Pharaoh 2021 JCSM Rapid Commun

From Bioblast
Publications in the MiPMap
Pharaoh G, Brown J, Ranjit R, Ungvari Z, Van Remmen H (2021) Reduced adenosine diphosphate sensitivity in skeletal muscle mitochondria increases reactive oxygen species production in mouse models of aging and oxidative stress but not denervation.

Β» JCSM Rapid Commun 4:75-89. PMID: 36159599 Open Access

Pharaoh Gavin,  Brown Jacob, Ranjit Rojina,  Ungvari Zoltan,  Van Remmen Holly (2021) JCSM Rapid Commun

Abstract: Mitochondrial bioenergetics are sensitive to adenosine diphosphate (ADP) concentration. Reactive oxygen species (ROS) production and respiration [oxygen consumption rate (OCR)] are altered at physiological ADP concentrations (i.e. ADP insensitivity) in aged human muscle. Here, we investigate ADP sensitivity in mouse muscle mitochondria.

We measured OCR and ROS production in permeabilized gastrocnemius fibres using an ADP titration protocol and the Oroboros O2k respirometer and fluorometer. We measured changes in ADP sensitivity in muscle from mice at different ages, after sciatic nerve transection (denervation), and in response to increased oxidative stress (Sod1-/- mice). Further, we asked whether the mitochondrial-targeted peptide SS-31 can modulate ADP insensitivity and contractile function in the Sod1-/- mouse model.

Reduced ADP sensitivity is associated with increases in mitochondrial ROS production in aged (62%) and Sod1-/- (33%) mice. The maximal capacity to produce ROS does not increase with age, and there is no effect of age on ADP sensitivity for OCR in mouse gastrocnemii. Denervation does not induce ADP insensitivity for either ROS generation or OCR. Treatment of Sod1-/- mice with SS-31 increases ADP sensitivity for both OCR and ROS, decreases maximal ROS production (~40%), and improves resistance to muscle fatigue.

Adenosine diphosphate sensitivity for ROS production decreases in aged mouse gastrocnemius muscle fibres, although aged mice do not exhibit a difference in OCR. Denervation does not induce ADP insensitivity; however, insensitivity to ADP is induced in a model of oxidative stress. ADP insensitivity could contribute to muscle fatigue, and SS-31 may be the first drug capable of targeting this aging phenotype. β€’ Keywords: ADP sensitivity, Mitochondria, Oroboros O2k respirometry and fluorometry, Reactive oxygen species (ROS) production, Sarcopenia β€’ Bioblast editor: Plangger M β€’ O2k-Network Lab: US OK Oklahoma City Van Remmen H

Labels: MiParea: Respiration, Genetic knockout;overexpression 

Organism: Mouse  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 

Regulation: ADP  Coupling state: LEAK, OXPHOS  Pathway: N, S, CIV, NS, ROX  HRR: Oxygraph-2k, O2k-Fluorometer 

2023-01, AmR 

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