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Qaed E, Alyafeai E, Al-Maamari A, Zaky MY, Almoiliqy M, Al-Hamyari B, Qaid A, Yafei S, Aldahmash W, Mahyoub MA, Wang F, Kang L, Tang Z, Zhang J. Uncovering the Therapeutic Potential of Phosphocreatine in Diabetic Retinopathy: Mitigating Mitochondrial Dysfunction and Apoptosis via JAK2/STAT3 Signaling Pathway. J Mol Neurosci 2024; 74:11. [PMID: 38231435 DOI: 10.1007/s12031-023-02175-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 12/11/2023] [Indexed: 01/18/2024]
Abstract
Diabetic retinopathy (DR) stands as a prevalent complication of diabetes mellitus, causing damage to the delicate retinal capillaries and potentially leading to visual impairment. While the exact underlying cause of DR remains elusive, compelling research suggests that mitochondrial energy deficiency and the excessive generation of reactive oxygen species (ROS) play pivotal roles in its pathogenesis. Recognizing that controlling hyperglycemia alone fails to reverse the defects in retinal mitochondria induced by diabetes, current strategies seek to restore mitochondrial function as a means of safeguarding against DR. To address this pressing issue, a comprehensive study was undertaken to explore the potential of phosphocreatine (PCr) in bolstering mitochondrial bioenergetics and providing protection against DR via modulation of the JAK2/STAT3 signaling pathway. Employing rat mitochondria and RGC-5 cells, the investigation meticulously assessed the impact of PCr on ROS production, mitochondrial membrane potential, as well as the expression of crucial apoptotic and JAK2/STAT3 signaling pathway proteins, utilizing cutting-edge techniques such as high-resolution respirometry and western blotting. The remarkable outcomes revealed that PCr exerts a profound protective influence against DR by enhancing mitochondrial function and alleviating diabetes-associated symptoms and biochemical markers. Notably, PCr administration resulted in an upregulation of antiapoptotic proteins, concomitant with a downregulation of proapoptotic proteins and the JAK2/STAT3 signaling pathway. These significant findings firmly establish PCr as a potential therapeutic avenue for combating diabetic retinopathy. By augmenting mitochondrial function and exerting antiapoptotic effects via the JAK2/STAT3 signaling pathway, PCr demonstrates promising efficacy both in vivo and in vitro, particularly in counteracting the oxidative stress engendered by hyperglycemia. In summary, our study sheds light on the potential of PCr as an innovative therapeutic strategy for diabetic retinopathy. By bolstering mitochondrial function and exerting protective effects via the modulation of the JAK2/STAT3 signaling pathway, PCr holds immense promise in ameliorating the impact of DR in the face of oxidative stress induced by hyperglycemia.
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Grants
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
- LT2013019 The study was supported by the Natural Science Foundation of China (no.30772601) and the University Innovation Team Project Foundation of the Education Department of Liaoning (no. LT2013019).Also,The authors extend their appreciation to the Researchers Supporting Program number (RSPD2023R1080), in King Saud University, Riyadh, Saudi Arabia.
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Affiliation(s)
- Eskandar Qaed
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Eman Alyafeai
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Ahmed Al-Maamari
- The Key Laboratory of Neural and Vascular Biology, The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Ministry of Education, Hebei Medical University, Shijiazhuang, China
| | - Mohamed Y Zaky
- Molecular Physiology Division, Zoology Department, Faculty of Science, Beni-Suef University, P.O. Box 62521, Beni-Suef, Egypt
| | - Marwan Almoiliqy
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China
| | - Bandar Al-Hamyari
- School of Pharmacy & State Key Laboratory of Applied Organic Chemistry, Lanzhou University, 730000, Lanzhou, People's Republic of China
| | - Abdullah Qaid
- N.I. Pirogov Russian National Research Medical University, Moscow, Russia
| | - Saeed Yafei
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China
| | - Waleed Aldahmash
- Zoology Department, College of Science, King Saud University, P. O. Box 2455, 11451, Riyadh, Saudi Arabia
| | - Mueataz A Mahyoub
- Department of Gastroenterology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Fuhan Wang
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China
| | - Le Kang
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China
| | - Zeyao Tang
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China.
| | - Jianbin Zhang
- Department of Pharmacology, Dalian Medical University, 9 West Section, South Road of Lushun, 116044, Dalian, China.
