Smooth Muscle Cell Phenotypic Switching Research Articles

Abstract 4134531: BST2 induces vascular smooth muscle cell plasticity and phenotype switching during cancer progression

Rationale: Smooth muscle cell (SMC) plasticity and phenotypic switching play prominent roles in the pathogenesis of multiple diseases like atherosclerosis and pulmonary hypertension, but their role in tumorigenesis is unknown. Objective: To investigate SMC diversity and plasticity in tumor angiogenesis and its underlying molecular drivers. Methods and Results: Here we use SMC-specific lineage-tracing mouse models and single cell RNA sequencing (scRNA-seq) to observe the phenotypic diversity of SMCs participating in tumor vascularization. We find that around 10% of SMCs adopt a phenotype which includes features traditionally associated with macrophage-like cells, suggesting they may contribute to the immune profile of the tumor microenvironment (TME). These cells are transcriptionally similar to ‘resolution phase’ M2b macrophages, which have been described to have a role in inflammation resolution. Signaling from bone marrow stromal antigen 2 (BST2) on the surface of tumor cells to PIRA2 on SMC promotes this phenotypic transition, leading to a SMC phenotype that is more proliferative, migratory, and phagocytic. Knockdown of BST2 in the tumor significantly decreases the transition towards a macrophage-like phenotype, and the cells that were able to transition had a comparatively higher inflammatory signal typically associated with anti-tumor effect. Conclusions: As BST2 is known to be a poor prognostic marker in multiple cancers where it is associated with an M2 macrophage-skewed TME, these studies suggest that phenotypically switched SMCs may have a previously unidentified role in this immunosuppressive milieu. The novel concept of SMC contribution to the immune landscape suggests manipulation of SMC phenotypic switching as an approach to altering cancer pathogenesis. Further translational work is needed to understand how this phenotypic switch could influence response to anti-cancer agents and if targeted inhibition of SMC plasticity would be therapeutically beneficial.

MicroRNA-18a-5p promotes vascular smooth muscle cell phenotypic switch by targeting Notch2 as therapeutic targets in vein grafts restenosis

Vascular smooth muscle cells (VSMCs) phenotype switching plays a crucial role in vein graft restenosis following coronary artery bypass grafting (CABG) surgery. To discover novel clinically relevant therapeutic targets for vein graft restenosis after CABG, we therefore investigated whether miRNA-18a-5p mediated phenotype switching plays a critical role in the development of vein graft restenosis. We studied miRNA-18a-5p expression in plasma samples of patients with or without vein graft restenosis at 1, 3 and 5 years after coronary artery bypass graft surgery, and in normal vs. atherosclerotic human femoral artery samples, to prove its role in VSMC phenotype switching. We found that the expression of miRNA-18a-5p significantly increased in vein grafts restenosis rat model after bypass surgery at 7, 14, 28 days and human blood specimens with vein grafts failure after grafting surgery. Through gain- and loss-of-function approaches, we determined that miRNA-18a-5p affects VSMC proliferation, migration, differentiation, and contractility. Notch2 was found to be a direct target of miRNA-18a-5p, which is critical for VSMC phenotype switching. Finally, miRNA-18a-5p knockdown used miRNA sponge via AAV6 locally delivery in vivo, miRNA-18a-5p sponge gene transfer therapy reduced the neointimal area, neointimal thickness, and intimal/media area ratio in vein grafts compared with the controls and improved vein graft hemodynamics. miRNA-18a-5p is a critical modulator of VSMC phenotypic switch during development of vein graft restenosis by downregulating Notch2, therefore targeting miRNA-18a-5p may be a helpful strategy for the treatment of vein grafts restenosis or failure after CABG surgery.

