The negative feedback loop of NF-κB/miR-376b/NFKBIZ in septic acute kidney injury
Zhiwen Liu, Chengyuan Tang, Liyu He, Danyi Yang, Juan Cai, Jiefu Zhu, Shaoqun Shu, Yuxue Liu, Lijun Yin, Guochun Chen, Yu Liu, Dongshan Zhang, Zheng Dong
Zhiwen Liu, Chengyuan Tang, Liyu He, Danyi Yang, Juan Cai, Jiefu Zhu, Shaoqun Shu, Yuxue Liu, Lijun Yin, Guochun Chen, Yu Liu, Dongshan Zhang, Zheng Dong
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Research Article Nephrology

The negative feedback loop of NF-κB/miR-376b/NFKBIZ in septic acute kidney injury

Abstract

Sepsis is the leading cause of acute kidney injury (AKI). However, the pathogenesis of septic AKI remains largely unclear. Here, we demonstrate a significant decrease of microRNA-376b (miR-376b) in renal tubular cells in mice with septic AKI. Urinary miR-376b in these mice was also dramatically decreased. Patients with sepsis with AKI also had significantly lower urinary miR-376b than patients with sepsis without AKI, supporting its diagnostic value for septic AKI. LPS treatment of renal tubular cells led to the activation of NF-κB, and inhibition of NF-κB prevented a decrease of miR-376b. ChIP assay further verified NF-κB binding to the miR-376b gene promoter upon LPS treatment. Functionally, miR-376b mimics exaggerated tubular cell death, kidney injury, and intrarenal production of inflammatory cytokines, while inhibiting miR-376b afforded protective effects in septic mice. Interestingly, miR-376b suppressed the expression of NF-κB inhibitor ζ (NFKBIZ) in both in vitro and in vivo models of septic AKI. Luciferase microRNA target reporter assay further verified NFKBIZ as a direct target of miR-376b. Collectively, these results illustrate the NF-κB/miR-376b/NFKBIZ negative feedback loop that regulates intrarenal inflammation and tubular damage in septic AKI. Moreover, urinary miR-376b is a potential biomarker for the diagnosis of AKI in patients with sepsis.

Authors

Zhiwen Liu, Chengyuan Tang, Liyu He, Danyi Yang, Juan Cai, Jiefu Zhu, Shaoqun Shu, Yuxue Liu, Lijun Yin, Guochun Chen, Yu Liu, Dongshan Zhang, Zheng Dong

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Figure 9

Evaluation of urinary miR-376b as a biomarker for septic AKI.

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Evaluation of urinary miR-376b as a biomarker for septic AKI. (A and B) ...
(A and B) Male C57BL/6 mice were injected with 10 mg/kg LPS to collect serum and urine samples at indicated time points to measure miR-376b. The values were normalized with that of control mice (LPS time 0) which was arbitrarily set as 1. Serum miR-376b showed a significant decrease at 24 hours after LPS exposure (A), whereas urinary miR-376b showed a significant decrease at 12 and 24 hours (B). All values in A and B are presented as mean ± SD (n = 4, 2-tailed Student’s t test), *P < 0.05 vs. control mice. (C) Serum and urinary miR-376b in healthy subjects (control) and patients with sepsis with or without AKI. The values were normalized with that of serum or urinary miR-376b of healthy subjects (control), which was arbitrarily set as 1. (D) Correlation analysis of urinary miR-376b with serum creatinine in patients with sepsis (r = –0.33 Spearman’s correlation test). (E) Correlation analysis of urinary miR-376b with BUN in patients with sepsis (r = –0.34, Spearman’s correlation test). (F) ROC curves for the detection of septic AKI in patients with sepsis using urinary miR-376b. (G) Urinary [TIMP2]*[IGFBP7] in healthy subjects and patients with sepsis with or without AKI. (H) ROC curves for the detection of AKI in patients with sepsis using urinary [TIMP2]*[IGFBP7]. Values in C and G are presented as mean ± SD (n = 10 or n = 20, 1-way ANOVA with Tukey’s multiple comparisons test), *P < 0.05.