- Email: [email protected]
Characterization of tool compounds targeting tau oligomers
P906
Developing Topics
of disease-modifying therapeutics. However, a major impediment to progress may lie in fundamental differences between humans and animal model species, largely rodents. Disruption of hippocampal insulin signaling has recently been described in the brains of AD patients and animal models of disease, which could contribute to cognitive impairment in this disease. Therefore, drugs that can restore normal insulin function in the central nervous system have been recently suggested as a promising novel approach to treat AD. Methods: Here, we evaluated the neuroprotective effects of liraglutide in cynomolgus macaques (Macaca fascicularis) that received intracerebroventricular injections of Ab oligomers (AbOs). Liraglutide is an anti-diabetic agent that activates pathways common to insulin signaling through stimulation of glucagon-like peptide 1 (GLP-1) receptors. Nine female cynomolgus macaques were used. Three of them were sham-operated and served as controls. We performed intracerebroventricular (i.c.v.) injections of AbOs into six cynomolgus macaques. Two of these monkeys had been pre-treated with daily i.p. injections of liraglutide. Liraglutide administration continued daily until the last injection of oligomers. Brain sections were used for immunohistochemystry to evaluate the levels of synaptic markers. Results: We found that AbOs induced a decrease in synapse number in the primate brain and reduced the levels of NMDA (GluN1 and GluN2B subunits), AMPA (GluA1 and GluA2 subunits) and insulin receptors. Liraglutide attenuated the impact of AbOs on synapses and on plasticity related receptors. Conclusions: These results establish the protective actions of liraglutide in the primate brain and indicates that a primate model of AD may be valuable not only for studying mechanisms responsible for AbOs toxicity, but also for exploring and evaluating new preventive therapeutic strategies for AD.
P4-318
T3D-959: A MULTI-FACETED DISEASE REMEDIAL DRUG CANDIDATE FOR THE TREATMENT OF ALZHEIMER’S DISEASE
John Didsbury1, Suzanne de la Monte2, 1T3D Therapeutics, Inc., Raleigh, NC, USA; 2Lifespan, Rhode Island Hospitals, Providence, RI, USA. Contact e-mail: [email protected] Background: T3D-959, a dual nuclear receptor agonist and former diabetes drug candidate has been repositioned as an Alzheimer’s disease (AD)-modifying therapy. The ability of the Phase 1completed drug to act in a multi-faceted manner to improve multiple AD pathologies was tested in vivo and ex vivo in a rat model of AD. The unique combination of mechanisms of action, PPAR delta as primary target and PPAR gamma as a secondary target, convey distinctive efficacy and safety profiles. Methods: Intracerebral (i.c.) streptozotocin (STZ)-exposed rats were used as an in vivo model of sporadic AD. Ex vivo studies of these animals used hippocampal/temporal lobe brain slice cultures for evaluating the effects of T3D-959. Twenty four hours after i.c. STZ treatment rat pups are sacrificed and brain slice cultures established for 24h prior to drug administration for 48h (0.5-1.0uM). In vivo studies involved dosing animals therapeutically after i.c. STZ exposure at 0.3 to 3.0mg/kg/ d via oral gavage for 28d. Results: Ex vivo results demonstrated significant improvements in neuronal cell survival, oxidative stress and brain morphology with nearly complete restoration of cortical architecture. Significant decreases in phospo-tau and restoration of beta amyloid peptide to normal levels was also observed. These ex vivo improvements in AD pathologies translated in vivo, with
T3D-959 significantly improving both cognitive and motor function impairments, i.e. spatial learning and memory in the Morris water maze test and motor function in rotarod testing. Conclusions: Pre-clinical proof of concept has been demonstrated that T3D-959 can improve multiple pathologies of AD resulting in significant improvements in cognitive and motor function, two key impairments in AD. These results support two theses; (1) that effective disease modification in AD will require multiple pathologies be improved in concert, nuclear receptors as a target class provide that potential, and (2) treating AD as a metabolic disease has the potential to be disease remedial. A Phase 2a trial of T3D-959 in mild-to-moderate AD patients has been initiated.
