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Minella AL, Narfström Wiechel K, Petersen-Jones SM. Alternative splicing in CEP290 mutant cats results in a milder phenotype than LCA CEP290 patients. Vet Ophthalmol 2023; 26:4-11. [PMID: 36495011 PMCID: PMC10107307 DOI: 10.1111/vop.13052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/28/2022] [Accepted: 12/02/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE The rdAc cat has an intronic mutation in the centrosomal 290 kDa (CEP290) gene resulting in a frameshift and a premature stop codon (c.6960 + 9 T > G, p.Ile2321AlafsTer3) predicted to truncate the protein by 157 amino acids. CEP290 mutations in human patients cause a range or phenotypes including syndromic conditions and severe childhood loss of vision while the rdAc cat has a milder phenotype. We sought to further characterize the effect of rdAc mutation on CEP290 expression. METHODS TaqMan quantitative real-time polymerase chain reaction assays were used to compare wildtype and truncated transcript levels. Relative protein abundance was analyzed by Western blot. Immunohistochemistry (IHC) was performed to detect CEP290 protein. RESULTS CEP290 mutant cats show low-level (17.4% of wildtype cats) use of the wildtype splice site and usage of the mutant splice site. Western analysis shows retina from cats homozygous for the mutation has CEP290 protein that likely comprises a combination of both wildtype and truncated protein. IHC detects CEP290 in affected and control retina labeling the region of the interconnecting cilium. CONCLUSIONS The comparably milder phenotype of CEP290 mutant cats is likely due to the retained production of some full-length CEP290 protein with possible functional contributions from presence of truncated protein.
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Affiliation(s)
- Andrea L Minella
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Kristina Narfström Wiechel
- Department of Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, Mssouri, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
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2
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Pupillary reflex and behavioral masking responses to light as functional measures of retinal degeneration in mice. PLoS One 2021; 16:e0244702. [PMID: 33493166 PMCID: PMC7833141 DOI: 10.1371/journal.pone.0244702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/09/2021] [Indexed: 12/16/2022] Open
Abstract
Background Pre-clinical testing of retinal pathology and treatment efficacy depends on reliable and valid measures of retinal function. The electroretinogram (ERG) and tests of visual acuity are the ideal standard, but can be unmeasurable while useful vision remains. Non-image-forming responses to light such as the pupillary light reflex (PLR) are attractive surrogates. However, it is not clear how accurately such responses reflect changes in visual capability in specific disease models. The purpose of this study was to test whether measures of non-visual responses to light correlate with previously determined visual function in two photoreceptor degenerations. Methods The sensitivity of masking behavior (light induced changes in running wheel activity) and the PLR were measured in 3-month-old wild-type mice (WT) with intact inner retinal circuitry, Pde6b-rd1/rd1 mice (rd1) with early and rapid loss of rods and cones, and Prph2-Rd2/Rd2 mice (Rd2) with a slower progressive loss of rods and cones. Results In rd1 mice, negative masking had increased sensitivity, positive masking was absent, and the sensitivity of the PLR was severely reduced. In Rd2 mice, positive masking identified useful vision at higher light levels, but there was a limited decrease in the irradiance sensitivity of negative masking and the PLR, and the amplitude of change for both underestimated the reduction in irradiance sensitivity of image-forming vision. Conclusions Together these data show that in a given disease, two responses to light can be affected in opposite ways, and that for a given response to light, the change in the response does not accurately represent the degree of pathology. However, the extent of the deficit in the PLR means that even a limited rescue of rod/cone function might be measured by increased PLR amplitude. In addition, positive masking has the potential to measure effective treatment in both models by restoring responses or shifting thresholds to lower irradiances.
