1
|
Karampitsakos T, Galaris A, Chrysikos S, Papaioannou O, Vamvakaris I, Barbayianni I, Kanellopoulou P, Grammenoudi S, Anagnostopoulos N, Stratakos G, Katsaras M, Sampsonas F, Dimakou K, Manali ED, Papiris S, Tourki B, Juan-Guardela BM, Bakakos P, Bouros D, Herazo-Maya JD, Aidinis V, Tzouvelekis A. Expression of PD-1/PD-L1 axis in mediastinal lymph nodes and lung tissue of human and experimental lung fibrosis indicates a potential therapeutic target for idiopathic pulmonary fibrosis. Respir Res 2023; 24:279. [PMID: 37964265 PMCID: PMC10648728 DOI: 10.1186/s12931-023-02551-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [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: 08/31/2023] [Accepted: 10/02/2023] [Indexed: 11/16/2023] Open
Abstract
BACKGROUND Mediastinal lymph node enlargement is prevalent in patients with idiopathic pulmonary fibrosis (IPF). Studies investigating whether this phenomenon reflects specific immunologic activation are lacking. METHODS Programmed cell death-1 (PD-1)/ programmed cell death ligand-1 (PD-L1) expression in mediastinal lymph nodes and lung tissues was analyzed. PD-1, PD-L1 mRNA expression was measured in tracheobronchial lymph nodes of mice following bleomycin-induced injury on day 14. Finally, the effect of the PD-1 inhibitor, pembrolizumab, in bleomycin-induced pulmonary fibrosis was investigated. RESULTS We analyzed mediastinal lymph nodes of thirty-three patients (n = 33, IPF: n = 14, lung cancer: n = 10, concomitant IPF and lung cancer: n = 9) and lung tissues of two hundred nineteen patients (n = 219, IPF: 123, controls: 96). PD-1 expression was increased, while PD-L1 expression was decreased, in mediastinal lymph nodes of patients with IPF compared to lung cancer and in IPF lungs compared to control lungs. Tracheobronchial lymph nodes isolated on day 14 from bleomycin-treated mice exhibited increased size and higher PD-1, PD-L1 mRNA levels compared to saline-treated animals. Pembrolizumab blunted bleomycin-induced lung fibrosis, as indicated by reduction in Ashcroft score and improvement in respiratory mechanics. CONCLUSIONS Mediastinal lymph nodes of patients with IPF exhibit differential expression profiles than those of patients with lung cancer indicating distinct immune-mediated pathways regulating fibrogenesis and carcinogenesis. PD-1 expression in mediastinal lymph nodes is in line with lung tissue expression. Lower doses of pembrolizumab might exert antifibrotic effects. Clinical trials aiming to endotype patients based on mediastinal lymph node profiling and accordingly implement targeted therapies such as PD-1 inhibitors are greatly anticipated.
Collapse
Affiliation(s)
- Theodoros Karampitsakos
- Department of Respiratory Medicine, University Hospital of Patras, Rio, Greece
- Ubben Center and Laboratory for Pulmonary Fibrosis Research, Morsani College of Medicine, University of South Florida, 33620, Tampa, FL, USA
| | - Apostolos Galaris
- Institute of Bio- Innovation, Biomedical Sciences Research Center Alexander Fleming, Athens, Greece
| | - Serafeim Chrysikos
- 5th Department of Pneumonology, Hospital for Thoracic Diseases, "SOTIRIA", Athens, Greece
| | - Ourania Papaioannou
- Department of Respiratory Medicine, University Hospital of Patras, Rio, Greece
| | - Ioannis Vamvakaris
- Department of Pathology, Hospital for Thoracic Diseases, "SOTIRIA", Athens, Greece
| | - Ilianna Barbayianni
- Institute of Bio- Innovation, Biomedical Sciences Research Center Alexander Fleming, Athens, Greece
| | - Paraskevi Kanellopoulou
- Institute of Bio- Innovation, Biomedical Sciences Research Center Alexander Fleming, Athens, Greece
| | - Sofia Grammenoudi
- Institute of Bio- Innovation, Biomedical Sciences Research Center Alexander Fleming, Athens, Greece
