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Lee HC, Hsieh CC, Tsai HJ. KEPI plays a negative role in the repression that accompanies translational inhibition guided by the uORF element of human CHOP transcript during stress response. Gene X 2022; 817:146160. [PMID: 35031423 DOI: 10.1016/j.gene.2021.146160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/28/2021] [Accepted: 12/10/2021] [Indexed: 11/04/2022] Open
Abstract
Translation of the downstream coding sequence of some mRNAs may be repressed by the upstream open reading frame (uORF) at their 5'-end. The mechanism underlying this uORF-mediated translational inhibition (uORF-MTI) is not fully understood in vivo. Recently, it was found that zebrafish Endouc or its human orthologue ENDOU (Endouc/ENDOU) plays a positive role in repressing the uORF-MTI of human CHOP (uORFchop-MTI) during stress by blocking its activity However, the repression of uORFchop-MTI assisted by an as-yet unidentified negative effector remains to be elucidated. Compared to the upregulated CHOP transcript, we herein report that the kepi (kinase-enhanced PP1 inhibitor) transcript was downregulated in the zebrafish embryos treated with both heat shock and hypoxia. Quantitative RT-PCR also revealed that the level of kepi mRNA was noticeably decreased in both heat-shock-treated and hypoxia-exposed embryos. When kepi mRNA was microinjected into the one-celled embryos from transgenic line huORFZ, the translation of downstream GFP reporter controlled by the uORFchop-MTI was reduced in the hypoxia-exposed embryos. In contrast, when kepi was knocked down by injection of antisense Morpholino oligonucleotide, the translation of downstream GFP reporter was induced and expressed in the brain and spinal cord of injected embryos in the absence of stress. During normal condition, overexpression of KEPI increased eIF2α phosphorylation, resulting in inducing the translation of uORF-tag mRNA, such as ATF4 and CHOP mRNAs. However, during stress condition, overexpression of KEPI decreased eIF2α phosphorylation, resulting in reducing the GFP reporter and CHOP proteins. This is the first report to demonstrate that KEPI plays a negative role in uORFchop - mediated translation during ER stress.
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Affiliation(s)
- Hung-Chieh Lee
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Chi-Cheng Hsieh
- The Liver Disease Prevention and Treatment Research Foundation, Taipei, Taiwan
| | - Huai-Jen Tsai
- Department of Life Science, Fu-Jen Catholic University, New Taipei City, Taiwan; School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan.
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2
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Jee HY, Lee YG, Lee S, Elvira R, Seo HE, Lee JY, Han J, Lee K. Activation of ERK and p38 Reduces AZD8055-Mediated Inhibition of Protein Synthesis in Hepatocellular Carcinoma HepG2 Cell Line. Int J Mol Sci 2021; 22:ijms222111824. [PMID: 34769253 PMCID: PMC8584319 DOI: 10.3390/ijms222111824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
Protein synthesis is important for maintaining cellular homeostasis under various stress responses. In this study, we screened an anticancer drug library to select compounds with translational repression functions. AZD8055, an ATP-competitive mechanistic target of rapamycin complex 1/2 (mTORC1/2) inhibitor, was selected as a translational suppressor. AZD8055 inhibited protein synthesis in mouse embryonic fibroblasts and hepatocellular carcinoma HepG2 cells. Extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) were activated during the early phase of mTORC1/2 inhibition by AZD8055 treatment. Combined treatment of AZD8055 with the MAPK kinase1/2 (MEK1/2) inhibitor refametinib or the p38 inhibitor SB203580 markedly decreased translation in HepG2 cells. Thus, the inhibition of ERK1/2 or p38 may enhance the efficacy of AZD8055-mediated inhibition of protein synthesis. In addition, AZD8055 down-regulated the phosphorylation of eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), and AZD8055-induced phosphorylation of ERK1/2 and p38 had no effect on phosphorylation status of 4E-BP1. Interestingly, AZD8055 modulated the 4E-BP1 mRNA pool by up-regulating ERK1/2 and p38 pathways. Together, these results suggest that AZD8055-induced activation of MAPKs interferes with inhibition of protein synthesis at an early stage of mTORC1/2 inhibition, and that it may contribute to the development of resistance to mTORC1/2 inhibitors.
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Affiliation(s)
- Ha-yeon Jee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea; (H.-y.J.); (Y.-G.L.); (S.L.); (H.-e.S.); (J.-Y.L.)
| | - Yoon-Gyeong Lee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea; (H.-y.J.); (Y.-G.L.); (S.L.); (H.-e.S.); (J.-Y.L.)
| | - Sol Lee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea; (H.-y.J.); (Y.-G.L.); (S.L.); (H.-e.S.); (J.-Y.L.)
| | - Rosalie Elvira
- Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan 31151, Korea; (R.E.); (J.H.)
| | - Hye-eun Seo
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea; (H.-y.J.); (Y.-G.L.); (S.L.); (H.-e.S.); (J.-Y.L.)
| | - Ji-Yeon Lee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea; (H.-y.J.); (Y.-G.L.); (S.L.); (H.-e.S.); (J.-Y.L.)
| | - Jaeseok Han
- Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan 31151, Korea; (R.E.); (J.H.)
| | - Kyungho Lee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea; (H.-y.J.); (Y.-G.L.); (S.L.); (H.-e.S.); (J.-Y.L.)
- Korea Hemp Institute, Konkuk University, Seoul 05029, Korea
- Correspondence: ; Tel.: +82-2-450-3423; Fax: +82-2-3436-5432
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Lin W, Jiang R, Hu S, Xiao X, Wu J, Wei S, Xiong Y, Ouyang G. Investigating the toxicities of different functionalized polystyrene nanoplastics on Daphnia magna. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:509-516. [PMID: 31125795 DOI: 10.1016/j.ecoenv.2019.05.036] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/10/2019] [Accepted: 05/12/2019] [Indexed: 05/22/2023]
Abstract
Nanoplastics (NPs) spread widely with water and air current, and they can accumulate in aquatic organisms, even penetrating biofilms, which may cause persistent toxicity and potential hazards. This current study aimed to reveal the toxicological mechanism of different functionalized polystyrene (PS) NPs on Daphnia magna (D. magna) by investigating toxicity endpoints in individual level and biochemical level. In this study, acute toxicity, behavioral parameters and biomarker responses of D. magna was measured in the exposure of different functionalized PS NPs (plain PS, PS-p-NH2, PS-n-NH2 and PS-COOH). The results indicated that when exposed to the plain PS, ROS induction would activate MAPKs, thereby causing lethality and adverse behavior effects on D. magna; while the functionalized PS NPs were less toxic than the plain PS, especially for PS-p-NH2 which was severely flocculated after exposure, thus showing no immobilization at the investigated concentrations. Also, the antioxidant system was mainly stimulated due to the direct interaction with the cell surface receptor, which was different from the plain PS. Consequently, this work suggests significant effects of functional groups on NPs for environmental toxicity studies, and provides a better understanding of the toxicological mechanism on the toxicity of PS NPs toward D. magna.
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Affiliation(s)
- Wei Lin
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Ruifen Jiang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
| | - Sizi Hu
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Xiaoying Xiao
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiayi Wu
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Songbo Wei
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Yaxin Xiong
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Gangfeng Ouyang
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China; College of Chemistry & Molecular Engineering, Center of Advanced Analysis and Computational Science, Zhengzhou University, Zhengzhou 450001, China.
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4
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Lee HR, Lee J, Kim HJ. Differential effects of MEK inhibitors on rat neural stem cell differentiation: Repressive roles of MEK2 in neurogenesis and induction of astrocytogenesis by PD98059. Pharmacol Res 2019; 149:104466. [PMID: 31562895 DOI: 10.1016/j.phrs.2019.104466] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 01/14/2023]
Abstract
Neural stem cells (NSCs) proliferate and differentiate into neurons and glia depending on the culture environment. However, the underlying mechanisms determining the fate of NSCs are not fully understood. Growth factors facilitate NSC proliferation through mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) and MAPK activation, and NSCs differentiate into neurons, astrocytes, or oligodendrocytes when mitogens are withdrawn from the culture media. Here, we aimed to identify the effects and roles of MEK signaling on the determination of NSC fate. MEK inhibitors, U0126, SL327, and PD98059, had differential effects on NSC differentiation. U0126 and SL327, which are known to inhibit MEK1 and MEK2, induced neuronal differentiation, whereas PD98059, which is reported to preferentially inhibit MEK1 at higher concentrations, increased astrocytogenesis. Knockdown of MEK2 using small interfering RNA increased neurogenesis and over-expression of wild type (WT) MEK2 inhibited neurogenesis, suggesting a repressive role of MEK2 in neuronal differentiation. The chemical structure of PD98059 appears to be important for induction of astrocytogenesis because not only PD98059 (2'-amino-3'-methoxyflavone) but also its chemical structural mimetic, 3'-methoxyflavone, enhanced astrocytogenesis. Therefore, in our study, we suggest that MEK inhibitors have distinct functions in determining NSC fate. Inhibition of MEK2 is important for induction of neurogenesis in NSCs. U0126 and SL327 increase neurogenesis through MEK2 inhibition, whereas PD98059 induced astrocytogenesis in NSCs, which is mediated by the chemical structure, particularly the 3'-methoxy group rather than its renowned MEK1 inhibition.
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Affiliation(s)
- Ha-Rim Lee
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea
| | - Jeewoo Lee
- College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Hyun-Jung Kim
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea.
