DJ-1/park7 protects against neointimal formation via the inhibition of vascular smooth muscle cell growth

Vascular smooth muscle cell dysfunction in neurodegeneration

Vascular smooth muscle cells (VSMCs) are the key moderators of cerebrovascular dynamics in response to the brain's oxygen and nutrient demands. Crucially, VSMCs may provide a sensitive biomarker for neurodegenerative pathologies where vasculature is compromised. An increasing body of research suggests that VSMCs have remarkable plasticity and their pathophysiology may play a key role in the complex process of neurodegeneration. Furthermore, extrinsic risk factors, including environmental conditions and traumatic events can impact vascular function through changes in VSMC morphology. VSMC dysfunction can be characterised at the molecular level both preclinically, and clinically ex vivo. However the identification of VSMC dysfunction in living individuals is important to understand changes in vascular function at the onset and progression of neurological disorders such as dementia, Alzheimer's disease, and Parkinson's disease. A promising technique to identify changes in the state of cerebral smooth muscle is cerebrovascular reactivity (CVR) which reflects the intrinsic dynamic response of blood vessels in the brain to vasoactive stimuli in order to modulate regional cerebral blood flow (CBF). In this work, we review the role of VSMCs in the most common neurodegenerative disorders and identify physiological systems that may contribute to VSMC dysfunction. The evidence collected here identifies VSMC dysfunction as a strong candidate for novel therapeutics to combat the development and progression of neurodegeneration, and highlights the need for more research on the role of VSMCs and cerebrovascular dynamics in healthy and diseased states.

Dj1 deficiency protects against atherosclerosis with anti-inflammatory response in macrophages

Inflammation is a key contributor to atherosclerosis with macrophages playing a pivotal role through the induction of oxidative stress and cytokine/chemokine secretion. DJ1, an anti-oxidant protein, has shown to paradoxically protect against chronic and acute inflammation. However, the role of DJ1 in atherosclerosis remains elusive. To assess the role of Dj1 in atherogenesis, we generated whole-body Dj1-deficient atherosclerosis-prone Apoe null mice (Dj1^-/-Apoe^-/-). After 21 weeks of atherogenic diet, Dj1^-/- Apoe^-/-mice were protected against atherosclerosis with significantly reduced plaque macrophage content. To assess whether haematopoietic or parenchymal Dj1 contributed to atheroprotection in Dj1-deficient mice, we performed bone-marrow (BM) transplantation and show that Dj1-deficient BM contributed to their attenuation in atherosclerosis. To assess cell-autonomous role of macrophage Dj1 in atheroprotection, BM-derived macrophages from Dj1-deficient mice and Dj1-silenced macrophages were assessed in response to oxidized low-density lipoprotein (oxLDL). In both cases, there was an enhanced anti-inflammatory response which may have contributed to atheroprotection in Dj1-deficient mice. There was also an increased trend of plasma DJ-1 levels from individuals with ischemic heart disease compared to those without. Our findings indicate an atheropromoting role of Dj1 and suggests that targeting Dj1 may provide a novel therapeutic avenue for atherosclerosis treatment or prevention.

Protein deglycase DJ-1 deficiency induces phenotypic switching in vascular smooth muscle cells and exacerbates atherosclerotic plaque instability

Protein deglycase DJ‐1 (DJ‐1) is a multifunctional protein involved in various biological processes. However, it is unclear whether DJ‐1 influences atherosclerosis development and plaque stability. Accordingly, we evaluated the influence of DJ‐1 deletion on the progression of atherosclerosis and elucidate the underlying mechanisms. We examine the expression of DJ‐1 in atherosclerotic plaques of human and mouse models which showed that DJ‐1 expression was significantly decreased in human plaques compared with that in healthy vessels. Consistent with this, the DJ‐1 levels were persistently reduced in atherosclerotic lesions of ApoE^−/− mice with the increasing time fed by western diet. Furthermore, exposure of vascular smooth muscle cells (VSMCs) to oxidized low‐density lipoprotein down‐regulated DJ‐1 in vitro. The canonical markers of plaque stability and VSMC phenotypes were evaluated in vivo and in vitro. DJ‐1 deficiency in Apoe^−/− mice promoted the progression of atherosclerosis and exaggerated plaque instability. Moreover, isolated VSMCs from Apoe^−/−DJ‐1^−/− mice showed lower expression of contractile markers (α‐smooth muscle actin and calponin) and higher expression of synthetic indicators (osteopontin, vimentin and tropoelastin) and Kruppel‐like factor 4 (KLF4) by comparison with Apoe^−/−DJ‐1^+/+ mice. Furthermore, genetic inhibition of KLF4 counteracted the adverse effects of DJ‐1 deletion. Therefore, our results showed that DJ‐1 deletion caused phenotype switching of VSMCs and exacerbated atherosclerotic plaque instability in a KLF4‐dependent manner.

