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Kanaoka Y, Onodera K, Watanabe K, Hayashi Y, Usui T, Uemura T, Hattori Y. Inter-organ Wingless/Ror/Akt signaling regulates nutrient-dependent hyperarborization of somatosensory neurons. eLife 2023; 12:79461. [PMID: 36647607 PMCID: PMC9844989 DOI: 10.7554/elife.79461] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 12/11/2022] [Indexed: 01/18/2023] Open
Abstract
Nutrition in early life has profound effects on an organism, altering processes such as organogenesis. However, little is known about how specific nutrients affect neuronal development. Dendrites of class IV dendritic arborization neurons in Drosophila larvae become more complex when the larvae are reared on a low-yeast diet compared to a high-yeast diet. Our systematic search for key nutrients revealed that the neurons increase their dendritic terminal densities in response to a combined deficiency in vitamins, metal ions, and cholesterol. The deficiency of these nutrients upregulates Wingless in a closely located tissue, body wall muscle. Muscle-derived Wingless activates Akt in the neurons through the receptor tyrosine kinase Ror, which promotes the dendrite branching. In larval muscles, the expression of wingless is regulated not only in this key nutrient-dependent manner, but also by the JAK/STAT signaling pathway. Additionally, the low-yeast diet blunts neuronal light responsiveness and light avoidance behavior, which may help larvae optimize their survival strategies under low-nutritional conditions. Together, our studies illustrate how the availability of specific nutrients affects neuronal development through inter-organ signaling.
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Affiliation(s)
| | - Koun Onodera
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Kaori Watanabe
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Yusaku Hayashi
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Tadao Usui
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Tadashi Uemura
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
- Research Center for Dynamic Living Systems, Kyoto UniversityKyotoJapan
- AMED-CRESTTokyoJapan
| | - Yukako Hattori
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
- JST FORESTTokyoJapan
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2
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Gao Q, Deng H, Yang Z, Yang Q, Zhang Y, Yuan X, Zeng M, Guo M, Zeng W, Jiang X, Yu B. Sodium danshensu attenuates cerebral ischemia–reperfusion injury by targeting AKT1. Front Pharmacol 2022; 13:946668. [PMID: 36188542 PMCID: PMC9520076 DOI: 10.3389/fphar.2022.946668] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/22/2022] [Indexed: 12/02/2022] Open
Abstract
The beneficial properties of Sodium Danshensu (SDSS) for controlling cerebral ischemia and reperfusion injury (CIRI) are elucidated here both in vivo and in vitro. SDSS administration significantly improved the viability of P12 cells, reduced lactate dehydrogenase (LDH) leakage, and decreased the apoptosis rate following exposure to an oxygen-glucose deprivation/reoxygenation (OGD) environment. In addition, the results of a HuprotTM human protein microarray and network pharmacology indicated that AKT1 is one of the main targets of SDSS. Moreover, functional experiments showed that SDSS intervention markedly increased the phosphorylation level of AKT1 and its downstream regulator, mTOR. The binding sites of SDSS to AKT1 protein were confirmed by Autodock software and a surface plasmon resonance experiment, the result of which imply that SDSS targets to the PH domain of AKT1 at ASN-53, ARG-86, and LYS-14 residues. Furthermore, knockdown of AKT1 significantly abolished the role of SDSS in protecting cells from apoptosis and necrosis. Finally, we investigated the curative effect of SDSS in a rat model of CIRI. The results suggest that administration of SDSS significantly reduces CIRI-induced necrosis and apoptosis in brain samples by activating AKT1 protein. In conclusion, SDSS exerts its positive role in alleviating CIRI by binding to the PH domain of AKT1 protein, further resulting in AKT1 activation.
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Affiliation(s)
- Qing Gao
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hao Deng
- Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhengfei Yang
- College of Traditional Chinese Medicine, Ningxia Medical University, Yinchuan, China
| | - Qiuyue Yang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yilin Zhang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xiaopeng Yuan
- Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Miao Zeng
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Maojuan Guo
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Wenyun Zeng
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xijuan Jiang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- *Correspondence: Xijuan Jiang, ; Bin Yu,
| | - Bin Yu
- International Exchanges Department and International Education College, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- *Correspondence: Xijuan Jiang, ; Bin Yu,
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3
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PI(4,5)P2 controls slit diaphragm formation and endocytosis in Drosophila nephrocytes. Cell Mol Life Sci 2022; 79:248. [PMID: 35437696 PMCID: PMC9016003 DOI: 10.1007/s00018-022-04273-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 03/01/2022] [Accepted: 03/24/2022] [Indexed: 12/03/2022]
Abstract
Drosophila nephrocytes are an emerging model system for mammalian podocytes and proximal tubules as well as for the investigation of kidney diseases. Like podocytes, nephrocytes exhibit characteristics of epithelial cells, but the role of phospholipids in polarization of these cells is yet unclear. In epithelia, phosphatidylinositol(4,5)bisphosphate (PI(4,5)P2) and phosphatidylinositol(3,4,5)-trisphosphate (PI(3,4,5)P3) are asymmetrically distributed in the plasma membrane and determine apical–basal polarity. Here, we demonstrate that both phospholipids are present in the plasma membrane of nephrocytes, but only PI(4,5)P2 accumulates at slit diaphragms. Knockdown of Skittles, a phosphatidylinositol(4)phosphate 5-kinase, which produces PI(4,5)P2, abolished slit diaphragm formation and led to strongly reduced endocytosis. Notably, reduction in PI(3,4,5)P3 by overexpression of PTEN or expression of a dominant-negative phosphatidylinositol-3-kinase did not affect nephrocyte function, whereas enhanced formation of PI(3,4,5)P3 by constitutively active phosphatidylinositol-3-kinase resulted in strong slit diaphragm and endocytosis defects by ectopic activation of the Akt/mTOR pathway. Thus, PI(4,5)P2 but not PI(3,4,5)P3 is essential for slit diaphragm formation and nephrocyte function. However, PI(3,4,5)P3 has to be tightly controlled to ensure nephrocyte development.
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4
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Maines E, Franceschi R, Martinelli D, Soli F, Lepri FR, Piccoli G, Soffiati M. Hypoglycemia due to PI3K/AKT/mTOR signaling pathway defects: two novel cases and review of the literature. Hormones (Athens) 2021; 20:623-640. [PMID: 33876391 DOI: 10.1007/s42000-021-00287-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/25/2021] [Indexed: 12/30/2022]
Abstract
INTRODUCTION The PI3K/AKT/mTOR signaling pathway is important for the regulation of multiple biological processes, including cellular growth and glucose metabolism. Defects of the PI3K/AKT/mTOR signaling pathway are not usually considered among the genetic causes of recurrent hypoglycemia in childhood. However, accumulating evidence links hypoglycemia with defects of this pathway. CASE REPORTS AND REVIEW We describe here two cases of macrocephaly and hypoglycemia bearing genetic defects in genes involved in the PI3K/AKT/mTOR pathway. The first patient was diagnosed with a PTEN hamartoma tumour syndrome (PTHS) due to the de novo germline missense mutation c.[492 + 1G > A] of the PTEN gene. The second patient presented the autosomal dominant mental retardation-35 (MDR35) due to the heterozygous missense mutation c.592G > A in the PPP2R5D gene. A review of the literature on hypoglycemia and PI3K/AKT/mTOR signaling pathway defects, with a special focus on the metabolic characterization of hypoglycemia, is included. CONCLUSIONS PI3K/AKT/mTOR pathway defects should be included in the differential diagnosis of patients with hypoglycemia and macrocephaly. Clinical suspicion and molecular confirmation are important, not just for an accurate genetic counselling but also for defining the follow-up management, including cancer surveillance. The biochemical profile of hypoglycemia varies among patients. While most patients are characterized by low plasmatic insulin levels, hyperinsulinemia has also been observed. Large patient cohorts are needed to gain a comprehensive profile of the biochemical patterns of hypoglycemia in such defects and eventually guide targeted therapeutic interventions.
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Affiliation(s)
- Evelina Maines
- Division of Pediatrics, S. Chiara General Hospital, Largo Medaglie d'oro, 9, 38122, Trento, Italy.
| | - Roberto Franceschi
- Division of Pediatrics, S. Chiara General Hospital, Largo Medaglie d'oro, 9, 38122, Trento, Italy
| | - Diego Martinelli
- Division of Metabolism and Research Unit of Metabolic Biochemistry, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Fiorenza Soli
- Division of Medical Genetics, S. Chiara General Hospital, Trento, Italy
| | | | - Giovanni Piccoli
- CIBIO - Centre for Integrative Biology, Università Degli Studi Di Trento, Italy & Dulbecco Telethon Institute, Trento, Italy
| | - Massimo Soffiati
- Division of Pediatrics, S. Chiara General Hospital, Largo Medaglie d'oro, 9, 38122, Trento, Italy
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5
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Li M, Liu Y, Xie S, Ma L, Zhao Z, Gong H, Sun Y, Huang T. Transcriptome analysis reveals that long noncoding RNAs contribute to developmental differences between medium-sized ovarian follicles of Meishan and Duroc sows. Sci Rep 2021; 11:22510. [PMID: 34795345 PMCID: PMC8602415 DOI: 10.1038/s41598-021-01817-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 11/01/2021] [Indexed: 01/04/2023] Open
Abstract
Ovulation rate is an extremely important factor affecting litter size in sows. It differs greatly among pig breeds with different genetic backgrounds. Long non-coding RNAs (lncRNAs) can regulate follicle development, granulosa cell growth, and hormone secretion, which in turn can affect sow litter size. In this study, we identified 3554 lncRNAs and 25,491 mRNAs in M2 follicles of Meishan and Duroc sows. The lncRNA sequence and open reading frame lengths were shorter than mRNAs, and lncRNAs had fewer exons, were less abundant, and more conserved than protein-coding RNAs. Furthermore, 201 lncRNAs were differentially expressed (DE) between breeds, and quantitative trait loci analysis of DE lncRNAs were performed. A total of 127 DE lncRNAs were identified in 119 reproduction trait-related loci. In addition, the potential target genes of lncRNAs in cis or trans configurations were predicted. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that some potential target genes were involved in follicular development and hormone secretion-related biological processes or pathways, such as progesterone biosynthetic process, estrogen metabolic process, ovarian steroidogenesis, and PI3K-Akt signaling pathway. Furthermore, we also screened 19 differentially expressed lncRNAs in the PI3K-Akt signaling pathway as candidates. This study provides new insights into the roles of lncRNAs in follicular growth and development in pigs.
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Affiliation(s)
- Mengxun Li
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
| | - Yi Liu
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
- Key Laboratory of Bio-Resources and Eco-Environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, 610064, China
| | - Su Xie
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
| | - Lipeng Ma
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
| | - Zhichao Zhao
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
- Guangxi Yangxiang Animal Husbandry Co. Ltd., Guangxi, Guigang, 537100, China
| | - Hongbin Gong
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
| | - Yishan Sun
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China
| | - Tao Huang
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China.
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6
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Millington JW, Brownrigg GP, Basner-Collins PJ, Sun Z, Rideout EJ. Genetic manipulation of insulin/insulin-like growth factor signaling pathway activity has sex-biased effects on Drosophila body size. G3 (BETHESDA, MD.) 2021; 11:jkaa067. [PMID: 33793746 PMCID: PMC8063079 DOI: 10.1093/g3journal/jkaa067] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/09/2020] [Indexed: 12/14/2022]
Abstract
In Drosophila raised in nutrient-rich conditions, female body size is approximately 30% larger than male body size due to an increased rate of growth and differential weight loss during the larval period. While the mechanisms that control this sex difference in body size remain incompletely understood, recent studies suggest that the insulin/insulin-like growth factor signaling pathway (IIS) plays a role in the sex-specific regulation of processes that influence body size during development. In larvae, IIS activity differs between the sexes, and there is evidence of sex-specific regulation of IIS ligands. Yet, we lack knowledge of how changes to IIS activity impact body size in each sex, as the majority of studies on IIS and body size use single- or mixed-sex groups of larvae and/or adult flies. The goal of our current study was to clarify the body size requirement for IIS activity in each sex. To achieve this goal, we used established genetic approaches to enhance, or inhibit, IIS activity, and quantified pupal size in males and females. Overall, genotypes that inhibited IIS activity caused a female-biased decrease in body size, whereas genotypes that augmented IIS activity caused a male-specific increase in body size. These data extend our current understanding of body size regulation by showing that most changes to IIS pathway activity have sex-biased effects, and highlights the importance of analyzing body size data according to sex.
