TMF suppresses chondrocyte hypertrophy in osteoarthritic cartilage by mediating the FOXO3a/BMPER pathway.

Osteoarthritis (OA) is a disease of the joints, characterized by chronic inflammation, cartilage destruction and extracellular matrix (ECM) remodeling. Aberrant chondrocyte hypertrophy promotes cartilage destruction and OA development. Collagen X, the biomarker of chondrocyte hypertrophy, is upregulated by runt-related transcription factor 2 (Runx2), which is mediated by the bone morphogenetic protein 4 (BMP4)/Smad1 signaling pathway. BMP binding endothelial regulator (BMPER), a secreted glycoprotein, acts as an agonist of BMP4. 5,7,3',4'-tetramethoxyflavone (TMF) is a natural flavonoid derived from Murraya exotica L. Results of our previous study demonstrated that TMF exhibits chondroprotective effects against OA development through the activation of Forkhead box protein O3a (FOXO3a) expression. However, whether TMF suppresses chondrocyte hypertrophy through activation of FOXO3a expression and inhibition of BMPER/BMP4/Smad1 signaling remains unknown. Results of the present study revealed that TMF inhibited collagen X and Runx2 expression, inhibited BMPER/BMP4/Smad1 signaling, and activated FOXO3a expression; thus, protecting against chondrocyte hypertrophy and OA development. However, BMPER overexpression and FOXO3a knockdown impacted the protective effects of TMF. Thus, TMF inhibited chondrocyte hypertrophy in OA cartilage through mediating the FOXO3a/BMPER signaling pathway.

Geniposide alleviates cholesterol-induced endoplasmic reticulum stress and apoptosis in osteoblasts by mediating the GLP-1R/ABCA1 pathway.

BACKGROUND: Cholesterol (CHO) is an essential component of the body. However, high CHO levels in the body can damage bone mass and promote osteoporosis. CHO accumulation can cause osteoblast apoptosis, which has a negative effect on bone formation. The pathogenesis of osteoporosis is a complicate process that includes oxidative stress, endoplasmic reticulum (ER) stress, and inflammation. Geniposide (GEN) is a natural compound with anti-osteoporotic effect. However, the roles of GEN in osteopathogenesis are still unclear. Our previous studies demonstrated that GEN could reduce the accumulation of CHO in osteoblasts and the activation of ER stress in osteoblasts. However, the molecular mechanism of GEN in inhibiting CHO-induced apoptosis in osteoblasts needs to be further investigated. METHODS: MC3T3-E1 cells were treated with osteogenic induction medium (OIM). Ethanol-solubilized cholesterol (100 µM) was used as a stimulator, and 10 µM and 25 µM geniposide was added for treatment. The alterations of protein expression were detected by western blot, and the cell apoptosis was analyzed by a flow cytometer. RESULTS: CHO promoted osteoblast apoptosis by activating ER stress in osteoblasts, while GEN alleviated the activation of ER stress and reduced osteoblast apoptosis by activating the GLP-1R/ABCA1 pathway. Inhibition of ABCA1 or GLP-1R could eliminate the protective activity of GEN against CHO-induced ER stress and osteoblast apoptosis. CONCLUSION: GEN alleviated CHO-induced ER stress and apoptosis in osteoblasts by mediating the GLP-1R/ABCA1 pathway.

TMF inhibits extracellular matrix degradation by regulating the C/EBPß/ADAMTS5 signaling pathway in osteoarthritis.

Osteoarthritis (OA) is a chronic joint disease, characterized by degenerative destruction of articular cartilage. Chondrocytes, the unique cell type in cartilage, mediate the metabolism of extracellular matrix (ECM), which is mainly constituted by aggrecan and type II collagen. A disintegrin and metalloproteinase with thrombospondin 5 (ADAMTS5) is an aggrecanase responsible for the degradation of aggrecan in OA cartilage. CCAAT/enhancer binding protein ß (C/EBPß), a transcription factor in the C/EBP family, has been reported to mediate the expression of ADAMTS5. Our previous study showed that 5,7,3',4'-tetramethoxyflavone (TMF) could activate the Sirt1/FOXO3a signaling in OA chondrocytes. However, whether TMF protected against ECM degradation by down-regulating C/EBPß expression was unknown. In this study, we found that aggrecan expression was down-regulated, and ADAMTS5 expression was up-regulated. Knockdown of C/EBPß could up-regulate aggrecan expression and down-regulate ADAMTS5 expression in IL-1ß-treated C28/I2 cells. TMF could compromise the effects of C/EBPß on OA chondrocytes by activating the Sirt1/FOXO3a signaling. Conclusively, TMF exhibited protective activity against ECM degradation by mediating the Sirt1/FOXO3a/C/EBPß pathway in OA chondrocytes.