Mitochondrial Translocation of DJ-1 Is Mediated by Grp75: Implication in Cardioprotection of Resveratrol Against Hypoxia/Reoxygenation-Induced Oxidative Stress

Resveratrol (Res) was recently reported to ameliorate hypoxia/reoxygenation (H/R)-caused oxidative stress in H9c2 cardiomyocytes through promoting the mitochondrial translocation of DJ-1 protein and subsequently preserving the activity of mitochondrial complex I. However, it is noteworthy that DJ-1 possesses no mitochondria-targeting sequence. Therefore, how Res induces DJ-1 mitochondrial translocation is an important and interesting question for further exploration. Glucose-regulated protein 75 (Grp75), whose N-terminus contains a 51-amino acid long mitochondrial-targeting signal peptide, is a cytoprotective chaperone that partakes in mitochondrial import of several proteins. Here, the contribution of Grp75 to mitochondrial import of DJ-1 by Res was investigated in a cellular model of H/R. Our results showed that Res upregulated the expression of DJ-1 protein, enhanced the interaction of DJ-1 and Grp75, and promoted DJ-1 translocation to mitochondria from cytosol in H9c2 cardiomyocytes undergoing H/R. Importantly, knockdown of Grp75 markedly reduced the interaction of DJ-1 with Grp75 and subsequent DJ-1 mitochondrial translocation induced by Res. Furthermore, Res pretreatment promoted the association of DJ-1 with ND1 and NDUFA4 subunits of complex I, preserved the activity of complex I, decreased mitochondria-derived reactive oxygen species production, and eventually ameliorated H/R-caused oxidative stress damage. Intriguingly, these effects were largely prevented also by small interfering RNA targeting Grp75. Overall, these results suggested that Grp75 interacts with DJ-1 to facilitate its translocation from cytosol to mitochondria, which is required for Res-mediated preservation of mitochondria complex I and cardioprotection from H/R-caused oxidative stress injury.

Role of DJ-1 in Immune and Inflammatory Diseases

The DJ-1 protein, known as an oxidative stress sensor, participates in the onset of oxidative stress-related diseases such as cancer, neurodegenerative disorders, type 2 diabetes, and male infertility. Although DJ-1 has been extensively studied for more than two decades, evidence has only recently emerged that it plays a key role in immune and inflammatory disorders. The immune regulatory function of DJ-1 is achieved by modulating the activation of several immune cells including macrophages, mast cells, and T cells via reactive oxygen species (ROS)-dependent and/or ROS-independent mechanisms. This review describes the current knowledge on DJ-1, focusing on its immune and inflammatory regulatory roles, and highlights the significance of DJ-1 as a novel therapeutic target for immune and inflammatory diseases.

Heat shock protein 90 inhibitor AUY922 attenuates platelet-derived growth factor-BB-induced migration and proliferation of vascular smooth muscle cells

Luminespib (AUY922), a heat shock proteins 90 inhibitor, has anti-neoplastic and antitumor effects. However, it is not clear whether AUY922 affects events in vascular diseases. We investigated the effects of AUY922 on the platelet-derived growth factor (PDGF)-BB-stimulated proliferation and migration of vascular smooth muscle cells (VSMC). VSMC viability was detected using the XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reagent. To detect the attenuating effects of AUY922 on PDGF-BB-induced VSMCs migration in vitro, we performed the Boyden chamber and scratch wound healing assays. To identify AUY922-mediated changes in the signaling pathway, the phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) 1/2 was analyzed by immunoblotting. The inhibitory effects of AUY922 on migration and proliferation ex vivo were tested using an aortic ring assay. AUY922 was not cytotoxic at concentrations up to 5 nM. PDGF-BB-induced VSMC proliferation, migration, and sprout outgrowth were significantly decreased by AUY922 in a dose-dependent manner. AUY922 significantly reduced the PDGF-BB-stimulated phosphorylation of Akt and ERK1/2. Furthermore, PD98059 (a selective ERK1/2 inhibitor) and LY294002 (a selective Akt inhibitor) decreased VSMC migration and proliferation by inhibiting phosphorylation of Akt and ERK1/2. Greater attenuation of PDGF-BB-induced cell viability and migration was observed upon treatment with PD98059 or LY294002 in combination with AUY922. AUY922 showed anti-proliferation and anti-migration effects towards PDGF-BBinduced VSMCs by regulating the phosphorylation of ERK1/2 and Akt. Thus, AUY922 is a candidate for the treatment of atherosclerosis and restenosis.

