Six Shades of Vascular Smooth Muscle Cells Illuminated by KLF4 (Krüppel-Like Factor 4)

Regional differences in three-dimensional fiber organization, smooth muscle cell phenotype, and contractility in the pregnant mouse cervix

The orientation and function of smooth muscle in the cervix may contribute to the important biomechanical properties that change during pregnancy. Thus, this study examined the three-dimensional structure, smooth muscle phenotype, and mechanical and contractile functions of the upper and lower cervix of nongravid (not pregnant) and gravid (pregnant) mice. In gravid cervix, we uncovered region-specific changes in the structure and organization of fiber tracts. We also detected a greater proportion of contractile smooth muscle cells (SMCs), but an equal proportion of synthetic SMCs, in the upper versus lower cervix. Furthermore, we revealed that the lower cervix had infrequent spontaneous contractions, distension had a minimal effect on contractility, and the upper cervix had forceful contractions in response to labor-inducing agents (oxytocin and prostaglandin E2). These findings identify regional differences in cervix contractility related to contractile SMC content and fiber organization, which could be targeted with diagnostic technologies and for therapeutic intervention.

RNA binding protein with multiple splicing (RBPMS) promotes contractile phenotype splicing in human embryonic stem cell-derived vascular smooth muscle cells

AIMS

Differentiated vascular smooth muscle cells (VSMCs) express a unique network of mRNA isoforms via smooth muscle-specific alternative pre-mRNA splicing (SM-AS) in functionally critical genes, including those comprising the contractile machinery. We previously described RNA Binding Protein with Multiple Splicing (RBPMS) as a potent driver of differentiated SM-AS in the rat PAC1 VSMC cell line. What is unknown is how RBPMS affects VSMC phenotype and behaviour. Here, we aimed to dissect the role of RBPMS in SM-AS in human cells and determine the impact on VSMC phenotypic properties.

METHODS AND RESULTS

We used human embryonic stem cell-derived VSMCs (hESC-VSMCs) as our platform. hESC-VSMCs are inherently immature, and we found that they display only partially differentiated SM-AS patterns while RBPMS protein levels are low. We found that RBPMS over-expression induces SM-AS patterns in hESC-VSMCs akin to the contractile tissue VSMC splicing patterns. We present in silico and experimental findings that support RBPMS' splicing activity as mediated through direct binding and via functional cooperativity with splicing factor RBFOX2 on a significant subset of targets. We also demonstrate that RBPMS can alter the motility and the proliferative properties of hESC-VSMCs to mimic a more differentiated state.

CONCLUSION

Overall, this study emphasizes a critical role for RBPMS in establishing the contractile phenotype splicing programme of human VSMCs.

Long Noncoding RNA Function in Smooth Muscle Cell Plasticity and Atherosclerosis

In the healthy mature artery, vascular cells, including endothelial cells, smooth muscle cells (SMCs), and fibroblasts are organized in different layers, performing specific functions. SMCs located in the media are in a differentiated state and exhibit a contractile phenotype. However, in response to vascular injury within the intima, stimuli from activated endothelial cells and recruited inflammatory cells reach SMCs and induce a series of remodeling events in them, known as phenotypic switching. Indeed, SMCs retain a certain degree of plasticity and are able to transdifferentiate into other cell types that are crucial for both the formation and development of atherosclerotic lesions. Because of their highly cell-specific expression profiles and their widely recognized contribution to physiological and disease-related biological processes, long noncoding RNAs have received increasing attention in atherosclerosis research. Dynamic fluctuations in their expression have been implicated in the regulation of SMC identity. Sophisticated technologies are now available to allow researchers to access single-cell transcriptomes and study long noncoding RNA function with unprecedented precision. Here, we discuss the state of the art of long noncoding RNAs regulation of SMC phenotypic switching, describing the methodologies used to approach this issue and evaluating the therapeutic perspectives of exploiting long noncoding RNAs as targets in atherosclerosis.

Intrinsic GATA4 expression sensitizes the aortic root to dilation in a Loeys-Dietz syndrome mouse model

Loeys-Dietz syndrome (LDS) is a connective tissue disorder caused by mutations that decrease transforming growth factor-β signaling. LDS-causing mutations increase the risk of aneurysm throughout the arterial tree, yet the aortic root is a site of heightened susceptibility. Here we investigate the heterogeneity of vascular smooth muscle cells (VSMCs) in the aorta of Tgfbr1M318R/+ LDS mice by single-cell transcriptomics to identify molecular determinants of this vulnerability. Reduced expression of components of the extracellular matrix-receptor apparatus and upregulation of stress and inflammatory pathways were observed in all LDS VSMCs. However, regardless of genotype, a subset of Gata4-expressing VSMCs predominantly located in the aortic root intrinsically displayed a less differentiated, proinflammatory profile. A similar population was also identified among aortic VSMCs in a human single-cell RNA sequencing dataset. Postnatal VSMC-specific Gata4 deletion reduced aortic root dilation in LDS mice, suggesting that this factor sensitizes the aortic root to the effects of impaired transforming growth factor-β signaling.

Perspective: Pathological transdifferentiation-a novel therapeutic target for cardiovascular diseases and chronic inflammation

Pathological transdifferentiation, where differentiated cells aberrantly transform into other cell types that exacerbate disease rather than promote healing, represents a novel and significant concept. This perspective discusses its role and potential targeting in cardiovascular diseases and chronic inflammation. Current therapies mainly focus on mitigating early inflammatory response through proinflammatory cytokines and pathways targeting, including corticosteroids, TNF-α inhibitors, IL-1β monoclonal antibodies and blockers, IL-6 blockers, and nonsteroidal anti-inflammatory drugs (NSAIDs), along with modulating innate immune memory (trained immunity). However, these approaches often fail to address long-term tissue damage and functional regeneration. For instance, fibroblasts can transdifferentiate into myofibroblasts in cardiac fibrosis, and endothelial cells may undergo endothelial to mesenchymal transition (EndMT) in vascular remodeling, resulting in fibrosis and impaired tissue function. Targeting pathological transdifferentiation represents a promising therapeutic avenue by focusing on key signaling pathways that drive these aberrant cellular phenotypic and transcriptomic transitions. This approach seeks to inhibit these pathways or modulate cellular plasticity to promote effective tissue regeneration and prevent fibrosis. Such strategies have the potential to address inflammation, cell death, and the resulting tissue damage, providing a more comprehensive and sustainable treatment solution. Future research should focus on understanding the mechanisms behind pathological transdifferentiation, identifying relevant biomarkers and master regulators, and developing novel therapies through preclinical and clinical trials. Integrating these new therapies with existing anti-inflammatory treatments could enhance efficacy and improve patient outcomes. Highlighting pathological transdifferentiation as a therapeutic target could transform treatment paradigms, leading to better management and functional recovery of cardiovascular tissues in diseases and chronic inflammation.

Elabela alleviates cuproptosis and vascular calcification in vitaminD3- overloaded mice via regulation of the PPAR-γ /FDX1 signaling

BACKGROUND

Vascular calcification is a crucial pathophysiological process associated with age-related cardiovascular diseases. Elabela, a recently identified peptide, has emerged as a significant player in the regulation of cardiovascular function and homeostasis. However, the effects and underlying mechanisms of Elabela on age-related vascular calcification remain largely unexplored.

METHODS

In-vivo vascular calcifications of C57BL/6J mice (8-week-old) and young (8-week-old) or aged (72-week-old) SD rats were injected with vitamin D3 (VitD3) or saline, respectively. Furthermore, the VitD3-overloaded mice received Elabela (1 mg/kg/d), peroxisome proliferators-activated receptor-γ (PPAR-γ) activator Rosiglitazone (5 mg/kg/d) or copper-ionophore Elesclomol (20 mg/kg/d), respectively. As for in-vitro studies, primary rat vascular smooth muscle cells (VSMCs) were isolated from aortas and cultured for explore the role and underlying mechanism of Elabela in vascular calcification.

RESULTS

There were marked increases in FDX1 and Slc31a1 levels in both aortas and VSMCs during vascular calcification, coinciding with a rise in copper levels and a decrease in Elabela levels. Alizarin red and von-Kossa staining indicated that the administration of Elabela effectively hindered the progression of vascular cuproptosis and arterial calcification in VitD3-overloaded mice and rat arterial rings models. Moreover, Elabela significantly suppressed osteogenic differentiation and calcium deposition in VSMCs and strikingly reversed high phosphate-induced augmentation of FDX1 expression, DLAT aggregation as well as intracellular copper ion levels. More importantly, Elabela exhibited remarkable abilities to prevent mitochondrial dysfunctions in primary rat VSMCs by maintaining mitochondrial membrane potential, inhibiting mitochondrial division, reducing mitochondrial ROS production and increasing ATP levels. Interestingly, Elabela mitigated cellular senescence and production of pro-inflammatory cytokines including IL-1α, IL-1β, IL-6, IL-18 and TNF-α, respectively. Furthermore, Elabela upregulated the protein levels of PPAR-γ in VitD3-overloaded mice. Administrating PPAR-γ inhibitor GW9662 or blocking the efflux of intracellular copper abolished the protective effect of Elabela on vascular calcification by enhancing levels of FDX1, Slc31a1, Runx2, and BMP2.

