Effects of Aluminum Oxide Nanoparticles in the Spinal Cord of Male Wistar Rats and the Potential Ameliorative Role of Melatonin

Aluminum oxide nanoparticles (Al2O3 NPs) are widely utilized in vaccine manufacturing and other medical preparations. Melatonin has numerous effects as an antioxidant and anti-apoptotic. The purpose of this study was to examine the beneficial impact of melatonin on Al2O3 NPs toxicity in the spinal cord. Forty male rats were divided into four groups: Group I, the negative controls (received standard diet and distilled water); Group II, Al2O3 NPs (received 30 mg/kg bw Al2O3 NPs); Group III, melatonin and Al2O3 NPs (received 30 mg/kg bw Al2O3 NPs + 10 mg/kg bw melatonin); Group IV, melatonin (received 10 mg/kg bw melatonin). All treatments were administered daily for 28 days by gastric gavage. After that, all rats were sacrificed, then, the samples from different spinal cords were subjected to histopathological, biochemical, and immunohistochemical analyses. Al2O3 NPs markedly elevated malondialdehyde and 8-hydroxydeoxyguanosine while inhibiting superoxide dismutase and catalase. Al2O3 NPs also induced histological alterations in both gray and white matter manifested by neuronal degeneration, vacuolation, axonal degeneration, ballooning, and fusion of myelin sheaths. Furthermore, immunohistochemical results displayed a strong positive expression of caspase-3. Conversely, melatonin significantly mitigated the effects of Al2O3 NPs by increasing the activities of antioxidant enzymes and inhibiting malondialdehyde and 8-hydroxydeoxyguanosine. Moreover, melatonin alleviated most histological alterations induced by Al2O3 NPs and reduced caspase-3 immunoreactivity. Collectively, melatonin could protect the spinal cord and mitigate Al2O3 NPs-induced neurotoxicity.

Nano-Mediated Molecular Targeting in Diagnosis and Mitigation of Wilson Disease

Wilson disease, a rare genetic disorder resulting from mutations in the ATP7B gene disrupts copper metabolism, leading to its harmful accumulation in hepatocytes, the brain, and other organs. It affects roughly 1 in 30,000 individuals, with 1 in 90 being gene carriers. Beyond gene mutations, the disease involves complex factors contributing to copper imbalance. Ongoing research seeks to unravel intricate molecular pathways, offering fresh insights into the disease's mechanisms. Simultaneously, there is a dedicated effort to develop effective therapeutic strategies. Nanotechnology-driven formulations are showing promise for both treatment and early diagnosis of Wilson disease. This comprehensive review covers the entire spectrum of the condition, encompassing pathophysiology, potential biomarkers, established and emerging therapies, ongoing clinical trials, and innovative nanotechnology applications. This multifaceted approach holds the potential to improve our understanding, diagnosis, and management of Wilson's disease, which remains a challenging and potentially life-threatening disorder.

Copper: From enigma to therapeutic target for neurological disorder

Neurological disorders (NDs) have a negative impact on the lives of individuals. There could be two explanations for this: unclear aetiology and lack of effective therapy. However, research in the past few years has revealed the role of bio-metals dyshomeostasis in NDs. The imbalance in copper (Cu) concentration may be one of the main causative factors in NDs. In this review, we have discussed the role of Cu in NDs, especially Alzheimer's disease (AD), including the molecular mechanisms involved in Cu-associated NDs like oxidative stress, neuroinflammation, and protein misfolding. We have also summarized the recent Cu-targeting approaches and highlighted the in vitro and in vivo studies recently being reported on the subject. Based on the earlier published reports, it could be speculated that the Cu targeting strategy might be an interesting and potential therapeutic approach for NDs. Various difficulties must be overcome to develop safe and efficient Cu-targeting medications for NDs.

