Schisandrin B inhibits inflammation and ferroptosis in S.aureus-induced mastitis through regulating SIRT1/p53/SLC7A11 signaling pathway.

Mastitis, one of the most significant problems in women, is commonly caused by pathogens, especially Staphylococcus aureus (S.aureus). Schisandrin B (SCB), the main abundant derivatives from Schisandra chinensis, has been proven to have the ability to inhibiting inflammation and bacteria. However, few relevant researches systematically illustrate the role SCB in the treatment of mastitis. The aim of the present study is to demonstrate the mechanism that SCB functions in reducing pathological injury to the mammary gland in treating S.aureus-induced mastitis. H&E staining was used to identify pathological changes and injuries in mastitis. The levels of cytokines associated with inflammation were detected by ELISA. Key signals relevant to ferroptosis and Nrf2 signaling pathway were tested by western blot analysis and iron assay kit. Compared with the control group, inflammation-associated factors, such as IL-1ß, TNF-α, MPO activity, increased significantly in S. aureus-treated mice. However, these changes were inhibited by SCB. Ferroptosis-associated factors Fe2+ and MDA increased significantly, and GSH, GPX4 and ferritin expression decreased markedly in S. aureus-treated mice. SCB treatment could attenuate S.aureus-induced ferroptosis. Furthermore, SCB increase SIRT1 and SLC7A11 expression and down-regulated p53 expression and NF-κB activation. In conclusion, SCB alleviates S.aureus-induced mastitis via up-regulating SIRT1/p53/SLC7A11 signaling pathway, attenuating the activation of inflammation-associated cytokines and ferroptosis in the mammary gland tissues.

Schisandrin B protect inner hair cells from cisplatin by inhibiting celluar oxidative stress and apoptosis.

Cisplatin is an effective chemotherapeutic agent; however, ototoxicity is one of its negative effects that greatly limits the use of cisplatin in clinical settings. Previous research has shown that the most important process cisplatin damage to inner ear cells, such as hair cells (HCs), is the excessive production and accumulation of ROS. Schisandrin B (SchB), is a low-toxicity, inexpensive, naturally occurring antioxidant with a variety of pharmacological effects. Therefore, the potential antioxidant effects of SchB may be useful for cisplatin ototoxicity treatment. In this study, the effects of SchB on cochlear hair cell viability, ROS levels, and expression of apoptosis-related molecules were evaluated by CCK-8, immunofluorescence, flow cytometry, and qRT-PCR, as well as auditory brainstem response (ABR) and dysmorphic product otoacoustic emission (DPOAE) tests to assess the effects on inner ear function. The results showed that SchB treatment increased cell survival, prevented apoptosis, and reduced cisplatin-induced ROS formation. SchB treatment reduced the loss of cochlear HCs caused by cisplatin in exosome culture. In addition, SchB treatment attenuated cisplatin-induced hearing loss and HC loss in mice. This study demonstrates the ability of SchB to inhibit cochlear hair cell apoptosis and ROS generation and shows its potential therapeutic effect on cisplatin ototoxicity.

Effects of schisandrin B on hypoxia-related cognitive function and protein expression in vascular dementia rats.

Vascular dementia (VD) a heterogenous group of brain disorders in which cognitive impairment is attributable to vascular risk factors and cerebrovascular disease. A common phenomenon in VD is a dysfunctional cerebral regulatory mechanism associated with insufficient cerebral blood flow, ischemia and hypoxia. Under hypoxic conditions oxygen supply to the brain results in neuronal death leading to neurodegenerative diseases including Alzheimer's (AD) and VD. In conditions of hypoxia and low oxygen perfusion, expression of hypoxia-inducible factor 1 alpha (HIF-1α) increases under conditions of low oxygen and low perfusion associated with upregulation of expression of hypoxia-upregulated mitochondrial movement regulator (HUMMR), which promotes anterograde mitochondrial transport by binding with trafficking protein kinesin 2 (TRAK2). Schisandrin B (Sch B) an active component derived from Chinese herb Wuweizi prevented ß-amyloid protein induced morphological alterations and cell death using a SH-SY5Y neuronal cells considered an AD model. It was thus of interest to determine whether Sch B might also alleviate VD using a rat bilateral common carotid artery occlusion (BCAO) dementia model. The aim of this study was to examine the effects of Sch B in BCAO on cognitive functions such as Morris water maze test and underlying mechanisms involving expression of HIF-1α, TRAK2, and HUMMR levels. The results showed that Sch B improved learning and memory function of rats with VD and exerted a protective effect on the hippocampus by inhibition of protein expression of HIF-1α, TRAK2, and HUMMR factors. Evidence indicates that Sch B may be considered as an alternative in VD treatment.

