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Liu H, Sun Z, Hu L, Yue Z. Genome-wide identification of PIP5K in wheat and its relationship with anther male sterility induced by high temperature. BMC Plant Biol 2021; 21:598. [PMID: 34915841 PMCID: PMC8675513 DOI: 10.1186/s12870-021-03363-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Phosphatidylinositol 4 phosphate 5-kinase (PIP5K) plays a key enzyme role in the inositol signal transduction system and has essential functions in plants in terms of growth, development, and stress responses. However, systematic studies on the wheat PIP5K gene family and its relation to male sterility have not been reported yet. RESULTS Sixty-four TaPIP5K genes were identified. The TaPIP5K genes contained similar gene structures and conserved motifs on the same branches of the evolutionary tree, and their cis-regulatory elements were related to MeJA-responsiveness. Furthermore, 49 pairs of collinearity genes were identified and mainly subjected to purification selection during evolution. Synteny analyses showed that some PIP5K genes in wheat and the other four species shared a relatively conserved evolutionary process. The expression levels of many conservative TaPIP5K genes in HT-ms anthers were significantly lower than that in Normal anthers. In addition, HT-ms anthers have no dehiscence, and levels of OPDA and JA-ILE are significantly lower at the trinucleus stage. CONCLUSION These results indicate that the PIP5K gene family may be associated with male sterility induced by HT, and the reduction of JA-ILE levels and the abnormal levels of these genes expression may be one reason for the HT-ms anthers having no dehiscence, ultimately leading to the abortion of the anthers.
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Affiliation(s)
- Hongzhan Liu
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan Province, P.R. China.
| | - Zhongke Sun
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan Province, P.R. China.
| | - Lizong Hu
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan Province, P.R. China
| | - Zonghao Yue
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan Province, P.R. China
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Dash R, Mitra S, Munni YA, Choi HJ, Ali MC, Barua L, Jang TJ, Moon IS. Computational Insights into the Deleterious Impacts of Missense Variants on N-Acetyl-d-glucosamine Kinase Structure and Function. Int J Mol Sci 2021; 22:8048. [PMID: 34360815 PMCID: PMC8347710 DOI: 10.3390/ijms22158048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 07/05/2021] [Accepted: 07/22/2021] [Indexed: 12/11/2022] Open
Abstract
An enzyme of the mammalian amino-sugar metabolism pathway, N-acetylglucosamine kinase (NAGK), that synthesizes N-acetylglucosamine (GlcNAc)-6-phosphate, is reported to promote dynein functions during mitosis, axonal and dendritic growth, cell migration, and selective autophagy, which all are unrelated to its enzyme activity. As non-enzymatic structural functions can be altered by genetic variation, we made an effort in this study aimed at deciphering the pathological effect of nonsynonymous single-nucleotide polymorphisms (nsSNPs) in NAGK gene. An integrated computational approach, including molecular dynamics (MD) simulation and protein-protein docking simulation, was used to identify the damaging nsSNPs and their detailed structural and functional consequences. The analysis revealed the four most damaging variants (G11R, G32R, G120E, and A156D), which are highly conserved and functional, positioned in both small (G11R and G32R) and large (G120E and A156D) domains of NAGK. G11R is located in the ATP binding region, while variants present in the large domain (G120E and A156D) were found to induce substantial alterations in the structural organizations of both domains, including the ATP and substrate binding sites. Furthermore, all variants were found to reduce binding energy between NAGK and dynein subunit DYNLRB1, as revealed by protein-protein docking and MM-GBSA binding energy calculation supporting their deleteriousness on non-canonical function. We hope these findings will direct future studies to gain more insight into the role of these variants in the loss of NAGK function and their role in neurodevelopmental disorders.
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Affiliation(s)
- Raju Dash
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Korea; (R.D.); (S.M.); (Y.A.M.); (H.J.C.)
| | - Sarmistha Mitra
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Korea; (R.D.); (S.M.); (Y.A.M.); (H.J.C.)
| | - Yeasmin Akter Munni
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Korea; (R.D.); (S.M.); (Y.A.M.); (H.J.C.)
| | - Ho Jin Choi
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Korea; (R.D.); (S.M.); (Y.A.M.); (H.J.C.)
| | - Md. Chayan Ali
- Department of Biotechnology & Genetic Engineering, Faculty of Biological Sciences, Islamic University, Kushtia 7003, Bangladesh;
| | - Largess Barua
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong 4381, Bangladesh;
| | - Tae Jung Jang
- Department of Pathology, Dongguk University College of Medicine, Gyeongju 38066, Korea;
| | - Il Soo Moon
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Korea; (R.D.); (S.M.); (Y.A.M.); (H.J.C.)
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Liu H, Jackson ML, Goudswaard LJ, Moore SF, Hutchinson JL, Hers I. Sphingosine-1-phosphate modulates PAR1-mediated human platelet activation in a concentration-dependent biphasic manner. Sci Rep 2021; 11:15308. [PMID: 34321503 PMCID: PMC8319165 DOI: 10.1038/s41598-021-94052-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/18/2021] [Indexed: 11/08/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is a bioactive signalling sphingolipid that is increased in diseases such as obesity and diabetes. S1P can modulate platelet function, however the direction of effect and S1P receptors (S1PRs) involved are controversial. Here we describe the role of S1P in regulating human platelet function and identify the receptor subtypes responsible for S1P priming. Human platelets were treated with protease-activated receptor 1 (PAR-1)-activating peptide in the presence or absence of S1P, S1PR agonists or antagonists, and sphingosine kinases inhibitors. S1P alone did not induce platelet aggregation but at low concentrations S1P enhanced PAR1-mediated platelet responses, whereas PAR1 responses were inhibited by high concentrations of S1P. This biphasic effect was mimicked by pan-S1PR agonists. Specific agonists revealed that S1PR1 receptor activation has a positive priming effect, S1PR2 and S1PR3 have no effect on platelet function, whereas S1PR4 and S1PR5 receptor activation have an inhibitory effect on PAR-1 mediated platelet function. Although platelets express both sphingosine kinase 1/2, enzymes which phosphorylate sphingosine to produce S1P, only dual and SphK2 inhibition reduced platelet function. These results support a role for SphK2-mediated S1P generation in concentration-dependent positive and negative priming of platelet function, through S1PR1 and S1PR4/5 receptors, respectively.
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Affiliation(s)
- Haonan Liu
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Molly L Jackson
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Lucy J Goudswaard
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
- Population Health Sciences, Oakfield House, University of Bristol, Bristol, BS8 2BN, UK
| | - Samantha F Moore
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - James L Hutchinson
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
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4
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Meserve JH, Nelson JC, Marsden KC, Hsu J, Echeverry FA, Jain RA, Wolman MA, Pereda AE, Granato M. A forward genetic screen identifies Dolk as a regulator of startle magnitude through the potassium channel subunit Kv1.1. PLoS Genet 2021; 17:e1008943. [PMID: 34061829 PMCID: PMC8195410 DOI: 10.1371/journal.pgen.1008943] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 06/11/2021] [Accepted: 05/04/2021] [Indexed: 11/19/2022] Open
Abstract
The acoustic startle response is an evolutionarily conserved avoidance behavior. Disruptions in startle behavior, particularly startle magnitude, are a hallmark of several human neurological disorders. While the neural circuitry underlying startle behavior has been studied extensively, the repertoire of genes and genetic pathways that regulate this locomotor behavior has not been explored using an unbiased genetic approach. To identify such genes, we took advantage of the stereotypic startle behavior in zebrafish larvae and performed a forward genetic screen coupled with whole genome analysis. We uncovered mutations in eight genes critical for startle behavior, including two genes encoding proteins associated with human neurological disorders, Dolichol kinase (Dolk), a broadly expressed regulator of the glycoprotein biosynthesis pathway, and the potassium Shaker-like channel subunit Kv1.1. We demonstrate that Kv1.1 and Dolk play critical roles in the spinal cord to regulate movement magnitude during the startle response and spontaneous swim movements. Moreover, we show that Kv1.1 protein is mislocalized in dolk mutants, suggesting they act in a common genetic pathway. Combined, our results identify a diverse set of eight genes, all associated with human disorders, that regulate zebrafish startle behavior and reveal a previously unappreciated role for Dolk and Kv1.1 in regulating movement magnitude via a common genetic pathway.
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Affiliation(s)
- Joy H. Meserve
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jessica C. Nelson
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kurt C. Marsden
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jerry Hsu
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Fabio A. Echeverry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Roshan A. Jain
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Marc A. Wolman
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Alberto E. Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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5
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Velazquez FN, Zhang L, Viscardi V, Trocchia C, Hannun YA, Obeid LM, Snider AJ. Loss of sphingosine kinase 1 increases lung metastases in the MMTV-PyMT mouse model of breast cancer. PLoS One 2021; 16:e0252311. [PMID: 34043703 PMCID: PMC8158862 DOI: 10.1371/journal.pone.0252311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/13/2021] [Indexed: 12/11/2022] Open
Abstract
Breast cancer is a very heterogeneous disease, and ~30% of breast cancer patients succumb to metastasis, highlighting the need to understand the mechanisms of breast cancer progression in order to identify new molecular targets for treatment. Sphingosine kinase 1 (SK1) has been shown to be upregulated in patients with breast cancer, and several studies have suggested its involvement in breast cancer progression and/or metastasis, mostly based on cell studies. In this work we evaluated the role of SK1 in breast cancer development and metastasis using a transgenic breast cancer model, mouse mammary tumor virus-polyoma middle tumor-antigen (MMTV-PyMT), that closely resembles the characteristics and evolution of human breast cancer. The results show that SK1 deficiency does not alter tumor latency or growth, but significantly increases the number of metastatic lung nodules and the average metastasis size in the lung of MMTV-PyMT mice. Additionally, analysis of Kaplan-Meier plotter of human disease shows that high SK1 mRNA expression can be associated with a better prognosis for breast cancer patients. These results suggest a metastasis-suppressing function for SK1 in the MMTV-PyMT model of breast cancer, and that its role in regulating human breast cancer progression and metastasis may be dependent on the breast cancer type.
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Affiliation(s)
- Fabiola N. Velazquez
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Leiqing Zhang
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Valentina Viscardi
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Carolena Trocchia
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Yusuf A. Hannun
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Lina M. Obeid
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Ashley J. Snider
- Department of Medicine, Stony Brook University, Stony Brook, NY, United States of America
- Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
- Department of Nutritional Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ, United States of America
- * E-mail:
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6
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Magadum A, Singh N, Kurian AA, Sharkar MTK, Sultana N, Chepurko E, Kaur K, Żak MM, Hadas Y, Lebeche D, Sahoo S, Hajjar R, Zangi L. Therapeutic Delivery of Pip4k2c-Modified mRNA Attenuates Cardiac Hypertrophy and Fibrosis in the Failing Heart. Adv Sci (Weinh) 2021; 8:2004661. [PMID: 34026458 PMCID: PMC8132051 DOI: 10.1002/advs.202004661] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Heart failure (HF) remains a major cause of morbidity and mortality worldwide. One of the risk factors for HF is cardiac hypertrophy (CH), which is frequently accompanied by cardiac fibrosis (CF). CH and CF are controlled by master regulators mTORC1 and TGF-β, respectively. Type-2-phosphatidylinositol-5-phosphate-4-kinase-gamma (Pip4k2c) is a known mTORC1 regulator. It is shown that Pip4k2c is significantly downregulated in the hearts of CH and HF patients as compared to non-injured hearts. The role of Pip4k2c in the heart during development and disease is unknown. It is shown that deleting Pip4k2c does not affect normal embryonic cardiac development; however, three weeks after TAC, adult Pip4k2c-/- mice has higher rates of CH, CF, and sudden death than wild-type mice. In a gain-of-function study using a TAC mouse model, Pip4k2c is transiently upregulated using a modified mRNA (modRNA) gene delivery platform, which significantly improve heart function, reverse CH and CF, and lead to increased survival. Mechanistically, it is shown that Pip4k2c inhibits TGFβ1 via its N-terminal motif, Pip5k1α, phospho-AKT 1/2/3, and phospho-Smad3. In sum, loss-and-gain-of-function studies in a TAC mouse model are used to identify Pip4k2c as a potential therapeutic target for CF, CH, and HF, for which modRNA is a highly translatable gene therapy approach.
