Indoleamine 2, 3-dioxygenase 1 (IDO) is responsible for the progression of the kynurenine pathway. This pathway has been implicated in the pathophysiology of inflammation-induced depression in which conventional antidepressants are not effective. It has been reported that granulocyte-macrophage stimulating factor (GM-CSF) could interfere with the induction of IDO in septic patients. We hypothesized that GM-CSF could exert antidepressant effects through IDO downregulation in a model for acute inflammation-induced depression. To produce the model, lipopolysaccharide (LPS) (0.83 mg/kg) was administered intraperitoneally to mice. It has been well documented that LPS mediates IDO overexpression through TLR4/NF-ĸB signaling. In the treatment group, mice received GM-CSF (30 μg/kg, i.p.) thirty minutes prior to LPS injection. A validated selective serotonin reuptake inhibitor, fluoxetine (30 mg/kg i.p.), was also administered to an experimental group 30 min prior to LPS. Depressive-like behaviors were evaluated based on the duration of immobility in the forced swim test. To confirm that GM-CSF interferes with IDO induction in LPS treated mice, real-time PCR was used to quantify IDO mRNA expression. Furthermore, in order to study whether GM-CSF inhibits the TLR4/NF-ĸB signaling pathway, we measured levels ofpNF-ĸB and TLR4 by western blotting. GM-CSF demonstrated significant antidepressant activity in the presence of LPS on immobility (p < .001) and latency (p = .010) times in the forced swim test. In contrast, fluoxetine did not show any antidepressant activity on either immobility (p = .918) or latency (p = .566) times. Furthermore, GM-CSF inhibited the increase in IDO mRNA (p = .032) and protein (p = .016) expression as a result of LPS administration. A similar trend was observed for TLR4 (p = .042) and pNF-ĸB (p = .026) expression as both proteins showed reduced expression levels in the GM-CSF-pretreated group compared to the untreated (LPS) group. Our results propose a promising antidepressant effect for GM-CSF possibly through the downregulation of IDO expression. This remedying effect of GM-CSF could be attributed to decreased amounts of TLR4 and active NF-ĸB in the treated mice.
3 September 2019 in Immunopharmacology and Immunotoxicology
Background: The phenomenon of ischemic stroke receives maximal attention nowadays. Many studies are designed to discover new therapies for reducing debilitating consequences of this disorder. Development of stroke-related tissue damage is due to the combination of blood flow occlusion and reperfusion phase. Inflammatory pathways participate in excess oxidative stress formation after reperfusion. Modafinil is a well-known medication prescribed for sleep disorders. Recently, several studies have focused on finding new indications for modafinil treatment. Anti-inflammatory effects of modafinil through disrupting NF-κB signaling pathway is reported previously. Downregulation of inflammatory cytokines and further oxidative damage have also been mentioned in various experiments. So far, no specific experiment had been conducted to assess the anti-inflammatory effects of modafinil on ischemic stroke. Material and methods: We evaluated outcomes of acutely administered modafinil on post-stroke behaviors and histopathological features (including apoptotic caspase-3 expressing neurons) through bilateral common carotid artery occlusion in rats. Alterations in concentrations of TNFɑ and IL-1β were assessed, together with malon di-aldehyde (MDA) to represent oxidation level. Western blotting was used to reveal the involvement of NF-κB downregulation. Considering possible alterations in blood flow and neuronal metabolism, we also assessed the effects of modafinil on cerebral glucose metabolism through PET scan. Results and discussion: Modafinil exhibited promising effects on remission of behavioral deficits and the number of degenerated neurons in ischemic hippocampus CA1 region. IL-1β and MDA levels were downregulated in treated animals. However, no significant alteration was observed in PET results and TNFɑ between treated and non-treated ischemic brains. Decreased protein levels of NF-κB was also measured in modafinil treated animals. Conclusion: Our findings demonstrate a promising therapeutic effect of modafinil for animal models of stroke.
