Trans-Zeatin attenuates ultraviolet induced down-regulation of aquaporin-3 in cultured human skin keratinocytes

Abstract

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.

Intrinsic versus Extrinsic Aging: A Histopathological, Morphometric and Immunohistochemical Study of Estrogen Receptor β and Androgen Receptor

“…However, the downregulation noted in sun-unprotected skin with advancing age may provide evidence that deficient receptor expression occurs in both the intrinsic and extrinsic aging processes. This finding corresponds to the fact that skin aging is a degenerative process whereby alterations due to the passage of time (chronological/intrinsic aging) are superimposed with effects produced by environmental factors, the most important of which is UV radiation [56,57]. …”

Cytokinins: Wide-Spread Signaling Hormones from Plants to Humans with High Medical Potential

“…Ji et al tested the anti-aging protective effect of trans-zeatin in the immortalized HaCaT keratinocytes against UV irradiation. Trans-zeatin induced aquaporin-3 (AQP3) expression and attenuated the UV-induced loss of AQP3, and UV-induced decreased water permeability in HaCaT cells, in addition to the inhibition of the activation of the UV-induced MEK/ERK pathway, which plays an important role in UV-induced AQP3 loss [ 104 ].…”

<p>The Extract from <em>Acidosasa longiligula</em> Alleviates in vitro UV-Induced Skin Cell Damage via Positive Regulation of Thioredoxin 1</p>

“…As previously described, [21][22][23][24][25] the primary skin keratinocytes from American Type Culture Collection (ATCC) were maintained in Dulbecco's Modified Eagle Medium (DMEM) (Invitrogen Life Technologies, Carlsbad, CA, USA) with 10% fetal bovine serum (FBS) (Biomeda, Foster city, CA, USA) and 1% penicillin/streptomycin/glutamine (Gibco/Invitrogen, Carlsbad, CA, USA), in a humidified incubator with 5% CO 2 at 37°C. UV radiation equipment and procedures have been described previously.…”

“…The detailed protocols were previously described. 22,24 Reactive Oxygen Species (ROS) Detection As described in our previous studies, [23][24][25] the cellular ROS content was assessed by fluorescence-activated cell sorting (FACS; Beckton Dickinson FACScan, Suzhou, China) using the fluorescent dye dihydrorhodamine (DHR). All fluorescent intensities were normalized to an untreated control group.…”