Hippocampal nuclear factor kappa B accounts for stress‐induced anxiety behaviors via enhancing neuronal nitric oxide synthase (nNOS)‐carboxy‐terminal PDZ ligand of nNOS‐Dexras1 coupling

Abstract

Anxiety disorders are associated with a high social burden worldwide. Recently, increasing evidence suggests that nuclear factor kappa B (NF-κB) has significant implications for psychiatric diseases, including anxiety and depressive disorders. However, the molecular mechanisms underlying the role of NF-κB in stress-induced anxiety behaviors are poorly understood. In this study, we show that chronic mild stress (CMS) and glucocorticoids dramatically increased the expression of NF-κB subunits p50 and p65, phosphorylation and acetylation of p65, and the level of nuclear p65 in vivo and in vitro, implicating activation of NF-κB signaling in chronic stress-induced pathological processes. Using the novelty-suppressed feeding (NSF) and elevated-plus maze (EPM) tests, we found that treatment with pyrrolidine dithiocarbamate (PDTC; intra-hippocampal infusion), an inhibitor of NF-κB, rescued the CMS- or glucocorticoid-induced anxiogenic behaviors in mice. Microinjection of PDTC into the hippocampus reversed CMS-induced up-regulation of neuronal nitric oxide synthase (nNOS), carboxy-terminal PDZ ligand of nNOS (CAPON), and dexamethasone-induced ras protein 1 (Dexras1) and dendritic spine loss of dentate gyrus (DG) granule cells. Moreover, over-expression of CAPON by infusing LV-CAPON-L-GFP into the hippocampus induced nNOS-Dexras1 interaction and anxiety-like behaviors, and inhibition of NF-κB by PDTC reduced the LV-CAPON-L-GFP-induced increases in nNOS-Dexras1 complex and anxiogenic-like effects in mice. These findings indicate that hippocampal NF-κB mediates anxiogenic behaviors, probably via regulating the association of nNOS-CAPON-Dexras1, and uncover a novel approach to the treatment of anxiety disorders.

nNOS‐CAPON blockers produce anxiolytic effects by promoting synaptogenesis in chronic stress‐induced animal models of anxiety

“…Tat‐CAPON12C (YGRKKRRQRRRELGDSLDDEIAV), a recombinant fusion protein with the action to dissociate nNOS–CAPON, and its control peptide Tat‐CAPON12C/A22D (YGRKKRRQRRRELGDSLDDEIDV) were purchased from Shanghai GL Biochem Ltd. ZLc‐002 and Tat‐CAPON12C were dissolved in 0.9% sterile saline and corticosterone (CORT, Cat# 27840, Sigma‐Aldrich, St Louis, MO, USA) in 0.1% DMSO. Corticosterone (10 μM), ZLc‐002 (10 μM) and Tat‐CAPON12C (50 nM) were delivered into the dentate gyrus (DG) of the hippocampus by microinjection through a pre‐implanted cannula as described previously (Zhu et al, 2018). In brief, mice were anaesthetised with 2% isoflurane and maintained under 1.5%–2.0% isoflurane.…”

“…Corticosterone (10 μM) or its vehicle was delivered into the dentate gyrus of the hippocampus daily using a microinjection through a pre‐implanted cannula (30 gauge, 4.0 mm; RWD Life Science Co., Ltd) terminating 0.50 mm below the tip of the guides and connected by polyethylene tubing (PE‐10) to a 10‐μl Hamilton syringe. The administration was controlled by an infusion pump programmed to deliver a volume of 1 μl at a flow‐rate of 0.1 μl·min −1 , as described previously (Zhu et al, 2018). ZLc‐002 (10 μM, 1 μl, administrated 30 min after corticosterone), Tat‐CAPON12C (50 nM, 1 μl, administrated 30 min after corticosterone), its vehicle or control peptide was infused into the hippocampus between day 21 and day 27 of corticosterone(10 μM, 1 μl) treatment via a pre‐implanted cannula.…”

“…The chronic mild stress procedure was designed as described in our previous studies (Cai et al, 2019; Ducottet, Griebel, & Belzung, 2003; Zhang et al, 2010; Zhou et al, 2007; Zhu et al, 2018). It consisted of a variety of mild stressors (Table 1).…”

“…The behavioural tests were performed as described in our previous study (Zhang et al, 2010; Zhu et al, 2018), including novelty‐suppressed feeding (NSF), as well as the elevated plus maze (EPM), the open field (OF) and light–dark (LD) tests. The NSF test was carried out over a 5‐min period.…”

“…Our previous studies have shown that hippocampal neuronal NOS (nNOS) plays an important role in regulating anxiety behaviour. In particular, hippocampal nNOS– Ccarboxyl‐terminal PDZ ligand of neuronal nitric oxide synthase protein (CAPON) coupling may serve as a new target for developing potential anxiolytics (Hu et al, 2012; Zhu et al, 2014; Zhu et al, 2018). Fortunately, among the many nNOS–CAPON blockers that we have designed and synthesised, ZLc‐002 and Tat‐CAPON12C have significant anxiolytic‐like effects (Zhu et al, 2014).…”