Citation Details

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

Xen5, Xen 5, Pseudomonas aeruginosa Xen 5, Anti-Bacterial Agents/administration & dosage/*pharmacology/therapeutic; use; Antimicrobial Cationic Peptides/chemistry; Biofilms/drug effects; Cholic Acid/chemistry; Cystic Fibrosis/microbiology; Hemolysis/drug effects; Humans; *Poloxamer; Pseudomonas Infections/drug therapy; Pseudomonas aeruginosa/drug effects/growth & development; Skin Diseases, Bacterial/drug therapy; Staphylococcus aureus/drug effects; Steroids/administration & dosage/*pharmacology/therapeutic use; *Surface-Active Agents

AIMS: Ceragenin CSA-13 is a synthetic mimic of cationic antibacterial peptides, with facial amphiphilic morphology reproduced using a cholic acid scaffold. Previous data have shown that this molecule displays broad-spectrum antibacterial activity, which decreases in the presence of blood plasma. However, at higher concentrations, CSA-13 can cause lysis of erythrocytes. This study was designed to assess in vitro antibacterial and haemolytic activity of CSA-13 in the presence of pluronic F-127. METHODS AND RESULTS: CSA-13 bactericidal activity against clinical strains of bacteria associated with topical infections and in an experimental setting relevant to their pathophysiological environment, such as various epithelial tissue fluids and the airway sputum of patients suffering from cystic fibrosis (CF), was evaluated using minimum inhibitory and minimum bactericidal concentration (MIC/MBC) measurements and bacterial killing assays. We found that in the presence of pluronic F-127, CSA-13 antibacterial activity was only slightly decreased, but CSA-13 haemolytic activity was significantly inhibited. CSA-13 exhibits bacterial killing activity against clinical isolates of Staphylococcus aureus, including methicillin-resistant strains, Pseudomonas aeruginosa present in CF sputa, and biofilms formed by different Gram (+) and Gram (-) bacteria. CSA-13 bactericidal action is partially compromised in the presence of plasma, but is maintained in ascites, cerebrospinal fluid, saliva, and bronchoalveolar lavage fluid. The synergistic action of CSA-13, determined by the use of a standard checkerboard assay, reveals an increase in CSA-13 antibacterial activity in the presence of host defence molecules such as the cathelicidin LL-37 peptide, lysozyme, lactoferrin and secretory phospholipase A (sPLA). CONCLUSION: These results suggest that CSA-13 may be useful to prevent and treat topical infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Combined application of CSA-13 with pluronic F-127 may be beneficial by reducing CSA-13 toxicity.

Journal Article

Xen29, Xen 29, Staphylococcus aureus Xen29, IVISBacterial Physiological Phenomena/drug effects; Bacterial Proteins/genetics/metabolism; Biofilms/*drug effects; *Down-Regulation/drug effects; Fungi/drug effects/physiology; Kingella kingae/chemistry/genetics/*metabolism; Molecular Sequence Data; Polysaccharides, Bacterial/biosynthesis/chemistry/*pharmacology

Cell-free extracts prepared from Kingella kingae colony biofilms were found to inhibit biofilm formation by Aggregatibacter actinomycetemcomitans, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Candida albicans, and K. kingae. The extracts evidently inhibited biofilm formation by modifying the physicochemical properties of the cell surface, the biofilm matrix, and the substrate. Chemical and biochemical analyses indicated that the biofilm inhibition activity in the K. kingae extract was due to polysaccharide. Structural analyses showed that the extract contained two major polysaccharides. One was a linear polysaccharide with the structure -->6)-alpha-d-GlcNAcp-(1-->5)-beta-d-OclAp-(2-->, which was identical to a capsular polysaccharide produced by Actinobacillus pleuropneumoniae serotype 5. The second was a novel linear polysaccharide, designated PAM galactan, with the structure -->3)-beta-d-Galf-(1-->6)-beta-d-Galf-(1-->. Purified PAM galactan exhibited broad-spectrum biofilm inhibition activity. A cluster of three K. kingae genes encoding UDP-galactopyranose mutase (ugm) and two putative galactofuranosyl transferases was sufficient for the synthesis of PAM galactan in Escherichia coli. PAM galactan is one of a growing number of bacterial polysaccharides that exhibit antibiofilm activity. The biological roles and potential technological applications of these molecules remain unknown.

Journal Article

4T1-luc2, IVIS, Bioluminescence

The vacuolar H+-ATPase (V-ATPase), a multisubunit proton pump, has come into focus as an attractive target in cancer invasion. However little is known about the role of V-ATPase in cell death and especially the underlying mechanisms remain mostly unknown. We used the myxobacterial macrolide archazolid B, a potent inhibitor of the V-ATPase, as an experimental drug as well as a chemical tool to decipher V-ATPase related cell death signaling. We found that archazolid induced apoptosis in highly invasive tumor cells at nanomolar concentrations which was executed by the mitochondrial pathway. Prior to apoptosis induction archazolid lead to the activation of a cellular stress response including activation of the hypoxia-inducible factor-1 alpha (HIF1alpha) and autophagy. Autophagy was induced at low concentrations of archazolid that do not alter pH in lysosomes and was shown by degradation of p62 or fusion of autophagosomes with lysosomes. HIF1alpha was induced due to energy stress shown by a decline of the ATP level and followed by a shut down of energy consuming processes. As silencing HIF1alpha increases apoptosis, the cellular stress response was suggested to be a survival mechanism. We conclude that archazolid leads to energy stress which activates adaptive mechanisms like autophagy mediated by HIF1alpha and finally leads to apoptosis. We propose V-ATPase as a promising drugable target in cancer therapy caught up at the interplay of apoptosis, autophagy and cellular/metabolic stress.

Journal Article

PC-3M-luc-C6, PC-3M-luc, IVIS, Bioware, Prostate cancer, Bioluminescence

Normal epithelial cells regulate the secretion of autocrine and paracrine factors that prevent aberrant growth of neighboring cells, leading to healthy development and normal metabolism. One reason for tumor initiation is considered to be a failure of this homeostatic cell competitive system. Here we identify tumor-suppressive microRNAs (miRNAs) secreted by normal cells as anti-proliferative signal entities. Culture supernatant of normal epithelial prostate PNT-2 cells attenuated proliferation of PC-3M-luc cells, prostate cancer cells. Global analysis of miRNA expression signature revealed that a variety of tumor-suppressive miRNAs are released from PNT-2 cells. Of these miRNAs, secretory miR-143 could induce growth inhibition exclusively in cancer cells in vitro and in vivo. These results suggest that secretory tumor-suppressive miRNAs can act as a death signal in a cell competitive process. This study provides a novel insight into a tumor initiation mechanism.