scholarly journals Passive immunotherapy for N-truncated tau ameliorates the cognitive deficits in two mouse Alzheimer’s disease models

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Veronica Corsetti ◽  
Antonella Borreca ◽  
Valentina Latina ◽  
Giacomo Giacovazzo ◽  
Annabella Pignataro ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Monoclonal Antibody ◽  
Tau Protein ◽  
Passive Immunization ◽  
Amyloid Plaque ◽  
Long Term Potentiation ◽  
Biologically Active ◽  
Plaque Burden ◽  
Term Potentiation

Abstract Clinical and neuropathological studies have shown that tau pathology better correlates with the severity of dementia than amyloid plaque burden, making tau an attractive target for the cure of Alzheimer’s disease. We have explored whether passive immunization with the 12A12 monoclonal antibody (26–36aa of tau protein) could improve the Alzheimer’s disease phenotype of two well-established mouse models, Tg2576 and 3xTg mice. 12A12 is a cleavage-specific monoclonal antibody which selectively binds the pathologically relevant neurotoxic NH226-230 fragment (i.e. NH2htau) of tau protein without cross-reacting with its full-length physiological form(s). We found out that intravenous administration of 12A12 monoclonal antibody into symptomatic (6 months old) animals: (i) reaches the hippocampus in its biologically active (antigen-binding competent) form and successfully neutralizes its target; (ii) reduces both pathological tau and amyloid precursor protein/amyloidβ metabolisms involved in early disease-associated synaptic deterioration; (iii) improves episodic-like type of learning/memory skills in hippocampal-based novel object recognition and object place recognition behavioural tasks; (iv) restores the specific up-regulation of the activity-regulated cytoskeleton-associated protein involved in consolidation of experience-dependent synaptic plasticity; (v) relieves the loss of dendritic spine connectivity in pyramidal hippocampal CA1 neurons; (vi) rescues the Alzheimer’s disease-related electrophysiological deficits in hippocampal long-term potentiation at the CA3-CA1 synapses; and (vii) mitigates the neuroinflammatory response (reactive gliosis). These findings indicate that the 20–22 kDa NH2-terminal tau fragment is crucial target for Alzheimer’s disease therapy and prospect immunotherapy with 12A12 monoclonal antibody as safe (normal tau-preserving), beneficial approach in contrasting the early Amyloidβ-dependent and independent neuropathological and cognitive alterations in affected subjects.

scholarly journals P2Y1 receptor blockade normalizes network dysfunction and cognition in an Alzheimer’s disease model

2018 ◽  
Vol 215 (6) ◽  
pp. 1649-1663 ◽  
Author(s):  
Nicole Reichenbach ◽  
Andrea Delekate ◽  
Björn Breithausen ◽  
Kevin Keppler ◽  
Stefanie Poll ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Model ◽  
Long Term Potentiation ◽  
Plaque Burden ◽  
Spatial Learning And Memory ◽  
Two Photon Microscopy ◽  
Intracerebroventricular Infusion ◽  
Term Potentiation

Astrocytic hyperactivity is an important contributor to neuronal-glial network dysfunction in Alzheimer’s disease (AD). We have previously shown that astrocyte hyperactivity is mediated by signaling through the P2Y1 purinoreceptor (P2Y1R) pathway. Using the APPPS1 mouse model of AD, we here find that chronic intracerebroventricular infusion of P2Y1R inhibitors normalizes astroglial and neuronal network dysfunction, as measured by in vivo two-photon microscopy, augments structural synaptic integrity, and preserves hippocampal long-term potentiation. These effects occur independently from β-amyloid metabolism or plaque burden but are associated with a higher morphological complexity of periplaque reactive astrocytes, as well as reduced dystrophic neurite burden and greater plaque compaction. Importantly, APPPS1 mice chronically treated with P2Y1R antagonists, as well as APPPS1 mice carrying an astrocyte-specific genetic deletion (Ip3r2−/−) of signaling pathways downstream of P2Y1R activation, are protected from the decline of spatial learning and memory. In summary, our study establishes the restoration of network homoeostasis by P2Y1R inhibition as a novel treatment target in AD.

scholarly journals Genetic Depletion of Amylin/Calcitonin Receptors Improves Memory and Learning in Transgenic Alzheimer’s Disease Mouse Models.

