Smooth Muscle-Alpha Actin Inhibits Vascular Smooth Muscle Cell Proliferation and Migration by Inhibiting Rac1 Activity

Ex vivo expansion in a clinical grade medium, containing growth factors from human platelets, enhances migration capacity of adipose stem cells

Introduction

Adipose tissue mesenchymal stem/stromal cells (ASC) can be used as advanced therapy medicinal product in regenerative and cancer medicine. We previously demonstrated Supernatant Rich in Growth Factors (SRGF) can replace fetal bovine serum (FBS) to expand ASC by a clinical grade compliant protocol. The therapeutic potential of ASC is based also on their homing capacity toward inflammatory/cancer sites: oriented cell migration is a fundamental process in this scenario. We investigated the impact of SRGF on ASC migration properties.

Methods

The motility/migration potential of ASC expanded in 5% SRGF was analyzed, in comparison to 10% FBS, by standard wound healing, bidimensional chemotaxis and transwell assays, and by millifluidic transwell tests. Mechanisms involved in the migration process were investigated by transient protein overexpression.

Results

In comparison to standard 10% FBS, supplementation of the cell culture medium with 5% SRGF, strongly increased migration properties of ASC along the chemotactic gradient and toward cancer cell derived soluble factors, both in static and millifluidic conditions. We showed that, independently from applied migratory stimulus, SRGF expanded ASC were characterized by far lower expression of α-smooth muscle actin (αSMA), a protein involved in the cell migration machinery. Overexpression of αSMA induced a significant and marked decrease in migration capacity of SRGF expanded ASC.

Discussion

In conclusion, 5% SRGF addition in the cell culture medium increases the migration potential of ASC, reasonably through appropriate downregulation of αSMA. Thus, SRGF could potentially improve the therapeutic impact of ASC, both as modulators of the immune microenviroment or as targeted drug delivery vehicles in oncology.

Targeting Oncostatin M Receptor to Attenuate Carotid Artery Plaque Vulnerability in Hypercholesterolemic Microswine

Atherosclerosis is a chronic inflammatory disease that leads to acute embolism via the formation of atherosclerotic plaques. Plaque formation is first induced by fatty deposition along the arterial intima. Inflammation, bacterial infection, and the released endotoxins can lead to dysfunction and phenotypic changes of vascular smooth muscle cells (VSMCs), advancing the plaque from stable to unstable form and prone to rupture. Stable plaques are characterized by increased VSMCs and less inflammation while vulnerable plaques develop due to chronic inflammation and less VSMCs. Oncostatin M (OSM), an inflammatory cytokine, plays a role in endothelial cells and VSMC proliferation. This effect of OSM could be modulated by p27KIP1, a cyclin-dependent kinase (CDK) inhibitor. However, the role of OSM in plaque vulnerability has not been investigated. To better understand the role of OSM and its downstream signaling including p27KIP1 in plaque vulnerability, we characterized the previously collected carotid arteries from hyperlipidemic Yucatan microswine using hematoxylin and eosin stain, Movat Pentachrome stain, and gene and protein expression of OSM and p27KIP1 using immunostaining and real-time polymerase chain reaction. OSM and p27KIP1 expression in carotid arteries with angioplasty and treatment with either scrambled peptide or LR12, an inhibitor of triggering receptor expressed on myeloid cell (TREM)-1, were compared between the experimental groups and with contralateral carotid artery. The results of this study elucidated the presence of OSM and p27KIP1 in carotid arteries with plaque and their association with arterial plaque and vulnerability. The findings suggest that targeting OSM and p27KIP1 axis regulating VSMC proliferation may have therapeutic significance to stabilize plaque.

Three-Dimensional Histological Characterization of the Placental Vasculature Using Light Sheet Microscopy

The placenta is the first embryonic organ, representing the connection between the embryo and the mother, and is therefore necessary for the embryo's growth and survival. To meet the ever-growing need for nutrient and gas exchange, the maternal spiral arteries undergo extensive remodeling, thus increasing the uteroplacental blood flow by 16-fold. However, the insufficient remodeling of the spiral arteries can lead to severe pregnancy-associated disorders, including but not limited to pre-eclampsia. Insufficient endovascular trophoblast invasion plays a key role in the manifestation of pre-eclampsia; however, the underlying processes are complex and still unknown. Classical histopathology is based on two-dimensional section microscopy, which lacks a volumetric representation of the vascular remodeling process. To further characterize the uteroplacental vascularization, a detailed, non-destructive, and subcellular visualization is beneficial. In this study, we use light sheet microscopy for optical sectioning, thus establishing a method to obtain a three-dimensional visualization of the vascular system in the placenta. By introducing a volumetric visualization method of the placenta, we could establish a powerful tool to deeply investigate the heterogeneity of the spiral arteries during the remodeling process, evaluate the state-of-the-art treatment options, effects on vascularization, and, ultimately, reveal new insights into the underlying pathology of pre-eclampsia.

