Role of IKK/NF-κB signaling in extinction of conditioned place aversion memory in rats

Protective Role of Acetate Against Depressive-Like Behaviour Associated with Letrozole-Induced PCOS Rat Model: Involvement of HDAC2 and DNA Methylation

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age. PCOS has been demonstrated to induce depressive-like behaviour. Epigenetic alterations such as histone deacetylation (HDAC) and DNA methylation have been suggested in major depression. However, their effects with respect to neuroinflammation are not clear. This study therefore investigated the pathogenic involvement of epigenetic changes in PCOS-associated depression and the protective role of HDACi, especially acetate. Virgin female Wistar rats (140 ± 10 g) were assigned into four groups: the groups received vehicle (control), acetate (200 mg/kg), letrozole (1 mg/kg) and letrozole plus acetate, respectively. The administrations were done concomitantly by oral gavage for 21 days. Treatment with letrozole caused hyperandrogenism, hypoestrogenism, hyperinsulinemia and multiple ovarian cysts/degenerated follicles. In addition, these animals showed depressive-like behaviours and increased expression of HDAC2 and DNA methyltransferase in PFC and hippocampal tissues. Biochemical analyses showed elevated levels of NF-κB, malondialdehyde and acetylcholine (ACH) with glutathione depletion in PFC and hippocampus as well as elevated plasma malondialdehyde and impaired anti-oxidant system in letrozole-treated animals. Histological analysis of PFC and hippocampus showed neurodegeneration in letrozole-treated animals compared with control. However, these alterations were attenuated when treated with acetate. The study demonstrates that PCOS-associated depression is characterised by neuroinflammation and elevated ACH levels, accompanied by increased expression of HDAC2/DNA methyltransferase in PFC and hippocampus. Besides, the study suggests that acetate protects against PCOS-associated depression through suppression of prefrontal and hippocampal DNA methylation and prefrontal but not hippocampal HDAC2 expression.

CaMKIIδ Promotes Synaptic Plasticity under Terahertz Wave Radiation by Activation of the NF-κB Pathway

Terahertz waves have been attracting more attention because of their growing applications in brain science. Most of the studies have demonstrated that terahertz waves have a certain positive impact on neurons. They can promote the growth of ganglion processes and the release of neurotransmitters, but the specific mechanism is still largely unexplored. Our study found that terahertz waves could promote neuronal excitability. Moreover, numerous differentially expressed proteins were uncovered via proteomic analysis. Among them, CaMKIIδ is a subunit of CaMKII and could promote the release of neuronal transmitters, regulate the excitability of neurons, and enhance synaptic plasticity. We further demonstrated that CaMKIIδ actively increased synaptic plasticity through the NF-κB pathway. This study provided a potential target for nerve repair and disease treatment.

Gentianella acuta mitigates cardiovascular damage and inflammation in diet-induced hypercholesterolaemic rats

Gentianella acuta (G. acuta) has been widely used as a traditional medicine by Chinese Mongolian populations for the treatment of heart diseases and has also been tested in modern pharmacological experiments. However, the effects of G. acuta on cardiovascular damage and inflammation under conditions of hypercholesterolaemia remain unclear. The present study investigated the effects and mechanisms of the water extract of G. acuta on cardiovascular damage and inflammation caused by a high-cholesterol diet. Male Sprague-Dawley rats were fed a high-cholesterol diet for 4 weeks to establish the hypercholesterolaemia rat model, and they were administered physiological saline or 1.2 g/kg of G. acuta by gavage starting from the 15th day. After the last administration, the blood, heart and thoracic aorta samples were collected and examined. It was revealed that G. acuta treatment could ameliorate cardiomyocyte disorder and thoracic aortic vessel wall damage, reduce serum lipid levels and inflammatory factors and improve heart function. Compared with the Model group, the serum levels of triglycerides, total cholesterol, low-density lipoprotein and tumour necrosis factor-α were decreased, and the high-density lipoprotein and interleukin-10 levels were increased in the Model-G group. Moreover, in both the heart and thoracic aorta, G. acuta reduced the expression and phosphorylation of inhibitor of nuclear factor kappa-B kinase β (IKKβ), inhibitor of NF-κB-α (IκBα) and p-nuclear factor kappa-B (NF-κB). Therefore, G. acuta may exert an inhibitory effect on the IKK/IκB/NF-κB signalling pathway to protect the heart and thoracic aorta in hypercholesterolaemic rats.

