Mouse Vascular Smooth Muscle Cells Research Articles

Deletion of smooth muscle ZFP36 promotes neointimal hyperplasia in mice.

Platelet-derived growth factor (PDGF-BB) released from the injured intima induces the proliferation and migration of vascular smooth muscle cells (VSMCs), which is the key mechanism of neointimal hyperplasia. Zinc finger 36 (ZFP36), a widespread RNA-binding protein, is important for pathological processes in many diseases. In this study we investigated the role of ZFP36 in VSMCs proliferation, migration and neointimal hyperplasia in mice. We generated smooth muscle-specific Zfp36 knockout (Zfp36SMKO) mice, and established restenosis mouse models by ligation of left carotid artery in Zfp36SMKO mice. We showed that the expression levels of ZFP36 were significantly decreased in human atherosclerotic coronary arteries and murine injured carotid arteries compared with controls. Compared to control Zfp36fl/fl mice, Zfp36SMKO mice displayed accelerated neointimal hyperplasia. In cultured mouse VSMCs, PDGF-BB (20 ng/mL) significantly downregulated ZFP36 expression through KLF4 binding site in Zfp36 promoter. We revealed that ZFP36 could bind to the mRNA of cell migration-inducing protein (CEMIP) and promoted its degradation in VSMCs, thereby reducing the expression of CEMIP protein. Knockdown of Cemip inhibited VSMCs proliferation and migration induced by Zfp36 knockout, thereby suppressing neointimal hyperplasia in Zfp36SMKO mice. We conclude that vascular smooth muscle ZFP36 has a protective effect against neointimal hyperplasia by reducing CEMIP expression. ZFP36 is downregulated by vascular injury and PDGF-BB treatment, which promotes VSMCs proliferation and migration and neointima formation. The results suggest that targeting ZFP36 may represent a novel therapeutic strategy for preventing or treating neointimal hyperplasia and related cardiovascular diseases.

Role of Ciliary Neurotrophic Factor in Angiotensin II-Induced Hypertension.

Ciliary neurotrophic factor (CNTF), mainly known for its neuroprotective properties, belongs to the IL-6 (interleukin-6) cytokine family. In contrast to IL-6, the effects of CNTF on the vasculature have not been explored. Here, we examined the role of CNTF in AngII (angiotensin II)-induced hypertension. Hypertension was chronically induced with AngII (1000 ng/kg per minute, osmotic mini-pumps, 14 days) in CNTF-knockout and wild-type mice (with or without nephrectomy and 1% NaCl drinking water). Blood pressure was measured by tail-cuff and radiotelemetry. Effects of CNTF on vascular function and the JAK2/STAT3 pathway were measured in vivo, in the isolated perfused kidney, and in mouse and human vascular smooth muscle cells. At baseline, systolic blood pressure was similar between both groups. During AngII infusion, blood pressure increase was significantly attenuated and hypertensive heart and kidney damage was significantly attenuated in CNTF-knockout compared with wild-type mice. Accordingly, renal pressor response to AngII but not KCl or phenylephrine was significantly decreased in CNTF-knockout compared with wild-type mice. Acute CNTF (5 µmol/L) administration nearly restored the AngII-dependent renal pressor response. Chronic CNTF treatment in CNTF-knockout mice increased blood pressure response to AngII to levels observed in wild-type mice. CNTF augments AngII-induced activation of the JAK2/STAT3 pathway in vitro in vascular smooth muscle cells. The significance of this interaction was shown, as the increase in renal pressor response by CNTF was abolished by JAK2/STAT3 inhibitors. Our results demonstrate a major impact of CNTF on blood pressure regulation by modulating AngII-induced pressor response via a JAK2/STAT3-dependent mechanism and indicate that CNTF is an important regulatory cytokine in hypertension.

Magnolia kobus DC. Regulates Vascular Smooth Muscle Cell Proliferation by Modulating O-GlcNAc and MOF Expression.

