Vascular Smooth Muscle Cell Proliferation Research Articles

Yohimbine Inhibits PDGF-Induced Vascular Smooth Muscle Cell Proliferation and Migration via FOXO3a Factor.

Yohimbine (YHB) has been reported to possess anti-inflammatory, anticancer, and cardiac function-enhancing properties. Additionally, it has been reported to inhibit the proliferation, migration, and neointimal formation of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor (PDGF) stimulation by suppressing the phospholipase C-gamma 1 pathway. However, the transcriptional regulatory mechanism of YHB controlling the behavior of VSMCs is not fully understood. In this study, YHB downregulated the expression of cell cycle regulatory proteins, such as proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin-dependent kinase 4 (CDK4), and cyclin E, by modulating the transcription factor FOXO3a in VSMCs induced by PDGF. Furthermore, YHB decreased p-38 and mTOR phosphorylation in a dose-dependent manner. Notably, YHB significantly reduced the phosphorylation at Y397 and Y925 sites of focal adhesion kinase (FAK), and this effect was greater at the Y925 site than Y397. In addition, the expression of paxillin, a FAK-associated protein known to bind to the Y925 site of FAK, was significantly reduced by YHB treatment in a dose-dependent manner. A pronounced reduction in the migration and proliferation of VSMCs was observed following co-treatment of YHB with mTOR or p38 inhibitors. In conclusion, this study shows that YHB inhibits the PDGF-induced proliferation and migration of VSMCs by regulating the transcription factor FOXO3a and the mTOR/p38/FAK signaling pathway. Therefore, YHB may be a potential therapeutic candidate for preventing and treating cardiovascular diseases such as atherosclerosis and vascular restenosis.

Fe3O4 coated stent prevent artery neointimal hyperplasia by inhibiting vascular smooth muscle cell proliferation

In-stent restenosis (ISR), caused by aggressive vascular smooth muscle cell (VSMC) proliferation, is a serious complication of stenting. Therefore, developing therapeutic approaches that target VSMC inhibition is imperative. Our previous study showed that VSMC hyperplasia was attenuated after iron stent degradation, and VSMC proliferation around the stented section was arrested. The corrosion products of the iron stents were primarily Fe3O4 particles. Therefore, we hypothesized that Fe3O4 particles generated by iron stents would prevent neointimal hyperplasia by inhibiting VSMC proliferation. To test this hypothesis, culture assays and flow cytometry were performed to investigate the proliferation of VSMC. Global gene sequencing and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to investigate the underlying mechanisms. Fe3O4-coated stents were implanted into rabbit carotid arteries to evaluate the inhibitory effects of Fe3O4 on neointimal hyperplasia. The major findings of the study were as follows: 1) Fe3O4 attenuated neointimal hyperplasia by preventing VSMC proliferation after stenting; 2) Fe3O4 exerted inhibitory effects on VSMCs by downregulating proliferative genes such as SOX9, EGR4, and TGFB1, but upregulated inhibitory genes such as DNMT1, TIMP3, and PCNA; 3) Fe3O4 inhibited VSMCs by preventing phenotypic transformation from the contractile to the synthetic phase; and 4) Fe3O4-coated stents achieved satisfactory hemocompatibility in a rabbit model. Our study highlights the additional benefits of Fe3O4 particles in inhibiting VSMC proliferation, indicating that Fe3O4 coated stent potentially served as an attractive therapeutic approach for ISR prevention.

MiR-140-3p Normalizes Vascular Smooth Muscle Cell Behavior by Inhibiting the RhoA/ROCK Signaling Pathway in Lower-extremity Arteriosclerosis Obliterans.

Excessive vascular smooth muscle cell (VSMC) proliferation and migration are the main contributors to the symptoms of lower-extremity arteriosclerosis obliterans (ASO). Previous studies suggested that microRNAs (miRNAs) regulate VSMC activity. Nevertheless, the molecular mechanisms by which they do so are unclear. The present study aimed to identify the biological processes accounting for the effects of miR-140-3p on VSMCs in ASO. The expression levels of miR-140-3p in clinical samples were analyzed by real-time polymerase chain reaction. An ASO cell model was established to investigate the expression of miR-140-3p on VSMCs. The transwell® assays and MTT assays were used to assess migration and proliferation. The interaction between RhoA and miR-140-3p was verified using the Dualluciferase reporter assay. Western blot technique was used to identify RhoA, RhoA-associated protein kinase 1 (ROCK1), and ROCK2. We discovered that miR-140-3p inhibited the proliferation, migration, and invasion but promoted the apoptosis of VSMCs, and RhoA was its downstream target gene. RhoA, ROCK1, and ROCK2 were upregulated in vascular tissues damaged by ASO compared to normal, healthy arteries. MiR-140-3p also decreased RhoA, ROCK1, and ROCK2 mRNA and protein expression. Overall, the present work partially elucidated the mechanism by which miR-140-3p regulates VSMC function and offered novel insights into potential therapeutic approaches for patients with lower-extremity arteriosclerosis obliterans.

