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Salcedo-Tacuma D, Asad N, Howells G, Anderson R, Smith DM. Proteasome hyperactivation rewires the proteome enhancing stress resistance, proteostasis, lipid metabolism and ERAD in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588128. [PMID: 38617285 PMCID: PMC11014606 DOI: 10.1101/2024.04.04.588128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Proteasome dysfunction is implicated in the pathogenesis of neurodegenerative diseases and age-related proteinopathies. Using a C. elegans model, we demonstrate that 20S proteasome hyperactivation, facilitated by 20S gate-opening, accelerates the targeting of intrinsically disordered proteins. This leads to increased protein synthesis, extensive rewiring of the proteome and transcriptome, enhanced oxidative stress defense, accelerated lipid metabolism, and peroxisome proliferation. It also promotes ER-associated degradation (ERAD) of aggregation-prone proteins, such as alpha-1 antitrypsin (ATZ) and various lipoproteins. Notably, our results reveal that 20S proteasome hyperactivation suggests a novel role in ERAD with broad implications for proteostasis-related disorders, simultaneously affecting lipid homeostasis and peroxisome proliferation. Furthermore, the enhanced cellular capacity to mitigate proteostasis challenges, alongside unanticipated acceleration of lipid metabolism is expected to contribute to the longevity phenotype of this mutant. Remarkably, the mechanism of longevity induced by 20S gate opening appears unique, independent of known longevity and stress-resistance pathways. These results support the therapeutic potential of 20S proteasome activation in mitigating proteostasis-related disorders broadly and provide new insights into the complex interplay between proteasome activity, cellular health, and aging.
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Affiliation(s)
- David Salcedo-Tacuma
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Nadeeem. Asad
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Giovanni Howells
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Raymond Anderson
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - David M. Smith
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
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2
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Fanelli MJ, Welsh CM, Lui DS, Smulan LJ, Walker AK. Immunity-linked genes are stimulated by a membrane stress pathway linked to Golgi function and the ARF-1 GTPase. SCIENCE ADVANCES 2023; 9:eadi5545. [PMID: 38055815 PMCID: PMC10699786 DOI: 10.1126/sciadv.adi5545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
Infection response and other immunity-linked genes (ILGs) were first named in Caenorhabditis elegans-based expression after pathogen challenge, but many are also up-regulated when lipid metabolism is perturbed. Why pathogen attack and metabolic changes both increase ILGs is unclear. We find that ILGs are activated when phosphatidylcholine (PC) levels change in membranes of secretory organelles in C. elegans. RNAi targeting of the ADP-ribosylation factor arf-1, which disrupts the Golgi and secretory function, also activates ILGs. Low PC limits ARF-1 function, suggesting a mechanism for ILG activation via lipid metabolism, as part of a membrane stress response acting outside the ER. RNAi of selected ILGs uncovered defects in the secretion of two GFP reporters and the accumulation of a pathogen-responsive complement C1r/C1s, Uegf, Bmp1 (CUB) domain fusion protein. Our data argue that up-regulation of some ILGs is a coordinated response to changes in trafficking and may act to counteract stress on secretory function.
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Affiliation(s)
- Matthew J. Fanelli
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
| | - Christofer M. Welsh
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
- Morningside School of Biomedical Sciences, UMASS Chan Medical School, Worcester, MA, USA
| | - Dominique S. Lui
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
| | - Lorissa J. Smulan
- Department of Medicine, UMASS Chan Medical School, Worcester, MA, USA
| | - Amy K. Walker
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
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3
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Ravi, Kumar A, Bhattacharyya S, Singh J. Thiol reductive stress activates the hypoxia response pathway. EMBO J 2023; 42:e114093. [PMID: 37902464 PMCID: PMC10646554 DOI: 10.15252/embj.2023114093] [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: 03/22/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/31/2023] Open
Abstract
Owing to their capability to disrupt the oxidative protein folding environment in the endoplasmic reticulum (ER), thiol antioxidants, such as dithiothreitol (DTT), are used as ER-specific stressors. We recently showed that thiol antioxidants modulate the methionine-homocysteine cycle by upregulating an S-adenosylmethionine-dependent methyltransferase, rips-1, in Caenorhabditis elegans. However, the changes in cellular physiology induced by thiol stress that modulate the methionine-homocysteine cycle remain uncharacterized. Here, using forward genetic screens in C. elegans, we discover that thiol stress enhances rips-1 expression via the hypoxia response pathway. We demonstrate that thiol stress activates the hypoxia response pathway. The activation of the hypoxia response pathway by thiol stress is conserved in human cells. The hypoxia response pathway enhances thiol toxicity via rips-1 expression and confers protection against thiol toxicity via rips-1-independent mechanisms. Finally, we show that DTT might activate the hypoxia response pathway by producing hydrogen sulfide. Our studies reveal an intriguing interaction between thiol-mediated reductive stress and the hypoxia response pathway and challenge the current model that thiol antioxidant DTT disrupts only the ER milieu in the cell.
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Affiliation(s)
- Ravi
- Department of Biological SciencesIndian Institute of Science Education and ResearchMohaliIndia
| | - Ajay Kumar
- Department of BiophysicsPostgraduate Institute of Medical Education and ResearchChandigarhIndia
| | - Shalmoli Bhattacharyya
- Department of BiophysicsPostgraduate Institute of Medical Education and ResearchChandigarhIndia
| | - Jogender Singh
- Department of Biological SciencesIndian Institute of Science Education and ResearchMohaliIndia
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4
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Di Conza G, Ho PC, Cubillos-Ruiz JR, Huang SCC. Control of immune cell function by the unfolded protein response. Nat Rev Immunol 2023; 23:546-562. [PMID: 36755160 DOI: 10.1038/s41577-023-00838-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2023] [Indexed: 02/10/2023]
Abstract
Initiating and maintaining optimal immune responses requires high levels of protein synthesis, folding, modification and trafficking in leukocytes, which are processes orchestrated by the endoplasmic reticulum. Importantly, diverse extracellular and intracellular conditions can compromise the protein-handling capacity of this organelle, inducing a state of 'endoplasmic reticulum stress' that activates the unfolded protein response (UPR). Emerging evidence shows that physiological or pathological activation of the UPR can have effects on immune cell survival, metabolism, function and fate. In this Review, we discuss the canonical role of the adaptive UPR in immune cells and how dysregulation of this pathway in leukocytes contributes to diverse pathologies such as cancer, autoimmunity and metabolic disorders. Furthermore, we provide an overview as to how pharmacological approaches that modulate the UPR could be harnessed to control or activate immune cell function in disease.
