Histological and molecular restoration of type VII collagen in Recessive dystrophic epidermolysis bullosa mouse skin by topical injection of keratinocyte-like cells differentiated from human adipose-derived mesenchymal stromal cells

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe skin fragility disorder caused by mutations in the COL7A1 gene, which encodes type VII collagen (COL7), the main constituent of anchoring fibrils for attaching the epidermis to the dermis. Persistent skin erosions frequently result in intractable ulcers in RDEB patients. Adipose-derived mesenchymal stromal cells (AD-MSCs) are easily harvested in large quantities and have low immunogenicity. Therefore, they are suitable for clinical use, including applications involving allogeneic cell transplantation. Keratinocyte-like cells transdifferentiated from AD-MSCs (KC-AD-MSCs) express more COL7 than undifferentiated AD-MSCs and facilitate skin wound healing with less contracture. Therefore, these cells can be used for skin ulcer treatment in RDEB patients. We investigated whether KC-AD-MSCs transplantation ameliorated the RDEB phenotype severity in the grafted skin of a RDEB mouse model (col7a1-null) on the back of the immunodeficient mouse. KC-AD-MSCs were intradermally injected into the region surrounding the skin grafts, and this procedure was repeated after 7 days. After a further 7-day interval, the skin grafts were harvested. Neodeposition of COL7 and generation of anchoring fibrils at the dermal-epidermal junction were observed, although experiments were based on qualitative. KC-AD-MSCs may correct the COL7 insufficiency, repair defective/reduced anchoring fibrils, and improve skin integrity in RDEB patients. •KC-AD-MSCs are shown to be stratified and adhere each other by expressing desmosome-like structures.•KC-AD-MSCs-injected skin demonstrated predominantly suppressed blister formation.•Intradermal KC-AD-MSCs injection deposited COL7 at the dermal-epidermal junction.•KC-AD-MSCs have therapeutic potential for RDEB treatment.