Rosiglitazone Research Articles

Effect of Cistanche Tubulosa Extracts on Male Reproductive Function in Streptozotocin⁻Nicotinamide-Induced Diabetic Rats.

Diabetes is a chronic disorder characterized by hyperglycemia due to decreased levels of insulin or the inefficiency of the tissue to use it effectively. Infertility is known as a major outcome of diabetes and affects the male reproductive system by causing sperm impairment and gonadal dysfunction. Cistanche tubulosa is a parasitic plant which has the capacity to improve memory, immunity, and sexual ability, reduce impotence, and minimize constipation. This study was focused on the investigation of the anti-inflammatory and protective effects of echinacoside (ECH) in Cistanche tubulosa extract (CTE) on the male reproductive system of the diabetic rats. The antioxidant, anti-inflammatory, and protective effects of CTE were evaluated by both in vitro and in vivo methods. The in vitro results show that the ECH inhibited reactive oxygen species (ROS) production and improved StAR, CYP11A1, CYP17A1, and HSD17β3 protein expression. The in vivo analysis was carried out with three doses of echinacoside (ECH) (80, 160, and 320 mg/kg) in CTE. In total, 0.571 mg/kg of rosiglitazone (RSG) was administered as a positive control. Diabetes was induced by streptozotocin (STZ) (65 mg/kg) and nicotinamide (230 mg/kg) in combination with a high-fat diet (45%). The in vivo studies confirmed that the ECH improved blood sugar levels, insulin resistance, leptin resistance, and lipid peroxidation. It can restore kisspeptin 1 (KiSS1), G protein-coupled receptor GPR 54, suppressor of cytokine signaling 3 (SOCS-3), and sirtuin 1 (SIRT1) messenger ribonucleic acid (mRNA) expression in the hypothalamus and recover sex hormone level. Thus, this study confirmed the antioxidant, anti-inflammatory, and steroidogenesis effects of CTE.

Rosiglitazone ameliorates palmitic acid-induced cytotoxicity in TM4 Sertoli cells

The Sertoli cell is the only somatic cell within the seminiferous tubules, and is vital for testis development and spermatogenesis. Rosiglitazone (RSG) is a member of the thiazolidinedione family and is a peroxisome proliferator-activated receptor-γ (PPARγ) agonist. It has been reported that RSG protects various types of cells from fatty acid-induced damage. However, whether RSG serves a protective role in Sertoli cells against palmitic acid (PA)-induced toxicity remains to be elucidated. Therefore, the aim of the present study was to investigate the effect of RSG on PA-induced cytotoxicity in Sertoli cells. MTT assay and Oil Red O staining revealed that RSG ameliorated the PA-induced decrease in TM4 cell viability, which was accompanied by an alleviation of PA-induced lipid accumulation in cells. In primary mouse Sertoli cells, RSG also showed similar protective effects against PA-induced lipotoxicity. Knockdown of PPARγ verified that RSG exerted its protective role in TM4 cells through a PPARγ-dependent pathway. To evaluate the mechanism underlying the protective role of RSG on PA-induced lipotoxicity, the present study analyzed the effects of RSG on PA uptake, and the expression of genes associated with both fatty acid oxidation and triglyceride synthesis. The results demonstrated that although RSG did not affect the endocytosis of PA, it significantly elevated the expression of carnitine palmitoyltransferase (CPT)-1A, a key enzyme involved in fatty acid oxidation, which indicated that the protective effect of RSG may have an important role in fatty acid oxidation. On the other hand, the expression of CPT1B was not affected by RSG. Moreover, the expression levels of diacylglycerol O-acyltransferase (DGAT)-1 and DGAT2, both of which encode enzymes catalyzing the synthesis of triglycerides, were not suppressed by RSG. The results indicated that RSG reduced PA-induced lipid accumulation by promoting fatty acid oxidation mediated by CPT1A. The effect of RSG in protecting cells from lipotoxicity was also found to be specific to Sertoli cells and hepatocytes, and not to other cell types that do not store excess lipid in large quantities, such as human umbilical vein endothelial cells. These findings provide insights into the cytoprotective effects of RSG on Sertoli cells and suggest that PPARγ activation may be a useful therapeutic method for the treatment of Sertoli cell dysfunction caused by dyslipidemia.

PLA-PEG Nanoparticles Improve the Anti-Inflammatory Effect of Rosiglitazone on Macrophages by Enhancing Drug Uptake Compared to Free Rosiglitazone.