Smooth muscle cell-specific deletion of S100A4 modifies smooth muscle cell fate and inflammation in murine atherosclerotic lesions

Abstract Background S100A4, a calcium-binding protein, is crucial in smooth muscle cell (SMC) phenotypic switch, yet its role in atherosclerotic plaque development and SMC plasticity remains unclear. Our previous experiments using an S100A4 neutralizing antibody approach in ApoE-/- atherosclerotic-prone mice showed reduced atherosclerotic burden but did not establish a direct link between the various S100A4-expressing cells and atherosclerosis. Methods/Results Herein, we show that aortic Oil RedO staining in ApoE-/-; S100A4-/- mice subjected to a 12-week high-cholesterol-diet (HCD) revealed reduced lesion areas compared to ApoE-/- mice (Figure 1, from 21.29% of the total aorta in ApoE-/-; S100A4+/+ mice to 13.27% in ApoE-/-; S100A4-/- mice), highlighting a pivotal role for S100A4 in atherosclerotic plaque development. We then used a lineage tracing ApoE-/- mouse model, in which we induced an SMC-specific deletion of S100A4 (SMC-S100A4Δ/Δ). After 12 weeks of HCD, SMC-S100A4Δ/Δ and control mice (SMC-S100A4wt/wt) were sacrificed, and aortas were processed for en face Oil Red O staining, immunohistochemistry, and single-cell RNA sequencing (scRNA-seq). SMC-specific deletion of S100A4 reduced the necrotic core area (from 29.75% of total plaque area in SMC-S100A4wt/wt to 18.23% in SMC-S100A4Δ/Δ mice) without affecting total atherosclerotic plaque size suggesting a more potent impact on plaque composition. ScRNA-seq analysis from SMC-S100A4Δ/Δ and SMC-S100A4wt/wt mice showed that the inflammatory macrophage-like SMC phenotype was highly suppressed in the plaque and associated with increased SMC repair phenotypes as well as a global reduction of myeloid inflammatory cells. SMCs also retained specific contractile SMC markers, namely Acta2 and Myh11 (fold change of 2.285 and 2.492, respectively) hinting towards a more stable fibrous cap. Immunofluorescence staining on aortic roots plaque (Figure 2) confirmed those results with an increase of SMCs (from 11.02% to 16.18%) as well as a-smooth muscle actin (a-SMA, Acta2)-positive SMCs (from 3.25% to 5.1%) in SMC-S100A4 Δ/Δ mice. Furthermore, the Gene Set Enrichment Analysis (GSEA) of scRNAseq data revealed that, in SMC-S100A4Δ/Δ mice, genes related to mitochondrial metabolism and oxidative respiration were highly downregulated in all SMC clusters. We investigated SMC mitochondrial fitness in vitro and showed that S100A4-/- SMCs have an increased basal oxygen consumption rate and an increased proton leak (fold change of 1.37 and 1.96 respectively) suggestive of differences in cellular metabolic adaptability. Conclusion Our research emphasizes the significant role of S100A4 in plaque development, demonstrating how SMC-derived S100A4 knockdown affects plaque evolution, reducing inflammation, and promoting stability likely through influencing SMC phenotypic switch through metabolic pathways.

NAT10 promotes vascular remodelling via mRNA ac4C acetylation.

Vascular smooth muscle cell (VSMC) phenotype switching is a pathological hallmark in various cardiovascular diseases. N4-acetylcytidine (ac4C) catalyzed by N-acetyltransferase 10 (NAT10) is well conserved in the enzymatic modification of ribonucleic acid (RNA). NAT10-mediated ac4C acetylation is involved in various physiological and pathological processes, including cardiac remodelling. However, the biological functions and underlying regulatory mechanisms of mRNA ac4C modifications in vascular diseases remain elusive. By combining in-vitro and in-vivo vascular injury models, NAT10 was identified as a crucial protein involved in the promotion of post-injury neointima formation, as well as VSMC phenotype switching. The potential mechanisms of NAT10 in the vascular neointima formation were clarified by RNA sequence (RNA-seq), acetylated mRNA immunoprecipitation sequence (acRIP-seq), and RNA binding protein immunoprecipitation sequence (RIP-seq). NAT10 and ac4C modifications were upregulated in injured human and rodent arteries. Deletion of NAT10 in VSMCs effectively reduced post-injury neointima formation and VSMC phenotype switching. Further RNA-seq, RIP-seq, and acRIP-seq revealed that NAT10, by its ac4C modification, directly interacts with genes, including integrin-β1 (ITGB1) and collagen type I alpha 2 chain (Col1a2) mRNAs. Taking ITGB1 as one example, it showed that NAT10-mediated ac4C consequently increased ITGB1 mRNA stability and its downstream focal adhesion kinase (FAK) signaling, directly influencing the proliferation of VSMCs and vascular remodelling. The regulation of NAT10 on the VSMC phenotype is of translational significance because the administration of Remodelin, a NAT10 inhibitor, effectively prevents neointima formation by suppressing VSMC proliferation and downregulating ITGB1 expression and deactivating its FAK signaling. This study reveals that NAT10 promotes vascular remodelling via mRNA ac4C acetylation, which may be a promising therapeutic target against vascular remodelling.

