Mindin regulates vascular smooth muscle cell phenotype and prevents neointima formation

Stress, Vascular Smooth Muscle Cell Phenotype and Atherosclerosis: Novel Insight into Smooth Muscle Cell Phenotypic Transition in Atherosclerosis

PURPOSE OF REVIEW

Our work is to establish more distinct association between specific stress and vascular smooth muscle cells (VSMCs) phenotypes to alleviate atherosclerotic plaque burden and delay atherosclerosis (AS) progression.

RECENT FINDING

In recent years, VSMCs phenotypic transition has received significant interests. Different stresses were found to be associated with VSMCs phenotypic transition. However, the explicit correlation between VSMCs phenotype and specific stress has not been elucidated clearly yet. We discover that VSMCs phenotypic transition, which is widely involved in the progression of AS, is associated with specific stress. We discuss approaches targeting stresses to intervene VSMCs phenotypic transition, which may contribute to develop innovative therapies for AS.

LncRNA-LncDACH1 mediated phenotypic switching of smooth muscle cells during neointimal hyperplasia in male arteriovenous fistulas

Arteriovenous fistulas (AVFs) are the most common vascular access points for hemodialysis (HD), but they have a high incidence of postoperative dysfunction, mainly due to excessive neointimal hyperplasia (NIH). Our previous studies have revealed a highly conserved LncRNA-LncDACH1 as an important regulator of cardiomyocyte and fibroblast proliferation. Herein, we find that LncDACH1 regulates NIH in AVF in male mice with conditional knockout of smooth muscle cell-specific LncDACH1 and in male mice model of AVF with LncDACH1 overexpression by adeno-associated virus. Mechanistically, silence of LncDACH1 activates p-AKT through promoting the expression of heat shock protein 90 (HSP90) and serine/arginine-rich splicing factor protein kinase 1 (SRPK1). Moreover, LncDACH1 is transcriptionally activated by transcription factor KLF9 that binds directly to the promoter region of the LncDACH1 gene. In this work, during AVF NIH, LncDACH1 is downregulated by KLF9 and promotes NIH through the HSP90/ SRPK1/ AKT signaling axis.

Extracellular Matrix Interactome in Modulating Vascular Homeostasis and Remodeling

The ECM (extracellular matrix) is a major component of the vascular microenvironment that modulates vascular homeostasis. ECM proteins include collagens, elastin, noncollagen glycoproteins, and proteoglycans/glycosaminoglycans. ECM proteins form complex matrix structures, such as the basal lamina and collagen and elastin fibers, through direct interactions or lysyl oxidase-mediated cross-linking. Moreover, ECM proteins directly interact with cell surface receptors or extracellular secreted molecules, exerting matricellular and matricrine modulation, respectively. In addition, extracellular proteases degrade or cleave matrix proteins, thereby contributing to ECM turnover. These interactions constitute the ECM interactome network, which is essential for maintaining vascular homeostasis and preventing pathological vascular remodeling. The current review mainly focuses on endogenous matrix proteins in blood vessels and discusses the interaction of these matrix proteins with other ECM proteins, cell surface receptors, cytokines, complement and coagulation factors, and their potential roles in maintaining vascular homeostasis and preventing pathological remodeling.

The biological functions and related signaling pathways of SPON2

Spondin-2 (SPON2), also referred to as M-spondin or DIL-1, is a member of the extracellular matrix protein family known as Mindin-F-spondin (FS). SPON2 can be used as a broad-spectrum tumor marker for more than a dozen tumors, mainly prostate cancer. Meanwhile, SPON2 is also a potential biomarker for the diagnosis of certain non-tumor diseases. Additionally, SPON2 plays a pivotal role in regulating tumor metastasis and progression. In normal tissues, SPON2 has a variety of biological functions represented by promoting growth and development and cell proliferation. This paper presents a comprehensive overview of the regulatory mechanisms, diagnostic potential as a broad-spectrum biomarker, diverse biological functions, involvement in various signaling pathways, and clinical applications of SPON2.

Comprehensive analysis of the oncogenic and immunological role of SPON2 in human tumors

BACKGROUND

Sapiens spondin-2 (SPON2) is a protein found in the extracellular matrix that plays a role in a number of processes, including immune reactions and cell adhesion, and is closely linked to the emergence of a number of tumor types. However, we know very little about Sapiens spondin-2. Therefore, we performed a systematic pan-carcinogenic analysis to explore the relationship between Sapiens spondin-2 and cancers.

MATERIALS AND METHODS

By comprehensive use of datasets from TCGA, GEO, GTEx, HPA, CPTAC, GEPIA2, TIMER2, cBioPortal, STRING, we adopted bioinformatics methods to dig up the potential carcinogenesis of SPON2, including dissecting the correlation between SPON2 and gene expression, prognosis, gene mutation, Immunohistochemistry staining, immune cell infiltration, and constructed the interaction network of a total of 54 SPON2-binding proteins as well as explored the enrichment analysis of SPON2-related partners.

RESULTS

The expression of Sapiens spondin-2 in most tumor tissues was higher than that of normal tissues. In addition, SPON2 showed the early diagnostic value in 33 kinds of tumors and was positively or negatively associated with the prognosis of different tumors. It also validates that SPON2 is the gene associated with the majority of immune-infiltrating cells in pan-cancer. High SPON2 expression is associated with tumor progression related pathways.

CONCLUSION

We found and validated the potential use of SPON2 in cancer detection for the first time through pan-cancer analysis. The expression levels of SPON2 in various tumors were quite different from those in normal tissues. Furthermore, the performance of SPON2 in tumorigenesis and tumor immunity verified our hypothesis. At the same time, it has high specificity and sensitivity in cancer detection. Therefore, SPON2 can be employed as an auxiliary index for the initial diagnosis of tumors and a prognostic marker for various types of tumors.

Inhibition of p90RSK Ameliorates PDGF-BB-Mediated Phenotypic Change of Vascular Smooth Muscle Cell and Subsequent Hyperplasia of Neointima

Platelet-derived growth factor type BB (PDGF-BB) regulates vascular smooth muscle cell (VSMC) migration and proliferation, which play critical roles in the development of vascular conditions. p90 ribosomal S6 kinase (p90RSK) can regulate various cellular processes through many different target substrates in several cell types, but the regulatory function of p90RSK on PDGF-BB-mediated cell migration and proliferation and subsequent vascular neointima formation has not yet been extensively examined. In this study, we investigated whether p90RSK inhibition protects VSMCs against PDGF-BB-induced cellular phenotypic changes and the molecular mechanisms underlying the effect of p90RSK inhibition on neointimal hyperplasia in vivo. Pretreatment of cultured primary rat VSMCs with FMK or BI-D1870, which are specific inhibitors of p90RSK, suppressed PDGF-BB-induced phenotypic changes, including migration, proliferation, and extracellular matrix accumulation, in VSMCs. Additionally, FMK and BI-D1870 repressed the PDGF-BB-induced upregulation of cyclin D1 and cyclin-dependent kinase-4 expression. Furthermore, p90RSK inhibition hindered the inhibitory effect of PDGF-BB on Cdk inhibitor p27 expression, indicating that p90RSK may induce VSMC proliferation by regulating the G0/G1 phase. Notably, treatment with FMK resulted in attenuation of neointima development in ligated carotid arteries in mice. The findings imply that p90RSK inhibition mitigates the phenotypic switch and neointimal hyperplasia induced by PDGF-BB.

METTL14/YTHDF1 axis-modified UCHL5 aggravates atherosclerosis by activating the NLRP3 inflammasome

BACKGROUND

Vascular smooth muscle cell (VSMC) phenotypic switching contributes to VSMC proliferation and migration in atherosclerosis (AS). Nevertheless, the regulatory mechanism of VSMC phenotypic switching during AS progression is unclear. Here, the role and regulatory mechanism of UCHL5 in VSMC phenotypic switching during AS progression were investigated.

METHODS

ApoE^-/- mice were fed with high fat diet to establish AS model in vivo. VSMCs stimulated by ox-LDL were used as AS cellular model. VSMC proliferation and migration were examined by CCK8 assay and transwell assay, respectively. The levels of pro-inflammatory cytokines were assessed using ELISA. The interactions between METTL14/YTHDF1, UCHL5 and NLRP3 were analyzed using RIP and/or dual-luciferase reporter gene and/or Co-IP assays. NLRP3 ubiquitination was analyzed by ubiquitination analysis.

