RESUMO
Neuropathic pain is a form of chronic pain that develops because of damage to the nervous system. Treatment of neuropathic pain is often incompletely effective, and most available therapeutics have only moderate efficacy and present side effects that limit their use. Opioids are commonly prescribed for the management of neuropathic pain despite equivocal results in clinical studies and significant abuse potential. Thus, neuropathic pain represents an area of critical unmet medical and novel classes of therapeutics with improved efficacy and safety profiles are urgently needed. The cannabidiol (CBD) structural analogue and novel antagonist of GPR55, KLS-13019, was screened in rat models of neuropathic pain. Tactile sensitivity associated with chemotherapy exposure was induced in rats with once daily 1mg/kg paclitaxel injections for 4 days or 5 mg/kg oxaliplatin every third day for one week. Rats were then administered KLS-13019 or comparator drugs on day 7 in an acute dosing paradigm or days 7-10 in a chronic dosing paradigm and mechanical or cold allodynia was assessed. Allodynia was reversed in a dose-dependent manner in the rats treated with KLS-13019, with the highest dose reverting the response to pre-paclitaxel injection baseline levels with both I.P. and P.O. administration after acute dosing. In the chronic dosing paradigm, 4 consecutive doses of KLS-13019 completely reversed allodynia for the duration of the phenotype in control animals. Additionally, co-administration of KLS -13019 with paclitaxel prevented the allodynic phenotype from developing. Together, these data suggest that KLS-13019 represents a potential new drug for the treatment of neuropathic pain. Significance Statement Chemotherapy-induced neuropathic pain (CIPN) is a common, debilitating side effect of cancer treatment with no known cure. GPR55 antagonist KLS-13019 represents a novel class of drug for this condition that is a potent, durable inhibitor of allodynia associated with CIPN in rats in both prevention and reversal dosing paradigms. This novel therapeutic approach addresses a critical area of unmet medical need.
RESUMO
GPCRs have diverse signaling capabilities, based on their ability to assume various conformations. Moreover, it is now appreciated that certain ligands can promote distinct receptor conformations and thereby bias signaling toward a specific pathway to differentially affect cell function. The recently deorphanized G protein-coupled receptor OGR1 [ovarian cancer G protein-coupled receptor 1 ( GPR68)] exhibits diverse signaling events when stimulated by reductions in extracellular pH. We recently demonstrated airway smooth muscle cells transduce multiple signaling events, reflecting a diverse capacity to couple to multiple G proteins. Moreover, we recently discovered that the benzodiazepine lorazepam, more commonly recognized as an agonist of the γ-aminobutyric acid A (GABAA) receptor, can function as an allosteric modulator of OGR1 and, similarly, can promote multiple signaling events. In this study, we demonstrated that different benzodiazepines exhibit a range of biases for OGR1, with sulazepam selectively activating the canonical Gs of the G protein signaling pathway, in heterologous expression systems, as well as in several primary cell types. These findings highlight the potential power of biased ligand pharmacology for manipulating receptor signaling qualitatively, to preferentially activate pathways that are therapeutically beneficial.-Pera, T., Deshpande, D. A., Ippolito, M., Wang, B., Gavrila, A., Michael, J. V., Nayak, A. P., Tompkins, E., Farrell, E., Kroeze, W. K., Roth, B. L., Panettieri, R. A. Jr Benovic, J. L., An, S. S., Dulin, N. O., Penn, R. B. Biased signaling of the proton-sensing receptor OGR1 by benzodiazepines.