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Muthaiyan Shanmugam M, Chaudhuri J, Sellegounder D, Sahu AK, Guha S, Chamoli M, Hodge B, Bose N, Roberts C, Farrera DO, Lithgow G, Sarpong R, Galligan JJ, Kapahi P. Methylglyoxal-derived hydroimidazolone, MG-H1, increases food intake by altering tyramine signaling via the GATA transcription factor ELT-3 in Caenorhabditis elegans. eLife 2023; 12:e82446. [PMID: 37728328 PMCID: PMC10611433 DOI: 10.7554/elife.82446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/19/2023] [Indexed: 09/21/2023] Open
Abstract
The Maillard reaction, a chemical reaction between amino acids and sugars, is exploited to produce flavorful food ubiquitously, from the baking industry to our everyday lives. However, the Maillard reaction also occurs in all cells, from prokaryotes to eukaryotes, forming advanced glycation end-products (AGEs). AGEs are a heterogeneous group of compounds resulting from the irreversible reaction between biomolecules and α-dicarbonyls (α-DCs), including methylglyoxal (MGO), an unavoidable byproduct of anaerobic glycolysis and lipid peroxidation. We previously demonstrated that Caenorhabditis elegans mutants lacking the glod-4 glyoxalase enzyme displayed enhanced accumulation of α-DCs, reduced lifespan, increased neuronal damage, and touch hypersensitivity. Here, we demonstrate that glod-4 mutation increased food intake and identify that MGO-derived hydroimidazolone, MG-H1, is a mediator of the observed increase in food intake. RNAseq analysis in glod-4 knockdown worms identified upregulation of several neurotransmitters and feeding genes. Suppressor screening of the overfeeding phenotype identified the tdc-1-tyramine-tyra-2/ser-2 signaling as an essential pathway mediating AGE (MG-H1)-induced feeding in glod-4 mutants. We also identified the elt-3 GATA transcription factor as an essential upstream regulator for increased feeding upon accumulation of AGEs by partially controlling the expression of tdc-1 gene. Furthermore, the lack of either tdc-1 or tyra-2/ser-2 receptors suppresses the reduced lifespan and rescues neuronal damage observed in glod-4 mutants. Thus, in C. elegans, we identified an elt-3 regulated tyramine-dependent pathway mediating the toxic effects of MG-H1 AGE. Understanding this signaling pathway may help understand hedonistic overfeeding behavior observed due to modern AGE-rich diets.
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Affiliation(s)
| | | | | | | | - Sanjib Guha
- The Buck Institute for Research on AgingNovatoUnited States
| | - Manish Chamoli
- The Buck Institute for Research on AgingNovatoUnited States
| | - Brian Hodge
- The Buck Institute for Research on AgingNovatoUnited States
| | - Neelanjan Bose
- The Buck Institute for Research on AgingNovatoUnited States
| | - Charis Roberts
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - Dominique O Farrera
- Department of Pharmacology and Toxicology, College of Pharmacy, University of ArizonaTucsonUnited States
| | - Gordon Lithgow
- The Buck Institute for Research on AgingNovatoUnited States
| | - Richmond Sarpong
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - James J Galligan
- Department of Pharmacology and Toxicology, College of Pharmacy, University of ArizonaTucsonUnited States
| | - Pankaj Kapahi
- The Buck Institute for Research on AgingNovatoUnited States
- Department of Urology, University of California, San FranciscoSan FranciscoUnited States
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Palani SN, Sellegounder D, Wibisono P, Liu Y. The longevity response to warm temperature is neurally controlled via the regulation of collagen genes. Aging Cell 2023; 22:e13815. [PMID: 36895142 PMCID: PMC10186602 DOI: 10.1111/acel.13815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 03/11/2023] Open
Abstract
Studies in diverse species have associated higher temperatures with shorter lifespan and lower temperatures with longer lifespan. These inverse effects of temperature on longevity are traditionally explained using the rate of living theory, which posits that higher temperatures increase chemical reaction rates, thus speeding up the aging process. Recent studies have identified specific molecules and cells that affect the longevity response to temperature, indicating that this response is regulated, not simply thermodynamic. Here, we demonstrate that in Caenorhabditis elegans, functional loss of NPR-8, a G protein-coupled receptor related to mammalian neuropeptide Y receptors, increases worm lifespan at 25°C but not at 20°C or 15°C, and that the lifespan extension at 25°C is regulated by the NPR-8-expressing AWB and AWC chemosensory neurons as well as AFD thermosensory neurons. Integrative transcriptomic analyses revealed that both warm temperature and old age profoundly alter gene expression and that genes involved in the metabolic and biosynthetic processes increase expression at 25°C relative to 20°C, indicating elevated metabolism at warm temperature. These data demonstrate that the temperature-induced longevity response is neurally regulated and also provide a partial molecular basis for the rate of living theory, suggesting that these two views are not mutually exclusive. Genetic manipulation and functional assays further uncovered that the NPR-8-dependent longevity response to warm temperature is achieved by regulating the expression of a subset of collagen genes. As increased collagen expression is a common feature of many lifespan-extending interventions and enhanced stress resistance, collagen expression could be critical for healthy aging.
