Caveolin-1-deficient mice show defects in innate immunity and inflammatory immune response during Salmonella enterica serovar typhimurium infection

A number of studies have shown an association of pathogens with caveolae. To this date, however, there are no studies showing a role for caveolin-1 in modulating immune responses against pathogens. Interestingly, expression of caveolin-1 has been shown to occur in a regulated manner in immune cells in response to lipopolysaccharide (LPS). Here, we sought to determine the role of caveolin-1 (Cav-1) expression in Salmonella pathogenesis. Cav-1^-/- mice displayed a significant decrease in survival when challenged with Salmonella enterica serovar Typhimurium. Spleen and tissue burdens were significantly higher in Cav-1^-/- mice. However, infection of Cav-1^-/- macrophages with serovar Typhimurium did not esult in differences in bacterial invasion. In addition, Cav-1^-/- mice displayed increased production of inflammatory cytokines, chemokines, and nitric oxide. Regardless of this, Cav-1^-/- mice were unable to control the systemic infection of Salmonella. The increased chemokine production in Cav-1^-/- mice resulted in greater infiltration of neutrophils into granulomas but did not alter the number of granulomas present. This was accompanied by increased necrosis in the liver. However, Cav-1^-/- macrophages displayed increased inflammatory responses and increased nitric oxide production in vitro in response to Salmonella LPS. These results show that caveolin-1 plays a key role in regulating anti-inflammatory responses in macrophages. Taken together, these data suggest that the increased production of toxic mediators from macrophages lacking caveolin-1 is likely to be responsible for the marked susceptibility of caveolin-1-deficient mice to S. enterica serovar Typhimurium.