T HIF-1 stabilization in combination with Lcn2 is sufficient for IL-6 secretion, linking HIF-1 -regulated genes with inflammatory pathways. HIF-1 stabilization in combination with Lcn2 will not be enough to induce IL-8 or CCL20 secretion, suggesting that more pathways are activated in response to siderophore-Lcn2 stimulation that improve inflammation. IL-8 production by epithelial cells is regulated by a mixture of MAPK and NF- B signaling pathways (18). Microarray evaluation in response to remedy with Ent indicated upregulation of dual-specificity phosphatases (DUSPs), indicating that MAPK signaling is involved in IL-8 secretion in response to siderophore-Lcn2. In summary, our results introduce a novel role for Lcn2 as a rheostat that modulates the response to iron chelation by bacterial siderophores. We propose a model in which a compact quantity of Ent is often bound and neutralized by Lcn2 (Fig. 7A), resulting in low levels of Lcn2-induced cytokine secretion. Even so, high levels ofEnt (Fig. 7B) or Ybt (Fig. 7C) can overwhelm Lcn2 binding capacity, causing the accumulation of unbound siderophores. These siderophores chelate host cellular iron and, in mixture with Lcn2, induce robust secretion of IL-6, CCL20, and IL-8 in airway epithelial cells. Ent induces HIF-1 stabilization, and HIF-1 in mixture with Lcn2 is sufficient to induce IL-6. In contrast, HIF-independent pathways probably are expected to augment IL-8 and CCL20 expression. DFO and Ybt also combine with Lcn2 to induce inflammation, indicating this is a generalized response to siderophore-mediated iron starvation. In this way, Lcn2 can protect against iron sequestration by Ent without triggering a substantial Factor Xa Purity & Documentation immune response but can potently upregulate inflammation when overwhelmed by siderophores that perturb epithelial cell iron homeostasis.ACKNOWLEDGMENTSThis study was supported by Public Overall health Service grant GM085612 in the National Institute of General Healthcare CETP MedChemExpress Sciences (M.A.B.), CA148828 in the National Cancer Institute (Y.M.S.), and a University of Michigan Rackham predoctoral grant (V.I.H.), and it was partially supported byiai.asm.orgInfection and ImmunitySiderophores with Lcn2 Induce Cytokine SecretionUniversity of Michigan Cancer Center Help grant P30 CA046592 from the National Institutes of Overall health (R.K.). We thank Harry Mobley, Marc Hershenson, and Beth Moore for guidance and manuscript revisions. We’ve got no conflicting monetary interests to report.
ResearchAuthor’s Decision?2014 by The American Society for Biochemistry and Molecular Biology, Inc. This paper is available on line at mcponline.orgProteomic Evaluation of Altered Extracellular Matrix Turnover in Bleomycin-induced Pulmonary FibrosisSMartin L. Decaris, Michelle Gatmaitan, Simplicia FlorCruz, Flora Luo, Kelvin Li, William E. Holmes, Marc K. Hellerstein? Scott M. Turner, and Claire L. EmsonFibrotic disease is characterized by the pathological accumulation of extracellular matrix (ECM) proteins. Surprisingly, extremely tiny is known regarding the synthesis and degradation rates in the a lot of proteins and proteoglycans that constitute healthier or pathological extracellular matrix. A comprehensive understanding of altered ECM protein synthesis and degradation in the course of the onset and progression of fibrotic disease could be immensely important. We’ve got developed a dynamic proteomics platform that quantifies the fractional synthesis rates of large numbers of proteins through steady isotope labeling and LC/MS-based mass iso.