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Background: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure has been associated with metabolic diseases, however, the underlying molecular pathogenesis remains to be understood. Integrated PFAS and lipidomic analysis has the potential to identify alterations in lipid metabolism pathways for exposome research. Methods: A targeted LC-MS/MS method was developed for the quantification of 14 PFAS from human plasma samples (n = 96). Concurrently, high coverage lipidomics was conducted for the quantification of 665 lipid species in the same plasma samples. Linear regression models were implemented to study the association of PFAS with plasma lipidome. Results: Women had lower levels of PFAS compared to men and Asian-Indians had lower levels of PFAS compared to both Chinese and Malay subjects. PFAS were positively associated with a number of lipid species from lysophospholipid, ceramide and triacylglycerol lipid classes. Phosphatidylinositol, acylcarnitine and sphingosine-1-phosphate were negatively associated with PFAS. Association studies revealed both shared and distinct relationship of PFAS with plasma lipids. Conclusions: We demonstrate that the circulating levels of PFAS vary with age, ethnicity and sex within a multi-ethnic Asian population with potential implications in future biomonitoring and mitigation. Our comprehensive lipidomics methodology and association studies enabled us to characterize the relationship of circulating PFAS and lipidomic profiles. These results will help in better understanding of the molecular basis of PFAS exposure on human health outcomes. [ABSTRACT FROM AUTHOR]

Context Due to the essential role of carnitine as an intermediary in amino acid, carbohydrate, and lipid metabolism, a detailed characterization of circulating and urinary carnitine concentrations will aid in elucidating the molecular basis of impaired maternal metabolic flexibility and facilitating timely intervention for expectant mothers. Objective To investigate the association of maternal plasma and urinary free carnitine and acylcarnitines with cardiometabolic risk factors. Methods Liquid chromatography tandem mass spectrometry–based quantification of free carnitine and acylcarnitines (C2-C18) was performed on 765 plasma and 702 urine samples collected at preconception, 26 to 28 weeks' pregnancy, and 3 months postpartum in the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO) cohort study. Results Plasma concentrations of free carnitine and acylcarnitines decreased coupled with increased renal clearance in pregnancy compared with preconception and postpartum. Renal clearance of carnitine increased with an increase in prepregnancy body mass index (ppBMI) and gestational weight gain. Plasma short-chain acylcarnitines were positively associated with ppBMI, irrespective of the physiological state, while medium- and long-chain acylcarnitines were negatively associated with ppBMI at preconception and postpartum but showed a positive association in pregnancy. Similarly, plasma short-chain acylcarnitines were positively associated with Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) whereas medium- and long-chain acylcarnitines were negatively associated with HOMA-IR at preconception and in pregnancy. Mothers who developed gestational diabetes mellitus during pregnancy had ∼10% higher plasma propionylcarnitine concentration and ∼18% higher urine tiglylcarnitine concentration than mothers with normal glucose metabolism at preconception. Conclusion This study provides the metabolic and physiological basis of maternal carnitine homeostasis, which can be used in assessment of maternal cardiometabolic health at preconception to improve pregnancy outcomes. [ABSTRACT FROM AUTHOR]

Background: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure has been associated with metabolic diseases, however, the underlying molecular pathogenesis remains to be understood. Integrated PFAS and lipidomic analysis has the potential to identify alterations in lipid metabolism pathways for exposome research., Methods: A targeted LC-MS/MS method was developed for the quantification of 14 PFAS from human plasma samples (n = 96). Concurrently, high coverage lipidomics was conducted for the quantification of 665 lipid species in the same plasma samples. Linear regression models were implemented to study the association of PFAS with plasma lipidome., Results: Women had lower levels of PFAS compared to men and Asian-Indians had lower levels of PFAS compared to both Chinese and Malay subjects. PFAS were positively associated with a number of lipid species from lysophospholipid, ceramide and triacylglycerol lipid classes. Phosphatidylinositol, acylcarnitine and sphingosine-1-phosphate were negatively associated with PFAS. Association studies revealed both shared and distinct relationship of PFAS with plasma lipids., Conclusions: We demonstrate that the circulating levels of PFAS vary with age, ethnicity and sex within a multi-ethnic Asian population with potential implications in future biomonitoring and mitigation. Our comprehensive lipidomics methodology and association studies enabled us to characterize the relationship of circulating PFAS and lipidomic profiles. These results will help in better understanding of the molecular basis of PFAS exposure on human health outcomes., Competing Interests: Declarations. Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the respective Institutional Review Boards, DSRB for National University Hospital ((reference 2018/01167) and NUS-IRB (LH-20-024E) for National University of Singapore. All subjects gave their informed consent for inclusion before they participated in this study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Modulation of signaling pathways upon chronic arsenic exposure remains poorly studied. Here, we carried out SILAC-based quantitative phosphoproteomics analysis to dissect the signaling induced upon chronic arsenic exposure in human skin keratinocyte cell line, HaCaT. We identified 4171 unique phosphosites derived from 2000 proteins. We observed differential phosphorylation of 406 phosphosites (twofold) corresponding to 305 proteins. Several pathways involved in cytoskeleton maintenance and organization were found to be significantly enriched (p<0.05). Our data revealed altered phosphorylation of proteins associated with adherens junction remodeling and actin polymerization. Kinases such as protein kinase C iota type (PRKCI), mitogen-activated protein kinase kinase kinase 1 (MAP3K1), tyrosine-protein kinase BAZ1B (BAZ1B) and STE20 like kinase (SLK) were found to be hyperphosphorylated. Our study provides novel insights into signaling perturbations associated with chronic arsenic exposure in human skin keratinocytes. All MS/MS data have been deposited to the ProteomeXchange with identifier PXD004868., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)