1
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Woo KM, Mahrous MA, D'Amico DJ, Kiss S, Kovacs KD. Prevalence of Age-Related Macular Degeneration in Patients with Chronic Exposure to P2X7R Inhibitors. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06507-9. [PMID: 38761206 DOI: 10.1007/s00417-024-06507-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/11/2024] [Accepted: 05/02/2024] [Indexed: 05/20/2024] Open
Abstract
PURPOSE P2X7 receptor (P2X7R) is a purinergic cation channel whose activation has been linked with age-related macular degeneration (ARMD). Several nucleoside reverse transcriptase inhibitors, zidovudine (AZT), lamivudine (3TC) and abacavir (ABC), have been shown to inhibit P2X7R and improve outcomes in animal models of ARMD. Our aim is to investigate the association between chronic AZT, 3TC, and ABC therapy and ARMD in a clinical setting. METHODS This is a retrospective cohort study comparing 445 patients with HIV and confirmed usage of AZT, 3TC, and ABC against 200 patients with HIV without usage of AZT, 3TC, and ABC and 445 non-HIV infected patients. Fundus examination and spectral domain optical coherence tomography (SD-ODT) were used to measure prevalence of early-intermediate stage ARMD, geographic atrophy, and exudative ARMD. RESULTS There was no statistically significant difference in the prevalence of early-intermediate stage ARMD between the HIV infected patients with a history of AZT, 3TC, and ABC use and the HIV infected patients without AZT, 3TC, and ABC use (p = 0.887). There was also no statistically significant difference in the prevalence of geographical atrophy (p = 0.062) and exudative AMD (p > 0.999) between the HIV infected patients with a history of AZT, 3TC, and ABC use and non-HIV infected patients. CONCLUSION We did not find an effect of P2X7R inhibiting antiretrovirals usage on early-intermediate stage ARMD, geographical atrophy, or exudative ARMD. Studies with larger cohort and more rigorous medication history are needed to assess the effects on geographical atrophy or exudative ARMD.
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Affiliation(s)
- Kwang Min Woo
- Department of Ophthalmology, Weill Cornell Medical College, 1305 York Avenue, 11Th Floor, New York, NY, 10021, USA
| | - M Abdallah Mahrous
- Department of Ophthalmology, Weill Cornell Medical College, 1305 York Avenue, 11Th Floor, New York, NY, 10021, USA
| | - Donald J D'Amico
- Department of Ophthalmology, Weill Cornell Medical College, 1305 York Avenue, 11Th Floor, New York, NY, 10021, USA
| | - Szilard Kiss
- Department of Ophthalmology, Weill Cornell Medical College, 1305 York Avenue, 11Th Floor, New York, NY, 10021, USA
| | - Kyle D Kovacs
- Department of Ophthalmology, Weill Cornell Medical College, 1305 York Avenue, 11Th Floor, New York, NY, 10021, USA.
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2
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Korhonen E. Inflammasome activation in response to aberrations of cellular homeostasis in epithelial cells from human cornea and retina. Acta Ophthalmol 2024; 102 Suppl 281:3-68. [PMID: 38386419 DOI: 10.1111/aos.16646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 01/16/2024] [Indexed: 02/24/2024]
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3
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Olivier E, Rat P. Role of Oxysterols in Ocular Degeneration Mechanisms and Involvement of P2X7 Receptor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:277-292. [PMID: 38036885 DOI: 10.1007/978-3-031-43883-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Ocular degeneration, including cataracts, glaucoma, macular degeneration, and diabetic retinopathy, is a major public health challenge, as it affects the quality of life of millions of people worldwide and, in its advanced stages, leads to blindness. Ocular degeneration, although it can affect different parts of the eye, shares common characteristics such as oxysterols and the P2X7 receptor. Indeed, oxysterols, which are cholesterol derivatives, are associated with ocular degeneration pathogenesis and trigger inflammation and cell death pathways. Activation of the P2X7 receptor is also linked to ocular degeneration and triggers the same pathways. In age-related macular degeneration, these two key players have been associated, but further studies are needed to extrapolate this interrelationship to other ocular degenerations.
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Affiliation(s)
| | - Patrice Rat
- Université Paris Cité, CNRS, CiTCoM, Paris, France
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4
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Fan Q, Li H, Wang X, Tham YC, Teo KYC, Yasuda M, Lim WK, Kwan YP, Teo JX, Chen CJ, Chen LJ, Ahn J, Davila S, Miyake M, Tan P, Park KH, Pang CP, Khor CC, Wong TY, Yanagi Y, Cheung CMG, Cheng CY. Contribution of common and rare variants to Asian neovascular age-related macular degeneration subtypes. Nat Commun 2023; 14:5574. [PMID: 37696869 PMCID: PMC10495468 DOI: 10.1038/s41467-023-41256-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 08/28/2023] [Indexed: 09/13/2023] Open
Abstract
Neovascular age-related macular degeneration (nAMD), along with its clinical subtype known as polypoidal choroidal vasculopathy (PCV), are among the leading causes of vision loss in elderly Asians. In a genome-wide association study (GWAS) comprising 3,128 nAMD (1,555 PCV and 1,573 typical nAMD), and 5,493 controls of East Asian ancestry, we identify twelve loci, of which four are novel ([Formula: see text]). Substantial genetic sharing between PCV and typical nAMD is noted (rg = 0.666), whereas collagen extracellular matrix and fibrosis-related pathways are more pronounced for PCV. Whole-exome sequencing in 259 PCV patients revealed functional rare variants burden in collagen type I alpha 1 chain gene (COL1A1; [Formula: see text]) and potential enrichment of functional rare mutations at AMD-associated loci. At the GATA binding protein 5 (GATA5) locus, the most significant GWAS novel loci, the expressions of genes including laminin subunit alpha 5 (Lama5), mitochondrial ribosome associated GTPase 2 (Mtg2), and collagen type IX alpha 3 chain (Col9A3), are significantly induced during retinal angiogenesis and subretinal fibrosis in murine models. Furthermore, retinoic acid increased the expression of LAMA5 and MTG2 in vitro. Taken together, our data provide insights into the genetic basis of AMD pathogenesis in the Asian population.
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Affiliation(s)
- Qiao Fan
- Center for Quantitative Medicine, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore.
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore.
| | - Hengtong Li
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Centre for Innovation and Precision Eye Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xiaomeng Wang
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore
- Center for Vision Research, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Yih-Chung Tham
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Centre for Innovation and Precision Eye Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Kelvin Yi Chong Teo
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Masayuki Yasuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Weng Khong Lim
- SingHealth Duke-NUS Institute of Precision Medicine, Singapore, Singapore
- SingHealth Duke-NUS Genomic Medicine Centre, Singapore, Singapore
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore, Singapore
- Laboratory of Genome Variation Analytics, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Yuet Ping Kwan
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore
| | - Jing Xian Teo
- SingHealth Duke-NUS Institute of Precision Medicine, Singapore, Singapore
| | - Ching-Jou Chen
- Center for Vision Research, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jeeyun Ahn
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea
| | - Sonia Davila
- SingHealth Duke-NUS Institute of Precision Medicine, Singapore, Singapore
| | - Masahiro Miyake
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Patrick Tan
- SingHealth Duke-NUS Institute of Precision Medicine, Singapore, Singapore
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore, Singapore
- Human Genetics, Genome Institute of Singapore, Singapore, Singapore
| | - Kyu Hyung Park
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Chiea Chuan Khor
- Human Genetics, Genome Institute of Singapore, Singapore, Singapore
| | - Tien Yin Wong
- Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Yasuo Yanagi
- Department of Ophthalmology and Microtechnology, Yokohama City University, Yokohama, Japan
| | - Chui Ming Gemmy Cheung
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Ching-Yu Cheng
- Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore.
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Centre for Innovation and Precision Eye Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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5
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Molcak H, Jiang K, Campbell CJ, Matsubara JA. Purinergic signaling via P2X receptors and mechanisms of unregulated ATP release in the outer retina and age-related macular degeneration. Front Neurosci 2023; 17:1216489. [PMID: 37496736 PMCID: PMC10366617 DOI: 10.3389/fnins.2023.1216489] [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: 05/03/2023] [Accepted: 06/26/2023] [Indexed: 07/28/2023] Open
Abstract
Age-related macular degeneration (AMD) is a chronic and progressive inflammatory disease of the retina characterized by photoceptor loss and significant central visual impairment due to either choroidal neovascularization or geographic atrophy. The pathophysiology of AMD is complex and multifactorial, driven by a combination of modifiable and non-modifiable risk factors, molecular mechanisms, and cellular processes that contribute to overall disease onset, severity, and progression. Unfortunately, due to the structural, cellular, and pathophysiologic complexity, therapeutic discovery is challenging. While purinergic signaling has been investigated for its role in the development and treatment of ocular pathologies including AMD, the potential crosstalk between known contributors to AMD, such as the complement cascade and inflammasome activation, and other biological systems, such as purinergic signaling, have not been fully characterized. In this review, we explore the interactions between purinergic signaling, ATP release, and known contributors to AMD pathogenesis including complement dysregulation and inflammasome activation. We begin by identifying what is known about purinergic receptors in cell populations of the outer retina and potential sources of extracellular ATP required to trigger purinergic receptor activation. Next, we examine evidence in the literature that the purinergic system accelerates AMD pathogenesis leading to apoptotic and pyroptotic cell death in retinal cells. To fully understand the potential role that purinergic signaling plays in AMD, more research is needed surrounding the expression, distribution, functions, and interactions of purinergic receptors within cells of the outer retina as well as potential crosstalk with other systems. By determining how these processes are affected in the context of purinergic signaling, it will improve our understanding of the mechanisms that drive AMD pathogenesis which is critical in developing treatment strategies that prevent or slow progression of the disease.
