Connecting epigenetics and inflammation in vascular senescence: state of the art, biomarkers and senotherapeutics

Vascular diseases pose major health challenges, and understanding their underlying molecular mechanisms is essential to advance therapeutic interventions. Cellular senescence, a hallmark of aging, is a cellular state characterized by cell-cycle arrest, a senescence-associated secretory phenotype macromolecular damage, and metabolic dysregulation. Vascular senescence has been demonstrated to play a key role in different vascular diseases, such as atherosclerosis, peripheral arterial disease, hypertension, stroke, diabetes, chronic venous disease, and venous ulcers. Even though cellular senescence was first described in 1961, significant gaps persist in comprehending the epigenetic mechanisms driving vascular senescence and its subsequent inflammatory response. Through a comprehensive analysis, we aim to elucidate these knowledge gaps by exploring the network of epigenetic alterations that contribute to vascular senescence. In addition, we describe the consequent inflammatory cascades triggered by these epigenetic modifications. Finally, we explore translational applications involving biomarkers of vascular senescence and the emerging field of senotherapy targeting this biological process.

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.

Sarsasapogenin blocks ox-LDL-stimulated vascular smooth muscle cell proliferation, migration, and invasion through suppressing STIM1 expression

Background

Atherosclerosis (AS) is a pathological vascular disorder responsible for the majority of cardiovascular deaths. Sarsasapogenin (Sar) is a natural steroidal compound which has been extensively applied to multiple human diseases due to its pharmacological properties. In the present paper, the impacts of Sar on oxidized low-density lipoprotein (ox-LDL)-treated vascular smooth muscle cells (VSMCs) and its possible action mechanism were investigated.

Methods

Firstly, Cell Counting Kit-8 (CCK-8) estimated the viability of VSMCs following treatment with ascending doses of Sar. Then, VSMCs were treated by ox-LDL to stimulate an in vitro cell model of AS. CCK-8 and 5-Ethynyl-2'-deoxyuridine (EDU) assays were used to assess cell proliferation. Wound healing and transwell assays were applied to measure the migratory and invasive capacities, respectively. The expression of proliferation-, metastasis-, and stromal interaction molecule 1 (STIM1)/Orai signaling-associated proteins was measured by western blot.

Results

The experimental data illuminated that Sar treatment noticeably protected against ox-LDL-elicited VSMCs proliferation, migration, and invasion. Besides, Sar lowered the elevated STIM1 and Orai expression in ox-LDL-treated VSMCs. Further, STIM1 elevation partially abrogated the impacts of Sar on the proliferation, migration, and invasion of VSMCs challenged with ox-LDL.

Conclusions

In conclusion, Sar might reduce STIM1 expression to impede the aggressive phenotypes of ox-LDL-treated VSMCs.

LncRNA RASSF8-AS1 knockdown displayed antiproliferative and proapoptotic effects through miR-188-3p/ATG7 pathway in ox-LDL-treated vascular smooth muscle cells

BACKGROUND

Long noncoding RNA (lncRNA)-mediated changes in gene expression contribute to atherosclerosis (AS) development. However, the roles of numerous lncRNAs in AS have not been fully elucidated. Here, we aimed to investigate the potential role of lncRNA RASSF8-AS1 (RASSF8-AS1) in autophagy of human aortic vascular smooth muscle cells (HA-VSMCs).

METHODS

RASSF8-AS1 expression in patients with AS was extracted from the Gene Expression Omnibus (GEO) database. RASSF8-AS1 and microRNA-188-3p (miR-188-3p) expression was analyzed in 20 enrolled patients with AS. HA-VSMCs were treated with oxidized low-density lipoprotein (ox-LDL) (25, 50, 75, and 100 µg/mL) for 24 h. Loss- or gain-of-function of RASSF8-AS1, miR-1883p, and autophagy-related 7 (ATG7) was studied using the transfected HA-VSMCs. Cell viability was assessed using Cell Counting Kit-8 (CCK-8). Apoptosis was detected with annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI). Relative luciferase reporter assay was used to confirm the targeting relationship of miR-188-3p to RASSF8-AS1 or ATG7. Gene expression was detected by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot.

