Senexis Ltd

Cambridge, United Kingdom

Senexis Ltd

Cambridge, United Kingdom
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O'Hare Eugene E.,Queen's University of Belfast | Scopes D.I.C.,Senexis Ltd | Treherne J.M.,Senexis Ltd | Norwood K.,University of Ulster | And 2 more authors.
Behavioural Brain Research | Year: 2010

Clinically accessible compounds that arrest or reverse the effects of amyloid-β (Aβ) on progressively developing behavioural symptomatology and neuropathology in Alzheimer's disease (AD) have yet to become available. However, a viable strategy may be to target and neutralise soluble Aβ oligomers, which have been shown to mediate synaptic dysfunction and to produce cognitive deficits in the intact organism. Inhibiting the aggregation of Aβ is therapeutically attractive, as Aβ aggregation is a pathological event and pharmacological interventions targeting this are likely to have a non-toxic profile. A behavioural assay, the alternating-lever cyclic-ratio schedule, was used to assess the effect of Aβ oligomers and the non-peptide small molecule RS-0406 in male Sprague-Dawley rats. RS-0406 has been shown to inhibit Aβ1-42 fibrillogenesis and protect against Aβ1-42-induced cytotoxicity in primary hippocampal neurons. In the current study, RS-0406 ameliorated the adverse effects of secreted oligomers of human Aβ on behaviour and dose dependently reduced the behavioural effects of Aβ oligomers, with the highest dose, 10μM, maintaining behaviour approximately at control levels. This effect appeared to be central; peripheral confounds having been extensively investigated. This is the first published report on the effects of RS-0406 in vivo and indicates that RS-0406 has potential as a pharmacotherapeutic intervention for behavioural deficits seen in the early stages of AD, and possibly as an intervention in the development of AD neuropathology. Indeed, an analogue of RS-0406 that could be administered peripherally might be a realistic candidate for the clinical treatment of AD. © 2010 Elsevier B.V.

Scopes D.I.C.,Senexis Ltd | O'Hare E.,Queen's University of Belfast | Jeggo R.,NeuroSolutions Ltd | Whyment A.D.,NeuroSolutions Ltd | And 6 more authors.
British Journal of Pharmacology | Year: 2012

BACKGROUND AND PURPOSE Amyloid-β (Aβ) aggregation into synaptotoxic, prefibrillar oligomers is a major pathogenic event underlying the neuropathology of Alzheimer's disease (AD). The pharmacological and neuroprotective properties of a novel Aβ aggregation inhibitor, SEN1269, were investigated on aggregation and cell viability and in test systems relevant to synaptic function and memory, using both synthetic Aβ1-42 and cell-derived Aβ oligomers. EXPERIMENTAL APPROACH Surface plasmon resonance studies measured binding of SEN1269 to Aβ1-42. Thioflavin-T fluorescence and MTT assays were used to measure its ability to block Aβ1-42-induced aggregation and reduction in cell viability. In vitro and in vivo long-term potentiation (LTP) experiments measured the effect of SEN1269 on deficits induced by synthetic Aβ1-42 and cell-derived Aβ oligomers. Following i.c.v. administration of the latter, a complex (alternating-lever cyclic ratio) schedule of operant responding measured effects on memory in freely moving rats. KEY RESULTS SEN1269 demonstrated direct binding to monomeric Aβ1-42, produced a concentration-related blockade of Aβ1-42 aggregation and protected neuronal cell lines exposed to Aβ1-42. In vitro, SEN1269 alleviated deficits in hippocampal LTP induced by Aβ1-42 and cell-derived Aβ oligomers. In vivo, SEN1269 reduced the deficits in LTP and memory induced by i.c.v. administration of cell-derived Aβ oligomers. CONCLUSIONS AND IMPLICATIONS SEN1269 protected cells exposed to Aβ1-42, displayed central activity with respect to reducing Aβ-induced neurotoxicity and was neuroprotective in electrophysiological and behavioural models of memory relevant to Aβ-induced neurodegeneration. It represents a promising lead for designing inhibitors of Aβ-mediated synaptic toxicity as potential neuroprotective agents for treating AD. © 2012 The Authors. British Journal of Pharmacology.

O'Hare E.,Queen's University of Belfast | Scopes D.I.C.,Senexis Ltd | Kim E.-M.,University of Ulster | Palmer P.,Queen's University of Belfast | And 7 more authors.
International Journal of Neuropsychopharmacology | Year: 2014

Prefibrillar assembly of amyloid-β (Aβ) is a major event underlying the development of neuropathology and dementia in Alzheimer's disease (AD). This study determined the neuroprotective properties of an orally bioavailable Aβ synaptotoxicity inhibitor, SEN1576. Binding of SEN1576 to monomeric Aβ 1-42 was measured using surface plasmon resonance. Thioflavin-T and MTT assays determined the ability of SEN1576 to block Aβ 1-42-induced aggregation and reduction in cell viability, respectively. In vivo long-term potentiation (LTP) determined effects on synaptic toxicity induced by intracerebroventricular (i.c.v.) injection of cell-derived Aβ oligomers. An operant behavioural schedule measured effects of oral administration following i.c.v. injection of Aβ oligomers in normal rats. SEN1576 bound to monomeric Aβ 1-42, protected neuronal cells exposed to Aβ 1-42, reduced deficits in in vivo LTP and behaviour. SEN1576 exhibits the necessary features of a drug candidate for further development as a disease modifying treatment for the early stages of AD-like dementia. © 2013 CINP.

