Dissanayake N S, Mason R S
Department of Physiology, University of Sydney, New South Wales 2006, Australia.
J Endocrinol. 1998 Oct;159(1):153-63. doi: 10.1677/joe.0.1590153.
The adaptive responses in skin to ultraviolet (UV) radiation include increased cornification of keratinocytes and increased synthesis and distribution of melanin by melanocytes. The possible involvement of paracrine factors in the generation of these responses was studied in a novel two-stage culture model. Human melanocytes or keratinocytes were first irradiated or sham-irradiated and then the conditioned media collected from these cells after 24 h were used to treat unirradiated skin cells. Immunofluorescent staining for transforming growth factor (TGF)-beta1 was increased in UV-irradiated keratinocytes compared with sham-irradiated cells. Increased TGF-beta1 was also detected in the culture media of irradiated keratinocytes. Treatment of unirradiated keratinocytes with conditioned media collected from UV-irradiated keratinocytes resulted in increased absolute numbers and percentages of cornified envelopes per well compared with treatment with conditioned media from sham-irradiated keratinocytes. The magnitude of this effect increased with increased dose of initial irradiation. The effects of conditioned media from UVR-treated cells were mimicked by authentic TGF-beta1. Treatment of conditioned media from irradiated cells with an antibody shown to neutralise the effects of TGF-beta1 but not with a non-immune antibody of similar isotype, abolished this bioactivity of the conditioned media from UV-irradiated cells. Immunofluorescent staining for ACTH was also increased in UV-irradiated keratinocytes. Conditioned media from UV-irradiated keratinocytes increased tyrosinase activity of unirradiated melanocytes, an effect which was mimicked by authentic ACTH. This bioactivity of conditioned media from irradiated keratinocytes was abolished in the presence of an antibody which neutralised the activity of ACTH but not MSH. These results provide evidence to support the involvement of TGF-beta1 and ACTH in the cornification and pigmentary responses respectively of skin cells after UV exposure.
皮肤对紫外线（UV）辐射的适应性反应包括角质形成细胞的角质化增加以及黑素细胞中黑色素合成和分布的增加。在一种新型的两阶段培养模型中研究了旁分泌因子在这些反应产生过程中的可能作用。首先对人黑素细胞或角质形成细胞进行照射或假照射，然后在24小时后收集这些细胞的条件培养基，用于处理未照射的皮肤细胞。与假照射的细胞相比，紫外线照射的角质形成细胞中转化生长因子（TGF）-β1的免疫荧光染色增加。在照射的角质形成细胞的培养基中也检测到TGF-β1增加。用从紫外线照射的角质形成细胞收集的条件培养基处理未照射的角质形成细胞，与用假照射的角质形成细胞的条件培养基处理相比，每孔中角质包膜的绝对数量和百分比增加。这种效应的大小随着初始照射剂量的增加而增加。紫外线处理细胞的条件培养基的作用可被天然TGF-β1模拟。用一种能中和TGF-β1作用的抗体处理照射细胞的条件培养基，而不用同型的非免疫抗体处理，可消除紫外线照射细胞条件培养基的这种生物活性。紫外线照射的角质形成细胞中促肾上腺皮质激素（ACTH）的免疫荧光染色也增加。紫外线照射的角质形成细胞的条件培养基增加了未照射黑素细胞的酪氨酸酶活性，这种作用可被天然ACTH模拟。在存在中和ACTH活性但不中和促黑素（MSH）活性的抗体的情况下，照射角质形成细胞的条件培养基的这种生物活性被消除。这些结果提供了证据，支持TGF-β1和ACTH分别参与紫外线暴露后皮肤细胞的角质化和色素沉着反应。
