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Published on: May 25, 2018
Systematic identification of substrates for profiling of secreted proteases from Aspergillus species
René Schaal1, Claudio Kupfahl, Dieter Buchheidt
1Institute for Clinical Chemistry, Medical Faculty Mannheim of the University of Heidelberg, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany.
Abstract:
Reliable and early diagnosis of life-threatening invasive mycoses in neutropenic patients caused by fungi of the Aspergillus species remains challenging because current clinical diagnostic tools lack in sensitivity and/or specificity. During invasive growth a variety of fungal proteases are secreted into the bloodstream and protease profiling with reporter peptides might improve diagnosis of invasive aspergillosis in serum specimens. To characterise the specific protease activity of Aspergillus fumigatus and Aspergillus niger we analyzed Aspergillus culture supernatants, human serum and the mixture of both. A systematic screening for optimised protease substrates was performed using a random peptide library consisting of 360 synthetic peptides featuring fluorescence resonance energy transfer (FRET). We could identify numerous peptides that are selectively cleaved by fungus-specific proteases. These reporter peptides might be feasible for future protease profiling of serum specimens to improve diagnosis and monitoring of invasive aspergillosis.
Insights
Diagnosing invasive aspergillosis in neutropenic patients is difficult. New reporter peptides can detect fungal proteases in serum, potentially improving early diagnosis and monitoring of invasive fungal infections.
Area of Science:
- Medical Mycology
- Diagnostic Microbiology
- Biochemistry
Background:
- Invasive mycoses, particularly invasive aspergillosis, pose a significant threat to neutropenic patients.
- Current diagnostic methods for invasive aspergillosis often lack sufficient sensitivity and specificity for early detection.
Purpose of the Study:
- To characterize specific protease activity of Aspergillus species (Aspergillus fumigatus and Aspergillus niger).
- To identify novel reporter peptides for improved diagnosis of invasive aspergillosis through protease profiling.
Main Methods:
- Analysis of Aspergillus culture supernatants, human serum, and mixtures.
- Systematic screening of a 360-peptide random library using fluorescence resonance energy transfer (FRET) to identify protease substrates.
Main Results:
- Identified numerous synthetic peptides selectively cleaved by fungal-specific proteases from Aspergillus species.
- Demonstrated the potential of these reporter peptides for analyzing protease activity in biological samples.
Conclusions:
- Developed novel FRET-based reporter peptides for detecting Aspergillus-specific protease activity.
- These reporter peptides show promise for enhancing the diagnosis and monitoring of invasive aspergillosis in serum specimens.