Schisandrin B from Schisandra chinensis alleviated pain via glycine receptors, Nav1.7 channels and Cav2.2 channels.

ETHNOPHARMACOLOGICAL RELEVANCE: Schisandra chinensis, the dried and ripe fruit of the magnolia family plant Schisandra chinensis (Turcz.) Baill, was commonly used in traditional analgesic prescription. Studies have shown that the extract of Schisandra chinensis (SC) displayed analgesic activity. However, the analgesic active component and the exact mechanisms have yet to be revealed. AIM OF THE STUDY: The present study was to investigate the anti-nociceptive constituent of Schisandra chinensis, assess its analgesic effect, and explore the potential molecular mechanisms. MATERIALS AND METHODS: The effects of a series of well-recognized compounds from SC on glycine receptors were investigated. The analgesic effect of the identified compound was evaluated in three pain models. Mechanistic studies were performed using patch clamp technique on various targets expressed in recombinant cells. These targets included glycine receptors, Nav1.7 sodium channels, Cav2.2 calcium channels et al. Meanwhile, primary cultured spinal dorsal horn (SDH) neurons and dorsal root ganglion (DRG) neurons were also utilized. RESULTS: Schisandrin B (SchB) was a positive allosteric modulator of glycine receptors in spinal dorsal horn neurons. The EC50 of SchB on glycine receptors in spinal dorsal horn neurons was 2.94 ± 0.28 µM. In three pain models, the analgesic effect of SchB was comparable to that of indomethacin at the same dose. Besides, SchB rescued PGE2-induced suppression of α3 GlyR activity and alleviated persistent pain. Notably, SchB could also potently decrease the frequency of action potentials and inhibit sodium and calcium channels in DRG neurons. Consistent with the data from DRG neurons, SchB was also found to significantly block Nav1.7 sodium channels and Cav2.2 channels in recombinant cells. CONCLUSION: Our results demonstrated that, Schisandrin B, the primary lignan component of Schisandra chinensis, may exert its analgesic effect by acting on multiple ion channels, including glycine receptors, Nav1.7 channels, and Cav2.2 channels.

Schisandrin B ameliorates adjuvant-induced arthritis in rats via modulation of inflammatory mediators, oxidative stress, and HIF-1α/VEGF pathway.

OBJECTIVES: Schisandrin B (Sch B) has been shown to possess anti-inflammatory and antioxidant properties, however, its antirheumatoid arthritis properties and potential mechanism remain unexplored. This study evaluated the potential of Sch B in adjuvant-induced arthritic (AIA) rats. METHODS: AIA was induced by injecting 0.1 ml of CFA into the paw of rats and the animals were administered with Sch B (50 mg/kg) for 28 days. The effects of Sch B were evaluated using arthritis severity, serum levels of oxido-inflammatory, and metabolic index parameters. KEY FINDINGS: Sch B eased arthritic symptoms by significantly reducing paw swelling and arthritic score and increased body weight gain. Moreover, Sch B alleviated the levels of oxido-inflammatory markers including interleukin-1 beta, interleukin-6, tumor necrosis factor alpha, nuclear factor kappa B, transforming growth factor ß1, inducible nitric oxide synthase and malonaldehyde, as well as increased the levels of superoxide dismutase, glutathione, and Nrf2. Sch B also remarkably restored the altered levels of triglyceride, aspartate aminotransferase, lactic acid, pyruvate, phosphoenolpyruvate carboxylase, glucose, hypoxia inducible factor-1 alpha, and vascular endothelial growth factor. In addition, Sch B markedly alleviated p65 expression in the treated AIA rats. CONCLUSION: This study suggests that Sch B alleviated AIA by reducing oxidative stress, inflammation, and angiogenesis.

Borneol-Modified Schisandrin B Micelles Cross the Blood-Brain Barrier To Treat Alzheimer's Disease in Aged Mice.

