Munthe-Fog L.,Laboratory of Molecular Medicine |
Hummelshoj T.,Laboratory of Molecular Medicine |
Honore C.,Laboratory of Molecular Medicine |
Moller M.E.,Laboratory of Molecular Medicine |
And 5 more authors.
Genes and Immunity | Year: 2012
Ficolin-1 is a recognition molecule of the lectin complement pathway. The ficolin-1 gene FCN1 is polymorphic, but the functional and clinical consequences are unknown.The concentration of ficolin-1 in plasma and FCN1 polymorphisms in positions 1981 (rs2989727), 791 (rs28909068), 542 (rs10120023), 271 (rs28909976), 144 (rs10117466) and 7918 (rs1071583) were determined in 100 healthy individuals. FCN1 expression by isolated monocytes and granulocytes and ficolin-1 levels in monocyte culture supernatants were assessed in 21 FCN1-genotyped individuals. FCN1 polymorphisms were determined in a cohort of 251 patients with systemic inflammation. High ficolin-1 plasma levels were significantly associated with the minor alleles in position 542 and 144. These alleles were also significantly associated with high FCN1 mRNA expression. The level of ficolin-1 in culture supernatants was significantly higher in individuals homozygous for the minor alleles at positions 542 and 144. Homozygosity for these alleles was significantly associated with fatal outcome in patients with systemic inflammation. None of the other investigated polymorphisms were associated with FCN1 and ficolin-1 expression, concentration or disease outcome. Functional polymorphic sites in the promoter region of FCN1 regulate both the expression and synthesis of ficolin-1 and are associated with outcome in severe inflammation. © 2012 Macmillan Publishers Limited. All rights reserved.
Xu M.-J.,U.S. National Institutes of Health |
Xu M.-J.,Peking University |
Feng D.,U.S. National Institutes of Health |
Wu H.,Shanghai JiaoTong University |
And 11 more authors.
Hepatology | Year: 2015
Lipocalin-2 (LCN2) was originally isolated from human neutrophils and termed neutrophil gelatinase-associated lipocalin (NGAL). However, the functions of LCN2 and the cell types that are primarily responsible for LCN2 production remain unclear. To address these issues, hepatocyte-specific Lcn2 knockout (Lcn2Hep-/-) mice were generated and subjected to bacterial infection (with Klesbsiella pneumoniae or Escherichia coli) or partial hepatectomy (PHx). Studies of Lcn2Hep-/- mice revealed that hepatocytes contributed to 25% of the low basal serum level of LCN2 protein (∼62 ng/mL) but were responsible for more than 90% of the highly elevated serum LCN2 protein level (∼6,000 ng/mL) postinfection and more than 60% post-PHx (∼700 ng/mL). Interestingly, both Lcn2Hep-/- and global Lcn2 knockout (Lcn2-/-) mice demonstrated comparable increases in susceptibility to infection with K. pneumoniae or E. coli. These mice also had increased enteric bacterial translocation from the gut to the mesenteric lymph nodes and exhibited reduced liver regeneration after PHx. Treatment with interleukin (IL)-6 stimulated hepatocytes to produce LCN2 in vitro and in vivo. Hepatocyte-specific ablation of the IL-6 receptor or Stat3, a major downstream effector of IL-6, markedly abrogated LCN2 elevation in vivo. Furthermore, chromatin immunoprecipitation (ChIP) assay revealed that STAT3 was recruited to the promoter region of the Lcn2 gene upon STAT3 activation by IL-6. Conclusion: Hepatocytes are the major cell type responsible for LCN2 production after bacterial infection or PHx, and this response is dependent on IL-6 activation of the STAT3 signaling pathway. Thus, hepatocyte-derived LCN2 plays an important role in inhibiting bacterial infection and promoting liver regeneration. © 2014 by the American Association for the Study of Liver Diseases. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
Wu H.,Rigshospitalet |
Santoni-Rugiu E.,Rigshospitalet |
Ralfkiaer E.,Rigshospitalet |
Porse B.T.,Copenhagen University |
And 4 more authors.
