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Fulltext Isolation and Characterization of A2-EPTX-Nsm1a, a Secretory Phospholipase A2 from Malaysian Spitting Cobra (Naja sumatrana) Venom

Abdullah NAH, Rusmili MRA, Zainal Abidin SA, Shaikh MF, Hodgson WC, Othman I

Toxins (Basel), 2021 12 02;13(12).
PMID: 34941697 DOI: 10.3390/toxins13120859

Phospholipase A2 (PLA2) toxins are one of the main toxin families found in snake venom. PLA2 toxins are associated with various detrimental effects, including neurotoxicity, myotoxicity, hemostatic disturbances, nephrotoxicity, edema, and inflammation. Although Naja sumatrana venom contains substantial quantities of PLA2 components, there is limited information on the function and activities of PLA2 toxins from the venom. In this study, a secretory PLA2 from the venom of Malaysian N. sumatrana, subsequently named A2-EPTX-Nsm1a, was isolated, purified, and characterized. A2-EPTX-Nsm1a was purified using a mass spectrometry-guided approach and multiple chromatography steps. Based on LC-MSMS, A2-EPTX-Nsm1a was found to show high sequence similarity with PLA2 from venoms of other Naja species. The PLA2 activity of A2-EPTX-Nsm1 was inhibited by 4-BPB and EDTA. A2-EPTX-Nsm1a was significantly less cytotoxic in a neuroblastoma cell line (SH-SY5Y) compared to crude venom and did not show a concentration-dependent cytotoxic activity. To our knowledge, this is the first study that characterizes and investigates the cytotoxicity of an Asp49 PLA2 isolated from Malaysian N. sumatrana venom in a human neuroblastoma cell line.
Fulltext Embelin Improves the Spatial Memory and Hippocampal Long-Term Potentiation in a Rat Model of Chronic Cerebral Hypoperfusion

Bhuvanendran S, Bakar SNS, Kumari Y, Othman I, Shaikh MF, Hassan Z

Sci Rep, 2019 10 10;9(1):14507.
PMID: 31601902 DOI: 10.1038/s41598-019-50954-y

Alzheimer's disease (AD) is the second most occurring neurological disorder after stroke and is associated with cerebral hypoperfusion, possibly contributing to cognitive impairment. In the present study, neuroprotective and anti-AD effects of embelin were evaluated in chronic cerebral hypoperfusion (CCH) rat model using permanent bilateral common carotid artery occlusion (BCCAO) method. Rats were administered with embelin at doses of 0.3, 0.6 or 1.2 mg/kg (i.p) on day 14 post-surgery and tested in Morris water maze (MWM) followed by electrophysiological recordings to access cognitive abilities and synaptic plasticity. The hippocampal brain regions were extracted for gene expression and neurotransmitters analysis. Treatment with embelin at the doses of 0.3 and 0.6 mg/kg significantly reversed the spatial memory impairment induced by CCH in rats. Embelin treatment has significantly protected synaptic plasticity impairment as assessed by hippocampal long-term potentiation (LTP) test. The mechanism of this study demonstrated that embelin treatment alleviated the decreased expression of BDNF, CREB1, APP, Mapt, SOD1 and NFκB mRNA levels caused by CCH rats. Furthermore, treatment with embelin demonstrated neuromodulatory activity by its ability to restore hippocampal neurotransmitters. Overall these data suggest that embelin improve memory and synaptic plasticity impairment in CCH rats and can be a potential drug candidate for neurodegenerative disease-related cognitive disorders.
Fulltext Acute toxicity profiling of the ethyl acetate fraction of Swietenia macrophylla seeds and in-vitro neuroprotection studies

Sayyad M, Tiang N, Kumari Y, Goh BH, Jaiswal Y, Rosli R, et al.

