MYOD1 and muscle atrophy: To understand how GPRC5D-AS1 and miR-520d-5p affected atrophy cell myogenesis and differentiation, we treated human muscle atrophy model cells with empty plasmid, GPRC5D-AS1-OE plasmid, MYOD1-OE plasmid, associated miRNA control, miR-520d-5p mimic and inhibition.