Triggering role of acid sphingomyelinase in endothelial lysosome-membrane fusion and dysfunction in coronary arteries
- 1 March 2010
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Heart and Circulatory Physiology
- Vol. 298 (3), H992-H1002
- https://doi.org/10.1152/ajpheart.00958.2009
Abstract
The present study determined whether activation of acid sphingomyelinase (ASM) drives membrane proximal lysosomes to fuse to the cell surface, facilitating membrane lipid rafts (LRs) clustering in coronary arterial endothelial cells (CAECs) and leading to endothelial dysfunction. By confocal microscopy, the activators of ASM, phosphatidylinositol (PI), and bis (monoacylglyceryl) phosphate (Bis), and an inducer of ASM, butyrate, were found to increase LRs clustering in bovine CAECs, which was blocked by lysosome fusion inhibitor vacuolin-1. However, arsenic trioxide (Ars), an inducer of de novo synthesis of ceramide, had no such effect. Similarly, vacuolin-1-blockable effects were observed using fluorescence resonance energy transfer detection. Liquid chromatography-electrospray ionization-tandem mass spectrometry analysis demonstrated that all of these treatments, even Ars, increased ceramide production in CAECs. When ASM gene was silenced, all treatments except Ars no longer increased ceramide levels. Furthermore, dynamic fluorescence monitoring in live cells showed that PI and Bis stimulated lysosome-membrane fusion in CAECs. Functionally, PI and Bis impaired endothelium-dependent vasodilation in perfused coronary arteries, which was blocked by vacuolin-1 and a lysosome function inhibitor, bafilomycine. FasL (Fas ligand), a previously confirmed lysosome fusion stimulator as a comparison, also produced a similar effect. It is concluded that ASM activation serves as a triggering mechanism and driving force, leading to fusion of membrane proximal lysosomes into LR clusters on the cell membrane of CAECs, which represents a novel mechanism mediating endothelial dysfunction during death receptor activation or other pathological situation.Keywords
This publication has 42 references indexed in Scilit:
- Fusogenicity of membranes: The impact of acid sphingomyelinase on innate immune responsesImmunobiology, 2008
- Critical Role of Lipid Raft Redox Signaling Platforms in Endostatin-Induced Coronary Endothelial DysfunctionArteriosclerosis, Thrombosis, and Vascular Biology, 2008
- Principles of bioactive lipid signalling: lessons from sphingolipidsNature Reviews Molecular Cell Biology, 2008
- Arterial Structural Changes in Hypertension: A Consideration of Methodology, Terminology and Functional ConsequenceJournal of Vascular Research, 2003
- Aberrant sphingomyelin/ceramide metabolic-induced neuronal endosomal/lysosomal dysfunction: potential pathological consequences in age-related neurodegenerationAdvanced Drug Delivery Reviews, 2003
- Apoptotic, non-apoptotic, and anti-apoptotic pathways of tumor necrosis factor signallingBiochemical Pharmacology, 1998
- Kinetics and regulation of fast endocytosis at hippocampal synapsesNature, 1998
- Involvement of de NovoCeramide Biosynthesis in Tumor Necrosis Factor-α/Cycloheximide-induced Cerebral Endothelial Cell DeathPublished by Elsevier BV ,1998
- Morphological changes induced by phospholipase C and by sphingomyelinase on large unilamellar vesicles: a cryo-transmission electron microscopy study of liposome fusionBiophysical Journal, 1997
- Different Effects of Enzyme-generated Ceramides and Diacylglycerols in Phospholipid Membrane Fusion and LeakagePublished by Elsevier BV ,1996