Lipid accumulation and novel insight into vascular smooth muscle cells in atherosclerosis

Blocking H1R signal aggravates atherosclerosis by promoting inflammation and foam cell formation

Atherosclerosis (AS) is a chronic inflammatory arterial disease, in which abnormal lipid metabolism and foam cell formation play key roles. Histamine is a vital biogenic amine catalyzed by histidine decarboxylase (HDC) from L-histidine. Histamine H1 receptor (H1R) antagonist is a commonly encountered anti-allergic agent in the clinic. However, the role and mechanism of H1R in atherosclerosis have not been fully elucidated. Here, we explored the effect of H1R on atherosclerosis using Apolipoprotein E-knockout (ApoE-/-) mice with astemizole (AST, a long-acting H1R antagonist) treatment. The results showed that AST increased atherosclerotic plaque area and hepatic lipid accumulation in mice. The result of microarray study identified a significant change of endothelial lipase (LIPG) in CD11b+ myeloid cells derived from HDC-knockout (HDC-/-) mice compared to WT mice. Blocking H1R promoted the formation of foam cells from bone marrow-derived macrophages (BMDMs) of mice by up-regulating p38 mitogen-activated protein kinase (p38 MAPK) and LIPG signaling pathway. Taken together, these findings demonstrate that blocking H1R signal aggravates atherosclerosis by promoting abnormal lipid metabolism and macrophage-derived foam cell formation via p38 MAPK-LIPG signaling pathway. KEY MESSAGES: Blocking H1R signal with AST aggravated atherosclerosis and increased hepatic lipid accumulation in high-fat diet (HFD)-fed ApoE-/- mice. Blocking H1R signal promoted macrophage-derived foam cell formation via p38 MAPK-LIPG signaling pathway.

Effects of a Global Rab27a Null Mutation on Murine PVAT and Cardiovascular Function

BACKGROUND

RAB27A is a member of the RAS oncogene superfamily of GTPases and regulates cell secretory function. It, is expressed within blood vessels and perivascular adipose tissue. We hypothesized that loss of RAB27A would alter cardiovascular function.

METHODS

Body weight of Rab27aash mice was measured from 2 to 18 months of age, along with glucose resorption at 6 and 12 months of age and glucose sensitivity at 18 months of age. Body weight and cellular and molecular features of perivascular adipose tissue and aortic tissue were examined in a novel C57BL/6J Rab27a null strain. Analyses included morphometric quantification and proteomic analyses. Wire myography measured vasoreactivity, and echocardiography measured cardiac function. Comparisons across ages and genotypes were evaluated via 2-way ANOVA with multiple comparison testing. Significance for myography was determined via 4-parameter nonlinear regression testing.

RESULTS

Genome-wide association data linked rare human RAB27A variants with body mass index and glucose handling. Changes in glucose tolerance were observed in Rab27aash male mice at 18 months of age. In WT (wild-type) and Rab27a null male mice, body weight, adipocyte lipid area, and aortic area increased with age. In female mice, only body weight increased with age, independent of RAB27A presence. Protein signatures from male Rab27a null mice suggested greater associations with cardiovascular and metabolic phenotypes compared with female tissues. Wire myography results showed Rab27a null males exhibited increased vasoconstriction and reduced vasodilation at 8 weeks of age. Rab27a null females exhibited increased vasoconstriction and vasodilation at 20 weeks of age. Consistent with these vascular changes, male Rab27a null mice experienced age-related cardiomyopathy, with severe differences observed by 21 weeks of age.

CONCLUSIONS

Global RAB27A loss impacted perivascular adipose tissue and thoracic aorta proteomic signatures, altered vasocontractile responses, and decreased left ventricular ejection fraction in mice.

Hsa_circ_0032389 Enhances Proliferation and Migration in PDGF-BB-Induced Human Aortic Vascular Smooth Muscle Cells

