Cell-autonomous innate immunity by proteasome-derived defence peptides.

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Proteasome-derived peptides were primarily known for antigen presentation in T cell immunity.
• The role of proteasomal degradation products in broader immune responses, particularly innate immunity, remained unclear.
• Antimicrobial peptides are crucial for first-line defense, but their generation mechanisms are not fully understood.

Purpose of the Study:

• To investigate the role of proteasomes in generating antimicrobial peptides.
• To explore the function of these peptides in combating bacterial infections.
• To uncover potential therapeutic applications of proteasome-derived peptides.

Main Methods:

• In silico prediction of proteasome cleavage sites to identify potential defense peptides.
• Analysis of proteasome composition and function during bacterial infection.
• In vitro and in vivo assays to evaluate the antimicrobial activity of identified peptides.

Main Results:

• Proteasomes constitutively and upon bacterial induction generate defense peptides that inhibit bacterial growth.
• These peptides function by disrupting bacterial membranes.
• In silico analysis predicted numerous cationic defense peptides derived from proteasomal degradation.
• Bacterial infection alters proteasome function, enhancing antimicrobial peptide generation through mechanisms like PSME3 recruitment and increased tryptic-like cleavage.

Conclusions:

• Proteasomes play a significant role in cell-autonomous innate immunity through the generation of antimicrobial peptides.
• Proteasome-derived peptides represent a previously overlooked class of immune effectors with potential therapeutic value.
• These findings open avenues for developing novel antibiotics from proteasome-cleaved peptides for treating infectious diseases.