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Affiliation(s)
- Haydn Molcak
- Matsubara Lab, Faculty of Medicine, Department of Ophthalmology and Visual Sciences, Eye Care Centre, Vancouver, BC, Canada
| | - Kailun Jiang
- Matsubara Lab, Faculty of Medicine, Department of Ophthalmology and Visual Sciences, Eye Care Centre, Vancouver, BC, Canada
| | | | - Joanne A. Matsubara
- Matsubara Lab, Faculty of Medicine, Department of Ophthalmology and Visual Sciences, Eye Care Centre, Vancouver, BC, Canada
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6
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Markitantova Y, Simirskii V. Endogenous and Exogenous Regulation of Redox Homeostasis in Retinal Pigment Epithelium Cells: An Updated Antioxidant Perspective. Int J Mol Sci 2023; 24:10776. [PMID: 37445953 DOI: 10.3390/ijms241310776] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
The retinal pigment epithelium (RPE) performs a range of necessary functions within the neural layers of the retina and helps ensure vision. The regulation of pro-oxidative and antioxidant processes is the basis for maintaining RPE homeostasis and preventing retinal degenerative processes. Long-term stable changes in the redox balance under the influence of endogenous or exogenous factors can lead to oxidative stress (OS) and the development of a number of retinal pathologies associated with RPE dysfunction, and can eventually lead to vision loss. Reparative autophagy, ubiquitin-proteasome utilization, the repair of damaged proteins, and the maintenance of their conformational structure are important interrelated mechanisms of the endogenous defense system that protects against oxidative damage. Antioxidant protection of RPE cells is realized as a result of the activity of specific transcription factors, a large group of enzymes, chaperone proteins, etc., which form many signaling pathways in the RPE and the retina. Here, we discuss the role of the key components of the antioxidant defense system (ADS) in the cellular response of the RPE against OS. Understanding the role and interactions of OS mediators and the components of the ADS contributes to the formation of ideas about the subtle mechanisms in the regulation of RPE cellular functions and prospects for experimental approaches to restore RPE functions.
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Affiliation(s)
- Yuliya Markitantova
- Koltsov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Vladimir Simirskii
- Koltsov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
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7
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P2X7 Is Involved in the Mouse Retinal Degeneration via the Coordinated Actions in Different Retinal Cell Types. Antioxidants (Basel) 2023; 12:antiox12010141. [PMID: 36671003 PMCID: PMC9854982 DOI: 10.3390/antiox12010141] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Adenosine triphosphate (ATP) released from dying cells with high concentrations is sensed as a danger signal by the P2X7 receptor. Sodium iodate (NaIO3) is an oxidative toxic agent, and its retinal toxicity has been used as the model of dry age-related macular degeneration (AMD). In this study, we used NaIO3-treated mice and cultured retinal cells, including BV-2 microglia, 661W photoreceptors, rMC1 Müller cells and ARPE-19 retinal epithelial cells, to understand the pathological action of P2X7 in retinal degeneration. We found that NaIO3 can significantly decrease the photoreceptor function by reducing a-wave and b-wave amplitudes in electroretinogram (ERG) analysis. Optical coherence tomography (OCT) analysis revealed the degeneration of retinal epithelium and ganglion cell layers. Interestingly, P2X7-/- mice were protected from the NaIO3-induced retinopathy and inflammatory NLRP3, IL-1β and IL-6 gene expression in the retina. Hematoxylin and eosin staining indicated that the retinal epithelium was less deteriorated in P2X7-/- mice compared to the WT group. Although P2X7 was barely detected in 661W, rMC1 and ARPE-19 cells, its gene and protein levels can be increased after NaIO3 treatment, leading to a synergistic cytotoxicity of BzATP [2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate tri(triethyleneammonium)salt] and NaIO3 administration in ARPE-19 cells. In conclusion, the paracrine action of the ATP/P2X7 axis via cell-cell communication is involved in NaIO3-induced retinal injury. Our results show that P2X7 antagonist might be a potential therapy in inflammation-related retinal degeneration.
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8
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Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
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9
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Ye SS, Tang Y, Song JT. ATP and Adenosine in the Retina and Retinal Diseases. Front Pharmacol 2021; 12:654445. [PMID: 34211393 PMCID: PMC8239296 DOI: 10.3389/fphar.2021.654445] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 05/25/2021] [Indexed: 12/11/2022] Open
Abstract
Extracellular ATP and its ultimate degradation product adenosine are potent extracellular signaling molecules that elicit a variety of pathophysiological pathways in retina through the activation of P2 and P1 purinoceptors, respectively. Excessive build-up of extracellular ATP accelerates pathologic responses in retinal diseases, whereas accumulation of adenosine protects retinal cells against degeneration or inflammation. This mini-review focuses on the roles of ATP and adenosine in three types of blinding diseases including age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy (DR). Several agonists and antagonists of ATP receptors and adenosine receptors (ARs) have been developed for the potential treatment of glaucoma, DR and AMD: antagonists of P2X7 receptor (P2X7R) (BBG, MRS2540) prevent ATP-induced neuronal apoptosis in glaucoma, DR, and AMD; A1 receptor (A1R) agonists (INO-8875) lower intraocular pressure in glaucoma; A2A receptor (A2AR) agonists (CGS21680) or antagonists (SCH58261, ZM241385) reduce neuroinflammation in glaucoma, DR, and AMD; A3 receptor (A3R) agonists (2-Cl-lB-MECA, MRS3558) protect retinal ganglion cells (RGCs) from apoptosis in glaucoma.
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Affiliation(s)
- Shan-Shan Ye
- Eye Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yong Tang
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Jian-Tao Song
- Eye Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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10
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Differential Action of Connexin Hemichannel and Pannexin Channel Therapeutics for Potential Treatment of Retinal Diseases. Int J Mol Sci 2021; 22:ijms22041755. [PMID: 33578721 PMCID: PMC7916454 DOI: 10.3390/ijms22041755] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/02/2021] [Accepted: 02/07/2021] [Indexed: 12/15/2022] Open
Abstract
Dysregulation of retinal function in the early stages of light-induced retinal degeneration involves pannexins and connexins. These two types of proteins may contribute to channels that release ATP, leading to activation of the inflammasome pathway, spread of inflammation and retinal dysfunction. However, the effect of pannexin channel block alone or block of both pannexin channels and connexin hemichannels in parallel on retinal activity in vivo is unknown. In this study, the pannexin channel blocker probenecid and the connexin hemichannel blocker tonabersat were used in the light-damaged rat retina. Retinal function was evaluated using electroretinography (ERG), retinal structure was analyzed using optical coherence tomography (OCT) imaging and the tissue response to light-induced injury was assessed immunohistochemically with antibodies against glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1 (Iba-1) and Connexin43 (Cx43). Probenecid did not further enhance the therapeutic effect of connexin hemichannel block in this model, but on its own improved activity of certain inner retina neurons. The therapeutic benefit of blocking connexin hemichannels was further evaluated by comparing these data against results from our previously published studies that also used the light-damaged rat retina model. The analysis showed that treatment with tonabersat alone was better than probenecid alone at restoring retinal function in the light-damaged retina model. The results assist in the interpretation of the differential action of connexin hemichannel and pannexin channel therapeutics for potential treatment of retinal diseases.
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11
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Shao X, Guha S, Lu W, Campagno KE, Beckel JM, Mills JA, Yang W, Mitchell CH. Polarized Cytokine Release Triggered by P2X7 Receptor from Retinal Pigmented Epithelial Cells Dependent on Calcium Influx. Cells 2020; 9:cells9122537. [PMID: 33255431 PMCID: PMC7760537 DOI: 10.3390/cells9122537] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022] Open
Abstract
Cytokine release from non-inflammatory cells is a key step in innate immunity, and agonists triggering cytokine release are central in coordinating responses. P2X7 receptor (P2X7R) stimulation by extracellular ATP is best known to active the NLRP3 inflammasome and release IL-1β, but stimulation also leads to release of other cytokines. As cytokine signaling by retinal pigmented epithelial (RPE) cells is implicated in retinal neurodegeneration, the role of P2X7R in release of cytokine IL-6 from RPE cells was investigated. P2X7R stimulation triggered IL-6 release from primary mouse RPE, human iPS-RPE and human ARPE-19 cells. IL-6 release was polarized, with predominant rise across apical membranes. IL-6 release was inhibited by P2X7R antagonists A438079, A839977, and AZ10606120, but not the NRTI lamivudine (3TC), P2X1R antagonist NF279, or P2Y1R antagonist MRS2179. P2X7R-mediated IL-6 release required extracellular Ca2+ and was blocked by Ca2+ chelator BAPTA. IL-6 release and Ca2+ elevation occurred rapidly, consistent with vesicular IL-6 staining in unstimulated cells. P2X7R stimulation did not trigger IL-1β release in these unprimed cells. P2X7R-mediated IL-6 release was enhanced in RPE cells from the ABCA4−/− mouse model of retinal degeneration. In summary, P2X7R stimulation triggers rapid Ca2+-dependent IL-6 release across the apical membrane of RPE cells.
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Affiliation(s)
- Xiaolei Shao
- Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen 518060, China;
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
| | - Sonia Guha
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Wennan Lu
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
| | - Keith E. Campagno
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
| | - Jonathan M. Beckel
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jason A. Mills
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wenli Yang
- Department of Medicine and Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Claire H. Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Correspondence: ; Tel.: +1-215-573-2176
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12
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Calzaferri F, Ruiz-Ruiz C, de Diego AMG, de Pascual R, Méndez-López I, Cano-Abad MF, Maneu V, de Los Ríos C, Gandía L, García AG. The purinergic P2X7 receptor as a potential drug target to combat neuroinflammation in neurodegenerative diseases. Med Res Rev 2020; 40:2427-2465. [PMID: 32677086 DOI: 10.1002/med.21710] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 06/22/2020] [Accepted: 06/27/2020] [Indexed: 12/25/2022]
Abstract
Neurodegenerative diseases (NDDs) represent a huge social burden, particularly in Alzheimer's disease (AD) in which all proposed treatments investigated in murine models have failed during clinical trials (CTs). Thus, novel therapeutic strategies remain crucial. Neuroinflammation is a common pathogenic feature of NDDs. As purinergic P2X7 receptors (P2X7Rs) are gatekeepers of inflammation, they could be developed as drug targets for NDDs. Herein, we review this challenging hypothesis and comment on the numerous studies that have investigated P2X7Rs, emphasizing their molecular structure and functions, as well as their role in inflammation. Then, we elaborate on research undertaken in the field of medicinal chemistry to determine potential P2X7R antagonists. Subsequently, we review the state of neuroinflammation and P2X7R expression in the brain, in animal models and patients suffering from AD, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and retinal degeneration. Next, we summarize the in vivo studies testing the hypothesis that by mitigating neuroinflammation, P2X7R blockers afford neuroprotection, increasing neuroplasticity and neuronal repair in animal models of NDDs. Finally, we reviewed previous and ongoing CTs investigating compounds directed toward targets associated with NDDs; we propose that CTs with P2X7R antagonists should be initiated. Despite the high expectations for putative P2X7Rs antagonists in various central nervous system diseases, the field is moving forward at a relatively slow pace, presumably due to the complexity of P2X7Rs. A better pharmacological approach to combat NDDs would be a dual strategy, combining P2X7R antagonism with drugs targeting a selective pathway in a given NDD.
