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Zhao T, Fan J, Abu-Zaid A, Burley SK, Zheng XS. Nuclear mTOR Signaling Orchestrates Transcriptional Programs Underlying Cellular Growth and Metabolism. Cells 2024; 13:781. [PMID: 38727317 PMCID: PMC11083943 DOI: 10.3390/cells13090781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/13/2024] Open
Abstract
mTOR is a central regulator of cell growth and metabolism in response to mitogenic and nutrient signals. Notably, mTOR is not only found in the cytoplasm but also in the nucleus. This review highlights direct involvement of nuclear mTOR in regulating transcription factors, orchestrating epigenetic modifications, and facilitating chromatin remodeling. These effects intricately modulate gene expression programs associated with growth and metabolic processes. Furthermore, the review underscores the importance of nuclear mTOR in mediating the interplay between metabolism and epigenetic modifications. By integrating its functions in nutrient signaling and gene expression related to growth and metabolism, nuclear mTOR emerges as a central hub governing cellular homeostasis, malignant transformation, and cancer progression. Better understanding of nuclear mTOR signaling has the potential to lead to novel therapies against cancer and other growth-related diseases.
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Affiliation(s)
- Tinghan Zhao
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Jialin Fan
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Ahmed Abu-Zaid
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Stephen K. Burley
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- RCSB Protein Data Bank and Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, 174 Frelinghuysen Road, Piscataway, NJ 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 174 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - X.F. Steven Zheng
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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Akiyama Y, Ivanov P. Oxidative Stress, Transfer RNA Metabolism, and Protein Synthesis. Antioxid Redox Signal 2024; 40:715-735. [PMID: 37767630 PMCID: PMC11001508 DOI: 10.1089/ars.2022.0206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 09/29/2023]
Abstract
Significance: Oxidative stress refers to excessive intracellular levels of reactive oxygen species (ROS) due to an imbalance between ROS production and the antioxidant defense system. Under oxidative stress conditions, cells trigger various stress response pathways to protect themselves, among which repression of messenger RNA (mRNA) translation is one of the key hallmarks promoting cell survival. This regulation process minimizes cellular energy consumption, enabling cells to survive in adverse conditions and to promote recovery from stress-induced damage. Recent Advances: Recent studies suggest that transfer RNAs (tRNAs) play important roles in regulating translation as a part of stress response under adverse conditions. In particular, research relying on high-throughput techniques such as next-generation sequencing and mass spectrometry approaches has given us detailed information on mechanisms such as individual tRNA dynamics and crosstalk among post-transcriptional modifications. Critical Issues: Oxidative stress leads to dynamic tRNA changes, including their localization, cleavage, and alteration of expression profiles and modification patterns. Growing evidence suggests that these changes not only are tightly regulated by stress response mechanisms, but also can directly fine-tune the translation efficiency, which contributes to cell- or tissue-specific response to oxidative stress. Future Directions: In this review, we describe recent advances in the understanding of the dynamic changes of tRNAs caused by oxidative stress. We also highlight the emerging roles of tRNAs in translation regulation under the condition of oxidative stress. In addition, we discuss future perspectives in this research field. Antioxid. Redox Signal. 40, 715-735.
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Affiliation(s)
- Yasutoshi Akiyama
- Laboratory of Oncology, Pharmacy Practice and Sciences, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Japan
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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Cabarcas-Petroski S, Olshefsky G, Schramm L. MAF1 is a predictive biomarker in HER2 positive breast cancer. PLoS One 2023; 18:e0291549. [PMID: 37801436 PMCID: PMC10558074 DOI: 10.1371/journal.pone.0291549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/01/2023] [Indexed: 10/08/2023] Open
Abstract
RNA polymerase III transcription is pivotal in regulating cellular growth and frequently deregulated in various cancers. MAF1 negatively regulates RNA polymerase III transcription. Currently, it is unclear if MAF1 is universally deregulated in human cancers. Recently, MAF1 expression has been demonstrated to be altered in colorectal and liver carcinomas and Luminal B breast cancers. In this study, we analyzed clinical breast cancer datasets to determine if MAF1 alterations correlate with clinical outcomes in HER2-positive breast cancer. Using various bioinformatics tools, we screened breast cancer datasets for alterations in MAF1 expression. We report that MAF1 is amplified in 39% of all breast cancer sub-types, and the observed amplification co-occurs with MYC. MAF1 amplification correlated with increased methylation of the MAF1 promoter and MAF1 protein expression is significantly decreased in luminal, HER2-positive, and TNBC breast cancer subtypes. MAF1 protein expression is also significantly reduced in stage 2 and 3 breast cancer compared to normal and significantly decreased in all breast cancer patients, regardless of race and age. In SKBR3 and BT474 breast cancer cell lines treated with anti-HER2 therapies, MAF1 mRNA expression is significantly increased. In HER2-positive breast cancer patients, MAF1 expression significantly increases and correlates with five years of relapse-free survival in response to trastuzumab treatment, suggesting MAF1 is a predictive biomarker in breast cancer. These data suggest a role for MAF1 alterations in HER2-positive breast cancer. More extensive studies are warranted to determine if MAF1 serves as a predictive and prognostic biomarker in breast cancer.
