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Bongiorni S, Catalani E, Arisi I, Lazzarini F, Del Quondam S, Brunetti K, Cervia D, Prantera G. Pathological Defects in a Drosophila Model of Alzheimer's Disease and Beneficial Effects of the Natural Product Lisosan G. Biomolecules 2024; 14:855. [PMID: 39062569 PMCID: PMC11274821 DOI: 10.3390/biom14070855] [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: 05/27/2024] [Revised: 07/09/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
Alzheimer's disease (AD) brains are histologically marked by the presence of intracellular and extracellular amyloid deposits, which characterize the onset of the disease pathogenesis. Increasing evidence suggests that certain nutrients exert a direct or indirect effect on amyloid β (Aβ)-peptide production and accumulation and, consequently, on AD pathogenesis. We exploited the fruit fly Drosophila melanogaster model of AD to evaluate in vivo the beneficial properties of Lisosan G, a fermented powder obtained from organic whole grains, on the intracellular Aβ-42 peptide accumulation and related pathological phenotypes of AD. Our data showed that the Lisosan G-enriched diet attenuates the production of neurotoxic Aβ peptides in fly brains and reduces neuronal apoptosis. Notably, Lisosan G exerted anti-oxidant effects, lowering brain levels of reactive oxygen species and enhancing mitochondrial activity. These aspects paralleled the increase in autophagy turnover and the inhibition of nucleolar stress. Our results give support to the use of the Drosophila model not only to investigate the molecular genetic bases of neurodegenerative disease but also to rapidly and reliably test the efficiency of potential therapeutic agents and diet regimens.
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Affiliation(s)
- Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, 01100 Viterbo, Italy; (S.B.); (F.L.); (G.P.)
| | - Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy; (E.C.); (S.D.Q.); (K.B.)
| | - Ivan Arisi
- Bioinformatics Facility, European Brain Research Institute (EBRI) “Rita Levi-Montalcini”, 00161 Rome, Italy;
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), 00133 Rome, Italy
| | - Francesca Lazzarini
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, 01100 Viterbo, Italy; (S.B.); (F.L.); (G.P.)
| | - Simona Del Quondam
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy; (E.C.); (S.D.Q.); (K.B.)
| | - Kashi Brunetti
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy; (E.C.); (S.D.Q.); (K.B.)
| | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy; (E.C.); (S.D.Q.); (K.B.)
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, 01100 Viterbo, Italy; (S.B.); (F.L.); (G.P.)
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2
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Szeto SK, Lai TY, Vujosevic S, Sun JK, Sadda SR, Tan G, Sivaprasad S, Wong TY, Cheung CY. Optical coherence tomography in the management of diabetic macular oedema. Prog Retin Eye Res 2024; 98:101220. [PMID: 37944588 DOI: 10.1016/j.preteyeres.2023.101220] [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: 06/28/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023]
Abstract
Diabetic macular oedema (DMO) is the major cause of visual impairment in people with diabetes. Optical coherence tomography (OCT) is now the most widely used modality to assess presence and severity of DMO. DMO is currently broadly classified based on the involvement to the central 1 mm of the macula into non-centre or centre involved DMO (CI-DMO) and DMO can occur with or without visual acuity (VA) loss. This classification forms the basis of management strategies of DMO. Despite years of research on quantitative and qualitative DMO related features assessed by OCT, these do not fully inform physicians of the prognosis and severity of DMO relative to visual function. Having said that, recent research on novel OCT biomarkers development and re-defined classification of DMO show better correlation with visual function and treatment response. This review summarises the current evidence of the association of OCT biomarkers in DMO management and its potential clinical importance in predicting VA and anatomical treatment response. The review also discusses some future directions in this field, such as the use of artificial intelligence to quantify and monitor OCT biomarkers and retinal fluid and identify phenotypes of DMO, and the need for standardisation and classification of OCT biomarkers to use in future clinical trials and clinical practice settings as prognostic markers and secondary treatment outcome measures in the management of DMO.
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Affiliation(s)
- Simon Kh Szeto
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Timothy Yy Lai
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Stela Vujosevic
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy; Eye Clinic, IRCCS MultiMedica, Milan, Italy
| | - Jennifer K Sun
- Beetham Eye Institute, Harvard Medical School, Boston, USA
| | - SriniVas R Sadda
- Doheny Eye Institute, University of California Los Angeles, Los Angeles, USA
| | - Gavin Tan
- Singapore Eye Research Institute, SingHealth Duke-National University of Singapore, Singapore
| | - Sobha Sivaprasad
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Tien Y Wong
- Tsinghua Medicine, Tsinghua University, Beijing, China; Singapore Eye Research Institute, Singapore
| | - Carol Y Cheung
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
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3
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Kour V, Swain J, Singh J, Singh H, Kour H. A Review on Diabetic Retinopathy. Curr Diabetes Rev 2024; 20:e201023222418. [PMID: 37867267 DOI: 10.2174/0115733998253672231011161400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/08/2023] [Accepted: 08/23/2023] [Indexed: 10/24/2023]
Abstract
Diabetic retinopathy is a well-recognised microvascular complication of diabetes and is among the leading cause of blindness all over the world. Over the last decade, there have been advances in the diagnosis of diabetic retinopathy and diabetic macular edema. At the same time, newer therapies for the management of diabetic retinopathy have evolved. As a result of these advances, a decline in severe vision loss due to diabetes has been witnessed in some developing countries. However, there is a steady increase in the number of people affected with diabetes, and is expected to rise further in the coming years. Therefore, it is prudent to identify diabetic retinopathy, and timely intervention is needed to decrease the burden of severe vision loss. An effort has been made to review all the existing knowledge regarding diabetic retinopathy in this article and summarize the present treatment options for diabetic retinopathy.
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Affiliation(s)
- Vijender Kour
- Consultant Ophthalmology, Department of Ophthalmology, Sub District Hospital, Tral, Pulwama, India
| | - Jayshree Swain
- Department of Endocrinology, IMS and Sum Hospital, Siksha O Anusandhan (SOA) University, Bhubaneswar, India
| | - Jaspreet Singh
- Department of Endocrinology, IMS and Sum Hospital, Siksha O Anusandhan (SOA) University, Bhubaneswar, India
| | - Hershdeep Singh
- Consultant Neurosurgeon, Department of Neurosurgery, Fortis Ludhiana, Bhubaneswar, India
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4
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Catalani E, Del Quondam S, Brunetti K, Cherubini A, Bongiorni S, Taddei AR, Zecchini S, Giovarelli M, De Palma C, Perrotta C, Clementi E, Prantera G, Cervia D. Neuroprotective role of plumbagin on eye damage induced by high-sucrose diet in adult fruit fly Drosophila melanogaster. Biomed Pharmacother 2023; 166:115298. [PMID: 37597318 DOI: 10.1016/j.biopha.2023.115298] [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: 06/23/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 08/21/2023] Open
Abstract
The natural compound plumbagin has a wide range of pharmacological and potential therapeutic activities, although its role in neuroretina degeneration is unknown. Here we evaluated the effects of plumbagin on retina homeostasis of the fruit fly Drosophila melanogaster fed with high glucose diet, a model of hyperglycemia-induced eye impairment to study the pathophysiology of diabetic retinopathy at the early stages. To this aim, the visual system of flies orally administered with plumbagin has been analyzed at structural, functional, and molecular/cellular level as for instance neuronal apoptosis/autophagy dysregulation and oxidative stress-related signals. Our results demonstrated that plumbagin ameliorates the visual performance of hyperglycemic flies. Drosophila eye-structure, clearly altered by hyperglycemia, i.e. defects of the pattern of ommatidia, irregular rhabdomeres, vacuoles, damaged mitochondria, and abnormal phototransduction units were rescued, at least in part, by plumbagin. In addition, it reactivated autophagy, decreased the presence of cell death/apoptotic features, and exerted antioxidant effects in the retina. In terms of mechanisms favoring death/survival ratio, Nrf2 signaling activation may be one of the strategies by which plumbagin reduced redox unbalance mainly increasing the levels of glutathione-S-transferase. Likewise, plumbagin may act additively and/or synergistically inhibiting the mitochondrial-endoplasmic reticulum stress and unfolded protein response pathways, which prevented neuronal impairment and eye damage induced by reactive oxygen species. These results provide an avenue for further studies, which may be helpful to develop novel therapeutic candidates and drug targets against eye neurotoxicity by high glucose, a key aspect in retinal complications of diabetes.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Simona Del Quondam
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Kashi Brunetti
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Agnese Cherubini
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Zecchini
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Matteo Giovarelli
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via L. Vanvitelli 32, 20129 Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Emilio Clementi
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy; Scientific Institute IRCCS "Eugenio Medea", via Don Luigi Monza 20, 23842 Bosisio Parini, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy.
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5
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Du Y, Yan B. Ocular immune privilege and retinal pigment epithelial cells. J Leukoc Biol 2023; 113:288-304. [PMID: 36805720 DOI: 10.1093/jleuko/qiac016] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Indexed: 02/04/2023] Open
Abstract
The ocular tissue microenvironment is immune-privileged and uses multiple immunosuppressive mechanisms to prevent the induction of inflammation. The retinal pigment epithelium plays an essential role in ocular immune privilege. In addition to serving as a blood barrier separating the fenestrated choriocapillaris from the retina, the retinal pigment epithelium is a source of immunosuppressive cytokines and membrane-bound negative regulators that modulate the activity of immune cells within the retina. This article reviews the current understanding of how retinal pigment epithelium cells mediate immune regulation, focusing on the changes under pathologic conditions.
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Affiliation(s)
- Yuxiang Du
- Institute of Precision Medicine, Jining Medical University, No. 133, Hehua Road, Taibaihu New District, Jining, Shandong 272067, People's Republic of China
| | - Bo Yan
- Institute of Precision Medicine, Jining Medical University, No. 133, Hehua Road, Taibaihu New District, Jining, Shandong 272067, People's Republic of China
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6
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Antropoli A, Arrigo A, La Franca L, Bianco L, Barlocci E, Fusi E, Bandello F, Battaglia Parodi M. Peripheral and central capillary non-perfusion in diabetic retinopathy: An updated overview. Front Med (Lausanne) 2023; 10:1125062. [PMID: 37035306 PMCID: PMC10076599 DOI: 10.3389/fmed.2023.1125062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
Capillary non-perfusion (CNP) is one of the key hallmarks of diabetic retinopathy (DR), which may develop both in the periphery and at the posterior pole. Our perspectives on CNP have extended with the introduction of optical coherence tomography angiography (OCTA) and ultra-widefield imaging, and the clinical consequences of peripheral and macular CNP have been well characterized. Fluorescein angiography (FA) continues to be the gold standard for detecting and measuring CNP, particularly when ultra-widefield imaging is available. OCTA, on the other hand, is a quicker, non-invasive approach that allows for a three-dimensional examination of CNP and may soon be regarded as an useful alternative to FA. In this review, we provide an updated scenario regarding the characteristics, clinical impact, and management of central and peripheral CNP in DR.
