Baicalein alleviates intrahepatic cholestasis by regulating bile acid metabolism via an FXR-dependent manner.

Cholestasis is characterized by impaired bile secretion and flow, leading to the accumulation of toxic bile acids in the liver, further causing inflammatory reaction, fibrosis, and ultimately liver transplantation. Although first-line clinical agents such as Ursodeoxycholic acid (UDCA) and Obeticholic acid (OCA) are available, serious side effects still exist. Therefore, pharmacologic treatment of cholestatic liver disease remains challenging. Here, we used a murine model of cholestasis treated with or without intraperitoneal injection of baicalein and found that baicalein could attenuate 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet-induced inflammatory response, ductular reaction, liver fibrosis, and bile acid metabolism disorders. Furthermore, the therapeutic effect of baicalein was hampered in the presence of Guggulsterone (GS), an Farnesoid X receptor (FXR) antagonist. These results indicated that baicalein alleviated DDC diet-induced cholestatic liver injury in an FXR-dependent manner.

Baicalein promotes KDM4E to induce BICD1 and inhibit triple-negative breast cancer progression by blocking PAR1 signaling.

Baicalein has been implicated in the chemotherapy overcoming triple-negative breast cancer (TNBC). However, many unanswered questions remain regarding its role in treating TNBC. Here, we sought to demonstrate the molecular pathway mediated by baicalein in TNBC. Lysine-specific demethylase 4E (KDM4E), reduced in TNBC cells, was identified as a target protein of baicalein, and baicalein enhanced the protein expression and stability of KDM4E in TNBC cells. Knockdown of KDM4E attenuated the inhibitory effect of baicalein on TNBC cell activity, as demonstrated by intensified mobility, viability, and apoptosis resistance in TNBC cells. KDM4E activated protein bicaudal D homolog 1 (BICD1) expression by reducing the deposition of histone H3 lysine 9 trimethylation (H3K9me3) in its promoter, whereas BICD1 promoted protease-activated receptor-1 (PAR1) endocytosis and blocked PAR1 signaling through physical interaction with PAR1. Knockdown of KDM4E strengthened the PAR1-dependent activity of TNBC cells in response to thrombin activation, whereas TNBC progression activated by PAR1 signaling was blocked by combined overexpression of BICD1. Taken together, our data indicate that baicalein-promoted KDM4E enhanced the expression of BICD1 and activated the inhibitory effect of BICD1 on PAR1 signaling, thereby inhibiting TNBC progression.

VEGF and EGFR signaling pathways are involved in the baicalein attenuation of OVA-induced airway inflammation and airway remodeling in mice.

BACKGROUND: Although Traditional Chinese Medicine (TCM) has been used for treating asthma for centuries, the understanding of its mechanism of action is still limited. Thus, the purpose of this study was to explore the possible therapeutic effects, and underlying mechanism of baicalein in the treatment of asthma. METHODS: Freely availabled atabases (e.g. OMIM, TTD, Genecards, BATMAN-TCM, STITCH 5.0, SEA, SwissTargetPrediction) and software (e.g. Ligplot 2.2.5 and PyMoL) were used for disease drug target prediction and molecular docking by network pharmacology. The efficacy and mechanism of action of baicalein in the treatment of asthma were validated using an ovalbumin (OVA)-induced asthma mouse model and molecular biology techniques. RESULTS: A total of 1655 asthma-related genes and 161 baicalein-related targets were identified from public databases. Utilizing common databases and software for network pharmacology and molecular docking analysis, seven potential target proteins for the therapeutic effects of baicalein on asthma were selected, including v-akt murine thymoma viral oncogene homolog 1 (AKT1), vascular endothelial growth factor A (VEGFA), epidermal growth factor receptor (EGFR), proto-oncogene tyrosine-protein kinase Src (SRC), mitogen-activated protein kinase 3 (MAPK3), matrix metallopeptidase 9 (MMP9), and MAPK1. In vivo, baicalein treatment via intraperitoneal injection at a dose of 50 mg/kg significantly reduced airway inflammation, collagen deposition, smooth muscle thickness, lung interleukin (IL)-4 and IL-13 levels, peripheral blood immunoglobulin (Ig)E levels, as well as the count and ratio of eosinophils in bronchoalveolar lavage fluid (BALF) in an OVA-induced asthma mouse model. Further validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting analysis revealed that the VEGF and EGFR signaling pathways involving VEGFA, MAPK1, MAPK3, and EGFR were inhibited by baicalein in the asthma mouse model. CONCLUSION: Baicalein attenuates airway inflammation and airway remodeling through inhibition of VEGF and EGFR signaling pathways in an OVA-induced asthma mouse model. This will provide a new basis for the development of baicalein as a treatment for asthma and highlights the potential of network pharmacology and molecular docking in drug discovery and development.

