Nuclear factor (NF)-κB is a master regulator of pro-inflammatory genes and is upregulated in human immunodeficiency virus 1 (HIV-1) infection. Mechanisms underlying the NF-κB deregulation by HIV-1 are relevant for immune dysfunction in AIDS. We report that in single round HIV-1 infection, or single-pulse PMA stimulation, the HIV-1 Tat transactivator activated NF-κB by hijacking the inhibitor IκB-α and by preventing the repressor binding to the NF-κB complex. Moreover, Tat associated with the p65 subunit of NF-κB and increased the p65 DNA-binding affinity and transcriptional activity. The arginine- and cysteine-rich domains of Tat were required for IκB-α and p65 association, respectively, and for sustaining the NF-κB activity. Among an array of NF-κB-responsive genes, Tat mostly activated the MIP-1α expression in a p65-dependent manner, and bound to the MIP-1α NF-κB enhancer thus promoting the recruitment of p65 with displacement of IκB-α; similar findings were obtained for the NF-κB-responsive genes CSF3, LTA, NFKBIA and TLR2. Our results support a novel mechanism of NF-κB activation via physical interaction of Tat with IκB-α and p65, and may contribute to further insights into the deregulation of the inflammatory response by HIV-1.
SUMMARYObjective: Statins (3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitors) exert cholesterol-independent pleiotropic effects that include antithrombotic, antiinflammatory, and antioxidative properties. Moreover, both in vitro and in vivo studies have shown neuroprotective, antiseizure, and antiexcitotoxic effects of statins, suggesting their potential role in the treatment of neurologic diseases. Only a few studies have investigated whether statins modulate absence seizure activity and epileptogenesis. Methods: We investigated the effects of atorvastatin (5 and 10 mg/kg/day), simvastatin (10 mg/kg/day), and pravastatin (10 and 30 mg/kg/day), given orally for 17 consecutive weeks (starting at 45 days of age), on the development of absence seizures (electroencephalography [EEG] recordings), depressive-like behavior (forced swimming test [FST]), and anxiety levels (open field test [OF]) in Wistar Albino Glaxo/Rijswijk rats (WAG/Rij) rats at the age of 6 months (1 month after suspension). WAG/Rij rats are a genetic animal model of absence epilepsy, epileptogenesis, and mild-depression comorbidity. The effects of statins were also studied after acute intraperitoneal injection for 4 h after administration of various doses in 6-months-old rats. Plasma cholesterol levels were measured throughout drug treatment. Results: We found that early long-term statin treatment possesses antiepileptogenic properties, reduced immobility time in the FST, and reduced anxiety in the OF, whereas they were not effective against established absence seizures when acutely administered. The observed effects were not related to changes in plasma cholesterol levels, which remained unchanged during drug treatment. Significance: Our results suggest that statins administration might be a possible intervention and promising strategy for preventing the epileptogenesis and/or behavioral comorbidity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.