Delivery of Superoxide Dismutase 3 Gene with Baculoviruses Inhibits TNF-α Triggers Vascular Smooth Muscle Cell Proliferation and Inflammation.

BACKGROUND: Superoxide dismutase 3 (SOD3), recognized as a potent free radical scavenger, exhibits antioxidant, anti-inflammatory, and anti-angiogenic properties. However, the molecular mechanisms underlying the protective effects of SOD3 on the vascular smooth muscle cell during atherosclerosis remain unclear. OBJECTIVES: This study aimed to investigate the efficacy of the baculovirus expressing SOD3 gene delivery to vascular smooth muscle cells (VSMCs) and investigate whether the overexpression of SOD3 mitigates cell proliferation and migration induced by tumor necrosis factor-α (TNF-α). METHODS: A baculoviral vector containing SOD3 cDNA (vAcMBac-CMV-IE-SOD3) was constructed and utilized to deliver the SOD3 gene into primary rat VSMCs. Cells were stimulated with recombinant TNF-α, and then cell proliferation and migration were evaluated using the bromodeoxyuridine and wound healing assay. Western blot was used to verify the expression of cell cycle regulators, cellular mediators, and proliferative biomarkers. Zymography, immunofluorescence staining, and ELISA assay were conducted to assess the expression levels of matrix metalloproteinases. RESULTS: The results demonstrated efficient and non-cytotoxic transduction of vAcMBac- CMV-IE-SOD3 in VSMCs. SOD3 overexpression significantly suppressed cell proliferation and motility by inhibiting cell cycle regulators in TNF-α-induced cells. TNF-α elevated protein levels of phospho-ERK and phospho-Akt were reduced markedly by SOD3-overexpressing. Additionally, SOD3 overexpression attenuated the elevation of MMP-2 and MMP-9, the pro-inflammatory and proliferative biomarkers. Overall, the SOD3 gene delivery exhibited potent anti-proliferation and anti-inflammation effects on TNF-α-induced VSMCs. CONCLUSION: An effective SOD3 gene delivery using a recombinant baculoviral vector has been successfully established and is useful for overexpression of the SOD gene family. This approach provides new therapeutic strategies in gene therapy against atherosclerosis.

Pharmacogenomics and circadian rhythms as mediators of cardiovascular drug-drug interactions.

This article summarizes the current literature and documents new evidence concerning drug-drug interactions (DDI) stemming from pharmacogenomic and circadian rhythm determinants of therapies used to treat common cardiovascular diseases (CVD), such as atherosclerosis and hypertension. Patients with CVD often have more than one pathophysiologic condition, namely metabolic syndromes, hypertension, hyperlipidemia, and hyperglycemia, among others, which necessitate polytherapeutic or polypharmaceutic management. Interactions between drugs, drugs and food/food supplements, or drugs and genetic/epigenetic factors may have adverse impacts on the cardiovascular and other systems of the body. The mechanisms underlying cardiovascular DDI may involve the formation of a complex pharmacointeractome, including the absorption, distribution, metabolism, and elimination of drugs, which affect their respective bioavailability, efficacy, and/or harmful metabolites. The pharmacointeractome of cardiovascular drugs is likely operated with endogenous rhythms controlled by circadian clock genes. Basic and clinical investigations have improved the knowledge and understanding of cardiovascular pharmacogenomics and pharmacointeractomes, and additionally they have presented new evidence that the staging of deterministic circadian rhythms, according to the dosing time of drugs, e.g., upon awakening vs. at bedtime, cannot only differentially impact their pharmacokinetics and pharmacodynamics but also mediate agonistic/synergetic or antagonistic DDI. To properly manage CVD patients and avoid DDI, it is important that clinicians have sufficient knowledge of their multiple risk factors, i.e., age, gender, and life style elements (like diet, smoking, psychological stress, and alcohol consumption), and comorbidities, such as diabetes, hypertension, dyslipidemia, and depression, and the potential interactions between genetic or epigenetic background of their prescribed therapeutics.