Baicalin and baicalein in modulating tumor microenvironment for cancer treatment: A comprehensive review with future perspectives.

Cancer is a leading cause of death worldwide. The burden of cancer incidence and mortality is increasing rapidly. New approaches to cancer prevention and treatment are urgently needed. Natural products are reliable and powerful sources for anticancer drug discovery. Baicalin and baicalein, two major flavones isolated from Scutellaria baicalensis Georgi, a multi-purpose traditional medicinal plant in China, exhibit anticancer activities against multiple cancers. Of note, these phytochemicals exhibit extremely low toxicity to normal cells. Besides their cytotoxic and cytostatic activities toward diverse tumor cells, recent studies demonstrated that baicalin and baicalein modulate a variety of tumor stromal cells and extracellular matrix (ECM) in the tumor microenvironment (TME), which is essential for tumorigenesis, cancer progression and metastasis. In this review, we summarize the therapeutic potential and the mechanism of action of baicalin and baicalein in the regulation of tumor microenvironmental immune cells, endothelial cells, fibroblasts, and ECM that reshape the TME and cancer signaling, leading to inhibition of tumor angiogenesis, progression, and metastasis. In addition, we discuss the biotransformation pathways of baicalin and baicalein, related therapeutic challenges and the future research directions to improve their bioavailability and clinical anticancer applications. Recent advances of baicalin and baicalein warrant their continued study as important natural ways for cancer interception and therapy.

Baicalein attenuates oxidative damage in mice haematopoietic cells through regulation of PDGFRß.

Platelet-derived growth factor receptor ß (PDGFRß) plays a crucial role in murine haematopoiesis. Baicalein (BAI), a naturally occurring flavonoid, can alleviate disease damage through anti-oxidative, anti-apoptotic, and anti-inflammatory mechanisms. However, whether BAI attenuates oxidative damage in murine haematopoietic cells by PDGFRß remains unexplored. In this study, we utilized a tert-butyl hydroperoxide (TBHP)-induced BaF3 cell injury model and an ionising radiation (IR)-induced mice injury model to investigate the impact of the presence or absence of PDGFRß on the pharmacological effects of BAI. In addition, the BAI-PDGFRß interaction was characterized by molecular docking and dynamics simulations. The results show that a specific concentration of BAI led to increased cell viability, reduced reactive oxygen species (ROS) content, upregulated nuclear factor erythroid 2-related factor 2 (NRF2) expression, and its downstream target genes heme oxygenase 1 (HO-1) and NAD(P)H Quinone Dehydrogenase 1 (NQO1), and activated protein kinase B (AKT) pathway in cells expressing PDGFRß plasmid and experiencing damage. Similarly, BAI elevated lineage-Sca1+cKIT+ (LSK) cell proportion, promoted haematopoietic restoration, enhanced NRF2-mediated antioxidant response in PDGFRß+/+ mice. However, despite BAI usage, PDGFRß knockout mice (PDGFRß-/-) showed lower LSK proportion and less antioxidant capacity than the total body irradiation (TBI) group. Furthermore, we demonstrated an interaction between BAI and PDGFRß at the molecular level. Collectively, our results indicate that BAI attenuates oxidative stress injury and helps promote haematopoietic cell recovery through regulation of PDGFRß.

Hepatoprotective effects of baicalein against liver ischemia-reperfusion injury and partial hepatectomy in a rat model.

