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Pichi F, Neri P, Aljeneibi S, Hay S, Chaudhry H, Saturno MC, Carreno E. In Vivo Visualization of Macrophage-Like Cells in Patients with Uveitis by Use of En Face Swept Source Optical Coherence Tomography. Ocul Immunol Inflamm 2024; 32:1532-1538. [PMID: 37722841 DOI: 10.1080/09273948.2023.2254369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 09/20/2023]
Abstract
AIMS To detect macrophage-like cells (MLCs) in uveitis patients and describe their characteristics compared to healthy subjects by using en face SS-OCTA. METHODS Fifteen consecutive patients with "active" uveitis and 11 healthy participants underwent 6 macular scans of 6×6mm using SS-OCTA. The 3μm en face OCT slabs on inner limiting membrane were used to visualize the MLCs. RESULTS In healthy subjects there was an average of 478.2±149.7 MLCs with a density of 13.28±4.16 cells/mm2. MLCs were larger in patients with "active" uveitis than in controls (891.18±69.46 µm2 vs.885±77.53 µm2). Patients with "active" anterior uveitis had a significantly reduced count and density of MLCs (172±14.68 and 4.77±0.4 cell/mm2) compared to controls, while patients with posterior uveitis had a statistically increased count (546.1±132.4) and area (909.23+/-54.97 µm2) of MLCs compared to controls. CONCLUSIONS MLCs detected with en face SS-OCTA are increased in number and size in active posterior uveitis eyes compared to controls.
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Affiliation(s)
- Francesco Pichi
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Piergiorgio Neri
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Shaikha Aljeneibi
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Steven Hay
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Hannah Chaudhry
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | | | - Ester Carreno
- Department of Ophthalmology, University Hospital Fundación Jiménez Díaz, Madrid, Spain
- Department of Ophthalmology, University Hospital Rey Juan Carlos, Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, Spain
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Dimethyl Fumarate Promotes the Survival of Retinal Ganglion Cells after Optic Nerve Injury, Possibly through the Nrf2/HO-1 Pathway. Int J Mol Sci 2020; 22:ijms22010297. [PMID: 33396673 PMCID: PMC7795407 DOI: 10.3390/ijms22010297] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/18/2020] [Accepted: 12/28/2020] [Indexed: 12/18/2022] Open
Abstract
This study aimed to verify whether dimethyl fumarate (DMF) promotes the survival of retinal ganglion cells (RGCs) after optic nerve crush (ONC) accompanied by activation of the NF-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. We examined changes in the densities of tubulin β3 (TUBB3)-positive RGCs and the amplitudes of the positive scotopic threshold response (pSTR), reflecting the functional activity of RGCs, recorded on an electroretinogram, with daily administration of DMF, on day 7 after ONC. Furthermore, immunohistochemical and immunoblotting analyses were performed to study the activation of the Nrf2/HO-1 pathway using retinas treated with daily administration of DMF. Daily administration of DMF increasedthe density of TUBB3-positive RGCs in a dose-dependent fashion and significantly increased the amplitude of the pSTR. Immunohistochemical analysis showed that DMF administration increased the immunoreactivity for Nrf2 and HO-1, a potent antioxidant enzyme, in RGCs immunolabeled with RNA-binding protein with multiple splicing (RBPMS). Immunoblotting analysis revealed an increase in the nuclear expression of Nrf2 and marked upregulation of HO-1 after DMF administration. These results suggest that DMF has survival-promoting effects in RGC after ONC, possibly via the Nrf2/HO-1 pathway.
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Kokona D, Häner NU, Ebneter A, Zinkernagel MS. Imaging of macrophage dynamics with optical coherence tomography in anterior ischemic optic neuropathy. Exp Eye Res 2016; 154:159-167. [PMID: 27914988 DOI: 10.1016/j.exer.2016.11.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 11/19/2016] [Accepted: 11/27/2016] [Indexed: 12/13/2022]
Abstract
Anterior ischemic optic neuropathy (AION) is a relatively common cause of visual loss and results from hypoperfusion of the small arteries of the anterior portion of the optic nerve. AION is the leading cause of sudden optic nerve related vision loss with approximately 10 cases per 100'000 in the population over 50 years. To date there is no established treatment for AION and therefore a better understanding of the events occurring at the level of the optic nerve head (ONH) would be important to design future therapeutic strategies. The optical properties of the eye allow imaging of the optic nerve in vivo, which is a part of the CNS, during ischemia. Experimentally laser induced optic neuropathy (eLiON) displays similar anatomical features as anterior ischemic optic neuropathy in humans. After laser induced optic neuropathy we show that hyperreflective dots in optical coherence tomography correspond to mononuclear cells in histology. Using fluorescence-activated flow cytometry (FACS) we found these cells to peak one week after eLiON. These observations were translated to OCT findings in patients with AION, where similar dynamics of hyperreflective dots at the ONH were identified. Our data suggests that activated macrophages can be identified as hyperreflective dots in OCT.
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Affiliation(s)
- Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Nathanael U Häner
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Andreas Ebneter
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland; Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland; Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland.
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Russo R, Varano GP, Adornetto A, Nucci C, Corasaniti MT, Bagetta G, Morrone LA. Retinal ganglion cell death in glaucoma: Exploring the role of neuroinflammation. Eur J Pharmacol 2016; 787:134-42. [PMID: 27044433 DOI: 10.1016/j.ejphar.2016.03.064] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 03/10/2016] [Accepted: 03/31/2016] [Indexed: 01/06/2023]
Abstract
In clinical glaucoma, as well as in experimental models, the loss of retinal ganglion cells occurs by apoptosis. This final event is preceded by inflammatory responses involving the activation of innate and adaptive immunity, with retinal and optic nerve resident glial cells acting as major players. Here we review the current literature on the role of neuroinflammation in neurodegeneration, focusing on the inflammatory molecular mechanisms involved in the pathogenesis and progression of the optic neuropathy.
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Affiliation(s)
- Rossella Russo
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Arcavacata di Rende, Italy.