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Thompson S, Blodi FR, Larson DR, Anderson MG, Stasheff SF. The Efemp1R345W Macular Dystrophy Mutation Causes Amplified Circadian and Photophobic Responses to Light in Mice. Invest Ophthalmol Vis Sci 2019; 60:2110-2117. [PMID: 31095679 PMCID: PMC6735810 DOI: 10.1167/iovs.19-26881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose The R345W mutation in EFEMP1 causes malattia leventinese, an autosomal dominant eye disease with pathogenesis similar to an early-onset age-related macular degeneration. In mice, Efemp1R345W does not cause detectable degeneration but small subretinal deposits do accumulate. The purpose of this study was to determine whether there were abnormal responses to light at this presymptomatic stage in Efemp1R345W mice. Methods Responses to light were assessed by visual water task, circadian phase shifting, and negative masking behavior. The mechanism of abnormal responses was investigated by anterior eye exam, electroretinogram, melanopsin cell quantification, and multielectrode recording of retinal ganglion cell activity. Results Visual acuity was not different in Efemp1R345W mice. However, amplitudes of circadian phase shifting (P = 0.016) and negative masking (P < 0.0001) were increased in Efemp1R345W mice. This phenotype was not explained by anterior eye defects or amplified outer retina responses. Instead, we identified increased melanopsin-generated responses to light in the ganglion cell layer of the retina (P < 0.01). Conclusions Efemp1R345W increases the sensitivity to light of behavioral responses driven by detection of irradiance. An amplified response to light in melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) is consistent with this phenotype. The major concern with this effect of the malattia leventinese mutation is the potential for abnormal regulation of physiology by light to negatively affect health.
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Affiliation(s)
- Stewart Thompson
- Department of Psychology, New Mexico Tech, Socorro, New Mexico, United States.,Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States.,Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States
| | - Frederick R Blodi
- Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States.,Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States.,Pediatrics, University of Iowa, Iowa City, Iowa, United States.,Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States
| | - Demelza R Larson
- Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States.,Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States.,Biology Department, College of St. Benedict & St. John's University, Collegeville, Minnesota, United States
| | - Michael G Anderson
- Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States.,Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States.,Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States.,VA Center for Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Steven F Stasheff
- Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States.,Pediatrics, University of Iowa, Iowa City, Iowa, United States.,Unit on Retinal Neurophysiology, National Eye Institute, Bethesda, Maryland, United States.,Center for Neurosciences and Behavioral Medicine, Children's National Medical Center, Washington, DC, United States.,George Washington University School of Medicine and Health Sciences, Washington, DC, United States
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4
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Douglas RH. The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions. Prog Retin Eye Res 2018; 66:17-48. [PMID: 29723580 DOI: 10.1016/j.preteyeres.2018.04.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 11/28/2022]
Abstract
The timecourse and extent of changes in pupil area in response to light are reviewed in all classes of vertebrate and cephalopods. Although the speed and extent of these responses vary, most species, except the majority of teleost fish, show extensive changes in pupil area related to light exposure. The neuromuscular pathways underlying light-evoked pupil constriction are described and found to be relatively conserved, although the precise autonomic mechanisms differ somewhat between species. In mammals, illumination of only one eye is known to cause constriction in the unilluminated pupil. Such consensual responses occur widely in other animals too, and their function and relation to decussation of the visual pathway is considered. Intrinsic photosensitivity of the iris muscles has long been known in amphibia, but is in fact widespread in other animals. The functions of changes in pupil area are considered. In the majority of species, changes in pupil area serve to balance the conflicting demands of high spatial acuity and increased sensitivity in different light levels. In the few teleosts in which pupil movements occur they do not serve a visual function but play a role in camouflaging the eye of bottom-dwelling species. The occurrence and functions of the light-independent changes in pupil size displayed by many animals are also considered. Finally, the significance of the variations in pupil shape, ranging from circular to various orientations of slits, ovals, and other shapes, is discussed.
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Affiliation(s)
- Ronald H Douglas
- Division of Optometry & Visual Science City, University of London, Northampton Square, London, EC1V 0HB, United Kingdom.
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Collison FT, Park JC, Fishman GA, McAnany JJ, Stone EM. Full-Field Pupillary Light Responses, Luminance Thresholds, and Light Discomfort Thresholds in CEP290 Leber Congenital Amaurosis Patients. Invest Ophthalmol Vis Sci 2016; 56:7130-6. [PMID: 26529047 DOI: 10.1167/iovs.15-17467] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
PURPOSE To investigate visual function in patients with CEP290 Leber congenital amaurosis (LCA-CEP290), using three full-field tests that can be performed by patients with poor fixation. METHODS Six patients (age range, 9-39 years) with LCA-CEP290 participated in the study. Stimuli for all three tests (full-field stimulus test [FST], pupillometry, and light discomfort threshold [LDT] testing) were generated by the Diagnosys ColorDome ganzfeld, by using achromatic stimuli as well as long- and short-wavelength stimuli to target rod and cone photoreceptors with all three tests and, in the latter two tests, melanopsin photoreceptors. RESULTS Dark-adapted FST thresholds in LCA-CEP290 patients were cone mediated and elevated between 4.8 and 6.2 log units above the normal achromatic threshold. The FST threshold was not measurable in one patient. The rod-mediated transient pupillary light reflex (PLR) was absent in all but the youngest patient, where unreliable responses precluded PLR quantification. Cone-mediated transient PLRs were subnormal in five patients, and absent in another. Sustained melanopsin-mediated PLRs were measurable in all patients. Full-field LDT thresholds were elevated compared to normal controls, and were lower for short-wavelengh than for long-wavelength stimuli. CONCLUSIONS The FST thresholds and transient PLRs were cone mediated in our cohort LCA-CEP290 patients. Rod-mediated PLRs were undetectable, whereas melanopsin-mediated sustained responses were detected in all patients, suggesting a relative preservation of inner-retina function. The LDT elevations for the patients are somewhat paradoxical, given their subjective perception of photoaversion. Relative aversion to short-wavelength light suggests influence from melanopsin on LDTs in these patients.
