Makni-Maalej Karama, Marzaioli Viviana, Boussetta Tarek, Belambri Sahra Amel, Gougerot-Pocidalo Marie-Anne, Hurtado-Nedelec Margarita, Dang Pham My-Chan, El-Benna Jamel
*Institut National de la Santé et de la Recherche Médicale, U1149, Centre National de la Recherche Scientifique-ERL8252, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, Faculté de Médecine, Paris, France ; Assistance publique-Hôpitaux de Paris, Hôpitaux Universitaires Paris Nord Val de Seine Bichat-Claude Bernard, Unité Fonctionnelle Dysfonctionnements Immunitaires, Paris, France; and Laboratoire de Biochimie Appliquée, Université Ferhat Abbas, Sétif, Algéria.
*Institut National de la Santé et de la Recherche Médicale, U1149, Centre National de la Recherche Scientifique-ERL8252, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, Faculté de Médecine, Paris, France ; Assistance publique-Hôpitaux de Paris, Hôpitaux Universitaires Paris Nord Val de Seine Bichat-Claude Bernard, Unité Fonctionnelle Dysfonctionnements Immunitaires, Paris, France; and Laboratoire de Biochimie Appliquée, Université Ferhat Abbas, Sétif, Algéria
J Leukoc Biol. 2015 Jun;97(6):1081-7. doi: 10.1189/jlb.2A1214-623R. Epub 2015 Apr 15.
Neutrophils play a key role in host defense against invading pathogens by releasing toxic agents, such as ROS and antimicrobial peptides. Human neutrophils express several TLRs that recognize a variety of microbial motifs. The interaction between TLR and their agonists is believed to help neutrophils to recognize and to kill pathogens efficiently by increasing their activation, a process called priming. However, excessive activation can induce tissue injury and thereby, contribute to inflammatory disorders. Agonists that activate TLR7 and TLR8 induce priming of neutrophil ROS production; however, which receptor is involved in this process has not been elucidated. In this study, we show that the selective TLR8 agonist, CL075 (3M002), induced a dramatic increase of fMLF-stimulated NOX2 activation, whereas the selective TLR7 agonist, loxoribine, failed to induce any priming effect. Interestingly, CL075, but not loxoribine, induced the phosphorylation of the NOX2 cytosolic component p47phox on several serines and the phosphorylation of p38MAPK and ERK1/2. The inhibitor of p38MAPK completely blocked CL075-induced phosphorylation of p47phox Ser345. Moreover, CL075, but not loxoribine, induced the activation of the proline isomerase Pin1, and juglone, a Pin1 inhibitor, prevented CL075-mediated priming of fMLF-induced superoxide production. These results indicate that TLR8, but not TLR7, is involved in priming of human neutrophil ROS production by inducing the phosphorylation of p47phox and p38MAPK and that Pin1 is also involved in this process.
中性粒细胞通过释放活性氧（ROS）和抗菌肽等毒性因子，在宿主抵御入侵病原体的防御中发挥关键作用。人类中性粒细胞表达多种可识别各种微生物基序的Toll样受体（TLR）。TLR与其激动剂之间的相互作用被认为有助于中性粒细胞通过增强其活化来有效识别和杀死病原体，这一过程称为预激活。然而，过度激活会导致组织损伤，进而引发炎症性疾病。激活TLR7和TLR8的激动剂可诱导中性粒细胞ROS产生的预激活；然而，该过程涉及哪种受体尚未阐明。在本研究中，我们发现选择性TLR8激动剂CL075（3M002）可显著增加甲酰甲硫氨酸-亮氨酸-苯丙氨酸（fMLF）刺激的NOX2活化，而选择性TLR7激动剂洛索立宾未能诱导任何预激活效应。有趣的是，CL075而非洛索立宾可诱导NOX2胞质成分p47phox在多个丝氨酸位点的磷酸化以及p38丝裂原活化蛋白激酶（p38MAPK）和细胞外信号调节激酶1/2（ERK1/2）的磷酸化。p38MAPK抑制剂可完全阻断CL075诱导的p47phox丝氨酸345位点的磷酸化。此外，CL075而非洛索立宾可诱导脯氨酸异构酶Pin1的活化，而Pin1抑制剂胡桃醌可阻止CL075介导的fMLF诱导的超氧化物产生的预激活。这些结果表明，TLR8而非TLR7通过诱导p47phox和p38MAPK的磷酸化参与人类中性粒细胞ROS产生的预激活，并且Pin1也参与该过程。
