- Email: [email protected]
SITE-SPECIFIC PHOSPHORYLATION OF TAU INHIBITS AMYLOID-β TOXICITY IN ALZHEIMER’S MICE
P1294 P4-093
Poster Presentations: Wednesday, July 19, 2017 SITE-SPECIFIC PHOSPHORYLATION OF TAU INHIBITS AMYLOID-b TOXICITY IN ALZHEIMER’S MICE
Arne Ittner, Dementia Research Unit, School of Medical Sciences, University of New South Wales, Sydney, Australia. Contact e-mail: [email protected] Background: Amyloid-b (Ab) toxicity in Alzheimer’s disease
(AD) is considered to be mediated by phosphorylated tau protein. Methods: Our study used mouse genetics, adeno-associated virus-mediated gene delivery, primary neuronal culture, biochemical, imaging and histological techniques as well as telemetric electroencephalography and behavioural tests including standard memory testing and touch screen operant chambers. Results: In contrast to previous assumptions on tau phosphorylation, we found that, at least in early disease, site-specific phosphorylation of tau inhibited Ab toxicity. This specific tau phosphorylation was mediated by the neuronal p38 mitogen-activated protein kinase p38g and interfered with postsynaptic excitotoxic signaling complexes engaged by Ab. Accordingly, depletion of p38g exacerbated neuronal circuit aberrations, cognitive deficits, and premature lethality in a mouse model of AD, whereas increasing the activity of p38g abolished these deficits. Furthermore, mimicking site-specific tau phosphorylation alleviated Abinduced neuronal death and offered protection from excitotoxicity. Conclusions: Our work provides insights into postsynaptic processes in AD pathogenesis and challenges a purely pathogenic role of tau phosphorylation in neuronal toxicity.
P4-094
TARGETING TAU AGGREGATION IN BRAIN SLICE CULTURE MODELS OF TAUOPATHIES
Cara L. Croft, Pedro E. Cruz, Marshall S. Goodwin, Carolina Ceballos-Diaz, Kevin Strang, Paramita Chakrabarty, Yona Levites, Benoit I. Giasson, Todd E. Golde, University of Florida, Gainesville, FL, USA. Contact e-mail: [email protected] Background: There is an absence of in vitro models which develop the complex pathological features of human tauopathies and Alzheimer’s disease (AD). Organotypic brain slice cultures (BSCs) in combination with AAV-mediated gene delivery provide an intact ex vivo system in which to potentially study these disease features and develop relevant therapeutics. Methods: rAAV vectors and methods have been developed that enable specific transduction of neurons, astrocytes, oligodendrocytes and microglia in BSCs. BSCs containing the cortex and hippocampus were prepared from postnatal day 8/9 B6/ C3H mice and transduced on DIV 0 with AAV8 to deliver wild-type or mutated human MAPT or other AD-relevant genes. These transduced BSCs were then maintained in culture for several weeks and characterized histologically and biochemically to identify any disease-relevant changes. In order to validate the system as a platform to identify therapeutics, tau aggregation in BSCs was targeted using several different strategies. Results: AAV-tau transduced BSCs develop sarkosyl-insoluble, hyperphosphorylated tau species and ‘tangle-like’ pathology upon immunohistochemical examination after 4 weeks in culture. AAV delivered genes can persist in these cultures for at least 10 months. These newly character-
ized models of tauopathy were then used to identify potential therapeutic candidates and pathways to target tau aggregation. Conclusions: AAV-transduced BSCs provide an excellent ex vivo platform for the study of tauopathies and Alzheimer’s disease. This model system can be used to identify tau anti-aggregation agents and enable us to dissect mechanisms underlying these disorders.
