How does satellite cell work and regenerate the skeletal muscle fiber?

Satellite cells are able to differentiate and fuse to augment existing muscle fibers and to form new fibers. In response to mechanical strain, satellite cells become activated. Activated satellite cells initially proliferate as skeletal myoblasts before undergoing myogenic differentiation.

What are myogenic satellite cells?

Quiescent satellite cells are physically distinct from the adult myofiber as they reside in indentations between the sarcolemma and the basal lamina (130). Adult skeletal muscle fibers are terminally differentiated such that muscle growth and regeneration are accomplished by satellite cells.

How do satellite cells contribute to hypertrophy?

Adult muscle stem cells, known as satellite cells, have been shown to play an important role in muscle hypertrophic growth, during which time the satellite cells get recruited to existing muscle fibers and fuse with them to promote fiber radial growth.

How do satellite cells increase muscle?

Previous studies have shown that the number of satellite cells is increased by long-term or acute exercise training in humans and animals [4, 5] and decreases during aging in conjunction with a reduction in the muscle quality and functional potential [6].

How are PAX7 and myogenic progression in skeletal muscle?

pMSCV-Pax7-IRES-eGFP was used to infect satellite cells retained beneath the basal lamina of their associated myofibre. Wild-type myofibres were isolated and cultured in plating medium with retrovirus and then fixed between 72 and 96 hours later and immunostained.

What is the role of Pax7 in satellite cells?

Quiescent satellite cells express the transcription factor Pax7 and when activated, coexpress Pax7 with MyoD. Most then proliferate, downregulate Pax7 and differentiate.

How does PAX7 affect the differentiation of MyoD cells?

Constitutive Pax7 expression in a Pax7-null C2C12 subclone increased the proportion of cells expressing MyoD, showing that Pax7 can act genetically upstream of MyoD. However these Pax7-null cells were unable to differentiate into normal myotubes in the presence of Pax7.

Where was the paired box transcription factor PAX7 isolated?

Cell. 2000 Sep 15;102 (6):777-86. doi: 10.1016/s0092-8674 (00)00066-0. 1 Department of Biology, McMaster University, Hamilton, Ontario, Canada. The paired box transcription factor Pax7 was isolated by representational difference analysis as a gene specifically expressed in cultured satellite cell-derived myoblasts.