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Pattanaik DK, Lakshminarayanan V, Sharma NK, Sahu AP. Leading edge of the a-wave of the electroretinogram and sodium iodate-induced age-related macular degeneration: A model. J Theor Biol 2024; 592:111879. [PMID: 38909882 DOI: 10.1016/j.jtbi.2024.111879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 05/12/2024] [Accepted: 06/10/2024] [Indexed: 06/25/2024]
Abstract
BACKGROUND Iron-induced oxidative stress was thought to be the reason why the a-wave amplitude of the electroretinogram (ERG) dropped when iron ions were present. It is assumed that reactive oxygen species (ROS) are generated in the presence of iron ions, and this leads to a decrease in hyperpolarization of the photoreceptor. It is known that in age-related macular degeneration (AMD), sodium iodate can induce oxidative stress, apoptosis, and retinal damage, which mimic the effects of clinical AMD. Here, the reduction of the a-wave amplitude in mice with sodium iodate-induced age-related macular degeneration is explained. METHODS The leading edge of the a-wave is divided into voltages developed by cones and rods. The same oxidative stress model is applied here since sodium iodate causes the creation of ROS in a manner similar to that caused by iron ions, with the exception that the retina is treated as a circuit of various resistances when computing the photoresponse. Moreover, sodium iodate also leads to apoptosis and, hence, may cause misalignment in cones (not in rods) during the initial stage of apoptosis in AMD. To include the effects of apoptosis and shortening in cones and rods, we have used a factor representing the fraction of total cones and rods that are alive. To include the effect of misalignment of cones on the reduction of the a-wave amplitude, we have used the Stiles-Crawford function to calculate the number of photoisomerizations occurring in a photoreceptor misaligned at an angle θ. The results are compared with experimental data. RESULTS In sodium iodate-treated eyes, the ROS produced can attract calcium ions in the photoreceptor, which increases the calcium influx. In the case of the cones, the inclusion of the misalignment angle in the phototransduction process helps in determining the voltage and slope of the voltage vs. time graph.The smaller the fraction of active photoreceptors, the smaller the amplitude of the a-wave. The calcium influx, misaligned photoreceptors, and total photoreceptor loss all cause the amplitude of the a-wave to decrease, and at any time from the beginning of phototransduction cascade, the calcium influx causes the slope of the a-wave to increase. CONCLUSION The reduction in the a-wave amplitude in the eyes of sodium iodate-treated mice is attributed to oxidative stress in both cones and rods and cone misalignment, which ultimately lead to apoptosis and vision loss in AMD.
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Affiliation(s)
| | - Vasudevan Lakshminarayanan
- School of Optometry and Vision Science and Departments of Physics, Electrical and Computer Engineering and System Design Engineering, University of Waterloo, Waterloo, Canada.
| | | | - Amir Prasad Sahu
- Centurion University of Technology and Management, Bhubaneswar, OR, India.
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2
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Carrero L, Antequera D, Municio C, Carro E. Circadian rhythm disruption and retinal dysfunction: a bidirectional link in Alzheimer's disease? Neural Regen Res 2024; 19:1967-1972. [PMID: 38227523 DOI: 10.4103/1673-5374.390962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 11/07/2023] [Indexed: 01/17/2024] Open
Abstract
Dysfunction in circadian rhythms is a common occurrence in patients with Alzheimer's disease. A predominant function of the retina is circadian synchronization, carrying information to the brain through the retinohypothalamic tract, which projects to the suprachiasmatic nucleus. Notably, Alzheimer's disease hallmarks, including amyloid-β, are present in the retinas of Alzheimer's disease patients, followed/associated by structural and functional disturbances. However, the mechanistic link between circadian dysfunction and the pathological changes affecting the retina in Alzheimer's disease is not fully understood, although some studies point to the possibility that retinal dysfunction could be considered an early pathological process that directly modulates the circadian rhythm.
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Affiliation(s)
- Laura Carrero
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain; Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain
- PhD Program in Neuroscience, Autonoma de Madrid University, Madrid, Spain
| | - Desireé Antequera
- Neurobiology of Alzheimer's Disease Unit, Functional Unit for Research into Chronic Diseases, Instituto de Salud Carlos III, Madrid, Spain; Network Centre for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain
| | - Cristina Municio
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain; Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain
| | - Eva Carro
- Neurobiology of Alzheimer's Disease Unit, Functional Unit for Research into Chronic Diseases, Instituto de Salud Carlos III, Madrid, Spain; Network Centre for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain
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3
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Fung W, Kolotuev I, Heiman MG. Specialized structure and function of the apical extracellular matrix at sense organs. Cells Dev 2024; 179:203942. [PMID: 39067521 PMCID: PMC11346620 DOI: 10.1016/j.cdev.2024.203942] [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: 05/03/2024] [Revised: 07/21/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
Apical extracellular matrix (aECM) covers every surface of the body and exhibits tissue-specific structures that carry out specialized functions. This is particularly striking at sense organs, where aECM forms the interface between sensory neurons and the environment, and thus plays critical roles in how sensory stimuli are received. Here, we review the extraordinary adaptations of aECM across sense organs and discuss how differences in protein composition and matrix structure assist in sensing mechanical forces (tactile hairs, campaniform sensilla, and the tectorial membrane of the cochlea); tastes and smells (uniporous gustatory sensilla and multiporous olfactory sensilla in insects, and salivary and olfactory mucus in vertebrates); and light (cuticle-derived lenses in arthropods and mollusks). We summarize the power of using C. elegans, in which defined sense organs associate with distinct aECM, as a model for understanding the tissue-specific structural and functional specializations of aECM. Finally, we synthesize results from recent studies in C. elegans and Drosophila into a conceptual framework for aECM patterning, including mechanisms that involve transient cellular or matrix scaffolds, mechanical pulling or pushing forces, and localized secretion or endocytosis.
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Affiliation(s)
- Wendy Fung
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | - Maxwell G Heiman
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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4
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Wang C, Xiong S, Hu S, Yang L, Huang Y, Chen H, Xu B, Xiao T, Liu Q. Genome-wide identification of Gα family in grass carp (Ctenopharyngodon idella) and reproductive regulation functional characteristics of Cignaq. BMC Genomics 2024; 25:800. [PMID: 39182029 PMCID: PMC11344465 DOI: 10.1186/s12864-024-10717-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 08/16/2024] [Indexed: 08/27/2024] Open
Abstract
BACKGROUND The Gα family plays a crucial role in the complex reproductive regulatory network of teleosts. However, the characterization and function of Gα family members, especially Gαq, remain poorly understood in teleosts. To analyze the characterization, expression, and function of grass carp (Ctenopharyngodon idella) Gαq, we identified the Gα family members in grass carp genome, and analyzed the expression, distribution, and signal transduction of Gαq/gnaq. We also explored the role of Gαq in the reproductive regulation of grass carp. RESULTS Our results showed that the grass carp genome contains 27 Gα genes with 46 isoforms, which are divided into four subfamilies: Gαs, Gαi/o, Gαq/11, and Gα12/13. The expression level of Cignaq in the testis was the highest and significantly higher than in other tissues, followed by the hypothalamus and brain. The luteinizing hormone receptor (LHR) was mainly localized to the nucleus in grass carp oocytes, with signals also present in follicular cells. In contrast, Gαq signal was mainly found in the cytoplasm of oocytes, with no signal in follicular cells. In the testis, Gαq and LHR were co-localized in the cytoplasm. Furthermore, the grass carp Gαq recombinant protein significantly promoted Cipgr expression. CONCLUSIONS These results provided preliminary evidence for understanding the role of Gαq in the reproductive regulation of teleosts.
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Affiliation(s)
- Chong Wang
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Shuting Xiong
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Shitao Hu
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Le Yang
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Yuhong Huang
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Haitai Chen
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Baohong Xu
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China
| | - Tiaoyi Xiao
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China.
| | - Qiaolin Liu
- Fisheries College, Hunan Agricultural University, Changsha, 410128, China.
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Kumar D, Khan B, Okcay Y, Sis ÇÖ, Abdallah A, Murray F, Sharma A, Uemura M, Taliyan R, Heinbockel T, Rahman S, Goyal R. Dynamic endocannabinoid-mediated neuromodulation of retinal circadian circuitry. Ageing Res Rev 2024; 99:102401. [PMID: 38964508 DOI: 10.1016/j.arr.2024.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 06/05/2024] [Accepted: 06/28/2024] [Indexed: 07/06/2024]
Abstract
Circadian rhythms are biological rhythms that originate from the "master circadian clock," called the suprachiasmatic nucleus (SCN). SCN orchestrates the circadian rhythms using light as a chief zeitgeber, enabling humans to synchronize their daily physio-behavioral activities with the Earth's light-dark cycle. However, chronic/ irregular photic disturbances from the retina via the retinohypothalamic tract (RHT) can disrupt the amplitude and the expression of clock genes, such as the period circadian clock 2, causing circadian rhythm disruption (CRd) and associated neuropathologies. The present review discusses neuromodulation across the RHT originating from retinal photic inputs and modulation offered by endocannabinoids as a function of mitigation of the CRd and associated neuro-dysfunction. Literature indicates that cannabinoid agonists alleviate the SCN's ability to get entrained to light by modulating the activity of its chief neurotransmitter, i.e., γ-aminobutyric acid, thus preventing light-induced disruption of activity rhythms in laboratory animals. In the retina, endocannabinoid signaling modulates the overall gain of the retinal ganglion cells by regulating the membrane currents (Ca2+, K+, and Cl- channels) and glutamatergic neurotransmission of photoreceptors and bipolar cells. Additionally, endocannabinoids signalling also regulate the high-voltage-activated Ca2+ channels to mitigate the retinal ganglion cells and intrinsically photosensitive retinal ganglion cells-mediated glutamate release in the SCN, thus regulating the RHT-mediated light stimulation of SCN neurons to prevent excitotoxicity. As per the literature, cannabinoid receptors 1 and 2 are becoming newer targets in drug discovery paradigms, and the involvement of endocannabinoids in light-induced CRd through the RHT may possibly mitigate severe neuropathologies.
