Mechanisms of HIV-associated epithelialintestinal stem cell (ISC) dysfunction

HIV相关上皮肠干细胞（ISC）功能障碍的机制

• 批准号: 10661656
• 负责人: Henrik Kloverpris
• 金额: $ 71.25万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10661656
• 关键词: Address; Africa South of the Sahara; Apoptosis; Area; Bacteria; Biological Markers; Biological Models; Biopsy; Biopsy Specimen; Blood; CD4 Positive T Lymphocytes; Cell physiology; Cells; Cessation of life; Chronic; Circulation; Colon; Data; Defect; Development; Disease; Disease Progression; Duodenum; Epithelial Cells; Epithelium; Functional disorder; Gastrointestinal tract structure; Genetic Transcription; HIV; HIV Infections; Health; Heart Diseases; Histology; Homeostasis; Hospitals; Human; Hyperglycemia; IL17 gene; Immune; Immune System Diseases; Immunology; Impairment; In Situ; Incidence; Individual; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Injury; Intercellular Junctions; Interferon Type I; Interferon Type II; Interleukin-10; Interleukin-13; Intestinal Mucosa; Intestinal permeability; Intestines; Knowledge; MHC Class II Genes; Massachusetts; Mediating; Modeling; Molecular; Morbidity - disease rate; Mucous Membrane; Mus; Organoids; Outcome; Pathogenesis; Pathologist; Pathology; Pathway interactions; Peripheral; Permeability; Persons; Phenotype; Population; Positioning Attribute; Prevalence; Process; Production; Proliferating; Regimen; Reporting; Role; Sampling; Signal Pathway; Signal Transduction; Site; South Africa; Stroke; System; T-Cell Depletion; T-Lymphocyte; Techniques; Technology; Testing; Tissue Sample; Tissues; Viral Load result; Virus Replication; antiretroviral therapy; cohort; cytokine; epithelial repair; epithelium regeneration; exhaustion; experience; gastrointestinal; gastrointestinal epithelium; graft vs host disease; gut bacteria; gut dysbiosis; gut inflammation; immune activation; improved; in vivo; interleukin-22; intestinal barrier; intestinal epithelium; microbial; microbial products; mortality; mouse model; novel therapeutic intervention; protein expression; response; self-renewal; stem cell biology; stem cell differentiation; stem cell function; stem cell proliferation; stem cells; systemic inflammatory response

SUMMARY The gastrointestinal (GI) tract is a major site of Human Immunodeficiency Virus (HIV) replication, which leads to intestinal inflammation, CD4+ T cell depletion and gut epithelial barrier dysfunction. These defects are thought to drive HIV disease progression by allowing translocation of luminal microbial products into the circulation, which triggers chronic systemic immune activation and disease progression. Although antiretroviral therapy (ART) effectively suppress viral replication in the blood, it does not restore CD4+ T cell levels in the gut; even individuals with suppressed viral loads for decades have persistent gut barrier impairment and continued microbial translocation. Epithelial intestinal stem cells (ISCs) are responsible for replenishing the intestinal epithelium during normal homeostatic turnover and orchestrating epithelial repair following injury. Current studies of intestinal epithelial dysfunction in HIV are limited and have relied primarily on correlative observations based on histology or peripheral biomarkers. Our proposal addresses critical gaps in knowledge by 1) performing in-depth characterization of ISC proliferation, self-renewal and differentiation ex vivo and in vivo in HIV-infected and uninfected individuals; 2) utilizing tissue samples from a unique cohort of individuals in sub-Saharan Africa, where HIV burden is highest and most devastating; 3) applying cutting-edge techniques to uncover molecular signalling pathways involved in HIV-induced epithelial dysfunction; and 4) thoroughly testing mechanistic hypotheses using relevant mouse models and ex vivo organoid culture systems. With our combined expertise in HIV disease, mucosal immunology and GI pathology, we are well positioned to uncover specific mechanisms that underlie intestinal epithelial dysfunction in HIV infection. An understanding of these mechanisms is critical to facilitate development of novel therapeutic approaches to improve health outcomes of people living with HIV. In this proposal, we hypothesize that HIV infection results in hyperproliferation of ISCs, aberrant ISC differentiation, increase epithelial death, and dysfunction of epithelial cellular junction integrity. Additionally, based upon our data, we hypothesize that this HIV-associated ISC dysfunction can occur via two mechanisms: 1) depletion of intestinal CD4+ T cells and loss of specific T helper cytokines that promote intestinal epithelial homeostasis and 2) type I and II interferon signalling within ISCs in HIV-infected individuals. To address these hypotheses we are proposing two complementary aims. Aim 1 will use state-of-the-art technologies to characterise ISC function directly ex vivo in gut pinch biopsies sampled throughout the intestinal mucosa from our established cohort at Albert Luthuli Central Hospital in Durban, South Africa. In Aim 2 will use in vivo mouse models of CD4+ T cell depletion and examine the impact on ISC proliferation, self-renewal and differentiation, and use ex vivo human organoid models to study the impact of type I and II interferon pathways on ISC function. This proposal will address important unknown mechanisms of ISC biology that may help in the development of new strategies to reverse gut barrier defects in HIV infection.