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Affiliation(s)
| | | | - Laura Schramm
- Department of Biology, St. John’s University, Queens, NY, United States of America
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Tsang CK, Mi Q, Su G, Hwa Lee G, Xie X, D'Arcangelo G, Huang L, Steven Zheng XF. Maf1 is an intrinsic suppressor against spontaneous neural repair and functional recovery after ischemic stroke. J Adv Res 2023; 51:73-90. [PMID: 36402285 PMCID: PMC10491990 DOI: 10.1016/j.jare.2022.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/28/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Spontaneous recovery after CNS injury is often very limited and incomplete, leaving most stroke patients with permanent disability. Maf1 is known as a key growth suppressor in proliferating cells. However, its role in neuronal cells after stroke remains unclear. OBJECTIVE We aimed to investigate the mechanistic role of Maf1 in spontaneous neural repair and evaluated the therapeutic effect of targeting Maf1 on stroke recovery. METHODS We used mouse primary neurons to determine the signaling mechanism of Maf1, and the cleavage-under-targets-and-tagmentation-sequencing to map the whole-genome promoter binding sites of Maf1 in isolated mature cortical neurons. Photothrombotic stroke model was used to determine the therapeutic effect on neural repair and functional recovery by AAV-mediated Maf1 knockdown. RESULTS We found that Maf1 mediates mTOR signaling to regulate RNA polymerase III (Pol III)-dependent rRNA and tRNA transcription in mouse cortical neurons. mTOR regulates neuronal Maf1 phosphorylation and subcellular localization. Maf1 knockdown significantly increases Pol III transcription, neurite outgrowth and dendritic spine formation in neurons. Conversely, Maf1 overexpression suppresses such activities. In response to photothrombotic stroke in mice, Maf1 expression is increased and accumulates in the nucleus of neurons in the peripheral region of infarcted cortex, which is the key region for neural remodeling and repair during spontaneous recovery. Intriguingly, Maf1 knockdown in the peri-infarct cortex significantly enhances neural plasticity and functional recovery. Mechanistically, Maf1 not only interacts with the promoters and represses Pol III-transcribed genes, but also those of CREB-associated genes that are critical for promoting plasticity during neurodevelopment and neural repair. CONCLUSION These findings indicate Maf1 as an intrinsic neural repair suppressor against regenerative capability of mature CNS neurons, and suggest that Maf1 is a potential therapeutic target for enhancing functional recovery after ischemic stroke and other CNS injuries.
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Affiliation(s)
- Chi Kwan Tsang
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA.
| | - Qiongjie Mi
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China
| | - Guangpu Su
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China
| | - Gum Hwa Lee
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Xuemin Xie
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Li'an Huang
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China; Department of Neurology and Stroke Center, The First Affiliated Hospital, Jinan University Guangzhou, Guangdong, China.
| | - X F Steven Zheng
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA.
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Tyczewska A, Rzepczak A, Sobańska D, Grzywacz K. The emerging roles of tRNAs and tRNA-derived fragments during aging: Lessons from studies on model organisms. Ageing Res Rev 2023; 85:101863. [PMID: 36707034 DOI: 10.1016/j.arr.2023.101863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023]
Abstract
Aging is a gradual decline of various functions of organisms resulting in diminished abilities to protect against the environmental damage and reinforce the physiological harmony. Age-related functional declines have been thought to be passive and not regulated. However, studies on numerous model organisms, from yeast to mammals, exposed that the mechanisms of lifespan regulation are remarkably conserved throughout the evolution. Following the pioneering genetic studies in C. elegans, it has been shown that the genes related to the longevity are conserved in yeast, flies and mice. For a long time, tRNAs have been only considered as molecules transporting amino acids to the ribosome during translation. Nonetheless, it has become apparent from many biological studies that tRNAs are entangled in a variety of physiological and pathological processes. This review focuses on the emerging roles of tRNA-associated processes in aging and lifespan of model organisms. More specificaly, we present a summary on the importance of tRNA metabolism, epitranscriptome and possible roles of tRNA-derived fragments in aging and lifespan regulation. Better understanding of the basic mechanisms of aging could lead to the development of new diagnostics and treatments for aging-related diseases.
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Affiliation(s)
- Agata Tyczewska
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Alicja Rzepczak
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Daria Sobańska
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Kamilla Grzywacz
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland.
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How to Shut Down Transcription in Archaea during Virus Infection. Microorganisms 2022; 10:microorganisms10091824. [PMID: 36144426 PMCID: PMC9501531 DOI: 10.3390/microorganisms10091824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 11/16/2022] Open
Abstract
Multisubunit RNA polymerases (RNAPs) carry out transcription in all domains of life; during virus infection, RNAPs are targeted by transcription factors encoded by either the cell or the virus, resulting in the global repression of transcription with distinct outcomes for different host–virus combinations. These repressors serve as versatile molecular probes to study RNAP mechanisms, as well as aid the exploration of druggable sites for the development of new antibiotics. Here, we review the mechanisms and structural basis of RNAP inhibition by the viral repressor RIP and the crenarchaeal negative regulator TFS4, which follow distinct strategies. RIP operates by occluding the DNA-binding channel and mimicking the initiation factor TFB/TFIIB. RIP binds tightly to the clamp and locks it into one fixed position, thereby preventing conformational oscillations that are critical for RNAP function as it progresses through the transcription cycle. TFS4 engages with RNAP in a similar manner to transcript cleavage factors such as TFS/TFIIS through the NTP-entry channel; TFS4 interferes with the trigger loop and bridge helix within the active site by occlusion and allosteric mechanisms, respectively. The conformational changes in RNAP described above are universally conserved and are also seen in inactive dimers of eukaryotic RNAPI and several inhibited RNAP complexes of both bacterial and eukaryotic RNA polymerases, including inactive states that precede transcription termination. A comparison of target sites and inhibitory mechanisms reveals that proteinaceous repressors and RNAP-specific antibiotics use surprisingly common ways to inhibit RNAP function.
