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Li JQ, Shi YH, Min-Xu, Shi CX, Teng-Wang, Wang TH, Zuo ZF, Liu XZ. Discovery of astragaloside IV against high glucose-induced apoptosis in retinal ganglion cells: Bioinformatics and in vitro studies. Gene 2024; 905:148219. [PMID: 38286267 DOI: 10.1016/j.gene.2024.148219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 01/31/2024]
Abstract
OBJECTIVE To examine the therapeutic mechanism of astragaloside IV (AS-IV) in the management of retinal ganglion cell (RGC) injury induced by high glucose (HG), a comprehensive approach involving the integration of network pharmacology and conducting in vitro and in vivo experiments was utilized. METHODS A rat model of diabetic retinopathy (DR) injury was created by administering streptozotocin through intraperitoneal injection. Additionally, a model of RGC injury induced by HG was established using a glucose concentration of 0.3 mmol/mL. Optical coherence tomography (OCT) images were captured 8 weeks after the injection of AS-IV. AS-IV and FBS were added to the culture medium and incubated for 48 h. The viability of cells was assessed using a CCK-8 assay, while the content of reactive oxygen species (ROS) was measured using DCFH-DA. Apoptosis was evaluated using Annexin V-PI. To identify the targets of AS-IV, hyperglycemia, and RGC, publicly available databases were utilized. The Metascape platform was employed for conducting GO and KEGG enrichment analyses. The STRING database in conjunction with Cytoscape 3.7.2 was used to determine common targets of protein-protein interactions (PPIs) and to identify the top 10 core target proteins in the RGC based on the MCC algorithm. qRT-PCR was used to measure the mRNA expression levels of the top10 core target proteins in RGCs. RESULTS OCT detection indicated that the thickness of the outer nucleus, and inner and outer accessory layers of the retina increased in the AS-IV treated retina compared to that in the DM group but decreased compared to that in the CON group. Coculturing RGC cells with AS-IV after HG induction resulted in a significant increase in cell viability and a decrease in ROS and apoptosis, suggesting that AS-IV can reduce damage to RGC cells caused by high glucose levels by inhibiting oxidative stress. There were 14 potential targets of AS-IV in the treatment of RGC damage induced by high glucose levels. The top 10 core target proteins identified by the MCC algorithm were HIF1α, AKT1, CTNNB1, SMAD2, IL6, SMAD3, IL1β, PPARG, TGFβ1, and NOTCH3. qRT-PCR analysis showed that AS-IV could upregulate the mRNA expression levels of SMAD3, TGF-β1, and NOTCH3, and downregulate the mRNA expression levels of HIF1α, AKT1, CTNNB1, SMAD2, SMAD3, and IL-1β in high glucose-induced RGC cells. CONCLUSION The findings of this study validate the efficacy of astragaloside IV in the treatment of DR and shed light on the molecular network involved. Specifically, HIF1α, AKT1, CTNNB1, SMAD2, SMAD3, and IL-1β were identified as the crucial candidate molecules responsible for the protective effects of astragaloside IV on RGCs.
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Affiliation(s)
- Jun-Qi Li
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University, Jinzhou, China; Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University, Jinzhou 121000, China
| | - Ya-Hui Shi
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University, Jinzhou, China; Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University, Jinzhou 121000, China
| | - Min-Xu
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University, Jinzhou, China; Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University, Jinzhou 121000, China
| | - Cai-Xing Shi
- School of Basic Medicine, Jining Medical University, Jining 272067, China
| | - Teng-Wang
- The First Affiliated Hospital of Jinzhou Medical University, 121000, China
| | - Ting-Hua Wang
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University, Jinzhou, China; Institute of Neuroscience, Kunming Medical University, Kunming 650500, China.
| | - Zhong-Fu Zuo
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University, Jinzhou, China; Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University, Jinzhou 121000, China.
| | - Xue-Zheng Liu
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University, Jinzhou, China; Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University, Jinzhou 121000, China.
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Li N, Guo XL, Xu M, Chen JL, Wang YF, Xiao YG, Gao AS, Zhang LC, Liu XZ, Wang TH. Network pharmacology mechanism of Scutellarin to inhibit RGC pyroptosis in diabetic retinopathy. Sci Rep 2023; 13:6504. [PMID: 37081038 PMCID: PMC10119430 DOI: 10.1038/s41598-023-33665-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 04/17/2023] [Indexed: 04/22/2023] Open
Abstract
To investigate the effect of scutellarin (SCU) in diabetic retinopathy (DR) and explore the associated molecular network mechanism. The animal model of DR was established from diabetic mellitus (DM) rats by intraperitoneally injected streptozotocin (STZ) at dosage 55 mg/kg. Meanwhile, SCU was intraperitoneally administrated to protect retina from cell pyroptosis induced by DM, and cell pyroptosis was detected by using HE, Nissl staining, and immunofluorescence recognition. Moreover, the hub gene involving in pyroptosis in DR was screened by bioinformatics and network pharmacology, designated as Venny intersection screen, GO and KEGG analysis, PPI protein interaction, and molecular docking. Lastly, the expressional change of hub genes were validated with experimental detection. Cell pyroptosis of the DR, specifically in retina ganglion cells (RGC), was induced in DM rats; SCU administration results in significant inhibition in the cell pyroptosis in DR. Mechanically, 4084 genes related to DR were screened from GeneCards and OMIM databases, and 120 SCU therapeutic targets were obtained, by using GeneCards, TCMSP with Swiss Target Prediction databases. Moreover, 357 targets related to pyroptosis were found using GenenCards database, and Drug, disease and phenotypic targets were analyzed online using the Draw Venn Diagram website, and 12 cross targets were obtained. Through GO function and KEGG pathway enrichment analysis, 659 BP related items, 7 CC related items, 30 MF related items, and 70 signal pathways were screened out; Of these, eleven proteins screened from cross-target PPI network were subsequently docked with the SCU, and their expressions including caspase-1, IL-1β, IL-18, GSDMD and NLRP3 in RGC indicated by immunofluorescence, and the mRNA expression for caspase-1 in DR indicated by quantitative PCR, were successfully validated. SCU can effectively protect RGC pyroptosis in DR, and underlying mechanisms are involved in the inhibition of caspase-1, GSDMD, NLRP3, IL-1β and IL-18. Our findings therefore provide crucial evidence to support the clinic practice of SCU for the treatment of DR, and explained the underlying molecular network mechanism.
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Affiliation(s)
- Na Li
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China
- Animal Center, Kunming Medical University, Kunming, 650500, China
| | - Xi-Liang Guo
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China
| | - Min Xu
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China
| | - Ji-Lin Chen
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China
- Animal Center, Kunming Medical University, Kunming, 650500, China
| | - Yu-Fei Wang
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China
| | - Yu-Gao Xiao
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China
| | - An-Shun Gao
- The First People's Hospital of Luquan Yi and Miao Autonomous County, Luquan, 651500, China
| | - Lan-Chun Zhang
- Animal Center, Kunming Medical University, Kunming, 650500, China.
| | - Xue-Zheng Liu
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China.
| | - Ting-Hua Wang
- Department of Anatomy, College of Basic Medicine, Jinzhou Medical University, Jinzhou, 121001, China.
- Animal Center, Kunming Medical University, Kunming, 650500, China.
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, China.
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Othman R, Cagnone G, Joyal JS, Vaucher E, Couture R. Kinins and Their Receptors as Potential Therapeutic Targets in Retinal Pathologies. Cells 2021; 10:1913. [PMID: 34440682 PMCID: PMC8391508 DOI: 10.3390/cells10081913] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 12/29/2022] Open
Abstract
The kallikrein-kinin system (KKS) contributes to retinal inflammation and neovascularization, notably in diabetic retinopathy (DR) and neovascular age-related macular degeneration (AMD). Bradykinin type 1 (B1R) and type 2 (B2R) receptors are G-protein-coupled receptors that sense and mediate the effects of kinins. While B2R is constitutively expressed and regulates a plethora of physiological processes, B1R is almost undetectable under physiological conditions and contributes to pathological inflammation. Several KKS components (kininogens, tissue and plasma kallikreins, and kinin receptors) are overexpressed in human and animal models of retinal diseases, and their inhibition, particularly B1R, reduces inflammation and pathological neovascularization. In this review, we provide an overview of the KKS with emphasis on kinin receptors in the healthy retina and their detrimental roles in DR and AMD. We highlight the crosstalk between the KKS and the renin-angiotensin system (RAS), which is known to be detrimental in ocular pathologies. Targeting the KKS, particularly the B1R, is a promising therapy in retinal diseases, and B1R may represent an effector of the detrimental effects of RAS (Ang II-AT1R).
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Affiliation(s)
- Rahmeh Othman
- School of Optometry, Université de Montréal, Montreal, QC H3T 1P1, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Gael Cagnone
- Department of Pediatry, Faculty of Medicine, CHU St Justine, Université de Montréal, Montreal, QC H3T 1J4, Canada; (G.C.); (J.-S.J.)
| | - Jean-Sébastien Joyal
- Department of Pediatry, Faculty of Medicine, CHU St Justine, Université de Montréal, Montreal, QC H3T 1J4, Canada; (G.C.); (J.-S.J.)
| | - Elvire Vaucher
- School of Optometry, Université de Montréal, Montreal, QC H3T 1P1, Canada
| | - Réjean Couture
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
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Kakaraparthi A, Godwin Potnuri A, Allakonda L. Beta 1 adrenoceptor blockade promotes angiogenesis in hypertrophied myocardium of transverse aortic constricted mice. Clin Exp Pharmacol Physiol 2021; 48:121-128. [PMID: 32750731 DOI: 10.1111/1440-1681.13389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 07/09/2020] [Accepted: 07/27/2020] [Indexed: 01/22/2023]
Abstract
Left ventricular hypertrophy (LVH) is an adaptive structural remodelling consequent to uncontrolled blood pressure. Impaired angiogenesis plays a vital role in transiting LVH into cardiac failure. Catecholamines modulate myocardial function through beta adrenoceptors, and their blockers (β-AR) reduce cardiovascular morbidity and mortality by decelerating the LVH progression. Nonetheless, the effect of β-AR blockers on myocardial vascular bed remains largely obscure. Hence, this study is focussed on analysing the possible outcomes of β-AR blockers on myocardial vascular remodelling using a surgically induced LVH mice model. Transverse aortic constricted mice and sham-operated mice were administered with metoprolol at a dose of 30 mg/kg/d for 60 days and myocardial vascular endothelial growth factor (VEGF) alpha levels, GSH/GSSG ratio, myocardial protein carbonyl content, hypertrophy index and global myocardial function, trans-aortic fluid dynamics and expression pattern of angiopoietin-1 and VEGF alpha were assessed. These findings were further confirmed by histochemical analysis for myocardial capillary density, perivascular fibrosis ratio and intimal thickening. Sub- chronic β-AR blockade reduced the oxidative stress, hypertrophic index, intimal thickening and perivascular fibrosis ratio. A marked increase in myocardial VEGF, angiopoietin 1, global myocardial function and myocardial capillary density was also observed. There was a reduction in the LVH and upregulation of myocardial angiogenesis concluding that β-AR blockers prevent adverse vascular remodelling which might underlie its concealed mechanism of action.
