scholarly journals Nramp1 locus encodes a 65 kDa interferon-γ-inducible protein in murine macrophages

1997 ◽  
Vol 325 (3) ◽  
pp. 779-786 ◽  
Author(s):  
Peter G. P. ATKINSON ◽  
Jenefer M. BLACKWELL ◽  
C. Howard BARTON
Keyword(s):  
Divalent Cation ◽  
Sequence Similarity ◽  
Iron Chelation ◽  
Interferon Γ ◽  
Natural Resistance ◽  
Protein Levels ◽  
Macrophage Cells ◽  
Protein Locus ◽  
Macrophage Protein ◽  
Inducible Protein

The murine Nramp1 (natural-resistance-associated macrophage protein) locus, formerly known as Ity/Lsh/Bcg, was isolated previously on the basis of chromosomal location, and as conferring natural resistance to infection against intracellular macrophage pathogens. The gene encodes a transporter molecule of unknown function. We have prepared polyclonal antisera against the C-terminal 35 amino acids of murine Nramp1. This serum is reactive towards a 65 kDa protein, expressed in murine macrophage cells from resistant or susceptible mice stimulated with interferon-γ and lipopolysaccharide, but not in non-macrophage cells. Evidence indicates that Nramp1 is localized in a subcellular membrane rather than at the cell surface. This evidence includes: the identification of conserved endocytic targeting motifs following inspection of human and murine Nramp sequences; the enrichment of Nramp1, following magnetic selection of phagolysosomal vesicles from activated macrophages that were allowed to phagocytose magnetic, IgG-coated beads; confocal microscopy. These studies place Nramp1 on a membrane in close proximity to obligate intracellular pathogens. A link between Nramp1 and divalent-cation transport is suggested by sequence similarity with yeast SMF1. Evidence showing modulation of Nramp1 protein levels by iron chelation provides a direct link with Nramp1 function and divalent-cation metabolism.

Solute carrier 11a1 (Slc11a1; formerly Nramp1) regulates metabolism and release of iron acquired by phagocytic, but not transferrin-receptor-mediated, iron uptake

2002 ◽  
Vol 363 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Victoriano MULERO ◽  
Susan SEARLE ◽  
Jenefer M. BLACKWELL ◽  
Jeremy H. BROCK
Keyword(s):  
Iron Uptake ◽  
Interferon Γ ◽  
Natural Resistance ◽  
Null Alleles ◽  
Iron Release ◽  
Wild Type ◽  
Bivalent Cation ◽  
Insoluble Form ◽  
Solute Carrier ◽  
Macrophage Protein

Solute carrier 11a1 (Slc11a1; formerly Nramp1; where Nramp stands for natural-resistance-associated macrophage protein) is a proton/bivalent cation antiporter that localizes to late endosomes/lysosomes and controls resistance to pathogens. In the present study the role of Slc11a1 in iron turnover is examined in macrophages transfected with Slc11a1Gly169 (wild-type) or Slc11a1Asp169 (mutant = functional null) alleles. Following direct acquisition of transferrin (Tf)-bound iron via the Tf receptor, iron uptake and release was equivalent in wild-type and mutant macrophages and was not influenced by interferon-γ/lipopolysaccharide activation. Following phagocytosis of [59Fe]Tf—anti-Tf immune complexes, iron uptake was equivalent and up-regulated similarly with activation, but intracellular distribution was markedly different. In wild-type macrophages most iron was in the soluble (60%) rather than insoluble (12%) fraction, with 28% ferritin (Ft)-bound. With activation, the soluble component increased to 82% at the expense of Ft-bound iron (< 5%). In mutant macrophages, 40–50% of iron was in insoluble form, 50–60% was soluble and < 5% was Ft-bound. Western-blot analysis confirmed failure of mutant macrophages to degrade complexes 24h after phagocytic uptake. Confocal microscopy showed that complexes were within lysosome-associated membrane protein 1-positive vesicles in wild-type and mutant macrophages at 30min and 24h, implying failure in the degradative process in mature phagosomes in mutant macrophages. NO-mediated iron release was 2.4-fold higher in activated wild-type macrophages compared with mutant macrophages. Overall, our data suggest that iron acquired by phagocytosis and degradation is retained within the phagosomal compartment in wild-type macrophages, and that NO triggers iron release by direct secretion of phagosomal contents rather than via the cytoplasm.

Selective induction of phospholipase D1 in pathogen-activated human monocytes

2001 ◽  
Vol 358 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Massimo LOCATI ◽  
Elena RIBOLDI ◽  
Raffaella BONECCHI ◽  
Pietro TRANSIDICO ◽  
Sergio BERNASCONI ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Cell Activation ◽  
Interferon Γ ◽  
Culture Conditions ◽  
Enzymic Activity ◽  
Human Monocytes ◽  
Protein Levels ◽  
Phospholipase D1 ◽  
Inducible Protein ◽  
Factor Α

Phospholipase D (PLD) activation is part of the complex signalling cascade induced during phagocyte activation. Two PLD isoforms have been cloned, but their role in phagocyte functions is still poorly defined. We report that resting fresh circulating human monocytes expressed PLD1. PLD1 protein expression was rapidly down-regulated during cell culture. Lipopolysaccharide and pathogen-derived agonists (Candida albicans, arabinoside-terminated lipoarabinomannan and Gram-positive bacteria, but not mannose-capped lipoarabinomannan or double-stranded RNA) strongly induced PLD1 expression at both the mRNA and protein levels. Pro-inflammatory cytokines [interleukin (IL)-1β and tumour necrosis factor α] had only a weak effect, whereas immune cytokines (IL-6 and interferon γ), anti-inflammatory cytokines (IL-13 and IL-10) and chemoattractants (fMet-Leu-Phe and macrophage chemoattractant protein 1) were inactive. None of the agonists tested induced significant changes in the basal expression of PLD2 mRNA. Consistent with PLD1 up-regulation was the observation that PLD enzymic activity was higher in monocytes treated with active-pathogen-derived agonists than in control cells, when stimulated with PMA or with chemotactic agonists (fMet-Leu-Phe and C5a). Thus PLD2 seems to be a constitutive enzyme in circulating monocytes. Conversely, PLD1 is an inducible protein, rapidly regulated during culture conditions and selectively induced during cell activation. Therefore PLD1 might have a relevant role in immune responses against pathogens and in chronic inflammation.

