Publications by authors named "Suhong Xu"

23 Publications

  • Page 1 of 1

Redox-sensitive CDC-42 clustering promotes wound closure in C. elegans.

Cell Rep 2021 Nov;37(8):110040

Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China; Zhejiang University-University of Edinburgh Institute, Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China. Electronic address:

Tissue damage induces immediate-early signals, activating Rho small GTPases to trigger actin polymerization essential for later wound repair. However, how tissue damage is sensed to activate Rho small GTPases locally remains elusive. Here, we found that wounding the C. elegans epidermis induces rapid relocalization of CDC-42 into plasma membrane-associated clusters, which subsequently recruits WASP/WSP-1 to trigger actin polymerization to close the wound. In addition, wounding induces a local transient increase and subsequent reduction of HO, which negatively regulates the clustering of CDC-42 and wound closure. CDC-42 CAAX motif-mediated prenylation and polybasic region-mediated cation-phospholipid interaction are both required for its clustering. Cysteine residues participate in intermolecular disulfide bonds to reduce membrane association and are required for negative regulation of CDC-42 clustering by HO. Collectively, our findings suggest that HO-regulated fine-tuning of CDC-42 localization can create a distinct biomolecular cluster that facilitates rapid epithelial wound repair after injury.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2021.110040DOI Listing
November 2021

Caenorhabditis elegans Junctophilin has tissue-specific functions and regulates neurotransmission with extended-synaptotagmin.

Genetics 2021 Apr 19. Epub 2021 Apr 19.

Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA.

The junctophilin family of proteins tether together plasma membrane (PM) and endoplasmic reticulum (ER) membranes, and couple PM- and ER-localized calcium channels. Understanding in vivo functions of junctophilins is of great interest for dissecting the physiological roles of ER-PM contact sites. Here, we show that the sole C. elegans junctophilin JPH-1 localizes to discrete membrane contact sites in neurons and muscles and has important tissue-specific functions. jph-1 null mutants display slow growth and development due to weaker contraction of pharyngeal muscles, leading to reduced feeding. In the body wall muscle, JPH-1 co-localizes with the PM-localized EGL-19 voltage-gated calcium channel and ER-localized UNC-68/RyR calcium channel, and is required for animal movement. In neurons, JPH-1 co-localizes with the membrane contact site protein Extended-SYnaptoTagmin 2 (ESYT-2) in soma, and is present near presynaptic release sites. Interestingly, jph-1 and esyt-2 null mutants display mutual suppression in their response to aldicarb, suggesting that JPH-1 and ESYT-2 have antagonistic roles in neuromuscular synaptic transmission. Additionally, we find an unexpected cell non-autonomous effect of jph-1 in axon regrowth after injury. Genetic double mutant analysis suggests that jph-1 functions in overlapping pathways with two PM-localized voltage-gated calcium channels, egl-19 and unc-2, and unc-68/RyR for animal health and development. Finally, we show that jph-1 regulates the colocalization of EGL-19 and UNC-68 and that unc-68/RyR is required for JPH-1 localization to ER-PM puncta. Our data demonstrate important roles for junctophilin in cellular physiology, and also provide insights into how junctophilin functions together with other calcium channels in vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/genetics/iyab063DOI Listing
April 2021

Tracing cell-type evolution by cross-species comparison of cell atlases.

Cell Rep 2021 03;34(9):108803

Center for Stem Cell and Regenerative Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China; Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou 311121, China; Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Hangzhou 310058, China; Institute of Hematology, Zhejiang University, Hangzhou 310058, China; Stem Cell Institute, Zhejiang University, Hangzhou 310058, China. Electronic address:

Cell types are the basic building units of multicellular life, with extensive diversities. The evolution of cell types is a crucial layer of comparative cell biology but is thus far not comprehensively studied. We define a compendium of cell atlases using single-cell RNA-seq (scRNA-seq) data from seven animal species and construct a cross-species cell-type evolutionary hierarchy. We present a roadmap for the origin and diversity of major cell categories and find that muscle and neuron cells are conserved cell types. Furthermore, we identify a cross-species transcription factor (TF) repertoire that specifies major cell categories. Overall, our study reveals conservation and divergence of cell types during animal evolution, which will further expand the landscape of comparative genomics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2021.108803DOI Listing
March 2021

Caenorhabditis elegans homologue of Fam210 is required for oogenesis and reproduction.