Vascular smooth muscle cells (VSMCs) undergo metabolic pathway transitions, including aerobic glycolysis, fatty acid oxidation, and amino acid metabolism, which are important for their function. Metabolic dysfunction in VSMCs can lead to age-related vascular diseases. O-GlcNAcylation, a nutrient-dependent posttranslational modification linked specifically to glucose metabolism, plays an important role in this context. Magnolia kobus DC. (MK), derived from the flower buds of Magnolia biondii, is known for its anticancer, anti-allergy, and anti-inflammatory properties. However, the role of O-GlcNAcylation in VSMCs under aging and the association between MK and O-GlcNAc remain unclear. Therefore, the present study aimed to determine the effects of O-GlcNAc on VSMC proliferation, along with the expression of MOF (males absent on the first, KAT8) and its correlation with the efficacy of MK. The results showed that aging and O-GlcNAc induction increased the expression levels of O-GlcNAc, O-GlcNAc transferase (OGT), ataxia telangiectasia mutated (ATM) protein, and MOF in mouse vascular smooth muscle cells (MOVAS) and aorta tissue. Transfection with OGT siRNA reduced the expression of MOF and OGT, indicating that OGT regulates MOF and influences cell proliferation. MK treatment reduced the expression of OGT, ATM, and MOF, which was correlated with O-GlcNAc levels. These findings suggest that O-GlcNAcylation is important for VSMC homeostasis and may be a novel target for vascular diseases. Thus, MK exhibits potential as a new drug candidate for treating vascular diseases by modulating O-GlcNAcylation and MOF interactions.

Survivin modulates stiffness-induced vascular smooth muscle cell motility.

Arterial stiffness is a key contributor to cardiovascular diseases, including atherosclerosis, restenosis, and coronary artery disease, it has been characterized to be associated with the aberrant migration of vascular smooth muscle cells (VSMCs). However, the underlying molecular mechanisms driving VSMC migration in stiff environments remain incompletely understood. We recently demonstrated that survivin, a member of the inhibitor of apoptosis protein family, is highly expressed in both mouse and human VSMCs cultured on stiff polyacrylamide hydrogels, where it modulates stiffness-mediated cell cycle progression and proliferation. However, its role in stiffness-dependent VSMC migration remains unknown. To assess its impact on migration, we performed time-lapse video microscopy on VSMCs seeded on fibronectin-coated soft and stiff polyacrylamide hydrogels, mimicking the physiological stiffness of normal and diseased arteries, with either survivin inhibition or overexpression. We observed that VSMC motility increased under stiff conditions, while pharmacologic or siRNA-mediated inhibition of survivin reduced stiffness-stimulated migration to rates similar to those observed under soft conditions. Further investigation revealed that cells on stiff hydrogels exhibited greater directional movement and robust lamellipodial protrusion compared to those on soft hydrogels. Interestingly, survivin-inhibited cells on stiff hydrogels showed reduced directional persistence and lamellipodial protrusion compared to control cells. We also examined whether survivin overexpression alone is sufficient to induce cell migration on soft hydrogels, and found that survivin overexpression modestly increased cell motility and partially rescued the lack of directional persistence compared to GFP-expressing control VSMCs on soft hydrogels. In conclusion, our findings demonstrate that survivin plays a key role in regulating stiffness-induced VSMC migration, suggesting that targeting survivin and its signaling pathways could offer therapeutic strategies for addressing arterial stiffness in cardiovascular diseases.

Aldosterone promotes calcification of vascular smooth muscle cells in mice through the AIF-1/Wnt/β-catenin signaling pathway.

This study aimed to investigate the impact of aldosterone on calcification in murine vascular smooth muscle cells (VSMCs) via the allograft inflammatory factor-1 (AIF-1)/Wnt/β-catenin signaling pathway. Mouse VSMCs were cultured in vitro, and calcification was induced by treatment with 100nM aldosterone. The level of calcification in mouse VSMCs was evaluated using colorimetric assays to assess ALP activity and qRT-PCR to identify the expression of calcification-related markers, such as Runx2, α-SMA, OCN, and ALP mRNA. Western blot analysis was performed to determine the protein expression levels associated with the Wnt/β-catenin pathway (LRP6, p-LRP6, GSK3β, p-GSK3β, β-catenin) and AIF-1. Plasmid transfection techniques were utilized to either knock down or overexpress AIF-1, and the subsequent alterations in these markers were observed. (1) Compared to the control group, the aldosterone treatment group with exhibited a significant increase in ALP. Concurrently, Runx2, OCN, and ALP mRNA levels increased, as did LRP6, p-LRP6, GSK3β, p-GSK3β, β-catenin, and AIF-1 protein levels. Additionally, a significant decrease in the expression of α-SMA mRNA was observed (P < 0.05). (2) The aldosterone + oe-AIF-1 group showed significant increases in ALP activity compared to the aldosterone + oe-NC group, whereas the aldosterone + sh-AIF-1 group showed significant decreases (P < 0.05). (3) The aldosterone + oe-AIF-1 group exhibited significantly upregulated expression of AIF-1, p-LRP6/LRP6, p-GSK3β/GSK3β, and β-catenin proteins relative to the aldosterone + oe-NC group (P < 0.05). This was concurrent with increased mRNA expression of Runx2, OCN, and ALP, and decreased α-SMA mRNA expression (P < 0.05). Aldosterone affects the calcification process in mouse VSMCs, and the activation of the AIF-1/Wnt/β-catenin signaling pathway is the mechanism behind its action.

