Generation of dorsal aorta hemogenic endothelium involves replacement of the ventral aortic lining with cells derived from the coelomic epithelium

Abstract

BackgroundThe ventral wall of the dorsal aorta is the earliest known embryonic location of definitive hematopoiesis. The developmental processes that generate this hemogenic endothelium are not well understood. The Coelomic Epithelium (CE) is an epithelial layer that lines the embryonic body cavity and invests the external surface of the viscera. Here we present evidence that the CE can give rise to hemogenic endothelium of the dorsal aortaMethodsWe used two cell tracking techniques in order to trace the fate of coelomic epithelial cells in the chick embryo. In the first approach, the fluorescent vital dye CM-DiI was microinjected into the coelomic cavity. In the second approach, a plasmid expressing eGFP was electroporated into the cells of the coelomic lining. The fate of labeled cells was analyzed after up to 48 hours of incubation by immunofluorescence for the cell label and for cell-specific markers, including the blood cell marker cd45ResultsCoelomic epithelium-derived cells were found to incorporate into the ventral wall of the dorsal aorta, some of which were observed to differentiate into clusters of cd-45-expressing hematopoietic cells. These results indicate that the aortic hemogenic endothelium is generated by a process that involves replacement of the ventral aortic endothelium by coelomic epithelium-derived cells that have hemogenic potential. BackgroundThe ventral wall of the dorsal aorta is the earliest known embryonic location of definitive hematopoiesis. The developmental processes that generate this hemogenic endothelium are not well understood. The Coelomic Epithelium (CE) is an epithelial layer that lines the embryonic body cavity and invests the external surface of the viscera. Here we present evidence that the CE can give rise to hemogenic endothelium of the dorsal aorta The ventral wall of the dorsal aorta is the earliest known embryonic location of definitive hematopoiesis. The developmental processes that generate this hemogenic endothelium are not well understood. The Coelomic Epithelium (CE) is an epithelial layer that lines the embryonic body cavity and invests the external surface of the viscera. Here we present evidence that the CE can give rise to hemogenic endothelium of the dorsal aorta MethodsWe used two cell tracking techniques in order to trace the fate of coelomic epithelial cells in the chick embryo. In the first approach, the fluorescent vital dye CM-DiI was microinjected into the coelomic cavity. In the second approach, a plasmid expressing eGFP was electroporated into the cells of the coelomic lining. The fate of labeled cells was analyzed after up to 48 hours of incubation by immunofluorescence for the cell label and for cell-specific markers, including the blood cell marker cd45 We used two cell tracking techniques in order to trace the fate of coelomic epithelial cells in the chick embryo. In the first approach, the fluorescent vital dye CM-DiI was microinjected into the coelomic cavity. In the second approach, a plasmid expressing eGFP was electroporated into the cells of the coelomic lining. The fate of labeled cells was analyzed after up to 48 hours of incubation by immunofluorescence for the cell label and for cell-specific markers, including the blood cell marker cd45 ResultsCoelomic epithelium-derived cells were found to incorporate into the ventral wall of the dorsal aorta, some of which were observed to differentiate into clusters of cd-45-expressing hematopoietic cells. These results indicate that the aortic hemogenic endothelium is generated by a process that involves replacement of the ventral aortic endothelium by coelomic epithelium-derived cells that have hemogenic potential. Coelomic epithelium-derived cells were found to incorporate into the ventral wall of the dorsal aorta, some of which were observed to differentiate into clusters of cd-45-expressing hematopoietic cells. These results indicate that the aortic hemogenic endothelium is generated by a process that involves replacement of the ventral aortic endothelium by coelomic epithelium-derived cells that have hemogenic potential.