Anti-atherosclerotic effect of incretin receptor agonists.

Incretin receptor agonists (IRAs), primarily composed of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and glucose-dependent insulinotropic polypeptide receptor agonists (GIPRAs), work by mimicking the actions of the endogenous incretin hormones in the body. GLP-1RAs have been approved for use as monotherapy and in combination with GIPRAs for the management of type 2 diabetes mellitus (T2DM). In addition to their role in glucose regulation, IRAs have demonstrated various benefits such as cardiovascular protection, obesity management, and regulation of bone turnover. Some studies have suggested that IRAs not only aid in glycemic control but also exhibit anti-atherosclerotic effects. These agents have been shown to modulate lipid abnormalities, reduce blood pressure, and preserve the structural and functional integrity of the endothelium. Furthermore, IRAs have the ability to mitigate inflammation by inhibiting macrophage activation and promoting M2 polarization. Research has also indicated that IRAs can decrease macrophage foam cell formation and prevent vascular smooth muscle cell (VSMC) phenotype switching, which are pivotal in atheromatous plaque formation and stability. This review offers a comprehensive overview of the protective effects of IRAs in atherosclerotic disease, with a focus on their impact on atherogenesis.

Reduction of Abdominal Aortic Aneurysm Rupture By Modulating Smooth Muscle Cell Phenotype Switching

Reduction of Abdominal Aortic Aneurysm Rupture By Modulating Smooth Muscle Cell Phenotype Switching

Early growth response 1 exacerbates thoracic aortic aneurysm and dissection of mice by inducing the phenotypic switching of vascular smooth muscle cell through the activation of Krüppel-like factor 5.

Vascular smooth muscle cell (VSMC) phenotypic switching has been reported to regulate vascular function and thoracic aortic aneurysm and dissection (TAAD) progression. Early growth response 1 (Egr1) is associated with the differentiation of VSMCs. However, the mechanisms through which Egr1 participates in the regulation of VSMCs and progression of TAAD remain unknown. This study aimed to investigate the role of Egr1 in the phenotypic switching of VSMCs and the development of TAAD. Wild-type C57BL/6 and SMC-specific Egr1-knockout mice were used as experimental subjects and fed β-aminopropionitrile for 4 weeks to construct the TAAD model. Ultrasound and aortic staining were performed to examine the pathological features in thoracic aortic tissues. Transwell, wound healing, CCK8, and immunofluorescence assays detected the migration and proliferation of synthetic VSMCs. Egr1 was directly bound to the promoter of Krüppel-like factor 5 (KLF5) and promoted the expression of KLF5, which was validated by JASPAR database and dual-luciferase reporter assay. Egr1 expression increased and was partially co-located with VSMCs in aortic tissues of mice with TAAD. SMC-specific Egr1 deficiency alleviated TAAD and inhibited the phenotypic switching of VSMC. Egr1 knockdown prevented the phenotypic switching of VSMCs and subsequently suppressed the migration and proliferation of synthetic VSMCs. The inhibitory effects of Egr1 deficiency on VSMCs were blunted once KLF5 was overexpressed. Egr1 aggravated the development of TAAD by promoting the phenotypic switching of VSMCs via enhancing the transcriptional activation of KLF5. These results suggest that inhibition of SMC-specific Egr1 expression is a promising therapy for TAAD.

