Plant phenolics inhibit focal adhesion kinase and suppress host cell invasion by uropathogenic Escherichia coli

Traditional folk treatments for the prevention and management of urinary tract infections (UTIs) and other infectious diseases often include plants and plant extracts that are rich in phenolic compounds. These have been ascribed a variety of activities, including inhibition of bacterial interactions with host cells. Here, we tested a panel of four well-studied phenolic compounds-caffeic acid phenethyl ester (CAPE), resveratrol, catechin, and epigallocatechin gallate-for the effects on host cell adherence and invasion by uropathogenic Escherichia coli (UPEC). These bacteria, which are the leading cause of UTIs, can bind and subsequently invade bladder epithelial cells via an actin-dependent process. Intracellular UPEC reservoirs within the bladder are often protected from antibiotics and host defenses and likely contribute to the development of chronic and recurrent infections. In cell culture-based assays, only resveratrol had a notable negative effect on UPEC adherence to bladder cells. However, both CAPE and resveratrol significantly inhibited UPEC entry into the host cells, coordinate with attenuated phosphorylation of the host actin regulator Focal Adhesion Kinase (FAK or PTK2) and marked increases in the numbers of focal adhesion structures. We further show that the intravesical delivery of resveratrol inhibits UPEC infiltration of the bladder mucosa in a murine UTI model and that resveratrol and CAPE can disrupt the ability of other invasive pathogens to enter host cells. Together, these results highlight the therapeutic potential of molecules like CAPE and resveratrol, which could be used to augment antibiotic treatments by restricting pathogen access to protective intracellular niches.IMPORTANCEUrinary tract infections (UTIs) are exceptionally common and increasingly difficult to treat due to the ongoing rise and spread of antibiotic-resistant pathogens. Furthermore, the primary cause of UTIs, uropathogenic Escherichia coli (UPEC), can avoid antibiotic exposure and many host defenses by invading the epithelial cells that line the bladder surface. Here, we identified two plant-derived phenolic compounds that disrupt activation of the host machinery needed for UPEC entry into bladder cells. One of these compounds, resveratrol, effectively inhibited UPEC invasion of the bladder mucosa in a mouse UTI model, and both phenolic compounds significantly reduced host cell entry by other invasive pathogens. These findings suggest that select phenolic compounds could be used to supplement existing antibacterial therapeutics by denying uropathogens shelter within host cells and tissues and help explain some of the benefits attributed to traditional plant-based medicines.

Plant Phenolics Inhibit Focal Adhesion Kinase and Suppress Host Cell Invasion by Uropathogenic Escherichia coli

Traditional folk treatments for the prevention and management of urinary tract infections (UTIs) and other infectious diseases often include plants and plant extracts that are rich in phenolic and polyphenolic compounds. These have been ascribed a variety of activities, including inhibition of bacterial interactions with host cells. Here we tested a panel of four well-studied phenolic compounds - caffeic acid phenethyl ester (CAPE), resveratrol, catechin, and epigallocatechin gallate - for effects on host cell adherence and invasion by uropathogenic Escherichia coli (UPEC). These bacteria, which are the leading cause of UTIs, can bind and subsequently invade bladder epithelial cells via an actin-dependent process. Intracellular UPEC reservoirs within the bladder are often protected from antibiotics and host defenses, and likely contribute to the development of chronic and recurrent infections. Using cell culture-based assays, we found that only resveratrol had a notable negative effect on UPEC adherence to bladder cells. However, both CAPE and resveratrol significantly inhibited UPEC entry into the host cells, coordinate with attenuated phosphorylation of the host actin regulator Focal Adhesion Kinase (FAK, or PTK2) and marked increases in the numbers of focal adhesion structures. We further show that the intravesical delivery of resveratrol inhibits UPEC infiltration of the bladder mucosa in a murine UTI model, and that resveratrol and CAPE can disrupt the ability of other invasive pathogens to enter host cells. Together, these results highlight the therapeutic potential of molecules like CAPE and resveratrol, which could be used to augment antibiotic treatments by restricting pathogen access to protective intracellular niches.

