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Yang F, Zhang H, Yu X, Tao Q, Zhao C, An J, Zhang X, Li X. TNFAIP8 overexpression aggravates retinal pathophysiological features of diabetic retinopathy. Exp Eye Res 2023; 234:109572. [PMID: 37451566 DOI: 10.1016/j.exer.2023.109572] [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: 02/28/2023] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Our previous research shown that tumor necrosis factor-alpha-induced protein 8 (TNFAIP8) is elevated in the plasma extracellular vesicles and vitreous humor in diabetic retinopathy (DR). TNFAIP8 also significantly increases the viability of human retinal microvascular endothelial cells (HRMECs) and promotes cell migration and tube formation in vitro. To comprehensively explore its role in DR, we investigated the effect of TNFAIP8 on DR development using an animal model in this study. A TNFAIP8-overexpressing adeno-associated virus (AAV) vector and streptozotocin-induced mouse model was used. The AAV-TNFAIP8 vector was injected into the mice intravitreally, and the effect was evaluated. The evaluation included analysis of retinal structure and function using electroretinography, optical coherence tomography, and histological assessment. The influence of TNFAIP8 on the avascular area, retinal leukostasis, and the expression levels of inflammatory factors was also determined. TNFAIP8 significantly decreased a/b-wave amplitude and retinal thickness in diabetic mice. Histological assessment showed that TNFAIP8 aggravated pathological abnormalities with distorted organization of the retina. TNFAIP8 also significantly increased the avascular area, leukostasis, and the expression of inflammatory factors, such as TNFα, IL1β, ICAM1, and GFAP, in the retina. The results of this study support the role of TNFAIP8 in DR pathogenesis. A mechanistic understanding of TNFAIP8 may offer novel therapeutic strategies.
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Affiliation(s)
- Fuhua Yang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Hui Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Xinyue Yu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Qingqin Tao
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Chuan Zhao
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Jinying An
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Xiaomin Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China.
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China.
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Strickland R, Landis EG, Pardue MT. Short-Wavelength (Violet) Light Protects Mice From Myopia Through Cone Signaling. Invest Ophthalmol Vis Sci 2020; 61:13. [PMID: 32049342 PMCID: PMC7326482 DOI: 10.1167/iovs.61.2.13] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose Exposure to short-wavelength light influences refractive development and inhibits myopic development in many animal models. Retinal mechanisms underlying this response remain unknown. This study used a mouse model of lens-induced myopia to evaluate the effect of different wavelength light on refractive development and dopamine levels in the retina. A possible retinal pathway is tested using a mutant mouse with dysfunctional cones. Methods Wild-type C57BL/6J (WT) and ALS/LtJ/Gnat2cpfl3 (Gnat2−/−) mice were exposed to one of three different light conditions beginning at postnatal day 28: broad-spectrum “white” (420-680 nm), medium wavelength “green” (525 ± 40 nm), and short wavelength “violet” (400 ± 20 nm). One-half of the mice received hyperopic lens defocus. All mice were exposed to the light for 4 weeks; animals were measured weekly for refractive error and axial parameters. Retinal dopamine and the dopamine metabolite 3,4-dihydroxyphenylacetic acid were measured by HPLC. Results In WT mice, short-wavelength violet light induced hyperopia and violet light inhibited lens-induced myopia when compared with mice exposed to white light. Hyperopia could be attributed to shallower vitreous chambers in WT animals. There were no changes in the levels of dopamine or its metabolite. In Gnat2−/− mice, violet light did not induce hyperopia or inhibit lens-induced myopia. Conclusions These findings show that short-wavelength light slows refractive eye growth, producing hyperopic responses in mice and inhibiting lens-induced myopia. The lack of inhibition in mice with dysfunctional cones suggests that cone signaling plays a role in the hyperopic response to short-wavelength (violet) light.
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Han JYS, Kinoshita J, Bisetto S, Bell BA, Nowak RA, Peachey NS, Philp NJ. Role of monocarboxylate transporters in regulating metabolic homeostasis in the outer retina: Insight gained from cell-specific Bsg deletion. FASEB J 2020; 34:5401-5419. [PMID: 32112484 DOI: 10.1096/fj.201902961r] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/29/2020] [Accepted: 02/07/2020] [Indexed: 02/06/2023]
Abstract
The neural retina metabolizes glucose through aerobic glycolysis generating large amounts of lactate. Lactate flux into and out of cells is regulated by proton-coupled monocarboxylate transporters (MCTs), which are encoded by members of the Slc16a family. MCT1, MCT3, and MCT4 are expressed in the retina and require association with the accessory protein basigin, encoded by Bsg, for maturation and trafficking to the plasma membrane. Bsg-/- mice have severely reduced electroretinograms (ERGs) and progressive photoreceptor degeneration, which is presumed to be driven by metabolic dysfunction resulting from loss of MCTs. To understand the basis of the Bsg-/- phenotype, we generated mice with conditional deletion of Bsg in rods (RodΔBsg), cones (Cone∆Bsg), or retinal pigment epithelial cells (RPEΔBsg). RodΔBsg mice showed a progressive loss of photoreceptors, while ConeΔBsg mice did not display a degenerative phenotype. The RPEΔBsg mice developed a distinct phenotype characterized by severely reduced ERG responses as early as 4 weeks of age. The loss of lactate transporters from the RPE most closely resembled the phenotype of the Bsg-/- mouse, suggesting that the regulation of lactate levels in the RPE and the subretinal space is essential for the viability and function of photoreceptors.
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Affiliation(s)
- John Y S Han
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Sara Bisetto
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Brent A Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Romana A Nowak
- Animal Sciences, University of Illinois at Urbana-Champaign, Urbana-Champaign, IL, USA
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
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Santos RAS. Genetic Models. ANGIOTENSIN-(1-7) 2019. [PMCID: PMC7120897 DOI: 10.1007/978-3-030-22696-1_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genetically altered rat and mouse models have been instrumental in the functional analysis of genes in a physiological context. In particular, studies on the renin-angiotensin system (RAS) have profited from this technology in the past. In this review, we summarize the existing animal models for the protective axis of the RAS consisting of angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7)(Ang-(1-7), and its receptor Mas. With the help of models with altered expression of the components of this axis in the brain and cardiovascular organs, its physiological and pathophysiological functions have been elucidated. Thus, novel opportunities for therapeutic interventions in cardiovascular diseases were revealed targeting ACE2 or Mas.
