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Da Mesquita S, Rua R. Brain border-associated macrophages: common denominators in infection, aging, and Alzheimer's disease? Trends Immunol 2024; 45:346-357. [PMID: 38632001 PMCID: PMC11088519 DOI: 10.1016/j.it.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/19/2024]
Abstract
Mammalian brain border-associated macrophages (BAMs) are strategically positioned to support vital properties and processes: for example, the composition of the brain's perivascular extracellular matrix and cerebrospinal fluid flow via the glymphatic pathway. BAMs also effectively restrict the spread of infectious microbes into the brain. However, while fighting infections, BAMs sustain long-term transcriptomic changes and can be replaced by inflammatory monocytes, potentially leading to a gradual loss of their beneficial homeostatic functions. We hypothesize that by expediting the deterioration of BAMs, multiple infection episodes might be associated with accelerated brain aging and the putative development of neurodegenerative diseases. Our viewpoint is supported by recent studies suggesting that rejuvenating aged BAMs, and counterbalancing their detrimental inflammatory signatures during infections, might hold promise in treating aging-related neurological disorders, including Alzheimer's disease (AD).
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Affiliation(s)
| | - Rejane Rua
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.
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Min H, O’Neil SM, Xu L, Moseman EA, Kurtzberg J, Filiano AJ. Mural cells interact with macrophages in the dura mater to regulate CNS immune surveillance. J Exp Med 2024; 221:e20230326. [PMID: 38193859 PMCID: PMC10783178 DOI: 10.1084/jem.20230326] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 09/07/2023] [Accepted: 12/13/2023] [Indexed: 01/10/2024] Open
Abstract
The central nervous system (CNS) tightly regulates access of circulating immune cells. Immunosurveillance is therefore managed in the meninges at the borders of the CNS. Here, we demonstrated that mural cells, which include pericytes and smooth muscle cells, decreased coverage around blood vessels in the dura, the outermost layer of the meninges, and upregulated gene pathways involved in leukocyte migration in presymptomatic experimental autoimmune encephalomyelitis (EAE). Partially depleting mural cells promoted the trafficking of CNS antigen-specific T cells to the dura in a process that depended on resident antigen-presenting cells, thereby increasing susceptibility to passive EAE. Mechanistically, mural cells physically contacted macrophages in the dura and transferred cytoplasmic components, including processing bodies (RNA granules shown to reprogram transcriptomes), which were critical to suppress antigen-dependent T helper (TH) cell activation and TH17 differentiation. Our study revealed a mechanism by which mural cell-macrophage interactions regulate the trafficking of CNS antigen-specific T cells to the dura.
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Affiliation(s)
- Hyunjung Min
- Marcus Center for Cellular Cures, Duke University School of Medicine, Durham, NC, USA
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC, USA
| | - Shane M. O’Neil
- Marcus Center for Cellular Cures, Duke University School of Medicine, Durham, NC, USA
| | - Li Xu
- Marcus Center for Cellular Cures, Duke University School of Medicine, Durham, NC, USA
| | - E. Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - Joanne Kurtzberg
- Marcus Center for Cellular Cures, Duke University School of Medicine, Durham, NC, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Anthony J. Filiano
- Marcus Center for Cellular Cures, Duke University School of Medicine, Durham, NC, USA
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC, USA
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
- Department of Pathology, Duke University School of Medicine, Durham, NC, USA
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