Innate Immunity, HIV, and OIs: Role of TLRs in the Lung

艾滋病患者的机会性感染(OIS)常发生在肺部。即使在高效抗逆转录病毒疗法(HAART)的时代，这些疾病也会导致相当大的发病率和死亡率。天然免疫系统已被认为是宿主对感染性病原体免疫的重要组成部分，但由于大多数研究集中在获得性免疫系统，因此在HW感染的背景下，这些反应很少受到关注。我们建议研究HIV感染过程中Toll样受体(TLRs)的变化，TLRs是先天免疫反应的中心组成部分。这些研究将使用患者来自肺的样本(肺泡巨噬细胞，AM)来最接近地模拟体内的情况，并使用单母细胞系(U1和U937细胞)来对患者来自的细胞进行建模，并研究这些变化的详细机制。HIV在肺中的作用以及随后肺内免疫效应细胞的功能变化，是目前研究较少的领域。我们的中心假设是，HIV感染会导致TLR表达的改变，导致先天免疫反应不足，从而使患者容易发生OIS。我们的初步数据显示，与HIV对照组相比，HIV受试者AM中TLR2和TLR4的mRNA和蛋白表达减少，以及TNFcx水平(TLR介导的效应功能)降低。我们将研究在HIV感染期间，在HIV和HIV受试者的AM中，以及在U1和U937细胞中，TLRs是否会发生变化 通过测定(I)TLR2(以及与TLR2形成异源二聚体的TLR2和TLR6)和TLR4mRNA和蛋白的表达；(Ii)TLR2和TLR4介导的TNFc_产生；(Iii)TLR途径的磷酸化信号中间体(MyD88、IRAK和PI3‘-K)以及伴随的NF-kB DNA结合活性；以及(Iv)HW-1 gp120或gp160是否直接结合这些TLR或通过间接作用影响TLR2或TLR4的表达。这项赠款的创新是一种新的范式，它建议直接 或艾滋病毒对TLRs的间接影响，可能影响对OIS或艾滋病毒本身的先天免疫反应。

Opportunistic infections (OIs) in patients with AIDS often occur in the lung. These lead to substantial morbidity and mortality, even in the era of highly-active antiretroviral therapy (HAART). The innate immune system has been recognized as an important component of host immunity to infectious pathogens, but these responses have received little attention in the setting of HW infection, since most studies have focused on the adaptive immune system. We propose to study alterations in Toll-like receptors (TLRs), a central component of innate immune responses, during HIV infection. These studies will use patient-derived samples from the lung (alveolar macrophages, AMs) to most closely mimic the in vivo situation, and monoblastoid cell lines (U1 and U937 cells) to model the patient-derived cells and study the detailed mechanisms of these alterations. The effects of HIV in the lung and subsequent functional alterations of immune effector cells in the lung, are understudied areas. Our central hypothesis is that HIV infection causes alterations in TLR expression that lead to deficient innate immune responses, which predispose patients to OIs. We have preliminary data showing decreased TLR2 and TLR4 mRNA and protein expression, and decreased TNFcx levels (a TLR-mediated effector function) in AMs from HIV+ subjects compared to HIV- controls. We will study whether TLRs are altered during HIV infection, in AMs from HIV+ and HIV- subjects, and in U1 and U937 cells, using relevant TLR2 and TLR4 hgands, by determining (i) TLR2 (and TLR1 and TLR6, which form heterodimers with TLR2) and TLR4 mRNA and protein expression; (ii) TLR2- and TLR4-mediated TNFc_ production; (iii) phosphorylated signaling intermediaries of the TLR pathway (MyD88, IRAK, and PI3'-kinase), and concomitant NF-kB DNA-binding activity; and (iv) if HW-1 gp120 or gp160 affect TLR2 or TLR4 expression, either by directly binding to these TLR, or through indirect effects. The innovation of this grant is a new paradigm that suggests direct or indirect effects of HIV on TLRs that may affect innate immune responses to OIs or HIV, itself.