Melanocyte precursors express elastin binding protein and elastin-derived peptide (VGVAPG) stimulates their melanogenesis and dendrite formation.
BACKGROUND
In congenital or acquired dermal melanocytosis, attachment of melanocyte with elastic fiber was shown in electron microscopy of unknown biological meaning. We hypothesize elastin-derived peptide may play a role in activating dermal melanocyte precursors.


OBJECTIVE
This study was designed to determine: (i) whether melanocyte precursors express elastin binding protein (EBP); (ii) ontogenic expression of EBP and elastin in murine embryonic skin; (iii) the effects of elastin-derived peptide (VGVAPG) on melanocyte precursors.


METHODS
Using immunohistochemistry or Western blot to identify EBP on murine embryonic sections, neural crest cell (NCC) primary culture explants, or two melanocyte precursor cell lines, NCCmelb4 and NCCmelan5. NCC explants or cells were treated with VGVAPG to compare its effect on proliferation, dendrite formation, melanosome maturation and tyrosinase mRNA expression of melanocyte precursors.


RESULTS
EBP was immunostained on c-kit+ melanocyte precursors. 67kDa EBP protein was immunoblotted on NCCmelb4 and NCCmelan5 cells. EBP was expressed early at embryonic day (E) 9.5, but elastin appeared later at E12.5 skin. VGVAPG increased DOPA-positive cell number and enhanced their dendrite formation in NCC explants. Electron microscopy showed advanced melanosome maturation in NCC explants or cells treated with VGVAPG. VGVAPG enhanced tyrosinase mRNA expression in NCCmelan5 cells.


CONCLUSIONS
Melanocyte precursors expressed EBP. VGVAPG stimulated their melanogenesis and dendrite formation. In the developmental journey interaction between elastin and EBP-expressed melanocyte precursors in embryos happened mainly since the stage of tertiary melanoblasts. These findings first provide biological evidences for the interaction between melanocyte and elastic fiber.
Chang
Chung-Hsing
CH
Department of Dermatology, Buddhist Tzu Chi General Hospital and Graduate Institute of Medicine, Tzu Chi University, School of Medicine, Chung-Yang Road, Hualien, Taiwan. chchang@tzuchi.com.tw
Kawa
Yoko
Y
Tsai
Rong-Kung
RK
Shieh
Jia-Hung
JH
Lee
Jeng-Woei
JW
Watabe
Hidenori
H
Kawakami
Tamihiro
T
Soma
Yoshinao
Y
Tajima
Shingo
S
Mizoguchi
Masako
M
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004549:Elastin / Q000494:pharmacology; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D007150:Immunohistochemistry; D008544:Melanocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D020460:Melanosomes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D014442:Monophenol Monooxygenase / Q000235:genetics; D009842:Oligopeptides / Q000494:pharmacology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*
D017931:DNA Primers; D009842:Oligopeptides; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C054901:elastin-binding proteins; D004295:Dihydroxyphenylalanine; D004549:Elastin; C042635:valyl-glycyl-valyl-alanyl-prolyl-glycine; D014442:Monophenol Monooxygenase