Citation Details

Journal Article

AngioSense, Animals; Blood Vessels/embryology/*physiology; Chromosomes, Artificial, Bacterial; Embryo, Mammalian; Endothelial Cells/cytology/metabolism; Endothelium, Vascular/cytology/embryology/metabolism; Female; Founder Effect; Gene Expression Regulation, Developmental; Genes, Reporter; Mice; *Mice, Transgenic; Microscopy, Fluorescence; Morphogenesis/physiology; *Neovascularization, Pathologic; *Neovascularization, Physiologic; Retina/embryology/*physiology; Vascular Endothelial Growth Factor A/genetics/metabolism; Vascular Endothelial Growth Factor Receptor-1/genetics/*metabolism; Vascular Endothelial Growth Factor Receptor-2/genetics/metabolism

Blood vessel development and network patterning are controlled by several signaling molecules, including VEGF, FGF, TGF-ss, and Ang-1,2. Among these, the role of VEGF-A signaling in vessel morphogenesis is best understood. The biological activity of VEGF-A depends on its reaction with specific receptors Flt1 and Flk1. Roles of VEGF-A signaling in endothelial cell proliferation, migration, survival, vascular permeability, and induction of tip cell filopodia have been reported. In this study, we have generated Flt1-tdsRed BAC transgenic (Tg) mice to monitor Flt1 gene expression during vascular development. We show that tdsRed fluorescence is observed within blood vessels of adult mice and embryos, indicative of retinal angiogenesis and tumor angiogenesis. Flt1 expression recapitulated by Flt1-tdsRed BAC Tg mice overlapped well with Flk1, while Flt1 was expressed more abundantly in endothelial cells of large blood vessels such as dorsal aorta and presumptive stalk cells in retina, providing a unique model to study blood vessel development.

Journal Article

AngioSense, Animals; Antigens, CD/metabolism; Antigens, Differentiation, Myelomonocytic/metabolism; Calcium-Binding Proteins/metabolism; Central Nervous System/metabolism; Green Fluorescent Proteins/genetics/*metabolism; Immunohistochemistry/*methods; Lipopolysaccharides/pharmacology; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microfilament Proteins/metabolism; Microglia/cytology/drug effects/*metabolism; Microscopy, Confocal/*methods; Receptors, Cytokine/genetics/metabolism; Receptors, HIV/genetics/metabolism; Reproducibility of Results

Microglia are specialized immune cells of the brain. Upon insult, microglia initiate a cascade of cellular responses including a characteristic change in cell morphology. To study the dynamics of microglia immune response in situ, we developed an automated image analysis method that enables the quantitative assessment of microglia activation state within tissue based solely on cell morphology. Per cell morphometric analysis of fluorescently labeled microglia is achieved through local iterative threshold segmentation, which reduces errors caused by signal-to-noise variation across large volumes. We demonstrate, utilizing systemic application of lipopolysaccharide as a model of immune challenge, that several morphological parameters, including cell perimeter length, cell roundness and soma size, quantitatively distinguish resting versus activated populations of microglia within tissue comparable to traditional immunohistochemistry methods. Furthermore, we provide proof-of-concept data that monitoring soma size enables the longitudinal assessment of microglia activation in the mouse neocortex imaged via 2-photon in vivo microscopy. The ability to quantify microglia activation automatically by shape alone allows unbiased and rapid analysis of both fixed and in vivo central nervous system tissue.

Journal Article

AngioSense, Annexin Vivo, Annexin-Vivo, Aniline Compounds/*pharmacology; Animals; Antineoplastic Agents/*pharmacology; *Apoptosis; Breast Neoplasms/drug therapy/*physiopathology; Cell Line, Tumor; Female; Green Fluorescent Proteins; Humans; Image Processing, Computer-Assisted; Mice; Mice, Nude; Mitochondrial Membranes/drug effects/*physiology; Mitochondrial Proteins/metabolism; Molecular Imaging/*methods; Pancreatic Neoplasms/drug therapy/*physiopathology; Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors; Recombinant Fusion Proteins/metabolism; Single-Cell Analysis; Sulfonamides/*pharmacology; Tumor Microenvironment

