Function of hesperidin alleviating inflammation and oxidative stress responses in COPD mice might be related to SIRT1/PGC-1α/NF-κB signaling axis.

Purpose: Hesperidin has anti-inflammatory and anti-oxidant stress effects, but its functions in chronic obstructive pulmonary disease (COPD) remains unknown. This study analyzed the role of hesperidin in COPD mice, aiming to provide a basis for the hesperidin application.Materials and methods: Mice were injected with cigarette smoke extract (CSE) to construct COPD models and then treated with budesonide or hesperidin. Hematoxylin-eosin (HE) and TUNEL assays were used to observe the pathological changes and cell death of lung tissue. The levels of interleukin (IL)-6, IL-8, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) in bronchoalveolar lavage fluid (BLAF), as well as myeloperoxidase (MPO) content in lung tissues were confirmed. The expression levels of SIRT1, PGC-1α, and p65 proteins were measured by western blotting (WB) analysis.Results: CSE induced inflammatory cell infiltration and cell death in the lung tissues of mice, whereas budesonide and hesperidin effectively alleviated these pathological changes. The levels of IL-6, IL-8, and MDA in BLAF and pulmonary MPO content in the COPD mice were effectively increased, while the levels of SOD and CAT in BLAF were decreased, which could be reversed by budesonide and hesperidin. Moreover, the addition of budesonide or hesperidin reliably accelerated the expression levels of PGC-1α and SIRT1 but suppressed the phosphorylation of p65 in COPD mice. In general, high-dose hesperidin had a stronger regulatory effect on COPD mice.Conclusions: Hesperidin alleviated inflammation and oxidative stress responses in CES-induced COPD mice, associated with SIRT1/PGC-1α/NF-κB signaling axis, which might become a new direction for COPD treatment.

Improving the Sensitivity of Fluorescence-Based Immunoassays by Photobleaching the Autofluorescence of Magnetic Beads.

In fluorescence-based assays, usually a target molecule is captured using a probe conjugated to a capture surface, and then detected using a second fluorescently labeled probe. One of the most common capture surfaces is a magnetic bead. However, magnetic beads exhibit strong autofluorescence, which often overlaps with the emission of the reporter fluorescent dyes and limits the analytical performance of the assay. Here, several widely used magnetic beads are photobleached and their autofluorescence is reduced to 1% of the initial value. Their autofluorescence properties, including their photobleaching decay rates and autofluorescence spectra pre- and post-photobleaching, and the stability of the photobleaching over a period of two months are analyzed. The photobleached beads are stable over time and their surface functionality is retained. In a high-sensitivity LX-200 system using photobleached magnetic beads, human interleukin-8 is detected with a threefold improvement in detection limit and signal-to-noise ratio over results achievable with nonbleached beads. Since many contemporary immunoassays rely on magnetic beads as capture surfaces, prebleaching the beads may significantly improve the analytical performance of these assays. Moreover, nonmagnetic beads with low autofluorescence are also successfully photobleached, suggesting that photobleaching can be applied to various capture surfaces used in fluorescence-based assays.

A rapid and efficient way to obtain modified chemokines for functional and biophysical studies.

Chemokines and their receptors control cell migration associated with routine immune surveillance, inflammation and development. They are also implicated in a large number of inflammatory diseases, cancer and HIV. Here we describe a rapid and efficient way to express and purify milligram quantities of multiple chemokine ligands (CCL7/MCP-3, CCL14/HCC-1, CCL3/MIP-1α and CXCL8/IL-8) containing C-terminal modifications to enable coupling to fluorescent dyes or small molecules such as biotin, in vitro. These labeled chemokines display wild-type behavior in both receptor binding and calcium mobilization assays. The ability to rapidly and inexpensively produce labeled chemokines opens the way for their use in many applications, including non-traditional chemokine-receptor interaction studies, both on intact cells and with purified receptor reconstituted in artificial membranes in vitro. Furthermore, the ability to immobilize chemokines to obtain ligand affinity columns aids in efforts to purify chemokine receptors for structural and biophysical studies, by facilitating the separation of functional proteins from their non-functional counterparts.