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Santos RAS, Sampaio WO, Alzamora AC, Motta-Santos D, Alenina N, Bader M, Campagnole-Santos MJ. The ACE2/Angiotensin-(1-7)/MAS Axis of the Renin-Angiotensin System: Focus on Angiotensin-(1-7). Physiol Rev 2018; 98:505-553. [PMID: 29351514 PMCID: PMC7203574 DOI: 10.1152/physrev.00023.2016] [Citation(s) in RCA: 681] [Impact Index Per Article: 113.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The renin-angiotensin system (RAS) is a key player in the control of the cardiovascular system and hydroelectrolyte balance, with an influence on organs and functions throughout the body. The classical view of this system saw it as a sequence of many enzymatic steps that culminate in the production of a single biologically active metabolite, the octapeptide angiotensin (ANG) II, by the angiotensin converting enzyme (ACE). The past two decades have revealed new functions for some of the intermediate products, beyond their roles as substrates along the classical route. They may be processed in alternative ways by enzymes such as the ACE homolog ACE2. One effect is to establish a second axis through ACE2/ANG-(1-7)/MAS, whose end point is the metabolite ANG-(1-7). ACE2 and other enzymes can form ANG-(1-7) directly or indirectly from either the decapeptide ANG I or from ANG II. In many cases, this second axis appears to counteract or modulate the effects of the classical axis. ANG-(1-7) itself acts on the receptor MAS to influence a range of mechanisms in the heart, kidney, brain, and other tissues. This review highlights the current knowledge about the roles of ANG-(1-7) in physiology and disease, with particular emphasis on the brain.
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Affiliation(s)
- Robson Augusto Souza Santos
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Walkyria Oliveira Sampaio
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Andreia C Alzamora
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Daisy Motta-Santos
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Natalia Alenina
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Michael Bader
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Maria Jose Campagnole-Santos
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
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Bader M, Alenina N, Andrade-Navarro MA, Santos RA. MAS and its related G protein-coupled receptors, Mrgprs. Pharmacol Rev 2015; 66:1080-105. [PMID: 25244929 DOI: 10.1124/pr.113.008136] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Mas-related G protein-coupled receptors (Mrgprs or Mas-related genes) comprise a subfamily of receptors named after the first discovered member, Mas. For most Mrgprs, pruriception seems to be the major function based on the following observations: 1) they are relatively promiscuous in their ligand specificity with best affinities for itch-inducing substances; 2) they are expressed in sensory neurons and mast cells in the skin, the main cellular components of pruriception; and 3) they appear in evolution first in tetrapods, which have arms and legs necessary for scratching to remove parasites or other noxious substances from the skin before they create harm. Because parasites coevolved with hosts, each species faced different parasitic challenges, which may explain another striking observation, the multiple independent duplication and expansion events of Mrgpr genes in different species as a consequence of parallel adaptive evolution. Their predominant expression in dorsal root ganglia anticipates additional functions of Mrgprs in nociception. Some Mrgprs have endogenous ligands, such as β-alanine, alamandine, adenine, RF-amide peptides, or salusin-β. However, because the functions of these agonists are still elusive, the physiologic role of the respective Mrgprs needs to be clarified. The best studied Mrgpr is Mas itself. It was shown to be a receptor for angiotensin-1-7 and to exert mainly protective actions in cardiovascular and metabolic diseases. This review summarizes the current knowledge about Mrgprs, their evolution, their ligands, their possible physiologic functions, and their therapeutic potential.
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Affiliation(s)
- Michael Bader
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Miguel A Andrade-Navarro
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Robson A Santos
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
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Animal Models with a Genetic Alteration of the ACE2/Ang-(1-7)/Mas Axis. THE PROTECTIVE ARM OF THE RENIN ANGIOTENSIN SYSTEM (RAS) 2015. [PMCID: PMC7150279 DOI: 10.1016/b978-0-12-801364-9.00022-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aim of this chapter is to describe the animal models generated by transgenic technology for the functional analysis of the protective axis of the renin–angiotensin system, consisting of angiotensin-converting enzyme 2 (ACE2), angiotensin (Ang)-(1-7), and Mas. Transgenic overexpression of the components of this axis in general led to an ameliorated cardiac and vascular damage in disease states and to an improved metabolic profile. Knockout models for ACE2 and Mas, however, show aggravated cardiovascular pathologies and a metabolic syndrome-like state. In particular, the local production of Ang-(1-7) in the vascular wall, in the heart, and in the brain was found to be of high physiological relevance by the use of transgenic animals overexpressing ACE2 or Ang-(1-7) in these tissues.
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Abstract
The b-wave is a major component of the electroretinogram that reflects the activity of depolarizing bipolar cells (DBCs). The b-wave is used diagnostically to identify patients with defects in DBC signaling or in transmission from photoreceptors to DBCs. In mouse models, an abnormal b-wave has been used to demonstrate a critical role of a particular protein in the release of glutamate from photoreceptor terminals, in establishing the structure of the photoreceptor-to-DBC synapse, in DBC signal transduction, and also in DBC development, survival, or metabolic support. The purpose of this review is to summarize these models and how they have advanced our understanding of outer retinal function.
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Cho KI, Haque M, Wang J, Yu M, Hao Y, Qiu S, Pillai ICL, Peachey NS, Ferreira PA. Distinct and atypical intrinsic and extrinsic cell death pathways between photoreceptor cell types upon specific ablation of Ranbp2 in cone photoreceptors. PLoS Genet 2013; 9:e1003555. [PMID: 23818861 PMCID: PMC3688534 DOI: 10.1371/journal.pgen.1003555] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 04/23/2013] [Indexed: 12/26/2022] Open
Abstract
Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2), a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+-apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct retinal spatial signatures as well as with other etiologically distinct neurodegenerative disorders. The secondary demise of healthy neurons upon the degeneration of neurons harboring primary genetic defect(s) is hallmark to neurodegenerative diseases. However, the factors and mechanisms driving these cell-death processes are not understood, a severe limitation which has hampered the therapeutic development of neuroprotective approaches. The neuroretina is comprised of two main types of photoreceptor neurons, rods and cones. These undergo degeneration upon heterogeneous mutations or environmental stressors and the underlying diseases present conspicuous spatiotemporal pathological signatures whose molecular bases are not understood. We employed the multifunctional protein, Ran-binding protein-2 (Ranbp2), which is implicated in cell-type and stress-dependent clinical manifestations, to examine its role(s) in primary and secondary photoreceptor death mechanisms upon its specific loss in cones. Contrary to prior findings, we found that dying cones can trigger the loss of healthy rods. This process arises by the immediate activation of novel Ranbp2-responsive factors and downstream cascade events in cones that promote extrinsically the demise of rods. The mechanisms of rod and cone demise are molecularly distinct. Collectively, the data uncover distinct Ranbp2 roles in intrinsic and extrinsic cell-death and will likely contribute to our understanding of the spatiotemporal onset and progression of diseases affecting photoreceptor mosaics and other neural networks.
