Fatty Alcohol Phosphates are Subtype-Selective Agonists and Antagonists of Lysophosphatidic Acid Receptors

Abstract

A more complete understanding of the physiological and pathological role of lysophosphatidic acid (LPA) requires receptor subtype-specific agonists and antagonists. Here, we report the synthesis and pharmacological characterization of fatty alcohol phosphates (FAP) containing saturated hydrocarbon chains from 4 to 22 carbons in length. Selection of FAP as the lead structure was based on computational modeling as a minimal structure that satisfies the two-point pharmacophore developed earlier for the interaction of LPA with its receptors. Decyl and dodecyl FAPs (FAP-10 and FAP-12) were specific agonists of LPA 2 (EC 50 ϭ 3.7 Ϯ 0.2 M and 700 Ϯ 22 nM, respectively), yet selective antagonists of LPA 3 (K i ϭ 90 nM for FAP-12) and FAP-12 was a weak antagonist of LPA 1 . Neither LPA 1 nor LPA 3 receptors were activated by FAPs; in contrast, LPA 2 was activated by FAPs with carbon chains between 10 and 14. Computational modeling was used to evaluate the interaction between individual FAPs (8 to 18) with LPA 2 by docking each compound in the LPA binding site. FAP-12 displayed the lowest docked energy, consistent with its lower observed EC 50 . The inhibitory effect of FAP showed a strong hydrocarbon chain length dependence with C12 being optimum in the Xenopus laevis oocytes and in LPA 3 -expressing RH7777 cells. FAP-12 did not activate or interfere with several other G-protein-coupled receptors, including S1P-induced responses through S1P 1,2,3,5 receptors. These data suggest that FAPs are ligands of LPA receptors and that FAP-10 and FAP-12 are the first receptor subtype-specific agonists for LPA 2 .

α‐Substituted Phosphonate Analogues of Lysophosphatidic Acid (LPA) Selectively Inhibit Production and Action of LPA

“…These cell lines have been used extensively for the characterization of LPA GPCR ligands because RH7777 cells are intrinsically unresponsive to LPA, and CHO cells show minimal endogenous responses to LPA unless transfected with LPA 4 . [14,24,44] The oleoyl chain-containing methylene phosphonate LPA analogue 5a, in which a methylene unit replaces the oxygen atom, is a selective, full agonist for LPA 2 with an EC 50 value of 281 nM. Interestingly, replacement of the oleoyl chain in 5a with the palmitoyl chain in 5b switched the activity of this partially selective agonist to that of modest antagonist.…”

“…EC 50 , IC 50 , and K i values were calculated as described. [24] PPARγ activation assay PPARγ activation was performed using CV-1 cells transfected with an acyl-coenzyme A oxidase-luciferase (PPRE-Acox-Rluc) reporter gene construct as previously reported. [45] Briefly, CV-1 cells were plated in 96-well plates at a density of 1×10 4 cells per well in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum.…”

“…IC 50 and K i values were calculated as described. [24] Structures of LPA and its analogues. Diastereoselective hydrophosphonylation with chiral complex Al(salalen) 27.…”

“…Several groups have reported the characterization of the LPA agonists and antagonists. [20][21][22][23][24][25][26][27][28][29] Appropriately validated compounds are essential to advance in vivo studies, particularly in view of potential off-target effects. The development of more selective, more stable, more potent, and more druglike agonists and antagonists is eagerly awaited, and is the bottleneck in therapeutic exploration.…”

7TM Receptors

“…Targeted deletion of LPA receptors has clarified signalling pathways and identified physiological and pathophysiological roles. LPA has also been described to be an agonist at PPARg receptors (McIntyre et al, 2003), although the physiological significance of this observation remains unclear (Simon et al, 2005).FAP12 has antagonist activity at LPA 1 and LPA 3 receptors (Virag et al, 2003). The selectivity of these antagonists is less than two orders of magnitude.…”