P4-319
CHARACTERIZATION OF TOOL COMPOUNDS TARGETING TAU OLIGOMERS
Pavan K. Krishnamurthy1, Daisy Romero1, Patricia Lopez1, Giulia Papiani1, Eliot J. Davidowitz1, James G. Moe2, 1Oligomerix, Inc., New York, NY, USA; 2Oligomerix, Inc., Valhalla, NY, USA. Contact e-mail: [email protected] Background: AD is a disorder with unknown aetiology. Tau oligomers may play a key role in the progression of AD pathology. They have been shown to be toxic to neurons, inhibit long term potentiation in hippocampal slices, impair the formation of associative fear memory in mice, induce synaptic dysfunction, and induce the propagation of tau pathology during disease progression. Hence targeting tau oligomers for drug discovery for the development of both symptom-modifying and disease-modifying therapeutics would be highly desirable. Methods: Our drug discovery platform has used a systematic approach to progress from screening for compounds, validating hits, testing tool compounds in situ, and conducting validation studies in an in vivo model. A highly diverse library of 100,000 drug-like small molecules was screened using a proximity based assay for detection of tau self-association. Hits were validated and dose response and neurocytotoxicity assays were performed. Medicinal chemistry analysis was used to select hits for secondary assays. Stably transfected cell lines were established for tau oligomer formation assays and acute toxicity of selected tool compounds was assessed in wild type mice. Proof-of-concept studies in the JNPL3 mouse model (Taconic) were initiated to demonstrate target engagement in vivo and to validate the screening approach. Results: 57 druglike molecules predicted to have good CNS penetration were selected from 11 chemical series and 19 singletons, and the most active hits were chosen as tool compounds. A tool compound was chosen for methods development for in vivo studies. An initial Pilot Validation Study with 34 JNPL3 mice showed that the tool compound was non-toxic and effective at reducing insoluble and phospho tau levels in a dose dependent manner. A larger scale study with 20 JNPL3 mice per cohort showed that the tool compound reduced phospho-tau levels at Ser202 and Thr231 sites, and reduced pathological 64kDa tau. Analysis of behavioral and histological results are under way. Conclusions: Methods have been developed to study small molecule tau aggregation inhibitors in vivo. Larger cohort sizes may be necessary to achieve statistical significance due to the variability of the JNPL3 phenotype.
JULYGLOBAL: Ensure there is a space after the colon following Background, Methods, Results, Conclusions. 22, 2015
Developing Topics
of disease-modifying therapeutics. However, a major impediment to progress may lie in fundamental differences between humans and animal model species, largely rodents. Disruption of hippocampal insulin signaling has recently been described in the brains of AD patients and animal models of disease, which could contribute to cognitive impairment in this disease. Therefore, drugs that can restore normal insulin function in the central nervous system have been recently suggested as a promising novel approach to treat AD. Methods: Here, we evaluated the neuroprotective effects of liraglutide in cynomolgus macaques (Macaca fascicularis) that received intracerebroventricular injections of Ab oligomers (AbOs). Liraglutide is an anti-diabetic agent that activates pathways common to insulin signaling through stimulation of glucagon-like peptide 1 (GLP-1) receptors. Nine female cynomolgus macaques were used. Three of them were sham-operated and served as controls. We performed intracerebroventricular (i.c.v.) injections of AbOs into six cynomolgus macaques. Two of these monkeys had been pre-treated with daily i.p. injections of liraglutide. Liraglutide administration continued daily until the last injection of oligomers. Brain sections were used for immunohistochemystry to evaluate the levels of synaptic markers. Results: We found that AbOs induced a decrease in synapse number in the primate brain and reduced the levels of NMDA (GluN1 and GluN2B subunits), AMPA (GluA1 and GluA2 subunits) and insulin receptors. Liraglutide attenuated the impact of AbOs on synapses and on plasticity related receptors. Conclusions: These results establish the protective actions of liraglutide in the primate brain and indicates that a primate model of AD may be valuable not only for studying mechanisms responsible for AbOs toxicity, but also for exploring and evaluating new preventive therapeutic strategies for AD.
