Influence of the polyunsaturated fatty acids linoleic acid, arachidonic acid, [alpha]-linolenic acid and [gamma]-linolenic acid on melanogenesis of B16 mouse melanoma cells and normal human melanocytes

Abstract

The influence of the polyunsaturated fatty acids (PUFA) linoleic acid, arachidonic acid, α-linolenic acid and γ-linolenic acid on pigmentation was examined using different in vitro models: monolayer cultures of B16 mouse melanoma cells, monolayer cultures of normal human melanocytes and a commercially available reconstructed pigmented epidermis that consists of normal, human-derived epidermal keratinocytes (NHEK) and melanocytes (NHM) which have been cul tured to form a multilayered, highly differentiated model of the human epidermis that exhibits in vivo - l ike morphological and ultrastructural characteristics. We used two different sublines of B16 origin called B16-F1 and B16-F10 for our experiments. In both sublines 25 μM of the PUFA listed above showed two distinct effects on melanogenesis of the cells: 1) the secretion of intracellularly produced melanin into the extracellular culture fluid was enhanced, and 2) the intracellular melanin content was decreased. The stimulation of melanin secretion was highest after an incubation time of 24 h, whereas the reduction of intracellular melanin was most effective after 72 h. α-Linolenic acid and γ-linolenic acid decreased intracellular melanin content more effectively than arachidonic acid and linoleic acid. Futhermore intracellular melanin content of murine melanoma cells was reduced more effectively in B16-F10 subline. In both sublines tyrosinase activity was not affected, whereas tyrosinase content was reduced. Tyrosinase mRNA level of B16-F1 cells was decreased by linoleic and arachidonic acid. None of the fatty acids had an influence on tyrosinase mRNA levels of B16-F10 cel l s . None of the polyunsaturated fatty acids at a concentration of 100 μM affected the melanogenesis of monolayer cul tures of NHM when measuring the changes in mRNA level, content and activity of tyrosinase and in the amount of intracellular pigment. In addition the polyunsaturated fatty acids did not inhibit the pigmentation of the reconstructed pigmented epidermis.