HIF-1a+ CD4 T cells coordinate a tissue resident immune cell network in the lung [scRNA-seq]

Pulmonary infection leads to the development of CD4+ T resident helper (TRH) cells in the lung. TRH cells generated after influenza infection support local humoral responses and exhibit differentiation plasticity following infectious challenge. A subset of TRH cells is enriched for expression of the transcription factor HIF-1a which has unknown function in the lung. Here we find that inducible deletion of HIF-1a in CD4 T cells leads to decreased numbers of CXCR6+ tissue resident T cells with minimal impact on peripheral lymphoid responses. At the same time, HIF-1a deletion impairs the replenishment of tissue resident macrophages and NK cells, as well as influenza specific IgA titers. These seemingly disparate responses converge upon a requirement for IL-21 produced by HIF-1a+ CD4 T cells. A similar HIF-1a dependent network is engaged in a lung adenocarcinoma model, highlighting novel roles for HIF-1a+ CD4 T cells in coordinating protective immunity during infection and cancer. Overall design: Following influenza infection control (Hif1a wt/wt CD4 ert2 ki wt ROSA ki wt) and Hif1a KO mice (Hif1a fl/fl CD4 ert2 ki wt ROSA ki wt) were treated with tamoxifen to delete Hif1a in CD4 T cells. Individual mice were hashtagged, and CD45+ cells were sorted from lungs at d45 p.i. and submitted for library preparation.

肺部感染可诱导肺脏中CD4+组织驻留辅助性T细胞（CD4+ T resident helper, TRH）的生成。流感感染后产生的TRH细胞能够支持局部体液免疫应答，并在感染攻击后展现出分化可塑性。有一类TRH细胞亚群高表达转录因子缺氧诱导因子-1α（HIF-1α），该因子在肺脏中的功能尚未明确。本研究发现，在CD4 T细胞中条件性敲除HIF-1α会导致CXCR6+组织驻留T细胞数量减少，而对外周淋巴免疫应答几乎无影响。与此同时，HIF-1α缺失会损害组织驻留巨噬细胞与自然杀伤（NK）细胞的更新补充，同时降低流感特异性IgA滴度。这些看似互不相关的免疫应答最终都依赖于HIF-1α阳性CD4 T细胞产生的白细胞介素-21（IL-21）。类似的HIF-1α依赖调控网络在肺腺癌模型中同样被激活，这揭示了HIF-1α阳性CD4 T细胞在协调感染与癌症过程中的保护性免疫方面的全新功能。整体实验设计：流感感染后，对照组（Hif1a wt/wt CD4 ert2 ki wt ROSA ki wt）与Hif1a敲除组（Hif1a fl/fl CD4 ert2 ki wt ROSA ki wt）小鼠经他莫昔芬处理，以在CD4 T细胞中敲除Hif1a。对每只小鼠进行独特标签标记，于感染后第45天（d45 p.i.）从肺脏中分选CD45+细胞，随后进行文库构建。