Human Macrophage-like THP-1 Cells Research Articles

Fumonisin production and toxic capacity in airborne black Aspergilli

This study presents the distribution of fumonisin (FB)-producing and non-producing airborne Aspergilli (Nigri) in apartments (AP), basements (BS) and a grain mill (GM) in Croatia, and their cytotoxic, immunomodulation and genotoxic potency in comparison with FB1 and FB2. Concentration of black Aspergilli was 260-fold higher in GM than in living environment with domination of A. tubingensis and A. welwitschiae. FB2- but not FB1- was confirmed via HPLC-MS and detection of fum1 and fum8 genes for one isolate of A. niger (0.015 μg/mL) and 8/15 isolates of A. welwitschiae (0.128–13.467 μg/mL). After 24 h, both FB1 and FB2 were weakly cytotoxic (MTT assay) to human lung A549 cells and THP-1 macrophage-like cells. In THP-1 cells FB1 but not FB2 provoked a higher increase of IL-8, TNF-α and IL-1β (ELISA). In A549 cells DNA damaging effect of FB1 was slightly higher than that of FB2 (Comet assay). In THP-1 macrophage-like cells A. tubingensis and A. piperis evoked immunomodulatory effects which corresponded to their cytotoxicity (IC50 = 0.228–0.323 mg/mL); A. welwitschiae, A. tubingensis and A. piperis exerted cytotoxic (IC50 = 0.214–0.460 mg/mL) and genotoxic effects in A549 cells. Presumably, secondary metabolites other than FB2 may have contributed to the toxicity of black Aspergilli.

Candida tropicalis induces pro-inflammatory cytokine production, NF-κB and MAPKs pathways regulation, and dectin-1 activation

The prevalence of Candida infection induced by non-albicans Candida (NAC) species is increasing. However, as a common NAC species, C. tropicalis has received much less study in terms of host immunity than C. albicans has. In this study, we evaluated the pro-inflammatory cytokine responses evoked by C. tropicalis and determined whether dectin-1 and downstream NF-κB and mitogen-activated protein kinases (MAPKs) signaling pathways played roles in inflammation in human peripheral blood mononuclear cells (PBMCs) and THP-1 macrophage-like cells. Exposure of PBMCs and THP-1 macrophage-like cells to C. tropicalis led to the enhanced gene expression and secretion of TNF-α and IL-6 in a time- and dose-dependent manner. THP-1 macrophage-like cells being challenged by C. tropicalis resulted in the activation of the NF-κB, p38, and ERK1/2 MAPK signaling pathways. We also found that the expression of dectin-1 was increased with C. tropicalis treatment. These data reveal that dectin-1 may play a role in sensing the inflammation response induced by C. tropicalis and that NF-κB and MAPK are involved in the downstream signaling pathways in macrophages.

α- and β-d-Glucans from the edible mushroom Pleurotus albidus differentially regulate lipid-induced inflammation and foam cell formation in human macrophage-like THP-1 cells

Macrophages play an essential role in lipid metabolism; however, the excessive uptake of modified lipids and cholesterol crystals (CC) leads to the formation of pro-inflammatory lipid-laden macrophages called foam cells. Since the α-1,6- and β-1,3-d-glucans from the basidiome and the mycelium of the edible mushroom Pleurotus albidus have previously been shown to regulate macrophage function, these glucans were tested in macrophage-like THP-1 cells previously exposed to acetylated low-density lipoproteins (acLDL) or CC. The glucans inhibited lipid-induced inflammation, but only the β-1,3-d-glucan regulated both the NLRP3 inflammasome activation and the expression of genes involved on lipid efflux in acLDL- or CC-pretreated cells, thereby reducing foam cell formation. In contrast, the two α-1,6-glucans tested inhibited foam cell formation only in acLDL-pretreated cells and had no effect on the expression of the peroxisome proliferator-activated receptor gamma and liver X receptor alpha genes, suggesting that these glucans regulate lipid influx rather than lipid efflux. Thus, α- and β-d-glucans differentially regulate lipid-induced inflammation and foam cell formation in macrophage-like cells. Furthermore, results emphasize that P. albidus has potential to be used as a functional food or as a source for the extraction of biologically-active glucans.

