Department of Medical Genetic Engineering, Keimyung University School of Medicine, 194 Dongsan-dong, Jung-gu, Daegu 700-712, South Korea.
Toxicol In Vitro. 2010 Jun;24(4):1208-14. doi: 10.1016/j.tiv.2010.02.008. Epub 2010 Feb 10.
High exposure of manganese is believed to be a risk factor for respiratory diseases. Evidence suggests that overexpression of HIF-1alpha transcription factor is linked to pulmonary inflammation and vascular change. In this study, we investigated the effect of manganese-chloride (manganese) on expression and activity of HIF-1alpha in various human airway cells, including Hep2 (laryngeal), H292 (bronchial), and A549 (lung). Profoundly, while manganese treatment led to low or little effect on induction of HIF-1alpha protein in H292 or A549 cells, it strongly induced HIF-1alpha protein expression in Hep2 cells. Mn treatment, however, did not induce HIF-1alpha mRNA expression in Hep2 cells. Luciferase experiments further demonstrated that manganese treatment increased the HRE-driven luciferase activity, suggesting that the induced HIF-1 is functional. Interestingly, manganese treatment also caused activation of p38 MAPK, JNK-1/2, ERK-1/2, and ATF-2, but not of PKB or NF-kappaB in Hep2 cells. Importantly, the manganese-mediated expression and activity of HIF-1alpha protein were largely blocked by treatment with the inhibitor of p38 MAPK (SB203580), JNK-1/2 (SP600125), or ERK-1/2 (PD98059), suggesting roles of these MAPKs in the manganese-induced HIF-1alpha protein expression and activity. Moreover, treatment with SP600125 or SB203580, but not PD98059, had partial inhibitory effects on the stability of HIF-1alpha protein induced by manganese, suggesting that p38 MAPK and JNK-1/2 also contribute to the Mn-mediated HIF-1alpha protein stability. These results suggest that manganese is able to up-regulate HIF-1alpha at the protein level in Hep2 cells and the up-regulation is largely dependent of activities of the family of MAPKs.
高浓度的锰被认为是引发呼吸道疾病的一个风险因素。有证据表明，低氧诱导因子-1α（HIF-1α）转录因子的过度表达与肺部炎症和血管变化有关。在这项研究中，我们研究了氯化锰（锰）对各种人呼吸道细胞中 HIF-1α表达和活性的影响，包括 Hep2（喉）、H292（支气管）和 A549（肺）细胞。令人惊讶的是，尽管锰处理对 H292 或 A549 细胞中 HIF-1α蛋白的诱导作用很小或几乎没有影响，但它能强烈诱导 Hep2 细胞中 HIF-1α蛋白的表达。然而，Mn 处理并没有诱导 Hep2 细胞中 HIF-1α mRNA 的表达。荧光素酶实验进一步表明，锰处理增加了 HRE 驱动的荧光素酶活性，表明诱导的 HIF-1 是有功能的。有趣的是，锰处理还导致 Hep2 细胞中 p38 MAPK、JNK-1/2、ERK-1/2 和 ATF-2 的激活，但不激活 PKB 或 NF-κB。重要的是，用 p38 MAPK（SB203580）、JNK-1/2（SP600125）或 ERK-1/2（PD98059）抑制剂处理后，锰介导的 HIF-1α蛋白的表达和活性在很大程度上被阻断，表明这些 MAPKs 在锰诱导的 HIF-1α蛋白表达和活性中起作用。此外，用 SP600125 或 SB203580 处理，但不用 PD98059 处理，对锰诱导的 HIF-1α蛋白的稳定性有部分抑制作用，表明 p38 MAPK 和 JNK-1/2 也有助于 Mn 介导的 HIF-1α蛋白稳定性。这些结果表明，锰能够在 Hep2 细胞中上调 HIF-1α 蛋白水平，而上调主要依赖于 MAPK 家族的活性。
