Effects of Amyloid Precursor Protein Overexpression on NF-κB, Rho-GTPase and Pro-Apoptosis Bcl-2 Pathways in Neuronal Cells.

Rhun Yian Koh,Shee Man Voon,Chooi Ling Lim,Hong Hao Chan,Meng Liy Pan,Chee Onn Leong,Yong Qi Leong

doi:10.52547/rbmb.9.4.417

Abstract

Alzheimer's disease (AD) is a neurodegenerative disorder that causes cognitive dysfunction. Previous studies have suggested that amyloid plaques, mainly comprising of amyloid-beta peptides, play a pivotal role in AD pathophysiology. This study focuses on the evaluation of the effects of amyloid precursor protein (APP) overexpression on NF-κB, Rho-GTPase and Bcl-2 mediated pro-apoptotic pathways in neuronal cells. A lentiviral transduction system was used to generate SH-SY5Y cells overexpressing APP. Immunoblotting was conducted to determine expression levels of NF-κB, Rho-GTPase, and Bcl-2 family proteins in the APP overexpressed cells. In the NF-κB signaling pathway, APP-overexpressing SH-SY5Y cells showed that there was a reduction of p-NF-κB (p< 0.05) and IKKα. Subsequently, there was upregulation of protein expression of NF-Κb, IKKβ and IκBα. On the other hand, protein expression of RhoC (p< 0.05) and Rac1/2/3 was upregulated as compared to the control group. Meanwhile, a decrease in RhoA, Cdc42 (p< 0.05) and p-Rac1/cdc42 protein levels was observed in the APP-overexpressed group. Lastly, in the pro-apoptotic pathway, the expression of Bcl-2, Bid, Bok and Puma (p< 0.05) was up regulated in the APP-overexpressed group. Downregulation of Bad and Bim expression was observed in the APP-overexpressed as compared to the control group, and Bax expression remained unchanged in the APP-overexpressed group. APP overexpression regulated signaling in the NF-κB, Rho-GTPase and Bcl-2 family pathways in neuronal cells, suggesting that these are involved in promoting neuronal survival and modulating synaptic plasticity in AD. However, further studies are essential to elucidate the APP-mediated mechanism of action.

Highlights

Alzheimer’s disease (AD) is a neurodegenerative disease affecting the hippocampal and entorhinal cortical regions of the brain, with the progression of cognitive deterioration correlating with age [1]
In order to generate the AD-like in vitro model, SH-SY5Y cells were transduced with lentiviralconstructs containing amyloid precursor protein (APP)
Fig 2. demonstrates that the protein expression of p-NF-κB and IKKα were down-regulated in the APP-overexpressed group

Summary

Introduction

Alzheimer’s disease (AD) is a neurodegenerative disease affecting the hippocampal and entorhinal cortical regions of the brain, with the progression of cognitive deterioration correlating with age [1]. In the non-amyloidogenic pathway, α-secretase cleaves APP to release soluble APP protein alpha (sAPPα) and C83, which are further processed by γ-secretase to produce soluble fragments p3 and AICD [7]. This study focuses on the evaluation of the effects of amyloid precursor protein (APP) overexpression on NF-κB, Rho-GTPase and Bcl-2 mediated pro-apoptotic pathways in neuronal cells. Immunoblotting was conducted to determine expression levels of NF-κB, Rho-GTPase, and Bcl-2 family proteins in the APP overexpressed cells. Conclusions: APP overexpression regulated signaling in the NF-κB, Rho-GTPase and Bcl-2 family pathways in neuronal cells, suggesting that these are involved in promoting neuronal survival and modulating synaptic plasticity in AD. Further studies are essential to elucidate the APP-mediated mechanism of action

Methods

Results

Conclusion