Consequences of Chemokine-Receptor Interactions: Immune

我们已经进一步进行了我们的研究，显示参与先天宿主防御的抗微生物肽也与宿主炎性细胞上的受体相互作用，导致适应性免疫应答。人粒细胞源性防御素对静息幼稚T细胞和未成熟树突状细胞具有趋化性。这些研究结果的生理相关性被证明，-防御素共同管理时，在疫苗中作为有效的免疫佐剂，增强体液以及细胞免疫反应，甚至相对较弱的独特型肿瘤抗原从B细胞淋巴瘤。在与由Jacek Lubkowski博士领导的NCI生物药理学家的合作中，上皮细胞衍生的防御素被证明具有类似于趋化因子的三级结构，所述防御素对表达“LARC”的CCR 6受体的未成熟树突状细胞和静息记忆细胞具有趋化性。我们实验室的De Yang和Oleg Chertov博士扩展了这些发现，表明cathelicidin（LL 37）是中性粒细胞和上皮细胞的另一种抗菌产物，也可以通过与FPRL-1受体相互作用动员参与宿主防御的白细胞。此外，经典化学引诱物受体如C5 a、FPR和FPRL-1在未成熟和成熟树突细胞上的表达已被证明进一步理解它们在抗原加工和递送至T细胞以帮助启动免疫应答中的作用。Oleg Chertov博士已经鉴定了中性粒细胞在脱粒过程中释放的组织蛋白酶G作为吞噬细胞的化学引诱物，并且如果与抗原一起施用，则作为疫苗免疫佐剂。 我们已经研究了趋化因子在血管生成中的作用及其对肿瘤进展的贡献。Rosalba萨尔塞多博士表明，人类微血管内皮细胞（HMVEC）比不太成熟的人类脐静脉内皮细胞（HUVEC）表达更多功能性趋化因子受体。这使她能够证明HMVEC表达功能性CCR 2和CCR 3以及CXCR 1 -3，并与趋化因子配体如MCP-1和Eotaxin反应。这些配体在基质胶塞测定中也具有体内血管生成活性。 我们以前报道过，通过与m，d和k阿片样物质（GPCR）受体相互作用，预先暴露于阿片类药物（如内啡肽和吗啡）可以异源脱敏和磷酸化一些趋化因子受体，使它们暂时对这些趋化因子无反应。在与汤姆·罗杰斯博士的合作中，我们可以证明这是一个双向过程。先前暴露于多种趋化因子导致阿片样物质μ受体的脱敏和磷酸化。这可能提供了另一种机制，通过这种机制，来自炎症部位的成对信号被阿片样物质信号的抑制所加重。 对NCI国家产品库中具有抗炎特性的中草药和植物提取物中的成分进行分析，使我们鉴定出许多抑制许多促炎趋化因子的趋化活性的分子实体。鹅去氧胆酸（CDCA）在无毒浓度下选择性地抑制与FPR和FPRL-1相互作用的配体。然而，也已知这些试剂与核受体相互作用，因此抑制细胞因子产生和免疫应答。因此，这些药物也具有抗血管生成作用，我们正在研究它们对SCID小鼠体内肿瘤生长的影响。 与M博士合作。Cushman在印第安纳州大学的研究表明，可莎烷化合物干扰RANTES与CCR 1受体相互作用的能力。这些化合物还具有抗血管生成作用，并正在SCID小鼠的人类肿瘤模型上进行测试。中国抗炎药物中的另一种成分紫草素被发现选择性地干扰CCR 1-配体相互作用。然而，它也通过干扰GPCR启动的信号转导来阻断所有趋化因子的趋化作用。我们目前正在研究这种潜在的强效抗炎和抗血管生成剂的作用机制。

We have further pursued our studies showing that antimicrobial peptides involved in innate host defense also interact with receptors on host inflammatory cells resulting in adaptive immune responses. Human granulocyte derived -defensins are chemotactic for resting naive T cells and immature dendritic cells. The physiological relevance of these findings were documented by showing that the -defensins when coadministered in a vaccine act as potent immunoadjuvant that enhance the humoral as well as cellular immune response even to relatively weak idiotypic tumor antigens from a B cell lymphoma. In collaboration with NCI biophysicists led by Dr. Jacek Lubkowski, the epithelial cell derived -defensins which are chemotactic for immature dendritic cells and resting memory cells that express the CCR6 receptor for "LARC", were shown to have a tertiary structure resembling that of chemokines. Drs. De Yang and Oleg Chertov in our laboratory extended these findings to show that cathelicidin (LL37) another antimicrobial product of both neutrophils and epithelial cells can also mobilize leukocytes engaged in host defense by interacting with the FPRL-1 receptor. Furthermore the expression of classical chemoattractant receptors such as C5a, FPR and FPRL-1 on immature and mature dendritic cells has been demonstrated to further understand their role in the processing and delivery of antigen to T cells to help initiate immune responses. Dr. Oleg Chertov has identified cathepsin G released by neutrophils in the course of degranulation as a chemoattractant of phagocytes and as a vaccine immunoadjuvant if administered together with antigens. We have studied of the role of chemokines in angiogenesis and their contribution to tumor progression. Dr. Rosalba Salcedo showed that human microvascular endothelial cells (HMVEC) express more functional chemokines receptors than the less mature human umbilical vein endothelial cells (HUVEC). This enabled her to show that HMVEC express functional CCR2 and CCR3 as well as CXCR1-3 and react to chemokine ligands such as MCP-1 and Eotaxin. These ligands also have in vivo angiogenic activities in a matrigel plug assay. We previously reported that prior exposure to opiates such as endorphins and morphine by interacting with m,d and k opioid (GPCR) receptors can heterologously desensitize and phosphorylate a number of chemokine receptors, making them temporarily unresponsive to these chemokines. In collaboration with Dr. Tom Rogers we can show that this is a bidirectional process. Prior exposure to a number of chemokines results in the desensitization and phosphoylation of the opioid mu receptor. This may provide another mechanisms by which the pair signals from inflammatory sites are accentuated by suppression of the opioid signals. Analyses of components in Chinese herbal medicines and extracts of plants with purported anti-inflammatory properties available in the National Product Repository of the NCI have led us to identify a number of molecular entities that inhibit the chemotactic activities of a number of proinflammatory chemokines. Chenodeoxycholic acid (CDCA) to a lesser degree deoxyoxycholic acid (CDA) at nontoxic concentrations selectively inhibit ligands interacting with FPR and FPRL-1. However, these agents are also known to interact with nuclear receptors and therefore suppress cytokine production and immune responses. These agents consequently also have anti-angiogenic effects and we are investigating their effects on in vivo tumor growth in SCID mice. In collaboration with Dr. M. Cushman at Indiana University we have shown that cosalane compounds interfere with RANTES capacity to interact with CCR1 receptors. These compounds also have anti-angiogenic effects and are being tested on human tumor models in SCID mice. Another component in Chinese anti-inflammatory medicinals known as shikonin was found to selectively interfere with CCR1-ligand interactions. However, it also blocks the chemotactic effect of all chemokines by interfering with GPCR initiated signal transduction. We are at present studying the mechanism of action of this potentially potent anti-inflammatory and anti angiogenic agent.