doi:10.1369/jhc.5A6675.2006
Volume 54 (4): 375-384, 2006 Copyright ©The Histochemical Society, Inc. Sphingomyelin Levels in the Plasma Membrane Correlate with the Activation State of Muscle Satellite Cells
Department of Life Sciences, The University of Tokyo, Tokyo, Japan (YN,RM); Muscle Cell Biology Group, Medical Research Council Clinical Sciences Centre, Imperial College, London, United Kingdom (YN,PSZ); Randall Division of Cell and Molecular Biophysics, King's College London School of Biomedical and Health Sciences, Guy's Campus, London, United Kingdom (PSZ); Department of Molecular Biodynamics, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan (HK,MU); Research Laboratory, Zenyaku Kogyo Co. Ltd., Tokyo, Japan (NO,SK) Correspondence to: Dr. Ryoichi Matsuda, Department of Life Sciences, The University of Tokyo, Rm. 15-309A, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan. E-mail: cmatsuda{at}mail.ecc.u-tokyo.ac.jp Satellite cells are responsible for postnatal growth, hypertrophy, and regeneration of skeletal muscle. They are normally quiescent, and must be activated to fulfill these functions, yet little is known of how this is regulated. As a first step in determining the role of lipids in this process, we examined the dynamics of sphingomyelin in the plasma membrane. Sphingomyelin contributes to caveolae/lipid rafts, which act to concentrate signaling molecules, and is also a precursor of several bioactive lipids. Proliferating or differentiated C2C12 muscle cells did not bind lysenin, a sphingomyelin-specific binding protein, but noncycling reserve cells did. Quiescent satellite cells also bound lysenin, revealing high levels of sphingomyelin in their plasma membranes. On activation, however, the levels of sphingomyelin drop, so that lysenin did not label proliferating satellite cells. Although most satellite cell progeny differentiate, others stop cycling, maintain Pax7, downregulate MyoD, and escape immediate differentiation. Importantly, many of these Pax7-positive/MyoD-negative cells also regained lysenin binding on their surface, showing that the levels of sphingomyelin had again increased. Our observations show that quiescent satellite cells are characterized by high levels of sphingomyelin in their plasma membranes and that lysenin provides a novel marker of myogenic quiescence. (J Histochem Cytochem 54:375384, 2006)
Key Words: satellite cell stem cell skeletal muscle activation regeneration sphingolipid sphingomyelin lysenin
This article has been cited by other articles:
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||