Observing drug responses in the tumor microenvironment in vivo can be technically challenging. As a result, cellular responses to molecularly targeted cancer drugs are often studied in cell culture, which does not accurately represent the behavior of cancer cells growing in vivo. Using high-resolution microscopy and fluorescently labeled genetic reporters for apoptosis, we developed an approach to visualize drug-induced cell death at single-cell resolution in vivo. Stable expression of the mitochondrial intermembrane protein IMS-RP was established in human breast and pancreatic cancer cells. Image analysis was then used to quantify release of IMS-RP into the cytoplasm upon apoptosis and irreversible mitochondrial permeabilization. Both breast and pancreatic cancer cells showed higher basal apoptotic rates in vivo than in culture. To study drug-induced apoptosis, we exposed tumor cells to navitoclax (ABT-263), an inhibitor of Bcl-2, Bcl-xL, and Bcl-w, both in vitro and in vivo. Although the tumors responded to Bcl-2 inhibition in vivo, inducing apoptosis in around 20% of cancer cells, the observed response was much higher in cell culture. Together, our findings show an imaging technique that can be used to directly visualize cell death within the tumor microenvironment in response to drug treatment.

Journal Article

AngioSense, Abdomen; Animals; Imaging, Three-Dimensional; Liver/cytology; Mice; Mice, Transgenic; Microscopy/*instrumentation/*methods; Molecular Imaging/*instrumentation/*methods; Pancreas/cytology/ultrastructure; Time-Lapse Imaging

Intravital imaging of brain and bone marrow cells in the skull with subcellular resolution has revolutionized neurobiology, immunology and hematology. However, the application of this powerful technology in studies of abdominal organs has long been impeded by organ motion caused by breathing and heartbeat. Here we describe for the first time a simple device designated 'microstage' that effectively reduces organ motions without causing tissue lesions. Combining this microstage device with an upright intravital laser scanning microscope equipped with a unique stick-type objective lens, the system enables subcellular-level imaging of abdominal organs in live mice. We demonstrate that this technique allows for the quantitative analysis of subcellular structures and gene expressions in cells, the tracking of intracellular processes in real-time as well as three-dimensional image construction in the pancreas and liver of the live mouse. As the aforementioned analyses based on subcellular imaging could be extended to other intraperitoneal organs, the technique should offer great potential for investigation of physiological and disease-specific events of abdominal organs. The microstage approach adds an exciting new technique to the in vivo imaging toolbox.

Journal Article

ProSense, IVIS, Animals; Breast Neoplasms/pathology/*surgery; Cell Line, Tumor; Disease Models, Animal; Female; *Microscopy, Fluorescence; Rats; *Surgery, Computer-Assisted; Transplantation, Isogeneic; Xenograft Model Antitumor Assays

Tumor involvement of resection margins is found in a large proportion of patients who undergo breast-conserving surgery. Near-infrared (NIR) fluorescence imaging is an experimental technique to visualize cancer cells during surgery. To determine the accuracy of real-time NIR fluorescence imaging in obtaining tumor-free resection margins, a protease-activatable NIR fluorescence probe and an intraoperative camera system were used in the EMR86 orthotopic syngeneic breast cancer rat model. Influence of concentration, timing and number of tumor cells were tested in the MCR86 rat breast cancer cell line. These variables were significantly associated with NIR fluorescence probe activation. Dosing and tumor size were also significantly associated with fluorescence intensity in the EMR86 rat model, whereas time of imaging was not. Real-time NIR fluorescence guidance of tumor resection resulted in a complete resection of 17 out of 17 tumors with minimal excision of normal healthy tissue (mean minimum and a mean maximum tumor-free margin of 0.2 +/- 0.2 mm and 1.3 +/- 0.6 mm, respectively). Moreover, the technique enabled identification of remnant tumor tissue in the surgical cavity. Histological analysis revealed that the NIR fluorescence signal was highest at the invasive tumor border and in the stromal compartment of the tumor. In conclusion, NIR fluorescence detection of breast tumor margins was successful in a rat model. This study suggests that clinical introduction of intraoperative NIR fluorescence imaging has the potential to increase the number of complete tumor resections in breast cancer patients undergoing breast-conserving surgery.