Apoptosis Of Vascular Smooth Muscle Cells Research Articles

Pentamethylquercetin attenuates angiotensin II-induced abdominal aortic aneurysm formation by blocking nuclear translocation of C/EBPβ at Lys253

BackgroundPentamethylquercetin (PMQ) is a natural polymethyl flavonoid that possesses anti-apoptotic and other biological properties. Abdominal aortic aneurysm (AAA), a fatal vascular disease with a high risk of rupture, is associated with phenotypic switching and apoptosis of medial vascular smooth muscle cells (VSMCs). This study aimed to investigate the protective effects of PMQ on the development of AAA and the underlying mechanism. MethodsApoE−/− mice were continuously infused with angiotensin II (Ang II) for 4 weeks to develop the AAA model. Intragastric administration of PMQ was initiated 5 days before Ang II infusion and continued for 4 weeks. In vitro, VSMCs were cultured and pretreated with PMQ, stimulated with Ang II. Real-time PCR, western blotting, and immunofluorescence staining were used to examine the roles and mechanisms of PMQ on the phenotypic switching and apoptosis of VSMCs. ResultsPMQ dose-dependently reduced the incidence of Ang II-induced AAA, aneurysm diameter enlargement, elastin degradation, VSMCs phenotypic switching and apoptosis. Furthermore, PMQ also inhibited phenotypic switching and apoptosis in Ang II-stimulated VSMCs. PMQ exerted protective effects by regulating the C/EBPβ/PTEN/AKT/GSK-3β axis. AAV-mediated overexpression of PTEN reduced the therapeutic effects of PMQ in the AAA model mice, suggesting that the effects of PMQ on Ang II-mediated AAA formation were related to the PTEN/AKT/GSK-3β axis. PMQ inhibited VSMCs phenotypic switching and apoptosis by bounding to C/EBPβ at Lys253 with hydrogen bond to regulate C/EBPβ nuclear translocation and PTEN/AKT/GSK-3β axis, thereby inhibiting Ang II-induced AAA formation. ConclusionsPentamethylquercetin inhibits angiotensin II-induced abdominal aortic aneurysm formation by bounding to C/EBPβ at Lys253. Therefore, PMQ prevents the formation of AAA and reduces the incidence of AAA.

Spatiotemporal ATF3 Expression Determines VSMC Fate in Abdominal Aortic Aneurysm.

Abdominal aortic aneurysm (AAA) is a catastrophic disease with little effective therapy, likely due to the limited understanding of the mechanisms underlying AAA development and progression. Activating transcription factor (ATF) 3 has been increasingly recognized as a key regulator of cardiovascular diseases. However, the role of ATF3 (activating transcription factor 3) in AAA development and progression remains elusive. Genome-wide RNA sequencing analysis was performed on the aorta isolated from saline or Ang II (angiotensin II)-induced AAA mice, and ATF3 was identified as the potential key gene for AAA development. To examine the role of ATF3 in AAA development, vascular smooth muscle cell-specific ATF3 knockdown or overexpressed mice by recombinant adenoassociated virus serotype 9 vectors carrying ATF3, or shRNA-ATF3 with SM22α (smooth muscle protein 22-α) promoter were used in Ang II (angiotensin II)-induced AAA mice. In human and murine vascular smooth muscle cells, gain or loss of function experiments were performed to investigate the role of ATF3 in vascular smooth muscle cell proliferation and apoptosis. In both Ang II-induced AAA mice and patients with AAA, the expression of ATF3 was reduced in aneurysm tissues but increased in aortic lesion tissues. The deficiency of ATF3 in vascular smooth muscle cell promoted AAA formation in Ang II-induced AAA mice. PDGFRB (platelet-derived growth factor receptor β) was identified as the target of ATF3, which mediated vascular smooth muscle cell proliferation in response to TNF-alpha (tumor necrosis factor-α) at the early stage of AAA. ATF3 suppressed the mitochondria-dependent apoptosis at the advanced stage by upregulating its direct target BCL2. Our chromatin immunoprecipitation results also demonstrated that the recruitment of NFκB1 and P300/BAF/H3K27ac complex to the ATF3 promoter induces ATF3 transcription via enhancer activation. NFKB1 inhibitor (andrographolide) inhibits the expression of ATF3 by blocking the recruiters NFKB1 and ATF3-enhancer to the ATF3-promoter region, ultimately leading to AAA development. Our results demonstrate a previously unrecognized role of ATF3 in AAA development and progression, and ATF3 may serve as a novel therapeutic and prognostic marker for AAA.