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Koley S, Rozenbaum M, Fainzilber M, Terenzio M. Translating regeneration: Local protein synthesis in the neuronal injury response. Neurosci Res 2019; 139:26-36. [DOI: 10.1016/j.neures.2018.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/13/2018] [Accepted: 10/02/2018] [Indexed: 12/21/2022]
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Santos M, Pereira PM, Varanda AS, Carvalho J, Azevedo M, Mateus DD, Mendes N, Oliveira P, Trindade F, Pinto MT, Bordeira-Carriço R, Carneiro F, Vitorino R, Oliveira C, Santos MAS. Codon misreading tRNAs promote tumor growth in mice. RNA Biol 2018; 15:773-786. [PMID: 29558247 DOI: 10.1080/15476286.2018.1454244] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Deregulation of tRNAs, aminoacyl-tRNA synthetases and tRNA modifying enzymes are common in cancer, raising the hypothesis that protein synthesis efficiency and accuracy (mistranslation) are compromised in tumors. We show here that human colon tumors and xenograft tumors produced in mice by two epithelial cancer cell lines mistranslate 2- to 4-fold more frequently than normal tissue. To clarify if protein mistranslation plays a role in tumor biology, we expressed mutant Ser-tRNAs that misincorporate Ser-at-Ala (frequent error) and Ser-at-Leu (infrequent error) in NIH3T3 cells and investigated how they responded to the proteome instability generated by the amino acid misincorporations. There was high tolerance to both misreading tRNAs, but the Ser-to-Ala misreading tRNA was a more potent inducer of cell transformation, stimulated angiogenesis and produced faster growing tumors in mice than the Ser-to-Leu misincorporating tRNA. Upregulation of the Akt pathway and the UPR were also observed. Most surprisingly, the relative expression of both misreading tRNAs increased during tumor growth, suggesting that protein mistranslation is advantageous in cancer contexts. These data highlight new features of protein synthesis deregulation in tumor biology.
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Affiliation(s)
- Mafalda Santos
- a Department of Medical Sciences and Institute of Biomedicine - iBiMED , University of Aveiro , Aveiro , Portugal.,b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Patricia M Pereira
- a Department of Medical Sciences and Institute of Biomedicine - iBiMED , University of Aveiro , Aveiro , Portugal.,b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal
| | - A Sofia Varanda
- a Department of Medical Sciences and Institute of Biomedicine - iBiMED , University of Aveiro , Aveiro , Portugal.,b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Joana Carvalho
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Mafalda Azevedo
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal
| | - Denisa D Mateus
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal
| | - Nuno Mendes
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Patricia Oliveira
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Fábio Trindade
- a Department of Medical Sciences and Institute of Biomedicine - iBiMED , University of Aveiro , Aveiro , Portugal.,d Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine , University of Porto , Porto , Portugal
| | - Marta Teixeira Pinto
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Renata Bordeira-Carriço
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal
| | - Fátima Carneiro
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal.,e Dept. of Pathology, Faculty of Medicine , University of Porto , Porto , Portugal
| | - Rui Vitorino
- a Department of Medical Sciences and Institute of Biomedicine - iBiMED , University of Aveiro , Aveiro , Portugal
| | - Carla Oliveira
- b Expression Regulation in Cancer, Institute of Molecular Pathology and Immunology, University of Porto (IPATIMUP) , Porto , Portugal.,c Instituto de Investigação e Inovação em Saúde, University of Porto , Porto , Portugal.,e Dept. of Pathology, Faculty of Medicine , University of Porto , Porto , Portugal
| | - Manuel A S Santos
- a Department of Medical Sciences and Institute of Biomedicine - iBiMED , University of Aveiro , Aveiro , Portugal
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Role of the ERK1/2 Signaling Pathway in the Replication of Junín and Tacaribe Viruses. Viruses 2018; 10:v10040199. [PMID: 29673133 PMCID: PMC5923493 DOI: 10.3390/v10040199] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 01/12/2023] Open
Abstract
We have previously shown that the infection of cell cultures with the arenaviruses Junín (JUNV), Tacaribe (TCRV), and Pichindé promotes the phosphorylation of mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinases 1 and 2 (ERK1/2) and that this activation is required for the achievement of a productive infection. Here we examined the contribution of ERK1/2 in early steps of JUNV and TCRV multiplication. JUNV adsorption, internalization, and uncoating were not affected by treatment of cultured cells with U0126, an inhibitor of the ERK1/2 signaling pathway. In contrast, U0126 caused a marked reduction in viral protein expression and RNA synthesis, while JUNV RNA synthesis was significantly augmented in the presence of an activator of the ERK1/2 pathway. Moreover, U0126 impaired the expression of a reporter gene in a TCRV-based replicon system, confirming the ability of the compound to hinder arenavirus macromolecular synthesis. By using a cell-based assay, we determined that the inhibitor did not affect the translation of a synthetic TCRV-like mRNA. No changes in the phosphorylation pattern of the translation factor eIF2α were found in U0126-treated cells. Our results indicate that U0126 impairs viral RNA synthesis, thereby leading to a subsequent reduction in viral protein expression. Thus, we conclude that ERK1/2 signaling activation is required for an efficient arenavirus RNA synthesis.
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Oliveira JM, da Cruz e Silva CB, Müller T, Martins TS, Cova M, da Cruz e Silva OAB, Henriques AG. Toward Neuroproteomics in Biological Psychiatry: A Systems Approach Unravels Okadaic Acid-Induced Alterations in the Neuronal Phosphoproteome. ACTA ACUST UNITED AC 2017; 21:550-563. [DOI: 10.1089/omi.2017.0108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Joana Machado Oliveira
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | | | - Thorsten Müller
- Cell Signaling, Biochemistry II—Molecular Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Tânia Soares Martins
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Marta Cova
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Odete A. B. da Cruz e Silva
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Ana Gabriela Henriques
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
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Kim DH, Puthumana J, Kang HM, Lee MC, Jeong CB, Han J, Hwang DS, Kim IC, Lee JW, Lee JS. Adverse effects of MWCNTs on life parameters, antioxidant systems, and activation of MAPK signaling pathways in the copepod Paracyclopina nana. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 179:115-124. [PMID: 27595654 DOI: 10.1016/j.aquatox.2016.08.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Engineered multi-walled carbon nanotubes (MWCNTs) have received widespread applications in a broad variety of commercial products due to low production cost. Despite their significant commercial applications, CNTs are being discharged to aquatic ecosystem, leading a threat to aquatic life. Thus, we investigated the adverse effect of CNTs on the marine copepod Paracyclopina nana. Additional to the study on the uptake of CNTs and acute toxicity, adverse effects on life parameters (e.g. growth, fecundity, and size) were analyzed in response to various concentrations of CNTs. Also, as a measurement of cellular damage, oxidative stress-related markers were examined in a time-dependent manner. Moreover, activation of redox-sensitive mitogen-activated protein kinase (MAPK) signaling pathways along with the phosphorylation pattern of extracellular signal-regulated kinase (ERK), p38, and c-Jun-N-terminal kinases (JNK) were analyzed to obtain a better understanding of molecular mechanism of oxidative stress-induced toxicity in the copepod P. nana. As a result, significant inhibition on life parameters and evoked antioxidant systems were observed without ROS induction. In addition, CNTs activated MAPK signaling pathway via ERK, suggesting that phosphorylated ERK (p-ERK)-mediated adverse effects are the primary cause of in vitro and in vivo endpoints in response to CNTs exposure. Moreover, ROS-independent activation of MAPK signaling pathway was observed. These findings will provide a better understanding of the mode of action of CNTs on the copepod P. nana at cellular and molecular level and insight on possible ecotoxicological implications in the marine environment.
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Affiliation(s)
- Duck-Hyun Kim
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Jayesh Puthumana
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hye-Min Kang
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Min-Chul Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Chang-Bum Jeong
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Jeonghoon Han
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Dae-Sik Hwang
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Il-Chan Kim
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, South Korea
| | - Jin Wuk Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
| | - Jae-Seong Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
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Lee JW, Kang HM, Won EJ, Hwang DS, Kim DH, Lee SJ, Lee JS. Multi-walled carbon nanotubes (MWCNTs) lead to growth retardation, antioxidant depletion, and activation of the ERK signaling pathway but decrease copper bioavailability in the monogonont rotifer (Brachionus koreanus). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 172:67-79. [PMID: 26773353 DOI: 10.1016/j.aquatox.2015.12.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 12/25/2015] [Accepted: 12/29/2015] [Indexed: 05/06/2023]
Abstract
To examine the toxic effects of multi-walled carbon nanotubes (MWCNTs) in the marine environment, we first exposed the monogonont rotifer (Brachionus koreanus) to MWCNTs in the presence of copper. The acute toxicity of copper decreased significantly with a decrease in copper bioavailability resulting from MWCNT exposure. Furthermore, we examined the effects of MWCNT exposure on reproductive capacity, population growth rate, growth patterns, antioxidant systems, and mitogen-activated protein kinase (MAPK) activation. Reproductive capacity, population growth rate, and body growth rate were significantly suppressed in B. koreanus in response to 1.3-4mg/L MWCNT exposure. Furthermore, MWCNTs induced the generation of reactive oxygen species (ROS) and decreased the antioxidant enzymatic activities of catalase (CAT) and glutathione reductase (GR). However, the enzymatic activity of glutathione S-transferase (GST) was up-regulated after a 24 h-exposure to 100mg/L MWCNTs. Exposure to 100mg/L MCWNTs induced extracellular signal-regulated kinase (ERK) activation in B. koreanus, suggesting that p-ERK may mediate the adverse effects of MWCNTs in B. koreanus via the MAPK signaling pathway. Our results provide insight into the mechanistic basis of the ecotoxicological effects of MWCNTs in the marine environment.
