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A Caenorhabditis elegans nck-1 and filamentous actin-regulating protein pathway mediates a key cellular defense against bacterial pore-forming proteins. PLoS Pathog 2022; 18:e1010656. [PMID: 36374839 PMCID: PMC9704757 DOI: 10.1371/journal.ppat.1010656] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 11/28/2022] [Accepted: 10/27/2022] [Indexed: 11/15/2022] Open
Abstract
Pore-forming proteins (PFPs) comprise the largest single class of bacterial protein virulence factors and are expressed by many human and animal bacterial pathogens. Cells that are attacked by these virulence factors activate epithelial intrinsic cellular defenses (or INCEDs) to prevent the attendant cellular damage, cellular dysfunction, osmotic lysis, and organismal death. Several conserved PFP INCEDs have been identified using the nematode Caenorhabditis elegans and the nematicidal PFP Cry5B, including mitogen-activated protein kinase (MAPK) signaling pathways. Here we demonstrate that the gene nck-1, which has homologs from Drosophila to humans and links cell signaling with localized F-actin polymerization, is required for INCED against small-pore PFPs in C. elegans. Reduction/loss of nck-1 function results in C. elegans hypersensitivity to PFP attack, a hallmark of a gene required for INCEDs against PFPs. This requirement for nck-1-mediated INCED functions cell-autonomously in the intestine and is specific to PFPs but not to other tested stresses. Genetic interaction experiments indicate that nck-1-mediated INCED against PFP attack is independent of the major MAPK PFP INCED pathways. Proteomics and cell biological and genetic studies further indicate that nck-1 functions with F-actin cytoskeleton modifying genes like arp2/3, erm-1, and dbn-1 and that nck-1/arp2/3 promote pore repair at the membrane surface and protect against PFP attack independent of p38 MAPK. Consistent with these findings, PFP attack causes significant changes in the amount of actin cytoskeletal proteins and in total amounts of F-actin in the target tissue, the intestine. nck-1 mutant animals appear to have lower F-actin levels than wild-type C. elegans. Studies on nck-1 and other F-actin regulating proteins have uncovered a new and important role of this pathway and the actin cytoskeleton in PFP INCED and protecting an intestinal epithelium in vivo against PFP attack.
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Bhatia S, Hunter CP. SID-4/NCK-1 is important for dsRNA import in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2022; 12:6722623. [PMID: 36165710 PMCID: PMC9635667 DOI: 10.1093/g3journal/jkac252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 08/25/2022] [Indexed: 12/24/2022]
Abstract
RNA interference is sequence-specific gene silencing triggered by double-stranded RNA. Systemic RNA interference is where double-stranded RNA, expressed or introduced into 1 cell, is transported to and initiates RNA interference in other cells. Systemic RNA interference is very efficient in Caenorhabditis elegans and genetic screens for systemic RNA interference-defective mutants have identified RNA transporters (SID-1, SID-2, and SID-5) and a signaling protein (SID-3). Here, we report that SID-4 is nck-1, a C. elegans NCK-like adaptor protein. sid-4 null mutations cause a weak, dose-sensitive, systemic RNA interference defect and can be effectively rescued by SID-4 expression in target tissues only, implying a role in double-stranded RNA import. SID-4 and SID-3 (ACK-1 kinase) homologs interact in mammals and insects, suggesting that they may function in a common signaling pathway; however, a sid-3; sid-4 double mutants showed additive resistance to RNA interference, suggesting that these proteins likely interact with other signaling pathways as well. A bioinformatic screen coupled to RNA interference sensitivity tests identified 23 additional signaling components with weak RNA interference-defective phenotypes. These observations suggest that environmental conditions may modulate systemic RNA interference efficacy, and indeed, sid-3 and sid-4 are required for growth temperature effects on systemic RNA interference silencing efficiency.
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Affiliation(s)
- Sonya Bhatia
- Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138, USA
| | - Craig P Hunter
- Corresponding author: Department of Molecular and Cellular Biology, 16 Divinity Avenue, Harvard University, Cambridge MA, 02138 USA.