CONCLUSION

Elabela plays a crucial role in protecting against vascular cuproptosis and arterial calcification by activating the PPAR-γ /FDX1 signaling. Elabela supplementation and cuproptosis suppression serve as effective therapeutic approaches for managing vascular calcification and related cardiovascular disorders.

Mechanistic insights into the regression of atherosclerotic plaques

Atherosclerosis is a major contributor to cardiovascular diseases and mortality globally. The progression of atherosclerotic disease results in the expansion of plaques and the development of necrotic cores. Subsequent plaque rupture can lead to thrombosis, occluding blood vessels, and end-organ ischemia with consequential ischemic injury. Atherosclerotic plaques are formed by the accumulation of lipid particles overloaded in the subendothelial layer of blood vessels. Abnormally elevated blood lipid levels and impaired endothelial function are the initial factors leading to atherosclerosis. The atherosclerosis research has never been interrupted, and the previous view was that the pathogenesis of atherosclerosis is an irreversible and chronic process. However, recent studies have found that the progression of atherosclerosis can be halted when patients' blood lipid levels are reversed to normal or lower. A large number of studies indicates that it can inhibit the progression of atherosclerosis lesions and promote the regression of atherosclerotic plaques and necrotic cores by lowering blood lipid levels, improving the repair ability of vascular endothelial cells, promoting the reverse cholesterol transport in plaque foam cells and enhancing the ability of macrophages to phagocytize and clear the necrotic core of plaque. This article reviews the progress of research on the mechanism of atherosclerotic plaque regression. Our goal is to provide guidance for developing better therapeutic approaches to atherosclerosis by reviewing and analyzing the latest scientific findings.

KLF4's role in regulating nitric oxide production and promoting microvascular formation following ischemic stroke

This study examines KLF4's role in endothelial cells (ECs), emphasizing its effects on nitric oxide (NO) production, microvascular formation, and oxidative stress regulation following ischemic stroke. Through high-throughput sequencing, we identified eight cell subpopulations in carotid artery tissues post-stroke, with KLF4 notably elevated in ECs. KLF4 overexpression in ECs promoted NO synthesis, enhanced endothelial tube formation, mitigated oxidative stress, and improved smooth muscle cells (SMCs) function, collectively boosting blood flow in ischemic regions. These findings highlight KLF4 as pivotal in vascular regeneration and oxidative stress reduction, positioning it as a promising target for cardiovascular and cerebrovascular therapies.

HIF-1α knockdown attenuates phenotypic transformation and oxidative stress induced by high salt in human aortic vascular smooth muscle cells

Increased dietary salt intake is a well-established risk factor for hypertension and related cardiovascular diseases, involving complex vascular remodeling processes. However, the specific role of hypoxia-inducible factor-1α (HIF-1α) in vascular pathophysiology under high-salt conditions remains poorly understood. This study investigates the role of HIF-1α in high-salt-induced vascular remodeling using human aortic vascular smooth muscle cells (HA-VSMCs) cultured in vitro. HA-VSMCs were divided into three groups: high-salt with HIF-1α knockdown (shHIF-1α + HS), negative control (shcontrol), and high-salt (HS). Cell viability, migration, gene expression, and protein levels were evaluated. High-salt conditions significantly increased mRNA expression of α-smooth muscle actin (α-SMA), smooth muscle protein 22 (SM22), angiotensin II type 1 receptor (AT1R), collagen I, and collagen III (p < 0.0001). HIF-1α knockdown partially attenuated these increases, particularly for α-SMA, SM22, and AT1R (p < 0.01). At the protein level, high-salt exposure markedly elevated expression of collagen III, HIF-1α, osteopontin (OPN), and angiotensin II (Ang II) (p < 0.0001). HIF-1α knockdown significantly reduced the high-salt-induced increases in collagen III and HIF-1α protein levels (p < 0.001) but had a limited effect on OPN and Ang II upregulation. Interestingly, SM22 protein expression was significantly decreased under high-salt conditions (p < 0.0001), an effect partially reversed by HIF-1α knockdown (p < 0.0001). These findings demonstrate that high-salt conditions induce complex changes in gene and protein expression in HA-VSMCs, with HIF-1α playing a crucial role in mediating many of these alterations. The study highlights the differential effects of HIF-1α on various markers of vascular remodeling and suggests that HIF-1α may be a potential therapeutic target for mitigating salt-induced vascular pathology. Further research is warranted to elucidate the mechanisms underlying the HIF-1α-dependent and -independent effects observed in this study.

Spatial Transcriptomic Approach to Understanding Coronary Atherosclerotic Plaque Stability

BACKGROUND

Coronary atherosclerotic plaques susceptible to acute coronary syndrome have traditionally been characterized by their surrounding cellular architecture. However, with the advent of intravascular imaging, novel mechanisms of coronary thrombosis have emerged, challenging our contemporary understanding of acute coronary syndrome. These intriguing findings underscore the necessity for a precise molecular definition of plaque stability. Considering this, our study aimed to investigate the vascular microenvironment in patients with stable and unstable plaques using spatial transcriptomics.

METHODS

Autopsy-derived coronary arteries were preserved and categorized by plaque stability (n=5 patients per group). We utilized the GeoMx spatial profiling platform and Whole Transcriptome Atlas to link crucial histological morphology markers in coronary lesions with differential gene expression in specific regions of interest, thereby mapping the vascular transcriptome. This innovative approach allowed us to conduct cell morphological and spatially resolved transcriptional profiling of atherosclerotic plaques while preserving crucial intercellular signaling.

RESULTS

We observed intriguing spatial and cell-specific transcriptional patterns in stable and unstable atherosclerotic plaques, showcasing regional variations within the intima and media. These regions exhibited differential expression of proinflammatory molecules (eg, IFN-γ [interferon-γ], MHC [major histocompatibility complex] class II, proinflammatory cytokines) and prothrombotic signaling pathways. By using lineage tracing through spatial deconvolution of intimal CD68+ (cluster of differentiation 68) cells, we characterized unique, intraplaque subpopulations originating from endothelial, smooth muscle, and myeloid lineages with distinct regional locations associated with plaque instability. In addition, unique transcriptional signatures were observed in vascular smooth muscle and CD68+ cells among plaques exhibiting coronary calcification.

CONCLUSIONS

Our study illuminates distinct cell-specific and regional transcriptional alterations present in unstable plaques. Furthermore, we characterize spatially resolved, in situ evidence supporting cellular transdifferentiation and intraplaque plasticity as significant contributors to plaque instability in human coronary atherosclerosis. Our results provide a powerful resource for the identification of novel mediators of acute coronary syndrome, opening new avenues for preventative and therapeutic treatments.

Integrated transcriptomics of human blood vessels defines a spatially controlled niche for early mesenchymal progenitor cells

Human blood vessel walls show concentric layers, with the outermost tunica adventitia harboring mesenchymal progenitor cells. These progenitor cells maintain vessel homeostasis and provide a robust cell source for cell-based therapies. However, human adventitial stem cell niche has not been studied in detail. Here, using spatial and single-cell transcriptomics, we characterized the phenotype, potential, and microanatomic distribution of human perivascular progenitors. Initially, spatial transcriptomics identified heterogeneity between perivascular layers of arteries and veins and delineated the tunica adventitia into inner and outer layers. From this spatial atlas, we inferred a hierarchy of mesenchymal progenitors dictated by a more primitive cell with a high surface expression of CD201 (PROCR). When isolated from humans and mice, CD201Low expression typified a mesodermal committed subset with higher osteogenesis and less proliferation than CD201High cells, with a downstream effect on canonical Wnt signaling through DACT2. CD201Low cells also displayed high translational potential for bone tissue generation.

Rapid cyclic stretching induces a synthetic, proinflammatory phenotype in cultured human intestinal smooth muscle, with the potential to alter signaling to adjacent bowel cells

Background and Aims

Bowel smooth muscle experiences mechanical stress constantly during normal function, and pathologic mechanical stressors in disease states. We tested the hypothesis that pathologic mechanical stress could alter transcription to induce smooth muscle phenotypic class switching.

Methods

Primary human intestinal smooth muscle cells (HISMCs), seeded on electrospun aligned poly-ε-caprolactone nano-fibrous scaffolds, were subjected to pathologic, high frequency (1 Hz) uniaxial 3% cyclic stretch (loaded) or kept unloaded in culture for 6 hours. Total RNA sequencing, qRT-PCR, and quantitative immunohistochemistry defined loading-induced changes in gene expression. NicheNet predicted how differentially expressed genes might impact HISMCs and other bowel cells.

Results

Loading induced differential expression of 4537 genes in HISMCs. Loaded HISMCs had a less contractile phenotype, with increased expression of synthetic SMC genes, proinflammatory cytokines, and altered expression of axon guidance molecules, growth factors and morphogens. Many differentially expressed genes encode secreted ligands that could act cell-autonomously on smooth muscle and on other cells in the bowel wall.

Discussion

HISMCs demonstrate remarkably rapid phenotypic plasticity in response to mechanical stress that may convert contractile HISMCs into proliferative, fibroblast-like cells or proinflammatory cells. These mechanical stress-induced changes in HISMC gene expression may be relevant for human bowel disease.

