Metformin, resveratrol, and exendin-4 inhibit high phosphate-induced vascular calcification via AMPK-RANKL signaling

The crosstalks between vascular endothelial cells, vascular smooth muscle cells, and adventitial fibroblasts in vascular remodeling

Pathological vascular remodeling (VR) is characterized by structural and functional alterations in the vascular wall resulting from injury, which significantly contribute to the development of cardiovascular diseases (CVDs). The vascular wall consists primarily of endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and adventitial fibroblasts (AFs), whose interactions are crucial for both the formation of the vascular system and the maintenance of mature blood vessels. Disruptions in the communication between these cell types have been implicated in the progression of VR. This review examines the complex interactions between ECs, VSMCs, and AFs in the context of CVD development, emphasizing a relatively underexplored yet potentially critical mechanism. This interaction framework likely extends to the broader cellular dialogue in the pathogenesis of CVDs, suggesting novel therapeutic strategies for intervention.

Nitrogen-containing bisphosphonate induces enhancement of OPG expression and inhibition of RANKL expression via inhibition of farnesyl pyrophosphate synthase to inhibit the osteogenic differentiation and calcification in vascular smooth muscle cells

BACKGROUND

Nitrogen-containing bisphosphonate(N-BP)had been found to inhibit the osteogenic differentiation and calcification in vascular smooth muscle cells (VSMCs), but the mechanism is not clear. We intend to verify that N-BP induces enhancement of OPG expression and inhibition of RANKL expression via inhibition of farnesyl pyrophosphate synthase(FPPS) to inhibit the osteogenic differentiation and calcification in VSMCs.

METHODS

β-glycerophosphate (β-GP) was used to induce the osteogenic differentiation and calcification in VSMCs. VSMCs were treated with N-BP or pretreated with downstream products of farnesyl pyrophosphate synthase(FPPS) in mevalonate pathway, such as farnesol (FOH) or geranylgeraniol (GGOH). Alizarin red S staining and determination of calcium content were used to detect calcium deposition.Western Blotting were used to detect expressions of proteins(OPG and RANKL ) and osteogenic marker proteins (Runx2 and OPN).

RESULTS

β-GP induced the osteogenic differentiation and calcification in VSMCs, increased RANKL protein expression and had no significant effect on OPG protein expression. With the treatment of N-BP, the expression of OPG protein was increased and expression of RANKL protein was decreased in VSMCs undergoing osteogenic differentiation and calcification. In addition, N-BP reduced the osteogenic marker proteins (Runx2 and OPN) expression and calcium deposition in VSMCs undergoing osteogenic differentiation and calcification. These effects of N-BP on the osteogenic differentiation and calcification in VSMCs were concentration-dependent, which could be reversed by the downstream products of FPPS, such as FOH or GGOH.

CONCLUSION

N-BP increases OPG expression and decreases RANKL expression via inhibition of FPPS to inhibit the osteogenic differentiation and calcification in VSMCs.

Exploring the Potential of Ribes nigrum L., Aronia melanocarpa (Michx.) Elliott, and Sambucus nigra L. Fruit Polyphenol-Rich Composition and Metformin Synergy in Type 2 Diabetes Management

Type 2 diabetes, characterized by insulin resistance and impaired glucose homeostasis, is commonly managed through lifestyle interventions and medications such as metformin. Although metformin is generally well-tolerated, it may cause gastrointestinal adverse effects and, in rare cases, precipitate lactic acidosis, necessitating cautious use in individuals with renal dysfunction. Additionally, concerns regarding its impact on hepatic function have led to its discontinuation in cirrhotic patients. This study explores the potential synergistic benefits of a polyphenol-rich blend containing black currant, chokeberry, and black elderberry extracts alongside metformin in managing type 2 diabetes. In vitro results highlighted distinct effects of AMPK pathway modulation, showcasing reductions in cholesterol and triglyceride levels alongside a notable enhancement in glucose uptake. The blend, when combined with metformin, significantly reduced insulin levels and fasting glucose concentrations in an in vivo model. Furthermore, hepatic analyses unveiled a modulation in cellular pathways, suggesting a potential influence on lipid metabolism, attenuation of inflammatory pathways, a decrease in cellular stress response, and antioxidant defense mechanisms, collectively implying a potential reduction in liver fat accumulation. The findings suggest a potential complementary role of polyphenols in enhancing the efficacy of metformin, possibly allowing for reduced metformin dosage and mitigating its side effects. Further clinical studies are warranted to validate these findings and establish the safety and efficacy of this nutraceutical approach in managing type 2 diabetes.

