1
|
Du R, Wang P, Tian N. CD3ζ-Mediated Signaling Protects Retinal Ganglion Cells in Glutamate Excitotoxicity of the Retina. Cells 2024; 13:1006. [PMID: 38920637 PMCID: PMC11201742 DOI: 10.3390/cells13121006] [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: 03/30/2024] [Revised: 05/28/2024] [Accepted: 06/06/2024] [Indexed: 06/27/2024] Open
Abstract
Excessive levels of glutamate activity could potentially damage and kill neurons. Glutamate excitotoxicity is thought to play a critical role in many CNS and retinal diseases. Accordingly, glutamate excitotoxicity has been used as a model to study neuronal diseases. Immune proteins, such as major histocompatibility complex (MHC) class I molecules and their receptors, play important roles in many neuronal diseases, while T-cell receptors (TCR) are the primary receptors of MHCI. We previously showed that a critical component of TCR, CD3ζ, is expressed by mouse retinal ganglion cells (RGCs). The mutation of CD3ζ or MHCI molecules compromises the development of RGC structure and function. In this study, we investigated whether CD3ζ-mediated molecular signaling regulates RGC death in glutamate excitotoxicity. We show that mutation of CD3ζ significantly increased RGC survival in NMDA-induced excitotoxicity. In addition, we found that several downstream molecules of TCR, including Src (proto-oncogene tyrosine-protein kinase) family kinases (SFKs) and spleen tyrosine kinase (Syk), are expressed by RGCs. Selective inhibition of an SFK member, Hck, or Syk members, Syk or Zap70, significantly increased RGC survival in NMDA-induced excitotoxicity. These results provide direct evidence to reveal the underlying molecular mechanisms that control RGC death under disease conditions.
Collapse
Affiliation(s)
- Rui Du
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
| | - Ping Wang
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
| | - Ning Tian
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84132, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84132, USA
- Veterans Affairs Medical Center, Salt Lake City, UT 84148, USA
| |
Collapse
|
2
|
ElSayed MH, Elbayoumi KS, Eladl MA, Mohamed AAK, Hegazy A, El-Sherbeeny NA, Attia MA, Hisham FA, Saleh MAK, Elaskary A, Morsi K, Mustsafa AMA, Enan ET, Zaitone SA. Memantine mitigates ROS/TXNIP/NLRP3 signaling and protects against mouse diabetic retinopathy: Histopathologic, ultrastructural and bioinformatic studies. Biomed Pharmacother 2023; 163:114772. [PMID: 37116352 DOI: 10.1016/j.biopha.2023.114772] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/17/2023] [Accepted: 04/22/2023] [Indexed: 04/30/2023] Open
Abstract
Diabetic retinopathy (DRET) triggers vision loss in adults, however, little therapeutic options are existing. Memantine is an anti-Alzheimer drug that antagonizes the activity of glutamate at N-methyl-D-aspartate (NMDA) receptors. Glutamate and thioredoxin-interacting protein (TXNIP) are known to be overexpressed in diabetic retinas and can produce activation of NOD-like receptor protein 3 (NLRP3) with subsequent secretion of interlukin-1β. This study repurposed memantine for its neuroprotective effect in experimental DRET and tested its impact on ROS/TXNIP/NLRP3. In addition, KEGG pathway database and STRING database identified the protein-protein interaction between glutamate receptors and TXNIP/NLRP3. Male Swiss albino mice received alloxan (180 mg/kg) to induce DRET. After 9 weeks, we divided the mice into groups: (a) saline, (ii) DRET, (iii and iv) DRET + oral memantine (5 or 10 mg per kg) for 28 days. Then, mice were euthanized, and eyeballs were removed. Retinal samples were utilized for biochemical, histopathological, and electron microscopy studies. Retinal levels of glutamate, TXNIP, NLRP3 and interlukin-1β were estimated using ELISA technique as well as retinal malondialdehyde. Histopathological and ultrastructural examination demonstrated that oral memantine attenuated vacuolization and restored normal retinal cell layers. Moreover, memantine reduced TXNIP, NLRP3, interleukin-1β and MDA concentrations. These results provide evidence demonstrating memantine' efficacy in alleviating DRET via suppressing reactive oxygen species/TXNIP/NLRP3 signaling cascade. Therefore, memantine might serve as a potential therapy for retinopathy after adequate clinical research.
Collapse
Affiliation(s)
- Mohammed H ElSayed
- Department of Physiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
| | - Khaled S Elbayoumi
- Department of Human Anatomy and Embryology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt; Department of Basic medical Sciences, Ibn Sina University for Medical Sciences, Amman 16197, Jordan
| | - Mohamed Ahmed Eladl
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Abeer A K Mohamed
- Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Ann Hegazy
- Department of Clinical Pathology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Nagla A El-Sherbeeny
- Department of Clinical Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Mohammed A Attia
- Department of Clinical Pharmacology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt; Department of Basic medical sciences, College of Medicine, AlMaarefa University, 71666, Riyadh 11597, Saudi Arabia
| | - Fatma Azzahraa Hisham
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Mohamed A K Saleh
- Ophthalmology Department, Al-Asher Asyut Faculty of Medicine for Men, Asyut, Egypt
| | - Abdelhakeem Elaskary
- Ophthalmology Department, Al-Asher Asyut Faculty of Medicine for Men, Asyut, Egypt
| | - Khaled Morsi
- Department of Anesthesia Technology, College of Applied Medical Sciences in Jubail, Imam Abdulrahman Bin Faisal University, Jubail 35811, Saudi Arabia.
| | - Amna M A Mustsafa
- Department of Pediatric Nursing, Jazan University, Jazan 45142, Saudi Arabia
| | - Eman T Enan
- Department of Basic medical sciences, College of Medicine, AlMaarefa University, 71666, Riyadh 11597, Saudi Arabia; Department of Pathology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Sawsan A Zaitone
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt.
| |
Collapse
|
3
|
MicroRNA-150 (miR-150) and Diabetic Retinopathy: Is miR-150 Only a Biomarker or Does It Contribute to Disease Progression? Int J Mol Sci 2022; 23:ijms232012099. [PMID: 36292956 PMCID: PMC9603433 DOI: 10.3390/ijms232012099] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/18/2022] Open
Abstract
Diabetic retinopathy (DR) is a chronic disease associated with diabetes mellitus and is a leading cause of visual impairment among the working population in the US. Clinically, DR has been diagnosed and treated as a vascular complication, but it adversely impacts both neural retina and retinal vasculature. Degeneration of retinal neurons and microvasculature manifests in the diabetic retina and early stages of DR. Retinal photoreceptors undergo apoptosis shortly after the onset of diabetes, which contributes to the retinal dysfunction and microvascular complications leading to vision impairment. Chronic inflammation is a hallmark of diabetes and a contributor to cell apoptosis, and retinal photoreceptors are a major source of intraocular inflammation that contributes to vascular abnormalities in diabetes. As the levels of microRNAs (miRs) are changed in the plasma and vitreous of diabetic patients, miRs have been suggested as biomarkers to determine the progression of diabetic ocular diseases, including DR. However, few miRs have been thoroughly investigated as contributors to the pathogenesis of DR. Among these miRs, miR-150 is downregulated in diabetic patients and is an endogenous suppressor of inflammation, apoptosis, and pathological angiogenesis. In this review, how miR-150 and its downstream targets contribute to diabetes-associated retinal degeneration and pathological angiogenesis in DR are discussed. Currently, there is no effective treatment to stop or reverse diabetes-caused neural and vascular degeneration in the retina. Understanding the molecular mechanism of the pathogenesis of DR may shed light for the future development of more effective treatments for DR and other diabetes-associated ocular diseases.