The role of transcription factors in the pathogenesis and therapeutic targeting of vascular diseases.

Transcription factors (TFs) constitute an essential component of epigenetic regulation. They contribute to the progression of vascular diseases by regulating epigenetic gene expression in several vascular diseases. Recently, numerous regulatory mechanisms related to vascular pathology, ranging from general TFs that are continuously activated to histiocyte-specific TFs that are activated under specific circumstances, have been studied. TFs participate in the progression of vascular-related diseases by epigenetically regulating vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs). The Krüppel-like family (KLF) TF family is widely recognized as the foremost regulator of vascular diseases. KLF11 prevents aneurysm progression by inhibiting the apoptosis of VSMCs and enhancing their contractile function. The presence of KLF4, another crucial member, suppresses the progression of atherosclerosis (AS) and pulmonary hypertension by attenuating the formation of VSMCs-derived foam cells, ameliorating endothelial dysfunction, and inducing vasodilatory effects. However, the mechanism underlying the regulation of the progression of vascular-related diseases by TFs has remained elusive. The present study categorized the TFs involved in vascular diseases and their regulatory mechanisms to shed light on the potential pathogenesis of vascular diseases, and provide novel insights into their diagnosis and treatment.

G6PD maintains the VSMC synthetic phenotype and accelerates vascular neointimal hyperplasia by inhibiting the VDAC1-Bax-mediated mitochondrial apoptosis pathway.

Glucose-6-phosphate dehydrogenase (G6PD) plays an important role in vascular smooth muscle cell (VSMC) phenotypic switching, which is an early pathogenic event in various vascular remodeling diseases (VRDs). However, the underlying mechanism is not fully understood. An IP‒LC‒MS/MS assay was conducted to identify new binding partners of G6PD involved in the regulation of VSMC phenotypic switching under platelet-derived growth factor-BB (PDGF-BB) stimulation. Co-IP, GST pull-down, and immunofluorescence colocalization were employed to clarify the interaction between G6PD and voltage-dependent anion-selective channel protein 1 (VDAC1). The molecular mechanisms involved were elucidated by examining the interaction between VDAC1 and apoptosis-related biomarkers, as well as the oligomerization state of VDAC1. The G6PD level was significantly elevated and positively correlated with the synthetic characteristics of VSMCs induced by PDGF-BB. We identified VDAC1 as a novel G6PD-interacting molecule essential for apoptosis. Specifically, the G6PD-NTD region was found to predominantly contribute to this interaction. G6PD promotes VSMC survival and accelerates vascular neointimal hyperplasia by inhibiting VSMC apoptosis. Mechanistically, G6PD interacts with VDAC1 upon stimulation with PDGF-BB. By competing with Bax for VDAC1 binding, G6PD reduces VDAC1 oligomerization and counteracts VDAC1-Bax-mediated apoptosis, thereby accelerating neointimal hyperplasia. Our study showed that the G6PD-VDAC1-Bax axis is a vital switch in VSMC apoptosis and is essential for VSMC phenotypic switching and neointimal hyperplasia, providing mechanistic insight into early VRDs.

CircCDYL Contributes to Apoptosis, Ferroptosis, and Oxidative Stress of Ang II-Induced Vascular Smooth Muscle Cells in Thoracic Aortic Aneurysm.

Circular RNAs (circRNAs) have important regulation in thoracic aortic aneurysm (TAA). The function and mechanism of circCDYL (circ_0008285) was explored in TAA here. Angiotensin II (Ang II) was used to construct a TAA model. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed for the detection of circCDYL, miR-1270, and a disintegrin and metalloproteinase 10 (ADAM10). Cell viability was examined via cell counting kit-8 (CCK-8) assay and proliferation was analyzed using Ethynyl-2'-deoxyuridine (EdU) assay. Apoptosis rate was assessed via flow cytometry. Western blot was used for protein detection. Oxidative stress was evaluated by commercial kits. CircCDYL was upregulated in TAA tissues and Ang II-induced circCDYL upregulation in vascular smooth muscle cells (VSMCs). Knockdown of circCDYL weakened Ang II-aroused inhibition of viability, proliferation, and promotion of apoptosis, ferroptosis, and oxidative stress in VSMCs. CircCDYL served as a miR-1270 sponge. The mitigated regulation of circCDYL knockdown for Ang II-induced injury was restored after miR-1270 downregulation. CircCDYL positively regulated ADAM10 through interacting with miR-1270. Overexpression of miR-1270 abated Ang II-induced injury by downregulating ADAM10. In conclusion, circCDYL was involved in the Ang II-induced VSMC injury in TAA via the miR-1270/ADAM10 axis.

