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Shahu MK, Schuhmann F, Wong SY, Solov'yov IA, Koch KW. Allosteric Communication of the Dimerization and the Catalytic Domain in Photoreceptor Guanylate Cyclase. Biochemistry 2024; 63:2131-2140. [PMID: 39175413 PMCID: PMC11375764 DOI: 10.1021/acs.biochem.4c00170] [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: 08/24/2024]
Abstract
Phototransduction in vertebrate photoreceptor cells is controlled by Ca2+-dependent feedback loops involving the membrane-bound guanylate cyclase GC-E that synthesizes the second messenger guanosine-3',5'-cyclic monophosphate. Intracellular Ca2+-sensor proteins named guanylate cyclase-activating proteins (GCAPs) regulate the activity of GC-E by switching from a Ca2+-bound inhibiting state to a Ca2+-free/Mg2+-bound activating state. The gene GUCY2D encodes for human GC-E, and mutations in GUCY2D are often associated with an imbalance of Ca2+ and cGMP homeostasis causing retinal disorders. Here, we investigate the Ca2+-dependent inhibition of the constitutively active GC-E mutant V902L. The inhibition is not mediated by GCAP variants but by Ca2+ replacing Mg2+ in the catalytic center. Distant from the cyclase catalytic domain is an α-helical domain containing a highly conserved helix-turn-helix motif. Mutating the critical amino acid position 804 from leucine to proline left the principal activation mechanism intact but resulted in a lower level of catalytic efficiency. Our experimental analysis of amino acid positions in two distant GC-E domains implied an allosteric communication pathway connecting the α-helical and the cyclase catalytic domains. A computational connectivity analysis unveiled critical differences between wildtype GC-E and the mutant V902L in the allosteric network of critical amino acid positions.
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Affiliation(s)
- Manisha Kumari Shahu
- Department of Neuroscience, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg ,Germany
| | - Fabian Schuhmann
- Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Siu Ying Wong
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg ,Germany
- Center for Nanoscale Dynamics (CENAD), Institute of Physics, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
| | - Karl-Wilhelm Koch
- Department of Neuroscience, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg ,Germany
- Research Centre for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg ,Germany
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Biasi A, Marino V, Dal Cortivo G, Dell'Orco D. Supramolecular complexes of GCAP1: implications for inherited retinal dystrophies. Int J Biol Macromol 2024; 279:135068. [PMID: 39187109 DOI: 10.1016/j.ijbiomac.2024.135068] [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: 06/07/2024] [Revised: 08/16/2024] [Accepted: 08/23/2024] [Indexed: 08/28/2024]
Abstract
Guanylate Cyclase Activating Protein 1 (GCAP1) is a calcium sensor that regulates the enzymatic activity of retinal Guanylate Cyclase 1 (GC1) in photoreceptors in a Ca2+/Mg2+ dependent manner. While point mutations in GCAP1 have been associated with inherited retinal dystrophies (IRDs), their impact on protein dimerization or on the possible interaction with the potent GC1 inhibitor RD3 (retinal degeneration protein 3) has never been investigated. Here, we integrate exhaustive in silico investigations with biochemical assays to evaluate the effects of the p.(E111V) substitution, associated with a severe form of IRD, on GCAP1 homo- and hetero-dimerization, and demonstrate that wild type (WT) GCAP1 directly interacts with RD3. Although inducing constitutive activation in GC1, the E111V substitution only slightly affects the dimerization of GCAP1. Both WT- and E111V-GCAP1 are predominantly monomeric in the absence of the GC1 target, however E111V-GCAP1 shows a stronger tendency to be monomeric in the Ca2+-bound form, corresponding to GC1 inhibiting state. Reconstitution experiments performed in the co-presence of WT-GCAP1, E111V-GCAP1 and RD3 restored nearly physiological regulation of the GC1 enzymatic activity in terms of cGMP synthesis and Ca2+-sensitivity, suggesting new scenarios for biologics-mediated treatment of GCAP1-associated IRDs.
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Affiliation(s)
- Amedeo Biasi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy
| | - Valerio Marino
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy
| | - Giuditta Dal Cortivo
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy
| | - Daniele Dell'Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy.
