- Time-dependent effect of phytocannabinoid treatments in fat cells. [Journal Article]
- PRPhytother Res 2018 Feb 21
- The objectives of this paper is to investigate, demonstrate, and compare the mechanism of action of phytocannabinoids as antidiabetic and anti-obesity agents in preadipocytes and adipocytes, relative...
The objectives of this paper is to investigate, demonstrate, and compare the mechanism of action of phytocannabinoids as antidiabetic and anti-obesity agents in preadipocytes and adipocytes, relative to rosiglitazone and metformin. Briefly, cannabis extract, Δ9-tetrahydrocannabinol and cannabidiol (in very low dosages) were shown to promote glucose uptake higher or to equivalent levels, reduce fat accumulation, and reverse the insulin-resistant state of 3T3-L1 cells more effectively, relative to rosiglitazone and metformin. The phytocannabinoids had a more pronounced effect in preadipocytes undifferentiated model rather than the differentiated model. They induced a protective effect at the mitochondrial level by preventing overactivity of the succinate dehydrogenase pathway (p < .01), unlike rosiglitazone, through activation of the glycerol-3-phosphate dehydrogenase shuttling system. An increase in oxygen consumption and an increased expression of beta to alpha adrenoceptors (p < .05) in treated cells were noted. These findings contribute toward understanding the mechanism of action of phytocannabinoids in fat cells and highlight the antidiabetic and anti-obesity properties of various phytocannabinoids that could potentially support the treatment of obesity-related insulin resistance.
- PPARs: Key Regulators of Airway Inflammation and Potential Therapeutic Targets in Asthma. [Journal Article]
- NRNucl Receptor Res 2018; 5
- Asthma affects approximately 300 million people worldwide, significantly impacting quality of life and healthcare costs. While current therapies are effective in controlling many patients' symptoms, ...
Asthma affects approximately 300 million people worldwide, significantly impacting quality of life and healthcare costs. While current therapies are effective in controlling many patients' symptoms, a large number continue to experience exacerbations or treatment-related adverse effects. Alternative therapies are thus urgently needed. Accumulating evidence has shown that the peroxisome proliferator-activated receptor (PPAR) family of nuclear hormone receptors, comprising PPARα, PPARβ/δ, and PPARγ, is involved in asthma pathogenesis and that ligand-induced activation of these receptors suppresses asthma pathology. PPAR agonists exert their anti-inflammatory effects primarily by suppressing pro-inflammatory mediators and antagonizing the pro-inflammatory functions of various cell types relevant to asthma pathophysiology. Experimental findings strongly support the potential clinical benefits of PPAR agonists in the treatment of asthma. We review current literature, highlighting PPARs' key role in asthma pathogenesis and their agonists' therapeutic potential. With additional research and rigorous clinical studies, PPARs may become attractive therapeutic targets in this disease.
- Screening for PPAR Non-Agonist Ligands Followed by Characterization of a Hit, AM-879, with Additional No-Adipogenic and cdk5-Mediated Phosphorylation Inhibition Properties. [Journal Article]
- FEFront Endocrinol (Lausanne) 2018; 9:11
- Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of a nuclear receptor superfamily and acts as a ligand-dependent transcription factor, playing key roles in maintenance of adipose...
Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of a nuclear receptor superfamily and acts as a ligand-dependent transcription factor, playing key roles in maintenance of adipose tissue and in regulation of glucose and lipid homeostasis. This receptor is the target of thiazolidinediones, a class of antidiabetic drugs, which improve insulin sensitization and regulate glycemia in type 2 diabetes. Despite the beneficial effects of drugs, such as rosiglitazone and pioglitazone, their use is associated with several side effects, including weight gain, heart failure, and liver disease, since these drugs induce full activation of the receptor. By contrast, a promising activation-independent mechanism that involves the inhibition of cyclin-dependent kinase 5 (CDK5)-mediated PPARγ phosphorylation has been related to the insulin-sensitizing effects induced by these drugs. Thus, we aimed to identify novel PPARγ ligands that do not possess agonist properties by conducting a mini-trial with 80 compounds using the sequential steps of thermal shift assay, 8-anilino-1-naphthalenesulfonic acid fluorescence quenching, and a cell-based transactivation assay. We identified two non-agonist PPARγ ligands, AM-879 and P11, and one partial-agonist, R32. Using fluorescence anisotropy, we show that AM-879 does not dissociate the NCOR corepressorin vitro, and it has only a small effect on TRAP coactivator recruitment. In cells, AM-879 could not induce adipocyte differentiation or positively regulate the expression of genes associated with adipogenesis. In addition, AM-879 inhibited CDK5-mediated phosphorylation of PPARγin vitro. Taken together, these findings supported an interaction between AM-879 and PPARγ; this interaction was identified by the analysis of the crystal structure of the PPARγ:AM-879 complex and evidenced by AM-879's mechanism of action as a putative PPARγ non-agonist with antidiabetic properties. Moreover, we present an optimized assay pipeline capable of detecting ligands that physically bind to PPARγ but do not cause its activation as a new strategy to identify ligands for this nuclear receptor.
- Role of peroxisome proliferator-activated receptor-gamma activation on visfatin, advanced glycation end products, and renal oxidative stress in obesity-induced type 2 diabetes mellitus. [Journal Article]
- HEHum Exp Toxicol 2018 Jan 01; :960327118757588
- The present study focused on the role of peroxisome proliferator-activated receptor-gamma (PPAR-γ) activation on renal oxidative damages, serum visfatin, and advanced glycation end products (AGEs) in...
The present study focused on the role of peroxisome proliferator-activated receptor-gamma (PPAR-γ) activation on renal oxidative damages, serum visfatin, and advanced glycation end products (AGEs) in high-fat diet (HFD)-induced type 2 diabetes mellitus. Following the institutional animal ethics committee guidelines, Wistar rats were categorized into five groups: group 1: fed on a normal rat diet; group 2: HFD-induced obese rats (HFD for 8 weeks); group 3: HFD-fed rats treated with rosiglitazone (RSG; 3 mg/kg orally for 7 days); group 4: T2DM rats induced by HFD and low dose of streptozotocin (i.p. 35 mg/kg); group 5: T2DM rats treated with RSG (3 mg/kg orally for 7 days). Serum levels of AGEs and visfatin, renal damage, and oxidative stress were analyzed. Results showed that HFD-induced obesity and T2DM caused an elevated blood glucose, serum AGEs, visfatin, insulin, urea, creatinine, and tissue malondialdehyde, whereas a decreased catalase and superoxide dismutase activity were observed. The PPAR-γ activation via agonist restored these changes. Our findings suggest that AGEs and visfatin possess an important role in the progression of renal oxidative stress, which can be reduced by the PPAR-γ agonist that impede deleterious effects of HFD and HFD-induced T2DM on renal damage.
- GATA3, HDAC6, and BCL6 Regulate FOXP3+ Treg Plasticity and Determine Treg Conversion into Either Novel Antigen-Presenting Cell-Like Treg or Th1-Treg. [Journal Article]
- FIFront Immunol 2018; 9:45
- We conducted an experimental database analysis to determine the expression of 61 CD4+ Th subset regulators in human and murine tissues, cells, and in T-regulatory cells (Treg) in physiological and pa...
We conducted an experimental database analysis to determine the expression of 61 CD4+ Th subset regulators in human and murine tissues, cells, and in T-regulatory cells (Treg) in physiological and pathological conditions. We made the following significant findings: (1) adipose tissues of diabetic patients with insulin resistance upregulated various Th effector subset regulators; (2) in skin biopsy from patients with psoriasis, and in blood cells from patients with lupus, effector Th subset regulators were more upregulated than downregulated; (3) in rosiglitazone induced failing hearts in ApoE-deficient (KO) mice, various Th subset regulators were upregulated rather than downregulated; (4) aortic endothelial cells activated by proatherogenic stimuli secrete several Th subset-promoting cytokines; (5) in Treg from follicular Th (Tfh)-transcription factor (TF) Bcl6 KO mice, various Th subset regulators were upregulated; whereas in Treg from Th2-TF GATA3 KO mice and HDAC6 KO mice, various Th subset regulators were downregulated, suggesting that Bcl6 inhibits, GATA3 and HDAC6 promote, Treg plasticity; and (6) GATA3 KO, and Bcl6 KO Treg upregulated MHC II molecules and T cell co-stimulation receptors, suggesting that GATA3 and BCL6 inhibit Treg from becoming novel APC-Treg. Our data implies that while HDAC6 and Bcl6 are important regulators of Treg plasticity, GATA3 determine the fate of plastic Tregby controlling whether it will convert in to either Th1-Treg or APC-T-reg. Our results have provided novel insights on Treg plasticity into APC-Treg and Th1-Treg, and new therapeutic targets in metabolic diseases, autoimmune diseases, and inflammatory disorders.
