Protective effect of Schisandra chinensis lignans on hypoxia-induced PC12 cells and signal transduction

Schisandra total lignans ameliorate neuronal ferroptosis in 3xTg-AD mice via regulating NADK/NADPH/GSH pathway

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with limited treatments. Schisandra total lignans (STL), the primary active component of Schisandra chinensis, shows potential in alleviating AD-related symptoms, though the mechanisms remain unclear.

PURPOSE

Considering the promoting effect of neuronal ferroptosis on AD and the neuroprotective activity of STL, this study aimed to investigate the impact of STL on AD neuronal ferroptosis and elucidate its underlying mechanisms.

METHODS

This study used 3xTg-AD mice and SH-SY5Y cells overexpressing APPswe as models. UHPLC/Q-TOF-MS was applied for identifying components in STL extract and the plasma of 3xTg-AD mice, as well as to detect cellular endogenous metabolites for one-carbon metabolism analysis. Behavioral tests, including the Y maze, novel object recognition, Morris water maze, and open field, were conducted to assess the cognitive function and emotional state. Histopathological examinations were performed using immunofluorescence, immunohistochemistry, Nissl staining, and transmission electron microscopy. The GSH, GSSG, NAD(H), NADP(H), and MDA levels, as well as GPX and GR activity were measured using assay kits. ROS, Fe2+, and lipid peroxidation levels were detected with probes. Protein expression was evaluated by Western blot. Molecular docking, molecular dynamics simulations and cellular thermal shift assay were performed to analyze the STL-NADK interactions.

RESULTS

Behavioral tests indicated that STL alleviated cognitive impairments and anxiety in 3xTg-AD mice. Histological analysis showed that STL decreased hippocampal Aβ levels, inhibited hippocampal neuronal ferroptosis, and mitigated synaptic damage. Cellular assays demonstrated that STL alleviated APPswe overexpression-induced ferroptosis and synaptic damage by activating the NADK/NADPH/GSH pathway, with NADK knockdown abolishing this neuroprotective effect of STL. Computational analysis and cellular thermal shift assay identified Gomisin D as the key STL component with strong affinity for NADK, driving its neuroprotective effects.

CONCLUSION

NADK emerges as a novel potential therapeutic target for AD, with STL activating NADK, promoting NADPH and GSH production, thereby mitigating neuronal ferroptosis in AD.

Evaluation of traditional Chinese medicine tea bag TBDESJS in patients with Sjögren's syndrome and dry eye syndrome: A phase II pilot study

ETHNOPHARMACOLOGICAL RELEVANCE

Sjögren's syndrome (SJS) and dry eye syndrome (DES) are characterized by ocular dryness from inadequate tear production or excessive evaporation. To evaluate the effectiveness of TBDESJS (Chun-Yu-Ching-Hua-Yin, CYCHY), a TCM tea bag, in treating SJS and DES patients compared with healthy controls (NHC).

MATERIALS AND METHODS

This phase II pilot study included 100 participants (60 SJS, 30 DES, 10 NHC) across 8 weeks, assessing changes in Schirmer's test, OSDI, ESSPRI, PSQI, FIRST, and artificial tear usage, using repeated measurement ANOVA and Tukey's honestly significant difference (HSD) for analysis.

RESULTS

Total 97 subjects completed the trial, for the left eye (OS) of Schirmer's test, significant improvements at 4, and 8 weeks were observed in SJS (0.13 ± 0.43-5.77 ± 2.87, and 7.60 ± 4.84 mm) and DES (0.21 ± 0.41-6.21 ± 2.97, and 7.86 ± 3.47 mm) (all p < .001). For the right eye (OD), significant improvements were observed in SJS (0.13 ± 0.39-6.77 ± 4.53, and 8.79 ± 5.92 mm) and DES (0.34 ± 0.55-6.59 ± 2.50, and 8.24 ± 3.42 mm) (all p < .001). Secondary outcomes showed reduced the dryness of ESSPRI scores in SJS (6.37 ± 1.97-5.57 ± 1.79, p < .001) and DES (6.10 ± 1.97-5.28 ± 2.23, p < .05). PSQI global scores improved significantly in all groups at 8 weeks (p < .05). Artificial tear usage decreased in SJS (4.93 ± 2.45-1.00 ± 0.82 times/day), DES (4.47 ± 1.99-0.66 ± 0.67 times/day) (all p < .001). No serious adverse events in this study.

