title: Trans-Zeatin attenuates ultraviolet induced down-regulation of aquaporin-3 in cultured human skin keratinocytes.
abstract: Solar ultraviolet (UV) irradiation is one of the most significant extrinsic factors contributing to skin photoaging. One major characteristic of photoaging induced by UV is water loss of the skin. Water movement across the plasma membrane can occur via two pathways: by diffusion through the lipid bilayer and by membrane-inserted water channels (aquaporins). In this study we demonstrate that UV induces aquaporin-3 (AQP3) downregulation in cultured keratinocytes (HaCaT cells). PD98059 and U0126, MEK/ERK inhibitors, inhibit UV-induced AQP3 loss. Trans-Zeatin (tZ), which alone induces AQP3 expression, attenuates UV-induced loss of AQP3. We found that tZ inhibits UV-induced MEK/ERK activation; the latter serves as the key signal pathway mediating UV-induced AQP3 loss. Using specific AQP3 siRNA knockdown, we found AQP3 is involved in wound healing in human skin keratinocytes. Loss-of-AQP3-mediated delayed wound healing in UV-radiated skin keratinocytes is attenuated by tZ pretreatment. tZ pretreatment also attenuates UV-induced decreased water permeability in HaCaT cells. We concluded that UV radiation downregulates AQP3 in HaCaT cells. MEK/ERK activation is involved in this process. tZ treatment attenuates UV-induced AQP3 loss, in vitro wound healing delay and water permeability decrease. This work provides a new explanation for the anti-photoaging potential of tZ.
authors.affiliation: Department of Dermatology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, P.R. China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ji
authors.forename: Yanli
authors.initials: Y
authors.lastname: Yang
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.forename: Jiping
authors.initials: J
authors.lastname: Xia
authors.forename: Weiling
authors.initials: W
authors.lastname: Sun
authors.forename: Zhonglan
authors.initials: Z
authors.lastname: Su
authors.forename: Liting
authors.initials: L
authors.lastname: Yu
authors.forename: Shijun
authors.initials: S
authors.lastname: Shan
authors.forename: Shaoheng
authors.initials: S
authors.lastname: He
authors.forename: Lei
authors.initials: L
authors.lastname: Cheng
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Wan
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Bi
mesh_terms: D051400:Aquaporin 3 / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015603:Keratinocytes / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays; D014867:Water / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects / Q000528:radiation effects; D015026:Zeatin / Q000737:chemistry / Q000494:pharmacology
chemical_list: C496027:AQP3 protein, human; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011725:Pyridines; D034741:RNA, Small Interfering; D014867:Water; D051400:Aquaporin 3; D015026:Zeatin; D020929:Mitogen-Activated Protein Kinase Kinases; C093642:SB 203580