House Dust Mite Allergen Der f 2-induced Phospholipase D1 Activation Is Critical for the Production of Interleukin-13 through Activating Transcription Factor-2 Activation in Human Bronchial Epithelial Cells

Abstract

The purpose of this study was to identify the role of phospholipase D1 (PLD1) in Der f 2-induced interleukin (IL)-13 production. The major house dust mite allergen, Der f 2, increased PLD activity in human bronchial epithelial cells (BEAS-2B), and dominant negative PLD1 or PLD1 siRNA decreased Der f 2-induced IL-13 expression and production. Treatment of Der f 2 activated the phospholipase C␥ (PLC␥)/protein kinase C␣ (PKC␣)/p38 MAPK pathway. Der f 2-induced PLD activation was attenuated by PLC␥ inhibitors (U73122 and PAO), PKC␣ inhibitors (RO320432 and GO6976), and p38 MAPK inhibitors (SB203580 and SB202190). These results indicate that PLC␥, PKC␣, and p38 MAPK act as upstream activators of PLD in Der f 2-treated BEAS-2B cells. Furthermore, expression and production of IL-13 increased by Der f 2 were also blocked by inhibition of PLC␥, PKC␣, or p38 MAPK, indicating that IL-13 expression and production are related to a PLC␥/PKC␣/p38 MAPK pathway. We found that activating transcription factor-2 (ATF-2) was activated by Der f 2 in BEAS-2B cells and activation of ATF-2 was controlled by PLD1. When ATF-2 activity was blocked with ATF-2 siRNA, Der f 2-induced IL-13 expression and production were decreased. Thus, ATF-2 might be one of the transcriptional factors for the expression of IL-13 in Der f 2-treated BEAS-2B cells. Taken together, PLD1 acts as an important regulator in Der f 2-induced expression and production of IL-13 through activation of ATF-2 in BEAS-2B cells.

Cigarette smoke extract-induced interleukin-6 expression is regulated by phospholipase D1 in human bronchial epithelial cells

“…Overexpression of catalytically inactive mutants of PLD attenuates LPA-induced IL-13Ralpha2 gene expression and protein secretion (Zhao et al, 2007). House dust mite allergen Derf2-induced PLD1 activation is critical for IL-13 production (Park et al, 2009). However, the involvement of PLD in CSE-induced inflammation responses has not been well described.…”

“…Our previous reports have shown that PLD is regulated via PLC in rat alveolar macrophages (Cha et al, 1998), via PKC in peripheral blood mononuclear cells (Oh et al, 2000) and T cells from Dermatophagoides farinae-allergic individuals (Oh et al, 2004) and via a PLC/PKC/p38MAPK pathway in BEAS-2B cells (Park et al, 2009). To further elucidate the relevance of a PLC/ PKC/p38MAPK pathway in CSE-induced PLD1 and IL-6 expressions, BEAS-2B cells were pretreated with PAO (PLC inhibitor), Go6976 (PKC inhibitor), and SB203580 (p38MAPK inhibitor) for 30 min prior to being treated with CSE for 1 hr and harvested.…”

“…To examine the possible correlation between PLD1 and IL-6 expression, we hypothesized, based on reports that PLD mediates IL-8 expression and IL-13 production (Park et al, 2009) in BEAS-2B cells, that PLD1 could regulate IL-6 expression at an upstream level. To determine whether PLD could regulate IL-6 expression and, if so, which isozymes of PLD could be involved, BEAS-2B cells were transfected with wild type and catalytically inactive dominant negative (DN) mutant forms of PLD1 and PLD2.…”

“…Transcription factors ATF2 and STAT3 are well-known regulators of cytokine expression (Riebe et al, 2011;Park et al, 2009;Zhang et al, 2015). To investigate the role of PLD1 in IL-6 expression induced by CSE, we examined the effects of PLD1 siRNA transfection.…”

“…Several reports indicate that IL-6 production and secretion increase when cells are exposed to certain conditions, such as exposure to environmental allergens, infectious stimuli, and cigarette smoke, which can result in lung inflammation, atopy, asthma (Singh et al, 2009), rheumatoid arthritis (Wei et al, 2012;Yoshida and Tanaka, 2014), lung cancer (Chen et al, 2012;Yao et al, 2014), and emphysema (Xiong et al, 2011). In addition, IL-6 production is reported to be mediated in PKC (Hao et al, 2010), MAPK (Wei et al, 2012;Schaper and Rose-John, 2015), p38MAPK (Riebe et al, 2011), JNK (Zhao et al, 2007;Al-Sadi et al, 2014;Chuang et al, 2014), NFkappaB (Chen et al, 2012;Wang et al, 2015), STAT3 (Riebe et al, 2011) and ATF2 (Park et al, 2009) dependent manners. The above study results suggest there may be a relationship between PLD and CSE-induced IL-6 expression.…”