Selective 14-3-3γ induction quenches p-β-catenin Ser37/Bax-enhanced cell death in cerebral cortical neurons during ischemia

Abstract

Ischemia-induced cell death is a major cause of disability or death after stroke. Identifying the key intrinsic protective mechanisms induced by ischemia is critical for the development of effective stroke treatment. Here, we reported that 14-3-3γ was a selective ischemia-inducible survival factor in cerebral cortical neurons reducing cell death by downregulating Bax depend direct 14-3-3γ/p-β-catenin Ser37 interactions in the nucleus. 14-3-3γ, but not other 14-3-3 isoforms, was upregulated in primary cerebral cortical neurons upon oxygen–glucose deprivation (OGD) as measured by quantitative PCR, western blot and fluorescent immunostaining. The selective induction of 14-3-3γ in cortical neurons by OGD was verified by the in vivo ischemic stroke model. Knocking down 14-3-3γ alone or inhibiting 14-3-3/client interactions was sufficient to induce cell death in normal cultured neurons and exacerbate OGD-induced neuronal death. Ectopic overexpression of 14-3-3γ significantly reduced OGD-induced cell death in cultured neurons. Co-immunoprecipitation and fluorescence resonance energy transfer demonstrated that endogenous 14-3-3γ bound directly to more p-β-catenin Ser37 but not p-Bad, p-Ask-1, p-p53 and Bax. During OGD, p-β-catenin Ser37 but not p-β-catenin Ser45 was increased prominently, which correlated with Bax elevation in cortical neurons. OGD promoted the entry of 14-3-3γ into the nuclei, in correlation with the increase of nuclear p-β-catenin Ser37 in neurons. Overexpression of 14-3-3γ significantly reduced Bax expression, whereas knockdown of 14-3-3γ increased Bax in cortical neurons. Abolishing β-catenin phosphorylation at Ser37 (S37A) significantly reduced Bax and cell death in neurons upon OGD. Finally, 14-3-3γ overexpression completely suppressed β-catenin-enhanced Bax and cell death in neurons upon OGD. Based on these data, we propose that the 14-3-3γ/p-β-catenin Ser37/Bax axis determines cell survival or death of neurons during ischemia, providing novel therapeutic targets for ischemic stroke as well as other related neurological diseases.

Piperlongumine selectively kills hepatocellular carcinoma cells and preferentially inhibits their invasion via ROS-ER-MAPKs-CHOP

“…Western blot analysis and fluorescent cytoimmunostaining were performed as described previously [45]. Briefly, equal amounts of total proteins were subjected to mini-PAGE gel electrophoresis and transferred to NC membranes.…”

“…Twenty-four hours after cell seeding, interfering RNAs at 50 nM were transfected into HepG2 cells using Lipofectamine 2000 (Invitrogen, Carlsbad, CA, USA) as previously reported [45]. Two days after siRNA trensfection, the cultures were subjected to PL treatment and the corresponding assays.…”

Decrease of 14–3-3 proteins by glutamate exposure in the cerebral cortex of newborn rats

“…The pro-apoptotic activity of ASK1 is inhibited by interaction with 14-3-3 proteins. Moreover, 14-3-3 acts as a survival factor in oxygen-glucose deprivation-induced cell death [21]. They also demonstrated that knockout of 14-3-3 increases Bax expression, whereas overexpression of 14-3-3 decreases Bax expression [21].…”

Mitochondrial mechanisms of neuronal rescue by F-68, a hydrophilic Pluronic block co-polymer, following acute substrate deprivation

“…Since the initial observations that, after ischemia, BAX is upregulated in central neurons (Krajewski et al, 1995), and translocates to neuronal mitochondria (Cao et al, 2001), BAX has been observed to play a key role in multiple models of ischemia-induced neuronal death (Fan et al, 2012; Lai et al, 2014; Pei et al, 2014; Wang et al, 2011). In addition to BAX, BID has been implicated in neuronal death following OGD in vitro and HI in vivo (Plesnila et al, 2001), as well as in early cytochrome c release following HI (Yin et al, 2002).…”