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Radiological biomarkers have been reported for multiple system atrophy and progressive supranuclear palsy, but serum/plasma biomarkers for each disorder have not been established. In this context, we performed a pilot study to identify disease-specific plasma biomarkers for multiple system atrophy and progressive supranuclear palsy. Plasma samples collected from 20 progressive supranuclear palsy patients, 16 multiple system atrophy patients and 20 controls were investigated by comprehensive metabolome analysis using capillary electrophoresis mass spectrometry and liquid chromatography mass spectrometry. Medication data were obtained from patients with multiple system atrophy and progressive supranuclear palsy, and correlations with associated metabolites were examined. Receiver operating characteristics curve analyses were used to investigate diagnostic values for each disorder. The levels of 15 and eight metabolites were significantly changed in multiple system atrophy and progressive supranuclear palsy, respectively. Multiple system atrophy was mainly characterized by elevation of long-chain fatty acids and neurosteroids, whereas progressive supranuclear palsy was characterized by changes in the level of oxidative stress-associated metabolites. Receiver operating characteristic curve analyses revealed that patients with multiple system atrophy or progressive supranuclear palsy were effectively differentiated from controls by 15 or 7 metabolites, respectively. Disease-specific metabolic changes of multiple system atrophy and progressive supranuclear palsy were identified. These biomarker sets should be replicated in a larger sample.

In the course of screening for the anti-Parkinsonian drugs from a library of traditional herbal medicines, we found that the extracts of choi-joki-to and daio-kanzo-to protected cells from MPP+-induced cell death. Because choi-joki-to and daio-kanzo-to commonly contain the genus Glycyrrhiza, we isolated licopyranocoumarin (LPC) and glycyrurol (GCR) as potent neuroprotective principals from Glycyrrhiza. LPC and GCR markedly blocked MPP+-induced neuronal PC12D cell death and disappearance of mitochondrial membrane potential, which were mediated by JNK. LPC and GCR inhibited MPP+-induced JNK activation through the suppression of reactive oxygen species (ROS) generation, thereby inhibiting MPP+-induced neuronal PC12D cell death. These results indicated that LPC and GCR derived from choi-joki-to and daio-kanzo-to would be promising drug leads for PD treatment in the future.

Mutations in p150glued cause hereditary motor neuropathy with vocal cord paralysis (HMN7B) and Perry syndrome (PS). Here we show that both overexpression of p150glued mutants and knockdown of endogenous p150glued induce apoptosis. Overexpression of a p150glued plasmid containing either a HMN7B or PS mutation resulted in cytoplasmic p150glued-positive aggregates and was associated with cell death. Cells containing mutant p150glued aggregates underwent apoptosis that was characterized by an increase in cleaved caspase-3- or Annexin V-positive cells and was attenuated by both zVAD-fmk (a pan-caspase inhibitor) application and caspase-3 siRNA knockdown. In addition, overexpression of mutant p150glued decreased mitochondrial membrane potentials and increased levels of translocase of the mitochondrial outer membrane (Tom20) protein, indicating accumulation of damaged mitochondria. Importantly, siRNA knockdown of endogenous p150glued independently induced apoptosis via caspase-8 activation and was not associated with mitochondrial morphological changes. Simultaneous knockdown of endogenous p150glued and overexpression of mutant p150glued had additive apoptosis induction effects. These findings suggest that both p150glued gain-of-toxic-function and loss-of-physiological-function can cause apoptosis and may underlie the pathogenesis of p150glued-associated disorders.