The temporal profile of retinal cell genesis in the marmoset monkey.

The New World marmoset monkey (Callithrix jacchus) has a relatively short gestational period compared with other primates but possesses a retina at a similar stage of maturation by birth. Previous studies have highlighted that the complex fovea of the marmoset undergoes a more rapid postnatal development in comparison with the Macaca monkey, reaching a mature stage earlier than these species. In this current study, we examined the prenatal proliferation profile of cells in the entire retina employing the thymidine analogs and also determined their phenotype by double-label immunocytochemistry using type-specific markers.

Primate short-wavelength cones share molecular markers with rods.

Macaca, Callithrix jacchus marmoset monkey, Pan troglodytes chimpanzee and human retinas were examined to define if short wavelength (S) cones share molecular markers with L&M cone or rod photoreceptors. S cones showed consistent differences in their immunohistochemical staining and expression levels compared to L&M cones for "rod" Arrestin1 (S-Antigen), "cone" Arrestin4, cone alpha transducin, and Calbindin. Our data verify a similar pattern of expression in these primate retinas and provide clues to the structural divergence of rods and S cones versus L&M cones, suggesting S cone retinal function is "intermediate" between them.

Retrograde transneuronal degeneration in the retina and lateral geniculate nucleus of the V1-lesioned marmoset monkey.

Retrograde transneuronal degeneration (RTD) of retinal ganglion cells and dorsal lateral geniculate (LGN) neurons are well described following a lesion of the primary visual cortex (V1) in both Old World monkeys and humans. Based on previous studies of New World monkeys and prosimians, it was suggested that these species displayed no RTD following a lesion of V1. In this study of the New World marmoset monkey, 1 year after a unilateral V1 lesion either in adults or at 14 days after birth, we observed ~20 % ganglion cell (GC) loss in adult but ~70 % in infants.

Histologic development of the human fovea from midgestation to maturity.

Purpose: To describe the histologic development of the human central retina from fetal week (Fwk) 22 to 13 years.

Design: Retrospective observational case series.

Methods: Retinal layers and neuronal substructures were delineated on foveal sections of fixed tissue stained in azure II-methylene blue and on frozen sections immunolabeled for cone, rod, or glial proteins.

Maturation of the human fovea: correlation of spectral-domain optical coherence tomography findings with histology.

Purpose: To correlate human foveal development visualized by spectral-domain optical coherence tomography (SDOCT) with histologic specimens.

Design: Retrospective, observational case series.

Methods: Morphology and layer thickness of retinal SDOCT images from 1 eye each of 22 premature infants, 30 term infants, 16 children, and 1 adult without macular disease were compared to light microscopic histology from comparable ages.

Foveal cone density shows a rapid postnatal maturation in the marmoset monkey.

The spatial and temporal pattern of cone packing during marmoset foveal development was explored to understand the variables involved in creating a high acuity area. Retinal ages were between fetal day (Fd) 125 and 6 years. Cone density was determined in wholemounts using a new hexagonal quantification method.

Localizations of visual cycle components in retinal pigment epithelium.

Purpose: We used immunocytochemistry and confocal microscopy to determine whether enzymes of the rod visual cycle were uniformly distributed in retinal pigment epithelium (RPE) cells. The localizations of these enzymes were compared to known localizations of retinoid-binding proteins and associated proteins.

Methods: Antibodies to proteins and enzymes associated with the rod visual cycle were used for fluorescence immunocytochemistry with frozen sections of albino mouse and rat retina.

Expression of synaptic and phototransduction markers during photoreceptor development in the marmoset monkey Callithrix jacchus.

Marmoset photoreceptor development was studied to determine the expression sequence for synaptic, opsin, and phototransduction proteins. All markers appear first in cones within the incipient foveal center or in rods at the foveal edge. Recoverin appears in cones across 70% of the retina at fetal day (Fd) 88, indicating that it is expressed shortly after photoreceptors are generated.

Human orbital sympathetic nerve pathways.

Purpose: To determine pathways of sympathetic nerves from the orbital apex to the eyelids in human cadaver tissue using immunohistochemistry.

Methods: Human cadaver orbit tissue was sectioned and immunolabeled with a monoclonal antityrosine hydroxylase antibody.

Results: In the orbital apex, the nasociliary, frontal, lacrimal, and maxillary branches of the trigeminal nerve demonstrated intense staining upon entering the orbit.