Objective: Schisandrin B (Sch B) is a bioactive dibenzocyclooctadiene derizative that is prevalent in the fruit of Schisandra chinensis. Numerous studies have demonstrated that Sch B has a neuroprotective action by reducing oxidative stress and effectively preventing inflammation. It follows that Sch B is a potential treatment for Alzheimer's disease (AD). However, the drug's solubility, bioavailability, and lower permeability of the blood-brain barrier (BBB) can all reduce its efficacy during the therapy process. Therefore, this study constructed borneol-modified schisandrin B micelles (Bor-Sch B-Ms), which increase brain targeting by accurately delivering medications to the brain, effectively improving bioavailability. High therapeutic efficacy has been achieved at the pathological site. Methods: Bor-Sch B-Ms were prepared using the thin film dispersion approach in this article. On the one hand, to observe the targeting effect of borneol, we constructed a blood-brain barrier (BBB) model in vitro and studied the ability of micelles to cross the BBB. On the other hand, the distribution of micelle drugs and their related pharmacological effects on neuroinflammation, oxidative stress, and neuronal damage were studied through in vivo administration in mice. Results: In vitro studies have demonstrated that the drug uptake of bEnd.3 cells was increased by the borneol alteration on the surface of the nano micelles, implying that Bor-Sch B-Ms can promote the therapeutic effect of N2a cells. This could result in more medicines entering the BBB. In addition, in vivo studies revealed that the distribution and circulation time of medications in the brain tissue were significantly higher than those in other groups, making it more suitable for the treatment of central nervous system diseases. Conclusion: As a novel nanodrug delivery system, borneol modified schisandrin B micelles have promising research prospects in the treatment of Alzheimer's disease.

The Use of Schisandrin B to Combat Triple-Negative Breast Cancers by Inhibiting NLRP3-Induced Interleukin-1ß Production.

Triple-negative breast cancer (TNBC) is the most aggressive and fatal breast cancer subtype. Nowadays, chemotherapy remains the standard treatment of TNBC, and immunotherapy has emerged as an important alternative. However, the high rate of TNBC recurrence suggests that new treatment is desperately needed. Schisandrin B (Sch B) has recently revealed its anti-tumor effects in cancers such as cholangiocarcinoma, hepatoma, glioma, and multi-drug-resistant breast cancer. However, there is still a need to investigate using Sch B in TNBC treatment. Interleukin (IL)-1ß, an inflammatory cytokine that can be expressed and produced by the cancer cell itself, has been suggested to promote BC proliferation and progression. In the current study, we present evidence that Sch B can significantly suppress the growth, migration, and invasion of TNBC cell lines and patient-derived TNBC cells. Through inhibition of inflammasome activation, Sch B inhibits interleukin (IL)-1ß production of TNBC cells, hindering its progression. This was confirmed using an NLRP3 inhibitor, OLT1177, which revealed a similar beneficial effect in combating TNBC progression. Sch B treatment also inhibits IL-1ß-induced EMT expression of TNBC cells, which may contribute to the anti-tumor response.

Schisandrin B, a dual positive allosteric modulator of GABAA and glycine receptors, alleviates seizures in multiple mouse models.

Epilepsy is a prevalent and severe neurological disorder and approximately 30% of patients are resistant to existing medications. It is of utmost importance to develop alternative therapies to treat epilepsy. Schisandrin B (SchB) is a major bioactive constituent of Schisandra chinensis (Turcz.) Baill and has multiple neuroprotective effects, sedative and hypnotic activities. In this study, we investigated the antiseizure effect of SchB in various mouse models of seizure and explored the underlying mechanisms. Pentylenetetrazole (PTZ), strychnine (STR), and pilocarpine-induced mouse seizure models were established. We showed that injection of SchB (10, 30, 60 mg/kg, i.p.) dose-dependently delayed the onset of generalized tonic-clonic seizures (GTCS), reduced the incidence of GTCS and mortality in PTZ and STR models. Meanwhile, injection of SchB (30 mg/kg, i.p.) exhibited therapeutic potential in pilocarpine-induced status epilepticus model, which was considered as a drug-resistant model. In whole-cell recording from CHO/HEK-239 cells stably expressing recombinant human GABAA receptors (GABAARs) and glycine receptors (GlyRs) and cultured hippocampal neurons, co-application of SchB dose-dependently enhanced GABA or glycine-induced current with EC50 values at around 5 µM, and application of SchB (10 µM) alone did not activate the channels in the absence of GABA or glycine. Furthermore, SchB (10 µM) eliminated both PTZ-induced inhibition on GABA-induced current (IGABA) and strychnine (STR)-induced inhibition on glycine-induced current (Iglycine). Moreover, SchB (10 µM) efficiently rescued the impaired GABAARs associated with genetic epilepsies. In addition, the homologous mutants in both GlyRs-α1(S267Q) and GABAARs-α1(S297Q)ß2(N289S)γ2L receptors by site-directed mutagenesis tests abolished SchB-induced potentiation of IGABA and Iglycine. In conclusion, we have identified SchB as a natural positive allosteric modulator of GABAARs and GlyRs, supporting its potential as alternative therapies for epilepsy.

