Biomarker discovery in asthma‐related inflammation and remodeling

Asthma is a complex inflammatory disease of airways. A network of reciprocal interactions between inflammatory cells, peptidic mediators, extracellular matrix components, and proteases is thought to be involved in the installation and maintenance of asthma‐related airway inflammation and remodeling. To date, new proteic mediators displaying significant activity in the pathophysiology of asthma are still to be unveiled. The main objective of this study was to uncover potential target proteins by using surface‐enhanced laser desorption/ionization‐time of flight‐mass spectrometry (SELDI‐TOF‐MS) on lung samples from mouse models of allergen‐induced airway inflammation and remodeling. In this model, we pointed out several protein or peptide peaks that were preferentially expressed in diseased mice as compared to controls. We report the identification of different five proteins: found inflammatory zone 1 or RELMα (FIZZ‐1), calcyclin (S100A6), clara cell secretory protein 10 (CC10), Ubiquitin, and Histone H4.     

miRNAS in normal and diseased skeletal muscle

The last 20 years have witnessed major advances in the understanding of muscle diseases and significant inroads are being made to treat muscular dystrophy. However, no curative therapy is currently available for any of the muscular dystrophies, despite the immense progress made using several approaches and only palliative and symptomatic treatment is available for patients. The discovery of miRNAs as new and important regulators of gene expression is expected to broaden our biological understanding of the regulatory mechanism in muscle by adding another dimension of regulation to the diversity and complexity of gene-regulatory networks. As important regulators of muscle development, unravelling the regulatory circuits involved may be challenging, given that a single miRNA can regulate the expression of many mRNA targets. Although the identification of the regulatory targets of miRNAs in muscle is a challenge, it will be critical for placing them in genetic pathways and biological contexts. Therefore, combining informatics, biochemical and genetic approaches will not only expected to reveal the elucidation of the miRNA regulatory network in skeletal muscle and to bring a better knowledge on muscle tissue regulation but will also raise new opportunities for therapeutic intervention in muscular dystrophies by identifying candidate miRNAs as potential targets for clinical application.     

Extracts from the bark of Fagara heitzii (Aubr. et Pel.) (Rutaceae) tree are toxic to two weevils and the American cockroach

The bark of the Fagara heitzii tree in the west‐central African Republic of Congo (Congo–Brazzaville) is known anecdotally to provide protection for human residents against fleas and to be of use as a narcotic in fishing (similar to rotenone). We found that powder and hexane extracts from the bark of the Fagara heitzii tree contain insecticidal compounds. Dried powder (14.5 mg) on the bottom of a Petri dish is the residue at 14.494 mg per dish (LD₅₀) for 20 adult maize weevils Sitophilus zeamays after four days. The LD₅₀ of the same material to 20 adult cowpea weevils Callosobruchus maculatus was slightly higher at 16.144 mg/dish (after 48 h). These weevils cause significant economic damage to cowpea and maize in Congo–Brazzaville. Hexane extracts of the bark of Fagara heitzii were also toxic to these weevils. Symptoms of toxicity suggested the extracts were slow‐acting nerve poisons or respiratory inhibitors or both. The time needed to develop full toxicity suggested a respiratory poison. The hexane extract was also toxic to the American cockroach Periplaneta americana. The symptoms in the cockroach were similar, but cockroaches also exhibited apparent escape attempts suggesting they could detect the compounds. Signs of apparent irritation or exaggerated locomotion in all three insects also suggested irritation or nerve effects.     

Genetic specificity and potential for local adaptation between dengue viruses and mosquito vectors

Background  

Several observations support the hypothesis that vector-driven selection plays an important role in shaping dengue virus (DENV) genetic diversity. Clustering of DENV genetic diversity at a particular location may reflect underlying genetic structure of vector populations, which combined with specific vector genotype × virus genotype (G × G) interactions may promote adaptation of viral lineages to local mosquito vector genotypes. Although spatial structure of vector polymorphism at neutral genetic loci is well-documented, existence of G × G interactions between mosquito and virus genotypes has not been formally demonstrated in natural populations. Here we measure G × G interactions in a system representative of a natural situation in Thailand by challenging three isofemale families from field-derived Aedes aegypti with three contemporaneous low-passage isolates of DENV-1.     

Distinct gene subsets in pterygia formation and recurrence: dissecting complex biological phenomenon using genome wide expression data

Background

Pterygium is a common ocular surface disease characterized by fibrovascular invasion of the cornea and is sight-threatening due to astigmatism, tear film disturbance, or occlusion of the visual axis. However, the mechanisms for formation and post-surgical recurrence of pterygium are not understood, and a valid animal model does not exist. Here, we investigated the possible mechanisms of pterygium pathogenesis and recurrence.

Methods

First we performed a genome wide expression analysis (human Affymetrix Genechip, >22000 genes) with principal component analysis and clustering techniques, and validated expression of key molecules with PCR. The controls for this study were the un-involved conjunctival tissue of the same eye obtained during the surgical resection of the lesions. Interesting molecules were further investigated with immunohistochemistry, Western blots, and comparison with tear proteins from pterygium patients.

