Anti-Bacterial Innate Responses Enhance Paramyxovirus Replication

描述（由申请人提供）：人类上呼吸道和相关组织拥有多种微生物菌群。越来越多的证据表明，涉及细菌和副粘病毒的多微生物感染是人类慢性支气管炎、鼻窦炎和中耳炎患者的一个重要因素。复发性中耳炎的后遗症包括听力和语言障碍，严重影响儿童及其父母/照顾者的生活质量。因此，我们对病毒和细菌感染之间的相互作用以及这些微生物对免疫反应的影响的理解存在差距。传统上，TLR信号通路被归类为抗微生物，因为在大多数情况下，它们的激活会导致先天免疫反应并限制细菌或病毒的生长。这一应用是基于我们的显著发现，暴露于原代人单核细胞来源的细胞细菌Toll样受体（TLR）激动剂导致：1)增强副粘病毒基因表达和2)逆转病毒诱导的细胞凋亡。我们提出，细菌成分激活TLR通路并不总是导致严格的抗微生物反应，而是实际上可以创造增强病毒复制的细胞环境。这里要测试的中心假设是，细菌衍生的TLR激动剂通过i)激活细胞存活/增殖途径，或ii)抑制抗病毒途径来增强RNA病毒复制。在Aim 1中，我们将测试细菌成分增强副粘病毒基因表达和挽救病毒诱导的细胞凋亡的两种机制假设。在Aim 2中，我们将扩展这些研究，以确定我们的初步结果是否适用于其他临床相关的RNA病毒，如呼吸道合胞病毒、人副流感病毒、人偏肺病毒、流感病毒和鼻病毒。在Aim 3中，我们将用不可分型的流感嗜血杆菌（NTHi）或肺炎链球菌（肺炎球菌）建立体外细菌生物膜，并确定暴露于细菌生物膜或生物膜衍生成分的免疫细胞和上皮细胞中的病毒复制潜力。我们的研究是创新的，因为它们表明，“抗微生物”信号实际上可以创造促进病毒复制的环境，特别是对于病毒突变体，否则将受到限制。在这个项目完成后，我们将建立一个坚实的基线来研究细菌、病毒和宿主细胞信号通路之间的相互作用，这些信号通路可以调节它们的复制潜力。公共卫生相关性：越来越多的证据表明，涉及细菌和副粘病毒的多微生物感染是人类慢性支气管炎、鼻窦炎和中耳炎患者的一个重要因素，而复发性中耳炎的后遗症可包括听力和语言障碍。我们将验证细菌衍生的TLR激动剂通过i)激活细胞存活/增殖途径或ii)抑制抗病毒途径增强RNA病毒复制的假设。我们的研究是创新的，因为它们表明，“抗微生物”信号实际上可以创造促进病毒复制的环境，特别是对于病毒突变体，否则将受到限制。

DESCRIPTION (provided by applicant): The human upper airway and associated tissues harbor a diverse microbial flora. There is increasing evidence that polymicrobial infections involving bacteria and paramyxoviruses are a significant factor in human patients with chronic bronchitis, sinusitis and otitis media. Sequelae of recurrent otitis media include hearing and speech impairment that significantly impact the quality of life of both children and their parents/caregivers. Thus, there is a gap in our understanding of interactions between viral and bacterial infections as well as the impact of these microbes on immune responses. Traditionally, TLR signaling pathways have been categorized as anti-microbial, since in most cases their activation leads to innate immune responses and to restricted bacterial or viral growth. This application is based on our remarkable finding that exposure of primary human monocyte-derived cells to bacterial Toll- like receptor (TLR) agonists leads to: 1) enhanced paramyxovirus gene expression and 2) a reversal of virus-induced apoptosis. We propose that activation of TLR pathways by bacterial components does not always lead to strictly anti-microbial responses, but rather, can actually create cell environments that enhance virus replication. The central hypotheses to be tested here are that bacterially-derived TLR agonists enhance RNA virus replication through i) activation of cell survival/proliferation pathways, or ii) suppression of antiviral pathways. In Aim 1, we will test these two mechanistic hypotheses by which bacterial components enhance paramyxovirus gene expression and rescue virus-induced apoptosis. In Aim 2, we will extend these studies to determine if our preliminary results apply to other clinically-relevant RNA viruses such as respiratory syncytial virus, human parainfluenza virus, human metapneumovirus, influenza virus, and rhinovirus. In Aim 3, we will establish in vitro bacterial biofilms with nontypeable Haemophilus influenzae (NTHi) or with Streptococcus pneumoniae (pneumococcus) and determine the viral replication potential in immune and epithelial cells exposed to bacterial biofilms or biofilm-derived components. Our studies are innovative, as they show that "anti-microbial" signaling can actually create environments that promote virus replication, particularly for viral mutants which would otherwise be restricted. At the completion of this project, we will have established a firm baseline to study interactions between bacteria, viruses and the host cell signaling pathways that can modulate their replication potential. PUBLIC HEALTH RELEVANCE: There is increasing evidence that polymicrobial infections involving bacteria and paramyxoviruses are a significant factor in human patients with chronic bronchitis, sinusitis and otitis media, and the sequelae of recurrent otitis media can include hearing and speech impairment. We will test the hypotheses that bacterially-derived TLR agonists enhance RNA virus replication through i) activation of cell survival/proliferation pathways, or ii) suppression of antiviral pathways. Our studies are innovative, as they show that "anti-microbial" signaling can actually create environments that promote virus replication, particularly for viral mutants which would otherwise be restricted.