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3
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Hill TJ, Sengupta P. Feedforward and feedback mechanisms cooperatively regulate rapid experience-dependent response adaptation in a single thermosensory neuron type. Proc Natl Acad Sci U S A 2024; 121:e2321430121. [PMID: 38530893 PMCID: PMC10998601 DOI: 10.1073/pnas.2321430121] [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: 12/05/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
Sensory adaptation allows neurons to adjust their sensitivity and responses based on recent experience. The mechanisms that mediate continuous adaptation to stimulus history over seconds- to hours-long timescales, and whether these mechanisms can operate within a single sensory neuron type, are unclear. The single pair of AFD thermosensory neurons in Caenorhabditis elegans exhibits experience-dependent plasticity in their temperature response thresholds on both minutes- and hours-long timescales upon a temperature upshift. While long-term response adaptation requires changes in gene expression in AFD, the mechanisms driving rapid response plasticity are unknown. Here, we show that rapid thermosensory response adaptation in AFD is mediated via cGMP and calcium-dependent feedforward and feedback mechanisms operating at the level of primary thermotransduction. We find that either of two thermosensor receptor guanylyl cyclases (rGCs) alone is sufficient to drive rapid adaptation, but that each rGC drives adaptation at different rates. rGC-driven adaptation is mediated in part via phosphorylation of their intracellular domains, and calcium-dependent feedback regulation of basal cGMP levels via a neuronal calcium sensor protein. In turn, cGMP levels feedforward via cGMP-dependent protein kinases to phosphorylate a specific subunit of the cGMP-gated thermotransduction channel to further regulate rapid adaptation. Our results identify multiple molecular pathways that act in AFD to ensure rapid adaptation to a temperature change and indicate that the deployment of both transcriptional and nontranscriptional mechanisms within a single sensory neuron type can contribute to continuous sensory adaptation.
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Affiliation(s)
- Tyler J. Hill
- Department of Biology, Brandeis University, Waltham, MA02454
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA02454
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4
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Li M, Dai Y, Hu S, Li Y, Lu D, Zheng R, Wang K. The association between preoperative blood calcium and postoperative blood loss in patients undergoing heart valve replacement surgery. Perfusion 2024; 39:310-316. [PMID: 36384323 DOI: 10.1177/02676591221140239] [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] [Indexed: 12/22/2023]
Abstract
INTRODUCTION Bleeding after heart valve surgery is a serious clinical challenge. Hypocalcemia has been associated with the extent of bleeding in patients with spontaneous intracerebral hemorrhage. However, the association between blood calcium levels and bleeding extent in heart valve replacement patients has not been clearly established. This study aimed at determining the association between blood calcium levels and perioperative hemorrhage after heart valve replacement therapy. METHODS Based on preoperative blood calcium levels, patients were grouped into the hypocalcemia group and normocalcemia group. Postoperative bleeding, blood product use, and complications were monitored during hospitalization. The association between blood calcium levels and major bleeding was determined by multivariable logistic regression models. RESULTS In the first 12 h after surgery, bleeding in hypocalcemia group was significantly larger than that of the normocalcemia group (338 ± 234 mL vs 232 ± 96 mL; p = .024). The outcome was the same when the overall chest tube output was considered (950 ± 447 mL vs 738 ± 220 mL; p = .038). The incidence of major bleeding was 65.91% in the hypocalcemia group and 18.97% in the normocalcemia group (p = .001). Postoperative complications in the two groups were similar. After adjusting for multiple covariates, the adjusted odds ratios (OR) for participants in hypocalcemia group was 10.01 (95% CI 3.35-34.82), compared with that in normocalcemia group (p < .001). CONCLUSION In patients undergoing heart valve surgery, preoperative blood concentrations of calcium are associated with postoperative blood loss. Hypocalcemia before operation may increase the risk of postoperative bleeding. When patients with valvular heart disease present with hypocalcemia before surgery, prompt intervention may lead to better control of postoperative bleeding.