A highly efficient method for the production and purification of recombinant human CXCL8.

Chemokines play diverse and fundamental roles in the immune system and human disease, which has prompted their structural and functional characterisation. Production of recombinant chemokines that are folded and bioactive is vital to their study but is limited by the stringent requirements of a native N-terminus for receptor activation and correct disulphide bonding required to stabilise the chemokine fold. Even when expressed as fusion proteins, overexpression of chemokines in E. coli tends to result in the formation of inclusion bodies, generating the additional steps of solubilisation and refolding. Here we present a novel method for producing soluble chemokines in relatively large amounts via a simple two-step purification procedure with no requirements for refolding. CXCL8 produced by this method has the correct chemokine fold as determined by NMR spectroscopy and in chemotaxis assays was indistinguishable from commercially available chemokines. We believe that this protocol significantly streamlines the generation of recombinant chemokines.

A proinflammatory activity of interleukin 8 in human skin: expression of the inducible nitric oxide synthase in psoriatic lesions and cultured keratinocytes.

Psoriasis is a common chronic skin disease mediated by cellular immune mechanisms and characterized by an intense neutrophil cell infiltrate and proliferative activation of epidermal keratinocytes. We have previously described the expression of the inducible nitric oxide synthase (iNOS) in epidermal keratinocytes of psoriatic skin lesions. In this study, the role of iNOS in psoriatic inflammation was explored ex vivo in psoriatic skin biopsies and in vitro in primary cultures of human keratinocytes. Messenger RNA for the iNOS enzyme (iNOS mRNA) was detected by reverse transcriptase polymerase chain reaction in skin biopsies from patients with psoriasis, but not in skin specimens from patients with atopic eczema or from healthy volunteers. As demonstrated by in situ hybridization and immunohistochemistry, expression of iNOS mRNA and its gene product was localized to the epidermal keratinocytes of psoriatic skin lesions. In situ hybridization further revealed a complete colocalization of mRNA expression for iNOS with interleukin (IL) 8 receptor-specific mRNA either in the basal germinative cell layer or at focal sites of ongoing neutrophil inflammation in suprabasal cell layers. Because psoriatic keratinocytes have previously been shown to express mRNA transcripts for IL-8, it seemed reasonable to hypothesize that iNOS expression could be induced in an autocrine loop by IL-8. This hypothesis was substantiated by our in vitro experiments showing that a combination of IL-8 and interferon gamma induces the expression of iNOS-specific mRNA and of the functional enzyme in cultured human keratinocytes. These results suggest an important role for iNOS in concert with IL-8 and its receptor early during the formation of psoriatic lesions.

A Simple and Efficient System for Producing Recombinant Human CXCL8 in Escherichia coli.

Multifunctional pro-inflammatory cytokine CXCL8 is a small peptide of 8-10 kDa in size and it functions as a monomer or dimer. CXCL8 harbors 2 disulfide bonds for its stability. Although production of the CXCL8 protein in a large quantity in both mammalian and bacterial systems has been reported, the processes are complicated and lengthy. Here, we develop a new bacterial expression system for recombinant CXCL8 and simplify the purification system to yield a high amount of protein quickly. The purified CXCL8 protein from our new system develops a crystal structure that is identical to that produced through the mammalian expression system. Thus, we have established a simple and efficient recombinant CXCL8-producing system, which can be easily operated and is suitable to those requiring a large quantity of CXCL8.

Practitioner empathy and the duration of the common cold.

