Calcium-pH crosstalks in rat mast cells: modulation by transduction signals show non-essential role for calcium in alkaline-induced exocytosis
Calcium-pH crosstalks in rat mast cells: modulation by transduction signals show non-essential role for calcium in alkaline-induced exocytosis
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DOI：
10.1016/j.bcp.2004.10.001
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发表时间：
2005-01-15
影响因子：
5.8
通讯作者：
Botana, LM
中科院分区：
文献类型：
--
作者：
Alfonso, A;Vieytes, MR;Botana, LM
据报道，用氯化铵（NH 4Cl）碱化细胞溶质pH是肥大细胞脱粒的刺激。本文研究了蛋白激酶C（PKC）、环磷酸腺苷（cAMP）、酪氨酸激酶（TyrK）和磷脂酰肌醇3-激酶（PI（3）K）等靶向药物对这种作用的调节作用。我们使用Go 6976（100 nM）和低浓度的GF 109203 X（Gf）（50 nM）来抑制钙依赖性PKC同工酶。对于钙非依赖性同工酶，我们使用500 nM Gf和10 μ M rottlerin特异性抑制PKC 8，白屈菜红碱作为非特异性PKC抑制剂。染料木黄酮（10 μ M）和lavelustin A（1 μ M）用作非特异性TyrK抑制剂，10 nM渥曼青霉素用作PI 3 K抑制剂。白屈菜红碱和50 nM Gf抑制组胺释放存在的外部钙。渥曼青霉素的抑制作用是严格的内钙依赖性的。cAMP活性药物不改变对NH 4Cl的反应。NH 4Cl对组胺释放的影响是由细胞溶质pH的瞬时升高引发的，这与细胞溶质钙的升高同时发生，随后在加入外部钙后可能发生Ca 2 +-H+交换。EGTA抑制了次适浓度NH_4Cl的反应，而BAPTA增强了NH_4Cl的作用。NH 4Cl介导的钙释放和组胺释放之间存在明确的关系，因为抑制这种释放的药物也抑制NH 4Cl介导的组胺释放;然而，在没有任何钙释放的情况下，NH 4Cl介导的组胺释放是可能的，如BAPTA所示。结合PKC抑制剂的结果，该数据表明钙不仅对触发细胞活化是不必要的，而且它可能是NH 4Cl介导的胞吐作用的负调节剂。(C)2004年爱思唯尔公司All rights reserved.
Alkalinization of cytosolic pH with ammonium chloride (NH4Cl) was reported to be a stimulus for mast cell degranulation. This paper studied the modulatory role of drugs that target protein kinase C (PKC), adenosine 3,5'-cyclic monophosphate (cAMP), tyrosine kinase (TyrK) and phosphatidylinositol 3-kinase (Pl(3)K) on this effect. We used Go6976 (100 nM) and low concentrations of GF109203X (Gf) (50 nM) to inhibit calcium-dependent PKC isozymes. For calcium-independent isozymes, we used 500 nM Gf, and 10 muM rottlerin to specifically inhibit PKC 8, and chelerythrine as non-specific PKC inhibitor. Genistein (10 muM) and lavendustin A (1 muM) were used as unspecific TyrK inhibitors, and 10 nM wortmannin as a PI3K inhibitor. Chelerythrine and 50 nM Gf inhibit histamine release in the presence of external calcium. The inhibition caused by wortmannin was strictly internal calcium-dependent. cAMP-active drugs did not modify the response to NH4Cl. The effect of NH4Cl on histamine release was triggered by a transient elevation on cytosolic pH, which was simultaneous to an elevation on cytosolic calcium and followed by a probable Ca2+-H+ exchange after addition of external calcium. EGTA inhibit the response to suboptimal concentrations of NH4Cl, and BAPTA increased the effect of NH4Cl. There is a clear relationship between NH4Cl-mediated calcium release and histamine release, since those drugs that inhibit this release also inhibit NH4Cl-mediated histamine release; nevertheless, NH4Cl-mediated histamine release was possible in the absence of any calcium release, as shown with BAPTA. This data, in combination with the results with PKC inhibitors, suggest that calcium is not only unnecessary to trigger cell activation, but also that it may be a negative modulator of NH4Cl-mediated exocytosis.(C) 2004 Elsevier Inc. All rights reserved.