Effects of the yeast form of Sporothrix schenckii on activation of p38MAPK and expression of interleukin-6 in human THP-1 macrophage-like cells

Objective To evaluate effects of the yeast form of Sporothrix schenckii on activation of p38 mitogen-activated protein kinase (p38MAPK) and expression of interleukin-6 (IL-6) in macrophage-like THP-1 cells, which were differentiated from the human acute monocytic leukemia cell line THP-1. Methods THP-1 macrophage-like cells were divided into 3 groups to be treated with the yeast form of Sporothrix schenckii at a concentration of 2 × 106 colony-forming units (CFU) /ml (yeast form group) , 100 mg/L curdlan (curdlan group) and RPMI 1640 medium (blank control group) respectively. Real-time fluorescence-based quantitative PCR was performed to measure the mRNA expression of IL-6 in THP-1 macrophage-like cells in the above 3 groups after 3-and 6-hour treatment separately, and enzyme-linked immunosorbent assay (ELISA) to detect the level of IL-6 in the culture supernatant of THP-1 macrophage-like cells after 24-hour treatment. Western blot analysis was conducted to determine the protein expression of p38MAPK and phosphorylated p38MAPK (p-p38MAPK) in the above 3 groups after 30-and 60-minute treatment separately. Other THP-1 macrophage-like cells were pretreated with 100 nmol/L dexamethasone (a p38MAPK inhibitor) for 30 minutes, and then were divided into 3 groups to be treated with the yeast form of Sporothrix schenckii, curdlan and RPMI 1640 medium respectively, and changes in the level of p-p38MAPK and mRNA expression of IL-6 were also detected. Statistical analysis was carried out with SPSS19.0 software by using one-way or multi-way analysis of variance and least significant difference (LSD) test. Results Significant differences in the mRNA expression of IL-6 in THP-1 macrophage-like cells were observed among the yeast form group, curdlan group and blank control group (F= 5 552.22, P < 0.001) after 3-hour treatment (56.81 ± 7.36, 26.69 ± 1.22 and 0.97 ± 0.05, respectively) and 6-hour treatment (378.03 ± 16.67, 276.24 ± 39.13 and 1.02 ± 0.04, respectively) . Additionally, the yeast form group showed significantly higher mRNA expression of IL-6 after 6-hour treatment than that after 3-hour treatment (q= 16.74, P < 0.001) . After 24-hour treatment, the level of IL-6 in the culture supernatant of THP-1 macrophage-like cells also significantly differed among the yeast form group, curdlan group and blank control group (59.96 ± 18.16 pg/L, 91.01 ± 17.27 pg/L, 5.50 ± 2.30 pg/L, respectively; F= 26.62, P < 0.01) , and was significantly higher in the yeast form group than in the blank control group (P < 0.01) . After 30-and 60-minute treatment, the protein expression of p-p38MAPK was significantly higher in the yeast form group than in the blank control group (both P < 0.01) . Moreover, the mRNA expression of IL-6 (4.46 ± 1.03 vs. 493.52 ± 113.87, P < 0.001) and protein expression of p-p38MAPK (2.29 ± 0.37 vs. 4.55 ± 0.46, q= 10.81, P < 0.01) were both significantly lower in the yeast form group with dexamethasone pretreatment than in that without dexamethasone pretreatment. Conclusion In vitro treatment with the yeast form of Sporothrix schenckii can enhance the expression of IL-6 in human THP-1 macrophage-like cells by activating the p38MAPK signaling pathway. Key words: Sporothrix; Macrophages; Interleukin-6; p38 Mitogen-activated protein kinases

Airborne Nanoparticle Release and Toxicological Risk from Metal-Oxide-Coated Textiles: Toward a Multiscale Safe-by-Design Approach

