1
|
Wilson EN, Wang C, Swarovski MS, Zera KA, Ennerfelt HE, Wang Q, Chaney A, Gauba E, Ramos Benitez JA, Le Guen Y, Minhas PS, Panchal M, Tan YJ, Blacher E, A Iweka C, Cropper H, Jain P, Liu Q, Mehta SS, Zuckerman AJ, Xin M, Umans J, Huang J, Durairaj AS, Serrano GE, Beach TG, Greicius MD, James ML, Buckwalter MS, McReynolds MR, Rabinowitz JD, Andreasson KI. TREM1 disrupts myeloid bioenergetics and cognitive function in aging and Alzheimer disease mouse models. Nat Neurosci 2024; 27:873-885. [PMID: 38539014 DOI: 10.1038/s41593-024-01610-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 02/22/2024] [Indexed: 04/21/2024]
Abstract
Human genetics implicate defective myeloid responses in the development of late-onset Alzheimer disease. A decline in peripheral and brain myeloid metabolism, triggering maladaptive immune responses, is a feature of aging. The role of TREM1, a pro-inflammatory factor, in neurodegenerative diseases is unclear. Here we show that Trem1 deficiency prevents age-dependent changes in myeloid metabolism, inflammation and hippocampal memory function in mice. Trem1 deficiency rescues age-associated declines in ribose 5-phosphate. In vitro, Trem1-deficient microglia are resistant to amyloid-β42 oligomer-induced bioenergetic changes, suggesting that amyloid-β42 oligomer stimulation disrupts homeostatic microglial metabolism and immune function via TREM1. In the 5XFAD mouse model, Trem1 haploinsufficiency prevents spatial memory loss, preserves homeostatic microglial morphology, and reduces neuritic dystrophy and changes in the disease-associated microglial transcriptomic signature. In aging APPSwe mice, Trem1 deficiency prevents hippocampal memory decline while restoring synaptic mitochondrial function and cerebral glucose uptake. In postmortem Alzheimer disease brain, TREM1 colocalizes with Iba1+ cells around amyloid plaques and its expression is associated with Alzheimer disease clinical and neuropathological severity. Our results suggest that TREM1 promotes cognitive decline in aging and in the context of amyloid pathology.
Collapse
Affiliation(s)
- Edward N Wilson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
| | - Congcong Wang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle S Swarovski
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Kristy A Zera
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Hannah E Ennerfelt
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Qian Wang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Aisling Chaney
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Esha Gauba
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Javier A Ramos Benitez
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Yann Le Guen
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Paras S Minhas
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Maharshi Panchal
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Yuting J Tan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Eran Blacher
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Chinyere A Iweka
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Haley Cropper
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Poorva Jain
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Qingkun Liu
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Swapnil S Mehta
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Abigail J Zuckerman
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Matthew Xin
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Jacob Umans
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Jolie Huang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Aarooran S Durairaj
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Geidy E Serrano
- Civin Laboratory for Neuropathology, Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Thomas G Beach
- Civin Laboratory for Neuropathology, Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Michael D Greicius
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
| | - Michelle L James
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Marion S Buckwalter
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Melanie R McReynolds
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Department of Biochemistry and Molecular Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Katrin I Andreasson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
| |
Collapse
|
2
|
Samuels JD, Moore KA, Ennerfelt HE, Johnson AM, Walsh AE, Price RJ, Lukens JR. The Alzheimer's disease risk factor INPP5D restricts neuroprotective microglial responses in amyloid beta-mediated pathology. Alzheimers Dement 2023; 19:4908-4921. [PMID: 37061460 PMCID: PMC10576836 DOI: 10.1002/alz.13089] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/07/2023] [Accepted: 02/12/2023] [Indexed: 04/17/2023]
Abstract
INTRODUCTION Mutations in INPP5D, which encodes for the SH2-domain-containing inositol phosphatase SHIP-1, have recently been linked to an increased risk of developing late-onset Alzheimer's disease. While INPP5D expression is almost exclusively restricted to microglia in the brain, little is known regarding how SHIP-1 affects neurobiology or neurodegenerative disease pathogenesis. METHODS We generated and investigated 5xFAD Inpp5dfl/fl Cx3cr1Ert2Cre mice to ascertain the function of microglial SHIP-1 signaling in response to amyloid beta (Aβ)-mediated pathology. RESULTS SHIP-1 deletion in microglia led to substantially enhanced recruitment of microglia to Aβ plaques, altered microglial gene expression, and marked improvements in neuronal health. Further, SHIP-1 loss enhanced microglial plaque containment and Aβ engulfment when compared to microglia from Cre-negative 5xFAD Inpp5dfl/fl littermate controls. DISCUSSION These results define SHIP-1 as a pivotal regulator of microglial responses during Aβ-driven neurological disease and suggest that targeting SHIP-1 may offer a promising strategy to treat Alzheimer's disease. HIGHLIGHTS Inpp5d deficiency in microglia increases plaque-associated microglia numbers. Loss of Inpp5d induces activation and phagocytosis transcriptional pathways. Plaque encapsulation and engulfment by microglia are enhanced with Inpp5d deletion. Genetic ablation of Inpp5d protects against plaque-induced neuronal dystrophy.
