Diminished sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) expression contributes to airway remodelling in bronchial asthma
Diminished sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) expression contributes to airway remodelling in bronchial asthma
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DOI：
10.1073/pnas.0902295106
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发表时间：
2009-06-30
影响因子：
11.1
通讯作者：
Lee, Tak H.
中科院分区：
文献类型：
--
作者：
Mahn, Katharina;Hirst, Stuart J.;Lee, Tak H.
气道平滑肌（ASM）的表型调节是哮喘气道重塑的重要特征，其特征在于促炎趋化因子的增殖和分泌增强。这些活动受胞质中游离Ca 2+浓度（[Ca 2 +]（i））的调节。[Ca 2 +]（i）的升高通过肌浆网/内质网Ca 2+（SERCA）泵将Ca 2+快速再摄取到肌浆网（SR）储存中而正常化。我们研究了哮喘患者ASM增殖和分泌反应的增加是否是由于SERCA表达减少所致。ASM细胞从患有和不患有哮喘的受试者中培养。免疫印迹、免疫组化和实时荧光PCR检测SERCA表达。测量[Ca 2 +]（i）、细胞铺展、细胞增殖和嗜酸性粒细胞趋化因子-1释放的变化。与来自健康受试者的对照细胞相比，来自中重度哮喘受试者的ASM细胞中SERCA 2 mRNA和蛋白表达降低。在患有中度/重度哮喘的受试者中，体内ASM中SERCA 2表达类似地降低。在哮喘患者的ASM细胞中，细胞表面受体诱导的SR激活或SERCA介导的Ca 2+再摄取抑制后[Ca 2 +]（i）的升高减弱。同样，在哮喘患者的ASM细胞中，缓激肽刺激后[Ca]（i）恢复到基线水平的时间延迟了约50%。siRNA介导的来自健康受试者的ASM中SERCA 2的敲低增加了细胞铺展、eotaxin-1释放和增殖。我们的研究结果表明，在哮喘的ASM中SERCA 2的缺陷，有助于其分泌和过度增殖的表型在哮喘，这可能在气道重塑的机制中发挥关键作用。
Phenotypic modulation of airway smooth muscle (ASM) is an important feature of airway remodeling in asthma that is characterized by enhanced proliferation and secretion of pro-inflammatory chemokines. These activities are regulated by the concentration of free Ca2+ in the cytosol ([Ca2+](i)). A rise in [Ca2+](i) is normalized by rapid reuptake of Ca2+ into sarcoplasmic reticulum (SR) stores by the sarco/endoplasmic reticulum Ca2+ (SERCA) pump. We examined whether increased proliferative and secretory responses of ASM from asthmatics result from reduced SERCA expression. ASM cells were cultured from subjects with and without asthma. SERCA expression was evaluated by western blot, immunohistochemistry and real-time PCR. Changes in [Ca2+](i), cell spreading, cellular proliferation, and eotaxin-1 release were measured. Compared with control cells from healthy subjects, SERCA2 mRNA and protein expression was reduced in ASM cells from subjects with moderately severe asthma. SERCA2 expression was similarly reduced in ASM in vivo in subjects with moderate/severe asthma. Rises in [Ca2+](i) following cell surface receptor-induced SR activation, or inhibition of SERCA-mediated Ca2+ re-uptake, were attenuated in ASM cells from asthmatics. Likewise, the return to baseline of [Ca](i) after stimulation by bradykinin was delayed by approximately 50% in ASM cells from asthmatics. siRNA-mediated knockdown of SERCA2 in ASM from healthy subjects increased cell spreading, eotaxin-1 release and proliferation. Our findings implicate a deficiency in SERCA2 in ASM in asthma that contributes to its secretory and hyperproliferative phenotype in asthma, and which may play a key role in mechanisms of airway remodeling.