Gene Therapy Restores Mfrp and Corrects Axial Eye Length

Vélez, Gabriel; Tsang, Stephen H.; Tsai, Yi‐Ting; Hsu, Chun‐Wei; Gore, Anuradha; Abdelhakim, Aliaa H.; Mahajan, MaryAnn; Silverman, Ronald H.; Sparrow, Janet R.; Bassuk, Alexander G.; Mahajan, Vinit B.

doi:10.1038/s41598-017-16275-8

Cited by 43 publications

(54 citation statements)

References 31 publications

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“…Rather, loss of function of this gene results in white spots apparent on retinal imaging (retinitis punctata albicans) but these have different origin from the phenotype we observe, and progress to photoreceptor degeneration. It has been reported that the Mfrp knockout mice have eyes that are slightly (but not statistically significantly) smaller, by about 2% in axial length 35 . Our analysis of the human-equivalent mouse Tmem98 mutations show that that neither have statistically significant size reductions, although the H196P line is ~7% shorter It is worth noting that different strains of mice have measurably different ocular size.…”

Section: Discussionmentioning

confidence: 93%

“…Instead both have the same recessive phenotype of white spots on the retina, which correlate with abnormal cells below the retina that stain with macrophage markers, and progress to photoreceptor degeneration. For the Mfrp rdx mutation, atrophy of the RPE was reported 33 and for Mfrp rd6 a modest ocular axial length reduction from about 2.87 to 2.83 mm was reported although apparently not statistically significant 35 . A screen for mice with increased intraocular pressure (IOP) found a splice mutation in the Prss56 gene predicted to produce a truncated protein 8 .…”

Section: Introductionmentioning

confidence: 94%

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Missense Mutations in the Human Nanophthalmos GeneTMEM98Cause Retinal Defects in the Mouse

Cross

McKie

Keighren

et al. 2019

Preprint

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20PURPOSE. We previously found a dominant mutation, Rwhs, causing white spots on the 21 retina accompanied by retinal folds. Here we identify the mutant gene to be Tmem98. In 22 humans, mutations in the orthologous gene cause nanophthalmos. We modelled these 23 mutations in mice and characterised the mutant eye phenotypes of these and Rwhs. 24 METHODS.The Rwhs mutation was identified to be a missense mutation in Tmem98 by 25 genetic mapping and sequencing. The human TMEM98 nanophthalmos missense mutations 26 were made in the mouse gene by CRISPR-Cas9. Eyes were examined by indirect 27 ophthalmoscopy and the retinas imaged using a retinal camera. Electroretinography was 28 used to study retinal function. Histology, immunohistochemistry and electron microscopy 29 techniques were used to study adult eyes. 30 RESULTS. An I135T mutation of Tmem98 causes the dominant Rwhs phenotype and is 31 perinatally lethal when homozygous. Two dominant missense mutations of TMEM98, A193P 32 and H196P are associated with human nanophthalmos. In the mouse these mutations cause 33 recessive retinal defects similar to the Rwhs phenotype, either alone or in combination with 34 each other, but do not cause nanophthalmos. The retinal folds did not affect retinal function 35 as assessed by electroretinography. Within the folds there was accumulation of disorganised 36 outer segment material as demonstrated by immunohistochemistry and electron microscopy, 37 and macrophages had infiltrated into these regions. 38 CONCLUSIONS. Mutations in the mouse orthologue of the human nanophthalmos gene 39 TMEM98 do not result in small eyes. Rather, there is localised disruption of the laminar 40 structure of the photoreceptors. 41 42

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Section: Discussionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 94%

Missense Mutations in the Human Nanophthalmos GeneTMEM98Cause Retinal Defects in the Mouse

Cross

McKie

Keighren

et al. 2019

Preprint

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“…The models had an RMSD of 0.41–0.66 Å for 74 Cɑ atoms. Models of the individual domains were then assembled using ab initio domain assembly in MODELLER to generate a model of the full‐length CAPN5 structure (Figure c; Velez, Tsang, Tsai, et al, ). Using this model, we were able to better visualize the location of LOF coding variants on CAPN5's domains (Figure d).…”

Section: Resultsmentioning

confidence: 99%

CAPN5 genetic inactivation phenotype supports therapeutic inhibition trials

et al. 2019

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Small molecule pharmacological inhibition of dominant human genetic disease is a feasible treatment that does not rely on the development of individual, patient-specific gene therapy vectors. However, the consequences of protein inhibition as a clinical therapeutic are not well-studied. In advance of human therapeutic trials for CAPN5 vitreoretinopathy, genetic inactivation can be used to infer the effect of protein inhibition in vivo. We created a photoreceptor-specific knockout (KO) mouse for Capn5 and compared the retinal phenotype to both wild-type and an existing Capn5 KO mouse model. In humans, CAPN5 loss-of-function (LOF) gene variants were ascertained in large exome databases from 60,706 unrelated subjects without severe disease phenotypes. Ocular examination of the retina of Capn5 KO mice by histology and electroretinography showed no significant abnormalities. In humans, there were 22 LOF CAPN5 variants located throughout the gene and in all major protein domains. Structural modeling of coding variants showed these LOF variants were nearby known disease-causing variants within the proteolytic core and in regions of high homology between human CAPN5 and 150 homologs, yet the LOF of CAPN5 was tolerated as opposed to gain-of-function disease-causing variants. These results indicate that localized inhibition of CAPN5 is a viable strategy for hyperactivating disease alleles.

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“…As described by Velez, et al, Eyes were enucleated from euthanized mice, by following along the limbus to create a puncture at the 12 o'clock position. 56 Each eye was then placed in a solution of 1:2x Karnovsky fixative for 24 hours. Following fixation, eyes underwent a saline wash and then dehydration to be embedded in paraffin.…”

Section: Histologymentioning

confidence: 99%

PKM2 ablation enhanced retinal function and survival in a preclinical model of retinitis pigmentosa

Zhang

Ryu

Levi

et al. 2019

Preprint

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ABSTRACTRetinitis pigmentosa (RP) is a neurodegenerative disorder that causes irreversible vision loss in over 1.5 million individuals world-wide. In this study, we demonstrate that a metabolic reprogramming can treat degeneration in a Pde6β preclinical model of RP. Pyruvate kinase M2 (PKM2) is a glycolytic enzyme that transfers phosphate from phosphoenolpyruvate (PEP) to adenosine diphosphate (ADP), promoting glucose catabolism. Ablation of PKM2 resulted in enhanced photoreceptor survival and function in Pde6β-mutated mice compared with those without ablation. Electroretinogram (ERG) analyses revealed that the maximum b-wave is on average greater in Pkm2 knockout mice than in mice with Pkm2 intact. These rescue phenotypes from Pkm2 ablation in a preclinical model of RP indicate that a metabolome reprogramming may be useful in treating RP.

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Gene Therapy Restores Mfrp and Corrects Axial Eye Length

Cited by 43 publications

References 31 publications

Missense Mutations in the Human Nanophthalmos GeneTMEM98Cause Retinal Defects in the Mouse

Missense Mutations in the Human Nanophthalmos GeneTMEM98Cause Retinal Defects in the Mouse

CAPN5 genetic inactivation phenotype supports therapeutic inhibition trials

PKM2 ablation enhanced retinal function and survival in a preclinical model of retinitis pigmentosa

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