Annotating the secretome of mature primary human muscle cells

The Skeletal muscle is a metabolic active tissue that secretes various proteins. These so called myokines act auto-, para- and endocrine affecting muscle physiology and exert systemic effects on other tissues and organs. Myokines are also described to play a crucial role in the pathophysiology of metabolic diseases. Combining three different mass spectrometry based non-targeted and one antibody based targeted approach we investigated the secretome of differentiated primary human skeletal muscle cells derived from adult donors. A total of 548 non-redundant proteins were detected by combined proteomic profiling. Expression was confirmed on mRNA level for 501. Stringent consecutive filtering recruiting several database, i.e. SignalP, SecretomeP and ER_retention signals, the computational analysis assigned 306 as secretory proteins including 33 potentially novel myokines. This comprehensive profiling study of the human skeletal muscle secretome expands our knowledge of the composition of the human myokinome and further highlights the pivotal role of myokines in the regulation of multiple biological processes. We performed gene expression microarray analysis of primary human myotubes derived from twelve healthy individuals