Osthole promotes neuronal differentiation and inhibits apoptosis via Wnt/β-catenin signaling in an Alzheimer's disease model

Plant natural product-based pesticides in crop protection: semi-synthesis, mono-crystal structures and agrochemical activities of osthole ester derivatives, and study of their toxicology against Tetranychus cinnabarinus (Boisduval)

BACKGROUND

Owing to large amounts of synthetic pesticides being extensively and unreasonably used for crop protection, currently, resistance and negative impacts on human health and environment safety have appeared. Therefore, development of potential pesticide candidates is highly urgent. Herein, a series of ester derivatives of osthole were designed and synthesized as pesticidal agents.

RESULTS

Six spatial configurations of 4'-(p-toluenoyloxy)osthole (4b), 4'-(m-fluorobenzoyloxy)osthole (4f), 4'-(p-fluorophenylacetyloxy)osthole (4m), 4'-(3'',4''-methylenedioxybenzoyloxy)osthole (4q), 4'-formyloxyosthole (4u) and 4'-acetyloxyosthole (4v) were determined by X-ray mono-crystal diffraction. Compounds 4b, 4'-(p-chlorobenzoyloxy)osthole (4g), 4'-(m-chlorobenzoyloxy)osthole (4h), 4'-(p-bromobenzoyloxy)osthole (4i) and 4'-(2''-chloropyridin-3''-ylcarbonyloxy)osthole (4p) showed higher insecticidal activity than toosendanin against Mythimna separata Walker; notably, compound 4b displayed 1.8 times insecticidal activity of the precursor osthole. Against Tetranychus cinnabarinus Boisduval, compounds 4g and 4h showed 3.3 and 2.6 times acaricidal activity of osthole, and good control effects in the glasshouse. Scanning electron microscopy assay demonstrated that compound 4g can damage the cuticle layer of T. cinnabarinus resulting in death.

CONCLUSION

Compounds 4g and 4h can be further studied as lead pesticidal agents for the management of M. separata and T. cinnabarinus. These results will pave the way for application of osthole derivatives as agrochemicals. © 2024 Society of Chemical Industry.

Unlocking Hope: Therapeutic Advances and Approaches in Modulating the Wnt Pathway for Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are conditions characterized by sensory, motor, and cognitive impairments due to alterations in the structure and function of neurons in the central nervous system (CNS). Despite their widespread occurrence, the exact causes of NDs remain largely elusive, and existing treatments fall short in efficacy. The Wnt signaling pathway is an emerging molecular pathway that has been linked to the development and progression of various NDs. Wnt signaling governs numerous cellular processes, such as survival, polarity, proliferation, differentiation, migration, and fate specification, via a complex network of proteins. In the adult CNS, Wnt signaling regulates synaptic transmission, plasticity, memory formation, neurogenesis, neuroprotection, and neuroinflammation, all essential for maintaining neuronal function and integrity. Dysregulation of both canonical and non-canonical Wnt signaling pathways contributes to neurodegeneration through various mechanisms, such as amyloid-β accumulation, tau protein hyperphosphorylation, dopaminergic neuron degeneration, and synaptic dysfunction, prompting investigations into Wnt modulation as a therapeutic target to restore neuronal function and prevent or delay neurodegenerative processes. Modulating Wnt signaling has the potential to restore neuronal function and impede or postpone neurodegenerative processes, offering a therapeutic approach for targeting NDs. In this article, the current knowledge about how Wnt signaling works in Alzheimer's disease and Parkinson's disease is discussed. Our study aims to explore the molecular mechanisms, recent discoveries, and challenges involved in developing Wnt-based therapies.

Exploring the Therapeutic Potential of BBB-Penetrating Phytochemicals With p38 MAPK Modulatory Activity in Addressing Oxidative Stress-Induced Neurodegenerative Disorders, With a Focus on Alzheimer's Disease

Oxidative stress plays an important role in the occurrence of neurodegenerative diseases. Previous studies indicate a strong connection between oxidative stress, inappropriate activation of the p38 MAPK signaling pathway, and the pathogenesis of neurodegenerative diseases. Although antioxidant therapy is a valid strategy to alleviate these problems, the most important limitation of this approach is the ineffectiveness of drug administration due to the limited permeability of the BBB. Therefore, BBB-penetrating p38 MAPK modulators with proper antioxidant capacity could be useful in preventing/reducing the complications of neurodegenerative disorders. The current manuscript aims to review the therapeutic capabilities of some recently reviewed naturally occurring p38 MAPK inhibitors in the management of neurodegenerative problems such as Alzheimer's disease. In data collection, we tried to use more recent studies published in high-quality journals indexed in databases Scopus, Web of Science, PubMed, and so on, but no specific time frame was considered due to the nature of the study. Our evaluations indicate that natural compounds tanshinones, protoberberines, pinocembrin, osthole, rhynchophylline, oxymatrine, schisandrin, piperine, paeonol, ferulic acid, 6-gingerol, obovatol, and trolox have significant potential for use as supplements/adjuvants in the reduction of neurodegenerative-related problems. Our findings emphasize the usefulness of BBB-penetrating phytochemicals with p38 MAPK modulatory activity as potential therapeutic options against neurodegenerative disorders. Of course, the proper use of these compounds depends on considering their toxicity/safety profile and pharmacokinetic characteristics as well as the clinical conditions of users.

Signaling Pathways Involved in the Neuroprotective Effect of Osthole: Evidence and Mechanisms

Neurodegenerative diseases constitute a major threat to human health and are usually accompanied by progressive structural and functional loss of neurons. Abnormalities in synaptic plasticity are involved in neurodegenerative disorders. Aberrant cell signaling cascades play a predominant role in the initiation, progress as well as in the severity of these ailments. Notch signaling is a pivotal role in the maintenance of neural stem cells and also participates in neurogenesis. PI3k/Akt cascade regulates different biological processes including cell proliferation, apoptosis, and metabolism. It regulates neurotoxicity and mediates the survival of neurons. Moreover, the activated BDNF/TrkB cascade is involved in promoting the transcription of genes responsible for cell survival and neurogenesis. Despite significant progress made in delineating the underlying pathological mechanisms involved and derangements in cellular metabolic promenades implicated in these diseases, satisfactory strategies for the clinical management of these ailments are yet to be achieved. Therefore, the molecules targeting these cell signaling cascades may emerge as useful leads in developing newer management strategies. Osthole is an important ingredient of traditional Chinese medicinal plants, often found in various plants of the Apiaceae family and has been observed to target these aforementioned mediators. Until now, no review has been aimed to discuss the possible molecular signaling cascades involved in osthole-mediated neuroprotection at one platform. The current review aimed to explore the interplay of various mediators and the modulation of the different molecular signaling cascades in osthole-mediated neuroprotection. This review could open new insights into research involving diseases of neuronal origin, especially the effect on neurodegeneration, neurogenesis, and synaptic plasticity. The articles gathered to compose the current review were extracted by using the PubMed, Scopus, Science Direct, and Web of Science databases. A methodical approach was used to integrate and discuss all published original reports describing the modulation of different mediators by osthole to confer neuroprotection at one platform to provide possible molecular pathways. Based on the inclusion and exclusion criteria, 32 articles were included in the systematic review. Moreover, literature evidence was also used to construct the biosynthetic pathway of osthole. The current review reveals that osthole promotes neurogenesis and neuronal functioning via stimulation of Notch, BDNF/Trk, and P13k/Akt signaling pathways. It upregulates the expression of various proteins, such as BDNF, TrkB, CREB, Nrf-2, P13k, and Akt. Activation of Wnt by osthole, in turn, regulates downstream GSK-1β to inhibit tau phosphorylation and β-catenin degradation to prevent neuronal apoptosis. The activation of Wnt and inhibition of oxidative stress, Aβ, and GSK-3β mediated β-catenin degradation by osthole might also be involved in mediating the protection against neurodegenerative diseases. Furthermore, it also inhibits neuroinflammation by suppressing MAPK/NF-κB-mediated transcription of genes involved in the generation of inflammatory cytokines and NLRP-3 inflammasomes. This review delineates the various underlying signaling pathways involved in mediating the neuroprotective effect of osthole. Modulation of Notch, BDNF/Trk, MAPK/NF-κB, and P13k/Akt signaling pathways by osthole confers protection against neurodegenerative diseases. The preclinical effects of osthole suggest that it could be a valuable molecule in inspiring the development of new drugs for the management of neurodegenerative diseases and demands clinical studies to explore its potential. An effort has been made to unify the varied mechanisms and target sites involved in the neuroprotective effect of osthole. The comprehensive description of the molecular pathways in the present work reflects its originality and thoroughness. The reviewed literature findings may be extrapolated to suggest the role of othole as a "biological response modifier" which contributes to neuroprotection through kinase modulatory, immunomodulatory, and anti-oxidative activity, which is documented even at lower doses. The current review attempts to emphasize the gaps in the existing literature which can be explored in the future.

