CST1promotes the proliferation and migration of PDGF‐BB‐treated airway smooth muscle cells via the PI3K/AKTsignaling pathway

Typically, airway remodeling caused by migration and proliferation of airway smooth muscle cells (ASMCs) plays a crucial role in the pathophysiological characteristics of asthma development. Cystatin 1 (CST1), a protein‐coding gene referred to as Cystatin SN, is highly expressed in asthma patients. However, the role of CST1 and related molecular mechanisms in the development of asthma remains to be explored. This study aims to investigate the role of CST1 in asthma progression and present related molecular mechanisms. To explore these aspects, human ASMCs with platelet‐derived growth factor BB (PDGF‐BB) are initially stimulated and applied as a cellular model of asthma. Further, CST1 is knocked down with small interfering ribose nucleic acid (siRNA) overexpressed with plasmids. Then, 5‐ethynyl‐2′‐deoxyuridine (EdU) and Cell Count Kit (CCK)‐8 assays are applied to assess the cell proliferation rates. Further, Transwell and Western blot analyses for migration of cells and expression of MMP1 and MMP9 proteins are assessed, respectively. Under PDGF‐BB stimulation, human ASMCs showed an increased CST1 expression, enhanced proliferation, and migration abilities, as well as up‐regulated PI3K/AKT signaling pathway. Further, knockdown or overexpression of CST1 presented the declined or enhanced proliferation, migration, and up‐regulation of the PI3K/AKT signaling pathway of human ASMCs. Inhibiting PI3K/AKT signaling pathway displayed the reduced migration and proliferation of human ASMCs. In summary, these findings indicated that CST1 played an essential role in the progression of asthma by activating the PI3K/AKT signaling pathway and promoting the migration and proliferation abilities of human ASMCs treated with PDGF‐BB.