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Yanagi KS, Jochim B, Kunjo SO, Breen P, Ruvkun G, Lehrbach N. Mutations in nucleotide metabolism genes bypass proteasome defects in png-1/NGLY1-deficient Caenorhabditis elegans. PLoS Biol 2024; 22:e3002720. [PMID: 38991033 PMCID: PMC11265709 DOI: 10.1371/journal.pbio.3002720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 07/23/2024] [Accepted: 06/21/2024] [Indexed: 07/13/2024] Open
Abstract
The conserved SKN-1A/Nrf1 transcription factor regulates the expression of proteasome subunit genes and is essential for maintenance of adequate proteasome function in animal development, aging, and stress responses. Unusual among transcription factors, SKN-1A/Nrf1 is a glycoprotein synthesized in the endoplasmic reticulum (ER). N-glycosylated SKN-1A/Nrf1 exits the ER and is deglycosylated in the cytosol by the PNG-1/NGLY1 peptide:N-glycanase. Deglycosylation edits the protein sequence of SKN-1A/Nrf1 by converting N-glycosylated asparagine residues to aspartate, which is necessary for SKN-1A/Nrf1 transcriptional activation of proteasome subunit genes. Homozygous loss-of-function mutations in the peptide:N-glycanase (NGLY1) gene cause NGLY1 deficiency, a congenital disorder of deglycosylation. There are no effective treatments for NGLY1 deficiency. Since SKN-1A/Nrf1 is a major client of NGLY1, the resulting proteasome deficit contributes to NGLY1 disease. We sought to identify targets for mitigation of proteasome dysfunction in NGLY1 deficiency that might indicate new avenues for treatment. We isolated mutations that suppress the sensitivity to proteasome inhibitors caused by inactivation of the NGLY1 ortholog PNG-1 in Caenorhabditis elegans. We identified multiple suppressor mutations affecting 3 conserved genes: rsks-1, tald-1, and ent-4. We show that the suppressors act through a SKN-1/Nrf-independent mechanism and confer proteostasis benefits consistent with amelioration of proteasome dysfunction. ent-4 encodes an intestinal nucleoside/nucleotide transporter, and we show that restriction of nucleotide availability is beneficial, whereas a nucleotide-rich diet exacerbates proteasome dysfunction in PNG-1/NGLY1-deficient C. elegans. Our findings suggest that dietary or pharmacological interventions altering nucleotide availability have the potential to mitigate proteasome insufficiency in NGLY1 deficiency and other diseases associated with proteasome dysfunction.
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Affiliation(s)
- Katherine S. Yanagi
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Briar Jochim
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Sheikh Omar Kunjo
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Peter Breen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nicolas Lehrbach
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
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2
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Torzone SK, Breen PC, Cohen NR, Simmons KN, Dowen RH. The TWK-26 potassium channel governs nutrient absorption in the C. elegans intestine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.06.592787. [PMID: 38766028 PMCID: PMC11100751 DOI: 10.1101/2024.05.06.592787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Ion channels are necessary for proper water and nutrient absorption in the intestine, which supports cellular metabolism and organismal growth. While a role for Na + co-transporters and pumps in intestinal nutrient absorption is well defined, how individual K + uniporters function to maintain ion homeostasis is poorly understood. Using Caenorhabditis elegans , we show that a gain-of-function mutation in twk-26 , which encodes a two-pore domain K + ion channel orthologous to human KCNK3, facilitates nutrient absorption and suppresses the metabolic and developmental defects displayed by impaired intestinal MAP Kinase (MAPK) signaling. Mutations in drl-1 and flr-4, which encode two components of this MAPK pathway, cause severe growth defects, reduced lipid storage, and a dramatic increase in autophagic lysosomes, which mirror dietary restriction phenotypes. Additionally, these MAPK mutants display structural defects of the intestine and an impaired defecation motor program. We find that activation of TWK-26 reverses the dietary restriction-like state of the MAPK mutants by restoring intestinal nutrient absorption without correcting the intestinal bloating or defecation defects. This study provides unique insight into the mechanisms by which intestinal K + ion channels support intestinal metabolic homeostasis.
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Schifano E, Conta G, Preziosi A, Ferrante C, Batignani G, Mancini P, Tomassini A, Sciubba F, Scopigno T, Uccelletti D, Miccheli A. 2-hydroxyisobutyric acid (2-HIBA) modulates ageing and fat deposition in Caenorhabditis elegans. Front Mol Biosci 2022; 9:986022. [PMID: 36533081 PMCID: PMC9749906 DOI: 10.3389/fmolb.2022.986022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 11/07/2022] [Indexed: 06/30/2024] Open
Abstract
High levels of 2-hydroxyisobutyric acid (2-HIBA) were found in urines of patients with obesity and hepatic steatosis, suggesting a potential involvement of this metabolite in clinical conditions. The gut microbial origin of 2-HIBA was hypothesized, however its actual origin and role in biological processes are still not clear. We investigated how treatment with 2-HIBA affected the physiology of the model organism Caenorhabditis elegans, in both standard and high-glucose diet (HGD) growth conditions, by targeted transcriptomic and metabolomic analyses, Coherent Anti-Stokes Raman Scattering (CARS) and two-photon fluorescence microscopy. In standard conditions, 2-HIBA resulted particularly effective to extend the lifespan, delay ageing processes and stimulate the oxidative stress resistance in wild type nematodes through the activation of insulin/IGF-1 signaling (IIS) and p38 MAPK pathways and, consequently, through a reduction of ROS levels. Moreover, variations of lipid accumulation observed in treated worms correlated with transcriptional levels of fatty acid synthesis genes and with the involvement of peptide transporter PEP-2. In HGD conditions, the effect of 2-HIBA on C. elegans resulted in a reduction of the lipid droplets deposition, accordingly with an increase of acs-2 gene transcription, involved in β-oxidation processes. In addition, the pro-longevity effect appeared to be correlated to higher levels of tryptophan, which may play a role in restoring the decreased viability observed in the HGD untreated nematodes.
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Affiliation(s)
- Emily Schifano
- Department of Biology and Biotechnology “C. Darwin”, Sapienza University of Rome, Rome, Italy
| | - Giorgia Conta
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
- NMR-based Metabolomics Laboratory of Sapienza (NMLab), Sapienza University of Rome, Rome, Italy
| | - Adele Preziosi
- Department of Biology and Biotechnology “C. Darwin”, Sapienza University of Rome, Rome, Italy
| | - Carino Ferrante
- Department of Physics, Sapienza University of Rome, Rome, Italy
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Giovanni Batignani
- Department of Physics, Sapienza University of Rome, Rome, Italy
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Patrizia Mancini
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Alberta Tomassini
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
- NMR-based Metabolomics Laboratory of Sapienza (NMLab), Sapienza University of Rome, Rome, Italy
| | - Fabio Sciubba
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
- NMR-based Metabolomics Laboratory of Sapienza (NMLab), Sapienza University of Rome, Rome, Italy
| | - Tullio Scopigno
- Department of Physics, Sapienza University of Rome, Rome, Italy
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Daniela Uccelletti
- Department of Biology and Biotechnology “C. Darwin”, Sapienza University of Rome, Rome, Italy
| | - Alfredo Miccheli
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
- NMR-based Metabolomics Laboratory of Sapienza (NMLab), Sapienza University of Rome, Rome, Italy
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4
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Wu Y, Yang J, Xu C, Li Q, Ma Y, Zhao S, Zhuang J, Shen F, Wang Q, Feng F, Zhang X. Sea cucumber ( Acaudina leucoprocta) peptides extended the lifespan and enhanced antioxidant capacity via DAF-16/DAF-2/SOD-3/OLD-1/PEPT-1 in Caenorhabditis elegans. Front Nutr 2022; 9:1065145. [PMID: 36483922 PMCID: PMC9723373 DOI: 10.3389/fnut.2022.1065145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 11/01/2022] [Indexed: 09/29/2023] Open
Abstract
The sea cucumber peptides (SCPs) from Acaudina leucoprocta were derived from the patented bio-enzyme digestion technology and the molecular weight of obtained SCPs was < 10 kDa. In this study, we investigated the possible anti-aging effects of SCPs on the model of Caenorhabditis elegans and the underlying mechanisms. SCPs extend the average lifespan of nematodes by 31.46%. SCPs enhance the anti-stress capacity of C. elegans by improving heat resistance and mobility, Also, the accumulated potential oxidative stress inducers like lipofuscin and reactive oxygen species (ROS) were reduced to 40.84 and 71.43%. In addition, SCPs can increase the antioxidant capacity in nematodes by enhancing the activity of SOD and CAT and reducing MDA accumulation in nematodes to 32.44%. Mechanistically, SCPs could mediate DAF-16/DAF-2/SOD-3/OLD-1/PEPT-1 axis to improve antioxidant capacity and extend lifespan in nematodes. Taken together, these findings provide a direction for the anti-aging effects of sea cucumber peptides and new insights into the further purifications of SCPs and future research on aging.
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Affiliation(s)
- Yue Wu
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
| | - Jingjuan Yang
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
| | - Chengmei Xu
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
| | - Qiuqi Li
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
| | - Yage Ma
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
| | - Shenglan Zhao
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
| | - Jiachen Zhuang
- School of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Fei Shen
- School of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Qianqian Wang
- School of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Fengqin Feng
- School of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Xi Zhang
- School of Traditional Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, China
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5
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Khavinson V, Linkova N, Kozhevnikova E, Dyatlova A, Petukhov M. Transport of Biologically Active Ultrashort Peptides Using POT and LAT Carriers. Int J Mol Sci 2022; 23:ijms23147733. [PMID: 35887081 PMCID: PMC9323678 DOI: 10.3390/ijms23147733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023] Open
Abstract
Ultrashort peptides (USPs), consisting of 2–7 amino-acid residues, are a group of signaling molecules that regulate gene expression and protein synthesis under normal conditions in various diseases and ageing. USPs serve as a basis for the development of drugs with a targeted mechanism of action. The purpose of this review is to systematize the available data on USP transport involving POT and LAT transporters in various organs and tissues under normal, pathological and ageing conditions. The carriers of the POT family (PEPT1, PEPT2, PHT1, PHT2) transport predominantly di- and tripeptides into the cell. Methods of molecular modeling and physicochemistry have demonstrated the ability of LAT1 to transfer not only amino acids but also some di- and tripeptides into the cell and out of it. LAT1 and 2 are involved in the regulation of the antioxidant, endocrine, immune and nervous systems’ functions. Analysis of the above data allows us to conclude that, depending on their structure, di- and tripeptides can be transported into the cells of various tissues by POT and LAT transporters. This mechanism is likely to underlie the tissue specificity of peptides, their geroprotective action and effectiveness in the case of neuroimmunoendocrine system disorders.
