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The Flavone Cirsiliol from Salvia x jamensis Binds the F 1 Moiety of ATP Synthase, Modulating Free Radical Production. Cells 2022; 11:cells11193169. [PMID: 36231131 PMCID: PMC9562182 DOI: 10.3390/cells11193169] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/25/2022] [Accepted: 10/04/2022] [Indexed: 11/16/2022] Open
Abstract
Several studies have shown that mammalian retinal rod outer segments (OS) are peculiar structures devoid of mitochondria, characterized by ectopic expression of the molecular machinery for oxidative phosphorylation. Such ectopic aerobic metabolism would provide the chemical energy for the phototransduction taking place in the OS. Natural polyphenols include a large variety of molecules having pleiotropic effects, ranging from anti-inflammatory to antioxidant and others. Our goal in the present study was to investigate the potential of the flavonoid cirsiliol, a trihydroxy-6,7-dimethoxyflavone extracted from Salvia x jamensis, in modulating reactive oxygen species production by the ectopic oxidative phosphorylation taking place in the OS. Our molecular docking analysis identified cirsiliol binding sites inside the F1 moiety of the nanomotor F1Fo-ATP synthase. The experimental approach was based on luminometry, spectrophotometry and cytofluorimetry to evaluate ATP synthesis, respiratory chain complex activity and H2O2 production, respectively. The results showed significant dose-dependent inhibition of ATP production by cirsiliol. Moreover, cirsiliol was effective in reducing the free radical production by the OS exposed to ambient light. We report a considerable protective effect of cirsiliol on the structural stability of rod OS, suggesting it may be considered a promising compound against oxidative stress.
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Ravera S, Esposito A, Degan P, Caicci F, Manni L, Liguori A, Bisio A, Iobbi V, Schito A, Traverso CE, Panfoli I. The diterpene Manool extracted from Salvia tingitana lowers free radical production in retinal rod outer segments by inhibiting the extramitochondrial F 1 F o ATP synthase. Cell Biochem Funct 2021; 39:528-535. [PMID: 33472276 DOI: 10.1002/cbf.3618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/17/2020] [Accepted: 12/28/2020] [Indexed: 11/05/2022]
Abstract
Uncontrolled oxidative stress production, especially in the outer retina is one of the causes of retinal degenerations. Mitochondria are considered the principal source of oxidative stress. However, a Reactive Oxygen Intermediates (ROI) production in the retinal photoreceptor layer seems to depend also on the expression of an extramitochondrial oxidative phosphorylation (OxPhos) machinery in the rod outer segments (OS). In fact, OS conduct aerobic metabolism, producing ATP through oxygen consumption, although it is devoid of mitochondria. As diterpenes display an antioxidant effect, we have evaluated the effect Manool, extracted from Salvia tingitana, on the extramitochondrial OxPhos and the ROI production in the retinal rod OS. Results confirm that the OxPhos machinery is ectopically expressed in the OS and that F1 Fo -ATP synthase is a target of Manool, which inhibited the OS ATP synthesis, binding the F1 moiety with high affinity, as analysed by molecular docking. Moreover, the overall slowdown of OxPhos metabolism reduced the ROI production elicited in the OS by light exposure, in vitro. In conclusion, data are consistent with the antioxidant properties of Salvia spp., suggesting its ability to lower oxidative stress production, a primary risk factor for degenerative retinal diseases. SIGNIFICANCE OF THE STUDY: Here we show that Manool, a diterpene extracted from Salvia tingitana has the potential to lower the free radical production by light-exposed rod outer segments in vitro, by specifically targeting the rod OS F1 Fo -ATP synthase belonging to the extramitochondrial OxPhos expressed on the disk membrane. The chosen experimental model allowed to show that the rod OS is a primary producer of oxidative stress linked to the pathogenesis of degenerative retinal diseases. Data are also consistent with the antioxidant and anti-inflammatory action of Salvia spp., suggesting a beneficial effect also in vivo.