Among cardiovascular diseases, atherosclerosis remains the first cause of death in the United States of America and Europe, as it leads to myocardial infarction or stroke. The high prevalence of heart diseases is due to the difficulty in diagnosing atherosclerosis, since it can develop for decades before symptoms occur, and to the complexity of the treatment since targets are also important components of the host defenses. The antidiabetics thiazolidinediones, among which is rosiglitazone (RSG), have demonstrated anti-atherosclerotic effect in animal models, and are therefore promising candidates for the improvement of atherosclerosis management. Nevertheless, their administration is hindered by the insurgence of severe side effects. To overcome this limitation, rosiglitazone has been encapsulated into polymeric nanoparticles, which permit efficient delivery to its nuclear target, and selective delivery to the site of action, allowing the reduction of unwanted effects. In the present work, we describe nanoparticle formulation using polylactic acid (PLA) coupled to polyethylene glycol (PEG), their characterization, and their behavior on RAW264.7 macrophages, an important target in atherosclerosis treatment. RSG nanocarriers showed no toxicity on cells at all concentrations tested, an anti-inflammatory effect in a dose-dependent manner, up to 5 times more efficient than the free molecule, and an increased RSG uptake which is consistent with the effect shown. These biodegradable nanoparticles represent a valid tool to be further investigated for the treatment of atherosclerosis.

Protective effects of rosiglitazone on hepatic ischemia reperfusion injury in rats

To explore the protective effect of rosiglitazone (RGZ) on hepatic ischemia reperfusion injury (HIRI) and the underlying mechanisms. Methods: A rat model of ischemia-reperfusion injury was established by clamping the left and middle lobe of liver with noninvasive vascular clamp. A total of 30 Sprague-Dawley rats were randomly divided into a sham group, an HIRI group, and a RGZ group (10 rats in each group). Two hours after reperfusion, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, lactate dehydrogenase (LDH) level, malondialdehyde (MDA) content and catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were examined. HE staining was used to observe liver pathological morphology. The liver peroxisome proliferators-activated receptor γ (PPAR-γ), p-PPAR-γ, nuclear factor related factor 2 (Nrf-2), antioxidant response element (ARE), heme oxygenase 1 (HO-1) and quinone oxidoreductase-1 (NQO-1) were detected by Western blot. Results: Compared with the HIRI group, the levels of ALT, AST, LDH and MDA in the RGZ group were significantly decreased (all P<0.05), while the levels of Nrf-2, ARE, HO-1 and NQO-1 in the RGZ group were significantly increased. The hepatic swelling, necrosis and pathological damage were decreased (all P<0.05). In addition, there was no difference in the level of PPAR-γ between the 2 groups (P>0.05). Conclusion: PPAR-γ agonist RGZ can attenuate HIRI, which may be related to activating Nrf2/ARE signaling pathway and enhancement of antioxidant ability.

PPARγ agonist rosiglitazone alters the temporal and spatial distribution of inflammation during abdominal aortic aneurysm formation.

Research into inflammation during abdominal aortic aneurysm (AAA) formation remains inconclusive. The present study aimed to demonstrate the temporal and spatial distribution of inflammatory cytokines, and to confirm the effect of peroxisome proliferator‑activated receptor γ (PPARγ) on the incidence of AAA formation and the distribution of inflammation in the disease process. Male apolipoprotein E‑/‑ mice were randomly divided into eight groups: Angiotensin II (Ang‑II)‑only 7, 14, 21, 28 and 42days groups, Ang‑II with rosiglitazone (RGZ) 28 and 42days groups, and the saline control 42days group. The early stage was defined as between 7 and 21days, and the late stage as between 28 and 42days. Incidences of early rupture and late rupture, aneurysm formation and the maximum diameters of the aorta were recorded. Suprarenal abdominal aortic tissues were collected for histological analysis, and western blotting was performed to reveal the distribution of inflammation. Treatment with Ang‑II caused a significant dilation of the aorta in the late stage; however, this was not observed in the early stage. RGZ reduced the maximum diameters in the late stage. With the pathological process alterations, the inflammatory type shifted. Regarding temporal distribution, the tumor necrosis factor (TNF)‑α expression level was increased over time, and the interleukin (IL)‑10 expression level significantly decreased. When considering the spatial distribution, TNF‑α was expressed dominantly in the aneurysmal body and IL‑10 was dominant in the aneurysmal neck in the late stage. The PPARγ agonist RGZ may reduce the expression of TNF‑α in the late stage and increase the expression level of IL‑10, maintaining the TNF‑α or IL‑10 expression levels at the same levels as in the early stage. Aortic inflammation during AAA formation is dynamic. Protective anti‑inflammatory cytokines are upregulated in the early 'compensatory stage'; however, pro‑inflammatory cytokines are dominant in the late 'decompensatory stage'. PPARγ is likely to continue to upregulate the expression of anti‑inflammatory cytokines, extend the 'compensatory stage', and decelerate the process of AAA development and rupture.

