Genetic address book for retinal cell types.

The mammalian brain is assembled from thousands of neuronal cell types that are organized in distinct circuits to perform behaviorally relevant computations. Transgenic mouse lines with selectively marked cell types would facilitate our ability to dissect functional components of complex circuits. We carried out a screen for cell type-specific green fluorescent protein expression in the retina using BAC transgenic mice from the GENSAT project. Among others, we identified mouse lines in which the inhibitory cell types of the night vision and directional selective circuit were selectively labeled. We quantified the stratification patterns to predict potential synaptic connectivity between marked cells of different lines and found that some of the lines enabled targeted recordings and imaging of cell types from developing or mature retinal circuits. Our results suggest the potential use of a stratification-based screening approach for characterizing neuronal circuitry in other layered brain structures, such as the neocortex

Cell types of the human retina and its organoids at single cell resolution: developmental convergence, transcriptional identity, and disease map

Organoids are stem cell-derived artificial organs that mimic aspects of organ development, function and disease. How closely cell type diversity and cell type maturation in human organoids recapitulate that of their target organ is not well understood. We performed histochemistry and sequenced the RNA of 163,971 single cells from improved human retinal organoids at different developmental stages and from donated healthy adult human retinas and choroid. Cell types in mature organoids had morphologies and transcriptomes that resembled their adult equivalents. Remarkably, organoids developed at a similar rate to the developing human retina and the transcriptome trajectory of cell types contained a progression of key developmental markers. Mapping disease-associated genes to cell types revealed cellular targets for studying disease mechanism in organoids and performing targeted repair in adult retinas

Genetically timed, activity-sensor and rainbow transsynaptic viral tools.

We developed retrograde, transsynaptic pseudorabies viruses (PRVs) with genetically encoded activity sensors that optically report the activity of connected neurons among spatially intermingled neurons in the brain. Next we engineered PRVs to express two differentially colored fluorescent proteins in a time-shifted manner to define a time period early after infection to investigate neural activity. Finally we used multiple-colored PRVs to differentiate and dissect the complex architecture of brain regions

Cell types of the human retina and its organoids at single-cell resolution: developmental convergence, transcriptomic identity, and disease map

How closely human organoids recapitulate cell-type diversity and cell-type maturation of their target organs is not well understood. We developed light-sensitive human retinal organoids with multiple nuclear and synaptic layers. We sequenced the RNA of 158,844 single cells from these organoids at seven developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable ‘developed’ state at a rate similar to human retina development in vivo and the transcriptomes of organoid cell types converged towards the transcriptomes of adult peripheral retinal cell types. The expression of disease-associated genes was significantly cell-type specific in adult retina and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in human retinas

Virus stamping for targeted single-cell infection in vitro and in vivo

ISSN:1546-1696ISSN:1087-015