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Traber MG. Deciphering the enigma of the function of alpha-tocopherol as a vitamin. Free Radic Biol Med 2024; 221:64-74. [PMID: 38754744 DOI: 10.1016/j.freeradbiomed.2024.05.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/18/2024]
Abstract
α-Tocopherol (α-T) is a vitamin, but the reasons for the α-T requirement are controversial. Given that α-T deficiency was first identified in embryos, we studied to the premier model of vertebrate embryo development, the zebrafish embryo. We developed an α-T-deficient diet for zebrafish and used fish consuming this diet to produce α-T deficient (E-) embryos. We showed that α-T deficiency causes increased lipid peroxidation, leading to metabolic dysregulation that impacts both biochemical and morphological changes at very early stages in development. These changes occur at an early developmental window, which takes place prior to an analogous time to when a human knows she is pregnant. We found that α-T limits the chain reaction of lipid peroxidation and protects metabolic pathways and integrated gene expression networks that control embryonic development. Importantly, not only is α-T critical during early development, but the neurodevelopmental process is highly dependent on α-T trafficking by the α-T transfer protein (TTPa). Data from both gene expression and evaluation of the metabolome in E- embryos suggest that the activity of the mechanistic Target of Rapamycin (mTOR) signaling pathway is dysregulated-mTOR is a master regulatory mechanism, which controls both metabolism and neurodevelopment. Our findings suggest that TTPa is needed not only for regulation of plasma α-T in adults but is a key regulator during embryogenesis.
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Affiliation(s)
- Maret G Traber
- Linus Pauling Institute, Oregon State University, Corvallis, 97330, OR, USA.
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2
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Zhang P, Zhang H, Li C, Yang B, Feng X, Cao J, Du W, Shahzad M, Khan A, Sun SC, Zhao X. Effects of Regulating Hippo and Wnt on the Development and Fate Differentiation of Bovine Embryo. Int J Mol Sci 2024; 25:3912. [PMID: 38612721 PMCID: PMC11011455 DOI: 10.3390/ijms25073912] [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: 03/03/2024] [Revised: 03/29/2024] [Accepted: 03/29/2024] [Indexed: 04/14/2024] Open
Abstract
The improvement of in vitro embryo development is a gateway to enhance the output of assisted reproductive technologies. The Wnt and Hippo signaling pathways are crucial for the early development of bovine embryos. This study investigated the development of bovine embryos under the influence of a Hippo signaling agonist (LPA) and a Wnt signaling inhibitor (DKK1). In this current study, embryos produced in vitro were cultured in media supplemented with LPA and DKK1. We comprehensively analyzed the impact of LPA and DKK1 on various developmental parameters of the bovine embryo, such as blastocyst formation, differential cell counts, YAP fluorescence intensity and apoptosis rate. Furthermore, single-cell RNA sequencing (scRNA-seq) was employed to elucidate the in vitro embryonic development. Our results revealed that LPA and DKK1 improved the blastocyst developmental potential, total cells, trophectoderm (TE) cells and YAP fluorescence intensity and decreased the apoptosis rate of bovine embryos. A total of 1203 genes exhibited differential expression between the control and LPA/DKK1-treated (LD) groups, with 577 genes upregulated and 626 genes downregulated. KEGG pathway analysis revealed significant enrichment of differentially expressed genes (DEGs) associated with TGF-beta signaling, Wnt signaling, apoptosis, Hippo signaling and other critical developmental pathways. Our study shows the role of LPA and DKK1 in embryonic differentiation and embryo establishment of pregnancy. These findings should be helpful for further unraveling the precise contributions of the Hippo and Wnt pathways in bovine trophoblast formation, thus advancing our comprehension of early bovine embryo development.
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Affiliation(s)
- Peipei Zhang
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hang Zhang
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Chongyang Li
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Baigao Yang
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Xiaoyi Feng
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Jianhua Cao
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Weihua Du
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Muhammad Shahzad
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
| | - Adnan Khan
- Genome Analysis Laboratory of the Ministry of Agriculture, Agriculture Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xueming Zhao
- Institute of Animal Sciences (IAS), Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan Western Road, Haidian District, Beijing 100193, China
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3
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Li X, Li G, Cui S, Hou Y, Li Z, Yan Z, Huang T, Zhao T, Su H, Zhou B, Zhang J, Ao R, Zhao H, Qiu Y, Liu Z, Xie J. Arsenic disturbs neural tube closure involving AMPK/PKB-mTORC1-mediated autophagy in mice. Food Chem Toxicol 2024; 186:114538. [PMID: 38387523 DOI: 10.1016/j.fct.2024.114538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/01/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Arsenic exposure is a significant risk factor for folate-resistant neural tube defects (NTDs), but the potential mechanism is unclear. In this study, a mouse model of arsenic-induced NTDs was established to investigate how arsenic affects early neurogenesis leading to malformations. The results showed that in utero exposure to arsenic caused a decline in the normal embryos, an elevated embryo resorption, and a higher incidence of malformed embryos. Cranial and spinal deformities were the main malformation phenotypes observed. Meanwhile, arsenic-induced NTDs were accompanied by an oxidant/antioxidant imbalance manifested by elevated levels of reactive oxygen species (ROS) and decreased antioxidant activities. In addition, changes in the expression of autophagy-related genes and proteins (ULK1, Atg5, LC3B, p62) as well as an increase in autophagosomes were observed in arsenic-induced aberrant brain vesicles. Also, the components of the upstream pathway regulating autophagy (AMPK, PKB, mTOR, Raptor) were altered accordingly after arsenic exposure. Collectively, our findings propose a mechanism for arsenic-induced NTDs involving AMPK/PKB-mTORC1-mediated autophagy. Blocking autophagic cell death due to excessive autophagy provides a novel strategy for the prevention of folate-resistant NTDs, especially for arsenic-exposed populations.
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Affiliation(s)
- Xiujuan Li
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Gexuan Li
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China; School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Shuo Cui
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China; School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Yue Hou
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China; School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Zelin Li
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Ziyi Yan
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China; School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Tingjuan Huang
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Taoran Zhao
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Hongkai Su
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Bingrui Zhou
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Juan Zhang
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Ruifang Ao
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Hong Zhao
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China
| | - Yulan Qiu
- School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Zhizhen Liu
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China.
| | - Jun Xie
- Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Defect and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, 030001, China.
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Zhong X, Moresco JJ, Diedrich JK, Pinto AM, SoRelle JA, Wang J, Keller K, Ludwig S, Moresco EMY, Beutler B, Choi JH. Essential role of MFSD1-GLMP-GIMAP5 in lymphocyte survival and liver homeostasis. Proc Natl Acad Sci U S A 2023; 120:e2314429120. [PMID: 38055739 PMCID: PMC10723049 DOI: 10.1073/pnas.2314429120] [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: 08/21/2023] [Accepted: 11/07/2023] [Indexed: 12/08/2023] Open
Abstract
We detected ENU-induced alleles of Mfsd1 (encoding the major facilitator superfamily domain containing 1 protein) that caused lymphopenia, splenomegaly, progressive liver pathology, and extramedullary hematopoiesis (EMH). MFSD1 is a lysosomal membrane-bound solute carrier protein with no previously described function in immunity. By proteomic analysis, we identified association between MFSD1 and both GLMP (glycosylated lysosomal membrane protein) and GIMAP5 (GTPase of immunity-associated protein 5). Germline knockout alleles of Mfsd1, Glmp, and Gimap5 each caused lymphopenia, liver pathology, EMH, and lipid deposition in the bone marrow and liver. We found that the interactions of MFSD1 and GLMP with GIMAP5 are essential to maintain normal GIMAP5 expression, which in turn is critical to support lymphocyte development and liver homeostasis that suppresses EMH. These findings identify the protein complex MFSD1-GLMP-GIMAP5 operating in hematopoietic and extrahematopoietic tissues to regulate immunity and liver homeostasis.
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Affiliation(s)
- Xue Zhong
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - James J. Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Jolene K. Diedrich
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Antonio M. Pinto
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Jeffrey A. SoRelle
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Jianhui Wang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Katie Keller
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Sara Ludwig
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Eva Marie Y. Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Jin Huk Choi
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX75390
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5
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Ma C, Li Q, Yang Y, Ge L, Cai J, Wang J, Zhu M, Xiong Y, Zhang W, Xie J, Cao Y, Zhao H, Wei Q, Huang C, Shi J, Zhang JV, Duan E, Lei X. mTOR hypoactivity leads to trophectoderm cell failure by enhancing lysosomal activation and disrupting the cytoskeleton in preimplantation embryo. Cell Biosci 2023; 13:219. [PMID: 38037142 PMCID: PMC10688112 DOI: 10.1186/s13578-023-01176-3] [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: 09/12/2023] [Accepted: 11/24/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Metabolic homeostasis is closely related to early impairment of cell fate determination and embryo development. The protein kinase mechanistic target of rapamycin (mTOR) is a key regulator of cellular metabolism in the body. Inhibition of mTOR signaling in early embryo causes postimplantation development failure, yet the mechanisms are still poorly understood. METHODS Pregnancy mice and preimplantation mouse embryo were treated with mTOR inhibitor in vivo and in vitro respectively, and subsequently examined the blastocyst formation, implantation, and post-implantation development. We used immunofluorescence staining, RNA-Seq smart2, and genome-wide bisulfite sequencing technologies to investigate the impact of mTOR inhibitors on the quality, cell fate determination, and molecular alterations in developing embryos. RESULTS We showed mTOR suppression during preimplantation decreases the rate of blastocyst formation and the competency of implantation, impairs the post implantation embryonic development. We discovered that blocking mTOR signaling negatively affected the transformation of 8-cell embryos into blastocysts and caused various deficiencies in blastocyst quality. These included problems with compromised trophectoderm cell differentiation, as well as disruptions in cell fate specification. mTOR suppression significantly affected the transcription and DNA methylation of embryos. Treatment with mTOR inhibitors increase lysosomal activation and disrupts the organization and dynamics of the actin cytoskeleton in blastocysts. CONCLUSIONS These results demonstrate that mTOR plays a crucial role in 8-cell to blastocyst transition and safeguards embryo quality during early embryo development.
