Bone morphogenetic protein 6 and oxidized low-density lipoprotein synergistically recruit osteogenic differentiation in endothelial cells

Placental Tissue Calcification and Its Molecular Pathways in Female Patients with Late-Onset Preeclampsia

Preeclampsia (PE) is a complex multisystem disease characterized by hypertension of sudden onset (>20 weeks' gestation) coupled with the presence of at least one additional complication, such as proteinuria, maternal organ dysfunction, or uteroplacental dysfunction. Hypertensive states during pregnancy carry life-threatening risks for both mother and baby. The pathogenesis of PE develops due to a dysfunctional placenta with aberrant architecture that releases factors contributing to endothelial dysfunction, an antiangiogenic state, increased oxidative stress, and maternal inflammatory responses. Previous studies have shown a correlation between grade 3 placental calcifications and an elevated risk of developing PE at term. However, little is known about the molecular pathways leading to placental calcification. In this work, we studied the gene and protein expression of c-Jun N-terminal kinase (JNK), Runt-related transcription factor 2 (RUNX2), osteocalcin (OSC), osteopontin (OSP), pigment epithelium-derived factor (PEDF), MSX-2/HOX8, SOX-9, WNT-1, and β-catenin in placental tissue from women with late-onset PE (LO-PE). In addition, we employed von Kossa staining to detect mineral deposits in placental tissues. Our results show a significant increase of all these components in placentas from women with LO-PE. Therefore, our study suggests that LO-PE may be associated with the activation of molecular pathways of placental calcification. These results could be the starting point for future research to describe the molecular mechanisms that promote placental calcification in PE and the development of therapeutic strategies directed against it.

Key regulators of vascular calcification in chronic kidney disease: Hyperphosphatemia, BMP2, and RUNX2

Vascular calcification is quite common in patients with end-stage chronic kidney disease and is a major trigger for cardiovascular complications in these patients. These complications significantly impact the survival rate and long-term prognosis of individuals with chronic kidney disease. Numerous studies have demonstrated that the development of vascular calcification involves various pathophysiological mechanisms, with the osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) being of utmost importance. High phosphate levels, bone morphogenetic protein 2 (BMP2), and runt-related transcription factor 2 (RUNX2) play crucial roles in the osteogenic transdifferentiation process of VSMCs. This article primarily reviews the molecular mechanisms by which high phosphate, BMP2, and RUNX2 regulate vascular calcification secondary to chronic kidney disease, and discusses the complex interactions among these factors and their impact on the progression of vascular calcification. The insights provided here aim to offer new perspectives for future research on the phenotypic switching and osteogenic transdifferentiation of VSMCs, as well as to aid in optimizing clinical treatment strategies for this condition, bearing significant clinical and scientific implications.

Transcriptomic analysis reveals molecular characterization and immune landscape of PANoptosis-related genes in atherosclerosis

BACKGROUND

Atherosclerosis is a chronic inflammatory disease characterized by abnormal lipid deposition in the arteries. Programmed cell death is involved in the inflammatory response of atherosclerosis, but PANoptosis, as a new form of programmed cell death, is still unclear in atherosclerosis. This study explored the key PANoptosis-related genes involved in atherosclerosis and their potential mechanisms through bioinformatics analysis.

METHODS

We evaluated differentially expressed genes (DEGs) and immune infiltration landscape in atherosclerosis using microarray datasets and bioinformatics analysis. By intersecting PANoptosis-related genes from the GeneCards database with DEGs, we obtained a set of PANoptosis-related genes in atherosclerosis (PANoDEGs). Functional enrichment analysis of PANoDEGs was performed and protein-protein interaction (PPI) network of PANoDEGs was established. The machine learning algorithms were used to identify the key PANoDEGs closely linked to atherosclerosis. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic potency of key PANoDEGs. CIBERSORT was used to analyze the immune infiltration patterns in atherosclerosis, and the Spearman method was used to study the relationship between key PANoDEGs and immune infiltration abundance. The single gene enrichment analysis of key PANoDEGs was investigated by GSEA. The transcription factors and target miRNAs of key PANoDEGs were predicted by Cytoscape and online database, respectively. The expression of key PANoDEGs was validated through animal and cell experiments.

RESULTS

PANoDEGs in atherosclerosis were significantly enriched in apoptotic process, pyroptosis, necroptosis, cytosolic DNA-sensing pathway, NOD-like receptor signaling pathway, lipid and atherosclerosis. Four key PANoDEGs (ZBP1, SNHG6, DNM1L, and AIM2) were found to be closely related to atherosclerosis. The ROC curve analysis demonstrated that the key PANoDEGs had a strong diagnostic potential in distinguishing atherosclerotic samples from control samples. Immune cell infiltration analysis revealed that the proportion of initial B cells, plasma cells, CD4 memory resting T cells, and M1 macrophages was significantly higher in atherosclerotic tissues compared to normal tissues. Spearman analysis showed that key PANoDEGs showed strong correlations with immune cells such as T cells, macrophages, plasma cells, and mast cells. The regulatory networks of the four key PANoDEGs were established. The expression of key PANoDEGs was verified in further cell and animal experiments.

CONCLUSIONS

This study evaluated the expression changes of PANoptosis-related genes in atherosclerosis, providing a reference direction for the study of PANoptosis in atherosclerosis and offering potential new avenues for further understanding the pathogenesis and treatment strategies of atherosclerosis.

Elucidating the crosstalk between endothelial-to-mesenchymal transition (EndoMT) and endothelial autophagy in the pathogenesis of atherosclerosis

Atherosclerosis, a chronic systemic inflammatory condition, is implicated in most cardiovascular ischemic events. The pathophysiology of atherosclerosis involves various cell types and associated processes, including endothelial cell activation, monocyte recruitment, smooth muscle cell migration, involvement of macrophages and foam cells, and instability of the extracellular matrix. The process of endothelial-to-mesenchymal transition (EndoMT) has recently emerged as a pivotal process in mediating vascular inflammation associated with atherosclerosis. This transition occurs gradually, with a significant portion of endothelial cells adopting an intermediate state, characterized by a partial loss of endothelial-specific gene expression and the acquisition of "mesenchymal" traits. Consequently, this shift disrupts endothelial cell junctions, increases vascular permeability, and exacerbates inflammation, creating a self-perpetuating cycle that drives atherosclerotic progression. While endothelial cell dysfunction initiates the development of atherosclerosis, autophagy, a cellular catabolic process designed to safeguard cells by recycling intracellular molecules, is believed to exert a significant role in plaque development. Identifying the pathological mechanisms and molecular mediators of EndoMT underpinning endothelial autophagy, may be of clinical relevance. Here, we offer new insights into the underlying biology of atherosclerosis and present potential molecular mechanisms of atherosclerotic resistance and highlight potential therapeutic targets.

MicroRNAs regulate the vicious cycle of vascular calcification-osteoporosis in postmenopausal women

Menopause is a normal physiological process accompanied by changes in various physiological states. The incidence of vascular calcification (VC) increases each year after menopause and is closely related to osteoporosis (OP). Although many studies have investigated the links between VC and OP, the interaction mechanism of the two under conditions of estrogen loss remains unclear. MicroRNAs (miRNAs), which are involved in epigenetic modification, play a critical role in estrogen-mediated mineralization. In the past several decades, miRNAs have been identified as biomarkers or therapeutic targets in diseases. Thus, we hypothesize that these small molecules can provide new diagnostic and therapeutic approaches. In this review, we summarize the close interactions between VC and OP and the role of miRNAs in their interplay.