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Affiliation(s)
- Giusy Di Conza
- Department of Fundamental Oncology, University of Lausanne, Lausanne, Switzerland
- Ludwig Institute for Cancer Research, University of Lausanne, Epalinges, Switzerland
| | - Ping-Chih Ho
- Department of Fundamental Oncology, University of Lausanne, Lausanne, Switzerland.
- Ludwig Institute for Cancer Research, University of Lausanne, Epalinges, Switzerland.
| | - Juan R Cubillos-Ruiz
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY, USA.
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA.
- Immunology and Microbial Pathogenesis Program, Graduate School of Medical Sciences, Weill Cornell Medicine, New York, NY, USA.
| | - Stanley Ching-Cheng Huang
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
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5
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Tang M, Ding G, Li L, Xiao G, Wang D. Exposure to polystyrene nanoparticles at predicted environmental concentrations enhances toxic effects of Acinetobacter johnsonii AC15 infection on Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115131. [PMID: 37315368 DOI: 10.1016/j.ecoenv.2023.115131] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 06/16/2023]
Abstract
Nanoplastics and microbial pathogens are both widely distributed in the environment; however, their combined toxicity remains largely unclear. Using Caenorhabditis elegans as an animal model, we examined the possible effect of exposure to polystyrene nanoparticle (PS-NP) in Acinetobacter johnsonii AC15 (a bacterial pathogen) infected animals. Exposure to PS-NP at the concentrations of 0.1-10 μg/L significantly enhanced the toxicity of Acinetobacter johnsonii AC15 infection on lifespan and locomotion behaviors. In addition, after exposure to 0.1-10 μg/L PS-NP, the accumulation of Acinetobacter johnsonii AC15 in body of nematodes was also increased. Meanwhile, the innate immune response indicated by the increase of antimicrobial gene expressions in Acinetobacter johnsonii AC15 infected nematodes was suppressed by exposure to 0.1-10 μg/L PS-NP. Moreover, expressions of egl-1, dbl-1, bar-1, daf-16, pmk-1, and elt-2 governing the bacterial infection and immunity in Acinetobacter johnsonii AC15 infected nematodes were further inhibited by exposure to 0.1-10 μg/L PS-NP. Therefore, our data suggested the possible exposure risk of nanoplastic at predicted environmental concentrations in enhancing the toxic effects of bacterial pathogens on environmental organisms.
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Affiliation(s)
- Mingfeng Tang
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China
| | - Guoying Ding
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China
| | - Liane Li
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China
| | - Guosheng Xiao
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China.
| | - Dayong Wang
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China; Medical School, Southeast University, Nanjing, China.
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6
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Moreno A, Taffet A, Tjahjono E, Anderson QL, Kirienko NV. Examining Sporadic Cancer Mutations Uncovers a Set of Genes Involved in Mitochondrial Maintenance. Genes (Basel) 2023; 14:1009. [PMID: 37239369 PMCID: PMC10218105 DOI: 10.3390/genes14051009] [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: 04/17/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
Mitochondria are key organelles for cellular health and metabolism and the activation of programmed cell death processes. Although pathways for regulating and re-establishing mitochondrial homeostasis have been identified over the past twenty years, the consequences of disrupting genes that regulate other cellular processes, such as division and proliferation, on affecting mitochondrial function remain unclear. In this study, we leveraged insights about increased sensitivity to mitochondrial damage in certain cancers, or genes that are frequently mutated in multiple cancer types, to compile a list of candidates for study. RNAi was used to disrupt orthologous genes in the model organism Caenorhabditis elegans, and a series of assays were used to evaluate these genes' importance for mitochondrial health. Iterative screening of ~1000 genes yielded a set of 139 genes predicted to play roles in mitochondrial maintenance or function. Bioinformatic analyses indicated that these genes are statistically interrelated. Functional validation of a sample of genes from this set indicated that disruption of each gene caused at least one phenotype consistent with mitochondrial dysfunction, including increased fragmentation of the mitochondrial network, abnormal steady-state levels of NADH or ROS, or altered oxygen consumption. Interestingly, RNAi-mediated knockdown of these genes often also exacerbated α-synuclein aggregation in a C. elegans model of Parkinson's disease. Additionally, human orthologs of the gene set showed enrichment for roles in human disorders. This gene set provides a foundation for identifying new mechanisms that support mitochondrial and cellular homeostasis.
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Affiliation(s)
| | | | | | | | - Natalia V. Kirienko
- Department of BioSciences, Rice University, 6100 Main St, MS140, Houston, TX 77005, USA; (A.M.); (A.T.); (E.T.); (Q.L.A.)
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7
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Singh J. ERASing endoplasmic reticulum stress: the faster, the better. Trends Cell Biol 2023; 33:179-181. [PMID: 36623997 DOI: 10.1016/j.tcb.2022.12.003] [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: 12/21/2022] [Accepted: 12/27/2022] [Indexed: 01/09/2023]
Abstract
The endoplasmic reticulum (ER) has evolved multiple mechanisms to maintain homeostasis under stress conditions. A recent study by Efstathiou et al. identified a novel mechanism of silencing ER-associated RNAs by the exogenous RNA interference pathway. This adaptive response reduces protein flux in the ER under stressful conditions.
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Affiliation(s)
- Jogender Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Punjab 140306, India.
