remains to be investigated. In this study, high-resolution mass spectrometry-based proteomics and phosphoproteomics were employed, and 8373 proteins and 3697 phosphosites were identified in hVICs treated with a pro-calcifying medium and niclosamide. The quantitative proteomic and phosphoproteomic analysis resulted in the identification of calcification markers and osteogenesis-associated proteins. Bioinformatic analysis of the protein-protein interaction network and affected kinase prediction revealed that the AMPK/mTOR/p70S6K signaling cascade was altered upon calcific induction and niclosamide treatment. Further validation indicated that niclosamide inhibited the calcification of hVICs by targeting the mammalian target of the rapamycin (mTOR) signaling pathway. This study provides the first evidence that niclosamide could prevent osteoblastic differentiation in hVICs partially through the inhibition of the AMPK/mTOR/p70S6k signaling pathway, thereby mitigating hVICs calcification. These findings present a foundation for potential therapeutic strategies to impede the progression of CAVD and provide valuable insights into the pharmacological effects of niclosamide on human VICs.

Elucidating common biomarkers and pathways of osteoporosis and aortic valve calcification: insights into new therapeutic targets

BACKGROUND

Osteoporosis and aortic valve calcification, prevalent in the elderly, have unclear common mechanisms. This study aims to uncover them through bioinformatics analysis.

METHODS

Microarray data from GEO was analyzed for osteoporosis and aortic valve calcification. Differential expression analysis identified co-expressed genes. SVM-RFE and random forest selected key genes. GO and KEGG enrichment analyses were performed. Immunoinfiltration and GSEA analyses were subsequently performed. NetworkAnalyst analyzed microRNAs/TFs. HERB predicted drugs, and molecular docking assessed targeting potential.

RESULTS

Thirteen genes linked to osteoporosis and aortic valve calcification were identified. TNFSF11, KYNU, and HLA-DMB emerged as key genes. miRNAs, TFs, and drug predictions offered therapeutic insights. Molecular docking suggested 17-beta-estradiol and vitamin D3 as potential treatments.

CONCLUSION

The study clarifies shared mechanisms of osteoporosis and aortic valve calcification, identifies biomarkers, and highlights TNFSF11, KYNU, and HLA-DMB. It also suggests 17-beta-estradiol and vitamin D3 as potential effective treatments.

Wogonin protects against bleomycin-induced mouse pulmonary fibrosis via the inhibition of CDK9/p53-mediated cell senescence

Pulmonary fibrosis (PF) is a fatal interstitial lung disease associated with declining pulmonary function but currently with few effective drugs. Cellular senescence has been implicated in the pathogenesis of PF and could be a potential therapeutic target. Emerging evidence suggests wogonin, the bioactive compound isolated from Scutellaria baicalensis, owns the anti-senescence properties, however, the possible impact of wogonin on PF and the potential mechanisms remain unclear. In this study, a well-established mouse model of PF was utilized which mice were administrated with bleomycin (BLM). Strikingly, wogonin treatment significantly reduced fibrosis deposition in the lung induced by BLM. In vitro, wogonin also suppressed fibrotic markers of cultured epithelial cells stimulated by BLM or hydrogen peroxide. Mechanistic investigation revealed that wogonin attenuated the expressions of DNA damage marker γ-H2AX and senescence-related markers including phosphorylated p53, p21, retinoblastoma protein (pRB), and senescence-associated β-galactosidase (SA-β-gal). Moreover, wogonin, as a direct and selective inhibitor of cyclin-dependent kinase 9 (CDK9), exhibited anti-fibrotic capacity by inhibiting CDK9 and p53/p21 signalling. In conclusion, wogonin protects against BLM-induced PF in mice through the inhibition of cell senescence via the regulation of CDK9/p53 and DNA damage pathway. This is the first study to demonstrate the beneficial effect of wogonin on PF, and its implication as a novel candidate for PF therapy.

Pathological Mechanism and Treatment of Calcified Aortic Stenosis

Calcified aortic stenosis (AS) is one of the most common valvular heart diseases worldwide, characterized by progressive fibrocalcific remodeling and thickening of the leaflets, which ultimately leads to obstruction of blood flow. Its pathobiology is an active and complicated process, involving endothelial cell dysfunction, lipoprotein deposition and oxidation, chronic inflammation, phenotypic transformation of valve interstitial cells, neovascularization, and intravalvular hemorrhage. To date, no targeted drug has been proven to slow down or prevent disease progression. Aortic valve replacement is still the optimal treatment of AS. This article reviews the etiology, diagnosis, and management of calcified aortic stenosis and proposes novel potential therapeutic targets.

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.