Strategies for arterial graft optimization at the single-cell level

Common arterial grafts used in coronary artery bypass grafting include internal thoracic artery (ITA), radial artery (RA) and right gastroepiploic artery (RGA) grafts; of these, the ITA has the best clinical outcome. Here, by analyzing the single-cell transcriptome of different arterial grafts, we suggest optimization strategies for the RA and RGA based on the ITA as a reference. Compared with the ITA, the RA had more lipid-handling-related CD36+ endothelial cells. Vascular smooth muscle cells from the RGA were more susceptible to spasm, followed by those from the RA; comparison with the ITA suggested that potassium channel openers may counteract vasospasm. Fibroblasts from the RA and RGA highly expressed GDF10 and CREB5, respectively; both GDF10 and CREB5 are associated with extracellular matrix deposition. Cell-cell communication analysis revealed high levels of macrophage migration inhibitory factor signaling in the RA. Administration of macrophage migration inhibitory factor inhibitor to mice with partial carotid artery ligation blocked neointimal hyperplasia induced by disturbed flow. Modulation of identified targets may have protective effects on arterial grafts.

Developmental heterogeneity of vascular cells: Insights into cellular plasticity in atherosclerosis?

Smooth muscle cells, endothelial cells and macrophages display remarkable heterogeneity within the healthy vasculature and under pathological conditions. During development, these cells arise from numerous embryological origins, which confound with different microenvironments to generate postnatal vascular cell diversity. In the atherosclerotic plaque milieu, all these cell types exhibit astonishing plasticity, generating a variety of plaque burdening or plaque stabilizing phenotypes. And yet how developmental origin influences intraplaque cell plasticity remains largely unexplored despite evidence suggesting this may be the case. Uncovering the diversity and plasticity of vascular cells is being revolutionized by unbiased single cell whole transcriptome analysis techniques that will likely continue to pave the way for therapeutic research. Cellular plasticity is only just emerging as a target for future therapeutics, and uncovering how intraplaque plasticity differs across vascular beds may provide key insights into why different plaques behave differently and may confer different risks of subsequent cardiovascular events.

The multi-protective effect of IL-37-Smad3 against ox-LDL induced dysfunction of endothelial cells

Atherosclerosis is a lipid-driven inflammatory arterial disease, with one crucial factor is oxidized low-density lipoprotein (ox-LDL), which can induce endothelial dysfunction through endoplasmic reticulum stress (ERS). Interleukin-37 (IL-37) exerts vascular protective functions. This study aims to investigates whether IL-37 can alleviate ERS and autophagy induced by ox-LDL, therely potentialy treating atherosclerosis. We found that ox-LDL enhances the wound healing rate in Rat Coronary Artery Endothelial Cells (RCAECs) and IL-37 reduce the ox-LDL-induced pro-osteogenic response, ERS, and autophagy by binding to Smad3. In RCAECs treated with ox-LDL and recombinant human IL-37, the wound healing rate was mitigated. The expression of osteogenic transcription factors and proteins involved in the ERS pathway was reduced in the group pretreated with IL-37 and ox-LDL. However, these responses were not alleviated when Smads silenced. Electron microscopy revealed that the IL-37/Smad3 complex could suppress endoplasmic reticulum autophagy under ox-LDL stimulation. Thus, IL-37 might treat atherosclerosis through its multi-protective effect by binding Smad3.

An emerging class of new therapeutics targeting TGF, Activin, and BMP ligands in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an often fatal condition, the primary pathology of which involves loss of pulmonary vascular perfusion due to progressive aberrant vessel remodeling. The reduced capacity of the pulmonary circulation places increasing strain on the right ventricle of the heart, leading to death by heart failure. Currently, licensed therapies are primarily vasodilators, which have increased the median post-diagnosis life expectancy from 2.8 to 7 years. Although this represents a substantial improvement, the search continues for transformative therapeutics that reverse established disease. The genetics of human PAH heavily implicates reduced endothelial bone morphogenetic protein (BMP) signaling as a causal role for the disease pathobiology. Recent approaches have focused on directly enhancing BMP signaling or removing the inhibitory influence of pathways that repress BMP signaling. In this critical commentary, we review the evidence underpinning the development of two approaches: BMP-based agonists and inhibition of activin/GDF signaling. We also address the key considerations and questions that remain regarding these approaches.

Vitamin D Receptor Expression Limits the Angiogenic and Inflammatory Properties of Retinal Endothelial Cells

The integrity of retinal endothelial cell (EC) is essential for establishing and maintaining the retinal blood barrier to ensure proper vision. Vitamin D is a hormone with known protective roles in EC function. The majority of vitamin D action is mediated through the vitamin D receptor (VDR). VDR is a nuclear receptor whose engagement by vitamin D impacts the expression of many genes with important roles in regulation of angiogenesis and inflammation. Although many studies have investigated vitamin D-VDR action in cardiovascular protection and tumor angiogenesis, its impact on retinal EC function and regulation of ocular angiogenesis and inflammation is exceedingly limited. We previously showed calcitriol, the active form of vitamin D, is a potent inhibitor of retinal neovascularization in vivo and retinal EC capillary morphogenesis in vitro. Here, using retinal EC prepared from wild-type (Vdr+/+) and VDR-deficient (Vdr-/-) mice, we show that retinal EC express VDR and its expression is induced by calcitriol. The lack of VDR expression had a significant impact on endothelial cell-cell and cell-matrix interactions. Vdr-/- retinal EC proliferated at a slower rate and were more adherent and less migratory. They also exhibited increased expression levels of inflammatory markers driven in part by sustained activation of STAT1 and NF-κB pathways and were more sensitive to oxidative challenge. These changes were attributed, in part, to down-regulation of endothelial nitric oxide synthetase, enhanced hepcidin expression, and increased intracellular iron levels. Taken together, our results indicate that VDR expression plays a fundamental role in maintaining the proper angiogenic and inflammatory state of retinal EC.

Insights into bone morphogenetic proteins in cardiovascular diseases

Bone morphogenetic proteins (BMPs) are secretory proteins belonging to the transforming growth factor-β (TGF-β) superfamily. These proteins play important roles in embryogenesis, bone morphogenesis, blood vessel remodeling and the development of various organs. In recent years, as research has progressed, BMPs have been found to be closely related to cardiovascular diseases, especially atherosclerosis, vascular calcification, cardiac remodeling, pulmonary arterial hypertension (PAH) and hereditary hemorrhagic telangiectasia (HHT). In this review, we summarized the potential roles and related mechanisms of the BMP family in the cardiovascular system and focused on atherosclerosis and PAH.

Association between fibrinogen/albumin ratio and severity of coronary artery calcification in patients with chronic kidney disease: a retrospective study

Aim

Previous studies have shown that the fibrinogen to albumin ratio (FAR) is closely related to the severity and prognosis of coronary atherosclerosis. In this study, we sought to evaluate the association between FAR and the degree of coronary artery calcification (CAC) in patients with chronic kidney disease (CKD).

Methods

In this retrospective study, 218 patients with CKD were stratified into low, medium and high FAR groups according to the tertiles of the FAR values. The CAC scores, clinical information and laboratory test results of the three FAR groups were compared. To explore the relationship between FAR and CAC we conducted binary logistic regression and correlation analyses.

Results

In the low FAR group, the CAC scores were significantly lower than those in the medium and high FAR groups (P  <  0.001). There was a significant correlation between the FAR and CAC scores (r = 0.510, P  <  0.001). The FAR was an independent predictor of CAC (OR = 1.106, 95% CI [1.004-1.218], P = 0.042).

Conclusion

In patients with CKD, the FAR can be considered as an effective predictor of CAC.