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Hernández-Gómez C, Hernández-Lemus E, Espinal-Enríquez J. The Role of Copy Number Variants in Gene Co-Expression Patterns for Luminal B Breast Tumors. Front Genet 2022; 13:806607. [PMID: 35432489 PMCID: PMC9010943 DOI: 10.3389/fgene.2022.806607] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/03/2022] [Indexed: 12/20/2022] Open
Abstract
Gene co-expression networks have become a usual approach to integrate the vast amounts of information coming from gene expression studies in cancer cohorts. The reprogramming of the gene regulatory control and the molecular pathways depending on such control are central to the characterization of the disease, aiming to unveil the consequences for cancer prognosis and therapeutics. There is, however, a multitude of factors which have been associated with anomalous control of gene expression in cancer. In the particular case of co-expression patterns, we have previously documented a phenomenon of loss of long distance co-expression in several cancer types, including breast cancer. Of the many potential factors that may contribute to this phenomenology, copy number variants (CNVs) have been often discussed. However, no systematic assessment of the role that CNVs may play in shaping gene co-expression patterns in breast cancer has been performed to date. For this reason we have decided to develop such analysis. In this study, we focus on using probabilistic modeling techniques to evaluate to what extent CNVs affect the phenomenon of long/short range co-expression in Luminal B breast tumors. We analyzed the co-expression patterns in chromosome 8, since it is known to be affected by amplifications/deletions during cancer development. We found that the CNVs pattern in chromosome 8 of Luminal B network does not alter the co-expression patterns significantly, which means that the co-expression program in this cancer phenotype is not determined by CNV structure. Additionally, we found that region 8q24.3 is highly dense in interactions, as well as region p21.3. The most connected genes in this network belong to those cytobands and are associated with several manifestations of cancer in different tissues. Interestingly, among the most connected genes, we found MAF1 and POLR3D, which may constitute an axis of regulation of gene transcription, in particular for non-coding RNA species. We believe that by advancing on our knowledge of the molecular mechanisms behind gene regulation in cancer, we will be better equipped, not only to understand tumor biology, but also to broaden the scope of diagnostic, prognostic and therapeutic interventions to ultimately benefit oncologic patients.
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Affiliation(s)
| | - Enrique Hernández-Lemus
- Computational Genomics Division, National Institute of Genomic Medicine, Mexico City, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico
- *Correspondence: Jesús Espinal-Enríquez, ; Enrique Hernández-Lemus,
| | - Jesús Espinal-Enríquez
- Computational Genomics Division, National Institute of Genomic Medicine, Mexico City, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico
- *Correspondence: Jesús Espinal-Enríquez, ; Enrique Hernández-Lemus,
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Zhang T, Niu Q, Wang T, Zheng X, Li H, Gao X, Chen Y, Gao H, Zhang L, Liu GE, Li J, Xu L. Comparative Transcriptomic Analysis Reveals Diverse Expression Pattern Underlying Fatty Acid Composition among Different Beef Cuts. Foods 2022; 11:foods11010117. [PMID: 35010243 PMCID: PMC8750426 DOI: 10.3390/foods11010117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 01/21/2023] Open
Abstract
Beef is an important dietary source of quality animal proteins and amino acids in human nutrition. The fatty acid composition is one of the indispensable indicators affecting nutritional value of beef. However, a comprehensive understanding of the expression changes underlying fatty acid composition in representative beef cuts is needed in cattle. This study aimed to characterize the dynamics of fatty acid composition using comparative transcriptomic analysis in five different type of beef cuts. We identified 7545 differentially expressed genes (DEGs) among 10 pair-wise comparisons. Co-expression gene network analysis identified two modules, which were significantly correlated with 2 and 20 fatty acid composition, respectively. We also identified 38 candidate genes, and functional enrichment showed that these genes were involved in fatty acid biosynthetic process and degradation, PPAR, and AMPK signaling pathway. Moreover, we observed a cluster of DEGs (e.g., SCD, LPL, FABP3, and PPARD) which were involved in the regulation of lipid metabolism and adipocyte differentiation. Our results provide some valuable insights into understanding the transcriptome regulation of candidate genes on fatty acid composition of beef cuts, and our findings may facilitate the designs of genetic selection program for beneficial fatty acid composition in beef cattle.
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Affiliation(s)
- Tianliu Zhang
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Qunhao Niu
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Tianzhen Wang
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Xu Zheng
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Haipeng Li
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Xue Gao
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Yan Chen
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Huijiang Gao
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Lupei Zhang
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - George E. Liu
- Animal Genomics and Improvement Laboratory, United States Department of Agriculture-Agricultural Research Services, Beltsville, MD 20705, USA;
| | - Junya Li
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
| | - Lingyang Xu
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (T.Z.); (Q.N.); (T.W.); (X.Z.); (H.L.); (X.G.); (Y.C.); (H.G.); (L.Z.); (J.L.)
- Correspondence:
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Chen D, Sun YY, Zhou LY, Yang S, Hong FY, Liu XD, Sun ZL, Huang J, Feng DF. Maf1 regulates axonal regeneration of retinal ganglion cells after injury. Exp Neurol 2021; 348:113948. [PMID: 34902358 DOI: 10.1016/j.expneurol.2021.113948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/25/2021] [Accepted: 12/07/2021] [Indexed: 11/25/2022]
Abstract
Retinal ganglion cells (RGCs) are the sole output neurons that carry visual information from the eye to the brain. Due to various retinal and optic nerve diseases, RGC somas and axons are vulnerable to damage and lose their regenerative capacity. A basic question is whether the manipulation of a key regulator of RGC survival can protect RGCs from retinal and optic nerve diseases. Here, we found that Maf1, a general transcriptional regulator, was upregulated in RGCs from embryonic stage to adulthood. We determined that the knockdown of Maf1 promoted the survival of RGCs and their axon regeneration through altering the activity of the PTEN/mTOR pathway, which could be blocked by rapamycin. We further observed that the inhibition of Maf1 prevented the retinal ganglion cell complex from thinning after optic nerve crush. These findings reveal a neuroprotective effect of knocking down Maf1 on RGC survival after injury and provide a potential therapeutic strategy for traumatic optic neuropathy.
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Affiliation(s)
- Di Chen
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201999, China
| | - Yi-Yu Sun
- Southern Medical University Affiliated Fengxian Hospital, Shanghai 201499, China
| | - Lai-Yang Zhou
- Southern Medical University Affiliated Fengxian Hospital, Shanghai 201499, China
| | - Shuo Yang
- Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Fei-Yang Hong
- Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xian-Dong Liu
- Shanghai Ruijin hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200020, China
| | - Zhao-Liang Sun
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201999, China
| | - Ju Huang
- Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Dong-Fu Feng
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201999, China; Southern Medical University Affiliated Fengxian Hospital, Shanghai 201499, China.
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10
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Kulaberoglu Y, Malik Y, Borland G, Selman C, Alic N, Tullet JMA. RNA Polymerase III, Ageing and Longevity. Front Genet 2021; 12:705122. [PMID: 34295356 PMCID: PMC8290157 DOI: 10.3389/fgene.2021.705122] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
Transcription in eukaryotic cells is performed by three RNA polymerases. RNA polymerase I synthesises most rRNAs, whilst RNA polymerase II transcribes all mRNAs and many non-coding RNAs. The largest of the three polymerases is RNA polymerase III (Pol III) which transcribes a variety of short non-coding RNAs including tRNAs and the 5S rRNA, in addition to other small RNAs such as snRNAs, snoRNAs, SINEs, 7SL RNA, Y RNA, and U6 spilceosomal RNA. Pol III-mediated transcription is highly dynamic and regulated in response to changes in cell growth, cell proliferation and stress. Pol III-generated transcripts are involved in a wide variety of cellular processes, including translation, genome and transcriptome regulation and RNA processing, with Pol III dys-regulation implicated in diseases including leukodystrophy, Alzheimer's, Fragile X-syndrome and various cancers. More recently, Pol III was identified as an evolutionarily conserved determinant of organismal lifespan acting downstream of mTORC1. Pol III inhibition extends lifespan in yeast, worms and flies, and in worms and flies acts from the intestine and intestinal stem cells respectively to achieve this. Intriguingly, Pol III activation achieved through impairment of its master repressor, Maf1, has also been shown to promote longevity in model organisms, including mice. In this review we introduce the Pol III transcription apparatus and review the current understanding of RNA Pol III's role in ageing and lifespan in different model organisms. We then discuss the potential of Pol III as a therapeutic target to improve age-related health in humans.
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Affiliation(s)
- Yavuz Kulaberoglu
- Department of Genetics Evolution and Environment, Institute of Healthy Ageing, University College London, London, United Kingdom
| | - Yasir Malik
- Faculty of Natural Sciences, University of Kent, Canterbury, United Kingdom
| | - Gillian Borland
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Nazif Alic
- Department of Genetics Evolution and Environment, Institute of Healthy Ageing, University College London, London, United Kingdom.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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dos Santos FRC, Guardia GDA, dos Santos FF, Ohara D, Galante PAF. Reboot: a straightforward approach to identify genes and splicing isoforms associated with cancer patient prognosis. NAR Cancer 2021; 3:zcab024. [PMID: 34316711 PMCID: PMC8210018 DOI: 10.1093/narcan/zcab024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/26/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022] Open
Abstract
Nowadays, the massive amount of data generated by modern sequencing technologies provides an unprecedented opportunity to find genes associated with cancer patient prognosis, connecting basic and translational research. However, treating high dimensionality of gene expression data and integrating it with clinical variables are major challenges to perform these analyses. Here, we present Reboot, an integrative approach to find and validate genes and transcripts (splicing isoforms) associated with cancer patient prognosis from high dimensional expression datasets. Reboot innovates by using a multivariate strategy with penalized Cox regression (LASSO method) combined with a bootstrap approach, in addition to statistical tests and plots to support the findings. Applying Reboot on data from 154 glioblastoma patients, we identified a three-gene signature (IKBIP, OSMR, PODNL1) whose increased derived risk score was significantly associated with worse patients' prognosis. Similarly, Reboot was able to find a seven-splicing isoforms signature related to worse overall survival in 177 pancreatic adenocarcinoma patients with elevated risk scores after uni- and multivariate analyses. In summary, Reboot is an efficient, intuitive and straightforward way of finding genes or splicing isoforms signatures relevant to patient prognosis, which can democratize this kind of analysis and shed light on still under-investigated cancer-related genes and splicing isoforms.