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Affiliation(s)
- Jin Wuk Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hye-Min Kang
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Eun-Ji Won
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Dae-Sik Hwang
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Duck-Hyun Kim
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Su-Jae Lee
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 04763, South Korea
| | - Jae-Seong Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
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Karanika S, Karantanos T, Kurosaka S, Wang J, Hirayama T, Yang G, Park S, Golstov AA, Tanimoto R, Li L, Thompson TC. GLIPR1-ΔTM synergizes with docetaxel in cell death and suppresses resistance to docetaxel in prostate cancer cells. Mol Cancer 2015; 14:122. [PMID: 26084402 PMCID: PMC4484888 DOI: 10.1186/s12943-015-0395-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/29/2015] [Indexed: 12/14/2022] Open
Abstract
Background Docetaxel is the first chemotherapy agent approved for treatment of metastatic castration-resistant prostate cancer (mCRPC). The limited survival benefit associated with the quick emergence of resistance and systemic toxicity diminished its efficacy. JNK-mediated apoptosis is one of the mechanisms of docetaxel activity whereas ERK1/2-c-Myc-CXCR4 signaling is implicated in the development of resistance and induction of migration. The aim of this study was to evaluate the hypothesis that the combination treatment with docetaxel and GLIPR1-ΔTM will synergistically induce greater cell death and inhibit the emergence of resistance and development of metastatic potential in prostate cancer (PCa) cells. Methods The synergistic effects of the docetaxel and GLIPR1-ΔTM were evaluated with DNA fragmentation, DAPI staining and MTS using paired t-test and isobologram study. The effects of the drugs on JNK and ERK1/2-c-Myc-CXCR4 signaling were evaluated with Western blot, DNA fragmentation, and MTS assays using the JNK inhibitor SP600125, and CXCR4 siRNA. The results of docetaxel and GLIPR1-ΔTM combination on migration were examined with scratch assay using the CXCR4 inhibitor AMD3100 while our hypothesis was examined in vivo using VCaP orthotopic xenograft model. Results We found that GLIPR1-ΔΤΜ synergized with docetaxel to induce apoptosis in VCaP and PC-3 PCa cells through induction of JNK signaling and concomitant inhibition of ERK1/2-c-Myc-CXCR4 signaling. We showed that JNK activation mediates the apoptotic effects of the drug combination and that CXCR4 knockdown increases its efficacy. We also found that the addition of GLIPR1-ΔΤΜ to docetaxel decreases the migration of VCaP and PC-3 cells. The combination treatment with docetaxel and GLIPR1-ΔTM inhibited tumor growth and decreased metastatic potential in VCaP xenografts more than single agents did. Conclusions Our data suggested that addition of GLIPR1-ΔTM treatment in PCa cells increases the efficacy of docetaxel and may inhibit the emergence of drug resistance; potentially permitting a decrease of docetaxel dose for patients with mCRPC eliminating its systemic toxicities. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0395-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Styliani Karanika
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
| | - Theodoros Karantanos
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
| | - Shinji Kurosaka
- Department of Urology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.
| | - Jianxiang Wang
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
| | - Takahiro Hirayama
- Department of Urology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.
| | - Guang Yang
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
| | - Sanghee Park
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
| | - Alexei A Golstov
- Department of Thoracic & Cardio Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Ryuta Tanimoto
- Department of Urology, Thomas Jefferson University Hospital, Philadelphia, PA, USA.
| | - Likun Li
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
| | - Timothy C Thompson
- Department of Genitourinary Medical Oncology - Research, Unit 18-3, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, USA.
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Netrin-1 exerts oncogenic activities through enhancing Yes-associated protein stability. Proc Natl Acad Sci U S A 2015; 112:7255-60. [PMID: 26039999 DOI: 10.1073/pnas.1505917112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Yes-associated protein (YAP), a transcription coactivator, is the major downstream effector of the Hippo pathway, which plays a critical role in organ size control and cancer development. However, how YAP is regulated by extracellular stimuli in tumorigenesis remains incompletely understood. Netrin-1, a laminin-related secreted protein, displays proto-oncogenic activity in cancers. Nonetheless, the downstream signaling mediating its oncogenic effects is not well defined. Here we show that netrin-1 via its transmembrane receptors, deleted in colorectal cancer and uncoordinated-5 homolog, up-regulates YAP expression, escalating YAP levels in the nucleus and promoting cancer cell proliferation and migration. Inactivating netrin-1, deleted in colorectal cancer, or uncoordinated-5 homolog B (UNC5B) decreases YAP protein levels, abrogating cancer cell progression by netrin-1, whereas knockdown of mammalian STE20-like protein kinase 1/2 (MST1/2) or large tumor suppressor kinase 1/2 (Lats1/2), two sets of upstream core kinases of the Hippo pathway, has no effect in blocking netrin-1-induced up-regulation of YAP. Netrin-1 stimulates phosphatase 1A to dephosphorylate YAP, which leads to decreased ubiquitination and degradation, enhancing YAP accumulation and signaling. Hence, our findings support that netrin-1 exerts oncogenic activity through YAP signaling, providing a mechanism coupling extracellular signals to the nuclear YAP oncogene.
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Roy Chowdhury S, Sengupta S, Biswas S, Sinha TK, Sen R, Basak RK, Adhikari B, Bhattacharyya A. Bacterial fucose-rich polysaccharide stabilizes MAPK-mediated Nrf2/Keap1 signaling by directly scavenging reactive oxygen species during hydrogen peroxide-induced apoptosis of human lung fibroblast cells. Methods Enzymol 2014; 528:27-48. [PMID: 25412177 DOI: 10.1016/b978-0-12-405881-1.00002-1] [Citation(s) in RCA: 330] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Continuous free radical assault upsets cellular homeostasis and dysregulates associated signaling pathways to promote stress-induced cell death. In spite of the continuous development and implementation of effective therapeutic strategies, limitations in treatments for stress-induced toxicities remain. The purpose of the present study was to determine the potential therapeutic efficacy of bacterial fucose polysaccharides against hydrogen peroxide (H2O2)-induced stress in human lung fibroblast (WI38) cells and to understand the associated molecular mechanisms. In two different fermentation processes, Bacillus megaterium RB-05 biosynthesized two non-identical fucose polysaccharides; of these, the polysaccharide having a high-fucose content (∼ 42%) conferred the maximum free radical scavenging efficiency in vitro. Structural characterizations of the purified polysaccharides were performed using HPLC, GC-MS, and (1)H/(13)C/2D-COSY NMR. H2O2 (300 µM) insult to WI38 cells showed anti-proliferative effects by inducing intracellular reactive oxygen species (ROS) and by disrupting mitochondrial membrane permeability, followed by apoptosis. The polysaccharide (250 µg/mL) attenuated the cell death process by directly scavenging intracellular ROS rather than activating endogenous antioxidant enzymes. This process encompasses inhibition of caspase-9/3/7, a decrease in the ratio of Bax/Bcl2, relocalization of translocated Bax and cytochrome c, upregulation of anti-apoptotic members of the Bcl2 family and a decrease in the phosphorylation of MAPKs (mitogen activated protein kinases). Furthermore, cellular homeostasis was re-established via stabilization of MAPK-mediated Nrf2/Keap1 signaling and transcription of downstream cytoprotective genes. This molecular study uniquely introduces a fucose-rich bacterial polysaccharide as a potential inhibitor of H2O2-induced stress and toxicities.
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Affiliation(s)
- Sougata Roy Chowdhury
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India; Immunology lab, Department of Zoology, University of Calcutta, West Bengal, India
| | - Suman Sengupta
- Immunology lab, Department of Zoology, University of Calcutta, West Bengal, India
| | - Subir Biswas
- Immunology lab, Department of Zoology, University of Calcutta, West Bengal, India
| | - Tridib Kumar Sinha
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India
| | - Ramkrishna Sen
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal, India
| | - Ratan Kumar Basak
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India
| | - Basudam Adhikari
- Materials Science Centre, Indian Institute of Technology Kharagpur, West Bengal, India
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Jung EJ, Park HC, Chung KH, Kim CW. Proteomic analysis of SP600125-controlled TrkA-dependent targets in SK-N-MC neuroblastoma cells: inhibition of TrkA activity by SP600125. Proteomics 2014; 14:202-15. [PMID: 24375967 DOI: 10.1002/pmic.201300023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 11/13/2013] [Accepted: 12/01/2013] [Indexed: 12/12/2022]
Abstract
The c-Jun N-terminal kinase (JNK) is well known to play an important role in cell death signaling of the p75 neurotrophin receptor. However, little has been studied about a role of JNK in the signaling pathways of the tropomyosin-related kinase A (TrkA) neurotrophin receptor. In this study, we investigated JNK inhibitor SP600125-controlled TrkA-dependent targets by proteomic analysis to better understand an involvement of JNK in TrkA-mediated signaling pathways. PDQuest image analysis and protein identification results showed that hnRNP C1/C2, α-tubulin, β-tubulin homolog, actin homolog, and eIF-5A-1 protein spots were upregulated by ectopic expression of TrkA, whereas α-enolase, peroxiredoxin-6, PROS-27, HSP70, PP1-gamma, and PDH E1-alpha were downregulated by TrkA, and these TrkA-dependent upregulation and downregulation were significantly suppressed by SP600125. Notably, TrkA largely affected certain PTM(s) but not total protein amounts of the SP600125-controlled TrkA-dependent targets. Moreover, SP600125 strongly suppressed TrkA-mediated tyrosine phosphorylation signaling pathways as well as JNK signaling, indicating that SP600125 could function as a TrkA inhibitor. Taken together, our results suggest that TrkA could play an important role in the cytoskeleton, cell death, cellular processing, and glucose metabolism through activation or inactivation of the SP600125-controlled TrkA-dependent targets.
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Affiliation(s)
- Eun Joo Jung
- Department of Biochemistry, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, South Korea
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Zhang Z, Zheng Y, Zhu R, Zhu Y, Yao W, Liu W, Gao X. The ERK/eIF4F/Bcl-XL pathway mediates SGP-2 induced osteosarcoma cells apoptosis in vitro and in vivo. Cancer Lett 2014; 352:203-13. [DOI: 10.1016/j.canlet.2014.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/16/2014] [Accepted: 06/24/2014] [Indexed: 11/30/2022]
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Xu T, Wu X, Chen Q, Zhu S, Liu Y, Pan D, Chen X, Li D. The anti-apoptotic and cardioprotective effects of salvianolic acid a on rat cardiomyocytes following ischemia/reperfusion by DUSP-mediated regulation of the ERK1/2/JNK pathway. PLoS One 2014; 9:e102292. [PMID: 25019380 PMCID: PMC4096914 DOI: 10.1371/journal.pone.0102292] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 06/17/2014] [Indexed: 11/24/2022] Open
Abstract
The purpose of this study was to observe the effects of salvianolic acid A (SAA) pretreatment on the myocardium during ischemia/reperfusion (I/R) and to illuminate the interrelationships among dual specificity protein phosphatase (DUSP) 2/4/16, ERK1/2 and JNK pathways during myocardial I/R, with the ultimate goal of elucidating how SAA exerts cardioprotection against I/R injury (IRI). Wistar rats were divided into the following six groups: control group (CON), I/R group, SAA+I/R group, ERK1/2 inhibitor PD098059+I/R group (PD+I/R), PD+SAA+I/R group, and JNK inhibitor SP600125+I/R group (SP+I/R). The cardioprotective effects of SAA on the myocardium during I/R were investigated with a Langendorff device. Heart rate (HR), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximum rate of ventricular pressure rise and fall (±dp/dtmax), myocardial infarction areas (MIA), lactate dehydrogenase (LDH), and cardiomyocytes apoptosis were monitored. To determine the crosstalk betwee JNK and ERK1/2 via DUSP2/4/16 with SAA pretreatment, siRNA-DUSP2/4/16 were performed. The expression levels of Bcl-2, Bax, caspase 3, p-JNK, p-ERK1/2 and DUSP2/4/16 in cardiomyocytes were assayed by Western blot. Our results showed that LDH, MIA and cell apoptosis were decreased, and various parameters of heart function were improved by SAA pretreatment and SP application. In the I/R group, the expression levels of p-ERK1/2 and DUSP4/16 were not significantly different compared with the CON group, however, the protein expression levels of p-ERK1/2, Bcl-2 and DUSP4/16 were higher, while p-JNK, Bax, caspase 3 and DUSP2 levels were reduced among the SAA+I/R, PD+SAA+I/R and SP+I/R groups. The above indices were not significantly different between the SAA+I/R and SP+I/R groups. Compared with the SAA+I/R group, p-ERK1/2 was increased and p-JNK was decreased in the SAA+si-DUSP2+I/R, however, p-ERK was downregulated and p-JNK was upregulated in SAA+si-DUSP4+I/R group. SAA exerts an anti-apoptotic role against myocardial IRI by inhibiting DUSP2-mediated JNK dephosphorylation and activating DUSP4/16-mediated ERK1/2 phosphorylation.