GDF10 is a negative regulator of vascular calcification

Cardiovascular mortality is particularly high and increasing in patients with chronic kidney disease, with vascular calcification (VC) as a major pathophysiologic feature. VC is a highly regulated biological process similar to bone formation involving osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs). We have previously demonstrated that loss of T-cell death-associated gene 51 (TDAG51) expression leads to an attenuation of medial VC. We now show a significant induction of circulating levels of growth differentiation factor 10 (GDF10) in TDAG51-/- mice, which was of interest due to its established role as an inhibitor of osteoblast differentiation. The objective of this study was to examine the role of GDF10 in the osteogenic transdifferentiation of VSMCs. Using primary mouse and human VSMCs, as well as exvivo aortic ring cultures, we demonstrated that treatment with recombinant human (rh) GDF10 mitigated phosphate-mediated hydroxyapatite (HA) mineral deposition. Furthermore, exvivo aortic rings from GDF10-/- mice exhibited increased HA deposition compared to C57BL/6J controls. To explain our observations, we identified that rhGDF10 treatment reduced protein expression of runt-related transcription factor 2, a key driver of osteogenic transdifferentiation of VSMCs and VC. In support of these findings, invivo treatment with rhGDF10 attenuated VD3-induced VC. Furthermore, we demonstrated an increase in circulating GDF10 in patients with chronic kidney disease with clinically defined severe VC, as assessed by coronary artery calcium score. Thus, our studies identify GDF10 as a novel inhibitor of mineral deposition and as such, may represent a potential novel biomarker and therapeutic target for the detection and management of VC.

Electrophysiology of Human iPSC-derived Vascular Smooth Muscle Cells and Cell-autonomous Consequences of Cantú Syndrome Mutations.

Cantú syndrome (CS), a multisystem disease with a complex cardiovascular phenotype, is caused by gain-of-function (GoF) variants in the Kir6.1/SUR2 subunits of ATP-sensitive potassium (KATP) channels and is characterized by low systemic vascular resistance, as well as tortuous, dilated, vessels, and decreased pulse-wave velocity. Thus, CS vascular dysfunction is multifactorial, with both hypomyotonic and hyperelastic components. To dissect whether such complexities arise cell autonomously within vascular smooth muscle cells (VSMCs) or as secondary responses to the pathophysiological milieu, we assessed electrical properties and gene expression in human induced pluripotent stem cell-derived VSMCs (hiPSC-VSMCs), differentiated from control and CS patient-derived hiPSCs, and in native mouse control and CS VSMCs. Whole-cell voltage clamp of isolated aortic and mesenteric arterial VSMCs isolated from wild-type (WT) and Kir6.1[V65M] (CS) mice revealed no clear differences in voltage-gated K+ (Kv) or Ca2+ currents. Kv and Ca2+ currents were also not different between validated hiPSC-VSMCs differentiated from control and CS patient-derived hiPSCs. While pinacidil-sensitive KATP currents in control hiPSC-VSMCs were similar to those in WT mouse VSMCs, they were considerably larger in CS hiPSC-VSMCs. Under current-clamp conditions, CS hiPSC-VSMCs were also hyperpolarized, consistent with increased basal K conductance and providing an explanation for decreased tone and decreased vascular resistance in CS. Increased compliance was observed in isolated CS mouse aortae and was associated with increased elastin mRNA expression. This was consistent with higher levels of elastin mRNA in CS hiPSC-VSMCs and suggesting that the hyperelastic component of CS vasculopathy is a cell-autonomous consequence of vascular KATP GoF. The results show that hiPSC-VSMCs reiterate expression of the same major ion currents as primary VSMCs, validating the use of these cells to study vascular disease. Results in hiPSC-VSMCs derived from CS patient cells suggest that both the hypomyotonic and hyperelastic components of CS vasculopathy are cell-autonomous phenomena driven by KATP overactivity within VSMCs .