Saudi Pharm J, 2017 Feb;25(2):196-205.
PMID: 28344469 DOI: 10.1016/j.jsps.2016.05.002

Swietenia macrophylla (SM) is a medicinally important plant found in tropical and subtropical regions of the world. The ethyl acetate fraction of the seeds of S. macrophylla (SMEAF) is reported to exhibit potent anticancer, antitumor, anti-inflammatory and antifeedant activities. Till date, there have been no studies reported on the acute oral toxicity profile of the ethyl acetate fraction of the seeds of SM. The objective of the present study was to determine the acute toxicity of SMEAF and evaluate the in-vitro neuroprotective activity of SMEAF using primary neuronal cell cultures. In acute oral toxicity study, the SMEAF did not produce any lethal signs of morbidity and mortality. Histo-pathological findings, support the safety of SMEAF, as there were no significant changes observed in any of the parameters studied. Based on the results obtained in MTT assay, we infer that SMEAF has a significant neuroprotective effect, as it increased the cell viability and exhibited protection to the neuronal cells against TBHP induced oxidative stress. Thus, SMEAF can be suggested for use in the development of herbal drug formulations with neuroprotective potential.
Fulltext Effect of Pelargonidin isolated from Ficus benghalensis L. on phenotypic changes in zebrafish (Danio rerio) embryos

Kundap U, Jaiswal Y, Sarawade R, Williams L, Shaikh MF

Saudi Pharm J, 2017 Feb;25(2):249-257.
PMID: 28344476 DOI: 10.1016/j.jsps.2016.06.010

In the present study, the extraction and isolation of Pelargonidin, an anthocyanin compound from stem bark of Ficus benghalensis are described. The study also involves evaluation of the effect of Pelargonidin on phenotypic variations in zebra fish embryos. Extraction and isolation of Pelargonidin were carried out by employing liquid-liquid extraction technique, phytochemical tests, column chromatography, UV and FT-IR. In the zebra fish embryo model, Paclitaxel was employed as a negative control. A series of phenotypic changes in different stages of embryonic development were studied with treatment concentrations of Pelargonidin between 3.0 and 20 ppm at 0-72-hour post-fertilization (hpf). The results of our studies indicate that, after exposure of zebra fish embryos to 3.3-20 ppm concentration of Pelargonidin for 72 h, a significant reduction in aortic development occurs. At the dose level of 0.5 ppm Paclitaxel and Pelargonidin in the dose range between 3.3 and 20 ppm, the zebra fish embryos were found to have bent tail, malformed eyes and developmental delays in vasculature. Based on the results obtained, we infer that Pelargonidin can exhibit phenotypic anti-angiogenic variations in embryonic stage of fish embryos and it can be applied in future for exploration of its anti-angiogenic potential. Furthermore, Pelargonidin could serve as a candidate drug for in vivo inhibition of angiogenesis and can be applied for the treatment of neovascular diseases and tumor.
Effect of newer anti-epileptic drugs (AEDs) on the cognitive status in pentylenetetrazol induced seizures in a zebrafish model

Choo BKM, Kundap UP, Johan Arief MFB, Kumari Y, Yap JL, Wong CP, et al.

Prog Neuropsychopharmacol Biol Psychiatry, 2019 06 08;92:483-493.
PMID: 30844417 DOI: 10.1016/j.pnpbp.2019.02.014

Epilepsy is marked by seizures that are a manifestation of excessive brain activity and is symptomatically treatable by anti-epileptic drugs (AEDs). Unfortunately, the older AEDs have many side effects, with cognitive impairment being a major side effect that affects the daily lives of people with epilepsy. Thus, this study aimed to determine if newer AEDs (Zonisamide, Levetiracetam, Perampanel, Lamotrigine and Valproic Acid) also cause cognitive impairment, using a zebrafish model. Acute seizures were induced in zebrafish using pentylenetetrazol (PTZ) and cognitive function was assessed using the T-maze test of learning and memory. Neurotransmitter and gene expression levels related to epilepsy as well as learning and memory were also studied to provide a better understanding of the underlying processes. Ultimately, impaired cognitive function was seen in AED treated zebrafish, regardless of whether seizures were induced. A highly significant decrease in γ-Aminobutyric Acid (GABA) and glutamate levels was also discovered, although acetylcholine levels were more variable. The gene expression levels of Brain-Derived Neurotrophic Factor (BDNF), Neuropeptide Y (NPY) and Cyclic Adenosine Monophosphate (CAMP) Responsive Element Binding Protein 1 (CREB-1) were not found to be significantly different in AED treated zebrafish. Based on the experimental results, a decrease in brain glutamate levels due to AED treatment appears to be at least one of the major factors behind the observed cognitive impairment in the treated zebrafish.
Fulltext The anti-neuroinflammatory effects of Clinacanthus nutans leaf extract on metabolism elucidated through 1H NMR in correlation with cytokines microarray

