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Neuronal overexpression of insulin receptor substrate 2 leads to increased fat mass, insulin resistance, and glucose intolerance during aging.
Zemva, J; Udelhoven, M; Moll, L; Freude, S; Stöhr, O; Brönneke, H S; Drake, R B; Krone, W; Schubert, M.
Afiliación
  • Zemva J; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
Age (Dordr) ; 35(5): 1881-97, 2013 Oct.
Article en En | MEDLINE | ID: mdl-23160735
The insulin receptor substrates (IRS) are adapter proteins mediating insulin's and IGF1's intracellular effects. Recent data suggest that IRS2 in the central nervous system (CNS) is involved in regulating fuel metabolism as well as memory formation. The present study aims to specifically define the role of chronically increased IRS2-mediated signal transduction in the CNS. We generated transgenic mice overexpressing IRS2 specifically in neurons (nIRS2 (tg)) and analyzed these in respect to energy metabolism, learning, and memory. Western blot (WB) analysis of nIRS2 (tg) brain lysates revealed increased IRS2 downstream signaling. Histopathological investigation of nIRS2 (tg) mice proved unaltered brain development and structure. Interestingly, nIRS2 (tg) mice showed decreased voluntary locomotoric activity during dark phase accompanied with decreased energy expenditure (EE) leading to increased fat mass. Accordingly, nIRS2 (tg) mice develop insulin resistance and glucose intolerance during aging. Exploratory behavior, motor function as well as food and water intake were unchanged in nIRS2 (tg) mice. Surprisingly, increased IRS2-mediated signals did not change spatial working memory in the T-maze task. Since FoxO1 is a key mediator of IRS2-transmitted signals, we additionally generated mice expressing a dominant negative mutant of FoxO1 (FoxO1DN) specifically in neurons. This mutant mimics the effect of increased IRS2 signaling on FoxO-mediated transcription. Interestingly, the phenotype observed in nIRS2 (tg) mice was not present in FoxO1DN mice. Therefore, increased neuronal IRS2 signaling causes decreased locomotoric activity in the presence of unaltered exploratory behavior and motor coordination that might lead to increased fat mass, insulin resistance, and glucose intolerance during aging independent of FoxO1-mediated transcription.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Encéfalo / Envejecimiento / ADN / Resistencia a la Insulina / Intolerancia a la Glucosa / Regulación del Desarrollo de la Expresión Génica / Proteínas Sustrato del Receptor de Insulina Límite: Animals Idioma: En Revista: Age (Dordr) Año: 2013 Tipo del documento: Article País de afiliación: Alemania Pais de publicación: Países Bajos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Encéfalo / Envejecimiento / ADN / Resistencia a la Insulina / Intolerancia a la Glucosa / Regulación del Desarrollo de la Expresión Génica / Proteínas Sustrato del Receptor de Insulina Límite: Animals Idioma: En Revista: Age (Dordr) Año: 2013 Tipo del documento: Article País de afiliación: Alemania Pais de publicación: Países Bajos