Effect of neurophilin ligands on motor units in mice with SOD1 ALS mutations.
BACKGROUND
Mice with trangenes that express mutations in the gene for cytosolic copper/zinc superoxide dismutase (SOD1) develop motor neuron degeneration resembling human ALS. Neurophilin ligands are small molecules that promote neurite outgrowth.


OBJECTIVE
To test the hypothesis that treatment with two neurophilin ligands increases survival in these ALS mice by slowing the loss of motor neurons and increasing the sizes of motor units.


METHODS
Transgenic mice hemizygous for the G93A mutation were untreated or treated from 30 days of age with one of two doses of two neurophilin ligands (V-13,670; V-10,367, Vertex Pharmaceuticals, Boston, MA). Onset of behavioral abnormalities and survival were recorded. Motor unit number estimation (MUNE) was performed every 21 days starting at age 60 days.


RESULTS
In control animals, disease onset occurred at 77.0 days of age and death occurred at 137 days of age. Neither neurophilin ligand affected the disease course. In control animals, MUNE declined with time beginning before behavioral abnormalities were noted, and motor unit size increased concomitantly. There was no effect of drug on motor unit loss as assessed by MUNE; however, motor unit size increased more rapidly and to a greater degree in animals treated with V-13,670.


CONCLUSIONS
As in human ALS, the transgenic ALS mice show physiologic changes in the motor unit prior to the development of clinical signs: MUNE declines as motor unit size increases. Although neither neurophilin ligand significantly affected survival, one produced an increase in motor unit size. The fact that survival was not altered by the increase in motor unit size may reflect the rapid disease course in this animal model.
Shefner
J M
JM
Department of Neurology, Upstate Medical University, Syracuse, NY 13210, USA. shefner@upstate.edu
Brown
R H
RH
Cole
D
D
Chaturvedi
P
P
Schoenfeld
D
D
Pastuszak
K
K
Matthews
R
R
Upton-Rice
M
M
Cudkowicz
M E
ME
D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics*; D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000235:genetics; D006801:Humans; D008222:Lymphokines / Q000187:drug effects* / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009043:Motor Activity / Q000187:drug effects; D009046:Motor Neurons / Q000187:drug effects*; D009048:Motor Skills / Q000187:drug effects; D009154:Mutation / Q000235:genetics*; D009416:Nerve Regeneration / Q000187:drug effects* / Q000235:genetics; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009930:Organic Chemicals; D011725:Pyridines / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000235:genetics*; D000072105:Superoxide Dismutase-1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D018696:Neuroprotective Agents; D009930:Organic Chemicals; D011725:Pyridines; C000606290:SOD1 protein, human; C108850:V 10367; C444011:V-13,670; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1