C/EBPß: The structure, regulation, and its roles in inflammation-related diseases.

Inflammation, a mechanism of the human body, has been implicated in many diseases. Inflammatory responses include the release of inflammatory mediators by activating various signaling pathways. CCAAT/enhancer binding protein ß (C/EBPß), a transcription factor in the C/EBP family, contains the leucine zipper (bZIP) domain. The expression of C/EBPß is mediated at the transcriptional and post-translational levels, such as phosphorylation, acetylation, methylation, and SUMOylation. C/EBPß has been involved in inflammatory responses by mediating several signaling pathways, such as MAPK/NF-κB and IL-6/JAK/STAT3 pathways. C/EBPß plays an important role in the pathological development of inflammation-related diseases, such as osteoarthritis, pneumonia, hepatitis, inflammatory bowel diseases, and rheumatoid arthritis. Here, we comprehensively discuss the structure and biological effects of C/EBPß and its role in inflammatory diseases.

Correction: Zheng et al. Geniposide Ameliorated Dexamethasone-Induced Cholesterol Accumulation in Osteoblasts by Mediating the GLP-1R/ABCA1 Axis. Cells 2021, 10, 3424.

The authors wish to make the following changes to their paper [...].

Geniposide ameliorates glucocorticoid-induced osteoblast apoptosis by activating autophagy.

Long-term exposure to glucocorticoid (GC) contributes to the development of osteoporosis (OP), which is correlated with the risk of fracture. Pathologically, GC-induced bone loss is associated with osteoblast apoptosis. Geniposide (GEN), a natural occurring compound derived from Eucommia ulmoides, has been reported to ameliorate dexamethasone (DEX)-induced OP. Our previous study shows that GEN exhibits protective activity against DEX-induced OP by attenuating endoplasmic reticulum stress and decreasing apoptosis in osteoblasts. However, the molecular mechanisms of GEN in inhibiting DEX-induced osteoblast apoptosis still need further elucidation. In this article, a molecular target network of GEN against OP was screened. It was found that GEN might interact with OP by mediating PI3K/AKT pathway, which is the upstream factor in regulating autophagy. GEN exhibited protective activity against DEX-induced apoptosis by activating autophagy in vivo and in vitro. Blockage of autophagy, activation of PI3K/AKT/mTOR pathway, or inhibition of GLP-1R activity could eliminate the protective effects of GEN against DEX-induced apoptosis. Collectively, GEN ameliorated DEX-induced osteoblast apoptosis by activating autophagy through GLP-1R/PI3K/AKT/mTOR pathway.

7-Ketocholesterol Induces Oxiapoptophagy and Inhibits Osteogenic Differentiation in MC3T3-E1 Cells.

7-Ketocholesterol (7KC) is one of the oxysterols produced by the auto-oxidation of cholesterol during the dysregulation of cholesterol metabolism which has been implicated in the pathological development of osteoporosis (OP). Oxiapoptophagy involving oxidative stress, autophagy, and apoptosis can be induced by 7KC. However, whether 7KC produces negative effects on MC3T3-E1 cells by stimulating oxiapoptophagy is still unclear. In the current study, 7KC was found to significantly decrease the cell viability of MC3T3-E1 cells in a concentration-dependent manner. In addition, 7KC decreased ALP staining and mineralization and down-regulated the protein expression of OPN and RUNX2, inhibiting osteogenic differentiation. 7KC significantly stimulated oxidation and induced autophagy and apoptosis in the cultured MC3T3-E1 cells. Pretreatment with the anti-oxidant acetylcysteine (NAC) could effectively decrease NOX4 and MDA production, enhance SOD activity, ameliorate the expression of autophagy-related factors, decrease apoptotic protein expression, and increase ALP, OPN, and RUNX2 expression, compromising 7KC-induced oxiapoptophagy and osteogenic differentiation inhibition in MC3T3-E1 cells. In summary, 7KC may induce oxiapoptophagy and inhibit osteogenic differentiation in the pathological development of OP.

