Santiago Diaz sd24277
Nucleic Acid Aptamer Selection Against Myostatin as a Therapeutic Treatment for Amyotrophic Disorders
The protein myostatin, or GDF8 (growth differentiation factor 8), has been shown to regulate muscle mass growth (myogenesis) by inhibiting myoblast proliferation and differentiation. The theory is that, through a receptor-mediated signal transduction pathway, myostatin stops the cell cycle at G1 phase and prevents myoblasts from undergoing S phase. However, there are people who suffer from muscular dystrophy or other myoatrophic conditions and wish to have greater muscle mass. It is in these scenarios that myostatin inhibition might have beneficial effects.
If the myostatin molecule is somehow disabled or modified so that it can no longer activate the signal transduction pathway, then muscle growth can be promoted. One approach to this task is the use of aptamers, which are RNA or DNA oligonucleotides that are capable of binding to a specific target with high affinity and specificity. Aptamers are designed through a careful process of selection, in which the RNA ligands that bind more strongly to the desired target are replicated. Using these aptamers against myostatin might promote muscle development.
Specific aim 1: Aptamer selection against myostatin protein to inhibit myostatin action.
It is hypothesized that the myostatin aptamers will bind to its target protein before these can reach the receptors that activate the signal transduction pathway that negatively regulate proliferation and differentiation. The myostatin-aptamer conjugated protein will have such a foreign shape and form that, when it reaches the receptor, the binding site will not recognize it, rendering it incapable of triggering the signal transduction pathway, and thus, unable to inhibit muscle growth. The aptamer could also act as an allosteric inhibitor, by binding to the receptor binding site and inhibiting myostatin action.
Figure 1. Diagram of the development of myotubes(muscle cells). The black lines show at which points in the process does myostatin (MSTN) exert its negative regulation. The red lines show where the aptamers will take action to prevent myostatin from triggering the signal transduction pathway. Picture courtesy of Rios, Ramon (2001).
Myostatin can be obtained from Shenandoah Biotechnology, Inc. for $165 per 10 ug. The catalog number is 100-22.
Rios, Ramon (2001) "Myostatin is an inhibitor of myogenic differentiation" American Journal of Physiology: Cell Physiology.
Thomas, Mark (2001) "Myostatin, a Negative Regulator of Muscle Growth, Functions by Inhibiting Myoblast Proliferation" The Journal of Biological Chemistry.
Whittemore, Lisa-Anne (2003) "Inhibition of myostatin in adult mice increases skeletal muscle mass and strength" Biochemical and Biophysical Research Communications. Volume 300, Issue 4, Pages 965-971
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