OBJECTIVE: This study's objective was to assess the relationship of empathy in medical office visits to subsequent outcomes of the common cold. METHODS: A total of 350 subjects ? 12 years of age received either a standard or enhanced physician visit as part of a randomized controlled trial. Enhanced visits emphasized empathy on the part of the physician. The patient-scored Consultation and Relational Empathy (CARE) questionnaire assessed practitioner-patient interaction, especially empathy. Cold severity and duration were assessed from twice-daily symptom reports. Nasal wash was performed to measure the immune cytokine interleukin-8 (IL-8). RESULTS: Eighty-four individuals reported perfect (score of 50) CARE scores. They tended to be older with less education but reported similar health status, quality of life, and levels of optimism. In those with perfect CARE scores, cold duration was shorter (mean 7.10 days versus 8.01 days), and there was a trend toward reduced severity (mean area under receiver-operator characteristics curve 240.40 versus 284.49). After accounting for possible confounding variables, cold severity and duration were significantly lower in those reporting perfect CARE scores. In these models, a perfect score also correlated with a larger increase in IL-8 levels. CONCLUSIONS: Clinician empathy, as perceived by patients with the common cold, significantly predicts subsequent duration and severity of illness and is associated with immune system changes.

Plasmonic droplet screen for single-cell secretion analysis.

Single-cell secretion analysis technologies are needed to elucidate the heterogeneity of cellular functionalities. Although ligand binding assays in microwells provide a promising approach for measuring single-cell secretions, their throughput is limited. Recently, droplet assays have been developed for high-throughput single-cell screening. However, because washing steps are difficult to perform with droplets, there are still challenges in measuring secretions using droplet assays. In this study, a plasmonic droplet screen approach is developed for one-step washing-free multiplex detection of single-cell secretions. Individual cells are encapsulated with antibody-conjugated gold nanorods (AuNRs) in droplets to evaluate their secretion levels. The shift in the plasmon resonance peak reflects the amount of secreted protein without needing additional indicator and washing steps. The plasmonic signals from a continuous flow of single-cell droplets are collected by dark-field spectroscopy (∼100-150 cells min-1). This platform is tested by screening interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) secreted from suspended leukemia cells and adherent breast cancer cells. Overall, this novel strategy shows the potential and flexibility of high-efficiency multiplex single-cell secretion analysis.

The biological effects of rainbow trout (Oncorhynchus mykiss) recombinant interleukin-8.

In this report, recombinant interleukin-8 (rIL-8) was produced and its activity tested for the first time in fish. The rainbow trout rIL-8 was produced in Escherichia coli and purified using a 6xHis tag at the N-terminus. The rIL-8 induced a dose-dependent migration of head kidney leukocytes at concentrations from 0.1 to 10 ng/ml, with a peak response at 1 ng/ml. Trout rIL-8 also had a significant effect on superoxide production by head kidney cells, with maximal activity at 0.1 and 1 ng/ml. When injected intraperitoneally into trout, rIL-8 had a clear effect on total leukocyte number in the peritoneal cavity, with increasing doses (up to 5 microg) eliciting more cells. Of three leukocyte types distinguished, neutrophils were the dominant cell type, especially at higher rIL-8 concentrations. In contrast, the proportion of macrophages and lymphocytes decreased with rIL-8 administration, suggesting that they were not attracted at the same rate as neutrophils.

A new protocol for high-yield purification of recombinant human CXCL8((3-72))K11R/G31P expressed in Escherichia coli.

The ELR-CXC chemokines are important to neutrophil inflammation in many acute and chronic diseases. Among them, CXCL8 (interleukin-8, IL-8), binds to both the CXCR1 and CXCR2 receptors with high affinity and the expression levels of CXCL8 are elevated in many inflammatory diseases. Recently, an analogue of human CXCL8, CXCL8((3-72))K11R/G31P (hG31P) has been developed. It has been demonstrated that hG31P is a high affinity antagonist for both CXCR1 and CXCR2. To obtain large quantities of hG31P, we have successfully constructed and expressed hG31P in Escherichia coli. Moreover, we have developed a new protocol for high-yield purification of hG31P and for the removal of lipopolysaccharide (LPS, endotoxin) associated with hG31P due to the expression in E. coli. The purity of hG31P is more than 95% and the final yield is 9.7mg hG31P per gram of cell paste. The purified hG31P was tested by various biological assays. In addition, the structural properties of hG31P were studied by circular dichroism (CD), ultracentrifuge, isothermal titration calorimetry (ITC), and nuclear magnetic resonance (NMR) spectroscopy. Our results indicate that this purification protocol is very simple and easy to amplify at a large scale. The results of this study will provide an effective route to produce enough hG31P for future clinical studies.

