Berntsen H F, Bogen I L, Wigestrand M B, Fonnum F, Walaas S I, Moldes-Anaya A
Department of Administration, Lab Animal Unit, National Institute of Occupational Health, P.O. Box 8149 Dep, 0033 Oslo, Norway.
Oslo University Hospital, Department of Forensic Sciences, Section of Drug Abuse Research, P.O. Box 4950 Nydalen, N-0424 Oslo, Norway.
Toxicology. 2017 Dec 1;392:64-70. doi: 10.1016/j.tox.2017.10.008. Epub 2017 Oct 13.
Penitrem A is a fungal neurotoxin that recurrently causes intoxication in animals, and occasionally also in humans. We have previously reported that penitrem A induced the production of reactive oxygen species (ROS) in rat cerebellar granule cells, opening for a new mechanism of action for the neurotoxin. The aim of this study was to examine the potential of penitrem A to induce ROS production in isolated human neutrophil granulocytes, and to study possible mechanisms involved. Penitrem A significantly increased the production of ROS in human neutrophils at concentrations as low as 0.25μM (40% increase over basal levels), as measured with the DCF fluorescence assay. The EC determined for the production of ROS by penitrem A was 3.8μM. The maximal increase in ROS production was approximately 330% over basal levels at a concentration of 12.5μM. ROS formation was significantly inhibited by the antioxidant vitamin E (50μM), the intracellular Ca chelator BAPTA-AM (5μM), the mitogen activated protein kinase kinase (MEK) 1/2 and 5 inhibitor U0126 (1 and 10μM), the p38 mitogen activated protein kinase (MAPK) inhibitor SB203580 (1μM), the c-Jun amino-terminal kinase (JNK) inhibitor SP600125 (10μM), and the calcineurin inhibitors FK-506 and cyclosporine A (1.5 and 0.5μM, respectively). These finding suggest that penitrem A is able to induce an increase in ROS production in neutrophils via the activation of several MAPK-signalling pathways. We suggest that this increase may partly explain the pathophysiology generated by penitrem A neuromycotoxicosis in both humans and animals.
青霉震颤素A是一种真菌神经毒素，它经常导致动物中毒，偶尔也会使人类中毒。我们之前曾报道，青霉震颤素A可诱导大鼠小脑颗粒细胞产生活性氧（ROS），为这种神经毒素的新作用机制提供了依据。本研究的目的是检测青霉震颤素A在分离的人中性粒细胞中诱导ROS产生的潜力，并研究其中可能涉及的机制。用DCF荧光分析法测定，青霉震颤素A在低至0.25μM的浓度下就能显著增加人中性粒细胞中ROS的产生（比基础水平增加40%）。青霉震颤素A诱导ROS产生的半数有效浓度（EC）为3.8μM。在浓度为12.5μM时，ROS产生的最大增幅约为基础水平的330%。抗氧化剂维生素E（50μM）、细胞内钙螯合剂BAPTA-AM（5μM）、丝裂原活化蛋白激酶激酶（MEK）1/2和5抑制剂U0126（1和10μM）、p38丝裂原活化蛋白激酶（MAPK）抑制剂SB203580（1μM）、c-Jun氨基末端激酶（JNK）抑制剂SP600125（10μM）以及钙调神经磷酸酶抑制剂FK-506和环孢素A（分别为1.5和0.5μM）均能显著抑制ROS的形成。这些发现表明，青霉震颤素A能够通过激活多种MAPK信号通路诱导中性粒细胞中ROS产生增加。我们认为，这种增加可能部分解释了青霉震颤素A神经霉菌毒素中毒在人类和动物中产生的病理生理学机制。
