title: The higher susceptibility of congenital analbuminemic rats to Ca2+-induced mitochondrial permeability transition is associated with the increased expression of cyclophilin D and nitrosothiol depletion.
abstract: Congenital analbuminemia is a rare autosomal recessive disorder characterized by a trace level of albumin in blood plasma and mild clinical symptoms. Analbuminemic patients generally present associated abnormalities, among which dyslipidemia is a hallmark. In this study, we show that mitochondria isolated from different tissues (liver, heart and brain) from 3-month-old analbuminemic rats (NAR) present a higher susceptibility to Ca(2+)-induced mitochondrial permeability transition (MPT), as assessed by either Ca(2+)-induced mitochondrial swelling, dissipation of membrane potential or mitochondrial Ca(2+) release. The Ca(2+) retention capacity of the liver mitochondria isolated from 3-month-old NAR was about 50% that of the control. Interestingly, the assessment of this variable in 21-day-old NAR indicated that the mitochondrial Ca(2+) retention capacity was preserved at this age, as compared to age-matched controls, which indicates that a reduced capacity for mitochondrial Ca(2+) retention is not a constitutive feature. The search for putative mediators of MPT sensitization in NAR revealed a 20% decrease in mitochondrial nitrosothiol content and a 30% increase in cyclophilin D expression. However, the evaluation of other variables related to mitochondrial redox status showed similar results between the controls and NAR, i.e., namely the contents of reduced mitochondrial membrane protein thiol groups and total glutathione, H(2)O(2) release rate, and NAD(P)H reduced state. We conclude that the higher expression of cyclophilin D, a major component of the MPT pore, and decreased nitrosothiol content in NAR mitochondria may underlie MPT sensitization in these animals.
authors.affiliation: Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Tiago R
authors.initials: TR
authors.lastname: Figueira
authors.forename: Roger F
authors.initials: RF
authors.lastname: Castilho
authors.forename: Angela
authors.initials: A
authors.lastname: Saito
authors.forename: Helena C F
authors.initials: HC
authors.lastname: Oliveira
authors.forename: Anibal E
authors.initials: AE
authors.lastname: Vercesi
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D002118:Calcium; D000013:Congenital Abnormalities / Q000378:metabolism*; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008297:Male; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism*; D008933:Mitochondrial Swelling; D018384:Oxidative Stress; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D026403:S-Nitrosothiols / Q000378:metabolism*; D012709:Serum Albumin / Q000172:deficiency*
chemical_list: D000081406:Peptidyl-Prolyl Isomerase F; D017382:Reactive Oxygen Species; D026403:S-Nitrosothiols; D012709:Serum Albumin; D021983:Cyclophilins; D002118:Calcium