Protein Expression Levels Of PPARγ Research Articles

Design, synthesis, 2D-QSAR, molecular dynamic simulation, and biological evaluation of topiramate–phenolic acid conjugates as PPARγ inhibitors

Abstract Background Obesity is a precursor for many co-morbid diseases. One of the main triggering factors for obesity is the abnormal expansion of white adipose tissue characterized by high rates of genesis and differentiation of precursor cells into mature adipocytes. As a result, targeting adipogenesis and adipogenic transcription factors opens new roadmaps for developing novel antiobesity pharmacotherapies. The present study was intended to rationally develop topiramate–phenolic acid conjugate for targeting obesity via inhibition of PPARγ which is often considered as the master regulator of adipogenesis. Results 2D QSAR models were built to foretell PPARγ inhibitory activity of designed conjugates. The models presented excellent robustness, goodness of fit, and predictive capability compounds. The highest PPARγ inhibitory activity was predicted for T3 (topiramate–caffeic acid conjugate) with a pIC50 value of 7.08 µM. Molecular docking was performed for all the designed conjugates against PPARγ (PDB ID: 3VSO). The highest binding affinity was exhibited by T3 (− 11.27 kcal/mol) and displayed strong and stable interactions with the receptor within the allosteric pocket in comparison to the irreversible PPARγ antagonist, GW9662 (binding affinity, − 9.0 kcal/mol). These results were confirmed by subjecting the best-docked molecules to molecular dynamic simulations. The PPARγ–T3 complex was observed to be most stable with maximum number of hydrogen bonds (maximum observed RMSD = 0.57 Å at 100 ns) in comparison to PPARγ–topiramate and PPARγ–caffeic acid complexes. Consequently, T3 was synthesized and further subjected to in vitro screening. The TR-FRET assay established T3 as a PPARγ antagonist (IC50 = 6.78 µM). T3 also significantly reduced the lipid buildup in the 3T3-L1 adipocytes in a dose-dependent manner. In addition, T3 also reduced the protein expression levels of PPARγ as evidenced from western blot results. Conclusions Studies clearly indicated that T3 reduces adipose tissue cell differentiation by downstreaming PPARγ expression at protein levels, thereby emerging as a novel scaffold for antiobesity pharmacotherapy. Graphical abstract

Hypolipidemic Effect of Rice Bran Oil Extract Tocotrienol in High-Fat Diet-Induced Hyperlipidemia Zebrafish (Danio Rerio) Induced by High-Fat Diet.

In recent years, the potent influence of tocotrienol (T3) on diminishing blood glucose and lipid concentrations in both Mus musculus (rats) and Homo sapiens (humans) has been established. However, the comprehensive exploration of tocotrienol's hypolipidemic impact and the corresponding mechanisms in aquatic species remains inadequate. In this study, we established a zebrafish model of a type 2 diabetes mellitus (T2DM) model through high-fat diet administration to zebrafish. In the T2DM zebrafish, the thickness of ocular vascular walls significantly increased compared to the control group, which was mitigated after treatment with T3. Additionally, our findings demonstrate the regulatory effect of T3 on lipid metabolism, leading to the reduced synthesis and storage of adipose tissue in zebrafish. We validated the expression patterns of genes relevant to these processes using RT-qPCR. In the T2DM model, there was an almost two-fold upregulation in pparγ and cyp7a1 mRNA levels, coupled with a significant downregulation in cpt1a mRNA (p < 0.01) compared to the control group. The ELISA revealed that the protein expression levels of Pparγ and Rxrα exhibited a two-fold elevation in the T2DM group relative to the control. In the T3-treated group, Pparγ and Rxrα protein expression levels consistently exhibited a two-fold decrease compared to the model group. Lipid metabolomics showed that T3 could affect the metabolic pathways of zebrafish lipid regulation, including lipid synthesis and decomposition. We provided experimental evidence that T3 could mitigate lipid accumulation in our zebrafish T2DM model. Elucidating the lipid-lowering effects of T3 could help to minimize the detrimental impacts of overfeeding in aquaculture.

Effect of acupuncture on arthritic pathological injury in rats with type Ⅱ collagen-induced rheumatoid arthritis.

To observe the effect of acupuncture stimulation of "Yanglingquan"(GB34), "Zusanli"(ST36) and "Xuanzhong" (GB39) on arthritis index (AI), joint synovial membrane pathology, serum-related immunoinflammatory factors, and expressions of tumor suppressor gene mt-p53, nuclear factor kappa B (NF-κB) and peroxisome proliferator activated receptor gamma (PPARγ) in knee joint synovial tissue of rats with type Ⅱ collagen-induced arthritis (CIA), so as to explore its possible mechanisms underlying improvement of rheumatoid arthritis (RA). Male SD rats were used in the present study. The CIA model was established by subcutaneous injection of collagen emulsion (200 μL/rat) in the tail root region on the first day and repeat (100 μL/rat) once on the 9th day. Eighteen successful CIA rats were randomized into model, medication and acupuncture groups, with 6 rats in each group. Other 6 normal rats were used as the normal control group. For rats of the medication group, leflunomide (1.9 mg/kg) was administrated by gavage, once a day, and for rats of the acupuncture group, manual acupuncture stimulation was applied to bilateral GB34, ST36, GB39 for 30 min, once a day, for 12 weeks. The arthritis index (AI) score (0-4 points) was evaluated once every week. The contents of IL-6, IL-17 and TNF-α in the serum were determined by ELISA. Histopathological changes of the ankle joint were observed by H.E. staining. The protein and mRNA expression levels of mt-p53, NF-κB p65, and PPARγ in the knee joint synovial tissue were determined by Western blot and quantitative real time PCR, separately. Compared with the normal control group, the AI scores at different time-points after modeling, contents of serum TNF-α, IL-6 and IL-17, expression levels of mt-p53, NF-κB p65, PPARγ proteins and mRNAs were significantly increased in the model group (P<0.01, P<0.05). In comparison with the model group, the AI scores at the 10th week in the medication group and at the 3rd, 9th and 10th week in the acupuncture group, contents of serum TNF-α, IL-6 and IL-17, and the expression levels of mt-p53 and NF-κB p65 proteins in both medication and acupuncture groups, as well as mt-p53 and NF-κB p65 mRNAs in the medication group were apparently decreased (P<0.01, P<0.05), while the expression levels of PPARγ protein in both medication and acupuncture group and PPARγ mRNA in the medication group were significantly up-regulated (P<0.05, P<0.01). No significant differences were found between the acupuncture and medication groups in down-regulating the AI score and serum TNF-α, IL-6 and IL-17 contents. The effect of acupuncture was weaker than that of medication in down-regulating the expression of mt-p53 and NF-κB p65 proteins and mRNAs and in up-regulating PPARγ mRNA (P<0.01). H.E. results showed ankle cartilage hyperplasia, reduced joint cavity, mild fibroproliferation and inflammatory cell infiltration in the surrounding soft tissue of the ankle joint in rats of the model group, which was milder in both medication and acupuncture groups. Acupuncture stimulation can improve the degree of joint inflammation and swelling in CIA rats, which may be related to its effects in inhibiting the overexpression of immunoinflammatory factors in serum and regulating expression of mt-p53, NF-κB p65, PPARγ mRNAs and proteins in the synovial tissue.

A convenient and time-saving method for primary culture of mature white adipocytes from mice

To establish a simple, low-cost and time-saving method for primary culture of mature white adipocytes from mice. Mature white adipocytes were isolated from the epididymis and perirenal area of mice for primary culture using a modified mature adipocyte culture method or the ceiling culture method. The morphology of the cultured mature adipocytes was observed using Oil Red O staining, and the cell viability was assessed with CCK8 method. The expression of PPARγ protein in the cells was detected with Western blotting, and the mRNA expressions of CD36, FAS, CPT1A and FABP4 were detected using RT-qPCR. Oil Red O staining showed a good and uniform morphology of the adipocytes in primary culture using the modified culture method, while the cells cultured using the ceiling culture method exhibited obvious morphological changes. CCK8 assay showed no significant difference in cell viability between freshly isolated mature white adipocytes and the cells obtained with the modified culture method. Western blotting showed that the freshly isolated adipocytes and the cells cultured for 72 h did not differ significantly in the expression levels of PPARγ protein (P=0.759), which was significantly lowered in response to treatment with GW9662 (P < 0.001). GW9662 treatment of the cells upregulated mRNA expressions of CD36 (P < 0.001) and CPT1A (P=0.003) and down-regulated those of FAS (P=0.001) and FABP4 (P < 0.001). We established a convenient and time-saving method for primary culture mature white adipocytes from mice to facilitate further functional studies of mature adipocytes.

Effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/β-catenin/PPARγ pathway in arrhythmic rats

This paper aimed to investigate the effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/β-catenin/peroxisome proliferator-activated receptor γ(PPARγ) pathway in arrhythmic rats. SD rats were randomly divided into a control group, a model group, a low-dose(20 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a medium-dose(40 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a high-dose(80 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a propranolol hydrochloride(2 mg·kg~(-1)) group, with 12 rats in each group. Except the control group, rats in other groups were prepared as models of arrhythmia by sublingual injection of 1 mL·kg~(-1) of 0.002% aconitine. After grouping and intervention with drugs, the arrhythmia, myocardial cells apoptosis, myocardial tissue glutathione peroxidase(GSH-Px), catalase(CAT), malondialdehyde(MDA), serum interleukin-6(IL-6), prostaglandin E2(PGE2) levels, myocardial tissue apoptosis, and Wnt/β-catenin/PPARγ pathway-related protein expression of rats in each group were measured. As compared with the control group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA levels in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels increased significantly in the model group, whereas the GSH-Px and CAT levels, and Bcl-2 and PPARγ protein expression levels in myocardial tissues reduced significantly. As compared with the model group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA leve in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels reduced in the drug intervention groups, whereas the GSH-Px and CAT levels and Bcl-2 and PPARγ protein expression levels in myocardial tissues increased. The groups of total flavonoids of buckwheat flower and leaf were in a dose-dependent manner. There was no significant difference in the levels of each index in rats between the propranolol hydrochloride group and the high-dose group of total flavonoids of buckwheat flower and leaf. The total flavonoids of buckwheat flower and leaf inhibit the activation of Wnt/β-catenin pathway, up-regulate the expression of PPARγ, reduce oxidative stress and inflammatory damage in myocardial tissues of arrhythmic rats, reduce myocardial cell apoptosis, and improve the symptoms of arrhythmia in rats.

