Editing TINF2as a therapeutic approach to restore telomere length in dyskeratosis congenita

Autor: Choo, Seunga, Lorbeer, Franziska K., Regalado, Samuel G., Short, Sarah B., Wu, Shannon, Rieser, Gabrielle, Bertuch, Alison A., Hockemeyer, Dirk
Zdroj: Blood; 20240101, Issue: Preprints
Abstrakt: Mutations in the TINF2gene, encoding the shelterin protein TIN2, cause telomere shortening and the inherited bone marrow failure syndrome dyskeratosis congenita (DC). A lack of suitable model systems limits the mechanistic understanding of telomere shortening in the stem cells and thus hinders the development of treatment options for bone marrow failure. Here, we endogenously introduced TIN2-DC mutations in human embryonic stem cells (hESCs) and human hematopoietic stem and progenitor cells (HSPCs) to dissect the disease mechanism and identified a gene editing strategy that rescued the disease phenotypes. The hESCs with the T284R disease mutation exhibited the short telomere phenotype observed in DC patients. Yet, telomeres in mutant hESCs did not trigger DNA damage responses at telomeres or show exacerbated telomere shortening when differentiated into telomerase-negative cells. Disruption of the mutant TINF2allele by introducing a frameshift mutation in exon 2 restored telomere length in stem cells and the replicative potential of differentiated cells. Similarly, we introduced TIN2-DC disease variants in human HSPCs to assess the changes in telomere length and proliferative capacity. Lastly, we showed that editing at exon 2 of TINF2that restored telomere length in hESCs could be generated in TINF2-DC patient HSPCs. Our study demonstrates a simple genetic intervention that rescues the TIN2-DC disease phenotype in stem cells and provides a versatile platform to assess the efficacy of potential therapeutic approaches in vivo.
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