| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Received June 26, 2002
Accepted after revision August 13, 2002
1 University of Ljubljana, Department of Biology, Vecna Pot 111, 1001 Ljubljana, POB 2995, Slovenia
2 National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
3 Department of Veterinary Basic Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK
4 Department of Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
* To whom correspondence should be addressed. E-mail: t.carter{at}ucl.ac.uk.
Endothelial cells secrete a range of procoagulant, anticoagulant and inflammatory proteins by exocytosis to regulate blood clotting and local immune responses. The mechanisms regulating vesicular exocytosis were studied in human umbilical vein endothelial cells (HUVEC) with high-resolution membrane capacitance (Cm) measurements. The total whole-cell Cm and the amplitudes and times of discrete femtoFarad (fF)-sized Cm steps due to exocytosis and endocytosis were monitored simultaneously. Intracellular calcium concentration [Ca2+]i was elevated by flash photolysis of intracellular calcium-DM-nitrophen to evoke secretion and monitored with the low-affinity Ca2+ indicator furaptra. Sustained elevation of [Ca2+]i to > 20 µM evoked large, slow increases in Cm of up to 5 pF in 1-2 min. Exocytotic and endocytotic steps of amplitude 0.5-110 fF were resolved, and accounted on average for ~33 % of the total Cm change. A prominent component of Cm steps of 2.5-9.0 fF was seen and could be attributed to exocytosis of von-Willebrand-factor-containing Weibel-Palade bodies (WPb), based on the near-identical distributions of capacitance step amplitudes, with calculated estimates of WPb capacitance based on morphometry, and on the absence of 2.5-9.0 fF Cm steps in cells deficient in WPb. WPb secretion was delayed on average by 23 s after [Ca2+]i elevation, whereas total Cm increased immediately due to the secretion of small, non-WPb granules. The results show that following a large increase of [Ca2+]i, corresponding to strong stimulation, small vesicular components are immediately available for secretion, whereas the large WPb undergo exocytosis only after a delay. The presence of events of magnitude 9-110 fF also provides evidence of compound secretion of WPb due to prior fusion of individual granules.
This article has been cited by other articles:
|
|
 |
|
  V. Babich, A. Meli, L. Knipe, J. E. Dempster, P. Skehel, M. J. Hannah, and T. Carter Selective release of molecules from Weibel-Palade bodies during a lingering kiss Blood, June 1, 2008; 111(11): 5282 - 5290. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Erent, A. Meli, N. Moisoi, V. Babich, M. J. Hannah, P. Skehel, L. Knipe, G. Zupancic, D. Ogden, and T. Carter Rate, extent and concentration dependence of histamine-evoked Weibel Palade body exocytosis determined from individual fusion events in human endothelial cells J. Physiol., August 15, 2007; 583(1): 195 - 212. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Oynebraten, N. Barois, K. Hagelsteen, F.-E. Johansen, O. Bakke, and G. Haraldsen Characterization of a Novel Chemokine-Containing Storage Granule in Endothelial Cells: Evidence for Preferential Exocytosis Mediated by Protein Kinase A and Diacylglycerol J. Immunol., October 15, 2005; 175(8): 5358 - 5369. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Hannah, P. Skehel, M. Erent, L. Knipe, D. Ogden, and T. Carter Differential Kinetics of Cell Surface Loss of von Willebrand Factor and Its Propolypeptide after Secretion from Weibel-Palade Bodies in Living Human Endothelial Cells J. Biol. Chem., June 17, 2005; 280(24): 22827 - 22830. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Oynebraten, O. Bakke, P. Brandtzaeg, F.-E. Johansen, and G. Haraldsen Rapid chemokine secretion from endothelial cells originates from 2 distinct compartments Blood, July 15, 2004; 104(2): 314 - 320. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-B. Manneville, S. Etienne-Manneville, P. Skehel, T. Carter, D. Ogden, and M. Ferenczi Interaction of the actin cytoskeleton with microtubules regulates secretory organelle movement near the plasma membrane in human endothelial cells J. Cell Sci., October 1, 2003; 116(19): 3927 - 3938. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