Rod photoreceptor differentiation in fetal and infant human retina.

Human rods and cones are arranged in a precise spatial mosaic that is critical for optimal functioning of the visual system. However, the molecular processes that underpin specification of cell types within the mosaic are poorly understood. The progressive differentiation of human rods was tracked from fetal week (Fwk) 9 to postnatal (P) 8 months using immunocytochemical markers of key molecules that represent rod progression from post-mitotic precursors to outer segment-bearing functional photoreceptors.

The zinc-binding domain of Nna1 is required to prevent retinal photoreceptor loss and cerebellar ataxia in Purkinje cell degeneration (pcd) mice.

The Purkinje cell degeneration (pcd) mouse undergoes retinal photoreceptor degeneration and Purkinje cell loss. Nna1 is postulated to be the causal gene for pcd. We show that a BAC containing the Nna1 gene rescues retinal photoreceptor loss and Purkinje cell degeneration, confirming that Nna1 loss-of-function is responsible for these phenotypes.

Purkinje cell axon collaterals terminate on Cat-301+ neurons in Macaca monkey cerebellum.

The monoclonal antibody Cat-301 identifies perineuronal nets around specific neuronal types, including those in the cerebellum. This report finds in adult Macaca monkey that basket cells in the deep molecular layer; granule cell layer (GCL) interneurons including Lugaro cells; large neurons in the foliar white matter (WM); and deep cerebellar nuclei (DCN) neurons contain subsets of Cat-301 positive (+) cells. Most Cat-301+ GCL interneurons are glycine+ and all are densely innervated by a meshwork of calbindin+/glutamic acid decarboxylase+ Purkinje cell collaterals and their synapses.

Expression patterns of calretinin, calbindin and parvalbumin and their colocalization in neurons during development of Macaca monkey retina.

The developmental expression of calbindin (CalB), calretinin (CaR) and parvalbumin (PV) was followed in Macaca monkey retina using single and double immunolabeling to identify which proteins provide distinctive labels for specific cell types and to clarify the role of these proteins during development. Ganglion cells (GC) expressed PV at fetal day (Fd)55 and CaR and CalB by Fd85. CaR was downregulated after birth.

Cellular debris and ROS in age-related cortical cataract are caused by inappropriate involution of the surface epithelial cells into the lens cortex.

Purpose: To quantify changes in the lens epithelial cells and underlying lens cortex responsible for age-related cortical cataract (ARCC) in the rat.

Methods: Freshly isolated lenses were stained vitally for DNA with Hoechst 33342. Reactive oxygen species (ROS) and mitochondria were visualized and quantified by dihydrorhodamine 123 (DHR).

Development of the human retina in the absence of ganglion cells.

Retinal development was studied in eyes from fetal and neonatal human anencephalic (AnC) and normal age-matched infants to determine the time of retinal ganglion cell (GC) loss and its effect on the development of other retinal neurons. At fetal week (Fwk) 14, GC loss was evident in central retina and by Fwk 19-20 almost all GC were absent, although immunocytochemical labeling for GC markers brain 3, neurofilament M and parvalbumin detected a few GC in the AnC far periphery at older ages. The inner nuclear and inner plexiform (IPL) layers showed variable amounts of thinning but all normal bipolar (BP) and horizontal cell markers were still present.

Development of the neural retina and its vasculature in the marmoset Callithrix jacchus.

The morphological sequence of retinal development in the New World marmoset monkey Callithrix jacchus is similar to previous reports in Macaca and humans. The incipient fovea is present at fetal day (Fd) 100 as the only part of the retina that contains five distinct layers, including a single layer of cone photoreceptors. A foveal pit begins to form at Fd 135 in the center of the foveal avascular zone which is surrounded by a ring of blood vessels (BV) and astrocytes.

Accumulation of DNA, nuclear and mitochondrial debris, and ROS at sites of age-related cortical cataract in mice.

Purpose: Lenses from young and old mice were analyzed by laser scanning confocal microscopy (LSCM) with vital dyes, to determine whether age-related subcapsular and cortical cataracts were linked to the failure of lens fiber cells to degrade nuclei, DNA, and mitochondria properly and whether they result in the overproduction of reactive oxygen species (ROS) at the same sites.

Results: As opposed to the clear DNA-free subcapsular and cortical areas of young adult mouse lenses, these areas in cataractous old mouse lenses were found to contain accumulations of nuclei, nuclear fragments, aggregated mitochondria, and amorphous DNA as cortical inclusions (P < 0.001 between young and old lenses).

