@article {804, title = {The mechanistic functional landscape of retinitis pigmentosa: a machine learning-driven approach to therapeutic target discovery.}, journal = {J Transl Med}, volume = {22}, year = {2024}, month = {2024 Feb 06}, pages = {139}, abstract = {

BACKGROUND: Retinitis pigmentosa is the prevailing genetic cause of blindness in developed nations with no effective treatments. In the pursuit of unraveling the intricate dynamics underlying this complex disease, mechanistic models emerge as a tool of proven efficiency rooted in systems biology, to elucidate the interplay between RP genes and their mechanisms. The integration of mechanistic models and drug-target interactions under the umbrella of machine learning methodologies provides a multifaceted approach that can boost the discovery of novel therapeutic targets, facilitating further drug repurposing in RP.

METHODS: By mapping Retinitis Pigmentosa-related genes (obtained from Orphanet, OMIM and HPO databases) onto KEGG signaling pathways, a collection of signaling functional circuits encompassing Retinitis Pigmentosa molecular mechanisms was defined. Next, a mechanistic model of the so-defined disease map, where the effects of interventions can be simulated, was built. Then, an explainable multi-output random forest regressor was trained using normal tissue transcriptomic data to learn causal connections between targets of approved drugs from DrugBank and the functional circuits of the mechanistic disease map. Selected target genes involvement were validated on rd10 mice, a murine model of Retinitis Pigmentosa.

RESULTS: A mechanistic functional map of Retinitis Pigmentosa was constructed resulting in 226 functional circuits belonging to 40 KEGG signaling pathways. The method predicted 109 targets of approved drugs in use with a potential effect over circuits corresponding to nine hallmarks identified. Five of those targets were selected and experimentally validated in rd10 mice: Gabre, Gabra1 (GABARĪ±1 protein), Slc12a5 (KCC2 protein), Grin1 (NR1 protein) and Glr2a. As a result, we provide a resource to evaluate the potential impact of drug target genes in Retinitis Pigmentosa.

CONCLUSIONS: The possibility of building actionable disease models in combination with machine learning algorithms to learn causal drug-disease interactions opens new avenues for boosting drug discovery. Such mechanistically-based hypotheses can guide and accelerate the experimental validations prioritizing drug target candidates. In this work, a mechanistic model describing the functional disease map of Retinitis Pigmentosa was developed, identifying five promising therapeutic candidates targeted by approved drug. Further experimental validation will demonstrate the efficiency of this approach for a systematic application to other rare diseases.

}, keywords = {Animals, Mice, Retinitis pigmentosa, Signal Transduction}, issn = {1479-5876}, doi = {10.1186/s12967-024-04911-7}, author = {Esteban-Medina, Marina and Loucera, Carlos and Rian, Kinza and Velasco, Sheyla and Olivares-Gonz{\'a}lez, Lorena and Rodrigo, Regina and Dopazo, Joaquin and Pe{\~n}a-Chilet, Maria} } @article {806, title = {Primary Ciliary Dyskinesia and Retinitis Pigmentosa: Novel Variant and Possible Modifier Gene.}, journal = {Cells}, volume = {13}, year = {2024}, month = {2024 Mar 16}, abstract = {

We report a novel missense variant co-segregated with a familial X-linked retinitis pigmentosa (XLRP) case. The brothers were hemizygous for this variant, but only the proband presented with primary ciliary dyskinesia (PCD). Thus, we aimed to elucidate the role of the variant and other modifier genes in the phenotypic variability observed in the family and its impact on motile cilia. The pathogenicity of the variant on the RPGR protein was evaluated by in vitro studies transiently transfecting the mutated gene, and immunofluorescence analysis on nasal brushing samples. Whole-exome sequencing was conducted to identify potential modifier variants. In vitro studies showed that the mutated RPGR protein could not localise to the cilium and impaired cilium formation. Accordingly, RPGR was abnormally distributed in the siblings{\textquoteright} nasal brushing samples. In addition, a missense variant in was identified. The concurrent variant influenced ciliary mislocalisation of the protein. We provide a comprehensive characterisation of motile cilia in this XLRP family, with only the proband presenting PCD symptoms. The variant{\textquoteright}s pathogenicity was confirmed, although it alone does not explain the respiratory symptoms. Finally, the gene may be a potential modifier for respiratory symptoms in patients with mutations.

