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Published on: November 9, 2020
Cathepsin B-sensitive polymers for compartment-specific degradation and nucleic acid release
David S H Chu1, Russell N Johnson, Suzie H Pun
1Department of Bioengineering, University of Washington, Seattle, WA 98195, United States.
Summary
New peptide-based degradable cationic polymers show promise for nucleic acid delivery. These polymers, incorporating specific peptide linkers, demonstrate efficient DNA release and reduced toxicity in cellular studies.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Gene Delivery
Background:
- Degradable cationic polymers are crucial for in vivo nucleic acid delivery due to lower toxicity compared to non-degradable versions.
- Peptide linkers offer stability and specificity but are underexplored in nucleic acid delivery systems.
Purpose of the Study:
- To synthesize and evaluate enzymatically degradable peptide-N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers for nucleic acid delivery.
- To investigate the impact of peptide stereochemistry on polymer degradation and DNA release kinetics.
- To assess the in vitro transfection efficiency and cytotoxicity of the developed peptide-HPMA copolymers.
Main Methods:
- Synthesis of peptide-HPMA copolymers via RAFT polymerization, incorporating methacrylamido-terminated peptide macromonomers.
- Evaluation of copolymer degradation by cathepsin B, a key endosomal enzyme.
- Formation and characterization of polyplexes with DNA and assessment of DNA release kinetics.
- In vitro transfection studies in HeLa and NIH/3T3 cells to determine efficiency and toxicity.
Main Results:
- Peptide-HPMA copolymers with L-amino acids (pHCathK(10) and pHCath(D)K(10)) were rapidly degraded by cathepsin B within 1 hour.
- Polymers containing all D-amino acids (pH(D)Cath(D)K(10)) showed no degradation.
- Polyplexes formed with pHCathK(10) demonstrated DNA release within 4 hours, while others showed no release within 8 hours.
- Transfection efficiencies were comparable across copolymers, but pHCathK(10) exhibited lower cytotoxicity.
Conclusions:
- Enzymatically degradable peptide linkers can be successfully incorporated into HPMA copolymers for effective nucleic acid delivery.
- The stereochemistry of the peptide linker significantly influences the degradation profile and DNA release characteristics.
- The developed peptide-HPMA copolymers represent a promising platform for safer and more efficient gene delivery applications.
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