A quick, easy and inexpensive method for the isolation of human peripheral blood monocytes

Altered recruitment of Sp isoforms to HIV-1 long terminal repeat between differentiated monoblastic cell lines and primary monocyte-derived macrophages

Human immunodeficiency virus type 1 (HIV-1) transcription in cells of the monocyte-macrophage lineage is regulated by interactions between the HIV-1 long terminal repeat (LTR) and a variety of host cell and viral proteins. Binding of the Sp family of transcription factors (TFs) to the G/C box array of the LTR governs both basal as well as activated LTR-directed transcriptional activity. The effect of monocytic differentiation on Sp factor binding and transactivation was examined with respect to the HIV-1 LTR. The binding of Sp1, full-length Sp3 and truncated Sp3 to a high affinity HIV-1 Sp element was specifically investigated and results showed that Sp1 binding increased relative to the binding of the sum of full-length and truncated Sp3 binding following chemically-induced monocytic differentiation in monoblastic (U-937, THP-1) and myelomonocytic (HL-60) cells. In addition, Sp binding ratios from PMA-induced cell lines were shown to more closely approximate those derived from primary monocyte-derived macrophages (MDMs) than did ratios derived from uninduced cell lines. The altered Sp binding phenotype associated with changes in the transcriptional activation mediated by the HIV-1 G/C box array. Additionally, analysis of post-translational modifications on Sp1 and Sp3 revealed a loss of phosphorylation on serine and threonine residues with chemically-induced differentiation indicating that the activity of Sp factors is additionally regulated at the level of post-translational modifications (PTMs).

Transgenic Mice Overexpressing PG1 Display Corneal Opacity and Severe Inflammation in the Eye

Antimicrobial peptides (AMPs) are of interest as alternatives to antibiotics or immunomodulators. We generated and characterized the phenotypes of transgenic mice overexpressing protegrin 1 (PG1), a potent porcine cathelicidin. No obvious differences were observed between PG1 transgenic and wild-type mice in terms of growth, development, general behaviour, and the major immune cell population. However, PG1 transgenic mice intranasally infected with Staphylococcus aureus resulted in a reduction in microscopic pulmonary injury, improved clearance of bacteria, and lower proinflammatory cytokine secretion, compared to those of wild-type mice. On the other hand, approximately 25% of PG1 transgenic mice (n = 54/215) showed corneal opacity and developed inflammation in the eye, resulting ultimately in phthisis bulbi. Immunohistochemical analyses revealed that PG1 and its activator, neutrophil elastase, localized to the basal cells of the cornea and glands in eyelids, respectively. In addition, apoptosis indicated by a Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)-positive signal was detected from flat cells of the cornea. Our study suggests that the expression regulation or localization of AMPs such as PG1 is important to prevent their adverse effects. However, our results also showed that the cytotoxic effects of PG1 on cells could be tolerated in animals, except for the eyes.

Isolation, characterisation and phagocytic function of human macrophages from human peripheral blood

Macrophages are among the most important cells of the immune system. Among other functions, they take part in almost all defense actions against foreign bodies and bacteria, being particularly important in infections, wound healing, and foreign body reactions. Considering their importance for the health of the human body, as well as their important role in several diseases, the in vitro studies based on these cells, are a crucial research field. Taking all mentioned into account, this study describes a simple isolation method of human macrophages (MFUM-HMP-001 and MFUM-HMP-002 cell lines) from peripheral blood. For this purpose, the morphology, the viability, and the phagocytotic activity of the isolated cells were tested. The Immunostaining of MFUM-HMP-001 and MFUM-HMP-002 cells confirmed the macrophage cell markers CD68, CD80, and CD163/M130. The phagocytotic activity was marked in both MFUM-HMP-001 and MFUM-HMP-002 cells, as was the phagocytosis of the pHrodo green Escherichia coli bioparticles conjugates, which was enhanced with the addition of lipopolysaccharide. The cells were stable and exhibited good growth. According to our results, both cell lines are useful for the development of novel macrophage cell-based in vitro models.

Assessment of potential biomarkers of atherosclerosis in Indian patients with type 2 diabetes mellitus

Background & objectives:

Various biological markers of subclinical atherosclerosis have been proposed to predict cardiovascular events in patients with diabetes mellitus (DM). However, there are only a few clinical studies assessing the role of invasive biomarkers [CD-36, peroxisome proliferator-activated receptor gamma (PPAR-γ) and YKL-40] in Indian patients with type 2 DM (T2DM). Hence, the present study was conducted to assess protein levels and gene expression of CD-36, PPAR-γ and YKL-40 in patients with T2DM and compare that with hypertensive and healthy controls.

Methods:

All the participants were subjected to medical history, anthropometric measurements and biochemical and biomarker (ELISA and real-time polymerase chain reaction) estimations. The study groups consisted of patients with T2DM (>5 yr) with hypertension (n=55), patients with T2DM (<2 yr) without hypertension (n=28), hypertensive controls (n=31) and healthy controls (n=30).

Results:

Gene expressions of YKL-40 and CD36 were significantly higher in patients with T2DM (>5 yr) with hypertension compared to healthy controls (P=0.006). In addition, a significant increase in serum levels of sCD36, PPAR-γ and YKL-40 was observed in patients with T2DM (>5 yr) with hypertension compared to healthy controls (P< 0.05). Serum levels as well as gene expression of CD36 showed significant correlation with serum levels as well as gene expression of PPAR-γ (ρ=0.45 and ρ=0.51; P< 0.001), respectively.

Interpretation & conclusions:

CD36 and YKL-40 may be potential inflammatory biomarkers for early onset of atherosclerosis in patients with T2DM.

Long-term donors versus non-donor men: Iron metabolism and the atherosclerotic process

BACKGROUND AND AIMS

The increased iron level and the labile iron pool (LIP) in circulating monocytes are connected to a higher frequency of cardiovascular events.

METHODS

The study investigates the relationship between LIP in circulating monocytes and markers of iron metabolism and atherosclerosis (inflammation, oxidative stress, endothelial dysfunction and arterial elasticity) in long-term blood donors and non-donor volunteers.

RESULTS

We found that donors had significantly higher LIP values than the control group (1.89 ± 0.47 μM vs. 1.50 ± 0.41 μM, p = 0.007). Despite the observed tendency for the donor group to have higher blood pressure, cholesterol, glucose and HOMAR-IR (homeostasis model assessment of insulin resistance), the groups did not differ in inflammatory markers, markers of endothelial dysfunction and markers of impaired arterial elasticity. The donor group had significant changes in iron metabolism (higher serum Fe, ceruloplasmin, and TfR/Ft ratio (transferrin receptor/ferritin ratio) and lower hepcidin, ferritin, and CD163), indicating depletion of body iron stores and activation of iron turnover.

CONCLUSIONS

LIP seems to be a good marker of iron turnover activity in these individuals despite the lack of a decrease in the hemoglobin concentration. We did not find a significant correlation between LIP levels and atherosclerosis progression in the two groups. However, further studies are needed to assess long-term donorship as a protective factor against atherosclerosis.

Density separation of quiescent yeast using iodixanol

As yeast are starved of nutrients, they enter G0, a quiescent state. Quiescent yeast (Q) cells retain viability for extended periods of time and resume growth following supplementation of missing nutrients. As such, Q cells have become a valuable model for studying longevity and self-renewal of chronologically aged cells. Traditional isolation of Q cells involves a relatively long centrifugation time through a continuous density gradient. Here, we describe a rapid and cost-effective Q-cell isolation technique that uses a single-density, one-step gradient prepared from media containing iodixanol.

EphA receptors and ephrin-A ligands are upregulated by monocytic differentiation/maturation and promote cell adhesion and protrusion formation in HL60 monocytes

Background

Eph signaling is known to induce contrasting cell behaviors such as promoting and inhibiting cell adhesion/spreading by altering F-actin organization and influencing integrin activities. We have previously demonstrated that EphA2 stimulation by ephrin-A1 promotes cell adhesion through interaction with integrins and integrin ligands in two monocyte/macrophage cell lines. Although mature mononuclear leukocytes express several members of the EphA/ephrin-A subclass, their expression has not been examined in monocytes undergoing during differentiation and maturation.

