Cytokines and their receptors

Real-Time Monitoring and Detection of Single-Cell Level Cytokine Secretion Using LSPR Technology

Cytokine secretion researches have been a main focus of studies among the scientists in the recent decades for its outstanding contribution to clinical diagnostics. Localized surface plasmon resonance (LSPR) technology is one of the conventional methods utilized to analyze these issues, as it could provide fast, label-free and real-time monitoring of biomolecule binding events. However, numerous LSPR-based biosensors in the past are usually utilized to monitor the average performance of cell groups rather than single cells. Meanwhile, the complicated sensor structures will lead to the fabrication and economic budget problems. Thus, in this paper, we report a simple synergistic integration of the cell trapping of microwell chip and gold-capped nanopillar-structured cyclo-olefin-polymer (COP) film for single cell level Interleukin 6 (IL-6) detection. Here, in-situ cytokine secreted from the trapped cell can be directly observed and analyzed through the peak red-shift in the transmittance spectrum. The fabricated device also shows the potential to conduct the real-time monitoring which would greatly help us identify the viability and biological variation of the tested single cell.

The Cytokine Network: Their Role in Physiopathology and Therapeutic Implications

Lymphocytes, accessory-endothelial-and inflammatory-cells produce a variety of soluble factors termed cytokines. These are regulatory molecules which appear after the immune response at all stages of lymphocyte development. They also have important regulatory influences on other haematopoietic cells. Rapid progress is being made through the use of gene cloned cytokines in understanding the complex interactions of these factors with many different cell types. New factors have been added to the cytokine network, and new functions reported for existing cytokines. The clinical implications in disease and the application of cytokines or their inhibitors in human disorders, cancer, infection and autoimmunity, has met with some success and many trials are currently in progress which should lead to more successful therapeutic strategies.

Biological correlates of tinnitus-related distress: an exploratory study

During the process of tinnitus diagnostics, various psychometric instruments are used to measure tinnitus-related distress. The aim of present work was to explore whether candidates for biological correlates of the tinnitus-related distress could be found in peripheral blood of patients and if so, whether there was association between them and psychometric scores that reflect tinnitus-related distress. The concentrations of interleukin-1β (IL1β), interleukin-6 (IL6), tumor necrosis factor-α (TNFα) and a brain-derived neutrotrophic factor (BDNF) were measured in serum of 30 patients diagnosed with chronic tinnitus and tested for correlation with psychometric scores collected on the same day. Spearman's correlation analyses detected significant positive association between the concentrations of tumor necrosis factor α and tinnitus loudness, total perceived stress, tension and depression and a negative association between tumor necrosis factor α and a psychometric score "joy". Concentrations of interleukin-1β correlated with the awareness grade of tinnitus. The correlation between visual analogue scale (VAS) "loudness" and tumor necrosis factor α as well as between "joy" and tumor necrosis factor α retained their significance (p < 0.00167) after the application of Bonferroni correction for multiple testing. Partial correlations removing the effects of age, hearing loss and the duration of tinnitus verified the results obtained using Spearman correlation. We conclude that measuring the concentrations of selected circulating cytokines could possibly become an additional objective element of tinnitus diagnostics in the future.

Integrated nanoplasmonic sensing for cellular functional immunoanalysis using human blood

Localized surface plasmon resonance (LSPR) nanoplasmonic effects allow for label-free, real-time detection of biomolecule binding events on a nanostructured metallic surface with simple optics and sensing tunability. Despite numerous reports on LSPR bionanosensing in the past, no study thus far has applied the technique for a cytokine secretion assay using clinically relevant immune cells from human blood. Cytokine secretion assays, a technique to quantify intercellular-signaling proteins secreted by blood immune cells, allow determination of the functional response of the donor's immune cells, thus providing valuable information about the immune status of the donor. However, implementation of LSPR bionanosensing in cellular functional immunoanalysis based on a cytokine secretion assay poses major challenges primarily owing to its limited sensitivity and a lack of sufficient sample handling capability. In this paper, we have developed a label-free LSPR biosensing technique to detect cell-secreted tumor necrosis factor (TNF)-α cytokines in clinical blood samples. Our approach integrates LSPR bionanosensors in an optofluidic platform that permits trapping and stimulation of target immune cells in a microfluidic chamber with optical access for subsequent cytokine detection. The on-chip spatial confinement of the cells is the key to rapidly increasing a cytokine concentration high enough for detection by the LSPR setup, thereby allowing the assay time and sample volume to be significantly reduced. We have successfully applied this approach first to THP-1 cells and then later to CD45 cells isolated directly from human blood. Our LSPR optofluidics device allows for detection of TNF-α secreted from cells as few as 1000, which translates into a nearly 100 times decrease in sample volume than conventional cytokine secretion assay techniques require. We achieved cellular functional immunoanalysis with a minimal blood sample volume (3 μL) and a total assay time 3 times shorter than that of the conventional enzyme-linked immunosorbent assay (ELISA).

Inositol lipids and phosphates in the proliferation and differentiation of lymphocytes and myeloid cells

It is established that receptor-stimulated hydrolysis of phosphatidylinositol 4,5-bisphosphate is an essential signalling reaction in the responses of many haemopoietic cells to stimuli: examples include platelet activation, antigen-driven initiation of cell proliferation in mature B and T lymphocytes and histamine release by mast cells, and chemotaxis and oxygen radical generation by neutrophils. However, the roles of inositol lipids and phosphates in the development of haemopoietic and immune cells are less well understood. This paper discusses three such situations: the sequential employment of phosphatidylinositol 4,5-bisphosphate hydrolysis and cyclic AMP accumulation as two signals essential to the action of the B lymphocyte-stimulatory cytokine interleukin 4; the involvement of antigen receptor-triggered inositol lipid hydrolysis in apoptotic elimination of immature anti-self T lymphocytes in the fetal mouse thymus; and the possible role of changes in the levels of abundant inositol polyphosphates in the differentiation of HL-60 promyelocytic cells and of normal human myeloid blast cells.