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Affiliation(s)
- Francesco Calzaferri
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristina Ruiz-Ruiz
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio M G de Diego
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ricardo de Pascual
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iago Méndez-López
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - María F Cano-Abad
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Cristóbal de Los Ríos
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luis Gandía
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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13
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Linetsky M, Guo J, Udeigwe E, Ma D, Chamberlain AS, Yu AO, Solovyova K, Edgar E, Salomon RG. 4-Hydroxy-7-oxo-5-heptenoic acid (HOHA) lactone induces apoptosis in retinal pigment epithelial cells. Free Radic Biol Med 2020; 152:280-294. [PMID: 32222470 PMCID: PMC7276294 DOI: 10.1016/j.freeradbiomed.2020.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 03/23/2020] [Accepted: 03/23/2020] [Indexed: 02/06/2023]
Abstract
Retinal pigment epithelial (RPE) cell dysfunction and death play vital roles in age-related macular degeneration (AMD) pathogenesis. Previously we showed that oxidative cleavage of docosahexenoate (DHA) phospholipids generates an α,β-unsaturated aldehyde, 4-hydroxy-7-oxohept-4-enoic acid (HOHA) lactone, that forms ω-carboxyethylpyrrole (CEP) derivatives through adduction to proteins and ethanolamine phospholipids. CEP derivatives and autoantibodies accumulate in the retinas and blood plasma of individuals with AMD and are a biomarker of AMD. They promote the choroidal neovascularization of "wet AMD". Immunization of mice with CEP-modified mouse serum albumin induces "dry AMD"-like lesions in their retinas as well as interferon-gamma and interleukin-17 production by CEP-specific T cells that promote inflammatory M1 polarization of macrophages. The present study confirms that oxidative stress or inflammatory stimulus produces CEP in both the primary human ARPE-19 cell line and hRPE cells. Exposure of these cells to HOHA lactone fosters production of reactive oxygen species. Thus, HOHA lactone participates in a vicious cycle, promoting intracellular oxidative stress leading to oxidative cleavage of DHA to produce more HOHA lactone. We now show that HOHA lactone is cytotoxic, inducing apoptotic cell death through activation of the intrinsic pathway. This suggests that therapeutic interventions targeting HOHA lactone-induced apoptosis may prevent the loss of RPE cells during the early phase of AMD. We also discovered that ARPE-19 cells are more susceptible than hRPE cells to HOHA lactone cytotoxicity. This is consistent with the view that, compared to normal RPE cells, ARPE-19 cells exhibit a diseased RPE phenotype that also includes elevated expression of the mesenchymal indicator vimentin, elevated integrin a5 promotor strength and deficient secretion of the anti-VEGF molecule pigment-epithelium-derived factor fostering weaker tight junctions.
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Affiliation(s)
- Mikhail Linetsky
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Ophthalmology and Visual Sciences, Case Western Reserve University, USA
| | - Junhong Guo
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Emeka Udeigwe
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Duoming Ma
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Amanda S Chamberlain
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Annabelle O Yu
- Department of Biology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Kseniya Solovyova
- Department of Chemistry, Cleveland State University, Cleveland, OH, 44115, USA
| | - Elise Edgar
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Robert G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Ophthalmology and Visual Sciences, Case Western Reserve University, USA.
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14
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Medrano MP, Pisera-Fuster A, Bernabeu RO, Faillace MP. P2X7 and A 2A receptor endogenous activation protects against neuronal death caused by CoCl 2 -induced photoreceptor toxicity in the zebrafish retina. J Comp Neurol 2020; 528:2000-2020. [PMID: 31997350 DOI: 10.1002/cne.24869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 01/09/2020] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
Injured retinas in mammals do not regenerate and heal with loss of function. The adult retina of zebrafish self-repairs after damage by activating cell-intrinsic mechanisms, which are regulated by extrinsic signal interactions. Among relevant regulatory extrinsic systems, purinergic signaling regulates progenitor proliferation during retinogenesis and regeneration and glia proliferation in proliferative retinopathies. ATP-activated P2X7 (P2RX7) and adenosine (P1R) receptors are involved in the progression of almost all retinopathies leading to blindness. Here, we examined P2RX7 and P1R participation in the retina regenerative response induced by photoreceptor damage caused by a specific dose of CoCl2 . First, we found that treatment of uninjured retinas with a potent agonist of P2RX7 (BzATP) provoked photoreceptor damage and mitotic activation of multipotent progenitors. In CoCl2 -injured retinas, blockade of endogenous extracellular ATP activity on P2RX7 caused further neurodegeneration, Müller cell gliosis, progenitor proliferation, and microglia reactivity. P2RX7 inhibition in injured retinas also increased the expression of lin28a and tnfα genes, which are related to multipotent progenitor proliferation. Levels of hif1α, vegf3r, and vegfaa mRNA were enhanced by blockade of P2RX7 immediately after injury, indicating hypoxic like damage and endothelial cell growth and proliferation. Complete depletion of extracellular nucleotides with an apyrase treatment strongly potentiated cell death and progenitor proliferation induced with CoCl2 . Blockade of adenosine P1 and A2A receptors (A2A R) had deleterious effects and deregulated normal timing for progenitor and precursor cell proliferation following photoreceptor damage. ATP via P2RX7 and adenosine via A2A R are survival extracellular signals key for retina regeneration in zebrafish.
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Affiliation(s)
- Matías P Medrano
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Antonella Pisera-Fuster
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Ramón O Bernabeu
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - María Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
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15
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Laíns I, Chung W, Kelly RS, Gil J, Marques M, Barreto P, Murta JN, Kim IK, Vavvas DG, Miller JB, Silva R, Lasky-Su J, Liang L, Miller JW, Husain D. Human Plasma Metabolomics in Age-Related Macular Degeneration: Meta-Analysis of Two Cohorts. Metabolites 2019; 9:E127. [PMID: 31269701 PMCID: PMC6680405 DOI: 10.3390/metabo9070127] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 01/01/2023] Open
Abstract
The pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness worldwide, remains only partially understood. This has led to the current lack of accessible and reliable biofluid biomarkers for diagnosis and prognosis, and absence of treatments for dry AMD. This study aimed to assess the plasma metabolomic profiles of AMD and its severity stages with the ultimate goal of contributing to addressing these needs. We recruited two cohorts: Boston, United States (n = 196) and Coimbra, Portugal (n = 295). Fasting blood samples were analyzed using ultra-high performance liquid chromatography mass spectrometry. For each cohort, we compared plasma metabolites of AMD patients versus controls (logistic regression), and across disease stages (permutation-based cumulative logistic regression considering both eyes). Meta-analyses were then used to combine results from the two cohorts. Our results revealed that 28 metabolites differed significantly between AMD patients versus controls (false discovery rate (FDR) q-value: 4.1 × 10-2-1.8 × 10-5), and 67 across disease stages (FDR q-value: 4.5 × 10-2-1.7 × 10-4). Pathway analysis showed significant enrichment of glycerophospholipid, purine, taurine and hypotaurine, and nitrogen metabolism (p-value ≤ 0.04). In conclusion, our findings support that AMD patients present distinct plasma metabolomic profiles, which vary with disease severity. This work contributes to the understanding of AMD pathophysiology, and can be the basis of future biomarkers and precision medicine for this blinding condition.
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Affiliation(s)
- Inês Laíns
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Wonil Chung
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Rachel S Kelly
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - João Gil
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
| | - Marco Marques
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
| | - Patrícia Barreto
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Joaquim N Murta
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Ivana K Kim
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Demetrios G Vavvas
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - John B Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Rufino Silva
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Jessica Lasky-Su
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Liming Liang
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Joan W Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Deeba Husain
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
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16
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Akhtar-Schäfer I, Wang L, Krohne TU, Xu H, Langmann T. Modulation of three key innate immune pathways for the most common retinal degenerative diseases. EMBO Mol Med 2019; 10:emmm.201708259. [PMID: 30224384 PMCID: PMC6180304 DOI: 10.15252/emmm.201708259] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This review highlights the role of three key immune pathways in the pathophysiology of major retinal degenerative diseases including diabetic retinopathy, age‐related macular degeneration, and rare retinal dystrophies. We first discuss the mechanisms how loss of retinal homeostasis evokes an unbalanced retinal immune reaction involving responses of local microglia and recruited macrophages, activity of the alternative complement system, and inflammasome assembly in the retinal pigment epithelium. Presenting these key mechanisms as complementary targets, we specifically emphasize the concept of immunomodulation as potential treatment strategy to prevent or delay vision loss. Promising molecules are ligands for phagocyte receptors, specific inhibitors of complement activation products, and inflammasome inhibitors. We comprehensively summarize the scientific evidence for this strategy from preclinical animal models, human ocular tissue analyses, and clinical trials evolving in the last few years.
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Affiliation(s)
- Isha Akhtar-Schäfer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Luping Wang
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Tim U Krohne
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Heping Xu
- Centre for Experimental Medicine, The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany .,Center for Molecular Medicine, University of Cologne, Cologne, Germany
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17
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An improved method for isolation of mitochondria from cell lines that enables reconstitution of calcium-dependent processes. Anal Biochem 2019; 577:52-58. [PMID: 31022379 DOI: 10.1016/j.ab.2019.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/11/2019] [Accepted: 04/16/2019] [Indexed: 01/15/2023]
Abstract
Optimum cytosolic calcium concentrations support balanced mitochondrial respiration. However, cytosolic Ca2+ concentrations vary among cell types and excess Ca2+ can cause mitochondrial dysfunction. We optimized an isolation protocol to eliminate excess Ca2+ and thereby minimizing structural damage. Ca2+ uptake was monitored by measuring mitochondrial Ca2+-dependent PKA activity using cAMP ELISAs, and O2 consumption levels during mitochondrial respiration using high-resolution respirometry. 3 nM Ca2+ was found to increase cAMP levels and produce optimal state III respiration. Hence, optimized isolation of mitochondria from cell lines using calcium denudation provides the best platform for the study of Ca2+-dependent regulation of mitochondrial signaling.