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Affiliation(s)
- Felipe R C dos Santos
- Centro de Oncologia Molecular, Hospital Sirio-Libanes, Sao Paulo, SP 01308-060, Brazil
- Programa Interunidades em Bioinformatica, Universidade de São Paulo, Sao Paulo, SP 05508-090, Brazil
| | - Gabriela D A Guardia
- Centro de Oncologia Molecular, Hospital Sirio-Libanes, Sao Paulo, SP 01308-060, Brazil
| | - Filipe F dos Santos
- Centro de Oncologia Molecular, Hospital Sirio-Libanes, Sao Paulo, SP 01308-060, Brazil
- Departamento de Bioquimica, Universidade de Sao Paulo, SP 05508-000, Brazil
| | - Daniel T Ohara
- Centro de Oncologia Molecular, Hospital Sirio-Libanes, Sao Paulo, SP 01308-060, Brazil
| | - Pedro A F Galante
- Centro de Oncologia Molecular, Hospital Sirio-Libanes, Sao Paulo, SP 01308-060, Brazil
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12
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Roles of tRNA metabolism in aging and lifespan. Cell Death Dis 2021; 12:548. [PMID: 34039958 PMCID: PMC8154886 DOI: 10.1038/s41419-021-03838-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/17/2022]
Abstract
Transfer RNAs (tRNAs) mainly function as adapter molecules that decode messenger RNAs (mRNAs) during protein translation by delivering amino acids to the ribosome. Traditionally, tRNAs are considered as housekeepers without additional functions. Nevertheless, it has become apparent from biological research that tRNAs are involved in various physiological and pathological processes. Aging is a form of gradual decline in physiological function that ultimately leads to increased vulnerability to multiple chronic diseases and death. Interestingly, tRNA metabolism is closely associated with aging and lifespan. In this review, we summarize the emerging roles of tRNA-associated metabolism, such as tRNA transcription, tRNA molecules, tRNA modifications, tRNA aminoacylation, and tRNA derivatives, in aging and lifespan, aiming to provide new ideas for developing therapeutics and ultimately extending lifespan in humans.
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13
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Wang M, Liu X, Wu Y, Wang Y, Cui J, Sun J, Bai Y, Lang MF. ΜicroRNA-122 protects against ischemic stroke by targeting Maf1. Exp Ther Med 2021; 21:616. [PMID: 33936273 DOI: 10.3892/etm.2021.10048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 09/11/2020] [Indexed: 11/06/2022] Open
Abstract
The protection of brain tissue against damage and the reduction of infarct size is crucial for improving patient prognosis following ischemic stroke. Therefore, the present study aimed to investigate the regulatory effect of microRNA (miR)-122 and its target gene repressor of RNA polymerase III transcription MAF1 homolog (Maf1) on the infarct area in ischemic stroke. Reverse transcription-quantitative PCR (RT-qPCR) was performed to determine miR-122 expression levels in an ischemic stroke [middle cerebral artery occlusion (MCAO)] mouse model. Nissl staining was conducted to measure the infarct area of the MCAO mouse model. Moreover, RT-qPCR was performed to investigate the relationship between the expression of Maf1 and miR-122 in the MCAO mouse model. Dual-luciferase reporter assay in vitro and miR-122 mimic or inhibitor treatment in vivo were conducted to verify that miR-122 targeted and inhibited Maf1 expression. The results suggested that miR-122 was upregulated in the brain tissue of MCAO model mice. miR-122 overexpression effectively reduced the size of the infarct area in comparison with a control and miR-122 knockdown in brain tissue resulted in the opposite effect. Moreover, Maf1 was confirmed to be a direct target of miR-122. The results of a dual-luciferase reporter assay indicated that miR-122 bound to the 3'-untranslated region of Maf1. Maf1 expression decreased after stroke model induction in comparison with that in sham animals, and Maf1 expression was negatively associated with the expression of miR-122. In addition, miR-122 knockdown increased Maf1 expression levels, whereas miR-122 overexpression decreased Maf1 expression levels in comparison with a control. In conclusion, the results suggested that miR-122 improved the outcome of acute ischemic stroke by reducing the expression of Maf1.
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Affiliation(s)
- Mengmeng Wang
- Department of Neurology, Affiliated Xinhua Hospital of Dalian University, Dalian, Liaoning 116021, P.R. China
| | - Xiaoman Liu
- Department of Neurology, Affiliated Xinhua Hospital of Dalian University, Dalian, Liaoning 116021, P.R. China
| | - Yu Wu
- Medical College, Institute of Microanalysis, Dalian University, Dalian, Liaoning 116622, P.R. China
| | - Yi Wang
- Department of Neurology, Affiliated Xinhua Hospital of Dalian University, Dalian, Liaoning 116021, P.R. China
| | - Jiahui Cui
- Department of Neurology, Affiliated Xinhua Hospital of Dalian University, Dalian, Liaoning 116021, P.R. China
| | - Jing Sun
- College of Environmental and Chemical Engineering, Institute of Microanalysis, Dalian University, Dalian, Liaoning 116622, P.R. China
| | - Ying Bai
- Department of Neurology, Affiliated Xinhua Hospital of Dalian University, Dalian, Liaoning 116021, P.R. China
| | - Ming-Fei Lang
- Medical College, Institute of Microanalysis, Dalian University, Dalian, Liaoning 116622, P.R. China
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14
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Lai C, Zhang J, Tan Z, Shen LF, Zhou RR, Zhang YY. Maf1 suppression of ATF5-dependent mitochondrial unfolded protein response contributes to rapamycin-induced radio-sensitivity in lung cancer cell line A549. Aging (Albany NY) 2021; 13:7300-7313. [PMID: 33640883 PMCID: PMC7993702 DOI: 10.18632/aging.202584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
mTOR is well known to promote tumor growth but its roles in enhancing chemotherapy and radiotherapy have not been well studied. mTOR inhibition by rapamycin can sensitize cancer cells to radiotherapy. Here we show that Maf1 is required for rapamycin to increase radio-sensitivity in A549 lung cancer cells. In response to ionizing radiation (IR), Maf1 is inhibited by Akt-dependent re-phosphorylation, which activates mitochondrial unfolded protein response (UPRmt) through ATF5. Rapamycin suppresses IR-induced Maf1 re-phosphorylation and UPRmt activation in A549 cells, resulting in increased sensitivity to IR-mediated cytotoxicity. Consistently, Maf1 knockdown activates ATF5-transcription of mtHSP70 and HSP60, enhances mitochondrial membrane potential, reduces intracellular ROS levels and dampens rapamycin's effect on increasing IR-mediated cytotoxicity. In addition, Maf1 overexpression suppresses ethidium bromide-induced UPRmt and enhances IR-mediated cytotoxicity. Supporting our cell-based studies, elevated expression of UPRmt makers (mtHSP70 and HSP60) are associated with poor prognosis in patients with lung adenocarcinoma (LAUD). Together, our study reveals a novel role of Maf1-UPRmt axis in mediating rapamycin's enhancing effect on IR sensitivity in A549 lung cancer cells.