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Affiliation(s)
- Jason W Millington
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - George P Brownrigg
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Paige J Basner-Collins
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ziwei Sun
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Elizabeth J Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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7
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Abstract
The field of phosphoinositide signaling has expanded significantly in recent years. Phosphoinositides (also known as phosphatidylinositol phosphates or PIPs) are universal signaling molecules that directly interact with membrane proteins or with cytosolic proteins containing domains that directly bind phosphoinositides and are recruited to cell membranes. Through the activities of phosphoinositide kinases and phosphoinositide phosphatases, seven distinct phosphoinositide lipid molecules are formed from the parent molecule, phosphatidylinositol. PIP signals regulate a wide range of cellular functions, including cytoskeletal assembly, membrane budding and fusion, ciliogenesis, vesicular transport, and signal transduction. Given the many excellent reviews on phosphoinositide kinases, phosphoinositide phosphatases, and PIPs in general, in this review, we discuss recent studies and advances in PIP lipid signaling in the retina. We specifically focus on PIP lipids from vertebrate (e.g., bovine, rat, mouse, toad, and zebrafish) and invertebrate (e.g., Drosophila, horseshoe crab, and squid) retinas. We also discuss the importance of PIPs revealed from animal models and human diseases, and methods to study PIP levels both in vitro and in vivo. We propose that future studies should investigate the function and mechanism of activation of PIP-modifying enzymes/phosphatases and further unravel PIP regulation and function in the different cell types of the retina.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology, Physiology, and Cell Biology, and Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104.
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8
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Yu H, Yong W, Gao T, Na M, Zhang Y, Kuguminkiriza IH, Kenechukwu AA, Guo Q, Zhang G, Deng X. Hormesis of low-dose inhibition of pAkt1 (Ser473) followed by a great increase of proline-rich inositol polyphosphate 5-phosphatase (PIPP) level in oocytes. In Vitro Cell Dev Biol Anim 2021; 57:342-349. [PMID: 33537929 DOI: 10.1007/s11626-021-00546-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/06/2021] [Indexed: 10/22/2022]
Abstract
Hormesis describes a biphasic dose-response relationship generally characterized by a low-dose excitement and a high-dose inhibition. This phenomenon has been observed in the regulation of cell, organ, and organismic level. However, hormesis has not reported in oocytes. In this study, we observed, for the first time, hormetic responses of PIPP levels in oocytes by inhibitor of Akt1 or PKCδ. The expression of PIPP was detected by qPCR, immunofluorescent (IF), and Western Blot (WB). To observe the changes of PIPP levels, we used the inhibitors against pAkt1 (Ser473) or PKCδ, SH-6 or sotrastaurin with low and/or high-dose, treated GV oocytes and cultured for 4 h, respectively. The results showed that PIPP expression was significantly enhanced when oocytes were treated with SH-6 or sotrastaurin 10 μM, but decreased with SH-6 or sotrastaurin 100 μM. We also examined the changes of PIPP levels when GV oocytes were treated with exogenous PtdIns(3,4,5)P3 or LY294002 for 4 h. Our results showed that PIPP level was enhanced much higher under the treatment of 0.1 μM PtdIns(3,4,5)P3 than that of 1 μM PtdIns(3,4,5)P3, which is consistent with the changes of PIPP when oocytes were treated with inhibitors of pAkt1 (Ser473) or PKCδ. In addition, with PIPP siRNA, we detected that down-regulated PIPP may affect distributions of Akt, Cdc25, and pCdc2 (Tyr15). Taken together, these results show that the relationships between PIPP and Akt may follow the principle of hormesis and play a key role during release of diplotene arrest in mouse oocytes.
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Affiliation(s)
- Hang Yu
- Department of Physics and Biophysics, School of Fundamental Sciences, China Medical University (CMU), Shenyang, 110122, People's Republic of China
| | - Wei Yong
- Center Laboratory of the Fourth Affiliated Hospital, China Medical University (CMU), Shenyang, 110032, People's Republic of China
| | - Teng Gao
- Center Laboratory of the Fourth Affiliated Hospital, China Medical University (CMU), Shenyang, 110032, People's Republic of China
| | - Man Na
- Center Laboratory of the Fourth Affiliated Hospital, China Medical University (CMU), Shenyang, 110032, People's Republic of China
| | - Ye Zhang
- Center Laboratory of the Fourth Affiliated Hospital, China Medical University (CMU), Shenyang, 110032, People's Republic of China
| | | | | | - Qingguo Guo
- Department of Biochemistry and Molecular Biology, CMU, Shenyang, China
| | - Guoli Zhang
- Institute of Veterinary Medicine, The Academy of Military Medical Sciences of PLA, Changchun, 130122, Jilin, People's Republic of China
| | - Xin Deng
- Center Laboratory of the Fourth Affiliated Hospital, China Medical University (CMU), Shenyang, 110032, People's Republic of China.
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9
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Ho CH, Treisman JE. Specific Isoforms of the Guanine-Nucleotide Exchange Factor dPix Couple Neuromuscular Synapse Growth to Muscle Growth. Dev Cell 2020; 54:117-131.e5. [PMID: 32516570 DOI: 10.1016/j.devcel.2020.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 04/09/2020] [Accepted: 05/13/2020] [Indexed: 12/28/2022]
Abstract
Developmental growth requires coordination between the growth rates of individual tissues and organs. Here, we examine how Drosophila neuromuscular synapses grow to match the size of their target muscles. We show that changes in muscle growth driven by autonomous modulation of insulin receptor signaling produce corresponding changes in synapse size, with each muscle affecting only its presynaptic motor neuron branches. This scaling growth is mechanistically distinct from synaptic plasticity driven by neuronal activity and requires increased postsynaptic differentiation induced by insulin receptor signaling in muscle. We identify the guanine-nucleotide exchange factor dPix as an effector of insulin receptor signaling. Alternatively spliced dPix isoforms that contain a specific exon are necessary and sufficient for postsynaptic differentiation and scaling growth, and their mRNA levels are regulated by insulin receptor signaling. These findings define a mechanism by which the same signaling pathway promotes both autonomous muscle growth and non-autonomous synapse growth.
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Affiliation(s)
- Cheuk Hei Ho
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
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10
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Wang X, Liu M, Zhu MJ, Shi L, Liu L, Zhao YL, Cheng L, Gu YJ, Zhou MY, Chen L, Kumar A, Wang Y. Resveratrol protects the integrity of alveolar epithelial barrier via SIRT1/PTEN/p-Akt pathway in methamphetamine-induced chronic lung injury. Cell Prolif 2020; 53:e12773. [PMID: 32020692 PMCID: PMC7106965 DOI: 10.1111/cpr.12773] [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: 09/05/2019] [Revised: 12/22/2019] [Accepted: 01/09/2020] [Indexed: 12/17/2022] Open
Abstract
Objectives SIRT1 is an antioxidative factor, but its mechanism in methamphetamine (MA)‐induced lung injury remains unclear. The purpose of this study is to determine whether MA can disrupt the integrity of alveolar epithelial barrier, whether SIRT1 is involved in MA‐induced chronic lung injury and whether Resveratrol (Res) can protect the integrity of alveolar epithelial cells by regulating ROS to activate SIRT1/PTEN/p‐Akt pathway. Materials and methods The rats were randomly divided into control group and MA group. Extracted lungs were detected by Western blot, HE staining and immunohistochemistry. The alveolar epithelial cells were treated with MA or/and Res, following by Western blot, LDH leakage assay and flow cytometry. MOE is used for bio‐informatics prediction. Results Chronic exposure to MA can cause slower growth ratio of weight, increased RVI and induced lung injury including the reduced number of alveolar sacs and the thickened alveolar walls. MA‐induced apoptosis was associated with SIRT1‐related oxidative stress. Res suppressed ROS levels, activated SIRT1, negatively regulated PTEN, phosphorylated Akt, reduced LDH leakage, increased the expression of ZO‐1 and E‐cadherin and inhibited the apoptosis of alveolar epithelial cells to attenuate MA‐induced higher permeability of alveolar epithelium. Conclusions MA disrupted the integrity of alveolar epithelial barrier. Res inhibited oxidative stress and reversed MA‐induced higher permeability and apoptosis of alveolar epithelium by the activation of SIRT1/PTEN/p‐Akt pathway.
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Affiliation(s)
- Xin Wang
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Ming Liu
- Department of Drug Control, Criminal Investigation Police, University of China, Shenyang, China
| | - Mei-Jia Zhu
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Lin Shi
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Lian Liu
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Yuan-Ling Zhao
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Lin Cheng
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Ying-Jian Gu
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Ming-Yuan Zhou
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Lei Chen
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Ashok Kumar
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, TX, USA
| | - Yun Wang
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
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11
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Kierdorf K, Hersperger F, Sharrock J, Vincent CM, Ustaoglu P, Dou J, Gyoergy A, Groß O, Siekhaus DE, Dionne MS. Muscle function and homeostasis require cytokine inhibition of AKT activity in Drosophila. eLife 2020; 9:e51595. [PMID: 31944178 PMCID: PMC6996930 DOI: 10.7554/elife.51595] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/10/2020] [Indexed: 12/20/2022] Open
Abstract
Unpaired ligands are secreted signals that act via a GP130-like receptor, domeless, to activate JAK/STAT signalling in Drosophila. Like many mammalian cytokines, unpaireds can be activated by infection and other stresses and can promote insulin resistance in target tissues. However, the importance of this effect in non-inflammatory physiology is unknown. Here, we identify a requirement for unpaired-JAK signalling as a metabolic regulator in healthy adult Drosophila muscle. Adult muscles show basal JAK-STAT signalling activity in the absence of any immune challenge. Plasmatocytes (Drosophila macrophages) are an important source of this tonic signal. Loss of the dome receptor on adult muscles significantly reduces lifespan and causes local and systemic metabolic pathology. These pathologies result from hyperactivation of AKT and consequent deregulation of metabolism. Thus, we identify a cytokine signal that must be received in muscle to control AKT activity and metabolic homeostasis.
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Affiliation(s)
- Katrin Kierdorf
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUnited Kingdom
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Fabian Hersperger
- Institute of Neuropathology, Faculty of MedicineUniversity of FreiburgFreiburgGermany
- Faculty of BiologyUniversity of FreiburgFreiburgGermany
| | - Jessica Sharrock
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUnited Kingdom
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Crystal M Vincent
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUnited Kingdom
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Pinar Ustaoglu
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUnited Kingdom
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Jiawen Dou
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUnited Kingdom
| | - Attila Gyoergy
- Institute of Science and TechnologyKlosterneuburgAustria
| | - Olaf Groß
- Institute of Neuropathology, Faculty of MedicineUniversity of FreiburgFreiburgGermany
- Centre for Integrative Biological Signalling Studies (CIBSS)University of FreiburgFreiburgGermany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of MedicineUniversity of FreiburgFreiburgGermany
| | | | - Marc S Dionne
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUnited Kingdom
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12
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The many substrates and functions of NEDD4-1. Cell Death Dis 2019; 10:904. [PMID: 31787758 PMCID: PMC6885513 DOI: 10.1038/s41419-019-2142-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/24/2019] [Accepted: 11/12/2019] [Indexed: 01/08/2023]
Abstract
Tumorigenesis, tumor growth, and prognosis are highly related to gene alterations and post-translational modifications (PTMs). Ubiquitination is a critical PTM that governs practically all aspects of cellular function. An increasing number of studies show that E3 ubiquitin ligases (E3s) are important enzymes in the process of ubiquitination that primarily determine substrate specificity and thus need to be tightly controlled. Among E3s, neural precursor cell expressed developmentally downregulated 4-1 (NEDD4-1) has been shown to play a critical role in modulating the proliferation, migration, and invasion of cancer cells and the sensitivity of cancer cells to anticancer therapies via regulating multiple substrates. This review discusses some significant discoveries on NEDD4-1 substrates and the signaling pathways in which NEDD4-1 participates. In addition, we introduce the latest potential therapeutic strategies that inhibit or activate NEDD4-1 activity using small molecules. NEDD4-1 likely acts as a novel drug target or diagnostic marker in the battle against cancer.
