Marijuana smoke promotes dysfunctional macrophage responses to HIV and pneumonia

描述（由申请人提供）：虽然吸烟率正在下降，但大麻的使用频率正在上升，特别是在HIV-1风险人群中。在这种情况下，确定吸食大麻是否与不良健康影响有关是很重要的。大麻素在体外和动物模型中测试时已知可以调节免疫功能。然而，这些影响在大麻吸烟者身上发生的程度及其功能后果尚不清楚。流行病学数据不同地确定大麻使用是艾滋病毒和肺炎的危险因素，我们的研究表明，从大麻吸烟者的肺部恢复的肺泡巨噬细胞（AM）功能受损。然而，关于吸食大麻对全身免疫功能影响的研究并没有显示出明显的缺陷。肺部和全身发现之间的差异使我们假设，对大麻吸烟的局部反应发生在肺部，这是由于暴露于高浓度的局部四氢大麻酚，并使AM功能沿着不能充分保护免受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将确定大麻烟雾所传递的四氢大麻酚是否对AM功能产生局部影响，在对血液单核细胞没有影响的情况下，并确定被破坏的特定宿主防御途径。将对大麻吸烟者和对照组（包括非吸烟者和吸烟者）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。这些细胞将在基线和toll样受体配体挑战时进行评估，以确定大麻使用对受体表达、信号通路和单核细胞和巨噬细胞宿主防御的效应机制的影响。四氢大麻酚和大麻素受体在体外介导这些作用中的直接作用将被研究。目的2将研究慢性大麻使用对AM对HIV感染易感性的影响。将从习惯吸食大麻的人身上获得的AM与对照组的AM进行比较，以了解他们对HIV感染的易感性，并测试他们将HIV传播到自身T细胞的能力，将评估大麻吸烟者改变的效应通路在病毒易感性、增殖和传播中的作用。目的3将研究慢性大麻吸烟小鼠模型中四氢大麻酚暴露途径（吸烟与全身注射）、局部四氢大麻酚浓度与细菌性肺炎易感性之间的关系。小鼠将暴露于大麻烟雾或腹膜内四氢大麻酚，并调整剂量，使其达到与吸食大麻者相似的血清四氢大麻酚水平。将比较两组治疗组在初始和病毒感染后对金黄色葡萄球菌气管内感染的反应。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有感染艾滋病毒风险的人可能造成的健康后果。

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.