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Kiraly P, Gavrić AU, Reichel FF, Birtel J, Mautone L, Atiskova Y, Herrmann P, Jarc-Vidmar M, Hawlina M, Downes SM, Fischer MD. Peripapillary retinal nerve fibre layer thinning in patients with X-linked retinoschisis. BMJ Open Ophthalmol 2024; 9:e001832. [PMID: 39209741 PMCID: PMC11367349 DOI: 10.1136/bmjophth-2024-001832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Accepted: 07/31/2024] [Indexed: 09/04/2024] Open
Abstract
AIMS To assess peripapillary retinal nerve fibre layer (pRNFL) thickness in patients with X-linked retinoschisis (XLRS), as pRNFL thinning may limit functional improvements in gene therapy trials. METHODS This retrospective multicentre study included 49 eyes from 25 patients diagnosed with XLRS. Data collected with multimodal imaging at baseline and last follow-up (when available) included age, best-recorded visual acuity (BRVA), central retinal thickness, macular volume (MV), presence and location of peripheral retinoschisis and pRNFL thickness in the global (G), superotemporal (TS), superonasal (NS), inferotemporal (TI), inferonasal (NI), nasal (N) and temporal (T) sectors. Retinal sensitivity, assessed by microperimetry, was also recorded for seven patients at baseline. RESULTS pRNFL was thinner (below the fifth percentile) in at least one sector in 72% of right eyes and 79% of left eyes, with thinning across three or more sectors in 20% of right and 17% of left eyes. In 44% of cases, thinning occurred in the temporal sectors of both eyes, with no nasal sectoral thinning. Number of peripheral retinoschisis quadrants matched thinned pRNFL sectors. A strong positive correlation was found between MV and temporal pRNFL thickness (r=0.71, p<0.01), while weak negative correlation trends were noted with age (p=0.05) and BRVA (logMAR; p=0.12) related to temporal thickness of pRNFL sectors. CONCLUSION pRNFL thinning, predominantly sectoral and linked to macular or peripheral retinoschisis, occurs in about three-quarters of patients with XLRS, while diffuse thinning occurs in one-fifth. Temporal pRNFL thinning might occur only after the collapse of intraretinal cystoid cavities in the macula.
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Affiliation(s)
- Peter Kiraly
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - Ana Uršula Gavrić
- Department of Ophthalmology, University Eye Hospital in Ljubljana, Ljubljana, Slovenia
| | - Felix F Reichel
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- University Eye Hospital, University Hospital Tuebingen, Tuebingen, Germany
| | - Johannes Birtel
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Luca Mautone
- Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Yevgeniya Atiskova
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Martina Jarc-Vidmar
- Department of Ophthalmology, University Eye Hospital in Ljubljana, Ljubljana, Slovenia
| | - Marko Hawlina
- Department of Ophthalmology, University Eye Hospital in Ljubljana, Ljubljana, Slovenia
| | - Susan M Downes
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - M Dominik Fischer
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
- University Eye Hospital, University Hospital Tuebingen, Tuebingen, Germany
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Gehrke EJ, Pandey A, Thompson J, Bhattarai S, Gurung P, Hsu Y, Drack AV. Investigating the role of Caspase-1 in a mouse model of Juvenile X-linked Retinoschisis. Front Med (Lausanne) 2024; 11:1347599. [PMID: 38938378 PMCID: PMC11208328 DOI: 10.3389/fmed.2024.1347599] [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: 12/01/2023] [Accepted: 05/07/2024] [Indexed: 06/29/2024] Open
Abstract
Purpose Previous studies have reported Caspase-1 (Casp1) is upregulated in mouse models of Juvenile X-linked Retinoschisis (XLRS), however no functional role for Casp1 in disease progression has been identified. We performed electroretinogram (ERG) and standardized optical coherence tomography (OCT) in mice deficient in the Retinoschisin-1 (Rs1) and Casp1 and Caspase-11 (Casp11) genes (Rs1-KO;Casp1/11-/- ) to test the hypothesis that Casp1 may play a role in disease evolution and or severity of disease. Currently, no studies have ventured to investigate the longer-term effects of Casp1 on phenotypic severity and disease progression over time in XLRS, and specifically the effect on electroretinogram. Methods Rs1-KO;Casp1/11-/- mice were generated by breeding Rs1-KO mice with Casp1/11-/- mice. OCT imaging was analyzed at 2-, 4-, and 15-16 months of age. Outer nuclear layer (ONL) thickness and adapted standardized cyst severity score were measured and averaged from 4 locations 500 μm from the optic nerve. Adapted standardized cyst severity score was 1: absent cysts, 2: <30 μm, 3: 30-49 μm, 4: 50-69 μm, 5: 70-99 μm, 6: >99 μm. Electroretinograms (ERG) were recorded in dark-adapted and light-adapted conditions at 2 and 4 months. Results obtained from Rs1-KO and Rs1-KO;Casp1/11-/- eyes were compared with age matched WT control eyes at 2 months. Results Intraretinal schisis was not observed on OCT in WT eyes, while schisis was apparent in most Rs1-KO and Rs1-KO;Casp1/11-/- eyes at 2 and 4 months of age. There was no difference in the cyst severity score from 2 to 4 months of age, or ONL thickness from 2 to 16 months of age between Rs1-KO and Rs1-KO;Casp1/11-/- eyes. ERG amplitudes were similarly reduced in Rs1-KO and Rs1-KO;Casp1/11-/- compared to WT controls at 2 months of age, and there was no difference between Rs1-KO and Rs1-KO;Casp1/11-/- eyes at 2 or 4 months of age, suggesting no impact on the electrical function of photoreceptors over time in the absence of Casp1. Conclusion Although Casp1 has been reported to be significantly upregulated in Rs1-KO mice, our preliminary data suggest that removing Casp1/11 does not modulate photoreceptor electrical function or alter the trajectory of the retinal architecture over time.