| | - Giuseppe Pasquale Varano
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Annagrazia Adornetto
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Carlo Nucci
- Ophthalmology Unit, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome Italy
| | | | - Giacinto Bagetta
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Arcavacata di Rende, Italy; University Center for Adaptive Disorders and Head Pain, Section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, Arcavacata di Rende, Italy
| | - Luigi Antonio Morrone
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Arcavacata di Rende, Italy; University Center for Adaptive Disorders and Head Pain, Section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, Arcavacata di Rende, Italy
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Silverman SM, Kim BJ, Howell GR, Miller J, John SWM, Wordinger RJ, Clark AF. C1q propagates microglial activation and neurodegeneration in the visual axis following retinal ischemia/reperfusion injury. Mol Neurodegener 2016; 11:24. [PMID: 27008854 PMCID: PMC4806521 DOI: 10.1186/s13024-016-0089-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/18/2016] [Indexed: 12/03/2022] Open
Abstract
Background C1q represents the initiating protein of the classical complement cascade, however recent findings indicate pathway independent roles such as developmental pruning of retinal ganglion cell (RGC) axons. Furthermore, chronic neuroinflammation, including increased expression of C1q and activation of microglia and astrocytes, appears to be a common finding among many neurodegenerative disease models. Here we compare the effects of a retinal ischemia/reperfusion (I/R) injury on glial activation and neurodegeneration in wild type (WT) and C1qa-deficient mice in the retina and superior colliculus (SC). Retinal I/R was induced in mice through elevation of intraocular pressure to 120 mmHg for 60 min followed by reperfusion. Glial cell activation and population changes were assessed using immunofluorescence. Neuroprotection was determined using histological measurements of retinal layer thickness, RGC counts, and visual function by flash electroretinography (ERG). Results Retinal I/R injury significantly upregulated C1q expression in the retina as early as 72 h and within 7 days in the superficial SC, and was sustained as long as 28 days. Accompanying increased C1q expression was activation of microglia and astrocytes as well as a significantly increased glial population density observed in the retina and SC. Microglial activation and changes in density were completely ablated in C1qa-deficient mice, interestingly however there was no effect on astrocytes. Furthermore, loss of C1qa significantly rescued I/R-induced loss of RGCs and protected against retinal layer thinning in comparison to WT mice. ERG assessment revealed early preservation of b-wave amplitude deficits from retinal I/R injury due to C1qa-deficiency that was lost by day 28. Conclusions Our results for the first time demonstrate the spatiotemporal changes in the neuroinflammatory response following retinal I/R injury at both local and distal sites of injury. In addition, we have shown a role for C1q as a primary mediator of microglial activation and pathological damage. This suggests developmental mechanisms of C1q may be re-engaged during injury response, modulation of which may be beneficial for neuroprotection. Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0089-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sean M Silverman
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | - Byung-Jin Kim
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | | | | | - Simon W M John
- The Jackson Laboratory, Bar Harbor, 04609, ME, USA.,Howard Hughes Medical Institute, Bar Harbor, ME, 04609, USA
| | - Robert J Wordinger
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA.
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Microglial Activation Promotes Cell Survival in Organotypic Cultures of Postnatal Mouse Retinal Explants. PLoS One 2015; 10:e0135238. [PMID: 26252475 PMCID: PMC4529135 DOI: 10.1371/journal.pone.0135238] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 07/20/2015] [Indexed: 02/03/2023] Open
Abstract
The role of microglia during neurodegeneration remains controversial. We investigated whether microglial cells have a neurotoxic or neuroprotective function in the retina. Retinal explants from 10-day-old mice were treated in vitro with minocycline to inhibit microglial activation, with LPS to increase microglial activation, or with liposomes loaded with clodronate (Lip-Clo) to deplete microglial cells. Flow cytometry was used to assess the viability of retinal cells in the explants and the TUNEL method to show the distribution of dead cells. The immunophenotypic and morphological features of microglia and their distribution were analyzed with flow cytometry and immunocytochemistry. Treatment of retinal explants with minocycline reduced microglial activation and simultaneously significantly decreased cell viability and increased the presence of TUNEL-labeled cell profiles. This treatment also prevented the migration of microglial cells towards the outer nuclear layer, where cell death was most abundant. The LPS treatment increased microglial activation but had no effect on cell viability or microglial distribution. Finally, partial microglial removal with Lip-Clo diminished the cell viability in the retinal explants, showing a similar effect to that of minocycline. Hence, cell viability is diminished in retinal explants cultured in vitro when microglial cells are removed or their activation is inhibited, indicating a neurotrophic role for microglia in this system.
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Macrophages and Uveitis in Experimental Animal Models. Mediators Inflamm 2015; 2015:671417. [PMID: 26078494 PMCID: PMC4452861 DOI: 10.1155/2015/671417] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/14/2015] [Accepted: 03/31/2015] [Indexed: 11/17/2022] Open
Abstract
Resident and infiltrated macrophages play relevant roles in uveitis as effectors of innate immunity and inductors of acquired immunity. They are major effectors of tissue damage in uveitis and are also considered to be potent antigen-presenting cells. In the last few years, experimental animal models of uveitis have enabled us to enhance our understanding of the leading role of macrophages in eye inflammation processes, including macrophage polarization in experimental autoimmune uveoretinitis and the major role of Toll-like receptor 4 in endotoxin-induced uveitis. This improved knowledge should guide advantageous iterative research to establish mechanisms and possible therapeutic targets for human uveitis resolution.
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Choe TE, Abbott CJ, Piper C, Wang L, Fortune B. Comparison of longitudinal in vivo measurements of retinal nerve fiber layer thickness and retinal ganglion cell density after optic nerve transection in rat. PLoS One 2014; 9:e113011. [PMID: 25393294 PMCID: PMC4231142 DOI: 10.1371/journal.pone.0113011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 10/23/2014] [Indexed: 11/23/2022] Open
Abstract
Purpose To determine the relationship between longitudinal in vivo measurements of retinal nerve fiber layer thickness (RNFLT) and retinal ganglion cell (RGC) density after unilateral optic nerve transection (ONT). Methods Nineteen adult Brown-Norway rats were studied; N = 10 ONT plus RGC label, N = 3 ONT plus vehicle only (sans label), N = 6 sham ONT plus RGC label. RNFLT was measured by spectral domain optical coherence tomography (SD-OCT) at baseline then weekly for 1 month. RGCs were labeled by retrograde transport of fluorescently conjugated cholera toxin B (CTB) from the superior colliculus 48 hours prior to ONT or sham surgery. RGC density measurements were obtained by confocal scanning laser ophthalmoscopy (CSLO) at baseline and weekly for 1 month. RGC density and reactivity of microglia (anti-Iba1) and astrocytes (anti-GFAP) were determined from post mortem fluorescence microscopy of whole-mount retinae. Results RNFLT decreased after ONT by 17% (p<0.05), 30% (p<0.0001) and 36% (p<0.0001) at weeks 2, 3 and 4. RGC density decreased after ONT by 18%, 69%, 85% and 92% at weeks 1, 2, 3 and 4 (p<0.0001 each). RGC density measured in vivo at week 4 and post mortem by microscopy were strongly correlated (R = 0.91, p<0.0001). In vivo measures of RNFLT and RGC density were strongly correlated (R = 0.81, p<0.0001). In ONT- CTB labeled fellow eyes, RNFLT increased by 18%, 52% and 36% at weeks 2, 3 and 4 (p<0.0001), but did not change in fellow ONT-eyes sans CTB. Microgliosis was evident in the RNFL of the ONT-CTB fellow eyes, exceeding that observed in other fellow eyes. Conclusions In vivo measurements of RNFLT and RGC density are strongly correlated and can be used to monitor longitudinal changes after optic nerve injury. The strong fellow eye effect observed in eyes contralateral to ONT, only in the presence of CTB label, consisted of a dramatic increase in RNFLT associated with retinal microgliosis.
