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Zheng Y, Xu S, Liu J, Liu Z. The effects of micro- and nanoplastics on the central nervous system: A new threat to humanity? Toxicology 2024; 504:153799. [PMID: 38608860 DOI: 10.1016/j.tox.2024.153799] [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: 03/10/2024] [Revised: 04/03/2024] [Accepted: 04/07/2024] [Indexed: 04/14/2024]
Abstract
Given the widespread production and use of plastics, poor biodegradability, and inadequate recycling, micro/nanoplastics (MNPs) have caused widespread environmental pollution. As a result, humans inevitably ingest MNPs through various pathways. However, there is still no consensus on whether exposure to MNPs has adverse effects on humans. This article aims to provide a comprehensive overview of the knowledge of MNPs and the potential mechanisms of their impact on the central nervous system. Numerous in vivo and in vitro studies have shown that exposure to MNPs may pass through the blood-brain barrier (BBB) and lead to neurotoxicity through impairments in oxidative and inflammatory balance, neurotransmitter alternation, nerve conduction-related key enzymes, and impact through the gut-brain axis. It is worth noting that MNPs may act as carriers and have more severe effects on the body when co-exposed with other substances. MNPs of smaller sizes cause more severe harm. Despite the scarcity of reports directly relevant to humans, this review brings together a growing body of evidence showing that exposure to MNPs disturbs neurons and has even been found to alter the memory and behavior of organisms. This effect may lead to further potential negative influence on the central nervous system and contribute to the development of other diseases such as central nervous system inflammation and Parkinson 's-like neurodegenerative disorders. There is a need further to investigate the threat of MNPs to human health.
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Affiliation(s)
- Yanxu Zheng
- Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Shengchao Xu
- Department of Neurosurgery, Xiangya Hospital, 87th Xiangya Road, Changsha, Hunan 410008, PR China
| | - Jingyu Liu
- Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Zhixiong Liu
- Department of Neurosurgery, Xiangya Hospital, 87th Xiangya Road, Changsha, Hunan 410008, PR China; National Clinical Research Center for Geriatric Disorders, Changsha, Hunan 410013, PR China.
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2
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Davis E, Lloyd AF. The proteomic landscape of microglia in health and disease. Front Cell Neurosci 2024; 18:1379717. [PMID: 38560294 PMCID: PMC10978577 DOI: 10.3389/fncel.2024.1379717] [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: 01/31/2024] [Accepted: 03/01/2024] [Indexed: 04/04/2024] Open
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) and as such play crucial roles in regulating brain homeostasis. Their presence in neurodegenerative diseases is known, with neurodegeneration-associated risk genes heavily expressed in microglia, highlighting their importance in contributing to disease pathogenesis. Transcriptomics studies have uncovered the heterogeneous landscape of microglia in health and disease, identifying important disease-associated signatures such as DAM, and insight into both the regional and temporal diversity of microglia phenotypes. Quantitative mass spectrometry methods are ever increasing in the field of neurodegeneration, utilised as ways to identify disease biomarkers and to gain deeper understanding of disease pathology. Proteins are the main mechanistic indicators of cellular function, yet discordance between transcript and proteomic findings has highlighted the need for in-depth proteomic phenotypic and functional analysis to fully understand disease kinetics at the cellular and molecular level. This review details the current progress of using proteomics to define microglia biology, the relationship between gene and protein expression in microglia, and the future of proteomics and emerging methods aiming to resolve heterogeneous cell landscapes.