Nano metal oxides have been proposed as alternatives to silver (Ag) nanoparticles (NPs) for antibacterial coatings. Here, cotton and polyester-cotton fabrics were sonochemically coated with zinc oxide (ZnO) and copper oxide (CuO) NPs. By varying the reaction solvent (water or ethanol), NPs with different sizes and shapes were synthesized. The cytotoxic and pro-inflammatory effects of studied NPs were investigated in vitro in human alveolar epithelial A549 and macrophage-like THP1 cells. To understand the potential respiratory impact of the NPs, the coated textiles were subjected to the abrasion tests, and the released airborne particles were measured. A very small amount of the studied metal oxides NPs was released from abrasion of the textiles coated by the ethanol-based sonochemical process. The release from the water-based coating was comparably higher. Lung and immune cells viability decreased after 24 h of exposure only at the highest studied NPs concentration (100 μg/mL). Different from the ZnO NPs, both formulations of CuO NPs induced IL-8 release in the lung epithelial cells already at subtoxic concentrations (1-10 μg/mL) but not in immune cells. All of the studied NPs did not induce IL-6 release by the lung and immune cells. Calculations revealed that the exposures of the NPs to human lung due to the abrasion of the textiles were lower or comparable to the minimum doses in the cell viability tests (0.1 μg/mL), at which acute cytotoxicity was not observed. The results alleviate the concerns regarding the potential risk of these metal oxide NPs in their applications for the textile coating and provide insight for the safe-by-design approach.

Role of the LuxR family transcriptional regulator Lpg2524 in the survival of Legionella pneumophila in water.

The water-borne Gram-negative bacterium Legionella pneumophila (Lp) is the causative agent of Legionnaires' disease. Lp is typically transmitted to humans from water systems, where it grows inside amoebae. Survival of Lp in water is central to its transmission to humans. A transcriptomic study previously identified many genes induced by Lp in water. One such gene, lpg2524, encodes a putative LuxR family transcriptional regulator. It was hypothesized that this gene could be involved in the survival of Lp in water. Deletion of lpg2524 does not affect the growth of Lp in rich medium, in the amoeba Acanthamoeba castellanii, or in human macrophage-like THP-1 cells, showing that Lpg2524 is not required for growth in vitro and in vivo. Nevertheless, deletion of lpg2524 results in a faster colony-forming unit (CFU) reduction in an artificial freshwater medium, Fraquil, indicating that Lpg2524 is important for Lp to survive in water. Overexpression of Lpg2524 also results in a survival defect, suggesting that a precise level of this transcriptional regulator is essential for its function. However, our result shows that Lpg2524 is dispensable for survival in water when Lp is at a high cell density (109 CFU/mL), suggesting that its regulon is regulated by another regulator activated at high cell density.

In vitro assessment of plutonium uptake and release using the human macrophage-like THP-1 cells

Plutonium (Pu) intake by inhalation is one of the major potential consequences following an accident in the nuclear industry or after improvised nuclear device explosion. Macrophages are essential players in retention and clearance of inhaled compounds. However, the extent to which these phagocytic cells are involved in these processes highly depends on the solubility properties of the Pu deposited in the lungs. Our objectives were to develop an in vitro model representative of the human pulmonary macrophage capacity to internalize and release Pu compounds in presence or not of the chelating drug diethylenetriaminepentaacetate (DTPA).The monocyte cell line THP-1 was used after differentiation into macrophage-like cells. We assessed the cellular uptake of various forms of Pu which differ in their solubility, as well as the release of the internalized Pu. Results obtained with differentiated THP-1 cells are in good agreement with data from rat alveolar macrophages and fit well with in vivo data. In both cell types, Pu uptake and release depend upon Pu solubility and in all cases DTPA increases Pu release.The proposed model may provide a good complement to in vivo animal experiments and could be used in a first assessment to predict the fraction of Pu that could be potentially trapped, as well as the fraction available to chelating drugs.

A Single Dose of the Anti-Resorptive Peptide Human Calcitonin Paradoxically Augments Particle- and Endotoxin-Mediated Pro-Inflammatory Cytokine Production In Vitro.