RESULTS

RASSF8-AS1 was enriched in the serum of patients with AS and ox-LDL-treated HA-VSMCs. Ox-LDL induced proliferation and autophagy while inhibiting the apoptosis of HA-VSMCs, which was abated by RASSF8-AS1 knockdown. RASSF8-AS1 downregulated miR-188-3p of ox-LDL-treated HA-VSMCs. RASSF8-AS1 knockdown caused an increase in miR-188-3p, which inhibited proliferation and autophagy and induced the apoptosis of ox-LDL-treated HA-VSMCs. miR-188-3p inhibited ATG7 expression in ox-LDL-treated HA-VSMCs. RASSF8-AS1 elevated ATG7 and induced autophagy through sponging miR-188-3p in ox-LDL-treated HA-VSMCs.

CONCLUSIONS

RASSF8-AS1 regulated autophagy by targeting miR-188-3p, a messenger RNA-binding miRNA that increases ATG7 level, which may be a new target molecule for the prevention and prognosis of AS.

Regulation of oxidized LDL-induced proliferation and migration in human vascular smooth muscle cells by a novel circ_0007478/miR-638/ROCK2 ceRNA network

BACKGROUND

Circular RNAs (circRNAs) have been implicated in the pathogenesis of atherosclerosis (AS) and the migration and proliferation of vascular smooth muscle cells (VSMCs) under oxidized low-density lipoprotein (ox-LDL). Here, we defined the exact action of human circ_0007478 in VSMC migration and proliferation induced by ox-LDL.

METHODS

Human VSMCs (HVSMCs) were exposed to ox-LDL. Circ_0007478, microRNA (miR)-638, and rho-associated protein kinase 2 (ROCK2) levels were gauged by quantitative real-time PCR (qRT-PCR) and western blot. Cell viability and proliferation were assessed by MTT and EdU assays, respectively. Transwell assays were used to detect cell migration and invasion. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to evaluate the direct relationship between miR-638 and circ_0007478 or ROCK2.

RESULTS

Our data indicated that circ_0007478 expression was augmented in AS serum samples and ox-LDL-treated HVSMCs. Depletion of circ_0007478 attenuated HVSMC proliferation, migration, and invasion induced by ox-LDL. Mechanistically, circ_0007478 targeted miR-638 by directly pairing to miR-638. Reduction of miR-638 reversed the effects of circ_0007478 depletion on ox-LDL-evoked proliferation, migration, and invasion in HVSMCs. ROCK2 was a direct miR-638 target and miR-638-mediated inhibition of ROCK2 relieved ox-LDL-evoked HVSMC proliferation, migration, and invasion. Furthermore, circ_0007478 was identified as a competing endogenous RNA (ceRNA) for miR-638 to modulate ROCK2 expression.

CONCLUSION

Our present study establishes an undescribed ceRNA regulatory network, in which circ_0007478 targets miR-638 to upregulate ROCK2, thereby contributing to ox-LDL-induced proliferation and migration in HVSMCs.

M6A methylation-mediated elevation of SM22α inhibits the proliferation and migration of vascular smooth muscle cells and ameliorates intimal hyperplasia in type 2 diabetes mellitus

Abnormal proliferation of vascular smooth muscle cells (VSMCs) induced by insulin resistance facilitates intimal hyperplasia of type 2 diabetes mellitus (T2DM) and N6-methyladenosine (m⁶A) methylation modification mediates the VSMC proliferation. This study aimed to reveal the m⁶A methylation modification regulatory mechanism. In this study, m⁶A demethylase FTO was elevated in insulin-treated VSMCs and T2DM mice with intimal injury. Functionally, FTO knockdown elevated m⁶A methylation level and further restrained VSMC proliferation and migration induced by insulin. Mechanistically, FTO knockdown elevated Smooth muscle 22 alpha (SM22α) expression and m⁶A-binding protein IGF2BP2 enhanced SM22α mRNA stability by recognizing and binding to m⁶A methylation modified mRNA. In vivo studies confirmed that the elevated m⁶A modification level of SM22α mRNA mitigated intimal hyperplasia in T2DM mice. Conclusively, m⁶A methylation-mediated elevation of SM22α restrained VSMC proliferation and migration and ameliorated intimal hyperplasia in T2DM.

Long non-coding RNA RP11-465L10.10 promotes vascular smooth muscle cells phenotype switching and MMP9 expression via the NF-κB pathway

Background

Thoracic aortic aneurysm/dissection (TAA/D) are complicated vascular disorders with rapid development and high mortality. Vascular smooth muscle cells (VSMCs) phenotype switching plays an important role in the pathological process of TAA/D. Previous studies have indicated a potential correlation between long non-coding RNA (lncRNA) RP11-465L10.10 and matrix metallopeptidase 9 (MMP9) involved in the development of TAA/D. This study aims to investigate the role of lncRNA RP11-465L10.10 in VSMCs phenotype switching and the molecular mechanism in regulating MMP9 expression.