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Affiliation(s)
- Chen Lai
- Department of General Surgery, Xiangya Hospital of Central South University, Changsha 410008, Hunan, China.,Hunan Key Laboratory of Precise Diagnosis and Treatment of Gastrointestinal Tumor, Changsha 410008, Hunan, China
| | - Jing Zhang
- Department of Oncology, Xiangya Hospital of Central South University, Changsha 410008, Hunan, China.,Xiangya Lung Cancer Center, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Zhaohua Tan
- Department of Oncology, Xiangya Hospital of Central South University, Changsha 410008, Hunan, China.,Xiangya Lung Cancer Center, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Liang F Shen
- Department of Oncology, Xiangya Hospital of Central South University, Changsha 410008, Hunan, China
| | - Rong R Zhou
- Department of Oncology, Xiangya Hospital of Central South University, Changsha 410008, Hunan, China.,Xiangya Lung Cancer Center, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Ying Y Zhang
- Department of Oncology, Xiangya Hospital of Central South University, Changsha 410008, Hunan, China.,Xiangya Lung Cancer Center, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
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15
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Boulanger M, Chakraborty M, Tempé D, Piechaczyk M, Bossis G. SUMO and Transcriptional Regulation: The Lessons of Large-Scale Proteomic, Modifomic and Genomic Studies. Molecules 2021; 26:molecules26040828. [PMID: 33562565 PMCID: PMC7915335 DOI: 10.3390/molecules26040828] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
One major role of the eukaryotic peptidic post-translational modifier SUMO in the cell is transcriptional control. This occurs via modification of virtually all classes of transcriptional actors, which include transcription factors, transcriptional coregulators, diverse chromatin components, as well as Pol I-, Pol II- and Pol III transcriptional machineries and their regulators. For many years, the role of SUMOylation has essentially been studied on individual proteins, or small groups of proteins, principally dealing with Pol II-mediated transcription. This provided only a fragmentary view of how SUMOylation controls transcription. The recent advent of large-scale proteomic, modifomic and genomic studies has however considerably refined our perception of the part played by SUMO in gene expression control. We review here these developments and the new concepts they are at the origin of, together with the limitations of our knowledge. How they illuminate the SUMO-dependent transcriptional mechanisms that have been characterized thus far and how they impact our view of SUMO-dependent chromatin organization are also considered.
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Affiliation(s)
- Mathias Boulanger
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France; (M.B.); (M.C.); (D.T.)
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Mehuli Chakraborty
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France; (M.B.); (M.C.); (D.T.)
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Denis Tempé
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France; (M.B.); (M.C.); (D.T.)
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Marc Piechaczyk
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France; (M.B.); (M.C.); (D.T.)
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
- Correspondence: (M.P.); (G.B.)
| | - Guillaume Bossis
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France; (M.B.); (M.C.); (D.T.)
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
- Correspondence: (M.P.); (G.B.)
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16
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Molecular Characterization of Paralichthys olivaceus MAF1 and Its Potential Role as an Anti-Viral Hemorrhagic Septicaemia Virus Factor in Hirame Natural Embryo Cells. Int J Mol Sci 2021; 22:ijms22031353. [PMID: 33572970 PMCID: PMC7866426 DOI: 10.3390/ijms22031353] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/18/2022] Open
Abstract
MAF1 is a global suppressor of RNA polymerase III-dependent transcription, and is conserved from yeast to human. Growing evidence supports the involvement of MAF1 in the immune response of mammals, but its biological functions in fish are unknown. We isolated and characterized Maf1 from the olive flounder Paralichthys olivaceus (PoMaf1). The coding region of PoMaf1 comprised 738 bp encoding a 245-amino-acid protein. The deduced PoMAF1 amino acid sequence shared features with those of MAF1 orthologues from vertebrates. PoMaf1 mRNA was detected in all tissues examined, and the levels were highest in eye and muscle tissue. The PoMaf1 mRNA level increased during early development. In addition, the PoMaf1 transcript level decreased during viral hemorrhagic septicemia virus (VHSV) infection of flounder hirame natural embryo (HINAE) cells. To investigate the role of PoMaf1 in VHSV infection, single-cell-derived PoMaf1 knockout HINAE cells were generated using the clustered regularly interspaced short palindromic repeats/CRISPR-associated-9 (CRISPR/Cas9) system, and cell clones with complete disruption of PoMaf1 were selected. PoMaf1 disruption increased the VHSV glycoprotein (G) mRNA levels during VHSV infection of HINAE cells, implicating PoMAF1 in the immune response to VSHV infection. To our knowledge, this is the first study to characterize fish Maf1, which may play a role in the response to viral infection.
