1
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Fettig NM, Pu A, Osborne LC, Gommerman JL. The influence of aging and the microbiome in multiple sclerosis and other neurologic diseases. Immunol Rev 2024. [PMID: 38890777 DOI: 10.1111/imr.13361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The human gut microbiome is well-recognized as a key player in maintaining health. However, it is a dynamic entity that changes across the lifespan. How the microbial changes that occur in later decades of life shape host health or impact age-associated inflammatory neurological diseases such as multiple sclerosis (MS) is still unclear. Current understanding of the aging gut microbiome is largely limited to cross-sectional observational studies. Moreover, studies in humans are limited by confounding host-intrinsic and extrinsic factors that are not easily disentangled from aging. This review provides a comprehensive summary of existing literature on the aging gut microbiome and its known relationships with neurological diseases, with a specific focus on MS. We will also discuss preclinical animal models and human studies that shed light on the complex microbiota-host interactions that have the potential to influence disease pathology and progression in aging individuals. Lastly, we propose potential avenues of investigation to deconvolute features of an aging microbiota that contribute to disease, or alternatively promote health in advanced age.
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Affiliation(s)
- Naomi M Fettig
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Annie Pu
- Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Lisa C Osborne
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
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2
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Strohm AO, Majewska AK. Physical exercise regulates microglia in health and disease. Front Neurosci 2024; 18:1420322. [PMID: 38911597 PMCID: PMC11192042 DOI: 10.3389/fnins.2024.1420322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 05/20/2024] [Indexed: 06/25/2024] Open
Abstract
There is a well-established link between physical activity and brain health. As such, the effectiveness of physical exercise as a therapeutic strategy has been explored in a variety of neurological contexts. To determine the extent to which physical exercise could be most beneficial under different circumstances, studies are needed to uncover the underlying mechanisms behind the benefits of physical activity. Interest has grown in understanding how physical activity can regulate microglia, the resident immune cells of the central nervous system. Microglia are key mediators of neuroinflammatory processes and play a role in maintaining brain homeostasis in healthy and pathological settings. Here, we explore the evidence suggesting that physical activity has the potential to regulate microglia activity in various animal models. We emphasize key areas where future research could contribute to uncovering the therapeutic benefits of engaging in physical exercise.
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Affiliation(s)
- Alexandra O. Strohm
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - Ania K. Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, United States
- Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, United States
- Center for Visual Science, University of Rochester Medical Center, Rochester, NY, United States
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3
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Sanabria-Castro A, Alape-Girón A, Flores-Díaz M, Echeverri-McCandless A, Parajeles-Vindas A. Oxidative stress involvement in the molecular pathogenesis and progression of multiple sclerosis: a literature review. Rev Neurosci 2024; 35:355-371. [PMID: 38163257 DOI: 10.1515/revneuro-2023-0091] [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: 08/16/2023] [Accepted: 11/26/2023] [Indexed: 01/03/2024]
Abstract
Multiple sclerosis (MS) is an autoimmune debilitating disease of the central nervous system caused by a mosaic of interactions between genetic predisposition and environmental factors. The pathological hallmarks of MS are chronic inflammation, demyelination, and neurodegeneration. Oxidative stress, a state of imbalance between the production of reactive species and antioxidant defense mechanisms, is considered one of the key contributors in the pathophysiology of MS. This review is a comprehensive overview of the cellular and molecular mechanisms by which oxidant species contribute to the initiation and progression of MS including mitochondrial dysfunction, disruption of various signaling pathways, and autoimmune response activation. The detrimental effects of oxidative stress on neurons, oligodendrocytes, and astrocytes, as well as the role of oxidants in promoting and perpetuating inflammation, demyelination, and axonal damage, are discussed. Finally, this review also points out the therapeutic potential of various synthetic antioxidants that must be evaluated in clinical trials in patients with MS.
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Affiliation(s)
- Alfredo Sanabria-Castro
- Unidad de Investigación, Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José, 10103, Costa Rica
- Departamento de Farmacología, Toxicología y Farmacodependencia, Facultad de Farmacia, Universidad de Costa Rica, San Pedro de Montes de Oca, 11501, Costa Rica
| | - Alberto Alape-Girón
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, Dulce Nombre Vázquez de Coronado, 11103, Costa Rica
| | - Marietta Flores-Díaz
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, Dulce Nombre Vázquez de Coronado, 11103, Costa Rica
| | - Ann Echeverri-McCandless
- Unidad de Investigación, Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José, 10103, Costa Rica
| | - Alexander Parajeles-Vindas
- Servicio de Neurología, Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José, 10103, Costa Rica
- Servicio de Neurología, Hospital Clínica Bíblica, San José, 10104, Costa Rica
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4
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Strohm AO, Johnston C, Hernady E, Marples B, O'Banion MK, Majewska AK. Cranial irradiation disrupts homeostatic microglial dynamic behavior. J Neuroinflammation 2024; 21:82. [PMID: 38570852 PMCID: PMC10993621 DOI: 10.1186/s12974-024-03073-z] [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: 12/18/2023] [Accepted: 03/22/2024] [Indexed: 04/05/2024] Open
Abstract
Cranial irradiation causes cognitive deficits that are in part mediated by microglia, the resident immune cells of the brain. Microglia are highly reactive, exhibiting changes in shape and morphology depending on the function they are performing. Additionally, microglia processes make dynamic, physical contacts with different components of their environment to monitor the functional state of the brain and promote plasticity. Though evidence suggests radiation perturbs homeostatic microglia functions, it is unknown how cranial irradiation impacts the dynamic behavior of microglia over time. Here, we paired in vivo two-photon microscopy with a transgenic mouse model that labels cortical microglia to follow these cells and determine how they change over time in cranial irradiated mice and their control littermates. We show that a single dose of 10 Gy cranial irradiation disrupts homeostatic cortical microglia dynamics during a 1-month time course. We found a lasting loss of microglial cells following cranial irradiation, coupled with a modest dysregulation of microglial soma displacement at earlier timepoints. The homogeneous distribution of microglia was maintained, suggesting microglia rearrange themselves to account for cell loss and maintain territorial organization following cranial irradiation. Furthermore, we found cranial irradiation reduced microglia coverage of the parenchyma and their surveillance capacity, without overtly changing morphology. Our results demonstrate that a single dose of radiation can induce changes in microglial behavior and function that could influence neurological health. These results set the foundation for future work examining how cranial irradiation impacts complex cellular dynamics in the brain which could contribute to the manifestation of cognitive deficits.
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Affiliation(s)
- Alexandra O Strohm
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Carl Johnston
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Eric Hernady
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Brian Marples
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - M Kerry O'Banion
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, 14642, USA
- Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, 14642, USA.
- Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, 14642, USA.
- Center for Visual Science, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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5
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Wang L, Hong W, Zhu H, He Q, Yang B, Wang J, Weng Q. Macrophage senescence in health and diseases. Acta Pharm Sin B 2024; 14:1508-1524. [PMID: 38572110 PMCID: PMC10985037 DOI: 10.1016/j.apsb.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 10/16/2023] [Accepted: 12/06/2023] [Indexed: 04/05/2024] Open
Abstract
Macrophage senescence, manifested by the special form of durable cell cycle arrest and chronic low-grade inflammation like senescence-associated secretory phenotype, has long been considered harmful. Persistent senescence of macrophages may lead to maladaptation, immune dysfunction, and finally the development of age-related diseases, infections, autoimmune diseases, and malignancies. However, it is a ubiquitous, multi-factorial, and dynamic complex phenomenon that also plays roles in remodeled processes, including wound repair and embryogenesis. In this review, we summarize some general molecular changes and several specific biomarkers during macrophage senescence, which may bring new sight to recognize senescent macrophages in different conditions. Also, we take an in-depth look at the functional changes in senescent macrophages, including metabolism, autophagy, polarization, phagocytosis, antigen presentation, and infiltration or recruitment. Furthermore, some degenerations and diseases associated with senescent macrophages as well as the mechanisms or relevant genetic regulations of senescent macrophages are integrated, not only emphasizing the possibility of regulating macrophage senescence to benefit age-associated diseases but also has an implication on the finding of potential targets or drugs clinically.
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Affiliation(s)
- Longling Wang
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Nanhu Brain-Computer Interface Institute, Hangzhou 311100, China
| | - Wenxiang Hong
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hong Zhu
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qiaojun He
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Nanhu Brain-Computer Interface Institute, Hangzhou 311100, China
| | - Bo Yang
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiajia Wang
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Nanhu Brain-Computer Interface Institute, Hangzhou 311100, China
- Taizhou Institute of Zhejiang University, Taizhou 318000, China
| | - Qinjie Weng
- Center for Drug Safety Evaluation and Research, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Nanhu Brain-Computer Interface Institute, Hangzhou 311100, China
- Taizhou Institute of Zhejiang University, Taizhou 318000, China
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
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6
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Charoensaensuk V, Huang BR, Huang ST, Lin C, Xie SY, Chen CW, Chen YC, Cheng HT, Liu YS, Lai SW, Shen CK, Lin HJ, Yang LY, Lu DY. LPS priming-induced immune tolerance mitigates LPS-stimulated microglial activation and social avoidance behaviors in mice. J Pharmacol Sci 2024; 154:225-235. [PMID: 38485340 DOI: 10.1016/j.jphs.2024.02.006] [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: 11/13/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 03/19/2024] Open
Abstract
In this study, we investigated the regulatory mechanisms underlying the effects of LPS tolerance on the inflammatory homeostasis of immune cells. LPS priming-induced immune tolerance downregulated cyclooxygenase-2, and lowered the production of prostaglandin-E2 in microglial cells. In addition, LPS tolerance downregulated the expression of suppressor of cytokine signaling 3, and inducible nitric oxide synthase/nitric oxide; suppressed the LPS-mediated induction of tumor necrosis factor-α, interleukin (IL)-6, and IL-1; and reduced reactive oxygen species production in microglial cells. LPS stimulation increased the levels of the adaptive response-related proteins heme oxygenase-1 and superoxide dismutase 2, and the levels of heme oxygenase-1 (HO-1) enhanced after LPS priming. Systemic administration of low-dose LPS (0.5 mg/kg) to mice for 4 consecutive days attenuated high-dose LPS (5 mg/kg)-induced inflammatory response, microglial activation, and proinflammatory cytokine expression. Moreover, repeated exposure to low-dose LPS suppressed the recruitment of peripheral monocytes or macrophages to brain regions and downregulated the expression of proinflammatory cytokines. Notably, LPS-induced social avoidance behaviors in mice were mitigated by immune tolerance. In conclusion, immune tolerance may reduce proinflammatory cytokine expression and reactive oxygen species production. Our findings provide insights into the effects of endotoxin tolerance on innate immune cells and social behaviors.
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Affiliation(s)
- Vichuda Charoensaensuk
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Bor-Ren Huang
- Department of Neurosurgery, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan; School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Sian-Ting Huang
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Chingju Lin
- Department of Physiology, School of Medicine, China Medical University, Taichung, 404328, Taiwan
| | - Sheng-Yun Xie
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Chao-Wei Chen
- Institute of New Drug Development, China Medical University, Taichung, Taiwan
| | - Yen-Chang Chen
- Institute of New Drug Development, China Medical University, Taichung, Taiwan
| | - Han-Tsung Cheng
- Department of Surgery, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Shu Liu
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Sheng-Wei Lai
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Ching-Kai Shen
- Graduate Institute of Biomedical Science, China Medical University, Taichung, Taiwan
| | - Hui-Jung Lin
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Liang-Yo Yang
- Department of Physiology, School of Medicine, China Medical University, Taichung, 404328, Taiwan; Laboratory for Neural Repair, China Medical University Hospital, Taichung, 404327, Taiwan; Biomedical Technology R&D Center, China Medical University Hospital, Taichung, 404327, Taiwan.
| | - Dah-Yuu Lu
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan; Department of Photonics and Communication Engineering, Asia University, Taichung, Taiwan.