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7
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Amato R, Catalani E, Dal Monte M, Cammalleri M, Cervia D, Casini G. Morpho-functional analysis of the early changes induced in retinal ganglion cells by the onset of diabetic retinopathy: The effects of a neuroprotective strategy. Pharmacol Res 2022; 185:106516. [DOI: 10.1016/j.phrs.2022.106516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/05/2022] [Accepted: 10/14/2022] [Indexed: 10/31/2022]
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8
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Cheung CMG, Fawzi A, Teo KY, Fukuyama H, Sen S, Tsai WS, Sivaprasad S. Diabetic macular ischaemia- a new therapeutic target? Prog Retin Eye Res 2022; 89:101033. [PMID: 34902545 PMCID: PMC11268431 DOI: 10.1016/j.preteyeres.2021.101033] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/25/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022]
Abstract
Diabetic macular ischaemia (DMI) is traditionally defined and graded based on the angiographic evidence of an enlarged and irregular foveal avascular zone. However, these anatomical changes are not surrogate markers for visual impairment. We postulate that there are vascular phenotypes of DMI based on the relative perfusion deficits of various retinal capillary plexuses and choriocapillaris. This review highlights several mechanistic pathways, including the role of hypoxia and the complex relation between neurons, glia, and microvasculature. The current animal models are reviewed, with shortcomings noted. Therefore, utilising the advancing technology of optical coherence tomography angiography (OCTA) to identify the reversible DMI phenotypes may be the key to successful therapeutic interventions for DMI. However, there is a need to standardise the nomenclature of OCTA perfusion status. Visual acuity is not an ideal endpoint for DMI clinical trials. New trial endpoints that represent disease progression need to be developed before irreversible vision loss in patients with DMI. Natural history studies are required to determine the course of each vascular and neuronal parameter to define the DMI phenotypes. These DMI phenotypes may also partly explain the development and recurrence of diabetic macular oedema. It is also currently unclear where and how DMI fits into the diabetic retinopathy severity scales, further highlighting the need to better define the progression of diabetic retinopathy and DMI based on both multimodal imaging and visual function. Finally, we discuss a complete set of proposed therapeutic pathways for DMI, including cell-based therapies that may provide restorative potential.
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Affiliation(s)
- Chui Ming Gemmy Cheung
- Singapore Eye Research Institution, Singapore National Eye Centre, Singapore; Duke-NUS Medical School, National University of Singapore, Singapore
| | | | - Kelvin Yc Teo
- Singapore Eye Research Institution, Singapore National Eye Centre, Singapore
| | | | | | - Wei-Shan Tsai
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, United Kingdom
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, United Kingdom.
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9
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Pöstyéni E, Ganczer A, Kovács-Valasek A, Gabriel R. Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice. Front Pharmacol 2022; 12:808315. [PMID: 35095518 PMCID: PMC8793341 DOI: 10.3389/fphar.2021.808315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian retina contains approximately 30 neuropeptides that are synthetized by different neuronal cell populations, glia, and the pigmented epithelium. The presence of these neuropeptides leaves a mark on normal retinal molecular processes and physiology, and they are also crucial in fighting various pathologies (e.g., diabetic retinopathy, ischemia, age-related pathologies, glaucoma) because of their protective abilities. Retinal pathologies of different origin (metabolic, genetic) are extensively investigated by genetically manipulated in vivo mouse models that help us gain a better understanding of the molecular background of these pathomechanisms. These models offer opportunities to manipulate gene expression in different cell types to help reveal their roles in the preservation of retinal health or identify malfunction during diseases. In order to assess the current status of transgenic technologies available, we have conducted a literature survey focused on retinal disorders of metabolic origin, zooming in on the role of retinal neuropeptides in diabetic retinopathy and ischemia. First, we identified those neuropeptides that are most relevant to retinal pathologies in humans and the two clinically most relevant models, mice and rats. Then we continued our analysis with metabolic disorders, examining neuropeptide-related pathways leading to systemic or cellular damage and rescue. Last but not least, we reviewed the available literature on genetically modified mouse strains to understand how the manipulation of a single element of any given pathway (e.g., signal molecules, receptors, intracellular signaling pathways) could lead either to the worsening of disease conditions or, more frequently, to substantial improvements in retinal health. Most attention was given to studies which reported successful intervention against specific disorders. For these experiments, a detailed evaluation will be given and the possible role of converging intracellular pathways will be discussed. Using these converging intracellular pathways, curative effects of peptides could potentially be utilized in fighting metabolic retinal disorders.
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Affiliation(s)
- Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Alma Ganczer
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
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10
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Nutraceutical Strategy to Counteract Eye Neurodegeneration and Oxidative Stress in Drosophila melanogaster Fed with High-Sugar Diet. Antioxidants (Basel) 2021; 10:antiox10081197. [PMID: 34439445 PMCID: PMC8388935 DOI: 10.3390/antiox10081197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 12/14/2022] Open
Abstract
Aberrant production of reactive oxygen species (ROS) is a common feature of damaged retinal neurons in diabetic retinopathy, and antioxidants may exert both preventive and therapeutic action. To evaluate the beneficial and antioxidant properties of food supplementation with Lisosan G, a powder of bran and germ of grain (Triticum aestivum) obtained by fermentation with selected lactobacillus and natural yeast strains, we used an in vivo model of hyperglycemia-induced retinal damage, the fruit fly Drosophila melanogaster fed with high-sucrose diet. Lisosan G positively affected the visual system of hyperglycemic flies at structural/functional level, decreased apoptosis, and reactivated protective autophagy at the retina internal network. Also, in high sucrose-fed Drosophila, Lisosan G reduced the levels of brain ROS and retina peroxynitrite. The analysis of oxidative stress-related metabolites suggested 7,8-dihydrofolate, uric acid, dihydroorotate, γ-L-glutamyl-L-cysteine, allantoin, cysteinyl-glycine, and quinolate as key mediators of Lisosan G-induced inhibition of neuronal ROS, along with the upregulation of glutathione system. Of note, Lisosan G may impact oxidative stress and the ensuing retinal cell death, also independently from autophagy, although the autophagy-ROS cross-talk is critical. This study demonstrated that the continuous supplementation with the alimentary integrator Lisosan G exerts a robust and multifaceted antioxidant effect on retinal neurons, thus providing efficacious neuroprotection of hyperglycemic eye.
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11
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Catalani E, Silvestri F, Bongiorni S, Taddei AR, Fanelli G, Rinalducci S, De Palma C, Perrotta C, Prantera G, Cervia D. Retinal damage in a new model of hyperglycemia induced by high-sucrose diets. Pharmacol Res 2021; 166:105488. [PMID: 33582248 DOI: 10.1016/j.phrs.2021.105488] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/13/2022]
Abstract
Loss of retinal neurons may precede clinical signs of diabetic retinopathy (DR). We studied for the first time the effects of hyperglycemia on the visual system of the fruit fly Drosophila melanogaster to characterize a model for glucose-induced retinal neurodegeneration, thus complementing more traditional vertebrate systems. Adult flies were fed with increased high-sucrose regimens which did not modify the locomotion ability, muscle phenotype and mobility after 10 days. The increased availability of dietary sucrose induced hyperglycemia and phosphorylation of Akt in fat tissue, without significant effects on adult growth and viability, consistent with the early phase of insulin signaling and a low impact on the overall metabolic profile of flies at short term. Noteworthy, high-sucrose diets significantly decreased Drosophila responsiveness to the light as a consequence of vision defects. Hyperglycemia did not alter the gross anatomical architecture of the external eye phenotype although a progressive damage of photosensitive units was observed. Appreciable levels of cleaved caspase 3 and nitrotyrosine were detected in the internal retina network as well as punctate staining of Light-Chain 3 and p62, and accumulated autophagosomes, indicating apoptotic features, peroxynitrite formation and autophagy turnover defects. In summary, our results in Drosophila support the view that hyperglycemia induced by high-sucrose diets lead to eye defects, apoptosis/autophagy dysregulation, oxidative stress, and visual dysfunctions which are evolutionarily conserved, thus offering a meaningful opportunity of using a simple in vivo model to study the pathophysiology of neuroretinal alterations that develop in patients at the early stages of DR.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Federica Silvestri
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Giuseppina Fanelli
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Sara Rinalducci
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via L. Vanvitelli 32, 20129 Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy.
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12
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Catalani E, Bongiorni S, Taddei AR, Mezzetti M, Silvestri F, Coazzoli M, Zecchini S, Giovarelli M, Perrotta C, De Palma C, Clementi E, Ceci M, Prantera G, Cervia D. Defects of full-length dystrophin trigger retinal neuron damage and synapse alterations by disrupting functional autophagy. Cell Mol Life Sci 2020; 78:1615-1636. [PMID: 32749504 PMCID: PMC7904721 DOI: 10.1007/s00018-020-03598-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/10/2020] [Accepted: 07/09/2020] [Indexed: 02/06/2023]
Abstract
Dystrophin (dys) mutations predispose Duchenne muscular disease (DMD) patients to brain and retinal complications. Although different dys variants, including long dys products, are expressed in the retina, their function is largely unknown. We investigated the putative role of full-length dystrophin in the homeostasis of neuro-retina and its impact on synapsis stabilization and cell fate. Retinas of mdx mice, the most used DMD model which does not express the 427-KDa dys protein (Dp427), showed overlapped cell death and impaired autophagy. Apoptotic neurons in the outer plexiform/inner nuclear layer and the ganglion cell layer had an impaired autophagy with accumulated autophagosomes. The autophagy dysfunction localized at photoreceptor axonal terminals and bipolar, amacrine, and ganglion cells. The absence of Dp427 does not cause a severe phenotype but alters the neuronal architecture, compromising mainly the pre-synaptic photoreceptor terminals and their post-synaptic sites. The analysis of two dystrophic mutants of the fruit fly Drosophila melanogaster, the homozygous DysE17 and DysEP3397, lacking functional large-isoforms of dystrophin-like protein, revealed rhabdomere degeneration. Structural damages were evident in the internal network of retina/lamina where photoreceptors make the first synapse. Both accumulated autophagosomes and apoptotic features were detected and the visual system was functionally impaired. The reactivation of the autophagosome turnover by rapamycin prevented neuronal cell death and structural changes of mutant flies and, of interest, sustained autophagy ameliorated their response to light. Overall, these findings indicate that functional full-length dystrophin is required for synapsis stabilization and neuronal survival of the retina, allowing also proper autophagy as a prerequisite for physiological cell fate and visual properties.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Marta Mezzetti
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Federica Silvestri
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Marco Coazzoli
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Silvia Zecchini
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Matteo Giovarelli
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via Luigi Vanvitelli 32, 20129 , Milano, Italy
| | - Emilio Clementi
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
- Unit of Clinical Pharmacology, University Hospital "Luigi Sacco"-ASST Fatebenefratelli Sacco, via G.B. Grassi 74, 20157, Milano, Italy
- Scientific Institute IRCCS "Eugenio Medea", via Don Luigi Monza 20, 23842, Bosisio Parini (LC), Italy
| | - Marcello Ceci
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy.
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy.
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Rossino MG, Lulli M, Amato R, Cammalleri M, Dal Monte M, Casini G. Oxidative Stress Induces a VEGF Autocrine Loop in the Retina: Relevance for Diabetic Retinopathy. Cells 2020; 9:E1452. [PMID: 32545222 PMCID: PMC7349409 DOI: 10.3390/cells9061452] [Citation(s) in RCA: 24] [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: 05/10/2020] [Revised: 06/01/2020] [Accepted: 06/10/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Oxidative stress (OS) plays a central role in diabetic retinopathy (DR), triggering expression and release of vascular endothelial growth factor (VEGF), the increase of which leads to deleterious vascular changes. We tested the hypothesis that OS-stimulated VEGF induces its own expression with an autocrine mechanism. METHODS MIO-M1 cells and ex vivo mouse retinal explants were treated with OS, with exogenous VEGF or with conditioned media (CM) from OS-stressed cultures. RESULTS Both in MIO-M1 cells and in retinal explants, OS or exogenous VEGF induced a significant increase of VEGF mRNA, which was abolished by VEGF receptor 2 (VEGFR-2) inhibition. OS also caused VEGF release. In MIO-M1 cells, CM induced VEGF expression, which was abolished by a VEGFR-2 inhibitor. Moreover, the OS-induced increase of VEGF mRNA was abolished by a nuclear factor erythroid 2-related factor 2 (Nrf2) blocker, while the effect of exo-VEGF resulted Nrf2-independent. Finally, both the exo-VEGF- and the OS-induced increase of VEGF expression were blocked by a hypoxia-inducible factor-1 inhibitor. CONCLUSIONS These results are consistent with the existence of a retinal VEGF autocrine loop triggered by OS. This mechanism may significantly contribute to the maintenance of elevated VEGF levels and therefore it may be of central importance for the onset and development of DR.