Cannabidiol protects against acute aortic dissection by inhibiting macrophage infiltration and PMAIP1-induced vascular smooth muscle cell apoptosis

Acute aortic dissection (AAD) progresses rapidly and is associated with high mortality; therefore, there remains an urgent need for pharmacological agents that can protect against AAD. Herein, we examined the therapeutic effects of cannabidiol (CBD) in AAD by establishing a suitable mouse model. In addition, we performed human AAD single-cell RNA sequencing and mouse AAD bulk RNA sequencing to elucidate the potential underlying mechanism of CBD. Pathological assays and in vitro studies were performed to verify the results of the bioinformatic analysis and explore the pharmacological function of CBD. In a β-aminopropionitrile (BAPN)-induced AAD mouse model, CBD reduced AAD-associated morbidity and mortality, alleviated abnormal enlargement of the ascending aorta and aortic arch, and suppressed macrophage infiltration and vascular smooth muscle cell (VSMC) apoptosis. Bioinformatic analysis revealed that the pro-apoptotic gene PMAIP1 was highly expressed in human and mouse AAD samples, and CBD could inhibit Pmaip1 expression in AAD mice. Using human aortic VSMCs (HAVSMCs) co-cultured with M1 macrophages, we revealed that CBD alleviated HAVSMCs mitochondrial-dependent apoptosis by suppressing the BAPN-induced overexpression of PMAIP1 in M1 macrophages. PMAIP1 potentially mediates HAVSMCs apoptosis by regulating Bax and Bcl2 expression. Accordingly, CBD reduced AAD-associated morbidity and mortality and mitigated the progression of AAD in a mouse model. The CBD-induced effects were potentially mediated by suppressing macrophage infiltration and PMAIP1 (primarily expressed in macrophages)-induced VSMC apoptosis. Our findings offer novel insights into M1 macrophages and HAVSMCs interaction during AAD progression, highlighting the potential of CBD as a therapeutic candidate for AAD treatment.

Terazosin attenuates abdominal aortic aneurysm formation by downregulating Peg3 expression to inhibit vascular smooth muscle cell apoptosis and senescence

Abdominal aortic aneurysm (AAA), a vascular degenerative disease, is a potentially life-threatening condition characterised by the loss of vascular smooth muscle cells (VSMCs), degradation of extracellular matrix (ECM), inflammation, and oxidative stress. Despite the severity of AAA, effective drugs for treatment are scarce. At low doses, terazosin (TZ) exerts antiapoptotic and anti-inflammatory effects in several diseases, but its potential to protect against AAA remains unexplored. Herein, we investigated the effects of TZ in two AAA animal models: Angiotensin II (Ang II) infusion in Apoe−/− mice and calcium chloride application in C57BL/6J mice. Mice were orally administered with TZ (100 or 1000 μg/kg/day). The in vivo results indicated that low-dose TZ alleviated AAA formation in both models. Low-dose TZ significantly reduced aortic pulse wave velocity without exerting an apparent antihypertensive effect in the Ang II-induced AAA model. Paternally expressed gene 3 (Peg3) was identified via RNA sequencing as a novel TZ target. PEG3 expression was significantly elevated in both mouse and human AAA tissues. TZ suppressed PEG3 expression and reduced the abundance of matrix metalloproteinases (MMP2/MMP9) in the tunica media. Functional experiments and molecular analyses revealed that TZ (10 nM) treatment and Peg3 knockdown effectively prevented Ang II-induced VSMC senescence and apoptosis in vitro. Thus, Peg3, a novel target of TZ, mediates inflammation-induced VSMC apoptosis and senescence. Low-dose TZ downregulates Peg3 expression to attenuate AAA formation and ECM degradation, suggesting a promising therapeutic strategy for AAA.

