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AAV-Delivered Tulp1 Supplementation Therapy Targeting Photoreceptors Provides Minimal Benefit in Tulp1-/- Retinas.

ABSTRACT: With marketing approval of the first ocular gene therapy, and other gene therapies in clinical trial, treatments for inherited retinal degenerations (IRDs) have become a reality. Biallelic mutations in the tubby like protein 1 gene (TULP1) are causative of IRDs in humans; a mouse knock-out model (Tulp1-/-) is characterized by a similar disease phenotype. We developed a Tulp1 supplementation therapy for Tulp1-/- mice. Utilizing subretinal AAV2/5 delivery at postnatal day (p)2-3 and rhodopsin-kinase promoter (GRK1P) we targeted Tulp1 to photoreceptor cells exploring three doses, 2.2E9, 3.7E8, and 1.2E8 vgs. Tulp1 mRNA and TULP1 protein were assessed by RT-qPCR, western blot and immunocytochemistry, and visual function by electroretinography. Our results indicate that TULP1 was expressed in photoreceptors; achieved levels of Tulp1 mRNA and protein were similar to wild type levels at p20. However, the thickness of the outer nuclear layer (ONL) did not improve in treated Tulp1-/- mice. There was a small and transient electroretinography benefit in the treated retinas at 4 weeks of age (not observed by 6 weeks) when using 3.7E8 vg dose. Dark-adapted mixed rod and cone a- and b-wave amplitudes were 24.3 ± 13.5 ?V and 52.2 ± 31.7 ?V in treated Tulp1-/- mice, which were significantly different (p < 0.001, t-test), from those detected in untreated eyes (7.1 ± 7.0 ?V and 9.4 ± 15.1 ?V, respectively). Our results indicate that Tulp1 supplementation in photoreceptors may not be sufficient to provide robust benefit in Tulp1-/- mice. As such, further studies are required to fine tune the Tulp1 supplementation therapy, which, in principle, should rescue the Tulp1-/- phenotype.

SUBMITTER: Palfi A

PROVIDER: S-EPMC7482550 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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AAV-Delivered Tulp1 Supplementation Therapy Targeting Photoreceptors Provides Minimal Benefit in Tulp1-/- Retinas.

Palfi Arpad A Yesmambetov Adlet A Millington-Ward Sophia S Shortall Ciara C Humphries Pete P Kenna Paul F PF Chadderton Naomi N Farrar G Jane GJ

Frontiers in neuroscience 20200827

With marketing approval of the first ocular gene therapy, and other gene therapies in clinical trial, treatments for inherited retinal degenerations (IRDs) have become a reality. Biallelic mutations in the tubby like protein 1 gene (TULP1) are causative of IRDs in humans; a mouse knock-out model (Tulp1-/-) is characterized by a similar disease phenotype. We developed a Tulp1 supplementation therapy for Tulp1-/- mice. Utilizing subretinal AAV2/5 delivery at postnatal d ...[more]

PMID: 32973439

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Dataset Information

AAV-Delivered Tulp1 Supplementation Therapy Targeting Photoreceptors Provides Minimal Benefit in Tulp1-/- Retinas.

Publications

AAV-Delivered <i>Tulp1</i> Supplementation Therapy Targeting Photoreceptors Provides Minimal Benefit in <i>Tulp1-/-</i> Retinas.

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