Project description:All established protocols for differentiation of mouse and human pluripotent stem cells into specific neural subpopulations generate a considerable cellular heterogeneity that hampers experimental and clinical progress. In order to obtain a homogenous population of neuronal precursor cells and to streamline the differentiation of embryonic stem cells (ESCs), we assessed PSA-NCAM, a surface glycoprotein that is specifically expressed on immature neurons. We developed an optimized strategy for magnetic isolation of PSA-NCAM positive neuronal precursors from differentiated ESC cultures and characterized their neuronal differentiation potential in vitro. PSA-NCAM enrichment at an early step of neural differentiation increased the number of ES cell derived neurons and reduced cellular diversity. Gene expression analysis revealed that mainly genes involved in neuronal activity were over-represented after purification. The in vivo potential of in vitro derived PSA-NCAM+ enriched precursors was functionally characterized by grafting into the forebrain of adult mice. Analysis for several neuronal and glia markers at 10 or 40 days post graft showed a distinct differentiation pattern. While unsorted control cells gave rise to a mixed population composed of immature precursors, early postmitotic neurons or glial cells, the majority of PSA-NCAM+ enriched cells differentiated into NeuN positive neurons. Furthermore, when in contact with the rostral migratory stream, higher numbers of cells integrated into the stream and migrated towards the olfactory bulb when the PSA-NCAM enriched population was grafted. Thus, enrichment of neuronal precursors based on PSA-NCAM expression represents a general and straightforward approach to narrow cellular heterogeneity during neuronal differentiation of pluripotent cells. Two conditions (step 4, step 5), each represented by three biological replicates of control and enriched cells (Cy5); mESC was used as common reference (Cy3)
Project description:All established protocols for differentiation of mouse and human pluripotent stem cells into specific neural subpopulations generate a considerable cellular heterogeneity that hampers experimental and clinical progress. In order to obtain a homogenous population of neuronal precursor cells and to streamline the differentiation of embryonic stem cells (ESCs), we assessed PSA-NCAM, a surface glycoprotein that is specifically expressed on immature neurons. We developed an optimized strategy for magnetic isolation of PSA-NCAM positive neuronal precursors from differentiated ESC cultures and characterized their neuronal differentiation potential in vitro. PSA-NCAM enrichment at an early step of neural differentiation increased the number of ES cell derived neurons and reduced cellular diversity. Gene expression analysis revealed that mainly genes involved in neuronal activity were over-represented after purification. The in vivo potential of in vitro derived PSA-NCAM+ enriched precursors was functionally characterized by grafting into the forebrain of adult mice. Analysis for several neuronal and glia markers at 10 or 40 days post graft showed a distinct differentiation pattern. While unsorted control cells gave rise to a mixed population composed of immature precursors, early postmitotic neurons or glial cells, the majority of PSA-NCAM+ enriched cells differentiated into NeuN positive neurons. Furthermore, when in contact with the rostral migratory stream, higher numbers of cells integrated into the stream and migrated towards the olfactory bulb when the PSA-NCAM enriched population was grafted. Thus, enrichment of neuronal precursors based on PSA-NCAM expression represents a general and straightforward approach to narrow cellular heterogeneity during neuronal differentiation of pluripotent cells.
Project description:We identified APLNR as a surface marker for in vitro cardiac progenitors derived from human induced pluripotent stem cells (hiPSC). To gain further insight on the differentiation trajectory and its relevance with in vivo cardiac development, we performed polyA mRNA-sequencing on APLNR+ in vitro cardiac progenitors derived from 3 hiPSC lines at 0, 24, 48 and 72 hours post-immunomagnetic isolation. Our study revealed APLNR+ in vitro cardiac progenitors differentiate via a transient progenitor stage before further differentiation into cardiomyocytes and cardiac mesenchyme.
Project description:Human brain development is a complex process involving neural proliferation, differentiation, and migration which are directed by many essential cellular factors and drivers. Here, using the NetBID2 algorithm and developing human brain RNA sequencing(RNA-Seq) dataset, we identified synaptotagmin-like 3(SYTL3) as one of the top drivers of early human brain development. Interestingly, SYTL3 exhibited high activity but low expression in both early developmental human cortex and human embryonic stem cell(hESC)-derived neurons. Knockout of SYTL3(SYTL3 -KO) in human neurons or knockdown of Sytl3 in embryonic mouse cortex markedly promoted neuronal migration. Besides, SYTL3-KO caused an abnormal distribution of deep-layer neurons in brain organoids and reduced presynaptic neurotransmitter release in hESC-derived neurons. We further demonstrated that SYTL3-KO- accelerated neuronal migration was modulated by high expression of matrix metalloproteinases. Together, based on bioinformatics and biological experiments, we identified SYTL3 as a novel regulator of cortical neuronal migration in human and mouse developing brains.
