Dermal fibroblasts derived from fetal and postnatal humans exhibit distinct responses to insulin like growth factors.
BACKGROUND
It has been well established that human fetuses will heal cutaneous wounds with perfect regeneration. Insulin-like growth factors are pro-fibrotic fibroblast mitogens that have important roles in both adult wound healing and during development, although their relative contribution towards fetal wound healing is currently unknown. We have compared responses to IGF-I and -II in human dermal fibroblast strains derived from early gestational age fetal (<14 weeks) and developmentally mature postnatal skin to identify any differences that might relate to their respective wound healing responses of regeneration or fibrosis.


RESULTS
We have established that the mitogenic response of fetal cells to both IGF-I and -II is much lower than that seen in postnatal dermal fibroblasts. Further, unlike postnatal cells, fetal cells fail to synthesise collagen in response to IGF-I, whereas they do increase synthesis in response to IGF-II. This apparent developmentally regulated difference in response to these related growth factors is also reflected in changes in the tyrosine phosphorylation pattern of a number of proteins. Postnatal cells exhibit a significant increase in phosphorylation of ERK 1 (p44) in response to IGF-I and conversely the p46 isoform of Shc on IGF-II stimulation. Fetal cells however only show a significant increase in an unidentified 100 kDa tyrosine-phosphorylated protein on stimulation with IGF-II.


CONCLUSIONS
Dermal fibroblasts exhibit different responses to the two forms of IGF depending on their developmental maturity. This may relate to the developmental transition in cutaneous wound healing from regeneration to fibrosis.
Rolfe
Kerstin J
KJ
RAFT Institute of Plastic Surgery, Leopold Muller Building, Mount Vernon Hospital, Northwood Middlesex, UK. rolfek@raft.ac.uk
Cambrey
Alison D
AD
Richardson
Janette
J
Irvine
Laurie M
LM
Grobbelaar
Adriaan O
AO
Linge
Claire
C
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000378:metabolism; D020405:Dermis; D005333:Fetus / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D047468:Immunoprecipitation; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D012867:Skin / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013002:Somatomedins / Q000494:pharmacology*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
D048868:Adaptor Proteins, Signal Transducing; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D013002:Somatomedins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D003094:Collagen; D017526:Receptor, IGF Type 1; D048052:Mitogen-Activated Protein Kinase 3