The peptide hormone calcitonin (CT) is known to inhibit bone resorption and has previously been shown also to prevent particle-induced osteolysis, the leading cause of revision arthroplasty. In the present study, the influence of human CT on the initial inflammatory response to particulate wear debris or bacterial endotoxins, ultimately leading to osteoclast-mediated bone resorption, was analysed in human THP-1 macrophage-like cells. The cells were activated with either ultra-high molecular weight polyethylene (UHMWPE) particles or bacterial lipopolysaccharides (LPS) in order to simulate an osteolysis-associated inflammatory response. The cells were simultaneously treated with human CT (10(-9) M). Cytokine production of tumour necrosis factor (TNF)-α was quantified on both RNA and protein levels while interleukins (IL)-1β and IL-6 were measured as secreted protein only. Stimulation of the cells with either particles or LPS led to a dose- and time-dependent increase of TNF-α mRNA production and protein secretion of TNF-α, IL-1β, and IL-6. Application of CT mostly enhanced cytokine production as elicited by UHMWPE particles while a pronounced transient inhibitory effect on LPS-induced inflammation became evident at 24 h of incubation. Human CT displayed ambivalent effects on the wear- and LPS-induced production of pro-inflammatory cytokines. Thereby, the peptide primarily upregulated particle-induced inflammation while LPS-induced cytokine secretion was temporarily attenuated in a distinct manner. It needs to be evaluated whether the pro- or anti-inflammatory action of CT contributes to its known anti-resorptive effects. Thus, the therapeutic potential of the peptide in the treatment of either particle- or endotoxin-mediated bone resorption could be determined.

Species diversity and cytotoxic potency of airborne sterigmatocystin-producing Aspergilli from the section Versicolores

This study presents the distribution and species diversity of sterigmatocystin-producing Aspergilli from the section Versicolores in the indoor air of apartment-AP, basements-BS and grain mill-GM in Croatia, as well as the cytotoxic potency of isolates. The species comprised 0.7–20% of total airborne fungi detected in the AP, 11–55% in the BS, and 0–2% in the GM. Based on CaM sequences, seven species were identified; dominant were Aspergillus jensenii and Aspergillus creber, followed by Aspergillus protuberus, Aspergillus venenatus, Aspergillus tennesseensis, Aspergillus amoenus, Aspergillus griseoaurantiacus and three undescribed species. All of the identified species produced sterigmatocystin-STC (HPLC/UV-VIS); A. griseoaurantiacus (208.29μg/mL) and A. jensenii (1.192–133.63μg/mL) produced the highest levels, the lowest were detected in A. protuberus and A. tennesseensis (0.117–2.749μg/mL). Lower species diversity was obtained in the GM due to overgrowth with more propulsive fungi. Relatively high STC levels (0.06–2.35μg/g) detected in 52% of GM dust samples confirmed the presence of STC-producers, although this STC cannot be exclusively attributed to Aspergilli (Versicolores). STC and the majority of STC-producing Aspergilli were cytotoxic to human lung A549 cells (IC50 0.9–2.3μg/mL) and THP-1 macrophage-like cells (IC50 0.3–0.6μg/mL) in relatively low concentrations suggesting that humans can be at high risk during chronic exposure.

Digested protein isolate from fresh and stored Carioca beans reduced markers of atherosclerosis in oxidized LDL-induced THP-1 macrophages

Oxidized LDL (ox-LDL) and its interaction with lectin type ox-LDL receptor (LOX-1) determine atherosclerosis progression. The potential of peptides from digested protein isolate (DPI) derived from fresh and stored Carioca bean (Phaseolus vulgaris L.) to prevent ox-LDL induced inflammation in human THP-1 macrophage-like cells was examined here. BRS Pontal (PO) and BRSMG Madreperola (MP) fresh and stored for 6 months were cooked, and protein isolates were digested by pepsin–pancreatin. Peptides from stored Carioca beans decreased prostaglandin E-2 (PGE-2) (from 17.7 to 47%) and tumour necrosis factor-α (TNF-α) (12.3 to 82%). Stored MP (0.01 mg/mL) inhibited reactive oxygen species (ROS). LOX-1 and matrix metalloproteinase-9 (MMP-9) expression were reduced by peptides from all beans. Stored PO and MP digested protein isolates reduced expression of 10 cytokines related to atherosclerosis process. Peptides from Carioca beans presented anti-atherosclerotic properties comparable to simvastatin, which were related to inhibition of LOX-1, MMP-9 and ICAM-1.

