A promising approach to neurotherapeutics involves activating the nuclear-factor-E2-related factor 2 ( Nrf2 ) / antioxidant response element signaling, which regulates expression of antioxidant, anti-inflammatory, and cytoprotective genes.
Tecfidera, a putative Nrf2 activator, is an oral formulation of Dimethylfumarate ( DMF ) used to treat multiple sclerosis. Researchers compared the effects of DMF and its bioactive metabolite Monomethylfumarate ( MMF ) on Nrf2 signaling and their ability to block 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced experimental Parkinson's disease.
In vitro DMF and MMF activate the Nrf2 pathway via S-alkylation of the Nrf2 inhibitor Keap1 and by causing nuclear exit of the Nrf2 repressor Bach1.
Nrf2 activation by DMF but not MMF was associated with depletion of glutathione, decreased cell viability, and inhibition of mitochondrial oxygen consumption and glycolysis rates in a dose-dependent manner, whereas MMF increased these activities in vitro.
However, both DMF and MMF upregulated mitochondrial biogenesis in vitro in an Nrf2-dependent manner.
Despite the in vitro differences, both DMF and MMF exerted similar neuroprotective effects and blocked MPTP neurotoxicity in wild-type but not in Nrf2 null mice.
The data suggest that DMF and MMF exhibit neuroprotective effects against MPTP neurotoxicity because of their distinct Nrf2-mediated antioxidant, anti-inflammatory, and mitochondrial functional / biogenetic effects, but MMF does so without depleting glutathione and inhibiting mitochondrial and glycolytic functions.
Given that oxidative damage, neuroinflammation, and mitochondrial dysfunction are all implicated in the pathogenesis of Parkinson’s disease, the results provide preclinical evidence for the development of MMF rather than DMF as a novel therapeutic for Parkinson’s deasese.
Almost two centuries since its first description by James Parkinson, Parkinson's disease remains an incurable disease with limited symptomatic treatment.
The current study provides preclinical evidence that a drug, Dimethylfumarate, and its metabolite Monomethylfumarate can block nigrostriatal dopaminergic neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson’s disease.
It has been elucidated mechanism by which DMF and its active metabolite MMF activates the redox-sensitive transcription factor nuclear-factor-E2-related factor 2 ( Nrf2 ) to upregulate antioxidant, anti-inflammatory, mitochondrial biosynthetic and cytoprotective genes to render neuroprotection via distinct S-alkylating properties and depletion of glutathione.
The data suggest that targeting Nrf2-mediated gene transcription using MMF rather than DMF is a promising approach to block oxidative stress, neuroinflammation, and mitochondrial dysfunction for therapeutic intervention in Parkinson’s disease while minimizing side effects. ( Xagena )
Source: Journal of Neuroscience, 2016