Adenosine Triphosphate Release and Purinergic (P2) Receptor-Mediated Secretion in Small and Large Mouse Cholangiocytes
Adenosine Triphosphate Release and Purinergic (P2) Receptor-Mediated Secretion in Small and Large Mouse Cholangiocytes
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DOI：
10.1002/hep.23883
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发表时间：
2010-11-01
期刊：
影响因子：
13.5
通讯作者：
Feranchak, Andrew P.
中科院分区：
文献类型：
--
作者：
Woo, Kangmee;Sathe, Meghana;Feranchak, Andrew P.
三磷酸腺苷（ATP）从胆管细胞释放到胆汁中，是一种有效的促分泌剂，通过结合尖膜上的嘌呤能（P2）受体，增加细胞内Ca2+并刺激液体和电解质分泌。尽管小胆管细胞和大胆管细胞（分别位于小胆管和大胆管内壁）之间存在形态差异，但P2信号传导在肝内胆管上皮中的作用此前尚未得到评估。因此，这些研究的目的是表征小（MSC）和大（MLC）小鼠胆管细胞中的ATP释放和p2信号通路。结果表明，MSCs和MLCs均表达P2受体，包括P2X4和P2Y2。暴露于细胞外核苷酸（ATP，尿苷三磷酸，或2',3'- o-[4-苯甲酰-苯甲酰]-ATP）导致细胞内Ca2+浓度和经上皮分泌迅速增加（4,），这两种细胞类型被Cl通道阻滞剂5-硝基-2-（-3-苯丙胺）-苯甲酸（NPPB）或尼氟酸抑制。在机械刺激（流/剪切或低渗暴露引起的细胞肿胀）的反应中，MSCs和MLCs的胞吐率都显著增加，这与ATP释放的增加是平行的。与MLCs相比，MSCs的机械敏感性ATP释放量增加了两倍。在两种细胞类型中，莫能菌素破坏囊泡运输可显著抑制ATP释放。结论：这些发现提示沿肝内胆管存在P2信号轴，其“上游”MSCs释放ATP，可作为“下游”MLCs刺激Ca2+依赖性分泌的旁分泌信号分子。此外，在不表达囊性纤维化跨膜传导调节因子的MSCs中，响应细胞外核苷酸的Ca2+激活的Cl-外排代表了在这些源自小肝内管的胆管细胞中明确确定的第一种分泌途径。(肝脏病学52:1819 2010;1828)
Adenosine triphosphate (ATP) is released from cholangiocytes into bile and is a potent secretogogue by increasing intracellular Ca2+ and stimulating fluid and electrolyte secretion via binding purinergic (P2) receptors on the apical membrane. Although morphological differences exist between small and large cholangiocytes (lining small and large bile ducts, respectively), the role of P2 signaling has not been previously evaluated along the intrahepatic biliary epithelium. The aim of these studies therefore was to characterize ATP release and P2-signaling pathways in small (MSC) and large (MLC) mouse cholangiocytes. The findings reveal that both MSCs and MLCs express P2 receptors, including P2X4 and P2Y2. Exposure to extracellular nucleotides (ATP, uridine triphosphate, or 2',3'-O-[4-benzoyl-benzoy1]-ATP) caused a rapid increase in intracellular Ca2+ concentration and in transepithelial secretion (4,) in both cell types, which was inhibited by the Cl channel blockers 5-nitro-2-(-3-phenylpropylamino)-benzoic acid (NPPB) or niflumic acid. In response to mechanical stimulation (flow/shear or cell swelling secondary to hypotonic exposure), both MSCs and MLCs exhibited a significant increase in the rate of exocytosis, which was paralleled by an increase in ATP release. Mechanosensitive ATP release was two-fold greater in MSCs compared to MLCs. ATP release was significantly inhibited by disruption of vesicular trafficking by monensin in both cell types. Conclusion: These findings suggest the existence of a P2 signaling axis along intrahepatic biliary ducts with the "upstream" MSCs releasing ATP, which can serve as a paracrine signaling molecule to "downstream" MLCs stimulating Ca2+-dependent secretion. Additionally, in MSCs, which do not express the cystic fibrosis transmembrane conductance regulator, Ca2+-activated Cl- efflux in response to extracellular nucleotides represents the first secretory pathway clearly identified in these cholangiocytes derived from the small intrahepatic ducts. (HEPATOLOGY 2010;52:1819-1828)