BACKGROUND: Baicalein is the main active flavonoid in Scutellariae Radix and is included in shosaikoto, a Kampo formula used for treating hepatitis and jaundice. However, little is known about its hepatoprotective effects against hepatic ischemia-reperfusion injury (HIRI), a severe clinical condition directly caused by interventional procedures. We aimed to investigate the hepatoprotective effects of baicalein against HIRI and partial hepatectomy (HIRI + PH) and its potential underlying mechanisms. METHODS AND RESULTS: Male Sprague-Dawley rats received either baicalein (5 mg/kg) or saline intraperitoneally and underwent a 70% hepatectomy 15 min after hepatic ischemia. After reperfusion, liver and blood samples were collected. Survival was monitored 30 min after hepatic ischemia and hepatectomy. In interleukin 1ß (IL-1ß)-treated primary cultured rat hepatocytes, the influence of baicalein on inflammatory mediator production and the associated signaling pathway was analyzed. Baicalein suppressed apoptosis and neutrophil infiltration, which are the features of HIRI + PH treatment-induced histological injury. Baicalein also reduced the mRNA expression of the proinflammatory cytokine tumor necrosis factor-α (TNF-α). In addition, HIRI + PH treatment induced liver enzyme deviations in the serum and hypertrophy of the remnant liver, which were suppressed by baicalein. In the lethal HIRI + PH treatment group, baicalein significantly reduced mortality. In IL-1ß-treated rat hepatocytes, baicalein suppressed TNF-α and chemokine mRNA expression as well as the activation of nuclear factor-kappa B (NF-κB) and Akt. CONCLUSIONS: Baicalein treatment attenuates HIRI + PH-induced liver injury and may promote survival. This potential hepatoprotection may be partly related to suppressing inflammatory gene induction through the inhibition of NF-κB activity and Akt signaling in hepatocytes.

Baicalein triggers ferroptosis in colorectal cancer cells via blocking the JAK2/STAT3/GPX4 axis.

Colorectal cancer (CRC) is a prevalent form of gastrointestinal malignancy with challenges in chemotherapy resistance and side effects. Effective and low toxic drugs for CRC treatment are urgently needed. Ferroptosis is a novel mode of cell death, which has garnered attention for its therapeutic potential against cancer. Baicalein (5, 6, 7-trihydroxyflavone) is the primary flavone extracted from the dried roots of Scutellaria baicalensis that exhibits anticancer effects against several malignancies including CRC. In this study, we investigated whether baicalein induced ferroptosis in CRC cells. We showed that baicalein (1-64 µM) dose-dependently inhibited the viability of human CRC lines HCT116 and DLD1. Co-treatment with the ferroptosis inhibitor liproxstatin-1 (1 µM) significantly mitigated baicalein-induced CRC cell death, whereas autophagy inhibitor chloroquine (25 µM), necroptosis inhibitor necrostatin-1 (10 µM), or pan-caspase inhibitor Z-VAD-FMK (10 µM) did not rescue baicalein-induced CRC cell death. RNA-seq analysis confirmed that the inhibitory effect of baicalein on CRC cells is associated with ferroptosis induction. We revealed that baicalein (7.5-30 µM) dose-dependently decreased the expression levels of GPX4, key regulator of ferroptosis, in HCT116 and DLD1 cells by blocking janus kinase 2 (JAK2)/STAT3 signaling pathway via direct interaction with JAK2, ultimately leading to ferroptosis in CRC cells. In a CRC xenograft mouse model, administration of baicalein (10, 20 mg/kg, i.g., every two days for two weeks) dose-dependently inhibited the tumor growth with significant ferroptosis induced by inhibiting the JAK2/STAT3/GPX4 axis in tumor tissue. This study demonstrates that ferroptosis contributes to baicalein-induced anti-CRC activity through blockade of the JAK2/STAT3/GPX4 signaling pathway, which provides evidence for the therapeutic application of baicalein against CRC.

Baicalein attenuates rotenone-induced SH-SY5Y cell apoptosis through binding to SUR1 and activating ATP-sensitive potassium channels.

