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Sivagurunathan N, Calivarathan L. SARS-CoV-2 Infection to Premature Neuronal Aging and Neurodegenerative Diseases: Is there any Connection with Hypoxia? CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:431-448. [PMID: 37073650 DOI: 10.2174/1871527322666230418114446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 01/28/2023] [Accepted: 02/09/2023] [Indexed: 04/20/2023]
Abstract
The pandemic of coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, has become a global concern as it leads to a spectrum of mild to severe symptoms and increases death tolls around the world. Severe COVID-19 results in acute respiratory distress syndrome, hypoxia, and multi- organ dysfunction. However, the long-term effects of post-COVID-19 infection are still unknown. Based on the emerging evidence, there is a high possibility that COVID-19 infection accelerates premature neuronal aging and increases the risk of age-related neurodegenerative diseases in mild to severely infected patients during the post-COVID period. Several studies correlate COVID-19 infection with neuronal effects, though the mechanism through which they contribute to the aggravation of neuroinflammation and neurodegeneration is still under investigation. SARS-CoV-2 predominantly targets pulmonary tissues and interferes with gas exchange, leading to systemic hypoxia. The neurons in the brain require a constant supply of oxygen for their proper functioning, suggesting that they are more vulnerable to any alteration in oxygen saturation level that results in neuronal injury with or without neuroinflammation. We hypothesize that hypoxia is one of the major clinical manifestations of severe SARS-CoV-2 infection; it directly or indirectly contributes to premature neuronal aging, neuroinflammation, and neurodegeneration by altering the expression of various genes responsible for the survival of the cells. This review focuses on the interplay between COVID-19 infection, hypoxia, premature neuronal aging, and neurodegenerative diseases and provides a novel insight into the molecular mechanisms of neurodegeneration.
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Affiliation(s)
- Narmadhaa Sivagurunathan
- Molecular Pharmacology & Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur - 610005, Tamil Nadu, India
| | - Latchoumycandane Calivarathan
- Molecular Pharmacology & Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur - 610005, Tamil Nadu, India
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Liu J, Gu Y, Guo M, Ji X. Neuroprotective effects and mechanisms of ischemic/hypoxic preconditioning on neurological diseases. CNS Neurosci Ther 2021; 27:869-882. [PMID: 34237192 PMCID: PMC8265941 DOI: 10.1111/cns.13642] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022] Open
Abstract
As the organ with the highest demand for oxygen, the brain has a poor tolerance to ischemia and hypoxia. Despite severe ischemia/hypoxia induces the occurrence and development of various central nervous system (CNS) diseases, sublethal insult may induce strong protection against subsequent fatal injuries by improving tolerance. Searching for potential measures to improve brain ischemic/hypoxic is of great significance for treatment of ischemia/hypoxia related CNS diseases. Ischemic/hypoxic preconditioning (I/HPC) refers to the approach to give the body a short period of mild ischemic/hypoxic stimulus which can significantly improve the body's tolerance to subsequent more severe ischemia/hypoxia event. It has been extensively studied and been considered as an effective therapeutic strategy in CNS diseases. Its protective mechanisms involved multiple processes, such as activation of hypoxia signaling pathways, anti-inflammation, antioxidant stress, and autophagy induction, etc. As a strategy to induce endogenous neuroprotection, I/HPC has attracted extensive attention and become one of the research frontiers and hotspots in the field of neurotherapy. In this review, we discuss the basic and clinical research progress of I/HPC on CNS diseases, and summarize its mechanisms. Furthermore, we highlight the limitations and challenges of their translation from basic research to clinical application.
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Affiliation(s)
- Jia Liu
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Yakun Gu
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Mengyuan Guo
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Xunming Ji
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China.,Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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Neuroinflammation: An Integrating Overview of Reactive-Neuroimmune Cell Interactions in Health and Disease. Mediators Inflamm 2021; 2021:9999146. [PMID: 34158806 PMCID: PMC8187052 DOI: 10.1155/2021/9999146] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 05/04/2021] [Indexed: 12/14/2022] Open
Abstract
The concept of central nervous system (CNS) inflammation has evolved over the last decades. Neuroinflammation is the response of reactive CNS components to altered homeostasis, regardless of the cause to be endogenous or exogenous. Neurological diseases, whether traumatic, neoplastic, ischemic, metabolic, toxic, infectious, autoimmune, developmental, or degenerative, involve direct and indirect immune-related neuroinflammation. Brain infiltrates of the innate and adaptive immune system cells appear in response to an infective or otherwise noxious agent and produce inflammatory mediators. Mediators of inflammation include local and recruited cells and signals. Processes derived from extrinsic and intrinsic CNS diseases also elicit the CNS inflammatory response. A deeper understanding of immune-related inflammation in health and disease is necessary to find potential therapeutic targets for preventing or reducing CNS damage. This review is aimed at discussing the innate and adaptive immune system functions and their roles in regulating brain cell responses in disease and homeostasis maintenance.
