Peroxisome Proliferator-Activated Receptor γ Plays a Critical Role in Inhibition of Cardiac Hypertrophy In Vitro and In Vivo

The PPAR (peroxisome-proliferator-activated receptor) family consists of three ligand-activated nuclear receptors: PPARα, PPARβ/δ and PPARγ. These PPARs have important roles in the regulation of glucose and fatty acid metabolism, cell differentiation and immune function, but were also found to be expressed in endothelial cells in the late 1990s. The early endothelial focus of PPARs was PPARγ, the molecular target for the insulin-sensitizing thiazolidinedione/glitazone class of drugs. Activation of PPARγ was shown to inhibit angiogenesis in vitro and in models of retinopathy and cancer, whereas more recent data point to a critical role in the development of the vasculature in the placenta. Similarly, PPARα, the molecular target for the fibrate class of drugs, also has anti-angiogenic properties in experimental models. In contrast, unlike PPARα or PPARγ, activation of PPARβ/δ induces angiogenesis, in vitro and in vivo, and has been suggested to be a critical component of the angiogenic switch in pancreatic cancer. Moreover, PPARβ/δ is an exercise mimetic and appears to contribute to the angiogenic remodelling of cardiac and skeletal muscle induced by exercise. This evidence and the emerging mechanisms by which PPARs act in endothelial cells are discussed in more detail.

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PPARβ/δ Agonist GW501516 Inhibits Tumorigenesis and Promotes Apoptosis of the Undifferentiated Nasopharyngeal Carcinoma C666-1 Cells by Regulating miR-206

Oncology Research Featuring Preclinical and Clinical Cancer Therapeutics ◽

10.3727/096504019x15518706875814 ◽

2019 ◽

Vol 27 (8) ◽

pp. 923-933 ◽

Cited By ~ 1

Author(s):

Linglan Gu ◽

Yi Shi ◽

Weimin Xu ◽

Yangyang Ji

Keyword(s):

Nasopharyngeal Carcinoma ◽

Critical Role ◽

Current Data ◽

Peroxisome Proliferator ◽

Dependent Manner ◽

Promoting Effect ◽

Apoptotic Pathway ◽

Peroxisome Proliferator Activated Receptor

In previous investigations, we reported that peroxisome proliferator-activated receptor β/δ (PPARβ/δ) activation by GW501516 inhibits proliferation and promotes apoptosis in the undifferentiated C666-1 nasopharyngeal carcinoma (NPC) cells by modulating caspase-dependent apoptotic pathway. In the present study, the mechanism by which GW501516 induces apoptosis was explored from the perspective of microRNA (miRNA) expression. Among the assayed miRNAs that were involved in regulating the expression of antiapoptotic protein Bcl-2, miR-206 was increased significantly and specifically by GW501516 in C666-1 cells at both the in vitro level and at the in vivo xenograft samples. The induction on miR-206 expression caused by GW501516 was capable of being antagonized by the PPARβ/δ antagonist GSK3787 and AMPK antagonist dorsomorphin in C666-1 cells. GW501516’s suppression on the growth and apoptosis of C666-1 cells was found to be dependent on the presence of miR-206. miR-206 overexpression resulted in suppressed proliferation and colony formation ability, and further triggered increased apoptosis in C666-1 cells in a caspase-dependent manner. The expression of cleaved caspase 3 and caspase 9, and the ratio of Bax to Bcl-2 were elevated remarkably by miR-206. Consistent with the in vitro result, miR-206 was corroborated to suppress the ectopic NPC xenograft tumorigenesis that derived from the C666-1 cells in BALB/c nu/nu mice. Taken together, the current data demonstrated that miR-206 plays a critical role in the direct apoptosis-promoting effect induced by GW501516 in C666-1 cells. Furthermore, the emphasized tumor-suppressive role of miR-206 in the C666-1 cells indicates that it has the potential to provide a new therapeutic approach for the undifferentiated NPC.

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SREBP-1c/MicroRNA 33b Genomic Loci Control Adipocyte Differentiation

Molecular and Cellular Biology ◽

10.1128/mcb.00745-15 ◽

2016 ◽

Vol 36 (7) ◽

pp. 1180-1193 ◽

Cited By ~ 28

Author(s):

Nathan L. Price ◽

Brandon Holtrup ◽

Stephanie L. Kwei ◽

Martin Wabitsch ◽

Matthew Rodeheffer ◽

...

Keyword(s):

Lipid Droplet ◽

Target Genes ◽

Adipocyte Differentiation ◽

Regulatory Element ◽

Critical Role ◽

Peroxisome Proliferator ◽

Peroxisome Proliferator Activated Receptor ◽

The Impact

White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1, respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promotingin vitroadipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precludingin vivoassessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human preadipocytes, along withSREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired preadipocyte proliferation and reduced lipid droplet formation and the induction of peroxisome proliferator-activated receptor γ (PPARγ) target genes during differentiation. These effects may be mediated by targeting of HMGA2, cyclin-dependent kinase 6 (CDK6), and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease.

