Engineered Nanomaterials at Physiologically Relevant Doses Promote Keratinocyte Migration via Induction of Autophagy- and Redox-Dependent Pathways

The proliferating incorporation of engineered nanomaterials (ENMs) in everyday consumer products, such as sunscreen, poses concerns about the dermal exposure effects of these ENMs. Well-characterized ENMs, titanium dioxide and zinc oxide, are utilized as models to understand ENM interactions with skin cells and their influence on wound closure. The ENMs, at relevant exposure doses, have been demonstrated to promote the wound closure process in both in vitro and ex vivo skin explant models. Mechanistic studies reveal that the wound closure process is modulated by intracellular ROS production, with the involvement of autophagy, JNK, and ERK signaling pathways, to promote ENM-induced focal adhesion turnover, microtubule remodeling, and cell migration.