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Affiliation(s)
- Silvia Ravera
- Dipartimento di Medicina Sperimentale, Università di Genova, Genova, Italy
| | - Alfonso Esposito
- Centro di Biologia Integrata (CIBIO), Università di Trento, Trento, Italy
| | - Paolo Degan
- UOC Mutagenesi, IRCCS Policlinico San Martino -IST (Istituto Nazionale per la Ricerca sul Cancro), Genova, Italy
| | - Federico Caicci
- Dipartimento di Biologia, Università di Padova, Padova, Italy
| | - Lucia Manni
- Dipartimento di Biologia, Università di Padova, Padova, Italy
| | - Anna Liguori
- Dipartimento di Farmacia (DIFAR), Università di Genova, Genova, Italy
| | - Angela Bisio
- Dipartimento di Farmacia (DIFAR), Università di Genova, Genova, Italy
| | - Valeria Iobbi
- Dipartimento di Farmacia (DIFAR), Università di Genova, Genova, Italy
| | - Anna Schito
- Dipartimento di Scienze Chirurgiche e Diagnostiche Integrate (DISC), Sezione di Microbiologia, Università di Genova, Genova, Italy
| | | | - Isabella Panfoli
- Dipartimento di Farmacia (DIFAR), Università di Genova, Genova, Italy
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Ravera S, Esposito A, Degan P, Caicci F, Calzia D, Perrotta E, Manni L, Bisio A, Iobbi V, Schito A, Traverso CE, Panfoli I. Sclareol modulates free radical production in the retinal rod outer segment by inhibiting the ectopic f 1f o-atp synthase. Free Radic Biol Med 2020; 160:368-375. [PMID: 32853720 DOI: 10.1016/j.freeradbiomed.2020.08.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/15/2020] [Accepted: 08/18/2020] [Indexed: 01/06/2023]
Abstract
We have previously shown that the retinal rod outer segments (OS) produce reactive oxygen species in the function of illumination in vitro, establishing a relationship among the extra-mitochondrial oxidative phosphorylation and phototransduction. This source of oxidative stress in the OS can be modulated by polyphenols, acting as inhibitors of F1Fo-ATP synthase. The present study aimed at exploring whether sclareol, a diterpene, interacts with F1Fo-ATP synthase mitigating the light-induced free radical production in the rod OS. Characterization of bovine retinal sections was conducted by immunogold analysis. Reactive oxygen intermediates production, oxygen consumption, the activity of the four respiratory complexes and ATP synthesis were evaluated in purified bovine rod OS. Molecular docking analyses were also conducted. Sclareol reduced free radical production by light-exposed rod OS. Such antioxidant effect was associated with an inhibition of the respiratory complexes and oxygen consumption (OCR), in coupled conditions. Sclareol also inhibited the rod OS ATP synthetic ability. Since the inhibitor effect on respiratory complexes and OCR is not observed in uncoupled conditions, it is supposed that the modulating effect of sclareol on the ectopic oxidative phosphorylation in the rod OS targets specifically the F1Fo-ATP synthase. This hypothesis is confirmed by the in silico molecular docking analyses, which shows that sclareol binds the F1 moiety of ATP synthase with high affinity. In conclusion, a beneficial effect of sclareol can be envisaged as a modulator of oxidative stress in the photoreceptor, a risk factor for the degenerative retinal diseases, suggestive of its potential beneficial action also in vivo.
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Affiliation(s)
- Silvia Ravera
- Dipartimento di Medicina Sperimentale, Università di Genoa, Via De Toni 14, 16132, Genova, Italy
| | - Alfonso Esposito
- Centro di Biologia Integrata (CIBIO), Università di Trento, Via Sommarive, 9, Povo, 38123, Trento, Italy
| | - Paolo Degan
- UOC Mutagenesi, IRCCS Policlinico San Martino -IST, Istituto Nazionale per La Ricerca Sul Cancro), Largo Rosanna Benzi 10, 16132, Genova, Italy
| | - Federico Caicci
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35121, Padova, Italy
| | - Daniela Calzia
- Dipartimento di Farmacia (DIFAR), Università di Genova, V.le Benedetto XV 3, 16132, Genova, Italy
| | - Eleonora Perrotta
- Dipartimento di Medicina Sperimentale, Università di Genoa, Via De Toni 14, 16132, Genova, Italy
| | - Lucia Manni
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35121, Padova, Italy
| | - Angela Bisio
- Dipartimento di Farmacia (DIFAR), Università di Genova, V.le Benedetto XV 3, 16132, Genova, Italy
| | - Valeria Iobbi
- Dipartimento di Farmacia (DIFAR), Università di Genova, V.le Benedetto XV 3, 16132, Genova, Italy
| | - Anna Schito
- Dipartimento di Scienze Chirurgiche e Diagnostiche Integrate (DISC), Sezione di Microbiologia, Università di Genova, Largo Rosanna Benzi 8, 16145, Genova, Italy
| | - Carlo Enrico Traverso
- Clinica Oculistica, (DINOGMI) Università di Genova, V.le Benedetto XV 6, 16132, Genova, Italy
| | - Isabella Panfoli
- Dipartimento di Farmacia (DIFAR), Università di Genova, V.le Benedetto XV 3, 16132, Genova, Italy.