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7
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Sepulveda J, Kim JY, Binder J, Vicini S, Rebeck GW. APOE4 genotype and aging impair injury-induced microglial behavior in brain slices, including toward Aβ, through P2RY12. Mol Neurodegener 2024; 19:24. [PMID: 38468308 DOI: 10.1186/s13024-024-00714-y] [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: 09/19/2023] [Accepted: 02/22/2024] [Indexed: 03/13/2024] Open
Abstract
Microglia are highly dynamic cells that play a critical role in tissue homeostasis through the surveillance of brain parenchyma and response to cues associated with damage. Aging and APOE4 genotype are the strongest risk factors for Alzheimer's disease (AD), but how they affect microglial dynamics remains unclear. Using ex vivo confocal microscopy, we analyzed microglial dynamic behaviors in the entorhinal cortex (EC) and hippocampus CA1 of 6-, 12-, and 21-month-old mice APOE3 or APOE4 knock-in mice expressing GFP under the CX3CR1 promoter. To study microglia surveillance, we imaged microglia baseline motility for 20 min and measured the extension and retraction of processes. We found that APOE4 microglia exhibited significantly less brain surveillance (27%) compared to APOE3 microglia in 6-month-old mice; aging exacerbated this deficit. To measure microglia response to damage, we imaged process motility in response to ATP, an injury-associated signal, for 30 min. We found APOE4 microglia extended their processes significantly slower (0.9 µm/min, p < 0.005) than APOE3 microglia (1.1 μm/min) in 6-month-old animals. APOE-associated alterations in microglia motility were observed in 12- and 21-month-old animals, and this effect was exacerbated with aging in APOE4 microglia. We measured protein and mRNA levels of P2RY12, a core microglial receptor required for process movement in response to damage. We found that APOE4 microglia express significantly less P2RY12 receptors compared to APOE3 microglia despite no changes in P2RY12 transcripts. To examine if the effect of APOE4 on the microglial response to ATP also applied to amyloid β (Aβ), we infused locally Hi-Lyte Fluor 555-labeled Aβ in acute brain slices of 6-month-old mice and imaged microglia movement for 2 h. APOE4 microglia showed a significantly slower (p < 0.0001) process movement toward the Aβ, and less Aβ coverage at early time points after Aβ injection. To test whether P2RY12 is involved in process movement in response to Aβ, we treated acute brain slices with a P2RY12 antagonist before Aβ injection; microglial processes no longer migrated towards Aβ. These results provide mechanistic insights into the impact of APOE4 genotype and aging in dynamic microglial behaviors prior to gross Aβ pathology and could help explain how APOE4 brains are more susceptible to AD pathogenesis.
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Affiliation(s)
- Jordy Sepulveda
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, 20007, USA
| | - Jennifer Yejean Kim
- Department of Neuroscience, Georgetown University, Washington, DC, 20007, USA
| | - Joseph Binder
- Department of Neuroscience, Georgetown University, Washington, DC, 20007, USA
| | - Stefano Vicini
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, 20007, USA
| | - G William Rebeck
- Department of Neuroscience, Georgetown University, Washington, DC, 20007, USA.
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Li Z, Wu J, Zhao T, Wei Y, Xu Y, Liu Z, Li X, Chen X. Microglial activation in spaceflight and microgravity: potential risk of cognitive dysfunction and poor neural health. Front Cell Neurosci 2024; 18:1296205. [PMID: 38425432 PMCID: PMC10902453 DOI: 10.3389/fncel.2024.1296205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
Due to the increased crewed spaceflights in recent years, it is vital to understand how the space environment affects human health. A lack of gravitational force is known to risk multiple physiological functions of astronauts, particularly damage to the central nervous system (CNS). As innate immune cells of the CNS, microglia can transition from a quiescent state to a pathological state, releasing pro-inflammatory cytokines that contribute to neuroinflammation. There are reports indicating that microglia can be activated by simulating microgravity or exposure to galactic cosmic rays (GCR). Consequently, microglia may play a role in the development of neuroinflammation during spaceflight. Prolonged spaceflight sessions raise concerns about the chronic activation of microglia, which could give rise to various neurological disorders, posing concealed risks to the neural health of astronauts. This review summarizes the risks associated with neural health owing to microglial activation and explores the stressors that trigger microglial activation in the space environment. These stressors include GCR, microgravity, and exposure to isolation and stress. Of particular focus is the activation of microglia under microgravity conditions, along with the proposal of a potential mechanism.
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Affiliation(s)
- Zihan Li
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Jiarui Wu
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Tianyuan Zhao
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Yiyun Wei
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Yajing Xu
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Zongjian Liu
- Department of Rehabilitation, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Xiaoqiong Li
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Xuechai Chen
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
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9
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Olmedillas M, Brawek B, Li K, Richter C, Garaschuk O. Plaque vicinity as a hotspot of microglial turnover in a mouse model of Alzheimer's disease. Glia 2023; 71:2884-2901. [PMID: 37596829 DOI: 10.1002/glia.24458] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/25/2023] [Accepted: 08/04/2023] [Indexed: 08/20/2023]
Abstract
Microglia, the major immune cells of the brain, are functionally heterogeneous but in vivo functional properties of these cells are rarely studied at single-cell resolution. By using microRNA-9 regulated viral vectors for multicolor labeling and longitudinal in vivo monitoring of individual microglia, we followed their fate in the cortex of healthy adult mice and at the onset of amyloidosis in a mouse model of Alzheimer's disease. In wild-type mice, microglia were rather mobile (16% of the cells migrated at least once in 10-20 days) but had a low turnover as documented by low division and death rates. Half of the migratory events were tightly associated with blood vessels. Surprisingly, basic migration properties of microglia (i.e., fraction of migrating cells, saltatory migration pattern, speed of migration, translocation distance, and strong association with blood vessels) were preserved in amyloid-depositing brains, despite amyloid plaques becoming the major destination of migration. Besides, amyloid deposition significantly increased microglial division and death rates. Moreover, the plaque vicinity became a hotspot of microglial turnover, harboring 33% of all migration, 70% of death and 54% of division events.
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Affiliation(s)
- Maria Olmedillas
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Kaizhen Li
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Cris Richter
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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10
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Boylan MA, Pincetic A, Romano G, Tatton N, Kenkare-Mitra S, Rosenthal A. Targeting Progranulin as an Immuno-Neurology Therapeutic Approach. Int J Mol Sci 2023; 24:15946. [PMID: 37958929 PMCID: PMC10647331 DOI: 10.3390/ijms242115946] [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: 09/19/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
Immuno-neurology is an emerging therapeutic strategy for dementia and neurodegeneration designed to address immune surveillance failure in the brain. Microglia, as central nervous system (CNS)-resident myeloid cells, routinely perform surveillance of the brain and support neuronal function. Loss-of-function (LOF) mutations causing decreased levels of progranulin (PGRN), an immune regulatory protein, lead to dysfunctional microglia and are associated with multiple neurodegenerative diseases, including frontotemporal dementia caused by the progranulin gene (GRN) mutation (FTD-GRN), Alzheimer's disease (AD), Parkinson's disease (PD), limbic-predominant age-related transactivation response deoxyribonucleic acid binding protein 43 (TDP-43) encephalopathy (LATE), and amyotrophic lateral sclerosis (ALS). Immuno-neurology targets immune checkpoint-like proteins, offering the potential to convert aging and dysfunctional microglia into disease-fighting cells that counteract multiple disease pathologies, clear misfolded proteins and debris, promote myelin and synapse repair, optimize neuronal function, support astrocytes and oligodendrocytes, and maintain brain vasculature. Several clinical trials are underway to elevate PGRN levels as one strategy to modulate the function of microglia and counteract neurodegenerative changes associated with various disease states. If successful, these and other immuno-neurology drugs have the potential to revolutionize the treatment of neurodegenerative disorders by harnessing the brain's immune system and shifting it from an inflammatory/pathological state to an enhanced physiological/homeostatic state.
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Affiliation(s)
| | | | | | | | | | - Arnon Rosenthal
- Alector, Inc., 131 Oyster Point Blvd, Suite 600, South San Francisco, CA 94080, USA
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11
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Miao J, Chen L, Pan X, Li L, Zhao B, Lan J. Microglial Metabolic Reprogramming: Emerging Insights and Therapeutic Strategies in Neurodegenerative Diseases. Cell Mol Neurobiol 2023; 43:3191-3210. [PMID: 37341833 DOI: 10.1007/s10571-023-01376-y] [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: 05/01/2023] [Accepted: 06/14/2023] [Indexed: 06/22/2023]
Abstract
Microglia, the resident immune cells of the central nervous system, play a critical role in maintaining brain homeostasis. However, in neurodegenerative conditions, microglial cells undergo metabolic reprogramming in response to pathological stimuli, including Aβ plaques, Tau tangles, and α-synuclein aggregates. This metabolic shift is characterized by a transition from oxidative phosphorylation (OXPHOS) to glycolysis, increased glucose uptake, enhanced production of lactate, lipids, and succinate, and upregulation of glycolytic enzymes. These metabolic adaptations result in altered microglial functions, such as amplified inflammatory responses and diminished phagocytic capacity, which exacerbate neurodegeneration. This review highlights recent advances in understanding the molecular mechanisms underlying microglial metabolic reprogramming in neurodegenerative diseases and discusses potential therapeutic strategies targeting microglial metabolism to mitigate neuroinflammation and promote brain health. Microglial Metabolic Reprogramming in Neurodegenerative Diseases This graphical abstract illustrates the metabolic shift in microglial cells in response to pathological stimuli and highlights potential therapeutic strategies targeting microglial metabolism for improved brain health.
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Affiliation(s)
- Jifei Miao
- Shenzhen Bao'an Traditional Chinese Medicine Hospital, Shenzhen, China
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Lihua Chen
- Shenzhen Bao'an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Xiaojin Pan
- Shenzhen Bao'an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Liqing Li
- Shenzhen Bao'an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Beibei Zhao
- Shenzhen Bao'an Traditional Chinese Medicine Hospital, Shenzhen, China.
| | - Jiao Lan
- Shenzhen Bao'an Traditional Chinese Medicine Hospital, Shenzhen, China.
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12
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Jiménez Peinado P, Urbach A. From Youthful Vigor to Aging Decline: Unravelling the Intrinsic and Extrinsic Determinants of Hippocampal Neural Stem Cell Aging. Cells 2023; 12:2086. [PMID: 37626896 PMCID: PMC10453598 DOI: 10.3390/cells12162086] [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: 06/22/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Since Joseph Altman published his pioneering work demonstrating neurogenesis in the hippocampus of adult rats, the number of publications in this field increased exponentially. Today, we know that the adult hippocampus harbors a pool of adult neural stem cells (NSCs) that are the source of life-long neurogenesis and plasticity. The functions of these NSCs are regulated by extrinsic cues arising from neighboring cells and the systemic environment. However, this tight regulation is subject to imbalance with age, resulting in a decline in adult NSCs and neurogenesis, which contributes to the progressive deterioration of hippocampus-related cognitive functions. Despite extensive investigation, the mechanisms underlying this age-related decline in neurogenesis are only incompletely understood, but appear to include an increase in NSC quiescence, changes in differentiation patterns, and NSC exhaustion. In this review, we summarize recent work that has improved our knowledge of hippocampal NSC aging, focusing on NSC-intrinsic mechanisms as well as cellular and molecular changes in the niche and systemic environment that might be involved in the age-related decline in NSC functions. Additionally, we identify future directions that may advance our understanding of NSC aging and the concomitant loss of hippocampal neurogenesis and plasticity.
