Wnt16 attenuates TGFβ-induced chondrogenic transformation in vascular smooth muscle

Vascular Smooth Muscle Cells Transdifferentiate into Chondrocyte-Like Cells and Facilitate Meniscal Fibrocartilage Regeneration

The effective and translational strategy to regenerate knee meniscal fibrocartilage remained challenging. Herein, we first identified vascular smooth muscle cells (VSMCs) transdifferentiated into fibrochondrocytes and participated in spontaneous meniscal regeneration using smooth muscle cell lineage tracing transgenic mice meniscal defect model. Then, we identified low-intensity pulsed ultrasound (LIPUS) acoustic stimulus enhanced fibrochondrogenic transdifferentiation of VSMCs in vitro and in vivo. Mechanistically, LIPUS stimulus could up-regulate mechanosensitive ion channel Piezo1 expression and then activate the transforming growth factor β1 (TGFβ1) signal, following repression of the Notch signal, consequently enhancing fibrochondrogenic transdifferentiation of VSMCs. Finally, we demonstrated that the regular LIPUS stimulus enhanced anisotropic native-like meniscal fibrocartilage tissue regeneration in a beagle canine subtotal meniscectomy model at 6 months postoperatively. The single-cell RNA sequencing analysis confirmed the role of VSMC fibrochondrogenic transdifferentiation in meniscal regeneration.

Genetic basis of right and left ventricular heart shape

Heart shape captures variation in cardiac structure beyond traditional phenotypes of mass and volume. Although observational studies have demonstrated associations with cardiometabolic risk factors and diseases, its genetic basis is less understood. We utilised cardiovascular magnetic resonance images from 45,683 UK Biobank participants to construct a heart shape atlas from bi-ventricular end-diastolic surface mesh models through principal component (PC) analysis. Genome-wide association studies were performed on the first 11 PCs that captured 83.6% of shape variance. We identified 43 significant loci, 14 were previously unreported for cardiac traits. Genetically predicted PCs were associated with cardiometabolic diseases. In particular two PCs (2 and 3) linked with more spherical ventricles being associated with increased risk of atrial fibrillation. Our study explores the genetic basis of multidimensional bi-ventricular heart shape using PCA, reporting new loci and biology, as well as polygenic risk scores for exploring genetic relationships of heart shape with cardiometabolic diseases.

Vascular calcification and cellular signaling pathways as potential therapeutic targets

Increased vascular calcification (VC) is observed in patients with cardiovascular diseases such as atherosclerosis, diabetes, and chronic kidney disease. VC is divided into three types according to its location: intimal, medial, and valvular. Various cellular signaling pathways are associated with VC, including the Wnt, mitogen-activated protein kinase, phosphatidylinositol-3 kinase/Akt, cyclic nucleotide-dependent protein kinase, protein kinase C, calcium/calmodulin-dependent kinase II, adenosine monophosphate-activated protein kinase/mammalian target of rapamycin, Ras homologous GTPase, apoptosis, Notch, and cytokine signaling pathways. In this review, we discuss the literature concerning the key cellular signaling pathways associated with VC and their role as potential therapeutic targets. Inhibitors to these pathways represent good candidates for use as potential therapeutic agents for the prevention and treatment of VC.

Wnt16 Promotes Vascular Smooth Muscle Contractile Phenotype and Function via Taz (Wwtr1) Activation in Male LDLR-/- Mice

