Rho-kinase inactivation prolongs survival of an intermediate SMA mouse model.
Spinal muscular atrophy (SMA) is an inherited disease resulting in the highest mortality of children under the age of two. SMA is caused by mutations or deletions in the survival motor neuron 1 (SMN1) gene, leading to aberrant neuromuscular junction (NMJ) development and the loss of spinal cord alpha-motor neurons. Here, we show that Smn depletion leads to increased activation of RhoA, a major regulator of actin dynamics, in the spinal cord of an intermediate SMA mouse model. Treating these mice with Y-27632, which inhibits ROCK, a direct downstream effector of RhoA, dramatically improves their survival. This lifespan rescue is independent of Smn expression and is accompanied by an improvement in the maturation of the NMJs and an increase in muscle fiber size in the SMA mice. Our study presents evidence linking disruption of actin cytoskeletal dynamics to SMA pathogenesis and, for the first time, identifies RhoA effectors as viable targets for therapeutic intervention in the disease.
Bowerman
Mélissa
M
Ottawa Hospital Research Institute, Ottawa, ON, Canada K1H 8L6.
Beauvais
Ariane
A
Anderson
Carrie L
CL
Kothary
Rashmi
R
D000577:Amides / Q000008:administration & dosage; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009134:Muscular Atrophy, Spinal / Q000201:enzymology* / Q000235:genetics / Q000401:mortality*; D009469:Neuromuscular Junction / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage; D011725:Pyridines / Q000008:administration & dosage; D013116:Spinal Cord / Q000201:enzymology / Q000378:metabolism; D013534:Survival; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics* / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D000577:Amides; D047428:Protein Kinase Inhibitors; D011725:Pyridines; C526472:Smn1 protein, mouse; D055533:Survival of Motor Neuron 1 Protein; C108830:Y 27632; D020742:rhoA GTP-Binding Protein