Injury of renal tubular epithelial cells induced by high calcium ion activation of autophagy through the HMGB1/mTOR signaling axis
10.12483/j.issn.1009-8291.2026.05.011
- VernacularTitle:高钙离子通过HMGB1/mTOR信号轴激活自噬致肾小管上皮细胞损伤
- Author:
Mingbin XU
1
;
Shuming HE
1
Author Information
1. Department of Urology, The Second Affiliated Hospital of Hainan Medical University, Haikou 570311, China
- Publication Type:Journal Article
- Keywords:
hypercalciuria;
human renal tubular epithelial cells;
high mobility group box 1;
mammalian target of rapamycinm
- From:
Journal of Modern Urology
2026;31(5):454-459
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the molecular mechanism by which high mobility group box 1 (HMGB1) mediates renal tubular epithelial cell injury in a high-calcium environment. Methods A CaCl_2 concentration gradient (0, 0.5, 1, 2 mg/mL) treatment system was established based on human renal tubular epithelial cells (HK-2 cells). The calcium ioninduced cell injury effects were evaluated with CCK-8 assay, lactate dehydrogenase (LDH) detection, and DAPI staining. The optimal CaCl_2 concentration was selected for subsequent experiments. The secretion level of HMGB1 in the cell supernatant was detected with ELISA, and the expressions of autophagy markers (LC3-Ⅱ/LC3-Ⅰ, p62) and mTOR pathway-related proteins were detected with Western blot. Lentiviral-mediated HMGB1 silencing (shHMGB1) or pretreatment with ethyl pyruvate (EP), a specific inhibitor of HMGB1, was used on HK-2 cells to verify the role of HMGB1 in cell injury. Additionally, the autophagy agonist rapamycin was added to further clarify the role of the mammalian target of rapamycin (mTOR) signaling axis. Results Different concentrations of CaCl_2 promoted the release of HMGB1, activated autophagy, induced renal tubular epithelial cell injury, increased LDH release, and exacerbated nuclear damage. The optimal concentration was 1 mg/mL in the follow-up experiment. Targeted inhibition of HMGB1 significantly alleviated CaCl_2-induced autophagic response and cell injury. The underlying mechanism might involve the inhibition of HMGB1 expression leading to the blockage of the downstream mTOR signaling pathway, thereby preventing excessive autophagy activation.Conclusion The high-calcium environment activates autophagy through the HMGB1/mTOR signaling axis, which may be one of the important mechanisms by which hypercalciuria promotes renal tubular epithelial cell injury.