}, keywords = {Ciliary Motility Disorders, Eye Proteins, Genes, Modifier, Humans, Male, mutation, Retinitis pigmentosa}, issn = {2073-4409}, doi = {10.3390/cells13060524}, author = {Baz-Red{\'o}n, Noelia and S{\'a}nchez-Bellver, Laura and Fern{\'a}ndez-Cancio, M{\'o}nica and Rovira-Amigo, Sandra and Burgoyne, Thomas and Ranjit, Rai and Aquino, Virginia and Toro-Barrios, Noem{\'\i} and Carmona, Rosario and Polverino, Eva and Cols, Maria and Moreno-Gald{\'o}, Antonio and Camats-Tarruella, N{\'u}ria and Marfany, Gemma} } @article {437, title = {Identification of the Photoreceptor Transcriptional Co-Repressor SAMD11 as Novel Cause of Autosomal Recessive Retinitis Pigmentosa.}, journal = {Sci Rep}, volume = {6}, year = {2016}, month = {2016 Oct 13}, pages = {35370}, abstract = {

Retinitis pigmentosa (RP), the most frequent form of inherited retinal dystrophy is characterized by progressive photoreceptor degeneration. Many genes have been implicated in RP development, but several others remain to be identified. Using a combination of homozygosity mapping, whole-exome and targeted next-generation sequencing, we found a novel homozygous nonsense mutation in SAMD11 in five individuals diagnosed with adult-onset RP from two unrelated consanguineous Spanish families. SAMD11 is ortholog to the mouse major retinal SAM domain (mr-s) protein that is implicated in CRX-mediated transcriptional regulation in the retina. Accordingly, protein-protein network analysis revealed a significant interaction of SAMD11 with CRX. Immunoblotting analysis confirmed strong expression of SAMD11 in human retina. Immunolocalization studies revealed SAMD11 was detected in the three nuclear layers of the human retina and interestingly differential expression between cone and rod photoreceptors was observed. Our study strongly implicates SAMD11 as novel cause of RP playing an important role in the pathogenesis of human degeneration of photoreceptors.

}, keywords = {Aged, Animals, Co-Repressor Proteins, Codon, Nonsense, Cohort Studies, Comparative Genomic Hybridization, Consanguinity, DNA Mutational Analysis, Exome, Eye Proteins, Female, Gene Expression Regulation, Genes, Recessive, Homeodomain Proteins, Homozygote, Humans, Male, Mice, Middle Aged, Polymorphism, Single Nucleotide, Protein Interaction Mapping, Retina, Retinal Dystrophies, Retinal Rod Photoreceptor Cells, Retinitis pigmentosa, Spain, Trans-Activators, Transcription Factors}, issn = {2045-2322}, doi = {10.1038/srep35370}, author = {Corton, M and Avila-Fern{\'a}ndez, A and Campello, L and S{\'a}nchez, M and Benavides, B and L{\'o}pez-Molina, M I and Fern{\'a}ndez-S{\'a}nchez, L and S{\'a}nchez-Alcudia, R and da Silva, L R J and Reyes, N and Mart{\'\i}n-Garrido, E and Zurita, O and Fern{\'a}ndez-San Jos{\'e}, P and P{\'e}rez-Carro, R and Garc{\'\i}a-Garc{\'\i}a, F and Dopazo, J and Garc{\'\i}a-Sandoval, B and Cuenca, N and Ayuso, C} } @article {467, title = {Re-evaluation casts doubt on the pathogenicity of homozygous USH2A p.C759F.}, journal = {Am J Med Genet A}, volume = {167}, year = {2015}, month = {2015 Jul}, pages = {1597-600}, abstract = {