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Affiliation(s)
- Emma Davis
- The Francis Crick Institute, London, United Kingdom
- UK Dementia Research Institute at UCL, University College London, London, United Kingdom
| | - Amy F. Lloyd
- Cell Signalling and Immunology, University of Dundee, Dundee, United Kingdom
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3
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Fan H, Zhang M, Wen J, Wang S, Yuan M, Sun H, Shu L, Yang X, Pu Y, Cai Z. Microglia in brain aging: An overview of recent basic science and clinical research developments. J Biomed Res 2024; 38:122-136. [PMID: 38403286 PMCID: PMC11001587 DOI: 10.7555/jbr.37.20220220] [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: 10/05/2022] [Revised: 12/25/2022] [Accepted: 01/12/2023] [Indexed: 02/27/2024] Open
Abstract
Aging is characterized by progressive degeneration of tissues and organs, and it is positively associated with an increased mortality rate. The brain, as one of the most significantly affected organs, experiences age-related changes, including abnormal neuronal activity, dysfunctional calcium homeostasis, dysregulated mitochondrial function, and increased levels of reactive oxygen species. These changes collectively contribute to cognitive deterioration. Aging is also a key risk factor for neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. For many years, neurodegenerative disease investigations have primarily focused on neurons, with less attention given to microglial cells. However, recently, microglial homeostasis has emerged as an important mediator in neurological disease pathogenesis. Here, we provide an overview of brain aging from the perspective of the microglia. In doing so, we present the current knowledge on the correlation between brain aging and the microglia, summarize recent progress of investigations about the microglia in normal aging, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and then discuss the correlation between the senescent microglia and the brain, which will culminate with a presentation of the molecular complexity involved in the microglia in brain aging with suggestions for healthy aging.
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Affiliation(s)
- Haixia Fan
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
- Department of Neurology, the First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Minheng Zhang
- Department of Gerontology, the First People's Hospital of Jinzhong, Jinzhong, Shanxi 030009, China
| | - Jie Wen
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Shengyuan Wang
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Minghao Yuan
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Houchao Sun
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Liu Shu
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Xu Yang
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Yinshuang Pu
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
| | - Zhiyou Cai
- Chongqing Medical University, Chongqing 400042, China
- Department of Neurology, Chongqing General Hospital, Chongqing 400013, China
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing 400013, China
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4
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Luo H, Liu N, Lin C. Dopamine enhances recovery after traumatic brain injury through ubiquitylation and autophagic degradation of RIPK1. Cell Commun Signal 2024; 22:134. [PMID: 38374093 PMCID: PMC10875858 DOI: 10.1186/s12964-024-01515-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: 10/22/2023] [Accepted: 02/05/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Although the neurotransmitter dopamine (DA) plays a crucial pathophysiologic role after traumatic brain injury (TBI), its function and specific underlying mechanisms of action remain unclear. METHODS Adult male mice underwent controlled cortical impact (CCI). We administered DA intraperitoneally to mice for 14 consecutive days, starting 8 h before CCI. On day 3 after brain injury, cortical lesion volume and brain water content were measured. On days 7-13, behavioral tests were performed. RESULTS Herein we report that DA inhibits neural death after injury, which is mediated via the dopamine D1 receptor (DRD1). Our results also showed that DRD1 signaling promotes RIPK1 ubiquitination via the E3 ubiquitin ligase Chip and then degradation through autophagy. Importantly, in vivo data revealed that DRD1 signaling prevented neural death, suppressed neuroinflammation, and restored many TBI-related functional sequelae. CONCLUSIONS These data reveal a novel mechanism involving dopamine, and suggest that DRD1 activation positively regulates Chip-mediated ubiquitylation of RIPK1-leading to its autophagic degradation.
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Affiliation(s)
- Hui Luo
- Department of Neurosurgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Ning Liu
- Department of Neurosurgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Chao Lin
- Department of Neurosurgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
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5
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Gao X, Lin C, Feng Y, You Y, Jin Z, Li M, Zhou Y, Chen K. Akkermansia muciniphila-derived small extracellular vesicles attenuate intestinal ischemia-reperfusion-induced postoperative cognitive dysfunction by suppressing microglia activation via the TLR2/4 signaling. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119630. [PMID: 37967793 DOI: 10.1016/j.bbamcr.2023.119630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/17/2023]
Abstract
Akkermansia muciniphila (AKK) bacteria improve the functions of theere intestinal and blood-brain barriers (BBB) via their extracellular vesicles (AmEvs). However, their role in postoperative cognitive dysfunction (POCD) and its underlying mechanisms remain unclear. To investigate, we used C57BL/6 J mice divided into five groups: Sham, POCD, POCD+Akk, POCD+Evs, and POCD+Evs + PLX5622. POCD was induced through intestinal ischemia-reperfusion (I/R). The mice's cognitive function was assessed using behavioral tests, and possible mechanisms were explored by examining gut and BBB permeability, inflammation, and microglial function. Toll-like receptor (TLR) 2/4 pathway-related proteins were also investigated both in vitro and in vivo. PLX5622 chow was employed to eliminate microglial cells. Our findings revealed a negative correlation between AKK abundance and POCD symptoms. Supplementation with either AKK or AmEvs improved cognitive function, improved the performance of the intestinal barrier and BBB, and decreased inflammation and microglial activation in POCD mice compared to controls. Moreover, AmEvs treatment inhibited TLR2/4 signaling in the brains of POCD mice and LPS-treated microglial cells. In microglial-ablated POCD mice, however, AmEvs failed to protect BBB integrity. Overall, AmEvs is a potential therapeutic strategy for managing POCD by enhancing gut and BBB integrity and inhibiting microglial-mediated TLR2/4 signaling.