Circular RNA (circRNAs) has been confirmed to participate in atherosclerosis (AS) progression. However, the role and mechanism of hsa_circ_0032389 in AS process still need to be further revealed. This study evaluates the role and mechanism of hsa_circ_0032389 in AS process. Platelet-derived growth factor-BB (PDGF-BB) was used to induce human aortic vascular smooth muscle cells (HA-VSMCs). The expression levels of hsa_circ_0032389, microRNA (miR)-513a-5p, and fibroblast growth factor receptor substrate 2 (FRS2) were examined by quantitative real-time PCR. Cell proliferation and migration were analyzed using cell counting kit 8 assay, flow cytometry, EdU assay, transwell assay, and wound healing assay. Protein expression was assessed using western blot analysis. Dual-luciferase reporter and RIP assays were used to confirm RNA interaction. Hsa_circ_0032389 was overexpressed in PDGF-BB-induced HA-VSMCs, and its downregulation inhibited HA-VSMC viability, cell cycle, EdU positive cell rate, migratory cell number, and wound closure rate under PDGF-BB treatment. The luciferase activity of hsa_circ_0032389wt could be reduced by miR-513a-5p mimic, and both hsa_circ_0032389 and miR-513a-5p were enriched in anti-Ago2, confirming that miR-513a-5p could be sponged by hsa_circ_0032389. MiR-513a-5p inhibitor reversed the effect of hsa_circ_0032389 knockdown on PDGF-BB-induced HA-VSMC viability, cell cycle, EdU positive cell rate, migratory cell number, and wound closure rate. Moreover, the luciferase activity of FRS2wt was reduced by miR-513a-5p mimic, and both FRS2 and miR-513a-5p were enriched in anti-Ago2, verifying that FRS2 was targeted by miR-513a-5p. MiR-513a-5p suppressed PDGF-BB-induced HA-VSMC viability, cell cycle, EdU positive cell rate, migratory cell number, and wound closure rate by targeting FRS2. Our results indicated that hsa_circ_0032389 enhanced PDGF-BB-induced HA-VSMC proliferation and migration via regulating miR-513a-5p/FRS2 axis.

Navigating the landscape: Prospects and hurdles in targeting vascular smooth muscle cells for atherosclerosis diagnosis and therapy

Vascular smooth muscle cells (VSMCs) have emerged as pivotal contributors throughout all phases of atherosclerotic plaque development, effectively dispelling prior underestimations of their prevalence and significance. Recent lineage tracing studies have unveiled the clonal nature and remarkable adaptability inherent to VSMCs, thereby illuminating their intricate and multifaceted roles in the context of atherosclerosis. This comprehensive review provides an in-depth exploration of the intricate mechanisms and distinctive characteristics that define VSMCs across various physiological processes, firmly underscoring their paramount importance in shaping the course of atherosclerosis. Furthermore, this review offers a thorough examination of the significant strides made over the past two decades in advancing imaging techniques and therapeutic strategies with a precise focus on targeting VSMCs within atherosclerotic plaques, notably spotlighting meticulously engineered nanoparticles as a promising avenue. We envision the potential of VSMC-targeted nanoparticles, thoughtfully loaded with medications or combination therapies, to effectively mitigate pro-atherogenic VSMC processes. These advancements are poised to contribute significantly to the pivotal objective of modulating VSMC phenotypes and enhancing plaque stability. Moreover, our paper also delves into recent breakthroughs in VSMC-targeted imaging technologies, showcasing their remarkable precision in locating microcalcifications, dynamically monitoring plaque fibrous cap integrity, and assessing the therapeutic efficacy of medical interventions. Lastly, we conscientiously explore the opportunities and challenges inherent in this innovative approach, providing a holistic perspective on the potential of VSMC-targeted strategies in the evolving landscape of atherosclerosis research and treatment.

Current views on selenoprotein S in the pathophysiological processes of diabetes-induced atherosclerosis: potential therapeutics and underlying biomarkers