CONCLUSION

TBDESJS significantly improved tear production, ocular dryness, and sleep quality, indicating potential neural regulation, anti-inflammatory and immunomodulatory benefits. These findings advocate for TBDESJS (Chun-Yu-Ching-Hua-Yin, CYCHY)'s comprehensive therapeutic value in SJS and DES treatment, emphasizing the need for further research to understand long-term effects and mechanisms.

Establishment of a pharmacokinetics and pharmacodynamics model of Schisandra lignans against hippocampal neurotransmitters in AD rats based on microdi-alysis liquid chromatography-mass spectrometry

Objective: Our previous studies substantiated that the biological activity of Schisandra chinensis lignans during the treatment of Alzheimer's disease (AD) was mediated by neurotransmitter levels, and 15 of its active components were identified. However, the pharmacokinetic and pharmacodynamic relationship of Schisandra chinensis lignans has been less studied. The objective of this study was to investigate the relationship between the pharmacokinetics and pharmacodynamics of Schisandra chinensis lignans in the treatment of AD, and to establish a pharmacokinetic-pharmacodynamic (PK-PD) model. Methods and Results: Herein, we established a microdialysis-ultra performance liquid chromatography-triple quadruple mass spectrometry (MD-LC-TQ-MS) technique that could simultaneously and continuously collect and quantitatively analyze the active compounds and neurotransmitters related to the therapeutic effects of Schisandra chinensis in awake AD rats. Eight lignans were detected in the hippocampus, and a PK-PD model was established. The fitted curves highlighted a temporal lag between the maximum drug concentration and the peak drug effect. Following treatment, the levels of four neurotransmitters tended to converge with those observed in the sham operation group. Conclusion: By establishing a comprehensive concentration-time-effect relationship for Schisandra chinensis lignans in AD treatment, our study provides novel insights into the in vivo effects of these lignans in AD rats.

Optimization of Fermentation Process of Pomegranate Peel and Schisandra Chinensis and the Biological Activities of Fermentation Broth: Antioxidant Activity and Protective Effect Against H2O2-induced Oxidative Damage in HaCaT Cells

In this study, the lactobacillus fermentation process of pomegranate (Punica granatum L.) peel and Schisandra chinensis (Turcz.) Baill (PP&SC) was optimized by using the response surface method (RSM) coupled with a Box-Behnken design. The optimum fermentation condition with the maximal yield of ellagic acid (99.49 ± 0.47 mg/g) was as follows: 1:1 (w:w) ratio of pomegranate peel to Schisandra chinensis, 1% (v:v) of strains with a 1:1 (v:v) ratio of Lactobacillus Plantarum to Streptococcus Thermophilus, a 37 °C fermentation temperature, 33 h of fermentation time, 1:20 (g:mL) of a solid–liquid ratio and 3 g/100 mL of a glucose dosage. Under these conditions, the achieved fermentation broth (FB) showed stronger free radical scavenging abilities than the water extract (WE) against the ABTS⁺, DPPH, OH⁻ and O₂⁻ radicals. The cytotoxicity and the protective effect of FB on the intracellular ROS level in HaCaT cells were further detected by the Cell Counting Kit-8 (CCK-8) assay. The results showed that FB had no significant cytotoxicity toward HaCaT cells when its content was no more than 8 mg/mL. The FB with a concentration of 8 mg/mL had a good protective effect against oxidative damage, which can effectively reduce the ROS level to 125.94% ± 13.46% (p < 0.001) compared with 294.49% ± 11.54% of the control group in H₂O₂-damaged HaCaT cells. The outstanding antioxidant ability and protective effect against H₂O₂-induced oxidative damage in HaCaT cells promote the potential for the FB of PP&SC as a functional raw material of cosmetics.