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Affiliation(s)
- Vladimir Khavinson
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
- Group of Peptide Regulation of Aging, Pavlov Institute of Physiology of Russian Academy of Sciences, 199034 Saint Petersburg, Russia
- Correspondence: or ; Tel.: +7-(921)-9110800
| | - Natalia Linkova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
- The Laboratory “Problems of Aging”, Belgorod National Research University, 308015 Belgorod, Russia
| | - Ekaterina Kozhevnikova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
| | - Anastasiia Dyatlova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
| | - Mikhael Petukhov
- Petersburg Nuclear Physics Institute Named after B.P. Konstantinov, NRC “Kurchatov Institute”, 188300 Gatchina, Russia;
- Peter the Great St. Petersburg Group of Biophysics, Higher Engineering and Technical School, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
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6
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Zhu M, Teng F, Li N, Zhang L, Zhang S, Xu F, Shao J, Sun H, Zhu H. Monomethyl branched-chain fatty acid mediates amino acid sensing upstream of mTORC1. Dev Cell 2021; 56:2692-2702.e5. [PMID: 34610328 DOI: 10.1016/j.devcel.2021.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/24/2021] [Accepted: 09/10/2021] [Indexed: 10/20/2022]
Abstract
Animals have developed various nutrient-sensing mechanisms for survival under fluctuating environmental conditions. Although extensive cell-culture-based analyses have identified diverse mediators of amino acid sensing upstream of mTOR, studies using animal models to examine intestine-initiated amino acid sensing mechanisms under specific physiological conditions are lacking. Here, we developed a Caenorhabditis elegans model to examine the impact of amino acid deficiency on development. We discovered a leucine-derived monomethyl branched-chain fatty acid and its downstream metabolite, glycosphingolipid, which critically mediates the overall amino acid sensing by intestinal and neuronal mTORC1, which in turn regulates postembryonic development at least partly by controlling protein translation and ribosomal biogenesis. Additional data suggest that a similar mechanism may operate in mammals. This study uncovers an amino-acid-sensing mechanism mediated by a lipid biosynthesis pathway.
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Affiliation(s)
- Mengnan Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fukang Teng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Na Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Li Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shuxian Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Fan Xu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jing Shao
- National Humanities Center Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Center for Cardiovascular Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Haipeng Sun
- National Humanities Center Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Center for Cardiovascular Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Huanhu Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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7
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Meirelles MG, Nornberg BF, da Silveira TLR, Kütter MT, Castro CG, Ramirez JRB, Pedrosa V, Romano LA, Marins LF. Growth Hormone Overexpression Induces Hyperphagia and Intestinal Morphophysiological Adaptations to Improve Nutrient Uptake in Zebrafish. Front Physiol 2021; 12:723853. [PMID: 34539447 PMCID: PMC8442846 DOI: 10.3389/fphys.2021.723853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/04/2021] [Indexed: 11/30/2022] Open
Abstract
The excess of circulating growth hormone (GH) in most transgenic animals implies mandatory growth resulting in higher metabolic demand. Considering that the intestine is the main organ responsible for the digestion, absorption, and direction of dietary nutrients to other tissues, this study aimed to investigate the mechanisms by which gh overexpression modulates the intestine to support higher growth. For this purpose, we designed an 8-weeks feeding trial to evaluate growth parameters, feed intake, and intestinal morphometric indices in the adult gh-transgenic zebrafish (Danio rerio) model. To access the sensitivity of the intestine to the excess of circulating GH, the messenger RNA (mRNA) expression of intestine GH receptors (GHRs) (ghra and ghrb) was analyzed. In addition, the expression of insulin-like growth factor 1a (igf1a) and genes encoding for di and tripeptide transporters (pept1a and pept1b) were assessed. Gh-transgenic zebrafish had better growth performance and higher feed intake compared to non-transgenic sibling controls. Chronic excess of GH upregulates the expression of its cognate receptor (ghrb) and the main growth factor related to trophic effects in the intestine (igf1a). Moreover, transgenic zebrafish showed an increased intestinal absorptive area and higher expression of crucial genes related to the absorption of products from meal protein degradation. These results reinforce the ability of GH to modulate intestinal morphology and the mechanisms of assimilation of nutrients to sustain the energy demand for the continuous growth induced by the excess of circulating GH.
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Affiliation(s)
- Marcela G Meirelles
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Bruna F Nornberg
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Tony L R da Silveira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Mateus T Kütter
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Caroline G Castro
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Juan Rafael B Ramirez
- Laboratório de Bioquímica Funcional de Organismos Aquáticos, Instituto de Oceanografia, Estação Marinha de Aquicultura, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Virgínia Pedrosa
- Laboratório de Imunologia e Patologia de Organismos Aquáticos, Instituto de Oceanografia, Estação Marinha de Aquicultura, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Luis Alberto Romano
- Laboratório de Imunologia e Patologia de Organismos Aquáticos, Instituto de Oceanografia, Estação Marinha de Aquicultura, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
| | - Luis Fernando Marins
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil
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8
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Cooper JF, Guasp RJ, Arnold ML, Grant BD, Driscoll M. Stress increases in exopher-mediated neuronal extrusion require lipid biosynthesis, FGF, and EGF RAS/MAPK signaling. Proc Natl Acad Sci U S A 2021; 118:e2101410118. [PMID: 34475208 PMCID: PMC8433523 DOI: 10.1073/pnas.2101410118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 06/23/2021] [Indexed: 01/08/2023] Open
Abstract
In human neurodegenerative diseases, neurons can transfer toxic protein aggregates to surrounding cells, promoting pathology via poorly understood mechanisms. In Caenorhabditis elegans, proteostressed neurons can expel neurotoxic proteins in large, membrane-bound vesicles called exophers. We investigated how specific stresses impact neuronal trash expulsion to show that neuronal exopher production can be markedly elevated by oxidative and osmotic stress. Unexpectedly, we also found that fasting dramatically increases exophergenesis. Mechanistic dissection focused on identifying nonautonomous factors that sense and activate the fasting-induced exopher response revealed that DAF16/FOXO-dependent and -independent processes are engaged. Fasting-induced exopher elevation requires the intestinal peptide transporter PEPT-1, lipid synthesis transcription factors Mediator complex MDT-15 and SBP-1/SREPB1, and fatty acid synthase FASN-1, implicating remotely initiated lipid signaling in neuronal trash elimination. A conserved fibroblast growth factor (FGF)/RAS/MAPK signaling pathway that acts downstream of, or in parallel to, lipid signaling also promotes fasting-induced neuronal exopher elevation. A germline-based epidermal growth factor (EGF) signal that acts through neurons is also required for exopher production. Our data define a nonautonomous network that links food availability changes to remote, and extreme, neuronal homeostasis responses relevant to aggregate transfer biology.
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Affiliation(s)
- Jason F Cooper
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
| | - Ryan J Guasp
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
| | - Meghan Lee Arnold
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
| | - Barth D Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
- Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854;
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9
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Yan J, Sun CL, Shin S, Van Gilst M, Crowder CM. Effect of the mitochondrial unfolded protein response on hypoxic death and mitochondrial protein aggregation. Cell Death Dis 2021; 12:711. [PMID: 34267182 PMCID: PMC8282665 DOI: 10.1038/s41419-021-03979-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/23/2022]
Abstract
Mitochondria are the main oxygen consumers in cells and as such are the primary organelle affected by hypoxia. All hypoxia pathology presumably derives from the initial mitochondrial dysfunction. An early event in hypoxic pathology in C. elegans is disruption of mitochondrial proteostasis with induction of the mitochondrial unfolded protein response (UPRmt) and mitochondrial protein aggregation. Here in C. elegans, we screen through RNAis and mutants that confer either strong resistance to hypoxic cell death or strong induction of the UPRmt to determine the relationship between hypoxic cell death, UPRmt activation, and hypoxia-induced mitochondrial protein aggregation (HIMPA). We find that resistance to hypoxic cell death invariantly mitigated HIMPA. We also find that UPRmt activation invariantly mitigated HIMPA. However, UPRmt activation was neither necessary nor sufficient for resistance to hypoxic death and vice versa. We conclude that UPRmt is not necessarily hypoxia protective against cell death but does protect from mitochondrial protein aggregation, one of the early hypoxic pathologies in C. elegans.
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Affiliation(s)
- Junyi Yan
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, 98109, USA.,Mitochondrial and Metabolism Center, University of Washington School of Medicine, Seattle, WA, 98109, USA.,Department of Anesthesiology, Central Hospital of Changdian, 118214, Dandong, Liaoning, China
| | - Chun-Ling Sun
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, 98109, USA.,Mitochondrial and Metabolism Center, University of Washington School of Medicine, Seattle, WA, 98109, USA
| | - Seokyung Shin
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, 98109, USA.,Mitochondrial and Metabolism Center, University of Washington School of Medicine, Seattle, WA, 98109, USA.,Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Marc Van Gilst
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, 98109, USA.,Mitochondrial and Metabolism Center, University of Washington School of Medicine, Seattle, WA, 98109, USA
| | - C Michael Crowder
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, 98109, USA. .,Mitochondrial and Metabolism Center, University of Washington School of Medicine, Seattle, WA, 98109, USA. .,Department of Genome Science, University of Washington School of Medicine, Seattle, WA, 98109, USA.