Induction of ROS generation and NF-κB activation in MARC-145 cells by a novel porcine reproductive and respiratory syndrome virus in Southwest of China isolate

Background

Porcine reproductive and respiratory syndrome virus (PRRSV) is the cause of an economically important swine disease that has devastated the swine industry since the late 1980s. The aim of the present study was to investigate the interaction between reactive oxygen species (ROS) and NF-κB by PRRSV infection.

Results

We isolated the local strain of PRRSV from southwest China, designated YN-2011, then sequenced and analyzed the genome. YN-2011 was then used to evaluate the interaction of ROS and NF-κB. In PRRSV infected MARC-145 cells, there was a time-dependent increase in ROS and Maleic Dialdehyde (MDA). Accordingly, NF-κB activation was also increased as PRRSV infection progressed. Degradation of IκB mRNA was detected late in PRRSV infection, and overexpression of the dominant negative form of IκBα significantly suppressed NF-κB induced by PRRSV.

Conclusions

The results indicate that the generation of ROS is involved in PRRSV replication and this progression is associated with the alteration in NF-κB activity induced by ROS. These results should extend our better understanding the interaction between PRRSV and host MARC-145 cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-015-0480-z) contains supplementary material, which is available to authorized users.

Memory labilization in reconsolidation and extinction--evidence for a common plasticity system?

Reconsolidation and extinction are two processes occurring upon memory retrieval that have received great attention in memory research over the last decade, partly due to their purported potential in the treatment of anxiety disorders. Due to their opposite behavioral effects, the two phenomena have usually been considered as separate entities, with few attempts to build a unified view of how both could be produced by similar mechanisms. Based on computational modeling, we have previously proposed that reconsolidation and extinction are behavioral outcomes of the same set of plasticity systems, albeit working at different synapses. One of these systems seems to be pharmacologically similar to the one involved in initial memory consolidation, and likely involves traditional Hebbian plasticity, while the second seems to be more involved with the labilization of existing memories and/or synaptic changes. In this article, we review the evidence for the existence of a plasticity system specifically involved in memory labilization, as well as its possible molecular requirements, anatomical substrates, synaptic mechanisms and physiological roles. Based on these data, we propose that the field of memory updating might ultimately benefit from a paradigm shift in which reconsolidation and extinction are viewed not as separate processes but as different instantiations of plasticity systems responsible for reinforcement and labilization of synaptic changes.

PMS1077 sensitizes TNF-α induced apoptosis in human prostate cancer cells by blocking NF-κB signaling pathway

Our previous studies have demonstrated that PMS1077, a platelet-activating factor (PAF) antagonist, could induce apoptosis of Raji cells. However, the mechanism of action has not yet been determined. The nuclear transcription factor-kappa B (NF-κB) signaling pathway plays a critical role in tumor cell survival, proliferation, invasion, metastasis, and angiogenesis, so we determined the effects of PMS1077 and its structural analogs on tumor necrosis factor-α (TNF-α) induced activation of NF-κB signaling. In this study, we found that PMS1077 inhibited TNF-α induced expression of the NF-κB regulated reporter gene in a dose dependent manner. Western blot assay indicated that PMS1077 suppressed the TNF-α induced inhibitor of κB-α (IκB-α) phosphorylation, IκB-α degradation, and p65 phosphorylation. PMS1077 consistently blocked TNF-α induced p65 nuclear translocation as demonstrated in the immunofluorescence assay used. Docking studies by molecular modeling predicted that PMS1077 might interact directly with the IκB kinase-β (IKK-β) subunit. These results suggested that PMS1077 might suppress the activation of NF-κB by targeting IKK-β involved in the NF-κB signaling pathway. Finally, we showed that PMS1077 sensitized cells to TNF-α induced apoptosis by suppressing the expression of NF-κB regulated anti-apoptotic genes. Our results reveal a novel function of PMS1077 on the NF-κB signaling pathway and imply that PMS1077 can be considered as an anti-tumor lead compound.