Ameliorative effects of indomethacin at different concentrations on endothelial insulin resistance through two distinct pathways

Indomethacin (IDMT), a non-selective inhibitor of cycloxygenase-2 (COX-2), plays important roles in anti-inflammation and analgesia and it is commonly used to treat the patients with rheumatic and rheumatoid arthritis. Besides, various literatures reported that IDMT is a synthetic ligand of peroxisome proliferator activated receptor gamma (PPARγ). Rosiglitazone (RSG), an insulin-sensitizer, is also a synthetic ligand and applied clinically to cure the patients with type 2 diabetes mellitus. However, up to date little is known about whether IDMT ameliorates endothelial insulin resistance (IR). Accordingly, the purpose of this study is to investigate the effects of IDMT on endothelial IR and its underlying mechanism. Our present results showed that IDMT improved the endothelial IR induced by high glucose and fat concentration (HG/HF) in a concentration and time-dependent manner. Intriguingly, we further identified that 0.25 mM of IDMT noticeably induced the expression levels of PPARγ, AKT and endothelial nitric oxide synthase (eNOS) but failed to notably reverse the increases in expression levels of COX-2, inhibitory κB kinase (IKK) and tumor necrosis factor alpha (TNFα) induced by HG/HF; whereas 1.0 mM of IDMT exerted opposite effects compared with 0.25 mM of IDMT. Therefore, we conclude that IDMT ameliorates the endothelial IR induced by HG/HF through two distinct pathways, i.e., a lower concentration of IDMT through a PPARγ-AKT-eNOS pathway while a higher concentration mainly via an IKK-COX-2/TNFα pathway. The findings might provide a novel clinical use for IDMT to cure IR-related disorders.

PPAR GAMMA STIMULATION BY ROSIGLITAZONE DECREASES BLOOD PRESSURE AND RENAL APOPTOSIS IN A RAT HYPERTENSION MODEL SECONDARY TO AORTIC COARCTATION

Objective: Rosiglitazone (RGZ), a peroxisome proliferator-activated receptor gamma (PPARγ) ligand, has been reported to function like an insulin sensitizer and exerts cardiovascular actions. The activation of PPARγ has been described to have antiapoptotic effects in renal ischemia-reperfusion models. We hypothesized that RGZ exerts a PPARγ–dependent regulation of blood pressure and decreases kidney apoptosis in an experimental model of hypertension. Design and method: We performed the experiments in normotensive (sham) and aortic coarctation (AoCo)-induced hypertensive male Wistar rats. Both sham- and AoCo rats were treated for 7 days with vehicle (V), RGZ (5 mg/kg/day) or RGZ plus BADGE (120 mg/kg/day). After treatment, we measured blood pressure and vascular reactivity on aortic rings as well as the expression and activity of renin-angiotensin system (RAS) components. To study the effect on renal apoptosis, we isolated the kidneys, separated both, cortex and medulla, and evaluated the expression of apoptotic (Bax) and anti-apoptotic proteins (14-3-3ε, p-Akt and Bcl2) in both regions. Results: RGZ in AoCo group decreased blood pressure values and improved vascular response to ACh in a PPAR dependent manner. RGZ lowered serum AngII- but increased Ang-(1–7) levels. Also, RGZ decreased oxidative stress markers and improved antioxidant capacity. Regarding protein expression of ACE and AT1, it was lower in RGZ- than in vehicle-treated rats but the expression of ACE2, MAS, and AT2 receptors was increased. Regarding renal apoptosis, in the cortex from AoCo-ischemic kidney Bax was increased, while 14-3-3ε and PPARγ proteins were decreased. Treatement with RGZ, prevented PPARγ and 14-3-3ε lower expression, however, it had no effect on Bax expression. With respect Bcl-2 expression was slightly increased in RGZ-treated group. These effects were not observed in medulla were proteins evaluated presented no differences in expression in all four groups. Conclusions: We conclude that RGZ lowers blood pressure values by reducing the expression of ACE, decreasing the levels of AngII, and increasing levels of Ang-(1–7) in a PPARγ-dependent manner. RGZ decreases apoptosis in renal cortex and medulla in hypertensive rats. The increase of PPARγ, Bcl-2 and 14-3-3ε observed in renal cortex could contribute to this effect.

Rosiglitazone

Rosiglitazone

Retinoid X Receptor Activation During Adipogenesis of Female Mesenchymal Stem Cells Programs a Dysfunctional Adipocyte.