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2
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Li S, Sun D, Chen S, Zhang S, Gu Q, Shen Y, Xu L, Xu X, Wei F, Wang N. UCP2-SIRT3 Signaling Relieved Hyperglycemia-Induced Oxidative Stress and Senescence in Diabetic Retinopathy. Invest Ophthalmol Vis Sci 2024; 65:14. [PMID: 38175638 PMCID: PMC10774691 DOI: 10.1167/iovs.65.1.14] [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: 05/04/2023] [Accepted: 11/09/2023] [Indexed: 01/05/2024] Open
Abstract
Purpose Diabetic retinopathy (DR) is one of the most common reasons for blindness. uncoupling protein 2 (UCP2), an uncoupling protein located in mitochondria, has been reported to be related to metabolic and vascular diseases. This research aimed to illustrate the function and mechanism of UCP2 in the pathogenesis of DR. Methods Human epiretinal membranes were collected to investigate the expression of UCP2 by quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence. Primary human retinal microvascular endothelial cells (HRECs) were cultured in high glucose (HG) to establish an in vitro cell model for DR. Flow cytometry analysis was used to measure intracellular reactive oxygen species (ROS). Senescence levels were evaluated by the senescence-associated beta-galactosidase (SA-β-gal) assay, the expression of senescence marker P21, and cell-cycle analysis. Adenovirus-mediated UCP2 overexpression or knockdown and specific inhibitors were administered to investigate the underlying regulatory mechanism. Results Proliferative fibrovascular membranes from patients with DR illustrated the downregulation of UCP2 and sirtuin 3 (SIRT3) by qRT-PCR and immunofluorescence. Persistent hyperglycemia-induced UCP2 downregulation in the progress of DR and adenovirus-mediated UCP2 overexpression protected endothelial cells from hyperglycemia-induced oxidative stress and senescence. Under hyperglycemic conditions, UCP2 overexpression attenuated NAD+ downregulation; hence, it promoted the expression and activity of SIRT3, an NAD+-dependent deacetylase regulating mitochondrial function. 3-TYP, a selective SIRT3 inhibitor, abolished the UCP2-mediated protective effect against oxidative stress and senescence. Conclusions UCP2 overexpression relieved oxidative stress and senescence based on a novel mechanism whereby UCP2 can regulate the NAD+-SIRT3 axis. Targeting oxidative stress and senescence amelioration, UCP2-SIRT3 signaling may serve as a method for the prevention and treatment of DR and other diabetic vascular diseases.
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Affiliation(s)
- Shenping Li
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Dandan Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Shimei Chen
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Shuchang Zhang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Qing Gu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
| | - Yinchen Shen
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Li Xu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Xun Xu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Fang Wei
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Ning Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
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3
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Serikbaeva A, Li Y, Ganesh B, Zelkha R, Kazlauskas A. Hyperglycemia Promotes Mitophagy and Thereby Mitigates Hyperglycemia-Induced Damage. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:1779-1794. [PMID: 36063899 PMCID: PMC9765315 DOI: 10.1016/j.ajpath.2022.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/02/2022] [Accepted: 08/17/2022] [Indexed: 12/31/2022]
Abstract
The observation that diabetic retinopathy (DR) typically takes decades to develop suggests the existence of an endogenous system that protects from diabetes-induced damage. To investigate the existance of such a system, primary human retinal endothelial cells were cultured in either normal glucose (5 mmol/L) or high glucose (30 mmol/L; HG). Prolonged exposure to HG was beneficial instead of detrimental. Although tumor necrosis factor-α-induced expression of vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 was unaffected after 1 day of HG, it waned as the exposure to HG was extended. Similarly, oxidative stress-induced death decreased with prolonged exposure to HG. Furthermore, mitochondrial functionality, which was compromised by 1 day of HG, was improved by 10 days of HG, and this change required increased clearance of damaged mitochondria (mitophagy). Finally, antagonizing mitochondrial dynamics compromised the cells' ability to endure HG: susceptibility to cell death increased, and basal barrier function and responsiveness to vascular endothelial growth factor deteriorated. These observations indicate the existence of an endogenous system that protects human retinal endothelial cells from the deleterious effects of HG. Hyperglycemia-induced mitochondrial adaptation is a plausible contributor to the mechanism responsible for the delayed onset of DR; loss of hyperglycemia-induced mitochondrial adaptation may set the stage for the development of DR.