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Affiliation(s)
- Kyoung-in Cho
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - MdEmdadul Haque
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jessica Wang
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sunny Qiu
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Indulekha C. L. Pillai
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
- Research Service, Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Paulo A. Ferreira
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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Vuong L, Brobst DE, Ivanovic I, Sherry DM, Al-Ubaidi MR. p53 selectively regulates developmental apoptosis of rod photoreceptors. PLoS One 2013; 8:e67381. [PMID: 23840687 PMCID: PMC3688626 DOI: 10.1371/journal.pone.0067381] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 05/17/2013] [Indexed: 12/14/2022] Open
Abstract
Retinal cells become post-mitotic early during post-natal development. It is likely that p53, a well-known cell cycle regulator, is involved in regulating the genesis, differentiation and death of retinal cells. Furthermore, retinal cells are under constant oxidative stress that can result in DNA damage, due to the extremely high level of metabolic activity associated with phototransduction. If not repaired, this damage may result in p53-dependent cell death and ensuing vision loss. In this study, the role of p53 during retinal development and in the post-mitotic retina is investigated. A previously described super p53 transgenic mouse that expresses an extra copy of the mouse p53 gene driven by its endogenous promoter is utilized. Another transgenic mouse (HIP) that expresses the p53 gene in rod and cone photoreceptors driven by the human interphotoreceptor retinoid binding protein promoter was generated. The electroretinogram (ERG) of the super p53 mouse exhibited reduced rod-driven scotopic a and b wave and cone-driven photopic b wave responses. This deficit resulted from a reduced number of rod photoreceptors and inner nuclear layer cells. However, the reduced photopic signal arose only from lost inner retinal neurons, as cone numbers did not change. Furthermore, cell loss was non-progressive and resulted from increased apoptosis during retinal developmental as determined by TUNEL staining. In contrast, the continuous and specific expression of p53 in rod and cone photoreceptors in the mature retinas of HIP mice led to the selective loss of both rods and cones. These findings strongly support a role for p53 in regulating developmental apoptosis in the retina and suggest a potential role, either direct or indirect, for p53 in the degenerative photoreceptor loss associated with human blinding disorders.
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Affiliation(s)
- Linda Vuong
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Daniel E. Brobst
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Ivana Ivanovic
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - David M. Sherry
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Muayyad R. Al-Ubaidi
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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Focus on Brain Angiotensin III and Aminopeptidase A in the Control of Hypertension. Int J Hypertens 2012; 2012:124758. [PMID: 22792446 PMCID: PMC3389720 DOI: 10.1155/2012/124758] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/26/2012] [Indexed: 01/30/2023] Open
Abstract
The classic renin-angiotensin system (RAS) was initially described as a hormone system designed to mediate cardiovascular and body water regulation. The discovery of a brain RAS composed of the necessary functional components (angiotensinogen, peptidases, angiotensins, and specific receptor proteins) independent of the peripheral system significantly expanded the possible physiological and pharmacological functions of this system. This paper first describes the enzymatic pathways resulting in active angiotensin ligands and their interaction with AT1, AT2, and mas receptor subtypes. Recent evidence points to important contributions by brain angiotensin III (AngIII) and aminopeptidases A (APA) and N (APN) in sustaining hypertension. Next, we discuss current approaches to the treatment of hypertension followed by novel strategies that focus on limiting the binding of AngII and AngIII to the AT1 receptor subtype by influencing the activity of APA and APN. We conclude with thoughts concerning future treatment approaches to controlling hypertension and hypotension.
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Audo I, Bujakowska KM, Léveillard T, Mohand-Saïd S, Lancelot ME, Germain A, Antonio A, Michiels C, Saraiva JP, Letexier M, Sahel JA, Bhattacharya SS, Zeitz C. Development and application of a next-generation-sequencing (NGS) approach to detect known and novel gene defects underlying retinal diseases. Orphanet J Rare Dis 2012; 7:8. [PMID: 22277662 PMCID: PMC3352121 DOI: 10.1186/1750-1172-7-8] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 01/25/2012] [Indexed: 12/25/2022] Open
Abstract
Background Inherited retinal disorders are clinically and genetically heterogeneous with more than 150 gene defects accounting for the diversity of disease phenotypes. So far, mutation detection was mainly performed by APEX technology and direct Sanger sequencing of known genes. However, these methods are time consuming, expensive and unable to provide a result if the patient carries a new gene mutation. In addition, multiplicity of phenotypes associated with the same gene defect may be overlooked. Methods To overcome these challenges, we designed an exon sequencing array to target 254 known and candidate genes using Agilent capture. Subsequently, 20 DNA samples from 17 different families, including four patients with known mutations were sequenced using Illumina Genome Analyzer IIx next-generation-sequencing (NGS) platform. Different filtering approaches were applied to identify the genetic defect. The most likely disease causing variants were analyzed by Sanger sequencing. Co-segregation and sequencing analysis of control samples validated the pathogenicity of the observed variants. Results The phenotype of the patients included retinitis pigmentosa, congenital stationary night blindness, Best disease, early-onset cone dystrophy and Stargardt disease. In three of four control samples with known genotypes NGS detected the expected mutations. Three known and five novel mutations were identified in NR2E3, PRPF3, EYS, PRPF8, CRB1, TRPM1 and CACNA1F. One of the control samples with a known genotype belongs to a family with two clinical phenotypes (Best and CSNB), where a novel mutation was identified for CSNB. In six families the disease associated mutations were not found, indicating that novel gene defects remain to be identified. Conclusions In summary, this unbiased and time-efficient NGS approach allowed mutation detection in 75% of control cases and in 57% of test cases. Furthermore, it has the possibility of associating known gene defects with novel phenotypes and mode of inheritance.
