Effects of IFNγ and IL4 rich microenvironment on porcine monocyte-derived dendritic cell activation in vitro.

Dendritic cells (DCs) represent a heterogeneous group of major antigen-presenting cells, responding to different stimuli in their microenvironment. They are able to activate naïve T-cells and drive their polarization towards effector types. However, the effect of different Th-polarizing cytokine microenvironment on porcine DCs remains poorly described. Therefore, the effect of IFNγ or IL4 rich microenvironment on porcine monocyte-derived dendritic cells and their activation, antigen recognition and cytokine secretion towards T-cell polarization were studied in vitro. IFNγ-rich microenvironment induced a higher proinflammatory response and release of Th1/Th17-polarizing cytokines (IL1ß, IL12p35, IL23p19), while anti-inflammatory properties (IL10, TGFß) was not affected by a cytokine microenvironment. From the achieved results, we propose that different cytokine microenvironment has the potential to modulate dendritic cells and their ability to activate T-cells.

Bovine lactoferrin free of lipopolysaccharide can induce a proinflammatory response of macrophages.

BACKGROUND: Lactoferrin (LF) is an 80 kDa glycoprotein which is known for its effects against bacteria, viruses and other pathogens. It also has a high potential in nutrition therapy and welfare of people and a variety of animals, including piglets. The ability to bind lipopolysaccharide (LPS) is one of the described anti-inflammatory mechanisms of LF. Previous studies suggested that cells can be stimulated even by LPS-free LF. Therefore, the aim of our study was to bring additional information about this possibility. Porcine monocyte derived macrophages (MDMF) and human embryonic kidney (HEK) cells were stimulated with unpurified LF in complex with LPS and with purified LF without bound LPS. RESULTS: Both cell types were stimulated with unpurified as well as purified LF. On the other hand, neither HEK0 cells not expressing any TLR nor HEK4a cells transfected with TLR4 produced any pro-inflammatory cytokine transcripts after stimulation with purified LF. This suggests that purified LF without LPS stimulates cells via another receptor than TLR4. An alternative, TLR4-independent, pathway was further confirmed by analyses of the NF-kappa-B-inducing kinase (NIK) activation. Western blot analyses showed NIK which activates different NFκB subunits compared to LF-LPS signaling via TLR4. Though, this confirmed an alternative pathway which is used by the purified LF free of LPS. This stimulation of MDMF led to low, but significant amounts of pro-inflammatory cytokines, which can be considered as a positive stimulation of the immune system. CONCLUSION: Our results suggest that LF's ability is not only to bind LPS, but LF itself may be a stimulant of pro-inflammatory pathways.

Evaluation of in vitro and in vivo anti-inflammatory activity of biologically active phospholipids with anti-neoplastic potential in porcine model.

BACKGROUND: This study aims to investigate the anti-inflammatory effect of biologically active phospholipids (BAP) used in preparations for clinical practice in humans. Until date, except anti-neoplastic ability, little is known about anti-inflammatory property of the phospholipids. METHODS: While the course of bacterially induced acute pneumonia and markers of inflammation were studied in in vivo system in pigs orally supplemented with BAP, the pro- and anti-inflammatory response of lipopolysaccharide-stimulated porcine monocyte-derived macrophages to 24 h- and 48 h-treatment by BAP was investigated in in vitro system. In vivo, the animal health status was monitored and pro-inflammatory IL-1ß and IL-8 in sera were detected by ELISA during the experiment, while bronchoalveolar lavage fluids (BALF) and the lungs were examined post-mortem. Total and differential counts of white blood cell (WBC) were determined in blood and BALF. In vitro, mRNA expression of pro-inflammatory (TNF-α, IL-1ß, CXCL10) and anti-inflammatory (IL-10 and Arg1) cytokines, and level of activated caspase 1 and phosphorylated protein kinase C epsilon (pPKCϵ), were studied using qRT-PCR and Western blot, respectively. For the purposes of both systems, 6 animals were used in each of the BAP-supplemented and the control groups. RESULTS: In vivo, BAP had a positive influence on the course of the disease. The immunomodulatory effects of BAP were confirmed by lower levels of IL-1ß, IL-8, and a lower WBC count in the supplemented group in comparison with the control group. A lower percentage of lung parenchyma was affected in the supplemented group comparing to the control group (on average, 4% and 34% of tissue, respectively). In vitro, BAP suppressed mRNA expression of mRNA for IL-10 and all pro-inflammatory cytokines tested. This down-regulation was dose- and time-dependent. Arg1 mRNA expression remained unaffected. Further dose- and time-dependent suppression of the activated caspase 1 and pPKCϵ was detected in macrophages when treated with BAP. CONCLUSIONS: Our results demonstrate that BAP has anti-inflammatory and immunomodulatory properties, thus emphasizing the potential of this compound as a natural healing agent.

