Gut Microbiome-Host Metabolome Homeostasis upon Exposure to PFOS and GenX in Male Mice.

Alterations of the normal gut microbiota can cause various human health concerns. Environmental chemicals are one of the drivers of such disturbances. The aim of our study was to examine the effects of exposure to perfluoroalkyl and polyfluoroalkyl substances (PFAS)-specifically, perfluorooctane sulfonate (PFOS) and 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propanoic acid (GenX)-on the microbiome of the small intestine and colon, as well as on liver metabolism. Male CD-1 mice were exposed to PFOS and GenX in different concentrations and compared to controls. GenX and PFOS were found to have different effects on the bacterial community in both the small intestine and colon based on 16S rRNA profiles. High GenX doses predominantly led to increases in the abundance of Clostridium sensu stricto, Alistipes, and Ruminococcus, while PFOS generally altered Lactobacillus, Limosilactobacillus, Parabacteroides, Staphylococcus, and Ligilactobacillus. These treatments were associated with alterations in several important microbial metabolic pathways in both the small intestine and colon. Untargeted LC-MS/MS metabolomic analysis of the liver, small intestine, and colon yielded a set of compounds significantly altered by PFOS and GenX. In the liver, these metabolites were associated with the important host metabolic pathways implicated in the synthesis of lipids, steroidogenesis, and in the metabolism of amino acids, nitrogen, and bile acids. Collectively, our results suggest that PFOS and GenX exposure can cause major perturbations in the gastrointestinal tract, aggravating microbiome toxicity, hepatotoxicity, and metabolic disorders.

Nephrotoxicity of perfluorooctane sulfonate (PFOS)-effect on transcription and epigenetic factors.

Perfluorooctane sulfonate (PFOS) is a widespread persistent environmental pollutant implicated in nephrotoxicity with altered metabolism, carcinogenesis, and fibrosis potential. We studied the underlying epigenetic mechanism involving transcription factors of PFOS-induced kidney injury. A 14-day orally dosed mouse model was chosen to study acute influences in vivo. Messenger RNA expression analysis and gene set enrichment analysis were performed to elucidate the relationship between epigenetic regulators, transcription factors, kidney disease, and metabolism homeostasis. PFOS was found to accumulate in mouse kidney in a dose-dependent manner. Kidney injury markers Acta2 and Bcl2l1 increased in expression significantly. Transcription factors, including Nef2l2, Hes1, Ppara, and Ppard, were upregulated, while Smarca2 and Pparg were downregulated. Furthermore, global DNA methylation levels decreased and the gene expression of histone demethylases Kdm1a and Kdm4c were upregulated. Our work implicates PFOS-induced gene expression alterations in epigenetics, transcription factors, and kidney biomarkers with potential implications for kidney fibrosis and kidney carcinogenesis. Future experiments can focus on epigenetic mechanisms to establish a panel of PFOS-induced biomarkers for nephrotoxicity evaluation.

Effect of Perfluorooctanoic Acid on the Epigenetic and Tight Junction Genes of the Mouse Intestine.

Perfluorooctanoic acid (PFOA) has been implicated in various toxicities including neurotoxicity, genotoxicity, nephrotoxicity, epigenetic toxicity, immunotoxicity, reproductive toxicity, and hepatotoxicity. However, information on the accumulation of PFOA in the intestine and its toxic effects on intestinal epigenetics and tight junction (TJ) genes is sparse. CD1 mice were dosed with PFOA (1, 5, 10, or 20 mg/kg/day) for 10 days, and its accumulation and induced alterations in the expression of epigenetic and tight junction genes in the small intestine and colon were evaluated using LC-MS and qPCR techniques. PFOA reduced the expression levels of DNA methyltransferases (Dnmt1, Dnmt3a, Dnmt3b) primarily in the small intestine whereas, in the colon, a decrease was observed only at high concentrations. Moreover, ten-eleven translocation genes (Tet2 and Tet3) expression was dysregulated in the small intestine, whereas in the colon Tets remained unaffected. The tight junction genes Claudins (Cldn), Occludin (Ocln), and Tight Junction Protein (Tjp) were also heavily altered in the small intestine. TJs responded differently across the gut, in proportion to PFOA dosing. Our study reveals that PFOA triggers DNA methylation changes and alters the expression of genes essential for maintaining the physical barrier of intestine, with more profound effects in the small intestine compared to the colon.