RESULTS

UCHL5 was significantly upregulated in AS patients and ox-LDL-treated VSMCs. UCHL5 silencing ameliorated plaque formation and vascular remodeling in vivo and suppressed ox-LDL-induced VSMC proliferation, migration, inflammation and phenotypic switching in vitro. Moreover, METTL14 could increase UCHL5 mRNA m⁶A level and promoted UCHL5 expression by recruiting YTHDF1. Moreover, UCHL5 overexpression enhanced protein stability by deubiquitinating NLRP3. Rescue studies revealed that NLRP3 overexpression abrogated UCHL5 silencing-mediated biological effects in ox-LDL-treated VSMCs.

CONCLUSION

UCHL5 modified by METTL14/YTHDF1 axis could facilitate the inflammation and vascular remodeling in atherosclerosis by activating the NLRP3 inflammasome.

Deficiency of mindin reduces renal injury after ischemia reperfusion

BACKGROUND

Acute renal injury (AKI) secondary to ischemia reperfusion (IR) injury continues to be a significant perioperative problem and there is no effective treatment. Mindin belongs to the mindin/F-spondin family and involves in inflammation, proliferation, and cell apoptosis. Previous studies have explored the biological functions of mindin in liver and brain ischemic injury, but its role in AKI is unknown.

METHOD

To investigate whether mindin has a pathogenic role, mindin knockout (KO) and wild-type (WT) mice were used to establish renal IR model. After 30 min of ischemia and 24 h of reperfusion, renal histology, serum creatinine, and inflammatory response were examined to assess kidney injury. In vitro, proinflammatory factors and inflammatory signaling pathways were measured in mindin overexpression or knockdown and vector cells after hypoxia/reoxygenation (HR).

RESULTS

Following IR, the kidney mindin level was increased in WT mice and deletion of mindin provided significant protection for mice against IR-induced renal injury as manifested by attenuated the elevation of serum creatinine and blood urea nitrogen along with less severity for histological alterations. Mindin deficiency significantly suppressed inflammatory cell infiltration, TNF-α and MCP-1 production following renal IR injury. Mechanistic studies revealed that mindin deficiency inhibits TLR4/JNK/NF-κB signaling activation. In vitro, the expression levels of TNF-α and MCP-1 were increased in mindin overexpression cells compared with vector cells following HR. Moreover, TLR4/JNK/NF-κB signaling activation was elevated in the mindin overexpression cells in response to HR stimulation while mindin knockdown inhibited the activation of TLR4/JNK/ NF-κB signaling after HR in vitro. Further study showed that mindin protein interacted directly with TLR4 protein. And more, mindin protein was confirmed to be expressed massively in renal tubule tissues of human hydronephrosis patients.

CONCLUSION

These data demonstrate that mindin is a critical modulator of renal IR injury through regulating inflammatory responses. TLR4/JNK/NF-κB signaling most likely mediates the biological function of mindin in this model of renal ischemia.

Platelet-derived microvesicles regulate vascular smooth muscle cell energy metabolism via PRKAA after intimal injury

Vascular intimal injury initiates various cardiovascular disease processes. Exposure to subendothelial collagen can cause platelet activation, leading to platelet-derived microvesicles (aPMVs) secretion. In addition, vascular smooth muscle cells (VSMCs) exposed to large amounts of aPMVs undergo abnormal energy metabolism, they proliferate excessively and migrate after the loss of endothelium, eventually contributing to neointimal hyperplasia. However, the roles of aPMVs in VSMC energy metabolism are still unknown. Carotid artery intimal injury model indicated platelets adhered to injured blood vessels. In vitro, p-Pka content was increased in aPMVs. aPMVs significantly changed VSMC glycolysis and oxidative phosphorylation, and promoted VSMC migration and proliferation by upregulating p-PRKAA/p-FoxO1. Compound C, an inhibitor of PRKAA, effectively reversed the cell function and energy metabolism triggered by aPMVs in vitro and neointimal formation in vivo. Our data show that aPMVs can affect VSMC energy metabolism through the Pka/PRKAA/FoxO1 signaling pathway and ultimately affect VSMC function, indicating that VSMC metabolic phenotype shifted by aPMVs can be considered a potential target for the inhibition of hyperplasia and providing a new perspective for regulating the abnormal activity of VSMCs after injury.

Circ_CHFR Promotes Platelet-Derived Growth Factor-BB-Induced Proliferation, Invasion, and Migration in Vascular Smooth Muscle Cells via the miR-149-5p/NRP2 Axis

ABSTRACT

Circular RNA checkpoint with forkhead and ring finger domains (circ_CHFR) were reported to regulate vascular smooth muscle cell (VSMC) dysfunction during atherosclerosis (AS). However, the molecule mechanism of circ_CHFR in AS remains largely unclear. Human VSMCs (HVSMCs) were exposed to platelet-derived growth factor-BB (PDGF-BB) in vitro. Levels of circ_CHFR, microRNA (miR)-149-5p, and neuropilin 2 (NRP2) were determined using quantitative real-time polymerase chain reaction and western blot. Cell proliferation, migration, and invasion were analyzed using cell counting kit-8, colony formation, flow cytometry, wound healing, and transwell assays. The binding interaction between miR-149-5p and circ_CHFR or NRP2 was investigated using the dual-luciferase reporter and RNA immunoprecipitation assays. Circ_CHFR was elevated in PDGF-BB-induced HVSMCs in a dose-independent manner. Silencing of circ_CHFR reversed PDGF-BB-evoked promotion of cell proliferation, migration and invasion, as well as suppression of cell apoptosis in HVSMCs. Mechanistically, circ_CHFR directly bound to miR-149-5p, and miR-149-5p inhibition attenuated the effects of circ_CHFR knockdown on PDGF-BB-induced HVSMCs. Besides, NRP2 was confirmed to be a target of miR-149-5p, and circ_CHFR could regulate NRP2 expression through sponging miR-149-5p. Moreover, miR-149-5p overexpression abolished PDGF-BB-triggered enhancement of cell proliferation, migration, and invasion by targeting NRP2. Circ_CHFR promoted the proliferation, invasion, and migration of PDGF-BB-induced HVSMCs through miR-149-5p/NRP2 axis, providing a new insight into the pathogenesis of AS and a potential therapeutic target for AS treatment.

A new Mfn-2 related synthetic peptide promotes vascular smooth muscle cell apoptosis via regulating the mitochondrial apoptotic pathway by inhibiting Akt signaling

Background

Restenosis after angioplasty is a major challenge for the treatment of coronary artery diseases. Facilitation of vascular smooth muscle cell (VSMC) apoptosis may be an attractive approach to decrease the incidence of restenosis. We synthesized a 16-amino acid mitofusin-2 (Mfn-2) gene related peptide (MRSP) based on the sequence of the p21^ras signature motif, the smallest functional sequence of the Mfn-2 gene with proapoptotic properties in VSMC. We investigated whether MRSP enhanced apoptotic activities to inhibit VSMC accumulation and neointimal hyperplasia in rats with carotid balloon injury.

Methods

VSMCs were treated with different concentrations of MRSP, the PI3K agonist 740 Y-P and the inhibitor LY294002. Cell apoptosis and related pathway molecules were assessed. MRSP was also given to rats with carotid artery balloon injury. Neointimal hyperplasia and cell apoptotic pathways were detected.

Results

In vitro experiments revealed that MRSP treatment significantly increased VSMC apoptosis and induced increases in procaspase-9 cleavage, caspase-3 activation, cytochrome c release from mitochondria to the cytoplasm and the Bax/Bcl-2 ratio but not caspase-8 expression, indicating that the mitochondrial apoptotic cascade was activated by MRSP, which might be attributed to suppression of the PI3K/Akt signaling pathway. We further found that the PI3K agonist 740 Y-P prevented and that the inhibitor LY294002 strengthened the proapoptotic effects of MRSP. MRSP strongly inhibited neointimal hyperplasia and VSMC accumulation, but increased VSMC apoptosis in the vascular wall after balloon injury. Moreover, MRSP substantially enhanced Bax and cleaved caspase-3 expression and decreased Bcl-2 levels in intima, accompanied by decreased levels of phosphorylated Akt and PI3K in vivo.

Conclusions

Taken together, the present study showed that MRSP treatment results in a strong proapoptotic effect by activating the mitochondrial apoptotic cascade through suppression of the PI3K/Akt pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03064-1.