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Affiliation(s)
- Sankara Naynar Palani
- Department of Translational Medicine and Physiology, Elson S. Floyd College of MedicineWashington State UniversitySpokaneWashingtonUSA
| | - Durai Sellegounder
- Department of Translational Medicine and Physiology, Elson S. Floyd College of MedicineWashington State UniversitySpokaneWashingtonUSA
| | - Phillip Wibisono
- Department of Translational Medicine and Physiology, Elson S. Floyd College of MedicineWashington State UniversitySpokaneWashingtonUSA
| | - Yiyong Liu
- Department of Translational Medicine and Physiology, Elson S. Floyd College of MedicineWashington State UniversitySpokaneWashingtonUSA
- Genomics CoreWashington State UniversitySpokaneWashingtonUSA
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Sellegounder D, Ferrucci L, Anbazhagan R, Basisty N. Editorial: Molecular crosstalk between endocrine factors, paracrine signals, and the immune system during aging. Front Endocrinol (Lausanne) 2023; 14:1203755. [PMID: 37152922 PMCID: PMC10160671 DOI: 10.3389/fendo.2023.1203755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 04/14/2023] [Indexed: 05/09/2023] Open
Affiliation(s)
- Durai Sellegounder
- Buck Institute for Research on Aging, Novato, CA, United States
- *Correspondence: Durai Sellegounder,
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
| | - Rajakumar Anbazhagan
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Nathan Basisty
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States
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4
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Wibisono P, Wibisono S, Watteyne J, Chen CH, Sellegounder D, Beets I, Liu Y, Sun J. Neuronal GPCR NMUR-1 regulates distinct immune responses to different pathogens. Cell Rep 2022; 38:110321. [PMID: 35139379 PMCID: PMC8869846 DOI: 10.1016/j.celrep.2022.110321] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/21/2021] [Accepted: 01/10/2022] [Indexed: 12/29/2022] Open
Abstract
A key question in current immunology is how the innate immune system generates high levels of specificity. Using the Caenorhabditis elegans model system, we demonstrate that functional loss of NMUR-1, a neuronal G-protein-coupled receptor homologous to mammalian receptors for the neuropeptide neuromedin U, has diverse effects on C. elegans innate immunity against various bacterial pathogens. Transcriptomic analyses and functional assays reveal that NMUR-1 modulates C. elegans transcription activity by regulating the expression of transcription factors involved in binding to RNA polymerase II regulatory regions, which, in turn, controls the expression of distinct immune genes in response to different pathogens. These results uncover a molecular basis for the specificity of C. elegans innate immunity. Given the evolutionary conservation of NMUR-1 signaling in immune regulation across multicellular organisms, our study could provide mechanistic insights into understanding the specificity of innate immunity in other animals, including mammals.
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Affiliation(s)
- Phillip Wibisono
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Shawndra Wibisono
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Jan Watteyne
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Chia-Hui Chen
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Durai Sellegounder
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Isabel Beets
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Yiyong Liu
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA; Genomics Core, Washington State University, Spokane, WA, USA.
| | - Jingru Sun
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA.
