scholarly journals Inhibitory Effects of a Novel PPAR-γ Agonist MEKT1 on Pomc Expression/ACTH Secretion in AtT20 Cells

PPAR Research ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Rehana Parvin ◽  
Erika Noro ◽  
Akiko Saito-Hakoda ◽  
Hiroki Shimada ◽  
Susumu Suzuki ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Cushing’S Disease ◽  
Dna Interaction ◽  
Luciferase Assay ◽  
Cushing's Disease ◽  
Therapeutic Effects ◽  
Peroxisome Proliferator ◽  
Acth Secretion ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

Although therapeutic effects of the peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists rosiglitazone and pioglitazone against Cushing’s disease have been reported, their effects are still controversial and inconsistent. We therefore examined the effects of a novel PPAR-γ agonist, MEKT1, on Pomc expression/ACTH secretion using murine corticotroph-derived AtT20 cells and compared its effects with those of rosiglitazone and pioglitazone. AtT20 cells were treated with either 1 nM~10 μM MEKT1, rosiglitazone, or pioglitazone for 24 hours. Thereafter, their effects on proopiomelanocortin gene (Pomc) mRNA expression were studied by qPCR and the Pomc promoter (−703/+58) activity was demonstrated by luciferase assay. Pomc mRNA expression and promoter activity were significantly inhibited by MEKT1 at 10 μM compared to rosiglitazone and pioglitazone. SiRNA-mediated PPAR-γ knockdown significantly abrogated MEKT1-mediated Pomc mRNA suppression. ACTH secretion from AtT20 cells was also significantly inhibited by MEKT1. Deletion/point mutant analyses of Pomc promoter indicated that the MEKT1-mediated suppression was mediated via NurRE, TpitRE, and NBRE at −404/-383, −316/-309, and −69/-63, respectively. Moreover, MEKT1 significantly suppressed Nur77, Nurr1, and Tpit mRNA expression. MEKT1 also was demonstrated to inhibit the protein-DNA interaction of Nur77/Nurr1-NurRE, Tpit-TpitRE, and Nur77-NBRE by ChIP assay. Taken together, it is suggested that MEKT1 could be a novel therapeutic medication for Cushing’s disease.

scholarly journals Apple Flavonols Mitigate Adipocyte Inflammation and Promote Angiogenic Factors in LPS- and Cobalt Chloride-Stimulated Adipocytes, in Part by a Peroxisome Proliferator-Activated Receptor-γ-Dependent Mechanism

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1386 ◽  
Author(s):  
Danyelle M. Liddle ◽  
Meaghan E. Kavanagh ◽  
Amanda J. Wright ◽  
Lindsay E. Robinson
Keyword(s):  
Mrna Expression ◽  
Cobalt Chloride ◽  
Nuclear Factor Κb ◽  
Diglycidyl Ether ◽  
Low Grade ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Anti Inflammatory

Adipose tissue (AT) expansion induces local hypoxia, a key contributor to the chronic low-grade inflammation that drives obesity-associated disease. Apple flavonols phloretin (PT) and phlorizin (PZ) are suggested anti-inflammatory molecules but their effectiveness in obese AT is inadequately understood. Using in vitro models designed to reproduce the obese AT microenvironment, 3T3-L1 adipocytes were cultured for 24 h with PT or PZ (100 μM) concurrent with the inflammatory stimulus lipopolysaccharide (LPS; 10 ng/mL) and/or the hypoxia mimetic cobalt chloride (CoCl2; 100 μM). Within each condition, PT was more potent than PZ and its effects were partially mediated by peroxisome proliferator-activated receptor (PPAR)-γ (p < 0.05), as tested using the PPAR-γ antagonist bisphenol A diglycidyl ether (BADGE). In LPS-, CoCl2-, or LPS + CoCl2-stimulated adipocytes, PT reduced mRNA expression and/or secreted protein levels of inflammatory and macrophage chemotactic adipokines, and increased that of anti-inflammatory and angiogenic adipokines, which was consistent with reduced mRNA expression of M1 polarization markers and increased M2 markers in RAW 264.7 macrophages cultured in media collected from LPS + CoCl2-simulated adipocytes (p < 0.05). Further, within LPS + CoCl2-stimulated adipocytes, PT reduced reactive oxygen species accumulation, nuclear factor-κB activation, and apoptotic protein expression (p < 0.05). Overall, apple flavonols attenuate critical aspects of the obese AT phenotype.

