GW 7647

GW7647 is a potent PPARα agonist, with EC50s of 6 nM, 1.1 μM, and 6.2 μM for human PPARα, PPARγ and PPARδ, respectively.

In Vitro:GW7647 (1 μM) causes a significant increase of PDZK1 protein expression to 129.7 ± 6.5% of vehicle treated control in Caco2BBE cells in the absence and presence of IL-1β. GW7647 also attenuates the IL-1β-mediated decrease in PDZK1 expression[1]. GW7647 (50 nM) stimulates the PI3K phosphorylation followed by the Akt (Ser473) phosphorylation, which induces NOS1 phosphorylation increased the amounts of NO released in the stripped antral mucosa. GW7647 (50 nM) enhances the initial phase of Ca2+-regulated exocytotic events stimulated by ACh in antral mucous cells, but GW7647 alone does not evoke any exocytotic event. GW7647 plus ACh stimulates the effects of wortmannin (50 nM) and AKT-inh (100 nM) on the exocytotic events in antral mucous cells[2]. GW 7647 (100 nM) reduces the AQP9 protein abundance by 43%, but it shows not significant effect at 10 and 1,000 nM in WIF-B9 hepatocytes. GW 7647 (100 nM) causes a 24% reduction in AQP9 protein abundance in HepG2 cells, however, it does not significantly increase the protein abundance of L-FABP in HepG2 hepatocytes[3].

In Vivo:GW7647 (3 mg/kg per day) does not prevent the development of cardiac hypertrophy, but it prevents the decline in left ventricular ejection fraction in vivo[4].

References:
[1]. Luo M, et al. IL-1β-Induced Downregulation of the Multifunctional PDZ Adaptor PDZK1 Is Attenuated by ERK Inhibition, RXRα, or PPARα Stimulation in Enterocytes. Front Physiol. 2017 Feb 7;8:61. [2]. Tanaka S, et al. PPARα induced NOS1 phosphorylation via PI3K/Akt in guinea pig antral mucous cells: NO-enhancement in Ca(2+)-regulated exocytosis. Biomed Res. 2016;37(3):167-78. [3]. Lebeck J, et al. Hepatic AQP9 expression in male rats is reduced in response to PPARα agonist treatment. Am J Physiol Gastrointest Liver Physiol. 2015 Feb 1;308(3):G198-205. [4]. Lam VH, et al. Activating PPARα prevents post-ischemic contractile dysfunction in hypertrophied neonatal hearts. Circ Res. 2015 Jun 19;117(1):41-51. [5]. Brown PJ, et al. Identification of a subtype selective human PPARalpha agonist through parallel-array synthesis. Bioorg Med Chem Lett. 2001 May 7;11(9):1225-7.

Ligands of peroxisome proliferator-activated receptor-alpha promote glutamate transporter-1 endocytosis in astrocytes.[Pubmed:28323206]

Int J Biochem Cell Biol. 2017 May;86:42-53.

Astrocytes, a stellate-shape glial population in the central nervous system (CNS), maintain glutamate homeostasis in adult CNS by undergoing glutamate uptake at the synapse through their glutamate transporter-1 (GLT-1). Peroxisome proliferator-activated receptor-alpha (PPARalpha) can be activated by endogenous saturated fatty acids to regulate astrocytic lipid metabolism and functions. However, it is unclear if PPARalpha can exert the regulatory action on GLT-1 expression in astrocytes. This study showed that treatment with palmitic acid (PA) and the other two PPARalpha agonists (GW 7647 and WY 14,643) caused no change in the morphology of astrocytes, whereas membranous GLT-1 protein levels in astrocytes were significantly decreased by PA and PPARalpha agonists. Through lentivirus-mediated overexpression of GLT-1 tagged with red fluorescent protein (GLT-1-RFP), we also observed that GLT-1-RFP puncta in the processes of astrocytes were inhibited by the PPARalpha agonists. This reduction was prevented by the addition of the PPARalpha antagonist, GW6471. GLT-1-RFP was co-localized to the early endosome marker-EEA1 in astrocytes treated with the PPARalpha agonists. Moreover, PPARalpha-induced inhibition in membranous GLT-1 expression was abolished by the addition of dynamin inhibitor (dynasore). Furthermore, the co-treatment of astrocytes with PPARalpha agonists and dynasore, or with PPARalpha agonists and protein kinase C (PKC) inhibitor bis-indolylmaleimide 1 (BIS1), prevented the endocytosis of GLT-1-RFP. Based on the results, we conclude that the PPARalpha agonists increased GLT-1 endocytosis in astrocytes possibly through the PKC signaling pathway. In addition, our findings provide important information of PPARalpha involvement in the downregulation of astrocytic glutamate uptake via the promoted GLT-1 endocytosis.