Atherosclerotic cardiovascular disease (ASCVD) consistently ranks as the primary mortality factor among diabetic people. A thorough comprehension of the pathophysiological routes and processes activated by atherosclerosis (AS) caused by diabetes mellitus (DM), together with the recognition of new contributing factors, could lead to the discovery of crucial biomarkers and the development of innovative drugs against atherosclerosis. Selenoprotein S (SELENOS) has been implicated in the pathology and progression of numerous conditions, including diabetes, dyslipidemia, obesity, and insulin resistance (IR)-all recognized contributors to endothelial dysfunction (ED), a precursor event to diabetes-induced AS. Hepatic-specific deletion of SELENOS accelerated the onset and progression of obesity, impaired glucose tolerance and insulin sensitivity, and increased hepatic triglycerides (TG) and diacylglycerol (DAG) accumulation; SELENOS expression in subcutaneous and omental adipose tissue was elevated in obese human subjects, and act as a positive regulator for adipogenesis in 3T3-L1 preadipocytes; knockdown of SELENOS in Min6 β-cells induced β-cell apoptosis and reduced cell proliferation. SELENOS also participates in the early stages of AS, notably by enhancing endothelial function, curbing the expression of adhesion molecules, and lessening leukocyte recruitment-actions that collectively reduce the formation of foam cells. Furthermore, SELENOS forestalls the apoptosis of vascular smooth muscle cells (VSMCs) and macrophages, mitigates vascular calcification, and alleviates inflammation in macrophages and CD4+ T cells. These actions help stifle the creation of unstable plaque characterized by thinner fibrous caps, larger necrotic cores, heightened inflammation, and more extensive vascular calcification-features seen in advanced atherosclerotic lesion development. Additionally, serum SELENOS could function as a potential biomarker, and SELENOS single nucleotide polymorphisms (SNPs) rs4965814, rs28628459, and rs9806366, might be effective gene markers for atherosclerosis-related diseases in diabetes. This review accentuates the pathophysiological processes of atherosclerosis in diabetes and amasses current evidence on SELENOS's potential therapeutic benefits or as predictive biomarkers in the various stages of diabetes-induced atherosclerosis.

Hypothyroidism increases angiotensinogen gene expression associated with vascular smooth muscle cells cholesterol metabolism dysfunction and aorta remodeling in Psammomys obesus

It has been previously shown that clinical cardiovascular manifestations can be caused by mild changes in thyroid function. However, the implication of angiotensinogen (Agt) and vascular smooth muscle cells (VSMCs) dysfunction in the pathophysiology of cardiovascular manifestations in hypothyroidism have not yet been investigated. We induced experimental hypothyroidism in Psammomys obesus by administering carbimazole for five months. At the end of the experiment, the animals were sacrificed and histopathological analysis was performed using Masson's trichrome staining of the aorta and thyroid gland. The expression of the Agt gene and the genes implicated in cholesterol metabolism regulation in the liver and VSMCs was determined by qRT-PCR. Histological observations revealed profound remodeling of the aorta structure in animals with hypothyroidism. In addition, Agt gene expression in the liver was significantly increased. In vitro study, showed that VSMCs from hypothyroid animals overexpressed 3-hydroxy-3-methylglutaryl coenzyme A reductase (Hmgcr) and Acyl CoA:cholesterol acyltransferase (Acat) 1, with failure to increase the efflux pathway genes (ATP-binding cassette subfamily G member (Abcg) 1 and 4). These results suggest that hypothyroidism leads to vascular alterations, including structural remodeling, VSMCs cholesterol metabolism dysfunction, and their switch to a synthetic phenotype, together with hepatic Agt gene overexpression.

Pterostilbene as a Therapeutic Alternative for Central Nervous System Disorders: A Review of the Current Status and Perspectives

Neurological disorders are diverse, have complex causes, and often result in disability; yet, effective treatments remain scarce. The resveratrol derivative pterostilbene possesses numerous physiological activities that hold promise as a novel therapy for the central nervous system (CNS) disorders. This review aimed to summarize the protective mechanisms of pterostilbene in in vitro and in vivo models of CNS disorders and the pharmacokinetics and safety to assess its possible effects on CNS disorders. Available evidence supports the protective effects of pterostilbene in CNS disorders involving mechanisms such as antioxidant and anti-inflammatory activity, regulation of lipid metabolism and vascular smooth muscle cell proliferation, improvement of synaptic function and neurogenesis, induction of glioma cell cycle arrest, and inhibition of glioma cell migration and invasion. Studies have identified possible molecular targets and pathways for the protective actions of pterostilbene in CNS disorders including the AMPK/STAT3, Akt, NF-κB, MAPK, and ERK signaling pathways. The possible pharmacological effects and molecular pathways of pterostilbene in CNS disorders are critically discussed in this review. Future studies should aim to increase our understanding of pterostilbene in animal models and humans to further evaluate its role in CNS disorders and the detailed mechanisms.

The Chinese medicine Xin-tong-tai granule protects atherosclerosis by regulating oxidative stress through NOX/ROS/NF-κB signal pathway

BACKGROUND

Xin-tong-tai Granule (XTTG), a traditional Chinese medicine, has been used to treat atherosclerosis (AS), but its mechanism is poorly understood. Intriguingly, oxidative stress has been recognized as vital factors in the treatment of atherosclerosis.

PURPOSE

This study aims to explore the potential mechanism of XTTG for treating AS.

