In Vivo Regulation of Human Skeletal Muscle Gene Expression by Thyroid Hormone

Abstract

Thyroid hormones are key regulators of metabolism that modulate transcription via nuclear receptors. Hyperthyroidism is associated with increased metabolic rate, protein breakdown, and weight loss. Although the molecular actions of thyroid hormones have been studied thoroughly, their pleiotropic effects are mediated by complex changes in expression of an unknown number of target genes. Here, we measured patterns of skeletal muscle gene expression in five healthy men treated for 14 days with 75 µg of triiodothyronine, using 24,000 cDNA element microarrays. To analyze the data, we used a new statistical method that identifies significant changes in expression and estimates the false discovery rate. The 381 up-regulated genes were involved in a wide range of cellular functions including transcriptional control, mRNA maturation, protein turnover, signal transduction, cellular trafficking, and energy metabolism. Only two genes were down-regulated. Most of the genes are novel targets of thyroid hormone. Cluster analysis of triiodothyronine-regulated gene expression among 19 different human tissues or cell lines revealed sets of coregulated genes that serve similar biologic functions. These results define molecular signatures that help to understand the physiology and pathophysiology of thyroid hormone action.

Serum amyloid A: production by human white adipocyte and regulation by obesity and nutrition

“…Aliquots (15 μg) of total RNA from each of the 14 obese women (see Table 1 for clinical data) without a LEPR mutation were pooled to provide a reference for microarray experiments. The MessageAmp RNA Kit (Ambion, Austin, TX, USA) was used to amplify mRNA [20,21]. The CyScribe First-Strand cDNA Labelling Kit (Amersham Biosciences, Orsay, France) was used to label 15 μg of amplified RNA.…”

“…The cDNA microarrays consisted of PCRamplified cDNAs printed on glass slides with 42,786 spots representing 29,308 UniGene clusters. The procedure has previously been described in detail [20,21]. Briefly, after scanning the four arrays, the resulting images were analysed using Stanford Microarray Database Online resources (http://genome-www5.stanford.edu/MicroArray/SMD, accessed 8 March 2004).…”

“…Quantitation of mRNA levels Quantitative RT-PCR was performed using the GeneAmp 7000 Sequence Detection System (Applied Biosystems, Courtaboeuf, France) as previously described [20]. We used 18S rRNA as the control.…”

Microarray Profiling of Human Skeletal Muscle Reveals That Insulin Regulates ∼800 Genes during a Hyperinsulinemic Clamp

“…Genes with significant changes in mRNA levels in response to insulin were identified using the Significant Analysis of Microarrays (SAM) procedure (12), a validated statistical technique for identifying differentially expressed genes across high density microarrays. This procedure provides a list of "significant" genes and an estimate of the false discovery rate, which represents the percentage of genes that could be identified by chance (9,12).…”

“…To determine the global transcriptional modifications directly produced by insulin in human skeletal muscle, we used cDNA microarrays (9) to analyze the changes in the mRNA levels of 29,308 genes and expressed sequence tags (ESTs) 1 induced by 3 h of euglycemic hyperinsulinemic clamp in the vastus lateralis muscle of healthy lean subjects. It is well accepted that the hyperinsulinemic clamp method allows the * This work was supported in part by INSERM Action Thématique concertée Nutrition Grant 4NU10G and by grants from the Institut de Recherche Servier, Région Rhône-Alpes, and Claude Bernard Fondation.…”