Formononetin improves the inflammatory response and bone destruction in knee joint lesions by regulating the NF-kB and MAPK signaling pathways.

Formononetin (FMN) is a phytoestrogen that belongs to the isoflavone family. It has antioxidant and anti-inflammatory effects, as well as, many other biological activities. Existing evidence has aroused interest in its ability to protect against osteoarthritis (OA) and promote bone remodeling. To date, research on this topic has not been thorough and many issues remain controversial. Therefore, the purpose of our study was to explore the protective effect of FMN against knee injury and clarify the possible molecular mechanisms. We found that FMN inhibited osteoclast formation induced by receptor activator of NF-κB ligand (RANKL). Inhibition of the phosphorylation and nuclear translocation of p65 in the NF-κB signaling pathway plays a role in this effect. Similarly, during the inflammatory response of primary knee cartilage cells activated by IL-1ß, FMN inhibited the NF-κB signaling pathway and the phosphorylation of the ERK and JNK proteins in the MAPK signaling pathway to suppress the inflammatory response. In addition, in vivo experiments showed that both low- and high-dose FMN had a clear protective effect against knee injury in the DMM (destabilization of the medial meniscus) model, and the therapeutic effect of high-dose FMN was stronger. In conclusion, these studies provide evidence of the protective effect of FMN against knee injury.

Naringin as a plant-derived bitter tastant promotes proliferation of cultured human airway epithelial cells via activation of TAS2R signaling.

BACKGROUND: Bitter tastants can activate bitter taste receptors (TAS2Rs) and thus initiate relaxation of airway smooth muscle cells (ASMCs), which have great potential in the development of novel bronchodilator drugs for asthma therapy. However, the canonical bitter substance, denatonium is known to induce apoptosis of airway epithelial cells (AECs), indicating that other bitter tastants may also impair the epithelial integrity to prevent hazardous particulate matters such as coronaviruses. Therefore, any bitter tastants intended for treating airway disease should be carefully evaluated for potential toxicity to AECs. HYPOTHESIS/PURPOSE: Considering the vast diversity of bitter tastants in nature and different types of TAS2Rs expressed in airway cells, we hypothesized that there must be some natural bitter tastants to be not only potent in inducing relaxation of ASMCs but also unharmful to AECs. STUDY DESIGN AND METHODS: Here we evaluated a group of bitter flavonoids that are derived from fruits and commonly used in traditional herbal medicine, including apigenin, hesperetin, kaempferol, naringenin, quercetin, and naringin, for their effects on the proliferation of human airway epithelial-like (16HBE14o-, BEAS-2B, and A549) cells cultured in vitro. Cell proliferation and associated signaling pathways were assessed by cell counting, ATP assay, cell cycling assay, quantitative RT-PCR, Fluo-4 labeling, and fluorescence resonance energy transfer, respectively. RESULTS: The results show that five of the six tested bitter tastants inhibited, but only naringin promoted the proliferation of the 16HBE14o-, BEAS-2B, and A549 cells at the dose of a few hundred micromoles. Furthermore, the naringin-promoted proliferation of the 16HBE14o- cells was associated with enhanced cell cycle progression, mRNA expression of cyclin E, and evoked calcium signaling/ERK signaling, which were all attenuated by inhibition of the TAS2R signaling pathways with specific blockers. CONCLUSION: These findings indicate that although the majority of the bitter flavonoids may inhibit the proliferation of AECs, naringin emerged as one to promote the proliferation of AECs via cell cycle progression and TAS2R-activated intracellular signaling. It suggests that naringin and not a few other bitter tastants can be proven with nontoxicity to the airway epithelial structure and function, which provides further confidence in the development of safe and effective TAS2R-based bronchodilators for asthma therapy.

Sanguinarine Rapidly Relaxes Rat Airway Smooth Muscle Cells Dependent on TAS2R Signaling.

