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Liu H, Zhang W, Lilly B. Evaluation of Notch3 Deficiency in Diabetes-Induced Pericyte Loss in the Retina. J Vasc Res 2018; 55:308-318. [PMID: 30347392 PMCID: PMC6280662 DOI: 10.1159/000493151] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/22/2018] [Indexed: 12/14/2022] Open
Abstract
Loss of vascular pericytes has long been associated with the onset of diabetic retinopathy; however, mechanisms contributing to pericyte dropout are not understood. Notch3 has been implicated in pericyte stability and survival, and linked to vascular integrity. Notch3 mutant mice exhibit progressive loss of retinal pericytes. Given that diabetic retinopathy is associated with pericyte loss, we sought to determine whether perturbation of Notch3 signaling contributes to diabetes-induced pericyte dropout and capillary degeneration. We utilized a pericyte-expressed LacZ transgene (XlacZ4) to examine pericyte loss in retinas of a type I diabetic mouse model (Ins2Akita) and Notch3-deficient mice. Notch3 null animals showed a dramatic loss of the LacZ marker by 8 weeks of age, while Ins2Akita diabetic and Notch3 heterozygous mice exhibited a much slower and subtler loss of LacZ. Although combined Notch3 heterozygosity in Ins2Akita diabetic animals did not show further deficits, the trypsin digest method revealed that Notch3 haploinsufficiency increased the formation of acellular capillaries in diabetic mice. Our data further indicate that Notch signaling is blunted in diabetic retinas and in cells exposed to hyperglycemia. These results are the first to demonstrate an association between Notch3 signaling, pericyte loss, and diabetic retinopathy.
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Affiliation(s)
- Hua Liu
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA
- Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, Texas, USA
| | - Wenbo Zhang
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA
- Departments of Neuroscience, Cell Biology and Anatomy, University of Texas Medical Branch, Galveston, Texas, USA
| | - Brenda Lilly
- Center for Cardiovascular Research, Columbus, Ohio,
- The Heart Center, Nationwide Children's Hospital, Columbus, Ohio,
- Department of Pediatrics, The Ohio State University, Columbus, Ohio,
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Reagan AM, Gu X, Paudel S, Ashpole NM, Zalles M, Sonntag WE, Ungvari Z, Csiszar A, Otalora L, Freeman WM, Stout MB, Elliott MH. Age-related focal loss of contractile vascular smooth muscle cells in retinal arterioles is accelerated by caveolin-1 deficiency. Neurobiol Aging 2018; 71:1-12. [PMID: 30059797 DOI: 10.1016/j.neurobiolaging.2018.06.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
Cerebral microcirculation is critical for the preservation of brain health, and vascular impairment is associated with age-related neurodegenerative diseases. Because the retina is a component of the central nervous system, cellular changes that occur in the aging retina are likely relevant to the aging brain, and the retina provides the advantage that the entire vascular bed is visible, en face. In this study, we tested the hypothesis that normal, healthy aging alters the contractile vascular smooth muscle cell (VSMC) coverage of retinal arterioles. We found that aging results in a significant reduction of contractile VSMCs in focal patches along arterioles. Focal loss of contractile VSMCs occurs at a younger age in mice deficient in the senescence-associated protein, caveolin-1. Age-related contractile VSMC loss is not exacerbated by genetic depletion of insulin-like growth factor-1. The patchy loss of contractile VSMCs provides a cellular explanation for previous clinical studies showing focal microirregularities in retinal arteriolar responsiveness in healthy aged human subjects and is likely to contribute to age-related retinal vascular complications.
