10 min Rapid Fire International Peptide Symposium 2023

Re-engineering bacterial weapons for peptide delivery into tissue (#37)

Kait Clarke 1 , Akila Pilapitiya 1 , Lilian Hor 1 , Khoshnoor Jahan 1 , Sharon Tran 2 , Erinna Lee 2 , Doug Fairlie 2 , Begoña Heras 1 , Jason J Paxman 1
  1. Department of Biochemistry and Chemistry , La Trobe Institute for Molecular Science, La Trobe University , Melbourne, Victoria , Australia
  2. Department of Biochemistry and Chemistry, Olivia Newton-John Cancer Research Institute, Melbourne, Victoria, Australia

Human tissue still represents a barrier for the intracellular delivery of peptide/protein therapeutics. This presents a significant problem given that most therapeutic targets are inside the human cell, including 60% of all human proteins, the human genome along with intracellular pathogens. As such effective peptide/protein delivery systems are the answer to transform the area of peptide/protein therapeutics.

I have found that delivery tools already exist within a subgroup of autotransporter proteins from Gram-negative bacteria. This insight has been derived from our extensive research on characterising the structures and mechanisms of autotransporters1-4. The specialised autotransporters are the result of thousands of years of bacteria-human co-evolution. Through a simple single protein-based system, autotransporters transport themselves to the bacterial cell surface5. At this point there is a group of autotransporters that are able to enter human tissue via receptor-mediated endocytosis, where unlike other bacterial proteins that can enter human cells, these autotransporters are able to enter the human cytosol intact.

Taking advantage of these novel characteristics we have re-engineered autotransporters to carry and release both proteins and peptides into human cells. As a proof of concept we have delivered the 269 amino acid green fluorescent protein into human epithelial cells. We have since incorporated anti-cancer therapeutic peptide repeats into our carrier and shown dose-dependant delivery and killing of melanoma and lung cancer cells. We are now currently adapting our carrier to transport anti-viral peptides into human tissue for the treatment of viral infections such as dengue, respiratory syncytial and zika infections.

Overall, this technology has the capacity to efficiently and specifically transport a range of peptides and proteins into many types of human tissue for the treatment of diverse human diseases, to represent a paradigm shift in the delivery of therapeutics.

  1. Hor L, .,.,.,.,., Paxman JJ & Heras B (2023). Nature Commun. Mar 1;14(1):1163.
  2. Vo JL,.,.,.,.,.,.,.,.,.,., Paxman JJ & Heras B (2022). Nature npj Biofilms Microbiomes 8(1), 20.
  3. Paxman JJ et al., (2019). Nature Commun. Apr 29;10(1):1967.
  4. Heras, B.,.,., Paxman, J.J. et al., (2014). Proc Natl Acad Sci 111, 457-62.
  5. Clarke KR.,.,.,., Paxman JJ & Heras B (2022). Frontiers in Immunol. Jul 1;13:921272.