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Halder SK, Milner R. Hypoxia in multiple sclerosis; is it the chicken or the egg? Brain 2021; 144:402-410. [PMID: 33351069 PMCID: PMC8453297 DOI: 10.1093/brain/awaa427] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/03/2020] [Accepted: 10/14/2020] [Indexed: 12/22/2022] Open
Abstract
Over the past 50 years, intense research effort has taught us a great deal about multiple sclerosis. We know that it is the most common neurological disease affecting the young-middle aged, that it affects two to three times more females than males, and that it is characterized as an autoimmune disease, in which autoreactive T lymphocytes cross the blood-brain barrier, resulting in demyelinating lesions. But despite all the knowledge gained, a key question still remains; what is the initial event that triggers the inflammatory demyelinating process? While most research effort to date has focused on the immune system, more recently, another potential candidate has emerged: hypoxia. Specifically, a growing number of studies have described the presence of hypoxia (both 'virtual' and real) at an early stage of demyelinating lesions, and several groups, including our own, have begun to investigate how manipulation of inspired oxygen levels impacts disease progression. In this review we summarize the findings of these hypoxia studies, and in particular, address three main questions: (i) is the hypoxia found in demyelinating lesions 'virtual' or real; (ii) what causes this hypoxia; and (iii) how does manipulation of inspired oxygen impact disease progression?
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Affiliation(s)
- Sebok K Halder
- San Diego Biomedical Research Institute, 10865 Road to the Cure, Suite 100, San Diego, CA 92121, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, 10865 Road to the Cure, Suite 100, San Diego, CA 92121, USA
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Chronic mild hypoxia accelerates recovery from preexisting EAE by enhancing vascular integrity and apoptosis of infiltrated monocytes. Proc Natl Acad Sci U S A 2020; 117:11126-11135. [PMID: 32371484 DOI: 10.1073/pnas.1920935117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While several studies have shown that hypoxic preconditioning suppresses development of the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS), no one has yet examined the important clinically relevant question of whether mild hypoxia can impact the progression of preexisting disease. Using a relapsing-remitting model of EAE, here we demonstrate that when applied to preexisting disease, chronic mild hypoxia (CMH, 10% O2) markedly accelerates clinical recovery, leading to long-term stable reductions in clinical score. At the histological level, CMH led to significant reductions in vascular disruption, leukocyte accumulation, and demyelination. Spinal cord blood vessels of CMH-treated mice showed reduced expression of the endothelial activation molecule VCAM-1 but increased expression of the endothelial tight junction proteins ZO-1 and occludin, key mechanisms underlying vascular integrity. Interestingly, while equal numbers of inflammatory leukocytes were present in the spinal cord at peak disease (day 14 postimmunization; i.e., 3 d after CMH started), apoptotic removal of infiltrated leukocytes during the remission phase was markedly accelerated in CMH-treated mice, as determined by increased numbers of monocytes positive for TUNEL and cleaved caspase-3. The enhanced monocyte apoptosis in CMH-treated mice was paralleled by increased numbers of HIF-1α+ monocytes, suggesting that CMH enhances monocyte removal by amplifying the hypoxic stress manifest within monocytes in acute inflammatory lesions. These data demonstrate that mild hypoxia promotes recovery from preexisting inflammatory demyelinating disease and suggest that this protection is primarily the result of enhanced vascular integrity and accelerated apoptosis of infiltrated monocytes.
