Nanoplastics-induced hormesis enhances cadmium bioaccumulation in nematodes by stimulating glutathione synthesis

Caijiao He; Shuang Zhang; Yi Chi; Jing Wang; Jiang Xu; Jie Hou; Daohui Lin

doi:10.1016/j.scitotenv.2025.179983

Nanoplastics-induced hormesis enhances cadmium bioaccumulation in nematodes by stimulating glutathione synthesis

Sci Total Environ. 2025 Jun 30:993:179983. doi: 10.1016/j.scitotenv.2025.179983. Online ahead of print.

Authors

Caijiao He¹, Shuang Zhang¹, Yi Chi², Jing Wang³, Jiang Xu⁴, Jie Hou⁵, Daohui Lin⁴

Affiliations

¹ Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
² Hangzhou Ecological and Environmental Monitoring Center of Zhejiang Province, Hangzhou 310058, China.
³ Ecological and Environmental Monitoring Center of Zhejiang Province, Hangzhou 310012, China.
⁴ Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; State Key Laboratory of Soil Pollution Control and Safety, Hangzhou 310058, Zhejiang University, China.
⁵ Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; State Key Laboratory of Soil Pollution Control and Safety, Hangzhou 310058, Zhejiang University, China. Electronic address: hou-jie@zju.edu.cn.

PMID: 40592214
DOI: 10.1016/j.scitotenv.2025.179983

Abstract

Nanoplastics (NPs) induce hormesis at environmental concentrations due to their relatively low toxicity; however, this phenomenon can alter the response of biota to coexisting heavy metals, resulting in unknown combined risks. In this study, we investigated the joint effects of cadmium (Cd) and four polystyrene nanoplastics (PS-NPs) with different sizes (100 nm and 500 nm) and surface modifications (-NH₂ and -COOH) on Caenorhabditis elegans, focusing on how NPs-induced bioresponses contribute to Cd accumulation in nematodes. Different from traditional views, the results show that NPs enhance Cd accumulation primarily through hormesis rather than direct adsorption. Coexposure with the four PS-NPs significantly increased Cd bioaccumulation by 1.33-1.71-fold compared to Cd-alone treatments, attributed to elevated storage of glutathione (GSH)-Cd complexes in gut granules. Transcriptomic and metabolomic analyses revealed a 14.0-20.6 % upregulation of metal-response molecules, driven by activation of sulfur-containing amino acid metabolism pathways. These molecular bioresponses doubled GSH synthesis, promoting GSH-Cd complexation and Cd accumulation. Our findings underscore the overlooked role of NPs-induced hormesis in amplifying heavy metal bioaccumulation and associated risks.

Keywords: Bioaccumulation; Combined exposure; Ecological risk; Heavy metal; Nanoplastics.