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Affiliation(s)
- Ajit Magadum
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Neha Singh
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Ann Anu Kurian
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Mohammad Tofael Kabir Sharkar
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Nishat Sultana
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Elena Chepurko
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Keerat Kaur
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Magdalena M. Żak
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Yoav Hadas
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Djamel Lebeche
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Susmita Sahoo
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
| | - Roger Hajjar
- Phospholamban FoundationAmsterdamThe Netherlands
| | - Lior Zangi
- Cardiovascular Research CenterIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
- Black Family Stem Cell InstituteIcahn School of Medicine at Mount SinaiNew YorkNY10029USA
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7
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Trayssac M, Clarke CJ, Stith JL, Snider JM, Newen N, Gault CR, Hannun YA, Obeid LM. Targeting sphingosine kinase 1 (SK1) enhances oncogene-induced senescence through ceramide synthase 2 (CerS2)-mediated generation of very-long-chain ceramides. Cell Death Dis 2021; 12:27. [PMID: 33414460 PMCID: PMC7790826 DOI: 10.1038/s41419-020-03281-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 02/06/2023]
Abstract
Senescence is an antiproliferative mechanism that can suppress tumor development and can be induced by oncogenes such as genes of the Ras family. Although studies have implicated bioactive sphingolipids (SL) in senescence, the specific mechanisms remain unclear. Here, using MCF10A mammary epithelial cells, we demonstrate that oncogenic K-Ras (Kirsten rat sarcoma viral oncogene homolog) is sufficient to induce cell transformation as well as cell senescence-as revealed by increases in the percentage of cells in the G1 phase of the cell cycle, p21WAF1/Cip1/CDKN1A (p21) expression, and senescence-associated β-galactosidase activity (SA-β-gal). Furthermore, oncogenic K-Ras altered SL metabolism, with an increase of long-chain (LC) C18, C20 ceramides (Cer), and very-long-chain (VLC) C22:1, C24 Cer, and an increase of sphingosine kinase 1 (SK1) expression. Since Cer and sphingosine-1-phosphate have been shown to exert opposite effects on cellular senescence, we hypothesized that targeting SK1 could enhance oncogenic K-Ras-induced senescence. Indeed, SK1 downregulation or inhibition enhanced p21 expression and SA-β-gal in cells expressing oncogenic K-Ras and impeded cell growth. Moreover, SK1 knockdown further increased LC and VLC Cer species (C18, C20, C22:1, C24, C24:1, C26:1), especially the ones increased by oncogenic K-Ras. Fumonisin B1 (FB1), an inhibitor of ceramide synthases (CerS), reduced p21 expression induced by oncogenic K-Ras both with and without SK1 knockdown. Functionally, FB1 reversed the growth defect induced by oncogenic K-Ras, confirming the importance of Cer generation in the senescent phenotype. More specifically, downregulation of CerS2 by siRNA blocked the increase of VLC Cer (C24, C24:1, and C26:1) induced by SK1 knockdown and phenocopied the effects of FB1 on p21 expression. Taken together, these data show that targeting SK1 is a potential therapeutic strategy in cancer, enhancing oncogene-induced senescence through an increase of VLC Cer downstream of CerS2.
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Affiliation(s)
- Magali Trayssac
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
| | - Christopher J Clarke
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA.
- Stony Brook Cancer Center, Stony Brook, NY, USA.
| | - Jeffrey L Stith
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
| | - Justin M Snider
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
| | - Naomi Newen
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
| | | | - Yusuf A Hannun
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA.
- Stony Brook Cancer Center, Stony Brook, NY, USA.
| | - Lina M Obeid
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
- Northport Veterans Affairs Medical Center, Northport, NY, USA
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8
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Chua XY, Ho LTY, Xiang P, Chew WS, Lam BWS, Chen CP, Ong WY, Lai MKP, Herr DR. Preclinical and Clinical Evidence for the Involvement of Sphingosine 1-Phosphate Signaling in the Pathophysiology of Vascular Cognitive Impairment. Neuromolecular Med 2020; 23:47-67. [PMID: 33180310 DOI: 10.1007/s12017-020-08632-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023]
Abstract
Sphingosine 1-phosphates (S1Ps) are bioactive lipids that mediate a diverse range of effects through the activation of cognate receptors, S1P1-S1P5. Scrutiny of S1P-regulated pathways over the past three decades has identified important and occasionally counteracting functions in the brain and cerebrovascular system. For example, while S1P1 and S1P3 mediate proinflammatory effects on glial cells and directly promote endothelial cell barrier integrity, S1P2 is anti-inflammatory but disrupts barrier integrity. Cumulatively, there is significant preclinical evidence implicating critical roles for this pathway in regulating processes that drive cerebrovascular disease and vascular dementia, both being part of the continuum of vascular cognitive impairment (VCI). This is supported by clinical studies that have identified correlations between alterations of S1P and cognitive deficits. We review studies which proposed and evaluated potential mechanisms by which such alterations contribute to pathological S1P signaling that leads to VCI-associated chronic neuroinflammation and neurodegeneration. Notably, S1P receptors have divergent but overlapping expression patterns and demonstrate complex interactions. Therefore, the net effect produced by S1P represents the cumulative contributions of S1P receptors acting additively, synergistically, or antagonistically on the neural, vascular, and immune cells of the brain. Ultimately, an optimized therapeutic strategy that targets S1P signaling will have to consider these complex interactions.
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Affiliation(s)
- Xin Ying Chua
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Leona T Y Ho
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore
| | - Ping Xiang
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Wee Siong Chew
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Brenda Wan Shing Lam
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Christopher P Chen
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Memory Aging and Cognition Centre, National University Health System, Kent Ridge, Singapore
| | - Wei-Yi Ong
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore
- Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, 119260, Singapore
| | - Mitchell K P Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Memory Aging and Cognition Centre, National University Health System, Kent Ridge, Singapore.
| | - Deron R Herr
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Department of Biology, San Diego State University, San Diego, CA, USA.
- American University of Health Sciences, Long Beach, CA, USA.
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Park SB, Choi BI, Lee BJ, Kim NJ, Jeong YA, Joo MK, Kim HJ, Park JJ, Kim JS, Noh YS, Lee HJ. Intestinal Epithelial Deletion of Sphk1 Prevents Colitis-Associated Cancer Development by Inhibition of Epithelial STAT3 Activation. Dig Dis Sci 2020; 65:2284-2293. [PMID: 31776862 DOI: 10.1007/s10620-019-05971-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 11/16/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND AND AIMS Colitis-associated cancer (CAC) is one of the most serious complications in patients with inflammatory bowel disease. Sphingosine kinase 1 (Sphk1) is a key enzyme in the sphingolipid pathway and has oncogene potential for inducing both initiation and progression of tumors. The aim of this work is to characterize the role of epithelial Sphk1 in mouse colitis and CAC models. METHODS We investigated the roles of Sphk1 in CAC by conditional deletion of Sphk1 in intestinal epithelial cells (IECs). RESULTS CAC was induced in both Sphk1ΔIEC/ApcMin/+ and Sphk1IEC/ApcMin/+ mice by administration of 2% dextran sodium sulfate (DSS) for 7 days. Genetic deletion of Sphk1 significantly reduced the number and size of tumors in ApcMin/+ mice. Histologic grade was more severe in Sphk1ΔIEC/ApcMin/+ mice compared with Sphk1IEC/ApcMin/+ mice (invasive carcinoma, 71% versus 13%, p < 0.05). Deletion of Sphk1 decreased mucosal proliferation and inhibited STAT3 activation and genetic expression of cyclin D1 and cMyc in tumor cells. Conditional deletion of Sphk1 using CRISPR-Cas9 in HCT 116 cells inhibited interleukin (IL)-6-mediated STAT3 activation. CONCLUSIONS Epithelial conditional deletion of Sphk1 inhibits CAC in ApcMin/+-DSS models in mice by inhibiting STAT3 activation and its target signaling pathways.
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Affiliation(s)
- Seung Bin Park
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Byung-Il Choi
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Beom Jae Lee
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea.
| | - Nam Joo Kim
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Yoon A Jeong
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Moon Kyung Joo
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Hyo Jung Kim
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Jong-Jae Park
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Jae Seon Kim
- Division of Gastroenterology, Department of Internal Medicine, Korea University Guro Hospital, College of Medicine, Korea University, 80, Guro-dong, Guro-gu, Seoul, Korea
| | - Yoon-Seok Noh
- College of Pharmacy, Chungbuk National University, Cheongju, Korea
| | - Hyun Joo Lee
- Department of Pathology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
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10
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Strunk BS, Steinfeld N, Lee S, Jin N, Muñoz-Rivera C, Meeks G, Thomas A, Akemann C, Mapp AK, MacGurn JA, Weisman LS. Roles for a lipid phosphatase in the activation of its opposing lipid kinase. Mol Biol Cell 2020; 31:1835-1845. [PMID: 32583743 PMCID: PMC7525815 DOI: 10.1091/mbc.e18-09-0556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Fig4 is a phosphoinositide phosphatase that converts PI3,5P2 to PI3P. Paradoxically, mutation of Fig4 results in lower PI3,5P2, indicating that Fig4 is also required for PI3,5P2 production. Fig4 promotes elevation of PI3,5P2, in part, through stabilization of a protein complex that includes its opposing lipid kinase, Fab1, and the scaffold protein Vac14. Here we show that multiple regions of Fig4 contribute to its roles in the elevation of PI3,5P2: its catalytic site, an N-terminal disease-related surface, and a C-terminal region. We show that mutation of the Fig4 catalytic site enhances the formation of the Fab1-Vac14-Fig4 complex, and reduces the ability to elevate PI3,5P2. This suggests that independent of its lipid phosphatase function, the active site plays a role in the Fab1-Vac14-Fig4 complex. We also show that the N-terminal disease-related surface contributes to the elevation of PI3,5P2 and promotes Fig4 association with Vac14 in a manner that requires the Fig4 C-terminus. We find that the Fig4 C-terminus alone interacts with Vac14 in vivo and retains some functions of full-length Fig4. Thus, a subset of Fig4 functions are independent of its phosphatase domain and at least three regions of Fig4 play roles in the function of the Fab1-Vac14-Fig4 complex.
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Affiliation(s)
- Bethany S Strunk
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
- Department of Biology, Trinity University, San Antonio, TX 78212
| | - Noah Steinfeld
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109
| | - Sora Lee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Natsuko Jin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | | | - Garrison Meeks
- Department of Biology, Trinity University, San Antonio, TX 78212
| | - Asha Thomas
- Department of Biology, Trinity University, San Antonio, TX 78212
| | - Camille Akemann
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Anna K Mapp
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109
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11
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Lee S, Beon J, Kim MG, Kim S. Inositol polyphosphate multikinase in adipocytes is dispensable for regulating energy metabolism and whole body metabolic homeostasis. Am J Physiol Endocrinol Metab 2020; 319:E401-E409. [PMID: 32634320 DOI: 10.1152/ajpendo.00030.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Adipose tissue plays a central role in regulating whole body energy and glucose homeostasis at both organ and systemic levels. Inositol polyphosphates, such as 5-diphosphoinositol pentakisphosphate, reportedly control adipocyte functions and energy expenditure. However, the physiological roles of the inositol polyphosphate (IP) pathway in the adipose tissue are not yet fully defined. The aim of the present study was to test the hypothesis that inositol polyphosphate multikinase (IPMK), a key enzyme in the IP metabolism, plays a critical role in adipose tissue biology and obesity. We generated adipocyte-specific IPMK knockout (Ipmk AKO) mice and evaluated metabolic phenotypes by measuring fat accumulation, glucose homeostasis, and insulin sensitivity in adult mice fed either a regular-chow diet or high-fat diet (HFD). Despite substantial reduction of IPMK, Ipmk AKO mice exhibited normal glucose tolerance and insulin sensitivity and did not show changes in fat accumulation in response to HFD-feeding. In addition, loss of IPMK had no major impact on thermogenic processes in response to cold exposure. Collectively, these findings suggest that adipocyte IPMK is dispensable for normal adipose tissue and its physiological functions in whole body metabolism, suggesting the complex roles that inositol polyphosphate metabolism has in the regulation of adipose tissue.
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Affiliation(s)
- Seulgi Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Jiyoon Beon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Min-Gyu Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Seyun Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
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12
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Syed SN, Weigert A, Brüne B. Sphingosine Kinases are Involved in Macrophage NLRP3 Inflammasome Transcriptional Induction. Int J Mol Sci 2020; 21:ijms21134733. [PMID: 32630814 PMCID: PMC7370080 DOI: 10.3390/ijms21134733] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/20/2022] Open
Abstract
Recent studies suggested an important contribution of sphingosine-1-phospate (S1P) signaling via its specific receptors (S1PRs) in the production of pro-inflammatory mediators such as Interleukin (IL)-1β in cancer and inflammation. In an inflammation-driven cancer setting, we previously reported that myeloid S1PR1 signaling induces IL-1β production by enhancing NLRP3 (NOD-, LRR- and Pyrin Domain-Containing Protein 3) inflammasome activity. However, the autocrine role of S1P and enzymes acting on the S1P rheostat in myeloid cells are unknown. Using human and mouse macrophages with pharmacological or genetic intervention we explored the relative contribution of sphingosine kinases (SPHKs) in NLRP3 inflammasome activity regulation. We noticed redundancy in SPHK1 and SPHK2 activities towards macrophage NLRP3 inflammasome transcriptional induction and IL-1β secretion. However, pharmacological blockade of both kinases in unison completely abrogated NLRP3 inflammasome induction and IL-1β secretion. Interestingly, human and mouse macrophages demonstrate varied responses towards SPHKs inhibition and IL-1β secretion. Clinical datasets of renal cell carcinoma and psoriasis patients showed a positive correlation between enzymes affecting the S1P rheostat with NLRP3 inflammasome components expression, which corroborates our finding. Our data provide a better understanding on the role of SPHKs and de novo synthesized S1P in macrophage NLRP3 inflammasome activation.
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Affiliation(s)
- Shahzad Nawaz Syed
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany; (S.N.S.); (A.W.)
| | - Andreas Weigert
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany; (S.N.S.); (A.W.)
| | - Bernhard Brüne
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany; (S.N.S.); (A.W.)
- Project Group Translational Medicine and Pharmacology TMP, Fraunhofer Institute for Molecular Biology and Applied Ecology, 60596 Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, 60590 Frankfurt, Germany
- Frankfurt Cancer Institute, Goethe-University Frankfurt, 60596 Frankfurt, Germany
- Correspondence: ; Tel.: +49-69-6301-7424
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13
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Gupta P, Mohammad T, Dahiya R, Roy S, Noman OMA, Alajmi MF, Hussain A, Hassan MI. Evaluation of binding and inhibition mechanism of dietary phytochemicals with sphingosine kinase 1: Towards targeted anticancer therapy. Sci Rep 2019; 9:18727. [PMID: 31822735 PMCID: PMC6904568 DOI: 10.1038/s41598-019-55199-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
Sphingosine kinase 1 (SphK1) has recently gained attention as a potential drug target for its association with cancer and other inflammatory diseases. Here, we have investigated the binding affinity of dietary phytochemicals viz., ursolic acid, capsaicin, DL-α tocopherol acetate, quercetin, vanillin, citral, limonin and simvastatin with the SphK1. Docking studies revealed that all these compounds bind to the SphK1 with varying affinities. Fluorescence binding and isothermal titration calorimetric measurements suggested that quercetin and capsaicin bind to SphK1 with an excellent affinity, and significantly inhibits its activity with an admirable IC50 values. The binding mechanism of quercetin was assessed by docking and molecular dynamics simulation studies for 100 ns in detail. We found that quercetin acts as a lipid substrate competitive inhibitor, and it interacts with important residues of active-site pocket through hydrogen bonds and other non-covalent interactions. Quercetin forms a stable complex with SphK1 without inducing any significant conformational changes in the protein structure. In conclusion, we infer that quercetin and capsaicin provide a chemical scaffold to develop potent and selective inhibitors of SphK1 after required modifications for the clinical management of cancer.
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Affiliation(s)
- Preeti Gupta
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Rashmi Dahiya
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Sonam Roy
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Omar Mohammed Ali Noman
- Department of Pharmacognosy College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Mohamed F Alajmi
- Department of Pharmacognosy College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia.
| | - Afzal Hussain
- Department of Pharmacognosy College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India.
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14
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Han C, He X, Xia X, Guo J, Liu A, Liu X, Wang X, Li C, Peng S, Zhao W, Zhou M, Shi X, Li Y, Li Y, Shan Z, Teng W. Sphk1/S1P/S1PR1 Signaling is Involved in the Development of Autoimmune Thyroiditis in Patients and NOD.H-2 h4 Mice. Thyroid 2019; 29:700-713. [PMID: 30963819 DOI: 10.1089/thy.2018.0065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background: There is growing evidence that sphingosine-1-phosphate (S1P), a pleiotropic bioactive sphingolipid metabolite synthesized intracellularly by two closely related sphingosine kinases (SphKs), SphK1 and SphK2, is involved in inflammation. However, the role of SphKs/S1P/S1P receptors (S1PRs) in autoimmune thyroiditis (AIT) has not been studied to date. Methods: This study examined whether SphK1/S1P/S1PR1 signaling is aberrantly altered in thyroid tissues and serum of both AIT patients and a spontaneously autoimmune thyroiditis (SAT) mouse model. Murine CD4+T cells were employed to further investigate the downstream signaling of SphK1/S1P/S1PR1. Furthermore, a total of 102 NOD.H-2h4 mice, randomly divided into different groups, were used to investigate the therapeutic effect of S1PR1 blockade and its potential mechanism. Results: We found that components of the SphK1/S1P/S1PR1 pathway were abnormally expressed in patients with Hashimoto thyroiditis and in a SAT mouse model. In addition, S1P could activate signal transducer and activator of transcription 3 (STAT3) through S1PR1 and its downstream signaling pathways in CD4+T cells of NOD.H-2h4 mice. Furthermore, an in vivo study demonstrated that blocking S1PR1 by FTY720 administration could reduce the incidence and severity of thyroiditis and goiter in SAT mice in a time-dependent manner. The proportions of STAT3-related and inflammation-related cell subtypes, such as T helper 1, T helper 17, and follicular T helper cells, were elevated in the SAT group when compared to the control group, and these cell subtypes decreased after FTY720 administration. Furthermore, the downstream inflammatory cytokines of STAT3 were also downregulated after FTY720 administration. Conclusion: The present study shows that blocking Sphk1/S1P/S1PR1 signaling can ameliorate the severity of AIT, providing evidence of a promising therapeutic target for AIT.
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Affiliation(s)
- Cheng Han
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
- 2 Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York
| | - Xue He
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xinghai Xia
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
- 3 Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Jiahui Guo
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Aihua Liu
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xin Liu
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xinyi Wang
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Chengyan Li
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Shiqiao Peng
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Wei Zhao
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
- 4 Department of Endocrinology, Dalian Municipal Central Hospital Affiliated of Dalian Medical University, Dalian, China
| | - Mi Zhou
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
- 3 Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Xiaoguang Shi
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yushu Li
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yongze Li
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Zhongyan Shan
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Weiping Teng
- 1 Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Affiliated Hospital of China Medical University, Shenyang, China
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15
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Keeley T, Lin S, Lester DK, Lau EK, Yang S. The fucose salvage pathway inhibits invadopodia formation and extracellular matrix degradation in melanoma cells. PLoS One 2018; 13:e0199128. [PMID: 29924834 PMCID: PMC6010265 DOI: 10.1371/journal.pone.0199128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/03/2018] [Indexed: 12/02/2022] Open
Abstract
The fucose salvage pathway is a two-step process in which mammalian cells transform L-fucose into GDP-L-fucose, a universal fucose donor used by fucosyltransferases to modify glycans. Emerging evidence indicates the fucose salvage pathway and the fucosylation of proteins are altered during melanoma progression and metastasis. However the underlying mechanisms are not completely understood. Here, we report that the fucose salvage pathway inhibits invadopodia formation and extracellular matrix degradation by promoting α-1,2 fucosylation. Chemically or genetically increasing the fucose salvage pathway decreases invadopodium numbers and inhibits the proteolytic activity of invadopodia in WM793 melanoma cells. Inhibiting fucosylation by depleting fucokinase abrogates L-fucose-mediated inhibition of invadopodia, suggesting dependence on the fucose salvage pathway. The inhibition of invadopodium formation by L-fucose or ectopically expressed FUK could be rescued by treatment with α-1,2, but not α-1,3/α-1,4 fucosidase, implicating an α-1,2 fucose linkage-dependent anti-metastatic effect. The expression of FUT1, an α-1,2 fucosyltransferase, is remarkably down-regulated during melanoma progression, and the ectopic expression of FUT1 is sufficient to inhibit invadopodium formation and ECM degradation. Our findings indicate that the fucose salvage pathway can inhibit invadopodium formation, and consequently, invasiveness in melanoma via α-1,2 fucosylation. Re-activation of this pathway in melanoma could be useful for preventing melanoma invasion and metastasis.
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Affiliation(s)
- Tyler Keeley
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
- University of South Florida Cancer Biology Graduate Program, Tampa, Florida, United States of America
| | - Shengchen Lin
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
| | - Daniel K. Lester
- University of South Florida Cancer Biology Graduate Program, Tampa, Florida, United States of America
- Department of Tumor Biology, Comprehensive Melanoma Research Center, H. Lee Moffitt Cancer Center, Tampa, Florida, United States of America
| | - Eric K. Lau
- Department of Tumor Biology, Comprehensive Melanoma Research Center, H. Lee Moffitt Cancer Center, Tampa, Florida, United States of America
| | - Shengyu Yang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
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16
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Ghosh M, Thangada S, Dasgupta O, Khanna KM, Yamase HT, Kashgarian M, Hla T, Shapiro LH, Ferrer FA. Cell-intrinsic sphingosine kinase 2 promotes macrophage polarization and renal inflammation in response to unilateral ureteral obstruction. PLoS One 2018. [PMID: 29518138 PMCID: PMC5843290 DOI: 10.1371/journal.pone.0194053] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sphingosine Kinase-2 (Sphk2) is responsible for the production of the bioactive lipid Sphingosine-1 Phosphate, a key regulator of tissue repair. Here we address the in vivo significance of Sphingosine Kinase -2 in renal inflammation/fibrosis in response to unilateral ureteral obstruction using both genetic and pharmacological strategies. Obstructed kidneys of Sphk2-/- mice showed reduced renal damage and diminished levels of the renal injury markers TGFβ1 and αSMA when compared to wild type controls. We found a consistently significant increase in anti-inflammatory (M2) macrophages in obstructed Sphk2-/- kidneys by flow cytometry and a decrease in mRNA levels of the inflammatory cytokines, MCP1, TNFα, CXCL1 and ILβ1, suggesting an anti-inflammatory bias in the absence of Sphk2. Indeed, metabolic profiling showed that the pro-inflammatory glycolytic pathway is largely inactive in Sphk2-/- bone marrow-derived macrophages. Furthermore, treatment with the M2-promoting cytokines IL-4 or IL-13 demonstrated that macrophages lacking Sphk2 polarized more efficiently to the M2 phenotype than wild type cells. Bone marrow transplant studies indicated that expression of Sphk2-/- on either the hematopoietic or parenchymal cells did not fully rescue the pro-healing phenotype, confirming that both infiltrating M2-macrophages and the kidney microenvironment contribute to the damaging Sphk2 effects. Importantly, obstructed kidneys from mice treated with an Sphk2 inhibitor recapitulated findings in the genetic model. These results demonstrate that reducing Sphk2 activity by genetic or pharmacological manipulation markedly decreases inflammatory and fibrotic responses to obstruction, resulting in diminished renal injury and supporting Sphk2 as a novel driver of the pro-inflammatory macrophage phenotype.