The Role of the Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin Ratio in Vascular Diseases: A Therapeutic Approach

Cardiovascular and bone diseases contribute independently to mortality and global health. The exact mechanisms involved in the pathophysiology shared between bone and vascular diseases are not well defined. Endothelial cells and osteoblasts communicate during osteogenesis, thus establishing a connection between angiogenesis and osteogenesis. One shared mechanism may involve osteoprotegerin (OPG) and its ligand Receptor Activator of NF-κB Ligand (RANKL). The RANKL/OPG ratio is an important modulator for the skeletal, immunological, and vascular systems. OPG levels are elevated due to either osteogenic causes or inflammatory responses in the vasculature. The data obtained from clinical and in vitro studies support the role of the RANKL/OPG ratio as a potential marker for the progression of endothelial damage. Therefore, determining the therapeutic approaches for the targeting RANKL/OPG ratio and evaluating its usage as a biomarker in cardiovascular and bone pathophysiology are needed. By integrating the protective and disease-causing role of OPG with its ligand, this review outlines the role of the RANKL/OPG ratio at the molecular level. We also consider targeted therapeutic approaches.

Glucagon-Like Peptide Receptor Agonist Inhibits Angiotensin II-Induced Proliferation and Migration in Vascular Smooth Muscle Cells and Ameliorates Phosphate-Induced Vascular Smooth Muscle Cells Calcification

BACKGRUOUND

Glucagon-like peptide-1 receptor agonist (GLP-1RA), which is a therapeutic agent for the treatment of type 2 diabetes mellitus, has a beneficial effect on the cardiovascular system.

METHODS

To examine the protective effects of GLP-1RAs on proliferation and migration of vascular smooth muscle cells (VSMCs), A-10 cells exposed to angiotensin II (Ang II) were treated with either exendin-4, liraglutide, or dulaglutide. To examine the effects of GLP-1RAs on vascular calcification, cells exposed to high concentration of inorganic phosphate (Pi) were treated with exendin-4, liraglutide, or dulaglutide.

RESULTS

Ang II increased proliferation and migration of VSMCs, gene expression levels of Ang II receptors AT1 and AT2, proliferation marker of proliferation Ki-67 (Mki-67), proliferating cell nuclear antigen (Pcna), and cyclin D1 (Ccnd1), and the protein expression levels of phospho-extracellular signal-regulated kinase (p-Erk), phospho-c-JUN N-terminal kinase (p-JNK), and phospho-phosphatidylinositol 3-kinase (p-Pi3k). Exendin-4, liraglutide, and dulaglutide significantly decreased the proliferation and migration of VSMCs, the gene expression levels of Pcna, and the protein expression levels of p-Erk and p-JNK in the Ang II-treated VSMCs. Erk inhibitor PD98059 and JNK inhibitor SP600125 decreased the protein expression levels of Pcna and Ccnd1 and proliferation of VSMCs. Inhibition of GLP-1R by siRNA reversed the reduction of the protein expression levels of p-Erk and p-JNK by exendin-4, liraglutide, and dulaglutide in the Ang II-treated VSMCs. Moreover, GLP-1 (9-36) amide also decreased the proliferation and migration of the Ang II-treated VSMCs. In addition, these GLP-1RAs decreased calcium deposition by inhibiting activating transcription factor 4 (Atf4) in Pi-treated VSMCs.

CONCLUSION

These data show that GLP-1RAs ameliorate aberrant proliferation and migration in VSMCs through both GLP-1Rdependent and independent pathways and inhibit Pi-induced vascular calcification.

Wogonin inhibits oxidative stress and vascular calcification via modulation of heme oxygenase-1

Vascular calcification (VC) is highly prevalent and increases the morbidity and mortality of cardiovascular diseases. However, the underlying mechanism remains unclear and there is no effective treatment so far. Interestingly, using systems pharmacology approach, we have predicted that Wogonin (Wog) exhibited potential activity against VC. Then we validated the effect of Wog on VC using human and rat vascular smooth muscle cells (VSMCs), rat arterial rings and vitamin D3-overloaded mouse models. Our results showed that Wog dose-dependently inhibited calcification of VSMCs and rat arterial rings. Consistently, alizarin red staining and calcium content assay confirmed that Wog inhibited aortic calcification in vitamin D3-overloaded mice. Moreover, by constructing the protein regulating network of Wog in suppressing VC, we found heme oxygenase-1 (HMOX-1) was regulated by Wog. Additionally, pathway enrichment analysis revealed that inhibition of reactive oxygen species (ROS) pathway participated in the inhibitory role of Wog in VC and HMOX-1 was also involved in this process. Notably, our study revealed that Wog treatment promoted HMOX-1 expression, and reduced ROS levels in VSMCs. Interestingly, both inhibition of HMOX-1 by ZnPP9 and knockdown of HMOX-1 by siRNA independently eliminated the inhibitory effect of Wog on VC. Finally, administration of Wog suppressed aortic calcification in vitamin D3-overloaded mice and this effect was counteracted by ZnPP9,suggesting the crucial role of HMOX-1 in the inhibitory effect of Wog on VC. Collectively, this study combines systems pharmacology-based strategy and experiments to identify the therapeutic potential of Wog for VC via upregulating HMOX-1 and reducing oxidative stress.

