NF-κB in mitochondria regulates PC12 cell apoptosis following lipopolysaccharide-induced injury

Abstract

Objective: To determine the relationship between nuclear transcription factor κB (NF-κB) expression in mitochondria and neuronal cell apoptosis after lipopolysaccharide (LPS)-induced injury. Methods: The effect of drug administration on PC12 cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and Hoechst 33342 staining. The morphology and function of mitochondria were investigated with electron microscopy and rhodamine 123, respectively. The activity of adenine nucleotide translocase 1 (ANT1), lipid peroxide, and antiperoxidase enzymes was measured by enzyme-linked immunosorbent assay (ELISA). Relative expression levels of NF-κB were measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Results: Pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) and nerve growth factor (NGF) not only reduced apoptosis but also had a protective effect on mitochondrial structure and function in a PC12 cell LPS damage model. The subcellular distribution of NF-κB demonstrated that NGF, diterpene acid atractyloside (ATR, an ANT1 antagonist), and PDTC alleviated increases in mitochondrial NF-κB after LPS-induced injury. Conclusions: (1) NF-κB is activated in mitochondria via uptake of ANT1 during apoptosis following LPS-induced injury in neuronal cells; (2) NGF not only decreases the activity of NF-κB but also reduces ANT1 activity, which in turn decreases NF-κB levels in mitochondria and suppresses mitochondria-mediated apoptosis.