Collapse
|
4
|
Boccuni I, Fairless R. Retinal Glutamate Neurotransmission: From Physiology to Pathophysiological Mechanisms of Retinal Ganglion Cell Degeneration. Life (Basel) 2022; 12:638. [PMID: 35629305 PMCID: PMC9147752 DOI: 10.3390/life12050638] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 12/12/2022] Open
Abstract
Glutamate neurotransmission and metabolism are finely modulated by the retinal network, where the efficient processing of visual information is shaped by the differential distribution and composition of glutamate receptors and transporters. However, disturbances in glutamate homeostasis can result in glutamate excitotoxicity, a major initiating factor of common neurodegenerative diseases. Within the retina, glutamate excitotoxicity can impair visual transmission by initiating degeneration of neuronal populations, including retinal ganglion cells (RGCs). The vulnerability of RGCs is observed not just as a result of retinal diseases but has also been ascribed to other common neurodegenerative and peripheral diseases. In this review, we describe the vulnerability of RGCs to glutamate excitotoxicity and the contribution of different glutamate receptors and transporters to this. In particular, we focus on the N-methyl-d-aspartate (NMDA) receptor as the major effector of glutamate-induced mechanisms of neurodegeneration, including impairment of calcium homeostasis, changes in gene expression and signalling, and mitochondrial dysfunction, as well as the role of endoplasmic reticular stress. Due to recent developments in the search for modulators of NMDA receptor signalling, novel neuroprotective strategies may be on the horizon.
Collapse
Affiliation(s)
- Isabella Boccuni
- Institute for Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany;
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany;
- Clinical Cooperation Unit (CCU) Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| |
Collapse
|
5
|
Min J, Zeng T, Roux M, Lazar D, Chen L, Tudzarova S. The Role of HIF1α-PFKFB3 Pathway in Diabetic Retinopathy. J Clin Endocrinol Metab 2021; 106:2505-2519. [PMID: 34019671 PMCID: PMC8372643 DOI: 10.1210/clinem/dgab362] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Indexed: 12/13/2022]
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness for adults in developed countries. Both microvasculopathy and neurodegeneration are implicated in mechanisms of DR development, with neuronal impairment preceding microvascular abnormalities, which is often underappreciated in the clinic. Most current therapeutic strategies, including anti-vascular endothelial growth factor (anti-VEGF)-antibodies, aim at treating the advanced stages (diabetic macular edema and proliferative diabetic retinopathy) and fail to target the neuronal deterioration. Hence, new therapeutic approach(es) intended to address both vascular and neuronal impairment are urgently needed. The hypoxia-inducible factor 1α (HIF1α)-6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) pathway is critically implicated in the islet pathology of diabetes. Recent evidence highlighted the pathway relevance for pathologic angiogenesis and neurodegeneration, two key aspects in DR. PFKFB3 is key to the sprouting angiogenesis, along with VEGF, by determining the endothelial tip-cell competition. Also, PFKFB3-driven glycolysis compromises the antioxidative capacity of neurons leading to neuronal loss and reactive gliosis. Therefore, the HIF1α-PFKFB3 signaling pathway is unique as being a pervasive pathological component across multiple cell types in the retina in the early as well as late stages of DR. A metabolic point-of-intervention based on HIF1α-PFKFB3 targeting thus deserves further consideration in DR.
Collapse
Affiliation(s)
- Jie Min
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Tianshu Zeng
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Margaretha Roux
- Groote Schuur and Red Cross Children’s Hospital, University of Cape Town, South Africa
| | - David Lazar
- Lazar Retina Ophthalmology, Los Angeles, CA, USA
| | - Lulu Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Lulu Chen, PhD, Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Ave, Wuhan, Hubei, 430022, China.
| | - Slavica Tudzarova
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Correspondence: Slavica Tudzarova, PhD, Larry Hillblom Islet Research Center, University of California Los Angeles, 10833 Le Conte Ave, CHS 33-165, Los Angeles, CA 90095, USA.
| |
Collapse
|
6
|
El-Mansi AA, Al-Kahtani MA, Rady AM, El-Bealy EA, Al-Asmari AM. Vitamin A and Daucus carota root extract mitigate STZ-induced diabetic retinal degeneration in Wistar albino rats by modulating neurotransmission and downregulation of apoptotic pathways. J Food Biochem 2021; 45:e13688. [PMID: 33687088 DOI: 10.1111/jfbc.13688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/14/2021] [Accepted: 02/21/2021] [Indexed: 12/17/2022]
Abstract
The objective of our study was to explore the deleterious effects of diabetes on the visual functions of the retina and to address whether the administration of vitamin A and carrot root extract (CE) confer retinal protection in hyperglycemic rats via modulation of oxidative stress, biochemical alternations, and retinal neurotransmission. Fifty male Wistar albino rats weighing 180 ± 12.41 g were randomized into five groups (n = 10): controls, diabetic group (injected with 40 mg/kg dissolved in 0.1 sodium citrate buffer), diabetic group treated with vitamin A (2,500 IU/kg, low dose), diabetic group treated with vitamin (5,000 IU/kg, high dose), and diabetic groups administered CE (200 mg/kg/every other day). Our findings showed that, compared to controls, diabetic rats showed a significant decrease in their retinal thickness, increased apoptotic ganglion cells, and a noticeable degeneration of their synaptic layers. The inner retina displayed increased activity of neovascularization; however, the outer retina exhibited vacuolar degeneration of the photoreceptor cell layer. Our biochemical assessments showed reduced levels of CAT, SOD, and GST along with increased lipid peroxidation. Concurrently, cellular angiogenic and stress markers were significantly elevated associated with increased apoptotic activities as evidenced by increased expressions of annexin-V and PARP. Furthermore, the neurotransmitter content of the retina was altered in diabetic rats compared to controls and diabetic-treated groups. Paradoxically, vitamin A and CE supplementation attenuate these retinal insults in diabetic animals and normalized aforementioned assayed parameters; evidencing that both treatments exerted ameliorative impacts and restored visual functions by diminishing oxidative stress and neuronal degeneration. PRACTICAL APPLICATIONS: Diabetes is a complex disease that involves various physiological perturbations especially visual functions. In our study, we showed that vitamin A and carrot root extract (CE) confer remarkable protection against retinal degeneration in STZ-induced diabetic rats. Our findings showed that the chemical and phytochemical ingredients of the vitamin A and CE substantially attenuated the histopathological changes, oxidative stress, inflammatory reactions, and cellular death in diabetic rats. These favorable changes are attributable to the high content of retinoic acid, carotenoids, and phenolic compounds that effectively regulates the production of visual pigments, increases the antioxidant defense system, and diminishes the pro-inflammatory and apoptotic pathways. Thus, the nutritional values of vitamin A and CE represent promising therapeutic choices to mitigate the retinal-induced diabetic insults.
