Downregulation of Tumor Necrosis Factor Expression in the Human Mono-Mac-6 Cell Line

Mono-Mac-6 cells, but not U937 cells, can be Induced to rapidly express tumor necrosis factor (TNF) mRNA and protein when triggered with Ilpopolysaccharlde (LPS) at 1 pg/mI. Preincubatlon of the cells for 3 d with low amounts of LPS (10 ng/mI) results In nearly complete suppression of TNF secretion. This downreguiatlon appears to occur at the pretranslational level since specIfIc mRNA is virtually undetectable under these conditions. By contrast, the same prelncubatlon with 10 ng/mI LPS results in enhanced phagocytosls (28.6-67.2% for Staphylococcus aureus), demonstrating that not all monocyte functions are suppressed. While these results show that only stringent exclusion of LPS from culture media allows for Induction of TNF In the Mono-Mac-6 cell line, the pronounced effect of LPS preincubatlon may also provide a suitable model with which to study the mechanisms of LPS-lnduced desensitizatIon

Recombinant IFN-α in Lymphomas

The effectiveness of interferon (IFN) therapy in malignant lymphoma is analyzed in this review. Although various treatment regimens including IFN at various dose levels have so far not proved to have curative potential, a substantial palliative effect has been noted in hairy-cell leukemia and in some non-Hodgkin lymphomas of low-grade malignancy. Early stages of lymphoma disease are more responsive to IFN therapy, and this holds true also for chronic lymphocytic leukemia, in which IFN treatment is usually not effective in progressed disease after chemotherapy. Concepts of early-phase treatment and of remission maintenance by using IFN therapy are discussed on the basis of the data from several studies

The macrophage in cystic fibrosis

Background: Cystic fibrosis (CF) is caused by absent/defective CF transmembrane conductance regulator protein (CFTR). CF is characterized by thick airway mucus, chronic infection and neutrophil inflammation leading to respiratory failure. I analysed airway macrophages (MΦs) and their expression of pattern recognition receptors (PRRs) in CF, since these cells are crucial to airway immune defence and they can orchestrate inflammation. I also performed transcript analysis of CF monocyte-derived MΦs (MDMs). Methods: Sputum was induced in CF paediatric and adult cohorts. Phenotype and function of CF MΦ were determined by flow cytometry and compared to controls. Monocytes (>92% purity) were grown in vitro to generate MDMs (n=15). Transcripts encoding the entire human genome were analysed (n=5) and expression of individual genes were confirmed by RT-PCR. Results: In classical CF (n=10) there was an increase in the proportion of monocyte-like small MΦs (of total MΦ) compared to controls (n=10) (73 ± 18% and 16 ± 8%, respectively, p0.05). PRRs were absent on small MΦs from CF and control. In contrast, clear expression could be detected on large MΦs from control but not CF. In line with this, CF small MΦs showed a strongly reduced uptake of particles compared to controls. Microarray analysis of MDMs revealed α- and β-tryptase as being significantly higher under constitutive and stimulated conditions in CF compared to control. However, using RT-PCR, expression of α- and β-tryptase was similar between groups. Conclusions: The phenotype of small MΦs in CF suggests that these cells are newly recruited monocytes from blood. Low expression of PRRs on these cells in CF and their reduced uptake indicates a reduced capacity to clear inhaled particles, which may contribute to further damage in CF. Further to this I was unable to confirm any transcript differences between CF and control MDMs due to mutant CFTR.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Expression of p57-Kip2 in monocytes and macrophages

The p57-Kip2 gene encodes a cyclin-dependent kinase inhibitor and hence this gene has received much attention in the study of malignancy. We have analysed expression of this gene in human monocytes and macrophages. In comparison to CD14++ monocytes, p57-Kip2 expression was higher in both CD14+16+ monocytes and alveolar macrophages. p57-Kip2 expression decreased in CD14++ monocytes after stimulation with lipopolysaccharide but increased after incubation with methylprednisolone. The results indicate that p57-Kip2 may be involved in regulating the inflammatory response of monocytic cell

All-trans retinoic acid up-regulates Prostaglandin-E synthase expression in human macrophages

All-trans retinoic acid (ATRA) is a potent retinoid, which has been used successfully in different clinical settings as a potential drug to treat COPD and emphysema. In the present study, we analyzed genes modulated by ATRA by performing mRNA expression array analysis on alveolar macrophages after treatment with ATRA. Here we observed a 375-fold up-regulation of Prostaglandin-E Synthase (microsomal PGES-1, NM_004878 PTGES) which mediates the conversion of prostaglandin H(2) (PGH(2)) to Prostaglandin E(2) (PGE(2)). We furthermore studied the expression of PTGES after treatment with ATRA in human monocyte-derived macrophages (MDMs) and bronchoalveolar lavage (BAL) cells. ATRA up-regulated PTGES mRNA expression in MDMs generated with M-CSF by 2500-fold whereas in M-CSF+IL-13 macrophages the up-regulation was only 20-fold. Similarly, ATRA up-regulated PTGES mRNA expression by factor 1524 in BAL cells. The up-regulation of PTGES mRNA expression by ATRA is both time and dose dependent. IL-13 suppressed the ATRA induced PTGES expression at both mRNA and protein level in MDM and BAL cells. We also observed that LPS acts synergistically with ATRA in MDMs and strongly induces PTGES expression. ATRA had little impact on cyclooxygenase-1 and -2 (COX-1 and -2) expression as compared to PTGES expression under the same experimental conditions. Furthermore, we observed an induction of PGE(2) levels by ATRA in BAL cells. These data indicate that ATRA is a potent inducer of PTGES expression in human macrophages but not in alternatively activated macrophages and suggest that the eicosanoid pathway is important for ATRA action in macrophages