The effect of diet on the protective action of D156844 observed in spinal muscular atrophy mice

• Treatment of PicoLab20-fed neonatal SMN∆7 SMA mice with D156844 improves survival.
• Neonatal mice maintained on the PicoLab20 diet have elevated CNS levels of D156844.
• SMN protein levels are marginally elevated in D156844-treated, PicoLab20-fed SMN∆7 SMA mice.

Spinal muscular atrophy (SMA) is an early-onset motor neuron disease characterized by loss of spinal motor neurons which leads to skeletal muscle atrophy. Proximal SMA results from the loss or mutation of the survival motor neuron (SMN) gene. In humans, the SMN gene is duplicated to produce two nearly identical genes, SMN1 and SMN2. SMN1 is lost in SMA but SMN2 is retained; in fact, the number of SMN2 copies correlates with disease severity. The SMN2 inducer D156844 increases the survival and improves phenotype of SMN∆7 SMA mice. Maternal diet also modifies the survival and phenotype of these mice. In this study, we show the effect of maternal diet on the protective effects of D156844 in SMN∆7 SMA mice. SMA mice maintained on the PicoLab20 Mouse diet survived longer when treated with D156844; the effect of diet was additive to the effect of D156844 on these mice. Brain levels of D156844 were higher in neonatal mice maintained on the PicoLab20 diet than those on the Harlan-Teklad 22/5 diet. SMN protein levels in the spinal cord were modestly elevated in D156844-treated, PicoLab20-maintained SMA mice. These data show that maternal diet does influence the responsiveness of D156844 in neonatal SMN∆7 SMA mice.