BACKGROUND: Oleic acid (OA) stimulates vascular smooth muscle cell (VSMC) proliferation and migration. The precise mechanism is still unclear. We sought to investigate the effects of peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator-1 alpha (PGC-1alpha) on OA-induced VSMC proliferation and migration. PRINCIPAL FINDINGS: Oleate and palmitate, the most abundant monounsaturated fatty acid and saturated fatty acid in plasma, respectively, differently affect the mRNA and protein levels of PGC-1alpha in VSMCs. OA treatment resulted in a reduction of PGC-1alpha expression, which may be responsible for the increase in VSMC proliferation and migration caused by this fatty acid. In fact, overexpression of PGC-1alpha prevented OA-induced VSMC proliferation and migration while suppression of PGC-1alpha by siRNA enhanced the effects of OA. In contrast, palmitic acid (PA) treatment led to opposite effects. This saturated fatty acid induced PGC-1alpha expression and prevented OA-induced VSMC proliferation and migration. Mechanistic study demonstrated that the effects of PGC-1alpha on VSMC proliferation and migration result from its capacity to prevent ERK phosphorylation. CONCLUSIONS: OA and PA regulate PGC-1alpha expression in VSMCs differentially. OA stimulates VSMC proliferation and migration via suppression of PGC-1alpha expression while PA reverses the effects of OA by inducing PGC-1alpha expression. Upregulation of PGC-1alpha in VSMCs provides a potential novel strategy in preventing atherosclerosis.

Many aspects of energy metabolism, including glucose and lipid homeostasis and mitochondrial oxidative metabolism, are under precise control by the mammalian circadian clock. However, the molecular mechanism for coordinate integration of the circadian clock and various metabolic pathways is poorly understood. Here we show that BAF60a, a chromatin-remodeling complex subunit, is rhythmically expressed in the liver of mice. Mice with liver-specific knockdown of BAF60a show abnormalities in the rhythmic expression pattern of clock and metabolic genes and in the circulating metabolite profile. Consistently, Knockdown of BAF60a impairs the oscillation of clock genes in serum-shocked HepG2 cells. At the molecular level, BAF60a activates Bmal1 and G6Pase transcription via the coactivation of RORα. In addition, BAF60a is present near RORE on the proximal Bmal1 and G6Pase promoters and turns the chromatin structure into active state. Conclusion: Our data suggest a critical role for BAF60a in the coordinate regulation of hepatic circadian clock and energy metabolism in mammals.

PGC-1alpha mRNA and protein are elevated in islets from multiple animal models of diabetes. Overexpression of PGC-1alpha impairs glucose-stimulated insulin secretion (GSIS). However, it is not well known which metabolic events lead to upregulation of PGC-1alpha in the beta-cells under pathophysiological condition. In present study, we have investigated effects of chronic hyperlipidemia and hyperglycemia on PGC-1alpha mRNA expression in isolated rat islets. Isolated rat islets are chronically incubated with 0, 0.2 and 0.4 mM oleic acid/palmitic acid (free fatty acids, FFA) or 5.5 and 25 mM glucose for 72 h. FFA dose-dependently increases PGC-1alpha mRNA expression level in isolated islets. FFA also increases PGC-1alpha expression in mouse beta-cell-derived beta TC3 cell line. In contrast, 25 mM glucose decreases expression level of PGC-1alpha. Inhibition of PGC-1alpha by siRNA improves FFA-induced impairment of GSIS in islets. These data suggest that hyperlipidemia and hyperglycemia regulate PGC-1alpha expression in islets differently, and elevated PGC-1alpha by FFA plays an important role in chronic hyperlipidemia-induced beta-cell dysfunction.

Peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator-1 alpha (PGC-1alpha) coactivates multiple transcription factors and regulates several metabolic processes. The current study investigated the role of PGC-1alpha in the induction of apoptosis in human epithelial ovarian cancer cells. The PGC-1alpha mRNA level between human ovaries and human ovarian epithelial tumors was examined by quantitative RT-PCR. Less PGC-1alpha expression was found in the surface epithelium of malignant tumors compared with normal ovaries. Overexpression of PGC-1alpha in human epithelial ovarian cancer cell line Ho-8910 induced cell apoptosis through the coordinated regulation of Bcl-2 and Bax expression. Microarray analyses confirmed that PGC-1alpha dramatically affected the apoptosis-related genes in Ho-8910 cells. Mitochondrial functional assay showed that the induction of apoptosis was through the terminal stage by the release of cytochrome c. Furthermore, PGC-1alpha-induced apoptosis was partially, but not completely, blocked by PPARgamma antagonist (GW9662), and suppression of PPARgamma expression by siRNA also inhibited PGC-1alpha-induced apoptosis in Ho-8910 cells. These data suggested that PGC-1alpha exerted its effect through a PPARgamma-dependent pathway. Our findings indicated that PGC-1alpha was involved in the apoptotic signal transduction pathways and downregulation of PGC-1alpha may be a key point in promoting epithelial ovarian cancer growth and progression.