Lysyl Oxidase in Ectopic Cardiovascular Calcification: Role of Oxidative Stress

Lysyl oxidase (LOX)-mediated extracellular matrix crosslinking modulates calcification in atherosclerosis and aortic valve disease; however, this enzyme also induces oxidative stress. We addressed the contribution of LOX-dependent oxidative stress to cardiovascular calcification. LOX is upregulated in human-calcified atherosclerotic lesions and atheromas from atherosclerosis-challenged LOX transgenic mice (TgLOXVSMC) and colocalized with a marker of oxidative stress (8-oxo-deoxyguanosine) in vascular smooth muscle cells (VSMCs). Similarly, in calcific aortic valves, high LOX expression was detected in valvular interstitial cells (VICs) positive for 8-oxo-deoxyguanosine, while LOX and LOXL2 expression correlated with osteogenic markers (SPP1 and RUNX2) and NOX2. In human VICs, mito-TEMPO and TEMPOL attenuated the increase in superoxide anion levels and the mineralization induced by osteogenic media (OM). Likewise, in OM-exposed VICs, β-aminopropionitrile (a LOX inhibitor) ameliorated both oxidative stress and calcification. Gain- and loss-of-function approaches in VICs demonstrated that while LOX silencing negatively modulates oxidative stress and calcification induced by OM, lentiviral LOX overexpression exacerbated oxidative stress and VIC calcification, effects that were prevented by mito-TEMPO, TEMPOL, and β-aminopropionitrile. Our data indicate that LOX-induced oxidative stress participates in the procalcifying effects of LOX activity in ectopic cardiovascular calcification, and highlight the multifaceted role played by LOX isoenzymes in cardiovascular diseases.

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.

Albumin Redox Modifications Promote Cell Calcification Reflecting the Impact of Oxidative Status on Aortic Valve Disease and Atherosclerosis

Calcific aortic valve disease (CAVD) and coronary artery disease (CAD) are related cardiovascular diseases in which common mechanisms lead to tissue calcification. Oxidative stress plays a key role in these diseases and there is also evidence that the redox state of serum albumin exerts a significant influence on these conditions. To further explore this issue, we used multimarker scores (OxyScore and AntioxyScore) to assess the global oxidative status in patients with CAVD, with and without CAD, also evaluating their plasma thiol levels. In addition, valvular interstitial cells were treated with reduced, oxidized, and native albumin to study how this protein and its modifications affect cell calcification. The differences we found suggest that oxidative status is distinct in CAVD and CAD, with differences in redox markers and thiol levels. Importantly, the in vitro interstitial cell model revealed that modified albumin affects cell calcification, accelerating this process. Hence, we show here the importance of the redox system in the development of CAVD, emphasizing the relevance of multimarker scores, while also offering evidence of how the redox state of albumin influences vascular calcification. These data highlight the relevance of understanding the overall redox processes involved in these diseases, opening the door to new studies on antioxidants as potential therapies for these patients.

Niclosamide Inhibits Aortic Valve Interstitial Cell Calcification by Interfering with the GSK-3β/β-Catenin Signaling Pathway

The most common heart valve disorder is calcific aortic valve stenosis (CAVS), which is characterized by a narrowing of the aortic valve. Treatment with the drug molecule, in addition to surgical and transcatheter valve replacement, is the primary focus of researchers in this field. The purpose of this study is to determine whether niclosamide can reduce calcification in aortic valve interstitial cells (VICs). To induce calcification, cells were treated with a pro-calcifying medium (PCM). Different concentrations of niclosamide were added to the PCM-treated cells, and the level of calcification, mRNA, and protein expression of calcification markers was measured. Niclosamide inhibited aortic valve calcification as observed from reduced alizarin red s staining in niclosamide treated VICs and also decreased the mRNA and protein expressions of calcification-specific markers: runt-related transcription factor 2 and osteopontin. Niclosamide also reduced the formation of reactive oxygen species, NADPH oxidase activity and the expression of Nox2 and p22phox. Furthermore, in calcified VICs, niclosamide inhibited the expression of β-catenin and phosphorylated glycogen synthase kinase (GSK-3β), as well as the phosphorylation of AKT and ERK. Taken together, our findings suggest that niclosamide may alleviate PCM-induced calcification, at least in part, by targeting oxidative stress mediated GSK-3β/β-catenin signaling pathway via inhibiting activation of AKT and ERK, and may be a potential treatment for CAVS.

