Ditte Caroline Andersen, Ditte Caroline3; Kristiansen, Gitte Qvist1; Jensen, Line4; Füchtbauer, Ernst-Martin7; Schrøder, Henrik Daa6; Jensen, Charlotte Harken3
1 Department of Molecular Biology, Faculty of Science, Aarhus University, Aarhus University2 Department of Molecular Biology and Genetics, Science and Technology, Aarhus University3 Department of Cancer and Inflammation Research, University of Southern Denmark4 Department of Cancer and Inflammation Research, University of Southern Denmark and Department of Clinical Pathology, Odense University Hospital5 Department of Molecular Biology and Genetics - Molecular Cell and Developmental Biology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University6 Department of Clinical Pathology, Odense University Hospital7 Department of Molecular Biology and Genetics - Molecular Cell and Developmental Biology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
The skeletal muscle-derived side population (mSP) which highly excludes Hoechst 33342 is composed of CD45(+) and CD45(-) subpopulations; yet, rareness of mSP cells in general has complicated extensive quantitative analysis of gene expression profiles in primarily isolated mSP cells. Here, we describe the isolation of adult mouse normal skeletal muscle residing SPCD45(+) and SPCD45(-) cells from a parent mononuclear muscle-derived cell (MDC) population. Relative quantitative real time PCR (RT-PCR) of 64 genes revealed that mSPCD45(-) compared with mSPCD45(+) was enriched for cells expressing transcripts associated with endothelial cells, Notch signaling and myogenic precursors. By comparing the mRNA signatures of mSPs with those of adipose tissue-derived SP populations, a common endothelial component seemed to reside in both muscle and fat-derived SPCD45(-) entities. However, each SP subset was clearly specified by the tissue from which the cells originated suggesting that muscle SPs compared with adipose tissue SPs are predisposed towards differentiation into the myogenic lineage. Thus, our data support the previously suggested hypothesis that satellite cell precursors (or alternatively a satellite cell subpopulation) remain in the mSPCD45(-) fraction, and we show that these cells express high levels of many of the known myogenic precursor/stem cell related markers, including Pax7 and Myf5.