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Affiliation(s)
- Alaina M Reagan
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Xiaowu Gu
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Sijalu Paudel
- Department of Cell Biology, Cameron University, Lawton, OK, USA
| | - Nicole M Ashpole
- Department of BioMolecular Sciences, University of Mississippi, Oxford, MS, USA
| | - Michelle Zalles
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - William E Sonntag
- Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zoltan Ungvari
- Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Anna Csiszar
- Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Laura Otalora
- Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Willard M Freeman
- Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael B Stout
- Department of Nutritional Sciences, University of Oklahoma Health Sciences Center, Oklahoma city, OK, USA
| | - Michael H Elliott
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Francis AW, Wanek J, Shahidi M. Assessment of Global and Local Alterations in Retinal Layer Thickness in Ins2 (Akita) Diabetic Mice by Spectral Domain Optical Coherence Tomography. J Ophthalmol 2018; 2018:7253498. [PMID: 29675273 PMCID: PMC5838457 DOI: 10.1155/2018/7253498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/24/2017] [Indexed: 12/27/2022] Open
Abstract
PURPOSE/AIM The Ins2 (Akita) mouse is a spontaneous diabetic mouse model with a heterozygous mutation in the insulin 2 gene that results in sustained hyperglycemia. The purpose of the study was to assess global and local retinal layer thickness alterations in Akita mice by analysis of spectral domain optical coherence tomography (SD-OCT) images. MATERIALS AND METHODS SD-OCT imaging was performed in Akita and wild-type mice at 12 and 24 weeks of age. Inner retinal thickness (IRT), outer retinal thickness (ORT), total retinal thickness (TRT), and photoreceptor outer segment length (OSL) were measured. Mean global thickness values were compared between Akita and wild-type mice. Local thickness variations in Akita mice were assessed based on normative values in wild-type mice. RESULTS Akita mice had higher blood glucose levels and lower body weights (p < 0.001). On average, IRT, ORT, and TRT were approximately 2% lower in Akita mice than in wild-type mice (p ≤ 0.02). In Akita mice, the percent difference between retinal areas with thickness below and above normative values for IRT, ORT, and TRT was 22%, 32%, and 38%, respectively. CONCLUSIONS These findings support the use of the Akita mouse model to study the retinal neurodegenerative effects of hyperglycemia.
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Affiliation(s)
- Andrew W. Francis
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Justin Wanek
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
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Gopinath G, Sankeshi V, perugu S, Alaparthi MD, Bandaru S, Pasala VK, Chittineni PR, Krupadanam G, Sagurthi SR. Design and synthesis of chiral 2 H -chromene- N -imidazolo-amino acid conjugates as aldose reductase inhibitors. Eur J Med Chem 2016; 124:750-762. [DOI: 10.1016/j.ejmech.2016.08.070] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 01/31/2023]
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Aldose reductase, ocular diabetic complications and the development of topical Kinostat®. Prog Retin Eye Res 2016; 54:1-29. [DOI: 10.1016/j.preteyeres.2016.04.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/11/2016] [Accepted: 04/14/2016] [Indexed: 12/20/2022]
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Activation of Melanocortin Receptors MC 1 and MC 5 Attenuates Retinal Damage in Experimental Diabetic Retinopathy. Mediators Inflamm 2016; 2016:7368389. [PMID: 26949291 PMCID: PMC4753692 DOI: 10.1155/2016/7368389] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/01/2015] [Accepted: 12/15/2015] [Indexed: 01/11/2023] Open
Abstract
We hypothesize that melanocortin receptors (MC) could activate tissue protective circuit in a model of streptozotocin- (STZ-) induced diabetic retinopathy (DR) in mice. At 12–16 weeks after diabetes induction, fluorescein angiography (FAG) revealed an approximate incidence of 80% microvascular changes, typical of DR, in the animals, without signs of vascular leakage. Occludin progressively decreased in the retina of mice developing retinopathy. qPCR of murine retina revealed expression of two MC receptors, Mc1r and Mc5r. The intravitreal injection (5 μL) of the selective MC1 small molecule agonist BMS-470539 (33 μmol) and the MC5 peptidomimetic agonist PG-901 (7.32 nM) elicited significant protection with regular course and caliber of retinal vessels, as quantified at weeks 12 and 16 after diabetes induction. Mouse retina homogenate settings indicated an augmented release of IL-1α, IL-1β, IL-6, MIP-1α, MIP-2α, MIP-3α, and VEGF from diabetic compared to nondiabetic mice. Application of PG20N or AGRP and MC5 and MC1 antagonist, respectively, augmented the release of cytokines, while the agonists BMS-470539 and PG-901 almost restored normal pattern of these mediators back to nondiabetic values. Similar changes were quantified with respect to Ki-67 staining. Finally, application of MC3-MC4 agonist/antagonists resulted to be inactive with respect to all parameters under assessment.
