Activation of Lrrk2 and α-Synuclein in substantia nigra, striatum, and cerebellum after chronic exposure to arsenite

Mechanism of arsenic regulation of mitochondrial damage and autophagy induced synaptic damage through SIRT1 and protective effect of melatonin in HT22 cell

Arsenic (As), a widespread environmental pollutant, can induce severe neurological damage worldwide; however, the underlying mechanisms remain unclear. Sirtuin 1 (SIRT1) has been reported to exert neuroprotective effects against various neurological diseases by resisting mitochondrial damage and autophagy through deacetylation. In this study, we established a model of HT22 cells exposed to NaAsO2 and examined the levels of mitochondrial, autophagy, and synaptic damage in HT22 cells and HT22 cells with high expression of SIRT1 (pre-treated with the agonist SRT1720) 24 h after exposure. Our results suggest that NaAsO2 exposure induces down-regulation of SIRT1, causing mitochondrial damage and activation of autophagy, which in turn leads to synaptic damage. Notably, melatonin (Mel) intervention upregulated SIRT1 and attenuated mitochondrial damage and autophagy, restoring synaptic damage. In conclusion, the results of the present study indicate that As causes neurotoxicity by decreasing SIRT1 production, causing mitochondrial damage and activating autophagy, which provides fundamental data for further study of arsenic neurotoxicity. In addition, blocking this pathway attenuated the synaptic damage of arsenic exposure, which provides a new therapeutic avenue for arsenic neurotoxicity.

Mechanisms of genotoxicity and proteotoxicity induced by the metalloids arsenic and antimony

Arsenic and antimony are metalloids with profound effects on biological systems and human health. Both elements are toxic to cells and organisms, and exposure is associated with several pathological conditions including cancer and neurodegenerative disorders. At the same time, arsenic- and antimony-containing compounds are used in the treatment of multiple diseases. Although these metalloids can both cause and cure disease, their modes of molecular action are incompletely understood. The past decades have seen major advances in our understanding of arsenic and antimony toxicity, emphasizing genotoxicity and proteotoxicity as key contributors to pathogenesis. In this review, we highlight mechanisms by which arsenic and antimony cause toxicity, focusing on their genotoxic and proteotoxic effects. The mechanisms used by cells to maintain proteostasis during metalloid exposure are also described. Furthermore, we address how metalloid-induced proteotoxicity may promote neurodegenerative disease and how genotoxicity and proteotoxicity may be interrelated and together contribute to proteinopathies. A deeper understanding of cellular toxicity and response mechanisms and their links to pathogenesis may promote the development of strategies for both disease prevention and treatment.