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Affiliation(s)
| | - Anja Urbach
- Department of Neurology, Jena University Hospital, 07747 Jena, Germany
- Jena Center for Healthy Aging, Jena University Hospital, 07747 Jena, Germany
- Aging Research Center Jena, Leibniz Institute on Aging, 07745 Jena, Germany
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13
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Latham AS, Moreno JA, Geer CE. Biological agents and the aging brain: glial inflammation and neurotoxic signaling. FRONTIERS IN AGING 2023; 4:1244149. [PMID: 37649972 PMCID: PMC10464498 DOI: 10.3389/fragi.2023.1244149] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/01/2023] [Indexed: 09/01/2023]
Abstract
Neuroinflammation is a universal characteristic of brain aging and neurological disorders, irrespective of the disease state. Glial inflammation mediates this signaling, through astrocyte and microglial polarization from neuroprotective to neurotoxic phenotypes. Glial reactivity results in the loss of homeostasis, as these cells no longer provide support to neurons, in addition to the production of chronically toxic pro-inflammatory mediators. These glial changes initiate an inflammatory brain state that injures the central nervous system (CNS) over time. As the brain ages, glia are altered, including increased glial cell numbers, morphological changes, and either a pre-disposition or inability to become reactive. These alterations induce age-related neuropathologies, ultimately leading to neuronal degradation and irreversible damage associated with disorders of the aged brain, including Alzheimer's Disease (AD) and other related diseases. While the complex interactions of these glial cells and the brain are well studied, the role additional stressors, such as infectious agents, play on age-related neuropathology has not been fully elucidated. Both biological agents in the periphery, such as bacterial infections, or in the CNS, including viral infections like SARS-CoV-2, push glia into neuroinflammatory phenotypes that can exacerbate pathology within the aging brain. These biological agents release pattern associated molecular patterns (PAMPs) that bind to pattern recognition receptors (PRRs) on glial cells, beginning an inflammatory cascade. In this review, we will summarize the evidence that biological agents induce reactive glia, which worsens age-related neuropathology.
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Affiliation(s)
- Amanda S. Latham
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
- Brain Research Center, Colorado State University, Fort Collins, CO, United States
| | - Julie A. Moreno
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
- Brain Research Center, Colorado State University, Fort Collins, CO, United States
| | - Charlize E. Geer
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
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14
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Jin K, Yao Z, van Velthoven CTJ, Kaplan ES, Glattfelder K, Barlow ST, Boyer G, Carey D, Casper T, Chakka AB, Chakrabarty R, Clark M, Departee M, Desierto M, Gary A, Gloe J, Goldy J, Guilford N, Guzman J, Hirschstein D, Lee C, Liang E, Pham T, Reding M, Ronellenfitch K, Ruiz A, Sevigny J, Shapovalova N, Shulga L, Sulc J, Torkelson A, Tung H, Levi B, Sunkin SM, Dee N, Esposito L, Smith K, Tasic B, Zeng H. Cell-type specific molecular signatures of aging revealed in a brain-wide transcriptomic cell-type atlas. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.550355. [PMID: 38168182 PMCID: PMC10760145 DOI: 10.1101/2023.07.26.550355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Biological aging can be defined as a gradual loss of homeostasis across various aspects of molecular and cellular function. Aging is a complex and dynamic process which influences distinct cell types in a myriad of ways. The cellular architecture of the mammalian brain is heterogeneous and diverse, making it challenging to identify precise areas and cell types of the brain that are more susceptible to aging than others. Here, we present a high-resolution single-cell RNA sequencing dataset containing ~1.2 million high-quality single-cell transcriptomic profiles of brain cells from young adult and aged mice across both sexes, including areas spanning the forebrain, midbrain, and hindbrain. We find age-associated gene expression signatures across nearly all 130+ neuronal and non-neuronal cell subclasses we identified. We detect the greatest gene expression changes in non-neuronal cell types, suggesting that different cell types in the brain vary in their susceptibility to aging. We identify specific, age-enriched clusters within specific glial, vascular, and immune cell types from both cortical and subcortical regions of the brain, and specific gene expression changes associated with cell senescence, inflammation, decrease in new myelination, and decreased vasculature integrity. We also identify genes with expression changes across multiple cell subclasses, pointing to certain mechanisms of aging that may occur across wide regions or broad cell types of the brain. Finally, we discover the greatest gene expression changes in cell types localized to the third ventricle of the hypothalamus, including tanycytes, ependymal cells, and Tbx3+ neurons found in the arcuate nucleus that are part of the neuronal circuits regulating food intake and energy homeostasis. These findings suggest that the area surrounding the third ventricle in the hypothalamus may be a hub for aging in the mouse brain. Overall, we reveal a dynamic landscape of cell-type-specific transcriptomic changes in the brain associated with normal aging that will serve as a foundation for the investigation of functional changes in the aging process and the interaction of aging and diseases.
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Affiliation(s)
- Kelly Jin
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | | | - Daniel Carey
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | - Max Departee
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Amanda Gary
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Jessica Gloe
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Jeff Goldy
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | - Changkyu Lee
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | | | - Josh Sevigny
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | - Josef Sulc
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Herman Tung
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Boaz Levi
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Nick Dee
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA
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15
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Mirarchi A, Albi E, Beccari T, Arcuri C. Microglia and Brain Disorders: The Role of Vitamin D and Its Receptor. Int J Mol Sci 2023; 24:11892. [PMID: 37569267 PMCID: PMC10419106 DOI: 10.3390/ijms241511892] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
Accounting for 5-20% of the total glial cells present in the adult brain, microglia are involved in several functions: maintenance of the neural environment, response to injury and repair, immunesurveillance, cytokine secretion, regulation of phagocytosis, synaptic pruning, and sculpting postnatal neural circuits. Microglia contribute to some neurodevelopmental disorders, such as Nasu-Hakola disease (NHD), Tourette syndrome (TS), autism spectrum disorder (ASD), and schizophrenia. Moreover, microglial involvement in neurodegenerative diseases, such as Alzheimer's (AD) and Parkinson's (PD) diseases, has also been well established. During the last two decades, epidemiological and research studies have demonstrated the involvement of vitamin D3 (VD3) in the brain's pathophysiology. VD3 is a fat-soluble metabolite that is required for the proper regulation of many of the body's systems, as well as for normal human growth and development, and shows neurotrophic and neuroprotective actions and influences on neurotransmission and synaptic plasticity, playing a role in various neurological diseases. In order to better understand the exact mechanisms behind the diverse actions of VD3 in the brain, a large number of studies have been performed on isolated cells or tissues of the central nervous system (CNS). Here, we discuss the involvement of VD3 and microglia on neurodegeneration- and aging-related diseases.
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Affiliation(s)
- Alessandra Mirarchi
- Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy;
| | - Elisabetta Albi
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy; (E.A.); (T.B.)
| | - Tommaso Beccari
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy; (E.A.); (T.B.)
| | - Cataldo Arcuri
- Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy;
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16
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Boghozian R, Sharma S, Narayana K, Cheema M, Brown CE. Sex and interferon gamma signaling regulate microglia migration in the adult mouse cortex in vivo. Proc Natl Acad Sci U S A 2023; 120:e2302892120. [PMID: 37428916 PMCID: PMC10629543 DOI: 10.1073/pnas.2302892120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 06/02/2023] [Indexed: 07/12/2023] Open
Abstract
Although microglia possess the unique ability to migrate, whether mobility is evident in all microglia, is sex dependent, and what molecular mechanisms drive this, is not well understood in the adult brain. Using longitudinal in vivo two-photon imaging of sparsely labeled microglia, we find a relatively small population of microglia (~5%) are mobile under normal conditions. Following injury (microbleed), the fraction of mobile microglia increased in a sex-dependent manner, with male microglia migrating significantly greater distances toward the microbleed relative to their female counterparts. To understand the signaling pathways involved, we interrogated the role of interferon gamma (IFNγ). Our data show that in male mice, stimulating microglia with IFNγ promotes migration whereas inhibiting IFNγ receptor 1 signaling inhibits them. By contrast, female microglia were generally unaffected by these manipulations. These findings highlight the diversity of microglia migratory responses to injury, its dependence on sex and the signaling mechanisms that modulate this behavior.
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Affiliation(s)
- Roobina Boghozian
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Sorabh Sharma
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Kamal Narayana
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Manjinder Cheema
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Craig E. Brown
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, BCV6T 2A1, Canada
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17
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Kushwah N, Bora K, Maurya M, Pavlovich MC, Chen J. Oxidative Stress and Antioxidants in Age-Related Macular Degeneration. Antioxidants (Basel) 2023; 12:1379. [PMID: 37507918 PMCID: PMC10376043 DOI: 10.3390/antiox12071379] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
Oxidative stress plays a crucial role in aging-related eye diseases, including age-related macular degeneration (AMD), cataracts, and glaucoma. With age, antioxidant reparative capacity decreases, and excess levels of reactive oxygen species produce oxidative damage in many ocular cell types underling age-related pathologies. In AMD, loss of central vision in the elderly is caused primarily by retinal pigment epithelium (RPE) dysfunction and degeneration and/or choroidal neovascularization that trigger malfunction and loss of photo-sensing photoreceptor cells. Along with various genetic and environmental factors that contribute to AMD, aging and age-related oxidative damage have critical involvement in AMD pathogenesis. To this end, dietary intake of antioxidants is a proven way to scavenge free radicals and to prevent or slow AMD progression. This review focuses on AMD and highlights the pathogenic role of oxidative stress in AMD from both clinical and experimental studies. The beneficial roles of antioxidants and dietary micronutrients in AMD are also summarized.
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Affiliation(s)
| | | | | | | | - Jing Chen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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18
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Xue S, Lozinski BM, Ghorbani S, Ta K, D'Mello C, Yong VW, Dong Y. Elevated Galectin-3 Is Associated with Aging, Multiple Sclerosis, and Oxidized Phosphatidylcholine-Induced Neurodegeneration. J Neurosci 2023; 43:4725-4737. [PMID: 37208177 PMCID: PMC10286945 DOI: 10.1523/jneurosci.2312-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/25/2023] [Accepted: 05/05/2023] [Indexed: 05/21/2023] Open
Abstract
Aging is a significant risk factor associated with the progression of CNS neurodegenerative diseases including multiple sclerosis (MS). Microglia, the resident macrophages of the CNS parenchyma, are a major population of immune cells that accumulate in MS lesions. While they normally regulate tissue homeostasis and facilitate the clearance of neurotoxic molecules including oxidized phosphatidylcholines (OxPCs), their transcriptome and neuroprotective functions are reprogrammed by aging. Thus, determining the factors that instigate aging associated microglia dysfunction can lead to new insights for promoting CNS repair and for halting MS disease progression. Through single-cell RNA sequencing (scRNAseq), we identified Lgals3, which encodes for galectin-3 (Gal3), as an age upregulated gene by microglia responding to OxPC. Consistently, excess Gal3 accumulated in OxPC and lysolecithin-induced focal spinal cord white matter (SCWM) lesions of middle-aged mice compared with young mice. Gal3 was also elevated in mouse experimental autoimmune encephalomyelitis (EAE) lesions and more importantly in MS brain lesions from two male and one female individuals. While Gal3 delivery alone into the mouse spinal cord did not induce damage, its co-delivery with OxPC increased cleaved caspase 3 and IL-1β within white matter lesions and exacerbated OxPC-induced injury. Conversely, OxPC-mediated neurodegeneration was reduced in Gal3-/- mice compared with Gal3+/+ mice. Thus, Gal3 is associated with increased neuroinflammation and neurodegeneration and its overexpression by microglia/macrophages may be detrimental for lesions within the aging CNS.SIGNIFICANCE STATEMENT Aging accelerates the progression of neurodegenerative diseases such as multiple sclerosis (MS). Understanding the molecular mechanisms of aging that increases the susceptibility of the CNS to damage could lead to new strategies to manage MS progression. Here, we highlight that microglia/macrophage-associated galectin-3 (Gal3) was upregulated with age exacerbated neurodegeneration in the mouse spinal cord white matter (SCWM) and in MS lesions. More importantly, co-injection of Gal3 with oxidized phosphatidylcholines (OxPCs), which are neurotoxic lipids found in MS lesions, caused greater neurodegeneration compared with injection of OxPC alone, whereas genetic loss of Gal3 reduced OxPC damage. These results demonstrate that Gal3 overexpression is detrimental to CNS lesions and suggest its deposition in MS lesions may contribute to neurodegeneration.
