The osmolyte taurine protects against ultraviolet B radiation-induced immunosuppression.
Organic osmolytes, such as taurine, are involved in cell volume homeostasis and cell protection. Epidermal keratinocytes possess an osmolyte strategy, i.e., they take up taurine upon hyperosmotic stress and express the corresponding transporter TAUT. UVB irradiation also triggers taurine uptake and TAUT expression in this cell type. We therefore asked whether taurine plays a role in photoprotection. By using a TAUT-deficient mouse model, lack of taurine in the skin was found to cause a significantly higher sensitivity to UVB-induced immunosuppression. This was not due to an increased generation or decreased repair of UVB-induced DNA photoproducts in the skin of these animals. Instead, decreased skin taurine levels were associated with an increased formation of the soluble immunosuppressive molecule platelet-activating factor (PAF) from the membranes of UVB-irradiated epidermal cells. Blocking PAF activity in taut-deficient mice with a PAF receptor antagonist abrogated their increased sensitivity to UVB-induced immunosuppression. Moreover, taut -/- mice were more sensitive to PAF-mediated immunosuppression than taut +/+ mice. These data suggest that taurine uptake by epidermal cells prevents undue PAF formation, and thereby photoimmunosuppression. Thus, similar to nucleotide excision repair, taurine uptake is critically involved in photoprotection of the skin.
Rockel
Nicole
N
Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Düsseldorf, Germany.
Esser
Charlotte
C
Grether-Beck
Susanne
S
Warskulat
Ulrich
U
Flögel
Ulrich
U
Schwarz
Agatha
A
Schwarz
Thomas
T
Yarosh
Daniel
D
Häussinger
Dieter
D
Krutmann
Jean
J
D000818:Animals; D002478:Cells, Cultured; D004260:DNA Repair / Q000528:radiation effects; D005260:Female; D020022:Genetic Predisposition to Disease; D007165:Immunosuppression Therapy; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000528:radiation effects; D007801:Langerhans Cells / Q000528:radiation effects; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009997:Osmotic Pressure / Q000528:radiation effects; D010972:Platelet Activating Factor / Q000378:metabolism / Q000528:radiation effects; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors; D011740:Pyrimidine Dimers / Q000096:biosynthesis / Q000528:radiation effects; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors; D012867:Skin / Q000166:cytology / Q000276:immunology* / Q000378:metabolism / Q000528:radiation effects*; D013654:Taurine / Q000172:deficiency / Q000378:metabolism / Q000502:physiology*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D000099247:Taurine Transporters