Background/Aims: CID16020046 blocks the effect of the lipid lysophosphatidylinositol (LPI) at its receptor, GPR55. CID16020046 and another antagonist, ML193, have been used to investigate GPR55-mediated effects of LPI on cells, tissues, and in vivo. Here we describe the structure-activity relationship of CID16020046. Methods: Yeast or human cells were engineered to express GPR55 or control receptors. Cells were pretreated with a test agent before agonist challenge. Functional responses were quantified by yeast gene-reporter or calcium imaging. Results: Three substituents around the central pyrazololactam core of CID16020046 are each tolerant to substitution without abolishing GPR55 activity. Analogues of CID16020046 with potency at GPR55 ranging >1,000-fold are described, including several lacking activity up to the top concentration tested. One analogue, compound 1 (GSK875734A), has approximately 50-fold greater potency than CID16020046 in an inverse agonist assay. CID16020046, ML193 and 2 further antagonists (ML191 and ML192) all block the effect of a surrogate agonist at human GPR55. ML193, CID16020046 and several other examples of the pyrazololactam chemotype were also shown to antagonise rat GPR55. Conclusion: These data confirm the utility of CID16020046 and ML193 as tools to investigate the physiological role of GPR55, and offer starting points for GPR55 antagonists with optimised pharmacokinetic or other properties.

1.
Henstridge CM, Brown AJ, Waldhoer M: GPR55:Metabolic help or hindrance? Trends Endocrinol Metab 2016; 27: 606–608.
2.
Reggio PH, Shore DM: The therapeutic potential of orphan GPCRs, GPR35 and GPR55. Front Pharmacol 2015; 6: 1–22.
3.
Henstridge CM, Balenga NA, Kargl J, Andradas C, Brown AJ, Irving A, Sanchez C, Waldhoer M: Minireview: recent developments in the physiology and pathology of the lysophosphatidylinositol-sensitive receptor GPR55. Mol Endocrinol 2011; 25: 1835–1848.
4.
Liu B, Song S, Jones PM, Persaud SJ: GPR55:From orphan to metabolic regulator? Pharmacol Ther 2015; 145: 35–42.
5.
Oka S, Toshida T, Maruyama K, Nakajima K, Yamashita A, Sugiura T: 2-arachidonoyl-sn-glycero-3-phosphoinositol: a possible natural ligand for GPR55. J Biochem 2009; 145: 13–20.
6.
Imbernon M, Whyte L, Diaz-Arteaga A, Russell WR, Moreno NR, Vazquez MJ, Gonzalez CR, Diaz-Ruiz A, Lopez M, Malagon MM, Ross RA, Dieguez C, Nogueiras R: Regulation of GPR55 in rat white adipose tissue and serum LPI by nutritional status, gestation, gender and pituitary factors. Mol Cell Endocrinol 2014; 383: 159–169.
7.
Pineiro R, Falasca M: Lysophosphatidylinositol signalling: New wine from an old bottle. Biochim Biophys Acta 2012; 1821: 694–705.
8.
Kremshofer J, Siwetz M, Berghold VM, Lang I, Huppertz B, Gauster M: A role for GPR55 in human placental venous endothelial cells. Histochem Cell Biol 2015; 144: 49–58.
9.
Bondarenko AI, Malli R, Graier WF: The GPR55 agonist lysophosphatidylinositol directly activates intermediate-conductance Ca2+-activated K+ channels. Pflugers Arch 2011; 462: 245–255.
10.
Bondarenko AI, Malli R, Graier WF: The GPR55 agonist lysophosphatidylinositol acts as an intracellular messenger and bidirectionally modulates Ca2+-activated large-conductance K+ channels in endothelial cells. Pflugers Arch 2011; 461: 177–189.
11.
Kotsikorou E, Sharir H, Shore DM, Hurst DP, Lynch DL, Madrigal KE, Heynen-Genel S, Milan LB, Chung TD, Seltzman HH, Bai Y, Caron MG, Barak LS, Croatt MP, Abood ME, Reggio PH: Identification of the GPR55 antagonist binding site using a novel set of high-potency GPR55 selective ligands. Biochemistry 2013; 52: 9456–9469.
12.
Kargl J, Brown AJ, Andersen L, Dorn G, Schicho R, Waldhoer M, Heinemann A: A selective antagonist reveals a potential role of G protein-coupled receptor 55 in platelet and endothelial cell function. J Pharmacol Exp Ther 2013; 346: 54–66.
13.