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Sherry DM, Murray AR, Kanan Y, Arbogast KL, Hamilton RA, Fliesler SJ, Burns ME, Moore KL, Al-Ubaidi MR. Lack of protein-tyrosine sulfation disrupts photoreceptor outer segment morphogenesis, retinal function and retinal anatomy. Eur J Neurosci 2010; 32:1461-72. [PMID: 21039965 DOI: 10.1111/j.1460-9568.2010.07431.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
To investigate the role(s) of protein-tyrosine sulfation in the retina, we examined retinal function and structure in mice lacking tyrosylprotein sulfotransferases (TPST) 1 and 2. Tpst double knockout (DKO; Tpst1(-/-) /Tpst2 (-/-) ) retinas had drastically reduced electroretinographic responses, although their photoreceptors exhibited normal responses in single cell recordings. These retinas appeared normal histologically; however, the rod photoreceptors had ultrastructurally abnormal outer segments, with membrane evulsions into the extracellular space, irregular disc membrane spacing and expanded intradiscal space. Photoreceptor synaptic terminals were disorganized in Tpst DKO retinas, but established ultrastructurally normal synapses, as did bipolar and amacrine cells; however, the morphology and organization of neuronal processes in the inner retina were abnormal. These results indicate that protein-tyrosine sulfation is essential for proper outer segment morphogenesis and synaptic function, but is not critical for overall retinal structure or synapse formation, and may serve broader functions in neuronal development and maintenance.
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Affiliation(s)
- David M Sherry
- Department of Cell Biology, University of Oklahoma Health Sciences Center, BMSB 781, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
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14
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Bai Y, Ma JX, Guo J, Wang J, Zhu M, Chen Y, Le YZ. Müller cell-derived VEGF is a significant contributor to retinal neovascularization. J Pathol 2010; 219:446-54. [PMID: 19768732 DOI: 10.1002/path.2611] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vascular endothelial growth factor (VEGF-A) is a major pathogenic factor and a therapeutic target for age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity. Despite intensive effort in the field, the cellular mechanisms of VEGF action remain virtually uninvestigated. This situation makes it difficult to design cellular target-based therapeutics for these diseases. In light of the recent finding that VEGF is a potential neurotrophic factor, revealing the cellular mechanisms of VEGF action becomes necessary to preserve its beneficial effect and inhibit its pathological function in long-term anti-VEGF therapeutics for ocular vascular diseases. We therefore generated conditional VEGF knockout mice with an inducible Cre/lox system and determined the significance of Müller cell-derived VEGF in retinal development and maintenance and ischaemia-induced neovascularizartion and vascular leakage. Retinal development in the conditional VEGF knockout mice was analysed by examining retinal and choroidal vasculatures and retinal morphology and function. Ischaemia-induced retinal neovascularization and vascular leakage in the conditional VEGF knockout mice were analysed with fluorescein angiography, quantification of proliferative neovascular cells, immunohistochemistry, and immunoblotting using an oxygen-induced retinopathy model. Our results demonstrated that disruption of Müller cell-derived VEGF resulted in no apparent defects in retinal and choroidal vasculatures and retinal morphology and function, significant inhibition of the ischaemia-induced retinal neovascularization and vascular leakage, and attenuation of the ischaemia-induced breakdown of the blood-retina barrier. These results suggest that the retinal Müller cell-derived VEGF is a major contributor to ischaemia-induced retinal vascular leakage and pre-retinal and intra-retinal neovascularization. The observation that a significant, but not complete, reduction of VEGF in the retina does not cause detectable retinal degeneration suggests that appropriate doses of anti-VEGF agents may be important to the safe treatment of retinal vascular diseases.
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Affiliation(s)
- Yanyan Bai
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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15
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Kanan Y, Hoffhines A, Rauhauser A, Murray A, Al-Ubaidi MR. Protein tyrosine-O-sulfation in the retina. Exp Eye Res 2009; 89:559-67. [PMID: 19523945 PMCID: PMC2940935 DOI: 10.1016/j.exer.2009.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 05/18/2009] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
Abstract
Tyrosine-O-sulfation, a post-translational modification, is catalyzed by two independent tyrosylprotein sulfotransferases (TPSTs). As an initial step towards understanding the role of TPSTs in retinal function, this study was undertaken to determine the extent to which tyrosine-O-sulfation of proteins is utilized in the retina. A previously characterized anti-sulfotyrosine antibody was used to determine the presence and localization of tyrosine-O-sulfated proteins (TOSPs) in the retina. Using Western blot, RT-PCR and immunohistochemical analyses, we detected TOSPs in the retinas from diverse species, including frog, fish, mouse and human. Some of the variability in the observed sizes of retinal TOSPs in the mouse, at least, may result from differential patterns of glycosylation; however, there seem to be species-specific sulfated retinal proteins as well. TOSPs were detected in most of the retinal layers as well as in the retinal pigment epithelium from human and mouse. Several retinal TOSPs were detected in the inter-photoreceptor matrix, which is consistent with the secreted nature of some sulfated proteins. Transcripts for both TPST-1 and TPST-2 were expressed in both the human and mouse retinas. These data show that retinal protein tyrosine-O-sulfation is highly conserved which suggest a functional significance of these proteins to retinal function and structure.
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Affiliation(s)
| | | | | | | | - Muayyad R. Al-Ubaidi
- Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
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16
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Ueki Y, Ash JD, Zhu M, Zheng L, Le YZ. Expression of Cre recombinase in retinal Müller cells. Vision Res 2009; 49:615-21. [PMID: 19948109 DOI: 10.1016/j.visres.2009.01.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 01/21/2009] [Accepted: 01/25/2009] [Indexed: 10/21/2022]
Abstract
PURPOSE In an effort to generate inducible RPE-specific Cre mice using a 3.0-kb human vitelliform macular dystrophy-2 (VMD2) promoter, we identified a mouse line with unanticipated Cre activity in the neural retina, including Müller glial cells. Müller cells play important roles in the function and maintenance of the retina, and this mouse line would be potentially useful for conditional gene targeting in Müller glia. We therefore characterized the timing, inducibility, and cell specificity of Cre expression, as well as Müller cell-specific efficiency of Cre-mediated recombination in this mouse line. METHODS Transgenic mice carrying cassettes of human P(VMD2)-rtTA and TRE-cre were generated. Cre expression was characterized using a Cre-activatable lacZ reporter mouse line (R26R) and a floxed interleukin six signal transducing receptor (gp130) mouse line. RESULTS beta-Galactosidase (beta-gal) assay and immunohistochemical analysis of VMD2-cre/R26R double transgenic mice indicated that Cre activity was detected in cells located in the inner nuclear layer, with prominent expression of beta-gal in Müller cells. Cre activity was also detected in photoreceptors in the outer nuclear layer. PCR analysis demonstrated that Cre-mediated recombination initiated by embryonic day 15. Immunohistochemical analysis indicated that Cre-mediated deletion of floxed gp130 gene occurred in 52% of the retinal Müller cells. Retinal function and morphology were normal in 10-month-old VMD2-cre mice. CONCLUSION We generated a transgenic cre mouse that is useful to study gene activation and inactivation in retinal Müller cells.
