Design, Synthesis, and Biological Evaluation of New Peripheral 5HT2A Antagonists for Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is increasingly prevalent worldwide, causing serious liver complications, including nonalcoholic steatohepatitis. Recent findings suggest that peripheral serotonin (5-hydroxytryptamine, 5HT) regulates energy homeostasis, including hepatic lipid metabolism. More specifically, liver-specific 5HT2A knockout mice exhibit alleviated hepatic lipid accumulation and hepatic steatosis. Here, structural modifications of pimavanserin (CNS drug), a 5HT2A antagonist approved for Parkinson's disease, led us to synthesize new peripherally acting 5HT2A antagonists. Among the synthesized compounds, compound 14a showed good in vitro activity, good liver microsomal stability, 5HT subtype selectivity, and no significant inhibition of CYP and hERG. The in vitro and in vivo blood-brain barrier permeability study proved that 14a acts peripherally. Compound 14a decreased the liver weight and hepatic lipid accumulation in high-fat-diet-induced obesity mice. Our study suggests new therapeutic possibilities for peripheral 5HT2A antagonists in NAFLD.

Therapeutic effect of dichloroacetate against atherosclerosis via hepatic FGF21 induction mediated by acute AMPK activation.

Dyslipidemia-induced atherosclerosis, which has a risk of high morbidity and mortality, can be alleviated by metabolic activation associated with mitochondrial function. The effect of dichloroacetate (DCA), a general pyruvate dehydrogenase kinase (PDK) inhibitor, on in vivo energy expenditure in ApoE-/- mice fed a western diet (WD) has not yet been investigated. WD-fed ApoE-/- mice developed atherosclerotic plaques and hyperlipidemia along with obesity, which were significantly ameliorated by DCA administration. Increased oxygen consumption was associated with heat production in the DCA-treated group, with no change in food intake or physical activity compared with those of the control. These processes were correlated with the increased gene expression of Dio2 and Ucp-1, which represents brown adipose tissue (BAT) activation, in both WD-induced atherosclerosis and high-fat-induced obesity models. In addition, we found that DCA stimulated hepatic fibroblast growth factor 21 (Fgf21) mRNA expression, which might be important for lowering lipid levels and insulin sensitization via BAT activation, in a dose- and time-dependent manner associated with serum FGF21 levels. Interestingly, Fgf21 mRNA expression was mediated in an AMP-activated protein kinase (AMPK)-dependent manner within several minutes after DCA treatment independent of peroxisome proliferator-activated receptor alpha (PPARα). Taken together, the results suggest that enhanced glucose oxidation by DCA protects against atherosclerosis by inducing hepatic FGF21 expression and BAT activation, resulting in augmented energy expenditure for heat generation.

Identification of Novel Resorcinol Amide Derivatives as Potent and Specific Pyruvate Dehydrogenase Kinase (PDHK) Inhibitors.

Pyruvate dehydrogenase kinases (PDHKs) promote abnormal respiration in cancer cells. Studies with novel resorcinol amide derivatives based on VER-246608 (6) led to the identification of 19n and 19t containing five-membered heteroaromatic rings as unique structural features. These substances possess single-digit nanomolar activities against PDHKs. 19t exhibits higher potencies against PDHK1/2/4 than does 6 and inhibits only PDHKs among 366 kinases. Moreover, 19g, 19l, and 19s were found to be isotype-selective PDHK inhibitors. Molecular dynamics simulations provide a better understanding of how the heteroaromatic rings affect the activities of 19n and 19t on PDHK1/2/3/4. Moreover, 19n possesses a much higher antiproliferative activity against cancer cells than does 6. We demonstrated that the results of PDH assays better correlate with cellular activities than do those of PDHK kinase assays. Furthermore, 19n induces apoptosis of cancer cells via mitochondrial dysfunction, suppresses tumorigenesis, and displays a synergistic effect on satraplatin suppression of cancer cell proliferation.

Pyruvate Dehydrogenase Kinase Is a Metabolic Checkpoint for Polarization of Macrophages to the M1 Phenotype.

Metabolic reprogramming during macrophage polarization supports the effector functions of these cells in health and disease. Here, we demonstrate that pyruvate dehydrogenase kinase (PDK), which inhibits the pyruvate dehydrogenase-mediated conversion of cytosolic pyruvate to mitochondrial acetyl-CoA, functions as a metabolic checkpoint in M1 macrophages. Polarization was not prevented by PDK2 or PDK4 deletion but was fully prevented by the combined deletion of PDK2 and PDK4; this lack of polarization was correlated with improved mitochondrial respiration and rewiring of metabolic breaks that are characterized by increased glycolytic intermediates and reduced metabolites in the TCA cycle. Genetic deletion or pharmacological inhibition of PDK2/4 prevents polarization of macrophages to the M1 phenotype in response to inflammatory stimuli (lipopolysaccharide plus IFN-γ). Transplantation of PDK2/4-deficient bone marrow into irradiated wild-type mice to produce mice with PDK2/4-deficient myeloid cells prevented M1 polarization, reduced obesity-associated insulin resistance, and ameliorated adipose tissue inflammation. A novel, pharmacological PDK inhibitor, KPLH1130, improved high-fat diet-induced insulin resistance; this was correlated with a reduction in the levels of pro-inflammatory markers and improved mitochondrial function. These studies identify PDK2/4 as a metabolic checkpoint for M1 phenotype polarization of macrophages, which could potentially be exploited as a novel therapeutic target for obesity-associated metabolic disorders and other inflammatory conditions.

Discovery of Potent, Selective, and Orally Bioavailable Estrogen-Related Receptor-γ Inverse Agonists To Restore the Sodium Iodide Symporter Function in Anaplastic Thyroid Cancer.

An inverse agonist of estrogen-related receptor-γ (ERRγ), an orphan nuclear receptor encoded by E srrg, enhances sodium iodide symporter-mediated radioiodine uptake in anaplastic thyroid cancer (ATC) cells, thereby facilitating responsiveness to radioiodine therapy in vitro. We synthesized potent, selective, and orally bioavailable ERRγ-inverse agonists and evaluated their activity by analyzing in vitro pharmacology and absorption, distribution, metabolism, excretion, and toxicity profiles. X-ray crystallographic analysis of the ligand and ERRγ complex showed that 35 completely binds to the target protein (PDB 6A6K ). Our results showed improved radioiodine avidity in ATC cells through compound 35-mediated upregulation of iodide-handling genes, leading to enhanced responsiveness to radioiodine therapy in vitro. Importantly, in vivo 124I-positron emission tomography/computed tomography imaging revealed that 35 increases radioiodine avidity in CAL62 tumors. Collectively, these results demonstrated that 35 can be developed as a promising treatment for ERRγ-related cancer in the future.

Discovery of Novel Pyruvate Dehydrogenase Kinase 4 Inhibitors for Potential Oral Treatment of Metabolic Diseases.

Pyruvate dehydrogenase kinase 4 (PDK4) activation is associated with metabolic diseases including hyperglycemia, insulin resistance, allergies, and cancer. Structural modifications of hit anthraquinone led to the identification of a new series of allosteric PDK4 inhibitors. Among this series, compound 8c showed promising in vitro activity with an IC50 value of 84 nM. Good metabolic stability, pharmacokinetic profiles, and possible metabolites were suggested. Compound 8c improved glucose tolerance in diet-induced obese mice and ameliorated allergic reactions in a passive cutaneous anaphylaxis mouse model. Additionally, compound 8c exhibited anticancer activity by controlling cell proliferation, transformation, and apoptosis. From the molecular docking studies, compound 8c displayed optimal fitting in the lipoamide binding site (allosteric) with a full fitness, providing a new scaffold for drug development toward PDK4 inhibitors.

PDK4 Deficiency Suppresses Hepatic Glucagon Signaling by Decreasing cAMP Levels.

In fasting or diabetes, gluconeogenic genes are transcriptionally activated by glucagon stimulation of the cAMP-protein kinase A (PKA)-CREB signaling pathway. Previous work showed pyruvate dehydrogenase kinase (PDK) inhibition in skeletal muscle increases pyruvate oxidation, which limits the availability of gluconeogenic substrates in the liver. However, this study found upregulation of hepatic PDK4 promoted glucagon-mediated expression of gluconeogenic genes, whereas knockdown or inhibition of hepatic PDK4 caused the opposite effect on gluconeogenic gene expression and decreased hepatic glucose production. Mechanistically, PDK4 deficiency decreased ATP levels, thus increasing phosphorylated AMPK (p-AMPK), which increased p-AMPK-sensitive phosphorylation of cyclic nucleotide phosphodiesterase 4B (p-PDE4B). This reduced cAMP levels and consequently p-CREB. Metabolic flux analysis showed that the reduction in ATP was a consequence of a diminished rate of fatty acid oxidation (FAO). However, overexpression of PDK4 increased FAO and increased ATP levels, which decreased p-AMPK and p-PDE4B and allowed greater accumulation of cAMP and p-CREB. The latter were abrogated by the FAO inhibitor etomoxir, suggesting a critical role for PDK4 in FAO stimulation and the regulation of cAMP levels. This finding strengthens the possibility of PDK4 as a target against diabetes.

Insights of a Lead Optimization Study and Biological Evaluation of Novel 4-Hydroxytamoxifen Analogs as Estrogen-Related Receptor γ (ERRγ) Inverse Agonists.

We evaluated the in vitro pharmacology as well as the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of chemical entities that not only were shown to be highly selective agonists for ERRγ but also exhibited enhanced pharmacokinetic profile compared with 3 (GSK5182). 6g and 10b had comparable potency to 3 and were far more selective for ERRγ over the ERRα, -ß, and ERα. The in vivo pharmacokinetic profiles of 6g and 10b were further evaluated, as they possessed superior in vitro ADMET profiles compared to the other compounds. Additionally, we observed a significant increase of fully glycosylated NIS protein, key protein for radioiodine therapy in anaplastic thyroid cancer (ATC), in 6g- or 10b-treated CAL62 cells, which indicated that these compounds could be promising enhancers for restoring NIS protein function in ATC cells. Thus, 6g and 10b possess advantageous druglike properties and can be used to potentially treat various ERRγ-related disorders.

O-GlcNAcylation of Orphan Nuclear Receptor Estrogen-Related Receptor γ Promotes Hepatic Gluconeogenesis.

Estrogen-related receptor γ (ERRγ) is a major positive regulator of hepatic gluconeogenesis. Its transcriptional activity is suppressed by phosphorylation signaled by insulin in the fed state, but whether posttranslational modification alters its gluconeogenic activity in the fasted state is not known. Metabolically active hepatocytes direct a small amount of glucose into the hexosamine biosynthetic pathway, leading to protein O-GlcNAcylation. In this study, we demonstrate that ERRγ is O-GlcNAcylated by O-GlcNAc transferase in the fasted state. This stabilizes the protein by inhibiting proteasome-mediated protein degradation, increasing ERRγ recruitment to gluconeogenic gene promoters. Mass spectrometry identifies two serine residues (S317, S319) present in the ERRγ ligand-binding domain that are O-GlcNAcylated. Mutation of these residues destabilizes ERRγ protein and blocks the ability of ERRγ to induce gluconeogenesis in vivo. The impact of this pathway on gluconeogenesis in vivo was confirmed by the observation that decreasing the amount of O-GlcNAcylated ERRγ by overexpressing the deglycosylating enzyme O-GlcNAcase decreases ERRγ-dependent glucose production in fasted mice. We conclude that O-GlcNAcylation of ERRγ serves as a major signal to promote hepatic gluconeogenesis.

Synthesis and biological evaluation of novel 4-hydroxytamoxifen analogs as estrogen-related receptor gamma inverse agonists.

Estrogen-related receptor gamma (ERRγ) has recently been recognized as an attractive target for treating inflammation, cancer, and metabolic disorders. Herein, we discovered and demonstrated the in vitro pharmacology as well as the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of chemical entities that could act as highly selective inverse agonists for ERRγ. The results were comparable to those for GSK5182 (4), a leading ERRγ inverse agonist ligand. Briefly, the half-maximal inhibitory concentration (IC50) range of the synthesized compounds for ERRγ was 0.1-10 µM. Impressively, compound 24e exhibited potency comparable to 4 but was more selective for ERRγ over three other subtypes: ERRα, ERRß, and estrogen receptor α. Furthermore, compound 24e exhibited a superior in vitro ADMET profile compared to the other compounds. Thus, the newly synthesized class of ERRγ inverse agonists could be lead candidates for developing clinical therapies for ERRγ-related disorders.

Identification of Selective ERRγ Inverse Agonists.

GSK5182 (4) is currently one of the lead compounds for the development of estrogen-related receptor gamma (ERRγ) inverse agonists. Here, we report the design, synthesis, pharmacological and in vitro absorption, distribution, metabolism, excretion, toxicity (ADMET) properties of a series of compounds related to 4. Starting from 4, a series of analogs were structurally modified and their ERRγ inverse agonist activity was measured. A key pharmacophore feature of this novel class of ligands is the introduction of a heterocyclic group for A-ring substitution in the core scaffold. Among the tested compounds, several of them are potent ERRγ inverse agonists as determined by binding and functional assays. The most promising compound, 15g, had excellent binding selectivity over related subtypes (IC50 = 0.44, >10, >10, and 10 µM at the ERRγ, ERRα, ERRß, and ERα subtypes, respectively). Compound 15g also resulted in 95% transcriptional repression at a concentration of 10 µM, while still maintaining an acceptable in vitro ADMET profile. This novel class of ERRγ inverse agonists shows promise in the development of drugs targeting ERRγ-related diseases.

Propofol-ketamine or propofol-remifentanil for deep sedation and analgesia in pediatric patients undergoing burn dressing changes: a randomized clinical trial.

OBJECTIVE: In this study, we compared the propofol-ketamine and propofol-remifentanil combinations for deep sedation and analgesia during pediatric burn wound dressing changes. METHODS: Fifty pediatric patients aged 12-36 months, undergoing burn wound dressing changes, were randomly assigned to receive propofol-remifentanil (group PR) or propofol-ketamine (group PK) for deep sedation and analgesia. Patients in the group PR received 2 mg·kg(-1) propofol and 0.1 µg·kg(-1) remifentanil, and 0.05 µg·kg(-1) ·min(-1) remifentanil was infused continuously until the end of the procedure. Patients in the group PK received 2 mg·kg(-1) propofol and 1 mg·kg(-1) ketamine, and the same volume of isotonic saline was infused continuously until the end of the procedure. Additional propofol with remifentanil or ketamine was administered when required. Hemodynamic variables, drug requirements, occurrence of patient movement, surgeon's satisfaction score, recovery time, and the incidence of adverse events were recorded throughout the procedure and recovery. RESULTS: Recovery time was significantly shorter in the group PR compared to that in the group PK (10.3 [9.1-11.5] min vs 22.5 [20.3-25.6] min, median [interquartile range], respectively; P < 0.001). No significant hypotension or bradycardia occurred throughout the procedure. No significant differences were observed in terms of drug requirements, occurrence of patient movement, surgeon's satisfaction, incidence of respiratory depression, hypoxia, or nausea and vomiting CONCLUSIONS: The combinations of propofol-ketamine and propofol-remifentanil were effective for sedation and analgesia in pediatric patients undergoing burn dressing changes, but the propofol-remifentanil combination provided faster recovery compared to the propofol-ketamine combination.

Effect of ramosetron on the QT interval during sevoflurane anaesthesia in children: a prospective observational study.

BACKGROUND: We investigated the effects of concomitant administration of sevoflurane and ramosetron on the QT interval, the interval between the peak and end of the T wave (Tpe) and Tpe/QT ratio in children. OBJECTIVES: To compare the effects of concomitant administration of ramosetron and sevoflurane on heart rate corrected interval with Bazett's formula (QTc), Tpe interval and Tpe/QT ratio. DESIGN: A prospective observational study. SETTING: Elective orthopaedic surgery with patient-controlled analgesia. PATIENTS: Forty children aged between 3 and 12 years. INTERVENTION: ECG recordings were collected before induction (BASE), before sevoflurane administration (SEVO) and after the administration of ramosetron (SEVO and R). MAIN OUTCOME MEASURES: The heart rate corrected interval with Bazett's formula (QTc), Tpe interval and Tpe/QT ratio were calculated and the changes were analysed using repeated-measures analysis of variance (ANOVA). RESULTS: The QTc interval at BASE was 388.5 ±â€Š29.3 ms. It increased with sevoflurane anaesthesia to 414.9 ±â€Š21.4 ms and did not change with the administration of ramosetron (418.2 ±â€Š23.0 ms). The Tpe interval and Tpe/QT ratio did not differ between measurements. No ventricular arrhythmias occurred during the study. CONCLUSION: Ramosetron was not associated with prolongation of the QTc interval when it was given concomitantly with sevoflurane in children. No ventricular arrhythmias or other adverse effects occurred during the study.

PKB/Akt phosphorylation of ERRγ contributes to insulin-mediated inhibition of hepatic gluconeogenesis.

AIMS/HYPOTHESIS: Insulin resistance, a major contributor to the pathogenesis of type 2 diabetes, leads to increased hepatic glucose production (HGP) owing to an impaired ability of insulin to suppress hepatic gluconeogenesis. Nuclear receptor oestrogen-related receptor γ (ERRγ) is a major transcriptional regulator of hepatic gluconeogenesis. In this study, we investigated insulin-dependent post-translational modifications (PTMs) altering the transcriptional activity of ERRγ for the regulation of hepatic gluconeogenesis. METHODS: We examined insulin-dependent phosphorylation and subcellular localisation of ERRγ in cultured cells and in the liver of C57/BL6, leptin receptor-deficient (db/db), liver-specific insulin receptor knockout (LIRKO) and protein kinase B (PKB) ß-deficient (Pkbß (-/-)) mice. To demonstrate the role of ERRγ in the inhibitory action of insulin on hepatic gluconeogenesis, we carried out an insulin tolerance test in C57/BL6 mice expressing wild-type or phosphorylation-deficient mutant ERRγ. RESULTS: We demonstrated that insulin suppressed the transcriptional activity of ERRγ by promoting PKB/Akt-mediated phosphorylation of ERRγ at S179 and by eliciting translocation of ERRγ from the nucleus to the cytoplasm through interaction with 14-3-3, impairing its ability to promote hepatic gluconeogenesis. In addition, db/db, LIRKO and Pkbß (-/-) mice displayed enhanced ERRγ transcriptional activity due to a block in PKBß-mediated ERRγ phosphorylation during refeeding. Finally, the phosphorylation-deficient mutant ERRγ S179A was resistant to the inhibitory action of insulin on HGP. CONCLUSIONS/INTERPRETATION: These results suggest that ERRγ is a major contributor to insulin action in maintaining hepatic glucose homeostasis.

The utilisation of Complementary and Alternative Medicine (CAM) among ethnic minorities in South Korea.

BACKGROUND: Race has been reported to affect the use of complementary and alternative medicine (CAM), but there is very little research on the use of CAM by ethnicity in Korea. This study explores the prevalence of CAM use among ethnic minorities in South Korea. METHODS: The design is a descriptive and cross-sectional study. A convenience sample of ethnic minorities was recruited from two public healthcare centres in Gyeonggi province. The survey instrument included 37 questions regarding CAM use, factors influencing use of CAM, self-health management, and the socio-demographic profile of study participants. RESULTS: Sixty-two percent of study participants reported the use of CAM. Multivitamins (53.3%), acupuncture (48.9%), and traditional Korean herbal medicine (38.9%) were popular CAM modalities in our sample. Other notable CAM modalities included herbal plants, therapeutic massage, and moxibustion therapy. The majority of CAM users (52.2%) received CAM services to treat diseases or as a secondary treatment while receiving conventional care. Having positive perceptions toward the effectiveness of CAM was a major determining factor in CAM use. CONCLUSIONS: Physicians need to be aware of the fact that many ethnic minorities use CAM therapies. Many CAM users reported that they want doctors to know about their CAM use and have a basic understanding of traditional medicine in their home country. Overcoming language and cultural barriers will help reduce unwanted medical complications. High prevalence of CAM use among ethnic minorities in our study warrants further studies using larger sample population.

Regulation of acetylation of histone deacetylase 2 by p300/CBP-associated factor/histone deacetylase 5 in the development of cardiac hypertrophy.

RATIONALE: Histone deacetylases (HDACs) are closely involved in cardiac reprogramming. Although the functional roles of class I and class IIa HDACs are well established, the significance of interclass crosstalk in the development of cardiac hypertrophy remains unclear. OBJECTIVE: Recently, we suggested that casein kinase 2α1-dependent phosphorylation of HDAC2 leads to enzymatic activation, which in turn induces cardiac hypertrophy. Here we report an alternative post-translational activation mechanism of HDAC2 that involves acetylation of HDAC2 mediated by p300/CBP-associated factor/HDAC5. METHODS AND RESULTS: Hdac2 was acetylated in response to hypertrophic stresses in both cardiomyocytes and a mouse model. Acetylation was reduced by a histone acetyltransferase inhibitor but was increased by a nonspecific HDAC inhibitor. The enzymatic activity of Hdac2 was positively correlated with its acetylation status. p300/CBP-associated factor bound to Hdac2 and induced acetylation. The HDAC2 K75 residue was responsible for hypertrophic stress-induced acetylation. The acetylation-resistant Hdac2 K75R showed a significant decrease in phosphorylation on S394, which led to the loss of intrinsic activity. Hdac5, one of class IIa HDACs, directly deacetylated Hdac2. Acetylation of Hdac2 was increased in Hdac5-null mice. When an acetylation-mimicking mutant of Hdac2 was infected into cardiomyocytes, the antihypertrophic effect of either nuclear tethering of Hdac5 with leptomycin B or Hdac5 overexpression was reduced. CONCLUSIONS: Taken together, our results suggest a novel mechanism by which the balance of HDAC2 acetylation is regulated by p300/CBP-associated factor and HDAC5 in the development of cardiac hypertrophy.

Clusterin decreases hepatic SREBP-1c expression and lipid accumulation.

Hepatic steatosis is emerging as the most important cause of chronic liver disease and is associated with the increasing incidence of obesity with insulin resistance. Sterol regulatory binding protein-1c (SREBP-1c) is a master regulator of lipogenic gene expression in the liver. Hyperinsulinemia induces SREBP-1c transcription through liver X receptor (LXR), specificity protein 1, and SREBP-1c itself. Clusterin, an 80-kDa disulfide-linked heterodimeric protein, has been functionally implicated in several physiological processes including lipid transport; however, little is known about its effect on hepatic lipogenesis. The present study examined whether clusterin regulates SREBP-1c expression and lipid accumulation in the liver. Adenovirus-mediated overexpression of clusterin inhibited insulin- or LXR agonist-stimulated SREBP-1c expression in cultured liver cells. In reporter assays, clusterin inhibited SREBP-1c promoter activity. Moreover, adenovirus-mediated overexpression of clusterin in the livers of mice fed a high-fat diet inhibited hepatic steatosis through the inhibition of SREBP-1c expression. Reporter and gel shift assays showed that clusterin inhibits SREBP-1c expression via the repression of LXR and specificity protein 1 activity. This study shows that clusterin inhibits hepatic lipid accumulation through the inhibition of SREBP-1c expression and suggests that clusterin is a negative regulator of SREBP-1c expression and hepatic lipogenesis.

