In vitro-generated respiratory mucosa: a new tool to study inhalational anthrax

Radyuk, Svetlana N.; Mericko, Patricia; Popova, Taissia G.; Grene, Edith; Alibek, Ken

doi:10.1016/s0006-291x(03)00830-1

Cited by 32 publications

(28 citation statements)

References 28 publications

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“…However, we did not observe a decrease in bacterial viability during incubation of CapD-treated bacilli in mouse serum (data not shown). Some antimicrobial peptides or defensins are bactericidal for B. anthracis (29,36,41), and capsule does confer some resistance (33). Future studies will determine if CapD treatment sensitizes bacilli to antimicrobial peptides.…”

Section: Discussionmentioning

confidence: 99%

Treatment of Experimental Anthrax with Recombinant Capsule Depolymerase

Scorpio

Tobery

Ribot

et al. 2008

Antimicrob Agents Chemother

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Bacillus anthracis produces an antiphagocytic gamma-linked poly-D-glutamic acid capsule that is required for virulence. Capsule depolymerase (CapD) is a membrane-associated poly-␥-glutamate-specific depolymerase encoded on the B. anthracis capsule plasmid, pX02, that is reported to contribute to virulence by anchoring the capsule to the peptidoglycan and partially degrading high-molecular-weight capsule from the bacterial surface. We previously demonstrated that treatment with CapD effectively removes the capsule from anthrax bacilli, rendering them susceptible to phagocytic killing in vitro. Here we report that CapD promoted in vivo phagocytic killing of B. anthracis bacilli by mouse peritoneal neutrophils and that parenteral administration of CapD protected mice in two models of anthrax infection. CapD conferred significant protection compared with controls when coinjected with encapsulated bacilli from fully virulent B. anthracis Ames or the nontoxigenic encapsulated strain ⌬Ames and when injected 10 min after infection with encapsulated bacilli from B. anthracis Ames. Protection was also observed when CapD was administered 30 h after infection with B. anthracis ⌬Ames spores, while significant protection could not be demonstrated following challenge with B. anthracis Ames spores. These data support the proposed role of capsule in B. anthracis virulence and suggest that strategies to target anthrax bacilli for neutrophil killing may lead to novel postexposure therapies.

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Section: Discussionmentioning

confidence: 99%

Treatment of Experimental Anthrax with Recombinant Capsule Depolymerase

Scorpio

Tobery

Ribot

et al. 2008

Antimicrob Agents Chemother

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“…Furthermore, lung epithelial cells secrete antimicrobial peptides and proteins (19,21,40) that could inactivate B. anthracis cells. In a model system using human airway tissue, B. anthracis spores are either killed by epithelial cells or phagocytized by macrophages where germination and subsequent bacillus release occurs (28).…”

Section: Discussionmentioning

confidence: 99%

Bacillus anthracis Spores of the bclA Mutant Exhibit Increased Adherence to Epithelial Cells, Fibroblasts, and Endothelial Cells but Not to Macrophages