Telomerase/myocardin expressing mesenchymal cells induce survival and cardiovascular markers in cardiac stromal cells undergoing ischaemia/reperfusion.

Cardiac stromal cells (CSCs) contain a pool of cells with supportive and paracrine functions. Various types of mesenchymal stromal cells (MSCs) can influence CSCs in the cardiac niche through their paracrine activity. Ischaemia/reperfusion (I/R) leads to cell death and reduction of the paracrine activity of CSCs. The forced co-expression of telomerase reverse transcriptase (TERT) and myocardin (MYOCD), known to potentiate anti-apoptotic, pro-survival and pro-angiogenic activities of MSCs isolated from the adipose tissue (AT-MSCs), may increase CSC survival, favouring their paracrine activities. We aimed at investigating the hypothesis that CSCs feature improved resistance to simulated I/R (SI/R) and increased commitment towards the cardiovascular lineage when preconditioned with conditioned media (CM) or extracellular vesicles (EV) released from AT-MSCs overexpressing TERT and MYOCD (T/M AT-MSCs). Murine CSCs were isolated with the cardiosphere (CSps) isolation technique. T/M AT-MSCs and their secretome improved spontaneous intracellular calcium changes and ryanodine receptor expression in aged CSps. The cytoprotective effect of AT-MSCs was tested in CSCs subjected to SI/R. SI/R induced cell death as compared to normoxia (28 ± 4 vs 10 ± 3%, P = .02). Pre-treatment with CM (15 ± 2, P = .02) or with the EV-enriched fraction (10 ± 1%, P = .02) obtained from mock-transduced AT-MSCs in normoxia reduced cell death after SI/R. The effect was more pronounced with CM (7 ± 1%, P = .01) or the EV-enriched fraction (2 ± 1%, P = .01) obtained from T/M AT-MSCs subjected to SI/R. In parallel, we observed lower expression of the apoptosis marker cleaved caspase-3 and higher expression of cardiac and vascular markers eNOS, sarcomeric α-actinin and cardiac actin. The T/M AT-MSCs secretome exerts a cytoprotective effect and promotes development of CSCs undergoing SI/R towards a cardiovascular phenotype.

Transplantation of telomerase/myocardin-co-expressing mesenchymal cells in the mouse promotes myocardial revascularization and tissue repair.

AIM: Cell therapies are hampered by poor survival and growth of grafts. We tested whether forced co-expression of telomerase reverse transcriptase (TERT) and myocardin (MYOCD) improves post-infarct revascularization and tissue repair by adipose tissue-derived mesenchymal stromal cells (AT-MSCs). METHODS AND RESULTS: We transplanted AT-MSCs overexpressing MYOCD and TERT in a murine model of acute myocardial infarction (AMI). We characterized paracrine effects of AT-MSCs. When transplanted into infarcted hearts of C57BL/6 mice, AT-MSCs overexpressing TERT and MYOCD decreased scar tissue and the intra-scar CD3 and B220 lymphocyte infiltration; and increased arteriolar density as well as ejection fraction compared with saline or mock-transduced AT-MSCs. These effects were accompanied by higher persistence of the injected cells in the heart, increased numbers of Ki-67+ and CD117+ cells, and the expression of cardiac actin and ß-myosin heavy chain. Intramyocardial delivery of the secretome and its extracellular vesicle (EV)-enriched fraction also decreased scar tissue formation and increased arteriolar density in the murine AMI model. Proteomic analysis of AT-MSCs-EV-enriched fraction predicted the activation of vascular development and the inhibition of immune cell trafficking. Elevated concentrations of miR-320a, miR-150-5p and miR-126-3p associated with regulation of apoptosis and vasculogenesis were confirmed in the AT-MSCs-EV-enriched fraction. CONCLUSIONS: AT-MSCs overexpressing TERT and MYOCD promote persistence of transplanted aged AT-MSCs and enhance arteriolar density in a murine model of AMI. EV-enriched fraction is the component of the paracrine secretion by AT-MSCs with pro-angiogenic and anti-fibrotic activities.