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Affiliation(s)
- Anara Serikbaeva
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Yueru Li
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Balaji Ganesh
- Research Resources Center, University of Illinois at Chicago, Chicago, Illinois
| | - Ruth Zelkha
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Andrius Kazlauskas
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois.
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4
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Greiner JV, Glonek T. Intracellular ATP Concentration and Implication for Cellular Evolution. BIOLOGY 2021; 10:1166. [PMID: 34827159 PMCID: PMC8615055 DOI: 10.3390/biology10111166] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 12/12/2022]
Abstract
Crystalline lens and striated muscle exist at opposite ends of the metabolic spectrum. Lens is a metabolically quiescent tissue, whereas striated muscle is a mechanically dynamic tissue with high-energy requirements, yet both tissues contain millimolar levels of ATP (>2.3 mM), far exceeding their underlying metabolic needs. We explored intracellular concentrations of ATP across multiple cells, tissues, species, and domains to provide context for interpreting lens/striated muscle data. Our database revealed that high intracellular ATP concentrations are ubiquitous across diverse life forms including species existing from the Precambrian Era, suggesting an ancient highly conserved role for ATP, independent of its widely accepted view as primarily "metabolic currency". Our findings reinforce suggestions that the primordial function of ATP was non-metabolic in nature, serving instead to prevent protein aggregation.
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Affiliation(s)
- Jack V. Greiner
- The Schepens Eye Research Institute of Massachusetts Eye & Ear Infirmary, Boston, MA 02114, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
- Clinical Eye Research of Boston, Boston, MA 02114, USA;
| | - Thomas Glonek
- Clinical Eye Research of Boston, Boston, MA 02114, USA;
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5
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Hass DT, Barnstable CJ. Uncoupling proteins in the mitochondrial defense against oxidative stress. Prog Retin Eye Res 2021; 83:100941. [PMID: 33422637 DOI: 10.1016/j.preteyeres.2021.100941] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/28/2020] [Accepted: 01/03/2021] [Indexed: 02/06/2023]
Abstract
Oxidative stress is a major component of most major retinal diseases. Many extrinsic anti-oxidative strategies have been insufficient at counteracting one of the predominant intrinsic sources of reactive oxygen species (ROS), mitochondria. The proton gradient across the inner mitochondrial membrane is a key driving force for mitochondrial ROS production, and this gradient can be modulated by members of the mitochondrial uncoupling protein (UCP) family. Of the UCPs, UCP2 shows a widespread distribution and has been shown to uncouple oxidative phosphorylation, with concomitant decreases in ROS production. Genetic studies using transgenic and knockout mice have documented the ability of increased UCP2 activity to provide neuroprotection in models of a number of diseases, including retinal diseases, indicating that it is a strong candidate for a therapeutic target. Molecular studies have identified the structural mechanism of action of UCP2 and have detailed the ways in which its expression and activity can be controlled at the transcriptional, translational and posttranslational levels. These studies suggest a number of ways in control of UCP2 expression and activity can be used therapeutically for both acute and chronic conditions. The development of such therapeutic approaches will greatly increase the tools available to combat a broad range of serious retinal diseases.
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Affiliation(s)
- Daniel T Hass
- Department of Biochemistry, The University of Washington, Seattle, WA, 98109, USA
| | - Colin J Barnstable
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA.