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Rikitake M, Matsuda A, Murata D, Dejima K, Nomura KH, Abbott KL, Mitani S, Nomura K. Analysis of GPI-anchored proteins involved in germline stem cell proliferation in the Caenorhabditis elegans germline stem cell niche. J Biochem 2020; 168:589-602. [PMID: 32844210 DOI: 10.1093/jb/mvaa075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/24/2020] [Indexed: 11/14/2022] Open
Abstract
Stem cells divide and undergo self-renewal depending on the signals received from the stem cell niche. This phenomenon is indispensable to maintain tissues and organs in individuals. However, not all the molecular factors and mechanisms of self-renewal are known. In our previous study, we reported that glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) synthesized in the distal tip cells (DTCs; the stem cell niche) are essential for germline stem cell proliferation in Caenorhabditis elegans. Here, we characterized the GPI-APs required for proliferation. We selected and verified the candidate GPI-APs synthesized in DTCs by RNA interference screening and found that F57F4.3 (GFI-1), F57F4.4 and F54E2.1 are necessary for germline proliferation. These proteins are likely involved in the same pathway for proliferation and activated by the transcription factor PQM-1. We further provided evidence suggesting that these GPI-APs act through fatty acid remodelling of the GPI anchor, which is essential for association with lipid rafts. These findings demonstrated that GPI-APs, particularly F57F4.3/4 and F54E2.1, synthesized in the germline stem cell niche are located in lipid rafts and involved in promoting germline stem cell proliferation in C. elegans. The findings may thus shed light on the mechanisms by which GPI-APs regulate stem cell self-renewal.
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Affiliation(s)
- Marika Rikitake
- Department of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 819-0395, Japan
| | - Ayako Matsuda
- Department of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 819-0395, Japan
| | - Daisuke Murata
- Department of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 819-0395, Japan.,CREST (JST), Saitama 332-0012, Japan.,Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, 113 Hunterian, Baltimore, MD 21205, USA
| | - Katsufumi Dejima
- CREST (JST), Saitama 332-0012, Japan.,Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo 162-8666, Japan
| | - Kazuko H Nomura
- CREST (JST), Saitama 332-0012, Japan.,Department of Biology, Kyushu University, Fukuoka 819-0395, Japan
| | - Karen L Abbott
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, 9 Stephenson Cancer Center, Oklahoma City, OK 73104, USA.,SL Young Biomedical Research Center, 975 NE 10th St., BRC 409 North lab/411A Office, Little Rock, AR 72205, USA
| | - Shohei Mitani
- CREST (JST), Saitama 332-0012, Japan.,Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo 162-8666, Japan
| | - Kazuya Nomura
- CREST (JST), Saitama 332-0012, Japan.,Department of Biology, Kyushu University, Fukuoka 819-0395, Japan.,Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
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Yin J, Liu R, Jian Z, Yang D, Pu Y, Yin L, Wang D. Di (2-ethylhexyl) phthalate-induced reproductive toxicity involved in dna damage-dependent oocyte apoptosis and oxidative stress in Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 163:298-306. [PMID: 30056344 DOI: 10.1016/j.ecoenv.2018.07.066] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 07/15/2018] [Accepted: 07/18/2018] [Indexed: 06/08/2023]
Abstract
Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer with a high environmental exposure level. As a persistent organic pollutant, DEHP causes reproductive and developmental toxicity in mammals. In this paper, the reproductive toxicity of DEHP was discussed using the model organism Caenorhabditis elegans to determine the sensitivity indices for evaluating the ecotoxicological effects of DEHP. L4 C. elegans larvae to evaluate the LC50 of DEHP and the changes in brood size and generation time, we found that the LC50 of DEHP to C. elegans exceeded 100 mg/L. And 10 mg/L DEHP exposure significantly reduced the brood sizes but not the generation time. Results of oocyte and distal-tip cell (DTC) counting suggested that the number of oocytes were decreased and apoptotic cells that from the unilateral gonad arm were increased in the 1 mg/L and 10 mg/L DEHP exposed groups. In contrast, there was no significant difference in the fluorescence intensity of DTC. Fluorescence analysis of HUS-1 showed that HUS-1 protein was overexpressed after DEHP exposure. The H2O2 level and DNA damage were measured by Bradford protein assay and AP staining respectively. The results showed that there was no significant difference in H2O2 level after DEHP exposure, in contrast, DNA damage was increased significantly. Moreover, 10 mg/L concentration DEHP exposure significantly increased the expression levels of apoptosis-related genes cep-1, egl-1, ced-4, and ced-3 and decreased the expression levels of ced-9. It suggested that cep-1, egl-1, ced-4, and ced-3 genes promote apoptosis and the ced-9 gene inhibits apoptosis. Meanwhile, 10 mg/L concentration DEHP exposure decreased the expression of oxidative stress-related genes mev-1 and gas-1. The mev-1 and gas-1 are mainly involved in the inhibition of oxidative stress in nematodes. In short, the decreased oocyte numbers and increased apoptosis oocyte numbers in C. elegans when exposed to DEHP, which may involve in the DNA damage induced by oxidative stress.