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Affiliation(s)
- Ella J. Gehrke
- Department of Ophthalmology and Visual Sciences, IVR, University of Iowa, Iowa City, IA, United States
| | - Araniko Pandey
- Department of Ophthalmology and Visual Sciences, IVR, University of Iowa, Iowa City, IA, United States
| | - Jacob Thompson
- Department of Ophthalmology and Visual Sciences, IVR, University of Iowa, Iowa City, IA, United States
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA, United States
| | - Sajag Bhattarai
- Department of Ophthalmology and Visual Sciences, IVR, University of Iowa, Iowa City, IA, United States
| | - Prajwal Gurung
- Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
| | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, IVR, University of Iowa, Iowa City, IA, United States
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, IVR, University of Iowa, Iowa City, IA, United States
- Department of Pediatrics and Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA, United States
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van der Veen I, Heredero Berzal A, Koster C, ten Asbroek ALMA, Bergen AA, Boon CJF. The Road towards Gene Therapy for X-Linked Juvenile Retinoschisis: A Systematic Review of Preclinical Gene Therapy in Cell-Based and Rodent Models of XLRS. Int J Mol Sci 2024; 25:1267. [PMID: 38279267 PMCID: PMC10816913 DOI: 10.3390/ijms25021267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
X-linked juvenile retinoschisis (XLRS) is an early-onset progressive inherited retinopathy affecting males. It is characterized by abnormalities in the macula, with formation of cystoid retinal cavities, frequently accompanied by splitting of the retinal layers, impaired synaptic transmission of visual signals, and associated loss of visual acuity. XLRS is caused by loss-of-function mutations in the retinoschisin gene located on the X chromosome (RS1, MIM 30083). While proof-of-concept studies for gene augmentation therapy have been promising in in vitro and rodent models, clinical trials in XLRS patients have not been successful thus far. We performed a systematic literature investigation using search strings related to XLRS and gene therapy in in vivo and in vitro models. Three rounds of screening (title/abstract, full text and qualitative) were performed by two independent reviewers until consensus was reached. Characteristics related to study design and intervention were extracted from all studies. Results were divided into studies using (1) viral and (2) non-viral therapies. All in vivo rodent studies that used viral vectors were assessed for quality and risk of bias using the SYRCLE's risk-of-bias tool. Studies using alternative and non-viral delivery techniques, either in vivo or in vitro, were extracted and reviewed qualitatively, given the diverse and dispersed nature of the information. For in-depth analysis of in vivo studies using viral vectors, outcome data for optical coherence tomography (OCT), immunohistopathology and electroretinography (ERG) were extracted. Meta-analyses were performed on the effect of recombinant adeno-associated viral vector (AAV)-mediated gene augmentation therapies on a- and b-wave amplitude as well as the ratio between b- and a-wave amplitudes (b/a-ratio) extracted from ERG data. Subgroup analyses and meta-regression were performed for model, dose, age at injection, follow-up time point and delivery method. Between-study heterogeneity was assessed with a Chi-square test of homogeneity (I2). We identified 25 studies that target RS1 and met our search string. A total of 19 of these studies reported rodent viral methods in vivo. Six of the 25 studies used non-viral or alternative delivery methods, either in vitro or in vivo. Of these, five studies described non-viral methods and one study described an alternative delivery method. The 19 aforementioned in vivo studies were assessed for risk of bias and quality assessments and showed inconsistency in reporting. This resulted in an unclear risk of bias in most included studies. All 19 studies used AAVs to deliver intact human or murine RS1 in rodent models for XLRS. Meta-analyses of a-wave amplitude, b-wave amplitude, and b/a-ratio showed that, overall, AAV-mediated gene augmentation therapy significantly ameliorated the disease phenotype on these parameters. Subgroup analyses and meta-regression showed significant correlations between b-wave amplitude effect size and dose, although between-study heterogeneity was high. This systematic review reiterates the high potential for gene therapy in XLRS, while highlighting the importance of careful preclinical study design and reporting. The establishment of a systematic approach in these studies is essential to effectively translate this knowledge into novel and improved treatment alternatives.
