Pathogenesis of lung injury mediated by lung-restricted antibodies

项目摘要 针对非多态性肺自身抗原、胶原V型（COLV）和K- α 1微管蛋白（KAT）存在于超过三分之一的接受肺移植的患者中。由于这些自- 抗原在所有人中表达，受体中预先存在的LRA可以结合暴露的同源抗原 在新移植的肺里事实上，上帝军已成为发生冲突的主要风险因素， 原发性移植物功能障碍的发展，肺移植后早期死亡的主要原因。 在小鼠模型中，LRA与严重的同种异体肺移植损伤有因果关系，在患者中， 随着供体特异性同种免疫反应的发展。然而，其背后的机制 致病性尚未阐明。鉴于上帝抵抗军发病率高， 同种异体移植物损伤，阐明这些机制应导致相关的策略，以改善肺移植 生存我们已经报道了LRA介导的同种异体移植物损伤与补体的沉积有关 和中性粒细胞浸润。然而，我们不了解LRA驱动补体的机制， 沉积或中性粒细胞募集，也不是LRA介导的损伤所必需的。由于这些肺 自身抗原位于间质空间，也不清楚循环LRA如何进入这些空间。 抗原我们最近报道，脾来源的Ly 6ChhighCCR 2+经典单核细胞（CM）是一种高分化的细胞。 在缺血-再灌注损伤后，它们被招募到肺中，在那里它们是打开紧密的内皮细胞所必需的 通过激活IL 1 β受体（IL 1 R）来调节连接。与这些发现一致，我们的初步数据显示， 来自IL 1 r-/-供体的同基因或同种异体肺移植物被保护免受LRA介导的肺移植物损伤。我们 还报道了Ly 6ClowCCR 2-肺血管内非经典单核细胞（NCM）是必需的， 中性粒细胞进入供体肺我们新的初步数据表明上帝抵抗军与他们的 同源抗原可以增强中性粒细胞化学引诱物CXCL 2从人和鼠NCM的释放。 因此，我们假设LRA外渗到肺组织需要IL 1 β依赖性的 脾来源的经典单核细胞开放内皮紧密连接， 当抗原在淋巴结中时，交联的LRA激活补体以及供体来源的NCM， 急性肺移植损伤因此，我们将确定：1）脾CM是否允许LRA通过进入 在脾中接受教育后，通过开放内皮紧密连接来改善肺，2）补充途径 负责LRA介导的损伤以及补体激活的机制，以及3）是否 LRA对供体NCM的Toll受体非依赖性活化导致中性粒细胞募集和肺损伤。 这些实验的总体目标是为LRA的生物学提供新的见解，并在临床上引入 通过药理学抑制CM-1抑制移植后肺损伤的适用策略 来源的IL 1 β（Aim 1）、补体（Aim 2）或供体NCM缺失（Aim 3）。

PROJECT SUMMARY Lung-restricted antibodies (LRA) against non-polymorphic lung self-antigens, collagen type V (COLV) and K- alpha1 tubulin (KAT), are present in over a third of patients undergoing lung transplantation. Since these self- antigens are expressed in all humans, pre-existing LRA in the recipient can bind to cognate antigens exposed in the freshly transplanted lungs. Indeed, LRA have emerged as the predominant risk factor for the development of primary graft dysfunction, the principal cause of early mortality following lung transplantation. In murine models, LRA are causally linked to severe lung allograft injury, and in patients they are associated with development of donor specific alloimmune responses. However, the mechanisms underlying their pathogenicity have not been elucidated. Given the high prevalence of LRA and their causal association with allograft injury, delineating these mechanisms should lead to relevant strategies to improve lung transplant survival. We have reported that LRA mediated allograft injury is associated with the deposition of complement and neutrophil infiltration. However, we do not understand the mechanisms by which LRA drive complement deposition or neutrophil recruitment, nor whether either is necessary for LRA-mediated injury. Since these lung self-antigens are located in the interstitial spaces, it is also unclear how circulating LRA gain access to these antigens. We have recently reported that spleen-derived Ly6ChighCCR2+ classical monocytes (CM) are recruited to the lungs following ischemia-reperfusion injury where they are necessary to open endothelial tight junctions by activating IL1β receptors (IL1R). Consistent with these findings, our preliminary data shows that syngeneic or allogeneic lung grafts from Il1r-/- donors are protected from LRA-mediated lung graft injury. We have also reported that Ly6ClowCCR2- pulmonary intravascular non-classical monocytes (NCM) are necessary for neutrophil recruitment into the donor lung. Our new preliminary data suggest that LRA cross-linked to their cognate antigens can enhance release of the neutrophil chemoattractant CXCL2 from human and murine NCM. Therefore, we hypothesize that extravasation of LRA into the lung interstitium requires IL1β-dependent opening of endothelial tight junctions by spleen-derived classical monocytes and, upon binding to cognate antigens in the interstitium, cross-linked LRA activate complement as well as donor-derived NCM to promote acute lung allograft injury. Accordingly, we will determine 1) whether splenic CM allow passage of LRA into the lungs by opening endothelial tight junctions after being educated in the spleen, 2) which complement pathway is responsible for LRA-mediated injury as well as the mechanisms of complement activation, and 3) whether toll-receptor independent activation of donor NCM by LRA leads to neutrophil recruitment and lung injury. Overall goal of these experiments is to provide novel insights into the biology of LRA and introduce clinically applicable strategies to inhibit lung injury following transplantation through pharmacological inhibition of CM- derived IL1β (Aim 1), complement (Aim 2), or deletion of donor NCM (Aim 3).