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Njeim R, Merscher S, Fornoni A. Mechanisms and implications of podocyte autophagy in chronic kidney disease. Am J Physiol Renal Physiol 2024; 326:F877-F893. [PMID: 38601984 DOI: 10.1152/ajprenal.00415.2023] [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: 12/22/2023] [Revised: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 04/12/2024] Open
Abstract
Autophagy is a protective mechanism through which cells degrade and recycle proteins and organelles to maintain cellular homeostasis and integrity. An accumulating body of evidence underscores the significant impact of dysregulated autophagy on podocyte injury in chronic kidney disease (CKD). In this review, we provide a comprehensive overview of the diverse types of autophagy and their regulation in cellular homeostasis, with a specific emphasis on podocytes. Furthermore, we discuss recent findings that focus on the functional role of different types of autophagy during podocyte injury in chronic kidney disease. The intricate interplay between different types of autophagy and podocyte health requires further research, which is critical for understanding the pathogenesis of CKD and developing targeted therapeutic interventions.
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Affiliation(s)
- Rachel Njeim
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, United States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Sandra Merscher
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, United States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, United States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, Florida, United States
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2
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Jhanwar-Uniyal M, Zeller SL, Spirollari E, Das M, Hanft SJ, Gandhi CD. Discrete Mechanistic Target of Rapamycin Signaling Pathways, Stem Cells, and Therapeutic Targets. Cells 2024; 13:409. [PMID: 38474373 DOI: 10.3390/cells13050409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that functions via its discrete binding partners to form two multiprotein complexes, mTOR complex 1 and 2 (mTORC1 and mTORC2). Rapamycin-sensitive mTORC1, which regulates protein synthesis and cell growth, is tightly controlled by PI3K/Akt and is nutrient-/growth factor-sensitive. In the brain, mTORC1 is also sensitive to neurotransmitter signaling. mTORC2, which is modulated by growth factor signaling, is associated with ribosomes and is insensitive to rapamycin. mTOR regulates stem cell and cancer stem cell characteristics. Aberrant Akt/mTOR activation is involved in multistep tumorigenesis in a variety of cancers, thereby suggesting that the inhibition of mTOR may have therapeutic potential. Rapamycin and its analogues, known as rapalogues, suppress mTOR activity through an allosteric mechanism that only suppresses mTORC1, albeit incompletely. ATP-catalytic binding site inhibitors are designed to inhibit both complexes. This review describes the regulation of mTOR and the targeting of its complexes in the treatment of cancers, such as glioblastoma, and their stem cells.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Sabrina L Zeller
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Eris Spirollari
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Mohan Das
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Simon J Hanft
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
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3
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Ali Y, Gomez-Sanchez CE, Plonczynski M, Naray-Fejes-Toth A, Fejes-Toth G, Gomez-Sanchez EP. mTOR Regulates Mineralocorticoid Receptor Transcriptional Activity by ULK1-Dependent and -Independent Mechanisms. Endocrinology 2024; 165:bqae015. [PMID: 38325289 PMCID: PMC10887451 DOI: 10.1210/endocr/bqae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/31/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
The mineralocorticoid receptor (MR) is a transcription factor for genes mediating diverse, cell-specific functions, including trophic effects as well as promoting fluid/electrolyte homeostasis. It was reported that in intercalated cells, phosphorylation of the MR at serine 843 (S843) by Unc-51-like kinase (ULK1) inhibits MR activation and that phosphorylation of ULK1 by mechanistic target of rapamycin (mTOR) inactivates ULK1, and thereby prevents MR inactivation. We extended these findings with studies in M1 mouse cortical collecting duct cells stably expressing the rat MR and a reporter gene. Pharmacological inhibition of ULK1 dose-dependently increased ligand-induced MR transactivation, while ULK1 activation had no effect. Pharmacological inhibition of mTOR and CRISPR/gRNA gene knockdown of rapamycin-sensitive adapter protein of mTOR (Raptor) or rapamycin-insensitive companion of mTOR (Rictor) decreased phosphorylated ULK1 and ligand-induced activation of the MR reporter gene, as well as transcription of endogenous MR-target genes. As predicted, ULK1 inhibition had no effect on aldosterone-mediated transcription in M1 cells with the mutated MR-S843A (alanine cannot be phosphorylated). In contrast, mTOR inhibition dose-dependently decreased transcription in the MR-S843A cells, though not as completely as in cells with the wild-type MR-S843. mTOR, Raptor, and Rictor coprecipitated with the MR and addition of aldosterone increased their phosphorylated, active state. These results suggest that mTOR significantly regulates MR activity in at least 2 ways: by suppressing MR inactivation by ULK1, and by a yet ill-defined mechanism that involves direct association with MR. They also provide new insights into the diverse functions of ULK1 and mTOR, 2 key enzymes that monitor the cell's energy status.
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Affiliation(s)
- Yusuf Ali
- Research Service, G. V. (Sonny) Montgomery VA Medical Center, Jackson, MS 39216, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Celso E Gomez-Sanchez
- Research Service, G. V. (Sonny) Montgomery VA Medical Center, Jackson, MS 39216, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Maria Plonczynski
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | | | - Geza Fejes-Toth
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03755, USA
| | - Elise P Gomez-Sanchez
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
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VenkataKrishna LM, Balasubramaniam B, Sushmitha TJ, Ravichandiran V, Balamurugan K. Cronobacter sakazakii infection implicates multifaceted neuro-immune regulatory pathways of Caenorhabditis elegans. Mol Omics 2024; 20:48-63. [PMID: 37818754 DOI: 10.1039/d3mo00167a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
The neural pathways of Caenorhabditis elegans play a crucial role in regulating host immunity and inflammation during pathogenic infections. To understand the major neuro-immune signaling pathways, this study aimed to identify the key regulatory proteins in the host C. elegans during C. sakazakii infection. We used high-throughput label-free quantitative proteomics and identified 69 differentially expressed proteins. KEGG analysis revealed that C. sakazakii elicited host immune signaling cascades primarily including mTOR signaling, axon regeneration, metabolic pathways (let-363 and acox-1.4), calcium signaling (mlck-1), and longevity regulating pathways (ddl-2), respectively. The abrogation in functional loss of mTOR-associated players deciphered that C. sakazakii infection negatively regulated the lifespan of mutant worms (akt-1, let-363 and dlk-1), including physiological aberrations, such as reduced pharyngeal pumping and egg production. Additionally, the candidate pathway proteins were validated by transcriptional profiling of their corresponding genes. Furthermore, immunoblotting showed the downregulation of mTORC2/SGK-1 during the later hours of pathogen exposure. Overall, our findings profoundly provide an understanding of the specificity of proteome imbalance in affecting neuro-immune regulations during C. sakazakii infection.
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Affiliation(s)
| | | | - T J Sushmitha
- Department of Biotechnology, Science Campus, Alagappa University, Karaikudi, Tamil Nadu, India.
| | - V Ravichandiran
- National Institute of Pharmaceutical Education and Research, Kolkata, West Bengal, India
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5
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Honda D, Okumura M, Chihara T. Crosstalk between the mTOR and Hippo pathways. Dev Growth Differ 2023; 65:337-347. [PMID: 37209252 DOI: 10.1111/dgd.12867] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/27/2023] [Accepted: 05/16/2023] [Indexed: 05/22/2023]
Abstract
Cell behavior changes in response to multiple stimuli, such as growth factors, nutrients, and cell density. The mechanistic target of the rapamycin (mTOR) pathway is activated by growth factors and nutrient stimuli to regulate cell growth and autophagy, whereas the Hippo pathway has negative effects on cell proliferation and tissue growth in response to cell density, DNA damage, and hormonal signals. These two signaling pathways must be precisely regulated and integrated for proper cell behavior. This integrative mechanism is not completely understood; nevertheless, recent studies have suggested that components of the mTOR and Hippo pathways interact with each other. Herein, as per contemporary knowledge, we review the molecular mechanisms of the interaction between the mTOR and Hippo pathways in mammals and Drosophila. Moreover, we discuss the advantage of this interaction in terms of tissue growth and nutrient consumption.
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Affiliation(s)
- Daichi Honda
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Misako Okumura
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Program of Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Takahiro Chihara
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Program of Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
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6
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Ali Y, Gomez-Sanchez EP, Gomez-Sanchez CE. Mammalian Target of Rapamycin Inhibition Decreases Angiotensin II-Induced Steroidogenesis in HAC15 Human Adrenocortical Carcinoma Cells. Endocrinology 2022; 164:bqac185. [PMID: 36320101 PMCID: PMC9923797 DOI: 10.1210/endocr/bqac185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Indexed: 11/11/2022]
Abstract
BACKGROUND Mammalian target of rapamycin (mTOR) inhibitors suppress adrenal cortical carcinoma cell proliferation and cortisol production; the relationship between mTOR and aldosterone production has not been examined. METHODS HAC15 cells were incubated with an mTOR activator and several inhibitors including AZD8055 (AZD) in the presence and absence of angiotensin II (AngII). The expression of rapamycin-sensitive adapter protein of mTOR (Raptor) and rapamycin-insensitive companion of mTOR (Rictor), adaptor proteins of mTOR complex 1 and 2, respectively, were studied in the HAC15 cells and deleted by CRISPR/gRNA. RESULTS The mTOR inhibitors decreased aldosterone induced by AngII. Inhibition of mTOR by AZD significantly suppressed AngII-induced aldosterone and cortisol formation in a dose-dependent manner, whereas the mTOR activator MHY had no effect. AZD did not alter forskolin-induced aldosterone production showing that it is specific to the AngII signaling pathway. AngII-mediated ERK and mTOR activation were suppressed by AZD, along with a concomitant dose-dependent reduction of AngII-induced steroidogenic enzymes including steroidogenic acute regulatory protein, 3β-hydroxysteroid dehydrogenase-type 2, CYP17A1, and aldosterone synthase protein. Furthermore, mTOR components ribosomal protein S6 kinase (P70S6K) and protein kinase B phosphorylation levels were decreased by AZD. As mTOR exerts its main effects by forming complexes with adaptor proteins Raptor and Rictor, the roles of these individual complexes were studied. We found an increase in the phosphorylation of Raptor and Rictor by AngII and that their CRISPR/gRNA-mediated knockdown significantly attenuated AngII-induced aldosterone and cortisol production. CONCLUSION mTOR signaling has a critical role in transducing the AngII signal initiating aldosterone and cortisol synthesis in HAC15 cells and that inhibition of mTOR could be a therapeutic option for conditions associated with excessive renin-angiotensin system-mediated steroid synthesis.
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Affiliation(s)
- Yusuf Ali
- G. V. (Sonny) Montgomery, VA Medical Center, Jackson, MS, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Elise P Gomez-Sanchez
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Celso E Gomez-Sanchez
- G. V. (Sonny) Montgomery, VA Medical Center, Jackson, MS, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
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7
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Lasagni Vitar R, Triani F, Barbariga M, Fonteyne P, Rama P, Ferrari G. Substance P/neurokinin-1 receptor pathway blockade ameliorates limbal stem cell deficiency by modulating mTOR pathway and preventing cell senescence. Stem Cell Reports 2022; 17:849-863. [PMID: 35334220 PMCID: PMC9023781 DOI: 10.1016/j.stemcr.2022.02.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 11/01/2022] Open
Abstract
Severe ocular surface diseases can lead to limbal stem cell deficiency (LSCD), which is accompanied by defective healing. We aimed to evaluate the role of the substance P (SP)/neurokinin-1 receptor (NK1R) pathway in corneal epithelium wound healing in a pre-clinical model of LSCD. SP ablation or NK1R blockade significantly increased epithelial wound healing (p < 0.001) and corneal transparency (p < 0.001), compared with wild type (WT). In addition, a reduced number of infiltrating goblet and conjunctival cells (p < 0.05) and increased number of epithelial stem cells (p < 0.01), which also expressed NK1R, was observed. The mammalian target of rapamycin (mTOR) pathway was significantly inhibited (p < 0.05) and expression of γH2AX was significantly reduced (p < 0.05) after SP ablation. These results suggest that excessive expression of SP is associated with LSCD and results in accelerated senescence and exhaustion of residual stem cells. Topical treatment with NK1R antagonist ameliorates clinical signs associated with LSCD and could be used as an adjuvant treatment in LSCD.
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Affiliation(s)
- Romina Lasagni Vitar
- Cornea and Ocular Surface Disease Unit, Eye Repair Lab, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Francesca Triani
- Cornea and Ocular Surface Disease Unit, Eye Repair Lab, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Marco Barbariga
- Cornea and Ocular Surface Disease Unit, Eye Repair Lab, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Philippe Fonteyne
- Cornea and Ocular Surface Disease Unit, Eye Repair Lab, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Paolo Rama
- Cornea and Ocular Surface Disease Unit, Eye Repair Lab, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Giulio Ferrari
- Cornea and Ocular Surface Disease Unit, Eye Repair Lab, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy.
