1
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Whitsitt Q, Saxena A, Patel B, Evans BM, Hunt B, Purcell EK. Spatial transcriptomics at the brain-electrode interface in rat motor cortex and the relationship to recording quality. J Neural Eng 2024; 21:046033. [PMID: 38885679 PMCID: PMC11289622 DOI: 10.1088/1741-2552/ad5936] [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: 11/17/2023] [Revised: 04/15/2024] [Accepted: 06/17/2024] [Indexed: 06/20/2024]
Abstract
Study of the foreign body reaction to implanted electrodes in the brain is an important area of research for the future development of neuroprostheses and experimental electrophysiology. After electrode implantation in the brain, microglial activation, reactive astrogliosis, and neuronal cell death create an environment immediately surrounding the electrode that is significantly altered from its homeostatic state.Objective.To uncover physiological changes potentially affecting device function and longevity, spatial transcriptomics (ST) was implemented to identify changes in gene expression driven by electrode implantation and compare this differential gene expression to traditional metrics of glial reactivity, neuronal loss, and electrophysiological recording quality.Approach.For these experiments, rats were chronically implanted with functional Michigan-style microelectrode arrays, from which electrophysiological recordings (multi-unit activity, local field potential) were taken over a six-week time course. Brain tissue cryosections surrounding each electrode were then mounted for ST processing. The tissue was immunolabeled for neurons and astrocytes, which provided both a spatial reference for ST and a quantitative measure of glial fibrillary acidic protein and neuronal nuclei immunolabeling surrounding each implant.Main results. Results from rat motor cortex within 300µm of the implanted electrodes at 24 h, 1 week, and 6 weeks post-implantation showed up to 553 significantly differentially expressed (DE) genes between implanted and non-implanted tissue sections. Regression on the significant DE genes identified the 6-7 genes that had the strongest relationship to histological and electrophysiological metrics, revealing potential candidate biomarkers of recording quality and the tissue response to implanted electrodes.Significance. Our analysis has shed new light onto the potential mechanisms involved in the tissue response to implanted electrodes while generating hypotheses regarding potential biomarkers related to recorded signal quality. A new approach has been developed to understand the tissue response to electrodes implanted in the brain using genes identified through transcriptomics, and to screen those results for potential relationships with functional outcomes.
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Affiliation(s)
- Quentin Whitsitt
- Department of Biomedical Engineering and Institute of Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Akash Saxena
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Bella Patel
- Department of Biomedical Engineering and Institute of Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Blake M Evans
- Department of Biomedical Engineering and Institute of Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Bradley Hunt
- Department of Biomedical Engineering and Institute of Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Erin K Purcell
- Department of Biomedical Engineering and Institute of Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, United States of America
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2
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Wahbeh MH, Boyd RJ, Yovo C, Rike B, McCallion AS, Avramopoulos D. A functional schizophrenia-associated genetic variant near the TSNARE1 and ADGRB1 genes. HGG ADVANCES 2024; 5:100303. [PMID: 38702885 PMCID: PMC11130735 DOI: 10.1016/j.xhgg.2024.100303] [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: 12/22/2023] [Revised: 05/01/2024] [Accepted: 04/23/2024] [Indexed: 05/06/2024] Open
Abstract
Recent collaborative genome-wide association studies (GWAS) have identified >200 independent loci contributing to risk for schizophrenia (SCZ). The genes closest to these loci have diverse functions, supporting the potential involvement of multiple relevant biological processes, yet there is no direct evidence that individual variants are functional or directly linked to specific genes. Nevertheless, overlap with certain epigenetic marks suggest that most GWAS-implicated variants are regulatory. Based on the strength of association with SCZ and the presence of regulatory epigenetic marks, we chose one such variant near TSNARE1 and ADGRB1, rs4129585, to test for functional potential and assay differences that may drive the pathogenicity of the risk allele. We observed that the variant-containing sequence drives reporter expression in relevant neuronal populations in zebrafish. Next, we introduced each allele into human induced pluripotent cells and differentiated four isogenic clones homozygous for the risk allele and five clones homozygous for the non-risk allele into neural progenitor cells. Employing RNA sequencing, we found that the two alleles yield significant transcriptional differences in the expression of 109 genes at a false discovery rate (FDR) of <0.05 and 259 genes at a FDR of <0.1. We demonstrate that these genes are highly interconnected in pathways enriched for synaptic proteins, axon guidance, and regulation of synapse assembly. Exploration of genes near rs4129585 suggests that this variant does not regulate TSNARE1 transcripts, as previously thought, but may regulate the neighboring ADGRB1, a regulator of synaptogenesis. Our results suggest that rs4129585 is a functional common variant that functions in specific pathways likely involved in SCZ risk.
