Baarsma Hoeke A, Han Bing, Poppinga Wilfred J, Driessen Saskia, Elzinga Carolina R S, Halayko Andrew J, Meurs Herman, Maarsingh Harm, Schmidt Martina
Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands.
Groningen Research Institute for Asthma and COPD, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
Front Cell Dev Biol. 2020 Apr 9;8:165. doi: 10.3389/fcell.2020.00165. eCollection 2020.
With the ability to switch between proliferative and contractile phenotype, airway smooth muscle (ASM) cells can contribute to the progression of airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), in which airway obstruction is associated with ASM hypertrophy and hypercontractility. A-kinase anchoring proteins (AKAPs) have emerged as important regulatory molecules in various tissues, including ASM cells. AKAPs can anchor the regulatory subunits of protein kinase A (PKA), and guide cellular localization via various targeting domains. Here we investigated whether disruption of the AKAP-PKA interaction, by the cell permeable peptide stearated (st)-Ht31, alters human ASM proliferation and contractility. Treatment of human ASM with st-Ht31 enhanced the expression of protein markers associated with cell proliferation in both cultured cells and intact tissue, although this was not accompanied by an increase in cell viability or cell-cycle progression, suggesting that disruption of AKAP-PKA interaction on its own is not sufficient to drive ASM cell proliferation. Strikingly, st-Ht31 enhanced contractile force generation in human ASM tissue with concomitant upregulation of the contractile protein α-sm-actin. This upregulation of α-sm-actin was independent of mRNA stability, transcription or translation, but was dependent on proteasome function, as the proteasome inhibitor MG-132 prevented the st-Ht31 effect. Collectively, the AKAP-PKA interaction appears to regulate markers of the multi-functional capabilities of ASM, and this alter the physiological function, such as contractility, suggesting potential to contribute to the pathophysiology of airway diseases.
气道平滑肌（ASM）细胞具有在增殖和收缩表型之间转换的能力，可促使哮喘和慢性阻塞性肺疾病（COPD）等气道疾病的进展，在这些疾病中，气道阻塞与ASM肥大和高反应性相关。A激酶锚定蛋白（AKAPs）已成为包括ASM细胞在内的各种组织中的重要调节分子。AKAPs可锚定蛋白激酶A（PKA）的调节亚基，并通过各种靶向结构域引导细胞定位。在此，我们研究了细胞可渗透肽硬脂酸化（st）-Ht31破坏AKAP-PKA相互作用是否会改变人ASM的增殖和收缩性。用st-Ht31处理人ASM可增强培养细胞和完整组织中与细胞增殖相关的蛋白标志物的表达，尽管这并未伴随着细胞活力或细胞周期进程的增加，这表明单独破坏AKAP-PKA相互作用不足以驱动ASM细胞增殖。令人惊讶的是，st-Ht31增强了人ASM组织中的收缩力生成，并伴随收缩蛋白α-平滑肌肌动蛋白（α-sm-actin）的上调。α-sm-actin的这种上调与mRNA稳定性、转录或翻译无关，但依赖于蛋白酶体功能，因为蛋白酶体抑制剂MG-132可阻止st-Ht31的作用。总体而言，AKAP-PKA相互作用似乎调节ASM多功能能力的标志物，并改变其生理功能，如收缩性，提示其可能参与气道疾病的病理生理学过程。