Yu J, Deliu E, Zhang XQ, Hoffman NE, Carter RL, Grisanti LA, Brailoiu GC, Madesh M, Cheung JY, Force T, Abood ME, Koch WJ, Tilley DG, Brailoiu E: Differential activation of cultured neonatal cardiomyocytes by plasmalemmal versus intracellular G protein-coupled receptor 55. J Biol Chem 2013; 288: 22481–22492.
14.
Walsh SK, Hector EE, Andreasson AC, Jonsson-Rylander AC, Wainwright CL: GPR55 deletion in mice leads to age-related ventricular dysfunction and impaired adrenoceptor-mediated inotropic responses. PLoS One 2014; 9:e108999.
15.
Deliu E, Sperow M, Console-Bram L, Carter RL, Tilley DG, Kalamarides DJ, Kirby LG, Brailoiu GC, Brailoiu E, Benamar K, Abood ME: The lysophosphatidylinositol receptor GPR55 modulates pain perception in the periaqueductal gray. Mol Pharmacol 2015; 88: 265–272.
16.
Staton PC, Hatcher JP, Walker DJ, Morrison AD, Shapland EM, Hughes JP, Chong E, Mander PK, Green PJ, Billinton A, Fulleylove M, Lancaster HC, Smith JC, Bailey LT, Wise A, Brown AJ, Richardson JC, Chessell IP: The putative cannabinoid receptor GPR55 plays a role in hyperalgesia associated with inflammatory and neuropathic pain. Pain 2008; 139: 225–236.
17.
Gangadharan V, Selvaraj D, Kurejova M, Njoo C, Gritsch S, Skoricova D, Horstmann H, Offermanns S, Brown AJ, Kuner T, Tappe-Theodor A, Kuner R: A novel biological role for the phospholipid lysophosphatidylinositol in nociceptive sensitization via activation of diverse G-protein signalling pathways in sensory nerves in vivo. Pain 2013; 154: 2801–2812.
18.
AlSuleimani YM, Hiley CR: The GPR55 agonist lysophosphatidylinositol relaxes rat mesenteric resistance artery and induces Ca(2+) release in rat mesenteric artery endothelial cells. Br J Pharmacol 2015; 172: 3043–3057.
19.
Karpinska O, Baranowska-Kuczko M, Malinowska B, Kloza M, Kusaczuk M, Gegotek A, Golec P, Kasacka I, Kozlowska H: Mechanisms of L-alpha-lysophosphatidylinositol-induced relaxation in human pulmonary arteries. Life Sci 2018; 192: 38–45.
20.
Sumida H, Lu E, Chen H, Yang Q, Mackie K, Cyster JG: GPR55 regulates intraepithelial lymphocyte migration dynamics and susceptibility to intestinal damage. Sci Immunol 2017; 2.
21.
Montecucco F, Bondarenko AI, Lenglet S, Burger F, Piscitelli F, Carbone F, Roth A, Liberale L, Dallegri F, Brandt KJ, Fraga-Silva RA, Stergiopulos N, Di Marzo V, Mach F: Treatment with the GPR55 antagonist CID16020046 increases neutrophil activation in mouse atherogenesis. Thromb Haemost 2016; 116: 987–997.
22.
Stancic A, Jandl K, Hasenohrl C, Reichmann F, Marsche G, Schuligoi R, Heinemann A, Storr M, Schicho R: The GPR55 antagonist CID16020046 protects against intestinal inflammation. Neurogastroenterol Motil 2015; 27: 1432–1445.
23.
Hurst K, Badgley C, Ellsworth T, Bell S, Friend L, Prince B, Welch J, Cowan Z, Williamson R, Lyon C, Anderson B, Poole B, Christensen M, McNeil M, Call J, Edwards JG: A putative lysophosphatidylinositol receptor GPR55 modulates hippocampal synaptic plasticity. Hippocampus 2017; 27: 985–998.
24.
Hofmann NA, Yang J, Trauger SA, Nakayama H, Huang L, Strunk D, Moses MA, Klagsbrun M, Bischoff J, Graier WF: The GPR55 agonist, L-alpha-lysophosphatidylinositol, mediates ovarian carcinoma cell-induced angiogenesis. Br J Pharmacol 2015; 172: 4107–4118.
25.
Zhou XL, Guo X, Song YP, Zhu CY, Zou W: The LPI/GPR55 axis enhances human breast cancer cell migration via HBXIP and p-MLC signaling. Acta Pharmacol Sin 2018; 39: 459–471.
26.
