Transcriptome and secretome analysis of mechanically stretched osteocytic cells reveals activation of signalling pathways implicated in bone regeneration and DNA-repair systems

Prescribed exercise has the potential to ameliorate tissue repair or regeneration and therefore is gaining increasing importance in regenerative rehabilitation. Osteocytes are an appealing type of bone cell to target by regenerative rehabilitation protocols due to their mechanosensitive and secretory nature. Making use of tandem liquid chromatography-mass spectrometry (LC-MSMS) as well as curated bioinformatics, we examined the secretome of mouse and human osteocytic bone cells cultured under cyclic tension delivered by a computer-controlled bioreactor. Quantitative SWATH MS analysis of the secretome secreted by mechanically stimulated cells revealed differential expression of 13 out of 759 secreted factors in mouse and 16 out of 276 in human osteocytic cells. GO enrichment analysis suggested that response to oxidative stress was the most predominant biological process in mouse and cholesterol or lipoprotein-related in human cells. Ossification and bone remodelling and manganese transport were 2 overrepresented process networks common to both mouse and human osteocytic cells