title: Alpha-synuclein alters Notch-1 expression and neurogenesis in mouse embryonic stem cells and in the hippocampus of transgenic mice.
abstract: Altered expression and mutations in alpha-synuclein (alpha-syn) have been linked to Parkinson's disease (PD) and related disorders. The neurological alterations in PD patients have been associated with degeneration of dopaminergic cells and other neuronal populations. Moreover, recent studies in murine models have shown that alterations in neurogenesis might also contribute to the neurodegenerative phenotype. However, the mechanisms involved and the effects of alpha-syn expression on neurogenesis are not yet clear. To this end, murine embryonic stem (mES) cells were infected with lentiviral (LV) vectors expressing wild-type (WT) and mutant alpha-syn. Compared with mES cells infected with LV-green fluorescent protein (GFP), cells expressing WT and mutant alpha-syn showed reduced proliferation as indicated by lower 5-bromo-2'-deoxyuridine uptake, increased apoptosis, and reduced expression of neuronal markers such as neuron specific enolase and beta-III tubulin. The alterations in neurogenesis in alpha-syn-expressing mES cells were accompanied by a reduction in Notch-1 and Hairy and enhancer of split-5 (Hes-5) mRNA and protein levels. Moreover, levels of total Notch-1 and Notch intracellular domain (NICD) were lower in mES cells expressing WT and mutant alpha-syn compared with GFP controls. The reduced survival of alpha-syn-expressing mES cells was reverted by overexpressing constitutively active NICD. Similarly, in alpha-syn transgenic mice, the alterations in neurogenesis in the hippocampal subgranular zone were accompanied by decreased Notch-1, NICD, and Hes-5 expression. Together, these results suggest that accumulation of alpha-syn might impair survival of NPCs by interfering with the Notch signaling pathway. Similar mechanisms could be at play in PD and Lewy body disease.
authors.affiliation: Departments of Neurosciences, University of California, San Diego, La Jolla, California 92093-0624, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Crews
authors.forename: Hideya
authors.initials: H
authors.lastname: Mizuno
authors.forename: Paula
authors.initials: P
authors.lastname: Desplats
authors.forename: Edward
authors.initials: E
authors.lastname: Rockenstein
authors.forename: Anthony
authors.initials: A
authors.lastname: Adame
authors.forename: Christina
authors.initials: C
authors.lastname: Patrick
authors.forename: Beate
authors.initials: B
authors.lastname: Winner
authors.forename: Juergen
authors.initials: J
authors.lastname: Winkler
authors.forename: Eliezer
authors.initials: E
authors.lastname: Masliah
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D015536:Down-Regulation / Q000502:physiology*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006624:Hippocampus / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D051881:Receptor, Notch1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D051844:alpha-Synuclein / Q000235:genetics / Q000502:physiology*
chemical_list: C497762:Notch1 protein, mouse; D051881:Receptor, Notch1; D051844:alpha-Synuclein