Ahmad Azam A, Ismail IS, Kumari Y, Shaikh MF, Abas F, Shaari K

PLoS One, 2020;15(9):e0238503.
PMID: 32925968 DOI: 10.1371/journal.pone.0238503

Clinacanthus nutans (CN) (Acanthaceae) is well-known for its anti-inflammatory properties among Asian communities; however, there are currently no data specifically focused on the anti-inflammatory effects of CN on the brain tissue. Neuroinflammation is a common consequence of toxin intrusion to any part of the central nervous system (CNS). As an innate immune response, the CNS may react through both protective and/or toxic actions due to the activation of neuron cells producing pro- and/or anti-inflammatory cytokines in the brain. The unresolved activation of the inflammatory cytokines' response is associated with the pathogenesis of neurological disorders. The present study aimed to decipher the metabolic mechanism on the effects of 14 days oral treatment with CN aqueous extract in induced-lipopolysaccharides (LPS) rats through 1H NMR spectroscopic biomarker profiling of the brain tissue and the related cytokines. Based on the principal component analysis (PCA) of the nuclear magnetic resonance (NMR) spectral data, twenty-one metabolites in the brain tissue were profiled as biomarkers for the LPS (10 μL)-induced neuroinflammation following intracerebroventricular injection. Among the twenty-one biomarkers in the neuroinflammed rats, CN treatment of 1000 and 500 mg/kg BW successfully altered lactate, pyruvate, phosphorylcholine, glutamine, and α-ketoglutarate when compared to the negative control. Likewise, statistical isolinear multiple component analysis (SIMCA) showed that treatments by CN and the positive control drug, dextromethorphan (DXM, 5 mg/kg BW), have anti-neuroinflammatory potential. A moderate correlation, in the orthogonal partial least squares (OPLS) regression model, was found between the spectral metabolite profile and the cytokine levels. The current study revealed the existence of high levels of pro-inflammatory cytokines, namely IL-1α, IL-1β, and TNF-α in LPS-induced rats. Both CN dose treatments lowered IL-1β significantly better than DXM Interestingly, DXM and CN treatments both exhibited the upregulation of the anti-inflammatory cytokines IL-2 and 4. However, DXM has an advantage over CN in that the former also increased the expression of IL-10 of anti-inflammatory cytokines. In this study, a metabolomics approach was successfully applied to discover the mechanistic role of CN in controlling the neuroinflammatory conditions through the modulation of complex metabolite interactions in the rat brain.
Implication of HMGB1 signaling pathways in Amyotrophic lateral sclerosis (ALS): From molecular mechanisms to pre-clinical results

Paudel YN, Angelopoulou E, Piperi C, Othman I, Shaikh MF

Pharmacol Res, 2020 06;156:104792.
PMID: 32278047 DOI: 10.1016/j.phrs.2020.104792

Amyotrophic lateral sclerosis (ALS) is a devastating and rapidly progressing neurodegenerative disorder with no effective disease-modifying treatment up to date. The underlying molecular mechanisms of ALS are not yet completely understood. However, the critical role of the innate immune system and neuroinflammation in ALS pathogenesis has gained increased attention. High mobility group box 1 (HMGB1) is a typical damage-associated molecular pattern (DAMP) molecule, acting as a pro-inflammatory cytokine mainly through activation of its principal receptors, the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) which are crucial components of the innate immune system. HMGB1 is an endogenous ligand for both RAGE and TLR4 that mediate its biological effects. Herein, on the ground of pre-clinical findings we unravel the underlying mechanisms behind the plausible contribution of HMGB1 and its receptors (RAGE and TLR4) in the ALS pathogenesis. Furthermore, we provide an account of the therapeutic outcomes associated with inhibition/blocking of HMGB1 receptor signalling in preventing motor neuron's death and delaying disease progression in ALS experimental models. There is strong evidence that HMGB1, RAGE and TLR4 signaling axes might present potential targets against ALS, opening a novel headway in ALS research that could plausibly bridge the current treatment gap.
Role of Innate Immune Receptor TLR4 and its endogenous ligands in epileptogenesis

Paudel YN, Angelopoulou E, Akyuz E, Piperi C, Othman I, Shaikh MF

Pharmacol Res, 2020 10;160:105172.
PMID: 32871246 DOI: 10.1016/j.phrs.2020.105172

