Department of Clinical Science and Education, Karolinska Institutet, Research Centre, Stockholm South Hospital, Stockholm, Sweden.
Mol Cell Endocrinol. 2011 Feb 10;333(1):8-19. doi: 10.1016/j.mce.2010.11.004. Epub 2010 Nov 19.
The mechanism by which extracellular ADP ribose (ADPr) increases intracellular free Ca(2+) concentration (Ca(2+)) remains unknown. We measured Ca(2+) changes in fura-2 loaded rat insulinoma INS-1E cells, and in primary β-cells from rat and human. A phosphonate analogue of ADPr (PADPr) and 8-Bromo-ADPr (8Br-ADPr) were synthesized. ADPr increased Ca(2+) in the form of a peak followed by a plateau dependent on extracellular Ca(2+). NAD(+), cADPr, PADPr, 8Br-ADPr or breakdown products of ADPr did not increase Ca(2+). The ADPr-induced Ca(2+) increase was not affected by inhibitors of TRPM2, but was abolished by thapsigargin and inhibited when phospholipase C and IP(3) receptors were inhibited. MRS 2179 and MRS 2279, specific inhibitors of the purinergic receptor P2Y1, completely blocked the ADPr-induced Ca(2+) increase. ADPr increased Ca(2+) in transfected human astrocytoma cells (1321N1) that express human P2Y1 receptors, but not in untransfected astrocytoma cells. We conclude that ADPr is a specific agonist of P2Y1 receptors.
细胞外 ADP 核糖（ADPr）增加细胞内游离 Ca(2+)浓度 (Ca(2+))的机制尚不清楚。我们测量了负载 fura-2 的大鼠胰岛素瘤 INS-1E 细胞以及大鼠和人原代β细胞中的 Ca(2+)变化。合成了 ADPr 的膦酸类似物 (PADPr) 和 8-溴-ADPr (8Br-ADPr)。ADPr 以依赖细胞外 Ca(2+)的峰后平台的形式增加 Ca(2+)。NAD(+)、cADPr、PADPr、8Br-ADPr 或 ADPr 的分解产物均未增加 Ca(2+)。ADPr 诱导的 Ca(2+)增加不受 TRPM2 抑制剂的影响，但被 thapsigargin 消除，并在抑制磷脂酶 C 和 IP(3) 受体时受到抑制。特异性嘌呤能受体 P2Y1 抑制剂 MRS 2179 和 MRS 2279 完全阻断了 ADPr 诱导的 Ca(2+)增加。ADPr 增加了表达人 P2Y1 受体的转染人星形细胞瘤细胞 (1321N1)中的 Ca(2+)，但未增加未转染的星形细胞瘤细胞中的 Ca(2+)。我们得出结论，ADPr 是 P2Y1 受体的特异性激动剂。
