Targeting the adenosine monophosphate-activated protein kinase signalling pathway by bempedoic acid attenuates Angiotensin II-induced cardiac remodelling in renovascular hypertension in rats

The crosstalk between the renin-angiotensin system and Adenosine monophosphate-activated protein kinase (AMPK) gained significant interest due to their involvement in the pathogenesis of several cardiovascular diseases. Angiotensin II (Ang II) plays a crucial role in developing cardiac remodelling by inducing energy imbalance, inflammation, oxidative and endoplasmic reticulum stress, and transforming growth factor-β (TGF-β)-induced fibrosis. Ang II directly or through extracellular signal-regulated kinase (ERK) activation impairs AMPK signalling with well-known antioxidant, anti-inflammatory, and anti-fibrotic effects.

AIM

This study aimed to investigate the role of bempedoic acid, a novel antihyperlipidemic drug, in attenuating hypertension-induced cardiac remodelling in rats by modulating Ang II-induced damage and activating the AMPK signalling pathway.

METHOD

Sixty adult male Sprague Dawley rats were randomly allocated into the Sham control group, Hypertensive group, Captopril group (30 mg/kg), and Bempedoic acid group (30 mg/kg). Hypertension was induced by left renal artery ligation in all groups except the Sham control group. Treatment with captopril and bempedoic acid started 14 days post-surgy and lasted two weeks. Finally, Hemodynamic measurements and electrocardiographic examination were done followed by heart tissue samples collection for biochemical, histopathological, and immunohistochemical examinations.

KEY FINDINGS

Bempedoic acid preserved the cardiac function and electrocardiogram patterns. It inhibited endoplasmic reticulum stress, exhibited antioxidant activity, and increased endothelial nitric oxide synthase activity. Bempedoic acid interfered with ERK signalling pathways, including nuclear factor-κB and TGF-β, exerting anti-inflammatory and anti-fibrotic effects.

SIGNIFICANCE

These findings indicate the cardioprotective and antihypertrophic activity of bempedoic acid, which are suggested to result from energy-independent AMPK downstream signalling activation.

Camptothecin Sensitizes Hepatocellular Carcinoma Cells to Sorafenib- Induced Ferroptosis Via Suppression of Nrf2

Sorafenib is a potent inducer of ferroptosis used to manage hepatocellular carcinoma (HCC). The ferroptosis induced by sorafenib activates the p62-Keap1-Nrf2 pathway. Abnormal activation of Nrf2 reduces sorafenib's efficiency and ferroptosis action and induces sorafenib's resistance. Consequently, our study tried to study the effect of a novel combination of sorafenib and Camptothecin (CPT, Nrf2 inhibitor) to improve sorafenib's ferroptosis action and reduce sorafenib resistance in the treatment of HCC. We evaluated the efficacy of sorafenib and/or CPT using HepG2 and Huh7 cell lines. MTT assay evaluated the anti-proliferation effects. The combination index (CI) and dose reduction index (DRI) were calculated using Isobologram analysis. Malondialdehyde (MDA), total antioxidant capacity (TAC), iron concentration, glutathione peroxidase (GPX4), and glutathione reductase (GR) activity assays were used to determine the ferroptosis action of drugs. Western blot was used to investigate the expression of the implicated proteins. Bioinformatics tools were used to determine the correlation between these proteins. Finally, the HPLC technique is used to measure cellular drug uptake. Our results revealed a strong synergism between sorafenib and CPT. The synergetic combination significantly increases lipid peroxidation and iron concentration, decreases TAC, GPX4 and GR activity, and reduces the expression of both Nrf2 and SLC7A11. The downregulation of Nrf2 expression has a vital role in the reduction of resistance mediators to sorafenib against HCC cells like (p62, MT1G, and ABCG2) and improves the cellular uptake of sorafenib. The current study provided evidence that Nrf2 inhibition by CPT improves sorafenib's sensitivity and reduces sorafenib's resistance via the augmentation of sorafenib's ferroptosis action.

