Transcriptional profile of a myotube starvation model of atrophy

• Published in: Journal of applied physiology (1985) 2005-04, Vol.98 (4), p.1396-1406
• Main Authors: Stevenson, Eric J, Koncarevic, Alan, Giresi, Paul G, Jackman, Robert W, Kandarian, Susan C
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cell culture; Cell Culture Techniques - methods; Cell Line; Disease Models, Animal; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Life Sciences (General); Medical disorders; Mice; Muscle Fibers, Skeletal - metabolism; Muscle Proteins - metabolism; Muscular Atrophy - etiology; Muscular Atrophy - metabolism; Muscular system; Space life sciences; Starvation - complications; Starvation - metabolism; Striated muscle. Tendons; Transcription Factors - metabolism; Vertebrates: osteoarticular system, musculoskeletal system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01055.2004

Department of Health Sciences, Boston University, Boston, Massachusetts Submitted 24 September 2004 ; accepted in final form 12 December 2004 Skeletal muscle wasting is a pervasive phenomenon that can result from a wide range of pathological conditions as well as from habitual muscular inactivity. The present work describes a cell-culture condition that induces significant atrophy in skeletal muscle C2C12 myotubes. The failure to replenish differentiation media in mature myotubes leads to rapid atrophy (53% in diameter), which is referred to here as starvation. Affymetrix microarrays were used to develop a transcriptional profile of control (fed) vs. atrophied (nonfed) myotubes. Myotube starvation was characterized by an upregulation of genes involved in translational inhibition, amino acid biosynthesis and transport, and cell cycle arrest/apoptosis, among others. Downregulated genes included several structural and regulatory elements of the extracellular matrix as well as several elements of Wnt/frizzled and TGF- signaling pathways. Interestingly, the characteristic transcriptional upregulation of the ubiquitin-proteasome system, calpains, and cathepsins known to occur in multiple in vivo models of atrophy were not seen during myotube starvation. With the exception of the downregulation of extracellular matrix genes, serine protease inhibitor genes, and the upregulation of the translation initiation factor PHAS-I, this model of atrophy in cell culture has a transcriptional profile quite distinct from any study published to date with atrophy in whole muscle. These data show that, although the gross morphology of atrophied muscle fibers may be similar in whole muscle vs. myotube culture, the processes by which this phenotype is achieved differ markedly. skeletal muscle; microarray; C2C12 Address for reprint requests and other correspondence: S. Kandarian, Dept. of Health Sciences, Boston Univ., 635 Commonwealth Ave., Boston, MA 02215 (E-mail: skandar{at}bu.edu )