E. coli Common pili promote the fitness and virulence of a hybrid aEPEC/ExPEC strain within diverse host environments

Pathogenic subsets of Escherichia coli include diarrheagenic (DEC) strains that cause disease within the gut and extraintestinal pathogenic E. coli (ExPEC) strains that are linked with urinary tract infections, bacteremia, and other infections outside of intestinal tract. Among DEC strains is an emergent pathotype known as atypical enteropathogenic E. coli (aEPEC), which can cause severe diarrhea. Recent sequencing efforts revealed that some E. coli strains possess genetic features that are characteristic of both DEC and ExPEC isolates. BA1250 is a newly reclassified hybrid strain with characteristics of aEPEC and ExPEC. This strain was isolated from a child with diarrhea, but its genetic features indicate that it might have the capacity to cause disease at extraintestinal sites. The spectrum of adhesins encoded by hybrid strains like BA1250 are expected to be especially important in facilitating colonization of diverse niches. E. coli common pilus (ECP) is an adhesin expressed by many E. coli pathogens, but how it impacts hybrid strains has not been ascertained. Here, using zebrafish larvae as surrogate hosts to model both gut colonization and extraintestinal infections, we found that ECP can act as a multi-niche colonization and virulence factor for BA1250. Furthermore, our results indicate that ECP-related changes in activation of envelope stress response pathways may alter the fitness of BA1250. Using an in silico approach, we also delineated the broader repertoire of adhesins that are encoded by BA1250, and provide evidence that the expression of at least a few of these varies in the absence of functional ECP.

Ucl fimbriae regulation and glycan receptor specificity contribute to gut colonisation by extra-intestinal pathogenic Escherichia coli

Extra-intestinal pathogenic Escherichia coli (ExPEC) belong to a critical priority group of antibiotic resistant pathogens. ExPEC establish gut reservoirs that seed infection of the urinary tract and bloodstream, but the mechanisms of gut colonisation remain to be properly understood. Ucl fimbriae are attachment organelles that facilitate ExPEC adherence. Here, we investigated cellular receptors for Ucl fimbriae and Ucl expression to define molecular mechanisms of Ucl-mediated ExPEC colonisation of the gut. We demonstrate differential expression of Ucl fimbriae in ExPEC sequence types associated with disseminated infection. Genome editing of strains from two common sequence types, F11 (ST127) and UTI89 (ST95), identified a single nucleotide polymorphism in the ucl promoter that changes fimbriae expression via activation by the global stress-response regulator OxyR, leading to altered gut colonisation. Structure-function analysis of the Ucl fimbriae tip-adhesin (UclD) identified high-affinity glycan receptor targets, with highest affinity for sialyllacto-N-fucopentose VI, a structure likely to be expressed on the gut epithelium. Comparison of the UclD adhesin to the homologous UcaD tip-adhesin from Proteus mirabilis revealed that although they possess a similar tertiary structure, apart from lacto-N-fucopentose VI that bound to both adhesins at low-micromolar affinity, they recognize different fucose- and glucose-containing oligosaccharides. Competitive surface plasmon resonance analysis together with co-structural investigation of UcaD in complex with monosaccharides revealed a broad-specificity glycan binding pocket shared between UcaD and UclD that could accommodate these interactions. Overall, our study describes a mechanism of adaptation that augments establishment of an ExPEC gut reservoir to seed disseminated infections, providing a pathway for the development of targeted anti-adhesion therapeutics.

ExPEC infection of the urinary tract and bloodstream is frequently seeded from an intestinal reservoir, necessitating an understanding of the mechanisms that promote gut colonisation. Here we employed molecular and structural approaches to define the regulation and function of ExPEC Ucl fimbriae as a gut colonisation factor. We describe how mutations in the non-coding regulatory region of the ucl promoter cause increased Ucl fimbriae expression and promote enhanced gut colonisation via tuned induction by a global regulator that senses oxygen stress. We further define the glycan receptor targets of Ucl fimbriae and characterise the structural features of the Ucl adhesin that facilitate these interactions. These findings explain how ExPEC can adapt to survival in the gut to seed extra-intestinal infection.

The Cdkn2a gene product p19ARF (alternative reading frame) is a critical regulator of IFNβ-mediated Lyme arthritis

Lyme disease is caused by infection with the tick-borne spirochete Borrelia burgdorferi, with a spectrum of clinical disorders. Infected C3H mice develop severe arthritis while B6 mice display mild arthritis, allowing analysis of host genetic contribution to disease. B6 mice introgressed with the C3H allele of Bbaa1 on Chr4, B6.C3-Bbaa1, display increased severity of arthritis, and heightened expression of Type I IFN. IFNβ, was identified as the key effector for arthritis severity, acting through the muscle regulatory protein myostatin. To identify regulators of IFNβ in the Bbaa1 locus, candidate genes were subjected to siRNA silencing in macrophages. The Cdkn2a gene encoded protein p19ARF was identified as the modulator of IFNβ expression. B6 Arf−/− mice reconstituted with cells expressing the C3H allele of p19ARF developed severe arthritis, whereas mice reconstituted with cells expressing the B6 allele developed mild disease. IFNβ induction by p19ARF is inducible by other pathogens and a variety of PAMPs. P19ARF regulation of IFNβ involved the tumor suppressor p53 and transcription repressor BCL6 in myeloid cells. Indeed, targeted blocking of BCL6 enhanced IFNβ activation in the joint tissue of B6 mice and resulted in increased severity of Lyme arthritis. Similar responses in B6 Rag1−/− mice, indicate dependence on myeloid cells expression of BCL6. Thus, we have identified novel involvement of p19ARF in modulating IFNβ expression in Lyme arthritis development.