Network Proximity Analysis Deciphers the Pharmacological Mechanism of Osthole against D-Galactose Induced Cognitive Disorder in Rats

Osthole, a natural coumarin found in various medicinal plants, has been previously reported to have neuroprotective effects. However, the specific mechanism by which Osthole alleviates dysmnesia associated with Alzheimer's disease (AD) remains unclear. This study aimed to investigate the neuroprotective properties of Osthole against cognitive impairment in rats induced by D-galactose and elucidate its pharmacological mechanism. The rat model was established by subcutaneously injecting D-galactose at a dose of 150 mg/kg/day for 56 days. The effect of Osthole on cognitive impairment was evaluated by behavior and biochemical analysis. Subsequently, a combination of in silico prediction and experimental validation was performed to verify the network-based predictions, using western blot, Nissl staining, and immunofluorescence. The results demonstrate that Osthole could improve memory dysfunction induced by D-galactose in Sprague Dawley male rats. A network proximity-based approach and integrated pathways analysis highlight two key AD-related pathological processes that may be regulated by Osthole, including neuronal apoptosis, i.e., neuroinflammation. Among them, the pro-apoptotic markers (Bax), anti-apoptotic protein (Bcl-2), the microgliosis (Iba-1), Astro-cytosis (GFAP), and inflammatory cytokines (TNF-R1) were evaluated in both hippocampus and cortex. The results indicated that Osthole significantly ameliorated neuronal apoptosis and neuroinflammation in D-galactose-induced cognitive impairment rats. In conclusion, this study sheds light on the pharmacological mechanism of Osthole in mitigating D-galactose-induced memory impairment and identifies Osthole as a potential drug candidate for AD treatment, targeting multiple signaling pathways through network proximity and integrated pathways analysis.

Osthole Antagonizes Microglial Activation in an NRF2-Dependent Manner

Microglia are neuroglia in the brain with an innate immune function and participate in the progress of neurodegenerative diseases. Osthole (OST) is a coumarin derivative extracted from Cnidium monnieri and bears a microglia-antagonizing ability. However, the underlying mechanism of the antagonism is not clear. The lipopolysaccharides-induced microglial BV2 cell line and amyloid-overexpressing fruit fly were used as models to study OST treatment. We found that OST treatment is sufficient to evoke NRF2 cascade under an LPS-induced inflammatory environment, and silencing NRF2 is sufficient to abolish the process. Moreover, we found that OST is sufficient to antagonize microglial activation in both LPS-induced BV2 cells and Aβ-overexpressing fruit flies, and silencing NRF2 abolishes OST's antagonism. Furthermore, OST treatment rescued survival, climbing, and the learning ability of Aβ-overexpressing fruit flies and relieved oxidative stress. In conclusion, we proved that OST antagonizes microglial activation induced by either LPS or Aβ and that NRF2 is necessary for OST's antagonism.

Epigenetic signature in neural plasticity: the journey so far and journey ahead

Neural plasticity is a remarkable characteristic of the brain which allows neurons to rewire their structure in response to internal and external stimuli. Many external stimuli collectively referred to as 'epigenetic factors' strongly influence structural and functional reorganization of the brain, thereby acting as a potential driver of neural plasticity. DNA methylation and demethylation, histone acetylation, and deacetylation are some of the frontline epigenetic mechanisms behind neural plasticity. Epigenetic signature molecules (mostly proteins) play a pivotal role in epigenetic reprogramming. Though neuro-epigenetics is an incredibly important field of emerging research, the critical role of signature proteins associated with epigenetic alteration and their involvement in neural plasticity needs further attention. This study gives an integrated and systematic overview of the current state of knowledge with a clear idea of types of neural plasticity and the context-dependent role of epigenetic signature molecules and their modulation by some natural bioactive compounds.

Ginsenoside Rg1 improves Alzheimer's disease by regulating oxidative stress, apoptosis, and neuroinflammation through Wnt/GSK-3β/β-catenin signaling pathway

Alzheimer's disease (AD) is a chronic neurodegenerative disorder that can cause cognitive impairment. Ginsenoside Rg1 (Rg1) has a significant neuroprotective effect on animals with memory impairment. However, the mechanism of how Rg1 mediates the Wnt signaling pathway and improves cognitive function by regulating oxidative stress, apoptosis, and neuroinflammation is still unclear. In this study, the spatial memory ability of tree shrews was tested by Morris water maze, the expression levels of amyloid protein (Aβ1-42), ionized calcium-binding adapter molecule 1 (iba-1), nitrotyrosine (NT), and 8-hydroxyguanine (8-OHG) were detected by immunohistochemistry. Subsequently, the activity of catalase (CAT) and the glutathione peroxidase (GSH-Px) was, respectively, measured by the ammonium molybdate method and the 5,5'-dithiobis (2-nitrobenzoic acid). Furthermore, the malondialdehyde (MDA) concentration was determined by the thiobarbituric acid test. Finally, the expression levels of Beta-secretase (BACE1), superoxide dismutase (SOD), BCL2-Associated X (Bax), B-cell lymphoma-2 (Bcl-2), caspase-anti-apoptotic factor Cleaved-caspase-3 (Caspase-3), microtubule-associated proteins 2 (MAP2), Neuronal nuclear antigen (NeuN), as well as the phosphorylation of GSK-3β and β-catenin were detected by Western blot. This study implied that Rg1 reduced the phosphorylation of Tau protein, the deposition of Aβ1-42, and the expression of BACE1. It also showed that Rg1 increased the antioxidant activity of SOD, CAT, GPx, and instead reduced the oxidation products of NT, 8-OHG, and MDA, as wells as the inflammatory factor interleukin-1 and iba-1. It further showed that Rg1 increased the ratio of Bcl-2 to Bax and expression of neuronal markers MAP2 and NeuN, but instead reduced the expression of Caspase-3, GSK-3β, and β-catenin. In conclusion, by regulating the Wnt/GSK-3β/β-catenin signaling pathway, Rg1 of moderate and high dose could alleviate oxidative stress damage, improve neuroinflammation, protect neurons, finally improve the cognitive impairment of the AD tree shrew. This study provides theoretical basis for the Rg1 clinical application in AD.

