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Wang Z, Wang P, Zhang J, Gong H, Zhang X, Song J, Nie L, Peng Y, Li Y, Peng H, Cui Y, Li H, Hu B, Mi J, Liang L, Liu H, Zhang J, Ye M, Yazdanbakhsh K, Mohandas N, An X, Han X, Liu J. The novel GATA1-interacting protein HES6 is an essential transcriptional cofactor for human erythropoiesis. Nucleic Acids Res 2023; 51:4774-4790. [PMID: 36929421 PMCID: PMC10250228 DOI: 10.1093/nar/gkad167] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 02/21/2023] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
Normal erythropoiesis requires the precise regulation of gene expression patterns, and transcription cofactors play a vital role in this process. Deregulation of cofactors has emerged as a key mechanism contributing to erythroid disorders. Through gene expression profiling, we found HES6 as an abundant cofactor expressed at gene level during human erythropoiesis. HES6 physically interacted with GATA1 and influenced the interaction of GATA1 with FOG1. Knockdown of HES6 impaired human erythropoiesis by decreasing GATA1 expression. Chromatin immunoprecipitation and RNA sequencing revealed a rich set of HES6- and GATA1-co-regulated genes involved in erythroid-related pathways. We also discovered a positive feedback loop composed of HES6, GATA1 and STAT1 in the regulation of erythropoiesis. Notably, erythropoietin (EPO) stimulation led to up-regulation of these loop components. Increased expression levels of loop components were observed in CD34+ cells of polycythemia vera patients. Interference by either HES6 knockdown or inhibition of STAT1 activity suppressed proliferation of erythroid cells with the JAK2V617F mutation. We further explored the impact of HES6 on polycythemia vera phenotypes in mice. The identification of the HES6-GATA1 regulatory loop and its regulation by EPO provides novel insights into human erythropoiesis regulated by EPO/EPOR and a potential therapeutic target for the management of polycythemia vera.
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Affiliation(s)
- Zi Wang
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Pan Wang
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Jieying Zhang
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
- Basic Medical Institute; Hongqiao International Institute of Medicine, Tongren Hospital; Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Han Gong
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Xuchao Zhang
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Jianhui Song
- Xiangya Hospital, Central South University, Changsha 410008, China
| | - Ling Nie
- Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yuanliang Peng
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Yanan Li
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Hongling Peng
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Yajuan Cui
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Heng Li
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Bin Hu
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Jun Mi
- Basic Medical Institute; Hongqiao International Institute of Medicine, Tongren Hospital; Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Long Liang
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Hong Liu
- Xiangya Hospital, Central South University, Changsha 410008, China
| | - Ji Zhang
- Department of Clinical Laboratory, the First Affiliated Hospital, University of South China, Hengyang 421001, China
| | - Mao Ye
- Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics; College of Biology; College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | | | - Narla Mohandas
- Red Cell Physiology Laboratory, NY Blood Center, NY 10065, USA
| | - Xiuli An
- Laboratory of Membrane Biology, NY Blood Center, NY 10065, USA
| | - Xu Han
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
| | - Jing Liu
- Department of Hematology, The Second Xiangya Hospital of Central South University; Molecular Biology Research Center, Center for Medical Genetics, School of Life Sciences; Hunan Province Key Laboratory of Basic and Applied Hematology, Central South University, Changsha 410011, China
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Elabd C, Ichim TE, Miller K, Anneling A, Grinstein V, Vargas V, Silva FJ. Comparing atmospheric and hypoxic cultured mesenchymal stem cell transcriptome: implication for stem cell therapies targeting intervertebral discs. J Transl Med 2018; 16:222. [PMID: 30097061 PMCID: PMC6086019 DOI: 10.1186/s12967-018-1601-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/04/2018] [Indexed: 02/07/2023] Open
Abstract