Unleashing new MTDL AChE and BuChE inhibitors as potential anti-AD therapeutic agents: In vitro, in vivo and in silico studies

Alzheimer's disease (AD) is challenging due to its irreversible declining cognitive symptoms and multifactorial nature. This work tackles targeting both acetylcholinesterase (AChE) and BuChE with a multitarget-directed ligand (MTDL) through design, synthesis, and biological and in silico evaluation of a series of twenty eight new 5-substituted-2-anilino-1,3,4-oxadiazole derivatives 4a-g, 5a-g, 9a-g and 13a-g dual inhibitors of the target biomolecules. In vitro cholinesterases inhibition and selectivity assay of the synthesized derivatives showed excellent nanomolar level inhibitory activities. Compound 5a, the most potent inhibitor, elicited IC50s of 46.9 and 3.5 nM against AChE and BuChE, respectively (SI = 0.07), 5 folds better than the known dual inhibitor Rivastagmine. In vivo and ex vivo investigation showed that 5a significantly inhibited MDA levels and increased GSH contents, thus, attenuating the brain tissue oxidative stress. Additionally, 5a significantly decreased AChE and BuChE levels and inhibited self-mediated β-amyloid aggregation in brains of treated rats. Histopathological and immunohistochemical evaluation demonstrated lessened damage and decreased caspase-3 and VEGF expression levels. In silico prediction of 5a's pharmacokinetics and toxicity profiles reflected promising results. Finally, 5a demonstrated tight binding interactions with the two target biomolecules upon docking along with stable complex formation with its bio-targets throughout the 100 ns MD trajectories.

Synthesis and evaluation of small organic molecule as reactivator of organophosphorus inhibited acetylcholinesterase

A series of uncharged salicylaldehyde oximes were synthesized and evaluated for the reactivation of organophosphorus (OP) nerve agents simulants Diethylchlorophosphonate (DCP) & Diethylcyanophosphonate (DCNP) and pesticides (paraoxon & malaoxon) inhibited electric eel Acetylcholinesterase (AChE). The computational software Swiss ADME and molinspiration were used to unfold the probability of drug-likeness properties of the oximes derivatives. Substituted aromatic oximes with diethylamino or bromo group with free hydroxyl group ortho to oxime moiety were found efficient to regenerate the enzymatic activity in in-vitro AChE assay. The alkylation of the ortho hydroxyl group of derivatives led to the loss of reactivation potential. The derivatives with a hydroxyl group and without oxime group and vice versa did not show significant reactivation potency against tested OP toxicants. Further, we also evaluated the reactivation potential of these selected molecules on the rat brain homogenate against different OPs inhibited ChE and found maximum reactivation potency of oxime 2e. The in-vitro results were further validated by molecular docking and dynamic studies which showed that the hydroxyl group interacted with serine amino acids in the catalytic anionic site of AChE enzyme and was stable up to 200 ns consequently providing proper orientation to oxime moiety for reactivating the OP inhibited enzyme. It has thus been proved by the structure-activity relationship of oximes derivatives that hydroxyl group ortho to oxime is essential for reactivating OP inhibited electric eel AChE. Amongst the twenty-one oximes derivatives, 2e was found to be most active in regenerating the paraoxon, malaoxon, DCP and DCNP inhibited AChE enzyme.

Induction of mitophagy via ROS-dependent pathway protects copper-induced hypothalamic nerve cell injury

