Master retinal transcription factors define a subgroup-specific photoreceptor program and implicate novel dependencies in medulloblastoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE103902 | GEO | 2018/06/08
REPOSITORIES: GEO
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Project description:Cancer cells often express differentiation programs unrelated to their tissue of origin, although the contribution of these aberrant phenotypes to malignancy is poorly understood. An aggressive subgroup of medulloblastoma, a malignant pediatric brain tumor of the cerebellum, expresses a photoreceptor differentiation program normally expressed in the retina. We establish that two photoreceptor-specific transcription factors, NRL and CRX, are master regulators of this program and are required for tumor maintenance in this subgroup. Beyond photoreceptor lineage genes, we identify BCL-XL as a key transcriptional target of NRL and provide evidence substantiating anti-BCL therapy as a rational treatment opportunity for select MB patients. Our results highlight the utility of studying aberrant differentiation programs in cancer and their potential as selective therapeutic vulnerabilities.
| S-EPMC6368680 | biostudies-literature
Project description:Photoreceptor loss is a leading cause of blindness, but mechanisms underlying photoreceptor degeneration are not well understood. Treatment strategies would benefit from an improved understanding of gene-expression patterns directing photoreceptor development, as many genes are implicated in both development and degeneration. Neural retina leucine zipper (NRL) is critical for rod photoreceptor genesis and degeneration, with NRL mutations known to cause enhanced S-cone syndrome and retinitis pigmentosa. While murine Nrl loss has been characterized, studies of human NRL can identify important insights for human retinal disease. Here we utilized human organoid models of retinal development to molecularly define developmental alterations in a human model of NRL loss. Consistent with the function of NRL in rod fate specification, human retinal organoids lacking NRL develop S-opsin dominant photoreceptor populations. We report generation of two distinct S-opsin expressing populations in NRL null retinal organoids and identify MEF2C as a candidate regulator of cone development.
2020-01-15 | GSE143669 | GEO
Project description:Rod and cone photoreceptors in mammalian retina are generated from common pool(s) of neuroepithelial progenitors. NRL, CRX and NR2E3 are key transcriptional regulators that control photoreceptor differentiation. Mutations in NR2E3, a rod-specific orphan nuclear receptor, lead to loss of rods, increased density of S-cones, and supernormal S-cone-mediated vision in humans. To better understand its in vivo function, NR2E3 was expressed ectopically in the Nrl-/- retina, where post-mitotic precursors fated to be rods develop into functional S-cones similar to the human NR2E3 disease. Expression of NR2E3 in the Nrl-/- retina completely suppressed cone differentiation and resulted in morphologically rod-like photoreceptors, which were not functional. Gene profiling of FACS-purified photoreceptors confirmed the role of NR2E3 as a strong suppressor of cone genes and an activator of a subset of rod genes (including rhodopsin) in vivo. Ectopic expression of NR2E3 in cone precursors and differentiating S-cones of wild type retina also generates rod-like cells. The dual regulatory function of NR2E3 is not dependent upon the presence of NRL and/or CRX, but on the timing and level of its expression. Our studies reveal a critical role of NR2E3 in establishing functional specificity of post-mitotic photoreceptor precursors during retinal neurogenesis. Keywords: genetic modification
2006-08-18 | GSE5338 | GEO
Project description:Rod and cone photoreceptors in mammalian retina are generated from common pool(s) of neuroepithelial progenitors. NRL, CRX and NR2E3 are key transcriptional regulators that control photoreceptor differentiation. Mutations in NR2E3, a rod-specific orphan nuclear receptor, lead to loss of rods, increased density of S-cones, and supernormal S-cone-mediated vision in humans. To better understand its in vivo function, NR2E3 was expressed ectopically in the Nrl-/- retina, where post-mitotic precursors fated to be rods develop into functional S-cones similar to the human NR2E3 disease. Expression of NR2E3 in the Nrl-/- retina completely suppressed cone differentiation and resulted in morphologically rod-like photoreceptors, which were not functional. Gene profiling of FACS-purified photoreceptors confirmed the role of NR2E3 as a strong suppressor of cone genes and an activator of a subset of rod genes (including rhodopsin) in vivo. Ectopic expression of NR2E3 in cone precursors and differentiating S-cones of wild type retina also generates rod-like cells. The dual regulatory function of NR2E3 is not dependent upon the presence of NRL and/or CRX, but on the timing and level of its expression. Our studies reveal a critical role of NR2E3 in establishing functional specificity of post-mitotic photoreceptor precursors during retinal neurogenesis. Experiment Overall Design: We mated the Crx::Nr2e3/Nrlko mice with the Nrl::GFP transgenic mice, in which the expression of GFP is driven by an Nrl promoter. Mouse retinas were dissected at 4 wk. GFP+ photoreceptors were enriched by FACS (FACSAria, BD Biosciences, Franklin Lakes, NJ). RNA was extracted from 1~5x105 flow-sorted cells using Trizol (Invitrogen). Total RNA (40-60 ng) was used for linear amplification with Ovation Biotin labeling system (Nugen), and 2.75 ug of biotin-labeled fragmented cDNA was hybridized to mouse GeneChips MOE430.2.0 (Affymetrix) having 45,101 probesets (corresponding to over 39,000 transcripts, and 34,000 annotated mouse genes). Experiment Overall Design: Four independent samples were used at 4 weeks. We normalized Experiment Overall Design: Crx::Nr2e3/Nrl-ko-Gfp data along with Nrl-ko-Gfp 4 weeks samples ( 4 replicates, refer to Series submission GSE4051). The normalized data was then subjected to two stage analysis based on False Discovery Rate Confidence Interval (FDR-CI) for screening differentially expressed genes (24, 27) with a minimum fold change of 4.