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Peroxisome proliferator-activated receptor-γ activators inhibit endothelin-1-related cardiac hypertrophy in rats

Clinical Science ◽

10.1042/cs103s016s ◽

2002 ◽

Vol 103 (s2002) ◽

pp. 16S-20S ◽

Cited By ~ 47

Author(s):

Satoshi SAKAI ◽

Takashi MIYAUCHI ◽

Yoko IRUKAYAMA-TOMOBE ◽

Takehiro OGATA ◽

Katsutoshi GOTO ◽

...

Keyword(s):

Cardiac Hypertrophy ◽

Left Ventricular ◽

Sham Operation ◽

Peroxisome Proliferator ◽

Peroxisome Proliferator Activated Receptor ◽

Endothelin 1 ◽

Vehicle Treatment ◽

Pioglitazone Treatment

Endothelin-1 (ET-1) causes cardiac hypertrophy, and ET receptor antagonists inhibit the development of cardiac hypertrophy in vitro and in vivo. Peroxisome proliferator-activated receptor γ (PPARγ), a member of the family of nuclear receptors, suppresses activator protein-1 (AP-1). We investigated the effects of the thiazolidinediones troglitazone and pioglitazone, activators of PPARγ, on cardiac hypertrophy due to pressure overload provoked by abdominal aortic banding (AB) in rats. Rats were divided into four groups: sham operation with vehicle treatment (n = 5); AB surgery with vehicle treatment (n = 6); AB surgery with troglitazone treatment (100mg·kg-1·day-1; n = 5); and AB surgery with pioglitazone treatment (10mg·kg-1·day-1; n = 8). Treatments were started 7 days before AB surgery, and left ventricular (LV) hypertrophy was assessed 24h after surgery. The ratio of LV weight/body weight (BW) was significantly increased in AB rats compared with sham-operated rats; treatment of AB rats with troglitazone or pioglitazone significantly inhibited the increase in LV weight/BW. Expression of ET-1 mRNA was markedly enhanced in the left ventricles of AB rats; treatment with troglitazone or pioglitazone lowered expression significantly. Suppression of cardiac hypertrophy by pioglitazone treatment was accompanied by a decrease in expression of the gene encoding brain natriuretic factor, a molecular marker for cardiac hypertrophy, in AB rats. Because the ET-1 gene has AP-1 response elements in its 5´-flanking region, the thiazolidinediones troglitazone and pioglitazone may inhibit cardiac hypertrophy partly through suppression of AP-1-induced ET-1 gene up-regulation.

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Adipocyte PHLPP2 inhibition prevents obesity-induced fatty liver

Nature Communications ◽

10.1038/s41467-021-22106-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

KyeongJin Kim ◽

Jin Ku Kang ◽

Young Hoon Jung ◽

Sang Bae Lee ◽

Raffaela Rametta ◽

...

Keyword(s):

Fatty Liver ◽

Whole Body ◽

Acid Oxidation ◽

Chow Diet ◽

Peroxisome Proliferator ◽

Obese Mice ◽

Ph Domain ◽

Peroxisome Proliferator Activated Receptor

AbstractIncreased adiposity confers risk for systemic insulin resistance and type 2 diabetes (T2D), but mechanisms underlying this pathogenic inter-organ crosstalk are incompletely understood. We find PHLPP2 (PH domain and leucine rich repeat protein phosphatase 2), recently identified as the Akt Ser473 phosphatase, to be increased in adipocytes from obese mice. To identify the functional consequence of increased adipocyte PHLPP2 in obese mice, we generated adipocyte-specific PHLPP2 knockout (A-PHLPP2) mice. A-PHLPP2 mice show normal adiposity and glucose metabolism when fed a normal chow diet, but reduced adiposity and improved whole-body glucose tolerance as compared to Cre- controls with high-fat diet (HFD) feeding. Notably, HFD-fed A-PHLPP2 mice show increased HSL phosphorylation, leading to increased lipolysis in vitro and in vivo. Mobilized adipocyte fatty acids are oxidized, leading to increased peroxisome proliferator-activated receptor alpha (PPARα)-dependent adiponectin secretion, which in turn increases hepatic fatty acid oxidation to ameliorate obesity-induced fatty liver. Consistently, adipose PHLPP2 expression is negatively correlated with serum adiponectin levels in obese humans. Overall, these data implicate an adipocyte PHLPP2-HSL-PPARα signaling axis to regulate systemic glucose and lipid homeostasis, and suggest that excess adipocyte PHLPP2 explains decreased adiponectin secretion and downstream metabolic consequence in obesity.