PCSK9 increases vulnerability of carotid plaque by promoting mitochondrial dysfunction and apoptosis of vascular smooth muscle cells.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been recognized as a novel lipid-lowing target. Recent clinical studies suggested the value of inhibiting PCSK9 in decreasing the vulnerability of coronary plaques. However, the evidence of PCSK9-regulated evolution of unstable carotid plaques is unclear, which has limited the use of PCSK9 inhibitor in carotid plaques. This study aimed to determine the effect and molecular mechanisms of PCSK9 on vulnerability of carotid plaques, to provide potential therapeutic targets for stabilizing carotid plaques. The expression of PCSK9 in stable and unstable carotid plaques were examined in tissue and plasma. Human aortic vascular smooth muscle cells (VSMCs) and carotid VSMCs were employed to transfect lentivirus for overexpression and knockdown of PCSK9, respectively. Morphological and functional changes of mitochondria were observed by live-cell imaging. Cell apoptosis was evaluated by propidium iodide staining. RNA-sequencing and biological examinations were performed to explore and validate the underlying mechanisms. Truncated plasmids were employed to identify the functional domain of PCSK9 in regulation of VSMCs' mitochondrial morphology, function and apoptosis. Clinically, PCSK9 was closely related with vulnerability of human carotid plaques. Increased expression of PCSK9 in human VSMCs was accompanied by higher level of apoptosis. At subcellular level of VSMCs, the morphology of mitochondria was shifted toward the fission state, followed by mitochondrial dysfunction. Inhibition of p38 MAPK activation partially rescued the above morphological and behavioral changes caused by PCSK9. Furthermore, inhibiting of dynamin-related protein 1 (DRP1) attenuated PCSK9-related mitochondrial dysfunction and cell apoptosis. The 1-149aa domain of PCSK9 protein was essential to achieve functional regulation to VSMCs. Our findings demonstrated that PCSK9 induced morphology-related mitochondrial dysfunction and apoptosis of VSMCs, which may be related to increased vulnerability of carotid plaque.

Interaction of Sp1 and Setd8 promotes vascular smooth muscle cells apoptosis by activating Mark4 in vascular calcification.

Vascular calcification (VC) is directly related to high mortality in chronic kidney disease (CKD), and cellular apoptosis of vascular smooth muscle cells (VSMCs) is a crucial process in the initiation of VC. Microtubule affinity-regulating kinase 4 (Mark4), known as a serine/threonine protein kinase, can induce cell apoptosis and autophagy by modulating Akt phosphorylation. However, the potential functions and molecular mechanisms of Mark4 in VSMCs apoptosis and calcification need to be further explored. Initially, our data indicated that the mRNA expression of Mark4 was prominently elevated in high phosphorus-stimulated human VSMCs compared with the other members in Marks. Consistently, Mark4 expression was found to be significantly increased in the calcified arteries of both CKD patients and rats. In vitro, silencing Mark4 suppressed apoptosis-specific marker expression by promoting Akt phosphorylation, finally attenuating VSMCs calcification induced by high phosphate. Mechanically, the transcription factor Sp1 was enriched in the Mark4 promoter region and modulated Mark4 transcription. Moreover, SET domain-containing protein 8 (Setd8) was proved to interact with Sp1 and jointly participated in the transcriptional regulation of Mark4. Finally, rescue experiments revealed that Setd8 contributed to VSMCs apoptosis and calcification by modulating Mark4 expression. In conclusion, these findings reveal that Mark4 is transcriptionally activated by Sp1, which is interacted with Setd8, to promote VSMCs calcification through Akt-mediated antiapoptotic effects, suggesting that Mark4 represents a potent and promising therapeutic target for VC in CKD.