Dendrobium nobile Lindl. Alkaloids Ameliorate Aβ25-35-Induced Synaptic Deficits by Targeting Wnt/β-Catenin Pathway in Alzheimer’s Disease Models

Background: Dendrobium nobile Lindl. alkaloids (DNLA) are effective in ameliorating cognitive deficit in SAMP8, AβPP/PS1, and LPS-induced AD animal models, and prevented Aβ-induced synaptic degeneration in cultured hippocampal neurons. However, the underlying mechanisms remain unexplored. Objective: This study investigated the protective effects of DNLA on synaptic damage in an Aβ 25-35-induced rat AD model, in primary cortical neuron cultures, and in PC12 cells transfected with human AβPP695, focusing on the Wnt/β-catenin pathway. Methods: Sprague-Dawley rats received a single Aβ 25-35 injection (10μg) into the bilateral hippocampi. DNLA (40 and 80 mg/kg/d) was intragastrically administrated 7d prior to Aβ injection and continued for 28 days. The spatial learning and memory, synaptic morphology, synapse-related proteins, and Wnt signaling components GSK3β and β-catenin phosphorylation were evaluated. Rat primary cortical neuron cultures and AβPP695-PC12 cells were used to evaluate axonal mitochondria distribution, reactive oxygen species production, amyloidogenesis, and Wnt pathway in the protection. Results: DNLA ameliorated Aβ-induced cognitive impairment, increased the number of synapses, elevated the postsynaptic density thickness and expression of synapsin and PSD95 in the hippocampus, and suppressed Aβ-mediated GSK3β activity and the β-catenin phosphorylation. In primary neurons and AβPP695-PC12 cells, DNLA restored Aβ 25-35 induced mitochondrial dysfunction and inhibited reactive oxygen species production and amyloidogenesis. Furthermore, the Wnt/β-catenin pathway inhibitor Dkk-1 blocked the effect of DNLA on the expression of Aβ 1-42 and PSD95. Conclusion: DNLA rescued Aβ-mediated synaptic and mitochondrial injury and inhibited amyloidogenesis in vivo and in vitro, probably through the activation of Wnt/β-catenin signaling pathway to protect synaptic integrity.

Behavioral, neuroplasticity and metabolic effects of 7,8-dihydroxy-4-methylcoumarin associated with physical activity in mice

The search for strategies to develop resilience against metabolic and neuropsychiatric disorders has motivated the clinical and experimental assessment of early life interventions such as lifestyle-based and use of unconventional pharmacological compounds. In this study, we assessed the effects of voluntary physical activity and 7,8-Dihydroxy-4-methylcoumarin (DHMC), independently or in combination, over mice physiological and behavioral parameters, adult hippocampal and hypothalamic neurogenesis, and neurotrophic factors expression in the hypothalamus. C57Bl/6J mice were submitted to a 29-day treatment with DHMC and allowed free access to a running wheel. We found that DHMC treatment alone reduced fasting blood glucose levels. Moreover, physical activity showed an anxiolytic effect in the elevated plus maze task and DHMC produced additional anxiolytic behavior, evidenced by reduced activity during the light cycle in the physical activity group. Although we did not find any differences in hypothalamic or hippocampal adult neurogenesis, DHMC increased gene expression levels of VEGF, which was correlated to the reduced fasting glucose levels. In conclusion, our data emphasize the potential of physical activity in reducing development of neuropsychiatric conditions, such as anxiety, and highlights DHMC as an attractive compound to be investigated in future studies addressing neuropsychiatric disorders associated with metabolic conditions.

Tadalafil and bergapten mitigate streptozotocin-induced sporadic Alzheimer's disease in mice via modulating neuroinflammation, PI3K/Akt, Wnt/β-catenin, AMPK/mTOR signaling pathways

Sporadic Alzheimer's disease (SAD) is a slowly progressive neurodegenerative disorder. This study aimed to investigate neuroprotective potential of tadalafil (TAD) and bergapten (BG) in SAD-induced cognitive impairment in mice. SAD was induced by single injection of streptozotocin (STZ; 3 mg/kg, ICV). STZ resulted in AD-like pathologies including Aβ deposition, tau aggregation, impaired insulin and Wnt/β-catenin signaling, as well as autophagic dysfunction and neuroinflammation. Administration of TAD or BG at doses of 20 and 25 mg/kg, respectively, for 21 consecutive days attenuated STZ-induced hippocampal insult, preserved neuronal integrity, and improved cognitive function in the Morris water maze and object recognition tests paralleled by reduction in Aβ expression by 79 and 89% and tau hyperphosphorylation by 60 and 61%, respectively. TAD and BG also enhanced protein expression of pAkt, pGSK-3β, beclin-1 and methylated protein phosphatase 2A (PP2A) and gene expression of cyclin D1, while raised BDNF immunoreactivity. Furthermore, TAD and BG boosted hippocampal levels of cGMP, PKG, Wnt3a, and AMPK and reduced expression of β-catenin and mTOR by 74% and 51%, respectively. TAD and BG also halted neuroinflammation by reducing IL-23 and IL-27 levels, as well as protein expression of NF-κB by 62% & 61%, respectively. In conclusion, this study offers novel insights on the neuroprotective effects of TAD or BG in the management of SAD as evidenced by improved cognitive function and histological architecture. This could be attributed to modulation of the crosstalk among PI3K/Akt/GSK-3β, PP2A, mTOR/autophagy, cGMP/PKG, and Wnt/β-catenin signaling cascades and mitigation of neuroinflammation.

Regulation of Neurogenesis and Neuronal Differentiation by Natural Compounds

Neuronal damage or degeneration is the main feature of neurological diseases. Regulation of neurogenesis and neuronal differentiation is important in developing therapies to promote neuronal regeneration or synaptic network reconstruction. Neurogenesis is a multistage process in which neurons are generated and integrated into existing neuronal circuits. Neuronal differentiation is extremely complex because it can occur in different cell types and can be caused by a variety of inducers. Recently, natural compounds that induce neurogenesis and neuronal differentiation have attracted extensive attention. In this paper, the potential neural induction effects of medicinal plant-derived natural compounds on neural stem/progenitor cells (NS/PCs), the cultured neuronal cells, and mesenchymal stem cells (MSCs) are reviewed. The natural compounds that are efficacious in inducing neurogenesis and neuronal differentiation include phenolic acids, polyphenols, flavonoids, glucosides, alkaloids, terpenoids, quinones, coumarins, and others. They exert neural induction effects by regulating signal factors and cell-specific genes involved in the process of neurogenesis and neuronal differentiation, including specific proteins (β-tubulin III, MAP-2, tau, nestin, neurofilaments, GFAP, GAP-43, NSE), related genes and proteins (STAT3, Hes1, Mash1, NeuroD1, notch, cyclin D1, SIRT1, reggie-1), transcription factors (CREB, Nkx-2.5, Ngn1), neurotrophins (BDNF, NGF, NT-3) and signaling pathways (JAK/STAT, Wnt/β-catenin, MAPK, PI3K/Akt, GSK-3β/β-catenin, Ca2+/CaMKII/ATF1, Nrf2/HO-1, BMP). The natural compounds with neural induction effects are of great value for neuronal regenerative medicine and provide promising prevention and treatment strategies for neurological diseases.

Osthole: an overview of its sources, biological activities, and modification development

Osthole, also known as osthol, is a coumarin derivative found in several medicinal plants such as Cnidium monnieri and Angelica pubescens. It can be obtained via extraction and separation from plants or total synthesis. Plenty of experiments have suggested that osthole exhibited multiple biological activities covering antitumor, anti-inflammatory, neuroprotective, osteogenic, cardiovascular protective, antimicrobial, and antiparasitic activities. In addition, there has been some research done on the optimization and modification of osthole. This article summarizes the comprehensive information regarding the sources and modification progress of osthole. It also introduces the up-to-date biological activities of osthole, which could be of great value for its use in future research.