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The lipid-lowering drug fenofibrate combined with si-HOTAIR can effectively inhibit the proliferation of gliomas

BMC Cancer ◽

10.1186/s12885-021-08417-z ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Wei Zhu ◽

Hongyang Zhao ◽

Fenfen Xu ◽

Bin Huang ◽

Xiaojing Dai ◽

...

Keyword(s):

Noncoding Rna ◽

Glioma Cells ◽

Lipid Lowering ◽

Fibric Acid Derivative ◽

Peroxisome Proliferator ◽

Glioma Invasion ◽

Peroxisome Proliferator Activated Receptor ◽

Lncrna Hotair

Abstract Background Fenofibrate is a fibric acid derivative known to have a lipid-lowering effect. Although fenofibrate-induced peroxisome proliferator-activated receptor alpha (PPARα) transcription activation has been shown to play an important role in the malignant progression of gliomas, the underlying mechanisms are poorly understood. Methods In this study, we analyzed TCGA database and found that there was a significant negative correlation between the long noncoding RNA (lncRNA) HOTAIR and PPARα. Then, we explored the molecular mechanism by which lncRNA HOTAIR regulates PPARα in cell lines in vitro and in a nude mouse glioma model in vivo and explored the effect of the combined application of HOTAIR knockdown and fenofibrate treatment on glioma invasion. Results For the first time, it was shown that after knockdown of the expression of HOTAIR in gliomas, the expression of PPARα was significantly upregulated, and the invasion and proliferation ability of gliomas were obviously inhibited. Then, glioma cells were treated with both the PPARα agonist fenofibrate and si-HOTAIR, and the results showed that the proliferation and invasion of glioma cells were significantly inhibited. Conclusions Our results suggest that HOTAIR can negatively regulate the expression of PPARα and that the combination of fenofibrate and si-HOTAIR treatment can significantly inhibit the progression of gliomas. This introduces new ideas for the treatment of gliomas.

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The Novel Role of PGC1α in Bone Metabolism

International Journal of Molecular Sciences ◽

10.3390/ijms22094670 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4670

Author(s):

Cinzia Buccoliero ◽

Manuela Dicarlo ◽

Patrizia Pignataro ◽

Francesco Gaccione ◽

Silvia Colucci ◽

...

Keyword(s):

Bone Metabolism ◽

Osteoblastic Differentiation ◽

In Vivo Studies ◽

Peroxisome Proliferator ◽

Sirtuin 3 ◽

Peroxisome Proliferator Activated Receptor ◽

Increased Risk

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) is a protein that promotes transcription of numerous genes, particularly those responsible for the regulation of mitochondrial biogenesis. Evidence for a key role of PGC1α in bone metabolism is very recent. In vivo studies showed that PGC1α deletion negatively affects cortical thickness, trabecular organization and resistance to flexion, resulting in increased risk of fracture. Furthermore, in a mouse model of bone disease, PGC1α activation stimulates osteoblastic gene expression and inhibits atrogene transcription. PGC1α overexpression positively affects the activity of Sirtuin 3, a mitochondrial nicotinammide adenina dinucleotide (NAD)-dependent deacetylase, on osteoblastic differentiation. In vitro, PGC1α overexpression prevents the reduction of mitochondrial density, membrane potential and alkaline phosphatase activity caused by Sirtuin 3 knockdown in osteoblasts. Moreover, PGC1α influences the commitment of skeletal stem cells towards an osteogenic lineage, while negatively affects marrow adipose tissue accumulation. In this review, we will focus on recent findings about PGC1α action on bone metabolism, in vivo and in vitro, and in pathologies that cause bone loss, such as osteoporosis and type 2 diabetes.

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Activation of Peroxisome Proliferator-Activated Receptor γ Does Not Inhibit IL-6 or TNF-α Responses of Macrophages to Lipopolysaccharide In Vitro or In Vivo

The Journal of Immunology ◽

10.4049/jimmunol.164.2.1046 ◽

2000 ◽

Vol 164 (2) ◽

pp. 1046-1054 ◽

Cited By ~ 139

Author(s):

Rolf Thieringer ◽

Judy E. Fenyk-Melody ◽

Cheryl B. Le Grand ◽

Beverly A. Shelton ◽

Patricia A. Detmers ◽

...

