Immunosuppressant FK506 does not exert beneficial effects in symptomatic G93A superoxide dismutase-1 transgenic mice

The immunosuppressant drug FK506 has been shown to exert neuroprotective effects in various model systems via inhibition of the protein phosphatase calcineurin (CN). The enzyme Cu/ Zn-superoxide dismutase (SOD1), which is mutated in a familial form of amyotrophic lateral sclerosis (ALS), is an endogenous regulator of CN. Altered function of CN may therefore be involved in the pathogenesis of ALS. We tested FK506 in a transgenic mouse model expressing mutated SOD1 for potential beneficial effects. This treatment, initiated after onset of symptoms, did not cause a reduction in the decline of motor function nor did it prolong survival. These results argue against a crucial role of CN in the process leading to motoneuronal degeneration in SOD1-mutated mice. NeuroReport 12:2663-2665 (C) 2001 Lippincott Williams & Wilkins.