Decorin-Expressing Adenovirus Decreases Collagen Synthesis and Upregulates the MMP Expression in Keloids; Implication for Reversing Pathologic Fibrosis

Abstract

Background Decorin is a natural neutralizer of TGF-β1 and reduced synthesis of decorin has been associated with the dermal scars, and therefore an increase of decorin expression appears to reduce scar tissue. To investigate the therapeutic potentials of decorin-expressing replication-incompetent adenovirus (dE1-RGD/GFP/DCN) for keloid and hypertrophic scars, we examined the effects of dE1-RGD/GFP/DCN on the expression levels of type I and III collagen as well as MMP-1 and −3 in human dermal fibroblast (HDFs) and keloid-derived fibroblast (KFs) cell lines.

Methods Decorin expressions were examined by immunofluorescence assay in keloid tissues. HDFs and KFs were infected with dE1-RGD/GFP/DCN or control virus, and protein levels of decorin and secreted TGF-ß1 were assessed by ELISA, while mRNA levels of collagen type I, collagen III, MMP-1, MMP-3 by real time RT-PCR. Additionally, the expression levels of major extracellular matrix (ECM) were investigated by immunohistochemistry in keloid spheroids transduced with dE1-RGD/GFP/DCN.

Results Lower expression of decorin was examined in the keloid region compared to the adjacent normal tissues. Treatment with dE1-RGD/DFP/DCN decreased mRNA levels of type I collagen in the TGF-β (10 ng/ml)-treated HDFs and KFs and TGF-β protein expression in the HDFs. In addition, the expression of MMP-1 and-3 mRNA was strongly upregulated in KFs and TGF-β-treated HDFs after treatment with dE1-RGD/DFP/DCN. Moreover, expression of major ECMs such as type I collagen, fibronectin, and elastin were significantly reduced in keloid spheroids transduced with dE1-RGD/DFP/DCN.

Conclusion These results support the use of decorin-expressing adenovirus in gene therapy protocols to lower collagen synthesis in KFs, as this decrease is a highly desirable effect for the treatment of keloids.