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Affiliation(s)
- Xiang Gao
- Department of Anesthesiology, Fujian Maternity and Child Health Hospital, Fuzhou, 350000, China; College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, 350000, China
| | - Chuantao Lin
- Department of Anesthesiology, Fujian Maternity and Child Health Hospital, Fuzhou, 350000, China; College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, 350000, China
| | - Yebin Feng
- Department of Science and Education, Fujian Maternity and Child Health Hospital, Fuzhou, 350000, China; College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, 350000, China
| | - Yi You
- Department of Anesthesiology, Fujian Maternity and Child Health Hospital, Fuzhou, 350000, China; College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, 350000, China
| | - Zhe Jin
- Department of Anesthesiology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Mengyun Li
- Department of Anesthesiology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Yufeng Zhou
- Department of Anesthesiology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Kai Chen
- Department of Anesthesiology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
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6
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Castro R, Lopes M, De Biase L, Valdez G. Aging spinal cord microglia become phenotypically heterogeneous and preferentially target motor neurons and their synapses. Glia 2024; 72:206-221. [PMID: 37737058 PMCID: PMC10773989 DOI: 10.1002/glia.24470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/07/2023] [Accepted: 09/03/2023] [Indexed: 09/23/2023]
Abstract
Microglia have been found to acquire unique region-dependent deleterious features with age and diseases that contribute to neuronal dysfunction and degeneration in the brain. However, it remains unknown whether microglia exhibit similar phenotypic heterogeneity in the spinal cord. Here, we performed a regional analysis of spinal cord microglia in 3-, 16-, 23-, and 30-month-old mice. Using light and electron microscopy, we discovered that spinal cord microglia acquire an increasingly activated phenotype during the course of aging regardless of regional location. However, aging causes microglia in the ventral but not dorsal horn to lose their spatial organization. Aged ventral horn microglia also aggregate around the somata of motor neurons and increase their contacts with motor synapses, which have been shown to be lost with age. These findings suggest that microglia may affect the ability of motor neurons to receive and relay motor commands during aging. To generate additional insights about aging spinal cord microglia, we performed RNA-sequencing on FACS-isolated microglia from 3-, 18-, 22-, and 29-month-old mice. We found that spinal cord microglia acquire a similar transcriptional identity as those in the brain during aging that includes altered expression of genes with roles in microglia-neuron interactions and inflammation. By 29 months of age, spinal cord microglia exhibit additional and unique transcriptional changes known and predicted to cause senescence and to alter lysosomal and ribosomal regulation. Altogether, this work provides the foundation to target microglia to ameliorate aged-related changes in the spinal cord, and particularly on the motor circuit.
