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.

Chemical biology of mGlu4 receptor activation: dogmas, challenges, strategies and opportunities.

Drug design necessitates a clear understanding of the phenotypic response to be elicited by a given ligandtarget interaction. This relationship is relatively well understood for classical biological targets of drug action, but for some novel targets, notably those amenable to allosteric modulation, developing such understanding may represent a more challenging task. In order to gain knowledge on the nature of the functional response derived from mGlu4 receptor activation, its molecular and cell biology are reviewed, including signalling pathways involved, receptor localization in central nervous system and beyond, and potential genetic links to disease.

Fused thiazolyl alkynes as potent mGlu5 receptor positive allosteric modulators.

A new series of potent fused thiazole mGlu5 receptor positive allosteric modulators (PAMs) (10, 11 and 27-31) are disclosed and details of the SAR and optimization are described. Optimization of alkynyl thiazole 9 (Lu AF11205) led to the identification of potent fused thiazole analogs 10b, 27a, 28j and 31d. In general, substituted cycloalkyl, aryl and heteroaryl carboxamides, and carbamate analogs are mGlu5PAMs, whereas smaller alkyl carboxamide, sulfonamide and sulfamide analogs tend to be mGlu5 negative allosteric modulators (NAMs).

Discovery and structure-activity relationship of 1,3-cyclohexyl amide derivatives as novel mGluR5 negative allosteric modulators.

A novel series of trans-1,3-cyclohexyl diamides was discovered and characterized as mGluR5 negative allosteric modulators (NAMs) lacking an alkyne moiety. Conformational constraint of one of the amide bonds in the diamide template led to a spirooxazoline template. A representative compound (24d) showed good in vitro potency, high CNS penetration and, upon subcutaneous dosing, demonstrated efficacy in the mouse marble burying test, generally used as indicative of potential anxiolytic activity.

Azetidinyl oxadiazoles as potent mGluR5 positive allosteric modulators.

A novel series of aryl azetidinyl oxadiazoles are identified as mGluR5 positive allosteric modulators (PAMs) with improved physico-chemical properties. N-substituted cyclohexyl and exo-norbornyl carboxamides, and carbamate analogs of azetidines are moderate to potent mGluR5 PAMs. The aryl, lower alkyl carboxamides analogs and sulfonamide analogs of azetidines are moderate mGluR5 negative allosteric modulators (NAMs).

N-Aryl pyrrolidinonyl oxadiazoles as potent mGluR5 positive allosteric modulators.

A novel series of N-aryl pyrrolidinonyl oxadiazoles were identified as mGluR5 positive allosteric modulators (PAMs). Optimization of the initial lead compound 6a led to the identification of the 12c (-) enantiomer as a potent compound with acceptable in vitro clearance, CYP, hERG and PK properties. Para substituted N-aryl pyrrolidinonyl oxadiazoles are mGluR5 PAMs while the meta and ortho substituted N-aryl pyrrolidinonyl oxadiazoles are negative allosteric modulators (NAMs).

Efficacy switching SAR of mGluR5 allosteric modulators: highly potent positive and negative modulators from one chemotype.

A series of metabotropic glutamate 5 receptor (mGluR5) allosteric ligands with positive, negative or no modulatory efficacy is described. The ability of this series to yield both mGluR5 PAMs and NAMs with single-digit nanomolar potency is unusual, and the underlying SAR is detailed.

Novel heterocyclic compounds as mGlu5 antagonists: WO2009015897.

Metabotropic glutamate receptor 5 (mGlu5) negative allosteric modulators (NAMs) have previously been implicated in a number of pathophysiological conditions, based on preclinical, and to some extent clinical, proof of concept for migraine, gastroesophageal reflux disease, Parkinson's disease and anxiety. In the past, the potential use of known mGlu5 antagonists for the treatment of lower urinary tract disorders was disclosed. In the patent evaluated herein, novel derivatives of 4-(prop-2-ynylidene)piperidine are described and claimed by Recordati Ireland Ltd, Ireland, as NAMs at mGlu5 for the treatment of lower urinary tract disorders.

Discovery of a potent and brain penetrant mGluR5 positive allosteric modulator.

This Letter describes the discovery of a novel series of mGluR5 positive allosteric modulators (PAMs). The lead compound, 11c, exhibits excellent potency (EC(50)=30 nM) in vitro, and reaches high brain levels in both rats and mice after oral administration.

Identification and characterization of NDT 9513727 [N,N-bis(1,3-benzodioxol-5-ylmethyl)-1-butyl-2,4-diphenyl-1H-imidazole-5-methanamine], a novel, orally bioavailable C5a receptor inverse agonist.

The complement system represents an innate immune mechanism of host defense that has three effector arms, the C3a receptor, the C5a receptor (C5aR), and the membrane attack complex. Because of its inflammatory and immune-enhancing properties, the biological activity of C5a and its classical receptor have been widely studied. Because specific antagonism of the C5aR could have therapeutic benefit without affecting the protective immune response, the C5aR continues to be a promising target for pharmaceutical research.

Aminopyrazine CB1 receptor inverse agonists.

A series of 5,6-diaryl-2-amino-pyrazines were prepared and found to have antagonist-like properties at the CB1 receptor. Subsequent SAR studies optimized both receptor potency and drug-like properties including solubility and Cytochrome-P450 inhibition potential. Optimized compounds were demonstrated to be inverse agonists and compared in vivo with rimonabant for their ability to inhibit food intake, to occupy central CB1 receptors and to influence hormonal markers associated with obesity.

Leukocyte effects of C5a-receptor blockade during simulated extracorporeal circulation.

Background: Distinct pathways of leukocyte activation during simulated cardiopulmonary bypass are mediated by the complement C5a anaphylatoxin. We hypothesized that a human C5a receptor antagonist would specifically inhibit the inflammatory response of neutrophils to simulated extracorporeal circulation, while preserving the C5b-9 pathway for innate immunity.

Methods: An in vitro extracorporeal circuit recirculated fresh heparinized whole blood through a membrane oxygenator with and without addition of a small molecule human C5a receptor antagonist.

Molecular characterization of the gerbil C5a receptor and identification of a transmembrane domain V amino acid that is crucial for small molecule antagonist interaction.

Anaphylatoxin C5a is a potent inflammatory mediator associated with pathogenesis and progression of several inflammation-associated disorders. Small molecule C5a receptor (C5aR) antagonist development is hampered by species-specific receptor biology and the associated inability to use standard rat and mouse in vivo models. Gerbil is one rodent species reportedly responsive to small molecule C5aR antagonists with human C5aR affinity.

C5L2, a nonsignaling C5A binding protein.

C5a anaphylatoxin, a potent inflammatory mediator, is known to act through a specific G protein coupled receptor. However, some of the complex effects of C5a in vivo may not be explained solely by the deletion of the known receptor. Here, we show that an orphan receptor, identified as C5L2, is a high affinity C5a binding protein.