Calciprotein particle-induced cytotoxicity via lysosomal dysfunction and altered cholesterol distribution in renal epithelial HK-2 cells

Rina Kunishige, Mai Mizoguchi, Asako Tsubouchi, Kenjiro Hanaoka, Yutaka Miura, Hiroshi Kurosu, Yasuteru Urano, Makoto Kuro-o, Masayuki Murata

Research output: Contribution to journalArticlepeer-review

Abstract

Dietary phosphate overload induces chronic kidney disease (CKD), and calciprotein particles (CPPs), a form of nanoparticle comprising calcium phosphate and serum proteins, has been proposed to cause renal toxicity. However, the mechanism of CPP cytotoxicity in renal tubular cells is unknown. Here we show that in renal proximal tubular epithelial HK-2 cells, endocytosed CPPs accumulate in late endosomes/lysosomes (LELs) and increase their luminal pH by ~ 1.0 unit. This results in a decrease in lysosomal hydrolase activity and autophagic flux blockage without lysosomal rupture and reactive oxygen species generation. CPP treatment led to vulnerability to H2O2-induced oxidative stress and plasma membrane injury, probably because of autophagic flux blockage and decreased plasma membrane cholesterol, respectively. CPP-induced disruption of lysosomal homeostasis, autophagy flux and plasma membrane integrity might trigger a vicious cycle, leading to progressive nephron loss.

Original languageEnglish
Article number20125
JournalScientific reports
Volume10
Issue number1
DOIs
Publication statusPublished - 2020 Dec
Externally publishedYes

ASJC Scopus subject areas

  • General

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