Eyes open to stem cells: safety trial may pave the way for cell therapy to treat retinal disease in patients

A clinical trial using human embryonic stem cell (hESC) therapy for an inherited retinal degenerative disease is about to commence. The Advanced Cell Technology (ACT) trial will treat patients with Stargardt's macular dystrophy using transplanted retinal pigment epithelium derived from hESCs. Currently, no effective treatment is available for Stargardt's disease so a stem cell-based therapy that can slow progression of this blinding condition could represent a significant breakthrough. While there are some hurdles to clear, the ACT trial is a fine example of translational research that could eventually pave the way for a range of stem cell therapies for the retina and other tissues.

Protection of cattle against a natural infection of Fasciola hepatica by vaccination with recombinant cathepsin L1 (rFhCL1)

The liver fluke, Fasciola hepatica causes liver fluke disease, or fasciolosis, in ruminants such as cattle and sheep. An effective vaccine against the helminth parasite is essential to reduce our reliance on anthelmintics, particularly in light of frequent reports of resistance to some frontline drugs. In our study, Friesian cattle (13 per group) were vaccinated with recombinant F. hepatica cathepsin L1 protease (rFhCL1) formulated in mineral-oil based adjuvants, Montanide (TM) ISA 70VG and ISA 206VG. Following vaccination the animals were exposed to fluke-contaminated pastures for 13 weeks. At slaughter, there was a significant reduction in fluke burden of 48.2% in the cattle in both vaccinated groups, relative to the control non-vaccinated group, at p

Evaluation of hepatic changes and local and systemic immune responses in goats immunized with recombinant Peroxiredoxin (Prx) and challenged with Fasciola hepatica

Protection against Fasciola hepatica in goats immunized with Peroxiredoxin (Prx) was assessed. The experimental trial consisted of three groups of seven animals: group 1 were unimmunized and uninfected, group 2 were immunized with adjuvant only and group 3 were immunized with recombinant Prx in adjuvant (immunized and infected). Immunization with Prx in Quil A adjuvant, group 3, induced a reduction in fluke burden of 33.04% when compared to adjuvant control, group 2, although this difference was not significant. The hepatic gross and microscopical morphometric study revealed lower damage in the Prx-immunized compared to group 2 (p

Connected Life Courses:Influences on and Experiences of 'Midlife' In-Migration to Rural Areas

This paper aims to contribute to the theorisation of midlife migration into rural areas. Although the factors influencing migration are known to be variable at different stages of a person's life, much less well understood is how migration decisions at different stages of the life course are connected and how post-migration experiences may be influenced by an earlier life course stage. We argue that midlife migration decisions are the product of the migrant's lifetime experiences and influences up until that stage in their life alongside their expectations and aspirations for future life course stages. Using a case study of the Glens of Antrim (Northern Ireland), this paper specifically demonstrates the role of childhood memories to explain midlife migration to a rural area. In doing so, it argues that some findings more commonly associated with second-generation transnational migration are also equally relevant to migration within the UK. Roots migration and place attachment alongside the midlife migrant's post-migration sense of belonging and permanency are found to be influenced by the migrant's earlier memories, behaviours, and experiences.

Discovery of Novel Allosteric Modulators of Metabotropic Glutamate Receptor Subtype 5 Reveals Chemical and Functional Diversity and In Vivo Activity in Rat Behavioral Models of Anxiolytic and Antipsychotic Activity

