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The contribution of human gastrointestinal (GI) microbiota and metabolites to host health has recently become much clearer. However, many confounding factors can influence the accuracy of gut microbiome and metabolome studies, resulting in inconsistencies in published results. In this study, we systematically investigated the effects of fecal sampling regions and storage and retrieval conditions on gut microbiome and metabolite profiles from three healthy children. Our analysis indicated that compared to homogenized and snap-frozen samples (standard control [SC]), different sampling regions did not affect microbial community alpha diversity, while a total of 22 of 176 identified metabolites varied significantly across different sampling regions. In contrast, storage conditions significantly influenced the microbiome and metabolome. Short-term room temperature storage had a minimal effect on the microbiome and metabolome profiles. Sample storage in RNALater showed a significant level of variation in both microbiome and metabolome profiles, independent of the storage or retrieval conditions. The effect of RNALater on the metabolome was stronger than the effect on the microbiome, and individual variability between study participants outweighed the effect of RNALater on the microbiome. We conclude that homogenizing stool samples was critical for metabolomic analysis but not necessary for microbiome analysis. Short-term room temperature storage had a minimal effect on the microbiome and metabolome profiles and is recommended for short-term fecal sample storage. In addition, our study indicates that the use of RNALater as a storage medium of stool samples for microbial and metabolomic analyses is not recommended.IMPORTANCE The gastrointestinal microbiome and metabolome can provide a new angle to understand the development of health and disease. Stool samples are most frequently used for large-scale cohort studies. Standardized procedures for stool sample handling and storage can be a determining factor for performing microbiome or metabolome studies. In this study, we focused on the effects of stool sampling regions and stool sample storage conditions on variations in the gut microbiome composition and metabolome profile.

Background: Multiple methods have been used to treat hypertrophic scarring; however, an optimal treatment method remains to be established. We aimed to research and compare the effects of cell-free fat extract (CEFFE) and platelet-rich fibrin (PRF) on hypertrophic scar formation based on histomorphological analysis in this study. Methods: Twelve rabbits were divided into four groups randomly. (CEFFE+PRF group, n=3; CEFFE group, n=3, PRF group, n=3 and Control group, n=3). After the ear hypertrophic scar model were established, the two ears of each rabbit in the four groups were injected with CEFFE 0.05 mL/cm2 + PRF 0.05 mL/cm2, CEFFE 0.1 mL/cm2, PRF 0.1 mL/cm2, and saline 0.1 mL/cm2, respectively. The scar elevation index and histological analysis using hematoxylin-eosin and Masson staining were evaluated after injection on day 40. Results: The CEFFE+PRF group was significantly more effective in the prevention of pathological scar formation than the CEFFE-only, PRF-only, and control groups in terms of capillary count, collagen organization, fibroblast count, and scar elevation index (p< 0.05). Discussion: CEFFE combined with PRF was the most effective treatment for the prevention of hypertrophic scar formation in our study. [ABSTRACT FROM AUTHOR]

[This corrects the article DOI: 10.1371/journal.pone.0074968.].

This document is an editorial introducing a special issue titled "State-of-the-Art Environmental Chemical Exposomics and Metabolomics." The issue contains 13 articles that focus on the relationship between environmental exposures and human health from a comprehensive perspective. The articles explore various topics, including the detection of mycotoxins in food and human plasma, the effects of nanomaterials and micro/nanoplastics on lung cells and embryonic development, the impact of cigarette smoke on gastric cancer cells, the metabolomic characteristics of papillary thyroid cancer, and the toxicity mechanisms of certain chemicals. The articles provide new insights into environmental chemical exposomes and metabolomics in toxicology, contributing to our understanding of these fields and informing future research and policy-making. [Extracted from the article]

Scientific Reports 5: Article number: 15512; published online: 22 October 2015; updated: 13 April 2016 The Acknowledgements section in this Article is incomplete. “This study was supported by National 973 Program (2012CBA01305); National Science Fund for Outstanding Young Scholars (81322039); National Natural Science Foundation (31371524); Distinguished Young Scholars of Jiangsu Province (BK20130041); Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD); New Century Excellent Talents in University (NCET-13-0870) and the California Tobacco-Related Disease Research Program (TRDRP) Grant 19XT-0070 (to B.

Thirdhand smoke (THS) is a new term for the toxins in cigarette smoke that linger in the environment long after the cigarettes are extinguished. The effects of THS exposure on male reproduction have not yet been studied. In this study, metabolic changes in male germ cell lines (GC-2 and TM-4) were analyzed after THS treatment for 24 h. THS-loaded chromatography paper samples were generated in a laboratory chamber system and extracted in DMEM. At a paper: DMEM ratio of 50 μg/ml, cell viability in both cell lines was normal, as measured by the MTT assay and markers of cytotoxicity, cell cycle, apoptosis and ROS production were normal as measured by quantitative immunofluorescence. Metabolomic analysis was performed on methanol extracts of GC-2 and TM-4 cells. Glutathione metabolism in GC-2 cells, and nucleic acid and ammonia metabolism in TM-4 cells, was changed significantly by THS treatment. RT-PCR analyses of mRNA for enzyme genes Gss and Ggt in GC-2 cells, and TK, SMS and Glna in TM-4 cells reinforced these findings, showing changes in the levels of enzymes involved in the relevant pathways. In conclusion, exposure to THS at very low concentrations caused distinct metabolic changes in two different types of male reproductive cell lines.

