Anti-inflammatory activity of cannabinoid receptor 2 ligands in primary hPDL fibroblasts.

OBJECTIVES: Approximately 65 million adults in the US have periodontitis, causing tooth loss and decreased quality of life. Cannabinoids modulate immune responses, and endocannabinoids are prevalent during oral cavity inflammation. Targets for intervention in periodontal inflammation are cannabinoid type 1 and 2 receptors (CB1R, CB2R), particularly CB2R because its levels increase during inflammation. We previously demonstrated that SMM-189 (CB2R inverse agonist) decreased pro-inflammatory cytokine production in primary microglial cells. The hypothesis of this study was that cannabinoids anandamide (AEA), HU-308 (CB2R selective agonist), and SMM-189 decrease pro-inflammatory IL-6 and MCP-1 production by primary human periodontal ligament fibroblasts (hPDLFs) stimulated with P. gingivalis LPS, TNF-α, or IL-1ß. DESIGN: Cytotoxic effects of cannabinoid compounds (10-4-10-6.5 M), LPS (1-1000 ng/ml), TNFα (10 ng/ml) and IL-1ß (1 ng/ml) were assessed by measuring effects on cellular dehydrogenase activity. IL-6 and MCP-1 production were measured using Mesoscale Discovery (MSD) Human Pro-Inflammatory IL-6 and MSD Human Chemokine MCP-1 kits and analyzed using MSD Sector 2400 machine. RESULTS: EC50 values for AEA, SMM-189, and HU-308 were 16 µM, 13 µM, and 7.3 µM respectively. LPS (1 µg/ml), TNF-α (10 ng/ml), and IL-1ß (1 ng/ml) increased IL-6 and MCP-1 production, which were inhibited by AEA, SMM-189, and HU-308. AEA alone significantly increased IL-6, but not MCP-1 levels, but the other cannabinoids alone had no effect. CONCLUSION: The effective inhibition of LPS, TNF-α, IL-1ß stimulated IL-6 and MCP-1 production by CB2R ligands in hPDLFs suggests that targeting the endocannabinoid system may lead to development of novel drugs for periodontal therapy, aiding strategies to improve oral health.

Optimization of cAMP fluorescence dataset from ACTOne cannabinoid receptor 1 cell line.

The ACTOne cannabinoid receptor 1 functional system is comprised of transfected HEK cells with the parental cyclic nucleotide gated channel (CNG) co-transfected with cannabinoid receptor 1 (CB1). The ACTOne CB1 cell line was evaluated for cAMP driven fluorescence by optimizing experimental conditions for sensitivity to forskolin and CP 55,940, reading time point, reliability of cell passage number, and pertussis inactivation of Gi/o.

Cannabinoid receptor 1 ligands revisited: Pharmacological assessment in the ACTOne system.

In vitro cannabinoid pharmacology has evolved over time from simple receptor binding to include [(35)S]GTPγ, ß-arrestin, and cAMP assays. Each assay has benefits and drawbacks; however, no single functional system has been used for high-throughput evaluation of compounds from binding to pharmacological functionality and antagonist assessment in a well-characterized human cell line. In this study, we evaluated and validated one system-ACTOne human embryonic kidney cells transfected with a cyclic nucleotide gated channel and cannabinoid receptor 1 (CB1)-and compared human CB1 affinity, functional, and antagonistic effects on cAMP with previously published results. The study was conducted on a diverse group of CB1 ligands, including endocannabinoids and related compounds, 2-AG, AEA, MAEA, and ACEA, the phytocannabinoid Δ(9) THC, and synthetic cannabinoids CP 55,940, WIN 55,212-2, SR 141716A, CP 945,598, and WIN 55,212-3. Our results were compared with literature values where human CB1 was used for affinity determination and cAMP was used as a functional readout. Here we report the first detailed evaluation of the ACTOne assay for the pharmacological evaluation of CB1 ligands. The results from the study reveal some interesting deviations from previously reported functional activities of the aforementioned ligands.

Synthesis and biological evaluation of (3',5'-dichloro-2,6-dihydroxy-biphenyl-4-yl)-aryl/alkyl-methanone selective CB2 inverse agonist.

Cannabinoid receptor 2 (CB2) selective agonists and inverse agonists possess significant potential as therapeutic agents for regulating inflammation and immune function. Although CB2 agonists have received the greatest attention, it is emerging that inverse agonists also manifest anti-inflammatory activity. In process of designing new cannabinoid ligands we discovered that the 2,6-dihydroxy-biphenyl-aryl methanone scaffold imparts inverse agonist activity at CB2 receptor without functional activity at CB1. To further explore the scaffold we synthesized a series of (3',5'-dichloro-2,6-dihydroxy-biphenyl-4-yl)-aryl/alkyl-methanone analogs and evaluated the CB1 and CB2 affinity, potency, and efficacy. The studies reveal that an aromatic C ring is required for inverse agonist activity and that substitution at the 4 position is optimum. The resorcinol moiety is required for optimum CB2 inverse agonist activity and selectivity. Antagonist studies against CP 55,940 demonstrate that the compounds 41 and 45 are noncompetitive antagonists at CB2.

