Ribosome biogenesis and hematopoiesis are impaired in induced pluripotent stem cells (iPSCs) from Diamond Blackfan anemia (DBA) patients.
The abnormalities of DBA iPSCs are ameliorated by genetic restoration of the defective ribosomal protein genes.
Diamond Blackfan anemia (DBA) is a congenital disorder with erythroid hypoplasia and tissue morphogenic abnormalities. Most DBA cases are caused by heterozygous null mutations in genes encoding ribosomal proteins. Understanding how haploinsufficiency of these ubiquitous proteins causes DBA is hampered by limited availability of tissues from affected patients. We generated induced pluripotent stem cells (iPSCs) from fibroblasts of DBA patients carrying mutations in RPS19 and RPL5. Compared to controls, DBA fibroblasts formed iPSCs inefficiently, although we obtained one stable clone from each fibroblast line. RPS19-mutated iPSCs exhibited defects in 40S (small) ribosomal subunit assembly and production of 18S rRNA. Upon induced differentiation, the mutant clone exhibited globally impaired hematopoiesis, with the erythroid lineage affected most profoundly. RPL5 haploinsufficient iPSCs exhibited defective 60S (large) ribosomal subunit assembly, accumulation of 12S pre-rRNA and impaired erythropoiesis. In both mutant iPSC lines, genetic correction of ribosomal protein deficiency via cDNA transfer into the "safe harbor" AAVS1 locus alleviated abnormalities in ribosome biogenesis and hematopoiesis. Our studies show that pathological features of DBA are recapitulated by iPSCs, provide a renewable source of cells to model various tissue defects and demonstrate proof of principle for genetic correction strategies in patient stem cells.
- Submitted January 15, 2013.
- Accepted May 28, 2013.
- Copyright © 2005 American Society of Hematology