Development of cell-based assays for cytokine receptor signaling, using an AlphaScreen SureFire assay format

Immortalized human myoblast cell lines for the delivery of therapeutic proteins using encapsulated cell technology

Despite many promising results obtained in previous preclinical studies, the clinical development of encapsulated cell technology (ECT) for the delivery of therapeutic proteins from macrocapsules is still limited, mainly due to the lack of an allogeneic cell line compatible with therapeutic application in humans. In our work, we generated an immortalized human myoblast cell line specifically tailored for macroencapsulation. In the present report, we characterized the immortalized myoblasts and described the engineering process required for the delivery of functional therapeutic proteins including a cytokine, monoclonal antibodies and a viral antigen. We observed that, when encapsulated, the novel myoblast cell line can be efficiently frozen, stored, and thawed, which limits the challenge imposed by the manufacture and supply of encapsulated cell-based therapeutic products. Our results suggest that this versatile allogeneic cell line represents the next step toward a broader development and therapeutic use of ECT.

Gene profiles to characterize the combined toxicity induced by low level co-exposure of silica nanoparticles and benzo[a]pyrene using whole genome microarrays in zebrafish embryos

Several studies have suggested that air pollutants combine exposure have greater adverse effects. However, limited studies were available on the combined toxicity of silica nanoparticles (SiNPs) and benzo[a]pyrene (B[a]P). The study was to evaluate the toxic effect and mechanisms of low-dose exposure of SiNPs, B[a]P and co-exposure in zebrafish embryos. In this study, zebrafish embryos received intravenous microinjection of SiNPs and B[a]P, and then was used to select differentially expressed genes by microarray analysis. Multiple bioinformatics analyses and STC analysis were done to identify key genes, pathways and biological processes and the expression trend of genes in each group. 1) 3065 differentially expressed genes were identified in zebrafish embryos. 2) These differentially expressed genes were involved in multiple biological processes and cellular processes such as immunity, response to stimuli, cell proliferation, adhesion, signaling transduction, and embryonic development. 3) Dynamic Gene Network analysis was used to identify a subgroup of 26 core genes that involved in multiple biological processes and cellular processes. 4) Pathway analysis and Signal-net analysis indicated that the MAPK signaling pathway, calcium signaling pathway, p53 signaling pathway, PI3k/Akt signaling pathway, and several pathways associated with immune response were the most prominent significant pathways induced by co-exposure of SiNPs and B[a]P in zebrafish embryos. Our study demonstrated that the molecular actions of co-treated with SiNPs and B[a]P on the immune system, inflammatory process and cardiovascular development had more severe toxicity than single exposure.

Inflammatory response and blood hypercoagulable state induced by low level co-exposure with silica nanoparticles and benzo[a]pyrene in zebrafish (Danio rerio) embryos

Given the severe situation of world-wide particulate matter air pollution, it is urgent to explore the combined effects of particulate matter components on cardiovascular system. Using zebrafish model, this study was aimed to determine whether the low level co-exposure to silica nanoparticles (SiNPs) and benzo[a]pyrene (B[a]P) had a pronounced cardiovascular toxicity than the single exposure to either SiNPs or B[a]P alone. The FTIR and TGA analysis showed that the co-exposure system possessed of high absorption and thermal stability. Embryos exposed to SiNPs or B[a]P alone did not show cardiac toxicity phenotype at the NOAEL level. However, embryos co-exposed to SiNPs and B[a]P exhibited pericardial edema and bradycardia. While ROS generation remained unaffected, the co-exposure induced significant neutrophil-mediated inflammation and caused erythrocyte aggregation in caudal vein of embryos. Microarray analysis and STC analysis were performed to screen the cardiovascular-related differential expression genes and the expression trend of genes in each group. The co-exposure of SiNPs and B[a]P significantly enhanced the expression of proinflammatory and procoagulant genes. Moreover, the co-exposure markedly increased the phosphorylated AP-1/c-Jun and induced TF expression, but not NF-κB p65. This study for the first time demonstrated the inflammatory response and blood hypercoagulable state were triggered by the combination of SiNPs and B[a]P at low level exposure.