Strengthening effects of bone marrow mononuclear cells with intensive atorvastatin in acute myocardial infarction.

OBJECTIVE: To test whether intensive atorvastatin (ATV) increases the efficacy of transplantation with autologous bone marrow mononuclear cells (MNCs) in patients suffering from anterior ST-elevated myocardial infarction (STEMI). METHODS: This clinical trial was under a 2×2 factorial design, enrolling 100 STEMI patients, randomly into four groups of regular (RA) or intensive ATV (IA) with MNCs or placebo. The primary endpoint was the change of left ventricular ejection fraction (LVEF) at 1-year follow-up from baseline, primarily assessed by MRI. The secondary endpoints included other parameters of cardiac function, remodelling and regeneration determined by MRI, echocardiography, positron emission tomography (PET) and biomarkers. RESULTS: All the STEMI patients with transplantation of MNCs showed significantly increased LVEF change values than those with placebo (p=0.01) with only in the IA+MNCs patients group demonstrating significantly elevation of LVEF than in the IA+placebo group (+12.6% (95%CI 10.4 to 19.3) vs +5.0% (95%CI 4.0 to 10.0), p=0.001), pointing to a better synergy between ATV and MNCs (p=0.019). PET analysis revealed significantly increased viable areas of myocardium (p=0.015), while the scar sizes (p=0.026) and blood aminoterminal pro-B-type natriuretic peptide (p<0.034) reduced. All these above benefits of MNCs were also attributed to IA+MNCs instead of RA+MNCs group of patients with STEMI. CONCLUSIONS: Intensive ATV treatment augments the therapeutic efficacy of MNCs in patients with anterior STEMI at the convalescent stage. The treatment with the protocol of intensive ATV and MNC combination offers a clinically essential approach for myocardial infarction. TRIAL REGISTRATION NUMBER: NCT00979758.

Pathophysiological characteristics and therapeutic approaches for pulmonary injury and cardiovascular complications of coronavirus disease 2019.

The pandemic of coronavirus disease 2019 (COVID-19) has emerged as a major health crisis, with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) having infected over a million people around the world within a few months of its identification as a human pathogen. Initially, SARS-CoV-2 infects cells in the respiratory system and causes inflammation and cell death. Subsequently, the virus spreads out and damages other vital organs and tissues, triggering a complicated spectrum of pathophysiological changes and symptoms, including cardiovascular complications. Acting as the receptor for SARS-CoV entering mammalian cells, angiotensin converting enzyme-2 (ACE2) plays a pivotal role in the regulation of cardiovascular cell function. Diverse clinical manifestations and laboratory abnormalities occur in patients with cardiovascular injury in COVID-19, characterizing the development of this complication, as well as providing clues to diagnosis and treatment. This review provides a summary of the rapidly appearing laboratory and clinical evidence for the pathophysiology and therapeutic approaches to COVID-19 pulmonary and cardiovascular complications.

Estrogen inhibits vascular calcification in rats via hypoxia-induced factor-1α signaling.

