Induced pluripotent stem cells from human revertant keratinocytes for the treatment of epidermolysis bullosa

Abstract

Revertant mosaicism is a naturally occurring phenomenon involving spontaneous correction of a pathogenic gene mutation in a somatic cell. It has been observed in several genetic diseases, including epidermolysis bullosa (EB), a group of inherited skin disorders characterized by blistering and scarring. Induced pluripotent stem cells (iPSCs), generated from fibroblasts or keratinocytes, have been proposed as a treatment for EB. However, this requires genome editing to correct the mutations, and, in gene therapy, efficiency of targeted gene correction and deleterious genomic modifications are still limitations of translation. We demonstrate the generation of iPSCs from revertant keratinocytes of a junctional EB patient with compound heterozygous COL17A1 mutations. These revertant iPSCs were then differentiated into naturally genetically corrected keratinocytes that expressed type XVII collagen (Col17). Gene expression profiling showed a strong correlation between gene expression in revertant iPSC-derived keratinocytes and the original revertant keratinocytes, indicating the successful differentiation of iPSCs into the keratinocyte lineage. Revertant-iPSC keratinocytes were then used to create in vitro three-dimensional skin equivalents and reconstitute human skin in vivo in mice, both of which expressed Col17 in the basal layer. Therefore, revertant keratinocytes may be a viable source of spontaneously gene-corrected cells for developing iPSC-based therapeutic approaches in EB.

Stem Cells in Wound Healing: The Future of Regenerative Medicine? A Mini-Review

“…Taking advantage of these characteristics, Itoh et al [48] generated in vitro 3-D skin equivalents composed exclusively of human iPSC-derived keratinocytes and fibroblasts. Two recent studies have further proven this concept; Sebastiano et al [49] and Umegaki-Arao et al [50] successfully used human keratinocyte-derived iPSCs to reconstitute skin in vitro for the treatment of recessive dystrophic epidermolysis bullosa. Additionally, Yang et al [51] successfully differentiated iPSCs into folliculogenic human epithelial stem cells to regenerate all components of the hair follicle.…”

Genetically corrected iPSCs as cell therapy for recessive dystrophic epidermolysis bullosa

“…In conclusion, our preclinical study, in conjunction with new evidence that genetically repaired (whether through gene therapy or "natural" genetic correction) iPSCs can be generated from the skin of EB patients (42,43), suggests that cell therapy is a translatable and viable route for iPSC-based cell therapy for RDEB. Our study shows that injection of genetically repaired iPSC-derived fibroblasts results not only in restored type VII collagen expression in a mouse model of human RDEB but also for the long term increases skin integrity against mechanical shear stress.…”

“…Because different culture conditions might overcome this arrest, our data do not preclude the utility of iPSC-derived keratinocytes in future cell therapy for EB patients. Sebastiano et al (42) and Umegaki-Arao et al (43) indeed show that keratinocytes derived from human iPSCs are a viable option for future RDEB therapy.…”

Novel and emerging therapies in the treatment of recessive dystrophic epidermolysis bullosa

“…Nevertheless a key challenge is to find methods for higher in vitro expansion of revertant keratinocytes as well as being able to more readily identify the revertant skin patches (107). One new approach has been to generate inducible pluripotent stem cells (iPSCs) from revertant keratinocytes (see gene therapy section below) (108,109), which potentially then offers copious functional cells that can be differentiated into multiple tissue lineages.…”