The effect of resveratrol supplementation on the expression levels of factors associated with cellular senescence and sCD163/sTWEAK ratio in patients with type 2 diabetes mellitus: study protocol for a double-blind controlled randomised clinical trial

INTRODUCTION

Over the past decades, the number of people with type 2 diabetes (T2D) has increased globally. One of the major complications in these patients is cardiovascular disease; it seems that the cell proliferation inhibition can improve vascular function in these patients. It is proposed that peroxisome proliferator-activated receptor alpha (PPARα) can induce cell cycle arrest via cyclin-dependent kinase inhibitor 2A (p16) activation. Also, it has been shown that phosphorylated tumour suppressor protein p53 is involved in cell senescence by cyclin-dependent kinase inhibitor 1 (p21) upregulation. Resveratrol is a natural polyphenol and appears to improve the vascular function through the mentioned pathways. We will aim to evaluate the effects of resveratrol supplementation on mRNA expression of PPARα, p53, p21 and p16 in patients with T2D. We will also measure serum levels of cluster of differentiation 163 (CD163) and tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) as the indicators of cardiovascular status.

METHODS AND ANALYSIS

Seventy-two subjects suffering from T2D will participate in this double-blind randomised parallel placebo-controlled clinical trial. Participants will be randomly assigned to receive 1000 mg/day trans-resveratrol or placebo (methyl cellulose) for 8 weeks. The mRNA expression levels of PPARα, p53, p21 and p16 genes will be assessed using real-time PCR and serum CD163 and TWEAK levels will be measured using commercially available ELISA kits at baseline and the end of the study. Clinical outcome parameters (glycaemic and lipid profiles and body composition) will also be measured before and after study duration.

ETHICS AND DISSEMINATION

The study is performed in agreement with the Declaration of Helsinki and is approved by the Ethics Committee of the Shahid Sadoughi University of Medical Sciences (no: ir.ssu.sph.rec.1396.120). The results will be published in scientific journals.

TRIAL REGISTRATION NUMBER

IRCT20171118037528N1; Pre-results.

A Novel Regulatory Mechanism for Differentiation of Mesenchymal Stem Cell: Redox State of DJ-1 Matters

Reactive oxygen species (ROS) are multifunctional gas transmitters with diverse biological actions (adverse vs beneficial) dependent on their level. The differentiation of vascular stem cells into smooth muscle cells (SMCs) might be involved in the pathogenesis of cardiovascular disorders including hypertension and atherosclerosis. Therefore, controlling the differentiation of vascular stem cells is a potential strategy for the treatment of vascular diseases. Nonetheless, it remains to be revealed whether ROS could mediate the differentiation of mesenchymal stem cells (MSCs) into SMCs. In addition, there are no redox (reduction-oxidation)-sensitive molecules identified, which are responsible for the ROS-induced differentiation of MSCs. In article number 1700208, Baek et al. [Proteomics 2017, 17, Issue 21] found that ROS mediate the differentiation of MSCs into SMCs through the modification of redox states of a multifunctional ROS-responsive protein, DJ-1, revealing a novel regulatory mechanism for differentiation of MSCs into SMCs and shedding light into the future development of stem-cell-targeted pharmacotherapy.

p38 Inhibitor Protects Mitochondrial Dysfunction by Induction of DJ-1 Mitochondrial Translocation After Subarachnoid Hemorrhage

p38 mitogen-activated protein kinase (MAPK) is a major player in mitochondrial dysfunction after subarachnoid hemorrhage (SAH). Moreover, DJ-1, which responds to oxidative stress and translocates to mitochondria, maintains mitochondrial homeostasis. Although a few studies have demonstrated that DJ-1 indirectly regulates p38 activation, the relationship between DJ-1 and p38 in mitochondrial dysfunction after SAH has not been delineated. Using an in vitro SAH model, alterations in p38, p-p38, DJ-1, and autophagic-related protein expression were detected. As expected, p38 inhibitor significantly blocked excessive expression of p38 and p-p38 after SAH, whereas total DJ-1 expression and mitochondrial DJ-1 were up-regulated. Further analysis showed that p38 inhibitor significantly blocked oxyhemoglobin (OxyHb) induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization and reactive oxygen species (ROS) release. In addition, p38 inhibitor restored OxyHb-induced abnormal autophagic flux at the initiation and formation stage by regulating Atg5, beclin-1, the ratio of LC3-II/LC3-I, and p62 expression. This study suggested that overexpression of p38 induced the accumulation of mitochondrial dysfunction partly due to abnormal activation of autophagy, which largely relied on DJ-1 mitochondrial translocation.