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Affiliation(s)
- Tiffany E. Choe
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Carla J. Abbott
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Chelsea Piper
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Lin Wang
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
- * E-mail:
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Varghese B, Vlashi E, Xia W, Ayala Lopez W, Paulos CM, Reddy J, Xu LC, Low PS. Folate receptor-β in activated macrophages: ligand binding and receptor recycling kinetics. Mol Pharm 2014; 11:3609-16. [PMID: 25166491 DOI: 10.1021/mp500348e] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Activated macrophages overexpress a receptor for the vitamin folic acid termed the folate receptor β (FR-β). Because conjugation of folate to low molecular weight drugs, genes, liposomes, nanoparticles, and imaging agents has minor effects on FR binding, the vitamin can be exploited to target both therapeutic and imaging agents to activated macrophages without promoting their uptake by other healthy cells. In this paper, we characterize the binding, internalization, and recycling kinetics of FR-β on activated macrophages in inflamed tissues of rats with adjuvant-induced arthritis. Our results demonstrate that saturation of macrophage FR is achieved at injection doses of ∼150-300 nmol/kg, with more rapidly perfused tissues saturating at lower doses than inflamed appendages. After binding, FR-β internalizes and recycles back to the cell surface every ∼10-20 min, providing empty receptors for additional folate conjugate uptake. Because the half-life of low molecular weight folate conjugates in the vasculature is usually <1 h, these data suggest that targeting of folate conjugates to activated macrophages in vivo can be maximized by frequent dosing at conjugate concentrations that barely saturate FR (∼150 nmol/kg), thereby minimizing nonspecific binding to receptor-negative tissues and maximizing the probability that unoccupied cell surface receptors will be exposed to folate-drug conjugate.
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Affiliation(s)
- Bindu Varghese
- Department of Chemistry, Purdue University , West Lafayette, Indiana 49707, United States
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10
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Rojas B, Gallego BI, Ramírez AI, Salazar JJ, de Hoz R, Valiente-Soriano FJ, Avilés-Trigueros M, Villegas-Perez MP, Vidal-Sanz M, Triviño A, Ramírez JM. Microglia in mouse retina contralateral to experimental glaucoma exhibit multiple signs of activation in all retinal layers. J Neuroinflammation 2014; 11:133. [PMID: 25064005 PMCID: PMC4128533 DOI: 10.1186/1742-2094-11-133] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/15/2014] [Indexed: 01/02/2023] Open
Abstract
Background Glaucomatous optic neuropathy, a leading cause of blindness, can progress despite control of intraocular pressure - currently the main risk factor and target for treatment. Glaucoma progression shares mechanisms with neurodegenerative disease, including microglia activation. In the present model of ocular hypertension (OHT), we have recently described morphological signs of retinal microglia activation and MHC-II upregulation in both the untreated contralateral eyes and OHT eyes. By using immunostaining, we sought to analyze and quantify additional signs of microglia activation and differences depending on the retinal layer. Methods Two groups of adult Swiss mice were used: age-matched control (naïve, n = 12), and lasered (n = 12). In the lasered animals, both OHT eyes and contralateral eyes were analyzed. Retinal whole-mounts were immunostained with antibodies against Iba-1, MHC-II, CD68, CD86, and Ym1. The Iba-1+ cell number in the plexiform layers (PL) and the photoreceptor outer segment (OS), Iba-1+ arbor area in the PL, and area of the retina occupied by Iba-1+ cells in the nerve fiber layer-ganglion cell layer (NFL-GCL) were quantified. Results The main findings in contralateral eyes and OHT eyes were: i) ameboid microglia in the NFL-GCL and OS; ii) the retraction of processes in all retinal layers; iii) a higher level of branching in PL and in the OS; iv) soma displacement to the nearest cell layers in the PL and OS; v) the reorientation of processes in the OS; vi) MHC-II upregulation in all retinal layers; vii) increased CD68 immunostaining; and viii) CD86 immunolabeling in ameboid cells. In comparison with the control group, a significant increase in the microglial number in the PL, OS, and in the area occupied by Iba-1+ cells in the NFL-GCL, and significant reduction of the arbor area in the PL. In addition, rounded Iba-1+ CD86+ cells in the NFL-GCL, OS and Ym1+ cells, and rod-like microglia in the NFL-GCL were restricted to OHT eyes. Conclusions Several quantitative and qualitative signs of microglia activation are detected both in the contralateral and OHT eyes. Such activation extended beyond the GCL, involving all retinal layers. Differences between the two eyes could help to elucidate glaucoma pathophysiology.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - José M Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Pab VI, 4a, Avenida Complutense s/n, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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Santiago AR, Baptista FI, Santos PF, Cristóvão G, Ambrósio AF, Cunha RA, Gomes CA. Role of microglia adenosine A(2A) receptors in retinal and brain neurodegenerative diseases. Mediators Inflamm 2014; 2014:465694. [PMID: 25132733 PMCID: PMC4124703 DOI: 10.1155/2014/465694] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/20/2014] [Indexed: 12/20/2022] Open
Abstract
Neuroinflammation mediated by microglial cells in the brain has been commonly associated with neurodegenerative diseases. Whether this microglia-mediated neuroinflammation is cause or consequence of neurodegeneration is still a matter of controversy. However, it is unequivocal that chronic neuroinflammation plays a role in disease progression and halting that process represents a potential therapeutic strategy. The neuromodulator adenosine emerges as a promising targeting candidate based on its ability to regulate microglial proliferation, chemotaxis, and reactivity through the activation of its G protein coupled A2A receptor (A2AR). This is in striking agreement with the ability of A2AR blockade to control several brain diseases. Retinal degenerative diseases have been also associated with microglia-mediated neuroinflammation, but the role of A2AR has been scarcely explored. This review aims to compare inflammatory features of Parkinson's and Alzheimer's diseases with glaucoma and diabetic retinopathy, discussing the therapeutic potential of A2AR in these degenerative conditions.