- De novo fatty acid synthesis by Schwann cells is essential for peripheral nervous system myelination. [Journal Article]
- JCJ Cell Biol 2018 Feb 06
- Myelination calls for a remarkable surge in cell metabolism to facilitate lipid and membrane production. Endogenous fatty acid (FA) synthesis represents a potentially critical process in myelinating ...
Myelination calls for a remarkable surge in cell metabolism to facilitate lipid and membrane production. Endogenous fatty acid (FA) synthesis represents a potentially critical process in myelinating glia. Using genetically modified mice, we show that Schwann cell (SC) intrinsic activity of the enzyme essential for de novo FA synthesis, fatty acid synthase (FASN), is crucial for precise lipid composition of peripheral nerves and fundamental for the correct onset of myelination and proper myelin growth. Upon FASN depletion in SCs, epineurial adipocytes undergo lipolysis, suggestive of a compensatory role. Mechanistically, we found that a lack of FASN in SCs leads to an impairment of the peroxisome proliferator-activated receptor (PPAR) γ-regulated transcriptional program. In agreement, defects in myelination of FASN-deficient SCs could be ameliorated by treatment with the PPARγ agonist rosiglitazone ex vivo and in vivo.Our results reveal that FASN-driven de novo FA synthesis in SCs is mandatory for myelination and identify lipogenic activation of the PPARγ transcriptional network as a putative downstream functional mediator.
- PPARγ agonist rosiglitazone switches fuel preference to lipids in promoting thermogenesis under cold exposure in C57BL/6 mice. [Journal Article]
- JPJ Proteomics 2018 Jan 27; 176:24-36
- CONCLUSIONS: In current study, for the first time, PPARγ agonism by rosiglitazone was proved to promote thermogenesis under near-freezing conditions and enhance the heat generating response against cold-induced hypothermia in mice by switching the fuel preference from carbohydrates to lipids. The lipid substrates stored in BAT in response to PPARγ activation are spared for eventual thermogenic activation. These findings thus underline the remarkable actions of PPARγ in the control of energy metabolism in adipose tissues, especially the BAT.
- Plasticizers used in food-contact materials affect adipogenesis in 3T3-L1 cells. [Journal Article]
- JSJ Steroid Biochem Mol Biol 2018 Feb 02
- Recent studies suggest that exposure to some plasticizers, such as Bisphenol A (BPA), play a role in endocrine/metabolic dispruption and can affect lipid accumulation in adipocytes. Here, we investig...