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Affiliation(s)
- Marah H Wahbeh
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rachel J Boyd
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christian Yovo
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bailey Rike
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrew S McCallion
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dimitrios Avramopoulos
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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3
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Parag RR, Yamamoto T, Saito K, Zhu D, Yang L, Van Meir EG. Novel Isoforms of Adhesion G Protein-Coupled Receptor B1 (ADGRB1/BAI1) Generated from an Alternative Promoter in Intron 17. Mol Neurobiol 2024:10.1007/s12035-024-04293-3. [PMID: 38941066 DOI: 10.1007/s12035-024-04293-3] [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: 02/24/2024] [Accepted: 06/06/2024] [Indexed: 06/29/2024]
Abstract
Brain-specific angiogenesis inhibitor 1 (BAI1) belongs to the adhesion G-protein-coupled receptors, which exhibit large multi-domain extracellular N termini that mediate cell-cell and cell-matrix interactions. To explore the existence of BAI1 isoforms, we queried genomic datasets for markers of active chromatin and new transcript variants in the ADGRB1 (adhesion G-protein-coupled receptor B1) gene. Two major types of mRNAs were identified in human/mouse brain, those with a start codon in exon 2 encoding a full-length protein of a predicted size of 173.5/173.3 kDa and shorter transcripts starting from alternative exons at the intron 17/exon 18 boundary with new or exon 19 start codons, predicting two shorter isoforms of 76.9/76.4 and 70.8/70.5 kDa, respectively. Immunoblots on wild-type and Adgrb1 exon 2-deleted mice, reverse transcription PCR, and promoter-luciferase reporter assay confirmed that the shorter isoforms originate from an alternative promoter in intron 17. The shorter BAI1 isoforms lack most of the N terminus and are very close in structure to the truncated BAI1 isoform generated through GPS processing from the full-length receptor. The cleaved BAI1 isoform has a 19 amino acid extracellular stalk that may serve as a receptor agonist, while the alternative transcripts generate BAI1 isoforms with extracellular N termini of 5 or 60 amino acids. Further studies are warranted to compare the functions of these isoforms and examine the distinct roles they play in different tissues and cell types.
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Affiliation(s)
- Rashed Rezwan Parag
- Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery, Heersink School of Medicine, University of Alabama at Birmingham (UAB), WTI 520E, 1824 6th Avenue South, Birmingham, AL, 35233, USA
- Graduate Biomedical Sciences, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Takahiro Yamamoto
- Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery, Heersink School of Medicine, University of Alabama at Birmingham (UAB), WTI 520E, 1824 6th Avenue South, Birmingham, AL, 35233, USA
- Department of Neurosurgery, Kumamoto University, Kumamoto, Japan
| | - Kiyotaka Saito
- Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery, Heersink School of Medicine, University of Alabama at Birmingham (UAB), WTI 520E, 1824 6th Avenue South, Birmingham, AL, 35233, USA
| | - Dan Zhu
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Liquan Yang
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Erwin G Van Meir
- Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery, Heersink School of Medicine, University of Alabama at Birmingham (UAB), WTI 520E, 1824 6th Avenue South, Birmingham, AL, 35233, USA.
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA.
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.
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4
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Carlton AJ, Jeng JY, Grandi FC, De Faveri F, Amariutei AE, De Tomasi L, O'Connor A, Johnson SL, Furness DN, Brown SDM, Ceriani F, Bowl MR, Mustapha M, Marcotti W. BAI1 localizes AMPA receptors at the cochlear afferent post-synaptic density and is essential for hearing. Cell Rep 2024; 43:114025. [PMID: 38564333 DOI: 10.1016/j.celrep.2024.114025] [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: 09/14/2023] [Revised: 01/25/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
Type I spiral ganglion neurons (SGNs) convey sound information to the central auditory pathway by forming synapses with inner hair cells (IHCs) in the mammalian cochlea. The molecular mechanisms regulating the formation of the post-synaptic density (PSD) in the SGN afferent terminals are still unclear. Here, we demonstrate that brain-specific angiogenesis inhibitor 1 (BAI1) is required for the clustering of AMPA receptors GluR2-4 (glutamate receptors 2-4) at the PSD. Adult Bai1-deficient mice have functional IHCs but fail to transmit information to the SGNs, leading to highly raised hearing thresholds. Despite the almost complete absence of AMPA receptor subunits, the SGN fibers innervating the IHCs do not degenerate. Furthermore, we show that AMPA receptors are still expressed in the cochlea of Bai1-deficient mice, highlighting a role for BAI1 in trafficking or anchoring GluR2-4 to the PSDs. These findings identify molecular and functional mechanisms required for sound encoding at cochlear ribbon synapses.
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Affiliation(s)
- Adam J Carlton
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Jing-Yi Jeng
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Fiorella C Grandi
- Sorbonne Université, INSERM, Institute de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | | | - Ana E Amariutei
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Lara De Tomasi
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew O'Connor
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Stuart L Johnson
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK; Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - David N Furness
- School of Life Sciences, Keele University, Keele ST5 5BG, UK
| | - Steve D M Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Federico Ceriani
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Michael R Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Mirna Mustapha
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK; Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK; Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK.