Inhibition of CIRBP represses the proliferation and migration of vascular smooth muscle cells via inhibiting Rheb/mTORC1 axis

The excessive migration and proliferation of vascular smooth muscle cells (VSMCs) plays a vital role in vascular intimal hyperplasia. CIRBP is involved in the proliferation of various cancer cells. This study was aimed to explore the role of CIRBP in the proliferation and migration of VSMCs. Adenovirus was used to interfere with cold-inducible RNA-binding protein (CIRBP) expression, while lentivirus was used to overexpress Ras homolog enriched in brain (Rheb). Western blotting and qRT-PCR were used to evaluate the expression of CIRBP, Rheb, and mechanistic target of rapamycin complex 1 (mTORC1) activity. The cell proliferation was determined by Ki67 immunofluorescence staining and CCK-8 assay. The wound healing assay was performed to assess cell migration. Additionally, immunohistochemistry was conducted to explore the role of CIRBP in intimal hyperplasia after vascular injury. We found that silencing CIRBP inhibited the proliferation and migration of VSMCs, decreased the expression of Rheb and mTORC1 activity. Restoration of mTORC1 activity via insulin or overexpression of Rheb via lentiviral transfection both attenuated the inhibitory effects of silencing CIRBP on the proliferation and migration of VSMCs. Moreover, Rheb overexpression abolished the inhibitory effect of silencing CIRBP on mTORC1 activity in VSMCs. CIRBP was upregulated in the injured carotid artery. Silencing CIRBP ameliorated intimal hyperplasia after vascular injury. In the summary, silencing CIRBP attenuates mTORC1 activity via reducing Rheb expression, thereby supressing the proliferation and migration of VSMCs and intimal hyperplasia after vascular injury.

Genetic influence on vascular smooth muscle cell apoptosis

Vascular smooth muscle cell (VSMC) proliferation, migration, and apoptosis play important roles in many physiological processes and pathological conditions. To identify genetic influences on VSMC behavior, we measured these traits and undertook genome-wide association studies in primary umbilical artery-derived VSMCs from >2000 individuals. Although there were no genome-wide significant associations for VSMC proliferation or migration, genetic variants at two genomic loci (7p15.3 and 7q32.3) showed highly significant associations with VSMC apoptosis (P = 1.95 × 10−13 and P = 7.47 × 10−9, respectively). The lead variant at the 7p51.3 locus was associated with increased expression of the GSDME and PALS2 genes in VSMCs. Knockdown of GSDME or PALS2 in VSMCs attenuated apoptotic cell death. A protein co-immunoprecipitation assay indicated that GSDME complexed with PALS2. PALS2 knockdown attenuated activated caspase-3 and GSDME fragmentation, whilst GSDME knockdown also reduced activated caspase-3. These findings provide new insights into the genetic regulation of VSMC apoptosis, with potential utility for therapeutic development.

NOTCH3 and Pulmonary Arterial Hypertension.

NOTCH3 receptor signaling has been linked to the regulation of smooth muscle cell proliferation and the maintenance of smooth muscle cells in an undifferentiated state. Pulmonary arterial hypertension (World Health Organization Group 1 idiopathic disease: PAH) is a fatal disease characterized clinically by elevated pulmonary vascular resistance caused by extensive vascular smooth muscle cell proliferation, perivascular inflammation, and asymmetric neointimal hyperplasia in precapillary pulmonary arteries. In this review, a detailed overview of the specific role of NOTCH3 signaling in PAH, including its mechanisms of activation by a select ligand, downstream signaling effectors, and physiologic effects within the pulmonary vascular tree, is provided. Animal models showing the importance of the NOTCH3 pathway in clinical PAH will be discussed. New drugs and biologics that inhibit NOTCH3 signaling and reverse this deadly disease are highlighted.