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Park J, Kim H, Park SY, Lim SW, Kim YS, Lee DH, Roh GS, Kim HJ, Kang SS, Cho GJ, Jeong BY, Kwon HM, Choi WS. Tonicity-responsive enhancer binding protein regulates the expression of aldose reductase and protein kinase C δ in a mouse model of diabetic retinopathy. Exp Eye Res 2014; 122:13-9. [PMID: 24631337 DOI: 10.1016/j.exer.2014.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/24/2014] [Accepted: 03/02/2014] [Indexed: 12/25/2022]
Abstract
Recent studies revealed that Tonicity-responsive enhancer binding protein (TonEBP) directly regulates the transcription of aldose reductase (AR), which catalyzes the first step of the polyol pathway of glucose metabolism. Activation of protein kinase C δ (PKCδ) is dependent on AR and it has been linked to diabetic complications. However, whether TonEBP affects expressions of AR and PKCδ in diabetic retinopathy was not clearly shown. In this study, we used TonEBP heterozygote mice to study the role of TonEBP in streptozotocin (STZ)-induced diabetic retinopathy. We performed immunofluorescence staining and found that retinal expressions of AR and PKCδ were significantly reduced in the heterozygotes compared to wild type littermates, particularly in ganglion cell layer. To examine further the effect of TonEBP reduction in retinal tissues, we performed intravitreal injection of TonEBP siRNA and confirmed the decrease in AR and PKCδ levels. In addition, we found that a proapoptotic factor, Bax level was reduced and a survival factor, Bcl2 level was increased after injection of TonEBP siRNA, indicating that TonEBP mediates apoptotic cell death. In parallel, TonEBP siRNA was applied to the in vitro human retinal pigment epithelial (ARPE-19) cells cultured in high glucose media. We have consistently found the decrease in AR and PKCδ levels and changes in apoptotic factors for survival. Together, these results clearly demonstrated that hyperglycemia-induced TonEBP plays a crucial role in increasing AR and PKCδ levels and leading to apoptotic death. Our findings suggest that TonEBP reduction is an effective therapeutic strategy for diabetic retinopathy.
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Affiliation(s)
- Jeongsook Park
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Department of Food & Nutrition, College of Natural Sciences, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Hwajin Kim
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - So Yun Park
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Sun Woo Lim
- Transplant Research Center, The of Catholic University of Korea, Seoul, Republic of Korea
| | - Yoon Sook Kim
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Dong Hoon Lee
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Gu Seob Roh
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Hyun Joon Kim
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Sang Soo Kang
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Gyeong Jae Cho
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | - Bo-Young Jeong
- Department of Food & Nutrition, College of Natural Sciences, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - H Moo Kwon
- School of Nano-Biotechnology and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Wan Sung Choi
- Department of Anatomy and Neurobiology, Institute of Health Science, Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
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Guo C, Zhang Z, Zhang P, Makita J, Kawada H, Blessing K, Kador PF. Novel transgenic mouse models develop retinal changes associated with early diabetic retinopathy similar to those observed in rats with diabetes mellitus. Exp Eye Res 2013; 119:77-87. [PMID: 24370601 DOI: 10.1016/j.exer.2013.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 12/11/2013] [Accepted: 12/16/2013] [Indexed: 12/13/2022]
Abstract
Retinal capillary pericyte degeneration has been linked to aldose reductase (AR) activity in diabetic retinopathy (DR). Since the development of DR in mice and rats has been reported to differ and that this may be linked to differences in retinal sorbitol levels, we have established new murine models of early onset diabetes mellitus as tools for investigating the role of AR in DR. Transgenic diabetic mouse models were developed by crossbreeding diabetic C57BL/6-Ins2(Akita)/J (AK) with transgenic C57BL mice expressing green fluorescent protein (GFP), human aldose reductase (hAR) or both in vascular tissues containing smooth muscle actin-α (SMAA). Changes in retinal sorbitol levels were determined by HPLC while changes of growth factors and signaling were investigated by Western Blots. Retinal vascular changes were quantitatively analyzed on elastase-digestion flat mounts. Results show that sorbitol levels were higher in neural retinas of diabetic AK-SMAA-GFP-hAR compared to AK-SMAA-GFP mice. AK-SMAA-GFP-hAR mice showed induction of the retinal growth factors VEGF, IGF-1, bFGF and TGFβ, as well as signaling changes in P-Akt, P-SAPK/JNK, and P-44/42 MAPK. Increased loss of nuclei per capillary length and a significant increase in the percentage of acellular capillaries presented in 18 week old AK-SMAA-GFP-hAR mice. These changes are similar to those observed in streptozotocin-induced diabetic rats. Retinal changes in both mice and rats were prevented by inhibition of AR. These studies confirm that the increased expression of AR in mice results in the development of retinal changes associated with the early stages of DR that are similar to those observed in rats.
