scholarly journals Ciliary Genes arl13b, ahi1 and cc2d2a Differentially Modify Expression of Visual Acuity Phenotypes but do not Enhance Retinal Degeneration due to Mutation of cep290 in Zebrafish

2019 ◽  
Author(s):  
Emma M. Lessieur ◽  
Ping Song ◽  
Gabrielle C. Nivar ◽  
Ellen M. Piccillo ◽  
Joseph Fogerty ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Joubert Syndrome ◽  
Genetic Modifiers ◽  
Photoreceptor Degeneration ◽  
Optokinetic Response ◽  
Bardet Biedl Syndrome ◽  
Leber Congenital Amaurosis ◽  
Outer Segments ◽  
Rhodopsin Kinase

ABSTRACTMutations in the gene Centrosomal Protein 290 kDa (CEP290) result in multiple ciliopathies ranging from the neonatal lethal disorder Meckel-Gruber Syndrome to multi-systemic disorders such as Joubert Syndrome and Bardet-Biedl Syndrome to nonsyndromic diseases like Leber Congenital Amaurosis (LCA) and retinitis pigmentosa. Results from model organisms and human genetics studies, have suggest that mutations in genes encoding protein components of the transition zone (TZ) and other cilia-associated proteins can function as genetic modifiers and be a source for CEP290 pleiotropy. We investigated the zebrafish cep290fh297/fh297 mutant, which encodes a nonsense mutation (p.Q1217*). This mutant is viable as adults, exhibits scoliosis, and undergoes a slow, progressive cone degeneration. The cep290fh297/fh297 mutants showed partial mislocalization of the transmembrane protein rhodopsin but not of the prenylated proteins rhodopsin kinase (GRK1) or the rod transducin subunit GNB1. Surprisingly, photoreceptor degeneration did not trigger proliferation of Müller glia, but proliferation of rod progenitors in the outer nuclear layer was significantly increased. To determine if heterozygous mutations in other cilia genes could exacerbate retinal degeneration, we bred cep290fh297/fh297 mutants to arl13b, ahi1, and cc2d2a mutant zebrafish lines. While cep290fh297/fh297 mutants lacking a single allele of these genes did not exhibit accelerated photoreceptor degeneration, loss of one alleles of arl13b or ahi1 reduced visual performance in optokinetic response assays at 5 days post fertilization. Our results indicate that the cep290fh297/fh297 mutant is a useful model to study the role of genetic modifiers on photoreceptor degeneration in zebrafish and to explore how progressive photoreceptor degeneration influences regeneration in adult zebrafish.Nonstandard abbreviationsBBSBardet-Biedl SyndromeCOScone outer segmentsDpfDays post fertilizationGNB1rod transducin β subunitGRK1rhodopsin kinaseJTBSJoubert SyndromeLCALeber Congenital AmaurosisMKSMeckel SyndromeNPHPnephronophthisisOKRoptokinetic responsePNApeanut agglutinin lectinROSrod outer segmentsRP2Retinitis Pigmentosa 2

scholarly journals Early onset non-syndromic retinal degeneration due to variants in INPP5E: phenotypic expansion of the ciliary gene previously associated with Joubert syndrome

2020 ◽  
Author(s):  
Riccardo Sangermano ◽  
Iris Deitch ◽  
Virginie G Peter ◽  
Rola Ba-Abbad ◽  
Emily M Place ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Early Onset ◽  
Joubert Syndrome ◽  
Phenotypic Correlation ◽  
Cone Dystrophy ◽  
Genetic Modifiers ◽  
Retinal Degenerations ◽  
Pathogenic Variants ◽  
Systemic Disorder ◽  
The Impact

