gw-5074 and Parkinson-Disease

Parkinson's disease (PD) is a common neurodegenerative disorder caused by genetic and environmental factors that results in degeneration of the nigrostriatal dopaminergic pathway in the brain. We analyzed neural cells generated from induced pluripotent stem cells (iPSCs) derived from PD patients and presymptomatic individuals carrying mutations in the PINK1 (PTEN-induced putative kinase 1) and LRRK2 (leucine-rich repeat kinase 2) genes, and compared them to those of healthy control subjects. We measured several aspects of mitochondrial responses in the iPSC-derived neural cells including production of reactive oxygen species, mitochondrial respiration, proton leakage, and intraneuronal movement of mitochondria. Cellular vulnerability associated with mitochondrial dysfunction in iPSC-derived neural cells from familial PD patients and at-risk individuals could be rescued with coenzyme Q(10), rapamycin, or the LRRK2 kinase inhibitor GW5074. Analysis of mitochondrial responses in iPSC-derived neural cells from PD patients carrying different mutations provides insight into convergence of cellular disease mechanisms between different familial forms of PD and highlights the importance of oxidative stress and mitochondrial dysfunction in this neurodegenerative disease.

Topics: Humans; Indoles; Induced Pluripotent Stem Cells; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mitochondria; Neurons; Parkinson Disease; Phenols; Protein Serine-Threonine Kinases; Sirolimus; Ubiquinone

6-Hydroxydopamine (6-OHDA) is a widely used dopaminergic neurotoxin that leads to cell apoptosis in vivo and in vitro, and is a widely accepted experimental model of neurodegeneration in Parkinson's disease. However, the molecular mechanisms responsible for 6-OHDA-induced cell apoptosis are unclear. We found that the treatment of PC12 cells with 6-OHDA resulted in a significant decrease in cell viability and elevated apoptosis as detected by MTT assay, Hoechst 33258 staining, and flow cytometry. In addition, 6-OHDA induced a time-dependent phosphorylation of ERK1/2 at Thr-202/Tyr-204 and of Raf-1 at Ser-338, but a decreased level of Raf-1 phosphorylation at Ser-259. Phosphorylation of ERK1/2 at Thr-202/Tyr-204 and Raf-1 at Ser-338 were inhibited by the Raf-1 inhibitor GW5074, while the ERK1/2 pathway inhibitor U0126 decreased phosphorylation of ERK1/2. Furthermore, 6-OHDA-induced PC12 cells apoptosis was suppressed by GW5074 and U0126. Our results suggest that GW5074 and U0126 act as neuroprotants against 6-OHDA toxicity in PC12 cells by modulating Raf-1/ERK1/2 signaling systems.

Topics: Apoptosis; Bisbenzimidazole; Blotting, Western; Butadienes; Cell Survival; Enzyme Inhibitors; Flow Cytometry; Humans; Indicators and Reagents; Indoles; MAP Kinase Signaling System; Nitriles; Oxidopamine; Parkinson Disease; PC12 Cells; Phenols; Phosphorylation; Proto-Oncogene Proteins c-raf

Genetic studies have shown that mutations in several genes may be linked to Parkinson's disease including leucine-rich repeat kinase-2 (LRRK2). The most common of the LRRK2 mutants is the Gly2019Ser mutant.. A paper suggesting that inhibitors of Gly2019Ser mutant may be useful in the treatment of Parkinson's disease associated with this mutant is evaluated.. Overexpression of the wild-type LRRK2 or the Gly2019Ser LRRK2 mutant type produced cortical neuron injury in cell culture, and the mutant also caused cell death; this was reduced by GW5074. Administered intraperitoneally to mice, GW5074 prevented the loss of neurons induced by the Gly2019Ser LRRK2 mutant.. Selective Gly2019Ser LRRK2 mutant inhibitors may have potential in the treatment of Parkinsonism associated with mutations of this gene and GW5074 is a lead compound for this.

Topics: Animals; Antiparkinson Agents; Cell Culture Techniques; Cell Death; Corpus Striatum; Genetic Vectors; Indoles; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mutation; Nerve Degeneration; Oximes; Parkinson Disease; Phenols; Phosphorylation; Protein Serine-Threonine Kinases; Rats; Simplexvirus; Tyrosine 3-Monooxygenase

Mutations in leucine-rich repeat kinase 2 (LRRK2) have been identified as a genetic cause of familial Parkinson's disease (PD) and have also been found in the more common sporadic form of PD, thus positioning LRRK2 as important in the pathogenesis of PD. Biochemical studies of the disease-causing mutants of LRRK2 implicates an enhancement of kinase activity as the basis of neuronal toxicity and thus possibly the pathogenesis of PD due to LRRK2 mutations. Previously, a chemical library screen identified inhibitors of LRRK2 kinase activity. Here, two of these inhibitors, GW5074 and sorafenib, are shown to protect against G2019S LRRK2-induced neurodegeneration in vivo in Caenorhabditis elegans and in Drosophila. These findings indicate that increased kinase activity of LRRK2 is neurotoxic and that inhibition of LRRK2 activity can have a disease-modifying effect. This suggests that inhibition of LRRK2 holds promise as a treatment for PD.

Topics: Animals; Animals, Genetically Modified; Benzenesulfonates; Caenorhabditis elegans; Cell Survival; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Enzyme Activation; Humans; Indoles; Motor Activity; Mutation; Niacinamide; Oxidopamine; Parkinson Disease; Phenols; Phenotype; Phenylurea Compounds; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Pyridines; Sorafenib; Synucleins