Dopaminergic neurons in the substantia nigra (SN) expressing SUR1/Kir6.2 type ATP-sensitive potassium channels (K-ATP) are more vulnerable to rotenone or metabolic stress, which may be an important reason for the selective degeneration of neurons in Parkinson's disease (PD). Baicalein has shown neuroprotective effects in PD animal models. In this study, we investigated the effect of baicalein on K-ATP channels and the underlying mechanisms in rotenone-induced apoptosis of SH-SY5Y cells. K-ATP currents were recorded from SH-SY5Y cells using whole-cell voltage-clamp recording. Drugs dissolved in the external solution at the final concentration were directly pipetted onto the cells. We showed that rotenone and baicalein opened K-ATP channels and increased the current amplitudes with EC50 values of 0.438 µM and 6.159 µM, respectively. K-ATP channel blockers glibenclamide (50 µM) or 5-hydroxydecanoate (5-HD, 250 µM) attenuated the protective effects of baicalein in reducing reactive oxygen species (ROS) content and increasing mitochondrial membrane potential and ATP levels in rotenone-injured SH-SY5Y cells, suggesting that baicalein protected against the apoptosis of SH-SY5Y cells by regulating the effect of rotenone on opening K-ATP channels. Administration of baicalein (150, 300 mg·kg-1·d-1, i.g.) significantly inhibited rotenone-induced overexpression of SUR1 in SN and striatum of rats. We conducted surface plasmon resonance assay and molecular docking, and found that baicalein had a higher affinity with SUR1 protein (KD = 10.39 µM) than glibenclamide (KD = 24.32 µM), thus reducing the sensitivity of K-ATP channels to rotenone. Knockdown of SUR1 subunit reduced rotenone-induced apoptosis and damage of SH-SY5Y cells, confirming that SUR1 was an important target for slowing dopaminergic neuronal degeneration in PD. Taken together, we demonstrate for the first time that baicalein attenuates rotenone-induced SH-SY5Y cell apoptosis through binding to SUR1 and activating K-ATP channels.

Translational Potential of Baicalein in Mitigating RSL3-Induced Ferroptosis in Fibroblasts: Implications for Therapeutic Interventions.

Background: Ferroptosis is an iron-driven cell-death mechanism that plays a central role in various diseases. Recent studies have suggested that baicalein inhibits ferroptosis, making it a promising therapeutic candidate. Materials and Methods: Fibroblast cultures were treated with different agents to determine the effects of baicalein on ferroptosis. Ferroptosis-related gene expression, lipid peroxidation, and post-treatment cellular structural changes were measured using real-time quantitative polymerase chain reaction, C11-BODIPY dye, and transmission electron microscopy, respectively. Results: Baicalein significantly inhibited rat sarcoma virus selective lethal 3-induced ferroptosis in fibroblasts. Moreover, in baicalein-treated groups, reduced ferroptosis-related gene expression, decreased lipid peroxidation, and maintained cell structure was observed when compared with those of the controls. Discussion: The ability of baicalein to counteract RSL3-induced ferroptosis underscores its potential protective effects, especially in diseases characterized by oxidative stress and iron overload in fibroblasts. Conclusion: Baicalein may serve as a potent therapeutic agent against conditions in which ferroptosis is harmful. The compound's efficacy in halting RSL3-triggered ferroptosis in fibroblasts paves the way for further in vivo experiments and clinical trials.

Baicalein targets STMN1 to inhibit the progression of nasopharyngeal carcinoma via regulating the Wnt/ß-catenin pathway.

BACKGROUNDS: Nasopharyngeal carcinoma is a common malignancy in the head and neck. Baicalein has been reported to exert the anticancer effects on various cancers. In this study, our aim was to explore the function of baicalein in the development of nasopharyngeal carcinoma and further investigate the potential underlying mechanisms. METHODS: Cell Counting Kit (CCK)-8 assay, EdU assay, sphere formation assay, flow cytometry, and transwell invasion assay were conducted to determine cell proliferation, stemness, apoptosis, and invasion, respectively. Western blot was performed to examine the protein levels of PCNA, MMP9, STMN1, ß-catenin, and Wnt3A. The mRNA level of STMN1 was assessed using real-time quantitative polymerase chain reaction (RT-qPCR). Xenograft tumor model was carried out to evaluate the effects of baicalein on tumor growth in vivo. Immunohistochemistry (IHC) assay was used to detect the levels of PCNA, MMP9, and STMN1 in tumor tissues from mice. RESULTS: Baicalein significantly induced cell apoptosis and impeded cell proliferation, invasion, and stemness of nasopharyngeal carcinoma cells. STMN1 was highly expressed in nasopharyngeal carcinoma, and baicalein could directly downregulate STMN1 expression. STMN1 knockdown hampered the progression of nasopharyngeal carcinoma cells. Moreover, the effects of baicalein on cell proliferation, stemness, invasion, and apoptosis in nasopharyngeal carcinoma cells were harbored by STMN1 overexpression. Baicalein regulated STMN1 to inhibit the activation of the Wnt/ß-catenin pathway. SKL2001, an agonist of the Wnt/ß-catenin pathway, could reverse the effects of STMN1 knockdown on the progression of nasopharyngeal carcinoma. In addition, baicalein markedly impeded tumor growth in vivo. CONCLUSION: Baicalein regulated the STMN1/Wnt/ß-catenin pathway to restrain the development of nasopharyngeal carcinoma.

