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Cohen JD, Cadena del Castillo CE, Serra ND, Kaech A, Spang A, Sundaram MV. The Caenorhabditis elegans Patched domain protein PTR-4 is required for proper organization of the precuticular apical extracellular matrix. Genetics 2021; 219:iyab132. [PMID: 34740248 PMCID: PMC8570789 DOI: 10.1093/genetics/iyab132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/04/2021] [Indexed: 12/30/2022] Open
Abstract
The Patched-related superfamily of transmembrane proteins can transport lipids or other hydrophobic molecules across cell membranes. While the Hedgehog receptor Patched has been intensively studied, much less is known about the biological roles of other Patched-related family members. Caenorhabditis elegans has a large number of Patched-related proteins, despite lacking a canonical Hedgehog pathway. Here, we show that PTR-4 promotes the assembly of the precuticle apical extracellular matrix, a transient and molecularly distinct matrix that precedes and patterns the later collagenous cuticle or exoskeleton. ptr-4 mutants share many phenotypes with precuticle mutants, including defects in eggshell dissolution, tube shaping, alae (cuticle ridge) structure, molting, and cuticle barrier function. PTR-4 localizes to the apical side of a subset of outward-facing epithelia, in a cyclical manner that peaks when precuticle matrix is present. Finally, PTR-4 is required to limit the accumulation of the lipocalin LPR-3 and to properly localize the Zona Pellucida domain protein LET-653 within the precuticle. We propose that PTR-4 transports lipids or other hydrophobic components that help to organize the precuticle and that the cuticle and molting defects seen in ptr-4 mutants result at least in part from earlier disorganization of the precuticle.
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Affiliation(s)
- Jennifer D Cohen
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | | | - Nicholas D Serra
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zürich, 8006 Zürich, Switzerland
| | - Anne Spang
- Biozentrum, University of Basel, 4001 Basel, Switzerland
| | - Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
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2
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Walsh JD, Boivin O, Barr MM. What about the males? the C. elegans sexually dimorphic nervous system and a CRISPR-based tool to study males in a hermaphroditic species. J Neurogenet 2020; 34:323-334. [PMID: 32648491 PMCID: PMC7796903 DOI: 10.1080/01677063.2020.1789978] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/26/2020] [Indexed: 12/26/2022]
Abstract
Sexual dimorphism is a device that supports genetic diversity while providing selective pressure against speciation. This phenomenon is at the core of sexually reproducing organisms. Caenorhabditis elegans provides a unique experimental system where males exist in a primarily hermaphroditic species. Early works of John Sulston, Robert Horvitz, and John White provided a complete map of the hermaphrodite nervous system, and recently the male nervous system was added. This addition completely realized the vision of C. elegans pioneer Sydney Brenner: a model organism with an entirely mapped nervous system. With this 'connectome' of information available, great strides have been made toward understanding concepts such as how a sex-shared nervous system (in hermaphrodites and males) can give rise to sex-specific functions, how neural plasticity plays a role in developing a dimorphic nervous system, and how a shared nervous system receives and processes external cues in a sexually-dimorphic manner to generate sex-specific behaviors. In C. elegans, the intricacies of male-mating behavior have been crucial for studying the function and circuitry of the male-specific nervous system and used as a model for studying human autosomal dominant polycystic kidney disease (ADPKD). With the emergence of CRISPR, a seemingly limitless tool for generating genomic mutations with pinpoint precision, the C. elegans model system will continue to be a useful instrument for pioneering research in the fields of behavior, reproductive biology, and neurogenetics.