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Affiliation(s)
- Ajith Kakaraparthi
- Department of Pharmacology, Malla Reddy College of Pharmacy, Dhoolapally, Hyderabad, Telangana, India
| | - Ajay Godwin Potnuri
- Department of Animal Physiology and Pharmacology, ICMR-National Animal Resource Facility for Biomedical Research, Genome Valley, Shamirpet, Hyderabad, Telangana, India
| | - Lingesh Allakonda
- Department of Pharmacology, G. Pulla Reddy College of Pharmacy, Mehadipatnam, Hyderabad, Telangana, India
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Othman R, Vaucher E, Couture R. Bradykinin Type 1 Receptor - Inducible Nitric Oxide Synthase: A New Axis Implicated in Diabetic Retinopathy. Front Pharmacol 2019; 10:300. [PMID: 30983997 PMCID: PMC6449803 DOI: 10.3389/fphar.2019.00300] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/11/2019] [Indexed: 12/15/2022] Open
Abstract
Compelling evidence suggests a role for the inducible nitric oxide synthase, iNOS, and the bradykinin type 1 receptor (B1R) in diabetic retinopathy, including a possible control of the expression and activity of iNOS by B1R. In diabetic retina, both iNOS and B1R contribute to inflammation, oxidative stress, and vascular dysfunction. The present study investigated whether inhibition of iNOS has any impact on inflammatory/oxidative stress markers and on the B1R-iNOS expression, distribution, and action in a model of type I diabetes. Diabetes was induced in 6-week-old Wistar rats by streptozotocin (65 mg.kg-1, i.p.). The selective iNOS inhibitor 1400W (150 μg.10 μl-1) was administered twice a day by eye-drops during the second week of diabetes. The retinae were collected 2 weeks after diabetes induction to assess the protein and gene expression of markers by Western blot and qRT-PCR, the distribution of iNOS and B1R by fluorescence immunocytochemistry, and the vascular permeability by the Evans Blue dye technique. Diabetic retinae showed enhanced expression of iNOS, B1R, carboxypeptidase M (involved in the biosynthesis of B1R agonists), IL-1β, TNF-α, vascular endothelium growth factor A (VEGF-A) and its receptor, VEGF-R2, nitrosylated proteins and increased vascular permeability. All those changes were reversed by treatment with 1400W. Moreover, the additional increase in vascular permeability in diabetic retina induced by intravitreal injection of R-838, a B1R agonist, was also prevented by 1400W. Immunofluorescence staining highlighted strong colocalization of iNOS and B1R in several layers of the diabetic retina, which was prevented by 1400W. This study suggests a critical role for iNOS and B1R in the early stage of diabetic retinopathy. B1R and iNOS appear to partake in a mutual auto-induction and amplification loop to enhance nitrogen species formation and inflammation in diabetic retina. Hence, B1R-iNOS axis deserves closer scrutiny in targeting diabetic retinopathy.
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Affiliation(s)
- Rahmeh Othman
- School of Optometry, University of Montreal, Montreal, QC, Canada.,Department of Pharmacology and Physiology, University of Montreal, Montreal, QC, Canada
| | - Elvire Vaucher
- School of Optometry, University of Montreal, Montreal, QC, Canada
| | - Réjean Couture
- Department of Pharmacology and Physiology, University of Montreal, Montreal, QC, Canada
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Malek G, Busik J, Grant MB, Choudhary M. Models of retinal diseases and their applicability in drug discovery. Expert Opin Drug Discov 2018; 13:359-377. [PMID: 29382242 DOI: 10.1080/17460441.2018.1430136] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The impact of vision debilitating diseases is a global public health concern, which will continue until effective preventative and management protocols are developed. Two retinal diseases responsible for the majority of vision loss in the working age adults and elderly populations are diabetic retinopathy (DR) and age-related macular degeneration (AMD), respectively. Model systems, which recapitulate aspects of human pathology, are valid experimental modalities that have contributed to the identification of signaling pathways involved in disease development and consequently potential therapies. Areas covered: The pathology of DR and AMD, which serve as the basis for designing appropriate models of disease, is discussed. The authors also review in vitro and in vivo models of DR and AMD and evaluate the utility of these models in exploratory and pre-clinical studies. Expert opinion: The complex nature of non-Mendelian diseases such as DR and AMD has made identification of effective therapeutic treatments challenging. However, the authors believe that while in vivo models are often criticized for not being a 'perfect' recapitulation of disease, they have been valuable experimentally when used with consideration of the strengths and limitations of the experimental model selected and have a place in the drug discovery process.
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Affiliation(s)
- Goldis Malek
- a Department of Ophthalmology , Duke University School of Medicine , Durham , NC , USA.,b Department of Pathology , Duke University School of Medicine , Durham , NC , USA
| | - Julia Busik
- c Department of Physiology , Michigan State University , East Lansing , MI , USA
| | - Maria B Grant
- d Department of Ophthalmology , University of Alabama at Birmingham , Birmingham , Al , USA
| | - Mayur Choudhary
- a Department of Ophthalmology , Duke University School of Medicine , Durham , NC , USA
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Hein TW, Xu W, Xu X, Kuo L. Acute and Chronic Hyperglycemia Elicit JIP1/JNK-Mediated Endothelial Vasodilator Dysfunction of Retinal Arterioles. Invest Ophthalmol Vis Sci 2017; 57:4333-40. [PMID: 27556216 PMCID: PMC5015966 DOI: 10.1167/iovs.16-19990] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Hyperglycemia, a hallmark of diabetes mellitus, is associated with retinal inflammation and impairment of endothelium-dependent nitric oxide (NO)–mediated dilation of retinal arterioles. However, molecular mechanisms involved in this diminished endothelial vasodilator function remain unclear. We examined whether inflammatory stress-activated kinases, c-Jun N-terminal kinase (JNK) and p38, contribute to retinal arteriolar dysfunction during exposure to acute and chronic hyperglycemia. Methods Retinal arterioles were isolated from streptozocin-induced diabetic pigs (2 weeks; chronic hyperglycemia, 471 ± 23 mg/dL) or age-matched control pigs (euglycemia, 79 ± 5 mg/dL), and then cannulated and pressurized for vasoreactivity study. For acute hyperglycemia study, vessels from nondiabetic pigs were exposed intraluminally to high glucose (25 mM ≈ 450 mg/dL) for 2 hours, and normal glucose (5 mM ≈ 90 mg/dL) served as the control. Results Endothelium-dependent vasodilation to bradykinin was reduced in a similar manner after exposure to acute or chronic hyperglycemia. Administration of NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) nearly abolished vasodilations either in control (euglycemia and normal glucose) or hyperglycemic (acute and chronic) vessels. Treatment of either acute or chronic hyperglycemic vessels with JNK inhibitor SP600125 or JNK-interacting protein-1 (JIP1) inhibitor BI-78D3, but not p38 inhibitor SB203580, preserved bradykinin-induced dilation in an L-NAME–sensitive manner. By contrast, endothelium-independent vasodilation to sodium nitroprusside was unaffected by acute or chronic hyperglycemia. Conclusions Activation of JIP1/JNK signaling in retinal arterioles during exposure to acute or chronic hyperglycemia leads to selective impairment of endothelium-dependent NO-mediated dilation. Therapeutic targeting of the vascular JNK pathway may improve retinal endothelial vasodilator function during early diabetes.
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Affiliation(s)
- Travis W Hein
- Department of Surgery, Baylor Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Wenjuan Xu
- Department of Surgery, Baylor Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Xin Xu
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Lih Kuo
- Department of Surgery, Baylor Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States 2Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
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de Moraes G, Layton CJ. Therapeutic targeting of diabetic retinal neuropathy as a strategy in preventing diabetic retinopathy. Clin Exp Ophthalmol 2016; 44:838-852. [PMID: 27334889 DOI: 10.1111/ceo.12795] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/22/2016] [Accepted: 06/16/2016] [Indexed: 12/21/2022]
Abstract
Diabetes causes a panretinal neurodegeneration herein termed diabetic retinal neuropathy, which manifests in the retina early and progresses throughout the disease. Clinical manifestations include changes in the ERG, perimetry, dark adaptation, contrast sensitivity and colour vision which correlate with laboratory findings of thinning of the retinal neuronal layers, increased apoptosis in neurons and activation of glial cells. Possible mechanisms include oxidative stress, neuronal AGE accumulation, altered balance of neurotrophic factors and loss of mitohormesis. Retinal neural damage precedes and is a biologically plausible cause of retinal vasculopathy later in diabetes, and this review suggests that strategies to target it directly could prevent diabetes induced blindness. The efficacy of fenofibrate in reducing retinopathy progression provides a possible proof of concept for this approach. Strategies which may target diabetic retinal neuropathy include reducing retinal metabolic demand, improving mitochondrial function with AMPK and Sirt1 activators or providing neurotrophic support with neurotrophic supplementation.
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Affiliation(s)
| | - Christopher J Layton
- Gallipoli Medical Research Foundation, Brisbane, Queensland, Australia.,University of Queensland School of Medicine, Brisbane, Queensland, Australia.,Greenslopes Private Hospital Ophthalmology Department, Greenslopes Hospital, Brisbane, Queensland, Australia
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El-Hadidy AR, El-Mohandes EM, Asker SA, Ghonaim FM. A histological and immunohistochemical study of the effects of N-acetyl cysteine on retinopathy of prematurity by modifying insulin-like growth factor-1. Biotech Histochem 2016; 91:401-11. [PMID: 27149563 DOI: 10.1080/10520295.2016.1180428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Retinopathy of prematurity (ROP) is a vasoproliferative disorder that occurs in premature infants and may lead to permanent visual impairment. We investigated both the possible protective role of N-acetyl cysteine (NAC) for preventing ROP and the role of IGF-1 in the disorder. Forty-five newborn rats were divided into three groups. Group 1 was raised in room air as controls. Group 2 was exposed to 60% oxygen for 14 days after birth, then transferred to room air. Group 3 was exposed to the same conditions as group 2, but received intraperitoneal injections of NAC on postnatal days 7-17. After 35 days, both eyes of all rats were processed for histology. Some sections were stained with hematoxylin and eosin to assess structural changes and other sections were immunostained to determine the location of IGF-1. Frozen sections also were prepared and stained for adenosine triphosphatase to detect retinal blood vessels. Compared to the controls, more blood vessels, many of which were abnormal, and increased IGF-1 expression were observed in group 2. In group 3, abnormal blood vessels and IGF-1 expression were less evident. NAC appeared to be an effective vascular-protective agent for ROP by decreasing IGF-1 expression.