MiR-4787-5p regulates vascular smooth muscle cell apoptosis by targeting PKD1 and inhibiting the PI3K/Akt/FKHR pathway

ABSTRACT

Vascular smooth muscle cell (VSMC) dysfunction is the main cause of aortic dissection (AD). In this study, we focused on the role and mechanism of miR-4787-5p in regulating VSMC apoptosis. RT-qPCR was used to detect the expression of miR-4787-5p in aorta tissues of AD (n=10) and normal aortic tissues of donors (n=10). Cell apoptosis was tested by TUNEL assay and Annexin V FITC/PI staining flow cytometry. The expression of PC1 and the PI3K/Akt/FKHR signaling pathway associated proteins in VSMCs was measured by Western blot. We found that the miR-4787-5p was highly expressed in aorta tissues of AD compared with 10 healthy volunteers. Meanwhile, PI3K/Akt/FKHR signaling pathway was inactive in the aortic tissue of AD. The overexpression of miR-4787-5p significantly induced VSMC apoptosis, and miR-4787-5p knockdown showed the opposite results. In addition, polycystic kidney disease 1 gene (PKD1), which encodes polycystin-1(PC1), was found to be a direct target of miR-4787-5p in the VSMCs and this was validated using a luciferase reporter assay. Overexpression of PC1 by LV-PC1 plasmids markedly eliminated the promotion of miR-4787-5p overexpression on VSMC apoptosis. Finally, it was found that miR-4787-5p deactivated the PI3K/Akt/FKHR pathway, as demonstrated by the down-regulation of phosphorylated (p-)PI3K, p-Akt, and p-FKHR. In conclusion, these findings confirm an important role for the miR-4787-5p/PKD1 axis in AD pathobiology.

Adropin inhibits the phenotypic modulation and proliferation of vascular smooth muscle cells during neointimal hyperplasia by activating the AMPK/ACC signaling pathway

In-stent restenosis (ISR) remains an inevitable problem for some patients receiving drug-eluting stent (DES) implantation. Intimal hyperplasia is an important biological cause of ISR. It has been previously reported that adropin is a potentially protective factor in cardiovascular disease. Therefore, the present study investigated the function of adropin in inhibiting smooth muscle cell (SMC) phenotype modulation and proliferation, causing intimal hyperplasia. A total of 56 patients who visited the hospital consecutively (25 with ISR and 31 without ISR), who were followed up between April 2016 and March 2019, 1 year following DES, were analyzed to evaluate the association between in-stent neointimal volume and adropin serum levels. Rat aorta smooth muscle cells (RASMCs) were used to determine the effects of adropin on their phenotypic modulation and proliferation using western blot, MTT, PCR and immunofluorescence analyses. Adropin serum levels in the ISR group were significantly lower than those in the non-ISR group. Furthermore, linear regression analysis revealed that only adropin levels were negatively associated with neointimal volume in both groups. The overall adropin levels of the 56 patients and the percentages of neointimal volume revealed a strong negative association. In vitro, adropin suppressed angiotensin II (Ang II)-induced phenotypic modulation in RASMCs by restoring variations of osteopontin and α-smooth muscle actin. Furthermore, compared with the Ang II group, adropin markedly decreased the percentage of G₂/M-phase cells. Finally, adropin negatively regulated the phenotypic modulation and proliferation of RASMCs via the AMP-activated protein kinase/acetyl-CoA carboxylase (AMPK/ACC) signaling pathway. In conclusion, an independent, negative association was revealed between adropin and intimal hyperplasia; specifically, adropin inhibited the phenotypic modulation and proliferation of RASMCs by activating the AMPK/ACC signaling pathway. Therefore, adropin may be used as a potential predictor and therapeutic target for intimal hyperplasia and ISR.

Circ_0004872 promotes platelet-derived growth factor-BB-induced proliferation, migration and dedifferentiation in HA-VSMCs via miR-513a-5p/TXNIP axis

The proliferation, migration and dedifferentiation of vascular smooth muscle cells (VSMCs) exert crucial roles in atherosclerosis (AS) progression. The aim of our study was to explore the influences of circular RNA 0004872 (circ_0004872) in platelet-derived growth factor-BB (PDGF-BB)-induced AS cell model and investigate the underlying mechanisms. Real-time quantitative polymerase chain reaction (RT-qPCR) was implemented for the expression detection of circ_0004872, mitogen-activated protein kinase 1 (MAPK1) messenger RNA (mRNA), microRNA-513a-5p (miR-513a-5p) and thioredoxin interacting protein (TXNIP). Cell proliferation was analyzed via Cell Counting Kit 8 (CCK8) assay. Cell migration was assessed via wound healing assay and transwell migration assay. Western blot assay was used to measure the expression of alpha smooth muscle actin (α-SMA), osteopontin (OPN), calponin and TXNIP. Dual-luciferase reporter assay and RNA-pull down assay were used for confirmation of interaction between miR-513a-5p and circ_0004872 or TXNIP. Circ_0004872 expression was elevated in PDGF-BB-induced human aortic vascular smooth muscle cells (HA-VSMCs) and carotid plaque tissues. Circ_0004872 silencing alleviated PDGF-BB-induced proliferation, migration and dedifferentiation in HA-VSMCs. MiR-513a-5p bound to circ_0004872, and circ_0004872 knockdown-induced effects in PDGF-BB-treated HA-VSMCs were largely attenuated by the silencing of miR-513a-5p. MiR-513a-5p bound to the 3' untranslated region (3'UTR) of TXNIP, and miR-513a-5p overexpression-mediated effects were counteracted by the transfection of pcDNA-TXNIP in PDGF-BB-induced HA-VSMCs. TXNIP was modulated by circ_0004872/miR-513a-5p signaling cascade in HA-VSMCs. Circ_0004872 accelerated PDGF-BB-induced proliferation, migration and dedifferentiation in HA-VSMCs through enhancing TXNIP level via sponging miR-513a-5p.

Administration of H2S improves erectile dysfunction by inhibiting phenotypic modulation of corpus cavernosum smooth muscle in bilateral cavernous nerve injury rats

Phenotypic modulation of Corpus Cavernosum Smooth Muscle Cells (CCSMCs) is an important step in the development and progression of bilateral cavernous nerve injury induced erectile dysfunction (BCNI-ED). To investigate the effect of exogenous hydrogen sulfide (H2S) on the phenotypic modulation of CCSMCs in BCNI-ED rats, a total of 18 male Sprague-Dawley rats were equally divided into 3 groups, including sham-operated (Sham) group, BCNI group and BCNI treated with NaHS (BCNI + NaHS) group. The treated group received intraperitoneal injection of NaHS (100 μmol kg-1day-1) for 4 weeks starting day 1 postoperatively. Erectile function was measured by the ratio of intracavernous pressure (ICP)/mean arterial pressure (MAP), and relevant tissues were harvested for Immunohistochemistry, Hematoxylin and eosin (H&E), Masson's trichrome staining, H2S fluorescent probe WSP-1 and Western blot. The primary CCSMCs were isolated and pretreatment with NaHS before exposed to PDGF-BB (platelet-derived growth factor). Relative expression mRNA and protein of phenotypic biomarkers, RhoA, ROCK-1 and cell cycle proteins were detected. Cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (3-MST) and H2S levels in penile tissue was significantly decreased in the BCNI group compared with the Sham group. Compared with the BCNI group, administration of NaHS significantly increased the ratio of ICP/MAP, ratio of smooth muscle to collagen, expressions of a-SMA, calponin and decreased the expression of OPN, collagen-I, RhoA, ROCK1 in the penile tissue. PDGF-BB-treated CCSMCs exhibited higher expression of OPN, RhoA, ROCK1, and lower α-SMA, calponin, which were attenuated by NaHS pretreatment. NaHS suppressed RhoA/ROCK activity and decreased the expression of CDK2, Cyclin E1, while increased the expression of P27kip1 induced by PDGF-BB in CCSMCs. Taken together, this study indicated that exogenous H2S inhibited the phenotypic modulation of CCSMCs by suppressing RhoA/ROCK1 signaling and affecting its downstream factor, CDK2, Cyclin E1, P27kip1, thereby improved BCNI rat erectile function.

Ulinastatin Inhibits the Proliferation, Invasion and Phenotypic Switching of PDGF-BB-Induced VSMCs via Akt/eNOS/NO/cGMP Signaling Pathway

Background

Atherosclerosis is a chronic inflammatory disease responsible for thrombosis, blood supply disorders, myocardial infarction and strokes, eventually leading to increased deaths and reduced quality of life. As inflammation plays a vital role in the development of this disease, the present study aims to investigate whether urinary trypsin inhibitor (UTI) with anti-inflammatory property can inhibit the proliferation, invasion and phenotypic switching of PDGF-BB-induced vascular smooth muscle cells (VSMCs) and probe its potential mechanism.

Methods

Western blot was used to detect the expressions of the proteins related to the Akt/eNOS/NO/cGMP signaling pathway, phenotypic switching and proliferation. CCK-8 assay and EdU staining were used to detect cell proliferation of VSMCs. Transwell and wound healing assays were respectively conducted to measure the invasion and migration of VSMCs. The concentration of NO was evaluated by NO detection kit. ELISA assay analyzed the expression of cyclic GMP (cGMP).