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Affiliation(s)
- Mingke Li
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yawei Dai
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Shuai Hu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yansong Li
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Dasheng Lu
- Department of Cardiology, The Second Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Rui Zheng
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Kai Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Hill TJ, Sengupta P. Feedforward and feedback mechanisms cooperatively regulate rapid experience-dependent response adaptation in a single thermosensory neuron type. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570166. [PMID: 38168209 PMCID: PMC10760192 DOI: 10.1101/2023.12.05.570166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Sensory adaptation allows neurons to adjust their sensitivity and responses based on recent experience. The mechanisms that mediate continuous adaptation to stimulus history over seconds to hours long timescales, and whether these mechanisms can operate within a single sensory neuron type, are unclear. The single pair of AFD thermosensory neurons in C. elegans exhibits experience-dependent plasticity in their temperature response thresholds on both minutes- and hours-long timescales upon a temperature upshift. While long-term response adaptation requires changes in gene expression in AFD, the mechanisms driving rapid response plasticity are unknown. Here, we show that rapid thermosensory response adaptation in AFD is mediated via cGMP and calcium-dependent feedforward and feedback mechanisms operating at the level of primary thermotransduction. We find that either of two thermosensor receptor guanylyl cyclases (rGCs) alone is sufficient to drive rapid adaptation, but that each rGC drives adaptation at different rates. rGC-driven adaptation is mediated in part via phosphorylation of their intracellular domains, and calcium-dependent feedback regulation of basal cGMP levels via a neuronal calcium sensor protein. In turn, cGMP levels feedforward via cGMP-dependent protein kinases to phosphorylate a specific subunit of the cGMP-gated thermotransduction channel to further regulate rapid adaptation. Our results identify multiple molecular pathways that act in AFD to ensure rapid adaptation to a temperature change, and indicate that the deployment of both transcriptional and non-transcriptional mechanisms within a single sensory neuron type can contribute to continuous sensory adaptation.
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Affiliation(s)
- Tyler J. Hill
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454
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6
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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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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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8
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Koch KW. Molecular tuning of calcium dependent processes by neuronal calcium sensor proteins in the retina. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119491. [PMID: 37230154 DOI: 10.1016/j.bbamcr.2023.119491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 05/27/2023]
Abstract
Vertebrate photoreceptor cells are exquisite light detectors operating under very dim and bright illumination mediated by phototransduction, which is under control of the two secondary messengers cGMP and Ca2+. Feedback mechanisms enable photoreceptor cells to regain their responsiveness after light stimulation and involve neuronal Ca2+-sensor proteins, named GCAPs (guanylate cyclase-activating proteins) and recoverins. This review compares the diversity in Ca2+-related signaling mediated by GCAP and recoverin variants that exhibit differences in Ca2+-sensing, protein conformational changes, myristoyl switch mechanisms, diversity in divalent cation binding and dimer formation. In summary, both subclasses of neuronal Ca2+-sensor proteins contribute to a complex signaling network in rod and cone cells, which is perfectly suited to match the requirements for sensitive cell responses and maintaining this responsiveness in the presence of different background light intensities.
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Affiliation(s)
- Karl-Wilhelm Koch
- Department of Neuroscience, Division of Biochemistry, University of Oldenburg, 26111 Oldenburg, Germany.
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9
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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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10
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Yee C, Görtemaker K, Wellpott R, Koch KW. Kinetics of cone specific G-protein signaling in avian photoreceptor cells. Front Mol Neurosci 2023; 16:1107025. [PMID: 36733826 PMCID: PMC9887155 DOI: 10.3389/fnmol.2023.1107025] [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: 11/24/2022] [Accepted: 01/03/2023] [Indexed: 01/19/2023] Open
Abstract
Cone photoreceptor cells of night-migratory songbirds seem to process the primary steps of two different senses, vision and magnetoreception. The molecular basis of phototransduction is a prototypical G protein-coupled receptor pathway starting with the photoexcitation of rhodopsin or cone opsin thereby activating a heterotrimeric G protein named transducin. This interaction is well understood in vertebrate rod cells, but parameter describing protein-protein interactions of cone specific proteins are rare and not available for migratory birds. European robin is a model organism for studying the orientation of birds in the earth magnetic field. Recent findings showed a link between the putative magnetoreceptor cryptochrome 4a and the cone specific G-protein of European robin. In the present work, we investigated the interaction of European robin cone specific G protein and cytoplasmic regions of long wavelength opsin. We identified the second loop in opsin connecting transmembrane regions three and four as a critical binding interface. Surface plasmon resonance studies using a synthetic peptide representing the second cytoplasmic loop and purified G protein α-subunit showed a high affinity interaction with a K D value of 21 nM. Truncation of the G protein α-subunit at the C-terminus by six amino acids slightly decreased the affinity. Our results suggest that binding of the G protein to cryptochrome can compete with the interaction of G protein and non-photoexcited long wavelength opsin. Thus, the parallel presence of two different sensory pathways in bird cone photoreceptors is reasonable under dark-adapted conditions or during illumination with short wavelengths.