Integration of UPLC-QE-MS/MS and network pharmacology to investigate the active components and action mechanisms of tea cake extract for treating cough.

The active components and mechanisms of tea cake extract (TCE) were investigated for treating cough. The components of TCE were tentatively identified by ultrahigh-performance liquid chromatography coupled with Q-Exactive MS/MS (UPLC-QE-MS/MS), whose targets were obtained from the Swiss Target Prediction database and the Traditional Chinese Medicine Systems Pharmacology database and analysis platform. Cough-related targets were retrieved from the Gene Cards and Online Mendelian Inheritance in Man database. After the intersection targets had been obtained, enrichment analysis of Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were determined, and the protein-protein interaction network and active compound-intersection target-KEGG pathway network were constructed. Core active compounds and their targets were validated with molecular docking. A total of 78 compounds were identified from TCE, including 24 flavonoids, 17 phenolic acids, 10 alkaloids, seven organic acids, five triterpenes, five amino acids, five coumarins, three carbohydrates, one anthraquinone and one other. A total of 347 intersection targets were obtained. The top five GO terms with the most significant P-values were responses to oxygen-containing compounds and organic substances, chemical and cellular responses to chemical stimulus, and regulation of biological quality. The top five KEGG pathways with the most significant P-values were: the PI3K-Akt signaling pathway, lipids and atherosclerosis, human cytomegalovirus infection, fluid shear stress and atherosclerosis, and proteoglycans in cancer. The top five core active compounds were quercetin, genistein, luteolin, kaempferol and emodin. The top five core targets were protein kinase B (Akt1), prostaglandin-endoperoxide synthase 2 (PTGS2), mitogen-activated protein kinase 1/3 (MAPK1/3) and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1). The top five core active compounds could stably bind to their targets with LibDockScores higher than 100. Tea cake extract plays the antitussive role via multiple components and targets. Core targets (AKT1, MAPK1, MAPK3 and PIK3R1) and core components (quercetin, genistein, luteolin and kaempferol) involved in the PI3K-Akt signaling pathway are worth more attention in subsequent validation experiments.

The pharmacokinetic property and pharmacological activity of acteoside: A review.

Acteoside (AC), a phenylpropanoid glycoside isolated from many dicotyledonous plants, has been demonstrated various pharmacological activities, including anti-oxidation, anti-inflammation, anti-cancer, neuroprotection, cardiovascular protection, anti-diabetes, bone and cartilage protection, hepatoprotection, and anti-microorganism. However, AC has a poor bioavailability, which can be potentially improved by different strategies. The health-promoting characteristics of AC can be attributed to its mediation in many signaling pathways, such as MAPK, NF-κB, PI3K/AKT, TGFß/Smad, and AMPK/mTOR. Interestingly, docking simulation study indicates that AC can be an effective candidate to inhibit the activity of SARS-CoV2 main protease and protect against COVID-19. Many clinical trials for AC have been investigated, and it shows great potentials in drug development.

Geniposide ameliorated dexamethasone-induced endoplasmic reticulum stress and mitochondrial apoptosis in osteoblasts.

ETHNOPHARMACOLOGICAL RELEVANCE: Eucommia ulmoides Oliver has been traditionally used for treatment of various diseases, including osteoporosis, knee pain, and paralysis. The extract of Eucommia ulmoides has been reported to stimulate the bone formation and suppress the bone resorption, leading to protection against osteoporosis (OP). Geniposide (GEN) has been considered as one of the effective compounds responsible for the therapeutic efficacy of Eucommia ulmoides against OP. AIM OF THE STUDY: To explore whether GEN protected against dexamethasone (DEX)-induced osteoporosis (OP) by activating NRF2 expression and inhibiting endoplasmic reticulum (ER) stress. MATERIALS AND METHODS: The DEX-induced rat OP models were duplicated. The pathological changes were examined by histological/immunohistochemical evaluation and micro-computed tomography (micro-CT) assessment. Apoptosis was detected by a flow cytometer. Mitochondrial Ca2+ concentrations and mitochondrial membrane potential were detected. Western blot assays were used to detect the protein expression. RESULTS: GEN effectively reversed DEX-induced pathological changes of trabecular bone in rats. In addition, the DEX-increased expression of ATF4/CHOP was also ameliorated. In MC3T3-E1 cells, DEX promoted endoplasmic reticulum (ER) stress and mitochondrial apoptosis. Inhibition of ER stress abolished the induction of apoptosis by DEX. Similarly, GEN significantly ameliorated DEX-induced mitochondrial apoptosis. The possible underlying mechanism might be associated with the pharmacological effects of GEN on activating the expression of NRF2 and alleviating ER stress in DEX-treated MC3T3-E1 cells. CONCLUSION: GEN ameliorated DEX-induced ER stress and mitochondrial apoptosis in osteoblasts.