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An In-Vitro Cell Model of Intracellular Protein Aggregation Provides Insights into RPE Stress Associated with Retinopathy. Int J Mol Sci 2020; 21:ijms21186647. [PMID: 32932802 PMCID: PMC7555953 DOI: 10.3390/ijms21186647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/30/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022] Open
Abstract
Impaired cargo trafficking and the aggregation of intracellular macromolecules are key features of neurodegeneration, and a hallmark of aged as well as diseased retinal pigment epithelial (RPE) cells in the eye. Here, photoreceptor outer segments (POS), which are internalized daily by RPE cells, were modified by UV-irradiation to create oxidatively modified POS (OxPOS). Oxidative modification was quantified by a protein carbonyl content assay. Human ARPE-19 cells were synchronously pulsed with POS or OxPOS to study whether oxidatively modified cargos can recapitulate features of RPE pathology associated with blinding diseases. Confocal immunofluorescence microscopy analysis showed that OxPOS was trafficked to LAMP1, LAMP2 lysosomes and to LC3b autophagy vacuoles. Whilst POS were eventually degraded, OxPOS cargos were sequestered in late compartments. Co-localization of OxPOS was also associated with swollen autolysosomes. Ultrastructural analysis revealed the presence of electron-dense OxPOS aggregates in RPE cells, which appeared to be largely resistant to degradation. Measurement of cellular autofluorescence, using parameters used to assess fundus autofluorescence (FAF) in age-related macular disease (AMD) patients, revealed that OxPOS contributed significantly to a key feature of aged and diseased RPE. This in vitro cell model therefore represents a versatile tool to study disease pathways linked with RPE damage and sight-loss.
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Bruschi M, Bartolucci M, Petretto A, Calzia D, Caicci F, Manni L, Traverso CE, Candiano G, Panfoli I. Differential expression of the five redox complexes in the retinal mitochondria or rod outer segment disks is consistent with their different functionality. FASEB Bioadv 2020; 2:315-324. [PMID: 32395704 PMCID: PMC7211042 DOI: 10.1096/fba.2019-00093] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 11/27/2019] [Accepted: 03/05/2020] [Indexed: 12/28/2022] Open
Abstract
PURPOSE The retinal rod outer segment (OS) disk membranes, devoid of mitochondria, conducts oxidative phosphorylation (OxPhos). This study aimed at identifying which proteins expressed in the retinal rod OS disks determined the considerable adenosine-5'-triphosphate production and oxygen consumption observed in comparison with retinal mitochondria. PROCEDURES Characterization was conducted by immunogold transmission electron microscopy on retinal sections. OxPhos was studied by oximetry and luminometry. The proteomes of OS disks and mitochondria purified from bovine retinas were studied by mass spectrometry. Statistical and bioinformatic analyses were conducted by univariate, multivariate, and machine learning methods. RESULTS Weighted gene coexpression network analysis identified two protein expression profile modules functionally associated with either retinal mitochondria or disk samples, in function of a strikingly different ability of each sample to utilized diverse substrate for F1Fo-ATP synthase. The OS disk proteins correlated better than mitochondria with the tricarboxylic acids cycle and OxPhos proteins. CONCLUSIONS The differential enrichment of the expression profile of the OxPhos proteins in the disks versus mitochondria suggests that these proteins may represent a true proteome component of the former, with different functionality. These findings may shed new light on the pathogenesis of rod-driven retinal degenerative diseases.
