Document Type

Article

Publication Date

3-3-2022

Publication Title

PLoS One

Keywords

JGM, Peptide Hydrolases

JAX Source

PLoS One 2022 Mar 3; 17(3):e0254469

Volume

17

Issue

3

First Page

0254469

Last Page

0254469

ISSN

1932-6203

PMID

35239671

DOI

https://doi.org/10.1371/journal.pone.0254469

Abstract

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. 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.

Comments

We thank the Sequencing, Histology and Imaging Sciences, and Multimedia Services at The Jackson Laboratory for their assistance in our studies. We also thank Ms. Melissa Berry for nomenclature review of the manuscript.

This is an open access article distributed under the terms of the Creative Commons Attribution License.

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