Project description:The goal of this study was to gain a detailed postnatal expression pattern of miRNAs involving time points and to identify miRNAs essential for retinal development in the mouse.
Project description:Background: Adult zebrafish spontaneously regenerate their retinas after damage. Although a number of genes and signaling pathways involved in regeneration have been identified, the extent of mechanisms regulating regeneration is unclear. Small non-coding RNAs, microRNAs (miRNAs), that regulate regeneration of various tissues in lower vertebrates were examined for their potential roles in regulating zebrafish retinal regeneration. Results: To investigate the requirement of miRNAs during zebrafish retinal regeneration, we knocked down the expression of the miRNA-processing enzyme Dicer in retinas prior to light-induced damage. Dicer loss significantly reduced proliferation of Müller glia-derived neuronal progenitor cells during regeneration. To identify individual miRNAs with roles in retina regeneration, we collected retinas at different stages of light damage and performed small RNA high-throughput sequencing. We identified subsets of miRNAs that were differentially expressed during active regeneration but returned to basal levels once regeneration was completed. To validate the roles of differentially expressed miRNAs, we knocked down 6 different miRNAs that were upregulated in expression during regeneration and demonstrated that they have distinct effects on neuronal progenitor cell proliferation and migration during retina regeneration. Conclusions: miRNAs are necessary for retinal regeneration. miRNA expression is dynamic during regeneration. miRNAs function during initiation and progression of retinal regeneration. Identification of miRNAs before, during and after completion of zebrafish retinal regeneration
Project description:The mature mammalian retina results from a complex series of developmental events. A lot of work now exists on the organization, function, and development of mouse retina, and the high-throughput technologies for gene expression analyses have helped us to obtain deep insight into the mechanism about the genes that control the retinal neurogenesis and vasculogenesis. MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs that inhibit protein translation through binding to target mRNAs. miRNAs have been reported to be involved in regulating multiple physiological and pathological activities, such as ontogenesis, organogenesis, immunoprotection, and tumorigenesis. To identify miRNAs that are specifically regulated in retinal development, total RNAs isolated from retinas isolated from mice in different developmental periods were used for high-throughput sequencing. The data presented here reveals the spatiotemporal miRNA expression patterns which occur during mice retina development and provides a foundation to further investigate how miRNAs contribute to retinal neurogenesis and vasculogenesis.
Project description:Background: Adult zebrafish spontaneously regenerate their retinas after damage. Although a number of genes and signaling pathways involved in regeneration have been identified, the extent of mechanisms regulating regeneration is unclear. Small non-coding RNAs, microRNAs (miRNAs), that regulate regeneration of various tissues in lower vertebrates were examined for their potential roles in regulating zebrafish retinal regeneration. Results: To investigate the requirement of miRNAs during zebrafish retinal regeneration, we knocked down the expression of the miRNA-processing enzyme Dicer in retinas prior to light-induced damage. Dicer loss significantly reduced proliferation of Müller glia-derived neuronal progenitor cells during regeneration. To identify individual miRNAs with roles in retina regeneration, we collected retinas at different stages of light damage and performed small RNA high-throughput sequencing. We identified subsets of miRNAs that were differentially expressed during active regeneration but returned to basal levels once regeneration was completed. To validate the roles of differentially expressed miRNAs, we knocked down 6 different miRNAs that were upregulated in expression during regeneration and demonstrated that they have distinct effects on neuronal progenitor cell proliferation and migration during retina regeneration. Conclusions: miRNAs are necessary for retinal regeneration. miRNA expression is dynamic during regeneration. miRNAs function during initiation and progression of retinal regeneration.
Project description:MicroRNA expression in the mouse eye.MicroRNAs (miRNAs) are key regulators of biological processes. To define miRNA function in the eye, it is essential to determine a high-resolution profile of their spatial and temporal distribution. In this report, we present the first comprehensive survey of miRNA expression in ocular tissues, using both microarray and RNA in situ hybridization (ISH) procedures. We initially determined the expression profiles of miRNAs in the retina, lens, cornea and retinal pigment epithelium of the adult mouse eye by microarray. Each tissue exhibited notably distinct miRNA enrichment patterns and cluster analysis identified groups of miRNAs that showed predominant expression in specific ocular tissues or combinations of them. Next, we performed RNA ISH for over 220 miRNAs, including those showing the highest expression levels by microarray, and generated a high-resolution expression atlas of miRNAs in the developing and adult wild-type mouse eye, which is accessible in the form of a publicly available web database. We found that 122 miRNAs displayed restricted expression domains in the eye at different developmental stages, with the majority of them expressed in one or more cell layers of the neural retina . This analysis revealed miRNAs with differential expression in ocular tissues and provided a detailed atlas of their tissue-specific distribution during development of the murine eye. The combination of the two approaches offers a valuable resource to decipher the contributions of specific miRNAs and miRNA clusters to the development of distinct ocular structures. microRNA profiling of ocular tissues from mouse. In particular we analysed the cornea, lens, Retina Pigment Epithelium (RPE) and retina and compared them against RNA extracted from the entire eye. The purpose of this experiment was to understand which microRNAs are present nd/or show differential expression in the various structures of the eye (cornea, lens, RPE, retina). The samples numbered 1 & 2 (i.e. CORNEA1, CORNEA2 etc ) are biological replicates, prepared from tissues dissecyed from different groups of wild-type animals. RNA extracted from the entire eye (EYE) served as the unique reference sample. For each tissue to be analysed we performed the following hybridizations: - 2 slides for lens (LENS1, LENS2) vs entire eye (EYE) - 2 slides for RPE (RPE1, RPE2) vs entire eye (EYE) - 2 slides for retina (RETINA1, RETINA2) vs entire eye (EYE) - 2 slides for cornea (CORNEA1, CORNEA2) vs entire eye (EYE) - 1 slide for entire eye (EYE) vs entire eye (EYE)
Project description:Recently we reported that the rat inner retina undergoes significant functional changes during maturation. Aiming to gain knowledge on additional aspects of retinal development and maturation, we used the microarray system to monitor gene expression patterns in the rat retina at ages 5, 11, and 20 weeks. The analysis revealed the expression of many well-documented retinal genes as well as a high number of nonâ??annotated genes. Quantitative realtime PCR analysis verified the microarray results in the majority of studied genes. A statistical analysis of the 4 microarray slides revealed 603 differentially expressed genes which were grouped into 6 expression clusters. A bioinformatic analysis of these clusters revealed sets of genes encoding proteins with functions that are likely to be relevant to inner retinal function (e.g. potassium, sodium, calcium, and chloride channels, synaptic vesicle transport, and axonogenesis). In addition, we performed a histological analysis of the maturing retina and studied different aspects of retinal structure. The analysis revealed a significant reduction of outer nuclear layer thickness between 11 and 19 weeks of age and a significant reduction of retinal ganglion cell number at 11 and 19 weeks comparing to 5 weeks. We identified in this study genes with differential expression pattern during retinal maturation. Some of the genes encode proteins that may be involved in the functional maturation of inner retinal cells. These data, taken together with our histological and electrophysiological data, contribute to our understanding of the developmental processes occurring in the retina of this widely-used animal model. Experiment Overall Design: Rat retinal samples at ages 5, 11, and 20 weeks were studied using 4 microarray slides in a dye-swap design: 5-11, 11-5, 5-20, and 20-5.
Project description:In the developing retina, as in many other regions of the central nervous system, multipotent neural progenitor cells undergo unidirectional changes to produce differentiated cells in a precise spatiotemporal order. Here we profile the epigenetic and transcriptional changes that occur during retinal development in mice and humans. Although some progenitor genes and cell cycle genes were epigenetically silenced during retinogenesis, the most dramatic change was derepression of cell type–specific differentiation programs. We identified developmental stage–specific superenhancers and showed that the majority of epigenetic changes during murine retinal development are conserved in the human retina. To determine how the epigenome changes during tumorigenesis and reprogramming, we performed the same integrated epigenetic analysis of murine and human retinoblastomas and iPSCs derived from murine rod photoreceptors. The retinoblastoma epigenome mapped to the developmental stage when retinal progenitors switch from a neurogenic to a terminal pattern of cell division and murine retinoblastomas initiate earlier in development than human tumors. The epigenome of retinoblastomas was far more similar to that of normal retina than was the epigenome of retinal-derived iPSCs but we were able to identify retinal specific epigenetic memory. Together, these data provide an in depth view of the dynamic epigenome during neurogenesis and how that relates to developmental tumors and epigenetic memory in iPSCs produced from neurons.
Project description:In the developing retina, as in many other regions of the central nervous system, multipotent neural progenitor cells undergo unidirectional changes to produce differentiated cells in a precise spatiotemporal order. Here we profile the epigenetic and transcriptional changes that occur during retinal development in mice and humans. Although some progenitor genes and cell cycle genes were epigenetically silenced during retinogenesis, the most dramatic change was derepression of cell type–specific differentiation programs. We identified developmental stage–specific superenhancers and showed that the majority of epigenetic changes during murine retinal development are conserved in the human retina. To determine how the epigenome changes during tumorigenesis and reprogramming, we performed the same integrated epigenetic analysis of murine and human retinoblastomas and iPSCs derived from murine rod photoreceptors. The retinoblastoma epigenome mapped to the developmental stage when retinal progenitors switch from a neurogenic to a terminal pattern of cell division and murine retinoblastomas initiate earlier in development than human tumors. The epigenome of retinoblastomas was far more similar to that of normal retina than was the epigenome of retinal-derived iPSCs but we were able to identify retinal specific epigenetic memory. Together, these data provide an in depth view of the dynamic epigenome during neurogenesis and how that relates to developmental tumors and epigenetic memory in iPSCs produced from neurons.
Project description:Control of neural organogenesis is a complex process and the epigenetic contribution is largely unknown. Here we have followed the genome-wide distribution of two important histone H3 modifications, H3K4me2 and H3K27me3 during late mouse retina development. We found that genes expressed only in mature rod photoreceptors, have a unique signature consisting of de-novo accumulation of H3K4me2 both at the transcription start site (TSS) and over the whole gene that correlates with the increase in transcription, but no accumulation of H3K27me3 at any stage. We also found that distribution of H3K4me2 and H3K27me3 on the genes widely expressed is not always associated with their transcriptional levels. Genes without H3K4me2 and H3K27me3 accumulation at any stage represent a group of transcripts never expressed in retina. The epigenetic signatures defined by H3K4me2 and H3K27me3 can distinguish cell-type specific genes from widespread transcripts and may be reflective of cell specificity during retina maturation. Examination of 2 different histone modifications during late mouse retina development.