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5
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Wahbeh MH, Boyd RJ, Yovo C, Rike B, McCallion AS, Avramopoulos D. A Functional Schizophrenia-associated genetic variant near the TSNARE1 and ADGRB1 genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.570831. [PMID: 38187620 PMCID: PMC10769312 DOI: 10.1101/2023.12.18.570831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Recent collaborative genome wide association studies (GWAS) have identified >200 independent loci contributing to risk for schizophrenia (SCZ). The genes closest to these loci have diverse functions, supporting the potential involvement of multiple relevant biological processes; yet there is no direct evidence that individual variants are functional or directly linked to specific genes. Nevertheless, overlap with certain epigenetic marks suggest that most GWAS-implicated variants are regulatory. Based on the strength of association with SCZ and the presence of regulatory epigenetic marks, we chose one such variant near TSNARE1 and ADGRB1, rs4129585, to test for functional potential and assay differences that may drive the pathogenicity of the risk allele. We observed that the variant-containing sequence drives reporter expression in relevant neuronal populations in zebrafish. Next, we introduced each allele into human induced pluripotent cells and differentiated 4 isogenic clones homozygous for the risk allele and 5 clones homozygous for the non-risk allele into neural precursor cells. Employing RNA-seq, we found that the two alleles yield significant transcriptional differences in the expression of 109 genes at FDR <0.05 and 259 genes at FDR <0.1. We demonstrate that these genes are highly interconnected in pathways enriched for synaptic proteins, axon guidance, and regulation of synapse assembly. Exploration of genes near rs4129585 suggests that this variant does not regulate TSNARE1 transcripts, as previously thought, but may regulate the neighboring ADGRB1, a regulator of synaptogenesis. Our results suggest that rs4129585 is a functional common variant that functions in specific pathways likely involved in SCZ risk.
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Affiliation(s)
- Marah H Wahbeh
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rachel J Boyd
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christian Yovo
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bailey Rike
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrew S McCallion
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dimitrios Avramopoulos
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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6
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Aimi T, Matsuda K, Yuzaki M. C1ql1-Bai3 signaling is necessary for climbing fiber synapse formation in mature Purkinje cells in coordination with neuronal activity. Mol Brain 2023; 16:61. [PMID: 37488606 PMCID: PMC10367388 DOI: 10.1186/s13041-023-01048-4] [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: 02/27/2023] [Accepted: 07/05/2023] [Indexed: 07/26/2023] Open
Abstract
Changes in neural activity induced by learning and novel environments have been reported to lead to the formation of new synapses in the adult brain. However, the underlying molecular mechanism is not well understood. Here, we show that Purkinje cells (PCs), which have established adult-type monosynaptic innervation by climbing fibers (CFs) after elimination of weak CFs during development, can be reinnervated by multiple CFs by increased expression of the synaptic organizer C1ql1 in CFs or Bai3, a receptor for C1ql1, in PCs. In the adult cerebellum, CFs are known to have transverse branches that run in a mediolateral direction without forming synapses with PCs. Electrophysiological, Ca2+-imaging and immunohistochemical studies showed that overexpression of C1ql1 or Bai3 caused these CF transverse branches to elongate and synapse on the distal dendrites of mature PCs. Mature PCs were also reinnervated by multiple CFs when the glutamate receptor GluD2, which is essential for the maintenance of synapses between granule cells and PCs, was deleted. Interestingly, the effect of GluD2 knockout was not observed in Bai3 knockout PCs. In addition, C1ql1 levels were significantly upregulated in CFs of GluD2 knockout mice, suggesting that endogenous, not overexpressed, C1ql1-Bai3 signaling could regulate the reinnervation of mature PCs by CFs. Furthermore, the effects of C1ql1 and Bai3 overexpression required neuronal activity in the PC and CF, respectively. C1ql1 immunoreactivity at CF-PC synapses was reduced when the neuronal activity of CFs was suppressed. These results suggest that C1ql1-Bai3 signaling may mediate CF synaptogenesis in mature PCs, potentially in concert with neuronal activity.
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Affiliation(s)
- Takahiro Aimi
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Keiko Matsuda
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan.
