Long Non-Coding RNA, TLR Tolerance and Sepsis

脓毒症仍然是美国的主要健康威胁之一，影响着大约75万美国人 死亡率高达50%。许多败血症患者在最初的“细胞因子风暴”中幸存下来 但会产生严重的免疫抑制，免疫受损并屈从于 继发性感染。这种免疫功能低下的脓毒症患者的单核细胞 程序化的Toll样受体(TLR)4信号，显示抑制的促炎作用 细胞因子，但抗炎和抗微生物表达不变或增加 中介物，让人想起内毒素耐受性。长的非编码RNA(LncRNAs)最近 作为TLR信号通路的新调节者，但lncRNAs的变化如何重新塑造 在TLR耐受和脓毒症期间，髓系细胞的反应程序尚不清楚。我们的 初步和已发表的数据已在人类THP1单核细胞和小鼠中发现了lncRNAs 巨噬细胞在TLR4攻击和内毒素耐受时表达的显著变化。 我们发现在THP-1细胞中PCGEM1 lncRNA的敲除和天然反义的缺陷 小鼠巨噬细胞中的转录-IL-1α、Linc-COX2或EPS基因显著影响内毒素信号转导。 我们还发现，Eps-/-MS在诱导内毒素耐受方面存在妥协。这些数据 支持我们的假设，即髓系细胞中lncRNAs表达和功能的改变促进 TLR耐受性和脓毒症相关的免疫抑制 炎症介质的转录水平和转录后调控。为了测试这一点 假设，我们设计了以下具体目标：1.确定TLR4耐受的影响 和脓毒症对髓系细胞中lncRNAs表达的影响；以及2.确定LncRNAs在髓系细胞中的功能意义 LncRNAs在TLR4信号和耐受中的作用。在完成这个项目后，我们将确定 LncRNAs在TLR耐受形成过程中对髓系细胞TLR信号的“重新编程” 还有败血症。这个项目有望提高我们对以下机制的理解 LncRNAs调节髓系细胞的抗微生物反应，并确定其分子靶点 用于未来对人类脓毒症患者的转译研究。这些进展将是关键 美国改善脓毒症治疗的重要性。

Sepsis remains one of the major health threats in the U. S., affecting ~750,000 Americans per year, with mortality rate up to 50%. Many septic patients survive the initial “cytokine storm” but develop profound immunosuppression, become immunocompromised and succumb to secondary infections. Monocytes from such immunocompromised septic patients have “re- programmed” Toll-like receptor (TLR) 4 signaling, showing suppressed pro-inflammatory cytokines but unchanged or increased expression of anti-inflammatory and anti-microbial mediators, reminiscent of endotoxin tolerance. Long non-coding RNAs (lncRNAs) have recently emerged as new regulators of TLR signaling pathways, but how changes in lncRNAs “shape” re- programming of responses of myeloid cells during TLR tolerance and sepsis is unknown. Our preliminary and published data has identified lncRNAs in human THP1 monocytes and mouse macrophages with significant changes in expression upon TLR4 challenge and endotoxin tolerization. We showed that knock-down of PCGEM1 lncRNA in THP-1 cells and deficiencies of natural antisense transcript-IL-1α, linc-Cox2 or Eps lncRNAs in mouse macrophages significantly affect LPS signaling. We also found that Eps-/- Ms are compromised in the induction of endotoxin tolerance. These data supports our hypothesis that altered expression and functions of lncRNAs in myeloid cells promote TLR tolerance and sepsis-associated immunosuppression by reprogramming TLR responses at the level transcriptional and post-transcriptional regulation of inflammatory mediators. To test this hypothesis, we have designed the following Specific Aims: 1. Identify the impact of TLR4 tolerance and sepsis on expression of lncRNAs in myeloid cells; and 2. Determine the functional significance for lncRNAs in TLR4 signaling and tolerance. Having completed this project, we will determine the role for lncRNAs in “reprogramming” of TLR signaling in myeloid cells during development of TLR tolerance and sepsis. This project is expected to improve our understanding of the mechanisms by which lncRNAs modulate antimicrobial responses of myeloid cells, and define molecular targets of lncRNAs for future translational research in human patients with sepsis. These advances would be of key importance for improving treatment of sepsis in the U.S.