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Affiliation(s)
- Frederick T Collison
- The Pangere Center for Inherited Retinal Diseases The Chicago Lighthouse for People Who Are Blind or Visually Impaired, Chicago, Illinois, United States
| | - Jason C Park
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States
| | - Gerald A Fishman
- The Pangere Center for Inherited Retinal Diseases The Chicago Lighthouse for People Who Are Blind or Visually Impaired, Chicago, Illinois, United States 2Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicin
| | - J Jason McAnany
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States
| | - Edwin M Stone
- The University of Iowa Carver College of Medicine, Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Howard Hughes Medical Institute, Iowa City, Iowa, United States
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Svensson M, Olsén L, Winkler PA, Petersen-Jones SM, Bergström T, Garncarz Y, Narfström K. Progressive retinal atrophy in the Polski Owczarek Nizinny dog: a clinical and genetic study. Vet Ophthalmol 2015; 19:195-205. [PMID: 26009980 DOI: 10.1111/vop.12284] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To describe ophthalmic, functional, structural, and genetical characteristics of progressive retinal atrophy (PRA) in the polski owczarek nizinny (PON) breed of dog. ANIMALS STUDIED CLINICALLY Client-owned PON dogs (n = 82) from Sweden. PROCEDURES Routine examination for presumed inherited eye disease was performed in all dogs. Bilateral full-field electroretinography (ERG) was performed in 11 affected and 4 control dogs. Eyes from one affected dog were studied with light microscopy. DNA samples from 34 Swedish and 30 PON dogs collected by Michigan State University (MSU) were tested for the mutations causing the rcd4 and prcd forms of PRA. RESULTS Sixteen of the eighty-two Swedish dogs were diagnosed with PRA. Slight vascular attenuation, first seen at 4.5 years of age, preceded changes in tapetal reflectivity. The initial ERG changes in affected dogs showed markedly diminished rod responses, while cone responses were barely affected. Eventually, cone responses were also reduced. Retinal morphology showed approximately a 50% reduction of photoreceptor nuclei in the outer nuclear layer. Fourteen of fifteen PRA-affected Swedish dogs and eighteen of twenty of the MSU PRA-affected dogs tested genetically were positive for the rcd4 mutation. All tested dogs were negative for the mutation causing prcd-PRA. CONCLUSIONS PRA of PON dogs is a late-onset degenerative disease with slow progression. There is early loss of rod function, while the cone system deteriorates later. The rcd4 mutation in the C2ORF71 gene was associated with the majority of the PRA cases tested. The possibility of additional forms of PRA in the breed cannot be excluded.