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Affiliation(s)
- Maurizio Bruschi
- Laboratory of Molecular NephrologyIstituto Giannina GasliniGenoaItaly
| | - Martina Bartolucci
- Laboratory of Mass Spectrometry‐Core FacilitiesIstituto Giannina GasliniGenovaItaly
| | - Andrea Petretto
- Laboratory of Mass Spectrometry‐Core FacilitiesIstituto Giannina GasliniGenovaItaly
| | - Daniela Calzia
- Dipartimento di Farmacia‐DIFARUniversità di GenovaGenoaItaly
| | | | - Lucia Manni
- Department of BiologyUniversità di PadovaPadovaItaly
| | - Carlo Enrico Traverso
- Clinica Oculistica, (Di.N.O.G.M.I.) Università Department of Intensive Care di GenovaIRCCS Azienda Ospedaliera Universitaria San Martino‐ISTGenoaItaly
| | - Giovanni Candiano
- Laboratory of Molecular NephrologyIstituto Giannina GasliniGenoaItaly
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Photobiomodulation Mediates Neuroprotection against Blue Light Induced Retinal Photoreceptor Degeneration. Int J Mol Sci 2020; 21:ijms21072370. [PMID: 32235464 PMCID: PMC7177783 DOI: 10.3390/ijms21072370] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/21/2020] [Accepted: 03/27/2020] [Indexed: 12/12/2022] Open
Abstract
Potent neuroprotective effects of photobiomodulation with 670 nm red light (RL) have been demonstrated in several models of retinal disease. RL improves mitochondrial metabolism, reduces retinal inflammation and oxidative cell stress, showing its ability to enhance visual function. However, the current knowledge is limited to the main hypothesis that the respiratory chain complex IV, cytochrome c oxidase, serves as the primary target of RL. Here, we demonstrate a comprehensive cellular, molecular, and functional characterization of neuroprotective effects of 670 nm RL and 810 nm near-infrared light (NIRL) on blue light damaged murine primary photoreceptors. We show that respiratory chain complexes I and II are additional PBM targets, besides complex IV, leading to enhanced mitochondrial energy metabolism. Accordingly, our study identified mitochondria related RL- and NIRL-triggered defense mechanisms promoting photoreceptor neuroprotection. The observed improvement of mitochondrial and extramitochondrial respiration in both inner and outer segments is linked with reduced oxidative stress including its cellular consequences and reduced mitochondria-induced apoptosis. Analysis of regulatory mechanisms using gene expression analysis identified upregulation α-crystallins that indicate enhanced production of proteins with protective functions that point to the rescued mitochondrial function. The results support the hypothesis that energy metabolism is a major target for retinal light therapy.
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Sinha T, Ikelle L, Naash MI, Al-Ubaidi MR. The Intersection of Serine Metabolism and Cellular Dysfunction in Retinal Degeneration. Cells 2020; 9:cells9030674. [PMID: 32164325 PMCID: PMC7140600 DOI: 10.3390/cells9030674] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
In the past, the importance of serine to pathologic or physiologic anomalies was inadequately addressed. Omics research has significantly advanced in the last two decades, and metabolomic data of various tissues has finally brought serine metabolism to the forefront of metabolic research, primarily for its varied role throughout the central nervous system. The retina is one of the most complex neuronal tissues with a multitude of functions. Although recent studies have highlighted the importance of free serine and its derivatives to retinal homeostasis, currently few reviews exist that comprehensively analyze the topic. Here, we address this gap by emphasizing how and why the de novo production and demand for serine is exceptionally elevated in the retina. Many basic physiological functions of the retina require serine. Serine-derived sphingolipids and phosphatidylserine for phagocytosis by the retinal pigment epithelium (RPE) and neuronal crosstalk of the inner retina via D-serine require proper serine metabolism. Moreover, serine is involved in sphingolipid–ceramide balance for both the outer retina and the RPE and the reductive currency generation for the RPE via serine biosynthesis. Finally and perhaps the most vital part of serine metabolism is free radical scavenging in the entire retina via serine-derived scavengers like glycine and GSH. It is hard to imagine that a single tissue could have such a broad and extensive dependency on serine homeostasis. Any dysregulation in serine mechanisms can result in a wide spectrum of retinopathies. Therefore, most critically, this review provides a strong argument for the exploration of serine-based clinical interventions for retinal pathologies.
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Affiliation(s)
| | | | - Muna I. Naash
- Correspondence: (M.I.N.); (M.R.A.-U.); Tel.: +1-713-743-1651 (M.I.N.); Fax: +1-713-743-0226 (M.I.N.)
| | - Muayyad R. Al-Ubaidi
- Correspondence: (M.I.N.); (M.R.A.-U.); Tel.: +1-713-743-1651 (M.I.N.); Fax: +1-713-743-0226 (M.I.N.)
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8
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Petrov AM, Astafev AA, Mast N, Saadane A, El-Darzi N, Pikuleva IA. The Interplay between Retinal Pathways of Cholesterol Output and Its Effects on Mouse Retina. Biomolecules 2019; 9:biom9120867. [PMID: 31842366 PMCID: PMC6995521 DOI: 10.3390/biom9120867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/03/2019] [Accepted: 12/10/2019] [Indexed: 12/14/2022] Open
Abstract
In mammalian retina, cholesterol excess is mainly metabolized to oxysterols by cytochromes P450 27A1 (CYP27A1) and 46A1 (CYP46A1) or removed on lipoprotein particles containing apolipoprotein E (APOE). In contrast, esterification by sterol-O-acyltransferase 1 (SOAT) plays only a minor role in this process. Accordingly, retinal cholesterol levels are unchanged in Soat1-/- mice but are increased in Cyp27a1-/-Cyp46a1-/- and Apoe-/- mice. Herein, we characterized Cyp27a1-/-Cyp46a1-/-Soat1-/- and Cyp27a1-/-Cyp46a1-/-Apoe-/- mice. In the former, retinal cholesterol levels, anatomical gross structure, and vasculature were normal, yet the electroretinographic responses were impaired. Conversely, in Cyp27a1-/-Cyp46a1-/-Apoe-/- mice, retinal cholesterol levels were increased while anatomical structure and vasculature were unaffected with only male mice showing a decrease in electroretinographic responses. Sterol profiling, qRT-PCR, proteomics, and transmission electron microscopy mapped potential compensatory mechanisms in the Cyp27a1-/-Cyp46a1-/-Soat1-/- and Cyp27a1-/-Cyp46a1-/-Apoe-/- retina. These included decreased cholesterol biosynthesis along with enhanced formation of intra- and extracellular vesicles, possibly a reserve mechanism for lowering retinal cholesterol. In addition, there was altered abundance of proteins in Cyp27a1-/-Cyp46a1-/-Soat1-/- mice that can affect photoreceptor function, survival, and retinal energy homeostasis (glucose and fatty acid metabolism). Therefore, the levels of retinal cholesterol do not seem to predict retinal abnormalities, and it is rather the network of compensatory mechanisms that appears to determine retinal phenotype.