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18
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Wang L, Schmidt S, Larsen PP, Meyer JH, Roush WR, Latz E, Holz FG, Krohne TU. Efficacy of novel selective NLRP3 inhibitors in human and murine retinal pigment epithelial cells. J Mol Med (Berl) 2019; 97:523-532. [DOI: 10.1007/s00109-019-01753-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/10/2019] [Accepted: 01/29/2019] [Indexed: 12/28/2022]
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19
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Sakamoto K, Inukai M, Mori A, Nakahara T. Brilliant Blue G protects against photoreceptor injury in a murine endotoxin-induced uveitis model. Exp Eye Res 2018; 177:45-49. [DOI: 10.1016/j.exer.2018.07.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/11/2018] [Accepted: 07/27/2018] [Indexed: 01/09/2023]
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20
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Ventura ALM, Dos Santos-Rodrigues A, Mitchell CH, Faillace MP. Purinergic signaling in the retina: From development to disease. Brain Res Bull 2018; 151:92-108. [PMID: 30458250 DOI: 10.1016/j.brainresbull.2018.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/14/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023]
Abstract
Retinal injuries and diseases are major causes of human disability involving vision impairment by the progressive and permanent loss of retinal neurons. During development, assembly of this tissue entails a successive and overlapping, signal-regulated engagement of complex events that include proliferation of progenitors, neurogenesis, cell death, neurochemical differentiation and synaptogenesis. During retinal damage, several of these events are re-activated with both protective and detrimental consequences. Purines and pyrimidines, along with their metabolites are emerging as important molecules regulating both retinal development and the tissue's responses to damage. The present review provides an overview of the purinergic signaling in the developing and injured retina. Recent findings on the presence of vesicular and channel-mediated ATP release by retinal and retinal pigment epithelial cells, adenosine synthesis and release, expression of receptors and intracellular signaling pathways activated by purinergic signaling in retinal cells are reported. The pathways by which purinergic receptors modulate retinal cell proliferation, migration and death of retinal cells during development and injury are summarized. The contribution of nucleotides to the self-repair of the injured zebrafish retina is also discussed.
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Affiliation(s)
- Ana Lucia Marques Ventura
- Department of Neurobiology, Neuroscience Program, Fluminense Federal University, Niterói, RJ, Brazil.
| | | | - Claire H Mitchell
- Department of Anatomy and Cell Biology, Ophthalmology, and Physiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Maria Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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21
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Light-induced generation and toxicity of docosahexaenoate-derived oxidation products in retinal pigmented epithelial cells. Exp Eye Res 2018; 181:325-345. [PMID: 30296412 DOI: 10.1016/j.exer.2018.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 09/21/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022]
Abstract
Oxidative cleavage of docosahexaenoate (DHA) in retinal pigmented epithelial (RPE) cells produces 4-hydroxy-7-oxohept-5-enoic acid (HOHA) esters of 2-lysophosphatidylcholine (PC). HOHA-PC spontaneously releases a membrane-permeant HOHA lactone that modifies primary amino groups of proteins and ethanolamine phospholipids to produce 2-(ω-carboxyethyl)pyrrole (CEP) derivatives. CEPs have significant pathological relevance to age-related macular degeneration (AMD) including activation of CEP-specific T-cells leading to inflammatory M1 polarization of macrophages in the retina involved in "dry AMD" and TLR2-dependent induction of angiogenesis that characterizes "wet AMD". RPE cells accumulate DHA from shed rod photoreceptor outer segments through phagocytosis and from plasma lipoproteins secreted by the liver through active uptake from the choriocapillaris. As a cell model of light-induced oxidative damage of DHA phospholipids in RPE cells, ARPE-19 cells were supplemented with DHA, with or without the lipofuscin fluorophore A2E. In this model, light exposure, in the absence of A2E, promoted the generation HOHA lactone-glutathione (GSH) adducts, depletion of intracellular GSH and a competing generation of CEPs. While DHA-rich RPE cells exhibit an inherent proclivity toward light-induced oxidative damage, photosensitization by A2E nearly doubled the amount of lipid oxidation and expanded the spectral range of photosensitivity to longer wavelengths. Exposure of ARPE-19 cells to 1 μM HOHA lactone for 24 h induced massive (50%) loss of lysosomal membrane integrity and caused loss of mitochondrial membrane potential. Using senescence-associated β-galactosidase (SA β-gal) staining that detects lysosomal β-galactosidase, we determined that exposure to HOHA lactone induces senescence in ARPE-19 cells. The present study shows that products of light-induced oxidative damage of DHA phospholipids in the absence of A2E can lead to RPE cell dysfunction. Therefore, their toxicity may be especially important in the early stages of AMD before RPE cells accumulate lipofuscin fluorophores.
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22
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Pasovic L, Utheim TP, Reppe S, Khan AZ, Jackson CJ, Thiede B, Berg JP, Messelt EB, Eidet JR. Improvement of Storage Medium for Cultured Human Retinal Pigment Epithelial Cells Using Factorial Design. Sci Rep 2018; 8:5688. [PMID: 29632395 PMCID: PMC5890280 DOI: 10.1038/s41598-018-24121-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 03/26/2018] [Indexed: 12/19/2022] Open
Abstract
Storage of human retinal pigment epithelium (hRPE) can contribute to the advancement of cell-based RPE replacement therapies. The present study aimed to improve the quality of stored hRPE cultures by identifying storage medium additives that, alone or in combination, contribute to enhancing cell viability while preserving morphology and phenotype. hRPE cells were cultured in the presence of the silk protein sericin until pigmentation. Cells were then stored for 10 days in storage medium plus sericin and either one of 46 different additives. Individual effects of each additive on cell viability were assessed using epifluorescence microscopy. Factorial design identified promising additive combinations by extrapolating their individual effects. Supplementing the storage medium with sericin combined with adenosine, L-ascorbic acid and allopurinol resulted in the highest cell viability (98.6 ± 0.5%) after storage for three days, as measured by epifluorescence microscopy. Flow cytometry validated the findings. Proteomics identified 61 upregulated and 65 downregulated proteins in this storage group compared to the unstored control. Transmission electron microscopy demonstrated the presence of melanosomes after storage in the optimized medium. We conclude that the combination of adenosine, L-ascorbic acid, allopurinol and sericin in minimal essential medium preserves RPE pigmentation while maintaining cell viability during storage.
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Affiliation(s)
- L Pasovic
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway. .,Institute of Clinical Medicine, University of Oslo, Oslo, Norway. .,Department of Surgery, Akershus University Hospital, Lørenskog, Norway.
| | - T P Utheim
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway.,Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Department of Ophthalmology, Stavanger University Hospital, Stavanger, Norway.,Department of Clinical Medicine, Faculty of Medicine, University of Bergen, Bergen, Norway.,Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - S Reppe
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - A Z Khan
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - C J Jackson
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway.,Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - B Thiede
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - J P Berg
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - E B Messelt
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - J R Eidet
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
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23
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Purinergic modulation of frog electroretinographic responses: The role of the ionotropic receptor P2X7. Vis Neurosci 2018; 34:E015. [PMID: 28965497 DOI: 10.1017/s0952523817000128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The contribution of the purinergic receptors P2X7 (P2X7Rs) to the electroretinographic (ERG) responses was studied by testing the effects of the selective P2X7R antagonist A438079 and the selective P2X7R agonist Bz-ATP on the electroretinograms obtained in perfused frog (Rana ridibunda) eyecup preparations under a variety of stimulation conditions. The P2X7R blockade by 200 µM A438079 diminished the amplitude of the photoreceptor components: the a-wave and the pharmacologically isolated mass receptor potential. In the pure rod-driven and pure cone-driven responses, the amplitude of the postreceptoral ON (b-wave) and OFF (d-wave) components was also diminished. The OFF responses were affected to a greater extent compared to the ON responses. In the mixed rod- and cone-driven responses, obtained in the mesopic intensity range, the b-wave amplitude was increased, while the d-wave amplitude was decreased. The amplitude of the oscillatory potentials was diminished. The relative amplitude changes produced by the P2X7R blockade were greater in the dark-adapted compared to the light-adapted eyes. The application of 100 µM Bz-ATP produced small effects opposite to those of the antagonist, while a prolonged (>20 min) treatment with 1 mM Bz-ATP resulted in a significant amplitude reduction or even abolishment of b- and d-waves. Our results show that endogenous ATP through its P2X7Rs exerts significant, mostly potentiating effects on the ERG photoreceptor and postreceptoral responses. There is a clear ON/OFF asymmetry of the effects on the ERG postreceptoral responses favoring OFF responses: they are always strongly potentiated, while the ON responses are either less potentiated (in the rod-driven and most of the cone-driven responses) or even inhibited (in the mixed rod- and cone-driven responses). The overstimulation of P2X7Rs can produce acute pathological changes, that is, a decrease or abolishment of the ERG responses.
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24
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Vessey KA, Gu BJ, Jobling AI, Phipps JA, Greferath U, Tran MX, Dixon MA, Baird PN, Guymer RH, Wiley JS, Fletcher EL. Loss of Function of P2X7 Receptor Scavenger Activity in Aging Mice: A Novel Model for Investigating the Early Pathogenesis of Age-Related Macular Degeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2017. [PMID: 28628761 DOI: 10.1016/j.ajpath.2017.04.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible, severe vision loss in Western countries. Recently, we identified a novel pathway involving P2X7 receptor scavenger function expressed on ocular immune cells as a risk factor for advanced AMD. In this study, we investigate the effect of loss of P2X7 receptor function on retinal structure and function during aging. P2X7-null and wild-type C57bl6J mice were investigated at 4, 12, and 18 months of age for macrophage phagocytosis activity, ocular histological changes, and retinal function. Phagocytosis activity of blood-borne macrophages decreased with age at 18 months in the wild-type mouse. Lack of P2X7 receptor function reduced phagocytosis at all ages compared to wild-type mice. At 12 months of age, P2X7-null mice had thickening of Bruchs membrane and retinal pigment epithelium dysfunction. By 18 months of age, P2X7-null mice displayed phenotypic characteristics consistent with early AMD, including Bruchs membrane thickening, retinal pigment epithelium cell loss, retinal functional deficits, and signs of subretinal inflammation. Our present study shows that loss of function of the P2X7 receptor in mice induces retinal changes representing characteristics of early AMD, providing a valuable model for investigating the role of scavenger receptor function and the immune system in the development of this age-related disease.
