Retinoblastoma protein functions as a molecular switch determining white versus brown adipocyte differentiation.

TY - JOUR

T1 - Retinoblastoma protein functions as a molecular switch determining white versus brown adipocyte differentiation.

AU - Hansen, Jacob B

AU - Jørgensen, Claus

AU - Petersen, Rasmus K

AU - Hallenborg, Philip

AU - De Matteis, Rita

AU - Bøye, Hans A

AU - Petrovic, Natasa

AU - Enerbäck, Sven

AU - Nedergaard, Jan

AU - Cinti, Saverio

AU - te Riele, Hein

AU - Kristiansen, Karsten

N1 - Keywords: Adipocytes; Adipose Tissue, Brown; Animals; Antigens, Polyomavirus Transforming; Carrier Proteins; Cell Differentiation; Cyclic AMP; Fibroblasts; Ion Channels; Membrane Proteins; Mice; Mice, Inbred C57BL; Mitochondrial Proteins; Rats; Rats, Sprague-Dawley; Retinoblastoma Protein; Simian virus 40

PY - 2004

Y1 - 2004

N2 - Adipocyte precursor cells give raise to two major cell populations with different physiological roles: white and brown adipocytes. Here we demonstrate that the retinoblastoma protein (pRB) regulates white vs. brown adipocyte differentiation. Functional inactivation of pRB in wild-type mouse embryo fibroblasts (MEFs) and white preadipocytes by expression of simian virus 40 large T antigen results in the expression of the brown fat-specific uncoupling protein 1 (UCP-1) in the adipose state. Retinoblastoma gene-deficient (Rb-/-) MEFs and stem cells, but not the corresponding wild-type cells, differentiate into adipocytes with a gene expression pattern and mitochondria content resembling brown adipose tissue. pRB-deficient MEFs exhibit an increased expression of the Forkhead transcription factor Foxc2 and its target gene cAMP-dependent protein kinase regulatory subunit RIalpha, resulting in increased cAMP sensitivity. Suppression of cAMP-dependent protein kinase activity in Rb(-/-)MEFs blocked the brown adipocyte-like gene expression pattern without affecting differentiation per se. Immunohistochemical studies revealed that pRB is present in the nuclei of white but not brown adipocyte precursor cells at a developmental stage where both cell types begin to accumulate lipid and brown adipocytes express UCP-1. Furthermore, pRB rapidly undergoes phosphorylation upon cold-induced neodifferentiation and up-regulation of UCP-1 expression in brown adipose tissue. Finally, down-regulation of pRB expression accompanies transdifferentiation of white into brown adipocytes in response to beta3-adrenergic receptor agonist treatment. We propose that pRB acts as a molecular switch determining white vs. brown adipogenesis, suggesting a previously uncharacterized function of this key cell cycle regulator in adipocyte lineage commitment and differentiation.

AB - Adipocyte precursor cells give raise to two major cell populations with different physiological roles: white and brown adipocytes. Here we demonstrate that the retinoblastoma protein (pRB) regulates white vs. brown adipocyte differentiation. Functional inactivation of pRB in wild-type mouse embryo fibroblasts (MEFs) and white preadipocytes by expression of simian virus 40 large T antigen results in the expression of the brown fat-specific uncoupling protein 1 (UCP-1) in the adipose state. Retinoblastoma gene-deficient (Rb-/-) MEFs and stem cells, but not the corresponding wild-type cells, differentiate into adipocytes with a gene expression pattern and mitochondria content resembling brown adipose tissue. pRB-deficient MEFs exhibit an increased expression of the Forkhead transcription factor Foxc2 and its target gene cAMP-dependent protein kinase regulatory subunit RIalpha, resulting in increased cAMP sensitivity. Suppression of cAMP-dependent protein kinase activity in Rb(-/-)MEFs blocked the brown adipocyte-like gene expression pattern without affecting differentiation per se. Immunohistochemical studies revealed that pRB is present in the nuclei of white but not brown adipocyte precursor cells at a developmental stage where both cell types begin to accumulate lipid and brown adipocytes express UCP-1. Furthermore, pRB rapidly undergoes phosphorylation upon cold-induced neodifferentiation and up-regulation of UCP-1 expression in brown adipose tissue. Finally, down-regulation of pRB expression accompanies transdifferentiation of white into brown adipocytes in response to beta3-adrenergic receptor agonist treatment. We propose that pRB acts as a molecular switch determining white vs. brown adipogenesis, suggesting a previously uncharacterized function of this key cell cycle regulator in adipocyte lineage commitment and differentiation.

U2 - 10.1073/pnas.0301964101

DO - 10.1073/pnas.0301964101

M3 - Journal article

C2 - 15024128

SN - 0027-8424

VL - 101

SP - 4112

EP - 4117

JO - Proceedings of the National Academy of Science of the United States of America

JF - Proceedings of the National Academy of Science of the United States of America

IS - 12

ER -