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Gene therapy for ocular diseases meditated by ultrasound and microbubbles (Review).

Wan C, Li F, Li H - Mol Med Rep (2015)

Bottom Line: Ultrasound‑targeted microbubble destruction (UTMD), with the advantages of high safety, repetitive applicability and tissue targeting, has become a potential strategy for gene‑ and drug delivery.High‑amplitude oscillations of microbubbles act as cavitation nuclei which can effectively focus ultrasound energy, produce oscillations and disruptions that increase the permeability of the cell membrane and create transient pores in the cell membrane.In addition, appropriately powered, focused ultrasound combined with microbubbles can induce a reversible disruption of the blood‑retinal barrier with no significant side effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Ultrasound, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, P.R. China.

ABSTRACT
The eye is an ideal target organ for gene therapy as it is easily accessible and immune‑privileged. With the increasing insight into the underlying molecular mechanisms of ocular diseases, gene therapy has been proposed as an effective approach. Successful gene therapy depends on efficient gene transfer to targeted cells to prove stable and prolonged gene expression with minimal toxicity. At present, the main hindrance regarding the clinical application of gene therapy is not the lack of an ideal gene, but rather the lack of a safe and efficient method to selectively deliver genes to target cells and tissues. Ultrasound‑targeted microbubble destruction (UTMD), with the advantages of high safety, repetitive applicability and tissue targeting, has become a potential strategy for gene‑ and drug delivery. When gene‑loaded microbubbles are injected, UTMD is able to enhance the transport of the gene to the targeted cells. High‑amplitude oscillations of microbubbles act as cavitation nuclei which can effectively focus ultrasound energy, produce oscillations and disruptions that increase the permeability of the cell membrane and create transient pores in the cell membrane. Thereby, the efficiency of gene therapy can be significantly improved. The UTMD‑mediated gene delivery system has been widely used in pre‑clinical studies to enhance gene expression in a site‑specific manner in a variety of organs. With reasonable application, the effects of sonoporation can be spatially and temporally controlled to improve localized tissue deposition of gene complexes for ocular gene therapy applications. In addition, appropriately powered, focused ultrasound combined with microbubbles can induce a reversible disruption of the blood‑retinal barrier with no significant side effects. The present review discusses the current status of gene therapy of ocular diseases as well as studies on gene therapy of ocular diseases meditated by UTMD.

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Localization of reporter proteins in the ciliary region. (A-E) Localization of β-galactosidase activity after injection of pVAX1-LacZ plasmid mixed with microbubbles (A, B, D and E) with sonoporation or (C and F) without sonoporation. (A and D) Staining with hematoxylin and eosin allowed localization of the ciliary muscle on slides directly mounted in glycerol/phosphate-buffered saline. (B and E) β-galactosidase activity was detected in muscle cells (arrows) and in a small number of cells around the ciliary body (arrow heads). (C and F) No detectable β-galactosidase activity was present in the ciliary region without ultrasound application, except in the corneal epithelium, where staining was considered to be non-specific in all samples. (G-I) GFP was detected in (H and I) the fibers of the ciliary muscle (white arrows) and (I) in a small number of cells around the ciliary body (white arrowheads). No GFP-positive cells were observed in the control eyes (G). Scale bars, 100 mm. Image taken from Kowalczuk et al (78). cb, ciliary body; cm, ciliary muscle; GFP, green fluorescence protein.
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f8-mmr-12-04-4803: Localization of reporter proteins in the ciliary region. (A-E) Localization of β-galactosidase activity after injection of pVAX1-LacZ plasmid mixed with microbubbles (A, B, D and E) with sonoporation or (C and F) without sonoporation. (A and D) Staining with hematoxylin and eosin allowed localization of the ciliary muscle on slides directly mounted in glycerol/phosphate-buffered saline. (B and E) β-galactosidase activity was detected in muscle cells (arrows) and in a small number of cells around the ciliary body (arrow heads). (C and F) No detectable β-galactosidase activity was present in the ciliary region without ultrasound application, except in the corneal epithelium, where staining was considered to be non-specific in all samples. (G-I) GFP was detected in (H and I) the fibers of the ciliary muscle (white arrows) and (I) in a small number of cells around the ciliary body (white arrowheads). No GFP-positive cells were observed in the control eyes (G). Scale bars, 100 mm. Image taken from Kowalczuk et al (78). cb, ciliary body; cm, ciliary muscle; GFP, green fluorescence protein.

Mentions: Kowalczuk et al (78) assessed the application of low- intensity ultrasound combined with commercial microbubbles to transfect the ciliary muscle of rat eyes. The ultrasound settings applied were as follows: 1 MHz, 2 W/cm2 and a 50% duty cycle of 2 min. At 1 week, the ultrasound + microbubble treatment produced a significant increase in luminescence compared with that in the control eyes injected with plasmid only, with or without microbubbles. The reporter proteins were localized in the ciliary muscle as indicated by histochemical analysis (Fig. 8). At 1 month, all groups showed a significant decrease in luciferase activity. A rise in lens and ciliary muscle temperature was detected during the procedure; however, this did not result in any observable damage at 1 and 8 days. This study demonstrated that the ocular ciliary muscle can be targeted by DNA sonoporation, allowing for protein secretion into the ocular sphere. Sonoporation targeted to ciliary muscles has potential as a non-viral gene delivery procedure for the treatment of various ocular diseases.