Recent studies suggest that exposure to some plasticizers, such as Bisphenol A (BPA), play a role in endocrine/metabolic dispruption and can affect lipid accumulation in adipocytes. Here, we investigated the adipogenic activity and nuclear receptor interactions of four plasticizers approved for the manufacturing of food-contact materials (FCMs) and currently considered safer alternatives. Differentiating 3T3-L1 mouse preadipocytes were exposed to scalar concentrations (0.01-25 μM) of DiNP (Di-iso-nonyl-phthalate), DiDP (Di-iso-decyl-phthalate), DEGDB (Diethylene glycol dibenzoate), or TMCP (Tri-m-cresyl phosphate). Rosiglitazone, a well-known pro-adipogenic peroxisome proliferator activated receptor gamma (PPARγ) agonist, and the plasticizer BPA were included as reference compounds. All concentrations of plasticizers were able to enhance lipid accumulation, with TMCP being the most effective one. Accordingly, when comparing in silico the ligand binding efficiencies to the nuclear receptors PPARγ and retinoid-X-receptor-alpha (RXRα), TMPC displayed the highest affinity to both receptors. Differently from BPA, the four plasticizers were most effective in enhancing lipid accumulation when added in the mid-late phase of differentiation, thus suggesting the involvement of different intracellular signalling pathways. In line with this, TMCP, DiDP, DiNP and DEGDB were able to activate PPARγ in transient transfection assays, while previous studies demonstrated that BPA acts mainly through other nuclear receptors. qRT-PCR studies showed that all plasticizers were able to increase the expression of CCAAT/enhancer binding protein β (Cebpβ) in the early steps of adipogenesis, and the adipogenesis master gene Pparγ2 in the middle phase, with very similar efficacy to that of Rosiglitazone. In addition, TMCP was able to modulate the expression of both Fatty Acid Binding Protein 4/Adipocyte Protein 2 (Fabp4/Ap2) and Lipoprotein Lipase (Lpl) transcripts in the late phase of adipogenesis. DEGDB increased the expression of Lpl only, while the phthalate DiDP did not change the expression of either late-phase marker genes Fabp4 and Lpl. Taken together, our results suggest that exposure to low, environmentally relevant doses of the plasticizers DiNP, DiDP, DEGDB and TMCP increase lipid accumulation in 3T3-L1 adipocytes, an effect likely mediated through activation of PPARγ and interference at different levels with the transcriptional cascade driving adipogenesis.
- Orally administered berberine ameliorates bleomycin-induced pulmonary fibrosis in mice through promoting activation of PPAR-γ and subsequent expression of HGF in colons. [Journal Article]
- TAToxicol Appl Pharmacol 2018 Feb 03; 343:1-15
- Berberine has been demonstrated to alleviate renal interstitial, liver and myocardial fibrosis when administered orally despite its extremely low bioavailability. Here, we inspected effect of berberi...
Berberine has been demonstrated to alleviate renal interstitial, liver and myocardial fibrosis when administered orally despite its extremely low bioavailability. Here, we inspected effect of berberine on pulmonary fibrosis (PF) and explored underlying mechanisms on the basis of intestinal endocrine. The results showed that either oral or rectal administration of berberine exhibited marked alleviation of bleomycin-induced PF in mice. In contrast, anti-PF activity of berberine disappeared when given by an intravenous injection, implying that it functioned in a gut-dependent manner. Moreover, berberine promoted both mRNA and protein levels of HGF and PTEN in colons, but only their protein levels in lungs of PF mice. In addition, SU11274 but not BPV abolished the anti-PF effect of berberine. In vitro, berberine preferentially induced expression of HGF in fibroblast cells than epithelial, preadipocyte and endothelial cells. Similarly, rosiglitazone and 15dPGJ2 also enhanced expression of HGF in fibroblasts cells, and GW9662 and siPPAR-γ diminished induction of berberine on HGF expression. Berberine could enter into the cytoplasm, activate PPAR-γ directly and synergistically with 15dPGJ2, as shown by an up-regulation of CD36 and aP2 mRNA expression, nuclear translocation and DNA-binding activity of PPAR-γ both in vitro and in vivo. Additionally, GW9662 almost abolished anti-PF effect of berberine and induction of HGF expression in colons. In conclusion, oral administration of berberine displays anti-PF action probably in a colon-dependent manner, and mechanisms involve activation of PPAR-γ and resultant promotion of HGF expression in colonic fibroblasts. The up-regulated HGF arrives in lung tissues via blood circulation to palliate PF.
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- Exenatide induces carcinoembryonic antigen-related cell adhesion molecule 1 expression to prevent hepatic steatosis. [Journal Article]
- HCHepatol Commun 2018; 2(1):35-47
- CONCLUSIONS: Exenatide promotes insulin clearance in parallel with insulin secretion to prevent chronic hyperinsulinemia and the resulting hepatic steatosis, and this contributes to its insulin sensitizing effect. Our data further highlight the relevance of physiologic insulin metabolism in maintaining insulin sensitivity and normal lipid metabolism. (Hepatology Communications 2018;2:35-47).