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Alao JP, Legon L, Dabrowska A, Tricolici AM, Kumar J, Rallis C. Interplays of AMPK and TOR in Autophagy Regulation in Yeast. Cells 2023; 12:cells12040519. [PMID: 36831186 PMCID: PMC9953913 DOI: 10.3390/cells12040519] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Cells survey their environment and need to balance growth and anabolism with stress programmes and catabolism towards maximum cellular bioenergetics economy and survival. Nutrient-responsive pathways, such as the mechanistic target of rapamycin (mTOR) interact and cross-talk, continuously, with stress-responsive hubs such as the AMP-activated protein kinase (AMPK) to regulate fundamental cellular processes such as transcription, protein translation, lipid and carbohydrate homeostasis. Especially in nutrient stresses or deprivations, cells tune their metabolism accordingly and, crucially, recycle materials through autophagy mechanisms. It has now become apparent that autophagy is pivotal in lifespan, health and cell survival as it is a gatekeeper of clearing damaged macromolecules and organelles and serving as quality assurance mechanism within cells. Autophagy is hard-wired with energy and nutrient levels as well as with damage-response, and yeasts have been instrumental in elucidating such connectivities. In this review, we briefly outline cross-talks and feedback loops that link growth and stress, mainly, in the fission yeast Schizosaccharomyces pombe, a favourite model in cell and molecular biology.
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Alao JP, Legon L, Rallis C. Crosstalk between the mTOR and DNA Damage Response Pathways in Fission Yeast. Cells 2021; 10:cells10020305. [PMID: 33540829 PMCID: PMC7913062 DOI: 10.3390/cells10020305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 12/14/2022] Open
Abstract
Cells have developed response systems to constantly monitor environmental changes and accordingly adjust growth, differentiation, and cellular stress programs. The evolutionarily conserved, nutrient-responsive, mechanistic target of rapamycin signaling (mTOR) pathway coordinates basic anabolic and catabolic cellular processes such as gene transcription, protein translation, autophagy, and metabolism, and is directly implicated in cellular and organismal aging as well as age-related diseases. mTOR mediates these processes in response to a broad range of inputs such as oxygen, amino acids, hormones, and energy levels, as well as stresses, including DNA damage. Here, we briefly summarize data relating to the interplays of the mTOR pathway with DNA damage response pathways in fission yeast, a favorite model in cell biology, and how these interactions shape cell decisions, growth, and cell-cycle progression. We, especially, comment on the roles of caffeine-mediated DNA-damage override. Understanding the biology of nutrient response, DNA damage and related pharmacological treatments can lead to the design of interventions towards improved cellular and organismal fitness, health, and survival.
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Affiliation(s)
- John-Patrick Alao
- ZEAB Therapeutic, University of East London, Stratford Campus, Water Lane, Stratford, London E15 4LZ, UK;
| | - Luc Legon
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, Water Lane, Stratford, London E15 4LZ, UK;
| | - Charalampos Rallis
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
- Correspondence:
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Gene Expression of Pneumocystis murina after Treatment with Anidulafungin Results in Strong Signals for Sexual Reproduction, Cell Wall Integrity, and Cell Cycle Arrest, Indicating a Requirement for Ascus Formation for Proliferation. Antimicrob Agents Chemother 2018; 62:AAC.02513-17. [PMID: 29463544 PMCID: PMC5923105 DOI: 10.1128/aac.02513-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/10/2018] [Indexed: 01/03/2023] Open
Abstract
The echinocandins are a class of antifungal agents that target β-1,3-d-glucan (BG) biosynthesis. In the ascigerous Pneumocystis species, treatment with these drugs depletes the ascus life cycle stage, which contains BG, but large numbers of forms which do not express BG remain in the infected lungs. In the present study, the gene expression profiles of Pneumocystis murina were compared between infected, untreated mice and mice treated with anidulafungin for 2 weeks to understand the metabolism of the persisting forms. Almost 80 genes were significantly up- or downregulated. Like other fungi exposed to echinocandins, genes associated with sexual replication, cell wall integrity, cell cycle arrest, and stress comprised the strongest upregulated signals in P. murina from the treated mice. The upregulation of the P. murina β-1,3-d-glucan endohydrolase and endo-1,3-glucanase was notable and may explain the disappearance of the existing asci in the lungs of treated mice since both enzymes can degrade BG. The biochemical measurement of BG in the lungs of treated mice and fluorescence microscopy with an anti-BG antibody supported the loss of BG. Downregulated signals included genes involved in cell replication, genome stability, and ribosomal biogenesis and function and the Pneumocystis-specific genes encoding the major surface glycoproteins (Msg). These studies suggest that P. murina attempted to undergo sexual replication in response to a stressed environment and was halted in any type of proliferative cycle, likely due to a lack of BG. Asci appear to be a required part of the life cycle stage of Pneumocystis, and BG may be needed to facilitate progression through the life cycle via sexual replication.
