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Schulman ES, Nishi H, Pelleg A. Degranulation of human mast cells: modulation by P2 receptors' agonists. Front Immunol 2023; 14:1216580. [PMID: 37868982 PMCID: PMC10585249 DOI: 10.3389/fimmu.2023.1216580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/04/2023] [Indexed: 10/24/2023] Open
Abstract
Since the late 1970s, there has been an alarming increase in the incidence of asthma and its morbidity and mortality. Acute obstruction and inflammation of allergic asthmatic airways are frequently caused by inhalation of exogenous substances such as allergens cross-linking IgE receptors expressed on the surface of the human lung mast cells (HLMC). The degree of constriction of human airways produced by identical amounts of inhaled allergens may vary from day to day and even hour to hour. Endogenous factors in the human mast cell (HMC)'s microenvironment during allergen exposure may markedly modulate the degranulation response. An increase in allergic responsiveness may significantly enhance bronchoconstriction and breathlessness. This review focuses on the role that the ubiquitous endogenous purine nucleotide, extracellular adenosine 5'-triphosphate (ATP), which is a component of the damage-associated molecular patterns, plays in mast cells' physiology. ATP activates P2 purinergic cell-surface receptors (P2R) to trigger signaling cascades resulting in heightened inflammatory responses. ATP is the most potent enhancer of IgE-mediated HLMC degranulation described to date. Current knowledge of ATP as it relates to targeted receptor(s) on HMC along with most recent studies exploring HMC post-receptor activation pathways are discussed. In addition, the reviewed studies may explain why brief, minimal exposures to allergens (e.g., dust, cat, mouse, and grass) can unpredictably lead to intense clinical reactions. Furthermore, potential therapeutic approaches targeting ATP-related enhancement of allergic reactions are presented.
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Affiliation(s)
- Edward S. Schulman
- Division of Pulmonary, Critical Care and Allergy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Haruhisa Nishi
- Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan
| | - Amir Pelleg
- Danmir Therapeutics, LLC, Haverford, PA, United States
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Ye X, Chen L, Wang H, Peng S, Liu M, Yao L, Zhang Y, Shi YS, Cao Y, Yang JJ, Chen G. Genetic inhibition of PDK1 robustly reduces plaque deposition and ameliorates gliosis in the 5×FAD mouse model of Alzheimer's disease. Neuropathol Appl Neurobiol 2022; 48:e12839. [PMID: 35881686 DOI: 10.1111/nan.12839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 05/05/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022]
Abstract
AIMS Abundant recent evidence has shown that 3-phosphoinositide-dependent protein kinase 1 (PDK1) is activated in Alzheimer's disease (AD). However, it remains unknown whether inhibition of PDK1 in neurons may affect AD-like pathology in animal models of AD. Here, we aim to examine the effects of specific inactivation of neuronal PDK1 on pathology and behaviour in 5×FAD mice and to identify the underlying molecular mechanisms. METHODS The Cre-loxP system was employed to generate Pdk1 cKO/5×FAD mice, in which PDK1 is inactivated in excitatory neurons in the adult forebrain. Cellular and behavioural techniques were used to examine plaque burden, inflammatory responses and spatial working memory in mice. Biochemical and molecular analyses were conducted to investigate relevant mechanisms. RESULTS First, Aβ deposition was massively decreased and gliosis was highly attenuated in Pdk1 cKO/5×FAD mice compared with 5×FAD mice. Second, memory deficits were significantly improved in Pdk1 cKO/5×FAD mice. Third, APP levels were notably decreased in Pdk1 cKO/5×FAD mice. Fourth, mammalian target of rapamycin (mTOR) signalling and ribosome biogenesis were reduced in Pdk1 cKO/5×FAD mice. CONCLUSIONS Neuron-specific deletion of PDK1 robustly ameliorates AD-like pathology and improves spatial working memory in 5×FAD mice. We propose that genetic approach to inhibit PDK1 may be an effective strategy to slow AD.
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Affiliation(s)
- Xiaolian Ye
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Lu Chen
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - He Wang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Shixiao Peng
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Mengjia Liu
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Liyang Yao
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Yizhi Zhang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Yun Stone Shi
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Ying Cao
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Jian-Jun Yang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Guiquan Chen
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
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Nishi H, Niyonsaba F, Pelleg A, Schulman ES. Enhancement of Mast Cell Degranulation Mediated by Purinergic Receptors' Activation and PI3K Type δ. THE JOURNAL OF IMMUNOLOGY 2021; 207:1001-1008. [PMID: 34330752 DOI: 10.4049/jimmunol.2001002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 05/28/2021] [Indexed: 11/19/2022]
Abstract
Mast cells express multiple metabotropic purinergic P2Y receptor (P2YR) subtypes. Few studies have evaluated their role in human mast cell (HMC) allergic response as quantified by degranulation induced by cross-linking the high-affinity IgE receptor (FcεRI). We have previously shown that extracellular nucleotides modify the FcεRI activation-dependent degranulation in HMCs derived from human lungs, but the mechanism of this action has not been fully delineated. This study was undertaken to determine the mechanism of activation of P2YRs on the degranulation of HMCs and elucidate the specific postreceptor pathways involved. Sensitized LAD2 cells, a human-derived mast cell line, were subjected to a weak allergic stimulation (WAS) using a low concentration of Ag in the absence and presence of P2YR agonists. Only the metabotropic purinergic P2Y11 receptor (P2Y11R) agonist, adenosine 5'-(3-thio)triphosphate (ATPγS), enhanced WAS-induced degranulation resulting in a net 7-fold increase in release (n = 4; p < 0.01). None of the P2YR agonists tested, including high concentrations of ATPγS (1000 μM), enhanced WAS-induced intracellular Ca2+ mobilization, an essential component of activated FcεRI-induced degranulation. Both a PI3K inhibitor and the relevant gene knockout decreased the ATPγS-induced enhancement. The effect of ATPγS was associated with enhanced phosphorylation of PI3K type δ and protein kinase B, but not the phosphoinositide-dependent kinase-1. The effects of ATPγS were dose dependently inhibited by NF157, a P2Y11R antagonist. To our knowledge, these data indicate for the first time that P2YR is linked to enhancement of allergic degranulation in HMC via the PI3K/protein kinase B pathway.
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Affiliation(s)
- Haruhisa Nishi
- Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan;
| | - François Niyonsaba
- Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Faculty of International Liberal Arts, Juntendo University, Tokyo, Japan
| | - Amir Pelleg
- Danmir Therapeutics, LLC, Haverford, PA; and
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Colardo M, Segatto M, Di Bartolomeo S. Targeting RTK-PI3K-mTOR Axis in Gliomas: An Update. Int J Mol Sci 2021; 22:4899. [PMID: 34063168 PMCID: PMC8124221 DOI: 10.3390/ijms22094899] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/01/2021] [Accepted: 05/03/2021] [Indexed: 12/13/2022] Open
Abstract
Gliomas are the most common and challenging malignancies of the central nervous system (CNS), due to their infiltrative nature, tendency to recurrence, and poor response to treatments. Indeed, despite the advances in neurosurgical techniques and in radiation therapy, the modest effects of therapy are still challenging. Moreover, tumor recurrence is associated with the onset of therapy resistance; it is therefore critical to identify effective and well-tolerated pharmacological approaches capable of inducing durable responses in the appropriate patient groups. Molecular alterations of the RTK/PI3K/Akt/mTOR signaling pathway are typical hallmarks of glioma, and several clinical trials targeting one or more players of this axis have been launched, showing disappointing results so far, due to the scarce BBB permeability of certain compounds or to the occurrence of resistance/tolerance mechanisms. However, as RTK/PI3K/mTOR is one of the pivotal pathways regulating cell growth and survival in cancer biology, targeting still remains a strong rationale for developing strategies against gliomas. Future rigorous clinical studies, aimed at addressing the tumor heterogeneity, the interaction with the microenvironment, as well as diverse posology adjustments, are needed-which might unravel the therapeutic efficacy and response prediction of an RTK/PI3K/mTOR-based approach.
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Affiliation(s)
| | | | - Sabrina Di Bartolomeo
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, IS, Italy; (M.C.); (M.S.)
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Wang H, Liu M, Zou G, Wang L, Duan W, He X, Ji M, Zou X, Hu Y, Yang J, Chen G. Deletion of PDK1 in oligodendrocyte lineage cells causes white matter abnormality and myelination defect in the central nervous system. Neurobiol Dis 2020; 148:105212. [PMID: 33276084 DOI: 10.1016/j.nbd.2020.105212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/17/2020] [Accepted: 11/29/2020] [Indexed: 12/01/2022] Open
Abstract
PDK1 (3-Phosphoinositide dependent protein kinase-1) is a member in the PI3K (phosphatidylinositol 3 kinase) pathway and is implicated in neurodevelopmental disease with microcephaly. Although the role of PDK1 in neurogenesis has been broadly studied, it remains unknown how PDK1 may regulate oligogenesis in the central nervous system (CNS). To address this question, we generated oligodendrocyte (OL) lineage cells specific PDK1 conditional knockout (cKO) mice. We find that PDK1 cKOs display abnormal white matter (WM), massive loss of mature OLs and severe defect in myelination in the CNS. In contrast, these mutants exhibit normal neuronal development and unchanged apoptosis in the CNS. We demonstrate that deletion of PDK1 severely impairs OL differentiation. We show that genetic or pharmacological inhibition of PDK1 causes deficit in the mammalian target of rapamycin (mTor) signaling and down-regulation of Sox10. Together, these results highlight a critical role of PDK1 in OL differentiation during postnatal CNS development.
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Affiliation(s)
- He Wang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, No. 1 East Jianshe Road, Zhengzhou 450052, China
| | - Mengjia Liu
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Avenue, Nanjing, Jiangsu Province 210061, China
| | - Gang Zou
- Department of Anesthesiology, The Second Affiliated Hospital, Nanjing Medical University, 121 Jiangjiayuan Avenue, Nanjing, Jiangsu Province 210003, China
| | - Long Wang
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Avenue, Nanjing, Jiangsu Province 210061, China
| | - Wenbin Duan
- Department of General Surgery, The Second Clinical Medical College, Shenzhen People's Hospital, Jinan University, Shenzhen 518000, China
| | - Xue He
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, No. 1 East Jianshe Road, Zhengzhou 450052, China
| | - Muhuo Ji
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, No. 1 East Jianshe Road, Zhengzhou 450052, China
| | - Xiaochuan Zou
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Avenue, Nanjing, Jiangsu Province 210061, China
| | - Yimin Hu
- Department of General Surgery, The Second Clinical Medical College, Shenzhen People's Hospital, Jinan University, Shenzhen 518000, China.
| | - Jianjun Yang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, No. 1 East Jianshe Road, Zhengzhou 450052, China.
| | - Guiquan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Avenue, Nanjing, Jiangsu Province 210061, China.
