Cell surface profiling of cultured cells by direct hydrazide capture of oxidized glycoproteins

Glycoproteins are a particularly interesting subset of the cellular proteome as a high proportion of proteins present on the extracellular cell surface are glycosylated. These cell surface proteins are ideal targets for biologic drug therapies or for diagnostics tests. Here, we describe a modification of the well-described Cell Surface Capture (CSC) method for the selective isolation and identification of cell surface glycoproteins that contain N-linked carbohydrates. This modification, which we refer to as Direct Cell Surface Capture (D-CSC), is based on oxidation of cell surface glycans on intact cells, followed by direct conjugation of the oxidized oligosaccharides to a solid support using hydrazide chemistry, with no biotinylation step. As a proof-of-principle, we applied D-CSC to the analysis of cell surface membrane proteins of three adherent cancer cell lines (A549, OVCAR3, and U87MG) and compared our results to those published using the well-established Cell Surface Capture (CSC) method, demonstrating comparable selectivity for cell surface proteins. •A method enabling the identification of cell surface proteins from cells in culture is described.•Application of this method to profile the cell surface on three different cancer cell lines is included.

A multilevel conceptual framework on green practices: Transforming policies into actionable leadership and employee behavior

As organizations have recognized their cause/solution relationship with the environment, increasing attention is being given to the role of employees make in achieving green organizational objectives. Even though, business sustainability initiatives are often led by leaders; employee green behavior (EGB) plays a vital role in success of such initiatives. The current paper focuses on relatively less researched topic of EGB. It uses a narrative review approach to develop a multi-level conceptual framework that draws upon the connectivity of leadership influence at firm and team levels, and how this influences individual level EGB. The paper offers a holistic approach to influencing effective green strategies in organizational contexts. By doing so, it contributes to the larger debate on different dimensions, mechanisms, and levels of environmentally responsible behavior in organizational settings and opens up new avenues for multi-level and cross-layer empirical research.

Coral composition and bottom-wave metrics improve understanding of the patchiness of cyclone damage on reefs

Coral reefs are likely to be exposed to more intense cyclones under climate change. Cyclone impacts are spatially highly variable given complex hydrodynamics, and coral-specific sensitivity to wave impacts. Predicting reef vulnerability to cyclones is critical to management but requires high resolution environmental data that are difficult to obtain over broad spatial scales. Using 30m-resolution wave modelling, we tested cyclonic and non-cyclonic wave metrics as predictors of coral damage on 22 reefs after severe cyclone Ita impacted the northern Great Barrier Reef, Australia in 2014. Analyses of coral cover change accounting for the type of coral along a gradient of vulnerability to wave damage (e.g., massive, branching, Acroporids) excluded cyclone-generated surface wave metrics (derived from wave height) as important predictors. Increased bottom stress wave environment (near-bed wave orbital velocity) due to Ita (Ita-U_b) explained spatial patterns of 17% to 46% total coral cover loss only when the initial abundance of Acroporids was accounted for, and only when exceeding 35% cover. Greater coral losses occurred closer to the cyclone path irrespective of coral type. Massive and encrusting corals, however, had losses exacerbated in higher non-cyclonic bottom-wave energy environments (nc-U_b). The effect of community composition on structural vulnerability to wave damage was more important predicting damage that the magnitude of the cyclone-generated waves, especially when reefs are surveyed well beyond where damaging waves are expected to occur. Exposure to Ita-U_b was greater in typically high nc-U_b environments with relatively low cover of the most fragile morphologies explaining why these were the least affected overall. We reveal that the common surface-wave metrics of cyclone intensity may not always be able to predict spatial impacts and conclude that reef vulnerability assessments need to account for chronic wave patterns and differences in community composition in order to provide predictive tools for future conservation and restoration.

Immunoassay for Quantitative Detection of Antibody Transcytosis Across the Blood-Brain Barrier In Vitro

Automated high-throughput immunoassays are emerging as reliable analytic techniques for the quantitative detection of proteins from a variety of sample types. Herein, we describe a method using the Protein Simple Wes capillary-based automated immunoassays platform for the quantification of His- and HA-tagged antibody transcytosis across an in vitro transwell blood-brain barrier (BBB) model. Compared to conventional ELISA, fluorescence, and Mass Spec-based detection approaches, Wes provides comparable datasets with additional information regarding size, aggregation, and potential degradation of samples before and after BBB transcytosis. In this chapter, we have benchmarked our Wes technique against ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), using known BBB crossing (FC5) and non-crossing (A20.1) single domain antibodies.

Modulating antibody-dependent cellular cytotoxicity of epidermal growth factor receptor-specific heavy-chain antibodies through hinge engineering

Human IgG1 and IgG3 antibodies (Abs) can mediate Ab-dependent cellular cytotoxicity (ADCC), and engineering of the Ab Fc (point mutation; defucosylation) has been shown to affect ADCC by modulating affinity for FcRγIIIa. In the absence of a C_H 1 domain, many camelid heavy-chain Abs (HCAbs) naturally bear very long and flexible hinge regions connecting their V_H H and C_H 2 domains. To better understand the influence of hinge length and structure on HCAb ADCC, we produced a series of hinge-engineered epidermal growth factor receptor (EGFR)-specific chimeric camelid V_H H-human Fc Abs and characterized their affinities for recombinant EGFR and FcRγIIIa, their binding to EGFR-positive tumor cells, and their ability to elicit ADCC. In the case of one chimeric HCAb (EG2-hFc), we found that variants bearing longer hinges (IgG3 or camelid hinge regions) showed dramatically improved ADCC in comparison with a variant bearing the human IgG1 hinge, in similar fashion to a variant with reduced C_H 2 fucosylation. Conversely, an EG2-hFc variant bearing a truncated human IgG1 upper hinge region failed to elicit ADCC. However, there was no consistent association between hinge length and ADCC for four similarly engineered chimeric HCAbs directed against distinct EGFR epitopes. These findings demonstrate that the ADCC of some HCAbs can be modulated simply by varying the length of the Ab hinge. Although this effect appears to be heavily epitope-dependent, this strategy may be useful to consider during the design of V_H H-based therapeutic Abs for cancer.