#1299 The SGLT2 inhibitor canagliflozin, but not dapagliflozin or empagliflozin, ameliorates vascular calcification in a mouse model of nephrocalcinosis

Abstract Background and Aims Vascular calcification, defined as the abnormal deposition of minerals in blood vessels, is a major cardiovascular risk factor in patients with kidney failure. Sodium-glucose co-transporter 2 (SGLT2) inhibitors, commonly known as gliflozins, are a class of pharmaceutical compounds that have revolutionised the therapeutic management of type 2 diabetes. These drugs target the SGLT2 transporter, increasing glucose elimination through the urine, effectively lowering hyperglycaemia. In addition to their effect on blood sugar control, SGLT2 inhibitors have recently gained attention for potential cardiovascular benefits in patients with type 2 diabetes, chronic kidney disease (CKD) or established cardiovascular disease. Initially thought to be secondary to the promotion of urinary sodium and glucose excretion and weight loss, recent studies have also reported direct effects of gliflozins on the vascular compartment. Given the significant impact of vascular calcification on cardiovascular health in patients with kidney failure, the aim of this study was to investigate whether the three different SGLT2 inhibitors (canagliflozin, empagliflozin and dapagliflozin) could reduce the development of vascular calcification. Method Western blotting was used to investigate SGLT2 expression in mouse and human vascular smooth muscle cells (VSMC) and vascular explants. Human and mouse aortic VSMC and mouse aorta and human epigastric and iliac artery segments were treated with calcification medium supplemented with 1 or 5 µM of gliflozins. A nephrocalcinosis mouse model consisting of 2 weeks of high phosphorus diet (2%) in female DBA/2 mice was used in in vivo experiments. The animals were treated daily with the different gliflozins (3 mg/kg/j) by oral gavage. Calcium deposits were quantified using a quantitative colorimetric assay and alizarin red staining, blood and urine glucose levels were measured using a quantitative colorimetric assay and glomerular filtration rate (GFR) was measured using sinistrin-FITC excretion. Results We observed that SGLT2 is expressed in mouse and human vessels and vascular smooth muscle cells (VSMC). Treatment with canagliflozin, but not dapagliflozin or empagliflozin, reduced calcification in vitro, in human and mouse VSMC and ex vivo, in mouse aorta and human epigastric and iliac artery segments. The high phosphorus diet in mice led to nephrocalcinosis associated with impaired renal function as well as vascular calcification development in the aorta. In this model, although all 3 gliflozins showed efficacy in increasing urinary glucose excretion, blood glucose levels were not affected by gliflozins and renal function was not improved. However, canagliflozin, but not dapagliflozin or empagliflozin, significantly reduced vascular calcification in this nephrocalcinosis mouse model. Conclusion Our study demonstrated that canagliflozin reduces vascular calcification development, highlighting its potential as a therapeutic strategy. This protective effect was found to be drug-dependent and not class-dependent, as the other two SGLT2 inhibitors, dapagliflozin and empagliflozin, showed no significant effect on vascular calcification. Further studies are needed to understand the mechanisms and pathways involved and to determine whether the differential effect of the gliflozins is due to an off-target action of canagliflozin on other SGLT transporters.

#571 Vitamin D receptor from VSMCs regulates vascular calcification during CKD: a potential role for miR-145a

