title: Cellular program controlling the recovery of adipose tissue mass: An in vivo imaging approach.
abstract: The cellular program responsible for the restoration of adipose tissue mass after weight loss is largely uncharacterized. Leptin mRNA levels are highly correlated with adipose tissue mass, and leptin expression can thus be used as a surrogate for changes in the amount of adipose tissue. To further study the responses of adipocytes to changes in weight, we created a transgenic mouse expressing the luciferase reporter gene under the control of leptin regulatory sequences, which allows noninvasive imaging of the leptin expression of mice in vivo. We used these animals to show that weight loss induced by fasting or leptin treatment results in the retention of lipid-depleted adipocytes in adipose depots. To further study the cellular response to weight regain after leptin treatment, a leptin withdrawal protocol was used to induce a state of acute leptin deficiency in wild type mice. Acute leptin deficiency led to the transient deposition of large amounts of glycogen within pre-existing, lipid-depleted adipocytes. This was followed by rapid reaccumulation of lipid. Transcriptional profiling revealed that this cellular response was associated with induction of mRNAs for the entire pathway of enzymes necessary to convert glucose into acetyl-CoA and glycerol, key substrates for the synthesis of triglycerides.
authors.affiliation: Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Kivanç
authors.initials: K
authors.lastname: Birsoy
authors.forename: Alexander
authors.initials: A
authors.lastname: Soukas
authors.forename: Javier
authors.initials: J
authors.lastname: Torrens
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ceccarini
authors.forename: Jason
authors.initials: J
authors.lastname: Montez
authors.forename: Margherita
authors.initials: M
authors.lastname: Maffei
authors.forename: Paul
authors.initials: P
authors.lastname: Cohen
authors.forename: Gulnorakhon
authors.initials: G
authors.lastname: Fayzikhodjaeva
authors.forename: Agnes
authors.initials: A
authors.lastname: Viale
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Socci
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Friedman