Endothelial Cell Expression of a STING Gain-of-function Mutation Initiates Pulmonary Lymphocytic Infiltration

Patients afflicted with STING gain-of-function mutations frequently present with debilitating interstitial lung disease (ILD) that is recapitulated in mice expressing the STINGV154M mutation (VM). Prior radiation chimera studies revealed an unexpected and critical role for non-hematopoietic cells in initiating ILD. To identify STING-expressing non-hematopoietic cell types required for the development of ILD, we generated a conditional knock-in (CKI) model and directed expression of the VM allele to hematopoietic cells, fibroblasts, epithelial cells, or endothelial cells. Only endothelial cell-targeted VM expression resulted in enhanced recruitment of immune cells to the lung associated with chemokine expression and the formation of bronchus-associated lymphoid tissue, as seen in the parental VM strain. These findings reveal the importance of endothelial cells as instigators of STING-driven lung disease and suggest that therapeutic targeting of STING inhibitors to endothelial cells could potentially mitigate inflammation in the lungs of SAVI patients or patients afflicted with other ILD-related disorders. Overall design: To investigate role of the STING gain-of-function mutation V154M (VM), in endothelial cells, we generated a conditioal knock-in (CKI) mouse model of the VM mutation in all cells (CKI x CAGG-cre ERTM) and endothelial cells (CKI x Cdh5-cre ERT2). To understand how ubiquitous and endothelial targeting of VM alters gene expression within lung stromal and parenchymal cells, we depleted hematopoietic (CD45+) and erythrocytes (Ter119+) from the lungs and performed RNA-seq.

携带STING（stimulator of interferon genes）功能获得性突变的患者常罹患致残性间质性肺病（interstitial lung disease，ILD），该疾病表型可在表达STINGV154M突变（简称VM）的小鼠模型中重现。既往辐射嵌合研究揭示了非造血细胞在ILD起始过程中意想不到但至关重要的作用。为鉴定ILD发生所必需的表达STING的非造血细胞亚型，我们构建了条件性敲入（conditional knock-in，CKI）模型，并将VM等位基因定向表达于造血细胞、成纤维细胞、上皮细胞或内皮细胞中。仅在内皮细胞中定向表达VM，即可重现亲本VM小鼠品系中的表型：诱导肺部免疫细胞募集增强，该过程伴随趋化因子表达上调及支气管相关淋巴组织（bronchus-associated lymphoid tissue）的形成。本研究结果证实了内皮细胞作为STING介导性肺病的始动因素的重要性，并提示将STING抑制剂靶向递送于内皮细胞，或可减轻SAVI患者及其他ILD相关疾病患者的肺部炎症。整体实验设计：为探究STING功能获得性突变V154M（VM）在内皮细胞中的作用，我们构建了两类条件性敲入（CKI）小鼠模型：一类为可在全身所有细胞中表达VM突变的模型（CKI x CAGG-cre ERTM），另一类为仅在内皮细胞中表达VM突变的模型（CKI x Cdh5-cre ERT2）。为明确VM的全身定向表达与内皮细胞定向表达如何改变肺基质细胞及实质细胞的基因表达谱，我们从肺部样本中去除了造血细胞（CD45+）与红细胞（Ter119+），并进行了RNA测序（RNA-seq）。