Biomedical Engineering Reference
In-Depth Information
Muscle
EP
T Cell
(-) EP
GFP
T Cell
APC
APC
Increased DNA
transfection
Muscle
Increased
inflammation
(+) EP
GFP
(a)
(b)
FIGURE 14.2
Electroporation. increases. DNA. transfection. and. inlammation.. (a). GFP. expression. plasmids. were. injected.
into. the. quadriceps. muscle. of. mice. with. or. without. electroporation.. (b). Cartoon. showing. the. dual. effect. of.
electroporation:.increased.DNA.transfection.and.inlammation..Electroporation.of.DNA.plasmids.leads.to.an.
increase.in.the.recruitment.of.antigen-presenting.cells,.B.cells,.and.T.cells.
However,.a.clear.limitation.in.the.early.clinical.evaluation.of.DNA.vaccines.was.limited.
gene.expression..So.how.was.the.ield.going.to.evolve.and.overcome.this.limitation.
Neumann.et.al..made.the.groundbreaking.observation.that.pulsing.cells.in.culture.with.
electric. currents. dramatically. improved. DNA.uptake,. leading. to.increased. gene.expres-
sion. 21 .And.applying.this.further,.in.1999,.Mir.et.al..demonstrated.that.electric.pulses.also.
improved. plasmid. uptake. in. vivo. 25 As. shown. in. Figure  14.2a,. gene. delivery. via. elec-
troporation leads.to.increased.DNA.expression.by.several.orders.of.magnitude.in.skeletal.
muscles.of.mice,.as.well.as.rats,.rabbits,.and.monkeys..These.observations,.coupled.with.
poor.immunogenicity.data.in.larger.animals,.transitioned.the.DNA.vaccine.ield.into.the.
electroporation.platform.
The.initial.study.that.illuminated.the.connection.between.electroporation.and.limited.
DNA.transfection.in.vivo was.from.Dupuis.et.al. 17 .These.authors.provided.lucid.data.show-
ing.increased.gene.expression.and.immune.responses.with.electroporation..One.of.the.
factors.that.contributed.to.increased.immune.response.is.the.increase.in.protein.expres-
sion;.clearly,.in.most.cases,.increased.antigen.translates.to.increased.immune.response.as.
a.result.of.increased.antigen.presentation.and.T.cell.activation..But.another.consequence.
of.pulsing.skeletal.muscles.with.electricity.may.be.involved;.upon.electroporation,.some.
of.the.muscle.cells.undergo.cell.death,.likely.from.irreversible.alterations.to.membrane.
physiology.. The. consequence. of. this. type. of. tissue. damage. is. inlammation,. likely. via.
sending.“danger”.signals.to.the.immune.system..Dying.cells,.typically.through.necrotic.
means,.release.various.proinlammatory.inducers,.such.as.HMGB1,.leading.to.maturation.
of.dendritic.cells.and.increased.antigen.presentation. 26 .As.a.result,.increased.muscle.dam-
age.from.electroporation.may.augment.ancillary.factors.to.promote.inlammation..In.fact,.
this.has.been.observed.experimentally:.Ahlen.et.al..reported.a.clear.increase.in.the.num-
ber.of.CD3 + .cells.at.the.site.of.injection 27 ;.Liu.et.al..reported.an.amazing.45-fold.increase.
Search WWH ::




Custom Search