Insights Into the Role of Mitochondria in Vascular Calcification

Vascular calcification (VC) is a growing burden in aging societies worldwide, and with a significant increase in all-cause mortality and atherosclerotic plaque rupture, it is frequently found in patients with aging, diabetes, atherosclerosis, or chronic kidney disease. However, the mechanism of VC is still not yet fully understood, and there are still no effective therapies for VC. Regarding energy metabolism factories, mitochondria play a crucial role in maintaining vascular physiology. Discoveries in past decades signifying the role of mitochondrial homeostasis in normal physiology and pathological conditions led to tremendous advances in the field of VC. Therapies targeting basic mitochondrial processes, such as energy metabolism, damage in mitochondrial DNA, or free-radical generation, hold great promise. The remarkably unexplored field of the mitochondrial process has the potential to shed light on several VC-related diseases. This review focuses on current knowledge of mitochondrial dysfunction, dynamics anomalies, oxidative stress, and how it may relate to VC onset and progression and discusses the main challenges and prerequisites for their therapeutic applications.

Iron disorders and hepcidin

Iron is an essential element due to its role in a wide variety of physiological processes. Iron homeostasis is crucial to prevent iron overload disorders as well as iron deficiency anemia. The liver synthesized peptide hormone hepcidin is a master regulator of systemic iron metabolism. Given its role in overall health, measurement of hepcidin can be used as a predictive marker in disease states. In addition, hepcidin-targeting drugs appear beneficial as therapeutic agents. This review emphasizes recent development on analytical techniques (immunochemical, mass spectrometry and biosensors) and therapeutic approaches (hepcidin agonists, stimulators and antagonists). These insights highlight hepcidin as a potential biomarker as well as an aid in the development of new drugs for iron disorders.

Endothelial to Mesenchymal Transition: An Insight in Atherosclerosis

Atherosclerosis is a fundamental disease of the cardiovascular system that leads to high morbidity and mortality worldwide. The endothelium is the first protective barrier in atherosclerosis. Endothelial cells have the potential to be transformed into mesenchymal cells, in a process termed endothelial to mesenchymal transition (EndMT). On the one hand, EndMT is known to contribute to atherosclerosis by inducing a number of phenotypes ranging from endothelial cell dysfunction to plaque formation. On the other hand, risk factors for atherosclerosis can lead to EndMT. A substantial body of evidence has suggested that EndMT induces the development of atherosclerosis; therefore, a deeper understanding of the molecular mechanisms underlying EndMT in atherosclerosis might provide insights to reverse this condition.

EndMT: Potential Target of H2S against Atherosclerosis

Atherosclerosis is a chronic arterial wall illness that forms atherosclerotic plaques within the arteries. Plaque formation and endothelial dysfunction are atherosclerosis' characteristics. It is believed that the occurrence and development of atherosclerosis mainly include endothelial cell damage, lipoprotein deposition, inflammation and fibrous cap formation, but its molecular mechanism has not been elucidated. Therefore, protecting the vascular endothelium from damage is one of the key factors against atherosclerosis. The factors and processes involved in vascular endothelial injury are complex. Finding out the key factors and mechanisms of atherosclerosis caused by vascular endothelial injury is an important target for reversing and preventing atherosclerosis. Changes in cell adhesion are the early characteristics of EndMT, and cell adhesion is related to vascular endothelial injury and atherosclerosis. Recent researches have exhibited that endothelial-mesenchymal transition (EndMT) can urge atherosclerosis' progress, and it is expected that inhibition of EndMT will be an object for anti-atherosclerosis. We speculate whether inhibition of EndMT can become an effective target for reversing atherosclerosis by improving cell adhesion changes and vascular endothelial injury. Studies have shown that H₂S has a strong cardiovascular protective effect. As H₂S has anti- inflammatory, anti-oxidant, inhibiting foam cell formation, regulating ion channels and enhancing cell adhesion and endothelial functions, the current research on H₂S in cardiovascular aspects is increasing, but anti-atherosclerosis's molecular mechanism and the function of H2S in EndMT have not been explicit. In order to explore the mechanism of H₂S against atherosclerosis, to find an effective target to reverse atherosclerosis, we sum up the progress of EndMT promoting atherosclerosis, and Hydrogen sulfide's potential anti- EndMT effect is discussed in this review.

Contributions of the Endothelium to Vascular Calcification

Vascular calcification (VC) increases morbidity and mortality and constitutes a significant obstacle during percutaneous interventions and surgeries. On a cellular and molecular level, VC is a highly regulated process that involves abnormal cell transitions and osteogenic differentiation, re-purposing of signaling pathways normally used in bone, and even formation of osteoclast-like cells. Endothelial cells have been shown to contribute to VC through a variety of means. This includes direct contributions of osteoprogenitor cells generated through endothelial-mesenchymal transitions in activated endothelium, with subsequent migration into the vessel wall. The endothelium also secretes pro-osteogenic growth factors, such as bone morphogenetic proteins, inflammatory mediators and cytokines in conditions like hyperlipidemia, diabetes, and renal failure. High phosphate levels caused by renal disease have deleterious effects on the endothelium, and induction of tissue non-specific alkaline phosphatase adds to the calcific process. Furthermore, endothelial activation promotes proteolytic destruction of the internal elastic lamina that serves, among other things, as a stabilizer of the endothelium. Appropriate bone mineralization is highly dependent on active angiogenesis, but it is unclear whether the same relationship exists in VC. Through its location facing the vascular lumen, the endothelium is the first to encounter circulating factor and bone marrow-derived cells that might contribute to osteoclast-like versus osteoblast-like cells in the vascular wall. In the same way, the endothelium may be the easiest target to reach with treatments aimed at limiting calcification. This review provides a brief summary of the contributions of the endothelium to VC as we currently know them.

Sox9 and Rbpj differentially regulate endothelial to mesenchymal transition and wound scarring in murine endovascular progenitors

Endothelial to mesenchymal transition (EndMT) is a leading cause of fibrosis and disease, however its mechanism has yet to be elucidated. The endothelium possesses a profound regenerative capacity to adapt and reorganize that is attributed to a population of vessel-resident endovascular progenitors (EVP) governing an endothelial hierarchy. Here, using fate analysis, we show that two transcription factors SOX9 and RBPJ specifically affect the murine EVP numbers and regulate lineage specification. Conditional knock-out of Sox9 from the vasculature (Sox9^fl/fl/Cdh5-Cre^ERRosaYFP) depletes EVP while enhancing Rbpj expression and canonical Notch signalling. Additionally, skin wound analysis from Sox9 conditional knock-out mice demonstrates a significant reduction in pathological EndMT resulting in reduced scar area. The converse is observed with Rbpj conditionally knocked-out from the murine vasculature (Rbpj^fl/fl/Cdh5-CreER RosaYFP) or inhibition of Notch signaling in human endothelial colony forming cells, resulting in enhanced Sox9 and EndMT related gene (Snail, Slug, Twist1, Twist2, TGF-β) expression. Similarly, increased endothelial hedgehog signaling (Ptch1^fl/fl/Cdh5-CreER RosaYFP), that upregulates the expression of Sox9 in cells undergoing pathological EndMT, also results in excess fibrosis. Endothelial cells transitioning to a mesenchymal fate express increased Sox9, reduced Rbpj and enhanced EndMT. Importantly, using topical administration of siRNA against Sox9 on skin wounds can substantially reduce scar area by blocking pathological EndMT. Overall, here we report distinct fates of EVPs according to the relative expression of Rbpj or Notch signalling and Sox9, highlighting their potential plasticity and opening exciting avenues for more effective therapies in fibrotic diseases.

How endothelial to mesenchymal transition is regulated in endovascular progenitors is unclear. Here, the authors show that blocking Sox9 expression in murine endovascular progenitors regulates this transition on skin wounding, affecting the size of scarring, with changes in Rbpj having the opposite effect.

