Downregulation of HDAC9 by the ketone metabolite β-hydroxybutyrate suppresses vascular calcification

Histone deacetylase 9 promotes osteogenic trans-differentiation of vascular smooth muscle cells via ferroptosis in chronic kidney disease vascular calcification

Vascular calcification, a common complication of chronic kidney disease (CKD), remains an unmet therapeutic challenge. The trans-differentiation of vascular smooth muscle cells (VSMCs) into osteoblast-like cells is crucial in the pathogenesis of vascular calcification in CKD. Despite ferroptosis promotes vascular calcification in CKD, the upstream or downstream regulatory mechanisms involved remains unclear. In this study, we aimed to investigate the regulatory mechanism involved in ferroptosis in CKD vascular calcification. Transcriptome sequencing revealed a potential relationship between HDAC9 and ferroptosis in CKD vascular calcification. Subsequently, we observed increased expression of HDAC9 in calcified arteries of patients undergoing hemodialysis and in a rat model of CKD. We further demonstrated that knockout of HDAC9 attenuates osteogenic trans-differentiation and ferroptosis in VSMCs stimulated by high calcium and phosphorus. In addition, RSL3 exacerbated ferroptosis and osteogenic trans-differentiation of VSMCs exposed to high levels of calcium and phosphorus, and these effects were suppressed to some extent by HDAC9 knockout. In summary, our findings suggest that HDAC9 promotes VSMCs osteogenic trans-differentiation involving ferroptosis, providing new insights for the therapy of CKD vascular calcification.

Role of the histone deacetylase family in lipid metabolism: Structural specificity and functional diversity

Lipids play crucial roles in signal transduction. Lipid metabolism is associated with several transcriptional regulators, including peroxisome proliferator activated receptor γ, sterol regulatory element-binding protein 1, and acetyl-CoA carboxylase. In recent years, increasing evidence has suggested that members of the histone deacetylase (HDAC) family play key roles in lipid metabolism. However, the mechanisms by which each member of this family regulates lipid metabolism remain unclear. This review discusses the latest research on the roles played by HDACs in fat metabolism. The role of HDACs in obesity, diabetes, and atherosclerosis has also been discussed. In addition, the interaction of HDACs with the gut microbiome and circadian rhythm has been reviewed, and the future development trend in HDACs has been predicted, which may potentiate therapeutic application of targeted HDACs in related metabolic diseases.

Pathogenesis of Sarcopenia in Chronic Kidney Disease-The Role of Inflammation, Metabolic Dysregulation, Gut Dysbiosis, and microRNA

Chronic kidney disease (CKD) is a progressive disorder associated with a decline in kidney function. Consequently, patients with advanced stages of CKD require renal replacement therapies, such as dialysis and kidney transplantation. Various conditions lead to the development of CKD, including diabetes mellitus, hypertension, and glomerulonephritis, among others. The disease is associated with metabolic and hormonal dysregulation, including uraemia and hyperparathyroidism, as well as with low-grade systemic inflammation. Altered homeostasis increases the risk of developing severe comorbidities, such as cardiovascular diseases or sarcopenia, which increase mortality. Sarcopenia is defined as a progressive decline in muscle mass and function. However, the precise mechanisms that link CKD and the development of sarcopenia are poorly understood. Knowledge about these linking mechanisms might lead to the introduction of precise treatment strategies that could prevent muscle wasting. This review discusses inflammatory mediators, metabolic and hormonal dysregulation, gut microbiota dysbiosis, and non-coding RNA alterations that could link CKD and sarcopenia.

β-hydroxybutyrate and ischemic stroke: roles and mechanisms

Stroke is a significant global burden, causing extensive morbidity and mortality. In metabolic states where glucose is limited, ketone bodies, predominantly β-hydroxybutyrate (BHB), act as alternative fuel sources. Elevated levels of BHB have been found in the ischemic hemispheres of animal models of stroke, supporting its role in the pathophysiology of cerebral ischemia. Clinically, higher serum and urinary BHB concentrations have been associated with adverse outcomes in ischemic stroke, highlighting its potential utility as a prognostic biomarker. In both animal and cellular models, exogenous BHB administration has exhibited neuroprotective effects, reduction of infarct size, and improvement of neurological outcomes. In this review, we focus on the role of BHB before and after ischemic stroke, with an emphasis on the therapeutic potential and mechanisms of ketone administration after ischemic stroke.