Antioxidant Efficacy of Hwangryunhaedok-tang through Nrf2 and AMPK Signaling Pathway against Neurological Disorders In Vivo and In Vitro.

Alzheimer's disease (AD) is a representative cause of dementia and is caused by neuronal loss, leading to the accumulation of aberrant neuritic plaques and the formation of neurofibrillary tangles. Oxidative stress is involved in the impaired clearance of amyloid beta (Aß), and Aß-induced oxidative stress causes AD by inducing the formation of neurofibrillary tangles. Hwangryunhaedok-tang (HHT, Kracie K-09®), a traditional herbal medicine prescription, has shown therapeutic effects on various diseases. However, the studies of HHT as a potential treatment for AD are insufficient. Therefore, our study identified the neurological effects and mechanisms of HHT and its key bioactive compounds against Alzheimer's disease in vivo and in vitro. In a 5xFAD mouse model, our study confirmed that HHT attenuated cognitive impairments in the Morris water maze (MWM) test and passive avoidance (PA) test. In addition, the prevention of neuron impairment, reduction in the protein levels of Aß, and inhibition of cell apoptosis were confirmed with brain tissue staining. In HT-22 cells, HHT attenuates tBHP-induced cytotoxicity, ROS generation, and mitochondrial dysfunction. It was verified that HHT exerts a neuroprotective effect by activating signaling pathways interacting with Nrf2, such as MAPK/ERK, PI3K/Akt, and LKB1/AMPK. Among the components, baicalein, a bioavailable compound of HHT, exhibited neuroprotective properties and activated the Akt, AMPK, and Nrf2/HO-1 pathways. Our findings indicate a mechanism for HHT and its major bioavailable compounds to treat and prevent AD and suggest its potential.

Inhibitory Efficacy of Main Components of Scutellaria baicalensis on the Interaction between Spike Protein of SARS-CoV-2 and Human Angiotensin-Converting Enzyme II.

Blocking the interaction between the SARS-CoV-2 spike protein and the human angiotensin-converting enzyme II (hACE2) protein serves as a therapeutic strategy for treating COVID-19. Traditional Chinese medicine (TCM) treatments containing bioactive products could alleviate the symptoms of severe COVID-19. However, the emergence of SARS-CoV-2 variants has complicated the process of developing broad-spectrum drugs. As such, the aim of this study was to explore the efficacy of TCM treatments against SARS-CoV-2 variants through targeting the interaction of the viral spike protein with the hACE2 receptor. Antiviral activity was systematically evaluated using a pseudovirus system. Scutellaria baicalensis (S. baicalensis) was found to be effective against SARS-CoV-2 infection, as it mediated the interaction between the viral spike protein and the hACE2 protein. Moreover, the active molecules of S. baicalensis were identified and analyzed. Baicalein and baicalin, a flavone and a flavone glycoside found in S. baicalensis, respectively, exhibited strong inhibitory activities targeting the viral spike protein and the hACE2 protein, respectively. Under optimized conditions, virus infection was inhibited by 98% via baicalein-treated pseudovirus and baicalin-treated hACE2. In summary, we identified the potential SARS-CoV-2 inhibitors from S. baicalensis that mediate the interaction between the Omicron spike protein and the hACE2 receptor. Future studies on the therapeutic application of baicalein and baicalin against SARS-CoV-2 variants are needed.

Baicalin and Baicalein Enhance Cytotoxicity, Proapoptotic Activity, and Genotoxicity of Doxorubicin and Docetaxel in MCF-7 Breast Cancer Cells.

