Alternatively-spliced extra domain A of fibronectin promotes acute inflammation and brain injury after cerebral ischemia in mice.
Alternatively-spliced extra domain A of fibronectin promotes acute inflammation and brain injury after cerebral ischemia in mice.
复制标题
DOI：
10.1161/strokeaha.111.635516
复制
发表时间：
2012-05
期刊：
影响因子：
8.3
通讯作者：
Chauhan AK
中科院分区：
文献类型：
--
作者：
Khan MM;Gandhi C;Chauhan N;Stevens JW;Motto DG;Lentz SR;Chauhan AK
含有选择性剪接额外结构域A的纤维连接蛋白亚型(EDA+-FN)通常不存在于循环中，但在包括缺血性中风在内的几种与炎症相关的人类病理条件下，血浆EDA+-FN水平会显著升高。目前尚不清楚EDA+-FN是否参与了卒中的发病，还是仅仅是一个关联标记物。几项体外研究表明，EDA+-FN可以激活Toll样受体4(TLR4)，这是一种触发促炎反应的先天免疫受体。我们在小鼠中采用遗传学方法研究EDA+-FN在局灶性脑缺血/再灌注损伤模型中介导炎性脑损伤的能力。我们使用了转基因的EDA+/+小鼠，它们结构性地表达EDA+-FN。评估脑缺血1小时/23小时再灌注损伤后的损伤程度、神经转归和炎症机制，并与野生型(WT)小鼠进行比较。我们发现EDA+/+小鼠出现明显的更大的梗塞和严重的神经功能缺失，这与免疫组织化学定量的中性粒细胞和巨噬细胞的显著增加有关。此外，我们还发现，与WT小鼠相比，EDA+/+小鼠的NF-κB、COX-2和炎性细胞因子肿瘤坏死因子α、IL-1β和IL-6表达上调。有趣的是，在EDA+/+小鼠中，通过使用特定的TLR4抑制剂治疗，增加的脑损伤和神经功能障碍在很大程度上被消除。这些发现首次证明EDA+-FN促进了缺血性卒中后的炎症性脑损伤，并提示在慢性炎症条件下观察到的血浆EDA+-FN水平的升高可能会加重急性卒中后的损伤和预后。
The fibronectin isoform containing the alternatively-spliced extra domain A (EDA+-FN) is normally absent from the circulation, but plasma levels of EDA+-FN can become markedly elevated in several human pathological conditions associated with inflammation including ischemic stroke. It remains unknown whether EDA+-FN contributes to stroke pathogenesis or is simply an associative marker. Several in vitro studies suggest that EDA+-FN can activate toll-like receptor 4 (TLR4), an innate immune receptor that triggers pro-inflammatory responses. We undertook a genetic approach in mice to investigate the ability of EDA+-FN to mediate inflammatory brain damage in a focal cerebral ischemia/reperfusion injury model. We used genetically modified EDA+/+ mice, which constitutively express EDA+-FN. Extent of injury, neurological outcome and inflammatory mechanisms were assessed following one hour cerebral ischemia/23 hour reperfusion injury and compared to wild-type (WT) mice. We found that EDA+/+ mice developed significantly larger infarcts and severe neurological deficits that was associated with significant increased neutrophil and macrophage infiltration as quantitated by immunohistochemistry. Additionally, we found upregulation of NF-κB, COX-2, and inflammatory cytokines TNFα, IL-1β and IL-6 in the EDA+/+ mice compared to WT mice. Interestingly, increased brain injury and neurological deficits were largely abrogated in EDA+/+ mice by treatment with a specific TLR4 inhibitor. These findings provide the first evidence that EDA+-FN promotes inflammatory brain injury following ischemic stroke and suggest that the elevated levels of plasma EDA+-FN observed in chronic inflammatory conditions could worsen injury and outcome in patients following acute stroke.