Results

The expressions of p-Akt and p-eNOS were elevated by UTI treatment. Furthermore, UTI inhibited the proliferation, migration and invasion of VSMCs. UTI also increased the expressions of proteins related to phenotypic switching. The amount of NO and expression of cGMP were both elevated under UTI treatment.

Conclusion

UTI inhibits the proliferation, invasion and phenotypic switching of PDGF-BB-induced VSMCs via Akt/eNOS/NO/cGMP signaling pathway, which might provide a theoretical basis for the UTI treatment of atherosclerosis.

Microparticles-Mediated Vascular Inflammation and its Amelioration by Antioxidant Activity of Baicalin

Microparticles (MPs) are extracellular vesicles (0.1–1.0 μm in size), released in response to cell activation or apoptosis. Endothelial microparticles (EC-MP), vascular smooth muscle cell microparticles (VSMC-MP), and macrophage microparticles (MØ-MP) are key hallmarks of atherosclerosis progression. In our current study, we investigated the potent antioxidant activity of baicalin to ameliorate MP-induced vascular smooth muscle cell (VSMC) dysfunction and endothelial cell (EC) dysfunction, as well as the production of inflammatory mediators in macrophage (RAW264.7). In our study, baicalin suppressed the apoptosis, reactive oxygen species (ROS) generation, NO production, foam cell formation, protein expression of inducible nitric oxide synthase and cyclooxygenase-2 in MØ-MP-induced RAW264.7. In addition, VSMC migration induced by VSMC-MP was dose-dependently inhibited by baicalin. Likewise, baicalin inhibits metalloproteinase-9 expression and suppresses VSMC-MP-induced VSMC proliferation by down-regulation of mitogen-activated protein kinase and proliferating cell nuclear antigen protein expressions. Baicalin also inhibited ROS production and apoptosis in VSMC. In EC, the marker of endothelial dysfunction (endothelial senescence, upregulation of ICAM, and ROS production) induced by EC-MP was halted by baicalin. Our results suggested that baicalin exerts potent biological activity to restore the function of EC and VSMC altered by their corresponding microparticles and inhibits the release of inflammation markers from activated macrophages.

Transcriptional Activation of Matricellular Protein Spondin2 (SPON2) by BRG1 in Vascular Endothelial Cells Promotes Macrophage Chemotaxis

The matricellular protein SPON2 plays diverse roles in the development of cardiovascular diseases. SPON2 is expressed in endothelial cells, but its transcription regulation in the context of atherogenesis remains incompletely appreciated. Here we report that SPON2 expression was up-regulated by pro-atherogenic stimuli (oxLDL and TNF-α) in vascular endothelia cells. In addition, endothelial SPON2 was elevated in Apoe^–/– mice fed on a Western diet compared to the control mice. Induction of SPON2 in endothelial cells by pro-atherogenic stimuli was mediated by BRG1, a chromatin remodeling protein, both in vitro and in vivo. Further analysis revealed that BRG1 interacted with the sequence-specific transcription factor Egr-1 to activate SPON2 transcription. BRG1 contributed to SPON2 trans-activation by modulating chromatin structure surrounding the SPON2 promoter. Functionally, activation of SPON2 transcription by the Egr-1/BRG1 complex provided chemoattractive cues for macrophage trafficking. SPON2 depletion abrogated the ability of BRG1 or Egr-1 to stimulate endothelial derived chemoattractive cue for macrophage migration. On the contrary, recombinant SPON2 rescued endothelial chemo-attractability in the absence of BRG1 or Egr-1. In conclusion, our data have identified a novel transcriptional cascade in endothelial cells that may potentially promote macrophage recruitment and vascular inflammation leading to atherogenesis.

Mindin serves as a tumour suppressor gene during colon cancer progression through MAPK/ERK signalling pathway in mice

Mindin is important in broad spectrum of immune responses. On the other hand, we previously reported that mindin attenuated human colon cancer development by blocking angiogenesis through Egr-1-mediated regulation. However, the mice original mindin directly suppressed the syngenic colorectal cancer (CRC) growth in our recent study and we aimed to further define the role of mindin during CRC development in mice. We established the mouse syngeneic CRC CMT93 and CT26 WT cell lines with stable mindin knock-down or overexpression. These cells were also subcutaneously injected into C57BL/6 and BALB/c mice as well as established a colitis-associated colorectal cancer (CAC) mouse model treated with lentiviral-based overexpression and knocked-down of mindin. Furthermore, we generated mindin knockout mice using a CRISPR-Cas9 system with CAC model. Our data showed that overexpression of mindin suppressed cell proliferation in both of CMT93 and CT26 WT colon cancer cell lines, while the silencing of mindin promoted in vitro cell proliferation via the ERK and c-Fos pathways and cell cycle control. Moreover, the overexpression of mindin significantly suppressed in vivo tumour growth in both the subcutaneous transplantation and the AOM/DSS-induced CAC models. Consistently, the silencing of mindin reversed these in vivo observations. Expectedly, the tumour growth was promoted in the CAC model on mindin-deficient mice. Thus, mindin plays a direct tumour suppressive function during colon cancer progression and suggesting that mindin might be exploited as a therapeutic target for CRC.

Role of Extracellular Matrix in Gastrointestinal Cancer-Associated Angiogenesis

Gastrointestinal tumors are responsible for more cancer-related fatalities than any other type of tumors, and colorectal and gastric malignancies account for a large part of these diseases. Thus, there is an urgent need to develop new therapeutic approaches to improve the patients' outcome and the tumor microenvironment is a promising arena for the development of such treatments. In fact, the nature of the microenvironment in the different gastrointestinal tracts may significantly influence not only tumor development but also the therapy response. In particular, an important microenvironmental component and a potential therapeutic target is the vasculature. In this context, the extracellular matrix is a key component exerting an active effect in all the hallmarks of cancer, including angiogenesis. Here, we summarized the current knowledge on the role of extracellular matrix in affecting endothelial cell function and intratumoral vascularization in the context of colorectal and gastric cancer. The extracellular matrix acts both directly on endothelial cells and indirectly through its remodeling and the consequent release of growth factors. We envision that a deeper understanding of the role of extracellular matrix and of its remodeling during cancer progression is of chief importance for the development of new, more efficacious, targeted therapies.

Septin4 Prevents PDGF-BB-induced HAVSMC Phenotypic Transformation, Proliferation and Migration by Promoting SIRT1-STAT3 Deacetylation and Dephosphorylation

SIRT1 and STAT3 are key to human aortic vascular smooth muscle cells (HAVSMCs) proliferation, migration and phenotypic transformation, but the regulatory mechanism of SIRT1-STAT3 in this process is still unclear. Septin4 is a cytoskeleton-related protein that regulates oxidative stress-vascular endothelial injury. However, the role and underlying mechanism of Septin4 in atherosclerosis remains unknown. Here, we revealed the role and mechanism of Septin4 in regulating SIRT1-STAT3 in atherosclerosis. We determined that the expression of Septin4 were markedly increased in Apoe^-/- atherosclerosis mice and PDGF-BB-induced HAVSMCs. Knockdown of Septin4 significantly increased PDGF-BB-induced HAVSMCs proliferation, migration and phenotypic transformation, while overexpression of Septin4 had the opposite effects. Mechanically, co-immunoprecipitation results demonstrated that Septin4 was a novel interacting protein of STAT3 and SIRT1. Septin4 formed a complex with SIRT1-STAT3, enhancing the interaction between SIRT1 and STAT3, ensuing promoting SIRT1-regulated STAT3-K685 deacetylation and STAT3-Y705 dephosphorylation, which inhibited PDGF-BB-induced HAVSMCs proliferation, migration and phenotype transformation. Therefore, our findings provide novel insights into the prevention and treatment of atherosclerosis.

