Microarray on mouse soleus muscles from DMP1 Cre Mbtps1 knockout mice compared with littermate controls. Mus musculus

Interestingly, the DMP1 cre Mbtps1 knockout mice do not demonstrate a noticeable bone phenotype despite gene expression changes. Only change was in bone stiffness. However, muscles from DMP1 cre Mbtps1 knockout mice did show a phenotype: changes in contractile force (increased); changes in myosin heavy chain expression, and an increase in myocyte regeneration evidenced by centralized nuclei in type I myosin heavy chain expressing cells. As a result, we wanted to know if these physiological changes were accompanied by changes in gene expression. We found that a number of genes were increased---including those associated with improved muscle performance and with activation of satellite cells, e.g., muscle stem cells. These changes in gene expression support our hypothesis which is that the bone (osteocytes) signal a change in muscle function via a cross-talk mechanism. Overall design: Soleus muscles from three controls and three knockout mice were dissected and flash frozen in liquid nitrogen. Muscles were then extracted for total RNA and subjected to array analysis