Selegiline (L-Deprenyl) Mitigated Oxidative Stress, Cognitive Abnormalities, and Histopathological Change in Rats: Alternative Therapy in Transient Global Ischemia

Protective effects of cedrol against transient global cerebral ischemia/reperfusion injury in rat

BACKGROUND

The natural compound cedrol possess anti-inflammatory and antioxidant properties. We sought to assess the neuroprotective effect of cedrol in an animal model of transient global ischemia/reperfusion (I/R) injury.

METHOD

To induce transient global cerebral I/R injury, bilateral carotid arteries were temporarily occluded for 20 min. A total of 40 male Wistar rats were randomly divided in to 5 groups; The control and global I/R groups, and the treatment groups that received cedrol at doses of 7.5, 15, and 30 mg/kg/day for a week, following the global I/R induction. The passive avoidance test was used for assessing memory function, and then hippocampal tissues were collected to assess levels of malondialdehyde (MDA), total thiol, nitric oxide (NO), and the activity of superoxide dismutase (SOD), along with the concentration of brain-derived neurotrophic factor (BDNF).

RESULT

Our findings revealed that global I/R injury impaired rats' performance in the passive avoidance test and increased levels of MDA and NO. Moreover, it decreased the total thiol level, SOD activity, and BDNF level in the hippocampus. Administration of cedrol significantly improved memory function, reduced oxidative stress, NO level and increased BDNF level in the hippocampus.

CONCLUSION

The results indicate that cedrol has neuroprotective properties in global I/R by reducing oxidative stress and enhancing the levels of BDNF.

Selegiline Improves Cognitive Impairment in the Rat Model of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurological disorder characterized by cognitive decline. This study was undertaken to evaluate the effects of selegiline (SEL) against AD-induced cognitive deficits and explore the possible involved mechanisms. AD was induced by unilateral intracerebroventricular (U-ICV) injection of 5 μg of amyloid beta1-42 (Aβ1-42), and oral administration of SEL (0.5 mg/kg/day) was performed for 30 consecutive days. Aβ injection resulted in spatial cognitive decline, as demonstrated by a decrease in the time spent in the target zone on the probe day (P < 0.01) in the Barnes maze test (BMT). This spatial cognitive decline was associated with disrupted synaptic plasticity, as indicated by reductions in both components of hippocampal long-term potentiation (LTP), namely population spike amplitude (P < 0.001) and field excitatory postsynaptic potential (P < 0.001). On the other hand, the injection of Aβ resulted in oxidative stress by decreasing total thiol group (TTG) content and increasing malondialdehyde (MDA) levels in the rat plasma (P < 0.001). Additionally, the number of healthy cells in the hippocampal dentate gyrus (DG) and CA1 regions was reduced in AD rats (P < 0.001). However, oral administration of SEL improved spatial cognitive decline in the Aβ-induced AD rats. The results suggest that improvement of neuroplasticity deficiency, regulation of oxidant/antioxidant status, and suppression of neuronal loss by SEL may be the mechanisms underlying its beneficial effect against AD-related spatial cognitive impairment.

Targeting MAO-B with Small-Molecule Inhibitors: A Decade of Advances in Anticancer Research (2012-2024)

Monoamine oxidase B (MAO-B) is a key enzyme in the mitochondrial outer membrane, pivotal for the oxidative deamination of biogenic amines. Its overexpression has been implicated in the pathogenesis of several cancers, including glioblastoma and colorectal, lung, renal, and bladder cancers, primarily through the increased production of reactive oxygen species (ROS). Inhibition of MAO-B impedes cell proliferation, making it a potential therapeutic target. Various monoamine oxidase B inhibitors have shown promise in inhibiting tumor growth and inducing apoptosis across different cancer types. In this review, we investigate MAO-B network biology, which highlighted glycolysis pathways as notable links between MAO-B and cancer. Further molecular modeling analysis illustrated the basis of MAO-B ligand binding, revealing a hydrophobic binding pocket, with key residues such as Tyr398 and Tyr435 playing crucial roles in substrate oxidation. MAO-B inhibitors that were reportsed in the literature (2012-2024) and their potential application in cancer therapy were discussed, highlighting key molecular scaffolds, such as propargyl analogs of phenyl alkyl amines, hydrazine derivatives, cyclopropylamine derivatives, MAO-B activated pro-drugs, and natural phenylpropanoid derivatives. The reported literature underscores the therapeutic potential of MAO-B inhibitors as versatile anticancer agents, warranting further investigation to optimize their efficacy and specificity across various malignancies.

