Regulation of Muscle Hypertrophy
Our skeletal muscles make up 40-50% of our total mass and are essential for all humans to move, breath, and stand up straight. For the first 20 years of our lives and for those physically active after our muscles are continually growing. Satellite cells are responsible for this growth in our skeletal muscle and are referred to as muscle stem cells. When skeletal muscle cells are traumatized due to physical trauma or disease the regeneration process includes three general processes, destruction, regeneration and remodeling. What regulates these three processes? How are they signaled to initiate the cell cycle and what nutrients and systems do they require to carry out the processes of regeneration and growth”? Muscle regeneration is a daily occurrence for almost animals. The complex systems involved in regenerating the organ system that makes up over 40% of our bodies need to communicate properly, understanding how this is done can open doors for recreational and medical opportunities.
Main Point: Understanding the regulation of muscle hypertrophy requires an understanding of satellite cells (SC), the environment they reside in (niche) and the growth factors that stimulate and inhibit their activation. Sub Point: Satellite Cells lie in a specific niche that allows them to remain inactive until needed, residing between the sarcolemma and basal membrane of muscle cells (myofibrils). One side of the cell is attached to the basal membrane by two factors. First, the satellite cell has a layer of integrin alpha7beta1 which lies on the side where growth factors and inhibitors from the vasculature, autocrine and motor neuron systems can be received to signal an active or inactive state. Anchoring the satellite cell and its layer of integrin to the basal membrane are laminin, creating a selectively permeable membrane. On the opposite side where the satellite cell resides in a small recess on the...