Ethanolic extract of Arctium lappa leaves alleviates cerebral ischemia reperfusion-induced inflammatory injury via HDAC9-mediated NF-κB pathway

BACKGROUND

Ischemic stroke (IS) is a major cause of mortality and disability worldwide. Inflammatory response is crucial in the pathogenesis of tissue injury in cerebral infarction. Arctium lappa leaves are traditionally used to treat IS.

PURPOSES

To investigate the neuroprotective effects and molecular mechanisms of the ethanolic extract of A. lappa leaves (ALLEE) on cerebral ischemia-reperfusion (CIR).

METHODS

Middle cerebral artery obstruction reperfusion (MCAO/R) rats and an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model were used to evaluate ALLEE pharmacodynamics. Various methods, including neurological function, 2,3,5-triphenyltetrazolium chloride, hematoxylin and eosin, and Nissl, enzyme-linked immunosorbent, and TdT-mediated dUTP nick-end labeling assays, were used to analyze the neuroprotective effects of ALLEE in vitro and in vivo. The major chemical components and potential target genes of ALLEE were screened using network pharmacology. Molecular docking, western blotting, and immunofluorescence analyses were performed to confirm the effectiveness of the targets in related pathways.

RESULTS

ALLEE exerted potent effects on the MCAO/R model by decreasing the neurological scores, infarct volumes, and pathological features (p < 0.01). Furthermore, network pharmacology results revealed that the treatment of IS with ALLEE involved the regulation of various inflammatory pathways, such as the tumor necrosis factor (TNF) and chemokine signaling pathways. ALLEE also played key roles in targeting key molecules, including nuclear factor (NF)-κBIA, NF-κB1, interleukin (IL)-6, TNF-α and IL1β, and regulating the histone deacetylase (HDAC)-9-mediated signaling pathway. In vivo and in vitro analyses revealed that ALLEE significantly regulated the NF-κB pathway, promoted the phosphorylation activation of NF-κB P65, IκB and IKK (p < 0.01 or p < 0.05), and decreased the expression levels of the inflammatory factors, IL-1β, IL-6 and TNF-α (p < 0.01). Moreover, ALLEE significantly decreased the expression of HDAC9 (p < 0.01) that is associated with inflammatory responses. However, HDAC9 overexpression partially reversed the neuroprotective effects of ALLEE and its suppressive effects on inflammation and phosphorylation of NF-κB (p < 0.01).

CONCLUSIONS

In conclusion, our results revealed that ALLEE ameliorates MCAO/R-induced experimental CIR by modulating inflammatory responses via the inhibition of HDAC9-mediated NF-κB pathway.

Effects of Different Carbohydrate Content Diet on Gut Microbiota and Aortic Calcification in Diabetic Mice

Introduction

Vascular calcification is a major cause of cardiovascular accidents in patients with type 2 diabetes mellitus. This study aimed to investigate the impact of carbohydrates on gut microbiota and aortic calcification in diabetic ApoE-/- mice.

Methods

The diabetic ApoE-/- mice were randomly divided into 4 groups: ketogenic diet group, low carbohydrate diet group, medium carbohydrate diet group, and high carbohydrate diet group. The mice were fed continuously for 6 months, with blood glucose, blood ketone and body weight monitored monthly. Lipid metabolism indicators and inflammatory factors were detected using ELISA. The intestinal barrier, atherosclerotic lesion areas, and vascular calcifications were analyzed based on their morphology. Gut microbiota was analyzed using 16S rRNA genes.

Results

We found that ketogenic diet played some roles improving glucose, lipid metabolism, and inflammation. Ketogenic diet could improve the intestinal barrier to some extent and increase intestinal bacteria. Compared to the other three groups, the relative abundance of genus Allobaculum, species Blautia producta and Clostridium Ramosum in the ketogenic diet group was significantly increased (P <0.05), which has protective effects in diabetic ApoE-/- mice.

Conclusion

Ketogenic diet could delay the onset of aortic atherosclerosis, aortic calcification and improve intestinal barrier function in diabetic ApoE-/- mice.

