title: LC3 overexpression reduces Aβ neurotoxicity through increasing α7nAchR expression and autophagic activity in neurons and mice.
abstract: Autophagy is an intracellular degradation pathway with dynamic interactions for eliminating damaged organelles and protein aggregates by lysosomal digestion. The EGFP-conjugated microtubule-associated protein 1 light chain 3 (EGFP-LC3) serves to monitor autophagic process. Extracellular β-amyloid peptide accumulation is reported as a major cause in Alzheimer's disease (AD) pathogenesis; large numbers of autophagic vacuoles accumulate in patients' brains. We previously demonstrated that extracellular Aβ (eAβ) induces strong autophagic response and α7nAChR acts as a carrier to bind with eAβ; which further inhibits Aβ-induced neurotoxicity via autophagic degradation. In the present study, we overexpressed LC3 in both neuroblastoma cells (SH-SY5Y/pEGFP-LC3) and mice (TgEGFP-LC3) to assess the effect of LC3 overexpression on Aβ neurotoxicity. SH-SY5Y/pEGFP-LC3 cells and primary cortical neuron cultures derived from E17 (embryonic day 17) TgEGFP-LC3 mice showed not only better resistance against Aβ neurotoxicity but also higher α7nAChR expression and autophagic activity than control. Administration of α-bungarotoxin (α-BTX) to block α7nAChR antagonized the neuroprotective action of SH-SY5Y/pECGF-LC3 cells, suggesting that eAβ binding with α7nAChR is an important step in Aβ detoxification. LC3 overexpression thus exerts neuroprotection through increasing α7nAChR expression for eAβ binding and further enhancing autophagic activity for Aβ clearance in vitro and in vivo.
authors: Department of Medical Research, China Medical University Hospital, Taichung 40447, Taiwan; Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung 40402, Taiwan.
authors: Shih-Ya
authors: SY
authors: Hung
authors: Department of Life Science, National Taiwan University, Taipei 10617, Taiwan.
authors: Wei-Pang
authors: WP
authors: Huang
authors: Pharmacological Institute, College of Medicine, National Taiwan University, Taipei 10051, Taiwan.
authors: Houng-Chi
authors: HC
authors: Liou
authors: Pharmacological Institute, College of Medicine, National Taiwan University, Taipei 10051, Taiwan. Electronic address: wenmei@ntu.edu.tw.
authors: Wen-Mei
authors: WM
authors: Fu
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D002038:Bungarotoxins / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D016229:Amyloid beta-Peptides; D002038:Bungarotoxins; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D018733:Nicotinic Antagonists; D010446:Peptide Fragments; D064569:alpha7 Nicotinic Acetylcholine Receptor; C075222:amyloid beta-protein (1-42); C074636:amyloid beta-protein (25-35); D053148:Caspase 3
keywords: Apoptosis; Autophagy; Aβ; LC3; α7nAChR