VAMP-8 segregates mast cell-preformed mediator exocytosis from cytokine trafficking pathways.
Inflammatory responses by mast cells are characterized by massive exocytosis of prestored granular mediators followed by cytokine/chemokine release. The vesicular trafficking mechanisms involved remain poorly understood. Vesicular-associated membrane protein-8 (VAMP-8), a member of the soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) family of fusion proteins initially characterized in endosomal and endosomal-lysosomal fusion, may also function in regulated exocytosis. Here we show that in bone marrow-derived mast cells (BMMCs) VAMP-8 partially colocalized with secretory granules and redistributed upon stimulation. This was associated with increased SNARE complex formation with the target t-SNAREs, SNAP-23 and syntaxin-4. VAMP-8-deficient BMMCs exhibited a markedly reduced degranulation response after IgE+ antigen-, thapsigargin-, or ionomycin-induced stimulation. VAMP-8-deficient mice also showed reduced plasma histamine levels in passive systemic anaphylaxis experiments, while cytokine/chemokine release was not affected. Unprocessed TNF accumulated at the plasma membrane where it colocalized with a VAMP-3-positive vesicular compartment but not with VAMP-8. The findings demonstrate that VAMP-8 segregates secretory lysosomal granule exocytosis in mast cells from cytokine/chemokine molecular trafficking pathways.
Tiwari
Neeraj
N
Inserm U699, Paris, France.
Wang
Cheng-Chun
CC
Brochetta
Cristiana
C
Ke
Gou
G
Vita
Francesca
F
Qi
Zeng
Z
Rivera
Juan
J
Soranzo
Maria Rosa
MR
Zabucchi
Giuliano
G
Hong
Wanjin
W
Blank
Ulrich
U
D000707:Anaphylaxis / Q000235:genetics / Q000276:immunology / Q000473:pathology; D000818:Animals; D000941:Antigens / Q000276:immunology; D015550:Cell Degranulation / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D016207:Cytokines / Q000235:genetics / Q000276:immunology*; D005089:Exocytosis / Q000235:genetics / Q000276:immunology*; D006632:Histamine / Q000235:genetics / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007249:Inflammation / Q000235:genetics / Q000276:immunology; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology; D008247:Lysosomes / Q000235:genetics / Q000276:immunology / Q000473:pathology; D008407:Mast Cells / Q000276:immunology* / Q000473:pathology; D008561:Membrane Fusion / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D021381:Protein Transport / Q000235:genetics / Q000276:immunology; D050765:Qa-SNARE Proteins / Q000235:genetics / Q000276:immunology; D050766:Qb-SNARE Proteins / Q000235:genetics / Q000276:immunology; D050683:R-SNARE Proteins / Q000235:genetics / Q000276:immunology*; D022142:Secretory Vesicles / Q000235:genetics / Q000276:immunology / Q000473:pathology; D019284:Thapsigargin / Q000494:pharmacology
D000941:Antigens; D016207:Cytokines; D007476:Ionophores; D007783:Lactones; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050683:R-SNARE Proteins; C491831:Vamp8 protein, mouse; D007073:Immunoglobulin E; D015759:Ionomycin; D019284:Thapsigargin; D006632:Histamine