Celastrol functions as an emerging manager of lipid metabolism: Mechanism and therapeutic potential

Lipid metabolism disorders are pivotal in the development of various lipid-related diseases, such as obesity, atherosclerosis, non-alcoholic fatty liver disease, type 2 diabetes, and cancer. Celastrol, a bioactive compound extracted from the Chinese herb Tripterygium wilfordii Hook F, has recently demonstrated potent lipid-regulating abilities and promising therapeutic effects for lipid-related diseases. There is substantial evidence indicating that celastrol can ameliorate lipid metabolism disorders by regulating lipid profiles and related metabolic processes, including lipid synthesis, catabolism, absorption, transport, and peroxidation. Even wild-type mice show augmented lipid metabolism after treatment with celastrol. This review aims to provide an overview of recent advancements in the lipid-regulating properties of celastrol, as well as to elucidate its underlying molecular mechanisms. Besides, potential strategies for targeted drug delivery and combination therapy are proposed to enhance the lipid-regulating effects of celastrol and avoid the limitations of its clinical application.

The Promising Therapeutic Potential of Celastrol for Fibrotic Diseases: A Systematic Literature Review on Its Mechanism

Celastrol is a pentacyclic tripterine sourced from Tripterygium wilfordii hook root. Celastrol can exert certain biological functions such as antitumor, anti-inflammatory, and antiproliferative properties. Celastrol was shown from the previous literature to be capable of attenuating many fibrotic diseases. As the effects of various fibrotic diseases such as atherosclerosis, cancer, and ischemia affect more people with devastating repercussions, this warrants celastrol to be exploited as a phytotherapeutic drug. The purpose of this study is to review previous research and identify the proposed therapeutic mechanisms of celastrol in fibrotic diseases focusing on both the in vitro and in vivo experimental models.  A systematic literature search on Web of Science (WoS), Scopus, and ScienceDirect that included articles published between 2012 and 2022 was carried out using the keywords "celastrol", "tripterine", "fibrotic disease", and "fibrosis". After screening the initial search yield of 405 articles, 25 articles were included in this review.  The study findings summarize the potential therapeutic mechanism of celastrol in the attenuation of fibrotic diseases in in vivo and in vitro experimental models. It shows that celastrol is useful as a treatment means. However, more studies are needed on the effects of celastrol on humans to carry out clinical trials to verify the long-term benefits of celastrol.

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.

Calcific aortic valve disease: mechanisms, prevention and treatment

Calcific aortic valve disease (CAVD) is the most common disorder affecting heart valves and is characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. Analyses of surgically explanted aortic valve leaflets have shown that dystrophic mineralization and osteogenic transition of valve interstitial cells co-occur with neovascularization, microhaemorrhage and abnormal production of extracellular matrix. Age and congenital bicuspid aortic valve morphology are important and unalterable risk factors for CAVD, whereas additional risk is conferred by elevated blood pressure and plasma lipoprotein(a) levels and the presence of obesity and diabetes mellitus, which are modifiable factors. Genetic and molecular studies have identified that the NOTCH, WNT-β-catenin and myocardin signalling pathways are involved in the control and commitment of valvular cells to a fibrocalcific lineage. Complex interactions between valve endothelial and interstitial cells and immune cells promote the remodelling of aortic valve leaflets and the development of CAVD. Although no medical therapy is effective for reducing or preventing the progression of CAVD, studies have started to identify actionable targets.

Structure, Activation, and Regulation of NOX2: At the Crossroad between the Innate Immunity and Oxidative Stress-Mediated Pathologies

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) is a multisubunit enzyme complex that participates in the generation of superoxide or hydrogen peroxide (H₂O₂) and plays a key role in several biological functions. Among seven known NOX isoforms, NOX2 was the first identified in phagocytes but is also expressed in several other cell types including endothelial cells, platelets, microglia, neurons, and muscle cells. NOX2 has been assigned multiple roles in regulating many aspects of innate and adaptive immunity, and human and mouse models of NOX2 genetic deletion highlighted this key role. On the other side, NOX2 hyperactivation is involved in the pathogenesis of several diseases with different etiologies but all are characterized by an increase in oxidative stress and inflammatory process. From this point of view, the modulation of NOX2 represents an important therapeutic strategy aimed at reducing the damage associated with its hyperactivation. Although pharmacological strategies to selectively modulate NOX2 are implemented thanks to new biotechnologies, this field of research remains to be explored. Therefore, in this review, we analyzed the role of NOX2 at the crossroads between immunity and pathologies mediated by its hyperactivation. We described (1) the mechanisms of activation and regulation, (2) human, mouse, and cellular models studied to understand the role of NOX2 as an enzyme of innate immunity, (3) some of the pathologies associated with its hyperactivation, and (4) the inhibitory strategies, with reference to the most recent discoveries.