METHODS

An in-vivo model of AS was established by feeding ApoE-/- mice with a high-fat diet (HFD), and the Human Aortic Vascular Smooth Muscle Cells (HAVSMCs) were induced by oxidized low-density lipoprotein (ox-LDL) in vitro. After treatment, the blood lipid levels and pathological aortic changes of each group were observed, and the cell proliferation and lipid droplet aggregation in each group were evaluated. The oxidative stress indicators such as malondialdehyde (MDA) and superoxide dismutase (SOD) levels and related NOX/ROS/NF-κB signaling pathway indicators were observed.

RESULTS

XTTG improved blood lipid levels and pathological aortic changes of ApoE-/- mice with HFD feeding, inhibited HAVSMCs proliferation and lipid droplet aggregation induced by ox-LDL, reduced MDA content, increased SOD content, inhibited NOX4 and p22phox protein expression, downregulated ROS content, inhibited IKK-α, IKK-β, NF-κB protein and mRNA expression and the phosphorylation of NF-κB.

CONCLUSION

XTTG can inhibit NOX/ROS/NF-κB signaling pathway, reduce damages caused by oxidative stress, and exert anti-AS effects.

CIRC_0091822 CONTRIBUTES TO THE PROLIFERATION, INVASION, AND MIGRATION OF VASCULAR SMOOTH MUSCLE CELLS UNDER OXIDIZED LOW-DENSITY LIPOPROTEIN TREATMENT

ABSTRACT

Background: Circular RNAs (circRNAs) have been shown to mediate atherosclerosis (AS) process by regulating vascular smooth muscle cells (VSMCs) function. However, whether circ_0091822 mediates VSMCs function to regulate AS process is unclear. Methods: Oxidized low-density lipoprotein (ox-LDL) was used to treat VSMCs for constructing AS cell models. Vascular smooth muscle cells proliferation, invasion, and migration were examined by cell counting kit 8 assay, EdU assay, transwell assay, and wound healing assay. Protein expression was tested by western blot analysis. The expression of circ_0091822, microRNA (miR)-339-5p, and blocking of proliferation 1 (BOP1) was determined using quantitative real-time PCR. RNA interaction was examined using dual-luciferase reporter assay and RIP assay. Results: Ox-LDL treatment enhanced VSMCs proliferation, invasion, and migration. Circ_0091822 was overexpressed in the serum of AS patients and ox-LDL-induced VSMCs. Circ_0091822 knockdown inhibited ox-LDL-induced VSMCs proliferation, invasion, and migration. Circ_0091822 sponged miR-339-5p, and miR-339-5p inhibitor reversed the function of circ_0091822 knockdown. MiR-339-5p targeted BOP1, and BOP1 also reversed the repressing effect of miR-339-5p on ox-LDL-induced VSMCs functions. Circ_0091822/miR-339-5p/BOP1 axis promoted the activity of Wnt/β-catenin pathway. Conclusions: Circ_0091822 might be a therapeutic target for AS, which facilitated ox-LDL-induced VSMCs proliferation, invasion, and migration through modulating miR-339-5p/BOP1/Wnt/β-catenin pathway.

Roles of protein post-translational modifications in glucose and lipid metabolism: mechanisms and perspectives

The metabolism of glucose and lipids is essential for energy production in the body, and dysregulation of the metabolic pathways of these molecules is implicated in various acute and chronic diseases, such as type 2 diabetes, Alzheimer's disease, atherosclerosis (AS), obesity, tumor, and sepsis. Post-translational modifications (PTMs) of proteins, which involve the addition or removal of covalent functional groups, play a crucial role in regulating protein structure, localization function, and activity. Common PTMs include phosphorylation, acetylation, ubiquitination, methylation, and glycosylation. Emerging evidence indicates that PTMs are significant in modulating glucose and lipid metabolism by modifying key enzymes or proteins. In this review, we summarize the current understanding of the role and regulatory mechanisms of PTMs in glucose and lipid metabolism, with a focus on their involvement in disease progression associated with aberrant metabolism. Furthermore, we discuss the future prospects of PTMs, highlighting their potential for gaining deeper insights into glucose and lipid metabolism and related diseases.

