Inhibition of UDP-glucuronosyltransferases (UGTs) by phthalate monoesters.

Chemosphere

Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China. Electronic address:

Published: April 2018

Phthalate monoesters are important metabolites of phthalate esters (PAEs) which have been extensively utilized in industry. This study aims to investigate the inhibition of phthalate monoesters on the activity of various isoforms of UDP-glucuronosyltransferases (UGTs), trying to elucidate the toxicity mechanism of environmental endocrine disruptors from the new perspectives. In vitro recombinant UGTs-catalyzed glucuronidation of 4-methylumbelliferone (4-MU) was employed to evaluate 8 kinds of phthalate monoesters on 11 sorts of main human UGT isoforms. 100 μM phthalate monoesters exhibited negligible inhibition towards the activity of UGT1A1, UGT1A3, UGT1A6, UGT1A8, UGT1A10, UGT2B4, UGT2B7, UGT2B15 and UGT2B17. The activity of UGT1A7 was strongly inhibited by monoethylhexyl phthalate (MEHP), but slightly inhibited by all the other phthalate monoesters. UGT1A9 was broadly inhibited by monobenzyl phthalate (MBZP), monocyclohexyl phthalate (MCHP), MEHP, monohexyl phthalate (MHP) and monooctyl phthalate (MOP), respectively. MEHP exhibited competitive inhibition towards UGT1A7, and MBZP, MCHP, MEHP, MHP and MOP showed competitive inhibition towards UGT1A9. The inhibition kinetic parameters (K) were calculated to be 11.25 μM for MEHP-UGT1A7, and 2.13, 0.09, 1.17, 7.47, 0.16 μM for MBZP-UGT1A9, MCHP-UGT1A9, MEHP-UGT1A9, MHP-UGT1A9, MOP-UGT1A9, respectively. Molecular docking indicated that both hydrogen bonds formation and hydrophobic interactions significantly contributed to the interaction between phthalate monoesters and UGT isoforms. All these information will be beneficial for understanding the adverse effects of PAEs.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2018.01.010DOI Listing

Publication Analysis

Top Keywords

phthalate monoesters
28
phthalate
13
udp-glucuronosyltransferases ugts
8
ugt isoforms
8
mchp mehp
8
competitive inhibition
8
monoesters
7
inhibition
6
inhibition udp-glucuronosyltransferases
4
ugts phthalate
4

Similar Publications

Mechanistic and structural insights into EstS1 esterase: A potent broad-spectrum phthalate diester degrading enzyme.

Structure

November 2024

Department of Biosciences and Bioengineering, IIT Roorkee, Roorkee, Uttarakhand 247667, India. Electronic address:

Phthalate diesters are important pollutants and act as endocrine disruptors. While certain bacterial esterases have been identified for phthalate diesters degradation to monoesters, their structural and mechanistic characteristics remain largely unexplored. Here, we highlight the potential of the thermostable and pH-tolerant EstS1 esterase from Sulfobacillus acidophilus DSM10332 to degrade high molecular weight bis(2-ethylhexyl) phthalate (DEHP) by combining biophysical and biochemical approaches along with high-resolution EstS1 crystal structures of the apo form and with bound substrates, products, and their analogs to elucidate its mechanism.

View Article and Find Full Text PDF

Combined effects and potential mechanisms of phthalate metabolites on serum sex hormones among reproductive-aged women: An integrated epidemiology and computational toxicology study.

Ecotoxicol Environ Saf

December 2024

Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China; College of New Energy and Environment, Jilin University, Changchun 130012, China.

The reproductive age is a crucial stage for women to bear offspring. However, reproductive-aged women are simultaneously exposed to various phthalates, which may pose a threat to their reproductive health. This study employed generalized linear regression and weighted quantile sum (WQS) regression to explore the associations between monoesters of phthalates (MPAEs) and sex hormones in 913 reproductive-aged women in the National Health and Nutrition Examination Survey.

View Article and Find Full Text PDF

Resveratrol alleviates Mono-2-ethylhexyl phthalate-induced mitophagy, ferroptosis, and immunological dysfunction in grass carp hepatocytes by regulating the Nrf2 pathway.

J Environ Manage

December 2024

College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China; Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin, 150030, China. Electronic address:

Mono-2-ethylhexyl phthalate (MEHP) is the major biologically active metabolite of Di(2-ethylhexyl) phthalate (DEHP). This MEHP mono-ester metabolite can be transported through the bloodstream into tissues such as the liver, kidneys, fat, and testes and cause corresponding damage. Resveratrol (RSV) has anti-inflammatory, antioxidant, and detoxification characteristics.

View Article and Find Full Text PDF

Phthalate monoesters affect membrane fluidity and cell-cell contacts in endometrial stromal adherent cell lines and spheroids.

Reprod Toxicol

December 2024

Competence Centre on Health Technologies, Tartu, Estonia; Department of Obstetrics and Gynaecology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia; Division of Obstetrics and Gynaecology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden; Department of Gynaecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden.

Phthalate monoesters have been identified as endocrine disruptors in a variety of models, yet understanding of their exact mechanisms of action and molecular targets in cells remains incomplete. Here, we set to determine whether epidemiologically relevant mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) can affect biological processes by altering cell plasma membrane fluidity or formation of cell-cell contacts. As a model system, we chose endometrial stromal cell lines, one of which was previously used in a transcriptomic study with MEHHP or MEHHP-containing mixtures.

View Article and Find Full Text PDF

Phthalates are a class of known endocrine-disrupting chemicals that are found in common everyday products. Several studies associate phthalate exposure with detrimental effects on ovarian function, including growth and development of the follicle and production of steroid hormones. We hypothesized that dysregulation of the ovary by phthalates may be mediated by phthalate toxicity towards granulosa cells, a major cell type in ovarian follicles responsible for key steps of hormone production and nourishing the developing oocyte.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!