An osmolarity dependent mechanism partially ameliorates retinal cysts and rescues cone function in a mouse model of X-linked retinoschisis.

Introduction: X-linked retinoschisis (XLRS) is a vitreoretinal dystrophy caused by gene mutations which disrupt retinoschisin-1 (RS1) function. Vital for retinal architecture, the absence of functional RS1 leads to the development of intraretinal cysts. Intravitreal injection of a gene therapy for treating XLRS caused ocular inflammation in high dose groups in a phase I/II clinical trial.

Investigating the role of Caspase-1 in a mouse model of Juvenile X-linked Retinoschisis.

Purpose: Previous studies have reported Caspase-1 () is upregulated in mouse models of Juvenile X-linked Retinoschisis (XLRS), however no functional role for in disease progression has been identified. We performed electroretinogram (ERG) and standardized optical coherence tomography (OCT) in mice deficient in the Retinoschisin-1 () and and Caspase-11 genes (-KO ) to test the hypothesis that may play a role in disease evolution and or severity of disease. Currently, no studies have ventured to investigate the longer-term effects of on phenotypic severity and disease progression over time in XLRS, and specifically the effect on electroretinogram.

A visually guided swim assay for mouse models of human retinal disease recapitulates the multi-luminance mobility test in humans.

Purpose: The purpose of this study was to develop a visually guided swim assay (VGSA) for measuring vision in mouse retinal disease models comparable to the multi-luminance mobility test (MLMT) utilized in human clinical trials.

Methods: Three mouse retinal disease models were studied: Bardet-Biedl syndrome type 1 (), = 5; Bardet-Biedl syndrome type 10 (), = 11; and X linked retinoschisis (retinoschisin knockout; KO), = 5. Controls were normally-sighted mice, = 10.

Subretinal gene therapy delays vision loss in a Bardet-Biedl Syndrome type 10 mouse model.

Blindness in Bardet-Biedl syndrome (BBS) is caused by dysfunction and loss of photoreceptor cells in the retina. , mutations of which account for approximately 21% of all BBS cases, encodes a chaperonin protein indispensable for the assembly of the BBSome, a cargo adaptor important for ciliary trafficking. The loss of BBSome function in the eye causes a reduced light sensitivity of photoreceptor cells, photoreceptor ciliary malformation, dysfunctional ciliary trafficking, and photoreceptor cell death.

AAV2/4-RS1 gene therapy in the retinoschisin knockout mouse model of X-linked retinoschisis.

Objective: To evaluate efficacy of a novel adeno-associated virus (AAV) vector, AAV2/4-RS1, for retinal rescue in the retinoschisin knockout (Rs1-KO) mouse model of X-linked retinoschisis (XLRS). Brinzolamide (Azopt®), a carbonic anhydrase inhibitor, was tested for its ability to potentiate the effects of AAV2/4-RS1.

Methods: AAV2/4-RS1 with a cytomegalovirus (CMV) promoter (2x1012 viral genomes/mL) was delivered to Rs1-KO mice via intravitreal (N = 5; 1μL) or subretinal (N = 21; 2μL) injections at postnatal day 60-90.

Electroretinogram abnormalities in FKRP-related limb-girdle muscular dystrophy (LGMDR9).

Background: Dystroglycanopathies are a heterogeneous group of membrane-related muscular dystrophies. The dystroglycanopathy phenotype includes a spectrum of severity ranging from severe congenital muscular dystrophy to adult-onset limb-girdle muscular dystrophy (LGMD). LGMDR9 is a dystroglycanopathy caused by mutations in the FKRP gene.

Progressive retinal degeneration of rods and cones in a Bardet-Biedl syndrome type 10 mouse model.

Bardet-Biedl syndrome (BBS) is a multi-organ autosomal-recessive disorder caused by mutations in at least 22 different genes. A constant feature is early-onset retinal degeneration leading to blindness. Among the most common forms is BBS type 10 (BBS10), which is caused by mutations in a gene encoding a chaperonin-like protein.

Endothelial BBSome is essential for vascular, metabolic, and retinal functions.

Objectives: Endothelial cells that line the entire vascular system play a pivotal role in the control of various physiological processes, including metabolism. Additionally, endothelial dysfunction is associated with many pathological conditions, including obesity. Here, we assessed the role of the BBSome, a protein complex composed of eight Bardet-Biedl syndrome (BBS) proteins in endothelial cells.

