Emerging evidence indicates that airway epithelial barrier function is compromised in asthma, a disease characterized by Th2-skewed immune response against inhaled allergens, but the mechanisms involved are not well understood. The purpose of this study was to investigate the effects of Th2-type cytokines on airway epithelial barrier function. 16HBE14o- human bronchial epithelial cells monolayers were grown on collagen coated Transwell inserts. The basolateral or apical surfaces of airway epithelia were exposed to human interleukin-4 (IL-4), IL-13, IL-25, IL-33, thymic stromal lymphopoietin (TSLP) alone or in combination at various concentrations and time points. We analyzed epithelial apical junctional complex (AJC) function by measuring transepithelial electrical resistance (TEER) and permeability to FITC-conjugated dextran over time. We analyzed AJC structure using immunofluorescence with antibodies directed against key junctional components including occludin, ZO-1, β-catenin and E-cadherin. Transepithelial resistance was significantly decreased after both basolateral and apical exposure to IL-4. Permeability to 3 kDa dextran was also increased in IL-4-exposed cells. Similar results were obtained with IL-13, but none of the innate type 2 cytokines examined (TSLP, IL-25 or IL-33) significantly affected barrier function. IL-4 and IL-13-induced barrier dysfunction was accompanied by reduced expression of membrane AJC components but not by induction of claudin- 2. Enhanced permeability caused by IL-4 was not affected by wortmannin, an inhibitor of PI3 kinase signaling, but was attenuated by a broad spectrum inhibitor of janus associated kinases. Our study indicates that IL-4 and IL-13 have disruptive effect on airway epithelial barrier function. Th2-cytokine induced epithelial barrier dysfunction may contribute to airway inflammation in allergic asthma.

The central nervous system maintains the potential for molecular and cellular plasticity throughout life. This flexibility underlies fundamental features of neural circuitry including the brain's ability to sense, store, and properly adapt to everchanging external stimuli on time scales from seconds to years. Evidence for most forms of plasticity are centered around changes in neuronal structure and synaptic strength, however recent data suggests that myelinating oligodendrocytes exhibit certain forms of plasticity in the adult. This plasticity ranges from the generation of entirely new myelinating cells to more subtle changes in myelin sheath length, thickness, and distribution along axons. The extent to which these changes dynamically modify axonal function and neural circuitry and whether they are directly related to mechanisms of learning and memory remains an open question. Here we describe different forms of myelin plasticity, highlight some recent evidence for changes in myelination throughout life, and discuss how defects in these forms of plasticity could be associated with cognitive decline in aging.

rotein isolation is one of the oldest 'biotechnologies' , but the demands from proteomics for the purification of potentially vast numbers of proteins is driving new developments in long-established techniques. "Researchers working in genomics are looking for the next step to fully understand the results of their sequence analysis-the proteins that the genome expresses-in the context of systems biology," says Anke Cassing, associate director for corporate strategy at Qiagen in Hilden, Germany. "The delicate interplay of proteins is, of course, also of extreme interest to pharmaceutical companies, which are always on the lookout for new drug targets." There is increasing demand from researchers producing biopharmaceuticals-antibodies and proteins used as drugs. "There's a driving force towards protein purification, separation and analysis," says Carsten Buhlmann, product manager at Agilent, based in Palo Alto, California. "Especially for the biopharmaceuticals, there's a high demand for purity of these proteins that are used for drugs and have to get through all the regulations." For virtually all applications, researchers need to maintain a protein's biological activity, which can rule out some purification processes. Proteins can be fragile and easily denatured, and many of the most important are insoluble in the most common media. "If you look at the average protein,it's quite complex,it's a buzzing,vibrating moleculeit's not a fixed structure," says Allan Simpson, vice-president for product development at the protein separations division of GE Healthcare Biosciences in Uppsala, Sweden. "They're very hard to handle, they're difficult to purify, they can aggregate easily-these are very hard things to manipulate." Proteomics workhorse With proteins taking centre stage in many laboratories, equipment developers are rolling out a new generation of automated systems to take the grind out of separating and purifying proteins of interest. Chromatographic separation is one of the basic proteinpurification techniques and one platform that is emerging as a workhorse of the large proteomics lab is ÄKTAxpress. Made by GE Healthcare, this is a dedicated high-throughput multistep chromatography system for purifying histidine (His)and glutathione-S-transferase (GST)-tagged recombinant proteins. GE began developing the platform in the late 1990s after realizing that there were not enough trained chromatographers to produce proteins in the quantities and varieties demanded by post-genomic researchers."We decided to see if we could automate a system that would be better than the current technologies at solving that problem," Simpson says."Instead of taking a robot and automating the current system, we set out to develop a protein purification technology feature Allan Simpson: membrane proteins will be "the pot of gold". GE HEALTHCARE Large-scale protein production needs equally high-throughput analysis.

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Synthetic biology has created oscillators, latches, logic gates, logarithmically linear circuits, and load drivers that have electronic analogs in living cells. The ubiquitous operational amplifier, which allows circuits to operate robustly and precisely has not been built with biomolecular parts. As in electronics, a biological operational-amplifier could greatly improve the predictability of circuits despite noise and variability, a problem that all cellular circuits face. Here, we show how to create a synthetic three-stage inducer-input operational amplifier with a fast CRISPR-based differential-input push-pull stage, a slow transcription-and-translation amplification stage, and a fast-enzymatic output stage. Our "Bio-OpAmp" uses only 5 proteins including dCas9. It expands the toolkit of fundamental analog circuits in synthetic biology and provides a simple circuit motif for robust and precise molecular homeostasis.