title: Mitochondrial calcium uptake capacity as a therapeutic target in the R6/2 mouse model of Huntington's disease.
abstract: Huntington's disease (HD) is an incurable autosomal-dominant neurodegenerative disorder initiated by an abnormally expanded polyglutamine domain in the huntingtin protein. It is proposed that abnormal mitochondrial Ca2+ capacity results in an increased susceptibility to mitochondrial permeability transition (MPT) induction that may contribute significantly to HD pathogenesis. The in vivo contribution of these hypothesized defects remains to be elucidated. In this proof-of-principle study, we examined whether increasing mitochondrial Ca2+ capacity could ameliorate the well-characterized phenotype of the R6/2 transgenic mouse model. Mouse models lacking cyclophilin D demonstrate convincingly that cyclophilin D is an essential component and a key regulator of MPT induction. Mitochondria of cyclophilin D knockout mice are particularly resistant to Ca2+ overload. We generated R6/2 mice with normal, reduced or absent cyclophilin D expression and examined the effect of increasing mitochondrial Ca2+ capacity on the behavioral and neuropathological features of the R6/2 model. A predicted outcome of this approach was the finding that cyclophilin D deletion enhanced the R6/2 brain mitochondria Ca2+ capacity significantly. Increased neuronal mitochondrial Ca2+ capacity failed to ameliorate either the behavioral and neuropathological features of R6/2 mice. We found no alterations in body weight changes, lifespan, RotaRod performances, grip strength, overall activity and no significant effect on the neuropathological features of R6/2 mice. The results of this study demonstrate that increasing neuronal mitochondrial Ca2+-buffering capacity is not beneficial in the R6/2 mouse model of HD.
authors.affiliation: Department of Psychiatry, University of Alabama at Birmingham, Birmingham, AL 35294-0017, USA.
authors.forename: Giselle M
authors.initials: GM
authors.lastname: Perry
authors.forename: Sara
authors.initials: S
authors.lastname: Tallaksen-Greene
authors.forename: Ashish
authors.initials: A
authors.lastname: Kumar
authors.forename: Mary Y
authors.initials: MY
authors.lastname: Heng
authors.forename: Andrew
authors.initials: A
authors.lastname: Kneynsberg
authors.forename: Thomas
authors.initials: T
authors.lastname: van Groen
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Detloff
authors.forename: Roger L
authors.initials: RL
authors.lastname: Albin
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lesort
mesh_terms: D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism
chemical_list: D000081406:Peptidyl-Prolyl Isomerase F; C000631446:PPIF protein, mouse; D021983:Cyclophilins; D002118:Calcium