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Affiliation(s)
- Marika Svensson
- Blue Star Animal Hospital, Gjutjärnsgatan 4, Gothenburg, 417 07, Sweden
| | - Lena Olsén
- Division of Pharmacology and Toxicology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, SE-750 07, Sweden
| | - Paige A Winkler
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road D, 208, East Lansing, MI, USA.,Genetics Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road D, 208, East Lansing, MI, USA.,Genetics Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Tomas Bergström
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Yacek Garncarz
- Veterinary Eye Clinic, Grupy AK Polnoc 2/u10, Warsaw, 00-713, Poland
| | - Kristina Narfström
- College of Veterinary Medicine, 900 East Campus Drive, Columbia, MO, 65211, USA.,Retvet KB, Karlsuddsvägen 14b, Vaxholm, 185 93, Sweden
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Whiting REH, Yao G, Narfström K, Pearce JW, Coates JR, Dodam JR, Castaner LJ, Katz ML. Quantitative assessment of the canine pupillary light reflex. Invest Ophthalmol Vis Sci 2013; 54:5432-40. [PMID: 23847311 DOI: 10.1167/iovs.13-12012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To develop instrumentation and methods for thorough quantitative assessment of the pupillary light reflex (PLR) in dogs under varying stimulus conditions. METHODS The PLR was recorded in normal Dachshunds using a custom system allowing full user control over stimulus intensity, color, and duration. Chemical restraint protocols were compared to determine which protocol provided for optimal baseline stability of pupil size and appropriate eye positioning. A series of white light stimuli of increasing intensity was used to elicit pupil constriction. Pupil images were concurrently recorded using continuous infrared illumination and an infrared-sensitive camera. The PLR was also recorded in response to blue and red stimuli. RESULTS With injectable chemical restraint alone, spontaneous fluctuations in pupil size occurred independent of light stimulation, and spontaneous eye movements made it difficult to fully visualize the pupil. Combined injectable chemical and inhalation restraint provided a steady baseline pupil size throughout PLR assessment and allowed for stable positioning of the eye using a conjunctival stay suture. Robust PLRs were elicited with all light colors. PLR constriction amplitude increased with increasing flash intensity and ranged from 5% to 70%. CONCLUSIONS A recording system and protocol have been developed to reliably quantify the canine PLR. The techniques and instrumentation will be useful for objective quantitative assessment of the PLR in dogs and other species in research applications and may be useful in clinical veterinary ophthalmology and neurology if PLR abnormalities detected with these procedures can be associated with specific diseases.
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Affiliation(s)
- Rebecca E H Whiting
- Department of Biological Engineering, College of Engineering, University of Missouri, Columbia, Missouri 65212, USA
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The domestic cat as a large animal model for characterization of disease and therapeutic intervention in hereditary retinal blindness. J Ophthalmol 2011; 2011:906943. [PMID: 21584261 PMCID: PMC3090773 DOI: 10.1155/2011/906943] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/04/2010] [Accepted: 01/24/2011] [Indexed: 01/09/2023] Open
Abstract
Large mammals, including canids and felids, are affected by spontaneously occurring hereditary retinal diseases with similarities to those of humans. The large mammal models may be used for thorough clinical characterization of disease processes, understanding the effects of specific mutations, elucidation of disease mechanisms, and for development of therapeutic intervention. Two well-characterized feline models are addressed in this paper. The first model is the autosomal recessive, slowly progressive, late-onset, rod-cone degenerative disease caused by a mutation in the CEP290 gene. The second model addressed in this paper is the autosomal dominant early onset rod cone dysplasia, putatively caused by the mutation found in the CRX gene. Therapeutic trials have been performed mainly in the former type including stem cell therapy, retinal transplantation, and development of ocular prosthetics. Domestic cats, having large human-like eyes with comparable spontaneous retinal diseases, are also considered useful for gene replacement therapy, thus functioning as effective model systems for further research.
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Coppieters F, Lefever S, Leroy BP, De Baere E. CEP290, a gene with many faces: mutation overview and presentation of CEP290base. Hum Mutat 2011; 31:1097-108. [PMID: 20690115 DOI: 10.1002/humu.21337] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ciliopathies are an emerging group of disorders, caused by mutations in ciliary genes. One of the most intriguing disease genes associated with ciliopathies is CEP290, in which mutations cause a wide variety of distinct phenotypes, ranging from isolated blindness over Senior-Loken syndrome (SLS), nephronophthisis (NPHP), Joubert syndrome (related disorders) (JS[RD]), Bardet-Biedl syndrome (BBS), to the lethal Meckel-Grüber syndrome (MKS). Despite the identification of over 100 unique CEP290 mutations, no clear genotype-phenotype correlations could yet be established, and consequently the predictive power of a CEP290-related genotype remains limited. One of the challenges is a better understanding of second-site modifiers. In this respect, there is a growing interest in the potential modifying effects of variations in genes encoding other members of the ciliary proteome that interact with CEP290. Here, we provide an overview of all CEP290 mutations identified so far, with their associated phenotypes. To this end, we developed CEP290base, a locus-specific mutation database that links mutations with patients and their phenotypes (medgen.ugent.be/cep290base).
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Affiliation(s)
- Frauke Coppieters
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
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