Natural killer T cells (NKT) are an important subset of T lymphocytes. They are unique in their ability to produce both T helper 1 and T helper 2 associated cytokines, thus being capable of steering the immune system ...Natural killer T cells (NKT) are an important subset of T lymphocytes. They are unique in their ability to produce both T helper 1 and T helper 2 associated cytokines, thus being capable of steering the immune system into either inflammation or tolerance. Disruption of NKT cell numbers or function results in severe deficits in immune surveillance against pathogens and tumor cells. Growing experimental evidence suggests that hepatosteatosis may reduce resident hepatic as well as peripheral NKT cells. Those models of hepatosteatosis and the change in NKT cell numbers are associated with a disruption of cytokine homeostasis, resulting in a more pronounced release of proinflammatory cytokines which renders the steatotic liver highly susceptible to secondary insults. In this letter to the editor, we focus on recently published data in the World Journal of Gastroenterology by Xu and colleagues demonstrating reduced peripheral NKT cells in patients with non-alcoholic fatty liver disease, compare those findings with ours and others in different animal models of hepatosteatosis, and hypothesize about the potential underlying mechanism.展开更多
Objective:To investigate whether the increase of tumor necrosis factor alpha is dependent on lipidic component of malarial pigment.Methods:Adherent human monocytes were fed for 3 hours with different meals(native hemo...Objective:To investigate whether the increase of tumor necrosis factor alpha is dependent on lipidic component of malarial pigment.Methods:Adherent human monocytes were fed for 3 hours with different meals(native hemozoin;lipid free hemozoin;and control latex particles),then tumor necrosis factor alpha was monitored in cell supernatants up to 48 hours through western blotting or specific enzyme-linked immunoadsorbent assay.In selected experiments,unfed monocytes were treated with different doses of 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid or 4-hydroxynonenal instead of phagocytosis.Results:Hemozoin-fed monocytes produced higher levels of tumor necrosis factor alpha than unstimulated and latex-fed cells, while lipid-free hemozoin did not reproduce these results.Additionally,hemozoin effects were mimicked dose-dependently by 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid,but not by 4-hydroxynonenal.Conclusions:Present data suggest an essential role for lipids in hemozoindependent enhanced release of tumor necrosis factor alpha from monocytes,and 15(S,R)hydroxy -6,8,11,13-eicosatetraenoic acid could be one possible specific mediator.展开更多
文摘Natural killer T cells (NKT) are an important subset of T lymphocytes. They are unique in their ability to produce both T helper 1 and T helper 2 associated cytokines, thus being capable of steering the immune system into either inflammation or tolerance. Disruption of NKT cell numbers or function results in severe deficits in immune surveillance against pathogens and tumor cells. Growing experimental evidence suggests that hepatosteatosis may reduce resident hepatic as well as peripheral NKT cells. Those models of hepatosteatosis and the change in NKT cell numbers are associated with a disruption of cytokine homeostasis, resulting in a more pronounced release of proinflammatory cytokines which renders the steatotic liver highly susceptible to secondary insults. In this letter to the editor, we focus on recently published data in the World Journal of Gastroenterology by Xu and colleagues demonstrating reduced peripheral NKT cells in patients with non-alcoholic fatty liver disease, compare those findings with ours and others in different animal models of hepatosteatosis, and hypothesize about the potential underlying mechanism.
基金supported in the context of the Italian Malaria Network by grants from Compagnia di San Paolo-IMI and from Regione Piemonte,Ricerca Sanitaria Finalizzata 2008bis to PA
文摘Objective:To investigate whether the increase of tumor necrosis factor alpha is dependent on lipidic component of malarial pigment.Methods:Adherent human monocytes were fed for 3 hours with different meals(native hemozoin;lipid free hemozoin;and control latex particles),then tumor necrosis factor alpha was monitored in cell supernatants up to 48 hours through western blotting or specific enzyme-linked immunoadsorbent assay.In selected experiments,unfed monocytes were treated with different doses of 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid or 4-hydroxynonenal instead of phagocytosis.Results:Hemozoin-fed monocytes produced higher levels of tumor necrosis factor alpha than unstimulated and latex-fed cells, while lipid-free hemozoin did not reproduce these results.Additionally,hemozoin effects were mimicked dose-dependently by 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid,but not by 4-hydroxynonenal.Conclusions:Present data suggest an essential role for lipids in hemozoindependent enhanced release of tumor necrosis factor alpha from monocytes,and 15(S,R)hydroxy -6,8,11,13-eicosatetraenoic acid could be one possible specific mediator.
