Mechanisms of skin tanning in different racial/ethnic groups in response to ultraviolet radiation.
Ultraviolet radiation stimulates pigmentation in human skin, but the mechanism(s) whereby this increase in melanin production (commonly known as tanning) occurs is not well understood. Few studies have examined the molecular consequences of UV on human skin of various racial backgrounds in situ. We investigated the effects of UV on human skin of various races before and at different times after a single 1 minimal erythemal dose UV exposure. We measured the distribution of DNA damage that results, as well as the melanin content/distribution and the expression of various melanocyte-specific genes. The density of melanocytes at the epidermal:dermal junction in different types of human skin are remarkably similar and do not change significantly within 1 wk after UV exposure. The expression of melanocyte-specific proteins (including TYR (tyrosinase), TYRP1 (tyrosinase-related protein 1), DCT (tyrosinase-related protein 2), MART1 (melanoma antigens recognized by T-cells) gp100 (Pmel17/silver), and MITF (micropthalmia transcription factor)) increased from 0 to 7 d after UV exposure, but the melanin content of the skin increased only slightly. The most significant change, however, was a change in the distribution of melanin from the lower layer upwards to the middle layer of the skin, which was more dramatic in the darker skin. These results provide a basis for understanding the origin of different skin colors and responses to UV within different races.
Tadokoro
Taketsugu
T
Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Yamaguchi
Yuji
Y
Batzer
Jan
J
Coelho
Sergio G
SG
Zmudzka
Barbara Z
BZ
Miller
Sharon A
SA
Wolber
Rainer
R
Beer
Janusz Z
JZ
Hearing
Vincent J
VJ
D044466:Asian People; D044383:Black People; D002452:Cell Count; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000166:cytology; D020460:Melanosomes / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D012880:Skin Pigmentation / Q000528:radiation effects*; D013194:Staining and Labeling; D014018:Tissue Distribution; D014466:Ultraviolet Rays; D044465:White People
D008543:Melanins; D011506:Proteins