A highly sensitive enzyme linked immunoadsorbent assay for determining retinol-binding protein in urine and serum is described. Commercially available reagents are used. The standard curve ranges from 1.2-24 micrograms/l, recovery of retinol-binding protein added to urine was 99-102% (n = 10) and dilution of urine was linear. The within-assay coefficient of variation ranged from 1.2-3.1% and the day-to-day coefficient of variation from 9.2-10.5% depending on concentration. The correlation with urinary retinol-binding protein determined by radioimmunoassay was good (n = 90, r = 0.95). In vitro experiments show that retinol-binding protein is stable in urine with pH 5.2.
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Curr Top Dev Biol
January 2025
Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, United States.
Alterations in tissue expression levels of both retinol-binding protein 2 (RBP2) and retinol-binding protein 4 (RBP4) have been associated with metabolic disease, specifically with obesity, glucose intolerance and hepatic steatosis. Our laboratories have shown that this involves novel pathways not previously considered as possible linkages between impaired retinoid metabolism and metabolic disease development. We have established both biochemically and structurally that RBP2 binds with very high affinity to very long-chain unsaturated 2-monoacylglycerols like the canonical endocannabinoid 2-arachidonoyl glycerol (2-AG) and other endocannabinoid-like substances.
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January 2025
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, United States. Electronic address:
Retinoids, particularly all-trans-retinoic acid (ATRA), play crucial roles in various physiological processes, including development, immune response, and reproduction, by regulating gene transcription through nuclear receptors. This review explores the biosynthetic pathways, homeostatic mechanisms, and the significance of retinoid-binding proteins in maintaining ATRA levels. It highlights the intricate balance required for ATRA homeostasis, emphasizing that both excess and deficiency can lead to severe developmental and health consequences.
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January 2025
Institute of Physical Chemistry, Polish Academy of Sciences , Warsaw, Poland.
The vertebrate visual cycle hinges on enzymatically converting all--retinol (at-ROL) into 11--retinal (11c-RAL), the chromophore that binds to opsins in photoreceptors, forming light-responsive pigments. When struck by a photon, these pigments activate the phototransduction pathway and initiate the process of vision. The enzymatic isomerization of at-ROL, crucial for restoring the visual pigments and preparing them to receive new light stimuli, relies on various enzymes found in both the photoreceptors and retinal pigment epithelium cells.
View Article and Find Full Text PDFFront Nephrol
January 2025
Department of Nephrology, Nephrology Vanderbilt Institute for Global Health (VIGH), Nashville, TN, United States.
Introduction: Antiretroviral therapy (ART) increases the life expectancy of persons living with HIV (PLWH), but not without potentially serious adverse effects. Tenofovir disoproxil fumarate (TDF) can cause nephrotoxicity, manifesting as acute kidney injury (AKI) that may persist after treatment discontinuation. Kidney injury biomarkers such as kidney injury molecule-1 (KIM-1), retinol-binding protein-4 (RBP-4), interleukin-18 (IL-18), and neutrophil gelatinase-associated lipocalin (NGAL) can aid early diagnosis and predict TDF-associated nephrotoxicity.
View Article and Find Full Text PDFPLoS Negl Trop Dis
January 2025
State Key Laboratory for Animal Disease Control and Prevention, Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China.
Fatty acid and retinol binding proteins (FARs) are lipid-binding protein that may be associated with modulating nematode pathogenicity to their hosts. However, the functional mechanism of FARs remains elusive. We attempt to study the function of a certain FAR that may be important in the development of Nippostrongylus brasiliensis.
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