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10
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Naim N, Amrit FRG, Ratnappan R, DelBuono N, Loose JA, Ghazi A. Cell nonautonomous roles of NHR-49 in promoting longevity and innate immunity. Aging Cell 2021; 20:e13413. [PMID: 34156142 PMCID: PMC8282243 DOI: 10.1111/acel.13413] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 05/06/2021] [Accepted: 05/14/2021] [Indexed: 02/06/2023] Open
Abstract
Aging and immunity are inextricably linked and many genes that extend life span also enhance immunoresistance. However, it remains unclear whether longevity-enhancing factors modulate immunity and longevity by discrete or shared mechanisms. Here, we demonstrate that the Caenorhabditis elegans pro-longevity factor, NHR-49, also promotes resistance against Pseudomonas aeruginosa but modulates immunity and longevity distinctly. NHR-49 expression increases upon germline ablation, an intervention that extends life span, but was lowered by Pseudomonas infection. The immunosusceptibility induced by nhr-49 loss of function was rescued by neuronal NHR-49 alone, whereas the longevity diminution was rescued by expression in multiple somatic tissues. The well-established NHR-49 target genes, acs-2 and fmo-2, were also differentially regulated following germline elimination or Pseudomonas exposure. Interestingly, neither gene conferred immunity toward Gram-negative Pseudomonas, unlike their known functions against gram-positive pathogens. Instead, genes encoding antimicrobial factors and xenobiotic-response proteins upregulated by NHR-49 contributed to resistance against Pseudomonas. Thus, NHR-49 is differentially regulated by interventions that bring about long-term changes (life span extension) versus short-term stress (pathogen exposure) and in response it orchestrates discrete outputs, including pathogen-specific transcriptional programs.
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Affiliation(s)
- Nikki Naim
- Department of Pediatrics University of Pittsburgh School of Medicine Pittsburgh PA USA
| | - Francis R. G. Amrit
- Department of Pediatrics University of Pittsburgh School of Medicine Pittsburgh PA USA
| | - Ramesh Ratnappan
- Department of Pediatrics University of Pittsburgh School of Medicine Pittsburgh PA USA
| | - Nicholas DelBuono
- Department of Pediatrics University of Pittsburgh School of Medicine Pittsburgh PA USA
| | - Julia A. Loose
- Department of Pediatrics University of Pittsburgh School of Medicine Pittsburgh PA USA
| | - Arjumand Ghazi
- Department of Pediatrics University of Pittsburgh School of Medicine Pittsburgh PA USA
- Departments of Developmental Biology and Cell Biology and Physiology University of Pittsburgh School of Medicine Pittsburgh PA USA
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11
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Jasmer DP, Rosa BA, Mitreva M. Cell Death and Transcriptional Responses Induced in Larvae of the Nematode Haemonchus contortus by Toxins/Toxicants with Broad Phylogenetic Efficacy. Pharmaceuticals (Basel) 2021; 14:598. [PMID: 34206464 PMCID: PMC8308827 DOI: 10.3390/ph14070598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/18/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
Establishing methods to investigate treatments that induce cell death in parasitic nematodes will promote experimental approaches to elucidate mechanisms and to identify prospective anthelmintics capable of inducing this outcome. Here, we extended recent progress on a method to monitor cell death and to identify small molecule inhibitors in Ascaris suum to Haemonchus contortus, a phylogenetically distant parasitic nematode of significance for both human and agricultural animal health. We utilized a diverse group of small molecule inhibitors referred to as nematode intestinal toxins/toxicants (NITs) coupled with motility, cytological and cell death assays to resolve gross effects on motility and individual cells and organ systems of two H. contortus larval stages in culture. Early transcriptional response evaluation identified NIT-responsive genes and pathways. The scope of death among cells in larvae varied among NITs but shared patterns with A. suum, despite the approach having some limitations due to characteristics of H. contortus larvae. Gene response patterns varied among NITs tested and provided information on the cell targets and pathways affected. Experimental NIT assays provide tools capable of inducing cell death in larval stages of parasitic nematodes, and can resolve many individual cells and organ systems in which cell death can be induced.
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Affiliation(s)
- Douglas P. Jasmer
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA;
| | - Bruce A. Rosa
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA;
| | - Makedonka Mitreva
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA;
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63108, USA
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12
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Mirisola MG. Diet and Calorie Restriction. ENCYCLOPEDIA OF GERONTOLOGY AND POPULATION AGING 2021:1425-1434. [DOI: 10.1007/978-3-030-22009-9_123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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13
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Itani OA, Zhong X, Tang X, Scott BA, Yan JY, Flibotte S, Lim Y, Hsieh AC, Bruce JE, Van Gilst M, Crowder CM. Coordinate Regulation of Ribosome and tRNA Biogenesis Controls Hypoxic Injury and Translation. Curr Biol 2020; 31:128-137.e5. [PMID: 33157031 DOI: 10.1016/j.cub.2020.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/21/2020] [Accepted: 10/01/2020] [Indexed: 01/01/2023]
Abstract
The translation machinery is composed of a myriad of proteins and RNAs whose levels must be coordinated to efficiently produce proteins without wasting energy or substrate. However, protein synthesis is clearly not always perfectly tuned to its environment, as disruption of translation machinery components can lengthen lifespan and stress survival. While much has been learned from bacteria and yeast about translational regulation, much less is known in metazoans. In a screen for mutations protecting C. elegans from hypoxic stress, we isolated multiple genes impacting protein synthesis: a ribosomal RNA helicase gene, tRNA biosynthesis genes, and a gene controlling amino acid availability. To define better the mechanisms by which these genes impact protein synthesis, we performed a second screen for suppressors of the conditional developmental arrest phenotype of the RNA helicase mutant and identified genes involved in ribosome biogenesis. Surprisingly, these suppressor mutations restored normal hypoxic sensitivity and protein synthesis to the tRNA biogenesis mutants, but not to the mutant reducing amino acid uptake. Proteomic analysis demonstrated that reduced tRNA biosynthetic activity produces a selective homeostatic reduction in ribosomal subunits, thereby offering a mechanism for the suppression results. Our study uncovers an unrecognized higher-order-translation regulatory mechanism in a metazoan whereby ribosome biogenesis genes communicate with genes controlling tRNA abundance matching the global rate of protein synthesis with available resources.
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Affiliation(s)
- Omar A Itani
- Department of Anesthesiology and Pain Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-6540, USA; Mitochondria and Metabolism Center, University of Washington, 850 Republican Street, Seattle, WA 98105, USA
| | - Xuefei Zhong
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Xiaoting Tang
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Barbara A Scott
- Department of Anesthesiology and Pain Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-6540, USA; Mitochondria and Metabolism Center, University of Washington, 850 Republican Street, Seattle, WA 98105, USA
| | - Jun Yi Yan
- Department of Anesthesiology and Pain Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-6540, USA; Mitochondria and Metabolism Center, University of Washington, 850 Republican Street, Seattle, WA 98105, USA; Department of Anesthesiology, Central Hospital of Changdian, Dandong, Liaoning 118214, China
| | - Stephane Flibotte
- Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall Vancouver, BC V6T 1Z3, Canada
| | - Yiting Lim
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109, USA
| | - Andrew C Hsieh
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA; Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109, USA; Department of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-6420, USA
| | - James E Bruce
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Marc Van Gilst
- Department of Anesthesiology and Pain Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-6540, USA; Mitochondria and Metabolism Center, University of Washington, 850 Republican Street, Seattle, WA 98105, USA
| | - C Michael Crowder
- Department of Anesthesiology and Pain Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-6540, USA; Mitochondria and Metabolism Center, University of Washington, 850 Republican Street, Seattle, WA 98105, USA; Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA.
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14
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Jasmer DP, Rosa BA, Tyagi R, Mitreva M. Rapid determination of nematode cell and organ susceptibility to toxic treatments. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:167-182. [PMID: 33125935 PMCID: PMC7593349 DOI: 10.1016/j.ijpddr.2020.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 12/28/2022]
Abstract
In research focused on the intestine of parasitic nematodes, we recently identified small molecule inhibitors toxic to intestinal cells of larval Ascaris suum (nematode intestinal toxins/toxicants; “NITs”). Some NITs had anthelmintic activity across the phylogenetic diversity of the Nematoda. The whole-worm motility inhibition assay quantified anthelmintic activity, but worm responses to NITs in relation to pathology or affected molecular pathways was not acquired. In this study we extended this research to more comprehensively determine in whole larval A. suum the cells, organ systems, molecular targets, and potential cellular pathways involved in mechanisms of toxicity leading to cell death. The experimental system utilized fluorescent nuclear probes (bisbenzimide, propidium iodide), NITs, an A. suum larval parasite culture system and transcriptional responses (RNA-seq) to NITs. The approach provides for rapid resolution of NIT-induced cell death among organ systems (e.g. intestine, excretory, esophagus, hypodermis and seam cells, and nervous), discriminates among NITs based on cell death profiles, and identifies cells and organ systems with the greatest NIT sensitivity (e.g. intestine and apparent neuronal cells adjacent to the nerve ring). Application was extended to identify cells and organs sensitive to several existing anthelmintics. This approach also resolved intestinal cell death and irreparable damage induced in adult A. suum by two NITs, establishing a new model to elucidate relevant pathologic mechanisms in adult worms. RNA-seq analysis resolved A. suum genes responsive to treatments with three NITs, identifying dihydroorotate dehydrogenase (uridine synthesis) and RAB GTPase(s) (vesicle transport) as potential targets/pathways leading to cell death. A set of genes induced by all three NITs tested suggest common stress or survival responses activated by NITs. Beyond the presented specific lines of research, elements of the overall experimental system presented in this study have broad application toward systematic development of new anthelmintics. A unique rapid cell death assay was developed for parasitic nematodes. Multiple drug-like molecules cause widespread cell death in many organs of A. suum. Multiple cell and organ systems were validated as targets for anthelmintics. Potential drug targets/pathways were implicated in activating cell death processes.
