Orphan Nuclear Receptor NR4A3 Promotes Vascular Calcification via Histone Lactylation.

BACKGROUND: Medial arterial calcification is a chronic systemic vascular disorder distinct from atherosclerosis and is commonly observed in patients with chronic kidney disease, diabetes, and aging individuals. We previously showed that NR4A3 (nuclear receptor subfamily 4 group A member 3), an orphan nuclear receptor, is a key regulator in apo (apolipoprotein) A-IV-induced atherosclerosis progression; however, its role in vascular calcification is poorly understood. METHODS: We generated NR4A3-/- mice and 2 different types of medial arterial calcification models to investigate the biological roles of NR4A3 in vascular calcification. RNA-seq was performed to determine the transcriptional profile of NR4A3-/- vascular smooth muscle cells under ß-glycerophosphate treatment. We integrated Cleavage Under Targets and Tagmentation analysis and RNA-seq data to further investigate the gene regulatory mechanisms of NR4A3 in arterial calcification and target genes regulated by histone lactylation. RESULTS: NR4A3 expression was upregulated in calcified aortic tissues from chronic kidney disease mice, 1,25(OH)2VitD3 overload-induced mice, and human calcified aorta. NR4A3 deficiency preserved the vascular smooth muscle cell contractile phenotype, inhibited osteoblast differentiation-related gene expression, and reduced calcium deposition in the vasculature. Further, NR4A3 deficiency lowered the glycolytic rate and lactate production during the calcification process and decreased histone lactylation. Mechanistic studies further showed that NR4A3 enhanced glycolysis activity by directly binding to the promoter regions of the 2 glycolysis genes ALDOA and PFKL and driving their transcriptional initiation. Furthermore, histone lactylation promoted medial calcification both in vivo and in vitro. NR4A3 deficiency inhibited the transcription activation and expression of Phospho1 (phosphatase orphan 1). Consistently, pharmacological inhibition of Phospho1 attenuated calcium deposition in NR4A3-overexpressed vascular smooth muscle cells, whereas overexpression of Phospho1 reversed the anticalcific effect of NR4A3 deficiency in vascular smooth muscle cells. CONCLUSIONS: Taken together, our findings reveal that NR4A3-mediated histone lactylation is a novel metabolome-epigenome signaling cascade mechanism that participates in the pathogenesis of medial arterial calcification.

Small particles with large impact: Insights into the unresolved roles of innate immunity in extracellular vesicle-mediated cardiovascular calcification.

Extracellular vesicles (EVs) are critical in the initiation and progression of cardiovascular calcification, and immune cell infiltration and inflammation have a central role in this process. EVs egress from various cardiovascular cell types, which when acquiring specific properties, become calcifying. These calcifying EVs form nidi for microcalcification, which can progress to the macrocalcification lesions that are visualized clinically. We make the distinction between inflammatory-driven and mineral dysregulation-driven calcification, which both share EVs as a central initiator. In inflammation-mediated calcification, inflammation precedes microcalcification and results from EV release from macrophages. Local cellular crosstalk mediated by EVs as well as circulating EVs and other inflammatory nanoparticles, such as calciprotein particles and lipoproteins, are also critical in the progression of cardiovascular calcification. It is imperative that future work links the already established and to be discovered roles of inflammation and innate immunity in cardiovascular calcification to these key signaling and functional roles of these nanoparticles. It remains an understudied area with high potential to unravel mechanistic roles and has important implications in drug target research.

Major Facilitator Superfamily Domain Containing 5 Inhibition Reduces Lipoprotein(a) Uptake and Calcification in Valvular Heart Disease.