Spatial multiomics atlas reveals smooth muscle phenotypic transformation and metabolic reprogramming in diabetic macroangiopathy

BACKGROUND

Diabetic macroangiopathy has been the main cause of death and disability in diabetic patients. The mechanisms underlying smooth muscle cell transformation and metabolic reprogramming other than abnormal glucose and lipid metabolism remain to be further explored.

METHOD

Single-cell transcriptome, spatial transcriptome and spatial metabolome sequencing were performed on anterior tibial artery from 11 diabetic patients with amputation. Multi-omics integration, cell communication analysis, time series analysis, network analysis, enrichment analysis, and gene expression analysis were performed to elucidate the potential molecular features.

RESULT

We constructed a spatial multiomics map of diabetic blood vessels based on multiomics integration, indicating single-cell and spatial landscape of transcriptome and spatial landscape of metabolome. At the same time, the characteristics of cell composition and biological function of calcified regions were obtained by integrating spatial omics and single cell omics. On this basis, our study provides favorable evidence for the cellular fate of smooth muscle cells, which can be transformed into pro-inflammatory chemotactic smooth muscle cells, macrophage-like smooth muscle cells/foam-like smooth muscle cells, and fibroblast/chondroblast smooth muscle cells in the anterior tibial artery of diabetic patients. The smooth muscle cell phenotypic transformation is driven by transcription factors net including KDM5B, DDIT3, etc. In addition, in order to focus on metabolic reprogramming apart from abnormal glucose and lipid metabolism, we constructed a metabolic network of diabetic vascular activation, and found that HNMT and CYP27A1 participate in diabetic vascular metabolic reprogramming by combining public data.

CONCLUSION

This study constructs the spatial gene-metabolism map of the whole anterior tibial artery for the first time and reveals the characteristics of vascular calcification, the phenotypic transformation trend of SMCs, and the transcriptional driving network of SMCs phenotypic transformation of diabetic macrovascular disease. In the perspective of combining the transcriptome and metabolome, the study demonstrates the activated metabolic pathways in diabetic blood vessels and the key genes involved in diabetic metabolic reprogramming.

Breaking new ground: Unraveling the USP1/ID3/E12/P21 axis in vascular calcification

Vascular calcification (VC) poses significant challenges in cardiovascular health. This study employs single-cell transcriptome sequencing to dissect cellular dynamics in this process. We identify distinct cell subgroups, notably in vascular smooth muscle cells (VSMCs), and observe differences between calcified atherosclerotic cores and adjacent regions. Further exploration reveals ID3 as a key gene regulating VSMC function. In vitro experiments demonstrate ID3's interaction with USP1 and E12, modulating cell proliferation and osteogenic differentiation. Animal models confirm the critical role of the USP1/ID3/E12/P21 axis in VC. This study sheds light on a novel regulatory mechanism, offering potential therapeutic targets.

Metformin Improves the Function of Abdominal Aortic Aneurysm Patient-Derived Aortic Smooth Muscle Cells

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a cardiovascular risk factor. Paradoxically, a decreased risk of abdominal aortic aneurysm (AAA) presence and growth rate is described among patients with T2DM, associated with metformin use. This study aimed to investigate the effect of metformin on AAA patient-derived aortic smooth muscle cell (SMC) function.

METHODS

Aortic biopsies were obtained from patients with AAA (n = 21) and controls (n = 17) during surgery. The SMCs of non-pathological aortic controls, non-diabetic patients with AAA, and diabetic patients with AAA were cultured from explants and treated with or without metformin. The SMC contractility was measured upon ionomycin stimulation, as well as metabolic activity, proliferation, and migration. mRNA and protein expression of markers for contraction, metabolic activity, proliferation, and inflammation were measured.

RESULTS

mRNA expression of KLF4 and GYS1, genes involved in metabolic activity, differed between SMCs from non-diabetic and diabetic patients with AAA before metformin stimulation (p < .041). However, the effect of metformin on the various SMC functions was similar between non-diabetic and diabetic patients with AAA. Upon stimulation, metformin increased the contractility of AAA patient SMCs (p = .001). mRNA expression of smoothelin, a marker for the contractile phenotype, increased in SMCs of patients with AAA after treatment with metformin (p = .006). An increase in metabolic activity (p < .001) and a decrease in proliferation (p < .001) and migration were found in the SMCs of controls and patients with AAA with metformin. Increased mRNA expression of PPARγ, a nuclear receptor involved in mitochondrial biogenesis (p < .009), and a decrease in gene expression of Ki-67, a marker for proliferation (p < .005), were observed. Gene expression of inflammation markers MCP-1 and IL-6, and protein expression of NF-κB p65 decreased after treatment with metformin in patients with AAA.

CONCLUSION

This study found that metformin increases contractility and metabolic activity, and reduces proliferation, migration, and inflammation in aortic SMCs in vitro.

The vasoprotective role of IGF-1 signaling in the cerebral microcirculation: prevention of cerebral microhemorrhages in aging

Aging is closely associated with various cerebrovascular pathologies that significantly impact brain function, with cerebral small vessel disease (CSVD) being a major contributor to cognitive decline in the elderly. Consequences of CSVD include cerebral microhemorrhages (CMH), which are small intracerebral bleeds resulting from the rupture of microvessels. CMHs are prevalent in aging populations, affecting approximately 50% of individuals over 80, and are linked to increased risks of vascular cognitive impairment and dementia (VCID). Hypertension is a primary risk factor for CMHs. Vascular smooth muscle cells (VSMCs) adapt to hypertension by undergoing hypertrophy and producing extracellular matrix (ECM) components, which reinforce vessel walls. Myogenic autoregulation, which involves pressure-induced constriction, helps prevent excessive pressure from damaging the vulnerable microvasculature. However, aging impairs these adaptive mechanisms, weakening vessel walls and increasing susceptibility to damage. Insulin-like Growth Factor 1 (IGF-1) is crucial for vascular health, promoting VSMC hypertrophy, ECM production, and maintaining normal myogenic protection. IGF-1 also prevents microvascular senescence, reduces reactive oxygen species (ROS) production, and regulates matrix metalloproteinase (MMP) activity, which is vital for ECM remodeling and stabilization. IGF-1 deficiency, common in aging, compromises these protective mechanisms, increasing the risk of CMHs. This review explores the vasoprotective role of IGF-1 signaling in the cerebral microcirculation and its implications for preventing hypertension-induced CMHs in aging. Understanding and addressing the decline in IGF-1 signaling with age are crucial for maintaining cerebrovascular health and preventing hypertension-related vascular injuries in the aging population.

Tudor-SN exacerbates pathological vascular remodeling by promoting the polyubiquitination of PTEN via NEDD4-1

BACKGROUND

Dysregulation of vascular homeostasis can induce cardiovascular diseases and increase global mortality rates. Although lineage tracing studies have confirmed the pivotal role of modulated vascular smooth muscle cells (VSMCs) in the progression of pathological vascular remodeling, the underlying mechanisms are still unclear.

METHODS

The expression of Tudor-SN was determined in VSMCs of artery stenosis, PDGF-BB-treated VSMCs and atherosclerotic plaque. Loss- and gain-of-function approaches were used to explore the role of Tudor-SN in the modulation of VSMCs phenotype both in vivo and in vitro.

RESULTS

In this study, we demonstrate that Tudor-SN expression is significantly elevated in injury-induced arteries, atherosclerotic plaques, and PDGF-BB-stimulated VSMCs. Tudor-SN deficiency attenuates, but overexpression aggravates the synthetic phenotypic switching of VSMCs and pathological vascular remodeling. Loss of Tudor-SN also reduces atherosclerotic plaque formation and increases plaque stability. Mechanistically, PTEN, the major regulator of the MAPK and PI3K-AKT signaling pathways, plays a vital role in Tudor-SN-mediated regulation on proliferation and migration of VSMCs. Tudor-SN facilitates the polyubiquitination and degradation of PTEN via NEDD4-1, thus exacerbating vascular remodeling under pathological conditions. BpV (HOpic), a specific inhibitor of PTEN, not only counteracts the protective effect of Tudor-SN deficiency on proliferation and migration of VSMCs, but also abrogates the negative effect of carotid artery injury-induced vascular remodeling in mice.

CONCLUSIONS

Our findings reveal that Tudor-SN deficiency significantly ameliorated pathological vascular remodeling by reducing NEDD4-1-dependent PTEN polyubiquitination, suggesting that Tudor-SN may be a novel target for preventing vascular diseases.

Hormonal influence: unraveling the impact of sex hormones on vascular smooth muscle cells

Sex hormones play a pivotal role as endocrine hormones that exert profound effects on the biological characteristics and vascular function of vascular smooth muscle cells (VSMCs). By modulating intracellular signaling pathways, activating nuclear receptors, and regulating gene expression, sex hormones intricately influence the morphology, function, and physiological state of VSMCs, thereby impacting the biological properties of vascular contraction, relaxation, and growth. Increasing evidence suggests that abnormal phenotypic changes in VSMCs contribute to the initiation of vascular diseases, including atherosclerosis. Therefore, understanding the factors governing phenotypic alterations in VSMCs and elucidating the underlying mechanisms can provide crucial insights for refining interventions targeted at vascular diseases. Additionally, the varying levels of different types of sex hormones in the human body, influenced by sex and age, may also affect the phenotypic conversion of VSMCs. This review aims to explore the influence of sex hormones on the phenotypic switching of VSMCs and the development of associated vascular diseases in the human body.