Extracellular vesicles in atherosclerosis and vascular calcification: the versatile non-coding RNAs from endothelial cells and vascular smooth muscle cells

Atherosclerosis (AS) is characterized by the accumulation of lipids, fibrous elements, and calcification in the innermost layers of arteries. Vascular calcification (VC), the deposition of calcium and phosphate within the arterial wall, is an important characteristic of AS natural history. However, medial arterial calcification (MAC) differs from intimal calcification and cannot simply be explained as the consequence of AS. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are directly involved in AS and VC processes. Understanding the communication between ECs and VSMCs is critical in revealing mechanisms underlying AS and VC. Extracellular vesicles (EVs) are found as intercellular messengers in kinds of physiological processes and pathological progression. Non-coding RNAs (ncRNAs) encapsulated in EVs are involved in AS and VC, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). The effects of ncRNAs have not been comprehensively understood, especially encapsulated in EVs. Some ncRNAs have demonstrated significant roles in AS and VC, but it remains unclear the functions of the majority ncRNAs detected in EVs. In this review, we summarize ncRNAs encapsulated in EC-EVs and VSMC-EVs, and the signaling pathways that are involved in AS and VC.

MALT1 accelerates proatherogenic vascular smooth muscle cell growth, invasion and synthetic phenotype switching via nuclear factor‑κB signaling‑dependent way

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) modulates T helper cell differentiation and nuclear factor-κB (NF-κB) pathway-mediated inflammation and potentially regulates lipid metabolism, which are all critical factors involved in atherosclerosis. The present study aimed to investigate the effect of MALT1 on the cellular functions of proatherogenic vascular smooth muscle cells (VSMCs). Therefore, to establish a human proatherogenic VSMC model, VSMCs were treated with different doses of oxidized low-density lipoprotein (oxLDL). Subsequently, the effect of MALT1 overexpression or knockdown in proatherogenic VSMCs treated with or without NF-κB activator was also explored. The results showed that treatment of proatherogenic VSMCs with oxLDL significantly elevated the mRNA and protein expression levels of MALT1 in a dose-dependent manner. Furthermore, MALT1 overexpression enhanced cell viability, invasion and phenotype switching and reduced apoptosis in proatherogenic VSMCs. However, MALT1 knockdown exerted the opposite effect on the above cellular functions. Additionally, the results revealed that MALT1 could positively regulate the NF-κB pathway in proatherogenic VSMCs. Moreover, treatment of proatherogenic VSMCs with NF-κB activator not only exacerbated the dysregulation of cellular functions, but also hampered the effect of MALT1 knockdown on attenuating cell growth, invasion and synthetic phenotype switching, thus suggesting that NF-κB was essential for the regulation of MALT1-triggered functions in proatherogenic VSMCs. In conclusion, the current study suggested that MALT1 could exacerbate cell viability, mobility and synthetic phenotype switching of proatherogenic VSMCs in a NF-κB signaling-dependent manner. Therefore, MALT1 could be considered as a potential therapeutic target for atherosclerosis.

Vascular smooth muscle cells in intracranial aneurysms

Intracranial aneurysm (IA) is a severe cerebrovascular disease characterized by abnormal bulging of cerebral vessels that may rupture and cause a stroke. The expansion of the aneurysm accompanies by the remodeling of vascular matrix. It is well-known that vascular remodeling is a process of synthesis and degradation of extracellular matrix (ECM), which is highly dependent on the phenotype of vascular smooth muscle cells (VSMCs). The phenotypic switching of VSMC is considered to be bidirectional, including the physiological contractile phenotype and alternative synthetic phenotype in response to injury. There is increasing evidence indicating that VSMCs have the ability to switch to various phenotypes, including pro-inflammatory, macrophagic, osteogenic, foamy and mesenchymal phenotypes. Although the mechanisms of VSMC phenotype switching are still being explored, it is becoming clear that phenotype switching of VSMCs plays an essential role in IA formation, progression, and rupture. This review summarized the various phenotypes and functions of VSMCs associated with IA pathology. The possible influencing factors and potential molecular mechanisms of the VSMC phenotype switching were further discussed. Understanding how phenotype switching of VSMC contributed to the pathogenesis of unruptured IAs can bring new preventative and therapeutic strategies for IA.