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Affiliation(s)
- Ana R. Santiago
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- AIBILI, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Filipa I. Baptista
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo F. Santos
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Gonçalo Cristóvão
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
| | - António F. Ambrósio
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- AIBILI, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Rodrigo A. Cunha
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Catarina A. Gomes
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
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de Sousa É, Walter LT, Higa GSV, Casado OAN, Kihara AH. Developmental and functional expression of miRNA-stability related genes in the nervous system. PLoS One 2013; 8:e56908. [PMID: 23700402 PMCID: PMC3659046 DOI: 10.1371/journal.pone.0056908] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 01/15/2013] [Indexed: 11/19/2022] Open
Abstract
In the nervous system, control of gene expression by microRNAs (miRNAs) has been investigated in fundamental processes, such as development and adaptation to ambient demands. The action of these short nucleotide sequences on specific genes depends on intracellular concentration, which in turn reflects the balance of biosynthesis and degradation. Whereas mechanisms underlying miRNA biogenesis has been investigated in recent studies, little is known about miRNA-stability related proteins. We first detected two genes in the retina that have been associated to miRNA stability, XRN2 and PAPD4. These genes are highly expressed during retinal development, however with distinct subcellular localization. We investigated whether these proteins are regulated during specific phases of the cell cycle. Combined analyses of nuclei position in neuroblastic layer and labeling using anti-cyclin D1 revealed that both proteins do not accumulate in S or M phases of the cell cycle, being poorly expressed in progenitor cells. Indeed, XRN2 and PAPD4 were observed mainly after neuronal differentiation, since low expression was also observed in astrocytes, endothelial and microglial cells. XRN2 and PAPD4 are expressed in a wide variety of neurons, including horizontal, amacrine and ganglion cells. To evaluate the functional role of both genes, we carried out experiments addressed to the retinal adaptation in response to different ambient light conditions. PAPD4 is upregulated after 3 and 24 hours of dark- adaptation, revealing that accumulation of this protein is governed by ambient light levels. Indeed, the fast and functional regulation of PAPD4 was not related to changes in gene expression, disclosing that control of protein levels occurs by post-transcriptional mechanisms. Furthermore, we were able to quantify changes in PAPD4 in specific amacrine cells after dark -adaptation, suggesting for circuitry-related roles in visual perception. In summary, in this study we first described the ontogenesis and functional expression of these two miRNA-stability related proteins in the retina.
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Affiliation(s)
- Érica de Sousa
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Santo André, SP, Brasil
| | - Lais Takata Walter
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Santo André, SP, Brasil
| | - Guilherme Shigueto Vilar Higa
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Santo André, SP, Brasil
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - Otávio Augusto Nocera Casado
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Santo André, SP, Brasil
| | - Alexandre Hiroaki Kihara
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Santo André, SP, Brasil
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
- * E-mail:
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13
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Müller Glia Cells Activation in Rat Retina After Optic Nerve Injury: Spatiotemporal Correlation with Transcription Initiation Factor IIB. J Mol Neurosci 2013; 51:37-46. [DOI: 10.1007/s12031-012-9941-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 11/21/2012] [Indexed: 10/27/2022]
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14
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Abstract
BACKGROUND Visual loss associated with brain damage, especially hypoxic-ischemic (HI) encephalopathy, is the most common cause of visual impairment in children in developed countries. We hypothesized that HI insults can cause long-term damage in immature eyes. METHODS In postnatal day 7 rat pups, HI was induced by unilateral common carotid artery ligation followed by hypoxia. Retina damage was assessed by electroretinography (ERG) and cell counting. Neuronal injury and astrogliosis were evaluated by terminal deoxynucleotidyl transferase nick-end labeling, cleaved caspase 3, ED1, and glial fibrillary acidic protein immunostaining. RESULTS We observed rapid and persistently extensive injuries in the ganglia cell layer (GCL), inner plexiform layer, and inner nuclear layer (INL) in ipsilateral retinas after HI injury, corresponding to the marked alteration in ERG. HI insult caused prominent microglial and Műller cell activation in ipsilateral inner retinas. Neuronal death in the GCL and INL after HI injury was mainly apoptotic, involving caspase-dependent pathways. CONCLUSION Our study demonstrated the first evidence of HI retinal damage at both the pathological and functional level using the Vannucci model in neonatal rats. Because retinal damage is often associated with HI injury, it is important to demonstrate that a particular neuroprotective strategy effectively preserves the retina in addition to the brain.
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Affiliation(s)
- Hsiu-Mei Huang
- Department of Ophthamology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
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15
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Pascale A, Drago F, Govoni S. Protecting the retinal neurons from glaucoma: lowering ocular pressure is not enough. Pharmacol Res 2012; 66:19-32. [PMID: 22433276 DOI: 10.1016/j.phrs.2012.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/28/2012] [Accepted: 03/05/2012] [Indexed: 01/01/2023]
Abstract
The retina is theater of a number of biochemical reactions allowing, within its layers, the conversion of light impulses into electrical signals. The axons of the last neuronal elements, the ganglion cells, form the optic nerve and transfer the signals to the brain. Therefore, an appropriate cellular communication, not only within the different retinal cells, but also between the retina itself and the other brain structures, is fundamental. One of the most diffuse pathologies affecting retinal function and communication, which thus reverberates in the whole visual system, is glaucoma. This insidious disease is characterized by a progressive optic nerve degeneration and sight loss which may finally lead to irreversible blindness. Nevertheless, the progressive nature of this pathology offers an opportunity for therapeutic intervention. To better understand the cellular processes implicated in the development of glaucoma useful to envision a targeted pharmacological strategy, this manuscript first examines the complex cellular and functional organization of the retina and subsequently identifies the targets sensitive to neurodegeneration. Within this context, high ocular pressure represents a key risk factor. However, recent literature findings highlight the concept that lowering ocular pressure is not enough to prevent/slow down glaucomatous damage, suggesting the importance of combining the hypotensive treatment with other pharmacological approaches, such as the use of neuroprotectants. Therefore, this important and more novel aspect is extensively considered in this review, also emphasizing the idea that the neuroprotective strategy should be extended to the entire visual system and not restricted to the retina.
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Affiliation(s)
- Alessia Pascale
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
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16
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The molecular basis of retinal ganglion cell death in glaucoma. Prog Retin Eye Res 2012; 31:152-81. [DOI: 10.1016/j.preteyeres.2011.11.002] [Citation(s) in RCA: 565] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 10/28/2011] [Accepted: 11/01/2011] [Indexed: 12/14/2022]
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17
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Salgado C, Vilson F, Miller NR, Bernstein SL. Cellular inflammation in nonarteritic anterior ischemic optic neuropathy and its primate model. ACTA ACUST UNITED AC 2012; 129:1583-91. [PMID: 22159678 DOI: 10.1001/archophthalmol.2011.351] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To correlate potential inflammatory responses in nonarteritic anterior ischemic optic neuropathy (NAION) with a lesion possessing many physiologic and histologic similarities from a model of nonhuman primate NAION (pNAION). METHODS Using immunohistochemistry and confocal microscopic analysis, we evaluated the relative numbers of inflammatory cell types in the single available clinical specimen of early NAION (21 days after event). We correlated this with the temporal inflammatory response occurring in optic nerve tissue at different times following pNAION induction. RESULTS In pNAION, there is a previously unsuspected infiltration of polymorphonuclear leukocytes occurring almost immediately after infarct induction, followed by invasion of ED1+ extrinsic macrophages, which peaks 5 weeks after infarct. Intrinsic microglia accumulate up to 70 days after induction in the area of primary axonal loss. The analyzed human NAION specimen was similar to 21-day pNAION tissue, with extrinsic macrophages and intrinsic microglial cells in the region of focal axon loss. CONCLUSIONS Cellular inflammation plays a major early role following white-matter (optic nerve) infarct, with both polymorphonuclear leukocyte and macrophage function involved in debris elimination and tissue remodeling. The optic nerve in NAION and its primate model are associated with early cellular inflammation, previously unsuspected, that may contribute to postinfarct optic nerve damage.