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Affiliation(s)
- Jiechen Yin
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Ran Liu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Zihai Jian
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Dong Yang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Yuepu Pu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Lihong Yin
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
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Abstract
Many stem cell niches contain support cells that increase contact with stem cells by enwrapping them in cellular processes. One example is the germ stem cell niche in C. elegans, which is composed of a single niche cell termed the distal tip cell (DTC) that extends cellular processes, constructing an elaborate plexus that enwraps germ stem cells. To identify genes required for plexus formation and to explore the function of this specialized enwrapping behavior, a series of targeted and tissue-specific RNAi screens were performed. Here we identify genes that promote stem cell enwrapment by the DTC plexus, including a set that specifically functions within the DTC, such as the chromatin modifier lin-40/MTA1, and others that act within the germline, such as the 14-3-3 signaling protein par-5. Analysis of genes that function within the germline to mediate plexus development reveal that they are required for expansion of the germ progenitor zone, supporting the emerging idea that germ stem cells signal to the niche to stimulate enwrapping behavior. Examination of wild-type animals with asymmetric plexus formation and animals with reduced DTC plexus elaboration via loss of two candidates including lin-40 indicate that cellular enwrapment promotes GLP-1/Notch signaling and germ stem cell fate. Together, our work identifies novel regulators of cellular enwrapment and suggests that reciprocal signaling between the DTC niche and the germ stem cells promotes enwrapment behavior and stem cell fate.
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Ishii T, Funato Y, Hashizume O, Yamazaki D, Hirata Y, Nishiwaki K, Kono N, Arai H, Miki H. Mg2+ Extrusion from Intestinal Epithelia by CNNM Proteins Is Essential for Gonadogenesis via AMPK-TORC1 Signaling in Caenorhabditis elegans. PLoS Genet 2016; 12:e1006276. [PMID: 27564576 PMCID: PMC5001713 DOI: 10.1371/journal.pgen.1006276] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 08/04/2016] [Indexed: 02/03/2023] Open
Abstract
Mg2+ serves as an essential cofactor for numerous enzymes and its levels are tightly regulated by various Mg2+ transporters. Here, we analyzed Caenorhabditis elegans strains carrying mutations in genes encoding cyclin M (CNNM) Mg2+ transporters. We isolated inactivating mutants for each of the five Caenorhabditis elegans cnnm family genes, cnnm-1 through cnnm-5. cnnm-1; cnnm-3 double mutant worms showed various phenotypes, among which the sterile phenotype was rescued by supplementing the media with Mg2+. This sterility was caused by a gonadogenesis defect with severely attenuated proliferation of germ cells. Using this gonadogenesis defect as an indicator, we performed genome-wide RNAi screening, to search for genes associated with this phenotype. The results revealed that RNAi-mediated inactivation of several genes restores gonad elongation, including aak-2, which encodes the catalytic subunit of AMP-activated protein kinase (AMPK). We then generated triple mutant worms for cnnm-1; cnnm-3; aak-2 and confirmed that the aak-2 mutation also suppressed the defective gonadal elongation in cnnm-1; cnnm-3 mutant worms. AMPK is activated under low-energy conditions and plays a central role in regulating cellular metabolism to adapt to the energy status of cells. Thus, we provide genetic evidence linking Mg2+ homeostasis to energy metabolism via AMPK. Mg2+ is the second most abundant cation in cells and serves as an essential cofactor for numerous enzymes. To avoid its shortage, cellular and organismal levels of Mg2+ are tightly regulated by the concerted actions of various Mg2+ transporters and channels. In this study, we analyzed Caenorhabditis elegans strains carrying mutations in genes encoding Mg2+ transporters and found that the mutations abrogated Mg2+ homeostasis. Additionally, these worms were sterile because of a developmental defect in the gonads with severely attenuated proliferation of germ cells. These abnormalities were rescued by additional Mg2+ supplementation to the medium, and thus were considered to be due to Mg2+ shortage. We investigated the mechanism of this Mg2+-associated attenuation of gonadal development, and found that disrupting of the function of AMP-activated protein kinase (AMPK) restored gonad elongation. It is well-known that AMPK is activated under low-energy conditions and plays a central role in regulating cellular metabolism to adapt to the energy status of cells. Thus, we demonstrated that Mg2+ homeostasis is intimately connected to energy metabolism via AMPK.
