Bettina C. Schock

Bronchoalveolar lavage findings suggest two different forms of childhood asthma

Background It seems plausible that children with atopy and persistent asthma symptoms will, like their adult counterparts, have chronic airways inflammation. However, many young children with no other atopic features have episodic wheezing that is triggered solely by viral respiratory infections. Little is known as to whether airways inflammation occurs in these two asthma patterns during relatively asymptomatic periods.

Gene expression profile of oxidant stress and neurodegeneration in transgenic mice deficient in α-tocopherol transfer protein

Alpha-tocopherol transfer protein (TTP) regulates the retention and secretion of alpha-tocopherol (alpha-T) by the liver. Deletion of the TTP gene (Ttpa) in mice results in systemic deficiency of alpha-T and neurological dysfunctions described in patients with mutated Ttpa. We have explored genome-wide changes in mRNAs from brain cortex and liver of Ttpa-deficient (Ttpa(-/-)) mice and wild-type (Ttpa(+/+)) mice. Selective inductions of genes regulated by antioxidant response elements were detected in Ttpa(-/-) livers compared to Ttpa(+/+) livers, suggesting increased oxidant stress in Ttpa(-/-) livers. The activation of cell proliferation pathways in Ttpa(-/-) livers was indicated by the induction of genes that encode growth factor-binding proteins, mitogen-activated protein kinase kinase 3, and apoptosis inhibitor 6. The induction of synuclein-alpha and repression of synuclein-beta genes was detected in Ttpa(-/-) cortex. This may predispose Ttpa(-/-) cortex to increased formation of synuclein-alpha aggregates and Lewy body, often associated with oxidant stress. Cortex of Ttpa(-/-) mice revealed repression of genes encoding synaptic proteins, protein kinase C family members, and myelin proteins. A 13-fold decrease in the expression of retinoic acid receptor-related orphan receptor-alpha mRNA predicts staggerer-like phenotype (ataxia and deficits of motor coordination) of Ttpa(-/-) mice. The repression of specific genes that determine synaptic plasticity and neuronal development may account for suppressed electrophysiological activities of cortex and impaired behavior in Ttpa(-/-) mice.

Ozone exposure activates oxidative stress responses in murine skin.

Ozone (O(3)) is among the most reactive environmental oxidant to which skin is exposed. O(3) exposure has previously been shown to induce antioxidant depletion as well as lipid and protein oxidation in the outermost skin layer, the stratum corneum (SC), but little is known regarding the potential effects of O(3) on the skin epidermis and dermis. To evaluate such skin responses to O(3), SKH-1 hairless mice were exposed for 2 h to 8.0 ppm O(3) or to ambient air. O(3) exposure caused a significant increase in skin carbonyls (28%) compared to the skin of air exposed control animals. An evident increase in 4-hydroxynonenal-protein adducts was detected after O(3) exposure. O(3) exposure caused a rapid up-regulation of HSP27 (20-fold), and more delayed induction of HSP70 (2.8-fold) and heme oxygenase-1 (5-fold). O(3) exposure also led to the induction of nitric oxide synthase (iNOS) 6-12 h following O(3) exposure. We conclude that skin exposure to high levels of O(3) not only affects antioxidant levels and oxidation markers in the SC, but also induces stress responses in the active layers of the skin, most likely by indirect mechanisms, since it is unlikely that O(3) itself penetrates the protective SC layers.

Oxidative stress and increased type-IV collagenase levels in bronchoalveolar lavage fluid from newborn babies