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Bai D, Wu Y, Deol P, Nobumori Y, Zhou Q, Sladek FM, Liu X. Palmitic acid negatively regulates tumor suppressor PTEN through T366 phosphorylation and protein degradation. Cancer Lett 2020; 496:127-133. [PMID: 33039560 DOI: 10.1016/j.canlet.2020.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/19/2020] [Accepted: 10/06/2020] [Indexed: 01/22/2023]
Abstract
Chronic elevated free fatty (FFA) levels are linked to metabolic disorders and tumorigenesis. However, the molecular mechanism by which FFAs induce cancer remains poorly understood. Here, we show that the tumor suppressor PTEN protein levels were decreased in high fat diet (HFD) fed mice. As palmitic acid (PA, C16:0) showed a significant increase in the HFD fed mice, we further investigated its role in PTEN down regulation. Our studies revealed that exposure of cells to high doses of PA induced mTOR/S6K-mediated phosphorylation of PTEN at T366. The phosphorylation subsequently enhanced the interaction of PTEN with the E3 ubiquitin ligase WW domain-containing protein 2 (WWP2), which promoted polyubiquitination of PTEN and protein degradation. Consistent with PTEN degradation, exposure of cells to increased concentrations of PA also promoted PTEN-mediated AKT activation and cell proliferation. Significantly, a higher level of S6K activation, PTEN T366 phosphorylation, and AKT activation were also observed in the livers of the HFD fed mice. These results provide a molecular mechanism by which a HFD and elevated PA regulate cell proliferation through inactivation of tumor suppressor PTEN.
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Affiliation(s)
- Dongmei Bai
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA
| | - Yong Wu
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA
| | - Poonamjot Deol
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Yumiko Nobumori
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA
| | - Qi Zhou
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA
| | - Frances M Sladek
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Xuan Liu
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA.
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PDK1 Regulates the Maintenance of Cell Body and the Development of Dendrites of Purkinje Cells by pS6 and PKCγ. J Neurosci 2020; 40:5531-5548. [PMID: 32487697 DOI: 10.1523/jneurosci.2496-19.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 01/09/2023] Open
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) plays a critical role in the development of mammalian brain. Here, we investigated the role of PDK1 in Purkinje cells (PCs) by generating the PDK1-conditional knock-out mice (cKO) through crossing PV-cre or Pcp2-cre mice with Pdk1fl/fl mice. The male mice were used in the behavioral testing, and the other experiments were performed on mice of both sexes. These PDK1-cKO mice displayed decreased cerebellar size and impaired motor balance and coordination. By the electrophysiological recording, we observed the reduced spontaneous firing of PCs from the cerebellar slices of the PDK1-cKO mice. Moreover, the cell body size of PCs in the PDK1-cKO mice was time dependently reduced compared with that in the control mice. And the morphologic complexity of PCs was also decreased after PDK1 deletion. These effects may have contributed to the reduction of the rpS6 (reduced ribosomal protein S6) phosphorylation and the PKCγ expression in PDK1-cKO mice since the upregulation of pS6 by treatment of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-1, the agonist of mTOR1, partly rescued the reduction in the cell body size of the PCs, and the delivery of recombinant adeno-associated virus-PKCγ through cerebellar injection rescued the reduced complexity of the dendritic arbor in PDK1-cKO mice. Together, our data suggest that PDK1, by regulating rpS6 phosphorylation and PKCγ expression, controls the cell body maintenance and the dendritic development in PCs and is critical for cerebellar motor coordination.SIGNIFICANCE STATEMENT Here, we show the role of 3-phosphoinositide-dependent protein kinase-1 (PDK1) in Purkinje cells (PCs). The ablation of PDK1 in PCs resulted in a reduction of cell body size, and dendritic complexity and abnormal spontaneous firing, which attributes to the motor defects in PDK1-conditional knock-out (cKO) mice. Moreover, the ribosomal protein S6 (rpS6) phosphorylation and the expression of PKCγ are downregulated after the ablation of PDK1. Additionally, upregulation of rpS6 phosphorylation by3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-1 partly rescued the reduction in cell body size of PCs, and the overexpression of PKCγ in PDK1-KO PCs rescued the reduction in the dendritic complexity. These findings indicate that PDK1 contributes to the maintenance of the cell body and the dendritic development of PCs by regulating rpS6 phosphorylation and PKCγ expression.
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Waking up quiescent neural stem cells: Molecular mechanisms and implications in neurodevelopmental disorders. PLoS Genet 2020; 16:e1008653. [PMID: 32324743 PMCID: PMC7179833 DOI: 10.1371/journal.pgen.1008653] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neural stem cells (NSCs) are crucial for development, regeneration, and repair of the nervous system. Most NSCs in mammalian adult brains are quiescent, but in response to extrinsic stimuli, they can exit from quiescence and become reactivated to give rise to new neurons. The delicate balance between NSC quiescence and activation is important for adult neurogenesis and NSC maintenance. However, how NSCs transit between quiescence and activation remains largely elusive. Here, we discuss our current understanding of the molecular mechanisms underlying the reactivation of quiescent NSCs. We review recent advances on signaling pathways originated from the NSC niche and their crosstalk in regulating NSC reactivation. We also highlight new intrinsic paradigms that control NSC reactivation in Drosophila and mammalian systems. We also discuss emerging evidence on modeling human neurodevelopmental disorders using NSCs.
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Fu Y, Dong J, Wang J, You M, Wei L, Fu H, Wang Y, Chen J. Developmental Exposure to Di-(2-ethylhexyl) Phthalate Induces Cerebellar Granule Cell Apoptosis via the PI3K/AKT Signaling Pathway. Exp Neurobiol 2018; 27:472-488. [PMID: 30636900 PMCID: PMC6318557 DOI: 10.5607/en.2018.27.6.472] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/26/2022] Open
Abstract
Di-(2-ethylhexyl) phthalate (DEHP) is an ubiquitous environmental contaminant because of its extensive use in plastics and its persistence. As an environmental endocrine disruptor, it is suspected to interfere with neurodevelopment in people. However, evidence of the effects of maternal DEHP exposure on cerebellar development in offspring is scarce. The objective of this study was to investigate maternal exposure to DEHP and its effect on apoptosis of cerebellar granule cells (CGCs) and related mechanisms. Pregnant Wistar rats were administrated DEHP (0, 30, 300 and 750 mg/kg/d) by gavage from gestational day (GD) 0 to postnatal day (PN) 21. Primary CGCs were also exposed to mono-(2-ethylhexyl) phthalate (MEHP), the main metabolite of DEHP, for 24 h with concentrations of 0, 25, 100 and 250 µM. The CGCs of male offspring from 300 and 750 mg/kg/d DEHP exposure groups showed significantly increased apoptosis. In addition, the PI3K/AKT signaling pathway was inhibited in the male offspring of the 300 and 750 mg/kg/d DEHP exposure groups. However, effects on female pups were not obvious. Apoptosis was also elevated and the PI3K/AKT signaling pathway was inhibited after primary CGCs were exposed to MEHP. Furthermore, apoptosis was reduced after treatment with the PI3K/AKT signaling pathway activator, insulin-like growth factor (IGF) 1, and increased after treatment with LY294002, an inhibitor of the PI3K/AKT signaling pathway. These results suggested that maternal DEHP exposure induced apoptosis in the CGCs of male pups via the PI3K/AKT signaling pathway, and the apoptosis could be rescued by IGF1 and aggravated by LY294002.
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Affiliation(s)
- Yuanyuan Fu
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Jianan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Mingdan You
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Lingling Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Hui Fu
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang 110122, China
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Guvenek A, Tian B. Analysis of alternative cleavage and polyadenylation in mature and differentiating neurons using RNA-seq data. QUANTITATIVE BIOLOGY 2018; 6:253-266. [PMID: 31380142 DOI: 10.1007/s40484-018-0148-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background Most eukaryotic protein-coding genes exhibit alternative cleavage and polyadenylation (APA), resulting in mRNA isoforms with different 3' untranslated regions (3' UTRs). Studies have shown that brain cells tend to express long 3' UTR isoforms using distal cleavage and polyadenylation sites (PASs). Methods Using our recently developed, comprehensive PAS database PolyA_DB, we developed an efficient method to examine APA, named Significance Analysis of Alternative Polyadenylation using RNA-seq (SAAP-RS). We applied this method to study APA in brain cells and neurogenesis. Results We found that neurons globally express longer 3' UTRs than other cell types in brain, and microglia and endothelial cells express substantially shorter 3' UTRs. We show that the 3' UTR diversity across brain cells can be corroborated with single cell sequencing data. Further analysis of APA regulation of 3' UTRs during differentiation of embryonic stem cells into neurons indicates that a large fraction of the APA events regulated in neurogenesis are similarly modulated in myogenesis, but to a much greater extent. Conclusion Together, our data delineate APA profiles in different brain cells and indicate that APA regulation in neurogenesis is largely an augmented process taking place in other types of cell differentiation.