Excessive contraction of airway smooth muscle cells (ASMCs) is a hallmark feature of asthma. Intriguing, the activation of bitter taste receptor (TAS2R) in ASMCs can relax ASMCs. However, there is a lack of potent TAS2R agonists that can be used in asthma therapies since those tested agonists cannot relax ASMCs at the dose below a few hundred micromolar. Considering that sanguinarine (SA) is a bitter substance often used in small doses for the treatment of asthma in folk medicine, the present study was to determine the rapid relaxation effect of SA on ASMCs and to reveal the underlying mechanisms associated with TAS2R signaling. Here, cell stiffness, traction force, calcium signaling, cAMP levels, and the mRNA expression were evaluated by using optical magnetic twisting cytometry, traction force microscopy, Fluo-4/AM labeling, enzyme-linked immunosorbent assay (ELISA), and quantitative (q)RT-PCR, respectively. We found that 0.5 µM SA immediately decreased cell stiffness and traction force, which is comparable with the effect of 5 µM isoproterenol. In addition, 0.5 µM SA immediately increased intracellular free calcium concentration ([Ca2+]i) and decreased the mRNA expression of contractile proteins such as calponin and α-smooth muscle actin after the treatment for 24 h. Furthermore, SA-mediated decrease in cell stiffness/traction force and increase in [Ca2+]i were significantly blunted by inhibiting the TAS2Rs signaling. These findings establish the rapid relaxation effect of SA at low concentration (<1 µM) on cultured ASMCs depending on TAS2R signaling, indicating that SA might be developed as a useful bronchodilator in asthma therapy.

Toward the Identification of Extra-Oral TAS2R Agonists as Drug Agents for Muscle Relaxation Therapies via Bioinformatics-Aided Screening of Bitter Compounds in Traditional Chinese Medicine.

Significant advances have been made in the past decade in mapping the distributions and the physiological functions of extra-oral bitter taste receptors (TAS2Rs) in non-gustatory tissues. In particular, it has been found that TAS2Rs are expressed in various muscle tissues and activation of TAS2Rs can lead to muscle cell relaxation, which suggests that TAS2Rs may be important new targets in muscle relaxation therapy for various muscle-related diseases. So far, however, there is a lack of potent extra-oral TAS2R agonists that can be used as novel drug agents in muscle relaxation therapies. Interestingly, traditional Chinese medicine (TCM) often characterizes a drug's property in terms of five distinct flavors (bitter, sweet, sour, salty, and pungent) according to its taste and function, and commonly regards "bitterness" as an intrinsic property of "good medicine." In addition, many bitter flavored TCM are known in practice to cause muscle relaxation after long term use, and in lab experiments the compounds identified from some bitter flavored TCM do activate TAS2Rs and thus relax muscle cells. Therefore, it is highly possible to discover very useful extra-oral TAS2R agonists for muscle relaxation therapies among the abundant bitter compounds used in bitter flavored TCM. With this perspective, we reviewed in literature the distribution of TAS2Rs in different muscle systems with a focus on the map of bitter flavored TCM which can regulate muscle contractility and related functional chemical components. We also reviewed the recently established databases of TCM chemical components and the bioinformatics software which can be used for high-throughput screening and data mining of the chemical components associated with bitter flavored TCM. All together, we aim to present a knowledge-based approach and technological platform for identification or discovery of extra-oral TAS2R agonists that can be used as novel drug agents for muscle relaxation therapies through screening and evaluation of chemical compounds used in bitter flavored TCM.

Alopecurone B reverses doxorubicin-resistant human osteosarcoma cell line by inhibiting P-glycoprotein and NF-kappa B signaling.

Doxorubicin (DOX) was first used in osteosarcoma in the early 1970s as a first-line antineoplastic drug. However, the occurrence of drug resistance in chemotherapeutic treatment has greatly restricted its use. When resistance to DOX treatment occurs, osteosarcoma may become not only resistant to the drug originally administered but also to a wide variety of structurally and mechanistically unrelated drugs. Thus, there is an urgent need to find ways of reversing DOX chemotherapy resistance in osteosarcoma. Plant-derived agents have great potential in preventing the onset of the carcinogenic process and enhancing the efficacy of conventional antitumor drugs. Alopecurone B (ALOB), a flavonoid, is isolated from Traditional Chinese Medicine Sophora alopecuroides L., and is reported to have potent inhibitory effect on multidrug resistance associated protein 1. In this study, a DOX-resistant osteosarcoma cell line (MG-63/DOX) was established by increasing the concentration gradient of DOX in a stepwise manner. MTT assay, flow cytometry analysis, dual-luciferase reporter gene assay, quantitative real-time polymerase chain reaction and Western blot analysis were applied to investigate the reversing effect of ALOB and its underlying mechanisms. The results indicated that ALOB mediated the resistance of MG-63/DOX cells to DOX by inhibiting P-glycoprotein function, transcription and expression. Besides, ALOB also enhanced the sensitivity of MG-63/DOX cells to other conventional chemotherapeutic drugs. Cell viability assay confirmed the reversing activity of ALOB. Furthermore, ALOB increased DOX-induced apoptosis at nontoxic concentration. In addition, ALOB showed inhibitory effect on NF-κB transcription in a DOX-independent manner. Furthermore, NF-κB signaling was suppressed by ALOB in an IKK-dependent manner. These studies not only demonstrate that ALOB is a potential agent for reversal of drug resistant cancers, but also testify that ALOB reverses multidrug resistance by inhibiting P-glycoprotein via NF-κB signaling.