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Affiliation(s)
- Deepak Kumar
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
| | - Bareera Khan
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India
| | - Yagmur Okcay
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Çağıl Önal Sis
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Aya Abdallah
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Fiona Murray
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Ashish Sharma
- School of Medicine, Washington University, St. Louis, USA
| | - Maiko Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Rajeev Taliyan
- Department of Pharmacy, Birla Institute of Technology Science, Pilani, Rajasthan 333301, India.
| | - Thomas Heinbockel
- Howard University College of Medicine, Department of Anatomy, Washington, DC 20059, USA
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy South Dakota State University, Brookings, SD, USA.
| | - Rohit Goyal
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
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Nouri Z, Sarmadi A, Narrei S, Kianersi H, Kianersi F, Tabatabaiefar MA. Clinical characterizations and molecular genetic study of two co-segregating variants in PDZD7 and PDE6C genes leading simultaneously to non-syndromic hearing loss and achromatopsia. BMC Med Genomics 2024; 17:173. [PMID: 38956522 PMCID: PMC11218353 DOI: 10.1186/s12920-024-01942-3] [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: 10/08/2023] [Accepted: 06/19/2024] [Indexed: 07/04/2024] Open
Abstract
BACKGROUND Autosomal recessive non-syndromic hearing loss (NSHL) and cone dystrophies (CODs) are highly genetically and phenotypically heterogeneous disorders. In this study, we applied the whole exome sequencing (WES) to find the cause of HL and COD in an Iranian consanguineous family with three affected individuals. METHODS Three members from an Iranian consanguineous family who were suffering from NSHL and visual impairment were ascertained in this study. Comprehensive clinical evaluations and genetic analysis followed by bioinformatic and co-segregation studies were performed to diagnose the cause of these phenotypes. Data were collected from 2020 to 2022. RESULTS All cases showed congenital bilateral NSHL, decreased visual acuity, poor color discrimination, photophobia and macular atrophy. Moreover, cornea, iris and anterior vitreous were within normal limit in both eyes, decreased foveal sensitivity, central scotoma and generalized depression of visual field were seen in three cases. WES results showed two variants, a novel null variant (p.Trp548Ter) in the PDE6C gene causing COD type 4 (Achromatopsia) and a previously reported variant (p.Ile84Thr) in the PDZD7 gene causing NSHL. Both variants were found in the cis configuration on chromosome 10 with a genetic distance of about 8.3 cM, leading to their co-inheritance. However, two diseases could appear independently in subsequent generations due to crossover during meiosis. CONCLUSIONS Here, we could successfully determine the etiology of a seemingly complex phenotype in two adjacent genes. We identified a novel variant in the PDE6C gene, related to achromatopsia. Interestingly, this variant could cooperatively cause visual disorders: cone dystrophy and cone-rod dystrophy.
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Affiliation(s)
- Zahra Nouri
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
- Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Akram Sarmadi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
- Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Sina Narrei
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
- Department of Research and Development, Harmonic Medical Genetics Lab, Isfahan, Iran
| | - Hamidreza Kianersi
- Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Farzan Kianersi
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Amin Tabatabaiefar
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
- Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.
- University of Medical Sciences, Isfahan, 81746-73461, Iran.
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Binelli A, Nigro L, Sbarberi R, Della Torre C, Magni S. To be or not to be plastics? Protein modulation and biochemical effects in zebrafish embryos exposed to three water-soluble polymers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167699. [PMID: 37832656 DOI: 10.1016/j.scitotenv.2023.167699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/26/2023] [Accepted: 10/07/2023] [Indexed: 10/15/2023]
Abstract
Water-soluble polymers (WSPs) are a particular category of polymers that, due to their capability to be soluble in water, come out of the classic definition of plastic and therefore also from its regulation and control, representing a possible new environmental problem considering the number of consumer products in which they are contained. For this reason, the aim of this study was to evaluate the possible adverse effects of three of the most used WSPs (polyacrylic acid - PAA, polyethylene glycol - PEG, polyvinylpyrrolidone - PVP), administered at relevant environmental concentrations (0.001, 0.5 and 1 mg/L) to Danio rerio (zebrafish) embryos up to 120 h post fertilization. To assess the WSP toxicity at the molecular, cellular and organism level we used an integrated ecotoxicological approach of both biomarkers and high-throughput technology based on gel-free proteomics. The main results showed how all the three WSPs up-regulated many proteins (up to 74 in specimens exposed to 1 mg/L PVP) with a wide range of molecular functions and involved in numerous cellular pathways of exposed specimens. On the other hand, the measurement of biomarkers showed how PAA and PVP were able to activate the antioxidant machinery following an over-production of reactive oxygen species, while PEG produced no significant changes in the biomarkers measured. Based on the obtained results, the use and application of WSPs should be revised and regulated.
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Affiliation(s)
- Andrea Binelli
- University of Milan, Department of Biosciences, Via Celoria 26, 20133 Milan, Italy
| | - Lara Nigro
- University of Milan, Department of Biosciences, Via Celoria 26, 20133 Milan, Italy.
| | - Riccardo Sbarberi
- University of Milan, Department of Biosciences, Via Celoria 26, 20133 Milan, Italy
| | - Camilla Della Torre
- University of Milan, Department of Biosciences, Via Celoria 26, 20133 Milan, Italy
| | - Stefano Magni
- University of Milan, Department of Biosciences, Via Celoria 26, 20133 Milan, Italy
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Conti GM, Cancellieri F, Quinodoz M, Kaminska K, Vaclavik V, Rivolta C, Tran HV. GNB1-Related Rod-Cone Dystrophy: A Case Report. Case Rep Ophthalmol 2024; 15:230-237. [PMID: 38500542 PMCID: PMC10948171 DOI: 10.1159/000537997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 02/19/2024] [Indexed: 03/20/2024] Open
Abstract
Introduction The GNB1 (guanine nucleotide-binding protein, β1) gene encodes for the ubiquitous β1 subunit of heterotrimeric G proteins, which are associated with G-protein-coupled receptors (GPCRs). GNB1 mutations cause a neurodevelopmental disorder characterized by a broad clinical spectrum. A novel variant has recently been confirmed in a case of rod-cone dystrophy. Case Presentation We describe the second confirmed case of a classical rod-cone dystrophy associated with a mutation located in exon 6 of GNB1 [NM_002074.5:c.217G>C, p.(Ala73Pro)] in a 56-year-old patient also presenting mild intellectual disability, attention deficit/hyperactivity disorder, and truncal obesity. Conclusion This paper confirms the role of GNB1 in the pathogenesis of a classic rod-cone dystrophy and highlights the importance of including this gene in the genetic analysis panel for inherited retinal diseases.
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Affiliation(s)
- Giovanni Marco Conti
- Genetic Ophthalmic Department, Hôpital Ophtalmique Jules-Gonin, University of Lausanne and Faculty of Life Sciences, Lausanne, Switzerland
- Institut D’Ophtalmologie de Vevey (INOV), Vevey, Switzerland
| | - Francesca Cancellieri
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Mathieu Quinodoz
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
- Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Karolina Kaminska
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Veronika Vaclavik
- Genetic Ophthalmic Department, Hôpital Ophtalmique Jules-Gonin, University of Lausanne and Faculty of Life Sciences, Lausanne, Switzerland
| | - Carlo Rivolta
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
- Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Hoai Viet Tran
- Genetic Ophthalmic Department, Hôpital Ophtalmique Jules-Gonin, University of Lausanne and Faculty of Life Sciences, Lausanne, Switzerland
- Institut D’Ophtalmologie de Vevey (INOV), Vevey, Switzerland
- Centre for Gene Therapy and Regenerative Medicine, King’s College London, London, UK
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9
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Riaz S, Sethna S, Duncan T, Naeem MA, Redmond TM, Riazuddin S, Riazuddin S, Carvalho LS, Ahmed ZM. Dual AAV-based PCDH15 gene therapy achieves sustained rescue of visual function in a mouse model of Usher syndrome 1F. Mol Ther 2023; 31:3490-3501. [PMID: 37864333 PMCID: PMC10727994 DOI: 10.1016/j.ymthe.2023.10.017] [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: 06/15/2023] [Revised: 09/20/2023] [Accepted: 10/18/2023] [Indexed: 10/22/2023] Open
Abstract
Mutations in the PCDH15 gene, encoding protocadherin-15, are among the leading causes of Usher syndrome type 1 (USH1F), and account for up to 12% USH1 cases worldwide. A founder truncating variant of PCDH15 has a ∼2% carrier frequency in Ashkenazi Jews accounting for nearly 60% of their USH1 cases. Although cochlear implants can restore hearing perception in USH1 patients, presently there are no effective treatments for the vision loss due to retinitis pigmentosa. We established a founder allele-specific Pcdh15 knockin mouse model as a platform to ascertain therapeutic strategies. Using a dual-vector approach to circumvent the size limitation of adeno-associated virus, we observed robust expression of exogenous PCDH15 in the retinae of Pcdh15KI mice, sustained recovery of electroretinogram amplitudes and key retinoid oxime, substantially improved light-dependent translocation of phototransduction proteins, and enhanced levels of retinal pigment epithelium-derived enzymes. Thus, our data raise hope and pave the way for future gene therapy trials in USH1F subjects.
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Affiliation(s)
- Sehar Riaz
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - Saumil Sethna
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Muhammad A Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sheikh Riazuddin
- Jinnah Burn and Reconstructive Surgery Centre, Allama Iqbal Medical Research, University of Health Sciences, Lahore 54500, Pakistan
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Livia S Carvalho
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA 6009, Australia; Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, Nedlands, WA 6009, Australia
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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10
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Liénard MA. Sensory evolution: A dazzling hack to cope with bright light in owls and whales. Curr Biol 2023; 33:R1200-R1202. [PMID: 37989100 DOI: 10.1016/j.cub.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
When exposed to sudden changes in light intensity, rod-dominated retinas of animals with highly sensitive dim-vision risk critical damage. A new study finds that owls and deep-diving whales have evolved an identical photoprotection mechanism to delay toxic all-trans retinal release, a discovery with potential medical implications.
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Affiliation(s)
- Marjorie A Liénard
- Department of Biology, Lund University, Sölvegatan 35B, 22362 Lund, Sweden.
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11
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Plau J, Morgan CE, Fedorov Y, Banerjee S, Adams DJ, Blaner WS, Yu EW, Golczak M. Discovery of Nonretinoid Inhibitors of CRBP1: Structural and Dynamic Insights for Ligand-Binding Mechanisms. ACS Chem Biol 2023; 18:2309-2323. [PMID: 37713257 PMCID: PMC10591915 DOI: 10.1021/acschembio.3c00402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023]
Abstract
The dysregulation of retinoid metabolism has been linked to prevalent ocular diseases including age-related macular degeneration and Stargardt disease. Modulating retinoid metabolism through pharmacological approaches holds promise for the treatment of these eye diseases. Cellular retinol-binding protein 1 (CRBP1) is the primary transporter of all-trans-retinol (atROL) in the eye, and its inhibition has recently been shown to protect mouse retinas from light-induced retinal damage. In this report, we employed high-throughput screening to identify new chemical scaffolds for competitive, nonretinoid inhibitors of CRBP1. To understand the mechanisms of interaction between CRBP1 and these inhibitors, we solved high-resolution X-ray crystal structures of the protein in complex with six selected compounds. By combining protein crystallography with hydrogen/deuterium exchange mass spectrometry, we quantified the conformational changes in CRBP1 caused by different inhibitors and correlated their magnitude with apparent binding affinities. Furthermore, using molecular dynamic simulations, we provided evidence for the functional significance of the "closed" conformation of CRBP1 in retaining ligands within the binding pocket. Collectively, our study outlines the molecular foundations for understanding the mechanism of high-affinity interactions between small molecules and CRBPs, offering a framework for the rational design of improved inhibitors for this class of lipid-binding proteins.
