| 1. |
- Arango-Gonzalez, Blanca, et al.
(författare)
-
Identification of a common non-apoptotic cell death mechanism in hereditary retinal degeneration.
- 2014
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
-
Tidskriftsartikel (refereegranskat)abstract
- Cell death in neurodegenerative diseases is often thought to be governed by apoptosis; however, an increasing body of evidence suggests the involvement of alternative cell death mechanisms in neuronal degeneration. We studied retinal neurodegeneration using 10 different animal models, covering all major groups of hereditary human blindness (rd1, rd2, rd10, Cngb1 KO, Rho KO, S334ter, P23H, Cnga3 KO, cpfl1, Rpe65 KO), by investigating metabolic processes relevant for different forms of cell death. We show that apoptosis plays only a minor role in the inherited forms of retinal neurodegeneration studied, where instead, a non-apoptotic degenerative mechanism common to all mutants is of major importance. Hallmark features of this pathway are activation of histone deacetylase, poly-ADP-ribose-polymerase, and calpain, as well as accumulation of cyclic guanosine monophosphate and poly-ADP-ribose. Our work thus demonstrates the prevalence of alternative cell death mechanisms in inherited retinal degeneration and provides a rational basis for the design of mutation-independent treatments.
|
|
| 2. |
- Bedoni, Nicola, et al.
(författare)
-
Mutations in the polyglutamylase gene TTLL5, expressed in photoreceptor cells and spermatozoa, are associated with cone-rod degeneration and reduced male fertility
- 2016
-
Ingår i: Human Molecular Genetics. - 0964-6906. ; 25:20, s. 4546-4555
-
Tidskriftsartikel (refereegranskat)abstract
- Hereditary retinal degenerations encompass a group of genetic diseases characterized by extreme clinical variability. Following next-generation sequencing and autozygome-based screening of patients presenting with a peculiar, recessive form of cone-dominated retinopathy, we identified five homozygous variants [p.(Asp594fs), p.(Gln117*), p.(Met712fs), p.(Ile756Phe), and p.(Glu543Lys)] in the polyglutamylase-encoding gene TTLL5, in eight patients from six families. The two male patients carrying truncating TTLL5 variants also displayed a substantial reduction in sperm motility and infertility, whereas those carrying missense changes were fertile. Defects in this polyglutamylase in humans have recently been associated with cone photoreceptor dystrophy, while mouse models carrying truncating mutations in the same gene also display reduced fertility in male animals. We examined the expression levels of TTLL5 in various human tissues and determined that this gene has multiple viable isoforms, being highly expressed in testis and retina. In addition, antibodies against TTLL5 stained the basal body of photoreceptor cells in rat and the centrosome of the spermatozoon flagellum in humans, suggesting a common mechanism of action in these two cell types. Taken together, our data indicate that mutations in TTLL5 delineate a novel, allele-specific syndrome causing defects in two as yet pathogenically unrelated functions, reproduction and vision.
|
|
| 3. |
- Farinelli, Pietro, et al.
(författare)
-
DNA methylation and differential gene regulation in photoreceptor cell death.
- 2014
-
Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa (RP) defines a group of inherited degenerative retinal diseases causing progressive loss of photoreceptors. To this day, RP is still untreatable and rational treatment development will require a thorough understanding of the underlying cell death mechanisms. Methylation of the DNA base cytosine by DNA methyltransferases (DNMTs) is an important epigenetic factor regulating gene expression, cell differentiation, cell death, and survival. Previous studies suggested an involvement of epigenetic mechanisms in RP, and in this study, increased cytosine methylation was detected in dying photoreceptors in the rd1, rd2, P23H, and S334ter rodent models for RP. Ultrastructural analysis of photoreceptor nuclear morphology in the rd1 mouse model for RP revealed a severely altered chromatin structure during retinal degeneration that coincided with an increased expression of the DNMT isozyme DNMT3a. To identify disease-specific differentially methylated DNA regions (DMRs) on a genomic level, we immunoprecipitated methylated DNA fragments and subsequently analyzed them with a targeted microarray. Genome-wide comparison of DMRs between rd1 and wild-type retina revealed hypermethylation of genes involved in cell death and survival as well as cell morphology and nervous system development. When correlating DMRs with gene expression data, we found that hypermethylation occurred alongside transcriptional repression. Consistently, motif analysis showed that binding sites of several important transcription factors for retinal physiology were hypermethylated in the mutant model, which also correlated with transcriptional silencing of their respective target genes. Finally, inhibition of DNMTs in rd1 organotypic retinal explants using decitabine resulted in a substantial reduction of photoreceptor cell death, suggesting inhibition of DNA methylation as a potential novel treatment in RP.
|
|
| 4. |
- Farinelli, Pietro, et al.