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Affiliation(s)
- Chiyuan Ma
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Qin Li
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Yuxin Yang
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- School of Basic Medical Sciences and Life Sciences, Hainan Medical University, Haikou, 571199, China
| | - Lei Ge
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Jiaxuan Cai
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Juan Wang
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Maoxian Zhu
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Yue Xiong
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Wenya Zhang
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Jingtong Xie
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- School of Basic Medical Sciences and Life Sciences, Hainan Medical University, Haikou, 571199, China
| | - Yujing Cao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Huashan Zhao
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Qing Wei
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Chen Huang
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Junchao Shi
- CAS Key Laboratory of Genome Sciences and Information, China National Center for Bioinformation, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jian V Zhang
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Enkui Duan
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaohua Lei
- Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
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6
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Zhang Y, Yin YL, Jin ZY, Hu QP, Wu XG. Electroacupuncture Activates Neuroplasticity in the Motor Cortex and Corticospinal Tract via the mTOR Pathway in a Rat P-MCAO Model. BIOMED RESEARCH INTERNATIONAL 2022; 2022:3470685. [PMID: 36440366 PMCID: PMC9683956 DOI: 10.1155/2022/3470685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 11/03/2022] [Accepted: 11/05/2022] [Indexed: 10/14/2023]
Abstract
Electroacupuncture (EA) combines traditional Chinese medicine acupuncture theory with modern scientific technology. It is a promising therapy for the treatment of cerebrovascular diseases such as cerebral infarction. A large number of clinical studies have shown that EA promotes recovery of neurological function after cerebral infarction, however, the underlying mechanisms behind its effects remain unclear. We tested whether EA stimulation of the Zusanli (ST36) and Neiguan (PC6) acupoints activates neuroplasticity in rats with ischemic stroke and whether this involves the regulation of axonal regeneration through the mTOR pathway. 24 h after permanent middle cerebral artery occlusion (p-MCAO) in rats, EA treatment was started for 20 min, daily, for 14 days. We found that EA significantly reduced Modified Neurological Severity Scores (mNSS), cerebral infarct volume, and apoptosis of neuronal cells. EA also significantly increased the expression of the neuroplasticity-associated proteins GAP-43 and SYN and upregulated the phosphorylation levels of AKT, mTOR, S6, and PTEN to promote CST axon sprouting in the spinal cord at C1-C4 levels. The positive effects of EA were blocked by the administration of the mTOR inhibitor Rapamycin. In short, we found that EA of the Zusanli (ST36) and Neiguan (PC6) acupoints in p-MCAO rats induced neuroprotective and neuroplastic effects by regulating the mTOR signaling pathway. It promoted neuroplasticity activated by axon regeneration in the contralateral cortex and corticospinal tract. Activation of such endogenous remodeling is conducive to neurological recovery and may help explain the positive clinical effects seen in patients with infarcts.
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Affiliation(s)
- You Zhang
- Department of Traditional Chinese Medicine, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, 530021, China
| | - Ya-Long Yin
- Department of Traditional Chinese Medicine, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, 530021, China
| | - Zi-Yan Jin
- Department of Traditional Chinese Medicine, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, 530021, China
| | - Qi-Ping Hu
- Department of Cell Biology and Genetics, School of Pre-Clinical Medicine, Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, 530021, China
| | - Xin-gui Wu
- Department of Traditional Chinese Medicine, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, 530021, China
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7
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Francisco-Velilla R, Embarc-Buh A, Abellan S, del Caño-Ochoa F, Ramón-Maiques S, Martinez-Salas E. Phosphorylation of T897 in the dimerization domain of Gemin5 modulates protein interactions and translation regulation. Comput Struct Biotechnol J 2022; 20:6182-6191. [DOI: 10.1016/j.csbj.2022.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022] Open
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8
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Raptor downregulation rescues neuronal phenotypes in mouse models of Tuberous Sclerosis Complex. Nat Commun 2022; 13:4665. [PMID: 35945201 PMCID: PMC9363483 DOI: 10.1038/s41467-022-31961-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 07/08/2022] [Indexed: 12/16/2022] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a neurodevelopmental disorder caused by mutations in the TSC1 or TSC2 genes, which encode proteins that negatively regulate mTOR complex 1 (mTORC1) signaling. Current treatment strategies focus on mTOR inhibition with rapamycin and its derivatives. While effective at improving some aspects of TSC, chronic rapamycin inhibits both mTORC1 and mTORC2 and is associated with systemic side-effects. It is currently unknown which mTOR complex is most relevant for TSC-related brain phenotypes. Here we used genetic strategies to selectively reduce neuronal mTORC1 or mTORC2 activity in mouse models of TSC. We find that reduction of the mTORC1 component Raptor, but not the mTORC2 component Rictor, rebalanced mTOR signaling in Tsc1 knock-out neurons. Raptor reduction was sufficient to improve several TSC-related phenotypes including neuronal hypertrophy, macrocephaly, impaired myelination, network hyperactivity, and premature mortality. Raptor downregulation represents a promising potential therapeutic intervention for the neurological manifestations of TSC.
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9
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Griffey CJ, Yamamoto A. Macroautophagy in CNS health and disease. Nat Rev Neurosci 2022; 23:411-427. [PMID: 35505254 DOI: 10.1038/s41583-022-00588-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2022] [Indexed: 12/12/2022]
Abstract
Macroautophagy is an evolutionarily conserved process that delivers diverse cellular contents to lysosomes for degradation. As our understanding of this pathway grows, so does our appreciation for its importance in disorders of the CNS. Once implicated primarily in neurodegenerative events owing to acute injury and ageing, macroautophagy is now also linked to disorders of neurodevelopment, indicating that it is essential for both the formation and maintenance of a healthy CNS. In parallel to understanding the significance of macroautophagy across contexts, we have gained a greater mechanistic insight into its physiological regulation and the breadth of cargoes it can degrade. Macroautophagy is a broadly used homeostatic process, giving rise to questions surrounding how defects in this single pathway could cause diseases with distinct clinical and pathological signatures. To address this complexity, we herein review macroautophagy in the mammalian CNS by examining three key features of the process and its relationship to disease: how it functions at a basal level in the discrete cell types of the brain and spinal cord; which cargoes are being degraded in physiological and pathological settings; and how the different stages of the macroautophagy pathway intersect with diseases of neurodevelopment and adult-onset neurodegeneration.
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Affiliation(s)
- Christopher J Griffey
- Doctoral Program in Neurobiology and Behaviour, Medical Scientist Training Program, Columbia University, New York, NY, USA
| | - Ai Yamamoto
- Departments of Neurology, and Pathology and Cell Biology, Columbia University, New York, NY, USA.
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10
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Surya A, Sarinay-Cenik E. Cell autonomous and non-autonomous consequences of deviations in translation machinery on organism growth and the connecting signalling pathways. Open Biol 2022; 12:210308. [PMID: 35472285 PMCID: PMC9042575 DOI: 10.1098/rsob.210308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 03/31/2022] [Indexed: 01/09/2023] Open
Abstract
Translation machinery is responsible for the production of cellular proteins; thus, cells devote the majority of their resources to ribosome biogenesis and protein synthesis. Single-copy loss of function in the translation machinery components results in rare ribosomopathy disorders, such as Diamond-Blackfan anaemia in humans and similar developmental defects in various model organisms. Somatic copy number alterations of translation machinery components are also observed in specific tumours. The organism-wide response to haploinsufficient loss-of-function mutations in ribosomal proteins or translation machinery components is complex: variations in translation machinery lead to reduced ribosome biogenesis, protein translation and altered protein homeostasis and cellular signalling pathways. Cells are affected both autonomously and non-autonomously by changes in translation machinery or ribosome biogenesis through cell-cell interactions and secreted hormones. We first briefly introduce the model organisms where mutants or knockdowns of protein synthesis and ribosome biogenesis are characterized. Next, we specifically describe observations in Caenorhabditis elegans and Drosophila melanogaster, where insufficient protein synthesis in a subset of cells triggers cell non-autonomous growth or apoptosis responses that affect nearby cells and tissues. We then cover the characterized signalling pathways that interact with ribosome biogenesis/protein synthesis machinery with an emphasis on their respective functions during organism development.
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Affiliation(s)
- Agustian Surya
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Elif Sarinay-Cenik
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
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11
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Salamon I, Rasin MR. Evolution of the Neocortex Through RNA-Binding Proteins and Post-transcriptional Regulation. Front Neurosci 2022; 15:803107. [PMID: 35082597 PMCID: PMC8784817 DOI: 10.3389/fnins.2021.803107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/16/2021] [Indexed: 12/24/2022] Open
Abstract
The human neocortex is undoubtedly considered a supreme accomplishment in mammalian evolution. It features a prenatally established six-layered structure which remains plastic to the myriad of changes throughout an organism’s lifetime. A fundamental feature of neocortical evolution and development is the abundance and diversity of the progenitor cell population and their neuronal and glial progeny. These evolutionary upgrades are partially enabled due to the progenitors’ higher proliferative capacity, compartmentalization of proliferative regions, and specification of neuronal temporal identities. The driving force of these processes may be explained by temporal molecular patterning, by which progenitors have intrinsic capacity to change their competence as neocortical neurogenesis proceeds. Thus, neurogenesis can be conceptualized along two timescales of progenitors’ capacity to (1) self-renew or differentiate into basal progenitors (BPs) or neurons or (2) specify their fate into distinct neuronal and glial subtypes which participate in the formation of six-layers. Neocortical development then proceeds through sequential phases of proliferation, differentiation, neuronal migration, and maturation. Temporal molecular patterning, therefore, relies on the precise regulation of spatiotemporal gene expression. An extensive transcriptional regulatory network is accompanied by post-transcriptional regulation that is frequently mediated by the regulatory interplay between RNA-binding proteins (RBPs). RBPs exhibit important roles in every step of mRNA life cycle in any system, from splicing, polyadenylation, editing, transport, stability, localization, to translation (protein synthesis). Here, we underscore the importance of RBP functions at multiple time-restricted steps of early neurogenesis, starting from the cell fate transition of transcriptionally primed cortical progenitors. A particular emphasis will be placed on RBPs with mostly conserved but also divergent evolutionary functions in neural progenitors across different species. RBPs, when considered in the context of the fascinating process of neocortical development, deserve to be main protagonists in the story of the evolution and development of the neocortex.