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Affiliation(s)
- Yumi Ueki
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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17
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Le YZ, Zheng W, Rao PC, Zheng L, Anderson RE, Esumi N, Zack DJ, Zhu M. Inducible expression of cre recombinase in the retinal pigmented epithelium. Invest Ophthalmol Vis Sci 2008; 49:1248-53. [PMID: 18326755 DOI: 10.1167/iovs.07-1105] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The retinal pigmented epithelium (RPE) expresses many genes that play important roles in the support and maintenance of photoreceptors. The present study was conducted to develop a system amenable to the dissection of the temporal function of these genes, specifically within RPE cells. Transgenic mice were generated and characterized in which the expression of Cre recombinase could be specifically induced within the RPE. METHODS Transgenic mice carrying the human vitelliform macular dystrophy-2 (VMD2) promoter (P(VMD2))-directed reverse tetracycline-dependent transactivator (rtTA) and the tetracycline-responsive element (TRE)-directed cre were generated. Inducible Cre expression was achieved by feeding doxycycline to these mice and was characterized by using a Cre-activatable lacZ reporter mouse strain (R26R). RESULTS A beta-galactosidase assay of rtTA/Cre-R26R mice demonstrated that the basal level of Cre expression without doxycycline induction was negligible. Addition of doxycycline led to induction of RPE-specific Cre expression/function at least from embryonic day 9 to postnatal day 60. The highest induction occurred at approximately postnatal day 4. As measured by ERG and histology, retinal function and morphology were normal in 10-month-old rtTA/Cre mice that were treated with doxycycline at weaning age. CONCLUSIONS Transgenic mice were generated that express Cre recombinase in the RPE in an inducible fashion. These mice will be useful for studies of the RPE-specific role of genes that are expressed in the RPE as well as other cells, particularly for avoiding embryonic lethality and dissecting the function of genes that play dual roles in development and adulthood.
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Affiliation(s)
- Yun-Zheng Le
- Department of Medicine and Harold Hamm Oklahoma Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Alenina N, Xu P, Rentzsch B, Patkin EL, Bader M. Genetically altered animal models for Mas and angiotensin-(1-7). Exp Physiol 2007; 93:528-37. [PMID: 18156169 DOI: 10.1113/expphysiol.2007.040345] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mas is the receptor for angiotensin-(1-7) and is involved in cardiovascular and neuronal regulation, in which the heptapeptide also plays a major role. Mas-deficient mice have been generated by us, and their characterization has shown that Mas has important functions in behaviour and cardiovascular regulation. These mice exhibit increased anxiety but, despite an enhanced long-term potentiation in the hippocampus, do not perform better in learning experiments. When Mas-deficient mice are backcrossed to the FVB/N genetic background, a cardiovascular phenotype is uncovered, in that the backcrossed animals become hypertensive. Concordant with our detection by fluorescent in situ hybridization of Mas mRNA in mouse endothelium, this phenotype is caused by endothelial dysfunction based on a dysbalance between nitric oxide and reactive oxygen species in the vessel wall. In agreement with these data, transgenic spontaneously hypertensive stroke-prone rats overexpressing ACE2 in the vessel wall exhibit reduced blood pressure as a result of improved endothelial function. Moreover, angiotensin-(1-7) overexpression in transgenic rats has cardioprotective and haemodynamic effects. In conclusion, the angiotensin-(1-7)-Mas axis has important functional implications for vascular regulation and blood pressure control, particularly in pathophysiological situations.
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Affiliation(s)
- Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine (MDC), Robert-Rössle-Strasse 10, D-13092 Berlin-Buch, Germany
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19
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Le YZ, Ash JD, Al-Ubaidi MR, Chen Y, Ma JX, Anderson RE. Conditional gene knockout system in cone photoreceptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 572:173-8. [PMID: 17249572 DOI: 10.1007/0-387-32442-9_26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
To study function of widely expressed essential genes, we established a conditional knockout system for cone photoreceptor cells. Our goal is to generate a useful genetic system that can be utilized to disrupt gene function efficiently in cone photoreceptor cells. Functional assay using a Cre-activatable lacZ reporter gene suggested that HRGP-cre mice had widely expressed functional Cre in cone photoreceptors. Since nearly all cone photoreceptor cells express Cre in our transgenic mice, they will be efficient in carrying out Cre-mediated gene activation and inactivation in both M- and S-cone photoreceptors. In addition, we have not observed any apparent ectopic expression in HRGP-cre mice (Le et al., 2004); thus, conditional knockout of essential genes with these mice is not likely to cause any detrimental effect in non-ocular tissues.
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Affiliation(s)
- Yun-Zheng Le
- Department of Cell Biology, University of Oklahoma Health Sciences Center, USA
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20
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Bobu C, Craft CM, Masson-Pevet M, Hicks D. Photoreceptor organization and rhythmic phagocytosis in the nile rat Arvicanthis ansorgei: a novel diurnal rodent model for the study of cone pathophysiology. Invest Ophthalmol Vis Sci 2006; 47:3109-18. [PMID: 16799057 PMCID: PMC2933834 DOI: 10.1167/iovs.05-1397] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize rod and cone distribution, organization, and phagocytosis in the diurnal mouse-like rodent Arvicanthis ansorgei. METHODS Retinas of adult A. ansorgei were processed for histology, electron microscopy and immunohistochemistry using rod- and mouse cone-specific antibodies. For phagocytosis studies, retinas were sampled every 3 hours under a 12-hour light-dark cycle and processed for double-label immunohistochemistry. The number of phagosomes in the retinal pigmented epithelium were quantified with a morphometric system. RESULTS A. ansorgei retinas were composed of 33% cones and 67% rods, approximately 10 times more cones than mice and rats. Cones were arranged in two cell layers at the scleral surface, distributed uniformly across the entire retina. Cone arrestin was distributed throughout the dark-adapted cones, from outer segments to synapses, whereas short- and mid-wavelength cone opsins were restricted to outer segments. Short-wavelength cone density was mapped in wholemounted retinas, in a significantly higher number in the central region. Rhodopsin immunopositive (rod) phagosomes showed a small peak late in the dark phase, then a large burst 1 to 2 hours after light onset, after decreasing to low baseline levels by 12 AM. Mid-wavelength cone opsin immunopositive (cone) phagosomes were 10 times less numerous than rods, and demonstrated a broad peak 1 to 2 hours after light onset. CONCLUSIONS The diurnal rodent A. ansorgei possesses a large number of cones, organized in a strict anatomic array. Rod and cone outer segment phagocytosis and shedding can be monitored simultaneously and show similar profiles but different amplitudes. This species may constitute a valuable novel animal model for investigating cone pathophysiology.