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8
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Lojk J, Marc J. Roles of Non-Canonical Wnt Signalling Pathways in Bone Biology. Int J Mol Sci 2021; 22:10840. [PMID: 34639180 PMCID: PMC8509327 DOI: 10.3390/ijms221910840] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 01/15/2023] Open
Abstract
The Wnt signalling pathway is one of the central signalling pathways in bone development, homeostasis and regulation of bone mineral density. It consists of numerous Wnt ligands, receptors and co-receptors, which ensure tight spatiotemporal regulation of Wnt signalling pathway activity and thus tight regulation of bone tissue homeostasis. This enables maintenance of optimal mineral density, tissue healing and adaptation to changes in bone loading. While the role of the canonical/β-catenin Wnt signalling pathway in bone homeostasis is relatively well researched, Wnt ligands can also activate several non-canonical, β-catenin independent signalling pathways with important effects on bone tissue. In this review, we will provide a thorough overview of the current knowledge on different non-canonical Wnt signalling pathways involved in bone biology, focusing especially on the pathways that affect bone cell differentiation, maturation and function, processes involved in bone tissue structure regulation. We will describe the role of the two most known non-canonical pathways (Wnt/planar cell polarity pathways and Wnt/Ca2+ pathway), as well as other signalling pathways with a strong role in bone biology that communicate with the Wnt signalling pathway through non-canonical Wnt signalling. Our goal is to bring additional attention to these still not well researched but important pathways in the regulation of bone biology in the hope of prompting additional research in the area of non-canonical Wnt signalling pathways.
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Affiliation(s)
- Jasna Lojk
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia;
| | - Janja Marc
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia;
- University Clinical Center Ljubljana, Clinical Department of Clinical Chemistry and Biochemistry, 1000 Ljubljana, Slovenia
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9
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Amin AG, Jeong SW, Gillick JL, Sursal T, Murali R, Gandhi CD, Jhanwar-Uniyal M. Targeting the mTOR pathway using novel ATP‑competitive inhibitors, Torin1, Torin2 and XL388, in the treatment of glioblastoma. Int J Oncol 2021; 59:83. [PMID: 34523696 PMCID: PMC8448541 DOI: 10.3892/ijo.2021.5263] [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: 05/18/2020] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
Mechanistic target of rapamycin (mTOR), which functions via two multiprotein complexes termed mTORC1 and mTORC2, is positioned in the canonical phosphoinositide 3-kinase-related kinase (PI3K)/AKT (PI3K/AKT) pathways. These complexes exert their actions by regulating other important kinases, such as 40S ribosomal S6 kinases (S6K), eukaryotic translation initiation factor 4E (elF4E)-binding protein 1 (4E-BP1) and AKT, to control cell growth, proliferation, migration and survival in response to nutrients and growth factors. Glioblastoma (GB) is a devastating form of brain cancer, where the mTOR pathway is deregulated due to frequent upregulation of the Receptor Tyrosine Kinase/PI3K pathways and loss of the tumor suppressor phosphatase and tensin homologue (PTEN). Rapamycin and its analogs were less successful in clinical trials for patients with GB due to their incomplete inhibition of mTORC1 and the activation of mitogenic pathways via negative feedback loops. Here, the effects of selective ATP-competitive dual inhibitors of mTORC1 and mTORC2, Torin1, Torin2 and XL388, are reported. Torin2 exhibited concentration-dependent pharmacodynamic effects on inhibition of phosphorylation of the mTORC1 substrates S6KSer235/236 and 4E-BP1Thr37/46 as well as the mTORC2 substrate AKTSer473 resulting in suppression of tumor cell migration, proliferation and S-phase entry. Torin1 demonstrated similar effects, but only at higher doses. XL388 suppressed cell proliferation at a higher dose, but failed to inhibit cell migration. Treatment with Torin1 suppressed phosphorylation of proline rich AKT substrate of 40 kDa (PRAS40) at Threonine 246 (PRAS40Thr246) whereas Torin2 completely abolished it. XL388 treatment suppressed the phosphorylation of PRAS40Thr246 only at higher doses. Drug resistance analysis revealed that treatment of GB cells with XL388 rendered partial drug resistance, which was also seen to a lesser extent with rapamycin and Torin1 treatments. However, treatment with Torin2 completely eradicated the tumor cell population. These results strongly suggest that Torin2, compared to Torin1 or XL388, is more effective in suppressing mTORC1 and mTORC2, and therefore in the inhibition of the GB cell proliferation, dissemination and in overcoming resistance to therapy. These findings underscore the significance of Torin2 in the treatment of GB.
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Affiliation(s)
- Anubhav G Amin
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
| | - Seung Won Jeong
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
| | - John L Gillick
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
| | - Tolga Sursal
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
| | - Raj Murali
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
| | - Meena Jhanwar-Uniyal
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY 10595, USA
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10
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Song Y, Alyafei MS, Masmoudi K, Jaleel A, Ren M. Contributions of TOR Signaling on Photosynthesis. Int J Mol Sci 2021; 22:ijms22168959. [PMID: 34445664 PMCID: PMC8396432 DOI: 10.3390/ijms22168959] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 12/15/2022] Open
Abstract
The target of rapamycin (TOR) protein kinase is an atypical Ser/Thr protein kinase and evolutionally conserved among yeasts, plants, and mammals. TOR has been established as a central hub for integrating nutrient, energy, hormone, and environmental signals in all the eukaryotes. Despite the conserved functions across eukaryotes, recent research has shed light on the multifaceted roles of TOR signaling in plant-specific functional and mechanistic features. One of the most specific features is the involvement of TOR in plant photosynthesis. The recent development of tools for the functional analysis of plant TOR has helped to uncover the involvement of TOR signaling in several steps preceding photoautotrophy and maintenance of photosynthesis. Here, we present recent novel findings relating to TOR signaling and its roles in regulating plant photosynthesis, including carbon nutrient sense, light absorptions, and leaf and chloroplast development. We also provide some gaps in our understanding of TOR function in photosynthesis that need to be addressed in the future.
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Affiliation(s)
- Yun Song
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China;
| | - Mohammed Salem Alyafei
- Department of Integrative Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain 15551, United Arab Emirates; (M.S.A.); (K.M.); (A.J.)
| | - Khaled Masmoudi
- Department of Integrative Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain 15551, United Arab Emirates; (M.S.A.); (K.M.); (A.J.)
| | - Abdul Jaleel
- Department of Integrative Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain 15551, United Arab Emirates; (M.S.A.); (K.M.); (A.J.)
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China
- Correspondence: ; Tel.: +86-13527313471
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11
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Deng Z, Chen M, Liu Y, Xu S, Ouyang Y, Shi W, Jian D, Wang B, Liu F, Li J, Shi Q, Peng Q, Sha K, Xiao W, Liu T, Zhang Y, Zhang H, Wang Q, Sun L, Xie H, Li J. A positive feedback loop between mTORC1 and cathelicidin promotes skin inflammation in rosacea. EMBO Mol Med 2021; 13:e13560. [PMID: 33734592 PMCID: PMC8103105 DOI: 10.15252/emmm.202013560] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 12/13/2022] Open
Abstract
Rosacea is a chronic inflammatory skin disorder whose pathogenesis is unclear. Here, several lines of evidence were provided to demonstrate that mTORC1 signaling is hyperactivated in the skin, especially in the epidermis, of both rosacea patients and a mouse model of rosacea-like skin inflammation. Both mTORC1 deletion in epithelium and inhibition by its specific inhibitors can block the development of rosacea-like skin inflammation in LL37-induced rosacea-like mouse model. Conversely, hyperactivation of mTORC1 signaling aggravated rosacea-like features. Mechanistically, mTORC1 regulates cathelicidin through a positive feedback loop, in which cathelicidin LL37 activates mTORC1 signaling by binding to Toll-like receptor 2 (TLR2) and thus in turn increases the expression of cathelicidin itself in keratinocytes. Moreover, excess cathelicidin LL37 induces both NF-κB activation and disease-characteristic cytokine and chemokine production possibly via mTORC1 signaling. Topical application of rapamycin improved clinical symptoms in rosacea patients, suggesting mTORC1 inhibition can serve as a novel therapeutic avenue for rosacea.
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12
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Li T, Zhao X, Duan J, Cui S, Zhu K, Wan Y, Liu S, Peng Z, Wang L. Targeted inhibition of STAT3 in neural stem cells promotes neuronal differentiation and functional recovery in rats with spinal cord injury. Exp Ther Med 2021; 22:711. [PMID: 34007320 PMCID: PMC8120646 DOI: 10.3892/etm.2021.10143] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 02/02/2021] [Indexed: 12/12/2022] Open
Abstract
STAT3 is expressed in neural stem cells (NSCs), where a number of studies have previously shown that STAT3 is involved in regulating NSC differentiation. However, the possible molecular mechanism and role of STAT3 in spinal cord injury (SCI) remain unclear. In the present study, the potential effect of STAT3 in NSCs was first investigated by using short hairpin RNA (shRNA)-mediated STAT3 knockdown in rat NSCs in vitro. Immunofluorescence of β3-tubulin and glial fibrillary acidic protein staining and western blotting showed that knocking down STAT3 expression promoted NSC neuronal differentiation, where the activity of mTOR was upregulated. Subsequently, rats underwent laminectomy and complete spinal cord transection followed by transplantation of NSCs transfected with control-shRNA or STAT3-shRNA at the injured site in vivo. Spinal cord-evoked potentials and the Basso-Beattie-Bresnahan scores were used to examine functional recovery. In addition, axonal regeneration and tissue repair were assessed using retrograde tracing with FluoroGold, hematoxylin and eosin, Nissl and immunofluorescence staining of β3-tubulin, glial fibrillary acidic protein and microtubule-associated protein 2 following SCI. The results showed that transplantation with NSCs transfected with STAT3-RNA enhanced functional recovery following SCI and promoted tissue repair in rats, in addition to improving neuronal differentiation of the transplanted NSCs in the injury site. Taken together, in vitro and in vivo evidence that inhibiting STAT3 could promote NSC neuronal differentiation was demonstrated in the present study. Therefore, transplantation with NSCs with STAT3 expression knocked down appears to hold promising potential for enhancing the benefit of NSC-mediated regenerative cell therapy for SCI.
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Affiliation(s)
- Tingting Li
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510700, P.R. China
| | - Xiaoyang Zhao
- Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Jing Duan
- Department of Pathology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Shangbin Cui
- Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Kai Zhu
- Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yong Wan
- Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Shaoyu Liu
- Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Zhiming Peng
- Department of Orthopaedics, Air Force General Hospital, Beijing 100142, P.R. China
| | - Le Wang
- Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
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13
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Dapergola E, Menegazzi P, Raabe T, Hovhanyan A. Light Stimuli and Circadian Clock Affect Neural Development in Drosophila melanogaster. Front Cell Dev Biol 2021; 9:595754. [PMID: 33763414 PMCID: PMC7982892 DOI: 10.3389/fcell.2021.595754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Endogenous clocks enable organisms to adapt cellular processes, physiology, and behavior to daily variation in environmental conditions. Metabolic processes in cyanobacteria to humans are under the influence of the circadian clock, and dysregulation of the circadian clock causes metabolic disorders. In mouse and Drosophila, the circadian clock influences translation of factors involved in ribosome biogenesis and synchronizes protein synthesis. Notably, nutrition signals are mediated by the insulin receptor/target of rapamycin (InR/TOR) pathways to regulate cellular metabolism and growth. However, the role of the circadian clock in Drosophila brain development and the potential impact of clock impairment on neural circuit formation and function is less understood. Here we demonstrate that changes in light stimuli or disruption of the molecular circadian clock cause a defect in neural stem cell growth and proliferation. Moreover, we show that disturbed cell growth and proliferation are accompanied by reduced nucleolar size indicative of impaired ribosomal biogenesis. Further, we define that light and clock independently affect the InR/TOR growth regulatory pathway due to the effect on regulators of protein biosynthesis. Altogether, these data suggest that alterations in InR/TOR signaling induced by changes in light conditions or disruption of the molecular clock have an impact on growth and proliferation properties of neural stem cells in the developing Drosophila brain.