Inhibition of autophagy enhances the anticancer effect of Schisandrin B on head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is among the most common malignant tumors worldwide and has a poor prognosis. Autophagy regulation has been proposed as a possible treatment option for HNSCC. Schisandrin B (Sch B) exerts anticancer effects by regulating apoptosis and autophagy, but the anticancer effect of Sch B in HNSCC remains unclear. This study aimed to investigate the effects of Sch B on human Cal27 HNSCC cells and to further reveal its potential regulatory mechanisms. The anticancer effect of Sch B was evaluated in vitro by flow cytometry, clonogenic assays, and Western blot analysis. The regulatory mechanism of Sch B-induced apoptosis and autophagy was further explored by polymerase chain reaction, luciferase assay, and reactive oxygen species (ROS) detection. The results showed that Sch B significantly induced apoptosis and autophagy in Cal27 cells and that inhibition of autophagy enhanced the apoptotic effect of Sch B on Cal27 cells. Additionally, Sch B-activated autophagy in Cal27 cells was dependent on the nuclear factor-kappa B (NF-κB) pathway, and ROS acted as a regulator of the NF-B pathway. N-acetylcysteine, a scavenger of ROS, inhibited Sch B-dependent autophagy via the NF-κB pathway. Based on the results, Sch B is a potential therapeutic agent for HNSCC and activates the NF-κB pathway by increasing ROS production, which subsequently promotes autophagy in HNSCC cells. Therefore, the strategy of enhancing the anticancer effect of Sch B by inhibiting autophagy deserves further attention.

Schisandrin B Alleviates Renal Tubular Cell Epithelial-Mesenchymal Transition and Mitochondrial Dysfunction by Kielin/Chordin-like Protein Upregulation via Akt Pathway Inactivation and Adenosine 5'-Monophosphate (AMP)-Activated Protein Kinase Pathway Activation in Diabetic Kidney Disease.

Diabetic kidney disease is a common complication of diabetes and remains the primary cause of end-stage kidney disease in the general population. Schisandrin B (Sch B) is an active ingredient in Schisandra chinensis. Our study illustrates that Sch B can mitigate renal tubular cell (RTC) epithelial-mesenchymal transition (EMT) and mitochondrial dysfunction in db/db mice, accompanied by the downregulation of TGF-ß1 and the upregulation of PGC-1α. Similarly, Sch B demonstrated a protective effect by reducing the expression of TGF-ß1, α-SMA, fibronectin, and Col I, meanwhile enhancing the expression of E-cadherin in human RTCs (HK2 cells) stimulated with high glucose. Moreover, under high glucose conditions, Sch B effectively increased mitochondrial membrane potential, lowered ROS production, and increased the ATP content in HK2 cells, accompanied by the upregulation of PGC-1α, TFAM, MFN1, and MFN2. Mechanistically, the RNA-seq results showed a significant increase in KCP mRNA levels in HK2 cells treated with Sch B in a high glucose culture. The influence of Sch B on KCP mRNA levels was confirmed by real-time PCR in high glucose-treated HK2 cells. Depletion of the KCP gene reversed the impact of Sch B on TGF-ß1 and PGC-1α in HK2 cells with high glucose level exposure, whereas overexpression of the KCP gene blocked EMT and mitochondrial dysfunction. Furthermore, the PI3K/Akt pathway was inhibited and the AMPK pathway was activated in HK2 cells exposed to a high concentration of glucose after the Sch B treatment. Treatment with the PI3K/Akt pathway agonist insulin and the AMPK pathway antagonist compound C attenuated the Sch B-induced KCP expression in HK2 cells exposed to a high level of glucose. Finally, molecular autodock experiments illustrated that Sch B could bind to Akt and AMPK. In summary, our findings suggested that Sch B could alleviate RTC EMT and mitochondrial dysfunction by upregulating KCP via inhibiting the Akt pathway and activating the AMPK pathway in DKD.

Schisandrin B Promotes Hepatic Stellate Cell Ferroptosis via Wnt Pathway-Mediated Ly6Clo Macrophages.