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17
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Noguchi C, Wang L, Shetty M, Mell JC, Sell C, Noguchi E. Maf1 limits RNA polymerase III-directed transcription to preserve genomic integrity and extend lifespan. Cell Cycle 2021; 20:247-255. [PMID: 33475456 DOI: 10.1080/15384101.2021.1874697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A key to longevity assurance is the nutrient-sensing mTOR pathway. Inhibition of mTOR extends lifespan in a variety of organisms. However, the downstream effectors of the mTOR pathway for lifespan regulation are elusive. In a recent report, we described the role of Maf1 as a critical lifespan regulator downstream of the mTOR pathway in fission yeast. Maf1 is the master negative regulator of RNA polymerase III-directed transcription (e.g. tRNAs and 5S rRNAs) and is regulated by mTOR-mediated phosphorylation. We demonstrated that Maf1 is required for lifespan extension under calorie restriction or when mTOR is inhibited. We also showed that Maf1 prevents DNA damage at tRNA genes, which appears to contribute to lifespan maintenance by Maf1. Here we highlight these observations and present additional results to discuss the role of the mTOR-Maf1-Pol III axis in promoting genomic integrity in the face of DNA replication-transcription conflicts in order to maintain normal lifespan.
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Affiliation(s)
- Chiaki Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, PA, USA
| | - Lucy Wang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, PA, USA
| | - Mihir Shetty
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, PA, USA
| | - Joshua Chang Mell
- Department of Microbiology & Immunology, Centers for Genomics Sciences, Drexel University College of Medicine , Philadelphia, PA, USA
| | - Christian Sell
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, PA, USA
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, PA, USA
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18
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Chen S, Tang C, Ding H, Wang Z, Liu X, Chai Y, Jiang W, Han Y, Zeng H. Maf1 Ameliorates Sepsis-Associated Encephalopathy by Suppressing the NF- kB/NLRP3 Inflammasome Signaling Pathway. Front Immunol 2020; 11:594071. [PMID: 33424842 PMCID: PMC7785707 DOI: 10.3389/fimmu.2020.594071] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/17/2020] [Indexed: 12/13/2022] Open
Abstract
Background The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome has been identified as an important mediator of blood–brain-barrier disruption in sepsis-associated encephalopathy (SAE). However, no information is available concerning the critical upstream regulators of SAE. Methods Lipopolysaccharide (LPS) was used to establish an in vitro model of blood–brain barrier (BBB) disruption and an in vivo model of SAE. Disruption of BBB integrity was assessed by measuring the expression levels of tight-junction proteins. NLRP3 inflammasome activation, pro-inflammatory cytokines levels, and neuroapoptosis were measured using biochemical assays. Finally, the FITC-dextran Transwell assay and Evan’s blue dye assay were used to assess the effect of Maf1 on LPS-induced endothelial permeability in vitro and in vivo. Results We found that Maf1 significantly suppressed the brain inflammatory response and neuroapoptosis induced by LPS in vivo and in vitro. Notably, Maf1 downregulated activation of the NF-κB/p65-induced NLRP3 inflammasome and the expression of pro-inflammatory cytokines. In addition, we found that Maf1 and p65 directly bound to the NLRP3 gene promoter region and competitively regulated the function of NLRP3 in inflammations. Moreover, overexpression of NLRP3 reversed the effects of p65 on BBB integrity, apoptosis, and inflammation in response to LPS. Our study revealed novel role for Maf1 in regulating NF-κB-mediated inflammasome formation, which plays a prominent role in SAE. Conclusions Regulation of Maf1 might be a therapeutic strategy for SAE and other neurodegenerative diseases associated with inflammation.
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Affiliation(s)
- Shenglong Chen
- Department of Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Chaogang Tang
- Department of Cerebrovascular Disease, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, China
| | - Hongguang Ding
- Department of Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhonghua Wang
- Department of Gerontological Critical Care Medicine, Guangdong Provincial People's Hospital/Guangdong Academy of Medical Sciences/Guangdong Provincial Geriatrics Institute, Guangzhou, China
| | - Xinqiang Liu
- Department of Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yunfei Chai
- Anesthesiology Department of Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wenqiang Jiang
- Department of Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yongli Han
- Department of Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Hongke Zeng
- Department of Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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19
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Otsubo Y, Kamada Y, Yamashita A. Novel Links between TORC1 and Traditional Non-Coding RNA, tRNA. Genes (Basel) 2020; 11:E956. [PMID: 32825021 PMCID: PMC7563549 DOI: 10.3390/genes11090956] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022] Open
Abstract
Target of rapamycin (TOR) is a serine/threonine kinase that modulates cell growth and metabolism in response to environmental changes. Transfer RNA (tRNA) is an abundant and ubiquitous small non-coding RNA that is essential in the translation of mRNAs. Beyond its canonical role, it has been revealed that tRNAs have more diverse functions. TOR complex 1 (TORC1), which is one of the two TOR complexes, regulates tRNA synthesis by controlling RNA polymerase III. In addition to tRNA synthesis regulation, recent studies have revealed hidden connections between TORC1 and tRNA, which are both essential players in eukaryotic cellular activities. Here, we review the accumulating findings on the regulatory links between TORC1 and tRNA-particularly those links in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe.
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Affiliation(s)
- Yoko Otsubo
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Yoshiaki Kamada
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Akira Yamashita
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
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20
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Maf1 regulates dendritic morphogenesis and influences learning and memory. Cell Death Dis 2020; 11:606. [PMID: 32732865 PMCID: PMC7393169 DOI: 10.1038/s41419-020-02809-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 07/12/2020] [Accepted: 07/14/2020] [Indexed: 12/24/2022]
Abstract
Maf1, a general transcriptional regulator and mTOR downstream effector, is highly expressed in the hippocampus and cortex, but the function of Maf1 in neurons is not well elucidated. Here, we first demonstrate that Maf1 plays a central role in the inhibition of dendritic morphogenesis and the growth of dendritic spines both in vitro and in vivo. Furthermore, Maf1 downregulation paradoxically leads to activation of AKT-mTOR signaling, which is mediated by decreased PTEN expression. Moreover, we confirmed that Maf1 could regulate the activity of PTEN promoter by luciferase reporter assay, and proved that Maf1 could bind to the promoter of PTEN by ChIP-PCR experiment. We also demonstrate that expression of Maf1 in the hippocampus affects learning and memory in mice. Taken together, we show for the first time that Maf1 inhibits dendritic morphogenesis and the growth of dendritic spines through AKT-mTOR signaling by increasing PTEN expression.