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Affiliation(s)
- Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Ben J Gu
- Florey Institute of Neuroscience, Melbourne, Victoria, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Joanna A Phipps
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Mai X Tran
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Michael A Dixon
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul N Baird
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Division of Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Division of Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - James S Wiley
- Florey Institute of Neuroscience, Melbourne, Victoria, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia.
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25
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The Role of the P2X7 Receptor in Ocular Stresses: A Potential Therapeutic Target. Vision (Basel) 2017; 1:vision1020014. [PMID: 31740640 PMCID: PMC6835678 DOI: 10.3390/vision1020014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/10/2017] [Accepted: 05/14/2017] [Indexed: 01/30/2023] Open
Abstract
The P2X7 receptor is expressed in both anterior and posterior segments of the eyeball. In the ocular surface, the P2X7 receptor is activated in case of external aggressions: preservatives and surfactants induce the activation of P2X7 receptors, leading to either apoptosis, inflammation, or cell proliferation. In the retina, the key endogenous actors of age-related macular degeneration, diabetic retinopathy, and glaucoma act through P2X7 receptors’ activation and/or upregulation of P2X7 receptors’ expression. Different therapeutic strategies aimed at the P2X7 receptor exist. P2X7 receptor antagonists, such as divalent cations and Brilliant Blue G (BBG) could be used to target either the ocular surface or the retina, as long as polyunsaturated fatty acids may exert their effects through the disruption of plasma membrane lipid rafts or saffron that reduces the response evoked by P2X7 receptor stimulation. Treatments against P2X7 receptor activation are proposed by using either eye drops or food supplements.
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26
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Wang J, Liu S, Nie Y, Wu B, Wu Q, Song M, Tang M, Xiao L, Xu P, Tan X, Zhang L, Li G, Liang S, Zhang C. Activation of P2X7 receptors decreases the proliferation of murine luteal cells. Reprod Fertil Dev 2017; 27:1262-71. [PMID: 25782073 DOI: 10.1071/rd14381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/09/2015] [Indexed: 12/14/2022] Open
Abstract
Extracellular ATP regulates cellular function in an autocrine or paracrine manner through activating purinergic signalling. Studies have shown that purinergic receptors were expressed in mammalian ovaries and they have been proposed as an intra-ovarian regulatory mechanism. P2X7 was expressed in porcine ovarian theca cells and murine and human ovarian surface epithelium and is involved in ATP-induced apoptotic cell death. However, the role of P2X7 in corpus luteum is still unclear. The aim of this study was to investigate the role of ATP signalling in murine luteal cells and the possible mechanism(s) involved. We found that P2X7 was highly expressed in murine small luteal cells. The agonists of P2X7, ATP and BzATP, inhibited the proliferation of luteal cells. P2X7 antagonist BBG reversed the inhibition induced by ATP and BzATP. Further studies showed that ATP and BzATP inhibited the expression of cell cycle regulators cyclinD2 and cyclinE2. ATP and BzATP also inhibited the p38-mitogen-activated protein kinase (MAPK) signalling pathway. These results reveal that P2X7 receptor activation is involved in corpus luteum formation and function.
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Affiliation(s)
- Jing Wang
- Department of Microbiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shuangmei Liu
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Yijun Nie
- The First Affiliated Hospital, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Bing Wu
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Qin Wu
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Miaomiao Song
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Min Tang
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Li Xiao
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Ping Xu
- School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Ximin Tan
- School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Luyin Zhang
- School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Gang Li
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shangdong Liang
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Chunping Zhang
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
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27
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Targeting the P2X7 Receptor in Age-Related Macular Degeneration. Vision (Basel) 2017; 1:vision1020011. [PMID: 31740637 PMCID: PMC6836166 DOI: 10.3390/vision1020011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 03/30/2017] [Accepted: 03/30/2017] [Indexed: 01/07/2023] Open
Abstract
The P2X7 receptor (P2X7R) is a membrane receptor for the extracellular adenosine triphosphate (ATP). It functions as a ligand-gated non-selective cation channel and can mediate formation of a large non-selective membrane pore. Activation of the P2X7R induces multiple downstream events, including oxidative stress, inflammatory responses and cell death. Although the P2X7R has been identified in the retinal pigment epithelium (RPE) and different layers of retina, its biological and pathological functions as well as its downstream signaling pathways in the RPE and retina are not yet fully understood. Better understanding of the function of P2X7R in the RPE and retina under normal and disease states might lead to novel therapeutic targets in retinal diseases, including age-related macular degeneration (AMD). This brief review will mainly focus on recent findings on in vitro and in vivo evidence for the role of the P2X7R in the RPE and AMD.
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28
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Hollborn M, Fischer S, Kuhrt H, Wiedemann P, Bringmann A, Kohen L. Osmotic regulation of NFAT5 expression in RPE cells: The involvement of purinergic receptor signaling. Mol Vis 2017; 23:116-130. [PMID: 28356704 PMCID: PMC5360457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 03/16/2017] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Systemic hypertension is a risk factor for age-related neovascular retinal diseases. The major condition that induces hypertension is the intake of dietary salt (NaCl) resulting in increased extracellular osmolarity. High extracellular NaCl was has been shown to induce angiogenic factor production in RPE cells, in part via the transcriptional activity of nuclear factor of activated T cell 5 (NFAT5). Here, we determined the signaling pathways that mediate the osmotic expression of the NFAT5 gene in RPE cells. METHODS Cultured human RPE cells were stimulated with high (+100 mM) NaCl. Alterations in gene and protein expression were determined with real-time reverse transcriptase (RT)-PCR and western blot analysis, respectively. RESULTS NaCl-induced NFAT5 gene expression was fully inhibited by calcium chelation and blockers of inositol triphosphate (IP3) receptors and phospholipases C and A2. Blockers of phospholipases C and A2 also prevented the NaCl-induced increase of the cellular NFAT5 protein level. Inhibitors of multiple intracellular signaling transduction pathways and kinases, including p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun NH2-terminal kinase (JNK), phosphatidylinositol-3 kinase (PI3K), protein kinases A and C, Src tyrosine kinases, and calpains, as well as cyclooxygenase inhibitors, decreased the NaCl-induced expression of the NFAT5 gene. In addition, autocrine purinergic signaling mediated by a release of ATP and a nucleoside transporter-mediated release of adenosine, activation of P2X7, P2Y1, P2Y2, and adenosine A1 receptors, but not adenosine A2A receptors, is required for the full expression of the NFAT5 gene under hyperosmotic conditions. NaCl-induced NFAT5 gene expression is in part dependent on the activity of nuclear factor κB (NF-κB). The NaCl-induced expression of NFAT5 protein was prevented by inhibitors of phospholipases C and A2 and an inhibitor of NF-κB, but it was not prevented by a P2Y1 inhibitor. CONCLUSIONS The data suggest that in addition to calcium signaling and activation of inflammatory enzymes, autocrine/paracrine purinergic signaling contributes to the stimulatory effect of hyperosmotic stress on the expression of the NFAT5 gene in RPE cells. It is suggested that high intake of dietary salt induces RPE cell responses, which may contribute to age-related retinal diseases.
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Affiliation(s)
- Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Sarah Fischer
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Paul Flechsig Institute of Brain Research, University of Leipzig Medical Faculty, Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany,Helios Klinikum Aue, Aue, Germany
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29
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Carver KA, Lin CM, Bowes Rickman C, Yang D. Lack of the P2X 7 receptor protects against AMD-like defects and microparticle accumulation in a chronic oxidative stress-induced mouse model of AMD. Biochem Biophys Res Commun 2016; 482:81-86. [PMID: 27810364 DOI: 10.1016/j.bbrc.2016.10.140] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 10/29/2016] [Indexed: 12/17/2022]
Abstract
The P2X7 receptor (P2X7R) is an ATP-gated ion channel that is a key player in oxidative stress under pathological conditions. The P2X7R is expressed in the retinal pigmented epithelium (RPE) and neural retina. Chronic oxidative stress contributes to the pathogenesis of age-related macular degeneration (AMD). Mice lacking Cu, Zn superoxide dismutase (Sod1) developed chronic oxidative stress as well as AMD-like features, but whether the P2X7R plays a causative role in oxidative stress-induced AMD is unknown. Thus, the main purpose of this study was to test if concurrent knockout (KO) of P2X7R could block AMD-like defects seen in Sod1 KO mice. Using multiple approaches, we demonstrate that Sod1 KO causes AMD-like defects, including positive staining for oxidative stress markers, 3-nitrotyrosine and carboxymethyl lysine, thinning of the RPE and retina, thickening of Bruch's membrane, presence of basal laminar and linear deposits, RPE barrier disruption and accumulation of microglia/macrophages. Moreover, we find that Sod1 KO mice accumulate more microparticles (MPs) within RPE/choroid tissues. Concurrent KO of the P2X7R protects against AMD-like defects and MP accumulation in Sod1 KO mice. Together, we show for the first time, that deficiency of P2X7R prevents in vivo oxidative stress-induced accumulation of MPs and AMD-like defects. This work could potentially lead to novel therapies for AMD and other oxidative stress-driven diseases.
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Affiliation(s)
- Kyle A Carver
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - C M Lin
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Catherine Bowes Rickman
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC 27710, USA; Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
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30
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Corso L, Cavallero A, Baroni D, Garbati P, Prestipino G, Bisti S, Nobile M, Picco C. Saffron reduces ATP-induced retinal cytotoxicity by targeting P2X7 receptors. Purinergic Signal 2016; 12:161-74. [PMID: 26739703 DOI: 10.1007/s11302-015-9490-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/15/2015] [Indexed: 11/25/2022] Open
Abstract
P2X7-type purinergic receptors are distributed throughout the nervous system where they contribute to physiological and pathological functions. In the retina, this receptor is found in both inner and outer cells including microglia modulating signaling and health of retinal cells. It is involved in retinal neurodegenerative disorders such as retinitis pigmentosa and age-related macular degeneration (AMD). Experimental studies demonstrated that saffron protects photoreceptors from light-induced damage preserving both retinal morphology and visual function and improves retinal flicker sensitivity in AMD patients. To evaluate a possible interaction between saffron and P2X7 receptors (P2X7Rs), different cellular models and experimental approaches were used. We found that saffron positively influences the viability of mouse primary retinal cells and photoreceptor-derived 661W cells exposed to ATP, and reduced the ATP-induced intracellular calcium increase in 661W cells. Similar results were obtained on HEK cells transfected with recombinant rat P2X7R but not on cells transfected with rat P2X2R. Finally, patch-clamp experiments showed that saffron inhibited cationic currents in HEK-P2X7R cells. These results point out a novel mechanism through which saffron may exert its protective role in neurodegeneration and support the idea that P2X7-mediated calcium signaling may be a crucial therapeutic target in the treatment of neurodegenerative diseases.