PARK7 modulates autophagic proteolysis through binding to the N-terminally arginylated form of the molecular chaperone HSPA5

Macroautophagy is induced under various stresses to remove cytotoxic materials, including misfolded proteins and their aggregates. These protein cargoes are collected by specific autophagic receptors such as SQSTM1/p62 (sequestosome 1) and delivered to phagophores for lysosomal degradation. To date, little is known about how cells sense and react to diverse stresses by inducing the activity of SQSTM1. Here, we show that the peroxiredoxin-like redox sensor PARK7/DJ-1 modulates the activity of SQSTM1 and the targeting of ubiquitin (Ub)-conjugated proteins to macroautophagy under oxidative stress caused by TNFSF10/TRAIL (tumor necrosis factor [ligand] superfamily, member 10). In this mechanism, TNFSF10 induces the N-terminal arginylation (Nt-arginylation) of the endoplasmic reticulum (ER)-residing molecular chaperone HSPA5/BiP/GRP78, leading to cytosolic accumulation of Nt-arginylated HSPA5 (R-HSPA5). In parallel, TNFSF10 induces the oxidation of PARK7. Oxidized PARK7 acts as a co-chaperone-like protein that binds the ER-derived chaperone R-HSPA5, a member of the HSPA/HSP70 family. By forming a complex with PARK7 (and possibly misfolded protein cargoes), R-HSPA5 binds SQSTM1 through its Nt-Arg, facilitating self-polymerization of SQSTM1 and the targeting of SQSTM1-cargo complexes to phagophores. The 3-way interaction among PARK7, R-HSPA5, and SQSTM1 is stabilized by the Nt-Arg residue of R-HSPA5. PARK7-deficient cells are impaired in the targeting of R-HSPA5 and SQSTM1 to phagophores and the removal of Ub-conjugated cargoes. Our results suggest that PARK7 functions as a co-chaperone for R-HSPA5 to modulate autophagic removal of misfolded protein cargoes generated by oxidative stress.

Notch2 and Proteomic Signatures in Mouse Neointimal Lesion Formation

Supplemental Digital Content is available in the text.

Objective—

Vascular remodeling is associated with complex molecular changes, including increased Notch2, which promotes quiescence in human smooth muscle cells. We used unbiased protein profiling to understand molecular signatures related to neointimal lesion formation in the presence or absence of Notch2 and to test the hypothesis that loss of Notch2 would increase neointimal lesion formation because of a hyperproliferative injury response.

Approach and Results—

Murine carotid arteries isolated at 6 or 14 days after ligation injury were analyzed by mass spectrometry using a data-independent acquisition strategy in comparison to uninjured or sham injured arteries. We used a tamoxifen-inducible, cell-specific Cre recombinase strain to delete the Notch2 gene in smooth muscle cells. Vessel morphometric analysis and immunohistochemical staining were used to characterize lesion formation, assess vascular smooth muscle cell proliferation, and validate proteomic findings. Loss of Notch2 in smooth muscle cells leads to protein profile changes in the vessel wall during remodeling but does not alter overall lesion morphology or cell proliferation. Loss of smooth muscle Notch2 also decreases the expression of enhancer of rudimentary homolog, plectin, and annexin A2 in vascular remodeling.

Conclusions—

We identified unique protein signatures that represent temporal changes in the vessel wall during neointimal lesion formation in the presence and absence of Notch2. Overall lesion formation was not affected with loss of smooth muscle Notch2, suggesting compensatory pathways. We also validated the regulation of known injury- or Notch-related targets identified in other vascular contexts, providing additional insight into conserved pathways involved in vascular remodeling.

Up-regulation of caveolin-1 by DJ-1 attenuates rat pulmonary arterial hypertension by inhibiting TGFβ/Smad signaling pathway

Pulmonary arterial hypertension (PAH), characterized by excessive proliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMCs), is closely associated with the imbalance in vasoactive mediators and massive remodeling of pulmonary vasculature. DJ-1/park7, a multifunctional protein, plays a critical defense role in several cytobiological activity, such as transcriptional regulation, anti-oxidative stress and tumor formation. In this study, we investigated the effects of DJ-1 on hypoxia-induced PAH model rats and PASMCs, as well as its possible molecular mechanism. First, the low expressions of DJ-1 and caveolin-1 (Cav-1) were synchronously detected in lung tissue of PAH model rats and hypoxia-induced PASMCs by Western blot. Then, the DJ-1 wild type (WT) or Knock out (KO) rats were exposed to chronic hypoxia to mimic a hypoxic PAH condition. The protein level of Cav-1 was markedly decreased in the tissue of DJ-1 KO rats, and additionally lower in tissue of the hypoxia group than that in the normoxia group for DJ-1 WT and KO rats. In vivo, hemodynamic data showed that the pulmonary arterial pressure (mPAP), right ventricle systolic pressure (RVSP) and pulmonary arterial systolic pressure (PASP), as well as the weight of the right ventricle/left ventricle plus septum (RV/LV+S) ratio of PAH model rats were higher in the DJ-1 KO group than those in the DJ-1 WT group. Moreover, knockout of DJ-1 also results in the phenotype switch from contractile to synthetic PASMC, which is reflected by reduced calponin and SM22α expressions. In vitro, DJ-1 overexpression reversed hypoxia-induced elevation of PASMC cell proliferation, migration and Ca²⁺ concentration, which were not obviously observed in Cav-1 shRNA (sh-Cav-1) and DJ-1 co-transfected cells. Then the increased levels of calponin and SM22α were detected in the DJ-1 group; similarly those levels were not changed in the DJ-1+sh-Cav-1 group. Finally, the expression of TGFβ1, p-Smad2 and p-Smad3 were obviously decreased in the ad-DJ-1 group, however those were all elevated in the DJ-1 and sh-Cav-1 co-transfected groups. In conclusion, these results indicate that DJ-1 may alleviate hypoxia-induced PASMCs injury by Cav-1 through inhibiting the TGFβ/Smad signaling pathway.