Copper (Cu) is one of the essential trace elements in the body, but excessive amounts of Cu harm multiple organs and tissues such as liver, kidneys, testis, ovaries, and brain. However, the mechanism of hypothalamic neurotoxicity induced by Cu is still unknown. This study examined the relationship between reactive oxygen species (ROS) and mitophagy in mouse hypothalamus treated with high Cu. The results demonstrated that high levels of copper sulfate (CuSO4) could cause histopathological and neuronal changes in the mouse hypothalamus, produce a large amount of ROS, induce mitophagy, and lead to an imbalance of mitochondrial fusion/fission. The main manifestations are an increase in the expression levels of LC3-II/LC3-I, p62, DRP1, and FIS1, and a decrease in the expression levels of MFN1 and MFN2. Cu can induce mitophagy also was confirmed by LC3 co-localization with TOMM20 (mitochondrial marker). Next, the effect of oxidative stress on CuSO4-induced mitophagy was demonstrated. The results showed that ROS inhibitor N-acetylcysteine (NAC) diminished CuSO4-induced mitophagy and reversed the disturbance of mitochondrial dynamics. Additionally, a study was carried out to evaluate the role of mitophagy in CuSO4-induced hypothalamic injury. The inhibition of mitophagy using mitophagy inhibitor (Mdivi-1) decreased cell viability and promoted CuSO4-inhibited mitochondrial fusion. The aforementioned results suggested that CuSO4 induced mitophagy via oxidative stress in N38 cells and mouse hypothalamus, and that the activation of mitophagy might generate protective mechanisms by alleviating Cu-induced mitochondrial dynamics disorder. This study provided a novel approach and theoretical basis for studying and preventing Cu neurotoxicity.

Alpha Lipoic Acid and Monoisoamyl-DMSA Combined Treatment Ameliorates Copper-Induced Neurobehavioral Deficits, Oxidative Stress, and Inflammation

Copper (Cu), being an essential trace metal, plays several roles in biological processes, though exposure to Cu can be potentially toxic to the brain and a few other soft organs. In the present study, we investigated the effects of the combined administration of monoisoamyl 2, 3-dimercaptosuccinic acid (MiADMSA), which is a new chelator, and alpha lipoic acid (ALA) and an antioxidant that is made naturally in the body and is also found in foods, against Cu-induced oxidative stress in rats. Rats were exposed to 20 mg/kg copper sulfate for 16 weeks once a day via the oral route. After 16 weeks of exposure, animals were divided into different sub-groups. Group I was divided into three subgroups: Group IA, control; Group IB, MiADMSA (75 mg/kg, oral); Group IC, ALA (75 mg/kg, oral), while Group II was divided into four subgroups: Group IIA, Cu pre-exposed; Group IIB, Cu+ MiADMSA; Group IIC, Cu+ ALA; Group IID, Cu+ ALA+ MiADMSA. Exposure to Cu led to significant neurobehavioral abnormalities; treatment with MiADMSA, and in particular MiADMSA + ALA, significantly ameliorated the neurobehavioral parameters and restored the memory deficits in rats. Oxidative stress variables (ROS, nitrite, TBARS, SOD, catalase) and inflammatory markers (TNF-α, and IL-1β), which were altered on Cu exposed rats, also responded favorably to ALA+ MiADMSA combined treatment. Thus, combined administration of MiADMSA and ALA might be a better treatment strategy than monotherapy with MiADMSA or ALA against Cu-induced neurotoxicity, particularly in reducing oxidative stress, neurobehavioral abnormalities, and inflammatory markers.

Chemistry, Pharmacology, and Toxicology of Monoisoamyl Dimercaptosuccinic Acid: A Chelating Agent for Chronic Metal Poisoning

