Introduction of a methoxymethyl side chain into p-phenylenediamine attenuates its sensitizing potency and reduces the risk of allergy induction.

The strong sensitizing potencies of the most important primary intermediates of oxidative hair dyes, p-phenylenediamine (PPD) and p-toluylenediamine (PTD, i.e. 2-methyl-PPD) are well established.

Potential of coculture in vitro models to study inflammatory and sensitizing effects of particles on the lung.

Exposure to particulate matter (PM) like nanoparticles (NPs) has increased in the last century due to increased combustion processes, road traffic, etc. In addition, the progress in chemical and cosmetic industry led to many new compounds, e.g.

Cross talk between keratinocytes and dendritic cells: impact on the prediction of sensitization.

Understanding the mechanistic aspects involved in sensitization by chemicals will help to develop relevant preventive strategies. Many potential sensitizers are not directly immunogenic but require activation outside or inside the skin by nonenzymatic oxidation (prehaptens) or metabolic transformation (prohaptens) prior to being able to induce an immune response. This necessary activation step has not yet been actively integrated into a cell line-based prediction approach.

Impact of aryl hydrocarbon receptor (AhR) knockdown on cell cycle progression in human HaCaT keratinocytes.

Abstract While activation of the aryl hydrocarbon receptor (AhR) by exogenous ligands is well investigated, its physiological function is less understood. By extending research in AhR biology, evidence appeared that the receptor generally plays an important role in cell physiology. In keratinocytes, little is known about endogenous functions of the AhR.

Evaluation of cytochrome P450 1 (CYP1) and N-acetyltransferase 1 (NAT1) activities in HaCaT cells: implications for the development of in vitro techniques for predictive testing of contact sensitizers.

Xenobiotic metabolizing enzymes like cytochrome P450s and N-acetyltransferase are expressed in keratinocytes and professional antigen-presenting cells. Thus, biotransformation of chemicals applied to the skin can be relevant for their potential to cause skin toxicity and immune responses like allergic contact dermatitis. Considering the keratinocyte cell line HaCaT as a relevant in vitro tool for epidermal biotransformation, we specifically investigated CYP1 (EROD) and N-acetyltransferase 1 (NAT1) activities of three different HaCaT shipments and human primary keratinocytes (NHEK).