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Affiliation(s)
- Jacqueline Plau
- Department
of Pharmacology, Small Molecule Drug Development Core Facility, Department of Genetics, and Cleveland Center
for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Christopher E. Morgan
- Department
of Pharmacology, Small Molecule Drug Development Core Facility, Department of Genetics, and Cleveland Center
for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
- Department
of Chemistry, Thiel College, Greenville, Pennsylvania 16125, United States
| | - Yuriy Fedorov
- Department
of Pharmacology, Small Molecule Drug Development Core Facility, Department of Genetics, and Cleveland Center
for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Surajit Banerjee
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14850, United States
- Northeastern
Collaborative Access Team, Argonne National
Laboratory, Argonne, Illinois 60439, United States
| | - Drew J. Adams
- Department
of Pharmacology, Small Molecule Drug Development Core Facility, Department of Genetics, and Cleveland Center
for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - William S. Blaner
- Department
of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
| | - Edward W. Yu
- Department
of Pharmacology, Small Molecule Drug Development Core Facility, Department of Genetics, and Cleveland Center
for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Marcin Golczak
- Department
of Pharmacology, Small Molecule Drug Development Core Facility, Department of Genetics, and Cleveland Center
for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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12
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Abtout A, Reingruber J. Analysis of dim-light responses in rod and cone photoreceptors with altered calcium kinetics. J Math Biol 2023; 87:69. [PMID: 37823947 PMCID: PMC10570263 DOI: 10.1007/s00285-023-02005-4] [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: 12/07/2022] [Revised: 09/12/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Rod and cone photoreceptors in the retina of vertebrates are the primary sensory neurons underlying vision. They convert light into an electrical current using a signal transduction pathway that depends on Ca[Formula: see text] feedback. It is known that manipulating the Ca[Formula: see text] kinetics affects the response shape and the photoreceptor sensitivity, but a precise quantification of these effects remains unclear. We have approached this task in mouse retina by combining numerical simulations with mathematical analysis. We consider a parsimonious phototransduction model that incorporates negative Ca[Formula: see text] feedback onto the synthesis of cyclic GMP, and fast buffering reactions to alter the Ca[Formula: see text] kinetics. We derive analytic results for the photoreceptor functioning in sufficiently dim light conditions depending on the photoreceptor type. We exploit these results to obtain conceptual and quantitative insight into how response waveform and amplitude depend on the underlying biophysical processes and the Ca[Formula: see text] feedback. With a low amount of buffering, the Ca[Formula: see text] concentration changes in proportion to the current, and responses to flashes of light are monophasic. With more buffering, the change in the Ca[Formula: see text] concentration becomes delayed with respect to the current, which gives rise to a damped oscillation and a biphasic waveform. This shows that biphasic responses are not necessarily a manifestation of slow buffering reactions. We obtain analytic approximations for the peak flash amplitude as a function of the light intensity, which shows how the photoreceptor sensitivity depends on the biophysical parameters. Finally, we study how changing the extracellular Ca[Formula: see text] concentration affects the response.
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Affiliation(s)
- Annia Abtout
- Institute of Biology, Ecole Normale Supérieure, Paris, France
| | - Jürgen Reingruber
- Institute of Biology, Ecole Normale Supérieure, Paris, France.
- INSERM, U1024, Paris, France.
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13
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McCulloch KJ, Babonis LS, Liu A, Daly CM, Martindale MQ, Koenig KM. Nematostella vectensis exemplifies the exceptional expansion and diversity of opsins in the eyeless Hexacorallia. EvoDevo 2023; 14:14. [PMID: 37735470 PMCID: PMC10512536 DOI: 10.1186/s13227-023-00218-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 09/11/2023] [Indexed: 09/23/2023] Open
Abstract
BACKGROUND Opsins are the primary proteins responsible for light detection in animals. Cnidarians (jellyfish, sea anemones, corals) have diverse visual systems that have evolved in parallel with bilaterians (squid, flies, fish) for hundreds of millions of years. Medusozoans (e.g., jellyfish, hydroids) have evolved eyes multiple times, each time independently incorporating distinct opsin orthologs. Anthozoans (e.g., corals, sea anemones,) have diverse light-mediated behaviors and, despite being eyeless, exhibit more extensive opsin duplications than medusozoans. To better understand the evolution of photosensitivity in animals without eyes, we increased anthozoan representation in the phylogeny of animal opsins and investigated the large but poorly characterized opsin family in the sea anemone Nematostella vectensis. RESULTS We analyzed genomic and transcriptomic data from 16 species of cnidarians to generate a large opsin phylogeny (708 sequences) with the largest sampling of anthozoan sequences to date. We identified 29 opsins from N. vectensis (NvOpsins) with high confidence, using transcriptomic and genomic datasets. We found that lineage-specific opsin duplications are common across Cnidaria, with anthozoan lineages exhibiting among the highest numbers of opsins in animals. To establish putative photosensory function of NvOpsins, we identified canonically conserved protein domains and amino acid sequences essential for opsin function in other animal species. We show high sequence diversity among NvOpsins at sites important for photoreception and transduction, suggesting potentially diverse functions. We further examined the spatiotemporal expression of NvOpsins and found both dynamic expression of opsins during embryonic development and sexually dimorphic opsin expression in adults. CONCLUSIONS These data show that lineage-specific duplication and divergence has led to expansive diversity of opsins in eyeless cnidarians, suggesting opsins from these animals may exhibit novel biochemical functions. The variable expression patterns of opsins in N. vectensis suggest opsin gene duplications allowed for a radiation of unique sensory cell types with tissue- and stage-specific functions. This diffuse network of distinct sensory cell types could be an adaptive solution for varied sensory tasks experienced in distinct life history stages in Anthozoans.
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Affiliation(s)
- Kyle J McCulloch
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN, 55108, USA
| | - Leslie S Babonis
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA
- Whitney Lab for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA
| | - Alicia Liu
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA , 02138, , USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Christina M Daly
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA , 02138, , USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Mark Q Martindale
- Whitney Lab for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA
| | - Kristen M Koenig
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA , 02138, , USA.
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA.
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14
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Wu Y, Wan X, Zhao D, Chen X, Wang Y, Tang X, Li J, Li S, Sun X, Bi C, Zhang X. AAV-mediated base-editing therapy ameliorates the disease phenotypes in a mouse model of retinitis pigmentosa. Nat Commun 2023; 14:4923. [PMID: 37582961 PMCID: PMC10427680 DOI: 10.1038/s41467-023-40655-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
Base editing technology is an ideal solution for treating pathogenic single-nucleotide variations (SNVs). No gene editing therapy has yet been approved for eye diseases, such as retinitis pigmentosa (RP). Here, we show, in the rd10 mouse model, which carries an SNV identified as an RP-causing mutation in human patients, that subretinal delivery of an optimized dual adeno-associated virus system containing the adenine base editor corrects the pathogenic SNV in the neuroretina with up to 49% efficiency. Light microscopy showed that a thick and robust outer nuclear layer (photoreceptors) was preserved in the treated area compared with the thin, degenerated outer nuclear layer without treatment. Substantial electroretinogram signals were detected in treated rd10 eyes, whereas control treated eyes showed minimal signals. The water maze experiment showed that the treatment substantially improved vision-guided behavior. Together, we construct and validate a translational therapeutic solution for the treatment of RP in humans. Our findings might accelerate the development of base-editing based gene therapies.
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Affiliation(s)
- Yidong Wu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
| | - Xiaoling Wan
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- National Clinical Research Center for Eye Diseases, Shanghai, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China.
| | - Dongdong Zhao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xuxu Chen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Yujie Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xinxin Tang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Ju Li
- College of Life Science, Tianjin Normal University, Tianjin, China
| | - Siwei Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- National Clinical Research Center for Eye Diseases, Shanghai, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China.
| | - Changhao Bi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, China.
| | - Xueli Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, China.
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15
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Sun C, Ruzycki PA, Chen S. Rho enhancers play unexpectedly minor roles in Rhodopsin transcription and rod cell integrity. Sci Rep 2023; 13:12899. [PMID: 37558693 PMCID: PMC10412641 DOI: 10.1038/s41598-023-39979-6] [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: 12/06/2022] [Accepted: 08/02/2023] [Indexed: 08/11/2023] Open
Abstract
Enhancers function with a basal promoter to control the transcription of target genes. Enhancer regulatory activity is often studied using reporter-based transgene assays. However, unmatched results have been reported when selected enhancers are silenced in situ. In this study, using genomic deletion analysis in mice, we investigated the roles of two previously identified enhancers and the promoter of the Rho gene that codes for the visual pigment rhodopsin. The Rho gene is robustly expressed by rod photoreceptors of the retina, and essential for the subcellular structure and visual function of rod photoreceptors. Mutations in RHO cause severe vision loss in humans. We found that each Rho regulatory region can independently mediate local epigenomic changes, but only the promoter is absolutely required for establishing active Rho chromatin configuration and transcription and maintaining the cell integrity and function of rod photoreceptors. To our surprise, two Rho enhancers that enable strong promoter activation in reporter assays are largely dispensable for Rho expression in vivo. Only small and age-dependent impact is detectable when both enhancers are deleted. Our results demonstrate context-dependent roles of enhancers and highlight the importance of studying functions of cis-regulatory regions in the native genomic context.
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Affiliation(s)
- Chi Sun
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, USA
| | - Philip A Ruzycki
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, USA.
- Department of Genetics, Washington University, 660 South Euclid Avenue, MSC 8096-0006-11, Saint Louis, MO, 63110, USA.
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, USA.
- Department of Developmental Biology, Washington University, 660 South Euclid Avenue, MSC 8096-0006-06, Saint Louis, MO, 63110, USA.
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16
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Skiba NP, Lewis TR, Spencer WJ, Castillo CM, Shevchenko A, Arshavsky VY. Absolute Quantification of Photoreceptor Outer Segment Proteins. J Proteome Res 2023; 22:2703-2713. [PMID: 37493966 PMCID: PMC10513726 DOI: 10.1021/acs.jproteome.3c00267] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously determine the abundances of 20 key structural and functional proteins residing in mouse rod outer segments. We computed the absolute number of molecules of each protein residing within an individual outer segment and the molar ratio among all 20 proteins. The molar ratios of proteins comprising three well-characterized constitutive complexes in outer segments differed from the established subunit stoichiometries of these complexes by less than 7%, highlighting the exceptional precision of our quantification. Overall, this study resolves multiple existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.