A key event in liver fibrosis is the activation of the hepatic stellate cell (HSC). Schisandrin B (Sch B), a major component extracted from Schisandra chinensis, has been shown to inhibit HSC activation. Recently, ferroptosis (FPT) has been reported to be involved in HSC activation. However, whether Sch B has an effect on the HSC FPT remains unclear. Herein, we explored the effects of Sch B on liver fibrosis in vivo and in vitro and the roles of Wnt agonist 1 and ferrostatin-1 in the antifibrotic effects of Sch B. Sch B effectively alleviated CCl4-induced liver fibrosis, with decreased collagen deposition and α-SMA level. Additionally, Sch B resulted in an increase in lymphocyte antigen 6 complex locus C low (Ly6Clo) macrophages, contributing to a reduced level of TIMP1 and increased MMP2. Notably, the Wnt pathway was involved in Sch B-mediated Ly6C macrophage phenotypic transformation. Further studies demonstrated that Sch B-treated macrophages had an inhibitory effect on HSC activation, which was associated with HSC FPT. GPX4, a negative regulator of FPT, was induced by Sch B and found to be involved in the crosstalk between macrophage and HSC FPT. Furthermore, HSC inactivation as well as FPT induced by Sch B-treated macrophages was blocked down by Wnt pathway agonist 1. Collectively, we demonstrate that Sch B inhibits liver fibrosis, at least partially, through mediating Ly6Clo macrophages and HSC FPT. Sch B enhances Wnt pathway inactivation, leading to the increase in Ly6Clo macrophages, which contributes to HSC FPT. Sch B may be a promising drug for liver fibrosis treatment.

Involvement of PI3K/Akt/ß-catenin signaling in schisandrin B-mitigated bone deterioration in an experimental rat model of estrogen deficiency.

Introduction: Schisandrin B (SchB) has been reported to perform a wide range of biological functions, including antioxidant activity, anti-inflammatory activity and stimulation of osteoblast proliferation. However, the function and mechanism of SchB in ovariectomy (OVX)-induced osteoporosis are still unknown. The present study was designed to investigate the anti-osteoporotic activity of SchB in an experimental rat model of estrogen deficiency, which is usually used to mimic human postmenopausal osteoporosis (PMO). Material and methods: OVX rats were orally treated with low (10 mg/kg) or high (50 mg/kg) doses of SchB for 8 weeks. Bone metabolism-related markers were measured by ELISA. The levels of protein expression were determined by western blotting analysis. Hematoxylin and eosin (H&E) and safranin O staining were performed to analyze trabecular bone and cartilage degeneration. Tartrate-resistant acid phosphatase (TRAP) staining was used to evaluate osteoclast differentiation. Results: SchB administration markedly increased serum Ca levels and bone Ca content and decreased urinary calcium excretion in OVX-operated rats. In addition, high-dosage SchB treatment blocked osteoclastogenesis and improved trabecular bone and cartilage degeneration in the tibia of OVX-operated rats. Furthermore, high-dosage SchB treatment dramatically elevated the protein expression of phospho-PI3K, phospho-Akt and ß-catenin in OVX-operated rats. Conclusions: SchB exerted anti-osteoporotic activity in OVX-operated rats by accelerating the phosphorylation of PI3K and Akt, subsequently upregulating the expression of ß-catenin.

Schisandrin B Inhibits Cell Viability and Malignant Progression of Melanoma Cells via Wnt/ß-catenin Signaling Pathway.

BACKGROUND: Melanoma is of great interest due to its aggressive behavior and less favorable prognosis. The need for the development of novel drugs for the treatment of melanoma is urgent. Considerable evidence indicated that Schisandrin B (Sch B), a bioactive compound extracted from Schisandra chinensis, has numerous anti-tumor properties in multiple malignant tumors. A few studies have reported the effect of Sch B on melanogenesis in the melanoma B16F10 cell line; however, the specific anti-tumor effects and mechanisms need to be further explored. OBJECTIVE: This study aimed to investigate the effects of Sch B on the cell viability, migration, invasion, and cell cycleblocking of melanoma cells and explore its potential anti-tumor mechanism in vitro and in vivo. METHODS: Melanoma cells (A375 and B16) were treated with different concentrations of Sch B (0, 20, 40, 60, or 80 µM), with dimethyl sulfoxide (DMSO) as control. The inhibitory effect of Sch B on A375 and B16 melanoma cells was verified by crystal violet assay and CCK8 assay. The flow cytometry was performed to observe cell cycle blocking. The effect of Sch B on the migration and invasion of melanoma cells was detected by wound healing assay and transwell assay, respectively. Western blot analysis was used to determine protein expression levels. The growth of the A375 melanoma xenograft-treated groups and immunohistochemical staining were conducted to assess the anti-tumor effect of Sch B in vivo. RESULTS: The crystal violet assay and CCK8 assay showed that Sch B significantly inhibited melanoma cell viability in a dose-dependent manner. Meanwhile, the flow cytometry analysis revealed that Sch B induced melanoma cell cycleblocking at the G1/S phase. In addition, the wound healing assay and transwell assay showed that Sch B inhibited the migration and invasion of melanoma cells. Furthermore, by establishing an animal model, we found that Sch B significantly inhibited the growth of melanoma in vivo. The potential mechanism could be that Sch B inhibited the activity of the Wnt/ß-catenin signaling pathway. CONCLUSION: These findings indicated that Sch B inhibits the cell viability and malignant progression of melanoma cells via the Wnt/ß-catenin pathway and induces cell cycle arrest. Our study suggests that Sch B has potential as a bioactive compound for the development of new drugs for melanoma.

