Enhanced fibrillin-2 expression is a general feature of wound healing and sclerosis: potential alteration of cell attachment and storage of TGF-beta.
Wound healing and sclerosis are characterized by an increase of extracellular matrix proteins, which are characteristically expressed in the embryo-fetal period. We analyzed the expression of fibrillin-2, which is typically found in embryonic tissues, but only scarcely in adult skin. In wound healing and sclerotic skin diseases such as lipodermatosclerosis and scleroderma, a marked increase of fibrillin-2 expression was found by immunohistology. Double labelling of fibrillin-2 and tenascin-C, which is also expressed in wound healing and sclerosis, showed co-localization of both proteins. Solid-phase and slot blot-overlay assays showed a dose-dependent binding of the recombinant N-terminal half of fibrillin-2 (rFBN2-N) to tenascin-C. Real-time PCR showed an increase of the fibrillin-2 gene expression in cell culture triggered by typical mediators for fibroblast activation such as serum, IL-4, and TGF-beta. By contrast, prolonged hypoxia is not associated with changes in fibrillin-2 expression. Tenascin-C is an anti-adhesive substrate for fibroblasts, whereas fibrillin-2 stimulates cell attachment. Attachment assays using mixed substrates showed decreased cell attachment when tenascin-C and rFBN2-N were coated together, compared with the attachment to rFBN2-N alone. Fibrillins are involved in storage and activation of TGF-beta. Immunohistology with an antibody against the latency-associated peptide (LAP (TGF-beta1)) showed a marked increase of inactive LAP-bound TGF-beta1 in wound healing and sclerotic skin whereas normal skin showed only a weak expression. Double immunofluorescence confirmed a partial colocalization of both proteins. In conclusion, we show that a stimulation of the fibrillin-2 expression is a characteristic feature of fibroblasts present in wound healing and sclerosis, which may be involved in the alteration of cell attachment and storage of inactive TGF-beta in the matrix.
Brinckmann
Jürgen
J
Department of Dermatology, University of Lübeck, Lübeck, Germany. brinckmann@molbio.uni-luebeck.de
Hunzelmann
Nico
N
Kahle
Birgit
B
Rohwedel
Jürgen
J
Kramer
Jan
J
Gibson
Mark A
MA
Hubmacher
Dirk
D
Reinhardt
Dieter P
DP
D002448:Cell Adhesion; D015687:Cell Hypoxia; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005109:Extracellular Matrix / Q000378:metabolism; D000071840:Fibrillin-2; D000071837:Fibrillins; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D015847:Interleukin-4 / Q000494:pharmacology; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012594:Scleroderma, Localized / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012598:Sclerosis; D012867:Skin / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D019063:Tenascin / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D014945:Wound Healing
D016895:Culture Media, Serum-Free; C000605723:FBN2 protein, human; D000071840:Fibrillin-2; D000071837:Fibrillins; D008840:Microfilament Proteins; D019063:Tenascin; D016212:Transforming Growth Factor beta; D015847:Interleukin-4