| | - Nektarios Anagnostopoulos
- First Academic Department of Pneumonology, "SOTIRIA", Medical School, Hospital for Thoracic Diseases, National and Kapodistrian University of Athens, Athens, Greece
| | - Grigoris Stratakos
- First Academic Department of Pneumonology, "SOTIRIA", Medical School, Hospital for Thoracic Diseases, National and Kapodistrian University of Athens, Athens, Greece
| | - Matthaios Katsaras
- Department of Respiratory Medicine, University Hospital of Patras, Rio, Greece
| | - Fotios Sampsonas
- Department of Respiratory Medicine, University Hospital of Patras, Rio, Greece
| | - Katerina Dimakou
- 5th Department of Pneumonology, Hospital for Thoracic Diseases, "SOTIRIA", Athens, Greece
| | - Effrosyni D Manali
- 2nd Pulmonary Medicine Department, Athens Medical School, "ATTIKON" University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Spyridon Papiris
- 2nd Pulmonary Medicine Department, Athens Medical School, "ATTIKON" University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Bochra Tourki
- Ubben Center and Laboratory for Pulmonary Fibrosis Research, Morsani College of Medicine, University of South Florida, 33620, Tampa, FL, USA
| | - Brenda M Juan-Guardela
- Ubben Center and Laboratory for Pulmonary Fibrosis Research, Morsani College of Medicine, University of South Florida, 33620, Tampa, FL, USA
| | - Petros Bakakos
- First Academic Department of Pneumonology, "SOTIRIA", Medical School, Hospital for Thoracic Diseases, National and Kapodistrian University of Athens, Athens, Greece
| | - Demosthenes Bouros
- First Academic Department of Pneumonology, "SOTIRIA", Medical School, Hospital for Thoracic Diseases, National and Kapodistrian University of Athens, Athens, Greece
| | - Jose D Herazo-Maya
- Ubben Center and Laboratory for Pulmonary Fibrosis Research, Morsani College of Medicine, University of South Florida, 33620, Tampa, FL, USA
| | - Vassilis Aidinis
- Institute of Bio- Innovation, Biomedical Sciences Research Center Alexander Fleming, Athens, Greece
| | - Argyris Tzouvelekis
- Department of Respiratory Medicine, University Hospital of Patras, Rio, Greece.
| |
Collapse
|
2
|
Voutyraki C, Choromidis A, Meligkounaki A, Vlachopoulos NA, Theodorou V, Grammenoudi S, Athanasiadis E, Monticelli S, Giangrande A, Delidakis C, Zacharioudaki E. Growth deregulation and interaction with host hemocytes contribute to tumor progression in a Drosophila brain tumor model. Proc Natl Acad Sci U S A 2023; 120:e2221601120. [PMID: 37549261 PMCID: PMC10438840 DOI: 10.1073/pnas.2221601120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 12/23/2022] [Accepted: 06/27/2023] [Indexed: 08/09/2023] Open
Abstract
Tumors constantly interact with their microenvironment. Here, we present data on a Notch-induced neural stem cell (NSC) tumor in Drosophila, which can be immortalized by serial transplantation in adult hosts. This tumor arises in the larva by virtue of the ability of Notch to suppress early differentiation-promoting factors in NSC progeny. Guided by transcriptome data, we have addressed both tumor-intrinsic and microenvironment-specific factors and how they contribute to tumor growth and host demise. The growth promoting factors Myc, Imp, and Insulin receptor in the tumor cells are important for tumor expansion and killing of the host. From the host's side, hemocytes, professional phagocytic blood cells, are found associated with tumor cells. Phagocytic receptors, like NimC1, are needed in hemocytes to enable them to capture and engulf tumor cells, restricting their growth. In addition to their protective role, hemocytes may also increase the host's morbidity by their propensity to produce damaging extracellular reactive oxygen species.