BACKGROUND: High circulating levels of Lp(a) (lipoprotein[a]) increase the risk of atherosclerosis and calcific aortic valve disease, affecting millions of patients worldwide. Although atherosclerosis is commonly treated with low-density lipoprotein-targeting therapies, these do not reduce Lp(a) or risk of calcific aortic valve disease, which has no available drug therapies. Targeting Lp(a) production and catabolism may provide therapeutic benefit, but little is known about Lp(a) cellular uptake. METHODS: Here, unbiased ligand-receptor capture mass spectrometry was used to identify MFSD5 (major facilitator superfamily domain containing 5) as a novel receptor/cofactor involved in Lp(a) uptake. RESULTS: Reducing MFSD5 expression by a computationally identified small molecule or small interfering RNA suppressed Lp(a) uptake and calcification in primary human valvular endothelial and interstitial cells. MFSD5 variants were associated with aortic stenosis (P=0.027 after multiple hypothesis testing) with evidence suggestive of an interaction with plasma Lp(a) levels. CONCLUSIONS: MFSD5 knockdown suppressing human valvular cell Lp(a) uptake and calcification, along with meta-analysis of MFSD5 variants associating with aortic stenosis, supports further preclinical assessment of MFSD5 in cardiovascular diseases, the leading cause of death worldwide.

Carbonylation of Runx2 at K176 by 4-Hydroxynonenal Accelerates Vascular Calcification.

BACKGROUND: Vascular calcification, which is characterized by calcium deposition in arterial walls and the osteochondrogenic differentiation of vascular smooth muscle cells, is an actively regulated process that involves complex mechanisms. Vascular calcification is associated with increased cardiovascular adverse events. The role of 4-hydroxynonenal (4-HNE), which is the most abundant stable product of lipid peroxidation, in vascular calcification has been poorly investigated. METHODS: Serum was collected from patients with chronic kidney disease and controls, and the levels of 4-HNE and 8-iso-prostaglandin F2α were measured. Sections of coronary atherosclerotic plaques from donors were immunostained to analyze calcium deposition and 4-HNE. A total of 658 patients with coronary artery disease who received coronary computed tomography angiography were recruited to analyze the relationship between coronary calcification and the rs671 mutation in aldehyde dehydrogenase 2 (ALDH2). ALDH2 knockout (ALDH2-/-) mice, smooth muscle cell-specific ALDH2 knockout mice, ALDH2 transgenic mice, and their controls were used to establish vascular calcification models. Primary mouse aortic smooth muscle cells and human aortic smooth muscle cells were exposed to medium containing ß-glycerophosphate and CaCl2 to investigate cell calcification and the underlying molecular mechanisms. RESULTS: Elevated 4-HNE levels were observed in the serum of patients with chronic kidney disease and model mice and were detected in calcified artery sections by immunostaining. ALDH2 knockout or smooth muscle cell-specific ALDH2 knockout accelerated the development of vascular calcification in model mice, whereas overexpression or activation prevented mouse vascular calcification and the osteochondrogenic differentiation of vascular smooth muscle cells. In patients with coronary artery disease, patients with ALDH2 rs671 gene mutation developed more severe coronary calcification. 4-HNE promoted calcification of both mouse aortic smooth muscle cells and human aortic smooth muscle cells and their osteochondrogenic differentiation in vitro. 4-HNE increased the level of Runx2 (runt-related transcription factor-2), and the effect of 4-HNE on promoting vascular smooth muscle cell calcification was ablated when Runx2 was knocked down. Mutation of Runx2 at lysine 176 reduced its carbonylation and eliminated the 4-HNE-induced upregulation of Runx2. CONCLUSIONS: Our results suggest that 4-HNE increases Runx2 stabilization by directly carbonylating its K176 site and promotes vascular calcification. ALDH2 might be a potential target for the treatment of vascular calcification.

Coronary Artery Calcification: Current Concepts and Clinical Implications.

Coronary artery calcification (CAC) accompanies the development of advanced atherosclerosis. Its role in atherosclerosis holds great interest because the presence and burden of coronary calcification provide direct evidence of the presence and extent of coronary artery disease; furthermore, CAC predicts future events independently of concomitant conventional cardiovascular risk factors and to a greater extent than any other noninvasive biomarker of this disease. Nevertheless, the relationship between CAC and the susceptibility of a plaque to provoke a thrombotic event remains incompletely understood. This review summarizes the current understanding and literature on CAC. It outlines the pathophysiology of CAC and reviews laboratory, histopathological, and genetic studies, as well as imaging findings, to characterize different types of calcification and to elucidate their implications. Some patterns of calcification such as microcalcification portend increased risk of rupture and cardiovascular events and may improve prognosis assessment noninvasively. However, contemporary computed tomography cannot assess early microcalcification. Limited spatial resolution and blooming artifacts may hinder estimation of degree of coronary artery stenosis. Technical advances such as photon counting detectors and combination with nuclear approaches (eg, NaF imaging) promise to improve the performance of cardiac computed tomography. These innovations may speed achieving the ultimate goal of providing noninvasively specific and clinically actionable information.