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8
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Celik C, Lee SYT, Yap WS, Thibault G. Endoplasmic reticulum stress and lipids in health and diseases. Prog Lipid Res 2023; 89:101198. [PMID: 36379317 DOI: 10.1016/j.plipres.2022.101198] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/03/2022] [Accepted: 11/09/2022] [Indexed: 11/14/2022]
Abstract
The endoplasmic reticulum (ER) is a complex and dynamic organelle that regulates many cellular pathways, including protein synthesis, protein quality control, and lipid synthesis. When one or multiple ER roles are dysregulated and saturated, the ER enters a stress state, which, in turn, activates the highly conserved unfolded protein response (UPR). By sensing the accumulation of unfolded proteins or lipid bilayer stress (LBS) at the ER, the UPR triggers pathways to restore ER homeostasis and eventually induces apoptosis if the stress remains unresolved. In recent years, it has emerged that the UPR works intimately with other cellular pathways to maintain lipid homeostasis at the ER, and so does at cellular levels. Lipid distribution, along with lipid anabolism and catabolism, are tightly regulated, in part, by the ER. Dysfunctional and overwhelmed lipid-related pathways, independently or in combination with ER stress, can have reciprocal effects on other cellular functions, contributing to the development of diseases. In this review, we summarize the current understanding of the UPR in response to proteotoxic stress and LBS and the breadth of the functions mitigated by the UPR in different tissues and in the context of diseases.
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Affiliation(s)
- Cenk Celik
- School of Biological Sciences, Nanyang Technological University, Singapore
| | | | - Wei Sheng Yap
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore; Mechanobiology Institute, National University of Singapore, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore.
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9
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G G, Singh J. Dithiothreitol causes toxicity in C. elegans by modulating the methionine-homocysteine cycle. eLife 2022; 11:76021. [PMID: 35438636 PMCID: PMC9090326 DOI: 10.7554/elife.76021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/17/2022] [Indexed: 11/13/2022] Open
Abstract
The redox reagent dithiothreitol (DTT) causes stress in the endoplasmic reticulum (ER) by disrupting its oxidative protein folding environment, which results in the accumulation and misfolding of the newly synthesized proteins. DTT may potentially impact cellular physiology by ER-independent mechanisms; however, such mechanisms remain poorly characterized. Using the nematode model Caenorhabditis elegans, here we show that DTT toxicity is modulated by the bacterial diet. Specifically, the dietary component vitamin B12 alleviates DTT toxicity in a methionine synthase-dependent manner. Using a forward genetic screen, we discover that loss-of-function of R08E5.3, an S-adenosylmethionine (SAM)-dependent methyltransferase, confers DTT resistance. DTT upregulates R08E5.3 expression and modulates the activity of the methionine–homocysteine cycle. Employing genetic and biochemical studies, we establish that DTT toxicity is a result of the depletion of SAM. Finally, we show that a functional IRE-1/XBP-1 unfolded protein response pathway is required to counteract toxicity at high, but not low, DTT concentrations. Animal and plant cells synthesize a significant fraction of their proteins on a structure known as the endoplasmic reticulum. Researchers often use the molecule dithiothreitol to specifically target this compartment and learn more about its role. The toxin works by disturbing the complex chemical environment present in the reticulum, which is required for the proteins to assemble properly. However, it is important to clarify whether dithiothreitol could also affect other parts of the cell, as this could give rise to misleading results. To explore this possibility, Gokul G and Jogender Singh studied the effects of dithiothreitol on the millimetre-long roundworm Caenorhabditis elegans. Their experiments revealed that vitamin B12 could protect against dithiothreitol toxicity via a complex cascade of molecular events which reduced the levels of an important regulatory molecule known as S-adenosylmethionine. Crucially, the chemical reactions that dithiothreitol targeted took place outside the reticulum, suggesting that the toxin impairs processes in the wider cell. These results suggest that dithiothreitol should be reconsidered for use in endoplasmic reticulum studies. However, they also imply that this toxin could be beneficial in small doses, as a reduced concentration of S-adenosylmethionine increases lifespan and health in a variety of organisms.
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Affiliation(s)
- Gokul G
- Indian Institute of Science Education and Research, Bhopal, Bhopal, India
| | - Jogender Singh
- Indian Institute of Science Education and Research, Mohali, Mohali, India
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10
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Nath AS, Parsons BD, Makdissi S, Chilvers RL, Mu Y, Weaver CM, Euodia I, Fitze KA, Long J, Scur M, Mackenzie DP, Makrigiannis AP, Pichaud N, Boudreau LH, Simmonds AJ, Webber CA, Derfalvi B, Hammon Y, Rachubinski RA, Di Cara F. Modulation of the cell membrane lipid milieu by peroxisomal β-oxidation induces Rho1 signaling to trigger inflammatory responses. Cell Rep 2022; 38:110433. [PMID: 35235794 DOI: 10.1016/j.celrep.2022.110433] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 12/21/2021] [Accepted: 02/01/2022] [Indexed: 12/11/2022] Open
Abstract
Phagocytosis, signal transduction, and inflammatory responses require changes in lipid metabolism. Peroxisomes have key roles in fatty acid homeostasis and in regulating immune function. We find that Drosophila macrophages lacking peroxisomes have perturbed lipid profiles, which reduce host survival after infection. Using lipidomic, transcriptomic, and genetic screens, we determine that peroxisomes contribute to the cell membrane glycerophospholipid composition necessary to induce Rho1-dependent signals, which drive cytoskeletal remodeling during macrophage activation. Loss of peroxisome function increases membrane phosphatidic acid (PA) and recruits RhoGAPp190 during infection, inhibiting Rho1-mediated responses. Peroxisome-glycerophospholipid-Rho1 signaling also controls cytoskeleton remodeling in mouse immune cells. While high levels of PA in cells without peroxisomes inhibit inflammatory phenotypes, large numbers of peroxisomes and low amounts of cell membrane PA are features of immune cells from patients with inflammatory Kawasaki disease and juvenile idiopathic arthritis. Our findings reveal potential metabolic markers and therapeutic targets for immune diseases and metabolic disorders.