Wnt16 is expressed in bone and arteries, and maintains bone mass in mice and humans, but its role in cardiovascular physiology is unknown. We show that Wnt16 protein accumulates in murine and human vascular smooth muscle (VSM). WNT16 genotypes that convey risk for bone frailty also convey risk for cardiovascular events in the Dallas Heart Study. Murine Wnt16 deficiency, which causes postnatal bone loss, also reduced systolic blood pressure. Electron microscopy demonstrated abnormal VSM mitochondrial morphology in Wnt16-null mice, with reductions in mitochondrial respiration. Following angiotensin-II (AngII) infusion, thoracic ascending aorta (TAA) dilatation was greater in Wnt16-/- vs Wnt16+/+ mice (LDLR-/- background). Acta2 (vascular smooth muscle alpha actin) deficiency has been shown to impair contractile phenotype and worsen TAA aneurysm with concomitant reductions in blood pressure. Wnt16 deficiency reduced expression of Acta2, SM22 (transgelin), and other contractile genes, and reduced VSM contraction induced by TGFβ. Acta2 and SM22 proteins were reduced in Wnt16-/- VSM as was Ankrd1, a prototypic contractile target of Yap1 and Taz activation via TEA domain (TEAD)-directed transcription. Wnt16-/- VSM exhibited reduced nuclear Taz and Yap1 protein accumulation. SiRNA targeting Wnt16 or Taz, but not Yap1, phenocopied Wnt16 deficiency, and Taz siRNA inhibited contractile gene upregulation by Wnt16. Wnt16 incubation stimulated mitochondrial respiration and contraction (reversed by verteporfin, a Yap/Taz inhibitor). SiRNA targeting Taz inhibitors Ccm2 and Lats1/2 mimicked Wnt16 treatment. Wnt16 stimulated Taz binding to Acta2 chromatin and H3K4me3 methylation. TEAD cognates in the Acta2 promoter conveyed transcriptional responses to Wnt16 and Taz. Wnt16 regulates cardiovascular physiology and VSM contractile phenotype, mediated via Taz signaling.

Vascular smooth muscle cells in intimal hyperplasia, an update

Arterial occlusive disease is the leading cause of death in Western countries. Core contemporary therapies for this disease include angioplasties, stents, endarterectomies and bypass surgery. However, these treatments suffer from high failure rates due to re-occlusive vascular wall adaptations and restenosis. Restenosis following vascular surgery is largely due to intimal hyperplasia. Intimal hyperplasia develops in response to vessel injury, leading to inflammation, vascular smooth muscle cells dedifferentiation, migration, proliferation and secretion of extra-cellular matrix into the vessel's innermost layer or intima. In this review, we describe the current state of knowledge on the origin and mechanisms underlying the dysregulated proliferation of vascular smooth muscle cells in intimal hyperplasia, and we present the new avenues of research targeting VSMC phenotype and proliferation.

TNFα activation and TGFβ blockage act synergistically for smooth muscle cell calcification in patients with venous thrombosis via TGFβ/ERK pathway

Venous calcification has been observed in post‐thrombotic syndrome (PTS) patients; yet, the cell types and possible mechanisms regulating this process are still unclear. We evaluated the calcium deposition within the venous wall, the cell type involved in the calcified remodelling of the venous wall after thrombosis and explored possible mechanisms in vitro. Calcium deposition was found in human specimens of superficial thrombotic veins and was co‐localized with VSMCs markers αSMA and TAGLN (also known as SM22α). Besides, the expression of osteogenesis‐related genes was dramatically changed in superficial thrombotic veins. Moreover, the inhibition of the TGFβ signalling pathway after TNFα treatment effectively induced the expression of osteogenic phenotype markers, the calcium salt deposits and the obvious phosphorylation of ERK1/2 and JNK2 in the VSMCs calcification model. Supplementing TGFβ2 or blocking the activation of the ERK/MAPK signalling pathway prevented the transformation of VSMCs into osteoblast‐like cells in vitro. Taken together, VSMCs have an important role in venous calcification after thrombosis. Supplementing TGFβ2 or inhibiting the ERK/MAPK signalling pathway can reduce the appearance of VSMCs osteogenic phenotype. Our findings may present a novel therapeutic approach to prevent of vascular calcification after venous thrombosis.

Antifibrotic factor KLF4 is repressed by the miR-10/TFAP2A/TBX5 axis in dermal fibroblasts: insights from twins discordant for systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is a complex disease of unknown aetiology in which inflammation and fibrosis lead to multiple organ damage. There is currently no effective therapy that can halt the progression of fibrosis or reverse it, thus studies that provide novel insights into disease pathogenesis and identify novel potential therapeutic targets are critically needed.

METHODS

We used global gene expression and genome-wide DNA methylation analyses of dermal fibroblasts (dFBs) from a unique cohort of twins discordant for SSc to identify molecular features of this pathology. We validated the findings using in vitro, ex vivo and in vivo models.

RESULTS

Our results revealed distinct differentially expressed and methylated genes, including several transcription factors involved in stem cell differentiation and developmental programmes (KLF4, TBX5, TFAP2A and homeobox genes) and the microRNAs miR-10a and miR-10b which target several of these deregulated genes. We show that KLF4 expression is reduced in SSc dFBs and its expression is repressed by TBX5 and TFAP2A. We also show that KLF4 is antifibrotic, and its conditional knockout in fibroblasts promotes a fibrotic phenotype.