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Identification of Key Transcription Factors AP-1 and AP-1-Dependent miRNAs Forming a Co-Regulatory Network Controlling PTEN in Liver Ischemia/Reperfusion Injury. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8962682. [PMID: 31781649 PMCID: PMC6875376 DOI: 10.1155/2019/8962682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/07/2019] [Accepted: 07/18/2019] [Indexed: 11/18/2022]
Abstract
Liver ischemia/reperfusion (I/R) injury is a complex and common clinical disease with limited therapeutic options. The aim of our study was to discover the candidate target genes in liver I/R injury and to further elucidate the potential regulatory mechanisms, especially the ones involving transcription factors and miRNAs. The analysis of mouse data set GSE10657 from Gene Expression Omnibus database (GEO) revealed 203 differentially expressed genes (DEGs) including 19 transcription factors (TFs). Functional and pathway enrichment analyses were conducted to explore their biological functions. We further obtained the targets of TFs and miRNAs, to form our TF-mRNA/TF-miRNA-mRNA co-regulatory network. In our network, we found that the important subunits of activator protein 1 (AP-1) including JUN, FOS and ATF3, were hub genes in liver I/R injury. AP-1 target genes were activated in our mouse models. AP-1 could transcriptionally activate phosphatase and tensin homolog (PTEN) while AP-1-dependent miRNAs countered this effect. In conclusion, this study suggested that AP-1, together with AP-1-dependent miRNAs formed a co-regulatory network enabling AP-1 target genes to be tightly controlled, which will complete the mechanism of liver ischemia/reperfusion injury and provide direction for finding potential therapeutic targets.
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Borreguero-Muñoz N, Fletcher GC, Aguilar-Aragon M, Elbediwy A, Vincent-Mistiaen ZI, Thompson BJ. The Hippo pathway integrates PI3K-Akt signals with mechanical and polarity cues to control tissue growth. PLoS Biol 2019; 17:e3000509. [PMID: 31613895 PMCID: PMC6814241 DOI: 10.1371/journal.pbio.3000509] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 10/25/2019] [Accepted: 10/03/2019] [Indexed: 11/19/2022] Open
Abstract
The Hippo signalling pathway restricts cell proliferation in animal tissues by inhibiting Yes-associated protein (YAP or YAP1) and Transcriptional Activator with a PDZ domain (TAZ or WW-domain-containing transcriptional activator [WWTR1]), coactivators of the Scalloped (Sd or TEAD) DNA-binding transcription factor. Drosophila has a single YAP/TAZ homolog named Yorkie (Yki) that is regulated by Hippo pathway signalling in response to epithelial polarity and tissue mechanics during development. Here, we show that Yki translocates to the nucleus to drive Sd-mediated cell proliferation in the ovarian follicle cell epithelium in response to mechanical stretching caused by the growth of the germline. Importantly, mechanically induced Yki nuclear localisation also requires nutritionally induced insulin/insulin-like growth factor 1 (IGF-1) signalling (IIS) via phosphatidyl inositol-3-kinase (PI3K), phosphoinositide-dependent kinase 1 (PDK1 or PDPK1), and protein kinase B (Akt or PKB) in the follicular epithelium. We find similar results in the developing Drosophila wing, where Yki becomes nuclear in the mechanically stretched cells of the wing pouch during larval feeding, which induces IIS, but translocates to the cytoplasm upon cessation of feeding in the third instar stage. Inactivating Akt prevents nuclear Yki localisation in the wing disc, while ectopic activation of the insulin receptor, PI3K, or Akt/PKB is sufficient to maintain nuclear Yki in mechanically stimulated cells of the wing pouch even after feeding ceases. Finally, IIS also promotes YAP nuclear localisation in response to mechanical cues in mammalian skin epithelia. Thus, the Hippo pathway has a physiological function as an integrator of epithelial cell polarity, tissue mechanics, and nutritional cues to control cell proliferation and tissue growth in both Drosophila and mammals.
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Affiliation(s)
| | - Georgina C. Fletcher
- Epithelial Biology Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Mario Aguilar-Aragon
- Epithelial Biology Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Ahmed Elbediwy
- Epithelial Biology Laboratory, The Francis Crick Institute, London, United Kingdom
| | | | - Barry J. Thompson
- Epithelial Biology Laboratory, The Francis Crick Institute, London, United Kingdom
- EMBL Australia, Department of Cancer Biology & Therapeutics, The John Curtin School of Medical Research, The Australian National University, Acton, Australia
- * E-mail:
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15
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Tian G, Chen J, Luo Y, Yang J, Gao T, Shi J. Ethanol extract of Ligustrum lucidum Ait. leaves suppressed hepatocellular carcinoma in vitro and in vivo. Cancer Cell Int 2019; 19:246. [PMID: 31572063 PMCID: PMC6761729 DOI: 10.1186/s12935-019-0960-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/13/2019] [Indexed: 12/15/2022] Open
Abstract
Background The present study investigated the pharmacological activity and mechanism of ethanol extract of Ligustrum lucidum Ait. leaves (EEL) on HCC. Methods Cell viability was determined using cell counting kit-8 (CCK-8) assay. The effects of EEL on cellular biological activities were analyzed by flow cytometry (FCM), cell wound scratch assay and transwell assay. The expression levels of related mRNA and protein were determined by performing quantitative real-time PCR (qRT-PCR), Western blotting assay and immunocytochemistry. Methylation-specific PCR (MSP) was carried out to investigate the possible mechanism underlying the DNA methylation of PTEN. Results EEL showed cytotoxicity to both Bel-7402 and Huh-7 cell lines. We also found that EEL enhanced the apoptosis of Bel-7402 and Huh-7 cells by regulating the expressions of Bcl-2 associated X (Bax), B cell lymphoma 2 (Bcl-2) and Cytochrome-C and the activity of caspase-3 and therefore promoted cell cycle arrest. Moreover, EEL also suppressed cell migration and invasion. EEL increased the expression of tissue inhibitor of metalloproteinases 2 (TIMP2) but decreased the expressions of matrix metalloproteinase2 (MMP2) and MMP9. Furthermore, EEL inhibited the phosphorylation of PI3K/Akt pathway. MSP results showed that EEL promoted the demethylation of PTEN, suggesting that the inactivation of PI3K/Akt may be related to DNA de-methylation of PTEN. In addition, EEL inhibited the tumor growth of HCC in vivo. Conclusions EEL exerted anti-tumor effect on HCC in vitro and in vivo. EEL mediated by the inhibition of PI3K/Akt may be closely related to DNA de-methylation of PTEN. Thus, EEL could be used as a potential anti-cancer therapeutic agent of HCC.
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Affiliation(s)
- Guoyan Tian
- 1Department of Oncology and Hematology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang Province China
| | - Jin Chen
- 2The Fourth Clinical Medical College, Zhejiang Chinese Medicine University, Hangzhou, Zhejiang Province China
| | - Yan Luo
- 3Institute of Translational Medicine, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang Province China
| | - Jin Yang
- 3Institute of Translational Medicine, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang Province China
| | - Tao Gao
- 4TCM Gynecology, Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou, Zhejiang Province China
| | - Junping Shi
- 5Department of Liver Diseases, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang Province China
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Heenatigala Palliyage G, Singh S, Ashby CR, Tiwari AK, Chauhan H. Pharmaceutical Topical Delivery of Poorly Soluble Polyphenols: Potential Role in Prevention and Treatment of Melanoma. AAPS PharmSciTech 2019; 20:250. [PMID: 31297635 DOI: 10.1208/s12249-019-1457-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 06/06/2019] [Indexed: 01/10/2023] Open
Abstract
Melanoma is regarded as the fifth and sixth most common cancer in men and women, respectively, and it is estimated that one person dies from melanoma every hour in the USA. Unfortunately, the treatment of melanoma is difficult because of its aggressive metastasis and resistance to treatment. The treatment of melanoma continues to be a challenging issue due to the limitations of available treatments such as a low response rate, severe adverse reactions, and significant toxicity. Natural polyphenols have attracted considerable attention from the scientific community due to their chemopreventive and chemotherapeutic efficacy. It has been suggested that poorly soluble polyphenols such as curcumin, resveratrol, quercetin, coumarin, and epigallocatechin-3-gallate may have significant benefits in the treatment of melanoma due to their antioxidant, anti-inflammatory, antiproliferative, and chemoprotective efficacies. The major obstacles for the use of polyphenolic compounds are low stability and poor bioavailability. Numerous nanoformulations, including solid lipid nanoparticles, polymeric nanoparticles, micelles, and liposomes, have been formulated to enhance the bioavailability and stability, as well as the therapeutic efficacy of polyphenols. This review will provide an overview of poorly soluble polyphenols that have been reported to have antimetastatic efficacy in melanomas.
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Grewal AK, Singh N, Singh TG. Neuroprotective effect of pharmacological postconditioning on cerebral ischaemia-reperfusion-induced injury in mice. ACTA ACUST UNITED AC 2019; 71:956-970. [PMID: 30809806 DOI: 10.1111/jphp.13073] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/01/2019] [Indexed: 12/31/2022]
Abstract
OBJECTIVES To investigate the mechanism of neuroprotection rendered via pharmacological postconditioning in cerebral ischaemia-reperfusion-induced injury in mice. METHODS Pharmacological postconditioning is strategy which either involves hindering deleterious pathway or inducing modest stress level which triggers intracellular defence pathway to sustain more vigorous insult leading to conditioning. Hence, in current research we explored the potentiality of CGS21680 (0.5 mg/kg; i.p), an adenosine A2 A receptor agonist and PTEN inhibitor, SF1670 (3 mg/kg; i.p.) to trigger postconditioning after inducing cerebral global ischaemia (17 min) and reperfusion (24 h)-induced injury via occlusion of both carotid arteries. Mice were also given treatment with LY294002 (1.5 mg/kg; i.p.), a PI3K inhibitor and adenosine A2 A receptor antagonist, Istradefylline (2 mg/kg; i.p.), to establish the precise mechanism of postconditioning. Various biochemical and behavioural parameters were assessed to examine the effect of pharmacological postconditioning. KEY FINDINGS Pharmacological postconditioning induced with CGS21680 and SF1670 attenuated the infarction along with improved behavioural and biochemical parameters in comparison with ischaemia-reperfusion control group. The outcome of postconditioning with CGS21680 and SF1670 was significantly reversed by LY294002 and Istradefylline, respectively. CONCLUSIONS The neuroprotective effects of CGS21680 and SF1670 postconditioning on cerebral ischaemia-reperfusion injury may be due to PI3K/Akt pathway activation.
