Li Jie, He Qi, Wang Lingwei, Chen Dandan, Qiu Chen, Xu Peng, Lu Yongzhen, Zeng Yuwei, Chen Rongchang
Key Laboratory of Shenzhen Respiratory Disease, Shenzhen Institute of Respiratory Disease, Shenzhen People's Hospital (The First Affiliated Hospital of Southern University of Science and Technology, The Second Clinical Medical College of Jinan University), Shenzhen, China.
Ann Transl Med. 2021 Apr;9(8):657. doi: 10.21037/atm-21-573.
Dysfunctional phenotype modulation and calcium channels in airway smooth muscle cells (ASMCs) are important characteristics of airway remodeling in chronic asthma. However, the mechanisms underlying these pathological processes remain unclear. SET (I2PP2A, inhibitor-2 of protein phosphatase 2A) has many significant functions and is involved in various physiological and pathological processes. This study aimed to determine the function of SET in chronic asthma.
BALB/c mice were sensitized by ovalbumin injection and repeated inhalation of ovalbumin. The Penh value was measured using the Buxco whole body plethysmography system. A short hairpin RNA of the SET gene was designed and transfected into ASMCs derived from asthmatic mice. Flow cytometry of Annexin-V/propidium iodide staining was used for evaluating cell apoptosis. Western blot was adopted to measure the expression levels of ASMCs phenotype modulation markers and calcium channel-associated proteins.
The results showed that shRNA targeting SET significantly decreased the expression of SET, and enhanced the apoptosis of ASMCs. SET knockdown promoted the expression of contractile phenotype markers such as α-SMA (alpha smooth muscle Actin), SM-MHC (smooth muscle Myosin heavy chain), and calponin, and inhibited the expression of synthetic phenotype markers including vimentin and CD44. The expression of the calcium channel-related proteins STIM1 (Stromal interaction molecule 1) and Orai1 were also inhibited after SET knockdown.
These data demonstrated that SET participated in the development of airway dysfunction in asthma, suggesting that the silencing of SET may be a new therapeutic target for the treatment of asthma patients.
气道平滑肌细胞（ASMCs）的功能失调表型调节和钙通道是慢性哮喘气道重塑的重要特征。然而，这些病理过程的潜在机制仍不清楚。SET（I2PP2A，蛋白磷酸酶2A的抑制剂-2）具有许多重要功能，并参与各种生理和病理过程。本研究旨在确定SET在慢性哮喘中的作用。
通过注射卵清蛋白并反复吸入卵清蛋白使BALB/c小鼠致敏。使用Buxco全身体积描记系统测量Penh值。设计SET基因的短发夹RNA并将其转染到哮喘小鼠来源的ASMCs中。采用Annexin-V/碘化丙啶染色的流式细胞术评估细胞凋亡。采用蛋白质印迹法检测ASMCs表型调节标志物和钙通道相关蛋白的表达水平。
结果显示，靶向SET的shRNA显著降低了SET的表达，并增强了ASMCs的凋亡。敲低SET促进了收缩型表型标志物如α-SMA（α平滑肌肌动蛋白）、SM-MHC（平滑肌肌球蛋白重链）和钙调蛋白的表达，并抑制了包括波形蛋白和CD44在内的合成型表型标志物的表达。敲低SET后，钙通道相关蛋白STIM1（基质相互作用分子1）和Orai1的表达也受到抑制。
这些数据表明SET参与了哮喘气道功能障碍的发生发展，提示沉默SET可能是治疗哮喘患者的新治疗靶点。