(författare)
-
Retinitis Pigmentosa: Over-expression of anti-ageing protein Klotho in degenerating photoreceptors.
- 2013
-
Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042.
-
Tidskriftsartikel (refereegranskat)abstract
- Retinitis Pigmentosa involves a hereditary degeneration of photoreceptors by as yet unresolved mechanisms. The secretable protein α-Klotho has a function related to ageing processes, and α-Klotho deficient mice have reduced lifespan and declining functions in several tissues. Here, we studied Klotho in connection with inherited photoreceptor degeneration. Increased nuclear immunostaining for α-Klotho protein was seen in degenerating photoreceptors in four different Retinitis Pigmentosa models (rd1, rd2 mice; P23H, S334ter rhodopsin mutant rats). Correspondingly, in rd1 retina α-Klotho mRNA expression was significantly upregulated. Moreover, immunostaining for another Klotho family protein, β-Klotho, also co-localised with degenerating rd1 photoreceptors. The rd1 retina displayed reduced levels of fibroblast growth factor (FGF) 15, a member of the FGF subfamily for which Klotho acts as a co-receptor. Exogenous α-Klotho protein added to retinal explant cultures did not affect cell death in rd1 retinae, but caused a severe layer disordering in wild-type retinae. Our work suggests Klotho as a novel player in the retina, with a clear connection to photoreceptor cell death as well as with an influence on retinal organization. This article is protected by copyright. All rights reserved.
|
|
| 5. |
- Kaur, Jasvir, et al.
(författare)
-
Calpain and PARP Activation during Photoreceptor Cell Death in P23H and S334ter Rhodopsin Mutant Rats
- 2011
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:7
-
Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa (RP) is a heterogeneous group of inherited neurodegenerative diseases affecting photoreceptors and causing blindness. Many human cases are caused by mutations in the rhodopsin gene. An important question regarding RP pathology is whether different genetic defects trigger the same or different cell death mechanisms. To answer this question, we analysed photoreceptor degeneration in P23H and S334ter transgenic rats carrying rhodopsin mutations that affect protein folding and sorting respectively. We found strong activation of calpain and poly(ADP-ribose) polymerase (PARP) in both mutants, concomitant with calpastatin down-regulation, increased oxidative DNA damage and accumulation of PAR polymers. These parameters were strictly correlated with the temporal progression of photoreceptor degeneration, mirroring earlier findings in the phosphodiesterase-6 mutant rd1 mouse, and suggesting execution of non-apoptotic cell death mechanisms. Interestingly, activation of caspases-3 and -9 and cytochrome c leakage-key events in apoptotic cell death-were observed only in the S334ter mutant, which also showed increased expression of PARP-1. The identification of the same metabolic markers triggered by different mutations in two different species suggests the existence of common cell death mechanisms, which is a major consideration for any mutation independent treatment.
|
|
| 6. |
- Nikopoulos, Konstantinos, et al.
(författare)
-
Mutations in CEP78 Cause Cone-Rod Dystrophy and Hearing Loss Associated with Primary-Cilia Defects
- 2016
-
Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 99:3, s. 770-776
-
Tidskriftsartikel (refereegranskat)abstract
- Cone-rod degeneration (CRD) belongs to the disease spectrum of retinal degenerations, a group of hereditary disorders characterized by an extreme clinical and genetic heterogeneity. It mainly differentiates from other retinal dystrophies, and in particular from the more frequent disease retinitis pigmentosa, because cone photoreceptors degenerate at a higher rate than rod photoreceptors, causing severe deficiency of central vision. After exome analysis of a cohort of individuals with CRD, we identified biallelic mutations in the orphan gene CEP78 in three subjects from two families: one from Greece and another from Sweden. The Greek subject, from the island of Crete, was homozygous for the c.499+1G>T (IVS3+1G>T) mutation in intron 3. The Swedish subjects, two siblings, were compound heterozygotes for the nearby mutation c.499+5G>A (IVS3+5G>A) and for the frameshift-causing variant c.633delC (p.Trp212Glyfs(∗)18). In addition to CRD, these three individuals had hearing loss or hearing deficit. Immunostaining highlighted the presence of CEP78 in the inner segments of retinal photoreceptors, predominantly of cones, and at the base of the primary cilium of fibroblasts. Interaction studies also showed that CEP78 binds to FAM161A, another ciliary protein associated with retinal degeneration. Finally, analysis of skin fibroblasts derived from affected individuals revealed abnormal ciliary morphology, as compared to that of control cells. Altogether, our data strongly suggest that mutations in CEP78 cause a previously undescribed clinical entity of a ciliary nature characterized by blindness and deafness but clearly distinct from Usher syndrome, a condition for which visual impairment is due to retinitis pigmentosa.
|
|
| 7. |
- Panneman, Daan M., et al.