PPAR-γ ligands modulate effects of LPS in stimulated rat synovial fibroblasts

2002 ◽  
Vol 282 (1) ◽  
pp. C125-C133 ◽  
Author(s):  
Marie-Agnès Simonin ◽  
Karim Bordji ◽  
Sandrine Boyault ◽  
Arnaud Bianchi ◽  
Elvire Gouze ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Constitutive Expression ◽  
Synovial Fibroblasts ◽  
Binding Activity ◽  
Inos Mrna ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Tnf Α ◽  
Cox 2

This work demonstrated the constitutive expression of peroxisome proliferator-activated receptor (PPAR)-γ and PPAR-α in rat synovial fibroblasts at both mRNA and protein levels. A decrease in PPAR-γ expression induced by 10 μg/ml lipopolysaccharide (LPS) was observed, whereas PPAR-α mRNA expression was not modified. 15-Deoxy-Δ12,14-prostaglandin J2(15d-PGJ2) dose-dependently decreased LPS-induced cyclooxygenase (COX)-2 (−80%) and inducible nitric oxide synthase (iNOS) mRNA expression (−80%), whereas troglitazone (10 μM) only inhibited iNOS mRNA expression (−50%). 15d-PGJ2 decreased LPS-induced interleukin (IL)-1β (−25%) and tumor necrosis factor (TNF)-α (−40%) expression. Interestingly, troglitazone strongly decreased TNF-α expression (−50%) but had no significant effect on IL-1β expression. 15d-PGJ2 was able to inhibit DNA-binding activity of both nuclear factor (NF)-κB and AP-1. Troglitazone had no effect on NF-κB activation and was shown to increase LPS-induced AP-1 activation. 15d-PGJ2 and troglitazone modulated the expression of LPS-induced iNOS, COX-2, and proinflammatory cytokines differently. Indeed, troglitazone seems to specifically target TNF-α and iNOS pathways. These results offer new insights in regard to the anti-inflammatory potential of the PPAR-γ ligands and underline different mechanisms of action of 15d-PGJ2 and troglitazone in synovial fibroblasts.

scholarly journals Effects of chronic administration of PPAR-gamma ligand rosiglitazone in Cushing's disease

2004 ◽  
pp. 173-178 ◽  
Author(s):  
B Ambrosi ◽  
C Dall'Asta ◽  
S Cannavo ◽  
R Libe ◽  
T Vigo ◽  
...  
Keyword(s):  
Cushing’S Disease ◽  
Pituitary Tumors ◽  
Chronic Administration ◽  
Ppar Gamma ◽  
Cushing's Disease ◽  
Controlled Study ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Free Cortisol ◽  
Significant Difference

OBJECTIVE: Rosiglitazone, a thiazolidinedione compound with peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-binding affinity, is able to suppress adrenocorticotropic hormone (ACTH) secretion in treated mice and in AtT20 pituitary tumor cells. These observations suggested that thiazolidinediones may be effective as therapy for Cushing's disease (CD). PATIENTS AND METHODS: Rosiglitazone (8 mg/day) was administered to 14 patients with active CD (13 women, one man, 18-68 years). Plasma ACTH, serum cortisol (F) and urinary free cortisol (UFC) levels were measured before and then monthly during rosiglitazone administration. RESULTS: In six patients a reduction of ACTH and F levels and a normalization of UFC were observed 30-60 days after the beginning of rosiglitazone administration: there was a significant difference between basal and post-treatment values for UFC (1238+/-211 vs 154+/-40 nmol/24 h, P<0.03), but not for ACTH (15.9+/-3.7 vs 7.9+/-0.9 pmol/l) and F levels (531+/-73 vs 344+/-58 nmol/l). Two of six cases, followed up for 7 months, showed a mild clinical improvement. Eight patients were nonresponders after 30-60 days of rosiglitazone treatment: their ACTH, F and UFC levels did not differ before and during drug administration. Immunohistochemical analysis of pituitary tumors removed from two responder and two nonresponder patients showed a similar intense immunoreactivity for PPAR-gamma in about 50% of cells. CONCLUSIONS: The administration of rosiglitazone seems able to normalize cortisol secretion in some patients with CD, at least for short periods. Whether the activation of PPAR-gamma by rosiglitazone might be effective as chronic pharmacologic treatment of CD needs a more extensive investigation through a randomized and controlled study.

Correlation of Peroxisome Proliferator-Activated Receptor (PPAR-γ) mRNA Expression with Pro12Ala Polymorphism in Obesity

2013 ◽  
Vol 51 (3-4) ◽  
pp. 256-263 ◽  
Author(s):  
Rym Berhouma ◽  
Soumaya Kouidhi ◽  
Myriam Ammar ◽  
Hafawa Abid ◽  
Hajer Ennafaa ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Peroxisome Proliferator ◽  
Pro12ala Polymorphism ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

scholarly journals Peroxisome Proliferator-Activated Receptor-γ(PPAR-γ) Agonists Attenuate the Profibrotic Response Induced by TGF-β1 in Renal Interstitial Fibroblasts

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Weiming Wang ◽  
Feng Liu ◽  
Nan Chen
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Kidney Diseases ◽  
Smooth Muscle Actin ◽  
Tissue Growth ◽  
Time Dependent ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