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Affiliation(s)
- Corina Bobu
- Laboratoire de Neurobiologie des Rythmes, Université Louis Pasteur, Strasbourg, France
| | - Cheryl M. Craft
- Mary D. Allen Laboratory for Vision Research, Doheny Eye Institute, Los Angeles, California
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Mireille Masson-Pevet
- Laboratoire de Neurobiologie des Rythmes, Université Louis Pasteur, Strasbourg, France
| | - David Hicks
- Laboratoire de Neurobiologie des Rythmes, Université Louis Pasteur, Strasbourg, France
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21
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Williams GA, Daigle KA, Jacobs GH. Rod and cone function in coneless mice. Vis Neurosci 2006; 22:807-16. [PMID: 16469189 DOI: 10.1017/s095252380522610x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Accepted: 07/07/2005] [Indexed: 11/07/2022]
Abstract
Transgenic coneless mice were initially developed to study retinal function in the absence of cones. In coneless mice created by expressing an attenuated diphtheria toxin under the control of flanking sequences from the human L-cone opsin gene, a small number of cones (3-5% of the normal complement) survive in a retina that otherwise appears structurally quite normal. These cones predominantly ( approximately 87% of the total) contain UV-sensitive photopigment. ERG recordings, photoreceptor labeling, and behavioral measurements were conducted on coneless and wild-type mice to better understand how the nature of this alteration in receptor complement impacts vision. Signals from the small residual population of UV cones are readily detected in the flicker ERG where they yield signal amplitudes at saturation that are roughly proportional to the number of surviving cones. Behavioral measurements show that rod-based vision in coneless mice does not differ significantly from that of wild-type mice, nor does their rod system show any evidence of age-related deterioration. Coneless mice are able to make accurate rod-based visual discriminations at light levels well in excess of those required to reach cone threshold in wild-type mice.
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Affiliation(s)
- Gary A Williams
- Neuroscience Research Institute and Department of Psychology, University of California, Santa Barbara, 93106, USA
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22
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Kaisho Y, Watanabe T, Nakata M, Yano T, Yasuhara Y, Shimakawa K, Mori I, Sakura Y, Terao Y, Matsui H, Taketomi S. Transgenic rats overexpressing the human MrgX3 gene show cataracts and an abnormal skin phenotype. Biochem Biophys Res Commun 2005; 330:653-7. [PMID: 15809047 DOI: 10.1016/j.bbrc.2005.03.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Indexed: 11/23/2022]
Abstract
The human MrgX3 gene, belonging to the mrgs/SNSRs (mas related genes/sensory neuron specific receptors) family, was overexpressed in transgenic rats using the actin promoter. Two animal lines showed cataracts with liquification/degeneration and swelling of the lens fiber cells. The transient epidermal desquamation was observed in line with higher gene expression. Histopathology of the transgenic rats showed acanthosis and focal parakeratosis. In the epidermis, there was an increase in cellular keratin 14, keratin 10, and loricrin, as well as PGP 9.5 in innervating nerve fibers. These phenotypes accompanied an increase in the number of proliferating cells. These results suggest that overexpression of the human MrgX3 gene causes a disturbance of the normal cell-differentiation process.
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Affiliation(s)
- Yoshihiko Kaisho
- Pharmacology Research Laboratories I, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Osaka, Japan.
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Plafker SM, Plafker KS, Weissman AM, Macara IG. Ubiquitin charging of human class III ubiquitin-conjugating enzymes triggers their nuclear import. ACTA ACUST UNITED AC 2004; 167:649-59. [PMID: 15545318 PMCID: PMC2172591 DOI: 10.1083/jcb.200406001] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Ubiquitin is a small polypeptide that is conjugated to proteins and commonly serves as a degradation signal. The attachment of ubiquitin (Ub) to a substrate proceeds through a multi-enzyme cascade involving an activating enzyme (E1), a conjugating enzyme (E2), and a protein ligase (E3). We previously demonstrated that a murine E2, UbcM2, is imported into nuclei by the transport receptor importin-11. We now show that the import mechanism for UbcM2 and two other human class III E2s (UbcH6 and UBE2E2) uniquely requires the covalent attachment of Ub to the active site cysteine of these enzymes. This coupling of E2 activation and transport arises from the selective interaction of importin-11 with the Ub-loaded forms of these enzymes. Together, these findings reveal that Ub charging can function as a nuclear import trigger, and identify a novel link between E2 regulation and karyopherin-mediated transport.
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Affiliation(s)
- Scott M Plafker
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Wu J, Peachey NS, Marmorstein AD. Light-evoked responses of the mouse retinal pigment epithelium. J Neurophysiol 2003; 91:1134-42. [PMID: 14614107 PMCID: PMC2897140 DOI: 10.1152/jn.00958.2003] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In response to light, the retinal pigment epithelium (RPE) generates a series of slow potentials that can be recorded as the c-wave, fast oscillation (FO), and light peak (LP) of the electroretinogram (ERG). As these potentials can be related to specific cellular events, they provide information about RPE function and how that may be altered by disease or experimental manipulation. In the present study we describe a noninvasive means for recording the light-evoked responses of the mouse RPE and use this to define the stimulus-response properties of the major components in three inbred strains of mice (BALBc/ByJ, C57BL/6J, and 129/SvJ) and two mouse mutants that reduce activity in the rod pathway. All of the major ERG components generated by the RPE are readily measured in the mouse. In albino strains (BALBc/ByJ and 129/SvJ) the intensity-response functions for the c-wave, FO, and LP are shifted toward lower intensities in comparison to those for C57BL/6J mice. Each of these components was markedly reduced in mice lacking transducin in which rod phototransduction is interrupted, indicating that they reflect primarily rod photoreceptor activity. All components were observed in no b-wave (nob) mutant mice, indicating that inner retinal activity does not make a major contribution to these potentials. Further studies of mutant mice will allow us to define the functional consequences of gene manipulation on RPE function and to evaluate specific hypotheses regarding the generation of ERG components.