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Affiliation(s)
- Isa van der Veen
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Andrea Heredero Berzal
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Céline Koster
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Anneloor L. M. A. ten Asbroek
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Arthur A. Bergen
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Camiel J. F. Boon
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Ophthalmology, Leiden University Medical Center, Leiden University, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
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Vijayasarathy C, Zeng Y, Marangoni D, Dong L, Pan ZH, Simpson EM, Fariss RN, Sieving PA. Targeted Expression of Retinoschisin by Retinal Bipolar Cells in XLRS Promotes Resolution of Retinoschisis Cysts Sans RS1 From Photoreceptors. Invest Ophthalmol Vis Sci 2022; 63:8. [PMID: 36227606 PMCID: PMC9583743 DOI: 10.1167/iovs.63.11.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 09/18/2022] [Indexed: 01/14/2023] Open
Abstract
Purpose Loss of retinoschisin (RS1) function underlies X-linked retinoschisis (XLRS) pathology. In the retina, both photoreceptor inner segments and bipolar cells express RS1. However, the loss of RS1 function causes schisis primarily in the inner retina. To understand these cell type-specific phenotypes, we decoupled RS1 effects in bipolar cells from that in photoreceptors. Methods Bipolar cell transgene RS1 expression was achieved using two inner retina-specific promoters: (1) a minimal promoter engineered from glutamate receptor, metabotropic glutamate receptor 6 gene (mini-mGluR6/ Grm6) and (2) MiniPromoter (Ple155). Adeno-associated virus vectors encoding RS1 gene under either the mini-mGluR6 or Ple-155 promoter were delivered to the XLRS mouse retina through intravitreal or subretinal injection on postnatal day 14. Retinal structure and function were assessed 5 weeks later: immunohistochemistry for morphological characterization, optical coherence tomography and electroretinography (ERG) for structural and functional evaluation. Results Immunohistochemical analysis of RS1expression showed that expression with the MiniPromoter (Ple155) was heavily enriched in bipolar cells. Despite variations in vector penetrance and gene transfer efficiency across the injected retinas, those retinal areas with robust bipolar cell RS1 expression showed tightly packed bipolar cells with fewer cavities and marked improvement in inner retinal structure and synaptic function as judged by optical coherence tomography and electroretinography, respectively. Conclusions These results demonstrate that RS1 gene expression primarily in bipolar cells of the XLRS mouse retina, independent of photoreceptor expression, can ameliorate retinoschisis structural pathology and provide further evidence of RS1 role in cell adhesion.
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Affiliation(s)
- Camasamudram Vijayasarathy
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
| | - Yong Zeng
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
| | - Dario Marangoni
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
| | - Lijin Dong
- Genetic Engineering Facility, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Zhuo-Hua Pan
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics at BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert N. Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Paul A. Sieving
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
- Center for Ocular Regenerative Therapy, Department of Ophthalmology, University of California Davis, United States
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Schmid V, Wurzel A, Wetzel CH, Plössl K, Bruckmann A, Luckner P, Weber BHF, Friedrich U. Retinoschisin and novel Na/K-ATPase interaction partners Kv2.1 and Kv8.2 define a growing protein complex at the inner segments of mammalian photoreceptors. Cell Mol Life Sci 2022; 79:448. [PMID: 35876901 PMCID: PMC9314279 DOI: 10.1007/s00018-022-04409-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/05/2022] [Accepted: 05/30/2022] [Indexed: 11/28/2022]
Abstract
The RS1 gene on Xp 22.13 encodes retinoschisin which is known to directly interact with the retinal Na/K-ATPase at the photoreceptor inner segments. Pathologic mutations in RS1 cause X-linked juvenile retinoschisis (XLRS), a hereditary retinal dystrophy in young males. To further delineate the retinoschisin-Na/K-ATPase complex, co-immunoprecipitation was performed with porcine and murine retinal lysates targeting the ATP1A3 subunit. This identified the voltage-gated potassium (Kv) channel subunits Kv2.1 and Kv8.2 as direct interaction partners of the retinal Na/K-ATPase. Colocalization of the individual components of the complex was demonstrated at the membrane of photoreceptor inner segments. We further show that retinoschisin-deficiency, a frequent consequence of molecular pathology in XLRS, causes mislocalization of the macromolecular complex during postnatal retinal development with a simultaneous reduction of Kv2.1 and Kv8.2 protein expression, while the level of retinal Na/K-ATPase expression remains unaffected. Patch-clamp analysis revealed no effect of retinoschisin-deficiency on Kv channel mediated potassium ion currents in vitro. Together, our data suggest that Kv2.1 and Kv8.2 together with retinoschisin and the retinal Na/K-ATPase are integral parts of a macromolecular complex at the photoreceptor inner segments. Defective compartmentalization of this complex due to retinoschisin-deficiency may be a crucial step in initial XLRS pathogenesis.