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Affiliation(s)
- Nikolai P. Skiba
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - Tylor R. Lewis
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - William J. Spencer
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany 01307
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
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17
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Badawi A, Magliyah M, Alabbasi O, AlAbdi L, Alkuraya FS, Schatz P, ALBalawi HB, Mura M. Cone dystrophy associated with autoimmune polyglandular syndrome type 1. Sci Rep 2023; 13:11223. [PMID: 37433860 DOI: 10.1038/s41598-023-38419-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 07/07/2023] [Indexed: 07/13/2023] Open
Abstract
To report the association of autoimmune polyglandular syndrome type 1 (APS1) with cone dystrophy in a large Saudi family. This is a Retrospective chart review and prospective genetic testing and ophthalmic examination of a large multiplex consanguineous family. Genetic testing was performed on 14 family members, seven of whom had detailed ophthalmic examinations. Medical history, ocular history and evaluation, visual field testing, full-field electroretinogram (ERG), and Whole Exome Sequencing (WES) results were analyzed. Three family members were homozygous for c.205_208dupCAGG;p.(Asp70Alafs*148) in AIRE and homozygous for c.481-1G>A in PDE6C. One additional family member was homozygous for only the AIRE variant and another additional family member was homozygous for only the PDE6C variant. All patients with homozygosity for the PDE6C variant had cone dystrophy, and all patients with homozygosity for the AIRE variant had APS1. In addition, two of the family members who were homozygous for the PDE6C and AIRE variants had reduced rod function on ERG. We report the co-inheritance for APS1 and PDE6C-related cone dystrophy, an unusual example of two seemingly independent recessive conditions coinciding within a family. Dual molecular diagnosis must be taken into account by ophthalmologists facing unusual constellations of findings, especially in consanguineous families.
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Affiliation(s)
- Abdulrahman Badawi
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Moustafa Magliyah
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
- Ophthalmology Department, Prince Mohammed Medical City, AlJouf, Saudi Arabia
| | - Omar Alabbasi
- Ophthalmology Department, Almadinah Almonawwarah Hospital, Madinah, Saudi Arabia
| | - Lama AlAbdi
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
- Department of Zoology, Collage of Science, King Saud University, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Patrik Schatz
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
- Department of Ophthalmology, Clinical Sciences, Skane University Hospital, University of Lund, Lund, Sweden
| | - Hani Basher ALBalawi
- Ophthalmology Division, Department of Surgery, Faculty of Medicine, University of Tabuk, Tabuk City, Saudi Arabia.
| | - Marco Mura
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
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18
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Li S, Ma H, Yang F, Ding X. cGMP Signaling in Photoreceptor Degeneration. Int J Mol Sci 2023; 24:11200. [PMID: 37446378 PMCID: PMC10342299 DOI: 10.3390/ijms241311200] [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: 05/23/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Photoreceptors in the retina are highly specialized neurons with photosensitive molecules in the outer segment that transform light into chemical and electrical signals, and these signals are ultimately relayed to the visual cortex in the brain to form vision. Photoreceptors are composed of rods and cones. Rods are responsible for dim light vision, whereas cones are responsible for bright light, color vision, and visual acuity. Photoreceptors undergo progressive degeneration over time in many hereditary and age-related retinal diseases. Despite the remarkable heterogeneity of disease-causing genes, environmental factors, and pathogenesis, the progressive death of rod and cone photoreceptors ultimately leads to loss of vision/blindness. There are currently no treatments available for retinal degeneration. Cyclic guanosine 3', 5'-monophosphate (cGMP) plays a pivotal role in phototransduction. cGMP governs the cyclic nucleotide-gated (CNG) channels on the plasma membrane of the photoreceptor outer segments, thereby regulating membrane potential and signal transmission. By gating the CNG channels, cGMP regulates cellular Ca2+ homeostasis and signal transduction. As a second messenger, cGMP activates the cGMP-dependent protein kinase G (PKG), which regulates numerous targets/cellular events. The dysregulation of cGMP signaling is observed in varieties of photoreceptor/retinal degenerative diseases. Abnormally elevated cGMP signaling interferes with various cellular events, which ultimately leads to photoreceptor degeneration. In line with this, strategies to reduce cellular cGMP signaling result in photoreceptor protection in mouse models of retinal degeneration. The potential mechanisms underlying cGMP signaling-induced photoreceptor degeneration involve the activation of PKG and impaired Ca2+ homeostasis/Ca2+ overload, resulting from overactivation of the CNG channels, as well as the subsequent activation of the downstream cellular stress/death pathways. Thus, targeting the cellular cGMP/PKG signaling and the Ca2+-regulating pathways represents a significant strategy for photoreceptor protection in retinal degenerative diseases.
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Affiliation(s)
| | | | | | - Xiqin Ding
- Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.L.); (H.M.); (F.Y.)
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19
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Laursen WJ, Tang R, Garrity PA. Hunting with heat: thermosensory-driven foraging in mosquitoes, snakes and beetles. J Exp Biol 2023; 226:jeb229658. [PMID: 37382467 PMCID: PMC10323236 DOI: 10.1242/jeb.229658] [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] [Indexed: 06/30/2023]
Abstract
Animals commonly use thermosensation, the detection of temperature and its variation, for defensive purposes: to maintain appropriate body temperature and to avoid tissue damage. However, some animals also use thermosensation to go on the offensive: to hunt for food. The emergence of heat-dependent foraging behavior has been accompanied by the evolution of diverse thermosensory organs of often exquisite thermosensitivity. These organs detect the heat energy emitted from food sources that range from nearby humans to trees burning in a forest kilometers away. Here, we examine the biophysical considerations, anatomical specializations and molecular mechanisms that underlie heat-driven foraging. We focus on three groups of animals that each meet the challenge of detecting heat from potential food sources in different ways: (1) disease-spreading vector mosquitoes, which seek blood meals from warm-bodied hosts at close range, using warming-inhibited thermosensory neurons responsive to conductive and convective heat flow; (2) snakes (vipers, pythons and boas), which seek warm-blooded prey from ten or more centimeters away, using warmth-activated thermosensory neurons housed in an organ specialized to harvest infrared radiation; and (3) fire beetles, which maximize their offspring's feeding opportunities by seeking forest fires from kilometers away, using mechanosensory neurons housed in an organ specialized to convert infrared radiation into mechanosensory stimuli. These examples highlight the diverse ways in which animals exploit the heat emanating from potential food sources, whether this heat reflects ongoing metabolic activity or a recent lightning strike, to secure a nutritious meal for themselves or for their offspring.
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Affiliation(s)
- Willem J. Laursen
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453, USA
| | - Ruocong Tang
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453, USA
| | - Paul A. Garrity
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453, USA
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20
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Lu Y, Tang X, Zhao Y, Jiang T, Zhou J, Wang X, Huang B, Liu L, Deng H, Huang Y, Shi Y. Analysis of electromagnetic response of cells and lipid membranes using a model-free method. Bioelectrochemistry 2023; 152:108444. [PMID: 37146345 DOI: 10.1016/j.bioelechem.2023.108444] [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: 01/28/2023] [Revised: 04/04/2023] [Accepted: 04/10/2023] [Indexed: 05/07/2023]
Abstract
Electromagnetic radiation (EMR) is omnipresent on earth and may interact with the biological systems in diverse manners. But the scope and nature of such interactions remain poorly understood. In this study, we have measured the permittivity of cells and lipid membranes over the EMR frequency range of 20 Hz to 4.35 × 1010 Hz. To identify EMR frequencies that display physically intuitive permittivity features, we have developed a model-free method that relies on a potassium chloride reference solution of direct-current (DC) conductivity equal to that of the target sample. The dielectric constant, which reflects the capacity to store energy, displays a characteristic peak at 105-106 Hz. The dielectric loss factor, which represents EMR absorption, is markedly enhanced at 107-109 Hz. The fine characteristic features are influenced by the size and composition of these membraned structures. Mechanical disruption results in abrogation of these characteristic features. Enhanced energy storage at 105-106 Hz and energy absorption at 107-109 Hz may affect certain membrane activity relevant to cellular function.
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Affiliation(s)
- Yingxian Lu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Xiaping Tang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yanyu Zhao
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Tianyu Jiang
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiayao Zhou
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaofei Wang
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Lingyu Liu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hu Deng
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yujing Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China.
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21
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Ullah M, Rehman AU, Folcher M, Ullah A, Usman F, Rashid A, Khan B, Quinodoz M, Ansar M, Rivolta C. A Novel Intronic Deletion in PDE6B Causes Autosomal Recessive Retinitis Pigmentosa by Interfering with RNA Splicing. Ophthalmic Res 2023; 66:878-884. [PMID: 37094557 DOI: 10.1159/000530800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/17/2023] [Indexed: 04/26/2023]
Abstract
INTRODUCTION Retinitis pigmentosa (RP) is a rare degenerative retinal disease caused by mutations in approximately seventy genes. Currently, despite the availability of large-scale DNA sequencing technologies, ∼30-40% of patients still cannot be diagnosed at the molecular level. In this study, we investigated a novel intronic deletion of PDE6B, encoding the beta subunit of phosphodiesterase 6 in association with recessive RP. METHODS Three unrelated consanguineous families were recruited from the northwestern part of Pakistan. Whole exome sequencing was performed for the proband of each family, and the data were analyzed according to an in-house computer pipeline. Relevant DNA variants in all available members of these families were assessed through Sanger sequencing. A minigene-based splicing assay was also performed. RESULTS The clinical phenotype for all patients was compatible with rod cone degeneration, with the onset during childhood. Whole exome sequencing revealed a homozygous 18 bp intronic deletion (NM_000283.3:c.1921-20_1921-3del) in PDE6B, which co-segregated with disease in 10 affected individuals. In vitro splicing tests showed that this deletion causes aberrant RNA splicing of the gene, leading to the in-frame deletion of 6 codons and, likely, to disease. CONCLUSION Our findings further expand the mutational spectrum of the PDE6B gene.
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Affiliation(s)
- Mukhtar Ullah
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Atta Ur Rehman
- Department of Zoology, Faculty of Biological and Health Sciences, Hazara University Mansehra, Mansehra, Pakistan
| | - Marc Folcher
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Adnan Ullah
- Department of Zoology, Islamia College Peshawar, Peshawar, Pakistan
| | - Faisal Usman
- Department of Biotechnology and Genetic Engineering, Faculty of Biological and Health Sciences, Hazara University Mansehra, Mansehra, Pakistan
| | - Abdur Rashid
- Department of Higher Education, Archives and Libraries Peshawar, Peshawar, Pakistan
| | - Bilal Khan
- Medical Teaching Institution Khyber Teaching Hospital Peshawar, Peshawar, Pakistan
| | - Mathieu Quinodoz
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Muhammad Ansar
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile Des Aveugles, University of Lausanne, Lausanne, Switzerland
- Advanced Molecular Genetics and Genomics Disease Research and Treatment Centre, Dow University of Health Sciences, Karachi, Pakistan
| | - Carlo Rivolta
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
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Karthikeyan R, Davies WI, Gunhaga L. Non-image-forming functional roles of OPN3, OPN4 and OPN5 photopigments. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
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23
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Polyunsaturated Lipids in the Light-Exposed and Prooxidant Retinal Environment. Antioxidants (Basel) 2023; 12:antiox12030617. [PMID: 36978865 PMCID: PMC10044808 DOI: 10.3390/antiox12030617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
The retina is an oxidative stress-prone tissue due to high content of polyunsaturated lipids, exposure to visible light stimuli in the 400–480 nm range, and high oxygen availability provided by choroidal capillaries to support oxidative metabolism. Indeed, lipids’ peroxidation and their conversion into reactive species promoting inflammation have been reported and connected to retinal degenerations. Here, we review recent evidence showing how retinal polyunsaturated lipids, in addition to oxidative stress and damage, may counteract the inflammatory response triggered by blue light-activated carotenoid derivatives, enabling long-term retina operation despite its prooxidant environment. These two aspects of retinal polyunsaturated lipids require tight control over their synthesis to avoid overcoming their protective actions by an increase in lipid peroxidation due to oxidative stress. We review emerging evidence on different transcriptional control mechanisms operating in retinal cells to modulate polyunsaturated lipid synthesis over the life span, from the immature to the ageing retina. Finally, we discuss the antioxidant role of food nutrients such as xanthophylls and carotenoids that have been shown to empower retinal cells’ antioxidant responses and counteract the adverse impact of prooxidant stimuli on sight.
