Recessive dystrophic epidermolysis bullosa (RDEB) is a debilitating and ultimately lethal blistering disease caused by mutations to the Col7a1 gene. Development of novel cell therapies for the treatment of RDEB would be fostered by having immunodeficient mouse models able to accept human cell grafts; however, immunodeficient models of many genodermatoses such as RDEB are lacking. To overcome this limitation, we combined the clustered regularly interspaced short palindromic repeats and associated nuclease (CRISPR/Cas9) system with microinjection into NOD/SCID IL2r 3c null (NSG) embryos to rapidly develop an immunodeficient Col7a1 mouse model of RDEB. Through dose optimization, we achieve F0 biallelic knockout efficiencies exceeding 80%, allowing us to quickly generate large numbers of RDEB NSG mice for experimental use. Using this strategy, we clearly demonstrate important strain-specific differences in RDEB pathology that could underlie discordant results observed between independent studies and establish the utility of this system in proof-of-concept human cellular transplantation experiments. Importantly, we uncover the ability of a recently identified skin resident immunomodulatory dermal mesenchymal stem cell marked by ABCB5 to reduce RDEB pathology and markedly extend the lifespan of RDEB NSG mice via reduced skin infiltration of inflammatory myeloid derivatives.
Bibliographical noteFunding Information:
We thank Dr. George Murphy, Brigham and Women's Hospital, Harvard Medical School, for critical reading of the manuscript. This work was supported in part by NIH Grant R01EY025794 (to MHF and NYF), the Department of Veterans Affairs VA Merit Review Award VA RR&D 1I01RX000989 (to NYF), and a Harvard Stem Cell Institute Seed Grant (to MHF). JT is supported in part by NIH R01AR063070 and P01CA065493. MJO is supported by NIH 8UL1TR000114-02. BRW is supported by NIH T32HL007062.