Open AccessCadmium Impairs Autophagy Leading to Apoptosis by Ca2+-Dependent Activation of JNK Signaling Pathway in Neuronal Cells
Author(s) -
Chong Xu,
Sujuan Chen,
Ming Xu,
Xiaoling Chen,
Xiaoxue Wang,
Hai Zhang,
Xiaoqing Dong,
Ruijie Zhang,
Xin Chen,
Wei Gao,
Shile Huang,
Long Chen
Publication year - 2021
Publication title -
neurochemical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.102
H-Index - 116
eISSN - 1573-6903
pISSN - 0364-3190
DOI - 10.1007/s11064-021-03341-x
Subject(s) - autophagy , microbiology and biotechnology , neurotoxicity , apoptosis , intracellular , neurodegeneration , programmed cell death , signal transduction , biology , chemistry , biochemistry , medicine , disease , organic chemistry , toxicity
Autophagy, a process for self-degradation of intracellular components and dysfunctional organelles, is closely related with neurodegenerative diseases. It has been shown that cadmium (Cd) induces neurotoxicity partly by impairing autophagy. However, the underlying mechanism is not fully elucidated. In this study, we show that Cd induced expansion of autophagosomes with a concomitant abnormal expression of autophagy-related (Atg) proteins in PC12 cells and primary murine neurons. 3-MA, a classical inhibitor of autophagy, attenuated Cd-induced expansion of autophagosomes and apoptosis in the cells. Further investigation demonstrated that Cd activated JNK pathway contributing to autophagosome expansion-dependent neuronal apoptosis. This is supported by the findings that pharmacological inhibition of JNK with SP600125 or expression of dominant negative c-Jun markedly attenuated Cd-induced expansion of autophagosomes and abnormal expression of Atg proteins, as well as apoptosis in PC12 cells and/or primary neurons. Furthermore, we noticed that chelating intracellular free Ca 2+ ([Ca 2+ ] i ) with BAPTA/AM profoundly blocked Cd-elicited activation of JNK pathway and consequential expansion of autophagosomes, abnormal expression of Atg proteins, and apoptosis in the neuronal cells. Similar events were also seen following prevention of [Ca 2+ ] i elevation with EGTA or 2-APB, implying a Ca 2+ -dependent mechanism involved. Taken together, the results indicate that Cd impairs autophagy leading to apoptosis by Ca 2+ -dependent activation of JNK signaling pathway in neuronal cells. Our findings highlight that manipulation of intracellular Ca 2+ level and/or JNK activity to ameliorate autophagy may be a promising intervention against Cd-induced neurotoxicity and neurodegeneration.