Background Mesenchymal stem cells (MSCs) represent an attractive avenue for cellular therapies targeting degenerative diseases. MSC in vitro expansion is required in order to obtain therapeutic numbers during the manufacturing process. It is known that culture conditions impact cellular properties and behavior after in vivo transplantation. In this study, we aimed at evaluating the benefit of hypoxic culturing of human bone marrow derived mesenchymal stem cells on cell fitness and whole genome expression and discussed its implication on cellular therapies targeting orthopedic diseases such as chronic lower back pain. Methods Human bone marrow mesenchymal stem cells (hBMMSCs) were isolated from fresh human anticoagulated whole bone marrow and were cultured side by side in atmospheric (20% O2) and hypoxic (5% O2) oxygen partial pressure for up to 3 passages. Stem cell fitness was assessed by clonogenic assay, cell surface marker expression and differentiation potential. Whole genome expression was performed by mRNA sequencing. Data from clonogenic assays, cell surface marker by flow cytometry and gene expression by quantitative PCR were analyzed by two-tailed paired Student’s t-test. Data from mRNA sequencing were aligned to hg19 using Tophat-2.0.13 and analyzed using Cufflinks-2.1.1. Results Hypoxic culturing of hBMMSCs had positive effects on cell fitness, as evidenced by an increased clonogenicity and improved differentiation potential towards adipocyte and chondrocyte lineages. No difference in osteoblast differentiation or in cell surface markers were observed. Only a small subset of genes (34) were identified by mRNA sequencing to be significantly dysregulated by hypoxia. When clustered by biological function, these genes were associated with chondrogenesis and cartilage metabolism, inflammation and immunomodulation, cellular survival, migration and proliferation, vasculogenesis and angiogenesis. Conclusions Hypoxic culturing positively impacted hBMMSCs fitness and transcriptome, potentially improving inherent properties of these cells that are critical for the development of successful cellular therapies. Hypoxic culturing should be considered for the in vitro expansion of hBMMSCs during manufacturing of cellular therapies targeting orthopedic disorders such as lower back pain.
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Affiliation(s)
- C Elabd
- BioRestorative Therapies, Inc., 40 Marcus Drive, Suite 1, Melville, NY, 11747, USA
| | - T E Ichim
- Immune Advisors, LLC, La Jolla, CA, 92037, USA
| | - K Miller
- BioRestorative Therapies, Inc., 40 Marcus Drive, Suite 1, Melville, NY, 11747, USA
| | - A Anneling
- BioRestorative Therapies, Inc., 40 Marcus Drive, Suite 1, Melville, NY, 11747, USA
| | - V Grinstein
- BioRestorative Therapies, Inc., 40 Marcus Drive, Suite 1, Melville, NY, 11747, USA
| | - V Vargas
- BioRestorative Therapies, Inc., 40 Marcus Drive, Suite 1, Melville, NY, 11747, USA
| | - F J Silva
- BioRestorative Therapies, Inc., 40 Marcus Drive, Suite 1, Melville, NY, 11747, USA.
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Dual Roles of Fer Kinase Are Required for Proper Hematopoiesis and Vascular Endothelium Organization during Zebrafish Development. BIOLOGY 2017; 6:biology6040040. [PMID: 29168762 PMCID: PMC5745445 DOI: 10.3390/biology6040040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/17/2017] [Accepted: 11/18/2017] [Indexed: 11/17/2022]
Abstract
Fer kinase, a protein involved in the regulation of cell-cell adhesion and proliferation, has been shown to be required during invertebrate development and has been implicated in leukemia, gastric cancer, and liver cancer. However, in vivo roles for Fer during vertebrate development have remained elusive. In this study, we bridge the gap between the invertebrate and vertebrate realms by showing that Fer kinase is required during zebrafish embryogenesis for normal hematopoiesis and vascular organization with distinct kinase dependent and independent functions. In situ hybridization, quantitative PCR and fluorescence activated cell sorting (FACS) analyses revealed an increase in both erythrocyte numbers and gene expression patterns as well as a decrease in the organization of vasculature endothelial cells. Furthermore, rescue experiments have shown that the regulation of hematopoietic proliferation is dependent on Fer kinase activity, while vascular organizing events only require Fer in a kinase-independent manner. Our data suggest a model in which separate kinase dependent and independent functions of Fer act in conjunction with Notch activity in a divergent manner for hematopoietic determination and vascular tissue organization.