CONCLUSIONS

Our data support a role for epigenetic dysregulation in mediating SSc susceptibility in dFBs, illustrating the intricate interplay between CpG methylation, miRNAs and transcription factors in SSc pathogenesis, and highlighting the potential for future use of epigenetic modifiers as therapies.

Smooth muscle cells in atherosclerosis: clones but not carbon copies

Our knowledge of the contribution of vascular smooth muscle cells (SMCs) to atherosclerosis has greatly advanced in the previous decade with the development of techniques allowing for the unambiguous identification and phenotypic characterization of SMC populations within the diseased vascular wall. By performing fate mapping or single-cell transcriptomics studies, or a combination of both, the field has made key observations: SMCs populate atherosclerotic lesions by the selective expansion and investment of a limited number of medial SMCs, which undergo profound and diverse modifications of their original phenotype and function. Thus, if SMCs residing within atherosclerotic lesions and contributing to the disease are clones, they are not carbon copies and can play atheroprotective or atheropromoting roles, depending on the nature of their phenotypic transitions. Tremendous progress has been made in identifying the transcriptional mechanisms biasing SMC fate. In the present review, we have summarized the recent advances in characterizing SMC investment and phenotypic diversity and the molecular mechanisms controlling SMC fate in atherosclerotic lesions. We have also discussed some of the remaining questions associated with these breakthrough observations. These questions include the underlying mechanisms regulating the phenomenon of SMC oligoclonal expansion; whether single-cell transcriptomics is reliable and sufficient to ascertain SMC functions and contributions during atherosclerosis development and progression; and how SMC clonality and phenotypic plasticity affects translational research and the therapeutic approaches developed to prevent atherosclerosis complications. Finally, we have discussed the complementary approaches the field should lean toward by combining single-cell phenotypic categorization and functional studies to understand further the complex SMC behavior and contribution in atherosclerosis.

High Cardiovascular Risk in Older Men with Poor Bone Microarchitecture-The Prospective STRAMBO Study

Data on the association between bone microarchitecture and cardiovascular disease (CVD) in men are scarce. We studied the link of bone microarchitecture and areal bone mineral density (aBMD) with the risk of major adverse coronary event (MACE) in a cohort of men aged 60 to 87 years followed prospectively for 8 years. At baseline, aBMD was measured using a Hologic Discovery-A device. Bone microarchitecture was assessed at distal radius and tibia by high-resolution peripheral quantitative computed tomography (XtremeCT Scanco device). During the study, 53 men had incident MACE. The analyses were adjusted for confounders related to bone and CVD. In 813 men (53 MACEs), higher aBMD at the lumbar spine, hip, whole body, and radius was associated with lower risk of MACE (hazard ratio [HR] = 0.44-0.71/SD, p < .025 to < .001). In 745 men having valid distal radius scan (47 MACEs), higher cortical density (Ct.BMD) and higher cortical thickness (Ct.Th^d ) were associated with lower risk of MACE. This risk was higher in men in the lowest quintile of cortical measures versus the four upper quintiles combined (Ct.BMD: HR = 2.12, 95% confidence interval [CI] 1.08-4.17, p < .025). Findings were similar in 779 men having valid distal tibia scan (48 MACEs). At both sites, higher estimated stiffness and higher failure load were associated with a lower risk of MACE. The risk of MACE was higher in men in the lowest quintile of the measures of bone strength versus four upper quintiles jointly (distal radius stiffness: HR = 2.46, 95% CI 1.27-4.74, p < .01). Similar results were obtained in 638 men without prior fragility fracture and in 689 men without ischemic heart disease at baseline. Thus, in older men followed prospectively for 8 years, higher aBMD, preserved cortical bone status, and higher estimated bone strength were associated with lower risk of MACE after adjustment for relevant confounders. © 2021 American Society for Bone and Mineral Research (ASBMR).

Abdominal aortic calcification is associated with decline in handgrip strength in the U.S. adult population ≥40 years of age

BACKGROUND AND AIMS

The present study investigated the association between abdominal aortic calcification (AAC) and handgrip strength (HGS) and the ability of HGS to predict an increased AAC phenotype in adults.