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Affiliation(s)
- Sara Xue
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Brian M Lozinski
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Samira Ghorbani
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Khanh Ta
- Department of Biochemistry, Microbiology, and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Charlotte D'Mello
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - V Wee Yong
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yifei Dong
- Department of Biochemistry, Microbiology, and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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19
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Britton R, Wasley T, Harish R, Holz C, Hall J, Yee DC, Melton Witt J, Booth EA, Braithwaite S, Czirr E, Kerrisk Campbell M. Noncanonical Activity of Tissue Inhibitor of Metalloproteinases 2 (TIMP2) Improves Cognition and Synapse Density in Aging. eNeuro 2023; 10:ENEURO.0031-23.2023. [PMID: 37321845 DOI: 10.1523/eneuro.0031-23.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/01/2023] [Accepted: 05/14/2023] [Indexed: 06/17/2023] Open
Abstract
Peripheral administration of tissue inhibitor of metalloproteinases 2 (TIMP2), a protein inhibitor of matrix metalloproteinases (MMPs), has previously been shown to have beneficial effects on cognition and neurons in aged mice. Here, to better understand the potential of recombinant TIMP2 proteins, an IgG4Fc fusion protein (TIMP2-hIgG4) was developed to extend the plasma half-life of TIMP2. Following one month of administration of TIMP2 or TIMP2-hIgG4 via intraperitoneal injections, 23-month-old male C57BL/6J mice showed improved hippocampal-dependent memory in a Y-maze, increased hippocampal cfos gene expression, and increased excitatory synapse density in the CA1 and dentate gyrus (DG) of the hippocampus. Thus, fusion to hIgG4 extended the half-life of TIMP2 while retaining the beneficial cognitive and neuronal effects. Moreover, it retained its ability to cross the blood-brain barrier. To deepen the mechanistic understanding of the beneficial function of TIMP2 on neuronal activity and cognition, a TIMP2 construct lacking MMP inhibitory activity, Ala-TIMP2, was generated, which provides steric hindrance that prevents inhibition of MMPs by the TIMP2 protein while still allowing MMP binding. A comprehensive assessment of the MMP inhibitory and binding capacity of these engineered proteins is outlined. Surprisingly, MMP inhibition by TIMP2 was not essential for its beneficial effects on cognition and neuronal function. These findings both confirm previously published research, expand on the potential mechanism for the beneficial effects of TIMP2, and provide important details for a therapeutic path forward for TIMP2 recombinant proteins in aging-related cognitive decline.
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Affiliation(s)
| | - Tristan Wasley
- Grifols Diagnostic Solutions, Inc., Emeryville, CA 94608
| | | | - Charles Holz
- Grifols Diagnostic Solutions, Inc., Emeryville, CA 94608
| | - John Hall
- Grifols Diagnostic Solutions, Inc., Emeryville, CA 94608
| | - Dennis C Yee
- Grifols Diagnostic Solutions, Inc., Emeryville, CA 94608
| | | | | | | | - Eva Czirr
- Alkahest, Inc., San Carlos, CA 94070
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20
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Lemaitre P, Tareen SHK, Pasciuto E, Mascali L, Martirosyan A, Callaerts‐Vegh Z, Poovathingal S, Dooley J, Holt MG, Yshii L, Liston A. Molecular and cognitive signatures of ageing partially restored through synthetic delivery of IL2 to the brain. EMBO Mol Med 2023; 15:e16805. [PMID: 36975362 PMCID: PMC10165365 DOI: 10.15252/emmm.202216805] [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: 08/28/2022] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/29/2023] Open
Abstract
Cognitive decline is a common pathological outcome during aging, with an ill-defined molecular and cellular basis. In recent years, the concept of inflammaging, defined as a low-grade inflammation increasing with age, has emerged. Infiltrating T cells accumulate in the brain with age and may contribute to the amplification of inflammatory cascades and disruptions to the neurogenic niche observed with age. Recently, a small resident population of regulatory T cells has been identified in the brain, and the capacity of IL2-mediated expansion of this population to counter neuroinflammatory disease has been demonstrated. Here, we test a brain-specific IL2 delivery system for the prevention of neurological decline in aging mice. We identify the molecular hallmarks of aging in the brain glial compartments and identify partial restoration of this signature through IL2 treatment. At a behavioral level, brain IL2 delivery prevented the age-induced defect in spatial learning, without improving the general decline in motor skill or arousal. These results identify immune modulation as a potential path to preserving cognitive function for healthy aging.
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Affiliation(s)
- Pierre Lemaitre
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | | | - Emanuela Pasciuto
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | - Loriana Mascali
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | - Araks Martirosyan
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of NeurosciencesKU LeuvenLeuvenBelgium
| | | | | | - James Dooley
- Immunology ProgrammeThe Babraham InstituteBabrahamUK
- Department of PathologyThe University of CambridgeCambridgeUK
| | - Matthew G Holt
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of NeurosciencesKU LeuvenLeuvenBelgium
- Instituto de Investigaçāo e Inovaçāo em Saúde (i3S)University of PortoPortoPortugal
| | - Lidia Yshii
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
- Department of NeurosciencesKU LeuvenLeuvenBelgium
| | - Adrian Liston
- VIB Center for Brain and Disease ResearchLeuvenBelgium
- Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
- Immunology ProgrammeThe Babraham InstituteBabrahamUK
- Department of PathologyThe University of CambridgeCambridgeUK
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21
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Suthard RL, Jellinger AL, Surets M, Shpokayte M, Pyo AY, Buzharsky MD, Senne RA, Dorst K, Leblanc H, Ramirez S. Chronic Gq activation of ventral hippocampal neurons and astrocytes differentially affects memory and behavior. Neurobiol Aging 2023; 125:9-31. [PMID: 36801699 DOI: 10.1016/j.neurobiolaging.2023.01.007] [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: 09/15/2022] [Revised: 12/20/2022] [Accepted: 01/13/2023] [Indexed: 02/01/2023]
Abstract
Network dysfunction is implicated in numerous diseases and psychiatric disorders, and the hippocampus serves as a common origin for these abnormalities. To test the hypothesis that chronic modulation of neurons and astrocytes induces impairments in cognition, we activated the hM3D(Gq) pathway in CaMKII+ neurons or GFAP+ astrocytes within the ventral hippocampus across 3, 6, and 9 months. CaMKII-hM3Dq activation impaired fear extinction at 3 months and acquisition at 9 months. Both CaMKII-hM3Dq manipulation and aging had differential effects on anxiety and social interaction. GFAP-hM3Dq activation impacted fear memory at 6 and 9 months. GFAP-hM3Dq activation impacted anxiety in the open field only at the earliest time point. CaMKII-hM3Dq activation modified the number of microglia, while GFAP-hM3Dq activation impacted microglial morphological characteristics, but neither affected these measures in astrocytes. Overall, our study elucidates how distinct cell types can modify behavior through network dysfunction, while adding a more direct role for glia in modulating behavior.
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Affiliation(s)
- Rebecca L Suthard
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA; Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | - Alexandra L Jellinger
- Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | - Michelle Surets
- Undergraduate Program in Neuroscience, Boston University, Boston, MA, USA
| | - Monika Shpokayte
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA; Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | - Angela Y Pyo
- Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | | | - Ryan A Senne
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA; Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | - Kaitlyn Dorst
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA; Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | - Heloise Leblanc
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA; Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA
| | - Steve Ramirez
- Department of Biomedical Engineering, Boston University, Boston, MA, USA; Department of Psychological and Brain Sciences, The Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, MA, USA.
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22
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Gallizioli M, Arbaizar-Rovirosa M, Brea D, Planas AM. Differences in the post-stroke innate immune response between young and old. Semin Immunopathol 2023:10.1007/s00281-023-00990-8. [PMID: 37045990 DOI: 10.1007/s00281-023-00990-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 03/29/2023] [Indexed: 04/14/2023]
Abstract
Aging is associated to progressive changes impairing fundamental cellular and tissue functions, and the relationships amongst them through the vascular and immune systems. Aging factors are key to understanding the pathophysiology of stroke since they increase its risk and worsen its functional outcome. Most currently recognised hallmarks of aging are also involved in the cerebral responses to stroke. Notably, age-associated chronic low-grade inflammation is related to innate immune responses highlighted by induction of type-I interferon. The interferon program is prominent in microglia where it interrelates cell damage, danger signals, and phagocytosis with immunometabolic disturbances and inflammation. Microglia engulfment of damaged myelin and cell debris may overwhelm the cellular capacity for waste removal inducing intracellular lipid accumulation. Acute inflammation and interferon-stimulated gene expression are also typical features of acute stroke, where danger signal recognition by microglia trigger immunometabolic alterations underscored by lipid droplet biogenesis. Aging reduces the capacity to control these responses causing increased and persistent inflammation, metabolic dysregulation, and impaired cellular waste disposal. In turn, chronic peripheral inflammation during aging induces immunosenescence further worsening stroke-induced immunodepression, thus increasing the risk of post-stroke infection. Aging also alters gut microbiota composition inducing dysbiosis. These changes are enhanced by age-related diseases, such as atherosclerosis and type-II diabetes, that further promote vascular aging, predispose to stroke, and exacerbate brain inflammation after stroke. Current advances in aging research suggest that some age-associated alterations may be reversed. Future work will unravel whether such evolving anti-aging research may enable designing strategies to improve stroke outcome in the elderly.
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Affiliation(s)
- Mattia Gallizioli
- Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), S Rosselló 161, planta 6, 08036, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Rosselló 153, 08036, Barcelona, Spain
| | - Maria Arbaizar-Rovirosa
- Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), S Rosselló 161, planta 6, 08036, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Rosselló 153, 08036, Barcelona, Spain
| | - David Brea
- Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), S Rosselló 161, planta 6, 08036, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Rosselló 153, 08036, Barcelona, Spain
| | - Anna M Planas
- Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), S Rosselló 161, planta 6, 08036, Barcelona, Spain.
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Rosselló 153, 08036, Barcelona, Spain.
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23
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Ocañas SR, Ansere VA, Kellogg CM, Isola JVV, Chucair-Elliott AJ, Freeman WM. Chromosomal and gonadal factors regulate microglial sex effects in the aging brain. Brain Res Bull 2023; 195:157-171. [PMID: 36804773 PMCID: PMC10810555 DOI: 10.1016/j.brainresbull.2023.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023]
Abstract
Biological sex contributes to phenotypic sex effects through genetic (sex chromosomal) and hormonal (gonadal) mechanisms. There are profound sex differences in the prevalence and progression of age-related brain diseases, including neurodegenerative diseases. Inflammation of neural tissue is one of the most consistent age-related phenotypes seen with healthy aging and disease. The pro-inflammatory environment of the aging brain has primarily been attributed to microglial reactivity and adoption of heterogeneous reactive states dependent upon intrinsic (i.e., sex) and extrinsic (i.e., age, disease state) factors. Here, we review sex effects in microglia across the lifespan, explore potential genetic and hormonal molecular mechanisms of microglial sex effects, and discuss currently available models and methods to study sex effects in the aging brain. Despite recent attention to this area, significant further research is needed to mechanistically understand the regulation of microglial sex effects across the lifespan, which may open new avenues for sex informed prevention and treatment strategies.
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Affiliation(s)
- Sarah R Ocañas
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Victor A Ansere
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Collyn M Kellogg
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jose V V Isola
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Ana J Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Willard M Freeman
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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24
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Abstract
Alzheimer's disease (AD) is a debilitating age-related neurodegenerative condition. Unbiased genetic studies have implicated a central role for microglia, the resident innate immune cells of the central nervous system, in AD pathogenesis. On-going efforts are clarifying the biology underlying these associations and the microglial pathways that are dysfunctional in AD. Several genetic risk factors converge to decrease the function of activating microglial receptors and increase the function of inhibitory receptors, resulting in a seemingly dampened microglial phenotype in AD. Moreover, many of these microglial proteins that are genetically associated with AD appear to interact and share pathways or regulatory mechanisms, presenting several points of convergence that may be strategic targets for therapeutic intervention. Here, we review some of these studies and their implications for microglial participation in AD pathogenesis.
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25
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Godeanu S, Clarke D, Stopper L, Deftu AF, Popa-Wagner A, Bălșeanu AT, Scheller A, Catalin B. Microglial morphology in the somatosensory cortex across lifespan. A quantitative study. Dev Dyn 2023. [PMID: 36883224 DOI: 10.1002/dvdy.582] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Microglia are long-lived cells that constantly monitor their microenvironment. To accomplish this task, they constantly change their morphology both in the short and long term under physiological conditions. This makes the process of quantifying physiological microglial morphology difficult. RESULTS By using a semi-manual and a semi-automatic method to assess fine changes in cortical microglia morphology, we were able to quantify microglia changes in number, surveillance and branch tree starting from the fifth postnatal day to 2 years of life. We were able to identify a fluctuating behavior of most analyzed parameters characterized by a rapid cellular maturation, followed by a long period of relative stable morphology during the adult life with a final convergence to an aged phenotype. Detailed cellular arborization analysis revealed age-induced differences in microglia morphology, with mean branch length and the number of terminal processes changing constantly over time. CONCLUSIONS Our study provides insight into microglia morphology changes across lifespan under physiological conditions. We were able to highlight, that due to the dynamic nature of microglia several morphological parameters are needed to establish the physiological state of these cells.