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21
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Shetty M, Noguchi C, Wilson S, Martinez E, Shiozaki K, Sell C, Mell JC, Noguchi E. Maf1-dependent transcriptional regulation of tRNAs prevents genomic instability and is associated with extended lifespan. Aging Cell 2020; 19:e13068. [PMID: 31833215 PMCID: PMC6996946 DOI: 10.1111/acel.13068] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/18/2022] Open
Abstract
Maf1 is the master repressor of RNA polymerase III responsible for transcription of tRNAs and 5S rRNAs. Maf1 is negatively regulated via phosphorylation by the mTOR pathway, which governs protein synthesis, growth control, and lifespan regulation in response to nutrient availability. Inhibiting the mTOR pathway extends lifespan in various organisms. However, the downstream effectors for the regulation of cell homeostasis that are critical to lifespan extension remain elusive. Here we show that fission yeast Maf1 is required for lifespan extension. Maf1's function in tRNA repression is inhibited by mTOR-dependent phosphorylation, whereas Maf1 is activated via dephosphorylation by protein phosphatase complexes, PP4 and PP2A. Mutational analysis reveals that Maf1 phosphorylation status influences lifespan, which is correlated with elevated tRNA and protein synthesis levels in maf1∆ cells. However, mTOR downregulation, which negates protein synthesis, fails to rescue the short lifespan of maf1∆ cells, suggesting that elevated protein synthesis is not a cause of lifespan shortening in maf1∆ cells. Interestingly, maf1∆ cells accumulate DNA damage represented by formation of Rad52 DNA damage foci and Rad52 recruitment at tRNA genes. Loss of the Rad52 DNA repair protein further exacerbates the shortened lifespan of maf1∆ cells. Strikingly, PP4 deletion alleviates DNA damage and rescues the short lifespan of maf1∆ cells even though tRNA synthesis is increased in this condition, suggesting that elevated DNA damage is the major cause of lifespan shortening in maf1∆ cells. We propose that Maf1-dependent inhibition of tRNA synthesis controls fission yeast lifespan by preventing genomic instability that arises at tRNA genes.
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Affiliation(s)
- Mihir Shetty
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Chiaki Noguchi
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Sydney Wilson
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Esteban Martinez
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
- Present address:
Fox Chase Cancer CenterPhiladelphiaPAUSA
| | - Kazuhiro Shiozaki
- Division of Biological ScienceNara Institute of Science and TechnologyIkomaJapan
- Department of Microbiology and Molecular GeneticsUniversity of CaliforniaDavisCAUSA
| | - Christian Sell
- Department of PathologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Joshua Chang Mell
- Department of Microbiology and ImmunologyCenters for Genomics SciencesDrexel University College of MedicinePhiladelphiaPAUSA
| | - Eishi Noguchi
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
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22
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The Mammalian Target of Rapamycin–70-kDa Ribosomal Protein S6 Kinase Axis Inhibits the Biological Function of Tongue Squamous Cell Carcinoma. J Oral Maxillofac Surg 2019; 77:1928-1940. [DOI: 10.1016/j.joms.2018.09.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 09/12/2018] [Accepted: 09/12/2018] [Indexed: 01/19/2023]
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23
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Asghar F, Yan H, Jiang L. The putative transcription factor CaMaf1 controls the sensitivity to lithium and rapamycin and represses RNA polymerase III transcription in Candida albicans. FEMS Yeast Res 2018; 18:5047891. [PMID: 29982370 DOI: 10.1093/femsyr/foy068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 06/23/2018] [Indexed: 12/19/2022] Open
Abstract
Maf1 is a repressor of RNA polymerase (Pol) III transcription for tRNA. Nutrient deprivation and environmental stress repress Pol III transcription through Maf1 in Saccharomyces cerevisiae. The sole Candida albicans homolog CaMaf1 is a protein of 380 amino acids with conserved domains and motifs of the eukaryotic Maf1 family. Here, we show that C. albicans cells lacking CaMAF1 show elevated levels of tRNA. Deletion of CaMAF1 increases the sensitivity of C. albicans cells to lithium cation and SDS as well as tolerance to rapamycin and azole. In addition, deletion of CaMAF1 reduces the level of filamentation and alters the surface morphology of colonies. CaMaf1 is localized in the nucleus of log-phase growing cells. However, a dynamic change of subcellular localization of CaMaf1 exists during serum-induced morphological transition, with CaMaf1 being localized in the nuclei of cells with germ tubes and short filaments but outside of the nuclei of cells with long filaments. In addition, CaMaf1 is required for rapamycin-induced repression of CaERG20, encoding the farnesyl pyrophosphate synthetase involved in ergosterol biosynthesis. Therefore, CaMaf1 plays a role as a general repressor of Pol III transcription in C. albicans.
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Affiliation(s)
- Faiza Asghar
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, School of Agricultural Engineering and Food Science, Shandong University of Technology, 266 XiCunXi Road, Zibo 255000, China
| | - Hongbo Yan
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, School of Agricultural Engineering and Food Science, Shandong University of Technology, 266 XiCunXi Road, Zibo 255000, China
| | - Linghuo Jiang
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, School of Agricultural Engineering and Food Science, Shandong University of Technology, 266 XiCunXi Road, Zibo 255000, China
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