Pterostilbene Attenuates Experimental Atherosclerosis through Restoring Catalase-Mediated Redox Balance in Vascular Smooth Muscle Cells

Atherosclerosis, the major risk of cardiovascular events, is a chronic vascular inflammatory disease. Pterostilbene is a naturally occurring dimethylated analogue of resveratrol and has recently been demonstrated to be beneficial against cardiovascular diseases. However, the underlying mechanisms of pterostilbene on atherosclerosis remain elusive. Experimental atherosclerosis was induced by a high-fat diet (HFD) in apolipoprotein E knockout (ApoE^-/-) mice. Pterostilbene was administered intragastrically for 16 weeks. We found that pterostilbene significantly attenuated thoracic and abdominal atherosclerotic plaque formation in HFD-fed ApoE^-/-mice, accompanied by modulated lipid profiles and reduced production of proinflammatory cytokines (including IL-6, IFN-γ, and TNF-α). In addition, pterostilbene restored vascular redox balance in thoracic and abdominal aorta, evidenced by enhanced catalase (CAT) expression and activities, and decreased malondialdehyde and H₂O₂ production. Notably, pterostilbene specifically induced CAT expression and activities in the vascular smooth muscle cells (VSMCs) of thoracic and abdominal aorta. In vitro, pterostilbene markedly promoted the expression and activity of CAT and decreased ox-low-density lipoprotein (LDL)-mediated VSMC proliferation and intracellular H₂O₂ production, which was abolished by CAT siRNA knockdown or inhibition. Pterostilbene-induced CAT expression was associated with inhibition of Akt, PRAS40, and GSK-3β signaling activation and upregulation of PTEN. Our data clearly demonstrated that pterostilbene exerted an antiatherosclerotic effect by inducing CAT and modulating the VSMC function.

Angiotensin II Receptor Type 1 Antagonists Modulate Vascular Smooth Muscle Cell Proliferation and Migration via AMPK/mTOR

The aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) in the vascular wall are crucial pathological events involved in cardiovascular impairments including hypertension, heart failure, and atherosclerosis. At the molecular level, the mammalian target of rapamycin (mTOR)-ribosomal protein S6 kinase beta-1 (p70S6K) signaling pathway is essential to potentiate VSMC proliferation and migration. Although angiotensin II receptor type 1 -(AT1-R) antagonists such as valsartan and telmisartan have a significant cardiovascular protective effect, the molecular basis of this class of drugs in VSMC proliferation and migration remains elusive. By using cultured VSMCs, adenosine monophosphate-activated protein kinase (AMPK) α2 knockout mice, and hypertensive rat models, this study investigated whether AT1-R antagonists can inhibit the mTOR-p70S6K signaling pathway in VSMCs and the vascular wall. Valsartan activated AMPK, which in turn suppressed reactive oxygen species production and consequently attenuated VSMC proliferation and migration. In vivo, a clinical dose of telmisartan significantly inhibited the mTOR-p70S6K signaling pathway in the vascular wall of wild-type but not AMPKα2-/- mice. Furthermore, spontaneously hypertensive rats had significantly elevated phosphorylation of mTOR and p70S6K in the aorta compared to Wistar-Kyoto rats, which were reduced by telmisartan administration. These data suggest that AT1-R antagonists inhibit VSMC proliferation and migration via their regulation of AMPK, mTOR, and p70S6K, which contribute to the cardioprotective effects of these drugs.

CKLF1 aggravates neointimal hyperplasia by inhibiting apoptosis of vascular smooth muscle cells through PI3K/AKT/NF-κB signaling

Chemokine-like factor 1 (CKLF1) is a cytokine, which has a detrimental effect on the multiple disease progression. Our previous studies reported that arterial injury induced the upregulation of CKLF1 expression in artery at 7-14 days after injury. Here, using a rat carotid balloon injury model, we found that CKLF1 knockdown in the injured site abolished neointimal formation and even decreased medial area; contrarily, CKLF1 overexpression developed a thicker neointima than controls, demonstrating that CKLF1 exerted positive effects on neointimal hyperplasia and the accumulation of vascular smooth muscle cells (VSMC). The mechanism study indicated that CKLF1 reduced susceptibility to the cell cycle G2/M arrest and apoptosis, and thereby speeding up VSMC accumulation. This role of CKLF1 was tightly associated with phosphatidylinositol (PI) 3-kinase signaling pathway. CKLF1 increased the expression of four isoforms of the PI3-kinase catalytic subunits, which in turn activated its downstream targets Akt and an effector NF-κB accepted as critical transcription factors of cell survival and proliferation. Furthermore, RNA-sequencing analysis revealed that CKLF1 had wide-ranging roles in regulating the expression of genes that mainly engaged in cell apoptosis and innate immune response. Collectively, the data allow us to conclude that high level CKLF1 after artery injury switches the balance of VSMC proliferation and apoptosis through PI3K/AKT/NF-κB signaling and consequently leads to neointimal hyperplasia. The findings shed insight into new treatment strategies to limit restenosis based on CKLF1 as a future target.

Genome-wide association study identifies loci for arterial stiffness index in 127,121 UK Biobank participants

Arterial stiffness index (ASI) is a non-invasive measure of arterial stiffness using infra-red finger sensors (photoplethysmography). It is a well-suited measure for large populations as it is relatively inexpensive to perform, and data can be acquired within seconds. These features raise interest in using ASI as a tool to estimate cardiovascular disease risk as prior work demonstrates increased arterial stiffness is associated with elevated systolic blood pressure, and ASI is predictive of cardiovascular disease and mortality. We conducted genome-wide association studies (GWASs) for ASI in 127,121 UK Biobank participants of European-ancestry. Our primary analyses identified variants at four loci reaching genome-wide significance (P < 5 × 10^-8): TEX41 (rs1006923; P = 5.3 × 10^-12), FOXO1 (rs7331212; P = 2.2 × 10^-11), C1orf21 (rs1930290, P = 1.1 × 10^-8) and MRVI1 (rs10840457, P = 3.4 × 10^-8). Gene-based testing revealed three significant genes, the most significant gene was COL4A2 (P = 1.41 × 10^-8) encoding type IV collagen. Other candidate genes at associated loci were also involved in smooth muscle tone regulation. Our findings provide new information for understanding the development of arterial stiffness.

Calcified decellularized arterial scaffolds impact vascular smooth muscle cell transformation via downregulating α-SMA expression and upregulating OPN expression

The underlying mechanisms of arterial remodeling (AR) remain unclear. Studies have indicated that decellularized scaffolds stimulate the differentiation of fibroblasts into myofibroblasts and promote the accumulation of the extracellular matrix (ECM). In the present study, the impact of ECM changes following AR on vascular smooth muscle cell (VSMC) phenotypes was investigated. VSMCs were co-cultured with normal or calcified decellularized arterial scaffolds. The expression levels of α-smooth muscle actin (α-SMA) and osteopontin (OPN) were measured at 2, 5, 10, 15 and 21 days following the establishment of the co-culture systems. The expression of α-SMA in the normal co-culture group was significantly increased compared with that in the calcified arterial decellularized scaffold co-culture group (P<0.05 and P<0.001). In addition, the expression of OPN in the AR co-culture group was significantly increased compared with the normal co-culture group (P<0.05 and P<0.001). To conclude, the calcified decellularized arterial scaffolds impact VSMC transformation by downregulating α-SMA expression and upregulating OPN expression (P<0.001). To the best of our knowledge, the present study is the first study that co-cultured VSMCs with normal or calcified decellularized arterial scaffolds.

Downregulation of the transcriptional co-activator PCAF inhibits the proliferation and migration of vascular smooth muscle cells and attenuates NF-κB-mediated inflammatory responses

P300/CBP-associated factor (PCAF) regulates vascular inflammation. This study was to explore the effect of PCAF on the proliferation and migrationof vascular smooth muscle cells (VSMCs) and neointimal hyperplasia in balloon-injured rat carotid artery. Downregulation of PCAF remarkably suppressed VSMCs proliferation and migration induced by lipopolysaccharide, and also significantly inhibit the nuclear translocation of nuclear factor-kappaB p65. Meanwhile, downregulation of PCAF inhibited the mRNA expression of tumor necrosis factor-α and interleukin-6, and also the levels in culture supernatants. Moreover, downregulation of PCAF profoundly reduced the intima area and the ratio of intima area to media area in balloon-injured rat carotid artery. In addition, the expression of PCNA and NF-κB p65 in intima were decreased by downregulation of PCAF. These results highlight that PCAF may be a potential target for prevention and treatment of neointimal hyperplasia and restenosis after angioplasty.

Epac1 deficiency inhibits basic fibroblast growth factor-mediated vascular smooth muscle cell migration

Vascular smooth muscle cell (VSMC) migration and the subsequent intimal thickening play roles in vascular restenosis. We previously reported that an exchange protein activated by cAMP 1 (Epac1) promotes platelet-derived growth factor (PDGF)-induced VSMC migration and intimal thickening. Because basic fibroblast growth factor (bFGF) also plays a pivotal role in restenosis, we examined whether Epac1 was involved in bFGF-mediated VSMC migration. bFGF-induced lamellipodia formation and migration were significantly decreased in VSMCs obtained from Epac1-/- mice compared to those in Epac1+/+-VSMCs. The bFGF-induced phosphorylation of Akt and glycogen synthase kinase 3β (GSK3β), which play a role in bFGF-induced cell migration, was attenuated in Epac1-/--VSMCs. Intimal thickening induced by the insertion of a large wire was attenuated in Epac1-/- mice, and was accompanied by the decreased phosphorylation of GSK3β. These data suggest that Epac1 deficiency attenuates bFGF-induced VSMC migration, possibly via Akt/GSK3β pathways.