Mutations in USH2A are a common cause of Retinitis Pigmentosa (RP). Among the most frequently reported USH2A variants, c.2276G>T (p.C759F) has been found in both affected and healthy individuals. The pathogenicity of this variant remains controversial since it was detected in homozygosity in two healthy siblings of a Spanish family (S23), eleven years ago. The fact that these individuals remain asymptomatic today, prompted us to study the presence of other pathogenic variants in this family using targeted resequencing of 26 retinal genes in one of the affected individuals. This approach allowed us to identify one novel pathogenic homozygous mutation in exon 13 of PDE6B (c.1678C>T; p.R560C). This variant cosegregated with the disease and was absent in 200 control individuals. Remarkably, the identified variant in PDE6B corresponds to the mutation responsible of the retinal degeneration in the naturally occurring rd10 mutant mice. To our knowledge, this is the first report of the identification of the rd10 mice mutation in a RP family. These findings, together with a review of the literature, support the hypothesis that homozygous p.C759F mutations are not pathogenic and led us to exclude the implication of p.C759F in the RP of family S23. Our results indicate the need of re-evaluating all families genetically diagnosed with this mutation.

}, keywords = {Base Sequence, Cyclic Nucleotide Phosphodiesterases, Type 6, Extracellular Matrix Proteins, Gene Library, Humans, Molecular Sequence Data, Mutation, Missense, Pedigree, Retinitis pigmentosa, Sequence Analysis, DNA, Spain}, issn = {1552-4833}, doi = {10.1002/ajmg.a.37003}, author = {Pozo, Mar{\'\i}a Gonz{\'a}lez-Del and Bravo-Gil, Nereida and M{\'e}ndez-Vidal, Cristina and Montero-de-Espinosa, Ignacio and Mill{\'a}n, Jos{\'e} M and Dopazo, Joaquin and Borrego, Salud and Anti{\v n}olo, Guillermo} } @article {463, title = {Whole-exome sequencing reveals ZNF408 as a new gene associated with autosomal recessive retinitis pigmentosa with vitreal alterations.}, journal = {Hum Mol Genet}, volume = {24}, year = {2015}, month = {2015 Jul 15}, pages = {4037-48}, abstract = {

Retinitis pigmentosa (RP) is a group of progressive inherited retinal dystrophies that cause visual impairment as a result of photoreceptor cell death. RP is heterogeneous, both clinically and genetically making difficult to establish precise genotype-phenotype correlations. In a Spanish family with autosomal recessive RP (arRP), homozygosity mapping and whole-exome sequencing led to the identification of a homozygous mutation (c.358_359delGT; p.Ala122Leufs*2) in the ZNF408 gene. A screening performed in 217 additional unrelated families revealed another homozygous mutation (c.1621C>T; p.Arg541Cys) in an isolated RP case. ZNF408 encodes a transcription factor that harbors 10 predicted C2H2-type fingers thought to be implicated in DNA binding. To elucidate the ZNF408 role in the retina and the pathogenesis of these mutations we have performed different functional studies. By immunohistochemical analysis in healthy human retina, we identified that ZNF408 is expressed in both cone and rod photoreceptors, in a specific type of amacrine and ganglion cells, and in retinal blood vessels. ZNF408 revealed a cytoplasmic localization and a nuclear distribution in areas corresponding with the euchromatin fraction. Immunolocalization studies showed a partial mislocalization of the p.Arg541Cys mutant protein retaining part of the WT protein in the cytoplasm. Our study demonstrates that ZNF408, previously associated with Familial Exudative Vitreoretinopathy (FEVR), is a new gene causing arRP with vitreous condensations supporting the evidence that this protein plays additional functions into the human retina.