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Affiliation(s)
- Tongda Xu
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
- The First Clinical College, Nanjing Traditional Chinese Medicine University, Nanjing, Jiangsu, China
| | - Xin Wu
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
| | - Qiuping Chen
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
| | - Shasha Zhu
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
| | - Yang Liu
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
| | - Defeng Pan
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
| | - Xiaohu Chen
- The First Clinical College, Nanjing Traditional Chinese Medicine University, Nanjing, Jiangsu, China
- * E-mail: (DL); (XC)
| | - Dongye Li
- Research Institute of Cardiovascular Diseases, Xuzhou Medical College, Xuzhou, Jiangsu, China
- The First Clinical College, Nanjing Traditional Chinese Medicine University, Nanjing, Jiangsu, China
- * E-mail: (DL); (XC)
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Lee HS, Hwang CY, Shin SY, Kwon KS, Cho KH. MLK3 is part of a feedback mechanism that regulates different cellular responses to reactive oxygen species. Sci Signal 2014; 7:ra52. [PMID: 24894995 DOI: 10.1126/scisignal.2005260] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Reactive oxygen species (ROS) influence diverse cellular processes, including proliferation and apoptosis. Both endogenous and exogenous ROS activate signaling through mitogen-activated proteins kinase (MAPK) pathways, including those involving extracellular signal-regulated kinases (ERKs) or c-Jun N-terminal kinases (JNKs). Whereas low concentrations of ROS generally stimulate proliferation, high concentrations result in cell death. We found that low concentrations of ROS induced activating phosphorylation of ERKs, whereas high concentrations of ROS induced activating phosphorylation of JNKs. Mixed lineage kinase 3 (MLK3, also known as MAP3K11) directly phosphorylates JNKs and may control activation of ERKs. Mathematical modeling of MAPK networks revealed a positive feedback loop involving MLK3 that determined the relative phosphorylation of ERKs and JNKs by ROS. Cells exposed to an MLK3 inhibitor or cells in which MLK3 was knocked down showed increased activation of ERKs and decreased activation of JNKs and were resistant to cell death when exposed to high concentrations of ROS. Thus, the data indicated that MLK3 is a critical factor controlling the activity of kinase networks that control the cellular responses to different concentrations of ROS.
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Affiliation(s)
- Ho-Sung Lee
- Laboratory for Systems Biology and Bio-Inspired Engineering, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea. Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Chae Young Hwang
- Laboratory for Systems Biology and Bio-Inspired Engineering, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea. Laboratory of Cell Signaling, Aging Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea
| | - Sung-Young Shin
- Laboratory for Systems Biology and Bio-Inspired Engineering, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Ki-Sun Kwon
- Laboratory of Cell Signaling, Aging Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
| | - Kwang-Hyun Cho
- Laboratory for Systems Biology and Bio-Inspired Engineering, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea. Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
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Nakatsu D, Kano F, Taguchi Y, Sugawara T, Nishizono T, Nishikawa K, Oda Y, Furuse M, Murata M. JNK1/2-dependent phosphorylation of angulin-1/LSR is required for the exclusive localization of angulin-1/LSR and tricellulin at tricellular contacts in EpH4 epithelial sheet. Genes Cells 2014; 19:565-81. [PMID: 24889144 DOI: 10.1111/gtc.12158] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 03/27/2014] [Indexed: 01/16/2023]
Abstract
Tricellular tight junctions (tTJs) are specialized structural variants of tight junctions within tricellular contacts of an epithelial sheet and comprise several transmembrane proteins including lipolysis-stimulated lipoprotein receptor (angulin-1/LSR) and tricellulin. To elucidate the mechanism of its formation, we carried out stepwise screening of kinase inhibitors followed by RNAi screening to identify kinases that regulate intracellular localization of angulin-1/LSR to the tTJs using a fluorescence image-based screen. We found that the activity of JNK1 and JNK2, but not JNK3, was required for the exclusive localization of angulin-1/LSR at the tTJs. Based on a bioinformatics approach, we estimated the potential phosphorylation site of angulin-1/LSR by JNK1 to be serine 288 and experimentally confirmed that JNK1 directly phosphorylates angulin-1/LSR at this site. We found that JNK2 was also involved in the phosphorylation of angulin-1/LSR. Furthermore, GFP-tagged angulin-1/LSR(S288A), in which serine 288 was substituted by alanine, was observed to be dispersed to bicellular junctions, indicating that phosphorylation of Ser288 is crucial for the exclusive localization of angulin-1/LSR and tricellulin at tTJs. Our fluorescence image-based screening for kinases inhibitor or siRNAs combined with the phosphorylation site prediction could become a versatile and useful tool to elucidate the mechanisms underlying the maintenance of tTJs regulated by kinase networks.
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Affiliation(s)
- Daiki Nakatsu
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan
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19
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Gross TJ, Powers LS, Boudreau RL, Brink B, Reisetter A, Goel K, Gerke AK, Hassan IH, Monick MM. A microRNA processing defect in smokers' macrophages is linked to SUMOylation of the endonuclease DICER. J Biol Chem 2014; 289:12823-34. [PMID: 24668803 PMCID: PMC4007470 DOI: 10.1074/jbc.m114.565473] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 03/24/2014] [Indexed: 11/06/2022] Open
Abstract
Despite the fact that alveolar macrophages play an important role in smoking-related disease, little is known about what regulates their pathophysiologic phenotype. Evaluating smoker macrophages, we found significant down-regulation of multiple microRNAs (miRNAs). This work investigates the hypothesis that cigarette smoke alters mature miRNA expression in lung macrophages by inhibiting processing of primary miRNA transcripts. Studies on smoker alveolar macrophages showed a defect in miRNA maturation. Studies on the miRNA biogenesis machinery led us to focus on the cytosolic RNA endonuclease, DICER. DICER cleaves the stem-loop structure from pre-miRNAs, allowing them to dissociate into their mature 20-22-nucleotide single-stranded form. DICER activity assays confirmed impaired DICER activity following cigarette smoke exposure. Further protein studies demonstrated a decreased expression of the native 217-kDa form of DICER and an accumulation of high molecular weight forms with cigarette smoke exposure. This molecular mass shift was shown to contain SUMO moieties and could be blocked by silencing RNA directed at the primary SUMOylating ligase, Ubc9. In determining the cigarette smoke components responsible for changes in DICER, we found that N-acetylcysteine, an antioxidant and anti-aldehyde, protected DICER protein and activity from cigarette smoke extract. This massive down-regulation of miRNAs (driven in part by alterations in DICER) may be an important regulator of the disease-promoting macrophage phenotype found in the lungs of smokers.
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Affiliation(s)
- Thomas J. Gross
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Linda S. Powers
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Ryan L. Boudreau
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Brandi Brink
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Anna Reisetter
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Khushboo Goel
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Alicia K. Gerke
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Ihab H. Hassan
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Martha M. Monick
- From the Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
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Hiroshima Y, Hsu K, Tedla N, Chung YM, Chow S, Herbert C, Geczy CL. S100A8 Induces IL-10 and Protects against Acute Lung Injury. THE JOURNAL OF IMMUNOLOGY 2014; 192:2800-11. [DOI: 10.4049/jimmunol.1302556] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Wu X, Xu T, Li D, Zhu S, Chen Q, Hu W, Pan D, Zhu H, Sun H. ERK/PP1a/PLB/SERCA2a and JNK pathways are involved in luteolin-mediated protection of rat hearts and cardiomyocytes following ischemia/reperfusion. PLoS One 2013; 8:e82957. [PMID: 24386130 PMCID: PMC3875429 DOI: 10.1371/journal.pone.0082957] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 10/29/2013] [Indexed: 11/19/2022] Open
Abstract
Luteolin has long been used in traditional Chinese medicine for treatment of various diseases. Recent studies have suggested that administration of luteolin yields cardioprotective effects during ischemia/reperfusion (I/R) in rats. However, the precise mechanisms of this action remain unclear. The aim of this study is to confirm that luteolin-mediated extracellular signal regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) pathways are responsible for their cardioprotective effects during I/R. Wistar rats were divided into the following groups: (i) DMSO group (DMSO); (ii) I/R group (I/R); (iii) luteolin+I/R group (Lut+I/R); (iv) ERK1/2 inhibitor PD98059+I/R group (PD+I/R); (v) PD98059+luteolin+I/R group (PD+Lut+I/R); and (vi) JNK inhibitor SP600125+I/R group (SP+I/R). The following properties were measured: contractile function of isolated heart and cardiomyocytes; infarct size; the release of lactate dehydrogenase (LDH); the percentage of apoptotic cells; the expression levels of Bcl-2 and Bax; and phosphorylation status of ERK1/2, JNK, type 1 protein phosphatase (PP1a), phospholamban (PLB) and sarcoplasmic reticulum Ca2+-ATPase (SERCA2a). Our data showed that pretreatment with luteolin or SP600125 significantly improved the contraction of the isolated heart and cardiomyocytes, reduced infarct size and LDH activity, decreased the rate of apoptosis and increased the Bcl-2/Bax ratio. However, pretreatment with PD98059 alone before I/R had no effect on the above indexes. Further, these consequences of luteolin pretreatment were abrogated by co-administration of PD98059. We also found that pretreatment with PD98059 caused a significant increase in JNK expression, and SP600125 could cause ERK1/2 activation during I/R. In addition, we are the first to demonstrate that luteolin affects PP1a expression, which results in the up-regulation of the PLB, thereby relieving its inhibition of SERCA2a. These results showed that luteolin improves cardiomyocyte contractile function after I/R injury by an ERK1/2-PP1a-PLB-SERCA2a-mediated mechanism independent of JNK signaling pathway.