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Affiliation(s)
- Mallika Ghosh
- Center for Vascular Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- Department of Cell Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
| | - Shobha Thangada
- Center for Vascular Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- Department of Cell Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
| | - Oisharya Dasgupta
- Center for Vascular Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- Department of Cell Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
| | - Kamal M. Khanna
- Department of Immunology, University of Connecticut School of Medicine, Farmington, CT, United States of America
| | - Harold T. Yamase
- Department of Pathology, University of Connecticut School of Medicine, Farmington, CT, United States of America
| | - Michael Kashgarian
- Department of Pathology, Yale University Cancer Research Center, New Haven, CT, United States of America
| | - Timothy Hla
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States of America
| | - Linda H. Shapiro
- Center for Vascular Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- Department of Cell Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- * E-mail: (FAF); (LHS)
| | - Fernando A. Ferrer
- Center for Vascular Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- Department of Cell Biology, University of Connecticut School of Medicine, Farmington, CT, United States of America
- Section of Pediatric Urology, Children's Hospital of Omaha, Department of Surgery, University of Nebraska School of Medicine, Omaha, NE, United States of America
- * E-mail: (FAF); (LHS)
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17
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Abstract
Notch signaling is an evolutionarily conserved pathway that is essential for development, where it controls processes ranging from cell differentiation to survival. Transport through endosomes is a critical step in regulating Notch signaling capacity, where the E3 ubiquitin ligase DTX1 is thought to control Notch1 intracellular transport decisions by direct receptor ubiquitination. However, how DTX1 regulates Notch1 transport within endosomes and the consequence of Notch1 ubiquitination by DTX1 remain unresolved. Here we demonstrate that DTX1 colocalizes with Notch1 on tubulovesicular recycling endosomes. We find that DTX1 silencing leads to enhanced Notch1 recycling from this compartment to the cell surface via a rab4a-mediated transport route. This, in turn, increases Notch1 cell-surface levels and enhances signaling. Surprisingly, we discovered that DTX1 depletion also elevates Notch1 activity mediated by a mutant form of the receptor that lacks lysine residues for ubiquitination, suggesting that DTX1 targets additional factors. Using an activity-based screen for ubiquitination targets, we identified multiple DTX1 substrates including PI5P4Kγ, a lipid kinase involved in PI(4,5)P2 production. Immunolocalization analysis reveals that PI5P4Kγ, like DTX1 and Notch1, is present on tubulovesicular recycling endosomes. However, in contrast to DTX1, Notch1 signaling is inhibited by pharmacological inactivation or siRNA depletion of PI5P4Kγ. Moreover, loss of PI5P4Kγ activity decreases Notch1 recycling rates and reduces receptor cell-surface levels. Collectively, these findings argue that PI5P4Kγ positively regulates the Notch pathway by promoting receptor recycling. Additionally, they support a model where DTX1 controls Notch1 endosomal sorting decisions by controlling PI5P4Kγ-mediated production of PI(4,5)P2.
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Affiliation(s)
- Li Zheng
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Twin Cities, Minneapolis, MN 55455
| | - Sean D Conner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Twin Cities, Minneapolis, MN 55455
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18
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Sukocheva OA. Expansion of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor Function in Normal and Cancer Cells: From Membrane Restructuring to Mediation of Estrogen Signaling and Stem Cell Programming. Int J Mol Sci 2018; 19:ijms19020420. [PMID: 29385066 PMCID: PMC5855642 DOI: 10.3390/ijms19020420] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/21/2018] [Accepted: 01/24/2018] [Indexed: 02/05/2023] Open
Abstract
Sphingolipids, sphingolipid metabolizing enzymes, and their receptors network are being recognized as part of the signaling mechanisms, which govern breast cancer cell growth, migration, and survival during chemotherapy treatment. Approximately 70% of breast cancers are estrogen receptor (ER) positive and, thus, rely on estrogen signaling. Estrogen activates an intracellular network composed of many cytoplasmic and nuclear mediators. Some estrogen effects can be mediated by sphingolipids. Estrogen activates sphingosine kinase 1 (SphK1) and amplifies the intracellular concentration of sphingosine-1-phosphate (S1P) in breast cancer cells during stimulation of proliferation and survival. Specifically, Estrogen activates S1P receptors (S1PR) and induces growth factor receptor transactivation. SphK, S1P, and S1PR expression are causally associated with endocrine resistance and progression to advanced tumor stages in ER-positive breast cancers in vivo. Recently, the network of SphK/S1PR was shown to promote the development of ER-negative cancers and breast cancer stem cells, as well as stimulating angiogenesis. Novel findings confirm and broaden our knowledge about the cross-talk between sphingolipids and estrogen network in normal and malignant cells. Current S1PRs therapeutic inhibition was indicated as a promising chemotherapy approach in non-responsive and advanced malignancies. Considering that sphingolipid signaling has a prominent role in terminally differentiated cells, the impact should be considered when designing specific SphK/S1PR inhibitors. This study analyzes the dynamic of the transformation of sphingolipid axis during a transition from normal to pathological condition on the level of the whole organism. The sphingolipid-based mediation and facilitation of global effects of estrogen were critically accented as a bridging mechanism that should be explored in cancer prevention.
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Affiliation(s)
- Olga A Sukocheva
- College of Nursing and Health Sciences, Flinders University of South Australia, Bedford Park, SA 5042, Australia.
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19
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Al-Shujairi WH, Clarke JN, Davies LT, Alsharifi M, Pitson SM, Carr JM. Intracranial Injection of Dengue Virus Induces Interferon Stimulated Genes and CD8+ T Cell Infiltration by Sphingosine Kinase 1 Independent Pathways. PLoS One 2017; 12:e0169814. [PMID: 28095439 PMCID: PMC5240945 DOI: 10.1371/journal.pone.0169814] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/21/2016] [Indexed: 02/05/2023] Open
Abstract
We have previously reported that the absence of sphingosine kinase 1 (SK1) affects both dengue virus (DENV) infection and innate immune responses in vitro. Here we aimed to define SK1-dependancy of DENV-induced disease and the associated innate responses in vivo. The lack of a reliable mouse model with a fully competent interferon response for DENV infection is a challenge, and here we use an experimental model of DENV infection in the brain of immunocompetent mice. Intracranial injection of DENV-2 into C57BL/6 mice induced body weight loss and neurological symptoms which was associated with a high level of DENV RNA in the brain. Body weight loss and DENV RNA level tended to be greater in SK1-/- compared with wildtype (WT) mice. Brain infection with DENV-2 is associated with the induction of interferon-β (IFN-β) and IFN-stimulated gene (ISG) expression including viperin, Ifi27l2a, IRF7, and CXCL10 without any significant differences between WT and SK1-/- mice. The SK2 and sphingosine-1-phosphate (S1P) levels in the brain were unchanged by DENV infection or the lack of SK1. Histological analysis demonstrated the presence of a cellular infiltrate in DENV-infected brain with a significant increase in mRNA for CD8 but not CD4 suggesting this infiltrate is likely CD8+ but not CD4+ T-lymphocytes. This increase in T-cell infiltration was not affected by the lack of SK1. Overall, DENV-infection in the brain induces IFN and T-cell responses but does not influence the SK/S1P axis. In contrast to our observations in vitro, SK1 has no major influence on these responses following DENV-infection in the mouse brain.
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Affiliation(s)
- Wisam H. Al-Shujairi
- Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, South Australia, Australia
- * E-mail:
| | - Jennifer N. Clarke
- Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, South Australia, Australia
| | - Lorena T. Davies
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Mohammed Alsharifi
- Vaccine Research Laboratory, Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Stuart M. Pitson
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Jillian M. Carr
- Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, South Australia, Australia
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20
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Islam MA, Sharif SR, Lee H, Moon IS. N-Acetyl-D-Glucosamine Kinase Promotes the Axonal Growth of Developing Neurons. Mol Cells 2015; 38:876-85. [PMID: 26467288 PMCID: PMC4625069 DOI: 10.14348/molcells.2015.0120] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/03/2015] [Accepted: 08/05/2015] [Indexed: 01/01/2023] Open
Abstract
N-acetyl-D-glucosamine kinase (NAGK) plays an enzyme activity-independent, non-canonical role in the dendritogenesis of hippocampal neurons in culture. In this study, we investigated its role in axonal development. We found NAGK was distributed throughout neurons until developmental stage 3 (axonal outgrowth), and that its axonal expression remarkably decreased during stage 4 (dendritic outgrowth) and became negligible in stage 5 (mature). Immunocytochemistry (ICC) showed colocalization of NAGK with tubulin in hippocampal neurons and with Golgi in somata, dendrites, and nascent axons. A proximity ligation assay (PLA) for NAGK and Golgi marker protein followed by ICC for tubulin or dynein light chain roadblock type 1 (DYNLRB1) in stage 3 neurons showed NAGK-Golgi complex colocalized with DYNLRB1 at the tips of microtubule (MT) fibers in axonal growth cones and in somatodendritic areas. PLAs for NAGK-dynein combined with tubulin or Golgi ICC showed similar signal patterns, indicating a three way interaction between NAGK, dynein, and Golgi in growing axons. In addition, overexpression of the NAGK gene and of kinase mutant NAGK genes increased axonal lengths, and knockdown of NAGK by small hairpin (sh) RNA reduced axonal lengths; suggesting a structural role for NAGK in axonal growth. Finally, transfection of 'DYNLRB1 (74-96)', a small peptide derived from DYNLRB1's C-terminal, which binds with NAGK, resulted in neurons with shorter axons in culture. The authors suggest a NAGK-dynein-Golgi tripartite interaction in growing axons is instrumental during early axonal development.
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Affiliation(s)
- Md. Ariful Islam
- Department of Anatomy, College of Medicine Dongguk University, Gyeongju 780-714,
Korea
| | - Syeda Ridita Sharif
- Department of Anatomy, College of Medicine Dongguk University, Gyeongju 780-714,
Korea
| | - HyunSook Lee
- Dongguk Medical Institute, College of Medicine Dongguk University, Gyeongju 780-714,
Korea
| | - Il Soo Moon
- Department of Anatomy, College of Medicine Dongguk University, Gyeongju 780-714,
Korea
- Dongguk Medical Institute, College of Medicine Dongguk University, Gyeongju 780-714,
Korea
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21
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Hochmal AK, Schulze S, Trompelt K, Hippler M. Calcium-dependent regulation of photosynthesis. Biochim Biophys Acta 2015; 1847:993-1003. [PMID: 25687895 DOI: 10.1016/j.bbabio.2015.02.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 02/05/2015] [Accepted: 02/07/2015] [Indexed: 01/03/2023]
Abstract
The understanding of calcium as a second messenger in plants has been growing intensively over the last decades. Recently, attention has been drawn to the organelles, especially the chloroplast but focused on the stromal Ca2+ transients in response to environmental stresses. Herein we will expand this view and discuss the role of Ca2+ in photosynthesis. Moreover we address of how Ca2+ is delivered to chloroplast stroma and thylakoids. Thereby, new light is shed on the regulation of photosynthetic electron flow and light-dependent metabolism by the interplay of Ca2+, thylakoid acidification and redox status. This article is part of a Special Issue entitled: Chloroplast biogenesis.
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Affiliation(s)
- Ana Karina Hochmal
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
| | - Stefan Schulze
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
| | - Kerstin Trompelt
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany.
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22
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Wada Y, Kusano H, Tsuge T, Aoyama T. Phosphatidylinositol phosphate 5-kinase genes respond to phosphate deficiency for root hair elongation in Arabidopsis thaliana. Plant J 2015; 81:426-37. [PMID: 25477067 DOI: 10.1111/tpj.12741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 11/22/2014] [Accepted: 11/25/2014] [Indexed: 05/07/2023]
Abstract
Plants drastically alter their root system architecture to adapt to different underground growth conditions. During phosphate (Pi) deficiency, most plants including Arabidopsis thaliana enhance the development of lateral roots and root hairs, resulting in bushy and hairy roots. To elucidate the signal pathway specific for the root hair elongation response to Pi deficiency, we investigated the expression of type-B phosphatidylinositol phosphate 5-kinase (PIP5K) genes, as a quantitative factor for root hair elongation in Arabidopsis. At young seedling stages, the PIP5K3 and PIP5K4 genes responded to Pi deficiency in steady-state transcript levels via PHR1-binding sequences (P1BSs) in their upstream regions. Both pip5k3 and pip5k4 single mutants, which exhibit short-root-hair phenotypes, remained responsive to Pi deficiency for root hair elongation; however the pip5k3pip5k4 double mutant exhibited shorter root hairs than the single mutants, and lost responsiveness to Pi deficiency at young seedling stages. In the tactical complementation line in which modified PIP5K3 and PIP5K4 genes with base substitutions in their P1BSs were co-introduced into the double mutant, root hairs of young seedlings had normal lengths under Pi-sufficient conditions, but were not responsive to Pi deficiency. From these results, we conclude that a Pi-deficiency signal is transferred to the pathway for root hair elongation via the PIP5K genes.
