Meclofenoxate Inhibits Aggregation of Alpha-synuclein in vitro
Adhuna Parui1, Soumojit Biswas1, Ipsita Roy1
1Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab, 160062, India.
Background:
α-Synuclein, a natively disordered protein, is a key component of Lewy bodies, the ubiquitinated protein aggregates which are the pathological hallmark of Parkinson's disease (PD). Meclofenoxate (centrophenoxine) is a nootropic drug which has shown beneficial therapeutic effects in various neuronal diseases. Administration of meclofenoxate enhanced levels of dopamine and improved motor function in animal models of Parkinson's disease (PD). Evidence suggested that dopamine interacts with and modulates α-synuclein aggregation.
Objective:
The aim of this work was to investigate whether the observed positive effect of addition of meclofenoxate, a nootropic agent, on dopamine level, could be correlated with its effect on aggregation of α-synuclein.
Methods:
Purification of recombinant human α-synuclein was performed by anion exchange chromatography. The purified protein was incubated in the absence and presence of meclofenoxate and was analyzed for aggregation by Thioflavin T fluorescence spectroscopy. Conformational changes in α-synuclein were monitored by fluorescence spectroscopy and fluorescence quenching studies using a neutral quencher. Secondary structure analysis of α-synuclein was monitored by circular dichroism spectroscopy.
Results:
Recombinant human α-synuclein was expressed and purified by anion-exchange chromatography. Incubation of α-synuclein with meclofenoxate led to lowering aggregation in a concentration-dependent manner. Reduction in formation of oligomers was seen which suggested the formation of an off-pathway species which did not give rise to an aggregation-competent entity. Fluorescence quenching studies revealed that the additive distorted the native conformation of α- synuclein, leading to the formation of lower amounts of aggregation-prone species.
Conclusion:
In the presence of higher concentrations of meclofenoxate, α-synuclein undergoes a change in its conformation. This change is not dependent on the concentration of the additive. This non-native conformer promotes the formation of a species which does not undergo further aggregation. Our study provides a mechanistic explanation of the earlier observation that meclofenoxate has a beneficial effect on progression of PD in animal models.
Insights
Meclofenoxate, a nootropic drug, reduces α-synuclein aggregation, a key factor in Parkinson's disease (PD). This study reveals how meclofenoxate alters α-synuclein conformation, offering a potential therapeutic mechanism for PD.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Background:
- Parkinson's disease (PD) is characterized by Lewy bodies, primarily composed of aggregated α-synuclein.
- Meclofenoxate (centrophenoxine) is a nootropic agent with demonstrated therapeutic benefits in neuronal diseases.
- Meclofenoxate administration improves motor function and dopamine levels in PD animal models, suggesting a link with α-synuclein aggregation.
Purpose of the Study:
- To investigate the correlation between meclofenoxate's positive effect on dopamine levels and its impact on α-synuclein aggregation.
- To elucidate the mechanism by which meclofenoxate influences α-synuclein aggregation.
Main Methods:
- Purification of recombinant human α-synuclein using anion-exchange chromatography.
- Assessment of α-synuclein aggregation using Thioflavin T fluorescence spectroscopy.
- Monitoring conformational changes via fluorescence spectroscopy, fluorescence quenching, and circular dichroism spectroscopy.
Main Results:
- Meclofenoxate significantly reduced α-synuclein aggregation in a concentration-dependent manner.
- The drug promoted the formation of off-pathway species, inhibiting the generation of aggregation-competent entities.
- Fluorescence quenching indicated that meclofenoxate distorts the native α-synuclein conformation, decreasing aggregation-prone species.
Conclusions:
- Meclofenoxate induces a concentration-independent conformational change in α-synuclein.
- This altered conformation leads to the formation of non-aggregating species.
- The findings provide a mechanistic basis for meclofenoxate's beneficial effects in PD models.