Effect of bempedoic acid on angiotensin-II induced hypertension and vascular tissue remodelling in renal hypertensive rats through AMPK multiple signalling pathways modulation

Angiotensin II (Ang II), the effector of the renin-angiotensin system (RAS), is a key player in the pathogenesis of chronic hypertension, accompanied by vascular tissue resistance, remodelling, and damage. Chronic activation of Ang II receptor 1 (AT-1R) impairs multiple cellular targets implicated in cellular protection and survival, including adenosine Monophosphate-activated protein kinase (AMPK) signalling. In addition, it induces oxidative damage, endoplasmic reticulum (ER) stress, and fibrotic changes in resistance vessels. Our study investigated the antihypertensive and antifibrotic effects of bempedoic acid, a first-in-class antihyperlipidemic drug that targets adenosine triphosphate-citrate lyase enzyme to inhibit cholesterol synthesis. We also studied the modulation of multiple AMPK signalling pathways by bempedoic acid in a chronic hypertension model in rats. Sixty male Sprague-Dawley rats were divided into four groups: sham group, hypertensive group, standard captopril group, and bempedoic treated group. All groups underwent left renal artery ligation except the sham group. Fourteen days post-surgery, captopril and bempedoic acid were administered with a dose of 30 mg/kg/day orally to captopril-standard and bempedoic acid-treated groups for two weeks, respectively. In mesenteric resistance arteries, bempedoic acid activated AMPK energy independently and augmented AMPK multiple cellular targets to adapt to Ang II-induced cellular stress. It exerted antioxidant activity, increased endothelial nitric oxide synthase, and reversed the ER stress. Bempedoic acid maintained vascular integrity and prevented vascular remodelling by inhibiting extracellular signal-regulated kinase (ERK)/transforming growth factor-β fibrotic pathway. These effects were reflected in the improved hemodynamic measurements.

Impedimetric Sensors for Cyclocreatine Phosphate Determination in Plasma Based on Electropolymerized Poly(o-phenylenediamine) Molecularly Imprinted Polymers

Cyclocreatine and its water-soluble derivative, cyclocreatine phosphate (CCrP), are potent cardioprotective drugs. Based on recent animal studies, CCrP, FDA-awarded Orphan Drug Designation, has a promising role in increasing the success rate of patients undergoing heart transplantation surgery by preserving donor hearts during transportation and improving the recovery of transplanted hearts in recipient patients. In addition, CCrP is under investigation as a promising treatment for creatine transporter deficiency, an X-linked inborn error resulting in a poor quality of life for both the patients and the caregiver. A newly designed molecularly imprinted polymer (MIP) material was fabricated by the anodic electropolymerization of o-phenylenediamine on screen-printed carbon electrodes and was successfully applied as an impedimetric sensor for CCrP determination to dramatically reduce the analysis time during both the clinical trial phases and drug development process. To enhance the overall performance of the proposed sensor, studies were performed to optimize the electropolymerization conditions, incubation time, and pH of the background electrolyte. Scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were used to characterize the behavior of the developed ultrathin MIP membrane. The CCrP-imprinted polymer has a high recognition affinity for the template molecule because of the formation of 3D complementary cavities within the polymer. The developed MIP impedimetric sensor had good linearity, repeatability, reproducibility, and stability within the linear concentration range of 1 × 10^-9 to 1 × 10^-7 mol/L, with a low limit of detection down to 2.47 × 10^-10 mol/L. To verify the applicability of the proposed sensor, it was used to quantify CCrP in spiked plasma samples.