Background.Studies have shown that peroxisome proliferator-activated receptor-γ(PPAR-γ) agonists could ameliorate renal fibrotic lesions in both diabetic nephropathy and nondiabetic chronic kidney diseases. In order to elucidate the antifibrotic mechanism of PPAR-γagonists, we investigated the effects of PPAR-γactivation on TGF-β1-induced renal interstitial fibroblasts.Methods.In rat renal interstitial fibroblasts (NRK/49F), the mRNA expression of TGF-β1-inducedα-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF), fibronectin (FN) and collagen type III (Col III) were observed by reverse transcriptase-polymerase chain reaction (RT-PCR). The protein expressions of FN and Smads were observed by Western blot.Results.In NRK/49F, TGF-β1 enhanced CTGF, FN and Col III mRNA expression in a dose- and time-dependent manner.α-SMA, CTGF, FN and Col III mRNA and FN protein expression in 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2)-troglitazone- and ciglitazone-pretreated groups, respectively, were significantly decreased compared with the TGF-β1-stimulated group. TGF-β1 (5 ng/mL) enhanced p-Smad2/3 protein expression in a time-dependent manner. Compared with the TGF-β1-stimulated group, p-Smad2/3 protein induced by TGF-β1 in PPAR-γagonists-pretreated groups significantly decreased with no statistical difference amongst the three pretreated groups.Conclusion.PPAR-γagonists could inhibit TGF-β1-induced renal fibroblast activation, CTGF expression and ECM synthesis through abrogating the TGF-β1/Smads signaling pathway.

scholarly journals Sex-dependent effects of antenatal glucocorticoids on insulin sensitivity in adult sheep: role of the adipose tissue renin angiotensin system

2017 ◽  
Vol 312 (6) ◽  
pp. R1029-R1038 ◽  
Author(s):  
G. Angela Massmann ◽  
Jie Zhang ◽  
Won Joon Seong ◽  
Minhyoung Kim ◽  
Jorge P. Figueroa
Keyword(s):  
Adipose Tissue ◽  
Glucose Tolerance ◽  
Mrna Expression ◽  
Renin Angiotensin System ◽  
Female Offspring ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Pregnant Sheep

Exposure to glucocorticoids in utero is associated with changes in organ function and structure in the adult. The aims of this study were to characterize the effects of antenatal exposure to glucocorticoids on glucose handling and the role of adipose tissue. Pregnant sheep received betamethasone (Beta, 0.17 mg/kg) or vehicle 24 h apart at 80 days of gestation and allowed to deliver at term. At 9 mo, male and female offspring were fed at either 100% of nutritional allowance (lean) or ad libitum for 3 mo (obese). At 1 yr, they were chronically instrumented under general anesthesia. Glucose tolerance was evaluated using a bolus of glucose (0.25 g/kg). Adipose tissue was harvested after death to determine mRNA expression levels of angiotensinogen (AGT), angiotensin-converting enzyme (ACE) 1, ACE2, and peroxisome proliferator-activated receptor γ (PPAR-γ). Data are expressed as means ± SE and analyzed by ANOVA. Sex, obesity, and Beta exposure had significant effects on glucose tolerance and mRNA expression. Beta impaired glucose tolerance in lean females but not males. Superimposed obesity worsened the impairment in females and unmasked the defect in males. Beta increased ACE1 mRNA in females and males and AGT in females only ( P < 0.05 by three-way ANOVA). Obesity increased AGT in females but had no effect on ACE1 in either males or females. PPAR-γ mRNA exhibited a significant sex ( F = 42.8; P < 0.01) and obesity ( F = 6.9; P < 0.05) effect and was significantly higher in males ( P < 0.01 by three-way ANOVA). We conclude that adipose tissue may play an important role in the sexually dimorphic response to antenatal glucocorticoids.

Augmentation of cadmium-induced oxidative cytotoxicity by pioglitazone in renal tubular epithelial cells

2019 ◽  
Vol 35 (8) ◽  
pp. 530-536 ◽  
Author(s):  
Keiko Hosohata ◽  
Nathan Mise ◽  
Fujio Kayama ◽  
Kazunori Iwanaga
Keyword(s):  
Hydrogen Peroxide ◽  
Mrna Expression ◽  
Cell Apoptosis ◽  
Peroxisome Proliferator ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Uptake Pathway ◽  
Renal Tubular

The aim of this study was to examine whether a peroxisome proliferator-activated receptor (PPAR)-γ agonist could affect cadmium (Cd)-induced cytotoxicity via the increased expression of megalin, one of the uptake pathways, using renal epithelial LLC-PK1 cells. The treatment with 1 µM Cd for 24 h was not cytotoxic; however, when the cells were pretreated with 0.1 µM pioglitazone for 12 h and then exposed to 1 µM Cd for 24 h, significant accumulation of Cd and cytotoxicity were detected, with an increase in megalin mRNA expression. In addition, pretreatment with pioglitazone significantly increased the Cd-induced generation of hydrogen peroxide and cell apoptosis. The augmented Cd-induced cytotoxicity and apoptosis on preincubation with pioglitazone were inhibited by prior treatment with GW 9662 (PPAR-γ antagonist). These findings suggest that a PPAR-γ agonist could augment Cd-induced oxidative injury and cell apoptosis, possibly dependent on the expression level of the uptake pathway.

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