Hauttypen, Hautpigmentierung und Melaninsynthese: wichtige Instrumente der menschlichen Haut zur Anpassung an die UV-Strahlung

 

 Permissions and Reprints

Zusammenfassung

Verschiedene Evolutionstheorien befassen sich mit der Entwicklung der Hautfarben, einem der wichtigsten individuellen Merkmale des Menschen. Die am besten etablierte Theorie geht von einer Anpassung an die jeweilige solare UV-Strahlung in einem bestimmten geografischen Gebiet über natürliche Selektionsmechanismen aus. Demnach muss die Haut einerseits ausreichend pigmentiert sein, um einen wirksamen Schutz vor den schädlichen Einwirkungen der UV-Strahlung zu gewährleisten, andererseits muss aber auch genügend Strahlung die Hautzellen erreichen können, um wichtige biologische Wirkungen (u. a. die kutane Vitamin D-Synthese) auszuüben. Wichtige Instrumente, um in Abhängigkeit von der Intensität der solaren UV-Strahlung beide Anforderungen zu erfüllen, sind die Entwicklung der Hautfarben und die Regulation der Melaninsynthese. Die Hautpigmentierung läuft über komplexe Reaktionsschritte ab. Das wichtigste Pigment der menschlichen Hautfarbe ist Melanin, das in einer mehrstufigen Reaktion aus der Aminosäure Tyrosin synthetisiert wird. Produziert wird Melanin in Melanozyten in auf die Melaninproduktion spezialisierten Zellorganellen, den Melanosomen. Die Synthese wird durch einen komplexen Regulationsmechanismus gesteuert, an dem verschiedene Botenstoffe wie z. B. α-MSH entscheidend beteiligt sind. Daneben wird die noch nicht vollständig verstandene Regulation der Hautpigmentierung von vielen weiteren Faktoren beeinflusst, darunter genetische Varianten der an der Melaninsynthese beteiligten Enzyme bzw. Strukturproteine. Dieser Artikel gibt einen aktuellen Überblick über Bedeutung und Regulation von Hautpigmentierung und Melaninsynthese.

Abstract

Distinct theories exist to explain the development of skin pigmentation, one of a person’s most individual characteristics, during human evolution. A well accepted theory is the adaptation of the skin pigmentation depending on the solar UV radiation in a particular geographic area via natural selection. A sufficient pigmentation is necessary to protect human skin from harmful UV radiation. On the other hand, an adequate UV radiation must reach the skin to promote important biological activities such as cutaneous vitamin D production. To maintain this on the intensity of UV radiation depending equilibrium, the development of different skin colors and a complex regulation of melanin synthesis are important mechanisms. The most prominent pigment in human skin is melanin that is produced during a multi- step biochemical reaction from the amino acid tyrosine as precursor. This synthesis is localized in melanosomes, specific cell organelles in melanocytes, and is regulated by complex mechanisms involving different hormones such as α-MSH and many other factors such as genetic variations of enzymes. However, many details of the regulation mechanisms remain unknown. This article summarizes the importance and regulation of human skin pigmentation and melanin synthesis.

