Aquaporins in Infection and Inflammation

Abstract

About the cover:The front cover displays a human, blood-derived macrophage stained for aquaporin 9.During the course of the research underlying this thesis, Angelika Holm was enrolled in Forum Scientium, a multidisciplinary doctoral programme at Linköping University Printed by LiU-Tryck, Linköping, Sweden, 2016 "Be brave, even if you're not, pretend to be. No one can tell the difference."To that young, awkward, tall girl who dared to dream of something else, something more:You did it. SUPERVISOR Elena VikströmDepartment of Clinical and Experimental Medicine Linköping University Linköping Sweden When cells of the innate immune system encounter pathogens they need to respond and prepare for migration and phagocytosis and do so through volume regulatory processes. The Gramnegative bacterium Pseudomonas aeruginosa utilizes a small molecule-based communication system, called quorum sensing (QS) to control the production of its virulence factors and biofilms. We found that P. aeruginosa with a complete QS system elicits a stronger phagocytic response in human blood-derived macrophages compared to its lasI-/rhlI-mutant lacking the production of the QS molecules N-butyryl-L-homoserine lactone (C4-HSL) and N-3-oxododecanoyl-L-homoserine lactone (3O-C12-HSL). Infection with P. aeruginosa further increases the expression of AQP9 and induces re-localisation of AQP9 to the front and trailing ends of macrophages. Moreover, the 3O-C12-HSL alone elevates the expression of AQP9, redistribute the water channel to the front and rear ends and increases the cell area and volume of macrophages. Both infection with the wild type P. aeruginosa and the treatment with 3O-C12-HSL change the nano-structural architecture of the AQP9 distribution in macrophages. ASSISTANT SUPERVISORS Karl-Eric MagnussonViruses use the intracellular machinery of the invaded cells to produce and assemble new viral bodies. Intracellular AQPs are localised in a membranes of cellular organelles to regulate their function and morphology. C3H10T1/2 fibroblasts transiently expressing green fluorescent protein (GFP)-AQP6 show a reduced expression of AQP6 after Hazara virus infection and an increased cell area. Overexpressing AQP6 in C3H10T1/2 cells reduces the infectivity of Hazara virus indicating that AQP6 expression has a protective role in virus infections.Ion and water channels in the epithelial cell lining tightly regulate the water homeostasis. In microscopic colitis (MC), patients suffer from severe watery diarrhoeas. For the first time, we have shown that the expression of AQP1, 8 and 11 and the sodium/hydrogen exchanger NHE1 are reduced in colonic biopsies from MC patients compared to healthy control individuals. Following treatment with the glucocorticoid budesonide the patients experienced a rapid recovery and we observed a restored or increased expression of the AQPs and NHE1 during treatment, suggesting a role for AQPs in the diarrhoeal mechanisms in MC.Taken together, this thesis provides new evidence on the importance of water homeostasis regulatio...

Aquaporin-9 Contributes to the Maturation Process and Inflammatory Cytokine Secretion of Murine Dendritic Cells

“…We focused on the modulation of the inflammatory response. In a preliminary dose-response study, we identified 25 μg as the most efficient concentration for AQP9 inhibition in BMDCs, in line with what has been previously reported using macrophages ( 22 ). Furthermore, we observed a stronger reduction of inflammatory cytokines release after two consecutive administrations of the chemical inhibitor (Supplementary Figure 2 ).…”

“…To evaluate the biological significance of Aqp 9 expression during DCs maturation, we investigated whether a chemical blockade of AQP9 with a specific inhibitor, HTS13286 ( 22 ), could affect DCs response to an inflammatory stimulus. We focused on the modulation of the inflammatory response.…”

“…On day 7 BMDCs were stimulated with 1 μg/mL of LPS (L6143, Sigma-Aldrich, St Louis, MO, USA) and supernatants were collected 24 h after LPS stimulation. For the treatment with AQP9 inhibitor, BMDCs were treated with 25 μm of HTS13286 (Maybridge, Cornwall, UK) ( 22 ) at day 7, immediately after LPS stimulation. A second stimulation with HTS13286 was carried out 3 h after LPS.…”

“…We show that Aqp 9 is frequently the most expressed Aqp in DCs, and its expression is upregulated following LPS exposure. Aqp9 chemical inhibition ( 22 ) reduces inflammatory cytokines secretion. Therefore, we compared WT and AQP9-KO BMDCs maturational profiles, demonstrating that AQP9 is required for efficient DCs maturation and to trigger the inflammatory response.…”

Ambiente de otimização dinâmica e simulação para obtenção de perfis de velocidade ótimos de veículos pesados com calibração simplificada

“…Nos métodos que não usam sensores inerciais, alguns estudos usam um modelo de veículo que descreve sua dinâmica longitudinal e outro modelo para a topografia do trajeto (HOLM, 2011;SAHLHOLM et al, 2007). Outra abordagem é baseada em um observador adaptativo e uma estimativa recursiva do estado do dinâmico do sistema (MAHYUDDIN et al, 2012).…”