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Affiliation(s)
- A R El-Hadidy
- a Histology and Cell Biology Department, Faculty of Medicine , Mansoura University , Mansoura , Egypt
| | - E M El-Mohandes
- a Histology and Cell Biology Department, Faculty of Medicine , Mansoura University , Mansoura , Egypt
| | - S A Asker
- a Histology and Cell Biology Department, Faculty of Medicine , Mansoura University , Mansoura , Egypt
| | - F M Ghonaim
- a Histology and Cell Biology Department, Faculty of Medicine , Mansoura University , Mansoura , Egypt
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Tie G, Yan J, Messina JA, Raffai RL, Messina LM. Inhibition of p38 Mitogen-Activated Protein Kinase Enhances the Apoptosis Induced by Oxidized Low-Density Lipoprotein in Endothelial Progenitor Cells. J Vasc Res 2016; 52:361-71. [PMID: 27031525 DOI: 10.1159/000443889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 01/10/2016] [Indexed: 11/19/2022] Open
Abstract
Oxidized low-density lipoprotein (oxLDL) is an important risk factor in the development of atherosclerosis. oxLDL has been shown to decrease endothelial progenitor cell (EPC) number by inducing apoptosis. p38 mitogen-activated protein kinase (MAPK) was shown to be activated by oxLDL and participated in the regulation of EPC number and function. However, the role of p38 remains unknown. Here, we show that oxLDL-induced p38 phosphorylation in EPCs is time and dose dependent. Treatment with antioxidant N-acetyl cysteine restored oxLDL-induced p38 phosphorylation to basal levels. LOX-1-blocking antibody also significantly decreased oxLDL-induced p38 phosphorylation. Interestingly, TUNEL staining showed that pretreatment with the p38 inhibitor SB203580 further increased oxLDL-induced apoptosis in EPCs. In accordance with these findings, pretreatment with SB203580 further attenuated Akt phosphorylation in EPCs challenged with oxLDL, indicating an interaction between Akt and p38 MAPK pathways. In agreement, inhibition of p38 MAPK further attenuated Akt phosphorylation and increased apoptosis in EPCs isolated from hypercholesterolemic ApoE-/- mice. In conclusion, p38 MAPK serves as an anti-apoptotic pathway by supporting Akt activity when EPCs are challenged with oxLDL.
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Affiliation(s)
- Guodong Tie
- Division of Vascular Surgery, University of Massachusetts Medical School, Worcester, Mass., USA
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Zaitseva II, Berggren PO, Zaitsev SV. Insulinotropic compounds decrease endothelial cell survival. Toxicol In Vitro 2016; 33:1-8. [PMID: 26883446 DOI: 10.1016/j.tiv.2016.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 01/05/2016] [Accepted: 02/10/2016] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Hyperglycemia induces damage of vascular endothelial cells leading to diabetic complications. We investigated the effects of insulinotropic compounds and elevated glucose on endothelial cells in the absence or presence of vascular endothelial growth factor (VEGF). RESULTS Human umbilical vein endothelial cells (HUVECs) were treated with glibenclamide, repaglinide and insulinotropic imidazolines at high glucose concentration in the presence or absence of VEGF and viability, proliferation and nitric oxide production were measured. Hyperglycemia inhibited pro-survival effects of VEGF on endothelial cells. Glibenclamide and repaglinide decreased HUVEC viability at elevated glucose concentration in the absence but not in the presence of VEGF, without affecting HUVEC proliferation. Repaglinide also had some positive influence on HUVEC function elevating NO production in the presence of VEGF. Imidazolines showed different activities on endothelial cell survival. Efaroxan diminished HUVEC viability at elevated glucose concentration in the presence, however not in the absence of VEGF, while RX871024 decreased HUVEC survival regardless of the presence of VEGF. SIGNIFICANCE OF THE STUDY Our data demonstrate an important interplay between the actual insulinotropic compounds, VEGF and ambient glucose concentration affecting the survival of the vascular endothelial cells. Consequently, this interplay needs to be taken into consideration when designing novel oral antidiabetic compounds.
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Affiliation(s)
- Irina I Zaitseva
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Per-Olof Berggren
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Sergei V Zaitsev
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-17176 Stockholm, Sweden; Lomonosov Moscow State University, Belozersky Institute of Physico-chemical Biology, Faculty of Bioengineering and Bioinformatics, Moscow 119992, Russia.
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Hernández C, Dal Monte M, Simó R, Casini G. Neuroprotection as a Therapeutic Target for Diabetic Retinopathy. J Diabetes Res 2016; 2016:9508541. [PMID: 27123463 PMCID: PMC4830713 DOI: 10.1155/2016/9508541] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/29/2016] [Accepted: 03/16/2016] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy (DR) is a multifactorial progressive disease of the retina and a leading cause of vision loss. DR has long been regarded as a vascular disorder, although neuronal death and visual impairment appear before vascular lesions, suggesting an important role played by neurodegeneration in DR and the appropriateness of neuroprotective strategies. Upregulation of vascular endothelial growth factor (VEGF), the main target of current therapies, is likely to be one of the first responses to retinal hyperglycemic stress and VEGF may represent an important survival factor in early phases of DR. Of central importance for clinical trials is the detection of retinal neurodegeneration in the clinical setting, and spectral domain optical coherence tomography seems the most indicated technique. Many substances have been tested in animal studies for their neuroprotective properties and for possible use in humans. Perhaps, the most intriguing perspective is the use of endogenous neuroprotective substances or nutraceuticals. Together, the data point to the central role of neurodegeneration in the pathogenesis of DR and indicate neuroprotection as an effective strategy for treating this disease. However, clinical trials to determine not only the effectiveness and safety but also the compliance of a noninvasive route of drug administration are needed.
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Affiliation(s)
- Cristina Hernández
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabolicas Asociadas) and Diabetes and Metabolism Research Unit, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autonoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
- *Cristina Hernández: and
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Rafael Simó
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabolicas Asociadas) and Diabetes and Metabolism Research Unit, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autonoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
| | - Giovanni Casini
- Department of Biology, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
- *Giovanni Casini:
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Thirunavukkarasu M, Selvaraju V, Tapias L, Sanchez JA, Palesty JA, Maulik N. Protective effects of Phyllanthus emblica against myocardial ischemia-reperfusion injury: the role of PI3-kinase/glycogen synthase kinase 3β/β-catenin pathway. J Physiol Biochem 2015; 71:623-33. [DOI: 10.1007/s13105-015-0426-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/31/2015] [Indexed: 01/16/2023]
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Exploring the various aspects of the pathological role of vascular endothelial growth factor (VEGF) in diabetic retinopathy. Pharmacol Res 2015; 99:137-48. [DOI: 10.1016/j.phrs.2015.05.013] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/30/2015] [Accepted: 05/31/2015] [Indexed: 12/13/2022]
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Elgayar SAM, Eltony SA, Sayed AA, Abdel-Rouf MM. Genistein Treatment Confers Protection against Gliopathy and Vasculopathy of the Diabetic Retina in Rats. Ultrastruct Pathol 2015; 39:385-94. [PMID: 26548435 DOI: 10.3109/01913123.2015.1045664] [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] [Indexed: 11/13/2022]
Abstract
Retinopathy remains an important complication of diabetes. This work was carried out to evaluate the protective effects of genistein from diabetic retinopathy in rat. Fifteen adult male albino rats were divided into two groups; Group I: control (n = 5) and Group II: streptozotocin induced diabetic group (n = 10), which is equally divided into two subgroups; IIa (diabetic vehicle control) and IIb (diabetic genistein-treated). Specimens were taken from the retina 12 weeks post induction, processed and examined using light, immunohistochemical, ultrastructural techniques. Blood samples were assayed for the levels of glucose. In comparison with the diabetic non-treated group, the histological changes in macro and microglial glial cells reactivity and retinal blood capillaries were improved in genistein-treated groups. In addition, GFAP and iNOS expressions in the retina and the blood glucose level were reduced. Genistein ameliorates the histological changes of diabetic retinopathy reaching healing features, which resemble that of a normal retina.
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Affiliation(s)
- Sanaa A M Elgayar
- a Department of Histology, Faculty of Medicine , Assiut University , Assiut , Egypt
| | - Sohair A Eltony
- a Department of Histology, Faculty of Medicine , Assiut University , Assiut , Egypt
| | - Abdelrahman A Sayed
- a Department of Histology, Faculty of Medicine , Assiut University , Assiut , Egypt
| | - Maha M Abdel-Rouf
- a Department of Histology, Faculty of Medicine , Assiut University , Assiut , Egypt
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Coucha M, Elshaer SL, Eldahshan WS, Mysona BA, El-Remessy AB. Molecular mechanisms of diabetic retinopathy: potential therapeutic targets. Middle East Afr J Ophthalmol 2015; 22:135-44. [PMID: 25949069 PMCID: PMC4411608 DOI: 10.4103/0974-9233.154386] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults in United States. Research indicates an association between oxidative stress and the development of diabetes complications. However, clinical trials with general antioxidants have failed to prove effective in diabetic patients. Mounting evidence from experimental studies that continue to elucidate the damaging effects of oxidative stress and inflammation in both vascular and neural retina suggest its critical role in the pathogenesis of DR. This review will outline the current management of DR as well as present potential experimental therapeutic interventions, focusing on molecules that link oxidative stress to inflammation to provide potential therapeutic targets for treatment or prevention of DR. Understanding the biochemical changes and the molecular events under diabetic conditions could provide new effective therapeutic tools to combat the disease.
