1. Tetrabromobisphenol A induced p38-MAPK/AMPKα activation downstream-triggered CHOP signal contributing to neuronal apoptosis and death.
- Author
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Liu JM, Liu SH, Fu SC, Lai WC, Fang KM, Lin KA, Ke JA, Kuo CY, Su CC, and Chen YW
- Abstract
Tetrabromobisphenol A (TBBPA), a brominated flame retardant (BFR), has been implicated as the neurotoxic effects in mammalian. However, the exact mechanisms underlying TBBPA-induced neurotoxicity remain unclear. In the present study, Neuro-2a cells, a mouse neural crest-derived cell line, were used to examine the mechanism of TBBPA-induced neuronal cytotoxicity. TBBPA exposure caused alterations in cell viability and mitochondrial membrane potential (MMP) and induction of apoptotic events, such as increased apoptotic cell population and cleaved caspase-3, -7, -9, and poly (ADP-ribose) polymerase (PARP) protein expression). TBBPA exposure triggered CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) activation. Transfection with CHOP-specific small interfering RNA (siRNA) obviously prevented the expression of CHOP protein and markedly attenuated MMP loss, and caspase-3 and -7 activation in TBBPA-exposed Neuro-2a cells. In addition, TBBPA exposure significantly evoked the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular-signal regulated kinase1/2 (ERK1/2), p38-mitogen-activated protein kinase (p38-MAPK), and AMP-activated protein kinase (AMPK)α proteins. Pretreatment of cells with pharmacological inhibitors of p38-MAPK (SB203580) and AMPK (compound C), but not inhibitors of JNK (SP600125) or ERK1/2 (PD98059), effectively prevented the increase in caspase-3 activity, MMP loss, and activated CHOP and cleaved caspase-3 and -7 protein expression in TBBPA-treated cells. Notably, transfection with either p38α-MAPK- or AMPKα1/2-specific siRNAs markedly attenuated the expression of CHOP, and cleaved caspase-3 and -7. Interestingly, transfection with each siRNA significantly reduced the TBBPA-induced phosphorylation of p38-MAPK and AMPKα proteins. Collectively, these findings suggest that CHOP activation-mediated mitochondria-dependent apoptosis contributes to TBBPA-induced neurotoxicity. An interdependent p38-MAPK and AMPKα signaling-regulated apoptotic pathway may provide new insights into the mechanism understanding TBBPA-elicited neurotoxicity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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