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Affiliation(s)
- Maria Grazia Rossino
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
| | - Matteo Lulli
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy;
| | - Rosario Amato
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
| | - Maurizio Cammalleri
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Giovanni Casini
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
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Yue J, Zhao X. GPR174 suppression attenuates retinopathy in angiotensin II (Ang II)-treated mice by reducing inflammation via PI3K/AKT signaling. Biomed Pharmacother 2019; 122:109701. [PMID: 31918274 DOI: 10.1016/j.biopha.2019.109701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/12/2019] [Accepted: 11/24/2019] [Indexed: 02/07/2023] Open
Abstract
Hypertension is closely associated with eye diseases, including hypertensive retinopathy. However, the molecular mechanism controlling the progression of hypertensive retinopathy remains poorly understood. G-Protein Coupled Receptor 174 (GPR174) is expressed in various tissues, and plays a critical role in regulating immune and inflammatory responses. However, if GPR174 is involved in angiotensin II (Ang II)-induced retinopathy is still unclear. In this study, hypertensive retinopathy was induced by Ang II infusion in the wild type (GPR174+/+) and GPR174 knockout (GPR174-/-) mice. Clinical data indicated that GPR174 levels were markedly up-regulated in serum of patients with hypertension (HP) or hypertensive retinopathy (HR), along with increased trypsin-like activity. Similar changes of GRP174 and trypsin-like activity were observed in Ang II-infused mice. Furthermore, Ang IIsignificantly increased the central retinal thickness, vascular permeability and inflammatory response in GPR174+/+ micewhen compared with the saline GPR174+/+ mice. Of note, these effects were markedly alleviated by the knockout ofGPR174 in Ang II-treated mice. Consistently, vascular endothelial growth factor (VEGF) expression levels in retinal tissue were also stimulated by Ang II, which were clearly attenuated by GPR174-/-. In addition, phosphatidylinositol 3-kinase (PI3 K)/AKT and nuclear factor-κB (NF-κB) signaling pathways were markedly activated in retinas of Ang II-infused GPR174+/+ mice, whereas being greatly ameliorated by GPR174-/-. The in vitro data showed that pre-treatment of PI3 K/AKT specific inhibitor LY294002 remarkably abrogated GPR174 over-expression-accelerated expression levels of Iba-1, tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in lipopolysaccharide (LPS)-incubated retinal microglial cells.Furthermore, in LPS-exposed retinal microglial cells, PI3 K/AKT and NF-κB pathways were further promoted by GPR174 over-expression, which were significantlyabolished by LY294002. Thus, GPR174 might be a positive meditator of inflammation, contributing to Ang II-induced retinopathy by activating PI3 K/AKT signaling, and could be considered as a novel therapeutic target for the treatment of hypertensive retinopathy.
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Affiliation(s)
- Jianzhong Yue
- Department of Ophthalmology, Hanzhong City Central Hospital, Hanzhong City, Shaanxi Province, 723000, China
| | - Xin Zhao
- Department of Faculty of Medicine, Weinan Vocational and Technical College, Weinan City, Shaanxi Province, 714026, China.
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15
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Rossino MG, Dal Monte M, Casini G. Relationships Between Neurodegeneration and Vascular Damage in Diabetic Retinopathy. Front Neurosci 2019; 13:1172. [PMID: 31787868 PMCID: PMC6856056 DOI: 10.3389/fnins.2019.01172] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/16/2019] [Indexed: 12/15/2022] Open
Abstract
Diabetic retinopathy (DR) is a common complication of diabetes and constitutes a major cause of vision impairment and blindness in the world. DR has long been described exclusively as a microvascular disease of the eye. However, in recent years, a growing interest has been focused on the contribution of neuroretinal degeneration to the pathogenesis of the disease, and there are observations suggesting that neuronal death in the early phases of DR may favor the development of microvascular abnormalities, followed by the full manifestation of the disease. However, the mediators that are involved in the crosslink between neurodegeneration and vascular changes have not yet been identified. According to our hypothesis, vascular endothelial growth factor (VEGF) could probably be the most important connecting link between the death of retinal neurons and the occurrence of microvascular lesions. Indeed, VEGF is known to play important neuroprotective actions; therefore, in the early phases of DR, it may be released in response to neuronal suffering, and it would act as a double-edged weapon inducing both neuroprotective and vasoactive effects. If this hypothesis is correct, then any retinal stress causing neuronal damage should be accompanied by VEGF upregulation and by vascular changes. Similarly, any compound with neuroprotective properties should also induce VEGF downregulation and amelioration of the vascular lesions. In this review, we searched for a correlation between neurodegeneration and vasculopathy in animal models of retinal diseases, examining the effects of different neuroprotective substances, ranging from nutraceuticals to antioxidants to neuropeptides and others and showing that reducing neuronal suffering also prevents overexpression of VEGF and vascular complications. Taken together, the reviewed evidence highlights the crucial role played by mediators such as VEGF in the relationship between retinal neuronal damage and vascular alterations and suggests that the use of neuroprotective substances could be an efficient strategy to prevent the onset or to retard the development of DR.
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Affiliation(s)
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | - Giovanni Casini
- Department of Biology, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
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16
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Kovacs K, Vaczy A, Fekete K, Kovari P, Atlasz T, Reglodi D, Gabriel R, Gallyas F, Sumegi B. PARP Inhibitor Protects Against Chronic Hypoxia/Reoxygenation-Induced Retinal Injury by Regulation of MAPKs, HIF1α, Nrf2, and NFκB. Invest Ophthalmol Vis Sci 2019; 60:1478-1490. [PMID: 30973576 DOI: 10.1167/iovs.18-25936] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose In the eye, chronic hypoxia/reoxygenation (H/R) contributes to the development of a number of ocular disorders. H/R induces the production of reactive oxygen species (ROS), leading to poly(ADP-ribose) polymerase-1 (PARP1) activation that promotes inflammation, cell death, and disease progression. Here, we analyzed the protective effects of the PARP1 inhibitor olaparib in H/R-induced retina injury and investigated the signaling mechanisms involved. Methods A rat retinal H/R model was used to detect histologic and biochemical changes in the retina. Results H/R induced reductions in the thickness of most retinal layers, which were prevented by olaparib. Furthermore, H/R caused increased levels of Akt and glycogen synthase kinase-3β phosphorylation, which were further increased by olaparib, contributing to retina protection. By contrast, H/R-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinases (MAPK) phosphorylation and activation were reduced by olaparib, via mitogen-activated protein kinase phosphatase 1 (MKP-1) expression. In addition, H/R-induced hypoxia-inducible factor 1α (HIF1α) levels were decreased by olaparib, which possibly contributed to reduced VEGF expression. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression was slightly increased by H/R and was further activated by olaparib. Nuclear factor-κB (NFκB) was also activated by H/R through phosphorylation (Ser536) and acetylation (Lys310) of the p65 subunit, although this was significantly reduced by olaparib. Conclusions Olaparib reduced H/R-induced degenerative changes in retinal morphology. The protective mechanisms of olaparib most probably involved Nrf2 activation and ROS reduction, as well as normalization of HIF1α and related VEGF expression. In addition, olaparib reduced inflammation by NFκB dephosphorylation/inactivation, possibly via the PARP1 inhibition-MKP-1 activation-p38 MAPK inhibition pathway. PARP inhibitors represent potential therapeutics in H/R-induced retinal disease.
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Affiliation(s)
- Krisztina Kovacs
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Pécs, Hungary
| | - Alexandra Vaczy
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pécs Medical School, Pécs, Hungary
| | - Katalin Fekete
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Pécs, Hungary
| | - Petra Kovari
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pécs Medical School, Pécs, Hungary
| | - Tamas Atlasz
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pécs Medical School, Pécs, Hungary.,Department of Sportbiology, Faculty of Sciences, University of Pécs, Pécs, Hungary.,Szentagothai Research Centre, University of Pécs, Pécs, Hungary
| | - Dora Reglodi
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pécs Medical School, Pécs, Hungary
| | - Robert Gabriel
- Department of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary
| | - Ferenc Gallyas
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Pécs, Hungary.,Szentagothai Research Centre, University of Pécs, Pécs, Hungary.,Nuclear-Mitochondrial Interactions Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Balazs Sumegi
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Pécs, Hungary.,Szentagothai Research Centre, University of Pécs, Pécs, Hungary.,Nuclear-Mitochondrial Interactions Research Group, Hungarian Academy of Sciences, Budapest, Hungary
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17
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Neuroprotective Peptides in Retinal Disease. J Clin Med 2019; 8:jcm8081146. [PMID: 31374938 PMCID: PMC6722704 DOI: 10.3390/jcm8081146] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
In the pathogenesis of many disorders, neuronal death plays a key role. It is now assumed that neurodegeneration is caused by multiple and somewhat converging/overlapping death mechanisms, and that neurons are sensitive to unique death styles. In this respect, major advances in the knowledge of different types, mechanisms, and roles of neurodegeneration are crucial to restore the neuronal functions involved in neuroprotection. Several novel concepts have emerged recently, suggesting that the modulation of the neuropeptide system may provide an entirely new set of pharmacological approaches. Neuropeptides and their receptors are expressed widely in mammalian retinas, where they exert neuromodulatory functions including the processing of visual information. In multiple models of retinal diseases, different peptidergic substances play neuroprotective actions. Herein, we describe the novel advances on the protective roles of neuropeptides in the retina. In particular, we focus on the mechanisms by which peptides affect neuronal death/survival and the vascular lesions commonly associated with retinal neurodegenerative pathologies. The goal is to highlight the therapeutic potential of neuropeptide systems as neuroprotectants in retinal diseases.
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18
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Dysfunctional autophagy induced by the pro-apoptotic natural compound climacostol in tumour cells. Cell Death Dis 2018; 10:10. [PMID: 30584259 PMCID: PMC6315039 DOI: 10.1038/s41419-018-1254-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 11/06/2018] [Accepted: 12/03/2018] [Indexed: 01/22/2023]
Abstract
Autophagy occurs at a basal level in all eukaryotic cells and may support cell survival or activate death pathways. Due to its pathophysiologic significance, the autophagic machinery is a promising target for the development of multiple approaches for anti-neoplastic agents. We have recently described the cytotoxic and pro-apoptotic mechanisms, targeting the tumour suppressor p53, of climacostol, a natural product of the ciliated protozoan Climacostomum virens. We report here on how climacostol regulates autophagy and the involvement of p53-dependent mechanisms. Using both in vitro and in vivo techniques, we show that climacostol potently and selectively impairs autophagy in multiple tumour cells that are committed to die by apoptosis. In particular, in B16-F10 mouse melanomas climacostol exerts a marked and sustained accumulation of autophagosomes as the result of dysfunctional autophagic degradation. We also provide mechanistic insights showing that climacostol affects autophagosome turnover via p53-AMPK axis, although the mTOR pathway unrelated to p53 levels plays a role. In particular, climacostol activated p53 inducing the upregulation of p53 protein levels in the nuclei through effects on p53 stability at translational level, as for instance the phosphorylation at Ser15 site. Noteworthy, AMPKα activation was the major responsible of climacostol-induced autophagy disruption in the absence of a key role regulating cell death, thus indicating that climacostol effects on autophagy and apoptosis are two separate events, which may act independently on life/death decisions of the cell. Since the activation of p53 system is at the molecular crossroad regulating both the anti-autophagic action of climacostol and its role in the apoptosis induction, it might be important to explore the dual targeting of autophagy and apoptosis with agents acting on p53 for the selective killing of tumours. These findings also suggest the efficacy of ciliate bioactive molecules to identify novel lead compounds in drug discovery and development.
