Schisandrin ameliorates cognitive impairment and attenuates Aβ deposition in APP/PS1 transgenic mice: involvement of adjusting neurotransmitters and their metabolite changes in the brain

Di-caffeoylquinic acid: a potential inhibitor for amyloid-beta aggregation

Alzheimer's disease (AD) remains a challenging neurodegenerative disorder with limited therapeutic success. Traditional Chinese Medicine (TCM), as a promising new source for AD, still requires further exploration to understand its complex components and mechanisms. Here, focused on addressing Aβ (1-40) aggregation, a hallmark of AD pathology, we employed a Thioflavin T fluorescence labeling method for screening the active molecular library of TCM which we established. Among the eight identified, 1,3-di-caffeoylquinic acid emerged as the most promising, exhibiting a robust binding affinity with a KD value of 26.7 nM. This study delves into the molecular intricacies by utilizing advanced techniques, including two-dimensional (2D) 15N-1H heteronuclear single quantum coherence nuclear magnetic resonance (NMR) and molecular docking simulations. These analyses revealed that 1,3-di-caffeoylquinic acid disrupts Aβ (1-40) self-aggregation by interacting with specific phenolic hydroxyl and amino acid residues, particularly at Met-35 in Aβ (1-40). Furthermore, at the cellular level, the identified compounds, especially 1,3-di-caffeoylquinic acid, demonstrated low toxicity and exhibited therapeutic potential by regulating mitochondrial membrane potential, reducing cell apoptosis, and mitigating Aβ (1-40)-induced cellular damage. This study presents a targeted exploration of catechol compounds with implications for effective interventions in AD and sheds light on the intricate molecular mechanisms underlying Aβ (1-40) aggregation disruption.

Human-Derived Induced GABAergic Progenitor Cells Improve Cognitive Function in Mice and Inhibit Astrocyte Activation with Anti-Inflammatory Exosomes

OBJECTIVE

The role of gamma-aminobutyric acid-ergic (GABAergic) neuron impairment in Alzheimer's disease (AD), and if and how transplantation of healthy GABAergic neurons can improve AD, remain unknown.

METHODS

Human-derived medial ganglionic eminence progenitors (hiMGEs) differentiated from programmed induced neural precursor cells (hiNPCs) were injected into the dentate gyrus region of the hippocampus (HIP).

RESULTS

We showed that grafts migrate to the whole brain and form functional synaptic connections in amyloid precursor protein gene/ presenilin-1 (APP/PS1) chimeric mice. Following transplantation of hiMGEs, behavioral deficits and AD-related pathology were alleviated and defective neurons were repaired. Notably, exosomes secreted from hiMGEs, which are rich in anti-inflammatory miRNA, inhibited astrocyte activation in vitro and in vivo, and the mechanism was related to regulation of CD4+ Th1 cells mediated tumor necrosis factor (TNF) pathway.

INTERPRETATION

Taken together, these findings support the hypothesis that hiMGEs transplantation is an alternative treatment for neuronal loss in AD and demonstrate that exosomes with anti-inflammatory activity derived from hiMGEs are important factors for graft survival. ANN NEUROL 2024.

Schisandrol A, the Major Active Constitute in Schisandra chinensis: A Review of Its Preparation, Biological Activities, and Pharmacokinetics Analysis

Schisandra chinensis (S. chinensis) has a long history as a traditional Chinese medicine that is astringent, beneficial to vital energy, tonifies the kidney, tranquilizes the heart, etc. Significantly, Schisandrol A (SA) is extracted from S. chinensis and shows surprising and satisfactory biological activity, including anti-inflammatory, hepatoprotective, cardiovascular protection, and antitumor properties, among others. SA has a more pronounced protective effect on central damaged nerves among its numerous pharmacological effects, improving neurodegenerative diseases such as Alzheimer's and Parkinson's through the protection of damaged nerve cells and the enhancement of anti-oxidant capacity. Pharmacokinetic studies have shown that SA has a pharmacokinetic profile with a rapid absorption, wide distribution, maximal concentration in the liver, and primarily renal excretion. However, hepatic and intestinal first-pass metabolism can affect SA's bioavailability. In addition, the content of SA, as an index component of S. chinensis Pharmacopoeia, should not be less than 0.40%, and the content of SA in S. chinensis compound formula was determined with the help of high-performance liquid chromatography (HPLC), which is a stable and reliable method, and it can lay a foundation for the subsequent quality control. Therefore, this paper systematically reviews the preparation, pharmacological effects, pharmacokinetic properties, and content determination of SA with the goal of updating and deepening the understanding of SA, as well as providing a theoretical basis for the study of SA at a later stage.

Gut microbiome-based therapies for alleviating cognitive impairment: state of the field, limitations, and future perspectives

Cognitive impairment (CI) is a multifaceted neurological condition that can trigger negative emotions and a range of concurrent symptoms, imposing significant public health and economic burdens on society. Therefore, it is imperative to discover a remedy for CI. Nevertheless, the mechanisms behind the onset of this disease are multifactorial, which makes the search for effective amelioration difficult and complex, hindering the search for effective measures. Intriguingly, preclinical research indicates that gut microbiota by influencing brain function, plays an important role in the progression of CI. Furthermore, numerous preclinical studies have highlighted the potential of probiotics, prebiotics, fecal microbiota transplantation (FMT), and diet in modulating the gut microbiota, thereby ameliorating CI symptoms. This review provides a comprehensive evaluation of CI pathogenesis, emphasizing the contribution of gut microbiota disorders to CI development. It also summarizes and discusses current strategies and mechanisms centered on the synergistic role of gut microbiota modulation in the microbiota-gut-brain axis in CI development. Finally, problems with existing approaches are contemplated and the development of microbial modulation strategies as therapeutic approaches to promote and restore brain cognition is discussed. Further research considerations and directions are highlighted to provide ideas for future CI prevention and treatment strategies.