Bozue¹,

Moody²,

Cote³

et al. 2007

Infect Immun

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Bacillus anthracis is the causative agent of anthrax, and the spore form of the bacterium represents the infectious particle introduced into a host. The spore is surrounded by an exosporium, a loose-fitting membrane composed of proteins and carbohydrates from which hair-like projections extend. These projections are composed mainly of BclA (Bacillus-collagen-like protein of B. anthracis). To date, exact roles of the exosporium structure and BclA protein remain undetermined. We examined differences in spore binding of wild-type Ames and a bclA mutant of B. anthracis to bronchial epithelial cells as well as to the following other epithelial cells: A549, CHO, and Caco-2 cells; the IMR-90 fibroblast line; and human umbilical vein vascular endothelium cells. The binding of wild-type Ames spores to bronchial epithelial cells appeared to be a dose-dependent, receptor-ligand-mediated event. There were similar findings for the bclA mutant, with an additional nonspecific binding component likely leading to significantly more adherence to all nonprofessional phagocytic cell types. In contrast, we detected no difference in adherence and uptake of spores by macrophages for either the wild-type Ames or the bclA mutant strain. These results suggest that one potential role of the BclA fibers may be to inhibit nonspecific interactions between B. anthracis spores with nonprofessional phagocytic cells and thus direct the spores towards uptake by macrophages during initiation of infection in mammals.Bacillus anthracis, a gram-positive, spore-forming bacillus, is the causative agent of anthrax (11,25). The spore structure of B. anthracis consists of overlapping layers called the core, cortex, coat, and exosporium (9). The central interior of a spore, known as the core, houses the chromosome. The cortex is a thick layer of peptidoglycan that surrounds the core (27), which is then further enveloped by the spore coat (1). The outermost structure of the B. anthracis spore is a loose-fitting exosporium (12). Approximately 20 exosporium-associated proteins and glycoproteins have been identified from analyses of B. anthracis and Bacillus cereus spores (4,5,29,(35)(36)(37)(38)(39). The exosporium membrane projects hair-like fibers (12) of which the major component is the BclA glycoprotein (35, 37).Fibers of the B. anthracis exosporium were once believed to be important for virulence or adherence to host cells (20). However, several studies have demonstrated that the fibers and exosporium are not necessary for full virulence of B. anthracis. Upon identifying the BclA protein, Sylvestre et al. (37) examined the effect of a bclA mutation on the virulence of the attenuated Sterne strain of B. anthracis. In this first study, when spores were administered subcutaneously to mice, no appreciable differences in virulence were observed between the parental Sterne and bclA mutant strains (37). We recently showed that by using a fully virulent strain of B. anthracis, an Ames bclA mutant retains complete virulence in mouse and guinea pig models of anthr...

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“…For re-differentiation and formation of a three-dimensional (3D) polarized epithelium, cells were grown at the air-liquid interphase (ALI) according to the method of Radyuk et al (Radyuk et al, 2003). Briefly, cells were seeded on collagen-coated (type IV, 15 μg/cm 2 ; Sigma, St Louis, MO) semi-permeable membranes (0.4 μm pore; Corning Costar Transwell Clear), in serum-free culture medium, consisting of 50% DMEM high glucose (Invitrogen, Carlsbad, CA) and 50% bronchial epithelial cell basal medium (BEBM; Lonza), supplemented with growth factors (BEGM singlequots; Lonza) and 50 nM retinoic acid (Sigma).…”

Section: Cell Culture and Cell Transfectionmentioning

confidence: 99%

Heterodimerization controls localization of Duox-DuoxA NADPH oxidases in airway cells

Luxen

Noack

Frausto

et al. 2009

Journal of Cell Science

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Duox NADPH oxidases generate hydrogen peroxide at the air-liquid interface of the respiratory tract and at apical membranes of thyroid follicular cells. Inactivating mutations of Duox2 have been linked to congenital hypothyroidism, and epigenetic silencing of Duox is frequently observed in lung cancer. To study Duox regulation by maturation factors in detail, its association with these factors, differential use of subunits and localization was analyzed in a lung cancer cell line and undifferentiated or polarized lung epithelial cells. We show here that Duox proteins form functional heterodimers with their respective DuoxA subunits, in close analogy to the phagocyte NADPH oxidase. Characterization of novel DuoxA1 isoforms and mispaired Duox-DuoxA complexes revealed that heterodimerization is a prerequisite for reactive oxygen species production. Functional Duox1 and Duox2 localize to the leading edge of migrating cells, augmenting motility and wound healing. DuoxA subunits are responsible for targeting functional oxidases to distinct cellular compartments in lung epithelial cells, including Duox2 expression in ciliated cells in an ex vivo differentiated lung epithelium. As these locations probably define signaling specificity of Duox1 versus Duox2, these findings will facilitate monitoring Duox isoform expression in lung disease, a first step for early screening procedures and rational drug development.

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In vitro-generated respiratory mucosa: a new tool to study inhalational anthrax

Cited by 32 publications

References 28 publications

Treatment of Experimental Anthrax with Recombinant Capsule Depolymerase

Treatment of Experimental Anthrax with Recombinant Capsule Depolymerase

Bacillus anthracis Spores of the bclA Mutant Exhibit Increased Adherence to Epithelial Cells, Fibroblasts, and Endothelial Cells but Not to Macrophages

Heterodimerization controls localization of Duox-DuoxA NADPH oxidases in airway cells

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