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Liu Y, Lu CY, Zheng Y, Zhang YM, Qian LL, Li KL, Tse G, Wang RX, Liu T. Role of angiotensin receptor-neprilysin inhibitor in diabetic complications. World J Diabetes 2024; 15:867-875. [PMID: 38766431 PMCID: PMC11099356 DOI: 10.4239/wjd.v15.i5.867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/31/2023] [Accepted: 03/25/2024] [Indexed: 05/10/2024] Open
Abstract
Diabetes mellitus is a prevalent disorder with multi-system manifestations, causing a significant burden in terms of disability and deaths globally. Angio-tensin receptor-neprilysin inhibitor (ARNI) belongs to a class of medications for treating heart failure, with the benefits of reducing hospitalization rates and mortality. This review mainly focuses on the clinical and basic investigations related to ARNI and diabetic complications, discussing possible physiological and molecular mechanisms, with insights for future applications.
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Affiliation(s)
- Ying Liu
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Cun-Yu Lu
- Department of Cardiology, Xuzhou No. 1 Peoples Hospital, Xuzhou 221005, Jiangsu Province, China
| | - Yi Zheng
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Yu-Min Zhang
- Department of Cardiology, Wuxi 9th People’s Hospital Affiliated to Soochow University, Wuxi 214062, Jiangsu Province, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, Jiangsu Province, China
| | - Ku-Lin Li
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, Jiangsu Province, China
| | - Gary Tse
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
- School of Nursing and Health Studies, Metropolitan University, Hong Kong 999077, China
- Kent and Medway Medical School, Kent CT2 7NT, Canterbury, United Kingdom
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, Jiangsu Province, China
| | - Tong Liu
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
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Ahmad S, Wright KN, VonCannon JL, Ferrario CM, Ola MS, Choudhary M, Malek G, Gustafson JR, Sappington RM. Internalization of Angiotensin-(1-12) in Adult Retinal Pigment Epithelial-19 Cells. J Ocul Pharmacol Ther 2023; 39:290-299. [PMID: 36944130 PMCID: PMC10178934 DOI: 10.1089/jop.2022.0139] [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: 09/22/2022] [Accepted: 02/12/2023] [Indexed: 03/23/2023] Open
Abstract
Purpose: Angiotensin-(1-12) [Ang-(1-12)] serves as a primary substrate to generate angiotensin II (Ang II) by angiotensin-converting enzyme and/or chymase suggests it may be an unrecognized source of Ang II-mediated microvascular complication in hypertension-mediated retinopathy. We investigated Ang-(1-12) expression and internalization in adult retinal pigment epithelial-19 (ARPE-19) cultured cells. We performed the internalization of Ang-(1-12) in ARPE-19 cells in the presence of a highly specific monoclonal antibody (mAb) developed against the C-terminal end of the Ang-(1-12) sequence. Methods: All experiments were performed in confluent ARPE-19 cells (passage 28-35). We employed high-performance liquid chromatography to purify radiolabeled, 125I-Ang-(1-12) and immuno-neutralization with Ang-(1-12) mAb to demonstrate Ang-(1-12)'s internalization in ARPE-19 cells. Internalization was also demonstrated by immunofluorescence (IF) method. Results: These procedures revealed internalization of an intact 125I-Ang-(1-12) in ARPE-19 cells. A significant reduction (∼53%, P < 0.0001) in 125I-Ang-(1-12) internalization was detected in APRE-19 cells in the presence of the mAb. IF staining experiments further confirms internalization of Ang-(1-12) into the cells from the extracellular culture medium. No endogenous expression was detected in the ARPE-19 cells. An increased intensity of IF staining was detected in cells exposed to 1.0 μM Ang-(1-12) compared with 0.1 μM. Furthermore, we found hydrolysis of Ang-(1-12) into Ang II by ARPE-19 cells' plasma membranes. Conclusions: Intact Ang-(1-12) peptide is internalized from the extracellular spaces in ARPE-19 cells and metabolized into Ang II. The finding that a selective mAb blocks cellular internalization of Ang-(1-12) suggests alternate therapeutic approaches to prevent/reduce the RPE cells Ang II burden.