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Affiliation(s)
- Xin Wu
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
| | - Tongda Xu
- Department of The First Clinical College, Nanjing Traditional Chinese Medicine University, Nanjing, Jiangsu, PR China
| | - Dongye Li
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
- Department of The First Clinical College, Nanjing Traditional Chinese Medicine University, Nanjing, Jiangsu, PR China
- * E-mail: (DL); (HS)
| | - Shasha Zhu
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
| | - Qiuping Chen
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
| | - Wenjing Hu
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
| | - Defeng Pan
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
| | - Hong Zhu
- Institute of Cardiovascular Disease Research, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu, PR China
- * E-mail: (DL); (HS)
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Monick MM, Baltrusaitis J, Powers LS, Borcherding JA, Caraballo JC, Mudunkotuwa I, Peate DW, Walters K, Thompson JM, Grassian VH, Gudmundsson G, Comellas AP. Effects of Eyjafjallajökull volcanic ash on innate immune system responses and bacterial growth in vitro. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:691-8. [PMID: 23478268 PMCID: PMC3672917 DOI: 10.1289/ehp.1206004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 03/07/2013] [Indexed: 05/24/2023]
Abstract
BACKGROUND On 20 March 2010, the Icelandic volcano Eyjafjallajökull erupted for the first time in 190 years. Despite many epidemiological reports showing effects of volcanic ash on the respiratory system, there are limited data evaluating cellular mechanisms involved in the response to ash. Epidemiological studies have observed an increase in respiratory infections in subjects and populations exposed to volcanic eruptions. METHODS We physicochemically characterized volcanic ash, finding various sizes of particles, as well as the presence of several transition metals, including iron. We examined the effect of Eyjafjallajökull ash on primary rat alveolar epithelial cells and human airway epithelial cells (20-100 µg/cm(2)), primary rat and human alveolar macrophages (5-20 µg/cm(2)), and Pseudomonas aeruginosa (PAO1) growth (3 µg/104 bacteria). RESULTS Volcanic ash had minimal effect on alveolar and airway epithelial cell integrity. In alveolar macrophages, volcanic ash disrupted pathogen-killing and inflammatory responses. In in vitro bacterial growth models, volcanic ash increased bacterial replication and decreased bacterial killing by antimicrobial peptides. CONCLUSIONS These results provide potential biological plausibility for epidemiological data that show an association between air pollution exposure and the development of respiratory infections. These data suggest that volcanic ash exposure, while not seriously compromising lung cell function, may be able to impair innate immunity responses in exposed individuals.
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Affiliation(s)
- Martha M Monick
- Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Osaki LH, Gama P. MAPKs and signal transduction in the control of gastrointestinal epithelial cell proliferation and differentiation. Int J Mol Sci 2013; 14:10143-61. [PMID: 23670595 PMCID: PMC3676833 DOI: 10.3390/ijms140510143] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 02/06/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathways are activated by several stimuli and transduce the signal inside cells, generating diverse responses including cell proliferation, differentiation, migration and apoptosis. Each MAPK cascade comprises a series of molecules, and regulation takes place at different levels. They communicate with each other and with additional pathways, creating a signaling network that is important for cell fate determination. In this review, we focus on ERK, JNK, p38 and ERK5, the major MAPKs, and their interactions with PI3K-Akt, TGFβ/Smad and Wnt/β-catenin pathways. More importantly, we describe how MAPKs regulate cell proliferation and differentiation in the rapidly renewing epithelia that lines the gastrointestinal tract and, finally, we highlight the recent findings on nutritional aspects that affect MAPK transduction cascades.
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Affiliation(s)
- Luciana H Osaki
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, SP 05508-000, Brazil.
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Chung YM, Goyette J, Tedla N, Hsu K, Geczy CL. S100A12 suppresses pro-inflammatory, but not pro-thrombotic functions of serum amyloid A. PLoS One 2013; 8:e62372. [PMID: 23638054 PMCID: PMC3634854 DOI: 10.1371/journal.pone.0062372] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/20/2013] [Indexed: 12/15/2022] Open
Abstract
S100A12 is elevated in the circulation in patients with chronic inflammatory diseases and recent studies indicate pleiotropic functions. Serum amyloid A induces monocyte cytokines and tissue factor. S100A12 did not stimulate IL-6, IL-8, IL-1β or TNF-α production by human peripheral blood mononuclear cells but low amounts consistently reduced cytokine mRNA and protein levels induced by serum amyloid A, by ∼49% and ∼46%, respectively. However, S100A12 did not affect serum amyloid A-induced monocyte tissue factor. In marked contrast, LPS-induced cytokines or tissue factor were not suppressed by S100A12. S100A12 did not alter cytokine mRNA stability or the cytokine secretory pathway. S100A12 and serum amyloid A did not appear to form complexes and although they may have common receptors, suppression was unlikely via receptor competition. Serum amyloid A induces cytokines via activation of NF-κB and the MAPK pathways. S100A12 reduced serum amyloid A-, but not LPS-induced ERK1/2 phosphorylation to baseline. It did not affect JNK or p38 phosphorylation or the NF-κB pathway. Reduction in ERK1/2 phosphorylation by S100A12 was unlikely due to changes in intracellular reactive oxygen species, Ca2+ flux or to recruitment of phosphatases. We suggest that S100A12 may modulate sterile inflammation by blunting pro-inflammatory properties of lipid-poor serum amyloid A deposited in chronic lesions where both proteins are elevated as a consequence of macrophage activation.
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Affiliation(s)
- Yuen Ming Chung
- Inflammation and Infection Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Jesse Goyette
- Inflammation and Infection Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Nicodemus Tedla
- Inflammation and Infection Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Kenneth Hsu
- Inflammation and Infection Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Carolyn L. Geczy
- Inflammation and Infection Research Centre, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
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Fey D, Croucher DR, Kolch W, Kholodenko BN. Crosstalk and signaling switches in mitogen-activated protein kinase cascades. Front Physiol 2012; 3:355. [PMID: 23060802 PMCID: PMC3449335 DOI: 10.3389/fphys.2012.00355] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/19/2012] [Indexed: 12/24/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) cascades control cell fate decisions, such as proliferation, differentiation, and apoptosis by integrating and processing intra- and extracellular cues. However, similar MAPK kinetic profiles can be associated with opposing cellular decisions depending on cell type, signal strength, and dynamics. This implies that signaling by each individual MAPK cascade has to be considered in the context of the entire MAPK network. Here, we develop a dynamic model of feedback and crosstalk for the three major MAPK cascades; extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (p38), c-Jun N-terminal kinase (JNK), and also include input from protein kinase B (AKT) signaling. Focusing on the bistable activation characteristics of the JNK pathway, this model explains how pathway crosstalk harmonizes different MAPK responses resulting in pivotal cell fate decisions. We show that JNK can switch from a transient to sustained activity due to multiple positive feedback loops. Once activated, positive feedback locks JNK in a highly active state and promotes cell death. The switch is modulated by the ERK, p38, and AKT pathways. ERK activation enhances the dual specificity phosphatase (DUSP) mediated dephosphorylation of JNK and shifts the threshold of the apoptotic switch to higher inputs. Activation of p38 restores the threshold by inhibiting ERK activity via the PP1 or PP2A phosphatases. Finally, AKT activation inhibits the JNK positive feedback, thus abrogating the apoptotic switch and allowing only proliferative signaling. Our model facilitates understanding of how cancerous deregulations disturb MAPK signal processing and provides explanations for certain drug resistances. We highlight a critical role of DUSP1 and DUSP2 expression patterns in facilitating the switching of JNK activity and show how oncogene induced ERK hyperactivity prevents the normal apoptotic switch explaining the failure of certain drugs to induce apoptosis.
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Affiliation(s)
- Dirk Fey
- Systems Biology Ireland, University College Dublin Dublin, Ireland
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26
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Graff JW, Powers LS, Dickson AM, Kim J, Reisetter AC, Hassan IH, Kremens K, Gross TJ, Wilson ME, Monick MM. Cigarette smoking decreases global microRNA expression in human alveolar macrophages. PLoS One 2012; 7:e44066. [PMID: 22952876 PMCID: PMC3430644 DOI: 10.1371/journal.pone.0044066] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 07/30/2012] [Indexed: 01/21/2023] Open
Abstract
Human alveolar macrophages are critical components of the innate immune system. Cigarette smoking-induced changes in alveolar macrophage gene expression are linked to reduced resistance to pulmonary infections and to the development of emphysema/COPD. We hypothesized that microRNAs (miRNAs) could control, in part, the unique messenger RNA (mRNA) expression profiles found in alveolar macrophages of cigarette smokers. Activation of macrophages with different stimuli in vitro leads to a diverse range of M1 (inflammatory) and M2 (anti-inflammatory) polarized phenotypes that are thought to mimic activated macrophages in distinct tissue environments. Microarray mRNA data indicated that smoking promoted an "inverse" M1 mRNA expression program, defined by decreased expression of M1-induced transcripts and increased expression of M1-repressed transcripts with few changes in M2-regulated transcripts. RT-PCR arrays identified altered expression of many miRNAs in alveolar macrophages of smokers and a decrease in global miRNA abundance. Stratification of human subjects suggested that the magnitude of the global decrease in miRNA abundance was associated with smoking history. We found that many of the miRNAs with reduced expression in alveolar macrophages of smokers were predicted to target mRNAs upregulated in alveolar macrophages of smokers. For example, miR-452 is predicted to target the transcript encoding MMP12, an important effector of smoking-related diseases. Experimental antagonism of miR-452 in differentiated monocytic cells resulted in increased expression of MMP12. The comprehensive mRNA and miRNA expression profiles described here provide insight into gene expression regulation that may underlie the adverse effects cigarette smoking has on alveolar macrophages.