Results

Using RT-PCR, we have shown that EphA2, ephrin-A1, and ephrin-A2 expression was upregulated in murine bone marrow mononuclear cells during monocyte maturation. Moreover, EphA2 and EphA4 expression was induced, and ephrin-A4 expression was upregulated, in a human promyelocytic leukemia cell line, HL60, along with monocyte differentiation toward the classical CD14⁺⁺CD16⁻ monocyte subset. Using RT-PCR and flow cytometry, we have also shown that expression levels of αL, αM, αX, and β2 integrin subunits were upregulated in HL60 cells along with monocyte differentiation while those of α4, α5, α6, and β1 subunits were unchanged. Using a cell attachment stripe assay, we have shown that stimulation by EphA as well as ephrin-A, likely promoted adhesion to an integrin ligand-coated surface in HL60 monocytes. Moreover, EphA and ephrin-A stimulation likely promoted the formation of protrusions in HL60 monocytes.

Conclusions

Notably, this study is the first analysis of EphA/ephrin-A expression during monocytic differentiation/maturation and of ephrin-A stimulation affecting monocyte adhesion to an integrin ligand-coated surface. Thus, we propose that monocyte adhesion via integrin activation and the formation of protrusions is likely promoted by stimulation of EphA as well as of ephrin-A.

Electronic supplementary material

The online version of this article (doi:10.1186/s12860-017-0144-x) contains supplementary material, which is available to authorized users.

Slanted, asymmetric microfluidic lattices as size-selective sieves for continuous particle/cell sorting

Hydrodynamic microfluidic platforms have been proven to be useful and versatile for precisely sorting particles/cells based on their physicochemical properties. In this study, we demonstrate that a simple lattice-shaped microfluidic pattern can work as a virtual sieve for size-dependent continuous particle sorting. The lattice is composed of two types of microchannels ("main channels" and "separation channels"). These channels cross each other in a perpendicular fashion, and are slanted against the macroscopic flow direction. The difference in the densities of these channels generates an asymmetric flow distribution at each intersection. Smaller particles flow along the streamline, whereas larger particles are filtered and gradually separated from the stream, resulting in continuous particle sorting. We successfully sorted microparticles based on size with high accuracy, and clearly showed that geometric parameters, including the channel density and the slant angle, critically affect the sorting behaviors of particles. Leukocyte sorting and monocyte purification directly from diluted blood samples have been demonstrated as biomedical applications. The presented system for particle/cell sorting would become a simple but versatile unit operation in microfluidic apparatus for chemical/biological experiments and manipulations.

The labile iron pool in monocytes reflects the activity of the atherosclerotic process in men with chronic cardiovascular disease

The study investigates the relationship between the labile iron pool (LIP) in circulating monocytes and markers of iron metabolism, inflammation, oxidative stress, endothelial dysfunction and arterial elasticity in patients with chronic cardiovascular disease and in healthy volunteers. The patients with a history of CVEs had significantly higher LIP values than did the control group (1.94+/-0.46 microM vs. 1.62+/-0.49 microM, p=0.02). Except for the leukocyte number (WBCs), the groups did not differ in other inflammatory markers (CRPus, CD 163, MPO, MMP-1). Similarly, there were no differences in the markers of endothelial dysfunction (ICAM, VCAM, E-selectin, vWF). The CVE group had higher pulse pressures, levels of markers of impaired arterial elasticity (AI, Young´s modulus, pulsatility, stiffness index), IMT values and ABI values. The LIP concentration was significantly correlated with the transferrin receptor/ferritin ratio, hepcidin levels, VFT content and the ABI and ET values. Patients with a history of CVE have significantly higher concentrations of iron in their intracellular LIP in circulating monocytes than do healthy controls. The independent and significant correlation of LIP with markers of the progression of atherosclerosis and arterial stiffness suggests LIP as a possible novel marker of atherosclerotic activity.

Monocyte preseeding leads to an increased implant bed vascularization of biphasic calcium phosphate bone substitutes via vessel maturation

The present study analyzes the influence of the addition of monocytes to a biphasic bone substitute with two granule sizes (400-700 μm and 500-1000 μm). The majority of the added monocytes was detectable as mononuclear cells, while also low amounts of (chimeric) multinucleated giant cells (MNGCs) were found. No increase in the total number of MNGCs was established, but a significantly increased percent vascularization. Altogether, the results show that the added monocytes become involved in the tissue response to a biomaterial without marked changes in the overall reaction. Monocyte addition enables an increased implant bed vascularization especially via induction of vessel maturation and, thus intervenes positively in the healing reaction to a biomaterial. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2928-2935, 2016.

Moderate- and high-intensity exhaustive exercise in the heat induce a similar increase in monocyte Hsp72

This study examined the relationship between exhaustive exercise in the heat at moderate and high intensities on the intracellular heat shock protein 72 (iHsp72) response. Twelve male subjects cycled to exhaustion at 60 and 75% of maximal oxygen uptake in hot conditions (40 °C, 50% RH). iHsp72 concentration was measured in monocytes before, at exhaustion and 24 h after exercise. Rectal temperature, heart rate and oxygen uptake were recorded during exercise. Volitional exhaustion occurred at 58.9 ± 12.1 and 27.3 ± 9.5 min (P < 0.001) and a rectal temperature of 39.8 ± 0.4 and 39.2 ± 0.6 °C (P = 0.002), respectively, for 60 and 75 %. The area under the curve above a rectal temperature of 38.5 °C was greater at 60 % (17.5 ± 6.6 °C min) than 75 % (3.4 ± 4.8 °C min; P < 0.001), whereas the rate of increase in rectal temperature was greater at 75 % (5.1 ± 1.7 vs. 2.2 ± 1.4 °C h(-1); P < 0.001). iHsp72 concentration increased similarly at exhaustion relative to pre-exercise (P = 0.044) and then increased further at 24 h (P < 0.001). Multiple regression analysis revealed no predictor variables associated with iHsp72 expression; however, a correlation was observed between exercise intensities for the increase in iHsp expression at exhaustion and 24 h (P < 0.05). These results suggest that iHsp72 expression increased in relation to the level of hyperthermia attained and sustained at 60 % and the higher metabolic rate and greater rate of increase in core temperature at 75 %, with the further increase in iHsp72 concentration 24 h after exercise reinforcing its role as a chaperone and cytoprotective agent.

Activated endothelial cells limit inflammatory response, but increase chemoattractant potential and bacterial clearance by human monocytes

Inflammation is the normal immune response of vascularized tissues to damage and bacterial products, for which leukocyte transendothelial migration (TEM) is critical. The effects of cell-to-cell contact seen in both leukocyte and endothelial cells include cytoskeleton rearrangement, and dynamic expression of adhesion molecules and metalloproteinases. TEM induces expression of anti-apoptotic molecules, costimulatory molecules associated with antigen presentation, and pattern recognition receptors (PRR), such as TLR-4, in monocytes. However, little is known about how TLR-4 increment operates in monocytes during an inflammatory response. To understand it better, we used an in vitro model in which monocytes crossed a layer of IL-1β stimulated Human Umbilical Vein Endothelial Cells (HUVEC). After TEM, monocytes were tested for the secretion of inflammatory cytokines and chemokines, their phenotype (CD14, CD16, TLR-4 expression), and TLR-4 canonical [Nuclear Factor kappa B, (NF-κB) pathway] and non-canonical [p38, extracellular signal-regulated kinases (ERK) 1/2 pathway] signal transduction induced by lipopolysaccharide (LPS). Phagocytosis and bacterial clearance were also measured. There was diminished secretion of LPS-induced inflammatory cytokines (IL-1β, IL-6, and TNF-α) and higher secretion of chemokines (CXCL8/IL-8 and CCL2/MCP-1) in supernatant of TEM monocytes. These changes were accompanied by increases in TLR-4, CD14 (surfaces expression), p38, and ERK1/2 phosphorylated cytoplasmic forms, without affecting NF-κB activation. It also increased bacterial clearance after TEM by an O2 -independent mechanism. The data suggest that interaction between endothelial cells and monocytes fine-tunes the inflammatory response and promotes bacterial elimination.

