Commensal microbiome impact on CD4 T cell lymphopenia in HIV-1 infection

项目总结/摘要 HIV感染的免疫无应答者（INR）的合并症和死亡率的风险高于 在抗逆转录病毒治疗（ART）后恢复其CD4 T细胞计数（IR）的免疫应答者（IR）。INR CD4 T细胞计数低（<350 c/ul），全身炎症加剧，CD4 T细胞循环增加 (KI67+).我们先前报道了通过转录组学和流式细胞术检测INR CD4 T细胞中功能障碍的线粒体。 细胞计数测定。在这里，我们报告了分类记忆CD3 + CD4 + CD45RO + T细胞的代谢谱 来自健康对照（HC）、IR和INR，发现三羧酸循环（TCA）失调 通过电子显微镜成像（EMI）证实了提示线粒体功能障碍的中间体。 高尔基体结构破坏，线粒体数量减少，线粒体嵴不活跃， 在INR EMI切片中检测到线粒体自噬。我们报告了一个新的观察结果，记忆性CD4 T细胞和 富集来自几个群组的INR血浆样品的肠源性细菌毒素p的水平， 甲酚-硫酸盐（PCS）和吲哚酚硫酸盐（IS），两者均与CD4 T细胞计数负相关。孵育 来自具有PCS或IS的HC的外周血单核细胞（PBMC）在体外阻断CD4 T细胞增殖， 诱导细胞凋亡，并减少线粒体蛋白（COX-IV和mTFA）的表达。EMI 揭示了线粒体网络的扰动类似于在INR中发现的那些， 来自HC伴PCS或IS的记忆性CD4 T细胞表明PCS和IS可能有助于减少 INR CD4 T细胞的线粒体适应性。用细菌16S rDNA分析发现INR粪便富集 与代谢酪氨酸的蛋白水解细菌属（双歧杆菌属、瘤胃球菌属、乳杆菌属） 和苯丙氨酸氨基酸来生产PCS。我们认为肠道细菌植物群毒素可能会损害CD 4 ART期间T细胞恢复，可能导致INR特征性的CD4 T细胞淋巴细胞减少症。我们 提出，从机制上讲，PCS/IS诱导对线粒体网络的毒性，然后线粒体DNA被 在细胞质中释放并激活STING，STING触发线粒体死亡途径的半胱天冬酶，IRF3， 和干扰素敏感反应元件（ISRE）基因参与细胞凋亡和细胞凋亡诱导 （目标1）。我们将讨论在一个大的INR队列中血浆PCS/IS的富集是否与低INR相关。 一组离体实验中的CD4 T细胞计数、凋亡/STING水平和线粒体功能障碍 （AIM 2）。然后，我们将通过进行宏基因组学、元蛋白质组学和代谢分析， INR受试者肠道中的肠道细菌是否处于生态失调并富集细菌菌株 过量生产PCS和IS（AIM 3）。

Project Summary/Abstract HIV-infected Immune non-responders (INR) persons are at greater risk of comorbidity and mortality than are immune responders (IR) who restore their CD4 T cells count (IR) after anti- retroviral therapy (ART). INR have low CD4 T cell counts (<350 c/ul), heightened systemic inflammation, and increased CD4 T cell cycling (KI67+). We previously reported dysfunctional mitochondria in INR CD4 T cells by transcriptomic and flow cytometric assays. In here we report the metabolic profiles of sorted memory CD3+CD4+CD45RO+T cells from healthy controls (HC), IR, and INR and found dysregulation of the tricarboxylic acid cycle (TCA) intermediates suggestive of mitochondrial dysfunction confirmed by Electron Microscopy Imaging (EMI). Disrupted Golgi structure, reduced mitochondrial numbers, inactive mitochondrial cristae, and evidence of mitophagy were detected in INR EMI sections. We report the novel observation that memory CD4 T cells and plasma samples of INR from several cohorts are enriched for levels of the gut-derived bacterial toxins p- cresol-sulfate (PCS) and indoxyl sulfate (IS) that both negatively correlate with CD4 T cell counts. Incubation of peripheral blood mononuclear cells (PBMCs) from HC with PCS or IS blocks CD4 T cell proliferation in vitro, induces apoptosis, and diminishes the expression of the mitochondrial proteins (COX-IV and mTFA). EMI reveals perturbations of mitochondria network similar to those found in INR following incubation of sorted memory CD4 T cells from HC with PCS or IS suggesting that PCS and IS may contribute to the diminished mitochondrial fitness of INR CD4 T cells. Using bacterial 16S rDNA assay INR stool were found enriched with proteolytic bacterial genera (Bifidobacterium, Ruminococcus, Lactobacillus) that metabolize tyrosine and phenylalanine amino acids to produce PCS. We propose that gut bacterial flora toxins may impair CD4 T cell recovery during ART and may contribute to CD4 T cell lymphopenia characteristic of INR. We propose, mechanistically, that PCS/IS induce toxicity to the mitochondrial network, mitochondrial DNA is then released in the cytosol and activates STING that triggers caspases of the mitochondrial death pathway, IRF3, and Interferon-Sensitive- Response Element (ISRE) genes implicated in apoptosis and pyroptosis induction (AIM1). We will address whether enrichment of plasma PCS/IS in a large cohort of INR is correlated to low CD4 T cell count, apoptosis/STING levels, and mitochondrial dysfunction in a set of ex-vivo experiments (AIM2). We will then explore, by performing metagenomics, metaproteomics, and metabolic analyses, whether commensal bacteria in the gut of INR subjects are in dysbiosis and enriched in bacterial strains overproducing PCS and IS (AIM3).