The Cell Origin and Role of Osteoclastogenesis and Osteoblastogenesis in Vascular Calcification

Arterial calcification refers to the abnormal deposition of calcium salts in the arterial wall, which results in vessel lumen stenosis and vascular remodeling. Studies increasingly show that arterial calcification is a cell mediated, reversible and active regulated process similar to physiological bone mineralization. The osteoblasts and chondrocytes-like cells are present in large numbers in the calcified lesions, and express osteogenic transcription factor and bone matrix proteins that are known to initiate and promote arterial calcification. In addition, osteoclast-like cells have also been detected in calcified arterial walls wherein they possibly inhibit vascular calcification, similar to the catabolic process of bone mineral resorption. Therefore, tilting the balance between osteoblast-like and osteoclast-like cells to the latter maybe a promising therapeutic strategy against vascular calcification. In this review, we have summarized the current findings on the origin and functions of osteoblast-like and osteoclast-like cells in the development and progression of vascular progression, and explored novel therapeutic possibilities.

The cardiovascular-dialysis nexus: the transition to dialysis is a treacherous time for the heart

Chronic kidney disease (CKD) patients require dialysis to manage the progressive complications of uraemia. Yet, many physicians and patients do not recognize that dialysis initiation, although often necessary, subjects patients to substantial risk for cardiovascular (CV) death. While most recognize CV mortality risk approximately doubles with CKD the new data presented here show that this risk spikes to >20 times higher than the US population average at the initiation of chronic renal replacement therapy, and this elevated CV risk continues through the first 4 months of dialysis. Moreover, this peak reflects how dialysis itself changes the pathophysiology of CV disease and transforms its presentation, progression, and prognosis. This article reviews how dialysis initiation modifies the interpretation of circulating biomarkers, alters the accuracy of CV imaging, and worsens prognosis. We advocate a multidisciplinary approach and outline the issues practitioners should consider to optimize CV care for this unique and vulnerable population during a perilous passage.

Phenotypic Modulation of Macrophages and Vascular Smooth Muscle Cells in Atherosclerosis-Nitro-Redox Interconnections

Monocytes/macrophages and vascular smooth muscle cells (vSMCs) are the main cell types implicated in atherosclerosis development, and unlike other mature cell types, both retain a remarkable plasticity. In mature vessels, differentiated vSMCs control the vascular tone and the blood pressure. In response to vascular injury and modifications of the local environment (inflammation, oxidative stress), vSMCs switch from a contractile to a secretory phenotype and also display macrophagic markers expression and a macrophagic behaviour. Endothelial dysfunction promotes adhesion to the endothelium of monocytes, which infiltrate the sub-endothelium and differentiate into macrophages. The latter become polarised into M1 (pro-inflammatory), M2 (anti-inflammatory) or Mox macrophages (oxidative stress phenotype). Both monocyte-derived macrophages and macrophage-like vSMCs are able to internalise and accumulate oxLDL, leading to formation of “foam cells” within atherosclerotic plaques. Variations in the levels of nitric oxide (NO) can affect several of the molecular pathways implicated in the described phenomena. Elucidation of the underlying mechanisms could help to identify novel specific therapeutic targets, but to date much remains to be explored. The present article is an overview of the different factors and signalling pathways implicated in plaque formation and of the effects of NO on the molecular steps of the phenotypic switch of macrophages and vSMCs.

Role of crosstalk between endothelial cells and smooth muscle cells in vascular calcification in chronic kidney disease

Chronic kidney disease (CKD) is a severe health problem worldwide, and vascular calcification (VC) contributes substantially to the cardiovascular morbidity and high mortality of CKD. CKD is often accompanied by a variety of pathophysiological states, such as inflammation, oxidative stress, hyperglycaemia, hyperparathyroidism and haemodynamic derangement, that can cause injuries to smooth muscle cells (SMCs) and endothelial cells (ECs) to promote VC. Similar to SMCs, whose role has been widely explored in VC, ECs may contribute to VC via osteochondral transdifferentiation, apoptosis, etc. In addition, given their location in the innermost layer of the blood vessel lumen and preferential reception of various pro‐calcification stimuli, ECs can pass messages to vascular wall cells and communicate with them. Crosstalk between ECs and SMCs via cytokines through a paracrine mechanism, extracellular vesicles, miRNAs and myoendothelial gap junctions also plays a role in VC. In this review, we emphasize the role of intercellular crosstalk between ECs and SMCs in VC associated with CKD.

Pyrogallol-Phloroglucinol-6 6-Bieckol on Attenuates High-Fat Diet-Induced Hypertension by Modulating Endothelial-to-Mesenchymal Transition in the Aorta of Mice

Endothelial-to-mesenchymal transition (EndMT), which is involved in the development of various cardiovascular diseases, is induced by dyslipidemia or obesity. In dyslipidemia, the increased levels of oxidized low-density lipoproteins (oxLDL) upregulated the lectin-type oxidized LDL receptor 1 (Lox-1), which then upregulated the down signaling pathways of PKC-α/MMPs/TGF-β/SMAD2 or 3 and increased the EndMT. In this study, we investigated the effect of pyrogallol-phloroglucinol-6,6-bieckol (PPB), which is a compound of Ecklonia cava (E. cava), on decreased blood pressure (BP) by attenuating the EndMT in a high-fat diet- (HFD-) fed animal model. We also investigated PPB's attenuation effect on EndMT in oxLDL-treated mouse endothelial cells as an in vitro model. The results indicated that, in the aorta or endothelial cells of mice, the HFD or oxLDL treatment significantly increased the expression of Lox-1/PKC-α/MMP9/TGF-β/SMAD2/SMAD3. The PPB treatment significantly decreased its expression. In contrast, the HFD or oxLDL treatment significantly decreased the expression of the EC markers (PECAM-1 and vWF) while the PPB treatment significantly increased them. Moreover, the HFD or oxLDL treatment significantly increased the expression of the mesenchymal cell markers (α-SMA and vimentin) while PPB treatment significantly decreased them. PPB decreased the intima-media thickness and extracellular matrix amount of the aorta and attenuated the BP, which was increased by the HFD. In conclusion, PPB attenuated the upregulation of Lox-1/PKC-α/MMP9/TGF-β/SMAD2 and 3 and restored the EndMT in HFD-fed animals. Moreover, PPB showed a restoring effect on HFD-induced hypertension.

The role of bone morphogenetic protein signaling in vascular calcification

Vascular calcification is associated with atherosclerosis, chronic kidney disease, and diabetes, and results from processes resembling endochondral or intramembranous ossification, or from processes that are distinct from ossification. Bone morphogenetic proteins (BMP), as well as other ligands, receptors, and regulators of the transforming growth factor beta (TGFβ) family regulate vascular and valvular calcification by modulating the phenotypic plasticity of multipotent progenitor lineages associated with the vasculature or valves. While osteogenic ligands BMP2 and BMP4 appear to be both markers and drivers of vascular calcification, particularly in atherosclerosis, BMP7 may serve to protect against calcification in chronic kidney disease. BMP signaling regulators such as matrix Gla protein and BMP-binding endothelial regulator protein (BMPER) play protective roles in vascular calcification. The effects of BMP signaling molecules in vascular calcification are context-dependent, tissue-dependent, and cell-type specific. Here we review the current knowledge on mechanisms by which BMP signaling regulates vascular calcification and the potential therapeutic implications.