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12
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Head B, Traber MG. Expanding role of vitamin E in protection against metabolic dysregulation: Insights gained from model systems, especially the developing nervous system of zebrafish embryos. Free Radic Biol Med 2021; 176:80-91. [PMID: 34555455 DOI: 10.1016/j.freeradbiomed.2021.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/27/2021] [Accepted: 09/07/2021] [Indexed: 12/20/2022]
Abstract
This review discusses why the embryo requires vitamin E (VitE) and shows that its lack causes metabolic dysregulation and impacts morphological changes at very early stages in development, which occur prior to when a woman knows she is pregnant. VitE halts the chain reactions of lipid peroxidation (LPO). Metabolomic analyses indicate that thiols become depleted in E- embryos because LPO generates products that require compensation using limited amino acids and methyl donors that are also developmentally relevant. Thus, VitE protects metabolic networks and the integrated gene expression networks that control development. VitE is critical especially for neurodevelopment, which is dependent on trafficking by the α-tocopherol transfer protein (TTPa). VitE-deficient (E-) zebrafish embryos initially appear normal, but by 12 and 24 h post-fertilization (hpf) E- embryos are developmentally abnormal with expression of pax2a and sox10 mis-localized in the midbrain-hindbrain boundary, neural crest cells and throughout the spinal neurons. These patterning defects indicate cells that are especially in need of VitE-protection. They precede obvious morphological abnormalities (cranial-facial malformation, pericardial edema, yolksac edema, skewed body-axis) and impaired behavioral responses to locomotor activity tests. The TTPA gene (ttpa) is expressed at the leading edges of the brain ventricle border. Ttpa knockdown using morpholinos is 100% lethal by 24 hpf, while E- embryo brains are often over- or under-inflated at 24 hpf. Further, E- embryos prior to 24 hpf have increased expression of genes involved in glycolysis and the pentose phosphate pathway, and decreased expression of genes involved in anabolic pathways and transcription. Combined data from both gene expression and the metabolome in E- embryos at 24 hpf suggest that the activity of the mechanistic Target of Rapamycin (mTOR) signaling pathway is decreased, which may impact both metabolism and neurodevelopment. Further evaluation of VitE deficiency in neurogenesis and its subsequent impact on learning and behavior is needed.
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Affiliation(s)
- Brian Head
- Linus Pauling Institute, Corvallis, OR, USA; Molecular and Cell Biology Program, Corvallis, OR, USA
| | - Maret G Traber
- Linus Pauling Institute, Corvallis, OR, USA; School of Biological and Population Health Sciences, College of Public Health and Human Sciences, Oregon State University, Corvallis, OR, USA.
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13
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Alhasan BA, Gordeev SA, Knyazeva AR, Aleksandrova KV, Margulis BA, Guzhova IV, Suvorova II. The mTOR Pathway in Pluripotent Stem Cells: Lessons for Understanding Cancer Cell Dormancy. MEMBRANES 2021; 11:858. [PMID: 34832087 PMCID: PMC8620939 DOI: 10.3390/membranes11110858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 11/16/2022]
Abstract
Currently, the success of targeted anticancer therapies largely depends on the correct understanding of the dormant state of cancer cells, since it is increasingly regarded to fuel tumor recurrence. The concept of cancer cell dormancy is often considered as an adaptive response of cancer cells to stress, and, therefore, is limited. It is possible that the cancer dormant state is not a privilege of cancer cells but the same reproductive survival strategy as diapause used by embryonic stem cells (ESCs). Recent advances reveal that high autophagy and mTOR pathway reduction are key mechanisms contributing to dormancy and diapause. ESCs, sharing their main features with cancer stem cells, have a delicate balance between the mTOR pathway and autophagy activity permissive for diapause induction. In this review, we discuss the functioning of the mTOR signaling and autophagy in ESCs in detail that allows us to deepen our understanding of the biology of cancer cell dormancy.
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Affiliation(s)
| | | | | | | | | | | | - Irina I. Suvorova
- Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia; (B.A.A.); (S.A.G.); (A.R.K.); (K.V.A.); (B.A.M.); (I.V.G.)
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14
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Lu V, Roy IJ, Teitell MA. Nutrients in the fate of pluripotent stem cells. Cell Metab 2021; 33:2108-2121. [PMID: 34644538 PMCID: PMC8568661 DOI: 10.1016/j.cmet.2021.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/07/2021] [Accepted: 09/23/2021] [Indexed: 12/11/2022]
Abstract
Pluripotent stem cells model certain features of early mammalian development ex vivo. Medium-supplied nutrients can influence self-renewal, lineage specification, and earliest differentiation of pluripotent stem cells. However, which specific nutrients support these distinct outcomes, and their mechanisms of action, remain under active investigation. Here, we evaluate the available data on nutrients and their metabolic conversion that influence pluripotent stem cell fates. We also discuss key questions open for investigation in this rapidly expanding area of increasing fundamental and practical importance.
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Affiliation(s)
- Vivian Lu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Irena J Roy
- Developmental and Stem Cell Biology, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Michael A Teitell
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA; Jonsson Comprehensive Cancer Center, California NanoSystems Institute, and Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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15
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Saba JA, Liakath-Ali K, Green R, Watt FM. Translational control of stem cell function. Nat Rev Mol Cell Biol 2021; 22:671-690. [PMID: 34272502 DOI: 10.1038/s41580-021-00386-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2021] [Indexed: 12/22/2022]
Abstract
Stem cells are characterized by their ability to self-renew and differentiate into many different cell types. Research has focused primarily on how these processes are regulated at a transcriptional level. However, recent studies have indicated that stem cell behaviour is strongly coupled to the regulation of protein synthesis by the ribosome. In this Review, we discuss how different translation mechanisms control the function of adult and embryonic stem cells. Stem cells are characterized by low global translation rates despite high levels of ribosome biogenesis. The maintenance of pluripotency, the commitment to a specific cell fate and the switch to cell differentiation depend on the tight regulation of protein synthesis and ribosome biogenesis. Translation regulatory mechanisms that impact on stem cell function include mTOR signalling, ribosome levels, and mRNA and tRNA features and amounts. Understanding these mechanisms important for stem cell self-renewal and differentiation may also guide our understanding of cancer grade and metastasis.
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Affiliation(s)
- James A Saba
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kifayathullah Liakath-Ali
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Fiona M Watt
- King's College London Centre for Stem Cells and Regenerative Medicine, Guy's Hospital, London, UK.
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16
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Mediator subunit MED1 is required for E2A-PBX1-mediated oncogenic transcription and leukemic cell growth. Proc Natl Acad Sci U S A 2021; 118:1922864118. [PMID: 33542097 DOI: 10.1073/pnas.1922864118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The chimeric transcription factor E2A-PBX1, containing the N-terminal activation domains of E2A fused to the C-terminal DNA-binding domain of PBX1, results in 5% of pediatric acute lymphoblastic leukemias (ALL). We recently have reported a mechanism for RUNX1-dependent recruitment of E2A-PBX1 to chromatin in pre-B leukemic cells; but the subsequent E2A-PBX1 functions through various coactivators and the general transcriptional machinery remain unclear. The Mediator complex plays a critical role in cell-specific gene activation by serving as a key coactivator for gene-specific transcription factors that facilitates their function through the RNA polymerase II transcriptional machinery, but whether Mediator contributes to aberrant expression of E2A-PBX1 target genes remains largely unexplored. Here we show that Mediator interacts directly with E2A-PBX1 through an interaction of the MED1 subunit with an E2A activation domain. Results of MED1 depletion by CRISPR/Cas9 further indicate that MED1 is specifically required for E2A-PBX1-dependent gene activation and leukemic cell growth. Integrated transcriptome and cistrome analyses identify pre-B cell receptor and cell cycle regulatory genes as direct cotargets of MED1 and E2A-PBX1. Notably, complementary biochemical analyses also demonstrate that recruitment of E2A-PBX1 to a target DNA template involves a direct interaction with DNA-bound RUNX1 that can be further stabilized by EBF1. These findings suggest that E2A-PBX1 interactions with RUNX1 and MED1/Mediator are of functional importance for both gene-specific transcriptional activation and maintenance of E2A-PBX1-driven leukemia. The MED1 dependency for E2A-PBX1-mediated gene activation and leukemogenesis may provide a potential therapeutic opportunity by targeting MED1 in E2A-PBX1+ pre-B leukemia.
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17
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Makwana V, Rudrawar S, Anoopkumar-Dukie S. Signalling transduction of O-GlcNAcylation and PI3K/AKT/mTOR-axis in prostate cancer. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166129. [PMID: 33744394 DOI: 10.1016/j.bbadis.2021.166129] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/26/2021] [Accepted: 03/14/2021] [Indexed: 12/23/2022]
Abstract
Hexosamine biosynthetic (HBP) and PI3K/AKT/mTOR pathways are found to predominate the proliferation and survival of prostate cancer cells. Both these pathways have their own specific intermediates to propagate the secondary signals in down-stream cascades and besides having their own structured network, also have shared interconnecting branches. These interconnections are either competitive or co-operative in nature depending on the microenvironmental conditions. Specifically, in prostate cancer HBP and mTOR pathways increases the expression and protein level of androgen receptor in order to support cancer cell proliferation, advancement and metastasis. Pharmacological inhibition of a single pathway is therefore insufficient to stop disease progression as the cancer cells manage to alter the signalling channel. This is one of the primary reasons for the therapeutic failure in prostate cancer and emergence of chemoresistance. Inhibition of these multiple pathways at their common junctures might prove to be of benefit in men suffering from an advanced disease state. Hence, a thorough understanding of these cellular intersecting points and their significance with respect to signal transduction mechanisms might assist in the rational designing of combinations for effective management of prostate cancer.
