Project description:Müller cells are the primary glia of the neural retina and play crucial roles in maintaining the structural and functional homeostasis of the retina. Müller cells also possess certain levels of retinal regeneration capacity, especially in lower vertebrates. In this study, we deep sequenced the transcriptomes and methylomes of mouse Müller cells and early retinal progenitor cells (RPCs), as well as Müller cells from injured retinas and aged retinas, which will help to reveal molecular mechanisms governing Müller cells development, physiological functions and regeneration activities.
Project description:We investigated the epigenetic plasticity of adult (postnatal day (P) 28) murine Müller glia using whole-genome bisulfite sequencing (WGBS)
Project description:Non-mammalian vertebrates have a robust ability to regenerate injured retinal neurons from Müller glia cells (MG) that activate the proneural factor Achaete-scute homolog 1 (Ascl1/Mash1) and de-differentiate into progenitors cells. In contrast, mammalian MG have a limited regenerative response and fail to upregulate Ascl1 after injury. To test whether Ascl1 could restore a neurogenic potential to mammalian MG, we over-expressed Ascl1 in dissociated mouse MG cultures and intact retinal explants. Ascl1-infected MG upregulate retinal progenitor-specific genes, while downregulating glial genes. Furthermore, Ascl1 remodeled the chromatin at its targets from a repressive to active configuration. MG-derived progenitors differentiated into cells that exhibited neuronal morphologies, expressed retinal subtype-specific neuronal markers, and displayed neuron-like physiological responses. These results indicate that a single transcription factor, Ascl1, can produce a neurogenic state in mature Muller glia. Expresssion profiling was used to determine the genes that were changed after Ascl1 infection of P12 cultured Müller glia compared with those present in P0 progenitors and P7-P21 Müller glia Retinas were dissociated and FAC-sorted from Hes5-GFP mice at P0, P7, P10, P14 or P21 and submitted for profiling. WT Retinas were dissociated at P12, grown for 1 week in culture, and infected with lentiviruses expressing Ascl1 or GFP for four days. Total RNA was extracted and submitted for profiling.
Project description:In order to identify the miRNAs in adult light damaged Muller glia of the the neural retina, we isolated the Müller glia from Rlbp-CreER: Stopf/f-tdTomato by means of fluorescent activated cell sorting and analyzed their miRNAs using NanoStrings Technologies®. We compared the data to that from and Dicer1-CKO Müller glia and wild type glia Müller glia (GSE103098). We found three miRNAs potentially regulating genes involved in stress response in both data sets.
Project description:To study molecular changes during differentiation of retinal progenitor cells (RPCs) into Müller glia, we isolated Notch1+ cells (Notch1 is a marker of RPCs) from postnatal-day (P) 0, 3, 7, and 14 retinas,as well as Glast + cells (Glast/Slc1a3 is a marker of Müller glia precursors and Müller glia in the retina) from P7, P14, P21, and P28 retinas. We studied gene expression in these cells using MEEBO microarrays.
Project description:Non-mammalian vertebrates have a robust ability to regenerate injured retinal neurons from Müller glia cells (MG) that activate the proneural factor Achaete-scute homolog 1 (Ascl1/Mash1) and de-differentiate into progenitors cells. In contrast, mammalian MG have a limited regenerative response and fail to upregulate Ascl1 after injury. To test whether Ascl1 could restore a neurogenic potential to mammalian MG, we over-expressed Ascl1 in dissociated mouse MG cultures and intact retinal explants. Ascl1-infected MG upregulate retinal progenitor-specific genes, while downregulating glial genes. Furthermore, Ascl1 remodeled the chromatin at its targets from a repressive to active configuration. MG-derived progenitors differentiated into cells that exhibited neuronal morphologies, expressed retinal subtype-specific neuronal markers, and displayed neuron-like physiological responses. These results indicate that a single transcription factor, Ascl1, can produce a neurogenic state in mature Muller glia. Expresssion profiling was used to determine the genes that were changed after Ascl1 infection of P12 cultured Müller glia compared with those present in P0 progenitors and P7-P21 Müller glia
Project description:Loss of neurons in the neural retina is a leading cause of vision loss. Retinal regeneration in zebrafish is attributed to Müller glia, which are activated, adopt a stem cell-like state, proliferate, and generate new neurons. Despite the same endogenous Müller glia being present in all vertebrates including humans, Müller glia activation in mammals leads to glial scarring instead of neurogenesis. Therefore, understanding Müller glia cellular states and molecular processes during zebrafish regeneration may allow us to improve mammalian regeneration. Since only a subset of Müller glia activate following neuron loss, we asked whether a specialised subset of Müller glia might be genetically primed for activation. Single-cell RNA sequencing (sc-RNAseq) from integrated zebrafish Müller glia samples reveals heterogeneity of gene expression across the quiescent Müller glia pool with 4 main clusters emerging, two of which are genetically similar. Labelling for key differentially expressed markers identified that these main clusters correlated with glia spatially distributed across dorsal, central and ventral retina. Using a genetically driven, chemically induced nitroreductase approach, three distinct photoreceptor types were ablated: the long (Lws2), short wavelength-sensitive (Sws2) and rod (Xops) photoreceptors, which also differ in their abundance. As expected, histological analysis of the three injuries and sc-RNAseq data for the two cone photoreceptor ablations identified common genetic program involved in the transition of Müller glia quiescence to activation, and differential responses to injury related to either injury extent or subtype of photoreceptor targeted. Interestingly, despite differences in the distributed across the retina, biased activation of Müller glia was observed in dorsal and central regions. Gene ontology analysis revealed that these injury-responsive dorsal and central Müller glia express genes related to dorsal/ventral pattern formation, growth factor activity, and regulation of developmental process. Müller glia upregulated genes related to homeostasis as well as certain AP-1 and injury-responsive transcription factors, followed by expression of genes involved in cell cycle, chromatin remodeling, and microtubule organisation. Prior to cell cycle entry, Müller glia show a transient upregulation of genes involved in gliogenesis, and Notch signalling. These findings enhance our understanding of heterogeneous states of quiescent Müller glia, and how these differences relate to activation and regeneration potential following neural ablation. A comparison of the distinct quiescent Müller glia with glia states in mammals will reveal key molecular pathways that could be targeted for improved mammalian neural regeneration.
Project description:Müller glia can serve as a source for retinal regeneration in some non-mammalian vertebrates. Recently we found that this process can be induced in mouse Müller glia after injury, by combining transgenic expression of the proneural transcription factor Ascl1 and the HDAC inhibitor TSA. However, new neurons are only generated from a subset of Müller glia in this model, and identifying factors that limit Ascl1-mediated MG reprogramming could potentially make this process more efficient, and potentially useful clinically. One factor that limits neurogenesis in some non-mammalian vertebrates is the STAT pathway activation that occurs in Müller glia in response to injury. In this report, we tested whether injury induced STAT activation hampers the ability of Ascl1 to reprogram Müller glia into retinal neurons. Using a STAT inhibitor, in combination with our previously described reprogramming paradigm, we found a large increase in the ability of Müller glia to generate neurons, similar to those we described previously. Single-cell RNA-seq showed that the progenitor-like cells derived from Ascl1-expressing Müller glia have a higher level of STAT signaling than those that become neurons. Using Ascl1 ChIP-seq and DNase-seq, we found that developmentally inappropriate Ascl1 binding sites (that were unique to the overexpression context) had enrichment for the STAT binding motif. This study provides evidence that STAT pathway activation reduces the efficiency of Ascl1-mediated reprogramming in Müller glia, potentially by directing Ascl1 to developmentally inappropriate targets.