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Affiliation(s)
- Tasuku Ishii
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yosuke Funato
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- * E-mail: (YF); (HM)
| | - Osamu Hashizume
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Daisuke Yamazaki
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yusuke Hirata
- Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Kiyoji Nishiwaki
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, Japan
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- PRIME, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, Japan
| | - Hiroaki Miki
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- * E-mail: (YF); (HM)
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Wong MC, Kennedy WP, Schwarzbauer JE. Transcriptionally regulated cell adhesion network dictates distal tip cell directionality. Dev Dyn 2014; 243:999-1010. [PMID: 24811939 DOI: 10.1002/dvdy.24146] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The mechanisms that govern directional changes in cell migration are poorly understood. The migratory paths of two distal tip cells (DTC) determine the U-shape of the C. elegans hermaphroditic gonad. The morphogenesis of this organ provides a model system to identify genes necessary for the DTCs to execute two stereotyped turns. RESULTS Using candidate genes for RNAi knockdown in a DTC-specific strain, we identified two transcriptional regulators required for DTC turning: cbp-1, the CBP/p300 transcriptional coactivator homologue, and let-607, a CREBH transcription factor homologue. Further screening of potential target genes uncovered a network of integrin adhesion-related genes that have roles in turning and are dependent on cbp-1 and let-607 for expression. These genes include src-1/Src kinase, tln-1/talin, pat-2/α integrin and nmy-2, a nonmuscle myosin heavy chain. CONCLUSIONS Transcriptional regulation by means of cbp-1 and let-607 is crucial for determining directional changes during DTC migration. These regulators coordinate a gene network that is necessary for integrin-mediated adhesion. Overall, these results suggest that directional changes in cell migration rely on the precise gene regulation of adhesion.
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Affiliation(s)
- Ming-Ching Wong
- Department of Molecular Biology, Princeton University, Princeton, New Jersey
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Lewellyn L, Cetera M, Horne-Badovinac S. Misshapen decreases integrin levels to promote epithelial motility and planar polarity in Drosophila. ACTA ACUST UNITED AC 2013; 200:721-9. [PMID: 23509067 PMCID: PMC3601364 DOI: 10.1083/jcb.201209129] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Complex organ shapes arise from the coordinate actions of individual cells. The Drosophila egg chamber is an organ-like structure that lengthens along its anterior-posterior axis as it grows. This morphogenesis depends on an unusual form of planar polarity in the organ's outer epithelial layer, the follicle cells. Interestingly, this epithelium also undergoes a directed migration that causes the egg chamber to rotate around its anterior-posterior axis. However, the functional relationship between planar polarity and migration in this tissue is unknown. We have previously reported that mutations in the Misshapen kinase disrupt follicle cell planar polarity. Here we show that Misshapen's primary role in this system is to promote individual cell motility. Misshapen decreases integrin levels at the basal surface, which may facilitate detachment of each cell's trailing edge. These data provide mechanistic insight into Misshapen's conserved role in cell migration and suggest that follicle cell planar polarity may be an emergent property of individual cell migratory behaviors within the epithelium.
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Affiliation(s)
- Lindsay Lewellyn
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
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