Citation Details

Journal Article

Xen8.1, Xen 8.1, S. aureus, IVIS, bioluminescence imaging, Analysis of Variance; Animals; Extracellular Space/*metabolism; Genetic Vectors/genetics; Green Fluorescent Proteins/metabolism; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Confocal; Microscopy, Electron, Transmission; Microscopy, Fluorescence; Movement/*physiology; Neutrophils/*immunology/metabolism/physiology; Opsonin Proteins/metabolism; Skin Diseases, Bacterial/*immunology/metabolism; Toll-Like Receptor 2/metabolism

Neutrophil extracellular traps (NETs) are released as neutrophils die in vitro in a process requiring hours, leaving a temporal gap that invasive microbes may exploit. Neutrophils capable of migration and phagocytosis while undergoing NETosis have not been documented. During Gram-positive skin infections, we directly visualized live polymorphonuclear cells (PMNs) in vivo rapidly releasing NETs, which prevented systemic bacterial dissemination. NETosis occurred during crawling, thereby casting large areas of NETs. NET-releasing PMNs developed diffuse decondensed nuclei, ultimately becoming devoid of DNA. Cells with abnormal nuclei showed unusual crawling behavior highlighted by erratic pseudopods and hyperpolarization consistent with the nucleus being a fulcrum for crawling. A requirement for both Toll-like receptor 2 and complement-mediated opsonization tightly regulated NET release. Additionally, live human PMNs injected into mouse skin developed decondensed nuclei and formed NETS in vivo, and intact anuclear neutrophils were abundant in Gram-positive human abscesses. Therefore early in infection NETosis involves neutrophils that do not undergo lysis and retain the ability to multitask.

Journal Article

OsteoSense, Animals; Bone Remodeling; Disease Models, Animal; Equipment Design; Female; Fluorescence; Head and Neck Neoplasms/pathology/radiography; Image Processing, Computer-Assisted/*methods; Lung Neoplasms/pathology/radiography; Mammary Neoplasms, Experimental/pathology/radiography; Mice; Osteogenesis Imperfecta/pathology/radiography; Tomography, Optical/*methods; Tomography, X-Ray Computed/*methods

The development of hybrid optical tomography methods to improve imaging performance has been suggested over a decade ago and has been experimentally demonstrated in animals and humans. Here we examined in vivo performance of a camera-based hybrid fluorescence molecular tomography (FMT) system for 360 degrees imaging combined with X-ray computed tomography (XCT). Offering an accurately co-registered, information-rich hybrid data set, FMT-XCT has new imaging possibilities compared to stand-alone FMT and XCT. We applied FMT-XCT to a subcutaneous 4T1 tumor mouse model, an Aga2 osteogenesis imperfecta model and a Kras lung cancer mouse model, using XCT information during FMT inversion. We validated in vivo imaging results against post-mortem planar fluorescence images of cryoslices and histology data. Besides offering concurrent anatomical and functional information, FMT-XCT resulted in the most accurate FMT performance to date. These findings indicate that addition of FMT optics into the XCT gantry may be a potent upgrade for small-animal XCT systems.

Journal Article

Animals; Arthritis, Experimental; Bioware; Chemotaxis, Leukocyte; Humans; Inflammation; Mice; Mice, Transgenic; Neutrophils; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Phosphatidylinositol Phosphates; Protein Transport; PTEN Phosphohydrolase; Xen29

Neutrophils encounter and 'prioritize' many chemoattractants in their pursuit of bacteria. Here we tested the possibility that the phosphatase PTEN is responsible for the prioritization of chemoattractants. Neutrophils induced chemotaxis by two separate pathways, the phosphatidylinositol-3-OH kinase (PI(3)K) phosphatase and tensin homolog (PTEN) pathway, and the p38 mitogen-activated protein kinase pathway, with the p38 pathway dominating over the PI(3)K pathway. Pten(-/-) neutrophils could not prioritize chemoattractants and were 'distracted' by chemokines when moving toward bacterial chemoattractants. In opposing gradients, PTEN became distributed throughout the cell circumference, which inhibited all PI(3)K activity, thus permitting 'preferential' migration toward bacterial products via phospholipase A(2) and p38. Such prioritization was defective in Pten(-/-) neutrophils, which resulted in defective bacterial clearance in vivo. Our data identify a PTEN-dependent mechanism in neutrophils to prioritize, 'triage' and integrate responses to multiple chemotactic cues.

Journal Article

near-infrared; near infrared; matrix metalloproteinase; MMP; in vivo imaging; near-infrared fluorescence imaging

A number of different matrix metalloproteinase (MMP) inhibitors have been developed as cytostatic and anti-angiogenic agents and are currently in clinical testing. One major hurdle in assessing the efficacy of such drugs has been the inability to sense or image anti-proteinase activity directly and non-invasively in vivo. We show here that novel, biocompatible near-infrared fluorogenic MMP substrates can be used as activatable reporter probes to sense MMP activity in intact tumors in nude mice. Moreover, we show for the first time that the effect of MMP inhibition can be directly imaged using this approach within hours after initiation of treatment using the potent MMP inhibitor, prinomastat (AG3340). The developed probes, together with novel near-infrared fluorescence imaging technology will enable the detailed analysis of a number of proteinases critical for advancing the therapeutic use of clinical proteinase inhibitors.

Journal Article

in vivo imaging; fluorescence imaging, molecular imaging, MRI, myocardium, SPECT; MMPSense

Molecular imaging agents can be targeted to a specific receptor or protein on the cardiomyocyte surface, or to enzymes released into the interstitial space, such as cathepsins, matrix metalloproteinases and myeloperoxidase. Molecular imaging of the myocardium, however, requires the imaging agent to be small, sensitive (nanomolar levels or better), and able to gain access to the interstitial space. Several novel agents that fulfill these criteria have been used for targeted molecular imaging applications in the myocardium. Magnetic resonance, fluorescence, and single-photon emission CT have been used to image the molecular signals generated by these agents. The use of targeted imaging agents in the myocardium has the potential to provide valuable insights into the pathophysiology of myocardial injury and to facilitate the development of novel therapeutic strategies.