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Affiliation(s)
- Joel W. Graff
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Iowa City Veteran Affairs Medical Center, Iowa City, Iowa, United States of America
| | - Linda S. Powers
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Anne M. Dickson
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jongkwang Kim
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Anna C. Reisetter
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ihab H. Hassan
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Karol Kremens
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Thomas J. Gross
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Mary E. Wilson
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Iowa City Veteran Affairs Medical Center, Iowa City, Iowa, United States of America
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Martha M. Monick
- Department of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Philibert RA, Sears RA, Powers LS, Nash E, Bair T, Gerke AK, Hassan I, Thomas CP, Gross TJ, Monick MM. Coordinated DNA methylation and gene expression changes in smoker alveolar macrophages: specific effects on VEGF receptor 1 expression. J Leukoc Biol 2012; 92:621-31. [PMID: 22427682 DOI: 10.1189/jlb.1211632] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cigarette smoking is implicated in numerous diseases, including emphysema and lung cancer. The clinical expression of lung disease in smokers is not well explained by currently defined variations in gene expression or simple differences in smoking exposure. Alveolar macrophages play a critical role in the inflammation and remodeling of the lung parenchyma in smoking-related lung disease. Significant gene expression changes in alveolar macrophages from smokers have been identified. However, the mechanism for these changes remains unknown. One potential mechanism for smoking-altered gene expression is via changes in cytosine methylation in DNA regions proximal to gene-coding sequences. In this study, alveolar macrophage DNA from heavy smokers and never smokers was isolated and methylation status at 25,000 loci determined. We found differential methylation in genes from immune-system and inflammatory pathways. Analysis of matching gene expression data demonstrated a parallel enrichment for changes in immune-system and inflammatory pathways. A significant number of genes with smoking-altered mRNA expression had inverse changes in methylation status. One gene highlighted by this data was the FLT1, and further studies found particular up-regulation of a splice variant encoding a soluble inhibitory form of the receptor. In conclusion, chronic cigarette smoke exposure altered DNA methylation in specific gene promoter regions in human alveolar macrophages.
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Monick MM, Beach SR, Plume J, Sears R, Gerrard M, Brody GH, Philibert RA. Coordinated changes in AHRR methylation in lymphoblasts and pulmonary macrophages from smokers. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:141-51. [PMID: 22232023 PMCID: PMC3318996 DOI: 10.1002/ajmg.b.32021] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 12/21/2011] [Indexed: 12/20/2022]
Abstract
Smoking is associated with a wide variety of adverse health outcomes including cancer, chronic obstructive pulmonary disease, diabetes, depression, and heart disease. Unfortunately, the molecular mechanisms through which these effects are conveyed are not clearly understood. To examine the potential role of epigenetic factors in these processes, we examined the relationship of smoking to genome wide methylation and gene expression using biomaterial from two independent samples, lymphoblast DNA and RNA (n = 119) and lung alveolar macrophage DNA (n = 19). We found that in both samples current smoking status was associated with significant changes in DNA methylation, in particular at the aryl hydrocarbon receptor repressor (AHRR), a known tumor suppressor. Both baseline DNA methylation and smoker associated DNA methylation signatures at AHRR were highly correlated (r = 0.94 and 0.45, respectively). DNA methylation at the most differentially methylated AHRR CpG residue in both samples, cg0557592, was significantly associated with AHRR gene expression. Pathway analysis of lymphoblast data (genes with most significant methylation changes) demonstrated enrichment in protein kinase C pathways and in TGF beta signaling pathways. For alveolar macrophages, pathway analysis demonstrated alterations in inflammation-related processes. We conclude that smoking is associated with functionally significant genome wide changes in DNA methylation in both lymphoblasts and pulmonary macrophages and that further integrated investigations of these epigenetic effects of smoking on carcinogenesis and other related co-morbidities are indicated.
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Affiliation(s)
| | - Steven R.H. Beach
- Neuroscience and Genetics Programs, The University of Iowa, Iowa City, IA, The University of Georgia, Athens, GA
| | - Jeff Plume
- Neuroscience and Genetics Programs, The University of Iowa, Iowa City, IA, The University of Georgia, Athens, GA
| | - Rory Sears
- Department of Medicine, The University of Iowa, Iowa City, IA
| | - Meg Gerrard
- Department of Psychiatry, Dartmouth Medical School, Lebanon, NH
| | - Gene H. Brody
- Neuroscience and Genetics Programs, The University of Iowa, Iowa City, IA, The University of Georgia, Athens, GA
| | - Robert A. Philibert
- Neuroscience and Genetics Programs, The University of Iowa, Iowa City, IA, The University of Georgia, Athens, GA
- Department of Psychiatry, The University of Iowa, Iowa City, IA
- To whom correspondence should be addressed. Rm 2-126 MEB Psychiatry Research/MEB, Iowa City, IA, USA. 52242-1000 TEL 319-353-4986, FAX 301-353-3003,
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Elgort MG, O'Shea JM, Jiang Y, Ayer DE. Transcriptional and Translational Downregulation of Thioredoxin Interacting Protein Is Required for Metabolic Reprogramming during G(1). Genes Cancer 2011; 1:893-907. [PMID: 21779470 DOI: 10.1177/1947601910389604] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/12/2010] [Accepted: 10/16/2010] [Indexed: 12/21/2022] Open
Abstract
Growth factor signaling drives increased glucose uptake and glycolysis-the Warburg effect-that supports macromolecular synthesis necessary for cell growth and proliferation. Thioredoxin interacting protein (TXNIP), a direct and glucose-induced transcriptional target of MondoA, is a potent negative regulator of glucose uptake and utilization. Thus, TXNIP may inhibit cell growth by restricting substrate availability for macromolecular synthesis. To determine TXNIP's contribution to metabolic reprogramming, we examined MondoA and TXNIP as cells exit quiescence and enter G(1). Serum stimulation of quiescent immortal diploid fibroblasts resulted in an acute upregulation of glucose uptake and glycolysis coinciding with downregulation of TXNIP expression. Ectopic expression of either MondoA or TXNIP restricted cell growth by blocking glucose uptake. Mechanistically, Ras-MAPK and PI3K/Akt signaling inhibit TXNIP translation and MondoA-dependent TXNIP transcription, respectively. We propose that the coordinated downregulation of MondoA transcriptional activity at the TXNIP promoter and inhibition of TXNIP translation are key components of metabolic reprogramming required for cells to exit quiescence.
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Affiliation(s)
- Marc G Elgort
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
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Schneider A, Mehmood T, Pannetier S, Hanauer A. Altered ERK/MAPK signaling in the hippocampus of the mrsk2_KO mouse model of Coffin-Lowry syndrome. J Neurochem 2011; 119:447-59. [PMID: 21838783 DOI: 10.1111/j.1471-4159.2011.07423.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Coffin-Lowry syndrome is a syndromic form of mental retardation caused by mutations of the Rps6ka3 gene encoding ribosomal s6 kinase (RSK)2. RSK2 belongs to a family containing four members in mammals: RSK1-4. RSKs are serine/threonine kinases and cytosolic substrates of extracellular signal-regulated kinase (ERK) in the Ras/MAPK signaling pathway. RSK2 is highly expressed in the hippocampus, and mrsk2_KO mice display spatial learning and memory impairment. In the present study, we provide evidence of abnormally increased phosphorylation of ERK1/2 in the hippocampus of mrsk2_KO mice. Further studies based on cultured hippocampal neurons revealed that glutamate activates ERK1/2 and RSKs, and confirmed a stronger activation of ERK1/2 in mrsk2_KO neurons than in WT cells. We, thus, provide further evidence that RSK2 exerts a feedback inhibitory effect on the ERK1/2 pathway. We also observed a transient sequestration of P-ERK1/2 in the cytoplasm upon glutamate stimulation. In addition, the transcription factors cAMP response element binding and Ets LiKe gene1 show over-activation in RSK2-deficient neurons. Finally, c-Fos, Zif268 and Arc were significantly over-expressed in mrsk2_KO neurons upon glutamate stimulation. Importantly, the increased phosphorylation of other RSK family members observed in mutant neurons was unable to compensate for RSK2 deficiency. This aberrant ERK1/2 signaling can influence various neuronal functions, and thus play a significant role in cognitive dysfunction in mrsk2_KO mice and in the Coffin-Lowry syndrome.
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Affiliation(s)
- Anne Schneider
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
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Bewley MA, Pham TK, Marriott HM, Noirel J, Chu HP, Ow SY, Ryazanov AG, Read RC, Whyte MKB, Chain B, Wright PC, Dockrell DH. Proteomic evaluation and validation of cathepsin D regulated proteins in macrophages exposed to Streptococcus pneumoniae. Mol Cell Proteomics 2011; 10:M111.008193. [PMID: 21474794 PMCID: PMC3108842 DOI: 10.1074/mcp.m111.008193] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 04/01/2011] [Indexed: 11/23/2022] Open
Abstract
Macrophages are central effectors of innate immune responses to bacteria. We have investigated how activation of the abundant macrophage lysosomal protease, cathepsin D, regulates the macrophage proteome during killing of Streptococcus pneumoniae. Using the cathepsin D inhibitor pepstatin A, we demonstrate that cathepsin D differentially regulates multiple targets out of 679 proteins identified and quantified by eight-plex isobaric tag for relative and absolute quantitation. Our statistical analysis identified 18 differentially expressed proteins that passed all paired t-tests (α = 0.05). This dataset was enriched for proteins regulating the mitochondrial pathway of apoptosis or inhibiting competing death programs. Five proteins were selected for further analysis. Western blotting, followed by pharmacological inhibition or genetic manipulation of cathepsin D, verified cathepsin D-dependent regulation of these proteins, after exposure to S. pneumoniae. Superoxide dismutase-2 up-regulation was temporally related to increased reactive oxygen species generation. Gelsolin, a known regulator of mitochondrial outer membrane permeabilization, was down-regulated in association with cytochrome c release from mitochondria. Eukaryotic elongation factor (eEF2), a regulator of protein translation, was also down-regulated by cathepsin D. Using absence of the negative regulator of eEF2, eEF2 kinase, we confirm that eEF2 function is required to maintain expression of the anti-apoptotic protein Mcl-1, delaying macrophage apoptosis and confirm using a murine model that maintaining eEF2 function is associated with impaired macrophage apoptosis-associated killing of Streptococcus pneumoniae. These findings demonstrate that cathepsin D regulates multiple proteins controlling the mitochondrial pathway of macrophage apoptosis or competing death processes, facilitating intracellular bacterial killing.