DMU-212 against EGFR-mutant non-small cell lung cancer via AMPK/PI3K/Erk signaling pathway

Although some important advances have been achieved in clinical and diagnosis in the past few years, the management of non-small cell lung cancer (NSCLC) is ultimately dissatisfactory due to the low overall cure and survival rates. Epidermal growth factor (EGFR) has been recognized as a carcinogenic driver and is a crucial pharmacological target for NSCLC. DMU-212, an analog of resveratrol, has been reported to have significant inhibitory effects on several types of cancer. However, the effect of DMU-212 on lung cancer remains unclear. Therefore, this study aims to determine the effects and underlying mechanism of DMU-212 on EGFR-mutant NSCLC cells. The data found that the cytotoxicity of DMU-212 on three EGFR-mutant NSCLC cell lines was significantly higher than that of normal lung epithelial cell. Further study showed that DMU-212 can regulate the expression of cell cycle-related proteins including p21 and cyclin B1 to induce G2/M phase arrest in both H1975 and PC9 cells. Moreover, treatment with DMU-212 significantly promoted the activation of AMPK and simultaneously down-regulated the expression of EGFR and the phosphorylation of PI3K, Akt and ERK. In conclusion, our study suggested that DMU-212 inhibited the growth of NSCLCs via targeting of AMPK and EGFR.

Indoxyl-sulfate activation of the AhR- NF-κB pathway promotes interleukin-6 secretion and the subsequent osteogenic differentiation of human valvular interstitial cells from the aortic valve

BACKGROUND

Calcific aortic stenosis (CAS) is more prevalent, occurs earlier, progresses faster and has worse outcomes in patients with chronic kidney disease (CKD). The uremic toxin indoxyl sulfate (IS) is powerful predictor of cardiovascular mortality in these patients and a strong promoter of ectopic calcification whose role in CAS remains poorly studied. The objective of this study was to evaluate whether IS influences the mineralization of primary human valvular interstitial cells (hVICs) from the aortic valve.

METHODS

Primary hVICs were exposed to increasing concentrations of IS in osteogenic medium (OM). The hVICs' osteogenic transition was monitored by qRT-PCRs for BMP2 and RUNX2 mRNA. Cell mineralization was assayed using the o-cresolphthalein complexone method. Inflammation was assessed by monitoring NF-κB activation using Western blots as well as IL-1β, IL-6 and TNF-α secretion by ELISAs. Small interfering RNA (siRNA) approaches enabled us to determine which signaling pathways were involved.

RESULTS

Indoxyl-sulfate increased OM-induced hVICs osteogenic transition and calcification in a concentration-dependent manner. This effect was blocked by silencing the receptor for IS (the aryl hydrocarbon receptor, AhR). Exposure to IS promoted p65 phosphorylation, the blockade of which inhibited IS-induced mineralization. Exposure to IS promoted IL-6 secretion by hVICs, a phenomenon blocked by silencing AhR or p65. Incubation with an anti-IL-6 antibody neutralized IS's pro-calcific effects.

CONCLUSION

IS promotes hVIC mineralization through AhR-dependent activation of the NF-κB pathway and the subsequent release of IL-6. Further research should seek to determine whether targeting inflammatory pathways can reduce the onset and progression of CKD-related CAS.

The Regulation of the AMPK/mTOR Axis Mitigates Tendon Stem/Progenitor Cell Senescence and Delays Tendon Aging

Age-related tendon disorders are closely linked with tendon stem/progenitor cell (TSPC) senescence. However, the underlying mechanisms of TSPC senescence and promising therapeutic strategies for rejuvenation of TSPC senescence remain unclear. In this study, the senescent state of TSPCs increased with age. It was also verified that the AMPK inhibition/mTOR activation is correlated with the senescent state of TSPCs. Furthermore, a low dose of metformin mitigated TSPC senescence and restored senescence-related functions, including proliferation, colony-forming ability, migration ability and tenogenic differentiation ability at the early stage of aging. The protective effects of metformin on TSPCs were regulated through the AMPK/mTOR axis. An in vivo study showed that metformin treatment postpones tendon aging and enhances AMPK phosphorylation but reduces mTOR phosphorylation in a natural aging rat model. Our study revealed new insight and mechanistic exploration of TSPC senescence and proposed a novel therapeutic treatment for age-related tendon disorders by targeting the AMPK/mTOR axis at the early stage of aging.

