linoleic-acid and ciglitazone

Topics: Angiopoietin-Like Protein 4; Angiopoietins; Animals; Cell Differentiation; Cell Line; Epithelial Cells; Humans; Linoleic Acid; Lipogenesis; Mice, Knockout; RNA Interference; RNA, Messenger; Sebaceous Glands; Thiazolidinediones; Time Factors; Transfection; Up-Regulation

Parkinson's disease is a neurodegenerative disorder that is being characterized by the progressive loss of dopaminergic neurons of the nigrostriatal pathway in the brain. The protective effect of omega-6 fatty acids is unclear. There are lots of contradictions in the literature with regard to the cytoprotective role of arachidonic acid. To date, there is no solid evidence that shows the protective role of omega-6 fatty acids in Parkinson's disease. In the current study, the potential of two omega-6 fatty acids (i.e. arachidonic acid and linoleic acid) in alleviating 1-methyl-4-phenylpyridinium (MPP+)-induced cytotoxicity in PC12 cells was examined.. Cultured PC12 cells were either treated with MPP+ alone or co-treated with one of the omega-6 fatty acids for 1 day. Cell viability was then assessed by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.. Cells treated with 500 μM MPP+ for a day reduced cell viability to ~70% as compared to control group. Linoleic acid (50 and 100 μM) significantly reduced MPP+-induced cell death back to ~85-90% of the control value. The protective effect could be mimicked by arachidonic acid, but not by ciglitazone.. Both linoleic acid and arachidonic acid are able to inhibit MPP+-induced toxicity in PC12 cells. The protection is not mediated via peroxisome proliferator-activated receptor gamma (PPAR-γ). Overall, the results suggest the potential role of omega-6 fatty acids in the treatment of Parkinson's disease.

Topics: 1-Methyl-4-phenylpyridinium; Animals; Antiparkinson Agents; Arachidonic Acid; Cell Survival; Drug Evaluation, Preclinical; Linoleic Acid; Neuroprotective Agents; PC12 Cells; Rats; Thiazolidinediones

MicroRNAs (miRNAs) regulate several aspects of the morphogenesis and homeostasis of the skin and its appendages, and miRNA deregulation has been shown to be associated or even causally related to several skin diseases.. To evaluate the differential expression of miRNAs during sebaceous lipogenesis.. Inhibition of global miRNA activity in human SZ95 sebaceous gland cells was achieved by transfection with siRNAs directed against the DICER transcript, encoding a key enzyme of miRNA biogenesis. Sebaceous lipogenesis was induced in SZ95 sebocytes by addition of linoleic acid (LA) and ciglitazone (CIG) and microarray-based miRNA expression profiles were obtained on an Agilent platform. The expression of selected miRNA candidates was measured by Taqman quantitative real-time RT-PCR. Increased activity of one validated miRNA was attained by transfecting SZ95 sebocytes with miR-574-3p mimics.. Downregulation of sebaceous lipogenesis was detected in DICER-impaired SZ95 sebocytes. Using microarrays, we identified twelve significantly upregulated and nine significantly downregulated miRNAs in LA- and CIG-treated SZ95 sebocytes as compared to non-treated cells. Validation of a subset of miRNA candidates by qRT-PCR confirmed upregulation of mIR-203 and miR-574-3p and downregulation of miR-7 during sebaceous lipogenesis. The two upregulated miRNAs have been previously implied in keratinocyte differentiation. Increased activity of miR-574-3p augmented lipogenesis in SZ95 sebocytes.. Global miRNA activity is essential for lipid synthesis in human SZ95 sebocytes. Individual miRNAs are likely to play a significant role during sebaceous lipogenesis.

Topics: Cell Line; Cells, Cultured; DEAD-box RNA Helicases; Humans; In Vitro Techniques; Linoleic Acid; Lipid Metabolism; Lipogenesis; MicroRNAs; Ribonuclease III; Sebaceous Glands; Thiazolidinediones

Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands seem to induce anticancer effects on prostate cancer cells, but the mechanism is not clear. The effect of PPARgamma ligands omega-6 fatty acids and ciglitazone (2-15 microM)--on proliferation, and apoptosis of LNCaP, PC-3, DU145, CA-K and BPH-K cells was studied. PPARgamma ligands led to: (1) reduction of proliferation (20-50%) of all the studied cell lines, (2) stimulation of differentiation of prostate cancer cells through an increased expression (1.5-3-fold: LNCaP, DU145, BPH-K) or reexpression (PC-3, CA-K) of E-cadherin with parallel inhibition of N-cadherin expression (PC-3, CA-K) and (3) down-regulation (1-2-fold) of beta-catenin and c-myc expression. The selective PPARgamma antagonist GW9662 abolished the effect of those ligands on prostate cancer cells. These results suggest that inhibition of beta-catenin and in effect c-myc expression through activation of PPARgamma may help prostate cancer cells to restore several characteristics of normal prostate cells phenotype.

