Defective repair of radiation-induced DNA damage is complemented by a CHORI-230-65K18 BAC clone on rat chromosome 4

AbstractThe Long Evans cinnamon (LEC) rat is highly susceptible to X-irradiation due to defective DNA repair and is thus a model for hepatocellular carcinogenesis. We constructed a bacterial artificial chromosome (BAC) contig of rat chromosome 4 completely covering the region associated with radiation susceptibility. We used transient and stable transfections to demonstrate that defective DNA repair in LEC cells is fully complemented by a 200-kb BAC, CHORI-230-65K18. Further analysis showed that the region associated with radiation susceptibility is located in a 128,543-bp region of 65K18 that includes the known gene Rpn1. However, neither knockdown nor overexpression of Rpn1 indicated that this gene is associated with radiation susceptibility. We also mapped three ESTs (TC523872, TC533727, and CB607546) in the 128,543-bp region, suggesting that 65K18 contains an unknown gene associated with X-ray susceptibility in the LEC rat

Induction of human regulatory innate lymphoid cells from group 2 innate lymphoid cells by retinoic acid

BACKGROUND: Group 2 innate lymphoid cells (ILC2s) play critical roles in induction and exacerbation of allergic airway inflammation. Thus, clarification of the mechanisms that underlie the regulation of ILC2 activation has received significant attention. Although ILCs are divided into three major subsets that mirror helper effector T-cell subsets, counterpart subsets of regulatory T (Treg) cells have not been well characterized. OBJECTIVE: We sought to determine the factors that induce regulatory ILCs (ILCregs). METHODS: IL-10+ ILCregs induced from ILC2s by retinoic acid (RA) were analyzed using RNA-sequencing and flow cytometry. ILCregs were evaluated in human nasal tissues from healthy individuals and patients with chronic rhinosinusitis with nasal polyp (CRSwNP), and in lung tissues from house dust mite (HDM)- or saline-treated mice. RESULTS: RA induced IL-10 secretion by human ILC2s, but not type-2 cytokines. IL-10+ ILCregs, converted from ILC2s by RA stimulation, expressed a Treg-like signature with the expression of IL-10, CTLA-4 and CD25, with down regulated effector type 2-related markers such as CRTH-2 and ST2, and suppressed activation of CD4+ T cells and ILC2s. ILCregs were rarely detected in human nasal tissue from healthy individuals or lung tissues from saline-treated mice, but were increased in nasal tissues from patients with CRSwNP and in lung tissues from HDM-treated mice. Enzymes for RA synthesis were up-regulated in airway epithelial cells during type-2 inflammation in vivo and by IL-13 in vitro. CONCLUSION: We have identified a unique immune regulatory and anti-inflammatory pathway by which RA converts ILC2s to ILCregs. Interactions between airway epithelial cells and ILC2s play an important roles in the generation of ILCregs

Predictive value of IgE/IgG₄ antibody ratio in children with egg allergy

Abstract Background The aim of this study was to investigate the role of specific IgG4 antibodies to hen’s egg white and determine their utility as a marker for the outcome of oral challenge test in children sensitized to hen’s egg Methods The hen’s egg oral food challenge test was performed in 105 sensitized children without atopic dermatitis, and the titers of egg white-specific immunoglobulin G4 (IgG4) and immunoglobulin E (IgE) antibodies were measured. To set the cut-off values of IgG4, IgE, and the IgE/IgG4 ratio for predicting positive results in oral challenges, receiver operating characteristic curves were plotted and the area under the curves (AUC) were calculated. Results Sixty-four of 105 oral challenges with whole eggs were assessed as positive. The AUC for IgE, IgG4, and IgE/IgG4 for the prediction of positive results were 0.609, 0.724, and 0.847, respectively. Thus, the IgE/IgG4 ratio generated significantly higher specificity, sensitivity, positive predictive value (%), and negative predictive value (%) than the individual IgE and IgG4. The negative predictive value of the IgE/IgG4 ratio was 90% at a value of 1. Conclusions We have demonstrated that the egg white-specific serum IgE/IgG4 ratio is important for predicting reactivity to egg during food challenges.</p

Type 2 innate lymphoid cells disrupt bronchial epithelial barrier integrity by targeting tight junctions through IL-13 in asthmatic patients

BACKGROUND Bronchial epithelial barrier leakiness and type 2 innate lymphoid cells (ILC2s) have been separately linked to asthma pathogenesis; however, the influence of ILC2s on the bronchial epithelial barrier has not been investigated previously. OBJECTIVE We investigated the role of ILC2s in the regulation of bronchial epithelial tight junctions (TJs) and barrier function both in bronchial epithelial cells of asthmatic patients and healthy subjects and general innate lymphoid cell- and ILC2-deficient mice. METHODS Cocultures of human ILC2s and bronchial epithelial cells were used to determine transepithelial electrical resistance, paracellular flux, and TJ mRNA and protein expressions. The effect of ILC2s on TJs was examined by using a murine model of IL-33-induced airway inflammation in wild-type, recombination-activating gene 2 (Rag2)-/-, Rag2-/-Il2rg-/-, and Rorasg/sg mice undergoing bone marrow transplantation to analyze the in vivo relevance of barrier disruption by ILC2s. RESULTS ILC2s significantly impaired the epithelial barrier, as demonstrated by reduced transepithelial electrical resistance and increased fluorescein isothiocyanate-dextran permeability in air-liquid interface cultures of human bronchial epithelial cells. This was in parallel to decreased mRNAs and disrupted protein expression of TJ proteins and was restored by neutralization of IL-13. Intranasal administration of recombinant IL-33 to wild-type and Rag2-/- mice lacking T and B cells triggered TJ disruption, whereas Rag2-/-Il2rg-/- and Rorasg/sg mice undergoing bone marrow transplantation that lack ILC2s did not show any barrier leakiness. Direct nasal administration of IL-13 was sufficient to induce deficiency in the TJ barrier in the bronchial epithelium of mice in vivo. CONCLUSION These data highlight an essential mechanism in asthma pathogenesis by demonstrating that ILC2s are responsible for bronchial epithelial TJ barrier leakiness through IL-13