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Affiliation(s)
- Maha Coucha
- Department of Clinical Pharmacy, Program in Clinical and Experimental Therapeutics, University of Georgia, Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University, Georgia, USA ; Research Service, Charlie Norwood VA Medical Center, Augusta 30912, Georgia, USA
| | - Sally L Elshaer
- Department of Clinical Pharmacy, Program in Clinical and Experimental Therapeutics, University of Georgia, Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University, Georgia, USA ; Research Service, Charlie Norwood VA Medical Center, Augusta 30912, Georgia, USA
| | - Wael S Eldahshan
- Department of Clinical Pharmacy, Program in Clinical and Experimental Therapeutics, University of Georgia, Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University, Georgia, USA ; Research Service, Charlie Norwood VA Medical Center, Augusta 30912, Georgia, USA
| | - Barbara A Mysona
- Department of Clinical Pharmacy, Program in Clinical and Experimental Therapeutics, University of Georgia, Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University, Georgia, USA ; Research Service, Charlie Norwood VA Medical Center, Augusta 30912, Georgia, USA
| | - Azza B El-Remessy
- Department of Clinical Pharmacy, Program in Clinical and Experimental Therapeutics, University of Georgia, Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University, Georgia, USA ; Research Service, Charlie Norwood VA Medical Center, Augusta 30912, Georgia, USA
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Shanab AY, Mysona BA, Matragoon S, El-Remessy AB. Silencing p75(NTR) prevents proNGF-induced endothelial cell death and development of acellular capillaries in rat retina. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2015; 2:15013. [PMID: 26029724 PMCID: PMC4445004 DOI: 10.1038/mtm.2015.13] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 02/12/2015] [Accepted: 02/13/2015] [Indexed: 12/12/2022]
Abstract
Accumulation of the nerve growth factor precursor (proNGF) and its receptor p75(NTR) have been associated with several neurodegenerative diseases in both brain and retina. However, whether proNGF contributes to microvascular degeneration remain unexplored. This study seeks to investigate the mechanism by which proNGF/p75(NTR) induce endothelial cell (EC) death and development of acellular capillaries, a surrogate marker of retinal ischemia. Stable overexpression of the cleavage-resistant proNGF and molecular silencing of p75(NTR) were utilized in human retinal EC and rat retinas in vivo. Stable overexpression of proNGF decreased NGF levels and induced retinal vascular cell death evident by 1.9-fold increase in acellular capillaries and activation of JNK and cleaved-PARP that were mitigated by p75(NTR)shRNA. In vitro, overexpression of proNGF did not alter TNF-α level, reduced NGF, however induced EC apoptosis evident by activation of JNK and p38 MAPK, cleaved-PARP. Silencing p75(NTR) using siRNA restored expression of NGF and TrkA activation and prevented EC apoptosis. Treatment of EC with human-mutant proNGF induced apoptosis that coincided with marked protein interaction and nuclear translocation of p75(NTR) and the neurotrophin receptor interacting factor. These effects were abolished by a selective p75(NTR) antagonist. Therefore, targeting p75(NTR) represents a potential therapeutic strategy for diseases associated with aberrant expression of proNGF.
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Affiliation(s)
- Ahmed Y Shanab
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia , Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University , Georgia, USA ; Charlie Norwood Veterans Affairs Medical Center , Augusta, Georgia, USA
| | - Barbara A Mysona
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia , Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University , Georgia, USA ; Charlie Norwood Veterans Affairs Medical Center , Augusta, Georgia, USA
| | - Suraporn Matragoon
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia , Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University , Georgia, USA ; Charlie Norwood Veterans Affairs Medical Center , Augusta, Georgia, USA
| | - Azza B El-Remessy
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia , Georgia, USA ; Culver Vision Discovery Institute, Georgia Regents University , Georgia, USA ; Charlie Norwood Veterans Affairs Medical Center , Augusta, Georgia, USA
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Abdelsaid M, Prakash R, Li W, Coucha M, Hafez S, Johnson MH, Fagan SC, Ergul A. Metformin treatment in the period after stroke prevents nitrative stress and restores angiogenic signaling in the brain in diabetes. Diabetes 2015; 64:1804-17. [PMID: 25524911 PMCID: PMC4407857 DOI: 10.2337/db14-1423] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/11/2014] [Indexed: 12/04/2022]
Abstract
Diabetes impedes vascular repair and causes vasoregression in the brain after stroke, but mechanisms underlying this response are still unclear. We hypothesized that excess peroxynitrite formation in diabetic ischemia/reperfusion (I/R) injury inactivates the p85 subunit of phosphoinositide 3-kinase (PI3K) by nitration and diverts the PI3K-Akt survival signal to the p38-mitogen-activated protein kinase apoptosis pathway. Nitrotyrosine (NY), Akt and p38 activity, p85 nitration, and caspase-3 cleavage were measured in brains from control, diabetic (GK), or metformin-treated GK rats subjected to sham or stroke surgery and in brain microvascular endothelial cells (BMVECs) from Wistar and GK rats subjected to hypoxia/reoxygenation injury. GK rat brains showed increased NY, caspase-3 cleavage, and p38 activation and decreased Akt activation. Metformin attenuated stroke-induced nitrative signaling in GK rats. GK rat BMVECs showed increased basal nitrative stress compared with controls. A second hit by hypoxia/reoxygenation injury dramatically increased the nitration of p85 and activation of p38 but decreased Akt. These effects were associated with impairment of angiogenic response and were restored by treatment with the peroxynitrite scavenger 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron III chloride or the nitration inhibitor epicatechin. Our results provide evidence that I/R-induced peroxynitrite inhibits survival, induces apoptosis, and promotes peroxynitrite as a novel therapeutic target for the improvement of reparative angiogenesis after stroke in diabetes.
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Affiliation(s)
- Mohammed Abdelsaid
- Charlie Norwood Veterans Administration Medical Center, Augusta, GA Department of Physiology, Georgia Regents University, Augusta, GA
| | - Roshini Prakash
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA
| | - Weiguo Li
- Charlie Norwood Veterans Administration Medical Center, Augusta, GA Department of Physiology, Georgia Regents University, Augusta, GA
| | - Maha Coucha
- Department of Physiology, Georgia Regents University, Augusta, GA
| | - Sherif Hafez
- Charlie Norwood Veterans Administration Medical Center, Augusta, GA Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA
| | | | - Susan C Fagan
- Charlie Norwood Veterans Administration Medical Center, Augusta, GA Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA
| | - Adviye Ergul
- Charlie Norwood Veterans Administration Medical Center, Augusta, GA Department of Physiology, Georgia Regents University, Augusta, GA Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA
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Zhang L, Ji L, Tang X, Chen X, Li Z, Mi X, Yang L. Inhibition to DRP1 translocation can mitigate p38 MAPK-signaling pathway activation in GMC induced by hyperglycemia. Ren Fail 2015; 37:903-10. [PMID: 25857570 DOI: 10.3109/0886022x.2015.1034607] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Diabetic nephropathy (DN) is a serious complication of diabetes with a poorly defined etiology and limited treatment options. Early intervention is a key to preventing the progression of DN. Dynamin-related protein 1 (DRP1) regulates mitochondrial morphology by promoting its fission and is involved in the pathogenesis of numerous diseases. Furthermore, DRP1 is also closely associated with the development of diabetes, but its functional role in DN remains unknown. This study investigated the effect of DRP1 on early stage of DN. DRP1 expression has increased significantly in glomerular mesangial cell (GMC), which is cultivated in high glucose (HG). Ultra-microstructural changes of nephrons, expression of collagen IV and phosph-p38, ROS production, and mitochondrial function were evaluated and, at the same time, were compared with glomerular mesangial cell (GMC) cultured in normal-glucose (NG), mannitol, and a medium with mitochondrial division inhibitor 1 (Midivi-1). Endogenous DRP1 expression increased in DN. Compared to the control groups ofNG and mannitol, overexpression of DRP1 destroyed pathological changes typical of the GMC, like accumulation of extracellular matrix, and an increase in mitochondria division. In addition, Overexpression of DRP1 promoted the activation of p38, the accumulation of ROS, mitochondrial dysfunction, and the synthesis of collagen IV, and all these changes are suppressed by Midivi-1. This study demonstrates that DRP1 overexpression can accelerate pathological changes in the GMC cultured in HG. Further studies are needed to clarify the underlying mechanism of this destructive function.
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Affiliation(s)
- LieMei Zhang
- a Division of Nephrology , West China Hospital of Sichuan University , Chengdu , Sichuan , China
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20
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Primary retinal cultures as a tool for modeling diabetic retinopathy: an overview. BIOMED RESEARCH INTERNATIONAL 2015; 2015:364924. [PMID: 25688355 PMCID: PMC4320900 DOI: 10.1155/2015/364924] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/04/2014] [Accepted: 12/23/2014] [Indexed: 12/21/2022]
Abstract
Experimental models of diabetic retinopathy (DR) have had a crucial role in the comprehension of the pathophysiology of the disease and the identification of new therapeutic strategies. Most of these studies have been conducted in vivo, in animal models. However, a significant contribution has also been provided by studies on retinal cultures, especially regarding the effects of the potentially toxic components of the diabetic milieu on retinal cell homeostasis, the characterization of the mechanisms on the basis of retinal damage, and the identification of potentially protective molecules. In this review, we highlight the contribution given by primary retinal cultures to the study of DR, focusing on early neuroglial impairment. We also speculate on possible themes into which studies based on retinal cell cultures could provide deeper insight.
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Deletion of thioredoxin interacting protein (TXNIP) augments hyperoxia-induced vaso-obliteration in a mouse model of oxygen induced-retinopathy. PLoS One 2014; 9:e110388. [PMID: 25329456 PMCID: PMC4199686 DOI: 10.1371/journal.pone.0110388] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 09/12/2014] [Indexed: 02/07/2023] Open
Abstract
We have recently shown that thioredoxin interacting protein (TXNIP) is required for VEGF-mediated VEGFR2 receptor activation and angiogenic signal. Retinas from TXNIP knockout mice (TKO) exhibited higher cellular antioxidant defense compared to wild type (WT). This study aimed to examine the impact of TXNIP deletion on hyperoxia-induced vaso-obliteration in ischemic retinopathy. TKO and WT pups were subjected to oxygen-induced retinopathy model. Retinal central capillary dropout was measured at p12. Retinal redox and nitrative state were assessed by reduced-glutathione (GSH), thioredoxin reductase activity and nitrotyrosine formation. Western blot and QT-PCR were used to assess VEGF, VEGFR-2, Akt, iNOS and eNOS, thioredoxin expression, ASK-1 activation and downstream cleaved caspase-3 and PARP in retinal lysates. Retinas from TKO mice exposed to hyperoxia showed significant increases (1.5-fold) in vaso-obliteration as indicated by central capillary drop out area compared to WT. Retinas from TKO showed minimal nitrotyrosine levels (10% of WT) with no change in eNOS or iNOS mRNA expression. There was no change in levels of VEGF or activation of VEGFR2 and its downstream Akt in retinas from TKO and WT. In comparison to WT, retinas from TKO showed significantly higher level of GSH and thioredoxin reductase activity in normoxia but comparable levels under hyperoxia. Exposure of TKO to hyperoxia significantly decreased the anti-apoptotic thioredoxin protein (∼50%) level compared with WT. This effect was associated with a significant increase in activation of the apoptotic ASK-1, PARP and caspase-3 pathway. Our results showed that despite comparable VEGF level and signal in TKO, exposure to hyperoxia significantly decreased Trx expression compared to WT. This effect resulted in liberation and activation of the apoptotic ASK-1 signal. These findings suggest that TXNIP is required for endothelial cell survival and homeostasis especially under stress conditions including hyperoxia.
