Nicotine Promotes AβPP Nonamyloidogenic Processing via RACK1-Dependent Activation of PKC in SH-SY5Y-AβPP695 Cells

Article type: Research Article

Authors: He, Wenting^{a; b; c; d; e} | Tu, Man^{a; b; c; d; e} | Du, Yehong^{a; b; c; d; e} | Li, Junjie^{a; b; c; d; e} | Pang, Yayan^{a; b; c; d; e} | Dong, Zhifang^{a; b; c; d; e; *}

Affiliations: [a] Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China | [b] Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China | [c] National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China | [d] China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China | [e] Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China

Correspondence: [*] Correspondence to: Zhifang Dong, Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children’s Hospital of Chongqing Medical University, Chongqing 400014, China. E-mail: zfdong@cqmu.edu.cn.

Abstract: Background:Accumulation of amyloid-β (Aβ) peptides, generated from amyloid-β precursor protein (AβPP) amyloidogenic processing, is one of the most salient disease hallmarks of Alzheimer’s disease (AD). Nicotine is able to promote α-secretase-mediated AβPP nonamyloidogenic processing and increase the release of sAβPPα and C-terminal fragment of 83 amino acids (C83). However, the potential molecular mechanism remains elusive. Objective:The aim of the present study was to investigate the effect of nicotine on AβPP processing in SH-SY5Y cells that stably express human Swedish mutant AβPP695 (SH-SY5Y-AβPP695). Methods:The expression of AβPP and its C-terminal fragments including C99, C89, and C83, was measured in SH-SY5Y-AβPP695 cells treated with nicotine for 6 h. Protein kinase C (PKC) antagonist Ro30-8220 or agonist PMA was used to determine the role of PKC in AβPP processing. Lentivirus-mediated shRNA targeting receptor for activated C-kinase 1 (RACK1) gene was added into the media to knockdown RACK1 expression, and then AβPP processing was examined. Results:The results showed that 6 h of nicotine exposure increased the expression of α-secretase (ADAM10) and C83 in a dose dependent manner. While the β-secretase (BACE1), AβPP amyloidogenic processing products C89 and C99 as well as Aβ peptides (including Aβ40 and Aβ42) remained unchanged. We also found that nicotine elevated the expression of phosphorylated PKC (P-PKC) and RACK1 on the cytomembrane. PKC antagonist Ro30-8220 treatment prevented the increase of ADAM10 and C83 by nicotine. Genetic knockdown RACK1 significantly inhibited P-PKC, and consequently abolished the increase of ADAM10 and C83 by nicotine. Conclusion:Taken together, these results indicate that nicotine effectively promotes AβPP nonamyloidogenic processing via RACK1-dependent activation of PKC in SH-SY5Y-AβPP695 cells and could be a potential molecule for AD treatment.

Keywords: Alzheimer’s disease, nicotine, protein kinase C, receptor for activated C-kinase 1

DOI: 10.3233/JAD-200003

Journal: Journal of Alzheimer's Disease, vol. 75, no. 2, pp. 451-460, 2020