Pigment transfer in mammalian epidermis

Sn, Klaus

doi:10.1001/archderm.100.6.756

Cited by 24 publications

(18 citation statements)

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“…Melanosome-containing vesicles are discharged from a melanocyte into extracellular spaces, and subsequently engulfed by neighboring keratinocytes. Our findings are consistent with one of the three prevailing models proposed by in vitro studies6789101112131415161718192021 (See also Introduction). Of course, our study does not exclude the other models of cytophagocytosis- and exocytosis-mediated transfer67810111521, and it is indeed underway to see if melanocytes in different locations of the body send their melanosomes in a different way.…”

Section: Discussionsupporting

confidence: 91%

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Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by vesicle release associated with Rho-regulated membrane blebbing

Tadokoro

Murai

Sakai

et al. 2016

Sci Rep

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During skin pigmentation in amniotes, melanin synthesized in the melanocyte is transferred to keratinocytes by a particle called the melanosome. Previous studies, mostly using dissociated cultured cells, have proposed several different models that explain how the melanosome transfer is achieved. Here, using a technique that labels the plasma membrane of melanocytes within a three-dimensional system that mimics natural tissues, we have visualized the plasma membrane of melanocytes with EGFP in chicken embryonic skin. Confocal time-lapse microscopy reveals that the melanosome transfer is mediated, at least in part, by vesicles produced by plasma membrane. Unexpectedly, the vesicle release is accompanied by the membrane blebbing of melanocytes. Blebs that have encapsulated a melanosome are pinched off to become vesicles, and these melanosome-containing vesicles are finally engulfed by neighboring keratinocytes. For both the membrane blebbing and vesicle release, Rho small GTPase is essential. We further show that the membrane vesicle-mediated melanosome transfer plays a significant role in the skin pigmentation. Given that the skin pigmentation in inter-feather spaces in chickens is similar to that in inter-hair spaces of humans, our findings should have important consequences in cosmetic medicine.

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Section: Discussionsupporting

confidence: 91%

“…Studies using these techniques have proposed three prominent models to explain how the melanosome transfer is achieved6789101112131415161718192021. First model is that the melanosome-containing tip of a dendrite or filopodium protruding from melanocytes is directly cytophagocytosed by adjacent keratinocytes.…”

mentioning

confidence: 99%

Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by vesicle release associated with Rho-regulated membrane blebbing

Tadokoro

Murai

Sakai

et al. 2016

Sci Rep

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“…Two possible pathways for transferring melanin pigment outside the cytosol of melanocytes have been proposed: first, a phagocytic process during which the keratinocytes engulf the tip of the dendritic process of melanocytes including melanosomes (Klaus 1969;Wolff 1973). Second is a process where melanosomal membranes fuse to the cellular membranes and excrete the melanin pigment outside the melanocytes followed by uptake by keratinocytes (Moellmann et al 1988;Yamamoto and Bhawan 1994;Virador et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Evidence that the small GTPase Rab8 is involved in melanosome traffic and dendrite extension in B16 melanoma cells

Chakraborty

Funasaka

Araki

et al. 2003

Cell and Tissue Research

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One of the major activities of melanocytes in skin is to produce melanin and transport it via dendrites to neighboring keratinocytes. Here, we present evidence that Rab8, a member of the small GTPase superfamily, is present in purified melanosomal fractions, and is upregulated by pigmentogenic agents like melanocyte-stimulating hormone/isobutylmethyl xanthine (MSH/IBMX) and ultraviolet radiation B (UVB). Confocal immunofluorescence microscopic studies revealed that Rab8 is colocalized with Mel5, a melanosomal protein, at the trans-Golgi area and in the cytoplasmic vesicles of B16 cells. During MSH/IBMX treatment, while a number of dendrites with numerous processes are formed, colocalization is extended towards the tips of protrusions. Since process formation is supported by cytoskeletal assembly as well as membrane transport, we tested the colocalization of Rab8 with actin filaments in B16 cells. Rab8, indeed, colocalized with phalloidin, mostly at the periphery, but when irradiated with UVB, cells were rounded instead of dendritic, and colocalization was found predominantly at the cytoplasmic area. Further, suppression of Rab8 expression by its antisense oligonucleotide revealed the reduction in staining intensity of Rab8 but not of Mel5, dendrite formation and melanosome transport towards the tips of the dendrites in B16 melanoma cells. Taken together, it is suggestive that Rab8, in B16 melanoma cells, might have a role in melanosome traffic and dendrite extension, both in constitutive and regulated fashion.

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“…Melanins are synthesized in tyrosinase-containing melanosomes within the melanocyte. The melanosomes are transferred to keratinocytes through the tips of dendrites of the melanocyte (Mottaz and Zelickson, 1967;Klaus, 1969;Jimbow et al, 1976;Marks and Seabra, 2001). The examination of tissue specimens has revealed that the highest density of melanin, forming melanosome clusters is present in the epidermal basal layer (Gates and Zimmermann, 1953;Szabo, 1969;Montagna and Carlisle, 1991;Byers et al, 2003).…”

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confidence: 99%

Non-Invasive Visualization of Melanin and Melanocytes by Reflectance-Mode Confocal Microscopy

Yamashita

Kuwahara

González

et al. 2005

Journal of Investigative Dermatology

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In vivo visualization of epidermal melanin was performed by reflectance-mode confocal microscopy (RCM). Firstly, we examined the distribution of epidermal melanin in pigmented animals and compared with that of the human skin. Melanocytes in the skin of pigmented animals were found to accumulate a large amount of melanin that can be easily visualized because of its brightness. Their RCM images correlated well with the Fontana-Masson-stained sections for melanin. In contrast, in the human skin, typical dendritic melanocytes were hardly observed even in pigmented lesions, although supranuclear melanin caps were easily visible. These results suggested that human melanocytes rapidly transfer the produced melanin to keratinocytes and do not accumulate it. Secondly, to elucidate the production of melanin by human melanocytes, we evaluated the changes of melanin after a single ultraviolet (UV) exposure. The melanin-accumulating melanocytes were clearly visualized during the skin pigmentation process. The RCM images showed the brightness because of melanin gradually increased from day 4, then dendrite-elongated melanocytes appearing from day 8, and finally melanin caps formed from day 29. In conclusion, RCM successfully evidenced the difference in melanin distribution between the pigmented animals and humans, and the UV-induced pigmentation process in vivo as well.

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Pigment transfer in mammalian epidermis

Cited by 24 publications

References 0 publications

Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by vesicle release associated with Rho-regulated membrane blebbing

Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by vesicle release associated with Rho-regulated membrane blebbing

Evidence that the small GTPase Rab8 is involved in melanosome traffic and dendrite extension in B16 melanoma cells

Non-Invasive Visualization of Melanin and Melanocytes by Reflectance-Mode Confocal Microscopy

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