P4-095
NILOTINIB REDUCES PHOSPHORYLATED NEUROFILAMENTS AND CORRELATES WITH COGNITIVE IMPROVEMENT IN PARKINSON’S DISEASE WITH DEMENTIA AND LEWY BODY DEMENTIA
Charbel E-H Moussa1, Fernando Pagan2, Michaeline Hebron1, 1 Georgetown University, Washington, D.C., USA; 2Georgetown University, Washington, D.C., USA. Contact e-mail: [email protected] Background: Parkinson’s disease (PD) is a neurodegenerative
disorder that affects motor and non-motor functions. Our pre-clinical data indicate that the tyrosine kinase inhibitor (TKI) Nilotinib improves motor behavior and cognition in several models of neurodegeneration. Nilotinib is FDAapproved for the treatment of chronic myeloid leukemia (CML) at 800mg oral dose twice daily. Methods: This is a retrospective biomarker study of an open-label clinical study to examine the safety and efficacy of lower doses (<50% of CML dose) of Nilotinib in human. We randomized 12 participants with mid-late stage PD with dementia (PDD) or Lewy body dementia (LBD) into 150mg (N¼5) or 300mg (N¼7) groups, who received oral daily doses of Nilotinib for 6 months. Results: We found that most patients who received 150mg Nilotinib were diagnosed with LBD and treatment resulted in cognitive improvement as measured by Mini-Mental Status Exam (MMSE). ELISA measurement of CSF cell death marker (phosphorylated) p-neurofilament was significantly reduced. The change in CSF biomarkers correlated (Pearson’s R) with improvement in MMSE (3 points) in LBD patients. Patients who received 300mg Nilotinib were diagnosed with PD or PDD and also showed significant reduction in CSF pneurofilaments between baseline and 6 months treatment. MMSE was improved (4 points) in these patients. There was a correlation (Pearson’s R) between reduction in CSF p-neurofilaments and MMSE (3 points) in PD and PDD. Conclusions: Nilotinib significantly reduces cell death marker p-neurofilaments in CSF in both 150mg (LBD) and 300mg (PDD) groups and this reduction in p-neurofilaments correlates with cognitive improvement, suggesting that p-neurofilaments may be a good biomarker that correlates with clinical cognitive outcomes. These data indicate that further clinical studies are needed to determine the effects of Nilotinib in dementia, including AD and LBD.
P4-096
OVEREXPRESSION OF 3R-TAU LEADS TO SYNAPTIC DEFECTS AND MEMORY IMPAIRMENT BY OXIDATIVE STRESSMEDIATED DNA DOUBLE STRAND BREAKS
Cheng Xu, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong
Poster Presentations: Wednesday, July 19, 2017 SITE-SPECIFIC PHOSPHORYLATION OF TAU INHIBITS AMYLOID-b TOXICITY IN ALZHEIMER’S MICE
Arne Ittner, Dementia Research Unit, School of Medical Sciences, University of New South Wales, Sydney, Australia. Contact e-mail: [email protected] Background: Amyloid-b (Ab) toxicity in Alzheimer’s disease
(AD) is considered to be mediated by phosphorylated tau protein. Methods: Our study used mouse genetics, adeno-associated virus-mediated gene delivery, primary neuronal culture, biochemical, imaging and histological techniques as well as telemetric electroencephalography and behavioural tests including standard memory testing and touch screen operant chambers. Results: In contrast to previous assumptions on tau phosphorylation, we found that, at least in early disease, site-specific phosphorylation of tau inhibited Ab toxicity. This specific tau phosphorylation was mediated by the neuronal p38 mitogen-activated protein kinase p38g and interfered with postsynaptic excitotoxic signaling complexes engaged by Ab. Accordingly, depletion of p38g exacerbated neuronal circuit aberrations, cognitive deficits, and premature lethality in a mouse model of AD, whereas increasing the activity of p38g abolished these deficits. Furthermore, mimicking site-specific tau phosphorylation alleviated Abinduced neuronal death and offered protection from excitotoxicity. Conclusions: Our work provides insights into postsynaptic processes in AD pathogenesis and challenges a purely pathogenic role of tau phosphorylation in neuronal toxicity.
