Dynamic visualization of thrombopoiesis within bone marrow.
Platelets are generated from megakaryocytes (MKs) in mammalian bone marrow (BM) by mechanisms that remain poorly understood. Here we describe the use of multiphoton intravital microscopy in intact BM to visualize platelet generation in mice. MKs were observed as sessile cells that extended dynamic proplatelet-like protrusions into microvessels. These intravascular extensions appeared to be sheared from their transendothelial stems by flowing blood, resulting in the appearance of proplatelets in peripheral blood. In vitro, proplatelet production from differentiating MKs was enhanced by fluid shear. These results confirm the concept of proplatelet formation in vivo and are consistent with the possibility that blood flow-induced hydrodynamic shear stress is a biophysical determinant of thrombopoiesis.
Junt
Tobias
T
Immune Disease Institute and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
Schulze
Harald
H
Chen
Zhao
Z
Massberg
Steffen
S
Goerge
Tobias
T
Krueger
Andreas
A
Wagner
Denisa D
DD
Graf
Thomas
T
Italiano
Joseph E
JE
Shivdasani
Ramesh A
RA
von Andrian
Ulrich H
UH
D000818:Animals; D001426:Bacterial Proteins; D001792:Blood Platelets / Q000166:cytology*; D001853:Bone Marrow / Q000502:physiology*; D002478:Cells, Cultured; D008164:Luminescent Proteins; D008533:Megakaryocytes / Q000166:cytology*; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton; D040201:Platelet Membrane Glycoprotein IIb; D033081:Shear Strength; D034061:Thrombopoiesis / Q000502:physiology*
D001426:Bacterial Proteins; D008164:Luminescent Proteins; D040201:Platelet Membrane Glycoprotein IIb; C054562:yellow fluorescent protein, Bacteria