O'Hare E.,Queen's University of Belfast | Scopes D.I.C.,Senexis Ltd | Kim E.-M.,University of Ulster | Palmer P.,Queen's University of Belfast | And 9 more authors.
Neurobiology of Aging | Year: 2013

Oligomers of beta-amyloid (Aβ) are implicated in the early memory impairment seen in Alzheimer's disease before to the onset of discernable neurodegeneration. Here, the capacity of a novel orally bioavailable, central nervous system-penetrating small molecule 5-aryloxypyrimidine, SEN1500, to prevent cell-derived (7PA2 [conditioned medium] CM) Aβ-induced deficits in synaptic plasticity and learned behavior was assessed. Biochemically, SEN1500 bound to Aβ monomer and oligomers, produced a reduction in thioflavin-T fluorescence, and protected a neuronal cell line and primary cortical neurons exposed to synthetic soluble oligomeric Aβ1-42. Electrophysiologically, SEN1500 alleviated the in vitro depression of long-term potentiation induced by both synthetic Aβ1-42 and 7PA2 CM, and alleviated the in vivo depression of long-term potentiation induced by 7PA2 CM, after systemic administration. Behaviorally, oral administration of SEN1500 significantly reduced memory-related deficits in operant responding induced after intracerebroventricular injection of 7PA2 CM. SEN1500 reduced cytotoxicity, acute synaptotoxicity, and behavioral deterioration after in vitro and in vivo exposure to synthetic Aβ and 7PA2 CM, and shows promise for development as a clinically viable disease-modifying Alzheimer's disease treatment. © 2013 Elsevier Inc.

Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: HEALTH-2007-2.2.1-4 | Award Amount: 4.02M | Year: 2008

MEMOSAD aims at defining the molecular mechanisms of Abeta- and Tau-induced synaptotoxicity and at developing disease-modifying therapeutics for the prevention of memory loss in Alzheimer disease (AD). Insoluble aggregates of the two proteins provide the pathological hallmarks of this incurable brain disorder. Early stage AD is characterized by a remarkably pure impairment of declarative memory and several lines of evidence suggest that this memory impairment is independent of the insoluble aggregates, does not require neuronal death and is caused by subtle and transient synaptic changes. The toxic Abeta and Tau species that cause synaptic dysfunction, their mechanism of toxicity and the link between both pathologies remain largely unknown, but recent data suggest that Abeta accumulation triggers Tau pathology. Consequently, primary neuronal cultures and animal models (C.elegans,zebrafish,mouse) will be employed to define the pathologic pathways leading from Abeta through Tau to synaptotoxicity. Initial experiments will investigate the effect of well-defined Abeta species on long term potentiation, synaptic morphology, gene expression, Tau phosphorylation/aggregation, axonal transport and behaviour. Similarly, we will investigate the functional consequences of Tau misfunction, aggregation, hyperphosphorylation and missorting in various cell culture systems (retinal ganglion cells, primary hippocampal neurons, organotypical slices) and animal models, especially with regard to intraneuronal trafficking and synaptic function. Once the toxic Abeta and Tau species are known and their mechanism of toxicity are defined, we will investigate how these pathways interact. Unravelling the pathologic pathways that lead from Abeta through Tau to synaptotoxicity and memory loss should reveal novel points for therapeutic intervention. Our aim is to deliver 3 or 4 validated therapeutic targets and at least 2 compounds with demonstrated therapeutic efficacy in mouse models of AD.

Amijee H.,Senexis Ltd | Amijee H.,University of Manchester | Bate C.,Lane College | Williams A.,Lane College | And 9 more authors.
Biochemistry | Year: 2012

Oligomeric forms of β-amyloid (Aβ) have potent neurotoxic activity and are the primary cause of neuronal injury and cell death in Alzheimer's disease (AD). Compounds that perturb oligomer formation or structure may therefore be therapeutic for AD. We previously reported that d-[(chGly)-(Tyr)-(chGly)-(chGly)-(mLeu)]-NH2 (SEN304) is able to inhibit Aβ aggregation and toxicity, shown primarily by thioflavin T fluorescence and MTT (Kokkoni, N. et al. (2006) N-Methylated peptide inhibitors of β-amyloid aggregation and toxicity. Optimisation of inhibitor structure. Biochemistry45, 9906-9918). Here we extensively characterize how SEN304 affects Aβ(1-42) aggregation and toxicity, using biophysical assays (thioflavin T, circular dichroism, SDS-PAGE, size exclusion chromatography, surface plasmon resonance, traveling wave ion mobility mass spectrometry, electron microscopy, ELISA), toxicity assays in cell culture (MTT and lactate dehydrogenase in human SH-SHY5Y cells, mouse neuronal cell death and synaptophysin) and long-term potentiation in a rat hippocampal brain slice. These data, with dose response curves, show that SEN304 is a powerful inhibitor of Aβ(1-42) toxicity, particularly effective at preventing Aβ inhibition of long-term potentiation. It can bind directly to Aβ(1-42), delay β-sheet formation and promote aggregation of toxic oligomers into a nontoxic form, with a different morphology that cannot bind thioflavin T. SEN304 appears to work by inducing aggregation, and hence removal, of Aβ oligomers. It is therefore a promising lead compound for Alzheimer's disease. © 2012 American Chemical Society.