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Affiliation(s)
- Eleni Dapergola
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Pamela Menegazzi
- Neurobiology and Genetics, Theodor-Boveri Institute, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Thomas Raabe
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Anna Hovhanyan
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
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14
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A Tour of TOR Complex Signaling in Plants. Trends Biochem Sci 2020; 46:417-428. [PMID: 33309324 DOI: 10.1016/j.tibs.2020.11.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/26/2020] [Accepted: 11/09/2020] [Indexed: 01/07/2023]
Abstract
To identify the appropriate times for growth and development, organisms must sense and process information about the availability of nutrients, energy status, and environmental cues. For sessile eukaryotes such as plants, integrating such information can be critical in life or death decisions. For nearly 30 years, the conserved phosphatidylinositol 3-kinase-related protein kinases (PIKKs) target of rapamycin (TOR) has been established as a central hub for integrating external and internal metabolic cues. Despite the functional conservation across eukaryotes, the TOR complex has evolved specific functional and mechanistic features in plants. Here, we present recent findings on the plant TOR complex that highlight the conserved and unique nature of this critical growth regulator and its role in multiple aspects of plant life.
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15
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Lee HY, Hong IS. Metabolic Regulation and Related Molecular Mechanisms in Various Stem Cell Functions. Curr Stem Cell Res Ther 2020; 15:531-546. [PMID: 32394844 DOI: 10.2174/1574888x15666200512105347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/11/2020] [Accepted: 03/02/2020] [Indexed: 02/07/2023]
Abstract
Recent studies on the mechanisms that link metabolic changes with stem cell fate have deepened our understanding of how specific metabolic pathways can regulate various stem cell functions during the development of an organism. Although it was originally thought to be merely a consequence of the specific cell state, metabolism is currently known to play a critical role in regulating the self-renewal capacity, differentiation potential, and quiescence of stem cells. Many studies in recent years have revealed that metabolic pathways regulate various stem cell behaviors (e.g., selfrenewal, migration, and differentiation) by modulating energy production through glycolysis or oxidative phosphorylation and by regulating the generation of metabolites, which can modulate multiple signaling pathways. Therefore, a more comprehensive understanding of stem cell metabolism could allow us to establish optimal culture conditions and differentiation methods that would increase stem cell expansion and function for cell-based therapies. However, little is known about how metabolic pathways regulate various stem cell functions. In this context, we review the current advances in metabolic research that have revealed functional roles for mitochondrial oxidative phosphorylation, anaerobic glycolysis, and oxidative stress during the self-renewal, differentiation and aging of various adult stem cell types. These approaches could provide novel strategies for the development of metabolic or pharmacological therapies to promote the regenerative potential of stem cells and subsequently promote their therapeutic utility.
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Affiliation(s)
- Hwa-Yong Lee
- Department of Biomedical Science, Jungwon University, 85 Goesan-eup, Munmu-ro, Goesan-gun, Chungcheongbuk-do 367-700, Korea
| | - In-Sun Hong
- Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea
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16
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Rapamycin induces morphological and physiological changes without increase in lipid content in Ustilago maydis. Arch Microbiol 2020; 202:1211-1221. [PMID: 32088730 DOI: 10.1007/s00203-020-01833-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/04/2020] [Accepted: 02/07/2020] [Indexed: 12/19/2022]
Abstract
The evolutionarily conserved serine/threonine kinase TOR recruits different subunits to assemble the Target of Rapamycin Complex 1 (TORC1), which is inhibited by rapamycin and regulates ribosome biogenesis, autophagy, and lipid metabolism by regulating the expression of lipogenic genes. In addition, TORC1 participates in the cell cycle, increasing the length of the G2 phase. In the present work, we investigated the effect of rapamycin on cell growth, cell morphology and neutral lipid metabolism in the phytopathogenic fungus Ustilago maydis. Inhibition of TORC1 by rapamycin induced the formation of septa that separate the nuclei that were formed after mitosis. Regarding neutral lipid metabolism, a higher accumulation of triacylglycerols was not detected, but the cells did contain large lipid bodies, which suggests that small lipid bodies became fused into big lipid droplets. Vacuoles showed a similar behavior as the lipid bodies, and double labeling with Blue-CMAC and BODIPY indicates that vacuoles and lipid bodies were independent organelles. The results suggest that TORC1 has a role in cell morphology, lipid metabolism, and vacuolar physiology in U. maydis.
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17
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Khorraminejad-Shirazi M, Sani M, Talaei-Khozani T, Dorvash M, Mirzaei M, Faghihi MA, Monabati A, Attar A. AICAR and nicotinamide treatment synergistically augment the proliferation and attenuate senescence-associated changes in mesenchymal stromal cells. Stem Cell Res Ther 2020; 11:45. [PMID: 32014016 PMCID: PMC6998366 DOI: 10.1186/s13287-020-1565-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 01/05/2020] [Accepted: 01/19/2020] [Indexed: 12/11/2022] Open
Abstract
Background Mesenchymal stromal cell (MSC) stemness capacity diminishes over prolonged in vitro culture, which negatively affects their application in regenerative medicine. To slow down the senescence of MSCs, here, we have evaluated the in vitro effects of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator, and nicotinamide (NAM), an activator of sirtuin1 (SIRT1). Methods Human adipose-derived MSCs were cultured to passage (P) 5. Subsequently, the cells were grown in either normal medium alone (control group), the medium supplemented with AICAR (1 mM) and NAM (5 mM), or in the presence of both for 5 weeks to P10. Cell proliferation, differentiation capacity, level of apoptosis and autophagy, morphological changes, total cellular reactive oxygen species (ROS), and activity of mTORC1 and AMPK were compared among different treatment groups. Results MSCs treated with AICAR, NAM, or both displayed an increase in proliferation and osteogenic differentiation, which was augmented in the group receiving both. Treatment with AICAR or NAM led to decreased expression of β-galactosidase, reduced accumulation of dysfunctional lysosomes, and characteristic morphologic features of young MSCs. Furthermore, while NAM administration could significantly reduce the total cellular ROS in aged MSCs, AICAR treatment did not. Moreover, AICAR-treated cells possess a high proliferation capacity; however, they also show the highest level of cellular apoptosis. The observed effects of AICAR and NAM were in light of the attenuated mTORC1 activity and increased AMPK activity and autophagy. Conclusions Selective inhibition of mTORC1 by AICAR and NAM boosts autophagy, retains MSCs’ self-renewal and multi-lineage differentiation capacity, and postpones senescence-associated changes after prolonged in vitro culture. Additionally, co-administration of AICAR and NAM shows an additive or probably a synergistic effect on cellular senescence.
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Affiliation(s)
- Mohammadhossein Khorraminejad-Shirazi
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.,Cell and Molecular Medicine Student Research Group, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahsa Sani
- Tissue Engineering Department, School of Advanced Medical Science and Technology, Shiraz University of Medical Science, Shiraz, Iran.,Tissue Engineering Lab, Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Tahereh Talaei-Khozani
- Tissue Engineering Lab, Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammadreza Dorvash
- Cell and Molecular Medicine Student Research Group, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.,Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Malihe Mirzaei
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Ali Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ahmad Monabati
- Department of Pathology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.,Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Armin Attar
- Department of Cardiovascular Medicine, Shiraz University of Medical Sciences, PO Box 71344-1864, Shiraz, Iran.
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18
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Vassilieva I, Kosheverova V, Vitte M, Kamentseva R, Shatrova A, Tsupkina N, Skvortsova E, Borodkina A, Tolkunova E, Nikolsky N, Burova E. Paracrine senescence of human endometrial mesenchymal stem cells: a role for the insulin-like growth factor binding protein 3. Aging (Albany NY) 2020; 12:1987-2004. [PMID: 31951594 PMCID: PMC7053595 DOI: 10.18632/aging.102737] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/02/2020] [Indexed: 12/11/2022]
Abstract
Stress-induced premature cell senescence is well recognized to be accompanied by emerging the senescence-associated secretory phenotype (SASP). Secreted SASP factors can promote the senescence of normal neighboring cells through autocrine/paracrine pathways and regulate the senescence response, as well. Regarding human endometrium-derived mesenchymal stem cells (MESCs), the SASP regulation mechanisms as well as paracrine activity of senescent cells have not been studied yet. Here, we examined the role of insulin-like growth factor binding protein 3 (IGFBP3) in the paracrine senescence induction in young MESCs. The H2O2-induced premature senescence of MESCs led to increased IGFBP3 in conditioned media (CM). The inhibitory analysis of both MAPK and PI3K signaling pathways showed that IGFBP3 releasing from senescent cells is mainly regulated by PI3K/Akt pathway activity. IGFBP3 appears to be an important senescence-mediating factor as its immunodepletion from the senescent CM weakened the pro-senescent effect of CM on young MESCs and promoted their growth. In contrast, young MESCs acquired the senescence phenotype in response to simultaneous addition of recombinant IGFBP3 (rIGFBP3). The mechanism of extracellular IGFBP3 internalization was also revealed. The present study is the first to demonstrate a significant role of extracellular IGFBP3 in paracrine senescence induction of young MESCs.
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Affiliation(s)
- Irina Vassilieva
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Vera Kosheverova
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Mikhail Vitte
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Rimma Kamentseva
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Alla Shatrova
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Natalia Tsupkina
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Elena Skvortsova
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Aleksandra Borodkina
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Elena Tolkunova
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Nikolay Nikolsky
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Elena Burova
- Department of Intracellular Signaling and Transport, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
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19
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Selective Upregulation by Theanine of Slc38a1 Expression in Neural Stem Cell for Brain Wellness. Molecules 2020; 25:molecules25020347. [PMID: 31952134 PMCID: PMC7024158 DOI: 10.3390/molecules25020347] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/15/2020] [Indexed: 12/22/2022] Open
Abstract
Theanine is an amino acid abundant in green tea with an amide moiety analogous to glutamine (GLN) rather than glutamic acid (Glu) and GABA, which are both well-known as amino acid neurotransmitters in the brain. Theanine has no polyphenol and flavonoid structures required for an anti-oxidative property as seen with catechins and tannins, which are more enriched in green tea. We have shown marked inhibition by this exogenous amino acid theanine of the uptake of [3H]GLN, but not of [3H]Glu, in rat brain synaptosomes. Beside a ubiquitous role as an endogenous amino acid, GLN has been believed to be a main precursor for the neurotransmitter Glu sequestered in a neurotransmitter pool at glutamatergic neurons in the brain. The GLN transporter solute carrier 38a1 (Slc38a1) plays a crucial role in the incorporation of extracellular GLN for the intracellular conversion to Glu by glutaminase and subsequent sequestration at synaptic vesicles in neurons. However, Slc38a1 is also expressed by undifferentiated neural progenitor cells (NPCs) not featuring a neuronal phenotype. NPCs are derived from a primitive stem cell endowed to proliferate for self-renewal and to commit differentiation to several daughter cell lineages such as neurons, astrocytes, and oligodendrocytes. In vitro culture with theanine leads to the marked promotion of the generation of new neurons together with selective upregulation of Slc38a1 transcript expression in NPCs. In this review, we will refer to a possible novel neurogenic role of theanine for brain wellness through a molecular mechanism relevant to facilitated neurogenesis with a focus on Slc38a1 expressed by undifferentiated NPCs on the basis of our accumulating findings to date.
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20
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Jin X, Kang X, Zhao L, Xu M, Xie T, Li H, Li F, Qian Z, Ma Z, Zhang Y, Yang W, Zhang Z, Gao X, Chen Q, Sun H, Wu S. Cartilage Ablation of Sirt1 Causes Inhibition of Growth Plate Chondrogenesis by Hyperactivation of mTORC1 Signaling. Endocrinology 2019; 160:3001-3017. [PMID: 31599935 DOI: 10.1210/en.2019-00427] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 10/04/2019] [Indexed: 01/04/2023]
Abstract
A growing body of evidence implies a pivotal role of sirtuin-1 (Sirt1) in chondrocyte function and homeostasis; however, its underlying mechanisms mediating chondrogenesis, which is an essential process for physiological skeletal growth, are still poorly understood. In the current study, we generated TamCartSirt1-/- [Sirt1 conditional knockout (cKO)] mice to explore the role of Sirt1 during postnatal endochondral ossification. Compared with control mice, cKO mice exhibited growth retardation associated with inhibited chondrocyte proliferation and hypertrophy, as well as activated apoptosis. These effects were regulated by hyperactivation of mammalian target of rapamycin complex 1 (mTORC1) signaling, and thereby inhibition of autophagy and induction of endoplasmic reticulum stress in growth plate chondrocytes. IP injection of the mTORC1 inhibitor rapamycin to mice with Sirt1 deletion partially neutralized such inhibitory effects of Sirt1 ablation on longitudinal bone growth, indicating the causative link between SIRT1 and mTORC1 signaling in the growth plate. Mechanistically, SIRT1 interacted with tuberous sclerosis complex 2 (TSC2), a key upstream negative regulator of mTORC1 signaling, and loss of Sirt1 inhibited TSC2 expression, resulting in hyperactivated mTORC1 signaling in chondrocytes. In conclusion, our findings suggest that loss of Sirt1 may trigger mTORC1 signaling in growth plate chondrocytes and contributes to growth retardation, thus indicating that SIRT1 is an important regulator during chondrogenesis and providing new insights into the clinical potential of SIRT1 in bone development.