Silencing MEG3 protects PC12 cells from hypoxic injury by targeting miR-21

Increasing number of literatures highlighted lncRNA maternally expressed gene 3 (MEG3) as an emerging target for hypoxic-ischaemic brain damage (HIBD). This study attempted to assess the role of MEG3 in a cell model of HIBD. Expression of MEG3 in PC12 cells was suppressed by siRNA-mediated transfection, after which the cells were subjected to hypoxia. Cell viability, apoptosis, migration and the expression of related proteins were assessed. Furthermore, the downstream gene of MEG3 and its downstream signalling pathways were explored. We found that, down-regulation of MEG3 prevented hypoxic injury in PC12 cells, as hypoxia induced viability loss, apoptosis and migration repression were attenuated by transfection with MEG3 siRNA. Meanwhile, MEG3 acted as a miR-21 sponge. The neuroprotective functions of MEG3 silence were flattened when miR-21 was suppressed. Moreover, the deactivation of PI3K/AKT pathway and the activation of NF-κB pathway induced by hypoxia were attenuated by MEG3 silence. As expected, the effects of MEG3 silence on these two signalling were via miR-21. In conclusion, the neuroprotective effects of MEG3 silence on PC12 cells injured by hypoxia were observed in this study. Mechanistically, the neuroprotective effects of MEG3 silence on PC12 cells were via sponging miR-21 and thus regulating PI3K/AKT and NF-κB pathways.HIGHLIGHTSMEG3 is highly expressed in PC12 cells following hypoxic injury;Silence of MEG3 prevents hypoxia-induced cell damage in PC12 cells;MEG3 acts as a miR-21 sponge;MEG3 sponges miR-21 to regulate PI3K/AKT and NF-κB pathways.

The Quality Control of Both Schisandra chinensis (Turcz.) Baill and Schisandra sphenanthera Rehd. Et Wils by Rapid Resolution Liquid Chromatography (RRLC)

Quality problems with Schisandra chinensis (Turcz.) Baill (SCB) and Schisandra sphenanthera Rehd.et Wils. (SSR) have been increasing owing to their obvious difference in supply and demand. In this study, qualitative and quantitative studies were carried out on the contents of various components of SCB and SSR, which provided the reference for the quality control of the raw materials of SCB and SSR. A ZORBAX Eclipse Plus C18 column (1.8 μm, 100 mm × 2.1 mm) was used with a column temperature of 40 °C, a mobile phase consisting of a gradient of acetonitrile and water, a flow rate of 0.3 mL/min, and an injection sample of 1 µL. Ultraviolet detection was operated at 220 nm throughout the analyzing time. Almost all the compounds achieved baseline separation. In addition, this method showed a favorable recovery (98.3%-102.5% for SCB and 99.1%-100.5% for SSR) and good precision and stability, confirming the reliability of the experimental data.

Comparative evaluation of Schisandra chinensis and Viscum album var. coloratum (Korean mistletoe) powders on growth performance, carcass characteristics, serum cholesterol profiles, and meat quality of broilers

Experiments were conducted to compare the effects of Schisandra chinensis and Viscum album var. coloratum (Korean mistletoe [KM]) powders on the growth performance, carcass characteristics, serum cholesterol, and meat quality of broilers. Arbor Acres male broiler chicks (240) were fed diets supplemented with 0% (control), 0.5%, and 1% S. chinensis, or 0.5% and 1% KM in a completely randomized design. There were no differences among the groups with respect to growth performance or carcass weight and carcass ratio, but there were differences in mortality and relative weights of organs (liver, spleen, and abdominal fat). Diets supplemented with S. chinensis or KM led to reductions in total cholesterol (TC), low-density lipoprotein cholesterol (LDLC), and triglyceride levels and an increase in high-density lipoprotein cholesterol (HDLC) level. However, the S. chinensis and KM supplements produced no significant differences in proximate composition. Higher levels of S. chinensis and KM supplementation led to significantly better lipid oxidation stability and chicken thigh-meat quality (color), but there was no effect on pH and b*(yellowness). Moreover, the addition of KM had greater antioxidant and immune system effects than those of S. chinensis. In conclusion, diets with a 1% KM supplement had the greatest effect on reducing mortality and serum cholesterol levels, and increasing the meat quality of broilers.

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.