Proteomic analysis of substantia nigra reveals molecular insights into
the neuroprotection effect of rosmarinic acid treatment in MPTP-induced
mouse model of Parkinson's Disease.
Abstract
Parkinson’s disease (PD) is neuropathologically characterized by the
progressive degeneration of dopaminergic (DA) neurons in the substantia
nigra pars compacta (SNpc), affecting 10 million people worldwide.
Rosmarinic acid (RA), a polyphenol found in plants like rosemary
(Rosmarinus officinalis), is known for its intriguing biological
properties and potential antioxidant and neuroprotective effects. In a
previous study we showed that RA treatment prevented hyperlocomotion in
mice with MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced
parkinsonism and improved the monoaminergic system in healthy animals.
However, the molecular mechanisms underlying RA’s action in PD remain
unclear. In this study, we treated MPTP-induced PD animals (C57BL/6 male
mice) with RA orally at a dose of 100 mg/kg for 15 days and examined the
proteome of substantia nigra (SN) to identify possible regulatory
targets of RA treatment to shed some lights into its neuroprotective
effects. Quantitative proteomics revealed that RA treatment regulated
proteins associated with oxidative phosphorylation (OXPHOS),
glutamatergic synapse, and vesicular cycle signaling pathway. We
identified 371 proteins significantly regulated in response to RA
administration (255 upregulated and 116 downregulated). Notably, some
cellular targets of RA treatment reported here, including
mGluR2/mGluR3/EAAT - proteins from the glutamatergic system - and
proteins from the Complex I of the electron transport chain are
promising targets for therapeutic intervention. These findings highlight
the molecular differences between MPTP-induced PD mice and those treated
with RA, providing insights on the molecular basis behind the
neuroprotective effects of RA and revealing potential PD signatures that
warrant further investigation.