Understanding the interplay between the innate immune system, neuroinflammation, and epilepsy might offer a novel perspective in the quest of exploring new treatment strategies. Due to the complex pathology underlying epileptogenesis, no disease-modifying treatment is currently available that might prevent epilepsy after a plausible epileptogenic insult despite the advances in pre-clinical and clinical research. Neuroinflammation underlies the etiopathogenesis of epilepsy and convulsive disorders with Toll-like receptor (TLR) signal transduction being highly involved. Among TLR family members, TLR4 is an innate immune system receptor and lipopolysaccharide (LPS) sensor that has been reported to contribute to epileptogenesis by regulating neuronal excitability. Herein, we discuss available evidence on the role of TLR4 and its endogenous ligands, the high mobility group box 1 (HMGB1) protein, the heat shock proteins (HSPs) and the myeloid related protein 8 (MRP8), in epileptogenesis and post-traumatic epilepsy (PTE). Moreover, we provide an account of the promising findings of TLR4 modulation/inhibition in experimental animal models with therapeutic impact on seizures.
Fractalkine (CX3CL1) signaling and neuroinflammation in Parkinson's disease: Potential clinical and therapeutic implications

Angelopoulou E, Paudel YN, Shaikh MF, Piperi C

Pharmacol Res, 2020 08;158:104930.
PMID: 32445958 DOI: 10.1016/j.phrs.2020.104930

Neuroinflammation plays a crucial role in the pathogenesis of Parkinson's disease (PD) with the dysregulation of microglial activity being tightly linked to dopaminergic degeneration. Fractalkine (CX3CL1), a chemokine mainly expressed by neurons, can modulate microglial activity through binding to its sole G-protein-coupled receptor (CX3CR1), expressed by microglia. Fractalkine/CX3CR1 signaling is one of the most important mediators of the communication between neurons and microglia, and its emerging role in neurodegenerative disorders including PD has been increasingly recognized. Pre-clinical evidence has revealed that fractalkine signaling axis exerts dual effects on PD-related inflammation and degeneration, which greatly depend on the isoform type (soluble or membrane-bound), animal model (mice or rats, toxin- or proteinopathy-induced), route of toxin administration, time course and specific brain region (striatum, substantia nigra). Furthermore, although existing clinical evidence is scant, it has been indicated that fractalkine may be possibly associated with PD progression, paving the way for future studies investigating its biomarker potential. In this review, we discuss recent evidence on the role of fractalkine/CX3CR1 signaling axis in PD pathogenesis, aiming to shed more light on the molecular mechanisms underlying the neuroinflammation commonly associated with the disease, as well as potential clinical and therapeutic implications.
Emerging neuroprotective effect of metformin in Parkinson's disease: A molecular crosstalk

Paudel YN, Angelopoulou E, Piperi C, Shaikh MF, Othman I

Pharmacol Res, 2020 02;152:104593.
PMID: 31843673 DOI: 10.1016/j.phrs.2019.104593

Parkinson's disease (PD) is a devastating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and Lewy pathology. PD is a major concern of today's aging population and has emerged as a global health burden. Despite the rapid advances in PD research over the past decades, the gold standard therapy provides only symptomatic relief and fails to halt disease progression. Therefore, exploring novel disease-modifying therapeutic strategies is highly demanded. Metformin, which is currently used as a first-line therapy for type 2 diabetes mellitus (T2DM), has recently demonstrated to exert a neuroprotective role in several neurodegenerative disorders including PD, both in vitro and in vivo. In this review, we explore the neuroprotective potential of metformin based on emerging evidence from pre-clinical and clinical studies. Regarding the underlying molecular mechanisms, metformin has been shown to inhibit α-synuclein (SNCA) phosphorylation and aggregation, prevent mitochondrial dysfunction, attenuate oxidative stress, modulate autophagy mainly via AMP-activated protein kinase (AMPK) activation, as well as prevent neurodegeneration and neuroinflammation. Overall, the neuroprotective effects of metformin in PD pathogenesis present a novel promising therapeutic strategy that might overcome the limitations of current PD treatment.
Fulltext Animal Models of Metabolic Epilepsy and Epilepsy Associated Metabolic Dysfunction: A Systematic Review

