Neutrophil extracellular traps are downregulated by glucocorticosteroids in lungs in an equine model of asthma

Background

Severe neutrophilic asthma is poorly responsive to glucocorticosteroids (GC). Neutrophil extracellular traps (NETs) within the lungs have been associated with the severity of airway obstruction and inflammation in asthma, and were found to be unaffected by GC in vitro. As IL-17 is overexpressed in neutrophilic asthma and contributes to steroid insensitivity in different cell types, we hypothesized that NETs formation in asthmatic airways would be resistant to GC through an IL-17 mediated pathway.

Methods

Six neutrophilic severe asthmatic horses and six healthy controls were studied while being treated with dexamethasone. Lung function, bronchoalveolar lavage fluid (BALF) cytology and NETs formation, as well as the expression of CD11b and CD13 by blood and airway neutrophils were evaluated. The expression of IL-17 and its role in NETs formation were also studied.

Results

Airway neutrophils from asthmatic horses, as opposed to blood neutrophils, enhanced NETs formation, which was then decreased by GC. GC also tended to decrease the expression of CD11b in blood neutrophils, but not in airway neutrophils. IL-17 mRNA was increased in BALF cells of asthmatic horses and was unaffected by GC. However, both GC and IL-17 inhibited NETs formation in vitro.

Conclusion

GC decreased NETs formation in vitro and also in vivo in the lungs of asthmatic horses. However, airway neutrophil activation during asthmatic inflammation was otherwise relatively insensitive to GC. The contribution of IL-17 to these responses requires further study.

     

EBI2 Expression and Function: Robust in Memory Lymphocytes and Increased by Natalizumab in Multiple Sclerosis

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Diversity and abundance of echinoderms from the reef lagoon at Cahuita National Park, Caribbean from Costa Rica

A total of 15 species of echinoderms (one asteroid, seven ophiuroids, five echinoids and two holothurians) were recorded at the Cahuita National Park reef lagoon, between September and October 2003, using a 1 m2 quadrant. The sites with coral substrate and algae were the most diverse, while those with seagrass and sand were the least. Ophiuroids were the most abundant group with 170 individuals, asteroids were the least abundant. Adding other studies and reports of echinoderms to this study, a total of 23 species have been found at Cahuita National Park, which is the most diverse area on the Caribbean of Costa Rica. We report nine new echinoderm records for Costa Rica's Caribbean.     

Serial cultivation of chicken keratinocytes, a composite cell type that accumulates lipids and synthesizes a novel beta-keratin

The epidermis of birds differs from that of mammals by the presence of intracellular lipid droplets and the absence of sebaceous glands. We describe here the cultivation of chicken epidermal keratinocytes; these cells cannot be grown in medium supplemented with the usual fetal bovine serum even in the presence of supporting 3T3 cells, but they can grow from single cells in the presence of supporting 3T3 cells and 10% chicken serum. As revealed by their cell structure, their protein composition, and their gene expression, chicken keratinocytes possess the general properties of mammalian keratinocytes. They ultimately undergo in culture a process of terminal differentiation in which their nucleus is destroyed and a cornified envelope is formed. Chicken keratinocytes also show important properties that mammalian keratinocytes do not possess: they accumulate neutral lipids, usually in the form of a single perinuclear droplet; they accumulate carotenoids; they synthesize beta-keratins; and their multiplication requires a non-lipid factor, present in chicken serum but not in fetal calf serum. The lipid-synthesizing function of sebocytes in mammals is carried out by the keratinocytes themselves in birds. The availability of cultured chicken keratinocytes should allow studies that were hitherto impossible such as the tracing of the keratinocyte lineage during development of the chicken embryo and the investigation of the complete life cycle of viruses that require specific chicken keratinocyte products (such as Marek's disease virus).     

Assignment of the CO-sensitive carboxyl group in mitochondrial forms of cytochrome c oxidase using yeast mutants

Point mutations of E243D and I67N were introduced into subunit I of a 6histidine-tagged (6H-WT) form of yeast Saccharomyces cerevisiae mitochondrial cytochrome c oxidase. The two mutants (6H-E243D(I) and 6H-I67N(I)) were purified and showed ≈50 and 10% of the 6H-WT turnover number. Light-induced CO photolysis FTIR difference spectra of the 6H-WT showed a peak/trough at 1749/1740cm(-1), as seen in bovine CcO, which downshifted by 7cm(-1) in D(2)O. The bands shifted to 1736/1762cm(-1) in 6H-E243D(I), establishing that the carboxyl group affected by CO binding in mitochondrial CcOs is E243. In 6H-I67N(I), the trough at 1740cm(-1) was shifted to 1743cm(-1) and its accompanying peak intensity was greatly reduced. This confirms that the I67N mutation interferes with conformational alterations around E243. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).     