Arsenic, a metalloid, is known to cause deleterious effects in various body organs, particularly the liver, urinary bladder, and brain, and these effects are primarily mediated through oxidative stress. Chelation therapy has been considered one of the promising medical treatments for arsenic poisoning. Meso 2,3- dimercaptosuccinic acid (DMSA) has been recognized as one of the most effective chelating drugs to treat arsenic poisoning. However, the drug is compromised with a number of shortcomings, including the inability to treat chronic arsenic poisoning due to its extracellular distribution. Monoisoamyl 2,3-dimercaptosuccinic acid, one of the analogues of meso 2,3-dimeraptosuccinic acid (DMSA), is a lipophilic chelator and has shown promise to be considered as a potential future chelating agent/antidote not only for arsenic but also for a few other heavy metals like lead, mercury, cadmium, and gallium arsenide. The results from numerous studies carried out in the recent past, mainly from our group, strongly support the clinical application of MiADMSA. This review paper summarizes most of the scientific details including the chemistry, pharmacology, and safety profile of MiADMSA. The efficacy of MiADMSA mainly against arsenic toxicity but also a few other heavy metals was also discussed. We also reviewed a few other strategies in order to achieve the optimum effects of MiADMSA, like combination therapy using two chelating agents or coadministration of a natural and synthetic antioxidant (including phytomedicine) along with MiADMSA for treatment of metal/metalloid poisoning. We also briefly discussed the use of nanotechnology (nano form of MiADMSA i.e. nano-MiADMSA) and compared it with bulk MiADMSA. All these strategies have been shown to be beneficial in getting more pronounced therapeutic efficacy of MiADMSA, as an adjuvant or as a complementary agent, by significantly increasing the chelating efficacy of MiADMSA.

Discovery of New 1,3,4-Oxadiazoles with Dual Activity Targeting the Cholinergic Pathway as Effective Anti-Alzheimer Agents

Finding an effective anti-Alzheimer agent is quite challenging due to its multifactorial nature. As such, multitarget directed ligands (MTDLs) could be a promising paradigm for finding potential therapeutically effective new small-molecule bioactive agents against Alzheimer's disease (AD). We herein present the design, synthesis, and biological evaluation of a new series of compounds based on a 5-pyrid-3-yl-1,3,4-oxadiazole scaffold. Our synthesized compounds displayed excellent in vitro enzyme inhibitory activity at nanomolar (nM) concentrations against two major AD disease-modifying targets, i.e., acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Among our compounds, 5e was considered the best dual inhibitor of both AChE (IC₅₀ = 50.87 nM) and BuChE (IC₅₀ = 4.77 nM), where these values surpassed those of rivastagmine (the only FDA-approved dual AChE and BuChE inhibitor) in our study. Furthermore, in vivo and ex vivo testing of the hit compound 5e highlighted its significant AD-biotargeting effects including reducing the elevated levels of lipid peroxidation and glutathione (GSH), normalizing levels of 8-OHdG, and, most importantly, decreasing the levels of the well-known AD hallmark β-amyloid protein. Finally, the binding ability of 5e to each of our targets, AChE and BuChE, was confirmed through additional molecular docking and molecular dynamics (MD) simulations that reflected good interactions of 5e to the active site of both targets. Hence, we herein present a series of new 1,3,4-oxadiazoles that are promising leads for the development of dual-acting AChE and BuChE inhibitors for the management of AD.

Dose-dependent hepatic toxicity and oxidative stress on exposure to nano and bulk selenium in mice

Selenium is an essential mineral naturally found in soil, water, and some of the food and is required as essential elements in human and animal body. Se supplementation is required especially for those having Se deficiency. Food supplement of selenium has several forms such as selenocysteine, selenite, selenomethionine, and selenate. Recently, Se supplement as selenium nanoparticles (SeNPs) has gained worldwide attention due to its bioactivities and properties. In the present study, we determined the potential hepatotoxicity of nano and bulk selenium using low and high doses in mice. Twenty-five Swiss albino mice (n=5) were randomly divided into 5 groups and treated orally for 28 days: Group 1: sterile saline (0.9%) as a control; Group 2: sodium selenite (1mg/kg); Group 3: sodium selenite (4mg/kg); Group 4: selenium nanoparticles (1mg/kg); and Group 5: selenium nanoparticles (4mg/kg). Administration of nano-selenium (70-90 nm) led to an increase in the activities of serum transaminases (ALT and AST), while no significant effects were noted on biochemical variables indicative of changes in heme synthesis pathway and oxidative stress like blood δ-aminolevulinic acid dehydratase (δ-ALAD), hepatic reactive oxygen species (ROS), catalase activity, superoxide dismutase (SOD), malondialdehyde assay (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG), glutathione peroxidase (GPx) compared to controls, and a high dose of sodium selenite. Our results suggest that nano-selenium at low dose (1mg/kg) exhibited antioxidant effects in the liver compared to the high dose (4mg/kg) of SeNPs and sodium selenite (1 and 4 mg/kg). The data from the present study might be useful for pharmacologists and toxicologists in providing future directions while designing selenium-based therapeutic strategies.

