African walnut (Tetracarpidium conophorum) extract upregulates glucocerebrosidase activity and circumvents Parkinsonian changes in the Hippocampus via the activation of heatshock proteins

Abstract

BackgroundNeurodegenerative illnesses like Parkinson's and Alzheimer's are largely caused by the accumulation of aggregated proteins. Heat shock proteins (HSPs), which are molecular chaperons, have been linked with the modulation of β-glucocerebrosidase (GCase) function encoded by GBA1 and Synucleinopathies. Herein, the chaperonic properties of African walnut ethanolic extract (WNE) in manganese-induced Parkinsonian neuropathology in the hippocampus was examined. Methodology48 adult male rats weighing 185 g ± 10 g were randomly assigned into 6 (A – F) groups (n = 8) and treated orally as follows: A-PBS (1 ml daily for 28 days), B-WNE (200 mg/kg daily for 28 days), C- WNE (400 mg/kg daily for 28 days), D-Mn (100 mg/kg daily for 28 days), E-Mn plus WNE (100 mg/kg Mn + 200 mg/kg WNE daily concomitantly for 28 days), F-Mn plus WNE (100 mg/kg Mn + 400 mg/kg WNE daily concomitantly for 28 days). ResultsRats treated with WNE showed increased levels of HSP70 and HSP90 in comparison with the Mn-intoxicated group. GCase activity also increased significantly in animals treated with WNE. Our results further revealed the therapeutic tendencies of WNE against Mn toxicity by modulating oligomeric α-synuclein levels, redox activity, and glucose bioenergetics. Furthermore, immunohistochemical evaluation revealed reduced expression of neurofibrillary tangles, and reactive astrogliosis following WNE treatment. ConclusionThe ethanolic extract of African Walnut induced the activation of HSPs and increased the expression of GBA1 gene in the hippocampus. Activated heat shock proteins suppressed neurodegenerative changes due to Manganese toxicity. WNE was also shown to modulate neuroinflammatory, bioenergetics and neural redox balance in Parkinson-like neuropathology. This study was limited to the use of crude walnut extract and the evaluation of non-motor cascades of Parkinson’s disease.