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Affiliation(s)
- Amarjot Kaur Grewal
- Department of Pharmacology, Chitkara college of Pharmacy, Chitkara University, Patiala, India
| | - Nirmal Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India
| | - Thakur Gurjeet Singh
- Department of Pharmacology, Chitkara college of Pharmacy, Chitkara University, Patiala, India
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Ask1 and Akt act synergistically to promote ROS-dependent regeneration in Drosophila. PLoS Genet 2019; 15:e1007926. [PMID: 30677014 PMCID: PMC6363233 DOI: 10.1371/journal.pgen.1007926] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 02/05/2019] [Accepted: 01/01/2019] [Indexed: 12/30/2022] Open
Abstract
How cells communicate to initiate a regenerative response after damage has captivated scientists during the last few decades. It is known that one of the main signals emanating from injured cells is the Reactive Oxygen Species (ROS), which propagate to the surrounding tissue to trigger the replacement of the missing cells. However, the link between ROS production and the activation of regenerative signaling pathways is not yet fully understood. We describe here the non-autonomous ROS sensing mechanism by which living cells launch their regenerative program. To this aim, we used Drosophila imaginal discs as a model system due to its well-characterized regenerative ability after injury or cell death. We genetically-induced cell death and found that the Apoptosis signal-regulating kinase 1 (Ask1) is essential for regenerative growth. Ask1 senses ROS both in dying and living cells, but its activation is selectively attenuated in living cells by Akt1, the core kinase component of the insulin/insulin-like growth factor pathway. Akt1 phosphorylates Ask1 in a secondary site outside the kinase domain, which attenuates its activity. This modulation of Ask1 activity results in moderate levels of JNK signaling in the living tissue, as well as in activation of p38 signaling, both pathways required to turn on the regenerative response. Our findings demonstrate a non-autonomous activation of a ROS sensing mechanism by Ask1 and Akt1 to replace the missing tissue after damage. Collectively, these results provide the basis for understanding the molecular mechanism of communication between dying and living cells that triggers regeneration. One of the early events that occur after tissue damage consists on the production of Reactive Oxygen Species (ROS), that signal to the surrounding tissue to initiate wound healing and regeneration. Many signaling pathways, such as JNK and p38, respond to oxidative stress and are necessary for regenerative growth. As the link between ROS and regenerative signaling is not well understood, we decided to explore the mechanism that underlies this process. To do that, we genetically induced cell death in specific areas of Drosophila wing imaginal discs and then studied the mechanism that drives living cells to replace the damage zone until it is completely regenerated. We found that the Drosophila Apoptosis signal-regulating kinase 1 (Ask1), a protein that is sensitive to oxidative stress, is a key player in this scenario. This protein acts as an intracellular sensor that upon damage activates the JNK and p38 regenerative signaling pathways. However, high activity of Ask1 can be toxic for the cell. This is controlled by Akt, a kinase downstream the insulin pathway, which attenuates the activity of Ask1 in the living cells that will participate in the regeneration process. In consequence, Ask1 and Akt act synergistically to respond to the stress generated after tissue damage and drive regeneration. Our results provide a first overview within the framework of how insulin signaling inputs could modulate the capacity to overcome tissue damage.
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Zhao S, Wu L, Kuang Y, Su J, Luo Z, Wang Y, Li J, Zhang J, Chen W, Li F, He Y, Tao J, Zhou J, Xu X, Peng C, Chen X. Downregulation of CD147 induces malignant melanoma cell apoptosis via the regulation of IGFBP2 expression. Int J Oncol 2018; 53:2397-2408. [PMID: 30272281 PMCID: PMC6203154 DOI: 10.3892/ijo.2018.4579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/07/2018] [Indexed: 12/18/2022] Open
Abstract
Cluster of differentiation (CD)147, as a transmembrane glycoprotein, is highly expressed in a variety of tumors. Accumulating evidence has demonstrated that CD147 serves critical roles in tumor cell death and survival; however, the underlying mechanism requires further investigation. In the present study, it was revealed that CD147 knockdown significantly increased melanoma cell apoptosis. In addition, downregulation of CD147 reversed the malignant phenotype of melanoma, as demonstrated by the induction of tumor cell apoptosis in a xenograft mouse model. In addition, a human apoptosis antibody array was performed and 9 differentially expressed apoptosis-related proteins associated with CD147 were identified, including insulin-like growth factor-binding protein 2 (IGFBP2). Additionally, CD147 knockdown was observed to significantly decreased IGFBP2 expression at the mRNA and protein levels in melanoma cells. Providing that IGFBP2 is a downstream molecule in the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, the effects of CD147 on this particular pathway were investigated. Interestingly, the expression of phosphorylated (p)-AKT and p‑mechanistic target of rapamycin was attenuated, whereas PTEN was markedly upregulated in CD147-underexpressing melanoma cells. Furthermore, application of a PI3K‑specific inhibitor also decreased IGFBP2 expression. Importantly, IGFBP2 was highly expressed in clinical tissues of melanoma compared with the control group, and its expression exhibited a positive association with CD147. The present study revealed that CD147 served a critical role in mediating the apoptosis of melanoma cells via IGFBP2 and the PTEN/PI3K/AKT signaling pathway. IGFBP2 and CD147 were observed to be overexpressed in clinical melanoma tissues; IGFBP2 was shown to be positively associated with CD147 expression, suggesting that CD147 may be considered as a potential therapeutic target for chemotherapy or prevention for in melanoma.
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Affiliation(s)
- Shuang Zhao
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Lisha Wu
- Institute of Medical Sciences, Xiangya Hospital, Central South University, Changsha, Hunan 410008
| | - Yehong Kuang
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Juan Su
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Zhongling Luo
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Yan Wang
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, Jiangsu 210042
| | - Jinmao Li
- Department of Dermatology, Xiangya Hospital
| | - Jianglin Zhang
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Wangqing Chen
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Fangfang Li
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Yijing He
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Juan Tao
- Department of Dermatology, Affiliated Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030
| | - Jianda Zhou
- Department of Plastic Surgery of The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P. R. China
| | - Xiaowei Xu
- Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Cong Peng
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
| | - Xiang Chen
- Department of Dermatology, Xiangya Hospital
- Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital
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Courgeon M, He DQ, Liu HH, Legent K, Treisman JE. The Drosophila Epidermal Growth Factor Receptor does not act in the nucleus. J Cell Sci 2018; 131:jcs.220251. [PMID: 30158176 DOI: 10.1242/jcs.220251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/16/2018] [Indexed: 12/15/2022] Open
Abstract
Mammalian members of the ErbB family, including the epidermal growth factor receptor (EGFR), can regulate transcription, DNA replication and repair through nuclear entry of either the full-length proteins or their cleaved cytoplasmic domains. In cancer cells, these nuclear functions contribute to tumor progression and drug resistance. Here, we examined whether the single Drosophila EGFR can also localize to the nucleus. A chimeric EGFR protein fused at its cytoplasmic C-terminus to DNA-binding and transcriptional activation domains strongly activated transcriptional reporters when overexpressed in cultured cells or in vivo However, this activity was independent of cleavage and endocytosis. Without an exogenous activation domain, EGFR fused to a DNA-binding domain did not activate or repress transcription. Addition of the same DNA-binding and transcriptional activation domains to the endogenous Egfr locus through genome editing led to no detectable reporter expression in wild-type or oncogenic contexts. These results show that, when expressed at physiological levels, the cytoplasmic domain of the Drosophila EGFR does not have access to the nucleus. Therefore, nuclear EGFR functions are likely to have evolved after vertebrates and invertebrates diverged.
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Affiliation(s)
- Maximilien Courgeon
- Skirball Institute for Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Dan Qing He
- Skirball Institute for Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Hui Hua Liu
- Skirball Institute for Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Kevin Legent
- Skirball Institute for Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Jessica E Treisman
- Skirball Institute for Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
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Katsuyama T, Tsokos GC, Moulton VR. Aberrant T Cell Signaling and Subsets in Systemic Lupus Erythematosus. Front Immunol 2018; 9:1088. [PMID: 29868033 PMCID: PMC5967272 DOI: 10.3389/fimmu.2018.01088] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/01/2018] [Indexed: 12/20/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a chronic multi-organ debilitating autoimmune disease, which mainly afflicts women in the reproductive years. A complex interaction of genetics, environmental factors and hormones result in the breakdown of immune tolerance to "self" leading to damage and destruction of multiple organs, such as the skin, joints, kidneys, heart and brain. Both innate and adaptive immune systems are critically involved in the misguided immune response against self-antigens. Dendritic cells, neutrophils, and innate lymphoid cells are important in initiating antigen presentation and propagating inflammation at lymphoid and peripheral tissue sites. Autoantibodies produced by B lymphocytes and immune complex deposition in vital organs contribute to tissue damage. T lymphocytes are increasingly being recognized as key contributors to disease pathogenesis. CD4 T follicular helper cells enable autoantibody production, inflammatory Th17 subsets promote inflammation, while defects in regulatory T cells lead to unchecked immune responses. A better understanding of the molecular defects including signaling events and gene regulation underlying the dysfunctional T cells in SLE is necessary to pave the path for better management, therapy, and perhaps prevention of this complex disease. In this review, we focus on the aberrations in T cell signaling in SLE and highlight therapeutic advances in this field.
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Affiliation(s)
| | | | - Vaishali R. Moulton
- Division of Rheumatology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
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Nowak K, Gupta A, Stocker H. FoxO restricts growth and differentiation of cells with elevated TORC1 activity under nutrient restriction. PLoS Genet 2018; 14:e1007347. [PMID: 29677182 PMCID: PMC5931687 DOI: 10.1371/journal.pgen.1007347] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 05/02/2018] [Accepted: 03/30/2018] [Indexed: 11/19/2022] Open
Abstract
TORC1, a central regulator of cell survival, growth, and metabolism, is activated in a variety of cancers. Loss of the tumor suppressors PTEN and Tsc1/2 results in hyperactivation of TORC1. Tumors caused by the loss of PTEN, but not Tsc1/2, are often malignant and have been shown to be insensitive to nutrient restriction (NR). In Drosophila, loss of PTEN or Tsc1 results in hypertrophic overgrowth of epithelial tissues under normal nutritional conditions, and an enhanced TORC1-dependent hyperplastic overgrowth of PTEN mutant tissue under NR. Here we demonstrate that epithelial cells lacking Tsc1 or Tsc2 also acquire a growth advantage under NR. The overgrowth correlates with high TORC1 activity, and activating TORC1 downstream of Tsc1 by overexpression of Rheb is sufficient to enhance tissue growth. In contrast to cells lacking PTEN, Tsc1 mutant cells show decreased PKB activity, and the extent of Tsc1 mutant overgrowth is dependent on the loss of PKB-mediated inhibition of the transcription factor FoxO. Removal of FoxO function from Tsc1 mutant tissue induces massive hyperplasia, precocious differentiation, and morphological defects specifically under NR, demonstrating that FoxO activation is responsible for restricting overgrowth of Tsc1 mutant tissue. The activation status of FoxO may thus explain why tumors caused by the loss of Tsc1-in contrast to PTEN-rarely become malignant.
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Affiliation(s)
- Katarzyna Nowak
- Institute of Molecular Systems Biology, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, Switzerland
| | - Avantika Gupta
- Institute of Molecular Systems Biology, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, Switzerland
| | - Hugo Stocker
- Institute of Molecular Systems Biology, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, Switzerland
- * E-mail:
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Spéder P, Brand AH. Systemic and local cues drive neural stem cell niche remodelling during neurogenesis in Drosophila. eLife 2018; 7. [PMID: 29299997 PMCID: PMC5754201 DOI: 10.7554/elife.30413] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 12/13/2017] [Indexed: 12/21/2022] Open
Abstract
Successful neurogenesis requires adequate proliferation of neural stem cells (NSCs) and their progeny, followed by neuronal differentiation, maturation and survival. NSCs inhabit a complex cellular microenvironment, the niche, which influences their behaviour. To ensure sustained neurogenesis, niche cells must respond to extrinsic, environmental changes whilst fulfilling the intrinsic requirements of the neurogenic program and adapting their roles accordingly. However, very little is known about how different niche cells adjust their properties to such inputs. Here, we show that nutritional and NSC-derived signals induce the remodelling of Drosophila cortex glia, adapting this glial niche to the evolving needs of NSCs. First, nutrition-induced activation of PI3K/Akt drives the cortex glia to expand their membrane processes. Second, when NSCs emerge from quiescence to resume proliferation, they signal to glia to promote membrane remodelling and the formation of a bespoke structure around each NSC lineage. The remodelled glial niche is essential for newborn neuron survival.
