Premium
Rapid Lysosome Fusion to Lipid Raft Clusters and Endothelial Dysfunction Mediated by VAMP‐2 in Coronary Arterial Endothelial Cells
Author(s) -
Han Weiqing,
Xia Min,
Zhang Fan,
Li Pinlan
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.814.1
Subject(s) - lysosome , microbiology and biotechnology , lipid raft , acid sphingomyelinase , chemistry , ceramide , sphingomyelin , biology , biochemistry , membrane , signal transduction , apoptosis , enzyme
Lysosome fusion mediates acid sphingomyelinase translocation to and activation in plasma membrane to form membrane lipid raft (LR) signaling in coronary arterial endothelial cells (CAECs). The molecular mechanism mediating this lysosome fusion to cell plasma, however, remains poorly understood. The present study attempted to evaluate whether vesicles associated membrane proteins‐2 (VAMP‐2) mediates lysosome fusion and LR clustering, leading to endothelial dysfunction in CAECs. By immunohistochemistry, VAMP‐2 was found to be abundantly expressed in the endothelium of bovine coronary arteries. Fluorescent confocal microscopy showed that VAMP‐2 was significantly aggregated with lysosome marker lamp‐1 and LRs when the CAECs were stimulated by FasL, a well‐known LR clustering stimulator. Using FM1‐43 quenching and dequenching technique, lysosome fusion to plasma membrane in response to FasL was blocked by VAMP‐2 inhibitor, tetanus toxin. In addition, fluorescence resonance energy transfer (FRET) detection demonstrated that Fas L‐induced FRET between LRs marker and VAMP‐2 increased by 21.2 ± 3.3 during FasL stimulation. Functionally, inhibition of VAMP‐2 significantly restored FasL‐induced endothelial dysfunction in coronary arterial rings. In conclusion, VAMP‐2 on lysosome membrane in CAECs is critical to the lysosome fusion to LR areas of plasma membrane in CAECs and this VAMP‐2‐mediated lysosome fusion may contributes to FasL‐induced endothelial dysfunction (Supported by NIH grants HL057244, HL091464 and HL075316).