- Email: [email protected]
PDE9 INHIBITION IMPROVES COGNITION IN MICE BY A MECHANISM DIFFERENT FROM THE ACETYLCHOLINE ESTERASE INHIBITOR DONEPEZIL
Poster Presentations: Tuesday, July 18, 2017
Selaginella delicatula a pteridophyte (popularly known as Sanjeevani) is reported to contain characteristic biflavonoids (amentoflavone) with various biological activities in vitro. In this study, we have tested the hypothesis whether Selaginella flavonoids (SF) possess the potential to abrogate the lipopolysaccharide (LPS)induced biochemical and phenotypic alterations in Drosophila and mice models. Methods: First regimen, mice provided prophylaxis with (SF, 25 & 50mg/kg/d, p.o., for 15d, n¼6) were challenged with LPS (0.5mg/kg/d, ip, last 5 days). Phenotypic manifestations were assessed by employing a battery of behavioral assays for dementia (elevated plus maze, Y-maze, Morris water maze, passive avoidance). Hippocampus region was subjected to biochemical assessments viz., mitochondrial dysfunction, oxidative stress and AChE activity. Second regimen, adult Drosophila (n¼25, 6 replicates) maintained on SF enriched diet (0.05-0.1%, 7 days), were challenged with LPS (200mg, filter discs) and subsequently subjected to behavioral and biochemical tests. Results: LPS exposure induced significant behavioral aberrations among mice as evident from mazes. The passive avoidance score was markedly reduced among the LPS mice indicating severe dementia traits. Interestingly, the extent of LPS-induced behavioral anomalies among mice given SF prophylaxis was significantly attenuated. Additionally SF mice exhibited reduced oxidative stress markers, nitric oxide levels, diminished AChE activity and improved mitochondrial membrane permeability. In the Drosophila we could reproduce the protective effects of SF prophylaxis as evidenced by diminished LPS-induced general aggressive behavior, oxidative markers and AChE activity. Conclusions: These in vivo data are suggestive of potent neuro-attenuatory propensity of Selaginella flavonoids against LPS-induced dementia in mice and Drosophila and merit further mechanistic investigations.
P3-040
PDE9 INHIBITION IMPROVES COGNITION IN MICE BY A MECHANISM DIFFERENT FROM THE ACETYLCHOLINE ESTERASE INHIBITOR DONEPEZIL
Holger Rosenbrock1, Riccardo Giovannini1, Klaus Fuchs2, Cornelia Dorner-Ciossek1, 1Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany; 2Boehringer Ingelheim Pharma GmbH & Co KG, Biberach an der Riss, Germany. Contact e-mail: holger. [email protected] Background: Phosphodiesterases (PDEs) in the brain have shown to
play an important role in synaptic plasticity and cognitive function. Within this target class is PDE9, which specifically regulates the second messenger cGMP in neurons related to NMDA receptor signaling and is expressed in cognition relevant regions of the brain. Thus, PDE9 inhibitors are hypothesized to improve cognitive function via increasing NMDA receptor related cGMP signalling pathway to strengthen synaptic plasticity. This study characterizes the effect of a PDE9 inhibitor (compound A) on reversal of cognitively impaired mice in the T-maze task. In addition, brain cGMP levels were measured in these mice and correlated with memory performance in this task, and furthermore, compared with the effects of the acetylcholine esterase inhibitor donepezil. Methods: The molecular potency of compound A for PDE9 was determined using cytosolic extracts of SF9 insect cells over-expressing fulllength human enzyme employing SPA technology. Regarding cognition, compound A was tested for reversal of MK-801 induced
P945
memory impairment in the mouse T-maze spontaneous alternation task after intraperitoneal administration. Subsequently, cGMP levels in mouse prefrontal cortex, hippocampus and striatum were measured by using enzyme immunoassay technique. Results: The IC50 value of compound A on PDE9 was determined to be 88 nM. Regarding cognition, the PDE9 inhibitor could improve MK-801 induced memory deficits in the mouse T-maze task which was positively correlated with cGMP increase in prefrontal cortex, hippocampus and striatum, brain regions relevant for performance in this task. Donepezil also led to an improvement of memory deficits in the T-maze task, but this was not correlated with cGMP increase in brain. Conclusions: The study shows that compound A is a potent PDE9 inhibitor, and - corroborating previous reports on memory enhancing efficacy of other PDE9 inhibitors in rodents it shows cognition enhancing efficacy in the mouse T-maze task. In contrast to donepezil, improvement of memory performance by PDE9 inhibition was correlated with a cGMP increase in cognitively relevant brain regions. Therefore, these data further demonstrate that PDE9 inhibition may be a potential approach to pharmacologically improve cognition in patients with Alzheimer’s disease by a different mechanism compared to donepezil.
