Levels of plasma glycan-binding auto-IgG biomarkers improve the accuracy of prostate cancer diagnosis

Strategies to improve the early diagnosis of prostate cancer will provide opportunities for earlier intervention. The blood-based prostate-specific antigen (PSA) assay is widely used for prostate cancer diagnosis but specificity of the assay is not satisfactory. An algorithm based on serum levels of PSA combined with other serum biomarkers may significantly improve prostate cancer diagnosis. Plasma glycan-binding IgG/IgM studies suggested that glycan patterns differ between normal and tumor cells. We hypothesize that in prostate cancer glycoproteins or glycolipids are secreted from tumor tissues into the blood and induce auto-immunoglobulin (Ig) production. A 24-glycan microarray and a 5-glycan subarray were developed using plasma samples obtained from 35 prostate cancer patients and 54 healthy subjects to identify glycan-binding auto-IgGs. Neu5Acα2-8Neu5Acα2-8Neu5Acα (G81)-binding auto-IgG was higher in prostate cancer samples and, when levels of G81-binding auto-IgG and growth differentiation factor-15 (GDF-15 or NAG-1) were combined with levels of PSA, the prediction rate of prostate cancer increased from 78.2% to 86.2% than with PSA levels alone. The G81 glycan-binding auto-IgG fraction was isolated from plasma samples using G81 glycan-affinity chromatography and identified by N-terminal sequencing of the 50 kDa heavy chain variable region of the IgG. G81 glycan-binding 25 kDa fibroblast growth factor-1 (FGF1) fragment was also identified by N-terminal sequencing. Our results demonstrated that a multiplex diagnostic combining G81 glycan-binding auto-IgG, GDF-15/NAG-1 and PSA (≥?2.1 ng PSA/ml for cancer) increased the specificity of prostate cancer diagnosis by 8%. The multiplex assessment could improve the early diagnosis of prostate cancer thereby allowing the prompt delivery of prostate cancer treatment.

     

The microtubule lattice and plus-end association of Drosophila Mini spindles is spatially regulated to fine-tune microtubule dynamics

Individual microtubules (MTs) exhibit dynamic instability, a behavior in which they cycle between phases of growth and shrinkage while the total amount of MT polymer remains constant. Dynamic instability is promoted by the conserved XMAP215/Dis1 family of microtubule-associated proteins (MAPs). In this study, we conducted an in vivo structure-function analysis of the Drosophila homologue Mini spindles (Msps). Msps exhibits EB1-dependent and spatially regulated MT localization, targeting to microtubule plus ends in the cell interior and decorating the lattice of growing and shrinking microtubules in the cell periphery. RNA interference rescue experiments revealed that the NH(2)-terminal four TOG domains of Msps function as paired units and were sufficient to promote microtubule dynamics and EB1 comet formation. We also identified TOG5 and novel inter-TOG linker motifs that are required for targeting Msps to the microtubule lattice. These novel microtubule contact sites are necessary for the interplay between the conserved TOG domains and inter-TOG MT binding that underlies the ability of Msps to promote MT dynamic instability.     

Chronic intermittent hypoxia induces lung growth in adult mice

Obstructive sleep apnea (OSA) increases cardiovascular morbidity and mortality, which have been attributed to intermittent hypoxia (IH). The effects of IH on lung structure and function are unknown. We used a mouse model of chronic IH, which mimics the O(2) profile in patients with OSA. We exposed adult C57BL/6J mice to 3 mo of IH with a fraction of inspired oxygen (F(I)(O(2))) nadir of 5% 60 times/h during the 12-h light phase. Control mice were exposed to room air. Lung volumes were measured by quasistatic pressure-volume (PV) curves under anesthesia and by water displacement postmortem. Lungs were processed for morphometry, and the mean airspace chord length (Lm) and alveolar surface area were determined. Lung tissue was stained for markers of proliferation (proliferating cell nuclear antigen), apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling), and type II alveolar epithelial cells (surfactant protein C). Gene microarrays were performed, and results were validated by real-time PCR. IH increased lung volumes by both PV curves (air vs. IH, 1.16 vs. 1.44 ml, P < 0.0001) and water displacement (P < 0.01) without changes in Lm, suggesting that IH increased the alveolar surface area. IH induced a 60% increase in cellular proliferation, but the number of proliferating type II alveolocytes tripled. There was no increase in apoptosis. IH upregulated pathways of cellular movement and cellular growth and development, including key developmental genes vascular endothelial growth factor A and platelet-derived growth factor B. We conclude that IH increases alveolar surface area by stimulating lung growth in adult mice.     

Basolateral sorting signals regulating tissue-specific polarity of heteromeric monocarboxylate transporters in epithelia

Many solute transporters are heterodimers composed of non-glycosylated catalytic and glycosylated accessory subunits. These transporters are specifically polarized to the apical or basolateral membranes of epithelia, but this polarity may vary to fulfill tissue-specific functions. To date, the mechanisms regulating the tissue-specific polarity of heteromeric transporters remain largely unknown. Here, we investigated the sorting signals that determine the polarity of three members of the proton-coupled monocarboxylate transporter (MCT) family, MCT1, MCT3 and MCT4, and their accessory subunit CD147. We show that MCT3 and MCT4 harbor strong redundant basolateral sorting signals (BLSS) in their C-terminal cytoplasmic tails that can direct fusion proteins with the apical marker p75 to the basolateral membrane. In contrast, MCT1 lacks a BLSS and its polarity is dictated by CD147, which contains a weak BLSS that can direct Tac, but not p75 to the basolateral membrane. Knockdown experiments in MDCK cells indicated that basolateral sorting of MCTs was clathrin-dependent but clathrin adaptor AP1B-independent. Our results explain the consistently basolateral localization of MCT3 and MCT4 and the variable localization of MCT1 in different epithelia. They introduce a new paradigm for the sorting of heterodimeric transporters in which a hierarchy of apical and BLSS in the catalytic and/or accessory subunits regulates their tissue-specific polarity.     

