Final Report Summary - MEIS1 & VASCULAR MK (Role of Meis1 in the embryonic megakaryocyte lineage and vascular development)
Project context and objectives
Our objective is to understand the role of the thrombocytic lineage in the development of the vasculature. In the reporting period we have established zebrafish as an equivalent animal model to mice for the analysis of the thrombocytic/embryonic megakaryocyte lineage function during vascular development, with the added advantage of real-time live imaging during embryonic development. We carried out a multi-disciplinary project, using genetic engineering, transgenic mice and fish animal models, genetics, in-vivo imaging, cell purification and transplantation to improve our understanding of the role of CD41 positive cells in the maturation of the vasculature.
Project results
Our top result can be described as a novel, not yet described, interaction between CD41 positive cells and venous sprouts that in turn will give origin to nascent lymphatics.
As such, this provided a clear and testable hypothesis for why several mutations that impair the development of blood lineages, more specifically of CD41 positive cells, also impair the formation of the lymphatic vasculature. Initially, we used Meis1 loss of function as a model for the depletion of the thrombocytic/embryonic megakaryocyte lineage in both fish and mice. The only hematopoietic defect found in Meis1 null mice is the absence of megakaryocytes and derived platelets; Meis1 null mice die between embryonic day 11.5 and 14.5 with internal haemorrhages and blood-filled lymphatics. Our novel interaction of CD41 cells with venous sprouts, which we first recorded in live time-lapse confocal microscopy in zebrafish embryos, simultaneously pinpoints the lineage responsible for the defects and a possible mechanism of action, thereby accomplishing a major objective of our proposal.
To further our understanding, we continued to probe this cellular interaction between CD41 cells and the endothelium, now with time and lineage controlled loss-of-function approaches and the use of genetic binary systems, such as the CRE-loxP and Gal4:UAS strategies that enable the depletion of the thrombocytic lineage while imaging CD41 positive cells and endothelial cell behaviour. The potential impact of this project is to identify a cell population capable of regulating the behaviour and fate of endothelial cells, which will open the door to clinical applications, and possible ways to target the vascular system and its regulation.
Our objective is to understand the role of the thrombocytic lineage in the development of the vasculature. In the reporting period we have established zebrafish as an equivalent animal model to mice for the analysis of the thrombocytic/embryonic megakaryocyte lineage function during vascular development, with the added advantage of real-time live imaging during embryonic development. We carried out a multi-disciplinary project, using genetic engineering, transgenic mice and fish animal models, genetics, in-vivo imaging, cell purification and transplantation to improve our understanding of the role of CD41 positive cells in the maturation of the vasculature.
Project results
Our top result can be described as a novel, not yet described, interaction between CD41 positive cells and venous sprouts that in turn will give origin to nascent lymphatics.
As such, this provided a clear and testable hypothesis for why several mutations that impair the development of blood lineages, more specifically of CD41 positive cells, also impair the formation of the lymphatic vasculature. Initially, we used Meis1 loss of function as a model for the depletion of the thrombocytic/embryonic megakaryocyte lineage in both fish and mice. The only hematopoietic defect found in Meis1 null mice is the absence of megakaryocytes and derived platelets; Meis1 null mice die between embryonic day 11.5 and 14.5 with internal haemorrhages and blood-filled lymphatics. Our novel interaction of CD41 cells with venous sprouts, which we first recorded in live time-lapse confocal microscopy in zebrafish embryos, simultaneously pinpoints the lineage responsible for the defects and a possible mechanism of action, thereby accomplishing a major objective of our proposal.
To further our understanding, we continued to probe this cellular interaction between CD41 cells and the endothelium, now with time and lineage controlled loss-of-function approaches and the use of genetic binary systems, such as the CRE-loxP and Gal4:UAS strategies that enable the depletion of the thrombocytic lineage while imaging CD41 positive cells and endothelial cell behaviour. The potential impact of this project is to identify a cell population capable of regulating the behaviour and fate of endothelial cells, which will open the door to clinical applications, and possible ways to target the vascular system and its regulation.
