Animal models of Parkinson's disease 2012

The Role of the Thioredoxin System in Brain Diseases

The thioredoxin system, consisting of thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH, plays a fundamental role in the control of antioxidant defenses, cell proliferation, redox states, and apoptosis. Aberrations in the Trx system may lead to increased oxidative stress toxicity and neurodegenerative processes. This study reviews the role of the Trx system in the pathophysiology and treatment of Alzheimer's, Parkinson's and Huntington's diseases, brain stroke, and multiple sclerosis. Trx system plays an important role in the pathophysiology of those disorders via multiple interactions through oxidative stress, apoptotic, neuro-immune, and pro-survival pathways. Multiple aberrations in Trx and TrxR systems related to other redox systems and their multiple reciprocal relationships with the neurodegenerative, neuro-inflammatory, and neuro-oxidative pathways are here analyzed. Genetic and environmental factors (nutrition, metals, and toxins) may impact the function of the Trx system, thereby contributing to neuropsychiatric disease. Aberrations in the Trx and TrxR systems could be a promising drug target to prevent and treat neurodegenerative, neuro-inflammatory, neuro-oxidative stress processes, and related brain disorders.

Nesfatin-1 protects dopaminergic neurons against MPP+/MPTP-induced neurotoxicity through the C-Raf-ERK1/2-dependent anti-apoptotic pathway

Several brain-gut peptides have been reported to have a close relationship with the central dopaminergic system; one such brain-gut peptide is nesfatin-1. Nesfatin-1 is a satiety peptide that is predominantly secreted by X/A-like endocrine cells in the gastric glands, where ghrelin is also secreted. We previously reported that ghrelin exerted neuroprotective effects on nigral dopaminergic neurons, which implied a role for ghrelin in Parkinson’s disease (PD). In the present study, we aim to clarify whether nesfatin-1 has similar effects on dopaminergic neurons both in vivo and in vitro. We show that nesfatin-1 attenuates the loss of nigral dopaminergic neurons in the 1-methyl-4-phenyl-1, 2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. In addition, nesfatin-1 antagonized 1-methyl-4-phenylpyridillium ion (MPP⁺)-induced toxicity by restoring mitochondrial function, inhibiting cytochrome C release and preventing caspase-3 activation in MPP⁺-treated MES23.5 dopaminergic cells. These neuroprotective effects could be abolished by selective inhibition of C-Raf and the extracellular signal-regulated protein kinase 1/2 (ERK1/2). Our data suggest that C-Raf-ERK1/2, which is involved in an anti-apoptotic pathway, is responsible for the neuroprotective effects of nesfatin-1 in the context of MPTP-induced toxicity. These results imply that nesfatin-1 might have therapeutic potential for PD.