Low-power laser irradiation inhibits PDGF-BB-induced migration and proliferation via apoptotic cell death in vascular smooth muscle cells

Vascular restenosis after injury of blood vessel has been implicated in various responses including apoptosis, migration, and proliferation in vascular smooth muscle cells (VSMCs) stimulated by diverse growth factors underlying platelet-derived growth factor (PDGF). Previous studies evaluated the effects of low-power laser (LPL) irradiation over various wavelength ranges on VSMC events in normal and pathologic states. However, whether VSMC responses are affected by LPL irradiation remains unclear. The purpose of this study is to explore the effects of LPL (green diode laser 532-nm pulsed wave of 300 mW at a spot diameter of 1 mm) irradiation on the responses, apoptosis, migration, and proliferation of VSMCs. The effect of LPL irradiation was tested on VSMCs through cytotoxicity, proliferation, migration, and apoptotic assays. Aortic ring assay was used to assess the effect of LPL irradiation on aortic sprout outgrowth. Protein expression levels were determined by western blotting. LPL irradiation did not affect VSMC viability but slightly attenuated PDGF-BB-induced proliferation in VSMCs. In addition, LPL irradiation inhibited PDGF-BB-evoked migration of VSMCs. Aortic sprout outgrowth in response to PDGF-BB was diminished in cells treated with LPL. In contrast, LPL irradiation evoked apoptosis in VSMCs in the presence of PDGF-BB. Similarly, activation of caspase-3 and Bax, as well as p38 mitogen-activated protein kinase (MAPK), in VSMCs treated with PDGF-BB was enhanced by exposure to LPL. These findings indicate that LPL irradiation induces vascular apoptosis via p38 MAPK activation and simultaneously inhibits VSMC proliferation and migration in response to PDGF-BB.

The inhibitory effect of Isoliquiritigenin on the proliferation of human arterial smooth muscle cell

BACKGROUND

Isoliquiritigenin (ISL) has various biological activities including as antioxidant and an inhibitor of PI3K/AKT signaling pathway. However, both oxidative stress and activated PI3K/AKT signaling contribute to the aberrant proliferation of vascular smooth muscle cells (VSMCs). This study is aimed to explore the effect of ISL on the proliferation of human arterial smooth muscle cells (HASMCs) and to investigate the underlying mechanisms.

METHODS

BrdU incorporation, cell cycle and reactive oxygen species (ROS) in normal or ISL treated HASMCs were analyzed by flow cytometry. Cell viablity was measured by CCK-8. Protein expression levels were examined by Western blot, and superoxide dismutase (SOD) activity was detected by using commercial kit.

RESULTS

We observed that ISL could inhibit the proliferation of HASMCs in a dose and time dependent manner. Cell cycle of ISL treated HASMCs arrested mainly in G1/S phase and accompanied with elevated expression of p27 and decreased expression of CyclinD1 and CyclinE. In addition, ISL could down-regulated the expression of p-PI3K and p-AKT, alleviated oxidative stress and enhanced the SOD activity in HASMCs. Furthermore, H₂O₂ treatment partly improved cell viability and up regulated p-PI3K and p-AKT in HASMCs.

CONCLUSIONS

Therefore, we concluded that ISL inhibited the proliferation of HASMCs via attenuating oxidative stress and suppressing PI3K/AKT signaling pathway. The inhibitory effect of ISL on PI3K/AKT signaling pathway, at least partly, was mediated by ROS.

DJ-1 Is Upregulated in Oral Squamous Cell Carcinoma and Promotes Oral Cancer Cell Proliferation and Invasion

Background: The development of oral squamous cell carcinoma (OSCC) is a multistep process that involves in both genetic alterations and epigenetic modifications. DJ-1, a negative regulator of tumor suppressor PTEN, functions as an oncogene in many types of cancers. However, its role in OSCC is poorly known.