In Silico Analysis, Anticonvulsant Activity, and Toxicity Evaluation of Schisandrin B in Zebrafish Larvae and Mice.

The aim of this study is to evaluate the anticonvulsant potential of schisandrin B, a main ingredient of Schisandra chinensis extracts. Schisandrin B showed anticonvulsant activity in the zebrafish larva pentylenetetrazole acute seizure assay but did not alter seizure thresholds in the intravenous pentylenetetrazole test in mice. Schisandrin B crosses the blood-brain barrier, which we confirmed in our in silico and in vivo analyses; however, the low level of its unbound fraction in the mouse brain tissue may explain the observed lack of anticonvulsant activity. Molecular docking revealed that the anticonvulsant activity of the compound in larval zebrafish might have been due to its binding to a benzodiazepine site within the GABAA receptor and/or the inhibition of the glutamate NMDA receptor. Although schisandrin B showed a beneficial anticonvulsant effect, toxicological studies revealed that it caused serious developmental impairment in zebrafish larvae, underscoring its teratogenic properties. Further detailed studies are needed to precisely identify the properties, pharmacological effects, and safety of schisandrin B.

Schisandrin B, a potential GLP-1R agonist, exerts anti-diabetic effects by stimulating insulin secretion.

Diabetes mellitus is a metabolic disease that is characterized by elevated blood sugar. Although glucagon-like peptide-1 receptor agonists (GLP-1RA) lower blood glucose in a glucose-dependent manner, most of them are macromolecule polypeptides. Macromolecular peptides are relatively expensive and inconvenient compared with small molecules. Therefore, this study sought to identify the small molecules binding to GLP-1R via cell membrane chromatography (CMC), confirm their agonistic activity, and further study its beneficial effects in a mouse model of type 2 diabetes mellitus (T2DM) induced by a combination of high-fat diet and streptozotocin. We used CMC, calcium imaging and molecular docking techniques to screen and identify the potential small molecule Schisandrin B (Sch B), which exhibits a strong binding effect to GLP-1R, from the small molecule library of traditional Chinese medicine. Through in-vitro experiments, we found that Sch B stimulated insulin secretion in ß-TC-6 cells, while GLP-1R antagonist Exendin9-39, adenylate cyclase inhibitor SQ22536, and protein kinase A (PKA) inhibitor H89 could significantly inhibit the insulin secretion induced by Sch B. In vivo, Sch B significantly improved fasting blood glucose levels, intraperitoneal glucose tolerance test damage, and the status of pancreatic tissue damage, and reduced serum insulin levels, total cholesterol, triglyceride and low density lipoprotein in T2DM mice. These results indicate that Sch B alleviates T2DM by promoting insulin release through the GLP-1R/cAMP/PKA signaling pathway, suggesting that Sch B may be a potential GLP-1RA, which is expected to provide a new therapeutic strategy for the prevention and treatment of T2DM.

Scavenger receptor A-mediated nanoparticles target M1 macrophages for acute liver injury.

