Abstract Rationale Lung fibroblasts (FBs) play a pivotal role in airway remodeling in asthma. During profibrotic and inflammatory conditions, FB undergoes myofibroblast differentiation, which contributes to airway wall thickening, stiffness, and airflow obstruction. Myofibroblast differentiation is a process in which fibroblasts transform into highly contractile fibers in response to profibrotic mediators such as transforming growth factor-beta 1 (TGF-β1). This transition is characterized by increased production of alpha-smooth muscle actin (α-SMA), and the formation of actin stress fibers, which are crucial for contractile machinery. Our previous findings identified the important role of Kisspeptin/KISS1R (Kp/KISS1R) in airway smooth muscle remodeling. However, there is no information about the expression and function of Kp/KISS1R in the lung FB. This study investigates the expression of Kp/KISS1R in lung FB and their role in myofibroblast transition. Methods Primary human lung FBs were isolated from surgical lung resections (Mayo IRB-approved) and cultured in DMEM-high glucose medium with 10% fetal bovine serum and 1% antibiotic/antimycotic. Upon reaching ∼90% confluence, cells were serum-deprived and treated with kisspeptin-10 (Kp-10, 1 µM) in the presence or absence of TGF-β1 (10 ng/mL). Expression of Kisspeptin, KISS1R and α-SMA in FB cells were assessed by western blotting and confocal microscopy. FB filamentous (F)-actin formation was analyzed by staining with phalloidin. In addition, collagen gel contraction assays were performed to study fibroblast contractility. Results We found the ubiquitous expression of kisspeptin and KISS1R in human FB. Notably, we observed that KISS1R expression was significantly reduced in asthmatic FB compared to non-asthmatic FB cells. Consistent with this observation, exposure of profibrotic mediator TGF-β1 effectively reduced the expression of KISS1R in non-asthmatic FB. Furthermore, TGF-β1 exposure significantly increased the α-SMA expression in human FB cells, a myofibroblast marker. Treatment with Kp-10 significantly reduced TGF-β1-induced α-SMA expression in FB cells. TGF-β1 stimulation in human FB increased the F-actin formation. Kp-10 significantly attenuated TGF-β1-induced F-actin formation in FB cells. Additionally, chronic TGF-β1 exposure enhanced collagen gel contraction by FBs, while Kp-10 treatment effectively reduced this contraction. Conclusion This study demonstrates that activation of Kp/KISS1R signaling attenuates TGF-β1-induced myofibroblast differentiation in lung FB, suggesting KISS1R as a potential therapeutic target against airway remodeling. This abstract is funded by: NIH grant R01-HL146705 (Venkatachalem)
Rajarajan et al. (Fri,) studied this question.