OBJECTIVE: Calcification serves as a surrogate for atherosclerosis-associated vascular diseases, and coronary artery calcification is mediated by multiple pathogenic factors. Estrogen is a known factor that protects the arterial wall against atherosclerosis, but its role in the coronary artery calcification development remains largely unclear. This study tested the hypothesis that estrogen inhibits coronary artery calcification via the hypoxia-induced factor-1α pathway. METHODS: Eight-week-old healthy female Sprague-Dawley rats were castrated, and vitamin D3 was administered orally to establish. Hypoxia-induced factor-1 inhibitor was administered to test its effect on vascular calcification and expression of bone morphogenetic protein 2 and runt-related transcription factor-2. Vascular smooth muscle cell calcification was induced with CaCl2 in rat aortic smooth muscle cells in the presence or absence of E2(17ß-estradiol) and bone morphogenetic protein 2 siRNA intervention. RESULTS: The estrogen levels in ovariectomized rats were significantly decreased, as determined by ELISA. Expression of hypoxia-induced factor-1α mRNA and protein was significantly increased in vascular cells with calcification as compared to those without calcification (p < 0.01). E2 treatment decreased the calcium concentration in vascular cell calcification and cell calcium nodules in vitro (p < 0.05). E2 also lowered the levels of hypoxia-induced factor-1α mRNA and protein (p < 0.01). Oral administration of the hypoxia-induced factor-1α inhibitor dimethyloxetane in castrated rats alleviated vascular calcification and expression of osteogenesis-related transcription factors, bone morphogenetic protein 2 and RUNX2 (p < 0.01). Finally, bone morphogenetic protein 2 siRNA treatment decreased the levels of p-Smad1/5/8 in A7r5 calcification cells (p < 0.01). CONCLUSION: Estrogen deficiency enhances vascular calcification. Treatment with estrogen reduces the expression of hypoxia-induced factor-1α as well as vascular calcification in rats. The estrogen effects occur in a fashion dependent on hypoxia-induced factor-1α regulation of bone morphogenetic protein-2 and downstream Smad1/5/8.

Differential expression of microRNA and arachidonic acid metabolism in aspirin-treated human cardiac and peri-cardiac fat-derived mesenchymal stem cells.

Aspirin is a widely used drug with anti-coagulating and anti-inflammatory effects on atherosclerotic vascular disease. The goal of this study was to investigate expression of microRNA (miR) in association with changes in arachidonic acid (AA) metabolism in cardiac and surrounding fat mesenchymal stem cells (MSCs) treated with or without aspirin. Aspirin-targeted endogenous lipid metabolites that impact specific miRNA expression were examined by mass spectrometry. The pattern of miR expression was characterized using a microarray of 1100 miRs. There were a dozen miRs expressed differentially in MSCs from human myocardium and peri-myocardial fat tissue at baseline, including hsa-miR-1307-3p, 765, 4739, 3613-3p, 4281, 6816-5p, 2861, and 146b-5p. After exposure to aspirin, cardiac MSCs expressed an array of of miRs (eg, hsa-miR-4734, 10a-5p, 4267, 3197, and 3182), while generation of their endogenous AA metabolites was depressed. However, in the peri-cardiac adipose tissue-derived MSCs, treatment with the same doses of aspirin caused mild changes in the miR expression levels. In conclusion, MSCs from human myocardium and peri-myocardial fat tissue respond differentially to aspirin treatment by alterations in miR expression and AA metabolism. The study further raises an intriguing issue as to whether the copious amounts of aspirin taken worldwide by patients with cardiovascular disease may have direct impacts on their heart repair processes by regulation of stromal cell miR expression and AA metabolism.

Transplantation efficacy of autologous bone marrow mesenchymal stem cells combined with atorvastatin for acute myocardial infarction (TEAM-AMI): rationale and design of a randomized, double-blind, placebo-controlled, multi-center, Phase II TEAM-AMI trial.

Aim: To determine the efficacy and safety of intracoronary infusion of autologous bone marrow mesenchymal stem cells (MSCINJ) in combination with intensive atorvastatin (ATV) treatment for patients with anterior ST-segment elevation myocardial infarction-elevation myocardial infarction. Patients & methods: The trial enrolls a total of 100 patients with anterior ST-elevation myocardial infarction. The subjects are randomly assigned (1:1:1:1) to receive routine ATV (20 mg/d) with placebo or MSCsINJ and intensive ATV (80 mg/d) with placebo or MSCsINJ. The primary end point is the absolute change of left ventricular ejection fraction within 12 months. The secondary end points include parameters in cardiac function, remodeling and regeneration, quality of life, biomarkers and clinical outcomes. Results & conclusion: The trial will implicate the essential of cardiac micro-environment improvement ('fertilizing') for cell-based therapy. Clinical Trial Registration: NCT03047772.

