Regulation of cytokine gene expression by reactive oxygen and reactive nitrogen intermediates

Reactive oxygen intermediates (ROI), reactive nitrogen intermediates (RNI), and cytokines are frequent companions at sites of acute inflammation. Previous work has established a clear link between the production of cytokines and the subsequent generation of ROI and RNI. However, more recent data indicates that ROI and RNI not only serve as end‐stage effector molecules of pathogen destruction and tissue injury, but also as initiators of acute inflammation. Specifically, ROI and RNI will up‐regulate cytokine gene expression since antioxidants inhibit interleukin 8 (IL‐8) production and do not decrease production of other cytokines. Treatment with hydroxyl radical scavengers such as dimethyl sulfoxide (DMSO) will decrease the production of IL‐8 in stimulated human whole blood, fibroblasts, type II epithelial cells, and hepatoma cells, but not other cytokines. Addition of exogenous ROI will increase IL‐8 production in these same cells. Inhibition of nitric oxide synthase will decrease production of IL‐8, whereas addition of nitric oxide (NO)‐generating compounds will increase production of IL‐8. The hydroxyl radical appears to be the final common pathway of cell activation for IL‐8 synthesis, since DMSO will inhibit the NO‐driven production of IL‐8. Our data indicate that ROI and RNI can serve as intracellular second messengers to induce IL‐8 gene expression.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141605/1/jlb0471.pd

Promoter Elements Responsible for Antioxidant Regulation of MCP-1 Gene Expression

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63401/1/ars.2007.1921.lowlink.pdf_v03.pd

Lung and gut injury induced by tumour necrosis factor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31074/1/0000751.pd

Allergens induce enhanced bronchoconstriction and leukotriene production in C5 deficient mice

Abstract Background Previous genetic analysis has shown that a deletion in the complement component 5 gene-coding region renders mice more susceptible to allergen-induced airway hyperresponsiveness (AHR) due to reduced IL-12 production. We investigated the role of complement in a murine model of asthma-like pulmonary inflammation. Methods In order to evaluate the role of complement B10 mice either sufficient or deficient in C5 were studied. Both groups of mice immunized and challenged with a house dust extract (HDE) containing high levels of cockroach allergens. Airways hyper-reactivity was determined with whole-body plesthysmography. Bronchoalveolar lavage (BAL) was performed to determine pulmonary cellular recruitment and measure inflammatory mediators. Lung homogenates were assayed for mediators and plasma levels of IgE determined. Pulmonary histology was also evaluated. Results C5-deficient mice showed enhanced AHR to methylcholine challenge, 474% and 91% increase above baseline Penh in C5-deficient and C5-sufficient mice respectively, p < 0.001. IL-12 levels in the lung homogenate (LH) were only slightly reduced and BAL IL-12 was comparable in C5-sufficient and C5-deficient mice. However, C5-deficient mice had significantly higher cysteinyl-leukotriene levels in the BAL fluid, 1913 +/- 246 pg/ml in C5d and 756 +/- 232 pg/ml in C5-sufficient, p = 0.003. Conclusion These data demonstrate that C5-deficient mice show enhanced AHR due to increased production of cysteinyl-leukotrienes.http://deepblue.lib.umich.edu/bitstream/2027.42/116863/1/12931_2006_Article_520.pd

Kinetics of TNF, IL-6, and IL-8 gene expression in LPS-stimulated human whole blood

While the production of tumor necrosis factor (TNF) and interleukin-6 (IL-6) in septic shock and other inflammatory states is well established, the role of interleukin-8 (IL-8), a recently described neutrophil chemoattractant and activator, has yet to be fully elucidated. Using lipopolysaccharide (LPS)-stimulated human whole blood as an ex vivo model of sepsis, the kinetics of messenger RNA (mRNA) up-regulation and protein release of these cytokines were examined. Two waves of cytokine gene activation were documented. TNF and IL-6 were induced in the first wave with mRNA levels peaking between 2-4 hours and then rapidly declining. TNF and IL-6 protein peaked at 4-6 hours and then stabilized. IL-8 mRNA and protein were induced in the first wave, reached a plateau between 6-12 hours, and rose again in a second wave which continued to escalate until the end of the 24 hour study. These data demonstrate the complex patterns of cytokine gene expression and suggest that production of early mediators may augment continued expression of IL-8 to recruit and retain neutrophils at a site of inflammation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29503/1/0000589.pd

Reproducibility of a novel model of murine asthma-like pulmonary inflammation

Sensitization to cockroach allergens (CRA) has been implicated as a major cause of asthma, especially among inner-city populations. Endotoxin from Gram-negative bacteria has also been investigated for its role in attenuating or exacerbating the asthmatic response. We have created a novel model utilizing house dust extract (HDE) containing high levels of both CRA and endotoxin to induce pulmonary inflammation (PI) and airway hyperresponsiveness (AHR). A potential drawback of this model is that the HDE is in limited supply and preparation of new HDE will not contain the exact components of the HDE used to define our model system. The present study involved testing HDEs collected from various homes for their ability to cause PI and AHR. Dust collected from five homes was extracted in phosphate buffered saline overnight. The levels of CRA and endotoxin in the supernatants varied from 7·1 to 49·5 mg/ml of CRA and 1·7–6  µ g/ml of endotoxin in the HDEs. Following immunization and two pulmonary exposures to HDE all five HDEs induced AHR, PI and plasma IgE levels substantially higher than normal mice. This study shows that HDE containing high levels of cockroach allergens and endotoxin collected from different sources can induce an asthma-like response in our murine model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75467/1/j.1365-2249.2004.02461.x.pd