Akt / GSK3β / Nrf2 / HO-1 pathway activation by flurbiprofen protects the hippocampal neurons in a rat model of glutamate excitotoxicity

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates redox homeostasis of the cell through regulation of the antioxidant response element genes transcription. Nrf2 also regulates the antiapoptotic Bcl-2 gene. Nrf2 degradation and nuclear translocation is regulated by upstream kinases Akt and GSK3β. Glutamate excitotoxicity is a process of neuronal cells death due to excessive activation of glutamate receptors. Glutamate excitotoxicity participates in the pathophysiology of several acute and chronic neurological conditions. In addition, glutamate excitotoxicity interrupts the PI3K/Akt prosurvival pathway so GSK3β remains active. Active GSK3β increases Nrf2 degradation, decreases Nrf2 nuclear translocation and increases Nrf2 nuclear export which decreases the ARE genes transcription such as, SOD, GSH synthesis enzyme and HO-1. Also, Bcl-2 transcription decreases. Flurbiprofen is a COX inhibitor. Previous studies showed that it has a neuroprotective effect in neurodegeneration and in focal cerebral ischemia/reperfusion model. In our research we aimed to test the hypothesis that flurbiprofen may have a neuroprotective effect in a rat model of glutamate-induced excitotoxicity and this neuroprotection may occur through modulation of (Akt/GSK3β/Nrf2/HO-1) pathway. Rats were divided into 4 groups; control, MSG (2.5 g/Kg, i.p), low dose FB (5 mg/kg, i.p) and high dose FB (10 mg/kg, i.p). We found that low and high doses FB decreased COX-2, PGE₂, NO and MDA and increased SOD and GSH in brain compared to MSG group. High dose was more effective than low dose. Western blotting analysis in hippocampus tissue showed that high dose FB increased p-Akt, p-GSK3β, nuclear Nrf2 and HO-1 and decreased cytosolic Nrf2 level in comparison with MSG group. Immunohistochemical analysis in hippocampus and cerebral cortex showed that high dose FB increased Bcl-2 and decreased Bax compared to MSG group. In addition, FB increased the number of intact neurons in hippocampus areas and cerebral cortex neurons and showed an anxiolytic-like action in OF and EPM tests. These findings suggest that FB has a neuroprotective effect in glutamate-induced excitotoxicity model through reduction of the glutamate excitotoxicity damage and activation of the survival pathway. These may occur due to modulation the survival pathway (Akt/GSK3β/Nrf2/HO-1) and inhibition of COX-2.

The novel SOD mimetic GC4419 increases cancer cell killing with sensitization to ionizing radiation while protecting normal cells

While radiotherapy is a widely used treatment for many types of human cancer, problems of radio-resistance and side effects remain. Side effects induced by ionizing radiation (IR) arise primarily from its propensity to trigger inflammation and oxidative stress with damage of normal cells and tissues near the treatment area. The highly potent superoxide dismutase mimetic, GC4419 (Galera Therapeutics), rapidly enters cells and is highly effective in dismutating superoxide (O₂^•-). We performed studies to assess the potency of GC4419 in cancer killing and radio-sensitization in human lung cancer cells and normal immortalized lung cells. Treatment with GC4419 did not alter the radical generation during IR, primarily hydroxyl radical (^.OH); however, it quenched the increased levels of O₂^•- detected in the cancer cells before and following IR. GC4419 triggered cancer cell death and inhibited cancer cell proliferation with no adverse effect on normal cells. Combination of GC4419 with IR augmented the cytotoxic effects of IR on cancer cells compared to monotherapy, while protecting normal cells from IR-induced cell death. DNA fragmentation and caspase-3 activity assays showed that combination of GC4419 with IR enhances cancer cell apoptosis. Moreover, GC4419 increased IR-induced Bax levels with decreased Bcl-2 and elevated Bax/Bcl-2 ratio following treatment. GC4419 increased TrxR activity in the normal cells but decreased activity in cancer cells, conferring increased cancer cell sensitivity to oxidative stress. In conclusion, GC4419 increases the cytotoxic and pro-apoptotic activity of IR in lung cancer cells while decreasing injury in normal cells.

