Effects of autologous stromal cells and cytokines on differentiation of equine bone marrow-derived progenitor cells.

OBJECTIVE To develop an in vitro system for differentiation of equine B cells from bone marrow hematopoietic progenitor cells on the basis of protocols for other species. SAMPLE Bone marrow aspirates aseptically obtained from 12 research horses. PROCEDURES Equine bone marrow CD34 cells were sorted by use of magnetic beads and cultured in medium supplemented with cytokines (recombinant human interleukin-7, equine interleukin-7, stem cell factor, and Fms-like tyrosine kinase-3), murine OP9 stromal cell preconditioned medium, and equine fetal bone marrow mesenchymal stromal cell preconditioned medium.

Localization of Burkholderia cepacia complex bacteria in cystic fibrosis lungs and interactions with Pseudomonas aeruginosa in hypoxic mucus.

The localization of Burkholderia cepacia complex (Bcc) bacteria in cystic fibrosis (CF) lungs, alone or during coinfection with Pseudomonas aeruginosa, is poorly understood. We performed immunohistochemistry for Bcc and P. aeruginosa bacteria on 21 coinfected or singly infected CF lungs obtained at transplantation or autopsy.

A 3-D airway epithelial cell and macrophage co-culture system to study Rhodococcus equi infection.

We developed a 3-D equine bronchial epithelial cell (BEC) culture that fully differentiates into ciliary beating and mucus producing cells. Using this system, we evaluated how mucus affects the phagocytic activity of macrophages. Adult horse monocyte-derived macrophages were incubated with Rhodococcus equi for 4h either in the mucus layer of in vitro generated airway epithelium or on collagen coated membranes.

Equine bronchial epithelial cells differentiate into ciliated and mucus producing cells in vitro.

We describe a method for creating differentiated equine bronchial epithelial cell cultures that can be used for in vitro studies including airway disease mechanisms and pathogen-host interactions. Our method is based on the culturing of human tracheobronchial epithelial cells at an air-liquid interface (ALI) in specific serum-free, hormone-supplemented medium. Bronchial epithelial cells are isolated and grown on T-Clear® insert membranes.

Transcriptional responses of Mycobacterium tuberculosis to lung surfactant.

This study uses microarray analyses to examine gene expression profiles for Mycobacterium tuberculosis (Mtb) induced by exposure in vitro to bovine lung surfactant preparations that vary in apoprotein content: (i) whole lung surfactant (WLS) containing the complete mixture of endogenous lipids and surfactant proteins (SP)-A, -B, -C, and -D; (ii) extracted lung surfactant (CLSE) containing lipids plus SP-B and -C; (iii) column-purified surfactant lipids (PPL) containing no apoproteins, and (iv) purified human SP-A. Exposure to WLS evoked a multitude of transcriptional responses in Mtb, with 52 genes up-regulated and 23 genes down-regulated at 30min exposure, plus 146 genes up-regulated and 27 genes down-regulated at 2h. Notably, WLS rapidly induced several membrane-associated lipases that presumptively act on surfactant lipids as substrates, and a large number of genes involved in the synthesis of phthiocerol dimycocerosate (PDIM), a cell wall component known to be important in macrophage interactions and Mtb virulence.

Peripheral cell wall lipids of Mycobacterium tuberculosis are inhibitory to surfactant function.

The transmission of Mycobacterium tuberculosis (TB) requires extensive damage to the lungs to facilitate bacterial release into the airways, and it is therefore likely that the microorganism has evolved mechanisms to exacerbate its local pathology. This study examines the inhibitory effects of lipids extracted and purified chromatographically from TB on the surface-active function of lavaged bovine lung surfactant (LS) and a clinically relevant calf lung surfactant extract (CLSE). Total lipids from TB greatly inhibited the surface activity of LS and CLSE on the pulsating bubble surfactometer at physical conditions applicable for respiration in vivo (37 degrees C, 20 cycles/min, 50% area compression).

Phenotypic and transcriptomic analyses demonstrate interactions between the transcriptional regulators CtsR and Sigma B in Listeria monocytogenes.

