This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

No abstract

Tobacco smoking, a risk factor for several human diseases, can lead to alterations in DNA methylation. Smoking is a key source of cadmium exposure; however, there are limited studies examining DNA methylation alterations following smoking-related cadmium exposure. To identify such cadmium exposure-related DNA methylation, we performed genome-wide DNA methylation profiling using DNA samples from 50 smokers and 50 non-smokers. We found that a total of 136 CpG sites (including 70 unique genes) were significantly differentially methylated in smokers as compared to that in non-smokers. The CpG site cg05575921 in the AHRR gene was hypomethylated (Δ ß > − 0.2) in smokers, which was in accordance with previous studies. The rs951295 (within RNA gene LOC105370802) and cg00587941 sites were under-methylated by > 15% in smokers, whereas cg11314779 (within CELF6) and cg02126896 were over-methylated by ≥ 15%. We analyzed the association between blood cadmium concentration and DNA methylation level for 50 smokers and 50 non-smokers. DNA methylation rates of 307 CpG sites (including 207 unique genes) were significantly correlated to blood cadmium concentration (linear regression P value < 0.001). The four significant loci (cg05575921 and cg23576855 in AHRR, cg03636183 in F2RL3, and cg21566642) were under-methylated by > 10% in smokers compared to that in non-smokers. In conclusion, our study demonstrated that DNA methylation levels of rs951295, cg00587941, cg11314779, and cg02126896 sites may be new putative indicators of smoking status. Furthermore, we showed that these four loci may be differentially methylated by cadmium exposure due to smoking.

No abstract

No abstract

Glyphosate is the most widely used herbicide worldwide. However, since the International Agency for Research on Cancer (IARC) classified glyphosate as a Class 2A 'probable carcinogen' to humans, the safety of this synthetic chemical has been under debate and requires validation. Most studies on glyphosate have been conducted in animals, and the effects of glyphosate in humans are not fully understood. In the present study, we report that glyphosate increases the rate of cell growth in human embryonic kidney 293 (HEK293) cells. Interestingly, the concentrations of glyphosate ranging between 0.6 and 18 µM enhance cell proliferation, while lower or higher concentrations do not stimulate cell growth or interfere with it, respectively. At the molecular level, cell biology and biochemical data demonstrate that glyphosate promotes the transcription of EGR1, JUN, FOS, and MYC, which are critical transcription factors and immediate early genes for cell cycle progression, and cell cycle regulators including cyclin B1, cyclin D1, and p21. NEAT1, a long non-coding RNAs that is implicated in cancers and active gene transcription are increased in glyphosate-treated cells. In addition, the absorption efficiency of glyphosate to HEK293 cells estimates approximately 11 pM/cell/day, and glyphosate metabolism appears increased when incubated with HEK293 cells. Our findings provide valuable evidence on the effects of glyphosate on human cell growth and suggest that glyphosate promotes cell proliferation by activating gene expression of cell cycle regulators in humans in vitro.

No abstract

BackgroundObesity is a chronic low-grade inflammatory disease that is generally characterized by enhanced inflammation in obese adipose tissue (AT). Here, we investigated alterations in gene expression between lean and obese conditions using mRNA-Seq data derived from human purified adipocytes (ACs) and preadipocytes (preACs). ResultsWe defined four classes of differentially expressed genes (DEGs) by comparing gene expression between 1) lean and obese ACs, 2) lean and obese preACs, 3) lean ACs and lean preACs, and 4) obese ACs and obese preACs. Based on an analysis of comparison 1, numerous canonical obesity-related genes, particularly inflammatory genes including IL6, TNF- and IL-1, i.e., the genes that are expected to be upregulated in obesity conditions, were found to be expressed at significantly lower levels in obese ACs than in lean ACs. In contrast, some inflammatory genes were found to be expressed at higher levels in obese preACs than lean preACs in the analysis of comparison 2. These two results indicate that (1) up-/downregulation of genes in ACs and preACs is inversely controlled during the fat deposition process and (2) preACs rather than ACs have increased inflammatory response genes in comparisons of lean and obese conditions for each of these cell types. Analysis of comparisons 3 and 4 showed that inflammatory gene classes were expressed at higher levels in differentiated ACs than undifferentiated preACs under both lean and obese conditions; however, the degree of upregulation was greater for lean than for obese conditions.ConclusionsTaken together, our analyses may suggest that lean fat differentiation involves even greater enhancement of inflammatory responses than does obese fat differentiation.