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Leontidis G, Al-Diri B, Hunter A. Diabetic retinopathy: current and future methods for early screening from a retinal hemodynamic and geometric approach. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.945521] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Faby H, Hillenkamp J, Roider J, Klettner A. Hyperthermia-induced upregulation of vascular endothelial growth factor in retinal pigment epithelial cells is regulated by mitogen-activated protein kinases. Graefes Arch Clin Exp Ophthalmol 2014; 252:1737-45. [PMID: 25047875 DOI: 10.1007/s00417-014-2750-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/10/2014] [Accepted: 07/11/2014] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Localized application of hyperthermia is a potential treatment for retinal diseases. Vascular endothelial growth factor (VEGF) derived from the retinal pigment epithelium (RPE) is implicated in a variety of retinal pathologies. As it has been recently shown that hyperthermia may induce VEGF in the RPE, the aim of this study was to investigate hyperthermia-induced VEGF secretion and the pathways of hyperthermal VEGF upregulation in the RPE. MATERIAL AND METHODS The human RPE cell line (Arpe-19) was exposed to 40°, 42°, 45° and 50 °C for one, five and 15 min. Cell viability was evaluated using a trypan blue exclusion assay, VEGF secretion was evaluated by an enzyme-linked immunosorbent assay ELISA) and VEGF expression was investigated using a Western blot. Involvement of mitogen-activated protein kinase (MAPK) pathways (ERK1/2, JNK, p38) and transient receptor potential vanilloid (TRPV) channels on VEGF induction was investigated using commercially available inhibitors (U0126, SB203580, SP600125, ruthenium red). Expression and phosphorylation of MAPKs was investigated using a Western blot. RESULTS Hyperthermia induces time- and temperature-dependent cell death in human RPE cells. VEGF expression and secretion is induced by hyperthermia in a time- and temperature-dependent manner mediated by p38 and to a lesser degree by JNK. TRPV channels seem to play a minor role in regulation of hyperthermia-induced VEGF secretion. CONCLUSIONS Hyperthermia induces temperature-dependent secretion of VEGF in the RPE, which is mediated by p38 and, to a lesser extent, JNK. This may lead to undesired effects from hyperthermal treatment of retinal diseases.
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Affiliation(s)
- Hendrik Faby
- Department of Ophthalmology, University Medical Center, University of Kiel, Arnold-Heller-Str. 3, 24105, Kiel, Germany
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Ergul A, Abdelsaid M, Fouda AY, Fagan SC. Cerebral neovascularization in diabetes: implications for stroke recovery and beyond. J Cereb Blood Flow Metab 2014; 34:553-63. [PMID: 24496174 PMCID: PMC3982092 DOI: 10.1038/jcbfm.2014.18] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/20/2013] [Accepted: 12/30/2013] [Indexed: 01/30/2023]
Abstract
Neovascularization is an innate physiologic response by which tissues respond to various stimuli through collateral remodeling (arteriogenesis) and new vessel formation from existing vessels (angiogenesis) or from endothelial progenitor cells (vasculogenesis). Diabetes has a major impact on the neovascularization process but the response varies between different organ systems. While excessive angiogenesis complicates diabetic retinopathy, impaired neovascularization contributes to coronary and peripheral complications of diabetes. How diabetes influences cerebral neovascularization remained unresolved until recently. Diabetes is also a major risk factor for stroke and poor recovery after stroke. In this review, we discuss the impact of diabetes, stroke, and diabetic stroke on cerebral neovascularization, explore potential mechanisms involved in diabetes-mediated neovascularization as well as the effects of the diabetic milieu on poststroke neovascularization and recovery, and finally discuss the clinical implications of these effects.
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Affiliation(s)
- Adviye Ergul
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA [3] Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia and University of Georgia College of Pharmacy, Augusta, Georgia, USA
| | - Mohammed Abdelsaid
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
| | - Abdelrahman Y Fouda
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia and University of Georgia College of Pharmacy, Augusta, Georgia, USA
| | - Susan C Fagan
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia and University of Georgia College of Pharmacy, Augusta, Georgia, USA [3] Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
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25
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Soliman S, Ishrat T, Pillai A, Somanath PR, Ergul A, El-Remessy AB, Fagan SC. Candesartan induces a prolonged proangiogenic effect and augments endothelium-mediated neuroprotection after oxygen and glucose deprivation: role of vascular endothelial growth factors A and B. J Pharmacol Exp Ther 2014; 349:444-57. [PMID: 24681872 DOI: 10.1124/jpet.113.212613] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Angiogenesis is a key component of recovery after stroke. Angiotensin II receptor blocker (ARB) treatment improves neurobehavioral outcome and is associated with enhanced angiogenesis after stroke. The purpose of this study is to investigate the temporal pattern of the ARB proangiogenic effect in the ischemic brain and its association with vascular endothelial growth factors VEGF-A and VEGF-B. Wistar rats were exposed to 90-minute middle cerebral artery occlusion and treated with candesartan (1 mg/kg) at reperfusion. The proangiogenic potential of the cerebrospinal fluid was determined at 8, 24, 48, and 72 hours using an in vitro Matrigel tube formation assay. In addition, the expression of VEGF-A and VEGF-B was measured in brain homogenates using Western blotting at the same time points. A single candesartan dose induced a prolonged proangiogenic effect and a prolonged upregulation of VEGF-A and VEGF-B in vivo. In the ischemic hemisphere, candesartan treatment was associated with stabilization of hypoxia-inducible factor-1α and preservation of angiopoietin-1. The effect of ARB treatment on endothelial cells was studied in vitro. Our results identified brain endothelial cells as one target for the action of ARBs and a source of the upregulated VEGF-A and VEGF-B, which exerted an autocrine angiogenic response, in addition to a paracrine neuroprotective effect. Taken together, this study highlights the potential usefulness of augmenting the endogenous restorative capacity of the brain through the administration of ARBs.
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Affiliation(s)
- Sahar Soliman
- Program in Clinical and Experimental Therapeutics, University of Georgia, Augusta, Georgia (S.S., T.I., P.R.S., A.E., A.B.E., S.C.F.); Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia (S.S., T.I., P.R.S., A.E., A.B.E., S.C.F.); and Departments of Psychiatry (A.P.), Medicine (P.R.S.), Physiology (A.E.), Pharmacology and Toxicology (A.B.E.), and Neurology (S.C.F.), Georgia Regents University, Augusta, Georgia
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26
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Abcouwer SF, Gardner TW. Diabetic retinopathy: loss of neuroretinal adaptation to the diabetic metabolic environment. Ann N Y Acad Sci 2014; 1311:174-90. [PMID: 24673341 DOI: 10.1111/nyas.12412] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Diabetic retinopathy (DR) impairs vision of patients with type 1 and type 2 diabetes, associated with vascular dysfunction and occlusion, retinal edema, hemorrhage, and inappropriate growth of new blood vessels. The recent success of biologic treatments targeting vascular endothelial growth factor (VEGF) demonstrates that treating the vascular aspects in the later stages of the disease can preserve vision in many patients. It would also be highly desirable to prevent the onset of the disease or arrest its progression at a stage preceding the appearance of overt microvascular pathologies. The progression of DR is not necessarily linear but may follow a series of steps that evolve over the course of multiple years. Abundant data suggest that diabetes affects the entire neurovascular unit of the retina, with an early loss of neurovascular coupling, gradual neurodegeneration, gliosis, and neuroinflammation occurring before observable vascular pathologies. In this article, we consider the pathology of DR from the point of view that diabetes causes measurable dysfunctions in the complex integral network of cell types that produce and maintain human vision.
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Affiliation(s)
- Steven F Abcouwer
- Department of Ophthalmology and Visual Sciences, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan
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Trophic factors in the pathogenesis and therapy for retinal degenerative diseases. Surv Ophthalmol 2014; 59:134-65. [PMID: 24417953 DOI: 10.1016/j.survophthal.2013.09.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 09/11/2013] [Accepted: 09/17/2013] [Indexed: 12/27/2022]
Abstract
Trophic factors are endogenously secreted proteins that act in an autocrine and/or paracrine fashion to affect vital cellular processes such as proliferation, differentiation, and regeneration, thereby maintaining overall cell homeostasis. In the eye, the major contributors of these molecules are the retinal pigment epithelial (RPE) and Müller cells. The primary paracrine targets of these secreted proteins include the photoreceptors and choriocapillaris. Retinal degenerative diseases such as age-related macular degeneration and retinitis pigmentosa are characterized by aberrant function and/or eventual death of RPE cells, photoreceptors, choriocapillaris, and other retinal cells. We discuss results of in vitro and in vivo animal studies in which candidate trophic factors, either singly or in combination, were used in an attempt to ameliorate photoreceptor and/or retinal degeneration. We also examine current trophic factor therapies as they relate to the treatment of retinal degenerative diseases in clinical studies.
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Szabadfi K, Pinter E, Reglodi D, Gabriel R. Neuropeptides, trophic factors, and other substances providing morphofunctional and metabolic protection in experimental models of diabetic retinopathy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:1-121. [PMID: 24952915 DOI: 10.1016/b978-0-12-800179-0.00001-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vision is the most important sensory modality for many species, including humans. Damage to the retina results in vision loss or even blindness. One of the most serious complications of diabetes, a disease that has seen a worldwide increase in prevalence, is diabetic retinopathy. This condition stems from consequences of pathological metabolism and develops in 75% of patients with type 1 and 50% with type 2 diabetes. The development of novel protective drugs is essential. In this review we provide a description of the disease and conclude that type 1 diabetes and type 2 diabetes lead to the same retinopathy. We evaluate existing experimental models and recent developments in finding effective compounds against this disorder. In our opinion, the best models are the long-term streptozotocin-induced diabetes and Otsuka Long-Evans Tokushima Fatty and spontaneously diabetic Torii rats, while the most promising substances are topically administered somatostatin and pigment epithelium-derived factor analogs, antivasculogenic substances, and systemic antioxidants. Future drug development should focus on these.
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Affiliation(s)
- Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary; Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary.
| | - Erika Pinter
- Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary; Department of Pharmacology and Pharmacotherapy, University of Pecs, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, PTE MTA Lendulet-PACAP Research Team, University of Pecs, Pecs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary; Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary
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Superoxide dismutase1 levels in North Indian population with age-related macular degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:365046. [PMID: 24363822 PMCID: PMC3864086 DOI: 10.1155/2013/365046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 10/20/2013] [Accepted: 10/28/2013] [Indexed: 12/21/2022]
Abstract
Aim. The aim of the study was to estimate the levels of superoxide dismutase1 (SOD1) in patients of age-related macular degeneration (AMD) and examine the role of oxidative stress, smoking, hypertension, and other factors involved in the pathogenesis of AMD. Methods. 115 AMD patients and 61 healthy controls were recruited for this study. Serum SOD1 levels were determined by ELISA and were correlated to various risk factors. Logistic regression model of authenticity, by considering SOD1 as independent variable, has been developed along with ROC curve. Results. The SOD1 levels were significantly higher in AMD patients as compared to those of the controls. The difference was not significant for wet and dry AMD. However, the difference was significant between wet AMD subtypes. Nonsignificance of the Hosmer-Lemeshow goodness of fit statistic (χ2 = 10.516, df = 8, P = 0.231) indicates the appropriateness of logistic regression model to predict AMD. Conclusion. Oxidative stress in AMD patients may mount compensatory response resulting in increased levels of SOD1 in AMD patients. To predict the risk of AMD on the basis of SOD1, a logistic regression model shows authenticity of 78%, and area under the ROC curve (0.827, P = .0001) with less standard error of 0.033 coupled with 95% confidence interval of 0.762–0.891 further validates the model.
