Citation Details

Journal Article

splenic monocytes; in vivo imaging; ProSense; FMT; fluorescence molecular tomography

A current paradigm states that monocytes circulate freely and patrol blood vessels but differentiate irreversibly into dendritic cells (DCs) or macrophages upon tissue entry. Here we show that bona fide undifferentiated monocytes reside in the spleen and outnumber their equivalents in circulation. The reservoir monocytes assemble in clusters in the cords of the subcapsular red pulp and are distinct from macrophages and DCs. In response to ischemic myocardial injury, splenic monocytes increase their motility, exit the spleen en masse, accumulate in injured tissue, and participate in wound healing. These observations uncover a role for the spleen as a site for storage and rapid deployment of monocytes and identify splenic monocytes as a resource that the body exploits to regulate inflammation.

Journal Article

Xen41, Xen 41, Pseudomonas aeruginosa Xen41, IVIS

BACKGROUND: : Experimental models of intestinal ischemia-reperfusion (IIR) injury are invariably performed in mice harboring their normal commensal flora, even though multiple IIR events occur in humans during prolonged intensive care confinement when they are colonized by a highly pathogenic hospital flora. The aims of this study were to determine whether the presence of the human pathogen Pseudomonas aeruginosa in the distal intestine potentiates the lethality of mice exposed to IIR and to determine what role any in vivo virulence activation plays in the observed mortality. METHODS: : Seven- to 9-week-old C57/BL6 mice were exposed to 15 minutes of superior mesenteric artery occlusion (SMAO) followed by direct intestinal inoculation of 1.0 x 10 colony-forming unit of P. aeruginosa PAO1 into the ileum and observed for mortality. Reiterative studies were performed in separate groups of mice to evaluate both the migration/dissemination pattern and in vivo virulence activation of intestinally inoculated strains using live photon camera imaging of both a constitutive bioluminescent P. aeruginosa PAO1 derivative XEN41 and an inducible reporter derivative of PAO1, the PAO1/lecA:luxCDABE that conditionally expresses the quorum sensing-dependent epithelial disrupting virulence protein PA 1 Lectin (PA-IL). RESULTS: : Mice exposed to 15 minutes of SMAO and reperfusion with intestinal inoculation of P. aeruginosa had a significantly increased mortality rate (p < 0.001) of 100% compared with <10% for sham-operated mice intestinally inoculated with P. aeruginosa without SMAO and IIR alone (<50%). Migration/dissemination patterns of P. aeruginosa in mice subjected to IIR demonstrated proximal migration of distally injected strains and translocation to mesenteric lymph nodes, liver, spleen, lung, and kidney. A key role for in vivo virulence expression of the barrier disrupting adhesin PA-IL during IIR was established since its expression was enhanced during IR and mutant strains lacking PA-IL displayed attenuated mortality. CONCLUSIONS: : The presence of intestinal P. aeruginosa potentiates the lethal effect of IIR in mice in part due to in vivo virulence activation of its epithelial barrier disrupting protein PA-IL.

Journal Article

Amoxicillin; Animals; Bioware; DNA Transposable Elements; Female; Luminescent Measurements; Lung; Mice; Mice, Inbred BALB C; Nasopharynx; Operon; Promoter Regions, Genetic; pXen-5; Streptococcus pneumoniae; Transformation, Bacterial, Xen10, Xen7

Animal studies with Streptococcus pneumoniae have provided valuable models for drug development. In order to monitor long-term pneumococcal infections noninvasively in living mice, a novel gram-positive lux transposon cassette, Tn4001 luxABCDE Km(r), that allows random integration of lux genes onto the bacterial chromosome was constructed. The cassette was designed so that the luxABCDE and kanamycin resistance genes were linked to form a single promoterless operon. Bioluminescence and kanamycin resistance only occur in a bacterial cell if this operon has transposed downstream of a promoter on the bacterium's chromosome. S. pneumoniae D39 was transformed with plasmid pAUL-A Tn4001 luxABCDE Km(r), and a number of highly bioluminescent colonies were recovered. Genomic DNA from the brightest D39 strain was used to transform a number of clinical S. pneumoniae isolates, and several of these strains were tested in animal models, including a pneumococcal lung infection model. Strong bioluminescent signals were seen in the lungs of the animals containing these pneumococci, allowing the course and antibiotic treatment of the infections to be readily monitored in real time in the living animals. Recovery of the bacteria from the animals showed that the bioluminescent signal corresponded to the number of CFU and that the lux construct was highly stable even after several days in vivo. We believe that this lux transposon will greatly expand the ability to evaluate drug efficacy against gram-positive bacteria in living animals using bioluminescence.

Journal Article

IVIS, B16-F10-luc-G5, B16F10-luc-G5, B16-F10-luc, B16F10-luc,

The therapeutic potential of tocotrienol, a vitamin E extract with anti-cancer properties, is hampered by its failure to specifically reach tumors after intravenous administration. In this work, we demonstrated that novel transferrin-bearing, tocopheryl-based multilamellar vesicles entrapping tocotrienol significantly improved tocotrienol uptake by cancer cells overexpressing transferrin receptors. This led to a dramatically improved therapeutic efficacy in vitro, ranging from 17-fold to 72-fold improvement depending on the cell lines, compared to the free drug. In vivo, the intravenous administration of this novel tocotrienol formulation led to complete tumor eradication for 40% of B16-F10 murine melanoma tumors and 20% of A431 human epidermoid carcinoma tumors. Animal survival was improved by more than 20days compared to controls, for the two tumor models tested. These therapeutic effects, together with the lack of toxicity, potentially make transferrin-bearing vesicles entrapping tocotrienol a highly promising therapeutic system as part as an anti-cancer therapeutic strategy.

Journal Article

in vivo imaging; MMPSense; microRNA 21; glioma

Substantial data indicate that microRNA 21 (miR-21) is significantly elevated in glioblastoma (GBM) and in many other tumors of various origins. This microRNA has been implicated in various aspects of carcinogenesis, including cellular proliferation, apoptosis, and migration. We demonstrate that miR-21 regulates multiple genes associated with glioma cell apoptosis, migration, and invasiveness, including the RECK and TIMP3 genes, which are suppressors of malignancy and inhibitors of matrix metalloproteinases (MMPs). Specific inhibition of miR-21 with antisense oligonucleotides leads to elevated levels of RECK and TIMP3 and therefore reduces MMP activities in vitro and in a human model of gliomas in nude mice. Moreover, downregulation of miR-21 in glioma cells leads to decreases of their migratory and invasion abilities. Our data suggest that miR-21 contributes to glioma malignancy by downregulation of MMP inhibitors, which leads to activation of MMPs, thus promoting invasiveness of cancer cells. Our results also indicate that inhibition of a single oncomir, like miR-21, with specific antisense molecules can provide a novel therapeutic approach for “physiological” modulation of multiple proteins whose expression is deregulated in cancer.