Marijuana smoke promotes dysfunctional macrophage responses to HIV and pneumonia

描述（由申请人提供）：虽然吸烟率在下降，大麻使用的频率在上升，特别是在HIV-1高危人群中。在这种情况下，重要的是要确定吸食大麻是否与不良健康影响有关。已知大麻素在体外和动物模型中测试时可调节免疫功能。然而，这些影响在大麻吸食者中发生的程度及其功能后果尚不清楚。流行病学数据证实大麻使用是艾滋病毒和肺炎的一个危险因素，我们的研究表明，从大麻吸烟者肺部回收的肺泡巨噬细胞（AM）功能受损。然而，研究大麻吸烟对全身免疫功能的影响并没有表现出明显的缺陷。肺部和全身发现之间的这种差异使我们假设，对大麻吸烟的局部反应发生在肺中，由暴露于高局部浓度的THC引起，并使AM功能沿不能充分保护免受HIV感染或肺炎的途径极化。这项拨款提出了三个具体目标：目标1将确定大麻烟雾提供的THC是否对AM功能产生局部影响，在不影响血液单核细胞的情况下，并确定被破坏的特定宿主防御途径。将对一组大麻吸烟者和对照组（非吸烟者和吸烟者）进行支气管肺泡灌洗和外周血取样，以获得纯化的AM和单核细胞。这些细胞将在基线时进行评估，并在用toll样受体配体进行挑战时进行评估，以确定大麻使用对其受体表达，信号传导途径和单核细胞和巨噬细胞宿主防御中涉及的效应机制的影响。将在体外研究THC和大麻素受体在介导这些效应中的直接作用。目的2探讨长期吸食大麻对AM感染HIV易感性的影响。将从习惯性大麻吸烟者获得的AM与来自对照的AM进行比较，以确定其对HIV感染的易感性，并测试其将HIV传递至自体T细胞的能力。将评估大麻吸烟者中改变的效应子途径在病毒易感性、增殖和传播中的作用。目标3将研究THC暴露途径（吸烟与全身注射），局部THC浓度和慢性大麻吸烟小鼠模型中细菌性肺炎易感性之间的关系。将小鼠暴露于大麻烟或腹膜内THC，并调整剂量以达到与大麻吸烟者相似的血清THC水平。将比较处理组对S.金黄色葡萄球菌在初始和病毒感染后的条件下。大麻素受体的作用将使用受体敲除菌株进行评估。通过这些研究的结论，我们将更清楚地了解大麻相关的毒性及其对大麻吸烟者和艾滋病毒高危人群健康相关后果的潜在影响。

DESCRIPTION (provided by applicant): While the rates of tobacco smoking are on the decline, the frequency of marijuana use is rising and especially high among individuals at risk for HIV-1. In this setting it is important to establish whether marijuana smoking is associated with adverse health effects. Cannabinoids are known to modulate immune function when tested in vitro and in animal models. However, the extent to which these effects occur in marijuana smokers and their functional consequences are not known. Epidemiologic data variably identify marijuana use as a risk factor for HIV and pneumonia and our research has shown that alveolar macrophages (AM) recovered from the lungs of marijuana smokers are functionally impaired. However, studies examining the effects of marijuana smoking on systemic immune function have not demonstrated clear deficiencies. This discrepancy between pulmonary and systemic findings leads us to hypothesize that a localized response to marijuana smoking occurs in the lung, results from exposure to high local concentrations of THC, and polarizes AM function along a pathway that cannot adequately protect against HIV infection or pneumonia. This grant proposes three specific aims: Aim 1 will determine whether THC delivered by marijuana smoke exerts a local effect on AM function, in the absence of effects on blood monocytes, and identify the specific host defense pathways that are disrupted. Broncho- alveolar lavage and peripheral blood sampling will be carried out with a cohort of marijuana smokers and controls (both non-smokers and tobacco smokers) to obtain purified AM and monocytes. These cells will be assessed at baseline and when challenged with a toll-like receptor ligand to determine the impact of marijuana use on their expression of receptors, signaling pathways and effector mechanisms involved in monocyte and macrophage host defense. The direct role of THC and cannabinoid receptors in mediating these effects will be investigated in vitro. Aim 2 will investigate the effects of chronic marijuana use on the susceptibility of AM to HIV infection. AM obtained from habitual marijuana smokers will be compared to those from controls for their susceptibility to HIV infection and tested for their capacity to transmit HIV to autologous T cells Effector pathways that are altered in marijuana smokers will be assessed for their role in viral susceptibility, proliferation and transmission. Aim 3 will examine the relationship between the route of THC exposure (smoking vs. systemic injection), local THC concentrations, and susceptibility to bacterial pneumonia in a mouse model of chronic marijuana smoking. Mice will be exposed to marijuana smoke or to intra-peritoneal THC and dosing adjusted so to achieve serum THC levels similar to those occurring in marijuana smokers. Treatment groups will be compared for their responses to an intra-tracheal challenge with S. aureus under both naive and post- viral conditions. The role of cannabinoid receptors will be evaluated using receptor knockout strains. By the conclusion of these studies we will have a much clearer understanding of marijuana-related toxicity and its potential for health-related consequences in marijuana smokers and those at risk for HIV.