Haploinsufficiency of the retinoblastoma protein gene reduces diet-induced obesity, insulin resistance, and hepatosteatosis in mice

TY - JOUR

T1 - Haploinsufficiency of the retinoblastoma protein gene reduces diet-induced obesity, insulin resistance, and hepatosteatosis in mice

AU - Mercader, Josep

AU - Ribot, Joan

AU - Murano, Incoronata

AU - Feddersen, Soren

AU - Cinti, Saverio

AU - Madsen, Lise

AU - Kristiansen, Karsten

AU - Bonet, M Luisa

AU - Palou, Andreu

PY - 2009

Y1 - 2009

N2 - Brown adipose tissue activity dissipates energy as heat, and there is evidence that lack of the retinoblastoma protein (pRb) may favor the development of the brown adipocyte phenotype in adipose cells. In this work we assessed the impact of germ-line haploinsufficiency of the pRb gene (Rb) on the response to high fat diet feeding in mice. Rb(+/-) mice had body weight and adiposity indistinguishable from that of wild-type (Rb(+/+)) littermates when maintained on a standard diet, yet they gained less body weight and body fat after long-term high fat diet feeding, coupled to reduced feed efficiency and increased rectal temperature. Rb haploinsufficiency ameliorated insulin resistance and hepatosteatosis after high fat diet in male mice, in which these disturbances were more marked than in females. Compared to wild-type littermates Rb(+/-) mice fed a high fat diet displayed higher expression of peroxisome proliferator-activated receptor (PPAR) gamma as well as of genes involved in mitochondrial function, cAMP sensitivity, brown adipocyte determination and tissue vascularization in white adipose tissue depots. Furthermore, Rb(+/-) mice exhibited signs of enhanced activation of brown adipose tissue and higher expression levels of PPARalpha in liver and of PPARdelta in skeletal muscle, suggestive of an increased capability for fatty acid oxidation in these tissues. These findings support a role for pRb in modulating whole body energy metabolism and the plasticity of the adipose tissues in vivo, and constitute first evidence that partial deficiency in the Rb gene protects against the development of obesity and associated metabolic disturbances. Key words: brown adipose tissue, white adipose tissue, energy metabolism, genetic animal model.

AB - Brown adipose tissue activity dissipates energy as heat, and there is evidence that lack of the retinoblastoma protein (pRb) may favor the development of the brown adipocyte phenotype in adipose cells. In this work we assessed the impact of germ-line haploinsufficiency of the pRb gene (Rb) on the response to high fat diet feeding in mice. Rb(+/-) mice had body weight and adiposity indistinguishable from that of wild-type (Rb(+/+)) littermates when maintained on a standard diet, yet they gained less body weight and body fat after long-term high fat diet feeding, coupled to reduced feed efficiency and increased rectal temperature. Rb haploinsufficiency ameliorated insulin resistance and hepatosteatosis after high fat diet in male mice, in which these disturbances were more marked than in females. Compared to wild-type littermates Rb(+/-) mice fed a high fat diet displayed higher expression of peroxisome proliferator-activated receptor (PPAR) gamma as well as of genes involved in mitochondrial function, cAMP sensitivity, brown adipocyte determination and tissue vascularization in white adipose tissue depots. Furthermore, Rb(+/-) mice exhibited signs of enhanced activation of brown adipose tissue and higher expression levels of PPARalpha in liver and of PPARdelta in skeletal muscle, suggestive of an increased capability for fatty acid oxidation in these tissues. These findings support a role for pRb in modulating whole body energy metabolism and the plasticity of the adipose tissues in vivo, and constitute first evidence that partial deficiency in the Rb gene protects against the development of obesity and associated metabolic disturbances. Key words: brown adipose tissue, white adipose tissue, energy metabolism, genetic animal model.

U2 - 10.1152/ajpendo.00163.2009

DO - 10.1152/ajpendo.00163.2009

M3 - Journal article

C2 - 19417128

SN - 0193-1849

VL - 297

SP - E184-E193

JO - American Journal of Physiology - Endocrinology and Metabolism

JF - American Journal of Physiology - Endocrinology and Metabolism

IS - 1

ER -