Postharvest storage of Carioca bean (Phaseolus vulgaris L.) did not impair inhibition of inflammation in lipopolysaccharide-induced human THP-1 macrophage-like cells

Storage can affect the nutritional quality of common bean (Phaseolus vulgaris), but little is known about the postharvest effect of storage on inflammation. The aim of this work was to evaluate, in vitro, the effect of postharvest storage-time on inflammation by Carioca beans, Madreperola (MP) and Pontal (PO), stored (0, 3 and 6 months), cooked and subjected to pepsin-pancreatin simulated gastrointestinal digestion. Anti-inflammatory potential was investigated in human THP-1 macrophage-like cells. Commercial storage time did not affect protein concentration, degree of hydrolysis, hydropathicity or antioxidant capacity. All PO hydrolysates reduced tumour necrosis factor-α (TNF- α) (31% on average). MP hydrolysates decreased interleukin 1β (IL-1β) (PO 0: 0.1 mg/mL, 20.7%; PO 0 and 6: 5 mg/mL, 24.8 and 48.2%, respectively) and prostaglandin E-2 (PGE-2) (PO 0: all concentrations, 18% on average; PO 6: 0.1 mg/mL, 18.6%). Carioca beans inhibited inflammation and commercial storage time did not impair physicochemical or biological properties.

Proteome analysis of Bordetella pertussis isolated from human macrophages

Previous studies have shown that B. pertussis survives inside human macrophages in non-acidic compartments with characteristics of early endosomes. In order to gain new insight into the biology of B. pertussis survival in host cells, we have analyzed the adaptation of the bacterial proteome during intracellular infection. The proteome of B. pertussis 3h and 48h after infection of human macrophage-like THP-1 cells was examined by nano-liquid chromatography combined with tandem MS and compared to the protein profile of extracellular B. pertussis growing in the same cell culture medium. Compared with extracellular bacteria, almost 300 proteins out of 762 identified proteins displayed altered levels in intracellular B. pertussis. Functional analyses of the proteins displaying altered abundance revealed enrichment of proteins involved in stress response, iron uptake, cellular metabolism, transcriptional regulation, and virulence.To our knowledge, this is the first analysis of the B. pertussis proteome during adaptation to the intramacrophage environment and the data provide new clues for understanding B. pertussis adaptation and pathogenesis. Biological significanceB. pertussis is a respiratory pathogen that has adapted exclusively to the human host. Despite high vaccination rates, whooping cough remains a serious threat to human health and its incidence has been increasing in recent years in vaccinated populations. The mechanisms that allow this pathogen to evade immune clearance, persist in the host, and cause a prolonged paroxysmal cough are still poorly understood. Recent studies regarding B. pertussis survival inside host cells and the cellular response to this bacterial infection indicate that B. pertussis may have an intracellular phase during infection which probably contributes to persistence and vaccine failure. In this study we provide the first global proteome profile of B. pertussis within macrophages. The data provide novel insights into the adaptive responses elicited by these bacteria for physiological adaptation to the host environment.

The Effects of Shiga Toxin 1, 2 and Their Subunits on Cytokine and Chemokine Expression by Human Macrophage-Like THP-1 Cells.

Infection by Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli (EHEC) results in severe diarrhea, hemorrhagic colitis, and, occasionally, hemolytic-uremic syndrome (HUS). HUS is associated with an increase in pro-inflammatory cytokines and chemokines, many of which are produced by macrophages in the kidneys, indicating that localized host innate immunity likely plays a role in renal pathogenesis. EHEC serotypes may express one or two classes of serologically defined but structurally and functionally-related Shiga toxins called Stx1 and Stx2. Of these, Stx2 appears to be linked to higher rates of HUS than Stx1. To investigate a possible reason for this, we exposed human macrophage-like THP-1 cells to Stx1 or Stx2 and then used the Luminex multiplex system to assess cytokine/chemokine concentrations in culture supernatant solutions. This analysis revealed that, relative to Stx1, Stx2 significantly caused increased expression of GRO, G-CSF, IL-1β, IL-8 and TNFα in macrophage-like THP-1 cells. This was determined to not be due to a difference in cytotoxicity since both Stx1 and Stx2 displayed similar cytotoxic activities on macrophage-like THP-1 cells. These observations indicate that, in vitro, Stx2 can provoke a greater pro-inflammatory response than Stx1 in macrophages and provides a possible partial explanation for higher rates of HUS in patients infected with EHEC strains expressing Stx2. To begin to determine a mechanism for Shiga toxin-mediated cytokine production, we exposed macrophage-like THP-1 cells to Stx1 or Stx2 A and B subunits. Luminex analysis of cytokines in cell culture supernatant solutions demonstrated that neither subunit alone induced a cytokine response in THP-1 cells.