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Affiliation(s)
- Ryan Castro
- Neuroscience Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Mikayla Lopes
- Molecular Biology, Cell Biology & Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Lindsay De Biase
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, Rhode Island, USA
- Department of Neurology, Warren Alpert Medical School of Medicine, Brown University, Providence, USA
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7
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Glotfelty EJ, Hsueh SC, Claybourne Q, Bedolla A, Kopp KO, Wallace T, Zheng B, Luo Y, Karlsson TE, McDevitt RA, Olson L, Greig NH. Microglial Nogo delays recovery following traumatic brain injury in mice. Glia 2023; 71:2473-2494. [PMID: 37401784 PMCID: PMC10528455 DOI: 10.1002/glia.24436] [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: 05/22/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/05/2023]
Abstract
Nogo-A, B, and C are well described members of the reticulon family of proteins, most well known for their negative regulatory effects on central nervous system (CNS) neurite outgrowth and repair following injury. Recent research indicates a relationship between Nogo-proteins and inflammation. Microglia, the brain's immune cells and inflammation-competent compartment, express Nogo protein, although specific roles of the Nogo in these cells is understudied. To examine inflammation-related effects of Nogo, we generated a microglial-specific inducible Nogo KO (MinoKO) mouse and challenged the mouse with a controlled cortical impact (CCI) traumatic brain injury (TBI). Histological analysis shows no difference in brain lesion sizes between MinoKO-CCI and Control-CCI mice, although MinoKO-CCI mice do not exhibit the levels of ipsilateral lateral ventricle enlargement as injury matched controls. Microglial Nogo-KO results in decreased lateral ventricle enlargement, microglial and astrocyte immunoreactivity, and increased microglial morphological complexity compared to injury matched controls, suggesting decreased tissue inflammation. Behaviorally, healthy MinoKO mice do not differ from control mice, but automated tracking of movement around the home cage and stereotypic behavior, such as grooming and eating (termed cage "activation"), following CCI is significantly elevated. Asymmetrical motor function, a deficit typical of unilaterally brain lesioned rodents, was not detected in CCI injured MinoKO mice, while the phenomenon was present in CCI injured controls 1-week post-injury. Overall, our studies show microglial Nogo as a negative regulator of recovery following brain injury. To date, this is the first evaluation of the roles microglial specific Nogo in a rodent injury model.
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Affiliation(s)
- Elliot J. Glotfelty
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program National Institute on Aging, NIH, Baltimore, MD 21224, USA
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Shih-Chang Hsueh
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Quia Claybourne
- Comparative Medicine Section, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Alicia Bedolla
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Katherine O. Kopp
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Tonya Wallace
- Flow Cytometry Unit, National Institute on Aging, Baltimore, MD, USA
| | - Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Yu Luo
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | | | - Ross A. McDevitt
- Comparative Medicine Section, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Lars Olson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Nigel H. Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program National Institute on Aging, NIH, Baltimore, MD 21224, USA
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8
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Itoh N, Itoh Y, Meyer CE, Suen TT, Cortez-Delgado D, Rivera Lomeli M, Wendin S, Somepalli SS, Golden LC, MacKenzie-Graham A, Voskuhl RR. Estrogen receptor beta in astrocytes modulates cognitive function in mid-age female mice. Nat Commun 2023; 14:6044. [PMID: 37758709 PMCID: PMC10533869 DOI: 10.1038/s41467-023-41723-7] [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: 09/21/2021] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Menopause is associated with cognitive deficits and brain atrophy, but the brain region and cell-specific mechanisms are not fully understood. Here, we identify a sex hormone by age interaction whereby loss of ovarian hormones in female mice at midlife, but not young age, induced hippocampal-dependent cognitive impairment, dorsal hippocampal atrophy, and astrocyte and microglia activation with synaptic loss. Selective deletion of estrogen receptor beta (ERβ) in astrocytes, but not neurons, in gonadally intact female mice induced the same brain effects. RNA sequencing and pathway analyses of gene expression in hippocampal astrocytes from midlife female astrocyte-ERβ conditional knock out (cKO) mice revealed Gluconeogenesis I and Glycolysis I as the most differentially expressed pathways. Enolase 1 gene expression was increased in hippocampi from both astrocyte-ERβ cKO female mice at midlife and from postmenopausal women. Gain of function studies showed that ERβ ligand treatment of midlife female mice reversed dorsal hippocampal neuropathology.