Collapse
Affiliation(s)
- Chrysanthi Voutyraki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
- Department of Biology, University of Crete, 70013Heraklion, Crete, Greece
| | - Alexandros Choromidis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
- Department of Biology, University of Crete, 70013Heraklion, Crete, Greece
| | - Anastasia Meligkounaki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
- Department of Biology, University of Crete, 70013Heraklion, Crete, Greece
| | - Nikolaos Andreas Vlachopoulos
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
- Department of Biology, University of Crete, 70013Heraklion, Crete, Greece
| | - Vasiliki Theodorou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
| | - Sofia Grammenoudi
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center Alexander Fleming, 16672Athens, Greece
| | - Emmanouil Athanasiadis
- Greek Genome Centre, Biomedical Research Foundation of the Academy of Athens, 11527Athens, Greece
- Medical Image and Signal Processing Laboratory, Department of Biomedical Engineering, University of West Attica, 12243Athens, Greece
| | - Sara Monticelli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67400Strasbourg, France
- Centre National de la Recherche Scientifique, UMR7104Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale, U1258Strasbourg, France
- Université de Strasbourg, 67404Strasbourg, France
| | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67400Strasbourg, France
- Centre National de la Recherche Scientifique, UMR7104Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale, U1258Strasbourg, France
- Université de Strasbourg, 67404Strasbourg, France
| | - Christos Delidakis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
- Department of Biology, University of Crete, 70013Heraklion, Crete, Greece
| | - Evanthia Zacharioudaki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013Heraklion, Crete, Greece
| |
Collapse
|
3
|
Voutyraki C, Choromidis A, Theodorou V, Efraimoglou C, Anagnostopoulos G, Magadi SS, Grammenoudi S, Zacharioudaki E, Delidakis C. Repression of differentiation genes by Hes transcription factors fuels neural tumour growth in Drosophila. Int J Dev Biol 2022; 66:211-222. [PMID: 34881794 DOI: 10.1387/ijdb.210187cd] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
BACKGROUND Neural stem cells (NSC) in divide asymmetrically to generate one cell that retains stem cell identity and another that is routed to differentiation. Prolonged mitotic activity of the NSCs gives rise to the plethora of neurons and glial cells that wire the brain and nerve cord. Genetic insults, such as excess of Notch signaling, perturb the normal NSC proliferation programs and trigger the formation of NSC hyperplasias, which can subsequently progress to malignancies. Hes proteins are crucial mediators of Notch signaling, and in the NSC context they act by repressing a cohort of early pro-differentiation transcription factors. Downregulation of these pro-differentiation factors makes NSC progeny cells susceptible to adopting an aberrant stem cell program. We have recently shown that Hes overexpression in Drosophila leads to NSC hyperplasias that progress to malignant tumours after allografting to adult hosts. METHODS We have combined genetic analysis, tissue allografting and transcriptomic approaches to address the role of Hes genes in NSC malignant transformation. RESULTS We show that the E (spl) genes are important mediators in the progression of Notch hyperplasias to malignancy, since allografts lacking the E (spl) genes grow much more slowly. We further present RNA profiling of Hes-induced tumours at two different stages after allografting. We find that the same cohort of differentiation-promoting transcription factors that are repressed in the primary hyperplasias continue to be downregulated after transplantation. This is accompanied by an upregulation of stress-response genes and metabolic reprogramming. CONCLUSIONS The combination of dedifferentiation and cell physiology changes most likely drive tumour growth.
Collapse
Affiliation(s)
- Chrysanthi Voutyraki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Alexandros Choromidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Vasiliki Theodorou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Christina Efraimoglou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Gerasimos Anagnostopoulos
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Srivathsa S Magadi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Sofia Grammenoudi
- Institute for Genome Stability in Ageing and Disease, Medical Faculty and Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases, Center for Molecular Medicine Cologne, University of Cologne, Germany
| | - Evanthia Zacharioudaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Christos Delidakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| |
Collapse
|
4
|
Gioulbasani M, Galaras A, Grammenoudi S, Moulos P, Dent AL, Sigvardsson M, Hatzis P, Kee BL, Verykokakis M. The transcription factor BCL-6 controls early development of innate-like T cells. Nat Immunol 2020; 21:1058-1069. [PMID: 32719520 PMCID: PMC7442690 DOI: 10.1038/s41590-020-0737-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 06/15/2020] [Indexed: 12/21/2022]
Abstract
Innate T cells, including invariant natural killer T (iNKT) and mucosal-associated innate T (MAIT) cells, are a heterogeneous T lymphocyte population with effector properties pre-programmed during their thymic differentiation. How this program is initiated is currently unclear. Here, we show that the transcription factor BCL-6 was transiently expressed in iNKT cells upon exit from positive selection and was required for their proper development beyond stage 0. Notably, development of MAIT cells was also impaired in the absence of Bcl6. BCL-6–deficient iNKT cells had reduced expression of genes that were associated with the innate T cell lineage, including Zbtb16, which encodes PLZF, and PLZF-targeted genes. BCL-6 contributed to a chromatin accessibility landscape that was permissive for the expression of development-related genes and inhibitory for genes associated with naïve T cell programs. Our results revealed novel functions for BCL-6 and illuminated how this transcription factor controls early iNKT cell development.
