Project description:Stem cells reside in specific niches providing stemness-maintaining environments. Thus, the regulated migration from these niches is associated with differentiation onset. However, mechanisms retaining stem cells in their niche remain poorly understood. Here, we show that the epigenetic regulator lysine-specific demethylase 1 (Lsd1) organises the trophoblast niche of the early mouse embryo by coordinating migration and invasion of trophoblast stem cells (TSCs). Lsd1 deficiency leads to the depletion of the stem cell pool resulting from precocious migration of TSCs. Migration is induced by premature expression of the transcription factor Ovol2 that is repressed by Lsd1 in undifferentiated wild-type TSCs. Increasing Ovol2 levels suffices to recapitulate the migration phenotype. Furthermore, Lsd1-deficient TSCs exhibit a developmental bias towards cells of the syncytiotrophoblast and impaired spongiotrophoblast and trophoblast giant cell differentiation. In summary, we describe that the epigenetic modifier Lsd1 coordinates placental development by retaining TSCs in their niche and directing trophoblast differentiation. Mouse trophoblast stem cells (TSCs) were isoloated from a single conditional Lsd1-deficient mouse (Lsd1tm1SchM-CM-<le). Deletion of Lsd1 was induced eight days before the collection of RNA by addition of 0.2 M-BM-5M 4OH-tamoxife. Cells were isolated at successive stages of differentiation for total RNA extraction and hybridization on Affymetrix microarrays. To that end, we harvested cells at three time-points: before induction of differentiation (d0), two days after induction of differentiation (d2), and four days after induction of differentiation (d4). Three replicates (1, 2, 3) for control (-) and Lsd1-deficeint (+) cells were included for each differentiation stage.
Project description:Stem cells reside in specific niches providing stemness-maintaining environments. Thus, the regulated migration from these niches is associated with differentiation onset. However, mechanisms retaining stem cells in their niche remain poorly understood. Here, we show that the epigenetic regulator lysine-specific demethylase 1 (Lsd1) organises the trophoblast niche of the early mouse embryo by coordinating migration and invasion of trophoblast stem cells (TSCs). Lsd1 deficiency leads to the depletion of the stem cell pool resulting from precocious migration of TSCs. Migration is induced by premature expression of the transcription factor Ovol2 that is repressed by Lsd1 in undifferentiated wild-type TSCs. Increasing Ovol2 levels suffices to recapitulate the migration phenotype. Furthermore, Lsd1-deficient TSCs exhibit a developmental bias towards cells of the syncytiotrophoblast and impaired spongiotrophoblast and trophoblast giant cell differentiation. In summary, we describe that the epigenetic modifier Lsd1 coordinates placental development by retaining TSCs in their niche and directing trophoblast differentiation.
Project description:Trophectoderm-specific expression of Angiomotin (AMOT) in pre-implantation embryos followed by its unique expression in the post-implantation ectoplacental cone that harbors the trophoblast stem cell niche prompted our investigation on the function of AMOT in trophoblast cells. Using the in vitro trophoblast stem cell culture model, we established differentiation dependent up-regulation of AMOT expression in trophoblast cells. To understand the function of AMOT in trophoblast cells mass spectrometry-based proteomic analysis was employed to identify the AMOT interactome within the trophoblast proteome. This approach utilized immunoprecipitation of endogenous AMOT followed by fractionation on SDS-PAGE and subsequently subjecting the tryptic digested excised gel bands to mass spectrometry.
Project description:Esrrb is a transcription factor implicated in embryonic stem (ES) cell self-renewal, yet its knockout causes intrauterine lethality due to defects in trophoblast development. Here we show that in trophoblast stem (TS) cells, Esrrb is a downstream target of fibroblast growth factor (Fgf) signalling and is critical to drive TS cell self-renewal. In contrast to its occupancy of pluripotency-associated loci in ES cells, Esrrb sustains the stemness of TS cells by direct binding and regulation of TS cell-specific transcription factors including Elf5 and Eomes. To elucidate the mechanisms whereby Esrrb controls the expression of its targets, we characterized its TS cell-specific interactome by mass spectrometry. Unlike in ES cells, Esrrb interacts in TS cells with the histone demethylase Lsd1 and with the RNA Polymerase II-associated Integrator complex. Our findings provide new insights into both, the general and context-dependent wiring of transcription factor networks in stem cells by master transcription factors.