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Affiliation(s)
- Sanziana Godeanu
- Experimental Research Centre for Normal and Pathological Aging, University of Medicine and Pharmacy of Craiova, Craiova, Romania.,Department of Molecular Physiology, CIPMM (Center for Integrative Physiology and Molecular Medicine), Building 48, University of Saarland, Homburg, Germany
| | - Devin Clarke
- School of Psychology and Sussex Neuroscience, The University of Sussex, Falmer, Brighton, UK
| | - Laura Stopper
- Department of Molecular Physiology, CIPMM (Center for Integrative Physiology and Molecular Medicine), Building 48, University of Saarland, Homburg, Germany
| | - Alexandru-Florian Deftu
- Pain Center, Department of Anesthesiology, Lausanne University Hospital (CHUV), Lausanne, Switzerland.,Faculty of Biology and Medicine (FBM), University of Lausanne (UNIL), Lausanne, Switzerland
| | - Aurel Popa-Wagner
- Experimental Research Centre for Normal and Pathological Aging, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Adrian Tudor Bălșeanu
- Experimental Research Centre for Normal and Pathological Aging, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Anja Scheller
- Department of Molecular Physiology, CIPMM (Center for Integrative Physiology and Molecular Medicine), Building 48, University of Saarland, Homburg, Germany
| | - Bogdan Catalin
- Experimental Research Centre for Normal and Pathological Aging, University of Medicine and Pharmacy of Craiova, Craiova, Romania.,Department of Molecular Physiology, CIPMM (Center for Integrative Physiology and Molecular Medicine), Building 48, University of Saarland, Homburg, Germany
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26
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Ng PY, McNeely TL, Baker DJ. Untangling senescent and damage-associated microglia in the aging and diseased brain. FEBS J 2023; 290:1326-1339. [PMID: 34873840 PMCID: PMC9167891 DOI: 10.1111/febs.16315] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/16/2021] [Accepted: 12/06/2021] [Indexed: 01/10/2023]
Abstract
Microglial homeostasis has emerged as a critical mediator of health and disease in the central nervous system. In their neuroprotective role as the predominant immune cells of the brain, microglia surveil the microenvironment for debris and pathogens, while also promoting neurogenesis and performing maintenance on synapses. Chronological ageing, disease onset, or traumatic injury promotes irreparable damage or deregulated signaling to reinforce neurotoxic phenotypes in microglia. These insults may include cellular senescence, a stable growth arrest often accompanied by the production of a distinctive pro-inflammatory secretory phenotype, which may contribute to age- or disease-driven decline in neuronal health and cognition and is a potential novel therapeutic target. Despite this increased scrutiny, unanswered questions remain about what distinguishes senescent microglia and non-senescent microglia reacting to insults occurring in ageing, disease, and injury, and how central the development of senescence is in their pivot from guardian to assailant. To intelligently design future studies to untangle senescent microglia from other primed and reactionary states, specific criteria must be developed that define this population and allow for comparisons between different model systems. Comparing microglial activity seen in homeostasis, ageing, disease, and injury allows for a more coherent understanding of when and how senescent and other harmful microglial subpopulations should be targeted.
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Affiliation(s)
- Pei Y Ng
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Taylor L McNeely
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Darren J Baker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.,Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
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27
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Homeostasis of carbohydrates and reactive oxygen species is critically changed in the brain of middle-aged mice: molecular mechanisms and functional reasons. BBA ADVANCES 2023; 3:100077. [PMID: 37082254 PMCID: PMC10074963 DOI: 10.1016/j.bbadva.2023.100077] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 01/23/2023] Open
Abstract
The brain is an organ that consumes a lot of energy. In the brain, energy is required for synaptic transmission, numerous biosynthetic processes and axonal transport in neurons, and for many supportive functions of glial cells. The main source of energy in the brain is glucose and to a lesser extent lactate and ketone bodies. ATP is formed at glucose catabolism via glycolysis and oxidative phosphorylation in mitochondrial electron transport chain (ETC) within mitochondria being the main source of ATP. With age, brain's energy metabolism is disturbed, involving a decrease in glycolysis and mitochondrial dysfunction. The latter is accompanied by intensified generation of reactive oxygen species (ROS) in ETC leading to oxidative stress. Recently, we have found that crucial changes in energy metabolism and intensity of oxidative stress in the mouse brain occur in middle age with minor progression in old age. In this review, we analyze the metabolic changes and functional causes that lead to these changes in the aging brain.
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28
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Park H, Shin JA, Lim J, Lee S, Ahn JH, Kang JL, Choi YH. Increased Caveolin-2 Expression in Brain Endothelial Cells Promotes Age-Related Neuroinflammation. Mol Cells 2022; 45:950-962. [PMID: 36572563 PMCID: PMC9794556 DOI: 10.14348/molcells.2022.0045] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/30/2022] [Accepted: 10/12/2022] [Indexed: 12/28/2022] Open
Abstract
Aging is a major risk factor for common neurodegenerative diseases. Although multiple molecular, cellular, structural, and functional changes occur in the brain during aging, the involvement of caveolin-2 (Cav-2) in brain ageing remains unknown. We investigated Cav-2 expression in brains of aged mice and its effects on endothelial cells. The human umbilical vein endothelial cells (HUVECs) showed decreased THP-1 adhesion and infiltration when treated with Cav-2 siRNA compared to control siRNA. In contrast, Cav-2 overexpression increased THP-1 adhesion and infiltration in HUVECs. Increased expression of Cav-2 and iba-1 was observed in brains of old mice. Moreover, there were fewer iba-1-positive cells in the brains of aged Cav-2 knockout (KO) mice than of wild-type aged mice. The levels of several chemokines were higher in brains of aged wild-type mice than in young wild-type mice; moreover, chemokine levels were significantly lower in brains of young mice as well as aged Cav-2 KO mice than in their wild-type counterparts. Expression of PECAM1 and VE-cadherin proteins increased in brains of old wild-type mice but was barely detected in brains of young wild-type and Cav-2 KO mice. Collectively, our results suggest that Cav-2 expression increases in the endothelial cells of aged brain, and promotes leukocyte infiltration and age-associated neuroinflammation.
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Affiliation(s)
- Hyunju Park
- Department of Physiology, Inflammation-Cancer Microenvironment Research Center, Seoul 07804, Korea
| | - Jung A Shin
- Department of Anatomy, Ewha Womans University College of Medicine, Seoul 07804, Korea
| | - Jiwoo Lim
- Department of Physiology, Inflammation-Cancer Microenvironment Research Center, Seoul 07804, Korea
| | - Seulgi Lee
- Department of Physiology, Inflammation-Cancer Microenvironment Research Center, Seoul 07804, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul 07804, Korea
| | - Jihee Lee Kang
- Department of Physiology, Inflammation-Cancer Microenvironment Research Center, Seoul 07804, Korea
| | - Youn-Hee Choi
- Department of Physiology, Inflammation-Cancer Microenvironment Research Center, Seoul 07804, Korea
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29
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Modulation of the Microglial Nogo-A/NgR Signaling Pathway as a Therapeutic Target for Multiple Sclerosis. Cells 2022; 11:cells11233768. [PMID: 36497029 PMCID: PMC9737582 DOI: 10.3390/cells11233768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Current therapeutics targeting chronic phases of multiple sclerosis (MS) are considerably limited in reversing the neural damage resulting from repeated inflammation and demyelination insults in the multi-focal lesions. This inflammation is propagated by the activation of microglia, the endogenous immune cell aiding in the central nervous system homeostasis. Activated microglia may transition into polarized phenotypes; namely, the classically activated proinflammatory phenotype (previously categorized as M1) and the alternatively activated anti-inflammatory phenotype (previously, M2). These transitional microglial phenotypes are dynamic states, existing as a continuum. Shifting microglial polarization to an anti-inflammatory status may be a potential therapeutic strategy that can be harnessed to limit neuroinflammation and further neurodegeneration in MS. Our research has observed that the obstruction of signaling by inhibitory myelin proteins such as myelin-associated inhibitory factor, Nogo-A, with its receptor (NgR), can regulate microglial cell function and activity in pre-clinical animal studies. Our review explores the microglial role and polarization in MS pathology. Additionally, the potential therapeutics of targeting Nogo-A/NgR cellular mechanisms on microglia migration, polarization and phagocytosis for neurorepair in MS and other demyelination diseases will be discussed.
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30
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Van Avondt K, Strecker J, Tulotta C, Minnerup J, Schulz C, Soehnlein O. Neutrophils in aging and aging‐related pathologies. Immunol Rev 2022; 314:357-375. [PMID: 36315403 DOI: 10.1111/imr.13153] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Over the past millennia, life expectancy has drastically increased. While a mere 25 years during Bronze and Iron ages, life expectancy in many European countries and in Japan is currently above 80 years. Such an increase in life expectancy is a result of improved diet, life style, and medical care. Yet, increased life span and aging also represent the most important non-modifiable risk factors for several pathologies including cardiovascular disease, neurodegenerative diseases, and cancer. In recent years, neutrophils have been implicated in all of these pathologies. Hence, this review provides an overview of how aging impacts neutrophil production and function and conversely how neutrophils drive aging-associated pathologies. Finally, we provide a perspective on how processes of neutrophil-driven pathologies in the context of aging can be targeted therapeutically.
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Affiliation(s)
- Kristof Van Avondt
- Institute of Experimental Pathology (ExPat), Centre of Molecular Biology of Inflammation (ZMBE) University of Münster Münster Germany
| | - Jan‐Kolja Strecker
- Department of Neurology with Institute of Translational Neurology University Hospital Münster Münster Germany
| | - Claudia Tulotta
- Institute of Experimental Pathology (ExPat), Centre of Molecular Biology of Inflammation (ZMBE) University of Münster Münster Germany
| | - Jens Minnerup
- Department of Neurology with Institute of Translational Neurology University Hospital Münster Münster Germany
| | - Christian Schulz
- Department of Medicine I University Hospital, Ludwig Maximilian University Munich Germany
- DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance Munich Germany
| | - Oliver Soehnlein
- Institute of Experimental Pathology (ExPat), Centre of Molecular Biology of Inflammation (ZMBE) University of Münster Münster Germany
- Department of Physiology and Pharmacology (FyFa) Karolinska Institute Stockholm Sweden
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31
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Maguire E, Connor-Robson N, Shaw B, O’Donoghue R, Stöberl N, Hall-Roberts H. Assaying Microglia Functions In Vitro. Cells 2022; 11:3414. [PMID: 36359810 PMCID: PMC9654693 DOI: 10.3390/cells11213414] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 08/27/2023] Open
Abstract
Microglia, the main immune modulators of the central nervous system, have key roles in both the developing and adult brain. These functions include shaping healthy neuronal networks, carrying out immune surveillance, mediating inflammatory responses, and disposing of unwanted material. A wide variety of pathological conditions present with microglia dysregulation, highlighting the importance of these cells in both normal brain function and disease. Studies into microglial function in the context of both health and disease thus have the potential to provide tremendous insight across a broad range of research areas. In vitro culture of microglia, using primary cells, cell lines, or induced pluripotent stem cell derived microglia, allows researchers to generate reproducible, robust, and quantifiable data regarding microglia function. A broad range of assays have been successfully developed and optimised for characterizing microglial morphology, mediation of inflammation, endocytosis, phagocytosis, chemotaxis and random motility, and mediation of immunometabolism. This review describes the main functions of microglia, compares existing protocols for measuring these functions in vitro, and highlights common pitfalls and future areas for development. We aim to provide a comprehensive methodological guide for researchers planning to characterise microglial functions within a range of contexts and in vitro models.
