trichostatin-a and Hypersensitivity

Eosinophils are one of the cells that play a critical role in the pathogenesis of allergic diseases. The increase in the number of eosinophils in such diseases is regulated by interleukin-5 (IL-5). The author have prepared recombinant rat IL-5 using a baculovirus expression system and examined its biological activities in rat eosinophils. It was demonstrated that recombinant rat IL-5 prolongs the survival of mature eosinophils and differentiates immature eosinophils into mature eosinophils, suggesting that rat IL-5 is a factor for eosinophilia in rats. Recombinant rat eosinophil-associated ribonuclease (Ear)-1 and Ear-2 were also prepared. Eosinophil granule proteins are thought to cause tissue damage due to their cytotoxic activity, but using recombinant rat Ear-1 and Ear-2, it was found that rat Ear-1 and Ear-2 have strong RNase A activity and bactericidal activity, suggesting that these proteins play critical roles in host defense. Finally, the important role of acetylation of histones was clarified in the differentiation of HL-60 clone 15 cells into eosinophils using the histone deacetylase inhibitors sodium n-butyrate, apicidin, and trichostatin A. These findings would be useful for further investigations of the role of eosinophils in allergic inflammation.

Topics: Acetylation; Animals; Butyrates; Cell Differentiation; Cell Division; Enzyme Inhibitors; Eosinophil Cationic Protein; Eosinophil Granule Proteins; Eosinophils; Histone Deacetylase Inhibitors; Histones; HL-60 Cells; Humans; Hydroxamic Acids; Hypersensitivity; Inflammation; Interleukin-5; Peptides, Cyclic; Rats; Recombinant Proteins

The disruption of epithelial barrier integrity is an important factor in the pathogenesis of various immune disorders. However, the restitution of the compromised barrier functions is difficult. This study investigates the regulation of TWIK-related potassium channel-1 (Trek1) in the restitution of intestinal epithelial barrier functions. The human colon epithelial cell line T84 was cultured in monolayers and used to observe epithelial barrier functions in vitro. An intestinal allergy mouse model was created. Cytokine levels were determined by enzyme-linked immunosorbent assay and western blotting. The results showed that Trek1 deficiency induced T84 monolayer barrier disruption. Allergic responses markedly suppressed the expression of Trek1 in the intestinal epithelia via activating the mitogen-activated protein kinase pathways and increasing the expression of histone deacetylase-1. The inhibition of histone deacetylase-1 by sodium butyrate or the administration of a butyrate-producing probiotic (Clostridium butyricum) restored the intestinal epithelial barrier functions and markedly enhanced the effect of antigen-specific immunotherapy. The data suggest that Trek1 is required for the maintenance of intestinal epithelial barrier integrity. Allergic responses induce an insufficiency of Trek1 expression in the intestinal epithelia. Trek1 expression facilitates the restoration of intestinal epithelial barrier functions in an allergic environment.

Topics: Animals; Butyric Acid; Cell Line; Clostridium butyricum; Cytokines; Eosinophils; Epithelial Cells; Gene Expression Regulation; Histone Deacetylase 1; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Hypersensitivity; Intestinal Mucosa; Mast Cells; Mice; Mice, Inbred BALB C; Mitogen-Activated Protein Kinases; Ovalbumin; Potassium Channels, Tandem Pore Domain; Probiotics; Signal Transduction

UV-induced DNA damage causes repression of RNA synthesis. Following the removal of DNA lesions, transcription recovery operates through a process that is not understood yet. Here we show that knocking-out of the histone methyltransferase DOT1L in mouse embryonic fibroblasts (MEF(DOT1L)) leads to a UV hypersensitivity coupled to a deficient recovery of transcription initiation after UV irradiation. However, DOT1L is not implicated in the removal of the UV-induced DNA damage by the nucleotide excision repair pathway. Using FRAP and ChIP experiments we established that DOT1L promotes the formation of the pre-initiation complex on the promoters of UV-repressed genes and the appearance of transcriptionally active chromatin marks. Treatment with Trichostatin A, relaxing chromatin, recovers both transcription initiation and UV-survival. Our data suggest that DOT1L secures an open chromatin structure in order to reactivate RNA Pol II transcription initiation after a genotoxic attack.

Topics: Animals; Chromatin; DNA Damage; DNA Repair; Gene Expression Regulation; Histone-Lysine N-Methyltransferase; Hydroxamic Acids; Hypersensitivity; Methyltransferases; Mice; Mice, Knockout; RNA Polymerase II; Transcriptional Activation; Ultraviolet Rays

Damage to airway epithelium is followed by deposition of extracellular matrix (ECM) and migration of adjacent epithelial cells. We have shown that epithelial cells from children with asthma fail to heal a wound in vitro.. To determine whether dysregulated ECM production by the epithelium plays a role in aberrant repair in asthma.. Airway epithelial cells (AEC) from children with asthma (n = 36), healthy atopic control subjects (n = 23), and healthy nonatopic control subjects (n = 53) were investigated by microarray, gene expression and silencing, transcript regulation analysis, and ability to close mechanical wounds.. Time to repair a mechanical wound in vitro by AEC from healthy and atopic children was not significantly different and both were faster than AEC from children with asthma. Microarray analysis revealed differential expression of multiple gene sets associated with repair and remodeling in asthmatic AEC. Fibronectin (FN) was the only ECM component whose expression was significantly lower in asthmatic AEC. Expression differences were verified by quantitative polymerase chain reaction and ELISA, and reduced FN expression persisted in asthmatic cells over passage. Silencing of FN expression in nonasthmatic AEC inhibited wound repair, whereas addition of FN to asthmatic AEC restored reparative capacity. Asthmatic AEC failed to synthesize FN in response to wounding or cytokine/growth factor stimulation. Exposure to 5', 2'deoxyazacytidine had no effect on FN expression and subsequent analysis of the FN promoter did not show evidence of DNA methylation.. These data show that the reduced capacity of asthmatic epithelial cells to secrete FN is an important contributor to the dysregulated AEC repair observed in these cells.

Topics: Adolescent; Asthma; Azacitidine; Cells, Cultured; Child; Child, Preschool; Cycloheximide; Dexamethasone; DNA Methylation; Enzyme-Linked Immunosorbent Assay; Epithelial Cells; Extracellular Matrix; Fibronectins; Homocystine; Humans; Hydroxamic Acids; Hypersensitivity; Microarray Analysis; Respiratory Mucosa; Tetradecanoylphorbol Acetate; Transforming Growth Factor beta1