Loss of PADI2 and PADI4 ameliorates sepsis-induced acute lung injury by suppressing NLRP3+ macrophages
Xin Yu, Yujing Song, Tao Dong, Wenlu Ouyang, Liujiazi Shao, Chao Quan, Kyung Eun Lee, Tao Tan, Allan Tsung, Katsuo Kurabayashi, Hasan B. Alam, Mao Zhang, Jianjie Ma, Yongqing Li
Xin Yu, Yujing Song, Tao Dong, Wenlu Ouyang, Liujiazi Shao, Chao Quan, Kyung Eun Lee, Tao Tan, Allan Tsung, Katsuo Kurabayashi, Hasan B. Alam, Mao Zhang, Jianjie Ma, Yongqing Li
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Research Article Immunology Inflammation

Loss of PADI2 and PADI4 ameliorates sepsis-induced acute lung injury by suppressing NLRP3+ macrophages

Abstract

Sepsis-induced acute lung injury (ALI) is prevalent in patients with sepsis and has a high mortality rate. Peptidyl arginine deiminase 2 (PADI2) and PADI4 play crucial roles in mediating the host’s immune response in sepsis, but their specific functions remain unclear. Our study shows that Padi2–/– Padi4–/– double KO (DKO) improved survival, reduced lung injury, and decreased bacterial load in Pseudomonas aeruginosa (PA) pneumonia–induced sepsis mice. Using single-cell RNA-Seq (scRNA-Seq), we found that the deletion of Padi2 and Padi4 reduced the Nlrp3+ proinflammatory macrophages and fostered Chil3+ myeloid cell differentiation into antiinflammatory macrophages. Additionally, we observed the regulatory role of the NLRP3/Ym1 axis upon DKO, confirmed by Chil3 knockdown and Nlrp3-KO experiments. Thus, eliminating Padi2 and Padi4 enhanced the polarization of Ym1+ M2 macrophages by suppressing NLRP3, aiding in inflammation resolution and lung tissue repair. This study unveils the PADIs/NLRP3/Ym1 pathway as a potential target in treatment of sepsis-induced ALI.

Authors

Xin Yu, Yujing Song, Tao Dong, Wenlu Ouyang, Liujiazi Shao, Chao Quan, Kyung Eun Lee, Tao Tan, Allan Tsung, Katsuo Kurabayashi, Hasan B. Alam, Mao Zhang, Jianjie Ma, Yongqing Li

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Figure 5

Resolution of inflammation prompted by Chil3+ myeloid cells through differentiation into M2 macrophages.

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Resolution of inflammation prompted by Chil3+ myeloid cells through diff...
(A) Violin plots depicting the expression levels of Chil3 and Mrc1 genes across myeloid cell clusters in the WT PA and DKO PA groups (n = 3 mice/group). (B) qPCR analysis of Chil3 and Mrc1 gene expression in BALF cell lysates from WT and DKO mice 24 hours after PA inoculation (n = 5–8 mice/group). (C) Western blot analysis for Ym1 and CD206 proteins in BALF cell lysates from WT and DKO mice 24 hours after PA inoculation (n = 5–6 mice/group). Relative protein expression levels are shown on the right panel. (D) IHC staining for Ym1 in lung tissues of WT and DKO mice within the PA-induced sepsis group. A zoomed-in view reveals Ym1hi myeloid cell from DKO mice (n = 3 mice/group). Scale bars: 50 μm (upper panels); 25 μm (lower panels). (E) ELISA results showing concentrations of M1-related markers (TNF-α, KC, IL-6, and MIP-1β) in the BALF and serum of WT and DKO mice 24 hours after PA inoculation (n = 5 mice/group). (F) ELISA results showing concentrations of M2-related markers (Ym1 and TGF-β) in the BALF and serum of WT and DKO mice 24 hours after PA inoculation (n = 5–7/group). Results in B–F were representative of at least 3 independent experiments. Data for all bar charts were analyzed using unpaired Student’s t tests or 1-way ANOVA. Data are presented as means ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.