Respiratory Research | Year: 2010
Background: Lipocalin 2 is a bacteriostatic protein that binds the siderophore enterobactin, an iron-chelating molecule produced by Escherichia coli (E. coli) that is required for bacterial growth. Infection of the lungs by E. coli is rare despite a frequent exposure to this commensal bacterium. Lipocalin 2 is an effector molecule of the innate immune system and could therefore play a role in hindering growth of E. coli in the lungs.Methods: Lipocalin 2 knock-out and wild type mice were infected with two strains of E. coli. The lungs were removed 48 hours post-infection and examined for lipocalin 2 and MMP9 (a myeloid marker protein) by immunohistochemical staining and western blotting. Bacterial numbers were assessed in the lungs of the mice at 2 and 5 days after infection and mortality of the mice was monitored over a five-day period. The effect of administering ferrichrome (an iron source that cannot be bound by lipocalin 2) along with E.coli was also examined.Results: Intratracheal installation of E. coli in mice resulted in strong induction of lipocalin 2 expression in bronchial epithelium and alveolar type II pneumocytes. Migration of myeloid cells to the site of infection also contributed to an increased lipocalin 2 level in the lungs. Significant higher bacterial numbers were observed in the lungs of lipocalin 2 knock-out mice on days 2 and 5 after infection with E. coli (p < 0.05). In addition, a higher number of E. coli was found in the spleen of surviving lipocalin 2 knock-out mice on day 5 post-infection than in the corresponding wild-type mice (p < 0.05). The protective effect against E. coli infection in wild type mice could be counteracted by the siderophore ferrichrome, indicating that the protective effect of lipocalin 2 depends on its ability to sequester iron.Conclusions: Lipocalin 2 is important for protection of airways against infection by E. coli. © 2010 Wu et al; licensee BioMed Central Ltd.
Clemmensen S.N.,Granulocyte Research Laboratory |
Bohr C.T.,Granulocyte Research Laboratory |
Rlrvig S.,Granulocyte Research Laboratory |
Glenthlj A.,Granulocyte Research Laboratory |
And 10 more authors.
Journal of Leukocyte Biology | Year: 2012
OLFM4 was identified initially as a gene highly induced in myeloid stem cells by G-CSF treatment. A bioinformatics method using a global meta-analysis of microarray data predicted that OLFM4 would be associated with specific granules in human neutrophils. Subcellular fractionation of peripheral blood neutrophils demonstrated complete colocalization of OLFM4 with the specific granule protein NGAL, and stimulation of neutrophils with PMA resulted in corelease of NGAL and OLFM4, proving that OLFM4 is a genuine constituent of neutrophil-specific granules. In accordance with this, OLFM4 mRNA peaked at the MY/MM stage of maturation. OLFM4 was, however, present in only 20-25% of peripheral blood neutrophils, as determined by immunocytochemistry and flow cytometry, whereas mRNA for OLFM4 was present in all MY/MM, indicating post-transcriptional regulation as a basis for the heterogeneous expression of OLFM4 protein. © Society for Leukocyte Biology.
Hager M.,Granulocyte Research Laboratory |
Pedersen C.C.,Granulocyte Research Laboratory |
Larsen M.T.,Granulocyte Research Laboratory |
Andersen M.K.,Cytogenetic Laboratory |
And 5 more authors.
Blood | Year: 2011
Smad4 is important in the TGF-β pathway and required for transcriptional activation and inhibition of cell growth after TGF-β1 stimulation. We demonstrate that miR-130a is differentially expressed during granulopoiesis and targets Smad4 mRNA. The transcript for Smad4 is present throughout neutrophil maturation, but Smad4 protein is undetectable in the most immature cells, where miR-130a is highly expressed. Two miR-130a binding sites were identified in the 3′-untranslated region of the Smad4 mRNA. Overexpression of miR-130a in HEK293, A549, and 32Dcl3 cells repressed synthesis of Smad4 protein without affecting Smad4 mRNA level. Repression of Smad4 synthesis in a granulocytic cell line by miR-130a reduced its sensitivity to TGF-β1-induced growth inhibition. This effect was reversed by inhibiting the activity of miR-130a with an antisense probe or by expressing a Smad4 mRNA lacking miR-130a binding sites. High endogenous miR-130a and Smad4 mRNA levels and low expression of Smad4 protein were found in the t(8;21)(q22;q22) acute myelogenous leukemia-derived cell line Kasumi-1. When miR-130a was inhibited by an antisense RNA, the amount of Smad4 protein increased in Kasumi-1 cells and rendered it susceptible for TGF-β1-mediated cell growth inhibition. Our data indicate that miR-130a is involved in cell cycle regulation of granulocytic cells through engagement of Smad4 in the TGF-β pathway. © 2011 by The American Society of Hematology.