NTU Undergraduates' research April 2014 - Biosciences | Seite 47

The role of transforming growth factor-β and tissue transglutaminase
during wound repair.
Abstract
Transforming growth factor beta (TGF-β) is a fibrogenic cytokine that plays an important role during wound repair. It is
synthesised in a biologically inactive form, and its activation is required in order for it to exert its effects upon wound
healing. It has been revealed that its activation may be caused by factors including integrin’s and thrombospondin.
Increasing evidence suggests tissue transglutaminase (TG2) may also be involved in this activation, by cross-linking large
latent TGF-β into the extracellular matrix and releasing the active form, however this has never been demonstrated
during wound healing in vitro. It has been implied that TG2 may help fibroblasts migrate into the wounded area in an
independent mechanism to its cross-linking ability. To determine if TGF-β is activated during wound repair and the role
TG2 plays on this activation, fibrosis was stimulated in vitro upon NRK52 epithelial cells and Swiss 3T3 fibroblasts. Mink
lung epithelial cells transfected with plasminogen activator inhibitor-1 promoter-luciferase construct were used to
measure active TGF-β levels. In addition to this, fibroblast migration was observed using a cell viability assay. The
results revealed that TGF-β is activated during wound repair and TG2 aids in this activation. Extracellular TG2 plays a
role in cell migration and wound closure, but inhibiting TG2 did not cause a decrease in cell migration. Therefore it is
unclear whether TG2 does aid in cell migration or if another factor is also involved.
Key words: Wound repair, Transforming growth factor beta (TGF-β), Fibrosis, Tissue Transglutaminase (TG2), Cell
migration,
Wound
closure.

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