Celastrol: The new dawn in the treatment of vascular remodeling diseases

Evidence is mounting that abnormal vascular remodeling leads to many cardiovascular diseases (CVDs). This suggests that vascular remodeling can be a crucial target for the prevention and treatment of CVDs. Recently, celastrol, an active ingredient of the broadly used Chinese herb Tripterygium wilfordii Hook F, has attracted extensive interest for its proven potential to improve vascular remodeling. Substantial evidence has shown that celastrol improves vascular remodeling by ameliorating inflammation, hyperproliferation, and migration of vascular smooth muscle cells, vascular calcification, endothelial dysfunction, extracellular matrix remodeling, and angiogenesis. Moreover, numerous reports have proven the positive effects of celastrol and its therapeutic promise in treating vascular remodeling diseases such as hypertension, atherosclerosis, and pulmonary artery hypertension. The present review summarizes and discusses the molecular mechanism of celastrol regulating vascular remodeling and provides preclinical proof for future clinical applications of celastrol.

Natural Bioactive Compounds Targeting NADPH Oxidase Pathway in Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, in both developed and developing countries. According to the WHO report, the morbidity and mortality caused by CVD will continue to rise with the estimation of death going up to 22.2 million in 2030. NADPH oxidase (NOX)-derived reactive oxygen species (ROS) production induces endothelial nitric oxide synthase (eNOS) uncoupling and mitochondrial dysfunction, resulting in sustained oxidative stress and the development of cardiovascular diseases. Seven distinct members of the family have been identified of which four (namely, NOX1, 2, 4 and 5) may have cardiovascular functions. Currently, the treatment and management plan for patients with CVDs mainly depends on the drugs. However, prolonged use of prescribed drugs may cause adverse drug reactions. Therefore, it is crucial to find alternative treatment options with lesser adverse effects. Natural products have been gaining interest as complementary therapy for CVDs over the past decade due to their wide range of medicinal properties, including antioxidants. These might be due to their potent active ingredients, such as flavonoid and phenolic compounds. Numerous natural compounds have been demonstrated to have advantageous effects on cardiovascular disease via NADPH cascade. This review highlights the potential of natural products targeting NOX-derived ROS generation in treating CVDs. Emphasis is put on the activation of the oxidases, including upstream or downstream signalling events.

Therapie der Aortenklappenstenose jenseits des Klappenersatzes – Was bringt die Zukunft?

Die kalzifizierende Aortenklappenstenose stellt die häufigste interventionell oder operativ behandlungsbedürftige Herzklappenerkrankung im Erwachsenenalter dar und betrifft insbesondere Menschen höheren Lebensalters. Obwohl der Fortschritt interventioneller Therapieoptionen die Behandlung der Aortenklappenstenose in den letzten Jahren verbessern konnte, ist die symptomatische Aortenklappenstenose weiterhin mit hoher Morbidität und Letalität assoziiert. Ihre Pathophysiologie ist gekennzeichnet durch eine Fibrosierung und Kalzifizierung der Klappentaschen, welche zu deren progredienter Verdickung und Versteifung und letztendlich zur Obstruktion der Klappe mit erschwertem Blutfluss in die Aorta führen. Da sich die Betroffenen meist im fortgeschrittenen Alter befinden und weitere Begleiterkrankungen aufweisen, ist ein operativer oder interventioneller Ersatz der Aortenklappe mit einem höheren Eingriffsrisiko und verlängerter Rekonvaleszenzzeit der Patienten verbunden. Die häufig begleitend auftretende periphere vaskuläre Verschlusskrankheit kann die Nutzung der peripheren Zugangswege im Rahmen des transluminalen Vorgehens unmöglich machen und die transapikale Punktion mit konsekutiv erhöhtem Eingriffsrisiko erfordern.

Eine limitierte Lebenserwartung, z. B. im Rahmen von neoplastischen Erkrankungen, kann darüber hinaus eine Kontraindikation zur operativen und interventionellen Versorgung darstellen.

Aktuell gibt es keine spezifische medikamentöse Therapie, die Initiation und Progression dieser bedeutenden Erkrankung beeinflussen kann und eine Alternative zum Klappenersatz für diese vulnerablen Patientenkollektive darstellt. Ein besseres Verständnis der zugrunde liegenden komplexen Pathophysiologie hat zur Entwicklung und Erprobung innovativer medikamentöser Therapieansätze geführt. Diese neuartigen Therapien befinden sich im Moment allesamt noch in Prüfung durch präklinische und klinische Studien und sollen in diesem Übersichtsartikel adressiert werden.

Integrated identification of key immune related genes and patterns of immune infiltration in calcified aortic valvular disease: A network based meta-analysis

Background: As the most prevalent valvular heart disease, calcific aortic valve disease (CAVD) has become a primary cause of aortic valve stenosis and insufficiency. We aim to illustrate the roles of immune related genes (IRGs) and immune cells infiltration in the occurrence of CAVD.

