Lung Epithelial Injury by B. Anthracis Lethal Toxin Is Caused by MKK-Dependent Loss of Cytoskeletal Integrity

Bacillus anthracis lethal toxin (LT) is a key virulence factor of anthrax and contributes significantly to the in vivo pathology. The enzymatically active component is a Zn2+-dependent metalloprotease that cleaves most isoforms of mitogen-activated protein kinase kinases (MKKs). Using ex vivo differentiated human lung epithelium we report that LT destroys lung epithelial barrier function and wound healing responses by immobilizing the actin and microtubule network. Long-term exposure to the toxin generated a unique cellular phenotype characterized by increased actin filament assembly, microtubule stabilization, and changes in junction complexes and focal adhesions. LT-exposed cells displayed randomly oriented, highly dynamic protrusions, polarization defects and impaired cell migration. Reconstitution of MAPK pathways revealed that this LT-induced phenotype was primarily dependent on the coordinated loss of MKK1 and MKK2 signaling. Thus, MKKs control fundamental aspects of cytoskeletal dynamics and cell motility. Even though LT disabled repair mechanisms, agents such as keratinocyte growth factor or dexamethasone improved epithelial barrier integrity by reducing cell death. These results suggest that co-administration of anti-cytotoxic drugs may be of benefit when treating inhalational anthrax

Subjective and objective halitosis among patients with Parkinson's disease

ObjectivesParkinson's disease (PD) affects oral health, but prevalence of subjective and objective halitosis and the influence of hyposalivation remain unclear. We aimed to explore whether patients with PD suffer from halitosis and to define correlations between halitosis and hyposalivation. We hypothesised that patients with PD suffer more often from halitosis compared to healthy controls, influenced by dry mouth. Materials and methodsSubjective (halitosis, xerostomia visual analogue scale [VAS], short German Oral Health Impact Profile [OHIPG]-14) and objective scales (e.g., organoleptic score, volatile sulphur compounds [VSCs], stimulated whole saliva [SWS]) were assessed from 26 patients with PD and 26 healthy controls. ResultsThe mean organoleptic score was 0.7 (SD: 0.7) in all patients, and VSCs were either comparable or significantly lower (dimethyl sulphide, P=.010) in PD patients compared with controls, yet more patients with PD perceived halitosis to be stronger (77% vs 54%, respectively; P=.059). Dry mouth was significantly more likely in patients with PD than controls: mean xerostomia VAS 4 (SD: 2) vs 1 (SD: 2), P=.010; SWS 0.4 (SD: 0.4) vs 0.7 (SD: 0.6) mL/min, P<.05); SWS did not correlate with subjective or objective halitosis. Oral health-related quality of life (OHRQoL) was lower in patients with PD than controls (mean OHIPG-14 score 12 (SD: 0.2) vs 5 (SD: 7.0), respectively; P<.05). ConclusionsPatients with PD suffer from subjective and objective halitosis, dry mouth and impaired OHRQoL. Dry mouth problems do not correlate with prevalence or intensity of halitosis

Structural Insights into Nox4 and Nox2: Motifs Involved in Function and Cellular Localization ▿ †

Regulated generation of reactive oxygen species (ROS) is primarily accomplished by NADPH oxidases (Nox). Nox1 to Nox4 form a membrane-associated heterodimer with p22phox, creating the docking site for assembly of the activated oxidase. Signaling specificity is achieved by interaction with a complex network of cytosolic components. Nox4, an oxidase linked to cardiovascular disease, carcinogenesis, and pulmonary fibrosis, deviates from this model by displaying constitutive H2O2 production without requiring known regulators. Extensive Nox4/Nox2 chimera screening was initiated to pinpoint structural motifs essential for ROS generation and Nox subcellular localization. In summary, a matching B loop was crucial for catalytic activity of both Nox enzymes. Substitution of the carboxyl terminus was sufficient for converting Nox4 into a phorbol myristate acetate (PMA)-inducible phenotype, while Nox2-based chimeras never gained constitutive activity. Changing the Nox2 but not the Nox4 amino terminus abolished ROS generation. The unique heterodimerization of a functional Nox4/p22phox Y121H complex was dependent on the D loop. Nox4, Nox2, and functional Nox chimeras translocated to the plasma membrane. Cell surface localization of Nox4 or PMA-inducible Nox4 did not correlate with O2− generation. In contrast, Nox4 released H2O2 and promoted cell migration. Our work provides insights into Nox structure, regulation, and ROS output that will aid inhibitor design

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

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

Objective masticatory efficiency and subjective quality of masticatory function among patients with periodontal disease

Aims To examine patient-centred clinical outcomes for objective masticatory efficiency (OME) and subjective quality of masticatory function (QMF) among periodontitis patients using test methods easily applicable in daily practice. Materials and Methods Cross-sectional investigation of patients undergoing supportive periodontal therapy (n = 224). Outcomes included OME and QMF related to periodontitis characteristics. Results OME and QMF were associated (x(2) = 0.252,p = 0.037) and showed highest values in stage 4 according to the new classification of periodontal disease. There were correlations particularly in stage 2 between OME and number of teeth (x(2) = -0.317,p < 0.001), Quigley-Hein Index (x(2) = 0.152,p = 0.031), attachment level (x(2) = 0.268,p < 0.001), probing depths (x(2) = 0.185,p = 0.006), tooth mobility (x(2) = 0.147,p = 0.031) and functional occlusal units (x(2) = -0.423,p < 0.001) but not bleeding on probing. A trend existed between QMF and number of teeth (x(2) = -0.237,p = 0.050) and functional occlusal units (x(2) = 0.238,p = 0.058), but not other periodontal findings. Conclusions OME and QMF values represent each other and are highest in stage 4. Periodontitis findings influence masticatory efficiency particularly in stage 2, but gingival inflammation does not. Number of teeth and functional occlusal units are associated with QMF, while periodontitis findings have less impact. An assessment of mastication should be routinely included in the diagnosis of periodontitis patients in all stages

Molecular analysis of chronic granulomatous disease and site-direted mutagenesis as models to solve the naden oxidase puzzle

IP 1115-04-476-96ARTICULO(S) EN REVISTA: Recombination events between the p47 phox gene andits highly homologous pseudogenes;are the main cause of autosomal recessive chronic granulomatusdisease / Joachim Roesler ... [et al.]. -- En:;Blood. -- Vol.95, no. 6 (Mar. 2000); p. 2150-2156. -- Molecularcharacterization of autosomal recessive;chronic granulomatous disease caused by a defect of the nicotinamide adenine dinucleotide phosphate (reduced;form) oxidase component p67 phox / Pablo J. Patiño ... [etal.].'-- en: Blood. -- Vol. 94, no. 7 (1999); p.;2505-2514. -- Molecular analysis of chronic granulomatousdisease caused by defects in gp91 phox / Pablo J.;Patiño ... [et al.]. -- En: Human Mutation. -- no. 13 (1999);p.29-37. --Caracterizacion clinico molecular;de la enfermedad granulomatosa cronica autosomica recesivacausada por deficit de p47-phox / Monica Cornejo de;L. --- [et al.]. -- En: Revista Medica de Chile. -- Vol. 128 (2000); p.490-498