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Affiliation(s)
- Jonathon D Walsh
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Olivier Boivin
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
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3
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Riveiro AR, Mariani L, Malmberg E, Amendola PG, Peltonen J, Wong G, Salcini AE. JMJD-1.2/PHF8 controls axon guidance by regulating Hedgehog-like signaling. Development 2017; 144:856-865. [PMID: 28126843 DOI: 10.1242/dev.142695] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 01/09/2017] [Indexed: 01/10/2023]
Abstract
Components of the KDM7 family of histone demethylases are implicated in neuronal development and one member, PHF8, is often found to be mutated in cases of X-linked mental retardation. However, how PHF8 regulates neurodevelopmental processes and contributes to the disease is still largely unknown. Here, we show that the catalytic activity of a PHF8 homolog in Caenorhabditis elegans, JMJD-1.2, is required non-cell-autonomously for proper axon guidance. Loss of JMJD-1.2 dysregulates transcription of the Hedgehog-related genes wrt-8 and grl-16, the overexpression of which is sufficient to induce the axonal defects. Deficiency of either wrt-8 or grl-16, or reduced expression of homologs of genes promoting Hedgehog signaling, restores correct axon guidance in jmjd-1.2 mutants. Genetic and overexpression data indicate that Hedgehog-related genes act on axon guidance through actin remodelers. Thus, our study highlights a novel function of jmjd-1.2 in axon guidance that might be relevant for the onset of X-linked mental retardation and provides compelling evidence of a conserved function of the Hedgehog pathway in C. elegans axon migration.
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Affiliation(s)
- Alba Redo Riveiro
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Copenhagen, Denmark.,Centre for Epigenetics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Luca Mariani
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Copenhagen, Denmark.,Centre for Epigenetics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Emily Malmberg
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Copenhagen, Denmark.,Centre for Epigenetics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Pier Giorgio Amendola
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Copenhagen, Denmark.,Centre for Epigenetics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Juhani Peltonen
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, 70211, Kuopio, Finland
| | - Garry Wong
- Faculty of Health Sciences, University of Macau, 999078, Macau, China
| | - Anna Elisabetta Salcini
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Copenhagen, Denmark .,Centre for Epigenetics, University of Copenhagen, 2200, Copenhagen, Denmark
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4
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Beer KB, Wehman AM. Mechanisms and functions of extracellular vesicle release in vivo-What we can learn from flies and worms. Cell Adh Migr 2016; 11:135-150. [PMID: 27689411 PMCID: PMC5351733 DOI: 10.1080/19336918.2016.1236899] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cells from bacteria to man release extracellular vesicles (EVs) that contain signaling molecules like proteins, lipids, and nucleic acids. The content, formation, and signaling roles of these conserved vesicles are diverse, but the physiological relevance of EV signaling in vivo is still debated. Studies in classical genetic model organisms like C. elegans and Drosophila have begun to reveal the developmental and behavioral roles for EVs. In this review, we discuss the emerging evidence for the in vivo signaling roles of EVs. Significant effort has also been made to understand the mechanisms behind the formation and release of EVs, specifically of exosomes derived from exocytosis of multivesicular bodies and of microvesicles derived from plasma membrane budding called ectocytosis. In this review, we detail the impact of flies and worms on understanding the proteins and lipids involved in EV biogenesis and highlight the open questions in the field.
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Affiliation(s)
- Katharina B Beer
- a Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg , Würzburg , Germany
| | - Ann Marie Wehman
- a Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg , Würzburg , Germany
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6
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Erives AJ. Genes conserved in bilaterians but jointly lost with Myc during nematode evolution are enriched in cell proliferation and cell migration functions. Dev Genes Evol 2015; 225:259-73. [PMID: 26173873 PMCID: PMC4568025 DOI: 10.1007/s00427-015-0508-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/24/2015] [Indexed: 12/11/2022]
Abstract
Animals use a stereotypical set of developmental genes to build body architectures of varying sizes and organizational complexity. Some genes are critical to developmental patterning, while other genes are important to physiological control of growth. However, growth regulator genes may not be as important in small-bodied “micro-metazoans” such as nematodes. Nematodes use a simplified developmental strategy of lineage-based cell fate specifications to produce an adult bilaterian body composed of a few hundreds of cells. Nematodes also lost the MYC proto-oncogenic regulator of cell proliferation. To identify additional regulators of cell proliferation that were lost with MYC, we computationally screened and determined 839 high-confidence genes that are conserved in bilaterians/lost in nematodes (CIBLIN genes). We find that 30 % of all CIBLIN genes encode transcriptional regulators of cell proliferation, epithelial-to-mesenchyme transitions, and other processes. Over 50 % of CIBLIN genes are unnamed genes in Drosophila, suggesting that there are many understudied genes. Interestingly, CIBLIN genes include many Myc synthetic lethal (MycSL) hits from recent screens. CIBLIN genes include key regulators of heparan sulfate proteoglycan (HSPG) sulfation patterns, and lysyl oxidases involved in cross-linking and modification of the extracellular matrix (ECM). These genes and others suggest the CIBLIN repertoire services critical functions in ECM remodeling and cell migration in large-bodied bilaterians. Correspondingly, CIBLIN genes are co-expressed with Myc in cancer transcriptomes, and include a preponderance of known determinants of cancer progression and tumor aggression. We propose that CIBLIN gene research can improve our understanding of regulatory control of cellular growth in metazoans.
