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Esteve-Garcia A, Cobos E, Sau C, Padró-Miquel A, Català-Mora J, Barberán-Martínez P, Millán JM, García-García G, Aguilera C. Deciphering complexity: TULP1 variants linked to an atypical retinal dystrophy phenotype. Front Genet 2024; 15:1352063. [PMID: 38450199 PMCID: PMC10915255 DOI: 10.3389/fgene.2024.1352063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/29/2024] [Indexed: 03/08/2024] Open
Abstract
Introduction: TULP1 exemplifies the remarkable clinical and genetic heterogeneity observed in inherited retinal dystrophies. Our research describes the clinical and molecular characteristics of a patient manifesting an atypical retinal dystrophy pattern, marked by the identification of both a previously unreported and a rarely encountered TULP1 variant. Methods: Whole-exome sequencing was performed to identify potential causative variants. The pathogenicity of the identified TULP1 variants was evaluated through in silico predictors and a minigene splice assay, specifically designed to assess the effect of the unreported TULP1 variant. Results: We identified two TULP1 gene variants in a patient exhibiting unusual and symmetrical alterations in both retinas, characterized by an increase in autofluorescence along the distribution of retinal vessels. These variants included a known rare missense variant, c.1376T>C, and a novel splice site variant, c.822G>T. For the latter variant (c.822G>T), we conducted a minigene splice assay that demonstrated the incorporation of a premature stop codon. This finding suggests a likely activation of the nonsense-mediated mRNA decay mechanism, ultimately resulting in the absence of protein production from this allele. Segregation analysis confirmed that these variants were in trans. Discussion: Our data support that individuals with biallelic TULP1 variants may present with a unique pattern of macular degeneration and periarteriolar vascular pigmentation. This study highlights the importance of further clinical and molecular characterization of TULP1 variants to elucidate genotype-phenotype correlations in the context of inherited retinal dystrophies.
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Affiliation(s)
- Anna Esteve-Garcia
- Department of Clinical Genetics, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Estefania Cobos
- Department of Ophthalmology, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Cristina Sau
- Department of Clinical Genetics, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Ariadna Padró-Miquel
- Genetics Laboratory, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Jaume Català-Mora
- Department of Ophthalmology, SJD Barcelona Children’s Hospital, Barcelona, Spain
| | - Pilar Barberán-Martínez
- Molecular, Cellular, and Genomic Biomedicine Group, Valencia, Spain
- Joint Unit CIPF-IIS La Fe Molecular, Cellular and Genomic Biomedicine, Valencia, Spain
| | - José M. Millán
- Molecular, Cellular, and Genomic Biomedicine Group, Valencia, Spain
- Joint Unit CIPF-IIS La Fe Molecular, Cellular and Genomic Biomedicine, Valencia, Spain
- Center for Rare Diseases (CIBERER), Madrid, Spain
- University and Polytechnic La Fe Hospital of Valencia, Valencia, Spain
| | - Gema García-García
- Molecular, Cellular, and Genomic Biomedicine Group, Valencia, Spain
- Joint Unit CIPF-IIS La Fe Molecular, Cellular and Genomic Biomedicine, Valencia, Spain
- Center for Rare Diseases (CIBERER), Madrid, Spain
| | - Cinthia Aguilera
- Genetics Laboratory, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
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Spencer WJ. Extracellular vesicles highlight many cases of photoreceptor degeneration. Front Mol Neurosci 2023; 16:1182573. [PMID: 37273908 PMCID: PMC10233141 DOI: 10.3389/fnmol.2023.1182573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
The release of extracellular vesicles is observed across numerous cell types and serves a range of biological functions including intercellular communication and waste disposal. One cell type which stands out for its robust capacity to release extracellular vesicles is the vertebrate photoreceptor cell. For decades, the release of extracellular vesicles by photoreceptors has been documented in many different animal models of photoreceptor degeneration and, more recently, in wild type photoreceptors. Here, I review all studies describing extracellular vesicle release by photoreceptors and discuss the most unifying theme among them-a photoreceptor cell fully, or partially, diverts its light sensitive membrane material to extracellular vesicles when it has defects in the delivery or morphing of this material into the photoreceptor's highly organized light sensing organelle. Because photoreceptors generate an enormous amount of light sensitive membrane every day, the diversion of this material to extracellular vesicles can cause a massive accumulation of these membranes within the retina. Little is known about the uptake of photoreceptor derived extracellular vesicles, although in some cases the retinal pigment epithelial cells, microglia, Müller glia, and/or photoreceptor cells themselves have been shown to phagocytize them.
