G protein-coupled receptors (GPCR) are a class of receptor superfamily that exist on the surface of cell membrane. With the intensive studies on the GPCR desensitization regulator-β-arrestins, it is found that activated GPCR can not only conduct signal transduction through G protein-dependent pathway, but also mediate via non-G protein-dependent pathway. In addition to mediate endocytosis and desensitization, β-arrestins also initiate a new series of signal transduction events. Therefore, the concept of "biased transduction" was put forward:the receptor activated by a specific ligand could selectively activate a specific signaling pathway, leading the signal to be transmitted downstream along a "preferential" pathway. We call the ligand that binds to the receptor and causes biased activation "biased ligand". It is generally believed that the phenomenon of bias results from different binding modes of ligands and receptors, including multiple receptor conformations, diverse sites that downstream signal proteins bind, and signal proteins' own conformations, etc. Here we give a brief review focusing on the mechanisms of β-arrestin-biased GPCR signal transduction and the advances in the drug development on β-arrestin biased ligands.

Farnesyltransferase (FTase) was selected as a target for virtual screening of inhibitors using the Glide v4.0 program in the Schrödinger software package. We discovered 13 novel structures as farnesyltransferase inhibitors (FTIs) with moderate potency. By analyzing the binding modes of representative compounds 8 (IC₅₀=2.29 μmol·L^-1) and 18 (IC₅₀=0.41 μmol·L^-1) with farnesyltransferase, it was found that compounds 8 and 18 didn't coordinate with Zn²⁺, indicating that the coordination between FTIs with Zn²⁺ is not essential for the bioactivity of the inhibitors. The structure-activity relationship was summarized by analyzing the predicted binding modes of representative compounds. It was found that the scaffolds of the discovered FTIs had room for structural optimization, which lay foundation for obtaining highly active and selective FTIs.

The purpose of this research is to study the anti-atherosclerotic effects and mechanisms of berberine (BBR) in high fat diet (HFD) fed ApoE^-/- mice, and then to lay a solid foundation of the clinical studies of BBR treatment. The hyperlipidemic ApoE^-/- mice model was established by feeding HFD for 12 weeks. Mice were randomly divided into control group (chow diet), model group, BBR group (BBR-L:50 mg·kg^-1, BBR-H:150 mg·kg^-1) and atorvastatin (5 mg·kg^-1) group. Mice were intragastric administration with BBR in 0.5% sodium salt of caboxy methyl cellulose. After 12 weeks, enface aortas were stained with oil red O, and the lesions area were analyzed by Image J software. The inflammatory factor levels were detected by suspension microarray kits. Liver total cholesterol (TC), triglyceride (TG) and free fatty acids (FFA) were determined by commercial kits. Western blot was performed to examine the inflammatory pathway related and cholesterol and lipid transport related proteins' expression. All animal experiments were performed in accordance with the Regulation on the Administration of Laboratory Animals of Institute of Medicinal Biotechnology. After 12 weeks treatment, compared with model group, BBR treatment significantly reduced the lesions area of en face aortas and obviously inhibited serum proinflammatory factors such as IL-1β and IL-6 compared with model group. In addition, BBR treatment obviously reduced liver TC, TG and FFA levels compared with model group. Furthermore, mechanic study showed that BBR significantly inhibited MAPKs and NF-κB pathways, and increased cholesterol and lipid regulated proteins expression such as p-AMPK, LDLR, ABCA1 and SR-BI. In conclusion, BBR can obviously reduce enface aortas lesions in ApoE^-/- mice, which is related to inhibit inflammation and liver cholesterol and lipid accumulation.

Liver fibrosis is a tissue repair compensatory response to liver injury caused by various chronic factors, ultimately leading to liver cirrhosis, liver failure and even hepatocellular carcinoma. Abnormal activation of hepatic stellate cells is the cellular basis of liver fibrosis development. Pepstatin Pr, the derivative of pepstatin A, was isolated from Streptomyces sp. CPCC 202950. Our purpose was to investigate the anti-fibrotic activity of pepstatin Pr and explore its molecular mechanism. Hepatic stellate cell LX-2 was stimulated by TGFβ1 and sub-sequently treated with pepstatin Pr. Its cytotoxicity was detected by sulforhodamine B (SRB) assay. The expression of COL1A1, α-SMA and cathepsin D, signaling proteins TGFβ, Smad and YAP/TAZ were detected by Western blot or real-time PCR. The results showed that pepstatin Pr was not cytotoxic to LX-2 cells. And pepstatin Pr significantly reduced the mRNA and protein expression of COL1A1 and α-SMA, which are important liver fibrosis markers. Pepstatin Pr also repressed the protein expression level of cathepsin D, TGFβ1, YAP/TAZ, the phospholation level of Smad2, and YAP nuclear translocation. In conclusion, pepstatin Pr exhibits anti-fibrotic effects in TGFβ1-stimulaed LX-2 cells by mediating YAP-TGFβ-Smad pathway.

Near-infrared spectroscopy (NIRS) combined with chemometrics can achieve rapid detection in process analysis. After variable selection, the redundant information is effectively removed and the characteristic variables related to the response values are selected. Compared with global model, the complexity is significantly reduced and the prediction accuracy is also improved. In this study, near-infrared spectroscopy analysis combined with different variable selection methods was applied to achieve the rapid detection of baicalin in the extraction process of Scutellaria baicalensis. Data sets were divided based on sample set portioning based on joint x-y distance (SPXY) method. Competitive adaptive weighted resampling method (CARS), random frog (RF) and successive projections algorithm (SPA) were applied to variable selection. Partial least squares (PLS) models were constructed based on above three methods, and the prediction results were compared. After CARS, RF and SPA method, 92, 10 and 17 variables were screened out respectively. According to the performance of the models, CARS method is found to be more effective and suitable than RF and SPA. Furthermore, the characteristic variables selected by CARS method have a better correspondence with the chemical structure of baicalin. The root mean square error (RMSEC) of the calibration set and the root mean square error (RMSEP) of the prediction set are 0.528 2 and 0.720 2 respectively. Compared with the global PLS model, the correlation coefficient of the calibration set (Rc) is increased to 0.979 9 from 0.917 0, and the relative standard errors of prediction (RSEP) is reduced to 5.59% from 10.58%.