Inhibition of Neointima Hyperplasia, Inflammation, and Reactive Oxygen Species in Balloon-Injured Arteries by HVJ Envelope Vector-Mediated Delivery of Superoxide Dismutase Gene.

Extracellular superoxide dismutase (EC-SOD) has been implicated in regulation of vascular function but its underlying molecular mechanism is largely unknown. These two-step experiments investigate whether hemagglutinating virus of Japan envelope (HVJ-E) vector-mediated EC-SOD gene delivery might protect against neointima formation, vascular inflammation, and reactive oxygen species (ROS) generation, and also explore cell growth signaling pathways. The first in-vitro experiment was performed to assess the transfection efficacy and safety of HVJ-E compared to lipofectamine®. Results revealed that HVJ-E has higher transfection efficiency and lower cytotoxicity than those of lipofectamine®. Another in-vivo study initially used balloon denudation to rat carotid artery, then delivered EC-SOD cDNA through the vector of HVJ-E. Arterial section with H&E staining from the animals 14 days after balloon injury showed a significant reduction of intima-to-media area ratio in EC-SOD transfected arteries when compared with control (empty vector-transfected arteries) (p < 0.05). Arterial tissue with EC-SOD gene delivery also exhibited lower levels of ROS, as assessed by fluorescent microphotography with dihydroethidium staining. Quantitative RT-PCR revealed that EC-SOD gene delivery significantly diminished mRNA expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß (p < 0.05 in all comparisons). An immunoblotting assay from vascular smooth muscle cell (VSMC) cultures showed that the EC-SOD transfected group attenuated the activation of MEK1/2, ERK1/2, and Akt signaling significantly. In conclusion, EC-SOD overexpression by HVJ-E vector inhibits neointima hyperplasia, inflammation, and ROS level triggered by balloon injury. The modulation of cell growth-signaling pathways by EC-SOD in VSMCs might play an important role in these inhibitory effects.

Exosomes Derived from Embryonic Stem Cells as Potential Treatment for Cardiovascular Diseases.

Cardiovascular diseases resulting from ischemic heart diseases remain to be the main causes of heart failure and death despite significant advances in medical treatment. The development of new therapies for heart failure is thus required to improve the outcome in these patients, and this has led to the development of cell-based therapies. Animal studies showed interesting results using various cell types. Some stem cell based therapies have been tested in clinical trials. Although the results were encouraging, challenges remain. Tumorigenic potential, immune rejection, and low engraftment and survival rate of transplant cells have hindered the widespread application of stem cells in the clinic. Fortunately, exosome based therapy could avoid these problems associated with cell therapy. Future research should focus on how various molecules are sorted into exosomes and this information will help to design better exosomes for treatment of cardiovascular diseases. Recent studies suggest that exosome content can vary depending on how cells are challenged. It would be important to find out exactly what types of cellular stress is needed for producing most useful exosomes. Alternatively, specific molecules can be introduced into exosomes by genetic engineering in order to treat specific conditions and to improve efficacy.

Diabetic microangiopathy: Pathogenetic insights and novel therapeutic approaches.

Diabetic microangiopathy, including retinopathy, is characterized by abnormal growth and leakage of small blood vessels, resulting in local edema and functional impairment of the depending tissues. Mechanisms leading to the impairment of microcirculation in diabetes are multiple and still largely unclear. However, a dysregulated vascular regeneration appears to play a key role. In addition, oxidative and hyperosmolar stress, as well as the activation of inflammatory pathways triggered by advanced glycation end-products and toll-like receptors, have been recognized as key underlying events. Here, we review recent knowledge on cellular and molecular pathways of microvascular disease in diabetes. We also highlight how new insights into pathogenic mechanisms of vascular damage in diabetes may indicate new targets for prevention and treatment.