Oxidized phospholipid POVPC contributes to vascular calcification by triggering ferroptosis of vascular smooth muscle cells

Vascular calcification is an actively regulated biological process resembling bone formation, and osteogenic differentiation of vascular smooth muscle cells (VSMCs) plays a crucial role in this process. 1-Palmitoyl-2-(5'-oxo-valeroyl)-sn-glycero-3-phosphocholine (POVPC), an oxidized phospholipid, is found in atherosclerotic plaques and has been shown to induce oxidative stress. However, the effects of POVPC on osteogenic differentiation and calcification of VSMCs have yet to be studied. In the present study, we investigated the role of POVPC in vascular calcification using in vitro and ex vivo models. POVPC increased mineralization of VSMCs and arterial rings, as shown by alizarin red staining. In addition, POVPC treatment increased expression of osteogenic markers Runx2 and BMP2, indicating that POVPC promotes osteogenic transition of VSMCs. Moreover, POVPC increased oxidative stress and impaired mitochondria function of VSMCs, as shown by increased ROS levels, impairment of mitochondrial membrane potential, and decreased ATP levels. Notably, ferroptosis triggered by POVPC was confirmed by increased levels of intracellular ROS, lipid ROS, and MDA, which were decreased by ferrostatin-1, a ferroptosis inhibitor. Furthermore, ferrostatin-1 attenuated POVPC-induced calcification of VSMCs. Taken together, our study for the first time demonstrates that POVPC promotes vascular calcification via activation of VSMC ferroptosis. Reducing the levels of POVPC or inhibiting ferroptosis might provide a novel strategy to treat vascular calcification.

Potential actions of capsaicin for preventing vascular calcification of vascular smooth muscle cells in vitro and in vivo

Vascular calcification (VC) is an accurate risk factor and predictor of adverse cardiovascular events; however, there is currently no effective therapy to specifically prevent VC progression. Capsaicin (Cap) is a bioactive alkaloid isolated from Capsicum annuum L., a traditional medicinal and edible plant that is beneficial for preventing cardiovascular diseases. However, the effect of Cap on VC remains unclear. This study aimed to explore the effects and related mechanisms of Cap on aortic calcification in a mouse and on Pi-induced calcification in vascular smooth muscle cells (VSMCs). First, we established a calcification mouse model with vitamin D3 and evaluated the effects of Cap on calcification mice using von Kossa staining, calcium content, and alkaline phosphatase activity tests. The results showed that Cap significantly improved calcification in mice. VSMCs were then cultured in 2.6 mM Na2HPO4 and 50 μg/mL ascorbic acid for 7 days to obtain a calcification model, and we investigated the effects and mechanisms of Cap on VSMCs calcification by assessing the changes of calcium deposition, calcium content, and subsequent VC biomarkers. These results showed that Cap alleviated VSMCs calcification by upregulating the expressions of TRPV1. Moreover, Cap reduced the expression of Wnt3a and β-catenin, whereas DKK1 antagonised the inhibitory effect of Cap on VSMC calcification. This study is the first to offer direct evidence that Cap inhibits the Wnt/β-catenin signaling pathway by upregulating the expression of the TRPV1 receptor, resulting in the decreased expression of Runx2 and BMP-2, thereby reducing VSMC calcification. Our study may provide novel strategies for preventing the progression of VC. This could serve as a theoretical basis for clinically treating VC with spicy foods.

Overexpression of miR-204-5p Alleviates Osteogenic Differentiation and Calcification of Human Aortic Vascular Smooth Muscle Cells by Targeting Calcium/Calmodulin-dependent Protein Kinase 1

ABSTRACT

Vascular calcification (VC), a major complication in chronic kidney disease (CKD), is predominantly driven by osteoblastic differentiation. Recent studies have highlighted the crucial role of microRNAs in CKD's pathogenesis. Here, our research focused on the effects of miR-204-5p and its molecular mechanisms within VC. We initially found a notable decrease in miR-204-5p levels in human aortic vascular smooth muscle cells stimulated with inorganic phosphate, using this as a VC model in vitro. Following the overexpression of miR-204-5p, a decrease in VC was observed, as indicated by alizarin red S staining and measurements of calcium content. This decrease was accompanied by lower levels of the osteogenic marker, runt-related transcription factor 2, and higher levels of α-smooth muscle actin, a marker of contractility. Further investigation showed that calcium/calmodulin-dependent protein kinase 1 (CAMK1), which is a predicted target of miR-204-5p, promotes VC. Conversely, overexpressing miR-204-5p reduced VC by suppressing CAMK1 activity. Overexpressing miR-204-5p also effectively mitigated aortic calcification in an in vivo rat model. In summary, our research indicated that targeting the miR-204-5p/CAMK1 pathway could be a viable strategy for mitigating VC in CKD patients.