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7
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Lala T, Doan JK, Takatsu H, Hartzell HC, Shin HW, Hall RA. Phosphatidylserine exposure modulates adhesion GPCR BAI1 (ADGRB1) signaling activity. J Biol Chem 2022; 298:102685. [PMID: 36370845 PMCID: PMC9723945 DOI: 10.1016/j.jbc.2022.102685] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/10/2022] Open
Abstract
Brain-specific angiogenesis inhibitor 1 (BAI1; also called ADGRB1 or B1) is an adhesion G protein-coupled receptor known from studies on macrophages to bind to phosphatidylserine (PS) on apoptotic cells via its N-terminal thrombospondin repeats. A separate body of work has shown that B1 regulates postsynaptic function and dendritic spine morphology via signaling pathways involving Rac and Rho. However, it is unknown if PS binding by B1 has any effect on the receptor's signaling activity. To shed light on this subject, we studied G protein-dependent signaling by B1 in the absence and presence of coexpression with the PS flippase ATP11A in human embryonic kidney 293T cells. ATP11A expression reduced the amount of PS exposed extracellularly and also strikingly reduced the signaling activity of coexpressed full-length B1 but not a truncated version of the receptor lacking the thrombospondin repeats. Further experiments with an inactive mutant of ATP11A showed that the PS flippase function of ATP11A was required for modulation of B1 signaling. In coimmunoprecipitation experiments, we made the surprising finding that ATP11A not only modulates B1 signaling but also forms complexes with B1. Parallel studies in which PS in the outer leaflet was reduced by an independent method, deletion of the gene encoding the endogenous lipid scramblase anoctamin 6 (ANO6), revealed that this manipulation also markedly reduced B1 signaling. These findings demonstrate that B1 signaling is modulated by PS exposure and suggest a model in which B1 serves as a PS sensor at synapses and in other cellular contexts.
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Affiliation(s)
- Trisha Lala
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Juleva K Doan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hiroyuki Takatsu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hye-Won Shin
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Randy A Hall
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.
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8
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Lala T, Hall RA. Adhesion G protein-coupled receptors: structure, signaling, physiology, and pathophysiology. Physiol Rev 2022; 102:1587-1624. [PMID: 35468004 PMCID: PMC9255715 DOI: 10.1152/physrev.00027.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 03/11/2022] [Accepted: 04/16/2022] [Indexed: 01/17/2023] Open
Abstract
Adhesion G protein-coupled receptors (AGPCRs) are a family of 33 receptors in humans exhibiting a conserved general structure but diverse expression patterns and physiological functions. The large NH2 termini characteristic of AGPCRs confer unique properties to each receptor and possess a variety of distinct domains that can bind to a diverse array of extracellular proteins and components of the extracellular matrix. The traditional view of AGPCRs, as implied by their name, is that their core function is the mediation of adhesion. In recent years, though, many surprising advances have been made regarding AGPCR signaling mechanisms, activation by mechanosensory forces, and stimulation by small-molecule ligands such as steroid hormones and bioactive lipids. Thus, a new view of AGPCRs has begun to emerge in which these receptors are seen as massive signaling platforms that are crucial for the integration of adhesive, mechanosensory, and chemical stimuli. This review article describes the recent advances that have led to this new understanding of AGPCR function and also discusses new insights into the physiological actions of these receptors as well as their roles in human disease.
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Affiliation(s)
- Trisha Lala
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia
| | - Randy A Hall
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia
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9
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Shiu FH, Wong JC, Yamamoto T, Lala T, Purcell RH, Owino S, Zhu D, Van Meir EG, Hall RA, Escayg A. Mice lacking full length Adgrb1 (Bai1) exhibit social deficits, increased seizure susceptibility, and altered brain development. Exp Neurol 2022; 351:113994. [PMID: 35114205 PMCID: PMC9817291 DOI: 10.1016/j.expneurol.2022.113994] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 12/20/2021] [Accepted: 01/24/2022] [Indexed: 01/11/2023]
Abstract
The adhesion G protein-coupled receptor BAI1/ADGRB1 plays an important role in suppressing angiogenesis, mediating phagocytosis, and acting as a brain tumor suppressor. BAI1 is also a critical regulator of dendritic spine and excitatory synapse development and interacts with several autism-relevant proteins. However, little is known about the relationship between altered BAI1 function and clinically relevant phenotypes. Therefore, we studied the effect of reduced expression of full length Bai1 on behavior, seizure susceptibility, and brain morphology in Adgrb1 mutant mice. We compared homozygous (Adgrb1-/-), heterozygous (Adgrb1+/-), and wild-type (WT) littermates using a battery of tests to assess social behavior, anxiety, repetitive behavior, locomotor function, and seizure susceptibility. We found that Adgrb1-/- mice showed significant social behavior deficits and increased vulnerability to seizures. Adgrb1-/- mice also showed delayed growth and reduced brain weight. Furthermore, reduced neuron density and increased apoptosis during brain development were observed in the hippocampus of Adgrb1-/- mice, while levels of astrogliosis and microgliosis were comparable to WT littermates. These results show that reduced levels of full length Bai1 is associated with a broader range of clinically relevant phenotypes than previously reported.