2008-06-13 | E-GEOD-5338 | biostudies-arrayexpress
Project description:BackgroundMedulloblastoma (MB) is a heterogeneous disease in which neoplastic cells and associated immune cells contribute to disease progression. We aimed to determine the influence of neoplastic and immune cell diversity on MB biology in patient samples and animal models.MethodsTo better characterize cellular heterogeneity in MB we used single-cell RNA sequencing, immunohistochemistry, and deconvolution of transcriptomic data to profile neoplastic and immune populations in patient samples and animal models across childhood MB subgroups.ResultsNeoplastic cells cluster primarily according to individual sample of origin which is influenced by chromosomal copy number variance. Harmony alignment reveals novel MB subgroup/subtype-associated subpopulations that recapitulate neurodevelopmental processes, including photoreceptor and glutamatergic neuron-like cells in molecular subgroups GP3 and GP4, and a specific nodule-associated neuronally differentiated subpopulation in the sonic hedgehog subgroup. We definitively chart the spectrum of MB immune cell infiltrates, which include subpopulations that recapitulate developmentally related neuron-pruning and antigen-presenting myeloid cells. MB cellular diversity matching human samples is mirrored in subgroup-specific mouse models of MB.ConclusionsThese findings provide a clearer understanding of the diverse neoplastic and immune cell subpopulations that constitute the MB microenvironment.
| S-EPMC8804892 | biostudies-literature
Project description:NRL (Neural retina leucine zipper) is a key regulator of the fate determination and gene expression of rod photoreceptors in the retina of many vertebrates. In this study, we observed a unique retinal phenotype in the nrl knockout zebrafish model characterized by reduced rods with shortened outer segments and gradually increased green-cones in adulthood. By tracing and comparing the developmental processes of WT and nrl knockout rods, we found there might be two waves of rod genesis distinguished as nrl-dependent and independent with different starting times. To reveal the underlying cellular and molecular mechanisms, bulk and single-cell RNA-seq were performed. The changes in gene expression and cell proportion of rods and cones agreed well with our histological and immunofluorescence studies. Interestingly, we found that rods exhibited noticeable heterogeneities in the gene expression patterns, and a part of rods in nrl knockout zebrafish misexpressed the green-cone genes, reflecting a hybrid status of rod and green-cone. Furthermore, we identified mafba as a novel regulator of rod genesis, which was responsible for the development of rods in nrl knockout zebrafish. Our study will largely improve the current understanding of the developmental processes and regulatory mechanisms of rods in zebrafish and probably other species, and may facilitate future studies in the fields of retinal development and retinal degeneration.
2020-10-27 | GSE160140 | GEO
Project description:NRL (Neural retina leucine zipper) is a key regulator of the fate determination and gene expression of rod photoreceptors in the retina of many vertebrates. In this study, we observed a unique retinal phenotype in the nrl knockout zebrafish model characterized by reduced rods with shortened outer segments and gradually increased green-cones in adulthood. By tracing and comparing the developmental processes of WT and nrl knockout rods, we found there might be two waves of rod genesis distinguished as nrl-dependent and independent with different starting times. To reveal the underlying cellular and molecular mechanisms, bulk and single-cell RNA-seq were performed. The changes in gene expression and cell proportion of rods and cones agreed well with our histological and immunofluorescence studies. Interestingly, we found that rods exhibited noticeable heterogeneities in the gene expression patterns, and a part of rods in nrl knockout zebrafish misexpressed the green-cone genes, reflecting a hybrid status of rod and green-cone. Furthermore, we identified mafba as a novel regulator of rod genesis, which was responsible for the development of rods in nrl knockout zebrafish. Our study will largely improve the current understanding of the developmental processes and regulatory mechanisms of rods in zebrafish and probably other species, and may facilitate future studies in the fields of retinal development and retinal degeneration.
