Savoia Carlo P, Liu Qing-Hua, Zheng Yun-Min, Yadav Vishal, Zhang Zhen, Wu Ling-Gang, Wang Yong-Xiao
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York;
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; Institute for Medical Biology, College of Life Sciences, South-Central University for Nationalities, Wuhan, Hubei, China;
Am J Physiol Lung Cell Mol Physiol. 2014 Nov 15;307(10):L781-90. doi: 10.1152/ajplung.00149.2014. Epub 2014 Sep 19.
Local Ca(2+) signals (Ca(2+) sparks) play an important role in multiple cellular functions in airway smooth muscle cells (ASMCs). Protein kinase Cϵ is known to downregulate ASMC Ca(2+) sparks and contraction; however, no complementary phosphatase has been shown to produce opposite effects. Here, we for the first time report that treatment with a specific calcineurin (CaN) autoinhibitory peptide (CAIP) to block CaN activity decreases, whereas application of nickel to activate CaN increases, Ca(2+) sparks in both the presence and absence of extracellular Ca(2+). Treatment with xestospogin-C to eliminate functional inositol 1,4,5-trisphosphate receptors does not prevent CAIP from inhibiting local Ca(2+) signaling. However, high ryanodine treatment almost completely blocks spark formation and prevents the nickel-mediated increase in sparks. Unlike CAIP, the protein phosphatase 2A inhibitor endothall has no effect. Local Ca(2+) signaling is lower in CaN catalytic subunit Aα gene knockout (CaN-Aα(-/-)) mouse ASMCs. The effects of CAIP and nickel are completely lost in CaN-Aα(-/-) ASMCs. Neither CAIP nor nickel produces an effect on Ca(2+) sparks in type 1 ryanodine receptor heterozygous knockout (RyR1(-/+)) mouse ASMCs. However, their effects are not altered in RyR2(-/+) or RyR3(-/-) mouse ASMCs. CaN inhibition decreases methacholine-induced contraction in isolated RyR1(+/+) but not RyR1(-/+) mouse tracheal rings. Supportively, muscarinic contractile responses are also reduced in CaN-Aα(-/+) mouse tracheal rings. Taken together, these results provide novel evidence that CaN regulates ASMC Ca(2+) sparks specifically through RyR1, which plays an important role in the control of Ca(2+) signaling and contraction in ASMCs.
局部钙离子信号(钙离子闪烁)在气道平滑肌细胞(ASMCs)的多种细胞功能中发挥重要作用。已知蛋白激酶Cε可下调ASMCs的钙离子闪烁和收缩;然而,尚未发现有互补的磷酸酶能产生相反的作用。在此,我们首次报道,用特异性钙调神经磷酸酶(CaN)自抑制肽(CAIP)处理以阻断CaN活性会使钙离子闪烁减少,而应用镍激活CaN则会使钙离子闪烁增加,无论细胞外是否存在钙离子。用西托糖苷 - C处理以消除功能性肌醇1,4,5 - 三磷酸受体并不能阻止CAIP抑制局部钙离子信号。然而,高浓度的ryanodine处理几乎完全阻断了闪烁的形成,并阻止了镍介导的闪烁增加。与CAIP不同,蛋白磷酸酶2A抑制剂烯草酮没有作用。在CaN催化亚基Aα基因敲除(CaN - Aα(-/-))小鼠的ASMCs中,局部钙离子信号较低。CAIP和镍的作用在CaN - Aα(-/-)的ASMCs中完全消失。CAIP和镍对1型ryanodine受体杂合敲除(RyR1(-/+))小鼠的ASMCs中的钙离子闪烁均无影响。然而,它们的作用在RyR2(-/+)或RyR3(-/-)小鼠的ASMCs中未改变。CaN抑制可降低离体RyR1(+/+)但不降低RyR1(-/+)小鼠气管环中乙酰甲胆碱诱导的收缩。同样,在CaN - Aα(+/-)小鼠气管环中,毒蕈碱收缩反应也降低。综上所述,这些结果提供了新的证据,表明CaN通过RyR1特异性调节ASMCs的钙离子闪烁,这在ASMCs的钙离子信号控制和收缩中起重要作用。