guanosine-5--o-(3-thiotriphosphate) and Edema

Sphingosine 1-phosphate (S1P) regulates lymphocyte trafficking via type-1 S1P receptor (S1P(1)) and participates in many pathological conditions. We developed a novel type S1P(1)-selective antagonist, TASP0251078, which is structurally unrelated to S1P. This competitive antagonist inhibited binding of S1P to S1P(1) resulting in reduced signaling downstream of S1P(1), including GTPγS-binding and cAMP formation. TASP0251078 also inhibited S1P-induced cellular responses such as chemotaxis and receptor-internalization. Furthermore, when administered in vivo, TASP0251078 induced lymphopenia in blood, which is different from previously reported effects of other S1P(1)-antagonists. In a mouse contact hypersensitivity model, TASP0251078 effectively suppressed ear swelling, leukocyte infiltration, and hyperplasia. These findings provide the chemical evidence that S1P(1) antagonism is responsible for lymphocyte sequestration from the blood, and suggest that the effect of S1P(1) agonists on lymphocyte sequestration results from their functional antagonism.

Topics: Animals; Chemotaxis; CHO Cells; Cricetinae; Cricetulus; Cyclic AMP; Dermatitis, Contact; Ear; Edema; Female; Guanosine 5'-O-(3-Thiotriphosphate); HEK293 Cells; Humans; Hyperplasia; Leukocytes; Lymphopenia; Lysophospholipids; Male; Mice; Mice, Inbred BALB C; Molecular Structure; Protein Binding; Rats; Rats, Inbred Lew; Receptors, Lysosphingolipid; Sphingosine; Sulfonamides; Triazoles

The phytocannabinoid, Delta(9)-tetrahydrocannabivarin (THCV), can block cannabinoid CB(1) receptors. This investigation explored its ability to activate CB(2) receptors, there being evidence that combined CB(2) activation/CB(1) blockade would ameliorate certain disorders.. We tested the ability of THCV to activate CB(2) receptors by determining whether: (i) it inhibited forskolin-stimulated cyclic AMP production by Chinese hamster ovary (CHO) cells transfected with human CB(2) (hCB(2)) receptors; (ii) it stimulated [(35)S]GTPgammaS binding to hCB(2) CHO cell and mouse spleen membranes; (iii) it attenuated signs of inflammation/hyperalgesia induced in mouse hind paws by intraplantar injection of carrageenan or formalin; and (iv) any such anti-inflammatory or anti-hyperalgesic effects were blocked by a CB(1) or CB(2) receptor antagonist.. THCV inhibited cyclic AMP production by hCB(2) CHO cells (EC(50)= 38 nM), but not by hCB(1) or untransfected CHO cells or by hCB(2) CHO cells pre-incubated with pertussis toxin (100 ng.mL(-1)) and stimulated [(35)S]GTPgammaS binding to hCB(2) CHO and mouse spleen membranes. THCV (0.3 or 1 mg.kg(-1) i.p.) decreased carrageenan-induced oedema in a manner that seemed to be CB(2) receptor-mediated and suppressed carrageenan-induced hyperalgesia. THCV (i.p.) also decreased pain behaviour in phase 2 of the formalin test at 1 mg.kg(-1), and in both phases of this test at 5 mg.kg(-1); these effects of THCV appeared to be CB(1) and CB(2) receptor mediated.. THCV can activate CB(2) receptors in vitro and decrease signs of inflammation and inflammatory pain in mice partly via CB(1) and/or CB(2) receptor activation.

Topics: Animals; Cell Line, Transformed; CHO Cells; Cricetinae; Cricetulus; Cyclic AMP; Dose-Response Relationship, Drug; Dronabinol; Edema; Guanosine 5'-O-(3-Thiotriphosphate); Humans; Inflammation; Male; Membranes; Mice; Mice, Inbred C57BL; Pain; Pain Measurement; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Spleen

Work to improve the therapeutic properties of cannabinoid CB(2) receptor-selective inverse agonists has led to the development of Sch.036, an aryl substituted triaryl bis-sulfone with improved oral pharmacokinetic parameters. In this report, we show that this compound blocks in vivo trafficking of various leukocyte populations, a property consistent with other members of this chemical series. This CB(2)-selective compound also shows efficacy in leukocyte recruitment models when added in concert with suboptimal doses of selected anti-inflammatory agents, consistent with its unique function and indicative of its potential therapeutic utility. Finally, studies with Sch.036 show that this cannabinoid CB(2)-specific inverse agonist can ameliorate bone damage in a rat model of relapsing-remitting arthritis. This result suggests that a cannabinoid CB(2)-selective inverse agonist may help ameliorate a particularly harmful property of this inflammatory joint disease.

Topics: Animals; Antigens; Area Under Curve; Arthritis, Experimental; Bone Density Conservation Agents; Bone Resorption; Chemotaxis; Edema; Female; Guanosine 5'-O-(3-Thiotriphosphate); Hypersensitivity, Delayed; Indicators and Reagents; Ligands; Lipopolysaccharides; Mice; Pleurisy; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Sulfones