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Affiliation(s)
- Verena Schmid
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Alexander Wurzel
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Christian H Wetzel
- Department of Psychiatry and Psychotherapy, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Karolina Plössl
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Astrid Bruckmann
- Institute of Biochemistry, Genetics and Microbiology, Protein Mass Spectrometry Group, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Patricia Luckner
- Institute of Biochemistry, Genetics and Microbiology, Protein Mass Spectrometry Group, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
- Institute of Clinical Human Genetics, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
| | - Ulrike Friedrich
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
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Hahn LC, van Schooneveld MJ, Wesseling NL, Florijn RJ, Ten Brink JB, Lissenberg-Witte BI, Strubbe I, Meester-Smoor MA, Thiadens AA, Diederen RM, van Cauwenbergh C, de Zaeytijd J, Walraedt S, de Baere E, Klaver CCW, Ossewaarde-van Norel J, Ingeborgh van den Born L, Hoyng CB, van Genderen MM, Sieving PA, Leroy BP, Bergen AA, Boon CJF. X-Linked Retinoschisis: Novel Clinical Observations and Genetic Spectrum in 340 Patients. Ophthalmology 2021; 129:191-202. [PMID: 34624300 DOI: 10.1016/j.ophtha.2021.09.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To describe the natural course, phenotype, and genotype of patients with X-linked retinoschisis (XLRS). DESIGN Retrospective cohort study. PARTICIPANTS Three hundred forty patients with XLRS from 178 presumably unrelated families. METHODS This multicenter, retrospective cohort study reviewed medical records of patients with XLRS for medical history, symptoms, visual acuity (VA), ophthalmoscopy, full-field electroretinography, and retinal imaging (fundus photography, spectral-domain [SD] OCT, fundus autofluorescence). MAIN OUTCOME MEASURES Age at onset, age at diagnosis, severity of visual impairment, annual visual decline, and electroretinography and imaging findings. RESULTS Three hundred forty patients were included with a mean follow-up time of 13.2 years (range, 0.1-50.1 years). The median ages to reach mild visual impairment and low vision were 12 and 25 years, respectively. Severe visual impairment and blindness were observed predominantly in patients older than 40 years, with a predicted prevalence of 35% and 25%, respectively, at 60 years of age. The VA increased slightly during the first 2 decades of life and subsequently transitioned into an average annual decline of 0.44% (P < 0.001). No significant difference was found in decline of VA between variants that were predicted to be severe and mild (P = 0.239). The integrity of the ellipsoid zone (EZ) as well as the photoreceptor outer segment (PROS) length in the fovea on SD OCT correlated significantly with VA (Spearman's ρ = -0.759 [P < 0.001] and -0.592 [P = 0.012], respectively). Fifty-three different RS1 variants were found. The most common variants were the founder variant c.214G→A (p.(Glu72Lys)) (101 patients [38.7%]) and a deletion of exon 3 (38 patients [14.6%]). CONCLUSIONS Large variabilities in phenotype and natural course of XLRS were seen in this study. In most patients, XLRS showed a slow deterioration starting in the second decade of life, suggesting an optimal window of opportunity for treatment within the first 3 decades of life. The integrity of EZ as well as the PROS length on SD OCT may be important in choosing optimal candidates for treatment and as potential structural end points in future therapeutic studies. No clear genotype-phenotype correlation was found.
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Affiliation(s)
- Leo C Hahn
- Department of Ophthalmology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Mary J van Schooneveld
- Department of Ophthalmology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Bartiméus, Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | - Nieneke L Wesseling
- Department of Ophthalmology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Ralph J Florijn
- Department of Clinical Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Jacoline B Ten Brink
- Department of Clinical Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Birgit I Lissenberg-Witte
- Department of Epidemiology and Biostatistics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Ine Strubbe
- Department of Ophthalmology, University Hospital Ghent, Ghent University & Ghent University, Ghent, Belgium
| | | | - Alberta A Thiadens
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Roselie M Diederen
- Department of Ophthalmology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Caroline van Cauwenbergh
- Department of Ophthalmology, University Hospital Ghent, Ghent University & Ghent University, Ghent, Belgium; Center for Medical Genetics Ghent, Ghent University Hospital & Ghent University, Ghent, Belgium
| | - Julie de Zaeytijd
- Department of Ophthalmology, University Hospital Ghent, Ghent University & Ghent University, Ghent, Belgium
| | - Sophie Walraedt
- Department of Ophthalmology, University Hospital Ghent, Ghent University & Ghent University, Ghent, Belgium
| | - Elfride de Baere
- Department of Ophthalmology, University Hospital Ghent, Ghent University & Ghent University, Ghent, Belgium; Center for Medical Genetics Ghent, Ghent University Hospital & Ghent University, Ghent, Belgium
| | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands; Institute of Molecular and Clinical Ophthalmology, University Hospital Basel, University of Basel, Basel, Switzerland
| | | | | | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maria M van Genderen
- Bartiméus, Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands; Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul A Sieving
- Department of Ophthalmology, School of Medicine, University of California at Davis, Sacramento, California
| | - Bart P Leroy
- Department of Ophthalmology, University Hospital Ghent, Ghent University & Ghent University, Ghent, Belgium; Division of Ophthalmology & CCMT, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Arthur A Bergen
- Department of Clinical Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; The Netherlands Institute for Neuroscience (NIN-KNAW), Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.