Supported by R01 AR043521

The Cdkn2a gene product p19 alternative reading frame (p19ARF) is a critical regulator of IFNβ-mediated Lyme arthritis

Type I interferon (IFN) has been identified in patients with Lyme disease, and its abundant expression in joint tissues of C3H mice precedes development of Lyme arthritis. Forward genetics using C3H mice with severe Lyme arthritis and C57BL/6 (B6) mice with mild Lyme arthritis identified the Borrelia burgdorferi arthritis-associated locus 1 (Bbaa1) on chromosome 4 (Chr4) as a regulator of B. burgdorferi-induced IFNβ expression and Lyme arthritis severity. B6 mice introgressed with the C3H allele for Bbaa1 (B6.C3-Bbaa1 mice) displayed increased severity of arthritis, which is initiated by myeloid lineage cells in joints. Using advanced congenic lines, the physical size of the Bbaa1 interval has been reduced to 2 Mbp, allowing for identification of potential genetic regulators. Small interfering RNA (siRNA)-mediated silencing identified Cdkn2a as the gene responsible for Bbaa1 allele-regulated induction of IFNβ and IFN-stimulated genes (ISGs) in bone marrow-derived macrophages (BMDMs). The Cdkn2a-encoded p19 alternative reading frame (p19ARF) protein regulates IFNβ induction in BMDMs as shown by siRNA silencing and overexpression of ARF. In vivo studies demonstrated that p19ARF contributes to joint-specific induction of IFNβ and arthritis severity in B. burgdorferi-infected mice. p19ARF regulates B. burgdorferi-induced IFNβ in BMDMs by stabilizing the tumor suppressor p53 and sequestering the transcriptional repressor BCL6. Our findings link p19ARF regulation of p53 and BCL6 to the severity of IFNβ-induced Lyme arthritis in vivo and indicate potential novel roles for p19ARF, p53, and BCL6 in Lyme disease and other IFN hyperproduction syndromes.

Lyme disease is caused by infection with the tick-transmitted bacterium Borrelia burgdorferi. Although different isolates of B. burgdorferi have distinct potential for dissemination and tissue invasion, factors intrinsic to the infected host also play an important role in directing the severity of Lyme disease. In the animal model, infected C3H mice develop severe Lyme arthritis following elevation of type I IFN in joint tissue, while in C57BL/6 (B6) mice arthritis is mild and not associated with type I IFN. We demonstrated that the Borrelia burgdorferi arthritis-associated locus 1 (Bbaa1) on chromosome 4 (Chr4) intrinsically controls the magnitude of IFNβ production and the severity of Lyme arthritis in C3H vs B6 mice. The Cdkn2a gene was positionally identified as the regulator of IFNβ within Bbaa1, and determined to function through its protein product p19 alternative reading frame (p19ARF). ARF regulates IFNβ expression and Lyme arthritis severity by modulating the activities of the tumor suppressor p53 and transcriptional repressor BCL6. Our study provides new insight and potential therapeutic targets for the investigation of type I IFN-dependent Lyme arthritis and other IFN-driven diseases.

The change of the rate-controlling processes with temperature in the hydration of anhydrous nedocromil sodium by water vapor

A six-stage model is proposed to describe the overall process of sorption of water vapor on and into anhydrous nedocromil sodium. The way in which temperature, pressure, and time affect the rate of reaction for each of the stages has been analyzed. Experimental data for the measured rates, where temperature, pressure, and time are variables, are compared with the predictions obtained from each of the six stages. The most useful comparator is a graphical representation of reduced time versus hydration rate. The theoretical equations presented as a shape analysis of the experimental curves show the process to have different controlling mechanisms in three temperature regions: up to 27 degrees C, hydration is controlled by a nucleation and growth mechanism; between 27 and 31 degrees C, the process is dominated by diffusion of water molecules into the crystal; and >31 degrees C, neither nucleation nor diffusion are controlling but some, as yet, undetermined physical processes.

