Herbal snuff (AK-47 and HAM) induce oxidative stress and increase acetylcholinesterase enzyme activity in rat brain

Snuff has resurfaced not only in western countries but in Africa including Nigeria. It is now almost generally acceptable, among young and old in Nigeria. This research was designed to investigate the Effect of Hajiya Aisha Manpower (HAM) and AK-47 on Antioxidant Status and Acetylcholinesterase enzyme activity (AchE) of Wister Albino Rats. Thirty (30) Wister rats (110-120 g) were arbitrarily divided into five groups. Group1 (control); received only distilled water. Groups 2 and 3 (received 6 mg and 3 mg/kg b.w.t of HAM respectively). Groups 4 and 5 (received 6 mg and 3 mg/kg b.w.t AK-47 of respectively). After two months of treatments, the rats were anesthetized, blood samples were taken through heart puncture and brains of all rats were isolated and homogenized. The Result revealed Non-significant decrease in Superoxide dismutase (SOD), glutathione peroxidase (GPx) activities and concomitant increase in GSH levels in treatment groups were observed in relation to the control. While a substantial increase (p˂ 0.5) in MDA was detected in treatment groups. Brain AchE activity increased significantly in all treatment groups in relation to the control. We conclude that Both AK-47 and HAM at high concentration induce oxidative stress, decreased antioxidant enzyme activities and promote degradation of acetylcholine in rat brain homogenate.

Synthesis, Pharmacological Evaluation, and Computational Studies of Cyclic Opioid Peptidomimetics Containing β3-Lysine

Our formerly described pentapeptide opioid analog Tyr-c[D-Lys-Phe-Phe-Asp]NH2 (designated RP-170), showing high affinity for the mu (MOR) and kappa (KOR) opioid receptors, was much more stable than endomorphine-2 (EM-2) in the rat brain homogenate and displayed remarkable antinociceptive activity after central (intracerebroventricular) and peripheral (intravenous) administration. In this report, we describe the further modification of this analog, which includes the incorporation of a β3-amino acid, (R)- and (S)-β3-Lys, instead of D-Lys in position 2. The influence of such replacement on the biological properties of the obtained analogs, Tyr-c[(R)-β3-Lys-Phe-Phe-Asp]NH2 (RP-171) and Tyr-c[(S)-β3-Lys-Phe-Phe-Asp]NH2, (RP-172), was investigated in vitro. Receptor radiolabeled displacement and functional calcium mobilization assays were performed to measure binding affinity and receptor activation of the new analogs. The obtained data revealed that only one of the diastereoisomeric peptides, RP-171, was able to selectively bind and activate MOR. Molecular modeling (docking and molecular dynamics (MD) simulations) suggests that both compounds should be accommodated in the MOR binding site. However, in the case of the inactive isomer RP-172, fewer hydrogen bonds, as well as instability of the canonical ionic interaction to Asp147, could explain its very low MOR affinity.

New In Vitro Methodology for Kinetics Distribution Prediction in the Brain. An Additional Step towards an Animal-Free Approach

The development of new drugs or formulations for central nervous system (CNS) diseases is a complex pharmacologic and pharmacokinetic process; it is important to evaluate their access to the CNS through the blood−brain barrier (BBB) and their distribution once they have acceded to the brain. The gold standard tool for obtaining this information is the animal microdialysis technique; however, according to 3Rs principles, it would be better to have an “animal-free” alternative technique. Because of that, the purpose of this work was to develop a new formulation to substitute the brain homogenate in the in vitro tests used for the prediction of a drug’s distribution in the brain. Fresh eggs have been used to prepare an emulsion with the same proportion in proteins and lipids as a human brain; this emulsion has proved to be able to predict both the unbound fraction of drug in the brain (fu,brain) and the apparent volume of distribution in the brain (Vu,brain) when tested in in vitro permeability tests. The new formulation could be used as a screening tool; only the drugs with a proper in vitro distribution would pass to microdialysis studies, contributing to the refinement, reduction and replacement of animals in research.

