title: Alzheimer's disease-linked presenilin mutation (PS1M146L) induces filamin expression and γ-secretase independent redistribution.
abstract: Presenilin mutations are linked to the early onset familial Alzheimer's disease (FAD) and lead to a range of neuronal changes, indicating that presenilins interact with multiple cellular pathways to regulate neuronal functions. In this report, we demonstrate the effects of FAD-linked presenilin 1 mutation (PS1M146L) on the expression and distribution of filamin, an actin cross-linking protein that interacts with PS1 both physically and genetically. By using immunohistochemical methods, we evaluated hippocampal dentate gyrus for alterations of proteins involved in synaptic plasticity. Among many proteins expressed in the hippocampus, calretinin, glutamic acid decarboxylase (GAD67), parvalbumin, and filamin displayed distinct changes in their expression and/or distribution patterns. Striking anti-filamin immunoreactivity was associated with the polymorphic cells of hilar region only in transgenic mice expressing PS1M146L. In over 20% of the PS1M146L mice, the hippocampus of the left hemisphere displayed more pronounced upregulation of filamin than that of the right hemisphere. Anti-filamin labeled the hilar neurons only after the PS1M146L mice reached after four months of age. Double labeling immunohistochemical analyses showed that anti-filamin labeled neurons partially overlapped with cholecystokinin (CCK), somatostatin, GAD67, parvalbumin, and calretinin immunoreactive neurons. In cultured HEK293 cells, PS1 overexpression resulted in filamin redistribution from near cell peripheries to cytoplasm. Treatment of CHO cells stably expressing PS1 with WPE-III-31C or DAPT, selective γ-secretase inhibitors, did not suppress the effects of PS1 overexpression on filamin. These studies support a γ-secretase-independent role of PS1 in modulation of filamin-mediated actin cytoskeleton.
authors.affiliation: Harriet and John Wooten Laboratory for Alzheimer's Disease and Neurodegenerative Diseases Research, The Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA. luq@ecu.edu
authors.forename: Qun
authors.initials: Q
authors.lastname: Lu
authors.forename: Kai
authors.initials: K
authors.lastname: Ding
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Frosch
authors.forename: Shiloh
authors.initials: S
authors.lastname: Jones
authors.forename: Michael
authors.initials: M
authors.lastname: Wolfe
authors.forename: Weiming
authors.initials: W
authors.lastname: Xia
authors.forename: George W
authors.initials: GW
authors.lastname: Lanford
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism; D053829:Amyloid Precursor Protein Secretases / Q000096:biosynthesis*; D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D003285:Contractile Proteins / Q000096:biosynthesis*; D006224:Cricetinae; D003412:Cricetulus; D018891:Dentate Gyrus / Q000737:chemistry / Q000378:metabolism; D005260:Female; D064448:Filamins; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008840:Microfilament Proteins / Q000096:biosynthesis*; D009154:Mutation / Q000235:genetics*; D053764:Presenilin-1 / Q000235:genetics*; D051381:Rats; D015854:Up-Regulation / Q000235:genetics*
chemical_list: D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D053764:Presenilin-1; D053829:Amyloid Precursor Protein Secretases