Empagliflozin Attenuates Vascular Calcification in Mice with Chronic Kidney Disease by Regulating the NFR2/HO-1 Anti-Inflammatory Pathway through AMPK Activation

Vascular calcification (VC) is associated with increased cardiovascular risks in patients with chronic kidney disease (CKD). Sodium-glucose cotransporter 2 inhibitors, such as empagliflozin, can improve cardiovascular and renal outcomes. We assessed the expression of Runt-related transcription factor 2 (Runx2), interleukin (IL)-1β, IL-6, AMP-activated protein kinase (AMPK), nuclear factor erythroid-2-related factor (Nrf2), and heme oxygenase 1 (HO-1) in inorganic phosphate-induced VC in mouse vascular smooth muscle cells (VSMCs) to investigate the mechanisms underlying empagliflozin's therapeutic effects. We evaluated biochemical parameters, mean artery pressure (MAP), pulse wave velocity (PWV), transcutaneous glomerular filtration rate (GFR), and histology in an in vivo mouse model with VC induced by an oral high-phosphorus diet following a 5/6 nephrectomy in ApoE^-/- mice. Compared to the control group, empagliflozin-treated mice showed significant reductions in blood glucose, MAP, PWV, and calcification, as well as increased calcium and GFR levels. Empagliflozin inhibited osteogenic trans-differentiation by decreasing inflammatory cytokine expression and increasing AMPK, Nrf2, and HO-1 levels. Empagliflozin mitigates high phosphate-induced calcification in mouse VSMCs through the Nrf2/HO-1 anti-inflammatory pathway by activating AMPK. Animal experiments suggested that empagliflozin reduces VC in CKD ApoE^-/- mice on a high-phosphate diet.

In vivo evaluation of compliance mismatch on intimal hyperplasia formation in small diameter vascular grafts

Small diameter synthetic vascular grafts have high failure rate due to the thrombosis and intimal hyperplasia formation. Compliance mismatch between the synthetic graft and native artery has been speculated to be one of the main causes of intimal hyperplasia. However, changing the compliance of synthetic materials without altering material chemistry remains a challenge. Here, we used poly(vinyl alcohol) (PVA) hydrogel as a graft material due to its biocompatibility and tunable mechanical properties to investigate the role of graft compliance in the development of intimal hyperplasia and in vivo patency. Two groups of PVA small diameter grafts with low compliance and high compliance were fabricated by dip casting method and implanted in a rabbit carotid artery end-to-side anastomosis model for 4 weeks. We demonstrated that the grafts with compliance that more closely matched with rabbit carotid artery had lower anastomotic intimal hyperplasia formation and higher graft patency compared to low compliance grafts. Overall, this study suggested that reducing the compliance mismatch between the native artery and vascular grafts is beneficial for reducing intimal hyperplasia formation.

Cross-linking porcine peritoneum by oxidized konjac glucomannan: a novel method to improve the properties of cardiovascular substitute material

The use of natural polysaccharide crosslinkers for decellularized matrices is an effective approach to prepare cardiovascular substitute materials. In this research, NaIO4 was applied to oxidize konjac glucomannan to prepare the polysaccharide crosslinker oxidized konjac glucomannan (OKGM). The as-prepared crosslinker was then used to stabilize collagen-rich decellularized porcine peritoneum (DPP) to construct a cardiovascular substitute material (OKGM-fixed DPP). The results demonstrated that compared with GA-fixed DPP and GNP-fixed DPP, 3.75% OKGM [1:1.5 (KGM: NaIO4)]-fixed DPP demonstrated suitable mechanical properties, as well as good hemocompatibility, excellent anti-calcification capability, and anti-enzymolysis in vitro. Furthermore, 3.75% OKGM [1:1.5 (KGM: NaIO4)]-fixed DPP was suitable for vascular endothelial cell adhesion and rapid proliferation, and a single layer of endothelial cells was formed on the fifth day of culture. The in vivo experimental results also showed excellent histocompatibility. The current results demonstrted that OKGM was a novel polysaccharide cross-linking reagent for crosslinking natural tissues featured with rich collagen content, and 3.75% OKGM [1:1.5 (KGM: NaIO4)]-fixed DPP was a potential cardiovascular substitute material.

