Nuche-Berenguer Bernardo, Ramos-Álvarez Irene, Jensen R T
Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA.
Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA.
Biochim Biophys Acta. 2016 Jun;1862(6):1122-36. doi: 10.1016/j.bbadis.2016.02.008. Epub 2016 Feb 18.
In a recent study we explored Group-1-p21-activated kinases (GP.1-PAKs) in rat pancreatic acini. Only PAK2 was present; it was activated by gastrointestinal-hormones/neurotransmitters and growth factors in a PKC-, Src- and small-GTPase-mediated manner. PAK2 was required for enzyme-secretion and ERK/1-2-activation. In the present study we examined PAK2's role in CCK and TPA-activation of important distal signaling cascades mediating their physiological/pathophysiological effects and analyzed its role in pathophysiological processes important in early pancreatitis. In rat pancreatic acini, PAK2-inhibition by the specific, GP.1.PAK-inhibitor, IPA-3-suppressed cholecystokinin (CCK)/TPA-stimulated activation of focal-adhesion kinases and mitogen-activated protein-kinases. PAK2-inhibition reversed the dual stimulatory/inhibitory effect of CCK/TPA on the PI3K/Akt/GSK-3β pathway. However, its inhibition did not affect PKC activation. PAK2-inhibition protected acini from CCK-induced ROS-generation; caspase/trypsin-activation, important in early pancreatitis; as well as from cell-necrosis. Furthermore, PAK2-inhibition reduced proteolytic-activation of PAK-2p34, which is involved in programmed-cell-death. To ensure that the study did not only rely in the specificity of IPA-3 as a PAK inhibitor, we used two other approaches for PAK inhibition, FRAX597 a ATP-competitive-GP.1-PAKs-inhibitor and infection with a PAK2-dominant negative(DN)-Advirus. Those two approaches confirmed the results obtained with IPA-3. This study demonstrates that PAK2 is important in mediating CCK's effect on the activation of signaling-pathways known to mediate its physiological/pathophysiological responses including several cellular processes linked to the onset of pancreatitis. Our results suggest that PAK2 could be a new, important therapeutic target to consider for the treatment of diseases involving deregulation of pancreatic acinar cells.
在最近的一项研究中，我们对大鼠胰腺腺泡中的1型p21激活激酶（GP.1-PAKs）进行了探究。仅存在PAK2；它可被胃肠激素/神经递质和生长因子以PKC、Src和小GTP酶介导的方式激活。酶分泌和ERK/1-2激活需要PAK2。在本研究中，我们研究了PAK2在介导胆囊收缩素（CCK）和佛波酯（TPA）的重要远端信号级联激活中的作用，这些信号级联介导了它们的生理/病理生理效应，并分析了其在早期胰腺炎重要病理生理过程中的作用。在大鼠胰腺腺泡中，特异性的GP.1.PAK抑制剂IPA-3抑制PAK2可抑制胆囊收缩素（CCK）/TPA刺激的粘着斑激酶和丝裂原活化蛋白激酶的激活。抑制PAK2可逆转CCK/TPA对PI3K/Akt/GSK-3β信号通路的双重刺激/抑制作用。然而，其抑制作用并不影响PKC的激活。抑制PAK2可保护腺泡免受CCK诱导的活性氧生成；半胱天冬酶/胰蛋白酶激活（这在早期胰腺炎中很重要）；以及细胞坏死。此外，抑制PAK2可减少参与程序性细胞死亡的PAK-2p34的蛋白水解激活。为确保该研究不仅依赖于IPA-3作为PAK抑制剂的特异性，我们使用了另外两种抑制PAK的方法，即ATP竞争性GP.1-PAKs抑制剂FRAX597和感染PAK2显性阴性（DN）腺病毒。这两种方法证实了用IPA-3获得的结果。本研究表明，PAK2在介导CCK对已知介导其生理/病理生理反应的信号通路激活的作用中很重要，这些反应包括与胰腺炎发病相关的几个细胞过程。我们的结果表明，PAK2可能是治疗涉及胰腺腺泡细胞失调疾病的一个新的重要治疗靶点。