Kundap UP, Paudel YN, Shaikh MF

Pharmaceuticals (Basel), 2020 May 26;13(6).
PMID: 32466498 DOI: 10.3390/ph13060106

Epilepsy is a serious neurological disorder affecting around 70 million people globally and is characterized by spontaneous recurrent seizures. Recent evidence indicates that dysfunction in metabolic processes can lead to the alteration of neuronal and network excitability, thereby contributing to epileptogenesis. Developing a suitable animal model that can recapitulate all the clinical phenotypes of human metabolic epilepsy (ME) is crucial yet challenging. The specific environment of many symptoms as well as the primary state of the applicable neurobiology, genetics, and lack of valid biomarkers/diagnostic tests are the key factors that hinder the process of developing a suitable animal model. The present systematic review summarizes the current state of available animal models of metabolic dysfunction associated with epileptic disorders. A systematic search was performed by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model. A range of electronic databases, including google scholar, Springer, PubMed, ScienceDirect, and Scopus, were scanned between January 2000 and April 2020. Based on the selection criteria, 23 eligible articles were chosen and are discussed in the current review. Critical analysis of the selected literature delineated several available approaches that have been modeled into metabolic epilepsy and pointed out several drawbacks associated with the currently available models. The result describes available models of metabolic dysfunction associated with epileptic disorder, such as mitochondrial respiration deficits, Lafora disease (LD) model-altered glycogen metabolism, causing epilepsy, glucose transporter 1 (GLUT1) deficiency, adiponectin responsive seizures, phospholipid dysfunction, glutaric aciduria, mitochondrial disorders, pyruvate dehydrogenase (PDH) α-subunit gene (PDHA1), pyridoxine dependent epilepsy (PDE), BCL2-associated agonist of cell death (BAD), Kcna1 knock out (KO), and long noncoding RNAs (lncRNA) cancer susceptibility candidate 2 (lncRNA CASC2). Finally, the review highlights certain focus areas that may increase the possibilities of developing more suitable animal models and underscores the importance of the rationalization of animal models and evaluation methods for studying ME. The review also suggests the pressing need of developing precise robust animal models and evaluation methods for investigating ME.
Fulltext Epilepsy-associated comorbidities among adults: A plausible therapeutic role of gut microbiota

Arulsamy A, Shaikh MF

Neurobiol Dis, 2022 Feb 01;165:105648.
PMID: 35121147 DOI: 10.1016/j.nbd.2022.105648

Epilepsy is a debilitating disorder that affects about 70 million people in the world currently. Most patients with epilepsy (PWE) often reported at least one type of comorbid disorder. These may include neuropsychiatric disorders, cognitive deficits, migraine, cardiovascular dysfunction, systemic autoimmune disorders and others. Current treatment strategies against epilepsy-associated comorbidities have been based on targeting each disorder separately with either anti-seizure medications (ASMs), anti-inflammatories or anti-depressant drugs, which have often given inconsistent and ineffective results. Gut dysbiosis may be a common pathological pathway between epilepsy and its comorbid disorders, and thus may serve as a possible intervention target. Therefore, this narrative review aimed to elucidate the potential pathological and therapeutic role of the gut microbiota in adult epilepsy-associated comorbidities. This review noticed a scarcity in the current literature on studies investigating the direct role of the gut microbiota in relation to epilepsy-associated comorbidities. Nevertheless, gut dysbiosis have been implicated in both epilepsy and its associated comorbidities, with similarities seen in the imbalance of certain gut microbiota phyla (Firmicutes), but differences seen in the mechanism of action. Current gut-related interventions such as probiotics have been consistently reported across studies to provide beneficial effects in correcting gut dysbiosis and improving various disorders, independent of epilepsy. However, whether these beneficial effects may translate towards epilepsy-associated comorbidities have yet to be determined. Thus, future studies determining the therapeutic potential of gut microbiota interventions in PWE with epilepsy-associated comorbidities may effectively improve their quality of life.
Pivotal Role of Fyn Kinase in Parkinson's Disease and Levodopa-Induced Dyskinesia: a Novel Therapeutic Target?