Matrix vesicles from osteoblasts promote atherosclerotic calcification

Atherosclerotic calcification often coincides with osteoporosis, suggesting a potential interplay between bone and vascular mineralization. Osteoblast-derived matrix vesicles (Ost-MVs), pivotal in bone mineralization, have emerged as potential contributors to ectopic vascular calcification. However, the precise role of Ost-MVs in vascular calcification and the underlying mechanisms remain elusive. In this study, we observed a concomitant increase in atherosclerotic calcification and bone loss, accompanied by elevated release of Ost-MVs into circulation. We demonstrate that circulating Ost-MVs target plaque lesions in the setting of atherosclerosis. Mechanistically, vascular injury facilitates transendothelial transport of Ost-MVs, collagen І remodeling promotes Ost-MVs aggregation, and vascular smooth muscle cell (VSMC) phenotypic switching enhances MV uptake. These pathological changes during atherosclerosis collectively contribute to Ost-MVs recruitment into the vasculature. Furthermore, Ost-MVs and VSMC-derived matrix vesicles (VSMC-MVs) exacerbate calcification via the Ras-Raf-ERK pathway. Our findings unveil a novel Ost-MVs-mediated mechanism participating in vascular calcification and enriching our understanding of bone-vascular crosstalk.

F-53B stimulated vascular smooth muscle cell phenotypic switch and vascular remodeling via ferroptosis-related pathway

The compound 6:2 chlorinated polyfluorinated ether sulfonate (F53B), an alternative to perfluorooctane sulfonate (PFOS), has been widely utilized in China. Although the connection between the exposure and toxicity of F53B is established, the role and mechanisms of the compound in promoting vascular remodeling are yet to be elucidated. Thus, the present study investigated the impact of F53B on the function of vascular smooth muscle cells (VSMCs) and vascular remodeling. The data exhibited that F53B stimulates vascular morphological alterations in vivo, and exposure to the compound caused excessive VSMCs ferroptosis and phenotype switching, as determined using phenotype and molecular assays. Moreover, Fer-1 reversed F-53B-induced VSMC dysfunction and vascular remodeling. Furthermore, F53B activated the ferroptosis-related pathway, encompassing ATR expression and LOC101929922/miR-542-3p/ACSL4 pathway. Thus, the current results elaborated on the multifaceted toxicities of F53B that induce vascular remodeling, thereby necessitating the assessment of vasotoxicity risks associated with the compound.

ACE2 deficiency inhibits thoracic aortic dissection by enhancing SIRT3 mediated inhibition of inflammation and VSCMs phenotypic switch

BackgroundThoracic aortic dissection (TAD) is an irreversible cardiovascular disorder with high mortality and morbidity. However, the molecular mechanisms remain elusive. Thus, identifying an effective therapeutic target to prevent TAD is especially critical. The purpose of this study is to elucidate the potential mechanism of inflammation and vascular smooth muscle cell (VSMCs) phenotypic switch in β-aminopropionitrile fumarate (BAPN)-induced TAD.MethodsA mouse model of TAD induced by BAPN and IL-1β -stimulated HVSMCs in vivo and in vitro models, respectively. ACE2 Knockdown mice treated with BAPN or without, and the TAD mouse model was treated with or without AAV-ACE2. Transthoracic ultrasound was conducted for assessment the maximum internal diameter of the thoracic aorta arch. RNA sequencing analysis was performed to recapitulate transcriptome profile changes. Western blot were used to detect the expression of MMP2, MMP9, ACE2, SIRT3, OPN, SM22α and other inflammatory markers. The circulating levels of ACE2 was measured by ELISA assay. Histological changes of thoracic aorta tissues were assessed by H&E, EVG and IHC analysis.ResultsWe found that circulating levels of and the protein levels of ACE2 were increased in the TAD mouse model and in patients with TAD. For further evidence, ACE2 deficiency decelerated the formation of TAD. However, overexpression of ACE2 aggravated BAPN-induced aortic injury and VSMCs phenotypic switch via lowered SIRT3 expression and elevated inflammatory cytokine expression.ConclusionACE2 deficiency prevented the development of TAD by inhibiting inflammation and VSMCs phenotypic switch in a SIRT3-dependent manner, suggesting that the ACE2/SIRT3 signaling pathway played a pivotal role in the pathological process of TAD and might be a potential therapeutical target.

NONRATT000538.2 promotes vascular smooth muscle cell phenotypic switch and in-stent restenosis

Vascular smooth muscle cell (VSMC) excessive proliferation and migration are considered the main pathological process in in-stent restenosis (ISR) following vascular intervention. Certain long noncoding RNAs play vital roles in this process. Therefore, this study aimed to explore novel regulators for ISR and further uncover the mechanism. Using a rat abdominal aorta stent implantation model, we observed that NONRATT000538.2 (NR538.2) served as a positive regulator for VSMC proliferation and migration. By manipulating NR538.2 expression via adenoviral overexpression or siRNA knockdown, we noted that NR538.2 promoted VSMC phenotypic switching, thereby inducing proliferation and migration. Significantly, the local delivery of siRNA of NR538.2 via adeno-associated virus vector suppressed balloon injury-induced neointima formation. Our study demonstrated for the first time that NR538.2 positively influenced VSMC proliferation during ISR.