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Malone K, Amu S, Moore AC, Waeber C. Immunomodulatory Therapeutic Strategies in Stroke. Front Pharmacol 2019; 10:630. [PMID: 31281252 PMCID: PMC6595144 DOI: 10.3389/fphar.2019.00630] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 05/16/2019] [Indexed: 12/14/2022] Open
Abstract
The role of immunity in all stages of stroke is increasingly being recognized, from the pathogenesis of risk factors to tissue repair, leading to the investigation of a range of immunomodulatory therapies. In the acute phase of stroke, proposed therapies include drugs targeting pro-inflammatory cytokines, matrix metalloproteinases, and leukocyte infiltration, with a key objective to reduce initial brain cell toxicity. Systemically, the early stages of stroke are also characterized by stroke-induced immunosuppression, where downregulation of host defences predisposes patients to infection. Therefore, strategies to modulate innate immunity post-stroke have garnered greater attention. A complementary objective is to reduce longer-term sequelae by focusing on adaptive immunity. Following stroke onset, the integrity of the blood–brain barrier is compromised, exposing central nervous system (CNS) antigens to systemic adaptive immune recognition, potentially inducing autoimmunity. Some pre-clinical efforts have been made to tolerize the immune system to CNS antigens pre-stroke. Separately, immune cell populations that exhibit a regulatory phenotype (T- and B- regulatory cells) have been shown to ameliorate post-stroke inflammation and contribute to tissue repair. Cell-based therapies, established in oncology and transplantation, could become a strategy to treat the acute and chronic stages of stroke. Furthermore, a role for the gut microbiota in ischaemic injury has received attention. Finally, the immune system may play a role in remote ischaemic preconditioning-mediated neuroprotection against stroke. The development of stroke therapies involving organs distant to the infarct site, therefore, should not be overlooked. This review will discuss the immune mechanisms of various therapeutic strategies, surveying published data and discussing more theoretical mechanisms of action that have yet to be exploited.
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Affiliation(s)
- Kyle Malone
- Department of Pharmacology and Therapeutics, School of Pharmacy, University College Cork, Cork, Ireland
| | - Sylvie Amu
- Cancer Research @UCC, University College Cork, Cork, Ireland
| | - Anne C Moore
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Christian Waeber
- Department of Pharmacology and Therapeutics, School of Pharmacy, University College Cork, Cork, Ireland
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Halder SK, Kant R, Milner R. Chronic mild hypoxia increases expression of laminins 111 and 411 and the laminin receptor α6β1 integrin at the blood-brain barrier. Brain Res 2018; 1700:78-85. [PMID: 30006296 PMCID: PMC6231956 DOI: 10.1016/j.brainres.2018.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 11/23/2022]
Abstract
The laminin family of glycoproteins are major constituents of the basal lamina of blood vessels, and play a fundamental role in promoting endothelial differentiation and blood-brain barrier (BBB) stability. Chronic mild hypoxia (CMH), in which mice are exposed to 8% O2 for two weeks, induces a strong vascular remodeling response in the central nervous system (CNS) that includes endothelial proliferation, angiogenesis, arteriogenesis as well as increased expression of tight junction proteins, suggestive of enhanced vascular integrity. As previous studies highlight an important role for laminin in promoting vascular differentiation and BBB stability, the goal of this study was to determine if CMH influences the expression of the laminins and their cell surface receptors in cerebral blood vessels. Our studies revealed that over a 14 day period of CMH, blood vessels in the brain showed strong upregulation of the specific laminin subunits α1 and α4, corresponding to increased expression of laminins 111 and 411 respectively, with no discernible changes in the expression levels of the α2 or α5 laminin subunits. This was accompanied by marked endothelial upregulation of the laminin receptor α6β1 integrin but no alterations in the other laminin receptors α1β1 integrin or dystroglycan. In light of the instructive role for laminins in promoting vascular differentiation and stability, these data suggest that upregulation of the laminin-α6β1 integrin axis is part of the molecular response triggered by mild hypoxia that leads to enhanced BBB stability.
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Affiliation(s)
- Sebok K Halder
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States.
| | - Ravi Kant
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States.
| | - Richard Milner
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States.