Relation of serum spondin-2 levels with cardiac morphology and inflammatory parameters in hemodialysis patients

PURPOSE

Cardiovascular diseases are the leading causes of mortality in chronic kidney disease. Spondin-2 (SP-2), an intrinsic cardio-protective factor, prevents maladaptive remodeling. We aimed to determine the relation between serum SP-2 levels and cardiac morphology along with inflammatory parameters in hemodialysis (HD) patients.

METHOD

The study comprised a total of 95 patients (61 females) receiving HD treatment three times a week for at least 6 months, and a control group consisting of age and gender matched 62 subjects (34 females). SP-2 levels were determined by ELISA. Echocardiography, 24-h ambulatory blood pressure monitoring, and carotid artery intima-media thickness (CIMT) measurement were performed in all subjects. The relation of serum SP-2 levels with CIMT, echocardiographic parameters, CRP, and absolute neutrophil-to-lymphocyte count ratio (NLR) was evaluated by correlation analysis.

RESULTS

SP-2 levels were found to be significantly higher in the HD group than the control group (16.660 [8.719-20.938] vs. 3.988 [2.702-8.042] ng/L; P < 0.001). CIMT, CRP, and NLR were also higher in HD group (P < 0.005, P < 0.001, and P < 0.001, respectively). Significantly positive correlation was found between SP-2 and left ventricular mass, left ventricular mass index, CRP, and NLR, but no correlation was determined between SP-2 and CIMT. SP-2 was not statistically significant variable for the determination of LVH in univariate logistic regression analysis [Wald = 2.375; OR (95% CI) = 1.000 (0.999-1.000), P = 0.123].

CONCLUSION

Serum SP-2 levels were higher in HD patients compared to the population with normal renal functions. The results suggest that SP-2, an uremic toxin, might be effective over a complex pathway in the inflammatory process and in the pathogenesis of cardiovascular diseases of patients under HD treatment.

Isolation and differential transcriptome of vascular smooth muscle cells and mid-capillary pericytes from the rat brain

Brain mural cells form a heterogeneous family which significantly contributes to the maintenance of the blood-brain barrier and regulation of the cerebral blood flow. Current procedures to isolate them cannot specifically separate their distinct subtypes, in particular vascular smooth muscle cells (VSMCs) and mid-capillary pericytes (mcPCs), which differ among others by their expression of smooth muscle actin (SMA). We herein describe an innovative method allowing SMA⁺ VSMCs and SMA⁻ mcPCs to be freshly isolated from the rat cerebral cortex. Using differential RNA-Seq analysis, we then reveal the specific gene expression profile of each subtype. Our results refine the current description of the role of VSMCs in parenchymal cortical arterioles at the molecular level and provide a unique platform to identify the molecular mechanisms underlying the specific functions of mcPCs in the brain vasculature.

'Blow my mind(in)' - mindin neutralization for the prevention of atherosclerosis?

The hallmark features of atherosclerosis include accumulation of low-density lipoprotein (LDL) carrying cholesterol in the vessel wall, formation of lipid-laden foam cells, and the creation of a pro-inflammatory microenvironment. To date, no effective treatments are clinically available for increasing cholesterol efflux from vascular macrophages and inducing reverse cholesterol transport (RCT). In an article published recently in Clinical Science (vol 132, issue 6, 1199-1213), Zhang and colleagues identified the extracellular matrix protein mindin/spondin 2 as a positive regulator of atherosclerosis. Genetic knockout of mindin in apolipoprotein-E (apoE)^-/- mice attenuated atherosclerosis, foam cell formation, and inflammation within the vessel wall. Conversely, selective overexpression of mindin in macrophages in apoE^-/- mice was sufficient to promote the greater severity of atherosclerosis. Interestingly, foam cell formation was closely associated with the expression of cholesterol transporters (ABCA1 and ACBG1) that facilitate cholesterol efflux. Liver X receptor (LXR)-β is a key modulator of cholesterol transporter expression and formed direct interactions with mindin. Furthermore, the protective effects of mindin deficiency on foam cell formation were blocked by inhibition of LXR-β. This article highlights a novel role of mindin in modulating foam cell formation and atherosclerosis development in mice through direct regulation of LXR-β. Thus far, direct targetting of LXR-β via pharmacological agonists has proven to be problematic due to the lack of subtype selective inhibitors and associated adverse effects. Indirect targetting of LXR-β, therefore, via mindin inhibition offers a new therapeutic strategy for increasing LXR-β induced cholesterol efflux, reducing foam cell formation, and preventing or treating atherosclerosis.

Mindin deficiency in macrophages protects against foam cell formation and atherosclerosis by targeting LXR-β

Mindin, which is a highly conserved extracellular matrix protein, has been documented to play pivotal roles in regulating angiogenesis, inflammatory processes, and immune responses. The aim of the present study was to assess whether mindin contributes to the development of atherosclerosis. A significant up-regulation of Mindin expression was observed in the serum, arteries and atheromatous plaques of ApoE−/− mice after high-fat diet treatment. Mindin−/−ApoE−/− mice and macrophage-specific mindin overexpression in ApoE−/− mice (Lyz2-mindin-TG) were generated to evaluate the effect of mindin on the development of atherosclerosis. The Mindin−/−ApoE−/− mice exhibited significantly ameliorated atherosclerotic burdens in the entire aorta and aortic root and increased atherosclerotic plaque stability. Moreover, bone marrow transplantation further demonstrated that mindin deficiency in macrophages was largely responsible for the alleviated atherogenesis. The Lyz2-mindin-TG mice exhibited the opposite phenotype. Mindin deficiency enhanced foam cell formation by increasing the expression of cholesterol effectors, including ABCA1 and ABCG1. The mechanistic study indicated that mindin ablation promoted LXR-β expression via a direct interaction. Importantly, LXR-β inhibition largely reversed the ameliorating effect of mindin deficiency on foam cell formation and ABCA1 and ABCG1 expression. The present study demonstrated that mindin deficiency serves as a novel mediator that protects against foam cell formation and atherosclerosis by directly interacting with LXR-β.

VEGF and VEGFB Play Balancing Roles in Adipose Differentiation, Gene Expression, and Function

Obesity is the result of abnormal adipose development and energy metabolism. Using vascular endothelial growth factor (VEGF) B-knockout and inducible VEGF downregulation mouse models, we have shown that VEGFB inactivation caused expansion of white adipose, whitening of brown adipose, an increase in fat accumulation, and a reduction in energy consumption. At the same time, expression of the white adipose-associated genes was increased and brown adipose-associated genes decreased. VEGF repression, in contrast, induced brown adipose expansion and brown adipocyte development in white adipose, increased energy expenditure, upregulated brown adipose-associated genes, and downregulated white adipose-associated genes. When VEGFB-knockout and VEGF-repressed mice are crossed together, VEGF and VEGFB can counteractively regulate large numbers of genes and efficiently reverse each other's roles. These genes, under counteractive VEGF and VEGFB regulations, include transcription factors, adhesion molecules, and metabolic enzymes. This balancing role is confirmed by morphologic and functional changes. This study reports that VEGF and VEGFB counteractively regulate adipose development and function in energy metabolism.

Hypoxia-inducible factor 1a induces phenotype switch of human aortic vascular smooth muscle cell through PI3K/AKT/AEG-1 signaling

To date, hypoxia-inducible factor 1a (HIF-1a) and astrocyte elevated gene-1 (AEG-1) have been involved in the proliferation, migration and morphological changes of vascular smooth muscle cells. However, the potential relationship of HIF-1a-AEG-1 pathway in human aortic smooth muscle cell (HASMC) has not been reported. In the present study, in-vitro assays were utilized to explore the potential impact of HIF-1a-AEG-1 signaling on HASMC phenotype. Here, we found that HIF-1a expression was up-regulated in the media of thoracic aortic dissection tissues as compared with normal aortic tissues, and was associated with increased apoptotic SMCs and decreased AEG-1 expression. Mechanically, hypoxia promoted the expression of HIF-1a by PI3K-AKT pathway in HASMCs; HIF-1a further suppressed the expressions of AEG-1, a-SMA and SM22a, and promoted osteopontin (OPN) expression. Functionally, HIF-1a inhibited the proliferation and migration of HASMCs. However, si-HIF-1a or Akt inhibitor abrogated HIF-1a-mediated related expressions and biological effects above. In conclusion, HIF-1a induces HASMC phenotype switch, and closely related to PI3K/AKT and AEG-1 signaling, which may provide new avenues for the prevention and treatment of aortic dissection diseases.

