Date of Award

2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Pharmacology and Toxicology

First Advisor

Kenza Benzeroual

Committee Chair and Members

Kenza Benzeroual, Chair

Eun-Jung Park

Ahmed Abu Fayyad

Keywords

Alzheimer's diseases, Apoptosis, Lipopolysaccharide, Neurodegenerative diseases, SHSY5Y cells, Western blot

Abstract

Background:

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the extracellular accumulation of Amyloid-β (Aβ) plaques, causing neurotoxicity and leading to neurodegeneration. Amyloid precursor protein (APP) is processed into various Aβ isoforms. It has been shown to contribute to mitochondrial dysfunction and oxidative stress, activating mitochondrial apoptotic pathways and pro-inflammatory factors and leading to neuronal cell death. Memantine (MN) and Bacopa Monnieri (BM) are postulated to have neuroprotective effects, most likely via anti-amyloidogenic and anti-apoptotic mechanisms. The in vitro models suggest a potential for further development of biologically based adjuvant therapeutics for neurodegenerative diseases. However, more precise identification of the bioactive metabolites in these extracts and their mechanisms of action in vitro is required to achieve this goal.

Objective:

The present study investigated the neuroprotective effects of Memantine (MN), an FDA-approved drug, and the Ayurvedic nootropic drug Bacopa Monnieri (BM) on the amyloid precursor protein (APP) expression and the apoptotic and inflammatory pathways in the lipopolysaccharide (LPS)-induced SHSY5Y cells toxicity. Specifically, we investigated the effect of MN and BM on the expression of APP for the anti-amyloidogenic pathway, NF-kB for the anti-inflammatory pathway, and BCL-2, cytochrome C (Cyt C), and caspase-3 for the apoptotic pathway.

Methods:

SHSY5Y cells were pretreated with varying concentrations of Memantine (0.01 μM, 0.5 μM, and 1 μM) and Bacopa Monnieri (1μg/ml,10 μg/ml, and 20 μg/ml) for 2 hours prior to lipopolysaccharide (50 μg/ml) exposure for 24 hours. Cell viability, amyloidosis, inflammation, and apoptosis in LPS-induced SHSY5Y cell death were assessed. Cell viability was analyzed by MTT assay. Anti-amyloidogenic, antiinflammation, and anti-apoptotic effects were analyzed using western blot.

Results:

The results showed that the pretreatment with MN of LPS-induced toxicity in SHSY5Y cells significantly increased cell viability and decreased APP expression, thus limiting further neurotoxicity. In parallel, the apoptotic pathway triggered by LPS was reduced, as represented by a dose-dependent increase in the expression of BCL-2, an anti-apoptotic marker, and a decrease in the expression of cytochrome C and caspase-3, as well as a decrease in the expression of the inflammatory marker NF-kB. On the other hand, pretreatment with BM also protected the cells from LPS-induced neurotoxicity by significantly increasing cell viability and decreasing APP expression. In addition, BM also prevented apoptosis by decreasing the expression of cytochrome C and caspase 3. It also prevented neuroinflammation by reducing the expression of NF-kB. Both MN and BM show anti-amyloidogenic, anti-inflammatory, and anti-apoptotic effects in LPS-exposed neuronal cells.

Conclusion:

The present study suggests that BM can be considered a potential adjuvant therapy for preventing or delaying the progression of neurodegeneration in AD.

Available for download on Saturday, August 16, 2025

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