Spironolactone, a class Ⅱ drug of the biopharmaceutics classification system, has low oral bioavailability due to poor solubility. Spironolactone solid dispersions were prepared using the solvent method in order to improve its aqueous solubility. Optimization studies of spironolactone solid dispersions were performed using in vitro dissolution tests. Differential scanning calorimetry, X-ray diffraction and Fourier transform infrared were used to investigate the physical state of the drug in carrier materials and to detect the possible interactions between the drug and carrier materials in the solid dispersions. In addition, stress tests were employed to elucidate the key factors which have influence on the stability of the spironolactone solid dispersions. Results showed that spironolactone in the solid dispersions formulated with Soluplus and HPMC-E5 were both in amorphous state and the hydrogen bonds between the drug and carrier materials were formed in the solid dispersion. Therefore, the in vitro dissolution of spironolactone was also significantly enhanced. Stress tests demonstrated that the physical stability of spironolactone solid dispersions prepared with Soluplus was greatly improved compared to those formulated with HPMC-E5. Thus, spironolactone solid dispersion formulated with Soluplus using the solvent method could be used to improve the in vitro dissolution and stability of poorly soluble drugs.

Monoclonal antibodies (mAbs) have been widely used as therapeutic drugs for treating diseases such as cancers and auto-immune diseases. When using an IgG4 isotype, one of the challenges is the instability of its hinge which is prone to Fab-arm exchange (FAE). The hinge sequence of a wild type IgG4 is -CPSC-, however, a single point mutation S228P from -CPSC-to -CPPC-can effectively diminish FAE, thereby improving hinge stability of the IgG4 molecule. Sintilimab is the fully human anti-PD-1 monoclonal antibody designed and developed for immuno-oncology, in which serine 228 in the hinge was engineered to proline to mitigate FAE. In this study, LC-MS is used to study hinge stability of sintilimab in both in vitro (PBS and human serum) and in vivo (SCID mouse) studies. The studies demonstrate that LC-MS is a fast and simple way to monitor for the occurrence of FAE in vitro and in vivo, and FAE can be eliminated by antibody engineering with a single point mutation.

The solubilization and protection of curcumin (Cur) by mixed surfactants were studied through the determination about the critical micellar concentration (CMC) of the mixed surfactants of Tween 80 and dodecyl trimethyl ammonium bromide (DTAB), molar solubilization ratio (MSR), degradation rate (k) of Cur in pH 13 solution and mixed surfactant solutions prepared at pH 13. The results showed that when Tween 80 was used alone, it exhibited high solubilization ability but poor stability. DTAB was used alone, it showed strong stability but poor solubilization ability. When DTAB was mixed with Tween 80 at different mole fractions, the stability of Cur was enhanced, and the best stability was observed when the mole fraction of DTAB was 0.4, although the solubilization ability was not the best at this mole fraction, but MSR was increased by 1.7 times compared to DTAB used alone. Mixed surfactant not only increased the solubility but also improved the stability of Cur. In addition, mixed surfactant has the advantages of less dosage and low toxicity, which is worth popularizing in application.

The aim of this study is to investigate the influence of flufenamic acid (FFA) on the solubility, dissolution and bioavailability of sorafenib (SFN) in the combined administration of the MSNM@SFN and FFA. The MSNM@SFN&FFA was prepared by mixing the MSNM@SFN with FFA. The solubility, dissolution and bioavailability of SFN in the MSNM@SFN&FFA complex was investigated in comparison with those of the MSNM@SFN. This study was performed following the National Institutes of Health guidelines for the use of experimental animals; all care and handling of animals were performed with the approval of the Experimental Animal Center of Peking University Health Science Center. The MSNM@SFN&FFA showed no significant influence on the solubility, dissolution and bioavailability of SFN when compared with the MSNM@SFN. These data indicated that FFA had almost no influence on the solubility, dissolution and bioavailability of SFN in the combined administration of MSNM@SFN and FFA, thus providing an experimental foundation for the subsequent formulation research on the combined usage of drugs.

The aim of this study is to prepare porous γ-cyclodextrin metal-organic framework (CD-MOF) with good biocompatibility to improve the in vitro release properties of water-insoluble drugs. Different sizes of CD-MOF were obtained by controlling the self-assembly of γ-cyclodextrin and potassium ion and the rate of crystal growth. The poorly water-soluble diflunisal (DIF) was selected as the model drug and loaded into the interior of porous CD-MOF by the impregnation method. The DIF loaded CD-MOF (DIF-MOF) was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption and desorption, Fourier infrared spectrometer and thermogravimetric analysis. In addition, in vitro cytotoxicity and solubilizing capability of CD-MOF were investigated. It revealed that the obtained CD-MOF was cubic-like with a narrow size distribution and high porosity. Negligible cytotoxicity was found after incubation with RAW264.7 cells. Compared with the pure CD-MOF carrier, the morphology and crystal form of DIF-MOF was not damaged during the drug loading process. Moreover, the solubility and release rate of water-insoluble DIF from the DIF-MOF were significantly increased.