Plant Homeo Domain Finger Protein 8 Regulates Mesodermal and Cardiac Differentiation of Embryonic Stem Cells Through Mediating the Histone Demethylation of pmaip1

Abstract

Histone demethylases have emerged as key regulators of biological processes. The H3K9me2 demethylase plant homeo domain finger protein 8(PHF8), for example, is involved in neuronal differentiation, but its potential function in the differentiation of embryonic stem cells (ESCs) to cardiomyocytes is poorly understood. Here, we explored the role of PHF8 during mesodermal and cardiac lineage commitment of mouse ESCs (mESCs). Using a phf8 knockout (ph8 -/Y ) model, we found that deletion of phf8 in ESCs did not affect self-renewal, proliferation or early ectodermal/endodermal differentiation, but it did promote the mesodermal lineage commitment with the enhanced cardiomyocyte differentiation. The effects were accompanied by a reduction in apoptosis through a caspase 3-independent pathway during early ESC differentiation, without significant differences between differentiating wide-type (ph8 1/Y ) and ph8 -/Y ESCs in cell cycle progression or proliferation. Functionally, PHF8 promoted the loss of a repressive mark H3K9me2 from the transcription start site of a proapoptotic gene pmaip1 and activated its transcription. Furthermore, knockdown of pmaip1 mimicked the phenotype of ph8 -/Y by showing the decreased apoptosis during early differentiation of ESCs and promoted mesodermal and cardiac commitment, while overexpression of pmaip1 or phf8 rescued the phenotype of ph8 -/Y ESCs by increasing the apoptosis and weakening the mesodermal and cardiac differentiation. These results reveal that the histone demethylase PHF8 regulates mesodermal lineage and cell fate decisions in differentiating mESCs through epigenetic control of the gene critical to programmed cell death pathways. STEM CELLS 2016;34:1527-1540 SIGNIFICANCE STATEMENTEmbryonic stem cells (ESCs) have the unique ability to differentiate into derivatives of all three germ layers both in vitro and in vivo. Thus, ESCs provide a unique model for the study of early embryonic development. We report here previously unrecognized effects of histone demethylase plant homeo domain finger protein 8 (PHF8) on mesodermal and early cardiac differentiation. This effect is resulted from the regulation of PHF8 on apoptosis through activating the transcription of pro-apoptotic gene pmaip1. These findings extend the knowledge in understanding of the epigenetic modification in apoptosis during ESC differentiation and of the link between apoptosis and cell lineage decision as well as cardiogenesis.

Phf8 histone demethylase deficiency causes cognitive impairments through the mTOR pathway

“…To model mental retardation in humans with PHF8 deficiency, we generated Phf8 knockout (KO) mice by targeting the exons 7 and 8 encoding the core region of mice PHF8. The strategy of generating KO allele was described in detail in previous work 22 . Genotyping results showed recombinase-mediated efficient deletion of exons 7 and 8 in the genome of mutant mice (Supplementary Fig.…”

Protein deubiquitinase USP7 is required for osteogenic differentiation of human adipose-derived stem cells

“…As a protein deubiquitinase that cleaves ubiquitin linkages from its substrates, USP7 functions to oppose ubiquitinations of various proteins including E3 ligases (MDM2/MDMX [ 35 ] and ICP0 [ 36 ]), chromatin associated factors (DNMT1 [ 37 ], UHRF1 [ 38 ], PHF8 [ 39 ], and Tip60 [ 40 ]), as well as tumor suppressors (p53 [ 41 ], PTEN [ 42 ], and claspin [ 43 ]). Among these targets, histone demethylase PHF8 is a critical epigenetic factor in cell fate determinations of stem cells [ 44 ]. Recently, Han’s study indicated that PHF8 triggered osteogenic differentiation of BMMSCs and facilitated bone formation and regeneration via epigenetically modulating the activity of a nuclear matrix protein, special AT-rich sequence-binding protein 2 (SATB2) [ 45 ].…”

miR-142-3p Contributes to Early Cardiac Fate Decision of Embryonic Stem Cells

“…R1 and E14 mESCs carrying a Brachyury-GFP (T-GFP) were maintained on mitomycin C-inactivated mouse embryonic fibroblast cells as described previously [5, 21]. Cardiomyocyte differentiation was initiated by a hanging-drop technique [22].…”