Regulation of human skin pigmentation and responses to ultraviolet radiation

Abstract

SummaryPigmentation of human skin is closely involved in protection against environmental stresses, in particular exposure to ultraviolet (UV) radiation. It is well known that darker skin is significantly more resistant to the damaging effects of UV, such as photocarcinogenesis and photoaging, than is lighter skin. Constitutive skin pigmentation depends on the amount of melanin and its distribution in that tissue. Melanin is significantly photoprotective and epidermal cells in darker skin incur less DNA damage than do those in lighter skin. This review summarizes current understanding of the regulation of constitutive human skin pigmentation and responses to UV radiation, with emphasis on physiological factors that influence those processes. Further research is needed to characterize the role of skin pigmentation to reduce photocarcinogenesis and to develop effective strategies to minimize such risks.

Human skin pigmentation, migration and disease susceptibility

“…Darkly pigmented, eumelanin-rich skin protects against considerable damage to DNA caused by UVR [80], and is associated with much lower rates of skin cancer than lightly pigmented skin [81 -84]. The protective effects of eumelanin on DNA structure were established by an experimental study showing that heavily pigmented melanocytes resumed proliferation faster after UVB irradiation than can lightly pigmented ones, and that DNA from lightly pigmented melanocytes was more badly damaged than DNA from heavily pigmented melanocytes after irradiation with increasing doses of UVB [81,85].…”

[6]-Shogaol inhibits melanogenesis in B16 mouse melanoma cells through activation of the ERK pathway

“…It has been reported that skin pigmentation is regulated by a variety of intrinsic and extrinsic factors [7,8] , as well as diverse signaling pathways including protein kinase A (PKA), phosphatidylinositol 3-kinase (PI3K), and mitogen-activated protein kinases (MAPKs) [9][10][11][12][13] . In particular, the MAPK kinase (MEK)/extracellular signal-regulated kinase (ERK) and the PI3K/Akt pathways have been shown to negatively regulate melanin synthesis in melanocytes and melanoma cells [14][15][16][17][18] .…”

P53 sous le soleil

“…Les mélanines sont transmises aux kératinocytes sous forme de petits granules appelés méla-nosomes ( Figure 1B). La pigmentation assure ainsi une protection naturelle du génome kératinocytaire en absorbant les ultraviolets [12]. L'importance de la protection assurée par les mélanines est illustrée par des taux de cancers cutanés significativement plus élevés chez les personnes à peau claire que chez les personnes à peau plus sombre.…”