Transient Receptor Potential Ankyrin 1 Channel Alters Transforming Growth Factor Beta 1/Smad Signaling in Rat Vocal Fold Fibroblasts

Objectives Vocal fold scar remains a therapeutic challenge. Vocal fold fibroblasts (VFFs) secrete extracellular matrix (ECM), and transforming growth factor‐beta 1 (TGF‐β1)‐mediated fibroblast to myofibroblast differentiation is central to the development of fibrosis. The transient receptor potential (TRP) channel superfamily is a group of nonselective cation channels, and activation of TRP ankyrin 1 (TRPA1) channel has been shown to have antifibrotic effects through TGF‐β1/Smad signaling in various organs. This study aimed to elucidate expression of TRPA1 and the impact of TRPA1 activation on TGF‐β1/Smad signaling in VFFs. Methods Vocal folds were dissected from 10‐week‐old, male Sprague‐Dawley rats and primary VFFs were established. TRPA1 was examined in VFFs and lamina propria via immunostaining. VFFs were treated with allyl isothiocyanate (AITC, TRP channel agonist, 10 −5 M) ± TGF‐β1 (10 ng/ml) ± A‐967079 (selective TRPA1 channel antagonist, 5.0 × 10 −7 M) for 4 or 24 h. Trpa1 , Smad3 , Smad7 , Col1a1 , Acta2 , and Has1 mRNA expression were quantified via qPCR. Results TRPA1 was expressed in cultured VFFs and the lamina propria. TGF‐β1 administration significantly increased Trpa1 compared to control. AITC alone did not alter Smad3 , Smad7 , Acta2 , or ECM related genes. However, the combination of AITC and TGF‐β1 significantly increased Smad3 and decreased Smad7 and Acta2 compared to TGF‐β1 alone; A‐967079 significantly reduced this response. Conclusions VFFs expressed TRPA1, and the activation of TRPA1 regulated TGF‐β1/Smad signaling in VFFs. These findings provide preliminary insights into potential anti‐fibrotic mechanisms of TRPA1 activation through TGF‐β1/Smad signaling in VFFs. Level of Evidence NA Laryngoscope , 2024