Essential role of Ca2+-binding protein 4, a Cav1.4 channel regulator, in photoreceptor synaptic function.

CaBP1-8 are neuronal Ca(2+)-binding proteins with similarity to calmodulin (CaM). Here we show that CaBP4 is specifically expressed in photoreceptors, where it is localized to synaptic terminals. The outer plexiform layer, which contains the photoreceptor synapses with secondary neurons, was thinner in the Cabp4(-/-) mice than in control mice.

RANK, RANKL, OPG, and M-CSF expression in stromal cells during corneal wound healing.

Purpose: To examine the influx of monocytes into the cornea after epithelial scrape injury and the expression of chemokines that potentially regulate monocyte phenotype in cultured corneal fibroblasts and keratocytes in situ.

Methods: Monocytes were detected by immunocytochemistry for the monocyte-specific antigen CD11b, in unwounded and epithelial scrape-wounded mouse corneas. The receptor activator of NF-kappa B ligand (RANKL), osteoprotegerin (OPG), and monocyte chemotactic and stimulating factor (M-CSF) mRNAs were detected in cultured mouse stromal fibroblasts by RT-PCR and RNase protection assay.

Cellular retinaldehyde-binding protein interacts with ERM-binding phosphoprotein 50 in retinal pigment epithelium.

Purpose: To characterize mechanisms of apical localization of visual cycle components in retinal pigment epithelium (RPE) by the identification of cellular retinaldehyde-binding protein (CRALBP) interaction partners.

Methods: An overlay assay was used to detect interactions of CRALBP with components of RPE microsomes. Interacting proteins were identified with two-dimensional (2D)-PAGE and liquid chromatography tandem mass spectrometry (LC MS/MS).

Lecithin-retinol acyltransferase is essential for accumulation of all-trans-retinyl esters in the eye and in the liver.

Lecithin-retinol acyltransferase (LRAT), an enzyme present mainly in the retinal pigmented epithelial cells and liver, converts all-trans-retinol into all-trans-retinyl esters. In the retinal pigmented epithelium, LRAT plays a key role in the retinoid cycle, a two-cell recycling system that replenishes the 11-cis-retinal chromophore of rhodopsin and cone pigments. We disrupted mouse Lrat gene expression by targeted recombination and generated a homozygous Lrat knock-out (Lrat-/-) mouse.

Development of genetically engineered tet HPV16-E6/E7 transduced human corneal epithelial clones having tight regulation of proliferation and normal differentiation.

Lack of an optimal in vitro model of human corneal epithelial (HCE) cells is a major limitation in studying normal functions and gene regulations in HCE. Moreover, availability of a multi-layered HCE culture can reduce the usage of animals in the toxicity testing of consumer products. We have developed tetracycline-responsive human papilloma virus (HPV) 16-E6/E7 transduced HCE clones showing tight regulation of proliferation and normal differentiation.

Polyglutamine-expanded ataxin-7 promotes non-cell-autonomous purkinje cell degeneration and displays proteolytic cleavage in ataxic transgenic mice.

Spinocerebellar ataxia (SCA) type 7 is an inherited neurodegenerative disorder caused by expansion of a polyglutamine tract within the ataxin-7 protein. To determine the molecular basis of polyglutamine neurotoxicity in this and other related disorders, we produced SCA7 transgenic mice that express ataxin-7 with 24 or 92 glutamines in all neurons of the CNS, except for Purkinje cells. Transgenic mice expressing ataxin-7 with 92 glutamines (92Q) developed a dramatic neurological phenotype presenting as a gait ataxia and culminating in premature death.

Polyglutamine-expanded ataxin-7 antagonizes CRX function and induces cone-rod dystrophy in a mouse model of SCA7.

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant disorder caused by a CAG repeat expansion. To determine the mechanism of neurotoxicity, we produced transgenic mice and observed a cone-rod dystrophy. Nuclear inclusions were present, suggesting that the disease pathway involves the nucleus.

Visual cycle impairment in cellular retinaldehyde binding protein (CRALBP) knockout mice results in delayed dark adaptation.

Mutations in the human CRALBP gene cause retinal pathology and delayed dark adaptation. Biochemical studies have not identified the primary physiological function of CRALBP. To resolve this, we generated and characterized mice with a non-functional CRALBP gene (Rlbp1(-/-) mice).