Methods: Immunohistochemical staining and Western blotting were performed to evaluate the expression level of DJ-1 in oral leukoplakia (OLK) and OSCC tissues respectively. Then lentiviral mediated DJ-1 shRNA was constructed and used to infect the OSCC cell lines (Tca8113 and CAL-27). MTT, cell counting, and Matrigel invasion assay were utilized to examine the effects of DJ-1 down-regulation on proliferation and invasion capacity of oral cancer cells.

Results: The immunoreactivity and expression level of DJ-1 protein was significantly increased in OLK and OSCC tissues compared with the controls. Lentiviral-delivered shRNA targeting DJ-1 could effectively knock down DJ-1 at mRNA and protein level (P<0.01). The proliferative and invasion ability of OSCC cell lines was significantly suppressed following DJ-1 inhibition (P<0.01).

Conclusions: Our study indicated that DJ-1 is over-expressed in both oral precancer and cancer tissues and shRNA inhibition of DJ-1 expression led to decreased proliferation and invasion capability of oral cancer cells. These findings suggest that DJ-1 might be actively involved in the development of OSCC. Future studies will investigate the potential of DJ-1 as a biomarker for early detection of OSCC.

PPARγ Inhibits VSMC Proliferation and Migration via Attenuating Oxidative Stress through Upregulating UCP2

Increasing evidence showed that abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are common event in the pathophysiology of many vascular diseases, including atherosclerosis and restenosis after angioplasty. Among the underlying mechanisms, oxidative stress is one of the principal contributors to the proliferation and migration of VSMCs. Oxidative stress occurs as a result of persistent production of reactive oxygen species (ROS). Recently, the protective effects of peroxisome proliferator-activated receptor γ (PPARγ) against oxidative stress/ROS in other cell types provide new insights to inhibit the suggests that PPARγ may regulate VSMCs function. However, it remains unclear whether activation of PPARγ can attenuate oxidative stress and further inhibit VSMC proliferation and migration. In this study, we therefore investigated the effect of PPARγ on inhibiting VSMC oxidative stress and the capability of proliferation and migration, and the potential role of mitochondrial uncoupling protein 2 (UCP2) in oxidative stress. It was found that platelet derived growth factor-BB (PDGF-BB) induced VSMC proliferation and migration as well as ROS production; PPARγ inhibited PDGF-BB-induced VSMC proliferation, migration and oxidative stress; PPARγ activation upregulated UCP2 expression in VSMCs; PPARγ inhibited PDGF-BB-induced ROS in VSMCs by upregulating UCP2 expression; PPARγ ameliorated injury-induced oxidative stress and intimal hyperplasia (IH) in UCP2-dependent manner. In conclusion, our study provides evidence that activation of PPARγ can attenuate ROS and VSMC proliferation and migration by upregulating UCP2 expression, and thus inhibit IH following carotid injury. These findings suggest PPARγ may represent a prospective target for the prevention and treatment of IH-associated vascular diseases.

DJ-1 protects against undernutrition-induced atrophy through inhibition of the MAPK-ubiquitin ligase pathway in myoblasts

AIMS

The purpose of this study is to explore whether antioxidant DJ-1 protein affects the atrophy of skeletal muscle cell induced by undernutrition.

MAIN METHODS

To determine cell atrophic responses, L6 cell line and skeletal primary cells from mouse hind limbs were cultivated under condition of FBS-free and low glucose. Changes of protein expression were analyzed using Western blot. Overexpression and knockdown of DJ-1 was performed in cells to assess its influence on cell atrophic responses.

KEY FINDINGS

Undernutrition decreased cell size and increased the abundance of oxidized form and total form of DJ-1 protein in L6 myoblasts. The undernourished cells revealed an elevation in the expression of muscle-specific RING finger-1 (MuRF-1) and atrogin-1, and in the phosphorylations of p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase/c-Jun N-terminal kinase compared with control groups. Moreover, DJ-1-knockout mice showed a decrease in cell size and an enhancement in the expression of MuRF-1 and atrogin-1, as well as in the phosphorylation of MAPKs in gastrocnemius muscles; these changes were also observed in L6 cells transfected with siRNA of DJ-1. On the other hand, L6 cells overexpressing full-length DJ-1 did not exhibit the alterations in cell size and ubiquitin ligases seen after undernourished states of control cells. Myotubes differentiated from L6 cells also showed elevated expression of MuRF-1 and atrogin-1 in response to undernutrition.

SIGNIFICANCE

These results suggest that DJ-1 protein may contribute to undernutrition-induced atrophy via MAPKs/ubiquitin ligase pathway in skeletal muscle cells.

The serum protein fetuin-B is involved in the development of acute myocardial infarction

Fetuin-B was one of highly expressed serum proteins in AMI compared with stable angina. This protein affected vascular plaque-stabilizing components in monocytes, macrophages and vascular smooth muscle cells. Fetuin-B may be a possible contributor to AMI.

