Single-cell RNA sequencing of MNU injured mouse retina
Ontology highlight
ABSTRACT: We elucidate the role of prospero-related homeobox 1 (Prox1) in rendering the mammalian retina incompetent for MG(Muller glia cell)-derived regeneration. Prox1 accumulates in MG in the degenerating human and mouse retinas but not in those in the regenerating zebrafish retina. We investigated whether the transition of MG to proliferative MGPCs occurred in MNU-injured Prox1fg/fg;Chx10-CreERT2 mouse retinas through single-cell RNA sequencing analysis.
Project description:We further investigated injury-induced gene expression changes selectively in MG cell lineages. The tdTom-labeled MG and their descendant cells were isolated via FACS from uninjured or MNU-injured Glast-CreERT;R26tdTom/+ mouse retinas, which were infected with either AAV2-Ctrl Ab or AAV2-alpha Prox1, and mRNA expression patterns of individual cells were analyzed using SMART (Switching Mechanism At the 5' end of RNA Template) sequencing methods. We could identify a lineage flow from resting MG to RPC-like cells via activated MG, along with pseudo-time progression.
Project description:We found that the zebrafish non-coding element careg, which is induced in regenerating fins and heart, also participates in retina regeneration. Its activation persisted mostly in Müller glia from the onset to the termination of retina restoration. To assess the involvement of the careg:EGFP reporter during retina regeneration, we used a chemical injury model with MNU treatment. To identify the molecular profile of these cells, we performed a single-cell RNA sequencing (scRNA-seq) experiment of retinas dissected from adult careg:EGFP zebrafish at 3, 7, and 10 dpMNU. Our control retinas were dissected from fish at 3 days after treatment with heat-inactivated MNU
Project description:Although various mechanisms have been inferred for combinatorial actions of multiple carcinogens, these mechanisms have not been well demonstrated in experimental carcinogenesis models. We evaluated mammary carcinogenesis initiated by combined exposure to various doses of radiation and chemical carcinogens. Female rats at 7 weeks of age were M-NM-3-irradiated (0.2M-bM-^@M-^S2 Gy) and/or exposed to 1-methyl-1-nitrosourea (20 or 40 mg/kg, single intraperitoneal injection) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (40 mg/kg/day by gavage for 10 days) and were observed until 50 weeks of age. The incidence of mammary carcinoma increased steadily as a function of radiation dose in the absence of chemicals; mathematical analysis supported an additive increase when radiation was combined with a chemical carcinogen, irrespective of the chemical species and its dose. Hras mutations were characteristic of carcinomas that developed after chemical carcinogen treatments and were overrepresented in carcinomas induced by the combination of radiation and MNU (but not PhIP), indicating an interaction of radiation and MNU at the level of initiation. The expression profiles of seven classifier genes, previously shown to distinguish two classes of rat mammary carcinomas, categorized almost all examined carcinomas that developed after individual or combined treatments with radiation (1 Gy) and chemicals as belonging to a single class; more comprehensive screening using microarrays and a separate test sample set failed to identify differences in gene expression profiles among these carcinomas. These results suggest that a complex, multilevel interaction underlies the combinatorial action of radiation and chemical carcinogens in the experimental model. Mammary cancers were from untreated rats (n = 3) and rats treated with radiation (1 Gy; n = 4), MNU (40 mg/kg; H-rasM-bM-^@M-^Smutated cancers, n = 5; H-rasM-bM-^@M-^Snonmutated cancers, n = 4), PhIP (H-rasM-bM-^@M-^Smutated, n = 1; H-rasM-bM-^@M-^Snonmutated, n = 3), radiation 1 Gy plus MNU (40 mg/kg; H-rasM-bM-^@M-^Smutated, n = 5; H-rasM-bM-^@M-^Snonmutated, n = 4) and radiation 1 Gy plus PhIP (H-rasM-bM-^@M-^Snonmutated , n = 4). Normal mammary tissues were from untreated rats (n = 3).
Project description:Although various mechanisms have been inferred for combinatorial actions of multiple carcinogens, these mechanisms have not been well demonstrated in experimental carcinogenesis models. We evaluated mammary carcinogenesis initiated by combined exposure to various doses of radiation and chemical carcinogens. Female rats at 7 weeks of age were γ-irradiated (0.2–2 Gy) and/or exposed to 1-methyl-1-nitrosourea (20 or 40 mg/kg, single intraperitoneal injection) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (40 mg/kg/day by gavage for 10 days) and were observed until 50 weeks of age. The incidence of mammary carcinoma increased steadily as a function of radiation dose in the absence of chemicals; mathematical analysis supported an additive increase when radiation was combined with a chemical carcinogen, irrespective of the chemical species and its dose. Hras mutations were characteristic of carcinomas that developed after chemical carcinogen treatments and were overrepresented in carcinomas induced by the combination of radiation and MNU (but not PhIP), indicating an interaction of radiation and MNU at the level of initiation. The expression profiles of seven classifier genes, previously shown to distinguish two classes of rat mammary carcinomas, categorized almost all examined carcinomas that developed after individual or combined treatments with radiation (1 Gy) and chemicals as belonging to a single class; more comprehensive screening using microarrays and a separate test sample set failed to identify differences in gene expression profiles among these carcinomas. These results suggest that a complex, multilevel interaction underlies the combinatorial action of radiation and chemical carcinogens in the experimental model.
Project description:The mammalian central nervous system (CNS) is capable of tolerating chronic hypoxia, but cell type-specific responses to this stress have not been systematically characterized. In the Norrin-knockout (NdpKO) mouse, a model of familial exudative vitreoretinopathy (FEVR), developmental hypovascularization of the retina produces chronic hypoxia of inner nuclear layer (INL) neurons and Muller glia. We have used single-cell RNA sequencing, untargeted metabolomics, and metabolite labeling from 13C-glucose to compare wild type and NdpKO retinas. In NdpKO retinas, we observe gene expression responses consistent with hypoxia in Muller glia and retinal neurons, and we find a metabolic shift that combines reduced flux through the tricarboxylic acid cycle with increased synthesis of serine, glycine, and glutathione. We also used single-cell RNA sequencing to compare the responses of individual cell types in NdpKO retinas to those in the hypoxic cerebral cortex of mice that were housed for one week in a reduced oxygen environment (7.5% oxygen). In the hypoxic cerebral cortex, glial transcriptome responses most closely resemble the response of Muller glia in the NdpKO retina. In both retina and brain, vascular endothelial cells activate a previously dormant tip cell gene expression program, which likely underlies the adaptive neo-angiogenic response to chronic hypoxia. These analyses of retina and brain transcriptomes at single-cell resolution reveal both shared and cell-type-specific changes in gene expression in response to chronic hypoxia, implying both shared and distinct cell type-specific physiologic responses.
Project description:Post-transcriptional m6A methylation on mRNA plays a key role in neural development. Here, we specifically depleted Mettl14 (a key component of m6A complex) in retina progenitor cells by crossing Mettl14 fl/fl mice with the Chx10-Egfp/Cre mouse line and investigated Mettl14 depletion-induced m6A alteration in developing retinas using m6A-seq.
Project description:Post-transcriptional m6A methylation on mRNA plays a key role in neural development. Here, we specifically depleted Mettl14 (a key component of m6A complex) in retina progenitor cells by crossing Mettl14 fl/fl mice with the Chx10-Egfp/Cre mouse line and investigated cell type and transcriptome changes in the developing retinas using scRNA-seq.
Project description:Ciliary neurotrophic factor (CNTF) has been tested in clinical trials for human retinal degeneration due to its potent neuroprotective effects in various animal models. To decipher CNTF-triggered molecular events in the degenerating retina, high-throughput RNA sequencing analyses were performed using the Rds/Prph2 (P216L) transgenic mouse as a preclinical model for retinitis pigmentosa. Retinal transcriptome data was obtained for untreated wild type retinas, Rds retinas treated with a lentivirus expressing CNTF from postnatal day 25 to 35, and Rds retinas similarly treated with a control lentivirus expressing GFP. Comparisons of transcriptome data detect significant changes between wild type and Rds retinas. In addition, RNA-seq data reveal elevation of transcripts in the innate immune system and growth factor signaling, as well as altered neuronal transmission and metabolism in CNTF-treated Rds retinas. These results demonstrate the influence of exogenous CNTF on the retinal transcriptome landscape and illuminate likely CNTF impacts in degenerating human retinas.