Oxidative stress may increase lung permeability by up-regulation of matrix-metalloproteinase-9 (MMP-9), a type-IV collagenase that can disrupt alveolar basement membranes. We have compared a marker of oxidative stress (protein carbonyl residues) with levels of MMP-9 and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), in bronchoalveolar lavage samples from newborn babies. Bronchoalveolar lavage samples (n = 87, two from each time point) were taken in the first 6 postnatal days from 41 ventilated babies: 18 of <29 wk gestation, 10 of 29–36 wk, 9 term with persistent fetal circulation, and 4 term without lung disease. Respiratory disease severity at the time of bronchoalveolar lavage was assessed using the arterial–alveolar oxygen tension ratio. One sample from each time point was used for the measurement of MMP-9 by zymography and TIMP-1 by ELISA. The second sample was used to measure carbonyl group concentrations, also using an ELISA. Correlations were calculated between protein carbonyls, arterial–alveolar oxygen tension ratio, and MMP-9 and TIMP-1 concentrations. Significant correlations were found between carbonyl concentrations and arterial–alveolar oxygen tension ratio (r = −0.325, p = 0.0031, n = 81), MMP-9 (r = 0.331, p < 0.0029, n = 79), and TIMP-1 (r = 0.436, p < 0.0001, n = 87). Worsening respiratory disease in newborn babies is associated with increased carbonyl concentrations in neonatal bronchoalveolar lavage fluid, and these correlated with MMP-9 and TIMP-1 levels. Increased oxidative stress may damage the lung by increasing type-IV collagenase activity, causing disruption of the extracellular matrix.

Evaluation of the Ability of LL-37 to Neutralise LPS In Vitro and Ex Vivo

Background Human cathelicidin LL-37 is a cationic antimicrobial peptide (AMP) which possesses a variety of activities including the ability to neutralise endotoxin. In this study, we investigated the role of LPS neutralisation in mediating LL-37s ability to inhibit Pseudomonas aeruginosa LPS signalling in human monocytic cells. Methodology/Principal Findings Pre-treatment of monocytes with LL-37 significantly inhibited LPS-induced IL-8 production and the signalling pathway of associated transcription factors such as NF-κB. However, upon removal of LL-37 from the media prior to LPS stimulation, these inhibitory effects were abolished. These findings suggest that the ability of LL-37 to inhibit LPS signalling is largely dependent on extracellular LPS neutralisation. In addition, LL-37 potently inhibited cytokine production induced by LPS extracted from P. aeruginosa isolated from the lungs of cystic fibrosis (CF) patients. In the CF lung, polyanionic molecules such as glycosaminoglycans (GAGs) and DNA bind LL-37 and impact negatively on its antibacterial activity. In order to determine whether such interactions interfere with the LPS neutralising ability of LL-37, the status of LL-37 and its ability to bind LPS in CF sputum were investigated. Overall our findings suggest that in the CF lung, the ability of LL-37 to bind LPS and inhibit LPS-induced IL-8 production is attenuated as a result of binding to DNA and GAGs. However, LL-37 levels and its concomitant LPS-binding activity can be increased with a combination of DNase and GAG lyase (heparinase II) treatment. Conclusions/Significance Overall, these findings suggest that a deficiency in available LL-37 in the CF lung may contribute to greater LPS-induced inflammation during CF lung disease.

Neutrophils and Eosinophils: Clinical Implications of their Appearance, Presence and Disappearance in Asthma and COPD

Asthma and chronic obstructive pulmonary disease (COPD) are common chronic disorders. Traditionally, asthma has been associated with an eosinophilic inflammation and COPD with neutrophilic inflammation. In this review we will highlight the maturation, recruitment, activation, action and apoptosis of these cells. In addition we will focus on the evidence for their presence in disease and suggest potential new therapeutic interventions.

Role of CFTR, Pseudomonas aeruginosa and Toll-like receptors in cystic fibrosis lung inflammation.

CF (cystic fibrosis) is a severe autosomal recessive disease most common in Northwest European populations. Underlying mutations in the CFTR (CF transmembrane conductance regulator) gene cause deregulation of ion transport and subsequent dehydration of the airway surface liquid, producing a viscous mucus layer on the airway surface of CF patients. This layer is readily colonized by bacteria such as Pseudomonas aeruginosa. Owing to the resulting environment and treatment strategies, the bacteria acquire genetic modifications such as antibiotic resistance, biofilm formation, antimicrobial peptide resistance and pro-inflammatory lipid A structures. Lipid A is a component of the lipopolysaccharide cell wall present on bacteria and is recognized by TLR4 (Toll-like receptor 4). Its detection elicits a pro-inflammatory response that is heightened over time due to the addition of fatty acids to the lipid A structure. Eradication of bacteria from the lungs of CF patients becomes increasingly difficult and eventually leads to mortality. In the present review, we describe the role of lipid A as a virulent factor of Ps. aeruginosa; however, it appears that further work is needed to investigate the role of CFTR in the innate immune response and in modifying the pathogen-host interaction.

