Immune response modulation using Tolfenamic acid as an effective therapeutic for Burkholderia pseudomallei infection
Wilson, William J., author
Hanneman, William, advisor
Slayden, Richard, committee member
Legare, Marie, committee member
Tjalkens, Ronald, committee member
Melioidosis is a tropical, often fatal, disease caused by the aerobic, Gram-negative facultative intracellular bacterium Burkholderia pseudomallei. Despite its growing global burden and high fatality rate, little is known about the disease. Recent studies demonstrate that Cyclooxygenase-2 (COX-2) inhibition is an effective post-exposure therapeutic to pulmonary melioidosis by inhibiting the production of Prostaglandin E2 (PGE2). However, this effective treatment was conducted using an experimental COX-2 inhibitor which is not approved for human or animal use, therefore, an alternative COX-2 inhibitor needs to be identified for further studies. Tolfenamic acid (TA) is a non-steroidal anti-inflammatory drug (NSAID) developed for COX-2 inhibition and is marketed outside of the United States for the treatment of migraines. While this drug was developed for COX-2 inhibition, it has been found to modulate other aspects of inflammation. In this study, we analyzed the effect of TA on cell survival, regulation of COX-2 and Nuclear factor- kappaB (NF-ĸB) protein expression as well as PGE2 production using RAW 264.7 cells infected with B. pseudomallei. We used this information to develop a protocol to evaluate the effectiveness of post-exposure treatment with TA as a therapeutic and compared these results to effective Ceftazidime treatments and the co-treatment of TA with a sub-therapeutic treatment of Ceftazidime in BALB/c mice. TA effectively increased cell viability in vitro and was able to reduce COX-2 expression and PGE2 production while also decreasing NF-ĸB activation during infection. Oral administration of TA to BALB/c mice infected with B. pseudomallei was able to significantly increase survival outcome, however, this did not alter bacterial load or dissemination within organ tissues. The co-treatment of TA with a sub-therapeutic treatment of Ceftazidime was able to substantially increase survival outcome and clear the bacterial load within organ tissue. We demonstrate that post-exposure treatment with TA and sub-therapeutic Ceftazidime is effective to treat melioidosis in BALB/c mice. Additionally, we further elucidate the inflammatory response to B. pseudomallei.
Includes bibliographical references.