2020-10-27 | GSE160138 | GEO
Project description:Generation of three-dimensional (3D) organoids with optic cup like structures from pluripotent stem cells has created opportunities for investigating mammalian retinal development in vitro. However, retinal organoids in culture do not completely reflect the developmental state and in vivo architecture of the rod-dominant mouse retina. To assess rod photoreceptor differentiation in retinal organoids, we took advantage of Nrl-GFP mice that show rod-specific expression of GFP directed by the promoter of leucine zipper transcription factor NRL. Using embryonic and induced pluripotent stem cells (ESCs and iPSCs, respectively) derived from the Nrl-GFP mouse, we were successful in establishing long-term retinal organoid cultures (up to day 35) using modified culture conditions (called High Efficiency Hypoxia Induced Generation of Photoreceptors in Retinal Organoids, or HIPRO). We demonstrate efficient differentiation of pluripotent stem cells to retinal structures, with over 70% of embryoid bodies forming optic vesicles at Day (D)7, >50% producing optic cups by D10, and a majority of these surviving until at least D35. The HIPRO organoids include distinct inner retina neurons in somewhat stratified architecture and mature Müller glia spanning the entire retina. Almost 70% of the cells in retinal organoids are rod photoreceptors that exhibit elongated cilia. Transcriptome profiles of GFP+ rod photoreceptors, purified from organoids at Day 25-35, demonstrate a high correlation to gene profiles of purified rods from mouse retina at postnatal day (P) 2 to 6, indicating their early state of differentiation. Our 3D retinal organoids thus closely mimic in vivo retinogenesis and provide an efficient in vitro model to investigate photoreceptor development and modeling disease pathology.
2016-09-09 | GSE86790 | GEO
Project description:Medulloblastoma comprises four distinct molecular variants: WNT, SHH, Group 3, and Group 4. We analyzed alternative splicing usage in 14 normal cerebellar samples and 103 medulloblastomas of known subgroup. Medulloblastoma samples have a statistically significant increase in alternative splicing as compared to normal fetal cerebella (2.3-times; P < 6.47E-8). Splicing patterns are distinct and specific between molecular subgroups. Unsupervised hierarchical clustering of alternative splicing events accurately assigns medulloblastomas to their correct subgroup. Subgroup-specific splicing and alternative promoter usage was most prevalent in Group 3 (19.4%) and SHH (16.2%) medulloblastomas, while observed less frequently in WNT (3.2%), and Group 4 (9.3%) tumors. Functional annotation of alternatively spliced genes reveals overrepresentation of genes important for neuronal development. Alternative splicing events in medulloblastoma may be regulated in part by the correlative expression of antisense transcripts, suggesting a possible mechanism affecting subgroup-specific alternative splicing. Our results identify additional candidate markers for medulloblastoma subgroup affiliation, further support the existence of distinct subgroups of the disease, and demonstrate an additional level of transcriptional heterogeneity between medulloblastoma subgroups.
| S-EPMC3984840 | biostudies-literature
Project description:Medulloblastoma is a heterogeneous disease with at least four distinct molecular subgroups: wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4. Recently there has been considerable progress defining the molecular drivers and prognostic factors of each subgroup. However, this information has only rarely been used to stratify risk or impact treatment. The purpose of this work is to provide an update on current clinical trials that provide molecularly stratified treatment paradigms. A search was conducted on ClinicalTrials.gov using the following search terms: "medulloblastoma and subgroup", "medulloblastoma and SHH", "medulloblastoma and WNT", and "medulloblastoma and Non-WNT/Non-SHH". This search resulted in nine distinct clinical trials, five for newly diagnosed medulloblastoma and four for recurrent medulloblastoma. Four trials for newly diagnosed medulloblastoma had a component of craniospinal irradiation reduction for patients with WNT medulloblastoma. Molecularly stratified trials for recurrent medulloblastoma largely focus on SHH. As these trials are ongoing, there are limited data available. A trial in which newly-diagnosed WNT patients received modest chemotherapy without radiation has been closed to accrual due to several early failures. Phase II trials evaluating vismodegib for SHH medulloblastoma in children and adults have been disappointing. In conclusion, although there is an expanding array of clinical trials which incorporate molecular data in prescribing treatment for newly-diagnosed and recurrent medulloblastoma, treatments for these diseases are fairly uniform, with craniospinal radiation dose being the main variable. As the drivers of the distinct subgroups and their associated prognoses are better elucidated, future clinical trials and novel targeted agents are needed to improve outcomes and reduce toxicity where feasible.
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