Breast cancer is a major health concern and the leading cause of death among women worldwide. Standard treatment often involves surgery, radiotherapy, and chemotherapy, but these come with side effects and limitations. Researchers are exploring natural compounds like baicalin and baicalein, derived from the Scutellaria baicalensis plant, as potential complementary therapies. This study investigated the effects of baicalin and baicalein on the cytotoxic, proapoptotic, and genotoxic activity of doxorubicin and docetaxel, commonly used chemotherapeutic drugs for breast cancer. The analysis included breast cancer cells (MCF-7) and human endothelial cells (HUVEC-ST), to assess potential effects on healthy tissues. We have found that baicalin and baicalein demonstrated cytotoxicity towards both cell lines, with more potent effects observed in baicalein. Both flavonoids, baicalin (167 µmol/L) and baicalein (95 µmol/L), synergistically enhanced the cytotoxic, proapoptotic, and genotoxic activity of doxorubicin and docetaxel in breast cancer cells. In comparison, their effects on endothelial cells were mixed and depended on concentration and time. The results suggest that baicalin and baicalein might be promising complementary agents to improve the efficacy of doxorubicin and docetaxel anticancer activity. However, further research is needed to validate their safety and efficacy in clinical trials.

Baicalein enhances immune response in TNBC by inhibiting leptin expression of adipocytes.

Triple-negative breast cancer (TNBC) is a special pathological type of breast cancer (BC) with poor prognosis. Obesity is shown to be involved in TNBC tumor progression. The interaction between obesity and BC has generated great attention in recent years, however, the mechanism is still unclear. Here, we showed that leptin secreted by adipocytes upregulated PD-L1 expression in TNBC through the p-STAT3 signaling pathway and that baicalein inhibited PD-L1 expression in tumor microenvironment by suppressing leptin transcription of adipocytes. Collectively, our findings suggest that leptin may be the key factor participating in obesity-related tumor progression and that baicalein can break through the dilemma to boost the anti-tumor immune response.

Network pharmacology and bioinformatics analysis on the underlying mechanisms of baicalein against oral squamous cell carcinoma.

BACKGROUND AND AIMS: This study performed a network pharmacology analysis to explore the potential anticancer activity of baicalein against oral squamous cell carcinoma (OSCC). METHODS: The differentially expressed genes in OSCC were identified by the OSCC, and the key module related to OSCC was acquired by the weighted gene co-expression network analysis from GSE30784. Baicalein targets were obtained from GeneCards, SwissTargetPrediction and TCMSP (the traditional Chinese medicine systems pharmacology database and analysis platform) databases. Apart from GSE30784, OSCC-related genes were acquired from the Comparative Toxicogenomics Database and DisGeNET platform. The baicalein targets and OSCC-related genes were overlapped to acquire the drug-disease interaction genes. We input the candidate drug-disease interaction genes into the STRING database and created the protein-protein interaction network. The hub genes in the network were identified by cytoHubba. The expression levels of hub genes between cancer tissues and normal tissues were evaluated based on The Cancer Genome Atlas. Moreover, we performed the cancer immune infiltration analysis and evaluated the association between the expression of HIF1A and the abundance of infiltrating immune cells. The molecular docking between HIFA and baicalein was also performed and visualized. Additionally, the enrichment analysis was performed based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database. RESULTS: After overlapping the candidate baicalein targets with OSCC-related genes, 34 candidate drug-disease interaction genes were obtained. cytoHubba identified the top 10 genes with high centrality measures from the network, including AKT1, CD44, EGFR, HIF1A, IGF1, MMP2, MYC, PTGS2, STAT3 and TP53. The enriched biological process terms included regulation of apoptotic signaling pathway, regulation of cysteine-type endopeptidase activity and cellular response to chemical stress. The top five enriched pathways comprised Kaposi sarcoma-associated herpesvirus infection, hepatitis C, p53 signaling pathway, Epstein-Barr virus infection and proteoglycans in cancer. The expression of HIF1A was positively associated with the infiltration levels of CD4 + T cells (cor = 0.131, p = 0.004) and dendritic cells (cor = 0.098, p = 0.03), whereas negatively associated with B cells (cor = -0.098, p = 0.03). CONCLUSION: Our results suggested that baicalein might be a candidate drug against OSCC. More studies are necessary to validate its anticancer effect and explore the underlying mechanisms.

