Gene delivery with in-situ crosslinking polymer networks generates long-term systemic protein expression

Abstract

Two polyethylene oxide-based delivery systems comprised of reacting PEG polymers were designed for the delivery of DNA expression vectors. The polymers are formulated with the DNA and injected into the muscle, wherein a crosslinked matrix forms in-situ. The matrix resembles a viscous solution (formulation A) or a gel (formulation B). The reacting PEG polymers do not interact with, but entrap the DNA. The formation of the matrix does not affect the supercoiling of the incorporated DNA. The polymers are biocompatible and biodegradable due to the presence of hydrolytically labile bonds in one of the components. Measurement of degradation in vivo suggests that a significant amount of the polymer disappears from the injected muscle by 28 days post injection. Administration to mice of SEAP plasmid DNA formulated with the PEG polymers results in SEAP expression. Expression levels are similar to those of unformulated DNA, but the duration of gene expression is significantly longer in immunocompetent animals receiving the formulated DNA. Significantly lower anti-SEAP IgG titers are elicited by network-formulated DNA relative to unformulated DNA, even though expression levels are comparable. The data suggests that the matrix extends duration of expression by reducing the anti-SEAP immune response so that these delivery systems may be useful for prolonged gene expression following a single intramuscular injection.

Phase behavior and rheological properties of DNA–cationic polysaccharide mixtures

“…for gene transfer and gene expression). For instance, the gel-like mixtures containing DNA can be very useful in applications, which demand a sustained release (due to the reduction of the convection effects) and protection of DNA [22].…”

“…The formation of a physical network should stabilize and protect DNA from degradation, preventing a loss of DNA function and a poor control of DNA release in, for instance, DNA expression vectors. Cat-(HM)HEC/DNA formulations may be used to inject DNA into a tissue to form viscous solutions or gels that, in turn, control the expression rate of DNA [22]. The physical crosslinking demonstrated in our systems is controllable by composition and allows a control of the molecular kinetics as manifested in the variable viscosities and relaxation times.…”

“…Gels provide protection, stabilization and sustainable delivery of DNA, due to a controlled entrapment over time [22]. Generally, DNA gel formulations are chemically crosslinked.…”

Matrices and scaffolds for DNA delivery in tissue engineering

“…Targeting a cell population or anatomical location by injection or systemic delivery is complex, but direct delivery of the vector from the scaffold can localize transgene expression primarily to the implant site. In addition to localized delivery, the scaffold can protect the vector against extracellular barriers that reduce their therapeutic efficacy by protecting them from attack by immune responses or and limiting degradation by serum nucleases or proteases [50]. Biomaterials have been able to increase the half-life of viral vectors and reduce the immune response that normally targets the virus [51].…”

Cationic Nanomicelles for Delivery of Plasmids Encoding Interleukin-4 and Interleukin-10 for Prevention of Autoimmune Diabetes in Mice

“…However, a stable and effective gene transfer for sustained period is still questionable. The major drawback associated with the use of unformulated plasmid and viral based formulations is the short-term bioavailability of the bolus dose (18). The combined delivery of plasmid DNA encoding IL-4 and IL-10 using poly[gamma-(4-aminobutyl)-L-glycolic acid] (PAGA) polymer prevented the development of autoimmune diabetes in NOD mice (19).…”