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Inactive myocyte enhancer factor 2D (MEF2D) and alpha-synuclein (α-syn) aggregation will cause neuronal death. MEF2D or α-syn degradation is also associated with macroautophagy, chaperone-mediated autophagy (CMA) and heat-shock protein 70 (HSP70). We found that β-asarone had positive effects on treating 6-hydroxydopamine (6-OHDA)-induced rats, but mechanisms of β-asarone affecting on MEF2D and α-syn via regulating the HSP70/MAPK/MEF2D/Beclin-1 pathway remain unclear. Unilateral 6-OHDA injection into the medial forebrain bundle was used to create PD rats, which were divided into four groups and administered for 30days: 6-OHDA model group, MEF2D inhibitor-treated group (SB203580, 0.5mg/kg, i.p.), MEF2D activator-treated group (LiCl, 100mg/kg, i.p.), β-asarone-treated group (15mg/kg, p.o.). Expressions of tyrosine hydroxylase (TH), α-syn, heat-shock cognate protein 70 (HSC70), lysosome-associated membrane protein type 2a (LAMP-2A), MEF2D, HSP70, Beclin-1, light chain 3B (LC3B) and p62 in the mesencephalon were measured after 30-day administration. α-syn, Beclin-1 and LC3B levels were higher in the 6-OHDA model group, while TH, MEF2D, HSC70, LAMP-2A, p62 levels were lower compared to the sham-operated group. Our results also showed thatβ-asarone treatment reduced protein and mRNA levels of α-syn, Beclin-1 and LC3B, but increased HSP70, TH, MEF2D, HSC70, LAMP-2A and p62 levels compared to the 6-OHDA model group. Additionally, certain correlations among α-syn, TH, Beclin-1, LC3B, p62, HSP70, LAMP-2A and MEF2D were also discovered in this study. These findings suggested that β-asarone treatment could increase MEF2D and TH as well as reduce α-syn to protect against 6-OHDA induced damage in PD rat mesencephalon via modulating the HSP70/MAPK/MEF2D/Beclin-1 pathway., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Alzheimer's disease (AD) is an age related and progressive neurodegenerative disease. Autophagy is a self-degradative process and plays a critical role in removing long-lived proteins and damaged organelles. Recent evidence suggests that autophagy might be involved in the pathogenesis of AD. β-asarone have various neuroprotective effects. However, the effect of β-asarone on autophagy in amyloid β-peptide (Aβ) induced cell injury is unclear, and little is known about the signaling pathway of β-asarone in autophagy regulation. The aim of the present study was to determine whether β-asarone protects cells from Aβ1-42 induced cytotoxicity via regulation of Beclin-1 dependent autophagy and its regulating signaling pathway. We examined effects of β-asarone on cell morphology, cell viability, neuron specific enolase (NSE) levels, autophagosomes and regulating Beclin-1, p-Akt and p-mTOR expressions in Aβ1-42 treated PC12 cells. We found that β-asarone could maintain the original morphology of cells and increase cell viability and decrease NSE levels significantly. Meanwhile, β-asarone decreased Beclin-1 expression significantly. In addition, β-asarone can increase levels of p-Akt and p-mTOR. These results showed that β-asarone protected cells from Aβ1-42 induced cytotoxicity and attenuated autophagy via activation of Akt-mTOR signaling pathway, which could be involved in neuroprotection of β-asarone against Aβ toxicity. Our findings suggest that β-asarone might be a potential preventive drug for AD., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Alzheimer's disease (AD) is an age-related and progressive neurodegenerative disease. Beta-amyloid (Aβ) plays an important role in the pathogenesis of AD. Autophagy is a self-degradative process and its related protein Beclin-1 is involved in the initiation of autophagy. However, the role of Beclin-1 in the pathogenesis of AD is rarely reported. In this study, we examined cell viability and medium levels of neuron-specific enolase (NSE) in PC12 cells incubated with gradient concentrations of Aβ(1-42) (0.625, 1.25, 2.5, 5, 10 μM) for 6, 12, 24, 48, and 72 h, drew the index changes curves, and investigated the correlation between them. The result showed that cell viability was negatively correlated with NSE levels. Based on this study, Beclin-1 expression was quantitatively detected in Aβ1-42-treated PC12 cells and the dynamic changes curve of Beclin-1 was drawn from 3 to 72 h. Beclin-1 expression was positively correlated with cell viability. Furthermore, both autophagy inhibitor 3-methyladenine (3-MA) and autophagy activator rapamycin were used to investigate the effect of autophagy on Aβ(1-42)-induced cell injury. Aβ(1-42)-induced Beclin-1 expression was further upregulated by rapamycin but was downregulated by 3-MA. Moreover, cell viability was increased by rapamycin but was decreased by 3-MA, and NSE was decreased by rapamycin but was increased by 3-MA, suggesting that activation of Beclin-1-dependent autophagy before the damage occurred can prevent neuronal cell death, while inhibition of Beclin-1-dependent autophagy can hastened cell death. These findings indicate that increasing Beclin-1-dependent autophagy may have a preventive effect before the AD occurred.

Autophagy is usually up-regulated to provide more ATP in response to starvation or OGD (oxygen-glucose deprivation), but the relationship between autophagy and ATP, [Ca2+]i (intracellular free Ca2+ concentration) or MMP (mitochondrial membrane potential) during reoxygenation is not yet fully clear. The role of autophagy is unknown in PC12 cells subjected to 2 h OGD with different time points of reoxygenation. In the present study, we showed that Beclin-1 was up-regulated beginning at 0 h reoxygenation peaking at 24 h and lasting for 48 h. Cell viability was decreased from 0 to 48 h reoxygenation, reaching its minimum at 10 h reoxygenation. ATP was decreased from 0 to 10 h reoxygenation, reaching its minimum at 4 h reoxygenation. A significant negative correlation was observed between ATP and Beclin-1 ( r = −0.61, P<0.05) at 0 h reoxygenation, but ATP was not significant related ( r = 0.24, P>0.05) to Beclin-1 at 24 h reoxygenation. Besides, Nimodipine, a calcium antagonist, significantly reduced [Ca2+]i and Beclin-1, but increased MMP in OGD/R-treated cells. At 24 h reoxygenation, Beclin-1 expression reached its maximum, cell viability continued to increase, and ATP was higher than that before OGD. These results suggest that energy metabolism dysfunction can induce autophagy during OGD in PC12 cells. Increased [Ca2+]i and decreased MMP may induce autophagy during reoxygenation in PC12 cells. Autophagy may be a protective effect on PC12 cells treated with different time points of reoxygenation after 2 h OGD. [ABSTRACT FROM AUTHOR]