Overexpression of DGAT2 Stimulates Lipid Droplet Formation and Triacylglycerol Accumulation in Bovine Satellite Cells.

Simple SummaryTriacylglycerols are the major component of intramuscular fat, and the final step in their biosynthesis is catalyzed by DGAT2. Bovine skeletal muscle satellite cells were infected with the overexpression adenovirus Ad-DGAT2 and interfering adenovirus sh-DGAT2. The results showed that overexpression of DGAT2 upregulated the expression of genes involved in lipid accumulation and adipogenesis and increased cellular triacylglycerol content. The differentially expressed genes were mainly enriched in the PPAR signaling, glycerolipid metabolism, fatty acid biosynthesis, and AMPK signaling pathways. These results highlight the important regulatory role of DGAT2 during adipogenic transdifferentiation of BSCs and the complexity of intramuscular adipogenesis, as well as providing a theoretical basis for producing high marbling content beef.Intramuscular fat (IMF) is closely related to the tenderness, juiciness, and flavor of beef, and is an important indicator for beef quality assessment internationally. The main components of skeletal intramuscular fat (IMF) are phospholipids and triacylglycerols (TAG), and the final step of TAG biosynthesis is catalyzed by diacylglycerol acyltransferase 2 (DGAT2). To explore the effect of DGAT2 on the differentiation of bovine muscle satellite cells (BSCs) and its role in the signaling pathway related to lipid metabolism, the adenovirus overexpression and interference vector of the DGAT2 gene was constructed in this study, and the overexpression adenovirus Ad-DGAT2 and interfering adenovirus sh-DGAT2 were used to infect BSCs. Overexpression of DGAT2 resulted in a significant increase in the contents of TAG and ADP, and the mRNA and protein expression levels of PPARγ, C/EBPα, and SREBF1 (p < 0.05). Interfering with the expression of DGAT2 reduced the intracellular TAG content and lipid droplet accumulation. Furthermore, the mRNA and protein expression levels of PPARγ, C/EBPα, and SREBF1 (p < 0.05) were significantly downregulated. Transcriptome sequencing showed that a total of 598 differentially expressed genes (DEGs) were screened in BSCs infected with Ad-DGAT2, and these DEGs included 292 upregulated genes and 306 downregulated genes. A total of 49 DEGs were screened in BSCs infected with sh-DGAT2, and these DEGs included 25 upregulated and 24 downregulated genes. KEGG enrichment analysis showed that the DEGs, after overexpression of DGAT2, were mainly enriched in the PPAR signaling pathway, and the fat digestion and absorption, glycerophospholipid metabolism, fatty acid biosynthesis, and AMPK signaling pathways. The DEGs obtained after interfering with DGAT2 were mainly enriched in the metabolic pathways, such as the PPAR signaling pathway and PI3K/AKT signaling pathway. In summary, our study demonstrated that the lipid droplet formation, TAG accumulation, and adipogenic gene expression in BSCs overexpressing DGAT2 were higher than those in the control cells. These results highlight the important role of DGAT2 in regulating BSCs during adipogenic transdifferentiation and underscore the complexity of intramuscular adipogenesis.

Study on the role of heat shock protein 90 (HSP90) gene in chicken preadipocytes proliferation and differentiation

In this study, we examined the effects of Heat Shock Protein 90 (HSP90) on adipocyte proliferation and differentiation in chickens. To achieve this, we constructed RNA interference (RNAi) vectors to target HSP90 and transfected the vectors into primary adipocytes. After transfection, oil red O staining was performed to determine the status of triglyceride accumulation in the cells, whereas the CCK-8 cell kit and 5-Ethynyl-2'-Deoxyuridine (EdU) assays were used to determine cell proliferation. Thereafter, the mRNA and protein expression levels of PPARγ, FAS, SREBP-1c, and HSP90 were determined, and the results showed that after the interference of HSP90, the mRNA and protein expression levels of HSP90 in the chicken adipocytes decreased significantly compared to the control and blank groups (p < 0.05). The decreased mRNA and protein expression of PPARγ, FAS, and SREBP-1c was related to adipocyte differentiation (p < 0.05). However, HSP90 interference had no effect on adipocyte proliferation (p > 0.05). Taken together, the results of this study showed that HSP90 influenced the expression of PPARγ and adipose-differentiation-related genes, thereby regulating triglyceride accumulation and adipocyte differentiation in chickens.