2021 ◽  
Author(s):  
Aarti Patel ◽  
Ryoichi Kimura ◽  
Wen Fu ◽  
Rania Soudy ◽  
David MacTavish ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Amyloid Plaque ◽  
Long Term Potentiation ◽  
Therapeutic Benefit ◽  
Plaque Burden ◽  
Amyloid Precursor Protein Gene ◽  
Amyloid Β Peptide ◽  
Class B

Abstract Based upon its interactions with amyloid β peptide (Aβ), the amylin receptor, a Class B G protein-coupled receptor (GPCR), is a potential modulator of Alzheimer’s disease (AD) pathogenesis. However, past pharmacological approaches have failed to resolve whether activation or blockade of this receptor would have greater therapeutic benefit. To address this issue, we generated compound mice expressing a human amyloid precursor protein gene with familial AD mutations in combination with deficiency of amylin receptors produced by hemizygosity for the critical calcitonin receptor subunit of this heterodimeric GPCR. These compound transgenic AD mice demonstrated attenuated responses to human amylin- and Aβ-induced depression of hippocampal long term potentiation (LTP) in keeping with the genetic depletion of amylin receptors. Both the LTP responses and spatial memory (as measured with Morris Water Maze) in these mice were improved compared to AD mouse controls and, importantly, a reduction in both the amyloid plaque burden and markers of neuroinflammation was observed. Our data support the notion of further development of antagonists of the amylin receptor as AD-modifying therapies.

scholarly journals Genetic Depletion of Amylin/Calcitonin Receptors Improves Memory and Learning in Transgenic Alzheimer’s Disease Mouse Models

2021 ◽  
Author(s):  
Aarti Patel ◽  
Ryoichi Kimura ◽  
Wen Fu ◽  
Rania Soudy ◽  
David MacTavish ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Amyloid Plaque ◽  
Long Term Potentiation ◽  
Therapeutic Benefit ◽  
Plaque Burden ◽  
Amyloid Precursor Protein Gene ◽  
Amyloid Β Peptide ◽  
Class B

AbstractBased upon its interactions with amyloid β peptide (Aβ), the amylin receptor, a class B G protein-coupled receptor (GPCR), is a potential modulator of Alzheimer’s disease (AD) pathogenesis. However, past pharmacological approaches have failed to resolve whether activation or blockade of this receptor would have greater therapeutic benefit. To address this issue, we generated compound mice expressing a human amyloid precursor protein gene with familial AD mutations in combination with deficiency of amylin receptors produced by hemizygosity for the critical calcitonin receptor subunit of this heterodimeric GPCR. These compound transgenic AD mice demonstrated attenuated responses to human amylin- and Aβ-induced depression of hippocampal long-term potentiation (LTP) in keeping with the genetic depletion of amylin receptors. Both the LTP responses and spatial memory (as measured with Morris water maze) in these mice were improved compared to AD mouse controls and, importantly, a reduction in both the amyloid plaque burden and markers of neuroinflammation was observed. Our data support the notion of further development of antagonists of the amylin receptor as AD-modifying therapies.

scholarly journals Torpor enhances synaptic strength and restores memory performance in a mouse model of Alzheimer’s disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christina F. de Veij Mestdagh ◽  
Jaap A. Timmerman ◽  
Frank Koopmans ◽  
Iryna Paliukhovich ◽  
Suzanne S. M. Miedema ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Memory Performance ◽  
Long Term Potentiation ◽  
Fear Memory ◽  
Contextual Fear ◽  
Contextual Fear Memory ◽  
Model Of Alzheimer’S Disease ◽  
Term Potentiation

