title: Differential role of Presenilin-1 and -2 on mitochondrial membrane potential and oxygen consumption in mouse embryonic fibroblasts.
abstract: Increasing evidence indicates that mitochondrial alterations contribute to the neuronal death in Alzheimer's disease (AD). Presenilin 1 (PS1) and Presenilin 2 (PS2) mutations have been shown to sensitize cells to apoptosis by mechanisms suggested to involve impaired mitochondrial function. We have previously detected active gamma-secretase complexes in mitochondria. We investigated the impact of PS/gamma-secretase on mitochondrial function using mouse embryonal fibroblasts derived from wild-type, PS1-/-, PS2-/- and PS double knock-out (PSKO) embryos. Measurements of mitochondrial membrane potential (DeltaPsim) showed a higher percentage of fully functional mitochondria in PS1-/- and PSwt as compared to PS2-/- and PSKO cells. This result was evident both in whole cell preparations and in isolated mitochondria. Interestingly, pre-treatment of isolated mitochondria with the gamma-secretase inhibitor L-685,458 resulted in a decreased population of mitochondria with high DeltaPsim in PSwt and PS1-/- cells, indicating that PS2/gamma-secretase activity can modify DeltaPsim. PS2-/- cells showed a significantly lower basal respiratory rate as compared to other cell lines. However, all cell lines demonstrated competent bioenergetic function. These data point toward a specific role of PS2/gamma-secretase activity for proper mitochondrial function and indicate interplay between PS1 and PS2 in mitochondrial functionality.
authors.affiliation: Department of Neurobiology, Karolinska Institutet Dainippon Sumitomo Pharmaceuticals Alzheimer Center, Caring Sciences and Society, Novum, Huddinge, Sweden. homira.behbahani@ki.se
authors.forename: Homira
authors.initials: H
authors.lastname: Behbahani
authors.forename: Irina G
authors.initials: IG
authors.lastname: Shabalina
authors.forename: Birgitta
authors.initials: B
authors.lastname: Wiehager
authors.forename: Hérnan
authors.initials: H
authors.lastname: Concha
authors.forename: Kjell
authors.initials: K
authors.lastname: Hultenby
authors.forename: Natasa
authors.initials: N
authors.lastname: Petrovic
authors.forename: Jan
authors.initials: J
authors.lastname: Nedergaard
authors.forename: Bengt
authors.initials: B
authors.lastname: Winblad
authors.forename: Richard F
authors.initials: RF
authors.lastname: Cowburn
authors.forename: Maria
authors.initials: M
authors.lastname: Ankarcrona
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism; D002232:Carbocyanines / Q000378:metabolism; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D005434:Flow Cytometry / Q000379:methods; D007476:Ionophores / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000502:physiology*; D009840:Oligomycins / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology*; D053764:Presenilin-1; D053766:Presenilin-2
chemical_list: D001562:Benzimidazoles; D002232:Carbocyanines; D004791:Enzyme Inhibitors; D007476:Ionophores; D008565:Membrane Proteins; D009840:Oligomycins; D053764:Presenilin-1; D053766:Presenilin-2; C068624:5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate