Design and synthesis of proteolytically stable and cell permeable activators of human 20S proteasome and assessing their influence on the enzyme activity in cellular models of neurodegenerative diseases

We had identified a new class of peptide-based proteasome activators, inspired by the C-terminal fragment of the Blm10 protein – the yeast equivalent of PA200. An activator called Blm-pep and its analogs strongly stimulated the proteasome. However, they were degraded rapidly in the body and were unable to enter cells. We worked on improving these properties.We designed peptidomimetics which showed resistance to proteases present in human plasma. The compounds interacted with the human proteasome and possessed the ability to activate it. Their activity was enhanced in comparison to the parent peptides, with the most effective modulators boosting proteasome function up to 10-fold.We also tested our compounds on proteins directly linked to neurodegenerative diseases: tau (Alzheimer’s disease) and α-synuclein (Parkinson’s disease). The activators accelerated their degradation by the proteasome. By attaching so-called cell-penetrating peptides, we enabled the activators to cross cell membranes and even the blood–brain barrier – a crucial feature for potential therapeutic use.Further experiments confirmed that the compounds were not cytotoxic and worked not only in test tubes but also inside cells. In a model of mouse neurons mimicking Parkinson’s disease, we demonstrated that our activators effectively promoted the removal of toxic α-synuclein without reducing neuronal survival.Please consult the Readme.txt file for additional information.