METHODS AND RESULTS

The analysis consisted of data for 3140 men and women aged ≥40 years (51.7% women) from the 2013-2014 NHANES. Lateral scans of the thoraco-lumbar spine (L1-L4) were scored for AAC using a validated 8-point scale (AAC-8); subjects with a score of ≥3 were considered at increased risk for cardiovascular disease due to a high AAC phenotype. HGS was assessed using a grip dynamometer. The prevalence of severe AAC in the population was 9.0%. Decline in HGS was associated with higher AAC-8 scores in men and women (p < 0.001). General linear model analysis showed that HGS levels were negatively associated with high AAC (p < 0.001) and AAC-8 status for both sexes. Likewise, for each 5-kg higher HGS, there lower odds of a high AAC phenotype (in men OR = 0.73, CI95%, 0.64-0.84) and (women OR = 0.58, CI95%, 0.47-0.70). Receiver operating characteristic curve analysis showed that the HGS threshold value to detect high risk of AAC in adults was ≥37.3 kg (AUC = 0.692) in men and 25.1 kg (AUC = 0.705) in women.

CONCLUSION

Lower muscular strength, as measured by HGS, is associated with higher AAC scores in the U.S. population ≥40 years of age. Accordingly, maintenance of muscular strength during aging may protect adults against vascular calcification, an independent predictor of cardiovascular events. HGS measurement seems to be a valid screening tool for detecting a high ACC phenotype in adults.

Molecular Mechanisms Underlying Remodeling of Ductus Arteriosus: Looking beyond the Prostaglandin Pathway

The ductus arteriosus (DA) is a physiologic vessel crucial for fetal circulation. As a major regulating factor, the prostaglandin pathway has long been the target for DA patency maintenance or closure. However, the adverse effect of prostaglandins and their inhibitors has been a major unsolved clinical problem. Furthermore, a significant portion of patients with patent DA fail to respond to cyclooxygenase inhibitors that target the prostaglandin pathway. These unresponsive medical patients ultimately require surgical intervention and highlight the importance of exploring pathways independent from this well-recognized prostaglandin pathway. The clinical limitations of prostaglandin-targeting therapeutics prompted us to investigate molecules beyond the prostaglandin pathway. Thus, this article introduces molecules independent from the prostaglandin pathway based on their correlating mechanisms contributing to vascular remodeling. These molecules may serve as potential targets for future DA patency clinical management.

AntagomiR-29b inhibits vascular and valvular calcification and improves heart function in rats

We aimed to investigate the role of the miR‐29b and its effect on TGF‐β3 pathway in vascular and valvular calcification in a rat model of calcific aortic valve diseases (CAVD). A rat model of CAVD was established by administration of warfarin plus vitamin K. The expression levels of miR‐29b, osteogenic markers and other genes were determined by qRT‐PCR, Western blot and/or immunofluorescence and immunohistochemistry. The calcium content and alkaline phosphatase (ALP) activity were measured. The calcium content, ALP activity and osteogenic markers levels in calcified aorta and aortic valve were augmented compared to controls. The expression of miR‐29b, p‐Smad3, and Wnt3 and β‐catenin was significantly up‐regulated, whereas TGF‐β3 was markedly down‐regulated. However, compared with the CAVD model group, the calcium content and ALP activity in rats treated with antagomiR‐29b were significantly decreased, and antagomiR‐29b administration reversed the effects of CAVD model on the expression of miR‐29b and osteogenic markers. Inhibition of miR‐29b in CAVD rats prevented from vascular and valvular calcification and induced TGF‐β3 expression, suggesting that the miR‐29b/TGF‐β3 axis may play a regulatory role in the pathogenesis of vascular and valvular calcification and could play a significant role in the treatment of CAVD and other cardiovascular diseases.

Vascular Calcification: An Important Understanding in Nephrology

Vascular calcification (VC) is a life-threatening state in chronic kidney disease (CKD). High cardiovascular mortality and morbidity of CKD cases may root from medial VC promoted by hyperphosphatemia. Vascular calcification is an active, highly regulated, and complex biological process that is mediated by genetics, epigenetics, dysregulated form of matrix mineral metabolism, hormones, and the activation of cellular signaling pathways. Moreover, gut microbiome as a source of uremic toxins (eg, phosphate, advanced glycation end products and indoxyl-sulfate) can be regarded as a potential contributor to VC in CKD. Here, an update on different cellular and molecular processes involved in VC in CKD is discussed to elucidate the probable therapeutic pathways in the future.