}, keywords = {Amino Acid Sequence, Animals, Chlorocebus aethiops, Chromosome Mapping, COS Cells, DNA-Binding Proteins, Exome, Genome-Wide Association Study, High-Throughput Nucleotide Sequencing, Homozygote, Humans, Molecular Sequence Data, Mutant Proteins, Pedigree, Retina, Retinal Cone Photoreceptor Cells, Retinal Rod Photoreceptor Cells, Retinitis pigmentosa, Transcription Factors}, issn = {1460-2083}, doi = {10.1093/hmg/ddv140}, author = {Avila-Fernandez, Almudena and Perez-Carro, Raquel and Corton, Marta and Lopez-Molina, Maria Isabel and Campello, Laura and Garanto, Alejandro and Fernandez-Sanchez, Laura and Duijkers, Lonneke and Lopez-Martinez, Miguel Angel and Riveiro-Alvarez, Rosa and da Silva, Luciana Rodrigues Jacy and Sanchez-Alcudia, Roc{\'\i}o and Martin-Garrido, Esther and Reyes, Noelia and Garcia-Garcia, Francisco and Dopazo, Joaquin and Garcia-Sandoval, Blanca and Collin, Rob W J and Cuenca, Nicolas and Ayuso, Carmen} } @article {490, title = {Novel RP1 mutations and a recurrent BBS1 variant explain the co-existence of two distinct retinal phenotypes in the same pedigree.}, journal = {BMC Genet}, volume = {15}, year = {2014}, month = {2014 Dec 14}, pages = {143}, abstract = {

BACKGROUND: Molecular diagnosis of Inherited Retinal Dystrophies (IRD) has long been challenging due to the extensive clinical and genetic heterogeneity present in this group of disorders. Here, we describe the clinical application of an integrated next-generation sequencing approach to determine the underlying genetic defects in a Spanish family with a provisional clinical diagnosis of autosomal recessive Retinitis Pigmentosa (arRP).

RESULTS: Exome sequencing of the index patient resulted in the identification of the homozygous BBS1 p.M390R mutation. Sanger sequencing of additional members of the family showed lack of co-segregation of the p.M390R variant in some individuals. Clinical reanalysis indicated co-ocurrence of two different phenotypes in the same family: Bardet-Biedl syndrome in the individual harboring the BBS1 mutation and non-syndromic arRP in extended family members. To identify possible causative mutations underlying arRP, we conducted disease-targeted gene sequencing using a panel of 26 IRD genes. The in-house custom panel was validated using 18 DNA samples known to harbor mutations in relevant genes. All variants were redetected, indicating a high mutation detection rate. This approach allowed the identification of two novel heterozygous null mutations in RP1 (c.4582_4585delATCA; p.I1528Vfs*10 and c.5962dupA; p.I1988Nfs*3) which co-segregated with the disease in arRP patients. Additionally, a mutational screening in 96 patients of our cohort with genetically unresolved IRD revealed the presence of the c.5962dupA mutation in one unrelated family.

CONCLUSIONS: The combination of molecular findings for RP1 and BBS1 genes through exome and gene panel sequencing enabled us to explain the co-existence of two different retinal phenotypes in a family. The identification of two novel variants in RP1 suggests that the use of panels containing the prevalent genes of a particular population, together with an optimized data analysis pipeline, is an efficient and cost-effective approach that can be reliably implemented into the routine diagnostic process of diverse inherited retinal disorders. Moreover, the identification of these novel variants in two unrelated families supports the relatively high prevalence of RP1 mutations in Spanish population and the role of private mutations for commonly mutated genes, while extending the mutational spectrum of RP1.

}, keywords = {Bardet-Biedl Syndrome, Base Sequence, Case-Control Studies, DNA Mutational Analysis, Eye Proteins, Genes, Recessive, Genetic Association Studies, Humans, Microsatellite Repeats, Microtubule-Associated Proteins, Mutation, Missense, Pedigree, Phenotype, Retina, Retinitis pigmentosa}, issn = {1471-2156}, doi = {10.1186/s12863-014-0143-2}, author = {M{\'e}ndez-Vidal, Cristina and Bravo-Gil, Nereida and Gonz{\'a}lez-del Pozo, Mar{\'\i}a and Vela-Boza, Alicia and Dopazo, Joaquin and Borrego, Salud and Anti{\v n}olo, Guillermo} } @article {536, title = {Mutation screening of multiple genes in Spanish patients with autosomal recessive retinitis pigmentosa by targeted resequencing.}, journal = {PLoS One}, volume = {6}, year = {2011}, month = {2011}, pages = {e27894}, abstract = {

