Novel 1,3,5-triazine-based TRPA1 activators alleviate pro-fibrotic response in human lung fibroblasts

Airway remodeling (AR) is a hallmark of chronic respiratory diseases (CRDs) and involves progressive structural alterations of the airway wall, leading to wall thickening and airway narrowing. Multiple cell types contribute to AR, including lung fibroblasts, which - under the influence of transforming growth factor type β (TGF-β) - upregulate pro-fibrotic markers, undergo phenotypic transition into myofibroblasts, and increase their contractile activity. Current treatment guidelines for CRDs lack effective therapies directly targeting AR. Recent reports suggest that the transient receptor potential ankyrin 1 (TRPA1) ion channel may be implicated in the mechanisms underlying AR. To explore this, we designed and synthesized 1,3,5-triazine-based derivatives (compounds 7 and 8), which exhibit agonistic activity towards TRPA1. In this study, we evaluated their pharmacological activity in TGF-β-stimulated human lung fibroblasts (MRC-5) by assessing calcium influx, pro-fibrotic markers expression, and contractile properties. Both compounds induced a robust calcium influx in MRC-5 cells, while the TRPA1 inhibitors and TGF-β stimulation attenuated this response. The tested 1,3,5-triazine-based TRPA1 activators decreased the expression of selected pro-fibrotic markers, such as α-smooth muscle actin (α-SMA), transgelin and collagen type I, reduced myofibroblasts number, and impaired the contractility of TGF-β-stimulated MRC-5 cells. Notably, the anti-fibrotic effects of the 1,3,5-triazine-based TRPA1 activators exceeded those of ASP-7663, a well-characterized TRPA1 agonist. Our findings expand current knowledge on TRPA1 modulation in AR and provide a novel perspective for drug development in CRDs.