P3-041
LMTM DECREASES a-SYNUCLEIN PATHOLOGY AND REDUCES BEHAVIOURAL DEFECTS IN a-SYNUCLEIN TRANSGENIC MICE
Karima Schwab1, Silke Frahm1, Mandy Magbagbeolu1, Elizabeth A. Goatman2, Charles R. Harrington3, Claude M. Wischik3, Franz Theuring1, 1Charite University Medicine - Institute of Pharmacology, Berlin, Germany; 2School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, United Kingdom; 3TauRx Therapeutics Ltd, Aberdeen, United Kingdom. Contact e-mail: [email protected] Background: a-Synuclein (a-Syn) aggregation is a pathological
feature of synucleinopathies, neurodegenerative disorders that include Parkinson’s disease, with yet no disease modifying therapy available. Methods: We have generated transgenic models in which the expression and aggregation of human a-Syn is induced and have tested whether LMTM, a tau aggregation inhibitor, affects a-Syn aggregation and behavioural defects in mice. Results: Two independent lines of mice (L58 and L62) accumulated neuronal human a-Syn to different extents. There was a significant decrease in a-Syn-positive neurons in multiple brain regions following daily oral treatment with LMTM, evident in both transgenic lines, and a rescue of movement and anxiety-related behavioural defects in L62. Conclusions: LMTM may provide a potential disease modification therapy in synucleinopathies.
P3-042
G-PROTEIN-GATED INWARDLYRECTIFYING POTASSIUM (GIRK/KIR3) CHANNEL ACTIVATION REVERSES SYNAPTIC, NETWORK, AND COGNITIVE HIPPOCAMPAL DEFICITS IN AN ALZHEIMER’S DISEASE MOUSE MODEL
Lydia Jimenez-Diaz1, Irene Sanchez-Rodriguez1, Sara Temprano-Carazo1, Souhail Djebari1, Alberto Najera-Lopez1, Javier Yajeya2, Agnes Gruart3, Jose Maria Delgado-Garcia3, Juan D. Navarro-Lopez1, 1Neurophysiology & Behaviour Lab, University of Castilla-La Mancha, Ciudad Real, Spain;
Selaginella delicatula a pteridophyte (popularly known as Sanjeevani) is reported to contain characteristic biflavonoids (amentoflavone) with various biological activities in vitro. In this study, we have tested the hypothesis whether Selaginella flavonoids (SF) possess the potential to abrogate the lipopolysaccharide (LPS)induced biochemical and phenotypic alterations in Drosophila and mice models. Methods: First regimen, mice provided prophylaxis with (SF, 25 & 50mg/kg/d, p.o., for 15d, n¼6) were challenged with LPS (0.5mg/kg/d, ip, last 5 days). Phenotypic manifestations were assessed by employing a battery of behavioral assays for dementia (elevated plus maze, Y-maze, Morris water maze, passive avoidance). Hippocampus region was subjected to biochemical assessments viz., mitochondrial dysfunction, oxidative stress and AChE activity. Second regimen, adult Drosophila (n¼25, 6 replicates) maintained on SF enriched diet (0.05-0.1%, 7 days), were challenged with LPS (200mg, filter discs) and subsequently subjected to behavioral and biochemical tests. Results: LPS exposure induced significant behavioral aberrations among mice as evident from mazes. The passive avoidance score was markedly reduced among the LPS mice indicating severe dementia traits. Interestingly, the extent of LPS-induced behavioral anomalies among mice given SF prophylaxis was significantly attenuated. Additionally SF mice exhibited reduced oxidative stress markers, nitric oxide levels, diminished AChE activity and improved mitochondrial membrane permeability. In the Drosophila we could reproduce the protective effects of SF prophylaxis as evidenced by diminished LPS-induced general aggressive behavior, oxidative markers and AChE activity. Conclusions: These in vivo data are suggestive of potent neuro-attenuatory propensity of Selaginella flavonoids against LPS-induced dementia in mice and Drosophila and merit further mechanistic investigations.