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Vijaysarathy C, Babu Sardar Pasha SP, Sieving PA. Of men and mice: Human X-linked retinoschisis and fidelity in mouse modeling. Prog Retin Eye Res 2021; 87:100999. [PMID: 34390869 DOI: 10.1016/j.preteyeres.2021.100999] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023]
Abstract
X-linked Retinoschisis (XLRS) is an early-onset transretinal dystrophy, often with a prominent macular component, that affects males and generally spares heterozygous females because of X-linked recessive inheritance. It results from loss-of-function RS1 gene mutations on the X-chromosome. XLRS causes bilateral reduced acuities from young age, and on clinical exam and by ocular coherence tomography (OCT) the neurosensory retina shows foveo-macular cystic schisis cavities in the outer plexiform (OPL) and inner nuclear layers (INL). XLRS manifests between infancy and school-age with variable phenotypic presentation and without reliable genotype-phenotype correlations. INL disorganization disrupts synaptic signal transmission from photoreceptors to ON-bipolar cells, and this reduces the electroretinogram (ERG) bipolar b-wave disproportionately to photoreceptor a-wave changes. RS1 gene expression is localized mainly to photoreceptors and INL bipolar neurons, and RS1 protein is thought to play a critical cell adhesion role during normal retinal development and later for maintenance of retinal structure. Several independent XLRS mouse models with mutant RS1 were created that recapitulate features of human XLRS disease, with OPL-INL schisis cavities, early onset and variable phenotype across mutant models, and reduced ERG b-wave to a-wave amplitude ratio. The faithful phenotype of the XLRS mouse has assisted in delineating the disease pathophysiology. Delivery to XLRS mouse retina of an AAV8-RS1 construct under control of the RS1 promoter restores the retinal structure and synaptic function (with increase of b-wave amplitude). It also ameliorates the schisis-induced inflammatory microglia phenotype toward a state of immune quiescence. The results imply that XLRS gene therapy could yield therapeutic benefit to preserve morphological and functional retina particularly when intervention is conducted at earlier ages before retinal degeneration becomes irreversible. A phase I/IIa single-center, open-label, three-dose-escalation clinical trial reported a suitable safety and tolerability profile of intravitreally administered AAV8-RS1 gene replacement therapy for XLRS participants. Dose-related ocular inflammation occurred after dosing, but this resolved with topical and oral corticosteroids. Systemic antibodies against AAV8 increased in dose-dependent fashion, but no antibodies were observed against the RS1 protein. Retinal cavities closed transiently in one participant. Technological innovations in methods of gene delivery and strategies to further reduce immune responses are expected to enhance the therapeutic efficacy of the vector and ultimate success of a gene therapy approach.
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Affiliation(s)
| | | | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA; Department of Ophthalmology, University of California Davis, 95817, USA.
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Vijayasarathy C, Zeng Y, Brooks MJ, Fariss RN, Sieving PA. Genetic Rescue of X-Linked Retinoschisis Mouse ( Rs1-/y) Retina Induces Quiescence of the Retinal Microglial Inflammatory State Following AAV8- RS1 Gene Transfer and Identifies Gene Networks Underlying Retinal Recovery. Hum Gene Ther 2020; 32:667-681. [PMID: 33019822 PMCID: PMC8312029 DOI: 10.1089/hum.2020.213] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To understand RS1 gene interaction networks in the X-linked retinoschisis (XLRS) mouse retina (Rs1-/y), we analyzed the transcriptome by RNA sequencing before and after in vivo expression of exogenous retinoschisin (RS1) gene delivered by AAV8. RS1 is a secreted cell adhesion protein that is critical for maintaining structural lamination and synaptic integrity of the neural retina. RS1 loss-of-function mutations cause XLRS disease in young boys and men, with splitting ("schisis") of retinal layers and synaptic dysfunction that cause progressive vision loss with age. Analysis of differential gene expression profiles and pathway enrichment analysis of Rs1-KO (Rs1-/y) retina identified cell surface receptor signaling and positive regulation of cell adhesion as potential RS1 gene interaction networks. Most importantly, it also showed massive dysregulation of immune response genes at early age, with characteristics of a microglia-driven proinflammatory state. Delivery of AAV8-RS1 primed the Rs1-KO retina toward structural and functional recovery. The disease transcriptome transitioned toward a recovery phase with upregulation of genes implicated in wound healing, anatomical structure (camera type eye) development, metabolic pathways, and collagen IV networks that provide mechanical stability to basement membrane. AAV8-RS1 expression also attenuated the microglia gene signatures to low levels toward immune quiescence. This study is among the first to identify RS1 gene interaction networks that underlie retinal structural and functional recovery after RS1 gene therapy. Significantly, it also shows that providing wild-type RS1 gene function caused the retina immune status to transition from a degenerative inflammatory phenotype toward immune quiescence, even though the transgene is not directly linked to microglia function. This study indicates that inhibition of microglial proinflammatory responses is an integral part of therapeutic rescue in XLRS gene therapy, and gene therapy might realize its full potential if delivered before microglia activation and photoreceptor cell death. Clinical Trials. gov Identifier NTC 02317887.
