Uptake of Malassezia furfur by human dermal fibroblasts: effect of ketoconazole and cytoskeleton inhibitors

We showed the ability of human dermal fibroblasts to take up Malassezia fur fur and the effect of ketoconazole and cytoskeleton inhibitors, including c ytochalasin D and colchicine, on invasivity. Engulfment was evaluated by Ma y Grunwald Giemsa stain and confirmed by acridine orange staining and elect ron microscopy. Both revealed the different steps of engulfment, including a fusion event between lysosomes and phagosomes containing M. furfur. Subin hibitory concentrations of ketoconazole (5 mug/ml) reduced the invasive cap acity compared to controls (52.0 +/- 6.3 vs 10.0 +/- 1.2). M. furfur induce d changes in the cytoskeleton of human dermal fibroblasts, with signs of di saggregation of actin fibres. We also studied the effect of the cytoskeleto n inhibitors, cytochalasin D (I mug/ml) and colchicine (I mug/ml), on engul fment. Cytochalasin D, an inhibitor of actin polymers, inhibited the uptake of M. furfur by human dermal fibroblasts. Colchicine, a microtubule inhibi tor, reduced the uptake of M. furfur less markedly. This suggests that the process of engulfment is F-actin-dependent, but the integrity of microtubul es is also important in "non-professional" phagocytic cells such as dermal fibroblasts.