A comprehensive review on Schisandrin and its pharmacological features

Schisandrin stands as one of the primary active compounds within the widely used traditional medicinal plant Schisandra chinensis (Turcz.) Baill. This compound exhibits sedative, hypnotic, anti-aging, antioxidant, and immunomodulatory properties, showcasing its effectiveness across various liver diseases while maintaining a favorable safety profile. However, the bioavailability of schisandrin is largely affected by hepatic and intestinal first-pass metabolism, which limits the clinical efficacy of schisandrin. In this paper, we review the various pharmacological effects and related mechanisms of schisandrin, in order to provide reference for subsequent drug research and promote its medicinal value.

Identification of histone acetylation modification sites in the striatum of subchronically manganese-exposed rats

Aim: To explore the specific histone acetylation sites and oxidative stress-related genes that are associated with the pathogenesis of manganese toxicity. Methods: We employed liquid chromatography-tandem mass spectrometry and bioinformatics analysis to identify acetylated proteins in the striatum of subchronic manganese-intoxicated rats. Results: We identified a total of 12 differentially modified histone acetylation sites: H3K9ac, H3K14ac, H3K18ac, H3K56ac and H3K79ac were upregulated and H3K27ac, H3K36ac, H4K91ac, H4K79ac, H4K31ac, H2BK16ac and H2BK20ac were downregulated. Additionally, we found that CAT, SOD1 and SOD2 might be epigenetically regulated and involved in the pathogenesis of manganism. Conclusion: This study identified histone acetylation sites and oxidative stress-related genes associated with the pathogenesis of manganese toxicity, and these findings are useful in the search for potential epigenetic targets for manganese toxicity.

Combination of Alpinia Oxyphylla Fructus and Schisandra Chinensis Fructus ameliorates aluminum-induced Alzheimer's disease via reducing BACE1 expression

Being the most common form of dementia, Alzheimer's disease (AD) has a series of modifiable risk factors, including metal ions represented by aluminium. Aluminium (Al) exhibits its neurotoxic effects, especially mainly by affecting amyloid-β protein (Aβ) aggregation and Tau hyperphosphorylation. As reported in our previous study, the combination of Alpinia Oxyphylla Fructus and Schisandra Chinensis Fructus (AS) had a neuroprotective effect. This study aimed to evaluate the anti-AD effect of AS and the mechanism by which AS reduces the neurotoxic effect of Al. Firstly, we used aluminium-maltol (Al(mal)₃) to construct a mouse model of AD and performed oral administration of AS, followed by behavioral experiments, and we collected the mouse brain for immunohistochemistry analysis. In vivo results showed that AS significantly improved Al-induced cognitive decline in mice, and reduced the levels of Aβ_1-42 and P-Tau in the brain, which further proved the anti-AD effect of AS. Then, in order to explore the mechanism by which AS reduced Aβ_1-42, Al-induced PC12 cells were used for the in vitro experiments. Compared with other ratios, the ratio of Alpinia Oxyphylla Fructus: Schisandra Chinensis Fructus (AO:SC) = 1:2 could better improve the cell viability and reduce the Aβ_1-42 level. According to western blot and quantitative real-time polymerase chain reaction (qPCR) results, AS ameliorated the pathological process by downregulating the expression of β-secretase (BACE1), rather than by reducing the expression of amyloid precursor protein (APP) or Tau. These results suggest that AS ameliorated Al-induced AD by affecting the expression of BACE1 and reducing the level of Aβ_1-42, thereby exerting a neuroprotective effect. Combined with previous studies, this study shows that AS has potential for further research and development in AD treatment.

Bazi Bushen capsule attenuates cognitive deficits by inhibiting microglia activation and cellular senescence

CONTEXT

Bazi Bushen capsule (BZBS) has anti-ageing properties and is effective in enhancing memory.

OBJECTIVE

To find evidence supporting the mechanisms and biomarkers by which BZBS functions.

MATERIALS AND METHODS

Male C57BL/6J mice were randomly divided into five groups: normal, ageing, β-nicotinamide mononucleotide capsule (NMN), BZBS low-dose (LD-BZ) and BZBS high-dose (HD-BZ). The last four groups were subcutaneously injected with d-galactose (d-gal, 100 mg/kg/d) to induce the ageing process. At the same time, the LD-BZ, HD-BZ and NMN groups were intragastrically injected with BZBS (1 and 2 g/kg/d) and NMN (100 mg/kg/d) for treatment, respectively. After 60 days, the changes in overall ageing status, brain neuron morphology, expression of p16^INK4a, proliferating cell nuclear antigen (PCNA), ionized calcium-binding adapter molecule 1 (Iba1), postsynaptic density protein 95 (PSD95), CD11b, Arg1, CD206, Trem2, Ym1 and Fizz1, and the senescence-associated secretory phenotype (SASP) factors were observed.

RESULTS

Compared with the mice in the ageing group, the HD-BZ mice exhibited obvious improvements in strength, endurance, motor coordination, cognitive function and neuron injury. The results showed a decrease in p16^INK4a, Iba1 and the upregulation of PCNA, PSD95 among brain proteins. The brain mRNA exhibited downregulation of Iba1 (p < 0.001), CD11b (p < 0.001), and upregulation of Arg1 (p < 0.01), CD206 (p < 0.05), Trem2 (p < 0.001), Ym1 (p < 0.01), Fizz1 (p < 0.05) and PSD95 (p < 0.01), as well as improvement of SASP factors.

CONCLUSIONS

BZBS improves cognitive deficits via inhibition of cellular senescence and microglia activation. This study provides experimental evidence for the wide application of BZBS in clinical practice for cognitive deficits.