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Affiliation(s)
- Yukika Wada
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
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23
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Snider AJ, Ali WH, Sticca JA, Coant N, Ghaleb AM, Kawamori T, Yang VW, Hannun YA, Obeid LM. Distinct roles for hematopoietic and extra-hematopoietic sphingosine kinase-1 in inflammatory bowel disease. PLoS One 2014; 9:e113998. [PMID: 25460165 PMCID: PMC4252067 DOI: 10.1371/journal.pone.0113998] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 11/02/2014] [Indexed: 01/17/2023] Open
Abstract
Sphingosine kinase 1 (SK1), one of two SK enzymes, is highly regulated and has been shown to act as a focal point for the action of many growth factors and cytokines. SK1 leads to generation of sphingosine-1-phosphate (S1P) and potentially the activation of S1P receptors to mediate biologic effects. Our previous studies implicated SK1/S1P in the regulation of inflammatory processes, specifically in inflammatory bowel disease (IBD). These studies were conducted using a total body knockout mouse for SK1 and were unable to determine the source of SK1/S1P (hematopoietic or extra-hematopoietic) involved in the inflammatory responses. Therefore, bone marrow transplants were performed with wild-type (WT) and SK1-/- mice and colitis induced with dextran sulfate sodium (DSS). Irrespective of the source of SK1/S1P, bone marrow or tissue, DSS induced colitis in all mice; however, mice lacking SK1 in both hematopoietic and extra-hematopoietic compartments exhibited decreased crypt damage. Systemic inflammation was assessed, and mice with WT bone marrow demonstrated significant neutrophilia in response to DSS. In the local inflammatory response, mice lacking SK1/S1P in either bone marrow or tissue exhibited decreased induction of cytokines and less activation of STAT3 (signal transducer and activator of transcription 3). Interestingly, we determined that extra-hematopoietic SK1 is necessary for the induction of cyclooxygenase 2 (COX2) in colon epithelium in response to DSS-induced colitis. Taken together our data suggest that hematopoietic-derived SK1/S1P regulates specific aspects of the systemic inflammatory response, while extra-hematopoietic SK1 in the colon epithelium is necessary for the autocrine induction of COX2 in DSS-induced colitis.
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Affiliation(s)
- Ashley J. Snider
- Northport Veterans Affairs Medical Center, Northport, New York, United States of America
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
| | - Wahida H. Ali
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
| | - Jonathan A. Sticca
- University of South Carolina, School of Medicine, Columbia, South Carolina, United States of America
| | - Nicolas Coant
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
| | - Amr M. Ghaleb
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
| | - Toshihiko Kawamori
- University of Hawaii Cancer Center, Honolulu, Hawaii, United States of America
- Department of Pathology, Ichinomiya Nishi Hospital, Aichi, Japan
| | - Vincent W. Yang
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
| | - Yusuf A. Hannun
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
| | - Lina M. Obeid
- Northport Veterans Affairs Medical Center, Northport, New York, United States of America
- Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
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24
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Bi FC, Liu Z, Wu JX, Liang H, Xi XL, Fang C, Sun TJ, Yin J, Dai GY, Rong C, Greenberg JT, Su WW, Yao N. Loss of ceramide kinase in Arabidopsis impairs defenses and promotes ceramide accumulation and mitochondrial H2O2 bursts. Plant Cell 2014; 26:3449-67. [PMID: 25149397 PMCID: PMC4176443 DOI: 10.1105/tpc.114.127050] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/12/2014] [Accepted: 08/04/2014] [Indexed: 05/18/2023]
Abstract
Arabidopsis thaliana plants that lack ceramide kinase, encoded by ACCELERATED CELL DEATH5 (ACD5), display spontaneous programmed cell death late in development and accumulate substrates of ACD5. Here, we compared ceramide accumulation kinetics, defense responses, ultrastructural features, and sites of reactive oxygen species (ROS) production in wild-type and acd5 plants during development and/or Botrytis cinerea infection. Quantitative sphingolipid profiling indicated that ceramide accumulation in acd5 paralleled the appearance of spontaneous cell death, and it was accompanied by autophagy and mitochondrial ROS accumulation. Plants lacking ACD5 differed significantly from the wild type in their responses to B. cinerea, showing earlier and higher increases in ceramides, greater disease, smaller cell wall appositions (papillae), reduced callose deposition and apoplastic ROS, and increased mitochondrial ROS. Together, these data show that ceramide kinase greatly affects sphingolipid metabolism and the site of ROS accumulation during development and infection, which likely explains the developmental and infection-related cell death phenotypes. The acd5 plants also showed an early defect in restricting B. cinerea germination and growth, which occurred prior to the onset of cell death. This early defect in B. cinerea restriction in acd5 points to a role for ceramide phosphate and/or the balance of ceramides in mediating early antifungal responses that are independent of cell death.
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Affiliation(s)
- Fang-Cheng Bi
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Zhe Liu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jian-Xin Wu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Hua Liang
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
| | - Xue-Li Xi
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Ce Fang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Tie-Jun Sun
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jian Yin
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Guang-Yi Dai
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Chan Rong
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
| | - Wei-Wei Su
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Nan Yao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
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25
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Abstract
Adipose dysfunction resulting from chronic inflammation and impaired adipogenesis has increasingly been recognized as a major contributor to obesity-mediated insulin resistance, but the molecular mechanisms that maintain healthy adipocytes and limit adipose inflammation remain unclear. Here, we used genetic and pharmacological approaches to delineate a novel role for sphingosine kinase 1 (SK1) in metabolic disorders associated with obesity. SK1 phosphorylates sphingosine to form sphingosine 1 phosphate (S1P), a bioactive sphingolipid with numerous roles in inflammation. SK1 mRNA expression was increased in adipose tissue of diet-induced obese (DIO) mice and obese type 2 diabetic humans. In DIO mice, SK1 deficiency increased markers of adipogenesis and adipose gene expression of the anti-inflammatory molecules IL-10 and adiponectin and reduced adipose tissue macrophage (ATM) recruitment and proinflammatory molecules TNFα and IL-6. These changes were associated with enhanced insulin signaling in adipose and muscle and improved systemic insulin sensitivity and glucose tolerance in SK1(-/-) mice. Specific pharmacological inhibition of SK1 in WT DIO mice also reduced adipocyte and ATM inflammation and improved overall glucose homeostasis. These data suggest that the SK1-S1P axis could be an attractive target for the development of treatments to ameliorate adipose inflammation and insulin resistance associated with obesity and type 2 diabetes.
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Affiliation(s)
- Jing Wang
- Department of Cell Biology, Torrey Pines Institute for Molecular Studies, San Diego, California
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26
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Lee H, Cho SJ, Moon IS. The non-canonical effect of N-acetyl-D-glucosamine kinase on the formation of neuronal dendrites. Mol Cells 2014; 37:248-56. [PMID: 24625575 PMCID: PMC3969046 DOI: 10.14348/molcells.2014.2354] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/15/2014] [Accepted: 01/16/2014] [Indexed: 12/29/2022] Open
Abstract
N-acetylglucosamine kinase (GlcNAc kinase or NAGK; EC 2.7.1.59) is a N-acetylhexosamine kinase that belong to the sugar kinase/heat shock protein 70/actin superfamily. In this study, we investigated both the expression and function of NAGK in neurons. Immunohistochemistry of rat brain sections showed that NAGK was expressed at high levels in neurons but at low levels in astrocytes. Immunocytochemistry of rat hippocampal dissociate cultures confirmed these findings and showed that NAGK was also expressed at low levels in oligodendrocytes. Furthermore, several NAGK clusters were observed in the nucleoplasm of both neuron and glia. The overexpression of EGFP- or RFP (DsRed2)-tagged NAGK in rat hippocampal neurons (DIV 5-9) increased the complexity of dendritic architecture by increasing the numbers of primary dendrites and dendritic branches. In contrast, knockdown of NAGK by shRNA resulted in dendrite degeneration, and this was prevented by the co-expression of RFP-tagged NAGK. These results suggest that the upregulation of dendritic complexity is a non-canonical function of NAGK.
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Affiliation(s)
- HyunSook Lee
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 780-714,
Korea
| | - Sun-Jung Cho
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 780-714,
Korea
| | - Il Soo Moon
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 780-714,
Korea
- Dongguk Medical Institute, Dongguk University College of Medicine, Gyeongju 780-714,
Korea
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27
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Abstract
The sphingosine kinases (SphKs) have relatively recently been implicated in contributing to malignant cellular processes with particular interest in the oncogenic properties of SPHK1. Whilst SPHK1 has received considerable attention as a putative oncoprotein, SPHK2 has been much more difficult to study, with often conflicting data surrounding its role in cancer. Initial studies focused on non-haemopoietic malignancies, however a growing body of literature on the role of sphingolipid metabolism in haemopoietic malignancies is now emerging. This review provides an overview of the current state of knowledge of the SphKs and the bioactive lipid sphingosine 1-phosphate (S1P), the product of the reaction they catalyse. It then reviews the current literature regarding the roles of S1P and the SphKs in haemopoietic malignancies and discusses the compounds currently available that modulate sphingolipid metabolism and their potential and shortcomings as therapeutic agents for the treatment of haematological malignancies.
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Affiliation(s)
- Craig T Wallington-Beddoe
- Westmead Institute for Cancer Research, Westmead Millennium Institute, The University of Sydney, Sydney, NSW, Australia
| | | | - Linda J Bendall
- Westmead Institute for Cancer Research, Westmead Millennium Institute, The University of Sydney, Sydney, NSW, Australia
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28
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Garanto A, Mandal NA, Egido-Gabás M, Marfany G, Fabriàs G, Anderson RE, Casas J, Gonzàlez-Duarte R. Specific sphingolipid content decrease in Cerkl knockdown mouse retinas. Exp Eye Res 2013; 110:96-106. [PMID: 23501591 DOI: 10.1016/j.exer.2013.03.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/19/2013] [Accepted: 03/04/2013] [Indexed: 01/12/2023]
Abstract
Sphingolipids (SPLs) are finely tuned structural compounds and bioactive molecules involved in membrane fluidity and cellular homeostasis. The core sphingolipid, ceramide (CER), and its derivatives, regulate several crucial processes in neuronal cells, among them cell differentiation, cell-cell interactions, membrane conductance, synaptic transmission, and apoptosis. Mutations in Ceramide Kinase-Like (CERKL) cause autosomal recessive Retinitis Pigmentosa and Cone Rod Dystrophy. The presence of a conserved lipid kinase domain and the overall similarity with CERK suggested that CERKL might play a role in the SPL metabolism as a CER kinase. Unfortunately, CERKL function and substrate(s), as well as its contribution to the retinal etiopathology, remain as yet unknown. In this work we aimed to characterize the mouse retinal sphingolipidome by UPLC-TOF to first, thoroughly investigate the SPL composition of the murine retina, compare it to our Cerkl -/- model, and finally assess new possible CERKL substrates by phosphorus quantification and protein-lipid overlay. Our results showed a consistent and notable decrease of the retinal SPL content (mainly ranging from 30% to 60%) in the Cerkl -/- compared to WT retinas, which was particularly evident in the glucosyl/galactosyl ceramide species (Glc/GalCer) whereas the phospholipids and neutral lipids remained unaltered. Moreover, evidence in favor of CERKL binding to GlcCer, GalCer and sphingomyelin has been gathered. Altogether, these results highlight the involvement of CERKL in the SPL metabolism, question its role as a kinase, and open new scenarios concerning its function.