Synthesis, Molecular Modelling and Biological Evaluation of Novel Pyrimidine Derivatives as Anti-inflammatory Agents

Aim: As part of ongoing studies in developing new anti-inflammatory agents, 2-thioxo-1,2,3,4-tetrahydropyrimidine derivative 1 was synthesized by direct Biginelli condensation and used for the synthesis of novel series of  pyrimidin-2-thione derivatives  (2a-d to 7a-b). Materials and Methods: All compounds were examined for their anti-inflammatory activity using the carrageenan-induced rat paw edema assay in comparison to ibuprofen, as a reference drug. Molecular docking studies were carried out using SYBLYL-X v.2.1 software. Study Design: A series of pyrimidine derivatives were synthesized by a simple and available method leads to a molecule of promising anti-inflammatory activity, the docking studies show good agreement with anti-inflammatory results. Future researches are recommended to assure the importance of these new derivatives for various applications. Place and Duration of Study: Pharmaceutical Organic Chemistry Department and Pharmacology and Toxicology Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt, between February 2018 and March 2019. Results: Compounds showed 61 to 86% anti-inflammatory activity where-as ibuprofen showed 69% activity. Compounds 2a, 2b, 2c, 2d, 3a, 3b, 3c, 3d, 7a, 7b induced strong anti-inflammatory activity, comparable with that of ibuprofen, they showed significantly difference at 4h post-carrageenan. Compound 3c (86%) showed the best result of edema inhibition in rats. Moreover, compounds 1, 2c and 3c were subjected to in vitro enzyme assay investigations against COX-1 and COX-2. All tested compounds showed higher potency towards COX-2 over COX-1. Compound 3c realized higher potency towards COX-2 (IC50= 0.046 μM) than compounds 1(IC50= 0.21 μM) and 2c (IC50=0.11 μM) as well as ibuprofen (IC50= 43.628 μM). Structure-activity relationship (SAR) has been discussed. Conclusion: A series of pyrimidine derivatives were synthesized by a simple and available method gave a molecule of promising anti-inflammatory activity, the docking studies showed good agreement with anti-inflammatory results.

Lixisenatide Reduced Damage in Hippocampus CA1 Neurons in a Rat Model of Cerebral Ischemia-Reperfusion Possibly Via the ERK/P38 Signaling Pathway

Glucagon-like peptide-1 (GLP-1) is a gut-derived peptide that has various physiological actions. One of its main actions is the regulation of blood glucose level when it is elevated as it potentiates insulin release. It is also known that GLP-1 protects neurons from damage caused by neurodegenerative diseases. Lixisenatide is one of the GLP-1 analogues that has a strong affinity to the GLP-1 receptor. Experimental animal studies have shown that it holds a neuroprotective effect in Parkinson, myocardial, and cerebral ischemic disease animal models. The beneficial effect of lixisenatide on the brain after cerebral ischemia-reperfusion (I/R) is not clarified yet; thus, it needs further explanatory studies. Our research is the first to study the effect of lixisenatide on myeloperoxidase (MPO) and toll-like receptors (TLRs)/mitogen-activated protein kinase (MAPK) pathway in a rat model of cerebral I/R. Lixisenatide with 2 doses 0.7 and 7 nmol/kg was given intraperitoneal in 2 different groups for 14 days; then, the bilateral common carotid artery was occluded for 1 h followed by reperfusion for 1 h. Examination of hippocampus CA1 neurons by Nissl stain showed that the number of intact neurons was elevated in the lixisenatide-treated group related to the control group (I/R group). Lixisenatide exhibited neuroprotection action possibly via downregulation of MPO, TLR2/4, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and pP38 and upregulation of phosphorylated extracellular signal-regulated kinase (pERK1/2); thus, this study gives possible link between lixisenatide and TLR/MAPK pathway following cerebral I/R and supports the use of lixisenatide for neuroprotection against stroke.

ERK activation by zeranol has neuroprotective effect in cerebral ischemia reperfusion

AIMS

Incidence of stroke increases in postmenopausal women with dangerous consequences. In this study we used zeranol to protect ovariectomized (OVX) rats against cerebral I/R damage and our target is to identify the mechanism of its protection, in addition to investigating whether this mechanism inhibits inflammation (by preventing glial cell activation) and apoptosis.