Keyword(s):

Peroxisome Proliferator ◽

Peroxisome Proliferator Activated Receptor ◽

Tnf Α

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Suppression of Peroxisome Proliferator-Activated Receptor γ-Coactivator-1α Normalizes the Glucolipotoxicity-Induced Decreased BETA2/NeuroD Gene Transcription and Improved Glucose Tolerance in Diabetic Rats

Endocrinology ◽

10.1210/en.2009-0241 ◽

2009 ◽

Vol 150 (9) ◽

pp. 4074-4083 ◽

Cited By ~ 10

Author(s):

Ji-Won Kim ◽

Young-Hye You ◽

Dong-Sik Ham ◽

Jae-Hyoung Cho ◽

Seung-Hyun Ko ◽

...

Keyword(s):

Glucose Tolerance ◽

Receptor Site ◽

Diabetic Rats ◽

Peroxisome Proliferator ◽

Β Cells ◽

Β Cell ◽

Peroxisome Proliferator Activated Receptor ◽

Cell Dysfunction

Abstract Peroxisome proliferator-activated receptor γ-coactivator-1α (PGC-1α) is significantly elevated in the islets of animal models of diabetes. However, the molecular mechanism has not been clarified. We investigated whether the suppression of PGC-1α expression protects against β-cell dysfunction in vivo and determined the mechanism of action of PGC-1α in β-cells. The studies were performed in glucolipotixicity-induced primary rat islets and INS-1 cells. In vitro and in vivo approaches using adenoviruses were used to evaluate the role of PGC-1α in glucolipotoxicity-associated β-cell dysfunction. The expression of PGC-1α in cultured β-cells increased gradually with glucolipotoxicity. The overexpression of PGC-1α also suppressed the expression of the insulin and β-cell E-box transcription factor (BETA2/NeuroD) genes, which was reversed by PGC-1α small interfering RNA (siRNA). BETA2/NeuroD, p300-enhanced BETA2/NeuroD, and insulin transcriptional activities were significantly suppressed by Ad-PGC-1α but were rescued by Ad-siPGC-1α. PGC-1α binding at the glucocorticoid receptor site on the BETA2/NeuroD promoter increased in the presence of PGC-1α. Ad-siPGC-1α injection through the celiac arteries of 90% pancreatectomized diabetic rats improved their glucose tolerance and maintained their fasting insulin levels. The suppression of PGC-1α expression protects the glucolipotoxicity-induced β-cell dysfunction in vivo and in vitro. A better understanding of the functions of molecules such as PGC-1α, which play key roles in intracellular fuel regulation, could herald a new era of the treatment of patients with type 2 diabetes mellitus by providing protection from glucolipotoxicity, which is an important cause of the development and progression of the disease.

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Irisin in the primate hypothalamus and its effect on GnRH in vitro

Journal of Endocrinology ◽

10.1530/joe-18-0574 ◽

2019 ◽

Vol 241 (3) ◽

pp. 175-187 ◽

Cited By ~ 6

Author(s):

Fazal Wahab ◽

Ikram Ullah Khan ◽

Ignacio Rodriguez Polo ◽

Hira Zubair ◽

Charis Drummer ◽

...

Keyword(s):

Rhesus Monkeys ◽

Peroxisome Proliferator ◽

Developmentally Regulated ◽

Peroxisome Proliferator Activated Receptor ◽

Reproductive Effects ◽

Reproductive Axis ◽

Hypothalamic Cells ◽

Endocrine Factor

Irisin, encoded by the FNDC5 gene, is a recently discovered endocrine factor mainly secreted as a myokine and adipokine. However, irisin/FNDC5 expression has also been reported in different other organs including components of the reproductive axis. Yet, there is the scarcity of data on FNDC5/irisin expression, regulation and its reproductive effects, particularly in primates. Here, we report the expression of FNDC5/irisin, along with PGC1A (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) and ERRA (estrogen-related receptor alpha), in components of the reproductive axis of marmoset monkeys. Hypothalamic FNDC5 and ERRA transcript levels are developmentally regulated in both male and female. We further uncovered sex-specific differences in FNDC5, ERRA and PGC1A expression in muscle and the reproductive axis. Moreover, irisin and ERRα co-localize in the marmoset hypothalamus. Additionally, in the arcuate nucleus of rhesus monkeys, the number of irisin+ cells was significantly increased in short-term fasted monkeys as compared to ad libitum-fed monkeys. More importantly, we observed putative interaction of irisin-immunoreactive fibers and few GnRH-immunoreactive cell bodies in the mediobasal hypothalamus of the rhesus monkeys. Functionally, we noted a stimulatory effect of irisin on GnRH synthesis and release in mouse hypothalamic neuronal GT1-7 cells. In summary, our findings show that FNDC5 and irisin are developmentally, metabolic-status dependently and sex-specifically expressed in the primate hypothalamic–pituitary–gonadal axis and exert a stimulatory effect on GnRH expression and release in mouse hypothalamic cells. Further studies are required to confirm the reproductive effects of irisin in vivo and to illuminate the mechanisms of its regulation.

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