• Literatur

• 1 Diamond J. Geography and skin colour. Nature 2005; 435: 283-284
  CrossrefPubMedGoogle Scholar
• 2 Jablonski NG, Chaplin G. The evolution of human skin coloration. Journal of Human Evolution 2000; 39: 57-106
  CrossrefPubMedGoogle Scholar
• 3 Goding CR. Cells in focus Melanocytes: The new Black. International Journal of Biochemistry & Cell Biology 2007; 39: 275-279
  CrossrefPubMedGoogle Scholar
• 4 Uyen LDP, Nguyen DH, Kim EK. Mechanism of skin pigmentation. Biotechnology and Bioprocess Engineering 2008; 13: 383-395
  CrossrefPubMedGoogle Scholar
• 5 Mort RL, Jackson IJ, Patton EE. The melanocyte lineage in development and disease. Development 2015; 142: 1387
  CrossrefPubMedGoogle Scholar
• 6 Yamaguchi Y, Brenner M, Hearing VJ. The regulation of skin pigmentation. J Biol Chem 2007; 282: 27557-27561
  CrossrefPubMedGoogle Scholar
• 7 Scherer D, Kumar R. Genetics of pigmentation in skin cancer – A review. Mutat Res 2010; 705: 141-153
  CrossrefPubMedGoogle Scholar
• 8 Kanitakis J. Anatomy, histology and immunohistochemistry of normal human skin. Eur J Dermatol 2002; 12: 390-399
  PubMedGoogle Scholar
• 9 Shain AH, Bastian BC. From melanocytes to melanomas. Nat Rev Cancer 2016; 16: 345-358
  CrossrefPubMedGoogle Scholar
• 10 Yamaguchi Y, Itami S, Watabe H. et al. Mesenchymal–epithelial interactions in the skin: increased expression of dickkopf1 by palmoplantar fibroblasts inhibits melanocyte growth and differentiation. J Cell Biol 2004; 165: 275-285
  CrossrefPubMedGoogle Scholar
• 11 Yamaguchi Y, Passerson T, Hoashi T. et al. Dickkopf 1 (DKK1) regulates skin pigmentation and thickness by affecting Wnt/β-catenin signaling in keratinocytes. FSEB J 2016; 4: 1009-1020
  PubMedGoogle Scholar
• 12 Ancans J, Hoogduijn MJ, Thody AJ. Melanosomal pH, pink locus protein and their roles in melanogenesis. J Invest Dermatol 2001; 117: 158-159
  CrossrefPubMedGoogle Scholar
• 13 Sturm RA. Molecular genetics of human pigmentation diversity. Hum Mol Genet 2009; 18: R9-R17
  CrossrefPubMedGoogle Scholar
• 14 Wolf HEM, Boulanger MC, D’Orazio JA. Melanocortin 1 Receptor: Structure, Function, and Regulation. Front Genet 2016; 7: 95
  PubMedGoogle Scholar
• 15 Raghunath A, Sambarey A, Sharma N. et al. A molecular systems approach to modelling human skin pigmentation: identifying underlying pathways and critical components. BMC Res Notes 2015; 8: 170
  CrossrefPubMedGoogle Scholar
• 16 Swift JA. Speculations on the molecular structure of eumelanin. Int J Cosmet Sci 2009; 2: 143-150
  PubMedGoogle Scholar
• 17 Lin JY, Fisher DE. Melanocyte biology and skin pigmentation. Nature 2007; 445: 843-850
  CrossrefPubMedGoogle Scholar
• 18 Tstamali M, Ancans J, Yukitake J. et al. Skin POMC Peptides: Their Actions at the Human MC-1 Receptor and Roles in the Tanning Response. Pigment Cell Res 2000; 13 (Suppl. 08) 125-129
  CrossrefPubMedGoogle Scholar
• 19 Suzuki I, Tada A, Ollmann MM. et al. Agouti Signaling Protein Inhibits Melanogenesis and the Response of Human Melanocytes to α-Melanotropin. J Invest Dermatol 1997; 108: 838-842
  CrossrefPubMedGoogle Scholar
• 20 Millar SE, Miler MW, Stevens ME. et al. Expression and transgenic studies of the mouse agouti gene provide insight into the mechanisms by which mammalian coat color patterns are generated. Development 1995; 121: 3223-3232
  PubMedGoogle Scholar
• 21 Yamaguchi Y, Hearing VJ. Melanocytes and their diseases. Cold Spring Harb Perspect Med 2014; 4: 1-18
  PubMedGoogle Scholar
• 22 Astner S, Anderson R. Skin Phototypes 2003. J Invest Dermatol 2004; 122 DOI: 10.1046/j.1523-1747.2003.22251.x.
  CrossrefPubMedGoogle Scholar