MAIN METHODS

First 18 ovariectomized rats were allocated into 3 groups: I/R group, zeranol+ I/R group and U0126, MEK1/2 inhibitor + zeranol+ I/R group. After 24 h reperfusion, protein expression of total extracellular signal-regulated protein kinase (t-ERK1/2), phosphorylated extracellular signal-regulated protein kinase (p-ERK1/2), Bcl-2, and Bax were quantified. Second 36 female rats were allocated into 3 groups: sham group, I/R group (after ovariectomy by 7 weeks, rats exposed to cerebral I/R) and zeranol group (after ovariectomy by 2 weeks, rats received zeranol for 5 weeks). After 24 h of reperfusion, the following parameters were measured; total nitrate/nitrite, interleukin-10, myeloperoxidase, caspase-3, and finally immunohistochemistry analysis of glial fibrillary acidic protein, cyclooxygenase-2 in cortex and hippocampus (CA1) regions were performed.

KEY FINDINGS

U-0126 administration reversed the neuroprotective effect induced by zeranol through decreasing ratio of p-ERK1/2:ERK1/2 and Bcl-2/Bax in brain tissue. Activation of ERK signaling pathway by zeranol caused reduction in brain apoptosis and inflammation.

SIGNIFICANCE

Zeranol showed protective effect in OVX rats that were exposed to cerebral I/R by activation of ERK signaling pathway which was blocked by U0126. This protective effect in turns led to decrease inflammation and apoptosis.

The protective effect of zeranol in cerebral ischemia reperfusion via p-CREB overexpression

AIMS

Cerebral ischemia reperfusion (I/R) is a neurovascular disease leading to cerebral damage. It was found that postmenopausal women are liable to more dangerous effects than men at same age in stroke. The objective of this study is to investigate the neuroprotective effect of zeranol against cerebral ischemia reperfusion in ovariectomized rats.

MAIN METHODS

36 female wistar rats divided in to 3 groups: sham group, I/R group (where I/R was induced 7 weeks after ovariectomy), zeranol group (0.5 mg/kg every 3 days for 5 weeks before I/R). Cerebral ischemia reperfusion (I/R) was performed by bilateral common carotid artery occlusion then de-ligated to restore blood flow. After 24 h of reperfusion, rats performed cylinder test to evaluate behavioral dysfunction followed by decapitation. Brain tissues were collected for biochemical measures such as oxidative stress marker malondialdehyde, antioxidant markers reduced glutathione, inflammatory markers (interleukin-1 beta, tumor necrosis factor alpha, and inducible nitric oxide synthase), matrix metalloproteinase-9, adenosine triphosphate, brain derived neurotrophic factor, glucose transporter-3, phosphorylated c-AMP response element binding protein and finally nissl staining for histopathological examination.

KEY FINDINGS

The zeranol administered group showed a reversal of neuronal damage caused by ischemia evidenced by the decrease in MDA, IL-1β, TNF-α, and MMP-9 levels, increase GSH, and ATP levels, decrease expression of iNOS in both regions cortex and hippocampus, increase protein level of p-CREB, GLUT-3 and BDNF, increase number of intact neuron cells in both regions and attenuated histological changes in both cortex and hippocampus regions.

SIGNIFICANCE

Zeranol has neuroprotective potential against cerebral ischemia reperfusion in ovariectomized rats.

Pyrrolopyrazoles: Synthesis, Evaluation and Pharmacological Screening as Antidepressant Agents

BACKGROUND

Pyrroles and fused pyrroles are of great interest as biologically active compounds, among these activities; antidepressant activity is of special concern.

OBJECTIVE

Synthesis of a series of pyrrolopyrazoles and their pyrimidine derivatives and their characterization using spectral data to be monitored for antidepressant activity using behavioral techniques.

METHODS

A control group was administered the vehicle i.p., positive control group received fluoxetine as standard and all other groups were administered the tested compounds. The groups were subjected to tail suspension test (TST) to determine the antidepressant activity compared with fluoxetine as a standard drug. The compounds exhibiting antidepressant activity were then used to analyze changes in serotonin (5HT) level in the brain of albino mice.

