Biogenic Selenium Nanoparticles Attenuate Aβ(25-35)-Induced Toxicity in PC12 Cells via Akt/CREB/BDNF Signaling Pathway

Selenium metabolism and selenoproteins function in brain and encephalopathy

Selenium (Se) is an essential trace element of the utmost importance to human health. Its deficiency induces various disorders. Se species can be absorbed by organisms and metabolized to hydrogen selenide for the biosynthesis of selenoproteins, selenonucleic acids, or selenosugars. Se in mammals mainly acts as selenoproteins to exert their biological functions. The brain ranks highest in the specific hierarchy of organs to maintain the level of Se and the expression of selenoproteins under the circumstances of Se deficiency. Dyshomeostasis of Se and dysregulation of selenoproteins result in encephalopathy such as Alzheimer's disease, Parkinson's disease, depression, amyotrophic lateral sclerosis, and multiple sclerosis. This review provides a summary and discussion of Se metabolism, selenoprotein function, and their roles in modulating brain diseases based on the most currently published literature. It focuses on how Se is utilized and transported to the brain, how selenoproteins are biosynthesized and function physiologically in the brain, and how selenoproteins are involved in neurodegenerative diseases. At the end of this review, the perspectives and problems are outlined regarding Se and selenoproteins in the regulation of encephalopathy.

The Role of Gut Microbiota in the Neuroprotective Effects of Selenium in Alzheimer's Disease

The objective of the present review was to provide a timely update on the molecular mechanisms underlying the beneficial role of Se in Alzheimer's disease pathogenesis, and discuss the potential role of gut microbiota modulation in this neuroprotective effect. The existing data demonstrate that selenoproteins P, M, S, R, as well as glutathione peroxidases and thioredoxin reductases are involved in regulation of Aβ formation and aggregation, tau phosphorylation and neurofibrillary tangles formation, as well as mitigate the neurotoxic effects of Aβ and phospho-tau. Correspondingly, supplementation with various forms of Se in cellular and animal models of AD was shown to reduce Aβ formation, tau phosphorylation, reverse the decline in brain antioxidant levels, inhibit neuronal oxidative stress and proinflammatory cytokine production, improve synaptic plasticity and neurogenesis, altogether resulting in improved cognitive functions. In addition, most recent findings demonstrate that these neuroprotective effects are associated with Se-induced modulation of gut microbiota. In animal models of AD, Se supplementation was shown to improve gut microbiota biodiversity with a trend to increased relative abundance of Lactobacillus, Bifidobacterium, and Desulfivibrio, while reducing that of Lachnospiracea_NK4A136, Rikenella, and Helicobacter. Moreover, the relative abundance of Se-affected taxa was significantly associated with Aβ accumulation, tau phosphorylation, neuronal oxidative stress, and neuroinflammation, indicative of the potential role of gut microbiota to mediate the neuroprotective effects of Se in AD. Hypothetically, modulation of gut microbiota along with Se supplementation may improve the efficiency of the latter in AD, although further detailed laboratory and clinical studies are required.

Unravelling the in vitro and in vivo potential of selenium nanoparticles in Alzheimer's disease: A bioanalytical review

Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by progressive cognitive decline and the accumulation of beta-amyloid plaques and tau tangles in the brain. Current therapies have limited efficacy, prompting the search for novel treatments. Selenium nanoparticles (SeNPs) have emerged as promising candidates for AD therapy due to their unique physicochemical properties and potential therapeutic effects. This review provides an overview of SeNPs and their potential application in AD treatment, as well as the main bioanalytical techniques applied in this field. SeNPs possess antioxidant and anti-inflammatory properties, making them potential candidates to combat the oxidative stress and neuroinflammation associated with AD. Moreover, SeNPs have shown the ability to cross the blood-brain barrier (BBB), allowing them to target brain regions affected by AD pathology. Various methods for synthesizing SeNPs are explored, including chemical, physical and biological synthesis approaches. Based on the employment of algae, yeast, fungi, and plants, green methods offer a promising and biocompatible alternative for SeNPs production. In vitro studies have demonstrated the potential of SeNPs in reducing beta-amyloid aggregation and inhibiting tau hyperphosphorylation, providing evidence of their neuroprotective effects on neuronal cells. In vivo studies using transgenic mouse models and AD-induced symptoms have shown promising results, with SeNPs treatment leading to cognitive improvements and reduced amyloid plaque burden in the hippocampus. Looking ahead, future trends in SeNPs research involve developing innovative brain delivery strategies to enhance their therapeutic potential, exploring alternative animal models to complement traditional mouse studies, and investigating multi-targeted SeNPs formulations to address multiple aspects of AD pathology. Overall, SeNPs represent a promising avenue for AD treatment, and further research in this field may pave the way for effective and much-needed therapeutic interventions for individuals affected by this debilitating disease.