Food to Prevent Vascular Calcification in Chronic Kidney Disease

Vascular calcification (VC) is a consequence of chronic kidney disease (CKD) which is of paramount importance regarding the survival of CKD patients. VC is far from being controlled with actual medication; as a result, in recent years, diet modulation has become more compelling. The concept of medical nutritional therapy points out the idea that food may prevent or treat diseases. The aim of this review was to evaluate the influence of food habits and nutritional intervention in the occurrence and progression of VC in CKD. Evidence reports the harmfulness of ultra-processed food, food additives, and animal-based proteins due to the increased intake of high absorbable phosphorus, the scarcity of fibers, and the increased production of uremic toxins. Available data are more supportive of a plant-dominant diet, especially for the impact on gut microbiota composition, which varies significantly depending on VC presence. Magnesium has been shown to prevent VC but only in experimental and small clinical studies. Vitamin K has drawn considerable attention due to its activation of VC inhibitors. There are positive studies; unfortunately, recent trials failed to prove its efficacy in preventing VC. Future research is needed and should aim to transform food into a medical intervention to eliminate VC danger in CKD.

Prevotella copri promotes vascular calcification via lipopolysaccharide through activation of NF-κB signaling pathway

Emerging evidence indicates that alteration of gut microbiota plays an important role in chronic kidney disease (CKD)-related vascular calcification (VC). We aimed to investigate the specific gut microbiota and the underlying mechanism involved in CKD-VC. We identified an increased abundance of Prevotella copri (P. copri) in the feces of CKD rats (induced by using 5/6 nephrectomy followed by a high calcium and phosphate diet) with aortic calcification via amplicon sequencing of 16S rRNA genes. In patients with CKD, we further confirmed a positive correlation between abundance of P. copri and aortic calcification scores. Moreover, oral administration of live P. copri aggravated CKD-related VC and osteogenic differentiation of vascular smooth muscle cells in vivo, accompanied by intestinal destruction, enhanced expression of Toll-like receptor-4 (TLR4), and elevated lipopolysaccharide (LPS) levels. In vitro and ex vivo experiments consistently demonstrated that P. copri-derived LPS (Pc-LPS) accelerated high phosphate-induced VC and VSMC osteogenic differentiation. Mechanistically, Pc-LPS bound to TLR4, then activated the nuclear factor κB (NF-κB) and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome signals during VC. Inhibition of NF-κB reduced NLRP3 inflammasome and attenuated Pc-LPS-induced VSMC calcification. Our study clarifies a novel role of P. copri in CKD-related VC, by the mechanisms involving increased inflammation-regulating metabolites including Pc-LPS, and activation of the NF-κB/NLRP3 signaling pathway. These findings highlight P. copri and its-derived LPS as potential therapeutic targets for VC in CKD.

[Ketone Body Metabolism and Renal Diseases]

A ketogenic diet limits energy supply from glucose and stimulates lipolysis, lipid oxidation, and ketogenesis, resulting in elevated levels of ketone bodies in the bloodstream. Ketone bodies are synthesized in the mitochondrial matrix of liver cells and β-hydroxybutyric acid (BHB) is the most abundant type of ketone body. Herein, we reviewed published findings on the metabolism of ketone bodies and the role of BHB in renal diseases. Through blood circulation, ketone bodies reach metabolically active tissues and provides an alternative source of energy. BHB, being a signaling molecule, mediates various types of cellular signal transduction and participates in the development and progression of many diseases. BHB also has protective and therapeutic effects on a variety of renal diseases. BHB improves the prognosis of renal diseases, such as diabetic kidney disease, chronic kidney disease, acute kidney injury, and polycystic kidney disease, through its antioxidant, anti-inflammatory, and stress response mechanisms. Previous studies have focused on the role of ketone bodies in regulating inflammation and oxidative stress in immune cells. Investigations into the effect of elevated levels of ketone bodies on the metabolism of renal podocytes and tubular cells remain inconclusive. Further research is needed to investigate the effect of BHB on podocyte damage and podocyte senescence in renal diseases.