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Li H, Yan Y, Chen J, Shi K, Song C, Ji Y, Jia L, Li J, Qiao Y, Lin Y. Artificial receptor-mediated phototransduction toward protocellular subcompartmentalization and signaling-encoded logic gates. SCIENCE ADVANCES 2023; 9:eade5853. [PMID: 36857444 PMCID: PMC9977178 DOI: 10.1126/sciadv.ade5853] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Engineering artificial cellular systems capable of perceiving and transmitting external signals across membranes to activate downstream targets and coordinate protocellular responses is key to build cell-cell communications and protolife. Here, we report a synthetic photoreceptor-mediated signaling pathway with the integration of light harvesting, photo-to-chemical energy conversion, signal transmission, and amplification in synthetic cells, which ultimately resulted in protocell subcompartmentalization. Key to our design is a ruthenium-bipyridine complex that acts as a membrane-anchored photoreceptor to convert visible light into chemical information and transduce signals across the lipid membrane via flip-flop motion. By coupling receptor-mediated phototransduction with biological recognition and enzymatic cascade reactions, we further develop protocell signaling-encoded Boolean logic gates. Our results illustrate a minimal cell model to mimic the photoreceptor cells that can transduce the energy of light into intracellular responses and pave the way to modular control over the flow of information for complex metabolic and signaling pathways.
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Affiliation(s)
- He Li
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yue Yan
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jing Chen
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Ke Shi
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chuwen Song
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yanglimin Ji
- Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liyan Jia
- Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianming Li
- Research Center of New Energy, Research Institute of Petroleum Exploration and Development (RIPED), PetroChina, Beijing 100083, China
| | - Yan Qiao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiyang Lin
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
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25
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Poria D, Kolesnikov AV, Lee TJ, Salom D, Palczewski K, Kefalov VJ. Investigating the Role of Rhodopsin F45L Mutation in Mouse Rod Photoreceptor Signaling and Survival. eNeuro 2023; 10:ENEURO.0330-22.2023. [PMID: 36823167 PMCID: PMC9997694 DOI: 10.1523/eneuro.0330-22.2023] [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: 08/19/2022] [Revised: 01/16/2023] [Accepted: 01/24/2023] [Indexed: 02/25/2023] Open
Abstract
Rhodopsin is the critical receptor molecule which enables vertebrate rod photoreceptor cells to detect a single photon of light and initiate a cascade of molecular events leading to visual perception. Recently, it has been suggested that the F45L mutation in the transmembrane helix of rhodopsin disrupts its dimerization in vitro To determine whether this mutation of rhodopsin affects its signaling properties in vivo, we generated knock-in mice expressing the rhodopsin F45L mutant. We then examined the function of rods in the mutant mice versus wild-type controls, using in vivo electroretinography and transretinal and single cell suction recordings, combined with morphologic analysis and spectrophotometry. Although we did not evaluate the effect of the F45L mutation on the state of dimerization of the rhodopsin in vivo, our results revealed that F45L-mutant mice exhibit normal retinal morphology, normal rod responses as measured both in vivo and ex vivo, and normal rod dark adaptation. We conclude that the F45L mutation does not affect the signaling properties of rhodopsin in its natural setting.
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Affiliation(s)
- Deepak Poria
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697
| | - Alexander V Kolesnikov
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697
| | - Tae Jun Lee
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO 63110
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697
- Department of Chemistry, University of California, Irvine, CA 92697
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697
| | - Vladimir J Kefalov
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
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Hewitt N, Ma N, Arang N, Martin SA, Prakash A, DiBerto JF, Knight KM, Ghosh S, Olsen RHJ, Roth BL, Gutkind JS, Vaidehi N, Campbell SL, Dohlman HG. Catalytic site mutations confer multiple states of G protein activation. Sci Signal 2023; 16:eabq7842. [PMID: 36787384 PMCID: PMC10021883 DOI: 10.1126/scisignal.abq7842] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 01/31/2023] [Indexed: 02/16/2023]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) that function as molecular switches for cellular growth and metabolism are activated by GTP and inactivated by GTP hydrolysis. In uveal melanoma, a conserved glutamine residue critical for GTP hydrolysis in the G protein α subunit is often mutated in Gαq or Gα11 to either leucine or proline. In contrast, other glutamine mutations or mutations in other Gα subtypes are rare. To uncover the mechanism of the genetic selection and the functional role of this glutamine residue, we analyzed all possible substitutions of this residue in multiple Gα isoforms. Through cell-based measurements of activity, we showed that some mutants were further activated and inactivated by G protein-coupled receptors. Through biochemical, molecular dynamics, and nuclear magnetic resonance-based structural studies, we showed that the Gα mutants were functionally distinct and conformationally diverse, despite their shared inability to hydrolyze GTP. Thus, the catalytic glutamine residue contributes to functions beyond GTP hydrolysis, and these functions include subtype-specific, allosteric modulation of receptor-mediated subunit dissociation. We conclude that G proteins do not function as simple on-off switches. Rather, signaling emerges from an ensemble of active states, a subset of which are favored in disease and may be uniquely responsive to receptor-directed ligands.
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Affiliation(s)
- Natalie Hewitt
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Nadia Arang
- Department of Pharmacology, University of California San Diego, San Diego, CA, 92093, USA
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
| | - Sarah A. Martin
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ajit Prakash
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeffrey F. DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kevin M. Knight
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Soumadwip Ghosh
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
- Current address: Illumina Inc, 5200 Illumina Way, San Diego, CA 92037, USA
| | - Reid H. J. Olsen
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Current address: GPCR Pharmacology, Discovery Biology, Exscientia Ai, Oxford, UK OX4 4GE
| | - Bryan L. Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - J. Silvio Gutkind
- Department of Pharmacology, University of California San Diego, San Diego, CA, 92093, USA
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Sharon L. Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Henrik G. Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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27
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Rodgers J, Hughes S, Lindner M, Allen AE, Ebrahimi AS, Storchi R, Peirson SN, Lucas RJ, Hankins MW. Functional integrity of visual coding following advanced photoreceptor degeneration. Curr Biol 2023; 33:474-486.e5. [PMID: 36630957 DOI: 10.1016/j.cub.2022.12.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 11/01/2022] [Accepted: 12/09/2022] [Indexed: 01/11/2023]
Abstract
Photoreceptor degeneration sufficient to produce severe visual loss often spares the inner retina. This raises hope for vision restoration treatments using optogenetics or electrical stimulation, which generate a replacement light input signal in surviving neurons. The success of these approaches is dependent on the capacity of surviving circuits of the visual system to generate and propagate an appropriate visual code in the face of neuroanatomical remodeling. To determine whether retinally degenerate animals possess this capacity, we generated a transgenic mouse model expressing the optogenetic actuator ReaChR in ON bipolar cells (second-order neurons in the visual projection). After crossing this with the rd1 model of photoreceptor degeneration, we compared ReaChR-derived responses with photoreceptor-driven responses in wild-type (WT) mice at the level of retinal ganglion cells and the visual thalamus. The ReaChR-driven responses in rd1 animals showed low photosensitivity, but in other respects generated a visual code that was very similar to the WT. ReaChR rd1 responses had high trial-to-trial reproducibility and showed sensitivity normalization to code contrast across background intensities. At the single unit level, ReaChR-derived responses exhibited broadly similar variations in response polarity, contrast sensitivity, and temporal frequency tuning as the WT. Units from the WT and ReaChR rd1 mice clustered together when subjected to unsupervised community detection based on stimulus-response properties. Our data reveal an impressive ability for surviving circuitry to recreate a rich visual code following advanced retinal degeneration and are promising for regenerative medicine in the central nervous system.
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Affiliation(s)
- Jessica Rodgers
- Faculty of Biology, Medicine & Health, University of Manchester, Upper Brook Street, Manchester M13 9PT, UK
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Moritz Lindner
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, Marburg 35037, Germany
| | - Annette E Allen
- Faculty of Biology, Medicine & Health, University of Manchester, Upper Brook Street, Manchester M13 9PT, UK
| | - Aghileh S Ebrahimi
- Faculty of Biology, Medicine & Health, University of Manchester, Upper Brook Street, Manchester M13 9PT, UK
| | - Riccardo Storchi
- Faculty of Biology, Medicine & Health, University of Manchester, Upper Brook Street, Manchester M13 9PT, UK
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Robert J Lucas
- Faculty of Biology, Medicine & Health, University of Manchester, Upper Brook Street, Manchester M13 9PT, UK.
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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28
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Gulati S, Palczewski K. Structural view of G protein-coupled receptor signaling in the retinal rod outer segment. Trends Biochem Sci 2023; 48:172-186. [PMID: 36163145 PMCID: PMC9868064 DOI: 10.1016/j.tibs.2022.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 01/26/2023]
Abstract
Visual phototransduction is the most extensively studied G protein-coupled receptor (GPCR) signaling pathway because of its quantifiable stimulus, non-redundancy of genes, and immense importance in vision. We summarize recent discoveries that have advanced our understanding of rod outer segment (ROS) morphology and the pathological basis of retinal diseases. We have combined recently published cryo-electron tomography (cryo-ET) data on the ROS with structural knowledge on individual proteins to define the precise spatial limitations under which phototransduction occurs. Although hypothetical, the reconstruction of the rod phototransduction system highlights the potential roles of phosphodiesterase 6 (PDE6) and guanylate cyclases (GCs) in maintaining the spacing between ROS discs, suggesting a plausible mechanism by which intrinsic optical signals are generated in the retina.
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Affiliation(s)
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, Center for Translational Vision Research, Department of Physiology and Biophysics, Department of Chemistry, Molecular Biology, and Biochemistry, University of California Irvine, 850 Health Sciences Road, Irvine, CA 92697-4375, USA.
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29
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Ono Y, Kawakami K, Nakamura G, Ishida S, Aoki J, Inoue A. Generation of Gαi knock-out HEK293 cells illuminates Gαi-coupling diversity of GPCRs. Commun Biol 2023; 6:112. [PMID: 36709222 PMCID: PMC9884212 DOI: 10.1038/s42003-023-04465-2] [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: 08/03/2022] [Accepted: 01/11/2023] [Indexed: 01/29/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are pivotal cell membrane proteins that sense extracellular molecules and activate cellular responses. The G-protein α subunit i (Gαi) family represents the most common GPCR-coupling partner and consists of eight subunits with distinct signaling properties. However, analyzing the coupling pattern has been challenging owing to endogenous expression of the Gαi subunits in virtually all cell lines. Here, we generate a HEK293 cell line lacking all Gαi subunits, which enables the measurement of GPCR-Gαi coupling upon transient re-expression of a specific Gαi subunit. We profile Gαi-coupling selectivity across 11 GPCRs by measuring ligand-induced inhibitory activity for cAMP accumulation. The coupling profiles are then classified into three clusters, representing those preferentially coupled to Gαz, those to Gαo, and those with unapparent selectivity. These results indicate that individual Gαi-coupled GPCRs fine-tune Gαi signaling by exerting coupling preference at the Gαi-subunit level.