Paraspeckle protein NONO attenuates vascular calcification by inhibiting bone morphogenetic protein 2 transcription

Vascular calcification is a pathological process commonly associated with atherosclerosis, chronic kidney disease, and diabetes. Paraspeckle protein NONO is a multifunctional RNA/DNA binding protein involved in many nuclear biological processes but its role in vascular calcification remains unclear. Here, we observed that NONO expression was decreased in calcified arteries of mice and patients with CKD. We generated smooth muscle-specific NONO-knockout mice and established three different mouse models of vascular calcification by means of 5/6 nephrectomy, adenine diet to induce chronic kidney failure, or vitamin D injection. The knockout mice were more susceptible to the development of vascular calcification relative to control mice, as verified by an increased calcification severity and calcium deposition. Likewise, aortic rings from knockout mice showed more significant vascular calcification than those from control mice ex vivo. In vitro, NONO deficiency aggravated high phosphate-induced vascular smooth muscle cell osteogenic differentiation and apoptosis, whereas NONO overexpression had a protective effect. Mechanistically, we demonstrated that the regulation of vascular calcification by NONO was mediated by bone morphogenetic protein 2 (BMP2). NONO directly bound to the BMP2 promoter using its C-terminal region, exerting an inhibitory effect on the transcription of BMP2. Thus, our study reveals that NONO is a novel negative regulator of vascular calcification, which inhibits osteogenic differentiation of vascular smooth muscle cell and vascular calcification via negatively regulating BMP2 transcription. Hence, NONO may provide a promising target for the prevention and treatment of vascular calcification.

HSPB6 Deficiency Promotes the Development of Aortic Dissection and Rupture

To better understand the pathogenesis of acute type A aortic dissection, high-sensitivity liquid chromatography–tandem mass spectrometry/mass spectrometry (LC-MS/MS)-based proteomics and phosphoproteomics approaches were used to identify differential proteins. Heat shock protein family B (small) member 6 (HSPB6) in aortic dissection was significantly reduced in human and mouse aortic dissection samples by real-time PCR, western blotting, and immunohistochemical staining techniques. Using an HSPB6-knockout mouse, we investigated the potential role of HSPB6 in β-aminopropionitrile monofumarate-induced aortic dissection. We found increased mortality and increased probability of ascending aortic dissection after HSPB6 knockout compared with wild-type mice. Mechanistically, our data suggest that HSPB6 deletion promoted vascular smooth muscle cell apoptosis. More importantly, HSPB6 deletion attenuated cofilin activity, leading to excessive smooth muscle cell stiffness and eventually resulting in the development of aortic dissection and rupture. Our data suggest that excessive stiffness of vascular smooth muscle cells caused by HSPB6 deficiency is a new pathogenetic mechanism leading to aortic dissection.

The Key Role of Liraglutide in Preventing Autophagy of Vascular Smooth Muscle Cells in High Glucose Conditions

The glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide (LIRA) is a potential hypoglycemic drug with anti-atherosclerosis (AS) effects. Autophagy in the vascular smooth muscle cells (VSMCs) facilitates AS. However, the role of autophagy in the anti-AS mechanism of LIRA remains unclear. To examine the role and mechanisms of autophagy in LIRA’s improvement of the biological characteristics of VSMCs in high glucose conditions. Experimental animal study. VSMCs isolated from the thoracic aorta of male SD rats were subjected to a high glucose (HG) condition (25 mM) in Dulbecco’s Modified Eagle’s Medium with or without LIRA, the GLP-1 receptor antagonist exendin9-39 (Exe9-39), a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), and autophagy inhibitors (3-methyladenine [3-MA] and bafilomycin A1 [Baf A1]). Acridine orange staining, western blotting, transmission electron microscopy, and mCherry-GFP-LC3 transfection were performed to evaluate the autophagy flux. Additionally, VSMC migration, calcification, proliferation, and apoptosis in HG conditions were observed. Addition of LIRA alone or in combination with autophagy inhibitors significantly downregulated Beclin, increased the LC3-II/LC3-I ratio, and upregulated p62 in VSMCs in HG conditions. Furthermore, autophagolysosome formation was markedly curbed after treatment with LIRA and/or autophagy inhibitors. Inhibition of autophagy by LIRA and/or the autophagy inhibitors attenuated VSMC phenotype conversion, proliferation, migration, and calcification and promoted VSMC apoptosis in HG conditions. This protective role of LIRA was augmented by LY294002, but inhibited by Exe9-39. LIRA plays a significant role in the improvement of the biological features of VSMCs in HG conditions.

Knockdown of LINC01128 Downregulates FUT8 to Inhibit OxLDL-Induced Vascular Smooth Muscle Cell Apoptosis in Atherosclerosis.