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Affiliation(s)
- Emily Maguire
- UK Dementia Research Institute (UK DRI), School of Medicine, Cardiff University, Cardiff CF10 3AT, UK
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32
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Auzmendi-Iriarte J, Moreno-Cugnon L, Saenz-Antoñanzas A, Grassi D, de Pancorbo MM, Arevalo MA, Wood IC, Matheu A. High levels of HDAC expression correlate with microglial aging. Expert Opin Ther Targets 2022; 26:911-922. [PMID: 36503367 DOI: 10.1080/14728222.2022.2158081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Cellular damage gradually accumulates with aging, promoting a time-dependent functional decline of the brain. Microglia play an essential regulatory role in maintaining cognitive activity by phagocytosing cell debris and apoptotic cells during neurogenesis. The activities of different histone deacetylases (HDACs) regulate microglial function during development and neurodegeneration. However, no studies have described the role of HDACs in microglia during physiological aging. RESEARCH DESIGN AND METHODS HDAC and microglial marker levels were examined in microglial cells after inducing senescence in vitro and in mouse and human hippocampal biopsies in vivo, using quantitative real-time PCR. Publicly available datasets were used to determine HDAC expression in different brain areas during physiological aging. RESULTS HDAC expression increased upon the induction of senescence with bleomycin or serial passage in microglial cultures. High levels of HDACs were detected in mice and aged human brain samples. Human hippocampal samples showed a positive correlation between the expression of HDAC1, 3, and 7 and microglial and senescence markers. HDAC1 and 3 levels are enriched in the purified aged microglial population. CONCLUSIONS Several HDACs, particularly HDAC1, are elevated in microglia upon senescence induction in vitro and with aging in vivo, and correlate with microglial and senescence biomarkers.
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Affiliation(s)
| | - Leire Moreno-Cugnon
- Cellular Oncology Group, Biodonostia Health Research Institute, San Sebastian, Spain
| | | | - Daniela Grassi
- Department of Anatomy, Histology and Neuroscience, Autonoma University of Madrid, Madrid, Spain.,Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain
| | - Marian M de Pancorbo
- BIOMICs Research Group, Lascaray Research Center, University of the Basque Country, Vitoria, Spain
| | - Maria-Angeles Arevalo
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain.,CIBER de Fragilidad y Envejecimiento Saludable (CIBERfes), Madrid, Spain
| | - Ian C Wood
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Ander Matheu
- Cellular Oncology Group, Biodonostia Health Research Institute, San Sebastian, Spain.,CIBER de Fragilidad y Envejecimiento Saludable (CIBERfes), Madrid, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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33
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Britton R, Liu AT, Rege SV, Adams JM, Akrapongpisak L, Le D, Alcantara-Lee R, Estrada RA, Ray R, Ahadi S, Gallager I, Yang CF, Minami SS, Braithwaite SP, Czirr E, Campbell MK. Molecular and histological correlates of cognitive decline across age in male C57BL/6J mice. Brain Behav 2022; 12:e2736. [PMID: 35971662 PMCID: PMC9480918 DOI: 10.1002/brb3.2736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 07/01/2022] [Accepted: 07/20/2022] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Increasing age is the number one risk factor for developing cognitive decline and neurodegenerative disease. Aged humans and mice exhibit numerous molecular changes that contribute to a decline in cognitive function and increased risk of developing age-associated diseases. Here, we characterize multiple age-associated changes in male C57BL/6J mice to understand the translational utility of mouse aging. METHODS Male C57BL/6J mice from various ages between 2 and 24 months of age were used to assess behavioral, as well as, histological and molecular changes across three modalities: neuronal, microgliosis/neuroinflammation, and the neurovascular unit (NVU). Additionally, a cohort of 4- and 22-month-old mice was used to assess blood-brain barrier (BBB) breakdown. Mice in this cohort were treated with a high, acute dose of lipopolysaccharide (LPS, 10 mg/kg) or saline control 6 h prior to sacrifice followed by tail vein injection of 0.4 kDa sodium fluorescein (100 mg/kg) 2 h later. RESULTS Aged mice showed a decline in cognitive and motor abilities alongside decreased neurogenesis, proliferation, and synapse density. Further, neuroinflammation and circulating proinflammatory cytokines were increased in aged mice. Additionally, we found changes at the BBB, including increased T cell infiltration in multiple brain regions and an exacerbation in BBB leakiness following chemical insult with age. There were also a number of readouts that were unchanged with age and have limited utility as markers of aging in male C57BL/6J mice. CONCLUSIONS Here we propose that these changes may be used as molecular and histological readouts that correspond to aging-related behavioral decline. These comprehensive findings, in the context of the published literature, are an important resource toward deepening our understanding of normal aging and provide an important tool for studying aging in mice.
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Affiliation(s)
| | - Angela T Liu
- Alkahest, Inc., San Carlos, California, USA.,Coda Biotherapeutics, South San Francisco, California, USA
| | | | | | - Lily Akrapongpisak
- Alkahest, Inc., San Carlos, California, USA.,University of Queensland, Herston, Queensland, Australia
| | - David Le
- Alkahest, Inc., San Carlos, California, USA.,Fountain Therapeutics, South San Francisco, California, USA
| | | | | | - Rebecca Ray
- Alkahest, Inc., San Carlos, California, USA.,202 Chives Way, Walnut Creek, California, USA
| | - Sara Ahadi
- Alkahest, Inc., San Carlos, California, USA
| | | | | | | | | | - Eva Czirr
- Alkahest, Inc., San Carlos, California, USA.,Confluence Therapeutics, South San Francisco, California, USA
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34
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Bi Q, Wang C, Cheng G, Chen N, Wei B, Liu X, Li L, Lu C, He J, Weng Y, Yin C, Lin Y, Wan S, Zhao L, Xu J, Wang Y, Gu Y, Shen XZ, Shi P. Microglia-derived PDGFB promotes neuronal potassium currents to suppress basal sympathetic tonicity and limit hypertension. Immunity 2022; 55:1466-1482.e9. [PMID: 35863346 DOI: 10.1016/j.immuni.2022.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/05/2022] [Accepted: 06/22/2022] [Indexed: 12/18/2022]
Abstract
Although many studies have addressed the regulatory circuits affecting neuronal activities, local non-synaptic mechanisms that determine neuronal excitability remain unclear. Here, we found that microglia prevented overactivation of pre-sympathetic neurons in the hypothalamic paraventricular nucleus (PVN) at steady state. Microglia constitutively released platelet-derived growth factor (PDGF) B, which signaled via PDGFRα on neuronal cells and promoted their expression of Kv4.3, a key subunit that conducts potassium currents. Ablation of microglia, conditional deletion of microglial PDGFB, or suppression of neuronal PDGFRα expression in the PVN elevated the excitability of pre-sympathetic neurons and sympathetic outflow, resulting in a profound autonomic dysfunction. Disruption of the PDGFBMG-Kv4.3Neuron pathway predisposed mice to develop hypertension, whereas central supplementation of exogenous PDGFB suppressed pressor response when mice were under hypertensive insult. Our results point to a non-immune action of resident microglia in maintaining the balance of sympathetic outflow, which is important in preventing cardiovascular diseases.
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Affiliation(s)
- Qianqian Bi
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Chao Wang
- Center of Stem Cell and Regenerative Medicine and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Guo Cheng
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Ningting Chen
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Bo Wei
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaoli Liu
- Department of Neurology, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Li Li
- Department of Pharmacy, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310013, China
| | - Cheng Lu
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jian He
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yuancheng Weng
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Chunyou Yin
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yunfan Lin
- Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Haining, Zhejiang 314400, China
| | - Shu Wan
- Brain Center, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Li Zhao
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jiaxi Xu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shanxi 710061, China
| | - Yi Wang
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yan Gu
- Center of Stem Cell and Regenerative Medicine and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Xiao Z Shen
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
| | - Peng Shi
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
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Bosch LFP, Kierdorf K. The Shape of μ—How Morphological Analyses Shape the Study of Microglia. Front Cell Neurosci 2022; 16:942462. [PMID: 35846562 PMCID: PMC9276927 DOI: 10.3389/fncel.2022.942462] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/13/2022] [Indexed: 11/14/2022] Open
Abstract
Microglia, the innate immune cells of the CNS parenchyma, serve as the first line of defense in a myriad of neurodevelopmental, neurodegenerative, and neuroinflammatory conditions. In response to the peripheral inflammation, circulating mediators, and other external signals that are produced by these conditions, microglia dynamically employ different transcriptional programs as well as morphological adaptations to maintain homeostasis. To understand these cells’ function, the field has established a number of essential analysis approaches, such as gene expression, cell quantification, and morphological reconstruction. Although high-throughput approaches are becoming commonplace in regard to other types of analyses (e.g., single-cell scRNA-seq), a similar standard for morphological reconstruction has yet to be established. In this review, we offer an overview of microglial morphological analysis methods, exploring the advantages and disadvantages of each, highlighting a number of key studies, and emphasizing how morphological analysis has significantly contributed to our understanding of microglial function in the CNS parenchyma. In doing so, we advocate for the use of unbiased, automated morphological reconstruction approaches in future studies, in order to capitalize on the valuable information embedded in the cellular structures microglia inhabit.
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Affiliation(s)
- Lance Fredrick Pahutan Bosch
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS–Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- *Correspondence: Katrin Kierdorf,
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36
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Ridderinkhof KR, Krugers HJ. Horizons in Human Aging Neuroscience: From Normal Neural Aging to Mental (Fr)Agility. Front Hum Neurosci 2022; 16:815759. [PMID: 35845248 PMCID: PMC9277589 DOI: 10.3389/fnhum.2022.815759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/19/2022] [Indexed: 11/13/2022] Open
Abstract
While aging is an important risk factor for neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease, age-related cognitive decline can also manifest without apparent neurodegenerative changes. In this review, we discuss molecular, cellular, and network changes that occur during normal aging in the absence of neurodegenerative disease. Emerging findings reveal that these changes include metabolic alterations, oxidative stress, DNA damage, inflammation, calcium dyshomeostasis, and several other hallmarks of age-related neural changes that do not act on their own, but are often interconnected and together may underlie age-related alterations in brain plasticity and cognitive function. Importantly, age-related cognitive decline may not be reduced to a single neurobiological cause, but should instead be considered in terms of a densely connected system that underlies age-related cognitive alterations. We speculate that a decline in one hallmark of neural aging may trigger a decline in other, otherwise thus far stable subsystems, thereby triggering a cascade that may at some point also incur a decline of cognitive functions and mental well-being. Beyond studying the effects of these factors in isolation, considerable insight may be gained by studying the larger picture that entails a representative collection of such factors and their interactions, ranging from molecules to neural networks. Finally, we discuss some potential interventions that may help to prevent these alterations, thereby reducing cognitive decline and mental fragility, and enhancing mental well-being, and healthy aging.
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Affiliation(s)
- K Richard Ridderinkhof
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Center for Brain and Cognition (ABC), University of Amsterdam, Amsterdam, Netherlands
| | - Harm J Krugers
- Amsterdam Center for Brain and Cognition (ABC), University of Amsterdam, Amsterdam, Netherlands
- SILS-CNS, Faculty of Science, University of Amsterdam, Amsterdam, Netherlands
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Wlodarek L, Alibhai FJ, Wu J, Li SH, Li RK. Stroke-Induced Neurological Dysfunction in Aged Mice Is Attenuated by Preconditioning with Young Sca-1+ Stem Cells. Stem Cells 2022; 40:564-576. [PMID: 35291015 PMCID: PMC9216491 DOI: 10.1093/stmcls/sxac019] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022]
Abstract
AIMS To date, stroke remains one of the leading causes of death and disability worldwide. Nearly three-quarters of all strokes occur in the elderly (>65 years old), and a vast majority of these individuals develop debilitating cognitive impairments that can later progress into dementia. Currently, there are no therapies capable of reversing the cognitive complications which arise following a stroke. Instead, current treatment options focus on preventing secondary injuries, as opposed to improving functional recovery. METHODS We reconstituted aged (20-month old) mice with Sca-1+ bone marrow (BM) hematopoietic stem cells isolated from aged or young (2-month old) EGFP+ donor mice. Three months later the chimeric aged mice underwent cerebral ischemia/reperfusion by bilateral common carotid artery occlusion (BCCAO), after which cognitive function was evaluated. Immunohistochemical analysis was performed to evaluate host and recipient cells in the brain following BCCAO. RESULTS Young Sca-1+ cells migrate to the aged brain and give rise to beneficial microglial-like cells that ameliorate stroke-induced loss of cognitive function on tasks targeting the hippocampus and cerebellum. We also found that young Sca-1+ cell-derived microglial-like cells possess neuroprotective properties as they do not undergo microgliosis upon migrating to the ischemic hippocampus, whereas the cells originating from old Sca-1+ cells proliferate extensively and skew toward a pro-inflammatory phenotype following injury. CONCLUSIONS This study provides a proof-of-principle demonstrating that young BM Sca-1+ cells play a pivotal role in reversing stroke-induced cognitive impairments and protect the aged brain against secondary injury by attenuating the host cell response to injury.
