Latrepirdine stimulates autophagy and reduces accumulation of α-synuclein in cells and in mouse brain

Latrepirdine (Dimebon; dimebolin) is a neuroactive compound that was associated with enhanced cognition, neuroprotection, and neurogenesis in laboratory animals, and has entered phase II clinical trials for both Alzheimer’s (AD) and Huntington’s diseases (HD). Based on recent indications that latrepirdine protects cells against cytotoxicity associated with expression of aggregatable neurodegeneration-related proteins, including Aβ42 and γ-synuclein, we sought to determine whether latrepirdine offers protection to Saccharomyces cerevisiae (S. cerevisiae). We utilized separate and parallel expression in yeast of several neurodegeneration-related proteins, including α-synuclein, the amyotrophic lateral sclerosis-associated genes TDP43 and FUS, and the HD-associated protein huntingtin with a 103 copy-polyglutamine expansion (HTT gene; htt-103Q). Latrepirdine effects on α-synuclein clearance and toxicity were also measured following treatment of SH-SY5Y cells or chronic treatment of wildtype mice. Latrepirdine only protected yeast against the cytotoxicity associated with α-synuclein, and this appeared to occur via induction of autophagy. We further report that latrepirdine stimulated the degradation of α-synuclein in differentiated SH-SY5Y neurons, and in mouse brain following chronic administration, in parallel with elevation of the levels of markers autophagic activity. Ongoing experiments will determine the utility of latrepirdine to abrogate α-synuclein accumulation in transgenic mouse models of α-synuclein neuropathology. We propose that latrepirdine may represent a novel scaffold for discovery of robust pro-autophagic/anti-neurodegeneration compounds, that might yield clinical benefit for synucleinopathies including PD, Lewy body dementia, REM sleep disorder, and/or multiple system atrophy, following optimization of its pro-autophagic and pro-neurogenic activities.