MiRNA-Sequence Indicates That Mesenchymal Stem Cells and Exosomes Have Similar Mechanism to Enhance Cardiac Repair.

Mesenchymal stem cells (MSCs) repair infarcted heart through paracrine mechanism. We sought to compare the effectiveness of MSCs and MSC-derived exosomes (MSC-Exo) in repairing infarcted hearts and to identify how MSC-Exo mediated cardiac repair is regulated. In a rat myocardial infarction model, we found that MSC-Exo inhibited cardiac fibrosis, inflammation, and improved cardiac function. The beneficial effects of MSC-Exo were significantly superior compared to that of MSCs. To explore the potential mechanisms underlying MSC-Exo's effects, we performed several in vitro experiments and miRNA-sequence analysis. MSC-Exo stimulated cardiomyocyte H9C2 cell proliferation, inhibited apoptosis induced by H2O2, and inhibited TGF-ß induced transformation of fibroblast cell into myofibroblast. Importantly, novel miRNA sequencing results indicated that MSC-Exo and MSCs have similar miRNA expression profile, which could be one of the reasons that MSC-Exo can replace MSCs for cardiac repair. In addition, the expression of several miRNAs from MSC-Exo was significantly different from that of MSCs, which may explain why MSC-Exo has better therapeutic effect than MSCs. In conclusion, this study demonstrates that MSC-Exo could be used alone to promote cardiac repair and are superior to MSCs in repairing injured myocardium.

Inhibition of Gata4 and Tbx5 by Nicotine-Mediated DNA Methylation in Myocardial Differentiation.

Maternal nicotine exposure causes alteration of gene expression and cardiovascular programming. The discovery of nicotine-medicated regulation in cardiogenesis is of major importance for the study of cardiac defects. The present study investigated the effect of nicotine on cardiac gene expression and epigenetic regulation during myocardial differentiation. Persistent nicotine exposure selectively inhibited expression of two cardiac genes, Tbx5 and Gata4, by promoter DNA hypermethylation. The nicotine-induced suppression on cardiac differentiation was restored by general nicotinic acetylcholine receptor inhibition. Consistent results of Tbx5 and Gata4 gene suppression and cardiac function impairment with decreased left ventricular ejection fraction were obtained from in vivo studies in offspring. Our results present a direct repressive effect of nicotine on myocardial differentiation by regulating cardiac gene suppression via promoter DNA hypermethylation, contributing to the etiology of smoking-associated cardiac defects.

Pax8 plays a pivotal role in regulation of cardiomyocyte growth and senescence.

Congenital heart disease (CHD) is a worldwide health problem, particularly in young populations. In spite of the advancement and progress in medical research and technology, the underlying causative factors and mechanisms of CHD still remain unclear. Bone morphogenetic protein receptor IA (ALK3) mediates the development of ventricular septal defect (VSD). We have recently found that paired box gene 8 (Pax8) may be the downstream molecule of ALK3. Paired box gene 8 plays an essential role in VSD, and apoptosis and proliferation imbalance leads to septal dysplasia. Recent studies have also disclosed that cellular senescence also participates in embryonic development. Whether programmed senescence exists in cardiac organogenesis has not ever been reported. We hypothesized that together with various biological processes, such as apoptosis, enhanced cellular senescence may occur actively in the development of Pax8 null mice murine hearts. In H9C2 myogenic cells, Pax8 overexpression can rescue caspase-dependent apoptosis induced by ALK3 silencing. Senescent cells and senescence-associated mediators in Pax8 knockout hearts increased compared with the wild-type ones in an age-dependent manner. These results suggest that Pax8 maybe the downstream molecule of ALK3, it mediates the murine heart development perhaps via cellular senescence, which may serve as a mechanism that compensates for the cell loss via apoptosis in heart development.

Epigenetic regulation of insulin-like growth factor signaling: A novel insight into the pathophysiology of neonatal pulmonary hypertension.