Acute PFOA exposure promotes epigenomic alterations in mouse kidney tissues.

Perfluorooctanoic acid (PFOA), a manufactured perfluorochemical is a common surfactant and environmental pollutant found in various consumer products and water sources. Epidemiological studies have demonstrated its association with kidney dysfunction. However, the mechanisms that trigger kidney dysfunction following PFOA exposure is a gap in the field. The work presented explores the potential epigenetic indicators of kidney disease due to exposure to PFOA. In this study, 30 days old CD-1 mice were exposed to 1, 5, 10, or 20 mg/kg/day of PFOA for 10 days. Following acute oral exposure, epigenetic alterations and expression levels of various markers of fibroblast activation were evaluated in kidney tissues. We noted that PFOA-exposed mice exhibited differential methylation yielding 879 differentially methylated regions compared to vehicle. The mRNA expression revealed significant increase in Dnmt1 with decreased Rasal1 expression at higher levels of PFOA exposure suggestive of Rasal1 hypermethylation (an early indicator of fibroblast activation in kidney). Like Dnmt1, we also observed significant increase in Hdac1, 3 and 4. These are class I & II HDACs which are known to be critically altered in some renal diseases. Further, the mRNA expression levels of TGF-ß and α-SMA significantly increased compared to vehicle. The KEGG and Go enrichment pathway analysis of reduced representation bisulfite data also revealed pathways implicated in renal fibrosis. Our study shows clear evidence of epigenetic alterations (DNA methylation and HDAC expression changes) in tissues from mouse kidney following PFOA exposure. Our results also suggest that epigenetic alterations in kidney promote the expression of early markers of fibroblast activation.

In vitro and in vivo anti-Helicobacter pylori activity of selected medicinal plants employed for the management of gastrointestinal disorders.

Five medicinal plants Mentha piperita L., Trachyspermum ammi L., Viola odorata Linn., Matricaria chamomilla L. and Foeniculum vulgare Mill. were selected for their in vitro and in vivo evaluation of anti-Helicobacter pylori activity. In vitro evaluation was performed by using disk diffusion method and minimum inhibitory concentrations were noted while rat models were selected for in vivo activity against four Helicobacter pylori strains isolated form gastric mucosa. Mentha piperita showed largest zone of inhibition with 9 mm diameter among all other extracts. All the plants showed promising anti-Helicobacter pylori activity against four isolates and a reference strain at concentrations of 125, 250, 500 and 1000 µg/ml in comparison with Amoxicillin 1 µg/ml but least MIC was exhibited by Mentha piperita followed by in vivo testing where it competed Amoxicillin at 1000 mg/kg by achieving 80% eradication of Helicobacter pylori in mucosa of infected rats justified by histological examination of stomach. It was concluded that medicinal plants possess strong anti-Helicobacter pylori activity and can be considered a potential source of safe and effective alternative regimens for the eradication of Helicobacter pylori.

Awareness and Attitudes of Research Students Toward Dual-use Research of Concern in Pakistan: A Cross-sectional Questionnaire.

Dual-use research poses a significant challenge for scientists in the biomedical field and for global health security in general. As the scientific knowledge and materials required for the development of biological agents become progressively more accessible and inexpensive, there is an increased need to understand and improve the governance of scientific research. Prevention of the misuse of facilities, equipment, agents, and scientific knowledge requires high levels of awareness of the concept of dual-use research, starting with early-career scientists and graduate students. In this study, the attitudes and level of awareness of postgraduate students in Pakistan toward the issues surrounding dual-use research were assessed through a survey containing both quantitative and qualitative questions in 32 universities in 4 provinces, federal area, and Azad Jammu and Kashmir regions of Pakistan; 933 students responded. Most (58.2%) had never heard of dual-use research of concern (DURC), while 18.5% had heard the term but were unsure of its meaning. Irrespective of prior knowledge, a higher percentage of students (68.6%) felt an obligation to report research misuse. Considering the need for DURC training, 94.1% of the respondents agreed that the principal investigator should take the responsibility to train students on DURC at the start of a research project. When experimental results having dual-use potential, 69.1% indicated they would publish with limited protocol, with 43.5% indicating they would publish the limited protocol only if there was a way for scientists to access their data. The survey results revealed limited DURC awareness among researchers across Pakistan. However, the respondents, although not formally educated about DURC, were quite aware of its impact. The information gained in this survey will be valuable in addressing country-specific awareness and training needs.