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Affiliation(s)
- Albert J Erives
- Department of Biology, University of Iowa, Iowa City, IA, 52242-1324, USA.
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7
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Mellado M, Cuartero Y, Brugada R, Verges M. Subcellular localisation of retromer in post-endocytic pathways of polarised Madin-Darby canine kidney cells. Biol Cell 2014; 106:377-93. [PMID: 25081925 DOI: 10.1111/boc.201400011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/28/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND INFORMATION Retromer is required for endosome-to-Golgi retrieval of the cation-independent mannose 6-phosphate receptor (CI-MPR), allowing delivery of hydrolases into lysosomes. It is constituted by a conserved heterotrimer formed by vacuolar protein sorting (Vps) gene products Vps26, Vps35 and Vps29, which is in charge of cargo selection, and a dimer of phosphoinositide-binding sorting nexins (SNXs), which has a structural role. Retromer has been implicated in sorting of additional cargo. Thus, retromer also promotes polymeric immunoglobulin A (pIgA) transcytosis by the pIgA receptor (pIgR) in polarised cells, and considerable evidence implicates retromer in controlling epithelial cell polarity. However, the precise localisation of retromer along the endocytic pathway of polarised cells has not been studied in detail. RESULTS Our biochemical analysis using rat liver endosome fractions suggests a distinct distribution pattern. Although subunits of the cargo-selective complex were enriched in early endosomes (EEs), levels of SNX2 were greater in sorting endosomes. We then immunolocalised the retromer subunits in polarised Madin-Darby canine kidney (MDCK) cells by confocal microscopy. An estimated 25% of total Vps26 and SNX2 localised to EEs, with negligible portions in recycling endosomes as well as in late endosomes and lysosomes. Although Vps26 was in structures of more heterogeneous size and shape than SNX2, these markedly overlapped. In consequence, the two retromer subcomplexes mostly colocalised. When we analysed retromer overlap with its cargo, we found that structures retromer and pIgA(+) are independent of those structures retromer and CI-MPR(+) . Remarkably, retromer localised preferentially at the transcytotic pathway. Pharmacological inhibition of phosphoinositide 3-kinase affected the co-distribution of retromer with pIgA and the CI-MPR, delaying pIgA progress to the apical surface. CONCLUSIONS In polarised MDCK cells, we found retromer associated with certain specialised EE-derived pathways. Our data imply that retromer is largely engaged in pIgA transcytosis in pIgR-expressing MDCK cells, as opposed to endosome-to-Golgi retrieval.
