Scanning electron microscopy study of neutrophil membrane tubulovesicular extensions (cytonemes) and their role in anchoring, aggregation and phagocytosis. The effect of nitric oxide.
We have shown that human neutrophils develop dynamic thin and very long tubulovesicular extensions (cytonemes) upon adhesion to fibronectin, if cell spreading was blocked by Na(+)-free medium or by 4-bromophenacyl bromide, N-ethylmaleimide, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole and cytochalasin D (S. I. Galkina, G. F. Sud'ina and V. Ullrich, (2001). Exp. Cell Res. 266, 222-228). In the present work we found that similar in size and behavior tubulovesicular extensions were formed on the neutrophil cell bodies upon adhesion to fibronectin-coated substrata in the presence of the nitric oxide donor diethylamine NONOate. In the presence of the nitric oxide synthase inhibitor N-omega-nitro-L-arginine methyl ester, neutrophils were well spread and had no microextensions. Using scanning electron microscopy, we demonstrated that tubulovesicular extensions of neutrophils executed long-range adhesion and binding objects for phagocytosis, such as serum-opsonized zymosan particles and erythrocytes. Tubulovesicular extensions anchored neutrophils to substrata in a beta1 and beta2 integrin-independent, but L-selectin-dependent manner. BODIPY-sphingomyelin impaired development of tubulovesicular extension, and heparitinase 1 played a role in their destruction. Membrane tubulovesicular extensions are supposed to represent protrusions of an intracellular exocytotic traffic and serve as cellular sensory and adhesive organelles. Nitric oxide seems to play a role in regulation of tubulovesicular extensions formation, thus affecting neutrophil adhesive interactions and phagocytosis.
Galkina
Svetlana I
SI
A. N. Belozersky Institute of Physico-Chemical Biology of the M. V. Lomonosov Moscow State University, 119992, Moscow, Leninskie gory, Building A, Moscow, Russia. galkina@genebee.msu.ru
Molotkovsky
Julian G
JG
Ullrich
Volker
V
Sud'ina
Galina F
GF
D001896:Boron Compounds / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002449:Cell Aggregation / Q000187:drug effects / Q000502:physiology; D022081:Cell Surface Extensions / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis / Q000502:physiology; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D009569:Nitric Oxide / Q000494:pharmacology / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D015388:Organelles / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D015815:Cell Adhesion Molecules; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase