scholarly journals Peroxisome Proliferator-Activated ReceptorγRegulates the Expression of Lipid Phosphate Phosphohydrolase 1 in Human Vascular Endothelial Cells

PPAR Research ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yazi Huang ◽  
Beilei Zhao ◽  
Yahan Liu ◽  
Nanping Wang

Lipid phosphate phosphohydrolase 1 (LPP1), a membrane ectophosphohydrolase regulating the availability of bioactive lipid phosphates, plays important roles in cellular signaling and physiological processes such as angiogenesis and endothelial migration. However, the regulated expression of LPP1 remains largely unknown. Here, we aimed to examine a role of peroxisome proliferator-activated receptorγ(PPARγ) in the transcriptional control ofLPP1gene expression. In human umbilical vein endothelial cells (HUVECs), quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) demonstrated that activation of PPARγincreased the mRNA level of LPP1. Chromatin immunoprecipitation assay showed that PPARγbinds to the putative PPAR-responsive elements (PPREs) within the 5′-flanking region of the humanLPP1gene. Genomic fragment containing 1.7-kilobase of the promoter region was cloned by using PCR. The luciferase reporter assays demonstrated that overexpression of PPARγand rosiglitazone, a specific ligand for PPARγ, could significantly upregulate the reporter activity. However, site-directed mutagenesis of the PPRE motif abolished the induction. In conclusion, our results demonstrated that PPARγtranscriptionally activated the expression ofLPP1gene in ECs, suggesting a potential role of PPARγin the metabolism of phospholipids.

2003 ◽  
Vol 285 (6) ◽  
pp. H2298-H2308 ◽  
Author(s):  
Erin K. Ceaser ◽  
Anup Ramachandran ◽  
Anna-Liisa Levonen ◽  
Victor M. Darley-Usmar

Oxidized lipids are capable of initiating diverse cellular responses through both receptor-mediated mechanisms and direct posttranslational modification of proteins. Typically, exposure of cells to low concentrations of oxidized lipids induces cytoprotective pathways, whereas high concentrations result in apoptosis. Interestingly, mitochondria can contribute to processes that result in either cytoprotection or cell death. The role of antioxidant defenses such as glutathione in adaptation to stress has been established, but the potential interaction with mitochondrial function is unknown and is examined in this article. Human umbilical vein endothelial cells (HUVEC) were exposed to oxidized LDL (oxLDL) or the electrophilic cyclopentenone 15-deoxy-Δ12,14-PGJ2 (15d-PGJ2). We demonstrate that complex I activity, but not citrate synthase or cytochrome- c oxidase, is significantly induced by oxLDL and 15d-PGJ2. The mechanism is not clear at present but is independent of the induction of GSH, peroxisome proliferator-activated receptor (PPAR)-γ, and PPAR-α. This response is dependent on the induction of oxidative stress in the cells because it can be prevented by nitric oxide, probucol, and the SOD mimetic manganese(III) tetrakis(4-benzoic acid) porphyrin chloride. This increased complex I activity appears to contribute to protection against apoptosis induced by 4-hydroxynonenal.


PPAR Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Lei Xu ◽  
Gang Zhao ◽  
Hong Zhu ◽  
Shijun Wang ◽  
Aijun Sun ◽  
...  