Vessel endothelium injury caused by reactive oxygen species (ROS) including H2O2 plays a critical role in the pathogenesis of cardiovascular disorders. Therefore, drug targeting ROS elimination has highly clinical values in cardiovascular therapy. The plant of Radix Ophiopogon japonicus is a traditional Chinese herbal medicine that has been commonly used for prevention and treatment of cardiovascular diseases for a long history. However, the effective component mediating its beneficial effects remains unknown. In the present study, we investigated the action of Ophiopogonin D (OP-D), one of the most bioactive components of Radix Ophiopogon japonicus, in an endothelial injury model induced by H2O2. We found that OP-D inhibited mRNA levels of antioxidant, inflammatory and apoptotic genes in a dose-dependent manner. H2O2-induced lipid peroxidation and protein carbonylation were reduced by OP-D pretreatment. Mitochondrial ROS generation and cell apoptosis were also attenuated in OP-D pretreated cells. In addition, OP-D restored cellular total antioxidative capacity and inhibited the release of inflammatory cytokines. Furthermore, OP-D suppressed the enzymatic activity of Catalase, HO-1, and Caspases. Finally, OP-D blocked activation of NF-κB and ERK signaling cascades. Taken together, our findings provide the first evidence that OP-D plays a protective role as an effective antioxidant in H2O2-induced endothelial injury. Ophiopogonin D can be therefore developed as a novel drug for the therapy of cardiovascular disorders.

BACKGROUND The aim of this study was to investigate the potential beneficial effects of celastrol, a compound with anti-inflammatory and antioxidant properties, on vascular smooth muscle cells (VSMCs) under hypertensive conditions. METHODS Hypertension was induced in rats by fructose feeding. Hypertensive rats were injected with celastrol, and systolic and diastolic blood pressure were monitored by the tail-cuff method. Insulin sensitivity in animals was measured by GTT. Serum levels of inflammatory cytokines were determined by ELISA. Real-time RT-PCR and Western blot were applied to quantify mRNA and protein levels in tissues and primary cultured VSMCs. Generation of reactive oxygen species (ROS) was measured using lucigenin chemiluminescence for tissue homogenates and DCF-DA staining for VSMC cells. RESULTS Celastrol decreased both systolic and diastolic blood pressure while improving insulin sensitivity in fructose-induced hypertensive rats. Celastrol also inhibited vascular and cardiac hypertrophy. Hypertension augmented circulating and mRNA levels of inflammatory cytokines, and celastrol treatment suppressed their induction. Celastrol also blocked activation of ERK/MAPK and Akt signaling both in vivo and in vitro. More importantly, celastrol increased heme oxygenase-1 (HO-1) expression and activity, whereas zinc protoporphyrin 9 (ZnPP9), a HO-1 inhibitor, partially abolished the beneficial effects of celastrol on hypertensive rats and VSMCs. Finally, ROS generation in tissue homogenates and in VSMCs was reduced by celastrol. CONCLUSIONS These findings suggest that celastrol attenuates hypertension-induced inflammation and oxidative stress in VSMCs via HO-1 induction, and this compound may therefore serve as a novel drug to treat hypertension.

Context: Ligustrazine (Lig) is a compound isolated from the rhizome of Ligusticum chuanxiong Hort. (Umbelliferae) and has been reported to be effective for the treatment of a variety of vascular diseases. Objective: The anti-atherosclerotic activities of Lig are evaluated in vivo for the first time in the present study. Materials and methods: We gave rats a single injection of vitamin D3 and then fed them with an atherogenic diet for 6 weeks to induce atherosclerosis. Lig was simultaneously given to rats by gavage at the dose of 20 or 80 mg/kg in the therapy groups. Multiple approaches including spectrophometry, hematoxylin and eosin staining and quantitative RT-PCR were applied to investigate the effects of Lig on blood parameters, aorta and liver histology, and gene expression. In addition, the solely effects of Lig on food intake, body weight gain, and taste preference were also evaluated. Results: We found that two doses of Lig treatment decreased the total cholesterol levels by 65.2% and 76.7%, respectively, in the plasma. Triglyceride (by 53.2% and 77.9%) and low density lipoprotein (by 71.2% and 79.0%) levels were also decreased. However, high density lipoprotein level was slightly increased. The circulating endothelial cells were decreased by 42.2% and 60.0% in Lig-treated rats, indicating the attenuation of endothelial injury. In contrast, Lig restored the total antioxidant capacity and SOD1 activity while decreasing the MDA generation. Furthermore, Lig improved liver dysfunction by decreasing ALT (by 13.0% and 49.7%) and AST (by 10.7% and 14.3%) levels. Histological examinations revealed that Lig suppressed atherosclerotic plaque progression in the thoracic aorta and lipid accumulation in the liver. At the transcriptional level, Lig inhibited the induction of antioxidant genes both in aorta and in liver. Lig also suppressed the mRNA expression of the genes involved in the hepatic fatty acid oxidation. Finally, Lig had a minimum effect on food intake, body weight gain, and taste preference. Discussion and conclusion: Our results suggest that Lig suppresses the development of atherosclerosis and hepatic lipid accumulation via the alleviation of oxidative stress and the improvement of dyslipidemia.