Topical Application of Recombinant Type VII Collagen Incorporates Into the Dermal–Epidermal Junction and Promotes Wound Closure

Abstract

Patients with recessive dystrophic epidermolysis bullosa (RDEB) have incurable skin fragility, blistering, and skin wounds due to mutations in the gene that codes for type VII collagen (C7) that mediates dermal-epidermal adherence in human skin. In this study, we evaluated if topically applied human recombinant C7 (rC7) could restore C7 at the dermal-epidermal junction (DEJ) and enhance wound healing. We found that rC7 applied topically onto murine skin wounds stably incorporated into the newly formed DEJ of healed wounds and accelerated wound closure by increasing re-epithelialization. Topical rC7 decreased the expression of fibrogenic transforming growth factor-β2 (TGF-β2) and increased the expression of anti-fibrogenic TGF-β3. These were accompanied by the reduced expression of connective tissue growth factor, fewer α smooth muscle actin (α-SMA)-positive myofibroblasts, and less deposition of collagen in the healed neodermis, consistent with less scar formation. In addition, using a mouse model in which skin from C7 knock out mice was grafted onto immunodeficient mice, we showed that applying rC7 onto RDEB grafts with wounds restored C7 and anchoring fibrils (AFs) at the DEJ of the grafts and corrected the dermal-epidermal separation. The topical application of rC7 may be useful for treating patients with RDEB and patients who have chronic skin wounds.

Gentamicin induces functional type VII collagen in recessive dystrophic epidermolysis bullosa patients

“…While it is possible that the gentamicin-treated sites had lower bacterial counts, the generation of new type VII collagen and AFs at the DEJ only in the gentamicintreated sites strongly suggests that the likely major mechanism by which gentamicin improved clinical wound healing was by its ability to read through PTCs and generate new type VII collagen and AFs. This is consistent with our previous study showing that topical recombinant type VII collagen promotes wound closure (8).…”

“…These have included intradermal injection of allogeneic dermal fibroblasts or gene-corrected RDEB fibroblasts (11,14,16), intradermal injection of lentiviral vectors expressing type VII collagen (48), intradermal injection or topical application of recombinant type VII collagen protein (6)(7)(8), intravenous injection of type VII collagen protein itself or fibroblasts that synthesize and secrete type VII collagen (9,10,12), transplantation of bone marrow stem cells, and gene-corrected keratinocyte autografts (13,15,17,49). None of the above are consistently efficacious, and some of them involve substantial risk and considerable invasiveness.…”

“…None of the above are consistently efficacious, and some of them involve substantial risk and considerable invasiveness. Gentamicin therapy has many advan-areas were determined with an image analyzer (AlphaEase FC version 4.1.0; Alpha Innotech) as described (8,12). Wound closure percentages were graded as follows: 85%-100% (+++); 50%-85% (++); and less than 50% (+).…”

“…Unfortunately, there are no cures or even effective treatments for RDEB. Various therapeutic strategies have been envisioned for RDEB, including recombinant type VII collagen-based protein therapy (6)(7)(8)(9)(10), bone marrow stem cells, or allogeneic dermal fibroblast-based cell therapy and transplantation of gene-corrected keratinocyte autografts (11)(12)(13)(14)(15)(16)(17). However, none of these therapies are consistently effective, and some have associated morbidity and mortality.…”

Management of chronic wounds in patients with dystrophic epidermolysis bullosa: challenges and solutions

“…Preclinical studies 72 have shown that recombinant human C7 delivered by intradermal injection is capable of migrating to the basement membrane and being incorporated into the DEJ of Col7a1 null mice, causing an improvement in the blistering phenotype for up to 2 months. Topical application of human recombinant C7 (rC7) accelerated wound healing 73 in mice, and intravenously administered rC7 homed to engrafted RDEB mouse skin and restored C7, anchoring fibrils, and epidermal-dermal adherence. 72,74 Further animal studies in inbred golden retriever dogs with mild RDEB revealed that intravenous administration of rC7 results in reduced wound erythema and blistering.…”