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Tobin SW, Seneviratne D, Phan L, Seegobin M, Rico AL, Westby B, Kisiala A, Martic S, Brunetti CR, Emery RJN. Profiling of adenine-derived signaling molecules, cytokinins, in myotubes reveals fluctuations in response to lipopolysaccharide-induced cell stress. Physiol Rep 2023; 11:e15870. [PMID: 38040455 PMCID: PMC10691934 DOI: 10.14814/phy2.15870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/03/2023] [Accepted: 11/05/2023] [Indexed: 12/03/2023] Open
Abstract
Cytokinins (CTKs) are a diverse collection of evolutionarily conserved adenine-derived signaling molecules classically studied as phytohormones; however, their roles and production have been less studied in mammalian systems. Skeletal muscles are sensitive to cellular cues such as inflammation and in response, alter their secretome to regulate the muscle stem cell and myofiber niche. Using cultured C2C12 muscle cells, we profiled CTK levels to understand (1) whether CTKs are part of the muscle secretome and (2) whether CTKs are responsive to cellular stress. To induce cellular stress, C2C12 myotubes were treated with lipopolysaccharides (LPS) for 24 h and then media and cell fractions were collected for ultra high-performance liquid chromatography tandem mass spectrometry with electrospray ionization (UHPLC-(ESI+)-HRMS/MS) for metabolomics and CTK profiling. Across LPS-treated and control cells, 11 CTKs were detected in the extracellular space while 6 were detected intracellularly. We found that muscle cells are enriched in isopentenyladenine (iP) species (from free base, riboside to nucleotide forms), and that extracellular levels are increased after LPS treatment. Our study establishes that muscle cells express various forms of CTKs, and that CTK levels are responsive to LPS-induced cell stress, suggesting a role for CTKs in intra- and extracellular signaling of mammalian cells.
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Affiliation(s)
- Stephanie W. Tobin
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughOntarioCanada
| | - Dev Seneviratne
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughOntarioCanada
- Department of Forensic ScienceTrent UniversityPeterboroughCanada
| | - Lorna Phan
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
| | - Mark Seegobin
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughOntarioCanada
| | | | - Beth Westby
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
| | - Anna Kisiala
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
| | - Sanela Martic
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughOntarioCanada
- Department of Forensic ScienceTrent UniversityPeterboroughCanada
| | - Craig R. Brunetti
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughOntarioCanada
| | - R. J. Neil Emery
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughOntarioCanada
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Gibb M, Kisiala AB, Morrison EN, Emery RJN. The Origins and Roles of Methylthiolated Cytokinins: Evidence From Among Life Kingdoms. Front Cell Dev Biol 2020; 8:605672. [PMID: 33240900 PMCID: PMC7680852 DOI: 10.3389/fcell.2020.605672] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 10/19/2020] [Indexed: 12/24/2022] Open
Abstract
Cytokinins (CKs) are a group of adenine-derived, small signaling molecules of crucial importance for growth and multiple developmental processes in plants. Biological roles of classical CKs: isopentenyladenine (iP), trans and cis isomers of zeatin (tZ, cZ), and dihydrozeatin, have been studied extensively and their functions are well defined in many aspects of plant physiology. In parallel, extensive knowledge exists for genes involved in tRNA modifications that lead to the production of tRNA-bound methylthiolated CKs, especially in bacterial and mammalian systems. However, not much is known about the origins, fates, and possible functions of the unbound methylthiolated CKs (2MeS-CKs) in biological systems. 2MeS-CKs are the free base or riboside derivatives of iP or Z-type CKs, modified by the addition of a thiol group (–SH) at position 2 of the adenine ring that is subsequently methylated. Based on the evidence to date, these distinctive CK conjugates are derived exclusively via the tRNA degradation pathway. This review summarizes the knowledge on the probable steps involved in the biosynthesis of unbound 2MeS-CKs across diverse kingdoms of life. Furthermore, it provides examples of CK profiles of organisms from which the presence of 2MeS-CKs have been detected and confirms a close association and balance between the production of classical CKs and 2MeS-CKs. Finally, it discusses available reports regarding the possible physiological functions of 2MeS-CKs in different biological systems.