Methods

The expression of RP11-465L10.10 in vascular tissues and in VMSCs was detected by RT-qPCR. To investigate the role of RP11-465L10.10 on VSMCs phenotype switching, an RP11-465L10.10-overexpressed lentiviral vector was constructed and transfected into VSMCs. Through EdU staining, migration assay, flow cytometry analysis, the roles of RP11-465L10.10 were estimated. Bioinformatics indicated that RP11-465L10.10 upregulating MMP9 expression via NF-κB signaling, and SN50 (a specific inhibitor of NF-κB pathway) was used to inhibit the NF-κB pathway activation, then the expression of MMP9 was detected in RP11-465L10.10 overexpressed VMSCs.

Results

In this study, we found RP11-465L10.10 and MMP9 were highly increased in TAD patient tissues, which was consistent in angiotensin II-induced VSMCs phenotype switching. RP11-465L10.10 overexpression facilitated VSMCs phenotype switching and MMP9 expression. Mechanismly, NF-κB signal pathway was involved in RP11-465L10.10 induced VSMCs phenotype switching and MMP9 expression by transcriptome data analysis and experimental confirm.

Conclusion

This study demonstrated that RP11-465L10.10 induces VSMCs phenotype switching and MMP9 expression via the NF-κB signal pathway, suggesting that RP11-465L10.10 might be a potential therapeutic target for TAA/D treatment.

The effects of a biodegradable Mg-based alloy on the function of VSMCs via immunoregulation of macrophages through Mg-induced responses

Background

Restenosis is one of the worst side effects of percutaneous coronary intervention (PCI) due to neointima formation resulting from the excessive proliferation and migration of vascular smooth muscle cells (VSMCs) and continuous inflammation. Biodegradable Mg-based alloy is a promising candidate material because of its good mechanical properties and biocompatibility, and biodegradation of cardiovascular stents. Although studies have shown reduced neointima formation after Mg-based CVS implantation in vivo, these findings were inconsistent with in vitro studies, demonstrating magnesium-mediated promotion of the proliferation and migration of VSMCs. Given the vital role of activated macrophage-driven inflammation in neointima formation, along with the well-demonstrated crosstalk between macrophages and VSMCs, we investigated the interactions of a biodegradable Mg-Nd-Zn-Zr alloy (denoted JDBM), which is especially important for cardiovascular stents, with VSMCs via macrophages.

Methods

JDBM extracts and MgCl₂ solutions were prepared to study their effect on macrophages. To study the effects of the JDBM extracts and MgCl₂ solutions on the function of VSMCs via immunoregulation of macrophages, conditioned media (CM) obtained from macrophages was used to establish a VSMC-macrophage indirect coculture system.

Results

Our results showed that both JDBM extracts and MgCl₂ solutions significantly attenuated the inflammatory response stimulated by lipopolysaccharide (LPS)-activated macrophages and converted macrophages into M2-type cells. In addition, JDBM extracts and MgCl₂ solutions significantly decreased the expression of genes related to VSMC phenotypic switching, migration, and proliferation in macrophages. Furthermore, the proliferation, migration, and proinflammatory phenotypic switching of VSMCs were significantly inhibited when the cells were incubated with CMs from macrophages treated with LPS + extracts or LPS + MgCl₂ solutions.

Conclusions

Taken together, our results suggested that the magnesium in the JDBM extract could affect the functions of VSMCs through macrophage-mediated immunoregulation, inhibiting smooth muscle hyperproliferation to suppress restenosis after implantation of a biodegradable Mg-based stent.

Protective effects of BP-1-102 against intracranial aneurysms-induced impairments in mice

The development of non-invasive pharmacological therapies to prevent the progression and rupture of intracranial aneurysms (IAs) is an important field of research. This study attempts to reveal the role of BP-1-102, an oral bioavailable signal transducer and activator of transcription 3 (STAT3) inhibitor, in IA. We first constructed an IA mouse model by injecting elastase into the cerebrospinal fluid with simultaneous induction of hypertension by deoxycorticosterone acetate (DOCA) implantation. The results showed that the proportion of IA rupture in mice after BP-1-102 administration was significantly reduced, and the survival time was significantly extended. Further research showed that compared with the vehicle group, the proportion of macrophages infiltrated at the aneurysm and the expression of pro-inflammatory cytokines in the BP-1-102 administration group were significantly reduced. The contractile phenotype vascular smooth muscle cell (VSMC) specific markers, SM22α and αSMA, were significantly upregulated in the BP-1-102 group. Furthermore, we found that BP-1-102 inhibited the expression of critical proteins in the nuclear factor kappa-B and Janus kinase 2/STAT3 signalling pathways. Our study shows that BP-1-102 significantly decreases the rupture of IA, reduces the inflammatory responses and modulates the phenotype of VSMCs, suggesting that BP-1-102 could be utilised as a potential intervention drug for IA.