Hollow-spheres: a new model for analyses of differentiation of pancreatic duct epithelial cells

We discovered a unique feature of a subclone of the pancreatic carcinoma cell line A818. A818-1-derived hollow-spheres developed under three-dimensional growth conditions. Hollow-spheres consist of a single layer of 50-200 epithelial cells surrounding an inner lumen. In contrast to A818-1, the subclone A818-4 and all other pancreatic tumor cell lines tested (n = 5), formed spheroids as the only three-dimensional phenotype. A dramatically reduced proliferation rate compared to the corresponding monolayer was observed in hollow-spheres when bromodeoxyuridine (BrdU) incorporation was measured. This finding was confirmed by immunostaining using the MIB-1 antibody. Mechanically disrupted hollow-spheres not only attached but also grew as monolayer with the same doubling time as the founder cells. Hollow-spheres developed in fetal calf serum (FCS) containing RPMI 1640 medium without additionally added cytokines. A818-1 hollow-sphere formation and integrity was influenced by interferon-gamma. Tumor necrosis factor-alpha (TNF-alpha) led to cell death. Exogenously added hepatocyte growth factor (HGF) showed no effect neither on hollow-sphere formation nor on the integrity of completely developed hollow-spheres. Moreover, no changes were observed when cells were treated with a neutralizing antibody for HGF. Interestingly, hollow-spheres showed intensive immunoreactivity for the HGF-receptor (c-met) and its ligand (HGF). Immunostaining for the biliary glycoprotein (BGP), the non-specific cross-reacting antigen 95 (NCA95) and beta-catenin revealed a polar organization of hollow-spheres. Immunhistochemically, hollow-spheres were negative for the carcinoembryonic antigen (CEA). When hollow-spheres were embedded into matrigel, duct-like tubes grew out. Taken together, A818-1 hollow-spheres resemble normally differentiated duct-like structures and will serve as an excellent model to study differentiation of human pancreatic epithelial cells.

Effect of cell cycle on the regulation of the cell surface and secreted forms of type I and type II human tumor necrosis factor receptors

The cell cycle has been shown to regulate the biological effects of human tumor necrosis factor (TNF), but to what extent that regulation is due to the modulation of TNF receptors is not clear. In the present report we investigated the effect of the cell cycle on the expression of surface and soluble TNF receptors in human histiocytic lymphoma U-937. Exposure to hydroxyurea, thymidine, etoposide, bisbensimide, and demecolcine lead to accumulation of cells primarily in G1/S, S, S/G2/M, G2/M, and M stages of the cell cycle, respectively. While no significant change in TNF receptors occurred in cells arrested in G1/S or S/G2 stages, about a 50% decrease was observed in cells at M phase of the cycle. Scatchard analysis showed a reduction in receptor number rather than affinity. In contrast, cells arrested at S phase (thymidine) showed an 80% increase in receptor number. The decrease in the TNF receptors was not due to changes in cell size or protein synthesis. The increase in receptors, however, correlated with an increase in total protein synthesis (to 3.8-fold of the control levels). A proportional change was observed in the p60 and p80 forms of the TNF receptors. A decrease in the surface receptors in cells arrested in M phase correlated with an increase in the amount of soluble receptors. The cellular response to TNF increased to 8- and 2-fold in cells arrested in G1 and S phase, respectively; but cells at G2/M phase showed about 6-fold decrease in response. In conclusion, our results demonstrate that the cell cycle plays an important role in regulation of cell-surface and soluble TNF receptors and also in the modulation of cellular response.

Aspartate receptors of Escherichia coli and Salmonella typhimurium bind ligand with negative and half-of-the-sites cooperativity

The aspartate receptors of Escherichia coli and Salmonella typhimurium which mediate chemotactic responsiveness to aspartate have 79% amino acid sequence identity but exhibited apparently quite different aspartate binding plots. The Scatchard plot of the Salmonella receptor was concave upward whereas the E. coli receptor gave a straight line. Because the two binding sites in the Salmonella receptor lacking aspartate have a 2-fold crystallographic symmetry axis and do not overlap, the observation of more than one class of binding sites must be due to a ligand-induced conformational change giving negative cooperativity. The closely related E. coli receptor was found to bind with only one class of sites but with a stoichiometry of one aspartate per dimer. The E. coli receptor thus binds with half-of-sites reactivity, an extreme form of negative cooperativity in which the second ligand is not observed to bind at all. Comparison of the X-ray crystal structure of the ligand binding domain with and without bound aspartate revealed ligand-induced conformational changes that explain the two examples of negative cooperativity.

Intestinal epithelial function: the case for immunophysiological regulation. Implications for disease (2)

Substantial amounts of data have been reported showing a role for immunomodulation of epithelial function (particularly ion secretion and permeability) using animal models of anaphylactic reactions. In part one of this review we outlined the main immune cell types and mediators/cytokines that are currently known to influence epithelial physiology either directly, or indirectly via an intermediate cell type. Here we will expand on the significance of these studies and show how antigenic activation of the mucosal immune system can evoke changes in epithelial function that may be beneficial to the host by mediating loss/inactivation of the antigen. However, a continued and inappropriate immune stimulation can lead to pathophysiological reactions and disease. Thus, we will present data on immune regulation of epithelial function with direct applicability to understanding the mechanism underlying human intestinal inflammatory and secretory disease. Finally, we highlight key strategic points in the cascade of immune events that can control epithelial function and thus may be of relevance in the formulation of new therapeutic approaches to intestinal inflammation.