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Sellegounder D, Zafari P, Rajabinejad M, Taghadosi M, Kapahi P. Advanced glycation end products (AGEs) and its receptor, RAGE, modulate age-dependent COVID-19 morbidity and mortality. A review and hypothesis. Int Immunopharmacol 2021; 98:107806. [PMID: 34352471 PMCID: PMC8141786 DOI: 10.1016/j.intimp.2021.107806] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/19/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
Coronavirus Disease 2019 (COVID-19), caused by the novel virus SARS-CoV-2, is often more severe in older adults. Besides age, other underlying conditions such as obesity, diabetes, high blood pressure, and malignancies, which are also associated with aging, have been considered risk factors for COVID-19 mortality. A rapidly expanding body of evidence has brought up various scenarios for these observations and hyperinflammatory reactions associated with COVID-19 pathogenesis. Advanced glycation end products (AGEs) generated upon glycation of proteins, DNA, or lipids play a crucial role in the pathogenesis of age-related diseases and all of the above-mentioned COVID-19 risk factors. Interestingly, the receptor for AGEs (RAGE) is mainly expressed by type 2 epithelial cells in the alveolar sac, which has a critical role in SARS-CoV-2-associated hyper inflammation and lung injury. Here we discuss our hypothesis that AGEs, through their interaction with RAGE amongst other molecules, modulates COVID-19 pathogenesis and related comorbidities, especially in the elderly.
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Affiliation(s)
- Durai Sellegounder
- (BuckInstitute for Researchon Aging), (Novato), (CA 94945), (United States)
| | - Parisa Zafari
- (Departmentof Immunology), (School of Medicine), (Mazandaran University of Medical Sciences), (Sari), (Iran)
| | - Misagh Rajabinejad
- (Departmentof Immunology), (School of Medicine), (Mazandaran University of Medical Sciences), (Sari), (Iran); (StudentResearch Committee), (Mazandaran University of Medical Sciences), (Iran)
| | - Mahdi Taghadosi
- (Departmentof Immunology), (School of Medicine), (Kermanshah University of Medical Sciences), (Kermanshah), (Iran).
| | - Pankaj Kapahi
- (BuckInstitute for Researchon Aging), (Novato), (CA 94945), (United States).
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Khanna A, Sellegounder D, Kumar J, Chamoli M, Vargas M, Chinta SJ, Rane A, Nelson C, Peiris TH, Brem R, Andersen J, Lithgow G, Kapahi P. Trimethylamine modulates dauer formation, neurodegeneration, and lifespan through tyra-3/daf-11 signaling in Caenorhabditis elegans. Aging Cell 2021; 20:e13351. [PMID: 33819374 PMCID: PMC8135002 DOI: 10.1111/acel.13351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 11/27/2022] Open
Abstract
In the nematode Caenorhabditis elegans, signals derived from bacteria in the diet, the animal's major nutrient source, can modulate both behavior and healthspan. Here we describe a dual role for trimethylamine (TMA), a human gut flora metabolite, which acts as a nutrient signal and a neurotoxin. TMA and its associated metabolites are produced by the human gut microbiome and have been suggested to serve as risk biomarkers for diabetes and cardiovascular diseases. We demonstrate that the tyramine receptor TYRA-3, a conserved G protein-coupled receptor (GPCR), is required to sense TMA and mediate its responses. TMA activates guanylyl cyclase DAF-11 signaling through TYRA-3 in amphid neurons (ASK) and ciliated neurons (BAG) to mediate food-sensing behavior. Bacterial mutants deficient in TMA production enhance dauer formation, extend lifespan, and are less preferred as a food source. Increased levels of TMA lead to neural damage in models of Parkinson's disease and shorten lifespan. Our results reveal conserved signaling pathways modulated by TMA in C. elegans that are likely to be relevant for its effects in mammalian systems.