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Affiliation(s)
- Noriko Itoh
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Yuichiro Itoh
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Cassandra E Meyer
- Ahmanson-Lovelace Brain Mapping Center, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Timothy Takazo Suen
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Diego Cortez-Delgado
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | | | - Sophia Wendin
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sri Sanjana Somepalli
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Lisa C Golden
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Allan MacKenzie-Graham
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Ahmanson-Lovelace Brain Mapping Center, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Rhonda R Voskuhl
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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9
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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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10
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Ravenhill SM, Evans AH, Crewther SG. Escalating Bi-Directional Feedback Loops between Proinflammatory Microglia and Mitochondria in Ageing and Post-Diagnosis of Parkinson's Disease. Antioxidants (Basel) 2023; 12:antiox12051117. [PMID: 37237983 DOI: 10.3390/antiox12051117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Parkinson's disease (PD) is a chronic and progressive age-related neurodegenerative disease affecting up to 3% of the global population over 65 years of age. Currently, the underlying physiological aetiology of PD is unknown. However, the diagnosed disorder shares many common non-motor symptoms associated with ageing-related neurodegenerative disease progression, such as neuroinflammation, microglial activation, neuronal mitochondrial impairment, and chronic autonomic nervous system dysfunction. Clinical PD has been linked to many interrelated biological and molecular processes, such as escalating proinflammatory immune responses, mitochondrial impairment, lower adenosine triphosphate (ATP) availability, increasing release of neurotoxic reactive oxygen species (ROS), impaired blood brain barrier integrity, chronic activation of microglia, and damage to dopaminergic neurons consistently associated with motor and cognitive decline. Prodromal PD has also been associated with orthostatic hypotension and many other age-related impairments, such as sleep disruption, impaired gut microbiome, and constipation. Thus, this review aimed to present evidence linking mitochondrial dysfunction, including elevated oxidative stress, ROS, and impaired cellular energy production, with the overactivation and escalation of a microglial-mediated proinflammatory immune response as naturally occurring and damaging interlinked bidirectional and self-perpetuating cycles that share common pathological processes in ageing and PD. We propose that both chronic inflammation, microglial activation, and neuronal mitochondrial impairment should be considered as concurrently influencing each other along a continuum rather than as separate and isolated linear metabolic events that affect specific aspects of neural processing and brain function.
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Affiliation(s)
| | - Andrew Howard Evans
- Department of Medicine, The Walter and Eliza Hall Institute of Medical Research, Melbourne 3052, Australia
- Epworth Hospital, Richmond 3121, Australia
- Department of Neurology, Royal Melbourne Hospital, Melbourne 3050, Australia
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Carlson ER, Guerin SP, Nixon K, Fonken LK. The neuroimmune system - Where aging and excess alcohol intersect. Alcohol 2023; 107:153-167. [PMID: 36150610 PMCID: PMC10023388 DOI: 10.1016/j.alcohol.2022.08.009] [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: 06/07/2022] [Revised: 08/21/2022] [Accepted: 08/31/2022] [Indexed: 01/05/2023]
Abstract
As the percentage of the global population over age 65 grows, and with it a subpopulation of individuals with alcohol use disorder (AUD), understanding the effect of alcohol on the aged brain is of utmost importance. Neuroinflammation is implicated in both natural aging as well as alcohol use, and its role in alterations to brain morphology and function may be exacerbated in aging individuals who drink alcohol to excess. The neuroimmune response to alcohol in aging is complex. The few studies investigating this issue have reported heightened basal activity and either hypo- or hyper-reactivity to an alcohol challenge. This review of preclinical research will first introduce key players of the immune system, then explore changes in neuroimmune function with aging or alcohol alone, with discussion of vulnerable brain regions, changes in cytokines, and varied reactions of microglia and astrocytes. We will then consider different levels of alcohol exposure, relevant animal models of AUD, and neuroimmune activation by alcohol across the lifespan. By identifying key findings, challenges, and targets for future research, we hope to bring more attention and resources to this underexplored area of inquiry.
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Affiliation(s)
- Erika R Carlson
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, United States
| | - Steven P Guerin
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, United States
| | - Kimberly Nixon
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, United States
| | - Laura K Fonken
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, United States.