Early life exposure to endocrine-disrupting chemicals (EDCs) is an emerging risk factor for the development of obesity and diabetes later in life. We previously showed that prenatal exposure to the EDC tributyltin (TBT) results in increased adiposity in the offspring. These effects linger into adulthood and are propagated through successive generations. TBT activates two nuclear receptors, the peroxisome proliferator-activated receptor (PPAR) γ and its heterodimeric partner retinoid X receptor (RXR), that promote adipogenesis in vivo and in vitro. We recently employed a mesenchymal stem cell (MSC) model to show that TBT promotes adipose lineage commitment by activating RXR, not PPARγ. This led us to consider the functional consequences of PPARγ vs RXR activation in developing adipocytes. We used a transcriptomal approach to characterize genome-wide differences in MSCs differentiated with the PPARγ agonist rosiglitazone (ROSI) or TBT. Pathway analysis suggested functional deficits in TBT-treated cells. We then compared adipocytes differentiated with ROSI, TBT, or a pure RXR agonist IRX4204 (4204). Our data show that RXR activators ("rexinoids," 4204 and TBT) attenuate glucose uptake, blunt expression of the antidiabetic hormone adiponectin, and fail to downregulate proinflammatory and profibrotic transcripts, as does ROSI. Finally, 4204 and TBT treatment results in an inability to induce markers of adipocyte browning, in part due to sustained interferon signaling. Taken together, these data implicate rexinoids in the development of dysfunctional white adipose tissue that could potentially exacerbate obesity and/or diabetes risk in vivo. These data warrant further screening and characterization of EDCs that activate RXR.

Antidepressant and anxiolytic like effects of Urtica dioica leaves in streptozotocin induced diabetic mice.

The present study wasaimed to investigate the effect of Urtica dioica Linn. (UD) extract against chronic diabetes mediated anxiogenic and depressive like behavior in mice. Streptozotocin (STZ) (50mg/kg, i.p.) for 5 consecutive days was used to induce diabetes followed by treatment with UD leaves extract (50mg/kg, p.o.) and rosiglitazone (ROSI) (5mg/kg, p.o.) for 8weeks. STZ induced chronic diabetes significantly induced anxiety and depressive like behavior in mice. Chronic diabetes significantly downregulated BDNF (p < 0.001), TrKB (p < 0.001), Cyclin D1 (p < 0.001), Bcl2 (p < 0.05) and autophagy7 (p < 0.001), while upregulated iNOS (p < 0.05) mRNA expression in the hippocampus as compared to control mice. In addition, chronic diabetes significantly increased the expression of TNF-α in CA1 (p < 0.001), CA2 (p < 0.01), CA3 (p < 0.001) and DG (p < 0.001) regions of hippocampus as compared to control mice. Chronic diabetes mediated neuronal damage in the CA2, CA3 and DG regions of hippocampus. Chronic administration of UD leaves extract significantly reversed diabetes mediated anxiogenic and depressive like behavior in mice. Further, UD treatment significantly upregulated BDNF (p < 0.01), TrKB (p < 0.001), Cyclin D1 (p < 0.001), Bcl2 (p < 0.01), autophagy5 (p < 0.01) and autophagy7 (p < 0.001), while downregulated iNOS (p < 0.05) mRNA expression in the hippocampus of diabetic mice. Concomitantly, UD administration significantly decreased the expression of TNF-α in hippocampal CA1 (p < 0.001), CA2 (p < 0.01), CA3 (p < 0.001) and DG (p < 0.001) regions of diabetic mice. Diabetes mediated neuronal damage and DNA fragmentation in the hippocampus was substantially attenuated following UD treatment. UD leaves extract might prove to be effective for diabetes mediated anxiety and depressive like behavior.

Insulin-Sensitizing Effect of Peroxisome Proliferator Activated Receptor Gamma Agonist on Serum Visfatin Levels in High Fat Diet Induced Type 2 Diabetes Mellitus

