Protective effect of ixerisoside A against UVB-induced pro-inflammatory cytokine production in human keratinocytes

Int J Mol Med. 2015 May;35(5):1411-8. doi: 10.3892/ijmm.2015.2120. Epub 2015 Mar 2.

Abstract

Human skin is the first line of defense for the protection of the internal organs of the body from different stimuli. Ultraviolet B (UVB), one of the harmful radiations for skin, is widely known to induce abnormally increased cytokine release from keratinocytes leading to inflammatory skin disorders. IL-6 and IL-8 induce an acute-phase response and stimulate leukocyte infiltration in the skin. Previous studies have shown that chronic exposure to UVB radiation increases cyclooxygenase-2 (COX‑2) expression through various cell signaling pathways, resulting in skin cancer. Recent studies have shown that the activation of extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 MAPK is strongly correlated with acute inflammation and development of skin cancer caused by an increased expression of COX-2. Ixerisoside A (IXA) is an active constituent of Ixeris dentata of the Compositae (Asteraceae) family. The effect of IXA on skin inflammation has yet to be elucidated. To determine the anti-inflammatory effects of IXA, we examined its effect on UVB-induced pro-inflammatory cytokine production in human keratinocytes (HaCaT cells) by observing these cells in the presence or absence of IXA. In this study, pro-inflammatory cytokine production was determined by enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (rt-pcr), and western blot analysis to evaluate the activation of mitogen-activated protein kinases (MAPKs). IXA inhibited UVB-induced production of the pro-inflammatory cytokines IL-6 and IL-8 in a dose-dependent manner. Moreover, IXA inhibited the expression of COX-2, ERK, JNK, and p38 MAPKs, indicating that the secretion of the pro-inflammatory cytokines IL-6 and IL-8, and COX-2 expression was inhibited by blocking MAPK phosphorylation. These results indicated that IXA potentially protects against UVB-induced skin inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Survival / drug effects
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism
  • Cytokines / biosynthesis*
  • Cytokines / genetics
  • Enzyme Activation / drug effects
  • Gene Expression
  • Humans
  • Inflammation Mediators / metabolism*
  • Keratinocytes / drug effects*
  • Keratinocytes / metabolism*
  • Keratinocytes / radiation effects
  • Lactones / pharmacology*
  • Mitogen-Activated Protein Kinases / metabolism
  • Plant Extracts / pharmacology
  • Protective Agents / pharmacology*
  • Sesquiterpenes / pharmacology*
  • Ultraviolet Rays

Substances

  • Cytokines
  • Inflammation Mediators
  • Lactones
  • Plant Extracts
  • Protective Agents
  • Sesquiterpenes
  • ixerisoside A
  • Cyclooxygenase 2
  • Mitogen-Activated Protein Kinases