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Affiliation(s)
- Anu S Nath
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Brendon D Parsons
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Stephanie Makdissi
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Rebecca L Chilvers
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Yizhu Mu
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Ceileigh M Weaver
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Irene Euodia
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Katherine A Fitze
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Juyang Long
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Michal Scur
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Duncan P Mackenzie
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Andrew P Makrigiannis
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Nicolas Pichaud
- Université de Moncton, Department of Chemistry and Biochemistry, Moncton, NB E1A 3E9, Canada; New Brunswick Centre for Precision Medicine (NBCPM), Moncton, NB E1A 3E9, Canada
| | - Luc H Boudreau
- Université de Moncton, Department of Chemistry and Biochemistry, Moncton, NB E1A 3E9, Canada; New Brunswick Centre for Precision Medicine (NBCPM), Moncton, NB E1A 3E9, Canada
| | - Andrew J Simmonds
- University of Alberta, Department of Cell Biology, Edmonton, AB T6G 2H7, Canada
| | - Christine A Webber
- University of Alberta, Department of Cell Biology, Edmonton, AB T6G 2H7, Canada
| | - Beata Derfalvi
- Dalhousie University, Department of Pediatrics, Halifax, NS B3K 6R8, Canada
| | - Yannick Hammon
- INSERM au Centre d'Immunologie de Marseille Luminy, Marseille 13288, France
| | | | - Francesca Di Cara
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada; Dalhousie University, Department of Pediatrics, Halifax, NS B3K 6R8, Canada.
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11
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Filipowicz A, Lalsiamthara J, Aballay A. TRPM channels mediate learned pathogen avoidance following intestinal distention. eLife 2021; 10:65935. [PMID: 34032213 PMCID: PMC8177887 DOI: 10.7554/elife.65935] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
Upon exposure to harmful microorganisms, hosts engage in protective molecular and behavioral immune responses, both of which are ultimately regulated by the nervous system. Using the nematode Caenorhabditis elegans, we show that ingestion of Enterococcus faecalis leads to a fast pathogen avoidance behavior that results in aversive learning. We have identified multiple sensory mechanisms involved in the regulation of avoidance of E. faecalis. The G-protein coupled receptor NPR-1-dependent oxygen-sensing pathway opposes this avoidance behavior, while an ASE neuron-dependent pathway and an AWB and AWC neuron-dependent pathway are directly required for avoidance. Colonization of the anterior part of the intestine by E. faecalis leads to AWB and AWC mediated olfactory aversive learning. Finally, two transient receptor potential melastatin (TRPM) channels, GON-2 and GTL-2, mediate this newly described rapid pathogen avoidance. These results suggest a mechanism by which TRPM channels may sense the intestinal distension caused by bacterial colonization to elicit pathogen avoidance and aversive learning by detecting changes in host physiology.
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Affiliation(s)
- Adam Filipowicz
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
| | - Jonathan Lalsiamthara
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
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12
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Otarigho B, Aballay A. Immunity-longevity tradeoff neurally controlled by GABAergic transcription factor PITX1/UNC-30. Cell Rep 2021; 35:109187. [PMID: 34038721 PMCID: PMC8227953 DOI: 10.1016/j.celrep.2021.109187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/01/2021] [Accepted: 05/06/2021] [Indexed: 12/15/2022] Open
Abstract
A body of evidence indicates that metazoan immune and aging pathways are largely interconnected, but the mechanisms involved in their homeostatic control remain unclear. In this study, we find that the PITX (paired-like homeodomain) transcription factor UNC-30 controls the tradeoff between immunity and longevity from the nervous system in Caenorhabditis elegans. PITX/UNC-30 functional loss enhances immunity in a GATA/ELT-2- and p38 MAPK/PMK-1-dependent manner and reduced longevity by activating MXD/MDL-1 and the C2H2-type zinc finger transcription factor PQM-1. The immune inhibitory and longevity stimulatory functions of PITX/UNC-30 require the sensory neuron ASG and a signaling pathway controlled by NPR-1, which is a G protein-coupled receptor related to mammalian neuropeptide Y receptors. Our findings uncover a suppressive role of GABAergic signaling in the neural control of a biological tradeoff where energy is allocated toward immunity at the expense of longevity.
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Affiliation(s)
- Benson Otarigho
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA.
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13
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Hong C, Lalsiamthara J, Ren J, Sang Y, Aballay A. Microbial colonization induces histone acetylation critical for inherited gut-germline-neural signaling. PLoS Biol 2021; 19:e3001169. [PMID: 33788830 PMCID: PMC8041202 DOI: 10.1371/journal.pbio.3001169] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 04/12/2021] [Accepted: 03/04/2021] [Indexed: 11/22/2022] Open
Abstract
The gut-neural axis plays a critical role in the control of several physiological processes, including the communication of signals from the microbiome to the nervous system, which affects learning, memory, and behavior. However, the pathways involved in gut-neural signaling of gut-governed behaviors remain unclear. We found that the intestinal distension caused by the bacterium Pseudomonas aeruginosa induces histone H4 Lys8 acetylation (H4K8ac) in the germline of Caenorhabditis elegans, which is required for both a bacterial aversion behavior and its transmission to the next generation. We show that induction of H4K8ac in the germline is essential for bacterial aversion and that a 14-3-3 chaperone protein family member, PAR-5, is required for H4K8ac. Our findings highlight a role for H4K8ac in the germline not only in the intergenerational transmission of pathogen avoidance but also in the transmission of pathogenic cues that travel through the gut-neural axis to control the aversive behavior. This study shows that microbial colonization of the intestine of the nematode Caenorhabditis elegans intestine induces changes in the germline that not only influence the inheritance of pathogen avoidance but also the transmission of pathogenic cues that travel through the gut-neural axis to control aversive behavior.
