BACKGROUND/OBJECTIVE: Adaptation to the extrauterine environment depends on a switch from glycolysis to catabolism of fatty acids (FA) provided as milk lipids. We sought to learn whether the postnatal induction of muscle FA oxidation in mice could reflect propensity to obesity and to characterize the mechanisms controlling this induction. METHODS: Experiments were conducted using obesity-resistant A/J and obesity-prone C57BL/6J (B6) mice maintained at 30 °C, from 5 to 28 days after birth. At day 10, both A/J and B6 mice with genetic ablation (KO) of α2 subunit of AMP-activated protein kinase (AMPK) were also used. In skeletal muscle, expression of selected genes was determined using quantitative real-time PCR, and AMPK subunits content was evaluated using Western blotting. Activities of both AMPK and pyruvate dehydrogenase (PDH), as well as acylcarnitine levels in the muscle were measured. RESULTS: Acylcarnitine levels and gene expression indicated transient increase in FA oxidation during the first 2 weeks after birth, with a stronger increase in A/J mice. These data correlated with (i) the surge in plasma leptin levels, which peaked at day 10 and was higher in A/J mice, and (ii) relatively low activity of PDH linked with up-regulation of PDH kinase 4 gene (Pdk4) expression in the 10-day-old A/J mice. In contrast with the Pdk4 expression, transient up-regulation of uncoupling protein 3 gene was observed in B6 but not A/J mice. AMPK activity changed during the development, without major differences between A/J and B6 mice. Expression of neither Pdk4 nor other muscle genes was affected by AMPK-KO. CONCLUSIONS: Our results indicate a relatively strong postnatal induction of FA oxidation in skeletal muscle of the obesity-resistant A/J mice. This induction is transient and probably results from suppression of PDH activity, linked with a postnatal surge in plasma leptin levels, independent of AMPK.

• MeSH
• kosterní svaly metabolismus   MeSH
• mastné kyseliny metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• novorozená zvířata MeSH
• obezita metabolismus   MeSH
• oxidace-redukce MeSH
• proteinkinasy aktivované AMP * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• mastné kyseliny MeSH
• Prkaa2 protein, mouse MeSH Prohlížeč
• proteinkinasy aktivované AMP * MeSH

Skeletal muscle wasting and atrophy is one of the more severe clinical impairments resulting from the progression of Huntington's disease (HD). Mitochondrial dysfunction may play a significant role in the etiology of HD, but the specific condition of mitochondria in muscle has not been widely studied during the development of HD. To determine the role of mitochondria in skeletal muscle during the early stages of HD, we analyzed quadriceps femoris muscle from 24-, 36-, 48- and 66-month-old transgenic minipigs that expressed the N-terminal portion of mutated human huntingtin protein (TgHD) and age-matched wild-type (WT) siblings. We found altered ultrastructure of TgHD muscle tissue and mitochondria. There was also significant reduction of activity of citrate synthase and respiratory chain complexes (RCCs) I, II and IV, decreased quantity of oligomycin-sensitivity conferring protein (OSCP) and the E2 subunit of pyruvate dehydrogenase (PDHE2), and differential expression of optic atrophy 1 protein (OPA1) and dynamin-related protein 1 (DRP1) in the skeletal muscle of TgHD minipigs. Statistical analysis identified several parameters that were dependent only on HD status and could therefore be used as potential biomarkers of disease progression. In particular, the reduction of biomarker RCCII subunit SDH30 quantity suggests that similar pathogenic mechanisms underlie disease progression in TgHD minipigs and HD patients. The perturbed biochemical phenotype was detectable in TgHD minipigs prior to the development of ultrastructural changes and locomotor impairment, which become evident at the age of 48 months. Mitochondrial disturbances may contribute to energetic depression in skeletal muscle in HD, which is in concordance with the mobility problems observed in this model.This article has an associated First Person interview with the first author of the paper.

• Klíčová slova
• Biomarkers, Disease development, HD large animal model, Huntington's disease, Mitochondrial function, Skeletal muscle, Ultrastructure,
• MeSH
• DNA metabolismus   MeSH
• energetický metabolismus * MeSH
• geneticky modifikovaná zvířata MeSH
• Huntingtonova nemoc metabolismus   patologie   MeSH
• kosterní svaly metabolismus   ultrastruktura   MeSH
• lidé MeSH
• miniaturní prasata MeSH
• mitochondriální proteiny metabolismus   MeSH
• modely nemocí na zvířatech * MeSH
• mutace MeSH
• oxidativní fosforylace MeSH
• prasata MeSH
• progrese nemoci MeSH
• protein huntingtin genetika   MeSH
• svalové mitochondrie metabolismus   ultrastruktura   MeSH
• tělesná hmotnost MeSH
• transport elektronů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• HTT protein, human MeSH Prohlížeč
• mitochondriální proteiny MeSH
• protein huntingtin MeSH

Huntington's disease (HD) is a monogenic, progressive, neurodegenerative disorder with currently no available treatment. The Libechov transgenic minipig model for HD (TgHD) displays neuroanatomical similarities to humans and exhibits slow disease progression, and is therefore more powerful than available mouse models for the development of therapy. The phenotypic characterization of this model is still ongoing, and it is essential to validate biomarkers to monitor disease progression and intervention. In this study, the behavioral phenotype (cognitive, motor and behavior) of the TgHD model was assessed, along with biomarkers for mitochondrial capacity, oxidative stress, DNA integrity and DNA repair at different ages (24, 36 and 48 months), and compared with age-matched controls. The TgHD minipigs showed progressive accumulation of the mutant huntingtin (mHTT) fragment in brain tissue and exhibited locomotor functional decline at 48 months. Interestingly, this neuropathology progressed without any significant age-dependent changes in any of the other biomarkers assessed. Rather, we observed genotype-specific effects on mitochondrial DNA (mtDNA) damage, mtDNA copy number, 8-oxoguanine DNA glycosylase activity and global level of the epigenetic marker 5-methylcytosine that we believe is indicative of a metabolic alteration that manifests in progressive neuropathology. Peripheral blood mononuclear cells (PBMCs) were relatively spared in the TgHD minipig, probably due to the lack of detectable mHTT. Our data demonstrate that neuropathology in the TgHD model has an age of onset of 48 months, and that oxidative damage and electron transport chain impairment represent later states of the disease that are not optimal for assessing interventions.This article has an associated First Person interview with the first author of the paper.

• Klíčová slova
• DNA damage, DNA repair, HD large animal model, Huntington's disease, Mitochondrial function,
• MeSH
• 8-hydroxy-2'-deoxyguanosin MeSH
• chování zvířat * MeSH
• degenerace nervu patologie   MeSH
• deoxyguanosin analogy a deriváty   metabolismus   MeSH
• energetický metabolismus MeSH
• geneticky modifikovaná zvířata MeSH
• genom MeSH
• Huntingtonova nemoc metabolismus   patologie   MeSH
• lidé MeSH
• miniaturní prasata MeSH
• mitochondrie metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• oprava DNA MeSH
• orgánová specificita MeSH
• poškození DNA MeSH
• prasata MeSH
• protein huntingtin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 8-hydroxy-2'-deoxyguanosin MeSH
• deoxyguanosin MeSH
• protein huntingtin MeSH