Browsing by Author "Daniel, Andrea R"

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    Intravital imaging of mouse embryos
    (Science, 2020-04-10) Huang, Qiang; Cohen, Malkiel A; Alsina, Fernando C; Devlin, Garth; Garrett, Aliesha; McKey, Jennifer; Havlik, Patrick; Rakhilin, Nikolai; Wang, Ergang; Xiang, Kun; Mathews, Parker; Wang, Lihua; Bock, Cheryl; Ruthig, Victor; Wang, Yi; Negrete, Marcos; Wong, Chi Wut; Murthy, Preetish KL; Zhang, Shupei; Daniel, Andrea R; Kirsch, David G; Kang, Yubin; Capel, Blanche; Asokan, Aravind; Silver, Debra L; Jaenisch, Rudolf; Shen, Xiling
    Embryonic development is a complex process that is unamenable to direct observation. In this study, we implanted a window to the mouse uterus to visualize the developing embryo from embryonic day 9.5 to birth. This removable intravital window allowed manipulation and high-resolution imaging. In live mouse embryos, we observed transient neurotransmission and early vascularization of neural crest cell (NCC)–derived perivascular cells in the brain, autophagy in the retina, viral gene delivery, and chemical diffusion through the placenta. We combined the imaging window with in utero electroporation to label and track cell division and movement within embryos and observed that clusters of mouse NCC-derived cells expanded in interspecies chimeras, whereas adjacent human donor NCC-derived cells shrank. This technique can be combined with various tissue manipulation and microscopy methods to study the processes of development at unprecedented spatiotemporal resolution.
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    Sensitization of Vascular Endothelial Cells to Ionizing Radiation Promotes the Development of Delayed Intestinal Injury in Mice.
    (Radiation research, 2019-09) Lee, Chang-Lung; Daniel, Andrea R; Holbrook, Matt; Brownstein, Jeremy; Silva Campos, Lorraine Da; Hasapis, Stephanie; Ma, Yan; Borst, Luke B; Badea, Cristian T; Kirsch, David G
    Exposure of the gastrointestinal (GI) tract to ionizing radiation can cause acute and delayed injury. However, critical cellular targets that regulate the development of radiation-induced GI injury remain incompletely understood. Here, we investigated the role of vascular endothelial cells in controlling acute and delayed GI injury after total-abdominal irradiation (TAI). To address this, we used genetically engineered mice in which endothelial cells are sensitized to radiation due to the deletion of the tumor suppressor p53. Remarkably, we found that VE-cadherin-Cre; p53FL/FL mice, in which both alleles of p53 are deleted in endothelial cells, were not sensitized to the acute GI radiation syndrome, but these mice were highly susceptible to delayed radiation enteropathy. Histological examination indicated that VE-cadherin-Cre; p53FL/FL mice that developed delayed radiation enteropathy had severe vascular injury in the small intestine, which was manifested by hemorrhage, loss of microvessels and tissue hypoxia. In addition, using dual-energy CT imaging, we showed that VE-cadherin-Cre; p53FL/FL mice had a significant increase in vascular permeability of the small intestine in vivo 28 days after TAI. Together, these findings demonstrate that while sensitization of endothelial cells to radiation does not exacerbate the acute GI radiation syndrome, it is sufficient to promote the development of late radiation enteropathy.