Angelopoulou E, Paudel YN, Julian T, Shaikh MF, Piperi C

Mol Neurobiol, 2021 Apr;58(4):1372-1391.
PMID: 33175322 DOI: 10.1007/s12035-020-02201-z

The exact etiology of Parkinson's disease (PD) remains obscure, although many cellular mechanisms including α-synuclein aggregation, oxidative damage, excessive neuroinflammation, and dopaminergic neuronal apoptosis are implicated in its pathogenesis. There is still no disease-modifying treatment for PD and the gold standard therapy, chronic use of levodopa is usually accompanied by severe side effects, mainly levodopa-induced dyskinesia (LID). Hence, the elucidation of the precise underlying molecular mechanisms is of paramount importance. Fyn is a tyrosine phospho-transferase of the Src family nonreceptor kinases that is highly implicated in immune regulation, cell proliferation and normal brain development. Accumulating preclinical evidence highlights the emerging role of Fyn in key aspects of PD and LID pathogenesis: it may regulate α-synuclein phosphorylation, oxidative stress-induced dopaminergic neuronal death, enhanced neuroinflammation and glutamate excitotoxicity by mediating key signaling pathways, such as BDNF/TrkB, PKCδ, MAPK, AMPK, NF-κB, Nrf2, and NMDAR axes. These findings suggest that therapeutic targeting of Fyn or Fyn-related pathways may represent a novel approach in PD treatment. Saracatinib, a nonselective Fyn inhibitor, has already been tested in clinical trials for Alzheimer's disease, and novel selective Fyn inhibitors are under investigation. In this comprehensive review, we discuss recent evidence on the role of Fyn in the pathogenesis of PD and LID and provide insights on additional Fyn-related molecular mechanisms to be explored in PD and LID pathology that could aid in the development of future Fyn-targeted therapeutic approaches.
Correction to: Understanding translational research in schizophrenia: A novel insight into animal models

Malik JA, Yaseen Z, Lahari T, Ahmed S, Shaikh MF, Anwar S

Mol Biol Rep, 2023 Apr 06.
PMID: 37024749 DOI: 10.1007/s11033-023-08352-1
Fulltext Understanding translational research in schizophrenia: A novel insight into animal models

Malik JA, Yaseen Z, Thotapalli L, Ahmed S, Shaikh MF, Anwar S

Mol Biol Rep, 2023 Apr;50(4):3767-3785.
PMID: 36692676 DOI: 10.1007/s11033-023-08241-7

Schizophrenia affects millions of people worldwide and is a major challenge for the scientific community. Like most psychotic diseases, it is also considered a complicated mental disorder caused by an imbalance in neurotransmitters. Due to the complexity of neuropathology, it is always a complicated disorder. The lack of proper understanding of the pathophysiology makes the disorder unmanageable in clinical settings. However, due to recent advances in animal models, we hope we can have better therapeutic approaches with more success in clinical settings. Dopamine, glutamate, GABA, and serotonin are the neurotransmitters involved in the pathophysiology of schizophrenia. Various animal models have been put forward based on these neurotransmitters, including pharmacological, neurodevelopmental, and genetic models. Polymorphism of genes such as dysbindin, DICS1, and NRG1 has also been reported in schizophrenia. Hypothesis based on dopamine, glutamate, and serotonin are considered successful models of schizophrenia on which drug therapies have been designed to date. New targets like the orexin system, muscarinic and nicotinic receptors, and cannabinoid receptors have been approached to alleviate the negative and cognitive symptoms. The non-pharmacological models like the post-weaning social isolation model (maternal deprivation), the isolation rearing model etc. have been also developed to mimic the symptoms of schizophrenia and to create and test new approaches of drug therapy which is a breakthrough at present in psychiatric disorders. Different behavioral tests have been evaluated in these specific models. This review will highlight the currently available animal models and behavioral tests in psychic disorders concerning schizophrenia.
Fulltext Immunoreactivity of Muscarinic Acetylcholine M2 and Serotonin 5-HT2B Receptors, Norepinephrine Transporter and Kir Channels in a Model of Epilepsy

Akyuz E, Doganyigit Z, Paudel YN, Koklu B, Kaymak E, Villa C, et al.