RESULTS

TST results showed that both pyrazoles and pyrazolopyrimidines derivatives exhibit promising anti-depressant activity.

CONCLUSION

Compounds [pyrazoles & pyrazlopyrimidines] showed promising antidepressant activity possibly mediated by the increased levels of 5HT.

Evaluation of novel pyrrolopyrimidine derivatives as antiviral against gastroenteric viral infections

Viral gastroenteritis is a major global public-health threat. All age groups are susceptible for this infection, but its most serious consequences affect children. Rotavirus, Coxsackievirus and Adenovirus are the most common viruses that cause gastroenteritis. Herein, we synthesized novel pyrrole, pyrrolo[2,3‑d]pyrimidine and pyrrolo[3,2‑e][1,2,4]triazolo[4,3‑c]pyrimidine derivatives. The non-toxic doses of these compounds were determined using BGM cell lines. We examined all the new compounds for their anti-viral activities against Rotavirus Wa strain and Coxsackievirus B4. Compounds 2a, 2d, 5a, 5c, 5d, 7b, 7j, 7n, 14b, 14c, 14e and 14f exhibited significant antiviral activity. We interpreted the action of these compounds using molecular docking against the homology models of viral polymerase enzymes of these viruses. RMSD value of 5d/Coxsackievirus was higher than the RMSD value for 5d/rotavirus and hence better as a stability parameter, which can be correlated to the biological activity.

Dimethyl fumarate interferes with MyD88-dependent toll-like receptor signalling pathway in isoproterenol-induced cardiac hypertrophy model

Objectives

To investigate the effect of dimethyl fumarate (DMF) on Toll-like receptor (TLR) signalling pathway in isoproterenol (ISO)-induced cardiac hypertrophy in rats.

Methods

Sixty adult male Sprague-Dawley rats were randomly allocated into three groups. group I: rats received the vehicles only; group II: rats were treated with ISO (5 mg/kg per day S.C.) to induce cardiac hypertrophy for 7 days; and group III: rats were given DMF (25 mg/kg per 12 h P.O.) for 28 days, and at the last 7 days, they were treated with ISO (5 mg/kg per day S.C.).

Key findings

Pretreatment with DMF decreased heart-to-body weight ratio, heart rate and blood pressure and improved the electrocardiographic patterns when compared with ISO group. DMF exhibited cardioprotective effect as evidenced by the reduction in cardiac troponin I, creatine kinase-MB and atrial natriuretic peptide levels. Moreover, DMF alleviated the changed oxidative stress and inflammatory biochemical markers through its anti-inflammatory and antioxidant effects. DMF interfered with TLR signalling pathway, evidenced by decreased levels of the TLR adaptor protein MyD88 and p-ERK1/2 and increased p-Akt level.

Conclusions

Dimethyl fumarate exerted cardioprotective effect against ISO-induced cardiac hypertrophy. This effect is suggested to be through interfering with TLR signalling pathway.

Neuroprotective effect of agmatine (decarboxylated l-arginine) against oxidative stress and neuroinflammation in rotenone model of Parkinson's disease

Parkinson's disease (PD) is the second most common age-related neurodegenerative disease after Alzheimer's disease, characterized by loss of dopaminergic neurons in substantia nigra pars compacta, accompanied by motor and nonmotor symptoms. The neuropathological hallmarks of PD are well reported, but the etiology of the disease is still undefined; several studies assume that oxidative stress, mitochondrial defects, and neuroinflammation play vital roles in the progress of the disease. The current study was established to investigate the neuroprotective effect of agmatine on a rotenone (ROT)-induced experimental model of PD. Adult male Sprague Dawley rats were subcutaneously injected with ROT at a dose of 2 mg/kg body weight for 35 days. Agmatine was injected intraperitoneally at 50 and 100 mg/kg body weight, 1 h prior to ROT administration. ROT-treated rats that received agmatine showed better performance on beam walking and an elevated number of rears within the cylinder test. In addition, agmatine reduced midbrain malondialdehyde as an indication of lipid peroxidation, pro-inflammatory cytokines including tumor necrosis factor alpha and interleukin-1β, and glial fibrillary acidic protein. Moreover, agmatine was responsible for preventing loss of tyrosine hydroxylase-positive neurons. In conclusion, our study showed that agmatine possesses a dose-dependent neuroprotective effect through its antioxidant and anti-inflammatory activities. These findings need further clinical investigations of agmatine as a promising neuroprotective agent for the future treatment of PD.