Mass Spectrometry Imaging as a Tool to Investigate Region Specific Lipid Alterations in Symptomatic Human Carotid Atherosclerotic Plaques

Atherosclerosis is characterized by fatty plaques in large and medium sized arteries. Their rupture can causes thrombi, occlusions of downstream vessels and adverse clinical events. The investigation of atherosclerotic plaques is made difficult by their highly heterogeneous nature. Here we propose a spatially resolved approach based on matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging to investigate lipids in specific regions of atherosclerotic plaques. The method was applied to a small dataset including symptomatic and asymptomatic human carotid atherosclerosis plaques. Tissue sections of symptomatic and asymptomatic human carotid atherosclerotic plaques were analyzed by MALDI mass spectrometry imaging (MALDI MSI) of lipids, and adjacent sections analyzed by histology and immunofluorescence. These multimodal datasets were used to compare the lipid profiles of specific histopathological regions within the plaque. The lipid profiles of macrophage-rich regions and intimal vascular smooth muscle cells exhibited the largest changes associated with plaque outcome. Macrophage-rich regions from symptomatic lesions were found to be enriched in sphingomyelins, and intimal vascular smooth muscle cells of symptomatic plaques were enriched in cholesterol and cholesteryl esters. The proposed method enabled the MALDI MSI analysis of specific regions of the atherosclerotic lesion, confirming MALDI MSI as a promising tool for the investigation of histologically heterogeneous atherosclerotic plaques.

Apelin receptor upregulation in spontaneously hypertensive rat contributes to the enhanced vascular smooth muscle cell proliferation by activating autophagy

Background

Proliferation of vascular smooth muscle cells (VSMCs) plays a vital role in the progression of vascular remodeling and hypertension. Apelin-13 promotes VSMC proliferation of normal rats. This study was designed to investigate the roles of apelin receptor (APJ) and apelin-13 in VSMC proliferation of hypertension rats and underlying mechanisms.

Methods

Primary VSMCs were obtained from aorta of Wistar-Kyoto rat (WKY) and spontaneously hypertensive rat (SHR). The expressions of apelin and APJ were detected by Western bolt and PCR, as well as immunohistochemistry. VSMC proliferation was evaluated with CCK-8 kit, PCNA protein expression and percentage of EdU-positive cells. Autophagy was determined by the ratio of LC3BII to LC3BI, ATG5 and p62 protein expressions, as well as LC3B immunofluorescence.

Results

APJ expression was increased while apelin expression was reduced in aorta and VSMCs of SHR compared with those of WKY. Exogenous apelin-13 promoted VSMC proliferation and autophagy of both WKY and SHR, which were prevented by APJ antagonist F13A. Blockade of APJ had no significant effects on VSMC proliferation and autophagy of WKY, but attenuated VSMC proliferation and autophagy of SHR. Administration of autophagy inhibitor 3-methyladenine (3-MA) not only attenuated VSMC proliferation of SHR, but prevented apelin-13-induced VSMC proliferation of both WKY and SHR.

Conclusions

Apelin-13 stimulates VSMC proliferation via APJ-mediated enhancement in autophagy. APJ upregulation in SHR contributes to the enhanced VSMC proliferation.

Regulation of Vascular Calcification by Reactive Oxygen Species

Vascular calcification is the deposition of hydroxyapatite crystals in the medial or intimal layers of arteries that is usually associated with other pathological conditions including but not limited to chronic kidney disease, atherosclerosis and diabetes. Calcification is an active, cell-regulated process involving the phenotype transition of vascular smooth muscle cells (VSMCs) from contractile to osteoblast/chondrocyte-like cells. Diverse triggers and signal transduction pathways have been identified behind vascular calcification. In this review, we focus on the role of reactive oxygen species (ROS) in the osteochondrogenic phenotype switch of VSMCs and subsequent calcification. Vascular calcification is associated with elevated ROS production. Excessive ROS contribute to the activation of certain osteochondrogenic signal transduction pathways, thereby accelerating osteochondrogenic transdifferentiation of VSMCs. Inhibition of ROS production and ROS scavengers and activation of endogenous protective mechanisms are promising therapeutic approaches in the prevention of osteochondrogenic transdifferentiation of VSMCs and subsequent vascular calcification. The present review discusses the formation and actions of excess ROS in different experimental models of calcification, and the potential of ROS-lowering strategies in the prevention of this deleterious condition.