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Affiliation(s)
- Chad Yee
- Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Katharina Görtemaker
- Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Rieke Wellpott
- Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Karl-Wilhelm Koch
- Division of Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany,Research Center Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany,*Correspondence: Karl-Wilhelm Koch, ✉
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11
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Chen Y, Bräuer AU, Koch KW. Retinal degeneration protein 3 controls membrane guanylate cyclase activities in brain tissue. Front Mol Neurosci 2022; 15:1076430. [PMID: 36618828 PMCID: PMC9812585 DOI: 10.3389/fnmol.2022.1076430] [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: 10/21/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
The retinal degeneration protein RD3 is involved in regulatory processes of photoreceptor cells. Among its main functions is the inhibition of photoreceptor specific membrane guanylate cyclases during trafficking from the inner segment to their final destination in the outer segment. However, any physiological role of RD3 in non-retinal tissue is unsolved at present and specific protein targets outside of retinal tissue have not been identified so far. The family of membrane bound guanylate cyclases share a high homology of their amino acid sequences in their cytoplasmic domains. Therefore, we reasoned that membrane guanylate cyclases that are activated by natriuretic peptides are also regulated by RD3. We analyzed transcript levels of the rd3 gene and natriuretic peptide receptor genes Npr1 and Npr2 in the mouse retina, cerebellum, hippocampus, neocortex, and the olfactory bulb during development from the embryonic to the postnatal stage at P60. The rd3 gene showed a lower expression level than Npr1 and Npr2 (encoding for GC-A and GC-B, respectively) in all tested brain tissues, but was at least one order of magnitude higher in the retina. RD3 and natriuretic peptide receptor GCs co-express in the retina and brain tissue leading to functional tests. We expressed GC-A and GC-B in HEK293T cells and measured the inhibition of GCs by RD3 after activation by natriuretic peptides yielding inhibitory constants around 25 nM. Furthermore, endogenous GCs in astrocytes were inhibited by RD3 to a similar extent. We here show for the first time that RD3 can inhibit two hormone-stimulated GCs, namely GC-A and GC-B indicating a new regulatory feature of these hormone receptors.
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Affiliation(s)
- Yaoyu Chen
- Division of Biochemistry, Department of Neuroscience, Carl von Ossietzky University, Oldenburg, Germany,Division of Anatomy, Department of Human Medicine, Carl von Ossietzky University, Oldenburg, Germany
| | - Anja U. Bräuer
- Division of Anatomy, Department of Human Medicine, Carl von Ossietzky University, Oldenburg, Germany,Research Center Neurosensory Science, Carl von Ossietzky University, Oldenburg, Germany
| | - Karl-Wilhelm Koch
- Division of Biochemistry, Department of Neuroscience, Carl von Ossietzky University, Oldenburg, Germany,Research Center Neurosensory Science, Carl von Ossietzky University, Oldenburg, Germany,*Correspondence: Karl-Wilhelm Koch,
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12
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Jacobson SG, Cideciyan AV, Ho AC, Roman AJ, Wu V, Garafalo AV, Sumaroka A, Krishnan AK, Swider M, Mascio AA, Kay CN, Yoon D, Fujita KP, Boye SL, Peshenko IV, Dizhoor AM, Boye SE. Night vision restored in days after decades of congenital blindness. iScience 2022; 25:105274. [PMID: 36274938 PMCID: PMC9579015 DOI: 10.1016/j.isci.2022.105274] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/29/2022] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
Signaling of vision to the brain starts with the retinal phototransduction cascade which converts visible light from the environment into chemical changes. Vision impairment results when mutations inactivate proteins of the phototransduction cascade. A severe monogenically inherited blindness, Leber congenital amaurosis (LCA), is caused by mutations in the GUCY2D gene, leading to a molecular defect in the production of cyclic GMP, the second messenger of phototransduction. We studied two patients with GUCY2D-LCA who were undergoing gene augmentation therapy. Both patients had large deficits in rod photoreceptor-based night vision before intervention. Within days of therapy, rod vision in both patients changed dramatically; improvements in visual function and functional vision in these hyper-responding patients reached more than 3 log10 units (1000-fold), nearing healthy rod vision. Quick activation of the complex molecular pathways from retinal photoreceptor to visual cortex and behavior is thus possible in patients even after being disabled and dormant for decades.