MiADMSA abrogates sodium tungstate-induced oxidative stress in rats

Tungsten (W) and its compounds have emerged as a relatively new area of environmental health concern in the last decade. Tungsten is environmentally benign due to its increasing use in armour-piercing munitions and as a replacement for lead in other ammunition. It has also been identified in various hazardous waste sites and therefore been proposed for inclusion in the Environmental Protection Agency National Priorities List. The major objective of this study was to evaluate the therapeutic efficacy of orally administered monoisoamyl 2, 3-dimercaptosuccinic acid (MiADMSA) against tungstate induced oxidative injury in blood, liver and kidneys of male Wistar rats. MiADMSA, a thiol chelator has gained wide recognition recently as a future chelating drug of choice specifically for arsenic and was chosen for this study as tungstate ions too have an affinity toward the -SH group thus, being less bioavailable in the body. We determined the effects of MiADMSA (50 mg/kg, p.o.) against sodium tungstate (500 ppm in drinking water, daily for 28 days) induced biochemical changes indicative of oxidative stress in blood, and other soft tissues of of male Wistar rats. Tungsten exposure led to an increased levels of Reactive Oxygen Species (ROS) in liver, kidney, spleen and blood accompanied also by an increase in TBARS levels. The GSH: GSSG ratio also showed a decrease on sodium tungstate intoxication. Treatment with MiADMSA restored most of the sodium tungstate-induced alterations in the biomarkers suggestive of oxidative stress. These preliminary results led us to conclude that sub-acute exposure to tungstate-induced oxidative stress could be effectively reduced by the administration of MiADMSA and thus might be a promising antidote for studying in detail its efficacy in reducing body tungstate burden and its excretion post tungstate exposure.

Alpha-Lipoic Acid Protects Co-Exposure to Lead and Zinc Oxide Nanoparticles Induced Neuro, Immuno and Male Reproductive Toxicity in Rats

We evaluated the neuro-, immuno-, and male reproductive toxicity of zinc oxide nanoparticles (ZnO NPs) alone and in combination with lead acetate. We also studied the therapeutic role of α-lipoic acid postexposure. Lead (10 mg/kg, body weight), ZnO NPs (100 mg/kg, bwt) alone, and their combination were administered orally in Wistar rats for 28 days, followed by the administration of α-lipoic acid (15 mg/kg, bwt) for the next 15 days. Our results demonstrated protective effects of α-lipoic acid on lead and ZnO NP-induced biochemical alterations in neurological, immunological, and male reproductive organs in rats. The altered levels of blood δ-aminolevulinic acid dehydratase (ALAD), immunoglobulins (IgA, IgG, IgM, and IgE), interleukins (IL-1β, IL-4, and IL-6), caspase-3, and tumor necrosis factor (TNF-α) were attenuated by lipoic acid treatment. Lead and ZnO NP-induced oxidative stress was decreased by lipoic acid treatment, while a moderate recovery in the normal histoarchitecture of the brain section (cortex and hippocampus) and testes further confirmed the neuro- and male reproductive toxicity of lead and ZnO NPs. We also observed a significant decrease in the blood metal content in the animals treated with lipoic acid compared to the lead-administered group, indicating the moderate chelating property of lipoic acid. It may thus be concluded that lipoic acid might be a promising protective agent against lead and ZnO NP-induced alterations in the neurological, immunological, and reproductive parameters.

