Prostaglandin I-2 Suppresses Proinflammatory Chemokine Expression, CD4 T Cell Activation, and STAT6-Independent Allergic Lung Inflammation
JOURNAL OF IMMUNOLOGY
Authors: Zhou, Weisong; Zhang, Jian; Goleniewska, Kasia; Dulek, Daniel E.; Toki, Shinji; Newcomb, Dawn C.; Cephus, Jacqueline Y.; Collins, Robert D.; Wu, Pingsheng; Boothby, Mark R.; Peebles, R. Stokes, Jr.
Allergic airway diseases are immune disorders associated with heightened type 2 immune responses and IL-5 and IL-13 production at the site of inflammation. We have previously reported that cyclooxygenase (COX) inhibition by indomethacin augmented allergic airway inflammation in a STAT6-independent manner. However, the key COX product(s) responsible for restraining indomethacin-mediated STAT6-independent allergic inflammation is unknown. In this study, using the mouse model of OVA-induced allergic airway inflammation, we identified that PGI(2) receptor (IP) signaling was critical for indomethacin-induced, STAT6-independent proallergic effects. We demonstrated that IP deficiency increased inflammatory cell infiltration, eosinophilia, and IL-5 and IL-13 expression in the lung in a STAT6-independent manner. The augmented STAT6-independent allergic inflammation correlated with enhanced primary immune responses to allergic sensitization and elevated production of multiple inflammatory chemokines (CCL11, CCL17, CCL22, and CXCL12) in the lung after allergen challenge. We also showed that the PGI(2) analogue cicaprost inhibited CD4 T cell proliferation and IL-5 and IL-13 expression in vitro, and IP deficiency diminished the stimulatory effect of indomethacin on STAT6-independent IL-5 and IL-13 responses in vivo. The inhibitory effects of PGI(2) and the IP signaling pathway on CD4 T cell activation, inflammatory chemokine production, and allergic sensitization and airway inflammation suggest that PGI(2) and its analogue iloprost, both Food and Drug Administration-approved drugs, may be useful in treating allergic diseases and asthma. In addition, inhibiting PGI(2) signaling by drugs that either block PGI(2) production or restrain IP signaling may augment STAT6-independent pathways of allergic inflammation.
Effect of isosecotanapartholide isolated from Artemisia princeps Pampanini on IL-33 production and STAT-1 activation in HaCaT keratinocytes
MOLECULAR MEDICINE REPORTS
Authors: Oh, Chang Taek; Jang, Yu-Jin; Kwon, Tae-Rin; Im, Songi; Kim, Soon Re; Seok, Joon; Kim, Gun-Yong; Kim, Young-Heui; Mun, Seog Kyun; Kim, Beom Joon
The present study aimed to investigate the anti-inflammatory effect and mechanism of action of isosecotanapartholide (ISTP), isolated from Artemisia princeps Pampanini extract (APE). The effects of ISTP and APE on the proliferation of human keratinocytes following stimulation by tumor necrosis factor-alpha/interferon-gamma were assessed. ISTP and APE downregulated the expression levels of signal transducer and activator of transcription-1 (STAT-1), and reduced interleukin-33 (IL-33) production. ISTP and APE inhibited the mRNA expression levels of thymus and activation-regulated chemokine (TARC/CCL17) in a dose-dependent manner. Western blot analysis demonstrated that ISTP and APE dose-dependently inhibited protein expression levels of intercellular adhesion molecule-1 and phosphorylation of STAT-1. The results of the present study indicate that ISTP may inhibit TARC/CCL17 production in human epidermal keratinocytes via the STAT-1 signaling pathway and may be associated with the inhibition of IL-33 production. The current study indicated that ISTP is an active component in APE and may be a potential therapeutic agent for the treatment of inflammatory skin disorders.