Effect of Capsaicin on the Climbing Ability in Drosophila Model of Parkinson’s Disease

Transient Receptor Potential Channels as an Emerging Target for the Treatment of Parkinson's Disease: An Insight Into Role of Pharmacological Interventions

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the symptoms of motor deficits and cognitive decline. There are a number of therapeutics available for the treatment of PD, but most of them suffer from serious side effects such as bradykinesia, dyskinesia and on-off effect. Therefore, despite the availability of these pharmacological agents, PD patients continue to have an inferior quality of life. This has warranted a need to look for alternate strategies and molecular targets. Recent evidence suggests the Transient Receptor Potential (TRP) channels could be a potential target for the management of motor and non-motor symptoms of PD. Though still in the preclinical stages, agents targeting these channels have shown immense potential in the attenuation of behavioral deficits and signaling pathways. In addition, these channels are known to be involved in the regulation of ionic homeostasis, which is disrupted in PD. Moreover, activation or inhibition of many of the TRP channels by calcium and oxidative stress has also raised the possibility of their paramount involvement in affecting the other molecular mechanisms associated with PD pathology. However, due to the paucity of information available and lack of specificity, none of these agents have gone into clinical trials for PD treatment. Considering their interaction with oxidative stress, apoptosis and excitotoxicity, TRP channels could be considered as a potential future target for the treatment of PD.

The Drosophila Model: Exploring Novel Therapeutic Compounds against Neurodegenerative Diseases

Polyphenols are secondary metabolites of plants, fruits, and vegetables. They act as antioxidants against free radicals from UV light, pathogens, parasites, and oxidative stress. In Drosophila models, feeding with various polyphenols results in increased antioxidant capacity and prolonged lifespan. Therefore, dietary polyphenols have several health advantages for preventing many human diseases, including cardiovascular diseases, cancer, and neurodegenerative diseases. However, the exact role of polyphenols in neurodegenerative diseases is still yet to be completely defined. This review focuses on the most recent studies related to the therapeutic effect of polyphenols in neurodegenerative disease management and provides an overview of novel drug discovery from various polyphenols using the Drosophila model.

Effect of epicatechin gallate dietary supplementation on transgenic Drosophila model of Parkinson's disease

Parkinson's disease (PD) is characterized by progressive loss of dopaminergic neurons and aggregation of alpha synuclein (αS) in the brain. The role of epicatechin gallate (EG) was studied on the transgenic Drosophila model of flies expressing normal human alpha synuclein (h-αS) in the neurons. The objectives of the present work include the study of the effect of EG on the climbing ability, lipid peroxidation, and apoptosis in the brain of PD model flies. These flies exhibit locomotor dysfunction as the age progresses. EG at final concentration of 0.25, 0.50, and 1.0 μg/mL was supplemented in diet and flies were allowed to feed for 24 days. The climbing ability was assessed after 24 days. The supplementation of 0.25, 0.50, and 1.0 μg/mL of EG showed a dose-dependent significant delay in the loss of climbing ability and reduced the oxidative stress and apoptosis in the brain of PD model flies.

Effect of curcumin on lifespan, activity pattern, oxidative stress, and apoptosis in the brains of transgenic Drosophila model of Parkinson's disease

Background. A time dependent loss of dopaminergic neurons and the formation of intracellular aggregates of alpha synuclein have been reported in PD model flies. Methods. The progeny (PD flies) expressing human alpha synuclein was exposed to 25, 50, and 100 µM of curcumin mixed in the diet for 24 days. The effect of curcumin was studied on lifespan, activity pattern, oxidative stress, and apoptosis in the brains of PD model flies. The activity of PD model flies was monitored by using Drosophila activity monitors (DAMs). For the estimation of oxidative stress, lipid peroxidation and protein carbonyl content were estimated in the flies brains of each treated groups. The cell death in Drosophila brain was analyzed by isolating brains in Ringer's solution placing them in 70% ethanol and stained in acridine orange to calculate the gray scale values. Results. The exposure of flies to 25, 50, and 100 µM of curcumin showed a dose dependent significant delay in the loss of activity pattern, reduction in the oxidative stress and apoptosis, and increase in the life span of PD model flies. Conclusion. Curcumin is potent in reducing PD symptoms.

Synthesis of alginate-curcumin nanocomposite and its protective role in transgenic Drosophila model of Parkinson's disease

The genetic models in Drosophila provide a platform to understand the mechanism associated with degenerative diseases. The model for Parkinson's disease (PD) based on normal human alpha-synuclein (αS) expression was used in the present study. The aggregation of αS in brain leads to the formation of Lewy bodies and selective loss of dopaminergic neurons due to oxidative stress. Polyphenols generally have the reduced oral bioavailability, increased metabolic turnover, and lower permeability through the blood brain barrier. In the present study, the effect of synthesized alginate-curcumin nanocomposite was studied on the climbing ability of the PD model flies, lipid peroxidation, and apoptosis in the brain of PD model flies. The alginate-curcumin nanocomposite at final doses of 10⁻⁵, 10⁻³, and 10⁻¹ g/mL was supplemented with diet, and the flies were allowed to feed for 24 days. A significant dose-dependent delay in the loss of climbing ability and reduction in the oxidative stress and apoptosis in the brain of PD model flies were observed. The results suggest that alginate-curcumin nanocomposite is potent in delaying the climbing disability of PD model flies and also reduced the oxidative stress as well as apoptosis in the brain of PD model flies.

Effect of L-ascorbic Acid on the climbing ability and protein levels in the brain of Drosophila model of Parkinson's disease

In the present study, the effect of l-ascorbic acid (AA) was studied on the climbing ability of the Parkinson's disease (PD) model Drosophila expressing normal human alpha synuclein (h-αs) in the neurons. These flies show locomotor dysfunction as the age progresses. AA at final concentration of 11.35 × 10(-5) M, 22.71 × 10(-5) M, 45.42 × 10(-5) M, and 68.13 × 10(-5) M was added to the diet, and the flies were allowed to feed for 21 days. AA at 11.35 × 10(-5) M did not show any significant delay in the loss of climbing ability of PD model flies. However, AA at 22.71 × 10(-5) M, 45.42 × 10(-5) M, and 68.13 × 10(-5) M showed a dose dependent significant (p < .05) delay in the loss of climbing ability of PD model flies as compared to the untreated PD flies. The total protein concentration in brain homogenate was measured in treated as well as control groups after 21 days, no significant difference was obtained between treated as well as control (PD flies and l-dopa) groups. The results suggest that AA is potent in delaying the climbing disability of the PD model flies expressing h-αs in the neurons.