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Affiliation(s)
- Maravillas Mellado
- Laboratory of Epithelial Cell Biology, Príncipe Felipe Research Center (CIPF), Valencia, 46012, Spain
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8
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Armstrong SD, Babayan SA, Lhermitte-Vallarino N, Gray N, Xia D, Martin C, Kumar S, Taylor DW, Blaxter ML, Wastling JM, Makepeace BL. Comparative analysis of the secretome from a model filarial nematode (Litomosoides sigmodontis) reveals maximal diversity in gravid female parasites. Mol Cell Proteomics 2014; 13:2527-44. [PMID: 24958169 DOI: 10.1074/mcp.m114.038539] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Filarial nematodes (superfamily Filarioidea) are responsible for an annual global health burden of ∼6.3 million disability-adjusted life-years, which represents the greatest single component of morbidity attributable to helminths affecting humans. No vaccine exists for the major filarial diseases, lymphatic filariasis and onchocerciasis; in part because research on protective immunity against filariae has been constrained by the inability of the human-parasitic species to complete their lifecycles in laboratory mice. However, the rodent filaria Litomosoides sigmodontis has become a popular experimental model, as BALB/c mice are fully permissive for its development and reproduction. Here, we provide a comprehensive analysis of excretory-secretory products from L. sigmodontis across five lifecycle stages and identifications of host proteins associated with first-stage larvae (microfilariae) in the blood. Applying intensity-based quantification, we determined the abundance of 302 unique excretory-secretory proteins, of which 64.6% were present in quantifiable amounts only from gravid adult female nematodes. This lifecycle stage, together with immature microfilariae, released four proteins that have not previously been evaluated as vaccine candidates: a predicted 28.5 kDa filaria-specific protein, a zonadhesin and SCO-spondin-like protein, a vitellogenin, and a protein containing six metridin-like ShK toxin domains. Female nematodes also released two proteins derived from the obligate Wolbachia symbiont. Notably, excretory-secretory products from all parasite stages contained several uncharacterized members of the transthyretin-like protein family. Furthermore, biotin labeling revealed that redox proteins and enzymes involved in purinergic signaling were enriched on the adult nematode cuticle. Comparison of the L. sigmodontis adult secretome with that of the human-infective filarial nematode Brugia malayi (reported previously in three independent published studies) identified differences that suggest a considerable underlying diversity of potential immunomodulators. The molecules identified in L. sigmodontis excretory-secretory products show promise not only for vaccination against filarial infections, but for the amelioration of allergy and autoimmune diseases.
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Affiliation(s)
- Stuart D Armstrong
- From the ‡Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK
| | - Simon A Babayan
- §Centre for Immunity, Infection & Evolution and Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
| | | | - Nick Gray
- §Centre for Immunity, Infection & Evolution and Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Dong Xia
- From the ‡Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK
| | - Coralie Martin
- ¶UMR 7245 MCAM CNRS, Muséum National d'Histoire Naturelle, 75231 Paris, France
| | - Sujai Kumar
- §Centre for Immunity, Infection & Evolution and Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - David W Taylor
- ‖Division of Pathway Medicine, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Mark L Blaxter
- §Centre for Immunity, Infection & Evolution and Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Jonathan M Wastling
- From the ‡Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK; **The National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool L3 5RF, UK
| | - Benjamin L Makepeace
- From the ‡Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK;
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9
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Aitlhadj L, Stürzenbaum SR. Caenorhabditis elegans in regenerative medicine: a simple model for a complex discipline. Drug Discov Today 2014; 19:730-4. [PMID: 24513577 DOI: 10.1016/j.drudis.2014.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/21/2014] [Accepted: 01/28/2014] [Indexed: 10/25/2022]
Abstract
Stem cell research is a major focus of regenerative medicine, which amalgamates diverse disciplines ranging from developmental cell biology to chemical and genetic therapy. Although embryonic stem cells have provided the foundation of stem cell therapy, they offer an in vitro study system that might not provide the best insight into mechanisms and behaviour of cells within living organisms. Caenorhabditis elegans is a well defined model organism with highly conserved cell development and signalling processes that specify cell fate. Its genetic amenability coupled with its chemical screening applicability make the nematode well suited as an in vivo system in which regenerative therapy and stem cell processes can be explored. Here, we describe some of the major advances in stem cell research from the worm's perspective.
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Affiliation(s)
- Layla Aitlhadj
- King's College London, School of Biomedical Sciences, Analytical and Environmental Sciences Division, London SE1 9NH, UK; Kinǵs College London, School of Biomedical Sciences, MRC-PHE Centre for Environment & Health, London, SE1 9NH, UK
| | - Stephen R Stürzenbaum
- King's College London, School of Biomedical Sciences, Analytical and Environmental Sciences Division, London SE1 9NH, UK; Kinǵs College London, School of Biomedical Sciences, MRC-PHE Centre for Environment & Health, London, SE1 9NH, UK.