Listeria monocytogenes sigma(B) positively regulates the transcription of class II stress response genes; CtsR negatively regulates class III stress response genes. To identify interactions between these two stress response systems, we constructed L. monocytogenes DeltactsR and DeltactsR DeltasigB strains, as well as a DeltactsR strain expressing ctsR in trans under the control of an IPTG (isopropyl-beta-d-thiogalactopyranoside)-inducible promoter.

Evaluation of the pathogenicity of Listeria spp. in Caenorhabditis elegans.

Caenorhabditis has proven to be a useful model for studying host-pathogen interactions as well as the ability of nematodes to serve as vectors for the dispersal of foodborne pathogens. In this study, we evaluated whether C. elegans can serve as a host for Listeria spp.

A physical linkage between cystic fibrosis airway surface dehydration and Pseudomonas aeruginosa biofilms.

A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high prevalence of Pseudomonas aeruginosa biofilms in CF airways. We speculated that airway surface liquid (ASL) hyperabsorption generates a concentrated airway mucus that interacts with P. aeruginosa to promote biofilms.

Reduced three-dimensional motility in dehydrated airway mucus prevents neutrophil capture and killing bacteria on airway epithelial surfaces.

Cystic fibrosis (CF) lung disease is characterized by persistent lung infection. Thickened (concentrated) mucus in the CF lung impairs airway mucus clearance, which initiates bacterial infection. However, airways have other mechanisms to prevent bacterial infection, including neutrophil-mediated killing.

The Listeria monocytogenes prfAP2 promoter is regulated by sigma B in a growth phase dependent manner.

Listeria monocytogenes prfA, encoding positive regulatory factor A, is transcribed from three promoters (prfAP1, prfAP2, and PplcA). The prfAP2 promoter was previously proposed to be sigma B (sigma(B))-dependent. This hypothesis was tested by creating prfA promoter-gus transcriptional fusions in both L.

Identification of N-acylhomoserine lactones in mucopurulent respiratory secretions from cystic fibrosis patients.

Pseudomonas aeruginosa and species of the Burkholderia cepacia complex are the primary bacterial pathogens contributing to lung disease in patients with cystic fibrosis. Quorum sensing systems using N-acyl homoserine lactone (AHL) signal molecules are involved in the regulation of a number of virulence factors in these species. Extracts of mucopurulent respiratory secretions from 13 cystic fibrosis patients infected with P.

Chronic airway infection/inflammation induces a Ca2+i-dependent hyperinflammatory response in human cystic fibrosis airway epithelia.

Hyperinflammatory responses to infection have been postulated as a component of cystic fibrosis (CF) lung disease. Studies have linked intracellular calcium (Ca(2+)(i)) mobilization with inflammatory responses in several systems. We have reported that the pro-inflammatory mediator bradykinin (BK) promotes larger Ca(2+)(i) signals in CF compared with normal bronchial epithelia, a response that reflects endoplasmic reticulum (ER)/Ca(2+) store expansion induced by chronic luminal airway infection/inflammation.

Alternative sigma factor sigmaB is not essential for listeria monocytogenes surface attachment.

Listeria monocytogenes is a foodborne pathogen frequently isolated from the food processing environment. Multiple lines of evidence suggested a possible role for the L. monocytogenes alternative transcription factor sigma B (sigmaB) in surface attachment and biofilm formation.

Human THP-1 monocyte uptake and cellular disposition of 14C-grepafloxacin.

Uptake of (14)C-grepafloxacin into human mononuclear (THP-1) cells was determined at pH 7.4, 6.8, or 5.

Disposition and intracellular levels of moxifloxacin in human THP-1 monocytes in unstimulated and stimulated conditions.

Moxifloxacin uptake by human THP-1 monocytes was passive and initially linear and reached equilibrium after approximately 4 h. High intracellular concentrations were achieved and intracellular/extracellular [I/E] ratios were between 1925 and 4575 for the lowest concentration of 0.004 microg/ml at pH 7.

Role of actin filament network in Burkholderia multivorans invasion in well-differentiated human airway epithelia.