The interplay of hydrogen sulfide and microRNAs in cardiovascular diseases: insights and future perspectives.

Hydrogen sulfide (H2S) is recognized as the third gasotransmitter, after nitric oxide (NO) and carbon monoxide (CO). It is known for its cardioprotective properties, including the relaxation of blood vessels, promotion of angiogenesis, regulation of myocardial cell apoptosis, inhibition of vascular smooth muscle cell proliferation, and reduction of inflammation. Additionally, abnormal H2S generation has been linked to the development of cardiovascular diseases (CVD), such as pulmonary hypertension, hypertension, atherosclerosis, vascular calcification, and myocardial injury. MicroRNAs (miRNAs) are non-coding, conserved, and versatile molecules that primarily influence gene expression by repressing translation and have emerged as biomarkers for CVD diagnosis. Studies have demonstrated that H2S can ameliorate cardiac dysfunction by regulating specific miRNAs, and certain miRNAs can also regulate H2S synthesis. The crosstalk between miRNAs and H2S offers a novel perspective for investigating the pathophysiology, prevention, and treatment of CVD. The present analysis outlines the interactions between H2S and miRNAs and their influence on CVD, providing insights into their future potential and advancement.

Network-based prioritization and validation of regulators of vascular smooth muscle cell proliferation in disease

Aberrant vascular smooth muscle cell (VSMC) homeostasis and proliferation characterize vascular diseases causing heart attack and stroke. Here we elucidate molecular determinants governing VSMC proliferation by reconstructing gene regulatory networks from single-cell transcriptomics and epigenetic profiling. We detect widespread activation of enhancers at disease-relevant loci in proliferation-predisposed VSMCs. We compared gene regulatory network rewiring between injury-responsive and nonresponsive VSMCs, which suggested shared transcription factors but differing target loci between VSMC states. Through in silico perturbation analysis, we identified and prioritized previously unrecognized regulators of proliferation, including RUNX1 and TIMP1. Moreover, we showed that the pioneer transcription factor RUNX1 increased VSMC responsiveness and that TIMP1 feeds back to promote VSMC proliferation through CD74-mediated STAT3 signaling. Both RUNX1 and the TIMP1–CD74 axis were expressed in human VSMCs, showing low levels in normal arteries and increased expression in disease, suggesting clinical relevance and potential as vascular disease targets.

Role of miRNAs regulation of Orai1 and store operated Ca2+ entry in vascular restenosis

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Agencia Estatal de Investigación Background The main cause of restenosis is attributed to the excessive proliferation and migration of vascular smooth muscle cells (VSMCs). Orai1 is one of the main molecular components of Store-Operated Calcium Entry (SOCE), playing a key role in VSMCs proliferation during neointima formation and vascular remodeling. Recent studies have demonstrated the implication of microRNAs (miRNAs) in VSMCs proliferation and migration, however, the role of these miRNAs as regulators of SOCE during vascular remodeling has not been described. Purpose This study aims to determine whether miRNAs regulate the intracellular Ca2+ handling, focusing on SOCE, during neointima formation. Methods Experiments were conducted in an animal rat model following the "Principles of laboratory animal care" and according to the Spanish law. The neointima development was assessed after balloon injury of carotid arteries and confirmed by haematoxylin and eosin staining, and αSMA staining of tissue sections up to 3 weeks after surgery. miRNAs array and RT-qPCR was used to examine the expression of miRNAs. Dual-Luciferase reporter assay was performed in A7R5 VSMCs line. Results Injured arteries showed significant increase in the expression of Orai1, as compared to non-injured arteries, indicating their possible participation in the neointima layer formation. Microarray of miRNAs analysis of the injured carotids compared to control carotids showed significant increase in the expression of miRNAs related to signalling pathways involving cell proliferation and migration, cell differentiation, or VSMCs contraction. Of these, we confirmed the significant increase of miR-18a-5p, miR-20a-5p, miR-20b-5p and miR-17-5p, which belong to widely studied miR-17-92 cluster involved in different cell proliferation. Moreover, we found that mimics of those miRNAs were able to regulate differentially the activity of the Orai1 promotor in A7R5 cell line, indicating that Orai1 can be targeted by miRNAs during in VSMCs. Conclusions In conclusion, our data confirms that Orai1 is upregulated during neointima formation associated with miRNAs dysregulation. Moreover, we found that Orai1-dependent SOCE can be finely regulated by miRNAs during restenosis.