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Affiliation(s)
- Maya Gibb
- Department of Biology, Trent University, Peterborough, ON, Canada
| | - Anna B Kisiala
- Department of Biology, Trent University, Peterborough, ON, Canada
| | - Erin N Morrison
- Department of Biology, Trent University, Peterborough, ON, Canada
| | - R J Neil Emery
- Department of Biology, Trent University, Peterborough, ON, Canada
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Seegobin M, Kisiala A, Noble A, Kaplan D, Brunetti C, Emery RJN. Canis familiaris tissues are characterized by different profiles of cytokinins typical of the tRNA degradation pathway. FASEB J 2018; 32:fj201800347. [PMID: 29894666 DOI: 10.1096/fj.201800347] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Cytokinins (CKs) are a group of phytohormones essential to plant growth and development. The presence of these N6-modified adenine derivatives has also been documented in other groups of organisms, including bacteria, fungi, and insects. Thus far, however, only a single CK, N6-(Δ2-isopentenyl) adenine-9-riboside (iPR), has been identified in mammals. In plants, the nucleotide form of isopentenyladenine [iPR (either mono-, di-, or tri-) phosphate (iPRP)] is the first form of CK synthesized, and it is further modified to produce other CK types. To determine if a similar biosynthesis pathway exists in mammals, we tested for the presence of 27 CKs in a wide selection of canine organs using HPLC electrospray ionization-tandem mass spectrometry. Seven forms of CK were detected in the majority of the analyzed samples, including iPR, iPRP, cis-zeatin-9-riboside, cis-zeatin-9-riboside-5' (either mono-, di-, or triphosphate), 2-methylthio-N6-isopentenyladenine, 2-methylthio-N6-isopentenyladenosine, and 2-methylthio-zeatin. Total CK concentrations ranged from 1.96 pmol/g fresh weight (adrenal glands) to 1.40 × 103 pmol/g fresh weight (thyroid). The results of this study provide evidence that mammalian cells, like plant cells, can synthesize and process a diverse set of CKs including cis- and methylthiol-type CKs.-Seegobin, M., Kisiala, A., Noble, A., Kaplan, D., Brunetti, C., Emery, R. J. N. Canis familiaris tissues are characterized by different profiles of cytokinins typical of tRNA degradation pathway.
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Affiliation(s)
- Mark Seegobin
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | - Anna Kisiala
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | | | - David Kaplan
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Craig Brunetti
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | - R J Neil Emery
- Department of Biology, Trent University, Peterborough, Ontario, Canada
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Bartsakoulia M, Mϋller JS, Gomez-Duran A, Yu-Wai-Man P, Boczonadi V, Horvath R. Cysteine Supplementation May be Beneficial in a Subgroup of Mitochondrial Translation Deficiencies. J Neuromuscul Dis 2018; 3:363-379. [PMID: 27854233 DOI: 10.3233/jnd-160178] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Mitochondrial encephalomyopathies are severe, relentlessly progressive conditions and there are very few effective therapies available to date. We have previously suggested that in two rare forms of reversible mitochondrial disease (reversible infantile respiratory chain deficiency and reversible infantile hepatopathy) supplementation with L-cysteine can improve mitochondrial protein synthesis, since cysteine is required for the 2-thiomodification of mitochondrial tRNAs. OBJECTIVES We studied whether supplementation with L-cysteine or N-acetyl-cysteine (NAC) results in any improvement of the mitochondrial function in vitro in fibroblasts of patients with different genetic forms of abnormal mitochondrial translation. METHODS We studied in vitro in fibroblasts of patients carrying the common m.3243A>G and m.8344A>G mutations or autosomal recessive mutations in genes affecting mitochondrial translation, whether L-cysteine or N-acetyl-cysteine supplementation have an effect on mitochondrial respiratory chain function. RESULTS Here we show that supplementation with L-cysteine, but not with N-acetyl-cysteine partially rescues the mitochondrial translation defect in vitro in fibroblasts of patients carrying the m.3243A>G and m.8344A>G mutations. In contrast, N-acetyl-cysteine had a beneficial effect on mitochondrial translation in TRMU and MTO1 deficient fibroblasts. CONCLUSIONS Our results suggest that L-cysteine or N-acetyl-cysteine supplementation may be a potential treatment for selected subgroups of patients with mitochondrial translation deficiencies. Further studies are needed to explore the full potential of cysteine supplementation as a treatment for patients with mitochondrial disease.