Fine particulate matter induces vascular endothelial activation via IL-6 dependent JAK1/STAT3 signaling pathway

Exposure to PM2.5 has been strongly linked to endothelial dysfunction. However, the underlying mechanism of PM2.5 on the vascular endothelial function is poorly understood. This study examined the toxic effect and underlying mechanism of PM2.5 on human umbilical vein endothelial cells (HUVECs). Decreased cell viability and increased LDH activity were observed in the PM2.5-treated HUVECs in a dose-dependent manner. The production of ROS, MDA, and the inhibition of SOD activity were also triggered by PM2.5 in HUVECs. In addition, PM2.5 increased the intracellular levels of proinflammatory cytokines (IL-6, TNF-a, IL-1β, IL-8 and CRP), cell adhesion molecules (ICAM-1, VCAM-1) and tissue factor (TF), resulted in endothelial activation. For an in-depth study, the protein levels of IL-6, JAK1 and STAT3 were up-regulated significantly, while the expression of JAK2 and SOCS1 were down-regulated gradually in PM2.5-treated HUVECs in a dose-dependent manner. These results show that PM2.5 triggered endothelial activation via upregulation of the IL-6 dependent JAK1/STAT3 signaling pathway. This will provide new insights into the toxic effects and mechanisms of cardiovascular diseases triggered by ambient air pollution.

Genome-wide transcriptional analysis of silica nanoparticle-induced toxicity in zebrafish embryos

Although silica nanoparticles (SiNPs) have a promising application in biomedical fields, there is still a lack of comprehensive understanding of genome-wide transcriptional analysis. This study aims to clarify the toxic effect and molecular mechanisms of SiNPs in zebrafish embryos based on microarray analysis and bioinformatics analysis. Microarray data analysis demonstrated that SiNP-induced toxicity in zebrafish embryos affected expression of 2515 genes, including 1107 genes that were up-regulated and 1408 genes that were down-regulated. These differentially expressed genes were subjected to bioinformatics analysis for exploring the biological processes triggered by SiNPs in zebrafish embryos. Gene ontology analysis showed that SiNPs caused significant changes in gene expression patterns related to many important functions, including response to stimuli, immune response, cellular processes, and embryonic development. In addition, pathway analysis and Signal-net analysis indicated that the gap junction, vascular smooth muscle contraction, and metabolic pathways, apoptosis, the MAPK signaling pathway, the calcium signaling pathway and the JAK-STAT signaling pathway were the most prominent significant pathways in SiNP-induced toxicity in zebrafish embryos. In addition, the results from qRT-PCR and western blot analysis showed that the IL-6 dependent JAK1/STAT3 signaling pathway was activated by SiNPs in zebrafish embryos. In summary, our data will provide compelling clues for further exploration of SiNP-induced toxicity in zebrafish embryos.

The cellular thermal shift assay for evaluating drug target interactions in cells

Thermal shift assays are used to study thermal stabilization of proteins upon ligand binding. Such assays have been used extensively on purified proteins in the drug discovery industry and in academia to detect interactions. Recently, we published a proof-of-principle study describing the implementation of thermal shift assays in a cellular format, which we call the cellular thermal shift assay (CETSA). The method allows studies of target engagement of drug candidates in a cellular context, herein exemplified with experimental data on the human kinases p38α and ERK1/2. The assay involves treatment of cells with a compound of interest, heating to denature and precipitate proteins, cell lysis, and the separation of cell debris and aggregates from the soluble protein fraction. Whereas unbound proteins denature and precipitate at elevated temperatures, ligand-bound proteins remain in solution. We describe two procedures for detecting the stabilized protein in the soluble fraction of the samples. One approach involves sample workup and detection using quantitative western blotting, whereas the second is performed directly in solution and relies on the induced proximity of two target-directed antibodies upon binding to soluble protein. The latter protocol has been optimized to allow an increased throughput, as potential applications require large numbers of samples. Both approaches can be completed in a day.

Surface coatings of ZnO nanoparticles mitigate differentially a host of transcriptional, protein and signalling responses in primary human olfactory cells

BACKGROUND

Inhaled nanoparticles have been reported in some instances to translocate from the nostril to the olfactory bulb in exposed rats. In close proximity to the olfactory bulb is the olfactory mucosa, within which resides a niche of multipotent cells. Cells isolated from this area may provide a relevant in vitro system to investigate potential effects of workplace exposure to inhaled zinc oxide nanoparticles.

METHODS

Four types of commercially-available zinc oxide (ZnO) nanoparticles, two coated and two uncoated, were examined for their effects on primary human cells cultured from the olfactory mucosa. Human olfactory neurosphere-derived (hONS) cells from healthy adult donors were analyzed for modulation of cytokine levels, activation of intracellular signalling pathways, changes in gene-expression patterns across the whole genome, and compromised cellular function over a 24 h period following exposure to the nanoparticles suspended in cell culture medium.