C/EBPβ-Lin28a positive feedback loop triggered by C/EBPβ hypomethylation enhances the proliferation and migration of vascular smooth muscle cells in restenosis.

The main cause of restenosis after percutaneous transluminal angioplasty (PTA) is the excessive proliferation and migration of vascular smooth muscle cells (VSMCs). Lin28a has been reported to play critical regulatory roles in this process. However, whether CCAAT/enhancer-binding proteins β (C/EBPβ) binds to the Lin28a promoter and drives the progression of restenosis has not been clarified. Therefore, in the present study, we aim to clarify the role of C/EBPβ-Lin28a axis in restenosis. Restenosis and atherosclerosis rat models of type 2 diabetes (n = 20, for each group) were established by subjecting to PTA. Subsequently, the difference in DNA methylation status and expression of C/EBPβ between the two groups were assessed. EdU, Transwell, and rescue assays were performed to assess the effect of C/EBPβ on the proliferation and migration of VSMCs. DNA methylation status was further assessed using Methyltarget sequencing. The interaction between Lin28a and ten-eleven translocation 1 (TET1) was analysed using co-immunoprecipitation (Co-IP) assay. Student's t-test and one-way analysis of variance were used for statistical analysis. C/EBPβ expression was upregulated and accompanied by hypomethylation of its promoter in restenosis when compared with atherosclerosis. In vitroC/EBPβ overexpression facilitated the proliferation and migration of VSMCs and was associated with increased Lin28a expression. Conversely, C/EBPβ knockdown resulted in the opposite effects. Chromatin immunoprecipitation assays further demonstrated that C/EBPβ could directly bind to Lin28a promoter. Increased C/EBPβ expression and enhanced proliferation and migration of VSMCs were observed after decitabine treatment. Further, mechanical stretch promoted C/EBPβ and Lin28a expression accompanied by C/EBPβ hypomethylation. Additionally, Lin28a overexpression reduced C/EBPβ methylation via recruiting TET1 and enhanced C/EBPβ-mediated proliferation and migration of VSMCs. The opposite was noted in Lin28a knockdown cells. Our findings suggest that the C/EBPβ-Lin28a axis is a driver of restenosis progression, and presents a promising therapeutic target for restenosis.

Asprosin promotes vascular inflammation via TLR4-NFκB-mediated NLRP3 inflammasome activation in hypertension

Objectiveand design Mild vascular inflammation promotes the pathogenesis of hypertension. Asprosin, a newly discovered adipokine, is closely associated with metabolic diseases. We hypothesized that asprosin might led to vascular inflammation in hypertension via NLRP3 inflammasome formation. This study shows the importance of asprosin in the vascular inflammation of hypertension. MethodsPrimary vascular smooth muscle cells (VSMCs) were obtained from the aorta of animals, including spontaneously hypertensive rats (SHR), Wistar–Kyoto rats (WKY), NLRP3−/− and wild-type mice. Studies were performed in VSMCs in vitro, as well as WKY and SHR in vivo. ResultsAsprosin expressions were up-regulated in VSMCs and media of arteries in SHR. Asprosin overexpression promoted NLRP3 inflammasome activation via Toll-like receptor 4 (TLR4), accompanied with activation of NFκB signaling pathway in VSMCs. Exogenous asprosin protein showed similar roles in promoting NLRP3 inflammasome activation. Knockdown of asprosin restrained NLRP3 inflammasome and p65-NFκB activation in VSMCs of SHR. NLRP3 inhibitor MCC950 or NFκB inhibitor BAY11-7082 attenuated asprosin-caused VSMC proliferation and migration. Asprosin-induced interleukin-1β production, proliferation and migration were attenuated in NLRP3−/− VSMCs. Local asprosin knockdown in common carotid artery of SHR attenuated inflammation and vascular remodeling. ConclusionsAsprosin promoted NLRP3 inflammasome activation in VSMCs by TLR4-NFκB pathway, and thereby stimulates VSMCs proliferation, migration, and vascular remodeling of SHR.