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Holody C, Anfray A, Mast H, Lessard M, Han WH, Carpenter R, Bourque S, Sauvé Y, Lemieux H. Differences in relative capacities of oxidative phosphorylation pathways may explain sex- and tissue-specific susceptibility to vision defects due to mitochondrial dysfunction. Mitochondrion 2020; 56:102-110. [PMID: 33271347 DOI: 10.1016/j.mito.2020.11.013] [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: 07/21/2020] [Revised: 10/09/2020] [Accepted: 11/18/2020] [Indexed: 01/03/2023]
Abstract
Mitochondrial dysfunction is a major cause and/or contributor to the development and progression of vision defects in many ophthalmologic and mitochondrial diseases. Despite their mechanistic commonality, these diseases exhibit an impressive variety in sex- and tissue-specific penetrance, incidence, and severity. Currently, there is no functional explanation for these differences. We measured the function, relative capacities, and patterns of control of various oxidative phosphorylation pathways in the retina, the eyecup, the extraocular muscles, the optic nerve, and the sciatic nerve of adult male and female rats. We show that the control of mitochondrial respiratory pathways in the visual system is sex- and tissue-specific and that this may be an important factor in determining susceptibility to mitochondrial dysfunction between these groups. The optic nerve showed a low relative capacity of the NADH pathway, depending on complex I, compared to other tissues relying mainly on mitochondria for energy production. Furthermore, NADH pathway capacity is higher in females compared to males, and this sexual dimorphism occurs only in the optic nerve. Our results propose an explanation for Leber's hereditary optic neuropathy, a mitochondrial disease more prevalent in males where the principal tissue affected is the optic nerve. To our knowledge, this is the first study to identify and provide functional explanations for differences in the occurrence and severity of visual defects between tissues and between sexes. Our results highlight the importance of considering sex- and tissue-specific mitochondrial function in elucidating pathophysiological mechanisms of visual defects.
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Affiliation(s)
- Claudia Holody
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada; Dept. of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Anaïs Anfray
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Heather Mast
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Martin Lessard
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Woo Hyun Han
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Rowan Carpenter
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Stephane Bourque
- Dept. of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Yves Sauvé
- Dept. of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Hélène Lemieux
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Medicine, University of Alberta, Edmonton, Alberta, Canada.
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7
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Diabetic Retinopathy: The Role of Mitochondria in the Neural Retina and Microvascular Disease. Antioxidants (Basel) 2020; 9:antiox9100905. [PMID: 32977483 PMCID: PMC7598160 DOI: 10.3390/antiox9100905] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Diabetic retinopathy (DR), a common chronic complication of diabetes mellitus and the leading cause of vision loss in the working-age population, is clinically defined as a microvascular disease that involves damage of the retinal capillaries with secondary visual impairment. While its clinical diagnosis is based on vascular pathology, DR is associated with early abnormalities in the electroretinogram, indicating alterations of the neural retina and impaired visual signaling. The pathogenesis of DR is complex and likely involves the simultaneous dysregulation of multiple metabolic and signaling pathways through the retinal neurovascular unit. There is evidence that microvascular disease in DR is caused in part by altered energetic metabolism in the neural retina and specifically from signals originating in the photoreceptors. In this review, we discuss the main pathogenic mechanisms that link alterations in neural retina bioenergetics with vascular regression in DR. We focus specifically on the recent developments related to alterations in mitochondrial metabolism including energetic substrate selection, mitochondrial function, oxidation-reduction (redox) imbalance, and oxidative stress, and critically discuss the mechanisms of these changes and their consequences on retinal function. We also acknowledge implications for emerging therapeutic approaches and future research directions to find novel mitochondria-targeted therapeutic strategies to correct bioenergetics in diabetes. We conclude that retinal bioenergetics is affected in the early stages of diabetes with consequences beyond changes in ATP content, and that maintaining mitochondrial integrity may alleviate retinal disease.