Clinical albinism score, presence of nystagmus and optic nerves defects are correlated with visual outcome in patients with oculocutaneous albinism.

To correlate clinical features, molecular genetic findings, and visual acuity in a cohort of patients clinically diagnosed with oculocutaneous albinism. Retrospective chart review 58 charts met the inclusion criteria. Clinical examination, ancillary testing, and molecular genetic diagnoses were extracted.

Correlation between electroretinography, foveal anatomy and visual acuity in albinism.

Background: Albinism patients have poor visual acuity in addition to hypopigmentation. Their foveal anatomy is abnormal, but correlation with function is incompletely understood. This study correlates retinal electrophysiology, visual acuity and optical coherence tomography (OCT) anatomy in albinism patients and compares with age-similar controls.

αδ-4 Is Required for the Molecular and Structural Organization of Rod and Cone Photoreceptor Synapses.

αδ-4 is an auxiliary subunit of voltage-gated Ca1.4 L-type channels that regulate the development and mature exocytotic function of the photoreceptor ribbon synapse. In humans, mutations in the gene encoding αδ-4 cause heterogeneous forms of vision impairment in humans, the underlying pathogenic mechanisms of which remain unclear.

Accumulation of non-outer segment proteins in the outer segment underlies photoreceptor degeneration in Bardet-Biedl syndrome.

Compartmentalization and polarized protein trafficking are essential for many cellular functions. The photoreceptor outer segment (OS) is a sensory compartment specialized for phototransduction, and it shares many features with primary cilia. As expected, mutations disrupting protein trafficking to cilia often disrupt protein trafficking to the OS and cause photoreceptor degeneration.

Vitritis in pediatric genetic retinal disorders.

Purpose: To determine which types of pediatric retinal degeneration are associated with inflammatory cells in the anterior vitreous.

Design: Retrospective, observational study in humans.

Methods: Retrospective chart review was performed for pediatric patients with suspected retinal degeneration presenting to a single examiner from 2008 to 2013.

RNA interference-based therapy for spinocerebellar ataxia type 7 retinal degeneration.

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurodegenerative disease characterized by loss of motor coordination and retinal degeneration with no current therapies in the clinic. The causative mutation is an expanded CAG repeat in the ataxin-7 gene whose mutant protein product causes cerebellar and brainstem degeneration and retinal cone-rod dystrophy. Here, we reduced the expression of both mutant and wildtype ataxin-7 in the SCA7 mouse retina by RNA interference and evaluated retinal function 23 weeks post injection.

TRIP8b is required for maximal expression of HCN1 in the mouse retina.

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are cation-selective channels present in retina, brain and heart. The activity of HCN channels contributes to signal integration, cell excitability and pacemaker activity. HCN1 channels expressed in photoreceptors participate in keeping light responses transient and are required for normal mesopic vision.

BBS mutations modify phenotypic expression of CEP290-related ciliopathies.

Ciliopathies are a group of heterogeneous disorders associated with ciliary dysfunction. Diseases in this group display considerable phenotypic variation within individual syndromes and overlapping phenotypes among clinically distinct disorders. Particularly, mutations in CEP290 cause phenotypically diverse ciliopathies ranging from isolated retinal degeneration, nephronophthisis and Joubert syndrome, to the neonatal lethal Meckel-Gruber syndrome.

Subretinal gene therapy of mice with Bardet-Biedl syndrome type 1.

Purpose: To study safety and efficacy of subretinal adeno-associated virus (AAV) vector AAV-Bbs1 injection for treatment of a mouse model of Bardet-Biedl syndrome type 1 (BBS1).

Methods: Constructs containing a wild-type (WT) Bbs1 gene with and without a FLAG tag in AAV2/5 vectors were generated. Viral genomes were delivered by subretinal injection to right eyes and sham injections to left eyes at postnatal day 30 (P30) to P60.

TUDCA slows retinal degeneration in two different mouse models of retinitis pigmentosa and prevents obesity in Bardet-Biedl syndrome type 1 mice.

Purpose: To evaluate and compare the protective effect of tauroursodeoxycholic acid (TUDCA) on photoreceptor degeneration in different models of retinal degeneration (RD) in mice.

Methods: Bbs(M390R/M390R) mice were injected subcutaneously twice a week, from P40 to P120, and rd10 mice were injected every 3 days from P6 to P38 with TUDCA or vehicle (0.15 M NaHCO(3)).