Journal Article

IVIS, Xenogen, Xen20

C5a peptidase, also called SCPA (surface-bound C5a peptidase), is a surface-bound protein on group A streptococci (GAS), etiologic agents for a variety of human diseases including pharyngitis, impetigo, toxic shock, and necrotizing fasciitis, as well as the postinfection sequelae rheumatic fever and rheumatic heart disease. This protein is highly conserved among different serotypes and is also expressed in human isolates of group B, C, and G streptococci. Human tonsils are the primary reservoirs for GAS, maintaining endemic disease across the globe. We recently reported that GAS preferentially target nasal mucosa-associated lymphoid tissue (NALT) in mice, a tissue functionally analogous to human tonsils. Experiments using a C5a peptidase loss-of-function mutant and an intranasal infection model showed that this protease is required for efficient colonization of NALT. An effective vaccine should prevent infection of this secondary lymphoid tissue; therefore, the potential of anti-SCPA antibodies to protect against streptococcal infection of NALT was investigated. Experiments showed that GAS colonization of NALT was significantly reduced following intranasal immunization of mice with recombinant SCPA protein administered alone or with cholera toxin, whereas a high degree of GAS colonization of NALT was observed in control mice immunized with phosphate-buffered saline only. Moreover, administration of anti-SCPA serum by the intranasal route protected mice against streptococcal infection. These results suggest that intranasal immunization with SCPA would prevent colonization and infection of human tonsils, thereby eliminating potential reservoirs that maintain endemic disease.

Journal Article

Animals, Blotting, Western, Xen26, Cell Line, Tumor, Diagnostic Imaging/methods, Gene Therapy/*methods, Genetic Engineering/*methods, Genetic Vectors/*therapeutic use, Humans, Male, Mice, Mice, Inbred BALB C, Neoplasms/*therapy, Perforin/*genetics/therapeutic use, Promoter Regions, Genetic, Salmonella typhimurium/*genetics, bcl-Associated Death Protein/genetics IVIS, Xenogen

Tumor-targeting bacteria have been studied in terms of their ability to visualize the infection pathway (through imaging probes) or to carry therapeutic molecules to tumors. To integrate these monitoring and therapeutic functions, we engineered attenuated Salmonella typhimurium defective in guanosine 5'-diphosphate-3'-diphosphate synthesis to carry cytotoxic proteins (cytolysin A) and express reporter genes. We successfully visualized the therapeutic process with these engineered bacteria in mice and found that they often mediated complete tumor (CT-26) eradication on cytotoxic gene induction. Furthermore, treatment with the engineered bacteria markedly suppressed metastatic tumor growth.

Journal Article

Animals, Bone Marrow Cells/metabolism/microbiology, Gene Expression Regulation, Intestines/metabolism, Kinetics, Lectins/chemistry, Listeria Infections/*metabolism/*prevention & control, Listeria monocytogenes/*metabolism, Mice, Mice, Inbred C57BL, Mice, Transgenic, Myeloid Differentiation Factor 88/metabolism/*physiology, Proteins/*metabolism, Recombinant Proteins/metabolism, Toll-Like Receptors/metabolism IVIS, Xenogen, Xen32

Listeria monocytogenes is a food-borne bacterial pathogen that causes systemic infection by traversing the intestinal mucosa. Although MyD88-mediated signals are essential for defense against systemic L. monocytogenes infection, the role of Toll-like receptor and MyD88 signaling in intestinal immunity against this pathogen has not been defined. We show that clearance of L. monocytogenes from the lumen of the distal small intestine is impaired in MyD88(-/-) mice. The distal ileum of wild-type (wt) mice expresses high levels of RegIII gamma, which is a bactericidal lectin that is secreted into the bowel lumen, whereas RegIII gamma expression in MyD88(-/-) mice is nearly undetectable. In vivo depletion of RegIII gamma from the small intestine of wt mice diminishes killing of luminal L. monocytogenes, whereas reconstitution of MyD88-deficient mice with recombinant RegIII gamma enhances intestinal bacterial clearance. Experiments with bone marrow chimeric mice reveal that MyD88-mediated signals in nonhematopoietic cells induce RegIII gamma expression in the small intestine, thereby enhancing bacterial killing. Our findings support a model of MyD88-mediated epithelial conditioning that protects the intestinal mucosa against bacterial invasion by inducing RegIII gamma.

Journal Article

IVIS, B16-F10-luc-G5, B16F10-luc-G5, B16-F10-luc, B16F10-luc, Animals; Base Sequence; Cell Line, Tumor; Collagen/*chemistry; DNA Primers; *Gene Silencing; Mice; RNA, Small Interfering/*administration & dosage/*chemistry; Reverse Transcriptase Polymerase Chain Reaction

Silencing gene expression by small interfering RNAs (siRNAs) has become a powerful tool for the genetic analysis of many animals. However, the rapid degradation of siRNA and the limited duration of its action in vivo have called for an efficient delivery technology. Here, we describe that siRNA complexed with a synthetic collagen poly(Pro-Hyp-Gly) (SYCOL) is resistant to nucleases and is efficiently transferred into cells in vitro and in vivo, thereby allowing long-term gene silencing in vivo. We found that the SYCOL-mediated local application of siRNA targeting myostatin, coding a negative regulator of skeletal muscle growth, in mouse skeletal muscles, caused a marked increase in the muscle mass within a few weeks after application. Furthermore, in vivo administration of an anti-luciferase siRNA/SYCOL complex partially reduced luciferase expression in xenografted tumors in vivo. These results indicate a SYCOL-based non-viral delivery method could be a reliable simple approach to knockdown gene expression by RNAi in vivo as well as in vitro.

Journal Article

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

BACKGROUND: Despite the discovery of novel inhibitors of tumor angiogenesis, protein-based antiangiogenic cancer therapy suffers some limitations that antiangiogenic gene therapy could overcome. We investigated whether intra-tumoral electrotransfer of three angiogenic plasmids could inhibit tumor growth and metastasis. METHODS: Plasmids encoding recombinant disintegrin domain of ADAM-15 (RDD), thrombospondin 1 (TSP-1), and the soluble isoform of the VEGF receptor 1 (sFlt-1) were injected into B16F10 melanoma-bearing C57BL/6 mice followed by electroporation. Tumor volume was measured daily using a digital caliper. Metastasis was monitored by in vivo bioluminescence after surgical removal of the primary luciferase-encoding B16F10 tumor 5 days after intra-tumoral electrotransfer. Markers of vascularization and cell proliferation were quantified by immunohistochemistry. RESULTS: Intra-tumoral electrotransfer of the antiangiogenic plasmids induced a significant inhibition of tumor growth, doubling of mean survival time and long-term survivors ( approximately 40% vs 0% in control). When the tumor was removed by surgery after intra-tumoral plasmid electrotransfer, a significant decrease in tumor metastasis was observed leading to long-term tumor-free survival especially after treatment with pRDD plasmid (84% vs 0% in control). Unlike pTSP-1 and psFlt-1, pRDD significantly decreased cell proliferation in B16F10 primary tumors which express alphavbeta3 and alpha5beta1 integrins. No effect of antiangiogenic plasmid electrotransfer on normal skin blood flow was detected. CONCLUSION: The intra-tumoral electrotransfer of the three antiangiogenic plasmids is a promising method for the treatment of melanoma. The plasmid encoding RDD seems to be particularly effective due to its direct antitumoral activity combined with angiogenesis suppression, and its marked inhibition of metastasis.