Mechanisms of Inflammation in Sickle Cell Disease

项目摘要/摘要 大量研究表明，镰状细胞病(SCD)引起血管病变和 血管充血增加是复杂的和多因素的。在这份修订后的续订申请中，我们假设 SCD诱导血管病变是SCD增加血管病变机制的第一步之一。 遮挡。我们的研究表明，SCD会引发由MPO引发的破坏性循环，并通过 高迁移率族蛋白-1(HMGB1)，以及另一种改变肺生理的炎症成分， 损害血管功能，增加血管充血。 此前，我们报道了L-乙酰赖氨酰半胱氨酸酰胺(KYC)抑制MPO，改善血管功能和 减轻SCD小鼠过度血管淤血所致的肝损伤。新的研究表明，KYC不仅 减少镰状红细胞(SRBC)充血，但也增加SCD小鼠肺中圆形SRBC的数量。 机理研究表明，KYC不仅是MPO有毒氧化剂产生的抑制剂，而且是一种独特的 利用MPO过氧化物酶活性转化为新型抗炎剂的三肽底物 使HMGB1失活并激活负责抗氧化防御酶的细胞通路 在肺中的表达。由于KYC在我们假设的破坏性周期中抑制了多种炎症成分， 甚至激活了一种介导抗氧化剂基因表达的成分，这是一项使用机械论的新研究 需要使用抑制剂来确定哪些成分会增加SCD的血管病变和血管充血。 虽然系统药剂可能对治疗多因素疾病有用，但它们不能用于 直接确定因果机制。在这个修订的应用中，我们假设SCD导致破坏性的 周期，至少由三个主要组成部分调节。我们的工作假设是SCD会导致破坏性的循环 它由MPO、HMGB1和一种新的、失调的基因组成，共同诱导血管病变和 增加血管充血。通过治疗镰刀鼠、镰刀MPO基因敲除(KO)小鼠、嵌合镰刀他莫昔芬- 用高选择性机制抑制剂诱导HMGB1 KO小鼠和另一种嵌合镰刀KO小鼠 将能够单独和/或确定MPO、HMGB1和第三基因产物是否以及在多大程度上 联合使用会导致血管病变并增加血管充血。为了评估血管病变，我们将量化 肺动脉松弛、肺通透性、SRBC血管充血和易感性的差异 不同品系小鼠对缺氧-复氧损伤(HRI)所致SRBC血管淤血的影响 纯合子镰刀HB(SS)wt SS MPO Ko小鼠和嵌合SS新基因Ko小鼠。我们的长期目标是 确认每种成分的特性，并开发旨在改善血管功能的新疗法 减少SRBC血管充血。

Project Summary/Abstract Numerous studies show the mechanisms by which sickle cell disease (SCD) induces vasculopathy and increases vasocongestion are complex and multifactorial. In this revised, renewal application, we hypothesize that SCD induces vasculopathy as one of the first steps in the mechanism by which SCD increases vaso- occlusion. Our studies show that SCD induces a destructive cycle that is initiated by MPO and propagated by high mobility group box-1 (HMGB1), and one other inflammatory component that alters pulmonary physiology, impairs vascular function, and increases vasocongestion. Previously, we reported L-acetyl-lysyltyrosylcysteine amide (KYC) inhibits MPO, improves vascular function and reduces liver injury induced by excessive vasocongestion in SCD mice. New studies suggest that KYC not only reduces sickle RBC (sRBC) congestion but also increases the number of round sRBC in the lungs of SCD mice. Mechanistic studies reveal that KYC isn't just an inhibitor of MPO toxic oxidant production, but rather, is a unique tripeptide substrate that exploits MPO peroxidase activity to be converted into a novel anti-inflammatory agent that inactivates HMGB1 and activates the cellular pathways that are responsible for antioxidant defense enzyme expression in the lung. As KYC inhibits multiple inflammatory components in our hypothesized destructive cycle, and even activates a component that mediates antioxidant gene expression, new studies using mechanistic inhibitors are required for determine which components increase vasculopathy and vasocongestion in SCD. While a systems pharmaceutical agent may be useful for treating multifactorial diseases, they cannot be used to identify causal mechanisms directly. In this revised application, we hypothesize that SCD induces a destructive cycle, mediated by at least three major components. Our working hypothesis is SCD induces a destructive cycle that is composed of MPO, HMGB1 and a novel, dysregulate gene and together induce vasculopathy and increase vasocongestion. By treating sickle mice, sickle MPO knockout (ko) mice, chimeric sickle Tamoxifen- inducible HMGB1 ko mice and another chimeric sickle ko mice with highly selective mechanistic inhibitors we will be able to determine if and the extent to which MPO, HMGB1 and the third gene product, alone and/or in combination induces vasculopathy and increases vasocongestion. To assess vasculopathy, we will quantify differences in pulmonary artery relaxation, pulmonary permeability, sRBC vasocongestion, and susceptibility of each mouse strain to sRBC vasocongestion induced by hypoxia-reoxygenation injury (HRI) in Townes homozygote sickle Hb (SS) wt SS Mpo ko mice, and chimeric SS novel gene ko mice. Our long-term goals are to confirm the identities of each component and develop novel therapies aimed at improving vascular function and reducing sRBC vasocongestion.