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Affiliation(s)
- Lucia Corso
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy.,Department of Biotechnology and Applied clinical Science, DISCAB, University of L'Aquila, L'Aquila, Italy
| | - Anna Cavallero
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy
| | - Debora Baroni
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy
| | - Patrizia Garbati
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy
| | - Gianfranco Prestipino
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy
| | - Silvia Bisti
- Department of Biotechnology and Applied clinical Science, DISCAB, University of L'Aquila, L'Aquila, Italy
| | - Mario Nobile
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy
| | - Cristiana Picco
- National Research Council, Institute of Biophysics, Via De Marini 6, 16149, Genoa, Italy.
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31
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Vainio I, Abu Khamidakh A, Paci M, Skottman H, Juuti-Uusitalo K, Hyttinen J, Nymark S. Computational Model of Ca2+ Wave Propagation in Human Retinal Pigment Epithelial ARPE-19 Cells. PLoS One 2015; 10:e0128434. [PMID: 26070134 PMCID: PMC4466493 DOI: 10.1371/journal.pone.0128434] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/27/2015] [Indexed: 12/21/2022] Open
Abstract
Objective Computational models of calcium (Ca2+) signaling have been constructed for several cell types. There are, however, no such models for retinal pigment epithelium (RPE). Our aim was to construct a Ca2+ signaling model for RPE based on our experimental data of mechanically induced Ca2+ wave in the in vitro model of RPE, the ARPE-19 monolayer. Methods We combined six essential Ca2+ signaling components into a model: stretch-sensitive Ca2+ channels (SSCCs), P2Y2 receptors, IP3 receptors, ryanodine receptors, Ca2+ pumps, and gap junctions. The cells in our epithelial model are connected to each other to enable transport of signaling molecules. Parameterization was done by tuning the above model components so that the simulated Ca2+ waves reproduced our control experimental data and data where gap junctions were blocked. Results Our model was able to explain Ca2+ signaling in ARPE-19 cells, and the basic mechanism was found to be as follows: 1) Cells near the stimulus site are likely to conduct Ca2+ through plasma membrane SSCCs and gap junctions conduct the Ca2+ and IP3 between cells further away. 2) Most likely the stimulated cell secretes ligand to the extracellular space where the ligand diffusion mediates the Ca2+ signal so that the ligand concentration decreases with distance. 3) The phosphorylation of the IP3 receptor defines the cell’s sensitivity to the extracellular ligand attenuating the Ca2+ signal in the distance. Conclusions The developed model was able to simulate an array of experimental data including drug effects. Furthermore, our simulations predict that suramin may interfere ligand binding on P2Y2 receptors or accelerate P2Y2 receptor phosphorylation, which may partially be the reason for Ca2+ wave attenuation by suramin. Being the first RPE Ca2+ signaling model created based on experimental data on ARPE-19 cell line, the model offers a platform for further modeling of native RPE functions.
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Affiliation(s)
- Iina Vainio
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- Institute of Biosciences and Medical Technology, Tampere University of Technology, Tampere, Finland
- * E-mail:
| | - Amna Abu Khamidakh
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- Institute of Biosciences and Medical Technology, Tampere University of Technology, Tampere, Finland
| | - Michelangelo Paci
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- Institute of Biosciences and Medical Technology, Tampere University of Technology, Tampere, Finland
| | - Heli Skottman
- Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland
| | - Kati Juuti-Uusitalo
- Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland
| | - Jari Hyttinen
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- Institute of Biosciences and Medical Technology, Tampere University of Technology, Tampere, Finland
| | - Soile Nymark
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- Institute of Biosciences and Medical Technology, Tampere University of Technology, Tampere, Finland
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32
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Reichenbach A, Bringmann A. Purinergic signaling in retinal degeneration and regeneration. Neuropharmacology 2015; 104:194-211. [PMID: 25998275 DOI: 10.1016/j.neuropharm.2015.05.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/07/2015] [Accepted: 05/07/2015] [Indexed: 02/01/2023]
Abstract
Purinergic signaling is centrally involved in mediating the degeneration of the injured and diseased retina, the induction of retinal gliosis, and the protection of the retinal tissue from degeneration. Dysregulated calcium signaling triggered by overactivation of P2X7 receptors is a crucial step in the induction of neuronal and microvascular cell death under pathogenic conditions like ischemia-hypoxia, elevated intraocular pressure, and diabetes, respectively. Overactivation of P2X7 plays also a pathogenic role in inherited and age-related photoreceptor cell death and in the age-related dysfunction and degeneration of the retinal pigment epithelium. Gliosis of micro- and macroglial cells, which is induced and/or modulated by purinergic signaling and associated with an impaired homeostatic support to neurons, and the ATP-mediated propagation of retinal gliosis from a focal injury into the surrounding noninjured tissue are involved in inducing secondary cell death in the retina. On the other hand, alterations in the glial metabolism of extracellular nucleotides, resulting in a decreased level of ATP and an increased level of adenosine, may be neuroprotective in the diseased retina. Purinergic signals stimulate the proliferation of retinal glial cells which contributes to glial scarring which has protective effects on retinal degeneration and adverse effects on retinal regeneration. Pharmacological modulation of purinergic receptors, e.g., inhibition of P2X and activation of adenosine receptors, may have clinical importance for the prevention of photoreceptor, neuronal, and microvascular cell death in diabetic retinopathy, retinitis pigmentosa, age-related macular degeneration, and glaucoma, respectively, for the clearance of retinal edema, and the inhibition of dysregulated cell proliferation in proliferative retinopathies. This article is part of a Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany.
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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33
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Sakamoto K, Endo K, Suzuki T, Fujimura K, Kurauchi Y, Mori A, Nakahara T, Ishii K. P2X7 receptor antagonists protect against N-methyl-D-aspartic acid-induced neuronal injury in the rat retina. Eur J Pharmacol 2015; 756:52-8. [PMID: 25796199 DOI: 10.1016/j.ejphar.2015.03.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 03/03/2015] [Accepted: 03/11/2015] [Indexed: 01/02/2023]
Abstract
Activation of N-methyl-d-aspartic acid (NMDA) receptors followed by a large Ca(2+) influx is thought to be a mechanism of glaucoma-induced neuronal cell death. It is possible that damage-associated molecular patterns leak from injured cells, such as adenosine triphosphate, causing retinal ganglion cell death in glaucoma. In the present study, we histologically investigated whether antagonists of the P2X7 receptor protected against NMDA-induced retinal injury in the rat in vivo. Under ketamine/xylazine anesthesia, male Sprague-Dawley rats were subjected to intravitreal injection of NMDA. We used A438079 (3-(5-(2,3-dichlorophenyl)-1H-tetrazol-1-yl)methyl pyridine) and brilliant blue G as P2X7 receptor antagonists. Upon morphometric evaluation 7 days after an intravitreal injection (200 nmol/eye), NMDA-induced cell loss was apparent in the ganglion cell layer. Intravitreal A438079 (50 pmol/eye) simultaneously injected with NMDA and intraperitoneal brilliant blue G (50 mg/kg) administered just before the NMDA injection as well as 24 and 48h after significantly reduced cell loss. In addition, A438079 decreased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells 12h after NMDA injection. P2X7 receptors were immunolocalized in the ganglion cell layer and the inner and outer plexiform layers, whereas the immunopositive P2X7 receptor signal was not detected on the Iba1-positive microglial cells that infiltrated the retina 12h after NMDA injection. The present study shows that stimulation of the P2X7 receptor is involved in NMDA-induced histological damage in the rat retina in vivo. P2X7 receptor antagonists may be effective in preventing retinal diseases caused by glutamate excitotoxicity, such as glaucoma and retinal artery occlusion.
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Affiliation(s)
- Kenji Sakamoto
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan.
| | - Kanako Endo
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
| | - Taishi Suzuki
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
| | - Kyosuke Fujimura
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
| | - Yuki Kurauchi
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
| | - Asami Mori
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
| | - Tsutomu Nakahara
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
| | - Kunio Ishii
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Tokyo 108-8641, Japan
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Robinson LE, Shridar M, Smith P, Murrell-Lagnado RD. Plasma membrane cholesterol as a regulator of human and rodent P2X7 receptor activation and sensitization. J Biol Chem 2014; 289:31983-31994. [PMID: 25281740 PMCID: PMC4231676 DOI: 10.1074/jbc.m114.574699] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
P2X7 receptors are nonselective cation channels gated by high extracellular ATP, but with sustained activation, receptor sensitization occurs, whereby the intrinsic pore dilates, making the cell permeable to large organic cations, which eventually leads to cell death. P2X7 receptors associate with cholesterol-rich lipid rafts, but it is unclear how this affects the properties of the receptor channel. Here we show that pore-forming properties of human and rodent P2X7 receptors are sensitive to perturbations of cholesterol levels. Acute depletion of cholesterol with 5 mm methyl-β-cyclodextrin (MCD) caused a substantial increase in the rate of agonist-evoked pore formation, as measured by the uptake of ethidium dye, whereas cholesterol loading inhibited this process. Patch clamp analysis of P2X7 receptor currents carried by Na+ and N-methyl-d-glucamine (NMDG+) showed enhanced activation and current facilitation following cholesterol depletion. This contrasts with the inhibitory effect of methyl-β-cyclodextrin reported for other P2X subtypes. Mutational analysis suggests the involvement of an N-terminal region and a proximal C-terminal region that comprises multiple cholesterol recognition amino acid consensus (CRAC) motifs, in the cholesterol sensitivity of channel gating. These results reveal cholesterol as a negative regulator of P2X7 receptor pore formation, protecting cells from P2X7-mediated cell death.
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Affiliation(s)
- Lucy E Robinson
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Mitesh Shridar
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Philip Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Ruth D Murrell-Lagnado
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom.