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is one of the major receptors expressed on the endothelium of arterial wall with a key role in endothelial dysfunction and the development of atherosclerosis. Recent evidence suggested that LOX-1 is upregulated under the condition of insulin resistance and could be suppressed by the antidiabetic drugs. We previously also confirmed that Thiazolidinedione (TZD) has the inhibitory effect on LOX-1 in ox-LDL-induced endothelial cells. However, the underlying mechanism is unclear. Here we showed that Rosiglitazone treatment significantly attenuated the expressions of LOX-1, ICAM-1, VCAM-1, p47phox, and the atherosclerotic lesions in ApoE-/- mice with high-fat diet. In vitro, we revealed that Rosiglitazone inhibited LOX-1 by regulating miR-590-5p. Ox-LDL-mediated ICAM-1, VCAM-1, and p47phox were significantly reduced by Rosiglitazone, but all reversed after pretreating the cells with antagomiR-590-5p. Induction with Rosiglitazone activated PPAR-γ and promoted its nuclear translocation in cultured human umbilical vein endothelial cells (HUVECs). The nuclear PPAR-γ upregulated the miR-590-5p level through binding to its transcriptional promoter region. Retaining PPAR-γ in cytoplasm by transfecting with PPAR-γ⊿NLS plasmid in HUVECs failed to activate miR-590-5p. Mutation of the promoter region of PPAR-γ also reduced the miR-590-5p promoter luciferase activity. Collectively, these data indicated that PPAR-γ may have the therapeutic potential in atherosclerosis via the transcriptional regulation of miR-590-5p in endothelial cells.


Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5247-5254 ◽  
Author(s):  
Victor Aguilar ◽  
Jean-Sébastien Annicotte ◽  
Xavier Escote ◽  
Joan Vendrell ◽  
Dominique Langin ◽  
...  

Cell cycle regulators such as cyclins, cyclin-dependent kinases, or retinoblastoma protein play important roles in the differentiation of adipocytes. In the present paper, we investigated the role of cyclin G2 as a positive regulator of adipogenesis. Cyclin G2 is an unconventional cyclin which expression is up-regulated during growth inhibition or apoptosis. Using the 3T3-F442A cell line, we observed an up-regulation of cyclin G2 expression at protein and mRNA levels throughout the process of cell differentiation, with a further induction of adipogenesis when the protein is transiently overexpressed. We show here that the positive regulatory effects of cyclin G2 in adipocyte differentiation are mediated by direct binding of cyclin G2 to peroxisome proliferator-activated receptor γ (PPARγ), the key regulator of adipocyte differentiation. The role of cyclin G2 as a novel PPARγ coactivator was further demonstrated by chromatin immunoprecipitation assays, which showed that the protein is present in the PPARγ-responsive element of the promoter of aP2, which is a PPARγ target gene. Luciferase reporter gene assays, showed that cyclin G2 positively regulates the transcriptional activity of PPARγ. The role of cyclin G2 in adipogenesis is further underscored by its increased expression in mice fed a high-fat diet. Taken together, our results demonstrate a novel role for cyclin G2 in the regulation of adipogenesis.


2005 ◽  
Vol 73 (2) ◽  
pp. 1209-1213 ◽  
Author(s):  
Lena Serghides ◽  
Kevin C. Kain

ABSTRACT Peroxisome proliferator-activated receptor γ-retinoid X receptor (PPARγ-RXR) agonists had minimal effects on the surface levels of CD36, intercellular cell adhesion molecule-1, or platelet-endothelial cell adhesion molecule-1 and had no effect on the cytoadherence of infected erythrocytes to either human umbilical vein endothelial cells or human microvascular endothelial cells or on malaria-induced interleukin-6 secretion from these cells. PPARγ-RXR agonists do not significantly modify malaria-infected erythrocyte-endothelial cell interactions in vitro.


Pteridines ◽  
2000 ◽  
Vol 11 (4) ◽  
pp. 137-141
Author(s):  
Masakazu Ishii ◽  
Shunichi Shimizu ◽  
Kazuhiro Shiota ◽  
Yuji Kiuchi ◽  
Toshinori Yamamoto