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Affiliation(s)
- Sarfaraz Ahmad
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Kendra N. Wright
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Jessica L. VonCannon
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Carlos M. Ferrario
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Mohammad S. Ola
- Department of Biochemistry, King Saud University, Riyadh, Saudi Arabia
| | - Mayur Choudhary
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Goldis Malek
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Jenna R. Gustafson
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Rebecca M. Sappington
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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Fan M, Miao Y, Yan Y, Zhu K, Zhao X, Pan M, Ma B, Wei Q. C-Type Natriuretic Peptide Regulates the Expression and Secretion of Antibacterial Peptide S100A7 in Goat Mammary Gland Through PKG/JNK/c-Jun Signaling Pathway. Front Vet Sci 2022; 9:822165. [PMID: 35498722 PMCID: PMC9039262 DOI: 10.3389/fvets.2022.822165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
During infection, the infected tissue secretes a variety of endogenous peptides to resist further invasion of pathogens. Among these endogenous peptides, the natriuretic peptides and the antimicrobial peptides attracted the most attention. C-type natriuretic peptide (CNP) and its receptor natriuretic peptide receptor B (NPR-B) were members of the natriuretic peptide system. The antimicrobial peptide S100A7 plays an important role to resist infection of bacteria in mastitis. It is reported that the expression of S100A7 is regulated by an activator protein-1 (AP-1)-responsive promoter. As a subunit of AP-1, c-Jun is a downstream target of CNP/NPR-B signaling pathway. Therefore, it is a hypothesis that the CNP/NPR-B signaling pathway induces the expression and secretion of S100A7 in mammary glands to take part in local mammary gland innate immunity. To verify this hypothesis, goat mammary gland and isolated mammary epithelial cells (MECs) were used to explore the expression of CNP/NPR-B and their physiological roles in goat mammary gland. The results showed that goat mammary gland expressed NPR-B, but not CNP. The expression and secretion of S100A7 in goat MECs were obviously induced by CNP/NPR-B signaling pathway. After treatment with CNP, the cyclic guanosine monophosphate (cGMP) level in goat MECs was significantly upregulated. Along with the upregulation of cGMP level, the phosphorylation levels of c-Jun N-terminal kinase (JNK) and its target c-Jun were also increased gradually. KT5823 is a specific inhibitor for protein kinase G (PKG). KT5823 remarkably inhibited the phosphorylation of JNK and c-Jun induced by CNP. Correspondingly, KT5823 evidently inhibited the expression and secretion of S100A7 induced by CNP. On the other hand, the expression of NPR-B and S100A7 was upregulated in the mastitis goat mammary gland. But, there was no significant difference in expression of CNP between healthy and mastitis goat mammary gland tissues. The goat mastitis model was established in vitro using goat MECs treated by lipopolysaccharide (LPS). LPS treatment also could increase the expression of NPR-B and S100A7. In conclusion, goat mammary gland expressed NPR-B, indicating mammary gland was the target organ for natriuretic peptide system. Moreover, CNP, through NPR-B/JNK/c-Jun signaling pathway to regulate the expression and secretion of S100A7 in MECs, played an important role in mammary gland innate immunity.
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Affiliation(s)
- Mingzhen Fan
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Yuyang Miao
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Yutong Yan
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Kunyuan Zhu
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Xiaoe Zhao
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Menghao Pan
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Baohua Ma
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- *Correspondence: Baohua Ma
| | - Qiang Wei
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Qiang Wei
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4
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Tonade D, Kern TS. Photoreceptor cells and RPE contribute to the development of diabetic retinopathy. Prog Retin Eye Res 2021; 83:100919. [PMID: 33188897 PMCID: PMC8113320 DOI: 10.1016/j.preteyeres.2020.100919] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 10/27/2020] [Accepted: 10/31/2020] [Indexed: 12/26/2022]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness. It has long been regarded as vascular disease, but work in the past years has shown abnormalities also in the neural retina. Unfortunately, research on the vascular and neural abnormalities have remained largely separate, instead of being integrated into a comprehensive view of DR that includes both the neural and vascular components. Recent evidence suggests that the most predominant neural cell in the retina (photoreceptors) and the adjacent retinal pigment epithelium (RPE) play an important role in the development of vascular lesions characteristic of DR. This review summarizes evidence that the outer retina is altered in diabetes, and that photoreceptors and RPE contribute to retinal vascular alterations in the early stages of the retinopathy. The possible molecular mechanisms by which cells of the outer retina might contribute to retinal vascular damage in diabetes also are discussed. Diabetes-induced alterations in the outer retina represent a novel therapeutic target to inhibit DR.
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Affiliation(s)
- Deoye Tonade
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Timothy S Kern
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA; Veterans Administration Medical Center Research Service, Cleveland, OH, USA; Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA; Veterans Administration Medical Center Research Service, Long Beach, CA, USA.
