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A two-stage poly(ethylenimine)-mediated cytotoxicity: implications for gene transfer/therapy
S Moein Moghimi1, Peter Symonds, J Clifford Murray
1Molecular Targeting and Polymer Toxicology Group, School of Pharmacy, University of Brighton, Brighton BN2 4GJ, UK. s.m.moghimi@brighton.ac.uk
Summary
Poly(ethylenimine) (PEI) causes cell death by damaging cell membranes and triggering apoptosis. Understanding PEI
Area of Science:
- Biomaterials Science
- Cell Biology
- Toxicology
Background:
- Poly(ethylenimine) (PEI) is widely used in gene therapy for its high transfection efficiency.
- The molecular mechanisms underlying PEI's cytotoxicity remain poorly understood.
Purpose of the Study:
- To elucidate the molecular basis of Poly(ethylenimine) (PEI) cytotoxicity.
- To investigate PEI-induced membrane damage and apoptosis in human cell lines.
Main Methods:
- Assessed membrane integrity via lactate dehydrogenase release and phosphatidylserine translocation.
- Investigated mitochondrial-mediated apoptosis by analyzing cytochrome c release, caspase 3 activation, and mitochondrial membrane potential.
- Utilized branched (25 kDa) and linear (750 kDa) PEI in Jurkat T cells, umbilical vein endothelial cells, and THLE3 hepatocyte-like cells.
Main Results:
- PEI induced Phase I necrotic-like changes within 30 minutes, characterized by membrane damage.
- PEI triggered Phase II apoptosis within 24 hours through mitochondrial pathway activation.
- PEI-induced mitochondrial outer membrane channel formation led to cytochrome c release and caspase activation.
Conclusions:
- PEI's cytotoxicity involves both immediate membrane damage and delayed apoptosis.
- Understanding PEI's toxicity mechanisms is crucial for optimizing gene therapy protocols.
- Findings inform the development of safer cationic polymer-delivery systems for drugs.