Lungs Of Strains Research Articles

Genetic variability of T cell responses in hypersensitivity pneumonitis identified using the BXD genetic reference panel.

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that may progress to fibrosis and significant risk of death. HP develops following repeated exposures to inhaled environmental antigens; however, only a fraction of the exposed population develops the disease, suggesting that host genetics contribute to disease susceptibility. We used the BXD family of mice with the Saccharopolyspora rectivirgula (SR) model of HP to investigate the role of genetics in susceptibility to HP. The BXD family is derived from a B6 mother and a D2 father and has been used to map susceptibility loci to numerous diseases. B6, D2, and BXD progeny strains were exposed to SR for 3 wk, and the development of HP was monitored. The B6 and D2 strains developed alveolitis; however, the cellular composition was neutrophilic in the D2 strain and more lymphocytic in the B6 strain. Hematoxylin-eosin staining of lung sections revealed lymphoid aggregates in B6 lungs, whereas D2 lungs exhibited a neutrophilic infiltration. Twenty-eight BXD strains of mice were tested, and the results reveal significant heritable variation for numbers of CD4+ or CD8+ T cells in the air spaces. There was significant genetic variability for lymphoid aggregates and alveolar wall thickening. We mapped a significant quantitative trait locus (QTL) on chromosome 18 for CD8+CD69+ T cells that includes cadherin 2 (Cdh2), an excellent candidate gene associated with epithelial-mesenchymal transition, which is upregulated in lungs of strains with HP. These results demonstrate that the BXD family is a valuable and translationally relevant model to identify genes contributing to HP and to devise early and effective interventions.

Expression of cyclin D1/2 in the lungs of strain A/J mice fed chemopreventive agents.

Male strain A mice were fed a diet containing chemopreventive agents. After 1 and 3 weeks on the diets, lung nuclear fractions were examined for expression of cyclin D1/2 with western blot analysis. In animals fed a diet containing a mixture of myoinositol and dexamethasone, a treatment found previously to be effective in preventing the development of tobacco smoke-induced lung tumors in A/J mice, cyclin D1/2 expression was reduced to 30-40% of control levels. A similar decrease in cyclin D1/2 expression was found when animals were fed either myoinositol or dexamethasone alone. Paradoxically, tobacco smoke by itself had a similar effect on cyclin D1/2 expression. On the other hand, several agents that had been previously found not to be effective against tobacco smoke carcinogenesis [phenethyl isothiocyanate, 1,4-phenylenebis(methylene)selenoisocyanate, N-acetylcysteine, acetylsalicylic acid, D-limonene and beta carotene] did not decrease cyclin D1/2 expression after 1 or 3 weeks of feeding. It was concluded that expression of cyclin D1/2 might be a potentially useful marker in the identification of chemopreventive agents for tobacco smoke and could be of some help in the evaluation of their effects.

Time-Integrated DNA Adduct Levels and Relative Tumorigenic Potencies of Six Polycyclic Aromatic Hydrocarbons in Strain A/J Mouse Lung

Abstract We have investigated the induction of DNA adducts and adenomas in the lungs of strain A/J mice following the i.p. administration of several polycyclic aromatic hydrocarbons (PAH): pyrene, dibenz[a,h]anthracene (DBA), benzo[a]pyrene (B[a]P), benzo[b]fluoranthene (B[b]F), 5-methylchrysene (5-MeC), 3-methylcholanthrene (3-MC), and cyclopenta[cd]pyrene (CPP). All of the PAH induced lung adenomas, with relative tumor potency rankings as a function of administered dose: DBA = 3-MC > 5-MeC > CPP > B[a]P > B[b]F. DNA adducts reached maximal levels between 3 and 7 days after injection, followed by a gradual decrease. The time-integrated DNA adduct level (TIDAL) was calculated by numerically integrating the areas under the adduct persistence curves extrapolated out to 240 days for each PAH at each dose level. Tumorigenic potencies as a function of TIDAL values for 5-MeC, B[a]P, B[b]F, and CPP were all equal, while 3-MC was 2.6-fold more potent and DBA was 25.8-fold more potent.

Benzo[b]fluoranthene: tumorigenicity in strain A/J mouse lungs, DNA adducts and mutations in the Ki-ras oncogene.