HDAC2 counteracts vascular calcification by activating autophagy in chronic kidney disease.

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

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.

Cardiovascular Calcification Heterogeneity in Chronic Kidney Disease.

Patients with chronic kidney disease (CKD) exhibit tremendously elevated risk for cardiovascular disease, particularly ischemic heart disease, due to premature vascular and cardiac aging and accelerated ectopic calcification. The presence of cardiovascular calcification associates with increased risk in patients with CKD. Disturbed mineral homeostasis and diverse comorbidities in these patients drive increased systemic cardiovascular calcification in different manifestations with diverse clinical consequences, like plaque instability, vessel stiffening, and aortic stenosis. This review outlines the heterogeneity in calcification patterning, including mineral type and location and potential implications on clinical outcomes. The advent of therapeutics currently in clinical trials may reduce CKD-associated morbidity. Development of therapeutics for cardiovascular calcification begins with the premise that less mineral is better. While restoring diseased tissues to a noncalcified homeostasis remains the ultimate goal, in some cases, calcific mineral may play a protective role, such as in atherosclerotic plaques. Therefore, developing treatments for ectopic calcification may require a nuanced approach that considers individual patient risk factors. Here, we discuss the most common cardiac and vascular calcification pathologies observed in CKD, how mineral in these tissues affects function, and the potential outcomes and considerations for therapeutic strategies that seek to disrupt the nucleation and growth of mineral. Finally, we discuss future patient-specific considerations for treating cardiac and vascular calcification in patients with CKD-a population in need of anticalcification therapies.

FHL5 Controls Vascular Disease-Associated Gene Programs in Smooth Muscle Cells.

BACKGROUND: Genome-wide association studies have identified hundreds of loci associated with common vascular diseases, such as coronary artery disease, myocardial infarction, and hypertension. However, the lack of mechanistic insights for many GWAS loci limits their translation into the clinic. Among these loci with unknown functions is UFL1-four-and-a-half LIM (LIN-11, Isl-1, MEC-3) domain 5 (FHL5; chr6q16.1), which reached genome-wide significance in a recent coronary artery disease/ myocardial infarction GWAS meta-analysis. UFL1-FHL5 is also associated with several vascular diseases, consistent with the widespread pleiotropy observed for GWAS loci. METHODS: We apply a multimodal approach leveraging statistical fine-mapping, epigenomic profiling, and ex vivo analysis of human coronary artery tissues to implicate FHL5 as the top candidate causal gene. We unravel the molecular mechanisms of the cross-phenotype genetic associations through in vitro functional analyses and epigenomic profiling experiments in coronary artery smooth muscle cells. RESULTS: We prioritized FHL5 as the top candidate causal gene at the UFL1-FHL5 locus through expression quantitative trait locus colocalization methods. FHL5 gene expression was enriched in the smooth muscle cells and pericyte population in human artery tissues with coexpression network analyses supporting a functional role in regulating smooth muscle cell contraction. Unexpectedly, under procalcifying conditions, FHL5 overexpression promoted vascular calcification and dysregulated processes related to extracellular matrix organization and calcium handling. Lastly, by mapping FHL5 binding sites and inferring FHL5 target gene function using artery tissue gene regulatory network analyses, we highlight regulatory interactions between FHL5 and downstream coronary artery disease/myocardial infarction loci, such as FOXL1 and FN1 that have roles in vascular remodeling. CONCLUSIONS: Taken together, these studies provide mechanistic insights into the pleiotropic genetic associations of UFL1-FHL5. We show that FHL5 mediates vascular disease risk through transcriptional regulation of downstream vascular remodeling gene programs. These transacting mechanisms may explain a portion of the heritable risk for complex vascular diseases.

Extent of Abdominal Aortic Calcification Is Associated With Incident Rapid Weight Loss Over 5 Years: The Perth Longitudinal Study of Ageing Women.