Gene therapy for ocular diseases meditated by ultrasound and microbubbles (Review).

Wan C, Li F, Li H - Mol Med Rep (2015)

Localization of reporter proteins in the ciliary region. (A-E) Localization of β-galactosidase activity after injection of pVAX1-LacZ plasmid mixed with microbubbles (A, B, D and E) with sonoporation or (C and F) without sonoporation. (A and D) Staining with hematoxylin and eosin allowed localization of the ciliary muscle on slides directly mounted in glycerol/phosphate-buffered saline. (B and E) β-galactosidase activity was detected in muscle cells (arrows) and in a small number of cells around the ciliary body (arrow heads). (C and F) No detectable β-galactosidase activity was present in the ciliary region without ultrasound application, except in the corneal epithelium, where staining was considered to be non-specific in all samples. (G-I) GFP was detected in (H and I) the fibers of the ciliary muscle (white arrows) and (I) in a small number of cells around the ciliary body (white arrowheads). No GFP-positive cells were observed in the control eyes (G). Scale bars, 100 mm. Image taken from Kowalczuk et al (78). cb, ciliary body; cm, ciliary muscle; GFP, green fluorescence protein.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581786&req=5

f8-mmr-12-04-4803: Localization of reporter proteins in the ciliary region. (A-E) Localization of β-galactosidase activity after injection of pVAX1-LacZ plasmid mixed with microbubbles (A, B, D and E) with sonoporation or (C and F) without sonoporation. (A and D) Staining with hematoxylin and eosin allowed localization of the ciliary muscle on slides directly mounted in glycerol/phosphate-buffered saline. (B and E) β-galactosidase activity was detected in muscle cells (arrows) and in a small number of cells around the ciliary body (arrow heads). (C and F) No detectable β-galactosidase activity was present in the ciliary region without ultrasound application, except in the corneal epithelium, where staining was considered to be non-specific in all samples. (G-I) GFP was detected in (H and I) the fibers of the ciliary muscle (white arrows) and (I) in a small number of cells around the ciliary body (white arrowheads). No GFP-positive cells were observed in the control eyes (G). Scale bars, 100 mm. Image taken from Kowalczuk et al (78). cb, ciliary body; cm, ciliary muscle; GFP, green fluorescence protein.
Mentions: Kowalczuk et al (78) assessed the application of low- intensity ultrasound combined with commercial microbubbles to transfect the ciliary muscle of rat eyes. The ultrasound settings applied were as follows: 1 MHz, 2 W/cm2 and a 50% duty cycle of 2 min. At 1 week, the ultrasound + microbubble treatment produced a significant increase in luminescence compared with that in the control eyes injected with plasmid only, with or without microbubbles. The reporter proteins were localized in the ciliary muscle as indicated by histochemical analysis (Fig. 8). At 1 month, all groups showed a significant decrease in luciferase activity. A rise in lens and ciliary muscle temperature was detected during the procedure; however, this did not result in any observable damage at 1 and 8 days. This study demonstrated that the ocular ciliary muscle can be targeted by DNA sonoporation, allowing for protein secretion into the ocular sphere. Sonoporation targeted to ciliary muscles has potential as a non-viral gene delivery procedure for the treatment of various ocular diseases.

Bottom Line: Ultrasound‑targeted microbubble destruction (UTMD), with the advantages of high safety, repetitive applicability and tissue targeting, has become a potential strategy for gene‑ and drug delivery.High‑amplitude oscillations of microbubbles act as cavitation nuclei which can effectively focus ultrasound energy, produce oscillations and disruptions that increase the permeability of the cell membrane and create transient pores in the cell membrane.In addition, appropriately powered, focused ultrasound combined with microbubbles can induce a reversible disruption of the blood‑retinal barrier with no significant side effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Ultrasound, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, P.R. China.

ABSTRACT
The eye is an ideal target organ for gene therapy as it is easily accessible and immune‑privileged. With the increasing insight into the underlying molecular mechanisms of ocular diseases, gene therapy has been proposed as an effective approach. Successful gene therapy depends on efficient gene transfer to targeted cells to prove stable and prolonged gene expression with minimal toxicity. At present, the main hindrance regarding the clinical application of gene therapy is not the lack of an ideal gene, but rather the lack of a safe and efficient method to selectively deliver genes to target cells and tissues. Ultrasound‑targeted microbubble destruction (UTMD), with the advantages of high safety, repetitive applicability and tissue targeting, has become a potential strategy for gene‑ and drug delivery. When gene‑loaded microbubbles are injected, UTMD is able to enhance the transport of the gene to the targeted cells. High‑amplitude oscillations of microbubbles act as cavitation nuclei which can effectively focus ultrasound energy, produce oscillations and disruptions that increase the permeability of the cell membrane and create transient pores in the cell membrane. Thereby, the efficiency of gene therapy can be significantly improved. The UTMD‑mediated gene delivery system has been widely used in pre‑clinical studies to enhance gene expression in a site‑specific manner in a variety of organs. With reasonable application, the effects of sonoporation can be spatially and temporally controlled to improve localized tissue deposition of gene complexes for ocular gene therapy applications. In addition, appropriately powered, focused ultrasound combined with microbubbles can induce a reversible disruption of the blood‑retinal barrier with no significant side effects. The present review discusses the current status of gene therapy of ocular diseases as well as studies on gene therapy of ocular diseases meditated by UTMD.

Show MeSH
Related in: MedlinePlus