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Affiliation(s)
- Marina Bartsakoulia
- Wellcome Trust Mitochondrial Research Centre and the John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, UK
| | - Juliane S Mϋller
- Wellcome Trust Mitochondrial Research Centre and the John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, UK
| | - Aurora Gomez-Duran
- Wellcome Trust Mitochondrial Research Centre and the John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, UK.,Present address: Department of Clinical Neurosciences, Cambridge and MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Patrick Yu-Wai-Man
- Wellcome Trust Mitochondrial Research Centre and the John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, UK.,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Veronika Boczonadi
- Wellcome Trust Mitochondrial Research Centre and the John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, UK
| | - Rita Horvath
- Wellcome Trust Mitochondrial Research Centre and the John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, UK
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Bohnsack MT, Sloan KE. The mitochondrial epitranscriptome: the roles of RNA modifications in mitochondrial translation and human disease. Cell Mol Life Sci 2017; 75:241-260. [PMID: 28752201 PMCID: PMC5756263 DOI: 10.1007/s00018-017-2598-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 07/08/2017] [Accepted: 07/17/2017] [Indexed: 11/28/2022]
Abstract
Mitochondrial protein synthesis is essential for the production of components of the oxidative phosphorylation system. RNA modifications in the mammalian mitochondrial translation apparatus play key roles in facilitating mitochondrial gene expression as they enable decoding of the non-conventional genetic code by a minimal set of tRNAs, and efficient and accurate protein synthesis by the mitoribosome. Intriguingly, recent transcriptome-wide analyses have also revealed modifications in mitochondrial mRNAs, suggesting that the concept of dynamic regulation of gene expression by the modified RNAs (the “epitranscriptome”) extends to mitochondria. Furthermore, it has emerged that defects in RNA modification, arising from either mt-DNA mutations or mutations in nuclear-encoded mitochondrial modification enzymes, underlie multiple mitochondrial diseases. Concomitant advances in the identification of the mitochondrial RNA modification machinery and recent structural views of the mitochondrial translation apparatus now allow the molecular basis of such mitochondrial diseases to be understood on a mechanistic level.
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Affiliation(s)
- Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
- Göttingen Centre for Molecular Biosciences, University of Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany.
| | - Katherine E Sloan
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
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Lamichhane TN, Arimbasseri AG, Rijal K, Iben JR, Wei FY, Tomizawa K, Maraia RJ. Lack of tRNA-i6A modification causes mitochondrial-like metabolic deficiency in S. pombe by limiting activity of cytosolic tRNATyr, not mito-tRNA. RNA (NEW YORK, N.Y.) 2016; 22:583-96. [PMID: 26857223 PMCID: PMC4793213 DOI: 10.1261/rna.054064.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/28/2015] [Indexed: 05/17/2023]
Abstract
tRNA-isopentenyl transferases (IPTases) are highly conserved enzymes that form isopentenyl-N(6)-A37 (i6A37) on subsets of tRNAs, enhancing their translation activity. Nuclear-encoded IPTases modify select cytosolic (cy-) and mitochondrial (mt-) tRNAs. Mutation in human IPTase, TRIT1, causes disease phenotypes characteristic of mitochondrial translation deficiency due to mt-tRNA dysfunction. Deletion of the Schizosaccharomyces pombe IPTase (tit1-Δ) causes slow growth in glycerol, as well as in rapamycin, an inhibitor of TOR kinase that maintains metabolic homeostasis. Schizosaccharomyces pombe IPTase modifies three different cy-tRNAs(Ser) as well as cy-tRNA(Tyr), cy-tRNA(Trp), and mt-tRNA(Trp). We show that lower ATP levels in tit1-Δ relative to tit1(+) cells are also more decreased by an inhibitor of oxidative phosphorylation, indicative of mitochondrial dysfunction. Here we asked if the tit1-Δ phenotypes are due to hypomodification of cy-tRNA or mt-tRNA. A cytosol-specific IPTase that modifies cy-tRNA, but not mt-tRNA, fully rescues the tit1-Δ phenotypes. Moreover, overexpression of cy-tRNAs also rescues the phenotypes, and cy-tRNA(Tyr) alone substantially does so. Bioinformatics indicate that cy-tRNA(Tyr) is most limiting for codon demand in tit1-Δ cells and that the cytosolic mRNAs most loaded with Tyr codons encode carbon metabolilizing enzymes, many of which are known to localize to mitochondria. Thus, S. pombe i6A37 hypomodification-associated metabolic deficiency results from hypoactivity of cy-tRNA, mostly tRNA(Tyr), and unlike human TRIT1-deficiency does not impair mitochondrial translation due to mt-tRNA hypomodification. We discuss species-specific aspects of i6A37. Specifically relevant to mitochondria, we show that its hypermodified version, ms2i6A37 (2-methylthiolated), which occurs on certain mammalian mt-tRNAs (but not cy-tRNAs), is not found in yeast.
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Affiliation(s)
- Tek N Lamichhane
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Aneeshkumar G Arimbasseri
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Keshab Rijal
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - James R Iben
- Molecular Genetics Laboratory, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Fan Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 860-0862 Kumamoto, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 860-0862 Kumamoto, Japan
| | - Richard J Maraia
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA Commissioned Corps, US Public Health Service, Rockville, Maryland 20016, USA
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