Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction

Objective: Retinal ischemic disease is a major cause of vision loss. Current treatment options are limited to late-stage diseases, and the molecular mechanisms of the initial insult are not fully understood. We have previously shown that the deletion of the mitochondrial arginase isoform, arginase 2...

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Main Authors: Esraa Shosha, Abdelrahman Y. Fouda, Tahira Lemtalsi, Stephen Haigh, David Fulton, Ahmed Ibrahim, Mohamed Al-Shabrawey, R. William Caldwell, Ruth B. Caldwell
Format: Article
Language:English
Published: Elsevier 2021-11-01
Series:Molecular Metabolism
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2212877821001186
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author Esraa Shosha
Abdelrahman Y. Fouda
Tahira Lemtalsi
Stephen Haigh
David Fulton
Ahmed Ibrahim
Mohamed Al-Shabrawey
R. William Caldwell
Ruth B. Caldwell
author_facet Esraa Shosha
Abdelrahman Y. Fouda
Tahira Lemtalsi
Stephen Haigh
David Fulton
Ahmed Ibrahim
Mohamed Al-Shabrawey
R. William Caldwell
Ruth B. Caldwell
author_sort Esraa Shosha
collection DOAJ
description Objective: Retinal ischemic disease is a major cause of vision loss. Current treatment options are limited to late-stage diseases, and the molecular mechanisms of the initial insult are not fully understood. We have previously shown that the deletion of the mitochondrial arginase isoform, arginase 2 (A2), limits neurovascular injury in models of ischemic retinopathy. Here, we investigated the involvement of A2-mediated alterations in mitochondrial dynamics and function in the pathology. Methods: We used wild-type (WT), global A2 knockout (A2KO-) mice, cell-specific A2 knockout mice subjected to retinal ischemia/reperfusion (I/R), and bovine retinal endothelial cells (BRECs) subjected to an oxygen-glucose deprivation/reperfusion (OGD/R) insult. We used western blotting to measure levels of cell stress and death markers and the mitochondrial fragmentation protein, dynamin related protein 1 (Drp1). We also used live cell mitochondrial labeling and Seahorse XF analysis to evaluate mitochondrial fragmentation and function, respectively. Results: We found that the global deletion of A2 limited the I/R-induced disruption of retinal layers, fundus abnormalities, and albumin extravasation. The specific deletion of A2 in endothelial cells was protective against I/R-induced neurodegeneration. The OGD/R insult in BRECs increased A2 expression and induced cell stress and cell death, along with decreased mitochondrial respiration, increased Drp1 expression, and mitochondrial fragmentation. The overexpression of A2 in BREC also decreased mitochondrial respiration, promoted increases in the expression of Drp1, mitochondrial fragmentation, and cell stress and resulted in decreased cell survival. In contrast, the overexpression of the cytosolic isoform, arginase 1 (A1), did not affect these parameters. Conclusions: This study is the first to show that A2 in endothelial cells mediates retinal ischemic injury through a mechanism involving alterations in mitochondrial dynamics and function.
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spelling doaj.art-72187996925f42ffb82d739c8a5f3c642022-12-21T21:24:36ZengElsevierMolecular Metabolism2212-87782021-11-0153101273Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunctionEsraa Shosha0Abdelrahman Y. Fouda1Tahira Lemtalsi2Stephen Haigh3David Fulton4Ahmed Ibrahim5Mohamed Al-Shabrawey6R. William Caldwell7Ruth B. Caldwell8Vascular Biology Center, Augusta University, Augusta, GA, USA; Department of Clinical Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt; Vision Discovery Institute, Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USAVascular Biology Center, Augusta University, Augusta, GA, USA; Department of Clinical Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt; Vision Discovery Institute, Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USAVascular Biology Center, Augusta University, Augusta, GA, USA; Vision Discovery Institute, Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USAVascular Biology Center, Augusta University, Augusta, GA, USAVascular Biology Center, Augusta University, Augusta, GA, USAVision Discovery Institute, Augusta University, Augusta, GA, USA; Wayne State University, Department of Ophthalmology, Visual, and Anatomical Sciences, Department of Pharmacology, Detroit, MI, USA; Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, EgyptVision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Oral Biology, Dental College of Georgia, Augusta, GA, USAVision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USAVascular Biology Center, Augusta University, Augusta, GA, USA; Vision Discovery Institute, Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA; Corresponding author. Medical College of Georgia, Augusta University, 1460 Laney Walker Blvd, CB 3209A, Augusta, GA 30912, USA.Objective: Retinal ischemic disease is a major cause of vision loss. Current treatment options are limited to late-stage diseases, and the molecular mechanisms of the initial insult are not fully understood. We have previously shown that the deletion of the mitochondrial arginase isoform, arginase 2 (A2), limits neurovascular injury in models of ischemic retinopathy. Here, we investigated the involvement of A2-mediated alterations in mitochondrial dynamics and function in the pathology. Methods: We used wild-type (WT), global A2 knockout (A2KO-) mice, cell-specific A2 knockout mice subjected to retinal ischemia/reperfusion (I/R), and bovine retinal endothelial cells (BRECs) subjected to an oxygen-glucose deprivation/reperfusion (OGD/R) insult. We used western blotting to measure levels of cell stress and death markers and the mitochondrial fragmentation protein, dynamin related protein 1 (Drp1). We also used live cell mitochondrial labeling and Seahorse XF analysis to evaluate mitochondrial fragmentation and function, respectively. Results: We found that the global deletion of A2 limited the I/R-induced disruption of retinal layers, fundus abnormalities, and albumin extravasation. The specific deletion of A2 in endothelial cells was protective against I/R-induced neurodegeneration. The OGD/R insult in BRECs increased A2 expression and induced cell stress and cell death, along with decreased mitochondrial respiration, increased Drp1 expression, and mitochondrial fragmentation. The overexpression of A2 in BREC also decreased mitochondrial respiration, promoted increases in the expression of Drp1, mitochondrial fragmentation, and cell stress and resulted in decreased cell survival. In contrast, the overexpression of the cytosolic isoform, arginase 1 (A1), did not affect these parameters. Conclusions: This study is the first to show that A2 in endothelial cells mediates retinal ischemic injury through a mechanism involving alterations in mitochondrial dynamics and function.http://www.sciencedirect.com/science/article/pii/S2212877821001186RetinaIschemiaArginaseEndothelial cellsMitochondria
spellingShingle Esraa Shosha
Abdelrahman Y. Fouda
Tahira Lemtalsi
Stephen Haigh
David Fulton
Ahmed Ibrahim
Mohamed Al-Shabrawey
R. William Caldwell
Ruth B. Caldwell
Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction
Molecular Metabolism
Retina
Ischemia
Arginase
Endothelial cells
Mitochondria
title Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction
title_full Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction
title_fullStr Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction
title_full_unstemmed Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction
title_short Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction
title_sort endothelial arginase 2 mediates retinal ischemia reperfusion injury by inducing mitochondrial dysfunction
topic Retina
Ischemia
Arginase
Endothelial cells
Mitochondria
url http://www.sciencedirect.com/science/article/pii/S2212877821001186
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