A comparative molecular field analysis and molecular modelling studies on pyridylimidazole type of angiotensin II antagonists

Development and validation of a liquid chromatography-tandem mass spectrometry method for pharmacokinetic study of TM-53, a novel transcriptional coactivator with PDZ-binding motif (TAZ) modulator

Transcriptional coactivator with PDZ-binding motif (TAZ) is considered an attractive target for osteoporosis, obesity, and muscle regeneration. TM-53, a promising TAZ modulator, was recently introduced, and here, we developed a rapid, precise, and reliable analytical method for TM-53 and characterized its pharmacokinetic properties in rat plasma. The hybrid triple quadrupole/linear ion trap coupled to liquid chromatography method was developed and validated to quantify TM-53. Additionally, TM-53 concentrations in plasma were analyzed, and its pharmacokinetic parameters were calculated by non-compartmental analysis. Multiple reaction monitoring at m/z 569.4→207.1 showed the most sensitive signals for TM-53, and the linear scope of the standard curve was between 1.5ng/mL and 500ng/mL. The intra- and inter-day precisions of the quality control samples were <15%, and their accuracies were ranged from 86.2% to 111.0%. Furthermore, the matrix effects, extraction recoveries, and process efficiencies of this analytical method for evaluating TM-53 in rat plasma were 99.1%, 99.9%, and 99.1% respectively. In short- and long-term stability studies, TM-53 showed good stability under frozen conditions, but TM-53 hydrolysis in the plasma matrix was observed following storage at room temperature. This analytical method was successfully applied for pharmacokinetic analysis of TM-53 in rat plasma and demonstrated excellent sensitivity, selectivity, precision, and accuracy. These data indicated that this method can be applied for further preclinical studies of TM-53.

TM-25659 enhances osteogenic differentiation and suppresses adipogenic differentiation by modulating the transcriptional co-activator TAZ

BACKGROUND AND PURPOSE

The transcriptional co-activator with PDZ-binding motif (TAZ) is characterized as a transcriptional modulator of mesenchymal stem cell differentiation into osteoblasts and adipocytes. Moreover, increased TAZ activity in the nucleus enhances osteoblast differentiation and suppresses adipocyte development by interacting with runt-related transcription factor 2 (RUNX2) and PPARγ, respectively. Therefore, it would be of interest to identify low MW compounds that modulate nuclear TAZ activity.

EXPERIMENTAL APPROACH

High-throughput screening was performed using a library of low MW compounds in order to identify TAZ modulators that enhance nuclear TAZ localization. The effects and molecular mechanisms of a TAZ modulator have been characterized in osteoblast and adipocyte differentiation.

KEY RESULTS

We identified 2-butyl-5-methyl-6-(pyridine-3-yl)-3-[2'-(1H-tetrazole-5-yl)-biphenyl-4-ylmethyl]-3H-imidazo[4,5-b]pyridine] (TM-25659) as a TAZ modulator. TM-25659 enhanced nuclear TAZ localization in a dose-dependent manner and attenuated PPARγ-mediated adipocyte differentiation by facilitating PPARγ suppression activity of TAZ. In addition, TAZ-induced RUNX2 activity activation was further increased in osteoblasts, causing increased osteoblast differentiation. Accordingly, TM-25659 suppressed bone loss in vivo and decreased weight gain in an obesity model. After oral administration, TM-25659 had a favourable pharmacokinetic profile.

CONCLUSION AND IMPLICATIONS

TM-25659 stimulated nuclear TAZ localization and thus caused TAZ to suppress PPARγ-dependent adipogenesis and enhance RUNX2-induced osteoblast differentiation in vitro and in vivo. Our data suggest that TM-25659 could be beneficial in the control of obesity and bone loss.

AT1 Receptor Ligands: Virtual-Screening-Based Design with TOPP Descriptors, Synthesis, and Biological Evaluation of Pyrrolidine Derivatives

As a continuing effort to establish the structure-activity relationships (SARs) within the series of the angiotensin II antagonists (sartans), a pharmacophoric model was built by using novel TOPP 3D descriptors. Statistical values were satisfactory (PC4: r(2)=0.96, q(2) ((5) (random) (groups))=0.84; SDEP=0.26) and encouraged the synthesis and consequent biological evaluation of a series of new pyrrolidine derivatives. SAR together with a combined 3D quantitative SAR and high-throughput virtual screening showed that the newly synthesized 1-acyl-N-(biphenyl-4-ylmethyl)pyrrolidine-2-carboxamides may represent an interesting starting point for the design of new antihypertensive agents. In particular, biological tests performed on CHO-hAT(1) cells stably expressing the human AT(1) receptor showed that the length of the acyl chain is crucial for the receptor interaction and that the valeric chain is the optimal one.

QSAR study of angiotensin II antagonists using robust boosting partial least squares regression

In the current study, robust boosting partial least squares (RBPLS) regression has been proposed to model the activities of a series of 4H-1,2,4-triazoles as angiotensin II antagonists. RBPLS works by sequentially employing PLS method to the robustly reweighted versions of the training compounds, and then combing these resulting predictors through weighted median. In PLS modeling, an F-statistic has been introduced to automatically determine the number of PLS components. The results obtained by RBPLS have been compared to those by boosting partial least squares (BPLS) repression and partial least squares (PLS) regression, showing the good performance of RBPLS in improving the QSAR modeling. In addition, the interaction of angiotensin II antagonists is a complex one, including topological, spatial, thermodynamic and electronic effects.

3-D QSAR studies of triazolinone based balanced AT1/AT2 receptor antagonists

Essential structural and physicochemical requirements in terms of common biophoric sites (pharmacophore) and secondary sites for binding and interacting with AT1 and AT2 receptors have been identified using APEX-3-D expert system on 16 N2- aryl triazolinone biphenyl sulphonamides. Among several biophoric 3-D QSAR models two models (Nos. 1 and 2) having R2 > 0.7, chance <0.05 and match >0.5 and two models (Nos. 3 and 4) having R2 > 0.89, chance <0.03 and match >0.5 with three biophoric sites and two secondary sites (except model No. 4 with three secondary sites) describe the variation in AT1 and AT2 antagonistic activities, respectively.