Induction of DNMT1-dependent demethylation of SHP-1 by the natural flavonoid compound Baicalein overcame Imatinib-resistance in CML CD34+ cells.

BACKGROUND: The most significant cause of treatment failure in chronic myeloid leukemia (CML) is a persistent population of minimal residual cells. Emerging evidences showed that methylation of SHP-1 contributed to Imatinib (IM) resistance. Baicalein was reported to have an effect on reversal of chemotherapeutic agents resistance. However, the molecular mechanism of Baicalein on JAK2/STAT5 signaling inhibition against drug resistance in bone marrow (BM) microenvironment that had not been clearly revealed. METHODS: We co-cultured hBMSCs and CML CD34+ cells as a model of SFM-DR. Further researches were performed to clarify the reverse mechanisms of Baicalein on SFM-DR model and engraftment model. The apoptosis, cytotoxicity, proliferation, GM-CSF secretion, JAK2/STAT5 activity, the expression of SHP-1 and DNMT1 were analyzed. To validate the role of SHP-1 on the reversal effect of Baicalein, the SHP-1 gene was over-expressed by pCMV6-entry shp-1 and silenced by SHP-1 shRNA, respectively. Meanwhile, the DNMT1 inhibitor decitabine was used. The methylation extent of SHP-1 was evaluated using MSP and BSP. The molecular docking was replenished to further explore the binding possibility of Baicalein and DNMT1. RESULTS: BCR/ABL-independent activation of JAK2/STAT5 signaling was involved in IM resistance in CML CD34+ subpopulation. Baicalein significantly reversed BM microenvironment-induced IM resistance not through reducing GM-CSF secretion, but interfering DNMT1 expression and activity. Baicalein induced DNMT1-mediated demethylation of the SHP-1 promoter region, and subsequently activated SHP-1 re-expression, which resulted in an inhibition of JAK2/STAT5 signaling in resistant CML CD34+ cells. Molecular docking model indicated that DNMT1 and Baicalein had binding pockets in 3D structures, which further supported Baicalein might be a small-molecule inhibitor targeting DNMT1. CONCLUSIONS: The mechanism of Baicalein on improving the sensitivity of CD34+ cells to IM might be correlated with SHP-1 demethylation by inhibition of DNMT1 expression. These findings suggested that Baicalein could be a promising candidate by targeting DNMT1 to eradicate minimal residual disease in CML patients. Video Abstract.

Baicalein Attenuates Neuroinflammation in LPS-Treated BV-2 Cells by Inhibiting Glycolysis via STAT3/c-Myc Pathway.

More and more evidence shows that metabolic reprogramming is closely related to the occurrence of AD. The metabolic conversion of oxidative phosphorylation into glycolysis will aggravate microglia-mediated inflammation. It has been demonstrated that baicalein could inhibit neuroinflammation in LPS-treated BV-2 microglial cells, but whether the anti-neuroinflammatory mechanisms of baicalein were related to glycolysis is unclear. Our results depicted that baicalein significantly inhibited the levels of nitric oxide (NO), interleukin-6 (IL-6), prostaglandin 2 (PGE2) and tumor necrosis factor (TNF-α) in LPS-treated BV-2 cells. 1H-NMR metabolomics analysis showed that baicalein decreased the levels of lactic acid and pyruvate, and significantly regulated glycolytic pathway. Further study revealed that baicalein significantly inhibited the activities of glycolysis-related enzymes including hexokinase (HK), 6-phosphate kinase (6-PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), and inhibited STAT3 phosphorylation and c-Myc expression. By using of STAT3 activator RO8191, we found that baicalein suppressed the increase of STAT3 phosphorylation and c-Myc expression triggered by RO8191, and inhibited the increased levels of 6-PFK, PK and LDH caused by RO8191. In conclusion, these results suggested that baicalein attenuated the neuroinflammation in LPS-treated BV-2 cells by inhibiting glycolysis through STAT3/c-Myc pathway.

Baicalein sensitizes triple negative breast cancer MDA-MB-231 cells to doxorubicin via autophagy-mediated down-regulation of CDK1.