The apoptosis of vascular smooth muscle cells (VSMCs) contributes to the progression of atherosclerosis (AS). Long intergenic non-protein coding RNA 1128 (LINC01128) has been implicated in AS, and this study aims to uncover the role and mechanism of LINC01128 in regulating oxidized low-density lipoprotein (oxLDL)-induced VSMCs. The position of LINC01128 in cells and its target genes were predicted using bioinformatics. The localization of LINC01128 in human VSMCs was determined through fluorescence in situ hybridization. VSMCs were transfected, and the interaction between LINC01128 and fucosyltransferase 8 (FUT8) was validated by chromatin immunoprecipitation assay. The apoptotic VSMC model was established using oxLDL. LINC01128 expression in VSMCs was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and FUT8 expression was detected by qRT-PCR and western blot. VSMC viability, migration, invasion abilities, and apoptosis were assessed using cell counting kit-8, transwell assay, and flow cytometry, respectively. OxLDL (200 μg/mL) upregulated the expression of LINC01128 and FUT8 mRNA, as well as FUT8 protein, in VSMCs. LINC01128 was expressed in the nucleus of VSMCs and bound to FUT8. Knockdown of LINC01128 alleviated the inhibitory effects of oxLDL (200 μg/mL) on viability, migration, and invasion, and mitigated the promotion of apoptosis and FUT8 expression in VSMCs. On the other hand, FUT8 overexpression enhanced the suppressive effects of oxLDL (200 μg/mL) on viability, migration, and invasion activities, and amplified the facilitating effect of oxLDL on apoptosis in VSMCs. Moreover, FUT8 overexpression reversed the impact of LINC01128 silencing on viability, migration, invasion, and apoptosis in oxLDL-stimulated VSMCs. The knockdown of LINC01128 downregulates FUT8, inhibiting the progression of VSMCs in AS.

OxLDL-Stimulated Macrophages Transmit Exosomal MicroRNA-320b to Aggravate Viability, Invasion, and Phenotype Switching via Regulating PPARGC1A-Mediated MEK/ERK Pathway in Proatherogenic Vascular Smooth Muscle Cells.

Our previous study revealed oxidized-low density lipoprotein (oxLDL)-stimulated macrophages delivered exosomes to exacerbate vascular smooth muscle cell (VSMC) viability and invasion; and microRNA-320b was enriched in exosomes from oxLDL-stimulated macrophages. This study aimed to further explore molecular mechanisms of exosomal microRNA-320b from oxLDL-stimulated macrophages on cellular functions of VSMCs. Exosomes from oxLDL-stimulated macrophages with microRNA-320b mimic/inhibitor transfection were used to treat VSMCs. Next, microRNA-320b mimic/inhibitor, and microRNA-320b mimic with or without peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) overexpression vector were transfected into VSMCs. Viability, invasion, apoptosis, contractile/synthetic phenotype markers, and MEK/ERK pathway were detected in VSMCs. Exosomes from microRNA-320b mimic-treated macrophages promoted viability, invasion, and synthetic phenotype marker osteopontin, while suppressed apoptosis and contractile phenotype marker α-smooth muscle actin in VSMCs. Importantly, direct microRNA-320b mimic treatment aggravated viability, invasion, and synthetic phenotype transition in VSMCs. However, microRNA-320b inhibitor showed the opposite effects as microRNA-320b mimic. Next, luciferase reporter gene assay showed that microRNA-320b directly bound to PPARGC1A; microRNA-320b also inversely regulated PPARGC1A in VSMCs. Moreover, the effect of microRNA-320b mimic on cellular functions of VSMCs was hampered by PPARGC1A overexpression vector (all P < 0.05). Additionally, microRNA-320b activated MEK/ERKT pathway, which was also suppressed by PPARGC1A overexpression vector (all P < 0.05). OxLDL-stimulated macrophages deliver exosomal microRNA-320b to exacerbate viability, invasion, and synthetic phenotype transition in VSMCs via modulating PPARGC1A-mediated MEK/ERK pathway, thus participating in the progression of atherosclerosis.

Colchicine Blocks Abdominal Aortic Aneurysm Development by Maintaining Vascular Smooth Muscle Cell Homeostasis.

