A Notch-dependent transcriptional mechanism controls expression of temporal patterning factors in Drosophila medulla
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE188643 | GEO | 2022/08/10
REPOSITORIES: GEO
Similar Datasets
Project description:One of the key regulatory mechanisms of brain size and neuronal diversity is through control of NB identity via cell fate maintenance. Dedifferentiation is the reversion of differentiated cells to a stem cell like fate, whereby, the gene expression program of mature cells is altered and genes associated with multipotency are expressed. Beyond the fact that misexpression of these factors and pathways caused the formation of ectopic NBs, whether these dedifferentiated NBs faithfully produce the correct number and types of neurons or glial cells, or undergo timely terminal differentiation, has not been assessed. These characteristics are key determinants of overall CNS size and function, thus are important parameters when considering whether dedifferentiation leads to tumourigenesis or can be appropriately utilized for regenerative purposes. Appropriate terminal differentiation as well as neuronal diversity are key characteristics of NSCs, and are specified through temporal patterning of the NSCs driven by the successive expression of temporal transcription factors (tTFs). In this study, we found that ectopic NSCs induced via bHLH transcription factor Deadpan (Dpn) expression in the optic lobes of the developing Drosophila CNS fail to undergo appropriate temporal progression, where they express mid-tTF, Sloppy-paired 1 (Slp-1) at the expense of late-tTF Tailless (Tll); consequently generating an excess of Twin of eyeless (Toy) positive neurons and fewer Reversed polarity (Repo) positive glial cells. Dpn overexpression also resulted in stalled progression through the cell cycle, and a failure to undergo timely terminal differentiation. Mechanistically, DamID studies demonstrated that Dpn directly binds to both Dichaete (D), a Sox-box transcription factor known to repress Slp-1, as well as a number of cell cycle genes. Promoting cell cycle progression or overexpression of D were able to re-trigger the progression of the temporal series in dedifferentiated NBs, restoring both neuronal diversity and timely NB terminal differentiation.
2023-05-24 | GSE225409 | GEO
Project description:During development, neural stem cells are temporally patterned to sequentially generate a variety of neural types before exiting the cell cycle. Temporal patterning is well-studied in Drosophila, where neural stem cells called neuroblasts sequentially express cascades of Temporal Transcription Factors (TTFs) to control the birth-order dependent neural specification. However, currently known TTFs were mostly identified through candidate antibody screening and may not be complete. In addition, many fundamental questions remain concerning the TTF cascade initiation, progression, and termination. It is also not known why temporal progression only happens in neuroblasts but not in their differentiated progeny. In this work, we performed single-cell RNA sequencing of Drosophila medulla neuroblasts of all ages to study the temporal patterning process with single-cell resolution. Our scRNA-seq data revealed that sets of genes involved in different biological processes show high to low or low to high gradients as neuroblasts age. We also identified a list of novel TTFs, and experimentally characterized their roles in the temporal progression and neural fate specification. Our study revealed a comprehensive temporal gene network that patterns medulla neuroblasts from start to end. Furthermore, we found that the progression and termination of this temporal cascade also require transcription factors differentially expressed along the differentiation axis (neuroblasts -> -> neurons). Lola proteins function as a speed modulator of temporal progression in neuroblasts; while Nerfin-1, a factor required to suppress de-differentiation in post-mitotic neurons, acts at the final temporal stage together with the last TTF of the cascade, to promote the switch to gliogenesis and the cell cycle exit. Our comprehensive study of the medulla neuroblast temporal cascade illustrated mechanisms that might be conserved in the temporal patterning of neural stem cells.
2021-12-27 | GSE168553 | GEO
Project description:The brain consists of hundreds or thousands of different neuronal types that are generated through multiple divisions of neuronal stem cells. These stem cells have the capacity to generate different neuronal types at different stages of their development. In Drosophila, this temporal patterning is driven by the successive expression of temporal transcription factors (tTFs). While a number of tTFs are known in different animals and across various parts of the nervous system, these have been mostly identified by informed guesses and antibody availability. We used single-cell mRNA sequencing to identify the likely complete series of tTFs that specify most Drosophila medulla neurons in the optic lobe. We tested the genetic interactions among these tTFs. While we verify the general principle that tTFs regulate the progression of the series by activating the next tTFs in the series and repressing the previous ones, we also identify more complex regulations. Two of the tTFs, Eyeless and Dichaete, act as hubs integrating the input of several upstream tTFs before allowing the series to progress and in turn regulating the expression of several tTFs. Moreover, we show that tTFs not only specify neuronal identity but also control subsequent neuronal differentiation. We find that terminal differentiation genes, such as neurotransmitter-related genes, are present as transcripts, but not as proteins, in immature larval neurons days before they are being used in functioning neurons; we show that these mechanisms are conserved in humans. Our results offer a comprehensive description of a temporal series of tTFs in a neuronal system, offering mechanistic insights into the regulation of the progression of the series and the regulation of neuronal diversity. This represents a proof-of-principle for the use of single-cell mRNA sequencing for the comparison of temporal patterning across phyla that can lead to an understanding of how the human brain develops and how it has evolved.