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10
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van den Boorn JG, Dassler J, Coch C, Schlee M, Hartmann G. Exosomes as nucleic acid nanocarriers. Adv Drug Deliv Rev 2013; 65:331-5. [PMID: 22750807 DOI: 10.1016/j.addr.2012.06.011] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 06/20/2012] [Indexed: 12/21/2022]
Abstract
Exosomes are nano-sized vesicles produced naturally by many cell types. They are specifically loaded with nucleic acid cargo, dependent on the exosome-producing cell and its homeostatic state. As natural intercellular shuttles of miRNA, exosomes influence an array of developmental, physiological and pathological processes in the recipient cell or tissue to which they can be selectively targeted by their tetraspanin surface-domains. By a review of current research, we illustrate here why exosomes are ideal nanocarriers for use in the targeted in vivo delivery of nucleic acids.
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Affiliation(s)
- Jasper G van den Boorn
- Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany.
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11
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Morel L, Regan M, Higashimori H, Ng SK, Esau C, Vidensky S, Rothstein J, Yang Y. Neuronal exosomal miRNA-dependent translational regulation of astroglial glutamate transporter GLT1. J Biol Chem 2013; 288:7105-16. [PMID: 23364798 DOI: 10.1074/jbc.m112.410944] [Citation(s) in RCA: 285] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Perisynaptic astrocytes express important glutamate transporters, especially excitatory amino acid transporter 2 (EAAT2, rodent analog GLT1) to regulate extracellular glutamate levels and modulate synaptic activation. In this study, we investigated an exciting new pathway, the exosome-mediated transfer of microRNA (in particular, miR-124a), in neuron-to-astrocyte signaling. Exosomes isolated from neuron-conditioned medium contain abundant microRNAs and small RNAs. These exosomes can be directly internalized into astrocytes and increase astrocyte miR-124a and GLT1 protein levels. Direct miR-124a transfection also significantly and selectively increases protein (but not mRNA) expression levels of GLT1 in cultured astrocytes. Consistent with our in vitro findings, intrastriatal injection of specific antisense against miR-124a into adult mice dramatically reduces GLT1 protein expression and glutamate uptake levels in striatum without reducing GLT1 mRNA levels. MiR-124a-mediated regulation of GLT1 expression appears to be indirect and is not mediated by its suppression of the putative GLT1 inhibitory ligand ephrinA3. Moreover, miR-124a is selectively reduced in the spinal cord tissue of end-stage SOD1 G93A mice, the mouse model of ALS. Subsequent exogenous delivery of miR-124a in vivo through stereotaxic injection significantly prevents further pathological loss of GLT1 proteins, as determined by GLT1 immunoreactivity in SOD1 G93A mice. Together, our study characterized a new neuron-to-astrocyte communication pathway and identified miRNAs that modulate GLT1 protein expression in astrocytes in vitro and in vivo.
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Affiliation(s)
- Lydie Morel
- Department of Neuroscience, Tufts University, Boston, Massachusetts 02111, USA
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Chisholm AD, Xu S. The Caenorhabditis elegans epidermis as a model skin. II: differentiation and physiological roles. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 1:879-902. [PMID: 23539358 DOI: 10.1002/wdev.77] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The Caenorhabditis elegans epidermis forms one of the principal barrier epithelia of the animal. Differentiation of the epidermis begins in mid embryogenesis and involves apical-basal polarization of the cytoskeletal and secretory systems as well as cellular junction formation. Secretion of the external cuticle layers is one of the major developmental and physiological specializations of the epidermal epithelium. The four post-embryonic larval stages are separated by periodic moults, in which the epidermis generates a new cuticle with stage-specific characteristics. The differentiated epidermis also plays key roles in endocrine signaling, fat storage, and ionic homeostasis. The epidermis is intimately associated with the development and function of the nervous system, and may have glial-like roles in modulating neuronal function. The epidermis provides passive and active defenses against skin-penetrating pathogens and can repair small wounds. Finally, age-dependent deterioration of the epidermis is a prominent feature of aging and may affect organismal aging and lifespan.
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Affiliation(s)
- Andrew D Chisholm
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.
