Ramnath Raina Devi, Sun Jia, Adhikari Sharmila, Zhi Liang, Bhatia Madhav
Dept. of Pharmacology, National Univ. of Singapore, Yong Loo Lin School of Medicine, Centre for life Sciences, 28 Medical Drive, Singapore 117456.
Am J Physiol Cell Physiol. 2008 Mar;294(3):C683-92. doi: 10.1152/ajpcell.00360.2007. Epub 2007 Dec 26.
Interaction of the neuropeptide substance P (SP) with its high-affinity neurokinin-1 receptor (NK1R) plays an important role in the pathophysiology of acute pancreatitis. SP is known to stimulate the production of chemokines monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1 alpha, and MIP-2 in pancreatic acinar cells via the activation of NF-kappaB. However, the signaling mechanisms by which the SP-NK1R interaction induces NF-kappaB activation and chemokine production remain unclear. To that end, in the present study, we investigated the participation of PKC in SP-induced chemokine production in pancreatic acinar cells. In this study, we showed that SP stimulated an early phosphorylation of PKC isoform PKC-delta followed by increased activation of MAPKKK MEKK1 and MAPK ERK and JNK as well as transcription factor NF-kappaB and activator protein-1 driven chemokine production. Depletion of PKC-delta with its inhibitor rottlerin or the specific PKC-delta translocation inhibitor peptide dose dependently decreased SP-induced PKC-delta, MEKK1, ERK, JNK, NF-kappaB, and AP-1 activation. Moreover, rottlerin as well as PKC-delta translocation inhibitor inhibited SP-induced chemokine production in a concentration-dependent manner. We also demonstrated that PKC-delta activation was attenuated by CP96345, a selective NK1R antagonist, thus showing that PKC-delta activation was indeed mediated by SP in pancreatic acinar cells. These results show that PKC-delta is an important proinflammatory signal transducer for SP-NK1R-induced chemokine production in pancreatic acinar cells.
神经肽P物质（SP）与其高亲和力神经激肽-1受体（NK1R）的相互作用在急性胰腺炎的病理生理学中起重要作用。已知SP通过激活核因子κB（NF-κB）刺激胰腺腺泡细胞中趋化因子单核细胞趋化蛋白-1（MCP-1）、巨噬细胞炎性蛋白（MIP）-1α和MIP-2的产生。然而，SP-NK1R相互作用诱导NF-κB激活和趋化因子产生的信号传导机制仍不清楚。为此，在本研究中，我们调查了蛋白激酶C（PKC）在SP诱导的胰腺腺泡细胞趋化因子产生中的参与情况。在本研究中，我们表明SP刺激PKC亚型PKC-δ的早期磷酸化，随后丝裂原活化蛋白激酶激酶激酶（MAPKKK）MEKK1、丝裂原活化蛋白激酶（MAPK）细胞外信号调节激酶（ERK）和应激活化蛋白激酶（JNK）以及转录因子NF-κB和活化蛋白-1驱动的趋化因子产生的激活增加。用其抑制剂rottlerin或特异性PKC-δ易位抑制剂肽消耗PKC-δ剂量依赖性地降低SP诱导的PKC-δ、MEKK1、ERK、JNK、NF-κB和AP-1激活。此外，rottlerin以及PKC-δ易位抑制剂以浓度依赖性方式抑制SP诱导的趋化因子产生。我们还证明，选择性NK1R拮抗剂CP96345减弱了PKC-δ的激活，从而表明PKC-δ的激活确实由胰腺腺泡细胞中的SP介导。这些结果表明，PKC-δ是SP-NK1R诱导的胰腺腺泡细胞趋化因子产生的重要促炎信号转导分子。
