Univ Paris-Sud, UMR-S 757, Orsay, F-91405, France.
J Hepatol. 2010 Jan;52(1):54-62. doi: 10.1016/j.jhep.2009.10.005. Epub 2009 Oct 24.
BACKGROUND & AIMS: Paracrine interactions are critical to liver physiology, particularly during regeneration, although physiological involvement of extracellular ATP, a crucial intercellular messenger, remains unclear. The physiological release of ATP into extracellular milieu and its impact on regeneration after partial hepatectomy were investigated in this study.
Hepatic ATP release after hepatectomy was examined in the rat and in human living donors for liver transplantation. Quinacrine was used for in vivo staining of ATP-enriched compartments in rat liver sections and isolated hepatocytes. Rats were treated with an antagonist for purinergic receptors (Phosphate-6-azo(benzene-2,4-disulfonic acid), PPADS), and liver regeneration after hepatectomy was analyzed.
A robust and transient ATP release due to acute portal hyperpressure was observed immediately after hepatectomy in rats and humans. Clodronate liposomal pre-treatment partly inhibited ATP release in rats. Quinacrine-stained vesicles, co-labeled with a lysosomal marker in liver sections and isolated hepatocytes, were predominantly detected in periportal areas. These vesicles significantly disappeared after hepatectomy, in parallel with a decrease in liver ATP content. PPADS treatment inhibited hepatocyte cell cycle progression after hepatectomy, as revealed by a reduction in bromodeoxyuridine incorporation, phosphorylated histone 3 immunostaining, cyclin D1 and A expression and immediate early gene induction.
Extracellular ATP is released immediately after hepatectomy from hepatocytes and Kupffer cells under mechanical stress and promotes liver regeneration in the rat. We suggest that in hepatocytes, ATP is released from a lysosomal compartment. Finally, observations made in living donors suggest that purinergic signalling could be critical for human liver regeneration.
旁分泌相互作用对肝脏生理功能至关重要，尤其是在再生过程中，尽管细胞外 ATP（一种关键的细胞间信使）的生理作用仍不清楚。本研究旨在探讨 ATP 在外周环境中的生理释放及其对肝部分切除后再生的影响。
在大鼠和接受肝移植的人类活体供者中，检测肝切除术后肝组织 ATP 的释放。在大鼠肝组织切片和分离的肝细胞中，使用吖啶橙来对富含 ATP 的隔室进行活体染色。用嘌呤能受体拮抗剂（Phosphate-6-azo(benzene-2,4-disulfonic acid)，PPADS）处理大鼠，分析肝切除术后的肝再生情况。
在大鼠和人类中，肝切除术后立即观察到急性门静脉高压导致的强烈而短暂的 ATP 释放。氯膦酸盐脂质体预处理部分抑制了大鼠的 ATP 释放。吖啶橙染色的囊泡在肝组织切片和分离的肝细胞中与溶酶体标记物共标记，主要存在于门脉周围区域。这些囊泡在肝切除术后明显消失，与肝组织 ATP 含量降低平行。PPADS 处理抑制了肝切除术后的肝细胞细胞周期进程，表现在溴脱氧尿苷掺入减少、磷酸化组蛋白 3 免疫染色、周期蛋白 D1 和 A 的表达以及即刻早期基因诱导减少。
机械应激下，肝切除术后肝细胞和枯否细胞立即释放细胞外 ATP，并促进大鼠的肝再生。我们推测，在肝细 胞中，ATP 从溶酶体隔室释放。最后，在活体供者中的观察结果表明，嘌呤能信号可能对人类肝再生至关重要。