Chronic Methylmercury Intoxication Induces Systemic Inflammation, Behavioral, and Hippocampal Amino Acid Changes in C57BL6J Adult Mice

Methylmercury (MeHg) is highly toxic to the human brain. Although much is known about MeHg neurotoxic effects, less is known about how chronic MeHg affects hippocampal amino acids and other neurochemical markers in adult mice. In this study, we evaluated the MeHg effects on systemic lipids and inflammation, hippocampal oxidative stress, amino acid levels, neuroinflammation, and behavior in adult male mice. Challenged mice received MeHg in drinking water (2 mg/L) for 30 days. We assessed weight gain, total plasma cholesterol (TC), triglycerides (TG), endotoxin, and TNF levels. Hippocampal myeloperoxidase (MPO), malondialdehyde (MDA), acetylcholinesterase (AChE), amino acid levels, and cytokine transcripts were evaluated. Mice underwent open field, object recognition, Y, and Barnes maze tests. MeHg-intoxicated mice had higher weight gain and increased the TG and TC plasma levels. Elevated circulating TNF and LPS confirmed systemic inflammation. Higher levels of MPO and MDA and a reduction in IL-4 transcripts were found in the hippocampus. MeHg-intoxication led to increased GABA and glycine, reduced hippocampal taurine levels, delayed acquisition in the Barnes maze, and poor locomotor activity. No significant changes were found in AChE activity and object recognition. Altogether, our findings highlight chronic MeHg-induced effects that may have long-term mental health consequences in prolonged exposed human populations.

Schisandrin alleviates the cognitive impairment in rats with Alzheimer’s disease by altering the gut microbiota composition to modulate the levels of endogenous metabolites in the plasma, brain, and feces

Schisandrin is one of the main active compounds isolated from the fruit of Schisandrae chinensis Fructus, which is scientifically proven to have beneficial effects on Alzheimer’s disease (AD) treatment at the cellular and whole organism level. However, the oral availability of schisandrin is very low, thus implying that the underlying mechanism of therapeutic effect on AD treatment is yet to be clarified fully. Therefore, we speculated that the therapeutic effect of schisandrin on AD is mainly by regulating the imbalance of the gut microbiota (GM). In this study, behavioral experiments and H&E staining were used to confirm the pharmacological effects of schisandrin on rats with AD. 16S rDNA gene sequencing and feces, plasma, and brain metabolomics techniques were utilized to investigate the therapeutic effects and the underlying mechanisms of schisandrin on cognitive impairment in rats with AD. The results indicated that schisandrin improved cognitive impairment and hippocampal cell loss in rats. The UPLC-QTOF/MS-based metabolomics studies of the feces, plasma, and brain revealed that 44, 96, and 40 potential biomarkers, respectively, were involved in the treatment mechanism of schisandrin. Schisandrin improved the metabolic imbalance in rats with AD, and the metabolic changes mainly affected the primary bile acid biosynthesis, sphingolipid metabolism, glycerophospholipid metabolism, and unsaturated fatty acid biosynthesis. Schisandrin can improve the GM structure disorder and increase the abundance of beneficial bacteria in the gut of rats with AD. The predictive metagenomics analysis indicated that the altered GM was mainly involved in lipid metabolism, steroid hormone biosynthesis, arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, and bacterial invasion of epithelial cells. Spearman’s correlation analysis showed a significant correlation between affected bacteria and metabolites in various metabolic pathways. Overall, the data underline that schisandrin improves the cognitive impairment in rats with AD by affecting the composition of the GM community, thus suggesting the potential therapeutic effect of schisandrin on the brain–gut axis in rats with AD at the metabolic level.

Cornuside ameliorates cognitive impairments in scopolamine induced AD mice: Involvement of neurotransmitter and oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis Sieb. et Zucc., traditional Chinese medicine, has been widely used in the treatment of dementia. Cornel iridoid glycosides of Cornus officinalis is therapeutic to Alzheimer's disease (AD), while its pharmacodynamic material basis is not clear. Cornuside, an iridoid glycoside extracted from of Cornus officinalis Sieb. et Zucc, might be a potential anti-AD candidate.

AIM OF THE STUDY

Cornuside was evaluated for its effect on scopolamine induced AD mice, and its action mechanisms were explored.

MATERIALS AND METHODS

ICR mice were administered with 1 mg/kg scopolamine intraperitoneally to induce amnesia. The therapeutic effect of cornuside of cognitive function was evaluated via series of behavioral tests, including Morris water maze test, step-through test and step-down test. In addition, specific enzyme reaction tests were used to detect the content of acetylcholine (ACh) and malondialdehyde (MDA), as well as the activities of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), choline acetyltransferase (ChAT), superoxide dismutase (SOD), catalase (CAT), monoamine oxidase (MAO) in the brain. The levels of monoamine neurotransmitters were detected by high performance liquid chromatography-electrochemical detection (HPLC-ECD).

RESULTS

Cornuside ameliorated the spatial memory impairment in Morris water maze test and cognitive disruption in step-through and step-down test. Furthermore, cornuside improved the level of ACh by reducing the activities of AChE and BuChE, and increasing the activity of ChAT in hippocampus. Cornuside also increased the levels of monoamine neurotransmitters by inhibiting MAO activity in hippocampus and cortex. In addition, cornuside attenuated MDA by enhancing the activities of SOD and CAT in hippocampus and cortex.

CONCLUSION

Cornuside improved cognitive dysfunction induced by scopolamine in behavioral tests. The mechanisms of cornuside were further investigated from the aspects of neurotransmitters and oxidative stress. Cornuside could inhibit oxidative stress and neurotransmitter hydrolases, increase ACh and monoamine neurotransmitters, which finally contributed to its therapeutic effect on scopolamine induced amnesia.