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35
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Sugiyama T. Role of P2X7 receptors in neuronal death in the retina. Neural Regen Res 2014; 9:579-81. [PMID: 25206858 PMCID: PMC4146243 DOI: 10.4103/1673-5374.130090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2014] [Indexed: 01/19/2023] Open
Affiliation(s)
- Tetsuya Sugiyama
- Nakano Eye Clinic of Kyoto Medical Co-operative, Kyoto 604-8404, Japan ; Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
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36
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Sugiyama T, Lee SY, Horie T, Oku H, Takai S, Tanioka H, Kuriki Y, Kojima S, Ikeda T. P2X₇ receptor activation may be involved in neuronal loss in the retinal ganglion cell layer after acute elevation of intraocular pressure in rats. Mol Vis 2013; 19:2080-91. [PMID: 24146541 PMCID: PMC3786454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 09/26/2013] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate whether the P2X₇ receptor is involved in retinal ganglion cell (RGC) death after the intraocular pressure (IOP) is elevated in rats. METHODS After the IOP was elevated to 90 mmHg for 1 h, the rats were subsequently administered oxidized adenosine triphosphate (OxATP) and brilliant blue G (BBG) as P2X₇ antagonists. The rats were euthanized 7 days after IOP elevation for histologic evaluation and at 1, 3, and 7 days after IOP elevation to immunostain for the P2X₇ receptor and neuron-specific class III β-tubulin in the retina. Changes in P2X₇ receptor expression were measured in total retina extracts using western blot analysis. Quantitative real-time PCR was also performed using the entire retina to determine whether the P2X₇ receptor is involved in upregulating tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 at 1, 2, and 3 days after the IOP was elevated. RESULTS RGC density and the inner plexiform layer thickness significantly decreased 7 days after IOP elevation, but were dose-dependently preserved when treated with OxATP or BBG. P2X₇ immunoreactivity in the RGCs increased after IOP elevation, with the peak occurring from day 1 through day 3. Protein levels of P2X₇ receptor were significantly increased 1, 2, and 3 days after IOP elevation. The messenger ribonucleic acid expression of the P2X₇ receptor, TNF-α, IL-1β, and IL-6 was significantly upregulated in the retina after IOP elevation, and was suppressed by treatment with OxATP. CONCLUSIONS These results suggest the expression of the P2X₇ receptor is upregulated in the retina after IOP elevation, leading to RGC death. Upregulation of TNF-α, IL-1β, and IL-6 might be involved in this mechanism of RGC death. Furthermore, P2X₇ antagonists may prevent RGC death after IOP elevation.
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Affiliation(s)
- Tetsuya Sugiyama
- Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan
| | | | - Taeko Horie
- Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Hidehiro Oku
- Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Shinji Takai
- Department of Pharmacology, Osaka Medical College, Osaka, Japan
| | - Hidetoshi Tanioka
- Nara Research and Development Center, Santen Pharmaceutical Co. Ltd., Takayama-cho, Ikoma-shi, Nara, Japan
| | - Yumi Kuriki
- Nara Research and Development Center, Santen Pharmaceutical Co. Ltd., Takayama-cho, Ikoma-shi, Nara, Japan
| | - Shota Kojima
- Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Tsunehiko Ikeda
- Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan
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Guha S, Baltazar GC, Coffey EE, Tu LA, Lim JC, Beckel JM, Patel S, Eysteinsson T, Lu W, O'Brien-Jenkins A, Laties AM, Mitchell CH. Lysosomal alkalinization, lipid oxidation, and reduced phagosome clearance triggered by activation of the P2X7 receptor. FASEB J 2013; 27:4500-9. [PMID: 23964074 DOI: 10.1096/fj.13-236166] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lysosomal enzymes function optimally at low pH; as accumulation of waste material contributes to cell aging and disease, dysregulation of lysosomal pH may represent an early step in several pathologies. Here, we demonstrate that stimulation of the P2X7 receptor (P2X7R) for ATP alkalinizes lysosomes in cultured human retinal pigmented epithelial (RPE) cells and impairs lysosomal function. P2X7R stimulation did not kill RPE cells but alkalinized lysosomes by 0.3 U. Receptor stimulation also elevated cytoplasmic Ca(2+); Ca(2+) influx was necessary but not sufficient for lysosomal alkalinization. P2X7R stimulation decreased access to the active site of cathepsin D. Interestingly, lysosomal alkalinization was accompanied by a rise in lipid oxidation that was prevented by P2X7R antagonism. Likewise, the autofluorescence of phagocytosed photoreceptor outer segments increased by lysosomal alkalinization was restored 73% by a P2X7R antagonist. Together, this suggests that endogenous autostimulation of the P2X7R may oxidize lipids and impede clearance. The P2X7R was expressed on apical and basolateral membranes of mouse RPE; mRNA expression of P2X7R and extracellular ATP marker NTPDase1 was raised in RPE tissue from the ABCA4(-/-) mouse model of Stargardt's retinal degeneration. In summary, P2X7R stimulation raises lysosomal pH and impedes lysosomal function, suggesting a possible role for overstimulation in diseases of accumulation.
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Affiliation(s)
- Sonia Guha
- 1Department of Anatomy and Cell Biology, University of Pennsylvania, 440 Levy Bldg., 240 S. 40th St., Philadelphia, PA 19104, USA.
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Guzman-Aranguez A, Santano C, Martin-Gil A, Fonseca B, Pintor J. Nucleotides in the eye: focus on functional aspects and therapeutic perspectives. J Pharmacol Exp Ther 2013; 345:331-41. [PMID: 23504005 DOI: 10.1124/jpet.112.202473] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The presence and activity of nucleotides and dinucleotides in the physiology of most, if not all, organisms, from bacteria to humans, have been recognized by the scientific community, and the eye is no exception. Nucleotides in the dynamic fluids interact with many ocular structures, such as the tears and aqueous humor. Moreover, high concentrations of nucleotides in these secretions may reflect disease states such as dry eye and glaucoma. Apart from the nucleotide concentration in these fluids, P2 purinergic receptors have been described on the ocular surface (cornea and conjunctiva), anterior pole (ciliary body, trabecular meshwork), and posterior pole (retina). P2X and P2Y purinergic receptors are essential in maintaining the homeostasis of ocular processes, such as tear secretion, aqueous humor production, or retinal modulation. When they are functioning properly, they allow the eye to do its job (to see), but in some cases, a lack or an excess of nucleotides or a malfunction in the corresponding purinergic receptors leads to disease. This Perspective is focused on the nucleotides and dinucleotides and the P2 purinergic receptors in the eye and how they contribute to normal and disease states. We also emphasize the action of nucleotides and their receptors and antagonists as potential therapeutic agents.
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Affiliation(s)
- Ana Guzman-Aranguez
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Universidad Complutense Madrid, C/Arcos de Jalón 118, 28037 Madrid, Spain
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Notomi S, Hisatomi T, Murakami Y, Terasaki H, Sonoda S, Asato R, Takeda A, Ikeda Y, Enaida H, Sakamoto T, Ishibashi T. Dynamic increase in extracellular ATP accelerates photoreceptor cell apoptosis via ligation of P2RX7 in subretinal hemorrhage. PLoS One 2013; 8:e53338. [PMID: 23308196 PMCID: PMC3540091 DOI: 10.1371/journal.pone.0053338] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Accepted: 11/27/2012] [Indexed: 02/05/2023] Open
Abstract
Photoreceptor degeneration is the most critical cause of visual impairment in age-related macular degeneration (AMD). In neovascular form of AMD, severe photoreceptor loss develops with subretinal hemorrhage due to choroidal neovascularization (CNV), growth of abnormal blood vessels from choroidal circulation. However, the detailed mechanisms of this process remain elusive. Here we demonstrate that neovascular AMD with subretinal hemorrhage accompanies a significant increase in extracellular ATP, and that extracellular ATP initiates neurodegenerative processes through specific ligation of Purinergic receptor P2X, ligand-gated ion channel, 7 (P2RX7; P2X7 receptor). Increased extracellular ATP levels were found in the vitreous samples of AMD patients with subretinal hemorrhage compared to control vitreous samples. Extravascular blood induced a massive release of ATP and photoreceptor cell apoptosis in co-culture with primary retinal cells. Photoreceptor cell apoptosis accompanied mitochondrial apoptotic pathways, namely activation of caspase-9 and translocation of apoptosis-inducing factor (AIF) from mitochondria to nuclei, as well as TUNEL-detectable DNA fragmentation. These hallmarks of photoreceptor cell apoptosis were prevented by brilliant blue G (BBG), a selective P2RX7 antagonist, which is an approved adjuvant in ocular surgery. Finally, in a mouse model of subretinal hemorrhage, photoreceptor cells degenerated through BBG-inhibitable apoptosis, suggesting that ligation of P2RX7 by extracellular ATP may accelerate photoreceptor cell apoptosis in AMD with subretinal hemorrhage. Our results indicate a novel mechanism that could involve neuronal cell death not only in AMD but also in hemorrhagic disorders in the CNS and encourage the potential application of BBG as a neuroprotective therapy.
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Affiliation(s)
- Shoji Notomi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshio Hisatomi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Clinical Research Institute, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroto Terasaki
- Department of Ophthalmology, Graduate School of Medical Sciences, Kagoshima University, Kagoshima, Japan
| | - Shozo Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kagoshima University, Kagoshima, Japan
| | - Ryo Asato
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Clinical Research Institute, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan
| | - Atsunobu Takeda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuhiro Ikeda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroshi Enaida
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Taiji Sakamoto
- Department of Ophthalmology, Graduate School of Medical Sciences, Kagoshima University, Kagoshima, Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Kakurai K, Sugiyama T, Kurimoto T, Oku H, Ikeda T. Involvement of P2X(7) receptors in retinal ganglion cell death after optic nerve crush injury in rats. Neurosci Lett 2012; 534:237-41. [PMID: 23262079 DOI: 10.1016/j.neulet.2012.11.060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 10/27/2012] [Accepted: 11/22/2012] [Indexed: 11/25/2022]
Abstract
We investigated whether P2X(7) antagonists rescue retinal ganglion cells (RGCs) in culture and after optic nerve crush (ONC) injury. Rats were sacrificed 7 days after retrograde labeling of RGCs with 4',6-diamidino-2-phenylindole (DAPI), and the retinas were enzymatically dissociated in vitro and incubated with P2X(7) antagonists or agonists for 3 days. Adenosine triphosphate (ATP) and benzoylbenzoyl ATP were used as P2X(7) agonists, and oxidized ATP and brilliant blue G were used as P2X(7) antagonists. DAPI-positive and calcein-positive RGCs were counted to determine the number of living cells. We observed that RGCs were preserved when treated with P2X(7) antagonists, as compared with the controls. In contrast, P2X(7) agonists significantly decreased the number of viable RGCs. In vivo, P2X(7) antagonists at various doses were injected into the vitreous body immediately after ONC injuries in rats. Surviving RGCs were stained with anti-neuron-specific β-tubulin antibody in flat-mounted retinas. RGCs were observed to decrease to 61% of baseline 7 days after ONC injury, whereas RGCs were significantly preserved when P2X(7) antagonists were applied. When P2X(7) receptor expression was examined immunohistochemically in rat retinas after ONC, the retinal expression of the P2X(7) receptors was observed to be upregulated after ONC and peaked on day 3. Meanwhile, P2X(7) antagonists suppressed this upregulation. Collectively, these results suggest that P2X(7) antagonists prevent loss of RGCs after ONC, and that this protective effect is possibly mediated through suppressing the upregulation of retinal P2X(7) expression.