Cloning and expression analysis of two pro-inflammatory cytokines, IL-1 beta and IL-8, in haddock (Melanogrammus aeglefinus).

This paper reports the cloning and sequencing of two pro-inflammatory cytokines, interleukin (IL)-1beta and IL-8, in haddock (Melanogrammus aeglefinus) by homology cloning. The complete transcript of the haddock IL-1beta was sequenced and contained 1043 bp, including a 762 bp open reading frame. The 3' end of the gene includes a polyadenylation signal 13 bp upstream of the poly(A) tail, along with 10 instability motifs. The predicted protein of 253aa revealed the presence of the IL-1 family signature and the absence of an ICE cut site. The cDNA of the chemokine IL-8 was sequenced in haddock and contained 903 bp of which 306 bp are the open reading frame. Interestingly, the predicted protein sequence of 101aa, contains an ELR motif preceding the CXC signature, common in all vertebrate IL-8 molecules but absent in all teleost genes sequenced to date. The expression of both haddock cytokines was studied in four different tissues: head kidney, spleen, liver and gill. Tissues were obtained from both healthy fish and fish stimulated in vivo with four commercial serotypes of LPS, namely Escherichia coli 026:B6, 055:B5, 0111:B4 and 0127:B8 and PMA. Haddock IL-1beta was not constitutively expressed and expression was only observed following stimulation. However, this expression was stimulant dependent and only PMA and LPS 026:B6 induced high levels of expression in the head kidney. The haddock IL-8 gene on the other hand, showed a constitutive expression, that could be up or down-regulated depending on the immunostimulant used, although to a lesser extent than IL-1beta.

A dual-functional microfluidic chip for on-line detection of interleukin-8 based on rolling circle amplification.

Interleukin 8 (IL-8), also known as C-X-C motif ligand 8(CXCL8), is a proinflammatory chemokine functioned in neutrophil chemotaxis and activation. And it plays an important role in the process of glioma stem-like cell vascularization in the latest research. Herein, a dual-function microfluidic biosensor based on rolling circle amplification (RCA) was fabricated for cell culture and online IL-8 detection. A microfluidic chip was designed with two high passages connected by the vertical channels. One of the channels with immobilized capture antibody was prepared for IL-8 detection and another channel for cell culture. Immunoassays were achieved by a sandwich structure consisting of antibodies, IL-8, and aptamers. Signal amplification was mainly due to RCA and biotin-streptavidin linkage. The linear range for IL-8 was 7.5 -120pgmL-1 in this assay. Moreover, the developed method was successfully applied to detect the IL-8 in tumor-derived endothelial cells (TDEC) and Human Umbilical Vein Endothelial cells (HUVEC) under chemical hypoxia condition. Semi-quantitative detection of IL-8 consumption in HUVEC cells in low oxygen condition was also achieved. These results were in statistical agreement with those obtained by commercial assay of enzyme-linked immunoassay kit (ELISA). The microfluidic chip based biosensor reported hereby has a large prospect in the basic research and clinical diagnosis of cancer stem cell.

Chemokine expression during hepatic ischemia/reperfusion-induced lung injury in the rat. The role of epithelial neutrophil activating protein.