Collapse
Affiliation(s)
| | - Alexandros Galaras
- Institute for Fundamental Biomedical Research, BSRC Alexander Fleming, Vari, Greece.,Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, Greece
| | - Sofia Grammenoudi
- Institute for Fundamental Biomedical Research, BSRC Alexander Fleming, Vari, Greece
| | - Panagiotis Moulos
- Institute for Fundamental Biomedical Research, BSRC Alexander Fleming, Vari, Greece
| | - Alexander L Dent
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Mikael Sigvardsson
- Department of Clinical and Experimental Medicine, Experimental Hematopoiesis Unit, Faculty for Health Sciences, Linköping University, Linköping, Sweden
| | - Pantelis Hatzis
- Institute for Fundamental Biomedical Research, BSRC Alexander Fleming, Vari, Greece
| | - Barbara L Kee
- Department of Pathology and Committee on Immunology, University of Chicago, Chicago, IL, USA.
| | - Mihalis Verykokakis
- Institute for Fundamental Biomedical Research, BSRC Alexander Fleming, Vari, Greece.
| |
Collapse
|
5
|
Papanikolopoulou K, Grammenoudi S, Samiotaki M, Skoulakis EMC. Differential effects of 14-3-3 dimers on Tau phosphorylation, stability and toxicity in vivo. Hum Mol Genet 2019; 27:2244-2261. [PMID: 29659825 DOI: 10.1093/hmg/ddy129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/06/2018] [Indexed: 01/09/2023] Open
Abstract
Neurodegenerative dementias collectively known as Tauopathies involve aberrant phosphorylation and aggregation of the neuronal protein Tau. The largely neuronal 14-3-3 proteins are also elevated in the central nervous system (CNS) and cerebrospinal fluid of Tauopathy patients, suggesting functional linkage. We use the simplicity and genetic facility of the Drosophila system to investigate in vivo whether 14-3-3s are causal or synergistic with Tau accumulation in precipitating pathogenesis. Proteomic, biochemical and genetic evidence demonstrate that both Drosophila 14-3-3 proteins interact with human wild-type and mutant Tau on multiple sites irrespective of their phosphorylation state. 14-3-3 dimers regulate steady-state phosphorylation of both wild-type and the R406W mutant Tau, but they are not essential for toxicity of either variant. Moreover, 14-3-3 elevation itself is not pathogenic, but recruitment of dimers on accumulating wild-type Tau increases its steady-state levels ostensibly by occluding access to proteases in a phosphorylation-dependent manner. In contrast, the R406W mutant, which lacks a putative 14-3-3 binding site, responds differentially to elevation of each 14-3-3 isoform. Although excess 14-3-3ζ stabilizes the mutant protein, elevated D14-3-3ɛ has a destabilizing effect probably because of altered 14-3-3 dimer composition. Our collective data demonstrate the complexity of 14-3-3/Tau interactions in vivo and suggest that 14-3-3 attenuation is not appropriate ameliorative treatment of Tauopathies. Finally, we suggest that 'bystander' 14-3-3s are recruited by accumulating Tau with the consequences depending on the composition of available dimers within particular neurons and the Tau variant.