Graphical Abstract

Methotrexate conjugated gold nanoparticles improve rheumatoid vascular dysfunction in rat adjuvant-induced arthritis: gold revival

Endothelial vasomotor dysfunction and accelerated atherosclerosis encompass the features of rheumatoid vascular dysfunction (RVD), increasing cardiovascular morbidity and mortality among rheumatoid arthritis (RA) patients. Methotrexate, among DMARDs, effectively reduces cardiovascular events, but its non-selectivity together with its pharmacokinetic variability often limit drug adherence and contribute to its potential toxicity. Thus, methotrexate was conjugated to gold nanoparticles (MTX/AuNPs) and its effect on RVD in rats' adjuvant-induced arthritis was evaluated. A comparative study between MTX/AuNPs, free MTX, and AuNPs treatments on joint inflammation, vascular reactivity and architecture, smooth muscle phenotype, systemic inflammation, and atherogenic profile was done. Since MTX/AuNPs effect was superior, it appears that conjugation of MTX to AuNPs demonstrated a synergistic action. MTX immunomodulatory action combined with AuNPs anti-atherogenic potential yielded prompt control of whole features of RVD. These findings highlight the usefulness of nanoparticles-targeted drug-delivery system in refining rheumatoid-induced vascular dysfunction treatment and reviving gold use in RA.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

MiR-93 inhibits the vascular calcification of chronic renal failure by suppression of Wnt/β-catenin pathway

OBJECTIVE

To explore the effect of miR-93-mediated Wnt/β-catenin pathway on the vascular calcification (VC) of chronic renal failure (CRF).

METHODS

SD rats were utilized to construct CRF models and divided into Control, CRF, CRF + LV (lentiviral vector)-miR-93 and CRF + LV-Con groups. Renal tissues collected from rats were performed hematoxylin and eosin (HE) staining and Masson staining, while the abdominal aorta was dissected for alizarin red staining and Von Kossa staining. VC-related genes were determined by qRT-PCR while Wnt/β-catenin pathway-related proteins were examined by Western blotting.

RESULTS

As compared to Control group, the serum levels of blood urea nitrogen (BUN), serum creatinine (Scr), phosphorus (P), cystatin C (Cys-C) and 24-h urea protein (24 h Upro), and the scores of renal interstitial lesion and fibrotic area in rats from CRF group were elevated, with the increased calcified area of aorta as well as the enhanced calcium content and ALP. Meanwhile, rats in the CRF group had up-regulated expression of OPN, OCN, RUNX2 and BMP-2 and down-regulated expression of miR-93. As for the expression of Wnt/β-catenin pathway, rats in the CRF group had sharp increases in the protein expression of TCF4 and β-catenin, while α-SMA was down-regulated. However, changes of the above were reversed in rats from CRF + LV-miR-93 group, and TCF4 was confirmed to be a target gene of miR-93.

CONCLUSION

MiR-93, via inhibiting the activity of Wnt/β-catenin pathway by targeting TCF4, can improve the renal function of CRF rats, thereby mitigating the vascular calcification of CRF.

MFG-E8 Regulates Vascular Smooth Muscle Cell Migration Through Dose-Dependent Mediation of Actin Polymerization

Background Migration of vascular smooth muscle cells (VSMCs) is the main contributor to neointimal formation. The Arp2/3 (actin-related proteins 2 and 3) complex activates actin polymerization and is involved in lamellipodia formation during VSMC migration. Milk fat globule-epidermal growth factor 8 (MFG-E8) is a glycoprotein expressed in VSMCs. We hypothesized that MFG-E8 regulates VSMC migration through modulation of Arp2/3-mediated actin polymerization. Methods and Results To determine whether MFG-E8 is essential for VSMC migration, a model of neointimal hyperplasia was induced in the common carotid artery of wild-type and MFG-E8 knockout mice, and the extent of neointimal formation was evaluated. Genetic deletion of MFG-E8 in mice attenuated injury-induced neointimal hyperplasia. Cultured VSMCs deficient in MFG-E8 exhibited decreased cell migration. Immunofluorescence and immunoblotting revealed decreased Arp2 but not Arp3 expression in the common carotid arteries and VSMCs deficient in MFG-E8. Exogenous administration of recombinant MFG-E8 biphasically and dose-dependently regulated the cultured VSMCs. At a low concentration, MFG-E8 upregulated Arp2 expression. By contrast, MFG-E8 at a high concentration reduced the Arp2 level and significantly attenuated actin assembly. Arp2 upregulation mediated by low-dose MFG-E8 was abolished by treating cultured VSMCs with β1 integrin function-blocking antibody and Rac1 inhibitors. Moreover, treatment of the artery with a high dose of recombinant MFG-E8 diminished injury-induced neointimal hyperplasia and reduced VSMC migration. Conclusions MFG-E8 plays a critical role in VSMC migration through dose-dependent regulation of Arp2-mediated actin polymerization. These findings suggest that high doses of MFG-E8 may have therapeutic potential for treating vascular occlusive diseases.

Pericyte-specific deletion of ninjurin-1 induces fragile vasa vasorum formation and enhances intimal hyperplasia of injured vasculature

Adventitial abnormalities including enhanced vasa vasorum malformation are associated with development and vulnerability of atherosclerotic plaque. However, the mechanisms of vasa vasorum malformation and its role in vascular remodeling have not been fully clarified. We recently reported that ninjurin-1 (Ninj1) is a crucial adhesion molecule for pericytes to form matured neovessels. The purpose is to examine if Ninj1 regulates adventitial angiogenesis and affects the vascular remodeling of injured vessels using pericyte-specific Ninj1 deletion mouse model. Mouse femoral arteries were injured by insertion of coiled wire. Four weeks after vascular injury, fixed arteries were decolorized. Vascular remodeling, including intimal hyperplasia and adventitial microvessel formation were estimated in a three-dimensional view. Vascular fragility, including blood leakiness was estimated by extravasation of fluorescein isothiocyanate (FITC)-lectin or FITC-dextran from microvessels. Ninj1 expression was increased in pericytes in response to vascular injury. NG2-CreER/Ninj1^loxp mice were treated with tamoxifen (Tam) to induce deletion of Ninj1 in pericyte (Ninj1 KO). Tam-treated NG2-CreER or Tam-nontreated NG2-CreER/Ninj1^loxp mice were used as controls. Intimal hyperplasia was significantly enhanced in Ninj1 KO compared with controls. Vascular leakiness was significantly enhanced in Ninj1 KO. In Ninj1 KO, the number of infiltrated macrophages in adventitia was increased, along with the expression of inflammatory cytokines. In conclusion, deletion of Ninj1 in pericytes induces the immature vasa vasorum formation of injured vasculature and exacerbates adventitial inflammation and intimal hyperplasia. Thus, Ninj1 contributes to the vasa vasorum maturation in response to vascular injury and to reduction of vascular remodeling.NEW & NOTEWORTHY Although abnormalities of adventitial vasa vasorum are associated with vascular remodeling such as atherosclerosis, the mechanisms of vasa vasorum malformation and its role in vascular remodeling have not been fully clarified. The present study provides a line of novel evidence that ninjurin-1 contributes to adventitial microvascular maturation during vascular injury and regulates vascular remodeling.

The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis

OBJECTIVE

Since the systemic drugs have been used to reduce the hyperplasic response in the tunica intima, the periadventitial local drug applications to the vascular wall have gained more popularity. In this study, we investigated the effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis to explore the effects of these two different agents.

METHODS

21 New Zealand male rabbits were randomly divided into three groups. The carotid artery transection and anastomosis was performed onthe control group. The bovine serum albumin-glutaraldehyde and the polyethylene glycol polymer were applied locally on the other two groups seperatley after transection and anastomosis of the carotid arteries. At the end of 28-day follow-up, the histological and the immunohistochemical results related to neointimal hyperplasia were compared.

