Impact of therapeutic α4β7 integrin inhibition on in vivo monocyte homing and intestinal wound healing in inflammatory bowel diseases

治疗性α4β7 整合素抑制对炎症性肠病体内单核细胞归巢和肠道伤口愈合的影响

• 批准号: 411013818
• 负责人: Professor Dr. Sebastian Zundler
• 金额: --
• 依托单位: Medizinische Klinik 1 - Gastroenterologie, Pneumologie und Endokrinologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/411013818?language=en
• 关键词: Impact; therapeutic; integrin; inhibition; vivo

Inhibition of lymphocyte gut homing with antibodies to α4β7 integrin is a novel mainstay in the therapy of inflammatory bowel diseases (IBD). However, mechanistic investigations have so far focused on lymphocytes and ignored a potential impact on monocyte homing, although monocytes and macrophages as their descendants play a crucial role in the pathogenesis of IBD. Moreover, macrophages are essential for wound healing, which is important in IBD both to bridge disease-inherent mucosal defects and to close wounds arising from disease-associated surgery. Our preliminary data show that α4β7 is differentially expressed on human monocytes with a predominant expression in non-classical monocytes, which preferentially develop to M2-like macrophages. Moreover, we could show that α4β7 is functionally relevant since dynamic adhesion of human monocytes to the addressin MAdCAM-1 is inhibited by the clinically used anti-α4β7 antibody vedolizumab.In the light of a recent report suggesting that wound healing after surgery is impaired in vedolizumab-treated patients, this leads us to postulate that anti-α4β7 treatment impairs homing of non-classical monocytes leading to reduced intestinal numbers of M2-like macrophages and reduced promotion of tissue regeneration. Indeed, preliminary experiments in mice showed that anti-α4β7 treatment inhibited both non-classical monocyte homing and intestinal wound healing in vivo going along with a lower level of M2-like macrophages. Thus, the central hypothesis of this project is that specific monocyte subsets use different gut homing pathways and that these monocyte subsets develop into different intestinal macrophage subsets with different contribution to homeostasis, inflammation and wound healing. Therefore, the aim of this project is to investigate integrin-dependent monocyte gut homing and its functional consequences in detail. To this end we will characterize integrin expression profiles on murine peripheral blood monocytes and intestinal macrophages in steady-state and DSS colitis. Furthermore, we will study the regulation of integrin expression and macrophage differentiation in vitro. We will also analyze the relevance of the monocyte integrins in functional in vitro assays and in an in vivo model of gut homing including intravital microscopy. To assess intestinal wound healing we will make use of an in vivo intestinal wound healing model and evaluate the role of α4β7-mediated monocyte homing and M2-like macrophages. Finally, in a translational approach, we will study shifts in monocyte and macrophage populations in vedolizumab-treated patients and assess the impact of human macrophages on intestinal wound healing in co-culture models. Taken together, this project will help to further shape our pathogenetic concepts of IBD and might lead to the identification of potential future targets for therapy as well as the elucidation of the mechanisms of action and clinical consequences of existing anti-adhesion therapies.

用α4β7整合素抗体抑制淋巴细胞肠道归巢是治疗炎症性肠病（IBD）的新支柱。然而，迄今为止，机制研究集中在淋巴细胞上，而忽略了对单核细胞归巢的潜在影响，尽管单核细胞和巨噬细胞作为其后代在IBD的发病机制中起着至关重要的作用。此外，巨噬细胞对于伤口愈合是必不可少的，这在IBD中对于桥接疾病固有的粘膜缺陷和闭合由疾病相关手术引起的伤口都是重要的。我们的初步数据显示，α4β7在人单核细胞上差异表达，在非经典单核细胞中主要表达，其优先发育为M2样巨噬细胞。此外，我们可以证明α4β7在功能上是相关的，因为临床使用的抗α4β7抗体Vedolizumab抑制了人单核细胞与地址素MAdCAM-1的动态粘附。根据最近的一份报告，表明Vedolizumab治疗的患者术后伤口愈合受损，这使我们假设抗α4β7治疗损害非经典单核细胞的归巢，导致肠道M2-如巨噬细胞和减少促进组织再生。事实上，小鼠中的初步实验显示，抗α4β7治疗抑制体内非经典单核细胞归巢和肠伤口愈合，并伴随沿着较低水平的M2样巨噬细胞。因此，该项目的中心假设是，特定的单核细胞亚群使用不同的肠道归巢途径，并且这些单核细胞亚群发育成不同的肠道巨噬细胞亚群，对稳态、炎症和伤口愈合具有不同的贡献。因此，本项目的目的是详细研究整合素依赖的单核细胞肠道归巢及其功能后果。为此，我们将在稳态和DSS结肠炎中表征小鼠外周血单核细胞和肠巨噬细胞上的整合素表达谱。此外，我们还将在体外研究整合素表达和巨噬细胞分化的调控。我们还将分析单核细胞整合素在体外功能测定和体内肠道归巢模型（包括活体显微镜）中的相关性。为了评估肠伤口愈合，我们将使用体内肠伤口愈合模型并评价α4β7介导的单核细胞归巢和M2样巨噬细胞的作用。最后，在转化方法中，我们将研究Vedolizumab治疗患者中单核细胞和巨噬细胞群的变化，并评估人巨噬细胞对共培养模型中肠伤口愈合的影响。总之，该项目将有助于进一步塑造我们对IBD的致病概念，并可能导致识别潜在的未来治疗靶点，以及阐明现有抗粘连疗法的作用机制和临床后果。