Abstract Background and Aims Vascular calcification (VC) is a highly prevalent complication of chronic kidney disease (CKD) and is associated with the higher morbidity-mortality of patients with CKD. Vitamin D receptor (VDR) has been proposed to play a role in the osteoblastic differentiation of vascular smooth muscle cells (VSMCs), but the involvement of vitamin D (1, 25D) in VC associated to CKD is controversial. Accumulating evidence points to microRNAs as important players in the process of VC and recent studies show that miR-145a expression decreases in VSMCs during VC. In addition, VDR has been considered as a potent regulator of these small molecules, while miR-145a was identified as a target for 1, 25D. Our aim was to determine the role of local vitamin D signalling in VSMCs during CKD-induced VC and the involvement of miR-145a in this process. Method We used epigastric arteries from CKD-affected patients and from individuals with normal renal function. In vivo, we employed an experimental model of CKD-induced VC in mice with conditional deletion of VDR in VSMC (Myh11-CreERT2+ VDRlox/lox), while in vitro, we used mouse VSMC with (VDRwt) or without VDR (VDRko) incubated in calcification media. Transfection experiments with mmu-miR-145a-5p mimic or mmu-miR-145a-5p inhibitor were carried out in mouse VDRwt VSMCs. Results CKD-affected patients showed an increase in VC, alongside an increased arterial expression of VDR compared with controls with normal renal function. Conditional gene silencing of VDR in arterial VSMCs led to a significant decrease of VC in the mouse model of CKD, despite similar levels of renal impairment and serum calcium and phosphate levels. This was accompanied by lower arterial expression of osteopontin (OPN) and lamin A, and a higher expression of sclerostin (SOST). Runx2 was increased in arteries of both CKD groups independently of the presence of VDR in VSMCs. Furthermore, CKD-affected mice showed a reduction of miR-145a expression in calcified arteries, which was significantly recovered in animals with deletion of VDR in VSMCs. In vitro, the absence of VDR prevented VC, inhibited the increase of OPN, and re-established the expression of miR-145a. Forced expression of miR-145a in vitro in VDRwt VSMCs blunted VC and decreased OPN levels. Mir-145a levels markedly decreased both in human and mouse VDRwt VSMCs incubated in calcification media and 1, 25D. Overexpression of miR-145a suppressed the levels of OPN induced by 1, 25D, while the inhibition of mir-145a led to a significant increase in OPN levels, even higher than in cells treated solely with 1, 25D. A predicted miR-145a-binding site was detected at the 3’UTR of OPN mRNA transcript, through the extended seed region of the miRNA, pointing to OPN as a possible target of mir-145a during VC in CKD. There were no significant differences in Runx2 levels in 1, 25D-treated cells after transfection with mir-145a mimic or inhibitor. Conclusion VDR is induced in calcified VSMCs during CKD where it can modulate the expression of promoters and inhibitors of VSMC transdifferentiation, as well as small noncoding RNA molecules such as mir-145a that modulate VC. The regulation of these pathways by VDR seems to be essential for the settings of CKD-induced VC, as deletion of VDR from VSMCs prevented it.

Abstract 1026: Apolipoprotein A1 On High-density Lipoprotein Interferes With Low-density Lipoprotein Binding To Proteoglycans

Background: The entrapment of apolipoprotein (APO) B-100 containing low density lipoproteins (LDL) by proteoglycans (PGs) in the extracellular matrix (ECM) of the arterial intima is a key initial step in the development of atherosclerotic vascular lesions. High density lipoproteins (HDL) can interfere with this process, but the underlying mechanism is not fully understood and is thought to be due to APOE. The aim of this study was to utilize our recently developed quantitative assay that measures the binding of LDL to PGs in the ECM and to investigate how HDL and other apolipoproteins may influence this process. Methods: An in-cell ELISA was used to measure the binding of LDL to PGs in the ECM synthesized by mouse vascular smooth muscle cells. Fast Protein Liquid Chromatography, immunoprecipitation, and immunoblotting analysis were performed to identify how HDL interacts with LDL to prevent binding to ECM-PGs. Results: LDL binding to PGs was inhibited by HDL and APOA1 in a dose dependent manner. Competition experiments showed that HDL does not compete directly with LDL for ECM-PG binding. Instead, our data revealed an association between LDL with APOA1 that diminishes LDL ability to bind ECM-PGs. Conclusion: HDL inhibits LDL binding to ECM-PG through an interaction with its main apolipoprotein, APOA1 that is different from APOE. Further investigation is warranted to understand the role of this interaction in the atherosclerosis process.

Corilagin relieves atherosclerosis via the toll-like receptor 4 signaling pathway in vascular smooth muscle cells.

Corilagin possesses a diverse range of pharmacologic bioactivities. However, the specific protective effects and mechanisms of action of corilagin in the context of atherosclerosis remain unclear. In this study, we investigated the impact of corilagin on the toll-like receptor (TLR)4 signaling pathway in a mouse vascular smooth muscle cell line (MOVAS) stimulated by oxidized low-density lipoprotein (ox-LDL). Additionally, we examined the effects of corilagin in Sprague-Dawley rats experiencing atherosclerosis. The cytotoxicity of corilagin was assessed using the CCK8 assay. MOVAS cells, pre-incubated with ox-LDL, underwent treatment with varying concentrations of corilagin. TLR4 expression was modulated by either downregulation through small interfering (si)RNA or upregulation via lentivirus transfection. Molecular expression within the TLR4 signaling pathway was analyzed using real-time polymerase chain reaction (PCR) and Western blotting. The proliferation capacity of MOVAS cells was determined through cell counting. In a rat model, atherosclerosis was induced in femoral arteries using an improved guidewire injury method, and TLR4 expression in plaque areas was assessed using immunofluorescence. Pathological changes were examined through hematoxylin and eosin staining, as well as Oil-Red-O staining. Corilagin demonstrated inhibitory effects on the TLR4 signaling pathway in MOVAS cells pre-stimulated with ox-LDL, consequently impeding the proliferative impact of ox-LDL. The modulation of TLR4 expression, either through downregulation or upregulation, similarly influenced the expression of downstream molecules. In an in vivo context, corilagin exhibited the ability to suppress TLR4 and MyD88 expression in the plaque lesion areas of rat femoral arteries, thereby alleviating the formation of atherosclerotic plaques. Corilagin can inhibit the TLR4 signaling pathway in VSMCs, possibly by downregulating TLR4 expression and, consequently, relieving atherosclerosis.