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Wang S, Ji LY, Li L, Li JM. Oxidative stress, autophagy and pyroptosis in the neovascularization of oxygen‑induced retinopathy in mice. Mol Med Rep 2018; 19:927-934. [PMID: 30569132 PMCID: PMC6323229 DOI: 10.3892/mmr.2018.9759] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 11/08/2018] [Indexed: 02/06/2023] Open
Abstract
Retinal neovascularization (RNV) is a principal cause of visual impairment and blindness worldwide. The present study aimed to investigate how oxidative stress, autophagy and pyroptosis alter in RNV. The oxygen‑induced retinopathy (OIR) model was established in C57BL/6J mice by exposing them to a high concentration of oxygen. RNV was clearly visible in the fundus images and was qualitatively analyzed by counting the number of neovascular endothelial cell nuclei at postnatal day 17. Subsequently, the expression of vascular endothelial growth factor (VEGF)‑A and hypoxia‑inducible factor‑1α (HIF‑1α) at the protein level were measured. Furthermore, oxidative stress was examined using dihydroethidium (DHE) staining, and NADPH oxidase (NOX) 1 and 4 in the retinas were detected using reverse transcription‑quantitative polymerase chain reaction analysis. Additionally, immunostaining of microtubule associated protein 1 light chain 3α (LC3) was performed and the expression levels of the LC3, p62, autophagy protein (Atg)5, Atg7, Atg12, Beclin1, NOD‑like receptor family pyrin domain‑containing 3 (NLRP3), caspase‑1, interleukin (IL)‑1β, pro‑caspase‑1 and pro‑IL‑1β proteins were determined using western blotting in order to detect pyroptosis and autophagic flux. Autophagosomes were also detected using transmission electron microscopy. The results revealed that VEGF‑A and HIF‑1α protein expression levels, the DHE‑positive area, and NOX1 and NOX4 mRNA expression levels were significantly increased in the OIR mice. Furthermore, increased levels of NLRP3, caspase‑1, IL‑1β, pro‑caspase‑1 and pro‑IL‑1β proteins demonstrated that pyroptosis was activated. However, an accumulation of p62 and a reduction in the levels of LC3II/I and autophagosomes indicated that autophagic flux was compromised. Therefore, elevated levels of reactive oxygen species and pyroptosis along with attenuated autophagy were demonstrated in the OIR mice. The combination of oxidative stress, pyroptosis and impaired autophagy may serve an important role in the pathophysiology of RNV and may be a potential target to prevent RNV.
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Affiliation(s)
- Shuai Wang
- Department of Ophthalmology, Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
| | - Li-Yang Ji
- Department of Ophthalmology, Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
| | - Li Li
- Department of Ophthalmology, Zaozhuang Municipal Hospital, Zaozhuang, Shandong 277000, P.R. China
| | - Jing-Min Li
- Department of Ophthalmology, Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
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20
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Wang S, Li J, Bai J, Li JM, Che YL, Lin QY, Zhang YL, Li HH. The immunoproteasome subunit LMP10 mediates angiotensin II-induced retinopathy in mice. Redox Biol 2018; 16:129-138. [PMID: 29499566 PMCID: PMC5952914 DOI: 10.1016/j.redox.2018.02.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 01/27/2023] Open
Abstract
Inflammation has been implicated in a variety of retinal diseases. The immunoproteasome plays a critical role in controlling inflammatory responses, but whether activation of immunoproteasome contributes to angiotensin II (Ang II)-induced retinopathy remains unclear. Hypertensive retinopathy (HR) was induced by infusion of Ang II (3000 ng/kg/min) in wild-type (WT) and immunoproteasome subunit LMP10 knockout (KO) mice for 3 weeks. Changes in retinal morphology, vascular permeability, superoxide production and inflammation were examined by pathological staining. Our results showed that immunoproteasome subunit LMP10 expression and its trypsin-like activity were significantly upregulated in the retinas and serum of Ang II-infused mice and in the serum from patients with hypertensive retinopathy. Moreover, Ang II-infused WT mice showed an increase in the central retinal thickness, vascular permeability, reactive oxygen species (ROS) production and inflammation compared with saline controls, and these effects were significantly attenuated in LMP10 KO mice, but were aggravated in mice intravitreally injected with rAAV2-LMP10. Interestingly, administration of IKKβ specific inhibitor IMD-0354 remarkably blocked an Ang II-induced increase in vascular permeability, oxidative stress and inflammation during retinopathy. Mechanistically, Ang II-induced upregulation of LMP10 promoted PTEN degradation and activation of AKT/IKK signaling, which induced IkBα phosphorylation and subsequent degradation ultimately leading to activation of NF-kB target genes in retinopathy. Therefore, this study provided novel evidence demonstrating that LMP10 is a positive regulator of NF-kB signaling, which contributes to Ang II-induced retinopathy. Strategies for inhibiting LMP10 or IKKβ activity in the eye could serve as a novel therapeutic target for treating hypertensive retinopathy.
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Affiliation(s)
- Shuai Wang
- Department of Ophthalmology, Second Affiliated Hospital of Dalian Medical University, Dalian 116023, China; School of Public Health, Dalian Medical University, Dalian 116004, China
| | - Jing Li
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian 11600, China
| | - Jie Bai
- School of Public Health, Dalian Medical University, Dalian 116004, China
| | - Jing-Min Li
- Department of Ophthalmology, Second Affiliated Hospital of Dalian Medical University, Dalian 116023, China
| | - Yi-Lin Che
- Department of Radiotherapy Oncology, Second Affiliated Hospital of Dalian Medical University, Dalian 116023, China
| | - Qiu-Yue Lin
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian 11600, China
| | - Yun-Long Zhang
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian 11600, China
| | - Hui-Hua Li
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian 11600, China; School of Public Health, Dalian Medical University, Dalian 116004, China.
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21
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Fewer Functional Deficits and Reduced Cell Death after Ranibizumab Treatment in a Retinal Ischemia Model. Int J Mol Sci 2018; 19:ijms19061636. [PMID: 29857531 PMCID: PMC6032266 DOI: 10.3390/ijms19061636] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 05/22/2018] [Indexed: 12/25/2022] Open
Abstract
Retinal ischemia is an important factor in several eye disorders. To investigate the impact of VEGF inhibitors, as a therapeutic option, we studied these in a retinal ischemia animal model. Therefore, animals received bevacizumab or ranibizumab intravitreally one day after ischemia induction. Via electroretinography, a significant decrease in a- and b-wave amplitudes was detected fourteen days after ischemia, but they were reduced to a lesser extent in the ranibizumab group. Ischemic and bevacizumab retinae displayed fewer retinal ganglion cells (RGCs), while no significant cell loss was noted in the ranibizumab group. Apoptosis was reduced after therapy. More autophagocytotic cells were observed in ischemic and bevacizumab eyes, but not in ranibizumab eyes. Additionally, more microglia, as well as active ones, were revealed in all ischemic groups, but the increase was less prominent under ranibizumab treatment. Fewer cone bipolar cells were detected in ischemic eyes, in contrast to bevacizumab and ranibizumab-treated ones. Our results demonstrate a reduced apoptosis and autophagocytosis rate after ranibizumab treatment. Furthermore, a certain protection was seen regarding functionality, RGC, and bipolar cell availability, as well as microglia activation by ranibizumab treatment after ischemic damage. Thus, ranibizumab could be an option for treatment of retinal ischemic injury.
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Zhang HB, Wang XD, Xu K, Li XG. The progress of prophylactic treatment in retinopathy of prematurity. Int J Ophthalmol 2018; 11:858-873. [PMID: 29862189 DOI: 10.18240/ijo.2018.05.24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/28/2017] [Indexed: 12/19/2022] Open
Abstract
Retinopathy of prematurity (ROP) is a retinal vascular disorder frequently found in premature infants. Different therapeutic strategies have been developed to treat ROP. However, there are still many children with ROP suffering by severe limitations in vision or even blindness. Recently, ROP has been suggested to be caused by abnormal development of the retinal vasculature, but not simply resulted by retinal neovascularization which takes about 4 to 6wk after birth in premature infants. Thus, instead of focusing on how to reduce retinal neovascularization, understanding the pathological changes and mechanisms that occur prior to retinal neovascularization is meaningful, which may lead to identify novel target(s) for the development of novel strategy to promote the healthy growth of retinal blood vessels rather than passively waiting for the appearance of retinal neovascularization and removing it by force. In this review, we discussed recent studies about, 1) the pathogenesis prior to retinal neovascularization in oxygen-induced retinopathy (OIR; a ROP in animal model) and in premature infants with ROP; 2) the preclinical and clinical research on preventive treatment of early OIR and ROP. We will not only highlight the importance of the mechanisms and signalling pathways in regulating early stage of ROP but also will provide guidance for actively exploring novel mechanisms and discovering novel treatments for early phase OIR and ROP prior to retinal neovascularization in the future.
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Affiliation(s)
- Hong-Bing Zhang
- Eye Institute of Shaanxi Province; Xi'an First Hospital, Xi'an 710002, Shaanxi Province, China
| | - Xiao-Dong Wang
- Eye Institute of Shaanxi Province; Xi'an First Hospital, Xi'an 710002, Shaanxi Province, China
| | - Kun Xu
- Eye Institute of Shaanxi Province; Xi'an First Hospital, Xi'an 710002, Shaanxi Province, China
| | - Xiao-Gang Li
- Department of Internal Medicine; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Amato R, Dal Monte M, Lulli M, Raffa V, Casini G. Nanoparticle-Mediated Delivery of Neuroprotective Substances for the Treatment of Diabetic Retinopathy. Curr Neuropharmacol 2018; 16:993-1003. [PMID: 28714394 PMCID: PMC6120116 DOI: 10.2174/1570159x15666170717115654] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 05/04/2017] [Accepted: 07/14/2017] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Diabetic retinopathy (DR) is a major complication of diabetes, characterized by extensive vascular pathology leading to vision loss. Neuronal suffering and death are also present in the diabetic retina as a result of different molecular mechanisms that are compromised or modified in response to high glucose. The aim of this paper is to highlight recent data indicating that neurodegeneration is likely to play a primary role in the development of DR and that strategies based on nanomedicine may be exploited to deliver neuroprotection to the retina. METHODS An extensive analysis of the publications dealing with the role of neuroprotection in DR and with nanoparticle-mediated drug delivery to the retina has been conducted using PubMed, with particular attention to the most recent papers. RESULTS There are important limitations related to possible systemic side effects of neuroprotective substances and to drug bioavailability in the retina such as, for instance, the amount of drug reaching the retina, the need of keeping to a minimum the number of administrations (especially, for example, in the case of intraocular injections) and the need of assuring a long-lasting, graded intraocular drug delivery. In recent years, a variety of investigations have been aimed at the exploitation of approaches of nanomedicine to enhance the pharmacokinetics and pharmacodynamic activity of intraocularly delivered drugs. In particular, we provide some preliminary results that we have obtained about the feasibility of delivering magnetic nanoparticles functionalized with a neuroprotectant to mouse eyes through intraocular injections. CONCLUSION We propose that nanoparticles functionalized with neuroprotective substances may be used to protect the diabetic retina, thus causing an impact in the design of future pharmacologic treatments for DR.