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Affiliation(s)
| | - Trong K. Pham
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
| | | | - Josselin Noirel
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
| | - Hseuh-Ping Chu
- ‖Department of Pharmacology University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Jersey, USA
| | - Saw Y. Ow
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
| | - Alexey G. Ryazanov
- ‖Department of Pharmacology University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Jersey, USA
| | - Robert C. Read
- From the ‡Medical School
- ‡‡Sheffield Teaching Hospitals and
| | | | - Benny Chain
- ¶Division of Infection and Immunity, University College London, London, UK
| | - Phillip C. Wright
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
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Reisetter AC, Stebounova LV, Baltrusaitis J, Powers L, Gupta A, Grassian VH, Monick MM. Induction of inflammasome-dependent pyroptosis by carbon black nanoparticles. J Biol Chem 2011; 286:21844-52. [PMID: 21525001 DOI: 10.1074/jbc.m111.238519] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Inhalation of nanoparticles has been implicated in respiratory morbidity and mortality. In particular, carbon black nanoparticles are found in many different environmental exposures. Macrophages take up inhaled nanoparticles and respond via release of inflammatory mediators and in some cases cell death. Based on new data, we propose that exposure of macrophages (both a macrophage cell line and primary human alveolar macrophages) to carbon black nanoparticles induces pyroptosis, an inflammasome-dependent form of cell death. Exposure of macrophages to carbon black nanoparticles resulted in inflammasome activation as defined by cleavage of caspase 1 to its active form and downstream IL-1β release. The cell death that occurred with carbon black nanoparticle exposure was identified as pyroptosis by the protective effect of a caspase 1 inhibitor and a pyroptosis inhibitor. These data demonstrate that carbon black nanoparticle exposure activates caspase 1, increases IL-1β release after LPS priming, and induces the proinflammatory cell death, pyroptosis. The identification of pyroptosis as a cellular response to carbon nanoparticle exposure is novel and relates to environmental and health impacts of carbon-based particulates.
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Affiliation(s)
- Anna C Reisetter
- Department of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Yang G, Xiao X, Rosen DG, Cheng X, Wu X, Chang B, Liu G, Xue F, Mercado-Uribe I, Chiao P, Du X, Liu J. The biphasic role of NF-kappaB in progression and chemoresistance of ovarian cancer. Clin Cancer Res 2011; 17:2181-94. [PMID: 21339307 DOI: 10.1158/1078-0432.ccr-10-3265] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE NF-κB is a transcription factor known to promote tumorigenesis. However, NF-κB is also known to be proapoptotic and may potentially function as a tumor suppressor, although such a functional role has not been extensively investigated in human cancer. EXPERIMENTAL DESIGN A dominant-negative mutant of IκBα with mutations at S32A and S36A was used to inhibit the function of NF-κB in ovarian cancer cell lines. The transcription ability, tumorigenesis, apoptosis, and drug sensitivity were examined in derivative cell lines in comparison with parental cells. We also analyzed the association of nuclear expression of NF-κB p65 with patient survival in an ovarian cancer tissue array. RESULTS We show that NF-κB functions as a tumor suppressor in four ovarian cancer cell lines, but it functions as an oncogene in their aggressive chemoresistant isogenic variants. NF-κB can exert its proapoptotic or antiapoptotic effect by activating or repressing mitogen-activated protein kinase (MAPK) phosphorylation in parental or aggressive chemoresistant variant cell lines. We also show that the nuclear accumulation of p65 in epithelial cancer tissue is associated with a good response to chemotherapy and can predict longer overall survival for patients with ovarian cancer. CONCLUSIONS Our data provide strong evidence that NF-κB can function as a biphasic regulator, either suppressing or enhancing ovarian cancer growth through the regulation of MAPK and cellular apoptosis.
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Affiliation(s)
- Gong Yang
- Cancer Research Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China
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Phosphorylation of DCC by ERK2 Is Facilitated by Direct Docking of the Receptor P1 Domain to the Kinase. Structure 2010; 18:1502-11. [DOI: 10.1016/j.str.2010.08.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/31/2010] [Accepted: 08/13/2010] [Indexed: 01/26/2023]
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Rastogi R, Du W, Ju D, Pirockinaite G, Liu Y, Nunez G, Samavati L. Dysregulation of p38 and MKP-1 in response to NOD1/TLR4 stimulation in sarcoid bronchoalveolar cells. Am J Respir Crit Care Med 2010; 183:500-10. [PMID: 20851927 DOI: 10.1164/rccm.201005-0792oc] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
RATIONALE Sarcoidosis is a systemic inflammatory disorder characterized by distinct up-regulation of Th1 cytokines, such as tumor necrosis factor (TNF)-α and IL-12. The mechanism underlying this up-regulation remains unclear. Recognition of microbial moieties through Toll-like or Nod-like receptors evokes sequential activation of mitogen-activated protein kinases (MAPKs), which plays a role in Th1-immune response. OBJECTIVES To test the hypothesis that dysregulation in MAPK signaling in response to microbial stimulation is important in mediating Th1 response in sarcoidosis. METHODS Ex vivo cultured bronchoalveolar lavage (BAL) cells isolated from patients with sarcoidosis and control subjects were stimulated with low-dose Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain 1 (NOD1) ligands as a model of microbial stimulation, and MAPK signaling and inflammatory response were analyzed. MEASUREMENTS AND MAIN RESULTS BAL cells from patients with sarcoidosis exhibited higher basal p38 activity, greater p38 phosphorylation, and more robust production of TNF-α and IL-12/IL-23p40 on stimulation with NOD1 and TLR4 agonists than cells isolated from control subjects. In contrast, control BAL cells had greater basal extracellular signal-regulated kinase (ERK) activity and NOD1 and TLR4 agonists preferentially activated the ERK pathway. Inhibition of p38, but not ERK, attenuated production of both IL12/IL23p40 and TNF-α. Interestingly, stimulation of cells from patients with sarcoidosis with either NOD1 or TLR4 ligand failed to induce MAPK phosphatase 1 (MKP-1). Adenovirus-mediated overexpression of MKP-1 attenuated p38 activation and decreased the production of IL12/IL23p40 and TNF-α in sarcoid BAL cells. CONCLUSIONS Our results suggest that enhanced p38 signaling in response to microbial products is caused by abnormal regulation of MKP-1 and contributes to heightened inflammation in sarcoidosis.
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Affiliation(s)
- Ruchi Rastogi
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Wayne State University School of Medicine and Detroit Medical Center, Detroit, Michigan, USA
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Groskreutz DJ, Babor EC, Monick MM, Varga SM, Hunninghake GW. Respiratory syncytial virus limits alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha) phosphorylation to maintain translation and viral replication. J Biol Chem 2010; 285:24023-31. [PMID: 20519500 DOI: 10.1074/jbc.m109.077321] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The impact of respiratory syncytial virus (RSV) on morbidity and mortality is significant in that it causes bronchiolitis in infants, exacerbations in patients with obstructive lung disease, and pneumonia in immunocompromised hosts. RSV activates protein kinase R (PKR), a cellular kinase relevant to limiting viral replication (Groskreutz, D. J., Monick, M. M., Powers, L. S., Yarovinsky, T. O., Look, D. C., and Hunninghake, G. W. (2006) J. Immunol. 176, 1733-1740). It is activated by autophosphorylation, likely triggered by a double-stranded RNA intermediate during replication of the virus. In most instances, ph-PKR targets the alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha) protein via phosphorylation, leading to an inhibition of translation of cellular and viral protein. However, we found that although ph-PKR increases in RSV infection, significant eIF2alpha phosphorylation is not observed, and inhibition of protein translation does not occur. RSV infection attenuates eIF2alpha phosphorylation by favoring phosphatase rather than kinase activity. Although PKR is activated, RSV sequesters PKR away from eIF2alpha by binding of the kinase to the RSV N protein. This occurs in conjunction with an increase in the association of the phosphatase, PP2A, with eIF2alpha following PKR activation. The result is limited phosphorylation of eIF2alpha and continued translation of cellular and viral proteins.
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Affiliation(s)
- Dayna J Groskreutz
- Division of Pulmonary, Critical Care, and Occupational Medicine, University of Iowa Roy J, Iowa City, IA 52242, USA.
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Kilberg MS, Shan J, Su N. ATF4-dependent transcription mediates signaling of amino acid limitation. Trends Endocrinol Metab 2009; 20:436-43. [PMID: 19800252 PMCID: PMC3587693 DOI: 10.1016/j.tem.2009.05.008] [Citation(s) in RCA: 430] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 05/18/2009] [Accepted: 05/19/2009] [Indexed: 01/28/2023]
Abstract
Mammals respond to dietary nutrient fluctuations; for example, deficiency of dietary protein or an imbalance of essential amino acids activates an amino acid response (AAR) signal transduction pathway, consisting of detection of uncharged tRNA by the GCN2 kinase, eIF2alpha phosphorylation and ATF4 expression. In concert with heterodimerization partners, ATF4 activates specific genes via a CCAAT-enhancer binding protein-activating transcription factor response element (CARE). This review outlines the ATF4-dependent transcriptional mechanisms associated with the AAR, focusing on progress during the past 5 years. Recent evidence suggests that maternal nutrient deprivation not only has immediate metabolic effects on the fetus, but also triggers gene expression changes in adulthood, possibly through epigenetic mechanisms. Therefore, understanding the transcriptional programs initiated by amino acid limitation is crucial and timely.
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Affiliation(s)
- Michael S Kilberg
- Department of Biochemistry and Molecular Biology, Box 100245, University of Florida, Gainesville, Florida 32610-0245, USA.
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Cell Defence and Survival. GUIDE TO SIGNAL PATHWAYS IN IMMUNE CELLS 2009. [PMCID: PMC7123614 DOI: 10.1007/978-1-60327-538-5_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Central to immune defence mechanisms is the role of transcription factor nuclear factor kappa B (NF-kB). This is a complex biochemical topic with ever more controls revealed. NF-kB determines the production of proinflammatory cytokines and chemokines. Pharmacologists step in with possible means of control. Other systems involved in defence include the cyclooxygenase 2 (Cox-2) enzyme and perioxisome proliferator-activated receptors. Insulin receptor activation needs to be seen in context. The mTOR system directs uptake of nutrients by cells. mTOR is suppressed by rapamycin, whose usage is now quite considerable in the control of transplant rejection.