Life (Basel), 2021 Mar 26;11(4).
PMID: 33810231 DOI: 10.3390/life11040276

Epilepsy is characterized by an imbalance in neurotransmitter activity; an increased excitatory to an inhibitory activity. Acetylcholine (ACh), serotonin, and norepinephrine (NE) may modulate neural activity via several mechanisms, mainly through its receptors/transporter activity and alterations in the extracellular potassium (K+) concentration via K+ ion channels. Seizures may disrupt the regulation of inwardly rectifying K+ (Kir) channels and alter the receptor/transporter activity. However, there are limited data present on the immunoreactivity pattern of these neurotransmitter receptors/transporters and K+ channels in chronic models of epilepsy, which therefore was the aim of this study. Changes in the immunoreactivity of epileptogenesis-related neurotransmitter receptors/transporters (M2, 5-HT2B, and NE transporter) as well as Kir channels (Kir3.1 and Kir6.2) were determined in the cortex, hippocampus and medulla of adult Wistar rats by utilizing a Pentylenetetrazol (PTZ)-kindling chronic epilepsy model. Increased immunoreactivity of the NE transporter, M2, and 5-HT2B receptors was witnessed in the cortex and medulla. While the immunoreactivity of the 5-HT2B receptor was found increased in the cortex and medulla, it was decreased in the hippocampus, with no changes observed in the M2 receptor in this region. Kir3.1 and Kir6.2 staining showed increase immunoreactivity in the cerebral cortex, but channel contrasting findings in the hippocampus and medulla. Our results suggest that seizure kindling may result in significant changes in the neurotransmitter system which may contribute or propagate to future epileptogenesis, brain damage and potentially towards sudden unexpected death in epilepsy (SUDEP). Further studies on the pathogenic role of these changes in neurotransmitter receptors/transporters and K+ channel immunoreactivity may identify newer possible targets to treat seizures or prevent epilepsy-related comorbidities.
Fulltext Orthosiphon stamineus Proteins Alleviate Hydrogen Peroxide Stress in SH-SY5Y Cells

Chung YS, Ahmed PK, Othman I, Shaikh MF

Life (Basel), 2021 Jun 20;11(6).
PMID: 34202937 DOI: 10.3390/life11060585

The neuroprotective potential of Orthosiphon stamineus leaf proteins (OSLPs) has never been evaluated in SH-SY5Y cells challenged by hydrogen peroxide (H2O2). This work thus aims to elucidate OSLP neuroprotective potential in alleviating H2O2 stress. OSLPs at varying concentrations were evaluated for cytotoxicity (24 and 48 h) and neuroprotective potential in H2O2-induced SH-SY5Y cells (24 h). The protective mechanism of H2O2-induced SH-SY5Y cells was also explored via mass-spectrometry-based label-free quantitative proteomics (LFQ) and bioinformatics. OSLPs (25, 50, 125, 250, 500, and 1000 µg/mL; 24 and 48 h) were found to be safe. Pre-treatments with OSLP doses (250, 500, and 1000 µg/mL, 24 h) significantly increased the survival of SH-SY5Y cells in a concentration-dependent manner and improved cell architecture-pyramidal-shaped cells, reduced clumping and shrinkage, with apparent neurite formations. OSLP pre-treatment (1000 µg/mL, 24 h) lowered the expressions of two major heat shock proteins, HSPA8 (heat shock protein family A (Hsp70) member 8) and HSP90AA1 (heat shock protein 90), which promote cellular stress signaling under stress conditions. OSLP is, therefore, suggested to be anti-inflammatory by modulating the "signaling of interleukin-4 and interleukin-13" pathway as the predominant mechanism in addition to regulating the "attenuation phase" and "HSP90 chaperone cycle for steroid hormone receptors" pathways to counteract heat shock protein (HSP)-induced damage under stress conditions.
Cardiorespiratory findings in epilepsy: A recent review on outcomes and pathophysiology

