Biology subjects

Nishina, P.

Publications and source records attributed to Nishina, P..

3 recordsLinked to original sources

bioRxiv2022

Single-cell RNA sequencing reveals molecular features of postnatal maturation in the murine retinal pigment epithelium

Transcriptomic analysis of the mammalian retinal pigment epithelium (RPE) aims to identify cellular networks that influence ocular development, maintenance, function, and disease. However, available evidence points to RPE cell heterogeneity in the native tissue, which adds complexity to transcriptomic analysis. Here, to assess cell heterogeneity, we performed single-cell RNA sequencing of RPE cells from two young adult male C57BL/6J mice. Following quality control to ensure robust transcript identification limited to cell singlets, we detected 13,858 transcripts among 2,667 and 2,846 RPE cells, respectively. Dimensional reduction by principal component analysis and uniform manifold approximation and projection revealed six distinct cell popu-lations. All clusters expressed transcripts typical of RPE cells; the smallest (C1, containing 1-2% of total cells) exhibited hallmarks of stem and/or progenitor cells. Placing C1-6 along a pseudotime axis suggested a relative decrease in melanogenesis and stem/progenitor gene expression, and a corresponding increase in visual cycle gene expression upon RPE maturation. K-means testing of all detected transcripts identified additional expression patterns that may advance understanding of RPE stem/pro-genitor cell maintenance and the evolution of cellular metabolic networks during development. This work provides new insights into the transcriptome of the mouse RPE and a baseline for identifying experimentally induced transcriptional changes in future studies of this tissue.

systems biology↗

bioRxiv2022

Comparative and longitudinal analysis of axial and retinal biometry in prospective models of hyperopia

Structured AbstractO_ST_ABSPurposeC_ST_ABSTo quantify changes in axial and retinal biometry in aging hyperopic mouse models. MethodsFundus photographs and ocular biometric measurements from Mfrprd6, Prss56glcr4, Adipor1tm1Dgen, C1qtnf5tm1.1(KOMP)Vlcg and Prss56em2(IMPC)J homozygotes and C57BL/6J control mice were ascertained longitudinally up to one year of age. Parameters including axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), outer nuclear layer thickness (ONLT), retinal thickness (RT), vitreous chamber depth (VCD) and posterior length (PL) were measured using Spectral Domain-Optical Coherence Tomography imaging. Mixed-model analysis of variance and factorial analysis of covariance, using body size as a covariate, followed by post-hoc analysis was performed to identify significant strain differences. ResultsStrain specific changes in axial and retinal biometry along with significant effects of age, sex and body size on AL were noted. Mfrprd6, Prss56glcr4, Adipor1tm1Dgen and Prss56em2(IMPC)J homozygotes had significantly shorter AL than controls. While a comparable decrease in PL was observed in Mfrprd6, Prss56glcr4, and Adipor1tm1Dgen homozygotes, the decrease was attributed to changes in different posterior components from each mutant. Mfrprd6 and Adipor1tm1Dgen homozygotes developed regularly sized fundus spots across the ocular globe, which differed from the large bright spots seen in aged Prss56glcr4 and Prss56em2(IMPC)J homozygotes. While ONLT of C1qtnf5tm1.1(KOMP)Vlcg mice was less than controls, AL and fundus images appeared normal. ConclusionsThis study highlights differences in contributions of ocular components to AL among hyperopic mouse models with decreased AL. Understanding the mechanisms through which these proteins function, will help to elucidate their role in controlling ocular growth.

genetics↗

bioRxiv2021

Deficiency in Lyst function leads to accumulation of secreted proteases and predisposition to mechanic stress-induced retinal detachment

Chediak-Higashi syndrome, caused by mutations in the Lysosome Trafficking Regulator (Lyst) gene, is a recessive hypopigmentation disorder characterized by albinism, neuropathies, neurodegeneration, and defective immune responses, with enlargement of lysosomes and lysosome-related organelles. Although recent studies have suggested that Lyst mutations impair the regulation of sizes of lysosome and lysosome-related organelle, the underlying pathogenic mechanism of Chediak-Higashi syndrome is still unclear. Here we show striking evidence that deficiency in LYST protein function leads to accumulation of photoreceptor outer segment phagosomes in retinal pigment epithelial cells, and reduces adhesion between photoreceptor outer segment and retinal pigment epithelial cells in a mouse model of Chediak-Higashi syndrome. In addition, we observe elevated levels of cathepsins, matrix metallopeptidase (MMP) 3 and oxidative stress markers in the retinal pigment epithelium of Lyst mutants. Previous reports showed that impaired degradation of photoreceptor outer segment phagosomes causes elevated oxidative stress, which could consequently lead to increases of cysteine cathepsins and MMPs in the extracellular matrix. Taken together, we conclude that the loss of LYST function causes accumulation of phagosomes in the retinal pigment epithelium and elevation of several extracellular matrix-remodeling proteases through oxidative stress, which may, in turn, reduce retinal adhesion. Our work reveals previously unreported pathogenic events in the retinal pigment epithelium caused by Lyst deficiency, which may place Chediak-Higashi syndrome patients at increased risk for retinal detachment. The same pathogenic events may be conserved in other professional phagocytic cells, such as macrophages in the immune system, contributing to overall Chediak-Higashi syndrome pathology.

genetics↗