Inducing Plasmacytoid Dendritic Like-Cells with Cell Reprogramming

Abstract

Direct cell reprogramming is an emergent way of understanding and controlling somatic cell fate. Our group has previously described direct reprogramming of fibroblasts to induced dendritic cells (iDCs) through overexpression of the transcription factors (TFs) PU.1, IRF8, and BATF3 (PIB), providing evidence that immunity can be induced with direct
reprogramming. In this project, we took advantage of a Clec9a-based DC-specific reporter system previously used in our lab to screen for candidate transcription factors with the potential to induce pDC fate in mouse embryonic fibroblasts. We used an IRF8-based additive screening approach to identify reporter-activating factors since this factor is highly expressed in pDCs and has been previously found to be essential for pDC development. Our results showed that IRF8, in combination with SPIB, are sufficient to induce reporter activation and surface expression of MHCII and B220 molecules. Individual addition of the transcription factors BCL11A, CBFA2T3, CREB3L2, ETS1, STAT1, TCF12, TCF4, or ZEB2 to this initial combination increased reporter activation and expression of some of the selected markers. Moreover, preliminary results indicate that induced cells from some combinations can secrete type I IFN and other pro-inflammatory cytokines upon TLR7 and TLR9 challenging, thus suggesting similar functional properties to pDCs.