The aim of the study was to find the correlation between serum visfatin, glucose and insulin homeostasis in high fat diet (HFD) induced type 2 diabetes mellitus (T2DM). The study also focuses on the insulin sensitizing effects of peroxisomes proliferator-activated receptor gamma activation via agonist (rosiglitazone) in the regulation of serum visfatin levels. The study was performed in Wistar rats (180–220 g), categorized into five groups. Group 1: Control animals remain fed on a normal rat diet, Group 2: HFD-fed group, Group 3: HFD treated group, treated with rosiglitazone (RSG) for 7 days, Group 4: T2DM group and Group 5: T2DM treated group, treated with rosiglitazone for 7 days. The experimental model of T2DM was developed by feeding rats with HFD for 8 weeks and a low dose of streptozotocin (i.p. 35 mg/ml/kg body weight). Anthropometric parameters, blood glucose, serum visfatin and insulin level, insulin sensitivity and insulin resistance (HOMA-IR, HOMA-β and QUICKI) were estimated. The correlation between visfatin levels and insulin resistance in all groups were also investigated. Hyperglycaemia in HFD-induced T2DM elevated the serum insulin and visfatin levels. Increased insulin resistance was also observed in HFD fed and T2DM rats. Administration of rosiglitazone significantly decreases the insulin resistance by increasing the insulin sensitivity and decreased serum visfatin in HFD and T2DM rats. In conclusion increased serum visfatin levels in HFD and T2DM are a probable early diagnostic biomarker for diabetic complications. That could be reversed by insulin sensitization to improve endothelial function in T2DM patients in future.

Indomethacin Induces Browning and Brown Adipogenesis in Murine 3T3‐L1 White Adipocytes and Human Brown Fat Cells

Functional brown adipose tissue, including classical brown adipocytes and brown‐like or beige adipocytes, which develop within white adipose tissue in response to various stimuli, have emerged as novel targets for obesity treatment and prevention. Identifying strategies that increase UCP‐1 expression and induce browning and brown adipogenesis is key to unlocking thermogenic potential. Indomethacin (INDO) is a non‐selective Cox‐1/Cox‐2 inhibitor which is an approved NSAID used to treat and relief inflammatory diseases. It has been reported that INDO induced C3H10T1/2 mesenchymal stem cell differentiation into adipocytes by activating PPARg, which is also important for browning and brown adipogenesis. In this study, INDO was tested at various doses (2, 5, 10, 20, 50 mM) in 3T3‐L1 mouse pre‐adipocytes in a 7‐day differentiation process as well as human brown fat cells in a 21‐day differentiation process. Rosiglitazone (ROSI), a well‐known browning agent and PPARg agonist, was used as a positive control. At the end of differentiation, 3T3‐L1 cells were subjected to thermogenic activation by isoproterenol (ISO), a b‐adrenergic receptor agonist, or the control for 6–24 hours. Protein and mRNA expression of UCP‐1, PPARg, and PGC1a were measured. mRNA analysis of other brown and beige maker genes (PRDM16, Cidea, and CD137), and white marker genes (IGFBP3), as well as mitochondrial related genes (Nrf and Cox4a) were also measured. For mechanistic exploration, PPARg transactivation reporter gene assays were conducted. In addition, an adenovirus mediated PPARg knock down (KD) in 3T3‐L1 cells was generated. We report that similar to ROSI, INDO significantly induced UCP‐1 mRNA expression in 3T3‐L1 cells under basal and ISO stimulated condition compared to the controls (p&lt;0.05 for INDO at 10, 20, 50 μM under basal condition and INDO at 2, 5, 10, 20 μM under ISO stimulated condition). INDO also significantly induced mRNA expression of Nrf and PGC1a (p&lt;0.05). INDO also significantly induced UCP1 and PGC1α protein expression under basal condition (p&lt;0.05 INDO at 10 and 20 μM) while suppressing PPARg protein expression (p&lt;0.05 INDO at 10 and 20 μM). Mechanistically, INDO significantly activated PPARg in 3T3‐L1 cells (p&lt;0.01 for INDO at 20 and 50 μM), which is consistent with the previous report in C3H10T1/2 cells. Moreover, upregulation of UCP1 and other brown markers by INDO were decreased in PPARg KD cells compared to non‐targeting adenovirus infected control cells. Furthermore, we explored INDO's effects on promoting brown adipogenesis in human brown fat cells. We report that INDO significantly induced PPARg, PGC1α, and DIO2 at 20 μM (p&lt;0.05). INDO also significantly induced UCP1 mRNA and protein expression (p&lt;0.01 for INDO at 20 μM for mRNA and p&lt;0.05 for INDO at 2, 5, 10 μM, for protein). Taken together, despite INDO's potential systemic side‐effects, our results reveal a novel capacity for INDO to induce browning and brown adipogenesis through acting as a PPARg agonist.Support or Funding InformationThe work has been partially supported by NIH 1R15AT008733 award.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

PPARγ alleviated hepatocyte steatosis through reducing SOCS3 by inhibiting JAK2/STAT3 pathway