Project description:Placental trophoblasts are key determinants of in utero development. Mouse trophoblast stem cells (mTSCs), which were first derived over a decade ago, are a powerful cell culture model for studying their self-renewal or differentiation. Our attempts to isolate an equivalent population from the trophectoderm of human blastocysts generated colonies that quickly differentiated in vitro. This finding suggested that the human placenta has another progenitor niche. Here we show that the chorion is one such site. Initially, we immunolocalized pluripotency factors and trophoblast fate determinants in the early-gestation placenta, amnion and chorion. Immunoreactive cells were numerous in the chorion. We isolated these cells and plated them in medium containing FGF and an inhibitor of activin/nodal signaling, which is required for human embryonic SC self-renewal. Colonies of polarized cells with a limited lifespan emerged. Trypsin dissociation yielded continuously self-replicating monolayers. Colonies and monolayers formed the two major human trophoblast lineages—multinucleate syncytiotrophoblasts and invasive cytotrophoblasts (CTBs). Transcriptional profiling experiments revealed the factors associated with the self-renewal or differentiation of human chorionic trophoblast progenitor cells (TBPCs). They included imprinted genes, NR2F1/2, HMGA2 and adhesion molecules that were required for TBPC differentiation. Together, the results of these experiments suggested that the chorion is one source of epithelial CTB progenitors. These findings explain why CTBs of fully formed chorionic villi have a modest mitotic index and identify the chorionic mesoderm as a niche for TBPCs that support placental growth. TBPC colonies (3 biological replicates), TPBC monolayers (2 biological replicates), CTB (3 biological replicates), hESC (3 biological replicates)
Project description:Stem cells reside in specialized niches that play a critical role in modulating their fate. Supporting cells in the niche instruct fate changes to the stem cells through epigenetic enzymes that transduce cell signaling to modify gene expression. Recent studies showed that the innate immune response to muscle injury alters the muscle stem cell (MuSC) niche, it remains unknown how MuSC adapt to the modified milieu to mediate muscle repair. Here we show that the epigenetic enzyme JMJD3 coordinates MuSC adaptation to the regenerative niche in a non-cell autonomous manner where it modifies their extracellular matrix to integrate signaling that stimulates exit of quiescence. Genomics and transcriptomics approaches identified the hyaluronic acid (HA) synthesis enzyme Has2 as a key JMJD3 target gene that allows MuSCs to integrate signals from the regenerative niche. Overall, we identified a specific role for JMJD3 in regulating the expression of genes that allow MuSCs to adapt to the modified niche of regenerating muscle. We aim to determine the differential occupancy of histone H3 lysine 4 trimethyl mark muscle satellite stem cells isolated from JMJD3scKO, UTXscKO and Wild-type mice.
Project description:Stem cells reside in specialized niches that play a critical role in modulating their fate. Supporting cells in the niche instruct fate changes to the stem cells through epigenetic enzymes that transduce cell signaling to modify gene expression. Recent studies showed that the innate immune response to muscle injury alters the muscle stem cell (MuSC) niche, it remains unknown how MuSC adapt to the modified milieu to mediate muscle repair. Here we show that the epigenetic enzyme JMJD3 coordinates MuSC adaptation to the regenerative niche in a non-cell autonomous manner where it modifies their extracellular matrix to integrate signaling that stimulates exit of quiescence. Genomics and transcriptomics approaches identified the hyaluronic acid (HA) synthesis enzyme Has2 as a key JMJD3 target gene that allows MuSCs to integrate signals from the regenerative niche. Overall, we identified a specific role for JMJD3 in regulating the expression of genes that allow MuSCs to adapt to the modified niche of regenerating muscle. We aim to determine the differential occupancy of histone H3 lysine 4 trimethyl mark muscle satellite stem cells isolated from JMJD3scKO, UTXscKO and Wild-type mice.
Project description:Stem cells reside in specialized niches that play a critical role in modulating their fate. Supporting cells in the niche instruct fate changes to the stem cells through epigenetic enzymes that transduce cell signaling to modify gene expression. Recent studies showed that the innate immune response to muscle injury alters the muscle stem cell (MuSC) niche, it remains unknown how MuSC adapt to the modified milieu to mediate muscle repair. Here we show that the epigenetic enzyme JMJD3 coordinates MuSC adaptation to the regenerative niche in a non-cell autonomous manner where it modifies their extracellular matrix to integrate signaling that stimulates exit of quiescence. Genomics and transcriptomics approaches identified the hyaluronic acid (HA) synthesis enzyme Has2 as a key JMJD3 target gene that allows MuSCs to integrate signals from the regenerative niche. Overall, we identified a specific role for JMJD3 in regulating the expression of genes that allow MuSCs to adapt to the modified niche of regenerating muscle. We aim to determine the differential occupancy of histone H3 lysine 4 trimethyl mark muscle satellite stem cells isolated from JMJD3scKO, UTXscKO and Wild-type mice.