TY - JOUR
T1 - Dynamic regulation of genes involved in mitochondrial DNA replication and transcription during mouse brown fat cell differentiation and recruitment
AU - Murholm, Maria
AU - Dixen, Karen
AU - Qvortrup, Klaus
AU - Hansen, Lillian H L
AU - Amri, Ez-Zoubir
AU - Madsen, Lise
AU - Barbatelli, Giorgio
AU - Quistorff, Bjørn
AU - Hansen, Jacob B
N1 - Keywords: Adipocytes, Brown; Adipocytes, White; Animals; Cell Differentiation; Cell Movement; Cell Nucleus; Cold Temperature; DNA; DNA Replication; DNA, Mitochondrial; DNA-Binding Proteins; Gene Dosage; Gene Expression Regulation; Gene Knockdown Techniques; High Mobility Group Proteins; Mice; Mice, Inbred C57BL; Mitochondria; Nuclear Receptor Co-Repressor 1; Protein Binding; Trans-Activators; Transcription Factors; Transcription, Genetic
PY - 2009
Y1 - 2009
N2 - BACKGROUND: Brown adipocytes are specialised in dissipating energy through adaptive thermogenesis, whereas white adipocytes are specialised in energy storage. These essentially opposite functions are possible for two reasons relating to mitochondria, namely expression of uncoupling protein 1 (UCP1) and a remarkably higher mitochondrial abundance in brown adipocytes. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a comprehensive characterisation of gene expression linked to mitochondrial DNA replication, transcription and function during white and brown fat cell differentiation in vitro as well as in white and brown fat, brown adipose tissue fractions and in selected adipose tissues during cold exposure. We find a massive induction of the majority of such genes during brown adipocyte differentiation and recruitment, e.g. of the mitochondrial transcription factors A (Tfam) and B2 (Tfb2m), whereas only a subset of the same genes were induced during white adipose conversion. In addition, PR domain containing 16 (PRDM16) was found to be expressed at substantially higher levels in brown compared to white pre-adipocytes and adipocytes. We demonstrate that forced expression of Tfam but not Tfb2m in brown adipocyte precursor cells promotes mitochondrial DNA replication, and that silencing of PRDM16 expression during brown fat cell differentiation blunts mitochondrial biogenesis and expression of brown fat cell markers. CONCLUSIONS/SIGNIFICANCE: Using both in vitro and in vivo model systems of white and brown fat cell differentiation, we report a detailed characterisation of gene expression linked to mitochondrial biogenesis and function. We find significant differences in differentiating white and brown adipocytes, which might explain the notable increase in mitochondrial content observed during brown adipose conversion. In addition, our data support a key role of PRDM16 in triggering brown adipocyte differentiation, including mitochondrial biogenesis and expression of UCP1.
AB - BACKGROUND: Brown adipocytes are specialised in dissipating energy through adaptive thermogenesis, whereas white adipocytes are specialised in energy storage. These essentially opposite functions are possible for two reasons relating to mitochondria, namely expression of uncoupling protein 1 (UCP1) and a remarkably higher mitochondrial abundance in brown adipocytes. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a comprehensive characterisation of gene expression linked to mitochondrial DNA replication, transcription and function during white and brown fat cell differentiation in vitro as well as in white and brown fat, brown adipose tissue fractions and in selected adipose tissues during cold exposure. We find a massive induction of the majority of such genes during brown adipocyte differentiation and recruitment, e.g. of the mitochondrial transcription factors A (Tfam) and B2 (Tfb2m), whereas only a subset of the same genes were induced during white adipose conversion. In addition, PR domain containing 16 (PRDM16) was found to be expressed at substantially higher levels in brown compared to white pre-adipocytes and adipocytes. We demonstrate that forced expression of Tfam but not Tfb2m in brown adipocyte precursor cells promotes mitochondrial DNA replication, and that silencing of PRDM16 expression during brown fat cell differentiation blunts mitochondrial biogenesis and expression of brown fat cell markers. CONCLUSIONS/SIGNIFICANCE: Using both in vitro and in vivo model systems of white and brown fat cell differentiation, we report a detailed characterisation of gene expression linked to mitochondrial biogenesis and function. We find significant differences in differentiating white and brown adipocytes, which might explain the notable increase in mitochondrial content observed during brown adipose conversion. In addition, our data support a key role of PRDM16 in triggering brown adipocyte differentiation, including mitochondrial biogenesis and expression of UCP1.
U2 - 10.1371/journal.pone.0008458
DO - 10.1371/journal.pone.0008458
M3 - Journal article
C2 - 20107496
SN - 1932-6203
VL - 4
SP - e8458
JO - PLoS ONE
JF - PLoS ONE
IS - 12
ER -