Mice lacking inhibitory leptin receptor signals are lean with normal endocrine function
Marie Björnholm, … , Christian Bjørbaek, Martin G. Myers Jr.
Marie Björnholm, … , Christian Bjørbaek, Martin G. Myers Jr.
Published May 1, 2007
Citation Information: J Clin Invest. 2007;117(5):1354-1360. https://doi.org/10.1172/JCI30688.
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Research Article Metabolism

Mice lacking inhibitory leptin receptor signals are lean with normal endocrine function

Abstract

The adipose-derived hormone, leptin, acts via its receptor (LRb) to convey the status of body energy stores to the brain, decreasing feeding and potentiating neuroendocrine energy expenditure. The failure of high levels of leptin in most obese individuals to promote weight loss defines a state of diminished responsiveness to increased leptin, termed leptin resistance. Leptin stimulates the phosphorylation of several tyrosine residues on LRb to mediate leptin action. We homologously replaced LRb in mice with a receptor with a mutation in one of these sites (Tyr985) in order to examine its role in leptin action and signal attenuation in vivo. Mice homozygous for this mutation are neuroendocrinologically normal, but females demonstrate decreased feeding, decreased expression of orexigenic neuropeptides, protection from high-fat diet–induced obesity, and increased leptin sensitivity in a sex-biased manner. Thus, leptin activates autoinhibitory signals via LRb Tyr985 to attenuate the anti-adiposity effects of leptin, especially in females, potentially contributing to leptin insensitivity in obesity.

Authors

Marie Björnholm, Heike Münzberg, Rebecca L. Leshan, Eneida C. Villanueva, Sarah H. Bates, Gwendolyn W. Louis, Justin C. Jones, Ryoko Ishida-Takahashi, Christian Bjørbaek, Martin G. Myers Jr.

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Figure 1

Generation of mice expressing LRbL985.

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Generation of mice expressing LRbL985. (A) Cartoon of si...
(A) Cartoon of signaling by LRb showing the activation of specific signals by individual tyrosine phosphorylation (pY) sites. (B) Targeting strategy for generation of the LeprL985 allele. Shown is the targeting vector containing the LRb-specific exon 18b with the mutation of Tyr985 (which also generates a novel HindIII site) (exon18b-L985) plus Neo and thymidine kinase (TK) cassettes for positive and negative selection, respectively. Recombination in ES cells replaces the wild-type exon 18b with exon 18b-L985 and the Neo cassette, to mediate physiologic expression of the mutant LRb from the endogenous Lepr gene, as previously described (26). (C) Southern blot using a Lepr locus probe, demonstrating correct targeting of the locus in +/+, l/+, and l/l mice. M, marker. (D) qPCR for hypothalamic LRb mRNA expression in +/+ and l/l mice. (E) Hypothalamic detection of STAT3(PY) in +/+ and l/l mice. Age- and sex-matched animals were treated i.p. with vehicle or leptin for 30 minutes. Brains were processed for immunohistochemical detection of STAT3(PY) in the hypothalamus; representative sections showing the ARC and ventromedial hypothalamic nucleus (VMH) are shown. For reference, position of the third cerebral ventricle (3V) is shown. Original magnification, ×20.