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Electroporation-mediated delivery of the FER gene in the resolution of trauma-related fatal pneumonia. Gene Ther 2016; 23:785-796. [PMID: 27454317 PMCID: PMC5096957 DOI: 10.1038/gt.2016.58] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/19/2016] [Accepted: 07/11/2016] [Indexed: 12/18/2022]
Abstract
Injured patients with lung contusion (LC) are at risk of developing bacterial pneumonia (PNA) followed by sepsis and death. A recent genome-wide association study (GWAS) showed FER gene expression positively correlating with survival rates among individuals with above conditions. We sought to determine whether electroporation (EP)-mediated delivery of FER gene could indeed improve survival, in a lethal model of combined LC and PNA. C57BL/6 mice sustained unilateral LC, which preceded a 500 Klebsiella colony forming unit (CFU) inoculation by 6 h. In-between these insults, human FER plasmid (pFER) was introduced into the lungs followed by eight EP pulses applied externally (10 ms at 200 V cm-1). Control groups included EP of empty vector (pcDNA3) or Na+/K+-ATPase genes (pPump) and no treatment (LC+PNA). We recorded survival, histology, lung mechanics, bronchial alveolar lavage (BAL) fluid, FER and inflammatory gene expression and bacteriology. The data show that 7-day survival was significantly improved by pFER compared with control groups. pFER increased BAL monocytes and activated antibacterial response genes (nitric oxide synthase (NOS), Fizz). pFER treatment showed decreased lung and blood Klebsiella counts reaching, in some cases, complete sterilization. In conclusion, FER gene delivery promoted survival in LC+PNA mice via recruitment of activated immune cells, improving efficiency of bacterial clearance within contused lung.
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Pesce M, Felaco P, Franceschelli S, Speranza L, Grilli A, De Lutiis MA, Ferrone A, Sirolli V, Bonomini M, Felaco M, Patruno A. Effect of erythropoietin on primed leucocyte expression profile. Open Biol 2014; 4:140026. [PMID: 24920275 PMCID: PMC4077059 DOI: 10.1098/rsob.140026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/20/2014] [Indexed: 02/04/2023] Open
Abstract
Resistance to erythropoietin (EPO) affects a significant number of anaemic patients with end-stage renal disease. Previous reports suggest that inflammation is one of the major independent predictors of EPO resistance, and the effects of EPO treatment on inflammatory mediators are not well established. The aim of this study was to investigate EPO-induced modification to gene expression in primary cultured leucocytes. Microarray experiments were performed on primed ex vivo peripheral blood mononuclear cells (PBMCs) and treated with human EPO-α. Data suggested that EPO-α modulated genes involved in cell movement and interaction in primed PBMCs. Of note, EPO-α exerts anti-inflammatory effects inhibiting the expression of pro-inflammatory cytokine IL-8 and its receptor CXCR2; by contrast, EPO-α increases expression of genes relating to promotion of inflammation encoding for IL-1β and CCL8, and induces de novo synthesis of IL-1α, CXCL1 and CXCL5 in primed cells. The reduction in MAPK p38-α activity is involved in modulating both IL-1β and IL-8 expression. Unlike the induction of MAPK, Erk1/2 activity leads to upregulation of IL-1β, but does not affect IL-8 expression and release. Furthermore, EPO-α treatment of primed cells induces the activation of caspase-1 upstream higher secretion of IL-1β, and this process is not dependent on caspase-8 activation. In conclusion, our findings highlight new potential molecules involved in EPO resistance and confirm the anti-inflammatory role for EPO, but also suggest a plausible in vivo scenario in which the positive correlation found between EPO resistance and elevated levels of some pro-inflammatory mediators is due to treatment with EPO itself.