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Li Q, Qian X, Li HY, Lai KL, Gao Q, Lee WYT. Safety assessment of polymeric micelles as an ophthalmic drug delivery system for intravitreal administration of dasatinib. Int J Pharm 2021; 596:120226. [PMID: 33484922 DOI: 10.1016/j.ijpharm.2021.120226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/15/2020] [Accepted: 01/01/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND AIMS Ocular safety/biocompatibility is an essential element of ophthalmic drug delivery. We previously applied poly(ethylene glycol)-block-poly(ɛ-caprolactone) (PEG-b-PCL) micelles to deliver dasatinib for the management of proliferative vitreoretinopathy (PVR) in vitro. Herein, we seek to ascertain the ocular safety/compatibility of blank and dasatinib loaded PEG-b-PCL micelles, which will set the stage for the future in vivo efficacy evaluations and/or clinical translation for PVR or other eye diseases. METHODS To access the safety of blank and dasatinib loaded micelles, in vitro cell based assays (LDH cell membrane damage test, SRB cytotoxicity, TEER and permeability of RPE tight junctions), in vivo slit lamp biomicroscopy and optical coherence tomography, Ex vivo histology (H&E staining, GFAP immunofluorescence staining and TUNEL assay) were undertaken. RESULTS Both blank and dasatinib loaded micelles showed remarkable safety profiles at cellular levels. They also caused negligible ocular toxicity/abnormalities up to 28 days post-intravitreal injection in mice. The micelles did not insult the cornea, as demonstrated by slit-lamp biomicroscopy. Ex vivo histology and in vivo optical coherence tomography revealed a normal retinal structure with minimal apoptosis and stresses. CONCLUSION Taken together, both blank and dasatinib loaded micelles appear to be safe and their applications in drug delivery for eye diseases should be explored.
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Affiliation(s)
- Qingqing Li
- Faculty of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, China; School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - Xiaobing Qian
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Ho Yin Li
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong; Aptorum Therapeutics Limited, 17/F Guangdong Investment Tower, 148 Connaught Road Central, Hong Kong
| | - Ka Lun Lai
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong; Aptorum Therapeutics Limited, 17/F Guangdong Investment Tower, 148 Connaught Road Central, Hong Kong
| | - Qianying Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Wai Yip Thomas Lee
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong; Aptorum Group Limited, 17/F Guangdong Investment Tower, 148 Connaught Road Central, Hong Kong.
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6
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Zhang C, Xie H, Yang Q, Yang Y, Li W, Tian H, Lu L, Wang F, Xu JY, Gao F, Wang J, Jin C, Xu G, Xu GT, Zhang J. Erythropoietin protects outer blood-retinal barrier in experimental diabetic retinopathy by up-regulating ZO-1 and occludin. Clin Exp Ophthalmol 2019; 47:1182-1197. [PMID: 31483932 DOI: 10.1111/ceo.13619] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 08/25/2019] [Accepted: 08/26/2019] [Indexed: 01/29/2023]
Abstract
PURPOSE To explore the mechanisms of erythropoietin (EPO) in maintaining outer blood-retinal barrier (BRB) in diabetic rats. METHODS Sprague-Dawley rats were rendered diabetic with intraperitoneal injection of streptozotocin, and then followed by intravitreal injection of EPO. Two and four weeks later, the permeability of outer BRB was examined with FITC-dextran leakage assay, following a method to demarcate the inner and outer retina based on retinal blood supply. The glyoxal-treated ARPE-19 cells, incubated with EPO, soluble EPO receptor (sEPOR), Gö6976, or digoxin, were studied for cell viability and barrier function. The expressions of ZO-1, occludin, VEGFR2, HIF-1α, MAPKs, and AKT were examined with Western blot and immunofluorescence. RESULTS The major Leakage of FITC-dextran was detected in the outer nuclear layer in both 2- and 4-week diabetic rats. The leakage was largely ameliorated in EPO-treated diabetic rats. The protein expressions of ZO-1 and occludin in the RPE-Bruch's membrane choriocapillaris complex were significantly decreased, whereas HIF-1α and JNK pathways were activated, in 4-week diabetic rats. These changes were prevented by EPO treatment. The in vitro study with ARPE-19 cells confirmed these changes, and the protective effect of EPO was abolished by sEPOR. Gö6976 and digoxin rescued the tight junction and barrier function in glyoxal-treated ARPE-19 cells. CONCLUSIONS In early diabetic rats, the outer BRB might be more severely damaged and its breakdown is the major factor for retinal oedema. EPO maintains the outer BRB integrity through down-regulation of HIF-1α and JNK signallings, and thus up-regulating ZO-1 and occludin expressions in RPE cells.
