Elevation of phospholipase C-β1 expression by amyloid-β facilitates calcium overload in neuronal cells

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia. Amyloid-β (Aβ) has long been considered a key cause of neurodegeneration in the AD brain. Although the mechanisms underlying Aβ-induced neurodegeneration are not fully understood, a number of recent studies have suggested that intracellular calcium overload mediates this process. In this study, we focused on the cellular function of phospholipase C-β1 (PLCB1), which regulates calcium signaling by mediating hydrolysis of phosphatidylinositol 4,5-bisphosphate through G-protein coupled receptor pathways. First, we confirmed that acetylcholine-induced calcium release from intracellular stores of SH-SY5Y cells was significantly increased with Aβ₄₂ oligomer treatment. We further found that PLCB1 expression was upregulated in Aβ₄₂-treated cells, and PLCB1 overexpression in SH-SY5Y cells elicited the calcium overload observed in Aβ-treated cells. In addition, Aβ₄₂ oligomer-induced calcium overload in SH-SY5Y cells was alleviated by knockdown of PLCB1, indicating that PLCB1 plays an essential role in the neurotoxic process initiated by Aβ. The elevation of PLCB1 expression was confirmed in the brain tissues from the 5× familial AD (5×FAD) model mice. These findings suggest that PLCB1 may represent a potential therapeutic target for protecting neuronal cells against excitotoxicity in AD progression.

Keywords: Alzheimer’s disease; Amyloid-β; Calcium overload; Excitotoxicity; Phospholipase C-β1.