MiRNA-210 modulates a nickel-induced cellular energy metabolism shift by repressing the iron-sulfur cluster assembly proteins ISCU1/2 in Neuro-2a cells

The cellular energy metabolism shift, characterized by the inhibition of oxidative phosphorylation (OXPHOS) and enhancement of glycolysis, is involved in nickel-induced neurotoxicity. MicroRNA-210 (miR-210) is regulated by hypoxia-inducible transcription factor-1a (HIF-1a) under hypoxic conditions and controls mitochondrial energy metabolism by repressing the ironsulfur cluster assembly protein (ISCU1/2). ISCU1/2 facilitates the assembly of iron-sulfur clusters (ISCs), the prosthetic groups that are critical for mitochondrial oxidation-reduction reactions. This study aimed to investigate whether miR-210 modulates alterations in energy metabolism after nickel exposure through suppressing ISCU1/2 and inactivating ISCs-containing metabolic enzymes. We determined that NiCl2 exposure leads to a significant accumulation of HIF-1a, rather than HIF-1b, in Neuro-2a cells. The miR-210 overexpression and ISCU1/2 downregulation was observed in a dose-and time-dependent manner. The gain-offunction and loss-of-dysfunction assays revealed that miR-210 mediated the ISCU1/2 suppression, energy metabolism alterations, and ISC-containing metabolic enzyme inactivation after nickel exposure. In addition, the impact of miR-210 on ISC-containing metabolic enzymes was independent from cellular iron regulation. Overall, these data suggest that repression of miR-210 on ISCU1/2 may contribute to HIF-1a-triggered alterations in energy metabolism after nickel exposure. A better understanding of how nickel impacts cellular energy metabolism may facilitate the elucidation of the mechanisms by which nickel affects the human health.