Collapse
Affiliation(s)
- Katerina Papanikolopoulou
- Division of Neuroscience, Biomedical Sciences Research Centre 'Alexander Fleming', Vari 16672, Greece
| | - Sofia Grammenoudi
- Division of Neuroscience, Biomedical Sciences Research Centre 'Alexander Fleming', Vari 16672, Greece
| | - Martina Samiotaki
- Proteomics Facility, Biomedical Sciences Research Centre 'Alexander Fleming', Vari 16672, Greece
| | - Efthimios M C Skoulakis
- Division of Neuroscience, Biomedical Sciences Research Centre 'Alexander Fleming', Vari 16672, Greece
| |
Collapse
|
6
|
Skliris A, Papadaki O, Kafasla P, Karakasiliotis I, Hazapis O, Reczko M, Grammenoudi S, Bauer J, Kontoyiannis DL. Neuroprotection requires the functions of the RNA-binding protein HuR. Cell Death Differ 2014; 22:703-18. [PMID: 25301069 DOI: 10.1038/cdd.2014.158] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 08/17/2014] [Accepted: 09/01/2014] [Indexed: 12/14/2022] Open
Abstract
Alterations in the functions of neuronal RNA-binding proteins (RBPs) can contribute to neurodegenerative diseases. However, neurons also express a set of widely distributed RBPs that may have developed specialized functions. Here, we show that the ubiquitous member of the otherwise neuronal Elavl/Hu family of RNA-binding proteins, Elavl1/HuR, has a neuroprotective role. Mice engineered to lack exclusively HuR in the hippocampal neurons of the central nervous system (CNS), maintain physiologic levels of neuronal Elavls and develop a partially diminished seizure response following strong glutamatergic excitation; however, they display an exacerbated neurodegenerative response subsequent to the initial excitotoxic event. This response was phenocopied in hippocampal cells devoid of ionotropic glutamate receptors in which the loss of HuR results in enhanced mitochondrial dysfunction, oxidative damage and programmed necrosis solely after glutamate challenge. The molecular dissection of HuR and nElavl mRNA targets revealed the existence of a HuR-restricted posttranscriptional regulon that failed in HuR-deficient neurons and is involved in cellular energetics and oxidation defense. Thus, HuR acts as a specialized controller of oxidative metabolism in neurons to confer protection from neurodegeneration.
Collapse
Affiliation(s)
- A Skliris
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - O Papadaki
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - P Kafasla
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - I Karakasiliotis
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - O Hazapis
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - M Reczko
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - S Grammenoudi
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| | - J Bauer
- Centre for Brain Research, Medical University of Vienna, A109 Vienna, Austria
| | - D L Kontoyiannis
- Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece
| |
Collapse
|
7
|
Tsagaratou A, Grammenoudi S, Mosialos G. Differential requirement of IKK2 for CYLD-dependent representation of thymic and peripheral T-cell populations. Eur J Immunol 2011; 41:3054-62. [DOI: 10.1002/eji.201041160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 04/21/2011] [Accepted: 06/27/2011] [Indexed: 01/09/2023]
|
8
|
Tsagaratou A, Trompouki E, Grammenoudi S, Kontoyiannis DL, Mosialos G. Thymocyte-Specific Truncation of the Deubiquitinating Domain of CYLD Impairs Positive Selection in a NF-κB Essential Modulator-Dependent Manner. J I 2010; 185:2032-43. [DOI: 10.4049/jimmunol.0903919] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
9
|
Abstract
Members of the conserved 14-3-3 protein family spontaneously self-assemble as homo- and heterodimers via conserved sequences in the first four (alphaA-alphaD) of the nine helices that comprise them. Dimeric 14-3-3s bind conserved motifs in diverse protein targets involved in multiple essential cellular processes including signaling, intracellular trafficking, cell cycle regulation, and modulation of enzymatic activities. However, recent mostly in vitro evidence has emerged, suggesting functional and regulatory roles for monomeric 14-3-3s. We capitalized on the simplicity of the 14-3-3 family in Drosophila to investigate in vivo 14-3-3zeta monomer properties and functionality. We report that dimerization is essential for the stability and function of 14-3-3zeta in neurons. Moreover, we reveal the contribution of conserved amino acids in helices A and D to homo- and heterodimerization and their functional consequences on the viability of animals devoid of endogenous 14-3-3zeta. Finally, we present evidence suggesting endogenous homeostatic adjustment of the levels of the second family member in Drosophila, D14-3-3epsilon, to transgenic monomeric and dimerization-competent 14-3-3zeta.