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Affiliation(s)
- Jiang Wu
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland 44195, USA
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25
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Peachey NS, Quiambao AB, Xu X, Pardue MT, Roveri L, McCall MA, Al-Ubaidi MR. Loss of bipolar cells resulting from the expression of bcl-2 directed by the IRBP promoter. Exp Eye Res 2003; 77:477-83. [PMID: 12957146 DOI: 10.1016/s0014-4835(03)00149-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have recently noted marked reductions in the electroretinographic (ERG) b-wave in HIBA transgenic mice expressing bcl-2 under control of the human IRBP promoter. These electrophysiological results are unexpected as this promoter has been shown to specifically target transgene expression to the rod and cone photoreceptors. Here, we have carried out a series of studies to better understand this result. ERGs were recorded from three lines of HIBA transgenic mice. Mice with higher levels of transgene expression developed progressive photoreceptor degeneration, and an associated reduction in the ERG a-wave. These higher-expressing lines also exhibited a severe reduction in the ERG b-wave that affected both rod- and cone-mediated responses. These mice were mated to L7 transgenic mice, which express beta-galactosidase in bipolar cells. In double transgenic mice, the ERG b-wave reduction was associated with a decrease in the number of bipolar cells in the inner retina. These results indicate that bcl-2, targeted to photoreceptors, can induce bipolar cell degeneration, and indicate that the potential benefit for bcl-2 in treating hereditary retinal disease appears limited.
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Affiliation(s)
- Neal S Peachey
- Cole Eye Institute, (i-31), Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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26
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Ball SL, Gregg RG. Using mutant mice to study the role of voltage-gated calcium channels in the retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 514:439-50. [PMID: 12596937 DOI: 10.1007/978-1-4615-0121-3_26] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Neuronal voltage-gated calcium channels (VGCCs) are critical to numerous cellular functions including synaptogenesis and neurotransmitter release. Mutations in individual subunits of VGCCs are known to result in a wide array of neurological disorders including episodic ataxia, epilepsy, and migraines. The characterization of these disorders has focused on channel function within the brain. However, a defect in the retina-specific alpha1F subunit of an L-type VGCC results is a loss of visual sensitivity or the incomplete form of X-linked congenital stationary night blindness (CSNB2). Based on the electroretinographic phenotype of these patients this channel type is localized to the axon terminal of photoreceptor cells and results in a loss of signal transmission from photoreceptors to bipolar cells. A mouse with a deletion of the beta2 subunit of VGCCs in the central nervous system was recently shown to have a similar phenotype as CSNB2 patients. The identification of the role of VGCCs in this disorder highlights the potential association of other VGCC mutations with retinal disorders. The study of the role of these channels in normal retinal function may also be elucidated by the characterization of retinal structure and visual function in the numerous knockout, transgenic, and naturally occurring mouse mutants currently available.
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Affiliation(s)
- Sherry L Ball
- Research Service, Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA
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Abstract
The mouse has become a key animal model for ocular research. This situation reflects the fact that genes implicated in human retinal disorders or in mammalian retinal function may be readily manipulated in the mouse. Visual electrophysiology provides a means to examine retinal function in mutant mice, and stimulation and recording protocols have been developed that allow the activity of many classes of retinal neurons to be examined and which take into account unique features of the mouse retina. Here, we review the mouse visual electrophysiology literature, covering techniques used to record the mouse electroretinogram and visual evoked potential, and how these have been applied to characterize the functional implications of gene mutation or manipulation in the mouse retina.
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Affiliation(s)
- Neal S Peachey
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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28
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Dong CJ, Hare WA. Temporal modulation of scotopic visual signals by A17 amacrine cells in mammalian retina in vivo. J Neurophysiol 2003; 89:2159-66. [PMID: 12686583 DOI: 10.1152/jn.01008.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined function of the feedback pathway from A17 GABAergic amacrine cells to rod bipolar cells (A17 feedback), a critically located inhibitory circuit in the classic rod pathway of the mammalian retina whose role in processing of scotopic visual information is still poorly understood. We show evidence that this A17 feedback has a profound influence on the temporal properties of rod-driven postphotoreceptoral responses (assessed with the scotopic electroretinogram b-wave). Application of a GABA(c) antagonist prolonged preferentially the decay of the scotopic b-wave. The degree of prolongation increased as the light intensity decreased. Application of selective GABA(a) antagonists accelerated the kinetics of the scotopic b-wave. This effect was abolished when the GABA(c) antagonist was coapplied. Selective ablation of A17 cells mimicked the action of the GABA(c) antagonist. In A17 cell-ablated retinas, the GABA(c) antagonist was no longer very effective to slow the decay of the scotopic b-wave. Thus the A17 feedback, activated by light stimulation and mediated mainly by the GABA(c) receptors, makes the scotopic b-wave more transient by accelerating preferentially its decay. The strength of the feedback can be modulated by GABA(a) receptor-mediated inhibition and by light intensity. Our results also suggest that in the mammalian retina the feedback may be a novel mechanism that contributes postphotoreceptorally to the termination of rod signals, especially those elicited by very dim light stimuli.
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Affiliation(s)
- Cun-Jian Dong
- Department of Biological Sciences, Allergan Pharmaceuticals, Irvine, California 92612, USA.
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Elimination of the rho1 subunit abolishes GABA(C) receptor expression and alters visual processing in the mouse retina. J Neurosci 2002. [PMID: 12019334 DOI: 10.1523/jneurosci.22-10-04163.2002] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inhibition is crucial for normal function in the nervous system. In the CNS, inhibition is mediated primarily by the amino acid GABA via activation of two ionotropic GABA receptors, GABA(A) and GABA(C). GABA(A) receptor composition and function have been well characterized, whereas much less is known about native GABA(C) receptors. Differences in molecular composition, anatomical distributions, and physiological properties strongly suggest that GABA(A) receptors and GABA(C) receptors have distinct functional roles in the CNS. To determine the functional role of GABA(C) receptors, we eliminated their expression in mice using a knock-out strategy. Although native rodent GABA(C) receptors are composed of rho1 and rho2 subunits, we show that after rho1 subunit expression was selectively eliminated there was no GABA(C) receptor expression. We assessed GABA(C) receptor function in the retina because GABA(C) receptors are highly expressed on the axon terminals of rod bipolar cells and because this site modulates the visual signal to amacrine and ganglion cells. In GABA(C)rho1 null mice, GABA-evoked responses, normally mediated by GABA(C) receptors, were eliminated, and signaling from rod bipolar cells to third order cells was altered. These data demonstrate that elimination of the GABA(C)rho1 subunit, via gene targeting, results in the absence of GABA(C) receptors in the retina and selective alterations in normal visual processing.