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Affiliation(s)
- Vivek Makwana
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast, QLD 4222, Australia
| | - Santosh Rudrawar
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast, QLD 4222, Australia; Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD 4222, Australia; Quality Use of Medicines Network, Griffith University, Gold Coast, QLD 4222, Australia.
| | - Shailendra Anoopkumar-Dukie
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast, QLD 4222, Australia; Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD 4222, Australia; Quality Use of Medicines Network, Griffith University, Gold Coast, QLD 4222, Australia.
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18
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Pacheco J, Wills RC, Hammond GRV. Induced Dimerization Tools to Deplete Specific Phosphatidylinositol Phosphates. Methods Mol Biol 2021; 2251:105-120. [PMID: 33481234 DOI: 10.1007/978-1-0716-1142-5_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Chemical dimerization systems have been used to drive acute depletion of polyphosphoinsitides (PPIns). They do so by inducing subcellular localization of enzymes that catabolize PPIns. By using this approach, all seven PPIns can be depleted in living cells and in real time. The rapid permeation of dimerizer agents and the specific expression of recruiter proteins confer great spatial and temporal resolution with minimal cell perturbation. In this chapter, we provide detailed instructions to monitor and induce depletion of PPIns in live cells.
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Affiliation(s)
- Jonathan Pacheco
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rachel C Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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19
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Sokolov AM, Feliciano DM. Slc7a5 regulation of neural development. Neural Regen Res 2021; 16:1994-1995. [PMID: 33642374 PMCID: PMC8343322 DOI: 10.4103/1673-5374.308086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Aidan M Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
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20
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Sokolov AM, Holmberg JC, Feliciano DM. The amino acid transporter Slc7a5 regulates the mTOR pathway and is required for granule cell development. Hum Mol Genet 2020; 29:3003-3013. [PMID: 32821949 PMCID: PMC7645712 DOI: 10.1093/hmg/ddaa186] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 08/15/2020] [Indexed: 12/11/2022] Open
Abstract
Pathogenic mutations in the solute carrier family 7 member 5 (SLC7A5) gene, which encodes an amino acid transporter cause microcephaly and seizures, yet the mechanisms responsible for these phenotypes are unclear. Models have demonstrated that Slc7a5 deletion is embryonic lethal and that these embryos lack a fully formed telencephalon. This phenotype is similar to that of mammalian target of rapamycin (mTOR) protein kinase deletion or mTOR inhibition. Notably, in many cells, Slc7a5 import of amino acids is required to maintain mTOR activity. Slc7a5 is present within neurogenic regions during embryogenesis, is found in cultured neurons and can modulate neuronal electrophysiological properties. However, Slc7a5 is also highly expressed within endothelial cells of the blood-brain barrier where removal in conditional mice leads to severe behavioral defects and non-cell autonomous changes in neurons. Therefore, the extent that neural Slc7a5 is required for development is unclear. Here, subventricular zone neural stem cells that generate olfactory bulb granule cell neurons were electroporated with SLC7A5 or Slc7a5 short hairpin RNA encoding plasmids. Although early phases of neural development were unaltered, Slc7a5 knockdown effected late phases of GC dendrite maturation and survival. Slc7a5 knockdown also decreased mTOR pathway activity. Ras homolog enriched in brain, an mTOR activator, rescued the effect of Slc7a5 knockdown on mTOR pathway activity and dendrite arbors. The data presented here demonstrate that Slc7a5 is required for GC mTOR pathway activity, maturation and survival, which may help explain why Slc7a5 mutations prevent normal brain development and function.
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Affiliation(s)
- Aidan M Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Jennie C Holmberg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
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21
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Soliman GA, Schooling CM. Causal association between mTOR-dependent EIF-4E and EIF-4A circulating protein levels and type 2 diabetes: a Mendelian randomization study. Sci Rep 2020; 10:15737. [PMID: 32978410 PMCID: PMC7519073 DOI: 10.1038/s41598-020-71987-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 08/19/2020] [Indexed: 12/22/2022] Open
Abstract
The mammalian Target of Rapamycin complex 1 (mTORC1) nutrient-sensing pathway is a central regulator of cell growth and metabolism and is dysregulated in diabetes. The eukaryotic translation initiation factor 4E (EIF-4E) protein, a key regulator of gene translation and protein function, is controlled by mTORC1 and EIF-4E Binding Proteins (EIF4EBPs). Both EIF4EBPs and ribosomal protein S6K kinase (RP-S6K) are downstream effectors regulated by mTORC1 but converge to regulate two independent pathways. We investigated whether the risk of type 2 diabetes varied with genetically predicted EIF-4E, EIF-4A, EIF-4G, EIF4EBP, and RP-S6K circulating levels using Mendelian Randomization. We estimated the causal role of EIF-4F complex, EIF4EBP, and S6K in the circulation on type 2 diabetes, based on independent single nucleotide polymorphisms strongly associated (p = 5 × 10–6) with EIF-4E (16 SNPs), EIF-4A (11 SNPs), EIF-4G (6 SNPs), EIF4EBP2 (12 SNPs), and RP-S6K (16 SNPs). The exposure data were obtained from the INTERVAL study. We applied these SNPs for each exposure to publically available genetic associations with diabetes from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) case (n = 26,676) and control (n = 132,532) study (mean age 57.4 years). We meta-analyzed SNP-specific Wald-estimates using inverse variance weighting with multiplicative random effects and conducted sensitivity analysis. Mendelian Randomization (MR-Base) R package was used in the analysis. The PhenoScanner curated database was used to identify disease associations with SNP gene variants. EIF-4E is associated with a lowered risk of type 2 diabetes with an odds ratio (OR) 0.94, 95% confidence interval (0.88, 0.99, p = 0.03) with similar estimates from the weighted median and MR-Egger. Similarly, EIF-4A was associated with lower risk of type 2 diabetes with odds ratio (OR) 0.90, 95% confidence interval (0.85, 0.97, p = 0.0003). Sensitivity analysis using MR-Egger and weighed median analysis does not indicate that there is a pleiotropic effect. This unbiased Mendelian Randomization estimate is consistent with a protective causal association of EIF-4E and EIF-4A on type 2 diabetes. EIF-4E and EIF-4A may be targeted for intervention by repurposing existing therapeutics to reduce the risk of type 2 diabetes.
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Affiliation(s)
- Ghada A Soliman
- Department of Environmental, Occupational and Geospatial Health Sciences, The City University of New York, Graduate School of Public Health and Health Policy, 55 West 125th St, New York, NY, 10027, USA.
| | - C Mary Schooling
- Department of Environmental, Occupational and Geospatial Health Sciences, The City University of New York, Graduate School of Public Health and Health Policy, 55 West 125th St, New York, NY, 10027, USA.,School of Public Health, Li Ka Shing, Faculty of Medicine, The University of Hong Kong, 7 Sassoon Road, Hong Kong, China
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22
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Li D, Ni XF, Tang H, Zhang J, Zheng C, Lin J, Wang C, Sun L, Chen B. KRT17 Functions as a Tumor Promoter and Regulates Proliferation, Migration and Invasion in Pancreatic Cancer via mTOR/S6k1 Pathway. Cancer Manag Res 2020; 12:2087-2095. [PMID: 32256116 PMCID: PMC7090205 DOI: 10.2147/cmar.s243129] [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: 12/20/2019] [Accepted: 02/14/2020] [Indexed: 12/19/2022] Open
Abstract
Background Pancreatic cancer (PC) is one of the most well-known malignancies with high mortality, but the underlying mechanism of PC remains unknown. Keratin17 (KRT17) expression has been reported in many malignancies, but its functions in PC are not clear. The aim of our study was to evaluate KRT17 expression and its potential role in PC. Methods The online databases GEPIA and THPA were used to identify KRT17 expression in tissues. Quantitative real-time PCR (qRT-PCR) was used to determine KRT17 expression in cell lines. Ki67 and ROS levels were detected by immunofluorescence assay and a 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFH-DA) probe. KRT17 downregulation was induced by the small interfering RNA (siRNA) technique. Proliferation function was evaluated by colony formation assay and RTCA. Migration and invasion were evaluated by transwell migration assay. A Western blot assay was used to detect protein levels. Results KRT17 was overexpressed in PC tissues compared to that in normal tissues. The results showed that Ki67 and ROS levels were decreased in pancreatic cancer cells after transfection with siKRT17. After KRT17 downregulation in PC cell lines, cell viability functions, including proliferation, migration and invasion, and mTOR/S6K1 phosphorylation levels were attenuated. Conclusion KRT17 knockdown significantly inhibited proliferation, migration and invasion in pancreatic cancer cells.
