In vitro interaction between resistin and peroxisome proliferator-activated receptor γ in porcine ovarian follicles

2016 ◽  
Vol 28 (3) ◽  
pp. 357 ◽  
Author(s):  
Agnieszka Rak-Mardyła ◽  
Eliza Drwal

In the present study, using real-time polymerase chain reaction and immunoblotting methods, we quantified the expression of peroxisome proliferator-activated receptor (PPAR) γ, PPARα and PPARβ in different sized ovarian follicles (small (SF), medium (MF) and large (LF) follicles) in prepubertal and adult pigs. In prepubertal pigs, PPARγ and PPARα expression was highest in LF; however, PPARβ expression did not differ among SF, MF and LF. In mature pigs, only protein expression of PPARγ and PPARα increased during ovarian follicle development. Following identification of very high levels of PPARγ expression in LF in prepubertal and adult pigs, using in vitro culture of ovarian follicles, we determined the effect of resistin at 0.1, 1 and 10 ng mL–1 on PPARγ mRNA and protein expression and the effect of rosiglitazone at 25 and 50 µM (a PPARγ agonist) on resistin mRNA and protein expression. Resistin increased PPARγ expression in ovarian follicles in both prepubertal and adult pigs, whereas rosiglitazone had an inhibitory effect on resistin expression. The role of PPARγ in regulating the effects of resistin on ovarian steroidogenesis was investigated using GW9662 (a PPARγ antagonist at dose of 1 μM). In these studies, GW9662 reversed the effect of resistin on steroid hormone secretion. The data suggest that there is local cooperation between resistin and PPARγ expression in the porcine ovary. Resistin significantly increased the expression of PPARγ, whereas PPARγ decreased resistin expression; thus, PPARγ is a new key regulator of resistin expression and function.


2003 ◽  
Vol 372 (1) ◽  
pp. 203-210 ◽  
Author(s):  
Zhimin TONG ◽  
Xuli WU ◽  
James P. KEHRER

MK886, a strong proapoptotic agent, is an inhibitor of 5-lipoxygenase (LOX) through binding to the 5-LOX-activating protein (FLAP). Although MK886-induced apoptosis is through a FLAP-independent pathway, the precise mechanisms are not understood. In the present study, a possible role of 24p3, a lipocalin, in MK886-induced apoptosis was investigated. Exposure of murine prolymphoid progenitor cells (FL5.12) to 20 μM MK886 for 16 h dramatically increased 24p3 mRNA and protein expression. Induction could also be achieved with another FLAP inhibitor, MK591. The induction of 24p3 by MK886 was dose- and time-dependent. The up-regulated 24p3 mRNA expression by MK886 was enhanced a further 3.1-fold by WY14643, an activator of peroxisome-proliferator-activated receptor α, whereas ciglitazone, an activator of peroxisome-proliferator-activated receptor γ attenuated the MK886-induced 24p3 expression by more than 50%. Neither WY14643 nor ciglitazone alone had any effect on the expression of 24p3. The induction of 24p3 by MK886 was dependent on the synthesis of new protein(s), since cycloheximide, an inhibitor of protein synthesis, prevented this effect. In all cases, including the inhibition of MK886-induced 24p3 protein expression by stable transfection with antisense cDNA of 24p3, the extent of apoptosis closely paralleled 24p3 levels. Apoptosis induced by MK886, or enhanced by WY14643, was accompanied by the cleavage and activation of caspase-3. The overexpression of bcl-2 or bcl-xL in FL5.12 cells inhibited apoptosis induced by MK886 as well as the enhancement of apoptosis by WY14643. Thus 24p3 is an MK886-inducible gene and may play an important role in MK886-induced apoptosis.



2010 ◽  
Vol 298 (2) ◽  
pp. F381-F390 ◽  
Author(s):  
Ilaria Miceli ◽  
Davina Burt ◽  
Elena Tarabra ◽  
Giovanni Camussi ◽  
Paolo Cavallo Perin ◽  
...  

