Role of TNF-α and extracellular ATP in THP-1 cell activation following allergen exposure

Abstract

-Dendritic cells (DCs), including Langerhans cells (LCs), play a critical role in the induction phase of allergic contact hypersensitivity. Following exposure to chemical allergens in the skin, LCs undergo a maturation process leading to the up-regulation of expression of co-stimulatory molecules, such as CD86, CD54 and CD40. Our previous study revealed that chemical allergens induce phenotype alterations (e.g., CD86, CD54 and CD40) and cytokine production (TNF-α and IL-8) in THP-1 cells that possibly reflect the maturation of dendritic cells during skin sensitization. However, the physiological signals for phenotypic alterations by chemical allergens are still not fully understood. Therefore, in this study, we investigated the effect of TNF-α and extracellular ATP on THP-1 cell activation induced by chemical allergens. Kinetic studies revealed that TNF-α and IL-8 release occurred in a time-dependent manner with release of two cytokines beginning at 3 hr post-exposure to well-known haptens, DNCB and NiSO 4 . While recombinant human TNF-α augmented CD54 and CD40 expression in a dose-dependent manner, rhTNF-α did not increase CD86 expression. Furthermore, neutralization of TNF-α activity strongly inhibited CD54 and CD40 expression induced by allergens. On the contrary, extracellular ATP induced the up-regulation of both CD86 and CD54 expression. In the presence of the P2 receptor antagonist suramin, the up-regulation of CD86 and CD54 expression by allergens was in part suppressed. Therefore, we postulate that not only TNF-α but also extracellular ATP may contribute to cell activation following allergen stimulation, which might reflect the mechanism by which DCs respond to allergens.

Identification of PDL-1 as a novel biomarker of sensitizer exposure in dendritic-like cells

“…RANTES has been previously identified in vivo as being a key cytokine in the murine ear test to DNCB (Baumer et al, 2004) thus supporting its relevance as an in vitro biomarker. In order to compare the sensitizer predictability of RANTES with a currently used cytokine (Mitjans et al, 2008, Toebak et al, 2006, Miyazawa et al, 2008 we investigated the generation of IL-8 on MUTZ-3 cells. Our unpublished data showed that IL-8 was increased comparably to the sensitizers seen for RANTES, thus, RANTES can be considered as extending the in vitro biomarkers available for sensitizer testing.…”

“…Researchers have identified a number of cytokines of importance in the sensitization process which may constitute an important aspect of in vitro test development. Recent studies suggested that IL-8 detection following sensitizer or nonsensitizer application to THP-1 cells could function as a promising in vitro model to assist with sensitization screening (Mitjans et al, 2008, Miyazawa et al, 2008, Toebak et al, 2006.…”

The relationship between CD86 and CD54 protein expression and cytotoxicity following stimulation with contact allergen in THP-1 cells

“…These results suggest that augmentation of protein expression due to contact allergen exposure does not depend on humoral factors from dead caused by allergen exposure. Miyazawa et al (2008b) reported that the TNF-α from THP-1 cells activated by contact allergens was related to CD86 and CD54 expression. But in contrast, there is no induction of CD86 and CD54 expression after incubation with humoral factors from dead cells.…”

“…Also, it has been reported that expression of CD86 and the production of IL-1β and IL-8 are induced in U937 cells when exposed to sensitizers, such as 2,4,6-Trinitrobenzene sulfonic acid (TNBS), DNCB, Eugenol (EU), Citral and so on (Python et al, 2007). In addition, cell signaling events inducing such phenotypic alterations were investigated using THP-1 cell line (Miyazawa et al, 2008a(Miyazawa et al, , 2008b. These phenotypic alterations are expected to be the indicators for the identification of contact sensitizers.…”

The Adverse Outcome Pathway for Skin Sensitisation Initiated by Covalent Binding to Proteins

“…p38 MAPK, ERK, PGK, and NFκB) (Trompezinski et al, 2008;dos Santos et al, 2009). co-workers (2008a and2008b) examined P38 MAPK, a mitogen-activated protein kinase, and ERK, an extracellular signal-regulated kinase in THP-1 cells. It is important to note that moderate and weak sensitizers needed 10x and 100x higher exposure concentrations, respectively, than strong sensitizers to activate kinase pathways.…”