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.

Inflammation and gut dysbiosis as drivers of CKD-MBD

Two decades ago, Kidney Disease: Improving Global Outcomes coined the term chronic kidney disease-mineral and bone disorder (CKD-MBD) to describe the syndrome of biochemical, bone and extra-skeletal calcification abnormalities that occur in patients with CKD. CKD-MBD is a prevalent complication and contributes to the excessively high burden of fractures and cardiovascular disease, loss of quality of life and premature mortality in patients with CKD. Thus far, therapy has focused primarily on phosphate retention, abnormal vitamin D metabolism and parathyroid hormone disturbances, but these strategies have largely proved unsuccessful, thus calling for paradigm-shifting concepts and innovative therapeutic approaches. Interorgan crosstalk is increasingly acknowledged to have an important role in health and disease. Accordingly, mounting evidence suggests a role for both the immune system and the gut microbiome in bone and vascular biology. Gut dysbiosis, compromised gut epithelial barrier and immune cell dysfunction are prominent features of the uraemic milieu. These alterations might contribute to the inflammatory state observed in CKD and could have a central role in the pathogenesis of CKD-MBD. The emerging fields of osteoimmunology and osteomicrobiology add another level of complexity to the pathogenesis of CKD-MBD, but also create novel therapeutic opportunities.

Cold exposure protects against medial arterial calcification development via autophagy

Medial arterial calcification (MAC), a systemic vascular disease different from atherosclerosis, is associated with an increased incidence of cardiovascular events. Several studies have demonstrated that ambient temperature is one of the most important factors affecting cardiovascular events. However, there has been limited research on the effect of different ambient temperatures on MAC. In the present study, we showed that cold temperature exposure (CT) in mice slowed down the formation of vitamin D (VD)-induced vascular calcification compared with room temperature exposure (RT). To investigate the mechanism involved, we isolated plasma-derived exosomes from mice subjected to CT or RT for 30 days (CT-Exo or RT-Exo, respectively). Compared with RT-Exo, CT-Exo remarkably alleviated the calcification/senescence formation of vascular smooth muscle cells (VSMCs) and promoted autophagy by activating the phosphorylation of AMP-activated protein kinase (p-AMPK) and inhibiting phosphorylation of mammalian target of rapamycin (p-mTOR). At the same time, CT-Exo promoted autophagy in β-glycerophosphate (β-GP)-induced VSMCs. The number of autophagosomes and the expression of autophagy-related proteins ATG5 and LC3B increased, while the expression of p62 decreased. Based on a microRNA chip microarray assay and real-time polymerase chain reaction, miR-320a-3p was highly enriched in CT-Exo as well as thoracic aortic vessels in CT mice. miR-320a-3p downregulation in CT-Exo using AntagomiR-320a-3p inhibited autophagy and blunted its anti-calcification protective effect on VSMCs. Moreover, we identified that programmed cell death 4 (PDCD4) is a target of miR-320a-3p, and silencing PDCD4 increased autophagy and decreased calcification in VSMCs. Treatment with CT-Exo alleviated the formation of MAC in VD-treated mice, while these effects were partially reversed by GW4869. Furthermore, the anti-arterial calcification protective effects of CT-Exo were largely abolished by AntagomiR-320a-3p in VD-induced mice. In summary, we have highlighted that prolonged cold may be a good way to reduce the incidence of MAC. Specifically, miR-320a-3p from CT-Exo could protect against the initiation and progression of MAC via the AMPK/mTOR autophagy pathway.

