Impaired expression of Notch signaling genes in aged human skeletal muscle.

Notch signaling is essential for myogenesis and the regenerative potential of skeletal muscle; however, its regulation in human muscle is yet to be fully characterized. Increased expression of Notch3, Jagged1, Hes1, and Hes6 gene transcripts were observed during differentiation of cultured human skeletal muscle cells. Furthermore, significantly lower expressions of Notch1, Jagged1, Numb, and Delta-like 1 were evident in muscle biopsies from older men (60-75 years old) compared to muscle from younger men (18-25 years old).