This study was supported by the Seoul National University Research Grant (800-20140542), the Pioneer Research Program of NRF/MEST (2012-0009544), and the Bio-Signal Analysis Technology Innovation Program of NRF/MEST (2009-0090895),&#160;and&#160;the Grant of NRF/MEST (2015M3A9E6028949).

All experiments on animals were performed in accordance with the Association for Research in Vision and Ophthalmology Statement for the Use of Animals in Ophthalmic and Vision Research, and the guidelines and regulations set forth by the Seoul National University Institutional Animal Care and Use Committee and Seoul National University Hospital Biosafety Committee.
1. Preparing Injection Kit and Viral Vectors
<ol>
	<li>Prepare the microliter syringe equipped with a 33 G blunt needle steriliz...

<ol>
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A., Roska, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+therapy+for+blindness.">Gene therapy for blindness.</a> Annu Rev Neurosci. 36, 467-488 (2013).</li><li>Allocca, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+adeno-associated+virus+serotypes+efficiently+transduce+murine+photoreceptors.">Novel adeno-associated virus serotypes efficiently transduce murine photoreceptors.</a> J Virol. 81 (20), 11372-11380 (2007).</li><li>Takahashi, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sustained+transduction+of+ocular+cells+with+a+bovine+immunodeficiency+viral+vector.">Sustained transduction of ocular cells with a bovine immunodeficiency viral vector.</a> Hum Gene Ther. 13 (11), 1305-1316 (2002).</li><li>Rolling, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+therapeutic+prospects+in+early+onset+of+severe+retinal+dystrophy:+restoration+of+vision+in+RPE65+Briard+dogs+using+an+AAV+serotype+4+vector+that+specifically+targets+the+retinal+pigmented+epithelium.">Gene therapeutic prospects in early onset of severe retinal dystrophy: restoration of vision in RPE65 Briard dogs using an AAV serotype 4 vector that specifically targets the retinal pigmented epithelium.</a> Bull Mem Acad R Med Belg. 161 (10-12), 497-508 (2006).</li><li>Le Meur, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Restoration+of+vision+in+RPE65-deficient+Briard+dogs+using+an+AAV+serotype+4+vector+that+specifically+targets+the+retinal+pigmented+epithelium.">Restoration of vision in RPE65-deficient Briard dogs using an AAV serotype 4 vector that specifically targets the retinal pigmented epithelium.</a> Gene Ther. 14 (4), 292-303 (2007).</li><li>Alexander, J. 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In this video article, we described the limbal-approach subretinal injection technique in detail with representative results of RPE/choroid/scleral flat-mount. This is an easy and convenient technique for subretinal injection of viral vectors into RPE. Direct visualization of bleb formation during the injection is an important step for accurate delivery for the beginners. There are some subretinal injection techniques introduced in Journal of Visualized Experiments8-10. Subretinal space is the potential space ...

