Iopromide in combination with IFN-γ induces the activation of HMC-1 cells via IL-4 and MCP-1 expression.

In this study, we investigated whether IFN-γ has a role in contrast-medium-induced adverse reactions. Iopromide, a nonionic iodinated contrast agent, slightly induced mast cell proliferation and significantly increased the expression of IL-4 and MCP-1 at low doses. The pretreatment of cells with IFN-γ dramatically increased the expression of iopromide-induced IL-4 and MCP-1. An evaluation of mast cell activator secretion revealed that IFN-γ- or IL-4-pretreated HMC-1 cells released dramatically increased levels of ß-hexosaminidase and histamine when stimulated with iopromide. We also found that the migration of EoL-1 and THP-1 cells was significantly increased in culture conditions with iopromide-stimulated IL-4-pretreated HMC-1 cells. Taken together, our findings suggest that measuring IFN-γ or IL-4 levels in serum would be helpful as a potential biomarker of adverse patient reactions and that blocking IFN-γ or IL-4 may be crucial in preventing the delayed allergy-like reaction induced by contrast medium in patients with various diseases.

Surgical Management of Edentulous Atrophic Mandible Fractures in the Elderly.

Fractures of the mandible occur with a greater frequency in the elderly. This study reports three cases of edentulous atrophic mandible fracture in elderly patients treated with open reduction technique. Three patients who presented with edentulous atrophic mandible fractures underwent surgical management using open reduction and internal fixation. After treatment, clinical evaluations and postoperative complications were examined with postoperative x-ray. Patients were followed with clinical and radiographic examinations. In the postoperative clinical evaluation, two male patients healed well, but one female patient complained of pain and swelling. In radiographic examinations, no union delay or lack of fusion was observed in the edentulous area. Open reduction technique is a viable treatment option for the edentulous atrophic mandible fractures in geriatric patients.

All-trans retinoic acid induces TLR-5 expression and cell differentiation and promotes flagellin-mediated cell functions in human THP-1 cells.

Toll-like receptor 5 (TLR-5), which is expressed on macrophages and dendritic cells (DCs), is a crucial cell surface molecule that senses microbial-associated molecular patterns and initiates host innate immune responses upon infection with invaders that express flagellin. Little information is known about the induction factors and mechanisms of TLR-5 expression. In this study, we demonstrate that all-trans retinoic acid (ATRA) significantly up-regulated TLR-5 expression in human macrophage THP-1 cells by co-activating NF-κB and the RARα receptor and inducing the differentiation of CD11b(-)CD11c(-) THP-1 cells to CD11b(+)CD11c(low) cells. Furthermore, when stimulated with flagellin, ATRA-induced THP-1 cells expressed multiple cytokines, including TNF-α, IL-1beta, and IL-12p40, and several co-stimulatory molecules, such as CD40, CD80, CD86, and MHC class I and II. We also showed that when ATRA-induced THP-1 cells were stimulated with flagellin, the cells displayed an allostimulatory capacity rather than phagocytic activity. Taken together, our findings suggest that ATRA is a crucial immunostimulatory cofactor that induces the activation of macrophages and their subsequent differentiation into dendritic-like cells.

Accumulation of VEGFR2 in zoledronic acid-treated endothelial cells.

Nitrogen-containing bisphosphonates (BIS) are potent inhibitors of bone resorption and are used in the treatment of a number of medical conditions, including multiple myeloma, breast cancer and osteoporosis. Recent experimental evidence demonstrates that BIS also affect endothelial cell functions and angiogenesis; however, the molecular mechanism(s) are unclear. Vascular endothelial growth factor (VEGF) is a potent pro-angiogenic signal for endothelial cells. BIS inhibit VEGF responses in endothelial cells. The VEGF receptor-2 (VEGFR2) is the main signaling receptor for VEGF in endothelial cells. We hypothesized that altered VEGFR2 expression in BIS-treated endothelial cells may account for these attenuated responses to VEGF. The affect of the BIS zoledronic acid (ZOL) was investigated in human umbilical vein endothelial cells using confocal microscopy, Western blotting, real-time PCR and flow cytometry. VEGFR2 accumulated within the ZOL-treated endothelial cells (p=0.0002), though not on the cell surface (p>0.05). ZOL did not induce VEGFR2-specific mRNA (p>0.05). ZOL inhibited endothelial cell chemotaxis towards VEGF (p=0.001). VEGF stimulation significantly reduced the amount of VEGFR2 in the endothelial cells (p=0.01). This response to VEGF was reduced by ZOL (p>0.05). The effects of ZOL on endothelial cell migration, VEGFR2 protein expression and response to VEGF were attenuated by geranylgeranyl pyrophosphate. Two- and one-way ANOVAs with Tukey or Dunnett's multiple comparison adjustments were used. The data suggest that ZOL induces aberrant VEGFR2 accumulation. This is not likely due to the induction of mRNA transcription, but rather to the disruption of the mevalonate pathway.

Programmed death-1 receptor negatively regulates LPS-mediated IL-12 production and differentiation of murine macrophage RAW264.7 cells.

While programmed death-1 (PD-1), a co-inhibitory member of CD28 immunoglobulin superfamily plays negative roles in effector functions of T cells and B cells, little is known about the function of PD-1 expressed on innate immune cells. In this study, we demonstrate that IL-12 production was greatly suppressed in LPS-stimulated RAW264.7 cells upon PD-1 engagement with B7-H1.Fc fusion protein, and was restored in the presence of antagonistic anti-PD-1 mAb. PD-1-mediated suppression of IL-12 production in LPS-stimulated RAW264.7 cells was mediated by inhibition of Janus N-terminal-linked kinase (JNK) signaling pathway, and to a lesser extent, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway through the recruitment of SHP-2 to PD-1 cytoplasmic tail. B7-H1.Fc-mediated PD-1 engagement also downregulates the expression of co-stimulatory molecules such as CD80, CD86, MHC class I and II proteins in LPS-stimulated RAW264.7 cells. Furthermore, the endocytic activity is enhanced but the allostimulatory capacity is suppressed in LPS-treated RAW264.7 cells upon PD-1 engagement. Taken together, our results reveal a novel function of macrophage PD-1 in the negative regulation of IL-12 synthesis and differentiation into dendritic cell-like cells.

Interferon-sensitive response element (ISRE) is mainly responsible for IFN-alpha-induced upregulation of programmed death-1 (PD-1) in macrophages.

Programmed death-1 (PD-1), an immunoinhibitory receptor, is upregulated in T cells, B cells, NKT cells, and monocytes upon activation. More specifically, T-cell-associated PD-1 is critically important for maintaining peripheral tolerance through the PD-1-B7-H1 pathway. However, the physiological role of macrophage-associated PD-1 remains unclear. We addressed the molecular mechanism underlying the regulation of PD-1 expression on macrophages in response to IFN-alpha. Based on a luciferase assay using promoter constructs, we found that the promoter region located between -1090 and -1105 nucleotides from the translational start site is essential for PD-1 expression. Electrophoretic mobility-shift assay and site-directed mutagenesis revealed that interferon-sensitive responsive element (ISRE) and STAT1 and STAT2 are primarily responsible for the constitutive expression of PD-1, as well as for the IFN-alpha-mediated upregulation of PD-1. In addition, AG490, a Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) inhibitor, markedly abolished the responsiveness of bone marrow-derived macrophages (BMM) to IFN-alpha. Our findings support the essential roles of ISRE, STAT1, and STAT2 in the regulation of constitutive and IFN-alpha-mediated PD-1 expression in macrophages.