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Sundaram MV, Pujol N. The Caenorhabditis elegans cuticle and precuticle: a model for studying dynamic apical extracellular matrices in vivo. Genetics 2024:iyae072. [PMID: 38995735 DOI: 10.1093/genetics/iyae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/25/2024] [Indexed: 07/14/2024] Open
Abstract
Apical extracellular matrices (aECMs) coat the exposed surfaces of animal bodies to shape tissues, influence social interactions, and protect against pathogens and other environmental challenges. In the nematode Caenorhabditis elegans, collagenous cuticle and zona pellucida protein-rich precuticle aECMs alternately coat external epithelia across the molt cycle and play many important roles in the worm's development, behavior, and physiology. Both these types of aECMs contain many matrix proteins related to those in vertebrates, as well as some that are nematode-specific. Extensive differences observed among tissues and life stages demonstrate that aECMs are a major feature of epithelial cell identity. In addition to forming discrete layers, some cuticle components assemble into complex substructures such as ridges, furrows, and nanoscale pillars. The epidermis and cuticle are mechanically linked, allowing the epidermis to sense cuticle damage and induce protective innate immune and stress responses. The C. elegans model, with its optical transparency, facilitates the study of aECM cell biology and structure/function relationships and all the myriad ways by which aECM can influence an organism.
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Affiliation(s)
- Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Nathalie Pujol
- Aix Marseille University, INSERM, CNRS, CIML, Turing Centre for Living Systems, 13009 Marseille, France
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Ragle JM, Turzo A, Levenson MT, Jonnalagadda K, Jackson A, Vo AA, Pham VT, Ward JD. MLT-11 is a transient apical extracellular matrix component required for cuticle patterning and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.12.593762. [PMID: 38766248 PMCID: PMC11100798 DOI: 10.1101/2024.05.12.593762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Apical extracellular matrices (aECMs) are associated with all epithelia and form a protective layer against biotic and abiotic threats in the environment. Despite their importance, we lack a deep understanding of their structure and dynamics in development and disease. C. elegans molting offers a powerful entry point to understanding developmentally programmed aECM remodeling. A transient matrix is formed in embryos and at the end of each larval stage, presumably to pattern the new cuticle. Focusing on targets of NHR-23, a key transcription factor which drives molting, we identified the Kunitz family protease inhibitor gene mlt-11 as an NHR-23 target. We identified NHR-23-binding sites that are necessary and sufficient for epithelial expression. mlt-11 is necessary to pattern every layer of the adult cuticle, suggesting a broad patterning role prior to the formation of the mature cuticle. MLT-11::mNeonGreen::3xFLAG transiently localized to the aECM in the cuticle and embryo. It was also detected in lining openings to the exterior (vulva, rectum, mouth). Reduction of mlt-11 function disrupted the barrier function of the cuticle. Tissue-specific RNAi suggested mlt-11 activity is primarily necessary in seam cells and we observed alae and seam cell fusion defects upon mlt-11 inactivation. Predicted mlt-11 null mutations caused fully penetrant embryonic lethality and elongation defects suggesting mlt-11 also plays an important role in patterning the embryonic sheath. Finally, we found that mlt-11 inactivation suppressed the blistered cuticle phenotype of mutants of bli-4 mutants, a subtilisin protease gene but did not affect BLI-4::sfGFP expression. These data could suggest that MLT-11 may be necessary to assure proper levels of BLI-4 activity.