Metabolites of oregano (Origanum vulgare) seed and their anti-obesity effects on 3T3-L1 adipocytes through down-regulated adipogenesis.

Metabolites of the 80% ethanol extract (OSE) and ethyl acetate fraction (OSEA) of oregano seed were analyzed by GC-MS, and anti-obesity effects of OSE and OSEA were evaluated in 3T3-L1 adipocyte. OSE possessed high content of glucose, fructofuranose, and sucrose while OSEA had high content of phenolic chemicals. OSEA contained higher levels of gallic acid, syringic acid, protocatechuic acid, and catechin than OSE. OSEA inhibited lipid droplet accumulation with concentration dependent manner in 3T3-L1 preadipocytes during differentiation. OSEA showed more inhibition ability than OSE by 13.7-fold at the level of 125μg/mL. Additionally, relative mRNA and protein expression levels of pparγ, c/ebpα, fas, and srebp-1c which are related to adipogenesis were significantly lower in OSEA treatment group than in OSE treatment group (p < 0.05). Therefore, OSEA could be used as anti-obesity functional ingredient.

Ocular expression of cyclin-dependent kinase 5 in patients with proliferative diabetic retinopathy.

ABSTRACTAims/IntroductionInhibition of peroxisome proliferator‐activated receptor gamma (PPARγ) phosphorylation mediated by cyclin‐dependent kinase 5 (Cdk5) is one of the main mechanisms of action of antidiabetic drugs. In this study, we analyzed the ocular expression and activation of Cdk5 in patients with proliferative diabetic retinopathy (PDR).Materials and MethodsThe concentrations of PPARγ, Cdk5 and its activating subunit (p35) were determined in the vitreous body of 24 PDR and 63 control eyes by enzyme‐linked immunosorbent assay. In addition, the messenger ribonucleic acid and protein expression levels of PPARγ, Cdk5 and p35 were measured in proliferative neovascular membranes from seven PDR eyes and non‐neovascular epiretinal membranes from five control eyes by quantitative real‐time polymerase chain reaction and immunohistochemical analysis.ResultsPPARγ, Cdk5 and p35 concentrations in the vitreous body were significantly higher in the PDR group compared with the control group. There was also a positive significant correlation of Cdk5 with PPARγ and p35 in the PDR group. Furthermore, the messenger ribonucleic acid expression levels of PPARγ, Cdk5 and p35 in proliferative neovascular membranes were significantly higher in the PDR group compared with the control group. Immunostaining showed increased protein expression levels of PPARγ, Cdk5 and p35 in proliferative neovascular membranes in the PDR group compared with the control group.ConclusionsCdk5 activation is involved in PDR pathogenesis through PPARγ expression, and inhibition of Cdk5‐mediated PPARγ phosphorylation might be a new therapeutic target for treatment of PDR.

LncRNA MEG3 modulates hepatic stellate cell activation by sponging miR‑145 to regulate PPARγ.

It is important to determine the mechanism of liver fibrosis for targeted therapy and the development of targeted therapies for liver fibrosis may offer promise for patients with liver disease. Long non-coding RNAs (lncRNAs) serve a role in hepatic fibrosis. The lncRNA maternally expressed gene 3 (MEG3) has been confirmed to inhibit liver fibrosis. The present study investigated the role of the MEG3 in healthy patients and patients with liver fibrosis. The expression levels of MEG3 and microRNA (miR)-145 in the serum of healthy volunteers and patients with liver fibrosis and in LX-2 cells were detected using reverse transcription-quantitative PCR. A dual-luciferase reporter assay was used to determine the targeting relationship between MEG3 and miR-145, and the targeting relationship between miR-145 and peroxisome proliferator-activated receptor γ (PPARγ). The protein expression levels of PPARγ, α-smooth muscle actin (α-SMA) and collagen I (COL1A1) were detected using western blotting. The expression levels of α-SMA and COL1A1 were also determined using immunofluorescence. Finally, a Cell Counting Kit-8 assay was performed to assess the proliferative ability of LX-2 cells. A significantly reduced MEG3 expression level was demonstrated in serum from patients with liver fibrosis compared with serum from healthy controls. TGF-β1 induced a significantly decreased MEG3 expression level in LX-2 human hepatic stellate cells in vitro. The TGF-β1-induced increases in cell proliferation and α-SMA and COL1A1 protein expression levels were reversed following MEG3 overexpression. The results also demonstrated that MEG3 sponged miR-145 and competed endogenously with miR-145 to regulate PPARγ. In summary, the present study identified MEG3 as an anti-fibrotic lncRNA and provided new information regarding the role of MEG3 in liver fibrosis. MEG3 may therefore be a potential target in the treatment of liver fibrosis.