Inflammatory mediators in bronchoalveolar lavage samples from children with and without asthma

We investigated whether eosinophils and mast cells, found in the airways of children with wheeze, were activated during relatively asymptomatic periods.

Increased concentrations of the oxidative DNA adduct 7, 8-dihydro-8-oxo-2-deoxyguanosine in the germ-line of men with type 1 diabetes

The effects of diabetes mellitus on male reproductive health have not been clearly defined. A previous publication from this group reported significantly higher levels of nuclear DNA fragmentation and mitochondrial DNA deletions in spermatozoa from men with type 1 diabetes. This study compared semen profiles, sperm DNA fragmentation and levels of oxidative DNA modification in spermatozoa of diabetic and non-diabetic men. Semen samples from 12 non-diabetic, fertile men and 11 type 1 diabetics were obtained and subjected to conventional light microscopic semen analysis. Nuclear DNA fragmentation was assessed using an alkaline Comet assay and concentrations of 7,8-dihydro-8-oxo-2-deoxyguanosine (8-OHdG), an oxidative adduct of the purine guanosine, were assessed by high-performance liquid chromatography. Conventional semen profiles were similar in both groups, whilst spermatozoa from type 1 diabetics showed significantly higher levels of DNA fragmentation (44% versus 27%; P < 0.05) and concentrations of 8-OHdG (3.6 versus 2.0 molecules of 8-OHdG per 10(5) molecules of deoxyguanosine; P < 0.05). Furthermore, a positive correlation was observed between DNA fragmentation and concentrations of 8-OHdG per 10(5) molecules of deoxyguanosine (rs = 0.7, P < 0.05). The genomic damage evident in spermatozoa of type 1 diabetics may have important implications for their fertility and the outcome of pregnancies fathered by these individuals.

α‐Tocopherol Transfer Protein Deficiency in Mice Causes Multi‐Organ Deregulation of Gene Networks and Behavioral Deficits with Age

Abstract: Functions of α‐tocopherol (α‐T) in vivo, other than those for fertility in females, are intensely debated. The discovery of α‐T deficiency in patients with ataxia (AVED) followed by the identification of mutations in the gene encoding α‐tocopherol transfer protein (TTP) in AVED patients demonstrates an essential role of α‐T and TTP for normal neurological function. α‐T molecular targets that account for α‐T‐sensitive neurological dysfunction remain to be discovered. We have used high‐density oligonucleotide arrays to search for putative α‐T‐sensitive genes in the CNS and other tissues in an in vivo model of α‐T deficiency imposed at birth by the deletion of the TTP gene in mice. Repression of genes affecting synaptic function and myelination and induction of genes for neurodegeneration in the motor cortex of α‐T‐deficient mice were identified. The expression of retinoic acid‐related orphan receptor alpha (ROR‐α) was repressed in the cortex and adrenal glands of TTP‐deficient mice. Deficiency of ROR‐α causes ataxia in mice and may account for ataxia in AVED patients. These observations suggest that some of the actions of α‐T are mediated by the transcription factor ROR‐α. The behavior of young TTP‐null mice was essentially normal, but older mice showed inactivity, ataxia, and memory dysfunction. mRNA profiles of old α‐T‐deficient cerebral cortices are compatible with repressed activity of oligodendrocytes and astrocytes. In conclusion, gene‐expression profiling studies have identified novel α‐T‐modulated genes and cells in the CNS that may be causatively linked with delayed neurodegeneration and age‐related decline in behavioral repertoires.