Collapse
Affiliation(s)
- Joshua D. Samuels
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Katelyn A. Moore
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
| | - Hannah E. Ennerfelt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
| | - Alexis M. Johnson
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
- Brain Immunology and Glia Training Program, UVA, Charlottesville, VA 22908, USA
| | - Adeline E. Walsh
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Molecular Physiology and Biological Physics Graduate Program, UVA, Charlottesville, VA 22908, USA
- Biotechnology Training Program, UVA, Charlottesville, VA 22908, USA
| | - Richard J. Price
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
- Biotechnology Training Program, UVA, Charlottesville, VA 22908, USA
| | - John R. Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
- Brain Immunology and Glia Training Program, UVA, Charlottesville, VA 22908, USA
- Molecular Physiology and Biological Physics Graduate Program, UVA, Charlottesville, VA 22908, USA
- Biotechnology Training Program, UVA, Charlottesville, VA 22908, USA
| |
Collapse
|
3
|
Bolte AC, Shapiro DA, Dutta AB, Ma WF, Bruch KR, Kovacs MA, Royo Marco A, Ennerfelt HE, Lukens JR. The meningeal transcriptional response to traumatic brain injury and aging. eLife 2023; 12:81154. [PMID: 36594818 PMCID: PMC9810333 DOI: 10.7554/elife.81154] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/14/2022] [Indexed: 12/31/2022] Open
Abstract
Emerging evidence suggests that the meningeal compartment plays instrumental roles in various neurological disorders, however, we still lack fundamental knowledge about meningeal biology. Here, we utilized high-throughput RNA sequencing (RNA-seq) techniques to investigate the transcriptional response of the meninges to traumatic brain injury (TBI) and aging in the sub-acute and chronic time frames. Using single-cell RNA sequencing (scRNA-seq), we first explored how mild TBI affects the cellular and transcriptional landscape in the meninges in young mice at one-week post-injury. Then, using bulk RNA-seq, we assessed the differential long-term outcomes between young and aged mice following TBI. In our scRNA-seq studies, we highlight injury-related changes in differential gene expression seen in major meningeal cell populations including macrophages, fibroblasts, and adaptive immune cells. We found that TBI leads to an upregulation of type I interferon (IFN) signature genes in macrophages and a controlled upregulation of inflammatory-related genes in the fibroblast and adaptive immune cell populations. For reasons that remain poorly understood, even mild injuries in the elderly can lead to cognitive decline and devastating neuropathology. To better understand the differential outcomes between the young and the elderly following brain injury, we performed bulk RNA-seq on young and aged meninges 1.5 months after TBI. Notably, we found that aging alone induced upregulation of meningeal genes involved in antibody production by B cells and type I IFN signaling. Following injury, the meningeal transcriptome had largely returned to its pre-injury signature in young mice. In stark contrast, aged TBI mice still exhibited upregulation of immune-related genes and downregulation of genes involved in extracellular matrix remodeling. Overall, these findings illustrate the dynamic transcriptional response of the meninges to mild head trauma in youth and aging.