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9
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García-Ayuso D, Di Pierdomenico J, Vidal-Sanz M, Villegas-Pérez MP. Retinal Ganglion Cell Death as a Late Remodeling Effect of Photoreceptor Degeneration. Int J Mol Sci 2019; 20:ijms20184649. [PMID: 31546829 PMCID: PMC6770703 DOI: 10.3390/ijms20184649] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/09/2019] [Accepted: 09/17/2019] [Indexed: 12/16/2022] Open
Abstract
Inherited or acquired photoreceptor degenerations, one of the leading causes of irreversible blindness in the world, are a group of retinal disorders that initially affect rods and cones, situated in the outer retina. For many years it was assumed that these diseases did not spread to the inner retina. However, it is now known that photoreceptor loss leads to an unavoidable chain of events that cause neurovascular changes in the retina including migration of retinal pigment epithelium cells, formation of “subretinal vascular complexes”, vessel displacement, retinal ganglion cell (RGC) axonal strangulation by retinal vessels, axonal transport alteration and, ultimately, RGC death. These events are common to all photoreceptor degenerations regardless of the initial trigger and thus threaten the outcome of photoreceptor substitution as a therapeutic approach, because with a degenerating inner retina, the photoreceptor signal will not reach the brain. In conclusion, therapies should be applied early in the course of photoreceptor degeneration, before the remodeling process reaches the inner retina.
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Affiliation(s)
- Diego García-Ayuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
| | - Johnny Di Pierdomenico
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
| | - María P Villegas-Pérez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
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10
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Tao JX, Zhou WC, Zhu XG. Mitochondria as Potential Targets and Initiators of the Blue Light Hazard to the Retina. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6435364. [PMID: 31531186 PMCID: PMC6721470 DOI: 10.1155/2019/6435364] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/18/2019] [Accepted: 07/25/2019] [Indexed: 12/20/2022]
Abstract
Commercially available white light-emitting diodes (LEDs) have an intense emission in the range of blue light, which has raised a range of public concerns about their potential risks as retinal hazards. Distinct from other visible light components, blue light is characterized by short wavelength, high energy, and strong penetration that can reach the retina with relatively little loss in damage potential. Mitochondria are abundant in retinal tissues, giving them relatively high access to blue light, and chromophores, which are enriched in the retina, have many mitochondria able to absorb blue light and induce photochemical effects. Therefore, excessive exposure of the retina to blue light tends to cause ROS accumulation and oxidative stress, which affect the structure and function of the retinal mitochondria and trigger mitochondria-involved death signaling pathways. In this review, we highlight the essential roles of mitochondria in blue light-induced photochemical damage and programmed cell death in the retina, indicate directions for future research and preventive targets in terms of the blue light hazard to the retina, and suggest applying LED devices in a rational way to prevent the blue light hazard.