Abstract We investigated the effects of troglitazone, which is a ligand of nuclear transcription factor peroxisome proliferator- activated receptor-γ (PPAR-γ), on insulin-induced tetrahydrobiopterin (BH4) synthesis in mouse brain microvascular endothelial cells (MBMECs). BH4 content was determined as biopterin, by reversed-phase high performance liquid chromatography using fluorometric detection. Measurement of mRNA level of GTP cyclohydrolase I (GTPCH), which is a rate-limiting enzyme for de novo BH4 synthesis, was performed by reverse transcription- polymerase chain reaction (RT -PCR). Addition of insulin (10µg/ml) to endothelial cells increased intracellular BH4 content and GTPCH mRNA level, and the insulin-induced increase in BH4 content and GTPCH mRNA level was further stimulated by co-treatment with troglitazone (0.3-3 µM). However, the expression of PPAR-γ mRNA in untreated and insulin-treated endothelial cells was not detected. Moreover, bezafibrate (1-10 µM), a ligand of PPAR-δ, did not affect BH4 synthesis in insulin-treated endothehal cells. These findings suggest that troglitazone stimulates insulin-induced BH4 synthesis in endothelial cells with the induction of GTPCH through PPAR-γ- and PPAR-δ-independent mechanism


2020 ◽  
Vol 21 (5) ◽  
pp. 1575 ◽  
Author(s):  
Wuyang Huang ◽  
Ruth Paulina Hutabarat ◽  
Zhi Chai ◽  
Tiesong Zheng ◽  
Weimin Zhang ◽  
...  

Blueberries are rich in antioxidant anthocyanins. The hypotensive effects of blueberry anthocyanins in endothelial cells was investigated here. Pretreatment with blueberry anthocyanin extract, malvidin, malvidin-3-glucoside, and malvidin-3-galactoside significantly ameliorated high-glucose-induced damage by enhancing endogenous antioxidant superoxide dismutase (SOD) and heme oxygenase-1 (HO-1), lowering reactive oxygen species (ROS) generation and NADPH oxidase isoform 4 (NOX4) expression, and increasing the cell vitalities. They also effectively induced a vasodilatory effect by increasing the vasodilator nitric oxide (NO) and its promoters endothelial NO synthase (eNOS) and peroxisome proliferator-activated receptor-γ (PPARγ) levels as well as by decreasing the vasoconstrictor angiotensin-converting enzyme (ACE), xanthine oxidase-1 (XO-1), and low-density lipoprotein (LDL) levels. The activation of phosphoinositide 3-kinase (PI3K)/Akt signaling pathway and the breakdown of protein kinase C zeta (PKCζ) pathway were involved in the bioactivities. The results indicated blueberry anthocyanins protected endothelial function against high-glucose (HG) injury via antioxidant and vasodilatory mechanisms, which could be promising molecules as a hypotensive nutraceutical for diabetes patients.


PPAR Research ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Jinbo Liu ◽  
Changlin Lu ◽  
Fuwang Li ◽  
Haining Wang ◽  
Liyun He ◽  
...  

Tetrahydrobiopterin (BH4) is an essential cofactor for endothelial nitric oxide (NO) synthase. Guanosine 5′-triphosphate cyclohydrolase-I (GTPCH-I) is a key limiting enzyme for BH4 synthesis. In the present in vitro study, we investigated whether peroxisome proliferator-activated receptorα(PPAR-α) agonist fenofibrate could recouple eNOS by reversing low-expression of intracellular BH4 in endothelial cells and discussed the potential mechanisms. After human umbilical vein endothelial cells (HUVECs) were treated with lipopolysaccharide (LPS) for 24 hours, the levels of cellular eNOS, BH4 and cell supernatant NO were significantly reduced compared to control group. And the fluorescence intensity of intracellular ROS was significantly increased. But pretreated with fenofibrate (10 umol/L) for 2 hours before cells were induced by LPS, the levels of eNOS, NO, and BH4 were significantly raised compared to LPS treatment alone. ROS production was markedly reduced in fenofibrate group than LPS group. In addition, our results showed that the level of intracellular GTPCH-I detected by western blot was increased in a concentration-dependent manner after being treated with fenofibrate. These results suggested that fenofibrate might help protect endothelial function and against atherosclerosis by increasing level of BH4 and decreasing production of ROS through upregulating the level of intracellular GTPCH-I.


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