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Affiliation(s)
- Aysegul Guvenek
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ 07103, USA.,Rutgers School of Graduate Studies, Newark, NJ 07103, USA
| | - Bin Tian
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ 07103, USA.,Rutgers Cancer Institute of New Jersey, Newark, NJ 07103, USA.,Rutgers Brain Health Institute, Newark, NJ 07103, USA
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Xu M, Han X, Liu R, Li Y, Qi C, Yang Z, Zhao C, Gao J. PDK1 Deficit Impairs the Development of the Dentate Gyrus in Mice. Cereb Cortex 2018; 29:1185-1198. [DOI: 10.1093/cercor/bhy024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Indexed: 12/22/2022] Open
Affiliation(s)
- Min Xu
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| | - Xiaoning Han
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Histology and Embryology, School of Medicine, Southeast University, Nanjing, China
| | - Rui Liu
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| | - Yanjun Li
- Model Animal Research Center of Nanjing University and MOE Key Laboratory of Model Animals for Disease Study, Nanjing, China
| | - Cui Qi
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| | - Zhongzhou Yang
- Model Animal Research Center of Nanjing University and MOE Key Laboratory of Model Animals for Disease Study, Nanjing, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Histology and Embryology, School of Medicine, Southeast University, Nanjing, China
- Center of Depression, Beijing Institute for Brain Disorders, Beijing, China
| | - Jun Gao
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
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Gagliardi PA, Puliafito A, Primo L. PDK1: At the crossroad of cancer signaling pathways. Semin Cancer Biol 2018; 48:27-35. [DOI: 10.1016/j.semcancer.2017.04.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/28/2017] [Accepted: 04/26/2017] [Indexed: 12/28/2022]
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Xu C, Yu L, Hou J, Jackson RJ, Wang H, Huang C, Liu T, Wang Q, Zou X, Morris RG, Spires-Jones TL, Yang Z, Yin Z, Xu Y, Chen G. Conditional Deletion of PDK1 in the Forebrain Causes Neuron Loss and Increased Apoptosis during Cortical Development. Front Cell Neurosci 2017; 11:330. [PMID: 29104535 PMCID: PMC5655024 DOI: 10.3389/fncel.2017.00330] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/05/2017] [Indexed: 12/26/2022] Open
Abstract
Decreased expression but increased activity of PDK1 has been observed in neurodegenerative disease. To study in vivo function of PDK1 in neuron survival during cortical development, we generate forebrain-specific PDK1 conditional knockout (cKO) mice. We demonstrate that PDK1 cKO mice display striking neuron loss and increased apoptosis. We report that PDK1 cKO mice exhibit deficits on several behavioral tasks. Moreover, PDK1 cKO mice show decreased activities for Akt and mTOR. These results highlight an essential role of endogenous PDK1 in the maintenance of neuronal survival during cortical development.
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Affiliation(s)
- Congyu Xu
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Linjie Yu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Jinxing Hou
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Rosemary J Jackson
- Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh, United Kingdom
| | - He Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Chaoli Huang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Tingting Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Qihui Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Xiaochuan Zou
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Richard G Morris
- Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh, United Kingdom.,Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Instituto de Neurociencias, Alicante, Spain
| | - Tara L Spires-Jones
- Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Dementia Prevention, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Zhongzhou Yang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Zhenyu Yin
- Department of Geriatrics, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Guiquan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
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14
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Játiva P, Ceña V. Use of nanoparticles for glioblastoma treatment: a new approach. Nanomedicine (Lond) 2017; 12:2533-2554. [DOI: 10.2217/nnm-2017-0223] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Glioblastoma (GBM) is a very aggressive CNS tumor with poor prognosis. Current treatment lacks efficacy indicating that new therapeutic approaches are needed. One of these new approaches is based on the use of nanoparticles (NPs) to deliver different cargos (antitumoral drugs or genetic materials) to tumoral cells. This review covers the signaling pathways altered in GBM cells to understand the rationale behind choosing new therapeutic targets and recent advances in the use of different NPs to deliver to GBM cells, both in vitro and in vivo, different therapeutic molecules. A special focus is placed on the effect of NPs on orthotopic brain tumors since this animal model represents the optimal model for translational purposes.
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Affiliation(s)
- Pablo Játiva
- Unidad Asociada Neurodeath, Universidad de Castilla-La Mancha, Albacete, Spain
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain
| | - Valentín Ceña
- Unidad Asociada Neurodeath, Universidad de Castilla-La Mancha, Albacete, Spain
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain
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15
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Mutation of the 3-Phosphoinositide-Dependent Protein Kinase 1 (PDK1) Substrate-Docking Site in the Developing Brain Causes Microcephaly with Abnormal Brain Morphogenesis Independently of Akt, Leading to Impaired Cognition and Disruptive Behaviors. Mol Cell Biol 2016; 36:2967-2982. [PMID: 27644329 DOI: 10.1128/mcb.00230-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/13/2016] [Accepted: 09/15/2016] [Indexed: 11/20/2022] Open
Abstract
The phosphoinositide (PI) 3-kinase/Akt signaling pathway plays essential roles during neuronal development. 3-Phosphoinositide-dependent protein kinase 1 (PDK1) coordinates the PI 3-kinase signals by activating 23 kinases of the AGC family, including Akt. Phosphorylation of a conserved docking site in the substrate is a requisite for PDK1 to recognize, phosphorylate, and activate most of these kinases, with the exception of Akt. We exploited this differential mechanism of regulation by generating neuron-specific conditional knock-in mice expressing a mutant form of PDK1, L155E, in which the substrate-docking site binding motif, termed the PIF pocket, was disrupted. As a consequence, activation of all the PDK1 substrates tested except Akt was abolished. The mice exhibited microcephaly, altered cortical layering, and reduced circuitry, leading to cognitive deficits and exacerbated disruptive behavior combined with diminished motivation. The abnormal patterning of the adult brain arises from the reduced ability of the embryonic neurons to polarize and extend their axons, highlighting the essential roles that the PDK1 signaling beyond Akt plays in mediating the neuronal responses that regulate brain development.
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16
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Olbrich P, Lorenz M, Cura Daball P, Lucena JM, Rensing-Ehl A, Sanchez B, Führer M, Camacho-Lovillo M, Melon M, Schwarz K, Neth O, Speckmann C. Activated PI3Kδ syndrome type 2: Two patients, a novel mutation, and review of the literature. Pediatr Allergy Immunol 2016; 27:640-4. [PMID: 27116393 DOI: 10.1111/pai.12585] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/24/2016] [Indexed: 02/04/2023]
Abstract
BACKGROUND Autosomal dominant gain-of-function mutations in PIK3R1 encoding for the regulatory subunit (p85α, p55α, and p50α) of Class IA phosphoinositide 3-kinase (PI3K) result in the activated PI3Kδ syndrome (APDS) type 2 characterized by childhood-onset combined immunodeficiency, lymphoproliferation, and immune dysregulation. To improve clinical awareness and understanding of these rare diseases, we reviewed all hitherto published cases with APDS type 1 and type 2 for their clinical and immunologic symptoms and added novel clinical, immunologic, and genetic findings of two patients with APDS type 2. METHODS Clinical, immunologic, and genetic evaluation of two new patients with APDS2 was performed followed by the systematic collection of all available previously published data of patients with APDS1 and APDS2. RESULTS Patients with APDS type 1 (n = 49) and type 2 (n = 15) showed an indistinguishable immunologic phenotype. Overlapping clinical features shared by APDS type 1 and type 2 were observed, but our review also revealed previously unnoticed clinical differences such as remarkably high incidence of microcephaly, poor growth/short stature in patients with APDS2. Clinical management and outcome were variable and included prophylactic antibiotics, immunosuppression, immunoglobulin substitution, and hematopoietic stem cell transplantation. CONCLUSIONS A disease-specific registry collecting prospective and long-term follow-up data of patients with APDS, as currently set up by the European Society for Immunodeficiencies, are needed to better understand the natural history and to optimize treatment concepts and thereby improving the outcome of this heterogenous patient group.
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Affiliation(s)
- Peter Olbrich
- Seccion de Infectología e Inmunopatología, Unidad de Pediatria, Hospital Virgen del Rocío, Sevilla/Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain
| | - Myriam Lorenz
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Paola Cura Daball
- Center for Chronic Immunodeficiency (CCI), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - José Manuel Lucena
- Unidad de Inmunología, Hospital Universitario Virgen del Rocío, Sevilla, Spain
| | - Anne Rensing-Ehl
- Center for Chronic Immunodeficiency (CCI), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Berta Sanchez
- Unidad de Inmunología, Hospital Universitario Virgen del Rocío, Sevilla, Spain
| | - Marita Führer
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Marisol Camacho-Lovillo
- Seccion de Infectología e Inmunopatología, Unidad de Pediatria, Hospital Virgen del Rocío, Sevilla/Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain
| | - Marta Melon
- Seccion de Infectología e Inmunopatología, Unidad de Pediatria, Hospital Virgen del Rocío, Sevilla/Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain
| | - Klaus Schwarz
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service, Baden-Württemberg-Hessen, Ulm, Germany
| | - Olaf Neth
- Seccion de Infectología e Inmunopatología, Unidad de Pediatria, Hospital Virgen del Rocío, Sevilla/Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain
| | - Carsten Speckmann
- Center for Chronic Immunodeficiency (CCI), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.,Center for Pediatrics, Department of Pediatric Hematology and Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
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17
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Rapamycin prevents, but does not reverse, aberrant migration in Pten knockout neurons. Neurobiol Dis 2016; 93:12-20. [PMID: 26992888 DOI: 10.1016/j.nbd.2016.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 02/08/2016] [Accepted: 03/10/2016] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Phosphatase and tensin homolog (PTEN) is a major negative regulator of the Akt/mammalian target of rapamycin (MTOR) pathway. Mutations in PTEN have been found in a subset of individuals with autism and macrocephaly. Further, focal cortical dysplasia (FCD) has been observed in patients with PTEN mutations prompting us to examine the role of Pten in neuronal migration. The dentate gyrus of Pten(Flox/Flox) mice was injected with Cre- and non-Cre-expressing retroviral particles, which integrate into the dividing genome to birthdate cells. Control and Pten knockout (KO) cell position in the granule cell layer was quantified over time to reveal that Pten KO neurons exhibit an aberrant migratory phenotype beginning at 7.5days-post retroviral injection (DPI). We then assessed whether rapamycin, a mTor inhibitor, could prevent or reverse aberrant migration of granule cells. The preventative group received daily intraperitoneal (IP) injections of rapamycin from 3 to 14 DPI, before discrepancies in cell position have been established, while the reversal group received rapamycin afterward, from 14 to 24 DPI. We found that rapamycin prevented and reversed somal hypertrophy. However, rapamycin prevented, but did not reverse aberrant migration in Pten KO cells. We also find that altered migration occurs through mTorC1 and not mTorC2 activity. Together, these findings suggest a temporal window by which rapamycin can treat aberrant migration, and may have implications for the use of rapamycin to treat PTEN-mutation associated disorders. SIGNIFICANCE STATEMENT Mutations in phosphatase and tensin homolog (PTEN) have been linked to a subset of individuals with autism and macrocephaly, as well as Cowden Syndrome and focal cortical dysplasia. Pten loss leads to neuronal hypertrophy, but the role of Pten in neuronal migration is unclear. Here we have shown that loss of Pten leads to aberrant migration, which can be prevented but not reversed by treatment with rapamycin, a mTor inhibitor. These results are important to consider as clinical trials are developed to examine rapamycin as a therapeutic for autism with PTEN mutations. Our findings show that some abnormalities cannot be reversed, and suggest the potential need for genetic screening and preventative treatment.
