Aim: To investigate the function of Kdm2a in embryonic stem cells (ESCs). Materials & methods: Expression profile analysis after Kdm2a knockout. Analysis of Kdm2a, H3K4me3 and H3K27me3 ChIP-seq data in ESCs. qPCR analysis and ChIP-qPCR analysis of epigenetic changes after Kdm2a loss. Results: Kdm2a was dispensable for pluripotency maintenance in ESCs. Kdm2a genomic binding profile was positively correlated with that of H3K4me3, Zfx and Tet1. Kdm2a directly regulated germ cell genes in primordial germ cell-like cells. Kdm2a loss led to the reduced expression of endogenous retrovirus IAPEy and resulted in the gain of H3K36me2 and loss of H3K4me3 on IAPEy. Conclusion: Kdm2a regulates germ cell genes and endogenous retroviruses in ESCs possibly through demethylating H3K36me2 and influencing H3K4me3 deposition.

Mouse embryonic stem cells (ESCs) contain a rare cell population of “two-cell embryonic like” cells (2CLCs) that display similar features to those found in the two-cell (2C) embryo and thus represent an in vitro model for studying the progress of zygotic genome activation (ZGA). However, the positive regulator determinants of the 2CLCs’ conversion and ZGA have not been completely elucidated. Here, we identify a new regulator promoting 2CLCs and ZGA transcripts. Through a combination of overexpression (OE), knockdown (KD), together with transcriptional analysis and methylome analysis, we find that Dppa3 regulates the 2CLC-associated transcripts, DNA methylation, and 2CLC population in ESCs. The differentially methylated regions (DMRs) analysis identified 6,920 (98.2%) hypomethylated, whilst only 129 (1.8%) hypermethylated, regions in Dppa3 OE ESCs, suggesting that Dppa3 facilitates 2CLCs reprogramming. The conversion to 2CLCs by overexpression of Dppa3 is also associated with DNA damage response. Dppa3 knockdown manifest impairs transition into the 2C-like state. Global DNA methylome and chromatin state analysis of Dppa3 OE ESCs reveal that Dppa3 facilitates the chromatin configuration to 2CLCs reversion. Our finding for the first time elucidates a novel role of Dppa3 in mediating the 2CLC conversion, and suggests that Dppa3 is a new regulator for ZGA progress.

Background Mesenchymal stem cells (MSCs) have demonstrated remarkable therapeutic promise for acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS). MSC secretomes contain various immunoregulatory mediators that modulate both innate and adaptive immune responses. Priming MSCs has been widely considered to boost their therapeutic efficacy for a variety of diseases. Prostaglandin E2 (PGE2) plays a vital role in physiological processes that mediate the regeneration of injured organs. Methods This work utilized PGE2 to prime MSCs and investigated their therapeutic potential in ALI models. MSCs were obtained from human placental tissue. MSCs were transduced with firefly luciferase (Fluc)/eGFP fusion protein for real-time monitoring of MSC migration. Comprehensive genomic analyses explored the therapeutic effects and molecular mechanisms of PGE2-primed MSCs in LPS-induced ALI models. Results Our results demonstrated that PGE2-MSCs effectively ameliorated lung injury and decreased total cell numbers, neutrophils, macrophages, and protein levels in bronchoalveolar lavage fluid (BALF). Meanwhile, treating ALI mice with PGE2-MSCs dramatically reduced histopathological changes and proinflammatory cytokines while increasing anti-inflammatory cytokines. Furthermore, our findings supported that PGE2 priming improved the therapeutic efficacy of MSCs through M2 macrophage polarization. Conclusion PGE2-MSC therapy significantly reduced the severity of LPS-induced ALI in mice by modulating macrophage polarization and cytokine production. This strategy boosts the therapeutic efficacy of MSCs in cell-based ALI therapy.