Alzheimer’s disease (AD) is characterized by the accumulation of β-amyloid peptide (Aβ) and loss of neurons. Recently, a growing body of evidences have indicated that as a herbal compound naturally derived from grapes, resveratrol modulates the pathophysiology of AD, however, with a largely unclear mechanism. Therefore, we aimed to investigate the protection of resveratrol against the neurotoxicity of β-amyloid peptide 25–35 (Aβ25–35) and further explore its underlying mechanism in the present study. PC12 cells were injuried by Aβ25–35, and resveratrol at different concentrations was added into the culture medium. We observed that resveratrol increased cell viability through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) colorimetric assays. Flow cytometry indicated the reduction of cell apoptosis by resveratrol. Moreover, resveratrol also stabilized the intercellular Ca2+ homeostasis and attenuated Aβ25–35 neurotoxicity. Additionally, Aβ25–35-suppressed silent information regulator 1 (SIRT1) activity was significantly reversed by resveratrol, resulting in the downregulation of Rho-associated kinase 1 (ROCK1). Our results clearly revealed that resveratrol significantly protected PC12 cells and inhibited the β-amyloid-induced cell apoptosis through the upregulation of SIRT1. Moreover, as a downstream signal molecule, ROCK1 was negatively regulated by SIRT1. Taken together, our study demonstrated that SIRT1-ROCK1 pathway played a critical role in the pathomechanism of AD.

Resveratrol (3,5,4'-tihydroxy-trans-stilbene), a polyphenolic phytoalexin found in the skin and seeds of grapes, has been reported to possess a wide range of biological and pharmacological activities including antioxidant, anti-inflammatory, and antimutagenic effects. The present study intended to explore the neuroprotective effects of resveratrol against Aβ25-35 -induced neurotoxicity of cultured mouse cortical neurons and the possible mechanisms involved. For this purpose, mouse cortical neurons were cultured and exposed to 30 μM Aβ25-35 in the absence or presence of resveratrol (5, 10, and 25 μM). In addition, the potential contribution of the SIRT1/Akt1 neuroprotective pathway in resveratrol-mediated protection against Aβ25-35 -induced neurotoxicity was also investigated. The results showed that resveratrol dose-dependently increased cell viability and reduced the number of apoptotic cells as measured by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) activity assay, reactive oxygen species (ROS) activity assay, and Hoechst/PI double staining. Further study revealed that resveratrol through activation of SIRT1/Akt1 to avert apoptosis. These findings raise the possibility that resveratrol may be a potent therapeutic compound against the neurodegenerative diseases.

Quantitative description of ascorbate secretion at a single-cell level is of great importance in physiological studies; however, most studies on the ascorbate secretion have so far been performed through analyzing cell extracts with high performance liquid chromatography, which lacks time resolution and analytical performance on a single-cell level. This study demonstrates a single-cell amperometry with carbon fiber microelectrodes (CFEs) to selectively monitor amperometric vesicular secretion of endogenous ascorbate from a single rat adrenal chromaffin cell. The CFEs are electrochemically pretreated in a weakly basic solution (pH 9.5), and such pretreatment essentially enables the oxidation of ascorbate to occur at a relatively low potential (i.e., 0.0 V vs Ag/AgCl), and further a high selectivity for ascorbate measurement over endogenously existing electroactive species such as epinephrine, norepinephrine, and dopamine. The selectivity is ensured by much larger amperometric response at the pretreated CFEs toward ascorbate over those toward other endogenously existing electroactive species added into the solution or ejected to the electrode with a micropuffer pipet, and by the totally suppressed current response by adding ascorbate oxidase into the cell lysate. With the pretreated CFE-based single-cell amperometry developed here, exocytosis of endogenous ascorbate of rat adrenal chromaffin cells is directly observed and ensured with the calcium ion-dependent high K-induced secretion of endogenous ascorbate from the cells. Moreover, the quantitative information on the exocytosis of endogenous ascorbate is provided.

DJ‐1 protein deficiency caused by PARK7 gene mutation has been suggested to closely relate to Parkinson's disease (PD), mainly through the attenuation D2 dopamine receptor activity in mice; however, whether or how it affects the vesicular storage and exocytosis of neurochemicals remains unclear. By using electrochemical methods at a single vesicle/cell level with nano/micro‐tip electrodes, we for the first time find that DJ‐1 protein deficiency caused by PARK7 gene knockout (KO) in mice has little effect on vesicular catecholamine content but significantly prolongs the exocytotic events, especially the closing time of exocytotic fusion pores. Further studies suggest the inhibition of α‐synuclein aggregation by DJ‐1 protein might be one way that DJ‐1 protein acts on neurotransmission. This finding offers the first direct link between DJ‐1 protein deficiency and vesicular chemical storage and release of chemicals, providing a new chemical insight into the pathology of PD caused by PARK7 gene mutation.

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