D. Agudelo et al. (JUN 2017)
Nature methods 14 6 615--620
Marker-free coselection for CRISPR-driven genome editing in human cells.
Targeted genome editing enables the creation of bona fide cellular models for biological research and may be applied to human cell-based therapies. Therefore, broadly applicable and versatile methods for increasing its efficacy in cell populations are highly desirable. We designed a simple and robust coselection strategy for enrichment of cells with either nuclease-driven nonhomologous end joining (NHEJ) or homology-directed repair (HDR) events by harnessing the multiplexing capabilities of CRISPR-Cas9 and Cpf1 systems. Selection for dominant alleles of the ubiquitous sodium/potassium pump (Na+/K+ ATPase) that rendered cells resistant to ouabain was used to enrich for custom genetic modifications at another unlinked locus of interest, thereby effectively increasing the recovery of engineered cells. The process is readily adaptable to transformed and primary cells, including hematopoietic stem and progenitor cells. The use of universal CRISPR reagents and a commercially available small-molecule inhibitor streamlines the incorporation of marker-free genetic changes in human cells.
TPO, Human, Recombinant
StemSpan™ CD34+ Expansion Supplement (10X)
EasySep™ Human CD34 Positive Selection Kit
Wu X et al. (JAN 2018)
Cell 172 3 423--438.e25
Intrinsic Immunity Shapes Viral Resistance of Stem Cells.
Stem cells are highly resistant to viral infection compared to their differentiated progeny; however, the mechanism is mysterious. Here, we analyzed gene expression in mammalian stem cells and cells at various stages of differentiation. We find that, conserved across species, stem cells express a subset of genes previously classified as interferon (IFN) stimulated genes (ISGs) but that expression is intrinsic, as stem cells are refractory to interferon. This intrinsic ISG expression varies in a cell-type-specific manner, and many ISGs decrease upon differentiation, at which time cells become IFN responsive, allowing induction of a broad spectrum of ISGs by IFN signaling. Importantly, we show that intrinsically expressed ISGs protect stem cells against viral infection. We demonstrate the in vivo importance of intrinsic ISG expression for protecting stem cells and their differentiation potential during viral infection. These findings have intriguing implications for understanding stem cell biology and the evolution of pathogen resistance.