Comparative gene array analyses of severe elastic fiber defects in late embryonic and newborn mouse aorta

Elastic fibers provide reversible elasticity to the large arteries and are assembled during development when hemodynamic forces are increasing. Mutations in elastic fiber genes are associated with cardiovascular disease. Mice lacking expression of the elastic fiber genes elastin ( Eln-/-), fibulin-4 ( Efemp2-/-), or lysyl oxidase ( Lox-/-) die at birth with severe cardiovascular malformations. All three genetic knockout models have elastic fiber defects, aortic wall thickening, and arterial tortuosity. However, Eln-/- mice develop arterial stenoses, while Efemp2-/- and Lox-/- mice develop ascending aortic aneurysms. We performed comparative gene array analyses of these three genetic models for two vascular locations and developmental stages to determine differentially expressed genes and pathways that may explain the common and divergent phenotypes. We first examined arterial morphology and wall structure in newborn mice to confirm that the lack of elastin, fibulin-4, or lysyl oxidase expression provided the expected phenotypes. We then compared gene expression levels for each genetic model by three-way ANOVA for genotype, vascular location, and developmental stage. We found three genes upregulated by genotype in all three models, Col8a1, Igfbp2, and Thbs1, indicative of a common response to severe elastic fiber defects in developing mouse aorta. Genes that are differentially regulated by vascular location or developmental stage in all three models suggest mechanisms for location or stage-specific disease pathology. Comparison of signaling pathways enriched in all three models shows upregulation of integrins and matrix proteins involved in early wound healing, but not of mature matrix molecules such as elastic fiber proteins or fibrillar collagens.

Cortistatin inhibits arterial calcification in rats via GSK3β/β-catenin and protein kinase C signalling but not c-Jun N-terminal kinase signalling

AIM

Cortistatin (CST) is a newly discovered endogenous active peptide that exerts protective effects on the cardiovascular system. However, the relationship between CST and aortic calcification and the underlying mechanism remain obscure. Therefore, we investigated effects of CST on aortic calcification and its signalling pathways.

METHODS

Calcium content and alkaline phosphatase (ALP) activity were measured using the o-cresolphthalein colorimetric method and ALP assay kit respectively. Protein expression of smooth muscle (SM)-ɑ-actin, osteocalcin (OCN), β-catenin, glycogen synthase kinase 3β (GSK3β), p-GSK3β, protein kinase C (PKC), p-PKC, c-Jun N-terminal kinase (JNK) and p-JNK was determined using Western blotting.

RESULTS

In aorta from a rat vitamin D3 calcification model, CST abrogated calcium deposition and pathological damage, decreased the protein expression of OCN and β-catenin and increased SM-ɑ-actin expression. In a rat cultured vascular smooth muscular cell (VSMC) calcification model induced by β-glycerophosphate (β-GP), CST inhibited the increase in ALP activity, calcium content and OCN protein and the decrease in SM-α-actin expression. CST also inhibited the β-GP-induced increase in p-GSK3β and β-catenin protein (both P < .05). The inhibitory effects of CST on ALP activity, calcium deposition and β-catenin protein were abolished by pretreatment with lithium chloride, a GSK3β inhibitor. CST promoted the protein expression of p-PKC by 68.5% (P < .01), but not p-JNK. The ability of CST to attenuate β-GP-induced increase in ALP activity, calcium content and OCN expression in the VSMC model was abolished by pretreatment with the PKC inhibitor Go6976.

CONCLUSION

These results indicate that CST inhibits aortic calcification and osteogenic differentiation of VSMCs likely via the GSK3β/β-catenin and PKC signalling pathways, but not JNK signalling pathway.