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8
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Ramírez-Pérez G, Sánchez-Chávez G, Salceda R. Mitochondrial bound hexokinase type I in normal and streptozotocin diabetic rat retina. Mitochondrion 2020; 52:212-217. [DOI: 10.1016/j.mito.2020.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/24/2020] [Accepted: 04/07/2020] [Indexed: 12/19/2022]
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9
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Shivashankar G, Lim JC, Acosta ML. Proinflammatory cytokines trigger biochemical and neurochemical changes in mouse retinal explants exposed to hyperglycemic conditions. Mol Vis 2020; 26:277-290. [PMID: 32300272 PMCID: PMC7155896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 04/09/2020] [Indexed: 12/04/2022] Open
Abstract
PURPOSE Diabetic retinopathy (DR) is one of the most frequent complications of diabetes affecting the retina and eventually causing vision impairment. Emerging evidence suggests that inflammation plays a vital role in DR progression. In this study, we evaluated the early biochemical and neurochemical changes in mouse retinal explants to understand the contribution of proinflammatory cytokines to disease progression. METHODS DR was modeled in vitro by incubating mouse retinal explants in a physiological buffer supplemented with high glucose and the proinflammatory cytokines TNF-α and IL-1β. Key metabolites of retinal energy metabolism, including glucose, lactate, ATP, glutamate, glutamine, and enzymes supporting retinal ATP levels were assessed 40 min after the application of high glucose and proinflammatory cytokines. As retinal energy metabolism is tightly coupled to retinal neurochemistry, we also determined the short-term effect on the amino acid distribution of glutamate, gamma aminobutyric acid (GABA), glutamine, and glycine. RESULTS The results indicated that the combined application of high glucose and proinflammatory cytokines increased retinal glucose, lactate, and ATP levels, and decreased retinal glutamate, without affecting glutamine levels or the enzymes supporting ATP levels. Moreover, we observed a statistically significant increase in ATP and glutamate release. Correspondingly, statistically significant alterations in amino acid distribution were observed in retinal explants coexposed to high glucose and proinflammatory cytokines. CONCLUSIONS These data suggest that short-term exposure to proinflammatory cytokines contributes to the early biochemical and neurochemical changes caused by hyperglycemia, by affecting retinal energy metabolism and amino acid distribution. These data are consistent with the idea that early intervention to prevent inflammation-triggered loss of metabolic homeostasis in patients with diabetes is necessary to prevent DR progression.
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Affiliation(s)
- Gaganashree Shivashankar
- School of Optometry and Vision Science and New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Julie C. Lim
- Department of Physiology, School of Medical and Health Sciences and New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Monica L. Acosta
- School of Optometry and Vision Science and New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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10
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Mitochondrial Structural Changes in the Pathogenesis of Diabetic Retinopathy. J Clin Med 2019; 8:jcm8091363. [PMID: 31480638 PMCID: PMC6780143 DOI: 10.3390/jcm8091363] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 08/27/2019] [Accepted: 08/29/2019] [Indexed: 12/24/2022] Open
Abstract
At the core of proper mitochondrial functionality is the maintenance of its structure and morphology. Physical changes in mitochondrial structure alter metabolic pathways inside mitochondria, affect mitochondrial turnover, disturb mitochondrial dynamics, and promote mitochondrial fragmentation, ultimately triggering apoptosis. In high glucose condition, increased mitochondrial fragmentation contributes to apoptotic death in retinal vascular and Müller cells. Although alterations in mitochondrial morphology have been detected in several diabetic tissues, it remains to be established in the vascular cells of the diabetic retina. From a mechanistic standpoint, our current work supports the notion that increased expression of fission genes and decreased expression of fusion genes are involved in promoting excessive mitochondrial fragmentation. While mechanistic insights are only beginning to reveal how high glucose alters mitochondrial morphology, the consequences are clearly seen as release of cytochrome c from fragmented mitochondria triggers apoptosis. Current findings raise the prospect of targeting excessive mitochondrial fragmentation as a potential therapeutic strategy for treatment of diabetic retinopathy. While biochemical and epigenetic changes have been reported to be associated with mitochondrial dysfunction, this review focuses on alterations in mitochondrial morphology, and their impact on mitochondrial function and pathogenesis of diabetic retinopathy.