Triple negative breast cancer (TNBC) is a kind of refractory cancer with poor response to conventional chemotherapy. Recently, the combination of baicalein and doxorubicin was reported to exert a synergistic antitumor effect on breast cancer. However, the underlying mechanism how baicalein sensitizes breast cancer cells to doxorubicin remains to be elucidated. Here, it was found that 20 µM baicalein increased the autophagy markers including the ratio of LC3B II/I, GFP-LC3 punctate aggregates and down-regulation of p62 expression, and up-regulated mitophagy marker PINK1 and Parkin in TNBC MDA-MB-231 cells as well. In contrast, doxorubicin decreased the levels of autophagy markers, and significantly up-regulated CDK1 in MDA-MB-231 cells. Pretreatment with baicalein markedly inhibited the doxorubicin-induced decrease in autophagy markers and up-regulation of CDK1, which was reversed by the autophagy inhibitor 3-Methyladenine. Moreover, baicalein alleviated the doxorubicin-induced expression and phosphorylation (at Ser616) of mitochondrial fission protein Drp1. Intriguingly, the autophagy inhibitor 3-Methyladenine also significantly weakened the effect of baicalein on doxorubicin-induced viability decrease and apoptosis in MDA-MB-231 cells. Taken together, our data indicate that baicalein improves the chemosensitivity of TNBC cells to doxorubicin through promoting the autophagy-mediated down-regulation of CDK1, also suggest a novel strategy for prevention of TNBC in the future.

Baicalin suppressed necroptosis and inflammation against chlorpyrifos toxicity; involving in ER stress and oxidative stress in carp gills.

Chlorpyrifos (CPF) has caused large-scale pollution worldwide and posed a threat to non-target organisms. Baicalein (BAI) is a flavonoid extract with anti-oxidant and anti-inflammatory activities. The gills are the mucosal immune organ and the first physical barrier of fish. However, it is not clear whether BAI counteracts organophosphorus pesticide CPF exposure-caused gill damage. Therefore, we established the CPF exposure and BAI intervention models by adding 23.2 µg/L CPF in water and/or 0.15 g/kg BAI in feed for 30 days. The results showed that CPF exposure could cause gill histopathology lesions. Moreover, CPF exposure led to endoplasmic reticulum (ER) stress, caused oxidative stress and Nrf2 pathway activation, and triggered NF-κB-mediated inflammation reaction and necroptosis in carp gills. BAI adding effectively relieved the pathological changes, and lighten inflammation and necroptosis involving in the elF2α/ATF4 and ATF6 pathways through binding to GRP78 protein. Moreover, BAI could ease oxidative stress, but did not affect Nrf2 pathway in carp gills under CPF exposure. These results suggested that BAI feeding could alleviate necroptosis and inflammation against chlorpyrifos toxicity through elF2α/ATF4 and ATF6 axis. The results partially explained the poisoning effect of CPF, and showed BAI could be act as an antidote for organophosphorus pesticides.

Efficient production of the glycosylated derivatives of baicalein in engineered Escherichia coli.

Baicalein-7-O-glucoside and baicalein-7-O-rhamnoside have been proven to possess many pharmacological activities and are potential candidate drug leads and herb supplements. However, their further development is largely limited due to low content in host plants. Few studies reported that both bioactive plant components are prepared through the bioconversion of baicalein that is considered as the common biosynthetic precursor of both compounds. Herein, we constructed a series of the engineered whole-cell bioconversion systems in which the deletion of competitive genes and the introduction of exogenous UDP-glucose supply pathway, glucosyltransferase, rhamnosyltransferase, and the UDP-rhamnose synthesis pathway are made. Using these engineered strains, the precursor baicalein is able to be transformed into baicalein-7-O-glucoside and baicalein-7-O-rhamnoside, with high-titer production, respectively. The further optimization of fermentation conditions led to the final production of 568.8 mg/L and 877.0 mg/L for baicalein-7-O-glucoside and baicalein-7-O-rhamnoside, respectively. To the best of our knowledge, it is the highest production in preparation of baicalein-7-O-glucoside from baicalein so far, while the preparation of baicalein-7-O-rhamnoside is the first reported via bioconversion approach. Our study provides a reference for the industrial production of high-value products baicalein-7-O-glucoside and baicalein-7-O-rhamnoside using engineered E. coli. KEY POINTS: • Integrated design for improving the intracellular UDP-glucose pool • High production of rare baicalein glycosides in the engineered E. coli • Baicalein-7-O-glucoside and baicalein-7-O-rhamnoside.