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Affiliation(s)
- Chunlan Hong
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jonathan Lalsiamthara
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jie Ren
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Yu Sang
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Alejandro Aballay
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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14
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Xu J, Taubert S. Beyond Proteostasis: Lipid Metabolism as a New Player in ER Homeostasis. Metabolites 2021; 11:52. [PMID: 33466824 PMCID: PMC7830277 DOI: 10.3390/metabo11010052] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/04/2021] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
Biological membranes are not only essential barriers that separate cellular and subcellular structures, but also perform other critical functions such as the initiation and propagation of intra- and intercellular signals. Each membrane-delineated organelle has a tightly regulated and custom-made membrane lipid composition that is critical for its normal function. The endoplasmic reticulum (ER) consists of a dynamic membrane network that is required for the synthesis and modification of proteins and lipids. The accumulation of unfolded proteins in the ER lumen activates an adaptive stress response known as the unfolded protein response (UPR-ER). Interestingly, recent findings show that lipid perturbation is also a direct activator of the UPR-ER, independent of protein misfolding. Here, we review proteostasis-independent UPR-ER activation in the genetically tractable model organism Caenorhabditis elegans. We review the current knowledge on the membrane lipid composition of the ER, its impact on organelle function and UPR-ER activation, and its potential role in human metabolic diseases. Further, we summarize the bi-directional interplay between lipid metabolism and the UPR-ER. We discuss recent progress identifying the different respective mechanisms by which disturbed proteostasis and lipid bilayer stress activate the UPR-ER. Finally, we consider how genetic and metabolic disturbances may disrupt ER homeostasis and activate the UPR and discuss how using -omics-type analyses will lead to more comprehensive insights into these processes.
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Affiliation(s)
- Jiaming Xu
- Graduate Program in Cell and Developmental Biology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Healthy Starts Theme, British Columbia Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Stefan Taubert
- Graduate Program in Cell and Developmental Biology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Healthy Starts Theme, British Columbia Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
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15
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Sun W, Li H, Zhao Y, Bai L, Qin Y, Wang Q, Li W. Distinct vitellogenin domains differentially regulate immunological outcomes in invertebrates. J Biol Chem 2021; 296:100060. [PMID: 33177064 PMCID: PMC7949091 DOI: 10.1074/jbc.ra120.015686] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/05/2020] [Accepted: 11/11/2020] [Indexed: 11/19/2022] Open
Abstract
The classical role of Vitellogenin (Vg) is providing energy reserves for developing embryos, but its roles appear to extend beyond this nutritional function, and its importance in host immune defense is garnering increasing research attention. However, Vg-regulated immunological functions are dependent on three different domains within different species and remain poorly understood. In the present study, we confirmed three conserved VG domains-LPD_N, DUF1943, and VWD-in the Chinese mitten crab (Eriocheir sinensis), highlighting functional similarities of Vg in vertebrates and invertebrates. Of these three domains, DUF1943 and VWD showed definitive bacterial binding activity via interaction with the signature components on microbial surfaces, but this activity was not exhibited by the LPD_N domain. Antibacterial assays indicated that only the VWD domain inhibits bacterial proliferation, and this function may be conserved between different species due to the conserved amino acid residues. To further explore the relationship between Vg and polymeric immunoglobulin receptor (pIgR), we expressed EspIgR and the three E. sinensis Vg (EsVg) domains in HEK293T cells, and coimmunoprecipitation assay demonstrated that only the DUF1943 domain interacts with EspIgR. Subsequent experiments demonstrated that EsVg regulates hemocyte phagocytosis by binding with EspIgR through the DUF1943 domain, thus promoting bacterial clearance and protecting the host from bacterial infection. To the best of our knowledge, our work is the first to report distinct domains in Vg inducing different immunological outcomes in invertebrates, providing new evidence that pIgR acts as a phagocytic receptor for Vg.
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Affiliation(s)
- Weikang Sun
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Hao Li
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Yuehong Zhao
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Longwei Bai
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Yukai Qin
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Qun Wang
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Weiwei Li
- Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China.
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16
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Lee SK. Endoplasmic Reticulum Homeostasis and Stress Responses in Caenorhabditis elegans. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:279-303. [PMID: 34050871 DOI: 10.1007/978-3-030-67696-4_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The unfolded protein response (UPR) is an evolutionarily conserved adaptive regulatory pathway that alleviates protein-folding defects in the endoplasmic reticulum (ER). Physiological demands, environmental perturbations and pathological conditions can cause accumulation of unfolded proteins in the ER and the stress signal is transmitted to the nucleus to turn on a series of genes to respond the challenge. In metazoan, the UPR pathways consisted of IRE1/XBP1, PEK-1 and ATF6, which function in parallel and downstream transcriptional activation triggers the proteostasis networks consisting of molecular chaperones, protein degradation machinery and other stress response pathways ((Labbadia J, Morimoto RI, F1000Prime Rep 6:7, 2014); (Shen X, Ellis RE, Lee K, Annu Rev Biochem 28:893-903, 2014)). The integrated responses act on to resolve the ER stress by increasing protein folding capacity, attenuating ER-loading translation, activating ER-associated proteasomal degradation (ERAD), and regulating IRE1-dependent decay of mRNA (RIDD). Therefore, the effective UPR to internal and external causes is linked to the multiple pathophysiological conditions such as aging, immunity, and neurodegenerative diseases. Recent development in the research of the UPR includes cell-nonautonomous features of the UPR, interplay between the UPR and other stress response pathways, unconventional UPR inducers, and noncanonical UPR independent of the three major branches, originated from multiple cellular and molecular machineries in addition to ER. Caenorhabditis elegans model system has critically contributed to these unprecedented aspects of the ER UPR and broadens the possible therapeutic targets to treat the ER-stress associated human disorders and time-dependent physiological deterioration of aging.
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Affiliation(s)
- Sun-Kyung Lee
- Department of Life Science, Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea.