Diversity of arterial cell and phenotypic heterogeneity induced by high-fat and high-cholesterol diet

Lipid metabolism disorder is the basis of atherosclerotic lesions, in which cholesterol and low-density lipoprotein (LDL) is the main factor involved with the atherosclerotic development. A high-fat and high-cholesterol diet can lead to this disorder in the human body, thus accelerating the process of disease. The development of single-cell RNA sequencing in recent years has opened the possibility to unbiasedly map cellular heterogeneity with high throughput and high resolution; alterations mediated by a high-fat and high-cholesterol diet at the single-cell transcriptomic level can be explored with this mean afterward. We assessed the aortic arch of 16-week old Apoe-/- mice of two control groups (12 weeks of chow diet) and two HFD groups (12 weeks of high fat, high cholesterol diet) to process single-cell suspension and use single-cell RNA sequencing to anatomize the transcripts of 5,416 cells from the control group and 2,739 from the HFD group. Through unsupervised clustering, 14 cell types were divided and defined. Among these cells, the cellular heterogeneity exhibited in endothelial cells and immune cells is the most prominent. Subsequent screening delineated ten endothelial cell subsets with various function based on gene expression profiling. The distribution of endothelial cells and immune cells differs significantly between the control group versus the HFD one. The existence of pathways that inhibit atherosclerosis was found in both dysfunctional endothelial cells and foam cells. Our data provide a comprehensive transcriptional landscape of aortic arch cells and unravel the cellular heterogeneity brought by a high-fat and high-cholesterol diet. All these findings open new perspectives at the transcriptomic level to studying the pathology of atherosclerosis.

Role of Lipoprotein Levels and Function in Atherosclerosis Associated with Autoimmune Rheumatic Diseases

Immune and inflammatory mediators in autoimmune rheumatic diseases induce modification in the activity of enzymes pivotal for lipid metabolism and promote a proatherogenic serum lipid profile. However, disturbances in low- and high-density lipoprotein composition and increased lipid oxidation also occur. Therefore, lipoprotein dysfunction causes intracellular cholesterol accumulation in macrophages, smooth muscle cells, and platelets. Overall, both plaque progression and acute cardiovascular events are promoted. Single rheumatic diseases may present a particular pattern of lipid disturbances so that standard methods to evaluate cardiovascular risk may not be accurate enough. In general, antirheumatic drugs positively affect lipid metabolism in these patients.

Recent advances of traditional Chinese medicine for the prevention and treatment of atherosclerosis

ETHNOPHARMACOLOGICAL RELEVANCE

Atherosclerosis (AS) is a common systemic disease with increasing morbidity and mortality worldwide. Traditional Chinese medicine (TCM) with characteristics of multiple pathways and targets, presents advantages in the diagnosis and treatment of atherosclerosis.

AIM OF THE STUDY

With the modernization of TCM, the active ingredients and molecular mechanisms of TCM for AS treatment have been gradually revealed. Therefore, it is necessary to examine the existing studies on TCM therapies aimed at regulating AS over the past two decades.

MATERIALS AND METHODS

Using "atherosclerosis" and "Traditional Chinese medicine" as keywords, all relevant TCM literature published in the last 10 years was collected from electronic databases (such as Elsevier, Springer, PubMed, CNKI, and Web of Science), books and papers until March 2022, and the critical information was statistically analyzed.

RESULTS

In this review, we highlighted extracts of 8 single herbs, a total of 41 single active ingredients, 20 TCM formulae, and 25 patented drugs, which were described with chemical structure, source, model, efficacy and potential mechanism.

CONCLUSION

We summarized the cytopathological basis for the development of atherosclerosis involving vascular endothelial cells, macrophages and vascular smooth muscle cells, and categorically elaborated the medicinal TCM used for AS, all of which provide the current evidence on the better management of atherosclerosis by TCM.

HSPB1 Regulates Autophagy and Apoptosis in Vascular Smooth Muscle Cells in Arteriosclerosis Obliterans

Objective

Small heat shock protein-1 (HSPB1) is a small heat shock protein that participates in many cellular processes and alleviates stress-induced cell injury. Autophagy protects cells from many types of stress and plays a key role in preventing stress in arteriosclerosis obliterans (ASO). However, the roles of HSPB1 in autophagy and apoptosis in the context of ASO pathogenesis remain unclear.

Methods

In vivo and in vitro studies were used to determine whether HSPB1 is associated with ASO progression. The expression of HSPB1 was measured in normal and sclerotic blood vessels. The role of HSPB1 and its potential downstream signaling pathway were determined in VSMCs by overexpressing and silencing HSPB1.