Extracellular Vesicles as Mediators in Atherosclerotic Cardiovascular Disease

Atherosclerosis is a chronic inflammatory disease of the arterial intima, characterized by accumulation of lipoproteins and accompanying inflammation, leading to the formation of plaques that eventually trigger occlusive thrombotic events, such as myocardial infarction and ischemic stroke. Although many aspects of plaque development have been elucidated, the role of extracellular vesicles (EVs), which are lipid bilayer-delimited vesicles released by cells as mediators of intercellular communication, has only recently come into focus of atherosclerosis research. EVs comprise several subtypes that may be differentiated by their size, mode of biogenesis, or surface marker expression and cargo. The functional effects of EVs in atherosclerosis depend on their cellular origin and the specific pathophysiological context. EVs have been suggested to play a role in all stages of plaque formation. In this review, we highlight the known mechanisms by which EVs modulate atherogenesis and outline current limitations and challenges in the field.

Vascular disease persistence in giant cell arteritis: are stromal cells neglected?

Giant cell arteritis (GCA), the most common systemic vasculitis, is characterised by aberrant interactions between infiltrating and resident cells of the vessel wall. Ageing and breach of tolerance are prerequisites for GCA development, resulting in dendritic and T-cell dysfunction. Inflammatory cytokines polarise T-cells, activate resident macrophages and synergistically enhance vascular inflammation, providing a loop of autoreactivity. These events originate in the adventitia, commonly regarded as the biological epicentre of the vessel wall, with additional recruitment of cells that infiltrate and migrate towards the intima. Thus, GCA-vessels exhibit infiltrates across the vascular layers, with various cytokines and growth factors amplifying the pathogenic process. These events activate ineffective repair mechanisms, where dysfunctional vascular smooth muscle cells and fibroblasts phenotypically shift along their lineage and colonise the intima. While high-dose glucocorticoids broadly suppress these inflammatory events, they cause well known deleterious effects. Despite the emerging targeted therapeutics, disease relapse remains common, affecting >50% of patients. This may reflect a discrepancy between systemic and local mediators of inflammation. Indeed, temporal arteries and aortas of GCA-patients can show immune-mediated abnormalities, despite the treatment induced clinical remission. The mechanisms of persistence of vascular disease in GCA remain elusive. Studies in other chronic inflammatory diseases point to the fibroblasts (and their lineage cells including myofibroblasts) as possible orchestrators or even effectors of disease chronicity through interactions with immune cells. Here, we critically review the contribution of immune and stromal cells to GCA pathogenesis and analyse the molecular mechanisms by which these would underpin the persistence of vascular disease.

Epsins oversee smooth muscle cell reprograming by influencing master regulators KLF4 and OCT4

Smooth muscle cells in major arteries play a crucial role in regulating coronary artery disease. Conversion of smooth muscle cells into other adverse cell types in the artery propels the pathogenesis of the disease. Curtailing artery plaque buildup by modulating smooth muscle cell reprograming presents us a new opportunity to thwart coronary artery disease. Here, our report how Epsins, a family of endocytic adaptor proteins oversee the smooth muscle cell reprograming by influencing master regulators OCT4 and KLF4. Using single-cell RNA sequencing, we characterized the phenotype of modulated smooth muscle cells in mouse atherosclerotic plaque and found that smooth muscle cells lacking epsins undergo profound reprogramming into not only beneficial myofibroblasts but also endothelial cells for injury repair of diseased endothelium. Our work lays concrete groundwork to explore an uncharted territory as we show that depleting Epsins bolsters smooth muscle cells reprograming to endothelial cells by augmenting OCT4 activity but restrain them from reprograming to harmful foam cells by destabilizing KLF4, a master regulator of adverse reprograming of smooth muscle cells. Moreover, the expression of Epsins in smooth muscle cells positively correlates with the severity of both human and mouse coronary artery disease. Integrating our scRNA-seq data with human Genome-Wide Association Studies (GWAS) identifies pivotal roles Epsins play in smooth muscle cells in the pathological process leading to coronary artery disease. Our findings reveal a previously unexplored direction for smooth muscle cell phenotypic modulation in the development and progression of coronary artery disease and unveil Epsins and their downstream new targets as promising novel therapeutic targets for mitigating metabolic disorders.

Genetic variants and mRNA expression of KLF4 and KLF5 with hypertension: A combination of case-control study and cohort study

Hypertension (HT) is a major risk factor for cardiovascular diseases. Krüppel-like factors (KLFs) are important transcription factors in eukaryotes. Studies have reported that KLF4 and KLF5 are correlated with several cardiovascular diseases, whereas population studies for associations between HT and KLF4 or KLF5 have been rarely reported. Thus, the current study aimed to examines the association of genetic variants and mRNA expression levels of KLF4 and KLF5 with HT, as well as the effect of antihypertensive drugs on the expression levels. The associations of one single-nucleotide polymorphism (SNP) in KLF4 and three SNPs in KLF5 with HT were investigated using a combination of case-control and cohort studies. The study population were selected from a community-based population cohort in four different regions of Jiangsu Province. Risks of HT were estimated through logistic and Cox regression analyses, respectively. In addition, mRNA expression levels of KLF4 and KLF5 were measured in 246 controls and 385 HT cases selected from the cohort study as mentioned above. Among the HT cases, 263 were not taking antihypertensive drugs [AHD(-)] and 122 were taking antihypertensive drugs [AHD(+)]. In the case-control study, SNP rs9573096 (C>T) in KLF5 was significantly associated with an increased risk of HT in the additive model (adjusted odds ratio [OR], 1.106; 95% confidence interval [CI], 1.009 to 1.212). In the cohort study of the normotensive population, rs9573096 in KLF5 was also significantly associated with an increased risk of HT in the additive model (adjusted hazards ratio [HR], 1.199; 95% CI, 1.070 to 1.344). KLF4 and KLF5 mRNA expression levels were significantly higher in the AHD(-) group than in the control group ( P < 0.05), but lower in the AHD(+) group than in the AHD(-) group ( P < 0.05). The current study demonstrated the associations of KLF4 and KLF5 genetic variants with hypertension, and the indicative discriminations of mRNA expression levels of KLF4 and KLF5 for risk of hypertension and antihypertensive treatment.

L-Wnk1 Deletion in Smooth Muscle Cells Causes Aortitis and Inflammatory Shift

BACKGROUND

The long isoform of the Wnk1 (with-no-lysine [K] kinase 1) is a ubiquitous serine/threonine kinase, but its role in vascular smooth muscle cells (VSMCs) pathophysiology remains unknown.

METHODS

AngII (angiotensin II) was infused in Apoe-/- to induce experimental aortic aneurysm. Mice carrying an Sm22-Cre allele were cross-bred with mice carrying a floxed Wnk1 allele to specifically investigate the functional role of Wnk1 in VSMCs.

RESULTS

Single-cell RNA-sequencing of the aneurysmal abdominal aorta from AngII-infused Apoe-/- mice revealed that VSMCs that did not express Wnk1 showed lower expression of contractile phenotype markers and increased inflammatory activity. Interestingly, WNK1 gene expression in VSMCs was decreased in human abdominal aortic aneurysm. Wnk1-deficient VSMCs lost their contractile function and exhibited a proinflammatory phenotype, characterized by the production of matrix metalloproteases, as well as cytokines and chemokines, which contributed to local accumulation of inflammatory macrophages, Ly6Chi monocytes, and γδ T cells. Sm22Cre+Wnk1lox/lox mice spontaneously developed aortitis in the infrarenal abdominal aorta, which extended to the thoracic area over time without any negative effect on long-term survival. AngII infusion in Sm22Cre+Wnk1lox/lox mice aggravated the aortic disease, with the formation of lethal abdominal aortic aneurysms. Pharmacological blockade of γδ T-cell recruitment using neutralizing anti-CXCL9 (anti-CXC motif chemokine ligand 9) antibody treatment, or of monocyte/macrophage using Ki20227, a selective inhibitor of CSF1 receptor, attenuated aortitis. Wnk1 deletion in VSMCs led to aortic wall remodeling with destruction of elastin layers, increased collagen content, and enhanced local TGF-β (transforming growth factor-beta) 1 expression. Finally, in vivo TGF-β blockade using neutralizing anti-TGF-β antibody promoted saccular aneurysm formation and aorta rupture in Sm22 Cre+ Wnk1lox/lox mice but not in control animals.

CONCLUSION

Wnk1 is a key regulator of VSMC function. Wnk1 deletion promotes VSMC phenotype switch toward a pathogenic proinflammatory phenotype, orchestrating deleterious vascular remodeling and spontaneous severe aortitis in mice.

