Citation Details

Journal Article

LnCaP-luc2, Prostate Cancer, IVIS, *Gene Silencing; *Gold; Metal Nanoparticles/*chemistry/ultrastructure; Microscopy, Electron, Transmission; Polylysine/chemistry; RNA, Small Interfering/*genetics

Small interfering RNA (siRNA) has been widely proposed to treat various diseases by silencing genes, but its delivery remains a challenge. A well controlled assembly approach is applied to prepare a protease-assisted nanodelivery system. Protease-degradable poly-L-lysine (PLL) and siRNA are fabricated onto gold nanoparticles (AuNPs), by alternating the charged polyelectrolytes. In this study, up to 4 layers of PLL and 3 layers of siRNA (sR3P) are coated. Due to the slow degradation of PLL, the incorporated siRNA is released gradually and shows extended gene-silencing effects. Importantly, the inhibition effect in cells is found to correlate with the number of siRNA layers.

Journal Article

Xen26, Xen 26, Salmonella typhumurium, Animals; Anti-Bacterial Agents/therapeutic use; Cell Separation; Disease Models, Animal; Flow Cytometry; Fluoroquinolones/therapeutic use; Intestine, Small/microbiology; Lymph Nodes/*microbiology; Mesentery/immunology/microbiology; Mice; Mice, Inbred C57BL; Monocytes/immunology/*microbiology; Recurrence; Salmonella Infections, Animal/immunology/*microbiology/pathology; Salmonella typhi/immunology

Enteric pathogens can cause relapsing infections in a proportion of treated patients, but greater understanding of this phenomenon is hindered by the lack of appropriate animal models. We report here a robust animal model of relapsing primary typhoid that initiates after apparently successful antibiotic treatment of susceptible mice. Four days of enrofloxacin treatment were sufficient to reduce bacterial loads below detectable levels in all major organs, and mice appeared otherwise healthy. However, any interruption of further antibiotic therapy allowed renewed fecal shedding and renewed bacterial growth in systemic tissues to occur, and mice eventually succumbed to relapsing infection. In vivo imaging of luminescent Salmonella identified the mesenteric lymph nodes (MLNs) as a major reservoir of relapsing infection. A magnetic-bead enrichment strategy isolated MLN-resident CD11b(+) Gr-1(-) monocytes associated with low numbers of persistent Salmonella. However, the removal of MLNs increased the severity of typhoid relapse, demonstrating that this organ serves as a protective filter to restrain the dissemination of bacteria during antibiotic therapy. Together, these data describe a robust animal model of typhoid relapse and identify an important intestinal phagocyte subset involved in protection against the systemic spread of enteric infection.

Journal Article

Xen14, Xen 14, E. coli Xen14, IVIS, Horse, bioluminescence

Uterine and placental infections are the leading cause of abortion, stillbirth, and preterm delivery in the mare. Whereas uterine and placental infections in women have been studied extensively, a comprehensive examination of the pathogenic processes leading to this unsatisfactory pregnancy outcome in the mare has yet to be completed. Most information in the literature relating to late-term pregnancy loss in mares is based on retrospective studies of clinical cases submitted for necropsy. Here we report the development and application of a novel approach, whereby transgenically modified bacteria transformed with lux genes of Xenorhabdus luminescens or Photorhabdus luminescens origin and biophotonic imaging are utilized to better understand pathogen-induced preterm birth in late-term pregnant mares. This technology uses highly sensitive bioluminescence imaging camera systems to localize and monitor pathogen progression during tissue invasion by measuring the bioluminescent signatures emitted by the lux-modified pathogens. This method has an important advantage in that it allows for the potential tracking of pathogens in vivo in real time and over time, which was hitherto impossible. Although the application of this technology in domestic animals is in its infancy, investigators were successful in identifying the fetal lungs, sinuses, nares, urinary, and gastrointestinal systems as primary tissues for pathogen invasion after experimental infection of pregnant mares with lux-modified Escherichia coli. It is important that pathogens were not detected in other vital organs, such as the liver, brain, and cardiac system. Such precision in localizing sites of pathogen invasion provides potential application for this novel approach in the development of more targeted therapeutic interventions for pathogen-related diseases in the equine and other domestic species.

Journal Article

IntegriSense, Animals; Colorectal Neoplasms/*metabolism/*secondary; Disease Models, Animal; Image Processing, Computer-Assisted; Integrin alphaVbeta3/*metabolism; Intraoperative Period; Liver Neoplasms/*pathology; Male; Neoplasm Transplantation; Rats; Spectroscopy, Near-Infrared/*methods; Tumor Cells, Cultured

AIM: Near-infrared (NIR) fluorescence optical imaging is a promising technique to assess the extent of colorectal metastases during curative-intended surgery. However, NIR fluorescence imaging of liver metastases is highly challenging due to hepatic uptake and clearance of many fluorescent dyes. In the current study, the biodistribution and the ability to demarcate liver and peritoneal metastases were assessed during surgery in a syngeneic rat model of colorectal cancer using an integrin alpha(v)beta(3)-directed NIR fluorescence probe. METHODS: Liver tumors and peritoneal metastases were induced in 7 male WAG/Rij rats by subcapsular inoculation of 0.5 x 10(6) CC531 colorectal cancer rat cells into three distinct liver lobes. Intraoperative and ex vivo fluorescence measurements were performed 24 (N = 3 rats, 7 tumors) and 48 h (N = 4 rats, 9 tumors) after intravenous administration of the integrin alpha(v)beta(3)-directed NIR fluorescence probe. RESULTS: Colorectal metastases had a minimal two-fold higher NIR fluorescence signal than healthy liver tissue and other abdominal organs (p < 0.001). The tumor-to-background ratio was independent of time of imaging (24 h vs. 48 h post-injection; p = 0.31), which facilitates flexible operation planning in future clinical applications. Total fluorescence intensity was significantly correlated with the size of metastases (R(2) = 0.92 for the 24 h group, R(2) = 0.96 for the 48 h group). CONCLUSION: These results demonstrate that colorectal intra-abdominal metastases can be clearly demarcated during surgery using an integrin alpha(v)beta(3) targeting NIR fluorescence probe. Translating these findings to the clinic will have an excellent potential to substantially improve the quality of cancer surgery.

Journal Article

brca1; Cancer; In vivo imaging (VisEn); IVIS Spectrum imaging system; mice; siRNA; vivotag-750

Inhibition of the DNA repair enzyme poly(ADP-ribose) polymerase 1 (PARP1) with small molecules has been shown to be an effective treatment for ovarian cancer with BRCA mutations. Here, we report the in vivo administration of siRNA to Parp1 in mouse models of ovarian cancer. A unique member of the lipid-like materials known as lipidoids is shown to deliver siRNA to disseminated murine ovarian carcinoma allograft tumors following intraperitoneal (i.p.) injection. siParp1 inhibits cell growth, primarily by induction of apoptosis, in Brca1-deficient cells both in vitro and in vivo. Additionally, the treatment extends the survival of mice bearing tumors derived from Brca1-deficient ovarian cancer cells but not from Brca1 wild-type cells, confirming the proposed mechanism of synthetic lethality. Because there are 17 members of the Parp family, the inherent complementarity of RNA affords a high level of specificity for therapeutically addressing Parp1 in the context of impaired homologous recombination.