Can Spinal Muscular Atrophy be treated by Protease Inhibitors?

Spinal muscular atrophy is a genetic disorder characterised by weakness and wasting (atrophy) of skeletal muscles, used for movement. Loss of specialised nerve cells, called motor neurons which controls muscle movement, results in weakness of muscles. It mostly affects proximal muscles and respiratory muscles. SMA is one of the most common causes of infant death and mobility impairment.
Spinal muscular atrophy has no cure, but treatments can improve some symptoms and in some cases, help the patients live longer. Researchers are working robustly to find new ways to fight the disease. Spinraza, manufactured by Biogen is the only approved drug for the treatment of Spinal Muscular Atrophy in adults and children.

Scientists from various organisations have been trying to find out the usefulness of Protease inhibitors to cure Spinal muscular atrophy. The degeneration of Survival motor protein (SMN) due to the mutations in the SMN1 gene causes the worsening of muscles. In a recent study published in the journal Life Science Alliance, researchers have tried to demonstrate the use of Protease Inhibitors to treat SMA by increasing the levels of SMA protein. The main objective here is to target the SMN2 gene, which is a similar version of the SMN1 gene, to make more SMA protein and convert it into a more stable form. The simulations showed an inverse relationship between disease severity and the number of SMN2 gene copies. Using the CRISPR/CAS 9 gene editing tool, investigators were able to generate the cell line with a fluoresced protein attached to SMN2 gene and then screened for the fluorescent level after chemically treating the gene with different compounds.  Further, it was revealed that Z-FA-FMK, a cysteine protease inhibitor, works by inhibiting protease-mediated degradation of both SMN genes and increase the expression of functional SMA protein. 

Through the experiment, the potential therapeutic value of cysteine protease inhibitors in treating SMA via stabilising SMN proteins is visible which can help patients living with Spinal Muscular Atrophy live longer and better.