Lactate controls glomerular endothelial barrier integrity in lupus nephritis
Jiaxin Lei, Xingyu Zhai, Yixin Wang, Ying Li, Lei Li, Mengdi Liu, Jing Guo, Lingyi Li, Zhezhuyun Chen, Qinghua Cao, Zhichun Liu, Ting Liu, Lin Xu, Zhenke Wen
Jiaxin Lei, Xingyu Zhai, Yixin Wang, Ying Li, Lei Li, Mengdi Liu, Jing Guo, Lingyi Li, Zhezhuyun Chen, Qinghua Cao, Zhichun Liu, Ting Liu, Lin Xu, Zhenke Wen
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Research Article Nephrology

Lactate controls glomerular endothelial barrier integrity in lupus nephritis

Abstract

Systemic lupus erythematosus (SLE) is a progressive autoimmune disease that affects multiple organs and tissues, with lupus nephritis (LN) as one of its most severe complications. Although LN progression is associated with compromised permeability of human renal glomerular endothelial cells (HRGECs), the underlying mechanisms are not fully defined. Herein, we demonstrate that aberrant glycolysis drives this glomerular endothelial barrier defect by suppressing the transcription of tight junction (TJ) genes. Mechanistically, circulating self-DNA in SLE plasma acts as a ligand that activates the cGAS/STING pathway in HRGECs, driving aberrant glycolytic adaption. The resulting glycolytic product, lactate, serves as a substrate for protein lactylation, leading to extensive lactylation and subsequent ubiquitination of enhancer of zeste homolog 2 (EZH2). In consequence, EZH2 deficiency results in reduced H3K27me3 levels, thereby suppressing the transcription of TJ genes. In a self-DNA–induced SLE model, inhibition of cGAS/STING signaling or lactate production effectively restored the integrity of TJs of HRGECs and concurrently alleviated key LN symptoms. Together, lactate programs lactylation and ubiquitination of EZH2 to impair the glomerular endothelial barrier in human SLE.

Authors

Jiaxin Lei, Xingyu Zhai, Yixin Wang, Ying Li, Lei Li, Mengdi Liu, Jing Guo, Lingyi Li, Zhezhuyun Chen, Qinghua Cao, Zhichun Liu, Ting Liu, Lin Xu, Zhenke Wen

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Figure 1

SLE plasma impairs the TJ barrier in HRGECs.

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SLE plasma impairs the TJ barrier in HRGECs. (A) The correlation between...
(A) The correlation between the expression of TJ-related genes and SLEDAI scores in patients with SLE. (B) Schematic diagram for experimental design. (C) HRGECs were treated with plasma from HCs or patients with SLE for 24 hours. The fluorescence intensity of 4 kDa and 70 kDa FITC-dextran in the lower chamber was measured using a microplate reader. Mean ± SEM from 6 individuals in each group. (D–F) ECs were cultured with 10% or 20% plasma from HCs and patients with SLE. TJ-associated mRNA and protein levels were assessed by qPCR (D, 10%/20% plasma), Western blot (E, 10%/20% plasma), and immunofluorescence staining (F, 10% plasma). Data are mean ± SEM (n = 4 individuals per group for D–E). Scale bar: 10 μm (F). (G) Urinary 4 kDa FITC-dextran fluorescence intensity normalized to creatinine was measured via microplate reader in healthy and SLE model mice. Values are presented as mean ± SEM; 4 mice per group. (H) Localization of 70 kDa FITC-dextran in the glomeruli of healthy mice and SLE model mice was visualized by immunofluorescence microscopy. Scale bar: 50 μm. (I and J) Expression of TJ-associated proteins in glomerular ECs in vivo from healthy and SLE model mice. Data are presented as mean ± SEM; 4 mice per group. (K–M) Healthy mice were subjected to treatment with AAV2-GEC-shZO-1 or negative control shRNA. (K) Urinary protein levels. (L) Periodic acid–Schiff (PAS) staining of renal tissues. (M) Renal IgG deposition. Data are mean ± SEM (n = 4 mice per group for K). Scale bar: 20 μm. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 with unpaired 2-tailed t test (G and K), 2-way ANOVA plus Tukey’s method (C–E, and J), and Pearson’s correlation statistical analysis (A).