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Affiliation(s)
- Amit Khanna
- Buck Institute for Research on Aging Novato CA USA
- Dovetail Genomics LLC Scotts Valley CA USA
| | | | | | | | | | - Shankar J. Chinta
- Buck Institute for Research on Aging Novato CA USA
- Touro University California Vallejo CA USA
| | - Anand Rane
- Buck Institute for Research on Aging Novato CA USA
| | | | | | - Rachel Brem
- Buck Institute for Research on Aging Novato CA USA
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Sellegounder D, Liu Y, Wibisono P, Chen CH, Leap D, Sun J. Neuronal GPCR NPR-8 regulates C. elegans defense against pathogen infection. Sci Adv 2019; 5:eaaw4717. [PMID: 31799388 PMCID: PMC6867885 DOI: 10.1126/sciadv.aaw4717] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 09/17/2019] [Indexed: 05/18/2023]
Abstract
Increasing evidence indicates that infection-triggered host defenses are regulated by the nervous system. However, the precise mechanisms of this regulation are not well understood. Here, we demonstrate that neuronal G protein-coupled receptor NPR-8 negatively regulates Caenorhabditis elegans defense against pathogen infection by suppressing cuticular collagen expression. NPR-8 controls the dynamics of cuticle structure in response to infection, likely through its regulation of cuticular collagen genes which, in turn, affects the nematode's defense. We further show that the defense activity of NPR-8 is confined to amphid sensory neurons AWB, ASJ, and AWC. It is generally believed that physical barrier defenses are not a response to infections but are part of the body's basic innate defense against pathogens. Our results challenge this view by showing not only that C. elegans cuticle structure dynamically changes in response to infection but also that the cuticle barrier defense is regulated by the nervous system.
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Affiliation(s)
- Durai Sellegounder
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Yiyong Liu
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
- Genomics Core, Washington State University, Spokane, WA, USA
| | - Phillip Wibisono
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Chia-Hui Chen
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - David Leap
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Jingru Sun
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
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8
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Sellegounder D, Gupta YR, Murugananthkumar R, Senthilkumaran B. Enterotoxic effects of Aeromonas hydrophila infection in the catfish, Clarias gariepinus: Biochemical, histological and proteome analyses. Vet Immunol Immunopathol 2018; 204:1-10. [PMID: 30596375 DOI: 10.1016/j.vetimm.2018.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 08/19/2018] [Accepted: 08/20/2018] [Indexed: 12/26/2022]
Abstract
Aeromonas hydrophila is considered as a potential risk to fish populations in the aquaculture industry and could also pose a serious threat to humans. In this study, the impact of A. hydrophila infection in the air-breathing catfish, Clarias gariepinus was analyzed using a multidimensional approach. Aeromonas hydrophila (1 × 107 cells) was injected into C. gariepinus intraperitoneally and maintained at an ambient temperature and photoperiod with periodical monitoring for morphological changes. After 7 days post-infection, tissue samples of the gills, liver, intestine, and kidney were subjected to biochemical, histological, transmission electron microscope (TEM) and proteomic analyses. Observed results indicated distinct morphological changes with the significant increase of ROS and oxidative stress enzymes (CAT and SOD) in tissues of the infected group when compared to the control. Histological analysis in infected fish revealed the presence of pyknotic nuclei, early stages of necrosis in the liver, degradation of renal tubules and widened sinusoidal space in kidneys along with enlargement of the epithelial region in the intestine. TEM analysis of the infected intestine showed degeneration of villi and the presence of multinucleated erythrocytes. Two-dimensional proteomic and mass spectrometry analysis of intestine and liver displayed up-regulation of several immune regulatory proteins such as proteasome subunit 3 protein, prolactin and intermediated filament protein; and down-regulation of proteins including actin, serine/arginine-rich splicing factor and carbonic anhydrase. Taken together, these results suggest that the identified proteins may have a role in immune regulation against A. hydrophila infection in C. gariepinus and support further investigations of host-pathogen interactions.
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Affiliation(s)
- Durai Sellegounder
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, India
| | - Yugantak Raj Gupta
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, India
| | - Raju Murugananthkumar
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, India
| | - Balasubramanian Senthilkumaran
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, India.