The role of gender differences in the outcome of juvenile social isolation: Emphasis on changes in behavioral, biochemical and expression of nitric oxide synthase genes alteration

Social isolation can cause serious problem in performance of individuals in community. As gender differences may cause variation results in the severity of depressive behavior and response of patients to therapy, the impact of gender and the interaction of the level of endocrine secretion in depression were investigated in this study. Wistar rats of both sexes were subjected to post-weaning social isolation (PWSI) conditions and, together with the control group, experienced several behavioral tests including open-field Test (OFT), elevated plus maze (EPM), force swimming test (FST), splash test and novel object recognition test (NOR). Hippocampal tissue was isolated to measure biochemical factors such as nitric oxide level, FRAP amount, MDA level. In addition, real-time-PCR test was used to quantify the genes expression level of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS). On the other hand, sexual hormone levels in blood were measured. Both cognitive and behavioral f unctions were declined as the result of PWSI induction in male and diestrus female rats. The consequent surge of estradiol during estrous phase seems to suppress the accumulation of reactive oxygen species (ROS), and modulate iNOS and nNOS expression. In conclusion, while the pattern of PWSI in surge cellular antioxidants, raising cellular ROS level is gender-specific, this alleviation was in relation with the drop of estradiol and unrelated with testosterone level.

Liposome Nanocarriers Based on γ Oryzanol: Preparation, Characterization, and In Vivo Assessment of Toxicity and Antioxidant Activity

The present study aimed to develop and characterize liposome nanocarriers based on γ oryzanol and evaluate their potential in vitro and in vivo toxicity and antioxidant effects. The liposomes were physicochemically characterized using various techniques, including dynamic light scattering (DLS) for size and polydispersity index (PDI) measurements and ζ-potential analysis. The in vitro toxicity assessments were performed using hemolysis and MTT assays on the HS5 cell line. In vivo, acute oral toxicity was evaluated by using LD50 assays in mice. Additionally, antioxidant activity was assessed through biochemical analysis of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and liver tissue catalase, malondialdehyde (MDA), and glutathione (GSH) levels. The results revealed that the liposomes exhibited a uniform and spherical morphology with suitable physicochemical properties for drug delivery applications. The in vitro cytotoxicity and hemolysis assays and the in vivo LD50 experiment indicated the potential safety of γ oryzanol liposomes, especially at lower concentrations. In addition, the assessment of liver enzymes, i.e., ALT and AST, and the antioxidant markers further revealed the safety of the formulation, particularly for the liver as a highly sensitive soft organ. Overall, the liposome nanocarriers based on γ oryzanol were successfully formulated and expressed potential safety, supporting their application for the purposes of drug delivery and therapeutic interventions, particularly for hepatocellular and antioxidant therapies; however, further investigations for preclinical and clinical studies could be the future prospects for liposome nanocarriers based on γ oryzanol to explore the safety and efficacy of these nanocarriers in various disease models and clinical settings.