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Affiliation(s)
- Chaoyang Zhang
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Hai Xie
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Qian Yang
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Yiting Yang
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Weiye Li
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China.,Department of Ophthalmology, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Haibin Tian
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Lixia Lu
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Fang Wang
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Jing-Ying Xu
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Furong Gao
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Juan Wang
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Caixia Jin
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Guoxu Xu
- Department of Ophthalmology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Guo-Tong Xu
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Jingfa Zhang
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pharmacology, Tongji University School of Medicine, Shanghai, China.,Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China.,National Center for Clinical Research of Ophthalmology, Shanghai, China
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Arthur E, Papay JA, Haggerty BP, Clark CA, Elsner AE. Subtle changes in diabetic retinas localised in 3D using OCT. Ophthalmic Physiol Opt 2018; 38:477-491. [PMID: 30051487 DOI: 10.1111/opo.12578] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/14/2018] [Indexed: 02/06/2023]
Abstract
PURPOSE To detect and localise subtle changes in retinas of diabetic patients who clinically have no diabetic retinopathy (DR) or non-proliferative DR (NPDR) as compared to age- and sex- matched controls. Spectral Domain Optical Coherence Tomography (SD-OCT) and software to examine all retinal layers, including deeper layers, were used to quantify foveal avascular zone size and inner and outer retinal layer thicknesses, as well as to detect axial location of prominent lesions. METHODS Diabetic subjects, 19 total with 16 having no DR and three having non-proliferative retinopathy, were matched with 19 controls with respect to age and sex. Macular-centred SD-OCT grids of 20 × 15° were taken with the Spectralis. En face or transverse images were generated from the SD-OCT data by automatically segmenting all retinal layers. The transverse images were investigated for foveal avascular zone (FAZ) size, retinal vessel calibre, and structural changes. The size of the FAZ was compared for diabetics vs controls using vendor software and manual marking in Photoshop. Inner retinal layer (IRLFAZ ) and outer nuclear layer (ONLFAZ ) thicknesses at the margins of the FAZ were measured using vendor software. RESULTS The FAZ area was larger for diabetics (mean ± S.D. = 0.388 ± 0.074 mm2 ) than controls (0.243 ± 0.113 mm2 ), t18 = 5.27, p < 0.0001, using vendor software. The mean IRLFAZ was thicker for the diabetics (86.8 ± 14.5 μm) than controls (65.2 ± 16.3 μm), t18 = 4.59, p = 0.00023, despite lack of exudation by clinical exam. There was no significant association between FAZ area and mean IRLFAZ for the diabetics, r = 0.099, p = 0.69. Vessels not clinically detected were visible in the NFL transverse image of most diabetics, especially for a mild NPDR patient. A prominent lesion found in the en face infra-red image of a mild NPDR subject was localised in the photoreceptor layer by SD-OCT, as well as additional outer retinal changes in other subjects. CONCLUSIONS Our results demonstrate changes in inner and outer diabetic retinas not readily detectable by clinical exam. IRLFAZ had not thinned at the margins of the large FAZs, indicating neural mass did not yet decrease despite potential ischemia.
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Affiliation(s)
- Edmund Arthur
- Indiana University School of Optometry, Bloomington, USA
| | - Joel A Papay
- Indiana University School of Optometry, Bloomington, USA
| | | | | | - Ann E Elsner
- Indiana University School of Optometry, Bloomington, USA
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8
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Prasad T, Roksnoer LCW, Zhu P, Verma A, Li Y, Batenburg WW, de Vries R, Danser AHJ, Li Q. Beneficial Effects of Combined AT1 Receptor/Neprilysin Inhibition (ARNI) Versus AT1 Receptor Blockade Alone in the Diabetic Eye. Invest Ophthalmol Vis Sci 2017; 57:6722-6730. [PMID: 27951594 PMCID: PMC5156511 DOI: 10.1167/iovs.16-20289] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose Dysfunction of the renin-angiotensin system (RAS) contributes to pathogenesis of diabetic retinopathy (DR). Yet RAS blockers have only limited beneficial effects on progression of DR in clinical trials. The natriuretic peptide system offsets RAS, so that enhancing the activity of this system on top of RAS blockade might be beneficial. Neprilysin has an important role in the degradation of natriuretic peptides. Therefore, we hypothesize that dual angiotensin receptor-neprilysin inhibition (ARNI) may outperform angiotensin receptor blocker (ARB) in protection against DR. We tested this hypothesis in streptozotocin-induced diabetic transgenic (mRen2)27 rats. Methods Adult male diabetic (mRen2)27 rats were followed for 5 or 12 weeks. Treatment with vehicle, irbesartan (ARB), or ARB combined with the neprilysin inhibitor thiorphan (irbesartan+thiorphan [ARNI]) occurred during the final 3 weeks. Retinal cell death, gliosis, and capillary loss were evaluated. Real-time polymerase chain reaction (RT-PCR) analyses were performed to quantify the retinal level of inflammatory cell markers. Results Both ARB- and ARNI-treated groups showed similarly reduced retinal apoptotic cell death, gliosis, and capillary loss compared to the vehicle-treated group in the 5-week study. Treatment with ARNI reduced the expression of inflammatory markers more than ARB treatment in the 5-week study. In the 12-week study, ARNI treatment showed significantly more reduction in apoptotic cell death (51% vs. 25% reduction), and capillary loss (68% vs. 43% reduction) than ARB treatment. Conclusions Treatment with ARNI provides better protection against DR in diabetic (mRen2)27 transgenic rats, compared to ARB alone. This approach may be a promising treatment option for patients with DR.
