The adverse health effects of bisphenol A and related toxicity mechanisms.

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

Guidelines for the use and interpretatoin of assays for monitoring autophagy

In order to understand the negative effects of bisphenol A (BPA) alternatives comprehensively, zebrafish embryos were used to assess the lethality, developmental effects, and estrogenic activity of bisphenol analogues. The in silico estrogenic activities of bisphenol analogues were assayed by binding simulation. According to our results, the lethality of bisphenol analogues decreased in order of bisphenol AF (BPAF) > BPA > bisphenol F (BPF) > bisphenol S (BPS). BPAF and BPF induced significant effects on zebrafish embryos, including decreased heart rate, hatching inhibition, and teratogenic effects. The binding potentials of bisphenol analogues toward zebrafish ERs (zfERS) decreased in the following order: BPAF > BPA > BPF > BPS. Among the three subtypes of zfERs, zfERβ2 showed the highest binding activity toward the bisphenols, followed by zfERα and zfERβ1. In vivo estrogenic activity tests showed that BPAF, BPA, and BPF significantly enhanced the protein levels of ERα along with the mRNA levels of esr1, esr2a, esr2b, and vtg1 in zebrafish embryos. Esr2b showed the strongest response to BPAF and BPA exposure among the three esrs. In contrast, BPS did not significantly regulate ER protein level or ER transcription. In conclusion, BPAF showed the highest lethality, developmental effects, and estrogenic activity (both in silico and in vivo) followed by BPA and BPF. BPS showed the weakest toxicity and estrogenic activity. zfERβ2 might act as the main target among the three ER subtypes of zebrafish after exposure to BPAF and BPA.

Developmental Effects and Estrogenicity of Bisphenol A Alternatives in a Zebrafish Embryo Model

The hazardous threat of Bisphenol A: Toxicity, detection and remediation.

The hazardous threat of Bisphenol A: Toxicity, detection and remediation

Objective:Hypertensive nephropathy is one of the major causes of chronic kidney disease (CKD). Bisphenol A (BPA) is associated with elevated blood pressure and urinary albuminuria. The aim of this study is to evaluate the association between serum BPA with the progression of CKD in patients with pri

Serum bisphenol A as a predictor of chronic kidney disease progression in primary hypertension: a 6-year prospective study.

The prevalence of hyperuricemia has increased rapidly over the past decades. Bisphenol A (BPA) is an environmental endocrine disruptor. We investigated the effects of BPA on uric acid metabolism and its potential mechanisms. Experiments were performed in different animal models, cell cultures, and humans. In 3 different animal models, BPA exposure increased serum and hepatic uric acid with enhanced activity of xanthine oxidase (XO) in liver, whereas the excretion of uric acid was unchanged. Both in vivo and in vitro, BPA-induced uric acid production was decreased after treatment with allopurinol, which is a XO inhibitor. XO led to the accumulation of uric acid after xanthine was added, with the enzyme-catalyzed reaction, which was enhanced by BPA. Altered secondary structures of XO were found by circular dichroism analysis in the conditions of different BPA concentrations. Molecular docking portrayed Asp360 and Lys422 of XO to be the preferred binding sites for BPA. Mutation of both sites significantly blocked the effect of BPA on XO activity. In humans, patients with hyperuricemia exhibited higher levels of serum BPA than subjects without hyperuricemia. These findings demonstrate BPA promotes hyperuricemia by increasing hepatic uric acid synthesis via the activation of XO, probably through direct binding.-Ma, L., Hu, J., Li, J., Yang, Y., Zhang, L., Zou, L., Gao, R., Peng, C., Wang, Y., Luo, T., Xiang, X., Qing, H., Xiao, X., Wu, C., Wang, Z., He, J. C., Li, Q., Yang, S. Bisphenol A promotes hyperuricemia via activating xanthine oxidase.