BACKGROUND: Abdominal aortic calcification (AAC), a marker of vascular disease, is associated with disease in other vascular beds including gastrointestinal arteries. We investigated whether AAC is related to rapid weight loss over 5 years and whether rapid weight loss is associated with 9.5-year all-cause mortality in community-dwelling older women. METHODS: Lateral spine images from dual-energy x-ray absorptiometry (1998/1999) were used to assess AAC (24-point AAC scoring method) in 929 older women. Over 5 years, body weight was assessed at 12-month intervals. Rapid weight loss was defined as >5% decrease in body weight within any 12-month interval. Multivariable-adjusted logistic regression was used to assess AAC and rapid weight loss and Cox regression to assess the relationship between rapid weight loss and 9.5-year all-cause mortality. RESULTS: Mean±SD age of women was 75.0±2.6 years. During the initial 5 years, 366 (39%) women presented with rapid weight loss. Compared with women with low AAC (24-point AAC score 0-1), those with moderate (24-point AAC score 2-5: odds ratio, 1.36 [95% CI, 1.00-1.85]) and extensive (24-point AAC score 6+: odds ratio, 1.59 [95% CI, 1.10-2.31]) AAC had higher odds for presenting with rapid weight loss. Results remained similar after further adjustment for dietary factors (alcohol, protein, fat, and carbohydrates), diet quality, blood pressure, and cholesterol measures. The estimates were similar in subgroups of women who met protein intake (n=599) and physical activity (n=735) recommendations (extensive AAC: odds ratios, 1.81 [95% CI, 1.12-2.92] and 1.58 [95% CI, 1.02-2.44], respectively). Rapid weight loss was associated with all-cause mortality over the next 9.5 years (hazard ratio, 1.49 [95% CI, 1.17-1.89]; P=0.001). CONCLUSIONS: AAC extent was associated with greater risk for rapid weight loss over 5 years in older women, a risk for all-cause mortality. Since the association was unchanged after taking nutritional intakes into account, these data support the possibility that vascular disease may play a role in the maintenance of body weight.

Spatial Atlas for Mapping Vascular Microcalcification Using 18F-NaF PET/CT: Application in Hyperphosphatemic Familial Tumoral Calcinosis.

BACKGROUND: Vascular calcification causes significant morbidity and occurs frequently in diseases of calcium/phosphate imbalance. Radiolabeled sodium fluoride positron emission tomography/computed tomography has emerged as a sensitive and specific method for detecting and quantifying active microcalcifications. We developed a novel technique to quantify and map total vasculature microcalcification to a common space, allowing simultaneous assessment of global disease burden and precise tracking of site-specific microcalcifications across time and individuals. METHODS: To develop this technique, 4 patients with hyperphosphatemic familial tumoral calcinosis, a monogenic disorder of FGF23 (fibroblast growth factor-23) deficiency with a high prevalence of vascular calcification, underwent radiolabeled sodium fluoride positron emission tomography/computed tomography imaging. One patient received serial imaging 1 year after treatment with an IL-1 (interleukin-1) antagonist. A radiolabeled sodium fluoride-based microcalcification score, as well as calcification volume, was computed at all perpendicular slices, which were then mapped onto a standardized vascular atlas. Segment-wise mCSmean and mCSmax were computed to compare microcalcification score levels at predefined vascular segments within subjects. RESULTS: Patients with hyperphosphatemic familial tumoral calcinosis had notable peaks in microcalcification score near the aortic bifurcation and distal femoral arteries, compared with a control subject who had uniform distribution of vascular radiolabeled sodium fluoride uptake. This technique also identified microcalcification in a 17-year-old patient, who had no computed tomography-defined calcification. This technique could not only detect a decrease in microcalcification score throughout the patient treated with an IL-1 antagonist but it also identified anatomic areas that had increased responsiveness while there was no change in computed tomography-defined macrocalcification after treatment. CONCLUSIONS: This technique affords the ability to visualize spatial patterns of the active microcalcification process in the peripheral vasculature. Further, this technique affords the ability to track microcalcifications at precise locations not only across time but also across subjects. This technique is readily adaptable to other diseases of vascular calcification and may represent a significant advance in the field of vascular biology.