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Affiliation(s)
- Tuhina Prasad
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States
| | - Lodi C W Roksnoer
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Ping Zhu
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States
| | - Amrisha Verma
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States
| | - Yiming Li
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States
| | - Wendy W Batenburg
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - René de Vries
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - A H Jan Danser
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Qiuhong Li
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States
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9
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Desjardins DM, Yates PW, Dahrouj M, Liu Y, Crosson CE, Ablonczy Z. Progressive Early Breakdown of Retinal Pigment Epithelium Function in Hyperglycemic Rats. Invest Ophthalmol Vis Sci 2017; 57:2706-13. [PMID: 27191823 PMCID: PMC4874474 DOI: 10.1167/iovs.15-18397] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PURPOSE Diabetic macular edema (DME), an accumulation of fluid in the subretinal space, is a significant cause of vision loss. The impact of diabetes on the breakdown of the inner blood-retina barrier (BRB) is an established event that leads to DME. However, the role of the outer BRB in ocular diabetes has received limited attention. We present evidence that the breakdown of normal RPE function in hyperglycemia facilitates conditions conducive to DME pathogenesis. METHODS Brown Norway rats (130-150 g) were injected intraperitoneally with streptozotocin (STZ; 60 mg/kg) to induce hyperglycemia. After 4 weeks, Evans blue (EB) dye was injected intravenously to determine whether there was leakage of albumin into the retina. Subretinal saline blebs (0.5-1 μL) were placed 4 and 9 weeks after STZ injection, and time-lapse optical coherence tomography tracked the resorption rate. In a subset of rats, intravitreal bevacizumab, a humanized monoclonal antibody targeted to VEGF, was given at 5 weeks and resorption was measured at 9 weeks. RESULTS The ability of the RPE to transport fluid was reduced significantly after 4 and 9 weeks of hyperglycemia with a reduction of over 67% at 9 weeks. No EB dye leakage from inner retinal vessels was measured in hyperglycemic animals compared to control. The intravitreal administration of bevacizumab at week 5 significantly increased the rate of fluid transport in rats subjected to hyperglycemia for 9 weeks. CONCLUSIONS These results demonstrate that chronic hyperglycemia altered RPE fluid transport, in part dependent on the actions of VEGF. These results support the idea that RPE dysfunction is an early event associated with hyperglycemia that contributes to fluid accumulation in DME.
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10
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Abstract
PURPOSE To investigate whether cysts in diabetic macular edema are better visualized in the red channel of color fundus camera images, as compared with the green channel, because color fundus camera screening methods that emphasize short-wavelength light may miss cysts in patients with dark fundi or changes to outer blood retinal barrier. METHODS Fundus images for diabetic retinopathy photoscreening were acquired for a study with Aeon Imaging, EyePACS, University of California Berkeley, and Indiana University. There were 2047 underserved, adult diabetic patients, of whom over 90% self-identified as a racial/ethnic identify other than non-Hispanic white. Color fundus images at nominally 45 degrees were acquired with a Canon Cr-DGi non-mydriatic camera (Tokyo, Japan) then graded by an EyePACS certified grader. From the 148 patients graded to have clinically significant macular edema by the presence of hard exudates in the central 1500 μm of the fovea, we evaluated macular cysts in 13 patients with cystoid macular edema. Age ranged from 33 to 68 years. Color fundus images were split into red, green, and blue channels with custom Matlab software (Mathworks, Natick, MA). The diameter of a cyst or confluent cysts was quantified in the red-channel and green-channel images separately. RESULTS Cyst identification gave complete agreement between red-channel images and the standard full-color images. This was not the case for green-channel images, which did not expose cysts visible with standard full-color images in five cases, who had dark fundi. Cysts appeared more numerous and covered a larger area in the red channel (733 ± 604 μm) than in the green channel (349 ± 433 μm, P < .006). CONCLUSIONS Cysts may be underdetected with the present fundus camera methods, particularly when short-wavelength light is emphasized or in patients with dark fundi. Longer wavelength techniques may improve the detection of cysts and provide more information concerning the early stages of diabetic macular edema or the outer blood retinal barrier.
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11
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The role of natriuretic peptides in diabetes and its complications. Biomed Pharmacother 2016; 84:1826-1832. [PMID: 27832993 DOI: 10.1016/j.biopha.2016.10.089] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 10/06/2016] [Accepted: 10/30/2016] [Indexed: 12/15/2022] Open
Abstract
This review aimed to summarize recent findings on the role of natriuretic peptides (NPs) in diabetes and its important complications. Although the treatment of diabetes mellitus has benefited from recent advances, aggressive glycemic control can increase the risk of hypoglycemia and weight gain. Therefore, innovative therapies are required to address this issue. Natriuretic peptides (NPs) may have such novel therapeutic potential. NPs comprise a family of structurally related peptides, including atrial, brain, C-type, and dendroaspis. Each of these NPs has a wide range of specific functions to regulate and maintain cardiovascular, renal, and endocrine homeostasis. NPs exert their effects by interacting with three receptor subtypes including NPR-A, NPR-B, and NPR-C. The coronary NP system has been suggested to be involved in regulating water and salt balance, as well as vascular remodeling. In this review, we provide evidence that NPs play an important role in diabetes mellitus and its related complications including macrovascular and microvascular disorders. NPs hold promise as markers for early diagnosis, risk assessment, and intervention guidance in diabetes and its complications and may thus improve diabetes care.