Loss of Smooth Muscle Tenascin-X Inhibits Vascular Remodeling Through Increased TGF-β Signaling

BACKGROUND

Vascular smooth muscle cells (VSMCs) are highly plastic. Vessel injury induces a phenotypic transformation from differentiated to dedifferentiated VSMCs, which involves reduced expression of contractile proteins and increased production of extracellular matrix and inflammatory cytokines. This transition plays an important role in several cardiovascular diseases such as atherosclerosis, hypertension, and aortic aneurysm. TGF-β (transforming growth factor-β) is critical for VSMC differentiation and to counterbalance the effect of dedifferentiating factors. However, the mechanisms controlling TGF-β activity and VSMC phenotypic regulation under in vivo conditions are poorly understood. The extracellular matrix protein TN-X (tenascin-X) has recently been shown to bind TGF-β and to prevent it from activating its receptor.

METHODS

We studied the role of TN-X in VSMCs in various murine disease models using tamoxifen-inducible SMC-specific knockout and adeno-associated virus-mediated knockdown.

RESULTS

In hypertensive and high-fat diet-fed mice, after carotid artery ligation as well as in human aneurysmal aortae, expression of Tnxb, the gene encoding TN-X, was increased in VSMCs. Mice with smooth muscle cell-specific loss of TN-X (SMC-Tnxb-KO) showed increased TGF-β signaling in VSMCs, as well as upregulated expression of VSMC differentiation marker genes during vascular remodeling compared with controls. SMC-specific TN-X deficiency decreased neointima formation after carotid artery ligation and reduced vessel wall thickening during Ang II (angiotensin II)-induced hypertension. SMC-Tnxb-KO mice lacking ApoE showed reduced atherosclerosis and Ang II-induced aneurysm formation under high-fat diet. Adeno-associated virus-mediated SMC-specific expression of short hairpin RNA against Tnxb showed similar beneficial effects. Treatment with an anti-TGF-β antibody or additional SMC-specific loss of the TGF-β receptor reverted the effects of SMC-specific TN-X deficiency.

CONCLUSIONS

In summary, TN-X critically regulates VSMC plasticity during vascular injury by inhibiting TGF-β signaling. Our data indicate that inhibition of vascular smooth muscle TN-X may represent a strategy to prevent and treat pathological vascular remodeling.

Induction of let-7d-5p miRNA modulates aortic smooth muscle inflammatory signaling and phenotypic switching

BACKGROUND AND AIMS

Activation of vascular smooth muscle cell inflammation is recognised as an important early driver of vascular disease. We have previously identified the let-7 miRNA family as important regulators of inflammation in in vitro and in vivo models of atherosclerosis. Here we investigated a dual statin/let-7d-5p miRNA combination therapy approach to target human aortic SMC (HAoSMC) activation and inflammation.

METHODS

In vitro studies using primary HAoSMCs were performed to investigate the effects of let-7d-5p miRNA overexpression and inhibition. HAoSMCs were treated with combinations of the inflammatory cytokine tumor necrosis factor-α (TNF-α), and atorvastatin or lovastatin. HAoSMC Bulk RNA-seq transcriptomics of HAoSMCs revealed downstream regulatory networks modulated by let-7d-5p miRNA overexpression and statins. Proteome profiler cytokine array, Western blotting and quantitative PCR analyses were performed on HAoSMCs to validate key findings.

RESULTS

Let-7d-5p overexpression significantly attenuated TNF-α-induced upregulation of IL-6, ICAM1, VCAM1, CCL2, CD68, MYOCD gene expression in HAoSMCs (p<0.05). Statins (atorvastatin, lovastatin) significantly attenuated inflammatory gene expression and upregulated Let-7d levels in HAoSMCs (p<0.05). Bulk RNA-seq analysis of a dual Let-7d-5p overexpression/statin therapy in HAoSMCs revealed that let-7d-5p activation and statins converge on key inflammatory pathways (IL-6, IL-1β, TNF-α, IFN-γ). Let-7d-5p overexpression led to reduced expression of the ox-LDL receptor OLR1, and this was associated with lower ox-LDL uptake in HAoSMCs. In silico analysis of smooth muscle cell phenotypic switching shows that overexpression of let-7d-5p in HAoSMCs maintains a contractile phenotype.

CONCLUSIONS

Targeting the Let-7 network alongside statins can modulate HAoSMC activation and attenuate key inflammatory pathway signals.

Kanglexin counters vascular smooth muscle cell dedifferentiation and associated arteriosclerosis through inhibiting PDGFR

BACKGROUND

Dysregulation of vascular smooth muscle cell (VSMC) function leads to a variety of diseases such as atherosclerosis and hyperplasia after injury. However, antiproliferative drug targeting VSMC exhibits poor specificity. Therefore, there is an urgent to develop highly specific antiproliferative drugs to prevention and treatment VSMC dedifferentiation associated arteriosclerosis. Kanglexin (KLX), a new anthraquinone compound designed by our team, has potential to regulate VSMC phenotype according to the physicochemical properties.

PURPOSE

This project aims to evaluate the therapeutic role of KLX in VSMC dedifferentiation and atherosclerosis, neointimal formation and illustrates the underlying molecular mechanism.

METHODS

In vivo, the ApoE-/- mice were fed with high-fat diet (HFD) for a duration of 13 weeks to establish the atherosclerotic model. And rat carotid artery injury model was performed to establish the neointimal formation model. In vitro, PDGF-BB was used to induce VSMC dedifferentiation.

RESULTS

We found that KLX ameliorated the atherosclerotic progression including atherosclerotic lesion formation, lipid deposition and collagen deposition in aorta and aortic sinus in atherosclerotic mouse model. In addition, The administration of KLX effectively ameliorated neointimal formation in the carotid artery following balloon injury in SD rats. The findings derived from molecular docking and surface plasmon resonance (SPR) experiments unequivocally demonstrate that KLX had potential to bind PDGFR-β. Mechanism research work proved that KLX prevented VSMC proliferation, migration and dedifferentiation via activating the PDGFR-β-MEK -ERK-ELK-1/KLF4 signaling pathway.

CONCLUSION

Collectively, we demonstrated that KLX effectively attenuated the progression of atherosclerosis in ApoE-/- mice and carotid arterial neointimal formation in SD rats by inhibiting VSMC phenotypic conversion via PDGFR-β-MEK-ERK-ELK-1/KLF4 signaling. KLX exhibits promising potential as a viable therapeutic agent for the treatment of VSMC phenotype conversion associated arteriosclerosis.

Mitochondria-Targeted Natural Antioxidant Nanosystem for Diabetic Vascular Calcification Therapy

The development of nanotherapy targeting mitochondria to alleviate oxidative stress is a critical therapeutic strategy for vascular calcification (VC) in diabetes. In this study, we engineered mitochondria-targeted nanodrugs (T4O@TPP/PEG-PLGA) utilizing terpinen-4-ol (T4O) as a natural antioxidant and mitochondrial protector, PEG-PLGA as the nanocarrier, and triphenylphosphine (TPP) as the mitochondrial targeting ligand. In vitro assessments demonstrated enhanced cellular uptake of T4O@TPP/PEG-PLGA, with effective mitochondrial targeting. This nanodrug successfully reduced oxidative stress induced by high glucose levels in vascular smooth muscle cells. In vivo studies showed prolonged retention of the nanomaterials in the thoracic aorta for up to 24 h. Importantly, experiments in diabetic VC models underscored the potent antioxidant properties of T4O@TPP/PEG-PLGA, as evidenced by its ability to mitigate VC and restore mitochondrial morphology. These results suggest that these nanodrugs could be a promising strategy for managing diabetic VC.

Use of iPSC-Derived Smooth Muscle Cells to Model Physiology and Pathology

The implementation of human induced pluripotent stem cell (hiPSC) models has introduced an additional tool for identifying molecular mechanisms of disease that complement animal models. Patient-derived or CRISPR/Cas9-edited induced pluripotent stem cells differentiated into smooth muscle cells (SMCs) have been leveraged to discover novel mechanisms, screen potential therapeutic strategies, and model in vivo development. The field has evolved over almost 15 years of research using hiPSC-SMCs and has made significant strides toward overcoming initial challenges such as the lineage specificity of SMC phenotypes. However, challenges both specific (eg, the lack of specific markers to thoroughly validate hiPSC-SMCs) and general (eg, a lack of transparency and consensus around methodology in the field) remain. In this review, we highlight the recent successes and remaining challenges of the hiPSC-SMC model.

Parathyroid hormone-PTH1R signaling in cardiovascular disease and homeostasis

Primary hyperparathyroidism (pHPT) afflicts our aging population with an incidence approaching 50 per 100 000 patient-years at a female:male ratio of ~3:1. Decisions surrounding surgical management are currently driven by age, hypercalcemia severity, presence of osteoporosis, renal insufficiency, or hypercalciuria with or without nephrolithiasis. Cardiovascular (CV) disease (CVD) is not systematically considered. This is notable since the parathyroid hormone (PTH) 1 receptor (PTH1R) is biologically active in the vasculature, and adjusted CV mortality risk is increased almost threefold in individuals with pHPT who do not meet contemporary recommendations for surgical cure. We provide an overview of epidemiology, pharmacology, and physiology that highlights the need to: (i) identify biomarkers that establish a healthy 'set point' for CV PTH1R signaling tone; (ii) better understand the pharmacokinetic-pharmacodynamic (PK-PD) relationships of PTH1R ligands in CV homeostasis; and (iii) incorporate CVD risk assessment into the management of hyperparathyroidism.

