Scope: Maillard reaction products (MRPs) are believed to interact with the receptor for advanced glycation endproducts (RAGE) and lead to a pro-inflammatory cellular response. The structural basis for this interaction is scarcely understood. This study investigates the effect of individual lysine modifications in free form or bound to casein on human colon cancer cells.
Methods And Results: Selectively glycated casein containing either protein-bound N-ε-carboxymethyllysine (CML), N-ε-fructosyllysine (FL), or pyrraline is prepared and up to 94%, 97%, and 61% of lysine modification could be attributed to CML, FL, or pyrraline, respectively. HCT 116 cells are treated with free CML, pyrraline, FL, or modified casein for 24 h. Native casein is used as control. Intracellular MRP content is analyzed by UPLC-MS/MS. Microscopic analysis of the transcription factors shows no activation of NFκB by free or protein-bound FL or CML, whereas casein containing protein-bound pyrraline activates Nrf2. RAGE expression is not influenced by free or casein-bound MRPs. Activation of Nrf2 by pyrraline-modified casein is confirmed by analyzing Nrf2 target proteins NAD(P)H dehydrogenase (quinone 1) (NQO1) and heme oxygenase-1 (HO-1).
Conclusion: Studies on the biological effects of glycated proteins require an individual consideration of defined structures. General statements on the effect of "AGEs" in biological systems are scientifically unsound.
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http://dx.doi.org/10.1002/mnfr.202300137 | DOI Listing |
Cold Spring Harb Protoc
December 2024
Christopher S. Bond Life Sciences Center, Division of Biological Sciences, Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211, USA
Amino acids in maize can exist in both a free and protein-bound state. While most amino acids are part of a protein backbone, a small percentage of them remain free and play important biological roles, serving as signaling molecules, nitrogen transporters, osmolytes, and precursors for multiple primary and secondary metabolites. Their levels vary widely especially in maize leaves, depending on the developmental stage and in response to environmental conditions.
View Article and Find Full Text PDFObjective: Pergolide, labeled for the treatment of pituitary pars intermedia dysfunction, is 90% protein bound and might cause a decrease in blood thyroid hormone concentrations by displacing them from binding proteins. This study investigated the effect of pergolide on the equine thyroid function.
Methods: This was an analytic, observational, cohort study.
Mol Imaging Biol
December 2024
Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, M13 9PL, UK.
Purpose: Protein synthesis is essential to maintain integrity and function of the human brain, and protein synthesis is associated specifically with the formation of long-term memory. Experimental and clinical observations indicate that this process is disturbed in Alzheimer's dementia and other neurodegenerative diseases. In-vivo investigation with positron emission tomography (PET) using [C]leucine provides a unique possibility to measure regional cerebral protein synthesis (rCPS) rates in human brain and to determine whether it is altered in Alzheimer's disease (AD), and thus may provide a target for future therapeutic interventions.
View Article and Find Full Text PDFESC Heart Fail
November 2024
Department of Clinical Sciences and Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Background And Aims: The heart is a metabolic organ rich in mitochondria. The failing heart reprograms to utilize different energy substrates, which increase its oxygen consumption. These adaptive changes contribute to increased oxidative stress.
View Article and Find Full Text PDFHeliyon
October 2024
Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, PR China.
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