Protective role of clusterin/apolipoprotein J against neointimal hyperplasia via antiproliferative effect on vascular smooth muscle cells and cytoprotective effect on endothelial cells.

OBJECTIVE: Clusterin is induced in vascular smooth muscle cells (VSMCs) during atherosclerosis and injury-induced neointimal hyperplasia. However, its functional roles in VSMCs and endothelial cells remain controversial and elusive. This study was undertaken to clarify the role of clusterin in neointimal hyperplasia and elucidate its mechanism of action. METHODS AND RESULTS: Adenovirus-mediated overexpression of clusterin (Ad-Clu) repressed TNF-alpha-stimulated expression of MCP-1, fractalkine, ICAM-1, VCAM-1, and MMP-9, leading to inhibition of VSMC migration. Both Ad-Clu and secreted clusterin suppressed VSMC proliferation by inhibiting DNA synthesis, but not by inducing apoptosis. Ad-Clu upregulated p53 and p21(cip1/waf1) but downregulated cyclins D and E, leading to suppression of pRb phosphorylation and subsequent induction of G1 arrest in VSMCs. Clusterin deficiency augmented VSMC proliferation in vitro and accelerated neointimal hyperplasia in vivo, but concomitantly impaired reendothelialization in wire-injured murine femoral arteries. Moreover, Ad-Clu significantly reduced neointimal thickening in balloon-injured rat carotid arteries. Clusterin also diminished TNF-alpha-induced apoptosis of human umbilical vein endothelial cells and restored endothelial nitric oxide synthase expression suppressed by TNF-alpha. CONCLUSIONS: These results suggest that upregulation of clusterin during vascular injury may be a protective response against, rather than a causative response to, the development of neointimal hyperplasia.

Effects of PGC-1alpha on TNF-alpha-induced MCP-1 and VCAM-1 expression and NF-kappaB activation in human aortic smooth muscle and endothelial cells.

Increased oxidative stress in vascular cells is implicated in the pathogenesis of atherosclerosis. Reactive oxygen species (ROS) induce vascular inflammation via the proinflammatory cytokine/NF-kappaB pathway. Several lines of evidence suggest that peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1alpha) is an important regulator of intracellular ROS levels. However, no studies have examined the effects of PGC-1alpha on this process. We investigated the effects of PGC-1alpha on inflammatory molecule expression and activity of the redox-sensitive transcription factor, NF-kappaB, in vascular cells. PGC-1alpha expressed in human aortic smooth (HASMCs) and endothelial cells (HAECs) is upregulated by AMP-activated protein kinase activators, including metformin, rosiglitazone and alpha-lipoic acid. Tumor necrosis factor-alpha (TNF-alpha), a major proinflammatory factor in the development of vascular inflammation, stimulates intracellular ROS production through an increase in both mitochondrial ROS and NAD(P)H oxidase activity. Adenovirus-mediated overexpression of the PGC-1alpha gene in HASMCs and HAECs leads to a significant reduction in intracellular and mitochondrial ROS production as well as NAD(P)H oxidase activity. Consequently, NF-kappaB activity and MCP-1 and VCAM-1 induced by TNF-alpha are suppressed. Our data support the possibility that agents stimulating PGC-1alpha expression in the vasculature aid in preventing the development of atherosclerosis.