A novel pathway for the activation of phospholipase D by P2z purinergic receptors in BAC1.2F5 macrophages.
A novel pathway for the activation of phospholipase D by P2z purinergic receptors in BAC1.2F5 macrophages.
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DOI：
10.1016/s0021-9258(18)35890-3
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发表时间：
1992-11
期刊：
影响因子：
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通讯作者：
C. El-Moatassim;G. Dubyak
中科院分区：
文献类型：
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作者：
C. El-Moatassim;G. Dubyak
巨噬细胞表达两种不同类型的细胞外ATP的核苷酸（P2嘌呤能）受体：一种类型通过激活磷脂酰肌醇磷脂酶C（PI-PLC）诱导Ca（2+）动员反应，而第二种类型诱导非选择性孔的快速形成，这些孔被离子和小（< 1 kDa）有机分子渗透。我们已经证实了这两种ATP受体类型在BAC 1.2F5鼠巨噬细胞系中的存在，并且已经鉴定了3 '-O-（4-苯甲酰基）苯甲酰基-ATP（BzATP）作为所谓的P2 z或成孔ATP受体类型的选择性和有效的激动剂。一些证据表明，这些P2 z受体的占用也伴随着磷脂酰胆碱选择性磷脂酶D（PLD）效应酶活性的快速和大幅增加。在细胞代谢标记的[3 H]油酸或[3 H]甘油和刺激的存在下，乙醇，ATP和BzATP诱导的[3 H]磷脂酰乙醇（PEt）积累的速度和程度增加了几倍。这些反应仅由ATP、BzATP和ATP γ S（腺苷5 '-O-（3-硫代三磷酸）刺激，效力的等级顺序为：BzATP > ATP > ATP γ A;对其他腺嘌呤核苷酸或非腺嘌呤核苷酸没有反应。值得注意的是，P2 z受体激动剂刺激PLD活性的能力不依赖于细胞外[Ca 2 +]或胞浆[Ca 2 +]升高的存在。离子霉素、短杆菌肽、毛地黄皂苷、UTP、血小板激活因子或佛波酯不能定量模拟这些核苷酸的作用，这表明P2 z受体激动剂激活PLD不是继发性反应，原因是：1）增加Ca 2+内流; 2）膜去极化; 3）质膜非选择性透化; 4）刺激Ca（2+）动员ATP受体; 5）主要PI-PLC途径的刺激;或6）蛋白激酶C的活化。这些研究结果表明，激活一种新的PLD为基础的信号通路可能发挥重要作用，在巨噬细胞功能的调制孔形成P2 z受体的细胞外ATP。
Macrophages express two distinct types of nucleotide (P2 purinergic) receptors for extracellular ATP: one type induces a Ca(2+)-mobilizing response via the activation of phosphatidylinositol-phospholipase C (PI-PLC) while the second type induces the rapid formation of nonselective pores which are permeated by ions and small (< 1 kDa) organic molecules. We have confirmed the presence of these two ATP receptor types in the BAC1.2F5 murine macrophage cell line and have identified 3‘-O-(4-benzoyl)benzoyl-ATP (BzATP) as a selective and potent agonist for the so-called P2z or pore-forming ATP receptor type. Several lines of evidence indicated that occupation of these P2z receptors is also accompanied by a rapid and large increase in the activity of a phosphatidylcholine-selective phospholipase D (PLD) effector enzyme. In cells metabolically labeled with [3H]oleic acid or [3H]glycerol and stimulated in the presence of ethanol, ATP and BzATP induced a severalfold increase in the rate and extent of [3H]phosphatidylethanol (PEt) accumulation. These responses were stimulated only by ATP, BzATP, and ATP gamma S (adenosine 5‘-O-(3-thiotriphosphate) with the rank order of potency: BzATP > ATP > ATP gamma A; there was no response to other adenine nucleotides or to non-adenine nucleotides. Significantly, the ability of P2z receptor agonists to stimulate this PLD activity was not dependent on the presence of extracellular [Ca2+] or elevation of cytosolic [Ca2+]. The inability of ionomycin, gramicidin, digitonin, UTP, platelet-activating factor, or phorbol ester to quantitatively mimic these nucleotide effects suggested that activation of this PLD by P2z receptor agonists was not a secondary response due to: 1) enhanced Ca2+ influx; 2) membrane depolarization; 3) nonselective permeabilization of the plasma membrane; 4) stimulation of Ca(2+)-mobilizing ATP receptors; 5) stimulation of a primary PI-PLC pathway; or 6) activation of protein kinase C. These findings suggest that activation of a novel PLD-based signaling pathway may play an important role in the modulation of macrophage function by pore-forming P2z receptors for extracellular ATP.