Neurodegenerative diseases are a group of diseases that lead to the gradual degeneration and/or death of neurons, including Alzheimer's disease (AD) and Parkinson's disease (PD). The pathology of AD is characterized by the accumulation of extracellular amyloid beta in the form of senile plaques and the presence of intracellular neurofibrillary tangles, while PD is characterized by the degeneration of nigrostriatal dopaminergic neurons, which in turn leads to dopamine deficiency. Both diseases are associated with increased expression of monoamine oxidase (MAO), which is why the latter is an attractive target in the treatment of such neurodegenerative diseases. In recent years, proteolysis-targeting chimeras – PROTAC molecules, which utilize the body’s own ubiquitin-proteasome system to degrade target proteins, have gained importance. As part of the master’s thesis, we wanted to biologically evaluate the synthesized PROTAC molecules, which contain a ligand for the MAO A isoform, namely harmine. The compounds were evaluated using the SH-SY5Y cell line, where we first checked the expression level of the two MAO isoforms, MAO A and MAO B, as well as the expression of the E3 ligases, VHL and CRBN. In addition, the cytotoxic profile of concentrations of the compounds was determined using the spectrophotometric method and flow cytometry. To further evaluate the efficacy of the compounds, concentrations of 0.1 and 1 µM were used at which the compounds showed no effect on the viability of SH-SY5Y cells. SH-SY5Y cells were then exposed to harmine and PROTAC MAO A compounds at various time points to determine the effects on MAO A target protein degradation as detected by western blotting. Compounds KKM-39 and KMD-12 were found to be the most effective compounds for MAO A degradation, causing decreased MAO A expression in SH-SY5Y cells after 24 h of treatment. In the last part, we investigated the effect of PROTAC MAO A compounds on MAO A degradation in an in vitro cell model of neurodegeneration. For the treatment of SH-SY5Y cells we used the neurotoxin 6-hydroxydopamine, which is used to establish cell and animal models that mimic the pathology of PD. With the biological evaluation of PROTAC MAO A compounds, we aimed to determine their impact on reducing MAO A levels. However, we did not obtain the expected results due to the absence of degradation. Nevertheless, the master’s thesis indicated that some compounds are promising and with their modification, more successful compounds could be developed.
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