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Phytoestrogen α-Zearalanol attenuates homocysteine-induced apoptosis in human umbilical vein endothelial cells. BIOMED RESEARCH INTERNATIONAL 2013; 2013:813450. [PMID: 24195080 PMCID: PMC3806352 DOI: 10.1155/2013/813450] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 08/28/2013] [Indexed: 01/21/2023]
Abstract
Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases. The enhanced nitrative stress plays an important role in homocysteine-induced endothelial dysfunction. Previous studies have showed that phytoestrogen α -zearalanol alleviated endothelial injury in ovariectomized hyperhomocysteinemic rats; however, the underlying mechanism remains to be clarified. This study was to investigate the effects of α -zearalanol on homocysteine-induced endothelial apoptosis in vitro and explore the possible role of nitrative stress in these effects. Results showed that homocysteine (500 μ mol/L, 24 h) induced the apoptosis of human umbilical vein endothelial cells (HUVECs) obviously, and this effect was significantly attenuated by pretreatment with α -zearalanol (10(-8)~10(-6) mol/L). Moreover, α -zearalanol downregulated proapoptotic protein Bax, upregulated antiapoptotic proteins Bcl-2 and Bcl-XL, and decreased the expression and activity of caspase-9. These findings demonstrated that α -zearalanol could effectively alleviate homocysteine-induced endothelial apoptosis, and this antiapoptosis effect might be related to the inhibition of the intrinsic pathway. Western blot indicated an enhanced 3-nitrotyrosine expression in HUVECs when challenged with homocysteine, which was attenuated by pretreatment with α -zearalanol. This result implied that inhibition of nitrative stress might play a role in the protective effect of α -zearalanol on endothelial cells. Such discovery may shed a novel light on the antiatherogenic activities of α -zearalanol in hyperhomocysteinemia.
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Ying WZ, Aaron KJ, Sanders PW. Transforming growth factor-β regulates endothelial function during high salt intake in rats. Hypertension 2013; 62:951-6. [PMID: 24041947 DOI: 10.1161/hypertensionaha.113.01835] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies have demonstrated that an increase in dietary NaCl (salt) intake stimulated endothelial cells to produce transforming growth factor-β (TGF-β). The intent of the present study was to determine the functional significance of increased TGF-β on endothelial cell function. Young Sprague-Dawley rats were fed diets containing 0.3 or 8.0% NaCl for 2 days before treatment with a specific inhibitor of the TGF-β receptor I/activin receptor-like kinase 5 kinase, or vehicle for another 2 days. At day 4 of study, endothelial phosphorylated Smad2 (S465/467) increased and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) levels decreased in the high-salt-treated rats. In addition, phosphorylated Akt (S473) and phosphorylation of the endothelial isoform of NO synthase (NOS3) at S1177 increased. Treatment with the TGF-β receptor I/activin receptor-like kinase 5 inhibitor reduced Smad2 phosphorylation to levels observed in rats on the low-salt diet and prevented the downstream signaling events induced by the high-salt diet. In human umbilical vein endothelial cells, reduction in PTEN levels increased phosphorylated Akt and NOS3. Treatment of macrovascular endothelial cells with TGF-β1 increased phosphorylated NOS3 and the concentration of NO metabolites in the medium but had no effect on either of these variables in cells pretreated with small interfering RNA directed against PTEN. Thus, during high salt intake, an increase in TGF-β directly promoted a reduction in endothelial PTEN levels, which in turn regulated Akt activation and NOS3 phosphorylation. This effect closes a feedback loop that potentially mitigates the effect of TGF-β on the vasculature.
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Affiliation(s)
- Wei-Zhong Ying
- Division of Nephrology/Department of Medicine, 642 Lyons-Harrison Research Bldg, 1530 Third Ave, South, University of Alabama at Birmingham, Birmingham, AL 35294-0007.
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Cachafeiro M, Bemelmans AP, Samardzija M, Afanasieva T, Pournaras JA, Grimm C, Kostic C, Philippe S, Wenzel A, Arsenijevic Y. Hyperactivation of retina by light in mice leads to photoreceptor cell death mediated by VEGF and retinal pigment epithelium permeability. Cell Death Dis 2013; 4:e781. [PMID: 23990021 PMCID: PMC3763463 DOI: 10.1038/cddis.2013.303] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/22/2013] [Accepted: 06/17/2013] [Indexed: 11/29/2022]
Abstract
Light toxicity is suspected to enhance certain retinal degenerative processes such as age-related macular degeneration. Death of photoreceptors can be induced by their exposure to the visible light, and although cellular processes within photoreceptors have been characterized extensively, the role of the retinal pigment epithelium (RPE) in this model is less well understood. We demonstrate that exposition to intense light causes the immediate breakdown of the outer blood–retinal barrier (BRB). In a molecular level, we observed the slackening of adherens junctions tying up the RPE and massive leakage of albumin into the neural retina. Retinal pigment epithelial cells normally secrete vascular endothelial growth factor (VEGF) at their basolateral side; light damage in contrast leads to VEGF increase on the apical side – that is, in the neuroretina. Blocking VEGF, by means of lentiviral gene transfer to express an anti-VEGF antibody in RPE cells, inhibits outer BRB breakdown and retinal degeneration, as illustrated by functional, behavioral and morphometric analysis. Our data show that exposure to high levels of visible light induces hyperpermeability of the RPE, likely involving VEGF signaling. The resulting retinal edema contributes to irreversible damage to photoreceptors. These data suggest that anti-VEGF compounds are of therapeutic interest when the outer BRB is altered by retinal stresses.
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Affiliation(s)
- M Cachafeiro
- Unit of Gene Therapy & Stem Cell Biology, Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
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Abstract
The biochemical perturbations in diabetes mellitus (DM) create the conditions for the production of free radicals, the consequence of which is increased oxidative stress. Evidence has accrued over the past 2 decades that suggests that oxidative stress is an important pathogenetic factor in the development of diabetic retinopathy (DR). Experimental data show that the use of strategies that ameliorate oxidative stress can prevent and retard the development of DR in the animal model. Clinical observations also suggest that reducing oxidative stress may help to reverse pathological manifestations of DR. The present article constitutes an examination of the role of antioxidants in the management of DR and the current state of clinically relevant knowledge.
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Affiliation(s)
- Michael Williams
- Medical Ophthalmology, Department of Ophthalmology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, BT12 6BA, Northern Ireland, UK
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Astaxanthin attenuates the apoptosis of retinal ganglion cells in db/db mice by inhibition of oxidative stress. Mar Drugs 2013; 11:960-74. [PMID: 23519150 PMCID: PMC3705382 DOI: 10.3390/md11030960] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 02/17/2013] [Accepted: 03/01/2013] [Indexed: 12/11/2022] Open
Abstract
Diabetic retinopathy is a common diabetic eye disease caused by changes in retinal ganglion cells (RGCs). It is an ocular manifestation of systemic disease, which affects up to 80% of all patients who have had diabetes for 10 years or more. The genetically diabetic db/db mouse, as a model of type-2 diabetes, shows diabetic retinopathy induced by apoptosis of RGCs. Astaxanthin is a carotenoid with powerful antioxidant properties that exists naturally in various plants, algae and seafood. Here, astaxanthin was shown to reduce the apoptosis of RGCs and improve the levels of oxidative stress markers, including superoxide anion, malondialdehyde (MDA, a marker of lipid peroxidation), 8-hydroxy-2-deoxyguanosine (8-OHdG, indicator of oxidative DNA damage) and MnSOD (manganese superoxide dismutase) activity in the retinal tissue of db/db mouse. In addition, astaxanthin attenuated hydrogen peroxide(H2O2)-induced apoptosis in the transformed rat retinal ganglion cell line RGC-5. Therefore, astaxanthin may be developed as an antioxidant drug to treat diabetic retinopathy.
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Delayed preconditioning prevents ischemia/reperfusion-induced endothelial injury in rats: role of ROS and eNOS. J Transl Med 2013; 93:168-80. [PMID: 23147223 DOI: 10.1038/labinvest.2012.160] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Ischemic preconditioning (IPC) strongly protects against ischemia/reperfusion (I/R) injury; however, the molecular mechanism involved in delayed preconditioning-induced endothelial protection in peripheral arteries is unknown. Therefore, we examined using functional, morphologic and molecular biologic studies whether delayed IPC decreases formation of reactive oxygen species and upregulates endothelial nitric oxide synthase (eNOS) that in turn contributes to vascular endothelial protection. Adult male Sprague-Dawley rats were subjected to 30-min ischemia induced by mesenteric artery occlusion followed by 60-min reperfusion 24 h after sham surgery or preconditioning (three cycles of 5-min ischemia/5-min reperfusion). Delayed preconditioning prevented the I/R-induced impairment of endothelium-dependent relaxations to acetylcholine (maximal relaxation: sham 91.4±2.2%; I/R 54.0±4.0%; IPC 80.2±6.3%). This protective effect was abolished by NOS inhibitor N(G)-nitro-L-arginine methyl ester and not changed by ascorbic acid. Electron microscopy showed marked endothelial damage after I/R and the ultrastructural changes were prevented by delayed preconditioning. Following I/R, the impairment of eNOS phosphorylation and expression was observed in mesenteric vessels. Furthermore, phosphatidylinositol 3-kinase (PI3K) and Akt phosphorylation were reduced, although total PI3K and Akt remained unchanged. IPC restored I/R-induced impairment of eNOS expression and activity. This was possibly the result of the recovery of PI3K/Akt phosphorylation. Furthermore, I/R increased serum level of malondialdehyde, intravascular superoxide and nitrotyrosine generation, which were abrogated by IPC. These results suggest that delayed preconditioning prevented I/R-induced endothelial injury in peripheral resistance vasculature, both in terms of functional and structural changes. Endothelial protection afforded by delayed IPC is associated with inhibition of oxidative stress and upregulation of PI3K/Akt/eNOS pathway.
