1
|
Bear R, Sloan SA, Caspary T. Primary cilia shape postnatal astrocyte development through Sonic Hedgehog signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.17.618851. [PMID: 39464094 PMCID: PMC11507945 DOI: 10.1101/2024.10.17.618851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/29/2024]
Abstract
Primary cilia function as specialized signaling centers that regulate many cellular processes including neuron and glia development. Astrocytes possess cilia, but the function of cilia in astrocyte development remains largely unexplored. Critically, dysfunction of either astrocytes or cilia contributes to molecular changes observed in neurodevelopmental disorders. Here, we show that a sub-population of developing astrocytes in the prefrontal cortex are ciliated. This population corresponds to proliferating astrocytes and largely expresses the ciliary protein ARL13B. Genetic ablation of astrocyte cilia in vivo at two distinct stages of astrocyte development results in changes to Sonic Hedgehog (Shh) transcriptional targets. We show that Shh activity is decreased in immature and mature astrocytes upon loss of cilia. Furthermore, loss of cilia in immature astrocytes results in decreased astrocyte proliferation and loss of cilia in mature astrocytes causes enlarged astrocyte morphology. Together, these results indicate that astrocytes require cilia for Shh signaling throughout development and uncover functions for astrocyte cilia in regulating astrocyte proliferation and maturation. This expands our fundamental knowledge of astrocyte development and cilia function to advance our understanding of neurodevelopmental disorders.
Collapse
|
2
|
Brase L, Yu Y, McDade E, Harari O, Benitez BA. Comparative gene regulatory networks modulating APOE expression in microglia and astrocytes. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.19.24306098. [PMID: 38699303 PMCID: PMC11065001 DOI: 10.1101/2024.04.19.24306098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Background Single-cell technologies have unveiled various transcriptional states in different brain cell types. Transcription factors (TFs) regulate the expression of related gene sets, thereby controlling these diverse expression states. Apolipoprotein E (APOE), a pivotal risk-modifying gene in Alzheimer's disease (AD), is expressed in specific glial transcriptional states associated with AD. However, it is still unknown whether the upstream regulatory programs that modulate its expression are shared across brain cell types or specific to microglia and astrocytes. Methods We used pySCENIC to construct state-specific gene regulatory networks (GRNs) for resting and activated cell states within microglia and astrocytes based on single-nucleus RNA sequencing data from AD patients' cortices from the Knight ADRC-DIAN cohort. We then identified replicating TF using data from the ROSMAP cohort. We identified sets of genes co-regulated with APOE by clustering the GRN target genes and identifying genes differentially expressed after the virtual knockout of TFs regulating APOE. We performed enrichment analyses on these gene sets and evaluated their overlap with genes found in AD GWAS loci. Results We identified an average of 96 replicating regulators for each microglial and astrocyte cell state. Our analysis identified the CEBP, JUN, FOS, and FOXO TF families as key regulators of microglial APOE expression. The steroid/thyroid hormone receptor families, including the THR TF family, consistently regulated APOE across astrocyte states, while CEBP and JUN TF families were also involved in resting astrocytes. AD GWAS-associated genes (PGRN, FCGR3A, CTSH, ABCA1, MARCKS, CTSB, SQSTM1, TSC22D4, FCER1G, and HLA genes) are co-regulated with APOE. We also uncovered that APOE-regulating TFs were linked to circadian rhythm (BHLHE40, DBP, XBP1, CREM, SREBF1, FOXO3, and NR2F1). Conclusions Our findings reveal a novel perspective on the transcriptional regulation of APOE in the human brain. We found a comprehensive and cell-type-specific regulatory landscape for APOE, revealing distinct and shared regulatory mechanisms across microglia and astrocytes, underscoring the complexity of APOE regulation. APOE-co-regulated genes might also affect AD risk. Furthermore, our study uncovers a potential link between circadian rhythm disruption and APOE regulation, shedding new light on the pathogenesis of AD.
Collapse
Affiliation(s)
- Logan Brase
- Department of Psychiatry, Washington University, Saint Louis, St. Louis, Missouri, United States of America
- The Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University, St. Louis, Missouri, United States of America
| | - Yanbo Yu
- Department of Psychiatry, Washington University, Saint Louis, St. Louis, Missouri, United States of America
- The Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University, St. Louis, Missouri, United States of America
| | - Eric McDade
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | | | - Oscar Harari
- Department of Psychiatry, Washington University, Saint Louis, St. Louis, Missouri, United States of America
- The Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University, St. Louis, Missouri, United States of America
- Department of Neurology, Division of Neurogenetics, The Ohio State University, Columbus, OH, United States of America
| | - Bruno A. Benitez
- Department of Neurology and Neuroscience, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| |
Collapse
|
3
|
Faust TE, Lee YH, O’Connor CD, Boyle MA, Gunner G, Badimon A, Ayata P, Schaefer A, Schafer DP. Microglia-astrocyte crosstalk regulates synapse remodeling via Wnt signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.08.579178. [PMID: 38370645 PMCID: PMC10871360 DOI: 10.1101/2024.02.08.579178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Astrocytes and microglia are emerging key regulators of activity-dependent synapse remodeling that engulf and remove synapses in response to changes in neural activity. Yet, the degree to which these cells communicate to coordinate this process remains an open question. Here, we use whisker removal in postnatal mice to induce activity-dependent synapse removal in the barrel cortex. We show that astrocytes do not engulf synapses in this paradigm. Instead, astrocytes reduce their contact with synapses prior to microglia-mediated synapse engulfment. We further show that reduced astrocyte-contact with synapses is dependent on microglial CX3CL1-CX3CR1 signaling and release of Wnts from microglia following whisker removal. These results demonstrate an activity-dependent mechanism by which microglia instruct astrocyte-synapse interactions, which then provides a permissive environment for microglia to remove synapses. We further show that this mechanism is critical to remodel synapses in a changing sensory environment and this signaling is upregulated in several disease contexts.