Explore the Therapeutic Composition and Mechanism of Schisandra chinensis-Acorus tatarinowii Schott on Alzheimer’s Disease by Using an Integrated Approach on Chemical Profile, Network Pharmacology, and UPLC-QTOF/MS-Based Metabolomics Analysis

Background. Alzheimer’s disease places a heavy economic burden to healthcare systems around the world. However, the effective treatments are still lacking. Traditional Chinese medicines (TCM) of Schisandra chinensis and Acorus tatarinowii Schott have the pharmacological effects of sedation and neuroprotection and have been clinically proven to be effective in the treatment of AD. However, their main anti-Alzheimer’s compounds and functional mechanisms remain unclear. Purpose. To elucidate the main therapeutic components and possible mechanisms of Sc-At in AD using a comprehensive strategy combining metabolomics and network pharmacology. Methods. First, the UPLC-QTOF/MS method was used to identify the main chemical constituents of Schisandra chinensis and Acorus tatarinowii Schott alcohol extracts in vitro and in vivo. Secondly, the theoretical active ingredients, targets, and pathways of Sc-At for AD treatment were predicted by network pharmacology methods. Finally, plasma metabolomics were detected by UPLC-QTOF/MS to analyze the differential metabolites and metabolic pathways related to Sc-At. Based on the analyses above, the anti-AD mechanism of Sc-At was explored. Results. A total of 95 chemical components were identified in Sc-At extracts in vitro, and 34 prototype drug components were detected in rat plasma; network pharmacology screening identified 14 drug components in line with the principle of Lipinski, of which 10 were present for in vitro drug composition analysis. For these 10 components, 58 AD disease targets were predicted, and 85 AD-related KEGG signaling pathways were enriched. Six core biomarkers of Sc-At (cis-8,11,14,17-eicosatetraenoic acid, prostaglandin H2, sphingosine 1-phosphate, enol-phenylpyruvate, 3-methoxytyrosine, and pristanoyl-CoA) were regulated to a normal state during the treatment of AD. Conclusion. The mechanism of Sc-At for the treatment of AD can be achieved by the effect of the 10 compounds of Sc-At on TNF, MAPK8, MAPK14, PTGS1, and other targets, thereby affecting arachidonic acid metabolism, neurotransmitters, and sphingolipid metabolism.

Schizandrin A ameliorates cognitive functions via modulating microglial polarisation in Alzheimer's disease mice

CONTEXT

Schizandrin A (Sch A) is a major phytochemical from Schisandra chinensis (Turcz.) Baill. (Schisandraceae), which exerts a neuroprotective effect in Alzheimer's disease (AD).

OBJECTIVE

To investigate the mechanism of Sch A in AD.

MATERIALS AND METHODS

AD group: APP/PS1 transgenic mice served as AD models; AD + SCH group: APP/PS1 received 2 mg/kg Sch A by intragastric administration; WT: C57BL/6 mice were used as control. For in vitro assay, mouse microglial BV2 cells were treated with 0.5 µg/mL lipopolysaccharide or combined with 10 μmol/L Sch A for 24 h. The cognitive function and apoptosis in the mice was estimated. Microglial polarisation in the mice and cells was analysed.

RESULTS

Sch A treatment effectively improved spatial learning and memory ability and suppressed apoptosis in the brain tissues of APP/PS1 mice. APP/PS1 mice exhibited an increase in the levels of Aβ1-42 (2367.9 ± 431.1 pg/mg) and Aβ1-40 (1753.3 ± 253.4 pg/mg), which was abolished by Sch A treatment. Moreover, Sch A treatment repressed the proportions of iNOS⁺/Iba-1⁺ cells and IL-6 expression, while enhanced the proportions of Arg-1⁺/Iba-1⁺ cells and IL-10 expression in APP/PS1 mice. In vitro, Sch A treatment reduced the proportions of CD16/32⁺ cells, iNOS expression and IL-6 levels (25.7 ± 5.3 pg/mL) repressed M1 polarisation, and enhanced the proportions of CD206 cells, Arg-1 expression and IL-10 levels (75.9 ± 12.8 pg/mL) in BV2 cells.

CONCLUSIONS

This research confirms the neuroprotective effect of Sch A in AD, suggesting that Sch A may become a potential anti-AD agent.

Pharmacokinetic study of Ninjin'yoeito: Absorption and brain distribution of Ninjin'yoeito ingredients in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Ninjin'yoeito (NYT), a Japanese traditional Kampo medicine, has been reported to exert various clinical benefits such as relief from fatigue, malaise, anorexia, frailty, sarcopenia, and cognitive dysfunction. Recently, some review articles described the pharmacological effects of NYT and additionally indicated the possibility that multiple ingredients in NYT contribute to these effects. However, pharmacokinetic data on the ingredients are essential in addition to data on their pharmacological activities to accurately determine the active ingredients in NYT.

AIM OF THE STUDY

This study assessed the in vivo pharmacokinetics of NYT using mice.

MATERIALS AND METHODS

Target liquid chromatography-mass spectrometry (LC-MS) and wide target LC-MS or LC-tandem MS of NYT ingredients in plasma and the brain after oral administration of NYT were performed. Imaging MS was performed to investigate the detailed brain distributions of NYT ingredients.

RESULTS

The concentrations of 13 ingredients in plasma and schizandrin in the brain were quantified via target LC-MS, and the wide target analysis illustrated that several ingredients are absorbed into blood and transported into the brain. Imaging MS revealed that schizandrin was homogenously dispersed in the NYT-treated mouse brain.

CONCLUSION

These results should be useful for clarifying the active ingredients of NYT and their mechanisms of actions.