Modulators of metabotropic glutamate receptor subtype 5 (mGluR5) may provide novel treatments for multiple central nervous system (CNS) disorders, including anxiety and schizophrenia. Although compounds have been developed to better understand the physiological roles of mGluR5 and potential usefulness for the treatment of these disorders, there are limitations in the tools available, including poor selectivity, low potency, and limited solubility. To address these issues, we developed an innovative assay that allows simultaneous screening for mGluR5 agonists, antagonists, and potentiators. We identified multiple scaffolds that possess diverse modes of activity at mGluR5, including both positive and negative allosteric modulators (PAMs and NAMs, respectively). 3-Fluoro-5-(3-(pyridine-2-yl)-1,2,4-oxadiazol-5-yl) benzonitrile (VU0285683) was developed as a novel selective mGluR5 NAM with high affinity for the 2-methyl-6-(phenyl-ethynyl)-pyridine (MPEP) binding site. VU0285683 had anxiolytic-like activity in two rodent models for anxiety but did not potentiate phen-cyclidine-induced hyperlocomotor activity. (4-Hydroxypiperidin-1-yl)(4-phenylethynyl) phenyl) methanone (VU0092273) was identified as a novel mGluR5 PAM that also binds to the MPEP site. VU0092273 was chemically optimized to an orally active analog, N-cyclobutyl-6-((3-fluorophenyl) ethynyl) nicotinamide hydrochloride (VU0360172), which is selective for mGluR5. This novel mGluR5 PAM produced a dose-dependent reversal of amphetamine-induced hyperlocomotion, a rodent model predictive of antipsychotic activity. Discovery of structurally and functionally diverse allosteric modulators of mGluR5 that demonstrate in vivo efficacy in rodent models of anxiety and antipsychotic activity provide further support for the tremendous diversity of chemical scaffolds and modes of efficacy of mGluR5 ligands. In addition, these studies provide strong support for the hypothesis that multiple structurally distinct mGluR5 modulators have robust activity in animal models that predict efficacy in the treatment of CNS disorders.

Synthesis and SAR of novel, non-MPEP chemotype mGluR5 NAMs identified by functional HTS

This Letter describes the discovery and SAR of three novel series of mGluR5 non-competitive antagonists/negative allosteric modulators (NAMs) not based on manipulation of an MPEP/MTEP chemotype identified by a functional HTS approach. This work demonstrates fundamentally new mGluR5 NAM chemotypes with submicromolar potencies, and further examples of a mode of pharmacology 'switch' to provide PAMs with a non-MPEP scaffold. (C) 2009 Elsevier Ltd. All rights reserved.

Synthesis and SAR of a novel positive allosteric modulator (PAM) of the metabotropic glutamate receptor 4 (mGluR4)

This Letter describes the synthesis and SAR of the novel positive allosteric modulator, VU0155041, a compound that has shown in vivo efficacy in rodent models of Parkinson's disease. The synthesis takes advantage of an iterative parallel synthesis approach to rapidly synthesize and evaluate a number of analogs of VU0155041. (C) 2009 Elsevier Ltd. All rights reserved.

A Novel Selective Muscarinic Acetylcholine Receptor Subtype 1 Antagonist Reduces Seizures without Impairing Hippocampus-Dependent Learning

Previous studies suggest that selective antagonists of specific subtypes of muscarinic acetylcholine receptors (mAChRs) may provide a novel approach for the treatment of certain central nervous system (CNS) disorders, including epileptic disorders, Parkinson's disease, and dystonia. Unfortunately, previously reported antagonists are not highly selective for specific mAChR subtypes, making it difficult to definitively establish the functional roles and therapeutic potential for individual subtypes of this receptor subfamily. The M 1 mAChR is of particular interest as a potential target for treatment of CNS disorders. We now report the discovery of a novel selective antagonist of M-1 mAChRs, termed VU0255035 [N-(3-oxo-3-(4-(pyridine-4-yl)piperazin-1-yl)propyl)benzo[c][1,2,5]thiadiazole-4-sulfonamide]. Equilibrium radioligand binding and functional studies demonstrate a greater than 75-fold selectivity of VU0255035 for M-1 mAChRs relative to M-2-M-5. Molecular pharmacology and mutagenesis studies indicate that VU0255035 is a competitive orthosteric antagonist of M-1 mAChRs, a surprising finding given the high level of M-1 mAChR selectivity relative to other orthosteric antagonists. Whole-cell patch-clamp recordings demonstrate that VU0255035 inhibits potentiation of N-methyl-D-aspartate receptor currents by the muscarinic agonist carbachol in hippocampal pyramidal cells. VU0255035 has excellent brain penetration in vivo and is efficacious in reducing pilocarpine-induced seizures in mice. We were surprised to find that doses of VU0255035 that reduce pilo-carpine-induced seizures do not induce deficits in contextual freezing, a measure of hippocampus-dependent learning that is disrupted by nonselective mAChR antagonists. Taken together, these data suggest that selective antagonists of M-1 mAChRs do not induce the severe cognitive deficits seen with nonselective mAChR antagonists and could provide a novel approach for the treatment certain of CNS disorders.