The 14-3-3η/GSK-3β/β-catenin complex regulates EndMT induced by 27-hydroxycholesterol in HUVECs and promotes the migration of breast cancer cells

Endothelial-mesenchymal transition (EndMT) is the transformation of endothelial cell morphology to mesenchymal cell morphology, accompanied by decline of endothelial function and enhancement of mesenchymal function, which promotes tumor progression and tumor cell invasion and metastasis. 27-Hydroxycholesterol (27-HC) is a cholesterol metabolite, which has a high content in human blood. 27-HC promotes breast cancer cell proliferation, invasion, and migration. We previously showed that 27-HC promotes EndMT; however, the underlying mechanism still needs to be further explored. We studied the role of the 14-3-3η/GSK-3β/β-catenin complex in EndMT. Our results show that 27-HC induces oxidative stress in HUVECs and activates the p38 signaling pathway, thereby inhibiting the binding of 14-3-3η/GSK-3β/β-catenin, promoting the increase of free β-catenin and nuclear translocation, and finally inducing EndMT. Treatment with N-acetylcysteine (NAC) blocked 27-HC-induced ROS generation and p38 signaling pathway activation, prevented β-catenin from release from binding, and inhibited EndMT. Blocking ROS production or p38 signaling or knocking down 14-3-3η inhibited 27-HC-induced EndMT and inhibited breast cancer cell metastasis. These findings indicate 14-3-3η is necessary for interactions between the p38 kinase and the GSK-3β/β-catenin complex and serves as an adaptor to transmit the upstream kinase signal to the downstream signal, thereby promoting EndMT and breast cancer cell migration.

The Phosphodiesterase-5 Inhibitor Vardenafil Improves the Activation of BMP Signaling in Response to Hydrogen Peroxide

PURPOSE

The pleiotropic roles of phosphodiesterase-5 inhibitors (PDE5is) in cardiovascular diseases have attracted attention. The effect of vardenafil (a PDE5i) is partly mediated through reduced oxidative stress, but it is unclear whether vardenafil protects against hydrogen peroxide (H₂O₂)-induced endothelial cell injury, and the molecular mechanisms that are involved remain unknown. We determined the protective role of vardenafil on H₂O₂-induced endothelial cell injury in cultured human umbilical vein endothelial cells (HUVECs).

METHODS AND RESULTS

Vardenafil decreased the number of TUNEL-positive cells, increased the Bcl2/Bax ratio, and ameliorated the numbers of BrdU-positive cells in H₂O₂-treated HUVECs. The bone morphogenetic protein receptor (BMPR)/p-Smad/MSX2 pathway was enhanced in response to H₂O₂, and vardenafil treatment could normalize this pathway. To determine whether the BMP pathway is involved, we blocked the BMP pathway using dorsomorphin, which abolished the protective effects of vardenafil. We found that vardenafil improved the H₂O₂-induced downregulation of BMP-binding endothelial regulator protein (BMPER), which possibly intersects with the BMP pathway in the regulation of endothelial cell injury in response to oxidative stress.

CONCLUSIONS

We demonstrated for the first time that exogenous H₂O₂ activates BMPR expression and promotes Smad1/5/8 phosphorylation. Additionally, vardenafil can attenuate H₂O₂-induced endothelial cell injury in HUVECs. Vardenafil decreases apoptosis through an improved Bcl-2/Bax ratio and increases cell proliferation. Vardenafil protects against endothelial cell injury through ameliorating the intracellular oxidative stress level and BMPER expression. The protective role of vardenafil on H₂O₂-induced endothelial cell injury is mediated through BMPR/p-Smad/MSX2 in HUVECs.

Msx2 plays an important role in BMP6-induced osteogenic differentiation of two mesenchymal cell lines: C3H10T1/2 and C2C12

Bone morphogenetic proteins (BMPs), have been shown to enhance the osteogenic differentiation of mesenchymal cells (MCs) and to promote bone formation. BMP6 is known to play an important role in the process of MCs towards osteogenic differentiation by virtue of their osteoinductive and cell type specific proliferative activity. However, the molecular mechanism relate to BMP6 osteoinductive activity is still unclear and continues to warrant further investigation. Msx2 is a member of the homeobox gene family of transcription factors and promotes calcification. Hence, we wondered if it might also play a role in BMP6-induced osteogenesis. In this study, two mouse mesenchymal cell lines were treated with BMP6, adenovirus-Msx2 (Ad-Msx2) or adenovirus-siMsx2 (Ad-siMsx2). Based on the results of mRNA and protein expression, it was indicated that BMP6 could enhance the expression of Msx2 and activate the phosphorylation of Smad 1/5/8, p38 and ERK1/2. Being transfected by Ad-Msx2, the BMP6-induced activation of phosphorylation was significantly promoted. On the contrary, two cell lines transfected by Ad-siMsx2 presented an inhibited expression of three phosphorylated proteins even after being induced by BMP6. The evaluation of ALP, OPN, OC and calcium deposits revealed the osteogenic results those were corresponding to the results of mRNA and protein. Taken together, these findings can be a novel viewpoint for the understanding of the mechanisms of BMP6-induced osteogenesis and provide therapeutic targets of bone defect.

An overview of the mechanisms in vascular calcification during chronic kidney disease

PURPOSE OF REVIEW

Chronic kidney disease (CKD) facilitates a unique environment to strongly accelerate vascular calcification - the pathological deposition of calcium-phosphate in the vasculature. These calcifications are associated with the excessive cardiovascular mortality of CKD patients.

RECENT FINDINGS

Vascular calcification is a multifaceted active process, mediated, at least partly, by vascular smooth muscle cells. These cells are able to transdifferentiate into cells with osteo/chondrogenic properties, which exert multiple effects to facilitate vascular tissue mineralization. As the understanding of the underlying pathophysiology increases, first therapeutic concepts begin to emerge.

SUMMARY

This brief review provides an overview on the so far known mechanisms involved in the initiation and progression of vascular calcification in CKD.

Interplay between BMPs and Reactive Oxygen Species in Cell Signaling and Pathology

The integration of cell extrinsic and intrinsic signals is required to maintain appropriate cell physiology and homeostasis. Bone morphogenetic proteins (BMPs) are cytokines that belong to the transforming growth factor-β (TGF-β) superfamily, which play a key role in embryogenesis, organogenesis and regulation of whole-body homeostasis. BMPs interact with membrane receptors that transduce information to the nucleus through SMAD-dependent and independent pathways, including PI3K-AKT and MAPKs. Reactive oxygen species (ROS) are intracellular molecules derived from the partial reduction of oxygen. ROS are highly reactive and govern cellular processes by their capacity to regulate signaling pathways (e.g., NF-κB, MAPKs, KEAP1-NRF2 and PI3K-AKT). Emerging evidence indicates that BMPs and ROS interplay in a number of ways. BMPs stimulate ROS production by inducing NOX expression, while ROS regulate the expression of several BMPs. Moreover, BMPs and ROS influence common signaling pathways, including PI3K/AKT and MAPK. Additionally, dysregulation of BMPs and ROS occurs in several pathologies, including vascular and musculoskeletal diseases, obesity, diabetes and kidney injury. Here, we review the current knowledge on the integration between BMP and ROS signals and its potential applications in the development of new therapeutic strategies.

A Brief Review about the Role of Nanomaterials, Mineral-Organic Nanoparticles, and Extra-Bone Calcification in Promoting Carcinogenesis and Tumor Progression

People come in contact with a huge number of nanoparticles (NPs) throughout their lives, which can be of both natural and anthropogenic origin and are capable of entering the body through swallowing, skin penetration, or inhalation. In connection with the expanding use of nanomaterials in various industrial processes, the question of whether there is a need to study the potentially adverse effects of NPs on human health becomes increasingly important. Despite the fact that the nature and the extent of damage caused depends on the chemical and the physical characteristics of individual NPs, there are also general mechanisms related to their toxicity. These mechanisms include the ability of NPs to translocate to various organs through endocytosis, as well as their ability to stimulate the production of reactive oxygen species (ROS), leading to oxidative stress, inflammation, genotoxicity, metabolic changes, and potentially carcinogenesis. In this review, we discuss the main characteristics of NPs and the effects they cause at both cellular and tissue levels. We also focus on possible mechanisms that underlie the relationship of NPs with carcinogenesis. We briefly summarize the main concepts related to the role of endogenous mineral organic NPs in the development of various human diseases and their participation in extra-bone calcification. Considering data from both our studies and those published in scientific literature, we propose the revision of some ideas concerning extra-bone calcification, since it may be one of the factors associated with the initiation of the mechanisms of immunological tolerance.