The liver is highly susceptible to a number of pathological insults, including ischemia/reperfusion injury. One of the striking consequences of liver injury is the associated pulmonary dysfunction that may be related to the release of hepatic-derived cytokines. We have previously employed an animal model of hepatic ischemia/reperfusion injury, and demonstrated that this injury causes the production and release of hepatic-derived TNF, which mediates a neutrophil-dependent pulmonary microvascular injury. In this study, we have extended these previous observations to assess whether an interrelationship between TNF and the neutrophil chemoattractant/activating factor, epithelial neutrophil activating protein-78 (ENA-78), exists that may be accountable for the pathology of lung injury found in this model. In the context of hepatic ischemia/reperfusion injury, we demonstrated the following alterations in lung pathophysiology: (a) an increase in pulmonary microvascular permeability, lung neutrophil sequestration, and production of pulmonary-derived ENA-78; (b) passive immunization with neutralizing TNF antiserum resulted in a significant suppression of pulmonary-derived ENA-78; and (c) passive immunization with neutralizing ENA-78 antiserum resulted in a significant attenuation of pulmonary neutrophil sequestration and microvascular permeability similar to our previous studies with anti-TNF. These findings support the notion that pulmonary ENA-78 produced in response to hepatic-derived TNF is an important mediator of lung injury.

Monomer-dimer equilibria of interleukin-8 and neutrophil-activating peptide 2. Evidence for IL-8 binding as a dimer and oligomer to IL-8 receptor B.

By chemical cross-linking experiments we show that at physiologically relevant concentrations IL-8 and NAP-2 monomers are in an equilibrium with dimers and even oligomers (KD approximately 300-800 nM). Oligomerization seems to be more prevalent for IL-8 than for NAP-2. The form in which IL-8 and NAP-2 bind to their specific receptors was analyzed in binding experiments with COS-1 cells expressing IL-8 receptor A or B in recombinant forms. Both receptors were cloned from the human myeloid leukemic cell line AML-193. Type A receptor had high affinity for IL-8 (KD approximately 4 nM) and low affinity for NAP-2 (KD > or = 700 nM), whereas the type B receptor was of equally high affinity (KD approximately 2 nM) for both IL-8 and NAP-2. However, IL-8 receptor B could bind specifically three to four times more IL-8 than NAP-2, and NAP-2 was a weak competitor for IL-8 binding to the same receptor. In addition, IL-8, but not NAP-2, could be cross-linked to dimers when bound to IL-8 receptor B. We suggest from these findings that IL-8, but not NAP-2, binds as a dimer and oligomer to IL-8 receptor.

Characterization of Adsorbents for Cytokine Removal from Blood in an In Vitro Model.

INTRODUCTION: Cytokines are basic targets that have to be removed effectively in order to improve the patient's health status in treating severe inflammation, sepsis, and septic shock. Although there are different adsorbents commercially available, the success of their clinical use is limited. Here, we tested different adsorbents for their effective removal of cytokines from plasma and the resulting effect on endothelial cell activation. METHODS: The three polystyrene divinylbenzene (PS-DVB) based adsorbents Amberchrom CG161c and CG300m and a clinically approved haemoperfusion adsorbent (HAC) were studied with regard to cytokine removal in human blood. To induce cytokine release from leucocytes, human blood cells were stimulated with 1 ng/ml LPS for 4 hours. Plasma was separated and adsorption experiments in a dynamic model were performed. The effect of cytokine removal on endothelial cell activation was evaluated using a HUVEC-based cell culture model. The beneficial outcome was assessed by measuring ICAM-1, E-selectin, and secreted cytokines IL-8 and IL-6. Additionally the threshold concentration for HUVEC activation by TNF-α and IL-1ß was determined using this cell culture model. RESULTS: CG161c showed promising results in removing the investigated cytokines. Due to its pore size the adsorbent efficiently removed the key factor TNF-α, outperforming the commercially available adsorbents. The CG161c treatment reduced cytokine secretion and expression of cell adhesion molecules by HUVEC which underlines the importance of effective removal of TNF-α in inflammatory diseases. CONCLUSION: These results confirm the hypothesis that cytokine removal from the blood should approach physiological levels in order to reduce endothelial cell activation.

Detection of intracellular interleukin-8 in human mast cells: flow cytometry as a guide for immunoelectron microscopy.