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Affiliation(s)
| | - Yong Zeng
- Section for Translational Research in Retinal and Macular Degeneration
| | | | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul A Sieving
- Department of Ophthalmology, Center for Ocular Regenerative Therapy, School of Medicine, University of California at Davis, Sacramento, CA, USA
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9
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Schmid V, Plössl K, Schmid C, Bernklau S, Weber BHF, Friedrich U. Retinoschisin and Cardiac Glycoside Crosstalk at the Retinal Na/K-ATPase. Invest Ophthalmol Vis Sci 2020; 61:1. [PMID: 32392309 PMCID: PMC7405613 DOI: 10.1167/iovs.61.5.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purpose Mutations in the RS1 gene, which encodes retinoschisin, cause X-linked juvenile retinoschisis, a retinal dystrophy in males. Retinoschisin specifically interacts with the retinal sodium–potassium adenosine triphosphatase (Na/K-ATPase), a transmembrane ion pump. Na/K-ATPases also bind cardiac glycosides, which control the activity of the pump and have been linked to disturbances in retinal homeostasis. In this study, we investigated the crosstalk between retinoschisin and cardiac glycosides at the retinal Na/K-ATPase and the consequences of this interplay on retinal integrity. Methods The effect of cardiac glycosides (ouabain and digoxin) on the binding of retinoschisin to the retinal Na/K-ATPase was investigated via western blot and immunocytochemistry. Also, the influence of retinoschisin on the binding of cardiac glycosides was analyzed via enzymatic assays, which quantified cardiac glycoside-sensitive Na/K-ATPase pump activity. Moreover, retinoschisin-dependent binding of tritium-labeled ouabain to the Na/K-ATPase was determined. Finally, a reciprocal effect of retinoschisin and cardiac glycosides on Na/K-ATPase localization and photoreceptor degeneration was addressed using immunohistochemistry in retinoschisin-deficient murine retinal explants. Results Cardiac glycosides displaced retinoschisin from the retinal Na/K-ATPase; however, retinoschisin did not affect cardiac glycoside binding. Notably, cardiac glycosides reduced the capacity of retinoschisin to regulate Na/K-ATPase localization and to protect against photoreceptor degeneration. Conclusions Our findings reveal opposing effects of retinoschisin and cardiac glycosides on retinal Na/K-ATPase binding and on retinal integrity, suggesting that a fine-tuned interplay between both components is required to maintain retinal homeostasis. This observation provides new insight into the mechanisms underlying the pathological effects of cardiac glycoside treatment on retinal integrity.
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Rathnasamy G, Foulds WS, Ling EA, Kaur C. Retinal microglia - A key player in healthy and diseased retina. Prog Neurobiol 2018; 173:18-40. [PMID: 29864456 DOI: 10.1016/j.pneurobio.2018.05.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/09/2018] [Accepted: 05/29/2018] [Indexed: 01/04/2023]
Abstract
Microglia, the resident immune cells of the brain and retina, are constantly engaged in the surveillance of their surrounding neural tissue. During embryonic development they infiltrate the retinal tissues and participate in the phagocytosis of redundant neurons. The contribution of microglia in maintaining the purposeful and functional histo-architecture of the adult retina is indispensable. Within the retinal microenvironment, robust microglial activation is elicited by subtle changes caused by extrinsic and intrinsic factors. When there is a disturbance in the cell-cell communication between microglia and other retinal cells, for example in retinal injury, the activated microglia can manifest actions that can be detrimental. This is evidenced by activated microglia secreting inflammatory mediators that can further aggravate the retinal injury. Microglial activation as a harbinger of a variety of retinal diseases is well documented by many studies. In addition, a change in the microglial phenotype which may be associated with aging, may predispose the retina to age-related diseases. In light of the above, the focus of this review is to highlight the role played by microglia in the healthy and diseased retina, based on findings of our own work and from that of others.