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Halder SK, Kant R, Milner R. Hypoxic pre-conditioning suppresses experimental autoimmune encephalomyelitis by modifying multiple properties of blood vessels. Acta Neuropathol Commun 2018; 6:86. [PMID: 30176931 PMCID: PMC6122733 DOI: 10.1186/s40478-018-0590-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 08/27/2018] [Indexed: 12/26/2022] Open
Abstract
While hypoxic pre-conditioning protects against neurological disease the underlying mechanisms have yet to be fully defined. As chronic mild hypoxia (CMH, 10% O2) triggers profound vascular remodeling in the central nervous system (CNS), the goal of this study was to examine the protective potential of hypoxic pre-conditioning in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS) and then determine how CMH influences vascular integrity and the underlying cellular and molecular mechanisms during EAE. We found that mice exposed to CMH at the same time as EAE induction were strongly protected against the development of EAE progression, as assessed both at the clinical level and at the histopathological level by reduced levels of inflammatory leukocyte infiltration, vascular breakdown and demyelination. Mechanistically, our studies indicate that CMH protects, at least in part, by enhancing several properties of blood vessels that contribute to vascular integrity, including reduced expression of the endothelial activation molecules VCAM-1 and ICAM-1, maintained expression of endothelial tight junction proteins ZO-1 and occludin, and upregulated expression of the leukocyte inhibitory protein laminin-111 in the vascular basement membrane. Taken together, these data suggest that optimization of BBB integrity is an important mechanism underlying the protective effect of hypoxic pre-conditioning.
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Camara-Lemarroy CR, Metz L, Smith EE, Dunn JF, Yong VW. Expanding the Potential Therapeutic Options for Remote Ischemic Preconditioning: Use in Multiple Sclerosis. Front Neurol 2018; 9:475. [PMID: 29971043 PMCID: PMC6018107 DOI: 10.3389/fneur.2018.00475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/01/2018] [Indexed: 12/11/2022] Open
Affiliation(s)
- Carlos R Camara-Lemarroy
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,UANL School of Medicine and University Hospital, Monterrey, Mexico
| | - Luanne Metz
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Eric E Smith
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jeff F Dunn
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - V Wee Yong
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Abstract
Increasing evidence suggests a key role for tissue energy failure in the pathophysiology of multiple sclerosis (MS). Studies in experimental autoimmune encephalomyelitis (EAE), a commonly used model of MS, have been instrumental in illuminating the mechanisms that may be involved in compromising energy production. In this article, we review recent advances in EAE research focussing on factors that conspire to impair tissue energy metabolism, such as tissue hypoxia, mitochondrial dysfunction, production of reactive oxygen/nitrogen species, and sodium dysregulation, which are directly affected by energy insufficiency, and promote cellular damage. A greater understanding of how inflammation affects tissue energy balance may lead to novel and effective therapeutic strategies that ultimately will benefit not only people affected by MS but also people affected by the wide range of other neurological disorders in which neuroinflammation plays an important role.
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Affiliation(s)
- Roshni A Desai
- Department of Neuroinflammation, UCL Institute of Neurology, London, UK
| | - Kenneth J Smith
- Department of Neuroinflammation, UCL Institute of Neurology, London, UK
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Cancer acidity: An ultimate frontier of tumor immune escape and a novel target of immunomodulation. Semin Cancer Biol 2017; 43:74-89. [PMID: 28267587 DOI: 10.1016/j.semcancer.2017.03.001] [Citation(s) in RCA: 360] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/22/2017] [Accepted: 03/01/2017] [Indexed: 12/21/2022]
Abstract
The link between cancer metabolism and immunosuppression, inflammation and immune escape has generated major interest in investigating the effects of low pH on tumor immunity. Indeed, microenvironmental acidity may differentially impact on diverse components of tumor immune surveillance, eventually contributing to immune escape and cancer progression. Although the molecular pathways underlying acidity-related immune dysfunctions are just emerging, initial evidence indicates that antitumor effectors such as T and NK cells tend to lose their function and undergo a state of mostly reversible anergy followed by apoptosis, when exposed to low pH environment. At opposite, immunosuppressive components such as myeloid cells and regulatory T cells are engaged by tumor acidity to sustain tumor growth while blocking antitumor immune responses. Local acidity could also profoundly influence bioactivity and distribution of antibodies, thus potentially interfering with the clinical efficacy of therapeutic antibodies including immune checkpoint inhibitors. Hence tumor acidity is a central regulator of cancer immunity that orchestrates both local and systemic immunosuppression and that may offer a broad panel of therapeutic targets. This review outlines the fundamental pathways of acidity-driven immune dysfunctions and sheds light on the potential strategies that could be envisaged to potentiate immune-mediated tumor control in cancer patients.
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