RESULTS

The glue residues were detected in the BSA-glutaraldehyde group, but in the PEG polymer group there was no glue residue. The intima thickness and the intima/media thickness ratio in the control group was significantly higher (p<0.05) than the other groups. These values did not differ significantly between the BSA-glutaraldehyde group and the PEG polymer group (p>0.05). The lumen diameter and the area in the control group were significantly higher (p < 0.05) than the BSA-glutaraldehyde group. These values between the control group and the PEG polymer group did not differ significantly (p>0.05). aSMA-positive staining score in the Control group was found to be significantly lower (p < 0.05) than the BSA-glutaraldehyde and PEG polymer group and the VEGF-positive staining score in the control group was found to be significantly higher (p < 0.05) than the BSA-glutaraldehyde and the PEG polymer group.

CONCLUSIONS

Although the both agents have positive results on neointimal hyperplasia, it would be favorable to use polyethylene glycol polymer, since it does not seem to affect the lumen area and the lumen diameter of the vessel.

Rac1 silencing, NSC23766 and EHT1864 reduce growth and actin organization of bladder smooth muscle cells

AIMS

RacGTPase-mediated proliferation and smooth muscle contraction in the lower urinary tract has been recently suggested and may offer putative targets for treamtment of lower urinary tract symptoms. However, RacGTPase function for proliferation of detrusor smooth muscle cells is unknown and the specificity of Rac inhibitors has been questioned. Here, we examined effects of Rac1 knockdown and of the Rac inhibitors NSC23766 and EHT1864 in human bladder smooth muscle cells (hBSMCs).

MAIN METHODS

Rac1 expression was silenced by shRNA expression. Effects of silencing and Rac inhibitors were assessed by CCK-8 assay, EdU staining, RT-PCR, colony formation assay, flow cytometry, and phalloidin staining.

KEY FINDINGS

Silencing of Rac1 expression reduced the viability (up to 83% compared to scramble shRNA) and proliferation (virtually completely in proliferation assay), increased apoptosis (124%) and the number of dead cells (51%), and caused breakdown of actin organization (56% reduction of polymerized actin compared to scramble shRNA). Effects on proliferation, viability, and actin organization were mimicked by NSC23766 and EHT1864, while both compounds showed divergent effects on cell death (32-fold increase of dead cells by EHT1864, but not NSC23766). Effects of NSC23766 and EHT1864 on viability of hBSMCs were not altered by Rac1 knockdown.

SIGNIFICANCE

Rac1 promotes proliferation, viability, and cytoskeletal organization, and suppresses apoptosis in bladder smooth muscle cells, which may be relevant in overactive bladder or diabetes-related bladder dysfunction. NSC23766 and EHT1864 mimick these effects, but may act Rac1-independently, by shared and divergent effects.

A Pulsatile Flow System to Engineer Aneurysm and Atherosclerosis Mimetic Extracellular Matrix

Alterations of blood flow patterns strongly correlate with arterial wall diseases such as atherosclerosis and aneurysm. Here, a simple, pumpless, close-loop, easy-to-replicate, and miniaturized flow device is introduced to concurrently expose 3D engineered vascular smooth muscle tissues to high-velocity pulsatile flow versus low-velocity disturbed flow conditions. Two flow regimes are distinguished, one that promotes elastin and impairs collagen I assembly, while the other impairs elastin and promotes collagen assembly. This latter extracellular matrix (ECM) composition shares characteristics with aneurysmal or atherosclerotic tissue phenotypes, thus recapitulating crucial hallmarks of flow-induced tissue morphogenesis in vessel walls. It is shown that the mRNA levels of ECM of collagens and elastin are not affected by the differential flow conditions. Instead, the differential gene expression of matrix metalloproteinase (MMP) and their inhibitors (TIMPs) is flow-dependent, and thus drives the alterations in ECM composition. In further support, treatment with doxycycline, an MMP inhibitor and a clinically used drug to treat vascular diseases, halts the effect of low-velocity flow on the ECM remodeling. This illustrates how the platform can be exploited for drug efficacy studies by providing crucial mechanistic insights into how different therapeutic interventions may affect tissue growth and ECM assembly.