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12
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Park SW, Kim JH, Park SM, Moon M, Lee KH, Park KH, Park WJ, Kim JH. RAGE mediated intracellular Aβ uptake contributes to the breakdown of tight junction in retinal pigment epithelium. Oncotarget 2016; 6:35263-73. [PMID: 26431165 PMCID: PMC4742103 DOI: 10.18632/oncotarget.5894] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/22/2015] [Indexed: 12/16/2022] Open
Abstract
Intracellular amyloid beta (Aβ) has been implicated in neuronal cell death in Alzheimer's disease (AD). Intracellular Aβ also contributes to tight junction breakdown of retinal pigment epithelium (RPE) in age-related macular degeneration (AMD). Although Aβ is predominantly secreted from neuronal cells, the mechanism of Aβ transport into RPE remains to be fully elucidated. In this study, we demonstrated that intracellular Aβ was found concomitantly with the breakdown of tight junction in RPE after subretinal injection of Aβ into the mouse eye. We also presented evidence that receptor for advanced glycation end products (RAGE) contributed to endocytosis of Aβ in RPE. siRNA-mediated knockdown of RAGE prevented intracellular Aβ accumulation as well as subsequent tight junction breakdown in RPE. In addition, we found that RAGE-mediated p38 MAPK signaling contributed to endocytosis of Aβ. Blockade of RAGE/p38 MAPK signaling inhibited Aβ endocytosis, thereby preventing tight junction breakdown in RPE. These results implicate that intracellular Aβ contributes to the breakdown of tight junction in RPE via the RAGE/p38 MAPK-mediated endocytosis. Thus, we suggest that RAGE could be a potential therapeutic target for intracellular Aβ induced outer BRB breakdown in AMD.
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Affiliation(s)
- Sung Wook Park
- Fight Against Angiogenesis-Related Blindness Laboratory, Biomedical Research Institute, Seoul National University Hospital, Jongno-gu, Seoul, Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Daehak-ro, Jongno-gu, Seoul, Korea
| | - Jin Hyoung Kim
- Fight Against Angiogenesis-Related Blindness Laboratory, Biomedical Research Institute, Seoul National University Hospital, Jongno-gu, Seoul, Korea
| | - Sang Min Park
- Department of Life Sciences, Life Sciences Concentration GIST (Gwangju Institute of Science and Technology), Cheomdan-gwagiro, Buk-gu, Gwangju, Korea
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Seo-gu, Daejeon, Korea
| | - Ki Hwang Lee
- Department of Ophthalmology, Ajou University School of Medicine, Yeongtong-gu, Suwon-si, Gyeonggi-do, Korea
| | - Kyu Hyung Park
- Department of Ophthalmology, College of Medicine, Seoul National University, Daehak-ro, Jongno-gu, Seoul, Korea.,Department of Ophthalmology, Seoul National University Bundang Hospital, Bundang-gu, Seongnam, Gyeonggi-do, Korea
| | - Woo Jin Park
- Department of Life Sciences, Life Sciences Concentration GIST (Gwangju Institute of Science and Technology), Cheomdan-gwagiro, Buk-gu, Gwangju, Korea
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness Laboratory, Biomedical Research Institute, Seoul National University Hospital, Jongno-gu, Seoul, Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Daehak-ro, Jongno-gu, Seoul, Korea.,Department of Ophthalmology, College of Medicine, Seoul National University, Daehak-ro, Jongno-gu, Seoul, Korea
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13
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Riddell N, Giummarra L, Hall NE, Crewther SG. Bidirectional Expression of Metabolic, Structural, and Immune Pathways in Early Myopia and Hyperopia. Front Neurosci 2016; 10:390. [PMID: 27625591 PMCID: PMC5003873 DOI: 10.3389/fnins.2016.00390] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/09/2016] [Indexed: 01/08/2023] Open
Abstract
Myopia (short-sightedness) affects 1.45 billion people worldwide, many of whom will develop sight-threatening secondary disorders. Myopic eyes are characterized by excessive size while hyperopic (long-sighted) eyes are typically small. The biological and genetic mechanisms underpinning the retina's local control of these growth patterns remain unclear. In the present study, we used RNA sequencing to examine gene expression in the retina/RPE/choroid across 3 days of optically-induced myopia and hyperopia induction in chick. Data were analyzed for differential expression of single genes, and Gene Set Enrichment Analysis (GSEA) was used to identify gene sets correlated with ocular axial length and refraction across lens groups. Like previous studies, we found few single genes that were differentially-expressed in a sign-of-defocus dependent manner (only BMP2 at 1 day). Using GSEA, however, we are the first to show that more subtle shifts in structural, metabolic, and immune pathway expression are correlated with the eye size and refractive changes induced by lens defocus. Our findings link gene expression with the morphological characteristics of refractive error, and suggest that physiological stress arising from metabolic and inflammatory pathway activation could increase the vulnerability of myopic eyes to secondary pathologies.