Immune response of pigs to Salmonella enterica serovar Derby and Typhimurium infections.

Interaction between pigs and Salmonella enterica serovar Derby (Salmonella Derby) is much less understood in comparison with Salmonella enterica serovar Typhimurium (Salmonella Typhimurium). To study interactions of weaned piglets with Salmonella Derby, we compared the course of infections with Salmonella Derby De1 and Salmonella Typhimurium DT104 strains, both isolated from pig herds with a long history of asymptomatic infection. Salmonella Derby strain used was shed during the 28-day experiment period, while Salmonella Typhimurium strain was not found in faeces after day 17 post-infection. When the piglets were co-infected with both strains, Salmonella Derby was present in faeces until the end of the experiment, whilst Salmonella Typhimurium disappeared after day 21 post-infection. At the end of the experiment, Salmonella Derby was present in more tissues when compared with Salmonella Typhimurium. Piglets infected with Salmonella Typhimurium responded earlier with synthesis of anti-lipopolysaccharide IgM and IgG antibodies and with higher antibody levels compared to piglets infected with Salmonella Derby. Cellular immune response to both strains was very low and was detected later than was the onset of IgG antibody production.

Apoptosis inhibitor 5 (API-5; AAC-11; FIF) is upregulated in human carcinomas in vivo.

Apoptosis inhibitor 5 (API-5) is a 55 kDa nuclear protein with potent anti-apoptotic signaling in tumor cells in vitro. In this study, we analyzed the expression of the API-5 protein in vivo in a broad spectrum of human carcinomas, including those of the colon, lung, liver, kidney, pancreas, stomach and esophagus using tumor tissues obtained during tumor resection. The results showed significant upregulation of API-5 expression in biopsies of lung (23%, n=13) and colorectal tumors (33%, n=27) in comparison with biopsies from the adjacent normal tissue. Colon cancer biopsies were used to study the cell populations with an upregulated level of expression of API-5 more closely. Using a magnetic bead-based selection for the epithelial cell marker EpCAM, we purified epithelial cells from the tumor and control tissues and analyzed these cells for API-5 expression by western immunoblotting. We observed that EpCAM-positive tumor cells expressed API-5 in all three colorectal cancer cases tested, in contrast to the control EpCAM-positive and EpCAM-negative cells isolated from the control or tumor tissues. These data suggest that the expression of the API-5 protein is upregulated in tumor epithelial cells and may serve as a prognostic marker in colorectal cancer.

CD4+ and γδTCR+ T lymphocytes are sources of interleukin-17 in swine.

In the veterinary field, only limited information is available about interleukin-17A (IL-17), despite the fact that this cytokine plays an important role during pro-inflammatory immune responses and induces the production of chemotactic factors for neutrophils. The aim of this study was to characterize porcine IL-17-producing cells. We tested the cross-reactivity of five anti-human IL-17 monoclonal antibodies because such antibodies against porcine IL-17 are currently unavailable. Whole blood cells (WBCs) were stimulated with phorbol-myristate-acetate (PMA) and ionomycin and subsequently analyzed by flow cytometry. The antibody clone SCPL1362 was found to cross-react with porcine IL-17, whereas the other four antibodies tested did not recognize this cytokine. Using this antibody, we characterized porcine WBC-secreting IL-17 after PMA and ionomycin stimulation. All IL-17-producing WBCs were positive for the T lymphocyte marker CD3. Myeloid cells (CD172α(+)) and B lymphocytes (CD79α(+)) were IL-17 negative. The major subset of IL-17 positive T lymphocytes was the CD4(+) lymphocytes (about 60% of all IL-17 positive WBCs). The remaining IL-17 positive WBCs were γδTCR(+) lymphocytes. CD8 positive and CD8 negative cells were found within both CD4(+) and γδTCR(+) cells producing the cytokine. Moreover, IL-17 positive cells were mostly CD45RA negative, therefore activated cells or memory cells. Flow cytometry data were confirmed using sorted cells. Both sorted CD4(+) and γδTCR(+) cells produced IL-17 at mRNA level after PMA and ionomycin stimulation while double negative CD4(-)γδTCR(-) cells were negative for IL-17. We can conclude that only two subpopulations of porcine WBCs are sources of IL-17 after non-specific stimulation: CD3(+)CD4(+) and CD3(+)γδTCR(+).