Interaction of NF-κB and Wnt/β-catenin Signaling Pathways in Alzheimer's Disease and Potential Active Drug Treatments

The most important neuropathological features of Alzheimer's disease (AD) are extracellular amyloid-β protein (Aβ) deposition, tau protein hyperphosphorylation and activation of neurometabolic reaction in the brain accompanied by neuronal and synaptic damage, and impaired learning and memory function. According to the amyloid cascade hypothesis, increased Aβ deposits in the brain to form the core of the senile plaques that initiate cascade reactions, affecting the synapses and stimulating activation of microglia, resulting in neuroinflammation. A growing number of studies has shown that NF-κB and Wnt/β-catenin pathways play important roles in neurodegenerative diseases, especially AD. In this review, we briefly introduce the connection between neuroinflammation-mediated synaptic dysfunction in AD and elaborated on the mechanism of these two signaling pathways in AD-related pathological changes, as well as their interaction. Based on our interest in natural compounds, we also briefly introduce and conduct preliminary screening of potential therapeutics for AD.

Osthole-Loaded Nanoemulsion Enhances Brain Target in the Treatment of Alzheimer's Disease via Intranasal Administration

Osthole (OST) is a natural coumarin compound that exerts multiple pharmacologic effects. However, the poor water solubility and the low oral absorption of OST limit its clinical application for the treatment of neurologic diseases. A suitable preparation needs to be tailored to evade these unfavourable properties of OST. In this study, an OST nanoemulsion (OST-NE) was fabricated according to the pseudoternary phase diagram method, which was generally used to optimize the prescription in light of the solubility of OST in surfactants and cosurfactants. The final composition of OST-NE was 3.6% of ethyl oleate as oil phase, 11.4% of the surfactant (polyethylene glycol ester of 15-hydroxystearic acid: polyoxyethylene 35 castor oil = 1 : 1), 3% of polyethylene glycol 400 as cosurfactant, and 82% of the aqueous phase. The pharmacokinetic study of OST-NE showed that the brain-targeting coefficient of OST was larger by the nasal route than that by the intravenous route. Moreover, OST-NE inhibited cell death, decreased the apoptosis-related proteins (Bax and caspase-3), and enhanced the activity of antioxidant enzymes (superoxide dismutase and glutathione) in L-glutamate-induced SH-SY5Y cells. OST-NE improved the spatial memory ability, increased the acetylcholine content in the cerebral cortex, and decreased the activity of acetylcholinesterase in the hippocampus of Alzheimer's disease model mice. In conclusion, this study indicates that the bioavailability of OST was improved by using the OST-NE via the nasal route. A low dose of OST-NE maintained the neuroprotective effects of OST, such as inhibiting apoptosis and oxidative stress and regulating the cholinergic system. Therefore, OST-NE can be used as a possible alternative to improve its bioavailability in the prevention and treatment of Alzheimer's disease.

Construction of oxime ester derivatives of osthole from Cnidium monnieri, and evaluation of their agricultural activities and control efficiency

BACKGROUND

In order to discover natural-product-based pesticidal candidates, a series of coumarin-like derivatives containing oxime ester fragments at the C-8 position were prepared by structural modification of osthole, a natural plant product isolated from Cnidium monnieri. Their pesticidal activities were evaluated against two typically fruit trees/crop-threatening agricultural pests, Mythimna separata Walker and Tetranychus cinnabarinus Boisduval.

RESULTS

Osthole was regioselectively oxidized by selenium dioxide to give the E-isomer, (2'E)-3'-formaldehydylosthole (2). Four key steric structures of 2, (2'E, 4'E)-(o-chloropyrid-3-ylcarbonyl)oximinylosthole (4o), (2'E, 4'E)-(styrylcarbonyl)oximinylosthole (4t), and (2'E, 4'E)-(acetyl)oximinylosthole (4w) were undoubtedly confirmed by X-ray crystallography. Against T. cinnabarinus, it is noteworthy that (2'E, 4'E)-(p-chlorophenylcarbonyl)oximinylosthole (4c) exhibited over three-fold more potent acaricidal activity of the precursor osthole, with especially good control efficiency observed in the glasshouse. Against M. separata, compounds 4c and (2'E, 4'E)-(p-nitrophenylcarbonyl)oximinylosthole (4f) showed the most pronounced growth inhibitory activity. The relationships between their structures and agricultural activities also were studied.

CONCLUSION

These results demonstrate that compound 4c could be further structurally modified as pesticidal agents. It will lay the foundation for future application of osthole derivatives as pesticides. © 2020 Society of Chemical Industry.

Shenzao jiannao oral liquid, an herbal formula, ameliorates cognitive impairments by rescuing neuronal death and triggering endogenous neurogenesis in AD-like mice induced by a combination of Aβ42 and scopolamine

ETHNOPHARMACOLOGICAL RELEVANCE

According to the theory of traditional Chinese medicine (TCM), Alzheimer's disease (AD) is identified as "forgetfulness" or "dementia", and is mainly caused by "kidney essence deficiency" which ultimately induces "encephala reduction". Therefore, herbal formulas possessing the efficacy of nourishing kidney essence or replenishing brain marrow are commonly served as effective strategies for AD treatment. Shenzao jiannao oral liquid (SZJN), a traditional Chinese preparation approved by the China Food and Drug Administration (CFDA), is used for the treatment of insomnia and mind fatigue at present for its efficacy of nourishing kidneys. In present study, we found that SZJN could improve cognitive function of AD-like mice.

AIMS OF STUDY

This study aims to investigate the effects of SJZN on ameliorating cognitive deficits of AD-like mouse model, and to illuminate the underlying mechanisms from the perspective of neuroprotection and neurogenesis.

MATERIALS AND METHODS

Kunming mice (28 ± 2 g) were randomly allocated into seven groups: control, sham, model, donepezil and SZJN groups (low, middle and high). The AD mouse model was established by Aβ42 combined with scopolamine. SZJN were intragastrically administrated at doses of 0.3, 1.5 and 7.5 g/kg for 28 days. Morris water maze (MWM) test was applied to determine the cognitive function. Hematoxylin eosin (HE) and Nissl staining were carried out to evaluate pathological damages in the cortex and hippocampal tissues. To explore the protective effects of SZJN on multiple pathogenic factors of AD, protein levels of Aβ42, glial fibrillary acidic protein (GFAP), Bax, Bcl-2, Caspase-3, synaptophysin (SYP), brain-derived neurotrophic factor (BDNF), and neurogenesis related proteins were assessed using Immunofluorescence (IF) and western blot analysis. In vitro, the AD cell model was established by transduction of APP_695swe genes into Neural stem cells (NSCs) isolated from the hippocampal tissues of neonatal C57BL/6 mice. Cell viability assay and neurosphere formation assay were carried out to verify the efficacy of SZJN on proliferation of NSCs.

RESULTS

Our results demonstrated that SZJN (1.5 g/kg and 7.5 g/kg) treatment significantly ameliorated cognitive deficits of AD-like mice. SZJN (7.5 g/kg) treatment significantly retarded the pathological damages including neuronal degeneration, neuronal apoptosis, Aβ peptides aggregation and reaction of astrocytes in AD-like mice. In addition, SZJN (7.5 g/kg) increased the expression of BDNF and SYP, and restored the abnormal level of MDA and SOD in the brain of AD-like mice. Furthermore, SZJN treatment for 28 days remarkably increased the proliferation of NSCs evidenced by more Nestin⁺ and BrdU⁺ cells in the hippocampal DG regions, and increased the amount of mature neurons marked by NeuN both in the cortex and hippocampal DG regions. In vitro, SZJN treatement (16, 32, 64 mg/ml) promoted the proliferation of NSCs evidenced by the increased amount and enlarged size of the neurospheres (p < 0.05).

CONCLUSIONS

Our findings indicated that SZJN could ameliorate cognitive deficits by protecting neurons from death and triggering endogenous neurogenesis. Therefore, SZJN may be considered as a promising agent to restore neuronal loss and deter the deterioration in AD patients.

