The inhibition of transforming growth factor beta-activated kinase 1 contributed to neuroprotection via inflammatory reaction in pilocarpine-induced rats with epilepsy

Pirfenidone regulates seizures through the HMGB1/TLR4 axis to improve cognitive functions and modulate oxidative stress and neurotransmitters in PTZ-induced kindling in mice

Background

Epilepsy is a neurological disorder characterized by recurrent seizures due to abnormal electrical activity in the brain. Pirfenidone, an antifibrotic drug, has shown anti-inflammatory and antioxidant properties in various disease models, including neurological conditions. However, its potential anticonvulsant effects have not been thoroughly explored. This study aims to evaluate the anticonvulsant potential of pirfenidone in a pentylenetetrazol-induced kindling model of epilepsy, focusing on its effect on seizure activity, cognition, antioxidant profiles, inflammatory markers, neurotransmitter balance, liver enzyme levels, and histopathological changes.

Methods

Healthy male Swiss albino mice were subjected to an acute Increasing Current Electroshock test and chronic pentylenetetrazol-kindling model. Pirfenidone was administered at doses of 100, 200, and 300 mg/kg, orally, with sodium valproate as a standard drug. Seizure severity and cognitive function were assessed in the pentylenetetrazol-kindling model, along with biochemical assays that evaluated antioxidant enzymes, inflammatory markers, neurotransmitter levels, and liver enzyme levels. Histopathological changes were also assessed in the hippocampus and cortex of experimental mice.

Results

Pirfenidone at 200 mg/kg and 300 mg/kg significantly increased Seizure Threshold Current in the Increasing Current Electroshock test, indicating a protective effect against seizures. In the pentylenetetrazol-kindling model, pirfenidone delayed seizure onset and reduced severity, with the 300 mg/kg dose showing the strongest impact. Pirfenidone also demonstrated significant improvements in cognitive function, as evidenced by enhanced performance in passive avoidance and elevated plus maze tests. Antioxidant profiles showed increased levels of superoxide dismutase, catalase, and reduced glutathione, with a corresponding reduction in malondialdehyde and acetylcholinesterase levels. Pirfenidone significantly reduced pro-inflammatory cytokines including interleukin-6, interleukin-1β, transforming growth factor-β, tumor necrosis factor- α, high-mobility group box-1, and toll-like receptor-4, elevated gamma-aminobutyric acid, decreased glutamate levels, modulated aspartate aminotransferase and alanine aminotransferase levels. Histopathological analysis revealed that pirfenidone ameliorated cellular disintegration and neuronal damage in the hippocampus and cortex.

Conclusion

Pirfenidone shows potential as an anticonvulsant, anti-inflammatory, hepatoprotective, and neuroprotective agent, with additional benefits in improving cognition and oxidative stress profiles in epilepsy treatment. Further studies are required to explore its long-term safety and efficacy.

MyD88-mediated signaling is critical for the generation of seizure responses and cognitive impairment in a model of anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

We previously demonstrated that interleukin-1 receptor-mediated immune activation contributes to seizure severity and memory loss in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. In the present study, we assessed the role of the myeloid differentiation primary response gene 88 (MyD88), an adaptor protein in Toll-like receptor signaling, in the key phenotypic characteristics of anti-NMDAR encephalitis.

METHODS

Monoclonal anti-NMDAR antibodies or control antibodies were infused into the lateral ventricle of MyD88 knockout mice (MyD88-/-) and control C56BL/6J mice (wild type [WT]) via osmotic minipumps for 2 weeks. Seizure responses were measured by electroencephalography. Upon completion of the infusion, the motor, anxiety, and memory functions of the mice were assessed. Astrocytic (glial fibrillary acidic protein [GFAP]) and microglial (ionized calcium-binding adaptor molecule 1 [Iba-1]) activation and transcriptional activation for the principal inflammatory mediators involved in seizures were determined using immunohistochemistry and quantitative real-time polymerase chain reaction, respectively.

