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Li C, Chen X, Zhang S, Liang C, Deng Q, Li X, Yan H. Pericyte loss via glutaredoxin2 downregulation aggravates diabetes-induced microvascular dysfunction. Exp Eye Res 2024; 247:110025. [PMID: 39117135 DOI: 10.1016/j.exer.2024.110025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 07/16/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
Diabetic retinopathy (DR) is the leading cause of vision loss and blindness among working-age adults. Pericyte loss is an early pathological feature of DR. Under hyperglycemic conditions, reactive oxygen species (ROS) production increases, leading to oxidative stress and subsequent mitochondrial dysfunction and apoptosis. Dysfunctional pericyte can cause retinal vascular leakage, obliteration, and neovascularization. Glutaredoxin 2 (Grx2) is a mitochondrial glutathione-dependent oxidoreductase which protects cells against oxidative insults by safeguarding mitochondrial function. Whether Grx2 plays a protective role in diabetes-induced microvascular dysfunction remains unclear. Our findings revealed that diabetes-related stress reduced Grx2 expression in pericytes, but not in endothelial cells. Grx2 knock-in ameliorated diabetes-induced microvascular dysfunction in vivo DR models. Decreased Grx2 expression led to significant pericyte apoptosis, and pericyte dysfunction, namely reduced pericyte recruitment towards endothelial cells and increased endothelial cell permeability. Conversely, upregulating Grx2 reversed these effects. Furthermore, Grx2 regulated pericyte apoptosis by modulating complex I activity, which is crucial for pericyte mitochondrial function. Overall, our study uncovered a novel mechanism whereby high glucose inhibited Grx2 expression in vivo and in vitro. Grx2 downregulation exacerbated pericyte apoptosis, pericyte dysfunction, and retinal vascular dysfunction by inactivating complex I and mediating mitochondrial dysfunction in pericytes.
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Affiliation(s)
- Chenshuang Li
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Affiliated People's Hospital of Northwest University, Xi'an, 710004, Shaanxi Province, China; Department of Ophthalmology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, China.
| | - Xi Chen
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Affiliated People's Hospital of Northwest University, Xi'an, 710004, Shaanxi Province, China; Institute of Medical Research, Northwestern Polytechnical University, Xi'an, 710072, Shaanxi Province, China.
| | - Siqi Zhang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Affiliated People's Hospital of Northwest University, Xi'an, 710004, Shaanxi Province, China; Department of Ophthalmology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, China.
| | - Chen Liang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Affiliated People's Hospital of Northwest University, Xi'an, 710004, Shaanxi Province, China; Department of Ophthalmology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, China.
| | - Qi Deng
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, 710072, Shaanxi Province, China.
| | - Xinnan Li
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Affiliated People's Hospital of Northwest University, Xi'an, 710004, Shaanxi Province, China; Department of Ophthalmology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, China.
| | - Hong Yan
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Affiliated People's Hospital of Northwest University, Xi'an, 710004, Shaanxi Province, China; Department of Ophthalmology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, China; Institute of Medical Research, Northwestern Polytechnical University, Xi'an, 710072, Shaanxi Province, China.
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Bizjak DA, Ohmayer B, Buhl JL, Schneider EM, Walther P, Calzia E, Jerg A, Matits L, Steinacker JM. Functional and Morphological Differences of Muscle Mitochondria in Chronic Fatigue Syndrome and Post-COVID Syndrome. Int J Mol Sci 2024; 25:1675. [PMID: 38338957 PMCID: PMC10855807 DOI: 10.3390/ijms25031675] [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: 12/21/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Patients suffering from chronic fatigue syndrome (CFS) or post-COVID syndrome (PCS) exhibit a reduced physiological performance capability. Impaired mitochondrial function and morphology may play a pivotal role. Thus, we aimed to measure the muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity and assess mitochondrial morphology in CFS and PCS patients in comparison to healthy controls (HCs). Mitochondrial OXPHOS capacity was measured in permeabilized muscle fibers using high-resolution respirometry. Mitochondrial morphology (subsarcolemmal/intermyofibrillar mitochondrial form/cristae/diameter/circumference/area) and content (number and proportion/cell) were assessed via electron microscopy. Analyses included differences in OXPHOS between HC, CFS, and PCS, whereas comparisons in morphology/content were made for CFS vs. PCS. OXPHOS capacity of complex I, which was reduced in PCS compared to HC. While the subsarcolemmal area, volume/cell, diameter, and perimeter were higher in PCS vs. CFS, no difference was observed for these variables in intermyofibrillar mitochondria. Both the intermyofibrillar and subsarcolemmal cristae integrity was higher in PCS compared to CFS. Both CFS and PCS exhibit increased fatigue and impaired mitochondrial function, but the progressed pathological morphological changes in CFS suggest structural changes due to prolonged inactivity or unknown molecular causes. Instead, the significantly lower complex I activity in PCS suggests probably direct virus-induced alterations.
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Affiliation(s)
- Daniel Alexander Bizjak
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany (J.L.B.); (A.J.); (L.M.); (J.M.S.)
| | - Birgit Ohmayer
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany (J.L.B.); (A.J.); (L.M.); (J.M.S.)
| | - Jasmine Leonike Buhl
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany (J.L.B.); (A.J.); (L.M.); (J.M.S.)
| | | | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, 89081 Ulm, Germany;
| | - Enrico Calzia
- Institute for Anaesthesiologic Pathophysiology and Process Engineering, Ulm University, 89081 Ulm, Germany;
| | - Achim Jerg
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany (J.L.B.); (A.J.); (L.M.); (J.M.S.)
| | - Lynn Matits
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany (J.L.B.); (A.J.); (L.M.); (J.M.S.)
- Clinical & Biological Psychology, Institute of Psychology and Education, Ulm University, 89081 Ulm, Germany
| | - Jürgen Michael Steinacker
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany (J.L.B.); (A.J.); (L.M.); (J.M.S.)
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Aboouf MA, Thiersch M, Soliz J, Gassmann M, Schneider Gasser EM. The Brain at High Altitude: From Molecular Signaling to Cognitive Performance. Int J Mol Sci 2023; 24:10179. [PMID: 37373327 DOI: 10.3390/ijms241210179] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/13/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
The brain requires over one-fifth of the total body oxygen demand for normal functioning. At high altitude (HA), the lower atmospheric oxygen pressure inevitably challenges the brain, affecting voluntary spatial attention, cognitive processing, and attention speed after short-term, long-term, or lifespan exposure. Molecular responses to HA are controlled mainly by hypoxia-inducible factors. This review aims to summarize the cellular, metabolic, and functional alterations in the brain at HA with a focus on the role of hypoxia-inducible factors in controlling the hypoxic ventilatory response, neuronal survival, metabolism, neurogenesis, synaptogenesis, and plasticity.
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Affiliation(s)
- Mostafa A Aboouf
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Jorge Soliz
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC G1V 4G5, Canada
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Edith M Schneider Gasser
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC G1V 4G5, Canada
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland
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