Developmental expression of α- and β- synuclein in the mouse retina.

The synuclein family comprises three presynaptic proteins-alpha-synuclein (α-Syn), beta-synuclein (β-Syn), and gamma-synuclein (γ-Syn)-which are crucial for synaptic transmission. Our previous studies have detailed the precise cellular and subcellular localization of α- and β-Syn in the adult mouse retina, revealing distinct expression patterns in excitatory and inhibitory synaptic elements. The balance between excitatory and inhibitory neurotransmitters in the inner plexiform layer (IPL) is critical for neural development in the mouse retina.

Integration and functionality of human iPSC-derived microglia in a chimeric mouse retinal model.

Introduction: Microglia, the resident immune cells of the central nervous system, play a pivotal role in maintaining homeostasis, responding to injury, and modulating neuroinflammation. However, the limitations of rodent models in accurately representing human microglia have posed significant challenges in the study of retinal diseases.

Methods: PLX5622 was used to eliminate endogenous microglia in mice through oral and intraperitoneal administration, followed by transplantation of human induced pluripotent stem cell-derived microglia (hiPSC-microglia, iMG) into retinal explants to create a novel ex vivo chimeric model containing xenotransplanted microglia (xMG).

Microglia heterogeneity during neuroinflammation and neurodegeneration in the mouse retina.

Microglia play important roles in maintaining homeostasis and immunoreactive defense in the central nervous system including retina. To accomplish such a wide range of functions, microglia are highly heterogeneous. Dark microglia (DM) were recently identified by electron microscopy (EM).

Preparing Retinal Organoid Samples for Transmission Electron Microscopy.

Retinal organoids (ROs) are a three-dimensional culture system mimicking human retinal features that have differentiated from induced pluripotent stem cells (iPSCs) under specific conditions. Synapse development and maturation in ROs have been studied immunocytochemically and functionally. However, the direct evidence of the synaptic contact ultrastructure is limited, containing both special ribbon synapses and conventional chemical synapses.

Retinal ganglion cell type-specific expression of synuclein family members revealed by scRNA-sequencing.

Synuclein family members (Snca, Sncb, and Scng) are expressed in the retina, but their precise locations and roles are poorly understood. We performed an extensive analysis of the single-cell transcriptome in healthy and injured retinas to investigate their expression patterns and roles. We observed the expression of all synuclein family members in retinal ganglion cells (RGCs), which remained consistent across species (human, mouse, and chicken).

Cell-specific localization of β-synuclein in the mouse retina.

β-synuclein, a member of the synuclein family, is frequently co-expressed with α-synuclein in the neural system, where it serves to inhibit abnormal aggregation of α-synuclein in neurodegenerative diseases. Beyond its role in pathological conditions, β-synuclein plays various functions independently of α-synuclein. In our investigation, we discovered a broader expression of β-synuclein in the mouse retina compared to α-synuclein.

Distribution and synaptic organization of substance P-like immunoreactive neurons in the mouse retina.

Substance P (SP), a neuroprotective peptidergic neurotransmitter, is known to have immunoreactivity (IR) localized to amacrine and/or ganglion cells in a variety of species' retinas, but it has not yet been studied in the mouse retina. Thus, we investigated the distribution and synaptic organization of SP-IR by confocal and electron microscopy immunocytochemistry in the mouse retina. SP-IR was distributed in the inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL).

Rod bipolar cells receive cone photoreceptor inputs through both invaginating synapses and flat contacts in the mouse and guinea pig retinas.

The light pathways are segregated into rod and cone pathways in which rods synapse with rod bipolar cells (RBCs), while cones contact cone bipolar cells (CBCs). However, previous studies found that cones can make synapse with RBCs (cone-RBC synapses) and rods can contact OFF CBC in primate and rabbit retinas. Recently, such cone-RBC synapses have been reported physiologically and morphologically in the mouse retina.

Expression of α-Synuclein in the mouse retina is confined to inhibitory presynaptic elements.

α-Synuclein (α-Syn) is enriched in presynaptic terminals of the central nervous system including the retina and plays a role in the synaptic vesicle cycle and synaptic transmission. Abnormal aggregation of α-Syn is considered to be the main component of the Lewy bodies that are the pathological hallmarks of Parkinson's disease. Although expression pattern of α-Syn has been described in the retinas, its precise cellular and subcellular locations are poorly understood.