Molecular Mechanism and Approach in Progression of Meningioma

Meningioma is the most common tumor of the central nervous system, most of which is benign. Even after complete resection, a high rate of recurrence of meningioma is observed. From in-depth study of its pathogenesis, it has been found that a number of chromosomal variations and abnormal molecular signals are closely related to the occurrence and development of malignancy in meningioma, which may provide the theoretical basis and potential direction for accurate and targeted treatment. We have reviewed advances in chromosomal variations and molecular mechanisms involved in the progression of meningioma, and have highlighted the association with malignant biological behavior including cell proliferation, angiogenesis, increased invasiveness, and inhibition of apoptosis. In addition, the chemotherapy of meningioma is summarized and discussed.

Multifunctional osthole liposomes and brain targeting functionality with potential applications in a mouse model of Alzheimer's disease

Osthole (Ost) is a coumarin compound and a potential drug for Alzheimer's disease (AD). However, the effectiveness of Ost is limited by solubility, bioavailability, and low permeability of the blood-brain barrier. In this study, we constructed Ost liposomes with modified CXCR4 on the surface (CXCR4-Ost-Lips), and investigated the intracellular distribution of liposomes in APP-SH-SY5Y cells. In addition, the neuroprotective effect of CXCR4-Ost-Lips was examined in vitro and in vivo. The results showed that CXCR4-Ost-Lips increased intracellular uptake by APP-SH-SY5Y cells and exerted a cytoprotective effect in vitro. The results of Ost brain distribution showed that CXCR4-Ost-Lips prolonged the cycle time of mice and increased the accumulation of Ost in the brain. In addition, CXCR4-Ost-Lips enhanced the effect of Ost in relieving AD-related pathologies. These results indicate that CXCR4-modified liposomes are a potential Ost carrier to treat AD.

Aberrant canonical Wnt signaling: Phytochemical based modulation

BACKGROUND

Wnt signaling pathway plays a major role during development like gastrulation, axis formation, organ development and organization of body plan development. Wnt signaling aberration has been linked with various disease conditions like osteoporosis, colon cancer, hair follicle tumor, Leukemia, and Alzheimer's disease. Phytochemicals like flavonoid, glycosides, polyphenols, have been reported to directly target the markers of Wnt signaling in different disease models.

PURPOSE

The study deals in detail about the different phytochemical targeting key players of Wnt signaling pathway in diseases like Cancer, Osteoporosis, and Alzheimer's disease. We have focused on the Pharmacological basis of disease alleviation by phytochemical specifically targeting the Wnt signaling markers in this study.

METHODS

The study focused on the published articles from the preclinical rodent and invitro cell line studies related to Wnt signaling and Phytochemicals related to Cancer, Alzheimer's and Osteoporosis. The electronic databases Scopus, Web of Science and Pubmed database were used for the systematic search of literatures from 2005 up to 2019 using keywords Canonical Wnt signaling pathway, Cancer, Alzheimer's disease, Osteoporosis, Phytochemicals. The focus was to identify the target specific modulation of Wnt signaling mediated by phytochemicals.

RESULTS

Approximately 30 phytochemicals of different class have been identified to modulate Wnt signaling pathway acting through Axin, β-catenin translocation, GSK-3β, AKT, Wif-1 in various experimental studies. The down regulation of Wnt signaling is observed in Cancer mostly colorectal cancer, breast cancer mediated through mutations in APC and Axin genes. Different class of Phytochemicals such as flavonoid, glycosides, polyphenol, alkaloids etc. have been found to target Wnt signaling markers and alleviate Cancer. Similarly, Up regulation of Wnt signaling has been reported in Osteoporosis and neurodegenerative disease like Alzheimer's disease.

CONCLUSION

This review highlights the possibility of the Phytochemicals to target Wnt markers and its potential to either activate or deactivate the Wnt signaling pathway. It also describes the challenges in proper targeting of Wnt signaling and the potential risk and consequences of either up regulation or down regulation of the signaling pathway. This article highlights the possibility of Wnt signaling pathway as a therapeutic option in different diseases.

Osthole ameliorates cognitive impairments via augmenting neuronal population in APP / PS1 transgenic mice

Alzheimer's disease (AD) is a neurodegenerative disorder with notable factors of dysfunction in multiple neurological changes, encompassing neuronal loss in the frontal cortex and hippocampal regions. Dysfunction of proliferation and self-renewal of neural stem cells (NSCs) was observed in AD patients and animals. Thereby, mobilizing endogenous neurogenesis by pharmacological agents would provide a promising route for neurodegeneration. Osthole (Ost), a natural coumarin derivative, has been reported to exert extensive neuroprotective effects in AD. However, whether ost can facilitate endogenous neurogenesis against AD in vivo is still unknown. In this study, by using Morris water maze (MWM) test, hematoxylin-eosin (HE) staining, Nissl staining, immunofluorescence analysis and western blot, we demonstrated that oral administration of ost could improve the learning and memory function, inhibit neuronal apoptosis, elevate the expression of glial cell line derived neurotrophic factor (GDNF), synaptophysin (SYP) and postsynaptic density protein 95 (PSD95). Moreover, ost could remarkably enhance proliferation of NSCs and increase the amount of mature neurons in APP/PS1 transgenic mice. Together, our findings demonstrated that ost possessed the ability of promoting endogenous neurogenesis and ost could be served as a plausible agent to reverse or slow down the progress of AD.

Thalidomide Inhibits Human iPSC Mesendoderm Differentiation by Modulating CRBN-dependent Degradation of SALL4

Exposure to thalidomide during a critical window of development results in limb defects in humans and non-human primates while mice and rats are refractory to these effects. Thalidomide-induced teratogenicity is dependent on its binding to cereblon (CRBN), the substrate receptor of the Cul4A-DDB1-CRBN-RBX1 E3 ubiquitin ligase complex. Thalidomide binding to CRBN elicits subsequent ubiquitination and proteasomal degradation of CRBN neosubstrates including SALL4, a transcription factor of which polymorphisms phenocopy thalidomide-induced limb defects in humans. Herein, thalidomide-induced degradation of SALL4 was examined in human induced pluripotent stem cells (hiPSCs) that were differentiated either to lateral plate mesoderm (LPM)-like cells, the developmental ontology of the limb bud, or definitive endoderm. Thalidomide and its immunomodulatory drug (IMiD) analogs, lenalidomide, and pomalidomide, dose-dependently inhibited hiPSC mesendoderm differentiation. Thalidomide- and IMiD-induced SALL4 degradation can be abrogated by CRBN V388I mutation or SALL4 G416A mutation in hiPSCs. Genetically modified hiPSCs expressing CRBN E377V/V388I mutant or SALL4 G416A mutant were insensitive to the inhibitory effects of thalidomide, lenalidomide, and pomalidomide on LPM differentiation while retaining sensitivity to another known limb teratogen, all-trans retinoic acid (atRA). Finally, disruption of LPM differentiation by atRA or thalidomide perturbed subsequent chondrogenic differentiation in vitro. The data here show that thalidomide, lenalidomide, and pomalidomide affect stem cell mesendoderm differentiation through CRBN-mediated degradation of SALL4 and highlight the utility of the LPM differentiation model for studying the teratogenicity of new CRBN modulating agents.

Phytochemistry, Ethnopharmacology, Pharmacokinetics and Toxicology of Cnidium monnieri (L.) Cusson

Cnidium monnieri (L.) Cusson (CMC) is a traditional Chinese herbal medicine that has been widely grown and used in Asia. It is also known as "She chuang zi" in China (Chinese: ), "Jashoshi" in Japan, "Sasangia" in Korea, and "Xa sang tu" in Vietnam. This study aimed to provide an up-to-date review of its phytochemistry, ethnopharmacology, pharmacokinetics, and toxicology. All available information on CMC was collected from the Encyclopedia of Traditional Chinese Medicines, PubMed, EMBASE, ScienceDirect, Scopus, Web of Science, and China Network Knowledge Infrastructure. The updated chemical structures of the compounds are those ones without chemical ID numbers or references from the previous review. A total of 429 chemical constituents have been elucidated and 56 chemical structures have been firstly identified in CMC with traceable evidence. They can be categorized as coumarins, volatile constituents, liposoluble compounds, chromones, monoterpenoid glucosides, terpenoids, glycosides, glucides, and other compounds. CMC has demonstrated impressive potential for the management of various diseases in extensive preclinical research. Since most of the studies are overly concentrated on osthole, more research is needed to investigate other chemical constituents.