Pharmacokinetic and metabolomics approach based on UHPLC-MS to evaluate therapeutic effect of lignans from S. Chinensis in alzheimer's disease

Lignans from Schisandra chinensis (Turcz.) Baill (LFS) has been proved to improve impaired cognitive ability thereby show potential in treating Alzheimer's disease (AD). In this study, UHPLC-Q-TOF-MS and UHPLC-QQQ-MS were adopted cooperatively to establish a method synchronously detecting 10 kinds of LFS monomers in rat plasma samples. And this method was further applied for pharmacokinetic study to compare the metabolism of LFS in normal and AD rats. The results indicated that AD rats showed an observably better absorption of LFS compared to normal rats. Based on time-varying plasma concentration of LFS, metabolomics was used to establish a plasma concentration-time-endogenous metabolite connection. In total 54 time-varying endogenous metabolites were screened and most of which were closely associated with AD. And LFS exerted a concentration dependent regulating effect to most of these metabolites. Through biomarker related pathways and biological function analysis, LFS might treat AD through neuroprotection, antioxidant damage and regulating the metabolism of unsaturated fatty acids. This is the first study connecting LFS absorbtion and endogenous metabolite changes with the time lapse. The pharmacokinetics and metabolic profile differences between normal and AD rats were firstly investigated as well. This study provides a novel perspective in exploring the effect and mechanism of LFS in treating AD.

Schisandrol A Suppresses Catabolic Factor Expression by Blocking NF-κB Signaling in Osteoarthritis

Schisandrol A possesses pharmacological properties and is used to treat various diseases; however, its effects on osteoarthritis (OA) progression remain unclear. Here, we investigated Schisandrol A as a potential therapeutic agent for OA. In vitro, Schisandrol A effects were confirmed based on the levels of expression of catabolic factors (MMPs, ADAMTS5, and Cox2) induced by IL-1β or Schisandrol A treatment in chondrocytes. In vivo, experimental OA in mice was induced using a destabilized medial meniscus (DMM) surgical model or oral gavage of Schisandrol A in a dose-dependent manner, and demonstrated using histological analysis. In vitro and in vivo analyses demonstrated that Schisandrol A inhibition attenuated osteoarthritic cartilage destruction via the regulation of Mmp3, Mmp13, Adamts5, and Cox2 expression. In the NF-κB signaling pathway, Schisandrol A suppressed the degradation of IκB and the phosphorylation of p65 induced by IL-1β. Overall, and Schisandrol A reduced the expression of catabolic factors by blocking NF-κB signaling and prevented cartilage destruction. Therefore, Schisandrol A attenuated OA progression, and can be used to develop novel OA drug therapies.

Losartan Improves Memory, Neurogenesis and Cell Motility in Transgenic Alzheimer's Mice

Angiotensin receptor blockers (ARBs) have demonstrated multiple neuroprotective benefits in Alzheimer’s disease (AD) models. However, their beneficial effects on memory deficits, cholinergic activity, neurogenesis and Amyloid beta (Aβ) clearance reveal significant interstudy variability. The delivery route can impact not only delivery but also targeting and therapeutic efficacy of ARBs. Our previous findings on the beneficial effects of intranasally delivered losartan in the APP/PS1 model of AD prompted us to explore the influence of the delivery route by employing here the systemic administration of losartan. Consistent with our previous results with intranasal losartan, repeated intraperitoneal administration (10 mg/kg) resulted in a remarkable decrease in Aβ plaques and soluble Aβ42, as well as inflammatory cytokines (IL-2, IL-6 and TNFα). The Aβ reduction can be ascribed to its facilitated degradation by neprilysin and diminished generation by BACE1. Losartan increased neurogenesis in vivo and in vitro and improved migratory properties of astrocytes isolated from adult transgenic AD mice. In summary, this data together with our previous results suggest therapeutic features of losartan which are independent of delivery route. The improvement of cell motility of Aβ-affected astrocytes by losartan deserves further in vivo investigation, which may lead to new strategies for AD treatment.

Schisandrin Inhibits NLRP1 Inflammasome-Mediated Neuronal Pyroptosis in Mouse Models of Alzheimer's Disease

BACKGROUND

In recent years, schisandrin (SCH) was proved to improve Alzheimer's Disease (AD). The aim of our study is to explore the effect of SCH on neuronal pyroptosis in the disease.

METHODS

A Morris water maze test was performed to evaluate the spatial learning and memory retention of AD mouse. ELISA was fulfilled to examine the concentration of Aβ, IL-1β, and IL-18. Western blot was performed to detect the expression of apoptosis- and pyroptosis-related proteins. Besides, the neuronal apoptosis rate was examined using TUNEL assay. Immunohistochemistry was utilized to detect the activation of NLRP1 inflammasome.

RESULTS

Here, AD mice have serious cognitive impairment. Meantime, Aβ was highly expressed in the brains of AD mice. SCH could effectively rescue the cognitive impairment in AD mice and impede the production of Aβ. Subsequently, we further demonstrated that SCH repressed neuronal apoptosis, pyroptosis-related proteins expression, and the activation of NLRP1 inflammasome in the hippocampus of AD mice. We also proved that Aβ induced neuronal apoptosis and pyroptosis in vitro. However, the effects of Aβ on neuronal apoptosis and pyroptosis were partly reversed by SCH treatment.

CONCLUSION

Overall, our data indicated that SCH improved cognitive impairment in AD mice through inhibition of NLRP1 inflammasome-mediated neuronal pyroptosis and neuronal apoptosis. Our works provided new evidence to support SCH acting as a potential treatment method in AD.

The involvement of NLRP3 inflammasome in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases, and it is characterised by progressive deterioration in cognitive and memory abilities, which can severely influence the elderly population's daily living abilities. Although researchers have made great efforts in the field of AD, there are still no well-established strategies to prevent and treat this disease. Therefore, better clarification of the molecular mechanisms associated with the onset and progression of AD is critical to provide a theoretical basis for the establishment of novel preventive and therapeutic strategies. Currently, it is generally believed that neuroinflammation plays a key role in the pathogenesis of AD. Inflammasome, a multiprotein complex, is involved in the innate immune system, and it can mediate inflammatory responses and pyroptosis, which lead to neurodegeneration. Among the various types of inflammasomes, the NLRP3 inflammasome is the most characterised in neurodegenerative diseases, especially in AD. The activation of the NLRP3 inflammasome causes the generation of caspase-1-mediated interleukin (IL)-1β and IL-18 in microglia cells, where neuroinflammation is involved in the development and progression of AD. Thus, the NLRP3 inflammasome is likely to be a crucial therapeutic molecular target for AD via regulating neuroinflammation. In this review, we summarise the current knowledge on the role and regulatory mechanisms of the NLRP3 inflammasome in the pathogenic mechanisms of AD. We also focus on a series of potential therapeutic treatments targeting NLRP3 inflammasome for AD. Further clarification of the regulatory mechanisms of the NLRP3 inflammasome in AD may provide more useful clues to develop novel AD treatment strategies.

Benzo(a)pyrene exposure induced neuronal loss, plaque deposition, and cognitive decline in APP/PS1 mice

Background

Exposure to benzo(a)pyrene (BaP) was associated with cognitive impairments and some Alzheimer’s disease (AD)-like pathological changes. However, it is largely unknown whether BaP exposure participates in the disease progression of AD.

Objectives

To investigate the effect of BaP exposure on AD progression and its underlying mechanisms.

Methods

BaP or vehicle was administered to 4-month-old APPswe/PS1dE9 transgenic (APP/PS1) mice and wildtype (WT) mice for 2 months. Learning and memory ability and exploratory behaviors were evaluated 1 month after the initiation/termination of BaP exposure. AD-like pathological and biochemical alterations were examined 1 month after 2-month BaP exposure. Levels of soluble beta-amyloid (Aβ) oligomers and the number of Aβ plaques in the cortex and the hippocampus were quantified. Gene expression profiling was used to evaluate alternation of genes/pathways associated with AD onset and progression. Immunohistochemistry and Western blot were used to demonstrate neuronal loss and neuroinflammation in the cortex and the hippocampus. Treatment of primary neuron-glia cultures with aged Aβ (a mixture of monomers, oligomers, and fibrils) and/or BaP was used to investigate mechanisms by which BaP enhanced Aβ-induced neurodegeneration.

Results

BaP exposure induced progressive decline in spatial learning/memory and exploratory behaviors in APP/PS1 mice and WT mice, and APP/PS1 mice showed severer behavioral deficits than WT mice. Moreover, BaP exposure promoted neuronal loss, Aβ burden and Aβ plaque formation in APP/PS1 mice, but not in WT mice. Gene expression profiling showed most robust alteration in genes and pathways related to inflammation and immunoregulatory process, Aβ secretion and degradation, and synaptic formation in WT and APP/PS1 mice after BaP exposure. Consistently, the cortex and the hippocampus of WT and APP/PS1 mice displayed activation of microglia and astroglia and upregulation of inducible nitric oxide synthase (iNOS), glial fibrillary acidic protein (GFAP), and NADPH oxidase (three widely used neuroinflammatory markers) after BaP exposure. Furthermore, BaP exposure aggravated neurodegeneration induced by aged Aβ peptide in primary neuron-glia cultures through enhancing NADPH oxidase-derived oxidative stress.

Conclusion

Our study showed that chronic exposure to environmental pollutant BaP induced, accelerated, and exacerbated the progression of AD, in which elevated neuroinflammation and NADPH oxidase-derived oxidative insults were key pathogenic events.

Schisandrin ameliorates cognitive deficits, endoplasmic reticulum stress and neuroinflammation in streptozotocin (STZ)-induced Alzheimer's disease rats

Schisandrin, an active component extracted from Schisandra chinensis (Turcz.) Baill has been reported to alleviate the cognitive impairment in neurodegenerative disorder like Alzheimer’s disease (AD). However, the mechanism by which schisandrin regulates the cognitive decline is still unclear. In our study, intracerebroventricular injection of streptozotocin (STZ) was employed to establish AD model in male Wistar rats, and indicated dose of schisandrin was further administered. The Morris water maze test was performed to evaluate the ability of learning and memory in rats with schisandrin treatment. The results indicated that schisandrin improved the capacity of cognition in STZ-induced rats. The contents of pro-inflammatory cytokines in brain tissue were determined by ELISA, and the expressions of these cytokines were assessed by western-blot and immunohistochemistry. The results showed that treatment of schisandrin significantly reduced the production of inflammation mediators including tumor necrosis factor-α, interleukin-1β and interleukin-6. Further study suggested a remarkable decrease in the expressions of ER stress maker proteins like C/EBP-homologous protein, glucose-regulated protein 78 and cleaved caspase-12 in the presence of schisandrin, meanwhile the up-regulation of sirtuin 1 (SIRT1) was also observed in the same group. Additionally, the results of western-blot and EMSA demonstrated that schisandrin inhibited NF-κB signaling in the brain of STZ-induced rats. In conclusion, schisandrin ameliorated STZ-induced cognitive dysfunction, ER stress and neuroinflammation which may be associated with up-regulation of SIRT1. Our study provides novel mechanisms for the neuroprotective effect of schisandrin in AD treatment.