Vascular Calcification Is Accelerated by Hyponatremia and Low Osmolality.

BACKGROUND: Hyponatremia, frequently observed in patients with chronic kidney disease, is associated with increased cardiovascular morbidity and mortality. Hyponatremia or low osmolality induces oxidative stress and cell death, both of which accelerate vascular calcification (VC), a critical phenotype in patients with chronic kidney disease. Whether hyponatremia or low osmolality plays a role in the pathogenesis of VC is unknown. METHODS: Human vascular smooth muscle cells (VSMCs) and mouse aortic rings were cultured in various osmotic conditions and calcifying medium supplemented with high calcium and phosphate. The effects of low osmolality on phenotypic change and oxidative stress in the cultured VSMCs were examined. Microarray analysis was conducted to determine the main signaling pathway of osmolality-related VC. The transcellular sodium and calcium ions flux across the VSMCs were visualized by live imaging. Furthermore, the effect of osmolality on calciprotein particles (CPPs) was investigated. Associations between arterial intimal calcification and hyponatremia or low osmolality were examined by a cross-sectional study using human autopsy specimens obtained in the Hisayama Study. RESULTS: Low osmolality exacerbated calcification of the ECM (extracellular matrix) of cultured VSMCs and mouse aortic rings. Oxidative stress and osteogenic differentiation of VSMCs were identified as the underlying mechanisms responsible for low osmolality-induced VC. Microarray analysis showed that low osmolality activated the Rac1 (Ras-related C3 botulinum toxin substrate 1)-Akt (protein kinase B) pathway and reduced NCX1 (Na-Ca exchanger 1) expression. Live imaging showed synchronic calcium ion efflux and sodium ion influx via NCX1 when extracellular sodium ion concentrations were increased. An NCX1 inhibitor promoted calcifying media-induced VC by reducing calcium ion efflux. Furthermore, low osmolality accelerated the generation and maturation steps of CPPs. The cross-sectional study of human autopsy specimens showed that hyponatremia and low osmolality were associated with a greater area of arterial intimal calcification. CONCLUSIONS: Hyponatremia and low osmolality promote VC through multiple cellular processes, including the Rac1-Akt pathway activation.

Aortic Uptake of 18F-NaF and 18F-FDG and Calcification Predict the Development of Abdominal Aortic Aneurysms and Is Attenuated by Drug Therapy.

BACKGROUND: Abdominal aortic aneurysms expand over time and increase the risk of fatal ruptures. To predict expansion, the isolated assessment of 18F-fluorodeoxyglucose (FDG) and sodium fluoride (NaF) uptake or calcification volume in aneurysms has been investigated with variability in results. We systematically evaluated whether 18F-FDG and 18F-NaF uptake was predictive of abdominal aortic aneurysm expansion. METHODS: Seventy-four male Sprague-Dawley rat abdominal aortic aneurysm models were imaged using positron emission tomography-computed tomography with 18F-FDG and 18F-NaF at 1, 2, 4, 6, and 8 weeks after CaCl2 or saline stimulation. In the 1-week cohort (n=25), the correlation between 18F-FDG or 18F-NaF uptake and pathological markers was investigated. In the time course cohort (n=49), animals received either atorvastatin, losartan, aldactone, or risedronate to assess the effect of these drugs, and the relationship between aortic size and sequential 18F-FDG and 18F-NaF uptake or calcification volume was examined. RESULTS: In the 1-week cohort, the maximum standard unit value of 18F-FDG and 18F-NaF uptake correlated with CD68- (r=0.82; P=0.001) and von Kossa staining-positive areas (r=0.89; P<0.001), respectively. In the time course cohort, 18F-FDG and 18F-NaF uptake changed in a time-dependent manner and drugs attenuated this uptake. Specifically, 18F-FDG showed high uptake at weeks 1 and 2, whereas a high 18F-NaF uptake was noted throughout the study period. Atorvastatin and risedronate showed a decreased and increased aortic size, respectively. The final aortic area correlated well with 18F-FDG and 18F-NaF uptake and calcification volume, especially at 1 and 2 weeks (18F-NaF [1 week]: r=0.61, 18F-FDG [2 weeks]: r=0.51, calcification volume [1 week]: r=0.59; P<0.001). Multiple linear regression analysis showed that the combination of these factors predicted the final aortic size, with 18F-NaF uptake at 1 week being the strongest predictor. CONCLUSIONS: The uptake of 18F-NaF and 18F-FDG and the calcification volume at appropriate times correlated with the development of abdominal aortic aneurysms, with 18F-NaF uptake being the strongest predictor.