Abnormal expression of homeobox c6 in the atherosclerotic aorta and its effect on proliferation and migration of rat vascular smooth muscle cells

Homeobox c6 (Hoxc6) affects the proliferation, migration, and infiltration of malignant tumor cells; however, the effect of Hoxc6 on atherosclerosis (AS) as well as the proliferation and migration of vascular smooth muscle cells (VSMCs), which play a role in promoting AS, has not yet been well clarified. In the present study, we tested the hypothesis that Hoxc6 affects the proliferation and migration of rat VSMCs, and hence is involved in AS. The results showed that the expression of Hoxc6 mRNA and protein was higher in normal rat aortic wall than in the myocardium. Subsequently, a rat model of AS was established by high-fat feeding for 2 months. The expression of Hoxc6 mRNA and protein was increased significantly in AS lesions, while the expression of p53 protein was decreased and that of proliferating cell nuclear antigen (PCNA) was increased. Moreover, not only the proliferation and mobility of cells in normal culture were decreased, but also the proliferation was stimulated by oxidized low-density lipoprotein, which was decreased after downregulation of Hoxc6 expression in VSMCs in rat. Consecutively, the expression of PCNA protein was decreased, while that of p53 was increased. These results indicated that Hoxc6 is probably involved in AS via p53 and PCNA by affecting the proliferation and migration of VSMCs.

Apoptosis and fibrosis of vascular smooth muscle cells in aortic dissection: an immunohistochemical study

Aortic dissection (AD) is a fatal disease characterized by a ruptured intima that leads to the complete rupture of the aorta. The aim of this study is to examine the immunohistochemical expression of inflammation/fibrosis-associated chemical mediators in AD patients. Surgical specimens of aortic tissues were obtained from 37 patients who underwent an open thoracic aortic repair. AD was detected with histological staining. Local congestion and hemorrhage as well as chronic inflammatory cells infiltrations were observed at the dissection. Moreover, extensive disarrangement and disruption of elastic fibers were observed in the medial layer of the aorta with dissection. In summary, our study revealed that the apoptotic rate of vascular SMCs (VSMCs) in the vascular middle layer is higher in the dissected aortas than in the control aortas, suggesting that abnormally elevated apoptosis is correlated with AD pathogenesis. Functional studies of key genes identified in the apoptotic pathways as well as in extracellular matrix would be critical in thoroughly understanding the underlying mechanisms of AD development. Targeting the mediators related to TGF-β1, the Smad family proteins, and caspase 3 or anti-apoptotic agents may provide diagnostic markers and therapeutic targets that could be used to prevent AD.

The relationship between estrogen-induced phenotypic transformation and proliferation of vascular smooth muscle and hypertensive intracerebral hemorrhage

Background

To explore the effect of estrogen on human cerebral vascular smooth muscle cells (VSMCs) and to clarify the molecular mechanism of estrogen inhibition of VSMC proliferation, which could provide an important reference basis for the clinical treatment of hypertensive intracerebral hemorrhage.

Method

Firstly, the effects of different concentrations of estradiol and estrogen receptor (ESR) blocker (tamoxifen) on the proliferation of human VSMCs and the expression of estrogen-related receptor gene (ESR: ESR1, ESR2, GPER), myocardin (MYOCD), serum reaction factor (SRF), and apoptosis gene caspase-3 were measured to discover the effect and mechanism of tamoxifen on the proliferation and apoptosis of VSMCs. Secondly, the effects of estradiol on human VSMCs treated with angiotensin II (Ang II) were observed by measuring the expression of vascular smooth muscle markers, α-smooth muscle actin (α-SMA), SM22α, FLN, MCP-1, and TLR4.

Results

Estradiol inhibited the proliferation of VSMCs by upregulating the expression of ESR1, ESR2, and GPER and downregulating the expression of caspase-3, MYOCD, and SRF, thereby inhibiting the apoptosis of vascular smooth muscle. At the same time, tamoxifen had opposite effects. Angiotensin II decreased the expression of α-SMA and SM22α and promoted the expression of FLN, MCP-1, and TLR4 protein, while estrogen had the opposite effects.