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Affiliation(s)
- Yuki Ono
- grid.69566.3a0000 0001 2248 6943Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578 Japan
| | - Kouki Kawakami
- grid.69566.3a0000 0001 2248 6943Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578 Japan
| | - Gaku Nakamura
- grid.69566.3a0000 0001 2248 6943Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578 Japan
| | - Satoru Ishida
- grid.69566.3a0000 0001 2248 6943Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578 Japan
| | - Junken Aoki
- grid.26999.3d0000 0001 2151 536XDepartment of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 Japan
| | - Asuka Inoue
- grid.69566.3a0000 0001 2248 6943Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578 Japan
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30
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Mercau ME, Akalu YT, Mazzoni F, Gyimesi G, Alberto EJ, Kong Y, Hafler BP, Finnemann SC, Rothlin CV, Ghosh S. Inflammation of the retinal pigment epithelium drives early-onset photoreceptor degeneration in Mertk-associated retinitis pigmentosa. SCIENCE ADVANCES 2023; 9:eade9459. [PMID: 36662852 PMCID: PMC9858494 DOI: 10.1126/sciadv.ade9459] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/19/2022] [Indexed: 05/17/2023]
Abstract
Severe, early-onset photoreceptor (PR) degeneration associated with MERTK mutations is thought to result from failed phagocytosis by retinal pigment epithelium (RPE). Notwithstanding, the severity and onset of PR degeneration in mouse models of Mertk ablation are determined by the hypomorphic expression or the loss of the Mertk paralog Tyro3. Here, we find that loss of Mertk and reduced expression/loss of Tyro3 led to RPE inflammation even before eye-opening. Incipient RPE inflammation cascaded to involve microglia activation and PR degeneration with monocyte infiltration. Inhibition of RPE inflammation with the JAK1/2 inhibitor ruxolitinib mitigated PR degeneration in Mertk-/- mice. Neither inflammation nor severe, early-onset PR degeneration was observed in mice with defective phagocytosis alone. Thus, inflammation drives severe, early-onset PR degeneration-associated with Mertk loss of function.
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Affiliation(s)
- Maria E. Mercau
- Department of Immunobiology, School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Yemsratch T. Akalu
- Department of Immunobiology, School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Francesca Mazzoni
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA
| | - Gavin Gyimesi
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA
| | - Emily J. Alberto
- Department of Immunobiology, School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Yong Kong
- Department of Molecular Biophysics and Biochemistry, W. M. Keck Foundation Biotechnology Resource Laboratory, School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Brian P. Hafler
- Department of Ophthalmology, School of Medicine, Yale University, New Haven, CT 06520, USA
- Department of Pathology, School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Silvia C. Finnemann
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA
| | - Carla V. Rothlin
- Department of Immunobiology, School of Medicine, Yale University, New Haven, CT 06520, USA
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Sourav Ghosh
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT 06520, USA
- Department of Neurology, School of Medicine, Yale University, New Haven, CT 06520, USA
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31
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Skiba NP, Lewis TR, Spencer WJ, Castillo CM, Shevchenko A, Arshavsky VY. Absolute quantification of photoreceptor outer segment proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524794. [PMID: 36711880 PMCID: PMC9882265 DOI: 10.1101/2023.01.19.524794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously measure the outer segment content of twenty key structural and functional proteins. We determined the molar ratio amongst all twenty proteins as well as the number of molecules of each protein residing within an outer segment. To assess the precision of this quantification, we took advantage of the fact that seven of these proteins exist within three constitutive complexes of well-established subunit stoichiometries. Remarkably, our measurements differed from these stoichiometries by less than 7%, highlighting the exceptional precision of our quantification. This allowed us to resolve the existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.
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32
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Kilgas S, Ramadan K. Inhibitors of the ATPase p97/VCP: From basic research to clinical applications. Cell Chem Biol 2023; 30:3-21. [PMID: 36640759 DOI: 10.1016/j.chembiol.2022.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/13/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023]
Abstract
Protein homeostasis deficiencies underlie various cancers and neurodegenerative diseases. The ubiquitin-proteasome system (UPS) and autophagy are responsible for most of the protein degradation in mammalian cells and, therefore, represent attractive targets for cancer therapy and that of neurodegenerative diseases. The ATPase p97, also known as VCP, is a central component of the UPS that extracts and disassembles its substrates from various cellular locations and also regulates different steps in autophagy. Several UPS- and autophagy-targeting drugs are in clinical trials. In this review, we focus on the development of various p97 inhibitors, including the ATPase inhibitors CB-5083 and CB-5339, which reached clinical trials by demonstrating effective anti-tumor activity across various tumor models, providing an effective alternative to targeting protein degradation for cancer therapy. Here, we provide an overview of how different p97 inhibitors have evolved over time both as basic research tools and effective UPS-targeting cancer therapies in the clinic.
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Affiliation(s)
- Susan Kilgas
- Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
| | - Kristijan Ramadan
- Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
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Dauchy RT, Blask DE. Vivarium Lighting as an Important Extrinsic Factor Influencing Animal-based Research. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2023; 62:3-25. [PMID: 36755210 PMCID: PMC9936857 DOI: 10.30802/aalas-jaalas-23-000003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 01/22/2023]
Abstract
Light is an extrinsic factor that exerts widespread influence on the regulation of circadian, physiologic, hormonal, metabolic, and behavioral systems of all animals, including those used in research. These wide-ranging biologic effects of light are mediated by distinct photoreceptors, the melanopsin-containing intrinsically photosensitive retinal ganglion cells of the nonvisual system, which interact with the rods and cones of the conventional visual system. Here, we review the nature of light and circadian rhythms, current industry practices and standards, and our present understanding of the neurophysiology of the visual and nonvisual systems. We also consider the implications of this extrinsic factor for vivarium measurement, production, and technological application of light, and provide simple recommendations on artificial lighting for use by regulatory authorities, lighting manufacturers, designers, engineers, researchers, and research animal care staff that ensure best practices for optimizing animal health and wellbeing and, ultimately, improving scientific outcomes.
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Key Words
- blad, blue-enriched led light at daytime
- clock, circadian locomotor output kaput
- cct, correlated color temperature
- cwf, cool white fluorescent
- iprgc, intrinsically photosensitive retinal ganglion cell
- hiomt, hydroxyindole-o-methyltransferase
- lan, light at night
- led, light-emitting diode
- plr, pupillary light reflex
- scn, suprachiasmatic nuclei
- spd, spectral power distribution
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Affiliation(s)
- Robert T Dauchy
- Department of Structural and Cellular Biology, Laboratory of Chrono-Neuroendocrine Oncology, Tulane University School of Medicine, New Orleans, Louisiana
| | - David E Blask
- Department of Structural and Cellular Biology, Laboratory of Chrono-Neuroendocrine Oncology, Tulane University School of Medicine, New Orleans, Louisiana
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Nicoletti M, Luchetti N, Chiodo L, Loppini A, Folli V, Ruocco G, Filippi S. Modeling of olfactory transduction in AWC ON neuron via coupled electrical-calcium dynamics. Biomol Concepts 2023; 14:bmc-2022-0035. [PMID: 37574865 DOI: 10.1515/bmc-2022-0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/28/2023] [Indexed: 08/15/2023] Open
Abstract
Amphid wing "C" (AWC) neurons are among the most important and studied neurons of the nematode Caenorhabditis elegans. In this work, we unify the existing electrical and intracellular calcium dynamics descriptions to obtain a biophysically accurate model of olfactory transduction in AWCON neurons. We study the membrane voltage and the intracellular calcium dynamics at different exposure times and odorant concentrations to grasp a complete picture of AWCON functioning. Moreover, we investigate the complex cascade of biochemical processes that allow AWC activation upon odor removal. We analyze the behavior of the different components of the models and, by suppressing them selectively, we extrapolate their contribution to the overall neuron response and study the resilience of the dynamical system. Our results are all in agreement with the available experimental data. Therefore, we provide an accurate mathematical and biophysical model for studying olfactory signal processing in C. elegans.
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Affiliation(s)
- Martina Nicoletti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Nicole Luchetti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Letizia Chiodo
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
| | | | - Viola Folli
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
- D-tails s.r.l., Via di Torre Rossa 66, 00165, Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Simonetta Filippi
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), Florence, Italy
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VISUAL OPSINS: PHYSIOLOGICAL ALTERATION PROMOTED BY LED LIGHT. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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36
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Eilertsen M, Dolan DWP, Bolton CM, Karlsen R, Davies WIL, Edvardsen RB, Furmanek T, Sveier H, Migaud H, Helvik JV. Photoreception and transcriptomic response to light during early development of a teleost with a life cycle tightly controlled by seasonal changes in photoperiod. PLoS Genet 2022; 18:e1010529. [PMID: 36508414 PMCID: PMC9744326 DOI: 10.1371/journal.pgen.1010529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022] Open
Abstract
Light cues vary along the axis of periodicity, intensity and spectrum and perception of light is dependent on the photoreceptive capacity encoded within the genome and the opsins expressed. A global approach was taken to analyze the photoreceptive capacity and the effect of differing light conditions on a developing teleost prior to first feeding. The transcriptomes of embryos and alevins of Atlantic salmon (Salmo salar) exposed to different light conditions were analyzed, including a developmental series and a circadian profile. The results showed that genes mediating nonvisual photoreception are present prior to hatching when the retina is poorly differentiated. The clock genes were expressed early, but the circadian profile showed that only two clock genes were significantly cycling before first feeding. Few genes were differentially expressed between day and night within a light condition; however, many genes were significantly different between light conditions, indicating that light environment has an impact on the transcriptome during early development. Comparing the transcriptome data from constant conditions to periodicity of white light or different colors revealed overrepresentation of genes related to photoreception, eye development, muscle contraction, degradation of metabolites and cell cycle among others, and in constant light, several clock genes were upregulated. In constant white light and periodicity of green light, genes associated with DNA replication, chromatin remodeling, cell division and DNA repair were downregulated. The study implies a direct influence of light conditions on the transcriptome profile at early developmental stages, by a complex photoreceptive system where few clock genes are cycling.