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Affiliation(s)
- Lukasz Wlodarek
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada.,Faculty of Medicine, Department weof Physiology, University of Toronto, Toronto, ON, Canada
| | - Faisal J Alibhai
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada
| | - Jun Wu
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada
| | - Shu-Hong Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada
| | - Ren-Ke Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada.,Faculty of Medicine, Department weof Physiology, University of Toronto, Toronto, ON, Canada.,Division of Cardiac Surgery, Department of Surgery, University of Toronto, Toronto, ON, Canada
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Lima MN, Barbosa-Silva MC, Maron-Gutierrez T. Microglial Priming in Infections and Its Risk to Neurodegenerative Diseases. Front Cell Neurosci 2022; 16:878987. [PMID: 35783096 PMCID: PMC9240317 DOI: 10.3389/fncel.2022.878987] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/26/2022] [Indexed: 11/29/2022] Open
Abstract
Infectious diseases of different etiologies have been associated with acute and long-term neurological consequences. The primary cause of these consequences appears to be an inflammatory process characterized primarily by a pro-inflammatory microglial state. Microglial cells, the local effectors’ cells of innate immunity, once faced by a stimulus, alter their morphology, and become a primary source of inflammatory cytokines that increase the inflammatory process of the brain. This inflammatory scenario exerts a critical role in the pathogenesis of neurodegenerative diseases. In recent years, several studies have shown the involvement of the microglial inflammatory response caused by infections in the development of neurodegenerative diseases. This has been associated with a transitory microglial state subsequent to an inflammatory response, known as microglial priming, in which these cells are more responsive to stimuli. Thus, systemic inflammation and infections induce a transitory state in microglia that may lead to changes in their state and function, making priming them for subsequent immune challenges. However, considering that microglia are long-lived cells and are repeatedly exposed to infections during a lifetime, microglial priming may not be beneficial. In this review, we discuss the relationship between infections and neurodegenerative diseases and how this may rely on microglial priming.
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Affiliation(s)
- Maiara N. Lima
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Maria C. Barbosa-Silva
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Tatiana Maron-Gutierrez
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation, Rio de Janeiro, Brazil
- *Correspondence: Tatiana Maron-Gutierrez;
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Microglia in Alzheimer’s Disease: A Favorable Cellular Target to Ameliorate Alzheimer’s Pathogenesis. Mediators Inflamm 2022; 2022:6052932. [PMID: 35693110 PMCID: PMC9184163 DOI: 10.1155/2022/6052932] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 05/09/2022] [Indexed: 11/18/2022] Open
Abstract
Microglial cells serve as molecular sensors of the brain that play a role in physiological and pathological conditions. Under normal physiology, microglia are primarily responsible for regulating central nervous system homeostasis through the phagocytic clearance of redundant protein aggregates, apoptotic cells, damaged neurons, and synapses. Furthermore, microglial cells can promote and mitigate amyloid β phagocytosis and tau phosphorylation. Dysregulation of the microglial programming alters cellular morphology, molecular signaling, and secretory inflammatory molecules that contribute to various neurodegenerative disorders especially Alzheimer’s disease (AD). Furthermore, microglia are considered primary sources of inflammatory molecules and can induce or regulate a broad spectrum of cellular responses. Interestingly, in AD, microglia play a double-edged role in disease progression; for instance, the detrimental microglial effects increase in AD while microglial beneficiary mechanisms are jeopardized. Depending on the disease stages, microglial cells are expressed differently, which may open new avenues for AD therapy. However, the disease-related role of microglial cells and their receptors in the AD brain remain unclear. Therefore, this review represents the role of microglial cells and their involvement in AD pathogenesis.
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40
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Dong Y, Jain RW, Lozinski BM, D'Mello C, Visser F, Ghorbani S, Zandee S, Brown DI, Prat A, Xue M, Yong VW. Single-cell and spatial RNA sequencing identify perturbators of microglial functions with aging. NATURE AGING 2022; 2:508-525. [PMID: 37118444 DOI: 10.1038/s43587-022-00205-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 03/11/2022] [Indexed: 04/30/2023]
Abstract
Microglia are the immune sentinels of the central nervous system with protective roles such as the removal of neurotoxic oxidized phosphatidylcholines (OxPCs). As aging alters microglial function and elevates neurological disability in diseases such as multiple sclerosis, defining aging-associated factors that cause microglia to lose their custodial properties or even become injurious can help to restore their homeostasis. We used single-cell and spatial RNA sequencing in the spinal cord of young (6-week-old) and middle-aged (52-week-old) mice to determine aging-driven microglial reprogramming at homeostasis or after OxPC injury. We identified numerous aging-associated microglial transcripts including osteopontin elevated in OxPC-treated 52-week-old mice, which correlated with greater neurodegeneration. Osteopontin delivery into the spinal cords of 6-week-old mice worsened OxPC lesions, while its knockdown in 52-week-old lesions attenuated microglial inflammation and axon loss. Thus, elevation of osteopontin and other transcripts in aging disorders including multiple sclerosis perturbs microglial functions contributing to aging-associated neurodegeneration.
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Affiliation(s)
- Yifei Dong
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Rajiv W Jain
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Brian M Lozinski
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Charlotte D'Mello
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Frank Visser
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Samira Ghorbani
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Stephanie Zandee
- Neuroimmunology Unit, The Research Center of the Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Dennis I Brown
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Alexandre Prat
- Neuroimmunology Unit, The Research Center of the Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Mengzhou Xue
- Departments of Cerebrovascular Diseases and Anesthesiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - V Wee Yong
- Hotchkiss Brain Institute and the Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada.
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Rocha SM, Bantle CM, Aboellail T, Chatterjee D, Smeyne RJ, Tjalkens RB. Rotenone induces regionally distinct α-synuclein protein aggregation and activation of glia prior to loss of dopaminergic neurons in C57Bl/6 mice. Neurobiol Dis 2022; 167:105685. [DOI: 10.1016/j.nbd.2022.105685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/14/2022] [Accepted: 03/02/2022] [Indexed: 12/21/2022] Open
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Oroszi T, de Boer SF, Nyakas C, Schoemaker RG, van der Zee EA. Chronic whole body vibration ameliorates hippocampal neuroinflammation, anxiety-like behavior, memory functions and motor performance in aged male rats dose dependently. Sci Rep 2022; 12:9020. [PMID: 35637277 PMCID: PMC9151803 DOI: 10.1038/s41598-022-13178-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/13/2022] [Indexed: 12/19/2022] Open
Abstract
AbstractWhole body vibration (WBV) is a form of passive exercise by the stimulation of mechanical vibration platform. WBV has been extensively investigated through clinical studies with main focus on the musculoskeletal system. However, pre-clinical data in the context of behavior, memory and motor functions with aged rodents are limited. The aim of this experiment was to investigate the dose dependent effects of a five weeks long WBV intervention with an aged animal model including anxiety-related behavior, memory and motor functions, as well as markers of (neuro)inflammation. Male Wistar rats (18 months) underwent 5 or 20 min daily vibration exposure or pseudo-treatment (i.e.: being subjected to the same environmental stimuli for 5 or 20 min, but without exposure to vibrations) 5 times per week. After 5 weeks treatment, cognitive functions, anxiety-like behavior and motor performance were evaluated. Finally, brain tissue was collected for immunohistological purposes to evaluate hippocampal (neuro)inflammation. Animals with 20 min daily session of WBV showed a decrease in their anxiety-like behavior and improvement in their spatial memory. Muscle strength in the grip hanging test was only significantly improved by 5 min daily WBV treatments, whereas motor coordination in the balance beam test was not significantly altered. Microglia activation showed a significant decrease in the CA1 and Dentate gyrus subregions by both dose of WBV. In contrast, these effects were less pronounced in the CA3 and Hilus subregions, where only 5 min dose showed a significant effect on microglia activation. Our results indicate, that WBV seems to be a comparable strategy on age-related anxiety, cognitive and motor decline, as well as alleviating age-related (neuro)inflammation.
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Gonçalves de Andrade E, González Ibáñez F, Tremblay MÈ. Microglia as a Hub for Suicide Neuropathology: Future Investigation and Prevention Targets. Front Cell Neurosci 2022; 16:839396. [PMID: 35663424 PMCID: PMC9158339 DOI: 10.3389/fncel.2022.839396] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
Suicide is a complex public health challenge associated worldwide with one death every 40 s. Research advances in the neuropathology of suicidal behaviors (SB) have defined discrete brain changes which may hold the key to suicide prevention. Physiological differences in microglia, the resident immune cells of the brain, are present in post-mortem tissue samples of individuals who died by suicide. Furthermore, microglia are mechanistically implicated in the outcomes of important risk factors for SB, including early-life adversity, stressful life events, and psychiatric disorders. SB risk factors result in inflammatory and oxidative stress activities which could converge to microglial synaptic remodeling affecting susceptibility or resistance to SB. To push further this perspective, in this Review we summarize current areas of opportunity that could untangle the functional participation of microglia in the context of suicide. Our discussion centers around microglial state diversity in respect to morphology, gene and protein expression, as well as function, depending on various factors, namely brain region, age, and sex.
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Affiliation(s)
- Elisa Gonçalves de Andrade
- Neuroscience Graduate Program, Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Fernando González Ibáñez
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- *Correspondence: Marie-Ève Tremblay,
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Songkiatisak P, Rahman SMT, Aqdas M, Sung MH. NF-κB, a culprit of both inflamm-ageing and declining immunity? Immun Ageing 2022; 19:20. [PMID: 35581646 PMCID: PMC9112493 DOI: 10.1186/s12979-022-00277-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/29/2022] [Indexed: 04/21/2023]
Abstract
NF-κB is generally recognized as an important regulator of ageing, through its roles in cellular senescence and inflammatory pathways. Activated in virtually all cell-cell communication networks of the immune system, NF-κB is thought to affect age-related defects of both innate and adaptive immune cells, relevant to inflamm-ageing and declining adaptive immunity, respectively. Moreover, the family of NF-κB proteins that exist as heterodimers and homodimers exert their function beyond the immune system. Given their involvement in diverse areas such as DNA damage to metabolism, NF-κB has the potential to serve as linkages between known hallmarks of ageing. However, the complexity of NF-κB dimer composition, dynamic signaling, and tissue-specific actions has received relatively little attention in ageing research. Here, we discuss some areas where further research may bear fruit in our understanding the impact of NF-κB in healthy ageing and longevity.
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Affiliation(s)
- Preeyaporn Songkiatisak
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, 21224, Baltimore, MD, USA
| | - Shah Md Toufiqur Rahman
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, 21224, Baltimore, MD, USA
| | - Mohammad Aqdas
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, 21224, Baltimore, MD, USA
| | - Myong-Hee Sung
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, 21224, Baltimore, MD, USA.