Defining the genetic relationship of protegrin-related sequences and the in vivo expression of protegrins

Protegrins (PGs) are potent antimicrobial peptides that act on a broad spectrum of microorganisms, including bacteria, fungi and some enveloped viruses. We analyzed the expression pattern of protegrins in 17 different pig tissues using RT-PCR, and developed an anti-(PG-1) polyclonal IgG. Western blot analysis using the antibody showed that protegrins are mainly present as prepropeptide forms in normal tissues, rather than as mature peptides. Immunohistochemical analysis showed that protegrin expression was specific to a few cell types, including neutrophils, pulmonary club, epithelial and Leydig cells. Genetic analyses of the five previously reported protegrin sequences showed that they are encoded at a single locus, rather than from multiple paralogous genes. By genotyping 28 animals across five breeds, we identified eight different alleles of the PGs.

Lipoprotein-associated phospholipase A2 regulates macrophage apoptosis via the Akt and caspase-7 pathways

AIM

Mutations in lipoprotein-associated phospholipase A2 (Lp-PLA2) are related to atherosclerosis. However, the molecular effects of Lp-PLA2 on atherosclerosis have not been fully investigated. Therefore, this study attempted to elucidate this issue.

METHODS

Monocytes were isolated from randomly selected healthy male volunteers according to each Lp-PLA2 genotype (wild-type Lp-PLA2 [Lp-PLA2 (V/V)], the heterozygous V279F mutation [LpPLA2 (V/F)] and the homozygous V279F mutation [Lp-PLA2 (F/F)]) and differentiated into macrophages. The level of apoptosis in the macrophages following incubation without serum was measured using the annexin V/propidium iodide double staining method, and the underlying mechanisms were further examined using a culture cell line.

RESULTS

The average plasma Lp-PLA2 concentration [Lp-PLA2 (V/V): 129.4 ng/mL, Lp-PLA2 (V/F): 70.7 ng/mL, Lp-PLA2 (F/F): 0.4 ng/mL] and activity [Lp-PLA2 (V/V): 164.3 nmol/min/mL, LpPLA2 (V/F): 100.9 nmol/min/mL, Lp-PLA2 (F/F): 11.6 nmol/min/mL] were significantly different between each genotype, although the basic clinical characteristics were similar. The percentage of apoptotic cells was significantly higher among the Lp-PLA2 (F/F) macrophages compared with that observed in the Lp-PLA2 (V/V) macrophages. This induction of apoptosis was independent of the actions of acetylated low-density lipoproteins. In addition, the transfection of the expression plasmid of V279F mutant Lp-PLA2 into Cos-7 cells or monocyte/macrophage-like U937 cells promoted apoptosis. The knockdown of Lp-PLA2 also increased the number of apoptotic cells. Among the cells expressing mutant Lp-PLA2, the caspase-7 activity was increased, while the activated Akt level was decreased.

CONCLUSIONS

The V279F mutation of Lp-PLA2 positively regulates the induction of apoptosis in macrophages and Cos-7 cells. An increase in the caspase-7 activity and a reduction in the activated Akt level are likely to be involved in this phenomenon.

SPION primes THP1 derived M2 macrophages towards M1-like macrophages

Potentially, cellular iron regulates functional plasticity in macrophages yet; interaction of functionally polarized macrophages with iron-oxide nanoparticles has never been studied. We found that monocyte differentiation alters cellular ferritin and cathepsin L levels and induces functional polarization in macrophages. Iron in super paramagnetic iron-oxide nanoparticle (SPION) induces a phenotypic shift in THP1 derived M2 macrophages towards a high CD86+ and high TNF α+ macrophage subtype. This phenotypic shift was accompanied by up-regulated intracellular levels of ferritin and cathepsin L in M2 macrophages, which is a characteristic hallmark of M1 macrophages. Atherogenic oxysterols reduce phagocytic activity in macrophage subtypes, and thus these cells may escape detection by iron-oxide nanoparticles (INPs) in-vivo.

Fortilin reduces apoptosis in macrophages and promotes atherosclerosis

Atherosclerosis, a deadly disease insufficiently addressed by cholesterol-lowering drugs, needs new therapeutic strategies. Fortilin, a 172-amino acid multifunctional polypeptide, binds p53 and blocks its transcriptional activation of Bax, thereby exerting potent antiapoptotic activity. Although fortilin-overexpressing mice reportedly exhibit hypertension and accelerated atherosclerosis, it remains unknown if fortilin, not hypertension, facilitates atherosclerosis. Our objective was to test the hypothesis that fortilin in and of itself facilitates atherosclerosis by protecting macrophages against apoptosis. We generated fortilin-deficient (fortilin(+/-)) mice and wild-type counterparts (fortilin(+/+)) on a LDL receptor (Ldlr)(-/-) apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (Apobec1)(-/-) hypercholesterolemic genetic background, incubated them for 10 mo on a normal chow diet, and assessed the degree and extent of atherosclerosis. Despite similar blood pressure and lipid profiles, fortilin(+/-) mice exhibited significantly less atherosclerosis in their aortae than their fortilin(+/+) littermate controls. Quantitative immunostaining and flow cytometry analyses showed that the atherosclerotic lesions of fortilin(+/-) mice contained fewer macrophages than those of fortilin(+/+) mice. In addition, there were more apoptotic cells in the intima of fortilin(+/-) mice than in the intima of fortilin(+/+) mice. Furthermore, peritoneal macrophages from fortilin(+/-) mice expressed more Bax and underwent increased apoptosis, both at the baseline level and in response to oxidized LDL. Finally, hypercholesterolemic sera from Ldlr(-/-)Apobec1(-/-) mice induced fortilin in peritoneal macrophages more robustly than sera from control mice. In conclusion, fortilin, induced in the proatherosclerotic microenvironment in macrophages, protects macrophages against Bax-induced apoptosis, allows them to propagate, and accelerates atherosclerosis. Anti-fortilin therapy thus may represent a promising next generation antiatherosclerotic therapeutic strategy.

Single-cell analysis and sorting using droplet-based microfluidics

We present a droplet-based microfluidics protocol for high-throughput analysis and sorting of single cells. Compartmentalization of single cells in droplets enables the analysis of proteins released from or secreted by cells, thereby overcoming one of the major limitations of traditional flow cytometry and fluorescence-activated cell sorting. As an example of this approach, we detail a binding assay for detecting antibodies secreted from single mouse hybridoma cells. Secreted antibodies are detected after only 15 min by co-compartmentalizing single mouse hybridoma cells, a fluorescent probe and single beads coated with anti-mouse IgG antibodies in 50-pl droplets. The beads capture the secreted antibodies and, when the captured antibodies bind to the probe, the fluorescence becomes localized on the beads, generating a clearly distinguishable fluorescence signal that enables droplet sorting at ∼200 Hz as well as cell enrichment. The microfluidic system described is easily adapted for screening other intracellular, cell-surface or secreted proteins and for quantifying catalytic or regulatory activities. In order to screen ∼1 million cells, the microfluidic operations require 2-6 h; the entire process, including preparation of microfluidic devices and mammalian cells, requires 5-7 d.

Enhancement of Th1-biased protective immunity against avian influenza H9N2 virus via oral co-administration of attenuated Salmonella enterica serovar Typhimurium expressing chicken interferon-α and interleukin-18 along with an inactivated vaccine

Background

Control of currently circulating re-assorted low-pathogenicity avian influenza (LPAI) H9N2 is a major concern for both animal and human health. Thus, an improved LPAI H9N2 vaccination strategy is needed to induce complete immunity in chickens against LPAI H9N2 virus strains. Cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. To improve the efficacy of inactivated LPAI H9N2 vaccine, attenuated Salmonella enterica serovar Typhimurium was used for oral co-administration of chicken interferon-α (chIFN-α) and chicken interleukin-18 (chIL-18) as natural immunomodulators.

Results

Oral co-administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18, prior to vaccination with inactivated AI H9N2 vaccine, modulated the immune response of chickens against the vaccine antigen through enhanced humoral and Th1-biased cell-mediated immunity, compared to chickens that received single administration of S. enterica serovar Typhimurium expressing either chIFN-α or chIL-18. To further test the protective efficacy of this improved vaccination regimen, immunized chickens were intra-tracheally challenged with a high dose of LPAI H9N2 virus. Combined administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18 showed markedly enhanced protection compared to single administration of the construct, as determined by mortality, clinical severity, and feed and water intake. This enhancement of protective immunity was further confirmed by reduced rectal shedding and replication of AIV H9N2 in different tissues of challenged chickens.

