| Autor: |
Mahmud ZA; Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, G12 8QQ, Scotland, United Kingdom., Jenkins L; Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, G12 8QQ, Scotland, United Kingdom., Ulven T; Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark., Labéguère F; Galapagos SASU, 102 Avenue Gaston Roussel, 93230, Romainville, France.; Evotec, 195 Route d'Espagne, 31100, Toulouse, France., Gosmini R; Galapagos SASU, 102 Avenue Gaston Roussel, 93230, Romainville, France., De Vos S; Galapagos NV, Generaal De Wittelaan L11 A3, 2800, Mechelen, Belgium., Hudson BD; Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, G12 8QQ, Scotland, United Kingdom., Tikhonova IG; School of Pharmacy, Medical Biology Centre, Queen's University Belfast, Belfast, BT9 7BL, United Kingdom., Milligan G; Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, G12 8QQ, Scotland, United Kingdom. Graeme.Milligan@glasgow.ac.uk. |
| Abstrakt: |
Medium chain fatty acids can activate the pro-inflammatory receptor GPR84 but so also can molecules related to 3,3'-diindolylmethane. 3,3'-Diindolylmethane and decanoic acid acted as strong positive allosteric modulators of the function of each other and analysis showed the affinity of 3,3'-diindolylmethane to be at least 100 fold higher. Methyl decanoate was not an agonist at GPR84. This implies a key role in binding for the carboxylic acid of the fatty acid. Via homology modelling we predicted and confirmed an integral role of arginine 172 , located in the 2nd extracellular loop, in the action of decanoic acid but not of 3,3'-diindolylmethane. Exemplars from a patented series of GPR84 antagonists were able to block agonist actions of both decanoic acid and 3,3'-diindolylmethane at GPR84. However, although a radiolabelled form of a related antagonist, [ 3 H]G9543, was able to bind with high affinity to GPR84, this was not competed for by increasing concentrations of either decanoic acid or 3,3'-diindolylmethane and was not affected adversely by mutation of arginine 172 . These studies identify three separable ligand binding sites within GPR84 and suggest that if medium chain fatty acids are true endogenous regulators then co-binding with a positive allosteric modulator would greatly enhance their function in physiological settings. |
