Differentiated keratinocytes are responsible for TNF-alpha regulated production of macrophage inflammatory protein 3alpha/CCL20, a potent chemokine for Langerhans cells.
The recruitment of immature dendritic cells into the epidermis is a key step in the development of cutaneous immunity, although the mechanism remains to be clarified. Recently, it was reported that both macrophage inflammatory protein 3alpha (MIP-3alpha)/CCL20 produced by keratinocytes and TNF-alpha are important in recruiting Langerhans cells (LC) to the epidermis. In this study, we examined the production of MIP-3alpha by human keratinocytes stimulated with TNF-alpha. Cultured keratinocytes showed enhanced expression of MIP-3alpha mRNA and protein when stimulated with TNF-alpha. In addition, conditioned medium from TNF-alpha-stimulated keratinocyte cultures induced the migration of L1.2 cells expressing CCR6. We next examined the production of MIP-3alpha in stratified keratinocytes and found that, in contrast to non-stratified keratinocytes, stimulation with TNF-alpha increased the expression of MIP-3alpha mRNA and protein. Moreover, skin samples grown in organ culture and treated with TNF-alpha showed MIP-3alpha in the keratinocytes of the spinous layer, but not in the basal layer, by immunofluorescence staining. Based on these results, we postulate that MIP-3alpha produced by keratinocytes in the spinous layer in response to TNF-alpha stimulation is a key chemokine responsible for the epidermal recruitment of Langerhans cells.
Tohyama
M
M
Department of Dermatology, Ehime University School of Medicine, Shigenobucho, Onsengun, Ehime 791-0295, Japan. tohm@e.ehime-u.ac.jp
Shirakara
Y
Y
Yamasaki
K
K
Sayama
K
K
Hashimoto
K
K
D002454:Cell Differentiation; D002478:Cells, Cultured; D054418:Chemokine CCL20; D019742:Chemokines, CC / Q000235:genetics*; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D019402:Macrophage Inflammatory Proteins / Q000235:genetics*; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000235:genetics; D054399:Receptors, CCR6; D019707:Receptors, Chemokine; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000166:cytology* / Q000187:drug effects; D012879:Skin Physiological Phenomena; D014158:Transcription, Genetic / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
C108355:CCL20 protein, human; C106311:CCR6 protein, human; D054418:Chemokine CCL20; D019742:Chemokines, CC; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger; D054399:Receptors, CCR6; D019707:Receptors, Chemokine; D014409:Tumor Necrosis Factor-alpha