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18
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Schrötter S, Leondaritis G, Eickholt BJ. Capillary Isoelectric Focusing of Akt Isoforms Identifies Highly Dynamic Phosphorylation in Neuronal Cells and Brain Tissue. J Biol Chem 2016; 291:10239-51. [PMID: 26945062 PMCID: PMC4858973 DOI: 10.1074/jbc.m115.700138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Indexed: 02/03/2023] Open
Abstract
The PI3K/PTEN/Akt pathway has been established as a core signaling pathway that is crucial for the integration of neurons into neuronal circuits and the maintenance of the architecture and function of neurons in the adult brain. Akt1–3 kinases are specifically activated by two phosphorylation events on residues Thr308 and Ser473 upon growth factor signaling, which subsequently phosphorylate a vast cohort of downstream targets. However, we still lack a clear understanding of the complexity and regulation of isoform specificity within the PI3K/PTEN/Akt pathway. We utilized a capillary-based isoelectric focusing method to study dynamics of Akt phosphorylation in neuronal cells and the developing brain and identify previously undescribed features of Akt phosphorylation and activation. First, we show that the accumulation of multiple phosphorylation events on Akt forms occur concurrently with Ser473 and Thr308 phosphorylation upon acute PI3K activation and provide evidence for uncoupling of Ser473 and Thr308 phosphorylation, as well as differential sensitivities of Akt1 forms upon PI3K inhibition. Second, we detect a transient shift in Akt isoform phosphorylation and activation pattern during early postnatal brain development, at stages corresponding to synapse development and maturation. Third, we show differential sensitivities of Ser473-Akt species to PTEN deletion in mature neurons, which suggests inherent differences in the Akt pools that are accessible to growth factors as compared with the pools that are controlled by PTEN. Our study demonstrates the presence of complex phosphorylation events of Akt in a time- and signal-dependent manner in neurons.
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Affiliation(s)
- Sandra Schrötter
- From the Charité-Universitätsmedizin Berlin, Cluster of Excellence NeuroCure and Institute of Biochemistry, Berlin 10117, Germany
| | - George Leondaritis
- From the Charité-Universitätsmedizin Berlin, Cluster of Excellence NeuroCure and Institute of Biochemistry, Berlin 10117, Germany
| | - Britta J Eickholt
- From the Charité-Universitätsmedizin Berlin, Cluster of Excellence NeuroCure and Institute of Biochemistry, Berlin 10117, Germany
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19
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Abstract
The central nervous system is comprised of multiple cell types including neurons, glia, and other supporting cells that may differ dramatically in levels of signaling pathway activation. Immunohistochemistry in conjunction with drug interference are powerful tools that allow evaluation of signaling pathways in different cell types of the mouse central nervous system in vivo. Here we provide detailed protocols for immunohistochemistry to evaluate three essential components in the PI3K pathway in mouse brain: Pten, p-Akt, and p-4ebp1, and for rapamycin treatment to modulate mTOR signaling in vivo.
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Affiliation(s)
- Guo Zhu
- Department of Pathology, University of Tennessee Health Sciences Center, Memphis, TN, 38163, USA
| | - Suzanne J Baker
- Department of Developmental Neurobiology, St Jude Children's Research Hospital, Room D2006C, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA.
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20
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Yin P, Xu J, He S, Liu F, Yin J, Wan C, mei C, Yin Y, Xu X, Xia Z. Endoplasmic Reticulum Stress in Heat- and Shake-Induced Injury in the Rat Small Intestine. PLoS One 2015; 10:e0143922. [PMID: 26636675 PMCID: PMC4670120 DOI: 10.1371/journal.pone.0143922] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 11/11/2015] [Indexed: 12/12/2022] Open
Abstract
We investigated the mechanisms underlying damage to rat small intestine in heat- and shake-induced stress. Eighteen Sprague-Dawley rats were randomly divided into a control group and a 3-day stressed group treated 2 h daily for 3 days on a rotary platform at 35°C and 60 r/min. Hematoxylin and eosin-stained paraffin sections of the jejunum following stress revealed shedding of the villus tip epithelial cells and lamina propria exposure. Apoptosis increased at the villus tip and extended to the basement membrane. Photomicrographs revealed that the microvilli were shorter and sparser; the nuclear envelope invaginated and gaps in the karyolemma increased; and the endoplasmic reticulum (ER) swelled significantly. Gene microarray analysis assessed 93 differentially expressed genes associated with apoptosis, ER stress, and autophagy. Relevant genes were compiled from the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Forty-one genes were involved in the regulation of apoptosis, fifteen were related to autophagy, and eleven responded to ER stress. According to KEGG, the apoptosis pathways, mitogen-activated protein kinase(MAPK) signaling pathway, the mammalian target of rapamycin (mTOR) signaling pathway, and regulation of autophagy were involved. Caspase3 (Casp3), caspase12 (Casp12), and microtubule-associate proteins 1 light chain 3(LC3) increased significantly at the villus tip while mTOR decreased; phosphorylated-AKT (P-AKT) decreased. ER stress was involved and induced autophagy and apoptosis in rat intestinal damage following heat and shake stress. Bioinformatic analysis will help determine the underlying mechanisms in stress-induced damage in the small intestine.
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Affiliation(s)
- Peng Yin
- CAU-BUA TCVM Teaching and Researching Team, College of Veterinary Medicine, China Agricultural University (CAU), Beijing, PR China
| | - Jianqin Xu
- CAU-BUA TCVM Teaching and Researching Team, College of Veterinary Medicine, China Agricultural University (CAU), Beijing, PR China
| | - Shasha He
- CAU-BUA TCVM Teaching and Researching Team, College of Veterinary Medicine, China Agricultural University (CAU), Beijing, PR China
| | - Fenghua Liu
- College of Animal Science and Technology, Beijing University of Agriculture (BUA), Beijing, PR China
- * E-mail: (ZX); (YY); (FL)
| | - Jie Yin
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China
| | - Changrong Wan
- CAU-BUA TCVM Teaching and Researching Team, College of Veterinary Medicine, China Agricultural University (CAU), Beijing, PR China
| | - Chen mei
- College of Animal Science and Technology, Beijing University of Agriculture (BUA), Beijing, PR China
| | - Yulong Yin
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China
- * E-mail: (ZX); (YY); (FL)
| | - Xiaolong Xu
- CAU-BUA TCVM Teaching and Researching Team, College of Veterinary Medicine, China Agricultural University (CAU), Beijing, PR China
| | - Zhaofei Xia
- CAU-BUA TCVM Teaching and Researching Team, College of Veterinary Medicine, China Agricultural University (CAU), Beijing, PR China
- * E-mail: (ZX); (YY); (FL)
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21
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Russo AJ. Decreased Phosphorylated Protein Kinase B (Akt) in Individuals with Autism Associated with High Epidermal Growth Factor Receptor (EGFR) and Low Gamma-Aminobutyric Acid (GABA). Biomark Insights 2015; 10:89-94. [PMID: 26508828 PMCID: PMC4607071 DOI: 10.4137/bmi.s21946] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/03/2015] [Accepted: 09/08/2015] [Indexed: 11/05/2022] Open
Abstract
Dysregulation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway could contribute to the pathogenesis of autism spectrum disorders. In this study, phosphorylated Akt concentration was measured in 37 autistic children and 12, gender and age similar neurotypical, controls using an enzyme-linked immunosorbent assay. Akt levels were compared to biomarkers known to be associated with epidermal growth factor receptor (EGFR) and c-Met (hepatocyte growth factor (HGF) receptor) pathways and severity levels of 19 autism-related symptoms. We found phosphorylated Akt levels significantly lower in autistic children and low Akt levels correlated with high EGFR and HGF and low gamma-aminobutyric acid, but not other biomarkers. Low Akt levels also correlated significantly with increased severity of receptive language, conversational language, hypotonia, rocking and pacing, and stimming, These results suggest a relationship between decreased phosphorylated Akt and selected symptom severity in autistic children and support the suggestion that the AKT pathways may be associated with the etiology of autism.
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Affiliation(s)
- Anthony J Russo
- Department of Biology, Hartwick College, Oneonta, NY, USA. ; Pfeiffer Medical Center, Health Research Institute, Warrenville, IL, USA
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22
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Chimaphilin inhibits proliferation and induces apoptosis in multidrug resistant osteosarcoma cell lines through insulin-like growth factor-I receptor (IGF-IR) signaling. Chem Biol Interact 2015; 237:25-30. [DOI: 10.1016/j.cbi.2015.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/26/2015] [Accepted: 05/11/2015] [Indexed: 11/24/2022]
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23
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Differential SKIP expression in PTEN-deficient glioblastoma regulates cellular proliferation and migration. Oncogene 2014; 34:3711-27. [DOI: 10.1038/onc.2014.303] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 07/18/2014] [Accepted: 08/13/2014] [Indexed: 12/25/2022]
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24
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Chiappini F, Catalano KJ, Lee J, Peroni OD, Lynch J, Dhaneshwar AS, Wellenstein K, Sontheimer A, Neel BG, Kahn BB. Ventromedial hypothalamus-specific Ptpn1 deletion exacerbates diet-induced obesity in female mice. J Clin Invest 2014; 124:3781-92. [PMID: 25083988 DOI: 10.1172/jci68585] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 06/19/2014] [Indexed: 01/05/2023] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) regulates food intake (FI) and energy expenditure (EE) by inhibiting leptin signaling in the hypothalamus. In peripheral tissues, PTP1B regulates insulin signaling, but its effects on CNS insulin action are largely unknown. Mice harboring a whole-brain deletion of the gene encoding PTP1B (Ptpn1) are lean, leptin-hypersensitive, and resistant to high fat diet-induced (HFD-induced) obesity. Arcuate proopiomelanocortin (POMC) neuron-specific deletion of Ptpn1 causes a similar, but much milder, phenotype, suggesting that PTP1B also acts in other neurons to regulate metabolism. Steroidogenic factor-1-expressing (SF-1-expressing) neurons in the ventromedial hypothalamus (VMH) play an important role in regulating body weight, FI, and EE. Surprisingly, Ptpn1 deletion in SF-1 neurons caused an age-dependent increase in adiposity in HFD-fed female mice. Although leptin sensitivity was increased and FI was reduced in these mice, they had impaired sympathetic output and decreased EE. Immunohistochemical analysis showed enhanced leptin and insulin signaling in VMH neurons from mice lacking PTP1B in SF-1 neurons. Thus, in the VMH, leptin negatively regulates FI, promoting weight loss, whereas insulin suppresses EE, leading to weight gain. Our results establish a novel role for PTP1B in regulating insulin action in the VMH and suggest that increased insulin responsiveness in SF-1 neurons can overcome leptin hypersensitivity and enhance adiposity.