Development of non-surgical treatment of human abdominal aortic aneurysm (AAA) has clinical significance. Colchicine emerges as an effective therapeutic regimen in cardiovascular diseases. Yet, whether colchicine slows AAA growth remain controversy. Here, we demonstrated that daily intragastric administration of low-dose colchicine blocked AAA formation, prevented vascular smooth muscle cell (SMC) phenotype switching and apoptosis, and vascular inflammation in both peri-aortic CaPO4 injury and subcutaneous angiotensin-II infusion induced experimental AAA mice models. Mechanistically, colchicine increased global mRNA stability by inhibiting the METTL14/YTHDC1-mediated m6A modification, resulting in increased sclerostin (SOST) expression and consequent inactivation of the WNT/β-catenin signaling pathway in vascular SMCs from mouse AAA lesions and in cultured human aortic SMCs. Moreover, human and mouse AAA lesions all showed increased m6A methylation, decreased SOST expression, and skewed synthetic SMC de-differentiation phenotype, compared to those without AAA. This study uncovers a novel mechanism of colchicine in slowing AAA development by using the METTL14/SOST/WNT/β-catenin axis to control vascular SMC homeostasis in mouse aortic vessels and in human aortic SMCs. Therefore, use of colchicine may benefit AAA patients in clinical practice.

A novel tiRNA-Glu-CTC induces nanoplastics accelerated vascular smooth muscle cell phenotypic switching and vascular injury through mitochondrial damage

Nanoplastics pose several health hazards, especially vascular toxicity. Transfer RNA-derived small RNAs (tsRNAs) are novel noncoding RNAs associated with different pathological processes. However, their biological roles and mechanisms in aberrant vascular smooth muscle cell (VSMC) plasticity and vascular injury are unclear. This study investigated the potent effects of tsRNAs on vascular injury induced by short- and long-term exposure to polystyrene nanoplastics (PS-NPs). Mice were exposed to PS-NPs (100 nm) at different doses (10–100 μg/mL) for 30 or 180 days. High-throughput sequencing was used to analyze tsRNA expression patterns in arterial tissues obtained from an in vivo model. Additionally, quantitative real-time polymerase chain reaction, fluorescent in situ hybridization assays, and dual-luciferase reporter assays were performed to measure the expression and impact of tiRNA-Glu-CTC on VSMCs exposed to PS-NPs. Short-term (≥50 μg/mL, moderate concentration) and long-term (≥10 μg/mL, low concentration) PS-NP exposure induced vascular injury in vivo. Cellular experiments showed that the moderate concentration of PS-NPs induced VSMC phenotypic switching, whereas a high concentration of PS-NPs (100 μg/mL) promoted VSMC apoptosis. PS-NP induced severe mitochondrial damage in VSMCs, including overexpression of reactive oxygen species, accumulation of mutated mtDNA, and dysregulation of genes related to mitochondrial synthesis and division. Compared with the control group, 13 upregulated and 12 downregulated tRNA-derived stress-induced RNAs (tiRNAs) were observed in the long-term PS-NP (50 μg/mL) exposure group. Bioinformatics analysis indicated that differentially expressed tiRNAs targeted genes that were involved in vascular smooth muscle contraction and calcium signaling pathways. Interestingly, tiRNA-Glu-CTC was overexpressed in vivo and in vitro following PS-NP exposure. Functionally, the tiRNA-Glu-CTC inhibitor mitigated VSMC phenotypic switching and mitochondrial damage induced by PS-NP exposure, whereas tiRNA-Glu-CTC mimics had the opposite effect. Mechanistically, tiRNA-Glu-CTC mimics induced VSMC phenotypic switching by downregulating Cacna1f expression. PS-NP exposure promoted VSMC phenotypic switching and vascular injury by targeting the tiRNA-Glu-CTC/Cacna1f axis.

