Tissue Engineering for Cutaneous and Systemic Epidermolysis Bullosa Gene Therapy
Abstract
This project addresses the Peer Reviewed Medical Research Program (PRMRP) Topic Area Epidermolysis Bullosa, and the fiscal year 2022 PRMRP Strategic Goal Treatment. Specifically, this project seeks to Develop and test therapeutics…that enhance wound healing, Advance engineered tissue technology to improve wound healing and transplant outcomes, and Develop and test novel treatments, and/or improve upon existing treatments for associated diseases and conditions. Epidermolysis Bullosa (EB) is a group of genetic diseases characterized by fragile skin and blister formation. EB is relatively rare, affecting about 500,000 patients worldwide. Many of the symptoms of EB, such as painful blisters, chronic open wounds, and scarring, are similar to those caused by burns or chemical weapons. Recessive dystrophic EB (RDEB) is a severe, inherited form of EB due to mutations in Collagen VII (gene symbol COL7A1). The protein made by this gene (COL7) is produced by cells called keratinocytes in the upper skin layer, the epidermis, and cells called fibroblasts in the lower skin layer, the dermis. In normal skin, COL7 forms microscopic structures called anchoring fibrils that anchor the epidermis to the dermis. In RDEB, COL7 is missing or defective and anchoring fibrils fail to form, causing the epidermis to peel off with the slightest touch, forming painful blisters and open wounds that are prone to infection and heal with severe scarring. Because COL7 serves the same function in the oral cavity as in skin, RDEB patients exhibit blistering in the mouth and throat, making eating and drinking painful and contributing to malnutrition. Additionally, these patients are at risk for an aggressive form of skin cancer. Most RDEB patients die by age 40 due to manifestations of the disease. There is no cure for RDEB, but researchers have studied the use of ex vivo gene therapy for treatment of skin blisters in RDEB patients. In ex vivo gene therapy, the RDEB patient s skin cells are genetically modified in the lab to give them a functional COL7A1 gene, enabling them to make COL7 protein. These corrected cells can then be grafted back to the patient. One such therapy is made using genetically modified keratinocytes that are grown into sheets for grafting to the patient; although these can improve healing, the keratinocyte sheets are thin and fragile, and may not keep wounds closed long-term. Studies in Specific Aim 1 of the project will develop dermal templates that will contain rudimentary capillaries and have a 3-dimensional structure similar to healthy skin. The dermal templates are designed to be grafted together with sheets of RDEB patient keratinocytes modified to express COL7A1, to improve the long-term function of the healed skin. The dermal templates will be made with unrelated donor cells, so they can be used for any patient. It is expected that these cells will persist long enough to help with initial healing, stabilizing the modified keratinocytes, and then be slowly replaced by cells from the patient s body over time. In Specific Aim 2, we will create full-thickness (dermal + epidermal) skin replacements that can be grafted to RDEB patients to provide stable, long-term wound closure. Instead of using RDEB patient keratinocytes and fibroblasts, which may not grow well due to the patient s disease, we will make patient-specific stem cells, called induced pluripotent stem cells (iPS cells), that can be grown in large numbers in the lab and then be used to form almost any cell type in the body. In preliminary studies, we used a technique called genome editing to correct a patient s COL7A1 mutation in their iPS cells. The corrected iPS cells can be guided in the lab to turn into fibroblasts and keratinocytes, the skin s main structural cells, and endothelial cells, which line blood vessels. Studies in Aim 2 will use these corrected, iPS-derived skin cells to make full-thickness skin substitutes which will re
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2024
- Source ID
- HT94252310591
Entities
People
- Dorothy Supp
Organizations
- United States Army
- University of Cincinnati