J Genet Genomics 2020 11 5;47(11):694-704. Epub 2020 Dec 5.

MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address:

Mitochondria are the central hub for many metabolic processes, including the citric acid cycle, oxidative phosphorylation, and fatty acid oxidation. Recent studies have identified a new mitochondrial protein family, Fam210, that regulates bone metabolism and red cell development in vertebrates. The model organism Caenorhabditis elegans has a Fam210 gene, y56a3a.22, but it lacks both bones and red blood cells. In this study, we report that Y56A3A.22 plays a crucial role in regulating mitochondrial protein homeostasis and reproduction. The nematode y56a3a.22 is expressed in various tissues, including the intestine, muscle, hypodermis, and germline, and its encoded protein is predominantly localized in mitochondria. y56a3a.22 deletion mutants are sterile owing to impaired oogenesis. Loss of Y56A3A.22 induced mitochondrial unfolded protein response (UPR), which is mediated through the ATFS-1-dependent pathway, in tissues such as the intestine, germline, hypodermis, and vulval muscle. We further show that infertility and UPR induces by Y56A3A.22 deficiency are not attributed to systemic iron deficiency. Together, our study reveals an important role of Y56A3A.22 in regulating mitochondrial protein homeostasis and oogenesis and provides a new genetic tool for exploring the mechanisms regulating mitochondrial metabolism and reproduction as well as the fundamental role of the Fam210 family.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jgg.2020.10.008DOI Listing
November 2020

From wound response to repair - lessons from C. elegans.

Cell Regen 2021 Feb 3;10(1). Epub 2021 Feb 3.

The Zhejiang University-University of Edinburgh Institute and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.

As a result of evolution, the ability to repair wounds allows organisms to combat environment insults. Although the general process of wound healing at the tissue level has been described for decades, the detailed molecular mechanisms regarding the early wound response and rapid wound repair at the cellular level remain little understood. Caenorhabditis elegans is a model organism widely used in the field of development, neuroscience, programmed cell death etc. The nematode skin is composed of a large epidermis associated with a transparent extracellular cuticle, which likely has a robust capacity for epidermal repair. Yet, until the last decades, relatively few studies had directly analyzed the wound response and repair process. Here we review recent findings in how C. elegans epidermis responds to wounding and initiates early actin-polymerization-based wound closure as well as later membrane repair. We also discussed some remained outstanding questions for future study.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13619-020-00067-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7855202PMC
February 2021

Rapid and efficient wounding for in vivo studies of neuronal dendrite regeneration and degeneration.

J Genet Genomics 2021 02 7;48(2):163-166. Epub 2020 Nov 7.

Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058 China. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jgg.2020.10.003DOI Listing
February 2021

Protocol to Induce Wounding and Measure Membrane Repair in Epidermis.

STAR Protoc 2020 Dec 21;1(3):100175. Epub 2020 Nov 21.

Center for Stem Cell and Regenerative Medicine and Department of Cardiology of The Second Affiliated Hospital, Zhejiang University School of Medicine, 310058 Hangzhou, China.

Efficient membrane repair after injury is essential for cell and animal survival. epidermal cell hpy7 has emerged as a powerful genetic system to investigate the molecular mechanism of membrane repair . This protocol describes detailed approaches for how to perform wounding on the epidermis and how to examine membrane repair by trypan blue staining, confocal imaging, and data analysis. For details on the use and execution of this protocol, please refer to Meng et al. (2020).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.xpro.2020.100175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757402PMC
December 2020

Sensory Glia Detect Repulsive Odorants and Drive Olfactory Adaptation.

Neuron 2020 11 23;108(4):707-721.e8. Epub 2020 Sep 23.

Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang 310053, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China. Electronic address:

Glia are typically considered as supporting cells for neural development and synaptic transmission. Here, we report an active role of a glia in olfactory transduction. As a polymodal sensory neuron in C. elegans, the ASH neuron is previously known to detect multiple aversive odorants. We reveal that the AMsh glia, a sheath for multiple sensory neurons including ASH, cell-autonomously respond to aversive odorants via G-protein-coupled receptors (GPCRs) distinct from those in ASH. Upon activation, the AMsh glia suppress aversive odorant-triggered avoidance and promote olfactory adaptation by inhibiting the ASH neuron via GABA signaling. Thus, we propose a novel two-receptor model where the glia and sensory neuron jointly mediate adaptive olfaction. Our study reveals a non-canonical function of glial cells in olfactory transduction, which may provide new insights into the glia-like supporting cells in mammalian sensory procession.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuron.2020.08.026DOI Listing
November 2020

Actin Polymerization and ESCRT Trigger Recruitment of the Fusogens Syntaxin-2 and EFF-1 to Promote Membrane Repair in C. elegans.

