Glycogen synthase kinase-3β is critical for Interferon-α-induced serotonin uptake in human Jurkat T cells

Isoorientin Inhibits Inflammation in Macrophages and Endotoxemia Mice by Regulating Glycogen Synthase Kinase 3β

Isoorientin has anti-inflammatory effects; however, the mechanism remains unclear. We previously found isoorientin is an inhibitor of glycogen synthase kinase 3β (GSK3β) in vitro. Overactivation of GSK3β is associated with inflammatory responses. GSK3β is inactivated by phosphorylation at Ser9 (i.e., p-GSK3β). Lithium chloride (LiCl) inhibits GSK3β and also increases p-GSK3β (Ser9). The present study investigated the anti-inflammatory effect and mechanism of isoorientin via GSK3β regulation in lipopolysaccharide- (LPS-) induced RAW264.7 murine macrophage-like cells and endotoxemia mice. LiCl was used as a control. While AKT phosphorylates GSK3β, MK-2206, a selective AKT inhibitor, was used to activate GSK3β via AKT inhibition (i.e., not phosphorylate GSK3β at Ser9). The proinflammatory cytokines TNF-α, IL-6, and IL-1β were detected by ELISA or quantitative real-time PCR, while COX-2 by Western blotting. The p-GSK3β and GSK3β downstream signal molecules, including NF-κB, ERK, Nrf2, and HO-1, as well as the tight junction proteins ZO-1 and occludin were measured by Western blotting. The results showed that isoorientin decreased the production of TNF-α, IL-6, and IL-1β and increased the expression of p-GSK3β in vitro and in vivo, similar to LiCl. Coadministration of isoorientin and LiCl showed antagonistic effects. Isoorientin decreased the expression of COX-2, inhibited the activation of ERK and NF-κB, and increased the activation of Nrf2/HO-1 in LPS-induced RAW264.7 cells. Isoorientin increased the expressions of occludin and ZO-1 in the brain of endotoxemia mice. In summary, isoorientin can inhibit GSK3β by increasing p-GSK3β and regulate the downstream signal molecules to inhibit inflammation and protect the integrity of the blood-brain barrier and the homeostasis in the brain.

Biological mechanisms of depression following treatment with interferon for chronic hepatitis C: A critical systematic review

BACKGROUND

A significant subset of patients infected by the hepatitis C virus (HCV) develops a major depressive episode (MDE) during Interferon-alpha (IFN-α) based immunotherapy. We performed a systematic review of studies which examined biological mechanisms contributing to the onset of a MDE during IFN-α-based immunotherapy for HCV.

METHODS

Major electronic databases were searched from inception up until 15th February 2016 for peer-reviewed prospective studies that had enrolled HCV infected patients who received IFN-α treatment. A diagnosis of MDE had to be established by means of a standardized diagnostic interview at baseline and endpoint.

RESULTS

Eight unique references met inclusion criteria. A total of 826 participants with HCV (37.3% females, mean age 46.7 years) were included in this systematic review. The overall MDE incidence rate was 34.8%, with follow-up ranging between 4 and 48 weeks. The methodological quality varied across selected studies. It was observed that Interleukin-6, salivary cortisol, arachidonic acid / eicosapentaenoicacid plus docosahexaenoic acid ratio, and genetic polymorphisms may present variations which are linked to a predisposition to INF-α-induced depression.

LIMITATIONS

A meta-analysis could not be performed due to the diverse biological mechanisms investigated and the lack of replicated evidence.

CONCLUSIONS

This systematic review indicates that several potential mechanisms may be implicated in the onset of a MDE following IFN-α-based immunotherapy for chronic HCV. However, replicated evidence is lacking and therefore the mechanisms involved in IFN-α-induced depression in humans remain unclear.

Insights from interferon-α-related depression for the pathogenesis of depression associated with inflammation

Interferon-α (IFN-α) is a pleiotropic cytokine that is administered as a therapeutic in highly prevalent medical conditions such as chronic hepatitis C and B virus infection, melanoma and lymphoma. IFN-α induces, to a clinically relevant degree, concentration, memory, drive and mood disturbances in almost half of all patients. For this reason, IFN-α is increasingly being replaced by more specifically acting drugs. In the past decades, IFN-α has offered a valuable insight into the pathogenesis of major depression, particularly in settings associated with inflammation. IFN-α triggers immune responses, hypothalamo-pituitary-adrenal axis abnormalities and disturbances of brain metabolism resembling those in other depression states. IFN-α stimulates indoleamine-2,3 dioxygenase-1, activating the kynurenine pathway with reduced formation of the neurotransmitters serotonin and dopamine, excessive formation of the NMDA agonist quinolinic acid, and reduced formation of the NMDA antagonist kynurenic acid. In addition, IFN-α disturbs neurotrophic signaling and impedes neurite outgrowth, synaptic plasticity, endogenous neurogenesis and neuronal survival. Consequently, IFN-α-related depression may represent a model for the neurodegenerative changes that are noticed in late-life major depression. Indeed, the observation that brain responses in IFN-α-related depression resemble idiopathic depression is supported by the existence of common genetic signatures, among which of note, a number of neuronal survival and plasticity genes have been identified. In view of the high incidence of depressive symptoms, IFN-α-related depression is an attractive model for studying links between neuronal plasticity, neurodegeneration and depression. We predict that in the latter areas new targets for anti-depressant therapies could be identified, which may deepen our understanding of idiopathic major depression.

Fluoxetine a novel anti-hepatitis C virus agent via ROS-, JNK-, and PPARβ/γ-dependent pathways

More than 20% of chronic hepatitis C (CHC) patients receiving interferon-alpha (IFN-α)-based anti-hepatitis C virus (HCV) therapy experienced significant depression, which was relieved by treatment with fluoxetine. However, whether and how fluoxetine affected directly the anti-HCV therapy remained unclear. Here, we demonstrated that fluoxetine inhibited HCV infection and blocked the production of reactive oxygen species (ROS) and lipid accumulation in Huh7.5 cells. Fluoxetine facilitated the IFN-α-mediated antiviral actions via activations of signal transducer and activator of transcription (STAT)-1 and c-Jun amino-terminal kinases (JNK). Alternatively, fluoxetine elevated peroxisome proliferator-activated receptor (PPAR) response element activity under HCV infection. The inhibitory effects of fluoxetine on HCV infection and lipid accumulation, but not production of ROS, were partially reversed by the PPAR-β, -γ, and JNK antagonists. Furthermore, fluoxetine intervention to the IFN-α-2b regimen facilitated to reduce HCV titer and alanine transaminase level for CHC patients. Therefore, fluoxetine intervention to the IFN-α-2b regimen improved the efficacy of anti-HCV treatment, which might be related to blockades of ROS generation and lipid accumulation and activation of host antiviral JNK/STAT-1 and PPARβ/γ signals.

Molecular biology of atherosclerosis

At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.