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Chlorinated polyfluorinated ether sulfonate (F-53B), a chromium-fog depressant widely utilized as an alternative to perfluorooctanesulfonate, can transfer from mother to fetus. Recent research has demonstrated that prenatal exposure to F-53B results in synaptic damage in weaning mice. However, the mechanism underpinning F-53B-triggered synaptic damage during fetal development remains unclear. This study aims to investigate the role of the protein kinase A (PKA)/cAMP response element-binding protein (CREB) pathway, a crucial signaling mechanism known as "synaptic switch", in the early neurotoxicity of F-53B exposure both in vivo and in vitro . Here, C57BL/6 fetal mice were subjected to exposure to F-53B (0, 4, and 40 μg/L) from gestation days (GD) 0 to 14 to evaluate nerve injury prior to delivery. HT22 neurons exposed to F-53B (0, 0.016, 0.08, 0.4, 2, and 10 μmol/L) for 24 h were utilized to elucidate the underlying mechanism. Our results demonstrated that F-53B significantly increased the fluorescence intensity of Nestin (a neural stem cell marker) in the fetal brain hippocampus (GD14). Subsequently, we found that F-53B downregulated the expression of synaptic plasticity markers (SYP, GAP43, and BDNF) in the fetal brain and HT22 neurons. Further molecular docking analysis revealed that F-53B fits into the ligand-binding pockets of PKA and CREB1. Results showed that F-53B inhibited the translocation of PKA protein from the cytoplasm to the neuronal nuclei and reduced the levels of PKA, CREB1, p-PKA(α/β/γ)-Thr197, and p-CREB1-S133 in the nucleus. Furthermore, the expression of synaptic plasticity markers altered by F-53B could be reversed by a PKA agonist and was intensified by a PKA antagonist. In summary, our findings suggest that intrauterine exposure to F-53B can weaken the expression of synaptic plasticity markers in the fetal brain, with this neurotoxicity being mediated by the cytoplasmic retention of PKA., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Co-published by Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, and American Chemical Society.)

Glucocorticoid plays a key role in the growth and organ maturation of fetus. However, the effect of glucocorticoid on the association between per- and polyfluoroalkyl substance (PFAS) exposure and fetal growth is still unknown. We detected cord cortisol (active glucocorticoid in human) and 34 PFAS concentrations in the maternal serum samples, which were collected from 202 mother-fetus pairs in the Maoming Birth Cohort from 2015 to 2018. The mediation effect of cord cortisol on the association between maternal PFAS and the neonatal growth index (NGI) was estimated. We found that higher PFAS concentrations were associated with lower NGI in terms of ponderal index, birth weight (BW), head circumference (HC), and its z-scores (BWZ and HCZ) ( P < 0.05). Fetal cortisol could mediate 12.6-27.3% of the associations between PFAS and NGI. Specifically, cord cortisol mediated the association between branched perfluorooctane sulfonate (branched PFOS) and HCZ by 20.4% and between perfluorooctanoate (PFOA) and HCZ by 27.3%. Our findings provide the first epidemiological data evincing that fetal cortisol could mediate the association between prenatal PFAS exposure and fetal growth. Further investigations are recommended to elucidate the interactions among cord cortisol, PFAS, and fetal growth.

The neurotoxic effects of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) on offspring animals are well-documented. However, epidemiological evidence for legacy PFAS is inconclusive, and for alternative PFAS, it is little known. In this investigation, we selected 718 mother-child pairs from the Chinese Maoming Birth Cohort Study and measured 17 legacy and alternative PFAS in the third-trimester serum. Neuropsychological developments (communication, gross motor function, fine motor function, problem solving ability, and personal-social skills) were assessed at 3, 6, 12, 18, 24, and 36 months using the Ages and Stages Questionnaires 3rd edition. Trajectories of each subscale were classified into persistently low and persistently high groups via group-based trajectory modeling. Logistic regression and grouped weighted quantile sum were fitted to assess the potential effects of individual PFAS and their mixtures, respectively. Higher linear PFHxS levels were associated with elevated odds for the persistently low trajectories of communication (OR = 1.73; 95% CI: 1.12, 2.66) and problem solving ability (OR = 2.11; 95% CI: 1.14, 3.90). Similar findings were observed for linear PFOS, 1m-PFOS, PFDA, PFDoDA, PFUnDA, and legacy PFAS mixture. However, no association was observed for alternative PFAS and their mixture. We provided insights into the longitudinal links between prenatal legacy/alternative PFAS exposure and neuropsychological development trajectories over the first 3 years of life.

