Functional redundancy of extracellular matrix protein 1 in epidermal differentiation.
BACKGROUND
Extracellular matrix protein 1 (ECM1) is a secreted protein expressed in skin. Its dermatological relevance has been highlighted by the discovery of loss-of-function mutations in ECM1 in patients with lipoid proteinosis (LiP).


OBJECTIVE
To determine the role of ECM1 in epidermal differentiation by examining gene and protein expression of epidermal differentiation markers in individuals with LiP and histological assessment of transgenic mouse skin that overexpresses Ecm1a in basal or suprabasal epidermis.


METHODS
Subconfluent, confluent and postconfluent LiP and control keratinocyte cultures were analysed by Northern and Western blotting for differences in expression of differentiation markers. Expression of these markers was analysed in skin of patients with LiP by immunohistochemistry. To study effects of Ecm1 overexpression on epidermal differentiation, transgenic mice were generated under control of either a keratin 14 or an involucrin promoter.


RESULTS
No differential expression of the different markers analysed was observed in LiP keratinocytes compared with controls. No histological differences were found in Ecm1-overexpressing mouse skin compared with wild-type.


CONCLUSIONS
Absence of ECM1 does not lead to differences in epidermal differentiation. Moreover, overexpression of Ecm1a in vivo does not exert dramatic effects on epidermal structure. Collectively, these findings suggest no role of ECM1 in epidermal differentiation.
Sercu
S
S
Labortaory of Molecular Biotechnology, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk/Antwerp, Belgium.
Poumay
Y
Y
Herphelin
F
F
Liekens
J
J
Beek
L
L
Zwijsen
A
A
Wessagowit
V
V
Huylebroeck
D
D
McGrath
J A
JA
Merregaert
J
J
D000328:Adult; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D004817:Epidermis / Q000473:pathology*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D008065:Lipoid Proteinosis of Urbach and Wiethe / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D012867:Skin / Q000378:metabolism / Q000473:pathology
C490607:ECM1 protein, human; D016326:Extracellular Matrix Proteins