Precision Medicine in Neurodegenerative Diseases: Some Promising Tips Coming from the microRNAs' World

: Novel insights in the development of a precision medicine approach for treating the neurodegenerative diseases (NDDs) are provided by emerging advances in the field of pharmacoepigenomics. In this context, microRNAs (miRNAs) have been extensively studied because of their implication in several disorders related to the central nervous system, as well as for their potential role as biomarkers of diagnosis, prognosis, and response to treatment. Recent studies in the field of neurodegeneration reported evidence that drug response and efficacy can be modulated by miRNA-mediated mechanisms. In fact, miRNAs seem to regulate the expression of pharmacology target genes, while approved (conventional and non-conventional) therapies can restore altered miRNAs observed in NDDs. The knowledge of miRNA pharmacoepigenomics may offers new clues to develop more effective treatments by providing novel insights into interindividual variability in drug disposition and response. Recently, the therapeutic potential of miRNAs is gaining increasing attention, and miRNA-based drugs (for cancer) have been under observation in clinical trials. However, the effective use of miRNAs as therapeutic target still needs to be investigated. Here, we report a brief review of representative studies in which miRNAs related to therapeutic effects have been investigated in NDDs, providing exciting potential prospects of miRNAs in pharmacoepigenomics and translational medicine.

Synergistic effects of Pb and repeated heat pulse on developmental neurotoxicity in zebrafish

Pollutant discharges to the aquatic environment often contain multiple environmental stressors, affecting aquatic organisms. To mimic the discharges from nuclear and industry facilities, the combined effects of two independent types of stressors, heavy metal Pb and repeated heat pulse were addressed in this study. We investigated the developmental toxicity of combined treatment, especially its toxic effects on zebrafish neurodevelopment. The normal embryos at 4 hpf were exposed to 0.2 mM of Pb dissolved in the bathing medium with different temperatures (30, 32, and 34 °C) and then maintained in an incubator at 28 °C. After performing above treatment once every 24 h for 6 days, we found that combined treatment significantly affected neural development, including loss of dopaminergic (DA) neurons and brain vasculature, disruption of locomotor activity and neurodevelopmental genes expression in a temperature-dependent manner as compared to the Pb alone exposure group, indicating that repeated heat pulse enhances these negative impacts induced by Pb. In contrast, no apparent toxicity was observed in repeated heat pulse alone groups, suggesting that Pb treatment reduces thermal tolerance in zebrafish, which emphasized the importance to evaluate synergistic effects of Pb and repeated heat pulse. Moreover, repeated heat pulse aggravated Pb-induced apoptosis in the zebrafish brain. Further study of the underlying mechanism suggested that Caspase 3 regulated apoptosis was involved in this process. Taken together, our findings shed light on the full understanding of toxic effects of discharges from industrial applications on living organisms and its environmental impact.

Osthole alleviates inflammation by down-regulating NF-κB signaling pathway in traumatic brain injury

Traumatic brain injury (TBI) is a common neurotrosis disorder of the central nervous system (CNS), which has dramatic consequences on the integrity of damaged tissue. In this study, we investigated the neuroprotective effect and anti-inflammatory actions of osthole, a natural coumarin derivative, in both in vivo and in vitro TBI models. We first prepared a mouse model of cortical stab wound brain injury, investigated the capacity for osthole to prevent secondary brain injury and further examined the underlying mechanism. We revealed that osthole significantly improved the neurological function, increased the number of neurons beside injured site. Additionally, osthole treatment reduced the expression of microglia and glial scar, lowered the level of the proinflammatory cytokines interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α), and blocked the activation of nuclear factor kappa B (NF-κB). Furthermore, the protective effect of osthole was also examined in SH-SY5Y cells subjected to scratch injury. Treatment of osthole prominently suppressed cell apoptosis and inflammatory factors release by blocking injury-induced IκB-α phosphorylation and NF-κB translocation, and upregulated the IκB-α which functions in the NF-κB signaling pathway of SH-SY5Y cells. However, NF-κB signaling pathway was inhibited by pyrrolidine dithiocarbamate (PDTC), an NF-κB inhibitor, the anti-inflammatory effect of osthole was abolished. In conclusion, our findings demonstrated that osthole attenuated inflammatory response by inhibiting the NF-κB pathway in TBI.

Glutamine Improves Oxidative Stress through the Wnt3a/β-Catenin Signaling Pathway in Alzheimer's Disease In Vitro and In Vivo

Background/Aims

Alzheimer's disease (AD) is the most common neurodegenerative disease, and all researchers working in this field agree that oxidative stress is intimately associated with Alzheimer disease. In this study, we hypothesized that glutamine (Gln) offers protection against oxidative stress injury in SAMP8 mice as well as the underlying mechanism.

Methods

The SAMP8 mice received glutamine intragastrically for 8 consecutive weeks to evaluate the protective effect of glutamine on oxidative stress in AD mice involving Wnt3a/β-catenin signaling pathway. In addition, rat pheochromocytoma tumor cell line PC12 was pretreated with 32 μM glutamine for 2 h followed by 24 h incubation with 40 μM Aβ25-35 to obtain in vitro data.

Results

In vivo the administration of glutamine was found to ameliorate behavioral deficits and neuron damage, increase superoxide dismutase (SOD) and glutathione peroxidase (GSH-XP) activity, reduce the malondialdehyde (MDA) content, and activate the Wnt3a/β-catenin signaling pathway in SAMP8 mice. In vitro glutamine treatment decreased the toxicity of Aβ25-35 on PC12 cells and prevented apoptosis. Additionally, glutamine treatment increased SOD and GSH-XP activity and decreased MDA content and increased Wnt3a and β-catenin protein levels. Interestingly, the DKK-1 (Wnt3a/β-catenin pathway inhibitor) decreased the antioxidant capacity of glutamine in Aβ25-35-treated PC12 cells.

Conclusion

This study suggests that glutamine could protect against oxidative stress-induced injury in AD mice via the Wnt3a/β-catenin signaling pathway.

Osthole attenuates APP-induced Alzheimer's disease through up-regulating miRNA-101a-3p

AIM

Alzheimer's disease (AD) is a slowly progressing neurodegenerative disorder that attributed to the increase of amyloid precursor protein (APP). Recently, evidence indicates that microRNA alterations are involved in the development of AD. In this paper, we demonstrated whether osthole could delay the occurrence of AD by regulating miRNA.

METHODS

Microarray was used to discover differential miRNAs in AD. The target genes regulated by miRNA were predicted by databases; The protective effects of osthole on APP/PS1 mice were determined by Morris Water Maze, H&E and Nissl staining; The APP-SH-SY5Y cells were transfected with miRNA-101a-3p inhibitor, the expression of miRNA-101a-3p and APP mRNA in APP/PS1 mice and APP-SH-SY5Y cells were detected by RT-PCR; And western blot and ICC staining were used to detect the APP and Aβ proteins expression.

KEY FINDINGS

MiRNA-101a-3p was the osthole-mediated miRNA in AD and APP is the target gene. Osthole could increase the learning and memory ability in APP/PS1 mice and inhibit APP mRNA/protein expression by up-regulating miRNA-101a-3p. For exploring the underlying mechanism, miR-101a-3p inhibitor was transfected into the APP-SH-SY5Y cells. We can know that osthole had a protective effect on APP-SH-SY5Y cells, and it could raise miRNA-101a-3p expression and inhibit APP mRNA/protein expression, the formation of Aβ protein was inhibited too.