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17
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Harnessing the power of genetics: fast forward genetics in Caenorhabditis elegans. Mol Genet Genomics 2020; 296:1-20. [PMID: 32888055 DOI: 10.1007/s00438-020-01721-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/27/2020] [Indexed: 12/23/2022]
Abstract
Forward genetics is a powerful tool to unravel molecular mechanisms of diverse biological processes. The success of genetic screens primarily relies on the ease of genetic manipulation of an organism and the availability of a plethora of genetic tools. The roundworm Caenorhabditis elegans has been one of the favorite models for genetic studies due to its hermaphroditic lifestyle, ease of maintenance, and availability of various genetic manipulation tools. The strength of C. elegans genetics is highlighted by the leading role of this organism in the discovery of several conserved biological processes. In this review, the principles and strategies for forward genetics in C. elegans are discussed. Further, the recent advancements that have drastically accelerated the otherwise time-consuming process of mutation identification, making forward genetic screens a method of choice for understanding biological functions, are discussed. The emphasis of the review has been on providing practical and conceptual pointers for designing genetic screens that will identify mutations, specifically disrupting the biological processes of interest.
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Integrated transcriptome and phosphoproteome analyses reveal that fads2 is critical for maintaining body LC-PUFA homeostasis. J Proteomics 2020; 229:103967. [PMID: 32891890 DOI: 10.1016/j.jprot.2020.103967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 08/04/2020] [Accepted: 08/31/2020] [Indexed: 11/21/2022]
Abstract
Fatty acid desaturate 2 (Fads2) is associated with many chronic diseases. Nevertheless, comprehensive researches on its role have not been performed. We here conducted an integrated analysis of long-chain polyunsaturated fatty acid (LC-PUFA) metabolism of fads2-deletion zebrafish (fads2-/-) by transcriptomics, proteomics and phosphoproteomics. Compared with wild type zebrafish (WT), fads2-/- showed significantly higher contents of hepatic linoleic acid (all-cis-9,12-C18:2), α-linolenic acid (all-cis-9,12,15-C18:3) and docosapetaenoic acid (all-cis-7,10,13,16,19-C22:5), and lower contents of γ-linolenic acid (all-cis-6,9,12-C18:3), stearidonic acid (all-cis-6,9,12,15-C18:4) and docosahexaenoic acid (all-cis-4,7,10,13,16,19-C22:6), accompanied by an increased n-6/n-3 PUFA level. In total, we identified 1608 differentially expressed genes (DEGs), 209 differentially expressed proteins (DEPs) and 153 differentially expressed phosphorylated proteins (DEPPs) with 190 sites between fads2-/- and WT. Transcriptome and proteome analysis simultaneously aggregated these DEGs and DEPs into LC-PUFA synthesis and PPAR signaling pathways. Further interaction network analysis of the DEPPs showed that spliceosome and protein processing in endoplasmic reticulum pathway were critical groups. Additionally, we determined seven highly phosphorylated kinases and a highly expressed phosphatase in fads2-/- zebrafish. These results give insights into the mechanism by which fads2 affects metabolic disease occurrence, and provide datasets for target selections for human disease treatment. SIGNIFICANCE: Balanced LC-PUFA composition was deeply associated with body health, while changes of LC-PUFAs usually induced serious diseases such as cardiovascular disease, type 2 diabetes and inflammatory disease. Fatty acid desaturase 2 (Fads2), subordinating to the fatty acid desaturase protein family, catalyzes the first desaturation reaction in LC-PUFA synthesis. Although Fads2 is associated with many chronic diseases including metabolic abnormalities, type 2 diabetes and obesity, comprehensive researches on its role have not been performed. On the basis of the integrated transcriptome, proteome and phosphoproteome analysis, we identified that fads2 was critical for maintaining body LC-PUFA homeostasis. Moreover, the crucial pathways including PPAR signaling pathway, spliceosome and protein processing in endoplasmic reticulum pathway, and candidate kinase targets associated with LC-PUFA metabolism were determined. These findings will contribute to the revealing of the mechanism and supply possible datasets for target selection for human disease treatment.
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Metcalf MG, Higuchi-Sanabria R, Garcia G, Tsui CK, Dillin A. Beyond the cell factory: Homeostatic regulation of and by the UPR ER. SCIENCE ADVANCES 2020; 6:eabb9614. [PMID: 32832649 PMCID: PMC7439504 DOI: 10.1126/sciadv.abb9614] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 06/02/2020] [Indexed: 05/02/2023]
Abstract
The endoplasmic reticulum (ER) is commonly referred to as the factory of the cell, as it is responsible for a large amount of protein and lipid synthesis. As a membrane-bound organelle, the ER has a distinct environment that is ideal for its functions in synthesizing these primary cellular components. Many different quality control machineries exist to maintain ER stability under the stresses associated with synthesizing, folding, and modifying complex proteins and lipids. The best understood of these mechanisms is the unfolded protein response of the ER (UPRER), in which transmembrane proteins serve as sensors, which trigger a coordinated transcriptional response of genes dedicated for mitigating the stress. As the name suggests, the UPRER is most well described as a functional response to protein misfolding stress. Here, we focus on recent findings and emerging themes in additional roles of the UPRER outside of protein homeostasis, including lipid homeostasis, autophagy, apoptosis, and immunity.
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DAF-16 and SMK-1 Contribute to Innate Immunity During Adulthood in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2020; 10:1521-1539. [PMID: 32161087 PMCID: PMC7202018 DOI: 10.1534/g3.120.401166] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Aging is accompanied by a progressive decline in immune function termed "immunosenescence". Deficient surveillance coupled with the impaired function of immune cells compromises host defense in older animals. The dynamic activity of regulatory modules that control immunity appears to underlie age-dependent modifications to the immune system. In the roundworm Caenorhabditis elegans levels of PMK-1 p38 MAP kinase diminish over time, reducing the expression of immune effectors that clear bacterial pathogens. Along with the PMK-1 pathway, innate immunity in C. elegans is regulated by the insulin signaling pathway. Here we asked whether DAF-16, a Forkhead box (FOXO) transcription factor whose activity is inhibited by insulin signaling, plays a role in host defense later in life. While in younger C. elegans DAF-16 is inactive unless stimulated by environmental insults, we found that even in the absence of acute stress the transcriptional activity of DAF-16 increases in an age-dependent manner. Beginning in the reproductive phase of adulthood, DAF-16 upregulates a subset of its transcriptional targets, including genes required to kill ingested microbes. Accordingly, DAF-16 has little to no role in larval immunity, but functions specifically during adulthood to confer resistance to bacterial pathogens. We found that DAF-16-mediated immunity in adults requires SMK-1, a regulatory subunit of the PP4 protein phosphatase complex. Our data suggest that as the function of one branch of the innate immune system of C. elegans (PMK-1) declines over time, DAF-16-mediated immunity ramps up to become the predominant means of protecting adults from infection, thus reconfiguring immunity later in life.