Conclusions

Our results indicate the value of combined administration of chIFN-α and chIL-18 using a Salmonella vaccine strain to generate an effective immunization strategy in chickens against LPAI H9N2.

Density gradient multilayer polymerization for creating complex tissue

An adaptable density gradient multilayer polymerization (DGMP) method facilitates simple fabrication of complex multicompartment scaffolds with structurally continuous interfaces. Solvent density liquid-liquid phase segregation compartmentalizes varied mechanical and chemical cues independently. Bulk photopolymerization produces stratified three-dimensional and two-dimensional matrices. Cells attach to patterned adhesion peptides on biomimetic 2D substrates.

Distinct Humoral and Cellular Immunity Induced by Alternating Prime-boost Vaccination Using Plasmid DNA and Live Viral Vector Vaccines Expressing the E Protein of Dengue Virus Type 2

BACKGROUND

Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2).

METHODS

Following immunization with DNA vaccine (pDE), adenovirus (rAd-E), and/or vaccinia virus (VV-E) expressing E protein, E protein-specific IgG and its isotypes were determined by conventional ELISA. Intracellular CD154 and cytokine staining was used for enumerating CD4+ T cells specific for E protein. E protein-specific CD8+ T cell responses were evaluated by in vivo CTL killing activity and intracellular IFN-γ staining.

RESULTS

Among three constructs, VV-E induced the most potent IgG responses, Th1-type cytokine production by stimulated CD4+ T cells, and the CD8+ T cell response. Furthermore, when the three constructs were used for alternating prime-boost vaccination, the results revealed a different pattern of CD4+ and CD8+ T cell responses. i) Priming with VV-E induced higher E-specific IgG level but it was decreased rapidly. ii) Strong CD8+ T cell responses specific for E protein were induced when VV-E was used for the priming step, and such CD8+ T cell responses were significantly boosted with pDE. iii) Priming with rAd-E induced stronger CD4+ T cell responses which subsequently boosted with pDE to a greater extent than VV-E and rAd-E.

CONCLUSION

These results indicate that priming with live viral vector vaccines could induce different patterns of E protein- specific CD4+ and CD8+ T cell responses which were significantly enhanced by booster vaccination with the DNA vaccine. Therefore, our observation will provide valuable information for the establishment of optimal prime-boost vaccination against DenV.

Oral administration of Salmonella enterica serovar Typhimurium expressing swine interleukin-18 induces Th1-biased protective immunity against inactivated vaccine of pseudorabies virus

Enhancing and/or modulating innate and adaptive immunity by cytokines appears to be greatly useful to provide effective protective immunity against infectious diseases. However, an effective delivery system for mass administration in livestock industry is needed because of limitations such as cost, labor, time, and protein stability. Here the immunomodulatory functions of swine interleukine-18 (swIL-18), known as IFN-γ-inducing factor (IGIF), were evaluated in a vaccination model of pseudorabies virus (PrV) using attenuated Salmonella enterica serovar Typhimurium as the oral delivery system. The oral administration of S. enterica serovar Typhimurium expressing swIL-18 prior to vaccination with inactivated PrV vaccine induced enhanced levels of serum PrV-specific IgG and its IgG2 isotype, compared to administration of S. enterica serovar Typhimurium harboring the empty vector. Furthermore, S. enterica serovar Typhimurium expressing swIL-18 mounted Th1-biased cellular immune responses against PrV antigen, as evaluated by the production of IFN-γ and IL-4 from peripheral blood mononuclear cells of piglets. Subsequently, Th1-biased immunity induced by S. enterica serovar Typhimurium expressing swIL-18 showed rapid response and rendered piglets displayed more alleviated clinical signs following the virulent PrV challenge. Also, this alleviation of clinical signs was further confirmed by the reduction of nasal excretion of PrV after challenge. The present study demonstrates the extended use of immunomodulatory functions of swIL-18 orally delivered by attenuated S. enterica serovar Typhimurium.

Enhanced protection against infection with transmissible gastroenteritis virus in piglets by oral co-administration of live attenuated Salmonella enterica serovar Typhimurium expressing swine interferon-α and interleukin-18

The enhanced effect of cytokine combinations has been assessed empirically, based on their immunobiological mechanisms. However, far less is known of the enhanced protection of practical cytokine combinations against viral infection in the livestock industry, due to cost and production issues associated with mass administration. This study demonstrates the enhanced protection of oral co-administration of swine interferon-α (swIFN-α) and interleukin-18 (swIL-18) against infection with transmissible gastroenteritis virus (TGEV) in piglets using attenuated Salmonella enterica serovar Typhimurium as carrier of cytokine proteins. A single oral co-administration of S. enterica serovar Typhimurium expressing swIFN-α and swIL-18 induced enhanced alleviation of the severity of diarrhea caused by TGEV infection, compared to piglets administered S. enterica serovar Typhimurium expressing swIFN-α or swIL-18 alone. This enhancement was further observed by the reduction of TGEV shedding and replication, and the expression of IFN-stimulated gene products in the intestinal tract. The results suggest that the combined administration of the swIFN-α and swIL-18 cytokines using attenuated S. enterica serovar Typhimurium as an oral carrier provides enhanced protection against intestinal tract infection with TGEV.

The synthetic peptides bovine enteric β-defensin (EBD), bovine neutrophil β-defensin (BNBD) 9 and BNBD 3 are chemotactic for immature bovine dendritic cells

Human and murine immature DCs (iDCs) are highly efficient in antigen capture and processing, while as mature cells they present antigen and are potent initiators of cell-mediated immune responses. Consequently, iDCs are logical targets for vaccine antigens. Originally discovered for their antimicrobial activity, and thought of as strictly part of the innate immune system, studies with defensins such as human β (beta)-defensin 2 (hBD2) and murine β-defensin 2 (mBD2) have shown that they can function as chemo-attractant for iDCs and, in vaccination strategies, can enhance antigen-specific adaptive immune responses. Most studies to date have been conducted in mice. In contrast, little is known about defensins in cattle. To expand our understanding of the role of defensins in modulating immune responses in cattle, DCs were generated from bovine monocytes and the immature state of these bovine DCs was characterized phenotypically and through functional assays. By day 3 (DC3), bovine monocyte-derived DCs stained positively for DC-specific receptors CD1, CD80/86, CD205, DC-Lamp and MMR. When compared to conventional 6-day DC cultures or DCs cultured for 10 days with and without maturation factors, these DC3 were functionally at their most immature stage. Fourteen of the 16 known bovine β-defensins were synthesized and the synthetic peptides were screened for their ability to attract bovine iDCs. Bovine DC3 were consistently attracted to BNBD3, an analog of BNBD3 (aBNBD3), BNBD9 and bovine EBD in vitro and to aBNBD3 in vivo. These results are the first to describe chemotactic ability of synthetic bovine β-defensins for immature bovine monocyte-derived DCs.

Systemic and mucosal immunity induced by attenuated Salmonella enterica serovar Typhimurium expressing ORF7 of porcine reproductive and respiratory syndrome virus

Oral administration of attenuated Salmonella vaccine may provide valuable advantages such as low cost, easy preparation, and safety. Attenuated Salmonella vaccines also serve as carriers of foreign antigens and immunomodulatory cytokines. Presently, an attenuated Salmonella enterica serovar Typhimurium strain was used as a carrier for open reading frame 7 (ORF7) protein of porcine reproductive and respiratory syndrome virus (PRRSV), a swine pathogen of significant global economic importance. Initially, an attenuated S. enterica serovar Typhimurium expressing ORF7 gene derived from PRRSV Korean isolate was constructed. Following oral administration of a single dose of the attenuated Salmonella vaccine expressing PRRSV ORF7, humoral and cell-mediated immune responses specific for ORF7 were induced at both systemic and mucosal sites including spleen, mesenteric lymph node, Peyer's patch, and laminar propria, as evaluated by determining serum ORF7-specific IgG and mucosal IgA responses, as well as Th1- and Th2-type cytokine production from antigen-stimulated T cells. The induced humoral responses were sustained for at least 12weeks post-immunization. In particular, the immunized mice displayed immune responses to both the foreign ORF7 antigen and Salmonella itself. The results indicate the value of attenuated S. enterica serovar Typhimurium as an oral carrier of PRRSV antigenic proteins to induce effective systemic and mucosal immunity.