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Affiliation(s)
- Fu Hung Shiu
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA; Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA
| | - Jennifer C Wong
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Takahiro Yamamoto
- Department of Neurosurgery, School of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Trisha Lala
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA; Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Ryan H Purcell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Sharon Owino
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Dan Zhu
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Erwin G Van Meir
- Department of Neurosurgery, School of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA; O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Randy A Hall
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.
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10
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Bajar BT, Guan X, Lam A, Lin MZ, Yasuda R, Laviv T, Chu J. FRET Imaging of Rho GTPase Activity with Red Fluorescent Protein-Based FRET Pairs. Methods Mol Biol 2022; 2438:31-43. [PMID: 35147933 PMCID: PMC9976416 DOI: 10.1007/978-1-0716-2035-9_2] [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] [Indexed: 10/19/2022]
Abstract
With the development of fluorescent proteins (FPs) and advanced optical microscopy techniques, Förster or fluorescence resonance energy transfer (FRET) has become a powerful tool for real-time noninvasive visualization of a variety of biological processes, including kinase activities, with high spatiotemporal resolution in living cells and organisms. FRET can be detected in appropriately configured microscopes as changes in fluorescence intensity, lifetime, and anisotropy. Here, we describe the preparation of samples expressing FP-based FRET sensors for RhoA kinase, intensity- and lifetime-based FRET imaging, and postimaging data analysis.
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Affiliation(s)
- Bryce T Bajar
- Department of Biological Chemistry, Medical Scientist Training Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Xinmeng Guan
- Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology & Center for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Amy Lam
- Departments of Neurobiology and Bioengineering, Stanford University, Stanford, CA, USA
| | - Michael Z Lin
- Departments of Neurobiology and Bioengineering, Stanford University, Stanford, CA, USA
| | - Ryohei Yasuda
- Neuronal Signal Transduction Group, Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Tal Laviv
- Neuronal Signal Transduction Group, Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA.
- Department of Physiology and Pharmacology, Sackler School of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
| | - Jun Chu
- Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology & Center for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
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11
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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12
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Wang J, Miao Y, Wicklein R, Sun Z, Wang J, Jude KM, Fernandes RA, Merrill SA, Wernig M, Garcia KC, Südhof TC. RTN4/NoGo-receptor binding to BAI adhesion-GPCRs regulates neuronal development. Cell 2021; 184:5869-5885.e25. [PMID: 34758294 PMCID: PMC8620742 DOI: 10.1016/j.cell.2021.10.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/01/2021] [Accepted: 10/13/2021] [Indexed: 10/19/2022]
Abstract
RTN4-binding proteins were widely studied as "NoGo" receptors, but their physiological interactors and roles remain elusive. Similarly, BAI adhesion-GPCRs were associated with numerous activities, but their ligands and functions remain unclear. Using unbiased approaches, we observed an unexpected convergence: RTN4 receptors are high-affinity ligands for BAI adhesion-GPCRs. A single thrombospondin type 1-repeat (TSR) domain of BAIs binds to the leucine-rich repeat domain of all three RTN4-receptor isoforms with nanomolar affinity. In the 1.65 Å crystal structure of the BAI1/RTN4-receptor complex, C-mannosylation of tryptophan and O-fucosylation of threonine in the BAI TSR-domains creates a RTN4-receptor/BAI interface shaped by unusual glycoconjugates that enables high-affinity interactions. In human neurons, RTN4 receptors regulate dendritic arborization, axonal elongation, and synapse formation by differential binding to glial versus neuronal BAIs, thereby controlling neural network activity. Thus, BAI binding to RTN4/NoGo receptors represents a receptor-ligand axis that, enabled by rare post-translational modifications, controls development of synaptic circuits.
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Affiliation(s)
- Jie Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yi Miao
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rebecca Wicklein
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zijun Sun
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinzhao Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ricardo A Fernandes
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sean A Merrill
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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13
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Islam MR, Valaris S, Young MF, Haley EB, Luo R, Bond SF, Mazuera S, Kitchen RR, Caldarone BJ, Bettio LEB, Christie BR, Schmider AB, Soberman RJ, Besnard A, Jedrychowski MP, Kim H, Tu H, Kim E, Choi SH, Tanzi RE, Spiegelman BM, Wrann CD. Exercise hormone irisin is a critical regulator of cognitive function. Nat Metab 2021; 3:1058-1070. [PMID: 34417591 DOI: 10.1038/s42255-021-00438-z] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 07/13/2021] [Indexed: 02/07/2023]
Abstract
Identifying secreted mediators that drive the cognitive benefits of exercise holds great promise for the treatment of cognitive decline in ageing or Alzheimer's disease (AD). Here, we show that irisin, the cleaved and circulating form of the exercise-induced membrane protein FNDC5, is sufficient to confer the benefits of exercise on cognitive function. Genetic deletion of Fndc5/irisin (global Fndc5 knock-out (KO) mice; F5KO) impairs cognitive function in exercise, ageing and AD. Diminished pattern separation in F5KO mice can be rescued by delivering irisin directly into the dentate gyrus, suggesting that irisin is the active moiety. In F5KO mice, adult-born neurons in the dentate gyrus are morphologically, transcriptionally and functionally abnormal. Importantly, elevation of circulating irisin levels by peripheral delivery of irisin via adeno-associated viral overexpression in the liver results in enrichment of central irisin and is sufficient to improve both the cognitive deficit and neuropathology in AD mouse models. Irisin is a crucial regulator of the cognitive benefits of exercise and is a potential therapeutic agent for treating cognitive disorders including AD.