RESULTS

ZnO nanoparticle toxicity in hONS cells was mediated through a battery of mechanisms largely related to cell stress, inflammatory response and apoptosis, but not activation of mechanisms that repair damaged DNA. Surface coatings on the ZnO nanoparticles mitigated these cellular responses to varying degrees.

CONCLUSIONS

The results indicate that care should be taken in the workplace to minimize generation of, and exposure to, aerosols of uncoated ZnO nanoparticles, given the adverse responses reported here using multipotent cells derived from the olfactory mucosa.

Development and validation of a single-well cell-based assay for the detection of endogenous phosphoproteins

We describe a cellular assay for detection of phosphorylation of endogenous proteins, whereby cells are seeded, treated, and assayed for modulation of phosphorylation in a single microplate well. The procedure is coupled to a rapid, one-wash sandwich enzyme-linked immuno-sorbent assay, enabling results to be obtained within 3-4 h from cell seeding. The assay was tested in two separate cellular systems, namely, HeLa and MCF-7 cells. When using the one-well protocol with Akt phosphorylation as a model, the response to a number of agonists was the same as the response obtained using cells treated in a separate microplate, using a conventional lysate transfer approach. The assay procedure was automated, and quantitative pharmacological data on three known inhibitors of the PI3-kinase signaling pathway was obtained within 4 h from seeding cells, with six dispense steps, and a single wash cycle. Thus, the protocol affords a reliable means of assaying for cellular signaling events in different cell types, and is amenable to automation.

Antibody-recruiting molecules: an emerging paradigm for engaging immune function in treating human disease

Synthetic immunology, the development of synthetic systems capable of modulating and/or manipulating immunological functions, represents an emerging field of research with manifold possibilities. One focus of this area has been to create low molecular weight synthetic species, called antibody-recruiting molecules (ARMs), which are capable of enhancing antibody binding to disease-relevant cells or viruses, thus leading to their immune-mediated clearance. This article provides a thorough discussion of contributions in this area, beginning with the history of small-molecule-based technologies for modulating antibody recognition, followed by a systematic review of the various applications of ARM-based strategies. Thus, we describe ARMs capable of targeting cancer, bacteria, and viral pathogens, along with some of the scientific discoveries that have resulted from their development. Research in this area underscores the many exciting possibilities at the interface of organic chemistry and immunobiology and is positioned to advance both basic and clinical science in the years to come.

Modulation of L-α-lysophosphatidylinositol/GPR55 mitogen-activated protein kinase (MAPK) signaling by cannabinoids

GPR55 is activated by l-α-lysophosphatidylinositol (LPI) but also by certain cannabinoids. In this study, we investigated the GPR55 pharmacology of various cannabinoids, including analogues of the CB1 receptor antagonist Rimonabant®, CB2 receptor agonists, and Cannabis sativa constituents. To test ERK1/2 phosphorylation, a primary downstream signaling pathway that conveys LPI-induced activation of GPR55, a high throughput system, was established using the AlphaScreen® SureFire® assay. Here, we show that CB1 receptor antagonists can act both as agonists alone and as inhibitors of LPI signaling under the same assay conditions. This study clarifies the controversy surrounding the GPR55-mediated actions of SR141716A; some reports indicate the compound to be an agonist and some report antagonism. In contrast, we report that the CB2 ligand GW405833 behaves as a partial agonist of GPR55 alone and enhances LPI signaling. GPR55 has been implicated in pain transmission, and thus our results suggest that this receptor may be responsible for some of the antinociceptive actions of certain CB2 receptor ligands. The phytocannabinoids Δ9-tetrahydrocannabivarin, cannabidivarin, and cannabigerovarin are also potent inhibitors of LPI. These Cannabis sativa constituents may represent novel therapeutics targeting GPR55.

Unexploited therapies in breast and prostate cancer: blockade of the prolactin receptor

Breast and prostate cancers are hormone-sensitive malignancies that afflict millions of women and men. Although prolactin (PRL) is known as a survival factor that supports tumor growth and confers chemoresistance in both cancers, its precise role in these tumors has not been studied extensively. Growth hormone and placental lactogen also bind PRL receptor (PRLR) and mimic some of the actions of PRL. Blockade of the PRLR represents a novel treatment for patients with advanced breast or prostate cancer with limited therapeutic options. This review discusses different approaches for generating PRLR antagonists. Emphasis is placed on technological advances which enable high-throughput screening for small molecule inhibitors of PRLR signaling that could serve as oral medications.