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Affiliation(s)
- Pauline Spéder
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
| | - Andrea H Brand
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
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Jia M, Chen X, Liu J, Chen J. PTEN promotes apoptosis of H2O2‑injured rat nasal epithelial cells through PI3K/Akt and other pathways. Mol Med Rep 2017; 17:571-579. [PMID: 29115519 DOI: 10.3892/mmr.2017.7912] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 10/02/2017] [Indexed: 11/05/2022] Open
Abstract
Chronic rhinosinusitis (CRS) is a form of chronic inflammation of the nasal cavity and paranasal sinus with multi‑causal pathogenesis, including oxidative stress. Several lines of evidence have demonstrated that the phosphatase and tensin homolog gene (PTEN) can inhibit the activation of phosphoinositide 3‑kinase (PI3K) to affect phosphorylation of Akt. Importantly, the PI3K/PTEN/Akt signaling pathway is associated with various types of tumors, chronic inflammatory diseases, and autoimmune disease through its regulation of cell growth, apoptosis, proliferation, and metabolism. This in vitro study aimed to investigate the role of PTEN and the relationship between PTEN and the PI3K/Akt pathway in nasal epithelial cells under oxidative stress. H2O2 treatment was applied to induce a cell injury model of oxidative stress in rat nasal epithelial cells. Cells were divided into control, H2O2, H2O2+PTEN, and H2O2+siPTEN groups. Cell viability was measured using the CCK‑8 assay, and reactive oxygen species (ROS) levels and apoptosis rates were analyzed by flow cytometry (FCM). Oxidative parameters, including ROS, catalase (CAT), and malondialdehyde (MDA), were tested by enzyme‑linked immunosorbent assay (ELISA). The expression of apoptosis‑related genes and PI3K/Akt pathway was assayed by quantitative PCR (qPCR) and western blot. In H2O2‑injured cells, oxidative stress, due to increased ROS levels and apoptosis rates, was induced, and PTEN aggravated the injury. The levels of both p‑Akt and PTEN in H2O2‑injured cells were positively correlated and higher than in control cells. Unknown regulatory protein(s) may exist in the PI3K/PTEN/Akt pathway or the PTEN and PI3K/Akt pathways may be two independent signaling pathways that have cross interactions.
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Affiliation(s)
- Minghui Jia
- Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Xiaoyun Chen
- Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Jili Liu
- Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Jun Chen
- Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
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Prostate cancer, PI3K, PTEN and prognosis. Clin Sci (Lond) 2017; 131:197-210. [PMID: 28057891 DOI: 10.1042/cs20160026] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/12/2016] [Accepted: 11/21/2016] [Indexed: 12/22/2022]
Abstract
Loss of function of the PTEN tumour suppressor, resulting in dysregulated activation of the phosphoinositide 3-kinase (PI3K) signalling network, is recognized as one of the most common driving events in prostate cancer development. The observed mechanisms of PTEN loss are diverse, but both homozygous and heterozygous genomic deletions including PTEN are frequent, and often accompanied by loss of detectable protein as assessed by immunohistochemistry (IHC). The occurrence of PTEN loss is highest in aggressive metastatic disease and this has driven the development of PTEN as a prognostic biomarker, either alone or in combination with other factors, to distinguish indolent tumours from those likely to progress. Here, we discuss these factors and the consequences of PTEN loss, in the context of its role as a lipid phosphatase, as well as current efforts to use available inhibitors of specific components of the PI3K/PTEN/TOR signalling network in prostate cancer treatment.
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Cinnamon E, Makki R, Sawala A, Wickenberg LP, Blomquist GJ, Tittiger C, Paroush Z, Gould AP. Drosophila Spidey/Kar Regulates Oenocyte Growth via PI3-Kinase Signaling. PLoS Genet 2016; 12:e1006154. [PMID: 27500738 PMCID: PMC4976899 DOI: 10.1371/journal.pgen.1006154] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 06/08/2016] [Indexed: 11/19/2022] Open
Abstract
Cell growth and proliferation depend upon many different aspects of lipid metabolism. One key signaling pathway that is utilized in many different anabolic contexts involves Phosphatidylinositide 3-kinase (PI3K) and its membrane lipid products, the Phosphatidylinositol (3,4,5)-trisphosphates. It remains unclear, however, which other branches of lipid metabolism interact with the PI3K signaling pathway. Here, we focus on specialized fat metabolizing cells in Drosophila called larval oenocytes. In the presence of dietary nutrients, oenocytes undergo PI3K-dependent cell growth and contain very few lipid droplets. In contrast, during starvation, oenocytes decrease PI3K signaling, shut down cell growth and accumulate abundant lipid droplets. We now show that PI3K in larval oenocytes, but not in fat body cells, functions to suppress lipid droplet accumulation. Several enzymes of fatty acid, triglyceride and hydrocarbon metabolism are required in oenocytes primarily for lipid droplet induction rather than for cell growth. In contrast, a very long chain fatty-acyl-CoA reductase (FarO) and a putative lipid dehydrogenase/reductase (Spidey, also known as Kar) not only promote lipid droplet induction but also inhibit oenocyte growth. In the case of Spidey/Kar, we show that the growth suppression mechanism involves inhibition of the PI3K signaling pathway upstream of Akt activity. Together, the findings in this study show how Spidey/Kar and FarO regulate the balance between the cell growth and lipid storage of larval oenocytes. Lipids play diverse roles in health and disease. Some types of lipids function as metabolic fuels for energy homeostasis, whereas others act as components of cell membranes or serve as signals regulating cell behaviors. Much, however, remains to be discovered about the molecular connections between different categories of lipids. Phosphatidylinositide 3-kinase (PI3K) is an enzyme that synthesizes phosphatidylinositide lipids, which act as signals essential for growth during normal development and cancer. Using genetics in the fruit fly, Drosophila, we identify new regulatory links between phosphatidylinositides and lipid oxidoreductases in specialized fat-metabolizing cells called oenocytes. We find that an enzyme metabolizing very long chain fatty acids (VLCFAs) and also a putative lipid dehydrogenase/reductase both act to prevent the inappropriate overgrowth of oenocytes. In the case of the latter enzyme, it suppresses cell growth by inhibiting phosphatidylinositide signaling. Future studies will determine whether similar lipid enzymes regulate PI3K signaling in other cell and tissue types during normal development and tumorigenesis.
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Affiliation(s)
- Einat Cinnamon
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, United Kingdom
| | - Rami Makki
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, United Kingdom
| | - Annick Sawala
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, United Kingdom
| | - Leah P. Wickenberg
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, Nevada, United States of America
| | - Gary J. Blomquist
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, Nevada, United States of America
| | - Claus Tittiger
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, Nevada, United States of America
| | - Ze'ev Paroush
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, the Hebrew University, Jerusalem, Israel
| | - Alex P. Gould
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, United Kingdom
- * E-mail:
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Chang YJ, Zhou L, Binari R, Manoukian A, Mak T, McNeill H, Stambolic V. The Rho Guanine Nucleotide Exchange Factor DRhoGEF2 Is a Genetic Modifier of the PI3K Pathway in Drosophila. PLoS One 2016; 11:e0152259. [PMID: 27015411 PMCID: PMC4807833 DOI: 10.1371/journal.pone.0152259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 03/13/2016] [Indexed: 01/14/2023] Open
Abstract
The insulin/IGF-1 signaling pathway mediates various physiological processes associated with human health. Components of this pathway are highly conserved throughout eukaryotic evolution. In Drosophila, the PTEN ortholog and its mammalian counterpart downregulate insulin/IGF signaling by antagonizing the PI3-kinase function. From a dominant loss-of-function genetic screen, we discovered that mutations of a Dbl-family member, the guanine nucleotide exchange factor DRhoGEF2 (DRhoGEF22(l)04291), suppressed the PTEN-overexpression eye phenotype. dAkt/dPKB phosphorylation, a measure of PI3K signaling pathway activation, increased in the eye discs from the heterozygous DRhoGEF2 wandering third instar larvae. Overexpression of DRhoGEF2, and it’s functional mammalian ortholog PDZ-RhoGEF (ArhGEF11), at various stages of eye development, resulted in both dPKB/Akt-dependent and -independent phenotypes, reflecting the complexity in the crosstalk between PI3K and Rho signaling in Drosophila.
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Affiliation(s)
- Ying-Ju Chang
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
| | - Lily Zhou
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
| | - Richard Binari
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
| | - Armen Manoukian
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
| | - Tak Mak
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Helen McNeill
- Lunenfeld-Tanenbaum Research Institute/Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Vuk Stambolic
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- * E-mail:
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Zhang R, Zhu L, Zhang L, Xu A, Li Z, Xu Y, He P, Wu M, Wei F, Wang C. PTEN enhances G2/M arrest in etoposide-treated MCF‑7 cells through activation of the ATM pathway. Oncol Rep 2016; 35:2707-14. [PMID: 26986476 DOI: 10.3892/or.2016.4674] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 12/27/2015] [Indexed: 11/06/2022] Open
Abstract
As an effective tumor suppressor, phosphatase and tensin homolog (PTEN) has attracted the increased attention of scientists. Recent studies have shown that PTEN plays unique roles in the DNA damage response (DDR) and can interact with the Chk1 pathway. However, little is known about how PTEN contributes to DDR through the ATM-Chk2 pathway. It is well-known that etoposide induces G2/M arrest in a variety of cell lines, including MCF-7 cells. The DNA damage-induced G2/M arrest results from the activation of protein kinase ataxia telangiectasia mutated (ATM), followed by the activation of Chk2 that subsequently inactivates CDC25C, resulting in G2/M arrest. In the present study, we assessed the contribution of PTEN to the etoposide-induced G2/M cell cycle arrest. PTEN was knocked down in MCF-7 cells by specific shRNA, and the effects of PTEN on the ATM-Chk2 pathway were investigated through various approaches. The results showed that knockdown of PTEN strongly antagonized ATM activation in response to etoposide treatment, and thereby reduced the phosphorylation level of ATM substrates, including H2AX, P53 and Chk2. Furthermore, depletion of PTEN reduced the etoposide-induced phosphorylation of CDC25C and strikingly compromised etoposide-induced G2/M arrest in the MCF-7 cells. Altogether, we demonstrated that PTEN plays a unique role in etoposide-induced G2/M arrest by facilitating the activation of the ATM pathway, and PTEN was required for the proper activation of checkpoints in response to DNA damage in MCF-7 cells.
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Affiliation(s)
- Ruopeng Zhang
- Department of Obstetrics and Gynecology, Shenzhen Maternity and Child Healthcare Hospital, Affiliated to Southern Medical University, Longgang, Shenzhen, Guangdong 518028, P.R. China
| | - Li Zhu
- Department of Reproductive Medicine, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China
| | - Lirong Zhang
- Department of Reproductive Medicine, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China
| | - Anli Xu
- Department of Reproductive Medicine, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China
| | - Zhengwei Li
- Clinical Medicine College of Dali University, Dali, Yunnan 671000, P.R. China
| | - Yijuan Xu
- Clinical Medicine College of Dali University, Dali, Yunnan 671000, P.R. China
| | - Pei He
- Clinical Medicine College of Dali University, Dali, Yunnan 671000, P.R. China
| | - Maoqing Wu
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Fengxiang Wei
- The Genetics Laboratory, Shenzhen Longgang District Maternity and Child Healthcare Hospital, Longgang, Shenzhen, Guangdong 518028, P.R. China
| | - Chenhong Wang
- Department of Obstetrics and Gynecology, Shenzhen Maternity and Child Healthcare Hospital, Affiliated to Southern Medical University, Longgang, Shenzhen, Guangdong 518028, P.R. China
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Rajagopalan P, Alahmari KA, Elbessoumy AA, Balasubramaniam M, Suresh R, Shariff MEA, Chandramoorthy HC. Biological evaluation of 2-arylidene-4, 7-dimethyl indan-1-one (FXY-1): a novel Akt inhibitor with potent activity in lung cancer. Cancer Chemother Pharmacol 2016; 77:393-404. [DOI: 10.1007/s00280-015-2956-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/29/2015] [Indexed: 12/24/2022]
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Computational Analysis of the Binding Specificities of PH Domains. BIOMED RESEARCH INTERNATIONAL 2015; 2015:792904. [PMID: 26881206 PMCID: PMC4735990 DOI: 10.1155/2015/792904] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/13/2015] [Accepted: 12/17/2015] [Indexed: 12/15/2022]
Abstract
Pleckstrin homology (PH) domains share low sequence identities but extremely conserved structures. They have been found in many proteins for cellular signal-dependent membrane targeting by binding inositol phosphates to perform different physiological functions. In order to understand the sequence-structure relationship and binding specificities of PH domains, quantum mechanical (QM) calculations and sequence-based combined with structure-based binding analysis were employed in our research. In the structural aspect, the binding specificities were shown to correlate with the hydropathy characteristics of PH domains and electrostatic properties of the bound inositol phosphates. By comparing these structure properties with sequence-based profiles of physicochemical properties, PH domains can be classified into four functional subgroups according to their binding specificities and affinities to inositol phosphates. The method not only provides a simple and practical paradigm to predict binding specificities for functional genomic research but also gives new insight into the understanding of the basis of diseases with respect to PH domain structures.
