Untargeted metabolomics study of cadmium exposure–induced metabolic reprogramming in renal tubular epithelial cells
- VernacularTitle:镉暴露诱导肾小管上皮细胞代谢重编程的非靶向代谢组学研究
- Author:
Riming CHEN
1
;
Huanhuan ZHU
2
;
Xiying TANG
1
;
Haiyan CHU
1
;
Zhengdong ZHANG
1
Author Information
- Publication Type:Experiment
- Keywords: cadmium; nephrotoxicity; untargeted metabolomics; mitochondrial dysfunction; metabolic reprogramming
- From: Journal of Environmental and Occupational Medicine 2026;43(8):1008-1017
- CountryChina
- Language:Chinese
- Abstract: Background Cadmium (Cd) is a highly toxic heavy metal. Chronic low-dose cadmium exposure can lead to renal tubular dysfunction. However, the precise mechanisms by which cadmium induces renal tubular injury through disruption of intracellular metabolic networks remain incompletely understood. Objective To investigate the toxic effects of cadmium exposure on human renal tubular epithelial cells (HK-2) and to elucidate the associated metabolic regulatory network from the perspective of metabolic reprogramming. Methods An in vitro HK-2 cell injury model was established using 5 μmol·L−1 cadmium chloride (CdCl2). The expression of the renal injury marker kidney injury molecule-1 (KIM-1) was determined by Western blot (WB). Glycolytic capacity was evaluated by metabolic flux analysis. Mitochondrial reactive oxygen species (ROS) production was assessed with a fluorescent probe. Mitochondrial membrane potential (MMP) was evaluated after JC-1 staining. Intracellular adenosine triphosphate (ATP) levels were measured using an ATP assay kit. In addition, untargeted metabolomics analysis was conducted to characterize alterations in the intracellular metabolic fingerprint profile and to explore the metabolic pathway changes underlying cadmium-induced renal tubular epithelial cell injury. Results Cadmium exposure induced injury in HK-2 cells, as indicated by mitochondrial membrane depolarization, increased mitochondrial ROS levels, and decreased intracellular ATP levels. Metabolic flux analysis further revealed significant metabolic reprogramming, characterized by compensatory increases in basal glycolytic rate and maximal glycolytic capacity. Untargeted metabolomics showed depletion of the long-chain acylcarnitine pool and deficiency of key metabolic cofactors, suggesting impaired fatty acid oxidation and mitochondrial energy metabolism. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that the differential metabolites were mainly enriched in oxidative phosphorylation and glycerophospholipid metabolism. Correlation analysis showed that acylcarnitines were negatively correlated with nucleic acid metabolism-related metabolites, whereas ATP was positively correlated with lysophosphatidylcholine, suggesting that cadmium exposure-induced mitochondrial dysfunction may be accompanied by abnormal DNA metabolism and lipid peroxidation. Conclusion Cadmium exposure could induce impaired mitochondrial function, and promote glycolytic metabolic reprogramming in renal tubular epithelial cells. These findings provide new insights into the metabolic mechanisms underlying cadmium-induced nephrotoxicity and may help identify potential metabolic targets for intervention.