Burdened by high morbidity and mortality, neonatal pulmonary hypertension (PH) is a life-threatening pathophysiological condition that progressively elevates the mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR). Pulmonary vascular remodeling and vasoconstriction are recognized pathophysiological features of the disease. Neonatal PH is a serious pathological condition in which persistent PH of the newborn causes hypoxemia and right-to-left extrapulmonary shunting of blood flow, leading to right heart failure and serious life-threatening complications. Recently, the role of growth factors in the pathogenesis of neonatal PH has attracted much attention. Here we provide an update on the ongoing research regarding the epigenetic regulation of the insulin growth factor (IGF)-1/IGF-1 receptor pathway, with insight into the potential regulatory role such regulation in the pathogenesis of neonatal PH.

CD1d serves as a surface receptor for oxidized cholesterol induction of peroxisome proliferator-activated receptor-γ.

OBJECTIVE: The cluster of differentiation-1d (CD1d) recognizes and presents the lipid antigens to NK-T lymphocytes. Atherosclerotic lesions contain atherogenic lipids, mainly cholesterol and its oxides. Peroxisome proliferator-activated receptor-γ (PPARγ) is also known to exist in atherosclerotic lesions, participating in regulation of lipid metabolism. The current study tested whether CD1d acts as a surface receptor that mediates induction and activation of PPARγ by oxysterols commonly found in atherosclerotic lesions. METHODS AND RESULTS: CD1d overexpression in HEK 293 cells transfected with CD1d cDNA was confirmed by fluorescence, flow cytometry, Western blotting and mRNA expression. Tritiated ((3)H) 7-ketocholesterol (7K) was used for lipid binding assays. Radioactive assessment demonstrated an increased 7K-binding activity HEK 293 cells with CD1d overexpression. The 7K binding could be blocked by another oxysterol, 25-hydroxycholesterol, but not by native free cholesterol. Addition of CD1d:IgG dimer protein or an anti-CD1d antibody, but not control IgG, significantly diminished 7K binding to CD1d-expressing HEK 293 cells. CD1d deficiency markedly diminished the 7K-binding in macrophages and smooth muscle cells. Western blot and gel shift assays demonstrated that CD1d-mediated 7K binding induced expression and activation of PPARγ. The PPARγ agonist PGJ2 enhances the 7K stimulatory effect on PPARγ expression and activity but the antagonist GW9662 inhibits the 7K effect on the CD1d-expressing cells. CONCLUSIONS: CD1d acts as a cell surface receptor that recognizes and binds oxysterols and initializes a pathway connecting oxysterol binding to PPARγ activation.

Role of microRNA-29b in angiotensin II-induced epithelial-mesenchymal transition in renal tubular epithelial cells.

Angiotensin II (Ang II) has been proven to induce epithelial-mesenchymal transition (EMT). The aim of the present study was to determine the role of microRNA-29b (miR-29b) during Ang II-induced EMT. For this purpose, we used spontaneously hypertensive rats (SHRs) and age-matched Wistar-Kyoto (WKY) rats. The levels of Ang II and its receptor in the kidneys of the SHRs are significantly higher than those in the age-matched WKY rats. As shown by RT-qPCR, the expression of miR-29b in the renal cortex was lower in the SHRs than in the WKY rats. For in vitro experiments, NRK-52E renal tubular epithelial cells were treated with 10(-7) M Ang II; we found that the expression of miR-29b was decreased in the cells treated with Ang II. In addition, transfection of the NRK-52E cells with miR-29b inhibitor led to the downregulation of miR-29b in these cells, and increased the expression of transforming growth factor (TGF)-ß, α-smooth muscle actin (α-SMA) and collagen I (Col I). Similar results were observed with the induction of Ang II expression in the NRK-52E cells. By contrast, the upregulation of miR-29b by transfection with miR-29b mimics inhibited the overexpression of these genes induced by Ang II. These results suggest that miR-29b plays an important role in Ang II-induced EMT.

