Surgical Removal of Internal Limiting Membrane and Layering of AAV Vector on the Retina Under Air Enhances Gene Transfection in a Nonhuman Primate

Teo, Kelvin Yi Chong; Lee, Shu Yen; Barathi, A.; Tun, Sai Bo Bo; Tan, Leng Seow; Constable, Ian J.

doi:10.1167/iovs.18-24333

Cited by 28 publications

(18 citation statements)

References 44 publications

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“…25,44 Surgical peeling of the ILM and vitrectomy to remove vitreous before intravitreal injections resulted in a localized, enhanced retinal transduction in nonhuman primate (NHP) retinas. 45,46 However, it remains to be established if ILM removal in diseased eyes in combination with intravitreal AAV injections poses additional inflammatory challenges that would need to be addressed in the clinic.…”

Section: Discussionmentioning

confidence: 99%

Gene Therapy Targeting the Inner Retina Rescues the Retinal Phenotype in a Mouse Model of CLN3 Batten Disease

Holthaus¹,

Aristorena²,

Maswood³

et al. 2020

Human Gene Therapy

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The neuronal ceroid lipofuscinoses (NCLs), often referred to as Batten disease, are inherited lysosomal storage disorders that represent the most common neurodegeneration during childhood. Symptoms include seizures, vision loss, motor and cognitive decline, and premature death. The development of brain-directed treatments for NCLs has made noteworthy progress in recent years. Clinical trials are currently ongoing or planned for different forms of the disease. Despite these promising advances, it is unlikely that therapeutic interventions targeting the brain will prevent loss of vision in patients as retinal cells remain untreated and will continue to degenerate. Here, we demonstrate that Cln3 Dex7/8 mice, a mouse model of CLN3 Batten disease with juvenile onset, suffer from a decline in inner retinal function resulting from the death of rod bipolar cells, interneurons vital for signal transmission from photoreceptors to ganglion cells in the retina. We also show that this ocular phenotype can be treated by adeno-associated virus (AAV)-mediated expression of CLN3 in cells of the inner retina, leading to significant survival of bipolar cells and preserved retinal function. In contrast, the treatment of photoreceptors, which are lost in patients at late disease stages, was not therapeutic in Cln3 Dex7/8 mice, underlining the notion that CLN3 disease is primarily a disease of the inner retina with secondary changes in the outer retina. These data indicate that bipolar cells play a central role in this disease and identify this cell type as an important target for ocular AAV-based gene therapies for CLN3 disease.

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Section: Discussionmentioning

confidence: 99%

Gene Therapy Targeting the Inner Retina Rescues the Retinal Phenotype in a Mouse Model of CLN3 Batten Disease

Holthaus¹,

Aristorena²,

Maswood³

et al. 2020

Human Gene Therapy

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“…Moreover, simple manipulations to the retina may enhance transduction efficiency in diabetic retinas. Removal of the internal limiting membrane51, 52 and laser pretreatment 14 have previously been reported to enhance AAV transduction efficiency in rodent retinas, and further studies are needed to reveal their role in enhancing AAV transduction in DR.…”

Section: Discussionmentioning

confidence: 99%

Adeno-Associated Viral Vector 2 and 9 Transduction Is Enhanced in Streptozotocin-Induced Diabetic Mouse Retina

Lee

Yang

Madrakhimov

et al. 2019

Molecular Therapy - Methods & Clinical Development

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Adeno-associated viruses (AAVs) are currently the most popular vector platform technology for ocular gene therapy. While transduction efficiency and tropism of intravitreally administered AAV has been fairly well established in various retinal conditions, its transduction pattern in diabetic retinas has not previously been characterized. Here, we describe the transduction efficiencies of four different AAV serotypes, AAV2, 5, 8, and 9, in streptozotocin (STZ)-induced diabetic mouse retinas after intravitreal injections, which differed according to the duration of diabetic induction. STZ was intraperitoneally injected into C57/B6 diabetic mice subjected to unilateral intravitreal injection of AAV2, AAV5, AAV8, and AAV9 packaged with EGFP. Significantly enhanced AAV2 and AAV9 transduction was observed in 2-month-old diabetic mouse retinas compared to the 2-week-old diabetic mouse retinas and nondiabetic, vector uninjected or injected retinas. Intravitreal injection of AAV5 or AAV8 serotype in 2-month- and 2-week-old diabetic mouse retinas did not show any significant vector transduction enhancement compared to the nondiabetic control retinas. The tropism of AAV2 and AAV9 in diabetic mouse retinas differed. AAV2 was transduced into various retinal cells, including Müller cells, microglia, retinal ganglion cells (RGCs), bipolar cells, horizontal cells, and amacrine cells, whereas AAV9 was effectively transduced only into RGC and horizontal cells. The expression levels of receptors and co-receptors for AAV2 and AAV9 were significantly increased in 2-month-old diabetic mouse retinas. The results of our study demonstrated that AAV2 and AAV9 may be the vector of choice in treating diabetic retinopathy (DR) with gene therapy, and DR-related retinal changes may improve AAV vector transduction efficiency.

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“…The ILM limits neuroretinal transduction by intravitreally-administered AAV vectors. Experimental enzymatic digestion, 32 surgical ILM peeling, 30,68 and sub-ILM injection 69 circumvent this barrier, though the latter two are likely not feasible in rodent eyes. Here, we demonstrate that enzymatic digestion of ECM proteins within the ILM enhances retinal neurite ingrowth of transplanted RGCs.…”

Section: Transplanted Rgc Neurite Engraftmentmentioning

confidence: 99%

“…Gene therapy studies show that the internal limiting membrane (ILM) is a major barrier to retinal neuronal transduction by intravitreally administered viral vectors. [30][31][32][33] The ILM is a basement membrane composed of extracellular matrix (ECM) proteins including laminin, collagen IV, perlecan, nidogen, and others. 34 Cellular interactions with the ILM play important developmental roles in retinal patterning of neurons, glia, and blood vessels.…”

Section: Introductionmentioning

confidence: 99%

Structural engraftment and topographic spacing of transplanted human stem cell-derived retinal ganglion cells

Zhang

Tuffy

Mertz

et al. 2020

Preprint

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Retinal ganglion cell (RGC) replacement and optic nerve regeneration hold potential for restoring vision lost to optic neuropathy. Following transplantation, RGCs must integrate into the neuroretinal circuitry in order to receive afferent visual signals for processing and transmission to central targets. To date, the efficiency of RGC retinal integration following transplantation has been limited. We sought to characterize spontaneous interactions between transplanted human embryonic stem cell-derived RGCs and the recipient mature mammalian retina, and to identify and overcome barriers to the structural integration of transplanted neurons. Using an in vitro model system, following transplantation directly onto the inner surface of organotypic mouse retinal explants, human RGC somas form compact clusters and extend bundled neurites that remain superficial to the neural retinal tissue, hindering any potential for afferent synaptogenesis. To enhance integration, we explored methods to increase the cellular permeability of the internal limiting membrane (ILM). Digestion of extracellular matrix components using proteolytic enzymes was titrated to achieve disruption of the ILM while minimizing retinal toxicity and preserving endogenous retinal glial reactivity. Such ILM disruption is associated with dispersion rather than clustering of transplanted RGC bodies and neurites, and with a marked increase in transplanted RGC neurite extension into retinal parenchyma. The ILM appears to be a barrier to afferent retinal connectivity by transplanted RGCs and its circumvention may be necessary for successful functional RGC replacement through transplantation.

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Surgical Removal of Internal Limiting Membrane and Layering of AAV Vector on the Retina Under Air Enhances Gene Transfection in a Nonhuman Primate

Abstract: ILM appears to be the predominate barrier to AAV transfection. An efficacious and safe method of AAV2 gene delivery, taking into account the potential need for repeat treatments, appears to be the surgical removal of ILM and layering of AAV under air.v.

Cited by 28 publications

References 44 publications

Gene Therapy Targeting the Inner Retina Rescues the Retinal Phenotype in a Mouse Model of CLN3 Batten Disease

Gene Therapy Targeting the Inner Retina Rescues the Retinal Phenotype in a Mouse Model of CLN3 Batten Disease

Adeno-Associated Viral Vector 2 and 9 Transduction Is Enhanced in Streptozotocin-Induced Diabetic Mouse Retina

Structural engraftment and topographic spacing of transplanted human stem cell-derived retinal ganglion cells

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