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Affiliation(s)
- Cristian Salgado
- Division of Neuro-Ophthalmology, Wilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, MD, USA
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18
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Wohl SG, Schmeer CW, Friese T, Witte OW, Isenmann S. In situ dividing and phagocytosing retinal microglia express nestin, vimentin, and NG2 in vivo. PLoS One 2011; 6:e22408. [PMID: 21850226 PMCID: PMC3151247 DOI: 10.1371/journal.pone.0022408] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 06/21/2011] [Indexed: 11/18/2022] Open
Abstract
Background Following injury, microglia become activated with subsets expressing nestin as well as other neural markers. Moreover, cerebral microglia can give rise to neurons in vitro. In a previous study, we analysed the proliferation potential and nestin re-expression of retinal macroglial cells such as astrocytes and Müller cells after optic nerve (ON) lesion. However, we were unable to identify the majority of proliferative nestin+ cells. Thus, the present study evaluates expression of nestin and other neural markers in quiescent and proliferating microglia in naïve retina and following ON transection in adult rats in vivo. Methodology/Principal Findings For analysis of cell proliferation and cells fates, rats received BrdU injections. Microglia in retinal sections or isolated cells were characterized using immunofluorescence labeling with markers for microglia (e.g., Iba1, CD11b), cell proliferation, and neural cells (e.g., nestin, vimentin, NG2, GFAP, Doublecortin etc.). Cellular analyses were performed using confocal laser scanning microscopy. In the naïve adult rat retina, about 60% of resting ramified microglia expressed nestin. After ON transection, numbers of nestin+ microglia peaked to a maximum at 7 days, primarily due to in situ cell proliferation of exclusively nestin+ microglia. After 8 weeks, microglia numbers re-attained control levels, but 20% were still BrdU+ and nestin+, although no further local cell proliferation occurred. In addition, nestin+ microglia co-expressed vimentin and NG2, but not GFAP or neuronal markers. Fourteen days after injury and following retrograde labeling of retinal ganglion cells (RGCs) with Fluorogold (FG), nestin+NG2+ microglia were positive for the dye indicating an active involvement of a proliferating cell population in phagocytosing apoptotic retinal neurons. Conclusions/Significance The current study provides evidence that in adult rat retina, a specific resident population of microglia expresses proteins of immature neural cells that are involved in injury-induced cell proliferation and phagocytosis while transdifferentiation was not observed.
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Affiliation(s)
- Stefanie G Wohl
- Hans Berger Clinic of Neurology, Jena University Hospital, Jena, Germany.
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19
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Cho KJ, Kim JH, Park HYL, Park CK. Glial cell response and iNOS expression in the optic nerve head and retina of the rat following acute high IOP ischemia-reperfusion. Brain Res 2011; 1403:67-77. [PMID: 21704308 DOI: 10.1016/j.brainres.2011.06.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 11/20/2022]
Abstract
Acute high IOP ischemia-reperfusion induces the loss of retinal ganglion cells, supporting the hypothesis that the condition of ischemia-reperfusion contributes to the induction and progression of glaucoma. This study investigated morphological changes, glial cell response, and expression of inducible nitric oxide synthase (iNOS) in the optic nerve head and retina of the rat following acute high IOP ischemia-reperfusion. A 60-min ischemic period was administered to the rat eye by raising the IOP, followed by a reperfusion period lasting 2, 5, or 7 days. Histological examination showed that acute high IOP ischemia-reperfusion injury produced optic nerve head and retina damage. In immunohistochemical staining, GFAP and OX-45 were limited to the ganglion cell layer (GCL) or inner nuclear layer (INL) of the control retina and increased to nearly all layers of the retina after acute high IOP ischemia-reperfusion. GFAP and OX-42 were detected at the control optic nerve heads and increased after acute high IOP ischemia-reperfusion. After acute high IOP ischemia-reperfusion, expression of iNOS increased, mostly at the GCL and INL of the retina and at the optic nerve head. Western blot analysis showed that expression of iNOS increased significantly, compared with the control, in the retina and optic nerve head after acute high IOP ischemia-reperfusion. Activation of glial cells and the up-regulation of iNOS may contribute to the damage of the retina and optic nerve head of the rat following acute high IOP ischemia-reperfusion.
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Affiliation(s)
- Kyong Jin Cho
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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20
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Bosco A, Steele MR, Vetter ML. Early microglia activation in a mouse model of chronic glaucoma. J Comp Neurol 2011; 519:599-620. [PMID: 21246546 DOI: 10.1002/cne.22516] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Changes in microglial cell activation and distribution are associated with neuronal decline in the central nervous system (CNS), particularly under pathological conditions. Activated microglia converge on the initial site of axonal degeneration in human glaucoma, yet their part in its pathophysiology remains unresolved. To begin with, it is unknown whether microglia activation precedes or is a late consequence of retinal ganglion cell (RGC) neurodegeneration. Here we address this critical element in DBA/2J (D2) mice, an established model of chronic inherited glaucoma, using as a control the congenic substrain DBA/2J Gpnmb(+/SjJ) (D2G), which is not affected by glaucoma. We analyzed the spatial distribution and timecourse of microglial changes in the retina, as well as within the proximal optic nerve prior to and throughout ages when neurodegeneration has been reported. Exclusively in D2 mice, we detected early microglia clustering in the inner central retina and unmyelinated optic nerve regions, with microglia activation peaking by 3 months of age. Between 5 and 8 months of age, activated microglia persisted and concentrated in the optic disc, but also localized to the retinal periphery. Collectively, our findings suggest microglia activation is an early alteration in the retina and optic nerve in D2 glaucoma, potentially contributing to disease onset or progression. Ultimately, detection of microglial activation may have value in early disease diagnosis, while modulation of microglial responses may alter disease progression.
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Affiliation(s)
- Alejandra Bosco
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84132, USA.