Positive allosteric modulators of the metabotropic glutamate receptor subtype 4 (mGluR4). Part II: Challenges in hit-to-lead

This Letter describes the synthesis and SAR of two mGluR4 positive allosteric modulator leads, 6 and 7. VU001171 (6) represents the most potent (EC50 = 650 nM), efficacious (141% Glu Max) and largest fold shift (36-fold) of any mGluR4 PAM reported to date. However, this work highlights the challenges in hit-to-lead for mGluR4 PAMs, with multiple confirmed HTS hits displaying little or no tractable SAR. (C) 2008 Elsevier Ltd. All rights reserved.

Design of potent GlyT1 inhibitors: In vitro and in vivo profiles

Inhibitors of Gly transporter type-1 (GlyT1) for the treatment of schizophrenia have been pursued on the basis of the NMDA receptor (R) hypofunction hypothesis, which stems largely from the observation that NMDAR antagonists induce symptoms that more closely mimic those characteristic of schizophrenia than do other classes of psychotic agents. GlyT1 is responsible for uptake of synaptic Gly, an NMDAR co-agonist amino acid, in neuronal populations throughout the forebrain. GlyT1 inhibition thereby potentiates NMDAR activity by increasing synaptic Gly levels. Correspondingly, a large body of data suggests that GlyT1 inhibitors likely confer more comprehensive symptom alleviation than current antipsychotics. To date, a number of small-molecule GlyT1 inhibitors have been reported by the pharmaceutical industry. Developments in the discovery and characterization of GlyT1 inhibitors are discussed in this review.

Context-Dependent Pharmacology Exhibited by Negative Allosteric Modulators of Metabotropic Glutamate Receptor 7

Phenotypic studies of mice lacking metabotropic glutamate receptor subtype 7 (mGluR7) suggest that antagonists of this receptor may be promising for the treatment of central nervous system disorders such as anxiety and depression. Suzuki et al. (J Pharmacol Exp Ther 323: 147-156, 2007) recently reported the in vitro characterization of a novel mGluR7 antagonist called 6-(4-methoxyphenyl)-5-methyl-3-(4-pyridinyl)-isoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP), which noncompetitively inhibited the activity of orthosteric and allosteric agonists at mGluR7. We describe that MMPIP acts as a noncompetitive antagonist in calcium mobilization assays in cells coexpressing mGluR7 and the promiscuous G protein G alpha(15). Assessment of the activity of a small library of MMPIP-derived compounds using this assay reveals that, despite similar potencies, compounds exhibit differences in negative co-operativity for agonist-mediated calcium mobilization. Examination of the inhibitory activity of MMPIP and analogs using endogenous G(i/o)-coupled assay readouts indicates that the pharmacology of these ligands seems to be context-dependent, and MMPIP exhibits differences in negative cooperativity in certain cellular backgrounds. Electrophysiological studies reveal that, in contrast to the orthosteric antagonist (2S)-2-amino-2-[(1S,2S)-2-carboxyclycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY341495), MMPIP is unable to block agonist-mediated responses at the Schaffer collateral-CA1 synapse, a location at which neurotransmission has been shown to be modulated by mGluR7 activity. Thus, MMPIP and related compounds differentially inhibit coupling of mGluR7 in different cellular backgrounds and may not antagonize the coupling of this receptor to native G(i/o) signaling pathways in all cellular contexts. The pharmacology of this compound represents a striking example of the potential for context-dependent blockade of receptor responses by negative allosteric modulators.

Synthesis and SAR of novel, 4-(phenylsulfamoyl)phenylacetamide mGlu(4) positive allosteric modulators (PAMs) identified by functional high-throughput screening (HTS)

Herein we disclose the synthesis and SAR of a series of 4-(phenylsulfamoyl)phenylacetamide compounds as mGlu(4) positive allosteric modulators (PAMs) that were identified via a functional HTS. An iterative parallel approach to these compounds culminated in the discovery of VU0364439 (11) which represents the most potent (19.8 nM) mGlu(4) PAM reported to date. (C) 2010 Elsevier Ltd. All rights reserved.