AbstractHibernation induces neurodegeneration-like changes in the brain, which are completely reversed upon arousal. Hibernation-induced plasticity may therefore be of great relevance for the treatment of neurodegenerative diseases, but remains largely unexplored. Here we show that a single torpor and arousal sequence in mice does not induce dendrite retraction and synapse loss as observed in seasonal hibernators. Instead, it increases hippocampal long-term potentiation and contextual fear memory. This is accompanied by increased levels of key postsynaptic proteins and mitochondrial complex I and IV proteins, indicating mitochondrial reactivation and enhanced synaptic plasticity upon arousal. Interestingly, a single torpor and arousal sequence was also sufficient to restore contextual fear memory in an APP/PS1 mouse model of Alzheimer’s disease. Our study demonstrates that torpor in mice evokes an exceptional state of hippocampal plasticity and that naturally occurring plasticity mechanisms during torpor provide an opportunity to identify unique druggable targets for the treatment of cognitive impairment.

Neuroprotective properties of mitochondria-targeted antioxidants of the SkQ-type

2016 ◽  
Vol 27 (8) ◽  
pp. 849-855 ◽  
Author(s):  
Nickolay K. Isaev ◽  
Elena V. Stelmashook ◽  
Elisaveta E. Genrikhs ◽  
Galina A. Korshunova ◽  
Natalya V. Sumbatyan ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Area ◽  
Hippocampal Slices ◽  
Amyloid Β ◽  
Long Term Potentiation ◽  
Term Potentiation ◽  
Neuroprotective Action

AbstractIn 2008, using a model of compression brain ischemia, we presented the first evidence that mitochondria-targeted antioxidants of the SkQ family, i.e. SkQR1 [10-(6′-plastoquinonyl)decylrhodamine], have a neuroprotective action. It was shown that intraperitoneal injections of SkQR1 (0.5–1 μmol/kg) 1 day before ischemia significantly decreased the damaged brain area. Later, we studied in more detail the anti-ischemic action of this antioxidant in a model of experimental focal ischemia provoked by unilateral intravascular occlusion of the middle cerebral artery. The neuroprotective action of SkQ family compounds (SkQR1, SkQ1, SkQTR1, SkQT1) was manifested through the decrease in trauma-induced neurological deficit in animals and prevention of amyloid-β-induced impairment of long-term potentiation in rat hippocampal slices. At present, most neurophysiologists suppose that long-term potentiation underlies cellular mechanisms of memory and learning. They consider inhibition of this process by amyloid-β1-42as anin vitromodel of memory disturbance in Alzheimer’s disease. Further development of the above studies revealed that mitochondria-targeted antioxidants could retard accumulation of hyperphosphorylated τ-protein, as well as amyloid-β1-42, and its precursor APP in the brain, which are involved in developing neurodegenerative processes in Alzheimer’s disease.

scholarly journals Therapeutic potential of astaxanthin and superoxide dismutase in Alzheimer's disease

Open Biology ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 210013
Author(s):  
Vyshnavy Balendra ◽  
Sandeep Kumar Singh
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Superoxide Dismutase ◽  
Antioxidant System ◽  
Tau Protein ◽  
Therapeutic Potential ◽  
Plaque Burden ◽  
Memory Decline ◽  
Endogenous Antioxidants ◽  
The Brain

Oxidative stress, the imbalance of the antioxidant system, results in an accumulation of neurotoxic proteins in Alzheimer's disease (AD). The antioxidant system is composed of exogenous and endogenous antioxidants to maintain homeostasis. Superoxide dismutase (SOD) is an endogenous enzymatic antioxidant that converts superoxide ions to hydrogen peroxide in cells. SOD supplementation in mice prevented cognitive decline in stress-induced cells by reducing lipid peroxidation and maintaining neurogenesis in the hippocampus. Furthermore, SOD decreased expression of BACE1 while reducing plaque burden in the brain. Additionally, Astaxanthin (AST), a potent exogenous carotenoid, scavenges superoxide anion radicals. Mice treated with AST showed slower memory decline and decreased depositions of amyloid-beta (A β ) and tau protein. Currently, the neuroprotective potential of these supplements has only been examined separately in studies. However, a single antioxidant cannot sufficiently resist oxidative damage to the brain, therefore, a combinatory approach is proposed as a relevant therapy for ameliorating pathological changes in AD.