CD36 Enhances Vascular Smooth Muscle Cell Proliferation and Development of Neointimal Hyperplasia

Objective- Dysregulated proliferation of vascular smooth muscle cells (VSMC) plays an essential role in neointimal hyperplasia. CD36 functions critically in atherogenesis and thrombosis. We hypothesize that CD36 regulates VSMC proliferation and contributes to the development of obstructive vascular diseases. Approach and Results- We found by immunofluorescent staining that CD36 was highly expressed in human vessels with obstructive diseases. Using guidewire-induced carotid artery injury and shear stress-induced intima thickening models, we compared neointimal hyperplasia in Apoe^-/-, Cd36^-/- /Apoe^-/-, and CD36 specifically deleted in VSMC (VSMC ^cd36-/-) mice. CD36 deficiency, either global or VSMC-specific, dramatically reduced injury-induced neointimal thickening. Correspondingly, carotid artery blood flow was significantly increased in Cd36^-/- /Apoe^-/- compared with Apoe^-/- mice. In cultured VSMCs from thoracic aorta of wild-type and Cd36^-/- mice, we found that loss of CD36 significantly decreased serum-stimulated proliferation and increased cell populations in S phase, suggesting that CD36 is necessary for VSMC S/G2-M-phase transition. Treatment of VSMCs with a TSR (thrombospondin type 1 repeat) peptide significantly increased wild-type, but not Cd36^-/- VSMC proliferation. TSR or serum treatment significantly increased cyclin A expression in wild-type, but not in Cd36^-/- VSMCs. STAT3 (signal transducer and activator of transcription), which reportedly enhances both VSMC differentiation and maturation, was higher in Cd36^-/- VSMCs. CD36 deficiency significantly decreased expression of Col1A1 (type 1 collagen A1 chain) and TGF-β1 (transforming growth factor beta 1), and increased expression of contractile proteins, including calponin 1 and smooth muscle α actin, and dramatically increased cell contraction. Conclusions- CD36 promotes VSMC proliferation via upregulation of cyclin A expression that contributes to the development of neointimal hyperplasia, collagen deposition, and obstructive vascular diseases.

Deletion of the FHL2 gene attenuates intima-media thickening in a partially ligated carotid artery ligated mouse model

The four and a half LIM domain protein 2 (FHL2) is a member of the four and a half LIM domain (FHL) gene family, and it is associated with cholesterol‐enriched diet‐promoted atherosclerosis. However, the effect of FHL2 protein on vascular remodelling in response to hemodynamic alterations remains unclear. Here, we investigated the role of FHL2 in a model of restricted blood flow‐induced atherosclerosis. To promote neointimal hyperplasia in vivo, we subjected FHL2^+/+ and FHL2^−/− mice to partial ligation of the left carotid artery (LCA). The expression of p‐ERK and p‐AKT was decreased in FHL2^−/− mice. FHL2 bound to AKT regulated AKT phosphorylation and led to Rac1‐GTP inactivation. FHL2 silencing in human aortic smooth muscle cells down‐regulated the PDGF‐induced phosphorylation of ERK and AKT. Furthermore, FHL2 silencing reduced cytoskeleton conformational changes and caused cell cycle arrest. We concluded that FHL2 is essential for the regulation of arterial smooth muscle cell function. FHL2 modulates proliferation and migration via mitogen‐activated protein kinase (MAPK) and PI3K‐AKT signalling, leading to arterial wall thickening and thus neointimal hyperplasia.

Pericytes in Skeletal Muscle

Skeletal muscle regeneration is a highly orchestrated process and involves the activation of many cellular and molecular pathways. Although satellite cells (SCs) are the major cell type responsible for muscle regeneration, pericytes show remarkable myogenic potential and various advantages as cell therapy in muscular disorders. This chapter first introduces the structure, marker expression, origin, and category of pericytes. Next, we discuss their functions in muscular dystrophy and/or muscle injuries, focusing on their myogenic, adipogenic, fibrogenic, chondrogenic, and osteogenic activities. Understanding this knowledge will promote the development of innovative cell therapies for muscle disorders, including muscular dystrophy.

The expression of HOXA13 in lung adenocarcinoma and its clinical significance: A study based on The Cancer Genome Atlas, Oncomine and reverse transcription-quantitative polymerase chain reaction