Geniposide Ameliorated Dexamethasone-Induced Cholesterol Accumulation in Osteoblasts by Mediating the GLP-1R/ABCA1 Axis.

BACKGROUND: Overexposure to glucocorticoid (GC) produces various clinical complications, including osteoporosis (OP), dyslipidemia, and hypercholesterolemia. Geniposide (GEN) is a natural iridoid compound isolated from Eucommia ulmoides. Our previous study found that GEN could alleviate dexamethasone (DEX)-induced differentiation inhibition of MC3T3-E1 cells. However, whether GEN protected against Dex-induced cholesterol accumulation in osteoblasts was still unclear. METHODS: DEX was used to induce rat OP. Micro-CT data was obtained. The ALP activity and mineralization were determined by the staining assays, and the total intracellular cholesterol was determined by the ELISA kits. The protein expression was detected by western blot. RESULTS: GEN ameliorated Dex-induced micro-structure damages and cell differentiation inhibition in the bone trabecula in rats. In MC3T3-E1 cells, Dex enhanced the total intracellular cholesterol, which reduced the activity of cell proliferation and differentiation. Effectively, GEN decreased DEX-induced cholesterol accumulation, enhanced cell differentiation, and upregulated the expression of the GLP-1R/ABCA1 axis. In addition, inhibition of ABAC1 expression reversed the actions of GEN. Treatment with Exendin9-39, a GLP-1R inhibitor, could abrogate the protective activity of GEN. CONCLUSIONS: GEN ameliorated Dex-induced accumulation of cholesterol and inhibition of cell differentiation by mediating the GLP-1R/ABCA1 axis in MC3T3-E1 cells.

The discovery and development of transthyretin amyloidogenesis inhibitors: what are the lessons?

Transthyretin (TTR) is associated with several human amyloid diseases. Various kinetic stabilizers have been developed to inhibit the dissociation of TTR tetramer and the formation of amyloid fibrils. Most of them are bisaryl derivatives, natural flavonoids, crown ethers and carborans. In this review article, we focus on TTR tetramer stabilizers, genetic therapeutic approaches and fibril remodelers. The binding modes of typical bisaryl derivatives, natural flavonoids, crown ethers and carborans are discussed. Based on knowledge of the binding of thyroxine to TTR tetramer, many stabilizers have been screened to dock into the thyroxine binding sites, leading to TTR tetramer stabilization. Particularly, those stabilizers with unique binding profiles have shown great potential in developing the therapeutic management of TTR amyloidogenesis.

Kaempferol Ameliorates the Inhibitory Activity of Dexamethasone in the Osteogenesis of MC3T3-E1 Cells by JNK and p38-MAPK Pathways.

Kaempferol has been reported to exhibit beneficial effect on the osteogenic differentiation in mesenchymal stem cells (MSC) and osteoblasts. In our previous study, dexamethasone (DEX) demonstrated inhibitory effect on MC3T3-E1 cells differentiation. In this study, we mainly explored the protective effect of kaempferol on the inhibitory activity of DEX in the osteogenesis of MC3T3-E1 cells. We found that kaempferol ameliorated the proliferation inhibition, cell cycle arrest, and cell apoptosis and increased the activity of alkaline phosphatase (ALP) and the mineralization in DEX-treated MC3T3-E1 cells. Kaempferol also significantly enhanced the expression of osterix (Osx) and runt-related transcription factor 2 (Runx2) in MC3T3-E1 cells treated with DEX. In addition, kaempferol attenuated DEX-induced reduction of cyclin D1 and Bcl-2 expression and elevation of p53 and Bax expression. Kaempferol also activated JNK and p38-MAPK pathways in DEX-treated MC3T3-E1 cells. Furthermore, kaempferol improved bone mineralization in DEX-induced bone damage in a zebrafish larvae model. These data suggested that kaempferol ameliorated the inhibitory activity of DEX in the osteogenesis of MC3T3-E1 cells by activating JNK and p38-MAPK signaling pathways. Kaempferol exhibited great potentials in developing new drugs for treating glucocorticoid-induced osteoporosis.