Collapse
Affiliation(s)
- Ahmed A El-Mansi
- Biology Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia.,Zoology Department, Faculty of Science, Mansoura University, Mansoura, Egypt
| | - M A Al-Kahtani
- Biology Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia
| | - Ahmed M Rady
- Biology Department, Faculty of Science, King Saud University, Riyadh, Saudi Arabia
| | - Eman A El-Bealy
- Biology Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia
| | - A M Al-Asmari
- Biology Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia
| |
Collapse
|
7
|
Abo El Gheit RE, Soliman NA, Badawi GA, Madi NM, El-Saka MH, Badr SM, Emam MN. Retinoprotective effect of agmatine in streptozotocin-induced diabetic rat model: avenues for vascular and neuronal protection : Agmatine in diabetic retinopathy. J Physiol Biochem 2021; 77:305-320. [PMID: 33635523 DOI: 10.1007/s13105-021-00799-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 02/08/2021] [Indexed: 12/20/2022]
Abstract
Diabetic retinopathy (DR) is the most common diabetic neurovascular complication, and the leading cause of preventable blindness among working-age individuals. Recently, agmatine, the endogenous decarboxylated L-arginine, has gained attention as a pleiotropic agent that modulates the diabetes-associated decline in quality of life, and exhibited varied protective biological effects. Diabetes was induced by a single streptozotocin (STZ, 50 mg/kg, i.p.) injection. When diabetes was verified, the animals were randomly allocated into three groups (16 rat each); diabetic, agmatine-treated diabetic (1 mg/kg, daily, for 12 weeks), and control group. Blood glucose homeostasis, retinal redox status, apoptotic parameters, nitric oxide synthase (NOS), nitric oxide (NO), vascular endothelial growth factor (VEGF), glutamate, glutamine, glutamine synthase (GS) activity, nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), and mitogen-activated protein kinase (MAPKs) pathways were assayed biochemically. Retinal vascular permeability was measured. Retinal morphology was evaluated by hematoxylin and eosin staining. Retinal N-methyl-D-aspartic acid receptor1 (NMDAR1) and glutamate aspartate transporter (GLAST) mRNA were quantified. Glucose transporter 1, pro-caspase3, and glial fibrillary acidic protein (GFAP) expression were quantified by immunohistochemistry. Chronic agmatine treatment abrogated STZ-induced retinal neurodegeneration features including gliosis, and neuronal apoptosis, restored retinal vascular permeability, mostly through antioxidant, anti-apoptotic capacity, abolishing glutamate excitotoxicity, modulating the activity of NMDARs, MAPKs/NFκB, and NOS/NO pathways. By restoring the molecular and functional background of retinal neurovascular homeostatic balance, agmatine would be appropriate therapeutic option acting upstream of the DR, impeding its progression.
Collapse
Affiliation(s)
| | - Nema A Soliman
- Medical Biochemistry Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Ghada A Badawi
- Pharmacology and Toxicology Department, Faculty of Pharmacy and Pharmaceutical Industries, Sinai University, El-Arish, Egypt
| | - Nermin M Madi
- Physiology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mervat H El-Saka
- Physiology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Shimaa M Badr
- Histology Departments, Tanta University, Tanta, Egypt
| | - Marwa N Emam
- Physiology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| |
Collapse
|
8
|
Flood MD, Wellington AJ, Cruz LA, Eggers ED. Early diabetes impairs ON sustained ganglion cell light responses and adaptation without cell death or dopamine insensitivity. Exp Eye Res 2020; 200:108223. [PMID: 32910942 DOI: 10.1016/j.exer.2020.108223] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/17/2020] [Accepted: 09/03/2020] [Indexed: 10/23/2022]
Abstract
Retinal signaling under dark-adapted conditions is perturbed during early diabetes. Additionally, dopamine, the main neuromodulator of retinal light adaptation, is diminished in diabetic retinas. However, it is not known if this dopamine deficiency changes how the retina responds to increased light or dopamine. Here we determine whether light adaptation is impaired in the diabetic retina, and investigate potential mechanism(s) of impairment. Diabetes was induced in C57BL/6J male mice via 3 intraperitoneal injections of streptozotocin (75 mg/kg) and confirmed by blood glucose levels more than 200 mg/dL. After 6 weeks, whole-cell recordings of light-evoked and spontaneous inhibitory postsynaptic currents (IPSCs) or excitatory postsynaptic currents (EPSCs) were made from rod bipolar cells and ON sustained ganglion cells, respectively. Light responses were recorded before and after D1 receptor (D1R) activation (SKF-38393, 20 μM) or light adaptation (background of 950 photons·μm-2 ·s-1). Retinal whole mounts were stained for either tyrosine hydroxylase and activated caspase-3 or GAD65/67, GlyT1 and RBPMS and imaged. D1R activation and light adaptation both decreased inhibition, but the disinhibition was not different between control and diabetic rod bipolar cells. However, diabetic ganglion cell light-evoked EPSCs were increased in the dark and showed reduced light adaptation. No differences were found in light adaptation of spontaneous EPSC parameters, suggesting upstream changes. No changes in cell density were found for dopaminergic, glycinergic or GABAergic amacrine cells, or ganglion cells. Thus, in early diabetes, ON sustained ganglion cells receive excessive excitation under dark- and light-adapted conditions. Our results show that this is not attributable to loss in number or dopamine sensitivity of inhibitory amacrine cells or loss of dopaminergic amacrine cells.
Collapse
Affiliation(s)
- Michael D Flood
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| | - Andrea J Wellington
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| | - Luis A Cruz
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| | - Erika D Eggers
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| |
Collapse
|
9
|
Bojcevski J, Stojic A, Hoffmann DB, Williams SK, Müller A, Diem R, Fairless R. Influence of retinal NMDA receptor activity during autoimmune optic neuritis. J Neurochem 2020; 153:693-709. [PMID: 32031240 DOI: 10.1111/jnc.14980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/14/2020] [Accepted: 01/27/2020] [Indexed: 12/20/2022]
Abstract
Autoimmune optic neuritis (AON), a model of multiple sclerosis-associated optic neuritis, is accompanied by degeneration of retinal ganglion cells (RGCs) and optic nerve demyelination and axonal loss. In order to investigate the role of N-methyl-d-aspartate (NMDA) receptors in mediating RGC degeneration, upstream changes in the optic nerve actin cytoskeleton and associated deterioration in visual function, we induced AON in Brown Norway rats by immunization with myelin oligodendrocyte glycoprotein. Subsequently, visual acuity was assessed by recording visual evoked potentials and electroretinograms prior to extraction of optic nerves for western blot analysis and retinas for quantification of RGCs. As previously reported, in Brown Norway rats RGC degeneration is observed prior to onset of immune cell infiltration and demyelination of the optic nerves. However, within the optic nerve, destabilization of the actin cytoskeleton could be seen as indicated by an increase in the globular to filamentous actin ratio. Interestingly, these changes could be mimicked by intravitreal injection of glutamate, and similarly blocked by application of the NMDA receptor blocker MK-801, leading us to propose that prior to optic nerve lesion formation, NMDA receptor activation within the retina leads to retinal calcium accumulation, actin destabilization within the optic nerve as well as a deterioration of visual acuity during AON.
Collapse
Affiliation(s)
- Jovana Bojcevski
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Aleksandar Stojic
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Dorit B Hoffmann
- Department of Neurology, Saarland University, Homburg, Germany.,A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Sarah K Williams
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Andreas Müller
- Department of Diagnostic and Interventional Radiology, Saarland University, Homburg, Germany
| | - Ricarda Diem
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| |
Collapse
|
10
|
Christensen I, Lu B, Yang N, Huang K, Wang P, Tian N. The Susceptibility of Retinal Ganglion Cells to Glutamatergic Excitotoxicity Is Type-Specific. Front Neurosci 2019; 13:219. [PMID: 30930737 PMCID: PMC6429039 DOI: 10.3389/fnins.2019.00219] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 02/26/2019] [Indexed: 12/17/2022] Open
Abstract
Retinal ganglion cells (RGCs) are the only output neurons that conduct visual signals from the eyes to the brain. RGC degeneration occurs in many retinal diseases leading to blindness and increasing evidence suggests that RGCs are susceptible to various injuries in a type-specific manner. Glutamate excitotoxicity is the pathological process by which neurons are damaged and killed by excessive stimulation of glutamate receptors and it plays a central role in the death of neurons in many CNS and retinal diseases. The purpose of this study is to characterize the susceptibility of genetically identified RGC types to the excitotoxicity induced by N-methyl-D-aspartate (NMDA). We show that the susceptibility of different types of RGCs to NMDA excitotoxicity varies significantly, in which the αRGCs are the most resistant type of RGCs to NMDA excitotoxicity while the J-RGCs are the most sensitive cells to NMDA excitotoxicity. These results strongly suggest that the differences in the genetic background of RGC types might provide valuable insights for understanding the selective susceptibility of RGCs to pathological insults and the development of a strategy to protect RGCs from death in disease conditions. In addition, our results show that RGCs lose dendrites before death and the sequence of the morphological and molecular events during RGC death suggests that the initial insult of NMDA excitotoxicity might set off a cascade of events independent of the primary insults. However, the kinetics of dendritic retraction in RGCs does not directly correlate to the susceptibility of type-specific RGC death.
