Chen N, Hu Y, Li WH et al.The role of keratinocyte growth factor in melanogenesis: a possible mechanism for the initiation of solar lentigines. Exp Dermatol 19:865-872
ABSTRACT Solar lentigines (SLs) are hyperpigmentary lesions presented on sun-exposed areas of the skin and associated with ageing. The molecular mechanism of SL initiation is not completely understood. Ultraviolet B (UVB) stimulates keratinocytes to produce interlukin-1 alpha (IL-1α), which then induces keratinocyte growth factor (KGF) secretion; therefore, we examined their possible roles in the induction of SLs. We found that KGF increases pigment production in both pigmented epidermal equivalents and human skin explants. In addition, UVB exposure increases KGF expression, and KGF treatment induces tyrosinase (TYR) expression in primary melanocytes. The KGF-induced pigmentary changes were confirmed using pigmented Yucatan swine, and human skins grafted onto immuno-deficient mice. In both model systems, the topical treatment with KGF, alone or in combination with IL-1α, resulted in the in vivo formation of hyperpigmentary lesions with increased pigment deposition and elongated rete ridges, which resemble the histological features of human SLs. Preliminary immunohistochemical analysis of human skins showed a moderate increase in KGF, and a strong induction in KGF receptor (KGFR) in SL lesions. In summary, KGF increases pigment production and deposition in vitro and in vivo. Moreover, we show for the first time the in vivo generation of hyperpigmentary lesions with histological resemblance to human SLs and indicate the involvement of KGF/KGFR in the molecular pathology of human SLs.
- SourceAvailable from: Tomohisa Hirobe
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- "KGF is secreted from cultured stromal fibroblasts derived from skin and gastrointestinal tract and is expressed in vivo in dermal, but not epidermal cells . This paracline growth factor, however, is also effective for stimulating the melanogenesis   and melanosome transfer from human melanocytes to keratinocytes . However, the role of KGF in the proliferation and differentiation of melanocytes is not known. "
ABSTRACT: BACKGROUND: Although keratinocyte-derived factors are known to promote the proliferation and differentiation of human epidermal melanocytes, it is not fully understood whether fibroblast-derived factors work in a similar way. OBJECTIVE: The aim of this study is to clarify whether fibroblast-derived factors are involved in regulating the proliferation and differentiation of human melanocytes with or without keratinocytes using serum-free culture system. METHODS: Human epidermal melanoblasts and melanocytes were cultured in a serum-free growth medium supplemented with fibroblast-derived factors such as keratinocyte growth factor (KGF) with or without keratinocytes, and the effects of KGF on the proliferation and differentiation of melanocytes were studied. RESULTS: KGF stimulated the proliferation of melanoblasts in the presence of dibutyryl cAMP (DBcAMP), basic fibroblast growth factor (bFGF), transferrin (Tf), and endothelin-1 (ET-1). Although KGF stimulated the differentiation, melanogenesis, and dendritogenesis in the presence of DBcAMP, Tf, and ET-1 without keratinocytes, KGF required the presence of keratinocytes for the stimulation of melanocyte proliferation. CONCLUSION: These results suggest that fibroblast-derived KGF stimulates the proliferation of human melanoblasts in synergy with cAMP, bFGF, Tf, and ET-1, the differentiation of melanocytes in synergy with cAMP, Tf, and ET-1, and the proliferation of melanocytes in synergy with cAMP, Tf, ET-1, and undefined keratinocyte-derived factors.Journal of dermatological science 04/2013; 71(1). DOI:10.1016/j.jdermsci.2013.03.012 · 3.34 Impact Factor
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- "Using topical KGF treatment we created in vivo hyperpigmentary lesions, with histological features similar to human SLs. We suggested that KGF is involved in the initiation of hyperpigmentary lesions . Therefore we analyzed KGF and KGFR levels in human SLs. "
ABSTRACT: Solar lentigines (SLs) are macular hyperpigmented lesions associated with sun exposure and age. Histopathologically, SLs are defined by a hyperpigmented basal layer and elongated rete ridges. The molecular mechanisms involved in the formation and the development of SLs are not completely understood. Our earlier data show that keratinocyte growth factor (KGF) induces hyperpigmentary lesions with histological resemblance to SLs. To investigate the association of KGF/KGF receptor (KGFR) and other pigmentary genes with the progression of SL development. To better understand the possible role of KGF in the pathology of SLs. Archived human skin biopsies (24 SLs and 14 healthy skins) were studied using immunohistochemistry for KGF/KGFR, proliferation marker Ki67, stem cell marker keratin-15 (K15), tyrosinase (TYR), stem cell factor (SCF), and protease-activated receptor-2 (PAR-2). An increase in TYR-positive cells and expression was found throughout SL progression, as compared to normal skin. The levels of KGF, KGFR, SCF, Ki67 and PAR-2 varied during SL progression. Ki67, K15 and KGF/KGFR were significantly upregulated at early-mid SL stages. The latest-stage SLs expressed the lowest levels of KGF, KGFR, SCF, Ki67 and PAR-2. The upregulation of KGF/KGFR might induce the formation of rete ridges and hyperpigmentation. The reduced levels of all examined proteins (except TYR and K15) suggest a possible inactive status (dormancy or quiescence) of advanced lesions.Journal of dermatological science 08/2010; 59(2):91-7. DOI:10.1016/j.jdermsci.2010.06.006 · 3.34 Impact Factor
Conference Paper: Performance analysis of network and database transactions in a CIMsystem[Show abstract] [Hide abstract]
ABSTRACT: A Petri-net-based integrated model for the performance analysis of network and database transactions, generated by manufacturing clients for the computer resources, which are acting as the servers, is discussed. A Petri-net-based multifaceted integrated modeling (PNBMIM) approach to investigate the relevant system integration issues between the logical and the physical access of the information in the manufacturing system is described. The PNBMIM approach proposes an integrated conceptual framework for modeling and performance (both structural and behavioral) analysis of data flow and communication flow. This framework should provide some answers to the impact of relative time-scales on the coupling and decoupling of the various levels of a computer integrated manufacturing (CIM) system and identify the time-scales where integration becomes importantRobotics and Automation, 1991. Proceedings., 1991 IEEE International Conference on; 05/1991