Nrf2 regulates ferroportin 1-mediated iron efflux and counteracts lipopolysaccharide-induced ferroportin 1 mRNA suppression in macrophages

Iron is an essential element of hemoglobin, and efficient iron recycling from senescent erythrocytes by splenic macrophages is required for erythrocyte hemoglobin synthesis during erythropoiesis. Ferroportin 1 (Fpn1) is the sole iron exporter in mammals, and it also regulates iron reutilization. In this study, we demonstrated genetically that a redox-sensitive transcription factor, Nrf2, regulates Fpn1 mRNA expression in macrophages. Nrf2 activation by several electrophilic compounds commonly resulted in the upregulation of Fpn1 mRNA in bone marrow-derived and peritoneal macrophages obtained from wild-type mice but not from Nrf2 knockout mice. Further, Nrf2 activation enhanced iron release from the J774.1 murine macrophage cell line. Previous studies showed that inflammatory stimuli, such as LPS, downregulates macrophage Fpn1 by transcriptional and hepcidin-mediated post-translational mechanisms leading to iron sequestration by macrophages. We showed that two Nrf2 activators, diethyl maleate and sulforaphane (SFN; a natural Nrf2 activator found in broccoli), restored the LPS-induced suppression of Fpn1 mRNA in human and mouse macrophages, respectively. Furthermore, SFN counteracted the LPS-induced increase of Hepcidin mRNA by an Nrf2-independent mechanism in mouse peritoneal macrophages. These results demonstrate that Nrf2 regulates iron efflux from macrophages through Fpn1 gene transcription and suggest that Nrf2 may control iron metabolism during inflammation.

CX(3)CR1 and vascular adhesion protein-1-dependent recruitment of CD16(+) monocytes across human liver sinusoidal endothelium

The liver contains macrophages and myeloid dendritic cells (mDCs) that are critical for the regulation of hepatic inflammation. Most hepatic macrophages and mDCs are derived from monocytes recruited from the blood through poorly understood interactions with hepatic sinusoidal endothelial cells (HSECs). Human CD16(+) monocytes are thought to contain the precursor populations for tissue macrophages and mDCs. We report that CD16(+) cells localize to areas of active inflammation and fibrosis in chronic inflammatory liver disease and that a unique combination of cell surface receptors promotes the transendothelial migration of CD16(+) monocytes through human HSECs under physiological flow. CX(3)CR1 activation was the dominant pertussis-sensitive mechanism controlling transendothelial migration under flow, and expression of the CX(3)CR1 ligand CX(3)CL1 is increased on hepatic sinusoids in chronic inflammatory liver disease. Exposure of CD16(+) monocytes to immobilized purified CX(3)CL1 triggered beta1-integrin-mediated adhesion to vascular cell adhesion molecule-1 and induced the development of a migratory phenotype. Following transmigration or exposure to soluble CX(3)CL1, CD16(+) monocytes rapidly but transiently lost expression of CX(3)CR1. Adhesion and transmigration across HSECs under flow was also dependent on vascular adhesion protein-1 (VAP-1) on the HSECs.

CONCLUSION

Our data suggest that CD16(+) monocytes are recruited by a combination of adhesive signals involving VAP-1 and CX(3)CR1 mediated integrin-activation. Thus a novel combination of surface molecules, including VAP-1 and CX(3)CL1 promotes the recruitment of CD16(+) monocytes to the liver, allowing them to localize at sites of chronic inflammation and fibrosis.

Live attenuated Salmonella enterica serovar Typhimurium expressing swine interferon-alpha has antiviral activity and alleviates clinical signs induced by infection with transmissible gastroenteritis virus in piglets

Enhancing innate and acquired immunity by cytokines such as IFN-alpha appears to be useful as a first line of defense against viral infection. However, the practical use of cytokines in livestock is not evident due to cost and production issues associated with mass administration. In this study, we tested the efficacy of live attenuated Salmonella enterica serovar Typhimurium designed to secrete swine IFN-alpha (swIFN-alpha) protein for preventing the clinical signs caused by infection with transmissible gastroenteritis virus (TGEV), one of the diarrhea-causing viruses in the swine industry. Attenuated Salmonella vaccine (chi8501) containing swIFN-alpha-encoding pYA3560 vector (chi8501/swIFN-alpha) successfully induced the secretion of swIFN-alpha protein into the culture supernatants, as confirmed by SDS-PAGE and Western blot. The culture supernatants of chi8501/swIFN-alpha had antiviral activity against TGEV with 50% effective dose (ED(50)) of 320 per mg of supernatant protein. In addition, oral administration of chi8501/swIFN-alpha reduced the severity of clinical signs caused by TGEV infection with the effect more apparent at 6-8 days post-infection, and reduced excretion of TGEV in feces. Similarly, the amount of TGEV in intestinal tissues and mesenteric lymph node of chi8501/swIFN-alpha-administered piglets was lower than in piglets that were treated with control bacteria. These results indicate the value of attenuated Salmonella vaccines as delivery systems of cytokines that can be used for mass administration, thereby overcoming cost and production issues.

Relaxation effects of ferucarbotran-labeled mesenchymal stem cells at 1.5T and 3T: discrimination of viable from lysed cells

Human mesenchymal stem cells (hMSCs) were labeled with Ferucarbotran by simple incubation and cultured for up to 14 d. Iron content was determined by spectrometry and the intracellular localization of the contrast agent uptake was studied by electron and confocal microscopy. At various time points after labeling, ranging from 1 to 14 d, samples with viable or lysed labeled hMSCs, as well as nonlabeled controls, underwent MRI. Spin-echo (SE) and gradient-echo (GE) sequences with multiple TRs and TEs were used at 1.5T and 3T on a clinical scanner. Spectrometry showed an initial iron oxide uptake of 7.08 pg per cell. Microscopy studies revealed lysosomal compartmentalization. Contrast agent effects of hMSCs were persistent for up to 14 d after labeling. A marked difference in the T(2) effect of compartmentalized iron oxides compared to free iron oxides was found on T(2)-weighted sequences, but not on T(2)*-weighted sequences. The observed differences may be explained by the loss of compartmentalization of iron oxide particles, the uniformity of distribution, and the subsequent increase in dephasing of protons on SE images. These results show that viable cells with compartmentalized iron oxides may-in principle-be distinguished from lysed cells or released iron oxides.

Accelerated stem cell labeling with ferucarbotran and protamine

OBJECTIVE

To develop and characterize a clinically applicable, fast and efficient method for stem cell labeling with ferucarbotran and protamine for depiction with clinical MRI.

METHODS

The hydrodynamic diameter, zeta potential and relaxivities of ferucarbotran and varying concentrations of protamine were measured. Once the optimized ratio was found, human mesenchymal stem cells (MSCs) were labeled at varying incubation times (1-24 h). Viability was assessed via Trypan blue exclusion testing. 150,000 labeled cells in Ficoll solution were imaged with T1-, T2- and T2*-weighted sequences at 3 T, and relaxation rates were calculated.

RESULTS

Varying the concentrations of protamine allows for easy modification of the physicochemical properties. Simple incubation with ferucarbotran alone resulted in efficient labeling after 24 h of incubation while assisted labeling with protamine resulted in similar results after only 1 h. Cell viability remained unaffected. R2 and R2* relaxation rates were drastically increased. Electron microscopy confirmed intracellular iron oxide uptake in lysosomes. Relaxation times correlated with results from ICP-AES.

CONCLUSION

Our results show internalization of ferucarbotran can be accelerated in MSCs with protamine, an approved heparin antagonist and potentially clinically applicable uptake-enhancing agent.

Monocyte urokinase-type plasminogen activator up-regulation reduces thrombus size in a model of venous thrombosis

Background

Our previous studies showed that the direct injection of an adenovirus construct expressing urokinase-type plasminogen activator (uPA) into experimental venous thrombi significantly reduces thrombus weight. The systemic use of adenovirus vectors is limited by inherent hepatic tropism and inflammatory response. As macrophages are recruited into venous thrombi, it is reasonable to speculate that these cells could be used to target the adenovirus uPA (ad-uPA) gene construct to the thrombus. The aims of this study were to determine whether macrophages transduced with ad-uPA have increased fibrinolytic activity and whether systemic injection of transduced cells could be used to target uPA expression to the thrombus and reduce its size.