Methods: Integrative meta-analysis of expression data (INMEX) was adopted to incorporate multiple gene expression datasets of CAVD from Gene Expression Omnibus (GEO) database. By matching the differentially expressed genes (DEGs) to IRGs from “ImmPort” database, differentially expressed immune related genes (DEIRGs) were screened out. We performed enrichment analysis and found that DEIRGs in CAVD were closely related to inflammatory response and immune cells infiltration. We also constructed protein–protein interaction (PPI) network of DEIRGs and identified 5 key DEIRGs in CAVD according to the mixed character calculation results. Moreover, CIBERSORT algorithm was used to explore the profile of infiltrating immune cells in CAVD. Based on Spearman’s rank correlation method, correlation analysis between key DEIRGs and infiltrating immune cells was performed.

Results: A total of 220 DEIRGs were identified and the enrichment analysis of DEIRGs showed that they were significantly enriched in inflammatory responses. PPI network was constructed and PTPN11, GRB2, SYK, PTPN6 and SHC1 were identified as key DEIRGs. Compared with normal aortic valve tissue samples, the proportion of neutrophils, T cells CD4 memory activated and macrophages M0 was elevated in calcified aortic valves tissue samples, as well as reduced infiltration of macrophages M2 and NK cells activated. Furthermore, key DEIRGs identified in the present study, including PTPN11, GRB2, PTPN6, SYK, and SHC1, were all significantly correlated with infiltration of various immune cells.

Conclusion: This meta-analysis suggested that PTPN11, GRB2, PTPN6, SYK, and SHC1 might be key DEIRGs associated with immune cells infiltration, which play a pivotal role in pathogenesis of CAVD.

Contribution of Oxidative Stress (OS) in Calcific Aortic Valve Disease (CAVD): From Pathophysiology to Therapeutic Targets

Calcific aortic valve disease (CAVD) is a major cause of cardiovascular mortality and morbidity, with increased prevalence and incidence. The underlying mechanisms behind CAVD are complex, and are mainly illustrated by inflammation, mechanical stress (which induces prolonged aortic valve endothelial dysfunction), increased oxidative stress (OS) (which trigger fibrosis), and calcification of valve leaflets. To date, besides aortic valve replacement, there are no specific pharmacological treatments for CAVD. In this review, we describe the mechanisms behind aortic valvular disease, the involvement of OS as a fundamental element in disease progression with predilection in AS, and its two most frequent etiologies (calcific aortic valve disease and bicuspid aortic valve); moreover, we highlight the potential of OS as a future therapeutic target.

Celastrol: A Promising Agent Fighting against Cardiovascular Diseases

Cardiovascular diseases (CVD) are leading causes of morbidity and mortality worldwide; therefore, seeking effective therapeutics to reduce the global burden of CVD has become increasingly urgent. Celastrol, a bioactive compound isolated from the roots of the plant Tripterygium wilfordii (TW), has been attracting increasing research attention in recent years, as it exerts cardiovascular treatment benefits targeting both CVD and their associated risk factors. Substantial evidence has revealed a protective role of celastrol against a broad spectrum of CVD including obesity, diabetes, atherosclerosis, cerebrovascular injury, calcific aortic valve disease and heart failure through complicated and interlinked mechanisms such as direct protection against cardiomyocyte hypertrophy and death, and indirect action on oxidation and inflammation. This review will mainly summarize the beneficial effects of celastrol against CVD, largely based on in vitro and in vivo preclinical studies, and the potential underlying mechanisms. We will also briefly discuss celastrol’s pharmacokinetic limitations, which hamper its further clinical applications, and prospective future directions.

Marine-Derived Piericidin Diglycoside S18 Alleviates Inflammatory Responses in the Aortic Valve via Interaction with Interleukin 37

Calcific aortic valve disease (CAVD) is a valvular disease frequently in the elderly individuals that can lead to the valve dysfunction. Osteoblastic differentiation of human aortic valve interstitial cells (HAVICs) induced by inflammation play a crucial role in CAVD pathophysiological processes. To date, no effective drugs for CAVD have been established, and new agents are urgently needed. Piericidin glycosides, obtained from a marine-derived Streptomyces strain, were revealed to have regulatory effects on mitochondria in previous studies. Here, we discovered that 13-hydroxypiericidin A 10-O-α-D-glucose (1→6)-β-D-glucoside (S18), a specific piericidin diglycoside, suppresses lipopolysaccharide- (LPS) induced inflammatory responses of HAVICs by alleviating mitochondrial stress in an interleukin (IL)-37-dependent manner. Knockdown of IL-37 by siRNA not only exaggerated LPS-induced HAVIC inflammation and mitochondrial stress but also abrogated the anti-inflammatory effect of S18 on HAVICs. Moreover, S18 alleviated aortic valve lesions in IL-37 transgenic mice of CAVD model. Microscale thermophoresis (MST) and docking analysis of five piericidin analogues suggested that diglycosides, but not monoglycosides, exert obvious IL-37-binding activity. These results indicate that S18 directly binds to IL-37 to alleviate inflammatory responses in HAVICs and aortic valve lesions in mice. Piericidin diglycoside S18 is a potential therapeutic agent to prevent the development of CAVD.