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Affiliation(s)
- Alejandro Garanto
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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Zhu T, Chappel JC, Hsu FF, Turk J, Aurora R, Hyrc K, De Camilli P, Broekelmann TJ, Mecham RP, Teitelbaum SL, Zou W. Type I phosphotidylinosotol 4-phosphate 5-kinase γ regulates osteoclasts in a bifunctional manner. J Biol Chem 2013; 288:5268-77. [PMID: 23300084 PMCID: PMC3581369 DOI: 10.1074/jbc.m112.446054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Indexed: 12/22/2022] Open
Abstract
Type 1 phosphotidylinosotol-4 phosphate 5 kinase γ (PIP5KIγ) is central to generation of phosphotidylinosotol (4,5)P(2) (PI(4,5)P(2)). PIP5KIγ also participates in cytoskeletal organization by delivering talin to integrins, thereby enhancing their ligand binding capacity. As the cytoskeleton is pivotal to osteoclast function, we hypothesized that absence of PIP5KIγ would compromise their resorptive capacity. Absence of the kinase diminishes PI(4,5) abundance and desensitizes precursors to RANK ligand-stimulated differentiation. Thus, PIP5KIγ(-/-) osteoclasts are reduced in number in vitro and confirm physiological relevance in vivo. Despite reduced numbers, PIP5KIγ(-/-) osteoclasts surprisingly have normal cytoskeletons and effectively resorb bone. PIP5KIγ overexpression, which increases PI(4,5)P(2), also delays osteoclast differentiation and reduces cell number but in contrast to cells lacking the kinase, its excess disrupts the cytoskeleton. The cytoskeleton-disruptive effects of excess PIP5KIγ reflect its kinase activity and are independent of talin recognition. The combined arrested differentiation and disorganized cytoskeleton of PIP5KIγ-transduced osteoclasts compromises bone resorption. Thus, optimal PIP5KIγ and PI(4,5)P(2) expression, by osteoclasts, are essential for skeletal homeostasis.
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Affiliation(s)
| | | | | | | | - Rajeev Aurora
- the Department of Molecular Microbiology and Immunology, St. Louis University School of Medicine, St. Louis, Missouri 63104, and
| | - Krzysztof Hyrc
- Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis School of Medicine, St. Louis, Missouri 63110
| | - Pietro De Camilli
- the Department of Cell Biology and Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520
| | | | | | | | - Wei Zou
- From the Department of Pathology and Immunology
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Neely GG, Rao S, Costigan M, Mair N, Racz I, Milinkeviciute G, Meixner A, Nayanala S, Griffin RS, Belfer I, Dai F, Smith S, Diatchenko L, Marengo S, Haubner BJ, Novatchkova M, Gibson D, Maixner W, Pospisilik JA, Hirsch E, Whishaw IQ, Zimmer A, Gupta V, Sasaki J, Kanaho Y, Sasaki T, Kress M, Woolf CJ, Penninger JM. Construction of a global pain systems network highlights phospholipid signaling as a regulator of heat nociception. PLoS Genet 2012; 8:e1003071. [PMID: 23236288 PMCID: PMC3516557 DOI: 10.1371/journal.pgen.1003071] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 09/21/2012] [Indexed: 01/06/2023] Open
Abstract
The ability to perceive noxious stimuli is critical for an animal's survival in the face of environmental danger, and thus pain perception is likely to be under stringent evolutionary pressure. Using a neuronal-specific RNAi knock-down strategy in adult Drosophila, we recently completed a genome-wide functional annotation of heat nociception that allowed us to identify α2δ3 as a novel pain gene. Here we report construction of an evolutionary-conserved, system-level, global molecular pain network map. Our systems map is markedly enriched for multiple genes associated with human pain and predicts a plethora of novel candidate pain pathways. One central node of this pain network is phospholipid signaling, which has been implicated before in pain processing. To further investigate the role of phospholipid signaling in mammalian heat pain perception, we analysed the phenotype of PIP5Kα and PI3Kγ mutant mice. Intriguingly, both of these mice exhibit pronounced hypersensitivity to noxious heat and capsaicin-induced pain, which directly mapped through PI3Kγ kinase-dead knock-in mice to PI3Kγ lipid kinase activity. Using single primary sensory neuron recording, PI3Kγ function was mechanistically linked to a negative regulation of TRPV1 channel transduction. Our data provide a systems map for heat nociception and reinforces the extraordinary conservation of molecular mechanisms of nociception across different species. Nociception is the perception of noxious, potentially damaging stimuli; and this pain or its equivalent behavioral readout is evolutionarily conserved from fruit flies to humans. Using genetic techniques in the fruit fly, we have been able to evaluate the potential functional contribution of every gene in the fruit fly genome for a role in avoidance of high noxious temperatures (heat pain-like responses). Using this functional genomics data set, we have developed a conserved network map of heat pain/nociception that predicts numerous conserved genes and pathways as novel pain pathways, including phospholipid signaling. Studies in multiple mutant mice confirmed a role for lipid signaling in pain perception, and more specifically we identify the critical lipid kinase (PI3Kγ) as a negative regulator of TRPV1 (receptor for noxious heat and capsaicin, the active component in chili peppers) signaling. This finding shows that our fly-based genetic pain network map is a valuable tool for the discovery of novel “nociception genes” in mammals.
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Affiliation(s)
- G Gregory Neely
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.
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31
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Menon KMJ, Menon B. Structure, function and regulation of gonadotropin receptors - a perspective. Mol Cell Endocrinol 2012; 356:88-97. [PMID: 22342845 PMCID: PMC3327826 DOI: 10.1016/j.mce.2012.01.021] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 01/13/2012] [Accepted: 01/24/2012] [Indexed: 11/19/2022]
Abstract
Luteinizing hormone receptor and follicle stimulating hormone receptor play a crucial role in female and male reproduction. Significant new information has emerged about the structure, mechanism of activation, and regulation of expression of these receptors. Here we provide an overview of the current information on those aspects with an in-depth discussion of the recent developments in the post-transcriptional mechanism of LH receptor expression mediated by a specific LH receptor mRNA binding protein, designated as LRBP. LRBP was identified by electrophoretic gel mobility shift assay using cytosolic fractions from ovaries in the down regulated state. LRBP was purified, its binding site on LH receptor mRNA was identified and characterized. During ligand-induced down regulation, LRBP expression is increased through the cAMP/PKA and ERK signaling pathway, is translocated to translating ribosomes, binds LH receptor mRNA and forms an untranslatable ribonucleoprotein complex. This complex is then routed to the mRNA degradation machinery resulting in diminished levels of both LHR mRNA and cell surface expression of LH receptor. The studies leading to these conclusions are presented.
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Affiliation(s)
- K M J Menon
- Departments of Obstetrics/Gynecology and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-0617, United States.
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Bachmaier K, Guzman E, Kawamura T, Gao X, Malik AB. Sphingosine kinase 1 mediation of expression of the anaphylatoxin receptor C5L2 dampens the inflammatory response to endotoxin. PLoS One 2012; 7:e30742. [PMID: 22355325 PMCID: PMC3280265 DOI: 10.1371/journal.pone.0030742] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/27/2011] [Indexed: 11/30/2022] Open
Abstract
The complement anaphylatoxin C5a has a pathogenetic role in endotoxin-induced lung inflammatory injury by regulating phagocytic cell migration and activation. Endotoxin and C5a activate the enzyme sphingosine kinase (Sphk) 1 to generate the signaling lipid sphingosine-1-phosphate (S1P), a critical regulator of phagocyte function. We assessed the function of Sphk1 and S1P in experimental lung inflammatory injury and determined their roles in anaphylatoxin receptor signaling and on the expression of the two C5a receptors, C5aR (CD88) and C5L2, on phagocytes. We report that Sphk1 gene deficient (Sphk1−/−) mice had augmented lung inflammatory response to endotoxin compared to wild type mice. Sphk1 was required for C5a-mediated reduction in cytokine and chemokine production by macrophages. Moreover, neutrophils from Sphk1−/− mice failed to upregulate the anaphylatoxin receptor C5L2 in response to LPS. Exogenous S1P restored C5L2 cell surface expression of Sphk1−/− mouse neutrophils to wild type levels but had no effect on cell surface expression of the other anaphylatoxin receptor, CD88. These results provide the first genetic evidence of the crucial role of Sphk1 in regulating the balance between expression of CD88 and C5L2 in phagocytes. S1P-mediated up-regulation of C5L2 is a novel therapeutic target for mitigating endotoxin-induced lung inflammatory injury.
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Affiliation(s)
- Kurt Bachmaier
- Department of Pharmacology, College of Medicine, Center of Lung and Vascular Biology, University of Illinois, Chicago, Illinois, United States of America.
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Okada T, Nakamura SI. [Role of S1P acting both inside and outside the cells]. Seikagaku 2012; 84:92-101. [PMID: 22550899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Taro Okada
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kusunoki-Cho 7-5-1, Kobe 650-0017, Japan
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Yang J, Ji M, Zhou Z, Sun J, Peng Y. Sphingosine kinase-signaling pathway: a possible therapeutic target for post-operative cognitive dysfunction. Acta Anaesthesiol Scand 2012; 56:260-1. [PMID: 22091624 DOI: 10.1111/j.1399-6576.2011.02539.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Quorum sensing (QS) enables bacterial multicellularity and selective advantage for communicating populations. While genetic “switching” phenomena are a common feature, their mechanistic underpinnings have remained elusive. The interplay between circuit components and their regulation are intertwined and embedded. Observable phenotypes are complex and context dependent. We employed a combination of experimental work and mathematical models to decipher network connectivity and signal transduction in the autoinducer-2 (AI-2) quorum sensing system of E. coli. Negative and positive feedback mechanisms were examined by separating the network architecture into sub-networks. A new unreported negative feedback interaction was hypothesized and tested via a simple mathematical model. Also, the importance of the LsrR regulator and its determinant role in the E. coli QS “switch”, normally masked by interfering regulatory loops, were revealed. Our simple model allowed mechanistic understanding of the interplay among regulatory sub-structures and their contributions to the overall native functioning network. This “bottom up” approach in understanding gene regulation will serve to unravel complex QS network architectures and lead to the directed coordination of emergent behaviors. Quorum sensing is a mechanism by which bacterial cells communicate within a population. One particular form of communication in E. coli is through a universal signaling molecule known as autoinducer 2. Although the importance of this form of cell-cell interaction has been recognized in the formation of biofilms and virulent infections, the mechanisms by which this form of communication is regulated is still not well understood. In this paper, we presented a method of unraveling these mechanisms by using a combination of experimental work and mathematical models. We took apart the network architecture and isolated the different components. The examination of these isolated sub-networks provided us with a better understanding of the underlying mechanisms that control and regulate bacterial quorum sensing. We were also able to predict new network interactions with the help of our mathematical models. This bottom up approach, combined with our modeling efforts, proved effective in unraveling the mechanisms of quorum sensing in E. coli.
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Affiliation(s)
- Sara Hooshangi
- College of Professional Studies, The George Washington University, Washington, DC, United States of America
- Fischell Department of Bioengineering, University of Maryland College Park, College Park, Maryland, United States of America
| | - William E. Bentley
- Fischell Department of Bioengineering, University of Maryland College Park, College Park, Maryland, United States of America
- Institute of Bioscience and Biotechnology Research, University of Maryland, College Park, Maryland, United States of America
- * E-mail:
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36
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Liu SQ, Qin MB, Huang JA, Zhong YY, Tang GD, Jiang HX. [Effect of sphingosine kinase 1 on the apoptosis, migration and invasion of colon cancer HT-29 cells and its molecular mechanisms]. Zhonghua Zhong Liu Za Zhi 2011; 33:178-182. [PMID: 21575515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVE To investigate the effect of sphingosine kinase 1 (SphK1) on the proliferation, apoptosis, migration and invasion of colon cancer TH-29 cells and to explore its molecular mechanisms. METHODS Phorbol 12-myristate 13-acetate (PMA) was used to induce the activity of SphK1 and N, N-dimethylsphingosine (DMS) was used to suppress the activity of SphK1. Cell prolieration and apoptosis were detected by MTT assay and flow cytometry, respectively. The migration and invasion capabilities of the cells were assessed in Transwell chambers. The activity of SphK1 was assayed by autoradiography. Western blot was used to evaluate the protein expression of SphK1, p38, phosphorylated p38 (p-p38) and SAPK/JNK. RESULTS PMA and DMS were able to induce and suppress the activity and protein expression of SphK1 in a time-dependent manner, respectively. PMA enhanced and DMS suppressed the cell viability in a time- and dose-dependent manner. Being treated with 100 nmol/L PMA or 50 µmol/L DMS for 0, 6, 12, 24 h, the cell apoptosis rates of PMA group were (9.35 ± 0.84)%, (7.61 ± 0.48)%, (5.53 ± 0.76)% and (0.56 ± 0.33)%, contrastly, that of DMS group were (9.18 ± 0.94)%, (12.06 ± 1.41)%, (19.80 ± 2.36)% and (31.85 ± 3.60)%, respectively. Compared with the control group, the cell migration and invasion capabilities of the PMA group were significantly enhanced, and that of the DMS group were significantly suppressed. The migration cell number of control, PMA and DMS groups were 68.75 ± 6.15, 109.33 ± 11.63 and 10.83 ± 2.48, the invasion cell number of control, PMA and DMS groups were 55.42 ± 4.50, 90.58 ± 7.06 and 9.58 ± 2.39, respectively. With the elevating activity and expression of SphK1, the protein expressions of p38, p-p38 and SAPK/JNK were strikingly suppressed. On the contrary, after treating with DMS the protein expressions of p38, p-p38 and SAPK/JNK were enhanced. CONCLUSIONS SphK1 potently enhances the prolieration, migration and invasion of colon cancer HT-29 cells, meanwhile suppresses the cell apoptosis. The suppressing of the p38 and SAPK/JNK signalling pathways may be one of its molecular mechanisms.
