scholarly journals Detection and functional characterisation of the transcription factor peroxisome proliferator-activated receptor gamma in lutein cells

1998 ◽  
Vol 159 (3) ◽  
pp. 429-439 ◽  
Author(s):  
B Lohrke ◽  
T Viergutz ◽  
SK Shahi ◽  
R Pohland ◽  
K Wollenhaupt ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Adipogenic Differentiation ◽  
Functional Change ◽  
High Dose ◽  
Peroxisome Proliferator ◽  
Intact Cells ◽  
Peroxisome Proliferator Activated Receptor ◽  
Enhanced Production ◽  
Functional Characterisation ◽  
Peroxisome Proliferator Activated Receptors

A prominent functional change during differentiation of lutein cells from follicular thecal and granulosa cells is an enhanced production and secretion of progestins. The regulation of this process is not fully understood but may be associated with the expression of transcription factors which activate genes, products of which are involved in pathways of the cholesterol and lipid metabolism. As peroxisome proliferator-activated receptors (PPARs) play a role in both pathways, we were interested in the expression of PPARgamma, a PPAR form which is involved in adipogenic differentiation. First, we were able to show the expression of PPARgamma in bovine lutein cells (day 12 of the ovarian cycle) at the mRNA and protein level by imaging, flow cytometry and blot analysis, and secondly a role of PPARgamma in the secretion of progesterone. The cells (24 h culture) responded dose dependently by increasing progesterone secretion (up to 1.5-fold of the basal level) to an endogenous ligand of PPARgamma, 15-deoxy-delta12,14 prostaglandin J2 (15-dPGJ2) and to the thiazolidinedione ciglitizone. Aurintricarboxylic acid (ATA) was found to reduce the intracellular PPARgamma level and to promote cell cycle progress, indicating that ATA can be used as a tool for experimental changes of PPARgamma proteins in intact cells and for studying the physiological consequences. The ATA-mediated decrease of PPARgamma was accompanied by reduced progesterone production and a progression of the cell cycle, suggesting a function of PPARgamma in both processes. The response to ATA was abrogated by a high dose (>490 nM) of 15-dPGJ2, suggesting that 15-dPGJ2 exerts its effect on steroidogenic activity via PPARgamma and that the 15-dPGJ2-PPARgamma system plays a role in the maintenance of a differentiated quiescent stage in lutein cells.

scholarly journals Zidovudine Impairs Adipogenic Differentiation through Inhibition of Clonal Expansion

2008 ◽  
Vol 52 (8) ◽  
pp. 2882-2889 ◽  
Author(s):  
Metodi V. Stankov ◽  
Reinhold E. Schmidt ◽  
Georg M. N. Behrens
Keyword(s):  
Adipogenic Differentiation ◽  
Clonal Expansion ◽  
Inhibitory Effect ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Triglyceride Accumulation ◽  
Thymidine Incorporation Assay ◽  
Human Preadipocytes ◽  
Incorporation Assay ◽  
The Impact

ABSTRACT Lipoatrophy is a prevalent side effect of treatment with thymidine analogues. We wished to confine the time point of the antiadipogenic effect of zidovudine (AZT) during adipogenesis and to evaluate the antiproliferative effect of AZT on adipocyte homeostasis. We investigated the effects of AZT on adipogenesis in 3T3-F442A cells and studied their proliferation, differentiation, viability, and adiponectin expression. Cells were exposed to AZT (1 μM, 3 μM, 6 μM, and 180 μM), stavudine (d4T; 3 μM), or dideoxycytosine (ddC; 0.1 μM) for up to 15 days. Differentiation was assessed by real-time PCR and quantification of triglyceride accumulation. Proliferation and clonal expansion were determined by a [3H]thymidine incorporation assay. When they were induced to differentiate in the presence of AZT at the maximum concentration in plasma (C max) and lower concentrations, 3T3-F442A preadipocytes failed to accumulate cytoplasmic triacylglycerol and failed to express normal levels of the later adipogenic transcription factors, CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor γ. AZT exerted an inhibitory effect on the completion of the mitotic clonal expansion, which resulted in incomplete 3T3-F442A differentiation and, finally, a reduction in the level of adiponectin expression. In addition, AZT impaired the constitutive proliferation in murine and primary human subcutaneous preadipocytes. In contrast, incubation with d4T and ddC at the C max did not affect either preadipocyte proliferation or clonal expansion and differentiation. We conclude that the antiproliferative and antiadipogenetic effects of AZT on murine and primary human preadipocytes reveal the impact of the drug on fat tissue regeneration. These effects of the drug are expected to contribute to disturbed adipose tissue homeostasis and to be influenced by differential drug concentration and penetration in individual patients.

scholarly journals PPARγ Activation Inhibits Growth and Survival of Human Endometriotic Cells by Suppressing Estrogen Biosynthesis and PGE2 Signaling.