Collapse
Affiliation(s)
- Ian Christensen
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Bo Lu
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ning Yang
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Kevin Huang
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ping Wang
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ning Tian
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| |
Collapse
|
11
|
Zafar S, Sachdeva M, Frankfort BJ, Channa R. Retinal Neurodegeneration as an Early Manifestation of Diabetic Eye Disease and Potential Neuroprotective Therapies. Curr Diab Rep 2019; 19:17. [PMID: 30806815 PMCID: PMC7192364 DOI: 10.1007/s11892-019-1134-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW Diabetic retinopathy (DR) is a major cause of visual impairment and blindness throughout the world. Microvascular changes have long been regarded central to disease pathogenesis. In recent years, however, retinal neurodegeneration is increasingly being hypothesized to occur prior to the vascular changes classically associated with DR and contribute to disease pathogenesis. RECENT FINDINGS There is growing structural and functional evidence from human and animal studies that suggests retinal neurodegeneration to be an early component of DR. Identification of new therapeutic targets is an ongoing area of research with several different molecules undergoing testing in animal models for their neuroprotective properties and for possible use in humans. Retinal neurodegeneration may play a central role in DR pathogenesis. As new therapies are developed, it will be important to develop criteria for clinically defining retinal neurodegeneration. A standardization of the methods for monitoring neurodegeneration along with more sensitive means of detecting preclinical damage is also needed.
Collapse
Affiliation(s)
- Sidra Zafar
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD 21287, USA
| | - Mira Sachdeva
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD 21287, USA
| | | | - Roomasa Channa
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD 21287, USA
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
| |
Collapse
|
12
|
Santiago AR, Boia R, Aires ID, Ambrósio AF, Fernandes R. Sweet Stress: Coping With Vascular Dysfunction in Diabetic Retinopathy. Front Physiol 2018; 9:820. [PMID: 30057551 PMCID: PMC6053590 DOI: 10.3389/fphys.2018.00820] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/12/2018] [Indexed: 12/15/2022] Open
Abstract
Oxidative stress plays key roles in the pathogenesis of retinal diseases, such as diabetic retinopathy. Reactive oxygen species (ROS) are increased in the retina in diabetes and the antioxidant defense system is also compromised. Increased ROS stimulate the release of pro-inflammatory cytokines, promoting a chronic low-grade inflammation involving various signaling pathways. An excessive production of ROS can lead to retinal endothelial cell injury, increased microvascular permeability, and recruitment of inflammatory cells at the site of inflammation. Recent studies have started unraveling the complex crosstalk between retinal endothelial cells and neuroglial cells or leukocytes, via both cell-to-cell contact and secretion of cytokines. This crosstalk is essential for the maintenance of the integrity of retinal vascular structure. Under diabetic conditions, an aberrant interaction between endothelial cells and other resident cells of the retina or invading inflammatory cells takes place in the retina. Impairment in the secretion and flow of molecular signals between different cells can compromise the retinal vascular architecture and trigger angiogenesis. In this review, the synergistic contributions of redox-inflammatory processes for endothelial dysfunction in diabetic retinopathy will be examined, with particular attention paid to endothelial cell communication with other retinal cells.
Collapse
Affiliation(s)
- Ana R Santiago
- Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal.,Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | - Raquel Boia
- Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal
| | - Inês D Aires
- Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal
| | - António F Ambrósio
- Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal
| | - Rosa Fernandes
- Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
13
|
Jiang H, Du J, Song J, Li Y, Wu M, Zhou J, Wu S. Loss-of-function mutation of serine racemase attenuates retinal ganglion cell loss in diabetic mice. Exp Eye Res 2018; 175:90-97. [PMID: 29913163 DOI: 10.1016/j.exer.2018.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/14/2018] [Accepted: 06/14/2018] [Indexed: 10/14/2022]
Abstract
Consistent results suggest the promoting roles of serine racemase (SR)/D-serine in retinal neurodegeneration in diabetic retinopathy (DR). However, the direct evidence connecting SR deficiency with retinal neuroprotection in genetic model of diabetes mellitus has not been reported. In this investigation, we explore the effect of absence of functional SR on the degeneration of retinal ganglion cells (RGCs) with a diabetic murine model, Ins2Akita mice. We established a murine strain with double mutation, termed Ins2Akita-Srr, by mating heterozygous Ins2Akita mice with homozygous Srrochre269 mice. Ins2Akita retained less RGC in posterior, middle, and peripheral retinae than the counterpart from non-diabetic sibling mice at the age of five or seven months. Ins2Akita-Srr mice retained more RGC in middle and peripheral--but not in posterior-- retinae than the counterpart from Ins2Akita sibling mice at the age of five months. By contrast, at the age of seven months, Ins2Akita-Srr mice contained more RGC in peripheral, middle, and posterior retinae than the counterpart from Ins2Akita. RGCs were identified with retrograde labeling in vivo or with immunolabeling against a RGC-specific transcription factor, Brn3a, in retinal flat mounts. Correspondingly, the aqueous humor of Ins2Akita-Srr contained less amount of D-serine than sibling Ins2Akita mice. Thus, SR deficiency significantly prevented RGC loss in diabetic mice. We conclude that D-serine is a critical factor in the degeneration of RGC in DR. Targeting SR expression or activity may be a strategy for ameliorating RGC loss in DR.
Collapse
Affiliation(s)
- Haiyan Jiang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China
| | - Jinlin Du
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China
| | - Juan Song
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China
| | - Yanqi Li
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China
| | - Mengjuan Wu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China
| | - Jing Zhou
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China
| | - Shengzhou Wu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, PR China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325003, PR China.
| |
Collapse
|
14
|
Neurodegeneration in diabetic retinopathy: Potential for novel therapies. Vision Res 2017; 139:82-92. [PMID: 28988945 DOI: 10.1016/j.visres.2017.06.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 06/12/2017] [Accepted: 06/14/2017] [Indexed: 11/20/2022]
Abstract
The complex pathology of diabetic retinopathy (DR) affects both vascular and neural tissue. The characteristics of neurodegeneration are well-described in animal models but have more recently been confirmed in the clinical setting, mostly by using non-invasive imaging approaches such as spectral domain optical coherence tomography (SD-OCT). The most frequent observations report loss of tissue in the nerve fiber layer and inner plexiform layer, confirming earlier findings from animal models. In several cases the reduction in inner retinal layers is reported in patients with little evidence of vascular lesions or macular edema, suggesting that degenerative loss of neural tissue in the inner retina can occur after relatively short durations of diabetes. Animal studies also suggest that neurodegeneration leading to retinal thinning is not limited to cell death and tissue loss but also includes changes in neuronal morphology, reduced synaptic protein expression and alterations in neurotransmission, including changes in expression of neurotransmitter receptors as well as neurotransmitter release, reuptake and metabolism. The concept of neurodegeneration as an early component of DR introduces the possibility to explore alternative therapies to prevent the onset of vision loss, including neuroprotective therapies and drugs targeting individual neurotransmitter systems, as well as more general neuroprotective approaches to preserve the integrity of the neural retina. In this review we consider some of the evidence for progressive retinal neurodegeneration in diabetes, and explore potential neuroprotective therapies.