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Babbar L, Mahadevan N, Balakumar P. Fenofibrate attenuates impaired ischemic preconditioning-mediated cardioprotection in the fructose-fed hypertriglyceridemic rat heart. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:319-29. [DOI: 10.1007/s00210-012-0830-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 12/20/2012] [Indexed: 02/07/2023]
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Tarr JM, Kaul K, Chopra M, Kohner EM, Chibber R. Pathophysiology of diabetic retinopathy. ISRN OPHTHALMOLOGY 2013; 2013:343560. [PMID: 24563789 PMCID: PMC3914226 DOI: 10.1155/2013/343560] [Citation(s) in RCA: 265] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 12/13/2012] [Indexed: 12/13/2022]
Abstract
Diabetes is now regarded as an epidemic, with the population of patients expected to rise to 380 million by 2025. Tragically, this will lead to approximately 4 million people around the world losing their sight from diabetic retinopathy, the leading cause of blindness in patients aged 20 to 74 years. The risk of development and progression of diabetic retinopathy is closely associated with the type and duration of diabetes, blood glucose, blood pressure, and possibly lipids. Although landmark cross-sectional studies have confirmed the strong relationship between chronic hyperglycaemia and the development and progression of diabetic retinopathy, the underlying mechanism of how hyperglycaemia causes retinal microvascular damage remains unclear. Continued research worldwide has focussed on understanding the pathogenic mechanisms with the ultimate goal to prevent DR. The aim of this paper is to introduce the multiple interconnecting biochemical pathways that have been proposed and tested as key contributors in the development of DR, namely, increased polyol pathway, activation of protein kinase C (PKC), increased expression of growth factors such as vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1), haemodynamic changes, accelerated formation of advanced glycation endproducts (AGEs), oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and subclinical inflammation and capillary occlusion. New pharmacological therapies based on some of these underlying pathogenic mechanisms are also discussed.
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Affiliation(s)
| | | | | | | | - Rakesh Chibber
- Institute of Biomedical and Clinical Science, Peninsula College of Medicine and Dentistry, University of Exeter, St Luke's Campus, Magdalen Road, Exeter EX1 2LU, UK
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Tu M, Huang Y, Li HL, Gao ZH. The stress caused by nitrite with titanium dioxide nanoparticles under UVA irradiation in human keratinocyte cell. Toxicology 2012; 299:60-8. [DOI: 10.1016/j.tox.2012.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/27/2022]
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Abdelsaid MA, El-Remessy AB. S-glutathionylation of LMW-PTP regulates VEGF-mediated FAK activation and endothelial cell migration. J Cell Sci 2012; 125:4751-60. [PMID: 22854047 DOI: 10.1242/jcs.103481] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although promising, the ability to regulate angiogenesis through delivery of VEGF remains an unrealized goal. We have shown previously that physiological levels of peroxynitrite (1 µM) are required for a VEGF-mediated angiogenic response, yet the redox-regulated mechanisms that govern the VEGF signal remain unexplored. We assessed the impact of VEGF and peroxynitrite on modifying redox-state, the level of reduced-glutathione (GSH) and S-glutathionylation on regulation of the low molecular weight protein tyrosine phosphatase (LMW-PTP) and focal adhesion kinase (FAK), which are key mediators of VEGF-mediated cell migration. Stimulation of human microvascular endothelial (HME) cells with VEGF (20 ng/ml) or peroxynitrite (1 µM) caused an immediate and reversible negative-shift in the cellular redox-state and thiol oxidation of LMW-PTP, which culminated in cell migration. VEGF causes reversible S-glutathionylation of LMW-PTP, which inhibits its phosphorylation and activity, and causes the transient activation of FAK. Modulating the redox-state using decomposing peroxynitrite (FeTPPS, 2.5 µM) or the GSH-precursor [N-acetylcysteine (NAC), 1 mM] caused a positive-shift of the redox-state and prevented VEGF-mediated S-glutathionylation and oxidative inhibition of LMW-PTP. NAC and FeTPPS prevented the activation of FAK, its association with LMW-PTP and cell migration. Inhibiting LMW-PTP expression markedly enhanced FAK activation and cell migration. Although mild oxidative stress achieved by combining VEGF with 0.1-0.2 mM peroxynitrite augmented cell migration, an acute shift to oxidative stress achieved by combining VEGF with 0.5 mM peroxynitrite induced and sustained FAK activation, and LMW-PTP S-glutathionylation, resulting in LMW-PTP inactivation and inhibited cell migration. In conclusion, our findings demonstrate that a balanced redox-state is required for VEGF to facilitate reversible S-glutathionylation of LMW-PTP, FAK activation and endothelial cell migration. Shifting the redox-state to reductive stress or oxidative stress inhibited the VEGF-mediated angiogenic response.
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El-Azab MF, Hazem RM, Moustafa YM. Role of simvastatin and/or antioxidant vitamins in therapeutic angiogenesis in experimental diabetic hindlimb ischemia: effects on capillary density, angiogenesis markers, and oxidative stress. Eur J Pharmacol 2012; 690:31-41. [PMID: 22705060 DOI: 10.1016/j.ejphar.2012.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 06/05/2012] [Indexed: 02/09/2023]
Abstract
Therapeutic angiogenesis has emerged as an attractive approach for the management of peripheral arterial disease in diabetic patients. Oxidative stress generated and aggravated by prolonged hyperglycemia may interfere with and destroy the newly formed blood vessels. Angiogenic effect of simvastatin has been reported; however, its exact mechanism is yet to be evaluated. In addition, the exact role of antioxidant vitamins in diabetic peripheral arterial disease is still controversial. The present study was undertaken to investigate the therapeutic potential of simvastatin and antioxidant vitamins (E and C) and their combined effects on angiogenesis in diabetic hind-limb ischemia. Streptozotocin diabetic rats were treated for 6 weeks with simvastatin either alone or in combination with vitamin E or vitamin C. Parameters of angiogenesis, nitric oxide, heme oxygenase-1 (HO-1), and oxidative stress markers were evaluated. CD31 immunostaining revealed an increased capillary density in ischemic gastrocnemious tissue of diabetic rats treated with either simvastatin or its combination with vitamin C. This effect was accompanied by up-regulated plasma levels of HO-1, nitric oxide, vascular endothelial growth factor (VEGF) and its intra-muscular receptor type-2 (Flk-1). Tissue reduced glutathione and antioxidant enzymes activities were normalized in groups treated with antioxidant vitamins or their combination with simvastatin with concomitant blunting of lipid peroxidation. Vitamins E and C, through their antioxidant effects, evidently enhanced the angiogenic effect of simvastatin in ischemic diabetic muscle. Hence, the use of antioxidant vitamins combined with statins to induce therapeutic angiogenesis is a promising strategy in the management of diabetes-associated peripheral arterial disease.
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Affiliation(s)
- Mona F El-Azab
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt.
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Prakash R, Somanath PR, El-Remessy AB, Kelly-Cobbs A, Stern JE, Dore-Duffy P, Johnson M, Fagan SC, Ergul A. Enhanced cerebral but not peripheral angiogenesis in the Goto-Kakizaki model of type 2 diabetes involves VEGF and peroxynitrite signaling. Diabetes 2012; 61:1533-42. [PMID: 22403298 PMCID: PMC3357273 DOI: 10.2337/db11-1528] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We previously reported enhanced cerebrovascular remodeling and arteriogenesis in experimental type 2 diabetes. This study tested the hypotheses that 1) cerebral but not peripheral angiogenesis is increased in a spatial manner and 2) peroxynitrite orchestrates vascular endothelial growth factor (VEGF)-mediated brain angiogenesis in diabetes. Stereology of brain, eye, and skeletal muscle microvasculature was evaluated in control and diabetic rats using three-dimensional images. Migration and tube formation properties of brain microvascular endothelial cells (BMECs) were analyzed as markers of angiogenesis. Vascular density, volume, and surface area were progressively increased from rostral to caudal sections in both the cerebral cortex and striatum in diabetic rats. Unperfused new vessels were more prominent and the pericyte-to-endothelial cell ratio was decreased in diabetes. Vascularization was greater in the retina but lower in the peripheral circulation. VEGF and nitrotyrosine levels were higher in cerebral microvessels of diabetic animals. Migratory and tube formation properties were enhanced in BMECs from diabetic rats, which also expressed high levels of basal VEGF, nitrotyrosine, and membrane-type (MT1) matrix metalloprotease (MMP). VEGF-neutralizing antibody and inhibitors of peroxynitrite, src kinase, or MMP blocked the migration. Diabetes increases and spatially regulates cerebral neovascularization. Increased VEGF-dependent angiogenic function in BMECs is mediated by peroxynitrite and involves c-src and MT1-MMP activation.
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Affiliation(s)
- Roshini Prakash
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, Athens, Georgia
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Athens, Georgia
| | - Payaningal R. Somanath
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, Athens, Georgia
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Athens, Georgia
| | - Azza B. El-Remessy
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, Athens, Georgia
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Athens, Georgia
| | - Aisha Kelly-Cobbs
- Department of Physiology, Georgia Health Sciences University, Augusta, Georgia
| | - Javier E. Stern
- Department of Physiology, Georgia Health Sciences University, Augusta, Georgia
| | - Paula Dore-Duffy
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan
| | - Maribeth Johnson
- Department of Biostatistics, Georgia Health Sciences University, Augusta, Georgia
| | - Susan C. Fagan
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, Athens, Georgia
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Athens, Georgia
| | - Adviye Ergul
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, Athens, Georgia
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Athens, Georgia
- Department of Physiology, Georgia Health Sciences University, Augusta, Georgia
- Corresponding author: Adviye Ergul,
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Blockade of VEGF-induced GSK/β-catenin signaling, uPAR expression and increased permeability by dominant negative p38α. Exp Eye Res 2012; 100:101-8. [PMID: 22564969 DOI: 10.1016/j.exer.2012.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 02/11/2012] [Accepted: 03/21/2012] [Indexed: 11/23/2022]
Abstract
The goal of this study was to define the role of p38alpha MAP kinase in VEGF-induced vascular permeability increase. Activation of p38 is correlated with increased permeability in endothelial cells treated with VEGF or high glucose and in retinas of diabetic animal models. We have shown previously that p38 inhibitors preserve endothelial barrier function and block VEGF-induced GSK/beta-catenin signaling. Here, we present data demonstrating that adenoviral vector delivery of a dominant negative p38alpha mutant blocks this signaling pathway and preserves barrier function. This p38alpha mutant was altered on its ATP-binding site, which eliminates its kinase activity. Bovine retinal endothelial (BRE) cells were transduced with recombinant adenovirus containing the p38alpha mutants or empty vector. Successful transduction was confirmed by expression of GFP and p38 increase. Blockade of p38 activity by p38alpha mutant was demonstrated by inhibition of VEGF-induced phosphorylation of a p38 target, MAP kinase activated protein kinase 2 (MK-2). The mutant also prevented VEGF-induced GSK phosphorylation and beta-catenin cytosolic accumulation and nuclear translocation as shown by cell fractionation and Western blotting. Quantitative real-time PCR demonstrated that this mutant inhibited VEGF-induced uPAR gene expression. Importantly, this same mutant also strongly abrogated VEGF-induced endothelial barrier breakdown as determined by measuring transcellular electrical resistance and tracer flux through endothelial cell monolayer. This study indicates a critical role of p38alpha in VEGF-induced permeability and offers a new strategy for developing potent and specific therapies for treatment of retinal diseases associated with vascular barrier dysfunction.