SIGNIFICANCE

These results emphasized that osthole had a protective effect on APP/PS1 mice and APP-SH-SY5Y cells. The main cause was due to osthole could inhibit APP expression by up-regulating miRNA-101a-3p so as to help delay the occurrence of AD.

Osthole alleviates MPTP-induced Parkinson's disease mice by suppressing Notch signaling pathway

Objectives: Parkinson's disease (PD) is an age-related neurodegenerative disease characterized by motor dysfunctions. Dopaminergic neuron loss, inflammation and oxidative stress responses play key roles in the pathogenisis of PD. Osthole (Ost), a natural coumarin derivative, isolated from various herbs such as Cnidium monnieri (L.), has anti-inflammatory, anti-apoptotic and anti-oxidative stress properties. However, whether it has effects on PD is unknown. Methods: In this study, mice were subjected to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injection to induce PD symptoms, and treated with osthole. Stepping and cylinder tests were performed to determine their motor function. Immunohistochemical and immunofluorescence staining were performed to detect tyrosine hydroxylase (TH) and ionized calcium binding adaptor molecule 1 (Iba-1). The expression levels of inflammatory cytokines and oxidative stress factors were detected by qPCR and ELISA. Notch signaling pathway was investigated by western blot. Results: We found that injection of MPTP induced motor deficits in mice, enhanced the loss dopaminergic neurons and the activation of microglia, increased inflammatory and oxidative stress responses, and inhibited Notch signaling pathway. Osthole treatment suppressed theses MPTP-induced alterations. Conclusion: In conclusion, osthole attenuates PD symptoms by suppressing Notch signaling pathway.

RETRACTED: Osthole decreases tau protein phosphorylation via PI3K/AKT/GSK-3β signaling pathway in Alzheimer's disease

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of Editor-in-Chief. The corresponding author notified the journal of image duplications within the published article and requested a corrigendum. Specifically, the ‘APP/PS1’ plot in Figure 1A had appeared in a previous publication [Panaxadiol inhibits synaptic dysfunction in Alzheimer's disease and targets the Fyn protein in APP/PS1 mice and APP-SH-SY5Y cells, Life Sciences (DOI: 10.1016/j.lfs.2019.03.070)], as the ‘TG’ plot in Figure 2A. In addition, several image duplications were identified within the panels of Figure 2. These issues, and others relating to unusual characteristics within the western blots, have been detailed here: https://pubpeer.com/publications/892AF7E4913255548C1446247FC65A#. As per journal policy when considering corrigendum requests, the journal requested the authors to provide explanations and source data relating to these affected figures. Upon receipt of additional source data, the editorial team noticed additional suspected image duplications. In relation to Figure 1A, the corresponding author stated that “…we mistakenly used the same Morris Water Maze data”, and a corrected figure was submitted. In relation to the image duplications within Figure 2, the corresponding author stated “…we mistakenly used the copy-and-paste tool instead of a color adjustment tool” during image post-processing. The corresponding author was unable to produce original unaltered and uncropped western blot source data. The editorial team have concerns about the provenance of the data and therefore the Editor-in-Chief decided to retract the article.

Silencing of Long Noncoding RNA SOX21-AS1 Relieves Neuronal Oxidative Stress Injury in Mice with Alzheimer's Disease by Upregulating FZD3/5 via the Wnt Signaling Pathway

Alzheimer's disease (AD) represents a progressive neurodegenerative disorder characterized by distinctive neuropathological changes. Recently, long noncoding RNAs (lncRNAs) have become a key area of interest due to their potential in AD therapy. Hence, the aim of the current study was to investigate the effect of lncRNA SOX21-AS1 on neuronal oxidative stress injury in mice with AD via the Wnt signaling pathway by targeting FZD3/5. Microarray analysis was performed to screen AD-related differentially expressed genes (DEGs). Following verification of the target relationship between SOX21-AS1 and FZD3/5, the contents of OH^-, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were determined, with the expressions of SOX21-AS1, FZD3/5, β-catenin, cyclin D1, and 4-HNE in hippocampal neuron cells subsequently detected. Cell cycle distribution and apoptosis were evaluated. Bioinformatics analysis revealed that SOX21-AS1 was upregulated in AD, while highlighting the co-expression of SOX21-AS1 and FZD3/5 genes and their involvement in the Wnt signaling pathway. AD mice exhibited diminished memory and learning ability, increased rates of MDA, OH^-, SOX21-AS1, 4-HNE, and elevated levels of hippocampal neuron cell apoptosis, accompanied by decreased levels of SOD, CAT, GSH-Px, FZD3/5, β-catenin, and cyclin D1. Silencing of SOX21-AS1 resulted in decreased OH^-, MDA contents, SOX21-AS1, and 4-HNE, and increased SOD, CAT, GSH-Px, FZD3/5, β-catenin, and cyclin D1, as well as reduced apoptosis of hippocampal neuron cells. Taken together, the key findings of the present study demonstrated that silencing of lncRNA SOX21-AS1 could act to alleviate neuronal oxidative stress and suppress neuronal apoptosis in AD mice through the upregulation of FZD3/5 and subsequent activation of the Wnt signaling pathway.

Osthole Delays Tert-Butyl Hydroperoxide-Induced Premature Senescence in Neural Stem Cells

In our previous study, we found that osthole could promote the ability of proliferation and differentiation in normal neural stem cells (NSCs) under normal condition. Then, we used tert-butyl hydroperoxide (t-BHP) to establish the model of senescence NSCs to detect the effects of osthole. Interestingly, the immunofluorescence results showed that osthole (100 μM) could enhance the ability of proliferation and differentiation, and CCK-8 assay results showed that osthole could also enhance the cell viabilities. Then, SA-β-gal assay results showed that osthole could decrease the positive of senescence cells. Flow cytometric analysis results showed that osthole could decrease the mixture of G0 and G1 phase. Reverse transcriptase (RT)-polymerase chain reaction results showed that osthole could downregulate the expression of p16 mRNA, and western blot analysis results showed that the expressions of the target protein decreased in p16-pRb signaling pathway with osthole treatment. In conclusion, these results indicated that osthole could probably delay cells senescence through p16-pRb signaling pathway.

Fluoxetine attenuates the impairment of spatial learning ability and prevents neuron loss in middle-aged APPswe/PSEN1dE9 double transgenic Alzheimer's disease mice

Selective serotonin reuptake inhibitors (SSRIs) have been reported to increase cognitive performance in some clinical studies of Alzheimer's disease (AD). However, there is a lack of evidence supporting the efficacy of SSRIs as cognition enhancers in AD, and the role of SSRIs as a treatment for AD remains largely unclear. Here, we characterized the impact of fluoxetine (FLX), a well-known SSRI, on neurons in the dentate gyrus (DG) and in CA1 and CA3 of the hippocampus of middle-aged (16 to 17 months old) APPswe/PSEN1dE9 (APP/PS1) transgenic AD model mice. We found that intraperitoneal (i.p.) injection of FLX (10 mg/kg/day) for 5 weeks effectively alleviated the impairment of spatial learning ability in middle-aged APP/PS1 mice as evaluated using the Morris water maze. More importantly, the number of neurons in the hippocampal DG was significantly increased by FLX. Additionally, FLX reduced the deposition of beta amyloid, inhibited GSK-3β activity and increased the level of β-catenin in middle-aged APP/PS1 mice. Collectively, the results of this study indicate that FLX delayed the progression of neuronal loss in the hippocampal DG in middle-aged AD mice, and this effect may underlie the FLX-induced improvement in learning ability. FLX may therefore serve as a promising therapeutic drug for AD.