Project description:The evolution of brain complexity correlates with an increased expression of long, non-coding (lnc) RNAs in neuronal tissues. Although prominent examples illustrate the potential of lncRNAs to scaffold and target epigenetic regulators to chromatin loci, only few cases have been described to function during neurogenesis. We present a first functional characterization of the lncRNA LINC01322, which we term RUS for ‘RNA upstream of Slitrk3’. The RUS gene is well conserved in mammals by sequence and synteny next to the neurodevelopmental gene Slitrk3. RUS is exclusively expressed in neural cells and its expression increases along with neuronal markers during neuronal differentiation of mouse embryonic cortical neural stem cells. Depletion of RUS locks neuronal precursors in an intermediate state towards neuronal differentiation, with arrested cell cycle and increased apoptosis. RUS associates with chromatin in the vicinity of genes involved in neurogenesis, most of which change their expression upon RUS depletion. The identification of a range of epigenetic regulators as specific RUS interactors suggests that the lncRNA may mediate gene activation and repression in a highly context-dependent manner.
Project description:Tumor cell heterogeneity in neuroblastoma, a pediatric cancer arising from neural crest-derived progenitor cells, poses a significant clinical challenge. In particular, unlike adrenergic (ADRN) neuroblastoma cells, mesenchymal (MES) cells are resistant to chemotherapy and retinoid therapy and thereby significantly contribute to relapses and treatment failures. Previous research suggested that overexpression or activation of miR-124, a neurogenic microRNA with tumor suppressor activity, can induce the differentiation of retinoic acid-resistant neuroblastoma cells. Leveraging our established screen for miRNA modulatory small molecules, we validated PP121, a dual inhibitor of tyrosine and phosphoinositide kinases, as a robust inducer of miR-124. A combination of PP121 and miR-132-inducing bufalin synergistically arrests proliferation, induces differentiation, and prolongs the survival of differentiated MES SK-N-AS cells for 8 weeks. RNA-seq and deconvolution analyses revealed a collapse of the ADRN core regulatory circuitry (CRC) and the emergence of novel CRCs associated with chromaffin cells and Schwann cell precursors. Using a similar protocol, we differentiated and maintained other MES neuroblastoma, as well as glioblastoma cells, over 16 weeks. In conclusion, our novel protocol suggests a promising treatment for therapy-resistant cancers of the nervous system. Moreover, these long-lived, differentiated cells provide valuable models for studying mechanisms underlying differentiation, maturation, and senescence.
Project description:Background: Glioblastoma (GBM) displays remarkable cell state plasticity, a major contributor to therapeutic resistance and tumor progression. While epigenetic mechanisms play a central role in driving this plasticity, the key regulators remain poorly understood, and developing effective therapeutic strategies targeting them has been challenging. Methods: We investigated the role of BRD2, a key regulator of NF-κB mediated mesenchymal (MES) transition, using GBM patient-derived xenograft (PDX) cell lines, CRISPR-mediated knock-in/knockout approaches, RNA-seq, and in vitro and in vivo modeling. BET inhibitors were employed to target MES gene expression and sensitize GBM to radiation therapy. Results: We found that PTEN loss induces RelA chromatin localization and acetylation-mediated recruitment of BRD2 to the MES gene promoters. BRD2 binding is essential for maintaining MES gene expression and phenotype. Genetic ablation or loss-of-function mutation of BRD2 bromodomains reverses MES transition, enhances radiation sensitivity, and improves survival in orthotopic xenograft models. Additionally, treatment with a brain-penetrant BD2-selective inhibitor suppresses the MES phenotype and increases radiation sensitivity of GBM stem cells in vitro. Conclusion: Our study identifies BRD2 as a key mediator of MES transition in GBM, with its bromodomains playing a crucial role in driving cell state plasticity. Targeting BRD2 with BD2-selective inhibitors offers a promising therapeutic strategy to overcome radiation resistance and improve outcomes for GBM patients.
Project description:To identify chromatin mechanisms of neuronal differentiation, we characterized the relationship between chromatin accessibility and gene expression in cerebellar granule neurons (CGNs) of the developing mouse. We used DNase-seq to globally map accessibility of cis-regulatory elements and RNA-seq to profile transcript abundance at key points in postnatal neuronal differentiation in vivo and in culture. We observed thousands of chromatin accessibility changes as CGNs differentiated and determined that many of these regions function as stage-specific neuronal enhancers. Motif discovery within differentially accessible chromatin regions suggested a novel role for the Zic family of transcription factors in CGN maturation, and we confirmed the association of Zic with these elements by ChIP-seq. Knockdown of Zic1 and Zic2 indicated Zic transcription factors are required to coordinate mature neuronal gene expression patterns. These data reveal chromatin dynamics at thousands of gene regulatory elements that facilitate gene expression patterns necessary for neuronal differentiation and function. Biological triplicate DNase-seq and RNA-seq samples from 3 in vivo cerebellum developmental stages (P7, P14, P60) and 3 cultured CGN stages (isolated granule neuron precursors, +3DIV, and +7DIV) obtained. Zic1 and Zic2 were separately knocked down by lentiviral shRNA in cultured CGNs followed by RNA-seq (2 biological replicates per KD and 2 controls). Zic1/2 ChIP-seq was performed with in vivo cerebellum at two developmental stages (P7 and P60) in duplicate with matching input and IgG controls.