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21
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Jeong DE, Lee Y, Ham S, Lee D, Kwon S, Park HEH, Hwang SY, Yoo JY, Roh TY, Lee SJV. Inhibition of the oligosaccharyl transferase in Caenorhabditis elegans that compromises ER proteostasis suppresses p38-dependent protection against pathogenic bacteria. PLoS Genet 2020; 16:e1008617. [PMID: 32130226 PMCID: PMC7055741 DOI: 10.1371/journal.pgen.1008617] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 01/20/2020] [Indexed: 12/14/2022] Open
Abstract
The oligosaccharyl transferase (OST) protein complex mediates the N-linked glycosylation of substrate proteins in the endoplasmic reticulum (ER), which regulates stability, activity, and localization of its substrates. Although many OST substrate proteins have been identified, the physiological role of the OST complex remains incompletely understood. Here we show that the OST complex in C. elegans is crucial for ER protein homeostasis and defense against infection with pathogenic bacteria Pseudomonas aeruginosa (PA14), via immune-regulatory PMK-1/p38 MAP kinase. We found that genetic inhibition of the OST complex impaired protein processing in the ER, which in turn up-regulated ER unfolded protein response (UPRER). We identified vitellogenin VIT-6 as an OST-dependent glycosylated protein, critical for maintaining survival on PA14. We also showed that the OST complex was required for up-regulation of PMK-1 signaling upon infection with PA14. Our study demonstrates that an evolutionarily conserved OST complex, crucial for ER homeostasis, regulates host defense mechanisms against pathogenic bacteria. N-linked glycosylation is essential for the function of various proteins, but its effects on physiology at an organism level remain poorly understood. Using the roundworm Caenorhabditis elegans, we show that the oligosaccharyl transferase (OST) complex, which mediates the N-glycosylation of substrate proteins in the ER, reduces susceptibility to pathogenic bacteria, Pseudomonas aeruginosa. We find that OST enhances defense against P. aeruginosa via maintenance of ER unfolded protein response (UPRER) and up-regulation of cytosolic p38 MAP kinase signaling. Our findings propose an intriguing model for the organellar crosstalk between the ER and the cytosol in host defense mechanisms. Because the OST complex components are highly conserved among eukaryotes, our study on the regulation of cellular signaling and C. elegans physiology by the OST complex will provide an insight into the function of its mammalian counterpart.
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Affiliation(s)
- Dae-Eun Jeong
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, South Korea
| | - Yujin Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, South Korea
| | - Seokjin Ham
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, South Korea
| | - Dongyeop Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, South Korea
| | - Sujeong Kwon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, South Korea
| | - Hae-Eun H. Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, South Korea
| | - Sun-Young Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, South Korea
| | - Joo-Yeon Yoo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, South Korea
| | - Tae-Young Roh
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, South Korea
| | - Seung-Jae V. Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, South Korea
- * E-mail:
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22
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Host Mucin Is Exploited by Pseudomonas aeruginosa To Provide Monosaccharides Required for a Successful Infection. mBio 2020; 11:mBio.00060-20. [PMID: 32127446 PMCID: PMC7064748 DOI: 10.1128/mbio.00060-20] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
One of the primary functions of the mucosal barrier, found lining epithelial cells, is to serve as a first-line of defense against microbial pathogens. The major structural components of mucus are heavily glycosylated proteins called mucins. Mucins are key components of the innate immune system as they aid in the clearance of pathogens and can decrease pathogen virulence. It has also been recently reported that individual mucins and derived glycans can attenuate the virulence of the human pathogen Pseudomonas aeruginosa Here, we show data indicating that mucins not only play a role in host defense but that they can also be subverted by P. aeruginosa to cause disease. We found that the mucin MUL-1 and mucin-derived monosaccharides N-acetyl-galactosamine and N-acetylglucosamine are required for P. aeruginosa killing of Caenorhabditis elegans We also found that the defective adhesion of P. aeruginosa to human lung alveolar epithelial cells, deficient in the mucin MUC1, can be reversed by the addition of individual monosaccharides. The monosaccharides identified in this study are found in a wide range of organisms where they act as host factors required for bacterial pathogenesis. While mucins in C. elegans lack sialic acid caps, which makes their monosaccharides readily available, they are capped in other species. Pathogens such as P. aeruginosa that lack sialidases may rely on enzymes from other bacteria to utilize mucin-derived monosaccharides.IMPORTANCE One of the first lines of defense present at mucosal epithelial tissues is mucus, which is a highly viscous material formed by mucin glycoproteins. Mucins serve various functions, but importantly they aid in the clearance of pathogens and debris from epithelial barriers and serve as innate immune factors. In this study, we describe a requirement of host monosaccharides, likely derived from host mucins, for the ability of Pseudomonas aeruginosa to colonize the intestine and ultimately cause death in Caenorhabditis elegans We also demonstrate that monosaccharides alter the ability of bacteria to bind to both Caenorhabditis elegans intestinal cells and human lung alveolar epithelial cells, suggesting that there are conserved mechanisms underlying host-pathogen interactions in a range of organisms. By gaining a better understanding of pathogen-mucin interactions, we can develop better approaches to protect against pathogen infection.