Microchip technology in drug delivery

The realization that the therapeutic efficacy of certain drugs can be affected dramatically by the way in which they are delivered has created immense interest in controlled drug delivery systems. Much previous work in drug delivery focused on achieving sustained drug release rates over time, while a more recent trend is to make devices that allow the release rate to be varied over time. Advances in microfabrication technology have made an entirely new type of drug delivery device possible. Proof-of-principle experiments have shown that silicon microchips have the ability to store and release multiple chemicals on demand. Future integration of active control electronics, such as microprocessors, remote control units, or biosensors, could lead to the development of a 'pharmacy on a chip,' ie 'smart' microchip implants or tablets that release drugs into the body automatically when needed.

Microchips as Controlled Drug-Delivery Devices

Controlled-release systems are common in a number of product areas, including foods, cosmetics, pesticides, and paper. Microencapsulated systems, for example, are used for the release of flavors and vitamins in foods, fragrances in perfumes, and inks in carbonless copy paper. Controlled-release systems for drug delivery first appeared in the 1960s and 1970s. In the past three decades, the number and variety of controlled release systems for drug-delivery applications has increased dramatically. Many of these use polymers having particular physical or chemical characteristics such as biodegradability, biocompatibility, or responsiveness to pH or temperature changes. However, recent advances in the field of microfabrication have created the possibility of a new class of controlled-release systems for drug delivery, namely, that of small, programmable devices. Their small size, potential for integration with microelectronics, and ability to store and release chemicals on demand could make controlled-release microchips useful in a number of areas, including medical diagnostics, analytical chemistry, chemical detection, industrial process monitoring and control, combinatorial chemistry, microbiology, and fragrance delivery. More importantly, drug-delivery microchips resulting from this convergence of controlled release and microfabrication technologies may provide new treatment options to clinicians in their fight against disease.

Adsorption of water by anhydrous nedocromil sodium from 20 to 40 degrees C

Three different powder preparations of the drug disodium 9-ethyl-4, 6-dioxo-10-propyl-4H,6H pyrano[3,2-g]quinoline-2,8-dicarboxylic trihydrate, Nedocromil sodium (trade name Tilade), have been fully dehydrated in a vacuum and their water vapor adsorption characteristics quantitatively assessed at different water vapor pressures over a temperature range 20 to 40 degrees C. At saturated vapor pressures, 100% RH, rates of adsorption are around 0.1 s(-1/2). Graphs of square root of time against reduced mass during uptake of water vapor at vapor pressures in the range 20 to 47 mm of Hg, all equivalent to 100% RH, indicate control by a diffusion mechanism with activation energies in the range 8 to 24 kJ mol(-1), dependent on the powder preparation method. In two of the powders nonlinear Arrhenius-type plots are interpreted as showing that control of the process is dependent on the surface's ability to hold water molecules at the experimental temperature. The variation in activation energies and the calculated values for diffusivities, around 1 x 10(-13) m(2) s(-1), are used to explore structural involvement in the overall water adsorption process. The measured values of water vapor diffusivity into the structure have been used to predict the water solubility of nedocromil sodium trihydrate, and the results show good agreement to reported solubilities. This approach to solubility prediction is an alternative to the Noyes and Whitney method where ions leaving the surface are monitored.

Complement activation, its consequences, and blockade by gene transfer

The success of xenotransplanting vascularized pig organs into humans is limited owing to the immediate immune reaction, termed hyperacute rejection (HAR). This reaction is primarily mediated by naturally occurring xenoreactive antibodies binding to the graft and activating the complement system, resulting in organ dysfunction. Pig membrane-bound complement regulatory proteins efficiently control autologous complement only and are unable to protect against human complement-mediated damage. One line of current research to overcome HAR of pig organs involves the expression of human complement regulatory proteins by pig cells. In vitro data have demonstrated that pig endothelial cells expressing human regulators of complement activation (RCAs) are resistant to human complement-mediated attack, which has led to the successful production of pigs transgenic for human RCAs. Ex vivo perfusion studies using fresh human blood with organs from these animals has shown an improvement in graft function and survival through expression of human RCAs compared to that of nontransgenic pig organs. Similar results have been observed in primate models, where expression of human RCA proteins on the pig donor organ has resulted in protection against HAR and prolongation of graft survival. The initial complement-mediated immunologic barrier of HAR has been overcome through this genetic incorporation of human RCAs into pigs, and it is now possible to study the subsequent mechanisms of xenograft rejection in the pig-to-human combination.