Protective effects of thymoquinone on D-galactose and aluminum chloride induced neurotoxicity in rats: biochemical, histological and behavioral changes

OBJECTIVES

Thymoquinone (TQ), the main active ingredient in Nigella sativa oil, exhibits various bioactivities. This study aimed to investigate the effect of TQ on neurobehavioral and neuropathological alterations induced by aluminum trichloride (AlCl₃) and D-galactose (D-gal)-in male rats and to explore the related mechanisms.

METHODS

D-gal (60 mg/kg day) and AlCl₃ (10 mg/kg day) were given intraperitoneally (i.p.) once daily for 42 days and after 4 weeks TQ was concomitantly administered intragastrically (i.g.) (20 mg/kg/day) once daily for 14 days. Then, memory function was evaluated by Morris water maze test (MWM). Superoxide dismutase (SOD), Total antioxidant capacity (TAC), Acetylcholinesterase (AChE) activities, and malondialdehyde (MDA), nitric oxide (NO), brain-derived neurotrophic factor (BDNF), and B-cell lymphoma-2 (Bcl-2) levels in whole brain were assessed with the biochemical technique. Tumor necrosis factor-alpha (TNF-α) and Acetylcholine (ACh) were also assessed using an immunohistochemical technique.

RESULTS

Administration of TQ significantly improved cognition. In addition, TQ significantly increased SOD and TAC and decreased AChE activities. It also decreased MDA and NO levels as well as TNF-α immunoreactivity and increased BDNF and Bcl-2 levels as well as ACh immunoreactivity.

DISCUSSION

Our results indicate that TQ prevents D-gal/AlCl₃-induced cognitive decline by enhancing cholinergic function and synaptic plasticity as well as attenuation of oxidative damage, neuronal apoptosis, and neuroinflammation. These results indicate that TQ holds potential for neuroprotection and may be a promising approach for the treatment of neurodegenerative disorders.

Thymoquinone alleviates the experimentally induced Alzheimer’s disease inflammation by modulation of TLRs signaling

Alzheimer’s disease (AD) is characterized by a robust inflammatory response elicited by the accumulation and deposition of amyloid-β (Aβ) within the brain. Aβ induces detrimental inflammatory responses through toll-like receptors (TLRs) signaling pathway. Thymoquinone (TQ), the main active constituent of Nigella sativa oil, has been reported by several previous studies for its potent anti-inflammatory effect. The aim of this study is to elucidate the effect of TQ in improving learning and memory, using a rat model of AD induced by a combination of aluminum chloride (AlCl3) and d-galactose (d-Gal). TQ was administered orally at doses of 10, 20, and 40 mg/kg/day for 14 days after AD induction. Memory functions were assessed using the step through passive avoidance test. Amyloid plaques were shown to be present using hematoxylin and eosin staining. Tumor necrosis factor-alpha (TNF-α) and Interleukin-1beta (IL-1β) levels in brain were assessed via ELISA and profiling TLR-2, TLR-4, myeloid differential factor 88, toll–interleukin-1 receptor domain-containing adapter-inducing interferon-β, interferon regulatory factor 3 (IRF-3), and nuclear factor-κB (NF-κB) expressions via real-time polymerase chain reaction. TQ improved AD rat cognitive decline, decreased Aβ formation and accumulation, significantly decreased TNF-α and IL-1β at all levels of doses and significantly downregulated the expression of TLRs pathway components as well as their downstream effectors NF-κB and IRF-3 mRNAs at all levels of doses ( p < 0.05). We concluded that TQ reduced the inflammation induced by d-Gal/AlCl3 combination. It is therefore reasonable to assign the anti-inflammatory responses to the modulation of TLRs pathway.