Alpinia oxyphylla-Schisandra chinensis Herb Pair Alleviates Amyloid-β Induced Cognitive Deficits via PI3K/Akt/Gsk-3β/CREB Pathway

Alzheimer's disease (AD), one of the most common neurodegenerative diseases, threatens people's health. Based on the theory of traditional Chinese medicine (TCM) efficacy and treatment theory, we first proposed the Alpinia oxyphylla-Schisandra chinensis herb pair (ASHP) for finding a candidate of AD treatment. This study aimed at exploring the effects of ASHP on improving the cognitive function and neurodegeneration, and revealing the possible mechanism. In this study, an amyloid-β (Aβ) induced AD model was established in mice via intracerebroventricular injection. The Y-maze test and Morris water maze test were carried out to observe the behavioral change of mice, which showed that ASHP significantly ameliorated cognitive impairment. In addition, ASHP reduced amyloid-β deposition and downregulated the hyperphosphorylation of tau via immunofluorescence assay and western blot analysis, respectively. Subsequently we focused on the PI3K/Akt pathway that is a classical pathway related to nervous system diseases. It also noticeably ASHP improved the histopathological changes in the hippocampus and cortex. Moreover, it was found that ASHP could upregulate the PI3K/Akt/Gsk-3β/CREB signaling pathway in N2a-SwedAPP cells. Taken together, it suggests that ASHP might reverse cognitive deficits and neurodegeneration via PI3K/Akt/Gsk-3β/CREB pathway.

A systematic strategy for screening therapeutic constituents of Schisandra chinensis (Turcz.) Baill infiltrated blood-brain barrier oriented in lesions using ethanol and water extracts: a novel perspective for exploring chemical material basis of herb medicines

Schisandra chinensis, a widely used Chinese herbal medicine, was considered as central nervous system (CNS) drug for years. Both ethanol extracts (EES) and water extracts (WES) of it were applied clinically. Unfortunately, the difference of their efficacy and even effective material foundation of S. chinensis remains obscure. In this study, to explore the active constituents of S. chinensis, we compared pharmacodynamics and chemical profiles in vitro/in vivo of EES/WES for the first time using multiple chemical analysis, pharmacological and data processing approaches. It was proved that there was no significant difference in the anti-depressive effects between WES and EES. However, the contents of most components in vitro and in plasma were higher in EES than those in WES, which was unconvincing for their similar efficacy. Therefore, we further explored components of S. chinensis targeted onto brain and the results showed that 5 lignans were identified with definite absorptivity respectively both in EES and WES caused by the limitation of blood−brain barrier. Moreover, bioinformatic analysis predicted their anti-depressive action. Above all, the systematic strategy screened 5 brain-targeted effective substances of S. chinensis and it was suggested that exploring the components into nidi would promote the studies on herbs effective material basis.

Combination of schisandrin and nootkatone exerts neuroprotective effect in Alzheimer's disease mice model

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases which seriously affect the quality of life of the elderly. Schisandrin (SCH) and nootkatone (NKT) are the two marked active components in ASHP. In this study, the effects of Alpinia oxyphylla-Schisandra chinensis herb pair (ASHP) as well as its bioactive components on cognitive deficiency and dementia were revealed via Aβ_1-42-induced AD in mouse. Morris water maze test showed that acute administration of ASHP and SCH + NKT treatments had higher discrimination index in the object recognition task, more quadrant dwell time and shorter escape latency compared with those in the Morris water maze. The levels of TNF-α, IL-1β and IL-6 were decreased after ASHP and SCH + NKT treatment. The inflammatory response was attenuated by inhibiting TLR4/ NF-κB/ NLRP3 pathway. In addition, ASHP and SCH + NKT treatments significantly restored the activities of superoxide dismutase (SOD), glutathione S-transferase (GST), cyclooxygenase-2 (COX-2), total antioxidant capacity (T-AOC) and inducible nitric oxide syntheses (iNOS), and the levels of glutathione (GSH), malondialdehyde (MDA) and nitric oxide (NO). The histopathological changes of hippocampus were noticeably improved after ASHP and SCH + NKT treatments. These findings demonstrate that ASHP as well as its bioactive components exerted a protective effects on cognitive disorder, inflammatory reaction and oxidative stress.

The protective underlying mechanisms of Schisandrin on SH-SY5Y cell model of Alzheimer's disease

The extract of Schisandrin a traditional Chinese medicine was postulated to be effective in prevention and treatment of Alzheimer's disease (AD). The aim of this study was to examine the underlying protective actions of Schizandrin using a human neuroblastoma cell line (SH-SY5Y). In particular Schizandrin-mediated effects on expression of glycogen synthase kinase (GSK)-3β, protein kinase B (Akt) and Tau protein, known to be altered in AD were determined. In preliminary assays, various concentrations of Schisandrin were incubated SH-SY5Y cells to establish effects on cell viability and potential toxicity in further experimentation. Amyloid-β (Aβ_1-42) peptide 10 μmol/L was used to induce in vitro AD model in SH-SY5Y. Exposure to Aβ_1-42 significantly reduced cell viability. Treatment with Schisandrin to Aβ_1-42 exposed cells increased cell viability compared to amyloid peptide; however only the 10 μmol/L Schisandrin concentration was effective in restoring cell viability to control. Western blot analysis demonstrated that Aβ_1-42 produced a significant decrease in p-Akt protein expression levels accompanied by marked elevation in p-tau and p-GSK-3β protein expression levels. Addition of 10 μmol/L Schisandrin to amyloid-treated SH-SY5Y cells was found to significantly increase protein expression levels of p-Akt associated with reduction in expression levels of p-tau and p-GSK-3β protein. Treatment with 10 μmol/L Schisandrin of SH-SY5Y cells with the p-Akt inhibitor LY294002 demonstrated that the herbal-induced rise in p-Akt protein expression was diminished by this inhibitor indicating that signal transduction occurred in the observed cellular effects. Evidence indicates that Schisandrin inhibition of Aβ_1-42 -mediated cellular damage in AD neurons may involve activation of the PI3K/Akt signaling pathway where up-regulation of p-Akt activity consequently leads downstream to decreased activity of p-GSK-3β phosphorylation accompanied by reduced tau protein. Consequently, restoration of neuronal cell viability was noted. Our findings suggest that the use of Schisandrin may be considered beneficial as a therapeutic agent in AD.

