ABSTRACT
Small molecule modulators of mitochondrial function have been attracted much attention in recent years due to their potential therapeutic applications for neurodegenerative diseases. The mitochondrial translocator protein (TSPO) is a promising target for such compounds, given its involvement in the formation of the mitochondrial permeability transition pore in response to mitochondrial stress. In this study, we performed a ligand-based pharmacophore design and virtual screening, and identified a potent hit compound, 7 (VH34) as a TSPO ligand. After validating its biological activity against amyloid-ß (Aß) induced mitochondrial dysfunction and in acute and transgenic Alzheimer's disease (AD) model mice, we developed a library of analogs, and we found two most active compounds, 31 and 44, which restored the mitochondrial membrane potential, ATP production, and cell viability under Aß-induced mitochondrial toxicity. These compounds recovered learning and memory function in acute AD model mice with improved pharmacokinetic properties.
Subject(s)
Alzheimer Disease/drug therapy , Mitochondria/drug effects , Neuroprotective Agents/pharmacology , Protein Aggregation, Pathological/drug therapy , Small Molecule Libraries/pharmacology , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/metabolism , Animals , Cell Survival/drug effects , Cells, Cultured , Disease Models, Animal , Drug Evaluation, Preclinical , Humans , Ligands , Mice , Mitochondria/metabolism , Molecular Structure , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , Protein Aggregation, Pathological/metabolism , Protein Aggregation, Pathological/pathology , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Transcriptional Regulator ERG/antagonists & inhibitors , Transcriptional Regulator ERG/metabolismABSTRACT
We have investigated the effectiveness of transplantation of human neural stem cells into adult rat striatum prior to induction of striatal damage with the mitochondrial toxin 3-nitropropionic acid (3-NP). Systemic 3-NP administration caused widespread neuropathological deficits similar to ones found in Huntington disease (HD) including impairment in motor function (rotarod balance test) and extensive degeneration of neuron-specific nuclear antigen (NeuN)(+) neurons, calbindin(+) neurons and glutamic acid decarboxylase (GAD)(+) striatal neurons. Animals receiving intrastriatal implantation of human neural stem cells (hNSCs) 1 week before 3-NP treatments exhibited significantly improved motor performance and reduced damage to striatal neurons compared with control sham injections. In contrast, transplantation of hNSCs at 12 h after the initial 3-NP administration did not lead to any improvement in motor performance or protect striatal neurons from the 3-NP-induced toxicity. These results indicate that the presence of grafted hNSCs before 3-NP treatment is required for host striatal neuronal protection and enhanced motor function. Immunoreactivity of brain-derived neurotrophic factor (BDNF) was found in vitro in cultured hNSCs and in vivo in grafted NSCs with expression and secretion of BDNF demonstrated by RT-PCR, immunocytochemistry, dot-blot, and ELISA analyses. Thus, protective effects of proactive transplantation of hNSCs may be due, in part, to effects mediated by BDNF. The findings in this work have particular relevance to a rat model of HD in that proactive transplanted hNSCs protect host striatal neurons against neuronal injury and improve motor impairment induced by 3-NP toxicity.