Cell Phenotype Transitions in Cardiovascular Calcification

Cardiovascular calcification was originally considered a passive, degenerative process, however with the advance of cellular and molecular biology techniques it is now appreciated that ectopic calcification is an active biological process. Vascular calcification is the most common form of ectopic calcification, and aging as well as specific disease states such as atherosclerosis, diabetes, and genetic mutations, exhibit this pathology. In the vessels and valves, endothelial cells, smooth muscle cells, and fibroblast-like cells contribute to the formation of extracellular calcified nodules. Research suggests that these vascular cells undergo a phenotypic switch whereby they acquire osteoblast-like characteristics, however the mechanisms driving the early aspects of these cell transitions are not fully understood. Osteoblasts are true bone-forming cells and differentiate from their pluripotent precursor, the mesenchymal stem cell (MSC); vascular cells that acquire the ability to calcify share aspects of the transcriptional programs exhibited by MSCs differentiating into osteoblasts. What is unknown is whether a fully-differentiated vascular cell directly acquires the ability to calcify by the upregulation of osteogenic genes or, whether these vascular cells first de-differentiate into an MSC-like state before obtaining a “second hit” that induces them to re-differentiate down an osteogenic lineage. Addressing these questions will enable progress in preventative and regenerative medicine strategies to combat vascular calcification pathologies. In this review, we will summarize what is known about the phenotypic switching of vascular endothelial, smooth muscle, and valvular cells.

Glucocorticoids, genes and brain function

The identification of key genes in transcriptomic data constitutes a huge challenge. Our review of microarray reports revealed 88 genes whose transcription is consistently regulated by glucocorticoids (GCs), such as cortisol, corticosterone and dexamethasone, in the brain. Replicable transcriptomic data were combined with biochemical and physiological data to create an integrated view of the effects induced by GCs. The most frequently reported genes were Errfi1 and Ddit4. Their up-regulation was associated with the altered transcription of genes regulating growth factor and mTORC1 signaling (Gab1, Tsc22d3, Dusp1, Ndrg2, Ppp5c and Sesn1) and progression of the cell cycle (Ccnd1, Cdkn1a and Cables1). The GC-induced reprogramming of cell function involves changes in the mRNA level of genes responsible for the regulation of transcription (Klf9, Bcl6, Klf15, Tle3, Cxxc5, Litaf, Tle4, Jun, Sox4, Sox2, Sox9, Irf1, Sall2, Nfkbia and Id1) and the selective degradation of mRNA (Tob2). Other genes are involved in the regulation of metabolism (Gpd1, Aldoc and Pdk4), actin cytoskeleton (Myh2, Nedd9, Mical2, Rhou, Arl4d, Osbpl3, Arhgef3, Sdc4, Rdx, Wipf3, Chst1 and Hepacam), autophagy (Eva1a and Plekhf1), vesicular transport (Rhob, Ehd3, Vps37b and Scamp2), gap junctions (Gjb6), immune response (Tiparp, Mertk, Lyve1 and Il6r), signaling mediated by thyroid hormones (Thra and Sult1a1), calcium (Calm2), adrenaline/noradrenaline (Adcy9 and Adra1d), neuropeptide Y (Npy1r) and histamine (Hdc). GCs also affected genes involved in the synthesis of polyamines (Azin1) and taurine (Cdo1). The actions of GCs are restrained by feedback mechanisms depending on the transcription of Sgk1, Fkbp5 and Nr3c1. A side effect induced by GCs is increased production of reactive oxygen species. Available data show that the brain's response to GCs is part of an emergency mode characterized by inactivation of non-core activities, restrained inflammation, restriction of investments (growth), improved efficiency of energy production and the removal of unnecessary or malfunctioning cellular components to conserve energy and maintain nutrient supply during the stress response.

Implication of molecular vascular smooth muscle cell heterogeneity among arterial beds in arterial calcification

Vascular calcification is a strong and independent predictive factor for cardiovascular complications and mortality. Our previous work identified important discrepancies in plaque composition and calcification types between carotid and femoral arteries. The objective of this study is to further characterize and understand the heterogeneity in vascular calcification among vascular beds, and to identify molecular mechanisms underlying this process. We established ECLAGEN biocollection that encompasses human atherosclerotic lesions and healthy arteries from different locations (abdominal, thoracic aorta, carotid, femoral, and infrapopliteal arteries) for histological, cell isolation, and transcriptomic analysis. Our results show that lesion composition differs between these locations. Femoral arteries are the most calcified arteries overall. They develop denser calcifications (sheet-like, nodule), and are highly susceptible to osteoid metaplasia. These discrepancies may derive from intrinsic differences between SMCs originating from these locations, as microarray analysis showed specific transcriptomic profiles between primary SMCs isolated from each arterial bed. These molecular differences translated into functional disparities. SMC from femoral arteries showed the highest propensity to mineralize due to an increase in basal TGFβ signaling. Our results suggest that biological heterogeneity of resident vascular cells between arterial beds, reflected by our transcriptomic analysis, is critical in understanding plaque biology and calcification, and may have strong implications in vascular therapeutic approaches.

