The accumulation of free cholesterol in macrophage lysosomes significantly enhances atherogenesis. Our recent study demonstrated that the cluster of differentiation 38 (CD38)/nicotinic acid adenine dinucleotide phosphate (NAADP)/Ca signaling pathway plays a critical role in the efflux of lysosomal free cholesterol from macrophages in atherosclerosis. Niacin, known as nicotinic acid, is one of the oldest lipid-lowering medications showing unique anti-atherosclerotic activity. However, it is unknown whether this anti-atherosclerosis activity is associated with the efflux of lysosomal compartmentalized cholesterol in macrophages. In this study, we investigated the anti-atherosclerotic effects of niacin on the reduction of lysosomal free cholesterol via CD38/NAADP signaling in macrophages derived from low-density lipoprotein receptor (LDLr) mice. Fluorescent filipin and Nile red labeling coupled with confocal microscopy demonstrated that niacin reduced free cholesterol accumulation in lysosomes in a concentration-dependent manner. Transmission electron microscopy also showed that niacin markedly decreased cholesterol crystal formation in lysosomes in oxidized LDL-containing LDLr bone marrow-derived macrophages. Enzyme-linked immunosorbent assays showed that niacin increased NAADP production in a concentration-dependent manner, which was inhibited by small interfering RNA interference of CD38. Therefore, niacin may promote the efflux of lysosomal cholesterol from macrophages via the CD38/NAADP signaling pathway.
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http://dx.doi.org/10.1177/15353702221084632 | DOI Listing |
J Pathol
January 2025
Graduate Institute of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan.
Osteosarcoma is an aggressive bone malignancy with a high propensity for drug resistance and metastasis, leading to poor clinical outcomes. This study investigates the role of core 1 β1,3-galactosyltransferase 1 (C1GALT1) in osteosarcoma, focusing on its implications in chemoresistance. Our findings reveal that high expression of C1GALT1 is associated with advanced stages, adverse overall survival, and increased recurrence rates.
View Article and Find Full Text PDFLipids Health Dis
January 2025
The State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, 510060, China.
Clinical studies have suggested that tirzepatide may also possess hepatoprotective effects; however, the molecular mechanisms underlying this association remain unclear. In our study, we performed biochemical analyses of serum and histopathological examinations of liver tissue in mice. To preliminarily explore the molecular mechanisms of tirzepatide on metabolic dysfunction-associated fatty liver disease (MAFLD), liquid chromatography-mass spectrometry (LC-MS) was employed for comprehensive metabolomic, lipidomic, and proteomic analyses in MAFLD mice fed a high-fat diet (HFD).
View Article and Find Full Text PDFImmunopharmacol Immunotoxicol
January 2025
Tobacco and Health Research Center, Endocrinology and Metabolism Research Center, Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
Traumatic brain injury (TBI) precipitates a neuroinflammatory cascade, with the NLRP3 inflammasome emerging as a critical mediator. This review scrutinizes the complex activation pathways of the NLRP3 inflammasome by underscoring the intricate interplay between calcium signaling, mitochondrial disturbances, redox imbalances, lysosomal integrity, and autophagy. It is hypothesized that a combination therapy approach-integrating NF-κB pathway inhibitors with NLRP3 inflammasome antagonists-holds the potential to synergistically dampen the inflammatory storm associated with TBI.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390.
Spns1 mediates the rate-limiting efflux of lysophospholipids from the lysosome to the cytosol. Deficiency of Spns1 is associated with embryonic senescence, as well as liver and skeletal muscle atrophy in animal models. However, the mechanisms by which Spns1 transports lysophospholipid and proton sensing remain unclear.
View Article and Find Full Text PDFBMC Biol
December 2024
Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290, Helsinki, Finland.
Background: Many members of the oxysterol-binding protein-related protein (ORP) family have been characterized in detail over the past decades, but the lipid transport and other functions of ORP7 still remain elusive. What is known about ORP7 points toward an endoplasmic reticulum and plasma membrane-localized protein, which also interacts with GABA type A receptor-associated protein like 2 (GABARAPL2) and unlipidated Microtubule-associated proteins 1A/1B light chain 3B (LC3B), suggesting a further autophagosomal/lysosomal association. Functional roles of ORP7 have been suggested in cholesterol efflux, hypercholesterolemia, and macroautophagy.
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