Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2007 Mar 13;104(11):4401-6.
doi: 10.1073/pnas.0610615104. Epub 2007 Mar 5.

Myogenic gene expression signature establishes that brown and white adipocytes originate from distinct cell lineages

James A Timmons  1 , Kristian Wennmalm, Ola Larsson, Tomas B Walden, Timo Lassmann, Natasa Petrovic, D Lee Hamilton, Ruth E Gimeno, Claes Wahlestedt, Keith Baar, Jan Nedergaard, Barbara Cannon
Affiliations

Myogenic gene expression signature establishes that brown and white adipocytes originate from distinct cell lineages

James A Timmons et al. Proc Natl Acad Sci U S A. .

Abstract

Attainment of a brown adipocyte cell phenotype in white adipocytes, with their abundant mitochondria and increased energy expenditure potential, is a legitimate strategy for combating obesity. The unique transcriptional regulators of the primary brown adipocyte phenotype are unknown, limiting our ability to promote brown adipogenesis over white. In the present work, we used microarray analysis strategies to study primary preadipocytes, and we made the striking discovery that brown preadipocytes demonstrate a myogenic transcriptional signature, whereas both brown and white primary preadipocytes demonstrate signatures distinct from those found in immortalized adipogenic models. We found a plausible SIRT1-related transcriptional signature during brown adipocyte differentiation that may contribute to silencing the myogenic signature. In contrast to brown preadipocytes or skeletal muscle cells, white preadipocytes express Tcf21, a transcription factor that has been shown to suppress myogenesis and nuclear receptor activity. In addition, we identified a number of developmental genes that are differentially expressed between brown and white preadipocytes and that have recently been implicated in human obesity. The interlinkage between the myocyte and the brown preadipocyte confirms the distinct origin for brown versus white adipose tissue and also represents a plausible explanation as to why brown adipocytes ultimately specialize in lipid catabolism rather than storage, much like oxidative skeletal muscle tissue.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Phenotypic and myogenic factors in brown and white primary preadipocytes. Cell cultures were generated, harvested at the time points indicated, and examined for expression of genes by using RT-qPCR (n = 3 per cell type and time point) or by immunohistochemistry. (A) Myogenin, MyoD, Myf5, and Myf6 mRNA expression was determined by using RT-qPCR. Data (mean ± SE) are expressed as a percentage of the positive control value (hindlimb muscle obtained from 4-week-old mice). (B) A Northern blot was carried out to demonstrate the ucp1 expression status in primary white and brown preadipocytes at the time intervals shown. Norepinephrine (0.1 μM for 4 h) was used to induce ucp1 expression to demonstrate that the brown preadipocytes were committed to the brown cell lineage and distinct from the white preadipocytes. (C) Given the striking findings from the array analysis we aimed to rule out the possibility of any contamination from skeletal muscle cells within the brown preadipocyte culture. Immunohistochemistry was carried out to detect MyoD expression in day 2 preadipocytes (day 2 cultures have enough cells to ensure that a reasonable image can be obtained). Primary mouse myoblasts (Left) demonstrated nuclear staining (red) for MyoD, whereas at the most both brown and white preadipocytes demonstrated diffuse cytosolic staining resulting from the secondary antibody (see SI Fig. 4). At no time did we find any evidence that a distinct subpopulation of cells stained strongly for MyoD, and thus the brown preadipocytes cultures are not contaminated with myoblasts.
Fig. 2.
Fig. 2.
Expression of established and novel adipocyte marker genes in brown (br) and white (wt) preadipocytes. Primary cultures were produced, and cells were harvested at the time points indicated. (A) RT-qPCR validation of Pparg and Igf1 expression patterns in white (pre-wt) and brown (pre-br) preadipocytes (n = 3 independent cultures per cell type). In addition, verification of the microarray data for novel markers for brown (Meox2) and white (Tcf21) preadipocytes was carried out. (B) Affymetrix hybridization data for literature (Left) and novel (Right) markers of brown and white preadipocytes. Data from C2C12 (see SI Methods) are provided as a reference and further illustrate the difference in profile among brown, white, and muscle cells. The analysis is illustrative of genes that are expressed differentially across these cell types. Values are normalized to the cell type with the greatest signal; values much <20% are indicative of an “absent” call within the MAS5.0 algorithm. Of the “literature” genes, only Igfbp3 displays a qualitative difference in expression pattern; among the novel genes, Lhx8 (and Zic1) are characteristic of brown adipocytes, and Tcf21, Sphk1, Hoxa7, and DPT are characteristic of white adipocytes.
Fig. 3.
Fig. 3.
GO analysis of differentiating brown and white primary preadipocytes compared with C2C12 myoblasts and PCA. (A) Diagrammatic representation of the GO analysis carried out by using EASE. GO subgroups were collapsed into related groups to facilitate visualization of the data. For the complete breakdown of significantly enriched gene ontology groups, see SI Data Set 3. All GO groups demonstrated enhanced statistical representation (based on an EASE score and a Bonferroni-adjusted value of P < 0.05). (B) We used a PCA-based approach to compare the C2C12 differentiation data set, the SIRT1 differentiation data set (where SIRT1 overexpression prevents myoblast differentiation) with the differentiating pre-brown adipocytes and pre-white adipocytes. The data set includes day 4 undifferentiated brown (b) and white (w) preadipocytes and day 7/8 differentiating brown (B) and white (W) preadipocytes. C2C12 myoblasts are shown as m, and progressively differentiating myoblasts are plotted as M and T (http://pepr.cnmcresearch.org/). Sirt1-overexpressing cells (16) (s for 12-h differentiation and time control c, whereas S is 36-h differentiation with SIRT1 viral overexpression and time control C). After global normalization, we examined the top 100 genes that contributed to components 3 to 5 and used GO analysis to identify the putative SIRT1-regulated genes (see Methods). Components 3 and 4 are plotted. The arrows are used to illustrate the general direction of cell differentiation. It should be noted that SIRT1 (s and S) overexpression opposes the differentiation process.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Wilson-Fritch L, Nicoloro S, Chouinard M, Lazar MA, Chui PC, Leszyk J, Straubhaar J, Czech MP, Corvera S. J Clin Invest. 2004;114:1281–1289. - PMC - PubMed
    1. Sparks LM, Xie H, Koza RA, Mynatt R, Hulver MW, Bray GA, Smith SR. Diabetes. 2005;54:1926–1933. - PubMed
    1. Petersen KF, Dufour S, Befroy D, Garcia R, Shulman GI. N Engl J Med. 2004;350:664–671. - PMC - PubMed
    1. Timmons JA, Norrbom J, Scheele C, Thonberg H, Wahlestedt C, Tesch P. Genomics. 2006;87:165–172. - PubMed
    1. Cannon B, Nedergaard J. Physiol Rev. 2004;84:277–359. - PubMed

Publication types

Associated data

LinkOut - more resources

-