Phosphate in Cardiovascular Disease: From New Insights Into Molecular Mechanisms to Clinical Implications.

Hyperphosphatemia is a common feature in patients with impaired kidney function and is associated with increased risk of cardiovascular disease. This phenomenon extends to the general population, whereby elevations of serum phosphate within the normal range increase risk; however, the mechanism by which this occurs is multifaceted, and many aspects are poorly understood. Less than 1% of total body phosphate is found in the circulation and extracellular space, and its regulation involves multiple organ cross talk and hormones to coordinate absorption from the small intestine and excretion by the kidneys. For phosphate to be regulated, it must be sensed. While mostly enigmatic, various phosphate sensors have been elucidated in recent years. Phosphate in the circulation can be buffered, either through regulated exchange between extracellular and cellular spaces or through chelation by circulating proteins (ie, fetuin-A) to form calciprotein particles, which in themselves serve a function for bulk mineral transport and signaling. Either through direct signaling or through mediators like hormones, calciprotein particles, or calcifying extracellular vesicles, phosphate can induce various cardiovascular disease pathologies: most notably, ectopic cardiovascular calcification but also left ventricular hypertrophy, as well as bone and kidney diseases, which then propagate phosphate dysregulation further. Therapies targeting phosphate have mostly focused on intestinal binding, of which appreciation and understanding of paracellular transport has greatly advanced the field. However, pharmacotherapies that target cardiovascular consequences of phosphate directly, such as vascular calcification, are still an area of great unmet medical need.

Serum Calcification Propensity Is Increased in Myocardial Infarction and Hints at a Pathophysiological Role Independent of Classical Cardiovascular Risk Factors.

BACKGROUND: Vascular calcification is associated with increased mortality in patients with cardiovascular disease. Secondary calciprotein particles are believed to play a causal role in the pathophysiology of vascular calcification. The maturation time (T50) of calciprotein particles provides a measure of serum calcification propensity. We compared T50 between patients with ST-segment-elevated myocardial infarction and control subjects and studied the association of T50 with cardiovascular risk factors and outcome. METHODS: T50 was measured by nephelometry in 347 patients from the GIPS-III trial (Metabolic Modulation With Metformin to Reduce Heart Failure After Acute Myocardial Infarction: Glycometabolic Intervention as Adjunct to Primary Coronary Intervention in ST Elevation Myocardial Infarction: a Randomized Controlled Trial) and in 254 matched general population controls from PREVEND (Prevention of Renal and Vascular End-Stage Disease). We also assessed the association between T50 and left ventricular ejection fraction, as well as infarct size, the incidence of ischemia-driven reintervention during 5 years of follow-up, and serum nitrite as a marker of endothelial dysfunction. RESULTS: Patients with ST-segment-elevated myocardial infarction had a significantly lower T50 (ie, higher serum calcification propensity) compared with controls (T50: 289±63 versus 338±56 minutes; P<0.001). In patients with ST-segment-elevated myocardial infarction, lower T50 was associated with female sex, lower systolic blood pressure, lower total cholesterol, lower LDL (low-density lipoprotein) cholesterol, lower triglycerides, and higher HDL (high-density lipoprotein) cholesterol but not with circulating nitrite or nitrate. Ischemia-driven reintervention was associated with higher LDL (P=0.03) and had a significant interaction term for T50 and sex (P=0.005), indicating a correlation between ischemia-driven reintervention and T50 above the median in men and below the median in women, between 150 days and 5 years of follow-up. CONCLUSIONS: Serum calcification propensity is increased in patients with ST-segment-elevated myocardial infarction compared with the general population, and its contribution is more pronounced in women than in men. Its lack of/inverse association with nitrite and blood pressure confirms T50 to be orthogonal to traditional cardiovascular disease risk factors. Lower T50 was associated with a more favorable serum lipid profile, suggesting the involvement of divergent pathways of calcification stress and lipid stress in the pathophysiology of myocardial infarction.

CircTOP1 targeted regulation of PTBP1 expression promotes the progression of coronary artery calcification.

Coronary artery calcification (CAC) is a hallmark event in the pathogenesis of cardiovascular disease, involving the phenotypic transformation of vascular smooth muscle cells (VSMC) towards an osteogenic state. Despite this understanding, the molecular mechanisms governing the VSMC osteogenic switch remain incompletely elucidated. Here, we sought to examine the potential role of circular RNA (circRNA) in the context of CAC. Through transcriptome analysis of circRNA-seq, we identified circTOP1 as a potential candidate circRNA in individuals with CAC. Furthermore, we observed that overexpression of circTOP1 exacerbated vascular calcification in a CAC model. Subsequent pull-down assays revealed an interaction between circTOP1 and PTBP1, a putative target gene of circTOP1 in the context of CAC. In both in vivo and in vitro experiments, we observed heightened expression of circTOP1 and PTBP1 in the CAC model, and noted that reducing circTOP1 expression effectively reduced calcium salt deposits and mineralized nodules in model mice. Additionally, in vitro experiments demonstrated that overexpression of PTBP1 reversed the weakening of signaling caused by silencing circTOP1, thereby exacerbating the osteogenic transition and calcification of VSMC. Collectively, our findings suggested that circTOP1 promotes CAC by modulating PTBP1 expression to mediate VSMC transdifferentiation.

12,13-diHOME attenuates high glucose-induced calcification of vascular smooth muscle cells through repressing CPT1A-mediated HMGB1 succinylation.

Diabetes is closely associated with vascular calcification (VC). Exorbitant glucose concentration activates pro-calcific effects in vascular smooth muscle cells (VSMCs). This study enrolled 159 elderly patients with type 2 diabetes and divided them into three groups, T1, T2 and T3, according to brachial-ankle pulse wave velocity(BaPWV). There were statistically significant differences in the waist circumference, waist hip ratio, systolic blood pressure, 12,13-diHOME (a lipokin) concentration among T1, T2 and T3. 12,13-diHOME levels were positively correlated to high density lipoprotein cholesterol and total cholesterol, but negatively correlated to with waist circumference, waist hip ratio, systolic blood pressure and baPWV. Studies in vitro showed that 12,13-diHOME effectively inhibits calcification in VSMCs under high glucose conditions. Notably, 12,13-diHOME suppressed the up-regulation of carnitine O-palmitoyltransferase 1 (CPT1A) and CPT1A-induced succinylation of HMGB1. The succinylation of HMGB1 at the K90 promoted the protein stability and induced the enrichment of HMGB1 in cytoplasm, which induced the calcification in VSMCs. Together, 12,13-diHOME attenuates high glucose-induced calcification in VSMCs through repressing CPT1A-mediated HMGB1 succinylation.

Causal effects of osteoporosis on structural changes in specific brain regions: a Mendelian randomization study.

Observational studies have reported that osteoporosis is associated with cortical changes in the brain. However, the inherent limitations of observational studies pose challenges in eliminating confounding factors and establishing causal relationships. And previous observational studies have not reported changes in specific brain regions. By employing Mendelian randomization, we have been able to infer a causal relationship between osteoporosis and a reduction in the surficial area (SA) of the brain cortical. This effect is partially mediated by vascular calcification. We found that osteoporosis significantly decreased the SA of global brain cortical (ß = -1587.62 mm2, 95%CI: -2645.94 mm2 to -529.32 mm2, P = 0.003) as well as the paracentral gyrus without global weighted (ß = - 19.42 mm2, 95%CI: -28.90 mm2 to -9.95 mm2, P = 5.85 × 10-5). Furthermore, we estimated that 42.25% and 47.21% of the aforementioned effects are mediated through vascular calcification, respectively. Osteoporosis leads to a reduction in the SA of the brain cortical, suggesting the presence of the bone-brain axis. Vascular calcification plays a role in mediating this process to a certain extent. These findings establish a theoretical foundation for further investigations into the intricate interplay between bone, blood vessels, and the brain.

