Adenosine, Toll-Like Receptors and Angiogenesis

描述（由申请人提供）：巨噬细胞介导愈合伤口中的炎症和血管生成。我们已经发现了一种新的途径，将巨噬细胞从M1（产生炎症细胞因子，如TNF 1）转换为M2样表型（产生VEGF）。该途径涉及TLR 2、4、7或9与腺苷A2 A受体（A2 AR）信号传导的协同相互作用。TLR激动剂上调A2 AR表达。A2 AR激动剂然后上调HIF 11-I.1 mRNA水平，导致VEGF表达的强烈转录上调。缺乏A2 AR的小鼠伤口愈合受损，缺乏MyD 88的小鼠也是如此，MyD 88是TLR信号传导的关键介质。MyD 88-/-小鼠也不能响应A2 AR激动剂的刺激作用。在这个应用程序中，我们将研究：1。TLR激动剂对A2 AR表达的调节：将研究TLR激动剂是否在转录上诱导A2 AR表达。将测试LPS处理的巨噬细胞对A2 AR活化的响应性增加是由于A2 AR水平增加还是由于脱敏抑制导致的A2 AR响应性增加。还将确定LPS诱导的A2 AR mRNA的特异性亚型。2.体内巨噬细胞的A2 AR表达：为了确定A2 AR表达是否在体内上调，将在损伤后的不同时间点从愈合伤口分离巨噬细胞，并检查它们的A2 AR表达。将检查Ly-6Chi和Ly-6Clo巨噬细胞亚群及其A2 AR的表达。3.巨噬细胞与内皮细胞A2 AR表达在伤口愈合中的作用：A2 AR- /-小鼠愈合不良，肉芽组织形成减少。我们将从A2 AR-/-小鼠移植骨髓到辐射的A2 AR +/+小鼠（反之亦然），以确定骨髓细胞A2 AR表达在伤口愈合中的作用。为了避免辐射引起的潜在并发症，将使用Cre-Lox技术培育骨髓细胞中特异性缺失A2 AR的小鼠。还将研究使用Tie 2-Cre小鼠培育的A2 AR内皮细胞缺失的小鼠。由于这些小鼠在内皮细胞和造血细胞中均缺失A2 AR，因此将用野生型小鼠（UbC-GFP小鼠）的骨髓进行重建。4.巨噬细胞HIF 11-I.1同种型在伤口愈合中的作用：HIF 11-I.1是巨噬细胞中TLR-A2 AR活化诱导的主要同种型.首先研究具有HIF 11-I.1同种型（HIF 11-I.1-/-）的整体敲除的小鼠。为了确定巨噬细胞表达的HIF 11-I.I的作用，然后将研究用野生型骨髓移植的HIF 11-I. 1-/-小鼠，反之亦然。然后将研究骨髓细胞中特异性敲除HIF 11-I.1的小鼠，所述小鼠通过使具有floxed HIF 11-I.1的小鼠与LysM-Cre小鼠交配而获得。这些研究将为巨噬细胞A2 AR表达的调节提供有价值的见解，并进一步阐明巨噬细胞表型中TLR-A2 AR依赖性开关在体内炎症和伤口愈合调节中的作用。公共卫生相关性：巨噬细胞是调节伤口愈合、炎性纤维增生性疾病和癌症中的炎症和血管生成的关键细胞。我们发现了一种调节巨噬细胞功能的新途径，该途径需要两种不同受体类型（即Toll样受体（TLR）和腺苷A2 A受体）之间的相互作用。该途径将巨噬细胞从炎性表型转换为血管生成的伤口愈合表型。在本申请中，我们建议详细研究TLR在调节A2 AR的表达和功能中的作用，并研究A2 AR信号传导的关键介质，即HIF 11转录因子，特别是HIF 11-I.1亚型的作用。这些因素将在体外和体内伤口愈合模型中进行研究。了解伤口愈合和血管生成的调节途径，应导致确定新的目标，这些过程的药理学调节，从而潜在的疾病，这些过程中发挥关键作用的新疗法。

DESCRIPTION (provided by applicant): Macrophages mediate inflammation and angiogenesis in healing wounds. We have discovered a novel pathway that switches macrophages from an M1 (production of inflammatory cytokines such as TNF1) to an M2-like phenotype (production of VEGF). This pathway involves a synergistic interaction of TLR 2, 4, 7 or 9 and adenosine A2A receptor (A2AR) signaling. TLR agonists up-regulate A2AR expression. A2AR agonists then up-regulate HIF11-I.1 mRNA levels, resulting in strong transcriptional up-regulation of VEGF expression. Mice lacking A2ARs have impaired wound healing, as do mice lacking MyD88, a key mediator of TLR signaling. MyD88-/- mice also fail to respond to the stimulatory effects of A2AR agonists. In this application, we will study: 1. Regulation of A2AR expression by TLR agonists: whether TLR agonists induce A2AR expression transcriptionally will be studied. Whether increased responsiveness of LPS-treated macrophages to A2AR activation is due to increased levels of A2ARs or to increased responsiveness of A2ARs due to inhibition of desensitization will be tested. The specific isoform of A2AR mRNA induced by LPS will also be defined. 