O'Hare E.,Queen's University of Belfast | Ardis T.,Agri Food and Biosciences Institute of Northern Ireland | Page D.,Queen's University of Belfast | Scopes D.I.C.,Senexis Ltd | Kim E.-M.,University of Ulster
Journal of Alzheimer's Disease | Year: 2013

The current study examined behavioral and histological effects of amyloid-β (Aβ) protein precursor (AβPP) overexpression in transgenic (Tg) rats created using the same gene, mutation, and promoter as the Tg2576 mouse model of Alzheimer's disease (AD). Male Tg+ rats were bred with female wild-type rats to generate litters of hemizygous Tg+ and Tg- offspring. Tg+ rats and Tg- littermates were tested for memory deficits at 4, 8, and 12 months old using a water-maze procedure. There were no significant behavioral differences between Tg+ rats and Tg- littermates at 4 months old but there were significant differences at 8 and 12 months old, and in probe trials at 8 and 12 months old, the Tg+ rats spent significantly less time and covered less distance in the platform zone. Under acquisition of a fixed-consecutive number schedule at 3 months old, Tg- littermates demonstrated a longer latency to learning the response rule than Tg+ rats; while this might seem paradoxical, it is consistent with the role of overexpression of AβPP in learning. Histological analyses revealed activated astrocytes in brains of Tg+ rats but not Tg- littermates at 6 months old, and thioflavin-S positive staining in the hippocampus and cortex of 17-month old Tg+ rats but not Tg - littermates. Quantification of Aβ load in the brain at 22 months indicated high levels of Aβ38, Aβ40, and Aβ42 in the Tg+ rats. These data suggest this model might provide a valuable resource for AD research. © 2013-IOS Press and the authors. All rights reserved.

O'Hare E.,Queen's University of Belfast | Scopes D.I.C.,Senexis Ltd | Treherne J.M.,Senexis Ltd | Monaghan J.,University of Ulster | And 3 more authors.
Journal of Alzheimer's Disease | Year: 2011

Behavioral effects of a novel anti-inflammatory SEN1176 were investigated. This pyrrolo[3,2-e][1,2,4]triazolo[1,5-a]pyrimidine suppresses amyloid-β (Aβ)1-42-induced macrophage production of nitric oxide, TNF-α, IL-1β, and IL-6 in a dose-dependent fashion, an activity profile consistent with SEN1176 being a neuroinflammation inhibitor. Using male Sprague-Dawley rats, SEN1176 was examined relative to detrimental behavioral effects induced following bilateral intrahippocampal (IH) injections of aggregated Aβ1-42. The rats were trained to respond under an alternating-lever cyclic-ratio (ALCR) schedule of food reinforcement, enabling measurement of parameters of operant performance that reflect aspects of learning and memory. Under the ALCR schedule, orally administered SEN1176 at 5, 20, or 30 mg/kg was effective in reducing the behavioral deficit caused by bilateral IH aggregated Aβ1-42 injections in a dose-related manner over a 90-day treatment period. SEN1176 at 20 and 30 mg/kg significantly reduced lever switching errors and, at doses of 5, 10, and 30 mg/kg, significantly reduced incorrect lever perseverations, indicating a reduction of the behavioral deficit induced as a result of inflammation following IH Aβ1-42 injections. When treatment with SEN1176 was instigated 30 days after IH Aβ1-42 injections, it resulted in progressive protection, and withdrawal of SEN1176 treatment 60 days after IH Aβ1-42 injections revealed partial retention of the protective effect. SEN1176 also significantly reduced numbers of activated astrocytes adjacent to the aggregated Aβ1-42 injection sites. These results indicate the potential of SEN1176 for alleviating chronic neuroinflammatory processes related to brain Aβ deposition that affect learning and memory in Alzheimer's disease. © 2011 - IOS Press and the authors. All rights reserved.

The invention relates to novel compounds useful in the treatment and prophylaxis of disease. Compounds of the formula (I) wherein X is halogen, independently selected form chlorine and fluorine and n is 0, 1 or 2, and their pharmaceutically acceptable salts are useful in the treatment and prophylaxis of diseases caused by activation of microglia, particularly Alzheimers disease.

The invention relates to novel compounds useful in the treatment and prophylaxis of disease. Compounds of the formula (I): wherein X is halogen, independently selected form chlorine and fluorine and their pharmaceutically acceptable salts are useful in the treatment and prophylaxis of diseases caused by activation of microglia, particularly Alzheimers disease.

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