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21
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Leonelli M, Martins DO, Britto LRG. TRPV1 receptors are involved in protein nitration and Müller cell reaction in the acutely axotomized rat retina. Exp Eye Res 2010; 91:755-68. [PMID: 20826152 DOI: 10.1016/j.exer.2010.08.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 06/24/2010] [Accepted: 08/30/2010] [Indexed: 12/20/2022]
Abstract
We report here the protein expression of TRPV1 receptor in axotomized rat retinas and its possible participation in mechanisms involved in retinal ganglion cell (RGC) death. Adult rats were subjected to unilateral, intraorbital axotomy of the optic nerve, and the retinal tissue was removed for further processing. TRPV1 total protein expression decreased progressively after optic nerve transection, reaching 66.2% of control values 21 days after axotomy. The number of cells labeled for TRPV1 in the remnant GCL decreased after 21 days post-lesion (to 63%). Fluoro-Jade B staining demonstrated that the activation of TRPV1 in acutely-lesioned eyes elicited more intense neuronal degeneration in the GCL and in the inner nuclear layer than in sham-operated retinas. A single intraocular injection of capsazepine (100 μM), a TRPV1 antagonist, 5 days after optic nerve lesion, decreased the number of GFAP-expressing Müller cells (72.5% of control values) and also decreased protein nitration in the retinal vitreal margin (75.7% of control values), but did not affect lipid peroxidation. Furthermore, retinal explants were treated with capsaicin (100 μM), and remarkable protein nitration was then present, which was reduced by blockers of the constitutive and inducible nitric oxide synthases (7-NI and aminoguanidine, respectively). TRPV1 activation also increased GFAP expression, which was reverted by both TRPV1 antagonism with capsazepine and by 7-NI and aminoguanidine. Given that Müller cells do not express TRPV1, we suppose that the increased GFAP expression in these cells might be elicited by TRPV1 activation and by its indirect effect upon nitric oxide overproduction and peroxynitrite formation. We incubated Fluorogold pre-labeled retinal explants in the presence of capsazepine (1 μM) during 48 h. The numbers of surviving RGCs stained with fluorogold and the numbers of apoptotic cells in the GCL detected with TUNEL were similar in lesioned and control retinas. We conclude that TRPV1 receptor expression decreased after optic nerve injury due to death of TRPV1-containing cells. Furthermore, these data indicate that TRPV1 might be involved in intrinsic protein nitration and Müller cell reaction observed after optic nerve injury.
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Affiliation(s)
- Mauro Leonelli
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP 05508-900, Brazil.
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22
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Axonal degeneration, regeneration and ganglion cell death in a rodent model of anterior ischemic optic neuropathy (rAION). Exp Eye Res 2010; 91:286-92. [PMID: 20621651 DOI: 10.1016/j.exer.2010.05.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 05/08/2010] [Accepted: 05/25/2010] [Indexed: 12/19/2022]
Abstract
Using laser-induced photoactivation of intravenously administered rose Bengal in rats, we generated an ischemic infarction of the intrascleral portion of the optic nerve (ON) comparable to that which occurs in humans to investigate optic nerve axon degenerative events following optic nerve infarct and the potential for axon re-growth. Animals were euthanized at different times post infarct. Axon degeneration was evaluated with SMI312 immunolabeling, and GAP-43 immunostaining was used to identify axon regeneration. Terminal dUTP nick end labeling (TUNEL) was used to evaluate retinal ganglion cell (RGC) death. There was significant axon structural disruptinot ion at the anterior intrascleral portion of the ON by 3d post-infarct, extending to the posterior ON by 7d post-stroke. Destruction of normal axon structure and massive loss of axon fibers occurred by 2 weeks. GAP-43 immunoreactivity occurred in the anterior ON by 7d post-infarct, lasting 3-4 weeks, without extension past the primary ischemic lesion. TUNEL-positive cells in the RGC layer appeared by 7d post-insult. These results indicate that following induction of ischemic optic neuropathy, significant axon damage occurs by 3d post-infarct, with later neuronal death. Post-stroke adult rat retinal ganglion cells attempt to regenerate their axons, but this effort is restricted to the unmyelinated region of the anterior ON. These responses are important in understanding pathologic process that underlies human non-arteritic anterior ischemic optic neuropathy (NAION) and may guide both the appropriate treatment of NAION and the window of opportunity for such treatment.
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23
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Wohl SG, Schmeer CW, Kretz A, Witte OW, Isenmann S. Optic nerve lesion increases cell proliferation and nestin expression in the adult mouse eye in vivo. Exp Neurol 2009; 219:175-86. [DOI: 10.1016/j.expneurol.2009.05.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 04/01/2009] [Accepted: 05/08/2009] [Indexed: 11/28/2022]
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24
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Leonelli M, Martins DO, Kihara AH, Britto LRG. Ontogenetic expression of the vanilloid receptors TRPV1 and TRPV2 in the rat retina. Int J Dev Neurosci 2009; 27:709-18. [PMID: 19619635 DOI: 10.1016/j.ijdevneu.2009.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/06/2009] [Accepted: 07/11/2009] [Indexed: 01/13/2023] Open
Abstract
The present study aimed to analyze the gene and protein expression and the pattern of distribution of the vanilloid receptors TRPV1 and TRPV2 in the developing rat retina. During the early phases of development, TRPV1 was found mainly in the neuroblastic layer of the retina and in the pigmented epithelium. In the adult, TRPV1 was found in microglial cells, blood vessels, astrocytes and in neuronal structures, namely synaptic boutons of both retinal plexiform layers, as well as in cell bodies of the inner nuclear layer and the ganglion cell layer. The pattern of distribution of TRPV1 was mainly punctate, and there was higher TRPV1 labeling in the peripheral retina than in central regions. TRPV2 expression was quite distinct. Its expression was virtually undetectable by immunoblotting before P1, and that receptor was found by immunohistochemistry only by postnatal day 15 (P15). RNA and protein analysis showed that the adult levels are only reached by P60, which includes small processes in the retinal plexiform layers, and labeled cellular bodies in the inner nuclear layer and the ganglion cell layer. There was no overlapping between the signal observed for both receptors. In conclusion, our results showed that the patterns of distribution of TRPV1 and TRPV2 are different during the development of the rat retina, suggesting that they have specific roles in both visual processing and in providing specific cues to neural development.
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Affiliation(s)
- Mauro Leonelli
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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25
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Cui Q, Yin Y, Benowitz LI. The role of macrophages in optic nerve regeneration. Neuroscience 2009; 158:1039-48. [PMID: 18708126 PMCID: PMC2670061 DOI: 10.1016/j.neuroscience.2008.07.036] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/18/2008] [Accepted: 07/20/2008] [Indexed: 11/25/2022]
Abstract
Following injury to the nervous system, the activation of macrophages, microglia, and T-cells profoundly affects the ability of neurons to survive and to regenerate damaged axons. The primary visual pathway provides a well-defined model system for investigating the interactions between the immune system and the nervous system after neural injury. Following damage to the optic nerve in mice and rats, retinal ganglion cells, the projection neurons of the eye, normally fail to regenerate their axons and soon begin to die. Induction of an inflammatory response in the vitreous strongly enhances the survival of retinal ganglion cells and enables these cells to regenerate lengthy axons beyond the injury site. T cells modulate this response, whereas microglia are thought to contribute to the loss of retinal ganglion cells in this model and in certain ocular diseases. This review discusses the complex and sometimes paradoxical actions of blood-borne macrophages, resident microglia, and T-cells in determining the outcome of injury in the primary visual pathway.
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Affiliation(s)
- Q Cui
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, 147K Argyle Street, Kowloon, Hong Kong, PR China.