Romero-Zerbo SY, Ruz-Maldonado I, Espinosa-Jimenez V, Rafacho A, Gomez-Conde AI, Sanchez-Salido L, Cobo-Vuilleumier N, Gauthier BR, Tinahones FJ, Persaud SJ, Bermudez-Silva FJ: The cannabinoid ligand LH-21 reduces anxiety and improves glucose handling in diet-induced obese pre-diabetic mice. Sci Rep 2017; 7: 3946.
27.
Drzazga A, Kristinsson H, Salaga M, Zatorski H, Koziolkiewicz M, Gendaszewska-Darmach E, Bergsten P: Lysophosphatidylcholine and its phosphorothioate analogues potentiate insulin secretion via GPR40 (FFAR1), GPR55 and GPR119 receptors in a different manner. Mol Cell Endocrinol 2018; 472: 117–125.
28.
Drzazga A, Sowinska A, Krzeminska A, Rytczak P, Koziolkiewicz M, Gendaszewska-Darmach E: Lysophosphatidylcholine elicits intracellular calcium signaling in a GPR55-dependent manner. Biochem Biophys Res Commun 2017; 489: 242–247.
29.
Console-Bram L, Ciuciu SM, Zhao P, Zipkin RE, Brailoiu E, Abood ME: N-arachidonoyl glycine, another endogenous agonist of GPR55. Biochem Biophys Res Commun 2017; 490: 1389–1393.
30.
Devinsky O, Cross JH, Laux L, Marsh E, Miller I, Nabbout R, Scheffer IE, Thiele EA, Wright S, Cannabidiol in Dravet Syndrome Study G: Trial of cannabidiol for drug-resistant seizures in the Dravet syndrome. N Engl J Med 2017; 376: 2011–2020.
31.
Devinsky O, Marsh E, Friedman D, Thiele E, Laux L, Sullivan J, Miller I, Flamini R, Wilfong A, Filloux F, Wong M, Tilton N, Bruno P, Bluvstein J, Hedlund J, Kamens R, Maclean J, Nangia S, Singhal NS, Wilson CA, Patel A, Cilio MR: Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trial. Lancet Neurol 2016; 15: 270–278.
32.
Devinsky O, Cross JH, Wright S: Trial of cannabidiol for drug-resistant seizures in the Dravet syndrome. N Engl J Med 2017; 377: 699–700.
33.
Kaplan JS, Stella N, Catterall WA, Westenbroek RE: Cannabidiol attenuates seizures and social deficits in a mouse model of Dravet syndrome. Proc Natl Acad Sci U S A 2017; 114: 11229–11234.
34.
Brown AJ, Daniels DA, Kassim M, Brown S, Haslam CP, Terrell VR, Brown J, Nichols PL, Staton PC, Wise A, Dowell SJ: Pharmacology of GPR55 in yeast and identification of GSK494581A as a mixed-activity glycine transporter subtype 1 inhibitor and GPR55 agonist. J Pharmacol Exp Ther 2011; 337: 236–246.
35.
Mumberg D, Muller R, Funk M: Yeast vectors for the controlled expression of heterologous proteins in different genetic backgrounds. Gene 1995; 156: 119–122.
36.
Kaumann AJ: Blockade of human atrial 5-HT4 receptors by GR113808. Br J Pharmacol 1993; 110: 1172–1174.
37.
Cheng Y, Prusoff WH: Relationship between the inhibition constant (K1) and the concentration of inhibitor which causes 50 per cent inhibition (I50) of an enzymatic reaction. Biochem Pharmacol 1973; 22: 3099–3108.
38.
Heynen-Genel S, Dahl R, Shi S, Milan L, Hariharan S, Bravo Y, Sergienko E, Hedrick M, Dad S, Stonich D, Su Y, Vicchiarelli M, Mangravita-Novo A, Smith LH, Chung TDY, Sharir H, Barak LS, Abood ME: Screening for selective ligands for GPR55 – agonists; Probe reports from the NIH molecular libraries program. Bethesda (MD), 2010
39.
Kotsikorou E, Madrigal KE, Hurst DP, Sharir H, Lynch DL, Heynen-Genel S, Milan LB, Chung TD, Seltzman HH, Bai Y, Caron MG, Barak L, Abood ME, Reggio PH: Identification of the GPR55 agonist binding site using a novel set of high-potency GPR55 selective ligands. Biochemistry 2011; 50: 5633–5647.
40.
Henstridge CM, Balenga NA, Ford LA, Ross RA, Waldhoer M, Irving AJ: The GPR55 ligand L-alpha-lysophosphatidylinositol promotes RhoA-dependent Ca2+ signaling and NFAT activation. FASEB J 2009; 23: 183–193.
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