Methods

The effect of up-regulating uPA was examined in an immortalized macrophage cell line (MM6) and macrophages differentiated from human blood monocyte-derived macrophages (HBMMs). Cells were infected with ad-uPA or blank control virus (ad-blank). Fibrinolytic mediator expression, cell viability, and cytokine expression were measured by activity assays and enzyme-linked immunosorbent assays. Monocyte migration was measured using a modified Boyden chamber assay. A model of venous thrombosis was developed and characterized in mice with severe combined immunodeficiency (SCID). This model was used to study whether systemically administered macrophages over-expressing uPA reduced thrombus size. Uptake of HBMMs into the thrombus induced in these mice was confirmed by a combination of PKH2-labeled cell tracking and colocalization with human leukocyte antigen (HLA) by immunohistology.

Results

Compared with ad-blank, treated HBMMs transduction with ad-uPA increased uPA production by >1000-fold (P = .003), uPA activity by 150-fold (P = .0001), and soluble uPA receptor (uPAR) by almost twofold (P = .043). Expression of plasminogen activator inhibitor (PAI-1) and PAI-2 was decreased by about twofold (P = .011) and threefold (P = .005), respectively. Up-regulation of uPA had no effect on cell viability or inflammatory cytokine production compared with ad-blank or untreated cells. Ad-uPA transduction increased the migration rate of HBMMs (about 20%, P = .03) and MM6 cells (>twofold, P = .005) compared with ad-blank treated controls. Human macrophage recruitment into the mouse thrombus was confirmed by the colocalization of HLA with the PKH2-marked cells. Systemic injection of uPA-up-regulated HBMMs reduced thrombus weight by approximately 20% compared with ad-blank (P = .038) or sham-treated controls (P = .0028).

Conclusion

Transduction of HBBM with ad-uPA increases their fibrinolytic activity. Systemic administration of uPA up-regulated HBBMs reduced thrombus size in an experimental model of venous thrombosis. Alternative methods of delivering fibrinolytic agents are worth exploring.

The use of thrombolysis in the treatment of acute iliofemoral deep vein thrombosis is not suitable for all patients. Our previous studies have shown that direct injection of an adenovirus construct expressing urokinase plasminogen activator (uPA) into experimental venous thrombi significantly reduced thrombus weight. The systemic use of adenovirus vectors is, however, limited by both their inherent hepatic tropism, which precludes targeted delivery to disease sites, and by the associated host inflammatory response. As macrophages are recruited into venous thrombi, these cells could be used to target uPA gene constructs to the thrombus after systemic administration.

Bioactive silica-collagen composite xerogels modified by calcium phosphate phases with adjustable mechanical properties for bone replacement

The development of composites has been recognized as a promising strategy to fulfil the complex requirements of biomaterials. The present study reports on the modification of a novel silica-collagen composite material by varying the inorganic/organic mass ratio and introducing calcium phosphate cement (CPC) as a third component. The sol-gel technique is used for processing, followed by xerogel formation under specific temperature and relative humidity conditions. Cylindrical monolithic samples up to 400mm(3) were obtained without any sintering processes. Various hierarchical phases of the organic component were applied, ranging from tropocollagen and collagen fibrils up to collagen fibers, each characterized by atomic force microscopy. Focusing on the application of fibrils, various inorganic/organic mass ratios were used: 100/0, 85/15 and 70/30; their influence on the structure of the composite material was demonstrated by scanning electron microscopy. The composition was extended by the addition of 25wt.% CPC which led to increased bioactivity by accelerating the formation of bone apatite layers in simulated body fluid. Synchrotron microcomputed tomography demonstrated the homogeneous distribution of the cement particles in the silica-collagen matrix. Compressive strength tests showed that the mechanical properties of the brittle pure silica gel are changed significantly due to collagen addition. The highest ultimate strength of about 115MPa at about 18% total strain was registered for the 70/30 silica-collagen composite xerogels. Incorporation of CPC lowered the gel's strength. By demonstrating differentiation of human monocytes into osteoclast-like cells, an important feature of the composite material regarding successful bone remodeling is fulfilled.

Activated autologous macrophage implantation in a large-animal model of spinal cord injury

OBJECT

Axonal regeneration may be hindered following spinal cord injury (SCI) by a limited immune response and insufficient macrophage recruitment. This limitation has been partially surmounted in small-mammal models of SCI by implanting activated autologous macrophages (AAMs). The authors sought to replicate these results in a canine model of partial SCI.

METHODS

Six dogs underwent left T-13 spinal cord hemisection. The AAMs were implanted at both ends of the lesion in 4 dogs, and 2 other dogs received sham implantations of cell media. Cortical motor evoked potentials (MEPs) were used to assess electrophysiological recovery. Functional motor recovery was assessed with a modified Tarlov Scale. After 9 months, animals were injected with wheat germ agglutinin-horseradish peroxidase at L-2 and killed for histological assessment.

RESULTS

Three of the 4 dogs that received AAM implants and 1 of the 2 negative control dogs showed clear recovery of MEP response. Behavioral assessment showed no difference in motor function between the AAM-treated and control groups. Histological investigation with an axonal retrograde tracer showed neither local fiber crossing nor significant uptake in the contralateral red nucleus in both implanted and negative control groups.

CONCLUSIONS

In a large-animal model of partial SCI treated with implanted AAMs, the authors saw no morphological or histological evidence of axonal regeneration. Although they observed partial electrophysiological and functional motor recovery in all dogs, this recovery was not enhanced in animals treated with implanted AAMs. Furthermore, there was no morphological or histological evidence of axonal regeneration in animals with implants that accounted for the observed recovery. The explanation for this finding is probably multifactorial, but the authors believe that the AAM implantation does not produce axonal regeneration, and therefore is a technology that requires further investigation before it can be clinically relied on to ameliorate SCI.

Adenovirus-Mediated VEGF Gene Therapy Enhances Venous Thrombus Recanalization and Resolution

Objective— Rapid thrombus recanalization reduces the incidence of post–thrombotic complications. This study aimed to discover whether adenovirus-mediated transfection of the vascular endothelial growth factor gene (ad.VEGF) enhanced thrombus recanalization and resolution.

Methods and Results— In rats, thrombi were directly injected with either ad.VEGF (n=40) or ad.GFP (n=37). Thrombi in SCID mice (n=12) were injected with human macrophages transfected with ad.VEGF or ad.GFP. Thrombi were analyzed at 1 to 14 days. GFP was found mainly in the vein wall and adventitia by 3 days, but was predominantly found in cells within the body of thrombus by day 7. VEGF levels peaked at 4 days (376±299 pg/mg protein). Ad.VEGF treatment reduced thrombus size by >50% (47.7±5.1 mm 2 to 22.0±4.0 mm 2 , P =0.0003) and increased recanalization by >3-fold (3.9±0.69% to 13.6±4.1%, P =0.024) compared with controls. Ad.VEGF treatment increased macrophage recruitment into the thrombus by more than 50% ( P =0.002). Ad.VEGF-transfected macrophages reduced thrombus size by 30% compared with controls (12.3±0.89 mm 2 to 8.7±1.4 mm 2 , P =0.04) and enhanced vein lumen recanalization (3.39±0.34% to 5.07±0.57%, P =0.02).

Conclusion— Treatment with ad.VEGF enhanced thrombus recanalization and resolution, probably as a consequence of an increase in macrophage recruitment.

Evaluation of nonleukoreduced red blood cell transfusion units collected at delivery from the placenta

BACKGROUND

The objective of this study was to evaluate the suitability of cord blood (CB) as a source of red blood cells (RBCs) for autologous transfusion.

