Biomedical Engineering Reference
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Fig. 7
(
a
) Liposome uptake and internalization of APC cultures incubated for 60 min with
Rh-labeled plain-L and TATp-L (100×); (
b
), APC culture fluorescence microscopy 48 h post
transfection with EGFP (40×).
1
: bright field,
2
: rh filter,
3
: Hoechst,
4
: EGFP (Modified from
Pappalardo et al.
2009
)
TATp-L-based lipoplexes significantly enhanced both the uptake and transfection
of APC (Fig.
7
) (Pappalardo et al.
2009
).
We recently reported a double-targeted delivery system simultaneously capable
of extracellular accumulation and intracellular penetration for gene therapy in the
treatment of myocardial ischemia. We used low cationic liposome-plasmid DNA
complexes (lipoplexes) modified with TATp and/or with monoclonal anti-myosin
monoclonal antibody 2G4 (mAb 2G4) specific toward cardiac myosin, for targeted
gene delivery to ischemic myocardium.
In vitro
transfection of both normoxic and
hypoxic cardiomyocytes was enhanced by the presence of TATp determined by
fluorescence microscopy and ELISA. The enhanced transfection with TATp-
lipoplexes indicated that intracellular delivery mediated by TATp played an impor-
tant role in the transfection of hypoxic as well as normoxic cells. The
in vitro
transfection was further enhanced by the additional modification with mAb 2G4
antibody in the case of hypoxic, but not normoxic cardiomyocytes. This can be
explained by the additional mAb 2G4-mediated targeted delivery of the lipoplexes
to the hypoxic cells because of the better binding of the lipoplexes with the
hypoxically damaged cells due to exposure of intracellular cardiac myosin.
However, we did not observe a synergism between TATp and mAb 2G4 ligands
under our experimental conditions. In
in vivo
experiments, we clearly demon-
strated an increased accumulation of mAb 2G4-modified TATp lipoplexes in the
ischemic rat myocardium and significantly enhanced transfection of cardiomyo-
cytes in the ischemic zone. Thus, the genetic transformation of normoxic and
hypoxic cardiomyocytes can be enhanced by using lipoplexes modified with TATp
and/or mAb 2G4 (Ko et al.
2009
).
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