Peroxisome proliferator-activated receptor gamma (PPARγ) participates in the process of insulin resistance (IR), a crucial pathophysiology in non-alcoholic fatty liver disease (NAFLD). Meanwhile, suppressor of cytokine signaling3 (SOCS3) also regulates IR in NAFLD. Both PPARγ and SOCS3 play a role in NAFLD through regulating IR, while it is unclear whether these two proteins interact to regulate hepatic steatosis. PPARγ, SOCS3 and its associated JAK2/STAT3 pathway were analyzed using Kuppfer cells (KCs) treatment with LPS and BRL-3A cells treatment with palmitic acid, KC-conditioned medium (KCCM), PPARγ agonist rosiglitazone (ROZ) or JAK2 inhibitor AG490 to demonstrate the role of PPARγ and SOCS3 in hepatocytes steatosis. As LPS concentration increasing, phagocytosis activity of KCs decreased; but releasing of TNF-α and IL-6 increased. After treatment with KCCM, mRNA level of SOCS3, JAK2 and STAT3 as well as protein expression of SOCS3, p-JAK2 and p-STAT3 in steatosis BRL-3A cells increased significantly, which were inhibited by AG490 or ROZ treatment. Taken together, these results indicated that KCCM attributed to KCs dysfunction facilitated hepatocyte steatosis through promoting expressing SOCS3; but PPARγ agonist ROZ alleviated steatosis through reducing SOCS3 expression by inhibiting JAK2/STAT3 in hepatocytes.

9- and 13-HODE regulate fatty acid binding protein-4 in human macrophages, but does not involve HODE/GPR132 axis in PPAR-γ regulation of FABP4.

Both activation of monocytes and increased serum fatty acid binding protein-4 (FABP4) occur in diabetes and are associated with increased atherosclerosis. The oxidized lipid, 9-hydroxyoctadecadienoic acid (9-HODE) increases FABP4 in macrophages, and is a ligand for G protein-coupled receptor 132 (GPR132). We investigated the involvement of GPR132 in mediating the 9-, 13-HODE stimulation of FABP4 secretion, and whether GPR132 expression is increased in monocytes from patients with type 2 diabetes. The effects of siRNA silencing of GPR132 gene and of the PPAR-γ antagonist T0070907 were studied in THP-1 cells. Serum levels of FABP4 and other adipokines were measured in patients with diabetes, and monocyte subpopulations were analyzed using flow cytometry. GPR132 mRNA was quantified in isolated CD14+ cells. 9-HODE and 13-HODE increased FABP4 expression in THP-1 monocytes and macrophages, and also increased GPR132 expression. Silencing of GPR132 did not influence the increase in FABP4 with 9-HODE, 13-HODE, or rosiglitazone (ROSI). By contrast, T0070907 inhibited the effect of all three ligands on FABP4 expression. Diabetic subjects had increased serum FABP4, and activated monocytes. They also expressed higher levels of GPR132 mRNA in CD14+ cells. We conclude that GPR132 is an independent monocyte activation marker in diabetes, but does not contribute to PPAR-γ-mediated induction of FABP4 by HODEs.

Effects of 5-aminoimidazole-4-carboxamide ribonucleotide on the palmitic acid-induced expression of mitochondrial function-related proteins in C2 C12 skeletal muscle cells

Objective To investigate the effects of activated protein kinase(AMPK)agonists on the expression of peroxisome proliferator-activated receptor γ coactivator 1α(PGC1α), mitofusin 2(Mfn2)and nuclear respiratory factor1(NRF1)in the process of lipid-induced mitochondrial dysfunction of skeletal muscles. Methods The expression of PGC1α, Mfn2 and NRF1 in C2C12 skeletal muscle cells after intervention with palmitic acid was detected using reverse transcription-polymerase chain reaction(RT-PCR)and Western blotting.The effect of 5-aminoimidazole-4-carboxamide ribonucleotide(AICAR)on Mfn2 and NRF1 and, the expression of Mfn2 and NRF1 in C2C12 cells induced by a PGC1α activator and PGC1α-siRNA were assessed by Western blotting. Results Palmitic acid decreased the mRNA and protein expression of PGC1α, Mfn2 and NRF1 in C2C12 cells(P<0.05). Additionally, AICAR, rosiglitazone and metformin up-regulated PGC1α expression, regardless of the presence of palmitic acid and, AICAR reversed lipid-induced PGC1α, Mfn2 and NRF1 attenuation in C2C12 cells.Furthermore, Mfn2 and NRF1 protein expression increased with PGC1α over-expression, and decreased with down-regulated PGC1α expression. Conclusions AICAR can relieve the adverse effects of palmitic acid on PGC1α, Mfn2 and NRF1 in skeletal muscle cells.Moreover, it appears that AICAR can up-regulate Mfn2 and NRF1 expression through activating PGC1α. Key words: Adenylate kinase; Mitochondria; Muscle, skeletal

Rosiglitazone diminishes the high-glucose-induced modulation of 5-fluorouracil cytotoxicity in colorectal cancer cells.