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Affiliation(s)
- Nina Riddell
- Department of Psychology and Counselling, La Trobe University Melbourne, VIC, Australia
| | - Loretta Giummarra
- Department of Psychology and Counselling, La Trobe University Melbourne, VIC, Australia
| | - Nathan E Hall
- Life Sciences Computation Centre, Victorian Life Sciences Computation InitiativeMelbourne, VIC, Australia; La Trobe UniversityMelbourne, VIC, Australia
| | - Sheila G Crewther
- Department of Psychology and Counselling, La Trobe University Melbourne, VIC, Australia
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14
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Dahrouj M, Desjardins DM, Liu Y, Crosson CE, Ablonczy Z. Receptor mediated disruption of retinal pigment epithelium function in acute glycated-albumin exposure. Exp Eye Res 2015; 137:50-6. [PMID: 26070987 PMCID: PMC4523492 DOI: 10.1016/j.exer.2015.06.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/12/2015] [Accepted: 06/08/2015] [Indexed: 12/22/2022]
Abstract
Diabetic macular edema (DME) is a major cause of visual impairment. Although DME is generally believed to be a microvascular disease, dysfunction of the retinal pigment epithelium (RPE) can also contribute to its development. Advanced glycation end-products (AGE) are thought to be one of the key factors involved in the pathogenesis of diabetes in the eye, and we have previously demonstrated a rapid breakdown of RPE function following glycated-albumin (Glyc-alb, a common AGE mimetic) administration in monolayer cultures of fetal human RPE cells. Here we present new evidence that this response is attributed to apically oriented AGE receptors (RAGE). Moreover, time-lapse optical coherence tomography in Dutch-belted rabbits 48 h post intravitreal Glyc-alb injections demonstrated a significant decrease in RPE-mediated fluid resorption in vivo. In both the animal and tissue culture models, the response to Glyc-alb was blocked by the relatively selective RAGE antagonist, FPS-ZM1 and was also inhibited by ZM323881, a relatively selective vascular endothelial growth factor receptor 2 (VEGF-R2) antagonist. Our data establish that the Glyc-alb-induced breakdown of RPE function is mediated via specific RAGE and VEGF-R2 signaling both in vitro and in vivo. These results are consistent with the notion that the RPE is a key player in the pathogenesis of DME.
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Affiliation(s)
- Mohammad Dahrouj
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425, United States
| | - Danielle M Desjardins
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425, United States
| | - Yueying Liu
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425, United States
| | - Craig E Crosson
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425, United States
| | - Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425, United States.
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15
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Aaltonen V, Kinnunen K, Jouhilahti EM, Peltonen J, Nikinmaa M, Kaarniranta K, Arjamaa O. Hypoxic conditions stimulate the release of B-type natriuretic peptide from human retinal pigment epithelium cell culture. Acta Ophthalmol 2014; 92:740-4. [PMID: 24739438 DOI: 10.1111/aos.12415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 03/09/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE A-type peptide, a natriuretic peptide belonging to the natriuretic peptide family, has been shown to be increased in the vitreous of patients suffering from diabetic retinopathy and that human retina has a well-developed natriuretic peptide system. The stimulus to which the synthesis of natriuretic peptides responded in these patients has, however, remained unknown. As the natriuretic peptides have recently been shown to respond to hypoxic conditions, the genes of both A-type and B-type have a hypoxia-response element (HRE) in their promoter sequence, we therefore hypothesized that hypoxia in the human retinal pigment epithelium will increase the secretion of NT-proBNP, the most common natriuretic peptide monitored in clinical medicine. METHODS We used cultured human retinal pigment epithelium cell line (ARPE-19) which was exposed either to normoxia or to hypoxia for 2 hr, 4 hr, 6 hr and 24 hr. NT-proBNP was measured with enzyme immunoassay, VEGF with ELISA and HIF-1α with Western blotting. RESULTS Hypoxia induced VEGF 165 release in culture medium and HIF-1α expression in cultured ARPE-19 cells. Time-dependent NT-proBNP release was detected when the ARPE-19 cells were cultured under normoxia. When hypoxia was induced, a statistically significant increase in NT-proBNP release was demonstrated in the culture medium. CONCLUSIONS Hypoxic conditions increase the release of a natriuretic peptide from retinal pigment epithelium (RPE) cells. The secretion of VEGF was also enhanced. The responses were associated with the up-regulation of the HIF-1α transcription factor. These results explain the previous findings from patients with diabetes, which also suggest that hypoxia is a ubiquitous stimulus for the secretion of natriuretic peptides in human body.