Oxidized HDL, as a Novel Biomarker for Calcific Aortic Valve Disease, Promotes the Calcification of Aortic Valve Interstitial Cells

Calcific aortic valve disease (CAVD) is characterized by progressive mineralization of the aortic valve. Lipid infiltration and oxidative stress are the driving forces for the initiation and development of this disease. However, it remains unknown whether oxidized high-density lipoprotein (ox-HDL) plays a role in the mineralization of aortic valve interstitial cells (AVICs). Serum ox-HDL levels were determined in 168 severe CAVD patients and 168 age- and gender-matched non-CAVD controls. Results showed that ox-HDL concentrations were significantly increased in CAVD compared with the control group (131.52 ± 30.96 ng/mL vs. 112.58 ± 32.20 ng/mL, P < 0.001) and were correlated with CAVD severity. Multivariable logistic regression revealed that ox-HDL levels were independently associated with CAVD after adjusting for the incidence of coronary artery disease (CAD) (odds ratio 1.019, 95% CI 1.012-1.027, P < 0.001) or atherosclerotic risk factors (odds ratio 1.027, 95% CI 1.017-1.037, P < 0.001). Chronic ox-HDL stimulation of AVICs increased alkaline phosphatase activity (ALP) and calcium deposits in AVICs in vitro. Mechanistic studies further showed that ox-HDL upregulated several osteogenic factors, including BMP-2, Runx2, and Msx2 expressions in AVICs. This is the first study to demonstrate a relationship between increased ox-HDL concentration and CAVD incidence.

Severe Heterotopic Ossification in the Skeletal Muscle and Endothelial Cells Recruitment to Chondrogenesis Are Enhanced by Monocyte/Macrophage Depletion

Altered macrophage infiltration upon tissue damage results in inadequate healing due to inappropriate remodeling and stem cell recruitment and differentiation. We investigated in vivo whether cells of endothelial origin phenotypically change upon heterotopic ossification induction and whether infiltration of innate immunity cells influences their commitment and alters the ectopic bone formation. Liposome-encapsulated clodronate was used to assess macrophage impact on endothelial cells in the skeletal muscle upon acute damage in the ECs specific lineage-tracing Cdh5CreER^T2:R26REYFP/dtTomato transgenic mice. Macrophage depletion in the injured skeletal muscle partially shifts the fate of ECs toward endochondral differentiation. Upon ectopic stimulation of BMP signaling, monocyte depletion leads to an enhanced contribution of ECs chondrogenesis and to ectopic bone formation, with increased bone volume and density, that is reversed by ACVR1/SMAD pathway inhibitor dipyridamole. This suggests that macrophages contribute to preserve endothelial fate and to limit the bone lesion in a BMP/injury-induced mouse model of heterotopic ossification. Therefore, alterations of the macrophage-endothelial axis may represent a novel target for molecular intervention in heterotopic ossification.

SOX Transcription Factors in Endothelial Differentiation and Endothelial-Mesenchymal Transitions

The SRY (Sex Determining Region Y)-related HMG box of DNA binding proteins, referred to as SOX transcription factors, were first identified as critical regulators of male sex determination but are now known to play an important role in vascular development and disease. SOX7, 17, and 18 are essential in endothelial differentiation and SOX2 has emerged as an essential mediator of endothelial-mesenchymal transitions (EndMTs), a mechanism that enables the endothelium to contribute cells with abnormal cell differentiation to vascular disease such as calcific vasculopathy. In the following paper, we review published information on the SOX transcription factors in endothelial differentiation and hypothesize that SOX2 acts as a mediator of EndMTs that contribute to vascular calcification.

Bone morphogenetic protein signaling in inflammation

IMPACT STATEMENT

By compiling findings from recent studies, this review will garner novel insight on the dynamic and complex role of BMP signaling in diseases of inflammation, highlighting the specific roles played by both individual ligands and endogenous antagonists. Ultimately, this summary will help inform the high therapeutic value of targeting this pathway for modulating diseases of inflammation.

Pharmacologic Strategies for Assaying BMP Signaling Function

The bone morphogenetic protein (BMP) signaling pathway, a subset of the transforming growth factor β (TGF-β) signaling family, consists of structurally diverse receptors and ligands whose combinatorial specificity encodes autocrine, paracrine, and endocrine signals essential for regulating tissue growth, differentiation, and survival during embryonic patterning and postnatal tissue remodeling. Aberrant signaling of these receptors and ligands is implicated in a variety of inborn and acquired diseases. The roles of various receptors and their ligands can be explored using small molecule inhibitors of the BMP receptor kinases. Several BMP type I receptor kinase inhibitor tool compounds have been described that exhibit sufficient selectivity to discriminate BMP receptor signaling in vitro or in vivo, with various trade-offs in selectivity, potency, cell permeability, and pharmacokinetics. Several methods for assaying BMP function via pharmacologic inhibition are presented. Two in vitro methods, an In-Cell Western assay of BMP-mediated SMAD1/5/8 phosphorylation and an alkaline phosphatase osteogenic differentiation assay, represent efficient high-throughput methodologies for assaying pharmacologic inhibitors. Two in vivo methods are described for assaying the effects of BMP signaling inhibition in embryonic zebrafish and mouse development. Small molecule inhibitors of BMP receptor kinases represent an important complementary strategy to genetic gain- and loss-of-function and ligand-trap approaches for targeting this signaling system in biology and disease.

Influences of Sex and Estrogen in Arterial and Valvular Calcification

Vascular and cardiac valvular calcification was once considered to be a degenerative and end stage product in aging cardiovascular tissues. Over the past two decades, however, a critical mass of data has shown that cardiovascular calcification can be an active and highly regulated process. While the incidence of calcification in the coronary arteries and cardiac valves is higher in men than in age-matched women, a high index of calcification associates with increased morbidity, and mortality in both sexes. Despite the ubiquitous portending of poor outcomes in both sexes, our understanding of mechanisms of calcification under the dramatically different biological contexts of sex and hormonal milieu remains rudimentary. Understanding how the critical context of these variables inform our understanding of mechanisms of calcification-as well as innovative strategies to target it therapeutically-is essential to advancing the fields of both cardiovascular disease and fundamental mechanisms of aging. This review will explore potential sex and sex-steroid differences in the basic biological pathways associated with vascular and cardiac valvular tissue calcification, and potential strategies of pharmacological therapy to reduce or slow these processes.

BMAL1 suppresses ROS-induced endothelial-to-mesenchymal transition and atherosclerosis plaque progression via BMP signaling

Circadian rhythm disruption is intimately linked to atherosclerosis, and endothelial-to-mesenchymal transition (EndMT) is a major feature of atherosclerosis progression and unstable plaques. However, the mechanisms underlying the roles of Brain and Muscle ARNT-Like Protein-1 (BMAL1), an essential clock transcription activator, in EndMT and plaque instability have not been characterized. In the present study, we found a positive relationship among BMAL1 expression loss, EndMT, and plaque vulnerability in human carotid plaques. Furthermore, loss- and gain-of-function studies in human aortic endothelial cells (HAECs) revealed that BMAL1 inhibited oxidized low-density lipoprotein (oxLDL)-induced intracellular reactive oxygen species (ROS) accumulation and subsequent EndMT. Mechanistically, BMAL1 deficiency aggravated EndMT through BMP-mediated signaling. Collectively, our study demonstrates the underlying mechanism for the central role of BMAL1 loss in atherosclerosis progression and plaque stability transition promoted by oxidative stress, which can be targeted therapeutically to prevent the occurrence and progression of atherosclerosis.

