(2021). Sox2 modulation increases naïve pluripotency plasticity. Iscience,
(2021). Complex-dependent histone acetyltransferase activity of KAT8 determines its role in transcription and cellular homeostasis. Molecular cell,
(2021). Generation of locus-specific degradable tag knock-ins in mouse and human cell lines. Star protocols,
(2021). MPP8 is essential for sustaining self-renewal of ground-state pluripotent stem cells. Nature communications,
Deciphering the mechanisms that control the pluripotent ground state is key for understanding embryonic development. Nonetheless, the epigenetic regulation of ground-state mouse embryonic stem cells (mESCs) is not fully understood. Here, we identify the epigenetic protein MPP8 as being essential for ground-state pluripotency. Its depletion leads to cell cycle arrest and spontaneous differentiation. MPP8 has been suggested to repress LINE1 elements by recruiting the human silencing hub (HUSH) complex to H3K9me3-rich regions. Unexpectedly, we find that LINE1 elements are efficiently repressed by MPP8 lacking the chromodomain, while the unannotated C-terminus is essential for its function. Moreover, we show that SETDB1 recruits MPP8 to its genomic target loci, whereas transcriptional repression of LINE1 elements is maintained without retaining H3K9me3 levels. Taken together, our findings demonstrate that MPP8 protects the DNA-hypomethylated pluripotent ground state through its association with the HUSH core complex, however, independently of detectable chromatin binding and maintenance of H3K9me3..
(2020). PRMT5 Inhibition Modulates E2F1 Methylation and Gene-Regulatory Networks Leading to Therapeutic Efficacy in JAK2V617F-Mutant MPN. Cancer discovery,
We investigated the role of PRMT5 in myeloproliferative neoplasm (MPN) pathogenesis and aimed to elucidate key PRMT5 targets contributing to MPN maintenance. PRMT5 is overexpressed in primary MPN cells, and PRMT5 inhibition potently reduced MPN cell proliferation ex vivo. PRMT5 inhibition was efficacious at reversing elevated hematocrit, leukocytosis, and splenomegaly in a model of JAK2V617F+ polycythemia vera and leukocyte and platelet counts, hepatosplenomegaly, and fibrosis in the MPLW515L model of myelofibrosis. Dual targeting of JAK and PRMT5 was superior to JAK or PRMT5 inhibitor monotherapy, further decreasing elevated counts and extramedullary hematopoiesis in vivo. PRMT5 inhibition reduced expression of E2F targets and altered the methylation status of E2F1 leading to attenuated DNA damage repair, cell-cycle arrest, and increased apoptosis. Our data link PRMT5 to E2F1 regulatory function and MPN cell survival and provide a strong mechanistic rationale for clinical trials of PRMT5 inhibitors in MPN.
Expression of PRMT5 and E2F targets is increased in JAK2V617F+ MPN. Pharmacologic inhibition of PRMT5 alters the methylation status of E2F1 and shows efficacy in JAK2V617F/MPLW515L MPN models and primary samples. PRMT5 represents a potential novel therapeutic target for MPN, which is now being clinically evaluated.
This article is highlighted in the In This Issue feature, p. 1611
(2019). Distinct Molecular Trajectories Converge to Induce Naive Pluripotency. Cell stem cell,
(2019). PRMT5 methylome profiling uncovers a direct link to splicing regulation in acute myeloid leukemia. Nature structural & molecular biology,
(2019). A Functional Link between Nuclear RNA Decay and Transcriptional Control Mediated by the Polycomb Repressive Complex 2. Cell reports,
(2016). Optimizing sgRNA position markedly improves the efficiency of CRISPR/dCas9-mediated transcriptional repression. Nucleic acids research,
(2016). Continual removal of H3K9 promoter methylation by Jmjd2 demethylases is vital for
self‐renewal and early development. The embo journal,
van Oosten, A.L.