4-Octyl itaconate suppresses the osteogenic response in aortic valvular interstitial cells via the Nrf2 pathway and alleviates aortic stenosis in mice with direct wire injury

Calcific aortic valve disease (CAVD) is the most prevalent valvular heart disease in older individuals, but there is a lack of drug treatment. The cellular biological mechanisms of CAVD are still unclear. Oxidative stress and endoplasmic reticulum stress (ER stress) have been suggested to be involved in the progression of CAVD. Many studies have demonstrated that 4-octyl itaconate (OI) plays beneficial roles in limiting inflammation and oxidative injury. However, the potential role of OI in CAVD has not been thoroughly explored. Thus, we investigated OI-mediated modulation of ROS generation and endoplasmic reticulum stress to inhibit osteogenic differentiation in aortic valve interstitial cells (VICs). In our study, calcified aortic valves showed increased levels of ER stress and superoxide anion, as well as abnormal expression of Hmox1 and NQO1. In VICs, OI activated the Nrf2 signaling cascade and contributed to Nrf2 stabilization and nuclear translocation, thus augmenting the expression of genes downstream of Nrf2 (Hmox1 and NQO1). Moreover, OI ameliorated osteogenic medium (OM)-induced ROS production, mitochondrial ROS levels and the loss of mitochondrial membrane potential in VICs. Furthermore, OI attenuated the OM-induced upregulation of ER stress markers, osteogenic markers and calcium deposition, which were blocked by the Nrf2-specific inhibitor ML385. Interestingly, we found that OM-induced ER stress and osteogenic differentiation were ROS-dependent and that Hmox1 silencing triggered ROS production, ER stress and elevated osteogenic activity, which were inhibited by NAC. Overexpression of NQO1 mediated by adenovirus vectors significantly suppressed OM-induced ER stress and osteogenic markers. Collectively, these results showed the anti-osteogenic effects of OI on AVICs by regulating the generation of ROS and ER stress by activating the Nrf2 signaling pathway. Furthermore, OI alleviated aortic stenosis in a mouse model with direct wire injury. Due to its antioxidant properties, OI could be a potential drug for the prevention and/or treatment of CAVD.

The mechanistic pathways of oxidative stress in aortic stenosis and clinical implications

Despite the elucidation of the pathways behind the development of aortic stenosis (AS), there remains no effective medical treatment to slow or reverse its progress. Instead, the gold standard of care in severe or symptomatic AS is replacement of the aortic valve. Oxidative stress is implicated, both directly as well as indirectly, in lipid infiltration, inflammation and fibro-calcification, all of which are key processes underlying the pathophysiology of degenerative AS. This culminates in the breakdown of the extracellular matrix, differentiation of the valvular interstitial cells into an osteogenic phenotype, and finally, calcium deposition as well as thickening of the aortic valve. Oxidative stress is thus a promising and potential therapeutic target for the treatment of AS. Several studies focusing on the mitigation of oxidative stress in the context of AS have shown some success in animal and in vitro models, however similar benefits have yet to be seen in clinical trials. Statin therapy, once thought to be the key to the treatment of AS, has yielded disappointing results, however newer lipid lowering therapies may hold some promise. Other potential therapies, such as manipulation of microRNAs, blockade of the renin-angiotensin-aldosterone system and the use of dipeptidylpeptidase-4 inhibitors will also be reviewed.

Oxidative Stress in Calcific Aortic Valve Stenosis: Protective Role of Natural Antioxidants

Calcific aortic valve stenosis (CAVS) is the most prevalent heart valvular disease worldwide and a slowly progressive disorder characterized by thickening of the aortic valve, calcification, and subsequent heart failure. Valvular calcification is an active cell regulation process in which valvular interstitial cells involve phenotypic conversion into osteoblasts/chondrocytes-like cells. The underlying pathophysiology is complicated, and there have been no pharmacological treatments for CAVS to date. Recent studies have suggested that an increase in oxidative stress is the major trigger of CAVS, and natural antioxidants could ameliorate the detrimental effects of reactive oxygen species in the pathogenesis of CAVS. It is imperative to review the current findings regarding the role of natural antioxidants in CAVS, as they can be a promising therapeutic approach for managing CAVS, a disorder currently without effective treatment. This review summarizes the current findings on molecular mechanisms associated with oxidative stress in the development of valvular calcification and discusses the protective roles of natural antioxidants in the prevention and treatment of CAVS.