Fractionated human adipose tissue as a native biomaterial for the generation of a bone organ by endochondral ossification

Many steps are required to generate bone through endochondral ossification with adipose mesenchymal stromal cells (ASC), from cell isolation to in vitro monolayer expansion, seeding into scaffolds, cartilaginous differentiation and in vivo remodeling. Moreover, monolayer expansion and passaging of ASC strongly decreases their differentiation potential. Here, we propose that adipose tissue itself can be used as scaffold for ASC expansion and endochondral ossification. Human liposuctions were fractionated and cultured for 3 weeks with proliferative medium in suspension. The resulting constructs, named Adiscaf, were compared to constructs generated with a previously developed, control approach, i.e. collagen sponges seeded with monolayer-expanded ASC. After 4 weeks of chondrogenic differentiation, Adiscaf contained cartilage tissue, characterized by glycosaminoglycans and collagen type II. After 2 additional weeks of hypertrophic differentiation, Adiscaf showed upregulation of hypertrophic markers at the gene expression and protein levels. After 8 weeks of in vivo implantation, Adiscaf resulted in ectopic bone tissue formation, including bone marrow elements. Adiscaf showed superior in vitro differentiation and in vivo performance as compared to the control paradigm involving isolation and monolayer expansion of ASC. This new paradigm exploits the physiological niche of adipose tissue and strongly suggests a higher functionality of cells inside adipose tissue after in vitro expansion. This study demonstrates that adult human adipose tissue used as a native construct can generate a bone organ by endochondral ossification. The concept could be exploited for the generation of osteogenic grafts for bone repair.

STATEMENT OF SIGNIFICANCE

In this study we used adult human adipose tissue as scaffolding materials (called Adiscaf) to generate a bone organ by endochondral ossification. Adiscaf concept is based on the culture of adipose tissue cells inside their native microenvironment for the generation of osteogenic grafts for bone repair. This simplified approach overcomes several limitations linked to the current techniques in bone tissue engineering, such as isolation of cells and inadequate properties of the biomaterials used as scaffolds. In addition, the present paradigm proposes to exploit physiological niches in order to better maintain the functionality of cells during their in vitro expansion. This project not only has a scientific impact by evaluating the impact of native physiological niches on the functionality and chondrogenic differentiation of mesenchymal progenitors but also a clinical impact to generate osteogenic grafts and/or osteoinductive materials for bone regeneration and repair.

Oxidized low density lipoprotein induces endothelial-to-mesenchymal transition by stabilizing Snail in human aortic endothelial cells

The endothelial-to-mesenchymal transition (EndMT) of endothelial cells contributes to the development of atherosclerosis. Oxidized low density lipoprotein (ox-LDL) is a highly risk factor for atherosclerosis. However, whether ox-LDL causes EndMT and the underlying mechanism are unclear. We report here that ox-LDL treatment is able to induce EndMT in human aortic endothelial cells (HAECs), and that the ox-LDL-induced EndMT is strictly dependent on the presence of its innate receptor, ox-LDL Receptor-1 (LOX-1). In addition, ox-LDL specifically upregulates EndMT transcriptional factor Snail, and knockdown of Snail completely attenuates ox-LDL-induced EndMT, indicating an essential role of Snail in mediating this effect. Mechanically, ox-LDL induces Snail stabilization by inhibiting its ubiquitination, which is in part attributed to inhibited GSK-3β activity. Hence, our findings suggest that inducing EndMT of aortic endothelial cells by ox-LDL might contribute to its detrimental role in promoting atherosclerosis development.

Wnt11 promotes BMP9-induced osteogenic differentiation through BMPs/Smads and p38 MAPK in mesenchymal stem cells

Bone morphogenetic protein 9 (BMP9), as one of the most potent osteogenic factors, is a promising cytokine for bone tissue engineering. Wnt11 can regulate the development of the skeletal system and is related to high bone mass syndrome. However, the effect of Wnt11 on BMP9-induced osteogenic differentiation remains unknown. In this study, we investigated the relationship between Wnt11- and BMP9-induced osteogenic differentiation in mesenchymal stem cells (MSCs). We recapitulated the osteogenic potential of BMP9 in C3H10T1/2 cells. The messenger RNA expression of Wnt11 is detectable in the available progenitor cells, and BMP9 can obviously increase the protein level of Wnt11 in these cells. Exogenous Wnt11 potentiates the effect of BMP9 on increasing alkaline phosphatase (ALP) activities, the expression of osteopontin (OPN), and Runt-related transcription factor 2 (Runx2), so does matrix mineralization in C3H10T1/2 cells. Although Wnt11 cannot increase the BMP9-induced ectopic bone formation, it can increase the bone density induced by BMP9 apparently. Wnt11 increases the level of p-Smad1/5/8, as well as p-p38. Meanwhile, Wnt11 promotes the effect of BMP9 on increasing the levels of p-Smad1/5/8 and p-p38. Inhibition of p38 decreases the BMP9-induced ALP activities, the expression of OPN, and the mineralization in C3H10T1/2 cells. However, all of these effects of the p38 inhibitor on BMP9-induced osteogenic markers can be almost reversed by the overexpression of Wnt11. Our findings suggested that Wnt11 can enhance the osteogenic potential of BMP9 in MSCs, and this effect may be partly mediated through enhancing BMPs/Smads and the p38 MAPK signal, which was induced by BMP9.

The Role of Renin-Angiotensin-Aldosterone System and Its New Components in Arterial Stiffness and Vascular Aging

Many cardiovascular diseases present renin-angiotensin-aldosterone system (RAAS) hyperactivity as an important pathophysiological mechanism to be target in the therapeutic approaches. Moreover, arterial stiffness is currently considered as a new independent risk factor for cardiovascular disease in different clinical conditions, including hypertension and chronic kidney disease. In fact, excessive stimulation of angiotensin type 1 (AT1) receptors, as well as mineralocorticoid receptors, results in cellular growth, oxidative stress and vascular inflammation, which may lead to arterial stiffness and accelerate the process of vascular aging. In the last decades, a vasoprotective axis of the RAAS has been discovered, and now it is well established that new components with antioxidant and anti-inflammatory properties play important roles promoting vasodilation, natriuresis and reducing collagen deposition, thus attenuating arterial stiffness and improving endothelial function. In this review, we will focus on these pathophysiological mechanisms and the relevance of RAAS inhibition by different strategies to increase arterial compliance and to decelerate vascular aging.

Bone Morphogenetic Proteins in Vascular Homeostasis and Disease

It is well established that control of vascular morphogenesis and homeostasis is regulated by vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), Delta-like 4 (Dll4), angiopoietin, and ephrin signaling. It has become clear that signaling by bone morphogenetic proteins (BMPs), which have a long history of studies in bone and early heart development, are also essential for regulating vascular function. Indeed, mutations that cause deregulated BMP signaling are linked to two human vascular diseases, hereditary hemorrhagic telangiectasia and pulmonary arterial hypertension. These observations are corroborated by data obtained with vascular cells in cell culture and in mouse models. BMPs are required for normal endothelial cell differentiation and for venous/arterial and lymphatic specification. In adult life, BMP signaling orchestrates neo-angiogenesis as well as vascular inflammation, remodeling, and calcification responses to shear and oxidative stress. This review emphasizes the pivotal role of BMPs in the vascular system, based on studies of mouse models and human vascular disorders.