Purpose: Pathogenic variants in INPP5E cause Joubert syndrome, a systemic disorder that can manifest with retinal degeneration among other clinical features. We aimed to evaluate the role of INPP5E variants in non-syndromic inherited retinal degenerations (IRDs) of varying severity. Methods: Targeted or genome sequencing were performed in 12 unrelated non-syndromic IRD families from multiple research hospitals. Detailed clinical examination was conducted in all probands. The impact of new likely pathogenic variants was modeled on a tertiary INPP5E protein structure and all the new and published variants were analyzed for their deleteriousness and phenotypic correlation. Results: Fourteen INPP5E rare alleles were detected, 12 of which were novel. Retinal degeneration in all 12 probands was clinically distinguishable on the basis of onset and severity into Leber congenital amaurosis (n=4) and a milder, later-onset rod-cone dystrophy (n=8). Two probands showed mild ciliopathy features that resolved in childhood. Analysis of the combined impact of both alleles in syndromic and non-syndromic INPP5E patients did not reveal clear genotype-phenotype correlation, suggesting involvement of genetic modifiers. Conclusions: The study expands the phenotypic spectrum of disorders due to pathogenic variants in INPP5E and describes a new disease association with previously underdiagnosed forms of early-onset non-syndromic IRD.

Retinal Diseases with Ciliopathies

2021 ◽  
pp. 271-278
Keyword(s):  
Retinitis Pigmentosa ◽  
Outer Segment ◽  
Usher Syndrome ◽  
Joubert Syndrome ◽  
Retinal Diseases ◽  
Bardet Biedl Syndrome ◽  
Retinal Photoreceptors ◽  
Underlying Mechanisms ◽  
Larsson Syndrome ◽  
Functional Defects

Ciliopathies are a group of diseases that affects cells containing the cilia organel. Retinal involvement is frequent in ciliopathies. The outer segment of retinal photoreceptors is composed of the cilium. Functional defects limited to the photoreceptors cilia, in particular, are classified as non-syndromic ciliopathies like Leber congenital amaurosis and retinitis pigmentosa. Photoreceptor disease also manifests as a part of syndromic ciliopathies with the involvement of multiple tissues as Usher syndrome, Joubert syndrome, Meckel-Gruber syndrome, Senior-Loken syndrome, Sjögren-Larsson syndrome, Bardet-Biedl syndrome, and Alstrom syndrome. Underlying mechanisms of pathology remain largely unclear in these diseases. Symptoms are treated using current methods. This paper describes the pathogenesis, clinics, diagnosis, and treatment of retinal diseases occurring due to ciliopathy.

scholarly journals Cone Photoreceptor Degeneration and Neuroinflammation in the Zebrafish Bardet-Biedl Syndrome 2 (bbs2) Mutant Does Not Lead to Retinal Regeneration

2020 ◽  
Vol 8 ◽  
Author(s):  
Ping Song ◽  
Joseph Fogerty ◽  
Lauren T. Cianciolo ◽  
Rachel Stupay ◽  
Brian D. Perkins
Keyword(s):  
Cell Proliferation ◽  
Inflammatory Response ◽  
Retinal Degeneration ◽  
Autosomal Recessive Disorder ◽  
Müller Cell ◽  
Cone Photoreceptor ◽  
Photoreceptor Degeneration ◽  
Retinal Regeneration ◽  
Bardet Biedl Syndrome ◽  
Muller Cell

Bardet-Biedl syndrome (BBS) is a heterogeneous and pleiotropic autosomal recessive disorder characterized by obesity, retinal degeneration, polydactyly, renal dysfunction, and mental retardation. BBS results from defects in primary and sensory cilia. Mutations in 21 genes have been linked to BBS and proteins encoded by 8 of these genes form a multiprotein complex termed the BBSome. Mutations in BBS2, a component of the BBSome, result in BBS as well as non-syndromic retinal degeneration in humans and rod degeneration in mice, but the role of BBS2 in cone photoreceptor survival is not clear. We used zebrafish bbs2–/– mutants to better understand how loss of bbs2 leads to photoreceptor degeneration. Zebrafish bbs2–/– mutants exhibited impaired visual function as larvae and adult zebrafish underwent progressive cone photoreceptor degeneration. Cone degeneration was accompanied by increased numbers of activated microglia, indicating an inflammatory response. Zebrafish exhibit a robust ability to regenerate lost photoreceptors following retinal damage, yet cone degeneration and inflammation was insufficient to trigger robust Müller cell proliferation. In contrast, high intensity light damage stimulated Müller cell proliferation and photoreceptor regeneration in both wild-type and bbs2–/– mutants, although the bbs2–/– mutants could only restore cones to pre-damaged densities. In summary, these findings suggest that cone degeneration leads to an inflammatory response in the retina and that BBS2 is necessary for cone survival. The zebrafish bbs2 mutant also represents an ideal model to identify mechanisms that will enhance retinal regeneration in degenerating diseases.

