Characterization of the complex formed between a potent neutralizing ovine-derived polyclonal anti-TNFα Fab fragment and human TNFα

TNFα (tumour necrosis factor α) is an early mediator in the systemic inflammatory response to infection and is therefore a therapeutic target in sepsis. AZD9773 is an ovine-derived, polyclonal anti-TNFα Fab fragment derived from a pool of serum and currently being developed as a treatment for severe sepsis and septic shock. In the present study, we show that although AZD9773 has a modest affinity for TNFα in a binding assay, the K_i in a cell-based assay is approximately four orders of magnitude lower. We show using SEC (size exclusion chromatography) that the maximum size of the complex between AZD9773 and TNFα is consistent with approximately 12 Fabs binding to one TNFα trimer. A number of approaches were taken to map the epitopes recognized by AZD9773. These revealed that a number of different regions on TNFα are involved in binding to the polyclonal Fab. The data suggest that there are probably three epitopes per monomer that are responsible for most of the inhibition by AZD9773 and that all three can be occupied at the same time in the complex. We conclude that AZD9773 is clearly demonstrated to bind to multiple epitopes on TNFα and suggest that the polyclonal nature may account, at least in part, for the very high potency observed in cell-based assays.     

Bacterial Populations (First Record) at Two Shallow Hydrothermal Vents of the Mexican Pacific West Coast

Thermophilic and metal-oxidizing bacteria were identified in shallow hydrothermal vents on the western Mexican coast. The role of these bacteria in biomineralization processes observed in the vents is explained, and the effect of the vents on biodiversity of prokaryotes is discussed. Research was done at two shallow hydrothermal vent sites: Bahía Concepción (BC) in the Baja California Peninsula and Punta Mita (PM), on the central Pacific coast. Temperature at the sediments proximal to the vents was similar, but the redox potentials (0.5 V in BC and ?0.3 V in PM) and pH (6.2 in BC and as low as 4.5 in PM) differed. The composition of the discharged water ranged from nearly seawater to lower-salinity fluids, and the gas phase was mainly CO₂ at BC and N₂ and CH₄ at PM. The study focuses on the biogeochemical processes related to the different species of bacteria present in the studied sites, which are involved in the anaerobic oxidation of methane (AOM), seawater sulfate reduction, and metal oxidation. The detected bacterial lineages represented typical deep vent species, which disproves a previous hypothesis that proposed that different consortia were populating deep and shallow hydrothermal vents. The results obtained here show that the main parameter affecting the bacterial groups present in shallow vents was the redox potential: gamma-, delta-, and epsilon proteobacteria as well as Bacteriodetes are present under the oxidizing conditions of BC, and Thermotogae, Aquificae, and Planctomycetes are present in PM. Sunlight abundance favored the prevalence of halophilic and Chlorofleaxae bacteria in both areas.     

Human monocyte‐derived macrophages spontaneously differentiated in vitro show distinct phenotypes

Tissue macrophages are resident phagocytes that acquire specific phenotypes according to the microenvironment. Morphological and functional heterogeneity has been evidenced in different homeostatic and pathological conditions. Indeed, the nature of macrophage subsets may have either harmful or beneficial functions in disease progression/resolution. Therefore the possibility to pharmacologically manipulate heterogeneity represents a relevant challenge. Since human tissue macrophages are not easily obtained, various in vitro models are currently used that do not adequately reflect the heterogeneity and plasticity of tissue macrophages. We had previously reported that two dominant and distinct macrophage morphotypes co‐exist in the same culture of human monocytes spontaneously differentiated for 7 days in autologous serum. The present study was aimed to the phenotypic characterization of these morphotypes, that is, round‐ and spindle‐shaped. We observed that, besides substantial differences in cytoskeleton architecture, round monocyte‐derived macrophages (MDMs) showed higher lipid content, increased macropinocytosis/efferocytosis capacity, and overexpression of CD163, interleukin (IL)‐10, and transforming growth factor (TGF) β2. Conversely, spindle MDMs exhibited enhanced respiratory burst and higher expression of the chemokine (C‐C motif) ligands 18 and 24 (CCL18 and CCL24). Overall, round MDMs show functional traits reminiscent of the non‐inflammatory and reparative M2 phenotype, whereas spindle MDMs exhibit a pro‐inflammatory profile and express genes driving lymphocyte activation and eosinophil recruitment. MDMs obtained in the culture condition herein described represent a valuable model to disentangle and manipulate the functional heterogeneity of tissue macrophages that has been disclosed in scenarios spanning from inflammatory and wounding responses to atherosclerotic lesions. J. Cell. Physiol. 228: 1464–1472, 2013. © 2012 Wiley Periodicals, Inc.     