Conclusions

Estrogen suppresses apoptosis by inhibiting the proliferation of human VSMCs and preventing it from changing from contractile to synthetic. Estrogen can further prevents vascular damage and regulate peripheral inflammatory reaction, thereby producing a protective effect on cardiovascular and cerebrovascular.

miR-137 and its target T-type CaV 3.1 channel modulate dedifferentiation and proliferation of cerebrovascular smooth muscle cells in simulated microgravity rats by regulating calcineurin/NFAT pathway

Objectives

Postflight orthostatic intolerance has been regarded as a major adverse effect after microgravity exposure, in which cerebrovascular adaptation plays a critical role. Our previous finding suggested that dedifferentiation of vascular smooth muscle cells (VSMCs) might be one of the key contributors to cerebrovascular adaptation under simulated microgravity. This study was aimed to confirm this concept and elucidate the underlying mechanisms.

Materials and Methods

Sprague Dawley rats were subjected to 28‐day hindlimb‐unloading to simulate microgravity exposure. VSMC dedifferentiation was evaluated by ultrastructural analysis and contractile/synthetic maker detection. The role of T‐type Ca_V3.1 channel was revealed by assessing its blocking effects. MiR‐137 was identified as the upstream of Ca_V3.1 channel by luciferase assay and investigated by gain/loss‐of‐function approaches. Calcineurin/nuclear factor of activated T lymphocytes (NFAT) pathway, the downstream of Ca_V3.1 channel, was investigated by detecting calcineurin activity and NFAT nuclear translocation.

Results

Simulated microgravity induced the dedifferentiation and proliferation in rat cerebral VSMCs. T‐type Ca_V3.1 channel promoted the dedifferentiation and proliferation of VSMC. MiR‐137 and calcineurin/NFATc3 pathway were the upstream and downstream signalling of T‐type Ca_V3.1 channel in modulating the dedifferentiation and proliferation of VSMCs, respectively.

Conclusions

The present work demonstrated that miR‐137 and its target T‐type Ca_V3.1 channel modulate the dedifferentiation and proliferation of rat cerebral VSMCs under simulated microgravity by regulating calcineurin/NFATc3 pathway.

Cortistatin exerts antiproliferation and antimigration effects in vascular smooth muscle cells stimulated by Ang II through suppressing ERK1/2, p38 MAPK, JNK and ERK5 signaling pathways

Background

Vascular remodeling, that contributes to cardiovascular diseases such as hypertension develops by anomalous proliferation and migration of vascular smooth muscle cells (VSMCs). Cortistatin (CST), a newly discovered biological peptide, has been acknowledged for its protective effects against cardiovascular diseases. Whether CST has an inhibitory regulation role in angiotensin II (Ang II)-induced proliferation and migration of VSMCs and what molecular mechanisms may participate in the CST inhibition process are still unknown.

Methods

VSMCs were divided into control group, Ang II (10^-7 M) group, Ang II + PD98059 (5×10^-5 M) group, Ang II + SB203580 (10^-5 M) group, Ang II + SP600125 (10^-5 M) group, Ang II + XMD17-109 (10^-6 M) group, Ang II + CST (10^-8 M) group and Ang II + CST (10^-7 M) group. Cell proliferation was detected by western blotting and cell counting kit-8 (CCK8) analysis. Migration of VSMCs was measured by Transwell assay.

Results

Compared with control group, Ang II upregulated the expression levels of proliferating cell nuclear antigen (PCNA) and osteopontin (OPN) and downregulated that of α-smooth muscle actin (α-SMA), increased the proliferation rate as shown by CCK8 and VSMC migration as shown by Transwell assay in cultured VSMCs of the Ang II group. Meanwhile, in Ang II-cultured VSMCs, we found activation of extracellular signal-regulated kinase (ERK) 1/2, p38 MAP kinase (p38 MAPK), c-Jun N-terminal kinase (JNK), and ERK5 pathways by western blotting at different time points. However, the proliferation and migration stimulated by Ang II were partly reversed by drug inhibitors of the four pathways, namely, PD98059, SB203580, SP600125 and XMD17-109. When Ang II-stimulated VSMCs were cultured with CST pretreatment, we found that proliferation and migration were greatly suppressed as well as that the ERK1/2, p38 MAPK, JNK and ERK5 pathways were deactivated by CST.

Conclusions

The accumulated data suggest that CST may play a protective role in Ang II-promoted proliferation and migration of VSMCs via inhibiting the mitogen-activated protein kinase (MAPK) family pathways, providing a new orientation of CST in protecting against cardiovascular diseases.