Dev Cell 2020 09 14;54(5):624-638.e5. Epub 2020 Jul 14.

Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China; The Zhejiang University, University of Edinburgh Institute, 718 East Haizhou Road, Haining, Zhejiang 314400, China. Electronic address:

Membrane repair is essential for cell and organism survival. Exocytosis and endocytosis facilitate membrane repair in small wounds within a single cell; however, it remains unclear how large wounds in the plasma membrane are repaired in metazoans. Here, we show that wounding triggers rapid transcriptional upregulation and dynamic recruitment of the fusogen EFF-1 to the wound site in C. elegans epidermal cells. EFF-1 recruitment at the wounded membrane depends on the actin cytoskeleton and is important for membrane repair. We identified syntaxin-2 (SYX-2) as an essential regulator of EFF-1 recruitment. SYX-2 interacts with the C terminus of EFF-1 to promote its recruitment, facilitating both endoplasmic and exoplasmic membrane repair. Furthermore, we show that SYX-2-EFF-1 repair machinery acts downstream of the ESCRT III signal. Together, our findings identify a key pathway underlying membrane repair and provide insights into tissue repair and regenerative medicine after injury.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.devcel.2020.06.027DOI Listing
September 2020

Wounding triggers MIRO-1 dependent mitochondrial fragmentation that accelerates epidermal wound closure through oxidative signaling.

Nat Commun 2020 02 26;11(1):1050. Epub 2020 Feb 26.

Center for Stem Cell and Regenerative Medicine and Department of Cardiology of The Second Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China.

Organisms respond to tissue damage through the upregulation of protective responses which restore tissue structure and metabolic function. Mitochondria are key sources of intracellular oxidative metabolic signals that maintain cellular homeostasis. Here we report that tissue and cellular wounding triggers rapid and reversible mitochondrial fragmentation. Elevated mitochondrial fragmentation either in fzo-1 fusion-defective mutants or after acute drug treatment accelerates actin-based wound closure. Wounding triggered mitochondrial fragmentation is independent of the GTPase DRP-1 but acts via the mitochondrial Rho GTPase MIRO-1 and cytosolic Ca. The fragmented mitochondria and accelerated wound closure of fzo-1 mutants are dependent on MIRO-1 function. Genetic and transcriptomic analyzes show that enhanced mitochondrial fragmentation accelerates wound closure via the upregulation of mtROS and Cytochrome P450. Our results reveal how mitochondrial dynamics respond to cellular and tissue injury and promote tissue repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-020-14885-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7044169PMC
February 2020

The mRNA Decay Factor CAR-1/LSM14 Regulates Axon Regeneration via Mitochondrial Calcium Dynamics.

Curr Biol 2020 03 23;30(5):865-876.e7. Epub 2020 Jan 23.

Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA. Electronic address:

mRNA decay factors regulate mRNA turnover by recruiting non-translating mRNAs and targeting them for translational repression and mRNA degradation. How mRNA decay pathways regulate cellular function in vivo with specificity is poorly understood. Here, we show that C. elegans mRNA decay factors, including the translational repressors CAR-1/LSM14 and CGH-1/DDX6, and the decapping enzymes DCAP-1/DCP1, function in neurons to differentially regulate axon development, maintenance, and regrowth following injury. In neuronal cell bodies, CAR-1 fully colocalizes with CGH-1 and partially colocalizes with DCAP-1, suggesting that mRNA decay components form at least two types of cytoplasmic granules. Following axon injury in adult neurons, loss of CAR-1 or CGH-1 results in increased axon regrowth and growth cone formation, whereas loss of DCAP-1 or DCAP-2 results in reduced regrowth. To determine how CAR-1 inhibits regrowth, we analyzed mRNAs bound to pan-neuronally expressed GFP::CAR-1 using a crosslinking and immunoprecipitation-based approach. Among the putative mRNA targets of CAR-1, we characterized the roles of micu-1, a regulator of the mitochondrial calcium uniporter MCU-1, in axon injury. We show that loss of car-1 results increased MICU-1 protein levels, and that enhanced axon regrowth in car-1 mutants is dependent on micu-1 and mcu-1. Moreover, axon injury induces transient calcium influx into axonal mitochondria, dependent on MCU-1. In car-1 loss-of-function mutants and in micu-1 overexpressing animals, the axonal mitochondrial calcium influx is more sustained, which likely underlies enhanced axon regrowth. Our data uncover a novel pathway that controls axon regrowth through axonal mitochondrial calcium uptake.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2019.12.061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7147385PMC
March 2020

[CRISPR-Cas9 mediated genome editing in Caenorhabditis elegans].