Results

A total of 91 ASO patients admitted to and treated at our hospital from Sep. 2020 to Sep. 2021 were selected, and plasma HSPB1 expression was assessed. We divided the patients with ASO into the grade I (n = 39), II (n = 29), III (n = 10), and IV (n = 13) groups according to Fontaine's classification. Plasma HSPB1 levels were markedly decreased in patients with grade III (n = 10) and IV (n = 13) ASO compared with patients with grade I ASO. Furthermore, HSPB1 expression was significantly decreased, and p62 and cleaved caspase-3 were increased in the sclerotic vasculature compared to the normal vasculature (p < 0.05). Overexpression of HSPB1 promoted apoptosis of VSMCs following ox-LDL treatment. Knockdown of HSPB1 led to a marked increase in the expression of LC3II and Beclin-1 in ox-LDL-stimulated VSMCs, whereas knockdown of HSPB1 attenuated these changes (p < 0.05). Importantly, overexpression of HSPB1 promoted the dephosphorylation of JNK in ox-LDL-stimulated VSMCs. Conversely, downregulation of HSPB1 induced the opposite change.

Conclusion

Loss of HSPB1 promotes VSMC autophagy and inhibits VSMC apoptosis, which are associated with ASO. HSPB1 and its downstream signaling pathways could be potential therapeutic targets for ASO treatment.

Dexamethasone suppresses the proliferation and migration of VSMCs by FAK in high glucose conditions

Background

High glucose conditions cause some changes in the vessels of diabetes through the signal transduction pathways. Dexamethasone and other corticosteroids have a wide range of biological effects in immunological events. In the present study, the effects of dexamethasone were investigated on the VSMC (vascular smooth muscle cell) proliferation, and migration based on the FAK gene and protein changes in high glucose conditions.

Methods and materials

The vascular smooth muscle cells were cultured in DMEM and were treated with dexamethasone (10^–7 M, 10^–6 M, and 10^–5 M) for 24, and 48 h in high glucose conditions. The cell viability was estimated by MTT method. The FAK gene expression levels and pFAK protein values were determined by RT-qPCR and western blotting techniques, respectively. A scratch assay was used to evaluate cellular migration.

Results

The FAK gene expression levels decreased significantly dependent on dexamethasone doses at 24 and 48 h. The pFAK protein values decreased significantly with a time lag at 24- and 48-h periods as compared with gene expression levels.

Conclusion

The results showed that the inhibition of VSMC proliferation and migration by dexamethasone in the high glucose conditions may be related to the changes of FAK.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00604-3.

Silencing METTL3 Stabilizes Atherosclerotic Plaques by Regulating the Phenotypic Transformation of Vascular Smooth Muscle Cells via the miR-375-3p/PDK1 Axis

PURPOSE

Atherosclerosis (AS) is a primary cause of cardiovascular diseases. This study investigated the mechanism of methyltransferase-like 3 (METTL3) in AS plaques via modulating the phenotypic transformation of vascular smooth muscle cells (VSMCs).

METHODS

AS mouse models and MOVAS cell models were established through high-fat diet and the treatment of ox-LDL, respectively. METTL3 expression in AS models was detected via RT-qPCR and Western blot. The AS plaques, lipid deposition, and collagen fibers were examined via histological staining. The levels of Ly-6c, α-SMA, and OPN were examined via Western blot. The blood lipid indexes in mouse aortic tissues were determined using kits. The proliferation and migration of MOVAS cells were detected via CCK-8 and Transwell assays. The m⁶A modification level of mRNA was quantified. The binding relationship between pri-miR-375 and DGCR8, and the enrichment of m⁶A on pri-miR-375 were detected via RIP. The binding relationship between miR-375-3p and 3-phosphoinositide-dependent protein kinase-1 (PDK1) was verified via dual-luciferase assay. Joint experiments were designed to investigate the role of miR-375-3P/PDK1 in the phenotypic transformation of VSMCs.

RESULTS

METTL3 was highly expressed in AS. Silencing METTL3 alleviated AS progression and stabilized AS plaques in mice, and limited the phenotypic transformation of VSMCs induced by ox-LDL. Silencing METTL3 inhibited m⁶A level and decreased the binding of DGCR8 to pri-miR-375 and further limited miR-375-3p expression. miR-375-3p targeted PDK1 transcription. miR-375-3p upregulation or PDK1 downregulation facilitated the phenotypic transformation of VSMCs.

CONCLUSION

METTL3-mediated m⁶A modification promoted VSMC phenotype transformation and made AS plaques more vulnerable via the miR-375-3p/PDK1 axis.