Osthole promotes endogenous neural stem cell proliferation and improved neurological function through Notch signaling pathway in mice acute mechanical brain injury

Mechanical brain injury (MBI) is a common neurotrosis disorder of the central nervous system (CNS), which has a higher mortality and disability. In the case of MBI, neurons death leads to loss of nerve function. To date, there was no satisfactory way to restore neural deficits caused by MBI. Endogenous neural stem cells (NSCs) can proliferate, differentiate and migrate to the lesions after brain injury, to replace and repair the damaged neural cells in the subventricular zone (SVZ), hippocampus and the regions of brain injury. In the present study, we first prepared a mouse model of cortical stab wound brain injury. Using the immunohistochemical and hematoxylin-eosin (H&E) staining method, we demonstrated that osthole (Ost), a natural coumarin derivative, was capable of promoting the proliferation of endogenous NSCs and improving neuronal restoration. Then, using the Morris water maze (MWM) test, we revealed that Ost significantly improved the learning and memory function in the MBI mice, increased the number of neurons in the regions of brain injury, hippocampus DG and CA3 regions. Additionally, we found that Ost up-regulated the expression of self-renewal genes Notch 1 and Hes 1. However, when Notch activity was blocked by the γ-secretase inhibitor DAPT, the expression of Notch 1 and Hes 1 mRNA was down-regulated, augmentation of NICD and Hes 1 protein was ameliorated, the proliferation-inducing effect of Ost was abolished. These results suggested that the effects of Ost were at least in part mediated by activation of Notch signaling pathway. Our findings support that Ost is a potential drug for treating MBI due to its neuronal restoration.

Osthole Stimulated Neural Stem Cells Differentiation into Neurons in an Alzheimer's Disease Cell Model via Upregulation of MicroRNA-9 and Rescued the Functional Impairment of Hippocampal Neurons in APP/PS1 Transgenic Mice

Alzheimer's disease (AD) is the most serious neurodegenerative disease worldwide and is characterized by progressive cognitive impairment and multiple neurological changes, including neuronal loss in the brain. However, there are no available drugs to delay or cure this disease. Consequently, neuronal replacement therapy may be a strategy to treat AD. Osthole (Ost), a natural coumarin derivative, crosses the blood-brain barrier and exerts strong neuroprotective effects against AD in vitro and in vivo. Recently, microRNAs (miRNAs) have demonstrated a crucial role in pathological processes of AD, implying that targeting miRNAs could be a therapeutic approach to AD. In the present study, we investigated whether Ost could enhance cell viability and prevent cell death in amyloid precursor protein (APP)-expressing neural stem cells (NSCs) as well as promote APP-expressing NSCs differentiation into more neurons by upregulating microRNA (miR)-9 and inhibiting the Notch signaling pathway in vitro. In addition, Ost treatment in APP/PS1 double transgenic (Tg) mice markedly restored cognitive functions, reduced Aβ plague production and rescued functional impairment of hippocampal neurons. The results of the present study provides evidence of the neurogenesis effects and neurobiological mechanisms of Ost against AD, suggesting that Ost is a promising drug for treatment of AD or other neurodegenerative diseases.

Differential Impacts of Alternative Splicing Networks on Apoptosis

Apoptosis functions as a common mechanism to eliminate unnecessary or damaged cells during cell renewal and tissue development in multicellular organisms. More than 200 proteins constitute complex networks involved in apoptotic regulation. Imbalanced expressions of apoptosis-related factors frequently lead to malignant diseases. The biological functions of several apoptotic factors are manipulated through alternative splicing mechanisms which expand gene diversity by generating discrete variants from one messenger RNA precursor. It is widely observed that alternatively-spliced variants encoded from apoptosis-related genes exhibit differential effects on apoptotic regulation. Alternative splicing events are meticulously regulated by the interplay between trans-splicing factors and cis-responsive elements surrounding the regulated exons. The major focus of this review is to highlight recent studies that illustrate the influences of alternative splicing networks on apoptotic regulation which participates in diverse cellular processes and diseases.

Neurotrophin-3 promotes proliferation and cholinergic neuronal differentiation of bone marrow- derived neural stem cells via notch signaling pathway

AIMS

Recently, the potential for neural stem cells (NSCs) to be used in the treatment of Alzheimer's disease (AD) has been reported; however, the therapeutic effects are modest by virtue of the low neural differentiation rate. In our study, we transfected bone marrow-derived NSCs (BM-NSCs) with Neurotrophin-3 (NT-3), a superactive neurotrophic factor that promotes neuronal survival, differentiation, and migration of neuronal cells, to investigate the effects of NT-3 gene overexpression on the proliferation and differentiation into cholinergic neuron of BM-NSCs in vitro and its possible molecular mechanism.

MAIN METHODS

BM-NSCs were generated from BM mesenchymal cells of adult C57BL/6 mice and cultured in vitro. After transfected with NT-3 gene, immunofluorescence and RT-PCR method were used to determine the ability of BM-NSCs on proliferation and differentiation into cholinergic neuron; Acetylcholine Assay Kit was used for acetylcholine (Ach). RT-PCR and WB analysis were used to characterize mRNA and protein level related to the Notch signaling pathway.

KEY FINDINGS

We found that NT-3 can promote the proliferation and differentiation of BM-NSCs into cholinergic neurons and elevate the levels of acetylcholine (ACh) in the supernatant. Furthermore, NT-3 gene overexpression increase the expression of Hes1, decreased the expression of Mash1 and Ngn1 during proliferation of BM-NSCs. Whereas, the expression of Hes1 was down-regulated, and Mash1 and Ngn1 expression were up-regulated during differentiation of BM-NSCs.

SIGNIFICANCE

Our findings support the prospect of using NT-3-transduced BM-NSCs in developing therapies for AD due to their equivalent therapeutic potential as subventricular zone-derived NSCs (SVZ-NSCs), greater accessibility, and autogenous attributes.

How Wnt Signaling Builds the Brain: Bridging Development and Disease

Wnt/β-catenin signaling plays a crucial role throughout all stages of brain development and remains important in the adult brain. Accordingly, many neurological disorders have been linked to Wnt signaling. Defects in Wnt signaling during neural development can give rise to birth defects or lead to neurological dysfunction later in life. Developmental signaling events can also be hijacked in the adult and result in disease. Moreover, knowledge about the physiological role of Wnt signaling in the brain might lead to new therapeutic strategies for neurological diseases. Especially, the important role for Wnt signaling in neural differentiation of pluripotent stem cells has received much attention as this might provide a cure for neurodegenerative disorders. In this review, we summarize the versatile role of Wnt/β-catenin signaling during neural development and discuss some recent studies linking Wnt signaling to neurological disorders.

Neuroprotective Effect of Osthole on Neuron Synapses in an Alzheimer's Disease Cell Model via Upregulation of MicroRNA-9

Accumulation of β-amyloid peptide (Aβ) in the brain plays an important role in the pathogenesis of Alzheimer's disease (AD). It has been reported that osthole exerts its neuroprotective effect on neuronal synapses, but its exact mechanism is obscure. Recently, microRNAs have been demonstrated to play a crucial role in inducing synaptotoxicity by Aβ, implying that targeting microRNAs could be a therapeutic approach of AD. In the present study, we investigated the neuroprotective effects of osthole on a cell model of AD by transducing APP695 Swedish mutant (APP695swe, APP) into mouse cortical neurons and human SH-SY5Y cells. In this study, the cell counting kit CCK-8, apoptosis assay, immunofluorescence analysis, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction, and Western blot assay were used. We found that osthole could enhance cell viability, prevent cell death, and reverse the reduction of synaptic proteins (synapsin-1, synaptophysin, and postsynaptic density-95) in APP-overexpressed cells, which was attributed to increases in microRNA-9 (miR-9) expression and subsequent decreases in CAMKK2 and p-AMPKα expressions. These results demonstrated that osthole plays a neuroprotective activity role in part through upregulating miR-9 in AD.