Atorvastatin suppresses vascular hypersensitivity and remodeling induced by transient adventitial administration of lipopolysaccharide in rats

Background

The phenotypic transition of vascular smooth muscle cells (VSMCs) from a contractile to a proliferative state markedly affects the pathophysiology of cardiovascular diseases. The adventitial inflammation can promote neointimal formation and vascular remodeling. We used direct administration of lipopolysaccharide (LPS) into the periphery of the carotid artery to investigate the influence of transient adventitial inflammation on vascular remodeling and its potential mechanism.

Methods

Male 15-week-old Wistar rats were randomly assigned to four groups with six rats in each group. The rats of groups I and II were administered distilled water, and group III and IV were treated with fasudil and atorvastatin respectively. All treatments were given daily for 11 days. On day 8, the adventitia in group I was injected with 5 µL sterile saline, and the group II-IV were injected with 5 µL sterilized LPS. The carotid blood flow and femoral blood pressure were measured in vivo, and the thickness of vascular intima and middle layer was measured in vitro. Serum interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) were determined using enzyme-linked immunosorbent assay (ELISA) assay. And the Rho-associated coiled-coil-containing protein kinase 2 (ROCK2), myosin phosphatase target subunit 1 (MYPT1), myosin light chain (MLC), myocardin, SM-α actin or glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were detected by western blot. The comparisons were made by one-way analysis of variance with Bonferroni's post hoc test. A value of P<0.05 was considered to represent a statistically significant difference.

Results

Transient adventitial inflammation induced by LPS caused no obvious change in basal blood flow, but did lead to vascular hypersensitivity to serotonin. Morphological examinations revealed that the medial layer was the only domain affected, and showed VSMC proliferation and rearrangement. LPS increased serum IL-6 and TNFα contents, ROCK2 expression and activity, and caused changes in the expression levels of some stereotypical VSMC genes. Similar to the Rho-kinase inhibitor fasudil, atorvastatin completely restored the morphological alterations, even increased blood flow.

Conclusions

Our study confirms the beneficial effect of atorvastatin on the vascular system in terms of morphology and function.

The role of microRNAs in the involvement of vascular smooth muscle cells in the development of atherosclerosis

MicroRNAs (miRNAs) are a class of nonprotein-encoding RNAs of ~22 nucleotides in length that bind to or complement each other with a target gene messenger RNA (mRNA) to promote mRNA degradation or inhibit translation of the target mRNA. The protein required [such as Toll-like receptor (TLR) proteins] is controlled at an optimal level. By affecting protein translation, miRNAs have become powerful regulators of biological processes, including development, differentiation, cell proliferation, and apoptosis. MiRNAs are involved in the regulation of proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMCs), thereby affecting the formation of atherosclerosis (AS). In recent years, the role and mechanism of miRNAs involved in AS development in VSMCs have been studied extensively. In the current study, the results and progress in miRNA research are reviewed.

Berberine reduced blood pressure and improved vasodilation in diabetic rats

Hyperglycemia and hypertension are considered to be the two leading risk factors for vascular disease in diabetic patients. However, few pharmacologic agents could provide a combinational therapy for controlling hyperglycemia and hypertension at the same time in diabetes. The objectives of this study are to investigate whether berberine treatment could directly reduce blood pressure and identify the molecular mechanism underlying the vascular protection of berberine in diabetic rats. Berberine was intragastrically administered with different dosages of 50, 100 and 200 mg/kg/day to diabetic rats for 8 weeks since the injection of streptozotocin. The endothelium-dependent/-independent relaxation in middle cerebral arteries was investigated. The activity of large-conductance Ca²⁺-activated K⁺ channel (BK_Ca) was investigated by recording whole-cell currents, analyzing single-channel activities and assessing the expressions of α- and β1-subunit at protein or mRNA levels. Results of the study suggest that chronic administration of 100 mg/kg/day berberine not only lowered blood glucose but also reduced blood pressure and improved vasodilation in diabetic rats. Furthermore, berberine markedly increased the function and expression of BK_Ca β1-subunit in cerebral vascular smooth muscle cells (VSMCs) isolated from diabetic rats or when exposed to hyperglycemia condition. The present study provided initial evidences that berberine reduced blood pressure and improved vasodilation in diabetic rats by activation of BK_Ca channel in VSMCs, which suggested that berberine might provide a combinational therapy for controlling hyperglycemia and blood pressure in diabetes. Furthermore, our work indicated that activation of BK_Ca channel might be the underlying mechanism responsible for the vascular protection of berberine in diabetes.