scholarly journals Retinitis Pigmentosa Results in Neurodegeneration Concomitant With Neuroinflammation, Extracellular Matrix Disorganization and the Upregulation of Neuroprotective Pathways in Glial Cells and Neurons

2020 ◽  
Author(s):  
Christina B. Bielmeier ◽  
Saskia Roth ◽  
Sabrina I. Schmitt ◽  
Stefaniya K. Boneva ◽  
Anja Schlecht ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Molecular Mechanisms ◽  
Genetic Model ◽  
Immunofluorescent Staining ◽  
System Response ◽  
Photoreceptor Degeneration ◽  
The Impact

Abstract BackgroundHereditary retinal degenerations like retinitis pigmentosa (RP) are amongst the leading causes of blindness in younger patients. To enable in vivo investigation of cellular and molecular mechanisms responsible for photoreceptor cell death and to allow testing of therapeutic strategies that could prevent retinal degeneration, animal models have been created. Here, we in-depth characterized the transgenic VPP mouse model, a genetic model for autosomal dominant RP. MethodsWe examined the degree of photoreceptor degeneration and studied the impact of the VPP transgene-induced retinal degeneration on the transcriptome level of the retina using next generation RNA sequencing (RNASeq) analyses followed by weighted correlation network analysis (WGCNA). We furthermore identified cellular subpopulations responsible for some of the observed dysregulations using in situ hybridizations, immunofluorescent staining and 3D reconstruction. ResultsOne month-old VPP mice showed a significantly higher number of apoptotic photoreceptor cells that resulted in a significantly thinner ONL in three months-old VPP mice, concomitant with an increase in reactivity of microglia and Müller cells. By RNASeq analysis we identified 9,256 dysregulated genes and six significantly associated gene modules in the subsequently performed WGCNA. Gene ontology enrichment showed, amongst others, dysregulation of TGF-β regulated extracellular matrix organization, factors of the (ocular) immune system/response and apoptosis. ConclusionThe predominant effect pointed towards induction of neuroinflammation and the upregulation of neuroprotective pathways like TGF-β, G-protein activated and VEGF signaling that were significantly associated with the VPP transgene-induced photoreceptor degeneration. Thus, modulation of these processes might represent new therapeutic options to delay the degeneration of photoreceptors in diseases like RP.

scholarly journals The bacterial toxin CNF1 as a tool to induce retinal degeneration reminiscent of retinitis pigmentosa

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Viviana Guadagni ◽  
Chiara Cerri ◽  
Ilaria Piano ◽  
Elena Novelli ◽  
Claudia Gargini ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Rho Gtpase ◽  
Bacterial Toxin ◽  
Postnatal Life ◽  
Rodent Models ◽  
Photoreceptor Degeneration ◽  
Large Animals ◽  
Surgical Treatments ◽  
Cytotoxic Necrotizing Factor 1

Abstract Retinitis pigmentosa (RP) comprises a group of inherited pathologies characterized by progressive photoreceptor degeneration. In rodent models of RP, expression of defective genes and retinal degeneration usually manifest during the first weeks of postnatal life, making it difficult to distinguish consequences of primary genetic defects from abnormalities in retinal development. Moreover, mouse eyes are small and not always adequate to test pharmacological and surgical treatments. An inducible paradigm of retinal degeneration potentially extensible to large animals is therefore desirable. Starting from the serendipitous observation that intraocular injections of a Rho GTPase activator, the bacterial toxin Cytotoxic Necrotizing Factor 1 (CNF1), lead to retinal degeneration, we implemented an inducible model recapitulating most of the key features of Retinitis Pigmentosa. The model also unmasks an intrinsic vulnerability of photoreceptors to the mechanism of CNF1 action, indicating still unexplored molecular pathways potentially leading to the death of these cells in inherited forms of retinal degeneration.