Extracellular Histones Promote Calcium Phosphate-Dependent Calcification in Mouse Vascular Smooth Muscle Cells.

Vascular calcification, a major risk factor for cardiovascular events, is associated with a poor prognosis in chronic kidney disease (CKD) patients. This process is often associated with the transformation of vascular smooth muscle cells (VSMCs) into cells with osteoblast-like characteristics. Damage-associated molecular patterns (DAMPs), such as extracellular histones released from damaged or dying cells, are suspected to accumulate at calcification sites. To investigate the potential involvement of DAMPs in vascular calcification, we assessed the impact of externally added histones (extracellular histones) on calcium and inorganic phosphate-induced calcification in mouse VSMCs. Our study found that extracellular histones intensified calcification. We also observed that the histones decreased the expression of VSMC marker genes, while simultaneously increasing the expression of osteoblast marker genes. Additionally, histones treated with DNase I, which degrades dsDNA, attenuated this calcification, compared with the non-treated histones, suggesting a potential involvement of dsDNA in this process. Elevated levels of dsDNA were also detected in the serum of CKD model mice, underlining its potential role in vascular calcification in CKD. Our findings suggest that extracellular histones could play a pivotal role in the vascular calcification observed in CKD.

A novel assay to measure low-density lipoproteins binding to proteoglycans.

The binding of low-density lipoprotein (LDL) to proteoglycans (PGs) in the extracellular matrix (ECM) of the arterial intima is a key initial step in the development of atherosclerosis. Although many techniques have been developed to assess this binding, most of the methods are labor-intensive and technically challenging to standardize across research laboratories. Thus, sensitive, and reproducible assay to detect LDL binding to PGs is needed to screen clinical populations for atherosclerosis risk. The aim of this study was to develop a quantitative, and reproducible assay to evaluate the affinity of LDL towards PGs and to replicate previously published results on LDL-PG binding. Immunofluorescence microscopy was performed to visualize the binding of LDL to PGs using mouse vascular smooth muscle (MOVAS) cells. An in-cell ELISA (ICE) was also developed and optimized to quantitatively measure LDL-PG binding using fixed MOVAS cells cultured in a 96-well format. We used the ICE assay to show that, despite equal APOB concentrations, LDL isolated from adults with cardiovascular disease bound to PG to a greater extent than LDL isolated from adults without cardiovascular disease (p<0.05). We have developed an LDL-PG binding assay that is capable of detecting differences in PG binding affinities despite equal APOB concentrations. Future work will focus on candidate apolipoproteins that enhance or diminish this interaction.

Ferrostatin-1 inhibits ferroptosis of vascular smooth muscle cells and alleviates abdominal aortic aneurysm formation through activating the SLC7A11/GPX4 axis.

Ferroptosis, a type of iron-catalyzed necrosis, is responsible for vascular smooth muscle cell (VSMC) death and serves as a potential therapeutic target for alleviating aortic aneurysm. Here, our study explored the underlying mechanism of ferroptosis affecting VSMC functions and the resultant formation of AAA using its inhibitor Ferrostatin-1 (Fer-1). Microarray-based gene expression profiling was employed to identify differentially expressed genes related to AAA and ferroptosis. An AAA model was established by angiotensin II (Ang II) induction in apolipoprotein E-knockout (ApoE-/- ) mice, followed by injection of Fer-1 and RSL-3 (ferroptosis inducer). Then, the role of Fer-1 and RSL-3 in the ferroptosis of VSMCs and AAA formation was analyzed in Ang II-induced mice. Primary mouse VSMCs were cultured invitro and treated with Ang II, Fer-1, sh-SLC7A11, or sh-GPX4 to assess the effect of Fer-1 via the SLC7A11/GPX axis. Bioinformatics analysis revealed that GPX4 was involved in the fibrosis formation of AAA, and there was an interaction between SLC7A11 and GPX4. Invitro assays showed that Fer-1 alleviated Ang II-induced ferroptosis of VSMCs and retard the consequent AAA formation. The mechanism was associated with activation of the SLC7A11/GPX4 pathway. Silencing of SLC7A11 or GPX4 could inhibit the ameliorating effect of Fer-1 on the ferroptosis of VSMCs. Invivo animal studies further demonstrated that Fer-1 inhibited Ang II-induced ferroptosis and vessel wall structural abnormalities in AAA mouse through activation of the SLC7A11/GPX4 pathway. Fer-1 may prevent AAA formation through activation of the SLC7A11/GPX4 pathway.