Carvacrol inhibits atherosclerotic neointima formation by downregulating reactive oxygen species production in vascular smooth muscle cells

OBJECTIVE

Carvacrol (2-methyl-5-(1-methylethyl) phenol), a cyclic monoterpene, exerts protective activities in a variety of pathological states including tumor growth, inflammation, and oxidative stress. However, it is unknown whether carvacrol affects events in vascular cells during the development of atherosclerotic neointima. We investigated the effects of carvacrol on the migration and proliferation of rat aortic smooth muscle cells (RASMCs) and on vascular neointima formation.

METHODS AND RESULTS

Carvacrol significantly inhibited platelet-derived growth factor (PDGF)-BB-stimulated RASMC migration and proliferation in a concentration-dependent manner. Cell viability was not affected by treatment with carvacrol. Carvacrol attenuated the expression of NADPH oxidase (NOX) 1 and the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase 1/2 in response to PDGF-BB. Moreover, carvacrol suppressed the PDGF-BB-stimulated generation of H2O2 and inhibited the activity of NOX in RASMCs. Treatment with carvacrol inhibited PDGF-BB-induced aortic sprout outgrowth, balloon injury-evoked vascular neointima formation, and expression of proliferating cell nuclear antigen in the neointima.

CONCLUSION

These findings indicate that carvacrol inhibits migration and proliferation of RASMCs by suppressing the reactive oxygen species-mediated MAPK signaling pathway in these cells, thereby attenuating vascular neointimal formation. Carvacrol may be a promising agent for preventing vascular restenosis or atherosclerosis.

Nobiletin Inhibits PDGF-BB-induced vascular smooth muscle cell proliferation and migration and attenuates neointimal hyperplasia in a rat carotid artery injury model

Preclinical Research The abnormal migration and proliferation of vascular smooth muscle cells (VSMCs) plays a pivotal role in the development of neointimal hyperplasia after vascular injury. Nobiletin, a citrus bioflavonoid, exhibits anti-inflammatory and anti-oxidative activities. The present study evalutaed whether nobiletin could inhibit platelet-derived growth factor (PDGF)-BB- stimulated VSMC proliferation and migration and decrease neointimal hyperplasia in a rat carotid artery injury model. Cultured VSMCs from rat thoracic aortas were treated with nobiletin before being stimulated with 20 ng/ml PDGF-BB, and rats were subjected to carotid artery injury. Nobiletin inhibited PDGF-BB-induced VSMC proliferation and migration, attenuated reactive oxygen species (ROS) production and reduced phosphorylation of ERK1/2 and the expression of nuclear NF-κB p65 in PDGF-BB-stimulated VSMCs. Nobiletin decreased the intima area and the ratio of neointima to media in balloon-injured rat carotid arteries. Serum levels of TNF-α and IL-6 in nobiletin-treated rats were decreased. These results indicated that nobiletin could be a potential protective agent for the prevention and treatment of restenosis after angioplasty.

DJ-1 regulates the expression of renal (pro)renin receptor via reactive oxygen species-mediated epigenetic modification

BACKGROUND

DJ-1 protein plays multifunctional roles including transcriptional regulation and scavenging oxidative stress; thus, it may be associated with the development of renal disorders. We investigated whether DJ-1 protein regulates the expression of (pro)renin receptor (PRR), a newly identified member of renin-angiotensin system.

METHODS

The levels of mRNA and protein were determined by real-time PCR and western blot, respectively. H2O2 production was tested by using fluorescence probe. Histone modification was determined by chromatin immunoprecipitation.

RESULTS

The expression of PRR was significantly higher in the kidney from DJ-1 knockout mice (DJ-1-/-) compared with wild-type mice (DJ-1+/+). Histone deacetylase 1 recruitment at the PRR promoter was lower, and histone H3 acetylation and RNA polymerase II recruitment were higher in DJ-1-/- than in DJ-1+/+. Knockdown or inhibition of histone deacetylase 1 restored PRR expression in mesangial cells from DJ-1+/+. H2O2 production was greater in DJ-1-/- cells compared with DJ-1+/+ cells. These changes in PRR expression and epigenetic modification in DJ-1-/- cells were induced by H2O2 treatment and reversed completely by addition of an antioxidant reagent. Prorenin-stimulated ERK1/2 phosphorylation was greater in DJ-1-/- than in DJ-1+/+ cells and this was inhibited by a PRR-inhibitory peptide, and by AT1 and AT2 receptor inhibitors. The expression of renal fibrotic genes was higher in DJ-1-/- than in DJ-1+/+ cells and decreased in PRR-knockdown DJ-1-/- cells.

CONCLUSIONS

We conclude that DJ-1 protein regulates the expression of renal PRR through H2O2-mediated epigenetic modification.