Colorectal cancer (CRC) is the third most leading cause of morbidity and mortality throughout the world. 5-fluorouracil (5-FU), which is often administrated to disrupt carcinogenesis, was found to elevate blood glucose level among CRC patients. Thus, this study was conducted to evaluate the influence of rosiglitazone on antiproliferative effect of 5-FU using cellular model. Two human colonic carcinoma cell lines (HCT 116 and HT 29) were cultured in the presence of 5-FU, rosiglitazone or in combination under normal and high glucose concentration. The drug cytotoxicity was evaluated using the MTT assay whereas the assessment of cell cycle was carried out using the flow cytometry technique. Combination index (CI) method was used to determine the drug interaction between rosiglitazone and 5-FU. High glucose diminished the cytotoxic effect of 5-FU but at a high drug dosage, this effect could be overcome. Cell cycle analysis demonstrated that 5-FU and rosiglitazone caused G1-phase arrest and S-phase arrest, respectively. CI values indicated that rosiglitazone exerted synergistic effect on 5-FU regardless of glucose levels. This study is the first to demonstrate the influence of rosiglitazone on cytotoxicity of 5-FU under normal or high glucose level. Rosiglitazone may be a promising drug for enhancing the efficacy of 5-FU in the treatment of CRC associated with hyperglycemia.

Benefits of VCE-003.2, a cannabigerol quinone derivative, against inflammation-driven neuronal deterioration in experimental Parkinson\u2019s disease: possible involvement of different binding sites at the PPAR\u03b3 receptor

BackgroundNeuroprotection with cannabinoids in Parkinson’s disease (PD) has been afforded predominantly with antioxidant or anti-inflammatory cannabinoids. In the present study, we investigated the anti-inflammatory and neuroprotective properties of VCE-003.2, a quinone derivative of the non-psychotrophic phytocannabinoid cannabigerol (CBG), which may derive its activity at the peroxisome proliferator-activated receptor-γ (PPARγ). The compound is also an antioxidant.MethodsWe evaluated VCE-003.2 in an in vivo [mice subjected to unilateral intrastriatal injections of lipopolysaccharide (LPS)] model of PD, as well as in in vitro (LPS-exposed BV2 cells and M-213 cells treated with conditioned media generated from LPS-exposed BV2 cells) cellular models. The type of interaction of VCE-003.2 at the PPARγ receptor was furtherly investigated in bone marrow-derived human mesenchymal stem cells (MSCs) and sustained with transcriptional assays and in silico docking studies.ResultsVCE-003.2 has no activity at the cannabinoid receptors, a fact that we confirmed in this study using competition studies. The administration of VCE-003.2 to LPS-lesioned mice attenuated the loss of tyrosine hydroxylase (TH)-containing nigrostriatal neurons and, in particular, the intense microgliosis provoked by LPS in the substantia nigra, measured by Iba-1/Cd68 immunostaining. The analysis by qPCR of proinflammatory mediators such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and inducible nitric oxide synthase (iNOS) in the striatum showed they were markedly elevated by the LPS lesion and strongly reduced by the treatment with VCE-003.2. The effects of VCE-003.2 in LPS-lesioned mice implied the activation of PPARγ receptors, as they were attenuated when VCE-003.2 was co-administered with the PPARγ inhibitor T0070907. We then moved to some in vitro approaches, first to confirm the anti-inflammatory profile of VCE-003.2 in cultured BV2 cells exposed to LPS. VCE-003.2 was able to attenuate the synthesis and release of TNF-α and IL-1β, as well as the induction of iNOS and cyclooxygenase-2 (COX-2) elicited by LPS in these cells. However, we found such effects were not reversed by GW9662, another classic PPARγ antagonist. Next, we investigated the neuroprotective effects of VCE-003.2 in cultured M-213 neuronal cells exposed to conditioned media generated from LPS-exposed cultured BV2 cells. VCE-003.2 reduced M-213 cell death, but again, such effects were not reversed by T0070907. Using docking analysis, we detected that VCE-003.2 binds both the canonical and the alternative binding sites in the PPARγ ligand-binding pocket (LBP). Functional assays further showed that T0070907 almost abolished PPARγ transcriptional activity induced by rosiglitazone (RGZ), but it did not affect the activity of VCE-003.2 in a Gal4-Luc system. However, T0070907 inhibited the effects of RGZ and VCE-003.2 on the expression of PPARγ-dependent genes upregulated in MSCs.ConclusionsWe have demonstrated that VCE-003.2 is neuroprotective against inflammation-driven neuronal damage in an in vivo model of PD and in in vitro cellular models of neuroinflammation. Such effects might involve PPARγ receptors, although in silico and in vitro experiments strongly suggest that VCE-003.2 targets PPARγ by acting through two binding sites at the LBP, one that is sensitive to T0070907 (canonical binding site) and other that is not affected by this PPARγ antagonist (alternative binding site).