Outer Surface Protein OspC Is an Antiphagocytic Factor That Protects Borrelia burgdorferi from Phagocytosis by Macrophages

Outer surface protein C (OspC) is one of the major lipoproteins expressed on the surface of Borrelia burgdorferi during tick feeding and the early phase of mammalian infection. OspC is required for B. burgdorferi to establish infection in both immunocompetent and SCID mice and has been proposed to facilitate evasion of innate immune defenses. However, the exact biological function of OspC remains elusive. In this study, we showed that the ospC-deficient spirochete could not establish infection in NOD-scid IL2rγ(null) mice that lack B cells, T cells, NK cells, and lytic complement. The ospC mutant also could not establish infection in anti-Ly6G-treated SCID and C3H/HeN mice (depletion of neutrophils). However, depletion of mononuclear phagocytes at the skin site of inoculation in SCID and C3H/HeN mice allowed the ospC mutant to establish infection in vivo. In phagocyte-depleted mice, the ospC mutant was able to colonize the joints and triggered neutrophilia during dissemination. Furthermore, we found that phagocytosis of green fluorescent protein (GFP)-expressing ospC mutant spirochetes by murine peritoneal macrophages and human THP-1 macrophage-like cells, but not in PMN-HL60, was significantly higher than parental wild-type B. burgdorferi strains, suggesting that OspC has an antiphagocytic property. In addition, overproduction of OspC in spirochetes also decreased the uptake of spirochetes by murine peritoneal macrophages. Together, our findings provide evidence that mononuclear phagocytes play a key role in clearance of the ospC mutant and that OspC promotes spirochetes' evasion of macrophages during early Lyme borreliosis.

Effect of cortisol and/or DHEA on THP1-derived macrophages infected with Mycobacterium tuberculosis

Tuberculosis (TB) is a major health problem requiring an appropriate cell immune response to be controlled. Macrophages play a central role in the response against Mycobacterium tuberculosis (Mtb). Given our prior studies in which adrenal steroids were found to modify the cellular immune responses from TB patients, it was sensible to analyze the immunomodulatory capability of cortisol and DHEA on macrophages infected with Mtb. The human macrophage-like THP-1 cells were infected with the H37Rv strain of Mtb and treated with Cortisol and DHEA at different doses. We monitored phagocytosis, intracellular-bacterial growth, autophagosoma formation, as well as cytokine gene expression and production. Cultures exposed to cortisol showed a decreased production of IL-1β, TNF-α, with DHEA being unable to modify the pattern of cytokine production or to reverse the cortisol inhibitory effects. Interestingly the intra-macrophagic bacterial burden was found reduced by DHEA treatment. While this effect was not related to a different cytokine pattern, in terms their production or mRNA expression, DHEA treatment did promote autophagy in Mtb-infected macrophages, irrespective of Cortisol presence. In essence, the better control of Mtb load by DHEA-treated macrophages seems to be dependent on an autophagic mechanism. The present results are relevant for two reasons as autophagy is not only important for clearance of mycobacteria but also for the prevention of tissue damage.

Functional characterization of a competitive peptide antagonist of p65 in human macrophage-like cells suggests therapeutic potential for chronic inflammation.

Glucocorticoid-induced leucine zipper (GILZ) is a glucocorticoid responsive protein that links the nuclear factor-kappa B (NFκB) and the glucocorticoid signaling pathways. Functional and binding studies suggest that the proline-rich region at the carboxy terminus of GILZ binds the p65 subunit of NFκB and suppresses the immunoinflammatory response. A widely-used strategy in the discovery of peptide drugs involves exploitation of the complementary surfaces of naturally occurring binding partners. Previously, we observed that a synthetic peptide (GILZ-P) derived from the proline-rich region of GILZ bound activated p65 and ameliorated experimental encephalomyelitis. Here we characterize the secondary structure of GILZ-P by circular dichroic analysis. GILZ-P adopts an extended polyproline type II helical conformation consistent with the structural conformation commonly observed in interfaces of transient intermolecular interactions. To determine the potential application of GILZ-P in humans, we evaluated the toxicity and efficacy of the peptide drug in mature human macrophage-like THP-1 cells. Treatment with GILZ-P at a wide range of concentrations commonly used for peptide drugs was nontoxic as determined by cell viability and apoptosis assays. Functionally, GILZ-P suppressed proliferation and glutamate secretion by activated macrophages by inhibiting nuclear translocation of p65. Collectively, our data suggest that the GILZ-P has therapeutic potential in chronic CNS diseases where persistent inflammation leads to neurodegeneration such as multiple sclerosis and Alzheimer’s disease.