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Turola E, Furlan R, Bianco F, Matteoli M, Verderio C. Microglial microvesicle secretion and intercellular signaling. Front Physiol 2012; 3:149. [PMID: 22661954 PMCID: PMC3357554 DOI: 10.3389/fphys.2012.00149] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 05/02/2012] [Indexed: 01/02/2023] Open
Abstract
Microvesicles (MVs) are released from almost all cell brain types into the microenvironment and are emerging as a novel way of cell-to-cell communication. This review focuses on MVs discharged by microglial cells, the brain resident myeloid cells, which comprise ∼10–12% of brain population. We summarize first evidence indicating that MV shedding is a process activated by the ATP receptor P2X7 and that shed MVs represent a secretory pathway for the inflammatory cytokine IL-β. We then discuss subsequent findings which clarify how IL-1 β can be locally processed and released from MVs into the extracellular environment. In addition, we describe the current understanding about the mechanism of P2X7-dependent MV formation and membrane abscission, which, by involving sphingomyelinase activity and ceramide formation, may share similarities with exosome biogenesis. Finally we report our recent results which show that microglia-derived MVs can stimulate neuronal activity and participate to the propagation of inflammatory signals, and suggest new areas for future investigation.
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Koles K, Nunnari J, Korkut C, Barria R, Brewer C, Li Y, Leszyk J, Zhang B, Budnik V. Mechanism of evenness interrupted (Evi)-exosome release at synaptic boutons. J Biol Chem 2012; 287:16820-34. [PMID: 22437826 DOI: 10.1074/jbc.m112.342667] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Wnt signaling plays critical roles during synaptic development and plasticity. However, the mechanisms by which Wnts are released and travel to target cells are unresolved. During synaptic development, the secretion of Drosophila Wnt1, Wingless, requires the function of Evenness Interrupted (Evi)/Wls, a Wingless-binding protein that is secreted along with Wingless at the neuromuscular junction. Given that Evi is a transmembrane protein, these studies suggested the presence of a novel vesicular mechanism of trans-synaptic communication, potentially in the form of exosomes. To establish the mechanisms for the release of Evi vesicles, we used a dsRNA assay in cultured cells to screen for genes that when down-regulated prevent the release of Evi vesicles. We identified two proteins, Rab11 and Syntaxin 1A (Syx1A), that were required for Evi vesicle release. To determine whether the same mechanisms were used in vivo at the neuromuscular junction, we altered the activity of Rab11 and Syx1A in motoneurons and determined the impact on Evi release. We found that Syx1A, Rab11, and its effector Myosin5 were required for proper Evi vesicle release. Furthermore, ultrastructural analysis of synaptic boutons demonstrated the presence of multivesicular bodies, organelles involved in the production and release of exosomes, and these multivesicular bodies contained Evi. We also used mass spectrometry, electron microscopy, and biochemical techniques to characterize the exosome fraction from cultured cells. Our studies revealed that secreted Evi vesicles show remarkable conservation with exosomes in other systems. In summary, our observations unravel some of the in vivo mechanisms required for Evi vesicle release.
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Affiliation(s)
- Kate Koles
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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15
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Meister P, Schott S, Bedet C, Xiao Y, Rohner S, Bodennec S, Hudry B, Molin L, Solari F, Gasser SM, Palladino F. Caenorhabditis elegans Heterochromatin protein 1 (HPL-2) links developmental plasticity, longevity and lipid metabolism. Genome Biol 2011; 12:R123. [PMID: 22185090 PMCID: PMC3334618 DOI: 10.1186/gb-2011-12-12-r123] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 11/30/2011] [Accepted: 12/20/2011] [Indexed: 01/23/2023] Open
Abstract
Background Heterochromatin protein 1 (HP1) family proteins have a well-characterized role in heterochromatin packaging and gene regulation. Their function in organismal development, however, is less well understood. Here we used genome-wide expression profiling to assess novel functions of the Caenorhabditis elegans HP1 homolog HPL-2 at specific developmental stages. Results We show that HPL-2 regulates the expression of germline genes, extracellular matrix components and genes involved in lipid metabolism. Comparison of our expression data with HPL-2 ChIP-on-chip profiles reveals that a significant number of genes up- and down-regulated in the absence of HPL-2 are bound by HPL-2. Germline genes are specifically up-regulated in hpl-2 mutants, consistent with the function of HPL-2 as a repressor of ectopic germ cell fate. In addition, microarray results and phenotypic analysis suggest that HPL-2 regulates the dauer developmental decision, a striking example of phenotypic plasticity in which environmental conditions determine developmental fate. HPL-2 acts in dauer at least partly through modulation of daf-2/IIS and TGF-β signaling pathways, major determinants of the dauer program. hpl-2 mutants also show increased longevity and altered lipid metabolism, hallmarks of the long-lived, stress resistant dauers. Conclusions Our results suggest that the worm HP1 homologue HPL-2 may coordinately regulate dauer diapause, longevity and lipid metabolism, three processes dependent on developmental input and environmental conditions. Our findings are of general interest as a paradigm of how chromatin factors can both stabilize development by buffering environmental variation, and guide the organism through remodeling events that require plasticity of cell fate regulation.