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Affiliation(s)
- Mohammad R Islam
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Sophia Valaris
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Michael F Young
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Erin B Haley
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Renhao Luo
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Sabrina F Bond
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Behavioral Neuroscience, Northeastern University, Boston, MA, USA
| | - Sofia Mazuera
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Behavioral Neuroscience, Northeastern University, Boston, MA, USA
| | - Robert R Kitchen
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Barbara J Caldarone
- Harvard NeuroDiscovery Center, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Luis E B Bettio
- Division of Medical Sciences, University of Victoria, Victoria, British Colombia, Canada
| | - Brian R Christie
- Division of Medical Sciences, University of Victoria, Victoria, British Colombia, Canada
| | - Angela B Schmider
- Nephrology Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Roy J Soberman
- Nephrology Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Antoine Besnard
- Center for Regenerative Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Mark P Jedrychowski
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Hyeonwoo Kim
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Hua Tu
- LakePharma, San Carlos, CA, USA
| | - Eunhee Kim
- MassGeneral Institute for Neurodegenerative Disease, Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA, USA
| | - Se Hoon Choi
- MassGeneral Institute for Neurodegenerative Disease, Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA, USA
| | - Rudolph E Tanzi
- MassGeneral Institute for Neurodegenerative Disease, Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA, USA
| | - Bruce M Spiegelman
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Christiane D Wrann
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA, USA.
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14
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Baumert R, Ji H, Paulucci-Holthauzen A, Wolfe A, Sagum C, Hodgson L, Arikkath J, Chen X, Bedford MT, Waxham MN, McCrea PD. Novel phospho-switch function of delta-catenin in dendrite development. J Cell Biol 2021; 219:152151. [PMID: 33007084 PMCID: PMC7534926 DOI: 10.1083/jcb.201909166] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/27/2019] [Accepted: 08/21/2020] [Indexed: 11/22/2022] Open
Abstract
In neurons, dendrites form the major sites of information receipt and integration. It is thus vital that, during development, the dendritic arbor is adequately formed to enable proper neural circuit formation and function. While several known processes shape the arbor, little is known of those that govern dendrite branching versus extension. Here, we report a new mechanism instructing dendrites to branch versus extend. In it, glutamate signaling activates mGluR5 receptors to promote Ckd5-mediated phosphorylation of the C-terminal PDZ-binding motif of delta-catenin. The phosphorylation state of this motif determines delta-catenin's ability to bind either Pdlim5 or Magi1. Whereas the delta:Pdlim5 complex enhances dendrite branching at the expense of elongation, the delta:Magi1 complex instead promotes lengthening. Our data suggest that these complexes affect dendrite development by differentially regulating the small-GTPase RhoA and actin-associated protein Cortactin. We thus reveal a "phospho-switch" within delta-catenin, subject to a glutamate-mediated signaling pathway, that assists in balancing the branching versus extension of dendrites during neural development.