WNT Signaling in Cardiac and Vascular Disease

WNT signaling is an elaborate and complex collection of signal transduction pathways mediated by multiple signaling molecules. WNT signaling is critically important for developmental processes, including cell proliferation, differentiation and tissue patterning. Little WNT signaling activity is present in the cardiovascular system of healthy adults, but reactivation of the pathway is observed in many pathologies of heart and blood vessels. The high prevalence of these pathologies and their significant contribution to human disease burden has raised interest in WNT signaling as a potential target for therapeutic intervention. In this review, we first will focus on the constituents of the pathway and their regulation and the different signaling routes. Subsequently, the role of WNT signaling in cardiovascular development is addressed, followed by a detailed discussion of its involvement in vascular and cardiac disease. After highlighting the crosstalk between WNT, transforming growth factor-β and angiotensin II signaling, and the emerging role of WNT signaling in the regulation of stem cells, we provide an overview of drugs targeting the pathway at different levels. From the combined studies we conclude that, despite the sometimes conflicting experimental data, a general picture is emerging that excessive stimulation of WNT signaling adversely affects cardiovascular pathology. The rapidly increasing collection of drugs interfering at different levels of WNT signaling will allow the evaluation of therapeutic interventions in the pathway in relevant animal models of cardiovascular diseases and eventually in patients in the near future, translating the outcomes of the many preclinical studies into a clinically relevant context.

Genome-wide association study of coronary artery calcified atherosclerotic plaque in African Americans with type 2 diabetes

Background

Coronary artery calcified atherosclerotic plaque (CAC) predicts cardiovascular disease (CVD). Despite exposure to more severe conventional CVD risk factors, African Americans (AAs) are less likely to develop CAC, and when they do, have markedly lower levels than European Americans. Genetic factors likely contribute to the observed ethnic differences. To identify genes associated with CAC in AAs with type 2 diabetes (T2D), a genome-wide association study (GWAS) was performed using the Illumina 5 M chip in 691 African American-Diabetes Heart Study participants (AA-DHS), with replication in 205 Jackson Heart Study (JHS) participants with T2D. Genetic association tests were performed on the genotyped and 1000 Genomes-imputed markers separately for each study, and combined in a meta-analysis.

Results

Single nucleotide polymorphisms (SNPs), rs11353135 (2q22.1), rs16879003 (6p22.3), rs5014012, rs58071836 and rs10244825 (all on chromosome 7), rs10918777 (9q31.2), rs13331874 (16p13.3) and rs4459623 (18q12.1) were associated with presence and/or quantity of CAC in the AA-DHS and JHS, with meta-analysis p-values ≤8.0 × 10⁻⁷. The strongest result in AA-DHS alone was rs6491315 in the 13q32.1 region (parameter estimate (SE) = −1.14 (0.20); p-value = 9.1 × 10⁻⁹). This GWAS peak replicated a previously reported AA-DHS CAC admixture signal (rs7492028, LOD score 2.8).

Conclusions

Genetic association between SNPs on chromosomes 2, 6, 7, 9, 16 and 18 and CAC were detected in AAs with T2D from AA-DHS and replicated in the JHS. These data support a role for genetic variation on these chromosomes as contributors to CAC in AAs with T2D, as well as to variation in CAC between populations of African and European ancestry.

Electronic supplementary material

The online version of this article (10.1186/s12863-017-0572-9) contains supplementary material, which is available to authorized users.

Experimental preeclampsia in rats affects vascular gene expression patterns

Normal pregnancy requires adaptations of the maternal vasculature. During preeclampsia these adaptations are not well established, which may be related to maternal hypertension and proteinuria. The effects of preeclampsia on the maternal vasculature are not yet fully understood. We aimed to evaluate gene expression in aortas of pregnant rats with experimental preeclampsia using a genome wide microarray. Aortas were isolated from pregnant Wistar outbred rats with low-dose LPS-induced preeclampsia (ExpPE), healthy pregnant (Pr), non-pregnant and low-dose LPS-infused non-pregnant rats. Gene expression was measured by microarray and validated by real-time quantitative PCR. Gene Set Enrichment Analysis was performed to compare the groups. Functional analysis of the aorta was done by isotonic contraction measurements while stimulating aortic rings with potassium chloride. 526 genes were differentially expressed, and positive enrichment of “potassium channels”, “striated muscle contraction”, and “neuronal system” gene sets were found in ExpPE vs. Pr. The potassium chloride-induced contractile response of ExpPE aortic rings was significantly decreased compared to this response in Pr animals. Our data suggest that potassium channels, neuronal system and (striated) muscle contraction in the aorta may play a role in the pathophysiology of experimental preeclampsia. Whether these changes are also present in preeclamptic women needs further investigation.