EGFR through STAT3 modulates ΔN63α expression to sustain tumor‐initiating cell proliferation in squamous cell carcinomas

Many squamous cell carcinomas (SCCs) are characterized by high levels of EGFR and by overexpression of the ΔNp63α isoform. Here, we investigated the regulation of ΔNp63α expression upon EGFR activation and the role of the EGFR–ΔNp63α axis in proliferation of SCC tumor‐initiating cells (TICs). SCC cell lines A‐431, Cal‐27, and SCC‐25 treated with EGF showed a time‐dependent increase in ΔNp63α expression at the protein and mRNA levels, which was blocked by the tyrosine kinase inhibitor (TKI) Lapatinib. RNA interference experiments suggested the role of STAT3 in regulating ΔNp63α expression downstream of EGFR. Inactivation of EGFR by the monoclonal antibody Cetuximab and RNA interference against STAT3 or ΔNp63α impaired the TICs ability to grow under non‐differentiating conditions. Radiation treatment, which triggers EGFR activation, induced ΔNp63α accumulation without affecting TICs proliferation, whereas the combination Cetuximab plus radiation significantly reduced TICs growth under non‐differentiating conditions. Together, our findings provide evidence that ΔNp63α expression is regulated by EGFR activation through STAT3 and that the EGFR–ΔNp63α axis is crucial for proliferation of TICs present in SCCs. J. Cell. Physiol. 228: 871–878, 2013. © 2012 Wiley Periodicals, Inc.     

Aphid (Hemiptera: Aphidoidea) diversity in Tunisia in relation to seed potato production

Winged morphs of aphids were investigated from 2002 to 2004 in 4 Tunisian regions of potato seeds production in order to know the aphid diversity and the potential vectors of Potato Virus Y. This is a very important contribution to the knowledge of aphid fauna in Maghreb. A total of 50,030 aphids were caught using yellow water traps and one suction trap. 130 taxa were identified including 103 species. Ten species are well represented in all regions prospected and typical species were also observed in every region. Some differences in species diversity appeared between regions which are discussed considering weather condition and vegetation.     

Specificity of the rapid rK39 antigen-based immunochromatographic test Kalazar Detect(r) in patients with cutaneous leishmaniasis in Brazil

The aim of this study was to evaluate the specificity of a rapid immunochromatographic test that was developed to detect antibodies against the rK39 antigen for the diagnosis of visceral leishmaniasis (VL). This evaluation was performed using sera from patients with a confirmed diagnosis of active cutaneous leishmaniasis. The sera from 272 patients with a confirmed diagnosis of localised cutaneous leishmaniasis (CL) who resided in an area endemic for Leishmania braziliensis in Brazil were obtained before the initiation of antileishmanial treatment. Kalazar Detect^(r)(InBios, Seattle, WA) recombinant K39 antigen-based immunochromatographic strips were used according to the manufacturer''s instructions. The test results were evaluated independently by two examiners in sequential order. The positive controls for the test included five serum samples from five patients with parasitologically confirmed diagnosis of VL caused by Leishmania infantum in Brazil. Overall, 100% of the samples obtained from patients with CL were negative, confirming the absence of a serological cross-reaction for individuals with cutaneous disease when these patients were evaluated using the rapid test. The lack of a cross-reaction in patients who were infected by parasites of the same genus highlights the specificity of the rK39 antigen for the diagnosis of VL in areas with the sympatric circulation of L. braziliensis and L. infantum.     