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Affiliation(s)
- Ding Li
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Xiao-Feng Ni
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Hengjie Tang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jiecheng Zhang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Chenlei Zheng
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jianhu Lin
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Cheng Wang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Linxiao Sun
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Bicheng Chen
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China.,Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
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23
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Poncet N, Halley PA, Lipina C, Gierliński M, Dady A, Singer GA, Febrer M, Shi Y, Yamaguchi TP, Taylor PM, Storey KG. Wnt regulates amino acid transporter Slc7a5 and so constrains the integrated stress response in mouse embryos. EMBO Rep 2020; 21:e48469. [PMID: 31789450 PMCID: PMC6944906 DOI: 10.15252/embr.201948469] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/18/2019] [Accepted: 10/25/2019] [Indexed: 12/29/2022] Open
Abstract
Amino acids are essential for cellular metabolism, and it is important to understand how nutrient supply is coordinated with changing energy requirements during embryogenesis. Here, we show that the amino acid transporter Slc7a5/Lat1 is highly expressed in tissues undergoing morphogenesis and that Slc7a5-null mouse embryos have profound neural and limb bud outgrowth defects. Slc7a5-null neural tissue exhibited aberrant mTORC1 activity and cell proliferation; transcriptomics, protein phosphorylation and apoptosis analyses further indicated induction of the integrated stress response as a potential cause of observed defects. The pattern of stress response gene expression induced in Slc7a5-null embryos was also detected at low level in wild-type embryos and identified stress vulnerability specifically in tissues undergoing morphogenesis. The Slc7a5-null phenotype is reminiscent of Wnt pathway mutants, and we show that Wnt/β-catenin loss inhibits Slc7a5 expression and induces this stress response. Wnt signalling therefore normally supports the metabolic demands of morphogenesis and constrains cellular stress. Moreover, operation in the embryo of the integrated stress response, which is triggered by pathogen-mediated as well as metabolic stress, may provide a mechanistic explanation for a range of developmental defects.
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Affiliation(s)
- Nadège Poncet
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
- Present address:
Institute of PhysiologyUniversity of ZürichZürichSwitzerland
| | - Pamela A Halley
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Christopher Lipina
- Division of Cell Signalling and ImmunologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Marek Gierliński
- Division of Computational BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Alwyn Dady
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Gail A Singer
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Melanie Febrer
- Sequencing FacilitySchool of Life SciencesUniversity of DundeeDundeeUK
- Present address:
Illumina CanadaVictoriaBCCanada
| | - Yun‐Bo Shi
- Section on Molecular MorphogenesisNICHD, NIHBethesdaMDUSA
| | - Terry P Yamaguchi
- Cancer and Developmental Biology LaboratoryCenter for Cancer ResearchNational Cancer Institute‐Frederick, NIHFrederickMDUSA
| | - Peter M Taylor
- Division of Cell Signalling and ImmunologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Kate G Storey
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
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Kim J, Guan KL. mTOR as a central hub of nutrient signalling and cell growth. Nat Cell Biol 2019; 21:63-71. [PMID: 30602761 DOI: 10.1038/s41556-018-0205-1] [Citation(s) in RCA: 623] [Impact Index Per Article: 124.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/23/2018] [Indexed: 12/19/2022]
Abstract
The highly conserved protein kinase mechanistic target of rapamycin (mTOR; originally known as mammalian target of rapamycin) is a central cell growth regulator connecting cellular metabolism and growth with a wide range of environmental inputs as part of mTOR complex 1 (mTORC1) and mTORC2. In this Review, we introduce the landmark discoveries in the mTOR field, starting from the isolation of rapamycin to the molecular characterizations of key components of the mTORC signalling network with an emphasis on amino acid sensing, and discuss the perspectives of mTORC inhibitors in therapeutic applications.
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Affiliation(s)
- Joungmok Kim
- Department of Oral Biochemistry and Molecular Biology, School of Dentistry, Kyung Hee University, Seoul, Korea.
| | - Kun-Liang Guan
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA.
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25
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Hill JW, Elias CF. Neuroanatomical Framework of the Metabolic Control of Reproduction. Physiol Rev 2019; 98:2349-2380. [PMID: 30109817 DOI: 10.1152/physrev.00033.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.
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Affiliation(s)
- Jennifer W Hill
- Center for Diabetes and Endocrine Research, Departments of Physiology and Pharmacology and of Obstetrics and Gynecology, University of Toledo College of Medicine , Toledo, Ohio ; and Departments of Molecular and Integrative Physiology and of Obstetrics and Gynecology, University of Michigan , Ann Arbor, Michigan
| | - Carol F Elias
- Center for Diabetes and Endocrine Research, Departments of Physiology and Pharmacology and of Obstetrics and Gynecology, University of Toledo College of Medicine , Toledo, Ohio ; and Departments of Molecular and Integrative Physiology and of Obstetrics and Gynecology, University of Michigan , Ann Arbor, Michigan
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Abstract
Mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase of the phosphatidylinositol kinase-related kinase family that regulates cell growth, metabolism, and autophagy. Extensive research has linked mTOR to several human diseases including cancer, neurodegenerative disorders, and aging. In this review, recent publications regarding the mechanisms underlying the role of mTOR in female reproduction under physiological and pathological conditions are summarized. Moreover, we assess whether strategies to improve or suppress mTOR expression could have therapeutic potential for reproductive diseases like premature ovarian failure, polycystic ovarian syndrome, and endometriosis.
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Oliveira D, Leal GF, Sertié AL, Caires Jr LC, Goulart E, Musso CM, Oliveira JRMD, Krepischi ACV, Vianna-Morgante AM, Zatz M. 10q23.31 microduplication encompassing PTEN decreases mTOR signalling activity and is associated with autosomal dominant primary microcephaly. J Med Genet 2018; 56:543-547. [DOI: 10.1136/jmedgenet-2018-105471] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/07/2018] [Accepted: 08/29/2018] [Indexed: 01/15/2023]
Abstract
BackgroundHereditary primary microcephaly (MCPH) is mainly characterised by decreased occipitofrontal circumference and variable degree of intellectual disability. MCPH with a dominant pattern of inheritance is a rare condition, so far causally linked to pathogenic variants in the ALFY, DPP6, KIF11 and DYRK1A genes.ObjectiveThis study aimed at identifying the causative variant of the autosomal dominant form of MCPH in a Brazilian family with three affected members.MethodsFollowing clinical evaluation of two sibs and their mother presenting with autosomal dominant MCPH, array comparative genome hybridisation was performed using genomic DNA from peripheral blood of the family members. Gene and protein expression studies were carried out in cultured skin fibroblasts.ResultsA 382 kb microduplication at 10q23.31 was detected, encompassing the entire PTEN, KLLN and ATAD1 genes. PTEN haploinsufficiency has been causally associated with macrocephaly and autism spectrum disorder and, therefore, was considered the most likely candidate gene to be involved in this autosomal dominant form of MCPH. In the patients’ fibroblasts, PTEN mRNA and protein were found to be overexpressed, and the phosphorylation patterns of upstream and downstream components of the mammalian target of rapamycin (mTOR) signalling pathway were dysregulated.ConclusionsTaken together, our results demonstrate that the identified submicroscopic 10q23.31 duplication in a family with MCPH leads to markedly increased expression of PTEN and reduced activity of the mTOR signalling pathway. These results suggest that the most probable pathomechanism underlying the microcephaly phenotype in this family involves downregulation of the mTOR pathway through overexpression of PTEN.
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28
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Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:6141902. [PMID: 30305865 PMCID: PMC6165581 DOI: 10.1155/2018/6141902] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/04/2018] [Indexed: 12/21/2022]
Abstract
Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.
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29
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Abstract
The mechanistic target of rapamycin (mTOR) is an important signaling hub that integrates environmental information regarding energy availability and stimulates anabolic molecular processes and cell growth. Abnormalities in this pathway have been identified in several syndromes in which autism spectrum disorder (ASD) is highly prevalent. Several studies have investigated mTOR signaling in developmental and neuronal processes that, when dysregulated, could contribute to the development of ASD. Although many potential mechanisms still remain to be fully understood, these associations are of great interest because of the clinical availability of mTOR inhibitors. Clinical trials evaluating the efficacy of mTOR inhibitors to improve neurodevelopmental outcomes have been initiated.
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Affiliation(s)
- Kellen D. Winden
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Darius Ebrahimi-Fakhari
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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30
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Aldaregia J, Odriozola A, Matheu A, Garcia I. Targeting mTOR as a Therapeutic Approach in Medulloblastoma. Int J Mol Sci 2018; 19:ijms19071838. [PMID: 29932116 PMCID: PMC6073374 DOI: 10.3390/ijms19071838] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/12/2018] [Accepted: 06/20/2018] [Indexed: 12/11/2022] Open
Abstract
Mechanistic target of rapamycin (mTOR) is a master signaling pathway that regulates organismal growth and homeostasis, because of its implication in protein and lipid synthesis, and in the control of the cell cycle and the cellular metabolism. Moreover, it is necessary in cerebellar development and stem cell pluripotency maintenance. Its deregulation has been implicated in the medulloblastoma and in medulloblastoma stem cells (MBSCs). Medulloblastoma is the most common malignant solid tumor in childhood. The current therapies have improved the overall survival but they carry serious side effects, such as permanent neurological sequelae and disability. Recent studies have given rise to a new molecular classification of the subgroups of medulloblastoma, specifying 12 different subtypes containing novel potential therapeutic targets. In this review we propose the targeting of mTOR, in combination with current therapies, as a promising novel therapeutic approach.
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Affiliation(s)
- Juncal Aldaregia
- Cellular Oncology Group, Biodonostia Research Institute, 20014 Donostia-San Sebastián, Spain.
| | - Ainitze Odriozola
- Cellular Oncology Group, Biodonostia Research Institute, 20014 Donostia-San Sebastián, Spain.
| | - Ander Matheu
- Cellular Oncology Group, Biodonostia Research Institute, 20014 Donostia-San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain.
- CIBER de fragilidad y envejecimiento saludable (CIBERfes), 28029 Madrid, Spain.
| | - Idoia Garcia
- Cellular Oncology Group, Biodonostia Research Institute, 20014 Donostia-San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain.
- CIBER de fragilidad y envejecimiento saludable (CIBERfes), 28029 Madrid, Spain.
- Physiology Department, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain.