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11
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Hinder LM, Sas KM, O'Brien PD, Backus C, Kayampilly P, Hayes JM, Lin CM, Zhang H, Shanmugam S, Rumora AE, Abcouwer SF, Brosius FC, Pennathur S, Feldman EL. Mitochondrial uncoupling has no effect on microvascular complications in type 2 diabetes. Sci Rep 2019; 9:881. [PMID: 30696927 PMCID: PMC6351661 DOI: 10.1038/s41598-018-37376-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/28/2018] [Indexed: 12/30/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN), diabetic kidney disease (DKD), and diabetic retinopathy (DR) contribute to significant morbidity and mortality in diabetes patients. The incidence of these complications is increasing with the diabetes epidemic, and current therapies minimally impact their pathogenesis in type 2 diabetes (T2D). Improved mechanistic understanding of each of the diabetic complications is needed in order to develop disease-modifying treatments for patients. We recently identified fundamental differences in mitochondrial responses of peripheral nerve, kidney, and retinal tissues to T2D in BKS-db/db mice. However, whether these mitochondrial adaptations are the cause or consequence of tissue dysfunction remains unclear. In the current study BKS-db/db mice were treated with the mitochondrial uncoupler, niclosamide ethanolamine (NEN), to determine the effects of mitochondrial uncoupling therapy on T2D, and the pathogenesis of DPN, DKD and DR. Here we report that NEN treatment from 6-24 wk of age had little effect on the development of T2D and diabetic complications. Our data suggest that globally targeting mitochondria with an uncoupling agent is unlikely to provide therapeutic benefit for DPN, DKD, or DR in T2D. These data also highlight the need for further insights into the role of tissue-specific metabolic reprogramming in the pathogenesis of diabetic complications.
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Affiliation(s)
- Lucy M Hinder
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kelli M Sas
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Phillipe D O'Brien
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carey Backus
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Pradeep Kayampilly
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - John M Hayes
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Cheng-Mao Lin
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Hongyu Zhang
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Sumathi Shanmugam
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Amy E Rumora
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Steven F Abcouwer
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Frank C Brosius
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA.
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12
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Determination of Mitochondrial Oxygen Consumption in the Retina Ex Vivo: Applications for Retinal Disease. Methods Mol Biol 2019; 1753:167-177. [PMID: 29564788 DOI: 10.1007/978-1-4939-7720-8_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Mitochondrial dysfunction, and consequently altered aerobic energy metabolism, is associated with numerous retinal diseases, including photoreceptor degeneration and diabetic retinopathy. Here, we describe a detailed protocol to directly measure oxygen consumption in the intact retina ex vivo using microplate-based fluorescence technology. We have used this method to assess preferred energy substrate for retinal tissue and suggested its application for investigating mechanisms of retinal disease.
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13
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Yin J, Ren W, Chen S, Li Y, Han H, Gao J, Liu G, Wu X, Li T, Woo Kim S, Yin Y. Metabolic Regulation of Methionine Restriction in Diabetes. Mol Nutr Food Res 2018; 62:e1700951. [PMID: 29603632 DOI: 10.1002/mnfr.201700951] [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] [Received: 11/19/2017] [Revised: 01/25/2018] [Indexed: 12/16/2022]
Abstract
Although the effects of dietary methionine restriction have been investigated in the physiology of aging and diseases related to oxidative stress, the relationship between methionine restriction (MR) and the development of metabolic disorders has not been explored extensively. This review summarizes studies of the possible involvement of dietary methionine restriction in improving insulin resistance, glucose homeostasis, oxidative stress, lipid metabolism, the pentose phosphate pathway (PPP), and inflammation, with an emphasis on the fibroblast growth factor 21 and protein phosphatase 2A signals and autophagy in diabetes. Diets deficient in methionine may be a useful nutritional strategy in patients with diabetes.
