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Updated: May 27, 2026
08:25
Phage-mediated Delivery of Targeted sRNA Constructs to Knock Down Gene Expression in E. coli
Published on: March 20, 2016
Effective endogenous gene silencing mediated by pH responsive peptides proceeds via multiple pathways
Jenny K W Lam1, Wanling Liang, Yun Lan
1Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
Summary
pH responsive peptide vectors effectively deliver siRNA for gene silencing, showing comparable efficacy and lower toxicity than commercial non-viral vectors. Uptake mechanisms vary, with siRNA entry being cholesterol-dependent and DNA transfer clathrin-dependent.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Cationic amphipathic histidine-rich peptides demonstrate potential for delivering nucleic acids like plasmid DNA and small interfering RNA (siRNA).
- Understanding the pH-responsive mechanisms of these peptides is crucial for optimizing gene delivery and gene silencing applications.
Purpose of the Study:
- To investigate the pH-responsive siRNA delivery process mediated by cationic amphipathic histidine-rich peptides.
- To evaluate the efficacy of these peptides in mediating specific gene silencing of the GAPDH gene in MCF-7 and A549 cells.
- To compare the gene delivery and silencing capabilities of these peptides with plasmid DNA delivery and commercial non-viral vectors.
Main Methods:
- Utilized pH-responsive peptide vectors for gene delivery and silencing studies.
- Employed confocal live-cell imaging to track cellular uptake and endocytosis pathways.
- Assessed gene silencing efficacy by measuring GAPDH activity and expression.
- Investigated the role of endocytosis inhibitors to elucidate uptake mechanisms.
- Compared peptide performance against commercial non-viral vectors.
Main Results:
- Achieved substantial and selective reduction in GAPDH activity and expression using pH-responsive peptide vectors.
- Peptide-mediated delivery showed favorable efficacy and toxicity profiles compared to commercial non-viral vectors.
- Both plasmid DNA and siRNA were internalized via endocytosis, confirmed by live-cell imaging and inhibitor studies.
- siRNA uptake mediated by LAH4-L1 involved a cholesterol-dependent pathway, distinct from the clathrin-dependent endocytosis of DNA.
- Peptide specificity influenced siRNA entry routes and endosomal escape, with some peptides utilizing alternative mechanisms.
Conclusions:
- pH-responsive peptide vectors are effective tools for targeted gene silencing via siRNA delivery.
- The mechanism of cellular entry and endosomal processing is peptide-specific and influences the ultimate gene silencing outcome.
- These findings highlight the potential of rationally designed peptide vectors for advanced nucleic acid therapeutics.
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