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Affiliation(s)
- Changmei Guo
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Zifeng Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Peng Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Jun Makita
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Hiroyoshi Kawada
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Karen Blessing
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Peter F Kador
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA; Department of Ophthalmology, College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA.
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Wang X, Wang G, Kunte M, Shinde V, Gorbatyuk M. Modulation of angiogenesis by genetic manipulation of ATF4 in mouse model of oxygen-induced retinopathy [corrected]. Invest Ophthalmol Vis Sci 2013; 54:5995-6002. [PMID: 23942974 DOI: 10.1167/iovs.13-12117] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The activation of the unfolded protein response (UPR) and an increase in activating transcription factor 4 (ATF4) has been previously reported in the diabetic retina. Despite this, a direct link between ATF4 and the degree of proliferative retinopathy has not been demonstrated to date. Therefore, the objective of this study was to determine whether ATF4 deficiency could reduce neovascularization in mice with oxygen-induced retinopathy (OIR). METHODS We induced OIR in C57BL/6, ATF4(+/-), and endoplasmic reticulum stress-activated indicator (ERAI) mice and used quantitative RT-PCR and Western blot analysis to evaluate relative gene and protein expression. Histology and microscopy were used to calculate the extent of neovascularization in flat-mounted retinas. RESULTS Experimental data revealed Xbp1 splicing in the retinal ganglia cells, outer plexiform layer, inner nuclear layer, and outer nuclear layer and in pericytes of postdevelopment day 17 ERAI OIR mice, confirming the activation of IRE1 UPR signaling. In naive ATF4-deficient mice, we also observed an elevation in UPR-associated and vascular-associated gene expression (Bip, Atf6, Hif1a, Pik3/Akt, Flt1/Vegfa, and Tgfb1), which may have contributed to the alleviation of hypoxia-driven neovascularization in experimental ATF4(+/-) retinas. The OIR ATF4(+/-) retinas demonstrated reprogramming of the UPR seen at both the mRNA (Atf6 and Bip) and protein (pATF6 and peIf2α) levels, as well as a reduction in vascularization-associated gene expression (Flt1, Vegf1, Hif1, and Tgb1). These changes corresponded to the decline in the rate of neovascularization. CONCLUSIONS Our study validates ATF4 as a prospective therapeutic target to inhibit neovascularization in proliferative retinopathy.
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Affiliation(s)
- Xiaoqin Wang
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, Texas, USA
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Jadeja S, Mort RL, Keighren M, Hart AW, Joynson R, Wells S, Potter PK, Jackson IJ. A CNS-specific hypomorphic Pdgfr-beta mutant model of diabetic retinopathy. Invest Ophthalmol Vis Sci 2013; 54:3569-78. [PMID: 23633653 PMCID: PMC4025949 DOI: 10.1167/iovs.12-11125] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
PURPOSE A mouse mutant identified during a recessive N-ethyl-N-nitrosourea (ENU) mutagenesis screen exhibited ocular hemorrhaging resulting in a blood-filled orbit, and hence was named "redeye." We aimed to identify the causal mutation in redeye, and evaluate it as a model for diabetic retinopathy (DR). METHODS The causative gene mutation in redeye was identified by haplotype mapping followed by exome sequencing. Glucose tolerance tests, detailed histologic and immunofluorescence analyses, and vascular permeability assays were performed to determine the affect of redeye on glucose metabolism, pericyte recruitment, and the development of the retinal vasculature and blood-retinal barrier (BRB). RESULTS A mutation was identified in the Pdgfrb gene at position +2 of intron 6. We show that this change causes partial loss of normal splicing resulting in a frameshift and premature termination, and, therefore, a substantial reduction in normal Pdgfrb transcript. The animals exhibit defective pericyte recruitment restricted to the central nervous system (CNS) causing basement membrane and vascular patterning defects, impaired vascular permeability, and aberrant BRB development, resulting in vascular leakage and retinal ganglion cell apoptosis. Despite exhibiting classic features of diabetic retinopathy, redeye glucose tolerance is normal. CONCLUSIONS The Pdgfrb(redeye/redeye) mice exhibit all of the features of nonproliferative DR, including retinal neurodegeneration. In addition, the perinatal onset of the CNS-specific vascular phenotype negates the need to age animals or manage diabetic complications in other organs. Therefore, they are a more useful model for diseases involving pericyte deficiencies, such as DR, than those currently being used.
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Affiliation(s)
- Shalini Jadeja
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Richard L. Mort
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Margaret Keighren
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Alan W. Hart
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | | | | | | | - Ian J. Jackson
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
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