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Affiliation(s)
- Jie Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Wenkai Ren
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product, Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shuai Chen
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Yuying Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Hui Han
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Jing Gao
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Gang Liu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Xin Wu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
| | - Tiejun Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
| | - Sung Woo Kim
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | - Yulong Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
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14
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The Oxidative Stress and Mitochondrial Dysfunction during the Pathogenesis of Diabetic Retinopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:3420187. [PMID: 30254714 PMCID: PMC6145164 DOI: 10.1155/2018/3420187] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/27/2018] [Accepted: 08/14/2018] [Indexed: 12/14/2022]
Abstract
Diabetic retinopathy is one of the most serious microvascular complications induced by hyperglycemia via five major pathways, including polyol, hexosamine, protein kinase C, and angiotensin II pathways and the accumulation of advanced glycation end products. The hyperglycemia-induced overproduction of reactive oxygen species (ROS) induces local inflammation, mitochondrial dysfunction, microvascular dysfunction, and cell apoptosis. The accumulation of ROS, local inflammation, and cell death are tightly linked and considerably affect all phases of diabetic retinopathy pathogenesis. Furthermore, microvascular dysfunction induces ischemia and local inflammation, leading to neovascularization, macular edema, and neurodysfunction, ultimately leading to long-term blindness. Therefore, it is crucial to understand and elucidate the detailed mechanisms underlying the development of diabetic retinopathy. In this review, we summarized the existing knowledge about the pathogenesis and current strategies for the treatment of diabetic retinopathy, and we believe this systematization will help and support further research in this area.
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15
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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16
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Osorio-Paz I, Ramírez-Pérez G, Hernández-Ramírez JE, Uribe-Carvajal S, Salceda R. Mitochondrial activity in different regions of the brain at the onset of streptozotocin-induced diabetes in rats. Mol Biol Rep 2018; 45:871-879. [PMID: 29982890 DOI: 10.1007/s11033-018-4233-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/29/2018] [Indexed: 12/31/2022]
Abstract
Diabetes affects a variety of tissues including the central nervous system; moreover, some evidence indicates that memory and learning processes are disrupted. Also, oxidative stress triggers alterations in different tissues including the brain. Recent studies indicate mitochondria dysfunction is a pivotal factor for neuron damage. Therefore, we studied mitochondrial activity in three brain regions at early type I-diabetes induction. Isolated mitochondria from normal hippocampus, cortex and cerebellum revealed different rates of oxygen consumption, but similar respiratory controls. Oxygen consumption in basal state 4 significantly increased in the mitochondria from all three brain regions from diabetic rats. No relevant differences were observed in the activity of respiratory complexes, but hippocampal mitochondrial membrane potential was reduced. However, ATP content, mitochondrial cytochrome c, and protein levels of β-tubulin III, synaptophysin, and glutamine synthase were similar in brain regions from normal and diabetic rats. In addition, no differences in total glutathione levels were observed between normal and diabetic rat brain regions. Our results indicated that different regions of the brain have specific metabolic responses. The changes in mitochondrial activity we observed at early diabetes induction did not appear to cause metabolic alterations, but they might appear at later stages. Longer-term streptozotocin treatment studies must be done to elucidate the impact of hyperglycemia in brain metabolism and the function of specific brain regions.
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Affiliation(s)
- Ixchel Osorio-Paz
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, D.F., Mexico
| | - Gabriela Ramírez-Pérez
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, D.F., Mexico
| | - Jesús E Hernández-Ramírez
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, D.F., Mexico
| | - Salvador Uribe-Carvajal
- División de Investigación Básica, Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, D.F., Mexico
| | - Rocío Salceda
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, D.F., Mexico.