Collapse
Affiliation(s)
- Georgia Messaritou
- Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre, Alexander Fleming, Vari 16672, Greece
| | | | | |
Collapse
|
10
|
Papadaki O, Milatos S, Grammenoudi S, Mukherjee N, Keene JD, Kontoyiannis DL. Control of thymic T cell maturation, deletion and egress by the RNA-binding protein HuR. J Immunol 2009; 182:6779-88. [PMID: 19454673 DOI: 10.4049/jimmunol.0900377] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HuR emerged as a posttranscriptional regulator of mRNAs involved in cellular control, stress, and immunity but its role in governing such responses remains elusive. In this study, we assessed HuR's role in the staged progression of thymic T cell differentiation by means of its genetic ablation. Mice with an early deletion of HuR in thymocytes possess enlarged thymi but display a substantial loss of peripheral T cells. We show that this discordant phenotype related to specific defects in thymic cellular processes, which demonstrated HuR's involvement in: 1) intrinsic checkpoint signals suppressing the cell cycle of immature thymocyte progenitors, 2) TCR and antigenic signals promoting the activation and positive selection of mature thymocytes, 3) antigenic and death-receptor signals promoting thymocyte deletion, and 4) chemokine signals driving the egress of postselection thymocytes to the periphery. The cellular consequences of HuR's dysfunction were underlined by the aberrant expression of selective cell cycle regulators, TCR, and death-receptor signaling components. Our studies reveal the signal-dependent context of HuR's cellular activities in thymocytes and its importance in the generation of a physiological T cell pool.
Collapse
Affiliation(s)
- Olympia Papadaki
- Institute of Immunology, Biomedical Sciences Research Centre Alexander Fleming, Vari, Greece
| | | | | | | | | | | |
Collapse
|
11
|
Grammenoudi S, Anezaki M, Kosmidis S, Skoulakis EMC. Modelling cell and isoform type specificity of tauopathies in Drosophila. SEB Exp Biol Ser 2008; 60:39-56. [PMID: 18309786] [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: 05/26/2023]
Affiliation(s)
- Sofia Grammenoudi
- Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre Alexander Fleming, Vari, Greece
| | | | | | | |
Collapse
|
12
|
Abstract
The functional specialization or redundancy of the ubiquitous 14-3-3 proteins constitutes a fundamental question in their biology and stems from their highly conserved structure and multiplicity of coexpressed isotypes. We address this question in vivo using mutations in the two Drosophila 14-3-3 genes, leonardo (14-3-3zeta) and D14-3-3epsilon. We demonstrate that D14-3-3epsilon is essential for embryonic hatching. Nevertheless, D14-3-3epsilon null homozygotes survive because they upregulate transcripts encoding the LEOII isoform at the time of hatching, compensating D14-3-3epsilon loss. This novel homeostatic response explains the reported functional redundancy of the Drosophila 14-3-3 isotypes and survival of D14-3-3epsilon mutants. The response appears unidirectional, as D14-3-3epsilon elevation upon LEO loss was not observed and elevation of leo transcripts was stage and tissue specific. In contrast, LEO levels are not changed in the wing disks, resulting in the aberrant wing veins characterizing D14-3-3epsilon mutants. Nevertheless, conditional overexpression of LEOI, but not of LEOII, in the wing disk can partially rescue the venation deficits. Thus, excess of a particular LEO isoform can functionally compensate for D14-3-3epsilon loss in a cellular-context-specific manner. These results demonstrate functional differences both among Drosophila 14-3-3 proteins and between the two LEO isoforms in vivo, which likely underlie differential dimer affinities toward 14-3-3 targets.
Collapse
Affiliation(s)
- Summer F Acevedo
- Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre Alexander Fleming, 16672 Vari, Greece
| | | | | | | |
Collapse
|
13
|
Grammenoudi S, Kosmidis S, Skoulakis EMC. Cell type-specific processing of human Tau proteins in Drosophila. FEBS Lett 2006; 580:4602-6. [PMID: 16875690 DOI: 10.1016/j.febslet.2006.07.045] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [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: 06/07/2006] [Revised: 07/06/2006] [Accepted: 07/10/2006] [Indexed: 01/23/2023]
Abstract
Accumulation of hyperphosphorylated Tau is associated with a number of neurodegenerative diseases collectively known as tauopathies. Differences in clinical and cognitive profiles among them suggest differential sensitivity of neuronal populations to Tau levels, phosphorylation and mutations. We used tissue specific expression of wild type and mutant human tau transgenes to demonstrate differential phosphorylation and stability in a cell type-specific manner, which includes different neuronal types and does not correlate with the level of accumulated protein. Rather, they likely reflect the spatial distribution or regulation of Tau-targeting kinases and phosphatases.