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Krishna VR, Alexander KR, Peachey NS. Temporal properties of the mouse cone electroretinogram. J Neurophysiol 2002; 87:42-8. [PMID: 11784728 DOI: 10.1152/jn.00489.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine the temporal response characteristics of the mouse cone electroretinogram (ERG), we recorded responses to high contrast sinusoidal stimuli ranging from 2 to 52 Hz. The largest response amplitudes obtained from wild-type (WT) mice occurred at stimulus frequencies below 10 Hz, and cone ERG amplitude declined progressively with increasing stimulus frequency above that level. In comparison, human responses recorded under the same stimulus and recording conditions displayed maximal responses to stimulus frequencies near 4 and 40 Hz, and a pronounced dip at 12 Hz. Responses were also obtained from nob (no b-wave) mice, which lack ERG contributions from depolarizing bipolar cells (DBCs). At low temporal frequencies, nob cone ERGs were smaller than those of WT mice and had a different waveform. As temporal frequency increased, nob and WT responses became more similar and came into register at the highest temporal frequencies. To evaluate the contribution of the DBC pathway to the mouse cone ERG, nob responses were vector-subtracted from those of WT mice. The derived DBC response was maximal at low stimulus frequencies and fell sharply as stimulus frequency increased. These results indicate that the mouse cone ERG is more linear than the primate response and that the temporal response of the mouse outer retina is tuned to much lower frequencies than that of primate.
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Affiliation(s)
- Vivek R Krishna
- Research Service, Cleveland Veterans Administration Medical Center, Cleveland, Ohio 44106, USA
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Quiambao AB, Tan E, Chang S, Komori N, Naash MI, Peachey NS, Matsumoto H, Ucker DS, Al-Ubaidi MR. Transgenic Bcl-2 expressed in photoreceptor cells confers both death-sparing and death-inducing effects. Exp Eye Res 2001; 73:711-21. [PMID: 11747371 DOI: 10.1006/exer.2001.1083] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine its potential role within the retina as a modulator of cell death and photoreceptor degeneration, bcl-2 expression was targeted to the photoreceptors of transgenic mice by the human IRBP promoter. Three transgenic families were established, with levels of transgene expression between 0.2 and two-fold relative to that of endogenous bcl-2. The effect of bcl-2 expression on genetically programmed photoreceptor degeneration was evaluated by crossing these transgenic mice with mice that develop a rapid degeneration of rod photoreceptors due to expression of a distinct transgene, SV40 T antigen (Tag). Transgenic Bcl-2 was localized to photoreceptor inner segments and was capable of abrogating the activation of caspase activity and the resulting cell death associated with ectopic expression of Tag. However, Bcl-2 itself ultimately caused photoreceptor cell death and retinal degeneration. Several proteins not expressed normally in Tag or other transgenic retinas undergoing photoreceptor degeneration were induced in the Bcl-2 transgenic retinas. Analysis by mass spectroscopy identified one of these proteins as alphaA-crystallin, a member of a protein family that associates with cellular stress. Since Bcl-2 can promote as well as spare cell death in the same photoreceptor population, its potential utility in ameliorating photoreceptor death in human hereditary blinding disorders is compromised.
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Affiliation(s)
- A B Quiambao
- Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine, Chicago, IL 60612, USA
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Abstract
PURPOSE To define the physiological and structural changes that may accompany aging in the normal mouse retina. METHODS C57BL/6 mice were maintained under cyclic light for either 2, 6, or 12 months. After rod- and cone-mediated corneal electroretinograms (ERG's) were recorded from anesthetized animals, the retinal structure was quantitatively examined. Photoreceptor cell density was measured within 100-microm regions of the central superior and inferior retina. Cone photoreceptor subtypes were identified by immunocytochemistry. RESULTS The amplitudes of rod- and cone-mediated ERG's were reduced in older mice, although the overall ERG wave-form did not change appreciably and implicit times were not changed in an age-dependent fashion. In comparison, there was no significant age-related decline in rod or cone photoreceptor density. CONCLUSIONS The amplitude of the mouse ERG declines with age. This change does not appear to reflect a change in the structural integrity of the photoreceptor cells. In functional studies of murine models of late-onset retinal disorders, it will be important to take these changes into consideration.
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Affiliation(s)
- C Li
- Department of Biological Sciences, University of Illinois at Chicago, USA
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Ren JC, Stubbs EB, Matthes MT, Yasumura D, Naash MI, LaVail MM, Peachey NS. Retinal degeneration in the nervous mutant mouse. IV. Inner retinal changes. Exp Eye Res 2001; 72:243-52. [PMID: 11180973 DOI: 10.1006/exer.2000.0961] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have recently noted that the inner nuclear layer (INL) and the inner plexiform layer (IPL) were significantly thinner in mice homozygous for the nervous defect (nr / nr) than in control (nr /+ or +/+) littermates. Here, we have carried out a series of anatomical studies to further understand these inner retinal changes. At postnatal day (P) 13, there was no difference in the inner retina between nervous and control mice, while a significant difference was observed at P30. Similar changes were not seen in other mouse models of photoreceptor degeneration. There was a significant reduction in the density of cells in the INL that were stained by antibodies against the inhibitory neurotransmitters GABA and glycine. These results indicate that the nervous defect causes a degeneration of one or more sub-types of amacrine cells, in addition to the loss of cerebellar Purkinje cells and retinal photoreceptors that is known to occur in these mutant animals. Finally, evidence is provided that photoreceptors die by an apoptotic pathway in nervous mice.
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Affiliation(s)
- J C Ren
- Program in Neuroscience, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
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Ball SL, Lindberg FP, Lagenaur CF, Peachey NS. Electroretinograms remain normal in mice lacking a synapse associated protein. Neurosci Lett 2001; 298:111-4. [PMID: 11163290 DOI: 10.1016/s0304-3940(00)01743-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Integrin-associated protein (IAP) is normally localized to the synapse rich plexiform layers of the mammalian retina. In other neuronal systems, IAP and its ligand, P84, have been implicated in synaptic function. Previously, an abnormal distribution of P84 was noted in the IAP-null retina. To examine the potential role of IAP in the function of the retinal outer plexiform layer, we recorded electroretinograms (ERGs) from IAP-null mice and wild-type littermates. Under a wide range of stimulus conditions, there was no difference between the responses of these two groups, including ERG components that reflect post-receptoral activity. These results indicate that IAP and/or P84 may not be critical for the development and maintenance of the photoreceptor-to-bipolar cell synapse.
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Affiliation(s)
- S L Ball
- Research Service, Hines VA Hospital, Hines IL 60141, USA.
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