A novel protein encoded by circLARP1B promotes the proliferation and migration of vascular smooth muscle cells by suppressing cAMP signaling

Background and aimsCircular RNA (circRNA) is closely related to atherosclerosis (AS) incidence and progression, but its regulatory mechanism in AS needs further elucidation. AS development is significantly influenced by abnormal vascular smooth muscle cells (VSMCs) growth and migration. This study explored the potential protein role of circLARP1B in VSMC proliferation and migration. MethodsWe performed whole-transcriptome sequencing in human normal arterial intima and advanced atherosclerotic plaques to screen for differentially expressed circRNAs. The sequencing results were combined with database analysis to screen for circRNAs with coding ability. Real-time quantitative polymerase chain reaction was utilized to assess circLARP1B expression levels in atherosclerotic plaque tissues and cells. circLARP1B-243aa function and pathway in VSMCs growth and migration were studied by scratch, transwell, 5-ethynyl-2′-deoxyuridine, cell counting kit-8, and Western blot experiments. ResultsWe found that circLARP1B was downregulated in atherosclerotic plaque tissue and promoted the proliferation and migration of VSMCs. circLARP1B encodes a novel protein with a length of 243 amino acids. Through functional experiments, we confirmed the role of circLARP1B-243aa in enhancing VSMCs migration and proliferation. Mechanistically, circLARP1B-243aa promotes VSMCs migration and growth by upregulating phosphodiesterase 4C to inhibit the cyclic adenosine monophosphate signaling pathway. ConclusionsOur results suggested that circLARP1B could promote VSMCs growth and migration through the encoded protein circLARP1B-243aa. Therefore, it could be a treatment target and biomarker for AS.

Concentration-Dependent Effects of Boric Acid on Osteogenic Differentiation of Vascular Smooth Muscle Cells.

Vascular calcification can be triggered by oxidative stress and inflammation. Although boron possesses antioxidant and anti-inflammatory properties, its effect on osteogenic differentiation of vascular smooth muscle cells (VSMCs) has yet to be examined. Therefore, we aimed to investigate the effect of boric acid (BA), the main form of boron in body fluids, on the osteogenic differentiation of VSMCs. Following the isolation of VSMCs, the effects of BA on cell proliferation were determined by MTT. The impact of various BA concentrations on the osteogenic differentiation of VSMCs was evaluated by Alizarin red S and alkaline phosphatase (ALP) stainings and the o-cresolphthalein complexone method. In addition, mRNA expressions of osteogenic-related (Runx2 and ALP) and antioxidant system-related genes (Nrf2 and Nqo1) were detected using qRT-PCR analysis. BA treatments did not alter the proliferation of VSMCs. Osteogenic differentiation of VSMCs treated with 100 and 500μM BA (moderate and high plasma concentrations) was no different from untreated cells. However, increased osteogenic differentiation was observed with the lowest blood level (2μM) and extremely high BA concentration (1000μM). Consistent with these results, mRNA expression of Runx2 increased with 2 and 1000μM BA treatments, while Nrf2 and Nqo1 expressions increased significantly with 100 and 500μM BA. BA has different effects on VSMCs at various concentrations. The low blood level and too high BA concentration appear detrimental as they increase the osteogenic differentiation of VSMCs in vitro. We propose to investigate BA's effects and mechanism of action on vascular calcification in vivo.

Abstract 1157: Inhibition Of P90rsk Ameliorates Pdgf-bb-induced Vascular Smooth Muscle Cell Phenotypic Change And Neointimal Hyperplasia

Platelet-derived growth factor type BB (PDGF-BB) has been reported to induce vascular smooth muscle cell (VSMC) proliferation and migration, which are major events that are highly linked to vascular diseases such as atherosclerosis and restenosis. Although p90RSK has been shown to regulate multiple cellular processes including cell growth, proliferation, survival and motility through various downstream substrates in different cell types, the role of p90RSK on PDGF-BB-induced VSMC proliferation and migration, and vascular neointima formation remains unknown. In this study, we determine whether inhibition of p90RSK protects from PDGF-BB-induced cellular phenotypic change and investigate the molecular mechanisms underlying the effect of p90RSK inhibition. In cultured primary rat VSMCs, we found that pretreatment with FMK or BI-D1870, specific inhibitors of p90RSK, suppressed PDGF-BB-induced VSMC phenotypic alteration, ECM accumulation, proliferation, and migration. In addition, FMK and BI-D1870 repressed cell cycle regulatory genes cyclin D1 and Cdk4 induced by PDGF-BB, whereas inhibition of p90RSK augmented cyclin-dependent kinase inhibitor p27 downregulated by PDGF-BB in VSMCs, suggesting that p90RSK induces VSMC proliferation via cell cycle regulation of G0/G1 phase. Notably, using the mouse model of partial carotid ligation model, FMK was found to attenuate the neointimal hyperplasia of carotid arteries. These results suggest that p90RSK impedes PDGF-BB induced VSMC phenotypic switching, proliferation, migration, and neointima formation.

