Abstract
Introduction
Mice models of Wfs1 deficiency allow to study the mechanisms of human Wolfram syndrome. Our aim was to assess the changes in mitochondrial proteins and function in muscles of wfs1‐deficient mice.
Materials and methods
Samples of heart, m. soleus and m. rectus femoris of wfs1‐deficient and wild‐type mice. LFQ intensity of proteins was evaluated by nano‐LC‐MS/MS analysis of muscle homogenates, mRNA levels of uncoupler proteins, UCP2 and UCP3, by real‐time PCR method, and citrate synthase activity was determined spectrophotometrically. Mitochondrial function was assayed by high‐resolution oxygraphy of permeabilized muscle fibres.
Results
Compared with controls, there was no change in proton leak and citrate synthase activity in the wfs1‐deficient heart and m. soleus, but in m. rectus femoris 16.1‐fold (P<0.002) and 1.46‐fold (P<0.05) increases were found respectively. However, oxidative phosphorylation did not change in any muscle group. UCP2 mRNA level was in wfs1‐deficient m. rectus femoris 2.6 times (P<0.05) higher than in wild‐type muscle. UCP3 expression was one order of magnitude lesser than UCP2 and did not differ in muscle groups. The amounts of mitochondrial pyruvate dehydrogenase E1 component subunit alpha and mitochondrial succinate dehydrogenase iron sulphur subunit were in m. rectus femoris, compared with the wild type, respectively, 1.69 (P<0.005) and 2.08 times (P<0.0002) larger.
Conclusion
Wfs1‐deficient mice are characterized by a larger amount and activity of mitochondrial proteins in m. rectus femoris; the proton leak in this muscle was increased probably due to a larger amount of UCP2.