scholarly journals Transcriptional Profiling Identifies Upregulation of Neuroprotective Pathways in Retinitis Pigmentosa

2021 ◽  
Vol 22 (12) ◽  
pp. 6307
Author(s):  
Christina B. Bielmeier ◽  
Saskia Roth ◽  
Sabrina I. Schmitt ◽  
Stefaniya K. Boneva ◽  
Anja Schlecht ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Signaling Pathways ◽  
Retinal Degeneration ◽  
G Protein ◽  
Molecular Mechanisms ◽  
System Response ◽  
Photoreceptor Degeneration ◽  
Vegf Signaling ◽  
The Impact

Hereditary retinal degenerations like retinitis pigmentosa (RP) are among the leading causes of blindness in younger patients. To enable in vivo investigation of cellular and molecular mechanisms responsible for photoreceptor cell death and to allow testing of therapeutic strategies that could prevent retinal degeneration, animal models have been created. In this study, we deeply characterized the transcriptional profile of mice carrying the transgene rhodopsin V20G/P23H/P27L (VPP), which is a model for autosomal dominant RP. We examined the degree of photoreceptor degeneration and studied the impact of the VPP transgene-induced retinal degeneration on the transcriptome level of the retina using next generation RNA sequencing (RNASeq) analyses followed by weighted correlation network analysis (WGCNA). We furthermore identified cellular subpopulations responsible for some of the observed dysregulations using in situ hybridizations, immunofluorescence staining, and 3D reconstruction. Using RNASeq analysis, we identified 9256 dysregulated genes and six significantly associated gene modules in the subsequently performed WGCNA. Gene ontology enrichment showed, among others, dysregulation of genes involved in TGF-β regulated extracellular matrix organization, the (ocular) immune system/response, and cellular homeostasis. Moreover, heatmaps confirmed clustering of significantly dysregulated genes coding for components of the TGF-β, G-protein activated, and VEGF signaling pathway. 3D reconstructions of immunostained/in situ hybridized sections revealed retinal neurons and Müller cells as the major cellular population expressing representative components of these signaling pathways. The predominant effect of VPP-induced photoreceptor degeneration pointed towards induction of neuroinflammation and the upregulation of neuroprotective pathways like TGF-β, G-protein activated, and VEGF signaling. Thus, modulation of these processes and signaling pathways might represent new therapeutic options to delay the degeneration of photoreceptors in diseases like RP.

scholarly journals TUDCA Slows Retinal Degeneration in Two Different Mouse Models of Retinitis Pigmentosa and Prevents Obesity in Bardet-Biedl Syndrome Type 1 Mice

2012 ◽  
Vol 53 (1) ◽  
pp. 100 ◽  
Author(s):  
Arlene V. Drack ◽  
Alina V. Dumitrescu ◽  
Sajag Bhattarai ◽  
Daniel Gratie ◽  
Edwin M. Stone ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Mouse Models ◽  
Syndrome Type ◽  
Bardet Biedl Syndrome

Crumbs homologue 1 in polarity and blindness

2004 ◽  
Vol 32 (5) ◽  
pp. 828-830 ◽  
Author(s):  
J. Meuleman ◽  
S.A. van de Pavert ◽  
J. Wijnholds
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Cell Polarity ◽  
Current Knowledge ◽  
Leber Congenital Amaurosis ◽  
Retinal Dystrophies

Several retinal dystrophies, including retinitis pigmentosa type 12 and Leber congenital amaurosis, are caused by a large variety of mutations in the CRB1 (Crumbs homologue 1) gene. This discovery led to an increased focus on the function of CRB1 and the Drosophila homologue Crumbs. In the present study, we review the current knowledge on Crumbs and its vertebrate homologues, their function in cell polarity and their pathogenicity in retinal degeneration.

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