Exosomes derived from hypoxic alveolar epithelial cells promote the phenotypic transformation of pulmonary artery smooth muscle cells via the Rap1 pathway

Background: Hypoxic pulmonary hypertension (HPH) is one of the important pathophysiological changes in chronic pulmonary heart disease. Hypoxia promotes the phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs). Extracellular exosomes regulate vascular smooth muscle cell (VSMC) phenotypic switch. Aim: Given the importance of exosomes and alveolar epithelial cells (AECs) in HPH, the present study aimed to address the issue of whether AEC-derived exosomes promote HPH by triggering PASMC phenotypic switch. Methods: Cell Counting Kit-8 (CCK-8), TRITC-phalloidin staining, and Western blotting were used to examine the effects of AEC-derived exosomes on cell proliferation, intracellular actin backbone distribution, and expression of phenotypic marker proteins in PASMCs. Transcriptomics sequencing was used to analyze differentially expressed genes (DEGs) between groups. Results: Hypoxia-induced exosomes (H-exos) could promote the proliferation of PASMCs, cause the reduction of cellular actin microfilaments, promote the expression of synthetic marker proteins (ELN and OPN), reduce the expression of contractile phenotypic marker proteins (SM22-α and α-SMA), and induce the phenotypic transformation of PASMCs. Transcriptomics sequencing analysis showed that the Rap1 signaling pathway was involved in the phenotypic transformation of PASMCs induced by H-exos. Conclusion: The present study identified that hypoxia-induced AEC-derived exosomes promote the phenotypic transformation of PASMCs and its mechanism is related to the Rap1 signaling pathway.

ScRNA‐seq reveals NAMPT‐mediated macrophage polarization shapes smooth muscle cell plasticity in pulmonary arterial hypertension

AbstractPhenotypic switching of smooth muscle cells (SMC) is a crucial process in the pathogenesis of pulmonary arterial hypertension (PAH). However, the underlying mechanism is unclear. Here, we performed single‐cell RNA sequencing on pulmonary arteries obtained from lung transplantation to explore the cellular heterogeneity and gene expression profile of the main cell types. We identified three distinct SMC phenotypes, namely contractile, fibroblast‐like, and chondroid‐like, and observed an enhanced transition from contractile to fibroblast‐like phenotype in PAH by pseudo‐time analysis and in vitro. We also revealed a classically activated (M1) polarization of macrophages and an increased pro‐inflammatory macrophage‐SMC crosstalk in PAH via intercellular communication. Notably, Nicotinamide phosphoribosyltransferase (NAMPT) emerges as a key player in macrophage polarization. The macrophages overexpress Nampt in Sugen/hypoxia (Su/Hx) ‐induced PAH mice and significantly downregulate the pro‐inflammation secretion pattern with Nampt interference. In a cellular coculture system, Nampt knockdown in macrophages significantly inhibits the fibroblast‐like phenotypic switching of SMCs. Finally, we identified Ccl2/5 as a key cytokine for SMC phenotypic modulation. Collectively, these findings provide a cell atlas of normal human pulmonary arteries and demonstrate that NAMPT‐driven M1 macrophage polarization promotes the fibroblast‐like phenotypic switching of SMCs through CCR2/CCR5 cellular crosstalk in PAH.

BST2 induces vascular smooth muscle cell plasticity and phenotype switching during cancer progression.

