Abstract

Celastrol attenuates steroid-resistant airway remodeling. • Celastrol restores AMOTL1 expression in SSRA mouse lungs. • AMOTL1 mediates celastrol-induced Hippo/YAP regulation. • CTGF/CYR61 mediate YAP/TAZ-driven HBSMC remodeling. • Airway-local Amotl1 knockdown weakens celastrol protection. Background Severe steroid-resistant asthma (SSRA) is frequently associated with irreversible airway remodeling (AR), which contributes to persistent airflow limitation and poor therapeutic responsiveness. Celastrol (CEL) exhibits anti-inflammatory and tissue-protective properties; however, its role in steroid-resistant AR remains unclear. Purpose This study aimed to evaluate the therapeutic effects of CEL on SSRA and to determine whether AMOTL1-dependent Hippo/Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) signaling contributes to its anti-remodeling activity. Methods SSRA mice were generated via OVA/CFA/LPS sensitization and challenge and treated with CEL or dexamethasone. Airway hyperresponsiveness (AHR), lung histopathology, inflammatory cell infiltration, mucus secretion, collagen deposition, and lung proteomic profiles were evaluated. Osteopontin (OPN)-stimulated human bronchial smooth muscle cells (HBSMCs) were used to model airway smooth muscle remodeling. AMOTL1 gain- and loss-of-function studies were conducted in HBSMCs, and airway-local Amotl1 knockdown was introduced into SSRA mice. Results CEL improved AHR and suppressed airway inflammation, mucus production, and collagen accumulation in SSRA mice. Proteomic analysis revealed that AMOTL1 was downregulated in SSRA and restored by CEL treatment. In HBSMCs, CEL suppressed OPN-induced proliferation, migration, and extracellular matrix production, accompanied by Hippo pathway reactivation and YAP/TAZ inhibition. AMOTL1 knockdown in HBSMCs attenuated these anti-remodeling effects, whereas AMOTL1 overexpression recapitulated the protective effects of CEL. In vivo, Amotl1 knockdown bl