P4-094
TARGETING TAU AGGREGATION IN BRAIN SLICE CULTURE MODELS OF TAUOPATHIES
Cara L. Croft, Pedro E. Cruz, Marshall S. Goodwin, Carolina Ceballos-Diaz, Kevin Strang, Paramita Chakrabarty, Yona Levites, Benoit I. Giasson, Todd E. Golde, University of Florida, Gainesville, FL, USA. Contact e-mail: [email protected] Background: There is an absence of in vitro models which develop the complex pathological features of human tauopathies and Alzheimer’s disease (AD). Organotypic brain slice cultures (BSCs) in combination with AAV-mediated gene delivery provide an intact ex vivo system in which to potentially study these disease features and develop relevant therapeutics. Methods: rAAV vectors and methods have been developed that enable specific transduction of neurons, astrocytes, oligodendrocytes and microglia in BSCs. BSCs containing the cortex and hippocampus were prepared from postnatal day 8/9 B6/ C3H mice and transduced on DIV 0 with AAV8 to deliver wild-type or mutated human MAPT or other AD-relevant genes. These transduced BSCs were then maintained in culture for several weeks and characterized histologically and biochemically to identify any disease-relevant changes. In order to validate the system as a platform to identify therapeutics, tau aggregation in BSCs was targeted using several different strategies. Results: AAV-tau transduced BSCs develop sarkosyl-insoluble, hyperphosphorylated tau species and ‘tangle-like’ pathology upon immunohistochemical examination after 4 weeks in culture. AAV delivered genes can persist in these cultures for at least 10 months. These newly character-
ized models of tauopathy were then used to identify potential therapeutic candidates and pathways to target tau aggregation. Conclusions: AAV-transduced BSCs provide an excellent ex vivo platform for the study of tauopathies and Alzheimer’s disease. This model system can be used to identify tau anti-aggregation agents and enable us to dissect mechanisms underlying these disorders.
P4-095
NILOTINIB REDUCES PHOSPHORYLATED NEUROFILAMENTS AND CORRELATES WITH COGNITIVE IMPROVEMENT IN PARKINSON’S DISEASE WITH DEMENTIA AND LEWY BODY DEMENTIA
Charbel E-H Moussa1, Fernando Pagan2, Michaeline Hebron1, 1 Georgetown University, Washington, D.C., USA; 2Georgetown University, Washington, D.C., USA. Contact e-mail: [email protected] Background: Parkinson’s disease (PD) is a neurodegenerative
disorder that affects motor and non-motor functions. Our pre-clinical data indicate that the tyrosine kinase inhibitor (TKI) Nilotinib improves motor behavior and cognition in several models of neurodegeneration. Nilotinib is FDAapproved for the treatment of chronic myeloid leukemia (CML) at 800mg oral dose twice daily. Methods: This is a retrospective biomarker study of an open-label clinical study to examine the safety and efficacy of lower doses (<50% of CML dose) of Nilotinib in human. We randomized 12 participants with mid-late stage PD with dementia (PDD) or Lewy body dementia (LBD) into 150mg (N¼5) or 300mg (N¼7) groups, who received oral daily doses of Nilotinib for 6 months. Results: We found that most patients who received 150mg Nilotinib were diagnosed with LBD and treatment resulted in cognitive improvement as measured by Mini-Mental Status Exam (MMSE). ELISA measurement of CSF cell death marker (phosphorylated) p-neurofilament was significantly reduced. The change in CSF biomarkers correlated (Pearson’s R) with improvement in MMSE (3 points) in LBD patients. Patients who received 300mg Nilotinib were diagnosed with PD or PDD and also showed significant reduction in CSF pneurofilaments between baseline and 6 months treatment. MMSE was improved (4 points) in these patients. There was a correlation (Pearson’s R) between reduction in CSF p-neurofilaments and MMSE (3 points) in PD and PDD. Conclusions: Nilotinib significantly reduces cell death marker p-neurofilaments in CSF in both 150mg (LBD) and 300mg (PDD) groups and this reduction in p-neurofilaments correlates with cognitive improvement, suggesting that p-neurofilaments may be a good biomarker that correlates with clinical cognitive outcomes. These data indicate that further clinical studies are needed to determine the effects of Nilotinib in dementia, including AD and LBD.
P4-096
OVEREXPRESSION OF 3R-TAU LEADS TO SYNAPTIC DEFECTS AND MEMORY IMPAIRMENT BY OXIDATIVE STRESSMEDIATED DNA DOUBLE STRAND BREAKS
Cheng Xu, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong