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Wang L, Zheng J, Zhao S, Wan Y, Wang M, Bosco DB, Kuan CY, Richardson JR, Wu LJ. CCR2 + monocytes replenish border-associated macrophages in the diseased mouse brain. Cell Rep 2024; 43:114120. [PMID: 38625796 PMCID: PMC11105166 DOI: 10.1016/j.celrep.2024.114120] [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: 08/05/2023] [Revised: 02/06/2024] [Accepted: 03/30/2024] [Indexed: 04/18/2024] Open
Abstract
Border-associated macrophages (BAMs) are tissue-resident macrophages that reside at the border of the central nervous system (CNS). Since BAMs originate from yolk sac progenitors that do not persist after birth, the means by which this population of cells is maintained is not well understood. Using two-photon microscopy and multiple lineage-tracing strategies, we determine that CCR2+ monocytes are significant contributors to BAM populations following disruptions of CNS homeostasis in adult mice. After BAM depletion, while the residual BAMs possess partial self-repopulation capability, the CCR2+ monocytes are a critical source of the repopulated BAMs. In addition, we demonstrate the existence of CCR2+ monocyte-derived long-lived BAMs in a brain compression model and in a sepsis model after the initial disruption of homeostasis. Our study reveals that the short-lived CCR2+ monocytes transform into long-lived BAM-like cells at the CNS border and subsequently contribute to BAM populations.
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Affiliation(s)
- Lingxiao Wang
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Yushan Wan
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Meijie Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Dale B Bosco
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Chia-Yi Kuan
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jason R Richardson
- Department of Environmental Health Science, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Center for Neuroimmunology and Glial Biology, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Zhao S, Umpierre AD, Wu LJ. Tuning neural circuits and behaviors by microglia in the adult brain. Trends Neurosci 2024; 47:181-194. [PMID: 38245380 PMCID: PMC10939815 DOI: 10.1016/j.tins.2023.12.003] [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: 07/07/2023] [Revised: 11/04/2023] [Accepted: 12/21/2023] [Indexed: 01/22/2024]
Abstract
Microglia are the primary immune cells of the CNS, contributing to both inflammatory damage and tissue repair in neurological disorder. In addition, emerging evidence highlights the role of homeostatic microglia in regulating neuronal activity, interacting with synapses, tuning neural circuits, and modulating behaviors. Herein, we review how microglia sense and regulate neuronal activity through synaptic interactions, thereby directly engaging with neural networks and behaviors. We discuss current studies utilizing microglial optogenetic and chemogenetic approaches to modulate adult neural circuits. These manipulations of microglia across different CNS regions lead to diverse behavioral consequences. We propose that spatial heterogeneity of microglia-neuron interaction lays the groundwork for understanding diverse functions of microglia in neural circuits and behaviors.
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Affiliation(s)
- Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | | | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Department of Immunology, Mayo Clinic, Rochester, MN, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
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Zhao S, Wang L, Liang Y, Zheng J, Umpierre AD, Wu LJ. Chemogenetic activation of microglial Gi signaling decreases microglial surveillance and impairs neuronal synchronization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.12.579861. [PMID: 38405754 PMCID: PMC10888941 DOI: 10.1101/2024.02.12.579861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Microglia actively survey the brain and dynamically interact with neurons to maintain brain homeostasis. Microglial Gi-protein coupled receptors (Gi-GPCRs) play a critical role in microglia-neuron communications. However, the impact of temporally activating microglial Gi signaling on microglial dynamics and neuronal activity in the homeostatic brain remains largely unknown. In this study, we employed Gi-based Designer Receptors Exclusively Activated by Designer Drugs (Gi-DREADD) to selectively and temporally modulate microglial Gi signaling pathway. By integrating this chemogenetic approach with in vivo two-photon imaging, we observed that exogenous activation of microglial Gi signaling transiently inhibited microglial process dynamics, reduced neuronal activity, and impaired neuronal synchronization. These altered neuronal functions were associated with a decrease in interactions between microglia and neuron somata. Altogether, this study demonstrates that acute, exogenous activation of microglial Gi signaling can regulate neuronal circuit function, offering a potential pharmacological target for neuromodulation through microglia.
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