Endocrinology ◽  
2013 ◽  
Vol 154 (12) ◽  
pp. 4803-4813 ◽  
Author(s):  
Dan I. Lebovic ◽  
Shahryar K. Kavoussi ◽  
JeHoon Lee ◽  
Sakhila K. Banu ◽  
Joe A. Arosh
Keyword(s):  
Cell Cycle ◽  
Stromal Cells ◽  
Cell Cycle Regulation ◽  
Chronic Inflammatory Disease ◽  
Reproductive Age ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Growth And Survival ◽  
Cycle Regulation ◽  
Estrogen Biosynthesis

Endometriosis is a chronic inflammatory disease of reproductive age women leading to chronic pelvic pain and infertility. Current antiestrogen therapies are temporizing measures, and endometriosis often recurs. Potential nonestrogenic or nonsteroidal targets are needed for treating endometriosis. Peroxisome proliferator-activated receptor (PPAR)γ, a nuclear receptor, is activated by thiazolidinediones (TZDs). In experimental endometriosis, TZDs inhibit growth of endometriosis. Clinical data suggest potential use of TZDs for treating pain and fertility concurrently in endometriosis patients. Study objectives were to 1) determine the effects of PPARγ action on growth and survival of human endometriotic epithelial and stromal cells and 2) identify the underlying molecular links between PPARγ activation and cell cycle regulation, apoptosis, estrogen biosynthesis, and prostaglandin E2 biosynthesis and signaling in human endometriotic epithelial and stromal cells. Results indicate that activation of PPARγ by TZD ciglitazone 1) inhibits growth of endometriotic epithelial cells 12Z up to 35% and growth of endometriotic stromal cells 22B up to 70% through altered cell cycle regulation and intrinsic apoptosis, 2) decreases expression of PGE2 receptors (EP)2 and EP4 mRNAs in 12Z and 22B cells, and 3) inhibits expression and function of P450 aromatase mRNA and protein and estrone production in 12Z and 22B cells through EP2 and EP4 in a stromal-epithelial cell-specific manner. Collectively, these results indicate that PGE2 receptors EP2 and EP4 mediate actions of PPARγ by incorporating multiple cell signaling pathways. Activation of PPARγ combined with inhibition of EP2 and EP4 may emerge as novel nonsteroidal therapeutic targets for endometriosis-associated pain and infertility, if clinically proven safe and efficacious.

scholarly journals Peroxisome Proliferator-Activated Receptor Delta: A Conserved Director of Lipid Homeostasis through Regulation of the Oxidative Capacity of Muscle

PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Pieter de Lange ◽  
Assunta Lombardi ◽  
Elena Silvestri ◽  
Fernando Goglia ◽  
Antonia Lanni ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Oxidative Capacity ◽  
Whole Body ◽  
Lipid Homeostasis ◽  
Peroxisome Proliferator ◽  
Transcriptional Program ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peroxisome Proliferator Activated Receptors ◽  
Metabolic Action

The peroxisome proliferator-activated receptors (PPARs), which are ligand-inducible transcription factors expressed in a variety of tissues, have been shown to perform key roles in lipid homeostasis. In physiological situations such as fasting and physical exercise, one PPAR subtype, PPARδ, triggers a transcriptional program in skeletal muscle leading to a switch in fuel usage from glucose/fatty acids to solely fatty acids, thereby drastically increasing its oxidative capacity. The metabolic action of PPARδ has also been verified in humans. In addition, it has become clear that the action of PPARδ is not restricted to skeletal muscle. Indeed, PPARδ has been shown to play a crucial role in whole-body lipid homeostasis as well as in insulin sensitivity, and it is active not only in skeletal muscle (as an activator of fat burning) but also in the liver (where it can activate glycolysis/lipogenesis, with the produced fat being oxidized in muscle) and in the adipose tissue (by incrementing lipolysis). The main aim of this review is to highlight the central role for activated PPARδ in the reversal of any tendency toward the development of insulin resistance.

scholarly journals Association with Coregulators Is the Major Determinant Governing Peroxisome Proliferator-activated Receptor Mobility in Living Cells

2006 ◽  
Vol 282 (7) ◽  
pp. 4417-4426 ◽  
Author(s):  
Cicerone Tudor ◽  
Jérôme N. Feige ◽  
Harikishore Pingali ◽  
Vidya Bhushan Lohray ◽  
Walter Wahli ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Molecular Mechanisms ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Correlation Spectroscopy ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peroxisome Proliferator Activated Receptors

The nucleus is an extremely dynamic compartment, and protein mobility represents a key factor in transcriptional regulation. We showed in a previous study that the diffusion of peroxisome proliferator-activated receptors (PPARs), a family of nuclear receptors regulating major cellular and metabolic functions, is modulated by ligand binding. In this study, we combine fluorescence correlation spectroscopy, dual color fluorescence cross-correlation microscopy, and fluorescence resonance energy transfer to dissect the molecular mechanisms controlling PPAR mobility and transcriptional activity in living cells. First, we bring new evidence that in vivo a high percentage of PPARs and retinoid X receptors is associated even in the absence of ligand. Second, we demonstrate that coregulator recruitment (and not DNA binding) plays a crucial role in receptor mobility, suggesting that transcriptional complexes are formed prior to promoter binding. In addition, association with coactivators in the absence of a ligand in living cells, both through the N-terminal AB domain and the AF-2 function of the ligand binding domain, provides a molecular basis to explain PPAR constitutive activity.

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