Update on Vascular Cognitive Impairment Associated with Subcortical Small-Vessel Disease

Subcortical small-vessel disease (SSVD) is a disorder well characterized from the clinical, imaging, and neuropathological viewpoints. SSVD is considered the most prevalent ischemic brain disorder, increasing in frequency with age. Vascular risk factors include hypertension, diabetes, hyperlipidemia, elevated homocysteine, and obstructive sleep apnea. Ischemic white matter lesions are the hallmark of SSVD; other pathological lesions include arteriolosclerosis, dilatation of perivascular spaces, venous collagenosis, cerebral amyloid angiopathy, microbleeds, microinfarcts, lacunes, and large infarcts. The pathogenesis of SSVD is incompletely understood but includes endothelial changes and blood-brain barrier alterations involving metalloproteinases, vascular endothelial growth factors, angiotensin II, mindin/spondin, and the mammalian target of rapamycin pathway. Metabolic and genetic conditions may also play a role but hitherto there are few conclusive studies. Clinical diagnosis of SSVD includes early executive dysfunction manifested by impaired capacity to use complex information, to formulate strategies, and to exercise self-control. In comparison with Alzheimer's disease (AD), patients with SSVD show less pronounced episodic memory deficits. Brain imaging has advanced substantially the diagnostic tools for SSVD. With the exception of cortical microinfarcts, all other lesions are well visualized with MRI. Diagnostic biomarkers that separate AD from SSVD include reduction of cerebrospinal fluid amyloid-β (Aβ)42 and of the ratio Aβ42/Aβ40 often with increased total tau levels. However, better markers of small-vessel function of intracerebral blood vessels are needed. The treatment of SSVD remains unsatisfactory other than control of vascular risk factors. There is an urgent need of finding targets to slow down and potentially halt the progression of this prevalent, but often unrecognized, disorder.

Chicoric acid prevents PDGF-BB-induced VSMC dedifferentiation, proliferation and migration by suppressing ROS/NFκB/mTOR/P70S6K signaling cascade

Phenotypic switch of vascular smooth muscle cells (VSMCs) is characterized by increased expressions of VSMC synthetic markers and decreased levels of VSMC contractile markers, which is an important step for VSMC proliferation and migration during the development and progression of cardiovascular diseases including atherosclerosis. Chicoric acid (CA) is identified to exert powerful cardiovascular protective effects. However, little is known about the effects of CA on VSMC biology. Herein, in cultured VSMCs, we showed that pretreatment with CA dose-dependently suppressed platelet-derived growth factor type BB (PDGF-BB)-induced VSMC phenotypic alteration, proliferation and migration. Mechanistically, PDGF-BB-treated VSMCs exhibited higher mammalian target of rapamycin (mTOR) and P70S6K phosphorylation, which was attenuated by CA pretreatment, diphenyleneiodonium chloride (DPI), reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC) and nuclear factor-κB (NFκB) inhibitor Bay117082. PDGF-BB-triggered ROS production and p65-NFκB activation were inhibited by CA. In addition, both NAC and DPI abolished PDGF-BB-evoked p65-NFκB nuclear translocation, phosphorylation and degradation of Inhibitor κBα (IκBα). Of note, blockade of ROS/NFκB/mTOR/P70S6K signaling cascade prevented PDGF-BB-evoked VSMC phenotypic transformation, proliferation and migration. CA treatment prevented intimal hyperplasia and vascular remodeling in rat models of carotid artery ligation in vivo. These results suggest that CA impedes PDGF-BB-induced VSMC phenotypic switching, proliferation, migration and neointima formation via inhibition of ROS/NFκB/mTOR/P70S6K signaling cascade.

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Chicoric acid attenuated PDGF-BB-evoked VSMC phenotypic transformation, proliferation and migration.

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Chicoric acid antagonized the activated ROS/NFκB/mTOR/P70S6K signaling pathway in VSMCs.

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Chicoric acid treatment prevented intimal hyperplasia in rat models of carotid artery ligation.

Interferon Regulatory Factor 4 Inhibits Neointima Formation by Engaging Krüppel-Like Factor 4 Signaling

Background:

The mechanisms underlying neointima formation remain unclear. Interferon regulatory factors (IRFs), which are key innate immune regulators, play important roles in cardiometabolic diseases. However, the function of IRF4 in arterial restenosis is unknown.

Methods:

IRF4 expression was first detected in human and mouse restenotic arteries. Then, the effects of IRF4 on neointima formation were evaluated with universal IRF4-deficient mouse and rat carotid artery injury models. We performed immunostaining to identify IRF4-expressing cells in the lesions. Smooth muscle cell (SMC)–specific IRF4-knockout (KO) and -transgenic (TG) mice were generated to evaluate the effects of SMC-IRF4 on neointima formation. We used microarray, bioinformatics analysis, and chromatin immunoprecipitation assay to identify the downstream signals of IRF4 and to verify the targets in vitro. We compared SMC-IRF4-KO/Krüppel-like factor 4 (KLF4)–TG mice with SMC-IRF4-KO mice and SMC-specific IRF4-TG/KLF4-KO mice with SMC-specific IRF4-TG mice to investigate whether the effect of IRF4 on neointima formation is KLF4-dependent. The effect of IRF4 on SMC phenotype switching was also evaluated.

Results:

IRF4 expression in both the human and mouse restenotic arteries is eventually downregulated. Universal IRF4 ablation potentiates neointima formation in both mice and rats. Immunostaining indicated that IRF4 was expressed primarily in SMCs in restenotic arteries. After injury, SMC-IRF4-KO mice developed a thicker neointima than control mice. This change was accompanied by increased SMC proliferation and migration. However, SMC-specific IRF4-TG mice exhibited the opposite phenotype, demonstrating that IRF4 exerts protective effects against neointima formation. The mechanistic study indicated that IRF4 promotes KLF4 expression by directly binding to its promoter. Genetic overexpression of KLF4 in SMCs largely reversed the neointima-promoting effect of IRF4 ablation, whereas ablation of KLF4 abolished the protective function of IRF4, indicating that the protective effects of IRF4 against neointima formation are KLF4-dependent. In addition, IRF4 promoted SMC dedifferentiation.

Conclusions:

IRF4 protects arteries against neointima formation by promoting the expression of KLF4 by directly binding to its promoter. Our findings suggest that this previously undiscovered IRF4-KLF4 axis plays a key role in vasculoproliferative pathology and may be a promising therapeutic target for the treatment of arterial restenosis.

The extracellular matrix protein mindin attenuates colon cancer progression by blocking angiogenesis via Egr-1-mediated regulation

Mindin, a secreted, highly conserved extracellular matrix (ECM) protein, exerts a broad spectrum of effects on the innate immune system. However, its function in colorectal cancer (CRC) progression is not well established, and its upstream regulation mechanisms remain unclear. Contrary to previous reports, this study used two different enzyme-linked immunosorbent assay (ELISA) kits to show that the serum level of mindin was significantly decreased in CRC patients and that this decreased level is more significantly associated with the early stages of the disease. To explore the regulation of mindin, we used a bioinformatics approach to predict potential transcription factors and determined that early growth response factor (Egr)-1 directly regulates mindin expression at the transcriptional level using dual luciferase, chromatin immunoprecipitation (ChIP) DNA and electrophoretic mobility shift assay (EMSA) methods. Egr-1 regulates mindin mRNA and protein expression in CRC cells, and the protein expression of both Egr-1 and mindin was significantly decreased in tumor lesions of patients compared with adjacent control tissues. Mindin is essential for Egr-1-mediated inhibition of endothelial cell tube formation, and mindin inhibits endotheliocyte proliferation, migration and angiogenic sprouts in vitro. Overexpression of mindin suppressed xenograft tumor growth by blocking angiogenesis instead of directly suppressing CRC cell proliferation. Mechanically, mindin inhibits the hypoxia-induced HIF-1a and VEGFA protein expression in CRC cells and the phosphorylation of VEGFR-2 in endothelial cells. The results suggest that the serum level of mindin can be used as a novel biomarker for early detection of CRC and that the Egr-1/mindin axis is a potential therapeutic target for the inhibition of angiogenesis in CRC development.

