Adipocyte-specific mTORC2 deficiency impairs BAT and iWAT thermogenic capacity without affecting glucose uptake and energy expenditure in cold-acclimated mice.
Érique CastroThayna S VieiraTiago E OliveiraMilene Ortiz-SilvaMaynara L AndradeCaroline A TomazelliAlbert S PeixotoCleyton R SobrinhoMayara F MorenoGustavo R GilioRafael J MoreiraRaphael C GuimarãesLuiz A PerandiniPatricia ChiminPatricia ReckziegelEduardo H MorettiAlexandre A SteinerMathieu LaplanteWilliam T FestucciaPublished in: American journal of physiology. Endocrinology and metabolism (2021)
Deletion of mechanistic target of rapamycin complex 2 (mTORC2) essential component rapamycin insensitive companion of mTOR (Rictor) by a Cre recombinase under control of the broad, nonadipocyte-specific aP2/FABP4 promoter impairs thermoregulation and brown adipose tissue (BAT) glucose uptake on acute cold exposure. We investigated herein whether adipocyte-specific mTORC2 deficiency affects BAT and inguinal white adipose tissue (iWAT) signaling, metabolism, and thermogenesis in cold-acclimated mice. For this, 8-wk-old male mice bearing Rictor deletion and therefore mTORC2 deficiency in adipocytes (adiponectin-Cre) and littermates controls were either kept at thermoneutrality (30 ± 1°C) or cold-acclimated (10 ± 1°C) for 14 days and evaluated for BAT and iWAT signaling, metabolism, and thermogenesis. Cold acclimation inhibited mTORC2 in BAT and iWAT, but its residual activity is still required for the cold-induced increases in BAT adipocyte number, total UCP-1 content and mRNA levels of proliferation markers Ki67 and cyclin 1 D, and de novo lipogenesis enzymes ATP-citrate lyase and acetyl-CoA carboxylase. In iWAT, mTORC2 residual activity is partially required for the cold-induced increases in multilocular adipocytes, mitochondrial mass, and uncoupling protein 1 (UCP-1) content. Conversely, BAT mTORC1 activity and BAT and iWAT glucose uptake were upregulated by cold independently of mTORC2. Noteworthy, the impairment in BAT and iWAT total UCP-1 content and thermogenic capacity induced by adipocyte mTORC2 deficiency had no major impact on whole body energy expenditure in cold-acclimated mice due to a compensatory activation of muscle shivering. In conclusion, adipocyte mTORC2 deficiency impairs, through different mechanisms, BAT and iWAT total UCP-1 content and thermogenic capacity in cold-acclimated mice, without affecting glucose uptake and whole body energy expenditure.NEW & NOTEWORTHY BAT and iWAT mTORC2 is inhibited by cold acclimation, but its residual activity is required for cold-induced increases in total UCP-1 content and thermogenic capacity, but not glucose uptake and mTORC1 activity. The impaired BAT and iWAT total UCP-1 content and thermogenic capacity induced by adipocyte mTORC2 deficiency are compensated by activation of muscle shivering in cold-acclimated mice.
Keyphrases
- adipose tissue
- insulin resistance
- high fat diet induced
- high fat diet
- fatty acid
- prostate cancer
- metabolic syndrome
- type diabetes
- skeletal muscle
- blood glucose
- oxidative stress
- drug induced
- radiation therapy
- diabetic rats
- small molecule
- signaling pathway
- intensive care unit
- cell cycle
- hepatitis b virus
- binding protein
- lymph node
- cell proliferation
- liver failure
- endothelial cells
- locally advanced
- acute respiratory distress syndrome
- aortic dissection
- respiratory failure
- rectal cancer
- high speed