Impaired thermogenesis observed in mice with whole-body ablation of peroxisome proliferator-activated receptor-γ coactivator-1β (PGC-1β; officially known as PPARGC1B) may result from impaired brown fat (brown adipose tissue; BAT) function, but other mechanism(s) could be involved. Here, using adipose-specific PGC-1β knockout mice (PGC-1β-AT-KO mice) we aimed to learn whether specific PGC-1β ablation in adipocytes is sufficient to drive cold sensitivity. Indeed, we found that warm-adapted (30°C) mutant mice were relatively sensitive to acute cold exposure (6°C). When these mice were subjected to cold exposure for 7 days (7-day-CE), adrenergic stimulation of their metabolism was impaired, despite similar levels of thermogenic uncoupling protein 1 in BAT in PGC-1β-AT-KO and wild-type mice. Gene expression in BAT of mutant mice suggested a compensatory increase in lipid metabolism to counteract the thermogenic defect. Interestingly, a reduced number of contacts between mitochondria and lipid droplets associated with low levels of L-form of optic atrophy 1 was found in BAT of PGC-1β-AT-KO mice. These genotypic differences were observed in warm-adapted mutant mice, but they were partially masked by 7-day-CE. Collectively, our results suggest a role for PGC-1β in controlling BAT lipid metabolism and thermogenesis. This article has an associated First Person interview with the first author of the paper.

• MeSH
• hnědá tuková tkáň * MeSH
• lidé MeSH
• myši MeSH
• PPARGC1A metabolismus   MeSH
• proteiny vázající RNA metabolismus   MeSH
• termogeneze genetika   MeSH
• transkripční faktory * metabolismus   MeSH
• tukové buňky MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

AIMS/HYPOTHESIS: Intake of n-3 polyunsaturated fatty acids reduces adipose tissue mass, preferentially in the abdomen. The more pronounced effect of marine-derived eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on adiposity, compared with their precursor alpha-linolenic acid, may be mediated by changes in gene expression and metabolism in white fat. METHODS: The effects of EPA/DHA concentrate (6% EPA, 51% DHA) admixed to form two types of high-fat diet were studied in C57BL/6J mice. Oligonucleotide microarrays, cDNA PCR subtraction and quantitative real-time RT-PCR were used to characterise gene expression. Mitochondrial proteins were quantified using immunoblots. Fatty acid oxidation and synthesis were measured in adipose tissue fragments. RESULTS: Expression screens revealed upregulation of genes for mitochondrial proteins, predominantly in epididymal fat when EPA/DHA concentrate was admixed to a semisynthetic high-fat diet rich in alpha-linolenic acid. This was associated with a three-fold stimulation of the expression of genes encoding regulatory factors for mitochondrial biogenesis and oxidative metabolism (peroxisome proliferator-activated receptor gamma coactivator 1 alpha [Ppargc1a, also known as Pgc1alpha] and nuclear respiratory factor-1 [Nrf1] respectively). Expression of genes for carnitine palmitoyltransferase 1A and fatty acid oxidation was increased in epididymal but not subcutaneous fat. In the former depot, lipogenesis was depressed. Similar changes in adipose gene expression were detected after replacement of as little as 15% of lipids in the composite high-fat diet with EPA/DHA concentrate, while the development of obesity was reduced. The expression of Ppargc1a and Nrf1 was also stimulated by n-3 polyunsaturated fatty acids in 3T3-L1 cells. CONCLUSIONS/INTERPRETATION: The anti-adipogenic effect of EPA/DHA may involve a metabolic switch in adipocytes that includes enhancement of beta-oxidation and upregulation of mitochondrial biogenesis.

• MeSH
• epididymis metabolismus   účinky léků   MeSH
• faktor 1 související s NF-E2 genetika   účinky léků   MeSH
• karnitin-O-palmitoyltransferasa genetika   účinky léků   MeSH
• kultivované buňky MeSH
• kyselina alfa-linolenová farmakologie   MeSH
• kyselina eikosapentaenová farmakologie   MeSH
• kyseliny dokosahexaenové farmakologie   MeSH
• lipogeneze účinky záření   MeSH
• mitochondriální proteiny metabolismus   účinky léků   MeSH
• mitochondrie metabolismus   účinky léků   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nenasycené mastné kyseliny farmakologie   izolace a purifikace   metabolismus   MeSH
• obezita prevence a kontrola   MeSH
• oxidace-redukce MeSH
• podkožní tuk metabolismus   účinky léků   MeSH
• regulace genové exprese účinky záření   MeSH
• rybí oleje chemie   MeSH
• trans-aktivátory genetika   účinky léků   MeSH
• tuková tkáň metabolismus   účinky léků   MeSH
• tukové buňky metabolismus   účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• srovnávací studie MeSH