Synergistic Neuroprotective Effect of Schisandra chinensis and Ribes fasciculatum on Neuronal Cell Death and Scopolamine-Induced Cognitive Impairment in Rats

Mild cognitive impairment (MCI) is considered as a transitional stage between aging and Alzheimer’s disease. In the present study, we examined the protective effect of Schisandra chinensis (SC) and Ribes fasciculatum (RF) on neuronal cell death in vitro and scopolamine-induced cognitive impairment in Sprague Dawley^® rats in vivo. A mixture of SC and RF extracts (SC+RF) significantly protected against hydrogen peroxide-induced PC12 neuronal cell death. The neuroprotective effect of SC+RF on scopolamine-induced memory impairment in rats was evaluated using the passive avoidance test and the Morris water maze test. In the passive avoidance test, SC+RF-treated rats showed an increased latency to escape, compared to the scopolamine-treated rats. Moreover, SC+RF treatment significantly reduced escape latency in water maze test, compared to treatment with scopolamine alone. To verify the long-term memory, we performed probe test of water maze test. As a result, rat treated with SC+RF spent more time in the target quadrant. Consistent with enhancement of memory function, the brain derived neurotrophic factor (BDNF) and its downstream molecules (pERK, pATK, and pCREB) are increased in SC+RF treatment in hippocampal area compared with scopolamine treated group. These results suggest that a mixture of SC and RF extracts may be a good therapeutic candidate for preventing mild cognitive impairment.

Determination of endogenous substance change in PM2.5-induced rat plasma and lung samples by UPLC-MS/MS method to identify potential markers for lung impairment

Exposure to fine particulate matter (PM_2.5) could induce lung impairment aggravation. Moreover, endogenous substances are known to play a significant role in lung impairment. Therefore, the research objectives was to investigate the influence of PM_2.5-induced lung impairment on the levels of the eight endogenous substances, γ-aminobutyric acid (GABA), acetylcholine (ACh), glutamate (Glu), serotonin (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), noradrenaline (NE), dopamine (DA), and 3, 4-dihydroxyphenylacetic acid (DOPAC). A sensitive UPLC-MS/MS method for the simultaneous determination of these endogenous substances in rat plasma and lung tissues was developed. The validated method was successfully applied for comparing profiles of analytes in rat plasma and lung tissues. The results indicated that five endogenous substances, namely, GABA, Ach, Glu, DA, and DOPAC, had a significant change in the rats with PM_2.5-induced lung impairment.

Impairment of Dendrodendritic Inhibition in the Olfactory Bulb of APP/PS1 Mice

Olfactory dysfunction is an early event in Alzheimer’s disease (AD). However, the mechanism underlying the AD-related changes in the olfactory bulb (OB) remains unknown. Granule cells (GCs) in the OB regulate the activity of mitral cells (MCs) through reciprocal dendrodendritic synapses, which is crucial for olfactory signal processing and odor discrimination. Nevertheless, the relationships between the morphological and functional changes of dendrodendritic synapses, particularly the local field potentials (LFPs) as a consequence of olfactory disorders in patients with AD have not been investigated. Here, we studied the morphological and functional changes induced by dendrodendritic inhibition in GCs onto MCs in the OB of amyloid precursor protein (APP)/PS1 mice and age-matched control mice during aging, particular, we focused on the effects of olfactory disorder in the dendrodendritic synaptic structures and the LFPs. We found that olfactory disorder was associated with increased amyloid-β (Aβ) deposits in the OB of APP/PS1 mice, and those mice also exhibited abnormal changes in the morphology of GCs and MCs, a decreased density of GC dendritic spines and impairments in the synaptic interface of dendrodendritic synapses between GCs and MCs. In addition, the aberrant enhancements in the γ oscillations and firing rates of MCs in the OB of APP/PS1 mice were recorded by multi-electrode arrays (MEAs). The local application of a GABA_AR agonist nearly abolished the aberrant increase in γ oscillations in the external plexiform layer (EPL) at advanced stages of AD, whereas a GABA_AR antagonist aggravated the γ oscillations. Based on our findings, we concluded that the altered morphologies of the synaptic structures of GCs, the dysfunction of reciprocal dendrodendritic synapses between MCs and GCs, and the abnormal γ oscillations in the EPL might contribute to olfactory dysfunction in AD.

Schisandra chinensis Fructus and Its Active Ingredients as Promising Resources for the Treatment of Neurological Diseases

Neurological diseases (NDs) are a leading cause of death worldwide and tend to mainly affect people under the age of 50. High rates of premature death and disability caused by NDs undoubtedly constrain societal development. However, effective therapeutic drugs and methods are very limited. Schisandra chinensis Fructus (SCF) is the dry ripe fruit of Schisandra chinensis (Turcz.) Baill, which has been used in traditional Chinese medicine for thousands of years. Recent research has indicated that SCF and its active ingredients show a protective role in NDs, including cerebrovascular diseases, neurodegenerative diseases, or depression. The key neuroprotective mechanisms of SCF and its active ingredients have been demonstrated to include antioxidation, suppression of apoptosis, anti-inflammation, regulation of neurotransmitters, and modulation of brain-derived neurotrophic factor (BDNF) related pathways. This paper summarizes studies of the role of SCF and its active ingredients in protecting against NDs, and highlights them as promising resources for future treatment. Furthermore, novel insights on the future challenges of SCF and its active ingredients are offered.