The polycyclic aromatic hydrocarbon benzo[b]fluoranthene (B[b]F) is a pervasive constituent of environmental combustion products. We sought to examine the lung tumorigenic activity of B[b]F in strain A/J mice, to study the relationship between formation and decay of B[b]F-DNA adducts and to examine mutations in the Ki-ras proto-oncogene in DNA from B[b]F-induced tumors. Mice were given i.p. injections of 0, 10, 50, 100 or 200 mg/kg body wt and lung adenomas were scored after 8 months. B[b]F induced significant numbers of mouse lung adenomas in a dose-related fashion, with the highest dose (200 mg/kg) yielding 6.95 adenomas/ mouse, with 100% of the mice exhibiting an adenoma. In mice given tricaprylin, the vehicle control, there were 0.60 adenomas/mouse, with 55% of the mice exhibiting an adenoma. Based on dose, B[b]F was less active than benzo[a]pyrene. DNA adducts were analyzed qualitatively and quantitatively by 32P-post-labeling in lungs of strain A/J mice 1, 3, 5, 7, 14 and 21 days after i.p. injection. Maximal levels of adduction occurred 5 days after treatment with the 200 mg/kg dose group, producing 1230 amol B[b]F-DNA adducts/microgram DNA. The major B[b]F-DNA adduct was identified by co-chromatography as trans-9, 10-dihydroxy-anti-11, 12-epoxy-5-hydroxy-9, 10, 11, 12-tetra-hydro-B[b]F-deoxyguanosine. Approximately 86% of the tumors had a mutation in codon 12 of the Ki-ras oncogene, as determined by direct DNA sequencing of PCR-amplified exon 1 and single-stranded conformation polymorphism analysis. Analysis of the Ki-ras mutation spectrum in 25 of 29 B[b]F-induced tumors revealed the predominant mutation to be a G-->T transversion in the first or second base of codon 12, congruous with the DNA adduct data. Our data are consistent with previous reports in mouse skin implicating a phenolic diol epoxide as the proximate carcinogenic form of B[b]F that binds to guanine.

Ki‐ras oncogene mutations in tumors and DNA adducts formed by benz[j]aceanthrylene and benzo[a]pyrene in the lungs of strain A/J mice

Strain A/J mice received intraperitoneal injections of benz[j]aceanthrylene (B[j]A) or benzo[a]pyrene (B[a]P). At 24, 48, and 72 h, lung tissues were removed for analysis of B[a]P- or B[j]A-derived DNA adduct formation during the first 3 d of exposure. One group of mice exposed to these hydrocarbons was kept for 8 mo to determine lung tumor multiplicity, the occurrence of mutations in codons 12 and 61 of the Ki-ras gene in the tumors that arose, the relationship between Ki-ras oncogene mutations in tumors, and the presence and quantity of genomic DNA adducts. The major DNA adduct in the lungs of mice exposed to B[a]P was N2-(10 beta-[+B, 7 alpha, 9 alpha-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene]yl)-deoxyguanosine (BPDE-I-dGuo) arising from bay-region diolepoxide activation of B[a]P and was consistent with the occurrence of tumors with mutations GGT-->TGT (56%), GGT-->GTT (25%), and GGT-->GAT (19%) in codon 12, all involving mutations of a guanine. B[j]A, a demethylated analogue of 3-methylcholanthrene (3-MCA) with an unsaturated cyclopenta ring, produced 16-to 60-fold more tumors at equivalent doses than did B[a]P; the mutations in tumors were GGT-->TGT (4%), GGT-->GTT (30%), and GGT-->CGT (65%). Analysis of adduction patterns in DNA suggested that B[j]A was activated to form DNA-binding derivatives in A/J mouse lungs primarily at the cyclopenta ring even though B[j]A contains a bay region. As reported in the published literature, the mutation spectrum induced by 3-MCA in Ki-ras codon 12 of mouse cells is similar to that of B[a]P but not to that of its close relative B[j]A. In contrast to B[j]A, 3-MCA is activated mostly via a bay-region diol-epoxide since its cyclopenta ring is saturated and not easily epoxidates. Therefore, we propose that the GGT-->CGT mutations produced by B[j]A in Ki-ras codon 12 were mostly the result of cyclopenta-ring-derived adducts.

Synthesis of Ellagic Acid O-Alkyl Derivatives and Isolation of Ellagic Acid as a Tetrahexanoyl Derivative from Fragaria ananassa

Ellagic acid [1] is a gallic acid dimer that occurs in plants, fruits, and nuts, either in its free form, or in a series of ellagitannins, or as a glucoside. It has been shown to inhibit cancer induced by several types of chemical carcinogens including polycyclic aromatic hydrocarbons, N-nitrosamines, aflatoxin, and aromatic amines. It has been extracted from a number of fruits, including strawberries; however, its presence in the extracts was determined only by hplc connected with a diode array detector. In the present report, ellagic acid was isolated as a tetrahexanoyl derivative 2 from Fragaria ananassa and identified by 13C and 1H nmr and ms. The 13C-nmr shifts of the aromatic carbons adjacent to a hexanoyloxy group were assigned using two new synthetic model compounds: 3,3'-dihexanoyloxydiphenic-2,2',6,6'-dilactone [3] and 4,4'-dihexanoyloxydiphenic-2,2',6,6'-dilactone [4]. Two new derivatives of ellagic acid [1],3,3'-di-beta-D-glucopyranosylellagic acid decaacetate [5] and 3,3'-di-n-octyl-4,4'-dihexanoylellagic acid [7], were also synthesized. Both derivatives were less effective as inhibitors of benzo[a]pyrene tumorigenesis in the lungs of strain A/J mice than ellagic acid.

Effects of calcium(II) and magnesium(II) on nickel(II) uptake and stimulation of thymidine incorporation into DNA in the lungs of strain A mice.

The effect of calcium(II)acetate (CaAcet) and magnesium(II) acetate (MgAcet) on nickel(II) uptake in the lungs of strain A mice and on the nickel(II)-induced changes in the pulmonary DNA synthesis were studied in order to elucidate the mechanism(s) of inhibitory action of CaAcet and MgAcet upon nickel(II) tumorigenesis. Male strain A mice received a total of three i.p. injections, one every second day, of nickel(II)acetate (NiAcet), CaAcet, or MgAcet alone, or combined in a common solution. The single doses were 43 mumol NiAcet and 430 mumol CaAcet or MgAcet/kg body weight. To determine the uptake of nickel(II) by the lungs and pulmonary subcellular fractions, NiAcet labelled with 63Ni was used and the mice were sacrificed 2 days after the last injection. The [14C]thymidine uptake by the pulmonary DNA was determined at 6 h and 1-12 days after the last injection of metal salt(s). CaAcet increased nickel(II) uptake by the pulmonary cell mitochondria by 30%, microsomes by 40% and cytosol by 15%, compared with mice given NiAcet alone; nuclear nickel(II) levels were not affected. MgAcet decreased nickel(II) uptake in the nuclei by 15% and cytosol by 25%, and had no effect on the uptake by mitochondria and microsomes. A significant decrease of thymidine incorporation into pulmonary DNA was produced by NiAcet alone and CaAcet alone at 6 h to 2 days after the injection, followed by a single round of increased thymidine incorporation between days 3 and 6 after the injection. The mixture of NiAcet and CaAcet significantly increased the thymidine incorporation into pulmonary DNA without its prodromal decrease. MgAcet alone had no influence on the uptake of thymidine into DNA, except for a slight increase on day 5; but administered together with NiAcet it completely prevented the effects of nickel(II) upon thymidine incorporation. The results provide evidence that MgAcet, but not CaAcet, may inhibit tumorigenicity of NiAcet in the lungs of strain A mice by suppressing uptake of nickel(II) by the pulmonary cell nuclei and soluble fractions, and by preventing the effects of NiAcet on pulmonary DNA synthesis.

Carcinogenic activity of acrylamide in the skin and lung of Swiss-ICR mice

Doses of acrylamide ranging from 12.5 to 50 mg/kg were administered orally to female ICR-Swiss mice over 3 days for each of 2 weeks (total doses of 75, 150 and 300 mg/kg). Two weeks later some of the animals were started on a promotion schedule involving the application of 2.5 μg TPA/mouse 3 times weekly. Development of tumors was observed weekly in the skin, and in the lungs at 1 year. Acrylamide was found to initiate squamous cell adenoma and carcinomas in the skin and increased the yield of adenomas and carcinomas in the lung. Skin tumor development was dependent upon 12- O-tetradecanoylphorbol-13-acetate (TPA) promotion whereas lung tumor induction was not. These data extend previous observations of carcinogenic activity of acrylamide in the skin of SENCAR mice and lungs of strain A/J mice to a third strain of mouse, the ICR-Swiss.

Sensitivity of mouse, rat, and human embryonic lungs to the action of nitrosomethylurea in organ culture

In response to the direct action of nitrosomethylurea (NMU) in a concentration of 0.05 mg/ml on organ cultures of embryonic lungs of strain A mice, Wistar rats, and man, a varied degree of degenerative changes and hyperplastic proliferation of the epithelium developed in the cultures. In the early stages of the experiment the toxic effect of the cultures predominated. Tissue of rat embryonic lungs was most sensitive to the toxic action of NMU, mouse lung tissue least sensitive. The frequency of hyperplastic proliferation, on the other hand, was highest in cultures of mouse lungs and lowest in cultures of rat lungs. During culture the sensitivity of the human and rodent embryonic lungs to the toxic action of NMU decreased when the substance was repeatedly added to the nutrient medium. Meanwhile an increase in the survival of the experimental cultures was observed compared with the intact control.

Histochemical study of induced gastrointestinal tract tumors in strain A/jax (lung tumor susceptible) mice.

Tumors were induced in the small intestine, forestomach, and lungs of strain A/jax mice by feeding olive oil emulsions containing 20-methylcholanthrene. Histochemical methods were used to determine the occurrence and distribution of acid and alkaline phosphatase in the tissues of the mice. The tumors generally showed a complete absence of alkaline phosphatase and widely varying quantities of acid phosphatase in the cytoplasm of the individual cells. Tumors of the small intestine and forestomach showed a high concentration of alkaline phosphatase in the submucosal zone immediately beneath the neoplasm. No enzyme changes from normal were detected in lesions considered histologically to be premalignant. Some groups of mice were fed iron choline citrate or ethylenediamine tetraacetic acid, tetrasodium salt in addition to 20-methylcholanthrene. These substances produced no effect on the rate of growth or numbers of tumors induced, nor on the acid and alkaline phosphatase reactions.