Co-activation of nuclear factor-κB and myocardin/serum response factor conveys the hypertrophy signal of high insulin levels in cardiac myoblasts.

Hyperinsulinemia contributes to cardiac hypertrophy and heart failure in patients with the metabolic syndrome and type 2 diabetes. Here, high circulating levels of tumor necrosis factor (TNF)-α may synergize with insulin in signaling inflammation and cardiac hypertrophy. We tested whether high insulin affects activation of TNF-α-induced NF-κB and myocardin/serum response factor (SRF) to convey hypertrophy signaling in cardiac myoblasts. In canine cardiac myoblasts, treatment with high insulin (10(-8) to 10(-7) m) for 0-24 h increased insulin receptor substrate (IRS)-1 phosphorylation at Ser-307, decreased protein levels of chaperone-associated ubiquitin (Ub) E3 ligase C terminus of heat shock protein 70-interacting protein (CHIP), increased SRF activity, as well as ß-myosin heavy chain (MHC) and myocardin expressions. Here siRNAs to myocardin or NF-κB, as well as CHIP overexpression prevented (while siRNA-mediated CHIP disruption potentiated) high insulin-induced SR element (SRE) activation and ß-MHC expression. Insulin markedly potentiated TNF-α-induced NF-κB activation. Compared with insulin alone, insulin+TNF-α increased SRF/SRE binding and ß-MHC expression, which was reversed by the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) and by NF-κB silencing. In the hearts of db/db diabetic mice, in which Akt phosphorylation was decreased, p38MAPK, Akt1, and IRS-1 phosphorylation at Ser-307 were increased, together with myocardin expression as well as SRE and NF-κB activities. In response to high insulin, cardiac myoblasts increase the expression or the promyogenic transcription factors myocardin/SRF in a CHIP-dependent manner. Insulin potentiates TNF-α in inducing NF-κB and SRF/SRE activities. In hyperinsulinemic states, myocardin may act as a nuclear effector of insulin, promoting cardiac hypertrophy.

Transplantation of mesenchymal cells rejuvenated by the overexpression of telomerase and myocardin promotes revascularization and tissue repair in a murine model of hindlimb ischemia.

RATIONALE: The number and function of stem cells decline with aging, reducing the ability of stem cells to contribute to endogenous repair processes. The repair capacity of stem cells in older individuals may be improved by genetically reprogramming the stem cells to exhibit delayed senescence and enhanced regenerative properties. OBJECTIVE: We examined whether the overexpression of myocardin (MYOCD) and telomerase reverse transcriptase (TERT) enhanced the survival, growth, and myogenic differentiation of mesenchymal stromal cells (MSCs) isolated from adipose or bone marrow tissues of aged mice. We also examined the therapeutic efficacy of transplanted MSCs overexpressing MYOCD and TERT in a murine model of hindlimb ischemia. METHODS AND RESULTS: MSCs from adipose or bone marrow tissues of young (1 month old) and aged (12 months old) male C57BL/6 and apolipoprotein E-null mice were transiently transduced with lentiviral vectors encoding TERT, MYOCD, or both TERT and MYOCD. Flow cytometry and bromodeoxyuridine cell proliferation assays showed that transduction with TERT and, to a lesser extent, MYOCD, increased MSC viability and proliferation. In colony-forming assays, MSCs overexpressing TERT and MYOCD were more clonogenic than mock-transduced MSCs. Fas-induced apoptosis was inhibited in MSCs overexpressing MYOCD or TERT. When compared with aged mock-transduced MSCs, aged MSCs overexpressing TERT, MYOCD, or both TERT and MYOCD increased myogenic marker expression, blood flow, and arteriogenesis when transplanted into the ischemic hindlimbs of apolipoprotein E-null mice. CONCLUSIONS: The delivery of the TERT and MYOCD genes into MSCs may have therapeutic applications for restoring, or rejuvenating, aged MSCs from adipose and bone marrow tissues.