Motor, visual and emotional deficits in mice after closed-head mild traumatic brain injury are alleviated by the novel CB2 inverse agonist SMM-189.

We have developed a focal blast model of closed-head mild traumatic brain injury (TBI) in mice. As true for individuals that have experienced mild TBI, mice subjected to 50-60 psi blast show motor, visual and emotional deficits, diffuse axonal injury and microglial activation, but no overt neuron loss. Because microglial activation can worsen brain damage after a concussive event and because microglia can be modulated by their cannabinoid type 2 receptors (CB2), we evaluated the effectiveness of the novel CB2 receptor inverse agonist SMM-189 in altering microglial activation and mitigating deficits after mild TBI. In vitro analysis indicated that SMM-189 converted human microglia from the pro-inflammatory M1 phenotype to the pro-healing M2 phenotype. Studies in mice showed that daily administration of SMM-189 for two weeks beginning shortly after blast greatly reduced the motor, visual, and emotional deficits otherwise evident after 50-60 psi blasts, and prevented brain injury that may contribute to these deficits. Our results suggest that treatment with the CB2 inverse agonist SMM-189 after a mild TBI event can reduce its adverse consequences by beneficially modulating microglial activation. These findings recommend further evaluation of CB2 inverse agonists as a novel therapeutic approach for treating mild TBI.

Physiological and pharmacokinetic effects of oral 1,3-dimethylamylamine administration in men.

BACKGROUND: 1,3-dimethylamylamine (DMAA) has been a component of dietary supplements and is also used within "party pills," often in conjunction with alcohol and other drugs. Ingestion of higher than recommended doses results in untoward effects including cerebral hemorrhage. To our knowledge, no studies have been conducted to determine both the pharmacokinetic profile and physiologic responses of DMAA. METHODS: Eight men reported to the lab in the morning following an overnight fast and received a single 25 mg oral dose of DMAA. Blood samples were collected before and through 24 hours post-DMAA ingestion and analyzed for plasma DMAA concentration using high-performance liquid chromatography-mass spectrometry. Resting heart rate, blood pressure, and body temperature was also measured. RESULTS: One subject was excluded from the data analysis due to abnormal DMAA levels. Analysis of the remaining seven participants showed DMAA had an oral clearance of 20.02 ± 5 L∙hr⁻¹, an oral volume of distribution of 236 ± 38 L, and terminal half-life of 8.45 ± 1.9 hr. Lag time, the delay in appearance of DMAA in the circulation following extravascular administration, varied among participants but averaged approximately 8 minutes (0.14 ± 0.13 hr). The peak DMAA concentration for all subjects was observed within 3-5 hours following ingestion and was very similar across subjects, with a mean of ~70 ng∙mL⁻¹. Heart rate, blood pressure, and body temperature were largely unaffected by DMAA treatment. CONCLUSIONS: These are the first data to characterize the oral pharmacokinetic profile of DMAA. These findings indicate a consistent pattern of increase across subjects with regards to peak DMAA concentration, with peak values approximately 15-30 times lower than those reported in case studies linking DMAA intake with adverse events. Finally, a single 25 mg dose of DMAA does not meaningfully impact resting heart rate, blood pressure, or body temperature. TRIAL REGISTRATION: NCT01765933.

Preclinical pharmacokinetics of the radiomitigator KZ-41 in rats.

KZ-41, a quinic acid derivative, significantly reduces mortality in a murine model of hematopoietic acute radiation syndrome. The purpose of this study was to evaluate the systemic pharmacokinetics, elimination, and oral bioavailability of KZ-41 in rats. Male Sprague-Dawley rats (n = 6 per group) received a single dose (10 mg/kg) of KZ-41 administered either intravenously via the jugular vein or orally via gavage. In vitro stability was determined using both rat liver microsomes and the bacteria Gluconobacter oxydans. KZ-41 concentrations were determined using LC-MS/MS (liquid chromatography tandom mass spectrometry). Half-life of KZ-41 was ≈3 hr after either intravenous or oral administration. Mean volume of distribution was 3.3 L/kg. Extent of absorption (F) after oral administration was estimated to be ~100%, which was consistent with the finding that KZ-41 was stable to liver microsomal and bacterial degradation. Following intravenous administration, KZ-41 demonstrated a medium clearance and volume of distribution with a terminal half-life of ≈3 hr. KZ-41 was rapidly and completely absorbed (F ≅ 1), which was consistent with the findings that KZ-41 is resistant to presystemic elimination mechanisms (i.e. enteric bacterial degradation and hepatic metabolism). Thus, KZ-41 represents an excellent candidate for further development as an orally available agent for the mitigation of radiation injury.