概括 胃肠道（GI）道是人类免疫缺陷病毒（HIV）复制的主要部位，导致 肠炎，CD4+ T细胞耗竭和肠道上皮屏障功能障碍。这些缺陷被认为 通过允许将腔微生物产物易位到循环中来推动艾滋病毒疾病进展 触发慢性全身免疫激活和疾病进展。虽然抗逆转录病毒疗法（ART） 有效地抑制血液中的病毒复制，它不会恢复肠道中的CD4+ T细胞水平。甚至个人 数十年来抑制病毒负荷有持续的肠道障碍和持续的微生物 易位。上皮肠干细胞（ISC）负责补充肠上皮 在正常的稳态周转期间，受伤后修复上皮修复。当前的研究 HIV中的肠上皮功能障碍受到限制，主要依赖于基于相关性观察 组织学或周围生物标志物。我们的提议解决了知识中的关键差距1）深入执行 ISC增殖，自我更新和分化的体内和体内的特征 未感染的人； 2）利用来自撒哈拉以南非洲独特个体的组织样品， 艾滋病毒负担最高和最毁灭性的地方； 3）应用尖端技术来发现分子 涉及HIV引起的上皮功能障碍的信号通路； 4）彻底测试机制 使用相关的小鼠模型和离体器官培养系统的假设。凭借我们的联合专业知识 艾滋病毒疾病，粘膜免疫学和胃肠道病理学，我们有好处发现特定机制 这是HIV感染中肠上皮功能障碍的基础。对这些机制的理解至关重要 促进新型治疗方法的发展，以改善艾滋病毒患者的健康状况。 在此提案中，我们假设HIV感染导致ISC的过度增殖，ISC异常 分化，增加上皮死亡以及上皮细胞完整性的功能障碍。此外， 根据我们的数据，我们假设这种与HIV相关的ISC功能障碍可以通过两种机制发生： 1）肠道CD4+ T细胞的消耗以及促进肠上皮的特定T辅助细胞因子的丧失 稳态和2）I型和II型干扰素信号在HIV感染者中的ISC中。解决这些 假设我们提出了两个补充目标。 AIM 1将使用最先进的技术来 在整个肠道粘膜中取样的肠捏活活检中的ISC函数直接在肠道粘膜中直接表征。 我们在南非德班的Albert Luthuli中央医院成立的队列。在AIM 2中将使用体内鼠标 CD4+ T细胞耗竭的模型，并检查对ISC增殖，自我更新和分化的影响， 并使用离体人体器官模型研究I型和II型干扰素途径对ISC功能的影响。 该提案将解决ISC生物学重要的未知机制，这可能有助于发展 逆转肠道屏障缺陷的新策略。

项目成果

Irreversible depletion of intestinal CD4+ T cells is associated with T cell activation during chronic HIV infection.

• DOI: 10.1172/jci.insight.146162
• 发表时间: 2021-11-22
• 期刊: JCI insight
• 影响因子: 8
• 作者: Asowata OE;Singh A;Ngoepe A;Herbert N;Fardoos R;Reddy K;Zungu Y;Nene F;Mthabela N;Ramjit D;Karim F;Govender K;Ndung'u T;Porterfield JZ;Adamson JH;Madela FG;Manzini VT;Anderson F;Leslie A;Kløverpris HN
• 通讯作者: Kløverpris HN