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Affiliation(s)
- Douglas P Jasmer
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 99164, USA
| | - Bruce A Rosa
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Rahul Tyagi
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Makedonka Mitreva
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA; Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, St. Louis, MO, 63110, USA; McDonnell Genome Institute, Washington University School of Medicine, St. Louis, Missouri, 63108, USA.
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15
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Zhao W, Liu JX, Guo F, Liu XG. Yeast MED2 is involved in the endoplasmic reticulum stress response and modulation of the replicative lifespan. Mech Ageing Dev 2020; 192:111381. [PMID: 33045248 DOI: 10.1016/j.mad.2020.111381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 11/28/2022]
Abstract
Saccharomyces cerevisiae MED2/YDL005C is a subunit of the mediator complex (Mediator), which is responsible for tightly controlling the transcription of protein-coding genes by mediating the interaction of RNA polymerase II with gene-specific transcription factors. Although a high-throughput analysis in yeast showed that the MED2 protein exhibits altered cellular localization under hypoxic stress, no specific function of MED2 has been described to date. In this study, we first provided evidence that MED2 is involved in the endoplasmic reticulum (ER) stress response and modulation of the replicative life span. We showed that deletion of MED2 leads to sensitivity to the ER stress inducer tunicamycin (TM) as well as a shortened replicative lifespan (RLS), accompanied by increased intracellular ROS levels and hyperpolarization of mitochondria. On the other hand, overexpression of MED2 in wild-type (WT) yeast enhanced TM resistance and extended the RLS. In addition, the IRE1-HAC1 pathway was essential for the TM resistance of MED2-overexpressing cells. Moreover, we showed that MED2 deficiency enhances ER unfolded protein response (UPR) activity compared to that in WT cells. Collectively, these results suggest the novel role of MED2 as a regulator in maintaining ER homeostasis and longevity.
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Affiliation(s)
- Wei Zhao
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Institute of Aging Research, Guangdong Medical University, Dongguan, 523808, China; Institute of Biochemistry and Molecular Biology, Guangdong Medical University, Dongguan, 523808, China
| | - Jia-Xin Liu
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Institute of Aging Research, Guangdong Medical University, Dongguan, 523808, China; Institute of Biochemistry and Molecular Biology, Guangdong Medical University, Dongguan, 523808, China
| | - Fang Guo
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Institute of Aging Research, Guangdong Medical University, Dongguan, 523808, China; Institute of Biochemistry and Molecular Biology, Guangdong Medical University, Dongguan, 523808, China
| | - Xin-Guang Liu
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Institute of Aging Research, Guangdong Medical University, Dongguan, 523808, China; Institute of Biochemistry and Molecular Biology, Guangdong Medical University, Dongguan, 523808, China.
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16
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5'-Hydroxy-6, 7, 8, 3', 4'-pentamethoxyflavone extends longevity mediated by DR-induced autophagy and oxidative stress resistance in C. elegans. GeroScience 2020; 43:759-772. [PMID: 32677024 PMCID: PMC8110683 DOI: 10.1007/s11357-020-00229-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022] Open
Abstract
5'-Hydroxy-6, 7, 8, 3', 4'-pentamethoxyflavone (5-HPF), a polymethoxyflavone compound found in dikamali gum, has been shown to exert a range of beneficial effects on health. We have previously reported that 5-HPF improves the cholinergic dysfunction and also possesses antioxidant properties in Caenorhabditis elegans. In this study, we have identified the effect of 5-HPF on the worm lifespan and its underlying molecular mechanisms. Out of the five tested pharmacological doses of 5-HPF, viz. 6.25, 12.5, 25, 50, and 100 μM, the 50 μM dose maximally extended the mean life of C. elegans by 28%. The present study revealed that 5-HPF supplementation leads to dietary restriction (DR)-like effects in the worms without altering bacterial metabolism. The analysis of mutant animals fed with 5-HPF suggested that the extended lifespan of C. elegans depends upon multiple DR-related signaling pathways, with NRF2 and FOXA being critical factors. Further investigation into the mechanistic aspects indicated that 5-HPF utilizes autophagy pathway induced by DR through the upregulation of autophagy genes bec-1 and lgg-1, evident from the increase in autophagic puncta in the seam cells of lgg-1::gfp tagged worms. This study identifies the longevity-promoting activity of 5-HPF in C. elegans regulated by oxidative stress-resistance genes and DR-induced autophagy pathway.
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17
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Blackwell TK, Sewell AK, Wu Z, Han M. TOR Signaling in Caenorhabditis elegans Development, Metabolism, and Aging. Genetics 2019; 213:329-360. [PMID: 31594908 PMCID: PMC6781902 DOI: 10.1534/genetics.119.302504] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 07/18/2019] [Indexed: 12/30/2022] Open
Abstract
The Target of Rapamycin (TOR or mTOR) is a serine/threonine kinase that regulates growth, development, and behaviors by modulating protein synthesis, autophagy, and multiple other cellular processes in response to changes in nutrients and other cues. Over recent years, TOR has been studied intensively in mammalian cell culture and genetic systems because of its importance in growth, metabolism, cancer, and aging. Through its advantages for unbiased, and high-throughput, genetic and in vivo studies, Caenorhabditis elegans has made major contributions to our understanding of TOR biology. Genetic analyses in the worm have revealed unexpected aspects of TOR functions and regulation, and have the potential to further expand our understanding of how growth and metabolic regulation influence development. In the aging field, C. elegans has played a leading role in revealing the promise of TOR inhibition as a strategy for extending life span, and identifying mechanisms that function upstream and downstream of TOR to influence aging. Here, we review the state of the TOR field in C. elegans, and focus on what we have learned about its functions in development, metabolism, and aging. We discuss knowledge gaps, including the potential pitfalls in translating findings back and forth across organisms, but also describe how TOR is important for C. elegans biology, and how C. elegans work has developed paradigms of great importance for the broader TOR field.
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Affiliation(s)
- T Keith Blackwell
- Research Division, Joslin Diabetes Center, Department of Genetics, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts
| | - Aileen K Sewell
- Department of MCDB, University of Colorado at Boulder, and
- Howard Hughes Medical Institute, Boulder, Colorado
| | - Ziyun Wu
- Research Division, Joslin Diabetes Center, Department of Genetics, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts
| | - Min Han
- Department of MCDB, University of Colorado at Boulder, and
- Howard Hughes Medical Institute, Boulder, Colorado
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18
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Piechulek A, Berwanger LC, von Mikecz A. Silica nanoparticles disrupt OPT-2/PEP-2-dependent trafficking of nutrient peptides in the intestinal epithelium. Nanotoxicology 2019; 13:1133-1148. [DOI: 10.1080/17435390.2019.1643048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Annette Piechulek
- IUF – Leibniz Research Institute for Environmental Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Lutz C. Berwanger
- IUF – Leibniz Research Institute for Environmental Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Anna von Mikecz
- IUF – Leibniz Research Institute for Environmental Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
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The longevity-promoting factor, TCER-1, widely represses stress resistance and innate immunity. Nat Commun 2019; 10:3042. [PMID: 31316054 PMCID: PMC6637209 DOI: 10.1038/s41467-019-10759-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 05/29/2019] [Indexed: 01/01/2023] Open
Abstract
Stress resistance and longevity are positively correlated but emerging evidence indicates that they are physiologically distinct. Identifying factors with distinctive roles in these processes is challenging because pro-longevity genes often enhance stress resistance. We demonstrate that TCER-1, the Caenorhabditis elegans homolog of human transcription elongation and splicing factor, TCERG1, has opposite effects on lifespan and stress resistance. We previously showed that tcer-1 promotes longevity in germline-less C. elegans and reproductive fitness in wild-type animals. Surprisingly, tcer-1 mutants exhibit exceptional resistance against multiple stressors, including infection by human opportunistic pathogens, whereas, TCER-1 overexpression confers immuno-susceptibility. TCER-1 inhibits immunity only during fertile stages of life. Elevating its levels ameliorates the fertility loss caused by infection, suggesting that TCER-1 represses immunity to augment fecundity. TCER-1 acts through repression of PMK-1 as well as PMK-1-independent factors critical for innate immunity. Our data establish key roles for TCER-1 in coordinating immunity, longevity and fertility, and reveal mechanisms that distinguish length of life from functional aspects of aging. Resistance to stress is often associated with increased longevity. Using the model organism C. elegans the authors here show that TCER-1 enhances lifespan while at the same time increasing sensitivity to a number of biotic and abiotic stressors.
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The Foodborne Strain Lactobacillus fermentum MBC2 Triggers pept-1-Dependent Pro-Longevity Effects in Caenorhabditis elegans. Microorganisms 2019; 7:microorganisms7020045. [PMID: 30736484 PMCID: PMC6406943 DOI: 10.3390/microorganisms7020045] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/21/2019] [Accepted: 02/07/2019] [Indexed: 12/16/2022] Open
Abstract
Lactic acid bacteria (LAB) are involved in several food fermentations and many of them provide strain-specific health benefits. Herein, the probiotic potential of the foodborne strain Lactobacillus fermentum MBC2 was investigated through in vitro and in vivo approaches. Caenorhabditis elegans was used as an in vivo model to analyze pro-longevity and anti-aging effects. L. fermentum MBC2 showed a high gut colonization capability compared to E. coli OP50 (OP50) or L.rhamnosus GG (LGG). Moreover, analysis of pumping rate, lipofuscin accumulation, and body bending showed anti-aging effects in L. fermentum MBC2-fed worms. Studies on PEPT-1 mutants demonstrated that pept-1 gene was involved in the anti-aging processes mediated by this bacterial strain through DAF-16, whereas the oxidative stress protection was PEPT-1 independent. Moreover, analysis of acid tolerance, bile tolerance, and antibiotic susceptibility were evaluated. L. fermentum MBC2 exerted beneficial effects on nematode lifespan, influencing energy metabolism and oxidative stress resistance, resulted in being tolerant to acidic pH and able to adhere to Caco-2 cells. Overall, these findings provide new insight for application of this strain in the food industry as a newly isolated functional starter. Furthermore, these results will also shed light on C. elegans molecular players involved in host-microbe interactions.