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Affiliation(s)
- Jin-Xin Tao
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Department of Clinical Medicine, The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Wen-Chuan Zhou
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Department of Clinical Medicine, The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Xin-Gen Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
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11
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Reactive Oxygen Species-Mediated Damage of Retinal Neurons: Drug Development Targets for Therapies of Chronic Neurodegeneration of the Retina. Int J Mol Sci 2018; 19:ijms19113362. [PMID: 30373222 PMCID: PMC6274960 DOI: 10.3390/ijms19113362] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 02/06/2023] Open
Abstract
The significance of oxidative stress in the development of chronic neurodegenerative diseases of the retina has become increasingly apparent in recent years. Reactive oxygen species (ROS) are free radicals produced at low levels as a result of normal cellular metabolism that are ultimately metabolized and detoxified by endogenous and exogenous mechanisms. In the presence of oxidative cellular stress, ROS are produced in excess, resulting in cellular injury and death and ultimately leading to tissue and organ dysfunction. Recent studies have investigated the role of excess ROS in the pathogenesis and development of chronic neurodegenerative diseases of the retina including glaucoma, diabetic retinopathy, and age-related macular degeneration. Findings from these studies are promising insofar as they provide clear rationales for innovative treatment and prevention strategies of these prevalent and disabling diseases where currently therapeutic options are limited. Here, we briefly outline recent developments that have contributed to our understanding of the role of ROS in the pathogenesis of chronic neurodegenerative diseases of the retina. We then examine and analyze the peer-reviewed evidence in support of ROS as targets for therapy development in the area of chronic neurodegeneration of the retina.
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12
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Calzia D, Degan P, Caicci F, Bruschi M, Manni L, Ramenghi LA, Candiano G, Traverso CE, Panfoli I. Modulation of the rod outer segment aerobic metabolism diminishes the production of radicals due to light absorption. Free Radic Biol Med 2018; 117:110-118. [PMID: 29378336 DOI: 10.1016/j.freeradbiomed.2018.01.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 01/17/2018] [Accepted: 01/23/2018] [Indexed: 12/19/2022]
Abstract
Oxidative stress is a primary risk factor for both inflammatory and degenerative retinopathies. Our previous data on blue light-irradiated retinas demonstrated an oxidative stress higher in the rod outer segment (OS) than in the inner limb, leading to impairment of the rod OS extra-mitochondrial aerobic metabolism. Here the oxidative metabolism and Reactive Oxygen Intermediates (ROI) production was evaluated in purified bovine rod OS in function of exposure to different illumination conditions. A dose response was observed to varying light intensities and duration in terms of both ROI production and ATP synthesis. Pretreatment with resveratrol, inhibitor of F1Fo-ATP synthase, or metformin, inhibitor of the respiratory complex I, significantly diminished the ROI production. Metformin also diminished the rod OS Complex I activity and reduced the maximal OS response to light in ATP production. Data show for the first time the relationship existing in the rod OS between its -aerobic- metabolism, light absorption, and ROI production. A beneficial effect was exerted by metformin and resveratrol, in modulating the ROI production in the illuminated rod OS, suggestive of their beneficial action also in vivo. Data shed new light on preventative interventions for cone loss secondary to rod damage due to oxidative stress.
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Affiliation(s)
- Daniela Calzia
- Dipartimento di Farmacia-DIFAR,-Biochemistry Lab., University of Genoa, V.le Benedetto XV 3, 16132 Genova, Italy.
| | - Paolo Degan
- UOC Mutagenesi, IRCCS AOU San Martino - IST (Istituto Nazionale per la Ricerca sul Cancro), Genova, Italy
| | - Federico Caicci
- Department of Biology, Università di Padova, via U. Bassi 58/B, 35121 Padova, Italy
| | - Maurizio Bruschi
- Laboratory of Pathophysiology of Uremia, Istituto Giannina Gaslini, Genova, Italy
| | - Lucia Manni
- Department of Biology, Università di Padova, via U. Bassi 58/B, 35121 Padova, Italy
| | - Luca A Ramenghi
- Neonatal Intensive Care Unit, U.O.S. Malattie Metaboliche, V.le Benedetto XV 6, Genova, Italy
| | - Giovanni Candiano
- Neonatal Intensive Care Unit, U.O.S. Malattie Metaboliche, V.le Benedetto XV 6, Genova, Italy
| | - Carlo Enrico Traverso
- Clinica Oculistica, (DINOGMI) University of Genoa, V.le Benedetto XV 6, Genova, Italy
| | - Isabella Panfoli
- Dipartimento di Farmacia-DIFAR,-Biochemistry Lab., University of Genoa, V.le Benedetto XV 3, 16132 Genova, Italy
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13
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Bruschi M, Petretto A, Caicci F, Bartolucci M, Calzia D, Santucci L, Manni L, Ramenghi LA, Ghiggeri G, Traverso CE, Candiano G, Panfoli I. Proteome of Bovine Mitochondria and Rod Outer Segment Disks: Commonalities and Differences. J Proteome Res 2018; 17:918-925. [PMID: 29299929 DOI: 10.1021/acs.jproteome.7b00741] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The retinal rod outer segment (OS) is a stack of disks surrounded by the plasma membrane, housing proteins related to phototransduction, as well as mitochondrial proteins involved in oxidative phosphorylation (OxPhos). This prompted us to compare the proteome of bovine OS disks and mitochondria to assess the significant top gene signatures of each sample. The two proteomes, obtained by LTQ-Orbitrap Velos mass spectrometry, were compared by statistical analyses. In total, 4139 proteins were identified, 2045 of which overlapping in the two sets. Nonhierarchical Spearman's correlogram revealed that the groups were clearly discriminated. Partial least square discriminant plus support vector machine analysis identified the major discriminative proteins, implied in phototransduction and lipid metabolism, respectively. Gene Ontology analysis identified top gene signatures of the disk proteome, enriched in vesiculation, glycolysis, and OxPhos proteins. The tricarboxylic acid cycle and the electron transport proteins were similarly enriched in the two samples, but the latter was up regulated in disks. Data suggest that the mitochondrial OxPhos proteins may represent a true OS proteome component, outside the mitochondrion. This knowledge may help the scientific community in the further studies of retinal physiology and pathology.