Type-B monoamine oxidase inhibitors in neurological diseases: clinical applications based on preclinical findings

Type-B monoamine oxidase inhibitors, encompassing selegiline, rasagiline, and safinamide, are available to treat Parkinson's disease. These drugs ameliorate motor symptoms and improve motor fluctuation in the advanced stages of the disease. There is also evidence supporting the benefit of type-B monoamine oxidase inhibitors on non-motor symptoms of Parkinson's disease, such as mood deflection, cognitive impairment, sleep disturbances, and fatigue. Preclinical studies indicate that type-B monoamine oxidase inhibitors hold a strong neuroprotective potential in Parkinson's disease and other neurodegenerative diseases for reducing oxidative stress and stimulating the production and release of neurotrophic factors, particularly glial cell line-derived neurotrophic factor, which support dopaminergic neurons. Besides, safinamide may interfere with neurodegenerative mechanisms, counteracting excessive glutamate overdrive in basal ganglia motor circuit and reducing death from excitotoxicity. Due to the dual mechanism of action, the new generation of type-B monoamine oxidase inhibitors, including safinamide, is gaining interest in other neurological pathologies, and many supporting preclinical studies are now available. The potential fields of application concern epilepsy, Duchenne muscular dystrophy, multiple sclerosis, and above all, ischemic brain injury. The purpose of this review is to investigate the preclinical and clinical pharmacology of selegiline, rasagiline, and safinamide in Parkinson's disease and beyond, focusing on possible future therapeutic applications.

Enhancing the Neuroprotection Potential of Edaravone in Transient Global Ischemia Treatment with Glutathione- (GSH-) Conjugated Poly(methacrylic acid) Nanogel as a Promising Carrier for Targeted Brain Drug Delivery

Ischemic stroke is the most common among various stroke types and the second leading cause of death, worldwide. Edaravone (EDV) is one of the cardinal antioxidants that is capable of scavenging reactive oxygen species, especially hydroxyl molecules, and has been already used for ischemic stroke treatment. However, poor water solubility, low stability, and bioavailability in aqueous media are major EDV drawbacks. Thus, to overcome the aforementioned drawbacks, nanogel was exploited as a drug carrier of EDV. Furthermore, decorating the nanogel surface with glutathione as targeting ligands would potentiate the therapeutic efficacy. Nanovehicle characterization was assessed with various analytical techniques. Size (199 nm, hydrodynamic diameter) and zeta potential (-25 mV) of optimum formulation were assessed. The outcome demonstrated a diameter of around 100 nm, sphere shape, and homogenous morphology. Encapsulation efficiency and drug loading were determined to be 99.9% and 37.5%, respectively. In vitro drug release profile depicted a sustained release process. EDV and glutathione presence in one vehicle simultaneously made the possibility of antioxidant effects on the brain in specific doses, which resulted in elevated spatial memory and learning along with cognitive function in Wistar rats. In addition, significantly lower MDA and PCO and higher levels of neural GSH and antioxidant levels were observed, while histopathological improvement was approved. The developed nanogel can be a suited vehicle for drug delivery of EDV to the brain and improve ischemia-induced oxidative stress cell damage.

S-Glutathionylation and S-Nitrosylation in Mitochondria: Focus on Homeostasis and Neurodegenerative Diseases

Redox post-translational modifications are derived from fluctuations in the redox potential and modulate protein function, localization, activity and structure. Amongst the oxidative reversible modifications, the S-glutathionylation of proteins was the first to be characterized as a post-translational modification, which primarily protects proteins from irreversible oxidation. However, a growing body of evidence suggests that S-glutathionylation plays a key role in core cell processes, particularly in mitochondria, which are the main source of reactive oxygen species. S-nitrosylation, another post-translational modification, was identified >150 years ago, but it was re-introduced as a prototype cell-signaling mechanism only recently, one that tightly regulates core processes within the cell’s sub-compartments, especially in mitochondria. S-glutathionylation and S-nitrosylation are modulated by fluctuations in reactive oxygen and nitrogen species and, in turn, orchestrate mitochondrial bioenergetics machinery, morphology, nutrients metabolism and apoptosis. In many neurodegenerative disorders, mitochondria dysfunction and oxidative/nitrosative stresses trigger or exacerbate their pathologies. Despite the substantial amount of research for most of these disorders, there are no successful treatments, while antioxidant supplementation failed in the majority of clinical trials. Herein, we discuss how S-glutathionylation and S-nitrosylation interfere in mitochondrial homeostasis and how the deregulation of these modifications is associated with Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis and Friedreich’s ataxia.