scholarly journals Identification of Keratin 23 as a Hepatitis C Virus-Induced Host Factor in the Human Liver

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 610 ◽  
Author(s):  
Volker Kinast ◽  
Stefan L. Leber ◽  
Richard J. P. Brown ◽  
Gabrielle Vieyres ◽  
Patrick Behrendt ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Liver Disease ◽  
Hepatitis C ◽  
Ectopic Expression ◽  
Host Factor ◽  
Hcv Infection ◽  
Mrna Levels ◽  
Structural Support ◽  
Protein Levels ◽  
Inducible Protein

Keratin proteins form intermediate filaments, which provide structural support for many tissues. Multiple keratin family members are reported to be associated with the progression of liver disease of multiple etiologies. For example, keratin 23 (KRT23) was reported as a stress-inducible protein, whose expression levels correlate with the severity of liver disease. Hepatitis C virus (HCV) is a human pathogen that causes chronic liver diseases including fibrosis, cirrhosis, and hepatocellular carcinoma. However, a link between KRT23 and hepatitis C virus (HCV) infection has not been reported previously. In this study, we investigated KRT23 mRNA levels in datasets from liver biopsies of chronic hepatitis C (CHC) patients and in primary human hepatocytes experimentally infected with HCV, in addition to hepatoma cells. Interestingly, in each of these specimens, we observed an HCV-dependent increase of mRNA levels. Importantly, the KRT23 protein levels in patient plasma decreased upon viral clearance. Ectopic expression of KRT23 enhanced HCV infection; however, CRIPSPR/Cas9-mediated knockout did not show altered replication efficiency. Taken together, our study identifies KRT23 as a novel, virus-induced host-factor for hepatitis C virus.

BRCA1 modulates sensitivity to 5F-203 by regulating xenobiotic stress-inducible protein levels and EROD activity

2007 ◽  
Vol 62 (4) ◽  
pp. 689-697 ◽  
Author(s):  
Hyo Jin Kang ◽  
Hee Jeong Kim ◽  
Sang Hoon Kwon ◽  
Brian DongHoon Kang ◽  
Thomas E. Eling ◽  
...  
Keyword(s):  
Erod Activity ◽  
Xenobiotic Stress ◽  
Protein Levels ◽  
Inducible Protein

scholarly journals Family with sequence similarity 13 member A mediates TGF-β1-induced EMT in small airway epithelium of patients with chronic obstructive pulmonary disease

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jinyuan Zhu ◽  
Faxuan Wang ◽  
Xueyan Feng ◽  
Beibei Li ◽  
Liqiong Ma ◽  
...  
Keyword(s):  
Airway Epithelium ◽  
Smoking Status ◽  
Sequence Similarity ◽  
Small Airway ◽  
Chronic Obstructive ◽  
Tissue Samples ◽  
Protein Levels ◽  
Copd Patients ◽  
Small Airway Epithelium ◽  
Tgf Β1

Abstract Background To explore the role of family with sequence similarity 13 member A (FAM13A) in TGF-β1-induced EMT in the small airway epithelium of patients with chronic obstructive pulmonary disease (COPD). Methods Small airway wall thickness and protein levels of airway remodeling markers, EMT markers, TGF-β1, and FAM13A were measured in lung tissue samples from COPD and non-COPD patients. The correlations of FAM13A expression with COPD severity and EMT marker expression were evaluated. Gain- and loss-of-function assays were performed to explore the functions of FAM13A in cell proliferation, motility, and TGF-β1-induced EMT marker alterations in human bronchial epithelial cell line BEAS-2B. Results Independent of smoking status, lung tissue samples from COPD patients exhibited significantly increased small airway thickness and collagen fiber deposition, along with enhanced protein levels of remodeling markers (collagen I, fibronectin, and MMP-9), mesenchymal markers (α-SMA, vimentin, and N-cadherin), TGF-β1, and FAM13A, compared with those from non-COPD patients. FAM13A expression negatively correlated with FEV1% and PO2 in COPD patients. In small airway epithelium, FAM13A expression negatively correlated with E-cadherin protein levels and positively correlated with vimentin protein levels. In BEAS-2B cells, TGF-β1 dose-dependently upregulated FAM13A protein levels. FAM13A overexpression significantly promoted cell proliferation and motility in BEAS-2B cells, whereas FAM13A silencing showed contrasting results. Furthermore, FAM13A knockdown partially reversed TGF-β1-induced EMT marker protein alterations in BEAS-2B cells. Conclusions FAM13A upregulation is associated with TGF-β1-induced EMT in the small airway epithelium of COPD patients independent of smoking status, serving as a potential therapeutic target for anti-EMT therapy in COPD.

scholarly journals Host interferon-γ inducible protein contributes to Brucella survival

2012 ◽  
Vol 2 ◽  
Author(s):  
Jennifer A. Ritchie ◽  
Adam Rupper ◽  
James A. Cardelli ◽  
Bryan H. Bellaire
Keyword(s):  
Interferon Γ ◽  
Inducible Protein
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