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Affiliation(s)
- Keigo Kakurai
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan
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Li X, Arslan F, Ren Y, Adav SS, Poh KK, Sorokin V, Lee CN, de Kleijn D, Lim SK, Sze SK. Metabolic adaptation to a disruption in oxygen supply during myocardial ischemia and reperfusion is underpinned by temporal and quantitative changes in the cardiac proteome. J Proteome Res 2012; 11:2331-46. [PMID: 22352837 DOI: 10.1021/pr201025m] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Despite decades of intensive research, there is still no effective treatment for ischemia/reperfusion (I/R) injury, an important corollary in the treatment of ischemic disease. I/R injury is initiated when the altered biochemistry of cells after ischemia is no longer compatible with oxygenated microenvironment (or reperfusion). To better understand the molecular basis of this alteration and subsequent incompatibility, we assessed the temporal and quantitative alterations in the cardiac proteome of a mouse cardiac I/R model by an iTRAQ approach at 30 min of ischemia, and at 60 or 120 min reperfusion after the ischemia using sham-operated mouse heart as the baseline control. Of the 509 quantified proteins identified, 121 proteins exhibited significant changes (p-value<0.05) over time and were mostly clustered in eight functional groups: Fatty acid oxidation, Glycolysis, TCA cycle, ETC (electron transport chain), Redox Homeostasis, Glutathione S-transferase, Apoptosis related, and Heat Shock proteins. The first four groups are intimately involved in ATP production and the last four groups are known to be important in cellular antioxidant activity. During ischemia and reperfusion, the short supply of oxygen precipitates a pivotal metabolic switch from aerobic metabolism involving fatty acid oxidation, TCA, and phosphorylation to anaerobic metabolism for ATP production and this, in turn, increases reactive oxygen species (ROS) formation. Therefore the implication of these 8 functional groups suggested that ischemia-reperfusion injury is underpinned in part by proteomic alterations. Reversion of these alterations to preischemia levels took at least 60 min, suggesting a refractory period in which the ischemic cells cannot adjust to the presence of oxygen. Therefore, therapeutics that could compensate for these proteomic alterations during this interim refractory period could alleviate ischemia-reperfusion injury to enhance cellular recovery from an ischemic to a normoxic microenvironment. Among the perturbed proteins, Park7 and Ppia were selected for further investigation of their functions under hypoxia. The results show that Park7 plays a key role in regulating antioxidative stress and cell survival, and Ppia may function in coping with the unfolded protein stress in the I/R condition.
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Affiliation(s)
- Xin Li
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
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42
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Field MG, Yang D, Bian ZM, Petty HR, Elner VM. Retinal flavoprotein fluorescence correlates with mitochondrial stress, apoptosis, and chemokine expression. Exp Eye Res 2011; 93:548-55. [PMID: 21767533 PMCID: PMC3206137 DOI: 10.1016/j.exer.2011.06.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/16/2011] [Accepted: 06/28/2011] [Indexed: 12/31/2022]
Abstract
Oxidative stress and mitochondrial dysfunction occur before apoptosis in many retinal diseases. Under these conditions, a larger fraction of flavoproteins become oxidized and, when excited by blue-light, emit green flavoprotein fluorescence (FPF). In this study, we evaluated the utility of FPF as an early indicator of mitochondrial stress, pre-apoptotic cellular instability, and apoptosis of human retinal pigment epithelial (HRPE) cells subjected to hydrogen peroxide (H(2)O(2)) or monocytes (unstimulated or interferon-γ-stimulated) in vitro and of freshly-isolated pieces of human and rat neural retina subjected to H(2)O(2)ex vivo. Increased FPF of HRPE cells exposed to H(2)O(2) correlated with reduced mitochondrial membrane potential (ΔΨm) and increased apoptosis in a time- and dose-dependent manner. HRPE cells co-cultured with monocytes had increased FPF that correlated in a time-dependent manner with reduced ΔΨm, increased apoptosis, and early expression of pro-inflammatory chemokines, interleukin-8 (IL8) and monocyte chemotactic factor-1 (MCP1), which are known to be induced by oxidative stress. Increased FPF, reduced ΔΨm, and upregulation of IL8 and MCP1 occurred as early as 1-2 h after exposure to stressors, while apoptosis did not occur in HRPE cells until later time points. The antioxidant, N-acetyl-cysteine (NAC), inhibited increased FPF and apoptosis of HRPE cells subjected to H(2)O(2). Increased FPF of human and rat neural retina also correlated with increased apoptosis. This study suggests that FPF is a useful measure of mitochondrial function in retinal cells and tissues and can detect early mitochondrial dysfunction that may precede apoptosis.
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Affiliation(s)
- Matthew G. Field
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Zong-Mei Bian
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Howard R. Petty
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan
| | - Victor M. Elner
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
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Yang D, Elner SG, Chen X, Field MG, Petty HR, Elner VM. MCP-1-activated monocytes induce apoptosis in human retinal pigment epithelium. Invest Ophthalmol Vis Sci 2011; 52:6026-34. [PMID: 21447688 DOI: 10.1167/iovs.10-7023] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE The inflammatory response in age-related macular degeneration (AMD) is characterized by mononuclear leukocyte infiltration of the outer blood-retina barrier formed by the retinal pigment epithelium (RPE). A key mechanistic element in AMD progression is RPE dysfunction and apoptotic cell loss. The purpose of this study was to evaluate whether monocyte chemoattractant protein (MCP)-1-activated monocytes induce human RPE apoptosis and whether Ca(2+) and reactive oxygen species (ROS) are involved in this process. METHODS A cell-based fluorometric assay was used to measure intracellular Ca(2+) concentrations ([Ca(2+)](i)) in RPE cells loaded with fluorescent Ca(2+) indicator. Intracellular RPE ROS levels were measured by using the 5- and 6-chloromethyl-2',7'-dichlorodihydrofluorescence diacetate acetyl ester (CM-H(2)DCFDA) assay. RPE apoptosis was evaluated by activated caspase-3, Hoechst staining, and apoptosis ELISA. RESULTS MCP-1-activated human monocytes increased [Ca(2+)](i), ROS levels, and apoptosis in RPE cells, all of which were inhibited by 8-bromo-cyclic adenosine diphosphoribosyl ribose (8-Br-cADPR), an antagonist of cADPR. Although the ROS scavengers pyrrolidinedithiocarbamate (PDTC) and N-acetylcysteine (NAC) significantly inhibited ROS production and apoptosis induced by activated monocytes, they did not affect induced Ca(2+) levels. The induced Ca(2+) levels and apoptosis in RPE cells were inhibited by an antibody against cluster of differentiation antigen 14 (CD14), an adhesion molecule expressed by these cells. CONCLUSIONS These results indicate that CD14, Ca(2+), and ROS are involved in activated monocyte-induced RPE apoptosis and that cADPR contributes to these changes. Understanding the complex interactions among CD14, cADPR, Ca(2+), and ROS may provide new insights and treatments of retinal diseases, including AMD.
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Affiliation(s)
- Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan 48105-0714, USA
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Wang WJ, Ma Z, Liu YW, He YQ, Wang YZ, Yang CX, Du Y, Zhou MQ, Gao F. A monoclonal antibody (Mc178-Ab) targeted to the ecto-ATP synthase β-subunit-induced cell apoptosis via a mechanism involving the MAPKase and Akt pathways. Clin Exp Med 2011; 12:3-12. [PMID: 21505868 DOI: 10.1007/s10238-011-0133-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 03/17/2011] [Indexed: 12/19/2022]
Abstract
Ecto-ATP synthase has been considered to be an effective target for cancer recently. As inhibitors of ecto-ATP synthase were found to be cytotoxic for tumor cells, a monoclonal antibody (Mc178-Ab) against ecto-ATP synthase was generated in our previous study that exhibited both anti-angiogenic and anti-tumorigenic effects. However, the mechanism of action of Mc178-Ab and its downstream pathways for anti-tumor effects remain unclear. In this research, we intended to investigate the mechanism of the anti-tumor action of Mc178-Ab. The expressions of cell surface ATP synthase on A549 and CHO cells were confirmed by flow cytometry and confocal microscope. Proliferation and apoptosis were examined after the treatment with Mc178-Ab. In order to examine the activity of ecto-ATP synthase changed by Mc178-Ab, extracellular ATP generation and intracellular pH levels were assessed. The phosphorylation of the signaling molecules, MAPKase and Akt, was analyzed by western blot. Cell proliferation was blocked, and apoptosis was induced in A549 cells treated with Mc178-Ab, as determined by MTT assay and flow cytometry analysis of Annexin-V/PI staining separately. The intracellular pH level and extracellular ATP generation were also decreased after Mc178-Ab treatment. Finally, western blot data revealed that the phosphorylation of JNK and p38 was increased, while the phosphorylation of ERK and Akt was decreased in A549 cells treated with Mc178-Ab. Compared with A549 cells, Mc178-Ab had less effect on CHO cells. The decreased intracellular pH levels and the altered concentration of extracellular ATP may contribute to the mechanisms of the effect of Mc178-Ab on A549 and CHO cells. The results also suggested that the anti-tumor effect of Mc178-Ab was associated with MAPKase and Akt pathways.
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Affiliation(s)
- Wen-Juan Wang
- Department of Molecular Biology Laboratory, Shanghai Sixth People's Hospital of Shanghai, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
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