davunetide and Memory-Disorders

Memory loss and cognition decline are the main clinical manifestations of Alzheimer's disease (AD). Amyloid β protein (Aβ) aggregated in the brain is one of the key pathological characteristics of AD and responsible for the deficits in learning and memory. It is reported that davunetide, an octapeptide derived from activity-dependent neuroprotective protein (ADNP), inhibited Aβ aggregation and Aβ-induced neurotoxicity. To further characterize the neuroprotective roles of davunetide and its possible mechanism, the present study investigated the effects of davunetide on Aβ1-42-induced impairments in spatial memory, synaptic plasticity and hippocampal AKT level. In Morris water maze (MWM) test, bilateral intrahippocampal injection of Aβ1-42 significantly increased escape latency and decreased target quadrant swimming time of rats, while three weeks of intranasal application of davunetide reversed the Aβ1-42-induced learning deficits and memory loss in a dose-dependent manner. In vivo field potentiation recording showed that Aβ1-42 suppressed long-term potentiation (LTP) of excitatory postsynaptic potential (fEPSP) in the hippocampal CA1 region of rats, while davunetide effectively blocked the suppression of LTP, without affecting paired-pulse facilitation (PPF). Western blotting experiments showed a significant decrease in the level of hippocampal p-AKT (Ser473), not total AKT, in Aβ1-42 only group, which was mostly antagonized by davunetide treatment. These findings demonstrate that davunetide, probably by enhancing PI3K/AKT pathway, plays an important positive role in attenuating Aβ1-42-induced impairments in spatial memory and synaptic plasticity, suggesting that davunetide could be an effective therapeutic candidate for the prevention and treatment of neurodegenerative disease such as AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Disease Models, Animal; Electric Stimulation; Hippocampus; Long-Term Potentiation; Male; Maze Learning; Memory Disorders; Oligopeptides; Oncogene Protein v-akt; Peptide Fragments; Rats; Rats, Sprague-Dawley; Reaction Time; Signal Transduction; Spatial Learning

A phage-displayed peptide TGN was used as a targeting motif to help the delivery of NAP-loaded nanoparticles across the blood-brain barrier (BBB), which sets an obstacle for brain delivery of NAP in vivo.. Intracerebroventricular injection of Aβ₁₋₄₀ into mice was used to construct in vivo model of Alzheimer's disease. The water maze task was performed to evaluate the effects of the NAP formulations on learning and memory deficits in mice. The neuroprotective effect was tested by detecting acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activity and conducting histological assays.. Intravenous administration of NAP-loaded TGN modified nanoparticles (TGN-NP/NAP) has shown better improvement in spatial learning than NAP solution and NAP-loaded nanoparticles in Morris water maze experiment. The crossing number of the mice with memory deficits recovered after treatment with TGN-NP/NAP in a dose dependent manner. Similar results were also observed in AChE and ChAT activity. No morphological damage and no detectable Aβ plaques were found in mice hippocampus and cortex treated with TGN-NP/NAP.. TGN modified nanoparticles could be a promising drug delivery system for peptide and protein drug such as NAP to enter the brain and play the therapeutic role.

Topics: Acetylcholinesterase; Alzheimer Disease; Animals; Blood-Brain Barrier; Brain; Choline O-Acetyltransferase; Drug Delivery Systems; Male; Memory Disorders; Mice; Nanoparticles; Neuroprotective Agents; Oligopeptides; Polyethylene Glycols; Polyglactin 910

Hypoxia-ischemia (HI) is a common cause of neonatal brain damage with lifelong morbidities in which current therapies are limited. In this study, we investigated the effect of neuropeptide NAP (NAPVSIPQ) on early cerebral oxidative stress, long-term neurological function and brain injury after neonatal HI. Seven-day-old rat pups were subjected to an HI model by applying a unilateral carotid artery occlusion and systemic hypoxia. The animals were randomly assigned to groups receiving an intraperitoneal injection of NAP (3 μg/g) or vehicle immediately (0 h) and 24 h after HI. Brain DNA damage, lipid peroxidation and reduced glutathione (GSH) content were determined 24 h after the last NAP injection. Cognitive impairment was assessed on postnatal day 60 using the spatial version of the Morris water maze learning task. Next, the animals were euthanized to assess the cerebral hemispheric volume using the Cavalieri principle associated with the counting point method. We observed that NAP prevented the acute HI-induced DNA and lipid membrane damage and also recovered the GSH levels in the injured hemisphere of the HI rat pups. Further, NAP was able to prevent impairments in learning and long-term spatial memory and to significantly reduce brain damage up to 7 weeks following the neonatal HI injury. Our findings demonstrate that NAP confers potent neuroprotection from acute brain oxidative stress, long-term cognitive impairment and brain lesions induced by neonatal HI through, at least in part, the modulation of the glutathione-mediated antioxidant system.

Topics: Animals; Animals, Newborn; Cerebral Cortex; Cognition Disorders; Comet Assay; DNA Damage; Female; Functional Laterality; Glutathione; Hippocampus; Hypoxia-Ischemia, Brain; Lipid Peroxidation; Maze Learning; Memory Disorders; Neuroprotective Agents; Oligopeptides; Oxidation-Reduction; Oxidative Stress; Pregnancy; Rats; Rats, Wistar

NAP (NAPVSIPQ) provides broad neuroprotection through microtubule interaction. Here, NAP was investigated for neuroprotection in an in vivo tauopathy model. Transgenic mice (2-month-old) that express the human double mutant tau protein [P301S;K257T] fused to the tau promoter, were subjected to daily intranasal drug treatment for approximately 5 months. Results showed increased performance in the NAP-treated mice compared to controls, as demonstrated in the Morris water maze, (p<0.05). Treatment continued for 5 additional months and mouse cortices were biochemically analyzed. Protein extraction identified increased tau protein content in the heat-stable soluble fraction, which contains microtubule-associated tau, in the 1-year-old NAP-treated mice as compared to vehicle-controls. Tau phosphorylation (Ser 202) increased in the tau-transgenic mice compared to control mice, and was significantly reduced in NAP-treated mice. The current studies show for the first time activity for NAP in a "pure" tauopathy model, positioning it as a promising drug candidate in multiple neurodegenerative tauopathies.

Topics: Animals; Brain; Cytoprotection; Disease Models, Animal; Humans; In Vitro Techniques; Memory Disorders; Mice; Mice, Transgenic; Neurofibrillary Tangles; Neuroprotective Agents; Oligopeptides; Phosphorylation; Solubility; tau Proteins; Tauopathies; Treatment Outcome

The prophylactic neuroprotective effects of NAP, a femtomolar-acting neuroprotective peptide were tested in a mouse model of head trauma. NAP was injected for the first 3 weeks of life and head injury was initiated at 4 months. After trauma, mice were tested for their performance by evaluating damaged motor ability, balance and alertness. Comparison of the performance 1 h and 1 week after injury indicated that NAP treatment resulted in faster and enhanced recovery. In a 5-day Morris water maze test with mice suffering moderate to severe injuries, only the NAP-treated group learned to find the hidden platform in the maze. Furthermore, NAP treatment resulted in decreased mRNA expression of the inflammation marker, Mac-1. Thus, a potentially new prophylactic treatment against neurodegeneration is suggested.

Topics: Aging; Animals; Animals, Newborn; Craniocerebral Trauma; Injections, Subcutaneous; Learning Disabilities; Male; Maze Learning; Memory Disorders; Mice; Neuroprotective Agents; Oligopeptides; Recovery of Function; Trauma Severity Indices; Wounds, Nonpenetrating