Bone mesenchymal stem cells co-expressing VEGF and BMP-6 genes to combat avascular necrosis of the femoral head

The aim of the present study was to investigate the potential of bone mesenchymal stem cells (BMSCs) treated with a combination of vascular endothelial growth factor (VEGF) and bone morphogenetic protein-6 (BMP-6) genes for the treatment of avascular necrosis of the femoral head (ANFH). Rat BMSCs were isolated and purified using a density gradient centrifugation method. The purity and characteristics of the BMSCs were detected by cell surface antigens identification using flow cytometry. The experimental groups were administered with one of the following adeno-associated virus (AAV) vector constructs: AAV-green fluorescent protein (AAV-GFP), AAV-BMP-6, AAV-VEGF or AAV-VEGF-BMP-6. The expression of VEGF and BMP-6 was detected by reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA assays. The effects of VEGF and BMP-6 on BMSCs were evaluated by angiogenic and osteogenic assays. The transfected BMSCs were combined with a biomimetic synthetic scaffold poly lactide-co-glycolide (PLAGA) and they were then subcutaneously implanted into nude mice. After four weeks, the implants were analyzed with histology and subsequent immunostaining to evaluate the effects of BMSCs on blood vessel and bone formation in vivo. In the AAV-VEGF-BMP-6 group, the expression levels of VEGF and BMP-6 were significantly increased and human umbilical vein endothelial cells tube formation was significantly enhanced compared with other groups. Capillaries and bone formation in the AAV-VEGF-BMP-6 group was significantly higher compared with the other groups. The results of the present study suggest that BMSCs expressing both VEGF and BMP-6 induce an increase in blood vessels and bone formation, which provides theoretical support for ANFH gene therapy.

Vascular scaffolds with enhanced antioxidant activity inhibit graft calcification

There is a need for off-the-shelf, small-diameter vascular grafts that are safe and exhibit high long-term patency. Decellularized tissues can potentially be used as vascular grafts; however, thrombogenic and unpredictable remodeling properties such as intimal hyperplasia and calcification are concerns that hinder their clinical use. The objective of this study was to investigate the long-term function and remodeling of extracellular matrix (ECM)-based vascular grafts composited with antioxidant poly(1, 8-octamethylene-citrate-co-cysteine) (POCC) with or without immobilized heparin. Rat aortas were decellularized to create the following vascular grafts: 1) ECM hybridized with POCC (Poly-ECM), 2) Poly-ECM subsequently functionalized with heparin (Poly-ECM-Hep), and 3) non-modified vascular ECM. Grafts were evaluated as interposition grafts in the abdominal aorta of adult rats at three months. All grafts displayed antioxidant activity, were patent, and exhibited minimal intramural cell infiltration with varying degrees of calcification. Areas of calcification co-localized with osteochondrogenic differentiation of vascular smooth muscle cells, lipid peroxidation, oxidized DNA damage, and cell apoptosis, suggesting an important role for oxidative stress in the calcification of grafts. The extent of calcification within grafts was inversely proportional to their antioxidant activity: Poly-ECM-Hep > ECM > Poly-ECM. The incorporation of antioxidants into vascular grafts may be a viable strategy to inhibit degenerative changes.

Bone morphogenetic protein 9 (BMP9) and BMP10 enhance tumor necrosis factor-α-induced monocyte recruitment to the vascular endothelium mainly via activin receptor-like kinase 2

Bone morphogenetic proteins 9 and 10 (BMP9/BMP10) are circulating cytokines with important roles in endothelial homeostasis. The aim of this study was to investigate the roles of BMP9 and BMP10 in mediating monocyte-endothelial interactions using an in vitro flow adhesion assay. Herein, we report that whereas BMP9/BMP10 alone had no effect on monocyte recruitment, at higher concentrations both cytokines synergized with tumor necrosis factor-α (TNFα) to increase recruitment to the vascular endothelium. The BMP9/BMP10-mediated increase in monocyte recruitment in the presence of TNFα was associated with up-regulated expression levels of E-selectin, vascular cell adhesion molecule (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1) on endothelial cells. Using siRNAs to type I and II BMP receptors and the signaling intermediaries (Smads), we demonstrated a key role for ALK2 in the BMP9/BMP10-induced surface expression of E-selectin, and both ALK1 and ALK2 in the up-regulation of VCAM-1 and ICAM-1. The type II receptors, BMPR-II and ACTR-IIA were both required for this response, as was Smad1/5. The up-regulation of cell surface adhesion molecules by BMP9/10 in the presence of TNFα was inhibited by LDN193189, which inhibits ALK2 but not ALK1. Furthermore, LDN193189 inhibited monocyte recruitment induced by TNFα and BMP9/10. BMP9/10 increased basal IκBα protein expression, but did not alter p65/RelA levels. Our findings suggest that higher concentrations of BMP9/BMP10 synergize with TNFα to induce the up-regulation of endothelial selectins and adhesion molecules, ultimately resulting in increased monocyte recruitment to the vascular endothelium. This process is mediated mainly via the ALK2 type I receptor, BMPR-II/ACTR-IIA type II receptors, and downstream Smad1/5 signaling.

Macrophage-derived foam cells impair endothelial barrier function by inducing endothelial-mesenchymal transition via CCL-4

Recently, endothelial-mesenchymal transition (EndMT) has been demonstrated to play an important role in the development of atherosclerosis, the molecular mechanisms of which remain unclear. In the present study, scanning electron microscopy directly revealed a widened endothelial space and immunohistofluorescence demonstrated that EndMT was increased in human aorta atherosclerotic plaques. M1 macrophage-derived foam cell (M1-FC) supernatants, but not M2 macrophage-derived foam cell (M2-FC) supernatants, induced EndMT. A protein array and enzyme-linked immunosorbent assay identified that the levels of several cytokines, including C-C motif chemokine ligand 4 (CCL-4) were increased in M1-FC supernatants, in which EndMT was promoted, accompanied by increased endothelial permeability and monocyte adhesion. Furthermore, anti-CCL-4 antibody abolished the effects of M1-FC supernatants on EndMT. At the same time, CCL-4 activated its receptor, C-C motif chemokine receptor-5 (CCR-5), and upregulated transforming growth factor-β (TGF-β) expression. Further experiments revealed that EndMT induced by CCL-4 was reversed by treatment with CCR-5 antagonist and the RNA-mediated knockdown of TGF-β. On the whole, the data of the present study suggest that M1-FCs induce EndMT by upregulating CCL-4, and increase endothelial permeability and monocyte adhesion. These data may help to elucidate the important role of EndMT in the development of atherosclerosis.

Endothelial-to-mesenchymal transition: A novel therapeutic target for cardiovascular diseases

Endothelial-to-mesenchymal transition (EndMT) is a complex biological process in which endothelial cells lose their specific markers and acquire a mesenchymal or myofibroblastic phenotype. Similar to epithelial-to-mesenchymal transition (EMT), EndMT can be induced by multiple stimulants such as cytokines and metabolic factors that play crucial roles in the development of the cardiovascular system. Recent studies have demonstrated that EndMT may play a significant role in the pathogenesis of cardiovascular diseases (CVDs), and may represent a novel therapeutic target for cardiovascular remodeling and fibrotic disorders. The exact molecular mechanisms involved in cardiovascular pathogenesis that occur as a result of EndMT, however, are not fully explained. In this review, we reveal the multiple intercellular mechanisms of EndMT including stimulants, signaling pathways, and seek to explore the relationship between this biological process, cardiovascular system development, and CVDs that may lead to new therapeutic strategies for the treatment of CVDs.