Intermedin reduces neointima formation by regulating vascular smooth muscle cell phenotype via cAMP/PKA pathway

BACKGROUND AND AIMS

Vascular smooth muscle cell (VSMC) dedifferentiation contributes to neointima formation, which results in various vascular disorders. Intermedin (IMD), a cardiovascular paracrine/autocrine polypeptide, is involved in maintaining circulatory homeostasis. However, whether IMD protects against neointima formation remains largely unknown. The purpose of this study is to investigate the role of IMD in neointima formation and the possible mechanism.

METHODS

IMD_1-53 (100ng/kg/h) or saline water was used on rat carotid-artery balloon-injury model. The mouse left common carotid-artery ligation-injury model was established using IMD-transgenic and C57BL/6J mice. Immunohistochemistry and immunofluorescence staining was used to detect the protein expression in rat carotid arteries. Radioimmunoassay was used to determine the serum IMD level. The hematoxylin andeosin staining was used for carotid arteries morphological testing. In vitro, for rat primary cultured VSMC phenotype transition, proliferation and migration assays, platelet-derived growth factor-BB (PDGF-BB) reagent and IMD_1-53 peptide were added to the culture media at the final concentration of 20 ng/mL and 10^-7mol/L respectively. Quantification of VSMC proliferation involved MTT and BrdU assay and migration was detected by wound-healing assay. Western blot and realtime PCR were used to detect the protein and mRNA levels of tissues or cells.

RESULTS

With the rat carotid-artery balloon-injury model, IMD was significantly downregulated in injured arteries and plasma. Exogenous IMD_1-53 greatly inhibited neointima formation and prevented VSMC from switching to a synthetic phenotype. With the left common carotid-artery ligation-injury model, IMD-transgenic mice showed less neointima formation than C57BL/6J mice. PDGF-BB reduced IMD mRNA expression in rat primary cultured VSMCs but increased that of its receptors, calcitonin receptor-like receptor or receptor activity-modifying proteins. Furthermore, PDGF-BB promoted VSMC proliferation and migration and transformed VSMCs to the synthetic phenotype, which was reversed with IMD_1-53 treatment. Mechanistically, IMD_1-53 maintained the contractile VSMC phenotype via the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway.

CONCLUSIONS

IMD attenuated neointima formation both in the rat model of carotid-artery balloon injury and mouse model of common carotid-artery ligation injury. IMD protection may be mediated by maintaining a VSMC contractile phenotype via the cAMP/PKA pathway.

Vascular Smooth Muscle Cells and Arterial Stiffening: Relevance in Development, Aging, and Disease

The cushioning function of large arteries encompasses distension during systole and recoil during diastole which transforms pulsatile flow into a steady flow in the microcirculation. Arterial stiffness, the inverse of distensibility, has been implicated in various etiologies of chronic common and monogenic cardiovascular diseases and is a major cause of morbidity and mortality globally. The first components that contribute to arterial stiffening are extracellular matrix (ECM) proteins that support the mechanical load, while the second important components are vascular smooth muscle cells (VSMCs), which not only regulate actomyosin interactions for contraction but mediate also mechanotransduction in cell-ECM homeostasis. Eventually, VSMC plasticity and signaling in both conductance and resistance arteries are highly relevant to the physiology of normal and early vascular aging. This review summarizes current concepts of central pressure and tensile pulsatile circumferential stress as key mechanical determinants of arterial wall remodeling, cell-ECM interactions depending mainly on the architecture of cytoskeletal proteins and focal adhesion, the large/small arteries cross-talk that gives rise to target organ damage, and inflammatory pathways leading to calcification or atherosclerosis. We further speculate on the contribution of cellular stiffness along the arterial tree to vascular wall stiffness. In addition, this review provides the latest advances in the identification of gene variants affecting arterial stiffening. Now that important hemodynamic and molecular mechanisms of arterial stiffness have been elucidated, and the complex interplay between ECM, cells, and sensors identified, further research should study their potential to halt or to reverse the development of arterial stiffness.

Role of noncoding RNA in vascular remodelling

PURPOSE OF REVIEW

Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are becoming fundamentally important in the pathophysiology relating to injury-induced vascular remodelling. We highlight recent studies that demonstrate the involvement of ncRNAs in vein graft disease, in in-stent restenosis and in pulmonary arterial hypertension, with a particular focus on endothelial cell and vascular smooth muscle cell function. We also briefly discuss the emerging role of exosomal-derived ncRNAs and how this mechanism impacts on vascular function.

RECENT FINDINGS

ncRNAs have been described as novel regulators in the pathophysiology of vascular injury, inflammation, and vessel wall remodelling. In particular, several studies have demonstrated that manipulation of miRNAs can reduce the burden of pathological vascular remodelling. Such studies have also shown that exosomal miRNA-mediated, cell-to-cell communication between endothelial cells and vascular smooth muscle cells is critical in the disease process. In addition to miRNAs, lncRNAs are emerging as regulators of vascular function in health and disease. Although lncRNAs are complex in both their sheer numbers and mechanisms of action, identifying their contribution to vascular disease is essential.

SUMMARY

Given the important roles of ncRNAs in vascular injury and remodelling together will their capacity for cell-to-cell communication, manipulating ncRNA might provide novel therapeutic interventions.

Transcriptome-Wide Expression Profiling in Skin Fibroblasts of Patients with Joint Hypermobility Syndrome/Ehlers-Danlos Syndrome Hypermobility Type

Joint hypermobility syndrome/Ehlers–Danlos syndrome hypermobility type (JHS/EDS-HT), is likely the most common systemic heritable connective tissue disorder, and is mostly recognized by generalized joint hypermobility, joint instability complications, minor skin changes and a wide range of satellite features. JHS/EDS-HT is considered an autosomal dominant trait but is still without a defined molecular basis. The absence of (a) causative gene(s) for JHS/EDS-HT is likely attributable to marked genetic heterogeneity and/or interaction of multiple loci. In order to help in deciphering such a complex molecular background, we carried out a comprehensive immunofluorescence analysis and gene expression profiling in cultured skin fibroblasts from five women affected with JHS/EDS-HT. Protein study revealed disarray of several matrix structural components such as fibrillins, tenascins, elastin, collagens, fibronectin, and their integrin receptors. Transcriptome analysis indicated perturbation of different signaling cascades that are required for homeostatic regulation either during development or in adult tissues as well as altered expression of several genes involved in maintenance of extracellular matrix architecture and homeostasis (e.g., SPON2, TGM2, MMP16, GPC4, SULF1), cell-cell adhesion (e.g., CDH2, CHD10, PCDH9, CLDN11, FLG, DSP), immune/inflammatory/pain responses (e.g., CFD, AQP9, COLEC12, KCNQ5, PRLR), and essential for redox balance (e.g., ADH1C, AKR1C2, AKR1C3, MAOB, GSTM5). Our findings provide a picture of the gene expression profile and dysregulated pathways in JHS/EDS-HT skin fibroblasts that correlate well with the systemic phenotype of the patients.

Mindin deficiency protects the liver against ischemia/reperfusion injury

BACKGROUND & AIMS

Hepatic ischemia/reperfusion (I/R) injury often occurs during liver surgery and may cause liver failure. Our previous studies revealed that Mindin is involved in the pathogenesis of ischemic stroke. However, the function of Mindin in hepatic I/R injury remains unknown.

METHODS

Partial hepatic warm ischemia was induced in parallel in global Mindin knockout mice (Mindin KO), hepatocyte-specific Mindin knockdown mice, hepatocyte-specific Mindin transgenic mice (Mindin TG), myeloid cell-specific Mindin TG mice (LysM-Mindin TG), and their corresponding controls, followed by reperfusion. Hepatic histology, serum aminotransferase, inflammatory cytokines, and hepatocyte apoptosis and proliferation were examined to assess liver injury. The molecular mechanisms of Mindin function were explored in vivo and in vitro.

RESULTS

Mindin KO and hepatocyte-specific Mindin knockdown mice exhibited less liver damage than controls, with smaller necrotic areas and lower serum transaminase levels. Mindin deficiency significantly suppressed inflammatory cell infiltration, cytokine and chemokine production, and hepatocyte apoptosis, but increased hepatocyte proliferation following hepatic I/R injury. In contrast, the opposite pathological and biochemical changes were observed in hepatocyte-specific Mindin TG mice, whereas no significant changes in liver damage were found in LysM-Mindin TG mice compared to non-transgenic controls. Mechanistically, Akt signaling was activated in livers of Mindin KO mice but was suppressed in Mindin TG mice. Most importantly, Akt inhibitor treatment blocked the protective effect of Mindin deficiency on hepatic I/R injury.

CONCLUSIONS

Mindin is a novel modulator of hepatic I/R injury through regulating inflammatory responses, as well as hepatocyte apoptosis and proliferation via inactivation of the Akt signaling pathway.