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Affiliation(s)
- James Matthew Ragle
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Ariela Turzo
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Max T. Levenson
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Keya Jonnalagadda
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Anton Jackson
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - An A. Vo
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Vivian T. Pham
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jordan D. Ward
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
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Binti S, Edeen PT, Fay DS. Loss of the Na + /K + cation pump CATP-1 suppresses nekl -associated molting defects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.15.585189. [PMID: 38559007 PMCID: PMC10979969 DOI: 10.1101/2024.03.15.585189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The conserved C. elegans protein kinases NEKL-2 and NEKL-3 regulate multiple steps of membrane trafficking and are required for larval molting. Through a forward genetic screen we identified a loss-of-function mutation in catp-1 as a suppressor of molting defects in synthetically lethal nekl-2; nekl-3 double mutants. catp-1 is predicted to encode a membrane- associated P4-type ATPase involved in Na + -K + exchange. Moreover, a mutation predicted to abolish CATP-1 ion-pump activity also suppressed nekl-2; nekl-3 mutants. Endogenously tagged CATP-1 was primarily expressed in epidermal (hypodermal) cells within punctate structures located at or near the apical plasma membrane. Through whole genome sequencing, we identified two additional nekl-2; nekl-3 suppressor strains containing coding-altering mutations in catp-1 but found that neither mutation, when introduced into nekl-2; nekl-3 mutants using CRISPR methods, was sufficient to elicit robust suppression of molting defects. Our data also suggested that the two catp-1 isoforms, catp-1a and catp-1b , may in some contexts be functionally redundant. On the basis of previously published studies, we tested the hypothesis that loss of catp-1 may suppress nekl -associated defects by inducing partial entry into the dauer pathway. Contrary to expectations, however, we failed to obtain evidence that loss of catp-1 suppresses nekl-2; nekl-3 defects through a dauer-associated mechanism or that loss of catp-1 leads to entry into the pre-dauer L2d stage. As such, loss of catp-1 may suppress nekl- associated molting and membrane trafficking defects by altering electrochemical gradients within membrane-bound compartments.
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Serra ND, Darwin CB, Sundaram MV. C. elegans Hedgehog-related proteins are tissue- and substructure-specific components of the cuticle and pre-cuticle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.26.573316. [PMID: 38234847 PMCID: PMC10793445 DOI: 10.1101/2023.12.26.573316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
In C. elegans, divergent Hedgehog-related (Hh-r) and Patched-related (PTR) proteins promote numerous processes ranging from epithelial and sense organ development to pathogen responses to cuticle shedding during the molt cycle. Here we show that Hh-r proteins are actual components of the cuticle and pre-cuticle apical extracellular matrices (aECMs) that coat, shape, and protect external epithelia. Different Hh-r proteins stably associate with the aECMs of specific tissues and with specific substructures such as furrows and alae. Hh-r mutations can disrupt matrix structure. These results provide a unifying model for the function of nematode Hh-r proteins and highlight ancient connections between Hh proteins and the extracellular matrix.
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Affiliation(s)
- Nicholas D. Serra
- Dept. of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Chelsea B. Darwin
- Dept. of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Meera V. Sundaram
- Dept. of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
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Birnbaum SK, Cohen JD, Belfi A, Murray JI, Adams JRG, Chisholm AD, Sundaram MV. The proprotein convertase BLI-4 promotes collagen secretion prior to assembly of the Caenorhabditis elegans cuticle. PLoS Genet 2023; 19:e1010944. [PMID: 37721936 PMCID: PMC10538796 DOI: 10.1371/journal.pgen.1010944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/28/2023] [Accepted: 08/30/2023] [Indexed: 09/20/2023] Open
Abstract
Some types of collagens, including transmembrane MACIT collagens and C. elegans cuticle collagens, are N-terminally cleaved at a dibasic site that resembles the consensus for furin or other proprotein convertases of the subtilisin/kexin (PCSK) family. Such cleavage may release transmembrane collagens from the plasma membrane and affect extracellular matrix assembly or structure. However, the functional consequences of such cleavage are unclear and evidence for the role of specific PCSKs is lacking. Here, we used endogenous collagen fusions to fluorescent proteins to visualize the secretion and assembly of the first collagen-based cuticle in C. elegans and then tested the role of the PCSK BLI-4 in these processes. Unexpectedly, we found that cuticle collagens SQT-3 and DPY-17 are secreted into the extraembryonic space several hours before cuticle matrix assembly. Furthermore, this early secretion depends on BLI-4/PCSK; in bli-4 and cleavage-site mutants, SQT-3 and DPY-17 are not efficiently secreted and instead form large intracellular puncta. Their later assembly into cuticle matrix is reduced but not entirely blocked. These data reveal a role for collagen N-terminal processing in intracellular trafficking and the control of matrix assembly in vivo. Our observations also prompt a revision of the classic model for C. elegans cuticle matrix assembly and the pre-cuticle-to-cuticle transition, suggesting that cuticle layer assembly proceeds via a series of regulated steps and not simply by sequential secretion and deposition.