Vascular calcification: Molecular mechanisms and therapeutic interventions

Vascular calcification (VC) is recognized as a pathological vascular disorder associated with various diseases, such as atherosclerosis, hypertension, aortic valve stenosis, coronary artery disease, diabetes mellitus, as well as chronic kidney disease. Therefore, it is a life-threatening state for human health. There were several studies targeting mechanisms of VC that revealed the importance of vascular smooth muscle cells transdifferentiating, phosphorous and calcium milieu, as well as matrix vesicles on the progress of VC. However, the underlying molecular mechanisms of VC need to be elucidated. Though there is no acknowledged effective therapeutic strategy to reverse or cure VC clinically, recent evidence has proved that VC is not a passive irreversible comorbidity but an active process regulated by many factors. Some available approaches targeting the underlying molecular mechanism provide promising prospects for the therapy of VC. This review aims to summarize the novel findings on molecular mechanisms and therapeutic interventions of VC, including the role of inflammatory responses, endoplasmic reticulum stress, mitochondrial dysfunction, iron homeostasis, metabolic imbalance, and some related signaling pathways on VC progression. We also conclude some recent studies on controversial interventions in the clinical practice of VC, such as calcium channel blockers, renin-angiotensin system inhibitions, statins, bisphosphonates, denosumab, vitamins, and ion conditioning agents.

Role of endothelial cells in vascular calcification

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

Resveratrol ameliorates high-phosphate-induced VSMCs to osteoblast-like cells transdifferentiation and arterial medial calcification in CKD through regulating Wnt/β-catenin signaling

Vascular smooth muscle cells (VSMCs) to osteoblast-like cells transdifferentiation induced by high-phosphate is a crucial step in the development of arterial medial calcification (AMC) in patients with chronic kidney disease (CKD), and previous studies implicate Wnt/β-catenin signaling in osteogenic transdifferentiation of VSMCs and AMC. Given that resveratrol's ability to modulate Wnt/β-catenin signaling in other types of cell, we tested the effect of resveratrol on high-phosphate-induced osteogenic transdifferentiation of VSMCs and AMC in CKD. Resveratrol ameliorated AMC in rats with chronic renal failure and calcium deposition in aortic rings and VSMCs cultured in a high-phosphate environment. Resveratrol also diminished high-phosphate-induced osteogenic transdifferentiation of VSMCs in cultured aortic rings and VSMCs. In vitro, resveratrol attenuated the activation of β-catenin induced by high-phosphate and inhibited the expression of Runx2, a downstream effector of Wnt/β-catenin signaling during osteogenic transdifferentiation of VSMCs. Intriguingly, resveratrol inhibited high-phosphate-induced phosphorylation of LRP6 (Ser1490), but didn't inhibit Wnt3a-induced phosphorylation of LRP6 (Ser1490) and Runx2 expression. The expression of several Wnts was induced by high-phosphate, but the expression of Wnt7a, not Wnt2b and Wnt10a could be suppressed by resveratrol. In addition, the expression of both porcupine and wntless, two obligatory proteins for Wnt secretion, was induced by high-phosphate in cultured aortic rings and VSMCs, which could be suppressed by resveratrol. In summary, these findings suggest that resveratrol possesses a vascular protective effect on retarding high-phosphate-induced osteogenic transdifferentiation of VSMCs and AMC in CKD by targeting Wnt/β-catenin signaling, which may, to a large extent, via impeding Wnt secretion.

BGP-15 Inhibits Hyperglycemia-Aggravated VSMC Calcification Induced by High Phosphate