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Affiliation(s)
- Shi-quan Liu
- Department of Gastroenterology, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
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Shirai K, Kaneshiro T, Wada M, Furuya H, Bielawski J, Hannun YA, Obeid LM, Ogretmen B, Kawamori T. A role of sphingosine kinase 1 in head and neck carcinogenesis. Cancer Prev Res (Phila) 2011; 4:454-62. [PMID: 21209394 DOI: 10.1158/1940-6207.capr-10-0299] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is important to identify novel and effective targets for cancer prevention and therapy against head and neck squamous cell carcinoma (HNSCC), one of the most lethal cancers. Accumulating evidence suggests that the bioactive sphingolipids, such as sphingosine-1-phosphate (S1P) and its generating enzyme, sphingosine kinase 1 (SphK1) play pivotal roles in several important biological functions including promoting tumor growth and carcinogenesis. However, roles of SphK1/S1P in HNSCC development and/or progression have not been defined previously. Therefore, in this study, we first analyzed the expression of SphK1 in human HNSCC tumor samples and normal head & neck tissues (n = 78 and 17, respectively) using immunohistochemistry. The data showed that SphK1 is overexpressed in all of the HNSCC tumors tested (stages I-IV). We next investigated whether SphK1 is necessary for HNSCC development. To define the role of SphK1/S1P in HNSCC development, we utilized 4-nitroquinoline-1-oxide (4-NQO)-induced HNSCC model in wild-type mice compared with SphK1(-/-) knockout (KO) mice. Remarkably, we found that the genetic loss of SphK1, which reduced S1P generation, significantly prevented 4-NQO-induced HNSCC carcinogenesis, with decreased tumor incidence, multiplicity, and volume when compared with controls. Moreover, our data indicated that prevention of 4-NQO-induced HNSCC development in SphK1(-/-) KO mice might be associated with decreased cell proliferation, increased levels of cleaved (active) caspase 3, and downregulation of phospho (active) AKT expression. Thus, these novel data suggest that SphK1/S1P signaling may play important roles in HNSCC carcinogenesis, and that targeting SphK1/S1P might provide a novel strategy for chemoprevention and treatment against HNSCC.
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Affiliation(s)
- Keisuke Shirai
- Department of Hematology/Oncology, Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
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Xia P, Wadham C. Sphingosine 1-phosphate, a key mediator of the cytokine network: juxtacrine signaling. Cytokine Growth Factor Rev 2010; 22:45-53. [PMID: 21051273 DOI: 10.1016/j.cytogfr.2010.09.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 09/21/2010] [Indexed: 01/21/2023]
Abstract
Sphingosine 1-phosphate (S1P) is a sphingolipid metabolite, which has emerged as an important signaling mediator participating in the regulation of multiple cellular processes. The discovery of a family of S1P receptors, together with the more recently identified intracellular targets, has provided fundamental understanding of the multi-faceted actions of S1P. Evidence from both in vitro and in vivo studies has implicated the S1P signaling system in the control of immunity, inflammation and many associated diseases. Enigmatically, S1P appears to have both pro- and anti-inflammatory effects depending on the cell context. Here, we review this emerging area and argue for a pivotal role for S1P, as a key mediator of the cytokine network, acting through juxtacrine signaling in the immune system.
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Affiliation(s)
- Pu Xia
- Signal Transduction Program, Centenary Institute and Sydney Medical School University of Sydney, Australia.
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Akimana C, Al-Khodor S, Abu Kwaik Y. Host factors required for modulation of phagosome biogenesis and proliferation of Francisella tularensis within the cytosol. PLoS One 2010; 5:e11025. [PMID: 20552012 PMCID: PMC2883998 DOI: 10.1371/journal.pone.0011025] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/13/2010] [Indexed: 01/07/2023] Open
Abstract
Francisella tularensis is a highly infectious facultative intracellular bacterium that can be transmitted between mammals by arthropod vectors. Similar to many other intracellular bacteria that replicate within the cytosol, such as Listeria, Shigella, Burkholderia, and Rickettsia, the virulence of F. tularensis depends on its ability to modulate biogenesis of its phagosome and to escape into the host cell cytosol where it proliferates. Recent studies have identified the F. tularensis genes required for modulation of phagosome biogenesis and escape into the host cell cytosol within human and arthropod-derived cells. However, the arthropod and mammalian host factors required for intracellular proliferation of F. tularensis are not known. We have utilized a forward genetic approach employing genome-wide RNAi screen in Drosophila melanogaster-derived cells. Screening a library of approximately 21,300 RNAi, we have identified at least 186 host factors required for intracellular bacterial proliferation. We silenced twelve mammalian homologues by RNAi in HEK293T cells and identified three conserved factors, the PI4 kinase PI4KCA, the ubiquitin hydrolase USP22, and the ubiquitin ligase CDC27, which are also required for replication in human cells. The PI4KCA and USP22 mammalian factors are not required for modulation of phagosome biogenesis or phagosomal escape but are required for proliferation within the cytosol. In contrast, the CDC27 ubiquitin ligase is required for evading lysosomal fusion and for phagosomal escape into the cytosol. Although F. tularensis interacts with the autophagy pathway during late stages of proliferation in mouse macrophages, this does not occur in human cells. Our data suggest that F. tularensis utilizes host ubiquitin turnover in distinct mechanisms during the phagosomal and cytosolic phases and phosphoinositide metabolism is essential for cytosolic proliferation of F. tularensis. Our data will facilitate deciphering molecular ecology, patho-adaptation of F. tularensis to the arthropod vector and its role in bacterial ecology and patho-evolution to infect mammals.
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Affiliation(s)
- Christine Akimana
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Souhaila Al-Khodor
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- Department of Biology, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
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Dayon A, Brizuela L, Martin C, Mazerolles C, Pirot N, Doumerc N, Nogueira L, Golzio M, Teissié J, Serre G, Rischmann P, Malavaud B, Cuvillier O. Sphingosine kinase-1 is central to androgen-regulated prostate cancer growth and survival. PLoS One 2009; 4:e8048. [PMID: 19956567 PMCID: PMC2779655 DOI: 10.1371/journal.pone.0008048] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 11/02/2009] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Sphingosine kinase-1 (SphK1) is an oncogenic lipid kinase notably involved in response to anticancer therapies in prostate cancer. Androgens regulate prostate cancer cell proliferation, and androgen deprivation therapy is the standard of care in the management of patients with advanced disease. Here, we explored the role of SphK1 in the regulation of androgen-dependent prostate cancer cell growth and survival. METHODOLOGY/PRINCIPAL FINDINGS Short-term androgen removal induced a rapid and transient SphK1 inhibition associated with a reduced cell growth in vitro and in vivo, an event that was not observed in the hormono-insensitive PC-3 cells. Supporting the critical role of SphK1 inhibition in the rapid effect of androgen depletion, its overexpression could impair the cell growth decrease. Similarly, the addition of dihydrotestosterone (DHT) to androgen-deprived LNCaP cells re-established cell proliferation, through an androgen receptor/PI3K/Akt dependent stimulation of SphK1, and inhibition of SphK1 could markedly impede the effects of DHT. Conversely, long-term removal of androgen support in LNCaP and C4-2B cells resulted in a progressive increase in SphK1 expression and activity throughout the progression to androgen-independence state, which was characterized by the acquisition of a neuroendocrine (NE)-like cell phenotype. Importantly, inhibition of the PI3K/Akt pathway--by negatively impacting SphK1 activity--could prevent NE differentiation in both cell models, an event that could be mimicked by SphK1 inhibitors. Fascinatingly, the reversability of the NE phenotype by exposure to normal medium was linked with a pronounced inhibition of SphK1 activity. CONCLUSIONS/SIGNIFICANCE We report the first evidence that androgen deprivation induces a differential effect on SphK1 activity in hormone-sensitive prostate cancer cell models. These results also suggest that SphK1 activation upon chronic androgen deprivation may serve as a compensatory mechanism allowing prostate cancer cells to survive in androgen-depleted environment, giving support to its inhibition as a potential therapeutic strategy to delay/prevent the transition to androgen-independent prostate cancer.
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Affiliation(s)
- Audrey Dayon
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
| | - Leyre Brizuela
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
| | - Claire Martin
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
| | - Catherine Mazerolles
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- CHU Toulouse, Hôpital Rangueil, Laboratoire Anatomie Pathologique et Histologie-Cytologie, Toulouse, France
| | - Nelly Pirot
- Université de Toulouse, UPS, IPBS, Toulouse, France
| | - Nicolas Doumerc
- Université de Toulouse, UPS, IPBS, Toulouse, France
- CHU Toulouse, Hôpital Rangueil, Service d'Urologie et de Transplantation Rénale, Toulouse, France
| | - Leonor Nogueira
- CHU Toulouse, Hôpital Purpan, Laboratoire de Biologie Cellulaire et Cytologie, Toulouse, France
| | - Muriel Golzio
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
| | - Justin Teissié
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
| | - Guy Serre
- CHU Toulouse, Hôpital Purpan, Laboratoire de Biologie Cellulaire et Cytologie, Toulouse, France
| | - Pascal Rischmann
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
- CHU Toulouse, Hôpital Rangueil, Service d'Urologie et de Transplantation Rénale, Toulouse, France
| | - Bernard Malavaud
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
- CHU Toulouse, Hôpital Rangueil, Service d'Urologie et de Transplantation Rénale, Toulouse, France
| | - Olivier Cuvillier
- CNRS, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, UPS, IPBS, Toulouse, France
- CHU Toulouse, Hôpital Rangueil, Service d'Urologie et de Transplantation Rénale, Toulouse, France
- * E-mail:
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Hengst JA, Guilford JM, Fox TE, Wang X, Conroy EJ, Yun JK. Sphingosine kinase 1 localized to the plasma membrane lipid raft microdomain overcomes serum deprivation induced growth inhibition. Arch Biochem Biophys 2009; 492:62-73. [PMID: 19782042 DOI: 10.1016/j.abb.2009.09.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 09/18/2009] [Accepted: 09/19/2009] [Indexed: 11/18/2022]
Abstract
Several studies have demonstrated that sphingosine kinase 1 (SphK1) translocates to the plasma membrane (PM) upon its activation and further suggested the plasma membrane lipid raft microdomain (PMLRM) as a target for SphK1 relocalization. To date, however, direct evidence of SphK1 localization to the PMLRM has been lacking. In this report, using multiple biochemical and subcellular fractionation techniques we demonstrate that endogenous SphK1 protein and its substrate, D-erythro-sphingosine, are present within the PMLRM. Additionally, we demonstrate that the PMA stimulation of SphK1 localized to the PMLRM results in production of sphingosine-1-phosphate as well as induction of cell growth under serum deprivation conditions. We further report that Ser225Ala and Thr54Cys mutations, reported to abrogate phosphatidylserine binding, block SphK1 targeting to the PMLRM and SphK1 induced cell growth. Together these findings provide direct evidence that the PMLRM is the major site of action for SphK1 to overcome serum-deprived cell growth inhibition.
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Affiliation(s)
- Jeremy A Hengst
- Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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42
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van Damme M, Zeilmaker T, Elberse J, Andel A, de Sain-van der Velden M, van den Ackerveken G. Downy mildew resistance in Arabidopsis by mutation of HOMOSERINE KINASE. Plant Cell 2009; 21:2179-89. [PMID: 19622802 PMCID: PMC2729605 DOI: 10.1105/tpc.109.066811] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plant disease resistance is commonly triggered by early pathogen recognition and activation of immunity. An alternative form of resistance is mediated by recessive downy mildew resistant 1 (dmr1) alleles in Arabidopsis thaliana. Map-based cloning revealed that DMR1 encodes homoserine kinase (HSK). Six independent dmr1 mutants each carry a different amino acid substitution in the HSK protein. Amino acid analysis revealed that dmr1 mutants contain high levels of homoserine that is undetectable in wild-type plants. Surprisingly, the level of amino acids downstream in the aspartate (Asp) pathway was not reduced in dmr1 mutants. Exogenous homoserine does not directly affect pathogen growth but induces resistance when infiltrated in Arabidopsis. We provide evidence that homoserine accumulation in the chloroplast triggers a novel form of downy mildew resistance that is independent of known immune responses.