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26
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Schmid H, Herrmann T, Kohler K, Stett A. Neuroprotective effect of transretinal electrical stimulation on neurons in the inner nuclear layer of the degenerated retina. Brain Res Bull 2009; 79:15-25. [PMID: 19150490 DOI: 10.1016/j.brainresbull.2008.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2008] [Revised: 10/03/2008] [Accepted: 12/18/2008] [Indexed: 11/17/2022]
Abstract
Electrical stimulation has been shown to have neuroprotective effects on ganglion cells and photoreceptors in axotomized and dystrophic retinas from Royal College of Surgeons (RCS) rats. This study determined whether electrical stimulation also has a neuroprotective effect on cells in the inner nuclear layer (INL) of retinas. We cultivated retinas from adult RCS rats on microelectrode arrays and stimulated them continuously with 20 Hz for up to 5 days. Afterwards, we subjected them to quantitative immunohistochemical analysis. Using TUNEL assay we found that transretinal electrical stimulation (TRES) with charge densities within the range of 100-500 microC/cm2 reduced apoptosis of neurons in the INL of degenerated retinas from RCS -/- rats by 20% after 1 day of continuous stimulation. Antibody staining (OX-42, ED1) revealed a reduced activation of migroglial cells in RCS -/- and congenic control (RCS +/+) rat retinas by up to 50% after 1 day of stimulation. The effect of electrical stimulation on apoptosis and reduced activation of microglial cells was closely correlated with the strength and duration of the stimulation. The neuroprotective effect of TRES on neuronal cells in the INL of degenerated RCS rat retinas supports the idea that electrical stimulation may be a therapeutic option to delay the progression of retinal degeneration in patients suffering from retinitis pigmentosa.
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Affiliation(s)
- Heiko Schmid
- NMI Natural & Medical Sciences Institute at the University of Tuebingen, Markwiesenstr. 55, 72770 Reutlingen, Germany
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27
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Sobrado-Calvo P, Vidal-Sanz M, Villegas-Pérez MP. Rat retinal microglial cells under normal conditions, after optic nerve section, and after optic nerve section and intravitreal injection of trophic factors or macrophage inhibitory factor. J Comp Neurol 2007; 501:866-78. [PMID: 17311318 DOI: 10.1002/cne.21279] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Retinal microglial cells may have a role in both degeneration and neuroprotection of retinal ganglion cells (RGC) after optic nerve (ON) section. We have used NDPase enzymohistochemistry to label adult rat retinal microglial cells and have studied these cells under normal conditions, after left ON section, and after left ON section and eye puncture or intravitreal injection of different substances: vehicle, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin 3 (NT3), or macrophage inhibitory factor (MIF). Resident microglial cells are present in four layers in the adult rat retina: the nerve fiber layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and outer plexiform layer (OPL). Left ON section induces microglial activation in the ipsilateral and contralateral retina as manifested by stronger staining intensity in both retinas and increased microglial cell densities in the NFL, IPL, and GCL of the ipsilateral retina. Left ON section followed by left eye puncture or intravitreal injection increases microglial cell density in both retinas and induces changes in the microglial cells of the ipsilateral retina that vary depending on the substance injected: BDNF injections delay microglial activation, possibly through retinal ganglion cell neuroprotection, whereas NT3 partially inhibits microglial activation in the NFL; MIF injections have no clear effects on microglial activation. In conclusion, retinal microglial cells become activated after an ON section and react more intensely when the eye is also punctured or injected, and this response may be altered by using neurotrophic factors, although the effects of MIF are less clear.
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Affiliation(s)
- Paloma Sobrado-Calvo
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, 30100 Espinardo, Murcia, Spain
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Ju KR, Kim HS, Kim JH, Lee NY, Park CK. Retinal glial cell responses and Fas/FasL activation in rats with chronic ocular hypertension. Brain Res 2006; 1122:209-21. [PMID: 17045251 DOI: 10.1016/j.brainres.2006.09.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 09/02/2006] [Accepted: 09/05/2006] [Indexed: 12/31/2022]
Abstract
Responses in the retina post injury provoke glial reactions that are not completely understood. This study investigated the reaction of retinal glial cells and the expression and localization of the Fas and Fas-ligand (FasL) in rats with chronic ocular hypertension. Experimental glaucoma was induced in one eye of 60 Sprague-Dawley rats by cauterizing three episcleral vessels. It caused a moderate intraocular pressure (IOP) elevation and significant retinal ganglion cell (RGC) loss for at least 6 weeks in all animals. Immunohistochemical analysis revealed that the expression of GFAP and OX-42 increased in the injured retinae. Fas/FasL immunoreactivity was elevated in the microglia, and we also observed an incremental increase in Fas associated death domain (FADD) immunoreactivity in Müller glial cells and RGCs in the IOP-elevated retinae. The activation of glial cells and upregulation of Fas and FasL suggest that glial cells may contribute to Fas-mediated cell death in the neurodegeneration process of chronic ocular hypertensive retinal insult.
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Affiliation(s)
- Kwang Ro Ju
- Department of Ophthalmology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, Republic of Korea
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29
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Chang ML, Wu CH, Chien HF, Jiang-Shieh YF, Shieh JY, Wen CY. Microglia/macrophages responses to kainate-induced injury in the rat retina. Neurosci Res 2006; 54:202-12. [PMID: 16458383 DOI: 10.1016/j.neures.2005.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 11/25/2005] [Accepted: 11/29/2005] [Indexed: 10/25/2022]
Abstract
The present study was aimed to elucidate how retinal microglia/macrophages would respond to neuronal death after intravitreal kainate injection. An increased expression of the complement receptor type 3 (CR3) and an induction of the major histocompatibility complex (MHC) class II and ED-1 antigens were mainly observed in the inner retina after kainate injection. Prominent cell death revealed by Fluoro Jade B (FJB) staining and ultrastructural examination appeared at the inner border of the inner nuclear layer (INL) at 1 day post-injection. Interestingly, some immunoreactive cells appeared at the outer segment of photoreceptor layer (OSPRL) at different time intervals. Our quantitative analysis further showed that CR3 immunoreactivity was drastically increased peaking at 7 days but subsided thereafter. MHC class II and ED-1 immunoreactivities showed a moderate but steady increase peaking at 3 days and declined thereafter. Double labeling study further revealed that retinal microglia/macrophages expressed concurrently CR3 and ED-1 antigens (OX-42+/ED-1+) or MHC class II molecules (OX-42+/OX-6+) and remained branched in shape at early stage of kainate challenge. By electron microscopy, microglia/macrophages with CR3 immunoreactivity displayed abundant cytoplasm containing a few vesicles and phagosomes. Other cells ultrastructurally similar to Müller cells or astrocytes could also engulf exogenous substances. In conclusion, retinal microglia/macrophages responded vigorously to kainate-induced neuronal cell death that may also trigger the recruitment of macrophages from neighboring tissues and induce the phagocytotic activity of cells other than retinal microglia/macrophages.
