HMGB1-mediated formation of IL-33–abundant NETs drives lung-to-kidney injury in severe pneumonia–associated acute kidney injury
Mengqing Ma, Hao Zhang, Weijuan Deng, Xia Du, Mengxing Chen, Dawei Chen, Binbin Pan, Zhaowei Wang, Ting Chen, Caimei Chen, Xin Wan, Changchun Cao
Mengqing Ma, Hao Zhang, Weijuan Deng, Xia Du, Mengxing Chen, Dawei Chen, Binbin Pan, Zhaowei Wang, Ting Chen, Caimei Chen, Xin Wan, Changchun Cao
View: Text | PDF
Research Article Inflammation Nephrology Pulmonology

HMGB1-mediated formation of IL-33–abundant NETs drives lung-to-kidney injury in severe pneumonia–associated acute kidney injury

Abstract

Acute kidney injury (AKI) is a common and fatal complication of severe pneumonia, yet the mechanisms linking pulmonary inflammation to remote kidney injury remain poorly understood. Multicenter cohort data (n = 300) revealed that the incidence of severe pneumonia–associated AKI (SP-AKI) was 53.6%, with a mortality rate of 24.2%. SP-AKI was associated with elevated circulating levels of HMGB1, NETs, and IL-33. Murine experiments demonstrated that alveolar HMGB1 triggers the formation of IL-33–enriched NETs, which migrate to the kidney and activate tubular ST2/NF-κB signaling, driving inflammation and apoptosis. Genetic knockout of IL-33, ST2, or the NET-forming key enzyme PAD4, as well as pharmacological inhibition of HMGB1, IL-33, or NETs, all attenuated lung and kidney injury. Exogenous HMGB1 amplified NET-mediated IL-33 release, establishing a self-sustaining HMGB1/NET/IL-33 feed-forward loop. PAD4 deficiency completely blocked NET generation and disrupted HMGB1/IL-33 signaling. This study identified and validated a damage-associated molecular pattern–driven (DAMP-driven) HMGB1/NET/IL-33 signaling axis that mediates remote kidney injury in SP-AKI, redefining NETs from local effectors to cross-organ pathogenic carriers, thereby providing potential DAMP-targeted therapeutic avenues for SP-AKI.

Authors

Mengqing Ma, Hao Zhang, Weijuan Deng, Xia Du, Mengxing Chen, Dawei Chen, Binbin Pan, Zhaowei Wang, Ting Chen, Caimei Chen, Xin Wan, Changchun Cao

×

Figure 8

HMGB1 induces IL-33 release and aggravates SP-AKI through PAD4-dependent NET formation.

Options: View larger image (or click on image) Download as PowerPoint
HMGB1 induces IL-33 release and aggravates SP-AKI through PAD4-dependent...
(A) Uniform manifold approximation and projection (UMAP) visualization of public scRNA-seq data (GSE274823) derived from BALF in a murine model of acute lung injury (ALI) induced by intratracheal Pseudomonas aeruginosa (PA) infection. Comparative analysis between WT and PAD4/PAD2 double-knockout (DKO) mice reveals distinct cellular subpopulations. Each point represents a single cell, and clusters were identified based on gene expression profiles. Cell types are color-coded as indicated in the legend. (B) Stacked bar plot depicting the relative abundance of major cell types in BALF across each group. (C) Gene set enrichment analysis of the NET formation pathway (predominantly enriched in immature neutrophils) in BALF. (D) The expression levels of the IL-33 gene among various cell types across different groups. (E) Experimental design illustrating WT and PAD4-knockout (PAD4 KO) mice subjected to SP-AKI and treated with recombinant HMGB1 (rHMGB1, 50 μg/kg) or anti-HMGB1 antibody (glycyrrhizin, 50 mg/kg). (F) Serum creatinine (Scr) levels in WT and PAD4 KO mice with SP-AKI following rHMGB1 administration or HMGB1 neutralization. (G and H) Flow cytometry and quantitative analysis of IL-33+ in neutrophils of blood across each group. (I–M) Relative mRNA expression levels of HMGB1 (I), IL-33 (J), inflammatory cytokines IL-6 (K) and IL-1β (L), and NF-κB1 (M) in lung tissues from the indicated groups. (N–R) Relative mRNA expression levels of IL-33 (N), ST2 (O), inflammatory cytokines IL-6 (P) and IL-1β (Q), and NF-κB1 (R), in kidney tissues from the indicated groups. Data are presented as mean ± SD. n = 5 per group. P values were calculated by 1-way ANOVA with post hoc Holm-Šídák test. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. NS, no statistically significant difference.