5,7,3',4'-tetramethoxyflavone ameliorates cholesterol dysregulation by mediating SIRT1/FOXO3a/ABCA1 signaling in osteoarthritis chondrocytes.

Dyslipidemia has been associated with the development of osteoarthritis. Our previous study found that 5,7,3',4'-tetramethoxyflavone (TMF) exhibited protective activities against the pathological changes of osteoarthritis. Aim: To investigate the roles of TMF in regulating ABCA1-mediated cholesterol metabolism. Methods: Knockdown and overexpression were employed to study gene functions. Protein-protein interaction was investigated by co-immunoprecipitation, and the subcellular locations of proteins were studied by immunofluorescence. Results: IL-1ß decreased ABCA1 expression and induced apoptosis. Therapeutically, TMF ameliorated the effects of IL-1ß. FOXO3a knockdown expression abrogated the effects of TMF, and FOXO3a overexpression increased ABCA1 expression by interacting with LXRα. TMF promoted FOXO3a nuclear translocation by activating SIRT1 expression. Conclusions: TMF ameliorates cholesterol dysregulation by increasing the expression of FOXO3a/LXRα/ABCA1 signaling through SIRT1 in C28/I2 cells.

Lifelong Bilingualism Functions as an Alternative Intervention for Cognitive Reserve Against Alzheimer's Disease.

Bilingualism has been reported to significantly delay the onset of dementia and plays an important role in the management of Alzheimer's disease (AD), a condition inducing impairment in the brain network and cognitive decline. Cognitive reserve is associated with the adaptive maintenance of neural functions by protecting against neuropathology. Bilingualism acts as a beneficial environmental factor contributing to cognitive reserve, although some potential confounding variables still need further elucidation. In this article, the relationship between bilingualism and cognitive reserve is discussed, interpreting the advantage of bilingualism in protecting against cognitive decline. In addition, the possible brain and biochemical mechanisms, supporting the advantageous effects of bilingualism in delaying the onset of dementia, involved in bilingualism are reviewed. Effectively, bilingualism can be considered as a pharmacological intervention with no side effects. However, the investigation of the pharmacological parameters of bilingualism is still at an early stage.

Kaempferol ameliorates the regulatory effects of PVT1/miR-214 on epithelial-mesenchymal transition through the PAK4/ß-catenin axis in SRA01/04 cells.

Aim: To investigate whether kaempferol exhibits a protective effect on high glucose-induced epithelial-mesenchymal transition (EMT) by mediating the PVT1/miR-214 and PAK4/ß-catenin pathways in SRA01/04 cells. Methods & methods: qRT-PCR and western blot assays were used for gene and protein determination, and migration and invasion assays were conducted. A coimmunoprecipitation assay was used for determining protein interactions. Results: High glucose effectively upregulated PVT1 expression, downregulated miR-214 expression and promoted cell migration and invasion. Kaempferol attenuated high glucose-induced EMT by increasing PVT1 expression and decreasing miR-214 expression. PAK4 was identified as a direct target of miR-214. PAK4 overexpression could rescue the effects of PVT1 deficiency on SRA01/04 cells. Conclusion: Kaempferol ameliorated the regulatory effects of PVT1/miR-214 on high glucose-induced EMT through PAK4/ß-catenin in SRA01/04 cells.

Metabolism and pharmacological activities of the natural health-benefiting compound diosmin.

Diosmin is a famous natural flavonoid for treating chronic venous insufficiency and varicose veins. Recently, extensive study has indicated that diosmin possesses diverse pharmacological activities, including anti-inflammation, anti-oxidation, anti-diabetes, anti-cancer, anti-microorganism, liver protection, neuro-protection, cardiovascular protection, renoprotection, and retinal protection activities. Due to its low water solubility, diosmin is dramatically limited in clinical application. Expectedly, many potential strategies have been developed for improving its pharmacokinetic values and bioavailability. This health-benefiting compound has been explored as the major component of Daflon and micronized purified flavonoid fraction (MPFF), which have been used in clinics to improve micro-circulation. However, no specific drug targets for diosmin are reported, although some potential factors have been involved in screening, such as P-glycoprotein (P-gp), IKKß, acetylcholinesterase (AChE), and aldose reductase (AR). More investigations on the underlying mechanisms of diosmin in mediating cellular processes with high specificity is still needed.