PMID- 12719260
OWN - NLM
STAT- MEDLINE
DCOM- 20040106
LR  - 20240314
IS  - 0006-3495 (Print)
IS  - 1542-0086 (Electronic)
IS  - 0006-3495 (Linking)
VI  - 84
IP  - 5
DP  - 2003 May
TI  - Three-dimensional imaging of lipid gene-carriers: membrane charge density 
      controls universal transfection behavior in lamellar cationic liposome-DNA 
      complexes.
PG  - 3307-16
AB  - Cationic liposomes (CLs) are used worldwide as gene vectors (carriers) in 
      nonviral clinical applications of gene delivery, albeit with unacceptably low 
      transfection efficiencies (TE). We present three-dimensional laser scanning 
      confocal microscopy studies revealing distinct interactions between CL-DNA 
      complexes, for both lamellar L(alpha)(C) and inverted hexagonal H(II)(C) 
      nanostructures, and mouse fibroblast cells. Confocal images of L(alpha)(C) 
      complexes in cells identified two regimes. For low membrane charge density 
      (sigma(M)), DNA remained trapped in CL-vectors. By contrast, for high sigma(M), 
      released DNA was observed in the cytoplasm, indicative of escape from endosomes 
      through fusion. Remarkably, firefly luciferase reporter gene studies in the 
      highly complex L(alpha)(C)-mammalian cell system revealed an unexpected 
      simplicity where, at a constant cationic to anionic charge ratio, TE data for 
      univalent and multivalent cationic lipids merged into a single curve as a 
      function of sigma(M), identifying it as a key universal parameter. The universal 
      curve for transfection by L(alpha)(C) complexes climbs exponentially over 
      approximately four decades with increasing sigma(M) below an optimal charge 
      density (sigma(M)(*)), and saturates for at a value rivaling the high 
      transfection efficiency of H(II)(C) complexes. In contrast, the transfection 
      efficiency of H(II)(C) complexes is independent of sigma(M). The exponential 
      dependence of TE on sigma(M) for L(alpha)(C) complexes, suggests the existence of 
      a kinetic barrier against endosomal fusion, where an increase in sigma(M) lowers 
      the barrier. In the saturated TE regime, for both L(alpha)(C) complexes and 
      H(II)(C), confocal microscopy reveals the dissociation of lipid and DNA. However, 
      the lipid-released DNA is observed to be in a condensed state, most likely with 
      oppositely charged macro-ion condensing agents from the cytoplasm, which remain 
      to be identified. Much of the observed bulk of condensed DNA may be 
      transcriptionally inactive and may determine the current limiting factor to 
      transfection by cationic lipid gene vectors.
FAU - Lin, Alison J
AU  - Lin AJ
AD  - Materials Department, Physics Department, and Biomolecular Science and 
      Engineering Program, University of California, Santa Barbara, CA 93106, USA.
FAU - Slack, Nelle L
AU  - Slack NL
FAU - Ahmad, Ayesha
AU  - Ahmad A
FAU - George, Cyril X
AU  - George CX
FAU - Samuel, Charles E
AU  - Samuel CE
FAU - Safinya, Cyrus R
AU  - Safinya CR
LA  - eng
GR  - R01 AI020611/AI/NIAID NIH HHS/United States
GR  - R37 AI012520/AI/NIAID NIH HHS/United States
GR  - R01 AI012520/AI/NIAID NIH HHS/United States
GR  - AI 12520/AI/NIAID NIH HHS/United States
GR  - GM 59288/GM/NIGMS NIH HHS/United States
GR  - AI 20611/AI/NIAID NIH HHS/United States
GR  - R01 GM059288/GM/NIGMS NIH HHS/United States
PT  - Comparative Study
PT  - Evaluation Study
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Biophys J
JT  - Biophysical journal
JID - 0370626
RN  - 0 (Lipid Bilayers)
RN  - 0 (Liposomes)
RN  - 0 (Macromolecular Substances)
RN  - 9007-49-2 (DNA)
SB  - IM
MH  - Animals
MH  - DNA/administration & dosage/*chemistry/*pharmacokinetics
MH  - Drug Delivery Systems/methods
MH  - Fibroblasts/chemistry/metabolism
MH  - Imaging, Three-Dimensional/*methods
MH  - Lipid Bilayers/chemistry/pharmacokinetics
MH  - Liposomes/administration & dosage/*chemistry/*pharmacokinetics
MH  - Macromolecular Substances
MH  - Mice
MH  - Microscopy, Confocal/*methods
MH  - Molecular Conformation
MH  - Nanotechnology/methods
MH  - Static Electricity
MH  - Transfection/*methods
PMC - PMC1302891
EDAT- 2003/04/30 05:00
MHDA- 2004/01/07 05:00
PMCR- 2004/05/01
CRDT- 2003/04/30 05:00
PHST- 2003/04/30 05:00 [pubmed]
PHST- 2004/01/07 05:00 [medline]
PHST- 2003/04/30 05:00 [entrez]
PHST- 2004/05/01 00:00 [pmc-release]
AID - S0006-3495(03)70055-1 [pii]
AID - 18283 [pii]
AID - 10.1016/S0006-3495(03)70055-1 [doi]
PST - ppublish
SO  - Biophys J. 2003 May;84(5):3307-16. doi: 10.1016/S0006-3495(03)70055-1.