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Affiliation(s)
- Ryan Baumert
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX.,Program in Neuroscience, The University of Texas Graduate School of Biomedical Science, Houston, TX
| | - Hong Ji
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | | | - Aaron Wolfe
- Computational Biology and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA
| | - Cari Sagum
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX
| | - Louis Hodgson
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | | | - Xiaojiang Chen
- Computational Biology and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX.,Program in Genetics and Epigenetics, The University of Texas Graduate School of Biomedical Science, Houston, TX
| | - M Neal Waxham
- Program in Neuroscience, The University of Texas Graduate School of Biomedical Science, Houston, TX.,Department of Neurobiology and Anatomy, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX
| | - Pierre D McCrea
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX.,Program in Neuroscience, The University of Texas Graduate School of Biomedical Science, Houston, TX.,Program in Genetics and Epigenetics, The University of Texas Graduate School of Biomedical Science, Houston, TX
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15
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Cheng J, Scala F, Blanco FA, Niu S, Firozi K, Keehan L, Mulherkar S, Froudarakis E, Li L, Duman JG, Jiang X, Tolias KF. The Rac-GEF Tiam1 Promotes Dendrite and Synapse Stabilization of Dentate Granule Cells and Restricts Hippocampal-Dependent Memory Functions. J Neurosci 2021; 41:1191-1206. [PMID: 33328293 PMCID: PMC7888217 DOI: 10.1523/jneurosci.3271-17.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022] Open
Abstract
The dentate gyrus (DG) controls information flow into the hippocampus and is critical for learning, memory, pattern separation, and spatial coding, while DG dysfunction is associated with neuropsychiatric disorders. Despite its importance, the molecular mechanisms regulating DG neural circuit assembly and function remain unclear. Here, we identify the Rac-GEF Tiam1 as an important regulator of DG development and associated memory processes. In the hippocampus, Tiam1 is predominantly expressed in the DG throughout life. Global deletion of Tiam1 in male mice results in DG granule cells with simplified dendritic arbors, reduced dendritic spine density, and diminished excitatory synaptic transmission. Notably, DG granule cell dendrites and synapses develop normally in Tiam1 KO mice, resembling WT mice at postnatal day 21 (P21), but fail to stabilize, leading to dendrite and synapse loss by P42. These results indicate that Tiam1 promotes DG granule cell dendrite and synapse stabilization late in development. Tiam1 loss also increases the survival, but not the production, of adult-born DG granule cells, possibly because of greater circuit integration as a result of decreased competition with mature granule cells for synaptic inputs. Strikingly, both male and female mice lacking Tiam1 exhibit enhanced contextual fear memory and context discrimination. Together, these results suggest that Tiam1 is a key regulator of DG granule cell stabilization and function within hippocampal circuits. Moreover, based on the enhanced memory phenotype of Tiam1 KO mice, Tiam1 may be a potential target for the treatment of disorders involving memory impairments.SIGNIFICANCE STATEMENT The dentate gyrus (DG) is important for learning, memory, pattern separation, and spatial navigation, and its dysfunction is associated with neuropsychiatric disorders. However, the molecular mechanisms controlling DG formation and function remain elusive. By characterizing mice lacking the Rac-GEF Tiam1, we demonstrate that Tiam1 promotes the stabilization of DG granule cell dendritic arbors, spines, and synapses, whereas it restricts the survival of adult-born DG granule cells, which compete with mature granule cells for synaptic integration. Notably, mice lacking Tiam1 also exhibit enhanced contextual fear memory and context discrimination. These findings establish Tiam1 as an essential regulator of DG granule cell development, and identify it as a possible therapeutic target for memory enhancement.
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Affiliation(s)
- Jinxuan Cheng
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Federico Scala
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Francisco A Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, Texas 77030
| | - Sanyong Niu
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Laura Keehan
- Department of Biosciences, Rice University, Houston, Texas 77005
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | | | - Lingyong Li
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030
| | - Kimberley F Tolias
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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16
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Lin TY, Chen PJ, Yu HH, Hsu CP, Lee CH. Extrinsic Factors Regulating Dendritic Patterning. Front Cell Neurosci 2021; 14:622808. [PMID: 33519386 PMCID: PMC7838386 DOI: 10.3389/fncel.2020.622808] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022] Open
Abstract
Stereotypic dendrite arborizations are key morphological features of neuronal identity, as the size, shape and location of dendritic trees determine the synaptic input fields and how information is integrated within developed neural circuits. In this review, we focus on the actions of extrinsic intercellular communication factors and their effects on intrinsic developmental processes that lead to dendrite patterning. Surrounding neurons or supporting cells express adhesion receptors and secreted proteins that respectively, act via direct contact or over short distances to shape, size, and localize dendrites during specific developmental stages. The different ligand-receptor interactions and downstream signaling events appear to direct dendrite morphogenesis by converging on two categorical mechanisms: local cytoskeletal and adhesion modulation and global transcriptional regulation of key dendritic growth components, such as lipid synthesis enzymes. Recent work has begun to uncover how the coordinated signaling of multiple extrinsic factors promotes complexity in dendritic trees and ensures robust dendritic patterning.
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Affiliation(s)
- Tzu-Yang Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Pei-Ju Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Hung-Hsiang Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Chao-Ping Hsu
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chi-Hon Lee
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
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17
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Schöneberg T, Liebscher I. Mutations in G Protein-Coupled Receptors: Mechanisms, Pathophysiology and Potential Therapeutic Approaches. Pharmacol Rev 2020; 73:89-119. [PMID: 33219147 DOI: 10.1124/pharmrev.120.000011] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
There are approximately 800 annotated G protein-coupled receptor (GPCR) genes, making these membrane receptors members of the most abundant gene family in the human genome. Besides being involved in manifold physiologic functions and serving as important pharmacotherapeutic targets, mutations in 55 GPCR genes cause about 66 inherited monogenic diseases in humans. Alterations of nine GPCR genes are causatively involved in inherited digenic diseases. In addition to classic gain- and loss-of-function variants, other aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, pseudogenes, gene fusion, and gene dosage, contribute to the repertoire of GPCR dysfunctions. However, the spectrum of alterations and GPCR involvement is probably much larger because an additional 91 GPCR genes contain homozygous or hemizygous loss-of-function mutations in human individuals with currently unidentified phenotypes. This review highlights the complexity of genomic alteration of GPCR genes as well as their functional consequences and discusses derived therapeutic approaches. SIGNIFICANCE STATEMENT: With the advent of new transgenic and sequencing technologies, the number of monogenic diseases related to G protein-coupled receptor (GPCR) mutants has significantly increased, and our understanding of the functional impact of certain kinds of mutations has substantially improved. Besides the classical gain- and loss-of-function alterations, additional aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, uniparental disomy, pseudogenes, gene fusion, and gene dosage, need to be elaborated in light of GPCR dysfunctions and possible therapeutic strategies.
