Relationship between N,N-dimethylformamide exposure, PNPLA3, GCKR, COL13A1 and TM6SF2 genes, and liver injury

The potential health risks of N,N-dimethylformamide: An updated review

N,N-dimethylformamide (DMF) is a universally used industrial material with exponential growth in production and consumption worldwide. The frequently reported occupational DMF poisoning cases in some countries and the gradually recognized unavoidable health risks to the general population highlight that DMF should still be a matter of concern. Previous studies have demonstrated that the liver is the primary target organ of DMF exposure and multiple mechanisms have been revealed. However, most of these studies investigate the detrimental effects of acute and subacute DMF exposure, while the effects of chronic DMF exposure are rarely studied. Furthermore, the key mechanism for the acute hepatotoxicity of DMF remains to be elucidated. Future research may focus on the identification of efficient preventive measures against the toxicity of DMF to occupational workers, the investigation of the detrimental effects of DMF at environmentally relevant doses, and the studies on the elimination and recycling of DMF in industrial wastes. Herein, we present an updated review of the metabolism of DMF, the biomarker of DMF exposure, underlying molecular mechanisms of DMF-induced hepatotoxicity, and the toxicity of DMF to both occupational workers and general populations and discuss the possible directions in future studies.

N, N-dimethylformamide exposure induced liver abnormal mitophagy by targeting miR-92a-1-5p-BNIP3L pathway in vivo and vitro

N, N-dimethylformamide (DMF) is a widely existing harmful environmental pollutant from industrial emission which can threat human health for both occupational and general populations. Epidemiological and experimental studies have indicated liver as the primary target organ of DMF. However, the molecular mechanism under DMF-induced hepatoxicity remains unclear. In the present study, we identified that DMF could induce abnormal autophagy flux in cells. We also showed that DMF-induced mitochondrial dysfunction and lethal mitophagy which further leads to autophagic cell death. Next, miRNA microarray analysis identified miR-92a-1-5p as the most down-regulated miRNA upon DMF exposure. Mechanistically, miR-92a-1-5p regulated mitochondrial function and mitophagy by targeting mitochondrial protein BNIP3L. Exogenous miR-92a-1-5p significantly attenuated DMF-induced mitochondrial dysfunction and mitophagy in vitro and in vivo. Our study highlights the mechanistic link between miRNAs and mitophagy under environmental stress, which provided a new clue for the mitochondrial epigenetics mechanism on environmental toxicant-induced hepatoxicity.

Exposure of mouse oocytes to N,N-dimethylformamide impairs mitochondrial functions and reduces oocyte quality

N,N-dimethylformamide (DMF) is a widely-used solvent for the synthesis of synthetic fibers such as polyacrylonitrile fiber, and can also be used to make medicine. Although this organic solvent has multipurpose applications, its biological toxicity cannot be ignored and its impact on mammalian reproduction remains largely unexplored. Our study found that DMF exposure inhibited oocyte maturation and fertilization ability. Transcriptomic analysis indicated that DMF exposure changed the expression of genes and transposable elements in oocytes. Subcellular structure examination found that DMF exposure caused mitochondrial dysfunction, abnormal aggregation of mitochondria and decreased mitochondrial membrane potential in mouse oocytes. Its exposure also caused abnormal distribution of Golgi apparatus and endoplasmic reticulum which formed large number of clusters. In addition, oxidative stress occurs in oocytes exposed to DMF, which was manifested by an increase in the level of reactive oxygen species. We found that DMF exposure induced disordered spindle and chromosomes abnormality. Meanwhile, we examined various histone modification levels in oocytes exposed to DMF and found that DMF exposure reduced H3K9me3, H3K9ac, H3K27ac, and H4K16ac levels in mouse oocytes. Moreover, DMF-treated oocytes failed to form pronuclei after fusion with normal sperm. Collectively, DMF exposure caused mitochondrial damage, oxidative stress, spindle assembly and chromosome arrangement disorder, leading to oocyte maturation arrest and fertilization failure.

Integration of proteomics, lipidomics, and metabolomics reveals novel metabolic mechanisms underlying N, N-dimethylformamide induced hepatotoxicity

N, N-Dimethylformamide (DMF) is a universal organic solvent which widely used in various industries, and a considerable amount of DMF is detected in industrial effluents. Accumulating animal and epidemiological studies have identified liver injury as an early toxic effect of DMF exposure; however, the detailed mechanisms remain poorly understood. In this study, we systematically integrated the quantitative proteomics, lipidomics, and metabolomics data obtained from the primary human hepatocytes exposed to DMF, to depict the complicated biochemical reactions correlated to liver damage. Eventually, we identified 284 deregulated proteins (221 downregulated and 63 upregulated) and 149 deregulated lipids or metabolites (99 downregulated and 50 upregulated) induced by DMF exposure. Further, the integration of the protein-metabolite (lipid) interactions revealed that N-glycan biosynthesis (involved in the endoplasmic reticulum stress and the unfolded protein response), bile acid metabolism (involved in the lipid metabolism and the inflammatory process), and mitochondrial dysfunction and glutathione depletion (both contributed to reactive oxygen species) were the typical biochemical reactions disturbed by DMF exposure. In summary, our study identified the versatile protein, lipid, and metabolite molecules in multiple signaling and metabolic pathways involved in DMF induced liver injury, and provided new insights to elucidate the toxic mechanisms of DMF.

The influence of airborne N,N-dimethylformamide on liver toxicity measured in industry workers: A systematic review and meta-analysis

Background:

Modern industry is developing and so is the consumption of N, N-dimethylformamide (DMF) and the occupational population exposed to DMF. However, chronic occupational and experimental exposure to DMF has been especially linked to liver and gastrointestinal disturbances.

Aims:

This study aims to systematically review and evaluate with a meta-analysis the influence of DMF exposure on human liver toxicity.

Methods:

The PubMed/Medline, the ECHA restriction dossier and the Web of Science were searched. Midpoint DMF exposure levels were calculated, and the association between DMF exposure and liver toxicity was investigated. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

Results:

Of 92 screened articles, 19 articles were included in the review and of them, 10 articles were included in the meta-analysis. No association was observed when the midpoint DMF exposure was less than 20 mg/m3 (OR: 1.58, 95% CIs: 0.68–3.65). A positive association between DMF exposure and liver toxicity was observed when the midpoint DMF exposure was between 21 mg/m3 and 25 mg/m3 (OR: 3.26, 95% CIs: 1.38–7.73).

Conclusions:

Higher exposure DMF levels are associated with liver toxicity. However, these results tend to overestimate potential risks because the use of midpoint exposures includes and gives weight to populations at the upper end of the exposure distributions and because liver toxicity was defined as a statistical significant difference in liver enzyme levels compared to control groups, which is not identical to biologically relevant effects and adverse health effects.