Di-n-butyl phthalate modifies PMA-induced macrophage differentiation of THP-1 monocytes via PPARγ

• Published in: Toxicology in vitro 2019-02, Vol.54, p.168-177
• Main Authors: Grytting, Vegard Sæter, Olderbø, Bergitte Pearl, Holme, Jørn A., Samuelsen, Jan Tore, Solhaug, Anita, Becher, Rune, Bølling, Anette Kocbach
• Format: Article
• Language: English
• Subjects: 12-O-Tetradecanoylphorbol-13-acetate; Acetic acid; Antagonists; Asthma; Binding sites; CD36; CD36 antigen; CD36 Antigens - metabolism; Cell Differentiation - drug effects; di-n-butyl phthalate; Dibutyl Phthalate - pharmacology; Differentiation; Flow cytometry; Humans; Ligands; Macrophage; Macrophages; Macrophages - cytology; Macrophages - drug effects; Macrophages - metabolism; Monocytes; Monocytes - cytology; Monocytes - drug effects; Monocytes - metabolism; n-Butyl phthalate; Phthalate; PPAR gamma - agonists; PPAR gamma - antagonists & inhibitors; PPAR gamma - metabolism; PPARγ; Proteins; Proteomics; Rosiglitazone; Surface markers; Tetradecanoylphorbol Acetate; THP-1 Cells; Toxicology
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2018.09.004

The present study examined the effects of di-n-butyl phthalate (DBP) on phorbol myristate acetate (PMA)-induced macrophage differentiation of THP-1 monocytes, determined by morphological classification and flow cytometry. Focusing on the expression of the surface marker CD36, the potential role of peroxisome proliferator-activated receptor gamma (PPARγ) was examined using various PPARγ agonists and antagonists. As the PPARγ ligand-binding domain contains multiple ligand-binding sites (LBS), agonist and antagonists targeting the different sites were used. DBP accelerated PMA-induced morphological changes and increased expression of CD36, although to a lesser degree than the PPARγ agonists rosiglitazone and 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2). A proteomics screening revealed that DBP enhanced the expression of PPARγ-regulated proteins. During combined exposures, DBP partly attenuated the effect of rosiglitazone, an agonist binding reversibly to PPARγ's canonical LBS. In contrast, DBP increased expression of CD36 in combination with 15d-PGJ2 which binds irreversibly to the canonical LBS. Thus, DBP appears to interact with both the canonical and alternative LBS. Accordingly, the antagonist GW9662, which binds to the canonical LBS, only partly reduced the DBP-induced CD36 expression, while the dual-site antagonist SR16832 completely blocked the effects of DBP. Overall, the results show that DBP modifies PMA-induced differentiation of THP-1 cells through interaction with PPARγ. •DBP modified the PMA-induced morphology of THP-1 cells•DBP enhanced the PMA-induced expression of the surface marker CD36•Proteomics screening suggested that these effects were mediated via PPARγ.•Experiments with PPARγ agonists and antagonists confirmed a role for PPARγ in DBP-induced CD36 expression.•DBP binding seemed to occur at both the canonical and alternative ligand-binding site.