D-beta-hydroxybutyrate reduced the enhanced cardiac microvascular endothelial FoxO1 to play protective roles in diabetic rats and high glucose-stimulated human cardiac microvascular endothelial cells

The O subfamily of forkhead (FoxO) 1 may participate in the pathogenesis of diabetic microvascular endothelial injury. However, it is unknown whether D-beta-hydroxybutyrate (BHB) regulates cardiac microvascular endothelial FoxO1 to play protective roles in diabetes. In the study, limb microvascular morphological changes, endothelial distribution of the tight junction protein Claudin-5 and FoxO1, and FoxO1 content in limb tissue from clinical patients were evaluated. Then the effects of BHB on cardiac microvascular morphological changes, cardiac FoxO1 generation and its microvascular distribution in diabetic rats were measured. And the effects of BHB on FoxO1 generation in high glucose (HG)-stimulated human cardiac microvascular endothelial cells (HCMECs) were further analyzed. The results firstly confirmed the enhanced limb microvascular FoxO1 distribution, with reduced Claudin-5 and endothelial injury in clinical patients. Then the elevated FoxO1 generation and its enhanced cardiac microvascular distribution were verified in diabetic rats and HG-stimulated HCMECs. However, BHB inhibited the enhanced cardiac FoxO1 generation and its microvascular distribution with attenuation of endothelial injury in diabetic rats. Furthermore, BHB reduced the HG-stimulated mRNA expression and protein content of FoxO1 in HCMECs. In conclusion, BHB reduced the enhanced cardiac microvascular endothelial FoxO1 to play protective roles in diabetic rats and HG-stimulated HCMECs.

Ketone Bodies and Cardiovascular Disease: An Alternate Fuel Source to the Rescue

The increased metabolic activity of the heart as a pump involves a high demand of mitochondrial adenosine triphosphate (ATP) production for its mechanical and electrical activities accomplished mainly via oxidative phosphorylation, supplying up to 95% of the necessary ATP production, with the rest attained by substrate-level phosphorylation in glycolysis. In the normal human heart, fatty acids provide the principal fuel (40-70%) for ATP generation, followed mainly by glucose (20-30%), and to a lesser degree (<5%) by other substrates (lactate, ketones, pyruvate and amino acids). Although ketones contribute 4-15% under normal situations, the rate of glucose use is drastically diminished in the hypertrophied and failing heart which switches to ketone bodies as an alternate fuel which are oxidized in lieu of glucose, and if adequately abundant, they reduce myocardial fat delivery and usage. Increasing cardiac ketone body oxidation appears beneficial in the context of heart failure (HF) and other pathological cardiovascular (CV) conditions. Also, an enhanced expression of genes crucial for ketone break down facilitates fat or ketone usage which averts or slows down HF, potentially by avoiding the use of glucose-derived carbon needed for anabolic processes. These issues of ketone body utilization in HF and other CV diseases are herein reviewed and pictorially illustrated.

Deletion of SIRT6 in vascular smooth muscle cells facilitates vascular calcification via suppression of DNA damage repair

Vascular calcification is an important risk factor for cardiovascular events, accompanied by DNA damage during the process. The sirtuin 6 (SIRT6) has been reported to alleviate atherosclerosis, which is related to the reduction of DNA damage. However, whether smooth muscle cell SIRT6 mediates vascular calcification involving DNA damage remains unclear. Western blot and immunofluorescence revealed that SIRT6 expression was decreased in human vascular smooth muscle cells (HVSMCs), human and mouse arteries during vascular calcification. Alizarin red staining and calcium content assay showed that knockdown or deletion of SIRT6 significantly promoted HVSMC calcification induced by high phosphorus and calcium, accompanied by upregulation of osteogenic differentiation markers including Runx2 and BMP2. By contrast, adenovirus-mediated SIRT6 overexpression attenuated osteogenic differentiation and calcification of HVSMCs. Moreover, ex vivo study revealed that SIRT6 overexpression inhibited calcification of mouse and human arterial rings. Of note, smooth muscle cell-specific knockout of SIRT6 markedly aggravated Vitamin D₃-induced aortic calcification in mice. Mechanistically, overexpression of SIRT6 reduced DNA damage and upregulated p-ATM during HVSMCs calcification, whereas knockdown of SIRT6 showed the opposite effects. Knockdown of ATM in HVSMCs abrogated the inhibitory effect of SIRT6 overexpression on calcification and DNA damage. This study for the first time demonstrates that vascular smooth muscle cell-specific deletion of SIRT6 facilitates vascular calcification via suppression of DNA damage repair. Therefore, modulation of SIRT6 and DNA damage repair may represent a therapeutic strategy for vascular calcification.