Collapse
|
15
|
Welters A, Klüppel C, Mrugala J, Wörmeyer L, Meissner T, Mayatepek E, Heiss C, Eberhard D, Lammert E. NMDAR antagonists for the treatment of diabetes mellitus-Current status and future directions. Diabetes Obes Metab 2017; 19 Suppl 1:95-106. [PMID: 28880473 DOI: 10.1111/dom.13017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/18/2017] [Accepted: 05/20/2017] [Indexed: 12/16/2022]
Abstract
Diabetes mellitus is characterized by chronically elevated blood glucose levels accelerated by a progressive decline of insulin-producing β-cells in the pancreatic islets. Although medications are available to transiently adjust blood glucose to normal levels, the effects of current drugs are limited when it comes to preservation of a critical mass of functional β-cells to sustainably maintain normoglycemia. In this review, we recapitulate recent evidence on the role of pancreatic N-methyl-D-aspartate receptors (NMDARs) in β-cell physiology, and summarize effects of morphinan-based NMDAR antagonists that are beneficial for insulin secretion, glucose tolerance and islet cell survival. We further discuss NMDAR-mediated molecular pathways relevant for neuronal cell survival, which may also be important for the preservation of β-cell function and mass. Finally, we summarize the literature for evidence on the role of NMDARs in the development of diabetic long-term complications, and highlight beneficial pharmacologic aspects of NMDAR antagonists in diabetic nephropathy, retinopathy as well as neuropathy.
Collapse
Affiliation(s)
- Alena Welters
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Carina Klüppel
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Jessica Mrugala
- Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, Helmholtz Zentrum München, Neuherberg, Düsseldorf, Germany
| | - Laura Wörmeyer
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Thomas Meissner
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Ertan Mayatepek
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Christian Heiss
- Division of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Eckhard Lammert
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, Helmholtz Zentrum München, Neuherberg, Düsseldorf, Germany
| |
Collapse
|
16
|
Anaparti V, Pascoe CD, Jha A, Mahood TH, Ilarraza R, Unruh H, Moqbel R, Halayko AJ. Tumor necrosis factor regulates NMDA receptor-mediated airway smooth muscle contractile function and airway responsiveness. Am J Physiol Lung Cell Mol Physiol 2016; 311:L467-80. [PMID: 27371735 DOI: 10.1152/ajplung.00382.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 06/30/2016] [Indexed: 12/25/2022] Open
Abstract
We have shown that N-methyl-d-aspartate receptors (NMDA-Rs) are receptor-operated calcium entry channels in human airway smooth muscle (HASM) during contraction. Tumor necrosis factor (TNF) augments smooth muscle contractility by influencing pathways that regulate intracellular calcium flux and can alter NMDA-R expression and activity in cortical neurons and glial cells. We hypothesized that NMDA-R-mediated Ca(2+) and contractile responses of ASM can be altered by inflammatory mediators, including TNF. In cultured HASM cells, we assessed TNF (10 ng/ml, 48 h) effect on NMDA-R subunit abundance by quantitative PCR, confocal imaging, and immunoblotting. We observed dose- and time-dependent changes in NMDA-R composition: increased obligatory NR1 subunit expression and altered regulatory NR2 and inhibitory NR3 subunits. Measuring intracellular Ca(2+) flux in Fura-2-loaded HASM cultures, we observed that TNF exposure enhanced cytosolic Ca(2+) mobilization and changed the temporal pattern of Ca(2+) flux in individual myocytes induced by NMDA, an NMDA-R selective analog of glutamate. We measured airway responses to NMDA in murine thin-cut lung slices (TCLS) from allergen-naive animals and observed significant airway contraction. However, NMDA acted as a bronchodilator in TCLS from house dust mice-challenged mice and in allergen-naive TCLS subjected to TNF exposure. All contractile or bronchodilator responses were blocked by a selective NMDA-R antagonist, (2R)-amino-5-phosphonopentanoate, and bronchodilator responses were prevented by N(G)-nitro-l-arginine methyl ester (nitric oxide synthase inhibitor) or indomethacin (cyclooxygenase inhibitor). Collectively, we show that TNF augments NMDA-R-mediated Ca(2+) mobilization in HASM cells, whereas in multicellular TCLSs allergic inflammation and TNF exposure leads to NMDA-R-mediated bronchodilation. These findings reveal the unique contribution of ionotrophic NMDA-R to airway hyperreactivity.
Collapse
Affiliation(s)
- Vidyanand Anaparti
- Department of Immunology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada; Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; and
| | - Christopher D Pascoe
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Aruni Jha
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Thomas H Mahood
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Ramses Ilarraza
- Department of Immunology, University of Manitoba, Winnipeg, Canada
| | - Helmut Unruh
- Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; and Section of Thoracic Surgery, University of Manitoba, Winnipeg, Canada
| | - Redwan Moqbel
- Department of Immunology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Andrew J Halayko
- Department of Immunology, University of Manitoba, Winnipeg, Canada; Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada; Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; and
| |
Collapse
|
17
|
Vindeirinho J, Santiago AR, Cavadas C, Ambrósio AF, Santos PF. The Adenosinergic System in Diabetic Retinopathy. J Diabetes Res 2016; 2016:4270301. [PMID: 27034960 PMCID: PMC4789509 DOI: 10.1155/2016/4270301] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/29/2015] [Indexed: 11/18/2022] Open
Abstract
The neurodegenerative and inflammatory environment that is prevalent in the diabetic eye is a key player in the development and progression of diabetic retinopathy. The adenosinergic system is widely regarded as a significant modulator of neurotransmission and the inflammatory response, through the actions of the four types of adenosine receptors (A1R, A2AR, A2BR, and A3R), and thus could be revealed as a potential player in the events unfolding in the early stages of diabetic retinopathy. Herein, we review the studies that explore the impact of diabetic conditions on the retinal adenosinergic system, as well as the role of the said system in ameliorating or exacerbating those conditions. The experimental results described suggest that this system is heavily affected by diabetic conditions and that the modulation of its components could reveal potential therapeutic targets for the treatment of diabetic retinopathy, particularly in the early stages of the disease.
Collapse
Affiliation(s)
- J. Vindeirinho
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research (III), University of Coimbra, 3030-789 Coimbra, Portugal
- CNC.IBILI, University of Coimbra, 3004-504 Coimbra, Portugal
- *J. Vindeirinho:
| | - A. R. Santiago
- CNC.IBILI, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
| | - C. Cavadas
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-504 Coimbra, Portugal
- CNC.IBILI, University of Coimbra, 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - A. F. Ambrósio
- CNC.IBILI, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
| | - P. F. Santos
- CNC.IBILI, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3000-456 Coimbra, Portugal
| |
Collapse
|
18
|
Hernández C, Dal Monte M, Simó R, Casini G. Neuroprotection as a Therapeutic Target for Diabetic Retinopathy. J Diabetes Res 2016; 2016:9508541. [PMID: 27123463 PMCID: PMC4830713 DOI: 10.1155/2016/9508541] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/29/2016] [Accepted: 03/16/2016] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy (DR) is a multifactorial progressive disease of the retina and a leading cause of vision loss. DR has long been regarded as a vascular disorder, although neuronal death and visual impairment appear before vascular lesions, suggesting an important role played by neurodegeneration in DR and the appropriateness of neuroprotective strategies. Upregulation of vascular endothelial growth factor (VEGF), the main target of current therapies, is likely to be one of the first responses to retinal hyperglycemic stress and VEGF may represent an important survival factor in early phases of DR. Of central importance for clinical trials is the detection of retinal neurodegeneration in the clinical setting, and spectral domain optical coherence tomography seems the most indicated technique. Many substances have been tested in animal studies for their neuroprotective properties and for possible use in humans. Perhaps, the most intriguing perspective is the use of endogenous neuroprotective substances or nutraceuticals. Together, the data point to the central role of neurodegeneration in the pathogenesis of DR and indicate neuroprotection as an effective strategy for treating this disease. However, clinical trials to determine not only the effectiveness and safety but also the compliance of a noninvasive route of drug administration are needed.