The role of the actin-based cytoskeleton in the internalization process of Burkholderia multivorans by well-differentiated human airway epithelia was investigated by immunohistology and confocal microscopy. Our data suggest that an intact actin cytoskeleton is required for biofilm formation but not single cell entry or paracytosis.

Effects of alatrofloxacin, the parental prodrug of trovafloxacin, on phagocytic, anti-inflammatory and immunomodulation events of human THP-1 monocytes.

Alatrofloxacin functions similar to other fluoroquinolone antibiotics in that it not only has antibiotic activity to kill invading organisms by interfering with DNA synthesis, it possesses immunosuppressive activity. In the first hour after bacteria have been phagocytosed by THP-1 monocytes, the drug activates a lytic mechanism involving the release of c-AMP, tumor necrosis factor (TNFalpha), interleukin-1 (IL-1), IL-6 and nitric oxide, with elevations in lysosomal hydrolytic enzyme activities. This effect reverses between 2 and 4 h.

Effects of moxifloxacin in zymogen A or S. aureus stimulated human THP-1 monocytes on the inflammatory process and the spread of infection.

Antimicrobial agents have been reported to exhibit immunomodulatory and anti-inflammatory activities, both in vivo and in vitro (e.g., in human lymphocytes, macrophages and monocytes).

In-vitro anti-inflammatory and immunomodulatory effects of grepafloxacin in zymogen A- or Staphylococcus aureus-stimulated human THP-1 monocytes.

The effects of grepafloxacin on the release of cytokines, chemical mediators, hydrolytic enzyme activities, and lipoxygenation in zymogen A- or Staphylococcus aureus-stimulated human THP-1 monocytes were evaluated. Initially, consistent with stimulation of phagocytic mechanisms of the monocytes, increases in cyclic adenosine monophosphate (cAMP) release, nitric oxide [NO] release, and hydrogen peroxide [H(2)O(2)] release, with a small decrease in cellular pH, occurred within 2 h. Enzymatic activities associated with oxygen burst of phagocytic cells (e.

Disposition and intracellular activity of azithromycin in human THP-1 acute monocytes.

Uptake of [14C]-azithromycin into THP-1 human monocytes was determined at pH 7.4, 6.8 or 5.

Pseudomonas aeruginosa anaerobic respiration in biofilms: relationships to cystic fibrosis pathogenesis.

Recent data indicate that cystic fibrosis (CF) airway mucus is anaerobic. This suggests that Pseudomonas aeruginosa infection in CF reflects biofilm formation and persistence in an anaerobic environment. P.

A bacterial cell to cell signal in the lungs of cystic fibrosis patients.

Pseudomonas aeruginosa is an opportunistic pathogen that is a major cause of mortality in cystic fibrosis (CF) patients. This bacterium has numerous genes controlled by cell to cell signaling, which occurs through a complex circuitry of interconnected regulatory systems. One of the signals is the Pseudomonas Quinolone Signal (PQS), which was identified as 2-heptyl-3-hydroxy-4-quinolone.

Patterns of epithelial cell invasion by different species of the Burkholderia cepacia complex in well-differentiated human airway epithelia.

Burkholderia cepacia has emerged as a serious respiratory pathogen in cystic fibrosis (CF) patients. The clinical course of B. cepacia infections is variable, but approximately 20% of patients eventually succumb to the cepacia syndrome, which is characterized as a fatal necrotizing pneumonia with bacteremia.

Effects of reduced mucus oxygen concentration in airway Pseudomonas infections of cystic fibrosis patients.

Current theories of CF pathogenesis predict different predisposing "local environmental" conditions and sites of bacterial infection within CF airways. Here we show that, in CF patients with established lung disease, Pseudomonas aeruginosa was located within hypoxic mucopurulent masses in airway lumens. In vitro studies revealed that CF-specific increases in epithelial O(2) consumption, linked to increased airway surface liquid (ASL) volume absorption and mucus stasis, generated steep hypoxic gradients within thickened mucus on CF epithelial surfaces prior to infection.