Biology subjects

Solis, K. H.

Publications and source records attributed to Solis, K. H..

3 recordsLinked to original sources

bioRxiv2025

Antidepressants interact with an LPA3 receptor binding site: functional and docking studies

The action of the antidepressants imipramine, amitriptyline, and paroxetine on LPA3 receptors was studied in cellulo, using receptor-transfected HEK 293 Flp-In TREx cells, and in silico, through docking simulations. These drugs showed a low affinity for LPA3 receptors with lesser efficacy than LPA (paroxetine {approx} 60% and imipramine and amitriptyline {approx} 30%). When LPA-treated cells (with the agonist present) were challenged with the antidepressants, paroxetine triggered a robust increase in intracellular calcium, whereas imipramine and amitriptyline decreased the calcium concentration below baseline values. For ERK 1/2 phosphorylation, imipramine induced a rapid and potent increase, whereas amitriptyline and paroxetine reduced ERK 1/2 phosphorylation below baseline. Similarly, imipramine produced rapid and robust ERK phosphorylation in LPA-stimulated cells, but amitriptyline decreased ERK 1/2 phosphorylation. Activation with the antidepressants leads to LPA3 internalization; dramatic morphological changes accompany these actions. Docking simulations showed these drugs interact with an LPA3 receptor pocket, denominated Upper Cavity. Although the agonist binding cavity was the same, the amino acids interacting with the various ligands were distinct due to their different chemical structure. The manuscript advances knowledge on the mechanisms of antidepressant effects on LPA3 receptors, which might have potential therapeutic implications.

pharmacology and toxicology↗

bioRxiv2024

LPA3: Pharmacodynamic differences between lysophosphatidic acid and oleoyl-methoxy glycerophosphothionate. Biased agonism, two sites.

Lysophosphatidic acid (LPA) and oleoyl-methoxy glycerophosphothionate (OMPT) increased LPA3 phosphorylation; OMPT being considerably more potent than LPA. OMPT was also more potent than LPA to activate ERK 1/2. In contrast, to increase intracellular calcium OMPT was less effective than LPA. LPA-induced LPA3-{beta}-arrestin 2 interaction was fast and robust, whereas that induced by OMPT was only detected at 60 min of incubation. LPA- and OMPT-induced receptor internalization was fast but that of OMPT was more marked. LPA-induced internalization was blocked by Pitstop 2, whereas OMPT-induced receptor internalization was partially inhibited by Pitstop 2 and Filipin and entirely by the combination of both. The data again indicate differences in the actions of these agonists. When LPA-stimulated cells were rechallenged with 1 {micro}M LPA, hardly any response was detected, i.e., a "refractory" state was induced. However, if OMPT was used as the second stimulus, a conspicuous and robust response was observed. These data again suggest the possibility that two binding sites for these agonists might exist in the LPA3 receptor, one showing a very high affinity for OMPT and another, likely shared by LPA and OMPT (structural analogs) with lower affinity. One sentence summaryOMPT, oleoyl-methoxy glycerophosphothionate, a biased agonits interacting with an additional binding site in LPA3 receptors.

biochemistry↗

bioRxiv2024

LPA3 receptors have orthosteric and allosteric binding sites evidenced under docking studies.

Comparative studies using (lysophosphatidic acid) LPA and the synthetic agonist, oleoyl-methoxy glycerophosphothionate, OMPT, in cells expressing the LPA3 receptor revealed differences in the action of these agents. The possibility that more than one recognition cavity might exist for these ligands in the LPA3 receptor was considered. We performed agonist docking studies exploring the whole protein to obtain tridimensional details of the ligand-receptor interaction. Functional in-cellulo experiments using mutants were also executed. Our work includes blind docking using the unrefined and refined proteins subjected to hot spot predictions. Distinct ligand protonation (charge-1 and-2) states were evaluated. One LPA recognition cavity is located near the lower surface of the receptor close to the cytoplasm (Lower Cavity). OMPT displayed an affinity for an additional identification cavity detected in the transmembrane and extracellular regions (Upper Cavity). Docking targeted to Trp102 favored binding of both ligands in the transmembrane domain near the extracellular areas (Upper Cavity), but the associating amino acids were not identical due to close sub-cavities. In the in-cellulo studies, LPA action was much less affected by the distinct mutations than that of OMPT (which was almost abolished). Docking and functional data suggest distinct agonist binding cavities in the LPA3 receptor

biochemistry↗