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Affiliation(s)
- Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Allen C. Ho
- Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexandra V. Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arun K. Krishnan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Abraham A. Mascio
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Dan Yoon
- Atsena Therapeutics, Inc., Durham, NC 27709, USA
| | | | - Sanford L. Boye
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL 32601, USA
| | - Igor V. Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027, USA
| | | | - Shannon E. Boye
- Department of Pediatrics, Division of Cellular and Molecular Therapy, University of Florida College of Medicine, Gainesville, FL 32611, USA
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Retinal degeneration-3 protein attenuates photoreceptor degeneration in transgenic mice expressing dominant mutation of human retinal guanylyl cyclase. J Biol Chem 2021; 297:101201. [PMID: 34537244 PMCID: PMC8517212 DOI: 10.1016/j.jbc.2021.101201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 11/22/2022] Open
Abstract
Different forms of photoreceptor degeneration cause blindness. Retinal degeneration-3 protein (RD3) deficiency in photoreceptors leads to recessive congenital blindness. We proposed that aberrant activation of the retinal membrane guanylyl cyclase (RetGC) by its calcium-sensor proteins (guanylyl cyclase-activating protein [GCAP]) causes this retinal degeneration and that RD3 protects photoreceptors by preventing such activation. We here present in vivo evidence that RD3 protects photoreceptors by suppressing activation of both RetGC1 and RetGC2 isozymes. We further suggested that insufficient inhibition of RetGC by RD3 could contribute to some dominant forms of retinal degeneration. The R838S substitution in RetGC1 that causes autosomal-dominant cone-rod dystrophy 6, not only impedes deceleration of RetGC1 activity by Ca2+GCAPs but also elevates this isozyme's resistance to inhibition by RD3. We found that RD3 prolongs the survival of photoreceptors in transgenic mice harboring human R838S RetGC1 (R838S+). Overexpression of GFP-tagged human RD3 did not improve the calcium sensitivity of cGMP production in R838S+ retinas but slowed the progression of retinal blindness and photoreceptor degeneration. Fluorescence of the GFP-tagged RD3 in the retina only partially overlapped with immunofluorescence of RetGC1 or GCAP1, indicating that RD3 separates from the enzyme before the RetGC1:GCAP1 complex is formed in the photoreceptor outer segment. Most importantly, our in vivo results indicate that, in addition to the abnormal Ca2+ sensitivity of R838S RetGC1 in the outer segment, the mutated RetGC1 becomes resistant to inhibition by RD3 in a different cellular compartment(s) and suggest that RD3 overexpression could be utilized to reduce the severity of cone-rod dystrophy 6 pathology.
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Affiliation(s)
- Daniele Dell'Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada le Grazie 8, I-37124, Verona, Italy
| | - Karl-Wilhelm Koch
- Department of Neuroscience, Division of Biochemistry, University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, D-26111, Oldenburg, Germany
| | - Giorgio Rispoli
- Department of Neuroscience and Rehabilitation, Section of Physiology, Via Borsari 46, I-44121, Ferrara, Italy.
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