A Robust and Highly Efficient Immune Cell Reprogramming System

Abstract

Here we describe a lineage reprogramming system consisting of a B cell line with an estradiol-inducible form of C/EBPalpha where cells can be converted into macrophage-like cells at 100% efficiency within 2 to 3 days. The reprogrammed cells are larger, contain altered organelle and cytoskeletal structures, are phagocytic, and exhibit an inflammatory response. Time-lapse experiments showed that the cells acquire a macrophage morphology and increased migratory activity as early as 10 hr. During induction, thousands of genes become up- or downregulated, including several dozen transcription and chromatin-remodeling factors. Time-limited exposure of cells to the inducer showed that the reprogrammed cells become transgene independent within 1 to 2 days. The reprogramming can be inhibited, at least partially, by perturbation experiments with B cell and macrophage transcription factors. The tightness, robustness, and speed of the system described make it a versatile tool to study biochemical and biological aspects of lineage reprogramming.

Logical modeling of lymphoid and myeloid cell specification and transdifferentiation

“…We have previously shown with our β-estradiol-inducible pre-B-cell line that a 24-h induction of C/EBPα followed by washout of the inducer was sufficient to trigger irreversible reprogramming (36). Shorter inducer exposure times led to the formation of two populations: one converting into macrophages, and the other initiating transdifferentiation but returning to a B-cell state.…”

“…S1C), whereas CD19 protein is lost only after 24 h (36). (iii) Our model also does not properly capture the fact that short C/EBPα pulses result in the loss of CD19 + cells, which are regained after Cebpa inactivation (36), suggesting that reversion of reprogramming is possible after short induction.…”

Stem cells and the evolving notion of cellular identity

“…In an effort anchored by Samantha Morris in my laboratory [24], we employed CellNet's predictive features to refine the conversion of B cells into macrophages by ectopic expression of CEBP/a [27,28] and fibroblasts into hepatocytes by enforced expression of Hnf4a and FoxA TFs [29,30]. In converted macrophages, CellNet identified the persistence of B-cell-associated TFs EBF1 and Pou2af1/OBF1, and their knock-down enhanced macrophage functionality in vitro.…”

Concise Review: Alchemy of Biology: Generating Desired Cell Types from Abundant and Accessible Cells

“…For example, TFs have been used under the control of a doxycycline-inducible promoter [29,32]. In an alternative approach, an inducible virus containing a fusion between C/EBPa and an estrogen hormonebinding domain were used to convert a B-cell line into macrophage-like cells more efficient [55]. This strategy results in establishing a reprogramming system in which the newly established cell phenotype becomes independent from the inducing agent at a certain time after induction.…”