Abstract 1046: Miro1 Promotes Mitochondria ER Contact Sites Formation In Vascular Smooth Muscle Cells During G1/s

Vascular smooth muscle cell (VSMC) proliferation plays a key role in vascular disorders including atherosclerosis. Mitochondria promote VSMC proliferation by mitochondrial Ca 2+ regulation, ROS and ATP production. Mitochondria-ER contact sites (MERCS) promote signal transduction to mitochondria. MIRO1, an outer mitochondrial membrane GTPase, drives intracellular mitochondrial mobility. In drosophila, MIRO1 controls MERCS formation. However, it is unknown whether this interaction promotes key cellular eukaryotic phenotypes, such as proliferation. Here, we tested whether MIRO1 promotes VSMC proliferation by modulating MERCS and mitochondrial Ca 2+ entry. MIRO1 deletion decreased neointima formation in vivo, and abolished VSMC proliferation and G1/S transition in vitro. In WT VSMCs, proximity ligation assays (PLA) and split-GFP imaging revealed that MERCS formation increased in G1/S phase along with recruitment of MIRO1. MIRO1 deletion abolished cell cycle-dependent regulation of MERCS while increasing the expression of MERCS proteins GRP75 and IP3R. MIRO1 deletion also blocked increases in baseline mitochondrial [Ca 2+ ] by mitoPericam imaging and decreases in ER [Ca 2+ ] by CEPIA-ER in G1/S phase. Additionally, the mitochondrial membrane potential (TMRM) and mitochondrial respiration significantly increased at G1/S in WT VSMCs but not in MIRO1-/- cells. In WT VSMCs, pyruvate dehydrogenase activity increased G1/S phase while cytosolic ATP levels (ATP sensor) were increased. In MIRO1-/- cells, both parameters did not change. These data demonstrate that MERCS formation and mitochondrial [Ca 2+ ] increases during the cell cycle and is controlled by MIRO1. Furthermore, MIRO1 deletion decreases cellular ATP levels in VSMCs. In conclusion, we propose that MIRO1 controls MERCS and increased mitochondrial [Ca 2+ ] that drives metabolic activity and proliferation.

Abstract 131: Local Pcsk6 Inhibition Attenuates VSMC Response In Vascular Injury And Restenosis

Intro: Vascular smooth muscle cell (VSMC) proliferation following endovascular interventions leads to restenosis, treated with drug-eluting stents. However, current drugs completely abolish vascular healing, cause thrombosis and clinical events. PCSK6 is a key protease in vascular remodeling and VSMCs activation upon vessel injury, via regulation of MMP2/14 activity. Here, we investigate whether local PCSK6 inhibition reduces VSMC proliferation and intimal hyperplasia. Methods: PCSK6 peptide inhibitor was tested in vitro on VSMCs migration, proliferation, apoptosis in comparison to rapamycin and paclitaxel. Internalization of a FITC labelled inhibitor was studied by flow cytometry and immunofluorescence. In vivo , PCSK6 inhibitor was administered at 3mg/kg IP using cationic microbubbles, followed by ultrasound-mediated local delivery in mice developing intimal hyperplasia after carotid ligation (n=8 vs 11). Carotid ligation in Tagln Cre+ /Pcsk6 fl/fl mice investigated the effect of PCSK6 specific ablation in VSMCs on intimal hyperplasia (n=7 vs 9). Carotids were collected from these and constitutive Pcsk6 -/- mice vs. controls for transcriptomic and histological analyses. Results: In vitro , PCSK6 inhibitor was internalized and inhibited both VSMC migration and proliferation (p<0.0001), reducing the expression of PCSK6, MMP2 and GDF15 . In comparison, paclitaxel showed severe VSMC toxicity, whereas rapamycin inhibited more strongly VSMC migration and proliferation than the PCSK6 inhibitor. In vivo, the inhibitor reduced intimal hyperplasia (p=0.026), again, by repressing PCSK6 and MMP2 expression in treated vs. control mice, with a favorable safety profile. Likewise, conditional VSMC Pcsk6 knockouts showed less intimal hyperplasia (p=0.053). In carotids from Pcsk6 -/- mice, cytoskeletal (Synm) and peptidase (Pgpep1l, Klk1) genes were strongly downregulated, showing its importance for vascular matrix composition. Conclusion: Our proof-of-concept translational study shows that local application of a PCSK6 inhibitor is a viable method for specifically modulating VSMC activation in intimal hyperplasia following vascular injury

Linarin Ameliorates Restenosis After Vascular Injury in Type 2 Diabetes Mellitus via Regulating ADAM10-Mediated Notch Signaling Pathway.