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Gottschling DC, Döring F. Is C. elegans a suitable model for nutritional science? GENES AND NUTRITION 2019; 14:1. [PMID: 30651890 PMCID: PMC6327375 DOI: 10.1186/s12263-018-0625-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 12/05/2018] [Indexed: 02/14/2023]
Abstract
The suitability of C. elegans as a model for the question of nutritional science is a controversial topic. The discussion makes clear that C. elegans is its own best model for revealing, via genetic approaches, biological principles of nutritional behavior, and the biochemical function of vitamins. In this case, the model has a discovery function. Worm research serves also in the identification of nutrition-dependent pathways that could be used for novel approaches in human nutritional studies. This heuristic function of the model guides the applied nutrition research in an innovative direction. Since the nutrition and metabolism for the worm and man differ from each other somewhat strongly, results of nutritional studies in C. elegans are not directly applicable to human nutrition. In general, the C. elegans model is primarily appropriate for explaining the causality of general species’ nutritional phenotypes. Experience tells us that the analysis of drastic nutritional phenotypes in C. elegans has the potential to enrich the canon of knowledge of nutritional science.
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Affiliation(s)
- Dieter-Christian Gottschling
- Department of Human Nutrition and Food Research, University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany
| | - Frank Döring
- Department of Human Nutrition and Food Research, University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany
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22
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Mirisola MG. Diet and Calorie Restriction. ENCYCLOPEDIA OF GERONTOLOGY AND POPULATION AGING 2019:1-10. [DOI: 10.1007/978-3-319-69892-2_123-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 08/02/2019] [Indexed: 09/02/2023]
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23
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Spanier B, Wallwitz J, Zapoglou D, Idrissou BMG, Fischer C, Troll M, Petzold K, Daniel H. The Reproduction Rate of Peptide Transporter PEPT-1 Deficient C. elegans Is Dependent on Dietary Glutamate Supply. Front Mol Biosci 2018; 5:109. [PMID: 30560135 PMCID: PMC6284198 DOI: 10.3389/fmolb.2018.00109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/15/2018] [Indexed: 01/19/2023] Open
Abstract
Intestinal absorption of dietary amino acids is mediated via two routes. Free amino acids released by hydrolysis of dietary proteins are taken up by a multitude of amino acid transporters while di- and tripeptides released are taken up by the peptide transporter PEPT-1. Loss of PEPT-1 impairs growth, post-embryonic development and reproduction in Caenorhabditis elegans, and supplementation with a mixture of all L-amino acids only partially rescues fertility. In the present study, we demonstrate that dietary L-glutamate is the responsible amino acid that can increase fertility in hermaphrodite pept-1 worms. This effect was associated with a significantly higher uptake of glutamate/aspartate in pept-1 than in wildtype C. elegans. Furthermore, we found that the intestinal transporter proteins SNF-5 of the solute carrier SLC6 family of nutrient amino acid transporters (NAT) and AAT-6 of the SLC7 family as the light subunit of a heteromeric amino acid transporter (HAT) play a key role in glutamate homeostasis in pept-1 C. elegans. Genes encoding these transporters are highly expressed and upon silencing a 95% reduced fertility (snf-5) and sterility (aat-6) was observed. A subsequent L-glutamate supplementation failed to rescue these phenotypes. Dietary glutamate supplementation did neither influence the feeding frequency, nor did it improve mating efficiency of pept-1 males. Most strikingly, pept-1 were more prone to habituation to repeated gentle touch stimuli than wildtype C. elegans, and dietary glutamate supply was sufficient to alter this behavioral output by restoring the mechanosensory response to wildtype levels. Taken together, our data demonstrate a key role of L-glutamate in amino acid homeostasis in C. elegans lacking the peptide transporter in the intestine and demonstrate its distinct role in reproduction and for neural circuits mediating touch sensitivity.
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Affiliation(s)
- Britta Spanier
- Nutritional Physiology, Technische Universität München, Munich, Germany
| | | | - Despoina Zapoglou
- Nutritional Physiology, Technische Universität München, Munich, Germany
| | | | - Christine Fischer
- Nutritional Physiology, Technische Universität München, Munich, Germany
| | - Martina Troll
- Nutritional Physiology, Technische Universität München, Munich, Germany
| | - Katrin Petzold
- Nutritional Physiology, Technische Universität München, Munich, Germany
| | - Hannelore Daniel
- Nutritional Physiology, Technische Universität München, Munich, Germany
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Physiological Starvation Promotes Caenorhabditis elegans Vulval Induction. G3-GENES GENOMES GENETICS 2018; 8:3069-3081. [PMID: 30037804 PMCID: PMC6118308 DOI: 10.1534/g3.118.200449] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studying how molecular pathways respond to ecologically relevant environmental variation is fundamental to understand organismal development and its evolution. Here we characterize how starvation modulates Caenorhabditis elegans vulval cell fate patterning – an environmentally sensitive process, with a nevertheless robust output. Past research has shown many vulval mutants affecting EGF-Ras-MAPK, Delta-Notch and Wnt pathways to be suppressed by environmental factors, such as starvation. Here we aimed to resolve previous, seemingly contradictory, observations on how starvation modulates levels of vulval induction. Using the strong starvation suppression of the Vulvaless phenotype of lin-3/egf reduction-of-function mutations as an experimental paradigm, we first tested for a possible involvement of the sensory system in relaying starvation signals to affect vulval induction: mutation of various sensory inputs, DAF-2/Insulin or DAF-7/TGF-β signaling did not abolish lin-3(rf) starvation suppression. In contrast, nutrient deprivation induced by mutation of the intestinal peptide transporter gene pept-1 or the TOR pathway component rsks-1 (the ortholog of mammalian P70S6K) very strongly suppressed lin-3(rf) mutant phenotypes. Therefore, physiologically starved animals induced by these mutations tightly recapitulated the effects of external starvation on vulval induction. While both starvation and pept-1 RNAi were sufficient to increase Ras and Notch pathway activities in vulval cells, the highly penetrant Vulvaless phenotype of a tissue-specific null allele of lin-3 was not suppressed by either condition. This and additional results indicate that partial lin-3 expression is required for starvation to affect vulval induction. These results suggest a cross-talk between nutrient deprivation, TOR-S6K and EGF-Ras-MAPK signaling during C. elegans vulval induction.
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25
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Alghamdi OA, King N, Andronicos NM, Jones GL, Chami B, Witting PK, Moens PDJ. Molecular changes to the rat renal cotransporters PEPT1 and PEPT2 due to ageing. Mol Cell Biochem 2018; 452:71-82. [DOI: 10.1007/s11010-018-3413-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022]
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26
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Spanier B, Rohm F. Proton Coupled Oligopeptide Transporter 1 (PepT1) Function, Regulation, and Influence on the Intestinal Homeostasis. Compr Physiol 2018; 8:843-869. [DOI: 10.1002/cphy.c170038] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Viennois E, Pujada A, Zen J, Merlin D. Function, Regulation, and Pathophysiological Relevance of the POT Superfamily, Specifically PepT1 in Inflammatory Bowel Disease. Compr Physiol 2018; 8:731-760. [PMID: 29687900 DOI: 10.1002/cphy.c170032] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mammalian members of the proton-coupled oligopeptide transporter family are integral membrane proteins that mediate the cellular uptake of di/tripeptides and peptide-like drugs and couple substrate translocation to the movement of H+ , with the transmembrane electrochemical proton gradient providing the driving force. Peptide transporters are responsible for the (re)absorption of dietary and/or bacterial di- and tripeptides in the intestine and kidney and maintaining homeostasis of neuropeptides in the brain. These proteins additionally contribute to absorption of a number of pharmacologically important compounds. In this overview article, we have provided updated information on the structure, function, expression, localization, and activities of PepT1 (SLC15A1), PepT2 (SLC15A2), PhT1 (SLC15A4), and PhT2 (SLC15A3). Peptide transporters, in particular, PepT1 are discussed as drug-delivery systems in addition to their implications in health and disease. Particular emphasis has been placed on the involvement of PepT1 in the physiopathology of the gastrointestinal tract, specifically, its role in inflammatory bowel diseases. © 2018 American Physiological Society. Compr Physiol 8:731-760, 2018.
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Affiliation(s)
- Emilie Viennois
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Adani Pujada
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Jane Zen
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Didier Merlin
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA.,Veterans Affairs Medical Center, Decatur, Georgia, USA
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Alanyl-glutamine but not glycyl-glutamine improved the proliferation of enterocytes as glutamine substitution in vitro. Amino Acids 2017; 49:2023-2031. [PMID: 28861626 DOI: 10.1007/s00726-017-2460-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/26/2017] [Indexed: 10/19/2022]
Abstract
The synthetic dipeptides alanyl-glutamine (Ala-Gln) and glycyl-glutamine (Gly-Gln) are used as Gln substitution to provide energy source in the gastrointestinal tract due to their high solubility and stability. This study aimed to investigate the effects of Gln, Ala-Gln and Gly-Gln on mitochondrial respiration and protein turnover of enterocytes. Intestinal porcine epithelial cells (IPEC-J2) were cultured for 2 days in Dulbecco's modified Eagle's-F12 Ham medium (DMEM-F12) containing 2.5 mM Gln, Ala-Gln or Gly-Gln. Results from 5-ethynyl-2'-deoxyuridine incorporation and flow cytometry analysis indicated that there were no differences in proliferation between free Gln and Ala-Gln-treated cells, whereas Gly-Gln treatment inhibited the cell growth compared with Gln treatment. Significantly lower mRNA expressions of Sp1 and PepT1 were also observed in Gly-Gln-treated cells than that of Ala-Gln treatment. Ala-Gln treatment increased the basal respiration and ATP production, compared with free Gln and Gly-Gln treatments. There were no differences in protein turnover between free Gln and Ala-Gln-treated cells, but Gly-Gln treatment reduced protein synthesis and increased protein degradation. Ala-Gln treatment stimulated mTOR activation whereas Gly-Gln decreased mTOR phosphorylation and increased the UB protein expression compared with free Gln treatment. These results indicate that Ala-Gln has the very similar functional profile to free Gln in porcine enterocytes in vitro and can be substituted Gln as energy and protein sources in the gastrointestinal tract.