PALMD haploinsufficiency aggravates extracellular matrix remodeling in vascular smooth muscle cells and promotes calcification.

Reduced PALMD expression is strongly associated with the development of calcified aortic valve stenosis; however, the role of PALMD in vascular calcification remains unknown. Calcified arteries were collected from mice to detect PALMD expression. Heterozygous Palmd knockout (Palmd+/-) mice were established to explore the role of PALMD in subtotal nephrectomy-induced vascular calcification. RNA sequencing was applied to detect molecular changes in aortas from Palmd+/- mice. Primary Palmd+/- vascular smooth muscle cells (VSMCs) or PALMD-silenced VSMCs by short interfering RNA were used to analyze PALMD function in phenotypic changes and calcification. PALMD haploinsufficiency aggravated subtotal nephrectomy-induced vascular calcification. RNA sequencing analysis showed that loss of PALMD disturbed the synthesis and degradation of the extracellular matrix (ECM) in aortas, including collagens and matrix metalloproteinases (Col6a6, Mmp2, Mmp9, etc.). In vitro experiments revealed that PALMD-deficient VSMCs were more susceptible to high phosphate-induced calcification. Downregulation of SMAD6 expression and increased levels of p-SMAD2 were detected in Palmd+/- VSMCs, suggesting that transforming growth factor-ß signaling may be involved in PALMD haploinsufficiency-induced vascular calcification. Our data revealed that PALMD haploinsufficiency causes ECM dysregulation in VSMCs and aggravates vascular calcification. Our findings suggest that reduced PALMD expression is also linked to vascular calcification, and PALMD may be a potential therapeutic target for this disease. NEW & NOTEWORTHY We found that PALMD haploinsufficiency causes extracellular matrix dysregulation, reduced PALMD expression links to vascular calcification, and PALMD mutations may lead to the risk of both calcific aortic valve stenosis and vascular calcification.

NEAT1 regulates VSMC differentiation and calcification in as long noncoding RNA NEAT1 enhances phenotypic and osteogenic switching of vascular smooth muscle cells in atherosclerosis via scaffolding EZH2.

Atherosclerosis (AS) is a significant contributor to cardio-cerebrovascular ischemia diseases, resulting in high mortality rates worldwide. During AS, vascular smooth muscle cells (VSMCs) play a crucial role in plaque formation by undergoing phenotypic and osteogenic switching. Long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) has previously been identified as a nuclear regulator that promotes tumorigenesis and metastasis, but its role in regulating VSMCs in AS remains unclear. Our study aimed to investigate the biological functions and specific mechanisms of NEAT1 in regulating VSMCs in AS. We found that NEAT1 was upregulated in the aortas of AS mouse models and dedifferentiated primary VSMCs. Silencing NEAT1 in vitro attenuated the proliferation, migration, and osteogenic differentiation of VSMCs, while NEAT1 overexpression had the opposite effect. Furthermore, NEAT1 promoted VSMC osteogenic differentiation and vascular calcification in both in vivo and in vitro vascular calcification models. We also discovered that NEAT1 directly activates enhancer of zeste homolog 2 (EZH2), an epigenetic enzyme that suppresses the expression of senescence- and antimigration-related genes, by translocating it into the nucleus. CUT&Tag assay revealed that NEAT1 guides EZH2 to the promoters of senescence-related genes (P16, P21, and TIMP3), methylating local histones to reduce their transcription. Our findings suggest that NEAT1 functions in AS by modulating the epigenetic function of EZH2, which enhances the proliferation, migration, and osteogenic differentiation of VSMCs. This study provides new insights into the molecular mechanisms underlying the pathogenesis of AS and highlights the potential of NEAT1 as a therapeutic target of AS.NEW & NOTEWORTHY Our study demonstrates that the upregulation of long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) promotes proliferation and migration during phenotypic switching of vascular smooth muscle cells in atherosclerosis. We also provide in vivo and in vitro evidence that NEAT1 accelerates vascular calcification. Our findings identified the direct interaction between enhancer of zeste homolog 2 (EZH2) and NEAT1 during atherosclerosis. NEAT1 is necessary for EZH2 to translocate from the cytoplasm to the nucleus, where EZH2 epigenetically inhibits the expression of genes related to senescence and antimigration.