Unravelling the molecular interplay: SUMOylation, PML nuclear bodies and vascular cell activity in health and disease

In the seemingly well-researched field of vascular research, there are still many underestimated factors and molecular mechanisms. In recent years, SUMOylation has become increasingly important. SUMOylation is a post-translational modification in which small ubiquitin-related modifiers (SUMO) are covalently attached to target proteins. Sites where these SUMO modification processes take place in the cell nucleus are PML nuclear bodies (PML-NBs) - multiprotein complexes with their essential main component and organizer, the PML protein. PML and SUMO, either alone or as partners, influence a variety of cellular processes, including regulation of transcription, senescence, DNA damage response and defence against microorganisms, and are involved in innate immunity and inflammatory responses. They also play an important role in maintaining homeostasis in the vascular system and in pathological processes leading to the development and progression of cardiovascular diseases. This review summarizes information about the function of SUMO(ylation) and PML(-NBs) in the human vasculature from angiogenesis to disease and highlights their clinical potential as drug targets.

Dimethyl Fumarate Mediates Sustained Vascular Smooth Muscle Cell Remodeling in a Mouse Model of Cerebral Aneurysm

Cerebral aneurysms (CA) are a type of vascular disease that causes significant morbidity and mortality with rupture. Dysfunction of the vascular smooth muscle cells (VSMCs) from circle of Willis (CoW) vessels mediates CA formation, as they are the major cell type of the arterial wall and play a role in maintaining vessel integrity. Dimethyl fumarate (DMF), a first-line oral treatment for relapsing-remitting multiple sclerosis, has been shown to inhibit VSMC proliferation and reduce CA formation in a mouse model. Potential unwanted side effects of DMF on VSMC function have not been investigated yet. The present study characterizes the impact of DMF on VSMC using single-cell RNA-sequencing (scRNA-seq) in CoW vessels following CA induction and further explores its role in mitochondrial function using in vitro VSMC cultures. Two weeks of DMF treatment following CA induction impaired the transcription of the glutathione redox system and downregulated mitochondrial respiration genes in VSMCs. In vitro, DMF treatment increased lactate formation and enhanced the mitochondrial production of reactive oxygen species (ROS). These effects rendered VSMCs vulnerable to oxidative stress and led to mitochondrial dysfunction and enhancement of apoptosis. Taken together, our data support the concept that the DMF-mediated antiproliferative effect on VSMCs is linked to disturbed antioxidative functions resulting in altered mitochondrial metabolism. This negative impact of DMF treatment on VSMCs may be linked to preexisting alterations of cerebrovascular function due to renal hypertension. Therefore, before severe adverse effects emerge, it would be clinically relevant to develop indices or biomarkers linked to this disturbed antioxidative function to monitor patients undergoing DMF treatment.

Graphene Far-Infrared Irradiation Can Effectively Relieve the Blood Pressure Level of Rat Untr-HT in Primary Hypertension

Graphene, when electrified, generates far-infrared radiation within the wavelength range of 4 μm to 14 μm. This range closely aligns with the far-infrared band (3 μm to 15 μm), which produces unique physiological effects. Contraction and relaxation of vascular smooth muscle play a significant role in primary hypertension, involving the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate pathway and the renin-angiotensin-aldosterone system. This study utilized spontaneously hypertensive rats (SHRs) as an untr-HT to investigate the impact of far-infrared radiation at specific wavelengths generated by electrified graphene on vascular smooth muscle and blood pressure. After 7 weeks, the blood pressure of the untr-HT group rats decreased significantly with a notable reduction in the number of vascular wall cells and the thickness of the vascular wall, as well as a decreased ratio of vessel wall thickness to lumen diameter. Additionally, blood flow perfusion significantly increased, and the expression of F-actin in vascular smooth muscle myosin decreased significantly. Serum levels of angiotensin II (Ang-II) and endothelin 1 (ET-1) were significantly reduced, while nitric oxide synthase (eNOS) expression increased significantly. At the protein level, eNOS expression decreased significantly, while α-SMA expression increased significantly in aortic tissue. At the gene level, expressions of eNOS and α-SMA in aortic tissue significantly increased. Furthermore, the content of nitric oxide (NO) in the SHR's aortic tissue increased significantly. These findings confirm that graphene far-infrared radiation enhances microcirculation, regulates cytokines affecting vascular smooth muscle contraction, and modifies vascular morphology and smooth muscle phenotype, offering relief for primary hypertension.

The Multifaceted Nature of Macrophages in Cardiovascular Disease

As the leading cause of mortality worldwide, cardiovascular disease (CVD) represents a variety of heart diseases and vascular disorders, including atherosclerosis, aneurysm, ischemic injury in the heart and brain, arrythmias, and heart failure. Macrophages, a diverse population of immune cells that can promote or suppress inflammation, have been increasingly recognized as a key regulator in various processes in both healthy and disease states. In healthy conditions, these cells promote the proper clearance of cellular debris, dead and dying cells, and provide a strong innate immune barrier to foreign pathogens. However, macrophages can play a detrimental role in the progression of disease as well, particularly those inflammatory in nature. This review will focus on the current knowledge regarding the role of macrophages in cardiovascular diseases.

N6-methyladenosine-driven miR-143/145-KLF4 circuit orchestrates the phenotypic switch of pulmonary artery smooth muscle cells

Pulmonary hypertension (PH) is characterized by vascular remodeling predominantly driven by a phenotypic switching in pulmonary artery smooth muscle cells (PASMCs). However, the underlying mechanisms for this phenotypic alteration remain incompletely understood. Here, we identified that RNA methyltransferase METTL3 is significantly elevated in the lungs of hypoxic PH (HPH) mice and rats, as well as in the pulmonary arteries (PAs) of HPH rats. Targeted deletion of Mettl3 in smooth muscle cells exacerbated hemodynamic consequences of hypoxia-induced PH and accelerated pulmonary vascular remodeling in vivo. Additionally, the absence of METTL3 markedly induced phenotypic switching in PASMCs in vitro. Mechanistically, METTL3 depletion attenuated m6A modification and hindered the processing of pri-miR-143/145, leading to a downregulation of miR-143-3p and miR-145-5p. Inhibition of hnRNPA2B1, an m6A mediator involved in miRNA maturation, similarly resulted in a significant reduction of miR-143-3p and miR-145-5p. We demonstrated that miR-145-5p targets Krüppel-like factor 4 (KLF4) and miR-143-3p targets fascin actin-bundling protein 1 (FSCN1) in PASMCs. The decrease of miR-145-5p subsequently induced an upregulation of KLF4, which in turn suppressed miR-143/145 transcription, establishing a positive feedback circuit between KLF4 and miR-143/145. This regulatory circuit facilitates the persistent suppression of contractile marker genes, thereby sustaining PASMC phenotypic switch. Collectively, hypoxia-induced upregulation of METTL3, along with m6A mediated regulation of miR-143/145, might serve as a protective mechanism against phenotypic switch of PASMCs. Our results highlight a potential therapeutic strategy targeting m6A modified miR-143/145-KLF4 loop in the treatment of PH.

Intrinsic Gata4 expression sensitizes the aortic root to dilation in a Loeys-Dietz syndrome mouse model

Loeys-Dietz syndrome (LDS) is an aneurysm disorder caused by mutations that decrease transforming growth factor-β (TGF-β) signaling. Although aneurysms develop throughout the arterial tree, the aortic root is a site of heightened risk. To identify molecular determinants of this vulnerability, we investigated the heterogeneity of vascular smooth muscle cells (VSMCs) in the aorta of Tgfbr1 M318R/+ LDS mice by single cell and spatial transcriptomics. Reduced expression of components of the extracellular matrix-receptor apparatus and upregulation of stress and inflammatory pathways were observed in all LDS VSMCs. However, regardless of genotype, a subset of Gata4-expressing VSMCs predominantly located in the aortic root intrinsically displayed a less differentiated, proinflammatory profile. A similar population was also identified among aortic VSMCs in a human scRNAseq dataset. Postnatal VSMC-specific Gata4 deletion reduced aortic root dilation in LDS mice, suggesting that this factor sensitizes the aortic root to the effects of impaired TGF-β signaling.

High estrogen induces trans-differentiation of vascular smooth muscle cells to a macrophage-like phenotype resulting in aortic inflammation via inhibiting VHL/HIF1a/KLF4 axis

Estrogen is thought to have a role in slowing down aging and protecting cardiovascular and cognitive function. However, high doses of estrogen are still positively associated with autoimmune diseases and tumors with systemic inflammation. First, we administered exogenous estrogen to female mice for three consecutive months and found that the aorta of mice on estrogen develops inflammatory manifestations similar to Takayasu arteritis (TAK). Then, in vitro estrogen intervention was performed on mouse aortic vascular smooth muscle cells (MOVAS cells). Stimulated by high concentrations of estradiol, MOVAS cells showed decreased expression of contractile phenotypic markers and increased expression of macrophage-like phenotypic markers. This shift was blocked by tamoxifen and Krüppel-like factor 4 (KLF4) inhibitors and enhanced by Von Hippel-Lindau (VHL)/hypoxia-inducible factor-1α (HIF-1α) interaction inhibitors. It suggests that estrogen-targeted regulation of the VHL/HIF-1α/KLF4 axis induces phenotypic transformation of vascular smooth muscle cells (VSMC). In addition, estrogen-regulated phenotypic conversion of VSMC to macrophages is a key mechanism of estrogen-induced vascular inflammation, which justifies the risk of clinical use of estrogen replacement therapy.

Primary Mouse Aortic Smooth Muscle Cells Exhibit Region- and Sex-Dependent Biological Responses In Vitro

Despite advancements in elucidating biological mechanisms of cardiovascular remodeling, cardiovascular disease (CVD) remains the leading cause of death worldwide. When stratified by sex, clear differences in CVD prevalence and mortality between males and females emerge. Regional differences in phenotype and biological response of cardiovascular cells are important for localizing the initiation and progression of CVD. Thus, to better understand region and sex differences in CVD presentation, we have focused on characterizing in vitro behaviors of primary vascular smooth muscle cells (VSMCs) from the thoracic and abdominal aorta of male and female mice. VSMC contractility was assessed by traction force microscopy (TFM; single cell) and collagen gel contraction (collective) with and without stimulation by transforming growth factor-beta 1 (TGF-β1) and cell proliferation was assessed by a colorimetric metabolic assay (MTT). Gene expression and TFM analysis revealed region- and sex-dependent behaviors, whereas collagen gel contraction was consistent across sex and aortic region under baseline conditions. Thoracic VSMCs showed a sex-dependent sensitivity to TGF-β1-induced collagen gel contraction (female > male; p = 0.025) and a sex-dependent proliferative response (female > male; p < 0.001) that was not apparent in abdominal VSMCs. Although primary VSMCs exhibit intrinsic region and sex differences in biological responses that may be relevant for CVD presentation, several factors-such as inflammation and sex hormones-were not included in this study. Such factors should be included in future studies of in vitro mechanobiological responses relevant to CVD differences in males and females.

Single-Nucleus Multiomic Analyses Identifies Gene Regulatory Dynamics of Phenotypic Modulation in Human Aneurysmal Aortic Root

Aortic root aneurysm is a potentially life-threatening condition that may lead to aortic rupture and is often associated with genetic syndromes, such as Marfan syndrome (MFS). Although studies with MFS animal models have provided valuable insights into the pathogenesis of aortic root aneurysms, this understanding of the transcriptomic and epigenomic landscape in human aortic root tissue remains incomplete. This knowledge gap has impeded the development of effective targeted therapies. Here, this study performs the first integrative analysis of single-nucleus multiomic (gene expression and chromatin accessibility) and spatial transcriptomic sequencing data of human aortic root tissue under healthy and MFS conditions. Cell-type-specific transcriptomic and cis-regulatory profiles in the human aortic root are identified. Regulatory and spatial dynamics during phenotypic modulation of vascular smooth muscle cells (VSMCs), the cardinal cell type, are delineated. Moreover, candidate key regulators driving the phenotypic modulation of VSMC, such as FOXN3, TEAD1, BACH2, and BACH1, are identified. In vitro experiments demonstrate that FOXN3 functions as a novel key regulator for maintaining the contractile phenotype of human aortic VSMCs through targeting ACTA2. These findings provide novel insights into the regulatory and spatial dynamics during phenotypic modulation in the aneurysmal aortic root of humans.

Targeting deubiquitinase OTUB1 protects vascular smooth muscle cells in atherosclerosis by modulating PDGFRβ

Atherosclerosis is a chronic artery disease that causes various types of cardiovascular dysfunction. Vascular smooth muscle cells (VSMCs), the main components of atherosclerotic plaque, switch from contractile to synthetic phenotypes during atherogenesis. Ubiquitylation is crucial in regulating VSMC phenotypes in atherosclerosis, and it can be reversely regulated by deubiquitinases. However, the specific effects of deubiquitinases on atherosclerosis have not been thoroughly elucidated. In this study, RNAi screening in human aortic smooth muscle cells was performed to explore the effects of OTU family deubiquitinases, which revealed that silencing OTUB1 inhibited PDGF-BB-stimulated VSMC phenotype switch. Further in vivo studies using Apoe-/- mice revealed that knockdown of OTUB1 in VSMCs alleviated atherosclerosis plaque burden in the advanced stage and led to a stable plaque phenotype. Moreover, VSMC proliferation and migration upon PDGF-BB stimulation could be inhibited by silencing OTUB1 in vitro. Unbiased RNA-sequencing data indicated that knocking down OTUB1 influenced VSMC differentiation, adhesion, and proliferation. Mass spectrometry of ubiquitinated protein confirmed that proteins related to cell growth and migration were differentially ubiquitylated. Mechanistically, we found that OTUB1 recognized the K707 residue ubiquitylation of PDGFRβ with its catalytic triad, thereby reducing the K48-linked ubiquitylation of PDGFRβ. Inhibiting OTUB1 in VSMCs could promote PDGFRβ degradation via the ubiquitin-proteasome pathway, so it was beneficial in preventing VSMCs' phenotype switch. These findings revealed that knocking down OTUB1 ameliorated VSMCs' phenotype switch and atherosclerosis progression, indicating that OTUB1 could be a valuable translational therapeutic target in the future.

Vascular smooth muscle cell-specific Igf1r deficiency exacerbates the development of hypertension-induced cerebral microhemorrhages and gait defects

Cerebrovascular fragility and cerebral microhemorrhages (CMH) contribute to age-related cognitive impairment, mobility defects, and vascular cognitive impairment and dementia, impairing healthspan and reducing quality of life in the elderly. Insulin-like growth factor 1 (IGF-1) is a key vasoprotective growth factor that is reduced during aging. Circulating IGF-1 deficiency leads to the development of CMH and other signs of cerebrovascular dysfunction. Here our goal was to understand the contribution of IGF-1 signaling on vascular smooth muscle cells (VSMCs) to the development of CMH and associated gait defects. We used an inducible VSMC-specific promoter and an IGF-1 receptor (Igf1r) floxed mouse line (Myh11-CreERT2 Igf1rf/f) to knockdown Igf1r. Angiotensin II in combination with L-NAME-induced hypertension was used to elicit CMH. We observed that VSMC-specific Igf1r knockdown mice had accelerated development of CMH, and subsequent associated gait irregularities. These phenotypes were accompanied by upregulation of a cluster of pro-inflammatory genes associated with VSMC maladaptation. Collectively our findings support an essential role for VSMCs as a target for the vasoprotective effects of IGF-1, and suggest that VSMC dysfunction in aging may contribute to the development of CMH.

Anemoside B4 attenuates abdominal aortic aneurysm by limiting smooth muscle cell transdifferentiation and its mediated inflammation

Abdominal aortic aneurysm (AAA) is a degenerative disease characterized by local abnormal dilation of the aorta accompanied by vascular smooth muscle cell (VSMC) dysfunction and chronic inflammation. VSMC dedifferentiation, transdifferentiation, and increased expression of matrix metalloproteinases (MMPs) are essential causes of AAA formation. Previous studies from us and others have shown that Anemoside B4 (AB4), a saponin from Pulsatilla chinensis, has anti-inflammatory, anti-tumor, and regulatory effects on VSMC dedifferentiation. The current study aimed to investigate whether AB4 inhibits AAA development and its underlying mechanisms. By using an Ang II induced AAA model in vivo and cholesterol loading mediated VSMC to macrophage transdifferentiation model in vitro, our study demonstrated that AB4 could attenuate AAA pathogenesis, prevent VSMC dedifferentiation and transdifferentiation to macrophage-like cells, decrease vascular inflammation, and suppress MMP expression and activity. Furthermore, KLF4 overexpression attenuated the effects of AB4 on VSMC to macrophage-like cell transition and VSMC inflammation in vitro. In conclusion, AB4 protects against AAA formation in mice by inhibiting KLF4 mediated VSMC transdifferentiation and inflammation. Our study provides the first proof of concept of using AB4 for AAA management.

Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair

Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21+ cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21+ cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21+ cell clearance did not alter bone loss due to aging; conversely, p16+ cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21+ neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21+ OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell-like OCH subset that was p21+ and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells were key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings established contextual roles of p21+ versus p16+ senescent/senescent-like cells that may be leveraged for therapeutic opportunities.

Elucidating VSMC phenotypic transition mechanisms to bridge insights into cardiovascular disease implications

Cardiovascular diseases (CVD) are the leading cause of death worldwide, despite advances in understanding cardiovascular health. Significant barriers still exist in effectively preventing and managing these diseases. Vascular smooth muscle cells (VSMCs) are crucial for maintaining vascular integrity and can switch between contractile and synthetic functions in response to stimuli such as hypoxia and inflammation. These transformations play a pivotal role in the progression of cardiovascular diseases, facilitating vascular modifications and disease advancement. This article synthesizes the current understanding of the mechanisms and signaling pathways regulating VSMC phenotypic transitions, highlighting their potential as therapeutic targets in cardiovascular disease interventions.

Single-Cell Analyses Offer Insights into the Different Remodeling Programs of Arteries and Veins

Arteries and veins develop different types of occlusive diseases and respond differently to injury. The biological reasons for this discrepancy are not well understood, which is a limiting factor for the development of vein-targeted therapies. This study contrasts human peripheral arteries and veins at the single-cell level, with a focus on cell populations with remodeling potential. Upper arm arteries (brachial) and veins (basilic/cephalic) from 30 organ donors were compared using a combination of bulk and single-cell RNA sequencing, proteomics, flow cytometry, and histology. The cellular atlases of six arteries and veins demonstrated a 7.8× higher proportion of contractile smooth muscle cells (SMCs) in arteries and a trend toward more modulated SMCs. In contrast, veins showed a higher abundance of endothelial cells, pericytes, and macrophages, as well as an increasing trend in fibroblasts. Activated fibroblasts had similar proportions in both types of vessels but with significant differences in gene expression. Modulated SMCs and activated fibroblasts were characterized by the upregulation of MYH10, FN1, COL8A1, and ITGA10. Activated fibroblasts also expressed F2R, POSTN, and COMP and were confirmed by F2R/CD90 flow cytometry. Activated fibroblasts from veins were the top producers of collagens among all fibroblast populations from both types of vessels. Venous fibroblasts were also highly angiogenic, proinflammatory, and hyper-responders to reactive oxygen species. Differences in wall structure further explain the significant contribution of fibroblast populations to remodeling in veins. Fibroblasts are almost exclusively located outside the external elastic lamina in arteries, while widely distributed throughout the venous wall. In line with the above, ECM-targeted proteomics confirmed a higher abundance of fibrillar collagens in veins vs. more basement ECM components in arteries. The distinct cellular compositions and transcriptional programs of reparative populations in arteries and veins may explain differences in acute and chronic wall remodeling between vessels. This information may be relevant for the development of antistenotic therapies.

KLF13 promotes VSMCs phenotypic dedifferentiation by directly binding to the SM22α promoter

Krüppel-like factor 13 (KLF13), a zinc finger transcription factor, is considered as a potential regulator of cardiomyocyte differentiation and proliferation during heart morphogenesis. However, its precise role in the dedifferentiation of vascular smooth muscle cells (VSMCs) during atherosclerosis and neointimal formation after injury remains poorly understood. In this study, we investigated the relationship between KLF13 and SM22α expression in normal and atherosclerotic plaques by bioanalysis, and observed a significant increase in KLF13 levels in the atherosclerotic plaques of both human patients and ApoE-/- mice. Knockdown of KLF13 was found to ameliorate intimal hyperplasia following carotid artery injury. Furthermore, we discovered that KLF13 directly binds to the SM22α promoter, leading to the phenotypic dedifferentiation of VSMCs. Remarkably, we observed a significant inhibition of platelet-derived growth factor BB-induced VSMCs dedifferentiation, proliferation, and migration when knocked down KLF13 in VSMCs. This inhibitory effect of KLF13 knockdown on VCMC function was, at least in part, mediated by the inactivation of p-AKT signaling in VSMCs. Overall, our findings shed light on a potential therapeutic target for treating atherosclerotic lesions and restenosis after vascular injury.

Mechanical stress induced mitochondrial dysfunction in cardiovascular diseases: Novel mechanisms and therapeutic targets

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. Others and our studies have shown that mechanical stresses (forces) including shear stress and cyclic stretch, occur in various pathological conditions, play significant roles in the development and progression of CVDs. Mitochondria regulate the physiological processes of cardiac and vascular cells mainly through adenosine triphosphate (ATP) production, calcium flux and redox control while promote cell death through electron transport complex (ETC) related cellular stress response. Mounting evidence reveal that mechanical stress-induced mitochondrial dysfunction plays a vital role in the pathogenesis of many CVDs including heart failure and atherosclerosis. This review summarized mitochondrial functions in cardiovascular system under physiological mechanical stress and mitochondrial dysfunction under pathological mechanical stress in CVDs (graphical abstract). The study of mitochondrial dysfunction under mechanical stress can further our understanding of the underlying mechanisms, identify potential therapeutic targets, and aid the development of novel treatments of CVDs.

Ovariectomy-Induced Arterial Stiffening Differs From Vascular Aging and Is Reversed by GPER Activation

BACKGROUND

Arterial stiffness is a cardiovascular risk factor and dramatically increases as women transition through menopause. The current study assessed whether a mouse model of menopause increases arterial stiffness in a similar manner to aging and whether activation of the G-protein-coupled estrogen receptor could reverse stiffness.

METHODS

Female C57Bl/6J mice were ovariectomized at 10 weeks of age or aged to 52 weeks, and some mice were treated with G-protein-coupled estrogen receptor agonists.

RESULTS

Ovariectomy and aging increased pulse wave velocity to a similar extent independent of changes in blood pressure. Aging increased carotid wall thickness, while ovariectomy increased material stiffness without altering vascular geometry. RNA-sequencing analysis revealed that ovariectomy downregulated smooth muscle contractile genes. The enantiomerically pure G-protein-coupled estrogen receptor agonist, LNS8801, reversed stiffness in ovariectomy mice to a greater degree than the racemic agonist G-1. In summary, ovariectomy and aging induced arterial stiffening via potentially different mechanisms. Aging was associated with inward remodeling, while ovariectomy-induced material stiffness independent of geometry and a loss of the contractile phenotype.

CONCLUSIONS

This study enhances our understanding of the impact of estrogen loss on vascular health in a murine model and warrants further studies to examine the ability of LNS8801 to improve vascular health in menopausal women.

Transcriptome analysis reveals therapeutic potential of NAMPT in protecting against abdominal aortic aneurysm in human and mouse

Abdominal Aortic Aneurysm (AAA) is a life-threatening vascular disease characterized by the weakening and ballooning of the abdominal aorta, which has no effective therapeutic approaches due to unclear molecular mechanisms. Using single-cell RNA sequencing, we analyzed the molecular profile of individual cells within control and AAA abdominal aortas. We found cellular heterogeneity, with increased plasmacytoid dendritic cells and reduced endothelial cells and vascular smooth muscle cells (VSMCs) in AAA. Up-regulated genes in AAA were associated with muscle tissue development and apoptosis. Genes controlling VSMCs aberrant switch from contractile to synthetic phenotype were significantly enriched in AAA. Additionally, VSMCs in AAA exhibited cell senescence and impaired oxidative phosphorylation. Similar observations were made in a mouse model of AAA induced by Angiotensin II, further affirming the relevance of our findings to human AAA. The concurrence of gene expression changes between human and mouse highlighted the impairment of oxidative phosphorylation as a potential target for intervention. Nicotinamide phosphoribosyltransferase (NAMPT, also named VISFATIN) signaling emerged as a signature event in AAA. NAMPT was significantly downregulated in AAA. NAMPT-extracellular vesicles (EVs) derived from mesenchymal stem cells restored NAMPT levels, and offered protection against AAA. Furthermore, NAMPT-EVs not only repressed injuries, such as cell senescence and DNA damage, but also rescued impairments of oxidative phosphorylation in both mouse and human AAA models, suggesting NAMPT supplementation as a potential therapeutic approach for AAA treatment. These findings shed light on the cellular heterogeneity and injuries in AAA, and offered promising therapeutic intervention for AAA treatment.

Dysregulated cellular metabolism in atherosclerosis: mediators and therapeutic opportunities

Accumulating evidence over the past decades has revealed an intricate relationship between dysregulation of cellular metabolism and the progression of atherosclerotic cardiovascular disease. However, an integrated understanding of dysregulated cellular metabolism in atherosclerotic cardiovascular disease and its potential value as a therapeutic target is missing. In this Review, we (1) summarize recent advances concerning the role of metabolic dysregulation during atherosclerosis progression in lesional cells, including endothelial cells, vascular smooth muscle cells, macrophages and T cells; (2) explore the complexity of metabolic cross-talk between these lesional cells; (3) highlight emerging technologies that promise to illuminate unknown aspects of metabolism in atherosclerosis; and (4) suggest strategies for targeting these underexplored metabolic alterations to mitigate atherosclerosis progression and stabilize rupture-prone atheromas with a potential new generation of cardiovascular therapeutics.

Aortic Cellular Heterogeneity in Health and Disease: Novel Insights Into Aortic Diseases From Single-Cell RNA Transcriptomic Data Sets

Aortic diseases such as atherosclerosis, aortic aneurysms, and aortic stiffening are significant complications that can have significant impact on end-stage cardiovascular disease. With limited pharmacological therapeutic strategies that target the structural changes in the aorta, surgical intervention remains the only option for some patients with these diseases. Although there have been significant contributions to our understanding of the cellular architecture of the diseased aorta, particularly in the context of atherosclerosis, furthering our insight into the cellular drivers of disease is required. The major cell types of the aorta are well defined; however, the advent of single-cell RNA sequencing provides unrivaled insights into the cellular heterogeneity of each aortic cell type and the inferred biological processes associated with each cell in health and disease. This review discusses previous concepts that have now been enhanced with recent advances made by single-cell RNA sequencing with a focus on aortic cellular heterogeneity.