Enhanced Delivery of Galanin Conjugates to the Brain through Bioengineering of the Anti-Transferrin Receptor Antibody OX26

The blood-brain barrier (BBB) is a formidable obstacle for brain delivery of therapeutic antibodies. However, antibodies against the transferrin receptor (TfR), enriched in brain endothelial cells, have been developed as delivery carriers of therapeutic cargoes into the brain via a receptor-mediated transcytosis pathway. In vitro and in vivo studies demonstrated that either a low-affinity or monovalent binding of these antibodies to the TfR improves their release on the abluminal side of the BBB and target engagement in brain parenchyma. However, these studies have been performed with mouse-selective TfR antibodies that recognize different TfR epitopes and have varied binding characteristics. In this study, we evaluated serum pharmacokinetics and brain and CSF exposure of the rat TfR-binding antibody OX26 affinity variants, having K_Ds of 5 nM, 76 nM, 108 nM, and 174 nM, all binding the same epitope in bivalent format. Pharmacodynamic responses were tested in the Hargreaves chronic pain model after conjugation of OX26 affinity variants with the analgesic and antiepileptic peptide, galanin. OX26 variants with affinities of 76 nM and 108 nM showed enhanced brain and cerebrospinal fluid (CSF) exposure and higher potency in the Hargreaves model, compared to a 5 nM affinity variant; lowering affinity to 174 nM resulted in prolonged serum pharmacokinetics, but reduced brain and CSF exposure. The study demonstrates that binding affinity optimization of TfR-binding antibodies could improve their brain and CSF exposure even in the absence of monovalent TfR engagement.

The role of bitewing radiographs--a review of current guidelines

This article sets out guidelines on the use of bitewing radiographs for the detection of dental caries, with suggested risk factors and recall intervals. It describes a case in which extensive carious lesions were not detected clinically, but were revealed when radiographs were taken during an orthodontic assessment.

Storage of blood for in vitro generation of dendritic cells

BACKGROUND

Since the development of techniques to cultivate DC from peripheral blood, there has been a great deal of interest in the use of these cells in immunotherapeutic strategies. In a clinical setting, delays often occur between when blood is drawn and when it is processed. We therefore investigated the effect of overnight storage on the yield, morphology and phenotype of DC cultured from the peripheral blood of healthy volunteers.

METHOD

Blood was processed either immediately, or after storage for 24 h in the fridge (4 degrees C) or at room temperature (RT, 20 degrees C). Samples were compared for starting cell number, DC yield and characteristics (morphology and phenotype).

RESULTS

The number of PBMC that could be obtained was significantly lower from the refrigerated samples compared with both the freshly processed sample and that stored at RT. Samples processed after overnight storage at RT yielded cells morphologically identical to DC cultured from freshly processed samples. Only when samples were both stored and processed cold did the cultured cells not have typical DC morphology. DC cultured from the refrigerated samples showed a significant reduction in MHC II expression compared with samples processed fresh or stored at RT. This expression increased slightly when the sample was first warmed. Total DC yield and the percentage yield of cultured DC was not significantly different for any of the groups.

DISCUSSION

We conclude that, if immediate processing of blood for in vitro generation of DC is not possible, samples should be stored at room temperature (approximately 20 degrees C).

The transcription factor E2F1 modulates apoptosis of neurons

The transcription factor E2F1 is known to mediate apoptosis in isolated quiescent and postmitotic cardiac myocytes, and its absence decreases the size of brain infarction following cerebral ischemia. To demonstrate directly that E2F1 modulates neuronal apoptosis, we used cultured cortical neurons to show a temporal association of the transcription and expression of E2F1 in neurons with increased neuronal apoptosis. Cortical neurons lacking E2F1 expression (derived from E2F1 -/- mice) were resistant to staurosporine-induced apoptosis as evidenced by the significantly lower caspase 3-like activity and a lesser number of cells with apoptotic morphology in comparison with cortical cultures derived from wild-type mice. Furthermore, overexpressing E2F1 alone using replication-deficient recombinant adenovirus was sufficient to cause neuronal cell death by apoptosis, as evidenced by the appearance of hallmarks of apoptosis, such as the threefold increase in caspase 3-like activity and increased laddered DNA fragmentation, in situ endlabeled DNA fragmentation, and numbers of neuronal cells with punctate nuclei. Taken together, we conclude that E2F1 plays a key role in modulating neuronal apoptosis.

Living with diabetes: issues for nursing practice

Discussion in this paper is based on findings drawn from research undertaken within a qualitative framework of analysis, and with the purpose of exploring people's perceptions of living with diabetes, including the nursing care they receive. A major theoretical concern is to demonstrate the importance of placing patients' and clients' experiences at the centre of nursing interest and practice. It is argued that understanding a disease process should of necessity include an understanding of the concerns of those who live with it. Findings related to the following research questions are discussed: first, what are the challenges of living with diabetes? and second, what are people's perceptions of the nursing care they receive?