Role of Nrf2 in aging, Alzheimer's and other neurodegenerative diseases

Nuclear Factor-Erythroid Factor 2 (Nrf2) is an important transcription factor that regulates the expression of large number of genes in healthy and disease states. Nrf2 is made up of 605 amino acids and contains 7 conserved regions known as Nrf2-ECH homology domains. Nrf2 regulates the expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy and mitochondrial function in all organs of the human body, in the peripheral and central nervous systems. Mounting evidence also suggests that altered expression of Nrf2 is largely involved in aging, neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's diseases, Amyotrophic lateral sclerosis, Stroke, Multiple sclerosis and others. The purpose of this article is to detail the essential role of Nrf2 in oxidative stress, antioxidative defense, detoxification, inflammatory responses, transcription factors, proteasomal and autophagic/mitophagic degradation, and metabolism in aging and neurodegenerative diseases. This article also highlights the Nrf2 structural and functional activities in healthy and disease states, and also discusses the current status of Nrf2 research and therapeutic strategies to treat aging and neurodegenerative diseases.

Biogenic and facile synthesis of selenium nanoparticles using Vaccinium arctostaphylos L. fruit extract and anticancer activity against in vitro model of breast cancer

Biogenic synthesis of selenium nanoparticles (SeNPs) using plant extracts has emerged as a promising alternative approach to traditional chemical synthesis. The current study aims to introduce a safe, low-cost, and green synthesis of SeNPs using fresh fruit extract of Vaccinium arctostaphylos L. The biogenic synthesis of SeNPs was confirmed by different analyses including ultraviolet-visible spectrophotometry, Fourier transform infrared, and energy-dispersive X-ray. Also, the crystalline nature, size, and morphology of the obtained SeNPs were characterized by X-ray diffraction, dynamic light scattering, field emission scanning electron microscopy, and transmission electron microscopy techniques. The SeNPs were successfully synthesized with fruit extract of V. arctostaphylos L. in a regular spherical form and narrow size distribution with suitable zeta-potential values and exhibited appropriate biocompatibility. It revealed that the synthesized SeNPs can significantly inhibit the growth of 4T1 breast cancer cells with an IC₅₀ of ∼84.19 ± 25.96 µg/ml after 72 h treatment. Overall, it can be concluded that the green synthesized SeNPs can be attractive, nontoxic, and eco-friendly candidates for drug delivery or medicinal applications.

Modulation of Reactive Oxygen Species Homeostasis as a Pleiotropic Effect of Commonly Used Drugs

Age-associated diseases represent a growing burden for global health systems in our aging society. Consequently, we urgently need innovative strategies to counteract these pathological disturbances. Overwhelming generation of reactive oxygen species (ROS) is associated with age-related damage, leading to cellular dysfunction and, ultimately, diseases. However, low-dose ROS act as crucial signaling molecules and inducers of a vaccination-like response to boost antioxidant defense mechanisms, known as mitohormesis. Consequently, modulation of ROS homeostasis by nutrition, exercise, or pharmacological interventions is critical in aging. Numerous nutrients and approved drugs exhibit pleiotropic effects on ROS homeostasis. In the current review, we provide an overview of drugs affecting ROS generation and ROS detoxification and evaluate the potential of these effects to counteract the development and progression of age-related diseases. In case of inflammation-related dysfunctions, cardiovascular- and neurodegenerative diseases, it might be essential to strengthen antioxidant defense mechanisms in advance by low ROS level rises to boost the individual ROS defense mechanisms. In contrast, induction of overwhelming ROS production might be helpful to fight pathogens and kill cancer cells. While we outline the potential of ROS manipulation to counteract age-related dysfunction and diseases, we also raise the question about the proper intervention time and dosage.