https://faseb.onlinelibrary.wiley.com/doi/pdf/10.1096/fj.201700755R

Bisphenol A promotes hyperuricemia via activating xanthine oxidase

Accumulating evidence suggests that bisphenol A (BPA) exposure is associated with nonalcoholic fatty liver disease. Disruption of autophagy causes lipid accumulation in hepatocytes. Whether and how BPA regulates autophagy remains to be explored. We investigated the effect of BPA on autophagy in hepatocytes and examined the influence of BPA-regulated autophagy on hepatic lipid accumulation. Male CD1 mice were treated with BPA for 8 weeks, followed by histological and biochemical evaluation of liver lipids and autophagy. Also, the effects of BPA on autophagy and hepatic lipid accumulation were examined in primary hepatocytes and HepG2 cells. Lipid content in HepG2 cells and/or primary hepatocytes was increased obviously after BPA exposure. In addition, BPA exposure caused accumulation of autophagosomes in HepG2 cells and enhanced colocalization of Bodipy 493/503 with microtubule associated protein light-chain 3. These changes were accompanied with increased expression levels of p-mammalian target of rapamycin, p-p70S6 kinase, p-ULK1 and decreased expression levels of Atg5. BPA exposure also downregulated the expression of cathepsin L and decreased cytoplasmic retention of acridine orange in HepG2 cells. The impaired autophagic degradation was further evidenced by increased levels of p62 in BPA-treated HepG2 cells. At the whole animal level, BPA treatment induced lipid accumulation in livers of male CD1 mice, which was accompanied with changes in hepatic autophagy-related proteins. Moreover, induction of autophagy by Torin1 protected against BPA-induced lipid accumulation whereas suppression of autophagy by chloroquine exacerbated BPA-induced lipid accumulation in HepG2 cells. BPA dysregulates autophagy in hepatocytes, which is linked to BPA-induced hepatic lipid accumulation.

Dysregulated Autophagy in Hepatocytes Promotes Bisphenol A-Induced Hepatic Lipid Accumulation in Male Mice.

Background/Aims: Serum cortisol level is elevated in patients with essential hypertension. We aimed at investigating the association of serum cortisol levels with parameters of renal function in essential hypertension. Methods: One hundred and seventy-eight patients with essential hypertension participated in the study. Fasting serum samples were collected at 8:00 am. Renal function was measured as estimated glomerular filtration rate (eGFR) calculated by the Chronic Kidney Disease Epidemiology Collaboration creatinine- cystatin C equation (eGFRcr-cys). Correlation analysis and stepwise regression analysis were used to detect the relationship between cortisol and eGFRcr-cys. The distributions of serum cortisol were split by the tertiles and subjects were stratified into those with low, median and high levels accordingly. Results: Serum cortisol levels were significantly higher in subjects whose eGFRcr-cys2 than subjects whose eGFRcr-cys>90 ml/min/1.73 m2 (394.0±93.4 vs. 343.2±98.4 nmol/L, P=0.001). Age, systolic blood pressure, and serum total cholesterol, uric acid, cortisol levels were significantly associated with eGFRcr-cys, serum levels of creatinine and cystatin C. After adjusting for clinical factors, serum cortisol level had a statistically significant negative association with the eGFRcr-cys (β=-0.19, P=0.027), and positive associations with cystatin C (β=0.31, P=0.001) and creatinine (β=0.14, P=0.044). With the increment of cortisol tertile, the eGFRcr-cys significantly decreased (93.18±14.36 vs. 84.61±14.67 vs. 81.29±12.36 ml/min/1.73 m2 for low, median and high tertile, respecively, P=0.001). Conclusion: Serum cortisol level was negatively correlated with eGFRcr-cys in subjects with essential hypertension. Further studies are needed to investigate whether cortisol plays a role in hypertensive nephropathy development.

/pdf/association-between-serum-cortisol-and-chronic-kidney-8rsxzy6ecr.pdf

Xiaojiao Xiang

Papers

Serum bisphenol A as a predictor of chronic kidney disease progression in primary hypertension: a 6-year prospective study.

Bisphenol A promotes hyperuricemia via activating xanthine oxidase

Dysregulated Autophagy in Hepatocytes Promotes Bisphenol A-Induced Hepatic Lipid Accumulation in Male Mice.

Association Between Serum Cortisol and Chronic Kidney Disease in Patients with Essential Hypertension