Males with a Faster Courtship Display have More White Spots and Higher Pairing Success in the Diamond Firetail,Stagonopleura guttata

There is growing evidence that female mate choice could be based on a combination of multiple signals that often involve both ornamental colourful traits and behavioural displays. The Diamond Firetail is an Australian finch with a variable number of white spots on their black flank feathers. The number of white spots is a dimorphic characteristic: females have more spots than males, and males prefer females with many spots. Previously, we found assortative pairing for spot number despite the absence of experimental evidence for female preference for male spot number. Here, we test whether the male behavioural courtship display (bobbing while waving a grass stem) correlates with male spot number and pairing success. We also test whether male spot number predicts the outcome (winner or loser) of intrasexual competition over courtship materials (grass stem, perch, nest site). Males with many spots had higher pairing success, and male spot number correlated with the intensity of courtship display. In a multivariate statistical analysis, male courtship display was the stronger predictor of male pairing success. Finally, male spot number predicted the outcome of intrasexual interactions: males with many spots consistently won contests over grass stems, perches and nest sites. We suggest that intrasexual selection could favour male spot number, whereas courtship intensity appears to be under stronger intersexual selection.     

A Computational Model of Reactive Oxygen Species and Redox Balance in Cardiac Mitochondria

Elevated levels of reactive oxygen species (ROS) play a critical role in cardiac myocyte signaling in both healthy and diseased cells. Mitochondria represent the predominant cellular source of ROS, specifically the activity of complexes I and III. The model presented here explores the modulation of electron transport chain ROS production for state 3 and state 4 respiration and the role of substrates and respiratory inhibitors. Model simulations show that ROS production from complex III increases exponentially with membrane potential (ΔΨ_m) when in state 4. Complex I ROS release in the model can occur in the presence of NADH and succinate (reverse electron flow), leading to a highly reduced ubiquinone pool, displaying the highest ROS production flux in state 4. In the presence of ample ROS scavenging, total ROS production is moderate in state 3 and increases substantially under state 4 conditions. The ROS production model was extended by combining it with a minimal model of ROS scavenging. When the mitochondrial redox status was oxidized by increasing the proton permeability of the inner mitochondrial membrane, simulations with the combined model show that ROS levels initially decline as production drops off with decreasing ΔΨ_m and then increase as scavenging capacity is exhausted. Hence, this mechanistic model of ROS production demonstrates how ROS levels are controlled by mitochondrial redox balance.     

FAM111A Mutations Result in Hypoparathyroidism and Impaired Skeletal Development

Kenny-Caffey syndrome (KCS) and the similar but more severe osteocraniostenosis (OCS) are genetic conditions characterized by impaired skeletal development with small and dense bones, short stature, and primary hypoparathyroidism with hypocalcemia. We studied five individuals with KCS and five with OCS and found that all of them had heterozygous mutations in FAM111A. One mutation was identified in four unrelated individuals with KCS, and another one was identified in two unrelated individuals with OCS; all occurred de novo. Thus, OCS and KCS are allelic disorders of different severity. FAM111A codes for a 611 amino acid protein with homology to trypsin-like peptidases. Although FAM111A has been found to bind to the large T-antigen of SV40 and restrict viral replication, its native function is unknown. Molecular modeling of FAM111A shows that residues affected by KCS and OCS mutations do not map close to the active site but are clustered on a segment of the protein and are at, or close to, its outer surface, suggesting that the pathogenesis involves the interaction with as yet unidentified partner proteins rather than impaired catalysis. FAM111A appears to be crucial to a pathway that governs parathyroid hormone production, calcium homeostasis, and skeletal development and growth.