Human colorectal cancer cells induce vascular smooth muscle cell apoptosis in an exocrine manner

Tumor vessels often lack the smooth muscle layer, and the instability is conducive to tumor invasion and metastasis. The effect of tumor microenvironment on vascular smooth muscle cells needs to be explored. In the present study, we examined the density of the tumor vessels in human colorectal cancer tissues, and used the tumor conditioned medium of human colorectal cancer HT29 cells to mimic the tumor microenvironment. We showed that the vessel density in colorectal cancer tissues increased, which displayed a decreased expression of smooth muscle α-actin, a specific marker of vascular smooth muscle cells and an attenuated or a discontinuous layer of vascular smooth muscle cells compared with the matched normal tissues. We also showed that the tumor conditioned medium decreased the cell viability, and induced the apoptosis in vascular smooth muscle cells in a concentration-dependent manner. The expression of pro-Caspase-3 was down-regulated, accompanied by increasing of cleaved-Caspase-3 in the cells treated with the tumor conditioned medium, suggesting that Caspase-3 was activated. Moreover, the expression of Bax was increased, and the ratio of Bcl-2/Bax was decreased under the same conditions. Furthermore, the treatment with the tumor conditioned medium resulted in loss of mitochondrial membrane potential in vascular smooth muscle cells. These findings suggest that HT29 cells induce apoptosis of vascular smooth muscle cells in an exocrine manner, associated with activating caspase-3 via mitochondrial apoptotic pathway. This may be one of the mechanisms underlying tumor vascular structural abnormalities.

N-(2-Aminoethyl) Ethanolamine-Induced Morphological, Biochemical, and Biophysical Alterations in Vascular Matrix Associated With Dissecting Aortic Aneurysm

Dissecting aortic aneurysm (DAA) is an extended tear in the wall of the aorta along the plane of the vascular media. Our previous studies indicated in a developmental animal model, that DAA was related to pathological alteration in collagen, especially collagen type III. Accordingly, in the present studies, neonatal aortic vascular smooth muscle cells (VSMC) and timed pregnant Sprague-Dawley rat dams were treated with N-(2-aminoethyl) ethanolamine (AEEA), which, as shown previously, causes DAA in offspring. Morphological changes in extracellular matrix (ECM) produced by VSMC in vitro were detailed with scanning electron microscopy (SEM), and biochemical changes in cells and ECM produced by VSMCs were defined by Western blotting. Biophysical changes of the collagen extracted from both the ECM produced by VSMC and extracted from fetal rat aortas were studied with atomic force microscopy (AFM). ECM disruption and irregularities were observed in VSMCs treated with AEEA by SEM. Western blotting showed that collagen type I was much more extractable, accompanied by a decrease of the pellet size after urea buffer extraction in the AEEA-treated VSMC when compared with the control. AFM found that collagen samples extracted from the fetal rat aortas of the AEEA-treated dam, and in the in vitro formed ECM prepared by decellularization, became stiffer, or more brittle, indicating that the 3D organization associated with elasticity was altered by AEEA exposure. Our results show that AEEA causes significant morphological, biochemical, and biomechanical alterations in the ECM. These in vitro and in vivo strategies are advantageous in elucidating the underlying mechanisms of DAA.

Zinc Restored the Decreased Vascular Smooth Muscle Cell Viability under Atherosclerotic Calcification Conditions

Zinc is considered to be involved in maintaining healthy vascular condition. Atherosclerotic calcification of vascular smooth muscle cells (VSMCs) occurs via the mechanism of cell death; therefore, cell viability is a critical factor for preventing VSMC calcification. In this study, we tested whether zinc affected VSMC viability under both normal physiological non-calcifying (0 mM P) and atherosclerotic calcifying conditions (3 and 5 mM P), since VSMC physiological characters change during the VSMC calcification process. The study results showed that an optimal zinc level (15 μM) restored the decreased VSMC viability which was induced under low zinc levels (0 and 1 μM) and calcifying conditions (3 and 5 mM P) at 9 and 15 days culture. This zinc-protecting effect for VSMC viability is more prominent under atherosclerotic calcifying condition (3 and 5 mM P) than normal condition (0 mM P). Also, the increased VSMC viability was consistent with the decreased Ca and P accumulation in VSMC cell layers. The results suggested that zinc could be an effective biomineral for preventing VSMC calcification under atherosclerotic calcifying conditions.