Atrial natriuretic peptide inhibits the release of endothelium-derived relaxing factor from blood vessels of the rabbit

We investigated the effects of atrial natriuretic peptide (ANP) on release of endothelium-derived relaxing factor (EDRF) from rabbit aorta and central ear artery using inhibition of platelet aggregation and vascular smooth muscle relaxation respectively as measures of EDRF activity. ANP at concentrations greater than 10(-9) M inhibited carbachol-induced EDRF release from rabbit aorta and acetylcholine-induced EDRF release from the central ear artery. These findings are consistent with previous observations that 8-bromo cyclic GMP inhibits EDRF release from rabbit aorta and ANP inhibits release of EDRF from cultured endothelial cells.

Automatic collector of expired 14CO2 for liquid scintillation counting

A filtration technique was employed to trap 14CO2 continuously for liquid scintillation counting. Devices for delivering scintillator and ethanolamine solutions were combined symmetrically with two fritted-glass aspirators for alternating operation. The collector was regulated by a fraction collector timer. Trial and animal tests indicated that the described method was efficient, reliable, and more convenient for frequent collection over long periods than alternative methods. The automatic collector was used for metabolic studies of [1-14C] arachidonic acid in rats kept in metabolic cages and the results were processed by multicompartmental analysis.

The binding of Met-tRNAf to isolated 40-S ribosomal subunits and the formation of Met-tRNAf - 80-S-ribosome initiation complexes

Different forms of 40-S ribosomal subunit, distinguishable by their buoyant densities on CsCl equilibrium density gradients, are formed when derived 40-S ribosomal subunits are incubated with partially purified reticulocyte ribosomal wash proteins. One of these subunits, the 1.37-g-cm-3 form is not present in the cell but the other two forms, the 1.40-g-cm-3 and 1.40-g-cm-3 subunits, are present in cell extracts. 35S label is bound to 1.37-g-cm-3 and 1.40-g-cm-s subunits when [35S]Met-tRANf, GTP and poly(A,U,G) are included in the incubations. The 35S-labelled 40-S subunits recovered, and the amount of 35S label bound to them, are changed if the [35S]Met-tRNAf-40-S-subunit-poly(A,U,G) complexes are first purified on sucrose gradients before analysing them on CsCl. The 1.37-g-cm-3 particle is no longer seen and the total quantity of 35S label on the 40-S subunits is 90% lower after sucrose gradient purification. Between 30% and 40% of the 40-S subunits bind [35S]Met-tRNAf when 1 mM GTP, an excess of ribosomal wash proteins and [35S]Met-tRNAf over derived 40-S subunits, and poly(A,U,G) or AUG is included in the incubations. The omission of poly(A,U,G) or AUG from the incubations substantially lowers the amount of subunit-bound 35S label ultimately recovered. With these incubations less than 10% of the 40-S subunits have bound [35S]Met-tRNAf. [35S]Met-tRNAf binding is affected by the nature of the RNA added. The addition of poly(U), rRNA and native 9-S golbin mRNA is without effect, whereas denatured globin mRNA is stimulatory. Maximum binding is obtained however with AUG. Poly(A,U,G) is less stimulatory than AUG but more stimulatory than denatured mRNA, suggesting that the number as well the accessibility of the AUG initiations condons determines the amount of 35S label bound. Similar results are obtained for the ribosomal-wash-dependent binding of [35S]Met-tRNAf to 80-S ribosomes. Contrary to the binding results, the ability of mRNA to stimulate protein synthesis is dependent on the integrity of the mRNA. Thus, native 9-S globin mRNA but not poly(A,U,G) stimulatex protein synthesis in the wheat germ system. HCHO-treated globin mRNA, although stimulatory, is 45% less effective than native mRNA. The addition of AUG, derived 60-S subunits and extra ribosomal wash is required for the formation of [35S]Met-tRNAf-80-S-ribosome complexes from sucrose-gradient-purified [35S]Met-tRNAf-40-S-subunit complexes. The 80-S ribosome complexes are able to form peptide bonds. Thus, if puromycin is added to the full incubations at zero time, no 35S label is present on the 80-S ribosome. 35S label is released as methionyl-puromycin. If the [35S]Met-tRNAf-40-S-subunit complexes are assembled with poly(A,U,G) or AUG in the incubations and then purified, only derived 60-S subunits are required to form [35S]Met-tRNAf-80-S-ribosome complexes. 35S label is not released from them when puromycin is added to the incubations unless extra ribosomal wash is also added.