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Affiliation(s)
- Xinxin Jin
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Xiaomin Kang
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Liting Zhao
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Mao Xu
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Tianping Xie
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Huixia Li
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Fang Li
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Zhuang Qian
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Zhengmin Ma
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Ying Zhang
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Wei Yang
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Zhuanmin Zhang
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Xin Gao
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Qian Chen
- Department of Orthopaedics, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island
- Bone and Joint Research Center, The First Affiliated Hospital of Medical School, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Hongzhi Sun
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Shufang Wu
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
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21
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Yang Q, Yin W, Chen Y, Zhu D, Yin J, Zhang C, Gao Y. Betaine alleviates alcohol-induced osteonecrosis of the femoral head via mTOR signaling pathway regulation. Biomed Pharmacother 2019; 120:109486. [PMID: 31586901 DOI: 10.1016/j.biopha.2019.109486] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/14/2019] [Accepted: 09/22/2019] [Indexed: 02/07/2023] Open
Abstract
Osteonecrosis of the femoral head (ONFH) is usually caused by chronic and excessive alcohol dependency, and this condition largely suppresses the osteogenic differentiation of bone mesenchymal stem cells (BMSCs). As a trimethyl derivative of glycine, betaine is an important human nutrient that regulates a series of vital biological processes, including oxidative stress, inflammatory responses, osteoblast differentiation and cellular apoptosis. However, no study has investigated the role of betaine in alcohol-induced ONFH. In this study, we hypothesized that betaine might have protective effects on ethanol-treated BMSCs and decrease the morbidity of alcohol-induced ONFH in a rat model. In vitro, we found that ethanol significantly downregulated the expression of osteocalcin (OCN), collagen 1 (COL1) and RUNX2 via activating the mammalian target of rapamycin (mTOR) signaling cascade. However, the inhibitory effects were rescued by betaine co-treatment at concentrations of 1 mM and 10 mM. In vivo, the typical ONFH pathological changes in a rat model of alcohol-induced ONFH were investigated by using multiple methods, including hematoxylin-eosin staining, micro-CT scans, TdT-mediated dUTP nick end labeling (TUNEL) assays and immunohistochemical staining for OCN and COL1. Osteonecrotic lesions of the femoral head could be alleviated by betaine as evidenced by significant histological and radiological improvements. Collectively, betaine plays a protective role against ethanol-induced suppression of osteogenesis and mineralization of hBMSCs and is thus a potential pharmacotherapy for alcohol-induced ONFH in vivo.
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Affiliation(s)
- Qianhao Yang
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Wenjing Yin
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Yixuan Chen
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Daoyu Zhu
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Junhui Yin
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China; Institute of Microsurgery on Extremities, Shanghai, 200233, China
| | - Changqing Zhang
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China; Institute of Microsurgery on Extremities, Shanghai, 200233, China.
| | - Youshui Gao
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China.
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22
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Fabris G, Dumortier O, Pisani DF, Gautier N, Van Obberghen E. Amino acid-induced regulation of hepatocyte growth: possible role of Drosha. Cell Death Dis 2019; 10:566. [PMID: 31332188 PMCID: PMC6646398 DOI: 10.1038/s41419-019-1779-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/23/2019] [Accepted: 06/21/2019] [Indexed: 12/14/2022]
Abstract
In an adult healthy liver, hepatocytes are in a quiescent stage unless a physical injury, such as ablation, or a toxic attack occur. Indeed, to maintain their crucial organismal homeostatic role, the damaged or remaining hepatocytes will start proliferating to restore their functional mass. One of the limiting conditions for cell proliferation is amino-acid availability, necessary both for the synthesis of proteins important for cell growth and division, and for the activation of the mTOR pathway, known for its considerable role in the regulation of cell proliferation. The overarching aim of our present work was to investigate the role of amino acids in the regulation of the switch between quiescence and growth of adult hepatocytes. To do so we used non-confluent primary adult rat hepatocytes as a model of partially ablated liver. We discovered that the absence of amino acids induces in primary rat hepatocytes the entrance in a quiescence state together with an increase in Drosha protein, which does not involve the mTOR pathway. Conversely, Drosha knockdown allows the hepatocytes, quiescent after amino-acid deprivation, to proliferate again. Further, hepatocyte proliferation appears to be independent of miRNAs, the canonical downstream partners of Drosha. Taken together, our observations reveal an intriguing non-canonical action of Drosha in the control of growth regulation of adult hepatocytes responding to a nutritional strain, and they may help to design novel preventive and/or therapeutic approaches for hepatic failure.
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Affiliation(s)
- Gaia Fabris
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France.,Université Côte d'Azur, CNRS, LP2M, Nice, France
| | | | | | - Nadine Gautier
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France.,Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France
| | - Emmanuel Van Obberghen
- Université Côte d'Azur, CHU, Inserm, CNRS, IRCAN, Nice, France. .,Université Côte d'Azur, CHU, CNRS, LP2M, Nice, France.
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23
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mTOR Signaling Pathway in Cancer Targets Photodynamic Therapy In Vitro. Cells 2019; 8:cells8050431. [PMID: 31075885 PMCID: PMC6563036 DOI: 10.3390/cells8050431] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/22/2019] [Accepted: 04/30/2019] [Indexed: 01/03/2023] Open
Abstract
The Mechanistic or Mammalian Target of Rapamycin (mTOR) is a major signaling pathway in eukaryotic cells belonging to the P13K-related kinase family of the serine/threonine protein kinase. It has been established that mTOR plays a central role in cellular processes and implicated in various cancers, diabetes, and in the aging process with very poor prognosis. Inhibition of the mTOR pathway in the cells may improve the therapeutic index in cancer treatment. Photodynamic therapy (PDT) has been established to selectively eradicate neoplasia at clearly delineated malignant lesions. This review highlights recent advances in understanding the role or regulation of mTOR in cancer therapy. It also discusses how mTOR currently contributes to cancer as well as future perspectives on targeting mTOR therapeutically in cancer in vitro.
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24
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A novel de novo MTOR gain-of-function variant in a patient with Smith-Kingsmore syndrome and Antiphospholipid syndrome. Eur J Hum Genet 2019; 27:1369-1378. [PMID: 31053780 DOI: 10.1038/s41431-019-0418-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 03/21/2019] [Accepted: 04/16/2019] [Indexed: 01/22/2023] Open
Abstract
We report the clinical, biochemical and genetic findings from a Spanish girl of Caucasian origin who presented with macrocephaly, dysmorphic facial features, developmental delay, hypotonia, combined oxidative phosphorylation (OxPhos) deficiency, epilepsy and anti-phospholipid antibodies (aPL). Whole-exome sequencing (WES) uncovered a heterozygous variant in the MTOR gene (NM_004958.3: c.7235A>T: p.(Asp2412Val)) that encodes for the Serine/threonine-protein kinase mTOR. The substrates phosphorylation experiments demonstrated that this variant exerts its effect by gain-of-function (GOF) and autosomal dominant mechanism. GOF variants in this protein have been associated with Smith-Kingsmore syndrome (SKS), a rare autosomal dominant disorder characterized by intellectual disability, macrocephaly, seizure, developmental delay and dysmorphic facial features. Furthermore, the mTOR pathway has been demonstrated previously to be involved in many types of endothelium injuries including the antiphospholipid syndrome (APS), a systemic autoimmune disease characterized by the production of aPL with recurrent vascular thrombosis. Therefore, our patient is the first one with an mTOR variant and diagnosed with SKS and APS. In conclusion, our data expand both the genetic and phenotypic spectrum associated with MTOR gene variants.
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A C-Met chemical inhibitor promotes fracture healing through interacting with osteogenic differentiation via the mTORC1 pathway. Exp Cell Res 2019; 381:50-56. [PMID: 31034806 DOI: 10.1016/j.yexcr.2019.03.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 01/16/2023]
Abstract
Currently, HGF/C-Met signaling inhibitors are being investigated to determine if they are useful for enhancing progenitor cell differentiation into osteoblasts, and one of them, BMS-777607, has been utilized to treat osteoporosis and bone loss in several types of diseases. However, whether BMS-777607 could be a potential treatment during fracture healing remains elusive. Here, we examined the therapeutic effects of BMS-777607 on bone fracture healing in a mouse model. In vivo radiological analysis showed that fractures treated with BMS-777607 exhibited accelerated osteotylus formation during the early stage of bone healing. Thereafter, the Safranin O staining evaluation indicated that the structure of the external callus in the Treatment group was larger than that in the Vehicle group at week 2. Furthermore, cellular proliferation of MC3T3-E1 was not significantly affected by low concentrations of BMS-777607. In addition, stimulation of osteoblast differentiation and mineralization was a result of BMS-777607 inducing the expression of Runx2 and Col1, and this osteogenic ability, at least in part, was mediated through the mammalian target of rapamycin complex 1 (mTORC1) signaling in vitro. Conclusively, BMS-777607 has been identified as a therapeutic agent to improve bone formation during fracture healing, and its osteogenic effects on osteoblast differentiation were mediated via the mTORC1 signaling pathway.
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26
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Sekii K, Yorimoto S, Okamoto H, Nagao N, Maezawa T, Matsui Y, Yamaguchi K, Furukawa R, Shigenobu S, Kobayashi K. Transcriptomic analysis reveals differences in the regulation of amino acid metabolism in asexual and sexual planarians. Sci Rep 2019; 9:6132. [PMID: 30992461 PMCID: PMC6467871 DOI: 10.1038/s41598-019-42025-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 03/22/2019] [Indexed: 12/25/2022] Open
Abstract
Many flatworms can alternate between asexual and sexual reproduction. This is a powerful reproductive strategy enabling them to benefit from the features of the two reproductive modes, namely, rapid multiplication and genetic shuffling. The two reproductive modes are enabled by the presence of pluripotent adult stem cells (neoblasts), by generating any type of tissue in the asexual mode, and producing and maintaining germ cells in the sexual mode. In the current study, RNA sequencing (RNA-seq) was used to compare the transcriptomes of two phenotypes of the planarian Dugesia ryukyuensis: an asexual OH strain and an experimentally sexualized OH strain. Pathway enrichment analysis revealed striking differences in amino acid metabolism in the two worm types. Further, the analysis identified serotonin as a new bioactive substance that induced the planarian ovary de novo in a postembryonic manner. These findings suggest that different metabolic states and physiological conditions evoked by sex-inducing substances likely modulate stem cell behavior, depending on their different function in the asexual and sexual reproductive modes. The combination of RNA-seq and a feeding assay in D. ryukyuensis is a powerful tool for studying the alternation of reproductive modes, disentangling the relationship between gene expression and chemical signaling molecules.
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Affiliation(s)
- Kiyono Sekii
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Shunta Yorimoto
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Hikaru Okamoto
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Nanna Nagao
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Takanobu Maezawa
- Department of Integrated Science and Technology, National Institute of Technology, Tsuyama College, 624-1 Numa, Tsuyama, Okayama, 708-8509, Japan
| | - Yasuhisa Matsui
- Cell Resource Center for Biomedical Research, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Sendai, 980-8575, Japan
| | - Katsushi Yamaguchi
- NIBB Core Research Facilities, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, 444-8585, Japan
| | - Ryohei Furukawa
- Division of Biomedical Information Analysis, Iwate Tohoku Medical Megabank Organization, Iwate Medical University, 2-1-1 Nishitokuda, Yanaba-cho, Shiwa-gun, Iwate, 028-3694, Japan. .,Department of Biology, Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8521, Japan.
| | - Shuji Shigenobu
- NIBB Core Research Facilities, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, 444-8585, Japan. .,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 38 Nishigonaka Myodaiji, Okazaki, 444-8585, Japan.
| | - Kazuya Kobayashi
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan.