Structural and functional development of the respiratory system in a newborn marsupial with cutaneous gas exchange

Marsupials are born with structurally immature lungs and rely, to varying degrees, on cutaneous gas exchange. With a gestation of 13 d and a birth weight of 13 mg, the fat-tailed dunnart (Sminthopsis crassicaudata) is one of the smallest and most immature marsupial newborns. We determined that the skin is almost solely responsible for gas exchange in the early neonatal period. Indeed, fewer than 35% of newborn dunnarts were observed to make any respiratory effort on the day of birth, with pulmonary ventilation alone not meeting the demand for oxygen until approximately 35 d postpartum. Despite the lack of pulmonary ventilation, the phrenic nerve had made contact with the diaphragm, and the respiratory epithelium was sufficiently developed to support gas exchange on the day of birth. Both type I and type II (surfactant-producing) alveolar epithelial cells were present, with fewer than 7% of the cells resembling undifferentiated alveolar epithelial precursor cells. The type I epithelial cells did, however, display thickened cytoplasmic extensions, leading to a high diffusion distance for oxygen. In addition, the architecture of the lung was immature, resembling the early canalicular stage, with alveolarization not commencing until 45 d postpartum. The pulmonary vasculature was also immature, with a centrally positioned single-capillary layer not evident until 100 d postbirth. These structural limitations may impede efficient pulmonary gas exchange, forcing the neonatal fat-tailed dunnart to rely predominately on its skin, a phenomenon supported by a low metabolic rate and small size.     

Generation and characterization of iUBC-KikGR photoconvertible transgenic mice for live time-lapse imaging during development

A transgenic mouse line named iUBC-KikGR was generated, which expresses the photoconvertible fluorescent protein Kikume Green-Red (KikGR) under the control of the human Ubiquitin C promoter. KikGR is natively a green fluorophore, which can be converted into a red fluorophore upon exposure to UV light. KikGR is expressed broadly throughout transgenic embryos from the two-cell stage onward and in the adult. Specificity of photoconversion can range from the entire embryo to a region of an organ, to a few individual cells, depending on the needs of the experimenter. Cell movements, tissue reorganization, and migration can then be observed in real time by culturing the tissue of interest as an explant on the microscope stage. The iUBC-KikGR transgenic line represents a singular genetic reagent, which can be used for fate mapping, lineage tracing, and live visualization of cell behaviors and tissue movements in multiple organs at multiple time points.     

The Protein Information and Property Explorer 2: gaggle-like exploration of biological proteomic data within one webpage

The Protein Information and Property Explorer 2 (PIPE2) is an enhanced software program and updated web application that aims at providing the proteomic researcher a simple, intuitive user interface through which to begin inquiry into the biological significance of a list of proteins typically produced by MS/MS proteomic processing software. PIPE2 includes an improved interface, new data visualization options, and new data analysis methods for combining disparate, but related, data sets. In particular, PIPE2 has been enhanced to handle multi-dimensional data such as protein abundance, gene expression, and/or interaction data. The current architecture of PIPE2, modeled after that of Gaggle (a programming infrastructure for interoperability between separately developed software tools), contains independent functional units that can be instantiated and pieced together at the user's discretion to form a pipelined analysis workflow. Among these functional units is the Network Viewer component, which adds rich network analysis capabilities to the suite of existing proteomic web resources. Additionally, PIPE2 implements a framework within which new analysis procedures can be easily deployed and distributed over the World Wide Web. PIPE2 is available as a web service at http://pipe2.systemsbiology.net/.     

Antimicrobial strength increases with group size: implications for social evolution

We hypothesize that aggregations of animals are likely to attract pathogenic micro-organisms and that this is especially the case for semisocial and eusocial insects where selection ultimately led to group sizes in the thousands or even millions, attracting the epithet 'superorganism'. Here, we analyse antimicrobial strength, per individual, in eight thrips species (Insecta: Thysanoptera) that present increasing innate group sizes and show that species with the largest group size (100-700) had the strongest antimicrobials, those with smaller groups (10-80) had lower antimicrobial activity, while solitary species showed none. Species with large innate group sizes showed strong antimicrobial activity while the semisocial species showed no activity until group size increased sufficiently to make activity detectable. The eusocial species behaved in a similar way, with detectable activity appearing once group size exceeded 120. These analyses show that antimicrobial strength is determined by innate group size. This suggests that the evolution of sociality that, by definition, increases group size, may have had particular requirements for defences against microbial pathogens. Thus, increase in group size, accompanied by increased antibiotic strength, may have been a critical factor determining the 'point of no return', early in the evolution of social insects, beyond which the evolution of social anatomical and morphological traits was irreversible. Our data suggest that traits that increase group size in general are accompanied by increased antimicrobial strength and that this was critical for transitions from solitary to social and eusocial organization.