Flavonostilbenes from Sophora alopecuroides L. as multidrug resistance associated protein 1 (MRP1) inhibitors.

Flavonoids have always attracted much attention due to their reversal activity on multidrug resistance (MDR). Eight flavonoids isolated from traditional Chinese medicine Sophora alopecuroides L. were applied to test their effect on MDR associated protein 1 (MRP1) through the established predicting assay. Three flavonostilbenes (alopecurone A, B and D) were first found exhibiting potent inhibitory activity on MRP1. All of them dramatically increased 6-carboxyfluorescein diacetate and doxorubicin accumulation in MRP1-transfected U-2 OS cells. The compounds significantly increased the cytotoxicity and decreased the IC50 value of doxorubicin on the MDR cells (12-, 5- and 8-fold, respectively) at a non-toxic concentration (20 µM). Besides, Q-PCR analysis reveals that the MRP1 mRNA level in U-2 OS/MRP1 was also markedly decreased by the three compounds. These findings indicate a new therapeutic role of the herb. The three flavonostilbenes may have the possibility for further development as novel therapeutic reversal agents against MDR.

[Treatment of varicocele infertility men patients of different Chinese medical syndrome types by integrative medicine treatment selection: a primary research].

OBJECTIVE: To explore the optimal treatment selection for treating varicocele (VC) male infertility patients accompanied with oligozoospermia or azoospermia of different Chinese medical syndrome types by comparing the efficacies of integrative medicine. METHODS: One hundred and twenty male infertility patients with VC accompanied with oligozoospermia or azoospermia were assigned to Chinese medical treatment group (A) and the surgical group (B), each consisting of three Chinese medical syndrome types, i.e., damp-heat stagnation syndrome (DHSS), Shen-deficiency blood stasis syndrome (SDBSS), and blood stasis stagnation syndrome (BSSS), 20 in each group. Corresponding Chinese medical treatment was administered to those in Group A, C, and E, while microscopic ligation of internal vena spermatic was administered to those in Group B, D, and F. The routine analysis of semen, biochemical analysis of seminal plasma, and serum sex hormones (prolactin, testosterone, follicle stimulating hormone, luteinizing hormone, and estradiol) were performed before treatment and by the end of the 24th week after treatment. RESULTS: Totally 18 patients' spouses were pregnant. Of them, 1 in Group A of DHSS (abbreviated as Group A), 3 in Group B of DHSS (abbreviated as Group B), 4 in Group A of SDB-SS (abbreviated as Group C), 5 in Group A of SDBSS (abbreviated as Group D), 1 in Group A of BSSS (abbreviated as Group E), and 4 in Group B of BSSS (abbreviated as Group F). After 24-week treatment, the sperm concentration, class a sperm percentage, class a + b sperm percentage, the motility rate, the seminal plasma of fructose density, and the seminal plasma neutral alpha-glucosidase were more significantly improved in Group B, C, D and F, when compared with the same group before treatment (P <0. 01, P <0. 05). There was no statistical difference in the aforesaid indices between before and after treatment in Group A and Group E (P >0.05). As for the improvement percentage of seminal routine indices, the difference of the seminal plasma of fructose density, and the difference of seminal plasma neutral alpha-glucosidase between before and after treatment in the same Chinese medical syndrome types, better effects were obtained in Group B than in Group A (P <0.01), and better effects were obtained in Group F than in Group E (P <0.01). There was no statistical difference between Group C and D (P >0.05). There was no statistical difference in the 5 items of sex hormones in each group between before and after treatment (P >0.05). CONCLUSIONS: Surgical treatment could effectively improve the semen quality for male infertility VC patients accompanied with oligozoospermia or azoospermia. Of them, Chinese medical treatment could be recommended to those of SDBSS who would not receive surgical treatment.