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Affiliation(s)
- Peter Meister
- Laboratory of Molecular and Cellular Biology, CNRS, Université de Lyon, Ecole Normale Supérieure, Lyon Cedex 07, France
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Shen B, Wu N, Yang JM, Gould SJ. Protein targeting to exosomes/microvesicles by plasma membrane anchors. J Biol Chem 2011; 286:14383-95. [PMID: 21300796 PMCID: PMC3077638 DOI: 10.1074/jbc.m110.208660] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/25/2011] [Indexed: 12/14/2022] Open
Abstract
Animal cells secrete small vesicles, otherwise known as exosomes and microvesicles (EMVs). A short, N-terminal acylation tag can target a highly oligomeric cytoplasmic protein, TyA, into secreted vesicles (Fang, Y., Wu, N., Gan, X., Yan, W., Morell, J. C., and Gould, S. J. (2007) PLoS Biol. 5, 1267-1283). However, it is not clear whether this is true for other membrane anchors or other highly oligomeric, cytoplasmic proteins. We show here that a variety of plasma membrane anchors can target TyA-GFP to sites of vesicle budding and into EMVs, including: (i) a myristoylation tag; (ii) a phosphatidylinositol-(4,5)-bisphosphate (PIP(2))-binding domain; (iii), a phosphatidylinositol-(3,4,5)-trisphosphate-binding domain; (iv) a prenylation/palmitoylation tag, and (v) a type-1 plasma membrane protein, CD43. However, the relative budding efficiency induced by these plasma membrane anchors varied over a 10-fold range, from 100% of control (AcylTyA-GFP) for the myristoylation tag and PIP(2)-binding domain, to one-third or less for the others, respectively. Targeting TyA-GFP to endosome membranes by fusion to a phosphatidylinositol 3-phosphate-binding domain induced only a slight budding of TyA-GFP, ∼2% of control, and no budding was observed when TyA-GFP was targeted to Golgi membranes via a phosphatidylinositol 4-phosphate-binding domain. We also found that a plasma membrane anchor can target two other highly oligomeric, cytoplasmic proteins to EMVs. These observations support the hypothesis that plasma membrane anchors can target highly oligomeric, cytoplasmic proteins to EMVs. Our data also provide additional parallels between EMV biogenesis and retrovirus budding, as the anchors that induced the greatest budding of TyA-GFP are the same as those that mediate retrovirus budding.
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Affiliation(s)
- Beiyi Shen
- From the Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Ning Wu
- From the Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Jr-Ming Yang
- From the Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Stephen J. Gould
- From the Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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Gallet A. Hedgehog morphogen: from secretion to reception. Trends Cell Biol 2011; 21:238-46. [PMID: 21257310 DOI: 10.1016/j.tcb.2010.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 12/08/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
Abstract
A major challenge of developmental biology is to understand how cells coordinate developmental behaviors with their neighbors. To achieve this, cells often employ signaling molecules that emanate from a local source and act at a distance on target cells. The Hedgehog morphogen is an essential signaling molecule required for numerous processes during animal development. Emphasizing the importance of this molecule for both growth control and patterning, Hedgehog signaling activity is often deregulated during cancer formation and progression. The secretion and spread of Hedgehog are not passive processes, but require accessory molecules involved in Hedgehog processing, release, spread and reception. In this review, I focus on the factors that are required to control the spread and activity of Hedgehog, highlighting recent data that have shed light on these processes.