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Moca EN, Lecca D, Hope KT, Etienne F, Schaler AW, Espinoza K, Chappell MS, Gray DT, Tweedie D, Sidhu S, Masukawa L, Sitoy H, Mathew R, Saban DR, Greig NH, De Biase LM. Microglia Drive Pockets of Neuroinflammation in Middle Age. J Neurosci 2022; 42:3896-3918. [PMID: 35396327 PMCID: PMC9097782 DOI: 10.1523/jneurosci.1922-21.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/18/2022] [Accepted: 03/14/2022] [Indexed: 11/21/2022] Open
Abstract
During aging, microglia produce inflammatory factors, show reduced tissue surveillance, altered interactions with synapses, and prolonged responses to CNS insults, positioning these cells to have profound impact on the function of nearby neurons. We and others recently showed that microglial attributes differ significantly across brain regions in young adult mice. However, the degree to which microglial properties vary during aging is largely unexplored. Here, we analyze and manipulate microglial aging within the basal ganglia, brain circuits that exhibit prominent regional microglial heterogeneity and where neurons are vulnerable to functional decline and neurodegenerative disease. In male and female mice, we demonstrate that VTA and SNc microglia exhibit unique and premature responses to aging, compared with cortex and NAc microglia. This is associated with localized VTA/SNc neuroinflammation that may compromise synaptic function as early as middle age. Surprisingly, systemic inflammation, local neuron death, and astrocyte aging do not appear to underlie these early aging responses of VTA and SNc microglia. Instead, we found that microglial lysosome status was tightly linked to early aging of VTA microglia. Microglial ablation/repopulation normalized VTA microglial lysosome swelling and suppressed increases in VTA microglial density during aging. In contrast, CX3CR1 receptor KO exacerbated VTA microglial lysosome rearrangements and VTA microglial proliferation during aging. Our findings reveal a previously unappreciated regional variation in onset and magnitude of microglial proliferation and inflammatory factor production during aging and highlight critical links between microglial lysosome status and local microglial responses to aging.SIGNIFICANCE STATEMENT Microglia are CNS cells that are equipped to regulate neuronal health and function throughout the lifespan. We reveal that microglia in select brain regions begin to proliferate and produce inflammatory factors in late middle age, months before microglia in other brain regions. These findings demonstrate that CNS neuroinflammation during aging is not uniform. Moreover, they raise the possibility that local microglial responses to aging play a critical role in determining which populations of neurons are most vulnerable to functional decline and neurodegenerative disease.
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Affiliation(s)
- Eric N Moca
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Daniela Lecca
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland 21224
| | - Keenan T Hope
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Fanny Etienne
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Ari W Schaler
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Katherine Espinoza
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Megan S Chappell
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Daniel T Gray
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - David Tweedie
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland 21224
| | - Shanaya Sidhu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Lindsay Masukawa
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Hannah Sitoy
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Rose Mathew
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Daniel R Saban
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Nigel H Greig
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland 21224
| | - Lindsay M De Biase
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
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Jiang X, Xu Z, Yao D, Liu X, Liu W, Wang N, Li X, Diao Y, Zhang Y, Zhao Q. An integrated multi-omics approach revealed the regulation of melatonin on age-dependent mitochondrial function impair and lipid dyshomeostasis in mice hippocampus. Pharmacol Res 2022; 179:106210. [DOI: 10.1016/j.phrs.2022.106210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/24/2022] [Accepted: 04/03/2022] [Indexed: 01/01/2023]
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Guo L, Choi S, Bikkannavar P, Cordeiro MF. Microglia: Key Players in Retinal Ageing and Neurodegeneration. Front Cell Neurosci 2022; 16:804782. [PMID: 35370560 PMCID: PMC8968040 DOI: 10.3389/fncel.2022.804782] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/11/2022] [Indexed: 12/20/2022] Open
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) and play a key role in maintaining the normal function of the retina and brain. During early development, microglia migrate into the retina, transform into a highly ramified phenotype, and scan their environment constantly. Microglia can be activated by any homeostatic disturbance that may endanger neurons and threaten tissue integrity. Once activated, the young microglia exhibit a high diversity in their phenotypes as well as their functions, which relate to either beneficial or harmful consequences. Microglial activation is associated with the release of cytokines, chemokines, and growth factors that can determine pathological outcomes. As the professional phagocytes in the retina, microglia are responsible for the clearance of pathogens, dead cells, and protein aggregates. However, their phenotypic diversity and phagocytic capacity is compromised with ageing. This may result in the accumulation of protein aggregates and myelin debris leading to retinal neuroinflammation and neurodegeneration. In this review, we describe microglial phenotypes and functions in the context of the young and ageing retina, and the mechanisms underlying changes in ageing. Additionally, we review microglia-mediated retinal neuroinflammation and discuss the mechanisms of microglial involvement in retinal neurodegenerative diseases.
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Affiliation(s)
- Li Guo
- Institute of Ophthalmology, University College London, London, United Kingdom
- *Correspondence: Li Guo,
| | - Soyoung Choi
- Institute of Ophthalmology, University College London, London, United Kingdom
| | | | - M. Francesca Cordeiro
- Institute of Ophthalmology, University College London, London, United Kingdom
- Imperial College Ophthalmology Research Group, Imperial College London, London, United Kingdom
- M. Francesca Cordeiro,
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Pharmacological depletion of microglia leads to a dose-dependent reduction in inflammation and senescence in the aged murine brain. Neuroscience 2022; 488:1-9. [PMID: 35217122 DOI: 10.1016/j.neuroscience.2022.02.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 12/16/2022]
Abstract
Chronic macrophage activation was implicated as one of the main culprits for chronical, low-grade inflammation which significantly contributes to development of age-related diseases. Microglia as the brain macrophages have been recently implicated as key players in neuroinflammation and neurodegeneration in the aged brain. Microglial cell functions are indispensable in early development, however, activation or senescence of microglia in aging cells may be detrimental. Depletion of microglia using genetical or pharmacological approaches leads to opposite results regarding effects on brain cognition. In this study we pharmacologically depleted microglia using orally delivered low and high doses of the CSF1R inhibitor PLX5622 and assessed the expression levels of known inflammation markers (TNF-α, IL1-β, IL-6, IL-10), glia markers (Iba-1 and Gfap) and specific senescence marker p16Ink4a in the aged murine brain. Our results indicate that treatment with low and high doses of PLX5622 leads to a dose-dependent depletion of microglial cells with similar levels in young and aged mice. We also show that treatment with low and high PLX5622 differentially affected cytokine levels in young and old brains. By using low doses we could achieve reduction in inflammation circumventing the astrocyte activation. Removal of microglia cells led to decreased expression of the senescence marker p16Ink4a in the aged brain, indicating a relevant contribution of these cells to the expression of this marker and their senescent status in the healthy aging brain. Our results indicate that increased and detrimental brain inflammation in aged murine brain can be impaired by selectively reducing the microglial cell population.
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Zhuang H, Yao X, Li H, Li Q, Yang C, Wang C, Xu D, Xiao Y, Gao Y, Gao J, Bi M, Liu R, Teng G, Liu L. Long-term high-fat diet consumption by mice throughout adulthood induces neurobehavioral alterations and hippocampal neuronal remodeling accompanied by augmented microglial lipid accumulation. Brain Behav Immun 2022; 100:155-171. [PMID: 34848340 DOI: 10.1016/j.bbi.2021.11.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 01/01/2023] Open
Abstract
High-fat diet (HFD) consumption is generally associated with an increased risk of cognitive and emotional dysfunctions that constitute a sizeable worldwide health burden with profound social and economic consequences. Middle age is a critical time period that affects one's health later in life; pertinently, the prevalence of HFD consumption is increasing among mature adults. Given the growing health-related economic burden imposed globally by increasing rates of noncommunicable diseases in rapidly aging populations, along with the pervasive but insidious health impairments associated with HFD consumption, it is critically important to understand the effects of long-term HFD consumption on brain function and to gain insights into their potential underlying mechanisms. In the present study, adult male C57BL/6J mice were randomly assigned a control diet (CD, 10 kJ% from fat) or an HFD (60 kJ% from fat) for 6 months (6 M) or 9 months (9 M) followed by behavioral tests, serum biochemical analysis, and histological examinations of both the dorsal and ventral regions of the hippocampus. In both the 6 M and 9 M cohorts, mice that consumed an HFD exhibited poorer memory performance in the Morris water maze test (MWM) and greater depression- and anxiety-like behavior during the open field test (OFT), sucrose preference test (SPT) and forced swim test (FST) than control mice. Compared with age-matched mice in the CD group, mice in the HFD group showed abnormal hippocampal neuronal morphology, which was particularly evident in the ventral hippocampus. Hippocampal microglia in mice in the HFD group generally had a more activated phenotype evidenced by a smaller microglial territory area and increased cluster of differentiation 68 (CD68, a marker of phagocytic activity) immunoreactivity, while the microglial density in the dentate gyrus (DG) was decreased, indicating microglial decline. The engulfment of postsynaptic density 95 (PSD95, a general postsynaptic marker) puncta by microglia was increased in the HFD groups. Histological analysis of neutral lipids using a fluorescent probe (BODIPY) revealed that the total neutral lipid content in regions of interests (ROIs) and the lipid load in microglia were increased in the HFD group relative to the age-matched CD group. In summary, our results demonstrated that chronic HFD consumption from young adulthood to middle age induced anxiety- and depression-like behavior as well as memory impairment. The negative influence of chronic HFD consumption on behavioral and hippocampal neuroplasticity appears to be linked to a change in microglial phenotype that is accompanied by a remarkable increase in cellular lipid accumulation. These observations highlighting the potential to target lipid metabolism deficits to reduce the risk of HFD-associated emotional dysfunctions.
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Affiliation(s)
- Hong Zhuang
- Department of Physiology, Medical College, Southeast University, Nanjing 210009, China
| | - Xiuting Yao
- Department of Physiology, Medical College, Southeast University, Nanjing 210009, China
| | - Hong Li
- School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Qian Li
- School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Chenxi Yang
- Department of Physiology, Medical College, Southeast University, Nanjing 210009, China
| | - Conghui Wang
- Department of Physiology, Medical College, Southeast University, Nanjing 210009, China
| | - Dan Xu
- School of Public Health, Southeast University, Nanjing 210009
| | - Yu Xiao
- Department of Physiology, Medical College, Southeast University, Nanjing 210009, China
| | - Yuan Gao
- Medical College, Southeast University, Nanjing 210009, China
| | - Jiayi Gao
- Medical College, Southeast University, Nanjing 210009, China
| | - Mingze Bi
- Medical College, Southeast University, Nanjing 210009, China
| | - Rui Liu
- Medical College, Southeast University, Nanjing 210009, China
| | - Gaojun Teng
- Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, China.
| | - Lijie Liu
- Department of Physiology, Medical College, Southeast University, Nanjing 210009, China.
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Onaolapo OJ, Olofinnade AT, Ojo FO, Onaolapo AY. Neuroinflammation and Oxidative Stress in Alzheimer's Disease; Can Nutraceuticals and Functional Foods Come to the Rescue? Antiinflamm Antiallergy Agents Med Chem 2022; 21:75-89. [PMID: 36043770 DOI: 10.2174/1871523021666220815151559] [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: 04/18/2022] [Revised: 06/17/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Alzheimer's disease (AD), the most prevalent form of age-related dementia, is typified by progressive memory loss and spatial awareness with personality changes. The increasing socioeconomic burden associated with AD has made it a focus of extensive research. Ample scientific evidence supports the role of neuroinflammation and oxidative stress in AD pathophysiology, and there is increasing research into the possible role of anti-inflammatory and antioxidative agents as disease modifying therapies. While, the result of numerous preclinical studies has demonstrated the benefits of anti-inflammatory agents, these benefits however have not been replicated in clinical trials, necessitating a further search for more promising anti-inflammatory agents. Current understanding highlights the role of diet in the development of neuroinflammation and oxidative stress, as well as the importance of dietary interventions and lifestyle modifications in mitigating them. The current narrative review examines scientific literature for evidence of the roles (if any) of dietary components, nutraceuticals and functional foods in the prevention or management of AD. It also examines how diet/ dietary components could modulate oxidative stress/inflammatory mediators and pathways that are crucial to the pathogenesis and/or progression of AD.
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Affiliation(s)
- Olakunle J Onaolapo
- Department of Pharmacology, Behavioural Neuroscience Unit, Neuropharmacology Subdivision, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Anthony T Olofinnade
- Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Clinical Sciences, College of Medicine, Lagos State University, Ikeja, Lagos State, Nigeria
| | - Folusho O Ojo
- Department of Anatomy, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Adejoke Y Onaolapo
- Department of Anatomy, Behavioural Neuroscience Unit, Neurobiology Subdivision, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
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