NF449 is a novel inhibitor of fibroblast growth factor receptor 3 (FGFR3) signaling active in chondrocytes and multiple myeloma cells.

The FGFR3 receptor tyrosine kinase represents an attractive target for therapy due to its role in several human disorders, including skeletal dysplasias, multiple myeloma, and cervical and bladder carcinomas. By using molecular library screening, we identified a compound named NF449 with inhibitory activity toward FGFR3 signaling. In cultured chondrocytes and murine limb organ culture, NF449 rescued FGFR3-mediated extracellular matrix loss and growth inhibition, which represent two major cellular phenotypes of aberrant FGFR3 signaling in cartilage. Similarly, NF449 antagonized FGFR3 action in the multiple myeloma cell lines OPM2 and KMS11, as evidenced by NF449-mediated reversal of ERK MAPK activation and transcript accumulation of CCL3 and CCL4 chemokines, both of which are induced by FGFR3 activation. In cell-free kinase assays, NF449 inhibited the kinase activity of both wild type and a disease-associated FGFR3 mutant (K650E) in a fashion that appeared non-competitive with ATP. Our data identify NF449 as a novel antagonist of FGFR3 signaling, useful for FGFR3 inhibition alone or in combination with inhibitors that target the ATP binding site.

FGFR3 signaling induces a reversible senescence phenotype in chondrocytes similar to oncogene-induced premature senescence.

Oncogenic activation of the RAS-ERK MAP kinase signaling pathway can lead to uncontrolled proliferation but can also result in apoptosis or premature cellular senescence, both regarded as natural protective barriers to cell immortalization and transformation. In FGFR3-related skeletal dyplasias, oncogenic mutations in the FGFR3 receptor tyrosine kinase cause profound inhibition of cartilage growth resulting in severe dwarfism, although many of the precise mechanisms of FGFR3 action remain unclear. Mutated FGFR3 induces constitutive activation of the ERK pathway in chondrocytes and, remarkably, can also cause both increased proliferation and apoptosis in growing cartilage, depending on the gestational age. Here, we demonstrate that FGFR3 signaling is also capable of inducing premature senescence in chondrocytes, manifested as reversible, ERK-dependent growth arrest accompanied by alteration of cellular shape, loss of the extracellular matrix, upregulation of senescence markers (alpha-GLUCOSIDASE, FIBRONECTIN, CAVEOLIN 1, LAMIN A, SM22alpha and TIMP 1), and induction of senescence-associated beta-GALACTOSIDASE activity. Our data support a model whereby FGFR3 signaling inhibits cartilage growth via exploiting cellular responses originally designed to eliminate cells harboring activated oncogenes.

Analysis of STAT1 activation by six FGFR3 mutants associated with skeletal dysplasia undermines dominant role of STAT1 in FGFR3 signaling in cartilage.

Activating mutations in FGFR3 tyrosine kinase cause several forms of human skeletal dysplasia. Although the mechanisms of FGFR3 action in cartilage are not completely understood, it is believed that the STAT1 transcription factor plays a central role in pathogenic FGFR3 signaling. Here, we analyzed STAT1 activation by the N540K, G380R, R248C, Y373C, K650M and K650E-FGFR3 mutants associated with skeletal dysplasias. In a cell-free kinase assay, only K650M and K650E-FGFR3 caused activatory STAT1(Y701) phosphorylation. Similarly, in RCS chondrocytes, HeLa, and 293T cellular environments, only K650M and K650E-FGFR3 caused strong STAT1 activation. Other FGFR3 mutants caused weak (HeLa) or no activation (293T and RCS). This contrasted with ERK MAP kinase activation, which was strongly induced by all six mutants and correlated with the inhibition of proliferation in RCS chondrocytes. Thus the ability to activate STAT1 appears restricted to the K650M and K650E-FGFR3 mutants, which however account for only a small minority of the FGFR3-related skeletal dysplasia cases. Other pathways such as ERK should therefore be considered as central to pathological FGFR3 signaling in cartilage.