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Gupta YR, Sellegounder D, Kannan M, Deepa S, Senthilkumaran B, Basavaraju Y. Effect of copper nanoparticles exposure in the physiology of the common carp ( Cyprinus carpio ): Biochemical, histological and proteomic approaches. Aquaculture and Fisheries 2016. [DOI: 10.1016/j.aaf.2016.09.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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10
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Liu Y, Sellegounder D, Sun J. Neuronal GPCR OCTR-1 regulates innate immunity by controlling protein synthesis in Caenorhabditis elegans. Sci Rep 2016; 6:36832. [PMID: 27833098 PMCID: PMC5104976 DOI: 10.1038/srep36832] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 10/18/2016] [Indexed: 01/09/2023] Open
Abstract
Upon pathogen infection, microbial killing pathways and cellular stress pathways are rapidly activated by the host innate immune system. These pathways must be tightly regulated because insufficient or excessive immune responses have deleterious consequences. Increasing evidence indicates that the nervous system regulates the immune system to confer coordinated protection to the host. However, the precise mechanisms of neural-immune communication remain unclear. Previously we have demonstrated that OCTR-1, a neuronal G protein-coupled receptor, functions in the sensory neurons ASH and ASI to suppress innate immune responses in non-neural tissues against Pseudomonas aeruginosa in Caenorhabditis elegans. In the current study, by using a mass spectrometry-based quantitative proteomics approach, we discovered that OCTR-1 regulates innate immunity by suppressing translation and the unfolded protein response (UPR) pathways at the protein level. Functional assays revealed that OCTR-1 inhibits specific protein synthesis factors such as ribosomal protein RPS-1 and translation initiation factor EIF-3.J to reduce infection-triggered protein synthesis and UPR. Translational inhibition by chemicals abolishes the OCTR-1-controlled innate immune responses, indicating that activation of the OCTR-1 pathway is dependent on translation upregulation such as that induced by pathogen infection. Because OCTR-1 downregulates protein translation activities, the OCTR-1 pathway could function to suppress excessive responses to infection or to restore protein homeostasis after infection.
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Affiliation(s)
- Yiyong Liu
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| | - Durai Sellegounder
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| | - Jingru Sun
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
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Balasubramanian V, Sellegounder D, Suman K, Krishnaswamy B. Proteome analysis reveals translational inhibition of Caenorhabditis elegans enhances susceptibility to Pseudomonas aeruginosa PAO1 pathogenesis. J Proteomics 2016; 145:141-152. [PMID: 27109352 DOI: 10.1016/j.jprot.2016.04.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 04/12/2016] [Accepted: 04/17/2016] [Indexed: 01/14/2023]
Abstract
UNLABELLED Caenorhabditis elegans-Pseudomonas aeruginosa infection model is commonly used for pathogenesis studies over the decades. In the present study, upon exposure to the Pseudomonas aeruginosa PAO1, the 2D-PAGE was performed to examine the total proteins differences of C. elegans during the PAO1 infection at different time durations (12-48h). Also, the 2D-DIGE using the cyanine dyes were performed (48h) to identify the differentially regulated proteins against the PAO1 infection. Among the 19 short-listed proteins, 5 proteins were down-regulated and 14 proteins were up-regulated. Eukaryotic elongation factor-2 (EEF-2), a GTP binding protein involves in protein elongation process was down regulated during the pathogen infection. The 2D-PAGE analysis and MS data for the 12 and 24h infections identified the NDK-1 and other essential protein includes, ACS-18, ACT-1, GPD-3, GDH-1 and LBP-6 which are involved in important cellular homeostasis were down regulated. Validation studies using qPCR analysis for eef-2 and other selected genes, western blot analysis for EEF-2 and effect of host translational inhibition studies using Cycloheximide during PAO1 infection suggests that P. aeruginosa systematically restrains the function of host by arresting the expression of EEF-2 and thereby inhibiting protein translational events. Further, in silico analysis revealed the Exotoxin A could directly bind with the host EEF-2 and NDK-1 during the C. elegans- PAO1 interactions. BIOLOGICAL SIGNIFICANCE Model system, C. elegans facilitates the identification of virulence mechanisms during bacterial pathogenesis. Upon infection by the fungal and bacterial pathogens, the C. elegans system induces an array of transcriptional responses, including differential expression of effector/modulator genes that provide safeguard and fight against infection. However, the in-depth knowledge of host response by the pathogen at protein level remains unclear. Much of the studies were carried out only at the transcripts level and scarce reports are available at the protein level for the host-pathogen interaction studies. In order to provide few interesting clues at the protein level, the nematode, C. elegans was infected with the human pathogen P. aeruginosa and the response(s) of host was investigated at the protein level by 2D-DIGE analysis and further validation studies using qPCR and western blotting techniques. Our differential proteomics data suggest that translational inhibition as one of the patterns of pathogenesis in C. elegans during P. aeruginosa infection. Since many of the effectors identified through C. elegans are conserved in other systems including human, our data pave the way for understanding important regulatory pathways involved during bacterial pathogenesis that can be translated into higher eukaryotic organisms.
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Affiliation(s)
| | - Durai Sellegounder
- Department of Biotechnology, Science Campus, Alagappa University, Karaikudi, India
| | - Kundu Suman
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
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