Hepatic AQP9 expression in male rats is reduced in response to PPARalpha agonist treatment.[Pubmed:25477377]

Am J Physiol Gastrointest Liver Physiol. 2015 Feb 1;308(3):G198-205.

The peroxisome proliferator receptor alpha (PPARalpha) is a key regulator of the hepatic response to fasting with effects on both lipid and carbohydrate metabolism. A role in hepatic glycerol metabolism has also been found; however, the results are somewhat contradictive. Aquaporin 9 (AQP9) is a pore-forming transmembrane protein that facilitates hepatic uptake of glycerol. Its expression is inversely regulated by insulin in male rodents, with increased expression during fasting. Previous results indicate that PPARalpha plays a crucial role in the induction of AQP9 mRNA during fasting. In the present study, we use PPARalpha agonists to explore the effect of PPARalpha activation on hepatic AQP9 expression and on the abundance of enzymes involved in glycerol metabolism using both in vivo and in vitro systems. In male rats with free access to food, treatment with the PPARalpha agonist WY 14643 (3 mg.kg(-1).day(-1)) caused a 50% reduction in hepatic AQP9 abundance with the effect being restricted to AQP9 expressed in periportal hepatocytes. The pharmacological activation of PPARalpha had no effect on the abundance of GlyK, whereas it caused an increased expression of hepatic GPD1, GPAT1, and L-FABP protein. In WIF-B9 and HepG2 hepatocytes, both WY 14643 and another PPARalpha agonist GW 7647 reduced the abundance of AQP9 protein. In conclusion, pharmacological PPARalpha activation results in a marked reduction in the abundance of AQP9 in periportal hepatocytes. Together with the effect on the enzymatic apparatus for glycerol metabolism, our results suggest that PPARalpha activation in the fed state directs glycerol into glycerolipid synthesis rather than into de novo synthesis of glucose.

PPARalpha agonists inhibit nitric oxide production by enhancing iNOS degradation in LPS-treated macrophages.[Pubmed:17891158]

Br J Pharmacol. 2007 Dec;152(7):1081-91.

BACKGROUND AND PURPOSE: Nitric oxide (NO) production through the inducible nitric oxide synthase (iNOS) pathway is increased in response to pro-inflammatory cytokines and bacterial products. In inflammation, NO has pro-inflammatory and regulatory effects. Peroxisome proliferator-activated receptors (PPARs), members of the nuclear steroid receptor superfamily, regulate not only metabolic but also inflammatory processes. The aim of the present study was to investigate the role of PPARalpha in the regulation of NO production and iNOS expression in activated macrophages. EXPERIMENTAL APPROACH: The effects of PPARalpha agonists were investigated on iNOS mRNA and protein expression, on NO production and on the activation of transcription factors NF-kappaB and STAT1 in J774 murine macrophages exposed to bacterial lipopolysaccharide (LPS). KEY RESULTS: PPARalpha agonists GW7647 and WY14643 reduced LPS-induced NO production in a dose-dependent manner as measured by the accumulation of nitrite into the culture medium. However, PPARalpha agonists did not alter LPS-induced iNOS mRNA expression or activation of NF-kappaB or STAT1 which are important transcription factors for iNOS. Nevertheless, iNOS protein levels were reduced by PPARalpha agonists in a time-dependent manner. The reduction was markedly greater after 24 h incubation than after 8 h incubation. Treatment with the proteasome inhibitors, lactacystin or MG132, reversed the decrease in iNOS protein levels caused by PPARalpha agonists. CONCLUSIONS AND IMPLICATIONS: The results suggest that PPARalpha agonists reduce LPS-induced iNOS expression and NO production in macrophages by enhancing iNOS protein degradation through the proteasome pathway. The results offer an additional mechanism underlying the anti-inflammatory effects of PPARalpha agonists.

