Nonylphenol Induces Cytoskeletal Changes And Release Of Proinflammatory Mediators In Rat Sertoli Cells In Vitro

Abstract

Nonylphenol (NP), an alkylphenol present in plasticizers, is an endocrine disrupting chemical that is potentially dangerous for male reproduction in mammals including man. Because Sertoli cells (SC) provide structural and metabolic support to germ cells, in this study the hypothesis that exposures of SC to NP affect their metabolic functions and the production of bioactive molecules was evaluated. Primary cultures of SC were preincubated with [3 H]arachidonic acid (AA) to label their lipids and then were treated with NP. The NP exposures resulted in increased concentrations of free AA in cells and medium, indicating that such AA was released from [3 H]-labeled lipids (p<0.01). This lipid was mostly phosphatidylinositol, acted upon after activation of a protein kinase A (PKA)/cytoplasmic phospholipase A2 (cPLA2). In NP-exposed SC, an increase of diacylglycerols (DAG) also took place in both, cells and medium (p<0.01). Part of such DAG may have served as second messengers, since NP-increased DAG were associated with an augmented production of PGE2 and expression (mRNA) of COX2. Since the network of vimentin intermediate filaments is important for intracellular lipid transport, the effects of NP on the structure of this network in relation to the formation of cytoplasmic lipid droplets (LD) was studied. In NP-treated SC, the vimentin network was redistributed and the LD size was increased. The NP-dependent cytoskeletal redistribution was prevented by preincubation with H89, a PKA inhibitor. The formation of large LD was prevented by preincubation with either H89 or MEP, a PLA2 inhibitor, suggesting the participation of PKA and cPLA2 in LD biogenesis. We conclude that NP is involved in activating the proinflammatory pathway in SC, by providing the AA that is necessary for prostaglandin synthesis via PKA/PLA2 on the one hand, and by generating the DAG that is required as cofactor of the PKC-mediated activation of the NF- κβ/Cox-2 inflammatory pathway on the other.