(2014). NANOG Amplifies STAT3 Activation and They Synergistically Induce the Naive Pluripotent Program. Current biology,
(2014). Citrullination regulates pluripotency and histone H1 binding to chromatin. Nature,
(2014). Do all roads lead to Oct4? The emerging concepts of induced pluripotency. Trends in cell biology,
dos Santos, R.L.
(2014). MBD3/NuRD Facilitates Induction of Pluripotency in a Context-Dependent Manner. Cell stem cell,
(2013). Tcf15 Primes Pluripotent Cells for Differentiation. Cell reports,
Le Bin Chia, G.
dos Santos, R.L.
(2013). A defined Oct4 level governs cell state transitions of pluripotency entry and differentiation into all embryonic lineages. Nature cell biology,
(2012). Histone variant macroH2A marks embryonic differentiation in vivo and acts as an epigenetic barrier to induced pluripotency. Journal of cell science,
How cell fate becomes restricted during somatic cell differentiation is a long-lasting question in biology. Epigenetic mechanisms not present in pluripotent cells and acquired during embryonic development are expected to stabilize the differentiated state of somatic cells and thereby restrict their ability to convert to another fate. The histone variant macroH2A acts as a component of an epigenetic multilayer that heritably maintains the silent X chromosome and has been shown to restrict tumor development. Here we show that macroH2A marks the differentiated cell state during mouse embryogenesis. MacroH2A.1 was found to be present at low levels upon the establishment of pluripotency in the inner cell mass and epiblast, but it was highly enriched in the trophectoderm and differentiated somatic cells later in mouse development. Chromatin immunoprecipitation revealed that macroH2A.1 is incorporated in the chromatin of regulatory regions of pluripotency genes in somatic cells such as mouse embryonic fibroblasts and adult neural stem cells, but not in embryonic stem cells. Removal of macroH2A.1, macroH2A.2 or both increased the efficiency of induced pluripotency up to 25-fold. The obtained induced pluripotent stem cells reactivated pluripotency genes, silenced retroviral transgenes and contributed to chimeras. In addition, overexpression of macroH2A isoforms prevented efficient reprogramming of epiblast stem cells to naïve pluripotency. In summary, our study identifies for the first time a link between an epigenetic mark and cell fate restriction during somatic cell differentiation, which helps to maintain cell identity and antagonizes induction of a pluripotent stem cell state..
(2011). Structural and thermodynamic features of intergenic and intronic human primary microRNAs. Molecular biology,
van Oosten, A.L.
(2011). Reprogramming capacity of Nanog is functionally conserved in vertebrates and resides in a unique homeodomain. Development,
Pluripotency is a developmental ground state that can be recreated by direct reprogramming. Establishment of pluripotency is crucially dependent on the homeodomain-containing transcription factor Nanog. Compared with other pluripotency-associated genes, however, Nanog shows relatively low sequence conservation. Here, we investigated whether Nanog orthologs have the capacity to orchestrate establishment of pluripotency in Nanog–/– somatic cells. Mammalian, avian and teleost orthologs of Nanog enabled efficient reprogramming to full pluripotency, despite sharing as little as 13% sequence identity with mouse Nanog. Nanog orthologs supported self-renewal of pluripotent cells in the absence of leukemia inhibitory factor, and directly regulated mouse Nanog target genes. Related homeodomain transcription factors showed no reprogramming activity. Nanog is distinguished by the presence of two unique residues in the DNA recognition helix of its homeodomain, and mutations in these positions impaired reprogramming. On the basis of genome analysis and homeodomain identity, we propose that Nanog is a vertebrate innovation, which shared an ancestor with the Bsx gene family prior to the vertebrate radiation. However, cephalochordate Bsx did not have the capacity to replace mouse Nanog in reprogramming. Surprisingly, the Nanog homeodomain, a short sequence that contains the only recognizable conservation between Nanog orthologs, was sufficient to induce naive pluripotency in Nanog–/– somatic cells. This shows that control of the pluripotent state resides within a unique DNA-binding domain, which appeared at least 450 million years ago in a common ancestor of vertebrates. Our results support the hypothesis that naive pluripotency is a generic feature of vertebrate development..