A Novel Anti-inflammatory D-peptide Halts Disease Phenotype Progression in an Als Mouse Model

Background: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterised by selective neuronal death in brain stem and spinal cord. The cause is unknown, but an increasing evidence has firmly certified that neuroinflammation plays a key role in ALS pathogenesis. Neuroinflammation is a pathological hallmark of several neurodegenerative disorders and has been implicated as driver of disease progression. Here, we describe two treatment studies demonstrating the therapeutic potential of a tandem version of the well-known all-d-peptide RD2 (RD2RD2) in a transgenic mouse model of Alzheimer’s disease (APP/PS1) and in a transgenic mouse model of ALS (SOD1*G93A).Methods:APP/PS1 and SOD1*G93A mice were treated intraperitoneally for four weeks mice with RD2RD2 vs placebo. APP/PS1 brain and plasma samples were histologically and biochemically analysed for inflammatory markers, gliosis and amyloid pathology. SOD1*G93A mice were tested longitudinally during treatment in various behavioural and motor coordination tests. Brain and spinal cord samples were investigated immunohistochemically for gliosis and neurodegeneration.Results: Treatment in APP/PS1 mice revealed significant reduction in glial cell activation in the brain and significantly lower levels of inflammatory cytokines in plasma. RD2RD2 treatment in SOD1*G93A mice resulted not only in a reduction of activated astrocytes and microglia in both brain stem and lumbar spinal cord but also in a rescue of neurons in the motor cortex. Moreover, behavioural tests revealed that the disease phenotype of SOD1*G93A mice is halted during treatment.Conclusion: Based on the presented results, we conclude that RD2RD2 is a potential therapeutic candidate against ALS.