Role of oxidative stress in calcific aortic valve disease and its therapeutic implications

Calcific aortic valve disease (CAVD) is the end result of active cellular processes that lead to the progressive fibrosis and calcification of aortic valve leaflets. In western populations, CAVD is a significant cause of cardiovascular morbidity and mortality, and in the absence of effective drugs, it will likely represent an increasing disease burden as populations age. As there are currently no pharmacological therapies available for preventing, treating, or slowing the development of CAVD, understanding the mechanisms underlying the initiation and progression of the disease is important for identifying novel therapeutic targets. Recent evidence has emerged of an important causative role for reactive oxygen species (ROS)-mediated oxidative stress in the pathophysiology of CAVD, inducing the differentiation of valve interstitial cells into myofibroblasts and then osteoblasts. In this review, we focus on the roles and sources of ROS driving CAVD and consider their potential as novel therapeutic targets for this debilitating condition.

Reactive Oxygen Species in Cardiovascular Calcification: Role of Medicinal Plants

Cardiovascular calcification, including vascular calcification and calcific aortic valve disease (CAVD), is a serious worldwide health problem, especially in older adults. The mechanisms underlying cardiovascular calcifications are complex and multifactorial. An increase in reactive oxygen species (ROS) and oxidative stress play important roles in the initiation and development of cardiovascular calcification. This mini-review summarizes the recent evidence that supports the association of ROS with vascular calcification and CAVD and discusses the role of medicinal plants for the prevention and treatment of cardiovascular calcification.

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.

β-Hydroxybutyrate Mitigated Heart Failure with Preserved Ejection Fraction by Increasing Treg Cells via Nox2/GSK-3β

Background

This study was designed to investigate the cardioprotective role of β-hydroxybutyrate (BHB) in heart failure with preserved ejection fraction (HFpEF) and the underlying mechanism.

Methods

A two-hit model with a high-fat diet (HFD) and N^ω-nitrol-arginine methyl ester (L-NAME) was used as an HFpEF model. The treatment group received a weekly intraperitoneal injection of β-hydroxybutyrate (BHB). Cardiac function, inflammation, and fibrosis were evaluated. CD3⁺CD4⁺Foxp3⁺ positive cells within the myocardium were quantified by flow cytometry. The NADPH oxidase 2 (NOX2)/glycogen synthase kinase-3β (GSK3β) pathway was examined by immunoblot analysis.

Results

BHB improved diastolic function, fibrosis and cardiac remodeling in HFpEF. Additionally, BHB inhibited cardiac inflammation and increased cardiac Treg cells, which could be due to the downregulation of the NOX2/GSK-3β pathway.

Conclusion

BHB protected against the progression of HFpEF by increasing cardiac Treg cells by modulating the NOX2/GSK-3β pathway.

The Potential Therapeutic Role of Celastrol in Patients With Heart Failure With Preserved Ejection Fraction

Analysis of left ventricular systolic dysfunction remained at the centre of heart failure research for many years (also known as heart failure with reduced ejection fraction, HFrEF). Although more than 50% of all heart failure patients experience a form of heart failure characterised by preserved ejection fraction (HFpEF), the pathophysiological mechanisms leading to this form of heart failure remain not well-understood. Several evidence-based treatments for HFrEF are in routine use, but there are limited evidence-based therapies for HFpEF. The effects of these remain controversial, with current treatment options being limited to managing the associated symptoms and conditions. Accumulating evidence demonstrates that pro-inflammatory and oxidative stress pathways play key roles in the development and progression of HFpEF, such as the Unfolded Protein Response (UPR) and inducible nitric oxide synthase. Celastrol, derived from medicinal plants, is a bioactive compound with strong anti-inflammatory properties, which could deem it as fruitful in overcoming the effects of such dysregulated UPR. This literature review therefore focuses on Celastrol's anti-inflammatory and antioxidant activities, alongside its other potential therapeutic activities, and its ability to impede the pathways that are thought to be involved in the development of HFpEF, such as the JAK2/STAT pathway, to elucidate the potential therapeutic role of this bioactive compound, in the treatment of HFpEF.

Up-regulation of heme oxygenase-1 by celastrol alleviates oxidative stress and vascular calcification in chronic kidney disease