Insulin degrading enzyme contributes to the pathology in a mixed model of Type 2 diabetes and Alzheimer’s disease: possible mechanisms of IDE in T2D and AD

Insulin degrading enzyme (IDE) is believed to act as a junction point of Type 2 diabetes (T2D) and Alzheimer's disease (AD); however, the underlying mechanism was not completely clear yet. Transgenic APPSwe/PS1 mice were used as the AD model and were treated with streptozocin/streptozotocin (STZ) to develop a mixed mice model presenting both AD and T2D. Morris Water Maze (MWM) and recognition task were performed to trace the cognitive function. The detection of fasting plasma glucose (FPG) and plasma insulin concentration, and oral glucose tolerance test (OGTT) were used to trace the metabolism evolution. Aβ40 and Aβ42 were quantified by colorimetric ELISA kits. The mRNA or protein expression levels were determined by quantitative real-time RT-PCR and Western blotting analysis respectively. T2D contributes to the AD progress by accelerating and worsening spatial learning and recognition impairments. Metabolic parameters and glucose tolerance were significantly changed in the presence of the AD and T2D. The expression levels of IDE, PPARγ, and AMPK were down-regulated in mice with AD and T2D. PPARγ activator rosiglitazone (RSZ) or AMPK activator AICAR increased the expression level of IDE and decreased Aβ levels in mice with AD and T2D. RSZ or AICAR treatment also alleviated the spatial learning and recognition impairments in AD and T2D mice. Our results found that, in the mice with T2D and AD, the activators of PPARγ/AMPK signaling pathway significantly increased the expression level of IDE, and decreased the accumulation of Aβ40 and Aβ42, as well as alleviated the spatial learning and recognition impairments.

Rosiglitazone as a Modulator of TLR4 and TLR3 Signaling Pathways in Rat Primary Neurons and Astrocytes.

An antidiabetic drug of the thiazolidinedione class, rosiglitazone (RG) demonstrates anti-inflammatory properties in various brain pathologies. The mechanism of RG action in brain cells is not fully known. To unravel mechanisms of RG modulation of toll-like receptor (TLR) signaling pathways, we compare primary rat neuron and astrocyte cultures stimulated with the TLR4 agonist lipopolysaccharide (LPS) and the TLR3 agonist poly I:C (PIC). Both TLR agonists induced tumor necrosis factor (TNFα) release in astrocytes, but not in neurons. Neurons and astrocytes released interleukin-10 (IL-10) and prostaglandin E2 (PGE2) in response to LPS and PIC. RG decreased TLR-stimulated TNFα release in astrocytes as well as potentiated IL-10 and PGE2 release in both astrocytes and neurons. RG induced phosphorylation of p38 and JNK MAPK (mitogen-activated protein kinase) in neurons. The results reveal new role of RG as a modulator of resolution of neuroinflammation.

Determination of the illegal adulteration of natural healthcare products with chemical drugs using surface-enhanced Raman scattering.

The illegal adulteration of natural healthcare products with chemical drugs can result in serious health risks for consumers. Thus there is an urgent need for a fast and precise detection method. In this research, sodium alginate (SA)-silver nanoparticles (AgNPs) were used as a substrate in surface-enhanced Raman scattering (SERS) for determining vardenafil and rosiglitazone maleate (ROS). Sodium alginate can not only reduce silver ions rapidly to AgNPs as reducing agents but can also protect AgNPs from aggregation by its use as a capping agent. The coffee ring effect has also been applied in this research to facilitate the separation and concentration of analytes. A prominent SERS enhancement can be obtained on the ring because of the electromagnetic mechanism. Both of the properties, including the use of SA and the coffee ring effect, make the method more sensitive in detecting the analytes compared to the classical AgNPs, SERS substrate which were produced using the reduction of silver nitrate with sodium citrate. The method displays a linear response for the determination of vardenafil and ROS in the 4.88-488 μg·mL-1 and 4.74-94.7 μg·mL-1 concentration ranges, and the limit of detection is as low as 1.63 μg·mL-1 and 2.20 μg·mL-1, respectively. The method was successfully applied to the detection of vardenafil and ROS in healthcare products, with recoveries between 91.52% to 107.1% and relative standard deviations of less than 4.31%. This method shows good potential for real applications.