PI3K/AKT/mTOR Signalling Inhibitor Chrysophanol Ameliorates Neurobehavioural and Neurochemical Defects in Propionic Acid-induced Experimental Model of Autism in Adult Rats

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder marked by social and communication deficits as well as repetitive behaviour. Several studies have found that overactivation of the PI3K/AKT/mTOR signalling pathways during brain development plays a significant role in autism pathogenesis. Overexpression of the PI3K/AKT/mTOR signalling pathway causes neurological disorders by increasing cell death, neuroinflammation, and oxidative stress. Chrysophanol, also known as chrysophanic acid, is a naturally occurring chemical obtained from the plant Rheum palmatum. This study aimed to examine the neuroprotective effect of CPH on neurobehavioral, molecular, neurochemical, and gross pathological alterations in ICV-PPA induced experimental model of autism in adult rats. The effects of ICV-PPA on PI3K/AKT/mTOR downregulation in the brain were studied in autism-like rats. Furthermore, we investigated how CPH affected myelin basic protein (MBP) levels in rat brain homogenate and apoptotic biomarkers such as caspase-3, Bax, and Bcl-2 levels in rat brain homogenate and blood plasma samples. Rats were tested for behavioural abnormalities such as neuromuscular dysfunction using an actophotometer, motor coordination using a beam crossing task (BCT), depressive behaviour using a forced swim test (FST), cognitive deficiency, and memory consolidation using a Morris water maze (MWM) task. In PPA-treated rats, prolonged oral CPH administration from day 12 to day 44 of the experimental schedule reduces autistic-like symptoms. Furthermore, in rat brain homogenates, blood plasma, and CSF samples, cellular, molecular, and cell death markers, neuroinflammatory cytokines, neurotransmitter levels, and oxidative stress indicators were investigated. The recent findings imply that CPH also restores abnormal neurochemical levels and may prevent autism-like gross pathological alterations, such as demyelination volume, in the rat brain.

Solanesol Mediated SIRT-1 Activation Prevents Neurobehavioral and Neurochemical Defects in Ouabain-Induced Experimental Model of Bipolar Disorder in Rats

Background Bipolar disorder (BD) is a chronic mental illness characterized by mood fluctuations that range from depressive lows to manic highs. Several studies have linked the downregulation of SIRT-1 (silent mating type information regulation-2 homologs) signaling to the onset of BD and other neurological dysfunctions. The purpose of this research was to look into the neuroprotective potential of Solanesol (SNL) in rats given ICV-Ouabain injections, with a focus on its effect on SIRT-1 signaling activation in the brain. Ouabain, which is found in hypothalamic and medullary neurons, is an endogenous inhibitor of brain Na+/K+ ATPase. The inhibition of brain Na+/K+ ATPase by Ouabain may also result in changes in neurotransmission within the central nervous system. SNL is a Solanaceae family active phytoconstituent produced from the plant Nicotiana tabacum. SNL is used as a precursor for the production of CoQ10 (Coenzyme Q10), a powerful antioxidant and neuroprotective compound. In the current study, lithium (Li), an important mood stabilizer drug, was used as a control. Methods This study looked at the neuroprotective potential of SNL at dosages of 40 and 80 mg/kg in ICV-OUA injections that caused BD-like neurobehavioral and neurochemical defects in Wistar rats. Wistar rats were placed into eight groups (n=6) and administered 1 mM/0.5µl ICV-OUA injections for three days. Neurochemical assessments were done in rat brain homogenates, CSF, and blood plasma samples at the end of the experiment protocol schedule. Results Long-term SNL and lithium administration have been shown to decrease the number of rearing and crossings, as well as reduce time spent in the center, locomotor activities, and immobility time. Solansesol treatment gradually raises the amount of Na+/K+ ATPase, limiting the severity of behavioural symptoms. These findings also revealed that SNL increases the levels of SIRT-1 in CSF, blood plasma, and brain homogenate samples. Furthermore, in rat brain homogenates and blood plasma samples, SNL modulates apoptotic markers such as Caspase-3, Bax (pro-apoptotic), and Bcl-2 (anti-apoptotic). Mitochondrial-ETC complex enzymes, including complex-I, II, IV, V, and CoQ10, were also restored following long-term SNL treatment. Furthermore, SNL lowered inflammatory cytokines (TNF-α, IL-1β) levels while restoring neurotransmitter levels (serotonin, dopamine, glutamate, and acetylcholine) and decreasing oxidative stress markers. Conclusion As a result, our findings suggest that SNL, as a SIRT-1 signalling activator, may be a promising therapeutic approach for BD-like neurological dysfunctions.