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31
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Lee S, Won M, Hwang RH, Hur GM, Ro H. An Ecdysone Receptor-based Singular Gene Switch for Deliberate Expression of Transgene with Robustness, Reversibility, and Negligible Leakiness. J Vis Exp 2018. [PMID: 29781995 DOI: 10.3791/57494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Precise control of transgene expression is desirable in biological and clinical studies. However, because the binary feature of currently employed gene switches requires the transfer of two therapeutic expression units concurrently into a single cell, the practical application of the system for gene therapy is limited. To simplify the transgene expression system, we generated a gene switch designated as pEUI(+) encompassing a complete set of transgene expression modules in a single vector. Comprising of the GAL4 DNA-binding domain and modified EcR (GvEcR), a minimal VP16 activation domain fused with a GAL4 DNA-binding domain, as well as a modified Drosophila ecdysone receptor (EcR), the newly developed singular gene switch is highly responsive to the administration of a chemical inducer in a time- and dosage-dependent manner. The pEUI(+) vector is a potentially powerful tool for improving the control of transgene expression in both biological research and pre-clinical studies. Here, we present a detailed protocol for modulation of a transient and stable transgene expression using pEUI(+) vector by the treatment of tebufenozide (Teb). Additionally, we share important guidelines for the use of Teb as a chemical inducer.
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Affiliation(s)
- Seoghyun Lee
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University
| | - Minho Won
- Department of Pharmacology, College of Medicine, Chungnam National University
| | | | - Gang Min Hur
- Department of Pharmacology, College of Medicine, Chungnam National University;
| | - Hyunju Ro
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University;
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Zareen N, Dodson S, Armada K, Awad R, Sultana N, Hara E, Alexander H, Martin JH. Stimulation-dependent remodeling of the corticospinal tract requires reactivation of growth-promoting developmental signaling pathways. Exp Neurol 2018; 307:133-144. [PMID: 29729248 DOI: 10.1016/j.expneurol.2018.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/18/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022]
Abstract
The corticospinal tract (CST) can become damaged after spinal cord injury or stroke, resulting in weakness or paralysis. Repair of the damaged CST is limited because mature CST axons fail to regenerate, which is partly because the intrinsic axon growth capacity is downregulated in maturity. Whereas CST axons sprout after injury, this is insufficient to recover lost functions. Chronic motor cortex (MCX) electrical stimulation is a neuromodulatory strategy to promote CST axon sprouting, leading to functional recovery after CST lesion. Here we examine the molecular mechanisms of stimulation-dependent CST axonal sprouting and synapse formation. MCX stimulation rapidly upregulates mTOR and Jak/Stat signaling in the corticospinal system. Chronic stimulation, which leads to CST sprouting and increased CST presynaptic sites, further enhances mTOR and Jak/Stat activity. Importantly, chronic stimulation shifts the equilibrium of the mTOR repressor PTEN to the inactive phosphorylated form suggesting a molecular transition to an axon growth state. We blocked each signaling pathway selectively to determine potential differential contributions to axonal outgrowth and synapse formation. mTOR blockade prevented stimulation-dependent axon sprouting. Surprisingly, Jak/Stat blockade did not abrogate sprouting, but instead prevented the increase in CST presynaptic sites produced by chronic MCX stimulation. Chronic stimulation increased the number of spinal neurons expressing the neural activity marker cFos. Jak/Stat blockade prevented the increase in cFos-expressing neurons after chronic stimulation, confirming an important role for Jak/Stat signaling in activity-dependent CST synapse formation. MCX stimulation is a neuromodulatory repair strategy that reactivates distinct developmentally-regulated signaling pathways for axonal outgrowth and synapse formation.
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Affiliation(s)
- Neela Zareen
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Shahid Dodson
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Kristine Armada
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Rahma Awad
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Nadia Sultana
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Erina Hara
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Heather Alexander
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA.
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Marsh D, Dragich JM. Autophagy in mammalian neurodevelopment and implications for childhood neurological disorders. Neurosci Lett 2018; 697:29-33. [PMID: 29665429 DOI: 10.1016/j.neulet.2018.04.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/06/2018] [Accepted: 04/08/2018] [Indexed: 01/05/2023]
Abstract
Here we explore the neurodevelopmental aspects of macroautophagy (henceforth known as autophagy), the process by which cells remove and remodel their structure in a regulated and spatially restricted manner. Autophagy is a catabolic pathway in which cytosolic substances, such as protein complexes, lipids, and organelles, are engulfed by an autophagic vesicle. Degradation occurs once an autophagosome fuses with a lysosome, allowing the macromolecular cargo sequestered within the autophagic vesicle to be recycled. It is firmly established that autophagy plays a pivotal role in maintaining cellular homeostasis. Nevertheless, new evidence has emerged that the molecular mechanisms which regulate brain growth and neuronal connectivity involve autophagic processes. Our aim, as we endeavor to review data from model systems, is to show that autophagy performs a fundamental role in the development of the central nervous system (CNS). Moreover, we discuss human genetic data to underscore that mutations in autophagy-related genes are a contributing factor in childhood neurological disorders. To emphasize the importance of regulated vesicle transport pathways during the formation of the CNS, we discuss autophagy in relation to endosomal sorting to the lysosome, and explore how these mechanisms might intersect to regulate developmental events. We maintain that a deeper understanding of the function of autophagy in the CNS can shed new light on the biological basis of neurodevelopmental disorders.
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Affiliation(s)
- Derek Marsh
- Biology Department, Manhattan College, Riverdale, NY, United States
| | - Joanna M Dragich
- Biology Department, Manhattan College, Riverdale, NY, United States; Department of Neurology, Columbia University Medical Center, New York, NY, United States.
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Dysregulation of cotranscriptional alternative splicing underlies CHARGE syndrome. Proc Natl Acad Sci U S A 2018; 115:E620-E629. [PMID: 29311329 DOI: 10.1073/pnas.1715378115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
CHARGE syndrome-which stands for coloboma of the eye, heart defects, atresia of choanae, retardation of growth/development, genital abnormalities, and ear anomalies-is a severe developmental disorder with wide phenotypic variability, caused mainly by mutations in CHD7 (chromodomain helicase DNA-binding protein 7), known to encode a chromatin remodeler. The genetic lesions responsible for CHD7 mutation-negative cases are unknown, at least in part because the pathogenic mechanisms underlying CHARGE syndrome remain poorly defined. Here, we report the characterization of a mouse model for CHD7 mutation-negative cases of CHARGE syndrome generated by insertional mutagenesis of Fam172a (family with sequence similarity 172, member A). We show that Fam172a plays a key role in the regulation of cotranscriptional alternative splicing, notably by interacting with Ago2 (Argonaute-2) and Chd7. Validation studies in a human cohort allow us to propose that dysregulation of cotranscriptional alternative splicing is a unifying pathogenic mechanism for both CHD7 mutation-positive and CHD7 mutation-negative cases. We also present evidence that such splicing defects can be corrected in vitro by acute rapamycin treatment.
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mTOR-Dependent Cell Proliferation in the Brain. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7082696. [PMID: 29259984 PMCID: PMC5702949 DOI: 10.1155/2017/7082696] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/22/2017] [Indexed: 02/08/2023]
Abstract
The mammalian Target of Rapamycin (mTOR) is a molecular complex equipped with kinase activity which controls cell viability being key in the PI3K/PTEN/Akt pathway. mTOR acts by integrating a number of environmental stimuli to regulate cell growth, proliferation, autophagy, and protein synthesis. These effects are based on the modulation of different metabolic pathways. Upregulation of mTOR associates with various pathological conditions, such as obesity, neurodegeneration, and brain tumors. This is the case of high-grade gliomas with a high propensity to proliferation and tissue invasion. Glioblastoma Multiforme (GBM) is a WHO grade IV malignant, aggressive, and lethal glioma. To date, a few treatments are available although the outcome of GBM patients remains poor. Experimental and pathological findings suggest that mTOR upregulation plays a major role in determining an aggressive phenotype, thus determining relapse and chemoresistance. Among several activities, mTOR-induced autophagy suppression is key in GBM malignancy. In this article, we discuss recent evidence about mTOR signaling and its role in normal brain development and pathological conditions, with a special emphasis on its role in GBM.
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Vieira MNN, Lima-Filho RAS, De Felice FG. Connecting Alzheimer's disease to diabetes: Underlying mechanisms and potential therapeutic targets. Neuropharmacology 2017; 136:160-171. [PMID: 29129775 DOI: 10.1016/j.neuropharm.2017.11.014] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is a risk factor for type 2 diabetes and vice versa, and a growing body of evidence indicates that these diseases are connected both at epidemiological, clinical and molecular levels. Recent studies have begun to reveal common pathogenic mechanisms shared by AD and type 2 diabetes. Impaired neuronal insulin signaling and endoplasmic reticulum (ER) stress are present in animal models of AD, similar to observations in peripheral tissue in T2D. These findings shed light into novel diabetes-related mechanisms leading to brain dysfunction in AD. Here, we review the literature on selected mechanisms shared between these diseases and discuss how the identification of such mechanisms may lead to novel therapeutic targets in AD. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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Affiliation(s)
- Marcelo N N Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
| | - Ricardo A S Lima-Filho
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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37
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Abstract
In my PNAS Inaugural Article, I describe the development of the mTOR field, starting with efforts to understand the mechanism of action of the drug rapamycin, which ∼25 y ago led to the discovery of the mTOR protein kinase. I focus on insights that we have contributed and on work that has been particularly influential to me, as well as provide some personal reflections and stories. We now appreciate that, as part of two distinct complexes, mTORC1 and mTORC2, mTOR is the major regulator of growth (mass accumulation) in animals and is the key link between the availability of nutrients in the environment and the control of most anabolic and catabolic processes. Nutrients signal to mTORC1 through the lysosome-associated Rag GTPases and their many regulators and associated cytosolic and lysosomal nutrient sensors. mTOR signaling is deregulated in common diseases, like cancer and epilepsy, and mTORC1 is a well-validated modulator of aging in multiple model organisms. There is significant excitement around using mTORC1 inhibitors to treat cancer and neurological disease and, potentially, to improve healthspan and lifespan.
