A heteroglycan from the cyanobacterium Nostoc commune modulates LPS-induced inflammatory cytokine secretion by THP-1 monocytes through phosphorylation of ERK1/2 and Akt

Astridur Olafsdottir, Gudny Ella Thorlacius, Sesselja Omarsdottir, Elin Soffia Olafsdottir, Arnor Vikingsson, Jona Freysdottir, Ingibjorg Hardardottir*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Cyanobacteria (blue-green algae) have been consumed as food and used in folk medicine since ancient times to alleviate a variety of diseases. Cyanobacteria of the genus Nostoc have been shown to produce complex exopolysaccharides with antioxidant and antiviral activity. Furthermore, Nostoc sp. are common in cyanolichen symbiosis and lichen polysaccharides are known to have immunomodulating effects. Nc-5-s is a heteroglycan isolated from free-living colonies of Nostoc commune and its structure has been characterized in detail. The aim of this study was to determine the effects of Nc-5-s on the inflammatory response of lipopolysaccharide (LPS)-stimulated human THP-1 monocytes and how the effects are mediated. THP-1 monocytes primed with interferon-γ and stimulated with LPS in the presence of Nc-5-s secreted less of the pro-inflammatory cytokine interleukin (IL)-6 and more of the anti-inflammatory cytokine IL-10 than THP-1 monocytes stimulated without Nc-5-s. In contrast, Nc-5-s increased LPS-induced secretion of the pro-inflammatory cytokines tumor necrosis factor (TNF)-α and IL-8. Nc-5-s decreased LPS-induced phosphorylation of the extracellular regulated kinase (ERK)1/2 and Akt kinase, but did not affect phosphorylation of the p38 kinase, activation of the nuclear factor kappa B pathway, nor DNA binding of c-fos. These results show that Nc-5-s has anti-inflammatory effects on IL-6 and IL-10 secretion by THP-1 monocytes, but its effects are pro-inflammatory when it comes to TNF-α and IL-8. Furthermore, they show that the effects of Nc-5-s may be mediated through the ERK1/2 pathway and/or the Akt/phosphoinositide 3-kinase pathway and their downstream effectors. The ability of Nc-5-s to decrease IL-6 secretion, increase IL-10 secretion and moderate ERK1/2 activation indicates a potential for its development as an anti-inflammatory agent.

Original languageEnglish
Pages (from-to)1451-1457
Number of pages7
JournalPhytomedicine
Volume21
Issue number11
DOIs
Publication statusPublished - 25 Sept 2014

Bibliographical note

Funding Information:
This work was supported by the Icelandic Research Fund ( 110418023 ), the Icelandic Research Fund for Graduate Students ( R10-0008 ), the University of Iceland Research Fund , the Landspitali University Hospital Research Fund and the Bergthora Magnusdóttir and Jakob Bjarnason Memorial Fund . We thank Dr. Hordur Kristinsson, lichenologist, for providing the image of N. commune used in the graphical abstract.

Other keywords

  • IL-10 ERK1/2
  • IL-6
  • Nostoc commune
  • Polysaccharides
  • THP-1 cells

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