Vascular calcification associated with high plasma phosphate (Pi) level is a frequent complication of hyperglycemia, diabetes mellitus, and chronic kidney disease. BGP-15 is an emerging anti-diabetic drug candidate. This study was aimed to explore whether BGP-15 inhibits high Pi-induced calcification of human vascular smooth muscle cells (VSMCs) under normal glucose (NG) and high glucose (HG) conditions. Exposure of VSMCs to Pi resulted in accumulation of extracellular calcium, elevated cellular Pi uptake and intracellular pyruvate dehydrogenase kinase-4 (PDK-4) level, loss of smooth muscle cell markers (ACTA, TAGLN), and enhanced osteochondrogenic gene expression (KLF-5, Msx-2, Sp7, BMP-2). Increased Annexin A2 and decreased matrix Gla protein (MGP) content were found in extracellular vesicles (EVs). The HG condition markedly aggravated Pi-induced VSMC calcification. BGP-15 inhibited Pi uptake and PDK-4 expression that was accompanied by the decreased nuclear translocation of KLF-5, Msx-2, Sp7, retained VSMC markers (ACTA, TAGLN), and decreased BMP-2 in both NG and HG conditions. EVs exhibited increased MGP content and decreased Annexin A2. Importantly, BGP-15 prevented the deposition of calcium in the extracellular matrix. In conclusion, BGP-15 inhibits Pi-induced osteochondrogenic phenotypic switch and mineralization of VSMCs in vitro that make BGP-15 an ideal candidate to attenuate both diabetic and non-diabetic vascular calcification.

GLP-1 receptor agonists (GLP-1RAs): cardiovascular actions and therapeutic potential

Type 2 diabetes mellitus (T2DM) is closely associated with cardiovascular diseases (CVD), including atherosclerosis, hypertension and heart failure. Some anti-diabetic medications are linked with an increased risk of weight gain or hypoglycemia which may reduce the efficacy of the intended anti-hyperglycemic effects of these therapies. The recently developed receptor agonists for glucagon-like peptide-1 (GLP-1RAs), stimulate insulin secretion and reduce glycated hemoglobin levels without having side effects such as weight gain and hypoglycemia. In addition, GLP1-RAs demonstrate numerous cardiovascular protective effects in subjects with or without diabetes. There have been several cardiovascular outcomes trials (CVOTs) involving GLP-1RAs, which have supported the overall cardiovascular benefits of these drugs. GLP1-RAs lower plasma lipid levels and lower blood pressure (BP), both of which contribute to a reduction of atherosclerosis and reduced CVD. GLP-1R is expressed in multiple cardiovascular cell types such as monocyte/macrophages, smooth muscle cells, endothelial cells, and cardiomyocytes. Recent studies have indicated that the protective properties against endothelial dysfunction, anti-inflammatory effects on macrophages and the anti-proliferative action on smooth muscle cells may contribute to atheroprotection through GLP-1R signaling. In the present review, we describe the cardiovascular effects and underlying molecular mechanisms of action of GLP-1RAs in CVOTs, animal models and cultured cells, and address how these findings have transformed our understanding of the pharmacotherapy of T2DM and the prevention of CVD.

Metformin attenuates hyperlipidaemia-associated vascular calcification through anti-ferroptotic effects

Ferroptosis is a form of regulated cell death that involves metabolic dysfunction resulting from iron-dependent excessive lipid peroxidation. Elevated plasma levels of free fatty acids are tightly associated with cardiometabolic risk factors in patients with obesity, diabetes mellitus, and metabolic syndrome. Metformin (Met) is an antidiabetic drug with beneficial cardiovascular disease effects. The aim of this study was to determine the effects of Met on ferroptosis induced by lipid overload and the effects of these changes on vascular smooth muscle cells (VSMCs) calcification. We developed a hyperlipidaemia-related vascular calcification in vivo model with rats fed a high-fat diet combined with vitamin D3 plus nicotine, and palmitic acid (PA), the most abundant long-chain saturated fatty acid in plasma, was used to induce lipid overload and develop an oxidative stress-related calcification model in vitro. The results showed that Met inhibits hyperlipidaemia-associated calcium deposition in the rat aortic tissue. In vitro, treatment of VSMCs with PA stimulates ferroptosis concomitant with increased calcium deposition in VSMCs, while pretreatment with Met attenuates these effects. Furthermore, PA also promotes the protein expression of the extracellular matrix protein periostin (POSTN) and its secretion into the extracellular environment. More importantly, upregulation of POSTN increased the sensitivity of cells to ferroptosis. Mechanistically, upregulation of POSTN suppresses SLC7A11 expression through the inhibition of p53 in VSMCs, which contributes to a decrease in glutathione synthesis and therefore triggers ferroptosis. Interestingly, overexpression of p53 attenuates the inhibitory effect of POSTN on SLC7A11 expression, accompanied by increased Gpx4 expression. Furthermore, p53 knockdown suppresses Met-mediated anti-ferroptosis effects in PA-treated VSMCs, which may be related to the downregulation of SLC7A11 expression. In addition, supplementation of VSMCs with Met enhances the antioxidative capacity of VSMCs through Nrf2 signalling activation. Collectively, targeting POSTN in VSMCs may provide a new strategy for vascular calcification prevention or treatment.