Reducing voltage-dependent potassium channel Kv3.4 levels ameliorates synapse loss in a mouse model of Alzheimers disease

Synapse loss is associated with cognitive decline in Alzheimers disease (AD) and owing to their plastic nature, synapses are an ideal target for therapeutic intervention. Oligomeric amyloid beta (Ab) around amyloid plaques is known to contribute to synapse loss in mouse models and is associated with synapse loss in human AD brain tissue, but the mechanisms leading from Ab; to synapse loss remain unclear. Recent data suggest that the fast-activating and -inactivating voltage-gated potassium channel subtype 3.4 (Kv3.4) may play a role in Ab-mediated neurotoxicity. Here, we tested whether this channel could also be involved in Ab synaptotoxicity. Using adeno-associated virus and CRISPR (clustered regularly interspaced short palindromic repeats) technology, we reduced Kv3.4 expression in neurons of the somatosensory cortex of APP/PS1 mice. These mice express human familial AD associated mutations in amyloid precursor protein and presenilin 1 and develop amyloid plaques and plaque-associated synapse loss similar to that observed in AD brain. We observe that reducing Kv3.4 levels ameliorates dendritic spine loss and changes spine morphology compared to control virus. In support of translational relevance, Kv3.4 protein was observed in human AD and control brain and is associated with synapses in human iPSC-derived cortical neurons. Interestingly, we observe a decrease in Kv3.4 expression in iPSC derived cortical neurons when they are challenged with human Alzheimers disease derived brain homogenate. These results suggest that approaches to reduce Kv3.4 expression and/or function could be protective against Ab-induced synaptic alterations.

DDRE-08. A BIOANALYTICAL LC-MS/MS ASSAY TO QUANTIFY TOTAL AND UNBOUND LY3214996, ABEMACICLIB AND ITS ACTIVE METABOLITES IN HUMAN PLASMA, CEREBROSPINAL FLUID AND HUMAN GLIOBLASTOMA

BACKGROUND Here, we report on our development and validation of a sensitive and rapid LC-MS/MS method for the determination of total and unbound concentrations of ERK inhibitor LY3214996, CDK4/6 inhibitor abemaciclib and its M2 and M20 active metabolites in human plasma, cerebrospinal fluid and human glioblastoma tissue. METHODS Analytes were extracted from patient plasma, CSF and glioblastoma homogenate samples by protein precipitation with methanol. Four levels of quality controls were used during validation. The method was validated according to FDA guidelines and CAP/CLIA regulations. Equilibrium dialysis was performed to determine unbound fraction of four analytes in plasma and brain tissue. The detection was performed on Sciex QTRAP 6500+ mass spectrometer in positive electrospray ionization mode. RESULTS The method was validated over a concentration range from 0.2-500 nmol/L for all four analytes. The analytical separation was optimized on Phenomenex Kinetex™ F5 column with total run time of 3.8 min using gradient elution. For all the analytes the maximum coefficient of variation for intra- and inter-day precision was 12.0% and the accuracy was within 90.2-119.7% in all matrixes. The analytes are stable in plasma and brain homogenate for at least 19 hours and 6 hours at room temperature (RT), respectively. Stability of stock and working solutions was demonstrated for at least 15 hours (RT) and 28 days (2-8°C). The unbound fraction of the analytes in pooled human plasma and brain were determined to be 0.371 and 0.065 for LY3214996, 0.026 and 0.013 for abemaciclib, 0.052 and 0.008 for M2, 0.024 and 0.021 for M20, respectively. CONCLUSIONS A bioanalytical method to quantify LY3214996, abemaciclib and its M2 and M20 metabolites is successfully developed and validated. The method is currently applied to evaluate plasma pharmacokinetics and CNS penetration of LY3214996 and abemaciclib in recurrent glioblastoma patients in an ongoing Phase 0 clinical trial (NCT04391595).

BIOM-13. DEVELOPMENT AND VALIDATION OF AN LC-MS/MS ASSAY TO MEASURE GLUTATHIONE, GLUTATHIONE DISULFIDE, CYSTEINE, AND CYSTINE IN HUMAN BRAIN AND HUMAN GLIOBLASTOMA