Listeria monocytogenes isolated from food samples from a Romanian black market show distinct virulence profiles

Listeria monocytogenes is a facultative intracellular foodborne pathogen responsible for listeriosis. In a recent study, in which we investigated neglected exogenous routes of transmission of foodborne pathogens into the European Union, we have isolated 15 L. monocytogenes strains in food products, which were imported from the Republic of Moldavia to Romania and illegally sold at a local market.The aim of this study was to characterize the subtype and virulence potential of these 15 L. monocytogenes strains. Multilocus sequence typing revealed that these L. monocytogenes strains belong to six different sequence types (ST2, ST8, ST9, ST20, ST121 and ST155). In addition, in vitro virulence assays using human intestinal epithelial Caco2 and macrophage-like THP1 cells showed a high strain variability regarding the invasion efficiency in Caco2 cells (0.98–2.78%) and the intracellular growth rate in both cell types. Both ST121 strains and the ST9 isolate were unable to invade Caco2 cells, and all ST155 strains showed no proliferation inside macrophages and revealed low cytotoxicity. Furthermore we performed sequence analysis of three main virulence factors: PrfA, internalin A (InlA) and listeriolysin O (LLO). The Romanian food isolates showed a high diversity in the InlA and LLO amino acid sequences, whereas the amino acid sequence of PrfA of all strains was identical. Overall, the amino acid sequences of PrfA, InlA and LLO were identical for strains belonging to the same ST. We detected in total 30 different amino acid substitutions, resulting in seven different InlA variants, two of which have not yet been described. The three strains, which were unable to invade Caco2 cells, harboured a premature stop codon resulting in truncated InlA. Furthermore, we detected four different amino acid substitutions in the LLO sequence, which are present in four variants. The number of LLO mutations correlates negatively with intracellular growth in Caco2 and THP1 cells and subsequently with cytotoxicity.In conclusion, we show that L. monocytogenes isolated from food samples from a Romanian black market show distinct virulence profiles, due to a high diversity in the amino acid sequence of main virulence factors.

Intrauterine Group A Streptococcal Infections Are Exacerbated by Prostaglandin E2

Streptococcus pyogenes (Group A Streptococcus; GAS) is a major cause of severe postpartum sepsis, a re-emerging cause of maternal morbidity and mortality worldwide. Immunological alterations occur during pregnancy to promote maternofetal tolerance, which may increase the risk for puerperal infection. PGE2 is an immunomodulatory lipid that regulates maternofetal tolerance, parturition, and innate immunity. The extent to which PGE2 regulates host immune responses to GAS infections in the context of endometritis is unknown. To address this, both an in vivo mouse intrauterine (i.u.) GAS infection model and an in vitro human macrophage-GAS interaction model were used. In C57BL/6 mice, i.u. GAS inoculation resulted in local and systemic inflammatory responses and triggered extensive changes in the expression of eicosanoid pathway genes. The i.u. administration of PGE2 increased the mortality of infected mice, suppressed local IL-6 and IL-17A levels, enhanced neutrophilic inflammation, reduced uterine macrophage populations, and increased bacterial dissemination. A role for endogenous PGE2 in the modulation of antistreptococcal host defense was suggested, because mice lacking the genes encoding the microsomal PGE2 synthase-1 or the EP2 receptor were protected from death, as were mice treated with the EP4 receptor antagonist, GW627368X. PGE2 also regulated GAS-macrophage interactions. In GAS-infected human THP-1 (macrophage-like) cells, PGE2 inhibited the production of MCP-1 and TNF-α while augmenting IL-10 expression. PGE2 also impaired the phagocytic ability of human placental macrophages, THP-1 cells, and mouse peritoneal macrophages in vitro. Exploring the targeted disruption of PGE2 synthesis and signaling to optimize existing antimicrobial therapies against GAS may be warranted.