P4-318
T3D-959: A MULTI-FACETED DISEASE REMEDIAL DRUG CANDIDATE FOR THE TREATMENT OF ALZHEIMER’S DISEASE
John Didsbury1, Suzanne de la Monte2, 1T3D Therapeutics, Inc., Raleigh, NC, USA; 2Lifespan, Rhode Island Hospitals, Providence, RI, USA. Contact e-mail: [email protected] Background: T3D-959, a dual nuclear receptor agonist and former diabetes drug candidate has been repositioned as an Alzheimer’s disease (AD)-modifying therapy. The ability of the Phase 1completed drug to act in a multi-faceted manner to improve multiple AD pathologies was tested in vivo and ex vivo in a rat model of AD. The unique combination of mechanisms of action, PPAR delta as primary target and PPAR gamma as a secondary target, convey distinctive efficacy and safety profiles. Methods: Intracerebral (i.c.) streptozotocin (STZ)-exposed rats were used as an in vivo model of sporadic AD. Ex vivo studies of these animals used hippocampal/temporal lobe brain slice cultures for evaluating the effects of T3D-959. Twenty four hours after i.c. STZ treatment rat pups are sacrificed and brain slice cultures established for 24h prior to drug administration for 48h (0.5-1.0uM). In vivo studies involved dosing animals therapeutically after i.c. STZ exposure at 0.3 to 3.0mg/kg/ d via oral gavage for 28d. Results: Ex vivo results demonstrated significant improvements in neuronal cell survival, oxidative stress and brain morphology with nearly complete restoration of cortical architecture. Significant decreases in phospo-tau and restoration of beta amyloid peptide to normal levels was also observed. These ex vivo improvements in AD pathologies translated in vivo, with
T3D-959 significantly improving both cognitive and motor function impairments, i.e. spatial learning and memory in the Morris water maze test and motor function in rotarod testing. Conclusions: Pre-clinical proof of concept has been demonstrated that T3D-959 can improve multiple pathologies of AD resulting in significant improvements in cognitive and motor function, two key impairments in AD. These results support two theses; (1) that effective disease modification in AD will require multiple pathologies be improved in concert, nuclear receptors as a target class provide that potential, and (2) treating AD as a metabolic disease has the potential to be disease remedial. A Phase 2a trial of T3D-959 in mild-to-moderate AD patients has been initiated.
P4-319
CHARACTERIZATION OF TOOL COMPOUNDS TARGETING TAU OLIGOMERS
Pavan K. Krishnamurthy1, Daisy Romero1, Patricia Lopez1, Giulia Papiani1, Eliot J. Davidowitz1, James G. Moe2, 1Oligomerix, Inc., New York, NY, USA; 2Oligomerix, Inc., Valhalla, NY, USA. Contact e-mail: [email protected] Background: AD is a disorder with unknown aetiology. Tau oligomers may play a key role in the progression of AD pathology. They have been shown to be toxic to neurons, inhibit long term potentiation in hippocampal slices, impair the formation of associative fear memory in mice, induce synaptic dysfunction, and induce the propagation of tau pathology during disease progression. Hence targeting tau oligomers for drug discovery for the development of both symptom-modifying and disease-modifying therapeutics would be highly desirable. Methods: Our drug discovery platform has used a systematic approach to progress from screening for compounds, validating hits, testing tool compounds in situ, and conducting validation studies in an in vivo model. A highly diverse library of 100,000 drug-like small molecules was screened using a proximity based assay for detection of tau self-association. Hits were validated and dose response and neurocytotoxicity assays were performed. Medicinal chemistry analysis was used to select hits for secondary assays. Stably transfected cell lines were established for tau oligomer formation assays and acute toxicity of selected tool compounds was assessed in wild type mice. Proof-of-concept studies in the JNPL3 mouse model (Taconic) were initiated to demonstrate target engagement in vivo and to validate the screening approach. Results: 57 druglike molecules predicted to have good CNS penetration were selected from 11 chemical series and 19 singletons, and the most active hits were chosen as tool compounds. A tool compound was chosen for methods development for in vivo studies. An initial Pilot Validation Study with 34 JNPL3 mice showed that the tool compound was non-toxic and effective at reducing insoluble and phospho tau levels in a dose dependent manner. A larger scale study with 20 JNPL3 mice per cohort showed that the tool compound reduced phospho-tau levels at Ser202 and Thr231 sites, and reduced pathological 64kDa tau. Analysis of behavioral and histological results are under way. Conclusions: Methods have been developed to study small molecule tau aggregation inhibitors in vivo. Larger cohort sizes may be necessary to achieve statistical significance due to the variability of the JNPL3 phenotype.
JULY