Previous studies have investigated the association between HOXA13 and non-small cell lung cancer. However, the role of HOXA13 expression in the occurrence and progression of lung adenocarcinoma (LUAD) has not yet been investigated. In the present study, HOXA13-related data mining of The Cancer Genome Atlas (TCGA), polymerase chain reaction (PCR) data from our cases and the case information in Oncomine was conducted for validation. The expression data of HOXA13 in lung cancer cell lines were also collected from the Cancer Cell Line Encyclopedia (CCLE) database for further verification. A comprehensive meta-analysis of the expression of HOXA13 was also performed, integrating the data of TCGA, in-house PCR and Oncomine. Genes that were co-expressed with HOXA13 were subsequently identified through cBioPortal and Multi Experiment Matrix (MEM), and the potential role and mechanism of HOXA13 in LUAD was investigated. The expression value of HOXA13 in the LUAD group, which comprised 237 cases, was 3.74±2.694, significantly higher than its expression value in the non-cancerous group (0.92±0.608, P<0.001). The pooled SMD for HOXA13 was 0.346 (95% CI, 0.052–0.640; P=0.068; I2=51.3%; P=0.021), The meta-analysis of diagnostic tests revealed that the area under the summary receiver operating characteristic curve (SROC) was 0.78 (95% CI, 0.75–0.82). The results demonstrated that HOXA13 is highly expressed in LUAD. In addition to the studies on HOXA13 expression in tissues, the expression data of HOXA13 in lung cancer cell lines were also collected from the CCLE database for further verification of these conclusions. Genes that were co-expressed with HOXA13 were identified for pathway analysis. The most enriched Gene Ontology terms in the genes co-expressed with HOXA13 were positive regulation of transcription from RNA polymerase II promoter, signal transduction and positive regulation of GTPase activity in biological process; cytoplasm, integral component of membrane and plasma membrane in cellular component; and significantly involved in protein binding, transcription factor activity, sequence-specific DNA binding and sequence-specific DNA binding in molecular function. Kyoto Encyclopedia of Genes and Genomes analysis revealed that these target genes were clearly involved in Pathways in cancer, Proteoglycans in cancer and cAMP signaling pathway. The hub genes obtained from the four protein-protein interaction networks were associated with HOXA13. The results of the bioinformatics research in the present study revealed that HOXA13 may influence the expression of these hub genes in such a way as to promote the occurrence and development of LUAD. In conclusion, the expression of HOXA13 in patients with LUAD and its potential clinical value were analyzed comprehensively in the present study using data from a variety of sources. Through bioinformatics analysis, evidence that HOXA13 may promote the occurrence and development of LUAD was obtained.

DFMG reverses proliferation and migration of vascular smooth muscle cells induced by co-culture with injured vascular endothelial cells via suppression of the TLR4-mediated signaling pathway

7-Difluoromethoxy-5,4′-dimethoxy-genistein (DFMG) is a novel chemical compound synthesized using genistein. Previous studies have indicated that DFMG can reverse the apoptosis of vascular endothelial cells (VECs) by regulating the mitochondrial apoptosis pathway. The present study aimed to investigate the activity and molecular mechanism underlying DFMG-mediated protection of vascular smooth muscle cell (VSMCs) using a non-contact co-culture model established by using Transwell insert. Secretion of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by ELISA. Proliferation and migration of VSMCs were assessed using a Cell Counting kit-8 and wound healing assays, respectively. Toll-like receptor 4 (TLR4) mRNA and protein levels were detected by reverse transcription-quantitative polymerase chain reaction and western blotting analyses, respectively. In the present study, lysophosphatidylcholine (LPC) significantly increased the secretion of IL-6 and TNF-α in VECs. VECs treated with LPC markedly increased proliferation and migration of VSMCs, which were inhibited by DFMG. Transfection of either TLR4 short hairpin RNA (shRNA) or TLR4 cDNA in VECs inhibited and increased proliferation and migration of VSMCs, respectively. Furthermore, transfection of VECs with TLR4 shRNA suppressed the proliferation and migration of VSMCs induced by co-culture with injured VECs, which was further enhanced by treatment with DFMG. By contrast, transfection of VECs with TLR4 cDNA enhanced proliferation and migration of VSMCs and this effect was inhibited by treatment with DFMG. Taken together, the results of the present study demonstrated that DFMG can reverse proliferation and migration of VSMCs induced by co-culture with injured VECs via suppression of the TLR4-mediated signaling 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.