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Singh J, Aballay A. Intestinal infection regulates behavior and learning via neuroendocrine signaling. eLife 2019; 8:e50033. [PMID: 31674907 PMCID: PMC6884406 DOI: 10.7554/elife.50033] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/31/2019] [Indexed: 12/14/2022] Open
Abstract
The recognition of pathogens and subsequent activation of defense responses are critical for the survival of organisms. The nematode Caenorhabditis elegans recognizes pathogenic bacteria and elicits defense responses by activating immune pathways and pathogen avoidance. Here we show that chemosensation of phenazines produced by pathogenic Pseudomonas aeruginosa, which leads to rapid activation of DAF-7/TGF-β in ASJ neurons, is insufficient for the elicitation of pathogen avoidance behavior. Instead, intestinal infection and bloating of the lumen, which depend on the virulence of P. aeruginosa, regulates both pathogen avoidance and aversive learning by modulating not only the DAF-7/TGF-β pathway but also the G-protein coupled receptor NPR-1 pathway, which also controls aerotaxis behavior. Modulation of these neuroendocrine pathways by intestinal infection serves as a systemic feedback that enables animals to avoid virulent bacteria. These results reveal how feedback from the intestine during infection can modulate the behavior, learning, and microbial perception of the host.
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Affiliation(s)
- Jogender Singh
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandUnited States
| | - Alejandro Aballay
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandUnited States
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24
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Hartman JH, Richie CT, Gordon KL, Mello DF, Castillo P, Zhu A, Wang Y, Hoffer BJ, Sherwood DR, Meyer JN, Harvey BK. MANF deletion abrogates early larval Caenorhabditis elegans stress response to tunicamycin and Pseudomonas aeruginosa. Eur J Cell Biol 2019; 98:151043. [PMID: 31138438 DOI: 10.1016/j.ejcb.2019.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 04/16/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) is the only human neurotrophic factor with an evolutionarily-conserved C. elegans homolog, Y54G2A.23 or manf-1. MANF is a small, soluble, endoplasmic-reticulum (ER)-resident protein that is secreted upon ER stress and promotes survival of target cells such as neurons. However, the role of MANF in ER stress and its mechanism of cellular protection are not clear and the function of MANF in C. elegans is only beginning to emerge. In this study, we show that depletion of C. elegans manf-1 causes a slight decrease in lifespan and brood size; furthermore, combined depletion of manf-1 and the IRE-1/XBP-1 ER stress/UPR pathway resulted in sterile animals that did not produce viable progeny. We demonstrate upregulation of markers of ER stress in L1 larval nematodes, as measured by hsp-3 and hsp-4 transcription, upon depletion of manf-1 by RNAi or mutation; however, there was no difference in tunicamycin-induced expression of hsp-3 and hsp-4 between wild-type and MANF-deficient worms. Surprisingly, larval growth arrest observed in wild-type nematodes reared on tunicamycin is completely prevented in the manf-1 (tm3603) mutant. Transcriptional microarray analysis revealed that manf-1 mutant L1 larvae exhibit a novel modulation of innate immunity genes in response to tunicamycin. The hypothesis that manf-1 negatively regulates the innate immunity pathway is supported by our finding that the development of manf-1 mutant larvae compared to wild-type larvae is not inhibited by growth on P. aeruginosa. Together, our data represent the first characterization of C. elegans MANF as a key modulator of organismal ER stress and immunity.
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Affiliation(s)
- Jessica H Hartman
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, United States of America
| | - Christopher T Richie
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, United States of America
| | - Kacy L Gordon
- Department of Biology, Regeneration Next, Duke University, Durham, NC, 27708, United States of America
| | - Danielle F Mello
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, United States of America
| | - Priscila Castillo
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, United States of America
| | - April Zhu
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, United States of America
| | - Yun Wang
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, United States of America
| | - Barry J Hoffer
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, United States of America
| | - David R Sherwood
- Department of Biology, Regeneration Next, Duke University, Durham, NC, 27708, United States of America
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, United States of America
| | - Brandon K Harvey
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, United States of America.
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Singh J, Aballay A. Microbial Colonization Activates an Immune Fight-and-Flight Response via Neuroendocrine Signaling. Dev Cell 2019; 49:89-99.e4. [PMID: 30827896 DOI: 10.1016/j.devcel.2019.02.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/26/2018] [Accepted: 01/31/2019] [Indexed: 01/01/2023]
Abstract
The ability to distinguish harmful and beneficial microbes is critical for the survival of an organism. Here, we show that bloating of the intestinal lumen of Caenorhabditis elegans caused by microbial colonization elicits a microbial aversion behavior. Bloating of the intestinal lumen also activates a broad innate immune response, even in the absence of bacterial pathogens or live bacteria. Neuroendocrine pathway genes are upregulated by intestinal bloating and are required for microbial aversion behavior. We propose that microbial colonization and bloating of the intestine may be perceived as a danger signal that activates an immune fight-and-flight response. These results reveal how inputs from the intestine can aid in the recognition of a broad range of microbes and modulate host behavior via neuroendocrine signaling.
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Affiliation(s)
- Jogender Singh
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
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26
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Denzel MS, Lapierre LR, Mack HID. Emerging topics in C. elegans aging research: Transcriptional regulation, stress response and epigenetics. Mech Ageing Dev 2018; 177:4-21. [PMID: 30134144 PMCID: PMC6696993 DOI: 10.1016/j.mad.2018.08.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/13/2022]
Abstract
Key discoveries in aging research have been made possible with the use of model organisms. Caenorhabditis elegans is a short-lived nematode that has become a well-established system to study aging. The practicality and powerful genetic manipulations associated with this metazoan have revolutionized our ability to understand how organisms age. 25 years after the publication of the discovery of the daf-2 gene as a genetic modifier of lifespan, C. elegans remains as relevant as ever in the quest to understand the process of aging. Nematode aging research has proven useful in identifying transcriptional regulators, small molecule signals, cellular mechanisms, epigenetic modifications associated with stress resistance and longevity, and lifespan-extending compounds. Here, we review recent discoveries and selected topics that have emerged in aging research using this incredible little worm.
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Affiliation(s)
- Martin S Denzel
- Max Planck Institute for Biology of Ageing, Cologne, Germany.
| | - Louis R Lapierre
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA.
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