Septin 4 activates PPARγ/LXRα signaling by upregulating ABCA1 and ABCG1 expression to inhibit the formation of THP-1 macrophage-derived foam cells.

Septin 4 is a member of a family of GTP-binding proteins that has been previously reported regulate cytoskeletal organization. In addition, it has been suggested to serve a role in atherosclerosis. Therefore, the present study aimed to investigate the effects of Septin 4 on foam cell formation. THP-1 cells were first exposed to phorbol-12-myristate-13-acetate for differentiation into macrophages before being transformed into foam cells by treatment with oxidized low-density lipoprotein (ox-LDL). Septin 4 expression was then knocked down or overexpressed in THP-1 cells using transfection, whilst peroxisome proliferator activated receptor γ (PPARγ) was also inhibited using its selective antagonist (T0070907) in the presence of Septin 4 overexpression. Oil red staining was used to detect lipid uptake, and total cholesterol (TC), free cholesterol (FC) and ATP binding cassette subfamily A/G member 1 (ABCA1/G1) protein expression were also measured. The results demonstrated that upon ox-LDL stimulation, macrophages that were derived from THP-1 cells transformed into foam cells, where Septin 4 was highly expressed in ox-LDL-induced foam cells. Septin 4 knockdown promoted TC and FC levels, but reduced ABCA1/G1 protein expression. The protein expression levels of PPARγ and liver X receptor α (LXRα) were also decreased after Septin 4 knockdown. However, Septin 4 overexpression resulted in the opposite results being observed. Additionally, blocking PPARγ activity using its inhibitor T0070907 or knocking down LXRα expression using short hairpin RNA reversed the effects of Septin 4 overexpression on foam cell formation and cholesterol handling. In conclusion, Septin 4 may serve an important role in preventing foam cell formation by activating PPARγ/LXRα signaling and subsequently enhancing ABCA1/G1 expression.

Effects of PPARγ agonist pioglitazone on cardiac fibrosis in diabetic mice by regulating PTEN/AKT/FAK pathway.

The aim of this study was to explore the role of pioglitazone (PIO), a peroxisome proliferator-activated receptor-gamma (PPARγ) agonist, in cardiac fibrosis of diabetic mice. A total of 60 adult male C57/B6 mice were divided into 3 groups using a random number table, namely, control group (Sham group, n=20), diabetic cardiomyopathy group (DCM group, n=20), DCM + PIO group (n=20). Streptozocin (STZ) was injected into mice at a dose of 125 mg/Kg to induce the model of diabetes in vivo. After successful induction, mice in DCM + PIO group were intragastrically given PIO at 10 mg/kg/d once a day for 6 weeks. Meanwhile, those in Sham group and DCM group were given the same volume of normal saline. After 6 weeks, ejection fraction % (EF%), fraction shortening % (FS%) and heart rate of mice in each group were examined via echocardiography. Picrosirius red (PSR) staining assay was conducted to detect collagen deposition in myocardial tissues of mice in each group. The protein expression level of PPARγ in mouse myocardial tissues in each group was measured through Western blotting and immunohistochemical staining assays. Hematoxylin-eosin (H&E) staining assay was carried out to evaluate the myocardial hypertrophy of mice in each group. The protein expression level of transforming growth factor-β (TGF-β) in mouse myocardial tissues in each group was measured through immunohistochemical staining assay. In addition, Western blotting was employed to detect the expression of proteins related to the phosphate and tension homology deleted on chromsome ten (PTEN)/protein kinase B (AKT)/focal adhesion kinase (FAK) signaling pathway in myocardial tissues of mice in each group. The messenger ribonucleic acid (mRNA) and protein expression levels of PPARγ in mouse myocardial tissues were significantly lower in DCM group than those in Sham group (p<0.05). PPARγ agonist PIO could significantly increase the protein expression of PPARγ in myocardial tissues of DCM mice. The results of cardiac Doppler ultrasound revealed that PIO significantly upregulated EF% and FS% in DCM mice (p<0.05). Besides, PIO remarkably reduced collagen deposition and TGF-β protein expression in myocardial tissues in DCM mice (p<0.05). H&E staining results showed that PIO notably attenuated myocardial hypertrophy in DCM mice (p<0.05). Furthermore, it was discovered that PIO markedly elevated PTEN protein in myocardial tissues of DCM mice and inhibited the phosphorylation of AKT and FAK proteins (p<0.05). The protective effect of PIO against cardiac fibrosis in diabetic mice may be related to its regulation on the PTEN/AKT/FAK signaling pathway. Our findings suggest that PIO is expected to become a targeted drug for the treatment of DCM in clinical practice.