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25
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Patel M, Gomez NC, McFadden AW, Moats-Staats BM, Wu S, Rojas A, Sapp T, Simon JM, Smith SV, Kaiser-Rogers K, Davis IJ. PTEN deficiency mediates a reciprocal response to IGFI and mTOR inhibition. Mol Cancer Res 2014; 12:1610-20. [PMID: 24994750 DOI: 10.1158/1541-7786.mcr-14-0006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
UNLABELLED Recent evidence implicates the insulin-like growth factor (IGF) pathway in development of Ewing sarcoma, a highly malignant bone and soft-tissue tumor that primarily affects children and young adults. Despite promising results from preclinical studies of therapies that target this pathway, early-phase clinical trials have shown that a significant fraction of patients do not benefit, suggesting that cellular factors determine tumor sensitivity. Using FAIRE-seq, a chromosomal deletion of the PTEN locus in a Ewing sarcoma cell line was identified. In primary tumors, PTEN deficiency was observed in a large subset of cases, although not mediated by large chromosomal deletions. PTEN loss resulted in hyperactivation of the AKT signaling pathway. PTEN rescue led to decreased proliferation, inhibition of colony formation, and increased apoptosis. Strikingly, PTEN loss decreased sensitivity to IGF1R inhibitors but increased responsiveness to temsirolimus, a potent mTOR inhibitor, as marked by induction of autophagy. These results suggest that PTEN is lost in a significant fraction of primary tumors, and this deficiency may have therapeutic consequences by concurrently attenuating responsiveness to IGF1R inhibition while increasing activity of mTOR inhibitors. The identification of PTEN status in the tumors of patients with recurrent disease could help guide the selection of therapies. IMPLICATIONS PTEN status in Ewing sarcoma affects cellular responses to IGFI and mTOR-directed therapy, thus justifying its consideration as a biomarker in future clinical trials.
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Affiliation(s)
- Mukund Patel
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nicholas C Gomez
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Andrew W McFadden
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Billie M Moats-Staats
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Sam Wu
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Andres Rojas
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Travis Sapp
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jeremy M Simon
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Scott V Smith
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kathleen Kaiser-Rogers
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Ian J Davis
- Department of Genetics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
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26
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Veleva-Rotse BO, Barnes AP. Brain patterning perturbations following PTEN loss. Front Mol Neurosci 2014; 7:35. [PMID: 24860420 PMCID: PMC4030135 DOI: 10.3389/fnmol.2014.00035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/15/2014] [Indexed: 12/23/2022] Open
Abstract
This review will consider the impact of compromised PTEN signaling in brain patterning. We approach understanding the contribution of PTEN to nervous system development by surveying the findings from the numerous genetic loss-of-function models that have been generated as well as other forms of PTEN inactivation. By exploring the developmental programs influenced by this central transduction molecule, we can begin to understand the molecular mechanisms that shape the developing brain. A wealth of data indicates that PTEN plays critical roles in a variety of stages during brain development. Many of them are considered here including: stem cell proliferation, fate determination, polarity, migration, process outgrowth, myelination and somatic hypertrophy. In many of these contexts, it is clear that PTEN phosphatase activity contributes to the observed effects of genetic deletion or depletion, however recent studies have also ascribed non-catalytic functions to PTEN in regulating cell function. We also explore the potential impact this alternative pool of PTEN may have on the developing brain. Together, these elements begin to form a clearer picture of how PTEN contributes to the emergence of brain structure and binds form and function in the nervous system.
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Affiliation(s)
- Biliana O Veleva-Rotse
- Neuroscience Graduate Program, Oregon Health and Science University Portland, OR, USA ; Department of Pediatrics, Oregon Health and Science University Portland, OR, USA
| | - Anthony P Barnes
- Neuroscience Graduate Program, Oregon Health and Science University Portland, OR, USA ; Department of Pediatrics, Oregon Health and Science University Portland, OR, USA ; Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
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Dysregulation of the IGF-I/PI3K/AKT/mTOR signaling pathway in autism spectrum disorders. Int J Dev Neurosci 2014; 35:35-41. [PMID: 24662006 DOI: 10.1016/j.ijdevneu.2014.03.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/13/2014] [Accepted: 03/13/2014] [Indexed: 11/20/2022] Open
Abstract
The IGF-I/PI3K/AKT/mTOR signaling pathway plays an important role in the regulation of cell growth, proliferation, differentiation, motility, survival, metabolism and protein synthesis. Insulin-like growth factor-I (IGF-I) is synthesized in the liver and fibroblasts, and its biological actions are mediated by the IGF-I receptor (IGF-IR). The binding of IGF-I to IGF-IR leads to the activation of phosphatidylinositol 3-kinase (PI3K). Activated PI3K stimulates the production of phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] and phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3]. The PH domain of AKT (protein kinase B, PKB) (v-AKT murine thymoma viral oncogene homolog) binds to PI(4,5)P2 and PI(3,4,5)P3, followed by phosphorylation of the Thr308 and Ser473 regulatory sites. Tuberous sclerosis complex 1 (TSC1) and TSC2 are upstream regulators of mammalian target of rapamycin (mTOR) and downstream effectors of the PI3K/AKT signaling pathway. The activation of AKT suppresses the TSC1/TSC2 heterodimer, which is an upstream regulator of mTOR. Dysregulated IGF-I/PI3K/AKT/mTOR signaling has been shown to be associated with autism spectrum disorders (ASDs). In this review, we discuss the emerging evidence for a functional relationship between the IGF-I/PI3K/AKT/mTOR pathway and ASDs, as well as a possible role of this signaling pathway in the diagnosis and treatment of ASDs.
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Yin A, Qiu Y, Jia B, Song T, Yu Y, Alberts I, Zhong M. The developmental pattern of the RAS/RAF/Erk1/2 pathway in the BTBR autism mouse model. Int J Dev Neurosci 2014; 39:2-8. [PMID: 24631207 DOI: 10.1016/j.ijdevneu.2014.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 01/22/2014] [Accepted: 01/22/2014] [Indexed: 12/01/2022] Open
Abstract
BTBR mice exhibit several autistic-like behaviors and are currently used as a model for understanding mechanisms that may be responsible for the pathogenesis of autism. Ras/Raf/ERK1/2 signaling has been suggested to play an important role in neural development, learning, memory, and cognition. Two studies reported that a deletion of a locus on chromosome 16 containing the mitogen-activated protein kinase 3 (MAPK3) gene, which encodes ERK1, is associated with autism. In the present study, Ras/Raf/ERK1/2 signaling was found to be up-regulated in BTBR mice relative to matched control B6 mice, to further suggest involvement in the pathogenesis of autism. To further characterize the developmental pattern of Ras/Raf/ERK1/2 signaling, varying stages during development were sampled to reveal an up-regulation in newborn and 2-week old BTBR mice relative to age-matched B6 mice. By the age of 3-week, Ras/Raf/ERK1/2 signaling in the brain of BTBR mice was unaltered relative to B6 mice, with this trend maintained in 6-week samples. These results suggest that the alteration of Ras/Raf/ERK signaling in the early developmental stages in mice could contribute to the noted autistic phenotype. Furthermore, these findings support the value of BTBR mice to serve as a human analog for autistic etiological research and aid in a better understanding of the developmental mechanisms of autism.
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Affiliation(s)
- Ailan Yin
- Department of Obstetrics & Gynecology, Nanfang Hospital, Guangzhou, China; Southern Medical University, Guangzhou, China
| | - Yuwen Qiu
- Department of Obstetrics & Gynecology, Nanfang Hospital, Guangzhou, China
| | - Bei Jia
- Department of Obstetrics & Gynecology, Nanfang Hospital, Guangzhou, China
| | - Tianrong Song
- Department of Obstetrics & Gynecology, Nanfang Hospital, Guangzhou, China
| | - Yanhong Yu
- Southern Medical University, Guangzhou, China
| | - Ian Alberts
- Department of Natural Sciences, LarGuardia CC, CUNY, NY, NY 11101, USA
| | - Mei Zhong
- Department of Obstetrics & Gynecology, Nanfang Hospital, Guangzhou, China.
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29
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Dangelmaier C, Manne BK, Liverani E, Jin J, Bray P, Kunapuli SP. PDK1 selectively phosphorylates Thr(308) on Akt and contributes to human platelet functional responses. Thromb Haemost 2013; 111:508-17. [PMID: 24352480 DOI: 10.1160/th13-06-0484] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 11/14/2013] [Indexed: 11/05/2022]
Abstract
3-phosphoinositide-dependent protein kinase 1 (PDK1), a member of the protein A,G and C (AGC) family of proteins, is a Ser/Thr protein kinase that can phosphorylate and activate other protein kinases from the AGC family, including Akt at Thr308, all of which play important roles in mediating cellular responses. The functional role of PDK1 or the importance of phosphorylation of Akt on Thr308 for its activity has not been investigated in human platelets. In this study, we tested two pharmacological inhibitors of PDK1, BX795 and BX912, to assess the role of Thr308 phosphorylation on Akt. PAR4-induced phosphorylation of Akt on Thr308 was inhibited by BX795 without affecting phosphorylation of Akt on Ser473. The lack of Thr308 phosphorylation on Akt also led to the inhibition of PAR4-induced phosphorylation of two downstream substrates of Akt, viz. GSK3β and PRAS40. In vitro kinase activity of Akt was completely abolished if Thr308 on Akt was not phosphorylated. BX795 caused inhibition of 2-MeSADP-induced or collagen-induced aggregation, ATP secretion and thromboxane generation. Primary aggregation induced by 2-MeSADP was also inhibited in the presence of BX795. PDK1 inhibition also resulted in reduced clot retraction indicating its role in outside-in signalling. These results demonstrate that PDK1 selectively phosphorylates Thr308 on Akt thereby regulating its activity and plays a positive regulatory role in platelet physiological responses.