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Affiliation(s)
- Armel Gallet
- Institut de Biologie du Développement & Cancer - IBDC, Université de Nice Sophia-Antipolis, UMR6543 CNRS, Centre de Biochimie, Parc Valrose, 06108 Nice cedex 2, France.
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Gan X, Gould SJ. Identification of an inhibitory budding signal that blocks the release of HIV particles and exosome/microvesicle proteins. Mol Biol Cell 2011; 22:817-30. [PMID: 21248205 PMCID: PMC3057706 DOI: 10.1091/mbc.e10-07-0625] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We identify and characterize an inhibitory budding signal that acts dominantly to block the budding of otherwise budding-competent proteins, both viral and nonviral, and impairs the budding of several classic, budding-deficient HIV mutants. These findings expand our understanding of EMV biogenesis and resolve a number of previously paradoxical observations regarding the budding of HIV. Animal cells bud exosomes and microvesicles (EMVs) from endosome and plasma membranes. The combination of higher-order oligomerization and plasma membrane binding is a positive budding signal that targets diverse proteins into EMVs and retrovirus particles. Here we describe an inhibitory budding signal (IBS) from the human immunodeficiency virus (HIV) Gag protein. This IBS was identified in the spacer peptide 2 (SP2) domain of Gag, is activated by C-terminal exposure of SP2, and mediates the severe budding defect of p6-deficient and PTAP-deficient strains of HIV. This IBS also impairs the budding of CD63 and several other viral and nonviral EMV proteins. The IBS does not prevent cargo delivery to the plasma membrane, a major site of EMV and virus budding. However, the IBS does inhibit an interaction between EMV cargo proteins and VPS4B, a component of the endosomal sorting complexes required for transport (ESCRT) machinery. Taken together, these results demonstrate that inhibitory signals can block protein and virus budding, raise the possibility that the ESCRT machinery plays a role in EMV biogenesis, and shed new light on the role of the p6 domain and PTAP motif in the biogenesis of HIV particles.
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Affiliation(s)
- Xin Gan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Williamson WR, Wang D, Haberman AS, Hiesinger PR. A dual function of V0-ATPase a1 provides an endolysosomal degradation mechanism in Drosophila melanogaster photoreceptors. ACTA ACUST UNITED AC 2010; 189:885-99. [PMID: 20513768 PMCID: PMC2878941 DOI: 10.1083/jcb.201003062] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A vesicular ATPase regulates both vesicle fusion and subsequent acidification of a subset of neuronal lysosomes and autophagosomes. The vesicular adenosine triphosphatase (v-ATPase) is a proton pump that acidifies intracellular compartments. In addition, mutations in components of the membrane-bound v-ATPase V0 sector cause acidification-independent defects in yeast, worm, fly, zebrafish, and mouse. In this study, we present a dual function for the neuron-specific V0 subunit a1 orthologue v100 in Drosophila melanogaster. A v100 mutant that selectively disrupts proton translocation rescues a previously characterized synaptic vesicle fusion defect and vesicle fusion with early endosomes. Correspondingly, V100 selectively interacts with syntaxins on the respective target membranes, and neither synaptic vesicles nor early endosomes require v100 for their acidification. In contrast, V100 is required for acidification once endosomes mature into degradative compartments. As a consequence of the complete loss of this neuronal degradation mechanism, photoreceptors undergo slow neurodegeneration, whereas selective rescue of the acidification-independent function accelerates cell death by increasing accumulations in degradation-incompetent compartments. We propose that V100 exerts a temporally integrated dual function that increases neuronal degradative capacity.
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Affiliation(s)
- W Ryan Williamson
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Fürthauer M, González-Gaitán M. Tales of 1001 functions: the multiple roles of membrane trafficking in development. Traffic 2009; 10:781-2. [PMID: 19570190 DOI: 10.1111/j.1600-0854.2009.00931.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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