P2X7 receptor-mediated release of microglial prostanoids and miRNAs correlates with reversal of neuropathic hypersensitivity in rats.

Background: P2X7 receptor antagonists have potential for treating various central nervous system (CNS) diseases, including neuropathic pain, although none have been approved for clinical use. Reasons may include insufficient understanding of P2X7 receptor signalling in pain, and the lack of a corresponding preclinical mechanistic biomarker.

Methods: Lu AF27139 is a highly selective and potent small molecule antagonist at rat, mouse and human forms of the P2X7 receptor, with excellent pharmacokinetic and CNS permeability properties.

Synthesis and Characterization of the Novel Rodent-Active and CNS-Penetrant P2X7 Receptor Antagonist Lu AF27139.

There remains an insufficient number of P2X7 receptor antagonists with adequate rodent potency, CNS permeability, and pharmacokinetic properties from which to evaluate CNS disease hypotheses preclinically. Herein, we describe the molecular pharmacology, safety, pharmacokinetics, and functional CNS target engagement of Lu AF27139, a novel rodent-active and CNS-penetrant P2X7 receptor antagonist. Lu AF27139 is highly selective and potent against rat, mouse, and human forms of the receptors.

Quantitative analysis of lipids: a higher-throughput LC-MS/MS-based method and its comparison to ELISA.

Aim: Lipids such as prostaglandins, leukotrienes and thromboxanes are released as a result of an inflammatory episode in pain (central and peripheral).

Methodology & Results: To measure these lipids as potential mechanistic biomarkers in neuropathic pain models, we developed a higher-throughput LC-MS/MS-based method with simultaneous detection of PGE2, PGD2, PGF2α, LTB4, TXB2 and 2-arachidonoyl glycerol in brain and spinal cord tissues. We also demonstrate that the LC-MS/MS method was more sensitive and specific in differentiating PGE2 levels in CNS tissues compared with ELISA.

Inhibition of the potassium channel K3.1 by senicapoc reverses tactile allodynia in rats with peripheral nerve injury.

Neuropathic pain is a debilitating, chronic condition with a significant unmet need for effective treatment options. Recent studies have demonstrated that in addition to neurons, non-neuronal cells such as microglia contribute to the initiation and maintenance of allodynia in rodent models of neuropathic pain. The Ca- activated K channel, K3.

In vitro differentiation of dendritic cells in the presence of prostaglandin E2 alters the IL-12/IL-23 balance and promotes differentiation of Th17 cells.

PGE2, an endogenous lipid mediator released in inflammatory conditions, affects both dendritic cell (DC) differentiation and maturation. Whereas the effect of PGE2 on fully differentiated DC was studied extensively, little is known about its effects on DC differentiation. In this study, we show that bone marrow-derived DC generated in the presence of PGE2 (DCp) acquire a proinflammatory profile; produce higher levels of proinflammatory cytokines/chemokines; express higher levels of MHC class II, costimulatory molecules, and TLRs; and exhibit increased activation of the NF-kappaB-signaling pathway.

PGE2-induced metalloproteinase-9 is essential for dendritic cell migration.

Following antigen acquisition and maturation, dendritic cells (DCs) disengage from the extracellular matrix, cross basement membranes, and travel to draining lymph nodes to activate T cells. CCR7 expression is necessary but not sufficient for the directional migration of DCs. Prostaglandin E2 (PGE2), present in inflammatory sites, induces DC migration, presumably by enacting a migration-permissive gene expression program.

Prostaglandin E2 exacerbates collagen-induced arthritis in mice through the inflammatory interleukin-23/interleukin-17 axis.

Objective: Recently, Th17 cells, a new subset of CD4+ T cells, emerged as major players in inflammation/autoimmunity. Maintenance of the Th17 phenotype requires interleukin-23 (IL-23), whereas the Th1-promoting cytokine IL-12p70 exerts a negative effect on Th17 cell differentiation. The lipid mediator prostaglandin E(2) (PGE(2)) acts primarily as a proinflammatory agent in autoimmune conditions, through mechanisms that remain to be elucidated.

The proinflammatory effect of prostaglandin E2 in experimental inflammatory bowel disease is mediated through the IL-23-->IL-17 axis.

Although Crohn's disease has been traditionally considered to be Th1-mediated, the newly identified Th17 cells emerged recently as crucial participants. Th1/Th17 differentiation is controlled primarily by the IL-12 family of cytokines secreted by activated dendritic cells (DCs) and macrophages. IL-23 and IL-12/IL-27 have opposite effects, supporting the Th17 and Th1 phenotypes, respectively.