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Affiliation(s)
- Mireille van Damme
- Plant-Microbe Interactions, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
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43
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Baker AK, Wang R, Mackman N, Luyendyk JP. Rapamycin enhances LPS induction of tissue factor and tumor necrosis factor-alpha expression in macrophages by reducing IL-10 expression. Mol Immunol 2009; 46:2249-55. [PMID: 19447494 DOI: 10.1016/j.molimm.2009.04.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 03/31/2009] [Accepted: 04/07/2009] [Indexed: 01/04/2023]
Abstract
Bacterial lipopolysaccharide (LPS) induces monocytes/macrophages to express proinflammatory cytokines and tissue factor (TF), the primary activator of the coagulation cascade. Anti-inflammatory signaling pathways including the phosphatidylinositol-3-kinase (PI3K)-Akt pathway inhibit proinflammatory and TF gene expression in macrophages. We determined the role of Akt, the mammalian target of rapamycin (mTOR) and interleukin-10 in the inhibition of LPS-induced proinflammatory cytokine and TF gene expression in peritoneal macrophages (PMs). We used wild type (WT) peritoneal macrophages (PMs), and PMs from PTEN(flox/flox)/LysMCre mice (PTEN(-/-) PMs), which have increased Akt activity. Pharmacologic inhibition of mTOR with rapamycin inhibited LPS induction of IL-10 mRNA and protein, and enhanced the expression of TF and the proinflammatory cytokine TNFalpha in WT PMs. Furthermore, neutralizing IL-10 with anti-IL-10 antibody enhanced LPS induction of TNFalpha and TF expression in WT PMs. The addition of recombinant IL-10 abolished rapamycin enhancement of LPS-induced TNFalpha and TF expression in WT PMs. Consistent with enhanced Akt activation, LPS-induced IL-10 expression was increased in PTEN(-/-) PMs compared to WT PMs. In contrast, LPS-induced TNFalpha and TF expression was significantly reduced in PTEN(-/-) PMs compared to WT PMs. However, the neutralizing IL-10 antibody did not completely prevent inhibition of LPS-induced TNFalpha and TF expression in PTEN(-/-) PMs. The results indicate that mTOR dependent IL-10 expression leads to inhibition of LPS induction of TF and the proinflammatory cytokine TNFalpha in WT macrophages. In contrast, the decrease in LPS-induced TNFalpha and TF expression in PTEN(-/-) PMs also requires an IL-10-independent pathway.
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Affiliation(s)
- Alyson K Baker
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, 3901 Rainbow Boulevard, MS-1018, Kansas City, KS 66160, USA
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44
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Bergelin N, Blom T, Heikkilä J, Löf C, Alam C, Balthasar S, Slotte JP, Hinkkanen A, Törnquist K. Sphingosine kinase as an oncogene: autocrine sphingosine 1-phosphate modulates ML-1 thyroid carcinoma cell migration by a mechanism dependent on protein kinase C-alpha and ERK1/2. Endocrinology 2009; 150:2055-63. [PMID: 19116345 DOI: 10.1210/en.2008-0625] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sphingosine 1-phosphate (S1P) induces migration of the human thyroid follicular carcinoma cell line ML-1 by activation of S1P(1) and S1P(3) receptors, G(i) proteins, and the phosphatidylinositol 3-kinase-Akt pathway. Because sphingosine kinase isoform 1 (SK) recently has been implicated as an oncogene in various cancer cell systems, we investigated the functions of SK in the migration, proliferation and adhesion of the ML-1 cell line. SK overexpressing ML-1 cells show an enhanced secretion of S1P, which can be attenuated, by inhibiting SK activity and a multidrug-resistant transport protein (ATP-binding cassette transporter). Furthermore, overexpression of SK enhances serum-induced migration of ML-1 cells, which can be attenuated by blocking ATP-binding cassette transporter and SK, suggesting that the migration is mediated by autocrine signaling through secretion of S1P. Inhibition of protein kinase C alpha, with both small interfering RNA (siRNA) and small molecular inhibitors attenuates migration in SK overexpressing cells. In addition, SK-overexpressing cells show an impaired adhesion, slower cell growth, and an up-regulation of ERK1/2 phosphorylation, as compared with cells expressing a dominant-negative SK. Taken together, we present evidence suggesting that SK enhances migration of ML-1 cells by an autocrine mechanism and that the S1P-evoked migration is dependent on protein kinase C alpha, ERK1/2, and SK.
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Affiliation(s)
- N Bergelin
- Department of Biology, Abo Akademi University, BioCity, Tykistökatu 6, 20520 Turku, Finland
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45
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Zhang J, Luo R, Wu H, Wei S, Han W, Li G. Role of type Ialpha phosphatidylinositol-4-phosphate 5-kinase in insulin secretion, glucose metabolism, and membrane potential in INS-1 beta-cells. Endocrinology 2009; 150:2127-35. [PMID: 19116346 DOI: 10.1210/en.2008-0516] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Insulin secretion from beta-cells is regulated by a complex signaling network. Our earlier study has reported that Rac1 participates in glucose- and cAMP-induced insulin secretion probably via maintaining a functional actin structure for recruitment of insulin granules. Type Ialpha phosphatidylinositol-4-phosphate 5-kinase (PIP5K-Ialpha) is a downstream effector of Rac1 and a critical enzyme for synthesis of phosphatidylinositol-4,5-bisphosphate (PIP(2)). By using an RNA interference technique, PIP5K-Ialpha in INS-1 beta-cells could be specifically knocked down by 70-75%. PIP5K-Ialpha knockdown disrupted filamentous actin structure and caused changes in cell morphology. In addition, PIP(2) content in the plasma membrane was reduced and the glucose effect on PIP(2) was abolished but without affecting glucose-induced formation of inositol 1,4,5-trisphosphate. At basal conditions (2.8 mM glucose), PIP5K-Ialpha knockdown doubled insulin secretion, elevated glucose metabolic rate, depolarized resting membrane potential, and raised cytoplasmic free Ca(2+) levels ([Ca(2+)](i)). The total insulin release at high glucose was increased upon PIP5K-Ialpha knockdown. However, the percent increment of insulin secretion by high glucose and forskolin over the basal release was significantly reduced, an effect more apparent on the late phase of insulin secretion. Metabolism and [Ca(2+)](i) rises at high glucose were also attenuated in cells after PIP5K-Ialpha knockdown. In contrast, PIP5K-Ialpha knockdown had no effect on cell growth and viability. Taken together, our data suggest that PIP5K-Ialpha may play an important role in both the proximal and distal steps of signaling cascade for insulin secretion in beta-cells.
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Affiliation(s)
- Jiping Zhang
- Cardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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46
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47
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Wei C, Amos CI, Zhang N, Zhu J, Wang X, Frazier ML. Chemopreventive efficacy of rapamycin on Peutz-Jeghers syndrome in a mouse model. Cancer Lett 2009; 277:149-54. [PMID: 19147279 DOI: 10.1016/j.canlet.2008.11.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 11/21/2008] [Accepted: 11/28/2008] [Indexed: 02/06/2023]
Abstract
Germline mutations in LKB1 cause Peutz-Jeghers syndrome (PJS), an autosomal dominant disorder with a predisposition to gastrointestinal polyposis and cancer. Hyperactivation of mTOR-signaling has been associated with PJS. We previously reported that rapamycin treatment of Lkb1(+/-) mice after the onset of polyposis reduced the polyp burden. Here we evaluated the preventive efficacy of rapamycin on Peutz-Jeghers polyposis. We found that rapamycin treatment of Lkb1(+/-) mice initiated before the onset of polyposis in Lkb1(+/-) mice led to a dramatic reduction in both polyp burden and polyp size and this reduction was associated with decreased phosphorylation levels of S6 and 4EBP1. Together, these findings support the use of rapamycin as an option for chemoprevention and treatment of PJS.
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Affiliation(s)
- Chongjuan Wei
- Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, 1155 Pressler Boulevard, Houston, TX 77030, USA
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48
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Sola E, Vega E, Gutiérrez C, López V, Cabello M, Burgos D, González Molina M, Siles J. [Disease by CMV resistant to Ganciclovir. Should plasma valganciclovir levels be monitored in high risk patients?]. Nefrologia 2009; 29:180-181. [PMID: 19396331 DOI: 10.3265/nefrologia.2009.29.2.4889.en.full] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
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49
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Abstract
Ethanolamine kinase 2 (Eki2) was previously isolated from a differential expression screen designed to identify candidate genes involved in testis development and differentiation. In mouse, Eki2 is specifically up-regulated in Sertoli cells of the developing testis at the time of sex determination. Based on this expression profile, Eki2 was considered a good candidate testis-determining gene. To investigate a possible role of Eki2 in testis development, we have generated a mouse with targeted disruption of the Eki2 gene by using an EGFP replacement strategy. No abnormalities were detected in the Eki2-deficient mice with regard to embryonic and adult testis morphology, differentiation, function, or fertility. Furthermore, no significant differences were observed in litter sizes, pup mortality rates, or distribution of the sexes among the offspring. Ethanolamine kinases are involved in the biosynthesis of phosphatidylethanolamine, a major membrane phospholipid. Expression analysis indicates that the absence of an apparent phenotype in the Eki2-deficient mice may be due to compensation by Eki2-family members or the activation of an alternative pathway to generate phosphatidylethanolamine. Expression of EGFP in this mouse model enabled the isolation of gonad cell populations, providing a useful resource from which to obtain relatively pure early steroidogenic cells for further studies.
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Affiliation(s)
- Sonja E Gustin
- Murdoch Children's Research Institute, University of Melbourne, Royal Children's Hospital, Melbourne, Victoria 3052, Australia
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50
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Ischebeck T, Stenzel I, Heilmann I. Type B phosphatidylinositol-4-phosphate 5-kinases mediate Arabidopsis and Nicotiana tabacum pollen tube growth by regulating apical pectin secretion. Plant Cell 2008; 20:3312-30. [PMID: 19060112 PMCID: PMC2630452 DOI: 10.1105/tpc.108.059568] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 11/13/2008] [Accepted: 11/21/2008] [Indexed: 05/18/2023]
Abstract
Phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P(2)] occurs in the apical plasma membrane of growing pollen tubes. Because enzymes responsible for PtdIns(4,5)P(2) production at that location are uncharacterized, functions of PtdIns(4,5)P(2) in pollen tube tip growth are unresolved. Two candidate genes encoding pollen-expressed Arabidopsis thaliana phosphatidylinositol-4-phosphate 5-kinases (PI4P 5-kinases) of Arabidopsis subfamily B were identified (PIP5K4 and PIP5K5), and their recombinant proteins were characterized as being PI4P 5-kinases. Pollen of T-DNA insertion lines deficient in both PIP5K4 and PIP5K5 exhibited reduced pollen germination and defects in pollen tube elongation. Fluorescence-tagged PIP5K4 and PIP5K5 localized to an apical plasma membrane microdomain in Arabidopsis and tobacco (Nicotiana tabacum) pollen tubes, and overexpression of either PIP5K4 or PIP5K5 triggered multiple tip branching events. Further studies using the tobacco system revealed that overexpression caused massive apical pectin deposition accompanied by plasma membrane invaginations. By contrast, callose deposition and cytoskeletal structures were unaltered in the overexpressors. Morphological effects depended on PtdIns(4,5)P(2) production, as an inactive enzyme variant did not produce any effects. The data indicate that excessive PtdIns(4,5)P(2) production by type B PI4P 5-kinases disturbs the balance of membrane trafficking and apical pectin deposition. Polar tip growth of pollen tubes may thus be modulated by PtdIns(4,5)P(2) via regulatory effects on membrane trafficking and/or apical pectin deposition.
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Affiliation(s)
- Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37077 Göttingen, Germany
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