Collapse
Affiliation(s)
- Ashley C Bolte
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of MedicineCharlottesvilleUnited States,Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Immunology Training Program, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Daniel A Shapiro
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States
| | - Arun B Dutta
- Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Wei Feng Ma
- Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Center for Public Health Genomics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Katherine R Bruch
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States
| | - Michael A Kovacs
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of MedicineCharlottesvilleUnited States,Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Immunology Training Program, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Ana Royo Marco
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Hannah E Ennerfelt
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States
| | - John R Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Immunology Training Program, University of Virginia School of MedicineCharlottesvilleUnited States
| |
Collapse
|
4
|
Bolte AC, Dutta AB, Hurt ME, Smirnov I, Kovacs MA, McKee CA, Ennerfelt HE, Shapiro D, Nguyen BH, Frost EL, Lammert CR, Kipnis J, Lukens JR. Meningeal lymphatic dysfunction exacerbates traumatic brain injury pathogenesis. Nat Commun 2020; 11:4524. [PMID: 32913280 PMCID: PMC7483525 DOI: 10.1038/s41467-020-18113-4] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 08/06/2020] [Indexed: 01/12/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading global cause of death and disability. Here we demonstrate in an experimental mouse model of TBI that mild forms of brain trauma cause severe deficits in meningeal lymphatic drainage that begin within hours and last out to at least one month post-injury. To investigate a mechanism underlying impaired lymphatic function in TBI, we examined how increased intracranial pressure (ICP) influences the meningeal lymphatics. We demonstrate that increased ICP can contribute to meningeal lymphatic dysfunction. Moreover, we show that pre-existing lymphatic dysfunction before TBI leads to increased neuroinflammation and negative cognitive outcomes. Finally, we report that rejuvenation of meningeal lymphatic drainage function in aged mice can ameliorate TBI-induced gliosis. These findings provide insights into both the causes and consequences of meningeal lymphatic dysfunction in TBI and suggest that therapeutics targeting the meningeal lymphatic system may offer strategies to treat TBI.
Collapse
Affiliation(s)
- Ashley C Bolte
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA
- Immunology Training Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Arun B Dutta
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Mariah E Hurt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Igor Smirnov
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Michael A Kovacs
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA
- Immunology Training Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Celia A McKee
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Hannah E Ennerfelt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Daniel Shapiro
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Bao H Nguyen
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Elizabeth L Frost
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Catherine R Lammert
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - John R Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA.
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA.
- Immunology Training Program, University of Virginia, Charlottesville, VA, 22908, USA.
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA.
| |
Collapse
|
5
|
Abstract
The amyloid hypothesis has dominated Alzheimer's disease (AD) research for almost 30 years. This hypothesis hinges on the predominant clinical role of the amyloid beta (Aβ) peptide in propagating neurofibrillary tangles (NFTs) and eventual cognitive impairment in AD. Recent research in the AD field has identified the brain-resident macrophages, known as microglia, and their receptors as integral regulators of both the initiation and propagation of inflammation, Aβ accumulation, neuronal loss, and memory decline in AD. Emerging studies have also begun to reveal critical roles for distinct innate immune pathways in AD pathogenesis, which has led to great interest in harnessing the innate immune response as a therapeutic strategy to treat AD. In this review, we will highlight recent advancements in our understanding of innate immunity and inflammation in AD onset and progression. Additionally, there has been mounting evidence suggesting pivotal contributions of environmental factors and lifestyle choices in AD pathogenesis. Therefore, we will also discuss recent findings, suggesting that many of these AD risk factors influence AD progression via modulation of microglia and immune responses.
Collapse
Affiliation(s)
- Hannah E. Ennerfelt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - John R. Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| |
Collapse
|
6
|
Bolte AC, Hurt ME, Smirnov I, Dutta AB, Kovacs MA, McKee CA, Natale N, Ennerfelt HE, Nguyen BH, Frost EL, Lammert CE, Kipnis J, Lukens JR. Meningeal lymphatic dysfunction exacerbates traumatic brain injury pathogenesis. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.64.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Traumatic brain injury (TBI) has emerged as a leading cause of death and disability. Despite being a growing medical issue, the biological factors that promote central nervous system (CNS) pathology and neurological dysfunction following TBI remain poorly characterized. Recently, the meningeal lymphatic system was identified as a critical mediator of drainage from the CNS. In comparison to other peripheral organs, our understanding of how defects in lymphatic drainage from the CNS contribute to disease is limited. It is still unknown how TBI impacts meningeal lymphatic function and whether disruptions in this drainage pathway are involved in driving TBI pathogenesis. Here we demonstrate that even mild forms of brain trauma cause severe deficits in meningeal lymphatic drainage that can last out to at least two weeks post-injury. To investigate a mechanism behind impaired lymphatic function in TBI, we examined how increased intracranial pressure (ICP) influences the meningeal lymphatics, as increased ICP commonly occurs in TBI. We demonstrate that increased ICP is capable of provoking meningeal lymphatic dysfunction. Moreover, we show that pre-existing lymphatic dysfunction mediated by targeted photoablation before TBI leads to increased neuroinflammation and cognitive deficits. These findings provide new insights into both the causes and consequences of meningeal lymphatic dysfunction in TBI and suggest that therapeutics targeting the meningeal lymphatic system may offer strategies to treat TBI.
Collapse
|