In ophthalmology, gene therapy has emerged as the treatment modality in monogenic inherited retinopathies. There are inherited retinopathies associated with genes in retinal pigment epithelium (RPE) including Leber congenital amurosis1,2, retinitis pigmentosa3, and choroideremia4. The research field of gene therapy is expanding in both preclinical studies and clinical trials using viral vectors such as adeno-associated virus (AAV), lentivirus (LV) and adenovirus (Ad)5. Different viral vectors have different tropism in the retina. For a safe and effective gene therapy, viral vectors should be carefully selected according to target cells and target genes.
The route of gene delivery is also important for effective gene delivery to target cells, thus, it should be carefully chosen as well. The two most common methods for intraocular delivery of viral vectors are subretinal injection and intravitreal injection6. The latter, intravitreal injection, has been widely used for drug delivery to treat choroidal neovascularization in wet age-related macular degeneration (AMD) and macular edema in diabetic retinopathy7. Intravitreal route provides exposure of viral vectors to vitreous and inner&#160;retina, but the diffusion of the vectors to outer retina is limited. On the other hand, the subretinal route provides direct delivery of viral vectors to the potential space between retina and RPE, inducing a localized bleb. Therefore, subretinal injection is currently considered a more efficient route for targeting photoreceptor cells and RPE. In terms of surgical approach, pars plana is chosen as a safe area for intravitreal injection to avoid retinal damage in human patients. By simply modifying this approach to mice, we could inject viral vectors subretinally or intravireally via limbal approach.
In this video article, we demonstrate an easy and convenient method of subretinal injection of viral vectors into mice RPE. After single puncture at posterior to limbus with a 30 G 1/2 needle, a 33 G blunt needle equipped microliter syringe is inserted into the subretinal space via the limbal puncture site. The viral vectors of 1.5 - 2 &#181;l volume are injected to the potential space between retina and RPE inducing subretinal blebs. This procedure can be performed under direct visualization using surgical microscope. Repeated practice will guarantee replicable results even without direct visualization of the bleb formation. This will help the researchers to perform accurate and timesaving experiments for subretinal gene delivery in mice RPE.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>TWEEZERS DUMONT #5 11cm DUMOSTAR 0.1 x 0.06 mm TIPS</td>
			<td>WPI</td>
			<td>500233</td>
			<td></td>
		</tr>
		<tr>
			<td>VANNAS Scissors S/S, 105mm</td>
			<td>WPI</td>
			<td>555583S</td>
			<td></td>
		</tr>
		<tr>
			<td>33G Blunt needle</td>
			<td>WPI</td>
			<td>NF33BL-2</td>
			<td></td>
		</tr>
		<tr>
			<td>NanoFil Syringe, 10 microliter&#160;</td>
			<td>WPI</td>
			<td>NANOFIL</td>
			<td></td>
		</tr>
		<tr>
			<td>RPE-KIT</td>
			<td>WPI</td>
			<td>RPE-KIT</td>
			<td>For easy one hand injection</td>
		</tr>
		<tr>
			<td>30Gx1/2 (0.3mmx 13mm) BD PrecisionGlideTM Needle</td>
			<td>BD</td>
			<td>305107</td>
			<td>Initial puncture for subretinal injection</td>
		</tr>
		<tr>
			<td>Microscope Cover Glasses (No. 1 3 mm diameter)</td>
			<td>Warner Instruments</td>
			<td>64-0720&#160; (CS-3R)</td>
			<td></td>
		</tr>
		<tr>
			<td>Leica operating microscope</td>
			<td>Leica</td>
			<td>LM M80</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluoresecein microscope</td>
			<td>Nikon</td>
			<td>Eclipse 80i</td>
			<td></td>
		</tr>
		<tr>
			<td>Lentivirus</td>
			<td>Thermo scientific</td>
			<td>TMO.LV-Ctr</td>
			<td>Used to dilute vectors</td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Gibco</td>
			<td>10010-015</td>
			<td>Used to dilute vectors</td>
		</tr>
		<tr>
			<td>Troperin (Phenylephrin 0.5%-Tropicamide 0.5%)</td>
			<td>Hanmi</td>
			<td></td>
			<td>For dilation</td>
		</tr>
		<tr>
			<td>Proparacaine Hydrochloride Ophthalmic Solution USP, 0.5% (Sterile)</td>
			<td>Bausch&#38;Lomb</td>
			<td></td>
			<td>For topical anesthesia</td>
		</tr>
		<tr>
			<td>Healon GV OVD</td>
			<td>Abbott Medical Optics Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Zoletil 50 (tiletamine hypochloride and zolazepam hypochloride)</td>
			<td>Virbac</td>
			<td></td>
			<td>For general anesthesia</td>
		</tr>
		<tr>
			<td>Rompun&#174; injection (Xylazine HCl)</td>
			<td>Bayer</td>
			<td></td>
			<td>For general anesthesia</td>
		</tr>
	</tbody>
</table>

limbal approach-subretinal injection of viral vectors for gene therapy in mice retinal pigment epithelium

The eye is a small and enclosed organ which makes it an ideal target for gene therapy. Recently various strategies have been applied to gene therapy in retinopathies using non-viral and viral gene delivery to the retina and retinal pigment epithelium (RPE). Subretinal injection is the best approach to deliver viral vectors directly to RPE cells. Before the clinical trial of a gene therapy, it is inevitable to validate the efficacy of the therapy in animal models of various retinopathies. Thus, subretinal injection in mice becomes a fundamental technique for an ocular gene therapy. In this protocol, we provide the easy and replicable technique for subretinal injection of viral vectors to experimental mice. This technique is modified from the intravitreal injection, which is widely used technique in ophthalmology clinics. The representative results of RPE/choroid/scleral complex flat-mount will help to understand the efficacy of this technique and adjust the volume and titer of viral vectors for the extent of gene transduction.

To evaluate the efficacy of the subretinal injection on viral gene transduction by this protocol, we used commercially available LV vectors with CMV promoter expressing both GFP and RFP for the indicator. Eyes were enucleated after the appropriate time period according to the research purpose. For the representative results, eyes were enucleated 10 weeks and 20 weeks after subretinal injection. After complete removal of the retina using the method described above, the flat mount of RPE/choroid/sclera complex was evaluate...

Watch this Scientific Journal Video about Limbal Approach-Subretinal Injection of Viral Vectors for Gene Therapy in Mice Retinal Pigment Epithelium at JoVE.com

Limbal Approach-Subretinal Injection of Viral Vectors for Gene Therapy in Mice Retinal Pigment Epithelium

Subretinal injection is a surgical technique for effective gene delivery to retinal pigment epithelium in the mouse eye. Here we describe an easy and replicable method for subretinal injection of viral vectors to retinal pigment epithelium in experimental mice.

The eye is a small and enclosed organ which makes it an ideal target for gene therapy. Recently various strategies have been applied to gene therapy in ...

limbal-approach-subretinal-injection-viral-vectors-for-gene-therapy

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20.7K Views.  Seoul National University College of Medicine. Subretinal injection is a surgical technique for effective gene delivery to retinal pigment epithelium in the mouse eye. Here we describe an easy and replicable method for subretinal injection of viral vectors to retinal pigment epithelium in experimental mice.