scholarly journals Progressive Age-Related Impairment of the Late Long-Term Potentiation in Alzheimer's Disease Presenilin-1 Mutant Knock-in Mice

2010 ◽  
Vol 19 (3) ◽  
pp. 1021-1033 ◽  
Author(s):  
Alexandra Auffret ◽  
Vanessa Gautheron ◽  
Mark P. Mattson ◽  
Jean Mariani ◽  
Catherine Rovira
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Long Term Potentiation ◽  
Presenilin 1 ◽  
Age Related ◽  
Term Potentiation

scholarly journals Microglial-associated responses to comorbid amyloid pathology and hyperhomocysteinemia in an aged knock-in mouse model of Alzheimer’s disease

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
David J. Braun ◽  
Edgardo Dimayuga ◽  
Josh M. Morganti ◽  
Linda J. Van Eldik
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Inflammatory Responses ◽  
Specific Effect ◽  
Amyloid Plaque ◽  
Plaque Burden ◽  
Amyloid Pathology ◽  
Model Of Alzheimer’S Disease ◽  
B Vitamin

Abstract Background Elevated blood homocysteine levels, termed hyperhomocysteinemia (HHcy), is a prevalent risk factor for Alzheimer’s disease (AD) in elderly populations. While dietary supplementation of B-vitamins is a generally effective method to lower homocysteine levels, there is little if any benefit to cognition. In the context of amyloid pathology, dietary-induced HHcy is known to enhance amyloid deposition and certain inflammatory responses. Little is known, however, about whether there is a more specific effect on microglia resulting from combined amyloid and HHcy pathologies. Methods The present study used a knock-in mouse model of amyloidosis, aged to 12 months, given 8 weeks of B-vitamin deficiency-induced HHcy to better understand how microglia are affected in this comorbidity context. Results We found that HHcy-inducing diet increased amyloid plaque burden, altered the neuroinflammatory milieu, and upregulated the expression of multiple damage-associated and “homeostatic” microglial genes. Conclusions Taken together, these data indicate complex effects of comorbid pathologies on microglial function that are not driven solely by increased amyloid burden. Given the highly dynamic nature of microglia, their central role in AD pathology, and the frequent occurrence of various comorbidities in AD patients, it is increasingly important to understand how microglia respond to mixed pathological processes.

scholarly journals TDP-43 interacts with amyloid-β, inhibits fibrillization, and worsens pathology in a model of Alzheimer’s disease

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yao-Hsiang Shih ◽  
Ling-Hsien Tu ◽  
Ting-Yu Chang ◽  
Kiruthika Ganesan ◽  
Wei-Wei Chang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Long Term Potentiation ◽  
Model Of Alzheimer’S Disease ◽  
Term Potentiation ◽  
Spatial Memory Deficit ◽  
Aβ Aggregation ◽  
Intrahippocampal Injection

AbstractTDP-43 inclusions are found in many Alzheimer’s disease (AD) patients presenting faster disease progression and greater brain atrophy. Previously, we showed full-length TDP-43 forms spherical oligomers and perturbs amyloid-β (Aβ) fibrillization. To elucidate the role of TDP-43 in AD, here, we examined the effect of TDP-43 in Aβ aggregation and the attributed toxicity in mouse models. We found TDP-43 inhibited Aβ fibrillization at initial and oligomeric stages. Aβ fibrillization was delayed specifically in the presence of N-terminal domain containing TDP-43 variants, while C-terminal TDP-43 was not essential for Aβ interaction. TDP-43 significantly enhanced Aβ’s ability to impair long-term potentiation and, upon intrahippocampal injection, caused spatial memory deficit. Following injection to AD transgenic mice, TDP-43 induced inflammation, interacted with Aβ, and exacerbated AD-like pathology. TDP-43 oligomers mostly colocalized with intracellular Aβ in the brain of AD patients. We conclude that TDP-43 inhibits Aβ fibrillization through its interaction with Aβ and exacerbates AD pathology.

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