Smooth muscle cell (SMC) plasticity and phenotypic switching play prominent roles in the pathogenesis of multiple diseases, but their role in tumorigenesis is unknown. We investigated whether and how SMC diversity and plasticity plays a role in tumor angiogenesis and the tumor microenvironment. We use SMC-specific lineage-tracing mouse models and single cell RNA sequencing to observe the phenotypic diversity of SMCs participating in tumor vascularization. We find that a significant proportion of SMCs adopt a phenotype traditionally associated with macrophage-like cells. These cells are transcriptionally similar to 'resolution phase' M2b macrophages, which have been described to have a role in inflammation resolution. Computationally predicted by the ligand-receptor algorithm CellChat, signaling from BST2 on the surface of tumor cells to PIRA2 on SMCs promote this phenotypic transition; in vitro SMC assays demonstrate upregulation of macrophage transcriptional programs, and increased proliferation, migration, and phagocytic ability when exposed to BST2. Knockdown of BST2 in the tumor significantly decreases the transition towards a macrophage-like phenotype, and cells that do transition have a comparatively higher inflammatory signal typically associated with anti-tumor effect. As BST2 is known to be a poor prognostic marker in multiple cancers where it is associated with an M2 macrophage-skewed TME, these studies suggest that phenotypically switched SMCs may have a previously unidentified role in this immunosuppressive milieu. Further translational work is needed to understand how this phenotypic switch could influence the response to anti-cancer agents and if targeted inhibition of SMC plasticity would be therapeutically beneficial.

Angiopoietin-like 4 facilitates human aortic smooth muscle cell phenotype switch and dysfunctions through the PI3K/Akt signaling in aortic dissection

PurposeVascular smooth muscle cell (VSMC) phenotype switch and dysfunctions have been reported to participate in aortic dissection (AD) progression. This study was aimed to investigate the role of angiopoietin-like 4 (ANGPTL4) in regulating VSMCs phenotype switch. Materials and methodsKey genes were analyzed in AD using public datasets, and it was found that the central differential gene ANGPTL4 was up-regulated in AD. The KEGG signaling pathway annotation was performed to validate the associated pathways, and the expression of ANGPTL4 was verified using multiple datasets and clinical samples. Furthermore, the specific functions of ANGPTL4 on platelet-derived growth factor-BB (PDGF-BB)-treated human aortic smooth muscle cell (HASMC) phenotypes were investigated. The dynamic effects of ANGPTL4 and core signaling antagonists on HASMC phenotypes were examined. ResultsHub gene ANGPTL4 was significantly up-regulated in AD. ANGPTL4 was linked to the PI3K/Akt signaling, angiogenesis, and neovascularization and remodeling. ANGPTL4 overexpression further enhanced PDGF-BB effects on HASMC phenotypes, including promoted cell viability and migration, decreased contractile VSMC markers α-SMA and SM22α, elevated ECM degradation markers MMP-2 and MMP-9, and promoted phosphorylation of PI3K and Akt. ANGPTL4 knockdown partially abolished PDGF-BB-induced contractile/synthetic VSMCs imbalance and HASMC dysfunctions. Furthermore, in ANGPTL4-overexpressing HASMCs pre-treated with PDGF-BB, the PI3K/Akt signaling inhibitor LY294002 also partially eliminated the effects caused by the PDGF-BB treatment and ANGPTL4 overexpression. ConclusionsANGPTL4 is significantly up-regulated in AD. ANGPTL4 overexpression further enhanced PDGF-BB effects on HASMC phenotype switch and dysfunctions, which might be involved in the PI3K/Akt signaling.

CircSMAD3 represses VSMC phenotype switching and neointima formation via promoting hnRNPA1 ubiquitination degradation.

Circular RNAs (circRNAs) are novel regulatory RNAs with high evolutionary conservation and stability, which makes them effective therapeutic agents for various vascular diseases. The SMAD family is a downstream mediator of the canonical transforming growth factor beta (TGF-β) signalling pathway and has been considered as a critical regulator in vascular injury. However, the role of circRNAs derived from the SMAD family members in vascular physiology remains unclear. In this study, we initially identified potential functional circRNAs originating from the SMAD family using integrated transcriptome screening. circSMAD3, derived from the SMAD3 gene, was identified to be significantly downregulated in vascular injury and atherosclerosis. Transcriptome analysis was conducted to comprehensively illustrate the pathways modulated by circRNAs. Functionally, circSMAD3 repressed vascular smooth muscle cell (VSMC) proliferation and phenotype switching in vitro evidenced by morphological assays, and ameliorated arterial injury-induced neointima formation in vivo. Mechanistically, circSMAD3 interacted with heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) within the nucleus, enhanced its interaction with E3 ligase WD repeat domain 76 to promote hnRNPA1 ubiquitination degradation, facilitated p53 pre-RNA splicing, activated the p53γ signalling pathway, and finally suppressed VSMC proliferation and phenotype switching. Our study identifies circSMAD3 as a novel epigenetic regulator that suppresses VSMC proliferation and phenotype switching, thereby attenuating vascular remodelling and providing a new circRNA-based therapeutic strategy for cardiovascular diseases.