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Dudin O, Merlini L, Bendezú FO, Groux R, Vincenzetti V, Martin SG. A systematic screen for morphological abnormalities during fission yeast sexual reproduction identifies a mechanism of actin aster formation for cell fusion. PLoS Genet 2017; 13:e1006721. [PMID: 28410370 PMCID: PMC5409535 DOI: 10.1371/journal.pgen.1006721] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/28/2017] [Accepted: 03/29/2017] [Indexed: 01/15/2023] Open
Abstract
In non-motile fungi, sexual reproduction relies on strong morphogenetic changes in response to pheromone signaling. We report here on a systematic screen for morphological abnormalities of the mating process in fission yeast Schizosaccharomyces pombe. We derived a homothallic (self-fertile) collection of viable deletions, which, upon visual screening, revealed a plethora of phenotypes affecting all stages of the mating process, including cell polarization, cell fusion and sporulation. Cell fusion relies on the formation of the fusion focus, an aster-like F-actin structure that is marked by strong local accumulation of the myosin V Myo52, which concentrates secretion at the fusion site. A secondary screen for fusion-defective mutants identified the myosin V Myo51-associated coiled-coil proteins Rng8 and Rng9 as critical for the coalescence of the fusion focus. Indeed, rng8Δ and rng9Δ mutant cells exhibit multiple stable dots at the cell-cell contact site, instead of the single focus observed in wildtype. Rng8 and Rng9 accumulate on the fusion focus, dependent on Myo51 and tropomyosin Cdc8. A tropomyosin mutant allele, which compromises Rng8/9 localization but not actin binding, similarly leads to multiple stable dots instead of a single focus. By contrast, myo51 deletion does not strongly affect fusion focus coalescence. We propose that focusing of the actin filaments in the fusion aster primarily relies on Rng8/9-dependent cross-linking of tropomyosin-actin filaments.
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Affiliation(s)
- Omaya Dudin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Felipe O. Bendezú
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Raphaël Groux
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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Chao MW, Yang CH, Lin PT, Yang YH, Chuang YC, Chung MC, Tseng CY. Exposure to PM 2.5 causes genetic changes in fetal rat cerebral cortex and hippocampus. ENVIRONMENTAL TOXICOLOGY 2017; 32:1412-1425. [PMID: 27539004 DOI: 10.1002/tox.22335] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 07/29/2016] [Accepted: 07/30/2016] [Indexed: 05/06/2023]
Abstract
PM2.5 travels along the respiratory tract and enters systemic blood circulation. Studies have shown that PM2.5 increases the incidence of various diseases not only in adults but also in newborn infants. It causes chronic inflammation in pregnant women and retards fetal development. In this study, pregnant rats were exposed to PM2.5 for extended periods of time and it was found that PM2.5 exposure increased immune cells in mother rats. In addition, cytokines and free radicals rapidly accumulated in the amniotic fluid and indirectly affected the fetuses. The authors collected cerebral cortex and hippocampus samples at E18 and analyzed changes of miRNA levels. Expression levels of cortical miR-6315, miR-3588, and miR-466b-5p were upregulated, and positively correlated with the genes Pkn2 (astrocyte migration), Gorab (neuritogenesis), and Mobp (allergic encephalomyelitis). In contrast, PM2.5 decreased expression of miR-338-5p and let-7e-5p, both related to mental development. Further, PM2.5 exposure increased miR-3560 and let-7b-5p in the hippocampus, two proteins that regulate genes Oxct1 and Lin28b that control ketogenesis and glycosylation, and neural cell differentiation, respectively. miR-99b-5p, miR-92b-5p, and miR-99a-5p were decreased, leading to reduced expression of Kbtbd8 and Adam11 which reduced cell mitosis, migration, and differentiation, and inhibited learning abilities and motor coordination of the fetus. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1412-1425, 2017.
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Affiliation(s)
- Ming-Wei Chao
- Department of Bioscience Technology College of Science, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
- Center for Nanotechnology, College of Science, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
| | - Chin-Hua Yang
- Department of Diagnostic Radiology, Taoyuan General Hospital, Taoyaun, 310, Taiwan
- Departmewnt of Biomedical Engineering and Environmental Science, National Tsing Hua University, East District, Hsinchu 300, Taiwan
| | - Po-Ting Lin
- Department of Mechanical Engineering, College of Engineering, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
| | - Yu-Hsiu Yang
- Department of Biomedical Engineering College of Engineering, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
| | - Yu-Chen Chuang
- Department of Biomedical Engineering College of Engineering, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
| | - Meng-Chi Chung
- Department of Bioscience Technology College of Science, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
| | - Chia-Yi Tseng
- Center for Nanotechnology, College of Science, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
- Department of Biomedical Engineering College of Engineering, Chung Yuan Christian University, Zhongli district, Taoyaun, 320, Taiwan
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