Project description:Identification of genes regulated by ATH5 in a dose-dependent manner.; Identification of retinal ganglion cells (RGC)-specific genes.
Project description:Our research focus is to study the genetic etiology and molecular mechanisms of glaucoma, a disease characterized by death of the retinal ganglion cell. The QNR/D cells, the only well validated retinal ganglion cell line, are derived from the neuroretina of quail (Coturnix coturnix japonica) embryos at 7 days gestation, and contain RGC (80%) and amacrine cell (20%) populations. With the aim of investigating the effect of candidate gene on glaucoma, the QNR/D cells were transfected in four different conditions. The RNA-Sequencing analysis on these transfected cell lines to identify the related proteins with differential expression profiles.
Project description:Cue-directed axon guidance depends partly on local translation in growth cones. Many mRNA transcripts are known to reside in developing axons yet little is known about their subcellular distribution or, specifically, which transcripts are in growth cones. Laser capture microdissection (LCM) was used to isolate the growth cones of retinal ganglion cell (RGC) axons of two vertebrate species, mouse and Xenopus, coupled with unbiased genome-wide microarray profiling. Localized mRNA from the isolated growth cones of Xenopus laevis and Mus musculus retinal ganglion cells were subjected to microarray analysis
Project description:The neuronal cell death results in neurodegenerative diseases. The extracellular environment plays a critical role in regulating cell viability. In this study, we explore how intercellular communication contributes to the survival of retinal ganglion cells (RGCs) following the optic nerve crush (ONC). By performing single-cell RNA-seq on whole retinal cells, we observed transcriptomic responses in non-RGC retinal cells to the injury, with astrocytes and Müller glia having the most interactions with RGCs. By comparing the RGC subclasses showing distinct resilience cell death, we identified top 47 interactions that are stronger in the high-survival RGCs, likely representing neuroprotective interactions. We performed functional assays on one of the receptors, Mu-opioid receptor (Oprm1). Although Oprm1 is preferentially expressed in intrinsically photosensitive retinal ganglion cells (ipRGCs), its neuroprotective effect could be transferred to multiple RGC subclasses by specific overexpressing Oprm1 in pan-RGCs. Our study provides an atlas of cell-cell interactions in both intact and post-ONC retina and an effective strategy to predict molecular mechanisms in neuroprotection, underlying the principal role played by extracellular environment in supporting neuron survival.
Project description:To investigate the role of aldose reductase (AR) inhibition using Sorbinil on retinal microglia (RMG) activation, retinal ganglion cell (RGC) survival, and axon regeneration after optic nerve trauma. We observed that AR inhibition using Sorbinil attenuates RMG activation and subsequently promotes RGC survival and delays axon degeneration one week after optic nerve crush.
Project description:We optimized a workflow combining imaging-based spatial transcriptomics (MERFISH) and immunostaining on ganglion cell layer retinal flatmounts of C57/Bl6J mice.The MERFISH data shows molecularly-defined retinal ganglion cell types types exhibited non-uniform distributions. We also analyzed local neighborhoods for each cell and registered several RGC types as enriched in the perivascular niche.
Project description:Retinal ganglion cells (RGCs) are the projection neurons that transmit visual information from the retina to the brain via the optic nerve. A substantial proportion of RGCs are eliminated by programmed cell death during development to regulate their final number, yet how cell death impacts RGC development in human retinas remains poorly understood. Here, we characterized the timing and cell-type-specificity of cell death in human fetal retinas and retinal organoids. We identified two waves of apoptosis: an early wave targeting retinal neuronal precursors and a late wave affecting RGCs and other neurons. In addition to these two waves of apoptosis, organoids displayed a distinct wave of necrosis in the innermost core region that eliminates nearly all RGCs during long-term culture. To investigate the functions of the apoptotic waves during retinal development, we differentiated BAX/BAK double mutant organoids that are deficient for apoptosis. In these mutant organoids, RGC survival was improved, RGC neurogenesis and maturation were delayed, and RGCs were lost through a compensatory increase in necrosis. Our data suggest that the waves of developmental apoptosis promote human RGC neurogenesis and maturation. Together, our results highlight the roles of cell death in human RGC development and the challenges in retinal organoid design. Overcoming these obstacles would improve the utility of retinal organoids for modeling optic neuropathies like glaucoma
Project description:The retinal ganglion cell (RGC) competence factor ATOH7 is dynamically expressed during retinal histogenesis. ATOH7 transcription is controlled by a promoter-adjacent primary enhancer and a remote shadow enhancer (SE). Deletion of the ATOH7 human SE causes non‑syndromic congenital retinal non-attachment (NCRNA) disease, characterized by optic nerve aplasia and total blindness. We used genome editing to model NCRNA in mice. Deletion of the murine SE reduces Atoh7 mRNA >5-fold, but does not recapitulate optic nerve loss; however, SEdel/KO (knockout) trans heterozygotes have thin optic nerves. By analyzing Atoh7 mRNA and protein levels, RGC development and survival, and chromatin landscape effects, we show how the SE ensures robust Atoh7 transcriptional output. Combining SE deletion, KO and wild-type alleles in a genotypic series, we determined the amount of Atoh7 needed to produce a normal complement of adult RGCs, and the secondary consequences of graded reductions in Atoh7 dosage. Together these data reveal the workings of an evolutionary fail-safe, a duplicate enhancer mechanism hard-wired in the machinery of vertebrate retinal ganglion cell genesis.