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Affiliation(s)
| | | | | | | | - Giovanni Casini
- Address correspondence to this author at the Department of Biology, University of Pisa, via S. Zeno 31, I-56127 Pisa, Italy; Tel: ++39-050-2211423; E-mail:
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Cammalleri M, Locri F, Catalani E, Filippi L, Cervia D, Dal Monte M, Bagnoli P. The Beta Adrenergic Receptor Blocker Propranolol Counteracts Retinal Dysfunction in a Mouse Model of Oxygen Induced Retinopathy: Restoring the Balance between Apoptosis and Autophagy. Front Cell Neurosci 2017; 11:395. [PMID: 29375312 PMCID: PMC5770647 DOI: 10.3389/fncel.2017.00395] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/28/2017] [Indexed: 12/29/2022] Open
Abstract
In a mouse model of oxygen induced retinopathy (OIR), beta adrenergic receptor (BAR) blockade has been shown to recover hypoxia-associated retinal damages. Although the adrenergic signaling is an important regulator of apoptotic and autophagic processes, the role of BARs in retinal cell death remains to be elucidated. The present study was aimed at investigating whether ameliorative effects of BAR blockers may occur through their coordinated action on apoptosis and autophagy. To this aim, retinas from control and OIR mice untreated or treated with propranolol, a non-selective BAR1/2 blocker, were characterized in terms of expression and localization of apoptosis and autophagy markers. The effects of propranolol on autophagy signaling were also evaluated and specific autophagy modulators were used to get functional information on the autophagic effects of BAR antagonism. Finally, propranolol effects on neurodegenerative processes were associated to an electrophysiological investigation of retinal function by recording electroretinogram (ERG). We found that retinas of OIR mice are characterized by increased apoptosis and decreased autophagy, while propranolol reduces apoptosis and stimulates autophagy. In particular, propranolol triggers autophagosome formation in bipolar, amacrine and ganglion cells that are committed to die by apoptosis in response to hypoxia. Also our data argue that propranolol, through the inhibition of the Akt-mammalian target of rapamycin pathway, activates autophagy which decreases retinal cell death. At the functional level, propranolol recovers dysfunctional ERG by recovering the amplitude of a- and b-waves, and oscillatory potentials, thus indicating an efficient restoring of retinal transduction. Overall, our results demonstrate that BAR1/2 are key regulators of retinal apoptosis/autophagy, and that BAR1/2 blockade leads to autophagy-mediated neuroprotection. Reinstating the balance between apoptotic and autophagic machines may therefore be viewed as a future goal in the treatment of retinopathies.
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Affiliation(s)
| | - Filippo Locri
- Department of Biology, University of Pisa, Pisa, Italy
| | - Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Luca Filippi
- Neonatal Intensive Care Unit, Medical Surgical Fetal-Neonatal Department, Meyer University Children's Hospital, Florence, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, Viterbo, Italy
| | | | - Paola Bagnoli
- Department of Biology, University of Pisa, Pisa, Italy
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Rai U, Thrimawithana TR, Dharmadana D, Valery C, Young SA. Release kinetics of somatostatin from self-assembled nanostructured hydrogels. Biopolymers 2017; 110. [PMID: 29127701 DOI: 10.1002/bip.23085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 10/16/2017] [Accepted: 10/24/2017] [Indexed: 11/09/2022]
Abstract
Somatostatin-14 is a native neuropeptide with widespread functions in the body. Self-assembly of somatostatin-14 into amyloid-like nanofibrils has been previously demonstrated in aqueous media. We here hypothesize that the somatostatin nanofibrils can form a stable depot that release monomers in a controlled manner. This study aims to investigate if somatostatin monomers are released from physical hydrogels formed in water and in the presence of electrolytes. The release kinetics of the somatostatin monomers is investigated for the first time. This is correlated with the rheological properties of the hydrogels formed. We demonstrate that at the concentrations tested, there is release of somatostatin monomers from the hydrogels following a novel hybrid model of zero-order and first-order release. In the presence of electrolytes, somatostatin hydrogels demonstrated higher elastic moduli (G') which correlates to the narrower and higher density of nanofibrils observed with TEM. The presence of electrolytes resulted in a slower release of the somatostatin monomers and in a lower cumulative percentage released over 48 hrs. It is questionable that the concentrations released will be therapeutically effective. However, self-assembled somatostatin hydrogels have the potential to act as a depot for ocular drug delivery.
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Affiliation(s)
- Uma Rai
- Discipline of Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Thilini R Thrimawithana
- Discipline of Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Durga Dharmadana
- Discipline of Pharmaceutical Sciences, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Celine Valery
- Discipline of Pharmaceutical Sciences, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Simon A Young
- Discipline of Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
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Amato R, Catalani E, Dal Monte M, Cammalleri M, Di Renzo I, Perrotta C, Cervia D, Casini G. Autophagy-mediated neuroprotection induced by octreotide in an ex vivo model of early diabetic retinopathy. Pharmacol Res 2017; 128:167-178. [PMID: 28970178 DOI: 10.1016/j.phrs.2017.09.022] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/21/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022]
Abstract
Neuronal injury plays a major role in diabetic retinopathy (DR). Our hypothesis was that the balance between neuronal death and survival may depend on a similar equilibrium between apoptosis and autophagy and that a neuroprotectant may act by influencing this equilibrium. Ex vivo mouse retinal explants were treated with high glucose (HG) for 10days and the somatostatin analog octreotide (OCT) was used as a neuroprotectant. Chloroquine (CQ) was used as an autophagy inhibitor. Apoptotic and autophagic markers were evaluated using western blot and immunohistochemistry. HG-treated explants displayed a significant increase of apoptosis paralleled by a significant decrease of the autophagic flux, which was likely to be due to increased activity of the autophagy regulator mTOR (mammalian target of rapamycin). Treatment with OCT rescued HG-treated retinal explants from apoptosis and determined an increase of autophagic activity with concomitant mTOR inhibition. Blocking the autophagic flux with CQ completely abolished the anti-apoptotic effect of OCT. Immunohistochemical observations showed that OCT-induced autophagy is localized to populations of bipolar and amacrine cells and to ganglion cells. These observations revealed the antithetic role of apoptosis and autophagy, highlighting their equilibrium from which neuronal survival is likely to depend. These data suggest the crucial role covered by autophagy, which could be considered as a molecular target for DR neuroprotective treatment strategies.
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Affiliation(s)
- Rosario Amato
- Department of Biology, University of Pisa, Pisa, Italy
| | - Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Pisa, Italy; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | | | - Ilaria Di Renzo
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), University of Milano, Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), University of Milano, Milano, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy.
| | - Giovanni Casini
- Department of Biology, University of Pisa, Pisa, Italy; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy.
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Joachim SC, Renner M, Reinhard J, Theiss C, May C, Lohmann S, Reinehr S, Stute G, Faissner A, Marcus K, Dick HB. Protective effects on the retina after ranibizumab treatment in an ischemia model. PLoS One 2017; 12:e0182407. [PMID: 28800629 PMCID: PMC5553852 DOI: 10.1371/journal.pone.0182407] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/18/2017] [Indexed: 12/13/2022] Open
Abstract
Retinal ischemia is common in eye disorders, like diabetic retinopathy or retinal vascular occlusion. The goal of this study was to evaluate the potential protective effects of an intravitreally injected vascular endothelial growth factor (VEGF) inhibitor (ranibizumab) on retinal cells in an ischemia animal model via immunohistochemistry (IF) and quantitative real-time PCR (PCR). A positive binding of ranibizumab to rat VEGF-A was confirmed via dot blot. One eye underwent ischemia and a subgroup received ranibizumab. A significant VEGF increase was detected in aqueous humor of ischemic eyes (p = 0.032), whereas VEGF levels were low in ranibizumab eyes (p = 0.99). Ischemic retinas showed a significantly lower retinal ganglion cell number (RGC; IF Brn-3a: p<0.001, IF RBPMS: p<0.001; PCR: p = 0.002). The ranibizumab group displayed fewer RGCs (IF Brn-3a: 0.3, IF RBPMS: p<0.001; PCR: p = 0.007), but more than the ischemia group (IF Brn-3a: p = 0.04, IF RBPMS: p = 0.03). Photoreceptor area was decreased after ischemia (IF: p = 0.049; PCR: p = 0.511), while the ranibizumab group (IF: p = 0.947; PCR: p = 0.122) was comparable to controls. In the ischemia (p<0.001) and ranibizumab group (p<0.001) a decrease of ChAT+ amacrine cells was found, which was less prominent in the ranibizumab group. VEGF-receptor 2 (VEGF-R2; IF: p<0.001; PCR: p = 0.021) and macroglia (GFAP; IF: p<0.001; PCR: p<0.001) activation was present in ischemic retinas. The activation was weaker in ranibizumab retinas (VEGF-R2: IF: p = 0.1; PCR: p = 0.03; GFAP: IF: p = 0.1; PCR: p = 0.015). An increase in the number of total (IF: p = 0.003; PCR: p = 0.023) and activated microglia (IF: p<0.001; PCR: p = 0.009) was detected after ischemia. These levels were higher in the ranibizumab group (Iba1: IF: p<0.001; PCR: p = 0.018; CD68: IF: p<0.001; PCR: p = 0.004). Our findings demonstrate that photoreceptors and RGCs are protected by ranibizumab treatment. Only amacrine cells cannot be rescued. They seem to be particularly sensitive to ischemic damage and need maybe an earlier intervention.
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Affiliation(s)
- Stephanie C. Joachim
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23–25, Bochum, Germany
- * E-mail:
| | - Marina Renner
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23–25, Bochum, Germany
| | - Jacqueline Reinhard
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Carsten Theiss
- Department of Cytology, Faculty of Medicine, Ruhr-University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Caroline May
- Medizinisches Proteom-Center, Ruhr-University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Stephanie Lohmann
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23–25, Bochum, Germany
| | - Sabrina Reinehr
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23–25, Bochum, Germany
| | - Gesa Stute
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23–25, Bochum, Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center, Ruhr-University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - H. Burkhard Dick
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23–25, Bochum, Germany
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Li M, Wang S, Wang S, Zhang L, Wu D, Yang R, Ji A, Li Y, Wang J. Occludin downregulation in high glucose is regulated by SSTR 2 via the VEGF/NRP1/Akt signaling pathway in RF/6A cells. Exp Ther Med 2017; 14:1732-1738. [PMID: 28810643 DOI: 10.3892/etm.2017.4651] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 03/23/2017] [Indexed: 01/20/2023] Open
Abstract
Occludin is a tight junction protein that forms the permeability barrier, which is typically disturbed in ischemic associated diseases. The aim of the present study was to determine whether somatostatin receptor 2 (SSTR2) in RF/6A cells is involved in the modulation of the downregulation of occludin induced by high glucose, and to evaluate the implicated molecules. RF/6A cells were maintained in Dulbecco's modified Eagle medium and treated with 0 or 30 mM D-glucose. SSTR2 agonist octreotide (OCT), OCT with SSTR2 antagonist cycle-somatostatin (c-SOM) and neuropilin 1 (NRP1) inhibitor ATWLPPR, respectively, were administered to RF/6A cells under high glucose conditions. Cell apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling. Western blot analysis was used to detect the protein expression level of SSTR2, occludin, vascular endothelial growth factor (VEGF), protein kinase B (Akt), phosphorylated Akt (p-Akt), extracellular signal-related kinases (ERK) and p-ERK proteins. The amount of VEGF released was determined by ELISA. Notably, the level of occludin reduced significantly under high glucose conditions. The results indicated that the administration of OCT prevented the reduction of occludin induced by high glucose, and co-administration with c-SOM reversed the effect of OCT. Increased VEGF secretion and expression of VEGF, p-Akt and p-ERK in RF/6A cells induced by high glucose were inhibited by OCT. ATWLPPR also prevented the downregulation of occludin, but did not inhibit p-Akt and p-ERK levels under high glucose conditions. The current study concluded that the activation of SSTR2 prevents high glucose-induced occludin downregulation in RF/6A cells, and VEGF, NRP1, p-Akt and p-ERK were implicated in this process. The pharmacological effects of SSTR2 targeting to endothelium may be used to assess the role of resistance of permeability and anti-inflammation.