2022-01-01 | GSE167266 | GEO
Project description:As the unique cell type in articular cartilage, chondrocyte senescence is a crucial cellular event contributing to osteoarthritis development. Here we show that clathrin-mediated endocytosis and activation of Notch signaling promotes chondrocyte senescence and osteoarthritis development, which is negatively regulated by myosin light chain 3. Myosin light chain 3 (MYL3) protein levels decline sharply in senescent chondrocytes of cartilages from model mice and osteoarthritis (OA) patients. Conditional deletion of Myl3 in chondrocytes significantly promoted, whereas intra-articular injection of adeno-associated virus overexpressing MYL3 delayed, OA progression in male mice. MYL3 deficiency led to enhanced clathrin-mediated endocytosis by promoting the interaction between myosin VI and clathrin, further inducing the internalization of Notch and resulting in activation of Notch signaling in chondrocytes. Pharmacologic blockade of clathrin-mediated endocytosis-Notch signaling prevented MYL3 loss-induced chondrocyte senescence and alleviated OA progression in mice. Our results establish a previously unknown mechanism essential for cellular senescence and provide a potential therapeutic direction for OA.
2023-09-07 | PXD044684 | Pride
Project description:Adenocarcinoma is the most common histologic subtype of lung cancer, which is the leading cause of cancer death. We and others previously identified TTF-1, a lineage-specific transcription factor required for branching morphogenesis and physiological lung functions, as a lineage-survival oncogene in lung adenocarcinoma. However, how TTF-1 mediates survival signals remains elusive. Here we show that TTF-1 induces receptor tyrosine kinase-like orphan receptor 1 (ROR1), which in turn mediates TTF-1 survival signaling in lung adenocarcinoma. Inhibition of ROR1 impaired prosurvival signaling through the PI3K-AKT pathway and induced nuclear accumulation of FOXO1. These were found to be imposed, at least in part, through PTEN inactivation via c-Src, while ROR1 was shown to physically interact with and phosphorylate c-Src. ROR1 inhibition also elicited marked p38 activation, provoking ill-balance between prosurvival and proapoptotic signaling, and consequential “oncogenic shock.” In addition, we found that ROR1 is crucially involved in EGFR- and MET-mediated prosurvival signaling. ROR1 knockdown effectively induced apoptosis in lung adenocarcinoma cell lines with acquired EGFR TKI resistance conferred by a secondary T790M EGFR mutation, or HGF-elicited MET signaling and resultant switching of the addicted receptor tyrosine kinases (RTKs). Taken together, our findings indicate that ROR1 RTK is a very promising molecular target for development of a novel therapeutic means to treat this hard-to-cure cancer. Dye-swap experiment, vector control vs. stable TTF-1 transfectant of HPL1D, immortalized human peripheral lung epithelial cell line.
2011-12-31 | E-GEOD-25830 | biostudies-arrayexpress
Project description:Breast cancer is genetically heterogeneous, and recent studies have underlined a prominent contribution of epigenetics to the development of this disease. To uncover new synthetic lethalities with known breast cancer oncogenes, we screened an epigenome-focused short hairpin RNA library on a panel of engineered breast epithelial cell lines. Here we report a selective interaction between the NOTCH1 signaling pathway and the SUMOylation cascade. Knockdown of the E2-conjugating enzyme UBC9 (UBE2I) as well as inhibition of the E1-activating complex SAE1/UBA2 using ginkgolic acid impairs the growth of NOTCH1-activated breast epithelial cells. We show that upon inhibition of SUMOylation NOTCH1-activated cells proceed slower through the cell cycle and ultimately enter apoptosis. Mechanistically, activation of NOTCH1 signaling depletes the pool of unconjugated small ubiquitin-like modifier 1 (SUMO1) and SUMO2/3 leading to increased sensitivity to perturbation of the SUMOylation cascade. Depletion of unconjugated SUMO correlates with sensitivity to inhibition of SUMOylation also in patient-derived breast cancer cell lines with constitutive NOTCH pathway activation. Our investigation suggests that SUMOylation cascade inhibitors should be further explored as targeted treatment for NOTCH-driven breast cancer. We treated MCF10A and NOTCH1 cells with either DMSO or ginkgolic acid 30 uM for 3 days. Two replicates have been analysed for each condition.