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Affiliation(s)
- Mariann Eilertsen
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- * E-mail: (ME); (JVH)
| | | | - Charlotte M. Bolton
- Institute of Aquaculture, University of Stirling, Stirling, Scotland, United Kingdom
| | - Rita Karlsen
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Wayne I. L. Davies
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Melbourne, Australia
| | | | | | | | - Herve Migaud
- Institute of Aquaculture, University of Stirling, Stirling, Scotland, United Kingdom
| | - Jon Vidar Helvik
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- * E-mail: (ME); (JVH)
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Pasmanter N, Petersen-Jones SM. Characterization of scotopic and mesopic rod signaling pathways in dogs using the On-Off electroretinogram. BMC Vet Res 2022; 18:422. [PMID: 36463174 PMCID: PMC9719241 DOI: 10.1186/s12917-022-03505-z] [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: 09/18/2021] [Accepted: 11/07/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The On-Off, or long flash, full field electroretinogram (ERG) separates retinal responses to flash onset and offset. Depending on degree of dark-adaptation and stimulus strength the On and Off ERG can be shaped by rod and cone photoreceptors and postreceptoral cells, including ON and OFF bipolar cells. Interspecies differences have been shown, with predominantly positive Off-response in humans and other primates and a negative Off-response in rodents and dogs. However, the rod signaling pathways that contribute to these differential responses have not been characterized. In this study, we designed a long flash protocol in the dog that varied in background luminance and stimulus strength allowing for some rod components to be present to better characterize how rod pathways vary from scotopic to mesopic conditions. RESULTS With low background light the rod a-wave remains while the b-wave is significantly reduced resulting in a predominantly negative waveform in mesopic conditions. Through modeling and subtraction of the rod-driven response, we show that rod bipolar cells saturate with dimmer backgrounds than rod photoreceptors, resulting in rod hyperpolarization contributing to a large underlying negativity with mesopic backgrounds. CONCLUSIONS Reduction in rod bipolar cell responses in mesopic conditions prior to suppression of rod photoreceptor responses may reflect the changes in signaling pathway of rod-driven responses needed to extend the range of lighting conditions over which the retina functions.
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Affiliation(s)
- Nate Pasmanter
- grid.17088.360000 0001 2150 1785Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D208 East Lansing, MI USA
| | - Simon M. Petersen-Jones
- grid.17088.360000 0001 2150 1785Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D208 East Lansing, MI USA
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Pasquaré SJ, Chamorro-Aguirre E, Gaveglio VL. The endocannabinoid system in the visual process. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2022. [DOI: 10.1016/j.jpap.2022.100159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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39
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Das A, Imanishi Y. Drug Discovery Strategies for Inherited Retinal Degenerations. BIOLOGY 2022; 11:1338. [PMID: 36138817 PMCID: PMC9495580 DOI: 10.3390/biology11091338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 12/03/2022]
Abstract
Inherited retinal degeneration is a group of blinding disorders afflicting more than 1 in 4000 worldwide. These disorders frequently cause the death of photoreceptor cells or retinal ganglion cells. In a subset of these disorders, photoreceptor cell death is a secondary consequence of retinal pigment epithelial cell dysfunction or degeneration. This manuscript reviews current efforts in identifying targets and developing small molecule-based therapies for these devastating neuronal degenerations, for which no cures exist. Photoreceptors and retinal ganglion cells are metabolically demanding owing to their unique structures and functional properties. Modulations of metabolic pathways, which are disrupted in most inherited retinal degenerations, serve as promising therapeutic strategies. In monogenic disorders, great insights were previously obtained regarding targets associated with the defective pathways, including phototransduction, visual cycle, and mitophagy. In addition to these target-based drug discoveries, we will discuss how phenotypic screening can be harnessed to discover beneficial molecules without prior knowledge of their mechanisms of action. Because of major anatomical and biological differences, it has frequently been challenging to model human inherited retinal degeneration conditions using small animals such as rodents. Recent advances in stem cell-based techniques are opening new avenues to obtain pure populations of human retinal ganglion cells and retinal organoids with photoreceptor cells. We will discuss concurrent ideas of utilizing stem-cell-based disease models for drug discovery and preclinical development.
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Affiliation(s)
- Arupratan Das
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yoshikazu Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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40
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Ziaka K, van der Spuy J. The Role of Hsp90 in Retinal Proteostasis and Disease. Biomolecules 2022; 12:biom12070978. [PMID: 35883534 PMCID: PMC9313453 DOI: 10.3390/biom12070978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/24/2022] Open
Abstract
Photoreceptors are sensitive neuronal cells with great metabolic demands, as they are responsible for carrying out visual phototransduction, a complex and multistep process that requires the exquisite coordination of a large number of signalling protein components. Therefore, the viability of photoreceptors relies on mechanisms that ensure a well-balanced and functional proteome that maintains the protein homeostasis, or proteostasis, of the cell. This review explores how the different isoforms of Hsp90, including the cytosolic Hsp90α/β, the mitochondrial TRAP1, and the ER-specific GRP94, are involved in the different proteostatic mechanisms of photoreceptors, and elaborates on Hsp90 function when retinal homeostasis is disturbed. In addition, several studies have shown that chemical manipulation of Hsp90 has significant consequences, both in healthy and degenerating retinae, and this can be partially attributed to the fact that Hsp90 interacts with important photoreceptor-associated client proteins. Here, the interaction of Hsp90 with the retina-specific client proteins PDE6 and GRK1 will be further discussed, providing additional insights for the role of Hsp90 in retinal disease.
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Gene-independent therapeutic interventions to maintain and restore light sensitivity in degenerating photoreceptors. Prog Retin Eye Res 2022; 90:101065. [PMID: 35562270 DOI: 10.1016/j.preteyeres.2022.101065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 12/14/2022]
Abstract
Neurodegenerative retinal diseases are a prime cause of blindness in industrialized countries. In many cases, there are no therapeutic treatments, although they are essential to improve patients' quality of life. A set of disease-causing genes, which primarily affect photoreceptors, has already been identified and is of major interest for developing gene therapies. Nevertheless, depending on the nature and the state of the disease, gene-independent strategies are needed. Various strategies to halt disease progression or maintain function of the retina are under research. These therapeutic interventions include neuroprotection, direct reprogramming of affected photoreceptors, the application of non-coding RNAs, the generation of artificial photoreceptors by optogenetics and cell replacement strategies. During recent years, major breakthroughs have been made such as the first optogenetic application to a blind patient whose visual function partially recovered by targeting retinal ganglion cells. Also, RPE cell transplantation therapies are under clinical investigation and show great promise to improve visual function in blind patients. These cells are generated from human stem cells. Similar therapies for replacing photoreceptors are extensively tested in pre-clinical models. This marks just the start of promising new cures taking advantage of developments in the areas of genetic engineering, optogenetics, and stem-cell research. In this review, we present the recent therapeutic advances of gene-independent approaches that are currently under clinical evaluation. Our main focus is on photoreceptors as these sensory cells are highly vulnerable to degenerative diseases, and are crucial for light detection.
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Nagata K, Hishikawa D, Sagara H, Saito M, Watanabe S, Shimizu T, Shindou H. Lysophosphatidylcholine acyltransferase 1 controls mitochondrial reactive oxygen species generation and survival of retinal photoreceptor cells. J Biol Chem 2022; 298:101958. [PMID: 35452679 PMCID: PMC9136105 DOI: 10.1016/j.jbc.2022.101958] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/31/2022] [Accepted: 04/15/2022] [Indexed: 12/19/2022] Open
Abstract
Due to their high energy demands and characteristic morphology, retinal photoreceptor cells require a specialized lipid metabolism for survival and function. Accordingly, dysregulation of lipid metabolism leads to the photoreceptor cell death and retinal degeneration. Mice bearing a frameshift mutation in the gene encoding lysophosphatidylcholine acyltransferase 1 (Lpcat1), which produces saturated phosphatidylcholine (PC) composed of two saturated fatty acids, has been reported to cause spontaneous retinal degeneration in mice; however, the mechanism by which this mutation affects degeneration is unclear. In this study, we performed a detailed characterization of LPCAT1 in the retina and found that genetic deletion of Lpcat1 induces light-independent and photoreceptor-specific apoptosis in mice. Lipidomic analyses of the retina and isolated photoreceptor outer segment (OS) suggested that loss of Lpcat1 not only decreased saturated PC production but also affected membrane lipid composition, presumably by altering saturated fatty acyl-CoA availability. Furthermore, we demonstrated that Lpcat1 deletion led to increased mitochondrial reactive oxygen species levels in photoreceptor cells, but not in other retinal cells, and did not affect the OS structure or trafficking of OS-localized proteins. These results suggest that the LPCAT1-dependent production of saturated PC plays critical roles in photoreceptor maturation. Our findings highlight the therapeutic potential of saturated fatty acid metabolism in photoreceptor cell degeneration-related retinal diseases.
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Affiliation(s)
- Katsuyuki Nagata
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
| | - Daisuke Hishikawa
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
| | - Hiroshi Sagara
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan
| | - Masamichi Saito
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan
| | - Takao Shimizu
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan; Department of Lipid Science, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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The Molecular Mechanism of Retina Light Injury Focusing on Damage from Short Wavelength Light. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:8482149. [PMID: 35498134 PMCID: PMC9042598 DOI: 10.1155/2022/8482149] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/31/2022] [Indexed: 12/30/2022]
Abstract
Natural visible light is an electromagnetic wave composed of a spectrum of monochromatic wavelengths, each with a characteristic color. Photons are the basic units of light, and their wavelength correlates to the energy of light; short-wavelength photons carry high energy. The retina is a fragile neuronal tissue that senses light and generates visual signals conducted to the brain. However, excessive and intensive light exposure will cause retinal light damage. Within the visible spectrum, short-wavelength light, such as blue light, carries higher energy, and thus the retinal injury, is more significant when exposed to these wavelengths. The damage mechanism triggered by different short-wavelength light varies due to photons carrying different energy and being absorbed by different photosensitive molecules in the retinal neurons. However, photooxidation might be a common molecular step to initiate cell death. Herein, we summarize the historical understanding of light, the key molecular steps related to retinal light injury, and the death pathways of photoreceptors to further decipher the molecular mechanism of retinal light injury and explore potential neuroprotective strategies.
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McCulloch KJ, Macias-Muñoz A, Mortazavi A, Briscoe AD. Multiple mechanisms of photoreceptor spectral tuning in Heliconius butterflies. Mol Biol Evol 2022; 39:6555095. [PMID: 35348742 PMCID: PMC9048915 DOI: 10.1093/molbev/msac067] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The evolution of color vision is often studied through the lens of receptor gain relative to an ancestor with fewer spectral classes of photoreceptor. For instance, in Heliconius butterflies, a genus-specific UVRh opsin duplication led to the evolution of UV color discrimination in Heliconius erato females, a rare trait among butterflies. However, color vision evolution is not well understood in the context of loss. In Heliconius melpomene and Heliconius ismenius lineages, the UV2 receptor subtype has been lost, which limits female color vision in shorter wavelengths. Here, we compare the visual systems of butterflies that have either retained or lost the UV2 photoreceptor using intracellular recordings, ATAC-seq, and antibody staining. We identify several ways these butterflies modulate their color vision. In H. melpomene, chromatin reorganization has downregulated an otherwise intact UVRh2 gene, whereas in H. ismenius, pseudogenization has led to the truncation of UVRh2. In species that lack the UV2 receptor, the peak sensitivity of the remaining UV1 photoreceptor cell is shifted to longer wavelengths. Across Heliconius, we identify the widespread use of filtering pigments and co-expression of two opsins in the same photoreceptor cells. Multiple mechanisms of spectral tuning, including the molecular evolution of blue opsins, have led to the divergence of receptor sensitivities between species. The diversity of photoreceptor and ommatidial subtypes between species suggests that Heliconius visual systems are under varying selection pressures for color discrimination. Modulating the wavelengths of peak sensitivities of both the blue- and remaining UV-sensitive photoreceptor cells suggests that Heliconius species may have compensated for UV receptor loss.