Ginsenoside rg3 reduces body weight by regulating fat content and browning in obese mice

To determine the effects of ginsenoside rg3 on the body weight of C57BL/6J obese mice and to investigate its underlying weight loss mechanisms with a focus on white fat browning-related factors. Eight-week-old C57BL/6J male mice were fed a high-fat diet for 12 successive weeks to construct the obese model. C57BL/6J male mice were fed a standard chow diet to construct normal control group. After 8 weeks of intervention with ginsenoside rg3, the food intake, body weight, body fat mass, blood sugar, and lipid profiles of the mice in each group were detected. Hematoxylin and eosin (HE) staining was used to observe the histological morphology of the adipose tissues. Real-time polymerase chain reaction (RT-PCR) and Western blotting (WB) were applied to detect the gene and protein expression levels of peroxisome proliferators-activated receptor gama (PPARγ), Peroxisome proliferator-activated receptor-gamma coactivator -1alpha (PGC-1α), PR domain containing 16 (PRDM16), and uncoupling protein 1 (UCP-1). Compared to normal control group mice, the body weight, food intake, body fat composition, and blood lipid levels of model group mice increased significantly. After 8 weeks of intervention with ginsenoside rg3, body weight, body fat composition, food intake, and blood lipid profiles decreased. HE staining showed that ginsenoside rg3 can improve white adipocyte hypertrophy to a certain extent. RT-PCR and WB demonstrated that ginsenoside rg3 can increase the mRNA and protein expression levels of PPARγ, PGC-1α, PRDM16, and UCP-1 in the adipose tissues of obese mice. The weight reduction effect of ginsenoside rg3 may be related to the promotion of white fat browning.

Effect of salvianolic acid B on high-glucose induced renal tubular epithelial-mesenchymal transition in rats and its mechanism

The aim of this paper was to observe the effect of salvianolic acid B(Sal B) on high-glucose induced renal tubular epithelial-mesenchymal transition(EMT) in rats, and to explore its possible mechanisms of prevention and treatment of diabetic nephropathy. The rat renal tubular epithelial NRK-52 E cells were cultured in vitro. The cells were divided into control group, high glucose group, high glucose+10 μmol·L~(-1)Sal B group(Sal B), the above 3 groups were set at 6, 12, 24 and 48 h for dynamic observation; high glucose+Sal B different concentration(1, 5, 10 μmol·L~(-1)) groups, high glucose+5.0 μmol·L~(-1) pioglitazone group, high glucose+10 μmol·L~(-1)Sal B+5 μmol·L~(-1)GW9662 group. The protein expression levels of PPARγ, PTEN, α-SMA, E-cadherin and PI3 K/Akt signaling molecules were determined by Western blot. The mRNA expression of PPARγ and PTEN were detected by Real-time PCR. The viabi-lity of NRK52 E cells was determined by MTT assay. The results showed that as compared with control group, the mRNA and protein expression levels of PPARγ and PTEN in high glucose group gradually reduced, the protein expression levels of α-SMA and p-Akt~((Thr308))gradually increased, and the protein expression of E-cadherin gradually reduced(P&lt;0.05). As compared with high glucose group, when increases in Sal B doses, the mRNA and protein expression levels of PPARγ, PTEN in high glucose + different concentrations of Sal B groups gradually increased, the protein expression levels of α-SMA and p-Akt~((Thr308)) gradually reduced, and the protein expression of E-cadherin gradually increased(P&lt;0.05), however, the effect of 1 μmol·L~(-1)concentration of Sal B on the expression of PPARγ mRNA and protein and PTEN mRNA was not significantly different. As compared with high glucose group, the mRNA and protein expression levels of PPARγ mRNA(except 6 h) and protein(except 6 h), PTEN mRNA(except 6 h) and protein(except 6, 12 h) kept increasing, the protein expression levels of α-SMA and p-Akt~((Thr308))(except 6 h) continued to reduce, the protein expression of E-cadherin kept increasing in high glucose+10 μmol·L~(-1) Sal B dynamic observation group(P&lt;0.05). As compared with high glucose group, Sal B and the pioglitazone(PIO) can greatly enhance the expression of PPARγ, PTEN at mRNA and protein levels, enhance the expression of E-cadherin at protein levels, and reduce the expression of α-SMA, p-Akt~((Thr308))protein level(P&lt;0.05), there was no significant difference between the two groups. However, the expression levels of PPARγ and PTEN mRNA and protein, E-cadherin, α-SMA and p-Akt(Thr308) protein in the Sal B+GW9662 control group were not statistically significant compared with the high glucose group. The effect of Sal B was blocked by the PPARγ antagonist GW9662. It can be concluded that Sal B can suppress the NRK52 E cells induced by high-glucose EMT. The mechanism may be related to the activation of PPARγ with Sal B, and the up-regulation of PTEN expression, and thereby inhibiting the fibrosis effect of PI3 K/Akt signaling pathway.