Increased glomerular permeability to proteins is a characteristic feature of diabetic nephropathy (DN). The slit diaphragm is the major restriction site to protein filtration, and the loss of nephrin, a key component of the slit diaphragm, has been demonstrated in both human and experimental DN. Both systemic and glomerular hypertension are believed to be important in the pathogenesis of DN. Human immortalized podocytes were subjected to repeated stretch-relaxation cycles by mechanical deformation with the use of a stress unit (10% elongation, 60 cycles/min) in the presence or absence of candesartan (1 μM), PD-123319 (1 μM), and rosiglitazone (0.1 μM). Nephrin mRNA and protein expression were assessed using quantitative real-time PCR, immunoblotting, and immunofluorescence, and the protein expression of AT1 receptor and angiotensin II secretion were evaluated. Exposure to stretch induced a significant ∼50% decrease in both nephrin mRNA and protein expression. This effect was mediated by an angiotensin II-AT1 mechanism. Indeed, podocyte stretching induced both angiotensin II secretion and AT1 receptor overexpression, podocyte exposure to angiotensin II reduced nephrin protein expression, and both the AT-1 receptor antagonist candesartan and a specific anti-angiotensin II antibody completely abolished stretch-induced nephrin downregulation. Similar to candesartan, the peroxisome proliferator-activated receptor (PPAR)-γ agonist, rosiglitazone, also inhibited stretch-induced nephrin downregulation, suggesting interference with stretch-induced activation of the angiotensin II-AT1 receptor system. Accordingly, rosiglitazone did not alter stretch-induced angiotensin II secretion, but it prevented AT1 upregulation in response to stretch. These results suggest a role for hemodynamic stress in loss of nephrin expression and allude to a role of PPAR-γ agonists in the prevention of this loss.



2013 ◽  
Vol 124 (11) ◽  
pp. 663-674 ◽  
Author(s):  
Maik Hüttemann ◽  
Icksoo Lee ◽  
Guy A. Perkins ◽  
Steven L. Britton ◽  
Lauren G. Koch ◽  
...  

Alternative approaches to reduce congenital muscle dysfunction are needed in cases where the ability to exercise is limited. (−)-Epicatechin is found in cocoa and may stimulate capillarity and mitochondrial proliferation in skeletal muscle. A total of 21 male rats bred for LCR (low running capacity) from generation 28 were randomized into three groups: vehicle for 30 days (control); (−)-epicatechin for 30 days; and (−)-epicatechin for 30 days followed by 15 days without (−)-epicatechin. Groups 2 and 3 received 1.0 mg of (−)-epicatechin/kg of body mass twice daily, whereas water was given to the control group. The plantaris muscle was harvested for protein and morphometric analyses. In addition, in vitro experiments were conducted to examine the role of (−)-epicatechin on mitochondrial respiratory kinetics at different incubation periods. Treatment for 30 days with (−)-epicatechin increased capillarity (P<0.001) and was associated with increases in protein expression of VEGF (vascular endothelial growth factor)-A with a concomitant decrease in TSP-1 (thrombospondin-1) and its receptor, which remained after 15 days of (−)-epicatechin cessation. Analyses of the p38 MAPK (mitogen-activated protein kinase) signalling pathway indicated an associated increase in phosphorylation of MKK3/6 (MAPK kinase 3/6) and p38 and increased protein expression of MEF2A (myocyte enhancer factor 2A). In addition, we observed significant increases in protein expression of PGC-1α (peroxisome-proliferator-activated receptor γ co-activator 1α), PGC-1β, Tfam and cristae abundance. Interestingly, these increases associated with (−)-epicatechin treatment remained after 15 days of cessation. Lastly, in vitro experiments indicated that acute exposure of LCR muscle to (−)-epicatechin incubation was not sufficient to increase mitochondrial respiration. The results suggest that increases in skeletal muscle capillarity and mitochondrial biogenesis are associated with 30 days of (−)-epicatechin treatment and sustained for 15 days following cessation of treatment. Clinically, the use of this natural compound may have potential application in populations that experience muscle fatigue and are unable to perform endurance exercise.



Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3498
Author(s):  
Michele Longo ◽  
Federica Zatterale ◽  
Jamal Naderi ◽  
Cecilia Nigro ◽  
Francesco Oriente ◽  
...  

Exposure to endocrine-disrupting chemicals such as Bisphenol-A (BPA) is associated with an increase in obesity prevalence. Diet is the primary cause of human exposure to this contaminant. BPA promotes obesity by inducing adipocyte dysfunction and altering adipogenesis. Contradictory evidence and unanswered questions are reported in the literature concerning the BPA effects on adipogenesis. To clarify this issue, we tested the effects of prolonged low-dose BPA exposure on different phases of adipogenesis in committed 3T3L1 and uncommitted NIH3T3 preadipocytes. Our findings show that BPA effects on the adipogenesis are mediated by epigenetic mechanisms by reducing peroxisome proliferator-activated receptor gamma (Pparγ) promoter methylation in preadipocytes. Nevertheless, in BPA-exposed 3T3L1, Pparγ expression only transiently increases as lipid accumulation at day 4 of differentiation, without altering the adipogenic potential of the precursor cells. In the absence of differentiation mix, BPA does not make the 3T3L1 an in vitro model of spontaneous adipogenesis and the effects on the Pparγ expression are still limited at day 4 of differentiation. Furthermore, BPA exposure does not commit the NIH3T3 to the adipocyte lineage, although Pparγ overexpression is more evident both in preadipocytes and during the adipocyte differentiation. Interestingly, termination of the BPA exposure restores the Pparγ promoter methylation and inflammatory profile of the 3T3L1 cells. This study shows that BPA induces epigenetic changes in a key adipogenic gene. These modifications are reversible and do not affect preadipocyte commitment and/or differentiation. We identify an alternative transcriptional mechanism by which BPA affects gene expression and demonstrate how the challenge of preventing exposure is fundamental for human health.



Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Jing Li ◽  
Xiaojie Quan ◽  
Yue Zhang ◽  
Ting Yu ◽  
Saifei Lei ◽  
...  

Exposure to the antibacterial agent triclosan (TCS) is associated with abnormal placenta growth and fetal development during pregnancy. Peroxisome proliferator-activated receptor γ (PPARγ) is crucial in placenta development. However, the mechanism of PPARγ in placenta injury induced by TCS remains unknown. Herein, we demonstrated that PPARγ worked as a protector against TCS-induced toxicity. TCS inhibited cell viability, migration, and angiogenesis dose-dependently in HTR-8/SVneo and JEG-3 cells. Furthermore, TCS downregulated expression of PPARγ and its downstream viability, migration, angiogenesis-related genes HMOX1, ANGPTL4, VEGFA, MMP-2, MMP-9, and upregulated inflammatory genes p65, IL-6, IL-1β, and TNF-α in vitro and in vivo. Further investigation showed that overexpression or activation (rosiglitazone) alleviated cell viability, migration, angiogenesis inhibition, and inflammatory response caused by TCS, while knockdown or inhibition (GW9662) of PPARγ had the opposite effect. Moreover, TCS caused placenta dysfunction characterized by the significant decrease in weight and size of the placenta and fetus, while PPARγ agonist rosiglitazone alleviated this damage in mice. Taken together, our results illustrated that TCS-induced placenta dysfunction, which was mediated by the PPARγ pathway. Our findings reveal that activation of PPARγ might be a promising strategy against the adverse effects of TCS exposure on the placenta and fetus.



Author(s):  
Daniela Soto ◽  
Claudia Martini ◽  
Evelyn Frontera ◽  
Laura Montaldo ◽  
Maria C. Vila ◽  
...  

Aims: Reports regarding the effects of antioxidants in obesity have been contradictory. Antioxidant N-acetylcysteine is usually considered a nutritional supplement. Our aim is to evaluate bioactivity of N-acetylcysteine (NAC) on mature adipocytes, which is a close model to in vivo condition. Study Design: In vitro study. Place and Duration of Study: Department of Basic Science (Universidad Nacional de Lujan), Department of Chemical Biology (Universidad de Buenos Aires), CONICET – INEDES and CONICET – IQUIBICEN, between March 2017 and June 2019. Methodology: We evaluated the bioactivity of different concentrations of NAC for 5 days (0.01 mM to 5 mM) on fully differentiated 3T3-L1 cells (mature adipocytes). Results: We demonstrated that NAC treatment was not toxic to mature adipocytes. Only 5mM NAC inhibited reactive oxygen species production. 5 mM NAC treatment resulted in a 60% decrease in cellular triglycerides content and inhibited 70% cholesterol accumulation.  We also determined the mRNA and protein expression levels of Peroxisome Proliferator-Activated Receptor g as well as, mRNA levels of lipid protein Perilipin in NAC treated adipocytes; we observed that 5mM NAC treatment caused nearly 30% decrease in the expression of these parameters. Conclusion: These results suggest that NAC could avoid lipid accumulation in mature adipocytes; the antioxidant NAC could be beneficial in obesity treatment.



2004 ◽  
Vol 286 (2) ◽  
pp. E208-E216 ◽  
Author(s):  
Shin Terada ◽  
Izumi Tabata

The purpose of this study was to elucidate the mechanisms underlying low-intensity exercise-induced peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) protein expression in rat skeletal muscles. Rats (5–6 wk old) swam without a load and ran on the treadmill at a speed of 13 m/min, respectively, in two 3-h sessions separated by 45 min of rest. PGC-1α content in epitrochlearis muscle (EPI) was increased by 75 and 95%, immediately and 6 h after swimming, respectively, with no increase in PGC-1α content in the soleus (SOL). After running, PGC-1α content in EPI was unchanged, whereas a 107% increase in PGC-1α content was observed in SOL 6 h after running. Furthermore, in EPI and SOL as well as other muscles (triceps, plantaris, red and white gastrocnemius), PGC-1α expression was enhanced concomitant with reduced glycogen postexercise, suggesting that expression of PGC-1α occurs in skeletal muscle recruited during exercise. PGC-1α content in EPI was increased after 18-h in vitro incubation with 0.5 mM 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) and 4 mM caffeine. However, AICAR incubation did not affect PGC-1α content in the SOL, whereas caffeine incubation increased it. These results suggest that exercise-induced PGC-1α expression in skeletal muscle may be mediated by at least two exercise-induced signaling factors: AMPK activation and Ca2+ elevation. The number of factors involved (both AMPK and Ca2+, or Ca2+ only) in exercise-induced PGC-1α expression may differ among muscles.



Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3801 ◽  
Author(s):  
Łukasz Uram ◽  
Maria Misiorek ◽  
Monika Pichla ◽  
Aleksandra Filipowicz-Rachwał ◽  
Joanna Markowicz ◽  
...  

Glioblastoma multiforme (GBM) is the most malignant type of central nervous system tumor that is resistant to all currently used forms of therapy. Thus, more effective GBM treatment strategies are being investigated, including combined therapies with drugs that may cross the blood brain barrier (BBB). Another important issue considers the decrease of deleterious side effects of therapy. It has been shown that nanocarrier conjugates with biotin can penetrate BBB. In this study, biotinylated PAMAM G3 dendrimers substituted with the recognized anticancer agents cyclooxygenase-2 (COX-2) inhibitor celecoxib and peroxisome proliferator-activated receptor γ (PPARγ) agonist Fmoc-L-Leucine (G3-BCL) were tested in vitro on human cell lines with different p53 status: glioblastoma (U-118 MG), normal fibroblasts (BJ) and immortalized keratinocytes (HaCaT). G3-BCL penetrated efficiently into the lysosomal and mitochondrial compartments of U-118 MG cells and induced death of U-118 MG cells via apoptosis and inhibited proliferation and migration at low IC50 = 1.25 µM concentration, considerably lower than either drug applied alone. Comparison of the effects of G3-BCL on expression of COX-2 and PPARγ protein and PGE2 production of three different investigated cell line phenotypes revealed that the anti-glioma effect of the conjugate was realized by other mechanisms other than influencing PPAR-γ expression and regardless of p53 cell status, it was dependent on COX-2 protein level and high PGE2 production. Similar G3-BCL cytotoxicity was seen in normal fibroblasts (IC50 = 1.29 µM) and higher resistance in HaCaT cells (IC50 = 4.49 µM). Thus, G3-BCL might be a good candidate for the targeted, local glioma therapy with limited site effects.



Endocrinology ◽  
2014 ◽  
Vol 155 (1) ◽  
pp. 299-309 ◽  
Author(s):  
Ping He ◽  
Zhaoguang Chen ◽  
Qianqian Sun ◽  
Yuan Li ◽  
Hang Gu ◽  
...  

Placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) is reduced in pregnancies complicated with preeclampsia (PE). Peroxisome proliferator-activated receptors β/δ (PPARβ/δ) have been shown to suppress 11β-HSD2 expression in human placental cells. Our objectives were to investigate whether the reduced 11β-HSD2 expression is associated with the changes in PPARs in PE placentas, and whether PPARα and PPARγ affect 11β-HSD2 expression in placental cells. PPARα and PPARβ/δ mRNA and protein expression was increased, whereas PPARγ mRNA and protein expression was decreased in PE placentas. 11β-HSD2 protein expression was inversely correlated with PPARβ/δ in normal placentas but correlated positively with PPARγ and inversely to PPARα in PE placentas. In cultured placental cells, PPARα agonist inhibited, whereas PPARγ agonist stimulated, 11β-HSD2 mRNA and protein expression and activity in a dose-dependent manner. Knockdown of retinoid X nuclear receptor α (RXRα) resulted in a loss of PPARγ effect but not PPARα effect on11β-HSD2. The PPARα effect remained, but the PPARγ effect was lost in the presence of the translational inhibitor cycloheximide. PPARγ agonist dose-dependently stimulated specificity protein 1 (Sp-1) protein expression. Inhibition or knockdown of Sp-1 resulted in a loss of the effects of PPARα and PPARγ. The Sp-1 protein level was not correlated with 11β-HSD2 and PPARs in normal placentas, whereas Sp-1 expression was correlated with 11β-HSD2, PPARγ, and PPARβ/δ in PE placentas. Our data indicate that 11β-HSD2 expression can be modulated by PPARα and PPARγ in placental trophoblasts through Sp-1. Decreased 11β-HSD2 expression in PE placenta might be associated with decreased PPARγ but increased PPARα expression.



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