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Abstract
Although emerging roles of protease-activated receptor1&2 (PAR1&2) in cancer are recognized, their underlying signalling events are poorly understood. Here we show signal-binding motifs in PAR1&2 that are critical for breast cancer growth. This occurs via the association of the pleckstrin homology (PH) domain with Akt/PKB as a key signalling event of PARs. Other PH-domain signal-proteins such as Etk/Bmx and Vav3 also associate with PAR1 and PAR2 through their PH domains. PAR1 and PAR2 bind with priority to Etk/Bmx. A point mutation in PAR2, H349A, but not in R352A, abrogates PH-protein association and is sufficient to markedly reduce PAR2-instigated breast tumour growth in vivo and placental extravillous trophoblast (EVT) invasion in vitro. Similarly, the PAR1 mutant hPar1-7A, which is unable to bind the PH domain, reduces mammary tumours and EVT invasion, endowing these motifs with physiological significance and underscoring the importance of these previously unknown PAR1 and PAR2 PH-domain-binding motifs in both pathological and physiological invasion processes. Protease-activated-receptor 1 and 2 (PAR1 and PAR2) are key players in tumor growth. In this study, the authors identify PAR1 and PAR2 domains that bind oncogenic signalling proteins driving breast cancer progression in vivo and placental extravillous trophoblast invasion in vitro.
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Mensah LB, Davison C, Fan SJ, Morris JF, Goberdhan DCI, Wilson C. Fine-Tuning of PI3K/AKT Signalling by the Tumour Suppressor PTEN Is Required for Maintenance of Flight Muscle Function and Mitochondrial Integrity in Ageing Adult Drosophila melanogaster. PLoS One 2015; 10:e0143818. [PMID: 26599788 PMCID: PMC4658134 DOI: 10.1371/journal.pone.0143818] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/09/2015] [Indexed: 11/24/2022] Open
Abstract
Insulin/insulin-like growth factor signalling (IIS), acting primarily through the PI3-kinase (PI3K)/AKT kinase signalling cassette, plays key evolutionarily conserved regulatory roles in nutrient homeostasis, growth, ageing and longevity. The dysfunction of this pathway has been linked to several age-related human diseases including cancer, Type 2 diabetes and neurodegenerative disorders. However, it remains unclear whether minor defects in IIS can independently induce the age-dependent functional decline in cells that accompany some of these diseases or whether IIS alters the sensitivity to other aberrant signalling. We identified a novel hypomorphic allele of PI3K’s direct antagonist, Phosphatase and tensin homologue on chromosome 10 (Pten), in the fruit fly, Drosophila melanogaster. Adults carrying combinations of this allele, Pten5, combined with strong loss-of-function Pten mutations exhibit subtle or no increase in mass, but are highly susceptible to a wide range of stresses. They also exhibit dramatic upregulation of the oxidative stress response gene, GstD1, and a progressive loss of motor function that ultimately leads to defects in climbing and flight ability. The latter phenotype is associated with mitochondrial disruption in indirect flight muscles, although overall muscle structure appears to be maintained. We show that the phenotype is partially rescued by muscle-specific expression of the Bcl-2 homologue Buffy, which in flies, maintains mitochondrial integrity, modulates energy homeostasis and suppresses cell death. The flightless phenotype is also suppressed by mutations in downstream IIS signalling components, including those in the mechanistic Target of Rapamycin Complex 1 (mTORC1) pathway, suggesting that elevated IIS is responsible for functional decline in flight muscle. Our data demonstrate that IIS levels must be precisely regulated by Pten in adults to maintain the function of the highly metabolically active indirect flight muscles, offering a new system to study the in vivo roles of IIS in the maintenance of mitochondrial integrity and adult ageing.
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Affiliation(s)
- Lawrence B. Mensah
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, United Kingdom
| | - Claire Davison
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, United Kingdom
| | - Shih-Jung Fan
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, United Kingdom
| | - John F. Morris
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, United Kingdom
| | - Deborah C. I. Goberdhan
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, United Kingdom
| | - Clive Wilson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, United Kingdom
- * E-mail:
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Kriplani N, Hermida MA, Brown ER, Leslie NR. Class I PI 3-kinases: Function and evolution. Adv Biol Regul 2015; 59:53-64. [PMID: 26159297 DOI: 10.1016/j.jbior.2015.05.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 05/25/2015] [Indexed: 06/04/2023]
Abstract
In many human cell types, the class I phosphoinositide 3-kinases play key roles in the control of diverse cellular processes including growth, proliferation, survival and polarity. This is achieved through their activation by many cell surface receptors, leading to the synthesis of the phosphoinositide lipid signal, PIP3, which in turn influences the function of numerous direct PIP3-binding proteins. Here we review PI3K pathway biology and analyse the evolutionary distribution of its components and their functions. The broad phylogenetic distribution of class I PI3Ks in metazoa, amoebozoa and choannoflagellates, implies that these enzymes evolved in single celled organisms and were later co-opted into metazoan intercellular communication. A similar distribution is evident for the AKT and Cytohesin groups of downstream PIP3-binding proteins, with other effectors and pathway components appearing to evolve later. The genomic and functional phylogeny of regulatory systems such as the PI3K pathway provides a framework to improve our understanding of the mechanisms by which key cellular processes are controlled in humans.
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Affiliation(s)
- Nisha Kriplani
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Miguel A Hermida
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Euan R Brown
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Nicholas R Leslie
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK.
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Drosophila Longevity Assurance Conferred by Reduced Insulin Receptor Substrate Chico Partially Requires d4eBP. PLoS One 2015; 10:e0134415. [PMID: 26252766 PMCID: PMC4529185 DOI: 10.1371/journal.pone.0134415] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/08/2015] [Indexed: 12/31/2022] Open
Abstract
Mutations of the insulin/IGF signaling (IIS) pathway extend Drosophila lifespan. Based on genetic epistasis analyses, this longevity assurance is attributed to downstream effects of the FOXO transcription factor. However, as reported FOXO accounts for only a portion of the observed longevity benefit, suggesting there are additional outputs of IIS to mediate aging. One candidate is target of rapamycin complex 1 (TORC1). Reduced TORC1 activity is reported to slow aging, whereas reduced IIS is reported to repress TORC1 activity. The eukaryotic translation initiation factor 4E binding protein (4E-BP) is repressed by TORC1, and activated 4E-BP is reported to increase Drosophila lifespan. Here we use genetic epistasis analyses to test whether longevity assurance mutants of chico, the Drosophila insulin receptor substrate homolog, require Drosophila d4eBP to slow aging. In chico heterozygotes, which are robustly long-lived, d4eBP is required but not sufficient to slow aging. Remarkably, d4eBP is not required or sufficient for chico homozygotes to extend longevity. Likewise, chico heterozygote females partially require d4eBP to preserve age-dependent locomotion, and both chico genotypes require d4eBP to improve stress-resistance. Reproduction and most measures of growth affected by either chico genotype are always independent of d4eBP. In females, chico heterozygotes paradoxically produce more rather than less phosphorylated 4E-BP (p4E-BP). Altered IRS function within the IIS pathway of Drosophila appears to have partial, conditional capacity to regulate aging through an unconventional interaction with 4E-BP.
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Transformation of the intestinal epithelium by the MSI2 RNA-binding protein. Nat Commun 2015; 6:6517. [PMID: 25774828 PMCID: PMC4643281 DOI: 10.1038/ncomms7517] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/30/2015] [Indexed: 01/26/2023] Open
Abstract
The MSI2 RNA binding protein is a potent oncogene playing key roles in hematopoietic stem cell homeostasis and malignant hematopoiesis. Here we demonstrate that MSI2 is expressed in the intestinal stem cell compartment, that its expression is elevated in colorectal adenocarcinomas, and that MSI2 loss of function abrogates colorectal cancer cell growth. MSI2 gain of function in the intestinal epithelium in a drug inducible mouse model is sufficient to phenocopy many of the morphological and molecular consequences of acute loss of the APC tumor suppressor in the intestinal epithelium in a Wnt-independent manner. Transcriptome-wide RNA-binding analysis indicates that MSI2 acts as a pleiotropic inhibitor of known intestinal tumor suppressors including Lrig1, Bmpr1a, Cdkn1a, and Pten. Finally, we demonstrate that inhibition of the PDK-AKT-mTORC1 axis rescues oncogenic consequences of MSI2 induction. Taken together, our findings identify MSI2 as a central component in an unappreciated oncogenic pathway promoting intestinal transformation.
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Slade JD, Staveley BE. Compensatory growth in novel Drosophila Akt1 mutants. BMC Res Notes 2015; 8:77. [PMID: 25889856 PMCID: PMC4372305 DOI: 10.1186/s13104-015-1032-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/24/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Organisms, tissues and cells are genetically programmed to grow to a specific largely pre-set size and shape within the appropriate developmental timing. In the event of mutation, cell death, or tissue damage, the remaining cells may increase their rate of growth to compensate and generate an intact, potentially smaller, tissue or organism in order to achieve the desired size. A delay in the developmental timing could aid in this process. The insulin receptor signalling pathway with its central component, the Akt1 kinase, and endpoint regulator, the transcription factor foxo, plays a significant role in the control of growth. Drosophila melanogaster is an excellent model organism with a well-studied life cycle and a consistently developing compound eye that can undergo analysis to compare changes in the properties of adult ommatidia as an indicator of growth. FINDINGS Imprecise excision of a PZ P-element inserted in the upstream region of Akt1 generated several novel hypomorphic alleles with internally deleted regions of the Pelement. These mutations lead to small, viable Drosophila that present with delays in development. Suppression of this phenotype by the directed expression of Akt1 (+) indicates that the phenotypes observed are Akt1 dependent. Somatic clones of the eyes, consisting of homozygous tissue in otherwise heterozygous organisms that develop within a standard timeframe, signify that more severe phenotypes are masked by an extension in the time of development of homozygous mutants. Generation of Drosophila having the hypomorphic Akt1 alleles and a null allele of the downstream target foxo result in a phenotype very similar to that of the foxo mutant and do not resemble the Akt1 mutants. CONCLUSION The developmental delay of these novel Akt1 hypomorphs results in a latent phenotype uncovered by generation of somatic clones. The compensatory growth occurring during the extended time of development appears to be implemented through alteration of foxo activity. Production of clones is an effective and informative way to observe the effects of mutations that result in small, viable, developmentally delayed flies.
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Affiliation(s)
- Jennifer D Slade
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John's, Newfoundland and Labrador, A1B 3X9, Canada.
| | - Brian E Staveley
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John's, Newfoundland and Labrador, A1B 3X9, Canada.