Vascular disease-causing mutation, smooth muscle α-actin R258C, dominantly suppresses functions of α-actin in human patient fibroblasts

The most common genetic alterations for familial thoracic aortic aneurysms and dissections (TAAD) are missense mutations in vascular smooth muscle (SM) α-actin encoded by ACTA2 We focus here on ACTA2-R258C, a recurrent mutation associated with early onset of TAAD and occlusive moyamoya-like cerebrovascular disease. Recent biochemical results with SM α-actin-R258C predicted that this variant will compromise multiple actin-dependent functions in intact cells and tissues, but a model system to measure R258C-induced effects was lacking. We describe the development of an approach to interrogate functional consequences of actin mutations in affected patient-derived cells. Primary dermal fibroblasts from R258C patients exhibited increased proliferative capacity compared with controls, consistent with inhibition of growth suppression attributed to SM α-actin. Telomerase-immortalized lines of control and R258C human dermal fibroblasts were established and SM α-actin expression induced with adenovirus encoding myocardin-related transcription factor A, a potent coactivator of ACTA2 Two-dimensional Western blotting confirmed induction of both wild-type and mutant SM α-actin in heterozygous ACTA2-R258C cells. Expression of mutant SM α-actin in heterozygous ACTA2-R258C fibroblasts abrogated the significant effects of SM α-actin induction on formation of stress fibers and focal adhesions, filamentous to soluble actin ratio, matrix contraction, and cell migration. These results demonstrate that R258C dominantly disrupts cytoskeletal functions attributed to SM α-actin in fibroblasts and are consistent with deficiencies in multiple cytoskeletal functions. Thus, cellular defects due to this ACTA2 mutation in both aortic smooth muscle cells and adventitial fibroblasts may contribute to development of TAAD and proliferative occlusive vascular disease.

Nanoengineered Stent Surface to Reduce In-Stent Restenosis in Vivo

In-stent restenosis (ISR) is the leading cause of stent failure and is a direct result of a dysfunctional vascular endothelium and subsequent overgrowth of vascular smooth muscle tissue. TiO₂ nanotubular (NT) arrays have been shown to affect vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) in vitro by accelerating VEC cell proliferation and migration while suppressing VSMCs. This study investigates for the first time the potentially beneficial effects of TiO₂ NT arrays on vascular tissue in vivo. TiO₂ NT arrays (NT diameter: 90 ± 5 nm, height: 1800 ± 300 nm) were grown on the surface of titanium stents and characterized in terms of surface morphology and stability. Stents were implanted into the iliofemoral artery using an overinflation model (rabbit). After 28 days, stenosis rates were determined. The data show a statistically significant reduction of stenosis by 30% compared to the control. Tissue in the presence of TiO₂ NTs appears more mature, and less neointima is present between struts. In addition, the extra cellular matrix secreted by cells at the interface of the NT arrays shows complete integration into the nanostructured surface. These results document the accelerated restoration of a functional endothelium in the presence of TiO₂ NT arrays and substantiate their beneficial impact on vascular tissue in vivo. Our findings suggest that TiO₂ NT arrays can be used as a drug-free approach for keeping stents patent long-term and have the potential to address ISR.

Matrix stiffness regulates migration of human lung fibroblasts

In patients with pulmonary diseases such as idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome, progressive pulmonary fibrosis is caused by dysregulated wound healing via activation of fibroblasts after lung inflammation or severe damage. Migration of fibroblasts toward the fibrotic lesions plays an important role in pulmonary fibrosis. Fibrotic tissue in the lung is much stiffer than normal lung tissue. Emerging evidence supports the hypothesis that the stiffness of the matrix is not only a consequence of fibrosis, but also can induce fibroblast activation. Nevertheless, the effects of substrate rigidity on migration of lung fibroblasts have not been fully elucidated. We evaluated the effects of substrate stiffness on the morphology, α-smooth muscle actin (α-SMA) expression, and cell migration of primary human lung fibroblasts by using polyacrylamide hydrogels with stiffnesses ranging from 1 to 50 kPa. Cell motility was assessed by platelet-derived growth factor (PDGF)-induced chemotaxis and random walk migration assays. As the stiffness of substrates increased, fibroblasts became spindle-shaped and spread. Expression of α-SMA proteins was higher on the stiffer substrates (25 kPa gel and plastic dishes) than on the soft 2 kPa gel. Both PDGF-induced chemotaxis and random walk migration of fibroblasts precultured on stiff substrates (25 kPa gel and plastic dishes) were significantly higher than those of cells precultured on 2 kPa gel. Transfection of the fibroblasts with short interfering RNA for α-SMA inhibited cell migration. These findings suggest that fibroblast activation induced by a stiff matrix is involved in mechanisms of the pathophysiology of pulmonary fibrosis.