Small Molecule Mitochondria-Targeted Therapeutics for AD

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Abstract Abnormal energy homeostasis in Alzheimer’s Disease (AD) is associated with synaptic dysfunction and neurodegeneration. Emerging data generated using multiple systems biology approaches and meta-analysis in AD patients identified an AMP-protein kinase (AMPK) integrated signaling network that operates down stream of mitochondrial energy production and could provide neuroprotection in AD. We show that partial inhibition of mitochondrial complex I (MCI) improves glucose uptake and utilization, dendritic spine maturation, long-term potentiation, synaptic activity, cognitive function, and reduces Aβ and pTau accumulation, oxidative stress and inflammation resulting in neuroprotection in pre- and symptomatic preclinical mouse models of AD and aging. These studies suggest that novel strategies to alter mitochondrial energy homeostasis may have profound translational therapeutic potential for AD. Using multiple biochemistry, computational and systems biology approaches, and extensive in vivo translational studies, we developed small molecules that bind next to the flavin mononucleotide redox center of MCI mildly inhibiting its activity. The molecular mechanism of MCI inhibitors impinges on pathways induced by caloric restriction and exercise including activation of AMPK; increased resistance to oxidative stress; enhanced mitochondrial biogenesis, energetics, dynamics and function; reduction of glycogen synthase kinase 3β activity; increased levels of brain-derived neurotrophic factor (BDNF) and synaptic proteins in vivo; a reduction in levels of Aβ and pTau and inflammation ultimately blocking neurodegeneration in AD mice. We have confirmed these effects in a range of systems (primary mouse neurons, multiple mouse models of familial AD, wild-type mice fed with a high fat diet, chronologically aged mice, mitochondria isolated from mouse and human brain, human lymphocytes, fibroblasts and neuronal cells differentiated from human iPSCs), supporting the high translational potential of this approach. The advantages of our molecules include the ability to penetrate the blood brain barrier, low toxicity, in vivo efficacy, and the known molecular target. Based on the target validation and the identification of the molecular mechanism, we developed multiple in vitro and in vivo assays that were used for structure-activity relationship (SAR) studies resulting in the development of a robust Discovery Funnel and arrays of novel series of proprietary compounds MCI inhibitors with promising drug-like properties (US patent granted). We propose to advance our small molecule therapeutics to the clinic by entering the BPN at the Discovery stage where, with the team of the BPN Consultants and CROs, we will progress toward the identification of preclinical and development candidates, and to the submission of the IND application in preparation for a Phase I Clinical Trial.