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Affiliation(s)
- Mengling Li
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Shuaiwei Wang
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Songjiang Wang
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Lei Zhang
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Dongdong Wu
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Ruisheng Yang
- Department of Clinical Laboratory, The First Affiliated Hospital of Henan University, Kaifeng, Henan 475001, P.R. China
| | - Ailing Ji
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Yanzhang Li
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
| | - Jun Wang
- Department of Physiology, Henan University School of Medicine, Kaifeng, Henan 475004, P.R. China
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29
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Current Evidence for a Role of Neuropeptides in the Regulation of Autophagy. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5856071. [PMID: 28593174 PMCID: PMC5448050 DOI: 10.1155/2017/5856071] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/30/2017] [Indexed: 12/14/2022]
Abstract
Neuropeptides drive a wide diversity of biological actions and mediate multiple regulatory functions involving all organ systems. They modulate intercellular signalling in the central and peripheral nervous systems as well as the cross talk among nervous and endocrine systems. Indeed, neuropeptides can function as peptide hormones regulating physiological homeostasis (e.g., cognition, blood pressure, feeding behaviour, water balance, glucose metabolism, pain, and response to stress), neuroprotection, and immunomodulation. We aim here to describe the recent advances on the role exerted by neuropeptides in the control of autophagy and its molecular mechanisms since increasing evidence indicates that dysregulation of autophagic process is related to different pathological conditions, including neurodegeneration, metabolic disorders, and cancer.
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Catalani E, Proietti Serafini F, Zecchini S, Picchietti S, Fausto AM, Marcantoni E, Buonanno F, Ortenzi C, Perrotta C, Cervia D. Natural products from aquatic eukaryotic microorganisms for cancer therapy: Perspectives on anti-tumour properties of ciliate bioactive molecules. Pharmacol Res 2016; 113:409-420. [PMID: 27650755 DOI: 10.1016/j.phrs.2016.09.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/12/2016] [Accepted: 09/16/2016] [Indexed: 11/27/2022]
Abstract
Several modern drugs, including those for cancer therapy, have been isolated from natural sources, are based on natural products and its derivatives, or mime natural products. Some of them are in clinical use, others in clinical trials. The success of natural products in drug discovery is related to their biochemical characteristics and to the technologic methods used to study their feature. Natural compounds may acts as chemo-preventive agents and as factors that increase therapeutic efficacy of existing drugs, thus overcoming cancer cell drug resistance that is the main factor determining the failure in conventional chemotherapy. Water environment, because of its physical and chemical conditions, shows an extraordinary collection of natural biological substances with an extensive structural and functional diversity. The isolation of bioactive molecules has been reported from a great variety of aquatic organisms; however, the therapeutic application of molecules from eukaryotic microorganisms remains inadequately investigated and underexploited on a systematic basis. Herein we describe the biological activities in mammalian cells of selected substances isolated from ciliates, free-living protozoa common almost everywhere there is water, focusing on their anti-tumour actions and their possible therapeutic activity. In particular, we unveil the cellular and molecular machine mediating the effects of cell type-specific signalling protein pheromone Er-1 and secondary metabolites, i.e. euplotin C and climacostol, in cancer cells. To support the feasibility of climacostol-based approaches, we also present novel findings and report additional mechanisms of action using both in vitro and in vivo models of mouse melanomas, with the scope of highlighting new frontiers that can be explored also in a therapeutic perspective. The high skeletal chemical difference of ciliate compounds, their sustainability and availability, also through the use of new organic synthesis/modifications processes, and the results obtained so far in biological studies provide a rationale to consider some of them a potential resource for the design of new anti-cancer drugs.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Francesca Proietti Serafini
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Silvia Zecchini
- Unit of Clinical Pharmacology, University Hospital "Luigi Sacco"-ASST Fatebenefratelli Sacco, Milano, Italy
| | - Simona Picchietti
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Anna Maria Fausto
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Enrico Marcantoni
- School of Sciences and Technologies, Section of Chemistry, Università degli Studi di Camerino, Italy
| | - Federico Buonanno
- Laboratory of Protistology and Biology Education, Department of Education, Cultural Heritage and Tourism, Università degli Studi di Macerata, Italy
| | - Claudio Ortenzi
- Laboratory of Protistology and Biology Education, Department of Education, Cultural Heritage and Tourism, Università degli Studi di Macerata, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, Italy.
| | - Davide Cervia
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy; Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, Italy.
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31
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Moran EP, Wang Z, Chen J, Sapieha P, Smith LEH, Ma JX. Neurovascular cross talk in diabetic retinopathy: Pathophysiological roles and therapeutic implications. Am J Physiol Heart Circ Physiol 2016; 311:H738-49. [PMID: 27473938 DOI: 10.1152/ajpheart.00005.2016] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 07/18/2016] [Indexed: 12/19/2022]
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population in developed countries, and its prevalence will increase as the global incidence of diabetes grows exponentially. DR begins with an early nonproliferative stage in which retinal blood vessels and neurons degenerate as a consequence of chronic hyperglycemia, resulting in vasoregression and persistent retinal ischemia, metabolic disequilibrium, and inflammation. This is conducive to overcompensatory pathological neovascularization associated with advanced proliferative DR. Although DR is considered a microvascular complication, the retinal microvasculature is intimately associated with and governed by neurons and glia; neurodegeneration, neuroinflammation, and dysregulation of neurovascular cross talk are responsible in part for vascular abnormalities in both early nonproliferative DR and advanced proliferative DR. Neuronal activity directly regulates microvascular dilation and blood flow in the process of neurovascular coupling. Retinal neurons also secrete guidance cues in response to injury, ischemia, or metabolic stress that may either promote or suppress vascular outgrowth, either alleviating or exacerbating DR, contingent on the stage of disease and retinal microenvironment. Neurodegeneration, impaired neurovascular coupling, and dysregulation of neuronal guidance cues are key events in the pathogenesis of DR, and correcting these events may prevent or delay development of advanced DR. The review discusses the mechanisms of neurovascular cross talk and its dysregulation in DR, and their potential therapeutic implications.
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Affiliation(s)
- Elizabeth P Moran
- Depatment of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; Harold Hamm Diabetes Center, Oklahoma City, Oklahoma
| | - Zhongxiao Wang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Jing Chen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Przemyslaw Sapieha
- Departments of Ophthalmology, Biochemistry & Molecular Medicine, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, Quebec, Canada
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Jian-Xing Ma
- Depatment of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; Harold Hamm Diabetes Center, Oklahoma City, Oklahoma;
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Abstract
Diabetic retinopathy (DR) is a common complication of diabetes mellitus and is a major cause of vision loss in middle-aged and elderly people. One-third of people with diabetes have DR. Severe stages of DR include proliferative DR, caused by the abnormal growth of new retinal blood vessels, and diabetic macular oedema, in which there is exudation and oedema in the central part of the retina. DR is strongly associated with a prolonged duration of diabetes, hyperglycaemia and hypertension. It is traditionally regarded as a microvascular disease, but retinal neurodegeneration is also involved. Complex interrelated pathophysiological mechanisms triggered by hyperglycaemia underlie the development of DR. These mechanisms include genetic and epigenetic factors, increased production of free radicals, advanced glycosylation end products, inflammatory factors and vascular endothelial growth factor (VEGF). Optimal control of blood glucose and blood pressure in individuals with diabetes remains the cornerstone for preventing the development and arresting the progression of DR. Anti-VEGF therapy is currently indicated for diabetic macular oedema associated with vision loss, whereas laser photocoagulation prevents severe vision loss in eyes with proliferative DR. These measures, together with increasing public awareness and access to regular screening for DR with retinal photography, and the development of new treatments to address early disease stages, will lead to better outcomes and prevent blindness for patients with DR.
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Dal Monte M, Casini G. Indirect blockade of vascular endothelial growth factor: the potential for eye disease therapy. EXPERT REVIEW OF OPHTHALMOLOGY 2016. [DOI: 10.1586/17469899.2016.1131609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hernández C, Dal Monte M, Simó R, Casini G. Neuroprotection as a Therapeutic Target for Diabetic Retinopathy. J Diabetes Res 2016; 2016:9508541. [PMID: 27123463 PMCID: PMC4830713 DOI: 10.1155/2016/9508541] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/29/2016] [Accepted: 03/16/2016] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy (DR) is a multifactorial progressive disease of the retina and a leading cause of vision loss. DR has long been regarded as a vascular disorder, although neuronal death and visual impairment appear before vascular lesions, suggesting an important role played by neurodegeneration in DR and the appropriateness of neuroprotective strategies. Upregulation of vascular endothelial growth factor (VEGF), the main target of current therapies, is likely to be one of the first responses to retinal hyperglycemic stress and VEGF may represent an important survival factor in early phases of DR. Of central importance for clinical trials is the detection of retinal neurodegeneration in the clinical setting, and spectral domain optical coherence tomography seems the most indicated technique. Many substances have been tested in animal studies for their neuroprotective properties and for possible use in humans. Perhaps, the most intriguing perspective is the use of endogenous neuroprotective substances or nutraceuticals. Together, the data point to the central role of neurodegeneration in the pathogenesis of DR and indicate neuroprotection as an effective strategy for treating this disease. However, clinical trials to determine not only the effectiveness and safety but also the compliance of a noninvasive route of drug administration are needed.
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Affiliation(s)
- Cristina Hernández
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabolicas Asociadas) and Diabetes and Metabolism Research Unit, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autonoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
- *Cristina Hernández: and
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Rafael Simó
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabolicas Asociadas) and Diabetes and Metabolism Research Unit, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autonoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
| | - Giovanni Casini
- Department of Biology, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
- *Giovanni Casini:
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Perrotta C, De Palma C, Clementi E, Cervia D. Hormones and immunity in cancer: are thyroid hormones endocrine players in the microglia/glioma cross-talk? Front Cell Neurosci 2015; 9:236. [PMID: 26157361 PMCID: PMC4477169 DOI: 10.3389/fncel.2015.00236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/11/2015] [Indexed: 11/16/2022] Open
Abstract
Accumulating evidence indicates that the endocrine and immune systems engage in complex cross-talks in which a prominent role is played by thyroid hormones (THs). The increase of resident vs. monocyte recruited macrophages was shown to be an important effector of the TH 3,3′,5′-Triiodo-L-thyronine (T3)-induced protection against inflammation and a key role of T3 in inhibiting the differentiation of peripheral monocytes into macrophages was observed. Herein, we report on the role of T3 as a modulator of microglia, the specialized macrophages of the central nervous system (CNS). Mounting evidence supports a role of microglia and macrophages in the growth and invasion of malignant glioma. In this respect, we unveil the putative involvement of T3 in the microglia/glioma cell communication. Since THs are known to cross the blood-brain barrier, we suggest that T3 not only exerts a direct modulation of brain cancer cell itself but also indirectly promotes glioma growth through a modulation of microglia. Our observations expand available information on the role of TH system in glioma and its microenvironment and highlight the endocrine modulation of microglia as an important target for future therapeutic development of glioma treatments.