Algorithms for Argumentation Semantics: Labeling Attacks as a Generalization of Labeling Arguments

A Dung argumentation framework (AF) is a pair (A,R): A is a set of abstract arguments and R ⊆ A×A is a binary relation, so-called the attack relation, for capturing the conflicting arguments. Labeling based algorithms for enumerating extensions (i.e. sets of acceptable arguments) have been set out such that arguments (i.e. elements of A) are the only subject for labeling. In this paper we present implemented algorithms for listing extensions by labeling attacks (i.e. elements of R) along with arguments. Specifically, these algorithms are concerned with enumerating all extensions of an AF under a number of argumentation semantics: preferred, stable, complete, semi stable, stage, ideal and grounded. Our algorithms have impact, in particular, on enumerating extensions of AF-extended models that allow attacks on attacks. To demonstrate this impact, we instantiate our algorithms for an example of such models: namely argumentation frameworks with recursive attacks (AFRA), thereby we end up with unified algorithms that enumerate extensions of any AF/AFRA.

Quantifying exocytosis by combination of membrane capacitance measurements and total internal reflection fluorescence microscopy in chromaffin cells

Total internal reflection fluorescence microscopy (TIRF-Microscopy) allows the observation of individual secretory vesicles in real-time during exocytosis. In contrast to electrophysiological methods, such as membrane capacitance recording or carbon fiber amperometry, TIRF-Microscopy also enables the observation of vesicles as they reside close to the plasma membrane prior to fusion. However, TIRF-Microscopy is limited to the visualization of vesicles that are located near the membrane attached to the glass coverslip on which the cell grows. This has raised concerns as to whether exocytosis measured with TIRF-Microscopy is comparable to global secretion of the cell measured with membrane capacitance recording. Here we address this concern by combining TIRF-Microscopy and membrane capacitance recording to quantify exocytosis from adrenal chromaffin cells. We found that secretion measured with TIRF-Microscopy is representative of the overall secretion of the cells, thereby validating for the first time the TIRF method as a measure of secretion. Furthermore, the combination of these two techniques provides a new tool for investigating the molecular mechanism of synaptic transmission with combined electrophysiological and imaging techniques.

Primed vesicles can be distinguished from docked vesicles by analyzing their mobility

Neurotransmitters are released from nerve terminals and neuroendocrine cells by calcium-dependent exocytosis of vesicles. Before fusion, vesicles are docked to the plasma membrane and rendered release competent through a process called priming. Electrophysiological methods such as membrane capacitance measurements and carbon fiber amperometry accurately measure the fusion step of exocytosis with high time resolution but provide only indirect information about priming and docking. Total internal reflection fluorescence microscopy (TIRFM) enables the real-time visualization of vesicles, near the plasma membrane, as they undergo changes from one molecular state to the other. We devised a new method to analyze the mobility of vesicles, which not only allowed us to classify the movement of vesicles in three different categories but also to monitor dynamic changes in the mobility of vesicles over time. We selectively enhanced priming by treating bovine chromaffin cells with phorbol myristate acetate (PMA) or by overexpressing Munc13-1 (mammalian Unc) and analyzed the mobility of large dense-core vesicles. We demonstrate that nearly immobile vesicles represent primed vesicles because the pool of vesicles displaying this type of mobility was significantly increased after PMA treatment and Munc13-1 overexpression and decreased during tetanus toxin expression. Moreover, we showed that the movement of docked but unprimed vesicles is restricted to a confined region of approximately 220 nm diameter. Finally, a small third population of undocked vesicles showed a directed and probably active type of mobility. For the first time, we can thus distinguish the molecular state of vesicles in TIRFM by their mobility.