Murine double minute 2-mediated estrogen receptor 1 degradation activates macrophage migration inhibitory factor to promote vascular smooth muscle cell dedifferentiation and oxidative stress during thoracic aortic aneurysm progression

Estrogen receptor 1 (ESR1) has been recently demonstrated as a potential diagnostic biomarker for thoracic aortic aneurysm (TAA). However, its precise role in the progression of TAA remains unclear. In this study, TAA models were established in ApoE-knockout mice and primary mouse vascular smooth muscle cells (VSMCs) through treatment with angiotensin (Ang) II. Our findings revealed a downregulation of ESR1 in Ang II-induced TAA mice and VSMCs. Upregulation of ESR1 mitigated expansion and cell apoptosis in the mouse aorta, reduced pathogenetic transformation of VSMCs, and reduced inflammatory infiltration and oxidative stress both in vitro and in vivo. Furthermore, we identified macrophage migration inhibitory factor (MIF) as a biological target of ESR1. ESR1 bound to the MIF promoter to suppress its transcription. Artificial MIF restoration negated the mitigating effects of ESR1 on TAA. Additionally, we discovered that murine double minute 2 (MDM2) was highly expressed in TAA models and mediated protein degradation of ESR1 through ubiquitination modification. Silencing of MDM2 reduced VSMC dedifferentiation and suppressed oxidative stress. However, these effects were reversed upon further silencing of ESR1. In conclusion, this study demonstrates that MDM2 activates MIF by mediating ESR1 degradation, thus promoting VSMC dedifferentiation and oxidative stress during TAA progression.

γ‐Glutamylcysteine Inhibits VSMC‐Derived Foam Cell Formation via Upregulating Thioredoxin‐1 Expression

The formation and accumulation of foam cells within the arterial wall is the main early event of atherosclerosis. Vascular smooth muscle cells (VSMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute to atheroma foam cells. γ‐glutamylcysteine (γ‐GC), as an immediate precursor of glutathione, exhibits anti‐inflammatory and antioxidant effects. However, the effects of γ‐GC on the formation of atherosclerotic plaques are not yet clarified. Here, we display the effects of γ‐GC against ox‐LDL‐induced formation of foamy VSMCs. Our results showed that γ‐GC apparently reduced the total intracellular cholesterol content in mouse and rat VSMCs. The oil red O and fluorescent BODIPY staining indicated that γ‐GC inhibited the formation of foam cell. Mechanistically, γ‐GC reduced the expression of macrophage scavenger receptor 1 (Msr1) in VSMCs to attenuate cholesterol uptake by the cells. Further RNA‐seq analysis, and immunofluorescence as well as immunoblotting measurements showed that thioredoxin‐1 (Txn1) was important for γ‐GC to reduce Msr1 expression in VSMCs and lipid uptake by the cells. Overall, our research indicated that γ‐GC increases Txn1 expression, which causes scavenger receptor A reduction and lipid uptake inhibition in ox‐LDL‐stimulated VSMCs. Our study revealed that γ‐GC has potential for the prevention of atherosclerosis.

Zic family member 3 attenuates oxidative stress-induced vascular smooth muscle cell apoptosis in patients with chronic kidney disease