Vascular lesions frequently arise as complication in patients diagnosed with diabetes mellitus (DM). Presently, percutaneous coronary intervention (PCI) and antithrombotic therapy serve as primary treatments. However, in-stent restenosis persists as a challenging clinical issue following PCI, lacking sustained and effective treatment. Linarin (LN) exhibits diverse pharmacological activities and is regarded as a potential drug for treating various diseases, including DM. But its specific role in restenosis after vascular injury in DM patients remains unclear. A rat model of diabetes-related restenosis was established to evaluate the role of LN on neointimal hyperplasia. Vascular smooth muscle cells (VSMCs) stimulated by high glucose (HG, 30mM) underwent LN treatment. Additionally, an overexpression plasmid of A disintegrin and metalloproteinases (ADAM10) was constructed to transfect VSMCs. We employed CCK-8, Brdu, wound-healing scratch, and transwell migration assays to evaluate the proliferation and migration of VSMCs. Furthermore, western blot and immunofluorescence assays were utilized to investigate the expressions of ADAM10 and the downstream Notch signaling pathway in vivo and in vitro models. LN notably alleviated intimal hyperplasia after vascular injury in DM rats and reduced the protein expression of ADAM10, alongside its downstream Notch1 signaling pathway-related proteins (Notch1, NICD and Hes1) in rat carotid artery tissues. LN effectively suppressed the proliferation and migration of VSMCs induced by HG, downregulating the protein expression of ADAM10, Notch1, NICD and Hes1. Moreover, our findings indicated that ADAM10 overexpression significantly reversed LN's effects on proliferation, migration, and the expression of Notch1 signaling pathway-related proteins in HG-treated VSMCs. LN demonstrates potential therapeutic efficacy in addressing restenosis after diabetic-related vascular injury, with the ADAM10 mediated Notch signaling pathway playing a pivotal role.

Abstract 3057: Vascular Smooth Muscle Cell Cd47 Contributes To Atherosclerosis Development

Aims: Thrombospondin-1 (TSP1), a secretory protein, has been associated with various cardiovascular diseases. TSP1 mainly functions via its cognate receptors CD47 and CD36. Recently, we observed elevated TSP1 expression in human and murine atherosclerotic arteries. However, the role of vascular smooth muscle cell (VSMC) TSP1-CD47 signaling in regulating VSMC phenotype and atherogenesis is unclear. Methods and Results: Human arterial SMCs were treated with human TSP1 and analyzed for SMC markers and proliferation. The data revealed decreased expression of SMC markers, ACTA, CNN1, and SM22α in TSP1-exposed VSMCs compared with vehicle-treated control cells. Further, TSP1 treatment increased VSMC proliferation in vitro , suggesting TSP1 induces VSMC hyperproliferative phenotype. Additional experiments showed CD47 as the major TSP1’s receptor in VSMCs. To investigate the in vivo role of VSMC Cd47 in atherosclerosis, we generated tamoxifen-inducible SMC-specific Cd47 knockout mice ( Cd47 f/f Myh11 Cre +/– , Cd47 ΔVSMC ) by crossing female Cd47 f/f mice with male Myh11 Cre +/- mice. Male tamoxifen-injected Cd47 ΔVSMC and corn oil-administered Cd47 WT mice were given a single injection of AAV8- hPCSK9 (1х10 11 viral genomes/mouse, IP) and fed a Western diet for 12 weeks. En face oil red O (ORO) staining of whole aortas exhibited reduced atherosclerosis in Cd47 ΔVSMC mice compared with control Cd47 WT mice. Further histochemical staining performed on aortic root sections revealed attenuated neointimal lesion area, lipid accumulation and necrotic area in Cd47 ΔVSMC mice. However, there were no significant differences in weight gain, body composition (fat and lean mass), plasma total cholesterol, and fasting blood glucose between Cd47 ΔVSMC and Cd47 WT mice. Conclusions: Taken together, these findings suggest that TSP1 promotes VSMC phenotype switch and VSMC-specific Cd47 deletion in hypercholesterolemic mice suppresses atherosclerosis progression.