Ononin ameliorates depression-like behaviors by regulating BDNF-TrkB-CREB signaling in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Ononin is a flavonoid compound found in several medicinal plants, including Astragalus membranaceus, Sophora flavescens, and Ononis spinosa. These plants have been traditionally used in various parts of the world for their medicinal properties, including anti-inflammatory, antioxidant, and antitumor effects. Major depression is a common, long-lasting, and recurrent psychiatric disorder with a high suicide rate. Naturally occurring flavonoids treat depression via poorly understood mechanisms.

AIM OF THE STUDY

The present study aimed to determine whether ononin conferred an antidepressant-like effect in PC12 cell models and chronic mild stress (CMS)-induced depressive rat models and to explore its possible mechanisms.

MATERIALS AND METHODS

Depression-related behaviors were measured using sucrose preference, tail suspension and open-field tests. Furthermore, to explore these mechanisms, we employed in vitro and in vivo assay methods, including neurite outgrowth, western blotting, quantitative RT-PCR, and staining methods.

RESULTS

Treatment with ononin or BDNF significantly increased PC12 cells' neuronal growth and differentiation. Furthermore, ononin promotes the activation of TrkB and growth factors and upregulates the PI3K/Akt and BDNF/TrkB/CREB signaling pathways. The in vitro results were consistent with CMS-induced depressive rat models, in which ononin treatment significantly decreased depression-like behaviors and activated TrkB, growth factors, and BDNF/TrkB/CREB signaling pathways in the frontal cortex and hippocampus. Depression-induced microscopic alterations in the frontal cortex and hippocampus of rats with CMS-induced depression were also mitigated following ononin treatment.

CONCLUSION

Based on these findings, we suggest that ononin is a promising antidepressant candidate for treating depression.

Notoginsenoside R1 ameliorates the inflammation induced by amyloid‑β by suppressing SphK1‑mediated NF‑κB activation in PC12 cells

Alzheimer's disease (AD) is the most common type of age‑related dementia, and causes progressive memory degradation, neuronal loss and brain atrophy. The pathological hallmarks of AD consist of amyloid‑β (Aβ) plaque accumulation and abnormal neurofibrillary tangles. Amyloid fibrils are constructed from Aβ peptides, which are recognized to assemble into toxic oligomers and exert cytotoxicity. The fibrillar Aβ‑protein fragment 25‑35 (Aβ25‑35) induces local inflammation, thereby exacerbating neuronal apoptosis. Notoginsenoside R1 (NGR1), one of the primary bioactive ingredients isolated from Panax notoginseng, exhibits effective anti‑inflammatory and anti‑oxidative activities. However, NGR1 pharmacotherapies targeting Aβ‑induced inflammation and cell injury cascade remain to be elucidated. The present study investigated the effect and mechanism of NGR1 in Aβ25‑35‑treated PC12 cells. NGR1 doses between 250 and 1,000 µg/ml significantly increased cell viability suppressed by 20 µM Aβ25‑35 peptide treatment. Notably, the present study demonstrated that Aβ25‑35 peptide‑induced sphingosine kinase 1 (SphK1) signaling activation was reduced after NGR1 treatment, further inhibiting the downstream NF‑κB inflammatory signaling pathway. In addition, administration of SphK1 inhibitor II (SKI‑II), a SphK1 inhibitor, also significantly reduced Aβ25‑35 peptide‑induced apoptosis and the ratio of NF‑κB p‑p65/p65. Furthermore, SphK1 knockdown in PC12 cells using small interfering RNA alleviated Aβ‑induced cell apoptosis and inflammation, suggesting a pivotal role of SphK1 signaling in the anti‑inflammatory effect of NGR1. In summary, NGR1 alleviated inflammation and apoptosis stimulated by Aβ25‑35 by inhibiting the SphK1/NF‑κB signaling pathway and may be a promising agent for future AD treatment.

Revisiting the Role of Vitamins and Minerals in Alzheimer's Disease

Alzheimer's disease (AD) is the most common type of dementia that affects millions of individuals worldwide. It is an irreversible neurodegenerative disorder that is characterized by memory loss, impaired learning and thinking, and difficulty in performing regular daily activities. Despite nearly two decades of collective efforts to develop novel medications that can prevent or halt the disease progression, we remain faced with only a few options with limited effectiveness. There has been a recent growth of interest in the role of nutrition in brain health as we begin to gain a better understanding of what and how nutrients affect hormonal and neural actions that not only can lead to typical cardiovascular or metabolic diseases but also an array of neurological and psychiatric disorders. Vitamins and minerals, also known as micronutrients, are elements that are indispensable for functions including nutrient metabolism, immune surveillance, cell development, neurotransmission, and antioxidant and anti-inflammatory properties. In this review, we provide an overview on some of the most common vitamins and minerals and discuss what current studies have revealed on the link between these essential micronutrients and cognitive performance or AD.