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Affiliation(s)
- Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, University Hospital "Luigi Sacco", Università di Milano Milano, Italy
| | - Clara De Palma
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, University Hospital "Luigi Sacco", Università di Milano Milano, Italy
| | - Emilio Clementi
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, University Hospital "Luigi Sacco", Università di Milano Milano, Italy ; Scientific Institute IRCCS Eugenio Medea Bosisio Parini, Italy
| | - Davide Cervia
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, University Hospital "Luigi Sacco", Università di Milano Milano, Italy ; Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università della Tuscia, Largo dell'Università snc Viterbo, Italy
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Acetyl-11-keto-β-boswellic acid reduces retinal angiogenesis in a mouse model of oxygen-induced retinopathy. Exp Eye Res 2015; 135:67-80. [DOI: 10.1016/j.exer.2015.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 02/27/2015] [Accepted: 04/21/2015] [Indexed: 11/22/2022]
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Therapeutic uses of somatostatin and its analogues: Current view and potential applications. Pharmacol Ther 2015; 152:98-110. [PMID: 25956467 DOI: 10.1016/j.pharmthera.2015.05.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/28/2015] [Indexed: 01/22/2023]
Abstract
Somatostatin is an endogeneous cyclic tetradecapeptide hormone that exerts multiple biological activities via five ubiquitously distributed receptor subtypes. Classified as a broad inhibitory neuropeptide, somatostatin has anti-secretory, anti-proliferative and anti-angiogenic effects. The clinical use of native somatostatin is limited by a very short half-life (1 to 3min) and the broad spectrum of biological responses. Thus stable, receptor-selective agonists have been developed. The majority of these somatostatin therapeutic agonists bind strongly to two of the five receptor subtypes, although recently an agonist of wider affinity has been introduced. Somatostatin agonists are established in the treatment of acromegaly with recently approved indications in the therapy of neuroendocrine tumours. Potential therapeutic uses for somatostatin analogues include diabetic complications like retinopathy, nephropathy and obesity, due to inhibition of IGF-1, VEGF together with insulin secretion and effects upon the renin-angiotensin-aldosterone system. Wider uses in anti-neoplastic therapy may also be considered and recent studies have further revealed anti-inflammatory and anti-nociceptive effects. This review provides a comprehensive, current view of the biological functions of somatostatin and potential therapeutic uses, informed by the wide range of pharmacological advances reported since the last published review in 2004 by P. Dasgupta. The pharmacology of somatostatin receptors is explained, the current uses of somatostatin agonists are discussed, and the potential future of therapeutic applications is explored.
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Therapeutic Effects of PPAR α on Neuronal Death and Microvascular Impairment. PPAR Res 2015; 2015:595426. [PMID: 25705219 PMCID: PMC4326216 DOI: 10.1155/2015/595426] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/09/2015] [Accepted: 01/09/2015] [Indexed: 12/30/2022] Open
Abstract
Peroxisome-proliferator activated receptor-alpha (PPARα) is a broadly expressed nuclear hormone receptor and is a transcription factor for diverse target genes possessing a PPAR response element (PPRE) in the promoter region. The PPRE is highly conserved, and PPARs thus regulate transcription of an extensive array of target genes involved in energy metabolism, vascular function, oxidative stress, inflammation, and many other biological processes. PPARα has potent protective effects against neuronal cell death and microvascular impairment, which have been attributed in part to its antioxidant and anti-inflammatory properties. Here we discuss PPARα's effects in neurodegenerative and microvascular diseases and also recent clinical findings that identified therapeutic effects of a PPARα agonist in diabetic microvascular complications.
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Li J, Wang JJ, Zhang SX. NADPH oxidase 4-derived H2O2 promotes aberrant retinal neovascularization via activation of VEGF receptor 2 pathway in oxygen-induced retinopathy. J Diabetes Res 2015; 2015:963289. [PMID: 25866826 PMCID: PMC4381975 DOI: 10.1155/2015/963289] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 02/24/2015] [Accepted: 02/24/2015] [Indexed: 01/23/2023] Open
Abstract
NADPH oxidase 4 (Nox4) is a major isoform of NADPH oxidase in retinal endothelial cells. Our previous study suggests that upregulation of Nox4 in retinal endothelial cells contributes to retinal vascular leakage in diabetes. In the current study, we investigated the role and mechanism of Nox4 in regulation of retinal neovascularization (NV), a hallmark of proliferative diabetic retinopathy (PDR), using a mouse model of oxygen-induced retinopathy (OIR). Our results confirmed that Nox4 was expressed predominantly in retinal vasculature of mouse retina. Retinal expression of Nox4 was markedly increased in OIR, in parallel with enhanced phosphorylation of ERK. In human retinal microvascular endothelial cells (HRECs), overexpression of Nox4 by adenovirus significantly increased extracellular H2O2 generation, resulting in intensified VEGFR2 activation and exacerbated angiogenesis upon VEGF stimulation. In contrast, silencing Nox4 expression or scavenging H2O2 by polyethylene glycol- (PEG-) conjugated catalase inhibited endothelial migration, tube formation, and VEGF-induced activation of VEGFR2 signaling. Importantly, knockdown of retinal Nox4 by adenovirus-delivered siRNA significantly reduced ERK activation and attenuated retinal NV formation in OIR. Taken together, our data indicate that Nox4 promotes retinal NV formation through H2O2/VEGFR2/ERK signaling pathway. Reducing retinal Nox4 expression may represent a promising therapeutic approach for neovascular retinal diseases such as PDR.
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Affiliation(s)
- Jingming Li
- The First Affiliated Hospital of Xi'an Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi 710061, China
- Department of Medicine, Endocrinology and Diabetes, Harold Hamm Oklahoma Diabetes Center, University of Oklahoma Health Sciences Center, 941 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
| | - Joshua J. Wang
- Department of Medicine, Endocrinology and Diabetes, Harold Hamm Oklahoma Diabetes Center, University of Oklahoma Health Sciences Center, 941 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
- Department of Ophthalmology & Ira G. Ross Eye Institute, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14214, USA
- SUNY Eye Institute, Buffalo, NY 14214, USA
| | - Sarah X. Zhang
- Department of Medicine, Endocrinology and Diabetes, Harold Hamm Oklahoma Diabetes Center, University of Oklahoma Health Sciences Center, 941 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
- Department of Ophthalmology & Ira G. Ross Eye Institute, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14214, USA
- SUNY Eye Institute, Buffalo, NY 14214, USA
- *Sarah X. Zhang:
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40
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The β-adrenergic system as a possible new target for pharmacologic treatment of neovascular retinal diseases. Prog Retin Eye Res 2014; 42:103-29. [DOI: 10.1016/j.preteyeres.2014.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/30/2014] [Accepted: 06/05/2014] [Indexed: 12/31/2022]
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41
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Hernández C, Simó-Servat O, Simó R. Somatostatin and diabetic retinopathy: current concepts and new therapeutic perspectives. Endocrine 2014; 46:209-14. [PMID: 24627166 DOI: 10.1007/s12020-014-0232-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/28/2014] [Indexed: 12/15/2022]
Abstract
Somatostatin (SST) is abundantly produced by the human retina, and the main source is the retinal pigment epithelium (RPE). SST exerts relevant functions in the retina (neuromodulation, angiostatic, and anti-permeability actions) by interacting with SST receptors (SSTR) that are also expressed in the retina. In the diabetic retina, a downregulation of SST production does exist. In this article, we give an overview of the mechanisms by which this deficit of SST participates in the main pathogenic mechanisms involved in diabetic retinopathy (DR): neurodegeneration, neovascularization, and vascular leakage. In view of the relevant SST functions in the retina and the reduction of SST production in the diabetic eye, SST replacement has been proposed as a new target for treatment of DR. This could be implemented by intravitreous injections of SST analogs or gene therapy, but this is an aggressive route for the early stages of DR. Since topical administration of SST has been effective in preventing retinal neurodegeneration in STZ-induced diabetic rats, it seems reasonable to test this new approach in humans. In this regard, the results of the ongoing clinical trial EUROCONDOR will provide useful information. In conclusion, SST is a natural neuroprotective and antiangiogenic factor synthesized by the retina which is downregulated in the diabetic eye and, therefore, its replacement seems a rational approach for treating DR. However, clinical trials will be needed to establish the exact position of targeting SST in the treatment of this disabling complication of diabetes.
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Affiliation(s)
- Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Pg. Vall d'Hebron 119-129.08035, Barcelona, Spain
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42
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Phenotypes and biomarkers of diabetic retinopathy. Prog Retin Eye Res 2014; 41:90-111. [PMID: 24680929 DOI: 10.1016/j.preteyeres.2014.03.003] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/11/2014] [Accepted: 03/18/2014] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy (DR) remains a major cause of blindness as the prevalence of diabetes is expected to approximately double globally between 2000 and 2030. DR progresses over time at different rates in different individuals with only a limited number developing significant vision loss due to the two major vision-threatening complications, clinically significant macular edema and proliferative retinopathy. Good metabolic control is important to prevent and delay progression, but whereas some patients escape vision loss even with poor control, others develop vision loss despite good metabolic control. Our research group has been able to identify three different DR phenotypes characterized by different dominant retinal alterations and different risks of progression to vision-threatening complications. Microaneurysm turnover has been validated as a prognostic biomarker of development of clinically significant macular edema, whereas subclinical macular edema identified by OCT and mfERG appear to be also good candidates as organ-specific biomarkers of DR. Hemoglobin A1c remains the only confirmed systemic prognostic biomarker of DR progression. The availability of biomarkers of DR progression and the identification of different phenotypes of DR with different risks for development of vision-threatening complications offers new perspectives for understanding DR and for its personalized management.
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43
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Kunjara S, Greenbaum AL, Sochor M, Flyvbjerg A, Grønbaek H, McLean P. Effects of long-acting somatostatin analogues on redox systems in rat lens in experimental diabetes. Int J Exp Pathol 2014; 95:95-100. [PMID: 24602114 DOI: 10.1111/iep.12069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 11/26/2013] [Indexed: 10/25/2022] Open
Abstract
The effects of long-acting somatostatin analogues, angiopeptin (AGP) and Sandostatin (SMS), on the early decline in the lens content of glutathione (GSH), ATP and NADPH and increase in sorbitol were studied in STZ diabetic rats, and comparison was made with the effect of insulin. Three factors prompted this study: (i) the known increase in IGF-1 in ocular tissue in diabetes and antagonistic effect of somatostatins, (ii) the known effect of IGF-1 in increasing lens aldose reductase and (iii) the lack of effect of somatostatins on diabetic hyperglycaemia, the latter enabling a differentiation to be made between effects of hyperglycaemia per se and site(s) of IGF-1/somatostatins. All four metabolites studied showed a significant restoration towards the normal control level after 7 days of treatment with AGP and SMS, and AGP was more effective on levels of GSH and ATP. A significant correlation was found between GSH and ATP across all groups at 7 days treatment. The redox state changes in diabetes include both NADP+/NADPH and NAD+/NADH in the conversion of glucose to sorbitol and via sorbitol dehydrogenase to fructose with a linked decrease in ATP formation via NAD+/NADH regulation of the glycolytic pathway. The interlinked network of change includes the requirement for ATP in the synthesis of GSH. The present study points to possible loci of action of somatostatins in improving metabolic parameters in the diabetic rat lens via effects on aldose reductase and/or glucose transport at GLUT 3.