Collapse
Affiliation(s)
- Sofia Grammenoudi
- Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre "Alexander Fleming", 34 Fleming Street, Vari 16672, Greece
| | | | | |
Collapse
|
14
|
Abstract
Progress towards amelioration and eventual cure of human cognitive disorders requires understanding the molecular signaling mechanisms that normally govern learning and memory. The fly Drosophila melanogaster has been instrumental in the identification of molecules and signaling pathways essential for learning and memory, because genetic screens have produced mutants in these processes and the system facilitates integrated genetic, molecular, histological and behavioral analyses. We discuss the behavioral paradigms available to assess associative learning and memory in the fly, the contributions learning and memory mutants have made to our understanding of the molecular mechanisms that govern learning and memory, and predictions stemming from the nature of the affected genes. Furthermore, we consider the multiple well-established behavioral assays available and the powerful molecular genetics of the fly with regard to development of models of human cognitive disorders and their pharmacological treatment.
Collapse
Affiliation(s)
- E M C Skoulakis
- Institute of Molecular Biology and Genetics, BSRC Alexander Fleming, 34 Fleming Str., Vari, 16672, Greece.
| | | |
Collapse
|
15
|
Tsitilou SG, Grammenoudi S. Evidence for alternative splicing and developmental regulation of the Drosophila melanogaster Mgat2 (N-acetylglucosaminyltransferase II) gene. Biochem Biophys Res Commun 2004; 312:1372-6. [PMID: 14652025 DOI: 10.1016/j.bbrc.2003.11.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a molecular study of the Drosophila melanogaster Mgat2 gene that codes for the N-acetylglucosaminyltransferase II. Isolation and analysis of two cDNA clones indicated that the gene is alternatively spliced, generating two transcripts of 3.3 and 2.7kb. Developmental specificity was observed between the two alternative transcripts during the major developmental stages of D. melanogaster. The deduced amino acid sequences of the two proteins show significant homology to the equivalent mammalian proteins, especially in the carboxyterminal region. In situ hybridizations in embryos and embryonic imaginal discs showed that the gene is expressed mainly but not exclusively in the brain.
Collapse
Affiliation(s)
- Sonia G Tsitilou
- Department of Biochemistry and Molecular Biology, University of Athens, 15701, Athens, Greece.
| | | |
Collapse
|
16
|
Delneri D, Colson I, Grammenoudi S, Roberts IN, Louis EJ, Oliver SG. Engineering evolution to study speciation in yeasts. Nature 2003; 422:68-72. [PMID: 12621434 DOI: 10.1038/nature01418] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [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: 11/21/2002] [Accepted: 12/31/2002] [Indexed: 11/08/2022]
Abstract
The Saccharomyces 'sensu stricto' yeasts are a group of species that will mate with one another, but interspecific pairings produce sterile hybrids. A retrospective analysis of their genomes revealed that translocations between the chromosomes of these species do not correlate with the group's sequence-based phylogeny (that is, translocations do not drive the process of speciation). However, that analysis was unable to infer what contribution such rearrangements make to reproductive isolation between these organisms. Here, we report experiments that take an interventionist, rather than a retrospective approach to studying speciation, by reconfiguring the Saccharomyces cerevisiae genome so that it is collinear with that of Saccharomyces mikatae. We demonstrate that this imposed genomic collinearity allows the generation of interspecific hybrids that produce a large proportion of spores that are viable, but extensively aneuploid. We obtained similar results in crosses between wild-type S. cerevisiae and the naturally collinear species Saccharomyces paradoxus, but not with non-collinear crosses. This controlled comparison of the effect of chromosomal translocation on species barriers suggests a mechanism for the generation of redundancy in the S. cerevisiae genome.
Collapse
Affiliation(s)
- Daniela Delneri
- School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, UK
| | | | | | | | | | | |
Collapse
|