HEY1 and Miyoshi myopathy: After 14 days, MM cells significantly reduced P1NP and increased CTX levels in the culture media, downregulated the expression of the osteoblast marker BGLAP, and upregulated the expression of the pro-osteoclastogenic cytokine RANKL and the Notch target genes HES1 and HEY1 (Fig. 4C-E).