Interleukin-10 protects cultured fetal rat type II epithelial cells from injury induced by mechanical stretch

Mechanical ventilation plays a central role in the pathogenesis of bronchopulmonary dysplasia. However, the mechanisms by which excessive stretch of fetal or neonatal type II epithelial cells contributes to lung injury are not well defined. In these investigations, isolated embryonic day 19 fetal rat type II epithelial cells were cultured on substrates coated with fibronectin and exposed to 5% or 20% cyclic stretch to simulate mechanical forces during lung development or lung injury, respectively. Twenty percent stretch of fetal type II epithelial cells increased necrosis, apoptosis, and proliferation compared with control, unstretched samples. By ELISA and real-time PCR (qRT-PCR), 20% stretch increased secretion of IL-8 into the media and IL-8 gene expression and inhibited IL-10 release. Interestingly, administration of recombinant IL-10 before 20% stretch did not affect cell lysis but significantly reduced apoptosis and IL-8 release compared with stretched samples without IL-10. Collectively, our studies suggest that IL-10 may play an important role in protection of fetal type II epithelial cells from injury secondary to stretch.     

Diet-induced obesity is linked to marked but reversible alterations in the mouse distal gut microbiome

We have investigated the interrelationship between diet, gut microbial ecology, and energy balance using a mouse model of obesity produced by consumption of a prototypic Western diet. Diet-induced obesity (DIO) produced a bloom in a single uncultured clade within the Mollicutes class of the Firmicutes, which was diminished by subsequent dietary manipulations that limit weight gain. Microbiota transplantation from mice with DIO to lean germ-free recipients promoted greater fat deposition than transplants from lean donors. Metagenomic and biochemical analysis of the gut microbiome together with sequencing and metabolic reconstructions of a related human gut-associated Mollicute (Eubacterium dolichum) revealed features that may provide a competitive advantage to members of the bloom in the Western diet nutrient milieu, including import and processing of simple sugars. Our study illustrates how combining comparative metagenomics with gnotobiotic mouse models and specific dietary manipulations can disclose the niches of previously uncharacterized members of the gut microbiota.     

Activin signals via SMAD2/3 between germ and somatic cells in the human fetal ovary and regulates kit ligand expression

Ovarian germ cell survival is dependent upon the formation of primordial follicles, which occurs during fetal life in the human. Activin contributes to germ cell proliferation and survival at this time. SMADs2 and 3 are central elements in the activin signalling pathway and thus indicate sites of activin action. We have investigated the expression and localisation of SMADs2 and 3 in the fetal ovary between 14 and 20 weeks gestation, i.e. preceding and during primordial follicle formation. SMAD3 mRNA expression increased 1.9 fold (P = 0.02). SMAD2 and 3 proteins were localised by immunofluorescence to the nuclei of three distinct populations of somatic cells: (a) stromal cells between clusters of germ cells; (b) some somatic cells intermingled with activin βA-expressing germ cells; (c) pre-granulosa cells surrounding primordial follicles. Germ cells did not express SMAD2 or 3. Activin A increased and follistatin decreased phosphorylation of SMAD2/3 in vitro, and activin increased SMAD2 and decreased KITLG mRNA expression. It therefore appears that somatic cells are the targets for activin signalling in the developing ovary. The effects of activin on germ cells are indirect and include mediation by the kit ligand/c-Kit pathway, rather than being an autocrine germ cell effect.     

Localization of endothelial nitric-oxide synthase phosphorylated on serine 1179 and nitric oxide in Golgi and plasma membrane defines the existence of two pools of active enzyme.

The subcellular localization of endothelial nitric-oxide synthase (eNOS) is critical for optimal coupling of extracellular stimulation to nitric oxide production. Because eNOS is activated by Akt-dependent phosphorylation to produce nitric oxide (NO), we determined the subcellular distribution of eNOS phosphorylated on serine 1179 using a variety of methodologies. Based on sucrose gradient fractionation, phosphorylated-eNOS (P-eNOS) was found in both caveolin-1-enriched membranes and intracellular domains. Co-transfection of eNOS with Akt and stimulation of endothelial cells with vascular endothelial growth factor (VEGF) increased the ratio of P-eNOS to total eNOS but did not change the relative intracellular distribution between these domains. The proper localization of eNOS to intracellular membranes was required for agonist-dependent phosphorylation on serine 1179, since VEGF did not increase eNOS phosphorylation in cells transfected with a non-acylated, mistargeted form of eNOS. Confocal imaging of P-eNOS and total eNOS pools demonstrated co-localization in the Golgi region and plasmalemma of transfected cells and native endothelial cells. Finally, VEGF stimulated a large increase in NO localized in both the perinuclear region and the plasma membrane of endothelial cells. Thus, activated, phosphorylated eNOS resides in two cellular compartments and both pools are VEGF-regulated to produce NO.     

Vomiting as a diagnostic aid in acute ischaemic cardiac pain.

The incidence of vomiting before the administration of analgesics was studied in 109 patients admitted to hospital as emergencies with prolonged ischaemic cardiac pain. In transmural myocardial infarction (58 patients) the incidence was 43% (anterior infarction 58%, inferior infarction 41%). Of the 23 patients with myocardial necrosis but without transmural infarction (that is, those with diffuse or subendocardial necrosis) and the 28 with coronary insufficiency but no necrosis, only one patient in each group experienced vomiting. When vomiting occurs early in association with cardiac pain transmural infarction may be expected in 90% of patients.