Abstract 1055: Atxn2 Inhibition Enhances The Contractile Phenotype Of Vascular Smooth Muscle Cells

Introduction: Phenotype switching of vascular smooth muscle cells (VSMC) between their synthetic and differentiated contractile state is a critical player in controlling the stability of atherosclerotic plaque. Hundreds of genes associated with coronary artery disease (CAD) have been identified through Genome-Wide Association Studies (GWAS). However, the involvement of most identified genes in the pathogenesis of atherosclerosis remains unknown. ATXN2 was identified as a CAD GWAS candidate gene with unclear biological role in atherosclerosis. ATXN2 regulates the endocytic internalization of the EGF receptor, which is essential in the VSMC phenotype switching. Therefore, we aimed to investigate whether ATXN2 is involved in the VSMC phenotype switching. Methods and Results: Using immunofluorescence, we demonstrated that ATXN2 siRNA knockdown resulted in a 5-fold increase in the ratio of the contractile phenotype of human aortic VSMC that expressed a high alpha-smooth muscle cell actin content compared to controls. In addition, we found that ATXN2 inhibition reduced the VSMC proliferation and migration as assessed by the EdU cell proliferation assay and the wound healing migration assay, respectively. Next, we confirmed that ATXN2 siRNA knockdown increased the mRNA expression of contractile markers: calponin, alpha-smooth muscle cell actin, and smooth muscle protein 22 alpha using quantitative PCR. We found that the enhancing effect of VSMC contractile phenotype by ATXN2 siRNA was less pronounced in the absence of TGF-beta. Indeed, the enhancing effect of ATXN2 inhibition on the VSMC contractile phenotype was abolished by SMAD4 gene silencing, suggesting the involvement of TGF-beta signaling. Furthermore, we validated the expression signature of the ATXN2 gene in different phenotypic subsets of VSMC from human atherosclerotic plaque samples using single-cell RNA sequencing analysis. We detected that ATXN2 expression was negatively correlated with the contractile VSMC subset. In conclusion, our findings suggests ATXN2, CAD GWAS candidate gene, as a novel potential therapeutic target to enhance the VSMC contractile phenotype for stabilizing atherosclerotic plaque in coronary artery disease patients.

Abstract 1129: Ddx24 In Vascular Smooth Muscle Cells Is Essential For Embryonic Vascular Development

Background: The DEAD-box family plays a crucial role in tumorigenesis and immune responses. Our previous research has identified an association between the dysfunction of DEAD-box RNA helicase 24 (DDX24) and a specific type of vascular malformation. However, the role and mechanism of DDX24 in vascular development remains unclear.Research questions: What is the role of DDX24 in regulating vascular smooth muscle cell (VSMC) function and embryonic vascular development? Aims: Our aim is to investigate the function and regulatory mechanism of DDX24 in embryonic vascular development. Methods: Cardiomyocyte/VSMC-specific Ddx24 knockout mice were generated by crossing Tagln -Cre mice with Ddx24 flox/flox transgenic mice. Stereomicroscopic photography and immunofluorescence staining were used to examine the development of blood vessels. Flow cytometry and cell proliferation assays were employed to assess the effect of DDX24 on VSMC functions. RNA sequencing and RNA immunoprecipitation were performed to uncover the downstream target of DDX24. Additionally, RNA pull-down and RNA stability experiments were conducted to elucidate the regulatory mechanism. Results: Cardiomyocyte/VSMC-specific Ddx24 knockout mice died before embryonic day 13.5 and exhibited defects in embryonic vascular formation and vascular remodeling in extraembryonic tissues. Ddx24 knockdown led to the suppression of VSMC proliferation through cell cycle arrest, likely due to increased DNA damage. DDX24 protein was found to bind to and stabilize the mRNA of FA complementation group A ( FANCA ), a gene that responds to DNA damage. Depletion of FANCA also affected cell cycle and DNA repair in VSMCs. Overexpression of FANCA successfully rescued the alterations induced by DDX24 deficiency. Conclusion: Our study illuminates the role of DDX24 in VSMC-mediated vascular development, suggesting a potential therapeutic target for diseases associated with VSMC dysfunction.