STUDY DESIGN AND METHODS

CB was collected in 150-mL storage containers with citrate phosphate dextrose (CPD) as anticoagulant and stored in either saline, adenine, glucose, and mannitol (SAG-M; n = 18) or phosphate, adenine, glucose, guanosine, saline, and mannitol (PAGGS-M; n = 18) for 35 days at 4 degrees C. Hematologic status and hemolysis were studied. The lipopolysaccharide (LPS)-induced production of tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 from CB monocytes was analyzed after incubation with addition of weekly sampled supernatants from the CB RBC units. Five additional units (PAGGS-M) were leukoreduced and thereafter analyzed as indicated above.

RESULTS

Hemolysis increased significantly over time, in SAG-M more than in PAGGS-M. During storage in both media, the number of white blood cells (WBCs) decreased, and the LPS-induced production of TNF-alpha and TGF-beta1 decreased and increased, respectively. There were no significant changes in the LPS-induced production of TNF-alpha and TGF-beta1 in the leukoreduced CB RBC units.

CONCLUSION

Hemolysis in CB RBC units increased significantly over time, and PAGGS-M appears to be superior to SAG-M as a preservation solution for CB RBC. The changes in LPS-induced TNF-alpha and TGF-beta1 production over time were probably caused by substances released from apoptotic and/or necrotic WBCs. Further studies are needed to identify both which substances are responsible for the changes in LPS-induced cytokine release and the clinical significance hereof.

Binding of pleomorphic adenoma gene-like 2 to the tumor necrosis factor (TNF)-alpha-responsive region of the NCF2 promoter regulates p67(phox) expression and NADPH oxidase activity

NCF2, the gene encoding the NADPH oxidase cytosolic component p67(phox), is up-regulated by TNF-alpha, and we recently mapped a region in the NCF2 promoter that was required for this TNF-alpha-dependent response. Because this TNF-alpha-responsive region (TRR) lacked recognizable transcription factor binding elements, we performed studies to identify factors involved in regulating NCF2 via the TRR. Using the TRR sequence as bait in a yeast one-hybrid screen, we identified the zinc finger transcription factor Pleomorphic Adenoma Gene-Like 2 (PLAGL2) as a candidate regulator of NCF2 expression. PLAGL2-specific antibodies were generated that detected the native and SUMO1-modified forms of endogenous PLAGL2. EMSA and DNA-binding protein affinity purification analyses demonstrated specific binding of in vitro-translated as well as endogenously expressed PLAGL2 to the TRR, and chromatin immunoprecipitation assays demonstrated enhanced binding of endogenous PLAGL2 to the TRR in vivo with TNF-alpha treatment. Knockdown of PLAGL2 protein inhibited up-regulation of NCF2 transcript, p67(phox) protein expression, and subsequent superoxide production in response to TNF-alpha. Furthermore, relative levels of native and SUMO1-modified endogenous PLAGL2 protein were modulated in a time-dependant manner in response to TNF-alpha treatment. These data clearly identify PLAGL2 as a novel regulator of NCF2 gene expression as well as NADPH oxidase activity and contribute to a greater understanding of the transcriptional regulation of NCF2.

Analysis of proinflammatory activity of highly purified eukaryotic recombinant HMGB1 (amphoterin)

HMGB1 (amphoterin) is a 30-kDa heparin-binding protein that mediates transendothelial migration of monocytes and has proinflammatory cytokine-like activities. In this study, we have investigated proinflammatory activities of both highly purified eukaryotic HMGB1 and bacterially produced recombinant HMGB1 proteins. Mass analyses revealed that recombinant eukaryotic HMGB1 has an intrachain disulphide bond. In mass analysis of tissue-derived HMGB1, two forms were detected: the carboxyl terminal glutamic acid residue lacking form and a full-length form. Cell culture studies indicated that both eukaryotic and bacterial HMGB1 proteins induce TNF-alpha secretion and nitric oxide release from mononuclear cells. Affinity chromatography analysis revealed that HMGB1 binds tightly to proinflammatory bacterial substances. A soluble proinflammatory substance was separated from the bacterial recombinant HMGB1 by chloroform-methanol treatment. HMGB1 interacted with phosphatidylserine in both solid-phase binding and cell culture assays, suggesting that HMGB1 may regulate phosphatidylserine-dependent immune reactions. In conclusion, HMGB1 polypeptide has a weak proinflammatory activity by itself, and it binds to bacterial substances, including lipids, that may strengthen its effects.

A comparison of ovine monocyte-derived macrophage function following infection with Mycobacterium avium ssp. avium and Mycobacterium avium ssp. paratuberculosis

Mycobacterium avium ssp. paratuberculosis causes Johne's disease in ruminants, whereas the antigenically and genetically similar subspecies Mycobacterium avium ssp. avium is less virulent. In this study, we compared one strain of each subspecies for its ability to survive, induce cytokines, suppress MHC class I and II expression and induce apoptosis or necrosis in ovine monocyte-derived macrophages. Both subspecies survived intracellularly and induced the secretion of IL-10. Low levels of TNF-alpha were detected after infection with both subspecies at 4 h. IL-12 was not upregulated after infection. Downregulation of MHC class I and II was evident in response to infection with both M. avium ssp. avium and M. avium ssp. paratuberculosis. No significant cytotoxicity was detectable in ovine macrophages after the addition of bacteria. M. avium ssp. paratuberculosis induced slightly more apoptosis than M. avium ssp. avium. Still the overall rate of apoptosis was very low and both subspecies suppressed LPS-induced macrophage apoptosis.

Macrophage immunomodulatory activity of polysaccharides isolated from Juniperus scopolorum

Extracts of cones and leaves of different species of the genus Juniperus have been used for centuries to treat a variety of medical problems; however, little is known about the active components conferring therapeutic properties to these extracts. To address this issue, we extracted water-soluble polysaccharides from Juniperus scopolorum cones and used ion exchange and size exclusion chromatography to separate them into five fractions, with estimated Mr of 30, 60, 100, 200, and 680 kDa, respectively. All fractions contained type II arabinogalactan in their structure, as determined by reaction with Yariv reagent and structural analysis by proton nuclear magnetic resonance spectroscopy, but lacked complement fixing activity. Analysis of the effects of Juniper polysaccharides on murine peritoneal macrophages, cultured J774.A1 macrophages, and human mononuclear phagocytes demonstrated that the high molecular weight polysaccharide fractions (200 and 680 kDa) had potent immunomodulatory activity. These polysaccharide fractions primed macrophages for an enhanced respiratory burst, directly stimulated NO production via induction of nitric oxide synthase, and induced macrophages to secrete both inflammatory (IL-1, IL-6, TNF-alpha, and IL-12) and anti-inflammatory (IL-10) cytokines. These data suggest that at least part of the beneficial therapeutic effects reported for extracts of juniper cones are due to modulation of monocyte/macrophage immune functions.

Variants of the 5'-untranslated region of human NCF2: expression and translational efficiency

The NCF2 gene encodes p67(phox), an essential component of the multi-protein NADPH oxidase enzyme in phagocytic leukocytes, as well as in certain non-phagocytic cells. In humans, the NCF2 gene is expressed as multiple NCF2 variants that differ in the 5'-untranslated region (5'-UTR). Previously, we reported the presence of four NCF2 5'-UTR mRNA variants (designated as NCF2 exon 1, intron 1a, intron 1b and intron 1c). As each of the gene variants encodes an identical p67(phox) protein, the functional significance of these message variants was not apparent. In this study, we investigated the relative expression levels and tissue-specificity of NCF2 5'-UTR variant mRNAs and their translation efficiency and stability. NCF2 5'-UTR variant transcripts were differentially expressed in various cell lines and human tissues. In vitro translation assays indicated that the NCF2 5'-UTR variants also differed in their effects on the translation of a luciferase reporter mRNA and NCF2 mRNA. Notably, NCF2 intron 1 5'-UTR variants, which are the predominantly expressed variants found in vivo, strongly inhibited translation when compared to the NCF2 exon 1 5'-UTR variant. In contrast, RNA decay assays demonstrated that there was no significant difference between stability of NCF2 intron 1 transcripts and the exon 1 5'-UTR variant in HL-60, MonoMac 6, and U937 cells. Moreover, expression of the variant transcripts remained unchanged after neutrophil phagocytosis, and was similar in normal neutrophils and neutrophils from a patient with X-linked chronic granulomatous disease. These studies suggest that expression of p67(phox) is regulated through mechanisms that include modulation of transcription and translation.