2014-11-21 | E-GEOD-61727 | biostudies-arrayexpress
Project description:Aberrant Notch signaling has been linked to many cancers including choroid plexus (CP) tumors, a group of rare and predominantly pediatric brain neoplasms. We developed animal models of CP tumors by inducing sustained expression of Notch1 that recapitulate properties of human CP tumors with aberrant NOTCH signaling. Whole transcriptome and functional analyses showed that tumor cell proliferation is associated with Sonic Hedgehog (Shh) in the tumor microenvironment. Unlike CP epithelial cells, which have multiple primary cilia, tumor cells possess a solitary primary cilium as a result of Notch-mediated suppression of multiciliate diffferentiation. A Shh-driven signaling cascade in the primary cilium occurs in tumor cells but not in epithelial cells. Lineage studies show that CP tumors arise from mono-ciliated progenitors in the roof plate characterized by elevated Notch signaling. Abnormal SHH signaling and distinct ciliogenesis are detected in human CP tumors, suggesting SHH pathway and cilia differentiation as potential therapeutic avenues.
2016-01-23 | GSE77123 | GEO
Project description:We expressed DamID and Flag-tagged versions of E(spl)HLH-m5, -m8 and Su(H), in Drosophila embryos and analyzed their DNA-binding by DamID-seq and ChIP-seq. The Notch pathway controls proliferation during development and in adulthood, and is frequently affected in many disorders. However, the genetic sensitivity and multi-layered transcriptional properties of the Notch pathway has made its molecular decoding challenging. Here, we address the complexity of Notch signaling with respect to proliferation, using the developing Drosophila CNS as model. We find that a Notch/Su(H)/E(spl)-HLH cascade specifically controls daughter, but not progenitor proliferation. Additionally, we find that different E(spl)-HLH genes are required in different neuroblast lineages. The Notch/Su(H)/E(spl)-HLH cascade alters daughter proliferation by regulating four key cell cycle factors: Cyclin E, String/Cdc25, E2f and Dacapo (mammalian p21CIP1/p27KIP1/p57Kip2). ChIP and DamID analysis of Su(H) and E(spl)-HLH indicates direct transcriptional regulation of the cell cycle genes, and of the Notch pathway itself. These results point to a multi-level signaling model, and may help shed light on the dichotomous proliferative role of Notch signaling in many other systems.
2019-09-11 | GSE137195 | GEO
Project description:Loss or damage to the mandible due to trauma, treatment of oral malignancies, and other diseases is currently treated using bone grafting techniques that suffer from numerous shortcomings and contraindications. Zebrafish naturally heal large injuries to their mandibular bone, and thus offer an opportunity to understand how to boost intrinsic healing ability. Using a novel her6:mCherry Notch reporter, we show that canonical Notch signaling is induced during the initial stages of cartilage callus formation in both mesenchymal cells and chondrocytes. We also show that modulation of Notch signaling during the initial postoperative period results in lasting changes to regenerate bone quantity one month later. Notch signaling is required for mandibular bone healing, as pharmacological inhibition of Notch signaling blocks cartilage callus formation and results in non-union. Conversely, conditional transgenic activation of Notch signaling accelerates regenerative ossification. Mechanistically, we report that postoperative Notch signaling regulates multiple phases of chondroid regeneration and patterns callus metabolic landscape. Given conserved functions of Notch signaling in bone repair across vertebrates, we propose that targeted activation of Notch signaling during the early phases of bone healing may have therapeutic value.
2022-03-07 | PXD027280 | Pride
Project description:Notch signaling is an important regulator of stem cell differentiation. All canonical Notch signaling is transmitted through the DNA-binding protein CSL and hyperactivated Notch signaling is associated with tumor development; thus it may be anticipated that CSL deficiency should reduce tumor growth. In contrast, we report that genetic removal of CSL in breast tumor cells caused accelerated growth of xenografted tumors. Loss of CSL unleashed a hypoxic response during normoxic conditions, manifested by stabilization of the HIF1± protein and acquisition of a polyploid giant-cell, cancer stem cell-like, phenotype. At the transcriptome level, loss of CSL upregulated more than 1750 genes and less than 3% of those genes were part of the Notch transcriptional signature. Collectively, this suggests that CSL exerts functions beyond serving as the central node in the Notch signaling cascade and reveals a novel role for CSL in tumorigenesis and regulation of the cellular hypoxic response. CSL +/+ and CSL -/- MDA-MB-231 were subjected to Notch activation/inhibition and xenograft experiment. Total RNA were extracted from the samples and sent to NGS. Single Cell RNA-sequencing was also performed from cells isolated from xenograft tumors.
2016-02-28 | E-GEOD-77308 | biostudies-arrayexpress