title: Muscle induces neuronal expression of acetylcholinesterase in neuron-muscle co-culture: transcriptional regulation mediated by cAMP-dependent signaling.
abstract: Presynaptic motor neuron synthesizes and secretes acetylcholinesterase (AChE) at vertebrate neuromuscular junctions. In order to determine the retrograde role of muscle in regulating the expression of AChE in motor neuron, a chimeric co-culture of NG108-15 cell, a cholinergic cell line that resembles motor neuron, with chick myotube was established to mimic the neuromuscular contact in vitro. A DNA construct of human AChE promoter tagged with luciferase (pAChE-Luc) was stably transfected into NG108-15 cells. The co-culture with myotubes robustly stimulated the promoter activity as well as the endogenous expression of AChE in pAChE-Luc stably transfected NG108-15 cells. Muscle extract derived from chick embryos when applied onto pAChE-Luc-expressing NG108-15 cells induced expressions of AChE promoter and endogenous AChE. The cAMP-responsive element mutation on human AChE promoter blocked the muscle-induced AChE transcriptional activity in cultured NG108-15 cells either in co-culturing with myotube or in applying muscle extract. The accumulation of intracellular cAMP and the phosphorylation of cAMP-responsive element-binding protein in cultured NG108-15 cells were stimulated by applied muscle extract. Part of the muscle-induced signaling was mimicked by application of calcitonin gene-related peptide in cultured NG108-15 cells. These results suggest the muscle-induced neuronal AChE expression in the co-culture is mediated by a cAMP-dependent signaling.
authors.affiliation: Department of Biology and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong, China.
authors.forename: Joy X S
authors.initials: JX
authors.lastname: Jiang
authors.forename: Roy C Y
authors.initials: RC
authors.lastname: Choi
authors.forename: Nina L
authors.initials: NL
authors.lastname: Siow
authors.forename: Henry H C
authors.initials: HH
authors.lastname: Lee
authors.forename: David C C
authors.initials: DC
authors.lastname: Wan
authors.forename: Karl W K
authors.initials: KW
authors.lastname: Tsim
mesh_terms: D000110:Acetylcholinesterase / Q000096:biosynthesis*; D000818:Animals; D002116:Calcitonin / Q000378:metabolism; D002642:Chick Embryo; D018920:Coculture Techniques; D000242:Cyclic AMP / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008957:Models, Genetic; D009046:Motor Neurons / Q000378:metabolism; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D009154:Mutation; D009474:Neurons / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D015398:Signal Transduction; D013395:Sucrose / Q000494:pharmacology; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D011500:Protein Synthesis Inhibitors; D003609:Dactinomycin; D013395:Sucrose; D002116:Calcitonin; D003513:Cycloheximide; D000242:Cyclic AMP; D008156:Luciferases; D000110:Acetylcholinesterase