Background— Increased production of reactive oxygen species (ROSs) by angiotensin II (Ang II) is involved in the initiation and progression of cardiovascular diseases. NADPH oxidase is a major source of superoxide generated in vascular tissues. Although Nox1 has been identified in vascular smooth muscle cells as a new homolog of gp91phox (Nox2), a catalytic subunit of NADPH oxidase, the pathophysiological function of Nox1-derived ROSs has not been fully elucidated. To clarify the role of Nox1 in Ang II–mediated hypertension, we generated Nox1-deficient ( −/Y ) mice. Methods and Results— No difference in the baseline blood pressure was observed between Nox1 +/Y and Nox1 −/Y . Infusion of Ang II induced a significant increase in mean blood pressure, accompanied by augmented expression of Nox1 mRNA and superoxide production in the aorta of Nox1 +/Y , whereas the elevation in blood pressure and production of superoxide were significantly blunted in Nox1 −/Y . Conversely, the infusion of pressor as well as subpressor doses of Ang II did elicit marked hypertrophy in the thoracic aorta of Nox1 −/Y similar to Nox1 +/Y . Administration of a nitric oxide synthase inhibitor (L-NAME) to Nox1 +/Y did not affect the Ang II–mediated increase in blood pressure, but it abolished the suppressed pressor response to Ang II in Nox1 −/Y . Finally, endothelium-dependent relaxation and the level of cGMP in the isolated aorta were preserved in Nox1 −/Y infused with Ang II. Conclusions— A pivotal role for ROSs derived from Nox1/NADPH oxidase was suggested in the pressor response to Ang II by reducing the bioavailability of nitric oxide.

Transgenic mice expressing the mouse interleukin 33 (IL-33) gene driven by a keratin 14 promoter were generated. The skin-selective expression of the IL-33 gene was enhanced, and intense immunofluorescence for IL-33 was evident in the nuclei of the epidermis. Spontaneous itchy dermatitis developed in those mice at 6-8 wk of age in specific pathogen-free conditions. In the lesional skin, the epidermis was thickened and the eosinophils were infiltrated with increased expression of the eosinophil peroxidase and major basic protein genes. Mast cells were also abundant there, and blood histamine and total IgE levels were high. Those phenotypes closely resemble the features of atopic dermatitis. In peripheral blood and lesional skin, IL-5, IL-13, regulated upon activation, normally Texpressed, and presumably secreted (RANTES)/CCL5, and Eotaxin 1/CCL11 were increased, whereas TNF-α, IFN-γ, and thymic stromal lymphopoietin (TSLP) were unaltered. Furthermore, the proportion of group 2 innate lymphoid cells (ILC2s), which produce IL-5, were significantly increased in the lesional skin, peripheral blood, and regional lymph nodes. The dermatitis with eosinophil infiltration was improved by the administration of an anti-IL-5 antibody. These results suggest that the expression of IL-33 in the skin activates an immune response involving ILC2 and that this process might play a crucial role in the pathogenesis of allergic inflammation that is characteristic of atopic dermatitis.Atopy | natural helper cells | nuocytes

The stratum corneum of the skin serves as an effective barrier for maintenance of the internal milieu against the external environment. At the cell periphery of the stratum corneum is the cell envelope, a highly insoluble membranous structure composed of precursor proteins crosslinked by -(␥-glutamyl)lysine bonds. Transglutaminase 1 (TGase 1; keratinocyte TGase), a membrane-bound isozyme of the TGase family, has been proposed to catalyze this process of assembly. Deficient cross-linking of the cell envelope in some patients with the autosomal recessive skin disorder lamellar ichthyosis (LI) and several mutations of the TGase 1 gene that have been identified in families with LI suggest the importance of this gene in production of the cell envelope. In this study, we generated mice lacking the TGase 1 gene, and we report that they have erythrodermic skin with abnormal keratinization. In their stratum corneum, degradation of nuclei and keratohyalin F-granules was incomplete and cell envelope assembly was defective. The skin barrier function of TGase 1-null mice was markedly impaired, and these mice died within 4-5 h after birth. These results clearly demonstrate that the TGase 1 gene is essential to the development and maturation of the stratum corneum and to adaptation to the environment after birth. Thus, these TGase 1 knockout mice may be a useful model for severe cases of LI.

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