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Affiliation(s)
- Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore; Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, United States
| | - Wallace S Foulds
- Singapore Eye Research Institute Level 6, The Academia, Discovery Tower, 20 College Road, 169856, Singapore; University of Glasgow, Glasgow, Scotland, G12 8QQ, United Kingdom
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore
| | - Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore.
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11
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Plössl K, Weber BHF, Friedrich U. The X-linked juvenile retinoschisis protein retinoschisin is a novel regulator of mitogen-activated protein kinase signalling and apoptosis in the retina. J Cell Mol Med 2016; 21:768-780. [PMID: 27995734 PMCID: PMC5345684 DOI: 10.1111/jcmm.13019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/26/2016] [Indexed: 02/01/2023] Open
Abstract
X-linked juvenile retinoschisis (XLRS) is a hereditary retinal dystrophy in young males, caused by mutations in the RS1 gene. The function of the encoded protein, termed retinoschisin, and the molecular mechanisms underlying XLRS pathogenesis are still unresolved, although a direct interaction partner of the secreted retinoschisin, the retinal Na/K-ATPase, was recently identified. Earlier gene expression studies in retinoschisin-deficient (Rs1h-/Y ) mice provided a first indication of pathological up-regulation of mitogen-activated protein (MAP) kinase signalling in disease pathogenesis. To further investigate the role for retinoschisin in MAP kinase regulation, we exposed Y-79 cells and murine Rs1h-/Y retinae to recombinant retinoschisin and the XLRS-associated mutant RS1-C59S. Although normal retinoschisin stably bound to retinal cells, RS1-C59S exhibited a strongly reduced binding affinity. Simultaneously, exposure to normal retinoschisin significantly reduced phosphorylation of C-RAF and MAP kinases ERK1/2 in Y-79 cells and murine Rs1h-/Y retinae. Expression of MAP kinase target genes C-FOS and EGR1 was also down-regulated in both model systems. Finally, retinoschisin treatment decreased pro-apoptotic BAX-2 transcript levels in Y-79 cells and Rs1h-/Y retinae. Upon retinoschisin treatment, these cells showed increased resistance against apoptosis, reflected by decreased caspase-3 activity (in Y-79 cells) and increased photoreceptor survival (in Rs1h-/Y retinal explants). RS1-C59S did not influence C-RAF or ERK1/2 activation, C-FOS or EGR1 expression, or apoptosis. Our data imply that retinoschisin is a novel regulator of MAP kinase signalling and exerts an anti-apoptotic effect on retinal cells. We therefore discuss that disturbances of MAP kinase signalling by retinoschisin deficiency could be an initial step in XLRS pathogenesis.
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Affiliation(s)
- Karolina Plössl
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Ulrike Friedrich
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
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12
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Apaolaza P, del Pozo-Rodríguez A, Torrecilla J, Rodríguez-Gascón A, Rodríguez J, Friedrich U, Weber B, Solinís M. Solid lipid nanoparticle-based vectors intended for the treatment of X-linked juvenile retinoschisis by gene therapy: In vivo approaches in Rs1h-deficient mouse model. J Control Release 2015; 217:273-83. [DOI: 10.1016/j.jconrel.2015.09.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/16/2015] [Accepted: 09/18/2015] [Indexed: 11/25/2022]
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13
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Byrne LC, Oztürk BE, Lee T, Fortuny C, Visel M, Dalkara D, Schaffer DV, Flannery JG. Retinoschisin gene therapy in photoreceptors, Müller glia or all retinal cells in the Rs1h-/- mouse. Gene Ther 2014; 21:585-92. [PMID: 24694538 PMCID: PMC4047144 DOI: 10.1038/gt.2014.31] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 01/28/2014] [Accepted: 02/25/2014] [Indexed: 01/21/2023]
Abstract
X-linked retinoschisis, a disease characterized by splitting of the retina, is caused by mutations in the retinoschisin gene, which encodes a secreted cell adhesion protein. Currently, there is no effective treatment for retinoschisis, though viral vector-mediated gene replacement therapies offer promise. We used intravitreal delivery of three different AAV vectors to target delivery of the RS1 gene to Müller glia, photoreceptors, or multiple cell types throughout the retina. Müller glia radially span the entire retina, are accessible from the vitreous, and remain intact throughout progression of the disease. However, photoreceptors, not glia, normally secrete retinoschisin. We compared the efficacy of rescue mediated by retinoschisin secretion from these specific subtypes of retinal cells in the Rs1h−/− mouse model of retinoschisis. Our results indicate that all three vectors deliver the RS1 gene, and that several cell types can secrete retinoschisin, leading to transport of the protein across the retina. The greatest long-term rescue was observed when photoreceptors produce retinoschisin. Similar rescue was observed with photoreceptor-specific or generalized expression, though photoreceptor secretion may contribute to rescue in the latter case. These results collectively point to the importance of cell targeting and appropriate vector choice in the success of retinal gene therapies.