Acute liver injury (ALI) has an elevated fatality rate due to untimely and ineffective treatment. Although, schisandrin B (SchB) has been extensively used to treat diverse liver diseases, its therapeutic efficacy on ALI was limited due to its high hydrophobicity. Palmitic acid-modified serum albumin (PSA) is not only an effective carrier for hydrophobic drugs, but also has a superb targeting effect via scavenger receptor-A (SR-A) on the M1 macrophages, which are potential therapeutic targets for ALI. Compared with the common macrophage-targeted delivery systems, PSA enables site-specific drug delivery to reduce off-target toxicity. Herein, we prepared SchB-PSA nanoparticles and further assessed their therapeutic effect on ALI. In vitro, compared with human serum albumin encapsulated SchB nanoparticles (SchB-HSA NPs), the SchB-PSA NPs exhibited more potent cytotoxicity on lipopolysaccharide (LPS) stimulated Raw264.7 (LAR) cells, and LAR cells took up PSA NPs 8.79 times more than HSA NPs. As expected, the PSA NPs also accumulated more in the liver. Moreover, SchB-PSA NPs dramatically reduced the activation of NF-κB signaling, and significantly relieved inflammatory response and hepatic necrosis. Notably, the high dose of SchB-PSA NPs improved the survival rate in 72 h of ALI mice to 75%. Hence, SchB-PSA NPs are promising to treat ALI.

Schisandrin B Protects against Ischemic Brain Damage by Regulating PI3K/AKT Signaling in Rats.

OBJECTIVE: To explore the effect and mechanism of schisandrin B (Sch B) in the treatment of cerebral ischemia in rats. METHODS: The cerebral ischemia models were induced by middle cerebral artery occlusion (MCAO) and reperfusion. Sprague-Dawley rats were divided into 6 groups using a random number table, including sham, MCAO, MCAO+Sch B (50 mg/kg), MCAO+Sch B (100 mg/kg), MCAO+Sch B (100 mg/kg)+LY294002, and MCAO+Sch B (100 mg/kg)+wortmannin groups. The effects of Sch B on pathological indicators, including neurological deficit scores, cerebral infarct volume, and brain edema, were subsequently studied. Tissue apoptosis was identified by terminal transferase-mediated dUTP nick end-labeling (TUNEL) staining. The protein expressions involved in apoptosis, inflammation response and oxidative stress were examined by immunofluorescent staining, biochemical analysis and Western blot analysis, respectively. The effect of Sch B on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling was also explored. RESULTS: Sch B treatment decreased neurological deficit scores, cerebral water content, and infarct volume in MCAO rats (P<0.05 or P<0.01). Neuronal nuclei and TUNEL staining indicated that Sch B also reduced apoptosis in brain tissues, as well as the Bax/Bcl-2 ratio and caspase-3 expression (P<0.01). Sch B regulated the production of myeloperoxidase, malondialdehyde, nitric oxide and superoxide dismutase, as well as the release of cytokine interleukin (IL)-1 ß and IL-18, in MCAO rats (P<0.05 or P<0.01). Sch B promoted the phosphorylation of PI3K and AKT. Blocking the PI3K/AKT signaling pathway with LY294002 or wortmannin reduced the protective effect of Sch B against cerebral ischemia (P<0.05 or P<0.01). CONCLUSIONS: Sch B reduced apoptosis, inflammatory response, and oxidative stress of MCAO rats by modulating the PI3K/AKT pathway. Sch B had a potential for treating cerebral ischemia.

Schisandrin B induces HepG2 cells pyroptosis by activating NK cells mediated anti-tumor immunity.

Pyroptosis, an inflammatory programmed cell death, has been suggested as a novel molecular mechanism for the treatment of hepatocellular carcinoma (HCC) with chemotherapeutic agents. Recent studies showed that natural killer (NK) cells could inhibit apoptosis and regulate the progression of pyroptosis in tumor cells. Schisandrin B (Sch B), a lignan isolated from Schisandrae chinensis (Turcz.) Baill. (Schisandraceae) Fructus, has various pharmacological activities including anti-cancer effects. The purpose of this study was to investigate the effect of NK cells on Sch B's regulation of pyroptosis in HCC cells and the molecular mechanisms implicated. The results showed that Sch B alone could decrease cell viability and induce apoptosis in HepG2 cells. However, Sch B induced apoptosis in HepG2 cells was transformed into pyroptosis in the presence of NK cells. The mechanisms underlying NK cell's effect on pyroptosis in Sch B-treated HepG2 cells was related to its activation of caspase 3-Gasdermin E (GSDME). Further studies revealed that NK cell induced caspase 3 activation was derived from its activation of perforin-granzyme B pathway. This study explored the effect of Sch B and NK cells on pyroptosis in HepG2 cells and revealed that perforin-granzyme B-caspase 3-GSDME pathway is involved in the process of pyroptosis. These results proposed an immunomodulatory mechanism of Sch B on HepG2 cells pyroptosis and suggested Sch B as a promising immunotherapy combination partner for the treatment of HCC.

Quantitative proteomics combined with network pharmacology analysis unveils the biological basis of Schisandrin B in treating diabetic nephropathy.

