Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
PLoS One. 2012;7(6):e38899. doi: 10.1371/journal.pone.0038899. Epub 2012 Jun 22.
Endogenous damage associated molecular pattern molecules (DAMPs) released from necrotic, damaged or stressed cells are associated with an inflammatory response. Whether the microRNA (miR) expression signature of this response is different from that of a pathogen associated molecular pattern (PAMP)-stimulated inflammatory response is unknown. We report here that miR-34c and miR-214 are significantly expressed in fresh human peripheral blood mononuclear cells (PBMCs) exposed to DAMP-containing freeze-thaw lysates, or to conditioned media from serum-starved and glucose-deprived cells (p<6×10(-4) and p<3.7×10(-3)), respectively. Interestingly, only miR-34c expression was differentially expressed in PBMCs exposed to freeze-thaw lysates or conditioned media from wildtype High Mobility Group B1 (HMGB1(+/+)) mouse embryonic fibroblast (MEF) cells, when compared to cultures exposed to lysates or conditioned media from HMGB1(-/-) MEFs. miR-155 expression in these cultures was negligible, but was significantly expressed in PBMCs stimulated with Lipopolysaccahride (LPS) or most other Toll-like receptor (TLR) ligands, making it the prototypic "PAMPmiR". Exposure to a damaged human colorectal carcinoma cell line lysate (HCT116) similarly resulted in increased miR-34c and miR-214 levels. When PBMCs were pre-transfected with anti-miR-34c and then exposed to lysate, expression levels of IKKγ mRNA, a putative target of miR-34c, increased, while protein levels of IKKγ in cultures transfected with a pre-miR-34c were abrogated. Levels of miR-34c expression (as well as pro-inflammatory cytokines, IL-1β and TNFα) decreased when PBMC cultures were briefly pre-incubated with the K(+) channel (inflammasome) inhibitor, glybenclamide, suggesting that inflammasome activation is upstream of miR-34c expression in response to DAMPs. Our findings demonstrate that a specific microRNA expression signature is associated with the inflammatory response to damaged/injured cells and carries implications for many acute and chronic inflammatory disorders.
内源性损伤相关分子模式分子（DAMPs）从坏死、损伤或应激细胞中释放出来，与炎症反应有关。这种反应的 microRNA（miR）表达特征是否与病原体相关分子模式（PAMP）刺激的炎症反应不同尚不清楚。我们在这里报告，miR-34c 和 miR-214 在新鲜的人外周血单核细胞（PBMC）暴露于含有 DAMP 的冻融裂解物或血清饥饿和葡萄糖剥夺细胞的条件培养基中显著表达（p<6×10(-4) 和 p<3.7×10(-3)），分别。有趣的是，只有 miR-34c 的表达在 PBMC 暴露于冻融裂解物或源自野生型高迁移率族蛋白 B1（HMGB1(+/+)）小鼠胚胎成纤维细胞（MEF）的条件培养基时发生差异表达，与暴露于 HMGB1(-/-) MEF 的培养基相比。这些培养物中的 miR-155 表达可忽略不计，但在 PBMC 受到脂多糖（LPS）或大多数其他 Toll 样受体（TLR）配体刺激时显著表达，使其成为典型的“PAMPmiR”。暴露于受损的人结直肠癌细胞系裂解物（HCT116）同样导致 miR-34c 和 miR-214 水平增加。当 PBMC 用抗 miR-34c 预先转染然后暴露于裂解物时，miR-34c 的假定靶标 IKKγ mRNA 的表达水平增加，而在用前 miR-34c 转染的培养物中 IKKγ 的蛋白水平被阻断。当 PBMC 培养物与 K(+) 通道（炎症小体）抑制剂格列本脲短暂预孵育时，miR-34c 的表达水平（以及促炎细胞因子 IL-1β 和 TNFα）降低，表明炎症小体激活是 DAMPs 反应中 miR-34c 表达的上游事件。我们的发现表明，特定的 microRNA 表达特征与受损/损伤细胞的炎症反应有关，并对许多急性和慢性炎症性疾病具有重要意义。