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Lind MI, Chen HY, Cortazar-Chinarro M, Maklakov AA. Rapamycin additively extends lifespan in short- and long-lived lines of the nematode Caenorhabditis remanei. Exp Gerontol 2017; 90:79-82. [DOI: 10.1016/j.exger.2017.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/07/2016] [Accepted: 01/19/2017] [Indexed: 01/09/2023]
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Di- and tripeptide transport in vertebrates: the contribution of teleost fish models. J Comp Physiol B 2016; 187:395-462. [PMID: 27803975 DOI: 10.1007/s00360-016-1044-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/12/2016] [Accepted: 10/20/2016] [Indexed: 02/06/2023]
Abstract
Solute Carrier 15 (SLC15) family, alias H+-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their role in the cellular uptake of di- and tripeptides (di/tripeptides) and peptide-like molecules. Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from dietary protein digestion, while SLC15A2 (PEPT2) mainly allows renal tubular reabsorption of di/tripeptides from ultrafiltration, SLC15A3 (PHT2) and SLC15A4 (PHT1) possibly interact with di/tripeptides and histidine in certain immune cells, and SLC15A5 has unknown function. Our understanding of this family in vertebrates has steadily increased, also due to the surge of genomic-to-functional information from 'non-conventional' animal models, livestock, poultry, and aquaculture fish species. Here, we review the literature on the SLC15 transporters in teleost fish with emphasis on SLC15A1 (PEPT1), one of the solute carriers better studied amongst teleost fish because of its relevance in animal nutrition. We report on the operativity of the transporter, the molecular diversity, and multiplicity of structural-functional solutions of the teleost fish orthologs with respect to higher vertebrates, its relevance at the intersection of the alimentary and osmoregulative functions of the gut, its response under various physiological states and dietary solicitations, and its possible involvement in examples of total body plasticity, such as growth and compensatory growth. By a comparative approach, we also review the few studies in teleost fish on SLC15A2 (PEPT2), SLC15A4 (PHT1), and SLC15A3 (PHT2). By representing the contribution of teleost fish to the knowledge of the physiology of di/tripeptide transport and transporters, we aim to fill the gap between higher and lower vertebrates.
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Wei J, Damania A, Gao X, Liu Z, Mejia R, Mitreva M, Strych U, Bottazzi ME, Hotez PJ, Zhan B. The hookworm Ancylostoma ceylanicum intestinal transcriptome provides a platform for selecting drug and vaccine candidates. Parasit Vectors 2016; 9:518. [PMID: 27677574 PMCID: PMC5039805 DOI: 10.1186/s13071-016-1795-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/12/2016] [Indexed: 12/02/2022] Open
Abstract
Background The intestine of hookworms contains enzymes and proteins involved in the blood-feeding process of the parasite and is therefore a promising source of possible vaccine antigens. One such antigen, the hemoglobin-digesting intestinal aspartic protease known as Na-APR-1 from the human hookworm Necator americanus, is currently a lead candidate antigen in clinical trials, as is Na-GST-1 a heme-detoxifying glutathione S-transferase. Methods In order to discover additional hookworm vaccine antigens, messenger RNA was obtained from the intestine of male hookworms, Ancylostoma ceylanicum, maintained in hamsters. RNA-seq was performed using Illumina high-throughput sequencing technology. The genes expressed in the hookworm intestine were compared with those expressed in the whole worm and those genes overexpressed in the parasite intestine transcriptome were further analyzed. Results Among the lead transcripts identified were genes encoding for proteolytic enzymes including an A. ceylanicum APR-1, but the most common proteases were cysteine-, serine-, and metallo-proteases. Also in abundance were specific transporters of key breakdown metabolites, including amino acids, glucose, lipids, ions and water; detoxifying and heme-binding glutathione S-transferases; a family of cysteine-rich/antigen 5/pathogenesis-related 1 proteins (CAP) previously found in high abundance in parasitic nematodes; C-type lectins; and heat shock proteins. These candidates will be ranked for downstream antigen target selection based on key criteria including abundance, uniqueness in the parasite versus the vertebrate host, as well as solubility and yield of expression. Conclusion The intestinal transcriptome of A. ceylanicum provides useful information for the identification of proteins involved in the blood-feeding process, representing a first step towards a reverse vaccinology approach to a human hookworm vaccine. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1795-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junfei Wei
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ashish Damania
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xin Gao
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, 63108, USA
| | - Zhuyun Liu
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Rojelio Mejia
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Makedonka Mitreva
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, 63108, USA.,Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63108, USA
| | - Ulrich Strych
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Maria Elena Bottazzi
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Biology, Baylor University, Waco, TX, 76706, USA
| | - Peter J Hotez
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Biology, Baylor University, Waco, TX, 76706, USA
| | - Bin Zhan
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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Abstract
One of the original hypotheses of organismal longevity posits that aging is the natural result of entropy on the cells, tissues, and organs of the animal—a slow, inexorable slide into nonfunctionality caused by stochastic degradation of its parts. We now have evidence that aging is instead at least in part genetically regulated. Many mutations have been discovered to extend lifespan in organisms of all complexities, from yeast to mammals. The study of metazoan model organisms, such as Caenorhabditis elegans, has been instrumental in understanding the role of genetics in the cell biology of aging. Longevity mutants across the spectrum of model organisms demonstrate that rates of aging are regulated through genetic control of cellular processes. The regulation and subsequent breakdown of cellular processes represent a programmatic decision by the cell to either continue or abandon maintenance procedures with age. Our understanding of cell biological processes involved in regulating aging have been particularly informed by longevity mutants and treatments, such as reduced insulin/IGF-1 signaling and dietary restriction, which are critical in determining the distinction between causes of and responses to aging and have revealed a set of downstream targets that participate in a range of cell biological activities. Here we briefly review some of these important cellular processes.
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Affiliation(s)
- Race DiLoreto
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Coleen T Murphy
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
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Chapin HC, Okada M, Merz AJ, Miller DL. Tissue-specific autophagy responses to aging and stress in C. elegans. Aging (Albany NY) 2016; 7:419-34. [PMID: 26142908 PMCID: PMC4505168 DOI: 10.18632/aging.100765] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cellular function relies on a balance between protein synthesis and breakdown. Macromolecular breakdown through autophagy is broadly required for cellular and tissue development, function, and recovery from stress. While Caenorhabditis elegans is frequently used to explore cellular responses to development and stress, the most common assays for autophagy in this system lack tissue-level resolution. Different tissues within an organism have unique functional characteristics and likely vary in their reliance on autophagy under different conditions. To generate a tissue-specific map of autophagy in C. elegans we used a dual fluorescent protein (dFP) tag that releases monomeric fluorescent protein (mFP) upon arrival at the lysosome. Tissue-specific expression of dFP::LGG-1 revealed autophagic flux in all tissues, but mFP accumulation was most dramatic in the intestine. We also observed variable responses to stress: starvation increased autophagic mFP release in all tissues, whereas anoxia primarily increased intestinal autophagic flux. We observed autophagic flux with tagged LGG-1, LGG-2, and two autophagic cargo reporters: a soluble cytoplasmic protein, and mitochondrial TOMM-7. Finally, an increase in mFP in older worms was consistent with an age-dependent shift in proteostasis. These novel measures of autophagic flux in C. elegans reveal heterogeneity in autophagic response across tissues during stress and aging.
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Affiliation(s)
- Hannah C Chapin
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Megan Okada
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Alexey J Merz
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Dana L Miller
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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Mondo complexes regulate TFEB via TOR inhibition to promote longevity in response to gonadal signals. Nat Commun 2016; 7:10944. [PMID: 27001890 DOI: 10.1038/ncomms10944] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 02/03/2016] [Indexed: 12/18/2022] Open
Abstract
Germline removal provokes longevity in several species and shifts resources towards survival and repair. Several Caenorhabditis elegans transcription factors regulate longevity arising from germline removal; yet, how they work together is unknown. Here we identify a Myc-like HLH transcription factor network comprised of Mondo/Max-like complex (MML-1/MXL-2) to be required for longevity induced by germline removal, as well as by reduced TOR, insulin/IGF signalling and mitochondrial function. Germline removal increases MML-1 nuclear accumulation and activity. Surprisingly, MML-1 regulates nuclear localization and activity of HLH-30/TFEB, a convergent regulator of autophagy, lysosome biogenesis and longevity, by downregulating TOR signalling via LARS-1/leucyl-transfer RNA synthase. HLH-30 also upregulates MML-1 upon germline removal. Mammalian MondoA/B and TFEB show similar mutual regulation. MML-1/MXL-2 and HLH-30 transcriptomes show both shared and preferential outputs including MDL-1/MAD-like HLH factor required for longevity. These studies reveal how an extensive interdependent HLH transcription factor network distributes responsibility and mutually enforces states geared towards reproduction or survival.