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Affiliation(s)
| | | | | | | | | | - S P Kunapuli
- Satya P. Kunapuli, PhD, Department of Physiology, Temple University, Rm. 217 MRB, 3420 N. Broad Street, Philadelphia, Pennsylvania 19140, USA, Tel.: +1 215 707 4615, Fax: +1 215 707 4003, E-mail:
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30
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Hunt CP, Fabb SA, Pouton CW, Haynes JM. DNA-dependent protein kinase is a context dependent regulator of Lmx1a and midbrain specification. PLoS One 2013; 8:e78759. [PMID: 24194952 PMCID: PMC3806860 DOI: 10.1371/journal.pone.0078759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 09/18/2013] [Indexed: 11/30/2022] Open
Abstract
The identification of small molecules capable of directing pluripotent cell differentiation towards specific lineages is highly desirable to both reduce cost, and increase efficiency. Within neural progenitors, LIM homeobox transcription factor 1 alpha (Lmx1a) is required for proper development of roof plate and cortical hem structures of the forebrain, as well as the development of floor plate and midbrain dopaminergic neurons. In this study we generated homologous recombinant cell lines expressing either luciferase or β-lactamase under the control of the Lmx1a promoter, and used these cell lines to investigate kinase-mediated regulation of Lmx1a activity during neuronal differentiation. A screen of 143 small molecule tyrosine kinase inhibitors yielded 16 compounds that positively or negatively modulated Lmx1a activity. Inhibition of EGF, VEGF and DNA-dependent protein kinase (DNA-PK) signaling significantly upregulated Lmx1a activity whereas MEK inhibition strongly downregulated its activity. Quantitative FACS analysis revealed that the DNA-PK inhibitor significantly increased the number of Lmx1a+ progenitors while subsequent qPCR showed an upregulation of Notch effectors, the basic helix-loop-helix genes, Hes5 and Hey1. FACS further revealed that DNA-PK-mediated regulation of Lmx1a+ cells is dependent on the rapamycin-sensitive complex, mTORC1. Interestingly, this DNA-PK inhibitor effect was preserved in a co-culture differentiation protocol. Terminal differentiation assays showed that DNA-PK inhibition shifted development of neurons from forebrain toward midbrain character as assessed by Pitx3/TH immunolabeling and corresponding upregulation of midbrain (En1), but not forebrain (FoxG1) transcripts. These studies show that Lmx1a signaling in mouse embryonic stem cells contributes to a molecular cascade establishing neuronal specification. The data presented here identifies a novel regulatory pathway where signaling from DNA-PK appears to suppress midbrain-specific Lmx1a expression.
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Affiliation(s)
- Cameron P. Hunt
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville), Melbourne, Australia
| | - Stewart A. Fabb
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville), Melbourne, Australia
| | - Colin W. Pouton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville), Melbourne, Australia
- * E-mail: (JMH); (CWP)
| | - John M. Haynes
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville), Melbourne, Australia
- * E-mail: (JMH); (CWP)
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31
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Coordinate regulation of mature dopaminergic axon morphology by macroautophagy and the PTEN signaling pathway. PLoS Genet 2013; 9:e1003845. [PMID: 24098148 PMCID: PMC3789823 DOI: 10.1371/journal.pgen.1003845] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 08/14/2013] [Indexed: 12/11/2022] Open
Abstract
Macroautophagy is a conserved mechanism for the bulk degradation of proteins and organelles. Pathological studies have implicated defective macroautophagy in neurodegeneration, but physiological functions of macroautophagy in adult neurons remain unclear. Here we show that Atg7, an essential macroautophagy component, regulates dopaminergic axon terminal morphology. Mature Atg7-deficient midbrain dopamine (DA) neurons harbored selectively enlarged axonal terminals. This contrasted with the phenotype of DA neurons deficient in Pten - a key negative regulator of the mTOR kinase signaling pathway and neuron size - that displayed enlarged soma but unaltered axon terminals. Surprisingly, concomitant deficiency of both Atg7 and Pten led to a dramatic enhancement of axon terminal enlargement relative to Atg7 deletion alone. Similar genetic interactions between Atg7 and Pten were observed in the context of DA turnover and DA-dependent locomotor behaviors. These data suggest a model for morphological regulation of mature dopaminergic axon terminals whereby the impact of mTOR pathway is suppressed by macroautophagy.
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32
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Liu X, Cheng C, Shao B, Wu X, Ji Y, Lu X, Shen A. LPS-Stimulating Astrocyte-Conditioned Medium Causes Neuronal Apoptosis Via Increasing CDK11p58 Expression in PC12 Cells Through Downregulating AKT Pathway. Cell Mol Neurobiol 2013; 33:779-87. [DOI: 10.1007/s10571-013-9945-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 05/08/2013] [Indexed: 01/03/2023]
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Lee JT, Shan J, Zhong J, Li M, Zhou B, Zhou A, Parsons R, Gu W. RFP-mediated ubiquitination of PTEN modulates its effect on AKT activation. Cell Res 2013; 23:552-64. [PMID: 23419514 DOI: 10.1038/cr.2013.27] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The PTEN tumor suppressor is a lipid phosphatase that has a central role in regulating the phosphatidylinositol-3-kinase (PI3K) signal transduction cascade. Nevertheless, the mechanism by which the PTEN activity is regulated in cells needs further elucidation. Although previous studies have shown that ubiquitination of PTEN can modulate its stability and subcellular localization, the role of ubiquitination in the most critical aspect of PTEN function, its phosphatase activity, has not been fully addressed. Here, we identify a novel E3 ubiquitin ligase of PTEN, Ret finger protein (RFP), that is able to promote atypical polyubiquitinations of PTEN. These ubiquitinations do not lead to PTEN instability or relocalization, but rather significantly inhibit PTEN phosphatase activity and therefore modulate its ability to regulate the PI3K signal transduction cascade. Indeed, RFP overexpression relieves PTEN-mediated inhibitory effects on AKT activation; in contrast, RNAi-mediated knockdown of endogenous RFP enhances the ability of PTEN to suppress AKT activation. Moreover, RFP-mediated ubiquitination of PTEN inhibits PTEN-dependent activation of TRAIL expression and also suppresses its ability to induce apoptosis. Our findings demonstrate a crucial role of RFP-mediated ubiquitination in controlling PTEN activity.
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Affiliation(s)
- James T Lee
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 1130 St Nicholas Avenue, New York, NY 10032, USA
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34
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Bartesaghi S, Salomoni P. Tumor suppressive pathways in the control of neurogenesis. Cell Mol Life Sci 2013; 70:581-97. [PMID: 22802124 PMCID: PMC11113109 DOI: 10.1007/s00018-012-1063-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/16/2012] [Accepted: 06/18/2012] [Indexed: 12/16/2022]
Abstract
The generation of specialized neural cells in the developing and postnatal central nervous system is a highly regulated process, whereby neural stem cells divide to generate committed neuronal progenitors, which then withdraw from the cell cycle and start to differentiate. Cell cycle checkpoints play a major role in regulating the balance between neural stem cell expansion and differentiation. Loss of tumor suppressors involved in checkpoint control can lead to dramatic alterations of neurogenesis, thus contributing to neoplastic transformation. Here we summarize and critically discuss the existing literature on the role of tumor suppressive pathways and their regulatory networks in the control of neurogenesis and transformation.
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Affiliation(s)
- Stefano Bartesaghi
- Samantha Dickson Brain Cancer Unit, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6DD UK
| | - Paolo Salomoni
- Samantha Dickson Brain Cancer Unit, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6DD UK
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35
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Sabarinathan D, Vanisree AJ. Plausible role of naringenin against cerebrally implanted C6 glioma cells in rats. Mol Cell Biochem 2012; 375:171-8. [PMID: 23263903 DOI: 10.1007/s11010-012-1539-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 11/23/2012] [Indexed: 11/27/2022]
Abstract
Gliomas encompass a significant percentage of intrinsic neoplasms of the central nervous system in both adults and children. The constitutive activation of phosphatidylinositol 3-kinase (PI3K) and protein kinase B is the hallmark of glioma. The up-regulated protein kinase B could influence the expression of cyclooxygenase-2, an indicator of aggressive glioma. The present study was embarked to demonstrate the effect of naringenin (50 mg/kg bw for 30 days administrated orally) on PI3K, protein kinase B, and cyclooxygenase-2 in cerebrally implanted rat C6 glioma model. After the experimental period of 30 days, the animals were sacrificed and excised brain tissues were subjected to study the expressions of PI3K, protein kinase B, and cyclooxygenase-2 by reverse transcriptase polymerase chain reaction followed Western blot analysis. The activity of COX-2 (production of prostaglandin-E(2)) was also determined by high pressure liquid chromatography. The results showed that the naringenin could down-regulate the expressions of PI3K and protein kinase B along with activity and expression of cyclooxygenase-2 in C6 glioma cells implanted rat brain. In conclusion, it can be argued that the reduced expressions of phosphatidylinositol 3-kinase and protein kinase B in naringenin-treated glioma-induced rat brain might be involved in the down-regulation of cyclooxygenase-2 expression and activity. Thus, fine-tuned investigation of which will be helpful for targeted drug discovery against glioma.
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Affiliation(s)
- Devan Sabarinathan
- Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600 025, Tamilnadu, India.