Akyüz E, Üner AK, Köklü B, Arulsamy A, Shaikh MF

J Neurosci Res, 2021 09;99(9):2059-2073.
PMID: 34109651 DOI: 10.1002/jnr.24861

Epilepsy is a debilitating disorder of uncontrollable recurrent seizures that occurs as a result of imbalances in the brain excitatory and inhibitory neuronal signals, that could stem from a range of functional and structural neuronal impairments. Globally, nearly 70 million people are negatively impacted by epilepsy and its comorbidities. One such comorbidity is the effect epilepsy has on the autonomic nervous system (ANS), which plays a role in the control of blood circulation, respiration and gastrointestinal function. These epilepsy-induced impairments in the circulatory and respiratory systems may contribute toward sudden unexpected death in epilepsy (SUDEP). Although, various hypotheses have been proposed regarding the role of epilepsy on ANS, the linking pathological mechanism still remains unclear. Channelopathies and seizure-induced damages in ANS-control brain structures were some of the causal/pathological candidates of cardiorespiratory comorbidities in epilepsy patients, especially in those who were drug resistant. However, emerging preclinical research suggest that neurotransmitter/receptor dysfunction and synaptic changes in the ANS may also contribute to the epilepsy-related autonomic disorders. Thus, pathological mechanisms of cardiorespiratory dysfunction should be elucidated by considering the modifications in anatomy and physiology of the autonomic system caused by seizures. In this regard, we present a comprehensive review of the current literature, both clinical and preclinical animal studies, on the cardiorespiratory findings in epilepsy and elucidate the possible pathological mechanisms of these findings, in hopes to prevent SUDEP especially in patients who are drug resistant.
High mobility group box 1 (HMGB1) as a novel frontier in epileptogenesis: from pathogenesis to therapeutic approaches

Paudel YN, Semple BD, Jones NC, Othman I, Shaikh MF

J Neurochem, 2019 12;151(5):542-557.
PMID: 30644560 DOI: 10.1111/jnc.14663

Epilepsy is a serious neurological condition exhibiting complex pathology and deserving of more serious attention. More than 30% of people with epilepsy are not responsive to more than 20 anti-epileptic drugs currently available, reflecting an unmet clinical need for novel therapeutic strategies. Not much is known about the pathogenesis of epilepsy, but evidence indicates that neuroinflammation might contribute to the onset and progression of epilepsy following acquired brain insults. However, the molecular mechanisms underlying these pathophysiological processes are yet to be fully understood. The emerging research suggests that high-mobility group box protein 1 (HMGB1), a DNA-binding protein that is both actively secreted by inflammatory cells and released by necrotic cells, might contribute to the pathogenesis of epilepsy. HMGB1 as an initiator and amplifier of neuroinflammation, and its activation is implicated in the propagation of seizures in animal models. The current review will highlight the potential role of HMGB1 in the pathogenesis of epilepsy, and implications of HMGB1-targeted therapies against epilepsy. HMGB1 in this context is an emerging concept deserving further exploration. Increased understanding of HMGB1 in seizures and epilepsy will pave the way in designing novel and innovative therapeutic strategies that could modify the disease course or prevent its development.
Management of status epilepticus in Malaysia: A national survey of current practice and treatment gap

Lim KS, Khoo CS, Fong SL, Tan HJ, Fong CY, Mohamed AR, et al.

J Clin Neurosci, 2023 Aug;114:25-31.
PMID: 37279626 DOI: 10.1016/j.jocn.2023.05.006

INTRODUCTION: Early and effective treatment is fundamental in status epilepticus (SE) management. At the initiative of the Epilepsy Council of Malaysia, this study aimed to determine the treatment gap in SE across different healthcare settings in Malaysia.
METHODS: A web-based survey was sent to clinicians involved in the management of SE, across all states and at all levels of healthcare services.
RESULTS: A total of 158 responses were received from 104 health facilities, including 23 tertiary government hospitals (95.8% of all government tertiary hospitals in Malaysia), 4 (80.0%) universities, 14 (6.7%) private, 15 (11.5%) district hospitals and 21 clinics. Intravenous (IV) diazepam was available in 14 (93.3%) district and 33 (80.5%) tertiary hospitals for prehospital management. Non-IV benzodiazepine (rectal diazepam and intramuscular midazolam) was not widely available in prehospital services (75.8% and 51.5%). Intramuscular midazolam was underutilised (60.0% in district and 65.9% in tertiary hospitals). IV sodium valproate and levetiracetam were only available in 66.7% and 53.3% of the district hospitals, respectively. Electroencephalogram (EEG) services were available in only 26.7% of the district hospitals. Non-pharmacological therapies such as ketogenic diet, electroconvulsive therapy, and therapeutic hypothermia were not available in most district and tertiary hospitals for refractory and super-refractory SE.
CONCLUSIONS: We identified several gaps in the current practice of SE management, including limited availability and underutilization of non-IV midazolam in prehospital services, underutilization of non-IV midazolam and other second-line ASMs, and lack of EEG monitoring in district hospitals and limited treatment options for refractory and super-refractory SE in tertiary hospitals.

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