Modulation of voltage-dependent and inward rectifier potassium channels by 15-epi-lipoxin-A4 in activated murine macrophages: implications in innate immunity

J Immunol. 2013 Dec 15;191(12):6136-46. doi: 10.4049/jimmunol.1300235. Epub 2013 Nov 18.

Abstract

Potassium channels modulate macrophage physiology. Blockade of voltage-dependent potassium channels (Kv) by specific antagonists decreases macrophage cytokine production and inhibits proliferation. In the presence of aspirin, acetylated cyclooxygenase-2 loses the activity required to synthesize PGs but maintains the oxygenase activity to produce 15R-HETE from arachidonate. This intermediate product is transformed via 5-LOX into epimeric lipoxins, termed 15-epi-lipoxins (15-epi-lipoxin A4 [e-LXA4]). Kv have been proposed as anti-inflammatory targets. Therefore, we studied the effects of e-LXA4 on signaling and on Kv and inward rectifier potassium channels (Kir) in mice bone marrow-derived macrophages (BMDM). Electrophysiological recordings were performed in these cells by the whole-cell patch-clamp technique. Treatment of BMDM with e-LXA4 inhibited LPS-dependent activation of NF-κB and IκB kinase β activity, protected against LPS activation-dependent apoptosis, and enhanced the accumulation of the Nrf-2 transcription factor. Moreover, treatment of LPS-stimulated BMDM with e-LXA4 resulted in a rapid decrease of Kv currents, compatible with attenuation of the inflammatory response. Long-term treatment of LPS-stimulated BMDM with e-LXA4 significantly reverted LPS effects on Kv and Kir currents. Under these conditions, e-LXA4 decreased the calcium influx versus that observed in LPS-stimulated BMDM. These effects were partially mediated via the lipoxin receptor (ALX), because they were significantly reverted by a selective ALX receptor antagonist. We provide evidence for a new mechanism by which e-LXA4 contributes to inflammation resolution, consisting of the reversion of LPS effects on Kv and Kir currents in macrophages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Calcium / physiology
  • Gene Expression Regulation
  • Immunity, Innate / physiology*
  • Inflammation / genetics
  • Inflammation / metabolism
  • Interleukin-13 / pharmacology
  • Interleukin-4 / pharmacology
  • Ion Transport
  • Kv1.3 Potassium Channel / antagonists & inhibitors
  • Kv1.3 Potassium Channel / biosynthesis*
  • Kv1.3 Potassium Channel / genetics
  • Kv1.5 Potassium Channel / biosynthesis*
  • Kv1.5 Potassium Channel / genetics
  • Lipopolysaccharides / pharmacology
  • Lipoxins / pharmacology*
  • Macrophage Activation / physiology*
  • Mice
  • Mice, Inbred BALB C
  • Nerve Tissue Proteins / biosynthesis
  • Nerve Tissue Proteins / genetics
  • Patch-Clamp Techniques
  • Potassium / physiology
  • Potassium Channel Blockers / pharmacology
  • Potassium Channels, Inwardly Rectifying / biosynthesis*
  • Potassium Channels, Inwardly Rectifying / genetics
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Receptors, Formyl Peptide / agonists
  • Receptors, Formyl Peptide / physiology
  • Scorpion Venoms / pharmacology
  • Specific Pathogen-Free Organisms
  • Up-Regulation

Substances

  • Interleukin-13
  • Kir2.1 channel
  • Kv1.3 Potassium Channel
  • Kv1.5 Potassium Channel
  • Lipopolysaccharides
  • Lipoxins
  • Nerve Tissue Proteins
  • Potassium Channel Blockers
  • Potassium Channels, Inwardly Rectifying
  • RNA, Messenger
  • Receptors, Formyl Peptide
  • Scorpion Venoms
  • formyl peptide receptor 2, mouse
  • lipoxin A4
  • Interleukin-4
  • margatoxin
  • Potassium
  • Calcium