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Jhanwar-Uniyal M, Wainwright JV, Mohan AL, Tobias ME, Murali R, Gandhi CD, Schmidt MH. Diverse signaling mechanisms of mTOR complexes: mTORC1 and mTORC2 in forming a formidable relationship. Adv Biol Regul 2019; 72:51-62. [PMID: 31010692 DOI: 10.1016/j.jbior.2019.03.003] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/25/2019] [Accepted: 03/25/2019] [Indexed: 02/07/2023]
Abstract
Activation of Mechanistic target of rapamycin (mTOR) signaling plays a crucial role in tumorigenesis of numerous malignancies including glioblastoma (GB). The Canonical PI3K/Akt/mTOR signaling cascade is commonly upregulated due to loss of the tumor suppressorm PTEN, a phosphatase that acts antagonistically to the kinase (PI3K) in conversion of PIP2 to PIP3. mTOR forms two multiprotein complexes, mTORC1 and mTORC2 which are composed of discrete protein binding partners to regulate cell growth, motility, and metabolism. These complexes are sensitive to distinct stimuli, as mTORC1 is sensitive to nutrients while mTORC2 is regulated via PI3K and growth factor signaling. The main function of mTORC1 is to regulate protein synthesis and cell growth through downstream molecules: 4E-BP1 (also called EIF4E-BP1) and S6K. On the other hand, mTORC2 is responsive to growth factor signaling by phosphorylating the C-terminal hydrophobic motif of some AGC kinases like Akt and SGK and it also plays a crucial role in maintenance of normal and cancer cells through its association with ribosomes, and is involved in cellular metabolic regulation. mTORC1 and mTORC2 regulate each other, as shown by the fact that Akt regulates PRAS40 phosphorylation, which disinhibits mTORC1 activity, while S6K regulates Sin1 to modulate mTORC2 activity. Allosteric inhibitors of mTOR, rapamycin and rapalogs, remained ineffective in clinical trials of Glioblastoma (GB) patients, in part due to their incomplete inhibition of mTORC1 as well as unexpected activation of mTOR via the loss of negative feedback loops. In recent years, novel ATP binding inhibitors of mTORC1 and mTORC2 suppress mTORC1 activity completely by total dephosphorylation of its downstream substrate pS6KSer235/236, while effectively suppressing mTORC2 activity, as demonstrated by complete dephosphorylation of pAKTSer473. Furthermore by these novel combined mTORC1/mTORC2 inhibitors reduced the proliferation and self-renewal of GB cancer stem cells. However, a search of more effective way to target mTOR has generated a third generation inhibitor of mTOR, "Rapalink", that bivalently combines rapamycin with an ATP-binding inhibitor, which effectively abolishes the mTORC1 activity. All in all, the effectiveness of inhibitors of mTOR complexes can be judged by their ability to suppress both mTORC1/mTORC2 and their ability to impede both cell proliferation and migration along with aberrant metabolic pathways.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA.
| | - John V Wainwright
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA
| | - Avinash L Mohan
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA
| | - Michael E Tobias
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA
| | - Raj Murali
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA
| | - Meic H Schmidt
- Department of Neurosurgery, Westchester Medical Center / New York Medical College, Valhalla, NY, 10595, USA
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28
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Grafanaki K, Anastasakis D, Kyriakopoulos G, Skeparnias I, Georgiou S, Stathopoulos C. Translation regulation in skin cancer from a tRNA point of view. Epigenomics 2018; 11:215-245. [PMID: 30565492 DOI: 10.2217/epi-2018-0176] [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: 12/15/2022] Open
Abstract
Protein synthesis is a central and dynamic process, frequently deregulated in cancer through aberrant activation or expression of translation initiation factors and tRNAs. The discovery of tRNA-derived fragments, a new class of abundant and, in some cases stress-induced, small Noncoding RNAs has perplexed the epigenomics landscape and highlights the emerging regulatory role of tRNAs in translation and beyond. Skin is the biggest organ in human body, which maintains homeostasis of its multilayers through regulatory networks that induce translational reprogramming, and modulate tRNA transcription, modification and fragmentation, in response to various stress signals, like UV irradiation. In this review, we summarize recent knowledge on the role of translation regulation and tRNA biology in the alarming prevalence of skin cancer.
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Affiliation(s)
- Katerina Grafanaki
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece.,Department of Dermatology, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Dimitrios Anastasakis
- National Institute of Musculoskeletal & Arthritis & Skin, NIH, 50 South Drive, Room 1152, Bethesda, MD 20892, USA
| | - George Kyriakopoulos
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Ilias Skeparnias
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Sophia Georgiou
- Department of Dermatology, School of Medicine, University of Patras, 26504 Patras, Greece
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29
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Kornakiewicz A, Czarnecka AM, Khan MI, Krasowski P, Kotrys AV, Szczylik C. Effect of Everolimus on Heterogenous Renal Cancer Cells Populations Including Renal Cancer Stem Cells. Stem Cell Rev Rep 2018; 14:385-397. [PMID: 29508215 DOI: 10.1007/s12015-018-9804-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aim of this study was to compare effect of everolimus on growth of different renal cell carcinoma (RCC) populations and develop experimental design to measure the early response of everolimus in clear cell RCC (ccRCC) cell lines including renal cancer stem cells. Effect of everolimus on RCC cell lines which include primary (786-0) and metastatic (ACHN) RCC cell lines as well as heterogenous populations of tumor cells of different histological RCC subtypes (clear cell RCC and papillary RCC) was measured when treated with everolimus in the range of 1-9 µM. Gene expression profiling using microarray was performed to determine the early response to everolimus in ccRCC cell lines after optimizing concentration of drug. Gene Set Enrichment Analysis (GSEA) was done which mainly focused on basic genes related to mTOR, hormonal and metabolic pathways. Everolimus acts on RCC cells in a dose-dependent manner. In all examined cell lines IC50 dose was possible to calculate after the third day of treatment. In ccRCC lines (parental and stem cell) everolimus changes expression of mTOR complexes elements and elements of related pathways when treated with optimized doses of drug. Characteristic expression profile for ccRCC cells at an early exposure time to everolimus is to elucidate. Wevarie include some basic observations derived from data analysis in the context of mechanism of action of drug with a view to better understand biology of renal cancer cells.
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Affiliation(s)
- Anna Kornakiewicz
- Molecular Oncology Laboratory, Department of Oncology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland. .,Postgraduate School of Molecular Medicine, Warsaw Medical University, Żwirki i Wigury 61, 02-091, Warsaw, Poland.
| | - Anna M Czarnecka
- Molecular Oncology Laboratory, Department of Oncology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland
| | - Mohammed I Khan
- Molecular Oncology Laboratory, Department of Oncology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland
| | - Paweł Krasowski
- Molecular Oncology Laboratory, Department of Oncology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland
| | - Anna V Kotrys
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Laboratory of RNA Biology and Functional Genomics, Pawińskiego 5A, 02-106, Warsaw, Poland
| | - Cezary Szczylik
- Molecular Oncology Laboratory, Department of Oncology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland.,Warsaw Medical University, Żwirki i Wigury 61, 02-091, Warsaw, Poland
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30
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Salvia R, Nardiello M, Scieuzo C, Scala A, Bufo SA, Rao A, Vogel H, Falabella P. Novel Factors of Viral Origin Inhibit TOR Pathway Gene Expression. Front Physiol 2018; 9:1678. [PMID: 30534083 PMCID: PMC6275226 DOI: 10.3389/fphys.2018.01678] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 11/08/2018] [Indexed: 01/06/2023] Open
Abstract
Polydnaviruses (PDVs) are obligate symbionts of endoparasitoid wasps, which exclusively attack the larval stages of their lepidopteran hosts. The Polydnavirus is injected by the parasitoid female during oviposition to selectively infect host tissues by the expression of viral genes without undergoing replication. Toxoneuron nigriceps bracovirus (TnBV) is associated with Toxoneuron nigriceps (Hymenoptera: Braconidae) wasp, an endoparasitoid of the tobacco budworm larval stages, Heliothis virescens (Lepidoptera: Noctuidae). Previous studies showed that TnBV is responsible for alterations in host physiology. The arrest of ecdysteroidogenesis is the main alteration which occurs in last (fifth) instar larvae and, as a consequence, prevents pupation. TnBV induces the functional inactivation of H. virescens prothoracic glands (PGs), resulting in decreased protein synthesis and phosphorylation. Previous work showed the involvement of the PI3K/Akt/TOR pathway in H. virescens PG ecdysteroidogenesis. Here, we demonstrate that this cellular signaling is one of the targets of TnBV infection. Western blot analysis and enzyme immunoassay (EIA) showed that parasitism inhibits ecdysteroidogenesis and the phosphorylation of the two targets of TOR (4E-BP and S6K), despite the stimulation of PTTH contained in the brain extract. Using a transcriptomic approach, we identified viral genes selectively expressed in last instar H. virescens PGs, 48 h after parasitization, and evaluated expression levels of PI3K/Akt/TOR pathway genes in these tissues. The relative expression of selected genes belonging to the TOR pathway (tor, 4e-bp, and s6k) in PGs of parasitized larvae was further confirmed by qRT-PCR. The down-regulation of these genes in PGs of parasitized larvae supports the hypothesis of TnBV involvement in blocking ecdysteroidogenesis, through alterations of the PI3K/Akt/TOR pathway at the transcriptional level.
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Affiliation(s)
- Rosanna Salvia
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Marisa Nardiello
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Carmen Scieuzo
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Andrea Scala
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Sabino A. Bufo
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Asha Rao
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Heiko Vogel
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Patrizia Falabella
- Department of Biology, Texas A&M University, College Station, TX, United States
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31
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Choi HK, Yuan H, Fang F, Wei X, Liu L, Li Q, Guan JL, Liu F. Tsc1 Regulates the Balance Between Osteoblast and Adipocyte Differentiation Through Autophagy/Notch1/β-Catenin Cascade. J Bone Miner Res 2018; 33:2021-2034. [PMID: 29924882 PMCID: PMC6248888 DOI: 10.1002/jbmr.3530] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 06/07/2018] [Accepted: 06/17/2018] [Indexed: 01/14/2023]
Abstract
A reduction in trabecular bone mass is often associated with an increase in marrow fat in osteoporotic bones. The molecular mechanisms underlying this inverse correlation are incompletely understood. Here, we report that mice lacking tuberous sclerosis 1 (Tsc1) in Osterix-expressing cells had a significant decrease in trabecular bone mass characterized by decreased osteoblastogenesis, increased osteoclastogenesis, and increased bone marrow adiposity in vivo. In vitro study showed that Tsc1-deficient bone marrow stromal cells (BMSCs) had decreased proliferation, decreased osteogenic differentiation, and increased adipogenic differentiation in association with the downregulation of Wnt/β-catenin signaling. Mechanistically, TSC1 deficiency led to autophagy suppression and consequent Notch1 protein increase, which mediated the GSK3β-independent β-catenin degradation. Together, our results indicate that Tsc1 controls the balance between osteoblast and adipocyte differentiation of BMSCs. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Han Kyoung Choi
- Department of Biologic and Materials Sciences and Division of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Hebao Yuan
- Department of Biologic and Materials Sciences and Division of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Fang Fang
- Department of Biologic and Materials Sciences and Division of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Xiaoxi Wei
- Department of Biologic and Materials Sciences and Division of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA
- Department of Orthodontics, Jilin University School and Hospital of Stomatology, Changchun, Jilin, China
| | - Lu Liu
- Department of Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Qing Li
- Department of Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Fei Liu
- Department of Biologic and Materials Sciences and Division of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA
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mTORC1 signaling suppresses Wnt/β-catenin signaling through DVL-dependent regulation of Wnt receptor FZD level. Proc Natl Acad Sci U S A 2018; 115:E10362-E10369. [PMID: 30297426 DOI: 10.1073/pnas.1808575115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Wnt/β-catenin signaling plays pivotal roles in cell proliferation and tissue homeostasis by maintaining somatic stem cell functions. The mammalian target of rapamycin (mTOR) signaling functions as an integrative rheostat that orchestrates various cellular and metabolic activities that shape tissue homeostasis. Whether these two fundamental signaling pathways couple to exert physiological functions still remains mysterious. Using a genome-wide CRISPR-Cas9 screening, we discover that mTOR complex 1 (mTORC1) signaling suppresses canonical Wnt/β-catenin signaling. Deficiency in tuberous sclerosis complex 1/2 (TSC1/2), core negative regulators of mTORC1 activity, represses Wnt/β-catenin target gene expression, which can be rescued by RAD001. Mechanistically, mTORC1 signaling regulates the cell surface level of Wnt receptor Frizzled (FZD) in a Dishevelled (DVL)-dependent manner by influencing the association of DVL and clathrin AP-2 adaptor. Sustained mTORC1 activation impairs Wnt/β-catenin signaling and causes loss of stemness in intestinal organoids ex vivo and primitive intestinal progenitors in vivo. Wnt/β-catenin-dependent liver metabolic zonation gene expression program is also down-regulated by mTORC1 activation. Our study provides a paradigm that mTORC1 signaling cell autonomously regulates Wnt/β-catenin pathway to influence stem cell maintenance.