Retinitis Pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterised ultimately by the loss of photoreceptor cells. RP is the leading cause of visual loss in individuals younger than 60 years, with a prevalence of about 1 in 4000. The molecular genetic diagnosis of autosomal recessive RP (arRP) is challenging due to the large genetic and clinical heterogeneity. Traditional methods for sequencing arRP genes are often laborious and not easily available and a screening technique that enables the rapid detection of the genetic cause would be very helpful in the clinical practice. The goal of this study was to develop and apply microarray-based resequencing technology capable of detecting both known and novel mutations on a single high-throughput platform. Hence, the coding regions and exon/intron boundaries of 16 arRP genes were resequenced using microarrays in 102 Spanish patients with clinical diagnosis of arRP. All the detected variations were confirmed by direct sequencing and potential pathogenicity was assessed by functional predictions and frequency in controls. For validation purposes 4 positive controls for variants consisting of previously identified changes were hybridized on the array. As a result of the screening, we detected 44 variants, of which 15 are very likely pathogenic detected in 14 arRP families (14\%). Finally, the design of this array can easily be transformed in an equivalent diagnostic system based on targeted enrichment followed by next generation sequencing.

}, keywords = {Alleles, DNA Mutational Analysis, Exons, Genetic Variation, Genome, Hispanic or Latino, Humans, Introns, Language, mutation, Mutation, Missense, Oligonucleotide Array Sequence Analysis, Polymerase Chain Reaction, Reproducibility of Results, Retinitis pigmentosa, United States}, issn = {1932-6203}, doi = {10.1371/journal.pone.0027894}, author = {Gonz{\'a}lez-del Pozo, Mar{\'\i}a and Borrego, Salud and Barrag{\'a}n, Isabel and Pieras, Juan I and Santoyo, Javier and Matamala, Nerea and Naranjo, Bel{\'e}n and Dopazo, Joaquin and Anti{\v n}olo, Guillermo} } @article {575, title = {Mutation spectrum of EYS in Spanish patients with autosomal recessive retinitis pigmentosa.}, journal = {Hum Mutat}, volume = {31}, year = {2010}, month = {2010 Nov}, pages = {E1772-800}, abstract = {

Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterised ultimately by the loss of photoreceptor cells. We have recently identified a new gene(EYS) encoding an ortholog of Drosophila space maker (spam) as a commonly mutated gene in autosomal recessive RP. In the present study, we report the identification of 73 sequence variations in EYS, of which 28 are novel. Of these, 42.9\% (12/28) are very likely pathogenic, 17.9\% (5/28)are possibly pathogenic, whereas 39.3\% (11/28) are SNPs. In addition, we have detected 3 pathogenic changes previously reported in other populations. We are also presenting the characterisation of EYS homologues in different species, and a detailed analysis of the EYS domains, with the identification of an interesting novel feature: a putative coiled-coil domain.Majority of the mutations in the arRP patients have been found within the domain structures of EYS. The minimum observed prevalence of distinct EYS mutations in our group of patients is of 15.9\% (15/94), confirming a major involvement of EYS in the pathogenesis of arRP in the Spanish population. Along with the detection of three recurrent mutations in Caucasian population, our hypothesis of EYS being the first prevalent gene in arRP has been reinforced in the present study.

}, keywords = {Amino Acid Sequence, Animals, Case-Control Studies, DNA Mutational Analysis, Drosophila Proteins, Evolution, Molecular, Eye Proteins, Female, Genes, Recessive, Genetic Variation, Humans, Male, Molecular Sequence Data, mutation, Pedigree, Polymorphism, Single Nucleotide, Protein Structure, Tertiary, Retinitis pigmentosa, Spain, Structural Homology, Protein}, issn = {1098-1004}, doi = {10.1002/humu.21334}, author = {Barrag{\'a}n, Isabel and Borrego, Salud and Pieras, Juan Ignacio and Gonz{\'a}lez-del Pozo, Mar{\'\i}a and Santoyo, Javier and Ayuso, Carmen and Baiget, Montserrat and Mill{\'a}n, Jos{\'e} M and Mena, Marcela and Abd El-Aziz, Mai M and Audo, Isabelle and Zeitz, Christina and Littink, Karin W and Dopazo, Joaquin and Bhattacharya, Shomi S and Anti{\v n}olo, Guillermo} }