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Affiliation(s)
| | | | - Federico Caicci
- Department of Biology, Università di Padova , 35121 Padova, Italy
| | | | - Daniela Calzia
- Dipartimento di Farmacia-DIFAR, Università di Genova , 16132 Genoa, Italy
| | | | - Lucia Manni
- Department of Biology, Università di Padova , 35121 Padova, Italy
| | | | | | - Carlo E Traverso
- Clinica Oculistica, (Di.N.O.G.M.I.) Università Department of Intensive Care di Genova, IRCCS Azienda Ospedaliera Universitaria San Martino-IST , 16132 Genoa, Italy
| | | | - Isabella Panfoli
- Dipartimento di Farmacia-DIFAR, Università di Genova , 16132 Genoa, Italy
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14
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Zhu W, Meng YF, Xing Q, Tao JJ, Lu J, Wu Y. Identification of lncRNAs involved in biological regulation in early age-related macular degeneration. Int J Nanomedicine 2017; 12:7589-7602. [PMID: 29089757 PMCID: PMC5655033 DOI: 10.2147/ijn.s140275] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background Age-related macular degeneration (AMD) is one of the most common causes of adult blindness in developed countries. However, the role of long noncoding RNAs (lncRNAs) in the development and progression of early AMD is unclear. Methods We established the lncRNA profile of early AMD by reannotation of microarrays from the gene expression omnibus database. Quantitative real-time polymerase chain reaction was used to determine the expression of selected lncRNAs. Results The expression profiles of 9 cases of AMD and 7 controls were studied. A total of 266 differentially expressed genes (DEGs) were detected (94 upregulated and 172 downregulated). Among all the DEGs, 64 were lncRNAs. Advanced bioinformatics analyses demonstrated that differentially expressed lncRNAs could play significant roles in visual perception, sensory perception of light stimulus, and cognition. The pathway analyses showed that the two most significantly influenced Kyoto Encyclopedia of Genes and Genomes pathways were those of phototransduction and purine metabolism. By the analyses of the key lncRNAs, it was found that RP11-234O6.2 was downregulated in the aging retinal pigment epithelium (RPE) cellular model. Exogenous RP11-234O6.2 treatment led to increased cell viability and improved apoptosis but it did not affect the cell migration ability of aging RPE cells. Conclusion This study indicated that lncRNAs are differentially expressed in early AMD and may produce important regulative effects. An lncRNA, RP11-234O6.2, might be involved in the biological regulation of early AMD and have therapeutic potential.