Sheng Wu Gong Cheng Xue Bao 2017 Oct;33(10):1693-1699

School of Medicine, Zhejiang University, Hangzhou 310058, Zhejiang, China.

The development of genome editing techniques based on CRISPR (Clustered regularly interspaced short palindromic repeats)-Cas9 system has revolutionized biomedical researches. It can be utilized to edit genome sequence in almost any organisms including Caenorhabditis elegans, one of the most convenient and classic genetic model animals. The application of CRISPR-Cas9 mediated genome editing in C. elegans promotes the functional analysis of gene and proteins under many physiological conditions. In this mini-review, we summarized the development of CRISPR-Cas9-based genome editing in C. elegans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.13345/j.cjb.170177DOI Listing
October 2017

DAPK interacts with Patronin and the microtubule cytoskeleton in epidermal development and wound repair.

Elife 2016 09 23;5. Epub 2016 Sep 23.

Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, San Diego, United States.

Epidermal barrier epithelia form a first line of defense against the environment, protecting animals against infection and repairing physical damage. In death-associated protein kinase (DAPK-1) regulates epidermal morphogenesis, innate immunity and wound repair. Combining genetic suppressor screens and pharmacological tests, we find that DAPK-1 maintains epidermal tissue integrity through regulation of the microtubule (MT) cytoskeleton. epidermal phenotypes are suppressed by treatment with microtubule-destabilizing drugs and mimicked or enhanced by microtubule-stabilizing drugs. Loss of function in , the member of the Patronin/Nezha/CAMSAP family of MT minus-end binding proteins, suppresses epidermal and innate immunity phenotypes. Over-expression of the MT-binding CKK domain of PTRN-1 triggers epidermal and immunity defects resembling those of mutants, and PTRN-1 localization is regulated by DAPK-1. DAPK-1 and PTRN-1 physically interact in co-immunoprecipitation experiments, and DAPK-1 itself undergoes MT-dependent transport. Our results uncover an unexpected interdependence of DAPK-1 and the microtubule cytoskeleton in maintenance of epidermal integrity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053806PMC
http://dx.doi.org/10.7554/eLife.15833DOI Listing
September 2016

Targeted Mutagenesis of Duplicated Genes in Caenorhabditis elegans Using CRISPR-Cas9.

J Genet Genomics 2016 Feb 25;43(2):103-6. Epub 2016 Jan 25.

Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jgg.2015.11.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5291165PMC
February 2016

Highly efficient optogenetic cell ablation in C. elegans using membrane-targeted miniSOG.

Sci Rep 2016 Feb 10;6:21271. Epub 2016 Feb 10.

Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093.

The genetically encoded photosensitizer miniSOG (mini Singlet Oxygen Generator) can be used to kill cells in C. elegans. miniSOG generates the reactive oxygen species (ROS) singlet oxygen after illumination with blue light. Illumination of neurons expressing miniSOG targeted to the outer mitochondrial membrane (mito-miniSOG) causes neuronal death. To enhance miniSOG's efficiency as an ablation tool in multiple cell types we tested alternative targeting signals. We find that membrane targeted miniSOG allows highly efficient cell killing. When combined with a point mutation that increases miniSOG's ROS generation, membrane targeted miniSOG can ablate neurons in less than one tenth the time of mito-miniSOG. We extend the miniSOG ablation technique to non-neuronal tissues, revealing an essential role for the epidermis in locomotion. These improvements expand the utility and throughput of optogenetic cell ablation in C. elegans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep21271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748272PMC
February 2016

The application of CRISPR-Cas9 genome editing in Caenorhabditis elegans.

Authors:
Suhong Xu

J Genet Genomics 2015 Aug 26;42(8):413-21. Epub 2015 Jun 26.

Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. Electronic address:

Genome editing using the Cas9 endonuclease of Streptococcus pyogenes has demonstrated unparalleled efficacy and facility for modifying genomes in a wide variety of organisms. Caenorhabditis elegans is one of the most convenient multicellular organisms for genetic analysis, and the application of this novel genome editing technique to this organism promises to revolutionize analysis of gene function in the future. CRISPR-Cas9 has been successfully used to generate imprecise insertions and deletions via non-homologous end-joining mechanisms and to create precise mutations by homology-directed repair from donor templates. Key variables are the methods used to deliver the Cas9 endonuclease and the efficiency of the single guide RNAs. CRISPR-Cas9-mediated editing appears to be highly specific in C. elegans, with no reported off-target effects. In this review, I briefly summarize recent progress in CRISPR-Cas9-based genome editing in C. elegans, highlighting technical improvements in mutagenesis and mutation detection, and discuss potential future applications of this technique.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jgg.2015.06.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4560834PMC
August 2015

Methods for skin wounding and assays for wound responses in C. elegans.

J Vis Exp 2014 Dec 3(94). Epub 2014 Dec 3.

Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego;

The C. elegans epidermis and cuticle form a simple yet sophisticated skin layer that can repair localized damage resulting from wounding. Studies of wound responses and repair in this model have illuminated our understanding of the cytoskeletal and genomic responses to tissue damage. The two most commonly used methods to wound the C. elegans adult skin are pricks with microinjection needles, and local laser irradiation. Needle wounding locally disrupts the cuticle, epidermis, and associated extracellular matrix, and may also damage internal tissues. Laser irradiation results in more localized damage. Wounding triggers a succession of readily assayed responses including elevated epidermal Ca(2+) (seconds-minutes), formation and closure of an actin-containing ring at the wound site (1-2 hr), elevated transcription of antimicrobial peptide genes (2-24 hr), and scar formation. Essentially all wild type adult animals survive wounding, whereas mutants defective in wound repair or other responses show decreased survival. Detailed protocols for needle and laser wounding, and assays for quantitation and visualization of wound responses and repair processes (Ca dynamics, actin dynamics, antimicrobial peptide induction, and survival) are presented.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3791/51959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4396949PMC
December 2014

C. elegans epidermal wounding induces a mitochondrial ROS burst that promotes wound repair.

Dev Cell 2014 Oct;31(1):48-60

Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. Electronic address:

Reactive oxygen species (ROS) such as hydrogen peroxide are generated at wound sites and act as long-range signals in wound healing. The roles of other ROS in wound repair are little explored. Here, we reveal a cytoprotective role for mitochondrial ROS (mtROS) in Caenorhabditis elegans skin wound healing. We show that skin wounding causes local production of mtROS superoxide at the wound site. Inhibition of mtROS levels by mitochondrial superoxide-specific antioxidants blocks actin-based wound closure, whereas elevation of mtROS promotes wound closure and enhances survival of mutant animals defective in wound healing. mtROS act downstream of wound-triggered Ca(2+) influx. We find that the mitochondrial calcium uniporter MCU-1 is essential for rapid mitochondrial Ca(2+) uptake and mtROS production after wounding. mtROS can promote wound closure by local inhibition of Rho GTPase activity via a redox-sensitive motif. These findings delineate a pathway acting via mtROS that promotes cytoskeletal responses in wound healing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.devcel.2014.08.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4197410PMC
October 2014

The Caenorhabditis elegans epidermis as a model skin. II: differentiation and physiological roles.

Wiley Interdiscip Rev Dev Biol 2012 Nov-Dec;1(6):879-902. Epub 2012 Jun 19.

Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/wdev.77DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3607645PMC
January 2014

MiniSOG-mediated Photoablation in .

Bio Protoc 2013 Jan;3(1)

Division of Biological Sciences, Neurobiology Section, University of California, San Diego, CA, USA.

This protocol describes a method for light-inducible cell ablation in live worms. miniSOG (mini Singlet Oxygen Generator) generates singlet oxygen upon blue light illumination (Shu 2011). Mitochondrially membrane targeted miniSOG (the first 55 a. a. of tomm-20 fused at the N'-terminus of miniSOG, termed as mito-miniSOG in the following) is transgenically expressed in specific cells/tissues (Qi ., 2012). Groups of transgenic animals are illuminated under open field fluorescence light on a compound microscope or LED light setup for photo-ablation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982655PMC
http://dx.doi.org/10.21769/bioprotoc.316DOI Listing
January 2013

The wounded worm: Using C. elegans to understand the molecular basis of skin wound healing.