Chlorinated polyfluorinated ether sulfonates (Cl-PFESAs) are one kind of replacement chemistry for perfluorooctanesulfonate (PFOS). Recent studies have shown that Cl-PFESAs could interfere with thyroid function in animal models. However, epidemiological evidence on the link between Cl-PFESAs and thyroid function remains scarce. In this study, we focused on two representative legacy perfluoroalkyl substances (PFAS), including PFOS and perfluorooctanoic acid (PFOA), and two PFOS alternatives (6:2 and 8:2 Cl-PFESAs) in the general adult population from a cross-sectional study, the "Isomers of C8 Health Project in China". Three serum thyroid hormones (THs), thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4), were measured. We fitted generalized linear regression, restricted cubic spline regression, and Bayesian kernel machine regression models to assess associations of individual Cl-PFESAs, legacy PFAS, and PFAS mixtures with THs, respectively. We found individual PFAS and their mixtures were nonlinearly associated with THs. The estimated changes of the TSH level (μIU/mL) at the 95th percentile of 6:2 Cl-PFESA and PFOS against the 5th percentile were -0.74 (95% CI: -0.94, -0.54) and -1.18 (95% CI: -1.37, -0.98), respectively. The present study provided epidemiological evidence for the association of 6:2 Cl-PFESA with thyroid hormone levels in the general adult population.

Evidence of the effects of various particle sizes and constituents on blood biomarkers is limited. We performed a panel study with five repeated measurements in 88 healthy college students in Guangzhou, China between December 2017 and January 2018. Mass concentrations of particles with aerodynamic diameters ≤ 2.5 μm (PM 2.5 ), PM 1 , and PM 0.5 and number concentrations of particles with aerodynamic diameters ≤ 200 nm (PN 0.2 ) and PN 0.1 were measured. We used linear mixed-effect models to explore the associations of size-fractionated particulate matter and PM 2.5 constituents with five blood biomarkers 0-5 days prior to blood collection. We found that an interquartile range (45.9 μg/m 3 ) increase in PM 2.5 concentration was significantly associated with increments of 16.6, 3.4, 12.3, and 8.8% in C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and endothelin-1(ET-1) at a 5-day lag, respectively. Similar estimates were observed for PM 1 , PM 0.5 , PN 0.2 , and PN 0.1 . For PM 2.5 constituents, consistent positive associations were observed between F - and sVCAM-1 and CRP and between NH 4 + and MCP-1, and negative associations were found between Na + and MCP-1 and ET-1, between Cl - and MCP-1, and between Mg 2+ and sVCAM-1. Our results suggested that both particle size and constituent exposure are significantly associated with circulating biomarkers among healthy Chinese adults. Particularly, PN 0.1 at a 5-day lag and F - and NH 4 + are the most associated with these blood biomarkers.

Existing evidence is scarce concerning the various effects of different PM sizes and chemical constituents on blood lipids. A panel study that involved 88 healthy college students with five repeated measurements (440 blood samples in total) was performed. We measured mass concentrations of particulate matter with diameters ≤ 2.5 μm (PM 2.5 ), ≤1.0 μm (PM 1.0 ), and ≤0.5 μm (PM 0.5 ) as well as number concentrations of particulate matter with diameters ≤ 0.2 μm (PN 0.2 ) and ≤0.1 μm (PN 0.1 ). We applied linear mixed-effect models to assess the associations between short-term exposure to different PM size fractions and PM 2.5 constituents and seven lipid metrics. We found significant associations of greater concentrations of PM in different size fractions within 5 days before blood collection with lower high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A (ApoA1) levels, higher apolipoprotein B (ApoB) levels, and lower ApoA1/ApoB ratios. Among the PM 2.5 constituents, we observed that higher concentrations of tin and lead were significantly associated with decreased HDL-C levels, and higher concentrations of nickel were associated with higher HDL-C levels. Our results suggest that short-term exposure to PM in different sizes was deleteriously associated with blood lipids. Some constituents, especially metals, might be the major contributors to the detrimental effects.

YM-216391, an antitumor natural product, represents a new class of cyclic peptides containing a polyoxazole-thiazole moiety. Herein we describe its gene cluster encoding the biosynthetic paradigm featuring a ribosomally synthesizing precursor peptide followed by a series of novel posttranslational modifications, which include (i) cleavage of both N-terminal leader peptide and C-terminal extension peptide and cyclization in a head-to-tail fashion, (ii) conversion of an L-Ile to D-allo-Ile, and (iii) β-hydroxylation of Phe by a P450 monooxygenase followed by further heterocyclization and oxidation to form a phenyloxazole moiety. The cluster was heterologously expressed in Streptomyces lividans to bypass difficult genetic manipulation. Deletion of the ymR3 gene, encoding a putative transcriptional regulator, increased the YM-216391 yield about 20-fold higher than the original yields for the heterologous expression of wild-type cluster, which set the stage for further combinatorial biosynthesis.