(författare)
-
Cost-effective sequence analysis of 113 genes in 1,192 probands with retinitis pigmentosa and Leber congenital amaurosis
- 2023
-
Ingår i: Frontiers in cell and developmental biology. - : Frontiers Media SA. - 2296-634X. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) are two groups of inherited retinal diseases (IRDs) where the rod photoreceptors degenerate followed by the cone photoreceptors of the retina. A genetic diagnosis for IRDs is challenging since >280 genes are associated with these conditions. While whole exome sequencing (WES) is commonly used by diagnostic facilities, the costs and required infrastructure prevent its global applicability. Previous studies have shown the cost-effectiveness of sequence analysis using single molecule Molecular Inversion Probes (smMIPs) in a cohort of patients diagnosed with Stargardt disease and other maculopathies. Methods: Here, we introduce a smMIPs panel that targets the exons and splice sites of all currently known genes associated with RP and LCA, the entire RPE65 gene, known causative deep-intronic variants leading to pseudo-exons, and part of the RP17 region associated with autosomal dominant RP, by using a total of 16,812 smMIPs. The RP-LCA smMIPs panel was used to screen 1,192 probands from an international cohort of predominantly RP and LCA cases. Results and discussion: After genetic analysis, a diagnostic yield of 56% was obtained which is on par with results from WES analysis. The effectiveness and the reduced costs compared to WES renders the RP-LCA smMIPs panel a competitive approach to provide IRD patients with a genetic diagnosis, especially in countries with restricted access to genetic testing.
|
|
| 8. |
- Peter, Virginie G., et al.
(författare)
-
A novel missense variant in IDH3A causes autosomal recessive retinitis pigmentosa
- 2019
-
Ingår i: Ophthalmic Genetics. - : Informa UK Limited. - 1381-6810 .- 1744-5094. ; 40:2, s. 177-181
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Inherited retinal degenerations (IRDs) encompass a wide spectrum of genetic ocular diseases characterized by considerable genetic and clinical heterogeneity. Methods: Complete ophthalmic examination and next-generation sequencing. Results: We describe a patient with no family history of vision loss, who at the age of 28 years developed visual impairment consistent with a severe form of retinitis pigmentosa. Genetic testing by means of whole exome sequencing identified a homozygous variant in the gene IDH3A. To date, only three papers have reported mutations in IDH3A, in families with early-onset retinal degeneration with or without the presence of macular pseudocoloboma. Conclusion: This study highlights the importance of including this rarely-mutated gene in the molecular diagnostic set-ups for IRDs, and further delineates the phenotypic spectrum elicited by mutations in IDH3A.
|
|
| 9. |
- Sancho-Pelluz, J., et al.
(författare)
-
Excessive HDAC activation is critical for neurodegeneration in the rd1 mouse
- 2010
-
Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 1
-
Tidskriftsartikel (refereegranskat)abstract
- Inherited retinal degenerations, collectively termed retinitis pigmentosa (RP), constitute one of the leading causes of blindness in the developed world. RP is at present untreatable and the underlying neurodegenerative mechanisms are unknown, even though the genetic causes are often established. Acetylation and deacetylation of histones, carried out by histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively, affects cellular division, differentiation, death and survival. We found acetylation of histones and probably other proteins to be dramatically reduced in degenerating photoreceptors in the rd1 human homologous mouse model for RP. Using a custom developed in situ HDAC activity assay, we show that overactivation of HDAC classes I/II temporally precedes photoreceptor degeneration. Moreover, pharmacological inhibition of HDACs I/II activity in rd1 organotypic retinal explants decreased activity of poly-ADP-ribose-polymerase and strongly reduced photoreceptor cell death. These findings highlight the importance of protein acetylation for photoreceptor cell death and survival and propose certain HDAC classes as novel targets for the pharmacological intervention in RP. Cell Death and Disease (2010) 1, e24; doi:10.1038/cddis.2010.4; published online 11 February 2010
|
|