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Singh AR, Peirce SK, Joshi S, Durden DL. PTEN and PI-3 kinase inhibitors control LPS signaling and the lymphoproliferative response in the CD19+ B cell compartment. Exp Cell Res 2014; 327:78-90. [PMID: 24881819 DOI: 10.1016/j.yexcr.2014.05.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/25/2014] [Accepted: 05/20/2014] [Indexed: 02/07/2023]
Abstract
Pattern recognition receptors (PRRs), e.g. toll receptors (TLRs) that bind ligands within the microbiome have been implicated in the pathogenesis of cancer. LPS is a ligand for two TLR family members, TLR4 and RP105 which mediate LPS signaling in B cell proliferation and migration. Although LPS/TLR/RP105 signaling is well-studied; our understanding of the underlying molecular mechanisms controlling these PRR signaling pathways remains incomplete. Previous studies have demonstrated a role for PTEN/PI-3K signaling in B cell selection and survival, however a role for PTEN/PI-3K in TLR4/RP105/LPS signaling in the B cell compartment has not been reported. Herein, we crossed a CD19cre and PTEN(fl/fl) mouse to generate a conditional PTEN knockout mouse in the CD19+ B cell compartment. These mice were further crossed with an IL-14α transgenic mouse to study the combined effect of PTEN deletion, PI-3K inhibition and expression of IL-14α (a cytokine originally identified as a B cell growth factor) in CD19+ B cell lymphoproliferation and response to LPS stimulation. Targeted deletion of PTEN and directed expression of IL-14α in the CD19+ B cell compartment (IL-14+PTEN-/-) lead to marked splenomegaly and altered spleen morphology at baseline due to expansion of marginal zone B cells, a phenotype that was exaggerated by treatment with the B cell mitogen and TLR4/RP105 ligand, LPS. Moreover, LPS stimulation of CD19+ cells isolated from these mice display increased proliferation, augmented AKT and NFκB activation as well as increased expression of c-myc and cyclinD1. Interestingly, treatment of LPS treated IL-14+PTEN-/- mice with a pan PI-3K inhibitor, SF1126, reduced splenomegaly, cell proliferation, c-myc and cyclin D1 expression in the CD19+ B cell compartment and normalized the splenic histopathologic architecture. These findings provide the direct evidence that PTEN and PI-3K inhibitors control TLR4/RP105/LPS signaling in the CD19+ B cell compartment and that pan PI-3 kinase inhibitors reverse the lymphoproliferative phenotype in vivo.
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Affiliation(s)
- Alok R Singh
- UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093, USA
| | - Susan K Peirce
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Shweta Joshi
- UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093, USA
| | - Donald L Durden
- UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093, USA; Division of Pediatric Hematology-Oncology, UCSD Rady Children׳s Hospital, La Jolla, CA, USA.
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Ying WZ, Aaron KJ, Sanders PW. Sodium and potassium regulate endothelial phospholipase C-γ and Bmx. Am J Physiol Renal Physiol 2014; 307:F58-63. [PMID: 24785188 DOI: 10.1152/ajprenal.00615.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The amount of Na(+) and K(+) in the diet promotes significant changes in endothelial cell function. In the present study, a series of in vitro and in vivo experiments determined the role of Na(+) and K(+) in the regulation of two pleckstrin homology domain-containing intracellular signaling molecules, phospholipase C (PLC)-γ1 and epithelial and endothelial tyrosine kinase/bone marrow tyrosine kinase on chromosome X (Bmx), and agonist-generated Ca(2+) signaling in the endothelium. Extracellular K(+) concentration regulated the levels of activated PLC-γ1, Bmx, and carbachol-stimulated intracellular Ca(2+) mobilization in human endothelial cells. Additional experiments confirmed that high-conductance Ca(2+)-activated K(+) channels and phosphatidylinositol 3-kinase mediated these effects. The content of Na(+) and K(+) in the diet also regulated Bmx levels in endothelial cells and activated PLC-γ1 levels in rats in vivo. The effects of dietary K(+) on Bmx were more pronounced in rats fed a high-salt diet compared with rats fed a low-salt diet. These experiments elucidated an endothelial cell signaling mechanism regulated by electrolytes, further demonstrating an integral relationship between endothelial cell function and dietary Na(+) and K(+) content.
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Affiliation(s)
- Wei-Zhong Ying
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Center for Free Radical Biology, Center for Aging, and Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Kristal J Aaron
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Center for Free Radical Biology, Center for Aging, and Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Paul W Sanders
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Center for Free Radical Biology, Center for Aging, and Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama; and Department of Veterans Affairs Medical Center, Birmingham, Alabama
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Sato-Miyata Y, Muramatsu K, Funakoshi M, Tsuda M, Aigaki T. Overexpression of dilp2 causes nutrient-dependent semi-lethality in Drosophila. Front Physiol 2014; 5:147. [PMID: 24795642 PMCID: PMC3997005 DOI: 10.3389/fphys.2014.00147] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 03/28/2014] [Indexed: 12/14/2022] Open
Abstract
Insulin/insulin-like growth factor (IGF) plays an important role as a systemic regulator of metabolism in multicellular organisms. Hyperinsulinemia, a high level of blood insulin, is often associated with impaired physiological conditions such as hypoglycemia, insulin resistance, and diabetes. However, due to the complex pathophysiology of hyperinsulinemia, the causative role of excess insulin/IGF signaling has remained elusive. To investigate the biological effects of a high level of insulin in metabolic homeostasis and physiology, we generated flies overexpressing Drosophila insulin-like peptide 2 (Dilp2), which has the highest potential of promoting tissue growth among the Ilp genes in Drosophila. In this model, a UAS-Dilp2 transgene was overexpressed under control of sd-Gal4 that drives expression predominantly in developing imaginal wing discs. Overexpression of Dilp2 caused semi-lethality, which was partially suppressed by mutations in the insulin receptor (InR) or Akt1, suggesting that dilp2-induced semi-lethality is mediated by the PI3K/Akt1 signaling. We found that dilp2-overexpressing flies exhibited intensive autophagy in fat body cells. Interestingly, the dilp2-induced autophagy as well as the semi-lethality was partially rescued by increasing the protein content relative to glucose in the media. Our results suggest that excess insulin/IGF signaling impairs the physiology of animals, which can be ameliorated by controlling the nutritional balance between proteins and carbohydrates, at least in flies.
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Affiliation(s)
- Yukiko Sato-Miyata
- Cellular Genetics Laboratory, Department of Biological Sciences, Tokyo Metropolitan University Tokyo, Japan
| | - Keigo Muramatsu
- Cellular Genetics Laboratory, Department of Biological Sciences, Tokyo Metropolitan University Tokyo, Japan
| | - Masabumi Funakoshi
- Cellular Genetics Laboratory, Department of Biological Sciences, Tokyo Metropolitan University Tokyo, Japan
| | - Manabu Tsuda
- Department of Liberal Arts and Human Development, Faculty of Health and Social Services, Kanagawa University of Human Services Yokosuka, Japan
| | - Toshiro Aigaki
- Cellular Genetics Laboratory, Department of Biological Sciences, Tokyo Metropolitan University Tokyo, Japan
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Ma J, Liu J, Wang Z, Gu X, Fan Y, Zhang W, Xu L, Zhang J, Cai D. NF-kappaB-dependent microRNA-425 upregulation promotes gastric cancer cell growth by targeting PTEN upon IL-1β induction. Mol Cancer 2014; 13:40. [PMID: 24571667 PMCID: PMC3941686 DOI: 10.1186/1476-4598-13-40] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 02/20/2014] [Indexed: 01/16/2023] Open
Abstract
Overexpression of the proinflammatory cytokine IL-1β is associated with diverse diseases, including cancer. Alteration of microRNAs has been observed in cancer cells exposed to proinflammatory cytokines, yet their function in inflammation stress remains elusive. Here, we show that IL-1β induces the upregulation of miR-425, which negatively regulates phosphatase and tensin homolog expression by targeting its 3’ UTR. An increase in miR-425 depends on IL-1β-induced NF-kappaB activation, which enhances miR-425 gene transcription upon IL-1β induction. Consequently, repression of phosphatase and tensin homolog by miR-425 promotes gastric cancer cell proliferation, which is required to protect cells from cisplatin-induced apoptosis. Taken together, our data support a critical role for NF-kappaB-dependent upregulation of miR-425, which represents a new pathway for the repression of phosphatase and tensin homolog activation and the promotion of cell survival upon IL-1β induction.
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Affiliation(s)
| | | | | | | | | | | | | | - Jianjun Zhang
- Department of Integrative Medicine, Zhongshan Hospital, Fudan University, Shanghai, PR China.
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Saldanha SN, Tollefsbol TO. Pathway modulations and epigenetic alterations in ovarian tumorbiogenesis. J Cell Physiol 2014; 229:393-406. [PMID: 24105793 DOI: 10.1002/jcp.24466] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 09/06/2013] [Indexed: 12/23/2022]
Abstract
Cellular pathways are numerous and are highly integrated in function in the control of cellular systems. They collectively regulate cell division, proliferation, survival and apoptosis of cells and mutagenesis of key genes that control these pathways can initiate neoplastic transformations. Understanding these pathways is crucial to future therapeutic and preventive strategies of the disease. Ovarian cancers are of three major types; epithelial, germ-cell, and stromal. However, ovarian cancers of epithelial origin, arising from the mesothelium, are the predominant form. Of the subtypes of ovarian cancer, the high-grade serous tumors are fatal, with low survival rate due to late detection and poor response to treatments. Close examination of preserved ovarian tissues and in vitro studies have provided insights into the mechanistic changes occurring in cells mediated by a few key genes. This review will focus on pathways and key genes of the pathways that are mutated or have aberrant functions in the pathology of ovarian cancer. Non-genetic mechanisms that are gaining prominence in the pathology of ovarian cancer, miRNAs and epigenetics, will also be discussed in the review.
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Affiliation(s)
- Sabita N Saldanha
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama; Department of Biological Sciences, Alabama State University, Montgomery, Alabama
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Abstract
As members of the basic helix-loop-helix (bHLH) family of transcription factors, E proteins function in the immune system by directing and maintaining a vast transcriptional network that regulates cell survival, proliferation, differentiation, and function. Proper activity of this network is essential to the functionality of the immune system. Aberrations in E protein expression or function can cause numerous defects, ranging from impaired lymphocyte development and immunodeficiency to aberrant function, cancer, and autoimmunity. Additionally, disruption of inhibitor of DNA-binding (Id) proteins, natural inhibitors of E proteins, can induce additional defects in development and function. Although E proteins have been investigated for several decades, their study continues to yield novel and exciting insights into the workings of the immune system. The goal of this chapter is to discuss the various classical roles of E proteins in lymphocyte development and highlight new and ongoing research into how these roles, if compromised, can lead to disease.
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Affiliation(s)
- Ian Belle
- Department of Immunology, Duke University Medical Center, Durham North Carolina, USA.
| | - Yuan Zhuang
- Department of Immunology, Duke University Medical Center, Durham North Carolina, USA
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Bera A, Ghosh-Choudhury N, Dey N, Das F, Kasinath BS, Abboud HE, Choudhury GG. NFκB-mediated cyclin D1 expression by microRNA-21 influences renal cancer cell proliferation. Cell Signal 2013; 25:2575-86. [PMID: 23981302 PMCID: PMC3896302 DOI: 10.1016/j.cellsig.2013.08.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/23/2013] [Accepted: 08/07/2013] [Indexed: 02/06/2023]
Abstract
MicroRNAs regulate post-transcriptomic landscape in many tumors including renal cell carcinoma. We have recently shown significantly increased expression of miR-21 in renal tumors and that this miRNA contributes to the proliferation of renal cancer cells in culture. However, the mechanism by which miR-21 regulates renal cancer cell proliferation is poorly understood. Addiction to constitutive NFκB activity is hallmark of many cancers including renal cancer. Using miR-21 Sponge in renal cancer cells to block endogenous function of miR-21, we show inhibition of phosphorylation of p65 subunit of NFκB, IKKβ and IκB, which results in attenuation of NFκB transcriptional activity. Subtle reduction in the tumor suppressor PTEN has been linked to various malignancies. We showed previously that miR-21 targeted PTEN in renal cancer cells. Inhibition of PTEN by siRNAs restored miR-21 Sponge-induced suppression of phosphorylation of p65, IKKβ, IκB and NFκB transcriptional activity along with reversal of miR-21 Sponge-reduced phosphorylation of Akt. Expression of constitutively active Akt protected against miR-21 Sponge- and PTEN-mediated decrease in p65/IKKβ/IκB phosphorylation and NFκB transcriptional activity. Furthermore, IKKβ and p65 were required for miR-21-induced renal cancer cell proliferation. Interestingly, miR-21 controlled the expression of cyclin D1 through NFκB-dependent transcription. Finally, we demonstrate that miR-21-regulated renal cancer cell proliferation is mediated by cyclin D1 and CDK4. Together, our results establish a molecular order of a phosphatase-kinase couple involving PTEN/Akt/IKKβ and NFκB-dependent cyclin D1 expression for renal carcinoma cell proliferation by increased miR-21 levels.