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Affiliation(s)
- Min-Lin Chang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, 1, Section 1, Jen Ai Road, Taipei 100, Taiwan
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Zhang C, Lam TT, Tso MO. Heterogeneous populations of microglia/macrophages in the retina and their activation after retinal ischemia and reperfusion injury. Exp Eye Res 2005; 81:700-9. [PMID: 15967434 DOI: 10.1016/j.exer.2005.04.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 03/01/2005] [Accepted: 04/18/2005] [Indexed: 01/05/2023]
Abstract
Activation of Microglia/macrophages has been observed in ischemia-reperfusion injury of the brain. This study was undertaken to investigate the different subpopulations of microglia/macrophages in the normal rat retina and their activation after retinal ischemia. Retinal ischemia was induced by elevation of intraocular pressure to 120 mmHg for 60 min. Microglia/macrophages were identified on frozen retinal sections by four antibodies, namely OX42, 5D4, OX6 and ED1. In the normal retina, there were heterogeneous populations of resident microglia/macrophages as characterized by their differences in morphology, antigen expression and distribution. OX42+ cells had delicate processes and were located in the inner layers of the retina, while 5D4+ cells were highly ramified and mostly scattered in the inner plexiform layer (IPL) and the outer plexiform layer. Few amoeboid ED1+ cells were also seen in the ganglion cell layer and IPL. OX6+ (MHC-II antigen presenting) cells were not detected in the normal retinas. Double labeling with OX42 and 5D4 antibodies on normal retinal sections showed few microglia exhibited positive labeling with both OX42 and 5D4, while the majority of the microglia were labeled with either OX42 or 5D4 antibodies. After retinal ischemia single labeling with these antibodies showed increased number of these antigen-expressing cells, disappearance of normal cellular processes, and rounding or amoeboid like appearance of the cell bodies. At 1 day after ischemia, there was a significant infiltration of round OX42+, ED1+ and OX6+ cells with loss of the cellular processes in the inner retina. From 3 to 14 days, all subpopulations of microglia/macrophages differentiated cellular processes and became dendritic again. Double labeling on retinas after 1 day of recovery showed OX42+ cells were co-labeled with ED1+ or OX6+ cells, but not with 5D4+ cells. Scattered amoeboid OX42+, 5D4+, and ED1+ cells were noted in the subretinal space 3-14 days after ischemia. In summary, there were heterogeneous populations of resident microglia/macrophages in the normal inner retina and they were activated early after ischemia-reperfusion injury and exhibited different antigenic expression which were further altered in the recovery phase.
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Affiliation(s)
- Cheng Zhang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 N Wolfe Street, Rm 457, Woods Building, Baltimore, MD 21287-9238, USA.
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Sarra GM, Sarra FG, Schlichtenbrede FC, Trittibach P, Estermann S, Tsiroukis E, Ali RR, Luthert PJ, Reichel MB. Effect of steroidal and non-steroidal drugs on the microglia activation pattern and the course of degeneration in the retinal degeneration slow mouse. Ophthalmic Res 2005; 37:72-82. [PMID: 15746562 DOI: 10.1159/000084248] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Accepted: 08/18/2004] [Indexed: 11/19/2022]
Abstract
BACKGROUND In hereditary retinal degeneration, microglia cells become activated, migrate through the outer nuclear layer (ONL) and accumulate in the subretinal space. Although this inflammatory process is not likely to be responsible for the onset of photoreceptor apoptosis, cytotoxic substances secreted by activated microglia could potentially accelerate and perpetuate the degenerative process. Anti-inflammatory drugs have been shown to modulate the microglia response in neurodegenerative disorders and potentially ameliorate the disease progression in various animal model systems. In this study we wanted to test the impact of the most commonly used anti-inflammatory drugs (acetylsalicylate and prednisolone) on the microglia activation pattern, the rate of caspase-3-dependent photoreceptor apoptosis and the course of the degeneration in the retinal degeneration slow (rds) mouse retina. METHODS 169 pigmented rds mice and 30 CBA wild-type mice were used for this study. The treatment groups were injected daily with either acetylsalicylate (200 mg/kg) or prednisolone (2 mg/kg) i.p. from day 0 up to 3 months. Animals were sacrificed at days 10, 14, 16, 18, 20, 30, 40, 60 and 90. Cryoprotected frozen sections were immunostained with F4/80 and cleaved caspase-3 antibodies. The main outcome measures were the total microglia count in the subretinal space, the total cleaved caspase-3-positive cells in the ONL and the averaged number of photoreceptor rows in the midperipheral retina. RESULTS Neither acetylsalicylate nor prednisolone reduced subretinal microglia accumulation in the rds mouse degeneration model. Moreover, they aggravated migration and accumulation in the early time course. The apoptotic cascade started earlier and was more pronounced in both treatment groups compared to the control group. The pace of retinal degeneration was not reduced in the treatment groups compared to the untreated control. In contrast, acetylsalicylate did significantly accelerate the photoreceptor cell degeneration in comparison to the prednisolone (p < 0.001) and to the control group (p < 0.001). CONCLUSIONS Acetylsalicylate and prednisolone do not decrease the microglia response in the rds mouse and are not neuroprotective. More research is needed to clarify the molecular mechanisms which lead to photoreceptor cell death and to elucidate the complex role of microglia in inherited retinal degeneration.
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Affiliation(s)
- G M Sarra
- University Eye Clinic, Inselspital, CH-3010 Bern, Switzerland.
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Gregerson DS, Sam TN, McPherson SW. The Antigen-Presenting Activity of Fresh, Adult Parenchymal Microglia and Perivascular Cells from Retina. THE JOURNAL OF IMMUNOLOGY 2004; 172:6587-97. [PMID: 15153473 DOI: 10.4049/jimmunol.172.11.6587] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Although several observations show local T cell recognition of retinal Ag, there has been no direct demonstration that the APC were retinal derived, rather than recruited. In this study, CD45(+) cells isolated from immunologically quiescent murine retina were tested in vitro for functional evidence of Ag presentation to naive and Ag-experienced CD4 T cells specific for beta-galactosidase. Because CD45(+) cells from brain have been reported to be efficient APC, they were included for comparison. Measures of activation included changes in CD4, CD25, CD44, CD45RB, CD62L, CD69, caspase-3 activation, CFSE dilution, size, number of cells recovered, and cytokine production. Retinal CD45(+) cells gave no evidence of Ag-dependent TCR ligation in naive T cells, unlike splenic APC and CD45(+) cells from brain, which supported potent responses. Instead, addition of retinal CD45(+) cells to cocultures of naive 3E9 T cells plus splenic APC reduced the yield of activated T cells and cytokine production by limiting T cell activation at early time points. Ag-experienced T cells responded weakly to Ag presented by retinal CD45(+) cells. Activating the retinal cells with IFN-gamma, anti-CD40, or LPS incrementally increased their APC activity. Addition of neutralizing Abs to TGF-beta did not reveal suppressed retinal APC activity. Because retina lacks tissue equivalents of meninges and choroid plexus, rich sources of dendritic cells in brain, cells from retina may better represent the APC activity of fresh, adult CNS parenchymal and perivascular cells. The activity of the retinal CD45(+) cells appears to be directed to limiting T cell responses.
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Affiliation(s)
- Dale S Gregerson
- Department of Ophthalmology, University of Minnesota, Minneapolis, MN 55455, USA.
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