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Wang A, Wei Z, Yuan H, Zhu Y, Peng Y, Gao Z, Liu Y, Shen J, Xu H, Guan J, Yin S, Liu F, Li X. FKBP5 genetic variants are associated with respiratory- and sleep-related parameters in Chinese patients with obstructive sleep apnea. Front Neurosci 2023; 17:1170889. [PMID: 37274192 PMCID: PMC10233201 DOI: 10.3389/fnins.2023.1170889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/27/2023] [Indexed: 06/06/2023] Open
Abstract
Introduction Obstructive sleep apnea (OSA) has been associated with psychiatric disorders, especially depression and posttraumatic stress disorder (PTSD). FKBP5 genetic variants have been previously reported to confer the risk of depression and PTSD. This study aimed to investigate the association of single nucleotide polymorphisms (SNPs) in the FKBP5 gene with OSA and OSA-related quantitative traits. Methods Four SNPs within the FKBP5 gene (rs1360780, rs3800373, rs9296158, rs9470080) were genotyped in 5773 participants with anthropometric and polysomnography data. Linear regression and logistic regression analyses were performed to evaluate the relationship between FKBP5 SNPs and OSA-related traits. Binary logistic regression was used to assess the effect of SNPs on OSA susceptibility. Interacting genes of SNPs were assessed based on the 3DSNP database, and expression quantitative trait loci (eQTL) analysis for SNPs was adopted to examine the correlation of SNPs with gene expression. Gene expression analyses in human brains were performed with the aid of Brain Atlas. Results In moderate-to-severe OSA patients, all four SNPs were positively associated with AHIREM, and rs9296158 showed the strongest association (ß = 1.724, p = 0.001). Further stratified analyses showed that in men with moderate OSA, rs1360780, rs3800373 and rs9470080 were positively associated with wake time (p = 0.0267, p = 0.0254 and p = 0.0043, respectively). Rs1360780 and rs3800373 were 28 and 29.4%more likely to rate a higher ordered MAI category (OR (95% CI) = 1.280 (1.042 - 1.575), p = 0.019; OR (95% CI) = 1.294 (1.052 - 1.592), p = 0.015, respectively). Rs9296158 and rs9470080 increased the risk of low sleep efficiency by 25.7 and 28.1% (OR (95% CI) = 1.257 (1.003 - 1.575), p = 0.047; OR (95% CI) = 1.281 (1.026-1.6), p = 0.029, respectively). Integrated analysis of eQTL and gene expression patterns revealed that four SNPs may exert their effects by regulating FKBP5, TULP1, and ARMC12. Conclusion Single nucleotide polymorphisms in the FKBP5 gene were associated with sleep respiratory events in moderate-to-severe OSA patients during REM sleep and associated with sleep architecture variables in men with moderate OSA. FKBP5 variants may be a potential predisposing factor for sleep disorders, especially in REM sleep.
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Affiliation(s)
- Anzhao Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Zhicheng Wei
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Haolin Yuan
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Yaxin Zhu
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Yu Peng
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Zhenfei Gao
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Yuenan Liu
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Jinhong Shen
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Huajun Xu
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Jian Guan
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Shankai Yin
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Feng Liu
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Xinyi Li
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
- Otorhinolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
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Bodenbender JP, Marino V, Bethge L, Stingl K, Haack TB, Biskup S, Kohl S, Kühlewein L, Dell’Orco D, Weisschuh N. Biallelic Variants in TULP1 Are Associated with Heterogeneous Phenotypes of Retinal Dystrophy. Int J Mol Sci 2023; 24:ijms24032709. [PMID: 36769033 PMCID: PMC9916573 DOI: 10.3390/ijms24032709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Biallelic pathogenic variants in TULP1 are mostly associated with severe rod-driven inherited retinal degeneration. In this study, we analyzed clinical heterogeneity in 17 patients and characterized the underlying biallelic variants in TULP1. All patients underwent thorough ophthalmological examinations. Minigene assays and structural analyses were performed to assess the consequences of splice variants and missense variants. Three patients were diagnosed with Leber congenital amaurosis, nine with early onset retinitis pigmentosa, two with retinitis pigmentosa with an onset in adulthood, one with cone dystrophy, and two with cone-rod dystrophy. Seventeen different alleles were identified, namely eight missense variants, six nonsense variants, one in-frame deletion variant, and two splice site variants. For the latter two, minigene assays revealed aberrant transcripts containing frameshifts and premature termination codons. Structural analysis and molecular modeling suggested different degrees of structural destabilization for the missense variants. In conclusion, we report the largest cohort of patients with TULP1-associated IRD published to date. Most of the patients exhibited rod-driven disease, yet a fraction of the patients exhibited cone-driven disease. Our data support the hypothesis that TULP1 variants do not fold properly and thus trigger unfolded protein response, resulting in photoreceptor death.
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Affiliation(s)
- Jan-Philipp Bodenbender
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
- Correspondence: (J.-P.B.); (N.W.)
| | - Valerio Marino
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37124 Verona, Italy
| | - Leon Bethge
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Katarina Stingl
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Tobias B. Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany
- Centre for Rare Diseases, University of Tübingen, 72076 Tübingen, Germany
| | - Saskia Biskup
- Praxis für Humangenetik, 72076 Tübingen, Germany
- CeGaT GmbH, 72076 Tübingen, Germany
| | - Susanne Kohl
- Department for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Laura Kühlewein
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Daniele Dell’Orco
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37124 Verona, Italy
| | - Nicole Weisschuh
- Department for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Correspondence: (J.-P.B.); (N.W.)
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Tulp1 deficiency causes early-onset retinal degeneration through affecting ciliogenesis and activating ferroptosis in zebrafish. Cell Death Dis 2022; 13:962. [PMID: 36396940 PMCID: PMC9672332 DOI: 10.1038/s41419-022-05372-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/22/2022] [Accepted: 10/24/2022] [Indexed: 11/19/2022]
Abstract
Mutations in TUB-like protein 1 (TULP1) are associated with severe early-onset retinal degeneration in humans. However, the pathogenesis remains largely unknown. There are two homologous genes of TULP1 in zebrafish, namely tulp1a and tulp1b. Here, we generated the single knockout (tulp1a-/- and tulp1b-/-) and double knockout (tulp1-dKO) models in zebrafish. Knockout of tulp1a resulted in the mislocalization of UV cone opsins and the degeneration of UV cones specifically, while knockout of tulp1b resulted in mislocalization of rod opsins and rod-cone degeneration. In the tulp1-dKO zebrafish, mislocalization of opsins was present in all types of photoreceptors, and severe degeneration was observed at a very early age, mimicking the clinical manifestations of TULP1 patients. Photoreceptor cilium length was significantly reduced in the tulp1-dKO retinas. RNA-seq analysis showed that the expression of tektin2 (tekt2), a ciliary and flagellar microtubule structural component, was downregulated in the tulp1-dKO zebrafish. Dual-luciferase reporter assay suggested that Tulp1a and Tulp1b transcriptionally activate the promoter of tekt2. In addition, ferroptosis might be activated in the tulp1-dKO zebrafish, as suggested by the up-regulation of genes related to the ferroptosis pathway, the shrinkage of mitochondria, reduction or disappearance of mitochondria cristae, and the iron and lipid droplet deposition in the retina of tulp1-dKO zebrafish. In conclusion, our study establishes an appropriate zebrafish model for TULP1-associated retinal degeneration and proposes that loss of TULP1 causes defects in cilia structure and opsin trafficking through the downregulation of tekt2, which further increases the death of photoreceptors via ferroptosis. These findings offer insight into the pathogenesis and clinical treatment of early-onset retinal degeneration.
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