Anticancer effects and possible mechanisms of lycopene intervention on N-methylbenzylnitrosamine induced esophageal cancer in F344 rats based on PPARγ1

Lycopene, a natural carotenoid, has potential chemopreventive effects in many cancers. This study aimed to examine the effects of lycopene on regulating the inflammation and apoptosis of N-nitrosomethylbenzylamine(NMBzA) induced esophageal cancer in F344 rats. After the rats were fed normal diets containing different concentrations of lycopene for 25 weeks (10, 25, 50 mg/kg·d of lycopene, respectively), the incidence of tumors in the rats treated with lycopene was significantly lower than that in the simple exposed group (P < 0.05). The antioxidant activity of lycopene was exerted by measuring the levels of GSH-PX, SOD and MDA activity by oxidative stress kits. Furthermore, through western blotting analysis lycopene intervention was found to have significantly improved apoptosis cytokines by increasing the protein expression levels of PPARγ and caspase-3, and also significantly reduced inflammatory cytokines by decreasing the protein expression of NF-κB and COX-2 in the esophagus tissue, especially in the 25 mg/kg of lycopene intervention group (all P < 0.05). These results demonstrated that appropriate dose of lycopene intervention could inhibit the carcinogenesis of esophageal in F344 rats through the possible mechanisms of anti-inflammatory and pro-apoptosis.

The protective effect of PPARγ in sepsis-induced acute lung injury via inhibiting PTEN/β-catenin pathway.

The present study aims to reveal the molecular mechanism of peroxisome proliferator-activated receptor γ (PPARγ) on sepsis-induced acute lung injury (ALI). To do that, the rat injury model was established using cecal ligation and perforation (CLP) method, followed by different treatments, and the rats were divided into Sham group, CLP group, CLP + rosiglitazone (PPARγ agonist) group, CLP + GW9662 (PPARγ inhibitor) group, CLP + bpV (phosphatase and tensin homolog (PTEN) inhibitor) group, CLP + GW9662 + bpV group. Compared with Sham group, the mRNA and protein expression levels of PPARγ were down-regulated, the inflammation levels were elevated, and the apoptosis was increased in CLP group. After treatment with rosiglitazone, the protein expression level of PPARγ was significantly up-regulated, the phosphorylation level of PTEN/β-catenin pathway was decreased, the PTEN/β-catenin pathway was inhibited, the lung injury, inflammation and apoptosis were reduced. The opposite effect was observed after treatment with GW9662. Besides, bpV inhibited PTEN/β-catenin pathway, and relieved the lung tissue injury. The overexpression of PPARγ reduced inflammatory response and inhibited apoptosis in sepsis-induced ALI. Furthermore, PPARγ relieved the sepsis-induced ALI by inhibiting the PTEN/β-catenin pathway.

Effects of an ethyl acetate extract of Daphne altaica stem bark on the cell cycle, apoptosis and expression of PPARγ in Eca‑109 human esophageal carcinoma cells.

Daphne altaica Pall. (D. altaica; Thymelaeaceae) has long been used in traditional Kazakh medicine for the treatment of cancer and respiratory diseases. Previous studies have demonstrated the in vitro anticancer effects of D. altaica extract and its constituents in certain cancer cell lines; however, the underlying molecular mechanisms are not completely understooD. The present study aimed to investigate the molecular mechanisms underlying the activity of an ethyl acetate extract of D. altaica (Da-Ea) by assessing its effects on cell morphology, cell apoptosis, cell cycle progression and the expression levels of peroxisome proliferator-activated receptor γ (PPARγ) in Eca-109 cells. Cell morphology was observed under a phase contrast microscope. Cell apoptosis and cell cycle progression were assessed by flow cytometry following Annexin V/propidium iodide (PI) double staining and PI single staining, respectively. The mRNA and protein expression levels of PPARγ were determined by reverse transcription-quantitative PCR and western blotting, respectively. Compared with the control group, the percentage of apoptotic cells, cell cycle arrest at S phase and apoptotic morphological cell characteristics were increased in Da-Ea-treated Eca-109 cells. Furthermore, Da-Ea treatment upregulated the mRNA and protein expression levels of PPARγ compared with the control cells. High-performance liquid chromatography with diode-array detection indicated that daphnetin-7-O-β-D-glucoside, daphnetin, demethyldaphnoretin-7-O-β-D-glucopyranoside and genkwanol A were the main constituents of Da-Ea. Collectively, the results suggested that Da-Ea displayed antiproliferative activities in Eca-109 cells by inducing apoptosis and S phase cell cycle arrest, as well as upregulating PPARγ expression levels.

