The role of Pax7 in muscle satellite cells activation and myoblasts proliferation

Abstract

Muscle stem cells (MuSCs), also known as muscle satellite cells, are a type of adult stem cell located in the skeletal muscle tissue between the plasma membrane of myofibers and the surrounding basal lamina. Upon injury, quiescent MuSCs undergo activation, proliferation, self-renewal, and differentiation. Deficiencies in MuSCs can cause severe symptoms, such as muscle weakness and atrophy. The transcription factor Pax7 belongs to the paired box transcription factor family and is known to be specifically expressed in quiescent MuSCs in adult skeletal muscle. Pax7 plays an essential role in MuSC quiescence maintenance, activation, proliferation, and self-renewal. Pax7^-/- MuSCs exhibit an obvious delay from G0 to S phase re-entry during MuSCs activation. This delay is found to be controlled by Pax7 through pGSK3α-CyclinD1-pRb axis. CyclinD1 level is significantly decreased in Pax7^-/- MuSCs and myoblasts. Pax7^-/- myoblasts have a delay in the S phase of cell proliferation. Additionally, Pax7 has a dual effect on MyoD expression, it can maintain MyoD in myoblast proliferation but accelerate its downregulation in myoblast self-renewal. The study of the role of Pax7 in MuSCs’ activation, proliferation, and self-renewal can help us better understand the progress of muscle regeneration under both physiological and pathological conditions.

Date of Award	2024
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Zhenguo WU (Supervisor)