E-GEOD-5042 - Transcription profiling of differentiated brown adipocytes from wild type, PGC-1 alpha knockout, or PGC-1 alpha knockout and PGC-1 beta knockdown mice to investigate the roles of PGC-1 coactivators in brown fat differentiation
Submitted on 6 September 2006, released on 27 November 2007, last updated on 27 March 2012
Mitochondria play an essential role in the ability of brown fat to generate heat, and the PGC-1 coactivators control several aspects of mitochondrial biogenesis. To investigate their specific roles in brown fat cells, we generated immortal preadipocyte lines from the brown adipose tissue of mice lacking PGC-1±. We could then efficiently knockdown PGC-1β expression by shRNA expression. Loss of PGC-1± did not alter brown fat differentiation but severely reduced the induction of thermogenic genes. Cells deficient in either PGC-1α or PGC-1β coactivators showed a small decrease in the differentiation-dependant program of mitochondrial biogenesis and respiration; however, this increase in mitochondrial number and function was totally abolished during brown fat differentiation when both PGC-1± and PGC-1 were deficient. These data show that PGC-1± is essential for brown fat thermogenesis but not brown fat differentiation, and the PGC-1 coactivators play an absolutely essential but complementary function in differentiation-induced mitochondrial biogenesis. Affymetrix microarray analysis of total RNA from wt, PGC-1± KO and PGC-1± KO; cells expressing an RNAi specific for PGC-1 knockdown was performed. Of the 461; mitochondrial genes analyzed, 181 were found to be at least 20% different between wt; and defective PGC-1± and β adipocytes (p < 0.05). More than 85% of these genes were downregulated in cells deficient for PGC-1alpha and PGC-1beta. Experiment Overall Design: Brown preadipocytes that were either WT, KO for PGC-1alpha, or KO for PGC-1alpha and deficient for PGC-1beta (knockdown through siRNA expression) were differentiated for seven days. RNA was made from biological replicates of the three different types of brown adipocytes (WT, KO expressing a control siRNA, KO expressing a siRNA specific for PGC-1beta knockdown).
transcription profiling by array, co-expression, individual genetic characteristics
Complementary action of the PGC-1 coactivators in mitochondrial biogenesis and brown fat differentiation. Marc Uldry, Wenli Yang, Julie St-Pierre, Jiandie Lin, Patrick Seale, Bruce M Spiegelman. Cell Metab 3(5):333-41 (2006)