Multiphoton In Vivo Microscopy of Embryonic Thrombopoiesis Reveals the Generation of Platelets through Budding

Authors

Huan Liu
Hellen Ishikawa-Ankerhold
Julia Winterhalter
Michael Lorenz
Mykhailo Vladymyrov
Steffen Massberg
Christian Schulz
Mathias Orban

Publication Date

10-6-2023

Journal

Cells

Abstract

Platelets are generated by specialized cells called megakaryocytes (MKs). However, MK's origin and platelet release mode have remained incompletely understood. Here, we established direct visualization of embryonic thrombopoiesis in vivo by combining multiphoton intravital microscopy (MP-IVM) with a fluorescence switch reporter mouse model under control of the platelet factor 4 promoter (Pf4CreRosa26mTmG). Using this microscopy tool, we discovered that fetal liver MKs provide higher thrombopoietic activity than yolk sac MKs. Mechanistically, fetal platelets were released from MKs either by membrane buds or the formation of proplatelets, with the former constituting the key process. In E14.5 c-Myb-deficient embryos that lack definitive hematopoiesis, MK and platelet numbers were similar to wild-type embryos, indicating the independence of embryonic thrombopoiesis from definitive hematopoiesis at this stage of development. In summary, our novel MP-IVM protocol allows the characterization of thrombopoiesis with high spatio-temporal resolution in the mouse embryo and has identified membrane budding as the main mechanism of fetal platelet production.

Keywords

Mice, Animals, Thrombopoiesis, Microscopy, Blood Platelets, Megakaryocytes, Platelet Count, megakaryocyte, multiphoton intravital microscopy, thrombopoiesis, yolk sac, fetal liver, c-Myb

Comments

Supplementary Materials

Data Availability Statement

PMID: 37830625