Differential localization of acetylcholinesterase in neuronal and non‐neuronal cells

Abstract

Acetylcholinesterase (AChE) expression is regulated in cell types at the transcriptional and translational levels. In this study, we characterized and compared AChE catalytic activity, mRNA, protein expression, and protein localization in a variety of neuronal (SH-SY5Y neuroblastoma and primary cerebellar granule neurons (CGN)) and non-neuronal (LLC-MK2, HeLa, THP-1, and primary astrocytes) cell types. All cell lines expressed AChE catalytic activity; however the levels of AChE-specific activity were higher in neuronal cells than in the non-neuronal cell types. CGN expressed significantly more AChE activity than SH-SY5Y cells. All cell lines analyzed expressed AChE protein at equivalent levels, as well as mRNA splice variants. Localization of AChE was characterized by immunofluorescence and confocal microscopy. SH-SY5Y, CGN, and nerve-growth factor-differentiated PC-12 cells exhibited a pattern of AChE localization characterized as diffuse in the cytoplasm and punctate staining along neurites and on the plasma membrane. The localization in HeLa, LLC-MK2, fibroblasts, and undifferentiated PC-12 cells was significantly different than in neuronal cells-AChE was intensely localized in the perinuclear region, without staining near or on the plasma membrane. Based on the evidence presented here, we hypothesize that the presence of AChE protein doesn't correlate with catalytic activity, and the diffuse cytoplasmic and plasma membrane localization of AChE is a property of neuronal cell types. Keywords acetylcholinesterase; confocal microscopy; cerebellar granule neuron; neuroblastoma; SH-SY5Y; HeLa; PC-12 Acetylcholinesterase (AChE) belongs to the serine hydrolase family that contains the α/β hydrolase fold as a common structural element [Ollis et al., 1992]. The catalytic active site of AChE is made up of a precise arrangement of active site functional groups that catalyze the hydrolytic breakdown of esters that bear quaternary ammonium groups. The biological importance of AChE-catalyzed hydrolysis is manifested in the rapid termination of the neuronal impulse that occurs when acetylcholine (ACh) is released into the synaptic cleft. AChE rapidly hydrolyzes ACh into acetic acid and choline at extremely fast turnover rates [Taylor and Radic, 1994].

Temporospatial localization of acetylcholinesterase activity in the dental epithelium during mouse tooth development

“…The inhibitors BW284C51 and iso-OMPA have been useful in separating AChE and BuChE activities from the ChE activity, respectively (Bicker et al, 2004;Thullbery et al, 2005). In the present study, the AChE and BuChE activities revealed by each inhibitor perfectly matched the components of ChE activity determined in the absence of any inhibitor.…”

Intracellular distribution of 3,6-bis(3-alkylguanidino)acridines determines their cytotoxicity

“…Considering localization of the GNDA at the plasma membrane, proteins of the plasma membrane could interact with these substances. Based on the literature reports [23] we supposed that acetylcholinesterase (EC 3.1.1.7; AChE) among others could be a cellular target of GNDAs in the SH-SY5Y cells, therefore effects of GNDAs on the enzyme activity in SH-SY5Y cells were investigated and compared to a tacrine (9-amino-1,2,3,4-tetrahydroacridine) standard, a known inhibitor of acetylcholinesterase [24]. After short 5 min incubation of the cell lysate with GNDAs (0.5 µM), a remaining 52 -72% antiAChE activity was found (Fig.…”

“…We have searched for a potential cellular target for GNDAs in the SH-SY5Y cell line that is being used as a cellular model of cholinergic phenotype [38] with expression of acetylcholinesterase [39][40][41]. AChE is responsible for the termination of cholinergic transmission (breakdown of acetylcholine) [42,43].…”

Synthesis, Pharmacological Assessment, and Molecular Modeling of Acetylcholinesterase/Butyrylcholinesterase Inhibitors: Effect against Amyloid-β-Induced Neurotoxicity

“…Since some of these compounds can have anticholinesterase activity, we evaluated whether the phenoxyalkylamino-4-phenylnicotinates (2−7), phenoxyalkoxybenzylidenemalononitriles (12,13), pyridonepezils (14−18), and pyrazolo [3,4-b]quinolines (35−37) were able to prevent the increase in AChE activity ( Figure 5) caused by Aβ 1−42 (2 μM incubated for 24 h) in the neuronal cell line SH-SY5Y, which were shown to have AChE. 58 We have previously reported that Aβ peptides are able to increase AChE in cultured neuronal cells. 57 In this study, we also observed that Aβ 1−42 peptide enhanced AChE activity by about 20%.…”