Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Aug 21;454(7207):961-7.
doi: 10.1038/nature07182.

PRDM16 Controls a Brown Fat/Skeletal Muscle Switch

Affiliations
Free PMC article

PRDM16 Controls a Brown Fat/Skeletal Muscle Switch

Patrick Seale et al. Nature. .
Free PMC article

Abstract

Brown fat can increase energy expenditure and protect against obesity through a specialized program of uncoupled respiration. Here we show by in vivo fate mapping that brown, but not white, fat cells arise from precursors that express Myf5, a gene previously thought to be expressed only in the myogenic lineage. We also demonstrate that the transcriptional regulator PRDM16 (PRD1-BF1-RIZ1 homologous domain containing 16) controls a bidirectional cell fate switch between skeletal myoblasts and brown fat cells. Loss of PRDM16 from brown fat precursors causes a loss of brown fat characteristics and promotes muscle differentiation. Conversely, ectopic expression of PRDM16 in myoblasts induces their differentiation into brown fat cells. PRDM16 stimulates brown adipogenesis by binding to PPAR-gamma (peroxisome-proliferator-activated receptor-gamma) and activating its transcriptional function. Finally, Prdm16-deficient brown fat displays an abnormal morphology, reduced thermogenic gene expression and elevated expression of muscle-specific genes. Taken together, these data indicate that PRDM16 specifies the brown fat lineage from a progenitor that expresses myoblast markers and is not involved in white adipogenesis.

Figures

Fig. 1
Fig. 1. Knockdown of PRDM16 in primary brown fat cells induces skeletal myogenesis
(a) Western blot analysis for PRDM16 in primary brown fat cell cultures transduced with adenovirus expressing shRNA targeted to PRDM16 or a scrambled (SCR) control shRNA. (b) These cultures were visualized by phase contrast microscopy and by GFP fluorescence. (c) Immunocytochemistry for skeletal Myosin Heavy Chain (MyHC) expression. (d) Gene expression at day 4 of adipocyte differentiation including BAT-selective and skeletal muscle-specific genes (as indicated). C2C12 myotubes were also assayed for their expression of muscle-specific genes (n=3, error bars represent ± SD; *p<0.05, **p<0.01).
Fig. 2
Fig. 2. Brown fat and skeletal muscle arise from myf5-expressing precursors
(a)myf5-cre mice were intercrossed with indicator mice that have a YFP gene integrated into the rosa26 locus downstream of a floxed transcriptional stop sequence (R26R3-YFP). Expression of Cre recombinase excises the stop sequence to irreversibly activate YFP expression. (b) Immunohistochemistry to detect YFP (GFP) expression in skeletal muscle (sk. musc), BAT and WAT from control (myf5-cre negative) and myf5-cre:R26R3-YFP mice. (c) Real-time PCR analysis of YFP mRNA levels in: liver; gluteal (glut), inguinal (ing) and epididymal (epid) WAT; skeletal muscle (skM) and BAT (n= 4/group; error bars are ± SEM; **p<0.01). (d) UCP1 and GFP expression in WAT and BAT from CL316, 243 treated myf5-cre:R26R3-YFP mice.
Fig. 3
Fig. 3. PRDM16 stimulates brown adipocyte differentiation in skeletal myoblasts
(a–d) C2C12 myoblasts expressing retroviral PRDM16 or vector control (ctl) were stained with Oil-Red-O 6 days after inducing adipocyte differentiation (a); and analyzed by real-time PCR for their expression of markers specific to: adipocytes (PPARγ, aP2) (b, left); skeletal muscle (myod, myg) (b, right); BAT (elovl3, CIDEA) (c); and thermogenesis (UCP1, PGC-1α) (d). (e–g) ctl and PRDM16-expressing primary myoblasts were stained with Oil-Red-O 7 days after inducing adipocyte differentiation (e). Real-time PCR analysis of genes expressed selectively in adipocytes (PPARγ, aP2, adiponectin) (left); BAT (elovl3, CIDEA) and during thermogenesis (PGC-1α, UCP1). (g) Western blot analysis before (day 0) and after 7 days of differentiation. (n=4; error bars are ± SD; **p<0.05).
Fig. 4
Fig. 4. PRDM16 binds and activates the transcriptional function of PPARγ
(a) Components in the PRDM16 complex from fat cells were separated by SDS-PAGE and visualized by silver staining. (b) Immunoprecipitation of PRDM16 from COS-7 cells expressing exogenous PRDM16 and/or Flag-PPARγ2 followed by western blot analysis to detect PPARγ2. (c) GST alone or a GST fusion protein containing PPARγ2 was incubated with 35S-labeled PRDM16 or SRC-1 protein (+/− 1 μM rosiglitazone). (d) GST fusion proteins containing different regions of PRDM16 were incubated with 35S-labeled PPARγ2. (e) Transcriptional activity of a PPAR-driven reporter gene in response to PPARγ/RXRα and PRDM16 or vector expression in COS-7 cells (+/− 1 μM rosiglitazone) (n=3; error bars are ± SD; **p<0.05).
Fig. 5
Fig. 5. Altered morphology and dysregulated gene expression in PRDM16-deficient brown fat
(a)Real-time PCR analysis of PRDM16 mRNA levels in putative BAT depots from E17 wildtype (Wt), heterozygous (het) and PRDM16 knock-out (KO) mice. (b) Hematoxylin and Eosin (H&E) staining of representative sections of BAT from Wt and KO mice. (c–e) Wt, het and KO BAT were examined by real-time PCR for their expression of: general adipocyte markers (aP2 and adiponectin) (c); BAT-selective genes (d); and skeletal muscle-specific genes (e). (n= 7–11 mice per group; error bars represent ± SEM). (*p < 0.05; **p < 0.01).

Comment in

Similar articles

See all similar articles

Cited by 804 articles

See all "Cited by" articles

Publication types

MeSH terms

Feedback