2. Expression of A2ARs by macrophages in vivo: To determine if A2AR expression is upregulated in vivo, macrophages will be isolated from healing wounds at various time points following injury, and their expression of A2ARs examined. Ly-6Chi and Ly-6Clo macrophagesub-populations and their expression of A2ARs will be examined. 3. The role of macrophage versus endothelial cell A2AR expression in wound healing: A2AR- /- mice heal poorly, with reduced granulation tissue formation. We will transplant bone marrow from A2AR-/- to irradiated A2AR+/+ mice (and vice versa) to determine the role of myeloid cell A2AR expression in wound healing. To avoid potential complications due to irradiation, mice with A2ARs deleted specifically in myeloid cells using Cre-Lox technology will be bred. Mice with an endothelial cell deletion of A2ARs bred using Tie2-Cre mice will also be studied. As these mice have A2ARs deleted in both endothelial and hematopoietic cells, reconstitution with bone marrow from wild type mice (UbC-GFP mice) will be performed. 4. The role of the macrophage HIF11-I.1 isoform in wound healing: HIF11-I.1 is the predominant isoform induced by TLR- A2ARactivation in macrophages. Mice with global knockout of HIF11-I.1 isoform (HIF11-I.1-/-) will first be studied. To determine the role of HIF11-I.I expressed by macrophages, HIF11-I.1-/- mice transplanted with wild-type bone marrow and vice versa will then be studied. Mice with specific knockout of HIF11-I.1 in myeloid cells, obtained by breeding mice with floxed HIF11-I.1 with LysM-Cre mice, will then be studied. These studies should provide valuable insights into the regulation of A2AR expression by macrophages, and throw further light on the role of the TLR-A2AR-dependent switch in macrophage phenotype in the regulation of inflammation and wound healing in vivo. PUBLIC HEALTH RELEVANCE:: Macrophages are key cells that regulate inflammation and angiogenesis in wound healing, inflammatory fibroproliferative diseases and cancer. We have discovered a novel pathway that regulates macrophage function that requires an interaction between two disparate receptor types, namely Toll-like receptors (TLRs) and adenosine A2A receptors. This pathway switches macrophages from an inflammatory to an angiogenic, wound healing phenotype. In this application, we propose to study in detail the role of TLRs in regulating the expression and function of A2ARs, and to study the role of a key mediator of A2AR signaling, namely the HIF11 transcription factor and in particular, the HIF11-I.1 isoform. These factors will be studied both in vitro, and in vivo in models of wound healing. Understanding the pathways by which wound healing and angiogenesis are regulated should lead to the identification of novel targets for the pharmacological regulation of these processes, and thus potentially to novel therapies for diseases where these processes play a key role.