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Affiliation(s)
- L C Byrne
- 1] Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [2] Department of Chemical and Biomolecular Engineering, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [3] Department of Bioengineering, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA
| | - B E Oztürk
- Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA
| | - T Lee
- Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA
| | - C Fortuny
- 1] Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [2] Department of Vision Science, The University of California, Berkeley, CA, USA
| | - M Visel
- Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA
| | - D Dalkara
- 1] Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [2] Department of Chemical and Biomolecular Engineering, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [3] Department of Bioengineering, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA
| | - D V Schaffer
- 1] Department of Chemical and Biomolecular Engineering, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [2] Department of Bioengineering, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA
| | - J G Flannery
- 1] Department of Molecular and Cellular Biology, The Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA [2] Department of Vision Science, The University of California, Berkeley, CA, USA
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Janssen A, Min SH, Molday LL, Tanimoto N, Seeliger MW, Hauswirth WW, Molday RS, Weber BHF. Effect of Late-stage Therapy on Disease Progression in AAV-mediated Rescue of Photoreceptor Cells in the Retinoschisin-deficient Mouse. Mol Ther 2008; 16:1010-7. [DOI: 10.1038/mt.2008.57] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Fogarasi M, Janssen A, Weber BHF, Stöhr H. Molecular dissection of TIMP3 mutation S156C associated with Sorsby fundus dystrophy. Matrix Biol 2008; 27:381-92. [PMID: 18295466 DOI: 10.1016/j.matbio.2008.01.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 12/20/2007] [Accepted: 01/22/2008] [Indexed: 01/09/2023]
Abstract
Sorsby fundus dystrophy (SFD) is an autosomal dominant macular degeneration of late onset. A key feature of the disease is the thickening of Bruch's membrane, an ECM structure located between the RPE and the choroid. SFD is caused by mutations in the gene encoding the ECM-associated tissue inhibitor of metalloproteases-3 (TIMP3). We have recently generated two Timp3 gene-targeted mouse lines, one deficient for the murine gene (Timp3-/-) and one carrying an SFD-related S156C mutation. Based on extracts and cell cultures derived from tissues of these animals we now evaluated TIMP3 functionality and its contribution to SFD. We show that the activity levels of TIMP3 target proteases including TACE, ADAMTS4/5 and aggrecan-cleaving MMPs are similar in Timp3S156/+ and Timp3S156C/S156C mice when compared to controls. In Timp3-/- mice, a significant enhancement of enzyme activity was observed for TACE but not for ADAMTS4/5 and MMPs indicating a compensatory effect of other inhibitors regulating the latter two groups of proteases. Fibrin bead assays show that angiogenesis in Timp3S156/+ and Timp3S156C/S156C mice is not altered whereas increased formation of capillary tubes was observed in Timp3-/- animals over controls. Rescue experiments using recombinant proteins demonstrate that the inhibitory activities of TIMP3 towards TACE and aggrecan-cleaving MMPs as well as the anti-angiogenic properties of TIMP3 are not impaired by SFD mutation S156C. We finally demonstrate that wild-type and S156C-TIMP3 proteins block the binding of VEGF to its receptor VEGFR2 to a similar extent. Taken together, this study shows that S156C-TIMP3 retains its known functional properties suggesting that causes other than an imbalance in protease or angiogenic activities represent the primary molecular defect underlying SFD.
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Affiliation(s)
- Marton Fogarasi
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany
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ERG variability in X-linked congenital retinoschisis patients with mutations in the RS1 gene and the diagnostic importance of fundus autofluorescence and OCT. Doc Ophthalmol 2007; 116:97-109. [DOI: 10.1007/s10633-007-9094-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 10/16/2007] [Indexed: 11/27/2022]
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Abstract
Microglia cells are phagocytic sentinels in the CNS and in the retina required for neuronal homeostasis and innate immune defense. Accumulating experimental evidence suggests that chronic microglia activation is associated with various neurodegenerative diseases including retinal dystrophies. Endogenous triggers alert microglia cells rapidly in the degenerating retina, leading to local proliferation, migration, enhanced phagocytosis, and secretion of cytokines, chemokines, and neurotoxins. This amplified, immunological cascade and the loss of limiting control mechanisms may contribute significantly to retinal tissue damage and proapoptotic events. This review summarizes the developmental and immune surveillance functions of microglia in the healthy retina and discusses early signaling events and transcriptional networks of microglia activation in retinal degeneration. The characterization of activation pathways at the molecular level may lead to innovative, therapeutic options in degenerative retinal diseases based on a selective, pharmacological interference with the neurotoxic activities of microglia cells, without compromising their homeostastic functions.
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Affiliation(s)
- Thomas Langmann
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
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