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

Kenyon NJ, Torday JS, Rehan VK. PPAR␥ agonist rosiglitazone prevents perinatal nicotine exposure-induced asthma in rat offspring. Am J Physiol Lung Cell Mol Physiol 300: L710 -L717, 2011. First published February 25, 2011 doi:10.1152/ajplung.00337.2010.-Perinatal exposure to maternal smoke is associated with adverse pulmonary effects, including reduced lung function and increased incidence of asthma. However, the mechanisms underlying these effects are unknown, and there is no effective preventive and/or therapeutic intervention. Recently, we suggested that downregulation of homeostatic mesenchymal peroxisome proliferator-activated receptor-␥ (PPAR␥) signaling following in utero nicotine exposure might contribute to chronic lung diseases such as asthma. We used an in vivo rat model to determine the effect of perinatal nicotine exposure on 1) offspring pulmonary function, 2) mesenchymal markers of airway contractility in trachea and lung tissue, and 3) whether administration of a PPAR␥ agonist, rosiglitazone (RGZ), blocks the molecular and functional effects of perinatal nicotine exposure on offspring lung. Pregnant SpragueDawley rat dams received placebo, nicotine, or nicotine ϩ RGZ daily from embryonic day 6 until postnatal day 21, when respiratory system resistance, compliance, tracheal contractility, and the expression of markers of pulmonary contractility were determined. A significant increase in resistance and a decrease in compliance under basal conditions, with more pronounced changes following methacholine challenge, were observed with perinatal nicotine exposure compared with control. Tracheal constriction response and expression of mesenchymal markers of airway contractility were also significantly increased following perinatal nicotine exposure. Concomitant treatment with RGZ completely blocked the nicotine-induced alterations in pulmonary function, as well as the markers of airway contractility, at proximal and distal airway levels. These data suggest that perinatal smoke exposure-induced asthma can be effectively blocked by PPAR␥ agonists.pregnancy; peroxisome proliferator-activated receptor-␥; smoke THERE IS STRONG EPIDEMIOLOGICAL and experimental evidence that perinatal exposure to maternal smoking results in detrimental long-term effects on lung growth and function, including significant suppression of alveolarization and increased predisposition to asthma in the offspring (2, 4 -6, 9, 13-15, 17, 27, 30, 42, 44, 45, 49). Since the mechanisms underlying these adverse pulmonary effects remain incompletely understood, there are no effective preventive or therapeutic interventions. Recently, on the basis of in vitro and in vivo studies from our laboratory, we suggested that downregulation of homeostatic lung mesenchymal peroxisome proliferator-activated receptor-␥ (PPAR␥) signaling might be a key contributor to chronic lung diseases such as bronchopulmonary dysplasia and asthma (23,34,36,37,48). We previously showed that in vitro and in vivo nicotine exposures result in the downregulation of pulmo...

Arginase1 and nitric oxide synthase2 (NOS2) utilize L-arginine as a substrate, with both enzymes expressed at high levels in the asthmatic lung. Inhibition of arginase in ovalbumin-exposed C57BL/6 mice with the transition state inhibitor Nω-hydroxy-nor-L-arginine (nor-NOHA) significantly increased total L-arginine content in the airway compartment. We hypothesized that such an increase in L-arginine content would increase the amount of nitric oxide (NO) being produced in the airways and thereby decrease airway hyper-reactivity and eosinophilic influx. We further hypothesized that despite arginase inhibition, NOS2 knockout (NOS2−/−) mice would be unable to up-regulate NO production in response to allergen exposure and would demonstrate higher amounts of airway hyper-reactivity and eosinophilia under conditions of arginase inhibition than C57BL/6 animals. We found that administration of nor-NOHA significantly decreased airway hyper-reactivity and eosinophilic airway inflammation in ovalbumin-exposed C57BL/6 mice, but these parameters were unchanged in ovalbumin-exposed NOS2−/− mice. Arginase1 protein content was increased in mice exposed to ovalbumin, an effect that was reversed upon nor-NOHA treatment in C57BL/6 mice. Arginase1 protein content in the airway compartment directly correlated with the degree of airway hyper-reactivity in all treatment groups. NOS2−/− mice had a significantly greater arginase1 and arginase2 concentrations compared to their respective C57BL/6 groups, indicating that inhibition of arginase may be dependent upon NOS2 expression. Arginase1 and 2 content were not affected by nor-NOHA administration in the NOS2−/− mice. We conclude that L-arginine metabolism plays an important role in the development of airway hyper-reactivity and eosinophilic airway inflammation. Inhibition of arginase early in the allergic inflammatory response decreases the severity of the chronic inflammatory phenotype. These effects appear to be attributable to NOS2, which is a major source of NO production in the inflamed airway, although arginase inhibition may also be affecting the turnover of arginine by the other NOS isoforms, NOS1 and NOS3. The increased L-arginine content in the airway compartment of mice treated with nor-NOHA may directly or indirectly, through NOS2, control arginase expression both in response to OVA exposure and at a basal level.

Inhibition of the α4 subunit of both the α4β1 and α4β7 integrins has shown promise in decreasing airway inflammation and airway hyperresponsiveness in various animal models. We hypothesized that a novel, high-affinity α4β1 antagonist (LLP2A) would decrease the migration of eosinophils to the lung and ameliorate the airway hyperresponsiveness in a mouse model of ovalbumin-induced airway inflammation. To test this hypothesis, we administered LLP2A, or scrambled LLP2A (a negative control), prior to exposure of sensitized BALB/c mice to ovalbumin aerosol. We can partially prevent, or reverse, the airway inflammatory response, but not airways hyperresponsiveness, by treatment of mice with LLP2A, a synthetic peptidomimetic α4β1 antagonist LLP2A. Specifically engineered, PEGylated (PEG) formulations of this antagonist further reduce the airway inflammatory response to ovalbumin lbumin, presumably by improving the circulating half-life of the drug.

l-Arginine, the amino acid substrate for nitric oxide synthase, has been tested as a therapeutic intervention in a variety of chronic diseases and is commonly used as a nutritional supplement. In this study, we hypothesized that a subset of moderate to severe persistent asthma patients would benefit from supplementation with l-arginine by transiently increasing nitric oxide levels, resulting in bronchodilation and a reduction in inflammation. The pilot study consisted of a 3 month randomized, double-blind, placebo-controlled trial of l-arginine (0.05 g/kg twice daily) in patients with moderate to severe asthma. We measured spirometry, exhaled breath nitric oxide, serum arginine metabolites, questionnaire scores, daily medication use and PEFR with the primary endpoint being the number of minor exacerbations at three months. Interim analysis of the 20 subjects showed no difference in the number of exacerbations, exhaled nitric oxide levels or lung function between groups, though participants in the l-arginine group had higher serum l-arginine at day 60 (2.0 ± 0.6 × 10−3 vs. 1.1 ± 0.2 × 10−3 μmol/L, p < 0.05), ornithine at day 30 (2.4 ± 0.9 vs. 1.2 ± 0.3 μmol/L serum, p < 0.05) and ADMA at day 30 (6.0 ± 1.5 × 10−1 vs. 2.6 ± 0.6 × 10−1 μmol/L serum, p < 0.05) on average compared to the placebo group. The study was terminated prematurely. Supplementing asthma subjects with l-arginine increases plasma levels; whether subgroups might benefit from such supplementation requires further study.