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Affiliation(s)
- Sirilaksana Kunjara
- Division of Biosciences, Research Department of Cell and Developmental Biology, University College London, London, UK
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44
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D'Alessandro A, Cervia D, Catalani E, Gevi F, Zolla L, Casini G. Protective effects of the neuropeptides PACAP, substance P and the somatostatin analogue octreotide in retinal ischemia: a metabolomic analysis. MOLECULAR BIOSYSTEMS 2014; 10:1290-304. [PMID: 24514073 DOI: 10.1039/c3mb70362b] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ischemia is a primary cause of neuronal death in retinal diseases and the somatostatin subtype receptor 2 agonist octreotide (OCT) is known to decrease ischemia-induced retinal cell death. Using a recently optimized ex vivo mouse model of retinal ischemia, we tested the anti-ischemic potential of two additional neuropeptides, pituitary adenylate cyclase activating peptide (PACAP) and substance P (SP), and monitored the major changes occurring at the metabolic level. Metabolomics analyses were performed via fast HPLC online using a microTOF-Q MS instrument, a workflow that is increasingly becoming the gold standard in the field of metabolomics. The metabolomic approach allowed detection of the most significant alterations induced in the retina by ischemia and of the significance of the protective effects exerted by OCT, PACAP or SP. All treatments were shown to reduce ischemia-induced cell death, vascular endothelial growth factor over-expression and glutamate release. The metabolomic analysis showed that OCT and, to a lesser extent, also PACAP or SP, were able to counteract the ischemia-induced oxidative stress and to promote, with various efficacies, (i) decreased accumulation of glutamate and normalization of glutathione homeostasis; (ii) reduced build-up of α-ketoglutarate, which might serve as a substrate for the enhanced biosynthesis of glutamate in response to ischemia; (iii) reduced accumulation of peroxidized lipids and inflammatory mediators; (iv) the normalization of glycolytic fluxes and thus preventing the over-accumulation of lactate or either promoting the down-regulation of the glyoxalate anti-oxidant system; (v) a reduced metabolic shift from glycolysis towards the PPP or either a blockade at the non-oxidative phase of the PPP; and (vi) tuning down of purine metabolism. In addition, OCT seemed to stimulate nitric oxide production. None of the treatments was able to restore ATP production, although ATP reservoirs were partly replenished by OCT, PACAP or SP. These data indicate that, in addition to that of somatostatin, peptidergic systems such as those of PACAP and SP deserve attention in view of peptide-based therapies to treat ischemic retinal disorders.
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Affiliation(s)
- Angelo D'Alessandro
- Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, L.go dell'Università snc, I-01100 Viterbo, Italy.
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45
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Simó R, Hernández C. Neurodegeneration in the diabetic eye: new insights and therapeutic perspectives. Trends Endocrinol Metab 2014; 25:23-33. [PMID: 24183659 DOI: 10.1016/j.tem.2013.09.005] [Citation(s) in RCA: 323] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/02/2013] [Accepted: 09/27/2013] [Indexed: 11/29/2022]
Abstract
Diabetic retinopathy (DR), one of the leading causes of preventable blindness, has been considered a microcirculatory disease of the retina. However, there is emerging evidence to suggest that retinal neurodegeneration is an early event in the pathogenesis of DR, which participates in the development of microvascular abnormalities. Therefore, the study of the underlying mechanisms leading to neurodegeneration and the identification of the mediators in the crosstalk between neurodegeneration and microangiopathy will be essential for the development of new therapeutic strategies. In this review, an updated discussion of the mechanisms involved in neurodegeneration, as well as the link between neurodegeneration and microangiopathy, is presented. Finally, the therapeutic implications and new perspectives based on identifying those patients with retinal neurodegeneration are given.
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Affiliation(s)
- Rafael Simó
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabólicas Asociadas) and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca (VHIR), Universitat Autónoma de Barcelona, 08035 Barcelona, Spain.
| | - Cristina Hernández
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabólicas Asociadas) and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca (VHIR), Universitat Autónoma de Barcelona, 08035 Barcelona, Spain
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46
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Szabadfi K, Pinter E, Reglodi D, Gabriel R. Neuropeptides, trophic factors, and other substances providing morphofunctional and metabolic protection in experimental models of diabetic retinopathy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:1-121. [PMID: 24952915 DOI: 10.1016/b978-0-12-800179-0.00001-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vision is the most important sensory modality for many species, including humans. Damage to the retina results in vision loss or even blindness. One of the most serious complications of diabetes, a disease that has seen a worldwide increase in prevalence, is diabetic retinopathy. This condition stems from consequences of pathological metabolism and develops in 75% of patients with type 1 and 50% with type 2 diabetes. The development of novel protective drugs is essential. In this review we provide a description of the disease and conclude that type 1 diabetes and type 2 diabetes lead to the same retinopathy. We evaluate existing experimental models and recent developments in finding effective compounds against this disorder. In our opinion, the best models are the long-term streptozotocin-induced diabetes and Otsuka Long-Evans Tokushima Fatty and spontaneously diabetic Torii rats, while the most promising substances are topically administered somatostatin and pigment epithelium-derived factor analogs, antivasculogenic substances, and systemic antioxidants. Future drug development should focus on these.
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Affiliation(s)
- Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary; Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary.
| | - Erika Pinter
- Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary; Department of Pharmacology and Pharmacotherapy, University of Pecs, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, PTE MTA Lendulet-PACAP Research Team, University of Pecs, Pecs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary; Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary
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47
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Gábriel R. Neuropeptides and diabetic retinopathy. Br J Clin Pharmacol 2013; 75:1189-201. [PMID: 23043302 DOI: 10.1111/bcp.12003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/02/2012] [Indexed: 12/21/2022] Open
Abstract
Diabetic retinopathy, a common complication of diabetes, develops in 75% of patients with type 1 and 50% of patients with type 2 diabetes, progressing to legal blindness in about 5%. In the recent years, considerable efforts have been put into finding treatments for this condition. It has been discovered that peptidergic mechanisms (neuropeptides and their analogues, activating a diverse array of signal transduction pathways through their multiple receptors) are potentially important for consideration in drug development strategies. A considerable amount of knowledge has been accumulated over the last three decades on human retinal neuropeptides and those elements in the pathomechanisms of diabetic retinopathy which might be related to peptidergic signal transduction. Here, human retinal neuropeptides and their receptors are reviewed, along with the theories relevant to the pathogenesis of diabetic retinopathy both in humans and in experimental models. By collating this information, the curative potential of certain neupeptides and their analogues/antagonists can also be discussed, along with the existing clinical treatments of diabetic retinopathy. The most promising peptidergic pathways for which treatment strategies may be developed at present are stimulation of the somatostatin-related pathway and the pituitary adenylyl cyclase-activating polypeptide-related pathway or inhibition of angiotensinergic mechanisms. These approaches may result in the inhibition of vascular endothelial growth factor production and neuronal apoptosis; therefore, both the optical quality of the image and the processing capability of the neural circuit in the retina may be saved.
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Affiliation(s)
- Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, H-7621, Pécs, Hungary.
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48
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Cervia D, Casini G. The Neuropeptide Systems and their Potential Role in the Treatment of Mammalian Retinal Ischemia: A Developing Story. Curr Neuropharmacol 2013; 11:95-101. [PMID: 23814541 PMCID: PMC3580795 DOI: 10.2174/157015913804999423] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/30/2012] [Accepted: 08/09/2012] [Indexed: 12/23/2022] Open
Abstract
The multiplicity of peptidergic receptors and of the transduction pathways they activate offers the possibility of important advances in the development of specific drugs for clinical treatment of central nervous system disorders. Among them, retinal ischemia is a common clinical entity and, due to relatively ineffective treatment, remains a common cause of visual impairment and blindness. Ischemia is a primary cause of neuronal death, and it can be considered as a sort of final common pathway in retinal diseases leading to irreversible morphological damage and vision loss. Neuropeptides and their receptors are widely expressed in mammalian retinas, where they exert multifaceted functions both during development and in the mature animal. In particular, in recent years somatostatin and pituitary adenylate cyclase activating peptide have been reported to be highly protective against retinal cell death caused by ischemia, while data on opioid peptides, angiotensin II, and other peptides have also been published. This review provides a rationale for harnessing the peptidergic receptors as a potential target against retinal neuronal damages which occur during ischemic retinopathies.
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Affiliation(s)
- D Cervia
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), University of Tuscia, Viterbo, Italy
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Hernández C, García-Ramírez M, Corraliza L, Fernández-Carneado J, Farrera-Sinfreu J, Ponsati B, González-Rodríguez A, Valverde AM, Simó R. Topical administration of somatostatin prevents retinal neurodegeneration in experimental diabetes. Diabetes 2013; 62:2569-78. [PMID: 23474487 PMCID: PMC3712066 DOI: 10.2337/db12-0926] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retinal neurodegeneration is an early event in the pathogenesis of diabetic retinopathy (DR). Somatostatin (SST) is an endogenous neuroprotective peptide that is downregulated in the diabetic eye. The aim of the study was to test the usefulness of topical administration of SST in preventing retinal neurodegeneration. For this purpose, rats with streptozotocin-induced diabetes mellitus (STZ-DM) were treated with either SST eye drops or vehicle for 15 days. Nondiabetic rats treated with vehicle served as a control group. Functional abnormalities were assessed by electroretinography (ERG), and neurodegeneration was assessed by measuring glial activation and the apoptotic rate. In addition, proapoptotic (FasL, Bid, and activation of caspase-8 and caspase-3) and survival signaling pathways (BclxL) were examined. Intraretinal concentrations of glutamate and its main transporter glutamate/aspartate transporter (GLAST) were also determined. Treatment with SST eye drops prevented ERG abnormalities, glial activation, apoptosis, and the misbalance between proapoptotic and survival signaling detected in STZ-DM rats. In addition, SST eye drops inhibited glutamate accumulation in the retina and GLAST downregulation induced by diabetes mellitus. We conclude that topical administration of SST has a potent effect in preventing retinal neurodegeneration induced by diabetes mellitus. In addition, our findings open up a new preventive pharmacological strategy targeted to early stages of DR.
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Affiliation(s)
- Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.
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Wang L, Fan W, Cai P, Fan M, Zhu X, Dai Y, Sun C, Cheng Y, Zheng P, Zhao BQ. Recombinant ADAMTS13 reduces tissue plasminogen activator-induced hemorrhage after stroke in mice. Ann Neurol 2012; 73:189-98. [PMID: 23280993 DOI: 10.1002/ana.23762] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 08/13/2012] [Accepted: 09/04/2012] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Tissue plasminogen activator (tPA) is approved for treatment of acute ischemic stroke, but it increases the risk of cerebral hemorrhage. Accumulating evidence suggests that von Willebrand factor (VWF) plays a pivotal role in thrombus formation and microcirculatory disturbances after ischemic stroke. By cleaving VWF, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) protects mice from stroke. Therefore, we hypothesized that recombinant ADAMTS13 (rADAMTS13) could increase the safety of tPA thrombolysis in stroke. METHODS We examined blood-brain barrier (BBB) permeability after intraventricular injection of tPA, VWF, and rADAMTS13 in nonischemic mice. We investigated the role of rADAMTS13 on reducing tPA-induced BBB dysfunction and cerebral hemorrhage in a mouse stroke model. RESULTS Intraventricular injection of tPA or VWF under nonischemic conditions resulted in a significant increase in BBB permeability. In contrast, rADAMTS13 blocked both tPA- and VWF-induced BBB opening. BBB disruption following stroke was exacerbated by intravenous administration of tPA, but this was attenuated by injection of rADAMTS13. Correspondingly, tPA-associated hemorrhage after stroke was significantly reduced by rADAMTS13. The antihemorrhagic effect of rADAMTS13 was reversed by injection of recombinant VWF. We also showed that rADAMTS13 inhibited tPA-mediated upregulation of vascular endothelial growth factor (VEGF) in vascular endothelium after stroke. The upregulation of VEGF was suppressed by either an Akt inhibitor wortmannin or a Rho kinase inhibitor fasudil. Furthermore, rADAMTS13 downregulated tPA-induced phosphorylation of Akt and activation of RhoA. INTERPRETATION These findings demonstrate that the VWF-cleaving protease rADAMTS13 reduced tPA-induced hemorrhage by regulating BBB integrity, and suggest that this effect may occur through the Akt/RhoA-mediated VEGF pathways.
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Affiliation(s)
- Lixiang Wang
- State Key Laboratory of Medical Neurobiology, Shanghai Medical College and Institutes of Brain Science, Fudan University, Shanghai, China
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