Regulation of cytokine expression by ligands of peroxisome proliferator activated receptors.[Pubmed:11884448]

J Immunol. 2002 Mar 15;168(6):2795-802.

Peroxisome proliferator activated receptors (PPARs) are ligand-activated transcription factors with diverse actions including adipocyte differentiation and lipid metabolism. Recent studies have revealed anti-inflammatory activities, but the majority of these studies have been performed in monocyte/macrophages. In these studies, we investigate the effects of PPAR ligands in murine mitogen-activated splenocytes. Ciglitazone, a PPARgamma ligand, consistently decreased IFN-gamma and IL-2 production by mitogen-activated splenocytes and had modest effects on splenocyte proliferation. The effects of WY14,643, a representative of the fibrate class of PPARalpha ligands, on splenocyte proliferation and IL-2 levels are less marked than those observed with the PPARgamma ligand. In addition, treatment with WY14,643 and other fibrates led to marked increases in supernatant concentrations of IL-4. However, treatment with a potent and specific PPARalpha ligand (GW7,647) did not augment IL-4. Also, WY14,643 induced IL-4 expression in splenocytes from PPARalpha knockout mice, suggesting that the fibrate effect on IL-4 was largely through a PPARalpha-independent mechanism. This increase in IL-4 was associated with and causatively related to augmented expression of CD23 by CD45R/B220(+) cells. We also demonstrate that PPARgamma gene expression is up-regulated in T cells by mitogen activation, that it is positively regulated by IL-4 and WY14,643, and that it is blocked by anti-IL-4. Finally, we demonstrate that WY14,643 can modestly augment IL-4 promoter activity in a PPARalpha-independent manner. In concert, these findings support the roles of PPAR ligands in modulating inflammatory responses involving lymphocytes but also establish potent effects of the fibrate class of PPARalpha ligands on IL-4 expression that are receptor independent.

Peroxisome proliferator-activated receptor-alpha regulates fatty acid utilization in primary human skeletal muscle cells.[Pubmed:11916905]

Diabetes. 2002 Apr;51(4):901-9.

In humans, skeletal muscle is a major site of peroxisome proliferator-activated receptor-alpha (PPAR-alpha) expression, but its function in this tissue is unclear. We investigated the role of hPPAR-alpha in regulating muscle lipid utilization by studying the effects of a highly selective PPAR-alpha agonist, GW7647, on [(14)C]oleate metabolism and gene expression in primary human skeletal muscle cells. Robust induction of PPAR-alpha protein expression occurred during muscle cell differentiation and corresponded with differentiation-dependent increases in oleate oxidation. In mature myotubes, 48-h treatment with 10-1,000 nmol/l GW7647 increased oleate oxidation dose-dependently, up to threefold. Additionally, GW7647 decreased oleate esterification into myotube triacylglycerol (TAG), up to 45%. This effect was not abolished by etomoxir, a potent inhibitor of beta-oxidation, indicating that PPAR-alpha-mediated TAG depletion does not depend on reciprocal changes in fatty acid catabolism. Consistent with its metabolic actions, GW7647 induced mRNA expression of mitochondrial enzymes that promote fatty acid catabolism; carnitine palmityltransferase 1 and malonyl-CoA decarboxylase increased approximately 2-fold, whereas pyruvate dehydrogenase kinase 4 increased 45-fold. Expression of several genes that regulate glycerolipid synthesis was not changed by GW7647 treatment, implicating involvement of other targets to explain the TAG-depleting effect of the compound. These results demonstrate a role for hPPAR-alpha in regulating muscle lipid homeostasis.

Identification of a subtype selective human PPARalpha agonist through parallel-array synthesis.[Pubmed:11354382]

Bioorg Med Chem Lett. 2001 May 7;11(9):1225-7.

Using solid-phase, parallel-array synthesis, a series of urea-substituted thioisobutyric acids was synthesized and assayed for activity on the human PPAR subtypes. GW7647 (3) was identified as a potent human PPARalpha agonist with approximately 200-fold selectivity over PPARgamma and PPARdelta, and potent lipid-lowering activity in animal models of dyslipidemia. GW7647 (3) will be a valuable chemical tool for studying the biology of PPARalpha in human cells and animal models of disease.