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38
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Hanai S, Sukigara S, Dai H, Owa T, Horike SI, Otsuki T, Saito T, Nakagawa E, Ikegaya N, Kaido T, Sato N, Takahashi A, Sugai K, Saito Y, Sasaki M, Hoshino M, Goto YI, Koizumi S, Itoh M. Pathologic Active mTOR Mutation in Brain Malformation with Intractable Epilepsy Leads to Cell-Autonomous Migration Delay. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:1177-1185. [PMID: 28427592 DOI: 10.1016/j.ajpath.2017.01.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/19/2017] [Indexed: 01/08/2023]
Abstract
The activation of phosphatidylinositol 3-kinase-AKTs-mammalian target of rapamycin cell signaling pathway leads to cell overgrowth and abnormal migration and results in various types of cortical malformations, such as hemimegalencephaly (HME), focal cortical dysplasia, and tuberous sclerosis complex. However, the pathomechanism underlying abnormal cell migration remains unknown. With the use of fetal mouse brain, we performed causative gene analysis of the resected brain tissues from a patient with HME and investigated the pathogenesis. We obtained a novel somatic mutation of the MTOR gene, having approximately 11% and 7% mutation frequency in the resected brain tissues. Moreover, we revealed that the MTOR mutation resulted in hyperphosphorylation of its downstream molecules, S6 and 4E-binding protein 1, and delayed cell migration on the radial glial fiber and did not affect other cells. We suspect cell-autonomous migration arrest on the radial glial foot by the active MTOR mutation and offer potential explanations for why this may lead to cortical malformations such as HME.
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Affiliation(s)
- Sae Hanai
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Sayuri Sukigara
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Hongmei Dai
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Tomoo Owa
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, Kodaira, Japan
| | - Shin-Ichi Horike
- Division of Functional Genomics, Advanced Science Research Center Kanazawa University, Kanazawa, Japan
| | - Taisuke Otsuki
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Takashi Saito
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Eiji Nakagawa
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Naoki Ikegaya
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Takanobu Kaido
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Noriko Sato
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Radiology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Akio Takahashi
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Kenji Sugai
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Yuko Saito
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Laboratory Medicine, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Masayuki Sasaki
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Mikio Hoshino
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, Kodaira, Japan
| | - Yu-Ichi Goto
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
| | - Masayuki Itoh
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan.
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39
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Zou LP, Liu YT. Letter re: Sirolimus for epilepsy in children with tuberous sclerosis complex: A randomized controlled trial. Neurology 2017; 88:1008. [DOI: 10.1212/wnl.0000000000003703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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40
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Lee S, Sohn KC, Choi DK, Won M, Park KA, Ju SK, Kang K, Bae YK, Hur GM, Ro H. Ecdysone Receptor-based Singular Gene Switches for Regulated Transgene Expression in Cells and Adult Rodent Tissues. MOLECULAR THERAPY-NUCLEIC ACIDS 2016; 5:e367. [PMID: 27673563 PMCID: PMC5056996 DOI: 10.1038/mtna.2016.74] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 07/25/2016] [Indexed: 11/09/2022]
Abstract
Controlled gene expression is an indispensable technique in biomedical research. Here, we report a convenient, straightforward, and reliable way to induce expression of a gene of interest with negligible background expression compared to the most widely used tetracycline (Tet)-regulated system. Exploiting a Drosophila ecdysone receptor (EcR)-based gene regulatory system, we generated nonviral and adenoviral singular vectors designated as pEUI(+) and pENTR-EUI, respectively, which contain all the required elements to guarantee regulated transgene expression (GAL4-miniVP16-EcR, termed GvEcR hereafter, and 10 tandem repeats of an upstream activation sequence promoter followed by a multiple cloning site). Through the transient and stable transfection of mammalian cell lines with reporter genes, we validated that tebufenozide, an ecdysone agonist, reversibly induced gene expression, in a dose- and time-dependent manner, with negligible background expression. In addition, we created an adenovirus derived from the pENTR-EUI vector that readily infected not only cultured cells but also rodent tissues and was sensitive to tebufenozide treatment for regulated transgene expression. These results suggest that EcR-based singular gene regulatory switches would be convenient tools for the induction of gene expression in cells and tissues in a tightly controlled fashion.
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Affiliation(s)
- Seoghyun Lee
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Kyung-Cheol Sohn
- Department of Dermatology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Dae-Kyoung Choi
- Department of Dermatology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Minho Won
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Kyeong Ah Park
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Sung-Kyu Ju
- Affiliated Research (and Development) Institute, Daejeon, Republic of Korea
| | - Kidong Kang
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Young-Ki Bae
- Comparative Biomedical Research Branch, Research Institute, National Cancer Center, Goyang, Republic of Korea
| | - Gang Min Hur
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Hyunju Ro
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
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41
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Chronic rapamycin treatment on the nutrient utilization and metabolism of juvenile turbot (Psetta maxima). Sci Rep 2016; 6:28068. [PMID: 27305975 PMCID: PMC4910097 DOI: 10.1038/srep28068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/31/2016] [Indexed: 12/04/2022] Open
Abstract
High dietary protein inclusion is necessary in fish feeds and also represents a major cost in the aquaculture industry, which demands improved dietary conversion into body proteins in fish. In mammals, the target of rapamycin (TOR) is a key nutritionally responsive molecule governing postprandial anabolism. However, its physiological significance in teleosts has not been fully examined. In the present study, we examined the nutritional physiology of turbot after chronic rapamycin inhibition. Our results showed that a 6-week inhibition of TOR using dietary rapamycin inclusion (30 mg/kg diet) reduced growth performance and feed utilization. The rapamycin treatment inhibited TOR signaling and reduced expression of key enzymes in glycolysis, lipogenesis, cholesterol biosynthesis, while increasing the expression of enzymes involved in gluconeogenesis. Furthermore, rapamycin treatment increased intestinal goblet cell number in turbot, while the expressions of Notch and Hes1 were down regulated. It was possible that stimulated goblet cell differentiation by rapamycin was mediated through Notch-Hes1 pathway. Therefore, our results demonstrate the important role of TOR signaling in fish nutritional physiology.
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42
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SLC7 family transporters control the establishment of left-right asymmetry during organogenesis in medaka by activating mTOR signaling. Biochem Biophys Res Commun 2016; 474:146-153. [PMID: 27105919 DOI: 10.1016/j.bbrc.2016.04.087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 04/18/2016] [Indexed: 12/20/2022]
Abstract
The precise government of the left-right (LR) specification of an organ is an essential aspect of its morphogenesis. Multiple signaling cascades have been implicated in the establishment of vertebrate LR asymmetry. Recently, mTOR signaling was found to critically regulate the development of LR asymmetry in zebrafish. However, the upstream factor(s) that activate mTOR signaling in the context of LR specification are as yet unknown. In this study, we identify the SLC7 amino acid transporters Slc7a7 and Slc7a8 as novel regulators of LR asymmetry development in the small fish medaka. Knockdown of Slc7a7 and/or Slc7a8 in medaka embryos disrupted LR organ asymmetries. Depletion of Slc7a7 hindered left-sided expression of the southpaw (spaw) gene, which is responsible for LR axis determination. Work at the cellular level revealed that Slc7a7 coordinates ciliogenesis in the epithelium of Kupffer's vesicle and thereby the generation of the nodal fluid flow required for LR asymmetry. Interestingly, knockdown of Slc7a7 depressed mTOR signaling activity in medaka embryos. Treatment with rapamycin, an inhibitor of mTOR signaling, together with Slc7a7 knockdown synergistically perturbed spaw expression, indicating an interaction between Slc7a7 and mTOR signaling affecting gene expression required for LR specification. Taken together, our results demonstrate that Slc7a7 governs the regulation of LR asymmetry development via the activation of mTOR signaling.
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43
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Sucularli C, Shehwana H, Kuscu C, Dungul DC, Ozdag H, Konu O. Functionally conserved effects of rapamycin exposure on zebrafish. Mol Med Rep 2016; 13:4421-30. [PMID: 27035657 DOI: 10.3892/mmr.2016.5059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/22/2016] [Indexed: 11/06/2022] Open
Abstract
Mechanistic target of rapamycin (mTOR) is a conserved serine/threonine kinase important in cell proliferation, growth and protein translation. Rapamycin, a well‑known anti‑cancer agent and immunosuppressant drug, inhibits mTOR activity in different taxa including zebrafish. In the present study, the effect of rapamycin exposure on the transcriptome of a zebrafish fibroblast cell line, ZF4, was investigated. Microarray analysis demonstrated that rapamycin treatment modulated a large set of genes with varying functions including protein synthesis, assembly of mitochondrial and proteasomal machinery, cell cycle, metabolism and oxidative phosphorylation in ZF4 cells. A mild however, coordinated reduction in the expression of proteasomal and mitochondrial ribosomal subunits was detected, while the expression of numerous ribosomal subunits increased. Meta‑analysis of heterogeneous mouse rapamycin microarray datasets enabled the comparison of zebrafish and mouse pathways modulated by rapamycin, using Kyoto Encyclopedia of Genes and Genomes and Gene Ontology pathway analysis. The analyses demonstrated a high degree of functional conservation between zebrafish and mice in response to rapamycin. In addition, rapamycin treatment resulted in a marked dose‑dependent reduction in body size and pigmentation in zebrafish embryos. The present study is the first, to the best of our knowledge, to evaluate the conservation of rapamycin‑modulated functional pathways between zebrafish and mice, in addition to the dose‑dependent growth curves of zebrafish embryos upon rapamycin exposure.
