Modifying Rap1-signalling by targeting Pde6δ is neuroprotective in models of Alzheimer’s disease

BACKGROUND: Neuronal Ca(2+) dyshomeostasis and hyperactivity play a central role in Alzheimer’s disease pathology and progression. Amyloid-beta together with non-genetic risk-factors of Alzheimer’s disease contributes to increased Ca(2+) influx and aberrant neuronal activity, which accelerates neurodegeneration in a feed-forward fashion. As such, identifying new targets and drugs to modulate excessive Ca(2+) signalling and neuronal hyperactivity, without overly suppressing them, has promising therapeutic potential. METHODS: Here we show, using biochemical, electrophysiological, imaging, and behavioural tools, that pharmacological modulation of Rap1 signalling by inhibiting its interaction with Pde6δ normalises disease associated Ca(2+) aberrations and neuronal activity, conferring neuroprotection in models of Alzheimer’s disease. RESULTS: The newly identified inhibitors of the Rap1-Pde6δ interaction counteract AD phenotypes, by reconfiguring Rap1 signalling underlying synaptic efficacy, Ca(2+) influx, and neuronal repolarisation, without adverse effects in-cellulo or in-vivo. Thus, modulation of Rap1 by Pde6δ accommodates key mechanisms underlying neuronal activity, and therefore represents a promising new drug target for early or late intervention in neurodegenerative disorders. CONCLUSION: Targeting the Pde6δ-Rap1 interaction has promising therapeutic potential for disorders characterised by neuronal hyperactivity, such as Alzheimer’s disease. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13024-018-0283-3) contains supplementary material, which is available to authorized users.