P3-040
PDE9 INHIBITION IMPROVES COGNITION IN MICE BY A MECHANISM DIFFERENT FROM THE ACETYLCHOLINE ESTERASE INHIBITOR DONEPEZIL
Holger Rosenbrock1, Riccardo Giovannini1, Klaus Fuchs2, Cornelia Dorner-Ciossek1, 1Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany; 2Boehringer Ingelheim Pharma GmbH & Co KG, Biberach an der Riss, Germany. Contact e-mail: holger. [email protected] Background: Phosphodiesterases (PDEs) in the brain have shown to
play an important role in synaptic plasticity and cognitive function. Within this target class is PDE9, which specifically regulates the second messenger cGMP in neurons related to NMDA receptor signaling and is expressed in cognition relevant regions of the brain. Thus, PDE9 inhibitors are hypothesized to improve cognitive function via increasing NMDA receptor related cGMP signalling pathway to strengthen synaptic plasticity. This study characterizes the effect of a PDE9 inhibitor (compound A) on reversal of cognitively impaired mice in the T-maze task. In addition, brain cGMP levels were measured in these mice and correlated with memory performance in this task, and furthermore, compared with the effects of the acetylcholine esterase inhibitor donepezil. Methods: The molecular potency of compound A for PDE9 was determined using cytosolic extracts of SF9 insect cells over-expressing fulllength human enzyme employing SPA technology. Regarding cognition, compound A was tested for reversal of MK-801 induced
P945
memory impairment in the mouse T-maze spontaneous alternation task after intraperitoneal administration. Subsequently, cGMP levels in mouse prefrontal cortex, hippocampus and striatum were measured by using enzyme immunoassay technique. Results: The IC50 value of compound A on PDE9 was determined to be 88 nM. Regarding cognition, the PDE9 inhibitor could improve MK-801 induced memory deficits in the mouse T-maze task which was positively correlated with cGMP increase in prefrontal cortex, hippocampus and striatum, brain regions relevant for performance in this task. Donepezil also led to an improvement of memory deficits in the T-maze task, but this was not correlated with cGMP increase in brain. Conclusions: The study shows that compound A is a potent PDE9 inhibitor, and - corroborating previous reports on memory enhancing efficacy of other PDE9 inhibitors in rodents it shows cognition enhancing efficacy in the mouse T-maze task. In contrast to donepezil, improvement of memory performance by PDE9 inhibition was correlated with a cGMP increase in cognitively relevant brain regions. Therefore, these data further demonstrate that PDE9 inhibition may be a potential approach to pharmacologically improve cognition in patients with Alzheimer’s disease by a different mechanism compared to donepezil.
P3-041
LMTM DECREASES a-SYNUCLEIN PATHOLOGY AND REDUCES BEHAVIOURAL DEFECTS IN a-SYNUCLEIN TRANSGENIC MICE
Karima Schwab1, Silke Frahm1, Mandy Magbagbeolu1, Elizabeth A. Goatman2, Charles R. Harrington3, Claude M. Wischik3, Franz Theuring1, 1Charite University Medicine - Institute of Pharmacology, Berlin, Germany; 2School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, United Kingdom; 3TauRx Therapeutics Ltd, Aberdeen, United Kingdom. Contact e-mail: [email protected] Background: a-Synuclein (a-Syn) aggregation is a pathological
feature of synucleinopathies, neurodegenerative disorders that include Parkinson’s disease, with yet no disease modifying therapy available. Methods: We have generated transgenic models in which the expression and aggregation of human a-Syn is induced and have tested whether LMTM, a tau aggregation inhibitor, affects a-Syn aggregation and behavioural defects in mice. Results: Two independent lines of mice (L58 and L62) accumulated neuronal human a-Syn to different extents. There was a significant decrease in a-Syn-positive neurons in multiple brain regions following daily oral treatment with LMTM, evident in both transgenic lines, and a rescue of movement and anxiety-related behavioural defects in L62. Conclusions: LMTM may provide a potential disease modification therapy in synucleinopathies.
P3-042
G-PROTEIN-GATED INWARDLYRECTIFYING POTASSIUM (GIRK/KIR3) CHANNEL ACTIVATION REVERSES SYNAPTIC, NETWORK, AND COGNITIVE HIPPOCAMPAL DEFICITS IN AN ALZHEIMER’S DISEASE MOUSE MODEL
Lydia Jimenez-Diaz1, Irene Sanchez-Rodriguez1, Sara Temprano-Carazo1, Souhail Djebari1, Alberto Najera-Lopez1, Javier Yajeya2, Agnes Gruart3, Jose Maria Delgado-Garcia3, Juan D. Navarro-Lopez1, 1Neurophysiology & Behaviour Lab, University of Castilla-La Mancha, Ciudad Real, Spain;