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36
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Perrin AJ, Gunda M, Yu B, Yen K, Ito S, Forster S, Tissenbaum HA, Derry WB. Noncanonical control of C. elegans germline apoptosis by the insulin/IGF-1 and Ras/MAPK signaling pathways. Cell Death Differ 2012; 20:97-107. [PMID: 22935616 DOI: 10.1038/cdd.2012.101] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The insulin/IGF-1 pathway controls a number of physiological processes in the nematode worm Caenorhabditis elegans, including development, aging and stress response. We previously found that the Akt/PKB ortholog AKT-1 dampens the apoptotic response to genotoxic stress in the germline by negatively regulating the p53-like transcription factor CEP-1. Here, we report unexpected rearrangements to the insulin/IGF-1 pathway, whereby the insulin-like receptor DAF-2 and 3-phosphoinositide-dependent protein kinase PDK-1 oppose AKT-1 to promote DNA damage-induced apoptosis. While DNA damage does not affect phosphorylation at the PDK-1 site Thr350/Thr308 of AKT-1, it increased phosphorylation at Ser517/Ser473. Although ablation of daf-2 or pdk-1 completely suppressed akt-1-dependent apoptosis, the transcriptional activation of CEP-1 was unaffected, suggesting that daf-2 and pdk-1 act independently or downstream of cep-1 and akt-1. Ablation of the akt-1 paralog akt-2 or the downstream target of the insulin/IGF-1 pathway daf-16 (a FOXO transcription factor) restored sensitivity to damage-induced apoptosis in daf-2 and pdk-1 mutants. In addition, daf-2 and pdk-1 mutants have reduced levels of phospho-MPK-1/ERK in their germ cells, indicating that the insulin/IGF-1 pathway promotes Ras signaling in the germline. Ablation of the Ras effector gla-3, a negative regulator of mpk-1, restored sensitivity to apoptosis in daf-2 mutants, suggesting that gla-3 acts downstream of daf-2. In addition, the hypersensitivity of let-60/Ras gain-of-function mutants to damage-induced apoptosis was suppressed to wild-type levels by ablation of daf-2. Thus, insulin/IGF-1 signaling selectively engages AKT-2/DAF-16 to promote DNA damage-induced germ cell apoptosis downstream of CEP-1 through the Ras pathway.
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Affiliation(s)
- A J Perrin
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
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37
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Jeon SJ, Han SH, Yang SI, Choi JW, Kwon KJ, Park SH, Kim HY, Cheong JH, Ryu JH, Ko KH, Wells DG, Shin CY. Positive feedback regulation of Akt-FMRP pathway protects neurons from cell death. J Neurochem 2012; 123:226-38. [DOI: 10.1111/j.1471-4159.2012.07886.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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38
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Ro SH, Liu D, Yeo H, Paik JH. FoxOs in neural stem cell fate decision. Arch Biochem Biophys 2012; 534:55-63. [PMID: 22902436 DOI: 10.1016/j.abb.2012.07.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 02/07/2023]
Abstract
Neural stem cells (NSCs) persist over the lifespan of mammals to give rise to committed progenitors and their differentiated cells in order to maintain the brain homeostasis. To this end, NSCs must be able to self-renew and otherwise maintain their quiescence. Suppression of aberrant proliferation or undesired differentiation is crucial to preclude either malignant growth or precocious depletion of NSCs. The PI3K-Akt-FoxO signaling pathway plays a central role in the regulation of multiple stem cells including one in the mammalian brain. In particular, members of FoxO family transcription factors are highly expressed in these stem cells. As an important downstream effector of growth, differentiation, and stress stimuli, mammalian FoxO transcription factor family controls cellular proliferation, oxidative stress response, homeostasis, and eventual maintenance of long-term repopulating potential. The review will focus on the current understanding of FoxO function in NSCs as well as discuss their biological activities that contribute to determining neural stem cell fate.
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Affiliation(s)
- Seung-Hyun Ro
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
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39
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Blair PJ, Harvey J. PTEN: a new player controlling structural and functional synaptic plasticity. J Physiol 2012; 590:1017. [PMID: 22399818 DOI: 10.1113/jphysiol.2012.227868] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Peter J Blair
- Department ofPhysiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
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40
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Anton K, Baehring JM, Mayer T. Glioblastoma multiforme: overview of current treatment and future perspectives. Hematol Oncol Clin North Am 2012; 26:825-53. [PMID: 22794286 DOI: 10.1016/j.hoc.2012.04.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Glioblastoma multiforme is the most common primary malignant tumor of the central nervous system. Despite new insights into glioblastoma pathophysiology, the prognosis for patients diagnosed with this highly aggressive tumor remains bleak. Current treatment regimens combine surgical resection and chemoradiotherapy, providing an increase in median overall survival from 12.1 to 14.6 months. Ongoing preclinical and clinical studies evaluating the efficacy of novel therapies provide hope for increasing survival benefit. This article reviews the advancements in glioblastoma treatment in newly diagnosed and recurrent glioblastoma, including novel therapies such as antiangiogenic agents, mammalian target of rapamycin inhibitors, poly(ADP-ribose) polymerase-1 inhibitors, and immunotherapies.
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Affiliation(s)
- Kevin Anton
- Department of Pharmacology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ 08903, USA
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41
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Diez H, Garrido JJ, Wandosell F. Specific roles of Akt iso forms in apoptosis and axon growth regulation in neurons. PLoS One 2012; 7:e32715. [PMID: 22509246 PMCID: PMC3324480 DOI: 10.1371/journal.pone.0032715] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 01/30/2012] [Indexed: 01/31/2023] Open
Abstract
Akt is a member of the AGC kinase family and consists of three isoforms. As one of the major regulators of the class I PI3 kinase pathway, it has a key role in the control of cell metabolism, growth, and survival. Although it has been extensively studied in the nervous system, we have only a faint knowledge of the specific role of each isoform in differentiated neurons. Here, we have used both cortical and hippocampal neuronal cultures to analyse their function. We characterized the expression and function of Akt isoforms, and some of their substrates along different stages of neuronal development using a specific shRNA approach to elucidate the involvement of each isoform in neuron viability, axon development, and cell signalling. Our results suggest that three Akt isoforms show substantial compensation in many processes. However, the disruption of Akt2 and Akt3 significantly reduced neuron viability and axon length. These changes correlated with a tendency to increase in active caspase 3 and a decrease in the phosphorylation of some elements of the mTORC1 pathway. Indeed, the decrease of Akt2 and more evident the inhibition of Akt3 reduced the expression and phosphorylation of S6. All these data indicate that Akt2 and Akt3 specifically regulate some aspects of apoptosis and cell growth in cultured neurons and may contribute to the understanding of mechanisms of neuron death and pathologies that show deregulated growth.
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Affiliation(s)
- Hector Diez
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) and Centro de Biología Molecular “Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, Madrid, Spain
| | - Juan Jose Garrido
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) and Centro de Biología Molecular “Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, Madrid, Spain
- Laboratory of Neuronal Polarity, Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
| | - Francisco Wandosell
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) and Centro de Biología Molecular “Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, Madrid, Spain
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Zappaterra MW, Lehtinen MK. The cerebrospinal fluid: regulator of neurogenesis, behavior, and beyond. Cell Mol Life Sci 2012; 69:2863-78. [PMID: 22415326 DOI: 10.1007/s00018-012-0957-x] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 02/28/2012] [Accepted: 03/01/2012] [Indexed: 12/11/2022]
Abstract
The cerebrospinal fluid (CSF) has attracted renewed interest as an active signaling milieu that regulates brain development, homeostasis, and disease. Advances in proteomics research have enabled an improved characterization of the CSF from development through adulthood, and key neurogenic signaling pathways that are transmitted via the CSF are now being elucidated. Due to its immediate contact with neural stem cells in the developing and adult brain, the CSF's ability to swiftly distribute signals across vast distances in the central nervous system is opening avenues to novel and exciting therapeutic approaches. In this review, we will discuss the development of the choroid plexus-CSF system, and review the current literature on how the CSF actively regulates mammalian brain development, behavior, and responses to traumatic brain injury.
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Affiliation(s)
- Mauro W Zappaterra
- Department of Physical Medicine and Rehabilitation, VA Greater Los Angeles Healthcare System, 11301 Wilshire Blvd, Los Angeles, CA 90073, USA.
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43
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Yu W, Chen J, Xiong Y, Pixley FJ, Yeung YG, Stanley ER. Macrophage proliferation is regulated through CSF-1 receptor tyrosines 544, 559, and 807. J Biol Chem 2012; 287:13694-704. [PMID: 22375015 DOI: 10.1074/jbc.m112.355610] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Colony-stimulating factor-1 (CSF-1)-stimulated CSF-1 receptor (CSF-1R) tyrosine phosphorylation initiates survival, proliferation, and differentiation signaling pathways in macrophages. Either activation loop Y807F or juxtamembrane domain (JMD) Y559F mutations severely compromise CSF-1-regulated proliferation and differentiation. YEF, a CSF-1R in which all eight tyrosines phosphorylated in the activated receptor were mutated to phenylalanine, lacks in vitro kinase activity and in vivo CSF-1-regulated tyrosine phosphorylation. The addition of Tyr-807 alone to the YEF backbone (Y807AB) led to CSF-1-independent but receptor kinase-dependent proliferation, without detectable activation loop Tyr-807 phosphorylation. The addition of Tyr-559 alone (Y559AB) supported a low level of CSF-1-independent proliferation that was slightly enhanced by CSF-1, indicating that Tyr-559 has a positive Tyr-807-independent effect. Consistent with the postulated autoinhibitory role of the JMD Tyr-559 and its relief by ligand-induced Tyr-559 phosphorylation, the addition of Tyr-559 to the Y807AB background suppressed proliferation in the absence of CSF-1, but restored most of the CSF-1-stimulated proliferation. Full restoration of kinase activation and proliferation required the additional add back of JMD Tyr-544. Inhibitor experiments indicate that the constitutive proliferation of Y807AB macrophages is mediated by the phosphatidylinositol 3-kinase (PI3K) and ERK1/2 pathways, whereas proliferation of WT and Y559,807AB macrophages is, in addition, contributed to by Src family kinase (SFK)-dependent pathways. Thus Tyr-807 confers sufficient kinase activity for strong CSF-1-independent proliferation, whereas Tyr-559 maintains the receptor in an inactive state. Tyr-559 phosphorylation releases this restraint and may also contribute to the CSF-1-regulated proliferative response by activating Src family kinase.
