Antioxidant and Antiapoptotic Effects of 1,1′-(Biphenyl-4,4′-diyl)-bis(3-(dimethylamino)-propan-1-one) on Protecting PC12 Cells from Aβ-Induced Injury

Novel donepezil-chalcone-rivastigmine hybrids as potential multifunctional anti-Alzheimer's agents: Design, synthesis, in vitro biological evaluation, in vivo and in silico studies

Alzheimer's disease (AD) is a chronic, progressive brain neurodegenerative disorder. Up to now, there is no effective drug to halt or reverse the progress of AD. Given the complex pathogenesis of AD, the multi-target-directed ligands (MTDLs) strategy is considered as the promising therapy. Herein, a series of novel donepezil-chalone-rivastigmine hybrids was rationally designed and synthesized by fusing donepezil, chalone and rivastigmine. The in vitro bioactivity results displayed that compound 10c was a reversible huAChE (IC₅₀ = 0.87 μM) and huBuChE (IC₅₀ = 3.3 μM) inhibitor. It also presented significant anti-inflammation effects by suppressing the level of IL-6 and TNF-α production, and significantly inhibited self-mediated Aβ_1-42 aggregation (60.6%) and huAChE-mediated induced Aβ_1-40 aggregation (46.2%). In addition, 10c showed significant neuroprotective effect on Aβ_1-42-induced PC12 cell injury and activated UPS pathway in HT22 cells to degrade tau and amyloid precursor protein (APP). Furthermore, compound 10c presented good stabilty in artificial gastrointestinal fluids and liver microsomes in vitro. The pharmacokinetic study showed that compound 10c was rapidly absorbed in rats and distributed in rat brain after intragastric administration. The PET-CT imaging demonstrated that [¹¹C]10c could quickly enter the brain and washed out gradually in vivo. Further, compound 10c at a dose of 5 mg/kg improved scopolamine-induced memory impairment, deserving further investigations.

Protective effect of ethyl vanillin against Aβ-induced neurotoxicity in PC12 cells via the reduction of oxidative stress and apoptosis

Increased aggregation of β-amyloid (Aβ) peptides induces oxidative stress, which is considered a major contributor in the development of Alzheimer's disease (AD). Prevention of Aβ-induced neurotoxicity is proposed as a possible modality for treatment of AD. The present study aimed to elucidate possible effects of ethyl vanillin (EVA), an analog of vanillin isolated from vanilla beans, on the Aβ_1-42-induced oxidative injury in PC12 cells. EVA restrained the decrease in PC12 cell viability and apoptosis induction caused by treatment with Aβ_1-42. In addition, EVA markedly alleviated intracellular lipid peroxidation as demonstrated by malondialdehyde levels and reactive oxygen species production in Aβ_1-42-treated PC12 cells. In addition, the reduction in the activity levels of the antioxidative enzymes superoxide dismutase, catalase and glutathione peroxidase was detected in Aβ_1-42-treated PC12 cells. This effect was partially reversed by treatment with EVA. Furthermore, the results indicated that EVA attenuated Aβ_1-42-induced caspase-3 activation and the increase noted in the apoptosis regulator Bcl-2/apoptosis regulator Bax ratio of PC12 cells. These results indicated that EVA could be used as an efficient and novel agent for the prevention of neurodegenerative diseases via inhibition of oxidative stress and cell apoptosis.

Shikonin Protects PC12 Cells Against β-amyloid Peptide-Induced Cell Injury Through Antioxidant and Antiapoptotic Activities

Excessive accumulation of β-amyloid (Aβ) is thought to be a major causative factor in the pathogenesis of Alzheimer's disease (AD). Pretreating Aβ-induced neurotoxicity is a potential therapeutic approach to ameliorate the progression and development of AD. The present study aimed to investigate the neuroprotective effect of shikonin, a naphthoquinone pigment isolated from the roots of the traditional Chinese herb Lithospermum erythrorhizon, on Aβ1-42-treated neurotoxicity in PC12 cells. Pretreating cells with shikonin strongly improved cell viability, decreased the malondialdehyde and reactive oxygen species (ROS) content, and stabilized the mitochondrial membrane potential in Aβ1-42-induced PC12 cells. In addition, shikonin strongly improved the response of the antioxidant system to ROS by increasing the levels of superoxidedismutase, catalase and glutathione peroxidase. Furthermore, shikonin has the ability to reduce proapoptotic signaling by reducing the activity of caspase-3 and moderating the ratio of Bcl-2/Bax. These observations indicate that shikonin holds great potential for neuroprotection via inhibition of oxidative stress and cell apoptosis.

Neuroprotective effects of phenylethanoid glycosides in an in vitro model of Alzheimer's disease

The present study aimed to investigate the neuroprotective effects of phenylethanol glycosides (PhGs) on H₂O₂- and β-amyloid peptide (Aβ)_1-42-induced injury of PC12 cells as an in vitro model of Alzheimer's disease (AD). The optimal induction conditions were established through screening of various incubation times and concentrations. PC12 cells were treated with 0.5 µM Aβ_1-42 and H₂O₂ in the presence of PhGs for 24 h and the cell viability was then evaluated by an MTT assay; lactate dehydrogenase (LDH) release and malondialdehyde (MDA) content were also measured. The optimal conditions for establishing the AD model were the treatment of PC12 cells with 0.5 µM Aβ_1-42 for 48 h, or with 25 µM H₂O₂ dissolved in DMEM with PBS. PhGs at concentrations of 5, 25 and 50 µg/ml increased the viability and decreased LDH and MDA release by PC12 cells injured with Aβ_1-42 or H₂O₂. In conclusion, the model of Aβ_1-42- and H₂O₂-induced PC12 cell injury was successfully established. PhGs were shown to have a significant neuroprotective effect against Aβ_1-42- or H₂O₂-induced cell injury.

UCP2 protects against amyloid beta toxicity and oxidative stress in primary neuronal culture

AD is a common neurodegenerative disease characterized by aggregated amyloid-beta (Aβ) peptide, and oxidative stress, while uncoupling protein 2 (UCP2) is a member of the anion carrier family, predicted the existence of a protein-regulated proton leak with the main purpose of controlling mitochondrial oxidative stress, reduce the generation of superoxide anion. we use the primary hippocampal neurons and add the different doses of Aβ1-40, then observe the change of UCP2 at different concentrations of Aβ, activity of LDH and the content of NO. Our results provide novel insight that UCP2 may protect hippocampal neurons exposed to amyloid β protein through decreasing ROS production. 20μmol/L Aβ1-40 significantly increased the activity of LDH and the content of NO. According to the correlation analysis, NO was significantly correlation with LDH, and UCP2 was significantly correlation with NO. These results suggest the potential of UCP2 as a therapeutic candidate for treating neurodegenerative diseases such as AD.