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Affiliation(s)
- Wei Zhu
- Department of Ophthalmology, Changshu No. 2 People's Hospital, Changshu, China
| | - Yi-Fang Meng
- Department of Ophthalmology, Changshu No. 2 People's Hospital, Changshu, China
| | - Qian Xing
- Department of Ophthalmology, Changshu No. 2 People's Hospital, Changshu, China
| | - Jian-Jun Tao
- Department of Ophthalmology, Changshu No. 2 People's Hospital, Changshu, China
| | - Jiong Lu
- Department of Ophthalmology, Changshu No. 2 People's Hospital, Changshu, China
| | - Yan Wu
- Department of Ophthalmology, First Hospital Affiliated to Soochow University, Suzhou, China
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15
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Benedetto MM, Guido ME, Contin MA. Non-Visual Photopigments Effects of Constant Light-Emitting Diode Light Exposure on the Inner Retina of Wistar Rats. Front Neurol 2017; 8:417. [PMID: 28871236 PMCID: PMC5566984 DOI: 10.3389/fneur.2017.00417] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022] Open
Abstract
The retina is part of the central nervous system specially adapted to capture light photons and transmit this information to the brain through photosensitive retinal cells involved in visual and non-visual activities. However, excessive light exposure may accelerate genetic retinal diseases or induce photoreceptor cell (PRC) death, finally leading to retinal degeneration (RD). Light pollution (LP) caused by the characteristic use of artificial light in modern day life may accelerate degenerative diseases or promote RD and circadian desynchrony. We have developed a working model to study RD mechanisms in a low light environment using light-emitting diode (LED) sources, at constant or long exposure times under LP conditions. The mechanism of PRC death is still not fully understood. Our main goal is to study the biochemical mechanisms of RD. We have previously demonstrated that constant light (LL) exposure to white LED produces a significant reduction in the outer nuclear layer (ONL) by classical PRC death after 7 days of LL exposure. The PRCs showed TUNEL-positive labeling and a caspase-3-independent mechanism of cell death. Here, we investigate whether constant LED exposure affects the inner-retinal organization and structure, cell survival and the expression of photopigments; in particular we look into whether constant LED exposure causes the death of retinal ganglion cells (RGCs), of intrinsically photosensitive RGCs (ipRGCs), or of other inner-retinal cells. Wistar rats exposed to 200 lx of LED for 2 to 8 days (LL 2 and LL 8) were processed for histological and protein. The results show no differences in the number of nucleus or TUNEL positive RGCs nor inner structural damage in any of LL groups studied, indicating that LL exposure affects ONL but does not produce RGC death. However, the photopigments melanopsin (OPN4) and neuropsin (OPN5) expressed in the inner retina were seen to modify their localization and expression during LL exposure. Our findings suggest that constant light during several days produces retinal remodeling and ONL cell death as well as significant changes in opsin expression in the inner nuclear layer.
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Affiliation(s)
- María M Benedetto
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mario E Guido
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María A Contin
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
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16
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Wu J, Ke X, Fu W, Gao X, Zhang H, Wang W, Ma N, Zhao M, Hao X, Zhang Z. Inhibition of Hypoxia-Induced Retinal Angiogenesis by Specnuezhenide, an Effective Constituent of Ligustrum lucidum Ait., through Suppression of the HIF-1α/VEGF Signaling Pathway. Molecules 2016; 21:molecules21121756. [PMID: 28009852 PMCID: PMC6272965 DOI: 10.3390/molecules21121756] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/10/2016] [Accepted: 12/17/2016] [Indexed: 11/30/2022] Open
Abstract
Specnuezhenide (SPN), one of the main ingredients of Chinese medicine “Nü-zhen-zi”, has anti-angiogenic and vision improvement effects. However, studies of its effect on retinal neovascularization are limited so far. In the present study, we established a vascular endothelial growth factor A (VEGFA) secretion model of human acute retinal pigment epithelial-19 (ARPE-19) cells by exposure of 150 μM CoCl2 to the cells and determined the VEGFA concentrations, the mRNA expressions of VEGFA, hypoxia inducible factor-1α (HIF-1α) & prolyl hydroxylases 2 (PHD-2), and the protein expressions of HIF-1α and PHD-2 after treatment of 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1, 1.0 μg/mL) or SPN (0.2, 1.0 and 5.0 μg/mL). Furthermore, rat pups with retinopathy were treated with SPN (5.0 and 10.0 mg/kg) in an 80% oxygen atmosphere and the retinal avascular areas were assessed through visualization using infusion of ADPase and H&E stains. The results showed that SPN inhibited VEGFA secretion by ARPE-19 cells under hypoxia condition, down-regulated the mRNA expressions of VEGFA and PHD-2 slightly, and the protein expressions of VEGFA, HIF-1α and PHD-2 significantly in vitro. SPN also prevented hypoxia-induced retinal neovascularization in a rat model of oxygen-induced retinopathy in vivo. These results indicate that SPN ameliorates retinal neovascularization through inhibition of HIF-1α/VEGF signaling pathway. Therefore, SPN has the potential to be developed as an agent for the prevention and treatment of diabetic retinopathy.
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Affiliation(s)
- Jianming Wu
- Laboratory of Chinese Materia Medica, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, Sichuan, China.
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
- Post-Doctoral Mobile Station, West China School of Pharmacy, Sichuan University, Chengdu 610041, Sichuan, China.
| | - Xiao Ke
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Wei Fu
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Xiaoping Gao
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Hongcheng Zhang
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Wei Wang
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Na Ma
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Manxi Zhao
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Xiaofeng Hao
- Post-Doctoral Research Station, KangHong Pharmaceutical Group, Chengdu 610036, Sichuan, China.
| | - Zhirong Zhang
- Post-Doctoral Mobile Station, West China School of Pharmacy, Sichuan University, Chengdu 610041, Sichuan, China.
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