The chemokine interleukin-8 (IL-8) mediates infiltration and adhesion of neutrophils during inflammatory processes. We have previously shown that this cytokine can be produced and released by normal and leukemic human mast cells (HMC-1 cells). To assess whether and to what extent this cytokine is stored intracellularly, we investigated production and localization of IL-8 at the single-cell level by combined use of flow cytometry (FACS) and immunoelectron microscopy. Conditions necessary for optimal fixation and permeabilization of HMC-1 cells were determined by measuring changes in cell-specific light scatter parameters and by estimating cellular uptake of propidiumiodide (PI). In this way, we were able to detect IL-8 with a monoclonal antibody in stimulated cells that were microwave-fixed with a combination of paraformaldehyde (4%) and glutaraldehyde (0.1%), followed by permeabilization with saponin (0.025%). FACS analysis revealed time-dependent synthesis of IL-8 with at most 50% positively stained cells at 8-12 hr after stimulation. For pre-embedding immunogold electron microscopy, cells were treated according to the protocol established by flow cytometry. IL-8 was found to be located in specific cytoplasmic, electron-dense granules of stimulated HMC-1 cells. These results confirm and extend our previous findings by demonstrating IL-8 expression in HMC-1 cells at the single-cell level. In addition, we propose that quantitative FACS can be reliably used in a timesaving manner to establish appropriate conditions for pre-embedding immunoelectron microscopy of intracellular antigens.

Isolation and amino acid sequence of a chemotactic protein, LECT/interleukin 8, from a human myeloid leukemia cell line, ML-1.

We looked for chemotaxin/interleukin 8 (CT/IL-8) activity in the culture fluids of 97 human leukemia cell lines and found it in two of the T cell lines, six of the myeloid cell lines, and one of the normal B-cell lines. It was particularly strong in the culture fluids of two cell lines. These cell lines secreted a chemotactic protein into the culture fluids under certain conditions of stimulation with phorbol-12-myristate 13-acetate (PMA), lipopolysaccharide, or hemagglutinin-P. A myeloid leukemia cell line, ML-1, secreted an inducible chemotaxin when stimulated with PMA (1 ng/ml) for 24 h. We purified the chemotaxin from ML-1 cell culture fluid using an improved procedure: concentration with DEAE-Sepharose CL-6B and CM-Sepharose CL-6B, CM-Sepharose column chromatography, and reverse-phase 5TMS-300 column on HPLC with the retention time coinciding with that of LUCT/IL-8 [Suzuki et al., 1989, J. Exp. Med. 169, 1895]. The yield was 200 micrograms protein from 6 liters of the culture fluid. The N terminus of CT/IL-8 was AVLPR-SAKELRXQXIKTYSK- - -, the same as that of LUCT/IL-8, which is constitutively secreted from lung giant cell carcinoma LU65C cells. The optimal concentration in the chemotactic activity of CT/IL-8, equivalent to that of bacterial chemotactic peptide fMet-Leu-Phe (10 nM), was found to be 5 nM. The results show that this chemotaxin is identical to LUCT/IL-8.

Changes in growth factor levels in human wound fluid.

BACKGROUND: It has been suggested that platelet-derived growth factor (PDGF) plays a central role in wound healing. Analysis of human wound fluid revealed the presence of PDGF AA (30 kd) and monocyte/macrophage-derived growth factor (MDGF) (12 to 14 kd) in the immediate postoperative period. METHODS: The amount of PDGF AA present was assayed by Western blot analysis. The chemotactic and mitogenic potential of purified wound fluid containing PDGF AA and MDGF was determined on a responsive cell line. The biologic activity of MDGF was assayed with a cell line that is unresponsive to the PDGF AA found in wound fluid. RESULTS: Both the concentration and the biologic activity were highest in the immediate postoperative period and declined to negligible levels by 24 hours after surgery. The chemotactic activity of MDGF was highest in the immediate postoperative period and declined during the first 24 hours in a manner similar to that of the combined PDGF AA and MDGF activity. CONCLUSIONS: These data demonstrate the changing levels of PDGF and MDGF in human wound fluid over time, supporting the cascade model of wound repair. By demonstrating that MDGF acts on cell lines unresponsive to the PDGF AA found in wound fluid, these data suggest that MDGF may also play an important role in wound healing.