Mitigated Oxidative Stress and Cognitive Impairments in Transient Global Ischemia using Niosomal Selegiline-NBP delivery

Stroke is the most common reason for adult disabilities and the second ground for death worldwide. Our previous study revealed that selegiline serves as an alternative candidate in transient hypoxia-ischemia. However, aggressive and restless behavior was observed in stroke-induced rats receiving 4 mg/kg selegiline. In comparison, 1 mg/kg selegiline could induce negligible therapeutic effects on mitochondrial dysfunction and histopathological changes. Therefore, we designed oral noisome-based selegiline attached to 4-(4-nitrobenzyl) pyridine to improve transient global ischemia by attenuating cognitive impairments, oxidative stress, and histopathological injury. The investigation was performed in transient hypoxia-ischemia-induced rats by oral administration of nanoformulation containing selegiline (0.25-1 mg/kg) for 4 weeks (3 times a week). Novel object recognition (NOR) was considered to evaluate their cognitive dysfunction. Oxidative stress parameters and brain histopathological assessments were determined following the scarification of rats. Outstandingly, our data demonstrated slower selegiline release from niosomes relative to free drug, which was also in a controlled manner. Our data confirmed significant improvement in cognitive behavior in the NOR test, an increase in glutathione level and total antioxidant power, a decline in MDA and protein carbonyl level, as well as a decreased number of dead cells in histopathological assessment after being exposed to (0.5-1 mg/kg) selegiline-NBP nanoformulation. These data manifested that the selegiline-NBP nanoformulation (0.5-1 mg/kg) could significantly reduce oxidative damage, cognitive dysfunction, and histopathological damage compared to transient hypoxia-ischemia rats, which is 20 times lower than the therapeutic dose in humans. Therefore, the proposed nanoformulation would be capable as an alternative candidate without side effects in stroke.

The Nrf2 Pathway in Ischemic Stroke: A Review

Ischemic stroke, characterized by the sudden loss of blood flow in specific area(s) of the brain, is the leading cause of permanent disability and is among the leading causes of death worldwide. The only approved pharmacological treatment for acute ischemic stroke (intravenous thrombolysis with recombinant tissue plasminogen activator) has significant clinical limitations and does not consider the complex set of events taking place after the onset of ischemic stroke (ischemic cascade), which is characterized by significant pro-oxidative events. The transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates the expression of a great number of antioxidant and/or defense proteins, has been pointed as a potential pharmacological target involved in the mitigation of deleterious oxidative events taking place at the ischemic cascade. This review summarizes studies concerning the protective role of Nrf2 in experimental models of ischemic stroke, emphasizing molecular events resulting from ischemic stroke that are, in parallel, modulated by Nrf2. Considering the acute nature of ischemic stroke, we discuss the challenges in using a putative pharmacological strategy (Nrf2 activator) that relies upon transcription, translation and metabolically active cells in treating ischemic stroke patients.

Redox Post-translational Modifications of Protein Thiols in Brain Aging and Neurodegenerative Conditions-Focus on S-Nitrosation

Reactive oxygen species and reactive nitrogen species (RONS) are by-products of aerobic metabolism. RONS trigger a signaling cascade that can be transduced through oxidation-reduction (redox)-based post-translational modifications (redox PTMs) of protein thiols. This redox signaling is essential for normal cellular physiology and coordinately regulates the function of redox-sensitive proteins. It plays a particularly important role in the brain, which is a major producer of RONS. Aberrant redox PTMs of protein thiols can impair protein function and are associated with several diseases. This mini review article aims to evaluate the role of redox PTMs of protein thiols, in particular S-nitrosation, in brain aging, and in neurodegenerative diseases. It also discusses the potential of using redox-based therapeutic approaches for neurodegenerative conditions.