The SNHG12/microRNA-15b-5p/MYLK axis regulates vascular smooth muscle cell phenotype to affect intracranial aneurysm formation

ObjectiveThis research was dedicated to investigating the impact of the SNHG12/microRNA (miR)-15b-5p/MYLK axis on the modulation of vascular smooth muscle cell (VSMC) phenotype and the formation of intracranial aneurysm (IA). MethodsSNHG12, miR-15b-5p and MYLK expression in IA tissue samples from IA patients were tested by RT-qPCR and western blot. Human aortic vascular smooth muscle cells (VSMCs) were cultivated with H2O2 to mimic IA-like conditions in vitro, and the cell proliferation and apoptosis were measured by MTT assay and Annexin V/PI staining. IA mouse models were established by induction with systemic hypertension combined with elastase injection. The blood pressure in the tail artery of mice in each group was assessed and the pathological changes in arterial tissues were observed by HE staining and TUNEL staining. The expression of TNF-α and IL-1β, MCP-1, iNOS, caspase-3, and caspase-9 in the arterial tissues were tested by RT-qPCR and ELISA. The relationship among SNHG12, miR-15b-5p and MYLK was verified by bioinformatics, RIP, RNA pull-down, and luciferase reporter assays. ResultsThe expression levels of MYLK and SNHG12 were down-regulated and that of miR-15b-5p was up-regulated in IA tissues and H2O2-treated human aortic VSMCs. Overexpressed MYLK or SNHG12 mitigated the decrease in proliferation and increase in apoptosis of VSMCs caused by H2O2 induction, and overexpression of miR-15b-5p exacerbated the decrease in proliferation and increase in apoptosis of VSMCs caused by H2O2 induction. Overexpression of miR-15b-5p reversed the H2O2-treated VSMC phenotypic changes caused by SNHG12 up-regulation, and overexpression of MYLK reversed the H2O2-treated VSMC phenotypic changes caused by up-regulation of miR-15b-5p. Overexpression of SNHG12 reduced blood pressure and ameliorated arterial histopathological damage and VSMC apoptosis in IA mice. The mechanical analysis uncovered that SNHG12 acted as an endogenous RNA that competed with miR-15b-5p, thus modulating the suppression of its endogenous target, MYLK. ConclusionDecreased expression of SNHG12 in IA may contribute to the increasing VSMC apoptosis via increasing miR-15b-5p expression and subsequently decreasing MYLK expression. These findings provide potential new strategies for the clinical treatment of IA.

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.

Metabolic changes with the occurrence of atherosclerotic plaques and the effects of statins.

Atherosclerosis is a common cardiovascular disease caused by the abnormal expression of multiple factors and genes influenced by both environmental and genetic factors. The primary manifestation of atherosclerosis is plaque formation, which occurs when inflammatory cells consume excess lipids, affecting their retention and modification within the arterial intima. This triggers endothelial cell (EC) activation, immune cell infiltration, vascular smooth muscle cell (VSMC) proliferation and migration, foam cell formation, lipid streaks, and fibrous plaque development. These processes can lead to vascular wall sclerosis, lumen stenosis, and thrombosis. Immune cells, ECs, and VSMCs in atherosclerotic plaques undergo significant metabolic changes and inflammatory responses. The interaction of cytokines and chemokines secreted by these cells leads to the onset, progression, and regression of atherosclerosis. The regulation of cell- or cytokine-based immune responses is a novel therapeutic approach for atherosclerosis. Statins are currently the primary pharmacological agents utilised for managing unstable plaques owing to their ability to enhance endothelial function, regulate VSMC proliferation and apoptosis by reducing cholesterol levels, and mitigate the expression and activity of inflammatory cytokines. In this review, we provide an overview of the metabolic changes associated with atherosclerosis, describe the effects of inflammatory responses on atherosclerotic plaques, and discuss the mechanisms through which statins contribute to plaque stabilisation. Additionally, we examine the role of statins in combination with other drugs in the management of atherosclerosis.

Selenoprotein deficiency disorder predisposes to aortic aneurysm formation

Aortic aneurysms, which may dissect or rupture acutely and be lethal, can be a part of multisystem disorders that have a heritable basis. We report four patients with deficiency of selenocysteine-containing proteins due to selenocysteine Insertion Sequence Binding Protein 2 (SECISBP2) mutations who show early-onset, progressive, aneurysmal dilatation of the ascending aorta due to cystic medial necrosis. Zebrafish and male mice with global or vascular smooth muscle cell (VSMC)-targeted disruption of Secisbp2 respectively show similar aortopathy. Aortas from patients and animal models exhibit raised cellular reactive oxygen species, oxidative DNA damage and VSMC apoptosis. Antioxidant exposure or chelation of iron prevents oxidative damage in patient’s cells and aortopathy in the zebrafish model. Our observations suggest a key role for oxidative stress and cell death, including via ferroptosis, in mediating aortic degeneration.