BACKGROUND: Diabetic nephropathy (DN) is a major complication of diabetes. Schisandrin B (Sch) is a natural pharmaceutical monomer that was shown to prevent kidney damage caused by diabetes and restore its function. However, there is still a lack of comprehensive and systematic understanding of the mechanism of Sch treatment in DN. OBJECTIVE: We aim to provide a systematic overview of the mechanisms of Sch in multiple pathways to treat DN in rats. METHODS: Streptozocin was used to build a DN rat model, which was further treated with Sch. The possible mechanism of Sch protective effects against DN was predicted using network pharmacology and was verified by quantitative proteomics analysis. RESULTS: High dose Sch treatment significantly downregulated fasting blood glucose, creatinine, blood urea nitrogen, and urinary protein levels and reduced collagen deposition in the glomeruli and tubule-interstitium of DN rats. The activities of superoxide dismutase (SOD) and plasma glutathione peroxidase (GSH-Px) in the kidney of DN rats significantly increased with Sch treatment. In addition, the levels of IL-6, IL-1ß, and TNF-α were significantly reduced in DN rats treated with Sch. 11 proteins that target both Sch and DN were enriched in pathways such as MAPK signaling, PI3K-Akt signaling, renal cell carcinoma, gap junction, endocrine resistance, and TNF signaling. Furthermore, quantitative proteomics showed that Xaf1 was downregulated in the model vs. control group and upregulated in the Sch-treated vs. model group. Five proteins, Crb3, Tspan4, Wdr45, Zfp512, and Tmigd1, were found to be upregulated in the model vs. control group and downregulated in the Sch vs. model group. Three intersected proteins between the network pharmacology prediction and proteomics results, Crb3, Xaf1, and Tspan4, were identified. CONCLUSION: Sch functions by relieving oxidative stress and the inflammatory response by regulating Crb3, Xaf1, and Tspan4 protein expression levels to treat DN disease.

Schisandrin B inhibits tumor progression of hepatocellular carcinoma by targeting the RhoA/ROCK1 pathway.

Background: Schisandrin B (Sch. B) performs various pharmacological properties, including anticancer activities. However, the pharmacological mechanisms of Sch. B in hepatocellular carcinoma (HCC) are not fully elucidated. We investigated the impact and mechanism on progression in HCC, and to provide new experimental evidence for HCC treatment. Methods: To determine the inhibitory effect of Sch. B on HCC in vivo, 32 Balb/c nude mice were used to prepare the tumor-bearing mice model by subcutaneously inoculating HCC cells (Huh-7). As tumor volume grew to 100 mm3, mice were randomly divided into Saline (control group), 100 mg/kg Sch. B group (Sch. B-L), 200 mg/kg Sch. B group (Sch. B-M), and 400 mg/kg Sch. B group (Sch. B-H) (n=8). Saline or different concentration Sch. B was used to treat mice via gavage administration for 21 days. After mice were euthanized, tumor weight and volume were evaluated. Cell apoptosis was detected by TUNEL. Ki-67 and PCNA were detected by immunohistochemical staining. The RhoA and Rho-associated protein kinase 1 (ROCK1) were determined by western blot. In vitro experiment, Huh-7 cell were treated by Sch. B at 40, 30, 20, 10, 5, 1, and 0 µM to detect cell proliferation by Cell Counting Kit-8 (CCK-8). Huh-7 cells were divided as a control group, Sch. B group, and Sch. B + RhoA overexpression (Sch. B + RhoA) group. RhoA and ROCK1 were examined. The colony formation assay and flow cytometry were used to detect cell proliferation and apoptosis. The wound healing and Transwell assays were used for cell metastasis detection. Results: Our results showed 100, 200 and 400 mg/kg Sch. B significantly reduced tumor weight and volume. And 200 and 400 mg/kg Sch. B increased apoptosis, and reduced Ki-67 and PCNA levels, inhibited the RhoA and ROCK1 in vivo (P<0.05). In vitro experiment, Sch. B inhibited Huh-7 cell proliferation at concentration more than 10 µM (P<0.05). Sch. B decreased cell duplication, promoted apoptosis and blocked migration and invasion of Huh-7 (P<0.05). Sch. B inhibited RhoA and ROCK1 level as compared with control group (P<0.05). RhoA overexpression reversed the effect of Sch. B (P<0.05). Conclusions: Sch. B inhibits Huh-7 cells progression via RhoA/ROCK1 pathway. The results provide new evidence for the clinical treatment of HCC.