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Affiliation(s)
- Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
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18
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Vizurraga A, Adhikari R, Yeung J, Yu M, Tall GG. Mechanisms of adhesion G protein-coupled receptor activation. J Biol Chem 2020; 295:14065-14083. [PMID: 32763969 DOI: 10.1074/jbc.rev120.007423] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/31/2020] [Indexed: 12/19/2022] Open
Abstract
Adhesion G protein-coupled receptors (AGPCRs) are a thirty-three-member subfamily of Class B GPCRs that control a wide array of physiological processes and are implicated in disease. AGPCRs uniquely contain large, self-proteolyzing extracellular regions that range from hundreds to thousands of residues in length. AGPCR autoproteolysis occurs within the extracellular GPCR autoproteolysis-inducing (GAIN) domain that is proximal to the N terminus of the G protein-coupling seven-transmembrane-spanning bundle. GAIN domain-mediated self-cleavage is constitutive and produces two-fragment holoreceptors that remain bound at the cell surface. It has been of recent interest to understand how AGPCRs are activated in relation to their two-fragment topologies. Dissociation of the AGPCR fragments stimulates G protein signaling through the action of the tethered-peptide agonist stalk that is occluded within the GAIN domain in the holoreceptor form. AGPCRs can also signal independently of fragment dissociation, and a few receptors possess GAIN domains incapable of self-proteolysis. This has resulted in complex theories as to how these receptors are activated in vivo, complicating pharmacological advances. Currently, there is no existing structure of an activated AGPCR to support any of the theories. Further confounding AGPCR research is that many of the receptors remain orphans and lack identified activating ligands. In this review, we provide a detailed layout of the current theorized modes of AGPCR activation with discussion of potential parallels to mechanisms used by other GPCR classes. We provide a classification means for the ligands that have been identified and discuss how these ligands may activate AGPCRs in physiological contexts.
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Affiliation(s)
- Alexander Vizurraga
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Rashmi Adhikari
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Jennifer Yeung
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Maiya Yu
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
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19
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Ligon C, Seong E, Schroeder EJ, DeKorver NW, Yuan L, Chaudoin TR, Cai Y, Buch S, Bonasera SJ, Arikkath J. δ-Catenin engages the autophagy pathway to sculpt the developing dendritic arbor. J Biol Chem 2020; 295:10988-11001. [PMID: 32554807 DOI: 10.1074/jbc.ra120.013058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/14/2020] [Indexed: 01/21/2023] Open
Abstract
The development of the dendritic arbor in pyramidal neurons is critical for neural circuit function. Here, we uncovered a pathway in which δ-catenin, a component of the cadherin-catenin cell adhesion complex, promotes coordination of growth among individual dendrites and engages the autophagy mechanism to sculpt the developing dendritic arbor. Using a rat primary neuron model, time-lapse imaging, immunohistochemistry, and confocal microscopy, we found that apical and basolateral dendrites are coordinately sculpted during development. Loss or knockdown of δ-catenin uncoupled this coordination, leading to retraction of the apical dendrite without altering basolateral dendrite dynamics. Autophagy is a key cellular pathway that allows degradation of cellular components. We observed that the impairment of the dendritic arbor resulting from δ-catenin knockdown could be reversed by knockdown of autophagy-related 7 (ATG7), a component of the autophagy machinery. We propose that δ-catenin regulates the dendritic arbor by coordinating the dynamics of individual dendrites and that the autophagy mechanism may be leveraged by δ-catenin and other effectors to sculpt the developing dendritic arbor. Our findings have implications for the management of neurological disorders, such as autism and intellectual disability, that are characterized by dendritic aberrations.
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Affiliation(s)
- Cheryl Ligon
- Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Eunju Seong
- Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Ethan J Schroeder
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Nicholas W DeKorver
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Li Yuan
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Tammy R Chaudoin
- Division of Geriatrics, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Yu Cai
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Stephen J Bonasera
- Division of Geriatrics, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Jyothi Arikkath
- Department of Anatomy, Howard University, Washington, D. C., USA
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