Collapse
Affiliation(s)
- Travis E. Faust
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Yi-Han Lee
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- These authors contributed equally
| | - Ciara D. O’Connor
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada K7L 3N6
- These authors contributed equally
| | - Margaret A. Boyle
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- These authors contributed equally
| | - Georgia Gunner
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Ana Badimon
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Patricia and John Rosenwald Laboratory of Neurobiology and Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Pinar Ayata
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York Graduate Center, New York, NY 10031, USA
| | - Anne Schaefer
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Dorothy P. Schafer
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Lead contact
| |
Collapse
|
4
|
Holt LM, Gyles TM, Parise EM, Minier-Toribio A, Markovic T, Rivera M, Yeh SY, Nestler EJ. Astrocytic CREB in nucleus accumbens promotes susceptibility to chronic stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575728. [PMID: 38293227 PMCID: PMC10827054 DOI: 10.1101/2024.01.15.575728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Background Increasing evidence implicates astrocytes in stress and depression in both rodent models and human Major Depressive Disorder (MDD). Despite this, little is known about the transcriptional responses to stress of astrocytes within the nucleus accumbens (NAc), a key brain reward region, and their influence on behavioral outcomes. Methods We used whole cell sorting, RNA-sequencing, and bioinformatic analyses to investigate the NAc astrocyte transcriptome in male mice in response to chronic social defeat stress (CSDS). Immunohistochemistry was used to determine stress-induced changes in astrocytic CREB within the NAc. Finally, astrocytic regulation of depression-like behavior was investigated using viral-mediated manipulation of CREB in combination with CSDS. Results We found a robust transcriptional response in NAc astrocytes to CSDS in stressed mice, with changes seen in both stress-susceptible and stress-resilient animals. Bioinformatic analysis revealed CREB, a transcription factor widely studied in neurons, as one of the top-predicted upstream regulators of the NAc astrocyte transcriptome, with opposite activation states seen in resilient versus susceptible mice. This bioinformatic result was confirmed at the protein level with immunohistochemistry. Viral overexpression of CREB selectively in NAc astrocytes promoted susceptibility to chronic stress. Conclusions Together, our data demonstrate that the astrocyte transcriptome responds robustly to CSDS and, for the first time, that transcriptional regulation in astrocytes contributes to depressive-like behaviors. A better understanding of transcriptional regulation in astrocytes may reveal unknown molecular mechanisms underlying neuropsychiatric disorders.
Collapse
Affiliation(s)
- Leanne M. Holt
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Trevonn M Gyles
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Eric M. Parise
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Angelica Minier-Toribio
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Tamara Markovic
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Matthew Rivera
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Szu-Ying Yeh
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Eric J. Nestler
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| |
Collapse
|
5
|
Imrie G, Gray MB, Raghuraman V, Farhy-Tselnicker I. Gene Expression at the Tripartite Synapse: Bridging the Gap Between Neurons and Astrocytes. ADVANCES IN NEUROBIOLOGY 2024; 39:95-136. [PMID: 39190073 DOI: 10.1007/978-3-031-64839-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Astrocytes, a major class of glial cells, are an important element at the synapse where they engage in bidirectional crosstalk with neurons to regulate numerous aspects of neurotransmission, circuit function, and behavior. Mutations in synapse-related genes expressed in both neurons and astrocytes are central factors in a vast number of neurological disorders, making the proteins that they encode prominent targets for therapeutic intervention. Yet, while the roles of many of these synaptic proteins in neurons are well established, the functions of the same proteins in astrocytes are largely unknown. This gap in knowledge must be addressed to refine therapeutic approaches. In this chapter, we integrate multiomic meta-analysis and a comprehensive overview of current literature to show that astrocytes express an astounding number of genes that overlap with the neuronal and synaptic transcriptomes. Further, we highlight recent reports that characterize the expression patterns and potential novel roles of these genes in astrocytes in both physiological and pathological conditions, underscoring the importance of considering both cell types when investigating the function and regulation of synaptic proteins.
Collapse
Affiliation(s)
- Gillian Imrie
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Madison B Gray
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Vishnuvasan Raghuraman
- Department of Biology, Texas A&M University, College Station, TX, USA
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Isabella Farhy-Tselnicker
- Department of Biology, Texas A&M University, College Station, TX, USA.
- Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX, USA.
- Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA.
| |
Collapse
|