Ali 2015 Abstract MiPschool Cape Town 2015

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Early gender-related dimorphism in heart and brain mitochondria function and ROS dynamics.

Link:

Ali SS, Abdel-Rahman EA, Khalifa AM, Mahmoud AM, Ali MH (2015)

Event: MiPschool Cape Town 2015

Mitochondrial dysfunction and oxidative stress are proposed as key elements in the pathogenesis of aging, as well as neurological and cardiovascular disorders that occur early in life. Sex differences in free radical homeostasis upon aging have been extensively studied. However, little is known about gender differences in mitochondrial function and dynamics of ROS sources that may develop in young ages and hence contribute to sexual dimorphism in some disorders that occur early in life. We investigated heart and brain mitochondrial respiratory function and ROS production in young (2-5 months) male and female wild-type C57BL6 mice using the Oroboros Oxygraph-2k. Mitochondrial respiratory activity in heart did not significantly differ between genders. However, female brains had an enhanced mitochondrial respiratory activity during state 3, state 4, and maximally uncoupled respiration as compared to male brains. This respiratory activity observed in mitochondria from female heart and brain was associated with lower rates of hydrogen peroxide production in cardiac and neuronal female mitochondria as compared to male. By using two different approaches, we also found that superoxide dismutase (Sod) activity was higher in female brains, suggesting that enhanced antioxidant defenses in female brains contribute to gender differences in ROS levels. Neither protein expression of NADPH oxidases (Nox2 & Nox4) in brain homogenate or synaptosomes, nor the Oroboros determined activity of these enzymes changed between genders. Paradoxically, when Nox-superoxide was assessed in synaptosomes using spin trapping electron paramagnetic resonance spectroscopy, males exhibited higher activity. We conclude that gender differences in mitochondrial function and ROS production occur in young age, and that differences in antioxidant buffering capacity between genders may be primarily responsible for gender differences in brain ROS homeostasis.


O2k-Network Lab: EG Cairo Ali SS


Labels: MiParea: Respiration, Gender 


Organism: Mouse  Tissue;cell: Heart, Nervous system 


Coupling state: LEAK, OXPHOS, ET 

HRR: Oxygraph-2k 


Affiliation

Helmy Inst Med Sc, Zewail City Sc Tech, Egypt. - sameh.ali@zewailcity.edu.eg