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Amair-Pinedo F, Matos I, Saurí T, Hernando J, Capdevila J. The Treatment Landscape and New Opportunities of Molecular Targeted Therapies in Gastroenteropancreatic Neuroendocrine Tumors. Target Oncol 2018; 12:757-774. [PMID: 29143176 DOI: 10.1007/s11523-017-0532-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms that originate from neuroendocrine stem cells and express both neural and endocrine markers. They are found in almost every organ, and while NENs are mostly associated with slow growth, complications due to the uncontrolled secretion of active peptides, and metastatic disease, may significantly impair the quality of life and can ultimately lead to the death of affected individuals. Expanding knowledge of the genetic, epigenetic, and proteomic landscapes of NENs has led to a better understanding of their molecular pathology and consequently increased treatment options for patients. Here, we review the principal breakthroughs in NEN treatment management, owing largely to omics technologies over the last few years, current recommendations of systemic treatment, and ongoing research into the identification of predictive and response biomarkers based on molecular targeted therapies.
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Affiliation(s)
| | - Ignacio Matos
- Vall d'Hebron University Hospital, Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Tamara Saurí
- Vall d'Hebron University Hospital, Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Jorge Hernando
- Vall d'Hebron University Hospital, Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Jaume Capdevila
- Vall d'Hebron University Hospital, Barcelona, Spain. .,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain.
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Scieuzo C, Nardiello M, Salvia R, Pezzi M, Chicca M, Leis M, Bufo SA, Vinson SB, Rao A, Vogel H, Falabella P. Ecdysteroidogenesis and development in Heliothis virescens (Lepidoptera: Noctuidae): Focus on PTTH-stimulated pathways. JOURNAL OF INSECT PHYSIOLOGY 2018; 107:57-67. [PMID: 29454612 DOI: 10.1016/j.jinsphys.2018.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Post-embryonic development and molting in insects are regulated by endocrine changes, including prothoracicotropic hormone (PTTH)-stimulated ecdysone secretion by the prothoracic glands (PGs). In Lepidoptera, two pathways are potentially involved in PTTH-stimulated ecdysteroidogenesis, mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/protein kinase B/target of rapamycin (PI3K/Akt/TOR). We investigated the potential roles of both these pathways in Heliothis virescens ecdysteroidogenesis. We identified putative proteins belonging to MAPK and PI3K/Akt/TOR signaling cascades, using transcriptomic analyses of PGs from last (fifth) instar larvae. Using western blots, we measured the phosphorylation of 4E-BP and S6K proteins, the main targets of TOR, following the in vitro exposure of PGs to brain extract containing PTTH (hereafter referred to as PTTH) and/or the inhibitors of MAPK (U0126), PI3K (LY294002) or TOR (rapamycin). Next, we measured ecdysone production, under the same experimental conditions, by enzyme immunoassay (EIA). We found that in Heliothis virescens last instar larvae, both pathways modulated PTTH-stimulated ecdysteroidogenesis. Finally, we analyzed the post-embryonic development of third and fourth instar larvae fed on diet supplemented with rapamycin, in order to better understand the role of the TOR pathway in larval growth. When rapamycin was added to the diet of larvae, the onset of molting was delayed, the growth rate was reduced and abnormally small larvae/pupae with high mortality rates resulted. In larvae fed on diet supplemented with rapamycin, the growth of PGs was suppressed, and ecdysone production and secretion were inhibited. Overall, the in vivo and in vitro results demonstrated that, similarly to Bombyx mori, MAPK and PI3K/Akt/TOR pathways are involved in PTTH signaling-stimulated ecdysteroidogenesis, and indicated the important role of TOR protein in H. virescens systemic growth.
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Affiliation(s)
- Carmen Scieuzo
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Marisa Nardiello
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Rosanna Salvia
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Marco Pezzi
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, Ferrara 44121, Italy
| | - Milvia Chicca
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, Ferrara 44121, Italy
| | - Marilena Leis
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, Ferrara 44121, Italy
| | - Sabino A Bufo
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - S Bradleigh Vinson
- Department of Entomology, Texas A&M University, 370 Olsen Blvd, College Station, TX 77843-2475, USA
| | - Asha Rao
- Department of Biology, 3258 Texas A&M University, College Station, Texas 77843, USA
| | - Heiko Vogel
- Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Patrizia Falabella
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy.
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35
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Abstract
Cellular signaling pathways are often interconnected. They accurately and efficiently regulate essential cell functions such as protein synthesis, cell growth, and survival. The target of rapamycin (TOR) signaling pathway and the endoplasmic reticulum (ER) stress response pathway regulate similar cellular processes. However, the crosstalk between them has not been appreciated until recently and the detailed mechanisms remain unclear. Here, we show that ER stress-inducing drugs activate the TOR signaling pathway in S2R+ Drosophila cells. Activating transcription factor 6 (Atf6), a major stress-responsive ER transmembrane protein, is responsible for ER stress-induced TOR activation. Supporting the finding, we further show that knocking down of both site-1/2 proteases (S1P/S2P), Atf6 processing enzymes, are necessary to connect the two pathways.
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36
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Crisafulli U, Xavier AM, Dos Santos FB, Cambiaghi TD, Chang SY, Porcionatto M, Castilho BA, Malnic B, Glezer I. Topical Dexamethasone Administration Impairs Protein Synthesis and Neuronal Regeneration in the Olfactory Epithelium. Front Mol Neurosci 2018; 11:50. [PMID: 29559887 PMCID: PMC5845685 DOI: 10.3389/fnmol.2018.00050] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/06/2018] [Indexed: 11/13/2022] Open
Abstract
Chronic inflammatory process in the nasal mucosa is correlated with poor smell perception. Over-activation of immune cells in the olfactory epithelium (OE) is generally associated with loss of olfactory function, and topical steroidal anti-inflammatory drugs have been largely used for treating such condition. Whether this therapeutic strategy could directly affect the regenerative process in the OE remains unclear. In this study, we show that nasal topical application of dexamethasone (DEX; 200 or 800 ng/nostril), a potent synthetic anti-inflammatory steroid, attenuates OE lesion caused by Gram-negative bacteria lipopolysaccharide (LPS) intranasal infusion. In contrast, repeated DEX (400 ng/nostril) local application after lesion establishment limited the regeneration of olfactory sensory neurons after injury promoted by LPS or methimazole. Remarkably, DEX effects were observed when the drug was infused as 3 consecutive days regimen. The anti-inflammatory drug does not induce OE progenitor cell death, however, disturbance in mammalian target of rapamycin downstream signaling pathway and impairment of protein synthesis were observed during the course of DEX treatment. In addition, in vitro studies conducted with OE neurospheres in the absence of an inflammatory environment showed that glucocorticoid receptor engagement directly reduces OE progenitor cells proliferation. Our results suggest that DEX can interfere with the intrinsic regenerative cellular mechanisms of the OE, raising concerns on the use of topical anti-inflammatory steroids as a risk factor for progressive olfactory function impairment.
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Affiliation(s)
- Umberto Crisafulli
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.,Department of Biochemistry, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - André M Xavier
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Fabiana B Dos Santos
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Tavane D Cambiaghi
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Seo Y Chang
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Marimélia Porcionatto
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Beatriz A Castilho
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Bettina Malnic
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Isaias Glezer
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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37
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Cong XX, Rao XS, Lin JX, Liu XC, Zhang GA, Gao XK, He MY, Shen WL, Fan W, Pioletti D, Zheng LL, Liu HH, Yin Z, Low BC, Schweitzer R, Ouyang H, Chen X, Zhou YT. Activation of AKT-mTOR Signaling Directs Tenogenesis of Mesenchymal Stem Cells. Stem Cells 2018; 36:527-539. [PMID: 29315990 DOI: 10.1002/stem.2765] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 01/28/2023]
Abstract
Tendon repair is a clinical challenge because of the limited understanding on tenogenesis. The synthesis of type I collagen (Collagen I) and other extracellular matrix are essential for tendon differentiation and homeostasis. Current studies on tenogenesis focused mostly on the tenogenic transcriptional factors while the signaling controlling tenogenesis on translational level remains largely unknown. Here, we showed that mechanistic target of rapamycin (mTOR) signaling was activated by protenogenic growth factor, transforming growth factors beta1, and insulin-like growth factor-I. The expression of mTOR was upregulated during tenogenesis of mesenchymal stem cells (MSCs). Moreover, mTOR was downregulated in human tendinopathy tissues and was inactivated upon statin treatment. Both inhibition and depletion of AKT or mTOR significantly reduced type I collagen production and impaired tenogenesis of MSCs. Tendon specific-ablation of mTOR resulted in tendon defect and reduction of Collagen I. However, there is no evident downregulation of tendon associated collagens at the transcription level. Our study demonstrated that AKT-mTOR axis is a key mediator of tendon differentiation and provided a novel therapeutic target for tendinopathy and tendon injuries. Stem Cells 2018;36:527-539.
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Affiliation(s)
- Xiao Xia Cong
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Xi Sheng Rao
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Jun Xin Lin
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Xiao Ceng Liu
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Guang An Zhang
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Xiu Kui Gao
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Min Yi He
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Wei Liang Shen
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China.,Department of Orthopaedic Surgery, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Wei Fan
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Dominique Pioletti
- Laboratory of Biomechanical Orthopedics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Li Ling Zheng
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Huan Huan Liu
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Zi Yin
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China
| | - Boon Chuan Low
- Mechanobiology Institute, Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ronen Schweitzer
- Portland Shriners Hospital, Oregon Health and Science University, Portland, Oregon, USA
| | - Hongwei Ouyang
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China.,China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, People's Republic of China
| | - Xiao Chen
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China.,China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, People's Republic of China
| | - Yi Ting Zhou
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Hangzhou, People's Republic of China.,China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, People's Republic of China
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38
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Guduru SKR, Arya P. Synthesis and biological evaluation of rapamycin-derived, next generation small molecules. MEDCHEMCOMM 2018; 9:27-43. [PMID: 30108899 PMCID: PMC6072512 DOI: 10.1039/c7md00474e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Accepted: 11/21/2017] [Indexed: 12/20/2022]
Abstract
Over the years, rapamycin has attracted serious attention due to its remarkable biological properties and as a potent inhibitor of the mammalian target of rapamycin (mTOR) protein through its binding with FKBP-12. Several efficient strategies that utilize synthetic and biosynthetic approaches have been utilized to develop small molecule rapamycin analogs or for synthesizing hybrid compounds containing a partial rapamycin structure to improve pharmacokinetic properties. Herein, we report selected case studies related to the synthesis of rapamycin-derived compounds and hybrid molecules to explore their biological properties.
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Affiliation(s)
- Shiva Krishna Reddy Guduru
- Center for Drug Discovery , Department of Pharmacology and Chemical Biology , Baylor College of Medicine , One Baylor Plaza , Houston , Texas 77030 , USA . ; ; Tel: +1 713 798 8794
- Department of Pharmacology and Chemical Biology , Baylor College of Medicine , One Baylor Plaza , Houston , Texas 77030 , USA
| | - Prabhat Arya
- Chemistry and Chemical Biology , Dr. Reddy's Institute of Life Sciences (DRILS) , University of Hyderabad Campus , Hyderabad 500046 , India
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39
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Kamaladevi A, Balamurugan K. Global Proteomics Revealed Klebsiella pneumoniae Induced Autophagy and Oxidative Stress in Caenorhabditis elegans by Inhibiting PI3K/AKT/mTOR Pathway during Infection. Front Cell Infect Microbiol 2017; 7:393. [PMID: 28932706 PMCID: PMC5592217 DOI: 10.3389/fcimb.2017.00393] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/22/2017] [Indexed: 01/29/2023] Open
Abstract
The enterobacterium, Klebsiella pneumoniae invades the intestinal epithelium of humans by interfering with multiple host cell response. To uncover a system-level overview of host response during infection, we analyzed the global dynamics of protein profiling in Caenorhabditis elegans using quantitative proteomics approach. Comparison of protein samples of nematodes exposed to K. pneumoniae for 12, 24, and 36 h by 2DE revealed several changes in host proteome. A total of 266 host-encoded proteins were identified by 2DE MALDI-MS/MS and LC-MS/MS and the interacting partners of the identified proteins were predicted by STRING 10.0 analysis. In order to understand the interacting partners of regulatory proteins with similar or close pI ranges, a liquid IEF was performed and the isolated fractions containing proteins were identified by LC-MS/MS. Functional bioinformatics analysis on identified proteins deciphered that they were mostly related to the metabolism, dauer formation, apoptosis, endocytosis, signal transduction, translation, developmental, and reproduction process. Gene enrichment analysis suggested that the metabolic process as the most overrepresented pathway regulated against K. pneumoniae infection. The dauer-like formation in infected C. elegans along with intestinal atrophy and ROS during the physiological analysis indicated that the regulation of metabolic pathway is probably through the involvement of mTOR. Immunoblot analysis supported the above notion that the K. pneumoniae infection induced protein mis-folding in host by involving PI3Kinase/AKT-1/mTOR mediated pathway. Furthermore, the susceptibility of pdi-2, akt-1, and mTOR C. elegans mutants confirmed the role and involvement of PI3K/AKT/mTOR pathway in mediating protein mis-folding which appear to be translating the vulnerability of host defense toward K. pneumoniae infection.
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40
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Ohhara Y, Kobayashi S, Yamanaka N. Nutrient-Dependent Endocycling in Steroidogenic Tissue Dictates Timing of Metamorphosis in Drosophila melanogaster. PLoS Genet 2017; 13:e1006583. [PMID: 28121986 PMCID: PMC5298324 DOI: 10.1371/journal.pgen.1006583] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 02/08/2017] [Accepted: 01/13/2017] [Indexed: 01/09/2023] Open
Abstract
Many animals have an intrinsic growth checkpoint during juvenile development, after which an irreversible decision is made to upregulate steroidogenesis, triggering the metamorphic juvenile-to-adult transition. However, a molecular process underlying such a critical developmental decision remains obscure. Here we show that nutrient-dependent endocycling in steroidogenic cells provides the machinery necessary for irreversible activation of metamorphosis in Drosophila melanogaster. Endocycle progression in cells of the prothoracic gland (PG) is tightly coupled with the growth checkpoint, and block of endocycle in PG cells causes larval developmental arrest due to reduction in biosynthesis of the steroid hormone ecdysone. Moreover, inhibition of the nutrient sensor target of rapamycin (TOR) in the PG during the checkpoint period causes endocycle inhibition and developmental arrest, which can be rescued by inducing additional rounds of endocycles by Cyclin E. We propose that a TOR-mediated cell cycle checkpoint in steroidogenic tissue provides a systemic growth checkpoint for reproductive maturation. Onset of sexual maturation constitutes a point of no return in animals; once this life-changing decision is made, upregulation of steroidogenesis leads to irreversible juvenile-to-adult transition in humans and insects alike. While nutrient signals contributing to this decision-making process have been well studied, molecular events that ultimately determine its precise timing remain a mystery. We report here that nutrient-dependent endoreplication, the replication of genomic DNA without cell division, in steroidogenic cells functions as an intrinsic timer, whereby degree of polyploidy sets the timing of reproductive maturation (i.e. metamorphosis) in fruit flies. The cumulative and irreversible nature of endoreplication thus provides an intrinsic molecular machinery underlying the irreversible decision-making process, which may be widely leveraged as a fundamental developmental timing mechanism.
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Affiliation(s)
- Yuya Ohhara
- Department of Entomology, Institute for Integrative Genome Biology, Center for Disease Vector Research, University of California, Riverside, Riverside, California, United States of America
| | - Satoru Kobayashi
- Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Naoki Yamanaka
- Department of Entomology, Institute for Integrative Genome Biology, Center for Disease Vector Research, University of California, Riverside, Riverside, California, United States of America
- * E-mail:
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41
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Gharibi B, Ghuman M, Hughes FJ. DDIT4 regulates mesenchymal stem cell fate by mediating between HIF1α and mTOR signalling. Sci Rep 2016; 6:36889. [PMID: 27876894 PMCID: PMC5120275 DOI: 10.1038/srep36889] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 10/24/2016] [Indexed: 12/05/2022] Open
Abstract
Stem cell fate decisions to remain quiescent, self-renew or differentiate are largely governed by the interplay between extracellular signals from the niche and the cell intrinsic signal cascades and transcriptional programs. Here we demonstrate that DNA Damage Inducible Transcript 4 (DDIT4) acts as a link between HIF1α and mTOR signalling and regulation of adult stem cell fate. Global gene expression analysis of mesenchymal stem cells (MSC) derived from single clones and live RNA cell sorting showed a direct correlation between DDIT4 and differentiation potentials of MSC. Loss and gain of function analysis demonstrated that DDIT4 activity is directly linked to regulation of mTOR signalling, expression of pluripotency genes and differentiation. Further we demonstrated that DDIT4 exert these effects down-stream to HIF1α. Our findings provide an insight in regulation of adult stem cells homeostasis by two major pathways with opposing functions to coordinate between states of self-renewal and differentiation.
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Affiliation(s)
- Borzo Gharibi
- Division of Tissue Engineering and Biophotonics, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, SE1 9RT. UK
| | - Mandeep Ghuman
- Division of Tissue Engineering and Biophotonics, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, SE1 9RT. UK
| | - Francis J Hughes
- Division of Tissue Engineering and Biophotonics, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, SE1 9RT. UK
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42
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Caron A, Richard D. Neuronal systems and circuits involved in the control of food intake and adaptive thermogenesis. Ann N Y Acad Sci 2016; 1391:35-53. [PMID: 27768821 DOI: 10.1111/nyas.13263] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 08/18/2016] [Accepted: 08/24/2016] [Indexed: 12/27/2022]
Abstract
With the still-growing prevalence of obesity worldwide, major efforts are made to understand the various behavioral, environmental, and genetic factors that promote excess fat gain. Obesity results from an imbalance between energy intake and energy expenditure, which emphasizes the importance of deciphering the mechanisms behind energy balance regulation to understand its physiopathology. The control of energy balance is assured by brain systems/circuits capable of generating adequate ingestive and thermogenic responses to maintain the stability of energy reserves, which implies a proper integration of the homeostatic signals that inform about the status of the energy stores. In this article, we overview the organization and functionality of key neuronal circuits or pathways involved in the control of food intake and energy expenditure. We review the role of the corticolimbic (executive and reward) and autonomic systems that integrate their activities to regulate energy balance. We also describe the mechanisms and pathways whereby homeostatic sensing is achieved in response to variations of homeostatic hormones, such as leptin, insulin, and ghrelin, while putting some emphasis on the prominent importance of the mechanistic target of the rapamycin signaling pathway in coordinating the homeostatic sensing process.
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Affiliation(s)
- Alexandre Caron
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec and Faculty of Medicine, Department of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Denis Richard
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec and Faculty of Medicine, Department of Medicine, Université Laval, Quebec City, Quebec, Canada
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43
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Yan B, Zhang Z, Jin D, Cai C, Jia C, Liu W, Wang T, Li S, Zhang H, Huang B, Lai P, Wang H, Liu A, Zeng C, Cai D, Jiang Y, Bai X. mTORC1 regulates PTHrP to coordinate chondrocyte growth, proliferation and differentiation. Nat Commun 2016; 7:11151. [PMID: 27039827 PMCID: PMC4822018 DOI: 10.1038/ncomms11151] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/24/2016] [Indexed: 12/20/2022] Open
Abstract
Precise coordination of cell growth, proliferation and differentiation is essential for the development of multicellular organisms. Here, we report that although the mechanistic target of rapamycin complex 1 (mTORC1) activity is required for chondrocyte growth and proliferation, its inactivation is essential for chondrocyte differentiation. Hyperactivation of mTORC1 via TSC1 gene deletion in chondrocytes causes uncoupling of the normal proliferation and differentiation programme within the growth plate, resulting in uncontrolled cell proliferation, and blockage of differentiation and chondrodysplasia in mice. Rapamycin promotes chondrocyte differentiation and restores these defects in mutant mice. Mechanistically, mTORC1 downstream kinase S6K1 interacts with and phosphorylates Gli2, and releases Gli2 from SuFu binding, resulting in nuclear translocation of Gli2 and transcription of parathyroid hormone-related peptide (PTHrP), a key regulator of bone development. Our findings demonstrate that dynamically controlled mTORC1 activity is crucial to coordinate chondrocyte proliferation and differentiation partially through regulating Gli2/PTHrP during endochondral bone development.
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Affiliation(s)
- Bo Yan
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Zhongmin Zhang
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Dadi Jin
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Chen Cai
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Chunhong Jia
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Wen Liu
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Ting Wang
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shengfa Li
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Haiyan Zhang
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Bin Huang
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Pinglin Lai
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Hua Wang
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Anling Liu
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Chun Zeng
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Daozhang Cai
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
| | - Yu Jiang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
| | - Xiaochun Bai
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
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44
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Sampson LL, Davis AK, Grogg MW, Zheng Y. mTOR disruption causes intestinal epithelial cell defects and intestinal atrophy postinjury in mice. FASEB J 2015; 30:1263-75. [PMID: 26631481 DOI: 10.1096/fj.15-278606] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/16/2015] [Indexed: 12/21/2022]
Abstract
Intestinal stem cells (ISCs) drive small intestinal epithelial homeostasis and regeneration. Mechanistic target of rapamycin (mTOR) regulates stem and progenitor cell metabolism and is frequently dysregulated in human disease, but its physiologic functions in the mammalian small intestinal epithelium remain poorly defined. We disrupted the genes mTOR, Rptor, Rictor, or both Rptor and Rictor in mouse ISCs, progenitors, and differentiated intestinal epithelial cells (IECs) using Villin-Cre. Mutant tissues and wild-type or heterozygous littermate controls were analyzed by histologic immunostaining, immunoblots, and proliferation assays. A total of 10 Gy irradiation was used to injure the intestinal epithelium and induce subsequent crypt regeneration. We report that mTOR supports absorptive enterocytes and secretory Paneth and goblet cell function while negatively regulating chromogranin A-positive enteroendocrine cell number. Through additional Rptor, Rictor, and Rptor/Rictor mutant mouse models, we identify mechanistic target of rapamycin complex 1 as the major IEC regulatory pathway, but mechanistic target of rapamycin complex 2 also contributes to ileal villus maintenance and goblet cell size. Homeostatic adult small intestinal crypt cell proliferation, survival, and canonical wingless-int (WNT) activity are not mTOR dependent, but Olfm4(+) ISC/progenitor population maintenance and crypt regeneration postinjury require mTOR. Overall, we conclude that mTOR regulates multiple IEC lineages and promotes stem and progenitor cell activity during intestinal epithelium repair postinjury.
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Affiliation(s)
- Leesa L Sampson
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Ashley K Davis
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Matthew W Grogg
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Yi Zheng
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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45
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Abstract
TOR (target of rapamycin) and its mammalian ortholog mTOR have been discovered in an effort to understand the mechanisms of action of the immunosuppressant drug rapamycin extracted from a bacterium of the Easter Island (Rapa Nui) soil. mTOR is a serine/threonine kinase found in two functionally distinct complexes, mTORC1 and mTORC2, which are differentially regulated by a great number of nutrients such as glucose and amino acids, energy (oxygen and ATP/AMP content), growth factors, hormones, and neurotransmitters. mTOR controls many basic cellular functions such as protein synthesis, energy metabolism, cell size, lipid metabolism, autophagy, mitochondria, and lysosome biogenesis. In addition, mTOR-controlled signaling pathways regulate many integrated physiological functions of the nervous system including neuronal development, synaptic plasticity, memory storage, and cognition. Thus it is not surprising that deregulation of mTOR signaling is associated with many neurological and psychiatric disorders. Preclinical and preliminary clinical studies indicate that inhibition of mTORC1 can be beneficial for some pathological conditions such as epilepsy, cognitive impairment, and brain tumors, whereas stimulation of mTORC1 (direct or indirect) can be beneficial for other pathologies such as depression or axonal growth and regeneration.
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Affiliation(s)
- Joël Bockaert
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
| | - Philippe Marin
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
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46
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Gharibi B, Farzadi S, Ghuman M, Hughes FJ. Inhibition of Akt/mTOR attenuates age-related changes in mesenchymal stem cells. Stem Cells 2015; 32:2256-66. [PMID: 24659476 DOI: 10.1002/stem.1709] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 02/01/2014] [Indexed: 01/10/2023]
Abstract
The decline in mesenchymal stem cell (MSC) self-renewal and function with aging contributes to diseases associated with impaired osteogenesis. MSC donor age in prolonged culture also limits the therapeutic potential of these cells for tissue engineering and regenerative medicine. Here, we demonstrate an intervention to preserve the immature state MSC and consequently maintain self-renewal and differentiation capacity during in vitro aging. We showed that blocking of phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (mTOR) prevents the development of an age-related phenotype and maintains MSC morphology of early passage cells with high clonogenic frequency and enhanced proliferative capacity. MSC cultured in the presence of inhibitors of Akt or mTOR also robustly maintain their osteogenic potential, that is otherwise lost during in vitro aging. We further report that these effects may be mediated by induction of expression of pluripotency genes Nanog and Oct-4 and by the reduction in the production of cytoplasmic reactive oxygen species (ROS). Additionally, loss of Akt/mTOR and ROS was accompanied with lower levels of DNA damage. These results provide an insight into mechanisms involved in MSC aging and suggest possible interventions to maintain quiescence and function of MSC prior to in vivo transplantation or as pharmacological agents in diseases associated with loss of MSC function.
