Discovery of zolinium TSG1180 as a novel agonist of transgelin-2 for treating asthma.

Asthma is a complex and heterogeneous respiratory disease that causes serious social and economic burdens. Current drugs such as ß2-agonists cannot fully control asthma. Our previous study found that Transgelin-2 is a potential target for treating asthmatic pulmonary resistance. Herein, we discovered a zolinium compound, TSG1180, that showed a strong interaction with Transgelin-2. The equilibrium dissociation constants (KD) of TSG1180 to Transgelin-2 were determined to be 5.363 × 10-6 and 9.81 × 10-6 M by surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Cellular thermal shift assay (CETSA) results showed that the thermal stability of Transgelin-2 increased after coincubation of TSG1180 with lysates of airway smooth muscle cells (ASMCs). Molecular docking showed that Arg39 may be the key residue for the binding. Then, the SPR result showed that the binding affinity of TSG1180 to Transgelin-2 mutant (R39E) was decreased by 1.69-fold. Real time cell analysis (RTCA) showed that TSG1180 treatment could relax ASMCs by 19 % (P < 0.05). Once Transgelin-2 was inhibited, TSG1180 cannot induce a relaxation effect, suggesting that the relaxation effect was specifically mediated by Transgelin-2. In vivo study showed TSG1180 effectively reduced pulmonary resistance by 64 % in methacholine-induced mice model (P < 0.05). Furthermore, the phosphorylation of Ezrin at T567 was increased by 8.06-fold, the phosphorylation of ROCK at Y722 was reduced by 38 % and the phosphorylation of RhoA at S188 was increased by 52 % after TSG1180 treatment. These results suggested that TSG1180 could be a Transgelin-2 agonist for further optimization and development as an anti-asthma drug.

The Effects of a Transgelin-2 Agonist Administered at Different Times in a Mouse Model of Airway Hyperresponsiveness.

Airway hyperresponsiveness (AHR) is one of the most important features of asthma. Our previous study showed that inhaled transgelin-2 agonist, TSG12, effectively reduced pulmonary resistance in a mouse model of asthma in a dose-dependent manner. However, the optimal administration time of TSG12 to reduce AHR and the pharmacological effects are still unclear. In this study, the effects of TSG12 inhalation before and during AHR occurrence were examined. The results showed that the pulmonary resistance was reduced by 57% and the dynamic compliance was increased by 46% in the TSG12 Mch group (atomize TSG12 10 min before methacholine, p < 0.05 vs. model). The pulmonary resistance was reduced by 61% and the dynamic compliance was increased by 47% in the TSG12 + Mch group (atomize TSG12 and methacholine together, p < 0.05 vs. model). Quantitative real-time PCR showed that the gene expression levels of transgelin-2, myosin phosphatase target subunit-1, and myosin light chain were up-regulated by 6.4-, 1.9-, and 2.8-fold, respectively, in the TSG12 Mch group. The gene expression levels of transgelin-2, myosin phosphatase target subunit-1, and myosin light chain were up-regulated by 3.2-, 1.4-, and 1.9-fold, respectively, in the TSG12 + Mch group. The results suggested that TSG12 effectively reduces pulmonary resistance when TSG12 inhalation occurred both before and during AHR occurrence. Gene expression levels of transgelin-2 and myosin light chain were significantly up-regulated when TSG12 inhalation occurred before AHR occurrence. This study may provide a basis for the administration time of TSG12 for asthma treatment in the future.