Circular RNA circ_0002984 Facilitates the Proliferation and Migration of Ox-LDL-Induced Vascular Smooth Muscle Cells via the Let-7a-5p/KLF5 Pathway.

Circular RNAs (circRNAs) play an important role in the progression of atherosclerosis (AS). This study aimed to explore the exact role and mechanism of circ_0002984 in oxidized low-density lipoprotein (ox-LDL)-mediated human vascular smooth muscle cells (HVSMCs). The model of smooth muscle cell phenotype switching was constructed by treating HVSMCs with ox-LDL. The levels of circ_0002984, let-7a-5p, and kruppel-like factor 5 (KLF5) were measured by quantitative real-time PCR or western blot assay. Cell proliferation, migration, and apoptosis were detected by Cell Counting Kit-8 (CCK-8), EdU staining, wound healing assay, transwell assay, and flow cytometry. The expression of cleaved-caspase-3 and KLF5 was examined by western blot. The relationship between let-7a-5p and circ_0002984 or KLF5 was verified by dual-luciferase reporter assay or RIP assay. The results showed thatcirc_0002984 and KLF5 were up-regulated, while let-7a-5p was down-regulated in AS patients and ox-LDL-disposed HVSMCs. Silence of circ_0002984 suppressed proliferation and migration, and promoted apoptosis in ox-LDL-stimulated HVSMCs. Moreover, circ_0002984 sponged let-7a-5p to regulate the proliferation, migration, and apoptosis in ox-LDL-resulted HVSMCs. In addition, KLF5 was a target of let-7a-5p and its overexpression reversed the effect of let-7a-5p on the proliferation, migration, and apoptosis in ox-LDL-treated HVSMCs. Also, circ_0002984 positively regulated KLF5 expression by absorbing let-7a-5p. The promotion effect of circ_0002984 on the proliferation and migration of ox-LDL-treated HVSMCs was reversed by KLF5 silencing. Taken together,depletion of circ_0002984 inhibited the proliferation and migration of ox-LDL-stimulated HVSMCs, which might be achieved by modulating the let-7a-5p/KLF5 axis.

Intravascular delivery of an MK2 inhibitory peptide to prevent restenosis after angioplasty

Peripheral artery disease is commonly treated with balloon angioplasty, a procedure involving minimally invasive, transluminal insertion of a catheter to the site of stenosis, where a balloon is inflated to open the blockage, restoring blood flow. However, peripheral angioplasty has a high rate of restenosis, limiting long-term patency. Therefore, angioplasty is sometimes paired with delivery of cytotoxic drugs like paclitaxel to reduce neointimal tissue formation. We pursue intravascular drug delivery strategies that target the underlying cause of restenosis - intimal hyperplasia resulting from stress-induced vascular smooth muscle cell switching from the healthy contractile into a pathological synthetic phenotype. We have established MAPKAP kinase 2 (MK2) as a driver of this phenotype switch and seek to establish convective and contact transfer (coated balloon) methods for MK2 inhibitory peptide delivery to sites of angioplasty. Using a flow loop bioreactor, we showed MK2 inhibition in ex vivo arteries suppresses smooth muscle cell phenotype switching while preserving vessel contractility. A rat carotid artery balloon injury model demonstrated inhibition of intimal hyperplasia following MK2i coated balloon treatment in vivo. These studies establish both convective and drug coated balloon strategies as promising approaches for intravascular delivery of MK2 inhibitory formulations to improve efficacy of balloon angioplasty.

Altered smooth muscle cell phenotypic switching in atherogenesis and -progression in a murine model of chemically induced colitis

Altered smooth muscle cell phenotypic switching in atherogenesis and -progression in a murine model of chemically induced colitis

ChemR23 expression protects against smooth muscle cell phenotype switching in atherosclerosis

ChemR23 expression protects against smooth muscle cell phenotype switching in atherosclerosis