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Stem Cell-based Therapies for Epidermolysis Bullosa

Completed
Project lead Prof. Dennis Roop
Organisation University of Colorado Denver
Project budget USD 621,426.00
Start date / Duration 11. Jan 2012 / 36 months
Funder(s) / Co-Funder(s) DEBRA Austria, MSAP/EBEP Recommended
Research area Cellular therapy

Project details

Short lay summary

Current therapy for EB patients is primarily limited to wound care. In an attempt to permanently treat not only lesions in the skin, but also mucosal epithelia, Dr. Tolar, a collaborator on this application, performed bone marrow (BM) transplants on RDEB patients. His initial results were remarkable, prior to transplantation, very little if any collagen type VII (C7) protein could be detected in the skin of patients enrolled in the trial. However, 180 days after receiving the transplant, high levels of C7 protein were present in biopsies of the skin of the treated patients. In addition, areas of the skin that were prone to blistering before the transplant showed significant healing. Although Dr. Tolar’s initial results were very promising, there are safety concerns with allogeneic transplants (bone marrow from another individual), such as toxicity to chemotherapy required for conditioning before transplantation, and susceptibility to infections due to the necessity for immunosuppressive therapy to prevent rejection of allogeneic transplants. In fact, 2 of the 7 RDEB children included in this initial trial died due to complications associated with allogeneic bone marrow transplants. To avoid the complications of allogeneic transplants, we are proposing to generate induced pluripotent stem cells (iPSC) from EB patients who have revertant patches of skin that have self-corrected themselves. Using the patient-specific self-corrected iPSC, we will generate keratinocytes to repair the skin by grafting, and mesenchymal stem cells to systemically repair lesions in mucosal epithelia. If these patient-specific cells are not rejected by the patient’s immune system, we will expand this approach to other EB patients who do not exhibit revertant patches and genetically correct their iPSC.

What did this project achieve?

Current therapy for EB patients is primarily limited to wound care. In an attempt to permanently treat not only lesions in the skin, but also mucosal epithelia, Dr. Tolar, a collaborator on this application, performed bone marrow (BM) transplants on RDEB patients. His initial results were remarkable, prior to transplantation, very little if any collagen type VII (C7) protein could be detected in the skin of patients enrolled in the trial. However, 180 days after receiving the transplant, high levels of C7 protein were present in biopsies of the skin of the treated patients. In addition, areas of the skin that were prone to blistering before the transplant showed significant healing. Although Dr. Tolar’s initial results were very promising, there are safety concerns with allogeneic transplants (bone marrow from another individual), such as toxicity to chemotherapy required for conditioning before transplantation, and susceptibility to infections due to the necessity for immunosuppressive therapy to prevent rejection of allogeneic transplants. To avoid the complications of allogeneic transplants, we are proposing to generate induced pluripotent stem cells (iPSC) from JEB patients who have revertant patches of skin that have self-corrected themselves. Using the patient-specific self-corrected iPSC, we will generate keratinocytes to repair the skin by grafting, and mesenchymal stem cells to systemically repair lesions in mucosal epithelia. As a result of the funding, we were able to reprogram skin keratinocytes into iPSCs using a safe clinically relevant mRNA-based approach, which has never been achieved before by any other group in the world. We have also developed a novel RNA-based reprogramming technique, which results in the highly efficient generation of integration-free clinically relevant human iPSCs from patient’s samples. The developed protocol allows for the production of iPSCs from individually plated cells in a feeder-free system, which will be applicable not only for the clinical application of iPSCs but also for comprehensive studies of reprogramming mechanisms on a single cell level. The ability to reprogram primary human keratinocytes and fibroblasts into iPSCs is an important prerequisite for the successful accomplishment of the proposed research and allows us to generate clinically safe iPSCs from revertant JEB keratinocytes. In addition, we optimized the protocol for the differentiation of human iPSCs back into a keratinocyte lineage, and we obtain preliminary data indicating that iPSC-KCs are unlikely to cause an immune rejection in recipients. Our current accomplishments confirm the feasibility of the proposed research and bring us one step closer to the development of an iPSC-based therapeutic strategy for JEB and an approval for a clinical trial.


Keywords

Roop
Stem-cell
Colorado
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