Loss of white adipose tissue (WAT), resistance to high fat diet-induced obesity, and ectopic Ucp1 in WAT of Ate1-deficient mice.

Abstract

<p>(A–C) Visceral fat content of Ate1-containing mice. Shown here are representative examples of Ate1-containing (<i>Ate1^flox/+</i>;<i>CaggCreER</i>) (A) and <i>Ate1^flox/−</i> (B)) and Ate1-deficient (<i>Ate1^flox/−</i>;<i>CaggCreER</i> (C)) mice 37 days after TM-treatment. Note the loss of both visceral fat (large white arrow in A and B) and fat surrounding the kidney (small white arrows in A and B) in an Ate1-deficient mouse (C). (D) Hematoxylin/eosin staining of a 10-µm section of white adipose tissue (WAT) harvested from an Ate1-containing mouse (TM-treated <i>Ate1^flox/+</i>;<i>CaggCreER</i>). The bar denotes 100 µm. (E) Same as in D except that WAT was from an Ate1-deficient mouse (TM-treated <i>Ate1^flox/−</i>;<i>CaggCreER</i>). (F) Average weights of TM-treated Ate1-containing (n = 12; black curve) and Ate1-deficient (n = 11; red curve) mice as a function of time after the beginning of <i>ad libitum</i> high-fat diet. Weights were measured at weekly intervals for 10 weeks. Error bars indicate ±SD. (G) Comparisons, by immunoblotting, of Ucp1 protein levels in extracts from brown adipose tissue (BAT) (lanes 1 and 2) and WAT (lanes 3 through 6) from <i>Ate1^+/−</i> and <i>Ate1^−/−</i> mice 46 days (lanes 1 and 2) or ∼1 year (lanes 3–6) after TM treatment. Specific genotypes were as follows (genotypes after TM treatment are indicated in parentheses here, and also on top of the gel): lane 1, <i>Ate1^flox/−</i> (+/−); lane 2, <i>Ate1^flox/−</i>;<i>CaggCreER</i> (−/−); lane 3, <i>Ate1^flox/−</i>;<i>CaggCreER</i> (−/−); lane 4, <i>Ate1^flox/−</i> (+/−); lane 5, <i>Ate1^flox/−</i>;<i>CaggCreER</i> (−/−); lane 6, <i>Ate1^flox/+</i>;<i>CaggCreER</i> (+/−). Note abnormally high expression of Ucp1 in WAT of Ate1-deficient mice (lanes 3 and 5). An asterisk denotes a protein in WAT that cross-reacts with anti-Ucp1 antibody. (H) RT-PCR analyses of leptin and <i>Ucp1</i> mRNA levels in BAT (lanes 1–4) and WAT (lanes 5–8) of Ate1-containing (denoted as “+/−”; lanes 2, 4, 6, and 8) and Ate1-deficient (denoted as “−/−”; lanes 1, 3, 5, and 7) mice ∼1 year after TM treatment. Specific genotypes: lanes 1 and 5, <i>Ate1^flox/flox</i>;<i>CaggCreER</i> (−/−); lanes 2 and 6, <i>Ate1^flox/+</i>;<i>CaggCreER</i> (+/−); lanes 3 and 5, <i>Ate1^flox/flox</i>;<i>CaggCreER</i> (−/−); lanes 4 and 8, <i>Ate1^flox/−</i> (+/−). (I) RT-PCR analyses of <i>Ucp1</i> and <i>Ucp2</i> mRNA levels in BAT, liver, muscle, and WAT of an <i>Ate1^flox/+</i> mouse (denoted as “+/−”) and an <i>Ate1^flox/−</i>;<i>CaggCreER</i> mouse (denoted as “−/−”)∼1 year after TM treatment.</p