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Affiliation(s)
- Susanna K. Birnbaum
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Jennifer D. Cohen
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Alexandra Belfi
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - John I. Murray
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Jennifer R. G. Adams
- Departments of Neurobiology and Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Andrew D. Chisholm
- Departments of Neurobiology and Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Meera V. Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
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Birnbaum SK, Cohen JD, Belfi A, Murray JI, Adams JRG, Chisholm AD, Sundaram MV. The proprotein convertase BLI-4 promotes collagen secretion during assembly of the Caenorhabditis elegans cuticle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.542650. [PMID: 37333289 PMCID: PMC10274747 DOI: 10.1101/2023.06.06.542650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Some types of collagens, including transmembrane MACIT collagens and C. elegans cuticle collagens, are N-terminally cleaved at a dibasic site that resembles the consensus for furin or other proprotein convertases of the subtilisin/kexin (PCSK) family. Such cleavage may release transmembrane collagens from the plasma membrane and affect extracellular matrix assembly or structure. However, the functional consequences of such cleavage are unclear and evidence for the role of specific PCSKs is lacking. Here, we used endogenous collagen fusions to fluorescent proteins to visualize the secretion and assembly of the first collagen-based cuticle in C. elegans and then tested the role of the PCSK BLI-4 in these processes. Unexpectedly, we found that cuticle collagens SQT-3 and DPY-17 are secreted into the extraembryonic space several hours before cuticle matrix assembly. Furthermore, this early secretion depends on BLI-4/PCSK; in bli-4 and cleavage-site mutants, SQT-3 and DPY-17 are not efficiently secreted and instead form large intracellular aggregates. Their later assembly into cuticle matrix is reduced but not entirely blocked. These data reveal a role for collagen N-terminal processing in intracellular trafficking and in the spatial and temporal restriction of matrix assembly in vivo . Our observations also prompt a revision of the classic model for C. elegans cuticle matrix assembly and the pre-cuticle-to-cuticle transition, suggesting that cuticle layer assembly proceeds via a series of regulated steps and not simply by sequential secretion and deposition.
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Affiliation(s)
- Susanna K Birnbaum
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia PA
| | - Jennifer D Cohen
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia PA
| | - Alexandra Belfi
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia PA
| | - John I Murray
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia PA
| | - Jennifer R G Adams
- Departments of Neurobiology and Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego CA
| | - Andrew D Chisholm
- Departments of Neurobiology and Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego CA
| | - Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia PA
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Johnson LC, Vo AA, Clancy JC, Myles KM, Pooranachithra M, Aguilera J, Levenson MT, Wohlenberg C, Rechtsteiner A, Ragle JM, Chisholm AD, Ward JD. NHR-23 activity is necessary for C. elegans developmental progression and apical extracellular matrix structure and function. Development 2023; 150:dev201085. [PMID: 37129010 PMCID: PMC10233720 DOI: 10.1242/dev.201085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Nematode molting is a remarkable process where animals must repeatedly build a new apical extracellular matrix (aECM) beneath a previously built aECM that is subsequently shed. The nuclear hormone receptor NHR-23 (also known as NR1F1) is an important regulator of C. elegans molting. NHR-23 expression oscillates in the epidermal epithelium, and soma-specific NHR-23 depletion causes severe developmental delay and death. Tissue-specific RNAi suggests that nhr-23 acts primarily in seam and hypodermal cells. NHR-23 coordinates the expression of factors involved in molting, lipid transport/metabolism and remodeling of the aECM. NHR-23 depletion causes dampened expression of a nas-37 promoter reporter and a loss of reporter oscillation. The cuticle collagen ROL-6 and zona pellucida protein NOAH-1 display aberrant annular localization and severe disorganization over the seam cells after NHR-23 depletion, while the expression of the adult-specific cuticle collagen BLI-1 is diminished and frequently found in patches. Consistent with these localization defects, the cuticle barrier is severely compromised when NHR-23 is depleted. Together, this work provides insight into how NHR-23 acts in the seam and hypodermal cells to coordinate aECM regeneration during development.
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Affiliation(s)
- Londen C. Johnson
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - An A. Vo
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - John C. Clancy
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Krista M. Myles
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Murugesan Pooranachithra
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Joseph Aguilera
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Max T. Levenson
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Chloe Wohlenberg
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Andreas Rechtsteiner
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - James Matthew Ragle
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Andrew D. Chisholm
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jordan D. Ward
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
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