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Affiliation(s)
- Wenfeng Yu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Diet and energy-sensing inputs affect TorC1-mediated axon misrouting but not TorC2-directed synapse growth in a Drosophila model of tuberous sclerosis. PLoS One 2012; 7:e30722. [PMID: 22319582 PMCID: PMC3272037 DOI: 10.1371/journal.pone.0030722] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 12/21/2011] [Indexed: 11/19/2022] Open
Abstract
The Target of Rapamycin (TOR) growth regulatory system is influenced by a number of different inputs, including growth factor signaling, nutrient availability, and cellular energy levels. While the effects of TOR on cell and organismal growth have been well characterized, this pathway also has profound effects on neural development and behavior. Hyperactivation of the TOR pathway by mutations in the upstream TOR inhibitors TSC1 (tuberous sclerosis complex 1) or TSC2 promotes benign tumors and neurological and behavioral deficits, a syndrome known as tuberous sclerosis (TS). In Drosophila, neuron-specific overexpression of Rheb, the direct downstream target inhibited by Tsc1/Tsc2, produced significant synapse overgrowth, axon misrouting, and phototaxis deficits. To understand how misregulation of Tor signaling affects neural and behavioral development, we examined the influence of growth factor, nutrient, and energy sensing inputs on these neurodevelopmental phenotypes. Neural expression of Pi3K, a principal mediator of growth factor inputs to Tor, caused synapse overgrowth similar to Rheb, but did not disrupt axon guidance or phototaxis. Dietary restriction rescued Rheb-mediated behavioral and axon guidance deficits, as did overexpression of AMPK, a component of the cellular energy sensing pathway, but neither was able to rescue synapse overgrowth. While axon guidance and behavioral phenotypes were affected by altering the function of a Tor complex 1 (TorC1) component, Raptor, or a TORC1 downstream element (S6k), synapse overgrowth was only suppressed by reducing the function of Tor complex 2 (TorC2) components (Rictor, Sin1). These findings demonstrate that different inputs to Tor signaling have distinct activities in nervous system development, and that Tor provides an important connection between nutrient-energy sensing systems and patterning of the nervous system.
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Sperow M, Berry RB, Bayazitov IT, Zhu G, Baker SJ, Zakharenko SS. Phosphatase and tensin homologue (PTEN) regulates synaptic plasticity independently of its effect on neuronal morphology and migration. J Physiol 2011; 590:777-92. [PMID: 22147265 DOI: 10.1113/jphysiol.2011.220236] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The tumour suppressor PTEN is the central negative regulator of the phosphatidylinositol 3-kinase (PI3K) signalling pathway, which mediates diverse processes in various tissues. In the nervous system, the PI3K pathway modulates proliferation, migration, cellular size, synaptic transmission and plasticity. In humans, neurological abnormalities such as autism, seizures and ataxia are associated with inherited PTEN mutations. In rodents, Pten loss during early development is associated with extensive deficits in neuronal migration and substantial hypertrophy of neurons and synaptic densities; however, whether its effect on synaptic transmission and plasticity is direct or mediated by structural abnormalities remains unknown. Here we analysed neuronal and synaptic structures and function in Pten-conditional knockout mice in which the gene was deleted from excitatory neurons postnatally. Using two-photon imaging, Golgi staining, immunohistochemistry, electron microscopy, and electrophysiological tools, we determined that Pten loss does not affect hippocampus development, neuronal or synaptic structures, or basal excitatory synaptic transmission. However, it does cause deficits in both major forms of synaptic plasticity, long-term potentiation and long-term depression, of excitatory synaptic transmission. These deficits coincided with impaired spatial memory, as measured in water maze tasks. Deletion of Pdk1, which encodes a positive downstream regulator of the PI3K pathway, rescued Pten-mediated deficits in synaptic plasticity but not in spatial memory. These results suggest that PTEN independently modulates functional and structural properties of hippocampal neurons and is directly involved in mechanisms of synaptic plasticity.
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Affiliation(s)
- Margaret Sperow
- Department of Developmental Neurobiology, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
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Abstract
Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism.
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Affiliation(s)
- Chang Hoon Cho
- Epilepsy Research Laboratory Department of Pediatrics Children's Hospital of Philadelphia, Pennsylvania 19104, USA.
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47
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Anaplastic lymphoma kinase spares organ growth during nutrient restriction in Drosophila. Cell 2011; 146:435-47. [PMID: 21816278 DOI: 10.1016/j.cell.2011.06.040] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 12/24/2010] [Accepted: 06/16/2011] [Indexed: 11/24/2022]
Abstract
Developing animals survive periods of starvation by protecting the growth of critical organs at the expense of other tissues. Here, we use Drosophila to explore the as yet unknown mechanisms regulating this privileged tissue growth. As in mammals, we observe in Drosophila that the CNS is more highly spared than other tissues during nutrient restriction (NR). We demonstrate that anaplastic lymphoma kinase (Alk) efficiently protects neural progenitor (neuroblast) growth against reductions in amino acids and insulin-like peptides during NR via two mechanisms. First, Alk suppresses the growth requirement for amino acid sensing via Slimfast/Rheb/TOR complex 1. And second, Alk, rather than insulin-like receptor, primarily activates PI3-kinase. Alk maintains PI3-kinase signaling during NR as its ligand, Jelly belly (Jeb), is constitutively expressed from a glial cell niche surrounding neuroblasts. Together, these findings identify a brain-sparing mechanism that shares some regulatory features with the starvation-resistant growth programs of mammalian tumors.
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Neurofibromatosis-1 regulates mTOR-mediated astrocyte growth and glioma formation in a TSC/Rheb-independent manner. Proc Natl Acad Sci U S A 2011; 108:15996-6001. [PMID: 21896734 DOI: 10.1073/pnas.1019012108] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Converging evidence from the analysis of human brain tumors and genetically engineered mice has revealed that the mammalian target of rapamycin (mTOR) pathway is a central regulator of glial and glioma cell growth. In this regard, mutational inactivation of neurofibromatosis-1 (NF1), tuberous sclerosis complex (TSC), and PTEN genes is associated with glioma formation, such that pharmacologic inhibition of mTOR signaling results in attenuated tumor growth. This shared dependence on mTOR suggests that PTEN and NF1 (neurofibromin) glial growth regulation requires TSC/Rheb (Ras homolog enriched in brain) control of mTOR function. In this report, we use a combination of genetic silencing in vitro and conditional mouse transgenesis approaches in vivo to demonstrate that neurofibromin regulates astrocyte cell growth and glioma formation in a TSC/Rheb-independent fashion. First, we show that Nf1 or Pten inactivation, but not Tsc1 loss or Rheb overexpression, increases astrocyte cell growth in vitro. Second, Nf1-deficient increased mTOR signaling and astrocyte hyperproliferation is unaffected by Rheb shRNA silencing. Third, conditional Tsc1 inactivation or Rheb overexpression in glial progenitors of Nf1(+/-) mice does not lead to glioma formation. Collectively, these findings establish TSC/Rheb-independent mechanisms for mTOR-dependent glial cell growth control and gliomagenesis relevant to the design of therapies for individuals with glioma.
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Abstract
Cerebral cortical progenitor cells can be classified into several different types, and each progenitor type integrates cell-intrinsic and cell-extrinsic cues to regulate neurogenesis. On one hand, cell-intrinsic mechanisms that depend upon appropriate apical-basal polarity are established by adherens junctions and apical complex proteins and are particularly important in progenitors with apical processes contacting the lateral ventricle. The apical protein complexes themselves are concentrated at the ventricular surface, and apical complex proteins regulate mitotic spindle orientation and cell fate. On the other hand, remarkably little is known about how cell-extrinsic cues signal to progenitors and couple with cell-intrinsic mechanisms to instruct neurogenesis. Recent research shows that the cerebrospinal fluid, which contacts apical progenitors at the ventricular surface and bathes the apical complex of these cells, provides growth- and survival-promoting cues for neural progenitor cells in developing and adult brain. This review addresses how the apical-basal polarity of progenitor cells regulates cell fate and allows progenitors to sample diffusible signals distributed by the cerebrospinal fluid. We also review several classes of signaling factors that the cerebrospinal fluid distributes to the developing brain to instruct neurogenesis.
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Affiliation(s)
- Maria K Lehtinen
- Division of Genetics, Howard Hughes Medical Institute, Boston, Massachusetts 02115, USA.
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50
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Ellwood-Yen K, Keilhack H, Kunii K, Dolinski B, Connor Y, Hu K, Nagashima K, O'Hare E, Erkul Y, Di Bacco A, Gargano D, Shomer NH, Angagaw M, Leccese E, Andrade P, Hurd M, Shin MK, Vogt TF, Northrup A, Bobkova EV, Kasibhatla S, Bronson RT, Scott ML, Draetta G, Richon V, Kohl N, Blume-Jensen P, Andersen JN, Kraus M. PDK1 attenuation fails to prevent tumor formation in PTEN-deficient transgenic mouse models. Cancer Res 2011; 71:3052-65. [PMID: 21493594 DOI: 10.1158/0008-5472.can-10-2282] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PDK1 activates AKT suggesting that PDK1 inhibition might suppress tumor development. However, while PDK1 has been investigated intensively as an oncology target, selective inhibitors suitable for in vivo studies have remained elusive. In this study we present the results of in vivo PDK1 inhibition through a universally applicable RNAi approach for functional drug target validation in oncogenic pathway contexts. This approach, which relies on doxycycline-inducible shRNA expression from the Rosa26 locus, is ideal for functional studies of genes like PDK1 where constitutive mouse models lead to strong developmental phenotypes or embryonic lethality. We achieved more than 90% PDK1 knockdown in vivo, a level sufficient to impact physiological functions resulting in hyperinsulinemia and hyperglycemia. This phenotype was reversible on PDK1 reexpression. Unexpectedly, long-term PDK1 knockdown revealed a lack of potent antitumor efficacy in 3 different mouse models of PTEN-deficient cancer. Thus, despite efficient PDK1 knockdown, inhibition of the PI3K pathway was marginal suggesting that PDK1 was not a rate limiting factor. Ex vivo analysis of pharmacological inhibitors revealed that AKT and mTOR inhibitors undergoing clinical development are more effective than PDK1 inhibitors at blocking activated PI3K pathway signaling. Taken together our findings weaken the widely held expectation that PDK1 represents an appealing oncology target.
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