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Affiliation(s)
- Mirko Pesce
- Department of Psychological, Humanistic and Territorial Sciences, University 'G. D'Annunzio', Chieti, Italy
| | - Paolo Felaco
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Sara Franceschelli
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Lorenza Speranza
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Alfredo Grilli
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Maria Anna De Lutiis
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Alessio Ferrone
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Vittorio Sirolli
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Mario Bonomini
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Mario Felaco
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
| | - Antonia Patruno
- Department of Medicine and Science of Aging, University 'G. D'Annunzio', Chieti, Italy
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Lennartsson J, Ma H, Wardega P, Pelka K, Engström U, Hellberg C, Heldin CH. The Fer tyrosine kinase is important for platelet-derived growth factor-BB-induced signal transducer and activator of transcription 3 (STAT3) protein phosphorylation, colony formation in soft agar, and tumor growth in vivo. J Biol Chem 2013; 288:15736-44. [PMID: 23589302 DOI: 10.1074/jbc.m113.476424] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Fer is a cytoplasmic tyrosine kinase that is activated in response to platelet-derived growth factor (PDGF) stimulation. In the present report, we show that Fer associates with the activated PDGF β-receptor (PDGFRβ) through multiple autophosphorylation sites, i.e. Tyr-579, Tyr-581, Tyr-740, and Tyr-1021. Using low molecular weight inhibitors, we found that PDGF-BB-induced Fer activation is dependent on PDGFRβ kinase activity, but not on the enzymatic activity of Src or Jak kinases. In cells in which Fer was down-regulated using siRNA, PDGF-BB was unable to induce phosphorylation of STAT3, whereas phosphorylations of STAT5, ERK1/2, and Akt were unaffected. PDGF-BB-induced activation of STAT3 occurred also in cells expressing kinase-dead Fer, suggesting a kinase-independent adaptor role of Fer. Expression of Fer was dispensable for PDGF-BB-induced proliferation and migration but essential for colony formation in soft agar. Tumor growth in vivo was delayed in cells depleted of Fer expression. Our data suggest a critical role of Fer in PDGF-BB-induced STAT3 activation and cell transformation.
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Affiliation(s)
- Johan Lennartsson
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Box 595, SE-75124, Uppsala, Sweden
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Fps/Fes protein-tyrosine kinase regulates mast cell adhesion and migration downstream of Kit and β1 integrin receptors. Cell Signal 2010; 22:427-36. [DOI: 10.1016/j.cellsig.2009.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 10/23/2009] [Indexed: 11/17/2022]
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Voisset E, Lopez S, Dubreuil P, De Sepulveda P. The tyrosine kinase FES is an essential effector of KITD816V proliferation signal. Blood 2007; 110:2593-9. [PMID: 17595334 DOI: 10.1182/blood-2007-02-076471] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
KIT is a tyrosine kinase receptor that is aberrantly activated in several neoplasms. In human pathologies, the most frequent mutation of KIT occurs at codon 816. The resulting KIT mutant protein is activated in the absence of ligand and is resistant to the clinically available inhibitors of KIT. In this report, we provide evidence for an essential function of the cytoplasmic tyrosine kinase FES downstream of KITD816V. FES is phosphorylated on tyrosine residues in cells that carry KITD816V mutation, and this phosphorylation is KIT dependent. Reduction of FES expression using RNA interference results in decreased cell proliferation in human or murine cells harboring KITD816V or the homologous mouse mutation KITD814Y. The reduced cell growth can be rescued using another cytokine (granulocyte-macrophage colony-stimulating factor [GM-CSF]) and is not observed when the closely related fer gene is targeted. Finally, signaling downstream of KITD816V is altered in cells lacking FES expression. This study shows a major function of FES downstream of activated KIT receptor and thereby points to FES as a novel target in KIT-related pathologies.
