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Lindmark, Maria
Publications (2 of 2) Show all publications
Cedergren, J., Follin, P., Forslund, T., Lindmark, M., Sundqvist, T. & Skogh, T. (2003). Inducible nitric oxide synthase (NOS II) is constitutive in human neutrophils. APMIS, 111(10), 963-968
Open this publication in new window or tab >>Inducible nitric oxide synthase (NOS II) is constitutive in human neutrophils
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2003 (English)In: APMIS, ISSN 0903-4641, Vol. 111, no 10, p. 963-968Article in journal (Refereed) Published
Abstract [en]

The objective was to study the expression of inducible nitric oxide synthase (NOS II) in and NO production by human blood neutrophils and in in vivo exudated neutrophils. Cellular expression of NOS II was evaluated by flow cytometry in whole blood, in isolated blood neutrophils, and in neutrophils obtained by exudation in vivo into skin chambers. Neutrophil NOS II was also demonstrated by Western blotting. Uptake of 3H-labelled L-arginine was studied in vitro and NOS activity measured in a whole cell assay by the conversion of 3H-arginine to 3H-citrulline. In contrast to unseparated blood cells, NOS II was demonstrable both in isolated blood neutrophils and exudated cells. The failure to detect NOS II by flow cytometry in whole blood cells thus proved to be due to the quenching effect of hemoglobin. Western blotting revealed a 130 kD band corresponding to NOS II in isolated blood neutrophils, but detection was dependent on diisopropylfluorophosphate for proteinase inhibition. L-arginine was taken up by neutrophils, but enzymatic activity could not be demonstrated. We conclude that human neutrophils constitutively express NOS II, but that its demonstration by FITC-labelling is inhibited by hemoglobin-mediated quenching in whole blood samples.

Keywords
Inflammation, nitric oxide, iNOS, granulocytes
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14587 (URN)10.1034/j.1600-0463.2003.1111008.x (DOI)
Available from: 2007-08-27 Created: 2007-08-27 Last updated: 2015-08-31
Lindmark, M. (2003). Regulation of phagocytosis and phagolysosome fusion in human leukocytes. (Doctoral dissertation). Linköping: Linköpings universitet
Open this publication in new window or tab >>Regulation of phagocytosis and phagolysosome fusion in human leukocytes
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Professional phagocytes such as neutrophil granulocytes and macrophages are an esential part of the innate immune system. The neutrophils form the first line of defence against invading microorganisms and are important for rapid killing of the intruders. Macrophages arrive later at the site of infection, kill micoorganisms, degrade dead cells, present antigens and secrete substances that orchestrate the inflammatory response. Neutrophils and macrophages ingest and kill microorganisms in a process called phagocytosis, where calcium signalling has shown to be involved. Inside the cell the microorganism is enclosed in a phagosome, that sequentially fuses with various intracellular vesicles to form a phagolysosome in which the intruder is killed. Killing is achieved through the actions of lytic enzymes, nitrogen oxide (NO) and reactive oxygen metabolites (ROM). Studies on the regulation of phagocytosis are essential since many pathogens are able to survive by interfering with this process. In the first study we investigated intracellular signalling in human neutrophils following engagement of a phagocytic receptor, complement receptor 3 (CR3). For this, we used antibody-coated PANSORBINS® which bound to the ß-chain of CR3 without inducing phagocytosis. We found that these particles elicited an intracellular production of ROM which was dependent on the cytoskeleton and on phospholipase D. In the second study, we showed that the putative calcium-sensor synaptotagmin II is present in neutrophils and is involved in phagocytosis. Synaptotagmin II was found on the specific granules and translocated to the phagosome in a calcium-dependent manner during eR-mediated phagocytosis and to the plasma membrane after stimulation with the formylated peptide, N-formyl-methionyl-leucyl-phenylalanine. In the third study, we demonstrate the presence of synaptotagmin IV in human macrophages. Synaptotagmin IV translocated transiendy to macrophage phagosomes during eR- and FcγR-mediated phagocytosis. We also found that eR- and FcyR-mediated uptake was calcium dependent in these cells. In the fourth study, we show that lipophosphoglycan (LPG) from Leishmania donovani induced elevated levels of periphagosomal F-actin, inhibition of phagolysosome maturation and diminished production of ROM in neutrophils during eR-mediated phagocytosis. Together, our data show that generation of ROM occurs early during eR-mediated phagocytosis and could be involved in intracellular signalling, that synaptotagmins are present in professional phagocytes and could act as calcium sensors in phagosomal maturation and secretion, and that LPG can be used as a tool to investigate how actin can regulate phagosomal maturation in neutrophils.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2003. p. 64
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 818
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-26661 (URN)11227 (Local ID)91-7373-509-4 (ISBN)11227 (Archive number)11227 (OAI)
Public defence
2003-11-06, Aulan, Hälsans Hus, Universitetet, Linköping, 09:00 (Swedish)
Opponent
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-10-17Bibliographically approved
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