Abstract
Purpose :
Sialidosis is an autosomal recessive hereditary disorder caused by the defect of neuraminidase 1 (neu1), which cleaves terminal sialic acid from glycoproteins and glycolipids. Sialidosis patients develop symptoms of myoclonus, cherry red spot and progressive visual loss. In this study, we investigated embryoid body(EB)- like structures in patient-derived iPS cells and induced retinal pigment epithelium (RPE)-like cells.
Methods :
iPS cells were established from patient blood mononuclear cells. In the absence of bFGF, iPS cells were cultured as aggregates, and part of the EB- like structures were observed and others were cultured on a flat surface to isolate RPE-like sheet. The autophagy-inducing ability in the patient RPE was confirmed by immunofluorescent staining and western blot analysis using anti-LC3. The number and area of LC3 puncta per cell in each observed field was calculated by Cellomics Array Scan Analyzer VTI (ThermoFisher Scientific) , and the values of 200 fields are shown.
Results :
Patient-derived EB- like structures resulted in the irregular shape and the formation of vacuoles filled with lipid droplets and cellular components such as damaged mitochondria. In patient-derived RPE-like cells, LC3 expression in starvation condition had declined 22.7% and the number and area of LC3 puncta had decreased in normal condition (53.3%, 30.1%) and in starvation condition (73.3%, 66.6%).
Conclusions :
The patient RPE-like cells showed impaired autophagy. Furthermore, we observed the characteristic failure of these cells in treatment process of the waste products in differentiation induction. It suggests that symptoms of sialidosis, including cherry-red spot, may be related to the dysfunction of the RPE.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.