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Nitric oxide plays a critical role in many physiological and physiopathological processes in the lung. Changes in the NO/NOS (Nitric Oxide/Nitric Oxide Synthase) system after hypoxia situations remain controversial in this organ, so that the aim of this work is to perform a complete study of this system in the hypoxic lung after different reoxygenation times ranging from 0 h to 5 days posthypoxia. This is a novel follow-up study carried out in Wistar rats submitted for 30 min to acute hypobaric hypoxia. We measured endothelial and inducible NOS (eNOS, iNOS) mRNA and protein expression, location, and in situ NOS activity as well as nitrated protein expression and location. In addition, NO levels were indirectly quantified (NOx) as well as the apoptosis level. Results showed an increase in eNOS mRNA, protein, activity as well as eNOS positive immunostaining at 0 h posthypoxia, coinciding with raised NOx levels. Contrary, iNOS, nitrated protein expression and apoptosis level augmented during the final reoxygenation times. The lung NO/NOS system provokes two responses to the hypoxia/reoxygenation processes: (i) eNOS is responsible of the immediate response, producing NO, which causes vasodilation and bronchodilation, and (ii) iNOS is related to the second late response, which seems to be involved in some of the deleterious consequences that hypoxia induces in the lung.

BackgroundThe cerebellum is the neural structure with the highest levels of nitric oxide, a neurotransmitter that has been proposed to play a key role in the brain aging, although knowledge concerning its contribution to cerebellar senescence is still unclear, due mainly to absence of integrative studies that jointly evaluate the main factors involved in its cell production and function. Consequently, in the present study, we investigate the expression, location, and activity of nitric oxide synthase isoenzymes; the protein nitration; and the production of nitric oxide in the cerebellum of adult and old rats.ResultsOur results show no variation in the expression of nitric oxide synthase isoforms with aging, although, we have detected some changes in the cellular distribution pattern of the inducible isoform particularly in the cerebellar nuclei. There is also an increase in nitric oxide synthase activity, as well as greater protein-nitration levels, and maintenance of nitrogen oxides (NOx) levels in the senescent cerebellum.ConclusionsThe nitric oxide/nitric oxide syntahses system suffers from a number of changes, mainly in the inducible nitric oxide synthase distribution and in overall nitric oxide synthases activity in the senescent cerebellum, which result in an increase of the protein nitration. These changes might be related to the oxidative damage detected with aging in the cerebellum.

Background: Allergic sensitization might be influenced by the lipids present in allergens, which can be recognized by natural killer T (NKT) cells on antigen-presenting cells (APCs). The aim of this study wasto analyze the effect of olive pollen lipids in human APCs, including monocytes as well as monocyte-derived macrophages (Mϕ) and dendritic cells (DCs). Methods: Lipids were extracted from olive (Olea europaea) pollen grains. Invariant (i)NKT cells, monocytes, Mϕ, and DCs were obtained from buffy coats of healthy blood donors, and their cell phenotype was determined by flow cytometry. iNKT cytotoxicity was measured using a lactate dehydrogenase assay. Gene expression of CD1A and CD1D was performed by RT-PCR, and the production of IL-6, IL-10, IL-12, and TNF-α cytokines by monocytes, Mϕ, and DCs was measured by ELISA. Results: Our results showed that monocytes and monocyte-derived Mϕ treated with olive pollen lipids strongly activate iNKT cells. We observed several phenotypic modifications in the APCs upon exposure to pollen-derived lipids. Both Mϕ and monocytes treated with olive pollen lipids showed an increase in CD1D gene expression, whereas upregulation of cell surface CD1d protein occurred only in Mϕ. Furthermore, DCs differentiated in the presence of human serum enhance their surface CD1d expression when exposed to olive pollen lipids. Finally, olive pollen lipids were able to stimulate the production of IL-6 but downregulated the production of lipopolysaccharide- induced IL-10 by Mϕ. Conclusions: Olive pollen lipids alter the phenotype of monocytes, Mϕ, and DCs, resulting in the activation of NKT cells, which have the potential to influence allergic immune responses.

Background:Salsola kali is an Amaranthaceae weed with important repercussions for pollinosis in temperate areas. Ole e 1-like members are relevant allergens in pollen from different species. We aimed to characterize and produce as recombinant allergen S. kali Ole e 1-like protein. Methods: The natural allergen was purified at homogeneity after three chromatographic steps. Specific cDNA was sequenced and expressed in Pichia pastoris yeast. Structural relationships of natural and recombinant forms were carried out by 2D electrophoresis and spectroscopic analyses. Its immunological relevance was analyzed by ELISA and immunoblotting using an IgG antiserum and monoclonal antibodies specific to Ole e 1, as well as sera from 57 allergic patients recruited from two Spanish regions where this pollinosis is frequent. Results: The purified allergen, Sal k 5, is an acidic glycoprotein of 151 amino acid residues and 17,628 Da of molecular mass. Its amino acid sequence exhibits 68 and 32% identity with the allergens of Che a 1 and Ole e 1, respectively. The recombinant protein was correctly processed and its structural and immunologic equivalence to the natural form was proven. A sensitization frequency between 30 and 40% was observed in pollinic patients from the center and east coast of Spain. Conclusions: Sal k 5 is a member of the Ole e 1-like protein family which can be considered an important allergen from S. kali. Its inclusion in diagnosis protocols would allow the accurate defining of patients allergic to this pollen.