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Affiliation(s)
- Vesa Aaltonen
- Department of Ophthalmology; University Central Hospital; University of Turku; Turku Finland
- Department of Cell Biology and Anatomy; University of Turku; Turku Finland
| | - Kati Kinnunen
- Department of Ophthalmology; University of Eastern Finland; Kuopio Finland
| | | | - Juha Peltonen
- Department of Cell Biology and Anatomy; University of Turku; Turku Finland
| | - Mikko Nikinmaa
- Department of Biology; University of Turku; Turku Finland
| | - Kai Kaarniranta
- Department of Ophthalmology; University of Eastern Finland; Kuopio Finland
| | - Olli Arjamaa
- Department of Biology; University of Turku; Turku Finland
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16
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Paraoxonase enzyme protects retinal pigment epithelium from chlorpyrifos insult. PLoS One 2014; 9:e101380. [PMID: 24979751 PMCID: PMC4076322 DOI: 10.1371/journal.pone.0101380] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 06/05/2014] [Indexed: 12/21/2022] Open
Abstract
Retinal pigment epithelium (RPE) provides nourishment and protection to the eye. RPE dysfunction due to oxidative stress and inflammation is one of the major reason for many of the retinal disorders. Organophosphorus pesticides are widely used in the agricultural, industrial and household activities in India. However, their effects on the eye in the context of RPE has not been studied. In this study the defense of the ARPE19 cells exposed to Chlorpyrifos (1 nM to 100 µM) in terms of the enzyme paraoxonase (PON) was studied at 24 hr and 9 days of treatment. Chlorpyrifos was found to induce oxidative stress in the ARPE19 cells as seen by significant increase in ROS and decrease in glutathione (GSH) levels without causing cell death. Tissue resident Paraoxonase 2 (PON2) mRNA expression was elevated with chlorpyrifos exposure. The three enzymatic activities of PON namely, paraoxonase (PONase), arylesterase (PON AREase) and thiolactonase (PON HCTLase) were also found to be significantly altered to detoxify and as an antioxidant defense. Among the transcription factors regulating PON2 expression, SP1 was significantly increased with chlorpyrifos exposure. PON2 expression was found to be crucial as ARPE19 cells showed a significant loss in their ability to withstand oxidative stress when the cells were subjected to chlorpyrifos after silencing PON2 expression. Treatment with N-acetyl cysteine positively regulated the PON 2 expression, thus promoting the antioxidant defense put up by the cells in response to chlorpyrifos.
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17
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Kay P, Yang YC, Hiscott P, Gray D, Maminishkis A, Paraoan L. Age-related changes of cystatin C expression and polarized secretion by retinal pigment epithelium: potential age-related macular degeneration links. Invest Ophthalmol Vis Sci 2014; 55:926-34. [PMID: 24458156 PMCID: PMC11980428 DOI: 10.1167/iovs.13-13239] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Cystatin C, a potent cysteine proteinase inhibitor, is abundantly secreted by the RPE and may contribute to regulating protein turnover in the Bruch's membrane (BrM). A cystatin C variant associated with increased risk of developing AMD and Alzheimer's disease (AD) presents reduced secretion levels from RPE. The purpose of this study was to analyze the effects of age and the accumulation of advanced glycation end-products (AGEs) on the expression and secretion of cystatin C by the RPE. METHODS Confluent monolayers of human fetal RPE (hfRPE) cells were cultured using an in vitro model mimicking extracellular AGE accumulation. Cystatin C expression, secretion, and its polarity were analyzed following culture on AGE-containing BrM mimics (AGEd versus non-AGEd). Monolayer barrier properties were assessed by transepithelial resistance measurements. The relative level of cystatin C protein expression in human RPE in situ was assessed immunohistochemically in relation to age. RESULTS Advanced glycation end product-exposed RPE monolayers presented significantly decreased cystatin C expression and secretion. Basolateral secretion was fully established by week 8 in non-AGEd conditions. In AGEd cultures, polarity of secretion was impaired despite maintenance of physiological barrier properties of the monolayer. In the macula region of RPE/choroid segments from human eyes, the level of cystatin C protein was reduced with increasing donor age. CONCLUSIONS Exposure to AGEs reduces expression of cystatin C and affects its normal secretion in cultured RPE. Age-related changes of cystatin C in the RPE from the posterior pole may compromise its extracellular functions, potentially contributing to AMD pathogenesis.
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Affiliation(s)
- Paul Kay
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Yit C. Yang
- Department of Ophthalmology, The Royal Wolverhampton NHS Trust, Wolverhampton, United Kingdom
| | - Paul Hiscott
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Donna Gray
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | | | - Luminita Paraoan
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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