Glycogen synthase kinase-3ß inhibition improved survivability of mice infected with Burkholderia pseudomallei.

The disease melioidosis, caused by the soil bacteria Burkholderia pseudomallei, often manifests as acute septicemia with high fatality. Glycogen synthase kinase-3ß (GSK3ß) plays a key role during the inflammatory response induced by bacteria. We used a murine model of acute melioidosis to investigate the effects of LiCl, a GSK3 inhibitor on experimental animal survivability as well as TNF-α, IL-1ß, IFN-γ, IL-10 and IL-1Ra cytokine levels in blood, lung, liver and spleen of B. pseudomallei-infected mice. Our results showed that administration of 100 µg/g LiCl improved survivability of mice infected with 5 X LD50 of B. pseudomallei. Bacterial counts in spleen, liver and lungs of infected mice administered with LiCl were lower than non-treated controls. Our data also revealed that GSK3ß is phosphorylated in the spleen, liver and lung of animals infected with B. pseudomallei. However in infected animals administered with LiCl, higher levels of pGSK3 were detected in the organs. Levels of proinflammatory cytokines (TNF-α, IL-1ß and IFN-γ) and anti-inflammatory cytokines (IL-10 and IL-1Ra) in sera and organs tested were elevated significantly following B. pseudomallei infection. With GSK3ß inhibition, pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1ß) were significantly decreased in all the samples tested whilst the levels of anti-inflammatory cytokines, IL-10 (spleen and lung) and IL-1Ra (spleen, liver and sera) were further elevated. This study represents the first report implicating GSK3ß in the modulation of cytokine production during B. pseudomallei infection thus reiterating the important role of GSK3ß in the inflammatory response caused by bacterial pathogens.

Glycogen synthase kinase-3β inhibition improved survivability of mice infected with Burkholderia pseudomallei

The disease melioidosis, caused by the soil bacteria Burkholderia pseudomallei, often manifests as acute septicemia with high fatality. Glycogen synthase kinase-3β (GSK3β) plays a key role during the inflammatory response induced by bacteria. We used a murine model of acute melioidosis to investigate the effects of LiCl, a GSK3 inhibitor on experimental animal survivability as well as TNF-α, IL-1β, IFN-γ, IL-10 and IL-1Ra cytokine levels in blood, lung, liver and spleen of B. pseudomallei-infected mice. Our results showed that administration of 100 μg/g LiCl improved survivability of mice infected with 5 X LD50 of B. pseudomallei. Bacterial counts in spleen, liver and lungs of infected mice administered with LiCl were lower than non-treated controls. Our data also revealed that GSK3β is phosphorylated in the spleen, liver and lung of animals infected with B. pseudomallei. However in infected animals administered with LiCl, higher levels of pGSK3 were detected in the organs. Levels of proinflammatory cytokines (TNF-α, IL-1β and IFN-γ) and anti-inflammatory cytokines (IL-10 and IL-1Ra) in sera and organs tested were elevated significantly following B. pseudomallei infection. With GSK3β inhibition, pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β) were significantly decreased in all the samples tested whilst the levels of anti-inflammatory cytokines, IL-10 (spleen and lung) and IL-1Ra (spleen, liver and sera) were further elevated. This study represents the first report implicating GSK3β in the modulation of cytokine production during B. pseudomallei infection thus reiterating the important role of GSK3β in the inflammatory response caused by bacterial pathogens.

Characterization of a novel protein in chick intestine that exhibits calcium-binding activity and regulation by dietary calcium, aluminum and vitamin D.

The molecular mechanisms stimulated by vitamin D and low calcium diets that promote intestinal calcium absorption are not fully understood. In the present experiments, groups of chicks were subjected to the following treatments known to alter the efficiency of Ca absorption: vitamin D deficiency, repletion of vitamin D-deficient chicks with 1,25-dihydroxycholecalciferol [1,25(OH)2D3], low Ca intakes, and aluminum toxicity. Duodenal mucosal scrapings were obtained and screened for changes in protein composition using SDS-PAGE and size exclusion chromatography. The relative amount of a previously unreported 400-kDa oligomer containing 22-kDa monomeric subunits was found to vary directly with theoretical changes in the efficiency of Ca absorption, i.e., amounts increased with low Ca intakes and repletion with 1,25(OH)2D3, but were decreased by dietary aluminum and vitamin D deficiency. The oligomer was shown to have Ca-binding activity using a 45Ca overlay technique. These properties suggest 1) that the protein is regulated, at least indirectly, by 1,25(OH)2D3; 2) that the protein may play a role in promoting Ca absorption, possibly by binding Ca; and 3) that dietary aluminum interferes with the regulation of this protein, possibly by interfering with the actions of vitamin D in the intestine.