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Affiliation(s)
- Edwige Voisset
- Institut National de la Santé et de la Rècherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 599, Centre de Recherche en Cancérologie de Marseille, Laboratoire d'Hématopoïèse Moléculaire et Fonctionnelle, Marseille, France
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Parsons SA, Mewburn JD, Truesdell P, Greer PA. The Fps/Fes kinase regulates leucocyte recruitment and extravasation during inflammation. Immunology 2007; 122:542-50. [PMID: 17627769 PMCID: PMC2228385 DOI: 10.1111/j.1365-2567.2007.02670.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Fps/Fes and Fer comprise a distinct subfamily of cytoplasmic protein-tyrosine kinases, and have both been implicated in the regulation of innate immunity. Previous studies showed that Fps/Fes-knockout mice were hypersensitive to systemic lipopolysaccharide (LPS) challenge, and Fer-deficient mice displayed enhanced recruitment of leucocytes in response to localized LPS challenge. We show here for the first time, a role for Fps in the regulation of leucocyte recruitment to areas of inflammation. Using the cremaster muscle intravital microscopy model, we observed increased leucocyte adherence to venules, and increased rates and degrees of transendothelial migration in Fps/Fes-knockout mice relative to wild-type animals subsequent to localized LPS challenge. There was also a decreased vessel wall shear rate in the post-capillary venules of LPS-challenged Fps/Fes-knockout mice, and an increase in neutrophil migration into the peritoneal cavity subsequent to thioglycollate challenge. Using flow cytometry to quantify the expression of surface molecules, we observed prolonged expression of the selectin ligand PSGL-1 on peripheral blood neutrophils from Fps/Fes-knockout mice stimulated ex vivo with LPS. These observations provide important insights into the observed in vivo behaviour of leucocytes in LPS-challenged Fps/Fes-knockout mice and provide evidence that the Fps/Fes kinase plays an important role in the innate immune response.
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Affiliation(s)
- Sean A Parsons
- Division of Cancer Biology and Genetics, Queen's University Cancer Research Institute, Queens University, Kingston, Ontario, Canada
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Parsons SA, Greer PA. The Fps/Fes kinase regulates the inflammatory response to endotoxin through down-regulation of TLR4, NF-kappaB activation, and TNF-alpha secretion in macrophages. J Leukoc Biol 2006; 80:1522-8. [PMID: 16959897 DOI: 10.1189/jlb.0506350] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Fps/Fes and Fer are members of a distinct subfamily of cytoplasmic protein tyrosine kinases that have recently been implicated in the regulation of innate immunity. Previous studies showed that mice lacking Fps/Fes are hypersensitive to systemic LPS challenge, and Fer-deficient mice displayed enhanced recruitment of leukocytes in response to local LPS challenge. This study identifies physiological, cellular, and molecular defects that contribute to the hyperinflammatory phenotype in Fps/Fes null mice. Plasma TNF-alpha levels were elevated in LPS challenged Fps/Fes null mice as compared with wild-type mice and cultured Fps/Fes null peritoneal macrophages treated with LPS showed increased TNF-alpha production. Cultured Fps/Fes null macrophages also displayed prolonged LPS-induced degradation of IkappaB-alpha, increased phosphorylation of the p65 subunit of NF-kappaB, and defective TLR4 internalization, compared with wild-type macrophages. Together, these observations provide a likely mechanistic basis for elevated proinflammatory cytokine secretion by Fps/Fes null macrophages and the increased sensitivity of Fps/Fes null mice to endotoxin. We posit that Fps/Fes modulates the innate immune response of macrophages to LPS, in part, by regulating internalization and down-regulation of the TLR4 receptor complex.
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Affiliation(s)
- Sean A Parsons
- Division of Cancer Biology and Genetics, Botterell Hall, Room A309, Queens University, Kingston, Ontario K7L 3N6, Canada
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