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Affiliation(s)
- Amit Bera
- Department of Medicine, University of Texas Health Science Center at San Antonio, Texas
| | - Nandini Ghosh-Choudhury
- Department of Pathology, University of Texas Health Science Center at San Antonio, Texas
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas
| | - Nirmalya Dey
- Department of Medicine, University of Texas Health Science Center at San Antonio, Texas
| | - Falguni Das
- Department of Medicine, University of Texas Health Science Center at San Antonio, Texas
| | - Balakuntalam S. Kasinath
- Department of Medicine, University of Texas Health Science Center at San Antonio, Texas
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas
| | - Hanna E. Abboud
- Department of Medicine, University of Texas Health Science Center at San Antonio, Texas
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas
| | - Goutam Ghosh Choudhury
- Department of Medicine, University of Texas Health Science Center at San Antonio, Texas
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas
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Shakhmantsir I, Massad NL, Kennell JA. Regulation of cuticle pigmentation indrosophilaby the nutrient sensing insulin and TOR signaling pathways. Dev Dyn 2013; 243:393-401. [DOI: 10.1002/dvdy.24080] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/10/2013] [Accepted: 10/10/2013] [Indexed: 11/09/2022] Open
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Wong JJL, Li S, Lim EKH, Wang Y, Wang C, Zhang H, Kirilly D, Wu C, Liou YC, Wang H, Yu F. A Cullin1-based SCF E3 ubiquitin ligase targets the InR/PI3K/TOR pathway to regulate neuronal pruning. PLoS Biol 2013; 11:e1001657. [PMID: 24068890 PMCID: PMC3775723 DOI: 10.1371/journal.pbio.1001657] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 08/08/2013] [Indexed: 11/19/2022] Open
Abstract
Pruning that selectively eliminates unnecessary axons/dendrites is crucial for sculpting the nervous system during development. During Drosophila metamorphosis, dendrite arborization neurons, ddaCs, selectively prune their larval dendrites in response to the steroid hormone ecdysone, whereas mushroom body γ neurons specifically eliminate their axon branches within dorsal and medial lobes. However, it is unknown which E3 ligase directs these two modes of pruning. Here, we identified a conserved SCF E3 ubiquitin ligase that plays a critical role in pruning of both ddaC dendrites and mushroom body γ axons. The SCF E3 ligase consists of four core components Cullin1/Roc1a/SkpA/Slimb and promotes ddaC dendrite pruning downstream of EcR-B1 and Sox14, but independently of Mical. Moreover, we demonstrate that the Cullin1-based E3 ligase facilitates ddaC dendrite pruning primarily through inactivation of the InR/PI3K/TOR pathway. We show that the F-box protein Slimb forms a complex with Akt, an activator of the InR/PI3K/TOR pathway, and promotes Akt ubiquitination. Activation of the InR/PI3K/TOR pathway is sufficient to inhibit ddaC dendrite pruning. Thus, our findings provide a novel link between the E3 ligase and the InR/PI3K/TOR pathway during dendrite pruning.
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Affiliation(s)
- Jack Jing Lin Wong
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
| | - Song Li
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
| | - Edwin Kok Hao Lim
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Yan Wang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Cheng Wang
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
| | - Heng Zhang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Daniel Kirilly
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Chunlai Wu
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Yih-Cherng Liou
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
| | - Hongyan Wang
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Fengwei Yu
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- * E-mail:
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Ying WZ, Aaron KJ, Sanders PW. Transforming growth factor-β regulates endothelial function during high salt intake in rats. Hypertension 2013; 62:951-6. [PMID: 24041947 DOI: 10.1161/hypertensionaha.113.01835] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies have demonstrated that an increase in dietary NaCl (salt) intake stimulated endothelial cells to produce transforming growth factor-β (TGF-β). The intent of the present study was to determine the functional significance of increased TGF-β on endothelial cell function. Young Sprague-Dawley rats were fed diets containing 0.3 or 8.0% NaCl for 2 days before treatment with a specific inhibitor of the TGF-β receptor I/activin receptor-like kinase 5 kinase, or vehicle for another 2 days. At day 4 of study, endothelial phosphorylated Smad2 (S465/467) increased and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) levels decreased in the high-salt-treated rats. In addition, phosphorylated Akt (S473) and phosphorylation of the endothelial isoform of NO synthase (NOS3) at S1177 increased. Treatment with the TGF-β receptor I/activin receptor-like kinase 5 inhibitor reduced Smad2 phosphorylation to levels observed in rats on the low-salt diet and prevented the downstream signaling events induced by the high-salt diet. In human umbilical vein endothelial cells, reduction in PTEN levels increased phosphorylated Akt and NOS3. Treatment of macrovascular endothelial cells with TGF-β1 increased phosphorylated NOS3 and the concentration of NO metabolites in the medium but had no effect on either of these variables in cells pretreated with small interfering RNA directed against PTEN. Thus, during high salt intake, an increase in TGF-β directly promoted a reduction in endothelial PTEN levels, which in turn regulated Akt activation and NOS3 phosphorylation. This effect closes a feedback loop that potentially mitigates the effect of TGF-β on the vasculature.
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Affiliation(s)
- Wei-Zhong Ying
- Division of Nephrology/Department of Medicine, 642 Lyons-Harrison Research Bldg, 1530 Third Ave, South, University of Alabama at Birmingham, Birmingham, AL 35294-0007.
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Fukuzaki Y, Sugawara H, Yamanoha B, Kogure S. 532 nm low-power laser irradiation recovers γ-secretase inhibitor-mediated cell growth suppression and promotes cell proliferation via Akt signaling. PLoS One 2013; 8:e70737. [PMID: 23950991 PMCID: PMC3737144 DOI: 10.1371/journal.pone.0070737] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/27/2013] [Indexed: 02/03/2023] Open
Abstract
Background and Objective The γ-secretase inhibitor (GSI) has been shown to inhibit expression of amyloid beta (Aβ), but GSI also has a side effect of reducing cell survival. Since low-power laser irradiation (LLI) has been known to promote cell survival, we examined whether 532 nm LLI can rescue the GSI side effect or not. Study Design/Materials and Methods The human-derived glioblastoma cells (A-172) were cultured in 35 mm culture dishes or 96-well plate. The center of dish or selected wells was irradiated with 532 nm laser (Nd:YVO4, CW, 60 mW) for 20, 40 and 60 min, respectively. The irradiated cells were photographed at immediately after, 24 and 48 h later and counted. GSI was supplemented in medium 3 h before LLI. The MTT assay was also used to estimate viable cells at 48 h after irradiation. The expression of phosphorylated Akt (p-Akt) or phosphorylated PTEN (p-PTEN) was examined by immunofluorescent staining and measured by fluorescence intensity using the software (BZ-9000, KEYENCE, Japan). Results GSI application depressed cell proliferation as well as cell survival compared to control. GSI down-regulated Aβ but up-regulated p-PTEN and suppressed p-Akt. Application of 532 nm LLI in the presence of GSI significantly recovered the GSI-mediated effects, i.e., LLI could decrease elevated p-PTEN, while increased p-Akt expression with keeping Aβ suppression. The LLI effects had a dose-dependency. Conclusion We confirmed that GSI potently suppressed intracellular Aβ and decreased cell survival. We conclude that a combination of GSI application and 532 nm LLI can increase cell proliferation via Akt activation while keeping PTEN and Aβ suppressed.
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Affiliation(s)
- Yumi Fukuzaki
- Department of Bioinformatics, Graduate School of Engineering, Soka University, Hachioji, Tokyo, Japan
| | - Haruna Sugawara
- Department of Bioinformatics, Graduate School of Engineering, Soka University, Hachioji, Tokyo, Japan
| | - Banri Yamanoha
- Department of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, Japan
| | - Shinichi Kogure
- Department of Bioinformatics, Graduate School of Engineering, Soka University, Hachioji, Tokyo, Japan
- * E-mail:
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Abstract
This article presents an overview of the PI3K/Akt/mTOR signaling pathway. As a central regulator of cell growth, protein translation, survival, and metabolism, activation of this signaling pathway contributes to the pathogenesis of many tumor types. Biochemical and genetic aberrations of this pathway observed in various cancer types are explored. Last, pathway inhibitors both in development and already approved by the Food and Drug Administration are discussed.
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PDK1 controls upstream PI3K expression and PIP3 generation. Oncogene 2013; 33:3043-53. [PMID: 23893244 DOI: 10.1038/onc.2013.266] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 04/30/2013] [Accepted: 05/20/2013] [Indexed: 12/17/2022]
Abstract
The PI3K/PDK1/Akt signaling axis is centrally involved in cellular homeostasis and controls cell growth and proliferation. Due to its key function as regulator of cell survival and metabolism, the dysregulation of this pathway is manifested in several human pathologies including cancers and immunological diseases. Thus, current therapeutic strategies target the components of this signaling cascade. In recent years, numerous feedback loops have been identified that attenuate PI3K/PDK1/Akt-dependent signaling. Here, we report the identification of an additional level of feedback regulation that depends on the negative transcriptional control of phosphatidylinositol 3-kinase (PI3K) class IA subunits. Genetic deletion of 3-phosphoinositide-dependent protein kinase 1 (PDK1) or the pharmacological inhibition of its downstream effectors, that is, Akt and mammalian target of rapamycin (mTOR), relieves this suppression and leads to the upregulation of PI3K subunits, resulting in enhanced generation of phosphatidylinositol-3,4,5-trisphosphate (PIP3). Apparently, this transcriptional induction is mediated by the concerted action of different transcription factor families, including the transcription factors cAMP-responsive element-binding protein and forkhead box O. Collectively, we propose that PDK1 functions as a cellular sensor that balances basal PIP3 generation at levels sufficient for survival but below a threshold being harmful to the cell. Our study suggests that the efficiency of therapies targeting the aberrantly activated PI3K/PDK1/Akt pathway might be increased by the parallel blockade of feedback circuits.
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Platelet-derived growth factor/vascular endothelial growth factor receptor inactivation by sunitinib results in Tsc1/Tsc2-dependent inhibition of TORC1. Mol Cell Biol 2013; 33:3762-79. [PMID: 23878397 DOI: 10.1128/mcb.01570-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptors are implicated in development and tumorigenesis and dual inhibitors like sunitinib are prescribed for cancer treatment. While mammalian VEGF and PDGF receptors are present in multiple isoforms and heterodimers, Drosophila encodes one ancestral PDGF/VEGF receptor, PVR. We identified PVR in an unbiased cell-based RNA interference (RNAi) screen of all Drosophila kinases and phosphatases for novel regulators of TORC1. PVR is essential to sustain target of rapamycin complex 1 (TORC1) and extracellular signal-regulated kinase (ERK) activity in cultured insect cells and for maximal stimulation by insulin. CG32406 (henceforth, PVRAP, for PVR adaptor protein), an Src homology 2 (SH2) domain-containing protein, binds PVR and is required for TORC1 activation. TORC1 activation by PVR involves Tsc1/Tsc2 and, in a cell-type-dependent manner, Lobe (ortholog of PRAS40). PVR is required for cell survival in vitro, and both PVR and TORC1 are necessary for hemocyte expansion in vivo. Constitutive PVR activation induces tumor-like structures that exhibit high TORC1 activity. Like its mammalian orthologs, PVR is inhibited by sunitinib, and sunitinib treatment phenocopies PVR loss in hemocytes. Sunitinib inhibits TORC1 in insect cells, and sunitinib-mediated TORC1 inhibition requires an intact Tsc1/Tsc2 complex. Sunitinib similarly inhibited TORC1 in human endothelial cells in a Tsc1/Tsc2-dependent manner. Our findings provide insight into the mechanism of action of PVR and may have implications for understanding sunitinib sensitivity and resistance in tumors.
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