Induced multipotency in adult keratinocytes through down-regulation of ΔNp63 or DGCR8

Abstract

The roles of microRNAs (miRNAs) and the miRNA processing machinery in the regulation of stem cell biology are not well understood. Here, we show that the p53 family member and p63 isoform, ΔNp63, is a transcriptional activator of a cofactor critical for miRNA processing (DGCR8). This regulation gives rise to a unique miRNA signature resulting in reprogramming cells to multipotency. Strikingly, ΔNp63 −/− epidermal cells display profound defects in terminal differentiation and express a subset of markers and miRNAs present in embryonic stem cells and fibroblasts induced to pluripotency using Yamanaka factors. Moreover, ΔNp63 −/− epidermal cells transduced with an inducible DGCR8 plasmid can differentiate into multiple cell fates in vitro and in vivo. We found that human primary keratinocytes depleted of ΔNp63 or DGCR8 can be reprogrammed in 6 d and express a unique miRNA and gene expression signature that is similar but not identical to human induced pluripotent stem cells. Our data reveal a role for ΔNp63 in the transcriptional regulation of DGCR8 to reprogram adult somatic cells into multipotent stem cells.

Transcription factor p63 bookmarks and regulates dynamic enhancers during epidermal differentiation

“…Our RNAPII ChIP-seq and RNA-seq data at the TP63 gene locus showed that Δ Np63 is the main isoform during keratinocyte differentiation, whereas the expression of the TAp63 isoform was not detected (Supplementary Fig S1D). These data are consistent with results from a recent RNA-seq analysis of the developing mouse epidermis [53] and from p63 isoform-specific knockout experiments that demonstrated the major functional role of ΔNp63 in the epidermis [54, 55]. These observations do not however rule out the possibility that the TAp63 isoform is expressed at an extremely low level, and the expression might be detected with deeper sequencing.…”

p53/p63/p73 in the Epidermis in Health and Disease

“…TAp63 is also expressed in response to stresses such as wound healing (Su et al 2009b). DNp63 plays a major role in mediating the effects of p63 on epidermal development, whereas TAp63 keeps stem cells within the skin in quiescence to avoid early depletion of these cells and suppresses tumorigenesis in postnatal epidermis (Su et al 2009b;Romano et al 2012;Chakravarti et al 2014).…”

“…Global effects of p63 on microRNAs are realized via direct regulation and transactivation of the Dicer promoter by TAp63 (Su et al 2010) and the DiGeorge syndrome critical region gene 8 (DGCR8) promoter by DNp63 (Chakravarti et al 2014). In addition, p63 negatively regulates expression of several microRNAs of the miR-34 family, which show reciprocal expression patterns with p63 in the epidermis (Antonini et al 2010).…”

Emerging from the shade of p53 mutants: N-terminally truncated variants of the p53 family in EMT signaling and cancer progression

“…Here, the DNp63a-DGCR8 pathway was shown to inhibit the expression of a unique miRNA signature that mediates the reprogramming of cells to multipotency and induces miRNAs that initiate terminal differentiation, including miR-205 and members of the miR-34 and miR-200 families. DNp63a, but not DNp63g, is able to transactivate the DGCR8 promoter (26).…”