Enhancing schistosomiasis drug discovery approaches with optimized proteasome substrates

Area of Science:

• Parasitology
• Drug Discovery
• Biochemistry

Background:

• Schistosomiasis affects over 200 million people globally, with limited therapeutic options.
• The 20S proteasome is a validated drug target in parasitic infections.
• Previous studies showed antischistosomal activity of inhibitors targeting Schistosoma mansoni 20S proteasome (Sm20S).

Purpose of the Study:

• To develop optimized subunit-specific substrates for Sm20S.
• To assess the utility of these substrates for Sm20S activity detection in parasite extracts.
• To compare Sm20S substrate and inhibition profiles across medically important schistosome species.

Main Methods:

• Developed optimized Sm20S substrates using data from Multiplex Substrate Profiling by Mass Spectrometry (MSP-MS).
• Assessed substrate activity compared to human constitutive 20S proteasome (c20S) substrates.
• Detected Sm20S activity in parasite extracts after ammonium sulfate precipitation.

Main Results:

• Optimized Sm20S substrates showed 9-fold or greater improved activity compared to traditional human c20S substrates.
• Robust Sm20S enzyme activity was detected in parasite extracts, reducing the need for extensive purification.
• Substrate and inhibition profiles for the 20S proteasome were similar across three medically important schistosome species.

Conclusions:

• Optimized Sm20S substrates offer a more efficient tool for studying proteasome activity.
• The findings simplify the process of detecting and characterizing Sm20S activity.
• Sm20S-focused inhibitor development can be extrapolated to other schistosome species, saving time and resources.