Introduction: β-Amyloid protein (Aβ) putatively plays a seminal role in synaptic loss in Alzheimer's disease (AD). While there is no consensus regarding the synaptic-relevant species of Aβ, it is known that Aβ oligomers (AβOs) are noticeably increased in the early stages of AD, localizing at or within the synapse. In cell and animal models, AβOs have been shown to attach to synapses and instigate synapse dysfunction and deterioration. To establish the pathological mechanism of synaptic loss in AD, it will be important to identify the synaptic targets to which AβOs attach.Methods: An unbiased approach using far western ligand blots has identified three synaptic proteins to which AβOs specifically attach. These proteins (p100, p140, and p260) were subsequently enriched by detergent extraction, ultracentrifugation, and CHT-HPLC column separation, and sequenced by LC-MS/MS. P100, p140, and p260 were identified. These levels of AβOs targets in human AD and aging frontal cortexes were analyzed by quantitative proteomics and western-blot. The polyclonal antibody to AβOs was developed and used to block the toxicity of AβOs. The data were analyzed with one-way analysis of variance.Results: AβOs binding proteins p100, p140, and p260 were identified as Na/K-ATPase, synGap, and Shank3, respectively. α3-Na/K-ATPase, synGap, and Shank3 proteins showed loss in the postsynaptic density (PSD) of human AD frontal cortex. In short term experiments, oligomers of Aβ inhibited Na/K-ATPase at the synapse. Na/K-ATPase activity was restored by an antibody specific for soluble forms of Aβ. α3-Na/K-ATPase protein and synaptic β-amyloid peptides were pulled down from human AD synapses by co-immunoprecipitation. Results suggest synaptic dysfunction in early stages of AD may stem from inhibition of Na/K-ATPase activity by Aβ oligomers, while later stages could hypothetically result from disrupted synapse structure involving the PSD proteins synGap and Shank3.Conclusion: We identified three AβO binding proteins as α3-Na/K-ATPase, synGap, and Shank3. Soluble Aβ oligomers appear capable of attacking neurons via specific extracellular as well as intracellular synaptic proteins. Impact on these proteins hypothetically could lead to synaptic dysfunction and loss, and could serve as novel therapeutic targets for AD treatment by antibodies or other agents.

The incidence of AKI in the very elderly hospitalized patients was high. Infections, hypovolemia, nephrotoxic drugs and cardiovascular diseases were among the common causes. Active treatment of primary diseases, avoidance of complications and use of alpha-ketoacid were beneficial for improving the prognosis of the very elderly patients with AKI.

Alteration of behavior and PSD proteins in cerebral cortex and hippocampal synaptosome in the Alzheimer's disease (AD) mouse model were determined. AD was established by intraperitoneal injection of streptozotocin (STZ) in neonatal mice (intraperitoneal AD group) or intracerebroventricular injection of STZ in adult mice (intracerebroventricular AD group). Body weight and blood sugar level were measured. Following Morris water maze (MWM) test and fear-conditioning test, cerebral cortex and hippocampus tissues were collected and the levels of PSD95 and shank3 proteins in these tissues were measured by western blot analysis. The body weight was reduced and the blood sugar concentration was increased in the intraperitoneal AD group compared with the control group. In contrast, the body weight was reduced, while the blood sugar concentration was not increased in the intracerebroventricular AD group compared with the control group. Escape latency in both AD groups was extended compared with the control group. The freezing time in the intraperitoneal AD group was increased, while in the intracerebroventricular AD group, the freezing time was reduced. PSD95 and shank3 proteins in the cerebral cortex in both AD groups were decreased compared with the control group. PSD95 in the hippocampus was reduced in both AD groups compared with the control group. Shank3 in the hippocampus in the intracerebroventricular AD group was significantly reduced compared with the control group. Intraperitoneal injection of STZ in neonatal mice led to elevated blood sugar, impaired spatial memory and enhanced emotional memory when they become adults. In contrast, intracerebroventricular injection of STZ in adults directly led to deteriorated spatial and emotional memory without alteration of blood sugar content, which could be associated with the changes of PSD95 and shank3 proteins in hippocampus.

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