Alteration of exosomes secreted from renal tubular epithelial cells exposed to high-concentration oxalate.

Ziqi He,Xiaofeng Guan,Jihua Wu,Yaoliang Deng,Yunlong Liu,Zhiwei Tao,Quan Liu

doi:10.18632/oncotarget.21517

Ziqi He, Xiaofeng Guan + Show 5 more

Open Access

https://doi.org/10.18632/oncotarget.21517

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Abstract

Oxalate (Ox) is a metabolic end product that is produced by the kidneys and is associated with several pathological conditions. The accumulation of oxalate in the body is one of the factors that lead to calcium oxalate kidney stones. To simulate the high-concentration Ox environment in vivo, we established an in vitro model of high Ox using renal tubular epithelial (HK-2) cells. Cell viability and proliferation were assessed to evaluate the effects of various concentrations (0, 0.25, 0.5, 1, 2, 4, 5, 8 and 10Mm) of Ox on HK-2 cells to select the optimum concentration and time to extract the exosomes. Treatment with 0, 1, or 2 mM Ox altered the morphology and secretion capacity of exosomes. As the concentration of Ox increased, peak and mean particle size decreased, but exosomes particle concentration, exosome RNA, and exosome protein increased. Size, distribution, and rate of secretion, as well as RNA and protein content, differed among extracellular vesicle subtypes. Furthermore, the three subtypes of exosomes delivered different signal factors in the microenvironment. We therefore speculated that three subtypes of exosomes may play differing roles in intercellular signal communication and the formation of CaOx kidney stones.

Highlights

Kidney stone is a serious disease which is harmful to human health worldwide [1]
The secretion of exosomes is closely related to cell viability; exosomes have been found in the urine of patients with CaOx kidney stones
Cell proliferation and cytotoxicity were evaluated with the Cell Counting Kit-8 (CCK-8) assay, which exhibits high sensitivity and involves no radioactivity [13]

Summary

Introduction

Kidney stone is a serious disease which is harmful to human health worldwide [1]. Pathogenesis of the disease remains unclear. The secretion of exosomes is closely related to cell viability; exosomes have been found in the urine of patients with CaOx kidney stones. We sought to optimize the extraction and identification of exosomes using HK-2 cells exposed to high concentrations of Ox. We found that exosome size and secretion varied under different concentrations of oxalate [12], suggesting that three groups of exosomes may carry different signaling molecules and may play different roles in the micro-environment. We found that exosome size and secretion varied under different concentrations of oxalate [12], suggesting that three groups of exosomes may carry different signaling molecules and may play different roles in the micro-environment This discovery may allow us to explore the mechanisms of signal transduction and targeted regulation of exosomes in stone formation

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