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Cao Z, Min X, Xie X, Huang M, Liu Y, Sun W, Xu G, He M, He K, Li Y, Yuan J. RIPK1 activation in Mecp2-deficient microglia promotes inflammation and glutamate release in RTT. Proc Natl Acad Sci U S A 2024; 121:e2320383121. [PMID: 38289948 PMCID: PMC10861890 DOI: 10.1073/pnas.2320383121] [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: 11/20/2023] [Accepted: 12/27/2023] [Indexed: 02/01/2024] Open
Abstract
Rett syndrome (RTT) is a devastating neurodevelopmental disorder primarily caused by mutations in the methyl-CpG binding protein 2 (Mecp2) gene. Here, we found that inhibition of Receptor-Interacting Serine/Threonine-Protein Kinase 1 (RIPK1) kinase ameliorated progression of motor dysfunction after onset and prolonged the survival of Mecp2-null mice. Microglia were activated early in myeloid Mecp2-deficient mice, which was inhibited upon inactivation of RIPK1 kinase. RIPK1 inhibition in Mecp2-deficient microglia reduced oxidative stress, cytokines production and induction of SLC7A11, SLC38A1, and GLS, which mediate the release of glutamate. Mecp2-deficient microglia release high levels of glutamate to impair glutamate-mediated excitatory neurotransmission and promote increased levels of GluA1 and GluA2/3 proteins in vivo, which was reduced upon RIPK1 inhibition. Thus, activation of RIPK1 kinase in Mecp2-deficient microglia may be involved both in the onset and progression of RTT.
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Affiliation(s)
- Ze Cao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- Shanghai Key Laboratory of Aging Studies, Shanghai201210, China
| | - Xia Min
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Xingxing Xie
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Maoqing Huang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Yingying Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Weimin Sun
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- Shanghai Key Laboratory of Aging Studies, Shanghai201210, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Guifang Xu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
| | - Miao He
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai200032, China
| | - Kaiwen He
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Ying Li
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- Shanghai Key Laboratory of Aging Studies, Shanghai201210, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Junying Yuan
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai201203, China
- Shanghai Key Laboratory of Aging Studies, Shanghai201210, China
- University of Chinese Academy of Sciences, Beijing100049, China
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Moore JR, Nemera MT, D’Souza RD, Hamagami N, Clemens AW, Beard DC, Urman A, Mendoza VR, Gabel HW. Non-CG DNA methylation and MeCP2 stabilize repeated tuning of long genes that distinguish closely related neuron types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.577861. [PMID: 38352532 PMCID: PMC10862856 DOI: 10.1101/2024.01.30.577861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
The extraordinary diversity of neuron types in the mammalian brain is delineated at the highest resolution by subtle gene expression differences that may require specialized molecular mechanisms to be maintained. Neurons uniquely express the longest genes in the genome and utilize neuron-enriched non-CG DNA methylation (mCA) together with the Rett syndrome protein, MeCP2, to control gene expression, but the function of these unique gene structures and machinery in regulating finely resolved neuron type-specific gene programs has not been explored. Here, we employ epigenomic and spatial transcriptomic analyses to discover a major role for mCA and MeCP2 in maintaining neuron type-specific gene programs at the finest scale of cellular resolution. We uncover differential susceptibility to MeCP2 loss in neuronal populations depending on global mCA levels and dissect methylation patterns and intragenic enhancer repression that drive overlapping and distinct gene regulation between neuron types. Strikingly, we show that mCA and MeCP2 regulate genes that are repeatedly tuned to differentiate neuron types at the highest cellular resolution, including spatially resolved, vision-dependent gene programs in the visual cortex. These repeatedly tuned genes display genomic characteristics, including long length, numerous intragenic enhancers, and enrichment for mCA, that predispose them to regulation by MeCP2. Thus, long gene regulation by the MeCP2 pathway maintains differential gene expression between closely-related neurons to facilitate the exceptional cellular diversity in the complex mammalian brain.
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Affiliation(s)
- J. Russell Moore
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Mati T. Nemera
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Rinaldo D. D’Souza
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Nicole Hamagami
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Adam W. Clemens
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Diana C. Beard
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Alaina Urman
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Victoria Rodriguez Mendoza
- Opportunities in Genomic Research Program, McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Harrison W. Gabel
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
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Zhang Q, Liu X, Gong L, He M. Combinatorial genetic strategies for dissecting cell lineages, cell types, and gene function in the mouse brain. Dev Growth Differ 2023; 65:546-553. [PMID: 37963088 DOI: 10.1111/dgd.12902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/26/2023] [Accepted: 11/06/2023] [Indexed: 11/16/2023]
Abstract
Research in neuroscience has greatly benefited from the development of genetic approaches that enable lineage tracing, cell type targeting, and conditional gene regulation. Recent advances in combinatorial strategies, which integrate multiple cellular features, have significantly enhanced the spatiotemporal precision and flexibility of these manipulations. In this minireview, we introduce the concept and design of these strategies and provide a few examples of their application in genetic fate mapping, cell type targeting, and reversible conditional gene regulation. These advancements have facilitated in-depth investigation into the developmental principles underlying the assembly of brain circuits, granting experimental access to highly specific cell lineages and subtypes, as well as offering valuable new tools for modeling and studying neurological diseases. Additionally, we discuss future directions aimed at expanding and improving the existing genetic toolkit for a better understanding of the development, structure, and function of healthy and diseased brains.
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Affiliation(s)
- Qi Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xue Liu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ling Gong
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Miao He
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
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Emerging strategies for the genetic dissection of gene functions, cell types, and neural circuits in the mammalian brain. Mol Psychiatry 2022; 27:422-435. [PMID: 34561609 DOI: 10.1038/s41380-021-01292-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 08/17/2021] [Accepted: 09/08/2021] [Indexed: 02/08/2023]
Abstract
The mammalian brain is composed of a large number of highly diverse cell types with different molecular, anatomical, and functional features. Distinct cellular identities are generated during development under the regulation of intricate genetic programs and manifested through unique combinations of gene expression. Recent advancements in our understanding of the molecular and cellular mechanisms underlying the assembly, function, and pathology of the brain circuitry depend on the invention and application of genetic strategies that engage intrinsic gene regulatory mechanisms. Here we review the strategies for gene regulation on DNA, RNA, and protein levels and their applications in cell type targeting and neural circuit dissection. We highlight newly emerged strategies and emphasize the importance of combinatorial approaches. We also discuss the potential caveats and pitfalls in current methods and suggest future prospects to improve their comprehensiveness and versatility.
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