Abstract 620: Angiotensin AT2 Receptor Exerts an Anti-inflammatory Response in Lipopolysaccharide-activated THP-1 Macrophages

Macrophages have been shown to be an important contributor to the pathogenesis of hypertension and stroke. The angiotensin AT2 receptor (AT2R), which is expressed in macrophages, is known to promote vasodialation, natriuresis and lower inflammation. The goal of the present study was to explore the anti-inflammatory role of AT2R stimulation in human macrophage-like THP-1 cells activated by lipopolysaccharide (LPS). Phorbol 12-myristate 13-acetate (PMA) differentiated macrophage-like THP-1 cells were treated with AT2R agonist C21 (1 μmol/L) for 30 minutes prior to activation with LPS (1 μg/ml). Media and cells were collected after 24 hours and were analyzed for levels of pro- and anti-inflammatory cytokines and proteins. Pre-treatment with C21 resulted in a 4-fold increase (104.8±6.1 vs 406.7±52.3) in anti-inflammatory interleukin-10 (IL-10) production and a 5-fold decrease (3560±237 vs 588.8±15.94) in pro-inflammatory tumor necrosis factor-α (TNF-α) levels in the media in response to LPS. Predictably, LPS resulted in a 6-fold up-regulation of iNOS expression which was prevented with C21 pre-treatment. A modest decrease in the anti-inflammatory macrophage mannose receptor C type 2 (MRC2) expression was detected with LPS treatment. AT2R agonist pre-treatment, however, increased this receptor expression by ~70% after LPS activation. C21 alone also resulted in a 20% increase in MRC2 expression compared to untreated controls. The anti-inflammatory effect of AT2R activation was abolished in the presence of neutralizing IL-10 antibody (1 μg/ml), indicating a central role for IL-10 in mediating the beneficial response to C21 in LPS activated macrophages. Further, inhibition of nitric oxide (NO) by L-NAME prior to C21 pre-treatment also prevented the decrease in TNF-α and increase in IL-10 in response to AT2R agonist, which suggests that the anti-inflammatory response to C21 may be mediated via increase in NO production prior to LPS activation of macrophages. In conclusion, AT2R stimulation may potentially suppress the inflammatory response of macrophages to LPS by shifting the balance from pro- to anti-inflammatory cytokine production and may prove to be beneficial in the control of the inflammatory component of stroke and hypertension.

Macrophages facilitate coal tar pitch extract-induced tumorigenic transformation of human bronchial epithelial cells mediated by NF-κB.

ObjectiveChronic respiratory inflammation has been associated with lung cancer. Tumor-associated macrophages (TAMs) play a critical role in the formation of inflammation microenvironment. We sought to characterize the role of TAMs in coal tar pitch extract (CTPE)-induced tumorigenic transformation of human bronchial epithelial cells and the underlying mechanisms.MethodsThe expression of TAMs-specific CD68 in lung cancer tissues and paired adjacent tissues from cancer patients was determined using immunostaining. Co-culture of human bronchial epithelial cells (BEAS-2B) and macrophage-like THP-1 cells were conducted to evaluate the promotive effect of macrophages on CTPE-induced tumorigenic transformation of BEAS-2B cells. BEAS-2B cells were first treated with 2.4 µg/mL CTPE for 72 hours. After removal of CTPE, the cells were continuously cultured either with or without THP-1 cells and passaged using trypsin-EDTA. Alterations of cell cycle, karyotype, colony formation in soft agar and tumor xenograft growth in nude mice of BEAS-2B cells at passages 10, 20 and 30, indicative of tumorigenecity, were determined, respectively. In addition, mRNA and protein levels of NF-κB in BEAS-2B cells were measured with RT-PCR and western blot, respectively. B(a)P was used as the positive control.ResultsThe over-expression of TAMs-specific CD68 around lung tumor tissues was detected and associated with lung cancer progression. The tumorigenic alterations of BEAS-2B cells including increase in cell growth rate, number of cells with aneuploidy, clonogenicity in soft agar, and tumor size in nude mice in vivo occurred at passage 10, becoming significant at passages 20 and 30 of the co-culture following CTPE removal in compared to BEAS-2B cells alone. In addition, the expression levels of NF-κB in BEAS-2B cells were positively correlated to the malignancy of BEAS-2B cells under different conditions of treatment.ConclusionThe presence of macrophages facilitated CTPE-induced tumorigenic transformation of BEAS-2B cells, which may be mediated by NF-κB.