Topics: Anilides; Antineoplastic Agents; Apoptosis; beta Catenin; Cadherins; Cell Differentiation; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Linoleic Acid; Male; PPAR gamma; Prostatic Neoplasms; Proto-Oncogene Proteins c-myc; Thiazolidinediones

In addition to inhibiting cholesterol biosynthesis, statins increase the conversion of linoleic acid to its derivatives, in particular to arachidonic acid, both in vivo and in vitro. Desaturases are the rate-limiting enzymes in this metabolic process and statins markedly enhance delta5 desaturase activity. To evaluate the delta5 desaturase gene expression and the transcription factors involved, THP-1 cells (a monocytic cell line) were incubated with 5 microM simvastatin for different time periods. The activity of the enzyme, evaluated as product/precursor ratio in the metabolic pathway (starting from [1-(14)C] linoleic acid), increased in treated cells with respect to controls after 24 h, whereas, mRNA levels of the delta5 desaturase increased after 12 h of incubation with simvastatin. Fatty acid desaturase genes are regulated by both sterol regulatory element binding proteins (SREBPs) and peroxisome proliferators activated receptors (PPARs). Both PPARalpha (WY 14643 and fenofibrate) and PPARgamma (ciglitazone) agonists did not affect linoleic acid conversion and the delta5 desaturase activity at any time considered (8-48 h), but they increased the delta5 desaturase mRNA levels, after 48 h; only fenofibrate showed a synergistic effect with simvastatin at this time, with a concomitantly increase in PPARalpha expression and beta-oxidation. Simvastatin alone increased SREBP-1 levels with respect to controls, starting from 8 h of incubation, whereas PPARalpha and linoleic acid beta-oxidation (a PPARalpha mediated process) were not affected after 48 h of incubation. These results taken together suggest that SREBP-1 is involved in the early regulation of delta5 desaturase gene by simvastatin, in THP-1 cells.

Topics: Anticholesteremic Agents; Arachidonic Acid; Cell Line; Cholesterol; Delta-5 Fatty Acid Desaturase; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Induction; Fatty Acid Desaturases; Fenofibrate; Humans; Linoleic Acid; Lipid Metabolism; Monocytes; Peroxisome Proliferators; PPAR alpha; PPAR gamma; Pyrimidines; RNA, Messenger; Simvastatin; Sterol Regulatory Element Binding Protein 1; Thiazolidinediones; Time Factors; Transcription, Genetic

The trans10,cis12 (t10c12) isomer of conjugated linoleic acid (CLA) has been shown to inhibit heparin-releasable lipoprotein lipase activity, reduce lipid stores in cultured 3T3-L1 adipocytes, and, when fed to mice, reduce body fat gain. We now report that t10c12 CLA significantly reduced leptin secretion from cultured 3T3-L1 adipocytes, and reduced leptin mRNA levels within the cells. Similar effects were produced by conjugated nonadecadienoic acid (a 19-carbon CLA cognate that is more effective than CLA in reducing body fat gain in mice), the lipoxygenase inhibitor nordihydroguaiaretic acid (which is synergistic with CLA in reducing body fat gain in mice), and ciglitazone (TZD, a PPARgamma agonist). Feeding mice diet supplemented with 0.5% t10c12 CLA for 4 weeks significantly reduced body fat gain, serum leptin levels and adipocyte leptin mRNA expression, without affecting feed intake or body weight. These data provide new insights into apparent mechanistic similarities among t10c12 CLA, CNA, NDGA, and TZD.

Topics: 3T3 Cells; Adipocytes; Animals; Antioxidants; Hypoglycemic Agents; Leptin; Linoleic Acid; Male; Masoprocol; Mice; Mice, Inbred ICR; Thiazoles; Thiazolidinediones