New insight into the history of domesticated apple: secondary contribution of the European wild apple to the genome of cultivated varieties

The apple is the most common and culturally important fruit crop of temperate areas. The elucidation of its origin and domestication history is therefore of great interest. The wild Central Asian species Malus sieversii has previously been identified as the main contributor to the genome of the cultivated apple (Malus domestica), on the basis of morphological, molecular, and historical evidence. The possible contribution of other wild species present along the Silk Route running from Asia to Western Europe remains a matter of debate, particularly with respect to the contribution of the European wild apple. We used microsatellite markers and an unprecedented large sampling of five Malus species throughout Eurasia (839 accessions from China to Spain) to show that multiple species have contributed to the genetic makeup of domesticated apples. The wild European crabapple M. sylvestris, in particular, was a major secondary contributor. Bidirectional gene flow between the domesticated apple and the European crabapple resulted in the current M. domestica being genetically more closely related to this species than to its Central Asian progenitor, M. sieversii. We found no evidence of a domestication bottleneck or clonal population structure in apples, despite the use of vegetative propagation by grafting. We show that the evolution of domesticated apples occurred over a long time period and involved more than one wild species. Our results support the view that self-incompatibility, a long lifespan, and cultural practices such as selection from open-pollinated seeds have facilitated introgression from wild relatives and the maintenance of genetic variation during domestication. This combination of processes may account for the diversification of several long-lived perennial crops, yielding domestication patterns different from those observed for annual species.     

Tetrahydro iso-alpha acids from hops improve glucose homeostasis and reduce body weight gain and metabolic endotoxemia in high-fat diet-fed mice

Obesity and related metabolic disorders such as insulin resistance and type 2 diabetes are associated with a low-grade inflammatory state possibly through changes in gut microbiota composition and the development of higher plasma lipopolysaccharide (LPS) levels, i.e. metabolic endotoxemia. Various phytochemical compounds have been investigated as potential tools to regulate these metabolic features. Humulus lupulus L. (hops) contains several classes of compounds with anti-inflammatory potential. Recent evidence suggests that hops-derived compounds positively impact adipocyte metabolism and glucose tolerance in obese and diabetic rodents via undefined mechanisms. In this study, we found that administration of tetrahydro iso-alpha acids (termed META060) to high-fat diet (HFD)-fed obese and diabetic mice for 8 weeks reduced body weight gain, the development of fat mass, glucose intolerance, and fasted hyperinsulinemia, and normalized insulin sensitivity markers. This was associated with reduced portal plasma LPS levels, gut permeability, and higher intestinal tight junction proteins Zonula occludens-1 and occludin. Moreover, META060 treatment increased the plasma level of the anti-inflammatory cytokine interleukin-10 and decreased the plasma level of the pro-inflammatory cytokine granulocyte colony-stimulating factor. In conclusion, this research allows us to decipher a novel mechanism contributing to the positive effects of META060 treatment, and supports the need to investigate such compounds in obese and type 2 diabetic patients.     

Mu-opioid receptors and dietary protein stimulate a gut-brain neural circuitry limiting food intake

Intestinal gluconeogenesis is involved in the control of food intake. We show that mu-opioid receptors (MORs) present in nerves in the portal vein walls respond to peptides to regulate a gut-brain neural circuit that controls intestinal gluconeogenesis and satiety. In vitro, peptides and protein digests behave as MOR antagonists in competition experiments. In vivo, they stimulate MOR-dependent induction of intestinal gluconeogenesis via activation of brain areas receiving inputs from gastrointestinal ascending nerves. MOR-knockout mice do not carry out intestinal gluconeogenesis in response to peptides and are insensitive to the satiety effect induced by protein-enriched diets. Portal infusions of MOR modulators have no effect on food intake in mice deficient for intestinal gluconeogenesis. Thus, the regulation of portal MORs by peptides triggering signals to and from the brain to induce intestinal gluconeogenesis are links in the satiety phenomenon associated with alimentary protein assimilation.