T1 and T2 relaxivity of intracellular and extracellular USPIO at 1.5T and 3T clinical MR scanning

In this study we evaluated the effects of intracellular compartmentalization of the ultrasmall superparamagnetic iron oxide (USPIO) ferumoxtran-10 on its proton T1 and T2 relaxivities at 1.5 and 3T. Monocytes were labeled with ferumoxtran-10 by simple incubation. Decreasing quantities of ferumoxtran-10-labeled cells (2.5x10(7)-0.3x10(7) cells/ml) and decreasing concentrations of free ferumoxtran-10 (without cells) in Ficoll solution were evaluated with 1.5 and 3T clinical magnetic resonance (MR) scanners. Pulse sequences comprised axial spin echo (SE) sequences with multiple TRs and fixed TE and SE sequences with fixed TR and increasing TEs. Signal intensity measurements were used to calculate T1 and T2 relaxation times of all samples, assuming a monoexponential signal decay. The iron content in all samples was determined by inductively coupled plasma atomic emission spectrometry and used for calculating relaxivities. Measurements at 1.5T and 3T showed higher T1 and T2 relaxivity values of free extracellular ferumoxtran-10 as opposed to intracellularly compartmentalized ferumoxtran-10, under the evaluated conditions of homogeneously dispersed contrast agents/cells in Ficoll solution and a cell density of up to 2.5x10(7) cells/ml. At 3T, differences in T1-relaxivities between intra- and extracellular USPIO were smaller, while differences in USPIO T2-relaxivities were similar compared with 1.5T. In conclusion, cellular compartmentalization of ferumoxtran-10 changes proton relaxivity.

p21-activated kinase (Pak) regulates NADPH oxidase activation in human neutrophils

The phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase plays an instrumental role in host defense and contributes to microbicial killing by releasing highly reactive oxygen species. This multicomponent enzyme is composed of membrane and cytosolic components that assemble in the plasma membrane or phagolysosome. While the guanosine S'-triphosphatase (GTPase) Rac2 has been shown to be a critical regulator of NADPH oxidase activity and assembly, the role of its effector, p21-activated kinase (Pak), in oxidase function has not been well defined. Using HIV-1 Tat-mediated protein transduction of Pak inhibitory domain, we show here that Pak activity is indeed required for efficient superoxide generation in intact neutrophils. Furthermore, we show that Pak translocates to the plasma membrane upon N-formyl-methionyl-leucyl-phenylalanine (fMLF) stimulation and colocalizes with translocated p47(phox) and with p22phox, a subunit of flavocytochrome b558. Although activated Pak phosphorylated several essential serine residues in the C-terminus of p47phox, direct binding to p47phox was not observed. In contrast, active Pak bound directly to p22phox, suggesting flavocytochrome b was the oxidase-associated membrane target of this kinase and this association may facilitate further phosphorylation of p47phox in the assembling NADPH oxidase complex.

Increased monocyte transcription of the proteinase 3 gene in small vessel vasculitis

Proteinase 3 (PR3) is a pleiotropic and destructive serine protease and it is also a major target for autoantibodies in systemic small vessel vasculitis. We have shown recently that patients in stable remission have increased circulating levels of PR3, independent of autoantibody titre, inflammation, neutrophil degranulation and renal function. Here we explore the possibility of increased PR3 gene transcription. RNA was purified from peripheral blood monocytes from vasculitis patients and controls. Specific mRNA was measured by TaqMan real-time polymerase chain reaction (PCR). The monocyte-like cell lines THP-1 and U937 and human peripheral blod monocytes from healthy controls were stimulated with cytokines and lipopolysaccharide (LPS) for different time periods. PR3 protein was measured in plasma with enzyme-linked immunosorbent assay (ELISA). The median result for PR3 mRNA was 9.6 (1.8-680) for 22 patients, compared to 1 (0.1-2.8) for the 15 healthy controls. Elastase expression was also significantly increased, whereas myeloperoxidase and interleukin-8 were not. Stimulation of monocytes with tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma or LPS did not result in any increase of PR3 or elastase transcription, whereas interleukin (IL)-8 transcription was increased 10-fold. Circulating monocytes from patients with systemic vasculitis display increased PR3 gene transcription compared to healthy controls and patients with sytemic lupus erythematosus (SLE). This may be important for the development of vasculitis. Our results do not favour a role for cytokines, antineutrophil cytoplasmic antibodies (ANCA) or immunosuppressive medication in the upregulation of PR3 transcription in vasculitis.

The recognition of adsorbed and denatured proteins of different topographies by β2 integrins and effects on leukocyte adhesion and activation

Leukocyte beta2 integrins Mac-1 and p150,95 are promiscuous cell-surface receptors that recognise and mediate cell adhesion to a variety of adsorbed and denatured proteins. We used albumin as a model protein to study whether leukocyte adhesion and activation depended on the nm-scale topography of a protein adlayer. Albumin adsorbed from the native conformation gave rise to different adlayer topographies and different amounts of adsorbed protein on hydrophobic and relatively hydrophilic polystyrene and silanised silicon-wafer surfaces, whereas adsorption of pre-denatured Alb resulted in similar adlayer topographies and similar amounts of adsorbed protein on these surfaces. All three distinct protein-adlayer topographies supported adhesion of in vitro differentiated, macrophage-like U937 and THP-1 cells, but did not support adhesion of their promonocytic precursors. Human monocytes freshly isolated from peripheral blood did not adhere to adsorbed albumin, not even in the presence of monocyte chemoattractant protein-1 and macrophage inflammatory protein-1alpha chemokines. Adhesion of the macrophage-like cells to albumin in any of the three topographies was inhibited by antibodies against beta2 integrins, but not by antibodies against beta1 integrins, and did not induce secretion of the proinflammatory cytokine tumour necrosis factor-alpha.

Effect of P-Selectin on Phosphatidylserine Exposure and Surface-Dependent Thrombin Generation on Monocytes

OBJECTIVE

Stimulation of monocytes with P-selectin induces the synthesis of an array of mediators of inflammation, as well as the expression of tissue factor (TF), the main initiator of coagulation. Because the membrane-bound reactions of coagulation are profoundly influenced by the presence of phosphatidylserine on the membranes of cells, factors that increase its expression may have an impact on coagulation.

METHODS AND RESULTS

Using flow cytometry, we studied the effect of P-selectin on phosphatidylserine expression in blood monocytes and in the monocytic cells, THP-1. Soluble P-selectin at biologically relevant concentrations (0.31 to 2.5 microg/mL) induced a time-dependent increase in phosphatidylserine expression, an effect that could be inhibited with an anti-PSGL-1 blocking antibody, and by genistein, a tyrosine kinase inhibitor. Binding of activated platelets to THP-1 cells also resulted in a significant increase in phosphatidylserine expression that was dependent on PSGL-1. Consistent with the role of phosphatidylserine on surface-dependent reactions of coagulation, treatment of monocytic cells with soluble P-selectin led to increased thrombin generation. We excluded P-selectin induced apoptosis of monocyte as a mechanism for the increased phosphatidylserine exposure.

CONCLUSIONS

In summary, we show that P-selectin, either soluble or in its membrane-bound form, induces phosphatidylserine exposure in monocytes through a mechanism dependent on PSGL-1.

Circulating cytokine profile in anti-neutrophilic cytoplasmatic autoantibody-associated vasculitis: prediction of outcome?

AIMS: The anti-neutrophilic cytoplasmatic autoantibody-associated vasculitides (AASV) are diseases of relapsing-remitting inflammation. Here we explore the cytokine profile in different phases of disease, looking for pathogenic clues of possible prognostic value. RESULTS: Interleukin (IL)-6, IL-8 and IL-10 were significantly elevated in plasma. Patients in the stable phase who subsequently developed adverse events had higher IL-8 values. Patients in the stable phase who relapsed within 3 months had lower IL-10 values and higher IL-6 levels. CONCLUSIONS: Patients with AASV have raised circulating cytokine levels compared with healthy controls, even during remission. Raised IL-8 seems associated with poor prognosis. Lower levels of IL-10 and higher levels of IL-6 herald a greater risk of relapse. Patients with systemic vasculitis in clinical remission have persistent disease activity, kept under control by inhibitory cytokines.