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Affiliation(s)
- Kyle J McCulloch
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA.,Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA
| | - Aide Macias-Muñoz
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA.,Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara CA 93106, USA.,Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Adriana D Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA
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Nazlamova L, Cassidy EJ, Sowden JC, Lotery A, Lakowski J. Generation of a Cone Photoreceptor-specific GNGT2 Reporter Line in Human Pluripotent Stem Cells. Stem Cells 2022; 40:190-203. [PMID: 35293574 DOI: 10.1093/stmcls/sxab015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/23/2021] [Indexed: 11/14/2022]
Abstract
Fluorescent reporter lines generated in human pluripotent stem cells are a highly useful tool to track, isolate, and analyze cell types and lineages in live cultures. Here, we generate the first human cone photoreceptor reporter cell line by CRISPR/Cas9 genome editing of a human embryonic stem cell (hESC) line to tag both alleles of the Guanine nucleotide-binding protein subunit gamma-T2 (GNGT2) gene with a mCherry reporter cassette. Three-dimensional optic vesicle-like structures were produced to verify reporter fidelity and track cones throughout their development in culture. The GNGT2-T2A-mCherry hESC line faithfully and robustly labels GNGT2-expressing cones throughout the entirety of their differentiation in vitro, recapitulating normal fetal expression of this gene. Our observations indicate that human cones undergo significant migratory activity during the course of differentiation in vitro. Consistent with this, our analysis of human fetal retinae from different stages of development finds positional differences of the cone population depending on their state of maturation. This novel reporter line will provide a useful tool for investigating human cone development and disease.
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Affiliation(s)
- Liliya Nazlamova
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Emma-Jane Cassidy
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - Jane C Sowden
- UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Andrew Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Jörn Lakowski
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
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46
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Angueyra JM, Baudin J, Schwartz GW, Rieke F. Predicting and Manipulating Cone Responses to Naturalistic Inputs. J Neurosci 2022; 42:1254-1274. [PMID: 34949692 PMCID: PMC8883858 DOI: 10.1523/jneurosci.0793-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 11/06/2021] [Accepted: 12/03/2021] [Indexed: 11/21/2022] Open
Abstract
Primates explore their visual environment by making frequent saccades, discrete and ballistic eye movements that direct the fovea to specific regions of interest. Saccades produce large and rapid changes in input. The magnitude of these changes and the limited signaling range of visual neurons mean that effective encoding requires rapid adaptation. Here, we explore how macaque cone photoreceptors maintain sensitivity under these conditions. Adaptation makes cone responses to naturalistic stimuli highly nonlinear and dependent on stimulus history. Such responses cannot be explained by linear or linear-nonlinear models but are well explained by a biophysical model of phototransduction based on well-established biochemical interactions. The resulting model can predict cone responses to a broad range of stimuli and enables the design of stimuli that elicit specific (e.g., linear) cone photocurrents. These advances will provide a foundation for investigating the contributions of cone phototransduction and post-transduction processing to visual function.SIGNIFICANCE STATEMENT We know a great deal about adaptational mechanisms that adjust sensitivity to slow changes in visual inputs such as the rising or setting sun. We know much less about the rapid adaptational mechanisms that are essential for maintaining sensitivity as gaze shifts around a single visual scene. We characterize how phototransduction in cone photoreceptors adapts to rapid changes in input similar to those encountered during natural vision. We incorporate these measurements into a quantitative model that can predict cone responses across a broad range of stimuli. This model not only shows how cone phototransduction aids the encoding of natural inputs but also provides a tool to identify the role of the cone responses in shaping those of downstream visual neurons.
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Affiliation(s)
- Juan M Angueyra
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195
- National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Jacob Baudin
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195
| | - Gregory W Schwartz
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60511
| | - Fred Rieke
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195
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47
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Escobedo SE, Stanhope SC, Dong Z, Weake VM. Aging and Light Stress Result in Overlapping and Unique Gene Expression Changes in Photoreceptors. Genes (Basel) 2022; 13:264. [PMID: 35205309 PMCID: PMC8872477 DOI: 10.3390/genes13020264] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 11/20/2022] Open
Abstract
Advanced age is one of the leading risk factors for vision loss and eye disease. Photoreceptors are the primary sensory neurons of the eye. The extended photoreceptor cell lifespan, in addition to its high metabolic needs due to phototransduction, makes it critical for these neurons to continually respond to the stresses associated with aging by mounting an appropriate gene expression response. Here, we sought to untangle the more general neuronal age-dependent transcriptional signature of photoreceptors with that induced by light stress. To do this, we aged flies or exposed them to various durations of blue light, followed by photoreceptor nuclei-specific transcriptome profiling. Using this approach, we identified genes that are both common and uniquely regulated by aging and light induced stress. Whereas both age and blue light induce expression of DNA repair genes and a neuronal-specific signature of death, both conditions result in downregulation of phototransduction. Interestingly, blue light uniquely induced genes that directly counteract the overactivation of the phototransduction signaling cascade. Lastly, unique gene expression changes in aging photoreceptors included the downregulation of genes involved in membrane potential homeostasis and mitochondrial function, as well as the upregulation of immune response genes. We propose that light stress contributes to the aging transcriptome of photoreceptors, but that there are also other environmental or intrinsic factors involved in age-associated photoreceptor gene expression signatures.
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Affiliation(s)
- Spencer E. Escobedo
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA; (S.E.E.); (S.C.S.); (Z.D.)
| | - Sarah C. Stanhope
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA; (S.E.E.); (S.C.S.); (Z.D.)
| | - Ziyu Dong
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA; (S.E.E.); (S.C.S.); (Z.D.)
| | - Vikki M. Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA; (S.E.E.); (S.C.S.); (Z.D.)
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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Kawamura S, Tachibanaki S. Molecular basis of rod and cone differences. Prog Retin Eye Res 2021; 90:101040. [PMID: 34974196 DOI: 10.1016/j.preteyeres.2021.101040] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 12/15/2022]
Abstract
In the vertebrate retina, rods and cones both detect light, but they are different in functional aspects such as light sensitivity and time resolution, for example, and in some of cell biological aspects. For functional aspects, both photoreceptors are known to share a common mechanism, phototransduction cascade, consisting of a series of enzyme reactions to convert a photon-capture signal to an electrical signal. To understand the mechanisms of the functional differences between rods and cones at the molecular level, we compared biochemically each of the reactions in the phototransduction cascade between rods and cones using the cells isolated and purified from carp retina. Although proteins in the cascade are functionally similar between rods and cones, their activities together with their expression levels are mostly different between these photoreceptors. In general, reactions to generate a response are slightly less effective, as a total, in cones than in rods, but each of the reactions for termination and recovery of a response are much more effective in cones. These findings explain lower light sensitivity and briefer light responses in cones than in rods. In addition, our considerations suggest that a Ca2+-binding protein, S-modulin or recoverin, has a currently unnoticed role in shaping light responses. With comparison of the expression levels of proteins and/or mRNAs using purified cells, several proteins were found to be specifically or predominantly expressed in cones. These proteins would be of interest for future studies on the difference between rods and cones.
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Affiliation(s)
- Satoru Kawamura
- Graduate School of Frontier Biosciences, Osaka University, Yamada-oka 1-3, Suita, Osaka, 565-0871, Japan; Department of Biological Sciences, Graduate School of Science, Osaka University, Yamada-oka 1-3, Suita, Osaka, 565-0871, Japan.
| | - Shuji Tachibanaki
- Graduate School of Frontier Biosciences, Osaka University, Yamada-oka 1-3, Suita, Osaka, 565-0871, Japan; Department of Biological Sciences, Graduate School of Science, Osaka University, Yamada-oka 1-3, Suita, Osaka, 565-0871, Japan.
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49
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Trifonov L, Rothstein A, Korshin EE, Viskind O, Afri M, Leitus G, Palczewski K, Gruzman A. Straightforward Access to Terminally Disubstituted Electron‐Deficient Alkylidene Cyclopent‐2‐en‐4‐ones through Olefination with α‐Carbonyl and α‐Cyano Secondary Alkyl Sulfones. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lena Trifonov
- Department of Chemistry, Bar-Ilan University Max and Anna Webb St. Ramat-Gan 5290002 Israel
| | - Ayelet Rothstein
- Department of Chemistry, Bar-Ilan University Max and Anna Webb St. Ramat-Gan 5290002 Israel
| | - Edward E. Korshin
- Department of Chemistry, Bar-Ilan University Max and Anna Webb St. Ramat-Gan 5290002 Israel
| | - Olga Viskind
- Department of Chemistry, Bar-Ilan University Max and Anna Webb St. Ramat-Gan 5290002 Israel
| | - Michal Afri
- Department of Chemistry, Bar-Ilan University Max and Anna Webb St. Ramat-Gan 5290002 Israel
| | - Gregory Leitus
- Department of Chemical Research Support the Weizmann Institute of Science Rehovot 76100 Israel
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute Department of Ophthalmology and Departments of Physiology and Biophysics and Chemistry and Molecular Biology and Biochemistry, University of California Irvine CA 92697 USA
| | - Arie Gruzman
- Department of Chemistry, Bar-Ilan University Max and Anna Webb St. Ramat-Gan 5290002 Israel
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50
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Phototransduction in Anuran Green Rods: Origins of Extra-Sensitivity. Int J Mol Sci 2021; 22:ijms222413400. [PMID: 34948198 PMCID: PMC8707487 DOI: 10.3390/ijms222413400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/06/2021] [Accepted: 12/10/2021] [Indexed: 01/13/2023] Open
Abstract
Green rods (GRs) represent a unique type of photoreceptor to be found in the retinas of anuran amphibians. These cells harbor a cone-specific blue-sensitive visual pigment but exhibit morphology of the outer segment typical for classic red rods (RRs), which makes them a perspective model object for studying cone–rod transmutation. In the present study, we performed detailed electrophysiological examination of the light sensitivity, response kinetics and parameters of discrete and continuous dark noise in GRs of the two anuran species: cane toad and marsh frog. Our results confirm that anuran GRs are highly specialized nocturnal vision receptors. Moreover, their rate of phototransduction quenching appeared to be about two-times slower than in RRs, which makes them even more efficient single photon detectors. The operating intensity ranges for two rod types widely overlap supposedly allowing amphibians to discriminate colors in the scotopic region. Unexpectedly for typical cone pigments but in line with some previous reports, the spontaneous isomerization rate of the GR visual pigment was found to be the same as for rhodopsin of RRs. Thus, our results expand the knowledge on anuran GRs and show that these are even more specialized single photon catchers than RRs, which allows us to assign them a status of “super-rods”.
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