RESULTS

As shown before, 80% of WT mice infused with anti-NMDAR antibodies (n = 10) developed seizures (median = 11, interquartile range [IQR] = 3-25 in 2 weeks). In contrast, only three of 14 MyD88-/- mice (21.4%) had seizures (0, IQR = 0-.25, p = .01). The WT mice treated with antibodies also developed memory loss in the novel object recognition test, whereas such memory deficits were not apparent in MyD88-/- mice treated with anti-NMDAR antibodies (p = .03) or control antibodies (p = .04). Furthermore, in contrast to the WT mice exposed to anti-NMDAR antibodies, the MyD88-/- mice had a significantly lower induction of chemokine (C-C motif) ligand 2 (CCL2) in the hippocampus (p = .0001, Sidak tests). There were no significant changes in the expression of GFAP and Iba-1 in the MyD88-/- mice treated with anti-NMDAR or control antibodies.

SIGNIFICANCE

These findings suggest that MyD88-mediated signaling contributes to the seizure and memory phenotype in anti-NMDAR encephalitis and that CCL2 activation may participate in the expression of these features. The removal of MyD88 inflammation may be protective and therapeutically relevant.

TGF-β Activated Kinase 1 (TAK1) Is Activated in Microglia After Experimental Epilepsy and Contributes to Epileptogenesis

Increasing evidence suggests that inflammation promotes epileptogenesis. TAK1 is a central enzyme in the upstream pathway of NF-κB and is known to play a central role in promoting neuroinflammation in neurodegenerative diseases. Here, we investigated the cellular role of TAK1 in experimental epilepsy. C57Bl6 and transgenic mice with inducible and microglia-specific deletion of Tak1 (Cx3cr1^CreER:Tak1^fl/fl) were subjected to the unilateral intracortical kainate mouse model of temporal lobe epilepsy (TLE). Immunohistochemical staining was performed to quantify different cell populations. The epileptic activity was monitored by continuous telemetric electroencephalogram (EEG) recordings over a period of 4 weeks. The results show that TAK1 was activated predominantly in microglia at an early stage of kainate-induced epileptogenesis. Tak1 deletion in microglia resulted in reduced hippocampal reactive microgliosis and a significant decrease in chronic epileptic activity. Overall, our data suggest that TAK1-dependent microglial activation contributes to the pathogenesis of chronic epilepsy.

α-Linolenic Acid Inhibits RANKL-Induced Osteoclastogenesis In Vitro and Prevents Inflammation In Vivo

Inflammation is an important risk factor for bone-destroying diseases. Our preliminary research found that Zanthoxylum bungeanum seed oil (ZBSO) is abundant in unsaturated fatty acids and could inhibit osteoclastogenesis in receptor activator of nuclear factor κB ligand (RANKL)-induced RAW264.7 cells. However, the key constituents in ZBSO in the prevention of osteoclastogenesis and its possible mechanism related to inflammation are still unclear. Therefore, in this study, oleic acid (OA), linoleic acid (LA), palmitoleic acid (PLA), and alpha-linolenic acid (ALA) in ZBSO, havingthe strongest effect on RANKL-induced osteoclastogenesis, were selected by a tartrate-resistant acid phosphatase (TRAP) staining method. Furthermore, the effects of the selected fatty acids on anti-inflammation and anti-osteoclastogenesis in vitro and in vivo were assessed using RT-qPCR. Among the four major unsaturated fatty acids we tested, ALA displayed the strongest inhibitory effect on osteoclastogenesis. The increased expression of free fatty acid receptor 4 (FFAR4) and β-arrestin2 (βarr2), as well as the decreased expression of nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), nuclear factor of activated T-cells c1 (NFATc1), and tartrate-resistant acid phosphatase (TRAP) in RAW264.7 cells after ALA treatment were observed. Moreover, in ovariectomized osteoporotic rats with ALA preventive intervention, we found that the expression of TNF-α, interleukin-6 (IL-6), interleukin-1β (IL-1β), NFATc1, and TRAP were decreased, while with the ALA therapeutic intervention, downregulated expression of NF-κB, NFATc1, TRAP, and transforming growth factor beta-activated kinase 1 (TAK1) were noticed. These results indicate that ALA, as the major unsaturated fatty acid in ZBSO, could inhibit RANKL-induced osteoclastogenesis via the FFAR4/βarr2 signaling pathway and could prevent inflammation, suggesting that ZBSO may be a promising potential natural product of unsaturated fatty acids and a dietary supplement for the prevention of osteoclastogenesis and inflammatory diseases.

Role of circulating miR 194-5p, miR 106b, and miR 146a as potential biomarkers for epilepsy: a case-control study

Background

Epilepsy is a chronic neurological disease. A suitable biomarker for epilepsy diagnosis remains lacking. MicroRNAs (miRNAs) were pronounced as promising biomarkers for epileptogenesis.

