Anti-inflammatory effects of moxifloxacin on IL-8, IL-1beta and TNF-alpha secretion and NFkappaB and MAP-kinase activation in human monocytes stimulated with Aspergillus fumigatus.

OBJECTIVES: We have previously shown that moxifloxacin conferred protective anti-inflammatory effects against Candida pneumonia in immunosuppressed mice. Further in vitro studies showed anti-inflammatory effects of moxifloxacin in LPS and cytokine-stimulated monocytic and epithelial cells. In the present study, concentrating on a more challenging pathogen of immunosuppressed hosts, we studied the effect of moxifloxacin on cytokine secretion and signal transduction mechanisms in monocytic cells stimulated with Aspergillus fumigatus. METHODS: Human peripheral blood monocytes (PBMCs) and a human monocytic cell line (THP-1) were incubated with 1.5x10(6)/mL conidia of a clinical isolate of A. fumigatus. Cytokine secretion and activation of NFkappaB and the MAP-kinases ERK1/2 and p38 were measured with and without the addition of moxifloxacin (5-20 mg/L). RESULTS: Stimulation of PBMCs and THP-1 cells with A. fumigatus increased IL-8, IL-1beta and TNF-alpha secretion (4.1-, 8.3- and 7-fold, and 5.4-, 3.7- and 17.8-fold, respectively). Addition of moxifloxacin (5-20 mg/L) inhibited cytokine secretion up to 45.7+/-5%, 72+/-13% and 73+/-10% in PBMCs and up to 35.6+/-0.5%, 30+/-2.4% and 19+/-4% in THP-1 cells (P<0.05). Signal transduction studies showed that incubation of THP-1 cells with A. fumigatus increased ERK1/2 and p38 phosphorylation and p65-NFkappaB protein expression by 1.6-, 1.3- and 1.8-fold, respectively. Addition of moxifloxacin inhibited ERK1/2, p38 and p65-NFkappaB by up to 69+/-14%, 58+/-3% and 75+/-15%, respectively. CONCLUSIONS: Our results indicate that moxifloxacin acts as an anti-inflammatory agent in monocytic cells stimulated with A. fumigatus conidia. Whether these effects may be protective as in the Candida pneumonia model is unknown and merits in vivo studies in models of pulmonary aspergillosis.

Anti-inflammatory effects of moxifloxacin on activated human monocytic cells: inhibition of NF-kappaB and mitogen-activated protein kinase activation and of synthesis of proinflammatory cytokines.

We previously showed that moxifloxacin (MXF) exerts protective anti-inflammatory effects in immunosuppressed mice infected with Candida albicans by inhibiting interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-alpha) production in the lung. Immunohistochemistry demonstrated inhibition of nuclear factor (NF)-kappaB translocation in lung epithelium and macrophages in MXF-treated mice. In the present study we investigated the effects of MXF on the production of proinflammatory cytokines (i.e., IL-8, TNF-alpha, and IL-1beta) by activated human peripheral blood monocytes and THP-1 cells and analyzed the effects of the drug on the major signal transduction pathways associated with inflammation: NF-kappaB and the mitogen-activated protein kinases ERK and c-Jun N-terminal kinase (JNK). The levels of IL-8, TNF-alpha, and IL-1beta secretion rose 20- and 6.7-fold in lipopolysaccharide (LPS)-activated monocytes and THP-1 cells, respectively. MXF (5 to 20 microg/ml) significantly inhibited cytokine production by 14 to 80% and 15 to 73% in monocytes and THP-1 cells, respectively. In THP-1 cells, the level of NF-kappaB nuclear translocation increased fourfold following stimulation with LPS-phorbol myristate acetate (PMA), and this was inhibited (38%) by 10 microg of MXF per ml. We then assayed the degradation of inhibitor (I)-kappaB by Western blotting. LPS-PMA induced degradation of I-kappaB by 73%, while addition of MXF (5 microg/ml) inhibited I-kappaB degradation by 49%. Activation of ERK1/2 and the 46-kDa p-JNK protein was enhanced by LPS and LPS-PMA and was significantly inhibited by MXF (54 and 42%, respectively, with MXF at 10 microg/ml). We conclude that MXF suppresses the secretion of proinflammatory cytokines in human monocytes and THP-1 cells and that it exerts its anti-inflammatory effects in THP-1 cells by inhibiting NF-kappaB, ERK, and JNK activation. Its anti-inflammatory properties should be further assessed in clinical settings.