Silica nanoparticles (NP) is one of the most commonly used nanomaterials with potential health hazards. However, the effects of Silica NP on germ cells and the underlying mechanisms are still unclear. In this study, GC-2 and TM-4, which are two different types of male germ cells were exposed to Silica NP for 24h, and then general cytotoxicity and multi-parameter cytotoxicity were evaluated. Our results showed that Silica NP could induce apoptosis in GC-2 cells. Transmission electron microscopy (TEM) results showed that Silica NP was localized in the lysosomes of GC-2 cells. High content screening (HCS) showed that Silica NP exposure could increased cell permeabilization and decreased mitochondrial membrane potential in GC-2 cells. The mRNA and protein levels of apoptosis markers (Bax, Caspase-3, Caspase-9) in GC-2 cells were significantly increased, while Bcl-2 was decreased. Accordingly, the expression level of miR-98, which can regulate Caspase-3, was significantly decreased. Huwe1, the host gene of miR-98, was positively associated with miR-98 expression after Silica NP exposure. Dual luciferase reporter assay suggested that miR-98 directly targets Caspase-3. These results suggest that Silica NP induces apoptosis via loss of mitochondrial membrane potential and Caspase-3 activation, while miR-98 plays key role in modulating this effect.

Triclosan (TCS) poses potential risks to reproduction and development due to its endocrine-disrupting properties. However, the mechanism of TCS's effects on early embryonic development is little known. Embryonic stem cells (ESC) and zebrafish embryos provide valuable models for testing the toxic effects of environmental chemicals on early embryogenesis. In this study, mouse embryonic stem cells (mESC) were acutely exposed to TCS for 24 h, and general cytotoxicity and the effect of TCS on pluripotency were then evaluated. In addition, zebrafish embryos were exposed to TCS from 2- to 24-h post-fertilization (hpf), and their morphology was evaluated. In mESC, alkaline phosphatase staining was significantly decreased after treatment with the highest concentration of TCS (50 μM). Although the expression levels of Sox2 mRNA were not changed, the mRNA levels of Oct4 and Nanog in TCS-treated groups were significantly decreased compared to controls. In addition, the protein levels of Oct4, Sox2 and Nanog were significantly reduced in response to TCS treatment. MicroRNA (miR)-134, an expression inhibitor of pluripotency markers, was significantly increased in TCS-treated mESC. In zebrafish experiments, after 24 hpf of treatment, the controls had developed to the late stage of somitogenesis, while embryos exposed to 300 μg/L of TCS were still at the early stage of somitogenesis, and three genes (Oct4, Sox2 and Nanog) were upregulated in treated groups when compared with the controls. The two models demonstrated that TCS may affect early embryonic development by disturbing the expression of the pluripotency markers (Oct4, Sox2 and Nanog).

Bisphenol A (BPA) poses potential risks to reproduction and development. However, the mechanism of BPA's effects on early embryonic development is still unknown. Embryonic stem cells (ESC) and embryoid bodies (EB) provide valuable in vitro models for testing the toxic effects of environmental chemicals in early embryogenesis. In this study, mouse embryonic stem cells (mESC) were acutely exposed to BPA for 24h, and general cytotoxicity and the effect of BPA on pluripotency were then evaluated. Meanwhile, mouse embryoid bodies (mEB) were exposed to BPA up to 6 days and their differentiation capacity was evaluated. In mESC and mEB, we found that BPA up-regulated pluripotency markers (Oct4, Sox2 and Nanog) at mRNA and/or protein levels. Moreover, BPA increased the mRNA levels of endodermal markers (Gata4,Sox17) and mesodermal markers (Sma,Desmin), and reduced the mRNA levels of ectodermal markers (Nestin,Fgf5) in mEB. Furthermore, microRNA(miR)-134, an expression inhibitor of pluripotency markers including Oct4, Sox2 and Nanog, was decreased both in BPA-treated mESC and mEB. These results firstly indicate that BPA may disturb pluripotency in mESC and differentiation of mEB, and may inhibit ectodermal lineage differentiation of mEB while miR-134 may play a key role underlying this effect.

Perfluorooctane sulfonate (PFOS) poses potential risks to reproduction and development. Mouse embryonic stem cells (mESCs) are ideal models for developmental toxicity testing of environmental contaminants in vitro. However, the mechanism by which PFOS affects early embryonic development is still unclear. In this study, mESCs were exposed to PFOS for 24 h, and then general cytotoxicity and pluripotency were evaluated. MTT assay showed that neither PFOS (0.2 µM, 2 µM, 20 µM, and 200 µM) nor control medium (0.1% DMSO) treatments affected cell viability. Furthermore, there were no significant differences in cell cycle and apoptosis between the PFOS treatment and control groups. However, we found that the mRNA and protein levels of pluripotency markers (Sox2, Nanog) in mESCs were significantly decreased following exposure to PFOS for 24 h, while there were no significant changes in the mRNA and protein levels of Oct4. Accordingly, the expression levels of miR-145 and miR-490-3p, which can regulate Sox2 and Nanog expressions were significantly increased. Chrm2, the host gene of miR-490-3p, was positively associated with miR-490-3p expression after PFOS exposure. Dual luciferase reporter assay suggests that miR-490-3p directly targets Nanog. These results suggest that PFOS can disturb the expression of pluripotency factors in mESCs, while miR-145 and miR-490-3p play key roles in modulating this effect.