Volume 103, Issue 1 pp. 88-93

Geniposide Enhances Melanogenesis by Stem Cell Factor/c-Kit Signalling in Norepinephrine-Exposed Normal Human Epidermal Melanocyte

Wen-Jun Lan

Wen-Jun Lan

Laboratory for Drug Discovery, Shandong Institute of Light Industry, Jinan, China,

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Hai-Yan Wang

Hai-Yan Wang

Laboratory for Drug Discovery, Shandong Institute of Light Industry, Jinan, China,

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Wei Lan

Wei Lan

College of Pharmacy, Xinjiang Medical University, Urumqi, China, and

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Ke-Yu Wang

Ke-Yu Wang

Department of Dermatology, Qilu Hospital, Shandong University, Jinan, China

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First published: 28 June 2008
Citations: 23
Author for correspondence: Wen-Jun Lan, Laboratory for Drug Discovery, Shandong Institute of Light Industry, Jinan 250353, China (fax +86-531-89631191, e-mail [email protected]).

Abstract

Abstract: Geniposide is an iridoid glycoside isolated from the fruit of Gardenia jasminoides Ellis used as a Chinese traditional medicine for treatment of generalized vitiligo. Stem cell factor from keratinocyte recognizes and activates its receptor c-kit carried by melanocyte to potent enhance melanocytic melanogenesis that can be suppressed by norepinephrine. This study addresses the action and mechanism of geniposide enhancing melanogenesis in norepinephrine-exposed normal human epidermal melanocyte. Flow cytometry results from this study exhibited the augmentation effect of geniposide on production of c-kit receptor by norepinephrine-exposed normal human epidermal melanocyte. However, geniposide did not affect the production of stem cell factor by norepinephrine-exposed normal human epidermal keratinocyte assessed by cellular enzyme-linked immunosorbent assay (ELISA). ELISA indicated that at the presence of stem cell factor, geniposide was capable of elevating the level of extracellular signal-regulated kinase 1/2 phosphorylation within norepinephrine-exposed normal human epidermal melanocyte, which is known to be involved in stem cell factor/c-kit downstream signalling. And inhibition of c-kit with inhibitory antibody K44.2 completely blocked the increase in geniposide-stimulated extracellular signal-regulated kinase 1/2 phosphorylation. In addition, spectrophotometry demonstrated the enhancement effect of geniposide on melanogenesis (tyrosinase activity and melanin production) in norepinephrine-exposed normal human epidermal melanocyte at the presence of stem cell factor, which was blocked by c-kit inhibitory antibody K44.2. Data from this study suggest that geniposide can enhance melanogenesis by stem cell factor/c-kit signalling in which the expression of c-kit receptor is augmented in norepinephrine-exposed normal human epidermal melanocyte.

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