BACKGROUND Oxidative stress is implicated in many pathological conditions. Herein, we report on our development and validation of a sensitive and rapid LC-MS/MS method for the determination of oxidative stress biomarkers glutathione (GSH), glutathione disulfide (GSSG), cysteine (Cys) and cystine (CySS) in human brain and glioblastoma tissue. METHODS Freshly-acquired human glioblastoma tissue was homogenized with N-ethylmaleimide solution to prevent thiol oxidation. Analytes were then extracted from homogenate samples by protein precipitation with 2% sulfosalicylic acid (SSA). Stable isotope-labeled analytes were used as internal standards. Independent calibration curves for thiols and disulfides were prepared in analytical solutions. Three levels of quality controls were prepared in human brain homogenate. The detection was performed on Sciex QTRAP 6500+ mass spectrometer in positive electrospray ionization mode. RESULTS Linear regression model was used to cover a concentration ranging 0.4-100 µmol/L for GSSG/CySS and 1-400 µmol/L for GSH/Cys. Chromatographic separation was optimized on Intrada Amino Acid column with total run time of 5 min using gradient elution. For all analytes the maximum coefficient of variation for intra- and inter-day precision was 11.4% and the accuracy was within 80.9-113.7% in analytical solution and matrix. The analytes were stable in brain homogenate for 1 hour and 3 hours at room temperature (RT) and 4 °C, respectively. Stability at -80°C was demonstrated for at least 35 days in human brain homogenate. Stability of stock and working solutions was demonstrated for at least 4 hours (RT) and 25 days (-20°C). CONCLUSIONS A bioanalytical method to quantify GSH, GSSG, Cys, and CySS is successfully developed and validated. The method is currently applied to measure thiols and related disulfides in human glioblastoma tissue undergoing 5-aminolevulinic acid sonodynamic therapy (NCT04559685).

Reductions in Hydrogen Sulfide Precede Onset of Mitochondrial Quality Control in the Corneal Kindled Mouse Model of Epilepsy

Epilepsy is a heterogenous neurological disorder characterized by recurrent unprovoked seizures, mitochondrial stress, and neurodegeneration. Hydrogen sulfide (H2S), a gasotransmitter, promotes mitochondrial function and biogenesis, elicits neuromodulation and neuroprotection, and may acutely suppress seizures. A major gap in knowledge remains in understanding the role of mitochondrial dysfunction and progressive changes in H2S levels following acute seizures and during epileptogenesis. We thus sought to quantify changes in H2S and its methylated metabolite (MeSH) via LC-MS/MS subsequent to acute maximal electroshock and 6 Hz 44 mA seizures in mice, as well as in the corneal kindled mouse model of chronic seizures. Plasma H2S was acutely reduced after a maximal electroshock seizure. H2S or MeSH levels in whole brain homogenate and expression of related genes in corneal kindled mice were not altered. However, plasma H2S and MeSH levels were significantly lower during kindling, but not after established kindling. Morever, we demonstrated a time-dependent increase in expression of mitochondrial membrane integrity-related proteins, Opa1, Mfn2, Drp1, and Mff during kindling, which did not correlate with gene expression. Taken together, short-term reductions in plasma H2S could be a novel biomarker for seizures. Future studies should further define the role of H2S and mitochondrial stress in epilepsy.

Neuroprotective Potentials of Cocculus hirsutus Leaf Extract Against 6,7-Epoxytropine Tropate-Induced Memory Impairment in Rats

Cocculus hirsutus, a tropical South Asian creeper,traditionally used as a diuretic, laxative, cardiotonic, anti-microbial, antidiabetic, anti-inflammatory and spermatogenic. However, the neuroprotective role was less explored; therefore, this researchwas conducted to investigate neuroprotective potentials of Cocculus hirsutus leaf hydroalcoholic extract in 6,7-Epoxytropine tropate (Scopolamine) induced cognitive impairment and oxidative lipid peroxidation in the brain of wistar albino rat. Scopolamine (1 mg/kg body weight, i.p.) was given in rats for 14 days to induce transient cognitive impairment. Donepezil (2 mg/kg body weight, orally) has been used for this research as a positive control. Behavioral studies were done using Morris water maze and elevated plus maze and neurobiochemical parameters such as acetylcholinesterase activity, reduced glutathione levels and activity of catalase were assessed in rats brain homogenate. Cocculus hirsutus leaf hydroalcoholic extract(200 mg/kg and 400 mg/kg) exhibited an improvement in spatial, exteroceptive learning and memory. The extract showed significant decline in the activity of acetylcholinesterase, enhancement of reduced glutathione levels and catalase activity (p<0.001). All the outcomes were assessed by Bonferroni post hoc tests with ANOVA for multiple comparison studies. This study reveals that hydroalcoholic extract of Cocculus hirsutusleaf acts as neuroprotective against scopolamine induced behavioral and neurobiochemical changes.