Vascular calcification is very commonly observed in patients with chronic kidney disease (CKD), but there is no efficient therapy available. Oxidative stress plays critical roles in the progression of vascular calcification. Celastrol (Cel), a natural constituent derived from Chinese herbals, exhibits anti-oxidative stress activity. Here, we investigated the effect of celastrol on vascular calcification using vascular smooth muscle cells (VSMCs), arterial rings and CKD rats. Alizarin red staining and gene expression analysis showed that Cel dose-dependently inhibited rat VSMC calcification and osteogenic differentiation. Similarly, ex vivo study revealed that Cel inhibited calcification of rat and human arterial rings. In addition, micro-computed tomography, alizarin red staining and calcium content analysis confirmed that Cel inhibited aortic calcification in CKD rats. Interestingly, Cel treatment increased the mRNA and protein levels of heme oxygenase-1 (HMOX-1), and reduced the levels of reactive oxygen species (ROS) in VSMCs. Furthermore, both pharmacological inhibition of HMOX-1 and knockdown of HMOX-1 by siRNA independently counteracted the inhibitory effect of Cel on vascular calcification. Moreover, knockdown of HMOX-1 prevented Cel treatment-mediated reduction in ROS levels. Finally, Cel treatment reduced Vitamin D3-induced aortic calcification in mice and this effect was blocked by HMOX-1 inhibitor ZnPP9. Collectively, our results suggest that up-regulation of HMOX-1 is required for the inhibitory effect of Cel on vascular calcification. Modulation of HMOX-1 may provide a novel strategy for the treatment of vascular calcification in CKD.

Inflammatory and Biomechanical Drivers of Endothelial-Interstitial Interactions in Calcific Aortic Valve Disease

Calcific aortic valve disease is dramatically increasing in global burden, yet no therapy exists outside of prosthetic replacement. The increasing proportion of younger and more active patients mandates alternative therapies. Studies suggest a window of opportunity for biologically based diagnostics and therapeutics to alleviate or delay calcific aortic valve disease progression. Advancement, however, has been hampered by limited understanding of the complex mechanisms driving calcific aortic valve disease initiation and progression towards clinically relevant interventions.

Current Evidence and Future Perspectives on Pharmacological Treatment of Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS), the most common heart valve disease, is characterized by the slow progressive fibro-calcific remodeling of the valve leaflets, leading to progressive obstruction to the blood flow. CAVS is an increasing health care burden and the development of an effective medical treatment is a major medical need. To date, no effective pharmacological therapies have proven to halt or delay its progression to the severe symptomatic stage and aortic valve replacement represents the only available option to improve clinical outcomes and to increase survival. In the present report, the current knowledge and latest advances in the medical management of patients with CAVS are summarized, placing emphasis on lipid-lowering agents, vasoactive drugs, and anti-calcific treatments. In addition, novel potential therapeutic targets recently identified and currently under investigation are reported.

Glycogen synthase kinase-3β: a promising candidate in the fight against fibrosis

Fibrosis exists in almost all organs/tissues of the human body, plays an important role in the occurrence and development of diseases and is also a hallmark of the aging process. However, there is no effective prevention or therapeutic method for fibrogenesis. As a serine/threonine (Ser/Thr)-protein kinase, glycogen synthase kinase-3β (GSK-3β) is a vital signaling mediator that participates in a variety of biological events and can inhibit extracellular matrix (ECM) accumulation and the epithelial-mesenchymal transition (EMT) process, thereby exerting its protective role against the fibrosis of various organs/tissues, including the heart, lung, liver, and kidney. Moreover, we further present the upstream regulators and downstream effectors of the GSK-3β pathway during fibrosis and comprehensively summarize the roles of GSK-3β in the regulation of fibrosis and provide several potential targets for research. Collectively, the information reviewed here highlights recent advances vital for experimental research and clinical development, illuminating the possibility of GSK-3β as a novel therapeutic target for the management of tissue fibrosis in the future.

Attenuating Effects of Pyrogallol-Phloroglucinol-6,6-Bieckol on Vascular Smooth Muscle Cell Phenotype Changes to Osteoblastic Cells and Vascular Calcification Induced by High Fat Diet

Advanced glycation end products/receptor for AGEs (AGEs/RAGEs) or Toll like receptor 4 (TLR4) induce vascular smooth muscle cell (VSMC) phenotype changes in osteoblast-like cells and vascular calcification. We analyzed the effect of Ecklonia cava extract (ECE) or pyrogallol-phloroglucinol-6,6-bieckol (PPB) on VSMC phenotype changes and vascular calcification prompted by a high-fat diet (HFD). HFD unregulated RAGE, TLR4, transforming growth factor beta (TGFβ), bone morphogenetic protein 2 (BMP2), protein kinase C (PKC), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signals in the aorta of mice. ECE and PPB restored the increase of those signal pathways. AGE- or palmitate-treated VSMC indicated similar changes with the animal. HFD increased osteoblast-like VSMC, which was evaluated by measuring core-binding factor alpha-1 (CBFα-1) and osteocalcin expression and alkaline phosphatase (ALP) activity in the aorta. ECE and PPB reduced vascular calcification, which was analyzed by the calcium deposition ratio, and Alizarin red S stain was increased by HFD. PPB and ECE reduced systolic, diastolic, and mean blood pressure, which increased by HFD. PPB and ECE reduced the phenotype changes of VSMC to osteoblast-like cells and vascular calcification and therefore lowered the blood pressure.