Results

Principal component analysis in pterygium indicated a signature of matrix-related structural proteins, including fibronectin-1 (both splice-forms), collagen-1A2, keratin-12 and small proline rich protein-1. Immunofluorescence showed strong expression of keratin-6A in all layers, especially the superficial layers, of pterygium epithelium, but absent in the control, with up-regulation and nuclear accumulation of the cell adhesion molecule CD24 in the pterygium epithelium. Western blot shows increased protein expression of beta-microseminoprotein, a protein up-regulated in human cutaneous squamous cell carcinoma. Gene products of 22 up-regulated genes in pterygium have also been found by us in human tears using nano-electrospray-liquid chromatography/mass spectrometry after pterygium surgery. Recurrent disease was associated with up-regulation of sialophorin, a negative regulator of cell adhesion, and never in mitosis a-5, known to be involved in cell motility.

Conclusion

Aberrant wound healing is therefore a key process in this disease, and strategies in wound remodeling may be appropriate in halting pterygium or its recurrence. For patients demonstrating a profile of 'recurrence', it may be necessary to manage as a poorer prognostic case and perhaps, more adjunctive treatment after resection of the primary lesion.     

Detrimental Effects of Microgravity on Mouse Preimplantation Development In Vitro

Sustaining life beyond Earth either on space stations or on other planets will require a clear understanding of how the space environment affects key phases of mammalian reproduction. However, because of the difficulty of doing such experiments in mammals, most studies of reproduction in space have been carried out with other taxa, such as sea urchins, fish, amphibians or birds. Here, we studied the possibility of mammalian fertilization and preimplantation development under microgravity (µG) conditions using a three-dimensional (3D) clinostat, which faithfully simulates 10^–3 G using 3D rotation. Fertilization occurred normally in vitro under µG. However, although we obtained 75 healthy offspring from µG-fertilized and -cultured embryos after transfer to recipient females, the birth rate was lower than among the 1G controls. Immunostaining demonstrated that in vitro culture under µG caused slower development and fewer trophectoderm cells than in 1G controls but did not affect polarization of the blastocyst. These results suggest for the first time that fertilization can occur normally under µG environment in a mammal, but normal preimplantation embryo development might require 1G.     

Probiotics Prevent Intestinal Barrier Dysfunction in Acute Pancreatitis in Rats via Induction of Ileal Mucosal Glutathione Biosynthesis

Background

During acute pancreatitis (AP), oxidative stress contributes to intestinal barrier failure. We studied actions of multispecies probiotics on barrier dysfunction and oxidative stress in experimental AP.

Methodology/Principal Findings

Fifty-three male Spraque-Dawley rats were randomly allocated into five groups: 1) controls, non-operated, 2) sham-operated, 3) AP, 4) AP and probiotics and 5) AP and placebo. AP was induced by intraductal glycodeoxycholate infusion and intravenous cerulein (6 h). Daily probiotics or placebo were administered intragastrically, starting five days prior to AP. After cerulein infusion, ileal mucosa was collected for measurements of E. coli K12 and ⁵¹Cr-EDTA passage in Ussing chambers. Tight junction proteins were investigated by confocal immunofluorescence imaging. Ileal mucosal apoptosis, lipid peroxidation, and glutathione levels were determined and glutamate-cysteine-ligase activity and expression were quantified. AP-induced barrier dysfunction was characterized by epithelial cell apoptosis and alterations of tight junction proteins (i.e. disruption of occludin and claudin-1 and up-regulation of claudin-2) and correlated with lipid peroxidation (r>0.8). Probiotic pre-treatment diminished the AP-induced increase in E. coli passage (probiotics 57.4±33.5 vs. placebo 223.7±93.7 a.u.; P<0.001), ⁵¹Cr-EDTA flux (16.7±10.1 vs. 32.1±10.0 cm/s10⁻⁶; P<0.005), apoptosis, lipid peroxidation (0.42±0.13 vs. 1.62±0.53 pmol MDA/mg protein; P<0.001), and prevented tight junction protein disruption. AP-induced decline in glutathione was not only prevented (14.33±1.47 vs. 8.82±1.30 nmol/mg protein, P<0.001), but probiotics even increased mucosal glutathione compared with sham rats (14.33±1.47 vs. 10.70±1.74 nmol/mg protein, P<0.001). Glutamate-cysteine-ligase activity, which is rate-limiting in glutathione biosynthesis, was enhanced in probiotic pre-treated animals (probiotics 2.88±1.21 vs. placebo 1.94±0.55 nmol/min/mg protein; P<0.05) coinciding with an increase in mRNA expression of glutamate-cysteine-ligase catalytic (GCLc) and modifier (GCLm) subunits.

Conclusions

Probiotic pre-treatment diminished AP-induced intestinal barrier dysfunction and prevented oxidative stress via mechanisms mainly involving mucosal glutathione biosynthesis.