Collapse
Affiliation(s)
- Cristina Hernández
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabolicas Asociadas) and Diabetes and Metabolism Research Unit, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autonoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
- *Cristina Hernández: and
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Rafael Simó
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabolicas Asociadas) and Diabetes and Metabolism Research Unit, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autonoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
| | - Giovanni Casini
- Department of Biology, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
- *Giovanni Casini:
| |
Collapse
|
19
|
Castilho Á, Madsen E, Ambrósio AF, Veruki ML, Hartveit E. Diabetic hyperglycemia reduces Ca2+ permeability of extrasynaptic AMPA receptors in AII amacrine cells. J Neurophysiol 2015; 114:1545-53. [PMID: 26156384 DOI: 10.1152/jn.00295.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 07/01/2015] [Indexed: 11/22/2022] Open
Abstract
There is increasing evidence that diabetic retinopathy is a primary neuropathological disorder that precedes the microvascular pathology associated with later stages of the disease. Recently, we found evidence for altered functional properties of synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in A17, but not AII, amacrine cells in the mammalian retina, and the observed changes were consistent with an upregulation of the GluA2 subunit, a key determinant of functional properties of AMPA receptors, including Ca(2+) permeability and current-voltage (I-V) rectification properties. Here, we have investigated functional changes of extrasynaptic AMPA receptors in AII amacrine cells evoked by diabetes. With patch-clamp recording of nucleated patches from retinal slices, we measured Ca(2+) permeability and I-V rectification in rats with ∼3 wk of streptozotocin-induced diabetes and age-matched, noninjected controls. Under bi-ionic conditions (extracellular Ca(2+) concentration = 30 mM, intracellular Cs(+) concentration = 171 mM), the reversal potential (Erev) of AMPA-evoked currents indicated a significant reduction of Ca(2+) permeability in diabetic animals [Erev = -17.7 mV, relative permeability of Ca(2+) compared with Cs(+) (PCa/PCs) = 1.39] compared with normal animals (Erev = -7.7 mV, PCa/PCs = 2.35). Insulin treatment prevented the reduction of Ca(2+) permeability. I-V rectification was examined by calculating a rectification index (RI) as the ratio of the AMPA-evoked conductance at +40 and -60 mV. The degree of inward rectification in patches from diabetic animals (RI = 0.48) was significantly reduced compared with that in normal animals (RI = 0.30). These results suggest that diabetes evokes a change in the functional properties of extrasynaptic AMPA receptors of AII amacrine cells. These changes could be representative for extrasynaptic AMPA receptors elsewhere in AII amacrine cells and suggest that synaptic and extrasynaptic AMPA receptors are differentially regulated.
Collapse
Affiliation(s)
- Áurea Castilho
- Department of Biomedicine, University of Bergen, Bergen, Norway; Institute of Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Eirik Madsen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - António F Ambrósio
- Institute of Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center for Neuroscience and Cell Biology, Institute of Biomedical Imaging and Life Sciences (CNC.IBILI) Consortium, University of Coimbra, Coimbra, Portugal; and Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | | | - Espen Hartveit
- Department of Biomedicine, University of Bergen, Bergen, Norway;
| |
Collapse
|
20
|
Disruption of a neural microcircuit in the rod pathway of the mammalian retina by diabetes mellitus. J Neurosci 2015; 35:5422-33. [PMID: 25834065 DOI: 10.1523/jneurosci.5285-14.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Diabetes leads to dysfunction of the neural retina before and independent of classical microvascular diabetic retinopathy, but previous studies have failed to demonstrate which neurons and circuits are affected at the earliest stages. Here, using patch-clamp recording and two-photon Ca(2+) imaging in rat retinal slices, we investigated diabetes-evoked changes in a microcircuit consisting of rod bipolar cells and their dyad postsynaptic targets, AII and A17 amacrine cells, which play an essential role in processing scotopic visual signals. AII amacrines forward their signals to ON- and OFF-cone bipolar cells and A17 amacrines provide GABAergic feedback inhibition to rod bipolar cells. Whereas Ca(2+)-permeable AMPA receptors mediate input from rod bipolar cells to both AII and A17 amacrines, diabetes changes the synaptic receptors on A17, but not AII amacrine cells. This was expressed as a change in pharmacological properties and single-channel conductance of the synaptic receptors, consistent with an upregulation of the AMPA receptor GluA2 subunit and reduced Ca(2+) permeability. In addition, two-photon imaging revealed reduced agonist-evoked influx of Ca(2+) in dendritic varicosities of A17 amacrine cells from diabetic compared with normal animals. Because Ca(2+)-permeable receptors in A17 amacrine cells mediate synaptic release of GABA, the reduced Ca(2+) permeability of these receptors in diabetic animals leads to reduced release of GABA, followed by disinhibition and increased release of glutamate from rod bipolar cells. This perturbation of neuron and microcircuit dynamics can explain the decreased dynamic range and sensitivity of scotopic vision that has been observed in diabetes.
Collapse
|
21
|
Primary retinal cultures as a tool for modeling diabetic retinopathy: an overview. BIOMED RESEARCH INTERNATIONAL 2015; 2015:364924. [PMID: 25688355 PMCID: PMC4320900 DOI: 10.1155/2015/364924] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/04/2014] [Accepted: 12/23/2014] [Indexed: 12/21/2022]
Abstract
Experimental models of diabetic retinopathy (DR) have had a crucial role in the comprehension of the pathophysiology of the disease and the identification of new therapeutic strategies. Most of these studies have been conducted in vivo, in animal models. However, a significant contribution has also been provided by studies on retinal cultures, especially regarding the effects of the potentially toxic components of the diabetic milieu on retinal cell homeostasis, the characterization of the mechanisms on the basis of retinal damage, and the identification of potentially protective molecules. In this review, we highlight the contribution given by primary retinal cultures to the study of DR, focusing on early neuroglial impairment. We also speculate on possible themes into which studies based on retinal cell cultures could provide deeper insight.
Collapse
|
22
|
Jiang H, Du J, He T, Qu J, Song Z, Wu S. Increased D-serine in the aqueous and vitreous humour in patients with proliferative diabetic retinopathy. Clin Exp Ophthalmol 2014; 42:841-5. [PMID: 24645972 DOI: 10.1111/ceo.12329] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 03/12/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Haiyan Jiang
- School of Optometry and Ophthalmology and Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Jinlin Du
- School of Optometry and Ophthalmology and Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Tao He
- School of Optometry and Ophthalmology and Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Jia Qu
- School of Optometry and Ophthalmology and Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Zongming Song
- School of Optometry and Ophthalmology and Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Shengzhou Wu
- School of Optometry and Ophthalmology and Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| |
Collapse
|
23
|
Neuropeptide Y receptors activation protects rat retinal neural cells against necrotic and apoptotic cell death induced by glutamate. Cell Death Dis 2013; 4:e636. [PMID: 23681231 PMCID: PMC3674367 DOI: 10.1038/cddis.2013.160] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
It has been claimed that glutamate excitotoxicity might have a role in the pathogenesis of several retinal degenerative diseases, including glaucoma and diabetic retinopathy. Neuropeptide Y (NPY) has neuroprotective properties against excitotoxicity in the hippocampus, through the activation of Y1, Y2 and/or Y5 receptors. The principal objective of this study is to investigate the potential protective role of NPY against glutamate-induced toxicity in rat retinal cells (in vitro and in an animal model), unraveling the NPY receptors and intracellular mechanisms involved. Rat retinal neural cell cultures were prepared from newborn Wistar rats (P3-P5) and exposed to glutamate (500 μM) for 24 h. Necrotic cell death was evaluated by propidium iodide (PI) assay and apoptotic cell death using TUNEL and caspase-3 assays. The cell types present in culture were identified by immunocytochemistry. The involvement of NPY receptors was assessed using selective agonists and antagonists. Pre-treatment of cells with NPY (100 nM) inhibited both necrotic cell death (PI-positive cells) and apoptotic cell death (TUNEL-positive cells and caspase 3-positive cells) triggered by glutamate, with the neurons being the cells most strongly affected. The activation of NPY Y2, Y4 and Y5 receptors inhibited necrotic cell death, while apoptotic cell death was only prevented by the activation of NPY Y5 receptor. Moreover, NPY neuroprotective effect was mediated by the activation of PKA and p38K. In the animal model, NPY (2.35 nmol) was intravitreally injected 2 h before glutamate (500 nmol) injection into the vitreous. The protective role of NPY was assessed 24 h after glutamate (or saline) injection by TUNEL assay and Brn3a (marker of ganglion cells) immunohistochemistry. NPY inhibited the increase in the number of TUNEL-positive cells and the decrease in the number of Brn3a-positive cells induced by glutamate. In conclusion, NPY and NPY receptors can be considered potential targets to treat retinal degenerative diseases, such as glaucoma and diabetic retinopathy.
Collapse
|
24
|
Vila A, Satoh H, Rangel C, Mills SL, Hoshi H, O'Brien J, Marshak DR, Macleish PR, Marshak DW. Histamine receptors of cones and horizontal cells in Old World monkey retinas. J Comp Neurol 2012; 520:528-43. [PMID: 21800315 DOI: 10.1002/cne.22731] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In primates the retina receives input from histaminergic neurons in the posterior hypothalamus that are active during the day. In order to understand how this input contributes to information processing in Old World monkey retinas, we have been localizing histamine receptors (HR) and studying the effects of histamine on the neurons that express them. Previously, we localized HR3 to the tips of ON bipolar cell dendrites and showed that histamine hyperpolarizes the cells via this receptor. We raised antisera against synthetic peptides corresponding to an extracellular domain of HR1 between the 4th and 5th transmembrane domains and to an intracellular domain near the carboxyl terminus of HR2. Using these, we localized HR1 to horizontal cells and a small number of amacrine cells and localized HR2 to puncta closely associated with synaptic ribbons inside cone pedicles. Consistent with this, HR1 mRNA was detected in horizontal cell perikarya and primary dendrites and HR2 mRNA was found in cone inner segments. We studied the effect of 5 μM exogenous histamine on primate cones in macaque retinal slices. Histamine reduced I(h) at moderately hyperpolarized potentials, but not the maximal current. This would be expected to increase the operating range of cones and conserve ATP in bright, ambient light. Thus, all three major targets of histamine are in the outer plexiform layer, but the retinopetal axons containing histamine terminate in the inner plexiform layer. Taken together, the findings in these three studies suggest that histamine acts primarily via volume transmission in primate retina.
Collapse
Affiliation(s)
- Alejandro Vila
- Department of Neurobiology and Anatomy, Medical School, University of Texas at Health Science Center at Houston, Houston, Texas, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Castilho AF, Liberal JT, Baptista FI, Gaspar JM, Carvalho AL, Ambrósio AF. Elevated glucose concentration changes the content and cellular localization of AMPA receptors in the retina but not in the hippocampus. Neuroscience 2012; 219:23-32. [PMID: 22659015 DOI: 10.1016/j.neuroscience.2012.05.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/22/2012] [Accepted: 05/22/2012] [Indexed: 10/28/2022]
Abstract
Diabetic retinopathy and diabetic encephalopathy are two common complications of diabetes mellitus. The impairment of glutamatergic neurotransmission in the retina and hippocampus has been suggested to be involved in the pathogenesis of these diabetic complications. In this study, we investigated the effect of elevated glucose concentration and diabetes on the protein content and surface expression of AMPA receptor subunits in the rat retina and hippocampus. We have used two models, cultured retinal and hippocampal cells exposed to elevated glucose concentration and an animal model of streptozotocin-induced type 1 diabetes. The immunoreactivity of GluA1, GluA2 and GluA4 was evaluated by Western blot and immunocytochemistry. The levels of these subunits at the plasma membrane were evaluated by biotinylation and purification of plasma membrane-associated proteins. Elevated glucose concentration increased the total levels of GluA2 subunit of AMPA receptors in retinal neural cells, but not of the subunits GluA1 or GluA4. However, at the plasma membrane, elevated glucose concentration induced an increase of all AMPA receptor subunits. In cultured hippocampal neurons, elevated glucose concentration did not induce significant alterations in the levels of AMPA receptor subunits. In the retinas of diabetic rats there were no persistent changes in the levels of AMPA receptor subunits comparing to aged-matched control retinas. Also, no consistent changes were detected in the levels of GluA1, GluA2 or GluA4 in the hippocampus of diabetic rats. We demonstrate that elevated glucose concentration induces early changes in AMPA receptor subunits, mainly in GluA2 subunit, in retinal neural cells. Conversely, hippocampal neurons seem to remain unaffected by elevated glucose concentration, concerning the expression of AMPA receptors, suggesting that AMPA receptors are more susceptible to the stress caused by elevated glucose concentration in retinal cells than in hippocampal neurons.
Collapse
Affiliation(s)
- A F Castilho
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | | | | | | | | | | |
Collapse
|
26
|
Lin Y, Jones BW, Liu A, Vazquéz-Chona FR, Lauritzen JS, Ferrell WD, Marc RE. Rapid glutamate receptor 2 trafficking during retinal degeneration. Mol Neurodegener 2012; 7:7. [PMID: 22325330 PMCID: PMC3296582 DOI: 10.1186/1750-1326-7-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 02/10/2012] [Indexed: 01/03/2023] Open
Abstract
Background Retinal degenerations, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), are characterized by photoreceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic glutamate receptor (iGluR) reprogramming in retinal degenerations, we hypothesized that the edited glutamate receptor 2 (GluR2) subunit and its trafficking may be modulated in retinal degenerations. Results Adult albino Balb/C mice were exposed to intense light for 24 h to induce light-induced retinal degeneration (LIRD). We found that prior to the onset of photoreceptor loss, protein levels of GluR2 and related trafficking proteins, including glutamate receptor-interacting protein 1 (GRIP1) and postsynaptic density protein 95 (PSD-95), were rapidly increased. LIRD triggered neuritogenesis in photoreceptor survival regions, where GluR2 and its trafficking proteins were expressed in the anomalous dendrites. Immunoprecipitation analysis showed interaction between KIF3A and GRIP1 as well as PSD-95, suggesting that KIF3A may mediate transport of GluR2 and its trafficking proteins to the novel dendrites. However, in areas of photoreceptor loss, GluR2 along with its trafficking proteins nearly vanished in retracted retinal neurites. Conclusions All together, LIRD rapidly triggers GluR2 plasticity, which is a potential mechanism behind functionally phenotypic revisions of retinal neurons and neuritogenesis during retinal degenerations.
Collapse
Affiliation(s)
- Yanhua Lin
- Department of Ophthalmology, John A, Moran Eye Center, University of Utah School of Medicine, 65 Mario Capecchi Drive, Salt Lake City, UT 84132, USA
| | | | | | | | | | | | | |
Collapse
|
27
|
Barber AJ, Gardner TW, Abcouwer SF. The significance of vascular and neural apoptosis to the pathology of diabetic retinopathy. Invest Ophthalmol Vis Sci 2011; 52:1156-63. [PMID: 21357409 DOI: 10.1167/iovs.10-6293] [Citation(s) in RCA: 291] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The most striking features of diabetic retinopathy are the vascular abnormalities that are apparent by fundus examination. There is also strong evidence that diabetes causes apoptosis of neural and vascular cells in the retina. Thus, there is good reason to define diabetic retinopathy as a form of chronic neurovascular degeneration. In keeping with the gradual onset of retinopathy in humans, the rate of cell loss in the animal models is insidious, even in uncontrolled diabetes. This is not surprising given that a sustained high rate of cell loss without regeneration would soon lead to catastrophic tissue destruction. The consequences of ongoing cell death are difficult to detect, and even the quantification of cumulative cell loss requires painstaking histology and microscopy. This subtle cell loss raises the issue of the relevance of the phenomenon to the progression of diabetic retinopathy and the ultimate loss of vision. Neuronal function may be compromised in advance of apoptosis, contributing to an early deterioration of vision. Here we review some of the evidence supporting apoptotic cell death as a contributing mechanism of diabetic retinopathy, explore some of the potential causes, and discuss the potential links between apoptosis and loss of visual function in diabetic retinopathy.
Collapse
Affiliation(s)
- Alistair J Barber
- Department of Ophthalmology, Penn State Hershey Eye Center, Penn State Hershey College of Medicine, Hershey, Pennsylvania 17033, USA.
| | | | | |
Collapse
|
28
|
Expression and high glucose-mediated regulation of K+ channel interacting protein 3 (KChIP3) and KV4 channels in retinal Müller glial cells. Biochem Biophys Res Commun 2010; 404:678-83. [PMID: 21147063 DOI: 10.1016/j.bbrc.2010.12.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Accepted: 12/07/2010] [Indexed: 11/23/2022]
Abstract
Normal vision depends on the correct function of retinal neurons and glia and it is impaired in the course of diabetic retinopathy. Müller cells, the main glial cells of the retina, suffer morphological and functional alterations during diabetes participating in the pathological retinal dysfunction. Recently, we showed that Müller cells express the pleiotropic protein potassium channel interacting protein 3 (KChIP3), an integral component of the voltage-gated K(+) channels K(V)4. Here, we sought to analyze the role of KChIP3 in the molecular mechanisms underlying hyperglycemia-induced phenotypic changes in the glial elements of the retina. The expression and function of KChIp3 was analyzed in vitro in rat Müller primary cultures grown under control (5.6 mM) or high glucose (25 mM) (diabetic-like) conditions. We show the up-regulation of KChIP3 expression in Müller cell cultures under high glucose conditions and demonstrate a previously unknown interaction between the K(V)4 channel and KChIP3 in Müller cells. We show evidence for the expression of a 4-AP-sensitive transient outward voltage-gated K(+) current and an alteration in the inactivation of the macroscopic outward K(+) currents expressed in high glucose-cultured Müller cells. Our data support the notion that induction of KChIP3 and functional changes of K(V)4 channels in Müller cells could exert a physiological role in the onset of diabetic retinopathy.
Collapse
|
29
|
Thaler S, Fiedorowicz M, Choragiewicz TJ, Bolz S, Tura A, Henke-Fahle S, Yoeruek E, Zrenner E, Bartz-Schmidt KU, Ziemssen F, Schuettauf F. Toxicity testing of the VEGF inhibitors bevacizumab, ranibizumab and pegaptanib in rats both with and without prior retinal ganglion cell damage. Acta Ophthalmol 2010; 88:e170-6. [PMID: 20491691 DOI: 10.1111/j.1755-3768.2010.01927.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To evaluate the effects of intravitreally introduced vascular endothelial growth factor (VEGF) inhibitors in rat eyes with healthy retinal ganglion cells (RGC) and into others with N-methyl-D-aspartate (NMDA)-induced RGC damage. METHODS Bevacizumab, ranibizumab and pegaptanib were intravitreally injected each at two different concentrations. Respective vehicles of the three substances served as controls. In a different group, additionally a rat anti-VEGF antibody was injected after NMDA treatment. Retrogradely labelled RGC were counted on retinal wholemounts 1 week or 2 months after intravitreal introduction of the VEGF inhibitors. Electron microscopy (EM) was performed on normal rat eyes 2 months after introduction of the VEGF inhibitors. RESULTS RGC counts in healthy rat eyes were essentially unchanged from those of the control animals after the administration of both low and high concentrations of bevacizumab, ranibizumab or pegaptanib. Compared to the other two substances, however, high doses of pegaptanib and its respective vehicle significantly decreased RGC after 1 week and led to a marked increase of mitochondrial swelling in EM. In eyes with NMDA-induced RGC damage, no changes of RGC numbers were detected after rat anti-VEGF antibody or bevacizumab, ranibizumab and pegaptanib at both tested concentrations. CONCLUSIONS Even at higher doses, bevacizumab and ranibizumab showed no toxic effects on RGC in vivo in either untreated rats or in the NMDA-induced RGC damage model. Also a rat anti-VEGF antibody showed no adverse effects after NMDA. Anti-VEGF therapy therefore appears safe even for eyes with additional excitotoxic RGC damage. Potential harm from the pegaptanib carrier solution at very high local concentrations cannot be excluded.
Collapse
Affiliation(s)
- Sebastian Thaler
- Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Semkova I, Huemmeke M, Ho MS, Merkl B, Abari E, Paulsson M, Joussen AM, Plomann M. Retinal localization of the glutamate receptor GluR2 and GluR2-regulating proteins in diabetic rats. Exp Eye Res 2010; 90:244-53. [DOI: 10.1016/j.exer.2009.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 09/17/2009] [Accepted: 10/20/2009] [Indexed: 11/29/2022]
|
31
|
Park SE, Sun HJ, Lee HJ, Park TK, Ohn YH. The Role of Electroretinography in Assessing the Progression of Diabetic Retinopathy. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2010. [DOI: 10.3341/jkos.2010.51.5.693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Su Eun Park
- Department of Ophthalmology, Hallym University College of Medicine, Seoul, Korea
| | - Hae Jung Sun
- Department of Ophthalmology, Soonchunhyang University College of Medicine, Bucheon, Korea
| | - Hyun Joon Lee
- Department of Ophthalmology, Soonchunhyang University College of Medicine, Bucheon, Korea
| | - Tae Kwann Park
- Department of Ophthalmology, Soonchunhyang University College of Medicine, Bucheon, Korea
| | - Young-Hoon Ohn
- Department of Ophthalmology, Soonchunhyang University College of Medicine, Bucheon, Korea
| |
Collapse
|
32
|
VanGuilder HD, Brucklacher RM, Patel K, Ellis RW, Freeman WM, Barber AJ. Diabetes downregulates presynaptic proteins and reduces basal synapsin I phosphorylation in rat retina. Eur J Neurosci 2008; 28:1-11. [DOI: 10.1111/j.1460-9568.2008.06322.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|