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35
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Dietary Restriction and Nutrient Balance in Aging. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:4010357. [PMID: 26682004 PMCID: PMC4670908 DOI: 10.1155/2016/4010357] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 07/23/2015] [Accepted: 07/28/2015] [Indexed: 12/25/2022]
Abstract
Dietary regimens that favour reduced calorie intake delay aging and age-associated diseases. New evidences revealed that nutritional balance of dietary components without food restriction increases lifespan. Particular nutrients as several nitrogen sources, proteins, amino acid, and ammonium are implicated in life and healthspan regulation in different model organisms from yeast to mammals. Aging and dietary restriction interact through partially overlapping mechanisms in the activation of the conserved nutrient-signalling pathways, mainly the insulin/insulin-like growth factor (IIS) and the Target Of Rapamycin (TOR). The specific nutrients of dietary regimens, their balance, and how they interact with different genes and pathways are currently being uncovered. Taking into account that dietary regimes can largely influence overall human health and changes in risk factors such as cholesterol level and blood pressure, these new findings are of great importance to fully comprehend the interplay between diet and humans health.
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Mohandas N, Young ND, Jabbar A, Korhonen PK, Koehler AV, Hall RS, Hu M, Hofmann A, Gasser RB. The complement of family M1 aminopeptidases of Haemonchus contortus--Biotechnological implications. Biotechnol Adv 2015; 34:65-76. [PMID: 26597954 DOI: 10.1016/j.biotechadv.2015.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 10/04/2015] [Accepted: 10/10/2015] [Indexed: 01/03/2023]
Abstract
Although substantial research has been focused on the 'hidden antigen' H11 of Haemonchus contortus as a vaccine against haemonchosis in small ruminants, little is know about this and related aminopeptidases. In the present article, we reviewed genomic and transcriptomic data sets to define, for the first time, the complement of aminopeptidases (designated Hc-AP-1 to Hc-AP-13) of the family M1 with homologues in Caenorhabditis elegans, characterised by zinc-binding (HEXXH) and exo-peptidase (GAMEN) motifs. The three previously published H11 isoforms (accession nos. X94187, FJ481146 and AJ249941) had most sequence similarity to Hc-AP-2 and Hc-AP-8, whereas unpublished isoforms (accession nos. AJ249942 and AJ311316) were both most similar to Hc-AP-3. The aminopeptidases characterised here had homologues in C. elegans. Hc-AP-1 to Hc-AP-8 were most similar in amino acid sequence (28-41%) to C. elegans T07F10.1; Hc-AP-9 and Hc-AP-10 to C. elegans PAM-1 (isoform b) (53-54% similar); Hc-AP-11 and Hc-AP-12 to C. elegans AC3.5 and Y67D8C.9 (26% and 50% similar, respectively); and Hc-AP-13 to C. elegans C42C1.11 and ZC416.6 (50-58% similar). Comparative analysis suggested that Hc-AP-1 to Hc-AP-8 play roles in digestion, metabolite excretion, neuropeptide processing and/or osmotic regulation, with Hc-AP-4 and Hc-AP-7 having male-specific functional roles. The analysis also indicated that Hc-AP-9 and Hc-AP-10 might be involved in the degradation of cyclin (B3) and required to complete meiosis. Hc-AP-11 represents a leucyl/cystinyl aminopeptidase, predicted to have metallopeptidase and zinc ion binding activity, whereas Hc-AP-12 likely encodes an aminopeptidase Q homologue also with these activities and a possible role in gonad function. Finally, Hc-AP-13 is predicted to encode an aminopeptidase AP-1 homologue of C. elegans with hydrolase activity, suggested to operate, possibly synergistically with a PEPT-1 ortholog, as an oligopeptide transporter in the gut for protein uptake and normal development and/or reproduction of the worm. An appraisal of structure-based amino acid sequence alignments revealed that all conceptually translated Hc-AP proteins, with the exception of Hc-AP-12, adopt a topology similar to those observed for the two subgroups of mammalian M1 aminopeptidases, which possess either three (I, II and IV) or four (I-IV) domains. In contrast, Hc-AP-12 lacks the N-terminal domain (I), but possesses a substantially expanded domain III. Although further work needs to be done to assess amino acid sequence conservation of the different aminopeptidases among individual worms within and among H. contortus populations, we hope that these insights will support future localisation, structural and functional studies of these molecules in H. contortus as well as facilitate future assessments of a recombinant subunit or cocktail vaccine against haemonchosis.
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Affiliation(s)
- Namitha Mohandas
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Neil D Young
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Abdul Jabbar
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Pasi K Korhonen
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Anson V Koehler
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Ross S Hall
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Min Hu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Andreas Hofmann
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia; Structural Chemistry Program, Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland 4111, Australia.
| | - Robin B Gasser
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia; State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
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Lind MI, Zwoinska MK, Meurling S, Carlsson H, Maklakov AA. Sex-specific Tradeoffs With Growth and Fitness Following Life-span Extension by Rapamycin in an Outcrossing Nematode,Caenorhabditis remanei. J Gerontol A Biol Sci Med Sci 2015; 71:882-90. [DOI: 10.1093/gerona/glv174] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 09/14/2015] [Indexed: 01/05/2023] Open
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Daniel H, Zietek T. Taste and move: glucose and peptide transporters in the gastrointestinal tract. Exp Physiol 2015; 100:1441-50. [DOI: 10.1113/ep085029] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/26/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Hannelore Daniel
- Nutritional Physiology; Technische Universität München; 85350 Freising Germany
- ZIEL Institute for Food & Health; 85350 Freising Germany
| | - Tamara Zietek
- Nutritional Physiology; Technische Universität München; 85350 Freising Germany
- ZIEL Institute for Food & Health; 85350 Freising Germany
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rBTI extends Caenorhabditis elegans lifespan by mimicking calorie restriction. Exp Gerontol 2015; 67:62-71. [DOI: 10.1016/j.exger.2015.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/01/2015] [Accepted: 05/05/2015] [Indexed: 01/19/2023]
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Stegehake D, Kurosinski MA, Schürmann S, Daniel J, Lüersen K, Liebau E. Polyamine-independent Expression of Caenorhabditis elegans Antizyme. J Biol Chem 2015; 290:18090-18101. [PMID: 26032421 DOI: 10.1074/jbc.m115.644385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Indexed: 11/06/2022] Open
Abstract
Degradation of ornithine decarboxylase, the rate-limiting enzyme of polyamine biosynthesis, is promoted by the protein antizyme. Expression of antizyme is positively regulated by rising polyamine concentrations that induce a +1 translational frameshift required for production of the full-length protein. Antizyme itself is negatively regulated by the antizyme inhibitor. In our study, the regulation of Caenorhabditis elegans antizyme was investigated, and the antizyme inhibitor was identified. By applying a novel GFP-based method to monitor antizyme frameshifting in vivo, we show that the induction of translational frameshifting also occurs under stressful conditions. Interestingly, during starvation, the initiation of frameshifting was independent of polyamine concentrations. Because frameshifting was also prevalent in a polyamine auxotroph double mutant, a polyamine-independent regulation of antizyme frameshifting is suggested. Polyamine-independent induction of antizyme expression was found to be negatively regulated by the peptide transporter PEPT-1, as well as the target of rapamycin, but not by the daf-2 insulin signaling pathway. Stress-dependent expression of C. elegans antizyme occurred morely slowly than expression in response to increased polyamine levels, pointing to a more general reaction to unfavorable conditions and a diversion away from proliferation and reproduction toward conservation of energy. Interestingly, antizyme expression was found to drastically increase in aging individuals in a postreproductive manner. Although knockdown of antizyme did not affect the lifespan of C. elegans, knockdown of the antizyme inhibitor led to a significant reduction in lifespan. This is most likely caused by an increase in antizyme-mediated degradation of ornithine decarboxylase-1 and a resulting reduction in cellular polyamine levels.
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Affiliation(s)
- Dirk Stegehake
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Marc-André Kurosinski
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Sabine Schürmann
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Jens Daniel
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Kai Lüersen
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Eva Liebau
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany.
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Impact of a Complex Food Microbiota on Energy Metabolism in the Model Organism Caenorhabditis elegans. BIOMED RESEARCH INTERNATIONAL 2015; 2015:621709. [PMID: 25961031 PMCID: PMC4417589 DOI: 10.1155/2015/621709] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 11/11/2014] [Indexed: 02/03/2023]
Abstract
The nematode Caenorhabditis elegans is widely used as a model system for research on aging, development, and host-pathogen interactions. Little is currently known about the mechanisms underlying the effects exerted by foodborne microbes. We took advantage of C. elegans to evaluate the impact of foodborne microbiota on well characterized physiological features of the worms. Foodborne lactic acid bacteria (LAB) consortium was used to feed nematodes and its composition was evaluated by 16S rDNA analysis and strain typing before and after colonization of the nematode gut. Lactobacillus delbrueckii, L. fermentum, and Leuconostoc lactis were identified as the main species and shown to display different worm gut colonization capacities. LAB supplementation appeared to decrease nematode lifespan compared to the animals fed with the conventional Escherichia coli nutrient source or a probiotic bacterial strain. Reduced brood size was also observed in microbiota-fed nematodes. Moreover, massive accumulation of lipid droplets was revealed by BODIPY staining. Altered expression of nhr-49, pept-1, and tub-1 genes, associated with obesity phenotypes, was demonstrated by RT-qPCR. Since several pathways are evolutionarily conserved in C. elegans, our results highlight the nematode as a valuable model system to investigate the effects of a complex microbial consortium on host energy metabolism.
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Lee D, Hwang W, Artan M, Jeong DE, Lee SJ. Effects of nutritional components on aging. Aging Cell 2015; 14:8-16. [PMID: 25339542 PMCID: PMC4326908 DOI: 10.1111/acel.12277] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2014] [Indexed: 12/11/2022] Open
Abstract
Nutrients including carbohydrates, proteins, lipids, vitamins, and minerals regulate various physiological processes and are essential for the survival of organisms. Reduced overall caloric intake delays aging in various organisms. However, the role of each nutritional component in the regulation of lifespan is not well established. In this review, we describe recent studies focused on the regulatory role of each type of nutrient in aging. Moreover, we will discuss how the amount or composition of each nutritional component may influence longevity or health in humans.