25 August 2020 in Immunopharmacology and Immunotoxicology
Aim The purpose of the present study is to explore the anti-inflammatory potential of risperidone in acetic acid-induced rat colitis through inhibition of TLR4/NF-kB pathway Methods Acute colitis induction was done by intra-rectal administration of 2 mL of 4% diluted acetic acid solution. Two h after colitis induction, dexamethasone (2 mg/kg) as standard drugorrisperidone (2, 4 and 6 mg/kg) were administered orally to wistar rats for five consecutive days. 24 h after the last treatment, animals were sacrificed by cervical dislocation. Macroscopic and microscopic damage evaluation was done. Biochemical and ELISA methods were used to assess myeloid peroxidase (MPO) enzyme activity and tumor necrosis factor-α (TNF-α) level respectively. Moreover,immunohistochemistry (IHC) was performed to detect the expression of TLR4 and pNF-kBproteins. Results Dexamethasone (2mg/kg)orrisperidone(2, 4 and 6 mg/kg) improved acetic acid-induced macroscopic (P < 0.001) and microscopic lesions.Additionally, risperidone (2, 4 and 6 mg/kg)inhibited the activity of MPO and TNF-α (P < 0.01, P < 0.001) in the colon tissue compared to acetic acid group. Furthermore, bothdexamethasone and risperidone(2, 4 and 6 mg/kg) significantly reducedacetic acid-induced expression of TLR4and pNF-kB proteins (p < 0.05, p < 0.01, P < 0.001). Conclusion The anti-inflammatory effect of risperidoneon acetic acid-induced colitis in rats may involve inhibition of TLR4 and NF-kB signaling pathway.
15 February 2019 in Journal of Cellular Biochemistry
Depression is the most common psychiatric comorbidity of epilepsy. However, the molecular pathways underlying this association remain unclear. The NMDA receptor (NMDAR) may play a role in this association, as its downstream signaling has been shown to undergo long-term changes following excitotoxic neuronal damage. To study this pathway, we used an animal model of fluoxetine-resistant epilepsy-associated depression (EAD). We determined the molecular changes associated with the development of depressive symptoms and examined their response to various combinations of fluoxetine and a selective neuronal nitric oxide synthase inhibitor, 7-nitroindazole (NI). Depressive symptoms were determined using the forced swim test. Furthermore, expression and phosphorylation levels of markers in the ERK/CREB/ELK1/BDNF/cFOS pathway were measured to determine the molecular changes associated with these symptoms. Finally, oxidative stress markers were measured to more clearly determine the individual contributions of each treatment. While chronic fluoxetine (Flxc) and NI were ineffective alone, their combination had a statistically significant synergistic effect in reducing depressive symptoms. The development of depressive symptoms in epileptic rats was associated with the downregulation of ERK2 expression and ELK1 and CREB phosphorylation. These changes were exactly reversed upon Flxc + NI treatment, which led to increased BDNF and cFOS expression as well. Interestingly, ERK1 did not seem to play a role in these experiments. NI seemed to have augmented Flxc’s antidepressant activity by reducing oxidative stress. Our findings suggest NMDAR signaling alterations are a major contributor to EAD development and a potential target for treating conditions associated with underlying excitotoxic neuronal damage.
The Mela Rosa dei Monti Sibillini is an ancient apple variety cultivated by Romans in the foothills of the Sibillini Mountains, central Italy, showing potential as a source of nutraceuticals. The purpose of this study was to evaluate the protective effects of the hydroalcoholic extracts from the peel (APE) and pulp (APP) of this fruit in an animal model of transient global ischemia. Chemical constituents were analyzed by liquid chromatography–mass spectrometry (LC-DAD-MSn) indicating several polyphenols such as B-type procyanidins, quercetin derivatives and hydroxycinnamic acids as the main bioactive components. Acute pre-treatment of extracts (30 mg/kg, i.p.) significantly decreased the brain levels of the pro-inflammatory cytokines IL-1β (p < 0.01) and TNF-α (p < 0.001 and p < 0.01 for APE and APP, respectively), the expression of caspase-3 (p < 0.01, For APE) and MDA (p < 0.05), a lipid peroxidation biomarker in rats. Both extracts restricted the pathological changes of the brain induced by ischemic stroke in hematoxylin and eosin assay. Moreover, they improved the scores of behavioral tests in grid-walking and modified neurological severity scores (mNSS) tests. In conclusion, these results proved this ancient Italian apple is a source of nutraceuticals able to protect/prevent damage from brain ischemia.