Lycopene attenuates body weight gain through induction of browning via regulation of peroxisome proliferator-activated receptor γ in high-fat diet-induced obese mice

Lycopene (LYC), one of the major carotenoids in tomatoes, has been preclinically and clinically used to obesity and type 2 diabetes management. However, whether its ability of countering body weight gain is related to induction of brown-like adipocyte phenotype in white adipose tissues (WAT) remains largely unknown. Activation of peroxisome proliferator-activated receptor γ (PPARγ) serves the brown-like phenotype conversion and energy expenditure. Here, we show that LYC treatment promotes glucose consumption and improves insulin sensitivity, as well as fosters white adipocytes browning through up-regulating mRNA and protein expression levels of PPARγ, uncoupling protein 1, PPARγ coactivator-1α and PR domain-containing 16 in the differentiated 3T3-L1 adipocytes and primary adipocytes, as well as in the WAT of HFD-exposed obese mice. In addition, LYC treatment attenuates body weight gain and improves serum lipid profiles as well as promotes brown adipose tissue activation in obese mice. Moreover, PPARγ is induced with LYC intervention in mitochondria respiration and browning in white adipocytes and tissues. Taken together, these results suggest that LYC counteracts obesity and improves glucose and lipid metabolism through induction of the browning via up-regulation of PPARγ, which offers a new perspective of this compound to combat obesity and obesity-related disorders.

Methylxanthine Derivative-Rich Cacao Extract Suppresses Differentiation of Adipocytes through Downregulation of PPARγ and C/EBPs

Cacao extract (CE) consumption has beneficial effects on human health, such as lowering the risk of obesity. However, the underlying molecular mechanism for the anti-obesity effect of CE remains incompletely understood. Here, we used a 50% aqueous alcohol extract of cacao mass, which is rich in methylxanthine derivatives (about 11%) and poor in flavan-3-ols (less than 1%), and assessed the suppression effects of this extract on adipocyte differentiation to investigate the anti-obesity mechanism. CE dose-dependently decreased fat accumulation in 3T3-L1 cells without affecting cell viability. CE also dose-dependently decreased the protein and gene expression levels of two adipogenesis-related transcription factors, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding proteins (C/EBPs). Moreover, CE decreased protein expression levels of sterol regulatory element-binding protein 1 (SREBP1) and its downstream fatty acid synthase (FAS), which was accompanied by the retained localization of SREBP1 in the cytoplasm of 3T3-L1 cells. After ICR mice were fed a diet containing 1% CE for 1 wk, their white adipose tissue weight was lower, whereas their brown adipose tissue weight was higher compared with those of control animals. Additionally, the protein expression levels of PPARγ, C/EBPs, SREBP1, and FAS in the white adipose tissue of these mice were also lower than those in control animals. In contrast, diet supplementation with CE induced higher levels of phosphorylated AMP-activated protein kinase (AMPK) and its downstream acetyl-CoA carboxylase. In conclusion, methylxanthine derivative-rich CE decreases fat accumulation in adipocytes by downregulating the expression of the adipocyte differentiation master regulators through the activation of AMPK.

Short-term disuse promotes fatty acid infiltration into skeletal muscle.

BackgroundMany physiological and/or pathological conditions lead to muscle deconditioning, a well‐described phenomenon characterized by a loss of strength and muscle power mainly due to the loss of muscle mass. Fatty infiltrations, or intermuscular adipose tissue (IMAT), are currently well‐recognized components of muscle deconditioning. Despite the fact that IMAT is present in healthy human skeletal muscle, its increase and accumulation are linked to muscle dysfunction. Although IMAT development has been largely attributable to inactivity, the precise mechanisms of its establishment are still poorly understood. Because the sedentary lifestyle that accompanies age‐related sarcopenia may favour IMAT development, deciphering the early processes of muscle disuse is of great importance before implementing strategies to limit IMAT deposition.MethodsIn our study, we took advantage of the dry immersion (DI) model of severe muscle inactivity to induce rapid muscle deconditioning during a short period. During the DI, healthy adult men (n = 12; age: 32 ± 5) remained strictly immersed, in a supine position, in a controlled thermo‐neutral water bath. Skeletal muscle biopsies were obtained from the vastus lateralis before and after 3 days of DI.ResultsWe showed that DI for only 3 days was able to decrease myofiber cross‐sectional areas (−10.6%). Moreover, protein expression levels of two key markers commonly used to assess IMAT, perilipin, and fatty acid binding protein 4, were upregulated. We also observed an increase in the C/EBPα and PPARγ protein expression levels, indicating an increase in late adipogenic processes leading to IMAT development. While many stem cells in the muscle environment can adopt the capacity to differentiate into adipocytes, fibro‐adipogenic progenitors (FAPs) represent the population that appears to play a major role in IMAT development. In our study, we showed an increase in the protein expression of PDGFRα, the specific cell surface marker of FAPs, in response to 3 days of DI. It is well recognized that an unfavourable muscle environment drives FAPs to ectopic adiposity and/or fibrosis.ConclusionsThis study is the first to emphasize that during a short period of severe inactivity, muscle deconditioning is associated with IMAT development. Our study also reveals that FAPs could be the main resident muscle stem cell population implicated in ectopic adiposity development in human skeletal muscle.