1
|
Lefrançais E, Ortiz-Muñoz G, Caudrillier A, Mallavia B, Liu F, Sayah DM, Thornton EE, Headley MB, David T, Coughlin SR, Krummel MF, Leavitt AD, Passegué E, Looney MR. The lung is a site of platelet biogenesis and a reservoir for haematopoietic progenitors. Nature 2017; 544:105-109. [PMID: 28329764 PMCID: PMC5663284 DOI: 10.1038/nature21706] [Citation(s) in RCA: 693] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 02/14/2017] [Indexed: 12/13/2022]
Abstract
Platelets are critical for haemostasis, thrombosis, and inflammatory responses, but the events that lead to mature platelet production remain incompletely understood. The bone marrow has been proposed to be a major site of platelet production, although there is indirect evidence that the lungs might also contribute to platelet biogenesis. Here, by directly imaging the lung microcirculation in mice, we show that a large number of megakaryocytes circulate through the lungs, where they dynamically release platelets. Megakaryocytes that release platelets in the lungs originate from extrapulmonary sites such as the bone marrow; we observed large megakaryocytes migrating out of the bone marrow space. The contribution of the lungs to platelet biogenesis is substantial, accounting for approximately 50% of total platelet production or 10 million platelets per hour. Furthermore, we identified populations of mature and immature megakaryocytes along with haematopoietic progenitors in the extravascular spaces of the lungs. Under conditions of thrombocytopenia and relative stem cell deficiency in the bone marrow, these progenitors can migrate out of the lungs, repopulate the bone marrow, completely reconstitute blood platelet counts, and contribute to multiple haematopoietic lineages. These results identify the lungs as a primary site of terminal platelet production and an organ with considerable haematopoietic potential.
Collapse
Affiliation(s)
- Emma Lefrançais
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Guadalupe Ortiz-Muñoz
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Axelle Caudrillier
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Beñat Mallavia
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Fengchun Liu
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - David M. Sayah
- Department of Medicine, University of California, Los Angeles (UCLA), Los Angeles, California 90095, USA
| | - Emily E. Thornton
- Department of Pathology, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Mark B. Headley
- Department of Pathology, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Tovo David
- Cardiovascular Research Institute, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Shaun R. Coughlin
- Cardiovascular Research Institute, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Matthew F. Krummel
- Department of Pathology, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Andrew D. Leavitt
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Emmanuelle Passegué
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| | - Mark R. Looney
- Department of Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
- Department of Laboratory Medicine, University of California, San Francisco (UCSF), San Francisco, California 94143, USA
| |
Collapse
|
2
|
Comparative analysis of human ex vivo-generated platelets vs megakaryocyte-generated platelets in mice: a cautionary tale. Blood 2015; 125:3627-36. [PMID: 25852052 DOI: 10.1182/blood-2014-08-593053] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 03/30/2015] [Indexed: 02/06/2023] Open
Abstract
Thrombopoiesis is the process by which megakaryocytes release platelets that circulate as uniform small, disc-shaped anucleate cytoplasmic fragments with critical roles in hemostasis and related biology. The exact mechanism of thrombopoiesis and the maturation pathways of platelets released into the circulation remain incompletely understood. We showed that ex vivo-generated murine megakaryocytes infused into mice release platelets within the pulmonary vasculature. Here we now show that infused human megakaryocytes also release platelets within the lungs of recipient mice. In addition, we observed a population of platelet-like particles (PLPs) in the infusate, which include platelets released during ex vivo growth conditions. By comparing these 2 platelet populations to human donor platelets, we found marked differences: platelets derived from infused megakaryocytes closely resembled infused donor platelets in morphology, size, and function. On the other hand, the PLP was a mixture of nonplatelet cellular fragments and nonuniform-sized, preactivated platelets mostly lacking surface CD42b that were rapidly cleared by macrophages. These data raise a cautionary note for the clinical use of human platelets released under standard ex vivo conditions. In contrast, human platelets released by intrapulmonary-entrapped megakaryocytes appear more physiologic in nature and nearly comparable to donor platelets for clinical application.
Collapse
|
4
|
Canals M, Atala C, Olivares R, Guajardo F, Figueroa DP, Sabat P, Rosenmann M. Functional and structural optimization of the respiratory system of the batTadarida brasiliensis(Chiroptera, Molossidae): does airway geometry matter? J Exp Biol 2005; 208:3987-95. [PMID: 16215224 DOI: 10.1242/jeb.01817] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYWe studied structure and function of the respiratory system in the bat Tadarida brasiliensis and compared it with those of two species of rodents, Abrothrix andinus and A. olivaceus. Tadarida brasiliensis had lower resting oxygen consumption, but higher maximum oxygen consumption and aerobic scope, than the rodents. The blood–gas barrier of the bat was thinner and its relative lung size was larger; however,alveolar surface density was similar among the three species. In consequence, T. brasiliensis has an oxygen diffusion capacity two or three times higher than that of the rodents. In Tadarida brasiliensis the characteristics of the lung were accompanied by geometrical changes in the proximal airway, such as high physical optimization as a consequence of small variations in the symmetry and the scaling ratio of the bronchial diameters. These may constitute an efficient way to save energy in respiratory mechanics and are the first report of airway adjustments to decrease entropy generation in bats.
Collapse
Affiliation(s)
- Mauricio Canals
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
| | | | | | | | | | | | | |
Collapse
|