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Affiliation(s)
- Dongyeop Lee
- Department of Life Sciences; Pohang University of Science and Technology; Pohang Gyeongbuk South Korea
| | - Wooseon Hwang
- Department of Life Sciences; Pohang University of Science and Technology; Pohang Gyeongbuk South Korea
| | - Murat Artan
- Information Technology Convergence Engineering; Pohang University of Science and Technology; Pohang Gyeongbuk South Korea
| | - Dae-Eun Jeong
- Department of Life Sciences; Pohang University of Science and Technology; Pohang Gyeongbuk South Korea
| | - Seung-Jae Lee
- Department of Life Sciences; Pohang University of Science and Technology; Pohang Gyeongbuk South Korea
- Information Technology Convergence Engineering; Pohang University of Science and Technology; Pohang Gyeongbuk South Korea
- School of Interdisciplinary Bioscience and Bioengineering; Pohang University of Science and Technology; Pohang Gyeongbuk 790-784 South Korea
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43
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Kupiec M, Weisman R. TOR links starvation responses to telomere length maintenance. Cell Cycle 2014; 11:2268-71. [DOI: 10.4161/cc.20401] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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44
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Lemieux GA, Ashrafi K. Insights and challenges in using C. elegans for investigation of fat metabolism. Crit Rev Biochem Mol Biol 2014; 50:69-84. [PMID: 25228063 DOI: 10.3109/10409238.2014.959890] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
C. elegans provides a genetically tractable system for deciphering the homeostatic mechanisms that underlie fat regulation in intact organisms. Here, we provide an overview of the recent advances in the C. elegans fat field with particular attention to studies of C. elegans lipid droplets, the complex links between lipases, autophagy, and lifespan, and analyses of key transcriptional regulatory mechanisms that coordinate lipid homeostasis. These studies demonstrate the ancient origins of mammalian and C. elegans fat regulatory pathways and highlight how C. elegans is being used to identify and analyze novel lipid pathways that are then shown to function similarly in mammals. Despite its many advantages, study of fat regulation in C. elegans is currently faced with a number of conceptual and methodological challenges. We critically evaluate some of the assumptions in the field and highlight issues that we believe should be taken into consideration when interpreting lipid content data in C. elegans.
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Affiliation(s)
- George A Lemieux
- Department of Physiology, University of California , San Francisco, CA , USA
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45
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Abstract
The inhibition of the central growth regulatory kinase TOR, which participates in two complexes, TORC1 and TORC2, has been a focus of metabolic and cancer studies for many years. Most studies have dealt with TORC1, the canonical target of rapamycin, and the role of this complex in autophagy, protein synthesis, and cell growth control. Recent work on TORC2 in budding and fission yeast species points to a conserved role of this lesser-known TOR complex in the survival of DNA damage. In budding yeast, TORC2 controls lipid biosynthesis and actin cytoskeleton through downstream AGC kinases, which are now, surprisingly, implicated in the survival of oxidative DNA damage. Preliminary data from mTORC2 modulation in cancer cells suggest that an extension to human chemotherapy is worth exploring.
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Affiliation(s)
- Ronit Weisman
- Department of Natural and Life Sciences, The Open University of Israel, Raanana, Israel
| | - Adiel Cohen
- Department of Natural and Life Sciences, The Open University of Israel, Raanana, Israel
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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46
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Geillinger KE, Kuhlmann K, Eisenacher M, Giesbertz P, Meyer HE, Daniel H, Spanier B. Intestinal amino acid availability via PEPT-1 affects TORC1/2 signaling and the unfolded protein response. J Proteome Res 2014; 13:3685-92. [PMID: 24999909 DOI: 10.1021/pr5002669] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The intestinal peptide transporter PEPT-1 plays an important role in development, growth, reproduction, and stress tolerance in Caenorhabditis elegans, as revealed by the severe phenotype of the pept-1-deficient strain. The reduced number of offspring and increased stress resistance were shown to result from changes in the insulin/IGF-signaling cascade. To further elucidate the regulatory network behind the phenotypic alterations in PEPT1-deficient animals, a quantitative proteome analysis combined with transcriptome profiling was applied. Various target genes of XBP-1, the major mediator of the unfolded protein response, were found to be downregulated at the mRNA and protein levels, accompanied by a reduction of spliced xbp-1 mRNA. Proteome analysis also revealed a markedly reduced content of numerous ribosomal proteins. This was associated with a reduction in the protein synthesis rate in pept-1 C. elegans, a process that is strictly regulated by the TOR (target of rapamycine) complex, the cellular sensor for free amino acids. These data argue for a central role of PEPT-1 in cellular amino acid homeostasis. In PEPT-1 deficiency, amino acid levels dropped systematically, leading to alterations in protein synthesis and in the IRE-1/XBP-1 pathway.
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Affiliation(s)
- Kerstin E Geillinger
- ZIEL Research Center of Nutrition and Food Sciences, Molecular Nutrition and Biochemistry Unit, Technische Universität München , Gregor-Mendel-Str. 2, 85350 Freising, Germany
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47
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Sluder AE, Baumeister R. From genes to drugs: target validation in Caenorhabditis elegans. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 1:171-7. [PMID: 24981388 DOI: 10.1016/j.ddtec.2004.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A central challenge in post-genomic drug discovery is selection of relevant therapeutic targets from a large pool of candidates, so that resources are invested productively. Key to meeting this challenge is demonstrating target function in disease-related pathways in vivo. The nematode Caenorhabditis elegans, a well-characterized experimental system for genetic analysis of biological regulatory pathways, provides a powerful means of assessing the impact of modulating target function on biological processes, thus facilitating selection of high-value targets.:
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Affiliation(s)
- Ann E Sluder
- Cambria Biosciences LLC, 8A Henshaw St., Woburn, MA 01801, USA.
| | - Ralf Baumeister
- Bio3/Bioinformatics and Molecular Genetics, University of Freiburg, Schaenzlestr. 1, D-79104 Freiburg, Germany
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48
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Lüersen K, Faust U, Gottschling DC, Döring F. Gait-specific adaptation of locomotor activity in response to dietary restriction in Caenorhabditis elegans. ACTA ACUST UNITED AC 2014; 217:2480-8. [PMID: 24803455 DOI: 10.1242/jeb.099382] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Locomotion is crucial for the survival of living organisms, as it allows foraging, flight and mating behaviour. In response to environmental cues, many organisms switch between alternative forms of locomotion, referred to as gaits. The nematode Caenorhabditis elegans exhibits two gaits: swimming in liquids and crawling on dense gels. The kinematics and patterns of muscle activity differ between the two gaits, with swimming being less efficient than crawling. We found that C. elegans when grown on dietary restriction (DR) plates and then tested immediately for swimming activity exhibit an accelerated frequency of body-bending swimming compared with ad libitum-fed worms, resulting in an increased swimming speed. This response is independent of the presence or absence of food bacteria in the assay liquid. In contrast, the crawling speed of DR worms on assay agar plates is decreased and influenced by food availability. Because DR also attenuates the disturbed swimming activity of worms that are deficient in the presynaptic dopamine transporter DAT-1, our data link DR-induced alterations of the swimming gait to synaptic processes. This strongly suggests a biochemical rather than a biomechanical response to DR provoked by changes in the worm's body structure. We conclude that the increase in locomotor activity in response to DR is specific to the swimming gait and might represent a survival strategy, allowing food-deprived nematodes to exit unfavourable environments.
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Affiliation(s)
- Kai Lüersen
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany
| | - Ulla Faust
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany
| | - Dieter-Christian Gottschling
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany
| | - Frank Döring
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany
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49
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Calorie restriction in mammals and simple model organisms. BIOMED RESEARCH INTERNATIONAL 2014; 2014:308690. [PMID: 24883306 PMCID: PMC4026914 DOI: 10.1155/2014/308690] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 04/13/2014] [Accepted: 04/21/2014] [Indexed: 01/01/2023]
Abstract
Calorie restriction (CR), which usually refers to a 20–40% reduction in calorie intake, can effectively prolong lifespan preventing most age-associated diseases in several species. However, recent data from both human and nonhumans point to the ratio of macronutrients rather than the caloric intake as a major regulator of both lifespan and health-span. In addition, specific components of the diet have recently been identified as regulators of some age-associated intracellular signaling pathways in simple model systems. The comprehension of the mechanisms underpinning these findings is crucial since it may increase the beneficial effects of calorie restriction making it accessible to a broader population as well.
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50
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Kennedy BK, Pennypacker JK. Drugs that modulate aging: the promising yet difficult path ahead. Transl Res 2014; 163:456-65. [PMID: 24316383 PMCID: PMC4004650 DOI: 10.1016/j.trsl.2013.11.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 11/07/2013] [Accepted: 11/12/2013] [Indexed: 12/12/2022]
Abstract
Once a backwater in medical sciences, aging research has emerged and now threatens to take the forefront. This dramatic change of stature is driven from 3 major events. First and foremost, the world is rapidly getting old. Never before have we lived in a demographic environment like today, and the trends will continue such that 20% percent of the global population of 9 billion will be over the age of 60 by 2050. Given current trends of sharply increasing chronic disease incidence, economic disaster from the impending silver tsunami may be ahead. A second major driver on the rise is the dramatic progress that aging research has made using invertebrate models such as worms, flies, and yeast. Genetic approaches using these organisms have led to hundreds of aging genes and, perhaps surprisingly, strong evidence of evolutionary conservation among longevity pathways between disparate species, including mammals. Current studies suggest that this conservation may extend to humans. Finally, small molecules such as rapamycin and resveratrol have been identified that slow aging in model organisms, although only rapamycin to date impacts longevity in mice. The potential now exists to delay human aging, whether it is through known classes of small molecules or a plethora of emerging ones. But how can a drug that slows aging become approved and make it to market when aging is not defined as a disease. Here, we discuss the strategies to translate discoveries from aging research into drugs. Will aging research lead to novel therapies toward chronic disease, prevention of disease or be targeted directly at extending lifespan?
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