Ulrike Gabriele Larsen

The cellular distribution of extracellular superoxide dismutase in macrophages is altered by cellular activation but unaffected by the natural occurring R213G substitution

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  • Randi Heidemann Gottfredsen, Denmark
  • David Goldstrohm, National Jewish Health, United States
  • John Hartney, National Jewish Health, United States
  • Ulrike Gabriele Larsen
  • Russel Bowler, National Jewish Health, United States
  • Steen Vang Petersen
Extracellular superoxide dismutase (EC-SOD) is responsible for the dismutation of the superoxide radical produced in the extracellular space and known to be expressed by inflammatory cells, including macrophages and neutrophils. Here we show that EC-SOD is produced by resting macrophages and associated with the cell surface via the extracellular matrix (ECM)-binding region. Upon cellular activation induced by lipopolysaccharide, EC-SOD is relocated and detected both in the cell culture medium and in lipid raft structures. Although the secreted material presented a significantly reduced ligand-binding capacity, this could not be correlated to proteolytic removal of the ECM-binding region, because the integrity of the material recovered from the medium was comparable to that of the cell surface-associated protein. The naturally occurring R213G amino acid substitution located in the ECM-binding region of EC-SOD is known to affect the binding characteristics of the protein. However, the analysis of macrophages expressing R213G EC-SOD did not present evidence of an altered cellular distribution. Our results suggest that EC-SOD plays a dynamic role in the inflammatory response mounted by activated macrophages.
Original languageEnglish
JournalFree Radical Biology & Medicine
Pages (from-to)348-356
Number of pages9
Publication statusPublished - 2014

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