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Xu J, Zhang L, Li M, He X, Luo J, Wu R, Hong Z, Zheng H, Hu X. TREM2 mediates physical exercise-promoted neural functional recovery in rats with ischemic stroke via microglia-promoted white matter repair. J Neuroinflammation 2023; 20:50. [PMID: 36829205 PMCID: PMC9960657 DOI: 10.1186/s12974-023-02741-w] [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: 12/28/2021] [Accepted: 02/17/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND The repair of white matter injury is of significant importance for functional recovery after ischemic stroke, and the up-regulation of triggering receptors expressed on myeloid cells 2 (TREM2) after ischemic stroke is neuroprotective and implicated in remyelination. However, the lack of effective therapies calls for the need to investigate the regenerative process of remyelination and the role of rehabilitation therapy. This study sought to investigate whether and how moderate physical exercise (PE) promotes oligodendrogenesis and remyelination in rats with transient middle cerebral artery occlusion (tMCAO). METHODS Male Sprague-Dawley rats (weighing 250-280 g) were subjected to tMCAO. AAV-shRNA was injected into the lateral ventricle to silence the Trem2 gene before the operation. The rats in the physical exercise group started electric running cage training at 48 h after the operation. The Morris water maze and novel object recognition test were used to evaluate cognitive function. Luxol fast blue staining, diffusion tensor imaging, and electron microscopy were used to observe myelin injury and repair. Immunofluorescence staining was applied to observe the proliferation and differentiation of oligodendrocyte precursor cells (OPCs). Expression of key molecules were detected using immunofluorescence staining, quantitative real-time polymerase chain reaction, Western blotting, and Enzyme-linked immunosorbent assay, respectively. RESULTS PE exerted neuroprotective efects by modulating microglial state, promoting remyelination and recovery of neurological function of rats over 35 d after stroke, while silencing Trem2 expression in rats suppressed the aforementioned effects promoted by PE. In addition, by leveraging the activin-A neutralizing antibody, we found a direct beneficial effect of PE on microglia-derived activin-A and its subsequent role on oligodendrocyte differentiation and remyelination mediated by the activin-A/Acvr axis. CONCLUSIONS The present study reveals a novel regenerative role of PE in white matter injury after stroke, which is mediated by upregulation of TREM2 and microglia-derived factor for oligodendrocytes regeneration. PE is an effective therapeutic approach for improving white matter integrity and alleviating neurological function deficits after ischemic stroke.
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Affiliation(s)
- Jinghui Xu
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Liying Zhang
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Mingyue Li
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Xiaofei He
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Jing Luo
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Rui Wu
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Zhongqiu Hong
- grid.12981.330000 0001 2360 039XDepartment of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China
| | - Haiqing Zheng
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China.
| | - Xiquan Hu
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, China.
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Pexidartinib (PLX3397) through restoring hippocampal synaptic plasticity ameliorates social isolation-induced mood disorders. Int Immunopharmacol 2022; 113:109436. [PMID: 36395673 PMCID: PMC9661988 DOI: 10.1016/j.intimp.2022.109436] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/01/2022] [Accepted: 11/04/2022] [Indexed: 11/16/2022]
Abstract
Social behavior is essential for the well-being and survival of individuals. However, social isolation is a serious public health issue, especially during the COVID-19 pandemic, affecting a significant number of people worldwide, and can lead to serious psychological crises. Microglia, innate immune cells in the brain, are strongly implicated in the development of psychiatry. Although many microglial inhibitors have been used to treat depression, there is no literature report on pexidartinib (PLX3397) and social isolation. Herein, we adopted PLX3397 to investigate the role of microglia in the modulation of social isolation. Our results found that social isolation during adolescence caused depressive-like, but not anxiety-like behavior in mice in adulthood, with enhanced expression of the microglial marker Iba1 in the hippocampus. In addition, treatment with PLX3397 reduced the expression of the microglial marker Iba1, decreased the mRNA expression of IL-1β, increased the mRNA expression of Arg1, elevated the protein levels of DCX and GluR1 and restored the dendritic spine branches and density, ultimately mitigating depressive-like behavior in mice. These findings suggest that inhibition of microglia in the hippocampus could ameliorate mood disorders in mice, providing a new perspective for the treatment of psychiatric disorders such as depression.
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