The acetylation of RelA in Lys310 dictates the NF-κB-dependent response in post-ischemic injury

Abstract

The activation of nuclear factor kappa B (NF-κB) p50/RelA is a key event in ischemic neuronal injury, as well as in brain ischemic tolerance. We tested whether epigenetic mechanisms affecting the acetylation state of RelA might discriminate between neuroprotective and neurotoxic activation of NF-κB during ischemia. NF-κB activation and RelA acetylation were investigated in cortices of mice subjected to preconditioning brain ischemia or lethal middle cerebral artery occlusion (MCAO) and primary cortical neurons exposed to preconditioning or lethal oxygen-glucose deprivation (OGD). In mice subjected to MCAO and in cortical neurons exposed to lethal OGD, activated RelA displayed a high level of Lys310 acetylation in spite of reduced total acetylation. Also, acetylated RelA on Lys310 interacted strongly with the CREB-binding protein (CBP). Conversely, RelA activated during preconditioning ischemia appeared deacetylated on Lys310. Overexpressing RelA increased Bim promoter activity and neuronal cell death both induced by lethal OGD, whereas overexpressing the acetylation-resistant RelA-K310R, carrying a mutation from Lys310 to arginine, prevented both responses. Pharmacological manipulation of Lys310 acetylation by the sirtuin 1 activator resveratrol repressed the activity of the Bim promoter and reduced the neuronal cell loss. We conclude that the acetylation of RelA in Lys310 dictates NF-κB-dependent pro-apoptotic responses and represents a suitable target to dissect pathological from neuroprotective NF-κB activation in brain ischemia.

PEA and luteolin synergistically reduce mast cell-mediated toxicity and elicit neuroprotection in cell-based models of brain ischemia

“…The combination of PEA and luteolin promotes synergistic neuroprotection in neurons exposed to OGD To investigate whether PEA and luteolin were also endowed with direct neuroprotective property, different concentrations of the two molecules, alone or in association, were tested on neurons previously exposed to 3 h of OGD. The drugs were added to the cell cultures after the anoxic event and maintained in the recovery medium for the following 24 h. In line with previous data (Lanzillotta et al, 2013(Lanzillotta et al, , 2010Sarnico et al, 2009), the relative LDH release in control neurons and in neurons subjected to 3 h of OGD was 0.1 7 0.02 and 0.327 0.02 respectively (mean 7 SEM). PEA did not exhibit significant neuroprotective effect at any concentration tested in the range 10 pM À5 μM (Fig.…”

“…This system allowed us to model the interactions between neurons and MCs in pathophysiological conditions of cerebral ischemia. Pure neurons or neurons-MC/9 cells cocultures were subjected to 6 h of OGD, followed by 24 h of reperfusion, in accordance with the OGD experimental procedure we developed for neuronal cultures (Lanzillotta et al, 2013(Lanzillotta et al, , 2010Sarnico et al, 2009). Neurons-MC/9 cells co-cultures displayed higher cell death when compared to pure neurons (Fig.…”

Identification of autophagy signaling network that contributes to stroke in the ischemic rodent brain via gene expression

“…Brain tissue damage has also been correlated with the dysregulated NFKB1 [43] , blockade of which protects the brain against ischemic damage by regulating infl ammatory responses [44,45] . NFKB1 combines with RELA to form the NFKB1/ RELA complex that is a key molecule in the progression of ischemic stroke [46] . Notably, NFKB1/RELA induces pro-apoptotic transcription in acute brain ischemia and its activation is an important event in ischemic neuronal injury [47] .…”

NF‐κB and epigenetic mechanisms as integrative regulators of brain resilience to anoxic stress

“…What remained to be clarified was the mechanism of neuroprotection elicited by NF-κB in preconditioning ischemia (Blondeau et al, 2001). Indeed, a similar pattern of p50/RelA without c-Rel activation was found in brains of mice exposed to preconditioning or lethal ischemia (Lanzillotta et al, 2010 Bim, Noxa Fig. 1 -NF-κB dimer composition and post-transcriptional modifications of NF-κB subunits represent diverse levels of regulation of NF-κB activity in response to environmental stimuli affecting neuron survival.…”

“…In contrast, in sublethal ischemia NF-κB contributes to the preconditioning effect by dampening its own subsequent full activation through the activation of IκBα transcription (Blondeau et al, 2001;Ridder and Schwaninger, 2009). We afforded the dual effect of NF-κB activation in preconditioning and lethal ischemia using neuronal cells exposed to oxygen glucose deprivation (OGD) and mice subjected to middle cerebral artery occlusion (MCAO) (Lanzillotta et al, 2010;Pizzi et al, 2009). After exposure to lethal ischemia, neuronal nuclei displayed a high level of p50/RelA activation (Crack et al, 2006;Inta et al, 2006) and decreased level of c-Relcontaining dimers (Sarnico et al, 2009a(Sarnico et al, , 2009b.…”