Neointimal hyperplasia is reportedly essential for arteriovenous fistulas (AVF) in patients undergoing hemodialysis. Oxidative stress is vital in the progression of uremic venous intimal hyperplasia. Studies have suggested that zinc ions obstruct vascular calcification in patients with chronic kidney disease (CKD). Recent studies have shown that the zinc finger protein, Zic family member 3 (ZIC3), is crucial for the earliest cardiovascular progenitors. ZIC3 mutations are associated with congenital heart disease. However, the mechanism of action of ZIC3 in vascular intimal hyperplasia in CKD remains unelucidated. Venous specimens were collected during primary AVF surgery and traumatic amputation, and serum samples were collected from patients with CKD and healthy controls. Mouse vascular smooth muscle cells (VSMCs) were treated with hydrogen peroxide (H2O2) to clarify the role of ZIC3 in CKD. ZIC3 expression was reduced in the veins of patients with uremia and the serum of those with CKD. Zic3 and Bcl2 levels were significantly decreased in mouse VSMCs treated with H2O2·H2O2 inhibited mouse VSMC activity, upregulated Bax, and cleaved caspase 3 expression. Following Zic3 overexpression, Bcl2 expression level and cell viability were elevated, whereas Bax and cleaved caspase 3 expression levels were downregulated. In contrast, Zic3 knockdown yielded the opposite results. Therefore, ZIC3 could be a new therapeutic target in venous neointimal hyperplasia of CKD.

Brazil nut treatment attenuates vascular calcification in mouse vascular smooth muscle cells

Brazil nut treatment attenuates vascular calcification in mouse vascular smooth muscle cells

Survivin as a mediator of stiffness-induced cell cycle progression and proliferation of vascular smooth muscle cells.

Stiffened arteries are a pathology of atherosclerosis, hypertension, and coronary artery disease and a key risk factor for cardiovascular disease events. The increased stiffness of arteries triggers a phenotypic switch, hypermigration, and hyperproliferation of vascular smooth muscle cells (VSMCs), leading to neointimal hyperplasia and accelerated neointima formation. However, the mechanism underlying this trigger remains unknown. Our analyses of whole-transcriptome microarray data from mouse VSMCs cultured on stiff hydrogels simulating arterial pathology identified 623 genes that were significantly and differentially expressed (360 upregulated and 263 downregulated) relative to expression in VSMCs cultured on soft hydrogels. Functional enrichment and gene network analyses revealed that these stiffness-sensitive genes are linked to cell cycle progression and proliferation. Importantly, we found that survivin, an inhibitor of apoptosis protein, mediates stiffness-dependent cell cycle progression and proliferation as determined by gene network and pathway analyses, RT-qPCR, immunoblotting, and cell proliferation assays. Furthermore, we found that inhibition of cell cycle progression did not reduce survivin expression, suggesting that survivin functions as an upstream regulator of cell cycle progression and proliferation in response to ECM stiffness. Mechanistically, we found that the stiffness signal is mechanotransduced via the FAK-E2F1 signaling axis to regulate survivin expression, establishing a regulatory pathway for how the stiffness of the cellular microenvironment affects VSMC behaviors. Overall, our findings indicate that survivin is necessary for VSMC cycling and proliferation and plays a role in regulating stiffness-responsive phenotypes.

Characterisation of Lipoma-Preferred Partner as a Novel Mechanotransducer in Vascular Smooth Muscle Cells.

In arteries and arterioles, a chronic increase in blood pressure raises wall tension. This continuous biomechanical strain causes a change in gene expression in vascular smooth muscle cells (VSMCs) that may lead to pathological changes. Here we have characterised the functional properties of lipoma-preferred partner (LPP), a Lin11-Isl1-Mec3 (LIM)-domain protein, which is most closely related to the mechanotransducer zyxin but selectively expressed by smooth muscle cells, including VSMCs in adult mice. VSMCs isolated from the aorta of LPP knockout (LPP-KO) mice displayed a higher rate of proliferation than their wildtype (WT) counterparts, and when cultured as three-dimensional spheroids, they revealed a higher expression of the proliferation marker Ki 67 and showed greater invasion into a collagen gel. Accordingly, the gelatinase activity was increased in LPP-KO but not WT spheroids. The LPP-KO spheroids adhering to the collagen gel responded with decreased contraction to potassium chloride. The relaxation response to caffeine and norepinephrine was also smaller in the LPP-KO spheroids than in their WT counterparts. The overexpression of zyxin in LPP-KO VSMCs resulted in a reversal to a more quiescent differentiated phenotype. In native VSMCs, i.e., in isolated perfused segments of the mesenteric artery (MA), the contractile responses of LPP-KO segments to potassium chloride, phenylephrine or endothelin-1 did not vary from those in isolated perfused WT segments. In contrast, the myogenic response of LPP-KO MA segments was significantly attenuated while zyxin-deficient MA segments displayed a normal myogenic response. We propose that LPP, which we found to be expressed solely in the medial layer of different arteries from adult mice, may play an important role in controlling the quiescent contractile phenotype of VSMCs.