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Affiliation(s)
- Borzo Gharibi
- Department of Periodontology, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, United Kingdom
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Li SF, Tang JJ, Chen J, Zhang P, Wang T, Chen TY, Yan B, Huang B, Wang L, Huang MJ, Zhang ZM, Jin DD. Regulation of bone formation by baicalein via the mTORC1 pathway. Drug Des Devel Ther 2015; 9:5169-83. [PMID: 26392752 PMCID: PMC4572734 DOI: 10.2147/dddt.s81578] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Osteoporosis is a systemic skeletal disease that is characterized by low bone density and microarchitectural deterioration of bone tissue. The increasing prevalence of osteoporosis has attracted much attention. In this study, MC3T3-E1 pre-osteoblasts were treated with the natural compound, baicalein (0.1 μmol/L, 1 μmol/L, 10 μmol/L), to stimulate differentiation over a 14-day period. In addition, a canonical ovariectomized (OVX) mouse model was used to investigate the effect of 3-month baicalein treatment (10 mg/kg per day) in preventing postmenopausal osteoporosis. In vitro, we found that baicalein induced activation of alkaline phosphatase, stimulated the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, and induced expression of osteoblast differentiation markers, ie, osteocalcin, osterix, collagen Iα1, and runt-related transcription factor 2 (RUNX2), in osteoblasts. In vivo, several bone parameters, including trabecular thickness, trabecular bone mineral density, and trabecular number, in the distal femoral metaphysis were significantly increased in OVX mice treated intragastrically with baicalein for 3 months compared with OVX mice that were not treated with baicalein. We also found that expression of osteocalcin and RUNX2 was decreased in primary ossified tissue from the OVX group, and baicalein increased the levels of osteocalcin and RUNX2 in OVX mice. These data suggest that baicalein can stimulate MC3T3-E1 cells to differentiate into osteoblasts via activation of the mTORC1 signaling pathway, which includes protein kinases and transcription factors such as P-4E/BP1 and P-S6K1.
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Affiliation(s)
- Sheng-fa Li
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Jia-jun Tang
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Jian Chen
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China ; Three Gorges Central Hospital of Chongqing, Chongqing, People's Republic of China
| | - Pei Zhang
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Ting Wang
- Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Tian-yu Chen
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Bo Yan
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Bin Huang
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Liang Wang
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Min-jun Huang
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Zhong-min Zhang
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Da-di Jin
- Academy of Orthopedics of Guangdong Province, Guangzhou, People's Republic of China ; Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
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Ruiz de Garibay G, Herranz C, Llorente A, Boni J, Serra-Musach J, Mateo F, Aguilar H, Gómez-Baldó L, Petit A, Vidal A, Climent F, Hernández-Losa J, Cordero Á, González-Suárez E, Sánchez-Mut JV, Esteller M, Llatjós R, Varela M, López JI, García N, Extremera AI, Gumà A, Ortega R, Plà MJ, Fernández A, Pernas S, Falo C, Morilla I, Campos M, Gil M, Román A, Molina-Molina M, Ussetti P, Laporta R, Valenzuela C, Ancochea J, Xaubet A, Casanova Á, Pujana MA. Lymphangioleiomyomatosis Biomarkers Linked to Lung Metastatic Potential and Cell Stemness. PLoS One 2015; 10:e0132546. [PMID: 26167915 PMCID: PMC4500593 DOI: 10.1371/journal.pone.0132546] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 06/17/2015] [Indexed: 12/23/2022] Open
Abstract
Lymphangioleiomyomatosis (LAM) is a rare lung-metastasizing neoplasm caused by the proliferation of smooth muscle-like cells that commonly carry loss-of-function mutations in either the tuberous sclerosis complex 1 or 2 (TSC1 or TSC2) genes. While allosteric inhibition of the mechanistic target of rapamycin (mTOR) has shown substantial clinical benefit, complementary therapies are required to improve response and/or to treat specific patients. However, there is a lack of LAM biomarkers that could potentially be used to monitor the disease and to develop other targeted therapies. We hypothesized that the mediators of cancer metastasis to lung, particularly in breast cancer, also play a relevant role in LAM. Analyses across independent breast cancer datasets revealed associations between low TSC1/2 expression, altered mTOR complex 1 (mTORC1) pathway signaling, and metastasis to lung. Subsequently, immunohistochemical analyses of 23 LAM lesions revealed positivity in all cases for the lung metastasis mediators fascin 1 (FSCN1) and inhibitor of DNA binding 1 (ID1). Moreover, assessment of breast cancer stem or luminal progenitor cell biomarkers showed positivity in most LAM tissue for the aldehyde dehydrogenase 1 (ALDH1), integrin-ß3 (ITGB3/CD61), and/or the sex-determining region Y-box 9 (SOX9) proteins. The immunohistochemical analyses also provided evidence of heterogeneity between and within LAM cases. The analysis of Tsc2-deficient cells revealed relative over-expression of FSCN1 and ID1; however, Tsc2-deficient cells did not show higher sensitivity to ID1-based cancer inhibitors. Collectively, the results of this study reveal novel LAM biomarkers linked to breast cancer metastasis to lung and to cell stemness, which in turn might guide the assessment of additional or complementary therapeutic opportunities for LAM.
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Affiliation(s)
- Gorka Ruiz de Garibay
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Carmen Herranz
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Alicia Llorente
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Jacopo Boni
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Jordi Serra-Musach
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Francesca Mateo
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Helena Aguilar
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Laia Gómez-Baldó
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Anna Petit
- Department of Pathology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - August Vidal
- Department of Pathology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Fina Climent
- Department of Pathology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | | | - Álex Cordero
- Cancer Epigenetics and Biology Program, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Eva González-Suárez
- Cancer Epigenetics and Biology Program, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - José Vicente Sánchez-Mut
- Cancer Epigenetics and Biology Program, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Manel Esteller
- Cancer Epigenetics and Biology Program, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
- Department of Physiological Sciences II, School of Medicine, University of Barcelona, Barcelona, Catalonia, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain
| | - Roger Llatjós
- Department of Pathology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Mar Varela
- Department of Pathology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - José Ignacio López
- Cruces University Hospital, BioCruces Research Institute, University of the Basque Country, Barakaldo, Spain
| | - Nadia García
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Ana I. Extremera
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Anna Gumà
- Department of Radiology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Raúl Ortega
- Department of Radiology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - María Jesús Plà
- Department of Gynecology, University Hospital of Bellvitge, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Adela Fernández
- Department of Medical Oncology, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Sònia Pernas
- Department of Medical Oncology, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Catalina Falo
- Department of Medical Oncology, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Idoia Morilla
- Department of Medical Oncology, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Miriam Campos
- Department of Medical Oncology, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Miguel Gil
- Department of Medical Oncology, Breast Cancer Unit, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
| | - Antonio Román
- Department of Pulmonology, Lung Transplant Unit, Lymphangioleiomyomatosis (LAM) Clinic, Vall d'Hebron University Hospital, Barcelona, Catalonia, Spain
| | - María Molina-Molina
- Department of Pneumology, University Hospital of Bellvitge, Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
- Biomedical Research Centre Network for Respiratory Diseases (CIBERES), Madrid, Spain
| | - Piedad Ussetti
- Department of Pneumology, University Hospital Clínica Puerta del Hierro, Madrid, Spain
| | - Rosalía Laporta
- Department of Pneumology, University Hospital Clínica Puerta del Hierro, Madrid, Spain
| | - Claudia Valenzuela
- Department of Pneumology, Instituto de Investigación Sanitaria La Princesa, Hospital La Princesa, Madrid, Spain
| | - Julio Ancochea
- Department of Pneumology, Instituto de Investigación Sanitaria La Princesa, Hospital La Princesa, Madrid, Spain
| | - Antoni Xaubet
- Biomedical Research Centre Network for Respiratory Diseases (CIBERES), Madrid, Spain
- Department of Pneumology, Hospital Clinic of Barcelona, Agusti Pi Suñer Biomedical Research Institute (IDIBAPS), Barcelona, Catalonia, Spain
| | | | - Miguel Angel Pujana
- Program Against Cancer Therapeutic Resistance (ProCURE), Breast Cancer and Systems Biology, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL), L’Hospitalet del Llobregat, Catalonia, Spain
- * E-mail:
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Liu D, Zhang Y, Gharavi R, Park HR, Lee J, Siddiqui S, Telljohann R, Nassar MR, Cutler RG, Becker KG, Mattson MP. The mitochondrial uncoupler DNP triggers brain cell mTOR signaling network reprogramming and CREB pathway up-regulation. J Neurochem 2015; 134:677-92. [PMID: 26010875 DOI: 10.1111/jnc.13176] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 05/07/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022]
Abstract
Mitochondrial metabolism is highly responsive to nutrient availability and ongoing activity in neuronal circuits. The molecular mechanisms by which brain cells respond to an increase in cellular energy expenditure are largely unknown. Mild mitochondrial uncoupling enhances cellular energy expenditure in mitochondria and can be induced with 2,4-dinitrophenol (DNP), a proton ionophore previously used for weight loss. We found that DNP treatment reduces mitochondrial membrane potential, increases intracellular Ca(2+) levels and reduces oxidative stress in cerebral cortical neurons. Gene expression profiling of the cerebral cortex of DNP-treated mice revealed reprogramming of signaling cascades that included suppression of the mammalian target of rapamycin (mTOR) and insulin--PI3K - MAPK pathways, and up-regulation of tuberous sclerosis complex 2, a negative regulator of mTOR. Genes encoding proteins involved in autophagy processes were up-regulated in response to DNP. CREB (cAMP-response element-binding protein) signaling, Arc and brain-derived neurotrophic factor, which play important roles in synaptic plasticity and adaptive cellular stress responses, were up-regulated in response to DNP, and DNP-treated mice exhibited improved performance in a test of learning and memory. Immunoblot analysis verified that key DNP-induced changes in gene expression resulted in corresponding changes at the protein level. Our findings suggest that mild mitochondrial uncoupling triggers an integrated signaling response in brain cells characterized by reprogramming of mTOR and insulin signaling, and up-regulation of pathways involved in adaptive stress responses, molecular waste disposal, and synaptic plasticity. Physiological bioenergetic challenges such as exercise and fasting can enhance neuroplasticity and protect neurons against injury and neurodegeneration. Here, we show that the mitochondrial uncoupling agent 2,4-dinitrophenol (DNP) elicits adaptive signaling responses in the cerebral cortex involving activation of Ca(2+) -CREB and autophagy pathways, and inhibition of mTOR and insulin signaling pathways. The molecular reprogramming induced by DNP, which is similar to that of exercise and fasting, is associated with improved learning and memory, suggesting potential therapeutic applications for DNP.
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Affiliation(s)
- Dong Liu
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Yongqing Zhang
- Gene Expression and Genomics Unit, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Robert Gharavi
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Hee Ra Park
- Department of Pharmacy, College of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan, Korea
| | - Jaewon Lee
- Department of Pharmacy, College of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan, Korea
| | - Sana Siddiqui
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Richard Telljohann
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Matthew R Nassar
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Roy G Cutler
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Kevin G Becker
- Gene Expression and Genomics Unit, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA
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Crino PB. mTOR signaling in epilepsy: insights from malformations of cortical development. Cold Spring Harb Perspect Med 2015; 5:5/4/a022442. [PMID: 25833943 DOI: 10.1101/cshperspect.a022442] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Over the past decade enhanced activation of the mammalian target of rapamycin (mTOR)-signaling cascade has been identified in focal malformations of cortical development (MCD) subtypes, which have been collectively referred to as "mTORopathies." Mutations in mTOR regulatory genes (e.g., TSC1, TSC2, AKT3, DEPDC5) have been associated with several focal MCD highly associated with epilepsy such as tuberous sclerosis complex (TSC), hemimegalencephaly (HME; brain malformation associated with dramatic enlargement of one brain hemisphere), and cortical dysplasia. mTOR plays important roles in the regulation of cell division, growth, and survival, and, thus, aberrant activation of the cascade during cortical development can cause dramatic alterations in cell size, cortical lamination, and axon and dendrite outgrowth often observed in focal MCD. Although it is widely believed that structural alterations induced by hyperactivated mTOR signaling are critical for epileptogenesis, newer evidence suggests that mTOR activation on its own may enhance neuronal excitability. Clinical trials with mTOR inhibitors have shown efficacy in the treatment of seizures associated with focal MCD.
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Affiliation(s)
- Peter B Crino
- Shriners Hospital Pediatric Research Center and Department of Neurology, Temple University, Philadelphia, Pennsylvania 19140
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