Objectives

To analyze the expression levels of miR 194-5p, miR 106b, and miR 146a in Egyptian epileptic patients compared to control subjects and to detect their correlation to clinical characteristics.

Subjects and methods

We evaluated the expression levels of miR 106b, miR 146a, and miR 194-5p using real-time quantitative polymerase chain reaction (qRT-PCR) in 50 subjects: 15 patients with idiopathic generalized epilepsy, 15 patients with focal epilepsy (3 idiopathic and 12 cryptogenic), and 20 healthy controls.

Results

miR 106b and miR 194-5p were upregulated in the generalized epilepsy group compared to control; miR 194-5p was significantly downregulated in the focal epilepsy group compared to the generalized epilepsy group and control (p ˂ 0.05). miR 194-5p was negatively correlated to disease duration in patients with focal epilepsy; the three microRNAs were positively correlated to each other (p ˂ 0.05).

Conclusion

Serum miR 194-5P and miR 106b can be used as potential non-invasive biomarkers in the evaluation of idiopathic generalized epilepsy.

Differential expression of miR-34a, 451, 1260, 1275 and 1298 in the neocortex of patients with mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy (mTLE) is the most common epilepsy syndrome which will eventually become pharmacologically intractable partial-onset seizures. Regulation of gene expression is an important process in the development of this pathology where microRNAs (miRs) are involved. The role of miRs has been widely studied in the hippocampus of rodents and patients. However, little is known about its differential expression in other brain regions such as the neocortex. The temporal neocortex plays a major role in the generation and propagation of seizures and in synaptic disruption, impairing the excitatory and inhibitory balance. Therefore, we assessed the expression of miR-146a, 34a, 1260, 1275, 1298, 451, 132 and 142-3p in the neocortex of 12 patients with mTLE and compared them with miRs expression found in 10 control samples. We noted a significant decrease in the expression of miR-34a and 1298 in patients with mTLE and a -1.49 to -7.0 fold change respectively compared with controls. Conversely, we observed a significant increase in the expression of miR-451, 1260 and 1275 in patients with a 25.67, 4.09 and a 7.07 fold change respectively compared to controls. Using Pearson correlation, we explored the association between the clinical features of mTLE patients and controls with miRs expression. In the control group we found a significant correlation only with age and miR-146a expression (r = 0.733). The analysis of mTLE patients showed a negative correlation between expression of miR-1260 (r = -0.666) and miR-1298 (r = -0.651) and age. Furthermore, we found a positive correlation between miR-146a expression with seizure frequency (r = 0.803) and a positive correlation between miR-146a and 451 expression with number of antiepileptic drugs used for presurgical treatment (r = 0.715 and 0.611 respectively), thus suggesting a positive correlation with disease severity. These miRs are associated with biological processes such as apoptosis, drug resistance, inflammation, inhibitory and excitatory synaptic transmission, axonal guidance and signaling of neurotrophins. Therefore, deepening our understanding of the targets involved in these miRs will help to elucidate the role of the neocortex in epilepsy.

Role of the Angiotensin Pathway and its Target Therapy in Epilepsy Management

Despite extensive research on epileptogenesis, there is still a need to investigate new pathways and targeted therapeutic approaches in this complex process. Inflammation, oxidative stress, neurotoxicity, neural cell death, gliosis, and blood–brain barrier (BBB) dysfunction are the most common causes of epileptogenesis. Moreover, the renin–angiotensin system (RAS) affects the brain’s physiological and pathological conditions, including epilepsy and its consequences. While there are a variety of available pharmacotherapeutic approaches, information on new pathways is in high demand and the achievement of treatment goals is greatly desired. Therefore, targeting the RAS presents an interesting opportunity to better understand this process. This has been supported by preclinical studies, primarily based on RAS enzyme, receptor-inhibition, and selective agonists, which are characterized by pleiotropic properties. Although there are some antiepileptic drugs (AEDs) that interfere with RAS, the main targeted therapy of this pathway contributes in synergy with AEDs. However, the RAS-targeted treatment alone, or in combination with AEDs, requires clinical studies to contribute to, and clarify, the evidence on epilepsy management. There is also a genetic association between RAS and epilepsy, and an involvement of pharmacogenetics in RAS, so there are possibilities for the development of new diagnostic and personalized treatments for epilepsy.