Increased risk of occupational trichloroethylene hypersensitivity syndrome at exposure levels higher than 15 mg/L of urinary trichloroacetic acid, regardless of whether the patients had the HLA-B*13:01 allele

Histone demethylase KDM4A mediating macrophage polarization: A potential mechanism of trichloroethylene induced liver injury

Trichloroethylene (TCE) is a commonly used organic solvent in industry. Our previous studies have found that TCE can cause liver injury accompanied by macrophage polarization, but the specific mechanism is unclear. The epigenetic regulation of macrophage polarization is mainly focused on histone modification. Histone lysine demethylase 4A (KDM4A) is involved in the activation of macrophages. In this study, we used a mouse model we investigated the role of KDM4A in the livers of TCE-drinking mice and found that the expression of KDM4A, M1-type polarization indicators, and related inflammatory factors in the livers of TCE-drinking mice. In the study, BALB/c mice were randomly divided into four groups: 2.5 mg/mL TCE dose group and 5.0 mg/mL TCE dose group, the vehicle control group, and the blank control group. We found that TCE triggered M1 polarization of mouse macrophages, characterized by the expression of CD11c and robust production of inflammatory cytokines. Notably, exposure to TCE resulted in markedly increased expression of KDM4A in macrophages. Functionally, the increased expression of KDM4A significantly impaired the expression of H3K9me3 and H3K9me2 and increased the expression of H3K9me1. In addition, KDM4A potentially represents a novel epigenetic modulator, with its upregulation connected to β-catenin activation, a signal critical for the pro-inflammatory activation of macrophages. Furthermore, KDM4A inhibitor JIB-04 treatment resulted in a decrease in β-catenin expression and prevented TCE-induced M1 polarization and the expression of the pro-inflammatory cytokines TNF-α and IL-1β. These results suggest that the association of KDM4A and Wnt/β-catenin cooperatively establishes the activation and polarization of macrophages and global changes in H3K9me3/me2/me1. Our findings identify KDM4A as an essential regulator of the polarization of macrophages and the expression of inflammatory cytokines, which might serve as a potential target for preventing and treating liver injury caused by TCE.

Increased serum anti-CYP2E1 IgG autoantibody levels may be involved in the pathogenesis of occupational trichloroethylene hypersensitivity syndrome: a case-control study

Occupational exposure to trichloroethylene (TCE) causes a systemic skin disorder with hepatitis known as TCE hypersensitivity syndrome (TCE-HS). Human Leukocyte Antigen (HLA)-B*13:01 is its susceptibility factor; however, the immunological pathogenesis of TCE-HS remains unknown. We herein examined the hypothesis that autoantibodies to CYP2E1 are primarily involved in TCE-HS. A case–control study of 80 TCE-HS patients, 186 TCE-tolerant controls (TCE-TC), and 71 TCE-nonexposed controls (TCE-nonEC) was conducted to measure their serum anti-CYP2E1 antibody (IgG) levels. The effects of TCE exposure indices, such as 8-h time-weighted-average (TWA) airborne concentrations, urinary metabolite concentrations, and TCE usage duration; sex; smoking and drinking habits; and alanine aminotransferase (ALT) levels on the antibody levels were also analyzed in the two control groups. There were significant differences in anti-CYP2E1 antibody levels among the three groups: TCE-TC > TCE-HS patients > TCE-nonEC. Antibody levels were not different between HLA-B*13:01 carriers and noncarriers in TCE-HS patients and TCE-TC. The serum CYP2E1 measurement suggested increased immunocomplex levels only in patients with TCE-HS. Multiple regression analysis for the two control groups showed that the antibody levels were significantly higher by the TCE exposure. Women had higher antibody levels than men; however, smoking, drinking, and ALT levels did not affect the anti-CYP2E1 antibody levels. Anti-CYP2E1 antibodies were elevated at concentrations lower than the TWA concentration of 2.5 ppm for TCE exposure. Since HLA-B*13:01 polymorphism was not involved in the autoantibody levels, the possible mechanism underlying the pathogenesis of TCE-HS is that TCE exposure induces anti-CYP2E1 autoantibody production, and HLA-B*13:01 is involved in the development of TCE-HS.

Serum levels of miR-21-5p and miR-339-5p associate with occupational trichloroethylene hypersensitivity syndrome

Background

Trichloroethylene (TCE) hypersensitivity syndrome (THS) is a dose-independent and potentially life-threatening disease. In this study, we sought to identify THS-related miRNAs and evaluate its potential clinical value.

Methods

Serum samples of five patients and five matched TCE contacts were used for screening differential miRNAs. Another 34 patients and 34 matched TCE contacts were used for verifying significantly differential miRNAs with SYBR™ Green PCR and MGB PCR. The diagnostic model based on these miRNAs was established via the support vector machine (SVM) algorithm. Correlation between differential miRNAs and liver function was analyzed via the Spearman correlation test.

Results

A total of 69 miRNAs was found to be differentially expressed. MiR-21-5p and miR-339-5p were verified to have significant higher expressions in patients. The sensitivity, specificity and accuracy of disease model were 100, 75 and 86%, respectively. The two miRNAs showed significant correlations with liver function.

Conclusion

These findings suggested that miRNAs profiles in serum of THS patients had changed significantly, and miR-21-5p and miR-339-5p were associated with THS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12995-021-00308-0.

Endothelin-1/Endothelin Receptor Type A-Angiopoietins/Tie-2 Pathway in Regulating the Cross Talk Between Glomerular Endothelial Cells and Podocytes in Trichloroethylene-Induced Renal Immune Injury

Introduction

This study aimed to investigate the mechanism in regulating the cross talk between glomerular endothelial cells and podocytes in “occupational medicamentosa-like dermatitis induced by trichloroethylene (OMLDT)” patients.

Methods

Totally 6 OMLDT patients, 18 controls, and 102 BALB/c female mice were involved in this study. Patient’s serum endothelin-1 (ET-1), angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2), blood urea nitrogen (BUN), and podocalyxin (PCX) were detected. All the mice were used to establish the trichloroethylene (TCE) sensitized mouse model. Transmission electron microscope results were used to reflect renal glomerulus injury. Protein levels were detected by Western blot. Ang-1/Ang-2 gene level was reflected by RT-PCR. Cell apoptosis level was detected by using TUNEL assay kit.

Results

We found that in OMLDT patients, ET-1, Ang-2, BUN, and PCX were highly expressed but Ang-1 was inhibited. In TCE sensitized positive mouse, the downregulation of Ang-1, pTie-2 and the upregulation of Ang-2 were mediated by ET-1/ET_AR but not ET-1/ET_BR. The promotor of apoptosis proteins was downregulated and the inhibitor of apoptosis proteins was upregulated by treating with BQ123.

Discussion

ET-1/ET_AR-Angs/Tie-2 pathway mediated the cross talk between glomerular endothelial cells and podocytes. BQ123 can alleviate glomerulus immune injury.