Worm 2012 Apr;1(2):134-8

Division of Biological Sciences; Section of Cell and Developmental Biology; University of California San Diego; La Jolla, CA USA.

The ability to heal wounds is an ancient and conserved function of epidermal epithelial layers. The importance of skin wound healing to human life and biology has long been evident, however many of the molecular mechanisms underlying wound repair remain little understood. In the past several years, analysis of the C. elegans innate immune response to fungal infection of the epidermis has led to investigations of the ability of the C. elegans skin to respond to damage. In a recent paper we used live imaging to investigate the cell biological basis of wound repair in the adult C. elegans epidermis. We found that needle or laser injury of the skin triggers a large and sustained increase in epidermal calcium. Epidermal calcium signals appear to specifically promote actin-dependent processes of wound closure. The innate immune and wound closure responses act in parallel to promote survival after injury. Our findings indicate that wounding triggers multiple signals in the C. elegans skin. C. elegans offers a tractable model to dissect how epidermal epithelia activate coordinated responses to repair damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4161/worm.19501DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3670230PMC
April 2012

Maternal xNorrin, a canonical Wnt signaling agonist and TGF-β antagonist, controls early neuroectoderm specification in Xenopus.

PLoS Biol 2012 20;10(3):e1001286. Epub 2012 Mar 20.

State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.

Dorsal-ventral specification in the amphibian embryo is controlled by β-catenin, whose activation in all dorsal cells is dependent on maternal Wnt11. However, it remains unknown whether other maternally secreted factors contribute to β-catenin activation in the dorsal ectoderm. Here, we show that maternal Xenopus Norrin (xNorrin) promotes anterior neural tissue formation in ventralized embryos. Conversely, when xNorrin function is inhibited, early canonical Wnt signaling in the dorsal ectoderm and the early expression of the zygotic neural inducers Chordin, Noggin, and Xnr3 are severely suppressed, causing the loss of anterior structures. In addition, xNorrin potently inhibits BMP- and Nodal/Activin-related functions through direct binding to the ligands. Moreover, a subset of Norrin mutants identified in humans with Norrie disease retain Wnt activation but show defective inhibition of Nodal/Activin-related signaling in mesoderm induction, suggesting that this disinhibition causes Norrie disease. Thus, xNorrin is an unusual molecule that acts on two major signaling pathways, Wnt and TGF-β, in opposite ways and is essential for early neuroectoderm specification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pbio.1001286DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308935PMC
July 2012

A Gαq-Ca²⁺ signaling pathway promotes actin-mediated epidermal wound closure in C. elegans.

Curr Biol 2011 Dec 17;21(23):1960-7. Epub 2011 Nov 17.

Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.

Background: Repair of skin wounds is essential for animals to survive in a harsh environment, yet the signaling pathways initiating wound repair in vivo remain little understood. In Caenorhabditis elegans, a p38 mitogen-activated protein kinase (MAPK) cascade promotes innate immune responses to wounding but is not required for other aspects of wound healing. We therefore set out to identify additional wound response pathways in C. elegans epidermis.

Results: We show here that wounding the adult C. elegans skin triggers a rapid and sustained rise in epidermal Ca(2+) that is critical for survival after wounding. The wound-triggered rise in Ca(2+) requires the epidermal transient receptor potential channel, melastatin family (TRPM) channel GTL-2 and IP(3)R-stimulated release from internal stores. We identify an epidermal signal transduction pathway that includes the Gα(q) EGL-30 and its effector PLCβ EGL-8. Loss of function in this pathway impairs survival after wounding. The Gα(q)-Ca(2+) pathway is not required for known innate immune responses to wounding but instead promotes actin-dependent wound closure. Wound closure requires the Cdc42 small GTPase and Arp2/3-dependent actin polymerization and is negatively regulated by Rho and nonmuscle myosin. Finally, we show that the death-associated protein kinase DAPK-1 acts as a negative regulator of wound closure.

Conclusions: Skin wounding in C. elegans triggers a Ca(2+)-dependent signaling cascade that promotes wound closure, in parallel to the innate immune response to damage. Wound closure requires actin polymerization and is negatively regulated by nonmuscle myosin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2011.10.050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3237753PMC
December 2011
-->