Notch Signaling in Development, Tissue Homeostasis, and Disease

Notch signaling is an evolutionarily highly conserved signaling mechanism, but in contrast to signaling pathways such as Wnt, Sonic Hedgehog, and BMP/TGF-β, Notch signaling occurs via cell-cell communication, where transmembrane ligands on one cell activate transmembrane receptors on a juxtaposed cell. Originally discovered through mutations in Drosophila more than 100 yr ago, and with the first Notch gene cloned more than 30 yr ago, we are still gaining new insights into the broad effects of Notch signaling in organisms across the metazoan spectrum and its requirement for normal development of most organs in the body. In this review, we provide an overview of the Notch signaling mechanism at the molecular level and discuss how the pathway, which is architecturally quite simple, is able to engage in the control of cell fates in a broad variety of cell types. We discuss the current understanding of how Notch signaling can become derailed, either by direct mutations or by aberrant regulation, and the expanding spectrum of diseases and cancers that is a consequence of Notch dysregulation. Finally, we explore the emerging field of Notch in the control of tissue homeostasis, with examples from skin, liver, lung, intestine, and the vasculature.

Vascular smooth muscle LRP6 limits arteriosclerotic calcification in diabetic LDLR-/- mice by restraining noncanonical Wnt signals

RATIONALE

Wnt signaling regulates key aspects of diabetic vascular disease.

OBJECTIVE

We generated SM22-Cre;LRP6(fl/fl);LDLR(-/-) mice to determine contributions of Wnt coreceptor low-density lipoprotein receptor-related protein 6 (LRP6) in the vascular smooth muscle lineage of male low-density lipoprotein receptor-null mice, a background susceptible to diet (high-fat diet)-induced diabetic arteriosclerosis.

METHODS AND RESULTS

As compared with LRP6(fl/fl);LDLR(-/-) controls, SM22-Cre;LRP6(fl/fl);LDLR(-/-) (LRP6-VKO) siblings exhibited increased aortic calcification on high-fat diet without changes in fasting glucose, lipids, or body composition. Pulse wave velocity (index of arterial stiffness) was also increased. Vascular calcification paralleled enhanced aortic osteochondrogenic programs and circulating osteopontin (OPN), a matricellular regulator of arteriosclerosis. Survey of ligands and Frizzled (Fzd) receptor profiles in LRP6-VKO revealed upregulation of canonical and noncanonical Wnts alongside Fzd10. Fzd10 stimulated noncanonical signaling and OPN promoter activity via an upstream stimulatory factor (USF)-activated cognate inhibited by LRP6. RNA interference revealed that USF1 but not USF2 supports OPN expression in LRP6-VKO vascular smooth muscle lineage, and immunoprecipitation confirmed increased USF1 association with OPN chromatin. ML141, an antagonist of cdc42/Rac1 noncanonical signaling, inhibited USF1 activation, osteochondrogenic programs, alkaline phosphatase, and vascular smooth muscle lineage calcification. Mass spectrometry identified LRP6 binding to protein arginine methyltransferase (PRMT)-1, and nuclear asymmetrical dimethylarginine modification was increased with LRP6-VKO. RNA interference demonstrated that PRMT1 inhibits OPN and TNAP, whereas PRMT4 supports expression. USF1 complexes containing the histone H3 asymmetrically dimethylated on Arg-17 signature of PRMT4 are increased with LRP6-VKO. Jmjd6, a demethylase downregulated with LRP6 deficiency, inhibits OPN and TNAP expression, USF1: histone H3 asymmetrically dimethylated on Arg-17 complex formation, and transactivation.

CONCLUSIONS

LRP6 restrains vascular smooth muscle lineage noncanonical signals that promote osteochondrogenic differentiation, mediated in part via USF1- and arginine methylation-dependent relays.