Hemin inhibits NO production by IL-1β-stimulated human astrocytes through induction of heme oxygenase-1 and reduction of p38 MAPK activation.
Hemin inhibits NO production by IL-1β-stimulated human astrocytes through induction of heme oxygenase-1 and reduction of p38 MAPK activation.
复制标题
DOI：
10.1186/1742-2094-7-51
复制
发表时间：
2010-09-07
影响因子：
9.3
通讯作者：
Rock RB
中科院分区：
文献类型：
--
作者：
Sheng WS;Hu S;Nettles AR;Lokensgard JR;Vercellotti GM;Rock RB
血红素氧合酶(HO)-1被证明具有减轻氧化损伤和减少细胞凋亡的作用。HO-1可被细胞损伤过程中释放的各种刺激所诱导，如血红素。有害的游离血红素被HO-1降解为一氧化碳、铁和胆绿素，它们具有强大的抗氧化和抗炎特性。在这项研究中，我们验证了HO-1上调会抑制白介素1β激活的人脑星形胶质细胞产生自由基(NO)的假设。在IL-1β暴露前，我们用氯化血红素作为HO-1的诱导剂，锡原卟啉(SnPP)IX作为HO-1的抑制剂，以测定HO-1的产生、诱导型一氧化氮合酶(INOS)、HO-1的表达和丝裂原活化蛋白(MAP)激酶的激活。在IL-1β处理之前，使用携带人HO-1序列的plex表达载体进行星形胶质细胞培养的转染。收集在IL-1β暴露前用p38MAPK或MEK1/2抑制剂处理的星形胶质细胞培养上清液进行NO测定。单独用IL-1β处理星形胶质细胞后，免疫印迹法检测不到HO-1蛋白的表达。然而，IL-1β刺激后，HO-1mRNA表达略有上调。单独使用氯化高铁血红素可显著诱导HO-1m RNA和蛋白的表达，联合应用IL-1β可进一步增强HO-1m RNA的表达。氯化高铁血红素可显著抑制IL-1β诱导的iNOS mRNA表达和NO生成。经SnPP处理后，氯化血红素对IL-1β诱导的NO生成和iNOS表达的抑制作用被逆转，提示HO-1参与了这一过程。IL-1β诱导的p38MAPK激活也被氯化血红素下调，而p38MAPK是产生NO所必需的。这些发现支持这一假说，即星形胶质细胞HO-1的上调与iNOS表达的下调从而NO的产生有关，这一效应涉及p38 MAPK信号通路，这表明这种胶质细胞反应可能对大脑中的氧化应激起到重要的保护作用。
Heme oxygenase (HO)-1 has been shown to attenuate oxidative injury and reduce apoptosis. HO-1 can be induced by various stimuli released during cellular injury, such as heme. Deleterious free heme is degraded by HO-1 to carbon monoxide, iron and biliverdin, which have potent anti-oxidant and anti-inflammatory properties. In this study, we tested the hypothesis that upregulation of HO-1 would inhibit production of the free radical (NO) by interlukin (IL)-1β-activated human astrocytes. To measure NO production, inducible NO synthase (iNOS), HO-1 expression and mitogen-activated protein (MAP) kinase activation we used hemin as an HO-1 inducer and tin protoporphyrin (SnPP) IX as an inhibitor of HO-1 activity in human astrocyte cultures prior to IL-1β exposure. Transfection of astrocyte cultures was performed using a pLEX expression vector carrying the human HO-1 sequence prior to IL-1β treatment. Supernatants of astrocyte cultures pretreated with inhibitors of p38 MAPK or MEK1/2 prior to IL-1β exposure were collected for NO assay. IL-1β treatment of astrocytes alone induced undetectable amounts of HO-1 protein by western blot. However, HO-1 mRNA expression was modestly up-regulated in response to IL-1β stimulation. Pretreatment with hemin alone substantially induced both HO-1 mRNA and protein expression, and HO-1 mRNA expression was further enhanced when hemin was combined with IL-1β treatment. In contrast, IL-1β-induced iNOS mRNA expression and NO production were markedly inhibited by hemin treatment. When pretreated with SnPP, the inhibitory effect of hemin on IL-1β-induced NO production and iNOS expression was reversed, suggesting the involvement of HO-1. IL-1β-induced p38 MAPK activation, which is known to be required for NO production, was also down-regulated by hemin. These findings support the hypothesis that up-regulation of HO-1 in astrocytes is associated with down-regulation of iNOS expression and thereby NO production, an effect that involves the p38 MAPK signaling pathway, which suggests that this glial cell response could play an important protective role against oxidative stress in the brain.
登录
查看更多内容
影响因子：
6.7
作者：
通讯作者：
--
影响因子：
4.4
作者：
Devadas, Krishnakumar;Dhawan, Subhash
通讯作者：
Dhawan, Subhash
影响因子：
2.6
作者：
Huang, Y.;Wu, L.;Wang, R.
通讯作者：
Wang, R.
影响因子：
3.5
作者：
EWING, JF;MAINES, MD
通讯作者：
MAINES, MD
影响因子：
7.4
作者：
Laird, Melissa D.;Wakade, Chandramohan;Dhandapani, Krishnan M.
通讯作者：
Dhandapani, Krishnan M.