Interaction study of monoisoamyl dimercaptosuccinic acid with bovine serum albumin using biophysical and molecular docking approaches

Monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA), a lipophilic chelator has been evaluated for its potential use as an antidote in arsenic poisoning. The pharmacokinetics and pharmacodynamics properties of a drug could be understood via study its mechanism of interaction with bovine serum albumin protein (BSA). Therefore, the interaction between MiADMSA with BSA was investigated using various spectroscopic techniques and computational methods. Linear quenching of BSA intrinsic fluorescence intensity with the increasing concentration of MiADMSA was observed in the fluorescence study. Furthermore, synchronous results revealed that MiADMSA slightly changed the conformation of BSA. The binding constant value of the BSA-MiADMSA complex was found 1.60 × 104 M-1 at 298 K. The value of thermodynamic parameters ΔG, ΔH, and ΔS described that the process is spontaneous, endothermic, and hydrophobic forces are involved in the interaction of MiADMSA with BSA. Competitive site marker experiments showed that MiADMSA binds to site-II of BSA. Conformational changes of BSA with the interaction of MiADMSA were apparent by CD, UV-Visible, FT-IR, and 3D fluorescence spectroscopy. To strengthen the experimental findings we have also performed a theoretical study on the BSA-MiADMSA complex. Two sites were identified with docking score of - 6.642 kcal/mol at site IIa and - 3.80 kcal/mol for site IIb via molecular docking study. Molecular dynamics simulation study inferred the stability of the BSA-MiADMSA complex which was analyzed in a long simulation run. The experimental and computational studies have shown the effective binding of MiADMSA with BSA which is essential for the transportation and elimination of a drug from the body.

Synthesis, Molecular Docking, BSA, and in-vitro reactivation study of imidazopyridine oxime against paraoxon inhibited acetylcholinesterase

AIM

To synthesize and evaluate the fused heterocyclic imidazopyridine oxime as a reactivator against paraoxon inhibited acetylcholinesterase.

BACKGROUND

Organophosphorus compounds (OPs) include parathion, malathion, chlorpyrifos, monocrotophos, and diazinon which are commonly used in agriculture for enhancing agricultural productivity via killing crop-damaging pests. However, people may get exposed to OPs pesticides unintentionally/intentionally via ingestion, inhalation or dermal. The current treatment regimen includes reactivator such as mono or bis-pyridinium oximes along with anticholinergic and an anticonvulsant drugs are recommended for the treatment of OP poisoning. Unfortunately, the drawback of the existing reactivator is that owing to the permanent charge present on the pyridinium makes them inefficient to cross the blood-brain barrier (BBB) and reactivate OP-inhibited central nervous system (CNS) acetylcholinesterase. Therefore, there is a need of reactivator that could cross the BBB and reactivate the OP inhibited acetylcholinesterase.

OBJECTIVE

The objectives of the study were synthesis, molecular docking, BSA binding and in-vitro estimation of oximes of various substituted imidazo [1,2-a]pyridine against paraoxon inhibited acetylcholinesterase.

METHOD

The reactivators were synthesized in three steps and characterized using various spectroscopic techniques. Molecular docking study was performed on 2WHP and 3ZLV PDB using Autodock tool. The acid dissociation constant (pKa) of oximes was calculated experimentally and drug-likeness properties of the oximes were calculated In silico using mole inspiration and Swiss ADME software. The binding of oximes with bovine serum albumin (BSA) was also investigated by UV-Vis spectrophotometer. The reactivation potential of the oximes was determined by in vitro enzymatic assay.

RESULT

in-silico study inferred that synthesized molecules fulfilled the parameters that required for a successful CNS drug candidate. Further, in-vitro enzymatic assay indicated reasonable reactivation potential of the oximes against paraoxon-inhibited AChE. The binding of oximes with bovine serum albumin (BSA) revealed static quenching of intrinsic fluorescence of BSA by oxime. The binding constant value and number of binding sites were found 0.24 mol-1 and 1 respectively.

CONCLUSION

The results of study concluded that this scaffold could be used for further designing of more efficient uncharged reactivators.