Department of Pathology and Immunology, Washington University School of Medicine in Saint Louis, St. Louis, MO 63110.
Department of Intelligent Network for Infection Control, Tohoku University Graduate School of Medicine, 980-8575 Sendai, Japan.
Proc Natl Acad Sci U S A. 2022 Jun 7;119(23):e2204557119. doi: 10.1073/pnas.2204557119. Epub 2022 Jun 2.
C-type lectin domain family 4, member a4 (Clec4a4) is a C-type lectin inhibitory receptor specific for glycans thought to be exclusively expressed on murine CD8α− conventional dendritic cells. Using newly generated Clec4a4-mCherry knock-in mice, we identify a subset of Clec4a4-expressing eosinophils uniquely localized in the small intestine lamina propria. Clec4a4+ eosinophils evinced an immunomodulatory signature, whereas Clec4a4− eosinophils manifested a proinflammatory profile. Clec4a4+ eosinophils expressed high levels of aryl hydrocarbon receptor (Ahr), which drove the expression of Clec4a4 as well as other immunomodulatory features, such as PD-L1. The abundance of Clec4a4+ eosinophils was dependent on dietary AHR ligands, increased with aging, and declined in inflammatory conditions. Mice lacking AHR in eosinophils expanded innate lymphoid cells of type 2 and cleared Nippostrongylus brasiliensis infection more effectively than did wild-type mice. These results highlight the heterogeneity of eosinophils in response to tissue cues and identify a unique AHR-dependent subset of eosinophils in the small intestine with an immunomodulatory profile.
C 型凝集素结构域家族 4,成员 A4(Clec4a4)是一种 C 型凝集素抑制受体,特异性识别糖基,据认为这些糖基仅表达在小鼠 CD8α−常规树突状细胞上。使用新生成的 Clec4a4-mCherry 敲入小鼠,我们鉴定出一小部分 Clec4a4 表达的嗜酸性粒细胞独特地定位于小肠固有层。Clec4a4+嗜酸性粒细胞表现出免疫调节特征,而 Clec4a4−嗜酸性粒细胞表现出促炎特征。Clec4a4+嗜酸性粒细胞表达高水平的芳香烃受体(Ahr),这驱动了 Clec4a4 的表达以及其他免疫调节特征,如 PD-L1。Clec4a4+嗜酸性粒细胞的丰度依赖于饮食中的 AHR 配体,随着年龄的增长而增加,并在炎症条件下下降。缺乏嗜酸性粒细胞中 Ahr 的小鼠比野生型小鼠更有效地扩增 2 型固有淋巴细胞并清除巴西旋毛虫感染。这些结果突出了组织线索对嗜酸性粒细胞的异质性,并鉴定出小肠中具有免疫调节特征的独特 Ahr 依赖性嗜酸性粒细胞亚群。