The phase behavior of lipid monolayers containing pulmonary surfactant protein C studied by fluorescence light microscopy

Three compounds of the pulmonary surfactant – dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG), and the surfactant associated protein C (SP-C) – were spread at the air-water interface of a Langmuir trough as a model system to mimic the properties of natural surfactant. Fluorescence microscopical images of the film formed at the interface were obtained during compression using a fluorescence dye bound covalently either to phosphatidylcholine or to SP-C. The images were quantified using statistical methods in respect to relative areas and relative fluorescence intensities of the domains found. In the early stage of compression, film pressure rose slightly and was accompanied by a phase separation which could be recognized in the images by the formation of bright and dark domains. On further compression, after a steep increase of film pressure, a plateau region of constant film pressure started abruptly. During compression in the plateau region, fluorescence intensity of the bright domain formed in the early stage of compression increased. The increasing fluorescence intensity, the non-Gaussian intensity distribution of the bright domain, and the small mean molecular area of the film in the plateau region gave rise to the assumption that multilayer structures were formed in the late stage of compression. The formation of the multilayer structures was fully reversible in repeated compression-expansion cycles including the plateau region of the phase diagram. The ability of lipid/SP-C mixtures to form reversible multilayer structures during compression may be relevant to stability in lungs during expiration and inhalation. Received: 13 February 1997 / Accepted: 22 May 1997     

Functional analysis of a complex oncogene arrangement in biotype III Agrobacterium tumefaciens strains

The ubiquitous grapevine-associated octopine/cucumopine Ti plasmids of biotype III Agrobacterium tumefaciens strains carry two T regions, TA and TB, with a complex oncogene arrangement. Within the octopine/cucumopine group, two main strain types were identified: large TA strains with a TA region resembling the TL region of the biotype I octopine strain Ach5 and small TA strains with a similar T region organization as the large TA strains but with a large internal TA deletion. Structural and functional studies of the representative large TA strain Tm4 revealed six oncogenes. Each oncogene was inserted in a disarmed vector and tested for biological activity using the corresponding oncogenes of Ach5 as standards. Five Tm4 oncogenes, TA-iaaM, T-ipt, T-6b, TB-iaaH and TB-iaaM, were shown to be active, the IS-interrupted TA-iaaH gene was inactive. To study the role of each gene in the pTiTm4 context, several single and multiple pTiTm4 mutations were constructed. It was shown that whereas TA-iaaM and TB-iaaH are essential for tumour formation on grapevine, T-ipt, T-6b and TB-iaaM are not. The avirulence of the TA-iaaM ^- mutant was shown to be due to an inhibitory effect of the T-ipt gene, since a TA-iaaM ^- /T-ipt ^- double mutant was fully virulent. We conclude that the TA-iaaM gene of large TA strains is specifically required to counteract the tumour growth inhibiting activity of the T-ipt gene. Both TA-iaaM and T-ipt are absent from the small TA strains. A model on the roles and interactions of the different oncogenes in large TA and small TA strains is presented.     

Molecular classification as prognostic factor and guide for treatment decision of pancreatic cancer

Clinico-pathological factors fail to consistently predict the outcome after pancreatic resection for pancreatic ductal adenocarcinoma (PDAC). PDACs show a high level of inter- and intra- tumor genetic heterogeneity. A molecular classification should help sort patients into less heterogeneous and more appropriate groups regarding the metastatic risk and the therapeutic response, with the consequences of better predicting evolution and better orienting the treatment. PDAC can be classified based on mutational subtypes and 18gene alterations. Whole-genome sequencing identified mutational signatures, mutational burden and hyper-mutated tumors with specific DNA repair defects. Their overlap/similarities allow the definition of molecular subtypes. DNA and RNA classifications can be used in prognosis assessment. They are useful in therapeutic choice for they allow the design of approaches that can predict the respective drug sensitivity of each molecular subtype. This review provides a comprehensive analysis of available molecular classifications in PDAC and how this can help guide clinical decisions.     

Therapeutic treatment with scFv–PLGA nanoparticles decreases pulmonary fungal load in a murine model of paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a systemic mycosis with lymphatic dissemination that is caused by Paracoccidioides species. Treatment of PCM consists of chemotherapeutics such as itraconazole, trimethoprim, sulfamethoxazole or amphotericin B. However, several studies are aiming to develop therapeutic alternatives for the treatment of fungal infection using new molecules as adjuvants. The single-chain variable fragments (scFv) from an antibody that mimics the main fungal component incorporated within poly(lactide-co-glycolic) acid (PLGA) nanoparticles helped treat the fungal disease. After expressing the scFv in Picchia pastoris (P. pastoris), the recombinant molecules were coupled with PLGA, and the BALB/c mice were immunized before or after infection with yeast Paracoccidioides brasiliensis (P. brasiliensis). Our results showed decreased disease progression and decreased fungal burden. Taken together, our results showed an increased of IFN-γ and IL-12 cytokine production and an increased number of macrophages and dendritic cells in the pulmonary tissue of BALB/c mice treated with a high concentration of our molecule. Our data further confirm that the scFv plays an important role in the treatment of experimental PCM.     

The Tol proteins of Escherichia coli and their involvement in the translocation of group A colicins

The Tol proteins are involved in outer membrane stability of Gram-negative bacteria. The TolQRA proteins form a complex in the inner membrane while TolB and Pal interact near the outer membrane. These two complexes are transiently connected by an energy-dependent interaction between Pal and TolA. The Tol proteins have been parasitized by group A colicins for their translocation through the cell envelope. Recent advances in the structure and energetics of the Tol system, as well as the interactions between the N-terminal translocation domain of colicins and the Tol proteins are presented.     

Inhibiting AKT Phosphorylation Employing Non-Cytotoxic Anthraquinones Ameliorates TH2 Mediated Allergic Airways Disease and Rhinovirus Exacerbation

Background

Severe asthma is associated with T helper (T_H) 2 and 17 cell activation, airway neutrophilia and phosphoinositide-3-kinase (PI3K) activation. Asthma exacerbations are commonly caused by rhinovirus (RV) and also associated with PI3K-driven inflammation. Anthraquinone derivatives have been shown to reduce PI3K-mediated AKT phosphorylation in-vitro.

Objective

To determine the anti-inflammatory potential of anthraquinones in-vivo.

Methods

BALB/c mice were sensitized and challenged with crude house dust mite extract to induce allergic airways disease and treated with mitoxantrone and a novel non-cytotoxic anthraquinone derivative. Allergic mice were also infected with RV1B to induce an exacerbation.

Results

Anthraquinone treatment reduced AKT phosphorylation, hypoxia-inducible factor-1α and vascular endothelial growth factor expression, and ameliorated allergen- and RV-induced airways hyprereactivity, neutrophilic and eosinophilic inflammation, cytokine/chemokine expression, mucus hypersecretion, and expression of T_H2 proteins in the airways. Anthraquinones also boosted type 1 interferon responses and limited RV replication in the lung.

Conclusion

Non-cytotoxic anthraquinone derivatives may be of therapeutic benefit for the treatment of severe and RV-induced asthma by blocking pro-inflammatory pathways regulated by PI3K/AKT.