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17
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Masser DR, Otalora L, Clark NW, Kinter MT, Elliott MH, Freeman WM. Functional changes in the neural retina occur in the absence of mitochondrial dysfunction in a rodent model of diabetic retinopathy. J Neurochem 2017; 143:595-608. [PMID: 28902411 DOI: 10.1111/jnc.14216] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/24/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022]
Abstract
Diabetic retinopathy is a neurovascular diabetes complication resulting in vision loss. A wealth of literature reports retinal molecular changes indicative of neural deficits, inflammation, and vascular leakage with chronic diabetes, but the mechanistic causes of disease initiation and progression are unknown. Microvascular mitochondrial DNA (mtDNA) damage leading to mitochondrial dysfunction has been proposed to drive vascular dysfunction in retinopathy. However, growing evidence suggests that neural retina dysfunction precedes and may cause vascular damage. Therefore, we tested the hypothesis that neural mtDNA damage and mitochondrial dysfunction are an early initiating factor of neural diabetic retinopathy development in a rat streptozotocin-induced, Type I diabetes model. Mitochondrial function (oxygen consumption rates) was quantified in retinal synaptic terminals from diabetic and non-diabetic rats with paired retinal structural and function assessment (optical coherence tomography and electroretinography, respectively). Mitochondrial genome damage was assessed by identifying mutations and deletions across the mtDNA genome by high depth sequencing and absolute mtDNA copy number counting through digital PCR. Mitochondrial protein expression was assessed by targeted mass spectrometry. Retinal functional deficits and neural anatomical changes were present after 3 months of diabetes and prevented/normalized by insulin treatment. No marked dysfunction of mitochondrial activity, maladaptive changes in mitochondrial protein expression, alterations in mtDNA copy number, or increase in mtDNA damage was observed in conjunction with retinal functional and anatomical changes. These results demonstrate that neural retinal dysfunction with diabetes begins prior to mtDNA damage and dysfunction, and therefore retinal neurodegeneration initiation with diabetes occurs through other, non-mitochondrial DNA damage, mechanisms.
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Affiliation(s)
- Dustin R Masser
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Laura Otalora
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Reynolds Oklahoma Center on Aging, Oklahoma City, Oklahoma, USA.,Oklahoma Nathan Shock Center on Aging, Oklahoma City, Oklahoma, USA
| | - Nicholas W Clark
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Reynolds Oklahoma Center on Aging, Oklahoma City, Oklahoma, USA
| | - Michael T Kinter
- Oklahoma Nathan Shock Center on Aging, Oklahoma City, Oklahoma, USA.,Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Michael H Elliott
- Department of Ophthalmology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Willard M Freeman
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Reynolds Oklahoma Center on Aging, Oklahoma City, Oklahoma, USA.,Oklahoma Nathan Shock Center on Aging, Oklahoma City, Oklahoma, USA
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18
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Sánchez-Chávez G, Hernández-Ramírez E, Osorio-Paz I, Hernández-Espinosa C, Salceda R. Potential Role of Endoplasmic Reticulum Stress in Pathogenesis of Diabetic Retinopathy. Neurochem Res 2015; 41:1098-106. [PMID: 26721508 DOI: 10.1007/s11064-015-1798-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 12/09/2015] [Accepted: 12/09/2015] [Indexed: 01/23/2023]
Abstract
Diabetes mellitus is a metabolic disease that leads to several complications which include retinopathy. Multiple biochemical abnormalities have been proposed to explain the development of retinopathy, including oxidative stress. Although the existence of oxidative stress has been established in the retina from long standing diabetic animals, pathogenesis and progression of retinopathy remain unclear. In order to gain insight into the pathogenesis of diabetic retinopathy, we analyzed the levels of different oxidative stress biomarkers in the retina at early stages during the progress of streptozotocin-induced diabetes. No significant changes in glutathione content, expression of NADPH-oxidase, levels of lipid peroxidation, nor production of free radicals were observed in the retina up to 45 days of diabetes induction. Likewise, a transient decrease in aconitase activity, parallel to an increase in the superoxide dismutase activity was observed at 20 days of hyperglycemia, suggesting a high capacity of retina to maintain its redox homeostasis, at least at early stages of diabetes. Nonetheless, we found an early and time-dependent increase in the levels of oxidized proteins, which was not affected by the administration of the antioxidant quercetin. Also, positive immunoreactivity to the reticulum stress protein CHOP was found in glial Müller cells of diabetic rat retinas. These findings suggest the occurrence of endoplasmic reticulum stress as a primary event in retina pathogenesis in diabetes.
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Affiliation(s)
- Gustavo Sánchez-Chávez
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, CP 04510, Mexico, D. F., Mexico
| | - Ernesto Hernández-Ramírez
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, CP 04510, Mexico, D. F., Mexico
| | - Ixchel Osorio-Paz
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, CP 04510, Mexico, D. F., Mexico
| | - Claudia Hernández-Espinosa
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, CP 04510, Mexico, D. F., Mexico
| | - Rocío Salceda
- División de Neurociencias, Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, CP 04510, Mexico, D. F., Mexico.
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