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Affiliation(s)
- Ceren Sucularli
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara 06800, Turkey
| | - Huma Shehwana
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara 06800, Turkey
| | - Cem Kuscu
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara 06800, Turkey
| | | | - Hilal Ozdag
- Biotechnology Institute, Ankara University, Ankara 06010, Turkey
| | - Ozlen Konu
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara 06800, Turkey
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44
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Cao L, Liu P, Gill K, Reece EA, Cheema AK, Zhao Z. Identification of novel cell survival regulation in diabetic embryopathy via phospholipidomic profiling. Biochem Biophys Res Commun 2016; 470:599-605. [PMID: 26797275 PMCID: PMC4756589 DOI: 10.1016/j.bbrc.2016.01.098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 01/15/2016] [Indexed: 01/01/2023]
Abstract
Diabetes mellitus in early pregnancy causes birth defects by disturbing metabolic homeostasis and increasing programmed cell death in the embryo. Over-activation of phospholipase Cβ3 and γ1 suggests disturbed phospholipid metabolism, which is an important in regulation of cell signaling and activity. Metabolomic examinations reveal significant changes in the profile of phospholipid metabolism. Among the metabolites, levels of phosphatidylinositol bisphosphate (PIP2) are increased. PIP2 effector PTEN (phosphatase and tensin homolog deleted on chromosome 10) is activated. Activation of protein kinase Bα (PKBα, or AKT1) and mTOR (mechanistic target of rapamycin) is decreased. Inhibition of PLCs and PTEN suppresses over-generation of reactive oxygen species and inhibition of PLCs prevents fragmentation of mitochondria in neural stem cells cultured in high glucose. These observations suggest that maternal hyperglycemia disrupts phospholipid metabolism, leading to perturbation of mitochondrial dynamics and redox homeostasis and suppression of the PKB-mTOR cell survival signaling in the embryos.
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Affiliation(s)
- Lixue Cao
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Peiyan Liu
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kirandeep Gill
- Department of Oncology, Georgetown University Medical Center, Washington, DC, USA
| | - E A Reece
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Amrita K Cheema
- Department of Oncology, Georgetown University Medical Center, Washington, DC, USA; Department of Biochemistry, Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC, USA
| | - Zhiyong Zhao
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.
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45
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Tee AR, Sampson JR, Pal DK, Bateman JM. The role of mTOR signalling in neurogenesis, insights from tuberous sclerosis complex. Semin Cell Dev Biol 2016; 52:12-20. [PMID: 26849906 DOI: 10.1016/j.semcdb.2016.01.040] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/05/2016] [Accepted: 01/25/2016] [Indexed: 11/30/2022]
Abstract
Understanding the development and function of the nervous system is one of the foremost aims of current biomedical research. The nervous system is generated during a relatively short period of intense neurogenesis that is orchestrated by a number of key molecular signalling pathways. Even subtle defects in the activity of these molecules can have serious repercussions resulting in neurological, neurodevelopmental and neurocognitive problems including epilepsy, intellectual disability and autism. Tuberous sclerosis complex (TSC) is a monogenic disease characterised by these problems and by the formation of benign tumours in multiple organs, including the brain. TSC is caused by mutations in the TSC1 or TSC2 gene leading to activation of the mechanistic target of rapamycin (mTOR) signalling pathway. A desire to understand the neurological manifestations of TSC has stimulated research into the role of the mTOR pathway in neurogenesis. In this review we describe TSC neurobiology and how the use of animal model systems has provided insights into the roles of mTOR signalling in neuronal differentiation and migration. Recent progress in this field has identified novel mTOR pathway components regulating neuronal differentiation. The roles of mTOR signalling and aberrant neurogenesis in epilepsy are also discussed. Continuing efforts to understand mTOR neurobiology will help to identify new therapeutic targets for TSC and other neurological diseases.
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Affiliation(s)
- Andrew R Tee
- Institute of Cancer & Genetics, Cardiff University School of Medicine, Institute of Medical Genetics Building, Heath Park, Cardiff CF14 4XN UK
| | - Julian R Sampson
- Institute of Cancer & Genetics, Cardiff University School of Medicine, Institute of Medical Genetics Building, Heath Park, Cardiff CF14 4XN UK
| | - Deb K Pal
- Department of Basic & Clinical Neurosciences, Institute of Psychiatry, Psychology & Neuroscience, King's College, London SE5 8RX UK
| | - Joseph M Bateman
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL UK.
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46
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Carroll B, Maetzel D, Maddocks ODK, Otten G, Ratcliff M, Smith GR, Dunlop EA, Passos JF, Davies OR, Jaenisch R, Tee AR, Sarkar S, Korolchuk VI. Control of TSC2-Rheb signaling axis by arginine regulates mTORC1 activity. eLife 2016; 5:e11058. [PMID: 26742086 PMCID: PMC4764560 DOI: 10.7554/elife.11058] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/30/2015] [Indexed: 01/07/2023] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) is the key signaling hub that regulates cellular protein homeostasis, growth, and proliferation in health and disease. As a prerequisite for activation of mTORC1 by hormones and mitogens, there first has to be an available pool of intracellular amino acids. Arginine, an amino acid essential during mammalian embryogenesis and early development is one of the key activators of mTORC1. Herein, we demonstrate that arginine acts independently of its metabolism to allow maximal activation of mTORC1 by growth factors via a mechanism that does not involve regulation of mTORC1 localization to lysosomes. Instead, arginine specifically suppresses lysosomal localization of the TSC complex and interaction with its target small GTPase protein, Rheb. By interfering with TSC-Rheb complex, arginine relieves allosteric inhibition of Rheb by TSC. Arginine cooperates with growth factor signaling which further promotes dissociation of TSC2 from lysosomes and activation of mTORC1. Arginine is the main amino acid sensed by the mTORC1 pathway in several cell types including human embryonic stem cells (hESCs). Dependence on arginine is maintained once hESCs are differentiated to fibroblasts, neurons, and hepatocytes, highlighting the fundamental importance of arginine-sensing to mTORC1 signaling. Together, our data provide evidence that different growth promoting cues cooperate to a greater extent than previously recognized to achieve tight spatial and temporal regulation of mTORC1 signaling.
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Affiliation(s)
- Bernadette Carroll
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Dorothea Maetzel
- Whitehead Institute for Biomedical ResearchMassachusetts Institute of TechnologyCambridgeUnited States
| | | | - Gisela Otten
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Matthew Ratcliff
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Graham R Smith
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Elaine A Dunlop
- Institute of Cancer and GeneticsCardiff UniversityCardiffUnited Kingdom
| | - João F Passos
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Owen R Davies
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical ResearchMassachusetts Institute of TechnologyCambridgeUnited States
| | - Andrew R Tee
- Institute of Cancer and GeneticsCardiff UniversityCardiffUnited Kingdom
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Viktor I Korolchuk
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
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47
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Casar Tena T, Burkhalter MD, Philipp M. Left-right asymmetry in the light of TOR: An update on what we know so far. Biol Cell 2015; 107:306-18. [PMID: 25943139 PMCID: PMC4744706 DOI: 10.1111/boc.201400094] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/29/2015] [Indexed: 01/06/2023]
Abstract
The internal left‐right (LR) asymmetry is a characteristic that exists throughout the animal kingdom from roundworms over flies and fish to mammals. Cilia, which are antenna‐like structures protruding into the extracellular space, are involved in establishing LR asymmetry during early development. Humans who suffer from dysfunctional cilia often develop conditions such as heterotaxy, where internal organs appear to be placed randomly. As a consequence to this failure in asymmetry development, serious complications such as congenital heart defects (CHD) occur. The mammalian (or mechanistic) target of rapamycin (mTOR) pathway has recently emerged as an important regulator regarding symmetry breaking. The mTOR pathway governs fundamental processes such as protein translation or metabolism. Its activity can be transduced by two complexes, which are called TORC1 and TORC2, respectively. So far, only TORC1 has been implicated with asymmetry development and appears to require very precise regulation. A number of recent papers provided evidence that dysregulated TORC1 results in alterations of motile cilia and asymmetry defects. In here, we give an update on what we know so far of mTORC1 in LR asymmetry development.
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Affiliation(s)
- Teresa Casar Tena
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, 89081, Germany
| | - Martin D Burkhalter
- Leibniz Institute for Age Research Fritz Lippmann Institute, Jena, 07745, Germany
| | - Melanie Philipp
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, 89081, Germany
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48
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Alpha-Linolenic Acid-Induced Increase in Neurogenesis is a Key Factor in the Improvement in the Passive Avoidance Task After Soman Exposure. Neuromolecular Med 2015; 17:251-69. [DOI: 10.1007/s12017-015-8353-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/11/2015] [Indexed: 02/01/2023]
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49
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The role of TORC1 in muscle development in Drosophila. Sci Rep 2015; 5:9676. [PMID: 25866192 PMCID: PMC4394354 DOI: 10.1038/srep09676] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/16/2015] [Indexed: 01/15/2023] Open
Abstract
Myogenesis is an important process during both development and muscle repair. Previous studies suggest that mTORC1 plays a role in the formation of mature muscle from immature muscle precursor cells. Here we show that gene expression for several myogenic transcription factors including Myf5, Myog and Mef2c but not MyoD and myosin heavy chain isoforms decrease when C2C12 cells are treated with rapamycin, supporting a role for mTORC1 pathway during muscle development. To investigate the possibility that mTORC1 can regulate muscle in vivo we ablated the essential dTORC1 subunit Raptor in Drosophila melanogaster and found that muscle-specific knockdown of Raptor causes flies to be too weak to emerge from their pupal cases during eclosion. Using a series of GAL4 drivers we also show that muscle-specific Raptor knockdown also causes shortened lifespan, even when eclosure is unaffected. Together these results highlight an important role for TORC1 in muscle development, integrity and function in both Drosophila and mammalian cells.
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50
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Heras-Sandoval D, Pérez-Rojas JM, Hernández-Damián J, Pedraza-Chaverri J. The role of PI3K/AKT/mTOR pathway in the modulation of autophagy and the clearance of protein aggregates in neurodegeneration. Cell Signal 2014; 26:2694-701. [DOI: 10.1016/j.cellsig.2014.08.019] [Citation(s) in RCA: 646] [Impact Index Per Article: 64.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 08/18/2014] [Indexed: 12/13/2022]
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