GENERAL SIGNIFICANCE

We suggest that renal DJ-1 protein may be an important molecule in the acceleration of renal pathogenesis through PRR regulation.

DJ-1 protein regulates CD3+ T cell migration via overexpression of CXCR4 receptor

OBJECTIVE

DJ-1-a multifunctional protein responding to oxidative stress-is a possible regulator of the inflammatory response that plays an important role in atherosclerosis. Stromal cell-derived factor (SDF)-1 and its receptor, chemokine receptor type 4 (CXCR4), have been implicated in the recruitment of inflammatory cells during atherosclerosis. Here we investigated the hypothesis that DJ-1 protein might participate in CD3+ T cell functions in response to SDF-1 and contribute to the pathogenesis of atherosclerosis.

METHODS AND RESULTS

SDF-1 stimulated migration in mouse CD3+ T cells in a dose-dependent manner. SDF-1 also elevated the phosphorylation level of extracellular-regulated kinase (ERK) 1/2 in CD3+ T cells. These SDF-1-induced responses were greater in CD3+ T cells from DJ-1 gene knockout (DJ-1(-/-)) mice than in those from wild type (DJ-1(+/+)) mice and were abolished by treatment with WZ811 and PD98059, inhibitors of CXCR4 and ERK1/2, respectively. Flow cytometry revealed that expression of the CXCR4 receptor was greater in CD3+ T cells from DJ-1(-/-) mice than in those from the controls. Moreover, expression of the CD3 protein was observed in the neointimal plaque from carotid artery-ligated mice and was stronger in DJ-1(-/-) mice compared with controls. The CD3+ T cell subsets, Th1 and Th17, showed increased production of interferon-γ and interleukin-17 in DJ-1(-/-) compared with DJ-1(+/+) mice.

CONCLUSION

DJ-1 protein is involved in the SDF-1-induced CD3+ T cell migration via overexpression of the CXCR4 receptor, and that DJ-1 acts as an inhibitory regulator in vascular remodeling such as neointima formation.

DJ-1/park7 modulates vasorelaxation and blood pressure via epigenetic modification of endothelial nitric oxide synthase

AIMS

DJ-1/park7, a multifunctional protein, may play essential roles in the vascular system. However, the function of DJ-1/park7 in vascular contractility has remained unclear. The present study was designed to investigate whether the DJ-1/park7 is involved in the regulation of vascular contractility and systolic blood pressure (SBP).

METHODS AND RESULTS

Norepinephrine (NE) elevated contraction in endothelium-intact vessels in a dose-dependent manner, to a greater extent in DJ-1/park7 knockout (DJ-1/park7(-/-)) mice than in wild-type (DJ-1/park7(+/+)) mice. Acetylcholine inhibited NE-evoked contraction in endothelium-intact vessels, and this was markedly impaired in DJ-1/park7(-/-) mice compared with DJ-1/park7(+/+). Nitric oxide (NO) production (82.1 ± 2.8% of control) and endothelial NO synthase (eNOS) expression (61.7 ± 8.9%) were lower, but H2O2 production (126.4 ± 8.6%) was higher, in endothelial cells from DJ-1/park7(-/-) mice than in those from DJ-1/park7(+/+) controls; these effects were reversed by DJ-1/park7-overexpressing endothelial cells from DJ-1/park7(-/-) mice. Histone deacetylase (HDAC)-1 recruitment and H3 histone acetylation at the eNOS promoter were elevated and diminished, respectively, in DJ-1/park7(-/-) mice compared with DJ-1/park7(+/+) controls. Moreover, SBP was significantly elevated in DJ-1/park7(-/-) mice compared with DJ-1/park7(+/+) controls, but this elevation was inhibited in mice treated with valproic acid, an inhibitor of Class I HDACs including HDAC-1.

CONCLUSION

These results demonstrate that DJ-1/park7 protein may be implicated in the regulation of vascular contractility and blood pressure, probably by the impairment of NO production through H2O2-mediated epigenetic inhibition of eNOS expression.

Evidence of oxidative stress in young and aged DJ-1-deficient mice

Loss of DJ-1 function contributes to pathogenesis in Parkinson's disease. Here, we investigate the impact of aging and DJ-1 deficiency in transgenic mice. Ventral midbrain from young DJ-1-deficient mice revealed no change in 4-hydroxy-2-nonenal (4-HNE), but HSP60, HSP40 and striatal dopamine turnover were significantly elevated compared to wildtype. In aged mice, the chaperone response observed in wildtype animals was absent from DJ-1-deficient transgenics, and nigral 4-HNE immunoreactivity was enhanced. These changes were concomitant with increased striatal dopamine levels and uptake. Thus, increased oxidants and diminished protein quality control may contribute to nigral oxidative damage with aging in the model.