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Marques Pereira P, Gruss M, Braun K, Foos N, Pannetier S, Hanauer A. Dopaminergic system dysregulation in themrsk2_KO mouse, an animal model of the Coffin-Lowry syndrome. J Neurochem 2008; 107:1325-34. [DOI: 10.1111/j.1471-4159.2008.05703.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Monick MM, Powers LS, Barrett CW, Hinde S, Ashare A, Groskreutz DJ, Nyunoya T, Coleman M, Spitz DR, Hunninghake GW. Constitutive ERK MAPK activity regulates macrophage ATP production and mitochondrial integrity. THE JOURNAL OF IMMUNOLOGY 2008; 180:7485-96. [PMID: 18490749 DOI: 10.4049/jimmunol.180.11.7485] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A unique feature of human alveolar macrophages is their prolonged survival in the face of a stressful environment. We have shown previously that the ERK MAPK is constitutively active in these cells and is important in prolonging cell survival. This study examines the role of the ERK pathway in maintaining mitochondrial energy production. The data demonstrate that ATP levels in alveolar macrophages depend on intact mitochondria and optimal functioning of the electron transport chain. Significant levels of MEK and ERK localize to the mitochondria and inhibition of ERK activity induces an early and profound depletion in cellular ATP coincident with a loss of mitochondrial transmembrane potential. The effect of ERK suppression on ATP levels was specific, since it did not occur with PI3K/Akt, p38, or JNK suppression. ERK inhibition led to cytosolic release of mitochondrial proteins and caspase activation. Both ERK inhibition and mitochondrial blockers induced loss of plasma membrane permeability and cell death. The cell death induced by ERK inhibition had hallmarks of both apoptotic (caspase activation) and necrotic (ATP loss) cell death. By blocking ERK inhibition-induced reactive oxygen species, caspase activation was prevented, although necrotic pathways continued to induce cell death. This suggests that mitochondrial dysfunction caused by ERK inhibition generates both apoptotic and necrotic cell death-inducing pathways. As a composite, these data demonstrate a novel mitochondrial role for ERK in maintaining mitochondrial membrane potential and ATP production in human alveolar macrophages.
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Affiliation(s)
- Martha M Monick
- Department of Medicine, University of Iowa Carver College of Medicine and Veterans Administration Medical Center, Iowa City, IA 52242, USA.
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41
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Bae HK, Pestka JJ. Deoxynivalenol induces p38 interaction with the ribosome in monocytes and macrophages. Toxicol Sci 2008; 105:59-66. [PMID: 18502741 DOI: 10.1093/toxsci/kfn102] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Trichothecene mycotoxins rapidly induce p38-mediated gene expression and apoptosis in mononuclear phagocytes via a process known as the ribotoxic stress response. We hypothesized that the trichothecene deoxynivalenol (DON) induces interaction of p38 with the ribosome. Two models, U937 human monocytes and RAW 264.7 murine macrophages, were used to test this hypothesis based on their capacity to evoke rapid and robust p38 phosphorylation responses to DON. Following DON treatment of U937 cells, lysates were subjected to sucrose gradient fractionation and the resultant ribosomal fractions probed for p38 by Western blotting. p38 content in fractions containing ribosomal subunits and monosomes (RS + M) increased within 5 min of DON treatment and continued to increase up to 30 min. p38 appeared to be initially interact with the 40S subunit fraction and then subsequently with the 60S unit and monosome fractions. Although p38 phosphorylation was blocked by the inhibitor SB203580, interaction of the kinase with the ribosome was unaffected, suggesting that ribosomal binding and phosphorylation were dissociable events. In RAW 264.7 cells, radiolabeled DON uptake occurred within 15 min and this corresponded to sequential increases nonphosphorylated p38 and phosphorylated p38 in the RS + M fraction. As observed for p38, DON similarly induced both ribosomal interaction with two mitogen-activated protein kinases, c-Jun N-terminal kinase, and extracellular signal-regulated kinase, and their subsequent phosphorylation in RAW 264.7 cells. Taken together, these data suggest that, in mononuclear phagocytes, DON induced p38 mobilization to the ribosome and its subsequent phosphorylation. The ribosome might thus play a central role as a scaffold in the ribotoxic stress response.
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Affiliation(s)
- Hee Kyong Bae
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824, USA
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Schwab M, Reynders V, Loitsch S, Steinhilber D, Schröder O, Stein J. The dietary histone deacetylase inhibitor sulforaphane induces human beta-defensin-2 in intestinal epithelial cells. Immunology 2008; 125:241-51. [PMID: 18373608 DOI: 10.1111/j.1365-2567.2008.02834.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial peptides like human beta-defensin-2 (HBD-2) play an important role in the innate immune system protecting the intestinal mucosa against bacterial invasion. The dietary histone deacetylase (HDAC) inhibitors sulforaphane (SFN) and butyrate have received a great deal of attention because of their ability to simultaneously modulate multiple cellular targets involved in cellular protection. In this study the influence of SFN and butyrate on HBD-2 expression as well as the molecular pathways involved in SFN-mediated induction of HBD-2 were scrutinized. Treatment of Caco-2, HT-29 and SW480 cells with SFN led to a time- and dose-dependent upregulation of HBD-2 mRNA expression as determined by semi-quantitative reverse transcription-polymerase chain reaction. Moreover, HBD-2 protein production increased in response to SFN, measured by enzyme-linked immunosorbent assay. Induction of HBD-2 was also observed in response to butyrate. Immunofluorescence analysis revealed that the protein was localized in the cytosol. Coincubation of SFN with a vitamin D receptor (VDR), or an extracellular-regulated kinase 1/2 or a nuclear factor-kappaB inhibitor all reduced HBD-2 mRNA upregulation. In contrast, transfection of cells with a dominant-negative peroxisome proliferator-activated receptor gamma (PPARgamma) mutant vector to inhibit PPARgamma wild-type action and inhibition of p38 mitogen-activated protein kinase (MAPK) signalling did not affect SFN-mediated upregulation of HBD-2 mRNA. Moreover, SFN induced the expression of VDR, PPARgamma and phosphorylated ERK1/2 but did not affect p38 MAPK activation. The data clearly demonstrate for the first time that the dietary HDAC inhibitor SFN is able to induce antimicrobial peptides in colonocytes. In this process HBD-2 expression is regulated via VDR, mitogen-activated protein kinase kinase/extracellular-regulated kinase and nuclear factor-kappaB signalling.
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Affiliation(s)
- Markus Schwab
- First Department of Medicine-ZAFES, Johann Wolfgang Goethe-University Frankfurt, Germany.
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Thiaville MM, Pan YX, Gjymishka A, Zhong C, Kaufman RJ, Kilberg MS. MEK signaling is required for phosphorylation of eIF2alpha following amino acid limitation of HepG2 human hepatoma cells. J Biol Chem 2008; 283:10848-57. [PMID: 18287093 DOI: 10.1074/jbc.m708320200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mammalian amino acid response (AAR) pathway is up-regulated by protein or amino acid depletion. This pathway involves detection of uncharged tRNA by the GCN2 kinase, phosphorylation of the translation initiation factor eIF2alpha (eukaryotic initiation factor 2alpha), and, through subsequent translational control, enhanced de novo synthesis of the transcription factor ATF4. The present studies demonstrate that inhibition of MEK activation in HepG2 human hepatoma cells by PD98059 or U0126 blocked the increased phosphorylation of eIF2alpha and ATF4 synthesis triggered by amino acid limitation, showing that the AAR requires activation of the MEK-ERK pathway. Inhibitors of the JNK or p38 MAPK pathways were ineffective. Consequently, inhibition of MEK activation blocked transcriptional induction of ATF4 target genes, but the induction was rescued by overexpression of ATF4 protein. Furthermore, the enhanced ERK phosphorylation following amino acid deprivation required GCN2 kinase activity and eIF2alpha phosphorylation. Inhibition of protein phosphatase 1 action on phospho-eIF2alpha by knockdown of GADD34 did not block the sensitivity to PD98059, suggesting that MEK functions to enhance GCN2-dependent eIF2alpha phosphorylation rather than suppressing dephosphorylation. Collectively, these results document a critical interdependence between the MEK-ERK MAPK signaling pathway and the amino acid stress-activated pathway.
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Affiliation(s)
- Michelle M Thiaville
- Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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Lachance C, Thuraisingam T, Garnon J, Roter E, Radzioch D. Posttranscriptional gene expression regulation in CpG-activated macrophages depends on FXR1P RNA-binding protein. ACTA ACUST UNITED AC 2007; 51:422-30. [PMID: 17868361 DOI: 10.1111/j.1574-695x.2007.00317.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An RNA-binding protein (RBP) was recently identified, FXR1P, which regulates tumour necrosis factor (TNF) gene expression at the posttranscriptional level in response to lipopolysaccharide, was recently identified resulting in higher TNF production in macrophages from FXR1 knockout (KO) mice compared with wild-type (WT) macrophages. In this study, the importance of FXR1P in the induction of TNF by toll-like receptor 7 (TLR7) ligand S28463 and TLR9 ligand CpG is evaluated. The results clearly reveal a much higher level of TNF protein expression in FXR1-KO than in WT macrophages following stimulation with CpG but not with S28463. To better understand the molecular mechanism, both the steady-state levels and the stability of TNF mRNA were assessed. It was found that the TNF mRNA steady-state level was more elevated in CpG-stimulated FXR1-KO macrophages, while the stability of TNF mRNA was not affected in CpG-stimulated FXR1-KO macrophages. It was also established that FXR1P is involved in regulating the expression of several other inflammatory cytokines and chemokines. Together, the data clearly demonstrate the importance of FXR1P RBP in the regulation of a wide spectrum of inflammatory genes and suggest an important role of MAP signalling in the response of macrophages to selected TLR ligands, including CpG.
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Affiliation(s)
- Claude Lachance
- McGill Centre for Study of Host Resistance, McGill University Health Center Research Institute, Montreal, QC, Canada
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