GW-1100

Cell experiment:

CHO-K1/bFFAR1 or CHO-K1/pcDNA3.1 cells (2×106 cells/2 mL) are loaded with 2.5 μM Fura-2AM fluorescent indicator dye in recording buffer (10 mM HEPES, 140 mM NaCl, 2 mM CaCl2, 21 mM MgCl2, 25 mM KCl, 10 mM glucose, pH 7.4) for 30 min, washed three times with recording buffer, and returned to the incubator for 10 min. Cells are incubated with different concentrations of propionic acid (1, 10 and 30 mM), oleic acid (0-500 μM), linoleic acid (0-200 μM), GW9508 (0-100 μM), ionomycin (2 μM), thapsigargin (2 μM) or vehicle (0.1% DMSO). The fatty acid concentrations used in all experiments are in the range of concentrations of healthy and peripartum cows. In another set of experiments, cells are incubated with either 10 μM GW-1100 for 15 min, 2 μM U73122 for 3 min or vehicle (0.1% DMSO) for 15 min and then stimulated with either 300 μM oleic acid, 100 μM linoleic acid or 10 μM GW9508. Cellular fluorescence (Ca2+) is measured at 509 nm emission with 340/380 nm dual wavelength excitation using a LS55 spectrofluorimeter. Cuvette temperatures are maintained at 37°C with constant stirring[3].

Animal experiment:

Mice[4]Male ddY mice (age, 4 weeks) are housed in cages at 23-24°C with a 12-h light-dark cycle (lights from 8 am to 8 pm) and food and waterad libitum. DHA (50 µg/mouse), the selective GPR40-agonist GW9508 (1.0-25 µg/mouse) and the GPR40 antagonist GW1100 (1-10 µg/mouse) are dissolved in 1% DMSO and the solution is diluted with saline before von Frey testing (1% DMSO final concentration). The doses of GW9508 are chosen based upon our previous publication, whereas GW-1100 is selected on the basis of previous reports and our preliminary experiments. Under a non-anesthetized state, DHA and GW9508 are administered via the intracerebroventricular (i.c.v.) route 10 min before CFA injection, and GW1100 is administered via the i.c.v. route 10 min before GW9508 injection. Flavopiridol (5 and 15 nmol/mouse), a cyclin-dependent kinase inhibitor, is administered by i.c.v. injection into the left lateral ventricle of the mice twice a day (at 9:00 and 19:00) after CFA treatment.

References:

[1]. Stoddart LA, et al. Uncovering the pharmacology of the G protein-coupled receptor GPR40: high apparent constitutive activity in guanosine 5'-O-(3-[35S]thio)triphosphate binding studies reflects binding of an endogenous agonist. Mol Pharmacol. 2007 Apr;71(
[2]. Briscoe CP, et al. Pharmacological regulation of insulin secretion in MIN6 cells through the fatty acid receptor GPR40: identification of agonist and antagonist small molecules. Br J Pharmacol. 2006 Jul;148(5):619-28.
[3]. Manosalva C, et al. Cloning, identification and functional characterization of bovine free fatty acid receptor-1 (FFAR1/GPR40) in neutrophils. PLoS One. 2015 Mar 19;10(3):e0119715.
[4]. Nakamoto K, et al. Hypothalamic GPR40 signaling activated by free long chain fatty acids suppresses CFA-induced inflammatorychronic pain. PLoS One. 2013 Dec 12;8(12):e81563.