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Tang WX, Wu WH, Zeng XX, Bo H, Huang SM. Early protective effect of mitofusion 2 overexpression in STZ-induced diabetic rat kidney. Endocrine 2012; 41:236-47. [PMID: 22095488 DOI: 10.1007/s12020-011-9555-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 10/27/2011] [Indexed: 02/05/2023]
Abstract
Diabetic nephropathy (DN) is a serious complication of diabetes with a poorly defined etiology and limited treatment options. Early intervention is key to preventing the progression of DN. Mitofusin 2 (Mfn2) regulates mitochondrial morphology and signaling, and is involved in the pathogenesis of numerous diseases. Furthermore, Mfn2 is also closely associated with the development of diabetes, but its functional roles in the diabetic kidney remain unknown. This study investigated the effect of Mfn2 at an early stage of DN. Mfn2 was overexpressed by adenovirus-mediated gene transfer in streptozotocin-induced diabetic rats. Clinical parameters (proteinuria, albumin/creatinine ratio), pathological changes, ultra-microstructural changes in nephrons, expression of collagen IV and phosph-p38, ROS production, mitochondrial function, and apoptosis were evaluated and compared with diabetic rats expressing control levels of Mfn2. Endogenous Mfn2 expression decreased with time in DN. Compared to the blank transfection control group, overexpression of Mfn2 decreased kidney weight relative to body weight, reduced proteinuria and ACR, and improved pathological changes typical of the diabetic kidney, like enlargement of glomeruli, accumulation of ECM, and thickening of the basement membrane. In addition, Mfn2 overexpression inhibited activation of p38, and the accumulation of ROS; prevented mitochondrial dysfunction; and reduced the synthesis of collagen IV, but did not affect apoptosis of kidney cells. This study demonstrates that Mfn2 overexpression can attenuate pathological changes in the kidneys of diabetic rats. Further studies are needed to clarify the underlying mechanism of this protective function. Mfn2 might be a potential therapeutic target for the treatment of early stage DN.
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Affiliation(s)
- Wan Xin Tang
- Division of Nephrology, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
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Podowski M, Calvi C, Metzger S, Misono K, Poonyagariyagorn H, Lopez-Mercado A, Ku T, Lauer T, McGrath-Morrow S, Berger A, Cheadle C, Tuder R, Dietz HC, Mitzner W, Wise R, Neptune E. Angiotensin receptor blockade attenuates cigarette smoke-induced lung injury and rescues lung architecture in mice. J Clin Invest 2011; 122:229-40. [PMID: 22182843 DOI: 10.1172/jci46215] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 11/09/2011] [Indexed: 01/24/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no disease-altering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β-specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β-targeted therapies for patients with COPD.
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Affiliation(s)
- Megan Podowski
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Hüttemann M, Lee I, Malek MH. (-)-Epicatechin maintains endurance training adaptation in mice after 14 days of detraining. FASEB J 2011; 26:1413-22. [PMID: 22179525 DOI: 10.1096/fj.11-196154] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to determine whether (-)-epicatechin (mainly found in cocoa) could attenuate detraining effects in the hindlimb muscles of mice. Thirty-two male mice were randomized into 4 groups: control, trained, trained with 14 d of detraining and vehicle (DT-14-W), and trained with 14 d of detraining and (-)-epicatechin [DT-14-(-)-Epi]. DT-14-(-)-Epi received (-)-epicatechin (1.0 mg/kg 2 ×/d), whereas water was given to the DT-14-W group. The latter 3 groups performed 5 wk of endurance training 5 ×/wk. Hindlimb muscles were harvested, and Western blots, as well as enzyme analyses, were performed. Training significantly increased capillary-to-fiber ratio (≈ 78.8%), cytochrome-c oxidase (≈ 35%), and activity (≈ 144%) compared to controls. These adaptations returned to control levels for the DT-14-W group, whereas the DT-14-(-)-Epi group was able to maintain capillary-to-fiber ratio (≈ 44%), CcO protein expression (≈ 45%), and activity (≈ 108%) above control levels. In addition, the increase in capillarity was related to decreased protein expression of thrombospondin-1, an antiangiogenic regulator. Furthermore, there were no significant differences in endurance capacity between the trained and DT-14-(-)-Epi groups. Our data suggest that (-)-epicatechin may be a suitable compound to maintain exercise-induced improved capillarity and mitochondrial capacity, even when exercise regimens are discontinued.
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Affiliation(s)
- Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Insulin-Mediated Inhibition of p38 Mitogen-Activated Protein Kinase Protects Cardiomyocytes in Severe Burns. J Burn Care Res 2011; 32:591-9. [DOI: 10.1097/bcr.0b013e31822dc3f2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Frey T, Antonetti DA. Alterations to the blood-retinal barrier in diabetes: cytokines and reactive oxygen species. Antioxid Redox Signal 2011; 15:1271-84. [PMID: 21294655 DOI: 10.1089/ars.2011.3906] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness in Western society. Since the prevalence of diabetes continues to increase dramatically, the impact of DR will only worsen unless new therapeutic options are developed. Recent data demonstrate that oxidative stress contributes to the pathology of DR and inhibition of oxidative stress reduces retinal vascular permeability. However, direct mechanisms by which oxidative stress alters the blood-retinal barrier (BRB) and increases vascular permeability remain to be elucidated. A large body of evidence demonstrates a clear role for altered expression of cytokines and growth factors in DR, resulting in increased vascular permeability, and the molecular mechanisms for these processes are beginning to emerge. The pathology of DR is likely a result of metabolic dysregulation contributing to both oxidative stress and cytokine production. This review will examine the evidence for oxidative stress, growth factors, and other cytokines in tight junction regulation and vascular permeability in DR.
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Affiliation(s)
- Tiffany Frey
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
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Tang J, Kern TS. Inflammation in diabetic retinopathy. Prog Retin Eye Res 2011; 30:343-58. [PMID: 21635964 PMCID: PMC3433044 DOI: 10.1016/j.preteyeres.2011.05.002] [Citation(s) in RCA: 794] [Impact Index Per Article: 61.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 05/14/2011] [Accepted: 05/16/2011] [Indexed: 12/14/2022]
Abstract
Diabetes causes a number of metabolic and physiologic abnormalities in the retina, but which of these abnormalities contribute to recognized features of diabetic retinopathy (DR) is less clear. Many of the molecular and physiologic abnormalities that have been found to develop in the retina in diabetes are consistent with inflammation. Moreover, a number of anti-inflammatory therapies have been found to significantly inhibit development of different aspects of DR in animal models. Herein, we review the inflammatory mediators and their relationship to early and late DR, and discuss the potential of anti-inflammatory approaches to inhibit development of different stages of the retinopathy. We focus primarily on information derived from in vivo studies, supplementing with information from in vitro studies were important.
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Affiliation(s)
- Johnny Tang
- Department of Ophthalmology and Visual Sciences, University Hospitals Eye Institute, Case Western Reserve University, Cleveland, OH, USA
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Deb I, Das S. Thyroid hormones protect astrocytes from morphine-induced apoptosis by regulating nitric oxide and pERK 1/2 pathways. Neurochem Int 2011; 58:861-71. [DOI: 10.1016/j.neuint.2011.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 12/16/2010] [Accepted: 01/03/2011] [Indexed: 12/22/2022]
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El-Remessy AB, Rajesh M, Mukhopadhyay P, Horváth B, Patel V, Al-Gayyar MMH, Pillai BA, Pacher P. Cannabinoid 1 receptor activation contributes to vascular inflammation and cell death in a mouse model of diabetic retinopathy and a human retinal cell line. Diabetologia 2011; 54:1567-78. [PMID: 21373835 PMCID: PMC3375271 DOI: 10.1007/s00125-011-2061-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 12/30/2010] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS Recent studies have demonstrated that cannabinoid-1 (CB(1)) receptor blockade ameliorated inflammation, endothelial and/or cardiac dysfunction, and cell death in models of nephropathy, atherosclerosis and cardiomyopathy. However the role of CB(1) receptor signalling in diabetic retinopathy remains unexplored. Using genetic deletion or pharmacological inhibition of the CB(1) receptor with SR141716 (rimonabant) in a rodent model of diabetic retinopathy or in human primary retinal endothelial cells (HREC) exposed to high glucose, we explored the role of CB(1) receptors in the pathogenesis of diabetic retinopathy. METHODS Diabetes was induced using streptozotocin in C57BL/6J Cb(1) (also known as Cnr1)(+/+) and Cb(1)(-/-) mice aged 8 to 12 weeks. Samples from mice retina or HREC were used to determine: (1) apoptosis; (2) activity of nuclear factor kappa B, intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), poly (ADP-ribose) polymerase and caspase-3; (3) content of 3-nitrotyrosine and reactive oxygen species; and (4) activation of p38/Jun N-terminal kinase/mitogen-activated protein kinase (MAPK). RESULTS Deletion of CB(1) receptor or treatment of diabetic mice with CB(1) receptor antagonist SR141716 prevented retinal cell death. Treatment of diabetic mice or HREC cells exposed to high glucose with SR141716 attenuated the oxidative and nitrative stress, and reduced levels of nuclear factor κB, ICAM-1 and VCAM-1. In addition, SR141716 attenuated the diabetes- or high glucose-induced pro-apoptotic activation of MAPK and retinal vascular cell death. CONCLUSIONS/INTERPRETATION Activation of CB(1) receptors may play an important role in the pathogenesis of diabetic retinopathy by facilitating MAPK activation, oxidative stress and inflammatory signalling. Conversely, CB(1) receptor inhibition may be beneficial in the treatment of this devastating complication of diabetes.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Apoptosis/physiology
- Caspase 3/metabolism
- Cell Line
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/physiopathology
- Diabetic Retinopathy/etiology
- Diabetic Retinopathy/metabolism
- Diabetic Retinopathy/physiopathology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Glucose/pharmacology
- Humans
- Intercellular Adhesion Molecule-1/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NF-kappa B/metabolism
- Oxidative Stress/drug effects
- Reactive Oxygen Species/metabolism
- Receptor, Cannabinoid, CB1/deficiency
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/physiology
- Retina/metabolism
- Retina/pathology
- Retina/physiopathology
- Retinal Vasculitis/metabolism
- Retinal Vasculitis/physiopathology
- Signal Transduction/physiology
- Streptozocin/adverse effects
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Affiliation(s)
- A. B. El-Remessy
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA. Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - M. Rajesh
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiological Studies, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane, MSC-9413, Bethesda, MD 20892-9413, USA
| | - P. Mukhopadhyay
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiological Studies, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane, MSC-9413, Bethesda, MD 20892-9413, USA
| | - B. Horváth
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiological Studies, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane, MSC-9413, Bethesda, MD 20892-9413, USA. Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary
| | - V. Patel
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiological Studies, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane, MSC-9413, Bethesda, MD 20892-9413, USA
| | - M. M. H. Al-Gayyar
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA. Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - B. A. Pillai
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA. Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - P. Pacher
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiological Studies, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane, MSC-9413, Bethesda, MD 20892-9413, USA
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