Neutrophil recruitment to the site of acute inflammation is a multistep process regulated by specific signaling molecules. The signaling mechanisms that regulate neutrophil-endothelial cell interactions remain incompletely understood. p38 mitogen-activated protein kinase (MAPK) signalling was shown to regulate different steps of neutrophil migration in response to inflammatory stimuli. The mitogen- and stress-activated protein kinase-1 (MSK1) can be activated by either extracellular-signal-regulated kinase (ERK) 1/2 or p38 MAPK. The aim of the present study is to investigate the effects of pharmacological suppression of MSK1 by its specific inhibitor, SB747651A, on various steps of neutrophil recruitment. In vivo studies were conducted using real-time and time-lapsed intravital video microscopy of the cremaster microcirculation to determine the dynamic leukocyte-endothelial cell interactions. Intrascrotal injection of macrophage inflammatory protein-2 (MIP-2, 0.2 μg/mouse) decreased leukocyte rolling velocity which was significantly reversed by pre-treatment with SB747651A (intrascrotal injection of 3 mg/kg). SB747651A pre-treatment enhanced MIP-2-induced increase in neutrophil adhesion and emigration. To better understand the effect of SB747651A on different steps of neutrophil recruitment, we placed a small piece of MIP-2-containing agarose gel on the exposed cremaster muscle and studied directed migration of neutrophils in the postcapillary venule and in the tissue. Superfusion of SB747651A (5 μM) on cremaster muscle subjected to MIP-2 gradient significantly increased rolling velocity and adhesion, but decreased emigration of neutrophils in comparison to superfusion of normal saline III without SB747651A. SB747651A treatment significantly affected transmigration time, detachment time, intravascular crawling and the velocity of migration, but not the directionality of migrating neutrophils in tissue. The expression of intercellular adhesion molecule-1 (ICAM-1) in cultured endothelial cells was up-regulated by co-treatment with SB747651A and MIP-2 but not by MIP-2 alone. Flow cytometry analysis showed that co-treatment of bone marrow neutrophils with SB747651A and MIP-2 significantly decreased macrophage antigen-1 (Mac-1) but not lymphocyte function associated antigen-1 (LFA-1) expression as compared with MIP-2 treatment alone. Collectively, our findings demonstrate that pharmacological suppression of MSK1 by SB747651A affects multiple steps of MIP-2-induced neutrophil recruitment in vivo.

Pseudomonas aeruginosa-induced pneumonia is serious problem that results in severe inflammation response and high mortality in the host. Interleukin-1£] (IL-1£]) is one of the major extracellular proinflammatory cytokines thought to be involved in many acute and chronic lung diseases. To investigate the role of caspase-1, IL-1£] and macrophage inflammatory protein-2 (MIP-2) in P. aeruginosa pneumonia induced lung damage, C57BL/6 (WT) and CASP-1-/- mice were subjected to pneumonia induced by intratracheal injection of P. aeruginosa. The lung permeability, bacterial content in blood and lung, lung myeloperoxidase (MPO) activity, total cell counts and protein in bronchoalveolar lavage fluid (BALF), NF-£eB activation as well as expression of IL-1£] and MIP-2 were assayed at 8 hr after P. aeruginosa injection. The IL-1£] inhibitor, anakinra, was also used to evaluate the role of IL-1£]. P. aeruginosa injection increased the lung permeability, lung MPO activity, bacterial counts in blood, total cell counts and protein in BALF, NF-£eB activation and expression of IL-1£] and MIP-2 in WT mice; and these increases were all decreased by administration of anakinra in WT mice or in CASP-1-/- mice. Furthermore, the lung MPO activity, total protein in BALF and expression of IL-1£] and MIP-2 were decreased in CASP-1-/- ¡÷ WT but not in WT ¡÷ CASP-1-/- chimeric mice, suggesting that pneumonia induced lung damage and IL-1£] and MIP-2 expressions depend on caspase-1 signaling of the resident cells.

Ticks are blood feeding parasites that secrete a number of immunomodulatory factors to evade host immune response. The aim of this study was to prepare a tick salivary protein with anti-chemokine activity and to observe the influence of salivary gland extrakt on neutrophile´s chemotaxis.

No description available.

<p> Lung disease is the leading threat to human health worldwide. In particular, two threats are responsible for the majority of the pulmonary disease burden: infection and tobacco smoke exposure. Efforts to combat these diseases have been hampered by gaps in our understanding of the complex interactions between environmental threats and the host's own immune defences. Indeed, much of the pulmonary disease burden should be ascribed not to direct smoke-, virus-or bacteria-induced damage, but to maladaptive host defence responses against these threats. This is an understudied topic. Efforts to redress this deficiency have been hampered by the lack of available animal models. Thus, the present studies developed and examined models of Heterologous pulmonary infection, in which hosts must defend against two different infections, and of tobacco smoke exposure. In the first study, a critical role for MIP-2 driven pulmonary neutrophilia was elucidated in the pathology associated with bacterial superinfection of influenza virus infection. This study further demonstrated that the timing and sequence in which pathogens were encountered played important roles in determining the outcome of disease, and that viral and bacterial infections have different but long-lived impacts on alveolar macrophages. In the second study, it was determined that cigarette smoke exposure impacts host defence without exhausting T-or B-cells. Collectively, these studies have advanced our understanding of complex lung pathologies, and suggest an important role for the innate immune system in mediating such diseases. </p> / Thesis / Doctor of Philosophy (PhD)

No description available.